阅读说明：本技术 电动作业机 (Electric working machine ) 是由 市川佳孝 小早川忠彦 于 2019-09-11 设计创作，主要内容包括：本公开的一个方面的电动作业机具备马达、操作部以及控制部。马达从电池组接受电力供给而进行驱动。操作部供操作而使马达驱动。控制部响应于操作部受到了操作这个情况而使马达启动,并获取与电池组的放电状态相关的状态信息,该控制部基于所获取到的状态信息,以抑制由电池组进行的保护动作执行的方式控制马达的驱动。(An electric working machine according to an aspect of the present disclosure includes a motor, an operation unit, and a control unit. The motor is driven by receiving power supply from the battery pack. The operation part is used for operating and driving the motor. The control unit starts the motor in response to the operation of the operation unit and acquires state information relating to the discharge state of the battery pack, and controls the driving of the motor based on the acquired state information so as to suppress the execution of a protection operation by the battery pack.)

1. An electric working machine that operates by receiving power supply from a battery pack that performs a protective operation in response to occurrence of an overload, comprising:

a motor that receives power supply from the battery pack and drives the battery pack;

an operation unit configured to be operated to start the motor; and

and a control unit configured to start the motor in response to an operation of the operation unit and acquire state information on a discharge state of the battery pack, wherein the control unit controls driving of the motor so as to suppress the battery pack from performing the protective operation, based on the acquired state information.

2. The electric working machine according to claim 1,

the control unit is configured to change a control parameter of the motor related to the supplied power before the protection operation is performed by the battery pack based on the state information.

3. The electric working machine according to claim 2,

the control unit changes the control parameter so as to limit the supply power based on the state information.

4. The electric working machine according to claim 2 or 3,

the status information includes information relating to a precursor to the battery pack performing the protective action.

5. The electric working machine according to any one of claims 2 to 4,

the control parameter includes a value of a discharge current flowing from the battery pack to the motor,

the control unit limits the value of the discharge current based on the state information.

6. The electric working machine according to claim 1,

the control unit is configured to stop the motor before the battery pack performs the protection operation based on the state information.

7. The electric working machine according to any one of claims 1 to 6,

the state information includes an accumulated value for the battery pack to perform the protective action, which is obtained by accumulating an added value corresponding to a value of a discharge current supplied from the battery pack to the motor,

the control portion is configured to control driving of the motor using the accumulated value as a battery protection value.

8. The electric working machine according to any one of claims 1 to 6,

the state information includes mapping information for calculating an accumulated value used by the battery pack to perform the protection action,

the control unit is configured to detect a discharge relation value related to discharge, calculate a battery protection value based on the detected discharge relation value and the map information, and control driving of the motor using the calculated battery protection value,

the battery protection value is a value corresponding to the accumulated value calculated by accumulating the added value corresponding to the discharge relation value in the map information by the battery pack.

9. The electric working machine according to claim 8,

the discharge relation value is a value of a discharge current flowing from the battery pack to the electric working machine.

10. The electric working machine according to claim 8 or 9,

the status information includes the accumulated value and the status information,

the control unit is configured to set the accumulated value acquired from the battery pack as the battery protection value in response to acquisition of the accumulated value from the battery pack.

11. The electric working machine according to claim 10,

the control unit is configured to calculate the battery protection value by adding the accumulated value obtained from the battery pack to the added value corresponding to the detected discharge relation value in the past and the map information.

12. The electric working machine according to any one of claims 7 to 11,

the battery pack is configured to perform the protective action in response to the accumulated value exceeding a protective threshold,

the control unit is configured to change a control parameter of the motor related to the supply power so as to limit the supply power in response to a case where the battery protection value exceeds a limit threshold value smaller than the protection threshold value.

13. The electric working machine according to any one of claims 7 to 12,

the state information includes map information indicating a correspondence between a value of a discharge current flowing from the battery pack to the motor and the addition value,

the battery pack is configured to perform the protective action in response to the accumulated value exceeding a protective threshold,

the control unit is configured to detect the discharge current, predict a time until the battery pack performs the protection operation based on the battery protection value, the detected value of the discharge current, and the map information, and change a control parameter of the motor related to the supply power so as to limit the supply power in response to a case where the predicted time is shorter than a time threshold.

14. The electric working machine according to any one of claims 7 to 11,

the battery pack is configured to perform the protective action in response to the accumulated value exceeding a protective threshold,

the control unit is configured to stop the motor in response to a situation in which the battery protection value exceeds a stop threshold value smaller than the protection threshold value.

15. The electric working machine according to claim 14,

the stop threshold includes a first stop threshold and a second stop threshold greater than the first stop threshold,

the control unit is configured to restart the motor in response to the operation unit being operated after the motor is stopped in response to the battery protection value exceeding the first stop threshold, and to prohibit the motor from being restarted before the battery protection value becomes lower than the first stop threshold after the motor is stopped in response to the battery protection value exceeding the second stop threshold.

16. The electric working machine according to claim 12,

the state information includes map information indicating a correspondence between a value of a discharge current flowing from the battery pack to the motor and the addition value,

the control unit is configured to detect a value of the discharge current, and set the limiting threshold value based on the detected value of the discharge current and the acquired map information.

17. The electric working machine according to claim 16,

the state information includes a battery temperature of the battery pack and the mapping information corresponding to different battery temperatures,

the control unit sets the limit threshold value based on the detected value of the discharge current, the acquired battery temperature, and the acquired map information.

18. The electric working machine according to any one of claims 1 to 7,

the state information includes a remaining capacity of the battery pack,

the battery pack performs the protective action in response to the remaining capacity being below a first capacity threshold,

the control unit is configured to change a control parameter of the motor related to the supply power so as to limit the supply power in response to a case where the remaining capacity is lower than a second capacity threshold larger than the first capacity threshold.

19. The electric working machine according to any one of claims 1 to 7,

the state information includes a battery temperature of the battery pack,

the battery pack performs the protective action in response to the battery temperature exceeding a first temperature threshold,

the control unit changes a control parameter related to the supply power so as to limit the supply power in response to a case where the battery temperature exceeds a second temperature threshold smaller than the first temperature threshold.

20. The electric working machine according to any one of claims 2 to 5, 12, 13, 18, and 19,

the control unit performs PWM control, which is pulse width modulation, of the motor,

the control parameter includes a duty ratio in the PWM control.

21. The electric working machine according to any one of claims 2 to 5, 12, 13, and 18 to 20,

the control unit acquires the state information from before the motor is driven, and changes the control parameter based on the state information from before the motor is driven.

22. The electric working machine according to any one of claims 1 to 21,

further comprises a main power switch for supplying power to the control unit,

the control portion starts requesting the state information for the battery pack from a time after the main power switch is turned on and before the motor is driven.

23. The electric working machine according to any one of claims 1 to 22,

the control part acquires the state information transmitted from the battery pack by serial communication,

the frequency of the serial communication when current flows from the battery pack to the motor is higher than the frequency of the serial communication when current does not flow from the battery pack to the motor.

24. The electric working machine according to any one of claims 1 to 23,

the control unit sets an upper current limit value for a discharge current flowing from the battery pack to the motor based on the acquired state information, and controls the value of the discharge current to be equal to or less than the set upper current limit value.

Technical Field

The present disclosure relates to an electric working machine.

Background

The electric working machine described in patent document 1 is operated by receiving power supply from a battery pack in which a plurality of battery cells are connected in series. The battery pack outputs a discharge prohibition signal to the electric working machine when a state in which the voltage value of any one of the plurality of battery cells is lower than the threshold value continues for a certain period of time. When a discharge prohibition signal is input from the battery pack, the electric working machine stops the switching element that controls the current of the motor, thereby protecting the battery pack.

Patent document 1: japanese patent laid-open publication No. 2005-131770

The battery pack may also fail in the case where a large current flows for a long period of time. Therefore, even in such an overcurrent state, it is desirable to protect the battery pack by outputting a discharge prohibition signal from the battery pack. However, when the load of the work implement becomes high, the current flowing from the battery pack to the work implement becomes large. Therefore, if the battery pack is inhibited from discharging in the overcurrent state, the battery pack is frequently inhibited from discharging when the load of the work machine is high, which leads to a problem of a decrease in work efficiency.

Disclosure of Invention

The present disclosure provides an electric working machine which operates a protection function of a battery pack when protection is to be performed and improves convenience for a user.

One aspect of the present disclosure is an electric working machine that operates by receiving power supply from a battery pack that performs a protective operation in response to occurrence of an overload, the electric working machine including a motor, a switch, and a control unit. The motor is driven by receiving power supply from the battery pack. The switch is configured to be operated to activate the motor. The control unit is configured to start the motor in response to the switch being operated, and acquire state information relating to a discharge state of the battery pack, and the control unit controls the driving of the motor in a manner that suppresses the battery pack from performing a protective operation, based on the acquired state information.

The control unit of the electric working machine acquires state information related to the discharge state of the battery pack. And if the battery pack is overloaded, executing protection action. Therefore, the control unit controls the driving of the motor based on the acquired state information so as to suppress the battery pack from performing a protective operation. This makes it possible to continue the work performed by the electric working machine while suppressing the execution of the protection operation by the battery pack. At this time, the condition for the battery pack to perform the protection operation is not changed. This makes it possible to perform a protection operation when the battery pack is to be protected, and to improve the convenience of the user.

The control unit may be configured to change a control parameter of the motor related to the supplied power before the protection operation is performed by the battery pack based on the state information.

The control unit changes the control parameter of the motor related to the supplied power before the battery pack performs the protective operation, thereby suppressing the performance of the protective operation by the battery pack and enabling the work by the electric working machine to be continued.

The control unit may be configured to change the control parameter so as to limit the supply power based on the state information.

The control unit changes the control parameter so as to limit the supply power, thereby limiting the supply power before the battery pack performs the protection operation. As a result, the load accumulation of the battery pack is suppressed, and therefore, the work by the electric working machine can be continued without executing the protection operation by the battery pack.

The state information may include information on a sign that the battery pack performs a protection operation.

Since the state information includes information on a sign of performing the protection operation, the control unit can recognize the sign before the battery pack performs the protection operation. Further, the control unit may change the control parameter so as not to perform the protection operation, that is, so as to suppress the accumulation of the load of the battery pack, before the battery pack performs the protection operation.

The control parameter may include a value of a discharge current flowing from the battery pack to the motor, and the control unit may limit the value of the discharge current based on the state information.

The control unit limits the discharge current, thereby limiting the supply power before the battery pack performs the protection operation. As a result, although the output of the electric working machine is reduced, the user can continue the work performed by the electric working machine without performing the protection operation by the battery pack.

The control unit may be configured to stop the motor before the battery pack performs the protection operation based on the state information.

Since the battery pack performs the protection operation, the electric working machine cannot be used for a relatively long time. Therefore, by stopping the motor by the control unit before the protection operation by the battery pack is executed, the battery pack can be recovered in a relatively short time, and the operation by the electric working machine can be restarted.

The state information may include an accumulated value for the battery pack to perform the protection operation, which is obtained by accumulating an added value corresponding to a value of the discharge current supplied from the battery pack to the motor. The control unit may be configured to control the driving of the motor using the accumulated value as the battery protection value.

The control unit acquires an accumulated value for the battery pack to perform the protection operation from the battery pack. Thus, the control unit can control the driving of the motor so as to suppress the battery pack from performing the protective operation, using the acquired accumulated value.

In addition, the state information may also include mapping information for calculating an accumulated value used by the battery pack to perform the protection action. The control unit may be configured to detect a discharge relation value related to discharge, calculate a battery protection value from the detected discharge relation value and the map information, and control driving of the motor using the calculated battery protection value. The battery protection value may be a value corresponding to an accumulated value calculated by accumulating the added values corresponding to the discharge relation values in the map information by the battery pack.

The control unit acquires map information for calculating an accumulated value for the battery pack to perform a protection operation, and calculates a battery protection value corresponding to the accumulated value using the acquired map information. Thus, the control unit can control the driving of the motor so as to suppress the battery pack from performing a protection operation, using the calculated battery protection value.

The discharge relation value may be a value of a discharge current flowing from the battery pack to the electric working machine.

The battery protection value can be calculated using the detected value of the discharge current as the discharge relation value.

The status information may include an accumulated value. The control unit may be configured to set the accumulated value acquired from the battery pack as the battery protection value in response to the acquisition of the accumulated value from the battery pack.

The control portion sets the accumulated value acquired from the battery pack as the battery protection value in response to the acquisition of the accumulated value from the battery pack. Therefore, the control unit uses the same value as the value used by the battery pack to perform the protection operation as much as possible, and therefore can detect the indication that the battery pack performs the protection operation with high accuracy.

The control unit may be configured to calculate the battery protection value by adding the past accumulated value acquired from the battery pack to an added value corresponding to the detected discharge relation value in the map information.

The control unit calculates a battery protection value by adding the accumulated value acquired from the battery pack in the past and the added value. Therefore, the control unit can use the value for the battery pack to perform the protection operation as much as possible. Further, the control unit can update the battery protection value while using the value for the battery pack to perform the protection operation as much as possible and while the accumulated value cannot be obtained between communications or when communications are temporarily interrupted. This makes it possible to detect the sign of the battery pack performing the protection operation with high accuracy.

In addition, the battery pack may be configured to perform the protection operation in response to the accumulated value exceeding the protection threshold value. The control unit may be configured to change the control parameter of the motor related to the supplied power so as to limit the supplied power in response to the battery protection value exceeding a limit threshold value smaller than the protection threshold value.

When the battery protection value exceeds a limit threshold value smaller than the protection threshold value, a control parameter related to the supply power of the motor is changed so as to limit the supply power. This suppresses an increase in the accumulated value and the battery protection value. As a result, the execution of the protection operation by the battery pack is suppressed, and the motor can continue to receive the supply of electric power from the battery pack.

The state information may include map information indicating a correspondence relationship between the value of the discharge current flowing from the battery pack to the motor and the added value. The battery pack may be configured to perform the protection operation in response to the accumulated value exceeding the protection threshold value. The control unit may be configured to detect a discharge current, predict a time until the battery pack performs a protection operation based on the battery protection value, the value of the detected discharge current, and the map information, and change the control parameter of the motor related to the supply power so as to limit the supply power in response to a case where the predicted time is shorter than a time threshold.

A time until the battery pack performs a protection operation is predicted, and in response to the predicted time being shorter than a time threshold, a control parameter relating to the supply power of the motor is changed so as to limit the supply power. This suppresses an increase in the accumulated value and the battery protection value. As a result, the execution of the protection operation by the battery pack is suppressed, and the motor can continue to receive the supply of electric power from the battery pack.

In addition, the battery pack may be configured to perform the protection operation in response to the accumulated value exceeding the protection threshold value. The control unit may be configured to stop the motor in response to the battery protection value exceeding a stop threshold value smaller than the protection threshold value.

If the battery protection value exceeds a stop threshold value smaller than the protection threshold value, the motor is stopped. Thereby, the accumulated value and the battery protection value are reduced. As a result, the battery pack can be recovered in a shorter motor stop period than in the case where the protection operation by the battery pack is performed. Further, the motor can restart the supply and demand of electric power from the battery pack after a relatively short stop period.

The stop threshold value may include a first stop threshold value and a second stop threshold value. The second stop threshold is greater than the first stop threshold. The control unit may stop the motor in response to the battery protection value exceeding the first stop threshold value, and then restart the motor in response to the switch being operated. In addition, the control unit may be configured to prohibit the restart of the motor until the battery protection value becomes lower than the first stop threshold value after stopping the motor in response to the battery protection value exceeding the second stop threshold value.

The motor is stopped in response to the battery protection value exceeding the first stop threshold, and then restarted in response to the operation of the operation unit. Further, in response to the battery protection value exceeding a second stop threshold, the motor is stopped, and the restart of the motor is stopped before the battery protection value is lower than the first stop threshold. Thus, after the motor is temporarily stopped, the user can continue to use the electric working machine by operating the operation unit, and can recognize that the period in which the electric working machine becomes unusable has come by continuing to use the electric working machine.

The state information may include map information indicating a correspondence relationship between the value of the discharge current flowing from the battery pack to the motor and the added value. The control unit may be configured to detect a value of the discharge current and set the limit threshold value based on the detected value of the discharge current and the acquired map information.

By including the mapping information in the state information, the control section can change the limit threshold in response to the value of the discharge current. Further, the control unit can appropriately limit the supply power in response to the value of the discharge current.

The state information may include a battery temperature of the battery pack and map information corresponding to different battery temperatures. The control unit may set the limit threshold value based on the detected magnitude of the discharge current, the acquired battery temperature, and the acquired map information.

By including the map information corresponding to different battery temperatures in the state information, the control section can vary the limit threshold in response to the values of the battery temperature and the discharge current. Further, the control unit can more appropriately limit the supply power.

The state information may include the remaining capacity of the battery pack. The battery pack may also perform a protective action in response to the remaining capacity being below the first capacity threshold. The control unit may be configured to change the control parameter of the motor related to the supply power so as to limit the supply power in response to the remaining capacity being lower than a second capacity threshold larger than the first capacity threshold.

When the remaining capacity of the battery pack is lower than a second capacity threshold larger than the first capacity threshold, a control parameter of the motor related to the supplied power is changed. Thereby, the speed of decrease in the remaining capacity of the battery pack becomes slow. As a result, the execution of the protective function operation by the battery pack is suppressed, and the motor can continue to receive the supply power from the battery pack.

In addition, the state information may include a battery temperature of the battery pack. The battery pack may also perform a protective action in response to the battery temperature exceeding the first temperature threshold. The control unit may change the control parameter related to the supply power so as to limit the supply power in response to the battery temperature exceeding a second temperature threshold smaller than the first temperature threshold.

When the battery temperature exceeds a second temperature threshold value smaller than the first temperature threshold value, a control parameter related to the supplied power of the motor is changed. Thereby, the temperature rise of the battery pack is suppressed. As a result, the execution of the protection operation by the battery pack is suppressed, and the motor can continue to receive the supply power from the battery pack.

The control unit may execute PWM control, which is pulse width modulation of the motor. The control parameter may also include a duty ratio in the PWM control.

By changing the duty ratio in the PWM control, the value of the current flowing to the motor can be changed, and the supply power to the motor can be changed. Further, by reducing the duty ratio to suppress the supply of electric power, it is possible to suppress the execution of the protection operation by the battery pack.

The control unit may acquire the state information from before the motor is driven, and may change the control parameter based on the state information from before the motor is driven.

When the battery pack is attached to the electric working machine, the electric working machine acquires the state information from the battery pack before the motor is driven, and changes the control parameter based on the acquired state information. Thus, the motor can be started after the control parameter is set so that the battery pack does not perform the protection operation. Further, it is possible to prevent the battery pack from performing a protection operation to stop the motor immediately after the motor is started.

The electric working machine may further include a main power switch for supplying power to the control unit. The control unit may start requesting the state information from the battery pack at a time after the main power switch is turned on and before the motor is driven.

After the main power switch is turned on, communication between the electric working machine and the battery pack is started. Therefore, power consumption can be suppressed as compared with a case where communication is started only by mounting the battery pack to the electric working machine. Further, the state information is requested from the battery pack from a point before the motor is driven. Therefore, the control parameter can be changed before the motor is driven, and the motor can be started within a range of power consumption in which the battery pack does not perform the protection operation.

The control unit may acquire the state information transmitted from the battery pack by serial communication. The frequency of serial communication when current flows from the battery pack to the motor may be higher than the frequency of serial communication when current does not flow from the battery pack to the motor.

When no current flows from the battery pack to the motor, the state of the battery pack is less likely to change than when a current flows from the battery pack to the motor. Therefore, by suppressing the frequency of serial communication when no current flows from the battery pack to the motor, the processing load of the electric working machine can be suppressed.

Further, the control unit may set an upper current limit value for the discharge current flowing from the battery pack to the motor based on the acquired state information, and control the value of the discharge current to be equal to or less than the set upper current limit value.

The current upper limit value of the discharge current is set, and the driving of the motor is controlled so that the value of the discharge current is equal to or less than the set current upper limit value. In this way, by lowering the current upper limit value before the battery pack performs the protection operation, the motor can be continuously driven within a range of power consumption in which the battery pack does not perform the protection operation.

The present disclosure also includes the following items.

[ item A-1]

One aspect of the present disclosure is an electric working machine including a motor, an acquisition unit, and a control unit. The motor receives power supply from the battery pack and rotates. The acquisition unit acquires state information relating to a discharge state of the battery pack. The control unit changes a control parameter of the motor related to the power supplied from the battery pack to the motor before the protection function of the battery pack is activated, based on the state information acquired by the acquisition unit.

According to an aspect of the present disclosure, state information related to a discharge state of a battery pack is acquired by an electric working machine. The protection function operates when the battery pack becomes in an overcurrent state, for example. Therefore, the electric working machine changes the control parameter of the motor related to the supplied power before the protection function of the battery pack operates based on the acquired state information. Thus, the electric working machine can continue to receive the supply power changed so as to suppress the operation of the protection function of the battery pack. Further, since the condition under which the protection function of the battery pack operates is not changed, the protection function operates when the battery pack should be protected. This makes it possible to improve the convenience of the user while operating the protection function of the battery pack when protection is to be performed.

[ item A-2]

The control unit may change the control parameter so as to limit the supply power based on the state information.

The control unit changes the control parameter so as to limit the supply power, thereby limiting the supply power before the protection function of the battery pack is activated. As a result, the user can continue to use the electric working machine while the protection function of the battery pack is not operating.

[ item A-3]

The status information may also contain information relating to the precursor of the protective function action.

Since the state information includes information on a sign of the operation of the protection function, the electric working machine can recognize the sign of the operation of the protection function of the battery pack before the operation of the protection function. Further, the electric working machine is capable of changing the control parameter so that the protection function does not operate before the protection function operates.

[ item A-4]

The control parameter may include a discharge current supplied from the battery pack to the motor. The control unit may limit the discharge current based on the state information.

The control unit limits the discharge current, thereby limiting the supply power before the protection function of the battery pack is activated. As a result, the user can continue to use the electric working machine while the protection function of the battery pack is not operating.

[ item A-5]

The state information may include a count value obtained by adding up an addition value according to the magnitude of the discharge current supplied from the battery pack to the motor. The protection function of the battery pack may be operated when the count value exceeds the first threshold value. The control unit may change the control parameter when the count value exceeds a second threshold value smaller than the first threshold value.

When the count value exceeds a second threshold value smaller than the first threshold value, a control parameter relating to the supply power of the motor is changed. This suppresses the increase in the count value. As a result, the operation of the protection function of the battery pack is suppressed, and the motor can continue to receive power supply from the battery pack.

[ item A-6]

The state information may include mapping information indicating a correspondence relationship between the magnitude of the discharge current and the addition value. The control unit may set the second threshold value based on the magnitude of the detected discharge current and the acquired map information.

By including the mapping information in the state information, the control section can change the second threshold value in response to the magnitude of the discharge current. Further, the control unit can appropriately limit the supply power in response to the magnitude of the discharge current.

[ item A-7]

The state information may also include battery temperature of the battery pack and mapping information according to the different battery temperatures. The control unit may set the second threshold value based on the detected magnitude of the discharge current, the acquired battery temperature, and the acquired map information.

By including the map information corresponding to the different battery temperatures in the state information, the control section can change the second threshold value in response to the battery temperature and the magnitude of the discharge current. Further, the control unit can more appropriately limit the supply power.

[ item A-8]

The state information may also include the remaining capacity of the battery pack. The protection function of the battery pack may be operated when the remaining capacity is lower than the first capacity threshold. Further, the control unit may change the control parameter when the remaining capacity is lower than a second capacity threshold larger than the first capacity threshold.

When the remaining capacity of the battery pack is lower than a second capacity threshold larger than the first capacity threshold, a control parameter of the motor related to the supplied power is changed. This slows down the rate of decrease in the remaining capacity of the battery pack. As a result, the operation of the protection function of the battery pack is suppressed, and the motor can continue to receive the supply of electric power from the battery pack for a longer period of time.

[ item A-9]

The status information may also include a battery temperature of the battery pack. The protection function of the battery pack may be operated when the battery temperature exceeds the first temperature threshold. The control unit may change the control parameter when the battery temperature exceeds a second temperature threshold smaller than the first temperature threshold.

When the battery temperature exceeds a second temperature threshold value smaller than the first temperature threshold value, a control parameter related to the supplied power of the motor is changed. Thereby, the temperature rise of the battery pack is suppressed. As a result, the operation of the protection function of the battery pack is suppressed, and the motor can continue to receive the supply of electric power from the battery pack for a longer period of time.

[ item A-10]

The control unit may perform Pulse Width Modulation (PWM) control of the current flowing to the motor. The control parameter may also include a duty ratio in the PWM control.

By changing the duty ratio in the PWM control, the value of the current flowing to the motor can be changed, and the power supplied to the motor can be changed. Further, by reducing the duty ratio to suppress the supply power, the operation of the protection function of the battery pack can be suppressed.

[ item A-11]

The acquisition unit may acquire the state information from before the motor is driven. The control unit may change the control parameter based on the state information from before the motor is driven.

The state information is acquired from before the motor is driven, and the control parameter is changed based on the acquired state information. Thus, when the motor is temporarily stopped and restarted, the motor is not restarted by returning the control parameter from the value before the temporary stop to the initial value. This makes it possible to restart the motor within a range of power consumption in which the protection function of the battery pack does not operate.

[ item A-12]

The electric working machine may further include a main power switch for supplying power to the control unit. The control unit may start requesting the state information from the battery pack at a time after the main power switch is turned on and before the motor is driven.

After the main power switch is turned on, communication between the electric working machine and the battery pack is started. Therefore, power consumption can be suppressed as compared with a case where communication is started only by mounting the battery pack to the electric working machine. Further, the state information is requested from the battery pack from a point before the motor is driven. Therefore, before the motor is driven, the control parameter can be changed so that the motor can be driven within the range of the supplied power in which the protection function of the battery pack does not operate.

[ item A-13]

The acquisition unit may acquire the state information transmitted from the battery pack by serial communication. The frequency of serial communication when current flows from the battery pack to the motor may be higher than the frequency of serial communication when current does not flow from the battery pack to the motor.

When no current flows from the battery pack to the motor, the state of the battery pack is less likely to change than when a current flows from the battery pack to the motor. Therefore, by suppressing the frequency of serial communication when no current flows from the battery pack to the motor, the processing load of the electric working machine can be suppressed.

[ item A-14]

The electric working machine may further include a setting unit configured to set an upper limit value of a discharge current to be supplied from the battery pack to the motor, based on the state information acquired by the acquisition unit. The control unit may control the value of the discharge current to be equal to or less than the upper limit of the current set by the setting unit.

The current upper limit value of the discharge current is set, and the value of the discharge current is controlled to be less than or equal to the set current upper limit value. In this way, by lowering the current upper limit value before the protection function of the battery pack operates, the driving of the motor 50 can be continued within the range of the supplied power in which the protection function of the battery pack does not operate.

Drawings

Fig. 1 is a perspective view showing an external appearance of a working machine according to a first embodiment.

Fig. 2 is a block diagram showing a configuration of a motor control system according to the first embodiment.

Fig. 3 is a flowchart showing a main process executed by the control circuit of the working machine according to the first embodiment.

Fig. 4 is a flowchart showing a battery state process executed by the control circuit of the working machine according to the first embodiment.

Fig. 5 is a flowchart showing a motor control process executed by the control circuit of the working machine according to the first embodiment.

Fig. 6 is a flowchart showing a motor driving process executed by the control circuit of the working machine according to the first embodiment.

Fig. 7 is a flowchart showing a current upper limit setting process executed by the control circuit of the working machine according to the first embodiment.

Fig. 8 is a diagram schematically showing a data flow between the battery pack and the work machine according to the first embodiment.

Fig. 9 is a diagram showing the storage ratio transmitted from the battery pack to the work machine according to the first embodiment.

Fig. 10 is a timing chart of the motor load, the current upper limit value, the discharge current, the rotation speed, the trigger switch, and the guard count value according to the first embodiment.

Fig. 11 is a flowchart showing history processing executed by the battery control circuit according to the first embodiment.

Fig. 12 is a diagram showing a storage area for storing the number of times the charger is attached to the battery pack according to the first embodiment.

Fig. 13 is a diagram showing a storage area of the number of times the storage tool according to the first embodiment is attached to the battery pack.

Fig. 14 is a flowchart showing a motor driving process executed by the control circuit of the working machine according to the second embodiment.

Fig. 15 is a flowchart showing a protection count process executed by the control circuit of the working machine according to the second embodiment.

Fig. 16 is a flowchart showing a duty upper limit value setting process executed by the control circuit of the working machine according to the second embodiment.

Fig. 17 is a diagram schematically showing a data flow between the battery pack and the work machine according to the second embodiment.

Fig. 18 is a flowchart showing a current upper limit value setting process executed by the control circuit of the working machine according to the third embodiment.

Fig. 19 is a count map showing a correspondence relationship between the discharge current value and the added value.

Fig. 20 is a diagram schematically showing a data flow between the battery pack and the work machine according to the third embodiment.

Fig. 21 is a flowchart showing a battery communication process executed by the control circuit of the working machine according to the fourth embodiment.

Fig. 22 is a flowchart showing a protection count process executed by the control circuit of the working machine according to the fourth embodiment.

Fig. 23 is a flowchart showing a protection count value calculation process executed by the control circuit of the working machine according to the fourth embodiment.

Fig. 24 is a flowchart showing a current upper limit value setting process according to the fourth embodiment.

Fig. 25 is a flowchart showing another example of the current upper limit value setting process according to the fourth embodiment.

Fig. 26 is a count map transmitted from the battery pack to the working machine according to the fourth embodiment.

Fig. 27 is a diagram showing a change in the limit current value with respect to the protection count value according to the fourth embodiment.

Fig. 28 is a diagram schematically showing a data flow between the battery pack and the work machine according to the fourth embodiment.

Fig. 29 is a flowchart showing a protection count stop process executed by the control circuit of the working machine according to the fifth embodiment.

Fig. 30 is a timing chart of a motor load, a discharge current, a guard count value, and a trigger switch according to the fifth embodiment.

Description of the reference numerals

1 working machine, 2 main pipe, 3 control unit, 4 drive unit, 5 cover, 6 handle, 7 right handle, 8 left handle, 9 positive and negative change-over switch, 10 unlock button, 11 trigger, 12 trigger switch, 13 control wiring pipe, 16 motor shell, 17 cutting blade, 21 rear end shell, 22 battery pack, 23 speed change dial, 24 main switch, 25 display part, 28 battery voltage detection part, 30 controller, 32 drive circuit, 34 gate circuit, 36 control circuit, 38 voltage stabilizer, 41 positive terminal, 42 negative terminal, 43 ES terminal, 44 serial terminal, 50 motor, 52 rotation sensor, 54 current detection part, 56 temperature detection part, 60 battery, 61 battery positive terminal, 62 battery negative terminal, 63 battery ES terminal, 64 … battery serial terminal, 65 … battery control circuit, 66 … battery.

Detailed Description

Hereinafter, a mode for carrying out the present disclosure will be described with reference to the drawings.

(first embodiment)

< 1-1. integral Structure >

As shown in fig. 1, in the present exemplary embodiment, a case where the electric working machine of the present disclosure is applied to a lawn mower will be described. The work machine system of the present exemplary embodiment includes work machine 1 and battery pack 22. The working machine 1 is a lawnmower including a main pipe 2, a control unit 3, a drive unit 4, a cover 5, and a handle 6. The main pipe 2 is formed in an elongated hollow rod shape. The control unit 3 is provided on the rear end side of the main pipe 2. The drive unit 4 and the cover 5 are provided on the front end side of the main pipe 2.

The drive unit 4 includes a motor housing 16 and a cutting blade 17. The cutting blade 17 is a disk-shaped blade for cutting objects to be cut such as weeds and trees, and is configured to be attachable to and detachable from the motor case 16. The cover 5 is provided to prevent grass or the like cut off by the cutter blade 17 from flying toward the user of the work machine 1.

A motor 50 that generates a rotational force for rotating the cutting blade 17 is mounted inside the motor housing 16. The rotational force generated by the driving of the motor 50 is transmitted to the rotational shaft on which the cutting blade 17 is mounted via the speed reduction mechanism. When the cutter blade 17 is rotated by the rotational force of the motor 50, the user can cut the object by bringing the outer peripheral portion of the cutter blade 17 into contact with the object.

The handle 6 is formed in a U shape and connected to the main pipe 2 near a middle position in the longitudinal direction of the main pipe 2. A right grip 7 to be held by a user with a right hand is provided on a first end side of the handle 6, and a left grip 8 to be held by a user with a left hand is provided on a second end side of the handle 6.

A forward/reverse switch 9, an unlock button 10, and a trigger 11 are provided on the distal end side of the right grip 7. The forward/reverse switch 9 switches the rotation direction of the motor 50, i.e., the rotation direction of the cutting blade 17, to either forward or reverse rotation. The normal rotation is a rotation direction set when grass or the like is cut off, and the reverse rotation is a rotation direction set when grass or the like wound around the cutting blade 17 is removed.

The trigger 11 is an operation member operated by a user to instruct the rotation or stop of the cutting blade 17. A trigger switch 12 that operates in conjunction with the trigger 11 is disposed inside the right grip 7. The trigger switch 12 is turned on when the trigger 11 is operated and turned off when the trigger 11 is not operated, and outputs a trigger signal TS indicating the on state or the off state. In the present embodiment, the trigger 11 corresponds to an example of the operation portion.

The unlock button 10 is a button for preventing or suppressing malfunction of the cutting blade 17. In a state where the unlock button 10 is not pressed, the unlock button 10 mechanically engages with the trigger 11. Thereby, the movement of the trigger 11 is restricted, and the trigger switch 12 is prevented or suppressed from being turned on. When the unlock button 10 is pressed, the engagement with the trigger 11 by the unlock button 10 is released.

A control wiring duct 13 is provided between the lower end of the right handle 7 and the front end of the control unit 3. The control wiring pipe 13 is formed into a hollow rod shape, and a control wire harness is disposed inside the control wiring pipe. The control harness is a wire for electrically connecting the trigger switch 12 and the forward/reverse changeover switch 9 to the control unit 3.

The control unit 3 is constituted by a rear-end case 21 and a battery pack 22.

A shift dial 23 and a main switch 24 are provided on the front end side of the rear housing 21 in a state that can be operated by a user. The shift dial 23 is provided for the user to variably set the rotation speed of the motor 50. Main switch 24 is a switch for starting power supply from battery 60 to each part, thereby bringing work implement 1 into a usable state. When the main switch 24 is turned on, a discharge path from the battery 60 to the motor 50 is formed, and when the main switch 24 is turned off, the discharge path from the battery 60 to the motor 50 is cut off. In the present embodiment, the main switch 24 corresponds to an example of a main power switch.

Further, a display unit 25 is provided on the front end side of the rear end housing 21 so as to be visually recognizable by the user. The display unit 25 is provided to inform the user of the operating state, abnormality, and the like, and includes a display lamp, a remaining capacity display lamp, a reverse display lamp, and the like. The indicator lamp is turned on when the main switch 24 is turned on and power is supplied to each part of the work machine 1. The remaining capacity display lamp displays the remaining capacity of the battery 60. The reverse indicator light indicates that the motor 50 is in reverse. The remaining capacity is the amount of electricity remaining in the battery 60.

A controller 30 described later is disposed inside the rear end housing 21. The controller 30 mainly performs drive control of the motor 50. The controller 30 controls the rotation speed of the motor 50 by controlling the energization to the motor 50.

The battery pack 22 is configured to be attachable to and detachable from the rear end portion of the rear end case 21.

As shown in fig. 2, the battery pack 22 includes a battery 60, a battery control circuit 65, a battery positive terminal 61, a battery negative terminal 62, a battery ES terminal 63, and a battery serial terminal 64. The battery 60 is configured by connecting a plurality of battery cells in series. The battery 60 is a rechargeable power supply for supplying electric power to each part in the rear case 21 and the motor 50. As an example, the battery 60 is provided with a lithium ion 2-time battery. The rated voltage of the battery 60 may be 64V, for example.

< 1-2. Structure of motor control system >

Next, a control system of the motor 50 including the battery control circuit 65 and the controller 30 will be described with reference to fig. 2.

The battery control circuit 65 includes a CPU65a, a ROM65b, a RAM65c, a memory 65d such as a flash memory, and I/O.

The battery positive terminal 61 is connected to the positive side of the battery 60. The battery negative terminal 62 is connected to the negative side of the battery 60. The battery ES terminal 63 is connected to the battery control circuit 65 via a first battery connection line 68. The battery ES terminal 63 is a terminal that outputs a discharge enable signal or a discharge disable signal from the battery pack 22. ES is an alternative abbreviation for error stop.

The battery serial terminal 64 is connected to the battery control circuit 65 via a second battery connection line 69. The battery serial terminal 64 is a terminal for outputting a plurality of pieces of battery information by serial communication. The plurality of battery information includes state information related to the discharge state of the battery pack 22. The status information includes a protection count value, a count threshold value, a battery temperature, a remaining capacity of the battery 60, and the like, which will be described later. Further, the state information may include count map information, an addition threshold, a subtraction threshold, and the like, which will be described later.

The battery pack 22 includes a cell voltage detection unit, a cell temperature detection unit, and a battery current detection unit, which are not shown. The cell voltage detection unit detects the voltage value of each cell of the battery 60 and outputs a detection signal to the battery control circuit 65. The cell temperature detector is composed of a thermistor or the like, and detects the temperature of at least one cell and outputs a detection signal to the battery control circuit 65. The battery current detection unit detects a discharge current flowing in the battery 60 at the time of discharge, and outputs a detection signal to the battery control circuit 65.

The controller 30 includes a positive terminal 41, a negative terminal 42, an ES terminal 43, and a serial terminal 44. The controller 30 further includes a drive circuit 32, a gate circuit 34, a control circuit 36, and a regulator 38.

The positive terminal 41 is connected to a battery positive terminal 61 of the battery pack 22. The negative terminal 42 is connected to a battery negative terminal 62 of the battery pack 22. The ES terminal 43 is a terminal connected to the battery ES terminal of the battery pack 22, and is a terminal to which a discharge enable signal or a discharge disable signal transmitted from the battery pack 22 is input. The serial terminal 44 is a terminal to which battery information transmitted from the battery pack 22 is input by serial communication.

The ES terminal 43 is connected to the control circuit 36 via a first connection line 48, and the serial terminal 44 is connected to the control circuit 36 via a second connection line 49.

The drive circuit 32 is a circuit that receives power supply from the battery 60 and causes current to flow to each corresponding winding of the motor 50. The motor 50 is a 3-phase brushless motor. The drive circuit 32 is a 3-phase full bridge circuit including high-side switching elements Q1 to Q3 and low-side switching elements Q4 to Q6. The switching elements Q1 to Q6 include, for example, MOSFETs, but may include elements other than MOSFETs.

The gate circuit 34 turns on or off the switching elements Q1 to Q6 of the drive circuit 32 in accordance with a control signal output from the control circuit 36, and causes currents to flow sequentially to the phase windings of the motor 50, thereby rotating the motor 50. When all of the switching elements Q1 to Q6 are turned off, the motor 50 is in an idle state. When the switching elements Q1 to Q3 are all turned off and the switching elements Q4 to Q6 are all turned on, the motor 50 is in a state where so-called short brake is applied.

When the main switch 24 is turned on, the regulator 38 receives power supply from the battery 60 and generates a constant power supply voltage Vcc (for example, 5V dc) necessary for operating the control circuit 36.

The control circuit 36 includes a CPU36a, a ROM36b, a RAM36c, I/O, and the like. The control circuit 36 is connected to an ES terminal 43, a serial terminal 44, a trigger switch 12, a main switch 24, a display unit 25, and a battery voltage detection unit 28. Further, although not shown, the forward/reverse selector switch 9 and the shift dial 23 are also connected to the control circuit 36.

The battery voltage detection unit 28 detects a voltage between the positive terminal 41 and the negative terminal 42, that is, a value of a voltage of the battery 60 (hereinafter, referred to as a battery voltage), and outputs a detection signal to the control circuit 36.

In the controller 30, a current detection unit 54 that detects a discharge current value supplied to the motor 50 is provided in an energization path from the drive circuit 32 to the negative electrode of the battery 60. Further, a rotation sensor 52 that detects a rotational position of a rotor included in the motor 50 is provided in the vicinity of the motor 50. The rotation sensor 52 is, for example, a hall sensor, an optical encoder, a magnetic encoder, or the like. Further, a temperature detection unit 56 is provided in the vicinity of the switching element of the drive circuit 32, and the temperature detection unit 56 is constituted by a thermistor or the like that detects the temperature of the switching element. Further, detection signals from the current detection unit 54, the rotation sensor 52, and the temperature detection unit 56 are also input to the control circuit 36. The control circuit 36 calculates the rotational position and the rotational speed of the motor 50 based on the detection signal from the rotation sensor 52.

The control circuit 36 operates by receiving power supply from the regulator 38. The control circuit 36 executes various processes including a main process described later based on various detection signals and operation states of various switches. In the present embodiment, the control circuit 36 corresponds to an example of a control unit.

< 1-3. processing in working machine >

< 1-3-1. Main processing >

Next, the main process executed by control circuit 36 of work machine 1 will be described with reference to the flowchart of fig. 3.

First, in S10, the control circuit 36 determines whether or not the time base has elapsed. The control circuit 36 stands by when the time base has not elapsed, and proceeds to the process of S20 when the time base has elapsed. The time base corresponds to the control period of the control circuit 36.

In S20, the control circuit 36 executes the operation detection processing of the trigger switch 12. In detail, the control circuit 36 detects whether the trigger switch 12 is on or off based on a signal from the trigger switch 12.

Next, in S30, the control circuit 36 executes battery state processing based on the information output from the battery pack 22. The details of the battery state processing will be described later.

Next, in S40, the control circuit 36 executes the AD conversion process. Specifically, the control circuit 36 AD-converts the detection signals input from the battery voltage detection unit 28, the current detection unit 54, and the temperature detection unit 56. Thereby, the control circuit 36 acquires the value of the discharge current supplied to the motor 50, the voltage value of the battery 60, and the temperature of the switching element.

Next, in S50, the control circuit 36 executes abnormality detection processing. More specifically, the control circuit 36 compares the discharge current value, the voltage value, and the temperature acquired in S40 with respective threshold values to detect abnormalities such as overcurrent, a drop in battery voltage, and a high-temperature state of the switching element.

Next, in S60, the control circuit 36 executes the motor control process based on the operation state of the trigger switch 12, the battery state, and the detection result of the abnormality. The details of the motor control process will be described later.

Next, in S70, the control circuit 36 executes display processing. Specifically, the control circuit 36 displays the operating state of the motor 50, the remaining capacity of the battery 60, the detected abnormality, and the like, and notifies the user of the display. This process is ended.

< 1-3-2. Battery State handling >

Next, details of the battery state processing executed by the control circuit 36 in S30 will be described with reference to the flowchart of fig. 4.

First, in S100, the control circuit 36 executes a battery communication process. Specifically, when detecting that battery pack 22 is mounted on work implement 1, control circuit 36 transmits the model number of work implement 1 via serial terminal 44 by initial communication with battery pack 22 and receives the model number of battery pack 22. Further, the control circuit 36 may also receive count map information through initial communication with the battery pack 22.

Further, the control circuit 36 transmits an information request signal to the battery control circuit 65 via the serial terminal 44 at a prescribed cycle, and receives battery information from the battery control circuit 65 as a response to the information request signal. Here, the period of transmitting the information request signal is set longer when no discharge current flows from battery pack 22 to work implement 1 than when a discharge current flows from battery pack 22 to work implement 1. That is, the frequency of serial communication is set lower when no current flows from battery pack 22 to work implement 1 than when a discharge current flows.

At a time point after the main switch 24 is turned on and before the motor 50 is driven, the control circuit 36 transmits an information request signal to the battery control circuit 65 to start requesting battery information from the battery pack 22.

Next, in S110, the control circuit 36 sets permission or prohibition of discharge from the battery pack 22. Specifically, the control circuit 36 sets the discharge enable flag when receiving the discharge enable signal from the battery pack 22. In addition, the control circuit 36 clears the discharge permission flag when receiving the discharge prohibition signal from the battery pack 22. This process is ended.

< 1-3-4. Motor control processing >

Next, details of the motor control process executed by the control circuit 36 in S60 will be described with reference to the flowchart of fig. 5.

First, in S300, the control circuit 36 determines whether or not the trigger switch 12 is turned on. If the control circuit 36 determines that the trigger switch 12 is on, the process proceeds to S310, and if the control circuit 36 determines that the trigger switch 12 is off, the process proceeds to S340.

In S310, the control circuit 36 determines whether an abnormality is detected in S50. If it is determined that no abnormality is detected, the control circuit 36 proceeds to the process of S320. When determining that an abnormality is detected, the control circuit 36 proceeds to the process of S340.

In S320, the control circuit 36 determines whether or not the discharge enable flag is set. If it is determined that the discharge enable flag is set, the control circuit 36 proceeds to the process of S330, and if it is determined that the discharge enable flag is cleared, the control circuit proceeds to the process of S340.

In S330, the control circuit 36 receives the power supply from the battery 60, executes the motor driving process, and ends the present process. The details of the motor driving process will be described later.

On the other hand, in S340, the control circuit 36 determines whether or not to perform the braking control. Specifically, the control circuit 36 determines to execute the braking control in a case where the motor 50 is rotated and there is no influence on the controller 30 even if the motor 50 is caused to generate the braking force. In this case, the control circuit 36 sets the brake flag in S350, and ends the present process. Thereby, the supply of electric power from the battery 60 to the motor 50 is stopped, and short-circuit braking is performed.

On the other hand, the control circuit 36 determines not to perform the braking control when the motor 50 is not rotating or when the controller 30 is affected by the braking force generated by the motor 50 although the motor 50 is rotating. In this case, the control circuit 36 clears the brake flag in S360, and ends the present process. Thereby, the supply of electric power from the battery 60 to the motor 50 is stopped. When the motor 50 is rotated, idle operation or the like is performed.

< 1-3-5. Motor drive processing >

Next, details of the motor driving process executed by the control circuit 36 in S330 will be described with reference to the flowchart of fig. 6.

First, in S400, the control circuit 36 executes a rotation speed setting process of setting a target rotation speed of the motor 50. Specifically, the control circuit 36 sets the rotation direction of the motor 50 based on the setting of the forward/reverse changeover switch 9. Further, the control circuit 36 sets the target rotation speed of the motor 50 in the set rotation direction based on the setting of the shift dial 23.

Next, in S410, the control circuit 36 executes an upper limit value setting process of setting the current upper limit value of the discharge current. The current upper limit value is a value for controlling the discharge current. The control circuit 36 controls the value of the discharge current to be equal to or lower than the current upper limit value. The details of the upper limit setting process will be described later.

Next, in S420, the control circuit 36 performs a duty ratio calculation process in Pulse Width Modulation (PWM) control. The control circuit 36 PWM-controls the current flowing to the motor 50 using the calculated duty ratio. In S420, the control circuit 36 calculates the duty ratio in the PWM control in such a manner that the following conditions (1) and (2) are satisfied. The condition (1) is that the discharge current is equal to or less than the upper limit of the current set in S410. The condition (2) is that the rotation speed of the motor 50 converges to the target rotation speed set in S400. When both of the conditions (1) and (2) cannot be satisfied, the control circuit 36 preferentially satisfies the condition (1), and calculates the duty ratio so that the rotation speed of the motor 50 approaches the target rotation speed as close as possible when the condition (1) is satisfied.

Next, in S430, the control circuit 36 performs output processing of the duty ratio. Specifically, the control circuit 36 generates a control command based on the duty ratio calculated in S420, and outputs the generated control command to the gate circuit 34. This process is ended.

< 1-3-6. Current Upper Limit value setting Process

Next, details of the current upper limit value setting process executed by the control circuit 36 in S410 will be described with reference to the flowchart of fig. 7.

First, in S500, it is determined whether or not the guard count value acquired from the battery pack 22 is larger than the count threshold. The protection count value is a value obtained by integrating (i.e., accumulating) the addition value according to the magnitude of the discharge current of the battery 60 by the battery control circuit 65.

When the discharge current value is equal to or greater than the addition threshold value, the battery control circuit 65 adds the addition value to the guard count value. The battery control circuit 65 increases the addition value as the discharge current value increases. For example, when the addition threshold is 50A, the battery control circuit 65 does not add the guard count value when the discharge current value is less than 50A. The battery control circuit 65 adds the guard count value to the addition value "1" when the discharge current value is 50A, and adds the guard count value to the addition value "3" when the discharge current value is 70A. The battery control circuit 65 adds an addition value corresponding to the magnitude of the discharge current to the guard count value for each control cycle. Thus, the accumulated value of the addition values (i.e., the accumulated value) becomes the guard count value. Thus, the larger the discharge current value is, and the longer the discharge current having a magnitude equal to or larger than the addition threshold flows, the larger the guard count value becomes. Further, when the discharge current value is equal to or less than the subtraction threshold value, the battery control circuit 65 subtracts a predetermined value from the protection count value. The subtraction threshold is, for example, 5A.

If the overcurrent state (i.e., the overload state of battery 60) is reached in which a large current flows for a long time, battery 60 may deteriorate. Therefore, if the protection count value exceeds the protection threshold value, the battery control circuit 65 performs the protection operation. Specifically, the battery control circuit 65 sends a discharge prohibition signal to the control circuit 36. The count threshold used for the determination at S500 is a value smaller than the guard threshold, for example, a value of 50% to 70% of the guard threshold.

That is, in S500, the control circuit 36 determines whether or not a sign of the operation of the protection function of the battery pack 22 is detected before the operation of the protection function of the battery pack 22. In S500, when the protection count value is equal to or less than the count threshold, that is, when the sign of the operation of the protection function of the battery pack 22 is not detected, the control circuit 36 proceeds to the process of S510. In S500, if the protection count value is greater than the count threshold value, that is, if a sign of the operation of the protection function of the battery pack 22 is detected, the control circuit 36 proceeds to the process of S520.

In S510, the control circuit 36 sets a normal current value to the current upper limit value. The current value is usually a current value equal to or higher than the addition threshold.

On the other hand, in S520, the control circuit 36 sets a limit current value to the current upper limit value. The limit current value is a current value smaller than the addition threshold value. That is, the limit current value is a value that keeps the guard count value at a constant value or less.

Here, when the load of the motor 50 increases, the discharge current increases in order to converge the rotation speed of the motor 50 to the target rotation speed. Therefore, if the load of the motor 50 increases in a state where the guard count value exceeds the count threshold, the guard count value may reach the guard threshold, and the guard function of the battery pack 22 may operate. When the protection function of the battery pack 22 is activated, the discharge of the battery pack 22 is stopped, and the motor 50 is stopped without supplying electric power to the motor 50. Further, the user cannot continue the work, and the work efficiency is lowered.

Therefore, when the warning of the operation of the protection function of the battery pack 22 is detected, the control circuit 36 limits the discharge current value to a value smaller than the addition threshold. Thus, even if the load of the motor 50 increases, the protection count value does not increase, and therefore the protection function of the battery pack 22 does not operate. Therefore, the user may continue to use the work machine 1 even though the rotation speed of the motor 50 is lower than the target rotation speed by limiting the discharge current value.

Fig. 8 is a diagram showing an outline of a data flow between battery pack 22 and work implement 1 when the main process according to the present embodiment is executed. In the battery pack 22, a protection count value is calculated from the discharge current and the count map. The count map is a map indicating a correspondence relationship between the discharge current value and the addition value and the subtraction value (i.e., negative addition value) (see fig. 19 and 26). In the battery pack 22, the addition value or the subtraction value corresponding to the discharge current value in the count map is added at a predetermined cycle to calculate a guard count value.

Further, the calculated protection count value and the protection threshold value stored in the battery pack 22 are transmitted from the battery pack 22 to the work machine 1. In the work machine 1, the discharge current is limited using the received guard count value and the count threshold value smaller than the guard threshold value.

Instead of the guard count value, the storage ratio may be transmitted from the battery pack 22 to the work machine 1. As shown in fig. 9, the accumulation ratio is a ratio of the current guard count value to the guard threshold value when the guard threshold value is set to 100%. In this case, the count threshold is represented by a ratio (e.g., 80%) with respect to the protection threshold.

< 1-3-7 actions of work machine

Next, the operation of work implement 1 will be described with reference to the timing chart of fig. 10.

At time t0, when the trigger switch 12 is turned on, the discharge current starts to flow, and the rotation speed of the motor 50 starts to increase. Further, the motor load gradually increases from time t1 to time t5, and becomes zero at time t 5.

During the period from time t1 to time t2, the discharge current increases as the motor load increases. Further, at time t2, the discharge current value becomes equal to or greater than the addition threshold value, and the guard count value starts to increase.

At time t3, the discharge current reaches the current upper limit value. The current upper limit value at this time is a normal set value. The rotation speed of the motor 50 is maintained at the target rotation speed until time t3 after the target rotation speed is reached.

During the period from time t3 to time t4, the discharge current is suppressed to the current upper limit value during the increase in the motor load. Therefore, during the period from time t3 to time t4, the rotation speed of the motor 50 decreases. In this period, the discharge current value is equal to or greater than the addition threshold value, and therefore the guard count value increases.

Further, at time t4, when the guard count value exceeds the count threshold value, the current upper limit value is set as the limit current value. Thus, the discharge current is suppressed to be smaller than the addition threshold, and therefore, the increase of the guard count value is stopped. Therefore, the guard count value is maintained at a constant value during the period from the time t4 to the time t 7. In addition, since the discharge current value is limited to the limit current value smaller than the normal set value from time t4 to time t5, the rotation speed of the motor 50 further decreases.

At time t5, the load of motor 50 becomes zero. Accordingly, the discharge current becomes smaller than the current upper limit value, and the rotation speed of the motor 50 returns to the target rotation speed.

Further, at time t6, when the trigger switch 12 is turned off, the discharge current value becomes zero. That is, the discharge current does not flow. Thereafter, at time t7, the guard count value starts to decrease as the discharge current becomes non-flowing. Further, at time t8, the current upper limit value is set to the normal set value as the guard count value becomes lower than the count threshold value.

Here, at time t4, when the current upper limit value is kept constant at the normal set value, the guard count value is continuously increased to the guard threshold value. Further, when the guard count value reaches the guard threshold value, the guard function of the battery pack 22 is activated to stop the motor 50, and the user cannot continue the work. In contrast, in the present embodiment, the upper limit current value is suppressed to the limit current value at time t4, and the user can continue the operation until the trigger 11 is turned off.

< 1-4. processing in Battery pack >

< 1-4-1. History processing >

Next, the history processing executed by the battery control circuit 65 will be described with reference to the flowchart of fig. 11.

First, in S600, the battery control circuit 65 determines whether or not a charger or a working machine is mounted on the battery pack 22. When the charger or the working machine is not attached to the battery pack 22, the battery control circuit 65 repeatedly executes the process of S600 until the battery pack 22 is attached. When the charger or the working machine is attached to the battery pack 22, the battery control circuit 65 proceeds to the process of S610.

In S610, the battery control circuit 65 performs initial communication with a charger or a working machine (hereinafter, installation apparatus) installed in the battery pack 22, transmits the model number of the battery pack 22, and acquires the model number of the installation apparatus transmitted from the installation apparatus.

Next, in S620, the battery control circuit 65 determines whether the mounted device is detached from the battery pack 22. If the attached device is not detached, the battery control circuit 65 repeatedly executes the process of S620 until the attached device is detached. When the mounted device is detached from the battery pack 22, the battery control circuit 65 proceeds to the process of S630.

In S630, the battery control circuit 65 determines whether or not there is the model number of the mounted device acquired in S610 in the history database in the memory 65d of the battery pack 22. As shown in fig. 12 and 13, the history database includes a charger storage area for storing the number of times of mounting the charger and a work machine storage area for storing the number of times of mounting the work machine. The model of the charger and the number of times of installation of the charger of the model are associated and stored in the charger storage area. The model of the working machine and the number of times the working machine of that model is mounted are stored in the working machine storage area in a corresponding relationship.

In the case where the mounted apparatus is a charger, the battery control circuit 65 determines whether or not there is the model acquired in S610 in the charger storage area. In addition, in the case where the mounting apparatus is a working machine, the battery control circuit 65 determines whether or not the model acquired in S610 is in the working machine storage area.

The battery control circuit 65 proceeds to the process of S640 if the model number of the mounted device does not exist in the history database, and proceeds to the process of S660 if the model number of the mounted device exists in the history database.

In S640, the battery control circuit 65 determines whether or not there is a free space in the storage area corresponding to the history database. Specifically, in the case where the mounted device is a charger, the battery control circuit 65 determines whether or not there is a free space in the charger storage area. In addition, in the case where the mounting apparatus is a working machine, the battery control circuit 65 determines whether or not there is a free space in the working machine storage area. If the storage area corresponding to the history database has no free space, the battery control circuit 65 returns to the process of S600, and if the corresponding storage area has free space, the process proceeds to S650.

In S650, the battery control circuit 65 stores the model number of the mounting apparatus acquired in S610 in the corresponding storage area. Specifically, the battery control circuit 65 stores the acquired model in the free space of the charger storage area in the case where the installation apparatus is a charger. In addition, when the mounting apparatus is a work machine, the battery control circuit 65 stores the acquired model number in a free space of the work machine storage area.

Generally, the types of work machines are many in comparison with the types of chargers. Therefore, if the history database has only one storage area, the models of the work machines are sequentially stored in the storage area, and there is a possibility that the empty space for storing the new model of the charger is lost. In contrast, since the history database includes the charger storage area and the work area storage area, even if the types of the work machines attached to the battery pack 22 increase, an area for storing a new type of the charger can be secured.

Next, in S660, the battery control circuit 65 increases the number of times of installation corresponding to the model acquired in S610. Specifically, the battery control circuit 65 increases the number of times of installation corresponding to the model acquired in S610 among the models stored in the charging device area by "1" in the case where the installation device is a charger. In addition, in the case where the mounting apparatus is a working machine, the battery control circuit 65 increases the number of times of mounting corresponding to the model acquired in S610 among the models stored in the working machine storage area by "1". This process is ended.

In the history processing, when the mounting apparatus is mounted on the battery pack 22, the model number of the mounting apparatus is acquired, and when the mounting apparatus is detached from the battery pack 22, writing of the model number to the memory 65d and updating of the number of times of mounting in the memory 65d are performed. When the mounted device is mounted on the battery pack 22, the battery control circuit 65 executes processing such as charging control, discharging control, and communication with the mounted device, and therefore the processing load increases, and there is a case where there is no margin for writing into the memory 65d or updating the memory 65 d. Therefore, the battery control circuit 65 keeps writing into the memory 65d and updating the memory 65d until the mounted device is detached from the battery pack 22, that is, until a margin in time can be achieved. Thus, the battery control circuit 65 can reliably execute writing into the memory 65d and updating of the memory 65 d.

< 1-5. Effect >

According to the first embodiment described above, the following effects can be obtained.

(1) The control circuit 36 lowers the current upper limit value of the discharge current before the protection function of the battery pack 22 operates, based on the acquired state information of the battery pack 22. Thus, since the discharge current is limited, even when the load of work implement 1 is relatively high, the user can continue to use work implement 1 within the range of power consumption in which the protection function of battery pack 22 does not operate. In addition, the protection function operates when the protection count value exceeds the protection threshold value. That is, the protection function operates when the battery pack 22 should be protected. This enables the protection function of the battery pack 22 to be operated when protection is to be performed, thereby improving user convenience.

(2) The overcurrent state (i.e., the overload state) of the battery pack 22 can be determined based on the magnitude of the discharge current and the time during which the discharge current flows. Thus, the control circuit 36 can determine the overcurrent state of the battery pack 22 based on the protection count value obtained by adding up the addition value or the subtraction value according to the magnitude of the discharge current.

(3) When the guard count value exceeds the count threshold value smaller than the guard threshold value, the supply power supplied from the battery pack 22 to the motor 50 is reduced. Thus, the motor 50 can continue to receive power supply from the battery pack 22 within a range of power consumption in which the protection function of the battery pack 22 does not operate.

(4) When the protection count value exceeds the count threshold value, the current upper limit value of the discharge current is lowered. By lowering the current upper limit value, the discharge current value is lowered, and the power supply to the motor 50 is lowered. Further, the increase of the protection count value can be suppressed, and the operation of the protection function of the battery pack 22 can be suppressed.

(5) The guard count value, the addition threshold value, and the subtraction threshold value are acquired from before the motor 50 is driven, and the current upper limit value is changed based on these acquired values. Thus, when the motor 50 is temporarily stopped and restarted, the motor 50 is restarted without changing the current upper limit value from the set value before the temporary stop to the normal set value. This enables the motor 50 to be restarted within a range of power consumption in which the protection function of the battery pack 22 does not operate.

(6) Communication between the control circuit 36 and the battery control circuit 65 is started after the main switch 24 is turned on. Therefore, power consumption of battery 60 can be suppressed as compared with a case where communication is started only by attaching battery pack 22 to work implement 1. Further, the information request signal is transmitted from the control circuit 36 to the battery control circuit 65 from the time before the motor 50 is driven. Therefore, the driving of the motor 50 can be started within the range of the power consumption in which the protection function of the battery pack 22 does not operate.

(7) When no current flows from the battery pack 22 to the motor 50, the state of the battery pack 22 is less likely to change than when a current flows from the battery pack 22 to the motor 50. Therefore, when no current flows from the battery pack 22 to the motor 50, the frequency of serial communication is suppressed, whereby the processing load on the control circuit 36 and the battery control circuit 65 can be suppressed.

(8) The current upper limit value of the discharge current is set based on the guard count value, and the discharge current is controlled so as to be equal to or less than the set current upper limit value. Thus, since the current upper limit value is reduced before the protective function of the battery pack 22 is operated, the driving of the motor 50 can be continued within the range of the power consumption in which the protective function of the battery pack 22 is not operated.

(second embodiment)

< 2-1. different points from the first embodiment >

Since the basic configuration of the second embodiment is the same as that of the first embodiment, the description of the common configuration is omitted, and the description of the different points is mainly given. Note that the same reference numerals as those in the first embodiment denote the same components, and the foregoing description is referred to.

In the first embodiment described above, the battery control circuit 65 calculates the protection count value, and transmits the calculated protection count value and the count threshold value to the control circuit 36 of the work machine 1 as battery information. In contrast, the second embodiment differs from the first embodiment in that the control circuit 36 receives the count map information, the addition threshold value, and the subtraction threshold value from the battery pack 22 and calculates the protection count value using the received contents.

In the first embodiment, when a sign indicating that the protection function of the battery pack 22 is operating is detected, the control circuit 36 lowers the current upper limit value so that the protection count value does not exceed the protection threshold value. In contrast, in the second embodiment, when the warning of the operation of the protection function of the battery pack 22 is detected, the control circuit 36 lowers the duty upper limit value in the PWM control so that the protection count value does not exceed the protection threshold value. That is, in the first embodiment, the discharge current value is reduced by setting the current upper limit value to a value smaller than the normal value. In contrast, in the second embodiment, the discharge current value is reduced by setting the duty upper limit value to a value smaller than the normal value.

Specifically, the second embodiment differs from the first embodiment with respect to the motor driving process in S330 of the motor control process shown in fig. 5. In the first embodiment, the control circuit 36 executes the processing shown in the flowcharts shown in fig. 6 and 7 in the motor driving processing in S330. In contrast, in the second embodiment, the control circuit 36 executes the processing shown in the flowcharts of fig. 14 to 16 in the motor driving processing in S330.

< 2-2. processing in working machine >

< 2-2-1. Motor drive processing >

Next, details of the motor driving process executed by the control circuit 36 in S330 will be described with reference to the flowchart of fig. 14.

First, in S700, the control circuit 36 executes the same processing as S400 shown in fig. 6.

Next, in S710, the control circuit 36 executes protection count processing of calculating a protection count value. The details of the guard count process will be described later.

Next, in S720, the control circuit 36 executes a duty upper limit value setting process of setting an upper limit value of the duty in the PWM control. The details of the duty upper limit value setting process will be described later.

Next, in S730, the control circuit 36 performs the duty ratio calculation process in the PWM control. Specifically, the control circuit 36 calculates the duty ratio in such a manner that the conditions (3) and (4) are satisfied. The following condition (3) is that the duty ratio is equal to or less than the duty ratio upper limit value set in S720. The condition (4) is that the rotation speed of the motor 50 converges to the target rotation speed set in S700. When both of the conditions (3) and (4) cannot be satisfied, the control circuit 36 preferentially satisfies the condition (3), and calculates the duty ratio so that the rotation speed of the motor 50 approaches the target rotation speed as close as possible while the condition (4) is satisfied.

Next, in S740, the control circuit 36 executes the same processing as S430 shown in fig. 6. This process is ended.

< 2-2-2. protection count processing >

Next, details of the protection count process executed by the control circuit 36 in S710 will be described with reference to the flowchart of fig. 15.

First, in S800, the control circuit 36 determines whether or not the discharge current value detected by the current detection unit 54 is equal to or greater than an addition threshold value.

When the discharge current value is equal to or greater than the addition threshold value, the control circuit 36 proceeds to the process of S810, and when the discharge current value is smaller than the addition threshold value, the control circuit proceeds to the process of S830.

In S810, an addition value of a positive value corresponding to the magnitude of the discharge current is calculated using the received count map. As shown in fig. 19, the control circuit 36 calculates a larger addition value as the discharge current value is larger. For example, the control circuit 36 calculates an addition value "1" when the discharge current value is 50A, and calculates an addition value "3" when the discharge current value is 70A.

Next, in S820, the control circuit 36 adds the guard count value to the addition value calculated in S810 to update the guard count value, and ends the present process.

On the other hand, in S830, the control circuit 36 determines whether or not the discharge current value is equal to or less than the subtraction threshold. The subtraction threshold is a value smaller than the addition threshold, and is 5A, for example. When the discharge current value is equal to or less than the subtraction threshold, the control circuit 36 proceeds to the process of S840, and when the discharge current value is greater than the subtraction threshold, the control circuit ends the process.

In S840, the control circuit 36 calculates a subtraction value as a constant value from the received count map, and subtracts the calculated subtraction value from the protection count value to update the protection count value. This process is ended.

< 2-2-3 > duty ratio upper limit value setting process

Next, details of the duty upper limit value setting process executed by the control circuit 36 in S720 will be described with reference to the flowchart of fig. 16.

First, in S900, the control circuit 36 determines whether or not the guard count value is larger than the count threshold value. When the guard count value is equal to or less than the count threshold, the control circuit 36 proceeds to the process of S910, and when the guard count value is greater than the count threshold, the control circuit proceeds to the process of S920.

In S910, the control circuit 36 sets a normal duty to the duty upper limit value. The duty ratio is a duty ratio at which the discharge current value is equal to or higher than the addition threshold value, and is, for example, 100%.

On the other hand, in S920, the control circuit 36 sets a limit duty to the duty upper limit value. The limit duty is a duty in which the discharge current value is set to a value smaller than the addition threshold value, and is a value smaller than the normal duty. This process is ended.

Fig. 17 is a diagram showing an outline of a data flow between battery pack 22 and work implement 1 when the main process according to the present embodiment is executed. The battery pack 22 transmits the count map, the addition threshold, the subtraction threshold, and the protection threshold to the work machine 1. In work machine 1, the discharge current value, and the received count map, addition threshold value, and protection threshold value are used to calculate a protection count value. Further, in the work machine 1, the duty ratio is limited using the calculated guard count value and the count threshold calculated from the received guard threshold.

< 2-3. Effect >

According to the second embodiment described above, the effects (1) to (3), (6), and (7) of the first embodiment are exhibited, and the following effect (9) is exhibited.

(9) When the guard count value exceeds the count threshold value, the duty upper limit value is lowered. By lowering the duty upper limit value, the discharge current is reduced, and the electric power supplied from the battery pack 22 to the motor 50 is reduced. Further, the increase of the protection count value can be suppressed, and the operation of the protection function of the battery pack 22 can be suppressed.

(third embodiment)

< 3-1. different points from the first embodiment >

Since the basic configuration of the third embodiment is the same as that of the first embodiment, the description of the common configuration is omitted, and the description of the different points is mainly given. Note that the same reference numerals as those in the first embodiment denote the same structures, and the above description is referred to.

In the first embodiment, the count threshold is a fixed value. In contrast, the third embodiment is different from the first embodiment in that the count threshold value is a variable value set based on the state information received by the control circuit 36 from the battery pack 22.

Specifically, in the third embodiment, the current upper limit value setting process in S410 of the motor driving process shown in fig. 6 is different from that in the first embodiment. In the first embodiment, the control circuit 36 executes the processing shown in the flowchart of fig. 7 in the current upper limit value setting processing in S410. In contrast, in the third embodiment, the control circuit 36 executes the processing shown in the flowchart of fig. 18 in the current upper limit value setting processing in S410.

< 3-2. Current Upper Limit value setting Process >

Next, in the present embodiment, details of the current upper limit value setting process executed by the control circuit 360 in S410 will be described with reference to a flowchart shown in fig. 18.

First, in S505, the control circuit 36 sets a count threshold. Specifically, the control circuit 36 sets the count threshold value based on the magnitude of the discharge current detected by the current detection unit 54 and the count map information received from the battery pack 22. As shown in fig. 19, the count map information indicates the correspondence between the magnitude of the discharge current and the addition value and the subtraction value. Here, the addition value includes a positive value and zero, and the subtraction value includes a negative value. The larger the discharge current value is, the larger the addition value becomes, and the subtraction value becomes constant.

The control circuit 36 acquires an addition value corresponding to the magnitude of the detected discharge current using the count map information. Further, the control circuit 36 calculates a rate of increase of the guard count value when the acquired addition value is added to the guard count value, and sets the count threshold value based on the calculated rate of increase. For example, the control circuit 36 sets the count threshold to a relatively small value so as to immediately limit the discharge current when the rate of rise is higher than the set rate of rise threshold, and sets the count threshold to a relatively large value when the rate of rise is equal to or lower than the rate of rise threshold.

Even if the same magnitude of discharge current flows, the battery 60 is more likely to deteriorate at a relatively high battery temperature than at a relatively low battery temperature. Thus, the count map information can be classified according to different battery temperatures. For example, as shown in fig. 19, the count map information may be classified into a case where the battery temperature is equal to or higher than Th ℃ and a case where the battery temperature is lower than Th ℃. In this case, the control circuit 36 may set the count threshold value based on the detected magnitude of the discharge current, the battery temperature received from the battery pack 22, and the count map information.

Further, even if the same magnitude of discharge current flows, when the remaining capacity of the battery 60 is relatively small, the battery 60 is more likely to deteriorate than when the remaining capacity is relatively large. Thus, the count map information can be classified into different battery temperatures and different remaining capacities. In this case, the control circuit 36 may set the count threshold value based on the detected magnitude of the discharge current and the battery temperature, the remaining capacity, and the count map information received from the battery pack 22.

Next, in the processing of S515 to S535, the control circuit 36 executes the same processing as S500 to S520 shown in fig. 7.

Fig. 20 is a diagram showing an outline of a data flow between battery pack 22 and work implement 1 when the main process according to the present embodiment is executed. In the battery pack 22, a protection count value is calculated from the discharge current value and the count map. The count map may also be a map corresponding to the battery temperature and/or the remaining capacity.

Further, the calculated guard count value and the count map are transmitted from the battery pack 22 to the work machine 1. In work machine 1, the count threshold is calculated from the received guard count value and the count map. Further, in the work machine 1, the discharge current is limited using the received guard count value and the calculated count threshold value.

< 3-3. Effect >

According to the third embodiment described above, the effects (1) to (8) of the first embodiment are exhibited, and the following effect (10) is exhibited.

(10) The control circuit 36 can change the count threshold value according to the magnitude of the discharge current by using the count map information. Further, the control circuit 36 can appropriately limit the supply power according to the magnitude of the discharge current. In particular, the control circuit 36 can more appropriately limit the supply power when using count map information corresponding to different battery temperatures and/or different remaining capacities.

(fourth embodiment)

< 4-1. different points from the first embodiment >

Since the basic configuration of the fourth embodiment is the same as that of the first embodiment, the description of the common configuration is omitted, and the description of the different points is mainly given. Note that the same reference numerals as those in the first embodiment denote the same structures, and the above description is referred to.

In the first embodiment described above, the battery control circuit 65 calculates the protection count value, and transmits the calculated protection count value and the count threshold value to the control circuit 36 of the work machine 1 as battery information. In contrast, in the fourth embodiment, the protection count value and the count map are transmitted from the battery control circuit 65 to the control circuit 36. Further, the control circuit 36 receives the protection count value from the battery control circuit 36, and calculates the protection count value by itself in a cycle shorter than the cycle of receiving the protection count value.

Specifically, the fourth embodiment differs from the first embodiment with respect to the battery communication processing in S100 of the battery state processing shown in fig. 4. In the fourth embodiment, the control circuit 36 executes the processing shown in the flowchart of fig. 21 in the battery communication processing in S100. Further, between the processes of S400 and S410 of the motor driving process shown in fig. 6, the guard count process shown in fig. 22 is executed. Further, in the current upper limit value setting process in S410 of the motor driving process shown in fig. 6, the process shown in the flowchart of fig. 24 or fig. 25 is executed.

< 4-2. processing in working machine >

< 4-2-1. Battery communication processing >

Next, details of the battery communication process executed by the control circuit 36 in S100 will be described with reference to the flowchart of fig. 21.

In S105, the control circuit 36 determines whether the initial communication has been completed. If it is determined in S105 that the initial communication is not completed, the process proceeds to S115, and if it is determined that the initial communication is completed, the process proceeds to S125.

In S115, the control circuit 36 executes initial communication processing. Specifically, the control circuit 36 receives the count map, the addition threshold, the subtraction threshold, the protection threshold, the count threshold, and a later-described time threshold from the battery control circuit 65. Fig. 26 shows an example of the count map. The count map may also be a count map corresponding to the battery temperature and/or the remaining capacity. On the other hand, in S125, the protection count value calculated by the battery control circuit 65 is received.

Further, the control circuit 36 may receive a count map or the like from the battery control circuit 65 in addition to the initial communication when the work machine 1 is connected to the battery pack 22. For example, control circuit 36 may receive the count map or the like from battery control circuit 65 when work implement 1 is restarted by re-supplying electric power after electric power supply from battery pack 22 is stopped and work implement 1 is stopped.

< 4-2-2. protection count processing >

Next, details of the protection count process executed by the control circuit 36 between the processes of S400 and S410 will be described with reference to the flowchart of fig. 22.

First, in S205, a guard count value calculation process is performed to calculate a guard count value. The details of the process of calculating the guard count value will be described later.

Next, in S215, the control circuit 36 determines whether or not the guard count value at the current time is acquired through communication with the battery pack 22. The guard count value at the current time is, for example, a guard count value between the current guard count processing cycle and a time traced back for a predetermined period from the current guard count processing cycle. Alternatively, the current guard count value is the guard count value between the last guard count processing cycle and the current guard count processing cycle. Since the cycle of the battery communication process is longer than the cycle of the protection count process, the protection count value may be acquired from the battery pack 22 or may not be acquired between the cycles of the protection count process.

If it is determined in S215 that the guard count value has been acquired, the process proceeds to S225, and if it is determined that the guard count value has not been acquired, the process is terminated.

In S225, the control circuit 36 updates the battery protection count value possessed by the control circuit 36 to the protection count value acquired from the battery pack 22, and ends the present process. That is, when the protection count value at the present time is acquired from the battery pack 22, the control circuit 36 preferentially uses the protection count value acquired from the battery pack 22 over the protection count value calculated by the control circuit 36. When the protection count value at the current time is not acquired from the battery pack 22, the control circuit 36 uses the protection count value calculated by the control circuit 36.

< 4-2-2. calculation of guard count value >

Next, details of the guard count value calculation process executed by the control circuit 36 in S205 will be described with reference to the flowchart of fig. 23.

First, in S305 to S345, the same processing as in S800 to S840 shown in fig. 15 is executed. That is, in S325 and S345, the guard count value is updated to a value obtained by adding an addition value to the guard count value or a value obtained by subtracting a subtraction value from the guard count value.

At this time, the protection count value before updating is a value calculated in the previous protection count processing calculation processing cycle or a protection count value updated to the acquisition value from the battery pack 22 in S225. Therefore, the control circuit 36 executes the battery communication process to acquire the protection count value from the battery control circuit 65. Further, the control circuit 36 adds an addition value or a subtraction value to the protection count value acquired from the battery control circuit 65 by the latest communication between the cycles of the battery communication processing, and calculates the protection count value at the current time.

< 4-2-3. Current Upper Limit value setting Process

Next, details of the current upper limit value setting process executed by the control circuit 36 in S410 will be described with reference to the flowchart of fig. 24.

In S405, the control circuit 36 executes time prediction processing until the battery pack 22 becomes an overload stop. When the protection count value reaches the protection threshold value, the battery pack 22 outputs a discharge prohibition signal due to overload, and enters a discharge stop state. The control circuit 36 uses the received count map to predict the time until the protection count value reaches the protection threshold.

In S415, the control circuit 36 determines whether or not the time until the stop predicted in S405 is less than a time threshold. In S415, if it is determined that the time to stop is equal to or longer than the time threshold, the process proceeds to S425, and if it is determined that the time to stop is shorter than the time threshold, the process proceeds to S435. That is, the control circuit 36 proceeds to the process of S435 when a sign indicating that the battery pack 22 is performing the protection operation is detected based on the comparison between the time until the stop and the time threshold, and proceeds to the process of S425 when the sign is not detected.

In S425, the control circuit 36 sets a normal current value to the current upper limit value. The current value is usually a current value equal to or larger than the addition threshold. That is, the normal current value is a value that increases the guard count value.

On the other hand, in S435, the control circuit 36 sets a limit current value to the current upper limit value. The limit current value may be a current value smaller than the addition threshold value. That is, the limit current value may be a value that keeps the guard count value at a constant value or less.

Alternatively, as shown in fig. 27, the current limit value may be a value set according to the guard count value. For example, as shown in fig. 26, when the guard count value is 60% of the guard threshold value, the current limit value is set to 70A so as to limit the addition value to 2 or less. Further, when the guard count value increases to a value of 80% of the guard threshold value, the current limit value is set to 60A so as to limit the addition value to 1 or less. Further, when the guard count value rises to a value of 90% of the guard threshold value, the current limit value is set to 50A so as to limit the addition value to 0 or less. That is, instead of limiting the discharge current suddenly to a value at which the addition value becomes 0 or less, the discharge current may be limited so that the increase of the guard count value becomes slow, and the discharge current may be limited to a value at which the guard count value does not increase immediately before the guard count value reaches the guard threshold value. In this way, the user can continue to use the work machine without reducing the output of the work machine as much as possible, as compared with the case where the discharge current is suddenly limited to a value at which the addition value becomes 0 or less.

< 4-2-3. Another example of the Current Upper Limit value setting processing

Next, details of another example of the current upper limit value setting process executed by the control circuit 36 in S410 will be described with reference to the flowchart of fig. 25.

In S505, S515, and S545, the same processing as in S405 to S435 is executed.

Further, in S515, if it is determined that the time until the stop is equal to or longer than the time threshold, the process proceeds to S525. In S525, the control circuit 36 determines whether the guard count value is larger than the count threshold value. When it is determined in S525 that the guard count value is larger than the count threshold value, the process proceeds to S545, and a limit current value is set for the current upper limit value.

On the other hand, when it is determined in S525 that the guard count value is equal to or less than the count threshold, the process proceeds to S535, and a normal current value is set for the current upper limit value. That is, in another example of the current upper limit value setting process, a sign of the battery pack 22 performing the protection operation is detected based on a comparison between the time until the stop and the time threshold and a comparison between the protection count value and the count threshold.

Fig. 28 is a diagram showing an outline of a data flow between battery pack 22 and work implement 1 when the main process according to the present embodiment is executed. In the initial communication, the count map, the addition threshold, the subtraction threshold, the protection threshold, and the time threshold are transmitted from battery pack 22 to work implement 1. Further, the battery pack 22 calculates a guard count value, and transmits the calculated guard count value to the work machine 1 at a predetermined cycle.

In work machine 1, the protection count value at the present time is calculated from the received protection count value, the count map, and the discharge current value. Further, in work machine 1, the discharge current is limited using the calculated guard count value at the present time and the time threshold value. Alternatively, work implement 1 limits the discharge current using the calculated protection count value at the present time, the time threshold value, and the count value calculated from the received protection threshold value.

< 4-3. Effect >

According to the fourth embodiment described above, the effects (1) to (8) of the first embodiment are exhibited, and the following effects (11) to (12) are exhibited.

(11) When the protection count value at the present time is acquired from the battery pack 22, the control circuit 36 preferentially uses the protection count value acquired from the battery pack 22 over the protection count value calculated by the control circuit 36. Therefore, the control circuit 36 uses the same value as the value used by the battery pack 22 to perform the protection operation as much as possible, and therefore can detect the indication that the battery pack 22 performs the protection operation with high accuracy.

(12) The guard count value is calculated by the control circuit 36 by adding or subtracting an addition value or a subtraction value to the guard count value acquired from the battery pack 22 in the past. Therefore, the control circuit 36 uses the value for the battery pack to perform the protection operation as much as possible, and therefore can detect the sign of the battery pack 22 performing the protection operation with high accuracy.

(fifth embodiment)

< 5-1. different from the first embodiment

Since the basic configuration of the fifth embodiment is the same as that of the first embodiment, the description of the common configuration is omitted, and the description of the different points is mainly given. Note that the same reference numerals as those in the first embodiment denote the same structures, and the above description is referred to.

In the first embodiment described above, when the control circuit 36 detects a sign of the protective operation performed by the battery pack 22, the control circuit suppresses the discharge current and suppresses the progress of the overload state of the battery pack 22. In contrast, the fifth embodiment is different from the first embodiment in that the control circuit 36 temporarily stops the motor 50 and prompts recovery of the battery pack 22 when a sign of the protective operation performed by the battery pack 22 is detected. In the fifth embodiment, the control circuit 36 executes the overload stop processing shown in the flowchart of fig. 29, instead of the current upper limit value setting processing in S410.

As shown in the count maps of fig. 19 and 26, when the motor 50 is stopped and the discharge current becomes 0A, the subtraction value is subtracted from the guard count value, and the guard count value is decreased. By restarting the motor 50 after the guard count value has decreased to the predetermined value, the stop time of the working machine 1 is suppressed to a relatively short time as compared with the case where the battery pack 22 performs the guard operation. When the battery pack 22 performs the protection operation and outputs the discharge prohibition signal, the stop period of the motor 50 is, for example, 3 to 5 minutes. In contrast, when the work machine 1 stops the motor 50 before the battery pack 22 performs the protection operation, the stop period of the motor 50 is, for example, 20 to 30 seconds.

< 5-2. overload stop processing >

Next, details of the overload stop process executed by the control circuit 36 in place of the current upper limit value setting process in S410 will be described with reference to a flowchart shown in fig. 29.

First, in S605, the control circuit 36 determines whether or not the stop flag is cleared. When the stop flag is set, the control circuit 36 detects an abnormality in the processing of S50. As a result, the supply of electric power from the battery 60 to the motor 50 is stopped, and the motor 50 is stopped.

If it is determined in S605 that the stop flag is cleared, the process proceeds to S615. In S615, the control circuit 36 determines whether the guard count value is larger than the set stop threshold value. If it is determined in S615 that the guard count value is greater than the stop threshold, the process proceeds to S625, and if it is determined that the guard count value is equal to or less than the stop threshold, the process proceeds to S645.

In S625, the control circuit 36 sets the stop flag. Next, in S635, the control circuit 36 sets a second count value for the stop threshold value, and ends the present process. The second count value is a value smaller than a protection threshold value at which the battery pack 22 performs a protection action. In the present embodiment, the second count value corresponds to an example of the second stop threshold value.

On the other hand, in S645, the control circuit 36 determines whether the guard count value is smaller than the third count value. The third count value is a value smaller than the second count value. If it is determined in S645 that the guard count value is smaller than the third count value, the process proceeds to S655, and if it is determined that the guard count value is equal to or larger than the third count value, the process is terminated.

In S655, the control circuit 36 sets a first count value for the stop threshold value, and ends the present process. The first count value is a value smaller than the second count value and larger than the third count value. In the present embodiment, the first count value corresponds to an example of the first stop threshold value.

When it is determined in S605 that the stop flag is set, the process proceeds to S665. In S665, the control circuit 36 determines whether the guard count value is smaller than the first count value. In S665, if it is determined that the guard count value is smaller than the first count value, the process proceeds to S675, and if it is determined that the guard count value is equal to or larger than the first count value, the process is terminated. In S675, the control circuit 36 clears the stop flag, and ends the present process.

< 5-3. action of work machine

Next, the operation of work machine 1 when control circuit 36 executes the overload stop process will be described with reference to the timing chart of fig. 30. In the timing chart of the guard count value shown in fig. 30, the hatched portion indicates the stop period of the motor 50. The dot-hatching in the hatching indicates a period in which the motor 50 can be restarted by pulling the trigger 11, and the hatching in the diagonal lines indicates a period in which the restart of the motor 50 is prohibited regardless of the presence or absence of the operation of the trigger 11.

At time t10, trigger 11 is pulled to turn on trigger switch 12, and a discharge current equal to or greater than the addition threshold flows, and the guard count value starts to increase. At this time, the stop threshold value is set to the first count value.

At time t11, when the guard count value exceeds the stop threshold value (equal to the first count value), a second count value is set for the stop threshold value. Further, the motor 50 is temporarily stopped, and a period during which the motor 50 can be restarted is entered. Since the motor 50 is stopped and the discharge current does not flow, the guard count value starts to decrease.

Further, when the trigger 11 is released and the trigger switch 12 is temporarily turned off at time t12, and the trigger 11 is pulled and the trigger switch 12 is turned on at time t13, the motor 50 is restarted and a discharge current flows.

Further, at time t14, when the guard count value exceeds the stop threshold value (i.e., the second count value), the motor 50 is stopped, and a period during which the motor 50 cannot be restarted is entered. The load on the motor 50 increases from time t13 to time t14, and the discharge current value increases, as compared with the period from time t10 to time t 11. Therefore, the rate of increase in the guard count value becomes greater during the period from time t13 to time t14 than during the period from time t10 to time t 11.

At time t14, when the motor 50 stops, the guard count value starts to decrease. At time t15, the trigger 11 is released to turn off the trigger switch 12, and at time t16, the trigger 11 is pulled to turn on the trigger switch 12. However, since the motor 50 cannot be restarted, the motor 50 is maintained in a stopped state and the discharge current does not flow. At time t11, when the use of work implement 1 is continued by temporarily stopping motor 50, the user can recognize that the period during which restart of motor 50 is impossible has come.

At time t17, trigger 11 is released to open trigger switch 12. At time t18, the guard count value becomes equal to or less than the first count value, and the period during which the motor 50 cannot be restarted shifts to a period during which the restart is possible.

Further, at time t19, when the trigger 11 is pulled and the trigger switch 12 is turned on, the motor 50 is restarted and a discharge current flows. At time t20, when the guard count value exceeds the stop threshold value again (i.e., the second count value), the motor 50 is stopped, and a period during which the motor 50 cannot be restarted is entered.

In the period from time t19 to time t20, the load on the motor 50 is reduced and the discharge current value is reduced, as compared with the period from time t13 to time t 14. Therefore, the rate of increase in the guard count value is smaller during the period from time t19 to time t20 than during the period from time t13 to time t 14.

At time t20, when the motor 50 stops, the guard count value starts to decrease. At time t21, trigger 11 is released to open trigger switch 12. At time t22, the guard count value becomes equal to or less than the first count value, and the period during which the motor 50 cannot be restarted shifts to a period during which the restart is possible. However, since the trigger 11 is not pulled, the motor 50 is not restarted and the guard count continues to decrease.

Further, at time t23, if the guard count value is smaller than the third count value, the first count value is set to the stop threshold value. At time t24, when the trigger 11 is pulled and the trigger switch 12 is turned on, the motor 50 is restarted and the discharge current starts to flow. In addition, the guard count value starts to increase. At time t25, when the guard count value exceeds the stop threshold value (equal to the first count value), the motor 50 is stopped, and a period during which the motor 50 can be restarted is entered. In the present embodiment, since the discharge current is not limited, the discharge current varies in accordance with the load variation of the motor 50 over the entire period.

< 5-4. Effect >

According to the fifth embodiment described above, the following effects (13) to (15) are exhibited.

(13) The control circuit 36 stops the motor 50 before the protection operation by the battery pack 22 is executed. This enables the battery pack 22 to be recovered in a relatively shorter time than when the battery pack 22 performs a protection operation. Further, the user can continue to use the work machine 1 through a relatively short stop period of the work machine 1. Further, the user can continue to use the work machine 1 without limiting the output of the battery pack 22.

(14) If the guard count value exceeds a stop threshold value smaller than the guard threshold value, the motor 50 is stopped. Thereby, the guard count value is decreased. As a result, the battery pack 22 can be recovered through a relatively short stop period of the motor 50. Further, the motor 50 can continue to receive power supply from the battery pack 22 after a relatively short stop period.

(15) When the guard count value exceeds the stop threshold value set with the first count value, the motor 50 is stopped, and when the trigger 11 is operated after the motor 50 is stopped, the motor 50 is restarted. Further, when the guard count value exceeds the stop threshold value set with the second count value, the motor 50 is stopped, and the restart of the motor 50 is prohibited until the guard count value becomes lower than the first count value. Thus, when the motor 50 is temporarily stopped, the user can continue to use the work machine 1 by operating the trigger 11, and can recognize that the period in which the work machine 1 cannot be used has come by continuing to use the work machine.

(other embodiments)

While the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the embodiments described above, and can be implemented in various modifications.

(a) In each of the above embodiments, the battery pack 22 operates the protection function when the protection count value exceeds the protection threshold value, but the present disclosure is not limited thereto. The battery pack 22 may operate the protection function when the remaining capacity of the battery 60 is lower than the first capacity threshold. That is, when the battery pack 22 is in the overdischarge state, the protection function may be activated to prohibit the discharge.

Further, the control circuit 36 may set a limit current value to the current upper limit value when the remaining capacity acquired from the battery pack 22 is lower than the second capacity threshold value. Alternatively, the control circuit 36 may set the limit duty to the duty upper limit value when the acquired remaining capacity is lower than the second capacity threshold. The second capacity threshold is a value greater than the first capacity threshold. In this case, the control circuit 36 detects a sign of the protection function operation when the remaining capacity is lower than the second capacity threshold.

(b) In addition, the battery pack 22 may operate the protection function when the battery temperature exceeds the first temperature threshold. That is, when the battery pack 22 is in a high-temperature state, the protection function may be activated to prohibit discharge.

The control circuit 36 may set a limit current value to the current upper limit value when the battery temperature acquired from the battery pack 22 exceeds the second temperature threshold value. Alternatively, the control circuit 36 may set the limit duty to the duty upper limit value when the acquired battery temperature exceeds the second temperature threshold. The second temperature threshold is a value smaller than the first temperature threshold. In this case, the control circuit 36 detects a sign of the protective function operation when the battery temperature exceeds the second temperature threshold.

(c) In the first embodiment, the normal current value is set to the current upper limit value when the guard count value is equal to or less than the count threshold value, but the current upper limit value may not be set when the guard count value is equal to or less than the count threshold value. In this case, the control circuit 36 may calculate the duty ratio so as to satisfy the condition (2) in the processing of S420.

(d) In the first embodiment, the current upper limit value is set to any one of two-stage values, but may be set to any one of three or more-stage values. For example, a first count threshold and a second count threshold smaller than the first count threshold are set as thresholds smaller than the guard threshold. Further, when the guard count value is smaller than the second count threshold value, the control circuit 36 sets the normal current value to the current upper limit value. The control circuit 36 sets a first limit current value to the current upper limit value when the guard count value is equal to or greater than the first count threshold value, and sets a second limit current value to the current upper limit value when the guard count value is smaller than the first count threshold value and equal to or greater than the second count threshold value. The first current limit value and the second current limit value are both values smaller than the addition threshold value, and the first current limit value is a value smaller than the second current limit value. Similarly, in the second embodiment, the duty upper limit value may be set to any one of three or more stages.

(e) The first embodiment may be combined with the second embodiment. Specifically, in the first embodiment, the control circuit 36 of the work machine 1 may calculate the protection count value instead of receiving the protection count value from the battery control circuit 65 as in the second embodiment. In this case, the battery control circuit 65 may not calculate the guard count value.

In the second embodiment, the battery control circuit 65 may calculate the protection count value as in the first embodiment. In this case, instead of calculating the protection count value, the control circuit 36 of the work machine 1 may receive the protection count value, the addition threshold value, and the subtraction threshold value from the battery control circuit 65.

(f) In the third embodiment, in the process of S505, the control circuit 36 sets the count threshold value based on the magnitude of the discharge current and the count map information, but may set the limit current value based on the magnitude of the discharge current and the count map information. For example, the control circuit 36 may set the limiting current value to a relatively small value when the rate of increase of the guard count value estimated from the count map information is relatively large, and set the limiting current value to a relatively large value when the rate of increase of the guard count value is relatively small.

(g) In each of the above embodiments, the number of communication lines constituting each of second connection line 49 and second battery connection line 69 is not limited to one, and may be two. When the second connection line 49 and the second battery connection line 69 include two communication lines, one communication line is a dedicated transmission line for transmitting data from the control circuit 36 to the battery control circuit 65, and the other communication line is a dedicated transmission line for transmitting data from the battery control circuit 65 to the control circuit 36. When the second connection line 49 and the second battery connection line 69 include two communication lines, the serial terminal 44 and the battery serial terminal 64 each include two terminals for serial communication. Further, the two communication lines are connected to terminals for serial communication, respectively. In this way, when the second connection line 49 and the second battery connection line 69 include two communication lines, the communication speed between the control circuit 36 and the battery control circuit 65 can be increased as compared with the case where only one communication line is included. Even in this case, the supply of electric power from the battery pack 22 to the motor 50 can be appropriately limited.

(h) The present disclosure is not limited to application to a mower, and may be applied to various working machines configured to drive a working tool with a rotational force, such as an electric power tool, for example, a power saw, a hedge trimmer, a hair clipper, and an impact driver.

(i) The control Circuit 36 and the battery control Circuit 65 may be provided with a combination of individual electronic components instead of or in addition to the microcomputer, may be provided with an Application Specific Integrated Circuit (ASIC), may be provided with an Application Specific Standard Product (ASSP), may be provided with a Programmable logic device such as a Field Programmable Gate Array (FPGA), or may be provided with a combination of these components.

(j) The plurality of components may realize a plurality of functions of one component in the above embodiments, or a plurality of components may realize one function of one component. Further, a plurality of functions provided by a plurality of components may be realized by one component, or one function realized by a plurality of components may be realized by one component. In addition, a part of the structure of the above embodiment may be omitted. At least a part of the structure of the above embodiment may be added to or replaced with the structure of the other above embodiment.

(k) The present disclosure can be achieved by various modes such as a system including the electric working machine and the battery pack as components, a motor driving method, and the like, in addition to the electric working machine described above.