Passive equalization capability testing method, system, electronic device and readable medium

Abstract

The purpose of the present invention is to provide a test method, system, electronic device and readable medium for passive balancing capability, including: discharging a first battery cell so that the difference between the state of charge of the first battery cell and the state of charge of the second battery cell is greater than a preset threshold value; charging a target power battery pack with a preset charging rate at a constant current, and recording the first terminal voltage data of the target power battery pack after it is fully charged; after the target power battery pack continuously runs a preset test cycle under a preset working condition, charging the target power battery pack with a constant current at a preset charging rate again, and recording the second terminal voltage data of the target power battery pack after it is fully charged; based on the first terminal voltage data and the second terminal voltage data, determining the passive balancing capability of the battery management system to be tested. The present invention alleviates the technical problem that it is difficult to quantify the balancing capability in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of passive equalization capability testing of a battery management system, and in particular to a passive equalization capability testing method, system, electronic equipment and readable medium. Background Art

[0002] To ensure the consistency of the power battery system, the battery management system (BMS) needs to have a passive balancing function. Passive balancing principle: When the state of charge (SOC) difference (voltage difference) between single cells exceeds the set threshold, the BMS discharges the battery with high SOC (single cell voltage) through the discharge resistor, thereby reducing the voltage difference between the high SOC state battery and the low SOC state battery, achieving the purpose of balancing between the cells.

[0003] Because the control logic of BMS to control passive balancing is complex and the passive balancing current is small, the passive balancing capability of BMS is difficult to quantify. Therefore, although BMS has passive balancing function, its balancing capability may not necessarily match the needs of the product itself.

[0004] When the balancing capacity of the BMS does not meet the needs of the product itself, the pressure difference of the product will gradually increase over time, the vehicle's range will decrease accordingly, and eventually cause quality problems. After-sales costs will increase and affect the reputation of the company's products.

[0005] GB / T 38661-2020 "Technical Conditions for Battery Management Systems for Electric Vehicles" mentions a test method for equalization function without clear acceptance criteria. When capacity is used as the basis for judgment, it will introduce errors due to capacity attenuation during the test, resulting in unreliable test results. Summary of the invention

[0006] In view of this, an object of the present invention is to provide a method, system, electronic device and readable medium for testing passive equalization capability, so as to alleviate the technical problem in the prior art that the equalization capability is difficult to quantify.

[0007] In a first aspect, an embodiment of the present invention provides a method for testing passive balancing capability, which is applied to a battery management system to be tested, comprising: discharging a first battery cell so that the difference between the state of charge of the first battery cell and the state of charge of a second battery cell is greater than a preset threshold value; the first battery cell is a string of battery cells in a target power battery pack, the second battery cell is a string of battery cells with the lowest state of charge value among the battery cells in the target power battery pack other than the first battery cell, and the target power battery pack is a battery pack controlled by the battery management system to be tested; constant current charging the target power battery pack at a preset charging rate, and recording first terminal voltage data of the target power battery pack after full charging; after the target power battery pack continuously runs a preset test cycle under preset working conditions, constant current charging the target power battery pack again at the preset charging rate, and recording second terminal voltage data of the target power battery pack after full charging; based on the first terminal voltage data and the second terminal voltage data, determining the passive balancing capability of the battery management system to be tested.

[0008] Furthermore, before discharging the first battery cell, the method further includes: determining the sum of the balancing start threshold of the battery management system to be tested and the rated balancing capacity of the battery management system to be tested as the preset threshold.

[0009] Further, based on the first terminal voltage data and the second terminal voltage data, the passive balancing capability of the battery management system to be tested is determined, including: based on the first terminal voltage data, determining that the maximum state of charge difference of the target power battery group before running a preset test cycle is a first state of charge difference; based on the second terminal voltage data, determining that the maximum state of charge difference of the target power battery group after running a preset test cycle is a second state of charge difference; and determining the difference between the first state of charge difference and the second state of charge difference as the passive balancing capability of the battery management system to be tested.

[0010] Further, the first terminal voltage data includes the charging terminal voltage value corresponding to each string of battery cells of the target power battery pack before running the preset test cycle; based on the first terminal voltage data, determining the maximum state of charge difference of the target power battery pack before running the preset test cycle as the first state of charge difference, including: determining the highest voltage value in the first terminal voltage data as the first voltage value, and determining the lowest voltage value in the first terminal voltage data as the second voltage value; based on a preset correspondence table, converting the first voltage value into a first state of charge value, and converting the second voltage value into a second state of charge value; the preset correspondence table is a correspondence table between the state of charge value and the voltage value of each string of battery cells in the target power battery pack; and determining the difference between the first state of charge value and the second state of charge value as the first state of charge difference.

[0011] Further, the second terminal voltage data includes the charging terminal voltage value corresponding to each string of battery cells of the target power battery pack after running a preset test cycle; based on the second terminal voltage data, determining the maximum state of charge difference of the target power battery pack after running a preset test cycle as the second state of charge difference, including: determining the highest voltage value in the second terminal voltage data as a third voltage value, and determining the lowest voltage value in the second terminal voltage data as a fourth voltage value; based on a preset correspondence table, converting the third voltage value into a third state of charge value, and converting the fourth voltage value into a fourth state of charge value; the preset correspondence table is a correspondence table between the state of charge value and the voltage value of each string of battery cells in the target power battery pack; determining the difference between the third state of charge value and the fourth state of charge value as the second state of charge difference.

[0012] Furthermore, the preset charging rate is not higher than 0.2C.

[0013] Furthermore, the preset charging rate is any value between 0.05C and 0.1C.

[0014] In a second aspect, an embodiment of the present invention further provides a passive balancing capability test system, which is applied to a battery management system to be tested, and includes: a discharge module, a first recording module, a second recording module and a determination module; wherein the discharge module is used to discharge a first battery cell so that the difference between the state of charge of the first battery cell and the state of charge of the second battery cell is greater than a preset threshold value; the first battery cell is a string of battery cells in a target power battery pack, the second battery cell is a string of battery cells with the lowest state of charge value among the battery cells in the target power battery pack except the first battery cell, and the target power battery pack is the battery to be tested A battery pack controlled by a management system; the first recording module is used to perform constant current charging on the target power battery pack at a preset charging rate, and record the first terminal voltage data of the target power battery pack after it is fully charged; the second recording module is used to perform constant current charging on the target power battery pack again at the preset charging rate after the target power battery pack continuously runs a preset test cycle under preset working conditions, and record the second terminal voltage data of the target power battery pack after it is fully charged; the determination module is used to determine the passive balancing capability of the battery management system to be tested based on the first terminal voltage data and the second terminal voltage data.

[0015] In a third aspect, an embodiment of the present invention further provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method described in the first aspect when executing the computer program.

[0016] In a fourth aspect, an embodiment of the present invention further provides a computer-readable medium having a non-volatile program code executable by a processor, wherein the program code enables the processor to execute the method described in the first aspect.

[0017] The purpose of the present invention is to provide a test method, system, electronic device and readable medium for passive balancing capability. By taking the charging terminal voltage value of the power battery pack before and after the test as an acceptance indicator, the test results are made more accurate, and the quantitative results of the passive balancing capability of the battery management system are made clearer, thereby alleviating the technical problem in the prior art that the balancing capability is difficult to quantify. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A flowchart of a method for testing passive balancing capability provided by an embodiment of the present invention;

[0020] Figure 2 A schematic diagram of a balancing capability acceptance provided by an embodiment of the present invention;

[0021] Figure 3 A schematic diagram of a passive balancing capability testing system provided by an embodiment of the present invention;

[0022] Figure 4 A schematic diagram of a determination module provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Embodiment 1:

[0025] Figure 1 FIG. 1 is a flow chart of a method for testing passive balancing capability according to an embodiment of the present invention, and the method is applied to a battery management system to be tested. Figure 1 As shown, the method specifically comprises the following steps:

[0026] Step S102, discharging the first battery cell so that the difference between the state of charge of the first battery cell and the state of charge of the second battery cell is greater than a preset threshold; the first battery cell is a string of battery cells in a target power battery pack, the second battery cell is a string of battery cells with the lowest state of charge value among the battery cells in the target power battery pack except the first battery cell, and the target power battery pack is a battery pack controlled by the battery management system to be tested.

[0027] In the embodiment of the present invention, before the test, the SOC difference between a string of cells and the remaining cells in the target power battery pack needs to be widened, and the way to widen the SOC difference is to discharge a string of cells separately.

[0028] Step S104, constant current charging is performed on the target power battery pack at a preset charging rate, and the first terminal voltage data of the target power battery pack is recorded after it is fully charged. The first terminal voltage data includes the charging terminal voltage value corresponding to each battery cell string of the target power battery pack before running the preset test cycle.

[0029] Step S106, after the target power battery pack continuously runs the preset test cycle under the preset working condition, the target power battery pack is again charged with a constant current at a preset charging rate, and the second terminal voltage data of the target power battery pack is recorded after it is fully charged. The second terminal voltage data includes the charging terminal voltage value corresponding to each string of battery cells of the target power battery pack after running the preset test cycle. Preferably, the preset test cycle is one month.

[0030] In the embodiment of the present invention, the preset working condition can be formulated according to the actual application scenario. For example, when the vehicle is used in the taxi operation market, it is necessary to evaluate the actual daily average mileage of the operation according to the vehicle operation situation and convert it into the number of cycles of the Chinese working condition n. For example, if the preset test period is set to one month, the preset working condition will be operated for n times of the Chinese working condition cycle every day for one month.

[0031] Step S108: determining the passive balancing capability of the battery management system to be tested based on the first terminal voltage data and the second terminal voltage data.

[0032] The purpose of the present invention is to provide a test method for passive balancing capability. By taking the charging terminal voltage value of the power battery pack before and after the test as the acceptance index, the test result is made more accurate, and the quantitative result of the passive balancing capability of the battery management system is clearer, thereby alleviating the technical problem in the prior art that the balancing capability is difficult to quantify.

[0033] In the embodiment of the present invention, the preset threshold value needs to be set before the test. Specifically, the sum of the equalization start threshold value of the battery management system to be tested and the rated equalization capacity of the battery management system to be tested is determined as the preset threshold value. For example, if the threshold value for turning on the equalization function of the battery management system to be tested (i.e., the equalization start threshold value) is SOC difference ≥ 5%, and the acceptance index of the rated equalization capacity is monthly equalization capacity ≥ 3% SOC, then the preset threshold value is set to 8% SOC.

[0034] Optionally, step S108 further includes the following steps:

[0035] Step S1081: Based on the first terminal voltage data, determine that the maximum state of charge difference of the target power battery pack before running a preset test cycle is a first state of charge difference.

[0036] Specifically, determining the highest voltage value in the first terminal voltage data as the first voltage value, and determining the lowest voltage value in the first terminal voltage data as the second voltage value;

[0037] Based on a preset correspondence table, the first voltage value is converted into a first state of charge value, and the second voltage value is converted into a second state of charge value; the preset correspondence table is a correspondence table between the state of charge value and the voltage value of each string of battery cells in the target power battery pack;

[0038] A difference between the first state of charge value and the second state of charge value is determined as a first state of charge difference.

[0039] Step S1082: Based on the second terminal voltage data, determine that the maximum state of charge difference of the target power battery pack after running a preset test cycle is a second state of charge difference.

[0040] Specifically, determining the highest voltage value in the second terminal voltage data to be the third voltage value, and determining the lowest voltage value in the second terminal voltage data to be the fourth voltage value;

[0041] Based on a preset correspondence table, converting the third voltage value into a third state of charge value, and converting the fourth voltage value into a fourth state of charge value;

[0042] A difference between the third state of charge value and the fourth state of charge value is determined as a second state of charge difference.

[0043] Step S1083: Determine the difference between the first state of charge difference and the second state of charge difference as the passive balancing capability of the battery management system to be tested.

[0044] In an embodiment of the present invention, there is a one-to-one correspondence between the voltage value of the battery cell in the target power battery pack and the SOC, and this relationship can be obtained from a preset correspondence table; by converting the voltage value into the SOC value, and then obtaining the passive balancing capability of the battery management system to be tested, the acceptance index can be made clearer.

[0045] In an optional implementation of the embodiment of the present invention, step S108 may also be implemented by the following steps:

[0046] First, determine the difference between the highest voltage value and the lowest voltage value in the first terminal voltage data to obtain the first voltage difference; then determine the difference between the highest voltage value and the lowest voltage value in the second terminal voltage data to obtain the second voltage difference; finally, subtract the first voltage difference from the second voltage difference to obtain the target voltage difference. The target voltage difference can be used as an acceptance indicator for the passive balancing capability of the battery management system to be tested, or the target voltage difference can be converted into a target SOC difference based on the corresponding relationship between the voltage difference and the SOC difference, and then the target SOC difference can be used as the passive balancing capability of the battery management system to be tested.

[0047] Optionally, Figure 2 FIG. 1 is a schematic diagram of a balancing capability acceptance provided according to an embodiment of the present invention. Figure 2 As shown, the horizontal axis is the serial number of each battery cell string of the target power battery pack, the vertical axis is the relative value of the voltage value of each battery cell string, and the two curves are respectively the curve of the first terminal voltage data and the curve of the second terminal voltage data; Figure 2 The change in the lowest voltage values ​​of the two curves can show the passive balancing ability of the battery tube system under test.

[0048] In the embodiment of the present invention, before and after the test of the passive balancing ability of the battery management system to be tested, the battery needs to be fully charged with a small constant current. The embodiment of the present invention selects small current charging to reduce the error caused by the change of the internal resistance of the power battery. The terminal voltage data of the charge is selected instead of the static voltage data as the basis for judgment because the static pressure difference data of the lithium iron phosphate battery will introduce a larger error. Specifically, the preset charging rate is not higher than 0.2C.

[0049] Preferably, in the embodiment of the present invention, the preset charging rate is any value between 0.05C and 0.1C.

[0050] In an embodiment of the present invention, the passive balancing capability of the battery management system to be tested can be tested through the above-mentioned test method, and the passive balancing capability of the battery management system to be tested can be finally obtained. Then, it is possible to evaluate whether the passive balancing capability of the battery management system to be tested can meet the product performance requirements based on the maximum monthly self-discharge rate of the target power battery. For example, if the maximum monthly self-discharge rate of a single cell of the target power battery is 3% SOC, then the BMS monthly balancing capability design index needs to be ≥3% SOC, that is, the passive balancing capability of the battery management system to be tested needs to be ≥3% SOC to meet the product performance requirements.

[0051] From the above description, it can be seen that the present invention provides a test method for passive balancing capability, which uses the battery voltage or voltage difference before and after the test as an acceptance indicator, so that the acceptance criteria are clear and the test results are more accurate; various working conditions can be simulated according to needs to ensure that the passive balancing capability of the BMS can meet the performance requirements of the product; by setting different test cycles, the test results can be less random and more accurate.

[0052] Embodiment 2:

[0053] Figure 3 is a schematic diagram of a passive balancing capability testing system provided according to an embodiment of the present invention, the system being applied to a battery management system to be tested. Figure 3 As shown, the system includes: a discharging module 10 , a first recording module 20 , a second recording module 30 and a determining module 40 .

[0054] Specifically, the discharge module 10 is used to discharge the first battery cell so that the difference between the state of charge of the first battery cell and the state of charge of the second battery cell is greater than a preset threshold value; the first battery cell is a string of battery cells in a target power battery pack, and the second battery cell is a string of battery cells with the lowest state of charge value among the battery cells in the target power battery pack except the first battery cell, and the target power battery pack is a battery pack controlled by the battery management system to be tested.

[0055] Specifically, the sum of the balancing start threshold of the battery management system to be tested and the rated balancing capability of the battery management system to be tested is determined as the preset threshold.

[0056] The first recording module 20 is used to perform constant current charging on the target power battery pack at a preset charging rate, and record the first terminal voltage data of the target power battery pack after it is fully charged. The first terminal voltage data includes the charging terminal voltage value corresponding to each string of battery cells of the target power battery pack before running the preset test cycle.

[0057] Optionally, the preset charging rate is no higher than 0.2C.

[0058] Preferably, in the embodiment of the present invention, the preset charging rate is any value between 0.05C and 0.1C.

[0059] The second recording module 30 is used to charge the target power battery pack with a preset charging rate again after the target power battery pack continuously runs the preset test cycle under the preset working conditions, and record the second terminal voltage data of the target power battery pack after it is fully charged. The second terminal voltage data includes the charging terminal voltage value corresponding to each string of battery cells of the target power battery pack after running the preset test cycle. Preferably, the preset test cycle is one month.

[0060] The determination module 40 is used to determine the passive balancing capability of the battery management system to be tested based on the first terminal voltage data and the second terminal voltage data.

[0061] The purpose of the present invention is to provide a test system for passive balancing capability. By taking the charging terminal voltage value of the power battery pack before and after the test as the acceptance index, the test result is made more accurate, and the quantitative result of the passive balancing capability of the battery management system is clearer, thereby alleviating the technical problem in the prior art that the balancing capability is difficult to quantify.

[0062] Optionally, Figure 4 is a schematic diagram of a determination module provided according to an embodiment of the present invention. Figure 4 As shown, the determination module 40 further includes: a first determination unit 41 , a second determination unit 42 and a third determination unit 43 .

[0063] Specifically, the first determining unit 41 is used to determine, based on the first terminal voltage data, a maximum state of charge difference of the target power battery pack before running a preset test cycle as a first state of charge difference.

[0064] Specifically, the highest voltage value in the first terminal voltage data is determined to be the first voltage value, and the lowest voltage value in the first terminal voltage data is determined to be the second voltage value; based on a preset correspondence table, the first voltage value is converted into a first state of charge value, and the second voltage value is converted into a second state of charge value; the preset correspondence table is a correspondence table between the state of charge value and the voltage value of each string of battery cells in the target power battery pack; the difference between the first state of charge value and the second state of charge value is determined as the first state of charge difference.

[0065] The second determining unit 42 is configured to determine, based on the second terminal voltage data, a maximum state of charge difference of the target power battery pack after running a preset test cycle as a second state of charge difference.

[0066] Specifically, the highest voltage value in the second terminal voltage data is determined to be the third voltage value, and the lowest voltage value in the second terminal voltage data is determined to be the fourth voltage value; based on a preset correspondence table, the third voltage value is converted into a third state of charge value, and the fourth voltage value is converted into a fourth state of charge value; the difference between the third state of charge value and the fourth state of charge value is determined as the second state of charge difference.

[0067] The third determining unit 43 is used to determine the difference between the first state of charge difference and the second state of charge difference as the passive balancing capability of the battery management system to be tested.

[0068] Optionally, the determination module 40 is further used to: determine the difference between the highest voltage value and the lowest voltage value in the first terminal voltage data to obtain a first voltage difference; determine the difference between the highest voltage value and the lowest voltage value in the second terminal voltage data to obtain a second voltage difference; and finally, subtract the first voltage difference from the second voltage difference to obtain a target voltage difference. The target voltage difference is used as an acceptance index for the passive balancing capability of the battery management system to be tested, or the target voltage difference is converted into a target SOC difference according to the corresponding relationship between the voltage difference and the SOC difference, and the target SOC difference is used as the passive balancing capability of the battery management system to be tested.

[0069] An embodiment of the present invention further provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method in the first embodiment when executing the computer program.

[0070] The embodiment of the present invention further provides a computer-readable medium having a non-volatile program code executable by a processor, wherein the program code enables the processor to execute the method in the above-mentioned embodiment 1.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A passive balancing capability test method, applied to a battery management system to be tested, It is characterized in that include: Discharging the first battery cell so that a difference between a state of charge of the first battery cell and a state of charge of the second battery cell is greater than a preset threshold; The first battery cell is a string of battery cells in a target power battery pack, the second battery cell is a string of battery cells with the lowest state of charge value among the battery cells in the target power battery pack except the first battery cell, and the target power battery pack is a battery pack controlled by the battery management system to be tested; Performing constant current charging on the target power battery pack at a preset charging rate, and recording first terminal voltage data of the target power battery pack after the battery is fully charged; After the target power battery pack continuously runs a preset test cycle under the preset working condition, the target power battery pack is again charged with a constant current at the preset charging rate, and the second terminal voltage data of the target power battery pack is recorded after the target power battery pack is fully charged; Determining the passive balancing capability of the battery management system to be tested based on the first terminal voltage data and the second terminal voltage data; Based on the first terminal voltage data and the second terminal voltage data, the passive balancing capability of the battery management system to be tested is determined, including: based on the first terminal voltage data, determining that the maximum state of charge difference of the target power battery group before running a preset test cycle is a first state of charge difference; based on the second terminal voltage data, determining that the maximum state of charge difference of the target power battery group after running a preset test cycle is a second state of charge difference; and determining the difference between the first state of charge difference and the second state of charge difference as the passive balancing capability of the battery management system to be tested.

2. The method according to claim 1, It is characterized in that Before discharging the first battery cell, the method further includes: The sum of the balancing start threshold of the battery management system to be tested and the rated balancing capacity of the battery management system to be tested is determined as the preset threshold.

3. The method according to claim 1, It is characterized in that The first terminal voltage data includes a charging terminal voltage value corresponding to each string of battery cells of the target power battery pack before running a preset test cycle; Determining, based on the first terminal voltage data, a maximum state of charge difference of the target power battery pack before running a preset test cycle as a first state of charge difference includes: Determine the highest voltage value in the first terminal voltage data as a first voltage value, and determine the lowest voltage value in the first terminal voltage data as a second voltage value; Based on a preset correspondence table, the first voltage value is converted into a first state of charge value, and the second voltage value is converted into a second state of charge value; the preset correspondence table is a correspondence table between the state of charge value and the voltage value of each string of battery cells in the target power battery pack; A difference between the first state of charge value and the second state of charge value is determined as the first state of charge difference.

4. The method according to claim 1, It is characterized in that The second terminal voltage data includes a charging terminal voltage value corresponding to each string of battery cells of the target power battery pack after running a preset test cycle; Determining, based on the second terminal voltage data, that the maximum state of charge difference of the target power battery pack after running a preset test cycle is a second state of charge difference includes: Determine the highest voltage value in the second terminal voltage data as a third voltage value, and determine the lowest voltage value in the second terminal voltage data as a fourth voltage value; Based on a preset correspondence table, the third voltage value is converted into a third state of charge value, and the fourth voltage value is converted into a fourth state of charge value; the preset correspondence table is a correspondence table between the state of charge value and the voltage value of each string of battery cells in the target power battery pack; A difference between the third state of charge value and the fourth state of charge value is determined as the second state of charge difference.

5. The method according to claim 1, It is characterized in that The preset charging rate is no higher than 0.2C.

6. The method according to claim 5, It is characterized in that The preset charging rate is any value between 0.05C and 0.1C.

7. A passive balancing capability test system, applied to the battery management system to be tested, It is characterized in that include: A discharge module, a first recording module, a second recording module and a determination module; wherein, The discharge module is used to discharge the first battery cell so that the difference between the state of charge of the first battery cell and the state of charge of the second battery cell is greater than a preset threshold value; the first battery cell is a string of battery cells in a target power battery pack, the second battery cell is a string of battery cells with the lowest state of charge value among the battery cells in the target power battery pack except the first battery cell, and the target power battery pack is a battery pack controlled by the battery management system to be tested; The first recording module is used to perform constant current charging on the target power battery pack at a preset charging rate, and record first terminal voltage data of the target power battery pack after it is fully charged; The second recording module is used to perform constant current charging on the target power battery pack again at the preset charging rate after the target power battery pack continuously runs a preset test cycle under preset working conditions, and record the second terminal voltage data of the target power battery pack after it is fully charged; The determination module is used to determine the passive balancing capability of the battery management system to be tested based on the first terminal voltage data and the second terminal voltage data; The determination module includes: a first determination unit, a second determination unit and a third determination unit; The first determining unit is used to determine, based on the first terminal voltage data, that the maximum state of charge difference of the target power battery pack before running a preset test cycle is a first state of charge difference; The second determination unit is used to determine, based on the second terminal voltage data, that the maximum state of charge difference of the target power battery pack after running a preset test cycle is a second state of charge difference; The third determining unit is used to determine the difference between the first state of charge difference and the second state of charge difference as the passive balancing capability of the battery management system to be tested.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, It is characterized in that When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A computer readable medium having a non-volatile program code executable by a processor, It is characterized in that The program code enables the processor to execute the method according to any one of claims 1 to 6.

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