A method, device and equipment for testing an electric core

Abstract

The present invention provides a method, device and equipment for testing an electric core, relating to the technical field of batteries. The method for testing the electric core includes: performing multiple rounds of cyclic tests on the electric core at a target ambient temperature, wherein the number of cycles of each round of cyclic test is different, and each round of cyclic test includes multiple tests. Each test includes the following steps: performing overcharge tests on the electric core according to the overcharge durations respectively corresponding to a plurality of preset overcharge voltage limits; and performing a discharge test on the electric core after performing the overcharge test on the electric core. The solution of the present invention can achieve cyclic overcharge tests of the electric core.

Description

Technical Field

[0001] The present invention belongs to the technical field of batteries, and in particular, relates to a method, device, and equipment for testing an electric core. Background Art

[0002] To achieve a long driving range, high-energy lithium-ion batteries have become a key development direction in the fields of electric vehicles and large-scale energy storage devices. However, the safety issue of lithium-ion batteries has always been a major concern for relevant R & D personnel. In particular, the risk of thermal runaway of high-capacity power batteries under abusive conditions will increase significantly, which also greatly limits the widespread application of lithium-ion batteries.

[0003] However, in the prior art, there is a lack of cyclic overcharge testing for battery cells, i.e., electric cores, and it is impossible to judge the safety risks within the full life cycle range of the electric core from the beginning of life (BOL) to the end of life (EOL), let alone guide the safety verification of the electric core during the R & D process. Summary of the Invention

[0004] The purpose of the embodiments of the present invention is to provide a method, device, and equipment for testing an electric core, so as to solve the problem of the lack of cyclic overcharge testing for electric cores in the prior art.

[0005] To achieve the above purpose, the embodiments of the present invention provide a method for testing an electric core, including:

[0006] Performing multiple rounds of cyclic tests on the electric core at a target ambient temperature, where the number of cycles in each round of cyclic test is different, and each round of cyclic test includes multiple tests, and each test includes the following steps:

[0007] Performing overcharge tests on the electric core according to the overcharge durations respectively corresponding to a plurality of preset overcharge voltage limits;

[0008] After performing the overcharge test on the electric core, performing a discharge test on the electric core.

[0009] Optionally, the performing overcharge tests on the electric core according to the overcharge durations respectively corresponding to a plurality of preset overcharge voltage limits includes:

[0010] At the target ambient temperature, charging the electric core to the available cut-off upper limit voltage to make the electric core reach a fully charged state;

[0011] When the electric core reaches the fully charged state, charging the electric core to an overcharge voltage with a preset current, where the overcharge voltage is determined according to the available cut-off upper limit voltage of the electric core at the target ambient temperature and the overcharge voltage limit;

[0012] After the battery cell is charged to the overcharge voltage, within the overcharge duration, the overcharge voltage is used to overcharge the battery cell.

[0013] Optionally, when the battery cell reaches the fully charged state, before charging the battery cell to the overcharge voltage using a preset current, the method further includes:

[0014] When the battery cell reaches the fully charged state, according to the difference between the surface temperature of the battery cell and the target ambient temperature and the open-circuit voltage change value of the battery cell, the static duration of the battery cell is determined.

[0015] Optionally, after performing the overcharge test on the battery cell, performing a discharge test on the battery cell includes:

[0016] Using a preset current, discharging the battery cell to a preset state of charge.

[0017] Optionally, the method further includes:

[0018] After each test, using a preset current to charge the battery cell to the available cut-off upper limit voltage so that the battery cell reaches the fully charged state, and then performing the next test on the battery cell.

[0019] Optionally, the overcharge voltage limit includes a first overcharge voltage limit and a second overcharge voltage limit, the first overcharge voltage limit corresponds to a first overcharge duration, and the second overcharge voltage limit corresponds to a second overcharge duration;

[0020] Wherein, if the first overcharge voltage limit is less than the second overcharge voltage limit, the first overcharge duration is greater than the second overcharge duration.

[0021] Optionally, the method further includes:

[0022] Obtaining the information on the lithium plating situation corresponding to each cycle number of tests performed on the battery cell;

[0023] According to the lithium plating situation information, obtaining the relationship between the cycle number and the battery cell safety to obtain the test result.

[0024] Optionally, before performing multiple cycle tests on the battery cell at the target ambient temperature, the method further includes:

[0025] Obtaining the first physical parameter of the battery cell;

[0026] After performing multiple cycle tests on the battery cell at the target ambient temperature, the method further includes:

[0027] Obtaining the second physical parameter of the battery cell;

[0028] Obtain the physical change result of the battery cell after the cyclic test according to the first physical parameter and the second physical parameter;

[0029] Wherein, the first physical parameter and the second physical parameter both include at least one of the following:

[0030] Capacity, open circuit voltage, internal resistance, and mass.

[0031] To achieve the above object, an embodiment of the present invention further provides a battery cell testing device, including:

[0032] A testing module, configured to perform multiple rounds of cyclic tests on the battery cell at a target ambient temperature, wherein the number of cycles of each round of cyclic test is different, and each round of cyclic test includes multiple tests, and each test includes the following steps:

[0033] Perform overcharge test on the battery cell according to the overcharge durations respectively corresponding to a plurality of preset overcharge voltage limits;

[0034] After performing the overcharge test on the battery cell, perform a discharge test on the battery cell.

[0035] To achieve the above object, an embodiment of the present invention further provides a battery cell testing device, including: a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein when the processor executes the computer program, the battery cell testing method as described above is implemented.

[0036] The above technical solution of the present invention has at least the following beneficial effects:

[0037] In the above solution, by performing multiple rounds of cyclic tests on the battery cell at a target ambient temperature, wherein the number of cycles of each round of cyclic test is different, and each round of cyclic test includes multiple tests, and each test includes the following steps: perform an overcharge test on the battery cell according to the overcharge durations respectively corresponding to a plurality of preset overcharge voltage limits, and after performing the overcharge test on the battery cell, perform a discharge test on the battery cell, thereby realizing the cyclic overcharge test of the battery cell. Description of the Drawings

[0038] Figure 1 It is a step diagram of the battery cell testing method according to an embodiment of the present invention;

[0039] Figure 2 It is an application flow chart of the battery cell testing method according to an embodiment of the present invention;

[0040] Figure 3 It is a schematic diagram of the battery cell testing device according to an embodiment of the present invention. Detailed Embodiments

[0041] To make the technical problems, technical solutions, and advantages to be solved by the present invention clearer, the following will be described in detail with reference to the accompanying drawings and specific embodiments. In the following description, providing specific details such as specific configurations and components is only to help comprehensively understand the embodiments of the present invention. Therefore, those skilled in the art should clearly understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present invention. Additionally, descriptions of known functions and structures are omitted for clarity and conciseness.

[0042] In various embodiments of the present invention, it should be understood that the magnitudes of the serial numbers of the following processes do not mean the order of execution. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

[0043] Embodiments of the present invention address the problem of the lack of cyclic overcharge testing for battery cells in the prior art, and provide a battery cell testing method, device, and equipment.

[0044] Embodiments of the present invention provide a battery cell testing method. Please refer to Figure 1 , and the battery cell testing method includes:

[0045] Step 101, at a target ambient temperature, perform multiple rounds of cyclic testing on the battery cell. Among them, the number of cycles in each round of cyclic testing is different. Each round of cyclic testing includes multiple tests, and each test includes the following steps:

[0046] Perform overcharge testing on the battery cell according to the overcharge durations corresponding to multiple preset overcharge voltage limits.

[0047] After performing the overcharge testing on the battery cell, perform discharge testing on the battery cell.

[0048] In this step, in order to cover the damage degree of the battery cell under overcharge within the entire life cycle range, the number of overcharge tests and discharge tests in each test can be increased. For example, each test can perform a target number of overcharge tests and a target number of discharge tests. The target number is determined based on empirical values or measured values, generally 50 times. Start the next charge test and discharge test after completing one overcharge test and one discharge test.

[0049] It should be noted that embodiments of the present invention preset multiple overcharge voltage limits, and each overcharge voltage limit corresponds to an overcharge duration. According to the overcharge voltage limit and the overcharge duration, overcharge testing is performed on the battery cell. For example, taking a ternary battery cell at an ambient temperature of 25°C as an example, Table 1 shows the corresponding table of the process voltage limit and overcharge duration of this ternary battery cell.

[0050] The overcharge test may include multiple overcharge electronic tests. Here, taking the overcharge test including four overcharge electronic tests as an example as shown in Table 1, for each overcharge electronic test, the overcharge voltage is set according to the overcharge voltage limit in Table 1. Since the available cut-off upper limit voltage of the ternary battery cell at 25°C ambient temperature is 4.2V, the overcharge voltage is equal to the sum of 4.2V and the overcharge voltage limit, and the test is carried out based on the overcharge duration. After testing according to the overcharge voltage limit and overcharge duration corresponding to No. 1 in Table 1, continue to test according to the overcharge voltage limit and overcharge duration corresponding to No. 2 in Table 1, then test according to the overcharge voltage limit and overcharge duration corresponding to No. 3 in Table 1, and finally test according to the overcharge voltage limit and overcharge duration corresponding to No. 4 in Table 1.

[0051] Serial number Overcharge voltage limit (V) Overcharge duration (s) 1 0.05 50 2 0.1 30 3 0.2 20 4 0.3 10

[0052] Table 1

[0053] In the above embodiments of the present invention, by performing multiple rounds of cycle tests on the battery cell at the target ambient temperature, where the number of cycles in each round of cycle test is different, and each round of cycle test includes multiple tests, and each test includes the following steps: performing an overcharge test on the battery cell according to the overcharge durations respectively corresponding to a plurality of preset overcharge voltage limits, and after performing the overcharge test on the battery cell, performing a discharge test on the battery cell, so as to realize the cycle overcharge test of the battery cell.

[0054] It should be noted that battery cell tests at different ambient temperatures can be carried out to cover the scenarios of battery cell overcharge damage of the whole vehicle at different ambient temperatures.

[0055] In a specific embodiment of the present invention, the performing an overcharge test on the battery cell according to the overcharge durations respectively corresponding to a plurality of preset overcharge voltage limits includes:

[0056] At the target ambient temperature, charging the battery cell to the available cut-off upper limit voltage to make the battery cell reach a fully charged state;

[0057] When the battery cell reaches the fully charged state, using a preset current to charge the battery cell to the overcharge voltage, and the overcharge voltage is determined according to the available cut-off upper limit voltage of the battery cell at the target ambient temperature and the overcharge voltage limit;

[0058] After the battery cell is charged to the overcharge voltage, during the overcharge duration, using the overcharge voltage to perform overcharge on the battery cell.

[0059] First, at the target ambient temperature, charge the battery cell to the fully charged state, that is, SOC = 100%.

[0060] Then, since the overcharge test may include multiple tests, first, the battery cell is charged to a first overcharge voltage using a preset current. The first overcharge voltage is determined based on the available cut-off upper limit voltage of the battery cell and the first overcharge voltage limit, and the battery cell is charged at the first overcharge voltage for a first overcharge duration.

[0061] After the first overcharge duration is reached, the battery cell is then charged to a second overcharge voltage using a preset current. The second overcharge voltage is determined based on the available cut-off upper limit voltage of the battery cell and the second overcharge voltage limit, and the battery cell is charged at the second overcharge voltage for a second overcharge duration.

[0062] It should be noted that the first overcharge voltage limit is less than the second overcharge voltage limit; the first overcharge duration is greater than the second overcharge duration.

[0063] In an embodiment of the present invention, before charging the battery cell to the overcharge voltage using a preset current when the battery cell reaches the fully charged state, the method further includes:

[0064] When the battery cell reaches the fully charged state, the rest duration of the battery cell is determined according to the difference between the surface temperature of the battery cell and the target ambient temperature and the open-circuit voltage change value of the battery cell.

[0065] That is to say, it is necessary to determine the rest duration of the battery cell according to the difference between the surface temperature of the battery cell and the target ambient temperature and the open-circuit voltage change value of the battery cell to ensure that the battery cell reaches the thermal equilibrium state.

[0066] The difference between the surface temperature of the battery cell and the target ambient temperature is required not to exceed 2°C, and the open-circuit voltage change value of the battery cell every 15 minutes is required not to exceed 15 mV. Generally, the rest duration of the battery cell is 2 hours. If the above requirements are not met, the rest duration of the battery cell is increased on the basis of 2 hours.

[0067] In an embodiment of the present invention, after the overcharge test is performed on the battery cell, the discharge test on the battery cell includes:

[0068] The battery cell is discharged to a preset state of charge using a preset current.

[0069] It should be noted that after the battery cell completes the overcharge test, the battery cell is discharged to a preset state of charge using a preset current, and the preset state of charge is less than 100%, for example, SOC = 90%.

[0070] In an embodiment of the present invention, the above method further includes:

[0071] After each test, the preset current is used to charge the battery cell to the available cut-off upper limit voltage so that the battery cell reaches the fully charged state, and then the next test is performed on the battery cell.

[0072] It should be noted that after each test, the preset current is used to recharge the battery cell to the fully charged state to prepare for the next test.

[0073] It should also be noted that the above preset current is a very small current, such as 1 / 10 A.

[0074] In a specific embodiment of the present invention, the overcharge voltage limit includes a first overcharge voltage limit and a second overcharge voltage limit. The first overcharge voltage limit corresponds to a first overcharge duration, and the second overcharge voltage limit corresponds to a second overcharge duration;

[0075] Wherein, if the first overcharge voltage limit is less than the second overcharge voltage limit, then the first overcharge duration is greater than the second overcharge duration.

[0076] That is to say, different overcharge voltage limits correspond to different overcharge durations, and the larger the overcharge voltage limit, the shorter the corresponding overcharge duration.

[0077] In an embodiment of the present invention, the above method further includes:

[0078] Obtain the information on the lithium plating situation corresponding to each cycle number of tests of the battery cell;

[0079] According to the lithium plating situation information, obtain the relationship between the cycle number and the safety of the battery cell to obtain the test result.

[0080] It should be noted that after each round of cycle test of the battery cell is completed, the battery cell is disassembled to obtain the lithium plating situation information, and the interface and morphology of the battery cell are analyzed, so as to know the relationship between the cycle number and the safety of the battery cell, obtain the test results of the entire life cycle, and systematically evaluate the safety impact of overcharge cycling of the battery cell throughout its life cycle.

[0081] In an embodiment of the present invention, before performing multiple rounds of cycle tests on the battery cell at the target ambient temperature, the method further includes:

[0082] Obtain the first physical parameter of the battery cell;

[0083] After performing multiple rounds of cycle tests on the battery cell at the target ambient temperature, the method further includes:

[0084] Obtain the second physical parameter of the battery cell;

[0085] According to the first physical parameter and the second physical parameter, obtain the physical change result of the battery cell after the cycle test;

[0086] Wherein, both the first physical parameter and the second physical parameter include at least one of the following:

[0087] Capacity, open circuit voltage, internal resistance, and mass.

[0088] It should be noted that the physical parameters of the battery cell before and after the cycle test are analyzed to compare the changes in the battery cell before and after the cycle test.

[0089] It should also be noted that the above method further includes:

[0090] Obtaining overcharge data during vehicle use;

[0091] Based on the overcharge data and the above test results, determining whether there is a safety risk in the vehicle.

[0092] That is to say, through the above multi-round cycle tests, the safety state of the battery cell after overcharge can be identified in advance, and by analyzing the lithium plating situation information obtained from subsequent disassembly, the internal characteristics of the battery cell can be studied to obtain test results, providing effective support for the safety assessment of the battery cell in the actual vehicle use scenario.

[0093] Please refer to Figure 2 , and the following describes the specific implementation process above in combination with the specific implementation flow:

[0094] Step 201, perform a physical parameter test on the battery cell to obtain the first physical parameter of the battery cell.

[0095] Step 202, charge the battery cell to a fully charged state at the target ambient temperature.

[0096] Step 203, let the battery cell stand still to adapt to the environment to reach a thermal equilibrium state.

[0097] Step 204, perform an overcharge test on the battery cell: using a preset current, charge the battery cell to an overcharge voltage, and maintain the overcharge voltage for the overcharge duration to perform the overcharge test; this overcharge test includes multiple overcharge sub-tests, and the next overcharge sub-test is executed after one overcharge sub-test ends.

[0098] Step 205, perform a discharge test on the battery cell: using a preset current, discharge the battery cell to a preset state of charge.

[0099] Step 206, recharge the battery cell to a fully charged state using a preset current.

[0100] Step 207, repeat steps 204 to 206 a preset number of times to complete one round of cycle test.

[0101] Step 208: Repeat the above steps 201 to 207 at different ambient temperatures to cover the scenarios of overcharge damage of the battery cells of the whole vehicle at different ambient temperatures.

[0102] In summary, the battery cell testing method according to the embodiment of the present invention can cover the overcharge scenarios in the whole life cycle of the battery cell, so as to simulate the safety risks when the battery management system strategy fails or under overcurrent impact and the battery cell is at the available cut-off voltage, and can evaluate the situation of overvoltage use of the battery cell during the whole life cycle of the battery cell. This battery cell testing method can shorten the testing cycle, is suitable for the testing and evaluation in the research and development verification stage of the battery cell, and covers the whole life cycle scenarios.

[0103] An embodiment of the present invention further provides a battery cell testing device. Please refer to Figure 3 , the battery cell testing device includes:

[0104] A testing module 301, configured to perform multiple rounds of cyclic testing on the battery cell at a target ambient temperature, wherein the number of cycles of each round of cyclic testing is different, and each round of cyclic testing includes multiple tests, and each test includes the following steps:

[0105] Perform overcharge testing on the battery cell according to the overcharge durations respectively corresponding to a plurality of preset overcharge voltage limits;

[0106] After performing the overcharge testing on the battery cell, perform discharge testing on the battery cell.

[0107] In the above embodiment of the present invention,

[0108] Optionally, the testing module 301 is specifically configured to:

[0109] At the target ambient temperature, charge the battery cell to the available cut-off upper limit voltage to make the battery cell reach the full charge state;

[0110] When the battery cell reaches the full charge state, use a preset current to charge the battery cell to the overcharge voltage, and the overcharge voltage is determined according to the available cut-off upper limit voltage of the battery cell at the target ambient temperature and the overcharge voltage limit;

[0111] After the battery cell is charged to the overcharge voltage, perform overcharge on the battery cell with the overcharge voltage within the overcharge duration.

[0112] Optionally, the above device further includes:

[0113] A determination module, configured to determine the rest duration of the battery cell according to the difference between the surface temperature of the battery cell and the target ambient temperature and the change value of the open-circuit voltage of the battery cell when the battery cell reaches the full charge state.

[0114] Optionally, the test module 301 is specifically configured to:

[0115] Discharge the battery cell to a preset state of charge using a preset current.

[0116] Optionally, the above device further includes:

[0117] A charging module, configured to, after each test, charge the battery cell to an available cut-off upper limit voltage using a preset current, so that the battery cell reaches a full charge state, and then perform the next test on the battery cell.

[0118] Optionally, the overcharge voltage limit includes a first overcharge voltage limit and a second overcharge voltage limit, the first overcharge voltage limit corresponding to a first overcharge duration, and the second overcharge voltage limit corresponding to a second overcharge duration;

[0119] Wherein, if the first overcharge voltage limit is less than the second overcharge voltage limit, then the first overcharge duration is greater than the second overcharge duration.

[0120] Optionally, the above device further includes:

[0121] A first acquisition module, configured to acquire the information on the lithium deposition situation corresponding to each cycle number of tests performed on the battery cell;

[0122] A second acquisition module, configured to obtain the relationship between the cycle number and the battery cell safety according to the lithium deposition situation information, and obtain a test result.

[0123] Optionally, the above device further includes:

[0124] A third acquisition module, configured to acquire a first physical parameter of the battery cell;

[0125] A fourth acquisition module, configured to acquire a second physical parameter of the battery cell;

[0126] A fifth acquisition module, configured to obtain a physical change result of the battery cell after the cycle test according to the first physical parameter and the second physical parameter;

[0127] Wherein, the first physical parameter and the second physical parameter both include at least one of the following:

[0128] Capacity, open circuit voltage, internal resistance, and mass.

[0129] It should be noted that the above device provided by the embodiments of the present invention can implement all the method steps implemented by the embodiments of the above battery cell test method, and can achieve the same technical effects. The same parts and beneficial effects as those in the method embodiments will not be specifically described in this embodiment.

[0130] An embodiment of the present invention further provides a battery cell testing device, including: a memory, a processor, and a computer program stored on the memory and executable on the processor, where when the processor executes the computer program, the above-mentioned battery cell testing method is implemented.

[0131] It should be noted that the above-mentioned battery cell testing device provided by the embodiment of the present invention can implement all the method steps implemented by the above-mentioned battery cell testing method embodiment, and can achieve the same technical effects. The same parts and beneficial effects as those in the method embodiment will not be specifically described in this embodiment.

[0132] The above is the preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for testing an electric cell, characterized in that, it includes: Performing multiple rounds of cyclic tests on the electric cell at a target ambient temperature, wherein the number of cycles of each round of cyclic test is different, and each round of cyclic test includes multiple tests, and each test includes the following steps: Performing overcharge tests on the electric cell according to the overcharge durations respectively corresponding to multiple preset overcharge voltage limits; After performing the overcharge test on the electric cell, performing a discharge test on the electric cell; performing the overcharge test on the electric cell according to the overcharge durations respectively corresponding to multiple preset overcharge voltage limits includes: At the target ambient temperature, charging the electric cell to the available cut-off upper limit voltage to make the electric cell reach a fully charged state; When the electric cell reaches the fully charged state, using a preset current to charge the electric cell to the overcharge voltage, and the overcharge voltage is determined according to the available cut-off upper limit voltage of the electric cell at the target ambient temperature and the overcharge voltage limit; After the electric cell is charged to the overcharge voltage, performing overcharge on the electric cell with the overcharge voltage within the overcharge duration; The overcharge voltage limits include a first overcharge voltage limit and a second overcharge voltage limit, the first overcharge voltage limit corresponds to a first overcharge duration, and the second overcharge voltage limit corresponds to a second overcharge duration; Wherein, if the first overcharge voltage limit is less than the second overcharge voltage limit, then the first overcharge duration is greater than the second overcharge duration.

2. The method for testing an electric cell according to claim 1, characterized in that, Before using a preset current to charge the electric cell to the overcharge voltage when the electric cell reaches the fully charged state, the method further includes: When the electric cell reaches the fully charged state, determining the rest duration of the electric cell according to the difference between the surface temperature of the electric cell and the target ambient temperature and the open-circuit voltage change value of the electric cell.

3. The method for testing an electric cell according to claim 1, characterized in that, Performing a discharge test on the electric cell after performing the overcharge test on the electric cell includes: Using a preset current to discharge the electric cell to a preset state of charge.

4. The method for testing an electric cell according to claim 1, characterized in that, it further includes: After each test, using a preset current to charge the electric cell to the available cut-off upper limit voltage to make the electric cell reach a fully charged state, and then performing the next test on the electric cell.

5. The method for testing an electric cell according to claim 1, characterized in that, the method further includes: Obtaining the information on the lithium deposition situation corresponding to each test of the electric cell; According to the information on the lithium deposition situation, obtaining the relationship between the number of cycles and the safety of the electric cell to obtain the test result.

6. The method for testing an electric cell according to claim 1, characterized in that, Before performing multiple rounds of cyclic tests on the electric cell at the target ambient temperature, the method further includes: Obtaining the first physical parameter of the electric cell; After performing multiple rounds of cyclic tests on the electric cell at the target ambient temperature, the method further includes: Obtaining the second physical parameter of the electric cell; Obtain the physical change result of the battery cell after the cycle test according to the first physical parameter and the second physical parameter; Wherein, the first physical parameter and the second physical parameter both include at least one of the following: Capacity, open circuit voltage, internal resistance, and mass.

7. A battery cell testing device, Characterized in that, It includes: A testing module, configured to perform multiple rounds of cycle tests on the battery cell at a target ambient temperature, wherein the number of cycles of each round of cycle test is different, and each round of cycle test includes multiple tests, and each test includes the following steps: Perform overcharge tests on the battery cell according to the overcharge durations respectively corresponding to a plurality of preset overcharge voltage limits; After performing the overcharge test on the battery cell, perform a discharge test on the battery cell; Wherein, the testing module is specifically configured to: Charge the battery cell to the available cut-off upper limit voltage at the target ambient temperature to make the battery cell reach a fully charged state; When the battery cell reaches the fully charged state, use a preset current to charge the battery cell to the overcharge voltage, and the overcharge voltage is determined according to the available cut-off upper limit voltage of the battery cell at the target ambient temperature and the overcharge voltage limit; After the battery cell is charged to the overcharge voltage, perform overcharge on the battery cell with the overcharge voltage within the overcharge duration; The overcharge voltage limit includes a first overcharge voltage limit and a second overcharge voltage limit, the first overcharge voltage limit corresponds to a first overcharge duration, and the second overcharge voltage limit corresponds to a second overcharge duration; Wherein, if the first overcharge voltage limit is less than the second overcharge voltage limit, then the first overcharge duration is greater than the second overcharge duration.

8. A battery cell testing equipment, Characterized in that, It includes: A memory, a processor, and a computer program stored on the memory and executable on the processor, and when the processor executes the computer program, it implements the battery cell testing method according to any one of claims 1 to 6.

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