阅读说明：本技术 一种新能源汽车均衡控制方法 (New energy automobile balance control method ) 是由 王凯 沈春华 于 2021-07-05 设计创作，主要内容包括：本发明公开了一种新能源汽车均衡控制方法,包括以下步骤:1)根据车辆用车习惯,分析得到车辆经常不使用的时间段,判断电池是否需要均衡；2)记录均衡电池串数和均衡时间,判断车辆满足的条件,并在车辆上电后将均衡信息上传至仪表端；3)车辆根据满足的不使用时间的条件进行均衡,均衡完成后BMS清除存储的均衡信息,本发明通过BMS记录的充放电时间,分析用车习惯,选择适当的方法进行均衡,将需要均衡的目标电池电压降至和平均电池电压接近的程度,使得电池的一致性得到改善,从而延长电池的使用寿命,用户可以获取到电芯的数据,对电池一致性有更深刻的认知；人工均衡可以控制均衡的时间,操作简单,用户体验更好。(The invention discloses a balance control method for a new energy automobile, which comprises the following steps of 1) analyzing a time period when a vehicle is frequently not used according to vehicle using habits, and judging whether a battery needs to be balanced or not; 2) recording the number of the equalizing batteries and the equalizing time, judging the conditions met by the vehicle, and uploading the equalizing information to an instrument end after the vehicle is powered on; 3) the vehicle is balanced according to the condition of the satisfied non-use time, and the BMS clears the stored balance information after the balance is completed; the manual balancing can control the balancing time, the operation is simple, and the user experience is better.)

1. The new energy automobile balance control method is characterized by comprising the following steps:

1) analyzing to obtain a time period when the vehicle is frequently not used according to the vehicle using habit of the vehicle, and judging whether the battery needs to be balanced or not;

2) recording the number of the equalizing batteries and the equalizing time, judging three conditions met by the vehicle, and uploading equalizing information to an instrument end after the vehicle is powered on;

3) and balancing the vehicle according to the satisfied condition of the unused time, and clearing the stored balance information by the BMS after the balance is completed.

2. The balance control method for the new energy automobile according to claim 1, wherein in the step 2), a first condition is that when the vehicle has a current charge which continuously exceeds a fixed time value for no less than one time in a period, the vehicle is judged to use a first balance method, a second condition is that when the vehicle has a current charge which continuously exceeds the fixed time value for no less than one time in the period, the vehicle is judged to use a second balance method, and a third condition is that the vehicle is judged to use a third balance method on the premise that the second condition is not met.

3. The balance control method for the new energy automobile as claimed in claim 2, wherein the meeting of the condition is to perform the balance during the slow charging of the vehicle, and when the difference between the target battery voltage and the lowest battery voltage reaches a predetermined value, the balance switch of the target battery is turned on, and the battery is passively discharged through a balance circuit on the BMS until the difference between the target battery voltage and the lowest battery voltage reaches the predetermined value.

4. The new energy automobile balance control method according to claim 2, characterized in that off-line balance is adopted when the second condition is met, the BMS sets the RTC to wake up after a fixed time value before sleeping, Memory data is read, the BMS sets the balance time of the target battery corresponding to the battery sampling chip, and the battery sampling chip turns off a balance switch of the target battery after the balance time of the target battery is reached.

5. The balance control method of the new energy automobile according to claim 2, characterized in that the balance is performed in the discharging process of the automobile when the condition III is met, and the balance switch of the target battery is turned off after the balance time is reached, so that the balance is finished.

6. The balance control method for the new energy automobile according to claim 4, wherein the BMS sets the maximum balance time again and checks the battery state after awakening through the RTC.

7. The balance control method for the new energy automobile according to claim 1, wherein in the 1), before the BMS sleeps in the time period, the RTC is set to wake up after a fixed time value, after waking up, the BMS records a target battery string number exceeding the average battery voltage by 100mV, inquires a battery capacity value corresponding to the target battery voltage and the average battery voltage, and calculates the balance current and the balance time.

8. The balance control method for the new energy automobile as claimed in claim 7, wherein in 1), when the balance time is less than or equal to 1h, no information is stored, and only when the balance time is greater than 1h, the corresponding target battery string number and the balance time thereof are stored in the Memory, and then the BMS goes to sleep.

9. The balance control method for the new energy automobile according to claim 1, wherein in 2), after the BMS powers on the automobile, the BMS sends data stored in the Memory last time to the instrument end through the CAN network, and balance setting is performed through balance options of an instrument interface.

10. The balance control method of the new energy automobile according to claim 9, characterized in that a balance start option on a main interface is used, meanwhile, a meter sends a balance command to the BMS through a CAN network, and then the BMS sets the time for balancing the target battery through a battery sampling chip and starts the balance.

Technical Field

The invention relates to the technical field of new energy automobile battery management, in particular to a new energy automobile balance control method.

Background

At present, most of existing new energy automobiles are driven by batteries serving as power sources, so that the monitoring of the states of the batteries is indispensable, and in consideration of safety and service life, the consistency of the batteries in the use process is very important, so that the consistency of the batteries in long-term operation is kept, and the batteries need to be subjected to equalization treatment by a BMS. The equalization is divided into active equalization and passive equalization; due to the restriction of cost, most of the existing equalization strategies adopt passive equalization; in a common equalizing strategy in the market, in a charging stage, after a highest single battery reaches a predetermined value (for example, a voltage of a lithium iron phosphate single battery reaches 3.55V), when a voltage difference between the single battery and a lowest battery reaches the predetermined value (for example, a voltage difference between the lithium iron phosphate single battery and the lowest battery reaches 300 mV), an equalizing switch of the single battery is turned on, and passive discharge is performed through an equalizing circuit on the BMS until the voltage difference between the single battery and the lowest battery reaches the predetermined value (for example, the voltage difference between the lithium iron phosphate single battery and the lowest battery reaches 100 mV) or the charging is finished, and the equalizing switch is turned off; although the cell can be balanced by the balancing strategy, the balancing time is short and the actual effect is not great due to more balancing starting conditions; in order to solve the problems, a new balance control strategy is provided, the strategy not only carries out balance under the condition of not influencing personal use, but also can improve the balance effect by increasing the balance time; meanwhile, the strategy can manually start the balancing function, freely control the balancing time, facilitate the operation and better balance the battery cell, thereby improving the consistency of the battery; thereby prolonging the service life of the battery and increasing the endurance of the vehicle; the user can also acquire the performance of the vehicle battery through the equalization information.

Disclosure of Invention

In order to solve the problems, the invention discloses a new energy automobile balance control method, which comprises the following steps:

1) analyzing to obtain a time period when the vehicle is frequently not used according to the vehicle using habit of the vehicle, and judging whether the battery needs to be balanced or not;

2) recording the number of the equalizing batteries and the equalizing time, judging three conditions met by the vehicle, and uploading equalizing information to an instrument end after the vehicle is powered on;

3) and balancing the vehicle according to the satisfied condition of the unused time, and clearing the stored balance information by the BMS after the balance is completed.

As an improvement of the present invention, in the step 2), the first condition (i) is to determine that the vehicle uses the first equalizing method when the vehicle has a current charge continuously exceeding a fixed time value for at least one time in a cycle, the second condition (i) is to determine that the vehicle uses the second equalizing method when the vehicle has a current charge continuously exceeding the fixed time value for at least one time in the cycle and does not satisfy the first condition, and the third condition (i) is to determine that the vehicle uses the third equalizing method when the second condition is not satisfied.

As an improvement of the present invention, the equalization is performed during the slow charging process of the vehicle when the condition is satisfied, after the highest single battery reaches the predetermined value, when the difference between the target battery voltage and the lowest battery voltage reaches the predetermined value, the equalization switch of the target battery is turned on, the passive discharge is performed by the equalization circuit on the BMS until the difference between the target battery voltage and the lowest battery voltage reaches the predetermined value or the charging is finished, the equalization switch is turned off, and the equalization is finished.

As an improvement of the invention, off-line equalization is adopted when the condition II is met, and the time period of the vehicle which is not frequently used is obtained by analysis according to the use habit of the vehicle, and equalization is carried out at the time; when the BMS is in the time period and before the BMS sleeps, the RTC is set to wake up after a fixed time value, Memory (Memory) data is read, the BMS sets the balance time of a battery sampling Chip (CMU) corresponding to a target battery, the battery sampling chip disconnects a balance switch of the target battery after the balance time of the target battery is reached, then the BMS sets the maximum balance time again and then wakes up through the RTC (real-time clock), and the BMS goes to sleep; the battery state is checked after the BMS wakes up again, the BMS directly enters the dormancy after detecting that no monomer needing to be balanced exists, if the monomer needing to be balanced still exists, the BMS sets the target battery needing to be balanced again and then enters the dormancy again after setting the RTC wake-up time until the BMS detects that no monomer battery needing to be balanced or the vehicle starts, the balancing switch is switched off, and the balancing is finished.

As an improvement of the invention, the balancing is carried out in the vehicle discharging process when the condition III is met, the balancing switch of the target battery is turned on in the vehicle discharging process, and the balancing switch of the target battery is turned off after the balancing time is reached, so that the balancing is finished.

As an improvement of the present invention, in 1), when in the time period, before the BMS sleeps, the BMS sets the RTC to wake up after a fixed time value, and after waking up, the BMS records a target battery string number exceeding the average battery voltage by 100mV, queries a battery capacity value corresponding to the target battery voltage and the average battery voltage by referring to an OCV table (open circuit voltage table), and takes an absolute value of a difference between the target battery voltage and the average battery voltage, calculates an equalization current by using an equalization resistance, and calculates a required equalization time by (capacity difference)/(equalization current).

As an improvement of the present invention, in 1), when the equalization time is less than or equal to 1h, no information is stored, and only when the equalization time is greater than 1h, the corresponding target battery string number and the equalization time thereof are stored in the Memory, and then the BMS goes to sleep, and after each judgment is finished, the latest data will cover the original data and will not occupy too much storage space.

As an improvement of the invention, in 2), after the vehicle is powered on, the BMS sends the data stored in the Memory last time to the meter end through the CAN network, and performs balance setting through balance options of the meter interface.

As an improvement of the invention, a balance option is added on a main interface of the instrument, and a lower menu of the balance option is divided into balance starting and detailed information; after the balancing is selected to be started, one-key balancing is carried out, the instrument interface prompts the time of the vehicle needing balancing, meanwhile, the instrument sends a balancing instruction to the BMS through the CAN network, the BMS sets the balancing time of the target battery through the CMU, the balancing is started, the instrument end displays the completion of operation, the vehicle CAN be powered off manually, the balancing process is completed through the CMU, and the balancing process CAN be stopped through the starting of the vehicle at any time; selecting detailed information and then displaying the average battery voltage, the target battery string number, the target battery voltage and the target battery equalization time; and after the balance is finished, the BMS clears the stored balance information.

The invention has the beneficial effects that: when the BMS detects that the battery needs to be balanced, the BMS analyzes the vehicle using habit through the charging and discharging time recorded by the BMS, selects a proper method for balancing, and reduces the target battery voltage needing to be balanced to a degree close to the average battery voltage, so that the consistency of the battery is improved, the service life of the battery is prolonged, and the endurance of the vehicle is increased; meanwhile, through the balance function of the instrument, a user can acquire the data of the battery core, and the battery consistency is deeply known; meanwhile, the manual equalization can control the equalization time, the operation is simple, and the user experience is better.

Drawings

Fig. 1 is a flowchart of the equalization control method according to the present invention.

Detailed Description

The present invention will be further illustrated with reference to the accompanying fig. 1 and the following detailed description, which is to be understood as merely illustrative and not restrictive in scope.

Example (b): as shown in fig. 1, a new energy automobile balance control method analyzes a time period of vehicle nonuse according to data in the past 30 days, wherein the time period is between 2h and 8 h; during this time period, before the vehicle is powered off, the BMS sets a wake-up time; after the awakening time is reached, the BMS acquires a target battery needing to be balanced and the balancing time of the target battery; after the vehicle is started next time, the BMS sends the recorded data to an instrument end through a CAN network, and the instrument stores the data for user operation; the BMS analyzes the use habits of the vehicles and selects a corresponding balancing method for balancing; after the balance is finished, the BMS clears the stored balance information; the above steps are performed in a cyclic operation, and the method specifically comprises the following steps:

1) analyzing to obtain a time period when the vehicle is frequently not used according to the vehicle using habit of the vehicle, and judging whether the battery needs to be balanced or not;

2) recording the number of the equalizing batteries and the equalizing time, judging three conditions met by the vehicle, and uploading equalizing information to an instrument end after the vehicle is powered on;

3) and balancing the vehicle according to the satisfied condition of the unused time, and clearing the stored balance information by the BMS after the balance is completed.

Further, in the 2), the condition one is: when the vehicle is in 24h period, and the low-current charging with the duration exceeding 8h exists for 2 times in every 30 periods, the vehicle is considered to be capable of using the first equalization method, the second equalization method is considered to be not satisfied, when the vehicle is in 24h period, and the vehicle is not in use for 2 times in every 30 periods, the vehicle is considered to be capable of using the second equalization method, and the third equalization method is judged to be used on the premise that the second equalization method is not satisfied.

Further, an equalization method is adopted when the condition one is met: and carrying out equalization in the vehicle slow charging process. After the highest single battery reaches a preset value (for example, the voltage of a lithium iron phosphate single battery reaches 3.55V), when the difference value between the target battery voltage and the lowest battery voltage reaches the preset value (for example, the voltage difference value of lithium iron phosphate reaches 150 mV), an equalizing switch of the target battery is turned on, and passive discharge is carried out through an equalizing circuit on the BMS until the difference value between the target battery voltage and the lowest battery voltage reaches the preset value (for example, the voltage difference value of lithium iron phosphate reaches 50 mV), or the charging is finished, the equalizing switch is turned off, and the equalization is finished.

Further, an equalization method II is adopted when the condition II is met: and (5) off-line equalization. According to the using habit of the vehicle, analyzing to obtain the time period of the vehicle which is not used frequently, and balancing at the time; when the BMS is in the time period, before the BMS sleeps, the RTC is set to wake up after 0.5h, Memory data is read, the BMS sets the balance time of a battery sampling Chip (CMU) corresponding to the target battery, the battery sampling chip switches off a balance switch of the target battery after the balance time of the target battery is reached, and then the BMS wakes up through the RTC after the BMS sets the maximum balance time again, and enters the sleep; the battery state is checked after the BMS wakes up again, the BMS directly enters the dormancy after detecting that no monomer needing to be balanced exists, if the monomer needing to be balanced still exists, the BMS sets the target battery needing to be balanced again and then enters the dormancy again after setting the RTC wake-up time until the BMS detects that no monomer battery needing to be balanced or the vehicle starts, the balancing switch is switched off, and the balancing is finished.

Further, an equalization method is adopted when the condition three is met: equalization is performed during vehicle discharge. And in the discharging process of the vehicle, starting the balance switch of the target battery, disconnecting the balance switch of the target battery after the balance time is reached, and finishing the balance.

Further, in the step 1), according to the using habit of the vehicle, analyzing to obtain a time period that the vehicle is frequently not used, wherein the time period exceeds 2h and does not exceed 8h, when the time period is within the time period, the BMS sets the RTC to wake up after 2h before sleeping, and after waking up, the BMS records the number of target battery strings exceeding the average battery voltage by 100mV, and queries the battery capacity value corresponding to the target battery voltage and the average battery voltage by comparing the OCV table (open-circuit voltmeter), and takes the absolute value of the difference between the two, calculates the equalizing current by the equalizing resistance, and calculates the required equalizing time by (capacity difference)/(equalizing current).

Further, in the step 1), when the equalization time is less than or equal to 1h, no information is stored, only when the equalization time is greater than 1h, the corresponding target battery string number and the equalization time thereof are stored in the Memory, and then the BMS goes to sleep, and after each judgment is finished, the latest data covers the original data and does not occupy too much storage space.

Further, in 2), after the vehicle is powered on, the BMS sends the data stored in the Memory last time to the meter end through the CAN network, and performs balance setting through a balance option of the meter interface.

Further, balance options are added on a main interface of the instrument, and a lower menu of the balance options is divided into balance starting and detailed information; after the balancing is selected to be started, one-key balancing is carried out, the instrument interface prompts the time of the vehicle needing balancing, meanwhile, the instrument sends a balancing instruction to the BMS through the CAN network, the BMS sets the balancing time of the target battery through the CMU, the balancing is started, the instrument end displays the completion of operation, the vehicle CAN be powered off manually, the balancing process is completed through the CMU, and the balancing process CAN be stopped through the starting of the vehicle at any time; selecting detailed information and then displaying the average battery voltage, the target battery string number, the target battery voltage and the target battery equalization time; and after the balance is finished, the BMS clears the stored balance information.

In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention; furthermore, unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, as they may be fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that various modifications can be made to the embodiments described in the foregoing embodiments, or some or all of the technical features of the embodiments can be equivalently replaced, and the modifications or the replacements do not make the essence of the corresponding technical solutions depart from the scope of the embodiments of the present invention.