Cyclic aging test method, apparatus and system for battery module

Abstract

The present application relates to a cyclic aging test method, apparatus and system for a battery module, and to the technical field of energy storage tests. The method comprises: in a cyclic aging test, successively performing a charging operation and a discharging operation on a battery module; and, at the end of the discharging operation on the battery module, separately performing discharging operations on battery cells in the battery module. Using the solution of the present embodiment can reduce the test duration of cyclic aging, allowing for cyclic aging tests of short test duration for battery modules.

Description

Battery module cycle aging test method, device and system CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on the Chinese Patent Application No. 2024112394667 entitled "Battery module cycle aging test method, device and system" filed on September 05, 2024, which is incorporated by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of energy storage testing, and in particular to a battery module cycle aging test method, device, system, computer equipment, storage medium and computer program product. BACKGROUND

[0003] With the rapid development of the new energy industry, the energy density of batteries (such as lithium ion batteries) is becoming higher and higher, and the ultimate design (high group margin, thick coating design, etc.) has become the current trend. Although the above measures can significantly improve the use capacity and service life of lithium ion batteries, they also bring about the risk of failure of the battery in the later stage of use, resulting in serious safety problems.

[0004] In order to improve safety, in some cases, systematic risk assessment is carried out during the research and development stage, that is, the single battery and the battery module need to be measured respectively, such as cycle aging measurement, so that they can quickly reach the EOL (End-of-life) state. However, due to the increasing service life of the battery, if the EOL state is to be measured, at least two years of time is required, and the test time is too long. SUMMARY

[0005] Therefore, it is necessary to provide a battery module cycle aging test method, device, system, computer equipment, storage medium and computer program product with short test duration to solve the above technical problems.

[0006] In a first aspect, the present application provides a battery module cycle aging test method, wherein the method comprises, in a cycle aging test, performing the following steps:

[0007] sequentially performing charging operation and discharging operation on the battery module;

[0008] After the discharging operation on the battery module is completed, discharging operation is performed on the battery cell in the battery module.

[0009] Based on the cycle aging test method of this embodiment, in each round of cycle aging test process, after the charging operation and the discharging operation are sequentially performed on the battery module, the cells in the battery module are also taken as the discharge objects, and the cells in the battery module are individually discharged to further individually discharge the cells in the battery module. By further individually discharging the cells in the battery module, the accelerated aging of the cells is realized, which helps the cells and the battery module to reach the EOL state as soon as possible, thereby reducing the test duration of the cycle aging test and realizing the cycle aging test of the battery module with short test duration.

[0010] In some embodiments, the discharging operation of the cells in the battery module individually includes:

[0011] The discharging operation is performed on each cell in the battery module respectively to discharge each cell to a preset voltage.

[0012] Therefore, when the discharging operation of the cells in the battery module is individually performed, each cell in the battery module is taken as an independent discharge object, and the discharging operation is performed on each cell in the battery module respectively, that is, each cell in the battery module can be individually discharged, which realizes the accelerated aging of each cell in the battery module, so that each cell in the battery module can reach the EOL state as soon as possible, and the battery module can also reach the EOL state more quickly, thereby further reducing the test duration of the cycle aging test.

[0013] In some embodiments, the discharging operation is performed on each cell in the battery module respectively to discharge each cell to a preset voltage, including:

[0014] The discharging operation is performed on each cell in the battery module respectively at a preset acceleration rate until each cell is discharged to a preset voltage.

[0015] Based on this embodiment, when the discharging operation is performed on each cell in the battery module, the discharging operation is performed based on the current determined based on the preset acceleration rate of the capacity of the cell, so that the discharging operation is performed based on the range of the preset acceleration rate set in advance, which helps to improve the safety while improving the accelerated aging effect.

[0016] In some embodiments, the preset acceleration rate includes 0.01C-0.1C.

[0017] Based on this embodiment, the preset acceleration rate in this range is used to discharge each cell, which can have better accelerated aging effect and reasonable acceleration duration, which can help to improve the performance of the cycle aging test.

[0018] In some embodiments, the preset acceleration rate includes 0.04C-0.05C.

[0019] Based on this embodiment, discharging each battery cell using a preset acceleration rate in this range can balance the acceleration aging effect and the acceleration time to some extent, which can help to further improve the performance of the cycle aging test.

[0020] In some embodiments, the preset voltage includes 0.5V-1.5V.

[0021] Based on this embodiment, discharging the battery cell to a voltage in this range can achieve accelerated aging of the battery cell, which can have a better accelerated aging effect and can help to improve the performance of the cycle aging test.

[0022] In some embodiments, the preset voltage includes 0.8V-1.0V.

[0023] Based on this embodiment, discharging the battery cell to a voltage in the range of 0.8V-1.0V can achieve accelerated aging of the battery cell, which can have a better accelerated aging effect and can help to further improve the performance of the cycle aging test.

[0024] In some embodiments, the current for discharging the battery module is greater than the current for discharging the battery cell alone.

[0025] Based on this embodiment, the battery module can be charged and discharged by a large current, and the battery cell in the battery module can be discharged alone by a small current. After discharging the battery module by a large current, the battery cell in the battery module can be further discharged alone by a small current to achieve accelerated cycling of the battery cell in the battery module, thereby achieving accelerated cycling of the battery module and realizing cycle accelerated aging of the battery module.

[0026] In some embodiments, the current for charging and / or discharging the battery module is greater than or equal to 50 amperes (A) and less than or equal to 500A, and the current for discharging the battery cell is greater than or equal to 0.5A and less than or equal to 10A.

[0027] In some embodiments, the method further includes monitoring the swelling force of the battery module during the cycle aging test.

[0028] Based on this embodiment, the swelling force of the battery module is also monitored during the cycle aging test, so that the failure risk of the battery module can be evaluated based on the obtained swelling force while testing the cycle aging performance of the battery module, thereby improving the accuracy and safety of the cycle aging test.

[0029] In some embodiments, the expansion force of the battery module is monitored, including:

[0030] A verification battery module is subjected to a cycle aging test simultaneously, the verification battery module being identical to the battery module in model and having at least one cell in the battery module replaced by a battery module in which a pressure sensor is placed;

[0031] The pressure detected by the pressure sensor is taken as the expansion force of the battery module.

[0032] Based on the embodiments, when the expansion force of the battery module is monitored, the expansion force inside the battery module is monitored, so that the change of the expansion force inside the battery module can be monitored, and when the expansion force inside the battery module is monitored, the expansion force inside the verification battery module identical to the battery module in model and having at least one cell in the battery module replaced by a battery module in which a pressure sensor is placed is monitored, so that the detection of the expansion force inside the battery module can be realized without changing the internal structure of the battery module.

[0033] In some embodiments, after the discharging operation of the battery module ends, before the cells in the battery module are individually subjected to a discharging operation, the battery module is further allowed to stand for a first duration.

[0034] After the discharging operation of the battery module ends, the battery module is allowed to stand for a first duration, so that the battery module can gradually tend to a stable state after the discharging operation, and the cells are subjected to a discharging operation for acceleration after the battery module tends to the stable state, which can help improve the stability and reliability of the cycle aging test.

[0035] In some embodiments, the battery module is sequentially subjected to a charging operation and a discharging operation, including:

[0036] The battery module is subjected to a charging operation until the voltage of the battery module reaches an upper limit value of a total module voltage;

[0037] After the second duration, the battery module is subjected to a discharging operation until the voltage of the battery module reaches a lower limit value of the total module voltage.

[0038] Based on the embodiment, when the battery module is sequentially charged and discharged, the battery module is charged to the upper limit value of the total voltage of the module and discharged to the lower limit value of the total voltage of the module, the full charge and full discharge of the battery module are realized, one charging cycle of the battery module is realized, and after the voltage reaches the upper limit value of the total voltage of the module, the battery module is rested for a second time before discharging, which can make the battery module gradually tend to be stable after charging, and the discharging operation is performed on the battery module after the battery module tends to be stable to accelerate, which can help to improve the stability and reliability of the cycle aging test.

[0039] In some embodiments, the charging operation is performed on the battery module until the voltage of the battery module reaches the upper limit value of the total voltage of the module, including:

[0040] The charging operation is performed on the battery module by the constant current charging mode until the voltage of the battery module reaches the upper limit value of the total voltage of the module.

[0041] In some embodiments, the charging operation is performed on the battery module until the voltage of the battery module reaches the upper limit value of the total voltage of the module, including:

[0042] The charging operation is performed on the battery module by the constant voltage mode until the voltage of the battery module reaches the upper limit value of the total voltage of the module.

[0043] In some embodiments, the charging operation is performed on the battery module until the voltage of the battery module reaches the upper limit value of the total voltage of the module, including:

[0044] The charging operation is performed on the battery module by the constant current charging mode until the voltage of the battery module reaches the upper limit value of the total voltage of the module;

[0045] The charging operation is performed on the battery module reaching the upper limit value of the total voltage of the module by the constant voltage mode until the current of the battery module reaches the preset current value.

[0046] In some embodiments, the charging operation is performed on the battery module until the voltage of the battery module reaches the upper limit value of the total voltage of the module, including:

[0047] The charging operation is performed on the battery module by the constant current charging mode at a first current until the voltage of the battery module reaches the preset upper limit value of the voltage;

[0048] The charging operation is performed on the battery module by the constant current charging mode at a second current until the voltage of the battery module reaches the upper limit value of the total voltage of the module, wherein the first current is greater than the second current.

[0049] In some embodiments, the charging operation is performed on the battery module until the voltage of the battery module reaches the upper limit value of the total voltage of the module, including:

[0050] charge the battery module to an upper limit value of a total voltage of the battery module at a preset cycle rate.

[0051] In some embodiments, the preset cycle rate includes one cycle rate.

[0052] In some embodiments, the preset cycle rate includes a plurality of cycle rates, and a sum of target charging electric quantities corresponding to each cycle rate is the charging electric quantity of the battery module.

[0053] The plurality of cycle rates are step cycle rates.

[0054] In a second aspect, the present application further provides a cycle aging test device for a battery module, wherein the device includes:

[0055] The module charge-discharge control module is configured to sequentially perform the charging operation and the discharging operation on the battery module.

[0056] The cell charge-discharge control module is configured to perform the discharging operation on the cells in the battery module individually after the module charge-discharge control module performs one round of the charging operation and the discharging operation on the battery module.

[0057] In a third aspect, the present application further provides a cycle aging test system for a battery module, wherein the test system includes a first charge-discharge device and a second charge-discharge device, the first charge-discharge device is configured to be connected to an input end and an output end of the battery module to be tested, and the second charge-discharge device is configured to be connected to two ends of cells in the battery module to be tested.

[0058] The first charge-discharge device is configured to perform the charging operation and / or the discharging operation on the battery module.

[0059] The second charge-discharge device is configured to perform the discharging operation on the cells in the battery module.

[0060] In some embodiments, the test system further includes a control device in communication connection with the first charge-discharge device and the second charge-discharge device.

[0061] The control device is configured to control the second charge-discharge device to perform the discharging operation on the cells in the battery module after the first charge-discharge device performs one round of the charging operation and the discharging operation on the battery module, and control the first charge-discharge device to sequentially perform the charging operation and the discharging operation on the battery module after the discharging operation on the cells is completed.

[0062] In some embodiments, the test system further includes a verification battery module, the verification battery module being a battery module of the same type as the battery module, and at least one cell in the verification battery module being replaced by a battery module in which a pressure sensor is placed.

[0063] In some embodiments, the verifying battery module further comprises a clamping assembly, the clamping assembly comprising a first clamping part and a second clamping part, the pressure sensor being arranged between the first clamping part and the second clamping part, and the position of the at least one cell in the verifying battery module is replaced by placing the clamping assembly and the pressure sensor.

[0064] In some embodiments, the second charging and discharging device comprises a plurality of charging and discharging units, one charging and discharging unit being connected to two ends of one cell in the battery module to be tested.

[0065] In a fourth aspect, the present application provides a computer device. The computer device comprises a memory and a processor, the memory storing a computer program, and the processor implementing the steps of the method of any one of the above embodiments when executing the computer program.

[0066] In a fifth aspect, the present application provides a computer readable storage medium. The computer readable storage medium stores a computer program, and the computer program, when executed by a processor, implements the steps of the method of any one of the above embodiments.

[0067] In a sixth aspect, the present application provides a computer program product. The computer program product comprises a computer program, and the computer program, when executed by a processor, implements the steps of the method of any one of the above embodiments.

[0068] The above description is only a summary of the technical solutions of the present application. In order to make the technical solutions of the present application more clearly understood and implemented, and in order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application are described in detail. BRIEF DESCRIPTION OF DRAWINGS

[0069] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creating any creative labor. In the drawings:

[0070] Fig. 1 is a flowchart of a cycle aging test method of a battery module in an embodiment;

[0071] Fig. 2 is a flowchart of a cycle aging test method of a battery module in another embodiment;

[0072] Fig. 3 is a flowchart of a cycle aging test method of a battery module in another embodiment;

[0073] Fig. 4 is a flowchart of a cycle aging test method of a battery module in another embodiment;

[0074] Fig. 5 is a flow diagram of monitoring the expansion force of a battery module in one embodiment;

[0075] Fig. 6 is a structural block diagram of a cycle aging test device of a battery module in one embodiment;

[0076] Fig. 7 is a structural block diagram of a cycle aging test system of a battery module in one embodiment;

[0077] Fig. 8 is a structural block diagram of a cycle aging test system of a battery module in another embodiment;

[0078] Fig. 9 is a structural block diagram of a cycle aging test system of a battery module in another embodiment;

[0079] Fig. 10 is a partial top view of a verification battery module in one embodiment;

[0080] Fig. 11 is an internal structural diagram of a computer device in one embodiment.

[0081] Fig. 10 is a partial top view of a verification battery module in one embodiment; DETAILED DESCRIPTION

[0082] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the protection scope of the present application.

[0083] The embodiments of the technical scheme of the present application will be described in detail below in conjunction with the accompanying drawings. The following embodiments are only used to make the technical scheme of the present application clearer, and therefore only serve as examples, and should not be used to limit the protection scope of the present application.

[0084] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments of the present application and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion.

[0085] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise explicitly and specifically limited.

[0086] Reference herein to "embodiments" means that the particular features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily independent or alternative to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0087] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after it.

[0088] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two), and similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0089] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "connection" and the like should be broadly understood, for example, it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium; it can be internal communication of two elements or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0090] At present, in order to be able to make a systematic risk assessment on the battery, some evaluation methods are to test the cycle aging of the battery, so that the battery quickly reaches the EOL state, that is, it is necessary to respectively measure the single battery and the battery module, such as cycle aging test, so that it quickly reaches the EOL state. However, as the service life of the battery is getting higher and higher, if it is measured to the EOL state, at least two years of time is needed, and the test time is too long.

[0091] It is found through research that the battery module includes a plurality of battery cells arranged in series and / or parallel, and during the cycle aging test, after the battery module is discharged, a certain amount of electricity may still remain in the battery cells in the battery module, the states of the battery cells are not uniform, that is, the battery cells in the battery module may not be in the state of the lowest electricity, and therefore, after the battery module is discharged, the battery cells in the battery module can be further discharged to accelerate the aging of the battery cells in the battery module, thereby achieving the accelerated aging of the battery module, and thus achieving the shortening of the aging cycle test and realizing the cycle aging test with short test time.

[0092] Therefore, the embodiment of the present application provides a cycle aging test method of a battery module, which can be applied to an application environment of cycle aging test of a battery module. The cycle aging test method of the battery module provided by the embodiment of the present application can perform a plurality of rounds of cycle aging test until the battery module or each battery cell of the battery module reaches an EOL state.

[0093] As shown in FIG. 1, the cycle aging test method of the battery module provided by the embodiment of the present application performs the following steps in one round of cycle aging test:

[0094] Step S101: sequentially performing a charging operation and a discharging operation on the battery module.

[0095] The charging operation refers to the process of storing electrical energy to the battery module when the battery module is in a charging state. The discharging operation refers to the process of discharging electrical energy from the battery module when the battery module is in a discharging state.

[0096] By sequentially performing the charging operation and the discharging operation on the battery module, one charging and discharging cycle of the battery module is realized.

[0097] Step S102: after the discharging operation on the battery module is completed, separately performing a discharging operation on the battery cells in the battery module.

[0098] The discharging operation on the battery cells refers to the process of releasing electrical energy in the battery cells. The separate discharging operation on the battery cells in the battery module refers to discharging a single battery cell as an object, and only one battery cell is discharged in one discharging process. It should be understood that if a plurality of battery cells in the battery module are separately discharged, the discharging processes of the plurality of battery cells are performed separately, for example, the discharging operation on the next battery cell can be performed after the discharging operation on one battery cell is completed, or the discharging operation on these battery cells can be simultaneously performed by different discharging devices.

[0099] After the charging and discharging operation of the battery module is completed, one cycle of charging and discharging of the battery module is completed, but after the discharging operation of the battery module is completed, the battery cells in the battery module can still have some residual power, so that the battery cells in the battery module can be separately discharged again, so that the residual power in the battery cells can be discharged, so that the accelerated aging of the battery cells can be realized, and the accelerated aging of the battery module can be realized.

[0100] Based on the cycle aging test method of the embodiment, after the charging operation and the discharging operation of the battery module are sequentially performed in a cycle of the cycle aging test, the battery cells in the battery module are discharged after the discharging operation, and the battery cells in the battery module are separately discharged after the discharging operation. The battery cells in the battery module are further separately discharged to further separately discharge the battery cells in the battery module, so that the accelerated aging of the battery cells is realized, which helps the battery cells and the battery module to reach the EOL state as soon as possible, thereby reducing the test time of the cycle aging test on the basis of the cycle aging test. The cycle aging test of the battery module with short test time is realized.

[0101] In the embodiment, all the battery cells in the battery module can be separately discharged.

[0102] Accordingly, in some embodiments, referring to FIG. 2, the battery cells in the battery module are separately discharged, including:

[0103] Step S1020: Discharge each battery cell in the battery module to a preset voltage.

[0104] In the embodiment, all the battery cells in the battery module can be separately discharged.

[0105] The specific value of the preset voltage is not limited, and in some embodiments, the preset voltage can be set based on the capacity voltage range of the battery cell.

[0106] Therefore, when the battery cells in the battery module are individually discharged, each battery cell in the battery module is taken as an independent discharge object, and each battery cell in the battery module is individually discharged, that is, each battery cell in the battery module can be individually discharged, thereby accelerating the aging of each battery cell in the battery module, so that each battery cell in the battery module can reach the EOL state as soon as possible, and then the battery module can also reach the EOL state more quickly, thereby further reducing the test duration of the cycle aging.

[0107] When each battery cell in the battery module is discharged, the specific discharge operation mode is not limited, and the following examples are illustrated in combination with several modes.

[0108] In some embodiments, referring to FIG. 3, each battery cell in the battery module is individually discharged to a preset voltage, including:

[0109] Step S10211: Discharge each battery cell in the battery module at a preset acceleration rate until each battery cell is discharged to a preset voltage.

[0110] The preset acceleration rate refers to a rate determined with respect to the capacity of the battery module. The current can be determined by the capacity of the battery module and the preset acceleration rate. The specific current can be the product of the preset acceleration rate and the capacity of the battery module. Taking the capacity of the battery module as C and the preset acceleration rate as k as an example, the current for discharging the battery cell is k*C. The capacity of the battery module can be the rated capacity of the battery module or the design capacity of the battery module. In the embodiments of the present application, the capacity C of the battery module can also be the actual capacity of the battery module, for example, the discharge capacity value can be tested during the discharging operation of the battery module after the charging operation of the battery module, and the discharge capacity value is taken as the actual capacity of the battery module. In some embodiments, the preset acceleration rate can be adjusted once for each test of the discharge capacity value, thereby reducing the possibility of lithium precipitation.

[0111] Taking the tested discharge capacity value as the capacity of the battery module as an example, the current for discharging the battery cell can be expressed as k*Cn, wherein n represents the number of times of testing the discharge capacity value, and Cn represents the capacity of the battery module obtained by the nth test.

[0112] The specific value of the preset voltage is not limited and can be determined in combination with the performance of the battery cell and the test requirement, for example, the preset voltage in some specific examples can be set to 1.0V.

[0113] Based on this embodiment, when each battery cell in the battery module is individually discharged, the current is determined based on the preset acceleration rate of the capacity of the battery module, so that the discharge operation is based on the preset acceleration rate range, which helps to improve the safety while improving the acceleration aging effect.

[0114] The specific range of the preset acceleration rate is not limited. Through experimental testing, it is found that the lower the preset acceleration rate, the more obvious the effect of accelerated aging, but the longer the time of accelerated aging. The higher the preset acceleration rate, the worse the effect of accelerated aging, but the shorter the time of accelerated aging. Through experimental testing, it is found that when the preset acceleration rate is 0.01C-0.1C, it can have a good effect of accelerated aging, and the time of accelerated aging can be significantly shortened compared with the scheme without discharging the battery cell.

[0115] Based on this embodiment, the preset acceleration rate in this range is used to individually discharge each battery cell, which can have a better effect of accelerated aging and a reasonable acceleration time, which can help to improve the performance of the cycle aging test.

[0116] Through further research and testing, it is found that when the preset acceleration rate is in the range of 0.04C-0.05C, the effect of accelerated aging can be significantly improved, and the time of accelerated aging can be further shortened, which can achieve a certain balance between the effect of accelerated aging and the acceleration time.

[0117] Based on this embodiment, the preset acceleration rate in this range is used to discharge each battery cell, which can balance the effect of accelerated aging and the acceleration time to a certain extent, which can help to further improve the performance of the cycle aging test.

[0118] The specific range of the preset voltage is not limited. Generally, the smaller the value of the preset voltage, the better the effect of accelerated aging, but the value of the preset voltage is too small, which can easily cause serious overcharging. Through research and testing, it is found that when the preset voltage is in the range of 0.5V-1.5V, it can have a better effect of accelerated aging, which can help to improve the performance of the cycle aging test. Through further research and testing, it is found that when the preset voltage is in the range of 0.8V-1.0V, it can have a better effect of accelerated aging, and the overcharging can be within an acceptable range, which can help to further improve the performance of the cycle aging test.

[0119] In some embodiments, the current for discharging the battery module is greater than the current for individually discharging the battery cell.

[0120] The battery module is formed by a plurality of battery cells in series and / or parallel connection, and thus, the battery module can be charged and discharged with a large current to rapidly cycle the battery module, and the battery cells can be discharged with a small current to cycle and age the battery cells while maintaining the performance of the battery cells.

[0121] In some embodiments, the current for charging and / or discharging the battery module is greater than or equal to 50 A and less than or equal to 500 A, and the current for discharging the battery cells alone is greater than or equal to 0.5 A and less than or equal to 10 A.

[0122] Based on the embodiments, the battery module can be charged and discharged with a large current, and the battery cells in the battery module can be discharged alone with a small current to further discharge the battery cells in the battery module after the battery module is discharged with a large current, thereby accelerating the cycling of the battery cells in the battery module and achieving accelerated cycling and aging of the battery module.

[0123] In some embodiments, referring to FIG. 4, the method further includes:

[0124] Step S103: In the cycle aging test, the swelling force of the battery module is monitored.

[0125] The swelling force refers to the force generated on the battery shell due to the generation of gas and the volume change of the battery material caused by the internal chemical reaction of the battery during charging and discharging. The swelling force of the battery has a certain impact on the performance and service life of the battery. If the swelling force is too high, it will cause excessive pressure on the battery shell, leading to deformation or even rupture of the battery shell, thereby affecting the performance and service life of the battery.

[0126] With the increasing energy density of the battery and the trend of extreme design (high group margin, thick coating design, etc.), the swelling force of the battery becomes larger in the later use stage. Excessive swelling force can cause the structure frame (side plate structure, end plate structure, and weld joint) of the lithium ion battery module to fail, resulting in serious safety hazards.

[0127] In the embodiments of the present application, the swelling force of the battery module is monitored, which can be used to evaluate the change in performance of the battery module in the cycle aging test based on the monitored swelling force, and can also be used to evaluate the service life of the battery module. The swelling force can be used to determine whether the battery module reaches the EOL state, and the safety of the battery module in the cycle aging test can be confirmed and improved based on this.

[0128] Based on the embodiment, the expansion force of the battery module is also monitored in the cycle aging test, so that the cycle aging performance of the battery module is tested, and the failure risk of the battery module is evaluated based on the obtained expansion force, thereby improving the accuracy and safety of the cycle aging test.

[0129] The way of monitoring the expansion force of the battery module is not limited. In some embodiments, a pressure sensor can be arranged on the outside of the battery module, and the pressure detected by the pressure sensor arranged on the outside is taken as the expansion force of the battery module.

[0130] In some embodiments, the expansion force of the battery module can also be detected by detecting the expansion force of the internal cells of the battery module. However, the battery module is a module arranged as a whole, and a pressure sensor is usually not arranged in the internal cells of the battery module. If a pressure sensor is arranged in the internal cells of the battery module after the production of the battery module to be tested, the overall structure of the battery module will be affected.

[0131] Therefore, in some embodiments, referring to FIG. 5, the monitoring of the expansion force of the battery module in step S103 can include:

[0132] Step S1031: synchronously performing cycle aging test on the verification battery module, the verification battery module being a battery module of the same type as the battery module, and at least one cell in the verification battery module being replaced by a pressure sensor.

[0133] The verification battery module is of the same type as the battery module to be tested, but at least one cell in the verification battery module is removed, and a pressure sensor is arranged at the original position of the removed cell. The number of removed cells can be determined based on the size of the pressure sensor.

[0134] Step S1032: taking the pressure detected by the pressure sensor as the expansion force of the battery module.

[0135] Generally, the size of the pressure sensor is not large, and therefore, the number of removed cells is also small. The battery module usually contains tens or even hundreds of cells. By synchronously performing cycle aging test on the battery module to be tested and the verification battery module, the charge and discharge states of the battery module to be tested and the verification battery module are the same, and therefore, the expansion force in the verification battery module is almost the same as the expansion force of the battery module to be tested. The expansion force measured in the verification battery module can be taken as the expansion force of the battery module to be tested.

[0136] Based on the embodiment, when monitoring the expansion force of the battery module, the expansion force inside the battery module is monitored, so that the change of the expansion force inside the battery module can be monitored, and when monitoring the expansion force inside, the expansion force inside the verification battery module in which the pressure sensor is placed is monitored by monitoring the same model of the battery module and the position of at least one battery cell in the battery module, so that the detection of the expansion force inside the battery module can be realized without changing the internal structure of the battery module.

[0137] In some embodiments, after the discharging operation of the battery module in step S101 ends, before the single discharging operation of the battery cell in the battery module in step S102, the battery module is further placed for a first duration.

[0138] The specific duration of the first duration is not limited, and in some embodiments, the first duration can be set to 10 minutes. It can be understood that in other embodiments, the first duration can also be set to other durations.

[0139] After the discharging operation of the battery module ends, by placing the battery module for a first duration, the battery module can gradually tend to a stable state after the discharging operation, and the discharging operation of the battery cell is performed to accelerate after the battery module tends to be stable, which can help improve the stability and reliability of the cycle aging test.

[0140] In some embodiments, the battery module is sequentially subjected to a charging operation and a discharging operation, comprising:

[0141] The battery module is subjected to a charging operation until the voltage of the battery module reaches a module total voltage upper limit value;

[0142] After being placed for a second duration, the battery module is subjected to a discharging operation until the voltage of the battery module reaches a module total voltage lower limit value.

[0143] The module total voltage upper limit value refers to the total voltage upper limit value of the battery module. The module total voltage upper limit value can be determined based on the number of battery cells contained in the battery module and the series-parallel connection relationship of the battery cells contained in the battery module. For example, if the battery cells contained in the battery module are in series connection, the module total voltage upper limit value of the battery module is N*Vmax, where N is the number of battery cells contained in the battery module, and Vmax is the upper limit value of the voltage of each battery cell.

[0144] The module total voltage lower limit value refers to a total voltage lower limit value of the battery module. The module total voltage lower limit value can be determined based on the number of battery cells included in the battery module and the series-parallel connection relationship of the battery cells included in the battery module. Taking an example in which the battery cells included in the battery module are all in a series connection relationship, the module total voltage lower limit value of the battery module is N*Vmin, where N is the number of battery cells included in the battery module, and Vmin is the voltage lower limit value of each battery cell.

[0145] The specific duration of the second duration is not limited, and in some embodiments, the second duration can be set to 30 minutes. It can be understood that in other embodiments, the second duration can also be set to other durations.

[0146] Based on this embodiment, when the battery module is sequentially subjected to charging and discharging operations, the battery module is charged to a voltage of the battery module reaching a module total voltage upper limit value and is discharged to a voltage of the battery module reaching a module total voltage lower limit value, full charging and full discharging of the battery module are achieved, one charging cycle of the battery module is achieved, and after charging to a voltage reaching the module total voltage upper limit value, the battery module is subjected to a discharging operation for a second duration, which can enable the battery module to gradually tend to a stable state after the charging operation, and the discharging operation is performed on the battery module after the battery module tends to the stable state to accelerate, which can help improve the stability and reliability of the cycle aging test.

[0147] The specific manner in which the battery module is subjected to the charging operation until the voltage of the battery module reaches the module total voltage upper limit value is not limited, and some of the manners are exemplarily described below.

[0148] In some embodiments, the battery module is subjected to the charging operation until the voltage of the battery module reaches the module total voltage upper limit value, including:

[0149] The battery module is subjected to the charging operation by the constant current charging mode until the voltage of the battery module reaches the module total voltage upper limit value.

[0150] The constant current charging mode (also referred to as the CC (Constant Current) mode) refers to a charging mode in which the current remains unchanged and the voltage gradually increases during the charging process. During the charging operation by the constant current charging mode, the current remains unchanged and the voltage gradually increases. The battery module is subjected to the charging operation by the constant current charging mode, so that the charging of the battery module can be achieved by a stable current.

[0151] In some embodiments, the battery module is subjected to the charging operation until the voltage of the battery module reaches the module total voltage upper limit value, including:

[0152] The battery module is subjected to the charging operation by the constant voltage mode until the voltage of the battery module reaches the module total voltage upper limit value.

[0153] The constant voltage mode (also referred to as CV mode) refers to a charging mode in which the voltage remains unchanged during the charging process. During the charging operation by the constant voltage mode, the voltage remains unchanged and the current gradually decreases, and during the discharging operation by the constant voltage mode, the current first decreases and then increases. The battery module is charged by the constant voltage mode, so that the charging of the battery module can be realized by a stable voltage.

[0154] In some embodiments, the battery module is charged until the voltage of the battery module reaches the upper limit value of the total module voltage, including:

[0155] The battery module is charged by the constant current charging mode until the voltage of the battery module reaches the upper limit value of the total module voltage;

[0156] The battery module reaching the upper limit value of the total module voltage is charged by the constant voltage mode until the current of the battery module reaches the preset current value.

[0157] The voltage of the battery module reaching the upper limit value of the total module voltage means that the voltage of the battery module increases to be greater than or equal to the upper limit value of the total module voltage. The current of the battery module reaching the preset current value means that the current of the battery module decreases to be less than or equal to the preset current value.

[0158] Based on the embodiment, when the battery module is charged, the battery module is charged in combination with the constant current charging mode and the constant voltage charging mode, so that the current remains constant during the charging process, the voltage remains constant after charging to the upper limit voltage, and finally the current gradually decreases to the preset current value after charging. Because the actual voltage of the battery module will fall back to a certain extent after being charged by the constant current charging mode, further charging the battery module in combination with the constant voltage charging mode can achieve sufficient charging of the battery module, and can further promote the acceleration of the aging cycle on this basis.

[0159] In some embodiments, the battery module is charged until the voltage of the battery module reaches the upper limit value of the total module voltage, including:

[0160] The battery module is charged by the constant current charging mode at a first current until the voltage of the battery module reaches a preset upper limit value of the voltage;

[0161] The battery module is charged by the constant current charging mode at a second current until the voltage of the battery module reaches the upper limit value of the total module voltage, wherein the first current is greater than the second current.

[0162] The specific values of the first current and the second current are not limited, as long as the battery module can be quickly charged and then slowly charged with a small current after the quick charging.

[0163] Based on this embodiment, when charging the battery module, the battery module is first charged with a large first current through the constant current charging mode, so that the battery module can be quickly charged, and further charging the battery module with a small second current can reduce the voltage drop of the battery module after charging is completed, which can help improve the charging performance.

[0164] In some embodiments, the battery module is charged until the voltage of the battery module reaches the upper limit of the total module voltage, including:

[0165] The battery module is charged to the upper limit of the total module voltage at a preset cycle rate.

[0166] The preset cycle rate is a rate determined with respect to the capacity of the battery module, and the current can be determined by the capacity of the battery module and the preset cycle rate. The specific current can be the product of the preset cycle rate and the capacity of the battery module. Taking the capacity of the battery module as C and the preset cycle rate as j as an example, the current for charging the battery module is j*C.

[0167] The preset cycle rate is not limited, for example, the preset cycle rate in some embodiments can be 0.33C-3.0C when charging the battery module through the constant current charging mode.

[0168] The preset cycle rate can be one or more than two. Taking an example of a preset cycle rate including one cycle rate, the preset cycle rate in a specific example can be set to 1.0C.

[0169] In some embodiments, the preset cycle rate includes multiple cycle rates, and the sum of the target charging capacities corresponding to each cycle rate is the charging capacity of the battery module. That is, after charging to the target charging capacity corresponding to each cycle rate, the next cycle rate is switched for charging. Taking an example of setting three cycle rates, the battery module can be charged by the first cycle rate, only the capacity of the battery module reaches K%. Then switch to charge the battery module by the second cycle rate until the capacity of the battery module reaches (K+L)%, that is, charge L% of the capacity by the second cycle rate. Then switch to charge by the third cycle rate until the capacity of the battery module reaches 100%, that is, charge (100-K-L)% of the capacity by the third cycle rate.

[0170] In some embodiments, the plurality of cycle rates can be step cycle rates. For example, the plurality of cycle rates in some embodiments can include 3.0C, 2.0C, 1.5C and 1.0C. The target charge amount corresponding to each cycle rate, for example, the target charge amount corresponding to the cycle rates 3.0C, 2.0C, 1.5C and 1.0C in some specific examples can be 10%, 10%, 10% and 70% respectively.

[0171] In the process of charging the battery module as described above, the manner of determining that the voltage of the battery module reaches the upper limit of the total voltage of the module is not limited.

[0172] In some embodiments, the total voltage value of the battery module can be measured, and when the total voltage value of the battery module reaches the upper limit of the total voltage of the module (e.g., N*Vmax), it can be determined that the voltage of the battery module reaches the upper limit of the total voltage of the module.

[0173] However, in actual cycling, due to the consistency difference of the battery cells, if only the total voltage is used as the cutoff, safety problems such as overcharging and overdischarging of the battery cells are likely to occur.

[0174] Therefore, in some other embodiments, the voltage values of all single battery cells can be monitored through the low-voltage wiring harness, and when the voltage value of any single battery cell reaches the upper limit value Vmax, it can be determined that the voltage of the battery module reaches the upper limit of the total voltage of the module.

[0175] In some other embodiments, the total voltage value of the battery module and the voltage values of the single battery cells can be detected at the same time, and when the total voltage value of the battery module reaches the upper limit of the total voltage of the module, or the voltage value of any single battery cell reaches the upper limit value Vmax, that is, as long as any one of the two conditions is met, it can be determined that the total voltage value of the battery module reaches the upper limit of the total voltage of the module.

[0176] Therefore, by combining the voltage values of the battery cells to determine whether the voltage of the battery module reaches the upper limit of the total voltage of the module, the problem of overcharging of the battery cells caused by only using the total voltage of the battery module as the cutoff for charging operation can be reduced.

[0177] The specific manner of discharging the battery module until the voltage of the battery module reaches the lower limit of the total voltage of the module is not limited, and some of the manners are exemplified below.

[0178] In some embodiments, discharging the battery module until the voltage of the battery module reaches the lower limit of the total voltage of the module includes:

[0179] The battery module is discharged by a constant current discharge mode (also referred to as a DC mode) until the voltage of the battery module reaches a lower limit value of a total voltage of the module. During the discharging operation by the constant current discharge mode, the current remains unchanged and the voltage gradually decreases. The battery module is discharged by the constant current discharge mode, so that the discharging of the battery module can be achieved by a stable current.

[0180] In some embodiments, the discharging rate can be 0.33C-3.0C when the constant current discharge is performed. In one specific example, the constant current discharge can be performed at a rate of 0.1C.

[0181] In the above discharging operation of the battery module, the manner of determining that the voltage of the battery module reaches the lower limit value of the total voltage of the module is not limited.

[0182] In some embodiments, the total voltage value of the battery module can be measured, and when the total voltage value of the battery module reaches the lower limit value of the total voltage of the module (e.g., N*Vmin), it can be determined that the voltage of the battery module reaches the lower limit value of the total voltage of the module.

[0183] However, in actual cycling, due to the consistency difference of the battery cells, if only the total voltage is used for cutoff, safety problems such as overcharging and overdischarging of the battery cells are prone to occur.

[0184] Therefore, in some other embodiments, the voltage values of all single battery cells can be monitored through a low-voltage wiring harness, and when the voltage value of any single battery cell reaches the lower limit value Vmin, it can be determined that the voltage of the battery module reaches the lower limit value of the total voltage of the module.

[0185] In some other embodiments, the total voltage value of the battery module and the voltage values of the single battery cells can be detected at the same time, and when the total voltage value of the battery module reaches the lower limit value of the total voltage of the module or the voltage value of any single battery cell reaches the lower limit value Vmin, as long as any one of the two conditions is met, it can be determined that the total voltage value of the battery module reaches the lower limit value of the total voltage of the module.

[0186] Therefore, in combination with the voltage values of the battery cells, the determination of whether the voltage of the battery module reaches the lower limit value of the total voltage of the module can reduce the problem of overdischarging of the battery cells caused by the cutoff of the discharging operation only by the total voltage of the battery module.

[0187] In some embodiments, the above method can further include: when the number of cycle aging tests reaches a preset number of cycles, performing a capacity test on the battery module, i.e., testing the battery module capacity of the battery module.

[0188] The specific value of the preset number of rounds is not limited, for example, it can be 0 times (i.e. before testing), 50 times, 100 times, etc., but is not limited thereto, and can be determined in combination with actual testing requirements.

[0189] The way of testing the battery module capacity in one embodiment can include: testing the battery module capacity of the battery module by charging and discharging the battery module. Thus, the battery capacity of the battery module can be obtained by charging and discharging the battery module.

[0190] In some embodiments, testing the battery module capacity of the battery module by charging and discharging the battery module includes:

[0191] Charging the battery module until the voltage of the battery module reaches the upper limit value of the total module voltage;

[0192] After resting for a first predetermined length of time, discharging the battery module until the voltage of the battery module reaches the lower limit value of the total module voltage;

[0193] Obtaining the battery module capacity of the battery module based on the discharge amount of the battery module during discharging.

[0194] Based on this embodiment, when testing the battery module capacity of the battery module, the battery module is charged to the voltage of the battery module reaching the upper limit value of the total module voltage, and then the battery module is discharged to the voltage of the battery module reaching the lower limit value of the total module voltage. The full charge and full discharge of the battery module are combined with the discharge amount during discharging to obtain the battery module capacity of the battery module. This can make the measured battery module capacity be the actual capacity of the battery module, and can improve the accuracy of the measured battery module capacity. After charging to the voltage reaching the upper limit value of the total module voltage, the battery module is discharged before resting for a first predetermined length of time. This can make the battery module gradually tend to a stable state after the charging operation, and the battery module is discharged after the battery module tends to a stable state, and the battery module capacity is tested accordingly. This can further help to improve the accuracy of the measured battery module capacity.

[0195] The way of charging the battery module until the voltage of the battery module reaches the upper limit value of the total module voltage can be the same as the way of charging described above, and will not be described here.

[0196] It should be understood that after the cycle aging test has started, when the number of cycle aging tests reaches the preset number of rounds, the battery module capacity of the battery module can also be measured when the battery module is discharged after the voltage of the battery module is charged to the upper limit value of the total module voltage during the cycle aging test of the battery module.

[0197] In some embodiments, after measuring the battery module capacity of the battery module, the preset acceleration rate can be adjusted simultaneously in combination with the measured battery module capacity, and the specific adjustment manner is not limited.

[0198] Based on the above-described embodiments, the following is illustrated in combination with some specific examples. When a cycle aging test needs to be performed on a battery module to be tested, a battery module of the same model as the battery module to be tested is obtained, and at least one cell in the middle of the battery module is removed, and a pressure sensor is placed at the position where the cell is removed, thereby obtaining a verification battery module. In the case where there is a gap between the pressure sensor and the adjacent cell or the gap is greater than a preset threshold, a clamping assembly can also be provided to fix the pressure sensor. Subsequently, the battery module to be tested and the verification battery module are both connected to a charge-discharge system, and the cycle aging test is performed synchronously. During the cycle aging test, the expansion force measured by the pressure sensor in the verification battery module is used as the expansion force of the battery module to be tested.

[0199] When the cycle aging test is performed on the battery module, the battery module to be tested and the verification battery module are tested synchronously, the cycle aging test of the verification battery module can be used to verify the cycle aging test process of the battery module to be tested, and the expansion force obtained by the verification battery module is used as the expansion force of the battery module to be tested. During the cycle aging test, the monitored expansion force is recorded synchronously, and the performance and life of the battery module to be tested are evaluated based on the expansion force, which will not be described in detail in the following examples.

[0200] When the cycle aging test is performed on the battery module, multiple cycles of the cycle test process can be performed. In one specific example, one cycle of the cycle aging test process can be performed as follows.

[0201] First, the aging cycle process of the battery module is performed. The process in one specific example can be as follows.

[0202] First, the battery module is rested for a certain period of time, for example, 30 minutes, and then the battery module is charged until the voltage of the battery module reaches the upper limit of the total voltage of the battery module; for example, for a battery module in series mode, the upper limit of the total voltage of the battery module is Vmax*N. Then, the battery module is rested for a second period of time, for example, 30 minutes, and then the battery module is discharged until the voltage of the battery module reaches the lower limit of the total voltage of the battery module; for example, for a battery module in series mode, the lower limit of the total voltage of the battery module is Vmin*N. Then, the battery module is rested for a first period of time, for example, 10 minutes.

[0203] Secondly, after the aging cycle process of the battery module is completed, an acceleration process is performed on the battery cells in the battery module. For example, each battery cell in the battery module is discharged individually until the voltage of each battery cell reaches a preset voltage, such as 1.0V.

[0204] The above-mentioned each round of cycle aging test process is repeated until a preset number of cycles is reached or the battery module reaches an EOL state.

[0205] It should be understood that, in the above-mentioned cycle aging test process, when the battery cells in the battery module are discharged for accelerated aging, the temperature for accelerated aging can be set to further enhance the acceleration effect of cycle aging. In some embodiments, the ambient temperature of the cycle aging test can be set to 35-45°C (degrees Celsius), denoted as T, so that the acceleration effect of high temperature can be achieved. Since the battery module also generates heat during charging and discharging, the temperature also rises to a certain extent, so a cooling device can be configured at the same time. When the ambient temperature T is greater than a preset value (such as 5°C), the cooling device is turned on to cool the battery module, reducing the possibility of excessive temperature affecting safety. When the ambient temperature T is lower than the preset value (such as 5°C), the cooling device is turned off to maintain the battery module in a high-temperature environment to achieve the acceleration effect of high temperature.

[0206] It should be understood that, when capacity testing is required, in order to improve the accuracy of capacity testing, the test environment temperature can be set to a normal ambient temperature, such as 25°C or a range adjacent thereto, but not limited thereto.

[0207] The cycle aging test method of the battery module according to the embodiments of the present application can achieve accelerated cycle aging test of the battery module. It is found through actual tests that, by combining discharging the battery module and then discharging the battery cells in the battery module for accelerated aging, the cycle aging test time can be greatly shortened. It is found through tests that the time required for the battery module to cycle age to an EOL state can be shortened from more than two years to within three months. Moreover, by discharging the battery cells in the battery module individually to accelerate cycle aging, all the single batteries in the battery module can have the same accelerated aging effect, and when the EOL state is reached, the SOH (State of Health) consistency difference of all the single batteries is reduced. It is found through actual tests that the cycle aging test method according to the embodiments of the present application can achieve accelerated aging of the module capacity and the swelling force of the battery module, and the growth trend of the swelling force is consistent with the growth trend of normal cycles.

[0208] It should be understood that although the steps in the flowcharts involved in the embodiments described above are shown in sequence according to the arrows, the steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, the execution of the steps is not strictly limited in sequence, and the steps can be executed in other sequences. Moreover, at least some of the steps in the flowcharts involved in the embodiments described above can include multiple steps or multiple stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution sequence of the steps or stages is not necessarily sequential, but can be executed alternately or alternately with at least part of other steps or steps or stages in other steps.

[0209] Based on the same inventive concept, the embodiments of the present application also provide a battery module cycle aging test device for implementing the battery module cycle aging test method described above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme described in the above method, so the specific limitations in one or more battery module cycle aging test device embodiments provided below can refer to the limitations of the battery module cycle aging test method described above, which will not be repeated here.

[0210] In one embodiment, as shown in FIG. 6, a battery module cycle aging test device is provided, which includes a module charge-discharge control module 601 and a cell charge-discharge control module 602, wherein:

[0211] The module charge-discharge control module 601 is configured to sequentially perform charging operation and discharging operation on the battery module.

[0212] The cell charge-discharge control module 602 is configured to perform discharging operation on the cells in the battery module individually after the module charge-discharge control module performs a round of charging operation and discharging operation on the battery module.

[0213] In some embodiments, the cell charge-discharge control module 602 is configured to perform discharging operation on each cell in the battery module respectively to discharge each cell to a preset voltage.

[0214] In some embodiments, the cell charge-discharge control module 602 is configured to perform discharging operation on each cell in the battery module respectively at a preset acceleration rate until the power of each cell is discharged to a preset voltage.

[0215] In some embodiments, the preset acceleration rate includes 0.01C-0.1C.

[0216] In some embodiments, the preset acceleration rate includes 0.04C-0.05C.

[0217] In some embodiments, the preset voltage includes 0.5V-1.5V.

[0218] In some embodiments, the preset voltage includes 0.8V-1.0V.

[0219] In some embodiments, the current of the battery module discharging operation of the module charging and discharging control module 601 is greater than the current of the single cell discharging operation of the cell charging and discharging control module 602.

[0220] In some embodiments, the current of the battery module charging and / or discharging operation of the module charging and discharging control module 601 is greater than or equal to 50A and less than or equal to 500A, and the current of the single cell discharging operation of the cell charging and discharging control module 602 is greater than or equal to 0.5A and less than or equal to 10A.

[0221] In some embodiments, the device further comprises:

[0222] The expansion force monitoring module is configured to monitor the expansion force of the battery module in the cycle aging test.

[0223] In some embodiments, the device synchronously performs the cycle aging test on the verification battery module, and the verification battery module is a battery module of the same type as the battery module, and at least one cell in the battery module is replaced by a battery module with a pressure sensor.

[0224] The expansion force monitoring module takes the pressure detected by the pressure sensor as the expansion force of the battery module.

[0225] In some embodiments, the module charging and discharging control module 601 is configured to, after the end of the discharging operation of the battery module, place the battery module for a first duration.

[0226] In some embodiments, the module charging and discharging control module 601 is configured to perform a charging operation on the battery module until the voltage of the battery module reaches the upper limit of the total module voltage, and perform a discharging operation on the battery module after a second duration, until the voltage of the battery module reaches the lower limit of the total module voltage.

[0227] In some embodiments, the module charging and discharging control module 601 is configured to perform a charging operation on the battery module by a constant current charging mode until the voltage of the battery module reaches the upper limit of the total module voltage.

[0228] In some embodiments, the module charging and discharging control module 601 is configured to perform a charging operation on the battery module by a constant voltage mode until the voltage of the battery module reaches the upper limit of the total module voltage.

[0229] In some embodiments, the module charge and discharge control module 601 is configured to perform a charging operation on the battery module in a constant current charging mode until the voltage of the battery module reaches a preset upper limit value of the voltage of the battery module; and perform a charging operation on the battery module in a constant voltage mode until the current of the battery module reaches a preset current value.

[0230] In some embodiments, the module charge and discharge control module 601 is configured to perform a charging operation on the battery module in a constant current charging mode at a first current until the voltage of the battery module reaches a preset upper limit value of the voltage of the battery module; and perform a charging operation on the battery module in a constant current charging mode at a second current until the voltage of the battery module reaches a preset upper limit value of the total voltage of the battery module, wherein the first current is greater than the second current.

[0231] In some embodiments, the module charge and discharge control module 601 is configured to charge the battery module to the preset upper limit value of the total voltage of the battery module at a preset cycle rate.

[0232] In some embodiments, the preset cycle rate includes one cycle rate.

[0233] In some embodiments, the preset cycle rate includes a plurality of cycle rates, and a sum of target charging capacities corresponding to each cycle rate is the charging capacity of the battery module.

[0234] In some embodiments, the plurality of cycle rates are step cycle rates.

[0235] The above-mentioned modules in the battery module cycle aging test device can be realized by software, hardware, and combinations thereof, in whole or in part. The above-mentioned modules can be embedded in or independent of the processor in the computer device in hardware form, or can be stored in the memory in the computer device in software form, so as to be called and executed by the processor to perform the operations corresponding to the above-mentioned modules.

[0236] In some embodiments, a battery module cycle aging test system is also provided. Referring to FIG. 7, the test system 20 includes a first charge and discharge device 201 and a second charge and discharge device 202. The first charge and discharge device 201 is configured to be connected to the input end and the output end of the battery module 10 to be tested. The second charge and discharge device 202 is configured to be connected to both ends of the battery cell in the battery module 10 to be tested.

[0237] The first charge and discharge device 201 is configured to perform a charging operation and / or a discharging operation on the battery module.

[0238] The second charge and discharge device 202 is configured to perform a discharging operation on the battery cell in the battery module.

[0239] The first charge-discharge device 201 can realize large-current charge-discharge operation, for example, can provide large-current charge-discharge operation of 50A-300A. The second charge-discharge device 202 can realize small-current charge-discharge operation, for example, can realize small-current discharge operation of 0.5A-10A.

[0240] The cycle aging test system of the battery module based on the embodiment can perform charge operation and / or discharge operation on the battery module through the first charge-discharge device, and can perform discharge operation on the battery cells in the battery module through the second charge-discharge device. Therefore, when the cycle aging test of the battery module is needed, the charge operation and the discharge operation of the battery module can be performed through the first charge-discharge device, so as to complete the cycle aging of the whole battery module, and then the discharge operation of the battery cells in the battery module can be performed based on the second charge-discharge device, so as to realize the accelerated aging of the battery cells of the battery module, thereby realizing the acceleration of the cycle aging test and realizing the cycle aging test of the battery module with short test time.

[0241] The specific form of the second charge-discharge device 202 is not limited, as long as it can realize the discharge operation of multiple or even all battery cells in the battery module. In some specific examples, the second charge-discharge device includes a plurality of charge-discharge units, one charge-discharge unit is connected to both ends of one battery cell in the battery module to be tested, so that the discharge operation of multiple battery cells in the battery module can be realized through one-to-one connection.

[0242] Taking the example of performing charge operation and discharge operation on the battery module through the first charge-discharge device 201, so as to complete the cycle aging of the whole battery module, and then performing discharge operation on the battery cells in the battery module based on the second charge-discharge device 202, so as to realize the accelerated aging of the battery cells of the battery module, after the first charge-discharge device 201 completes the cycle aging of the whole battery module, a signal can be sent to the second charge-discharge device 202, the second charge-discharge device 202 starts to perform discharge operation on the battery cells in the battery module, and after completing the discharge operation on the battery cells in the battery module, a signal is sent to the first charge-discharge device 201, the first charge-discharge device 201 starts to perform charge and discharge operation on the battery module, and the above process is repeated, so as to complete multiple rounds of cycle aging test on the battery module to be tested.

[0243] In some embodiments, referring to FIG. 8, the test system 20 can further include a control device 203 in communication connection with the first charge-discharge device 201 and the second charge-discharge device 202;

[0244] The control device 203 is configured to control the second charging and discharging device 202 to perform discharging operation on the battery cells in the battery module 10 after the first charging and discharging device 201 performs a round of charging operation and discharging operation on the battery module 10, and control the first charging and discharging device 201 to perform charging operation and discharging operation on the battery module 10 in sequence after the discharging operation on the battery cells is completed.

[0245] Based on the embodiment, the control device 203 can be used to realize the joint control of the first charging and discharging device and the second charging and discharging device, and the control device can be used to realize the centralized control of the cycle aging test.

[0246] In some embodiments, referring to FIG. 9, the test system 20 further includes a verification battery module 204, which is a battery module of the same type as the battery module 10, and at least one battery cell in the verification battery module 204 is replaced by a battery module in which a pressure sensor is arranged.

[0247] A top view of a partial structure of a specific example of the verification battery module 204 is shown in FIG. 10. In the example shown in FIG. 10, two battery cells are removed, and a pressure sensor 2041 is arranged at the positions of the removed battery cells to monitor the internal swelling force of the verification battery module 204. The control device 203 uses the swelling force measured by the pressure sensor 2041 as the internal swelling force of the battery module to be tested.

[0248] Referring to FIG. 10, in some embodiments, the verification battery module 204 further includes a clamping assembly, which includes a first clamping part 2042 and a second clamping part 2043, and the pressure sensor 2041 is arranged between the first clamping part 2042 and the second clamping part 2043. At least one battery cell in the verification battery module 204 is replaced by the clamping assembly and the pressure sensor. By arranging the clamping assembly and arranging the pressure sensor between the first clamping part 2042 and the second clamping part 2043, the fixation of the pressure sensor can be more facilitated, the situation of the pressure sensor shaking can be reduced, and the accuracy of the internal swelling force measured by the pressure sensor can be improved.

[0249] The thickness of the first clamping part 2042 and the second clamping part 2043 can be determined in combination with the thickness of the sensor and the thickness of the battery cell. The thickness direction refers to the arrangement direction between the battery cells. The thickness of the battery cell is denoted as a, the thickness of the pressure sensor is denoted as b, and it is assumed that the thickness of the first clamping part 2042 and the second clamping part 2043 is the same. Taking the case of taking out 4 battery cells as an example, without considering the gap between the battery cells, the thickness of the first clamping part 2042 and the second clamping part 2043 can be set to ((a*4)-b) / 2. It should be understood that, in the case of considering the gap between the battery cells, the formula ((a*4)-b) / 2 can be correspondingly adjusted.

[0250] The width and length of the first clamping part 2042 and the second clamping part 2043 can be consistent with the width and length of the battery cells in the battery module, so as to verify the overall grouping performance of the battery module.

[0251] In the above-mentioned cycle aging test system of the battery module, the specific charging and / or discharging mode of the first charging and discharging device and the second charging and discharging device can be similar to the implementation scheme described in the above-mentioned cycle aging test method of the battery module.

[0252] In one embodiment, a computer device, which can be a server, is provided, and an internal structure diagram of the computer device can be as shown in FIG. 11. The computer device includes a processor, a memory and a network interface connected through a system bus. The processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operating system and the computer program in the non-volatile storage medium to run. The database of the computer device is configured to store data related to the cycle aging test of the battery module, such as the above-mentioned preset acceleration rate, the preset acceleration potential, the monitored swelling force, and the like. The network interface of the computer device is configured to communicate with an external terminal through a network connection. The computer program is executed by the processor to implement a cycle aging test method of a battery module.

[0253] Those skilled in the art can understand that the structure shown in FIG. 11 is only a block diagram of part of the structure related to the scheme of the present application, and does not constitute a limitation on the computer device to which the scheme of the present application is applied. Specifically, the computer device can include more or fewer components than those shown in the figure, or combine certain components, or have a different component arrangement.

[0254] In one embodiment, a computer device is provided, comprising a memory and a processor, the memory having stored therein a computer program, the processor implementing the steps of the cycle aging test method of the battery module in any of the embodiments described above when executing the computer program.

[0255] In one embodiment, a computer readable storage medium is provided, having stored thereon a computer program, the computer program implementing the steps of the cycle aging test method of the battery module in any of the embodiments described above when executed by a processor.

[0256] In one embodiment, a computer program product is provided, comprising a computer program, the computer program implementing the steps of the cycle aging test method of the battery module in any of the embodiments described above when executed by a processor.

[0257] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer readable storage medium, and when the computer program is executed, the processes of the above-mentioned embodiments of the methods can be included. Any reference to memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (Read-Only Memory, ROM), magnetic tape, floppy disk, flash memory, optical storage, high-density embedded non-volatile memory, resistive memory (ReRAM), magnetoresistive memory (Magnetoresistive Random Access Memory, MRAM), ferroelectric memory (Ferroelectric Random Access Memory, FRAM), phase change memory (Phase Change Memory, PCM), graphene memory, etc. Volatile memory can include random access memory (Random Access Memory, RAM) or external cache memory, etc. As an illustration but not limitation, the RAM can be in various forms, such as static random access memory (Static Random Access Memory, SRAM) or dynamic random access memory (Dynamic Random Access Memory, DRAM), etc. The database involved in the embodiments provided in the present application can include at least one of a relational database and a non-relational database. The non-relational database can include a distributed database based on a block chain, etc., without being limited thereto. The processor involved in the embodiments provided in the present application can be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., without being limited thereto.

[0258] Any combination of the technical features of the above embodiments can be made. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

[0259] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of protection of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A cycle aging test method of a battery module, wherein, The method comprises, in a cycle aging test, performing the following steps: sequentially performing charging operation and discharging operation on the battery module; after the discharging operation on the battery module ends, performing discharging operation on the battery cells in the battery module individually.

2. The method of claim 1, wherein, The discharging operation on the battery cells in the battery module individually comprises: performing discharging operation on each battery cell in the battery module respectively to discharge each battery cell to a preset voltage.

3. The method of claim 2, wherein, The discharging operation on each battery cell in the battery module respectively to discharge each battery cell to a preset voltage comprises: performing discharging operation on each battery cell in the battery module respectively at a preset acceleration rate until each battery cell is discharged to a preset voltage.

4. The method of claim 3, wherein, The preset acceleration rate is 0.01C-0.1C.

5. The method of claim 4, wherein, The preset acceleration rate is 0.04C-0.05C.

6. The method according to any one of claims 2 to 5, wherein, The preset voltage is 0.5V-1.5V.

7. The method of claim 6, wherein, The preset voltage is 0.8V-1.0V.

8. The method according to any one of claims 1 to 5, wherein, The current for the discharging operation on the battery module is greater than the current for the discharging operation on the battery cells individually.

9. The method of claim 8, wherein, The current for the charging operation and / or the discharging operation on the battery module is greater than or equal to 50A and less than or equal to 500A, and the current for the discharging operation on the battery cells is greater than or equal to 0.5A and less than or equal to 10A.

10. The method according to any one of claims 1 to 5, wherein, The method further comprises, in the cycle aging test, monitoring the swelling force of the battery module.

11. The method of claim 10, wherein, The monitoring of the swelling force of the battery module comprises: performing the cycle aging test on a verification battery module synchronously, the verification battery module being a battery module of the same model as the battery module and having at least one battery cell replaced by a pressure sensor; obtaining the pressure detected by the pressure sensor as the swelling force of the battery module.

12. The method of any one of claims 1 to 11, wherein, The sequentially performing charging operation and discharging operation on the battery module comprises: performing charging operation on the battery module until the voltage of the battery module reaches an upper limit value of the total voltage of the battery module; after resting for a second time length, performing discharging operation on the battery module until the voltage of the battery module reaches a lower limit value of the total voltage of the battery module.

13. The method of claim 12, wherein, The performing charging operation on the battery module until the voltage of the battery module reaches an upper limit value of the total voltage of the battery module comprises: charging the battery module at a preset cycle rate to the upper limit value of the total voltage of the battery module.

14. The method of claim 13, wherein, The preset cycle rate comprises one cycle rate.

15. The method of claim 13, wherein, The preset cycle rate comprises a plurality of cycle rates, and the sum of the target charging capacities corresponding to each cycle rate is the charging capacity of the battery module.

16. The method of claim 15, wherein, The plurality of cycle rates are step cycle rates.

17. The method of any one of claims 12 to 16, wherein, The method further comprises: monitoring the total voltage value of the battery module and the voltage value of the battery cells; if the total voltage value of the battery module reaches the upper limit value of the total voltage of the battery module or the voltage value of any battery cell reaches the upper limit value of the voltage of the battery cell, determining that the voltage of the battery module reaches the upper limit value of the total voltage of the battery module.

18. The method of any one of claims 12 to 16, wherein, The method further comprises: monitoring the total voltage value of the battery module and the voltage value of the battery cells; If the total voltage value of the battery module reaches a lower limit value of the total voltage of the module, or the voltage value of any one battery cell reaches a lower limit value of the voltage of the battery cell, it is determined that the voltage of the battery module reaches the lower limit value of the total voltage of the module.

19. A cycle aging test apparatus of a battery module, wherein, The device comprises: The module charging and discharging control module is configured to sequentially perform charging and discharging operations on the battery module. The battery cell charging and discharging control module is configured to perform a discharging operation on the battery cells in the battery module after the module charging and discharging control module performs a charging operation and a discharging operation on the battery module.

20. A cycle aging test system for a battery module, wherein, The test system comprises a first charging and discharging device and a second charging and discharging device, the first charging and discharging device is configured to be connected to the input end and the output end of the battery module to be tested, and the second charging and discharging device is configured to be connected to both ends of the battery cells in the battery module to be tested. The first charging and discharging device is configured to perform a charging operation and / or a discharging operation on the battery module. The second charging and discharging device is configured to perform a discharging operation on the battery cells in the battery module.

21. The system of claim 20, wherein, The test system further comprises a control device in communication connection with the first charging and discharging device and the second charging and discharging device. The control device is configured to control the second charging and discharging device to perform a discharging operation on the battery cells in the battery module after the first charging and discharging device performs a charging operation and a discharging operation on the battery module, and control the first charging and discharging device to sequentially perform a charging operation and a discharging operation on the battery module after the discharging operation of the battery cells is completed.

22. The system of claim 20 or 21, wherein, The test system further comprises a verification battery module, which is a battery module of the same model as the battery module to be tested, and at least one battery cell in the verification battery module is replaced by a pressure sensor.

23. The system of claim 22, wherein, The verification battery module further comprises a clamping assembly, the clamping assembly comprises a first clamping part and a second clamping part, the pressure sensor is arranged between the first clamping part and the second clamping part, and at least one battery cell in the verification battery module is replaced by the clamping assembly and the pressure sensor.

24. The system of claim 20 or 21, wherein, The second charging and discharging device comprises a plurality of charging and discharging units, and one charging and discharging unit is connected to both ends of one battery cell in the battery module to be tested.

25. A computer device comprising a memory and a processor, the memory storing a computer program, wherein, The processor executes the computer program to realize the steps of the method of any one of claims 1-18.

26. A computer readable storage medium having stored thereon a computer program, wherein, The computer program is executed by the processor to realize the steps of the method of any one of claims 1-18.

27. A computer program product comprising a computer program, wherein, The computer program is executed by the processor to realize the steps of the method of any one of claims 1-18.

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