Battery module cycle aging test method, device and system

Abstract

The present application relates to a battery module cycle aging test method, device and system, and relates to the field of energy storage test technology; the method includes: in a cycle aging test, the battery module is charged and discharged in sequence; after the discharge operation of the battery module is completed, the battery cells in the battery module are discharged separately. The adoption of this solution can reduce the test time of cycle aging, and realize the cycle aging test of the battery module with a short test time.

Description

Technical Field

[0001] The present application relates to the field of energy storage testing technology, and in particular to a method, device, system, computer equipment, storage medium and computer program product for a cycle aging test of a battery module. Background Art

[0002] With the rapid development of the new energy industry, the energy density of batteries (such as lithium-ion batteries) is getting higher and higher, and extreme 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 battery failure in the later stage of use, resulting in serious safety hazards.

[0003] In order to improve safety, a systematic risk assessment is usually conducted during the R&D phase, which means that the single cells and battery modules need to be tested separately, such as cycle aging tests, to quickly reach the EOL (End-of-life) state. However, as the battery life is getting longer and longer, it will take at least two years to test to the EOL state, which is too long and is undoubtedly unacceptable during the development phase. Summary of the invention

[0004] Based on this, it is necessary to provide a cycle aging test method, device, system, computer equipment, storage medium and computer program product for a battery module with a short test time to address the above technical problems.

[0005] 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:

[0006] Performing charging and discharging operations on the battery module in sequence;

[0007] After the discharge operation of the battery module is completed, the battery cells in the battery module are individually discharged.

[0008] Based on the cycle aging test method of this embodiment, in each round of cycle aging test, after the battery module is charged and discharged in sequence, for the battery module after the discharge operation, the battery cells in the battery module are further discharged individually, so as to further discharge the battery cells in the battery module individually. By further discharging the battery cells in the battery module individually, accelerated aging of the battery cells is achieved, which helps to make the battery cells and the battery module reach the EOL state as soon as possible, so that on this basis, the test time of the cycle aging can be reduced, and the cycle aging test of the battery module with a short test time is achieved.

[0009] In some embodiments, the battery cells in the battery module are individually discharged, including:

[0010] The discharge operation is performed on each battery cell in the battery module to discharge each battery cell to a preset voltage.

[0011] Therefore, when the battery cells in the battery module are discharged individually, the discharge operation is performed on each battery cell in the battery module individually, that is, each battery cell in the battery module can be discharged individually, thereby achieving accelerated 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, so that the test time of the cycle aging can be further reduced on this basis.

[0012] In some embodiments, the discharging operation is performed on each battery cell in the battery module to discharge each battery cell to a preset voltage, including:

[0013] The battery cells in the battery module are respectively discharged at a preset acceleration rate until each battery cell is discharged to a preset voltage.

[0014] Based on this embodiment, when discharging each battery cell in the battery module, the discharge operation is performed with a current determined based on a preset acceleration rate of the battery cell capacity, so that the discharge operation is performed within a set range of the preset acceleration rate, which helps to improve safety while improving the accelerated aging effect.

[0015] In some embodiments, the preset acceleration rate includes 0.01C~0.1C.

[0016] Based on this embodiment, the discharge operation of each battery cell is performed using an acceleration rate within this range, which can have a good accelerated aging effect and a reasonable acceleration time, and can help improve the performance of the cycle aging test.

[0017] In some embodiments, the preset acceleration rate includes 0.04C~0.05C.

[0018] Based on this embodiment, discharging each battery cell using an acceleration rate within this range can balance the accelerated aging effect and the acceleration time to a certain extent, which can help to further improve the performance of the cycle aging test.

[0019] In some embodiments, the preset voltage includes 0.5V~1.5V.

[0020] Based on this embodiment, by discharging the battery cell to within the voltage range, the battery cell can be accelerated to age, which can have a better accelerated aging effect and help improve the performance of the cycle aging test.

[0021] In some embodiments, the preset voltage includes 0.8V~1.0V.

[0022] Based on this embodiment, by discharging the battery cell to within the voltage range, the battery cell can be accelerated to age, which can have a better accelerated aging effect and help to further improve the performance of the cycle aging test.

[0023] In some embodiments, the current for discharging the battery module is greater than the current for discharging a single battery cell.

[0024] Based on this embodiment, the battery module can be charged and discharged by a large current, and the battery cells in the battery module can be discharged individually by a small current. After the battery module is discharged by a large current, the battery cells in the battery module can be further discharged individually by a small current, thereby realizing accelerated circulation of the battery cells of the battery module, thereby realizing accelerated circulation of the battery module and accelerating aging of the battery module.

[0025] In some embodiments, the current for charging and / or discharging the battery module is greater than or equal to 50A (amperes) 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.

[0026] In some embodiments, the method further includes: monitoring the expansion force of the battery module during the cycle aging test.

[0027] Based on this embodiment, in the cycle aging test, the expansion force of the battery module is also monitored. Therefore, while the cycle aging performance of the battery module is tested, the failure risk of the battery module can be evaluated based on the obtained expansion force, thereby improving the accuracy and safety of the cycle aging test.

[0028] In some embodiments, monitoring the expansion force of the battery module includes:

[0029] Performing a cycle aging test on the verification battery module simultaneously, the verification battery module is a battery module of the same model as the battery module and a pressure sensor is placed in place of at least one battery cell in the battery module;

[0030] The pressure detected by the pressure sensor is used as the expansion force of the battery module.

[0031] Based on this embodiment, when monitoring the expansion force of the battery module, the internal expansion force of the battery module is monitored, so that the change of the internal expansion force of the battery module can be monitored, and when monitoring the internal expansion force, it is achieved by monitoring the internal expansion force of a verification battery module that has the same model as the battery module and replaces the position of at least one battery cell in the battery module with a pressure sensor, thereby realizing the detection of the internal expansion force of the battery module without changing the internal structure of the battery module.

[0032] In some embodiments, after the discharge operation on the battery module is completed and before the discharge operation on the battery cells in the battery module is performed individually, the method further includes: allowing the battery module to stand for a first period of time.

[0033] After the discharge operation of the battery module is completed, by leaving the battery module stationary for a first period of time, the discharge operation of the battery module can enable the battery module to gradually tend to a stable state after the discharge operation. After the battery module tends to a stable state, the discharge operation of the battery cell is accelerated, which can help improve the stability and reliability of the cycle aging test.

[0034] In some embodiments, charging and discharging the battery module in sequence include:

[0035] The battery module is charged until the voltage of the battery module reaches the upper limit of the total voltage of the module;

[0036] After standing still for a second period of time, the battery module is discharged until the voltage of the battery module reaches a lower limit of the total voltage of the module.

[0037] Based on this embodiment, when the battery module is charged and discharged in sequence, the battery module is charged until the voltage of the battery module reaches the upper limit of the total voltage of the module, and is discharged until the voltage of the battery module reaches the lower limit of the total voltage of the module, thereby achieving full charging and full discharging of the battery module and one charging cycle of the battery module. After charging until the voltage reaches the upper limit of the total voltage of the module, before the battery module is discharged, it is left to stand for a second period of time, so that the battery module can gradually tend to a stable state after the charging operation, and the battery module is discharged again after it tends to a stable state to accelerate the test, which can help improve the stability and reliability of the cycle aging test.

[0038] In some embodiments, charging the battery module until the voltage of the battery module reaches an upper limit of the total voltage of the module includes:

[0039] The battery module is charged through a constant current charging mode until the voltage of the battery module reaches the upper limit of the total voltage of the module.

[0040] In some embodiments, charging the battery module until the voltage of the battery module reaches an upper limit of the total voltage of the module includes:

[0041] The battery module is charged in constant voltage mode until the voltage of the battery module reaches the upper limit of the total voltage of the module.

[0042] In some embodiments, charging the battery module until the voltage of the battery module reaches an upper limit of the total voltage of the module includes:

[0043] The battery module is charged in a constant current charging mode until the voltage of the battery module reaches the upper limit of the total voltage of the module;

[0044] The battery module that reaches the upper limit of the total voltage of the module is charged through the constant voltage mode until the current of the battery module reaches the preset current value.

[0045] In some embodiments, charging the battery module until the voltage of the battery module reaches an upper limit of the total voltage of the module includes:

[0046] Charging the battery module with a first current in a constant current charging mode until the voltage of the battery module reaches a preset voltage upper limit value;

[0047] The battery module is charged with the second current in a constant current charging mode until the voltage of the battery module reaches an upper limit of the total voltage of the module, wherein the first current is greater than the second current.

[0048] In some embodiments, charging the battery module until the voltage of the battery module reaches an upper limit of the total voltage of the module includes:

[0049] The battery module is charged at a preset cycle rate to the upper limit of the total module voltage.

[0050] In some embodiments, the preset cycle rate includes a cycle rate.

[0051] In some embodiments, the preset cycle rate includes multiple cycle rates, and the sum of the target charging power corresponding to each cycle rate is the charging power of the battery module.

[0052] Among them, the multiple cycle ratios are step cycle ratios.

[0053] In a second aspect, the present application also provides a battery module cycle aging test device, wherein the device comprises:

[0054] The module charge and discharge control module is used to perform charging and discharging operations on the battery module in sequence;

[0055] The battery cell charging and discharging control module is used to perform a discharge operation on the battery cells in the battery module individually after the module charging and discharging control module performs a round of charging and discharging operations on the battery module.

[0056] In a third aspect, the present application also provides a cycle aging test system for a battery module, wherein the test system comprises a first charge-discharge device and a second charge-discharge device, the first charge-discharge device being used to connect to the input end and the output end of the battery module to be tested, and the second charge-discharge device being used to connect to both ends of the battery cell in the battery module to be tested;

[0057] A first charging and discharging device, used for charging and / or discharging the battery module;

[0058] The second charging and discharging device is used to discharge the battery cells in the battery module.

[0059] In some embodiments, the test system further includes a control device communicatively coupled to the first charge-discharge device and the second charge-discharge device;

[0060] The control device is used to control the second charge and discharge device to perform a discharge operation on the battery cells in the battery module after the first charge and discharge device performs a round of charging and discharging operations on the battery module, and after the discharge operation of the battery cells is completed, control the first charge and discharge device to perform charging and discharging operations on the battery module in sequence.

[0061] In some embodiments, the test system further includes verifying a battery module, wherein the verifying battery module is a battery module of the same model as the battery module and in which a pressure sensor is placed in place of at least one battery cell in the battery module.

[0062] In some embodiments, the verification battery module also includes a clamping assembly, the clamping assembly includes a first clamping portion and a second clamping portion, the pressure sensor is arranged between the first clamping portion and the second clamping portion, and the position of at least one battery cell in the verification battery module is replaced by placing the clamping assembly and the pressure sensor.

[0063] In some embodiments, the second charge-discharge device includes a plurality of charge-discharge units, and one charge-discharge unit is connected to both ends of a battery cell in the battery module to be tested.

[0064] In a fourth aspect, the present application further provides a computer device, which includes a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the method in any of the above embodiments when executing the computer program.

[0065] In a fifth aspect, the present application further provides a computer-readable storage medium, wherein a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the steps of the method in any of the above embodiments are implemented.

[0066] In a sixth aspect, the present application further provides a computer program product, which includes a computer program, and when the computer program is executed by a processor, the steps of the method of any of the above embodiments are implemented.

[0067] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0069] Figure 1 A schematic diagram of a flow chart of a cycle aging test method for a battery module in one embodiment;

[0070] Figure 2 A schematic diagram of a flow chart of a cycle aging test method for a battery module in another embodiment;

[0071] Figure 3 A schematic diagram of a flow chart of a cycle aging test method for a battery module in another embodiment;

[0072] Figure 4 A schematic diagram of a flow chart of a cycle aging test method for a battery module in another embodiment;

[0073] Figure 5 A schematic diagram of a process for monitoring the expansion force of a battery module in one embodiment;

[0074] Figure 6 A structural block diagram of a cycle aging test device for a battery module in one embodiment;

[0075] Figure 7 A structural block diagram of a cycle aging test system for a battery module in one embodiment;

[0076] Figure 8 A structural block diagram of a cycle aging test system for a battery module in another embodiment;

[0077] Fig. 9 A structural block diagram of a cycle aging test system for a battery module in another embodiment;

[0078] Fig.10A schematic diagram of a partial top view of a verification battery module in an embodiment;

[0079] Fig.11 FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0080] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is 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 are not used to limit the present application.

[0081] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0082] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0083] 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 clearly and specifically defined.

[0084] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0085] 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, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0086] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0087] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "connection" should be understood in a broad sense, for example, it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0088] At present, in order to conduct a systematic risk assessment of batteries, some assessment methods are to perform cycle aging tests on batteries so that the batteries can quickly reach the EOL state, that is, it is necessary to conduct actual tests on single cells and battery modules separately, such as performing cycle aging tests, so that they can quickly reach the EOL state. However, as the service life of batteries is getting longer and longer, it will take at least two years to actually measure to the EOL state. The testing time is too long, which is undoubtedly unacceptable in the development stage.

[0089] After research, it was found that the battery module includes multiple battery cells arranged in series and / or parallel. During the cycle aging test, after the battery module is discharged, there may still be a certain amount of power remaining in the battery cells in the battery module, and the status of each battery cell is not uniform, that is, the battery cells in the battery module may not be in the lowest power state. Therefore, it can be considered to further discharge the battery cells in the battery module separately after the battery module is discharged, so as to achieve accelerated aging of the battery cells in the battery module, thereby achieving accelerated aging of the battery module, thereby achieving shortened aging cycle test, and achieving a cycle aging test with short test time.

[0090] Accordingly, the embodiment of the present application provides a cycle aging test method for a battery module, which can be applied in an application environment where a cycle aging test is performed on a battery module. The cycle aging test method for a battery module provided in the embodiment of the present application can perform multiple rounds of cycle aging tests until the battery module or each cell of the battery module reaches the EOL state.

[0091] like Figure 1 As shown, the cycle aging test method of the battery module provided in the embodiment of the present application performs the following steps in one cycle aging test:

[0092] Step S101: performing charging and discharging operations on the battery module in sequence.

[0093] The charging operation refers to the process of storing electric energy in the battery module when the battery module is in a charging state. The discharging operation refers to the process of releasing electric energy from the battery module when the battery module is in a discharging state.

[0094] By sequentially performing charging and discharging operations on the battery module, a charge and discharge cycle of the battery module is achieved.

[0095] Step S102: After the discharge operation of the battery module is completed, the battery cells in the battery module are individually discharged.

[0096] Discharging a cell refers to the process of releasing the electrical energy in the cell. Discharging a cell individually in a battery module refers to discharging a single cell, and only one cell is discharged in one discharge process. It should be understood that if multiple cells in a battery module are discharged individually, the discharge processes of these multiple cells are carried out separately. For example, after the discharge operation of one cell is completed, the next cell can be discharged, or these cells can be discharged separately through different discharge devices at the same time.

[0097] After the charge and discharge operation of the battery module is completed, the battery module has completed a cycle of charge and discharge. However, after the discharge operation of the battery module is completed, the battery cells in the battery module may still have some residual electricity. Therefore, the battery cells in the battery module can be discharged separately again to release the residual electricity in the battery cells, thereby achieving accelerated aging of the battery cells and further achieving accelerated aging of the battery module.

[0098] Based on the cycle aging test method of this embodiment, during a round of cycle aging test, after the battery module is charged and discharged in sequence, for the battery module after the discharge operation, the battery cells in the battery module are further discharged individually, so as to further discharge the battery cells in the battery module individually. By further discharging the battery cells in the battery module individually, accelerated aging of the battery cells is achieved, which helps to make the battery cells and the battery module reach the EOL state as soon as possible, thereby reducing the test time of the cycle aging on this basis, and realizing the cycle aging test of the battery module with a short test time.

[0099] Among them, after the battery module is discharged, the status of each battery cell in the battery module is not uniform, and some of the battery cells may no longer have residual power, or all of the battery cells may have residual power. When the battery cells in the battery module are discharged separately, only some of the battery cells in the battery module can be discharged separately, wherein the partial battery cells to be discharged can be some of the battery cells with residual power, or all of the battery cells with residual power, or some of the battery cells randomly selected in the battery module. In the embodiment of the present application, all of the battery cells in the battery module can be discharged separately.

[0100] Accordingly, in some embodiments, reference Figure 2 As shown, the cells in the battery module are individually discharged, including:

[0101] Step S1020: performing a discharge operation on each battery cell in the battery module to discharge each battery cell to a preset voltage.

[0102] When discharging the battery cells, the voltage of each battery cell can be detected first. When the voltage of the battery cell is greater than the preset voltage, the battery cell can be discharged to discharge each battery cell to the preset voltage. The specific method of detecting the voltage of the battery cell is not limited. The device for charging and discharging the battery cell can be provided with a voltage detection component to detect the voltage of the battery cell.

[0103] The specific value of the preset voltage is not limited, and in some embodiments, it can be set based on the capacity voltage range of the battery cell.

[0104] Therefore, when the battery cells in the battery module are discharged individually, the discharge operation is performed on each battery cell in the battery module, that is, each battery cell in the battery module can be discharged individually, thereby achieving accelerated 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 time of the cycle aging on this basis.

[0105] When performing a discharge operation on each battery cell in the battery module, there is no limitation on the specific discharge operation method, and several of the methods are described below with examples.

[0106] In some embodiments, reference Figure 3 As shown, each battery cell in the battery module is discharged to a preset voltage, including:

[0107] Step S10211: performing a discharge operation on each battery cell in the battery module at a preset acceleration rate until each battery cell is discharged to a preset voltage.

[0108] The preset acceleration rate refers to a rate determined relative 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 may 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. Among them, the capacity of the battery module may be the rated capacity of the battery module or the design capacity of the battery module. In an embodiment of the present application, the capacity C of the battery module may also be the actual capacity of the battery module. For example, after the battery module is charged, during the process of discharging the battery module, the discharge capacity value may be tested, and the discharge capacity value may be used as the actual capacity of the battery module. In some embodiments, each time the discharge capacity value is tested, the preset acceleration rate may be adjusted, thereby reducing the possibility of lithium plating.

[0109] Taking the discharge capacity value passed the test as the capacity of the battery module as an example, the current for discharging the battery cell can be expressed as k*Cn, where n represents the number of times the discharge capacity value is tested, and Cn represents the capacity of the battery module obtained by the nth test.

[0110] 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 requirements. For example, the preset voltage in some specific examples can be set to 1.0V.

[0111] Based on this embodiment, when each battery cell in the battery module is discharged individually, the current is determined based on the preset acceleration rate of the capacity of the battery module, so that the discharge operation is performed within the set range of the preset acceleration rate, which helps to improve safety while improving the accelerated aging effect.

[0112] The specific range of the preset acceleration rate is not limited. After experimental testing, it is found that the lower the preset acceleration rate, the more obvious the accelerated aging effect, but the longer the accelerated aging time. The higher the preset acceleration rate, the worse the accelerated aging effect, but the shorter the accelerated aging time. After experimental testing, it is found that when the preset acceleration rate is between 0.01C and 0.1C, it can have a good accelerated aging effect, and the length of the accelerated aging time can be significantly shortened compared to the solution of not discharging the battery cell.

[0113] Based on this embodiment, each battery cell is discharged individually using an acceleration rate within this range, which can achieve a good accelerated aging effect and a reasonable acceleration time, and can help improve the performance of the cycle aging test.

[0114] After further research and testing, it was 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 duration of accelerated aging can be further shortened, achieving a certain balance between the effect of accelerated aging and the acceleration duration.

[0115] Based on this embodiment, discharging each battery cell using an acceleration rate within this range can balance the accelerated aging effect and the acceleration time to a certain extent, which can help to further improve the performance of the cycle aging test.

[0116] The specific range of the preset voltage is not limited. Generally speaking, the smaller the preset voltage value is, the better the accelerated aging effect is. However, if the preset voltage value is set too small, it will also cause serious overcharging. After research and testing, it was found that when the preset voltage is in the range of 0.5V~1.5V, it can have a better accelerated aging effect, which can help improve the performance of the cycle aging test. After further research and testing, it was found that when the preset voltage is in the range of 0.8V~1.0V, it can have a better accelerated aging effect, and the overcharge can also be within an acceptable range, which can help further improve the performance of the cycle aging test.

[0117] In some embodiments, the current for discharging the battery module is greater than the current for discharging a single battery cell.

[0118] A battery module is a module formed by connecting multiple battery cells in series and / or in parallel. Therefore, the battery module can be charged and discharged with a large current to quickly cycle the battery module, while the battery cells are discharged individually with a small current. This can accelerate the battery cells while maintaining the battery performance and perform cycle aging tests.

[0119] In some embodiments, the current for charging and / or discharging the battery module is greater than or equal to 50A and less than or equal to 500A, and the current for discharging a single battery cell is greater than or equal to 0.5A and less than or equal to 10A.

[0120] Based on this embodiment, the battery module can be charged and discharged by a large current, and the battery cells in the battery module can be discharged individually by a small current. After the battery module is discharged by a large current, the battery cells in the battery module can be further discharged individually by a small current, thereby realizing accelerated circulation of the battery cells of the battery module, thereby realizing accelerated circulation of the battery module and accelerating aging of the battery module.

[0121] In some embodiments, reference Figure 4 As shown, the method also includes:

[0122] Step S103: During the cycle aging test, the expansion force of the battery module is monitored.

[0123] Expansion force refers to the force exerted on the battery shell due to the gas generation and volume change of battery materials caused by the internal chemical reaction of the battery during the battery charging and discharging process. The expansion force of the battery has a certain impact on the performance and service life of the battery. If the expansion force is too high, it will cause excessive pressure on the battery shell, causing the battery shell to deform or even rupture, thereby affecting the performance and service life of the battery.

[0124] With the current trend of higher and higher energy density of batteries and extreme design (high group margin, thick coating design, etc.), the problem of increasing expansion force of batteries in the later stage of use comes along. Excessive expansion force will lead to the risk of failure of the structural frame (side panel structure, end panel structure, weld connection, etc.) of the lithium-ion battery module, resulting in serious safety hazards.

[0125] In the embodiment of the present application, by monitoring the expansion force of the battery module, the performance change of the battery module in the cycle aging test can be evaluated based on the monitored expansion force. It can also be used to evaluate the life of the battery module. The expansion force can be combined to determine whether the battery module has reached the EOL state. On this basis, the safety of the battery module during the cycle aging test can be confirmed and improved.

[0126] Based on this embodiment, in the cycle aging test, the expansion force of the battery module is also monitored. Therefore, while the cycle aging performance of the battery module is tested, the failure risk of the battery module can be evaluated based on the obtained expansion force, thereby improving the accuracy and safety of the cycle aging test.

[0127] The method of monitoring and obtaining the expansion force of the battery module is not limited. In some embodiments, a pressure sensor may be disposed on the outside of the battery module, and the pressure detected by the pressure sensor disposed on the outside is used as the expansion force of the battery module.

[0128] In other embodiments, the expansion force of the battery module can also be detected by measuring the expansion force of the battery cell inside the battery module. However, as a module that is set as a group, a pressure sensor is usually not specially set inside the battery module. If a pressure sensor is added inside the battery module to be tested after it has been produced, it is easy to affect the overall structure of the battery module.

[0129] Accordingly, in some embodiments, reference Figure 5 As shown, monitoring the expansion force of the battery module in step S103 may include:

[0130] Step S1031: synchronously performing a cycle aging test on the verification battery module, the verification battery module is a battery module of the same model as the battery module and a pressure sensor is placed in place of at least one battery cell in the battery module.

[0131] The verification battery module has the same model as the battery module to be tested, but at least one battery cell in the verification battery module is removed, and a pressure sensor is placed at the original position of the removed battery cell. The number of removed batteries can be determined based on the size of the pressure sensor.

[0132] Step S1032: The pressure detected by the pressure sensor is used as the expansion force of the battery module.

[0133] Generally speaking, the size of the pressure sensor will not be very large, so the number of removed battery cells will be relatively small. The battery module usually contains dozens or even hundreds of battery cells. By performing cycle aging tests on the battery module to be tested and the verification battery module simultaneously, the charge and discharge states of the battery module to be tested and the verification battery module are the same. 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 used as the expansion force of the battery module to be tested.

[0134] Based on this embodiment, when monitoring the expansion force of the battery module, the internal expansion force of the battery module is monitored, so that the change of the internal expansion force of the battery module can be monitored, and when monitoring the internal expansion force, it is achieved by monitoring the internal expansion force of a verification battery module that has the same model as the battery module and replaces the position of at least one battery cell in the battery module with a pressure sensor, thereby realizing the detection of the internal expansion force of the battery module without changing the internal structure of the battery module.

[0135] In some embodiments, after the discharge operation of the battery module in step S101 is completed, and before the individual discharge operation of the battery cells in the battery module in step S102 is performed, the method further includes: allowing the battery module to stand for a first period of time.

[0136] The specific duration of the first duration is not limited. In some embodiments, the first duration can be set to 10 minutes. It is understandable that in other embodiments, the first duration can also be set to other durations.

[0137] After the discharge operation of the battery module is completed, the battery module is allowed to stand for a first period of time so that the battery module gradually tends to a stable state after the discharge operation. After the battery module tends to a stable state, the discharge operation of the battery cell is accelerated, which can help improve the stability and reliability of the cycle aging test.

[0138] In some embodiments, charging and discharging the battery module in sequence include:

[0139] The battery module is charged until the voltage of the battery module reaches the upper limit of the total voltage of the module;

[0140] After standing still for a second period of time, the battery module is discharged until the voltage of the battery module reaches a lower limit of the total voltage of the module.

[0141] The upper limit of the total module voltage refers to the upper limit of the total voltage of the battery module. The upper limit of the total module voltage can be determined based on the number of cells contained in the battery module and the series-parallel relationship of the cells contained in the battery module. Taking the battery modules contained in the battery module as an example, the upper limit of the total module voltage of the battery module is N*Vmax, where N is the number of cells contained in the battery module, and Vmax is the upper limit of the voltage of each cell.

[0142] The lower limit of the total module voltage refers to the lower limit of the total voltage of the battery module. The lower limit of the total module voltage can be determined based on the number of cells contained in the battery module and the series-parallel relationship of the cells contained in the battery module. Taking the battery modules contained in the battery module as an example, the lower limit of the total module voltage of the battery module is N*Vmin, where N is the number of cells contained in the battery module, and Vmin is the lower limit of the voltage of each cell.

[0143] The specific duration of the second duration is not limited. In some embodiments, the second duration can be set to 30 minutes. It is understandable that in other embodiments, the second duration can also be set to other durations.

[0144] Based on this embodiment, when the battery module is charged and discharged in sequence, the battery module is charged until the voltage of the battery module reaches the upper limit of the total voltage of the module, and is discharged until the voltage of the battery module reaches the lower limit of the total voltage of the module, thereby achieving full charging and full discharging of the battery module and one charging cycle of the battery module. After charging until the voltage reaches the upper limit of the total voltage of the module, before the battery module is discharged, it is left to stand for a second period of time, so that the battery module can gradually tend to a stable state after the charging operation, and the battery module is discharged again after it tends to a stable state to accelerate the test, which can help improve the stability and reliability of the cycle aging test.

[0145] There is no limitation on the specific method of charging the battery module until the voltage of the battery module reaches the upper limit of the total voltage of the module. Some of the methods are described below with examples.

[0146] In some embodiments, charging the battery module until the voltage of the battery module reaches an upper limit of the total voltage of the module includes:

[0147] The battery module is charged through a constant current charging mode until the voltage of the battery module reaches the upper limit of the total voltage of the module.

[0148] The constant current charging mode (also called CC (Constant Current) mode) refers to a charging mode in which the current remains constant and the voltage gradually increases during the charging process. During the charging operation in the constant current charging mode, the current remains constant and the voltage gradually increases. The battery module is charged in the constant current charging mode, so that the battery module can be charged with a stable current.

[0149] In some embodiments, charging the battery module until the voltage of the battery module reaches an upper limit of the total voltage of the module includes:

[0150] The battery module is charged in constant voltage mode until the voltage of the battery module reaches the upper limit of the total voltage of the module.

[0151] The constant voltage mode (also called CV (Constant Voltage) mode) refers to a charging mode in which the voltage remains constant during the charging process. During the charging operation in the constant voltage mode, the voltage remains constant and the current gradually decreases. During the discharge operation in the constant voltage mode, the current decreases first and then increases. By charging the battery module in the constant voltage mode, the battery module can be charged with a stable voltage.

[0152] In some embodiments, charging the battery module until the voltage of the battery module reaches an upper limit of the total voltage of the module includes:

[0153] The battery module is charged in a constant current charging mode until the voltage of the battery module reaches the upper limit of the total voltage of the module;

[0154] The battery module that reaches the upper limit of the total voltage of the module is charged through the constant voltage mode until the current of the battery module reaches the preset current value.

[0155] The voltage of the battery module reaches the upper limit of the total voltage of the module, which means that the voltage of the battery module increases to be greater than or equal to the upper limit of the total voltage of the module. The current of the battery module reaches the preset current value, which means that the current of the battery module decreases to be less than or equal to the preset current value.

[0156] Based on this embodiment, when charging the battery module, the constant current charging mode and the constant voltage charging mode are combined to charge the battery module, so that the current is kept constant during the charging process, and when the voltage is charged to the upper limit voltage, the voltage is kept constant, and finally the current is gradually reduced to the preset current value before charging ends. Since the actual voltage of the battery module usually drops to a certain extent after charging the battery module through the constant current charging mode, further charging the battery module in combination with the constant voltage charging mode can achieve full charging of the battery module, and can further promote the acceleration of the aging cycle on this basis.

[0157] In some embodiments, charging the battery module until the voltage of the battery module reaches an upper limit of the total voltage of the module includes:

[0158] Charging the battery module with a first current in a constant current charging mode until the voltage of the battery module reaches a preset voltage upper limit value;

[0159] The battery module is charged with the second current in a constant current charging mode until the voltage of the battery module reaches an upper limit of the total voltage of the module, wherein the first current is greater than the second current.

[0160] 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 further slowly charged with a small current. For example, in some embodiments, the first current can be set to 1.0C and the second current can be set to 0.33C.

[0161] Based on this embodiment, when the battery module is charged, the battery module is first charged with a large first current through a constant current charging mode, so that the battery module can be charged quickly, and the battery module is further charged with a small second current, which can reduce the degree of voltage drop of the battery module after charging is completed, and can help improve the charging performance.

[0162] In some embodiments, charging the battery module until the voltage of the battery module reaches an upper limit of the total voltage of the module includes:

[0163] The battery module is charged at a preset cycle rate to the upper limit of the total module voltage.

[0164] The preset cycle rate is a rate determined relative to the capacity of the battery module. 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 capacitance of the battery module. For example, if the capacity of the battery module is C and the preset cycle rate is j, the current for charging the battery module is j*C.

[0165] There is no limitation on the setting method of the preset cycle rate. Taking charging the battery module in a constant current charging mode as an example, the preset cycle rate in some embodiments may be 0.33C~3.0C.

[0166] The preset cycle multiplier may be only one or may include more than two. For example, the preset cycle multiplier includes one cycle multiplier, and the preset cycle multiplier in a specific example may be set to 1.0C.

[0167] In some embodiments, the preset cycle rate includes multiple cycle rates, and the sum of the target charging power corresponding to each cycle rate is the charging power of the battery module. That is, after charging to its corresponding target charging power through each cycle rate, switch to charging at the next cycle rate. Taking 3 cycle rates as an example, the battery module can be charged through the first cycle rate, but the power of the battery module reaches K%. Then switch to charging the battery module through the second cycle rate until the power of the battery module reaches (K+L)%, that is, charge L% of the power through the second cycle rate. Then switch to charging through the third cycle rate until the power of the battery module reaches 100%, that is, charge (100-KL)% of the power through the third cycle rate.

[0168] Wherein, in the case where multiple cycle rates are provided, the manner of the multiple cycle rates is not limited. In some embodiments, the multiple cycle rates may be step cycle rates. For example, the multiple cycle rates in some embodiments may include 3.0C, 2.0C, 1.5C and 1.0C. The target charge power corresponding to each cycle rate, for example, the target charge power corresponding to the cycle rates 3.0C, 2.0C, 1.5C and 1.0C in some specific examples may be 10%, 10%, 10% and 70% respectively.

[0169] In the process of charging the battery module, there is no limitation on the method of determining whether the voltage of the battery module reaches the upper limit value of the total voltage of the module.

[0170] In some embodiments, the total voltage of the battery module can be measured, and when the total voltage of the battery module reaches the upper limit of the total voltage of the module (for example, N*Vmax), it can be determined that the voltage of the battery module has reached the upper limit of the total voltage of the module.

[0171] However, in the actual cycle process, due to the consistency differences between the battery cells, if only the total voltage is used for cutoff, safety problems such as overcharging and over-discharging of the battery cells may easily occur.

[0172] Therefore, in other embodiments, the voltage values ​​of all single cells can be monitored through a low-voltage wiring harness. When the voltage value of any single cell reaches the upper limit value Vmax, it can be determined that the voltage of the battery module has reached the upper limit value of the total voltage of the module.

[0173] In other embodiments, the total voltage value of the battery module and the voltage value of each single cell can be detected at the same time. When the total voltage value of the battery module reaches the upper limit value of the total voltage of the module, or the voltage value of any single cell reaches the upper limit value Vmax, that is, as long as any one of these two conditions is met, it can be determined that the total voltage value of the battery module reaches the upper limit value of the total voltage of the module.

[0174] Therefore, by combining the voltage value of the battery cell to determine whether the voltage of the battery module has reached the upper limit of the total voltage of the module, the problem of overcharging of the battery cell caused by charging operation based only on the total voltage of the battery module can be reduced.

[0175] There is no limitation on the specific method of discharging the battery module until the voltage of the battery module reaches the lower limit of the total voltage of the module. Some of the methods are described below with examples.

[0176] In some embodiments, the battery module is discharged until the voltage of the battery module reaches the lower limit of the total voltage of the module, including:

[0177] The battery module is discharged through the constant current discharge mode (also called DC mode) until the voltage of the battery module reaches the lower limit of the total voltage of the module. During the discharge operation through the constant current discharge mode, the current remains unchanged and the voltage gradually decreases. The battery module is discharged through the constant current discharge mode, so that the battery module can be discharged with a stable current.

[0178] When constant current discharge is performed, the specific discharge rate is not limited, and the rate in some embodiments may be 0.33C to 3.0C. In a specific example, constant current discharge may be performed at a rate of 0.1C.

[0179] In the process of discharging the battery module, there is no limitation on the method of determining whether the voltage of the battery module reaches the lower limit of the total voltage of the module.

[0180] In some embodiments, the total voltage of the battery module may be measured, and when the total voltage of the battery module reaches the lower limit of the total voltage of the module (eg, N*Vmin), it may be determined that the voltage of the battery module has reached the lower limit of the total voltage of the module.

[0181] However, in the actual cycle process, due to the consistency differences between the battery cells, if only the total voltage is used for cutoff, safety problems such as overcharging and over-discharging of the battery cells may easily occur.

[0182] Therefore, in other embodiments, the voltage values ​​of all single cells can be monitored through a low-voltage wiring harness. When the voltage value of any single cell reaches the lower limit value Vmin, it can be determined that the voltage of the battery module has reached the lower limit value of the total module voltage.

[0183] In other embodiments, the total voltage value of the battery module and the voltage value of each single cell can be detected at the same time. 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 cell reaches the lower limit value Vmin, that is, as long as any one of these 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.

[0184] Therefore, judging whether the voltage of the battery module has reached the lower limit of the total voltage of the module in combination with the voltage value of the battery cell can reduce the problem of over-discharge of the battery cell caused by cutting off the discharge operation based only on the total voltage of the battery module.

[0185] In some embodiments, the above method may further include: when a preset number of cycle aging tests is reached, performing a capacity test on the battery module, that is, testing the battery module capacity of the battery module.

[0186] The specific value of the preset rounds is not limited, for example, it can be 0 times (ie before the test), the 50th time, the 100th time, etc., but is not limited thereto and can be determined in combination with actual test requirements.

[0187] In one embodiment, the method of testing the capacity of the battery module may include: testing the battery module capacity of the battery module by charging and discharging the battery module, so that the battery capacity of the battery module can be obtained by the discharge capacity of the battery module after charging.

[0188] In some embodiments, charging and discharging the battery module to test the battery module capacity of the battery module includes:

[0189] The battery module is charged until the voltage of the battery module reaches the upper limit of the total voltage of the module;

[0190] After standing for a first predetermined time, discharging the battery module until the voltage of the battery module reaches a lower limit of the total voltage of the module;

[0191] The battery module capacity of the battery module is obtained based on the discharge quantity of the battery module during the discharge operation.

[0192] Based on this embodiment, when testing the battery module capacity of the battery module, the battery module is charged until the voltage of the battery module reaches the upper limit of the total voltage of the module, and then the battery module is discharged until the voltage of the battery module reaches the lower limit of the total voltage of the module. The battery module capacity of the battery module is obtained by fully charging and discharging the battery module and combining the discharge power of the discharge operation, so that the measured battery module capacity is the actual capacity of the battery module, which can improve the accuracy of the measured battery module capacity. After charging until the voltage reaches the upper limit of the total voltage of the module, before discharging the battery module, it is also allowed to stand for a first predetermined time, which can allow the battery module to gradually tend to a stable state after the charging operation. After the battery module tends to a stable state, the battery module is discharged again, and the battery module capacity is tested accordingly, which can further help to improve the accuracy of the measured battery module capacity.

[0193] The method of charging the battery module until the voltage of the battery module reaches the upper limit of the total voltage of the module may be the same as the above-mentioned charging operation, which will not be described in detail here.

[0194] It should be understood that after the cyclic aging test has started, when the preset number of cyclic aging tests is reached, or when the battery module is charged to the upper limit of the total voltage of the module and the battery module is discharged during the cyclic aging test, the battery module capacity of the battery module is measured.

[0195] In some embodiments, after the battery module capacity of the battery module is measured, the preset acceleration ratio can be adjusted simultaneously in combination with the measured battery module capacity, and the specific adjustment method is not limited.

[0196] Based on the embodiments described above, some specific examples are used for illustration below. When it is necessary to perform a cycle aging test on the battery module to be tested, first obtain a battery module of the same model as the battery module to be tested, and take out at least one battery cell in the middle of the battery module, and place a pressure sensor at the position where the battery cell is removed, so as to obtain a verification battery module. In the case where there is a gap between the pressure sensor and the adjacent battery cell or the gap is greater than a preset threshold, a clamping assembly may also be provided to fix the pressure sensor. Subsequently, the battery module to be tested and the verification battery module may be connected to the charging and discharging system, and the cycle aging test may be performed simultaneously. During the cycle aging test, the expansion force measured by the pressure sensor in the verification battery module may be used as the expansion force of the battery module to be tested.

[0197] When the battery module is subjected to a cycle aging test, the battery module to be tested and the verification battery module are tested simultaneously. 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 for the verification battery module is used as the expansion force of the battery module to be tested. During the cycle aging test, the expansion force obtained by monitoring 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.

[0198] When performing a cycle aging test on a battery module, multiple rounds of cycle testing processes may be performed. In a specific example, one round of cycle aging testing process may be performed as follows.

[0199] First, an aging cycle process of the battery module is performed. The process in a specific example can be as follows.

[0200] First, let it stand for a certain period of time, such as 30 minutes, and then charge the battery module until the voltage of the battery module reaches the upper limit of the total voltage of the module; taking the battery module in a series mode as an example, the upper limit of the total voltage of the module is Vmax*N. Then, let it stand for a second period of time, such as 30 minutes, and then discharge the battery module until the voltage of the battery module reaches the lower limit of the total voltage of the module; taking the battery module in a series mode as an example, the lower limit of the total voltage of the module is Vmin*N. Then let it stand for a first period of time, such as 10 minutes.

[0201] Secondly, after the aging cycle of the battery module is completed, the battery cells in the battery module are accelerated, for example, each battery cell in the battery module is discharged individually until the voltage of each battery cell reaches a preset voltage, for example, 1.0V.

[0202] The above-mentioned cycle aging test process is repeated for each round until a preset number of cycles is reached or the battery module reaches the EOL state.

[0203] It should be understood that during the above-mentioned cycle aging test, when the battery cells in the battery module are discharged for accelerated aging, the temperature of accelerated aging can be set to further enhance the accelerated effect of cycle aging. In some embodiments, the ambient temperature of the cycle aging test can be set to 35~45℃ (degrees Celsius), denoted as T, so that the acceleration effect of high temperature can be achieved. Since the battery module will also generate heat during the charging and discharging process, the temperature will also rise to a certain extent, so a cooling device can be configured at the same time. When the ambient temperature is greater than the T preset value (such as 5℃), the cooling device is turned on to cool the battery module and reduce the safety impact of excessive temperature. When the ambient temperature is lower than the T preset value (such as 5℃), the cooling device is turned off to maintain the battery module in a high temperature environment to achieve the acceleration effect of high temperature.

[0204] It should be understood that when a capacity test is required, in order to improve the accuracy of the capacity test, the test environment temperature can be set to a normal ambient temperature, such as 25° C. or a range thereof, but is not limited thereto.

[0205] Through the cycle aging test method of the battery module of the embodiment of the present application, an accelerated cycle aging test of the battery module can be achieved. Through actual testing, it is found that by combining the discharge of the battery cells in the battery module for accelerated aging, the time of the cycle aging test can be greatly shortened. After testing, it is found that the time required for the cycle aging of the battery module to the EOL state can be shortened from the traditional more than two years to less than 3 months. Moreover, by discharging the battery cells in the battery module separately to accelerate the cycle aging, all the single cells 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 cells is also reduced. And through actual testing, it is found that the cycle aging test method of the embodiment of the present application can achieve accelerated aging of the module capacity and expansion force of the battery module, and the growth trend of the expansion force is consistent with the growth trend of the normal cycle.

[0206] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0207] Based on the same inventive concept, the embodiment of the present application also provides a battery module cycle aging test device for implementing the battery module cycle aging test method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in the embodiments of the battery module cycle aging test device provided below can refer to the limitations of the battery module cycle aging test method above, and will not be repeated here.

[0208] In one embodiment, Figure 6 As shown, a cycle aging test device for a battery module is provided, the device includes a module charge and discharge control module 601 and a battery cell charge and discharge control module 602, wherein:

[0209] The module charge and discharge control module 601 is used to perform charging and discharging operations on the battery module in sequence;

[0210] The battery cell charging and discharging control module 602 is used to perform a discharge operation on the battery cells in the battery module individually after the module charging and discharging control module performs a round of charging and discharging operations on the battery module.

[0211] In some embodiments, the battery cell charge and discharge control module 602 is used to perform a discharge operation on each battery cell in the battery module to discharge each battery cell to a preset voltage.

[0212] In some embodiments, the battery cell charge and discharge control module 602 is used to perform discharge operations on each battery cell in the battery module at a preset acceleration rate until the power of each battery cell is discharged to a preset voltage.

[0213] In some embodiments, the preset acceleration rate includes 0.01C~0.1C.

[0214] In some embodiments, the preset acceleration rate includes 0.04C~0.05C.

[0215] In some embodiments, the preset voltage includes 0.5V~1.5V.

[0216] In some embodiments, the preset voltage includes 0.8V~1.0V.

[0217] In some embodiments, the current used by the module charge and discharge control module 601 to discharge the battery module is greater than the current used by the battery cell charge and discharge control module 602 to discharge a single battery cell.

[0218] In some embodiments, the module charge and discharge control module 601 charges and / or discharges the battery module with a current greater than or equal to 50A and less than or equal to 500A, and the battery cell charge and discharge control module 602 discharges the battery cell with a current greater than or equal to 0.5A and less than or equal to 10A.

[0219] In some embodiments, the apparatus further comprises:

[0220] The expansion force monitoring module is used to monitor the expansion force of the battery module during the cycle aging test.

[0221] In some embodiments, the apparatus simultaneously performs a cycle aging test on a verification battery module, the verification battery module being a battery module of the same model as the battery module and having a pressure sensor placed in place of at least one cell in the battery module;

[0222] The expansion force monitoring module uses the pressure detected by the pressure sensor as the expansion force of the battery module.

[0223] In some embodiments, after the discharge operation on the battery module is completed, the module charge and discharge control module 601 allows the battery module to stand for a first period of time.

[0224] In some embodiments, the module charge and discharge control module 601 is used to charge the battery module until the voltage of the battery module reaches the upper limit of the total voltage of the module; after standing for a second period of time, the battery module is discharged until the voltage of the battery module reaches the lower limit of the total voltage of the module.

[0225] In some embodiments, the module charge and discharge control module 601 is used to charge the battery module in a constant current charging mode until the voltage of the battery module reaches an upper limit value of the total voltage of the module.

[0226] In some embodiments, the module charge and discharge control module 601 is used to charge the battery module in a constant voltage mode until the voltage of the battery module reaches an upper limit value of the total voltage of the module.

[0227] In some embodiments, the module charging and discharging control module 601 is used to charge the battery module through a constant current charging mode until the voltage of the battery module reaches the upper limit of the total voltage of the module; and to charge the battery module that reaches the upper limit of the total voltage of the module through a constant voltage mode until the current of the battery module reaches a preset current value.

[0228] In some embodiments, the module charging and discharging control module 601 is used to charge the battery module with a first current through a constant current charging mode until the voltage of the battery module reaches a preset voltage upper limit; and charge the battery module with a second current through a constant current charging mode until the voltage of the battery module reaches a total module voltage upper limit, wherein the first current is greater than the second current.

[0229] In some embodiments, the module charge and discharge control module 601 is used to charge the battery module to an upper limit value of the total voltage of the module at a preset cycle rate.

[0230] In some embodiments, the preset cycle rate includes a cycle rate;

[0231] In some embodiments, the preset cycle rate includes multiple cycle rates, and the sum of the target charging power corresponding to each cycle rate is the charging power of the battery module.

[0232] In some embodiments, the plurality of cycling ratios are stepped cycling ratios.

[0233] Each module in the above-mentioned battery module cycle aging test device can be implemented in whole or in part by software, hardware and a combination thereof. Each of the above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the corresponding operations of each of the above modules.

[0234] In some embodiments, a battery module cycle aging test system is also provided, referring to Figure 7 As shown, the test system 20 includes a first charge-discharge device 201 and a second charge-discharge device 202, the first charge-discharge device 201 is used to connect to the input end and the output end of the battery module 10 to be tested, and the second charge-discharge device 202 is used to connect to the two ends of the battery cell in the battery module 10 to be tested;

[0235] The first charging and discharging device 201 is used to charge and / or discharge the battery module;

[0236] The second charging and discharging device 202 is used to discharge the battery cells in the battery module.

[0237] The first charge-discharge device 201 can realize high-current charge-discharge operation, for example, can provide high-current charge-discharge operation of 50A to 300A. The second charge-discharge device 202 can realize low-current charge-discharge operation, for example, can realize low-current discharge operation of 0.5A to 10A.

[0238] Based on the cycle aging test system of the battery module of this embodiment, the battery module can be charged and / or discharged by the first charge and discharge device, and the battery cells in the battery module can be discharged by the second charge and discharge device. Therefore, when the battery module needs to be subjected to a cycle aging test, the battery module can be charged and discharged by the first charge and discharge device, thereby completing the cycle aging of the battery module as a whole, and then the battery cells in the battery module can be discharged based on the second charge and discharge device to achieve accelerated aging of the battery cells in the battery module, thereby achieving acceleration of the cycle aging test and achieving a cycle aging test of the battery module with a short test time.

[0239] 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 cells in the battery module. In some specific examples, the second charge-discharge device includes multiple charge-discharge units, and one charge-discharge unit is connected to both ends of a cell in the battery module to be tested, so that the discharge operation of multiple cells in the battery module can be realized in a one-to-one connection manner.

[0240] Taking the example of charging and discharging the battery module through the first charging and discharging device to complete the cycle aging of the entire battery module, and then discharging the battery cells in the battery module based on the second charging and discharging device to achieve accelerated aging of the battery cells in the battery module, after the first charging and discharging device completes the cycle aging of the entire battery module, a signal can be sent to the second charging and discharging device, and the second charging and discharging device starts to discharge the battery cells in the battery module. After completing the discharge operation on the battery cells in the battery module, a signal is sent to the first charging and discharging device, and the first charging and discharging device starts to charge and discharge the battery module, and the above process is repeated to complete multiple rounds of cycle aging tests on the battery module to be tested.

[0241] In some embodiments, reference Figure 8 As shown, the test system 20 may further include a control device 203 that is communicatively connected to the first charge-discharge device 201 and the second charge-discharge device 202;

[0242] The control device 203 is used to control the second charge and discharge device 202 to perform a discharge operation on the battery cell 10 in the battery module 10 after the first charge and discharge device 201 performs a round of charging and discharging operations on the battery module 10, and after the discharge operation of the battery cell is completed, control the first charge and discharge device 201 to perform charging operations and discharging operations on the battery module 10 in sequence.

[0243] Based on this embodiment, the first charging and discharging device and the second charging and discharging device can be jointly controlled by the control device 203, and the cycle aging test can be centrally controlled by the control device.

[0244] In some embodiments, reference Fig. 9 As shown, the test system 20 also includes a verification battery module 204, which is a battery module of the same model as the battery module 10 and in which a pressure sensor is placed in place of at least one battery cell in the battery module.

[0245] A top view schematic diagram of a partial structure of a verification battery module 204 of a specific example is shown in FIG. Fig.10 shown. Fig.10 In the figure, two cells are taken out as an example for illustration. After the two cells are taken out, a pressure sensor 2041 is placed at the original position of the two cells, and the internal expansion force of the verification battery module 204 is monitored by the pressure sensor 2041. The control device 203 uses the expansion force measured by the pressure sensor 2041 as the internal expansion force of the battery module to be tested.

[0246] Also refer to Fig.10 As shown, in some embodiments, the verification battery module 204 further includes a clamping assembly, the clamping assembly includes a first clamping portion 2042 and a second clamping portion 2043, the pressure sensor 2041 is disposed between the first clamping portion 2042 and the second clamping portion 2043, and the clamping assembly and the pressure sensor are replaced in the position of at least one battery cell in the verification battery module 204. By providing the clamping assembly and arranging the pressure sensor between the first clamping portion 2042 and the second clamping portion 2043, it is more conducive to fixing the pressure sensor, reducing the shaking of the pressure sensor, and also helping to improve the accuracy of the internal expansion force measured by the pressure sensor.

[0247] 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. Let the thickness of the battery cell be a, and the thickness of the pressure sensor be b. Assuming that the thickness of the first clamping part 2042 and the second clamping part 2043 are the same, taking 4 battery cells as an example, without considering the gaps 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 gaps between the battery cells, the formula can be adaptively adjusted accordingly.

[0248] The width and length of the first clamping portion 2042 and the second clamping portion 2043 may be consistent with the width and length of the battery cells in the battery module to verify the overall grouping performance of the battery module.

[0249] In the cycle aging test system of the battery module, the specific charging and / or discharging method of the first charging and discharging device and the second charging and discharging device may be similar to the implementation scheme described in the cycle aging test method of the battery module.

[0250] In one embodiment, a computer device is provided. The computer device may be a server, and its internal structure diagram may be as follows: Fig.11 As shown. The computer device includes a processor, a memory and a network interface connected via a system bus. Among them, the processor of the computer device is used 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 operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store data related to the cycle aging test of the battery module, such as the above-mentioned preset acceleration rate, preset acceleration potential, monitored expansion force, etc. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a cycle aging test method for a battery module is implemented.

[0251] Those skilled in the art will understand that Fig.11 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0252] In one embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the steps of the cycle aging test method for the battery module in any of the embodiments described above are implemented.

[0253] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the cycle aging test method for a battery module in any of the embodiments described above are implemented.

[0254] In one embodiment, a computer program product is provided, including a computer program, which, when executed by a processor, implements the steps of the cycle aging test method for a battery module in any of the embodiments described above.

[0255] 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, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0256] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0257] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A battery module cycle aging test method, comprising performing multiple cycles of aging tests, wherein: In one round of the cyclic aging test, the following steps are performed: Performing charging and discharging operations on the battery module in sequence; After the discharge operation of the battery module is completed, the battery cells in the battery module are individually discharged; The charging and discharging operations are performed on the battery module in sequence, including: Charging the battery module until the voltage of the battery module reaches an upper limit of the total voltage of the module; After standing for a second period of time, the battery module is discharged until the voltage of the battery module reaches a lower limit of the total voltage of the module; Wherein, 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 one of the battery cells reaches the lower limit value of the voltage of the battery cell, it is determined that the total voltage value of the battery module reaches the lower limit value of the total voltage of the module.

2. The method according to claim 1, characterized in that The individual discharge operation of the battery cells in the battery module includes: The battery cells in the battery module are respectively discharged to a preset voltage.

3. The method according to claim 2, characterized in that The discharging operation is performed on each battery cell in the battery module to discharge each battery cell to a preset voltage, including: The battery cells in the battery module are respectively discharged at a preset acceleration rate until each battery cell is discharged to a preset voltage.

4. The method according to claim 3, characterized in that The preset acceleration ratio is 0.01C~0.1C.

5. The method according to claim 4, characterized in that The preset acceleration ratio is 0.04°C to 0.05°C.

6. The method according to any one of claims 2 to 5, characterized in that: The preset voltage is 0.5V~1.5V.

7. The method according to claim 6, characterized in that The preset voltage is 0.8 V ~1.0 V.

8. The method according to any one of claims 1 to 5, characterized in that: The current for discharging the battery module is greater than the current for discharging the battery cell individually.

9. The method according to claim 8, characterized in that The current for charging and / or discharging the battery module is greater than or equal to 50A 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.

10. The method according to any one of claims 1 to 5, characterized in that the method further comprises: In the cyclic aging test, the expansion force of the battery module is monitored.

11. The method according to claim 10, characterized in that The monitoring of the expansion force of the battery module comprises: The cycle aging test is simultaneously performed on a verification battery module, wherein the verification battery module is a battery module of the same model as the battery module and a pressure sensor is placed in place of at least one battery cell in the battery module; The pressure detected by the pressure sensor is used as the expansion force of the battery module.

12. A cycle aging test device for a battery module, wherein: The cyclic aging test device performs multiple rounds of cyclic aging tests, and the device comprises: A module charge and discharge control module, used to sequentially perform charging and discharging operations on the battery module; A battery cell charging and discharging control module, used to perform a discharge operation on the battery cells in the battery module individually after the module charging and discharging control module performs a round of charging and discharging operations on the battery module; The module charge and discharge control module is used to charge the battery module until the voltage of the battery module reaches the upper limit of the total voltage of the module; after standing for a second period of time, the battery module is discharged until the voltage of the battery module reaches the lower limit of the total voltage of the module, wherein when the total voltage value of the battery module reaches the lower limit of the total voltage of the module, or the voltage value of any one of the battery cells reaches the lower limit of the voltage of the battery cell, it is determined that the total voltage value of the battery module reaches the lower limit of the total voltage of the module.

13. 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, wherein the first charging and discharging device is used 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 used to be connected to the two ends of the battery cell in the battery module to be tested; The first charging and discharging device is used to perform charging and / or discharging operations on the battery module; The second charging and discharging device is used to discharge the battery cells in the battery module; Among them, the first charging and discharging device is used to charge the battery module until the voltage of the battery module reaches the upper limit value of the total voltage of the module; after standing for a second period of time, the battery module is discharged until the voltage of the battery module reaches the lower limit value of the total voltage of the module, wherein 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 one of the battery cells reaches the lower limit value of the voltage of the battery cell, it is determined that the total voltage value of the battery module reaches the lower limit value of the total voltage of the module.

14. The system according to claim 13, characterized in that The test system further includes a control device in communication connection with the first charge-discharge device and the second charge-discharge device; The control device is used to control the second charge and discharge device to perform a discharge operation on the battery cells in the battery module after the first charge and discharge device performs a round of charging and discharging operations on the battery module, and after the discharge operation of the battery cells is completed, control the first charge and discharge device to perform charging and discharging operations on the battery module in sequence.

15. The system according to claim 13 or 14, characterized in that The test system further comprises a verification battery module, which is a battery module of the same model as the battery module and in which a pressure sensor is placed in place of at least one battery cell in the battery module.

16. The system according to claim 15, characterized in that The verification battery module also includes a clamping assembly, which includes a first clamping portion and a second clamping portion, and the pressure sensor is arranged between the first clamping portion and the second clamping portion. The position of at least one battery cell in the verification battery module replaces the clamping assembly and the pressure sensor.

17. The system according to claim 13 or 14, characterized in that The second charge and discharge device includes a plurality of charge and discharge units, and one of the charge and discharge units is connected to two ends of a battery cell in the battery module to be tested.

18. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 11 are implemented.

19. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 11 are implemented.

20. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 11 are implemented.

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