阅读说明：本技术 绝缘电阻测量装置及方法 (Insulation resistance measuring device and method ) 是由 李圣键 于 2019-12-18 设计创作，主要内容包括：本发明涉及一种电池的绝缘电阻测量装置和方法。根据本发明的实施方式的绝缘电阻测量装置包括：第一电阻单元,所述第一电阻单元的一端连接到电池的负极,而另一端接地,并且根据控制选择性地具有第一电阻值或第二电阻值,所述第二电阻值大于第一电阻值；第二电阻单元,所述第二电阻单元的一端连接到所述电池的正极,而另一端接地,并且根据控制选择性地具有第三电阻值或第四电阻值,所述第四电阻值大于所述第三电阻值；电压测量单元,所述电压测量单元用于测量与所述第一电阻单元或所述第二电阻单元的相反端有关的电压；以及绝缘电阻计算单元,所述绝缘电阻计算单元用于通过使用所述第一电阻值至所述第四电阻值和由所述电压测量单元测量的电压来计算所述地与所述电池的所述负极之间的第一绝缘电阻值以及所述地与所述电池的所述正极之间的第二绝缘电阻值。(The invention relates to a device and a method for measuring the insulation resistance of a battery. An insulation resistance measuring apparatus according to an embodiment of the present invention includes: a first resistance unit having one end connected to a negative electrode of the battery and the other end grounded, and selectively having a first resistance value or a second resistance value greater than the first resistance value according to a control; a second resistance unit having one end connected to a positive electrode of the battery and the other end grounded, and selectively having a third resistance value or a fourth resistance value greater than the third resistance value according to a control; a voltage measuring unit for measuring a voltage related to opposite ends of the first resistance unit or the second resistance unit; and an insulation resistance calculation unit for calculating a first insulation resistance value between the ground and the negative electrode of the battery and a second insulation resistance value between the ground and the positive electrode of the battery by using the first to fourth resistance values and the voltage measured by the voltage measurement unit.)

1. An insulation resistance measuring device comprising:

a first resistance unit, one end of which is connected to a positive electrode of a battery and the other end of which is grounded, and which has a first resistance value or a second resistance value selectively according to control, the second resistance value being greater than the first resistance value;

a second resistance unit having one end connected to a negative electrode of the battery and the other end grounded, and optionally having a third resistance value or a fourth resistance value larger than the third resistance value according to control;

a voltage measurement unit configured to measure a voltage related to both ends of the first resistance unit or the second resistance unit; and

an insulation resistance calculation unit configured to calculate a first insulation resistance value between a positive electrode of the battery and the ground and a second insulation resistance value between a negative electrode of the battery and the ground by using the first to fourth resistance values and the voltage measured by the voltage measurement unit.

2. The insulation resistance measurement device according to claim 1, further comprising a voltage distribution unit that is connected in parallel with the first resistance unit or the second resistance unit and includes a plurality of resistors connected in series,

wherein the insulation resistance calculation unit calculates a first insulation resistance value between the positive electrode of the battery and the ground and a second insulation resistance value between the negative electrode of the battery and the ground by using the voltages measured by some of the resistors of the voltage distribution unit as the voltages measured by the voltage measurement unit.

3. The insulation resistance measurement device according to claim 2, wherein the insulation resistance calculation unit has a first insulation resistance measurement mode and a second insulation resistance measurement mode in which an error rate is relatively low in different measurement ranges, and is configured to:

in the first insulation resistance measurement mode, the first insulation resistance value and the second insulation resistance value are calculated using a first resistance value and a third resistance value, and

in the second insulation resistance measurement mode, the first insulation resistance value and the second insulation resistance value are calculated using a second resistance value and a fourth resistance value.

4. The insulation resistance measurement device according to claim 3, wherein, for each of the first insulation resistance value and the second insulation resistance value, the insulation resistance calculation unit determines a measurement range corresponding to the insulation resistance value calculated in the first insulation resistance measurement mode and the insulation resistance value calculated in the second insulation resistance measurement mode, and determines, as an actual insulation resistance value, the insulation resistance value calculated in a measurement mode having a relatively low error rate within the determined measurement range, from among the first insulation resistance measurement mode and the second insulation resistance measurement mode.

5. The insulation resistance measurement device according to claim 3, wherein the first resistance unit is formed as a first resistance unit and a second resistance unit connected in parallel between the positive electrode of the battery and the ground, the first resistance unit being on/off controlled by a first switch, the second resistance unit being on/off controlled by a second switch,

wherein the second resistance unit is formed as a third resistance unit and a fourth resistance unit connected in parallel between the negative electrode of the battery and the ground, the third resistance unit being controlled to be turned on/off by a third switch, and the fourth resistance unit being controlled to be turned on/off by a fourth switch.

6. The insulation resistance measurement device according to claim 5, wherein the third switch and the fourth switch of the second resistance unit are controlled to be off when the first switch or the second switch of the first resistance unit is controlled to be on.

7. The insulation resistance measurement device according to claim 5, wherein the first switch and the second switch of the first resistance unit are controlled to be off when the third switch or the fourth switch of the second resistance unit is controlled to be on.

8. The insulation resistance measurement device according to claim 5, wherein, in the case of the first insulation resistance measurement mode, the first insulation resistance value and the second insulation resistance value are calculated by using voltages measured from some of the resistors of the voltage distribution unit when the first switch is controlled to be on and the second switch to the fourth switch are controlled to be off and voltages measured from some of the resistors of the voltage distribution unit when the third switch is controlled to be on and the first switch, the second switch, and the fourth switch are controlled to be off.

9. The insulation resistance measurement device according to claim 5, wherein, in the case of the second insulation resistance measurement mode, the first insulation resistance value and the second insulation resistance value are calculated by using a voltage measured from some of the resistors of the voltage distribution unit when the second switch is controlled to be on and the first switch, the third switch, and the fourth switch are controlled to be off, and a voltage measured from some of the resistors of the voltage distribution unit when the fourth switch is controlled to be on and the first switch to the third switch are controlled to be off.

10. The insulation resistance measurement device according to claim 1, wherein the first to fourth resistance values are values that change according to a battery or a device in which a battery is mounted.

11. The insulation resistance measurement device according to claim 1, wherein the voltage distribution unit further includes a fifth switch connected in series with a plurality of resistors to be controlled to be turned on/off.

12. The insulation resistance measuring device according to claim 1, wherein the battery is a battery holder, and the ground is a chassis of the battery holder.

13. The insulation resistance measurement device according to claim 3, wherein the first resistance unit includes a first variable resistance unit between the positive electrode of the battery and the ground, the first variable resistance unit being on/off controlled by a first switch and being variable between the first resistance value and the second resistance value,

wherein the second resistance unit includes a second variable resistance unit between the negative electrode of the battery and the ground, the second variable resistance unit being on/off controlled by a third switch and being variable between the third resistance value and the fourth resistance value.

14. An insulation resistance measuring method comprising the steps of:

setting a plurality of insulation resistance measurement modes having relatively low error rates in different measurement ranges to measure the insulation resistance of the battery;

calculating a first insulation resistance value between a positive electrode of the battery and a ground and a second insulation resistance value between a negative electrode of the battery and the ground through each insulation resistance measurement mode;

determining, for each of the first insulation resistance value and the second insulation resistance value, a measurement range corresponding to the insulation resistance value calculated in each insulation resistance measurement mode; and

the insulation resistance value calculated in the measurement mode having a relatively low error rate within the determined measurement range is determined as an actual insulation resistance value.

15. The insulation resistance measurement method according to claim 14, wherein when measuring the insulation resistance, the plurality of insulation resistance measurement modes are changed by changing a resistance value of a first resistance unit and a resistance value of a second resistance unit, one end of the first resistance unit being connected to a positive electrode of the battery, the other end of the first resistance unit being grounded, one end of the second resistance unit being connected to a negative electrode of the battery, the other end of the second resistance unit being grounded.

Technical Field

Cross Reference to Related Applications

This application claims priority to korean patent application No. 10-2019-0000520, filed on 3/1/2019, the entire contents of which are incorporated herein by reference.

Technical Field

The present invention relates to an apparatus and method for measuring insulation resistance of a battery.

Background

In high voltage battery systems, a certain level of insulation must always be maintained to protect the user from the risk of short circuits. Therefore, when diagnosing the battery system, more accurate insulation resistance measurement is required.

In conventional insulation resistance measurement, a distribution resistor is alternately connected to either of the negative and positive electrodes of the battery with respect to ground (e.g., a chassis), and an insulation resistance value is calculated from the measured distribution voltage value.

However, conventionally, since the measurement range within the allowable error range is limited based on the designed distribution resistance value in the case where, for example, the actual insulation resistance value at the measurement terminal of the negative electrode or positive electrode of the battery is larger than the sum of the distribution resistance values designed in advance, the calculated insulation resistance value exceeds the measurement range within the error range, so that there is a problem that the measurement accuracy is low.

Disclosure of Invention

Technical problem

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an insulation resistance measurement apparatus and method which can prevent a decrease in measurement accuracy by calculating insulation resistance in a measurement range within an error range corresponding to an actual insulation resistance value when measuring the insulation resistance of a battery.

Technical scheme

An insulation resistance measuring apparatus according to an embodiment of the present invention includes: a first resistance unit having one end connected to a positive electrode of a battery and the other end grounded, and optionally having a first resistance value or a second resistance value greater than the first resistance value according to a control; a second resistance unit having one end connected to a negative electrode of the battery and the other end grounded, and optionally having a third resistance value or a fourth resistance value greater than the third resistance value according to a control; a voltage measurement unit configured to measure a voltage related to both ends of the first resistance unit or the second resistance unit; and an insulation resistance calculation unit configured to calculate a first insulation resistance value between the positive electrode of the battery and the ground and a second insulation resistance value between the negative electrode of the battery and the ground by using the first to fourth resistance values and the voltage measured by the voltage measurement unit.

In addition, the insulation resistance measuring apparatus according to the embodiment of the present invention further includes a voltage distribution unit connected in parallel with the first resistance unit or the second resistance unit and including a plurality of resistors connected in series. In this case, the insulation resistance calculation unit may calculate a first insulation resistance value between the positive electrode of the battery and the ground and a second insulation resistance value between the negative electrode of the battery and the ground by using the voltages measured by some of the resistors of the voltage distribution unit as the voltages measured by the voltage measurement unit.

The insulation resistance calculation unit has a second insulation resistance measurement mode and a first insulation resistance measurement mode having relatively low error rates in different measurement ranges, calculates a first insulation resistance value and a second insulation resistance value using the first resistance measurement value and the third resistance measurement value in the first insulation resistance measurement mode, and calculates the first insulation resistance value and the second insulation resistance value using the second resistance value and the fourth resistance value in the second insulation resistance measurement mode.

For example, in the case of the first insulation resistance measurement mode, the first insulation resistance value and the second insulation resistance value may be calculated by using the voltage measured from some of the resistors of the voltage distribution unit when the first switch is controlled to be turned ON (ON) and the second to fourth switches are controlled to be turned OFF (OFF) and the voltage measured from some of the resistors of the voltage distribution unit when the third switch is controlled to be turned ON and the first switch, the second switch, and the fourth switch are controlled to be turned OFF.

In addition, in the case of the second insulation resistance measurement mode, the first insulation resistance value and the second insulation resistance value may be calculated by using the voltages measured from some of the resistors of the voltage distribution unit when the second switch is controlled to be on and the first switch, the third switch, and the fourth switch are controlled to be off and the voltages measured from some of the resistors of the voltage distribution unit when the fourth switch is controlled to be on and the first switch to the third switch are controlled to be off.

Further, for each of the first insulation resistance value and the second insulation resistance value, the insulation resistance calculation unit determines a measurement range corresponding to the insulation resistance value calculated in the first insulation resistance measurement mode and the insulation resistance value calculated in the second insulation resistance measurement mode, and determines, as the actual insulation resistance value, the insulation resistance value calculated in a measurement mode having a relatively low error rate within the determined measurement range, from among the first insulation resistance measurement mode and the second insulation resistance measurement mode.

The first resistance unit is formed as a first resistance unit controlled to be turned ON/OFF (ON/OFF) by a first switch and a second resistance unit controlled to be turned ON/OFF by a second switch, which are connected in parallel between the positive electrode of the battery and the ground. For example, when the first switch or the second switch of the first resistance unit is controlled to be turned on, the third switch and the fourth switch of the second resistance unit are controlled to be turned off.

In addition, the second resistance unit is formed as a third resistance unit and a fourth resistance unit connected in parallel between the negative electrode of the battery and the ground, the third resistance unit being on/off controlled by the third switch, and the fourth resistance unit being on/off controlled by the fourth switch. For example, when the third switch or the fourth switch of the second resistance unit is controlled to be turned on, the first switch and the second switch of the first resistance unit are controlled to be turned off.

As another example, the first resistance unit includes a first variable resistance unit that is controlled to be turned on/off by the first switch and can be converted into a first resistance value or a second resistance value between the positive electrode of the battery and the ground, and also the second resistance unit includes a second variable resistance unit that is controlled to be turned on/off by the third switch and can be converted into a third resistance value or a fourth resistance value between the negative electrode of the battery and the ground.

For example, the first to fourth resistance values are values that vary according to the battery or the device in which the battery is mounted.

The voltage distribution unit further includes a fifth switch connected in series with the plurality of resistors to be controlled to be turned on/off.

As one embodiment, the battery is a battery rack (battery rack) and the ground is a chassis of the battery rack.

Further, an insulation resistance measurement method according to an embodiment of the present invention includes: setting a plurality of insulation resistance measurement modes having relatively low error rates in different measurement ranges to measure the insulation resistance of the battery; calculating a first insulation resistance value between the positive electrode of the battery and the ground and a second insulation resistance value between the negative electrode of the battery and the ground through each insulation resistance measurement mode; determining, for each of the first insulation resistance value and the second insulation resistance value, a measurement range corresponding to the insulation resistance value calculated in each insulation resistance measurement mode; and determining the insulation resistance value calculated in the measurement mode having a relatively low error rate within the determined measurement range as an actual insulation resistance value.

Here, when measuring the insulation resistance, the plurality of insulation resistance measurement modes are changed by changing a resistance value of a first resistance unit, one end of which is connected to a positive electrode of the battery and the other end of which is grounded, and a resistance value of a second resistance unit, one end of which is connected to a negative electrode of the battery and the other end of which is grounded.

Advantageous effects

According to the present invention, when measuring the insulation resistance of a battery, it is possible to prevent the measurement accuracy from being lowered by calculating the insulation resistance in the measurement range within the error range corresponding to the actual insulation resistance value. This allows more accurate insulation resistance values to be measured and reported when diagnosing the battery system.

Other effects of the present invention will be further described according to the following examples.

Drawings

Fig. 1 is a block diagram showing the configuration of a battery holder.

Fig. 2 is a block diagram showing the configuration of an insulation resistance measuring apparatus according to an embodiment of the present invention.

Fig. 3 is a diagram schematically showing a circuit configuration of an insulation resistance measurement device according to an embodiment of the present invention.

Fig. 4 is an equivalent circuit of fig. 3.

Fig. 5 is a flowchart illustrating an insulation resistance measurement method according to an embodiment of the present invention.

Fig. 6 (a) and 6 (b) are diagrams for explaining a method of calculating an insulation resistance value in the second insulation resistance measurement mode according to an embodiment of the present invention.

Fig. 7 (a) and 7 (b) are diagrams for explaining a method of calculating an insulation resistance value in the first insulation resistance measurement mode according to an embodiment of the present invention.

Fig. 8 (a) is a table showing a measurement error with respect to an insulation resistance value in the first insulation resistance measurement mode, and fig. 8 (b) is a table showing a measurement error with respect to an insulation resistance value in the second insulation resistance measurement mode.

Fig. 9 is a diagram schematically showing a circuit configuration of an insulation resistance measuring apparatus according to another embodiment of the present invention.

Fig. 10 is a block diagram showing a configuration of an insulation resistance measuring apparatus according to another embodiment of the present invention.

Fig. 11 is a block diagram illustrating a hardware configuration of a battery management system according to an embodiment of the present invention.

Detailed Description

Hereinafter, some embodiments of the present invention will be described in detail by way of exemplary drawings. It should be noted that, when a reference numeral is assigned to a component of each drawing, the same reference numeral refers to the same component although the component is shown on different drawings. In addition, in describing the inventive concept, if it is determined that a detailed description of known configurations or functions obscures a subject matter of the inventive concept, the detailed description of the known configurations or functions will be omitted.

First, the configuration of the battery holder will be briefly described with reference to fig. 1. Fig. 1 is a block diagram showing the configuration of a battery holder.

As shown in fig. 1, for example, a battery holder R applicable to a high-voltage battery system includes: a battery C that can be charged and discharged, in which one or more battery modules (e.g., battery packs) are connected in series or in parallel; a switching unit 2 connected in series to a + terminal (positive electrode) side or a-terminal (negative electrode) side of the battery C to control a charge/discharge current flow of the battery C; and a battery management system 3 (hereinafter, also referred to as BMS), the battery management system 3 monitoring a voltage, a current, a temperature, etc. of the battery and controlling and managing the voltage, the current, the temperature, etc. of the battery to prevent overcharge and overdischarge.

Here, the switching unit 2 is a switching element for controlling the flow of current for charging or discharging the battery C, and may be a configuration provided essentially for the operation of the battery holder R.

In addition, the BMS 3 may monitor voltage, current, temperature, etc. as the state of the battery C. The BMS 3 may include a circuit that receives values obtained by measuring various parameters such as voltage, current, and temperature and processes the received values.

In addition, such a configuration of the battery holder R is provided in the chassis 4 as a housing, and the chassis 4 is grounded. Each component of the battery holder R (i.e., the battery C, the switching unit 2, the BMS 3, and the chassis 4) is designed to be insulated therebetween such that an insulation resistance exists between the battery and the chassis.

Since the configurations of the battery rack R and the BMS 3 are known configurations, a more detailed description thereof will be omitted.

Next, an insulation resistance measurement apparatus according to an embodiment of the present invention will be described with reference to fig. 2 to 4. Fig. 2 is a block diagram showing the configuration of an insulation resistance measuring apparatus according to an embodiment of the present invention. Fig. 3 is a diagram schematically showing a circuit configuration of an insulation resistance measurement device according to an embodiment of the present invention. Fig. 4 is an equivalent circuit of fig. 3.

As shown in fig. 2, the insulation resistance measuring apparatus according to an embodiment of the present invention may include a first resistance unit 10, a second resistance unit 20, a voltage measuring unit 30, and an insulation resistance calculating unit 40.

The first resistance unit 10 has a configuration in which one end is connected to the positive electrode of the battery C and the other end is grounded, and the first resistance unit 10 may alternatively have a first resistance value or a second resistance value, which is greater than the first resistance value, under control.

For example, as shown in fig. 3, the first resistance unit 10 may have the following circuit configuration: in the circuit configuration, a first resistance value unit controlled to be turned on/off by the first switch 11 and a second resistance value unit controlled to be turned on/off by the second switch 13 are connected in parallel between the positive electrode of the battery C and the ground. For example, the first switch 11 and the second switch 13 may be controlled by the insulation resistance calculation unit 40. In this way, the first resistance unit 10 can selectively have the first resistance value or the second resistance value by on/off control of the first switch 11 and the second switch 13.

Here, the first resistance value unit may be a resistance unit having a first resistance value, and may include, for example, a plurality of resistors (five R1) and the first switch 11 connected in series. In the same manner, the second resistance value unit may be a resistance unit having a second resistance value, and may include, for example, a plurality of resistors (five R1 and two R2) and the second switch 13 connected in series. The first resistance value and the second resistance value are values set assuming that the actual insulation resistance value is high or low. Although fig. 3 illustrates that the first resistance value cell and the second resistance value cell share a plurality of resistances (five R1), as long as the first resistance value cell and the second resistance value cell have the first resistance value and the second resistance value, respectively, they may not be shared and different resistors may be designed. In addition, although the first resistance value unit and the second resistance value unit are shown to be formed of a plurality of resistors, these resistors may be designed as one or more resistors as long as they have the set resistance values.

For example, when the first switch 11 or the second switch 13 of the first resistance unit 10 is controlled to be turned on, the third switch 21 and the fourth switch 23 of the second resistance unit 20 are controlled to be turned off.

In addition, in the second resistance unit 20, one end is connected to the negative electrode of the battery C and the other end is grounded, and may optionally have a third resistance value or a fourth resistance value, which is greater than the third resistance value.

For example, as shown in fig. 3, the second resistance unit 20 may have the following circuit configuration: in the circuit configuration, a third resistance value unit, which is controlled to be turned on/off by the third switch 21, and a fourth resistance value unit, which is controlled to be turned on/off by the fourth switch 23, are connected in parallel between the negative electrode of the battery C and the ground. For example, the third switch 21 and the fourth switch 23 may be controlled by the insulation resistance calculation unit 40. In this way, the second resistance unit 20 can selectively have the third resistance value or the fourth resistance value by on/off control of the third switch 21 and the fourth switch 23.

Here, the third resistance value unit may be a resistance unit having a third resistance value, and may include, for example, a plurality of resistors (five R1) and the third switch 21 connected in series. In the same manner, the fourth resistance value unit may be a resistance unit having a fourth resistance value, and may include, for example, a plurality of resistors (five R1 and two R2) and the fourth switch 23 connected in series. The third resistance value and the fourth resistance value are values set assuming that the actual insulation resistance value is high or low, and may be the same as the first resistance value and the second resistance value, respectively. Although fig. 3 illustrates that the third resistance value cell and the fourth resistance value cell share a plurality of resistors (five R1), they may not be shared and different resistors may be designed as long as the third resistance value cell and the fourth resistance value cell have the third resistance value and the fourth resistance value, respectively. In addition, although the third resistance value unit and the fourth resistance value unit are shown to be formed of a plurality of resistors, these resistors may be designed as one or more resistors as long as they have the set resistance values.

For example, when the third switch 21 or the fourth switch 23 of the second resistance unit 20 is controlled to be turned on, the first switch 11 and the second switch 13 of the first resistance unit 10 are controlled to be turned off.

Here, the first to fourth resistance values may be changed according to the battery C or the device in which the battery C is mounted.

As one embodiment, the battery C may be a battery stand, and the ground may be a chassis of the battery stand.

The voltage measuring unit 30 is a configuration for measuring a voltage of each part of the circuit, and may measure a voltage related to both ends of the first resistance unit 10 or the second resistance unit 20. Specifically, in order to measure the insulation resistance of the battery, for example, the voltage may be measured according to some resistances of the voltage distribution unit 50 described later.

In addition, the insulation resistance calculation unit 40 is configured to calculate the insulation resistance of the battery using the first to fourth resistance values and the voltage measured by the voltage measurement unit 30, and may calculate, for example, a first insulation resistance value between the positive electrode of the battery C and the ground and a second insulation resistance value between the negative electrode of the battery C and the ground. In one example, the insulation resistance calculation unit 40 may be implemented, for example, as a microcontroller unit (MCU).

The voltage distribution unit 50 is configured to distribute a voltage at a predetermined voltage distribution ratio during insulation resistance measurement, and for example, as shown in fig. 3, the voltage distribution unit 50 may be connected in parallel with the second resistance unit 20, and the voltage distribution unit 50 may include a plurality of resistors (four R3 and one R4) connected in series. At this time, the voltage measuring unit 30 may measure the voltage from both ends of the resistor R4. Further, the voltage division ratio is determined by a resistance ratio between a plurality of resistors connected in series, and is set to facilitate voltage measurement.

In addition, the voltage distribution unit 50 is connected in parallel with the second resistance unit 20 in fig. 3, but may be designed to be connected in parallel with the first resistance unit 10. In addition, as shown in fig. 3, to be separated from the circuit, the voltage distribution unit 50 may further include a fifth switch 55, the fifth switch 55 being connected in series with a plurality of resistors (four R3 and one R4) to be on/off controlled. In addition, as shown in fig. 3, a resistor R5 and a capacitor C1 for circuit protection such as noise removal may also be provided between the voltage distribution unit 50 and the insulation resistance calculation unit 40, and in addition, a switch 65 may also be provided between the first resistance unit 10 and the second resistance unit 20 and the ground.

For example, the circuit configuration of the insulation resistance measuring apparatus in fig. 3 may be represented by an equivalent circuit as shown in fig. 4. That is, in the first resistance unit 10, the first resistance value may be represented by Rg and the second resistance value may be represented by Rg, and in the second resistance unit 20, the third resistance value may be represented by Rf and the fourth resistance value may be represented by Rf. In addition, the plurality of resistors of the voltage distribution unit 50 may be represented by Re1 and Re2, and the sum of the plurality of resistors may be represented by Re.

Accordingly, the insulation resistance calculation unit 40 can calculate the first insulation resistance value RP between the positive pole of the battery C and the ground and the second insulation resistance value RN between the negative pole of the battery C and the ground using the voltages measured by the voltage measurement unit 30 from some of the resistors Re2 of the voltage distribution unit 50.

For example, the insulation resistance calculation unit 40 is provided with a plurality of insulation resistance measurement modes (e.g., a first insulation resistance measurement mode and a second insulation resistance measurement mode) having relatively low error rates in different measurement ranges, so that the insulation resistance calculation unit 40 calculates the first insulation resistance value RP and the second insulation resistance value RN using the first resistance value Rg and the third resistance value Rf in the first insulation resistance measurement mode, and calculates the first insulation resistance value RP and the second insulation resistance value RN using the second resistance Rg and the fourth resistance value Rf in the second insulation resistance measurement mode.

Specifically, in the case of the first insulation resistance measurement mode, the first insulation resistance value RP and the second insulation resistance value RN may be calculated by using the voltage measured from some of the resistors Re2 of the voltage distribution unit 50 when the first switch 11 is controlled to be on and the second switch 13, the third switch 21, and the fourth switch 23 are controlled to be off and the voltage measured from some of the resistors Re2 of the voltage distribution unit 50 when the third switch 21 is controlled to be on and the first switch 11, the second switch 13, and the fourth switch 23 are controlled to be off.

In a similar manner, in the case of the second insulation resistance measurement mode, the first insulation resistance value RP and the second insulation resistance value RN may be calculated by using the voltage measured from some of the resistors Re2 of the voltage distribution unit 50 when the second switch 13 is controlled to be on and the first switch 11, the third switch 21, and the fourth switch 23 are controlled to be off and the voltage measured from some of the resistors Re2 of the voltage distribution unit 50 when the fourth switch 23 is controlled to be on and the first switch 11, the second switch 13, and the third switch 21 are controlled to be off.

In this way, the insulation resistance calculation unit 40 can calculate the first insulation resistance value and the second insulation resistance value in the plurality of insulation resistance measurement modes, respectively.

Here, when measuring the insulation resistance, the plurality of insulation resistance measurement modes are modes that are changed by changing the resistance value of the first resistance unit 10 having one end connected to the positive pole of the battery and the other end grounded and the resistance value of the second resistance unit 20 having one end connected to the negative pole of the battery and the other end grounded, and for example, when the actual insulation resistance is low, the measurement range of the first insulation resistance measurement mode has a relatively low error rate, and when the actual insulation resistance is high, the measurement range of the second insulation resistance measurement mode has a relatively low error rate.

In addition, the insulation resistance calculation unit 40 determines one insulation resistance value among the calculated insulation resistance values as an actual insulation resistance value.

For example, for each of the first insulation resistance value and the second insulation resistance value, a measurement range corresponding to the insulation resistance value calculated in the first insulation resistance measurement mode and the insulation resistance value calculated in the second insulation resistance measurement mode is determined, and the insulation resistance value calculated in the measurement mode having a relatively low error rate within the determined measurement range, among the first insulation resistance measurement mode and the second insulation resistance measurement mode, is determined as the actual insulation resistance value.

In one example, the insulation resistance measuring apparatus according to the embodiment of the present invention may be implemented as a part of a function of a battery management system of a battery rack, or may be implemented as a separate device.

According to the present invention as described above, when measuring the insulation resistance of a battery, by calculating the insulation resistance within the measurement range within the error range corresponding to the actual insulation resistance value (i.e., within the measurement range having a relatively low error rate), it is possible to prevent the measurement accuracy from being lowered. This allows more accurate insulation resistance values to be measured and reported when diagnosing the battery system.

Next, an insulation resistance measurement method according to an embodiment of the present invention will be described with reference to fig. 5 to 7. Fig. 5 is a flowchart illustrating an insulation resistance measurement method according to an embodiment of the present invention. Fig. 6 (a) and 6 (b) are diagrams for explaining a method of calculating an insulation resistance value in the second insulation resistance measurement mode according to an embodiment of the present invention. Fig. 7 (a) and 7 (b) are diagrams for explaining a method of calculating an insulation resistance value in the first insulation resistance measurement mode according to an embodiment of the present invention.

As shown in fig. 5, first, in order to measure the insulation resistance of the battery C, the insulation resistance measuring method according to the embodiment of the present invention sets a plurality of insulation resistance measuring modes having a relatively low error rate in different measuring ranges (S10).

As described above, when measuring the insulation resistance, the plurality of insulation resistance measurement modes are modes that are changed by changing the resistance value of the first resistance unit 10, one end of which is connected to the positive electrode of the battery C and the other end of which is grounded, and the resistance value of the second resistance unit 20, one end of which is connected to the negative electrode of the battery C and the other end of which is grounded.

For example, the plurality of insulation resistance measurement modes may include a first insulation resistance measurement mode having a relatively low error rate when in a measurement range where the actual insulation resistance has a low value and a second insulation resistance measurement mode having a relatively low error rate when in a measurement range where the actual insulation resistance value has a high value.

Next, a first insulation resistance value RP between the positive electrode of the battery C and the ground and a second insulation resistance value RN between the negative electrode of the battery C and the ground are calculated by the respective insulation resistance measurement modes (S20).

For example, as the second insulation resistance measurement mode, as shown in (a) of fig. 6, when the first resistance unit 10 has the second resistance value RG (i.e., when the second switch 13 is controlled to be turned on and the first switch 11, the third switch 21, and the fourth switch 23 are controlled to be turned off), equation 1 of the measured voltage a can be derived from the equivalent circuit.

[ equation 1]

Here, RN is the second insulation resistance value, RE is the sum of the resistance values of the voltage distribution units, RP is the first insulation resistance value, C is the voltage value of the battery, and D is the voltage distribution ratio for measuring the voltage distribution units. Here, the measured voltage a is, for example, a voltage measured from the resistor Re2 of the voltage distribution unit.

In addition, as the second insulation resistance measurement mode, as shown in (B) of fig. 6, when the second resistance unit 20 has the fourth resistance value RG (i.e., when the fourth switch 23 is controlled to be turned on and the first switch 11, the second switch 13, and the third switch 21 are controlled to be turned off), equation 2 of the measured voltage B can be derived from the equivalent circuit.

[ equation 2]

In this case, when (RN// RE) is X, equation 1 may be expressed as equation 3, and equation 2 may be expressed as equation 4.

[ equation 3]

[ equation 4]

Here, if equation 3 is summarized as X, equation 3 may be expressed as equation 5, and if equation 4 is summarized as X, equation 4 may be expressed as equation 6.

[ equation 5]

[ equation 6]

Therefore, by using equations 5 and 6 as simultaneous equations, X can be eliminated to derive the first insulation resistance value RP, as shown in equation 7.

[ equation 7]

Subsequently, by substituting X ═ (RN// RE) into equation 5, the second insulation resistance value RN can be derived as equation 8.

[ equation 8]

In this way, the first insulation resistance value and the second insulation resistance value can be calculated in the second insulation resistance measurement mode.

In the same manner as the first insulation resistance measurement mode, as shown in (a) of fig. 7, when the first resistance unit 10 has the first resistance value Rg (i.e., when the first switch 11 is controlled to be turned on and the second switch 13, the third switch 21, and the fourth switch 23 are controlled to be turned off), an equation of the voltage measured from the equivalent circuit is derived, and as shown in (b) of fig. 7, when the second resistance unit 20 has the third resistance value Rf (i.e., when the third switch 21 is controlled to be turned on and the first switch 11, the second switch 13, and the fourth switch 23 are controlled to be turned off), an equation of the measured voltage may be derived from the equivalent circuit to calculate the first insulation resistance value and the second insulation resistance value.

Returning to fig. 5, for each of the calculated first and second insulation resistance values, a measurement range corresponding to the insulation resistance value calculated in each insulation resistance measurement mode is determined (S30).

Subsequently, the insulation resistance value calculated in the measurement mode having a relatively low error rate within the determined measurement range is determined as an actual insulation resistance value (S40).

The measurement error in each insulation resistance measurement mode can be obtained by repeating the experiment, as shown in fig. 8.

For example, (a) of fig. 8 is a table showing a measurement error (%) with respect to an insulation resistance value in the first insulation resistance measurement mode, and (b) of fig. 8 is a table showing a measurement error with respect to an insulation resistance value in the second insulation resistance measurement mode.

As shown in (a) of fig. 8, it can be seen that, in the first insulation resistance measurement mode, an error of a relatively small insulation resistance value is lower than an error of a relatively large insulation resistance value. Therefore, the measurement range of the first insulation resistance measurement mode may be set to a range having a relatively low error rate, for example, a range of 10,000k ohms or less.

In addition, as shown in (b) of fig. 8, it can be seen that in the second insulation resistance measurement mode, an error of a relatively large insulation resistance value is lower than an error of a relatively small insulation resistance value. Therefore, the measurement range of the second insulation resistance measurement mode may be set to a range having a relatively low error rate, for example, a range of 10,000k ohms or more.

For example, when the first or second insulation resistance values calculated in the first and second insulation resistance measurement modes are all 10,000k ohms or less, it may be determined in operation S30 of fig. 5 that the corresponding measurement range corresponds to a measurement range of the relatively low first insulation resistance measurement mode, and the insulation resistance value calculated in the first insulation resistance measurement mode may be determined as an actual insulation resistance value in operation S40 of fig. 5.

Therefore, in order to accurately measure a relatively low insulation resistance value, the first insulation resistance measurement mode is used, and in order to accurately measure a relatively high insulation resistance value, the second insulation resistance measurement mode is used.

When the insulation resistance of the battery C is measured in this manner, by calculating the insulation resistance in the measurement range corresponding to the actual insulation resistance value, it is possible to prevent the measurement accuracy from being lowered.

On the other hand, the first resistance unit 10 and the second resistance unit 20 of the insulation resistance measurement device have been described in the above description as having a parallel circuit structure using a plurality of switches and a plurality of resistors so as to have a plurality of resistance values as shown in fig. 3, but they may be designed using variable resistors, for example, as shown in fig. 9.

Fig. 9 is a diagram schematically showing a circuit configuration of an insulation resistance measuring apparatus according to another embodiment of the present invention.

As shown in fig. 9, in the insulation resistance measuring apparatus according to another embodiment of the present invention, the first resistance unit 10a may include a first variable resistance unit R1a, the first variable resistance unit R1a being turned on/off by the first switch 11 and being convertible to a first resistance value or a second resistance value between the positive electrode of the battery C and the ground, and also, the second resistance unit 20a may include a second variable resistance unit R2a, the second variable resistance unit R2a being turned on/off by the third switch 21a and being convertible to a third resistance value or a fourth resistance value between the negative electrode of the battery and the ground. Other configurations are as described above.

In the above description, the voltage distribution unit 50 of the insulation resistance measurement device is connected in parallel with the second resistance unit 20 as shown in fig. 2, but for example, the voltage distribution unit 50 of the insulation resistance measurement device may be designed to be connected in parallel with the first resistance unit 10 as shown in fig. 10.

Fig. 10 is a block diagram showing a configuration of an insulation resistance measuring apparatus according to another embodiment of the present invention.

As shown in fig. 10, the voltage distribution unit 50a may be designed to have a parallel structure with the first resistance unit 10 between the positive electrode of the battery C and the ground. Other configurations are as described above.

As another embodiment, the insulation resistance measuring method according to the embodiment of the present invention described above may be implemented as a program stored in a recording medium for performing each operation, and the corresponding program is stored in a memory of the BMS of the battery rack and may be executed by the MCU. In other words, the method of the present invention may be written in a computer program. Also, codes and code segments constituting the program can be easily inferred by computer programmers in the art. Further, the created program is stored in a computer-readable recording medium (information storage medium), and can be read and executed by a computer to implement the method of the present invention. The recording medium may then include any type of computer-readable recording medium. The recording medium may be provided separately from the MCU or may be configured integrally with the MCU.

For example, the BMS of the battery stand of the present invention may be implemented as shown in fig. 11. Fig. 11 is a block diagram illustrating a hardware configuration of a Battery Management System (BMS) according to an embodiment of the present invention.

As shown in fig. 11, the battery management system 300 may include: an MCU 310 for controlling various processes and various configurations; a memory 320 for recording an operating system program and various programs (for example, an insulation resistance measurement program of a battery); an input/output interface 330 providing an input interface and an output interface between the battery and/or the switching unit; and a communication interface 340 capable of communicating with the outside through a wired or wireless communication network. As described above, the computer program according to the present invention may be recorded in the memory 320 and processed by the microcontroller 310 to be implemented as a module for executing the respective functional blocks shown in fig. 2.

Although the present invention has been described above by way of limited embodiments and drawings, the present invention is not limited thereto, and it is apparent to those skilled in the art that the present invention can be implemented in various ways within the technical spirit of the present invention and the equivalent scope of the claims to be described below.