A capacity attenuation coefficient determination method, device and storage medium

Abstract

The application discloses a capacity attenuation coefficient determination method, equipment and storage medium, the capacity attenuation coefficient determination method comprises the following steps: controlling the temperature difference of the battery module of the test group, adopting the same cycle test condition to the test group battery module, the control group battery module is tested except the temperature difference of the battery cell; the capacity attenuation of the test group battery module is obtained, and the first capacity attenuation is recorded; the capacity attenuation of the control group battery module is obtained, and the second capacity attenuation is recorded; the capacity attenuation coefficient is determined according to the first capacity attenuation and the second capacity attenuation, and the capacity attenuation coefficient is used to determine the life of the target battery module. In the method, the capacity attenuation coefficient is associated with the temperature difference between the battery module and the battery cell, and then when the life of the battery module is determined based on the capacity attenuation coefficient, the accuracy of the life prediction of the battery module can be improved.

Description

Technical Field

[0001] The present invention relates to battery technology, and more particularly to a method, device and storage medium for determining capacity decay coefficient. Background Technology

[0002] In recent years, lithium-ion batteries have been widely used in new energy vehicles and grid energy storage. However, lithium-ion batteries experience irreversible performance degradation during use. A lithium-ion battery is a complex electrochemical system that undergoes side reactions during operation, such as solid electrolyte interphase (SEI) growth, lithium plating, and electrolyte oxidation. These side reactions lead to performance degradation, macroscopically manifested as reduced capacity and increased internal resistance, thus shortening the battery's lifespan.

[0003] Accurately predicting the lifespan of lithium-ion batteries under different usage conditions can not only ensure the safe and reliable operation of the system, but also maximize the utilization of the remaining value of lithium-ion batteries.

[0004] Currently, the lifespan prediction of battery modules is usually based on the lifespan of the battery cells multiplied by a certain coefficient. However, this coefficient is too simple and lacks a certain reference standard, which can easily lead to different deviations in the prediction of battery module lifespan under different operating conditions. Summary of the Invention

[0005] This invention provides a method, device, and storage medium for determining the capacity decay coefficient, in order to improve the accuracy of battery module life prediction.

[0006] In a first aspect, embodiments of the present invention provide a method for determining the capacity attenuation coefficient, comprising:

[0007] Control the cell temperature difference of the test group battery module, and except for the cell temperature difference, use the same cyclic test conditions to perform cyclic tests on the test group battery module and the control group battery module;

[0008] The capacity decay of the test group battery module is obtained and recorded as the first capacity decay; the capacity decay of the control group battery module is obtained and recorded as the second capacity decay.

[0009] The capacity attenuation coefficient is determined based on the first capacity attenuation and the second capacity attenuation.

[0010] The capacity decay coefficient is used to determine the lifespan of the target battery module.

[0011] Optionally, it also includes: controlling the cell temperature difference and the maximum cell temperature of the test group battery module, and performing the cyclic test on the test group battery module using the same cyclic test conditions, except for the cell temperature difference and the maximum cell temperature;

[0012] The capacity decay of the test group battery module, where the cell temperature difference and the highest cell temperature are controlled quantities, is denoted as the third capacity decay.

[0013] The capacity attenuation coefficient is determined based on the first capacity attenuation, the second capacity attenuation, and the third capacity attenuation.

[0014] Optionally, it also includes: setting a first test battery module, a second test battery module, and a third test battery module;

[0015] The cell temperature difference between the first test battery module and the third test battery module is set as the first temperature difference, and the cell temperature difference of the second test battery module is set as the second temperature difference.

[0016] The highest cell temperature in the first and second test battery modules is set as the first temperature, and the highest cell temperature in the third test battery module is set as the second temperature.

[0017] In addition to controlling the cell temperature difference of the first test battery module and the third test battery module to be the first temperature difference, and the cell temperature difference of the second test battery module to be the second temperature difference; and controlling the highest cell temperature in the first test battery module and the second test battery module to be the first temperature, and controlling the highest cell temperature in the third test battery module to be the second temperature, the same cyclic test conditions are used to perform cyclic tests on the first test battery module, the second test battery module, and the third test battery module.

[0018] Based on the cyclic test, the capacity decay of the first test battery module, the second test battery module, and the third test battery module is obtained and recorded as the fourth capacity decay.

[0019] The capacity decay coefficient is determined based on the first capacity decay, the second capacity decay, and the fourth capacity decay.

[0020] Optionally, determining the first temperature includes:

[0021] Perform a specified number of charge-discharge cycles on the first test battery module or the second test battery group, and record the maximum temperature of the cells in the first test battery module or the second test battery group as the first temperature.

[0022] Determining the second temperature includes:

[0023] The third test battery module is subjected to a specified number of charge-discharge cycles, and the maximum temperature of the battery cell of the third test battery module is recorded as the second temperature.

[0024] Optionally, when performing different cyclic tests, the first temperature difference and the second temperature difference are controlled to change, while the first temperature and the second temperature remain unchanged.

[0025] Optionally, determining the capacity attenuation coefficient based on the first capacity attenuation, the second capacity attenuation, and the fourth capacity attenuation includes:

[0026] The cell-module attenuation model is determined based on the first capacity attenuation, the second capacity attenuation, and the fourth capacity attenuation, and the capacity attenuation coefficient is determined based on the cell-module attenuation model.

[0027] The cell-module attenuation module is represented by the following formula:

[0028]

[0029] In the above formula, ΔT represents the capacity decay coefficient, ΔT represents the cell temperature difference, and Tmax represents the highest cell temperature.

[0030] Optionally, determining the lifespan of the target battery module based on the capacity degradation coefficient includes:

[0031] Determine the maximum temperature difference between the cells of the target battery module, and determine the capacity decay coefficient that matches the maximum temperature difference.

[0032] Obtain the operating condition parameters of the target battery module, and determine the capacity decay of the target battery module based on the operating condition parameters;

[0033] The lifespan of the target battery module is determined based on the capacity decay coefficient and the capacity decay.

[0034] Optionally, after determining the maximum temperature difference between the cells of the target battery module, the method further includes:

[0035] If the maximum temperature difference exceeds the temperature difference threshold, the target battery module is controlled to cool down.

[0036] Controlling the cooling of the target battery module includes:

[0037] Change one or more of the following: heating power of the heating film, heating time, and adjustment of the coolant temperature and flow rate of the liquid cooling system.

[0038] Secondly, embodiments of the present invention also provide an electronic device, including at least one processor and a memory communicatively connected to the at least one processor;

[0039] The memory stores a computer program that can be executed by the at least one processor, the computer program being executed by the at least one processor to enable the at least one processor to perform the capacity attenuation coefficient determination method described in the embodiments of the present invention.

[0040] Thirdly, embodiments of the present invention also provide a computer-readable storage medium storing computer instructions, which are used to cause a processor to execute the capacity attenuation coefficient determination method described in the embodiments of the present invention.

[0041] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention proposes a method for determining the capacity decay coefficient. In this method, a test group battery module and a control group battery module are set. The test battery module is subjected to cyclic testing under a set cell temperature difference, and the first capacity decay of the cyclic test is recorded. Except for the cell temperature difference, the control group battery module is subjected to cyclic testing under the same test conditions, and the second capacity decay of the cyclic test is recorded. The capacity decay coefficient is determined by the first capacity decay and the second capacity decay. In this method, the capacity decay coefficient is correlated with the temperature difference between the cells in the battery module, thereby improving the accuracy of battery module life prediction when determining the life of the battery module based on the capacity decay coefficient. Attached Figure Description

[0042] Figure 1 This is a flowchart of the capacity attenuation coefficient determination method in the embodiment;

[0043] Figure 2 This is a schematic diagram of the battery module in the embodiment;

[0044] Figure 3 This is a flowchart of the battery module life determination method in the embodiment;

[0045] Figure 4 This is a flowchart of another method for determining the lifespan of a battery module in the embodiment;

[0046] Figure 5 This is a flowchart of another method for determining the capacity attenuation coefficient in the embodiment;

[0047] Figure 6 This is a flowchart of another method for determining the capacity attenuation coefficient in the embodiments;

[0048] Figure 7 This is a schematic diagram of the capacity decay curve in the embodiment;

[0049] Figure 8 This is a schematic diagram of the cell-module attenuation model curve in the embodiment;

[0050] Figure 9This is a schematic diagram of the electronic device structure in the embodiment. Detailed Implementation

[0051] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0052] Example 1

[0053] Figure 1 This is a flowchart of the capacity attenuation coefficient determination method in the embodiment, for reference. Figure 1 Methods for determining the capacity attenuation coefficient include:

[0054] S101. Control the cell temperature difference of the test group battery module. Except for the cell temperature difference, use the same cyclic test conditions to conduct cyclic tests on the test group battery module and the control group battery module.

[0055] For example, in this solution, a test group battery module and a control group battery module are set up, wherein the test group battery module and the control group battery module have the same physical parameters (such as the number of cells, rated charge and discharge current, service life, etc.).

[0056] For example, in this solution, the test group battery module and the control group battery module are subjected to cyclic testing simultaneously under the same cyclic testing conditions. The difference between the test group battery module and the control group battery module during cyclic testing is that, in addition to the predetermined cyclic testing conditions, the cell temperature difference of the test group battery module is actively controlled.

[0057] For example, in this solution, the cyclic test conditions and corresponding steps are not specifically limited. For instance, the cyclic test can be completed by referring to any test process specified in the prior art for cycle life test, charge-discharge test, or SOC test.

[0058] For example, in this solution, the cell temperature difference is kept constant during one cycle test, and the cell temperature difference is changed during different cycles of testing.

[0059] For example, in this solution, there are no specific limitations on the method of controlling the cell temperature difference of the test group battery module. Figure 2 This is a schematic diagram of the battery module in the embodiment, for reference. Figure 2 Active control of cell temperature difference can be achieved in the following ways.

[0060] refer to Figure 2The battery module includes cells T1 to T12. A first end plate 111 and a first end plate 112 are respectively configured at both ends of the battery module. A first heating film 211 is configured at the first end plate 111, and a second heating film 212 is configured at the first end plate 112. A thermocouple (not shown in the figure) is also configured at each of the cells T1 to T12.

[0061] For example, in this solution, the temperature difference between cell T1 and cell T12 is set as the cell temperature difference, and the first heating film 211 is set to heat cell T1 and the second heating film 212 is set to heat cell T12.

[0062] For example, in this solution, the first heating film 211 and the second heating film 212 are respectively connected to a programmable power supply. The programmable power supply adjusts the current output to the first heating film 211 and / or the second heating film 212 to achieve power adjustment of the heating film, thereby controlling the temperature difference between the battery cell T1 and the battery cell T12 to the set battery cell temperature difference.

[0063] S102. Obtain the capacity decay of the test group battery module, denoted as the first capacity decay, and obtain the capacity decay of the control group battery module, denoted as the second capacity decay.

[0064] For example, in this scheme, the cyclic test can be performed in multiple rounds. After each round of cyclic test is completed, the capacity decay of the test group battery module is recorded as the first capacity decay (that is, after multiple rounds of cyclic test, multiple first capacity decays are recorded), and the capacity decay of the control group battery module after a round of cyclic test is recorded as the second capacity decay.

[0065] S103. Determine the capacity attenuation coefficient based on the first capacity attenuation and the second capacity attenuation.

[0066] For example, in this scheme, the capacity attenuation coefficient corresponding to the remaining first capacity attenuations can be determined by using the second capacity attenuation as a benchmark.

[0067] For example, in this embodiment, the capacity degradation coefficient is used to determine the lifespan of the target battery module (e.g., a vehicle battery module in use). Figure 3 This is a flowchart of the battery module life determination method in the embodiment, for reference. Figure 3 Determining the lifespan of the target battery module includes:

[0068] S1. Determine the maximum temperature difference between the cells of the target battery module, and determine the capacity decay coefficient that matches the maximum temperature difference.

[0069] For example, in this solution, the temperature of each cell in the target battery module is obtained during the use of the target battery module, the temperature difference between the cells is determined based on the temperature of the cells, and then the maximum temperature difference between the cells is determined.

[0070] For example, in this solution, once the cell temperature difference (maximum temperature difference) is determined, the corresponding capacity decay coefficient can be determined based on the pre-stored cell temperature difference-capacity decay coefficient MAP.

[0071] S2. Obtain the operating parameters of the target battery module and determine the capacity degradation of the battery module based on the operating parameters.

[0072] For example, in this solution, the operating parameters of the target battery module can be determined according to its configured Battery Management System (BMS), that is, the operating parameters can be one or more of the parameters collected (monitored) by the BMS configuration.

[0073] For example, in this solution, the operating parameters may specifically include one or more of the following: charging and discharging current, depth of charge and discharge, and ambient temperature.

[0074] For example, in this solution, there is no limitation on the method of determining the capacity decay of the target battery module through operating condition parameters. Any capacity decay determination method in the prior art can be used to determine the capacity decay of the target battery module.

[0075] S3. Determine the lifespan of the target battery module based on the capacity decay coefficient and capacity decay.

[0076] For example, in this solution, the lifespan of the target battery module can be determined according to the following formula:

[0077]

[0078] In the above formula, Q module Indicates the lifespan of the target battery module. Q represents the capacity decay coefficient. cell This indicates capacity decay.

[0079] Figure 4 This is a flowchart of another battery module lifespan determination method in the embodiments, see reference. Figure 4 ,exist Figure 3 Based on the scheme shown, as an alternative implementation method, the method for determining the lifespan of the target battery module can also be:

[0080] S1. Determine the maximum temperature difference between the cells of the target battery module, and determine the capacity decay coefficient that matches the maximum temperature difference.

[0081] S2. Obtain the operating parameters of the target battery module and determine the capacity degradation of the target battery module based on the operating parameters.

[0082] S3. Determine the lifespan of the target battery module based on the capacity decay coefficient and capacity decay.

[0083] For example, in this solution, the implementation methods of steps S1 to S3 are the same as... Figure 5 The corresponding content recorded in the scheme shown is the same.

[0084] S4. If the maximum temperature difference exceeds the temperature difference threshold, control the target battery module to cool down.

[0085] For example, if the temperature difference between the cells is too large, it may cause the lifespan of the target battery module to fail to meet the warranty requirements. In this solution, if it is determined that the maximum temperature difference between the cells exceeds the temperature difference threshold, the target battery module is actively controlled to cool down.

[0086] For example, in this scheme, the temperature difference threshold can be an empirical value or determined through calibration tests.

[0087] For example, in this solution, the active cooling control of the target battery module can be achieved by adjusting the coolant temperature and / or flow rate of the liquid cooling system (configured by the target battery module); if the target battery module is equipped with a heating film, the active cooling control can also be achieved by changing the heating power and / or heating time of the heating film.

[0088] This invention proposes a method for determining the capacity decay coefficient. In this method, a test battery module and a control battery module are set up. The test battery module is subjected to cyclic testing under a set cell temperature difference, and the first capacity decay of the cyclic test is recorded. The control battery module is subjected to cyclic testing under the same test conditions (excluding cell temperature difference), and the second capacity decay of the cyclic test is recorded. The capacity decay coefficient is determined by the first and second capacity decays. In this method, the capacity decay coefficient is correlated with the temperature difference between the cells in the battery module, thereby improving the accuracy of battery module lifespan prediction when determining the battery module's lifespan based on the capacity decay coefficient.

[0089] Figure 5 This is a flowchart of another method for determining the capacity attenuation coefficient in the embodiments, see reference. Figure 5 ,exist Figure 1 Based on the scheme shown, the methods for determining the capacity attenuation coefficient include:

[0090] S201. Control the cell temperature difference of the test group battery module. Except for the cell temperature difference, use the same cyclic test conditions to conduct cyclic tests on the test group battery module and the control group battery module.

[0091] S202. Obtain the capacity decay of the test group battery module, denoted as the first capacity decay, and obtain the capacity decay of the control group battery module, denoted as the second capacity decay.

[0092] For example, in this solution, steps S201 and S202 are implemented in the same way as steps S101 and S102.

[0093] S203. Control the cell temperature difference and maximum cell temperature of the battery module in the test group. Except for the cell temperature difference and maximum cell temperature, use the same cyclic test conditions to perform cyclic tests on the battery module in the test group.

[0094] For example, in this solution, there is no specific limitation on the method of controlling the highest cell temperature of the battery module in the test group. For example, the cell can be heated by a heating film, and the highest temperature of the cell can be controlled to a specified temperature by controlling the power of the heating film.

[0095] S204. Obtain the capacity decay of the test group battery module with cell temperature difference and the highest cell temperature as the controlled quantity, and record it as the third capacity decay.

[0096] For example, in this scheme, for ease of description, the test group battery module with cell temperature difference as the controlled quantity alone is referred to as the first battery group, and the test group battery module with cell temperature difference and maximum cell temperature as the controlled quantities simultaneously is referred to as the second battery group.

[0097] Among them, the same number of multiple cycles of testing were performed on the first battery pack and the second battery pack. During different cycles of testing, the highest cell temperature of the second battery pack was kept constant.

[0098] During a single cycle test, the temperature difference between the cells of the first and second battery packs is kept constant and the same. During different cycles of testing, the temperature difference between the cells is controlled to change.

[0099] S205. Determine the capacity decay coefficient based on the first capacity decay, the second capacity decay, and the third capacity decay.

[0100] For example, in this scheme, the second capacity decay is used as a benchmark to determine the capacity decay coefficients corresponding to the remaining first capacity decay and the third capacity decay.

[0101] In this plan, Figure 1 Based on the beneficial effects of the proposed scheme, the highest cell temperature of the test group battery module is also controlled during the cyclic test. Under the same test conditions, the test group battery module with cell temperature difference and highest cell temperature as controlled variables is subjected to cyclic test, and the third capacity decay of the cyclic test is recorded. The capacity decay coefficient is determined by the first capacity decay, the second capacity decay, and the third capacity decay. The capacity decay coefficient is correlated with the temperature difference between cells in the battery module and the cell temperature, which can further improve the accuracy of battery module life prediction.

[0102] Figure 6This is a flowchart of another method for determining the capacity attenuation coefficient in the embodiments, see reference. Figure 6 ,exist Figure 1 Based on the scheme shown, the methods for determining the capacity attenuation coefficient include:

[0103] S301. Control the cell temperature difference of the test group battery module. Except for the cell temperature difference, use the same cyclic test conditions to perform cyclic tests on the test group battery module and the control group battery module.

[0104] S302. Obtain the capacity decay of the test group battery module, denoted as the first capacity decay, and obtain the capacity decay of the control group battery module, denoted as the second capacity decay.

[0105] S303. Set up the first test battery module, the second test battery module, and the third test battery module.

[0106] For example, in this embodiment, the physical parameters (such as the number of cells, rated charge and discharge current, service life, etc.) of the first test battery module and the second test battery module are the same, while the physical parameters of the first test battery module and the third test battery module are different.

[0107] The differences between the third test battery module and the first test battery module include at least the following: the highest temperature that the cells in the third test battery module can reach is higher than the highest temperature that the cells in the first test battery module can reach.

[0108] S304. Control the cell temperature difference of the first test battery module to the first temperature difference, control the cell temperature difference of the second test battery module to the second temperature difference, and control the cell temperature difference of the third test battery module to the first temperature difference.

[0109] S305. Control the highest cell temperature in the first test battery module and the second test battery module to a first temperature, and control the highest cell temperature in the third test battery module to a second temperature.

[0110] S306. Perform cyclic testing on the first test battery module, the second test battery module, and the third test battery module under the same cyclic test conditions.

[0111] In conjunction with steps S302 to S306, in this embodiment, the first test battery module, the second test battery module, and the third test battery module are subjected to cyclic testing. In addition to the cyclic testing conditions, the cell temperature and cell temperature difference of the first test battery module, the second test battery module, and the third test battery module are actively controlled.

[0112] For example, in this embodiment, the cyclic test conditions and corresponding steps are not specifically limited. For instance, the cyclic test can be completed by referring to any test process specified in the prior art for cycle life test, charge-discharge test, or SOC test.

[0113] For example, in this embodiment, during the cyclic test, the highest cell temperature of the first test battery module and the second test battery module is controlled to be the same, but the cell temperature difference is different.

[0114] The highest cell temperature of the first test battery module and the third test battery module are controlled to be different, while the cell temperature difference is the same.

[0115] For example, in this embodiment, during the cyclic test, the cell temperature difference of the first test battery module and the third test battery module is controlled to be the first temperature difference, and the cell temperature difference of the second test battery module is controlled to be the second temperature difference; the highest cell temperature in the first test battery module and the second test battery module is controlled to be the first temperature, and the highest cell temperature in the third test battery module is controlled to be the second temperature, and the other cyclic test conditions are the same.

[0116] For example, in this solution, the method of controlling the cell temperature difference of the test group battery module is not specifically limited; refer to... Figure 2 Active control of cell temperature and cell temperature difference can be achieved through the following methods.

[0117] refer to Figure 2 Battery module (settings) Figure 2 The battery module shown is the first test battery module. Taking the first test battery module as an example, the active control of cell temperature and cell temperature difference is explained. It includes cells T1 to T12. The two ends of the battery module are respectively equipped with a first end plate 111 and a first end plate 112. A first heating film 211 is configured at the first end plate 111, and a second heating film 212 is configured at the first end plate 112. A thermocouple (not shown in the figure) is also configured at each of cells T1 to T12.

[0118] For example, in this solution, the temperature difference between cell T1 and cell T12 is set as the cell temperature difference (first temperature difference), and the first heating film 211 is set to heat cell T1, and the second heating film 212 is set to heat cell T12.

[0119] For example, in this solution, the first heating film 211 and the second heating film 212 are respectively connected to a programmable power supply. The programmable power supply adjusts the current output to the first heating film 211 and / or the second heating film 212 to achieve power adjustment of the heating film, thereby controlling the temperature difference between the battery cell T1 and the battery cell T12 to a set battery cell temperature difference, and controlling the battery cell temperature of the battery cell T1 or the battery cell T12 to a set temperature (first temperature).

[0120] S307. Based on cyclic testing, obtain the capacity decay of the first test battery module, the second test battery module, and the third test battery module, and record it as the fourth capacity decay.

[0121] For example, in this solution, multiple rounds of cyclic testing are set up, wherein the first round of cyclic testing corresponds to a first temperature difference and a second temperature difference, and the first temperature and the second temperature remain unchanged in different rounds of cyclic testing;

[0122] For example, taking a two-round cyclical test as an example, combined with Figure 2 In this solution, the cell temperature and cell temperature difference can be controlled in the following ways:

[0123] The temperature difference between cells T1 and T12 in the first test battery module is set to a fixed value T1 (first temperature difference), the temperature difference between the first and second cells in the second test battery module is set to a fixed value T2 (second temperature difference), and the temperature difference between the first and second cells in the third test battery module is set to a fixed value T1.

[0124] The temperature of cell T1 in the first test battery module is set to a fixed value TMAX1 (first temperature), the temperature of the first cell in the second test battery module is set to a fixed value TMAX1, and the temperature of the first cell in the third test battery module is set to a fixed value TMAX2 (second temperature, and the second temperature TMAX2 is set to be greater than the first temperature TMAX1).

[0125] Perform cyclic testing while simultaneously activating the heating control function of the heating film. The current and / or voltage of the heating film are adjusted according to the temperature and temperature difference of the tested battery cell.

[0126] When the temperature difference between cells T1 and T12 is too low, the current of the first heating film 211 and the second heating film 212 is increased; when the temperature difference between cells T1 and T12 is too high, the current of the first heating film 211 and the second heating film 212 is decreased, so that the temperature difference T1 of the cells is stabilized within the set range.

[0127] When the temperature of cell T1 is too low, the current of the first heating film 211 is increased; when the temperature of cell T1 is too high, the current of the first heating film 211 is decreased, so that the temperature of cell T1 is stabilized at the set value.

[0128] When the temperature difference between the first cell and the second cell of the second test battery module is too low, the current of the corresponding heating film is increased; when the temperature difference between the first cell and the second cell of the second test battery module is too high, the current of the corresponding heating film is decreased, so that the temperature difference between the first cell and the second cell of the second test battery module is stabilized within the set range.

[0129] When the temperature of the first cell of the second test battery module is too low, the current of the corresponding heating film is increased; when the temperature of the first cell of the second test battery module is too high, the current of the corresponding heating film is decreased, so that the temperature of the first cell of the second test battery module is stabilized at the set value.

[0130] When the temperature difference between the first and second cells of the third test battery module is too low, the current of the corresponding heating film is increased; when the temperature difference between the first and second cells of the third test battery module is too high, the current of the corresponding heating film is decreased, so that the temperature difference between the first and second cells of the third test battery module is stabilized within the set range.

[0131] When the temperature of the first cell of the third test battery module is too low, the current of the corresponding heating film is increased; when the temperature of the first cell of the third test battery module is too high, the current of the corresponding heating film is decreased, so that the temperature of the first cell of the third test battery module is stabilized at the set value.

[0132] Record the capacity decay (data) of the first test battery module, the second test battery module, and the third test battery module during the cyclic test;

[0133] When conducting the next round of cyclic testing, the temperature difference between cells T1 and T12 is set to a fixed value T3 (first temperature difference), the temperature difference between the first and second cells of the second test battery module is set to a fixed value T4 (second temperature difference), and the temperature difference between the first and second cells of the third test battery module is set to a fixed value T3.

[0134] The temperature of cell T1 in the first test battery module is set to a fixed value TMAX1 (first temperature), the temperature of the first cell in the second test battery module is set to a fixed value TMAX1, and the temperature of the first cell in the third test battery module is set to a fixed value TMAX2 (second temperature).

[0135] Record the capacity decay (data) of the first test battery module, the second test battery module, and the third test battery module during the cyclic test.

[0136] S308. Determine the capacity decay coefficient based on the first capacity decay, the second capacity decay, and the fourth capacity decay.

[0137] For example, in this embodiment, multiple rounds of cyclic testing are performed (the number of rounds is the same as the number of cyclic tests performed on the test group battery modules), and multiple sets of capacity decay can be obtained for a single test battery module (first test battery module, second test battery module, or third test battery module).

[0138] Figure 7 This is a schematic diagram of the capacity decay curve in the embodiment, which is exemplary. Figure 7 The scheme shown can represent the third capacity decay of the first test battery module;

[0139] refer to Figure 7 The test is set to run in three cycles. The three solid lines represent the fourth capacity decay of the battery module in the first test in the three cycles. The three cycles correspond to three first temperature differences ΔT1, ΔT2 and ΔT3.

[0140] The dashed line represents the capacity decay of the control group battery module (the control group battery module does not actively control the cell temperature and cell temperature difference during cycle testing).

[0141] For example, in this scheme, the first capacity decay is used as a benchmark. By fitting the data of (multiple sets) first capacity decay, (multiple sets) second capacity decay, and (multiple sets) fourth capacity decay, a cell-module decay model can be formed. The cell-module decay model can be used to represent the functional relationship between cell temperature difference, maximum cell temperature and capacity decay coefficient.

[0142] Figure 8 This is a schematic diagram of the cell-module attenuation model curve in the embodiment, for reference. Figure 8 For example, after performing multiple rounds of cyclic testing, the following can be obtained: Figure 8 The cell-module attenuation model shown can be represented by the following formula:

[0143]

[0144] In the above formula, ΔT represents the capacity decay coefficient, ΔT represents the cell temperature difference, and Tmax represents the highest cell temperature.

[0145] For example, in this solution, after determining the cell temperature difference (maximum temperature difference) and the highest cell temperature, the lifespan of the target battery module can be determined by using the cell-module attenuation coefficient and the corresponding capacity attenuation coefficient, and then by using the following formula:

[0146]

[0147] In the above formula, Q module Indicates the lifespan of the target battery module. Q represents the capacity decay coefficient. cell This indicates capacity decay.

[0148] relatively Figure 5 The scheme shown includes a first test battery pack, a second test battery pack, and a third test battery pack. The temperature difference in the first test battery pack is designated as the first temperature difference, and the temperature difference in the second test battery pack is designated as the second temperature difference. Simultaneously, the highest cell temperature in both the first and second test battery packs is kept consistent. In both the first and second test battery packs, only the cell temperature difference is used as the single control variable. Similarly, the highest cell temperature in the first test battery pack is designated as the first temperature, and the highest cell temperature in the third test battery pack is designated as the second temperature. Again, the cell temperature difference in both the first and third test battery packs is kept consistent. In both the first and third test battery packs, only the highest cell temperature is used as the single control variable. This approach facilitates the design of multi-round cyclic testing for both cell temperature and the highest cell temperature, thereby improving the efficiency of cyclic testing.

[0149] exist Figure 6 Based on the scheme shown, as one possible implementation, determining the first temperature includes:

[0150] Perform a specified number of charge-discharge cycles on the first test battery module, and record the maximum temperature of the battery cell of the first test battery module as the first temperature.

[0151] Accordingly, in this scheme, determining the second temperature includes:

[0152] Perform a specified number of charge-discharge cycles on the third test battery module, and record the maximum temperature of the cells in the third test battery module as the second temperature.

[0153] For example, in this solution, before conducting cyclic testing, the first temperature and the second temperature for achieving cell temperature control are first determined.

[0154] For example, when determining a first temperature, the first test battery module is subjected to a specified number of charge-discharge cycles (e.g., no more than 5 cycles) when the first temperature is determined.

[0155] After completing a specified number of charge-discharge cycles on the first test battery module, the maximum temperature of the battery cell of the first test battery module is recorded as the first temperature.

[0156] For example, in this solution, the charge-discharge cycle can be completed by referring to any of the test processes specified in the prior art for charge-discharge testing.

[0157] For example, the second temperature is determined in a similar manner to the first temperature. When determining the second temperature, the third test battery module is subjected to a specified number of charge-discharge cycles (e.g., no more than 5 cycles).

[0158] After completing a specified number of charge-discharge cycles on the third test battery module, the maximum temperature of the cells in the third test battery module is recorded as the second temperature.

[0159] Example 2

[0160] This embodiment proposes a capacity attenuation coefficient determination device, including a capacity attenuation coefficient determination unit, which is used for:

[0161] Control the cell temperature difference of the test group battery module, and except for the cell temperature difference, use the same cyclic test conditions to perform cyclic tests on the test group battery module and the control group battery module;

[0162] The capacity decay of the test group battery module is obtained and recorded as the first capacity decay; the capacity decay of the control group battery module is obtained and recorded as the second capacity decay.

[0163] The capacity attenuation coefficient is determined based on the first capacity attenuation and the second capacity attenuation.

[0164] For example, in this embodiment, the capacity attenuation coefficient determination unit can be specifically configured to implement any one of the capacity attenuation coefficient determination methods in Embodiment 1. Its implementation process and beneficial effects are the same as the corresponding content recorded in Embodiment 1, and will not be repeated here.

[0165] Example 3

[0166] Figure 9 A schematic diagram of an electronic device 10 that can be used to implement embodiments of the present invention is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices (e.g., helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0167] like Figure 9As shown, the electronic device 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12 or a random access memory (RAM) 13, communicatively connected to the at least one processor 11. The memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes based on the computer program stored in the ROM 12 or loaded from storage unit 18 into the RAM 13. The RAM 13 may also store various programs and data required for the operation of the electronic device 10. The processor 11, ROM 12, and RAM 13 are interconnected via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0168] Multiple components in electronic device 10 are connected to I / O interface 15, including: input unit 16, such as keyboard, mouse, etc.; output unit 17, such as various types of displays, speakers, etc.; storage unit 18, such as disk, optical disk, etc.; and communication unit 19, such as network card, modem, wireless transceiver, etc. Communication unit 19 allows electronic device 10 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0169] Processor 11 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as the capacity decay factor determination method.

[0170] In some embodiments, the capacity attenuation factor determination method may be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on electronic device 10 via ROM 12 and / or communication unit 19. When the computer program is loaded into RAM 13 and executed by processor 11, one or more steps of the capacity attenuation factor determination method described above may be performed. Alternatively, in other embodiments, processor 11 may be configured to perform the capacity attenuation factor determination method by any other suitable means (e.g., by means of firmware).

[0171] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0172] Computer programs used to implement the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be performed. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0173] In the context of this invention, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0174] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device for displaying information to the user (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor); and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the electronic device. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0175] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as data servers), or computing systems that include middleware components (e.g., application servers), or computing systems that include frontend components (e.g., user computers with graphical user interfaces or web browsers through which users can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., communication networks). Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.

[0176] A computing system can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system to address the shortcomings of traditional physical hosts and VPS services, such as high management difficulty and weak business scalability.

[0177] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A method of determining a capacity fade coefficient, characterized by, The method comprises: controlling the temperature difference of the cells of the battery module in the test group, and not actively controlling the temperature difference of the cells of the battery module in the control group during the cycle test; the same cycle test conditions are used for the battery module in the test group and the battery module in the control group except for the temperature difference of the cells; and obtaining the capacity attenuation of the battery module in the test group, denoted as a first capacity attenuation, and obtaining the capacity attenuation of the battery module in the control group, denoted as a second capacity attenuation; establishing a mapping relationship between the temperature difference of the cells and the capacity attenuation coefficient of the battery module according to the first capacity attenuation and the second capacity attenuation; wherein the mapping relationship is used to determine the life of the target battery module; determining the life of the target battery module according to the capacity attenuation coefficient comprises: determining the maximum temperature difference between the cells of the target battery module, and determining the capacity attenuation coefficient matched therewith according to the maximum temperature difference and the mapping relationship between the temperature difference of the cells and the capacity attenuation coefficient of the battery module; obtaining the working condition parameters of the target battery module, and determining the capacity attenuation of the target battery module according to the working condition parameters; determining the life of the target battery module according to the capacity attenuation coefficient and the capacity attenuation.

2. The capacity fade coefficient determination method according to claim 1, characterized by, After determining the maximum temperature difference between the cells of the target battery module, the method further comprises: if the maximum temperature difference exceeds a temperature difference threshold, controlling the target battery module to cool down; controlling the target battery module to cool down comprises: changing one or more of the heating power, the heating time of the heating film, and adjusting the temperature and flow rate of the cooling liquid of the liquid cooling system.

3. An electronic device, comprising: The method comprises at least one processor, and a memory connected in communication with the at least one processor; the memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor to enable the at least one processor to execute the capacity attenuation coefficient determination method in any one of claims 1-2.

4. A computer readable storage medium, characterized in that, The computer readable storage medium stores computer instructions for enabling the processor to execute the capacity attenuation coefficient determination method in any one of claims 1-2 when executed by the processor.

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