Battery cell characteristic analysis method and device, storage medium and electronic device

Abstract

The application provides a battery cell characteristic analysis method and device, a storage medium and an electronic device. The electronic device obtains charging expansion force data and discharging expansion force data of a battery cell to be tested; a charging expansion change function is fitted according to the charging expansion force data; a discharging expansion change function is fitted according to the discharging expansion force data; and a key electrode affecting the service life of the battery cell to be tested is determined according to the slope size relationship between the charging expansion change function and the discharging expansion change function. In this way, the charging expansion change function is fitted by using the charging expansion force data, the discharging expansion change function is fitted by using the discharging expansion force data, and the slope size of the charging expansion change function and the discharging expansion change function is compared, so that it can be identified which electrode has a faster expansion growth, thereby the key electrode affecting the service life of the battery is determined, and the problem that the prior art cannot distinguish the expansion source direction is solved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to a method, apparatus, storage medium, and electronic device for analyzing battery cell characteristics. Background Technology

[0002] During charging, lithium ions are extracted from the positive electrode and inserted into the negative electrode, causing the negative electrode material to expand in volume. During discharging, lithium ions are extracted from the negative electrode and reinserted into the positive electrode, causing the positive electrode material to expand in volume. As charge-discharge cycles continue, the positive and negative electrodes repeatedly undergo lithium insertion and extraction processes at different stages. Each cycle produces minute deformations in the thickness direction. These deformations gradually accumulate, ultimately resulting in a continuous increase in the overall expansion force of the battery.

[0003] As the number of cycles of lithium-ion batteries increases, the expansion force continues to increase. If this exceeds the capacity of the packaging structure or the mechanical constraints of the module, it can easily lead to cell bulging, damage to the electrode-separator interface, and ultimately, internal short circuits. At the module level, excessive expansion force may also cause deformation or breakage of structural components such as end plates, side plates, or cable ties, affecting system reliability, posing safety risks such as thermal runaway, fire, or explosion, and shortening battery life.

[0004] Although battery swelling force has a significant impact on cycle life and safety, current technology has not yet been able to effectively distinguish the main sources of swelling force growth. Summary of the Invention

[0005] To overcome at least one deficiency in the prior art, this application provides a cell characteristic analysis method, apparatus, storage medium, and electronic device, which can identify key electrodes that affect battery life and solve the problem that the prior art cannot distinguish the direction of expansion source.

[0006] In a first aspect, this application provides a method for analyzing the characteristics of a battery cell, the method comprising: Acquire charging expansion force data and discharging expansion force data of the battery cell under test, wherein the charging expansion force data includes the expansion force generated by the battery cell under test during charging at different cycles, and the discharging expansion force data includes the expansion force generated by the battery cell under test during discharging at different cycles. Based on the charging expansion force data, a charging expansion change function is fitted. Based on the discharge expansion force data, a discharge expansion variation function is fitted. Based on the relationship between the slopes of the charging expansion change function and the discharging expansion change function, the key electrodes affecting the lifespan of the battery cell under test are determined.

[0007] Secondly, this application provides a battery cell characteristic analysis device, the device comprising: The data acquisition module is used to acquire charging expansion force data and discharging expansion force data of the battery cell under test. The charging expansion force data includes the expansion force generated by the battery cell under test during charging at different cycles, and the discharging expansion force data includes the expansion force generated by the battery cell under test during discharging at different cycles. The function fitting module is used to fit a charging expansion change function based on the charging expansion force data. The function fitting module is also used to fit a discharge expansion change function based on the discharge expansion force data; The cell analysis module is used to determine the key electrodes that affect the lifespan of the cell under test based on the slope relationship between the charging expansion change function and the discharging expansion change function.

[0008] Thirdly, this application provides a storage medium storing a computer program that, when executed by a processor, implements the cell characteristic analysis method.

[0009] Fourthly, this application provides an electronic device, which includes a processor and a memory. The memory stores a computer program, which, when executed by the processor, implements the cell characteristic analysis method.

[0010] Compared with the prior art, this application has the following beneficial effects: The battery cell characteristic analysis method, apparatus, storage medium, and electronic device provided in this application acquire charging expansion force data and discharging expansion force data of the battery cell under test. The charging expansion force data includes the expansion force generated by the battery cell under test during charging at different cycles, and the discharging expansion force data includes the expansion force generated by the battery cell under test during discharging at different cycles. Based on the charging expansion force data, a charging expansion change function is fitted; based on the discharging expansion force data, a discharging expansion change function is fitted; and based on the slope relationship between the charging expansion change function and the discharging expansion change function, the key electrodes affecting the lifespan of the battery cell under test are determined.

[0011] In this way, by fitting the charging expansion force data to obtain the charging expansion change function, and then fitting the discharging expansion force data to obtain the discharging expansion change function, and by comparing the slopes of the charging expansion change function and the discharging expansion change function, it is possible to identify which electrode expands faster, thereby determining the key electrode that affects battery life, and solving the problem that existing technologies cannot distinguish the direction of expansion source. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is one of the flowcharts illustrating the cell characteristic analysis method provided in the embodiments of this application; Figure 2 This is a schematic diagram of the fitting curve of the expansion force data provided in the embodiments of this application; Figure 3 A second schematic flowchart illustrating the cell characteristic analysis method provided in this application embodiment; Figure 4 The third schematic flowchart of the cell characteristic analysis method provided in the embodiments of this application; Figure 5 The fourth flowchart illustrates the cell characteristic analysis method provided in this application embodiment; Figure 6 A schematic diagram illustrating the calculation principle of the desired slope provided in the embodiments of this application; Figure 7 This is a schematic diagram of the structure of the cell characteristic analysis device provided in the embodiments of this application; Figure 8 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of the embodiments of this application (hereinafter referred to as "the embodiments") clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0015] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0016] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0017] In the description of this application, it should be noted that the terms "first," "second," "third," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0018] Based on the above statement, as introduced in the background section, although battery swelling force has a significant impact on cycle life and safety, current technologies have not yet effectively distinguished the main sources of swelling force growth.

[0019] Specifically, related studies mostly focus on the overall expansion behavior of the battery or the expansion peak at a specific state of charge, but do not fully consider the difference between the expansion force change trends at the end of charging and at the end of discharging during a complete charge-discharge cycle. Therefore, it is impossible to determine whether the expansion dominated by the negative electrode during charging or the expansion dominated by the positive electrode during discharging contributes more. Due to the fundamental differences in the positive and negative electrode reaction mechanisms of lithium-ion batteries with different material systems, it is difficult to accurately identify the key factors affecting the degradation of battery cycle performance, and it is also impossible to provide clear technical guidance for material optimization, process improvement, or structural design.

[0020] It should be noted that the defects in the solutions in the prior art are the result of practice and careful research. Therefore, the discovery process of the above problems and the solutions proposed by the embodiments of this application in the following text should be regarded as contributions to this application in the process of invention and creation, and should not be understood as technical content known to those skilled in the art.

[0021] Based on the discovery of the above-mentioned technical problems, this embodiment provides a method for analyzing battery cell characteristics. For example... Figure 1 As shown, the method includes: S1, acquire the charging expansion force data and discharging expansion force data of the battery cell under test.

[0022] The charging expansion force data includes the expansion force generated by the battery cell under test during charging at different cycles, and the discharging expansion force data includes the expansion force generated by the battery cell under test during discharging at different cycles.

[0023] S2, Based on the charging expansion force data, fit the charging expansion change function.

[0024] S3. Based on the discharge expansion force data, fit the discharge expansion change function.

[0025] S4. Based on the slope relationship between the charging expansion change function and the discharging expansion change function, determine the key electrodes that affect the lifespan of the battery cell under test.

[0026] In this way, by fitting the charging expansion force data to obtain the charging expansion change function, and then fitting the discharging expansion force data to obtain the discharging expansion change function, and by comparing the slopes of the charging expansion change function and the discharging expansion change function, it is possible to identify which electrode expands faster, thereby determining the key electrode that affects battery life, and solving the problem that existing technologies cannot distinguish the direction of expansion source.

[0027] It should be noted that, in this embodiment, the device implementing the cell characteristic analysis method can be an electronic device with data acquisition and processing capabilities. For example, general-purpose devices such as tablet computers, laptop computers, desktop computers, and servers, or embedded devices specifically developed for implementing the cell characteristic analysis method.

[0028] To make the solution provided in this embodiment clearer, a computer is used as the electronic device for implementing the method below, and in conjunction with... Figure 1 Each step of the method is described in detail. However, it should be understood that the operations in the flowchart may not be implemented in sequence, and steps without logical contextual relationships may be reversed in order or implemented simultaneously. Furthermore, those skilled in the art, guided by the content of this application, may add one or more other operations to the flowchart, or remove one or more operations from the flowchart. Continuing with 1, the method includes: S1, acquire the charging expansion force data and discharging expansion force data of the battery cell under test.

[0029] The charging expansion force data includes the expansion force generated by the battery cell under test during charging at different cycles, and the discharging expansion force data includes the expansion force generated by the battery cell under test during discharging at different cycles. As an optional implementation, the expansion force generated during charging is the expansion force measured each time the battery is charged to the cutoff voltage; the expansion force generated during discharging is the expansion force measured each time the battery is discharged to the cutoff voltage.

[0030] In this embodiment, the deformation pattern of the battery cell under test as the number of uses increases can be reflected by acquiring the expansion force data generated by the battery cell under test during the cycling process.

[0031] In practical applications, a battery module composed of lithium titanate cells can be prepared, connected in a 1-parallel, 23-series configuration to simulate the cell's operating state under real-world usage conditions. Based on this, a pressure sensor is installed on the end plate of the battery module to ensure accurate sensing of the expansion force caused by volume changes during charging and discharging.

[0032] Before testing, an initial preload of 220 kgf is applied to the pressure sensor to ensure stable contact pressure between the cells within the battery pack, preventing loosening from affecting measurement results. Subsequently, the battery module undergoes repeated charge-discharge cycle tests using a charge-discharge test cabinet. During each cycle, a constant current discharge at 3C is applied until the voltage of any single cell in the module drops to 1.8 volts; then, the cell is allowed to rest for 30 minutes to allow the internal reaction to stabilize; next, a constant current charge at the same 3C is applied until the voltage of any single cell reaches 2.65 volts. The entire testing process is conducted at room temperature (25±5℃) to eliminate the impact of drastic temperature fluctuations on battery performance and expansion behavior.

[0033] During this process, the computer records the corresponding expansion force value each time the charging reaches the cutoff voltage, forming charging expansion force data; simultaneously, it also records the corresponding expansion force value each time the discharging reaches the cutoff voltage, forming discharging expansion force data. These data respectively reflect the expansion force generated by the tested battery cell during charging and discharging at different cycles.

[0034] Based on the above description of the charging expansion force data and discharging expansion force data in the embodiments, please refer to [link to previous document]. Figure 1 Next, we will continue with... Figure 1 Steps S2 and S3 will be explained below: S2, based on the charging expansion force data, fit the charging expansion change function.

[0035] S3. Based on the discharge expansion force data, fit the discharge expansion change function.

[0036] This embodiment can be understood as follows: by converting the actual measured expansion force data into a mathematical trend model, it reflects the changing pattern of the battery's expansion behavior during the charging phase in the long-term use process.

[0037] like Figure 2As shown, in practical applications, the computer uses charging expansion force data as the basis, plotting points on a coordinate system with the number of cycles as the x-axis and the final charging expansion force as the y-axis, to draw the original change curve for the first 1500 cycles, i.e., the final charging expansion force curve. This curve visually demonstrates how the expansion force generated by the battery after each charge gradually changes as the number of cycles increases; and by using mathematical fitting methods to process the curve, a charging expansion change function that can represent the overall trend is obtained.

[0038] See also Figure 2 The expansion force of the tested battery cell increases approximately linearly with the number of cycles, so the charging expansion change function exhibits a linear relationship with a positive slope:

[0039] Therefore, the expansion force performance of the tested cell as it continues to cycle can be predicted using this charging expansion change function. The processing method for discharge expansion force data is the same as that for charging expansion force data, and will not be described again in this embodiment.

[0040] S4. Based on the relationship between the slopes of the charging expansion change function and the discharging expansion change function, determine the key electrodes that affect the lifespan of the battery cell under test.

[0041] It should be noted that when the battery cell under test is a product with improved formula or process based on the reference battery cell (for example, by modifying the formula to reduce production costs), although its material composition or manufacturing process may change, it is still necessary to ensure that its core expansion behavior is consistent with the original design in order to ensure the long-term reliability of the battery in the module.

[0042] Therefore, as an optional implementation, this embodiment obtains the standard charging expansion change function and the standard discharging expansion change function of the reference cell as a performance benchmark. Before determining the key electrodes that affect the lifespan of the cell under test, it first verifies whether the difference between the charging expansion change function of the cell under test and the standard charging expansion change function is less than a set threshold, and whether the difference between the discharging expansion change function and the standard discharging expansion change function is also less than the threshold.

[0043] In this way, even after cost optimization or process adjustments to the battery cells, it can be ensured that their key performance characteristics still meet the original design expectations.

[0044] For step S4, as an optional implementation, if the slope of the discharge expansion function is greater than the slope of the charge expansion function, the computer determines that the positive electrode of the cell under test is the key electrode affecting battery life; if the slope of the charge expansion function is greater than the slope of the discharge expansion function, the computer determines that the negative electrode is the key electrode affecting battery life.

[0045] This embodiment can be understood as follows: by comparing the growth rate of the charging expansion change function and the discharging expansion change function, it can determine whether the positive or negative electrode of the battery dominates the expansion problem during long-term cycling, thereby identifying the key electrode that affects the lifespan of the battery cell under test.

[0046] In practical applications, charging expansion force data and discharging expansion force data have been used to fit charging expansion force change function and discharging expansion force change function, respectively. These two functions reflect the changing trend of the expansion force generated by the battery at the end of each charging and discharging cycle as the number of cycles increases.

[0047] Based on this, the computer further analyzes the slopes of these two functions, where the slope represents the rate at which the expansion force increases with the number of cycles. If the slope of the discharge expansion function is greater than that of the charging expansion function, it indicates that the battery expands faster during discharge. This reflects a more significant volume change in the positive electrode material during lithium-ion insertion, meaning the rate of electrode expansion due to lithium-ion insertion in the positive electrode is greater than that in the negative electrode. Therefore, the positive electrode can be identified as the key electrode affecting the lifespan of the tested cell. Conversely, if the slope of the charging expansion function is greater than that of the discharge expansion function, it indicates more intense expansion during charging, reflecting a greater deformation of the negative electrode during lithium-ion insertion. In this case, the negative electrode is identified as the key electrode affecting the lifespan of the tested cell.

[0048] As an example, see further. Figure 2 During testing of lithium titanate batteries, it was found that the expansion force at the end of discharge was significantly higher than that at the end of charging. This indicates that the expansion behavior of this type of battery during cycling is mainly affected by the discharge stage. In other words, the process of lithium ions re-intercalating into the positive electrode during discharge is the main cause of continuous expansion. Therefore, the positive electrode is determined to be the critical electrode.

[0049] Thus, by comparing the slope relationship of the two expansion change functions, the dominant factors leading to battery performance degradation can be effectively identified, and clear directions for improvement can be provided for optimizing the cell's materials or processes.

[0050] It should be noted that during long-term cyclic use, the expansion force of the battery will continue to increase, potentially causing damage to the fixed structure. However, current technology struggles to predict when the battery module will reach the critical point of structural failure due to accumulated expansion. Therefore, if... Figure 3 , 4 As shown, the cell characteristic analysis method provided in this embodiment further includes: S5, obtain the maximum breaking force that the target cable tie can withstand.

[0051] The target cable tie is used to secure the battery module based on the cell under test.

[0052] S6A, if the negative electrode is the key electrode affecting battery life, then the number of cycles corresponding to the first cycle when the target cable tie's maximum breaking force is reached can be obtained according to the charging expansion change function.

[0053] S7A uses the number of cycles in the first test as the lifespan of the cell under test.

[0054] S6B, if the positive electrode is the key electrode affecting battery life, then the number of the second cycle corresponding to the maximum breaking force of the target cable tie can be obtained according to the discharge expansion change function.

[0055] S7B uses the number of the second cycle as the lifespan of the cell under test.

[0056] This embodiment can be understood as follows: by combining the growth trend of battery expansion force with the load-bearing limit of module structural components, the number of cycles that the battery cell under test can withstand in actual use can be predicted.

[0057] In practical applications, the computer obtains the maximum tensile force that the target cable tie can withstand. This target cable tie is a key structural component used to fix the battery module based on the battery cell under test. Its maximum tensile force represents the maximum external force that the component can withstand without breaking.

[0058] Based on this, and considering the previously identified key electrodes affecting battery life, a corresponding expansion change function is selected for analysis. If the negative electrode is the key electrode affecting the life of the cell under test, it indicates that the volume change of the negative electrode is more drastic during charging, resulting in the overall expansion behavior being mainly dominated by the charging stage. Therefore, the computer uses the charging expansion change function to calculate the trend of expansion force increasing with the number of cycles. According to the changing law of this function, the number of cycles corresponding to when the expansion force gradually rises to equal the maximum tensile force of the target cable tie is calculated, which is the first cycle number, and is taken as the lifespan of the cell under test.

[0059] Similarly, if the positive electrode is the key electrode affecting the lifespan of the battery cell under test, it indicates that the lithium intercalation behavior of the positive electrode contributes more to the expansion during the discharge process. In this case, the second cycle number corresponding to the maximum breaking force of the target cable tie should be calculated based on the discharge expansion change function, and the second cycle number should be taken as the lifespan of the battery cell under test.

[0060] It should be noted that during long-term battery cycling, the expansion behavior of the positive and negative electrodes is not synchronized. One electrode may expand significantly faster than the other due to material properties or reaction mechanisms, becoming a critical electrode affecting battery life. Without intervention, the continued rapid expansion of this critical electrode will lead to premature battery failure, even if the other electrode remains in good condition. This uneven degradation results in a premature decrease in battery performance, leading to resource waste. Therefore, if... Figure 5 As shown, the cell characteristic analysis method provided in this embodiment further includes: S6C selects the target expansion change function corresponding to the non-critical electrode from the charging expansion change function and the discharging expansion change function.

[0061] S7C, based on the target expansion change function, obtains the expected number of cycles corresponding to the maximum breaking force of the target cable tie.

[0062] S8C obtains the desired slope required to reach the desired number of iterations from the set number of intervention iterations.

[0063] The number of intervention cycles represents the number of cycles in which the charging or discharging of the battery cell under test is intervened in advance.

[0064] S9C determines the proportion of the charge or discharge amount of the cell under test that needs to be adjusted starting from the number of intervention cycles, based on the ratio between the expected slope and the slope of the target expansion function.

[0065] This embodiment can be understood as follows: by actively adjusting the charging and discharging process during battery use, the expansion rate of the critical electrode side is slowed down, so that it matches the degradation rate of the non-critical electrode side, thereby achieving a more balanced aging behavior and extending the overall battery life.

[0066] In practical applications, the computer obtains the maximum tensile force that the target cable tie can withstand. This target cable tie is a key structural component used to secure the battery module based on the cell under test, and its maximum tensile force represents the limit of the module's mechanical strength. Based on this, the critical electrode affecting the lifespan of the cell under test, i.e., the electrode on the side with faster expansion growth, has been identified through slope comparison. To prevent this critical electrode from prematurely causing structural failure or a sudden drop in performance, the computer selects a target expansion change function corresponding to the non-critical electrode from the charging expansion change function and the discharging expansion change function, using it as a benchmark for lifespan matching. Based on this target expansion change function, the expected number of cycles corresponding to when the expansion force reaches the maximum tensile force of the target cable tie is calculated, i.e., the expected lifespan end point that the non-critical electrode can withstand under normal cycling.

[0067] Furthermore, in this embodiment, a predetermined number of intervention cycles is set, indicating from which cycle the charging or discharging amount of the cell under test will be intervened in advance. Therefore, the computer calculates the desired slope required to reach the desired number of cycles from this intervention cycle number, which is the new growth trend required to slow the expansion rate of the critical electrode side to the same level as the non-critical electrodes. Then, this desired slope is compared with the slope of the original critical electrode-related expansion change function, and based on the ratio between the two, the proportion of adjustment required for the charging or discharging amount of the cell under test from the intervention cycle number is determined.

[0068] like Figure 6 As shown, assuming prediction is made using the target expansion change function of the non-critical electrode, to achieve the maximum tensile force that the target cable tie can withstand, 1918 cycles are required, with 1270 intervention cycles. If the maximum tensile force is expressed as... When the number of intervention cycles is 1270, the expansion force generated by the key electrode is Then the expected slope The following method can be used to calculate:

[0069] It should be noted here that the adjustment ratio can be determined based on the relationship between the State of Charge (SOC) and the coefficient of thermal expansion. Since the expansion characteristics of electrode materials differ across different SOC ranges, the stress accumulation rate on the critical electrode side can be effectively reduced by limiting the depth of charge or discharge to avoid high expansion rate regions. The relationship between the State of Charge (SOC) and the coefficient of thermal expansion can be obtained through experiments on similar battery cells. The relationship is assumed to be as follows:

[0070] Thus, when the expected slope When the value is 0.8, after the number of cycles is intervened, the charging depth can be controlled by limiting it to within 80% SOC, thereby slowing down the cell expansion rate and achieving the desired number of cycles that non-critical electrodes can achieve as much as possible.

[0071] Based on the same inventive concept as the cell characteristic analysis method provided in this embodiment, this embodiment also provides a cell characteristic analysis device. This device includes at least one software functional module that can be stored in a memory or embedded in an electronic device. The processor in the electronic device executes the executable module stored in the memory. For example, the software functional modules and computer programs included in this device. Please refer to... Figure 7Functionally, the device may include: Data acquisition module 11 is used to acquire charging expansion force data and discharging expansion force data of the battery cell under test. The charging expansion force data includes the expansion force generated by the battery cell under test during charging at different cycles, and the discharging expansion force data includes the expansion force generated by the battery cell under test during discharging at different cycles. The function fitting module 12 is used to fit the charging expansion change function based on the charging expansion force data; The function fitting module 12 is also used to fit the discharge expansion change function based on the discharge expansion force data; The cell analysis module 13 is used to determine the key electrodes that affect the lifespan of the cell under test based on the slope relationship between the charging expansion change function and the discharging expansion change function.

[0072] In this embodiment, the data acquisition module 11 is used to implement Figure 1 In step S1, the function fitting module 12 is used to implement... Figure 1 Steps S2 and S3 in the process; the cell analysis module 13 is used to implement Figure 1 Step S4 in the above process. Therefore, for a detailed description of each of the above modules, please refer to the specific implementation of the corresponding steps, which will not be repeated here.

[0073] Optionally, the expansion force generated during charging is the expansion force measured each time the charge reaches the cutoff voltage; The expansion force generated by the discharge is the expansion force measured each time the discharge reaches the cutoff voltage.

[0074] Optionally, the cell analysis module 13 is also specifically used for: If the slope of the discharge expansion function is greater than the slope of the charge expansion function, then the positive electrode of the cell under test is determined to be the key electrode affecting the battery life. If the slope of the charging expansion function is greater than the slope of the discharging expansion function, then the negative electrode is determined to be the key electrode affecting battery life.

[0075] Optionally, the cell analysis module 13 is also used for: Obtain the maximum tensile force that the target cable tie can withstand, wherein the target cable tie is used to fix the battery module based on the cell under test; If the negative electrode is the key electrode affecting battery life, then the number of cycles corresponding to the first cycle when the target cable tie's maximum breaking force is reached can be obtained based on the charging expansion change function. The number of cycles in the first test is taken as the lifespan of the battery cell under test. If the positive electrode is the key electrode affecting battery life, then the number of the second cycle corresponding to the maximum breaking force of the target cable tie can be obtained according to the discharge expansion change function. The number of the second cycle is taken as the lifespan of the cell under test.

[0076] Optionally, the cell analysis module 13 is also used for: Obtain the maximum tensile force that the target cable tie can withstand, wherein the target cable tie is used to fix the battery module based on the cell under test; Select the target expansion change function corresponding to the non-critical electrode from the charging expansion change function and the discharging expansion change function; Based on the target expansion change function, the expected number of cycles corresponding to the maximum breaking force of the target cable tie is obtained; Obtain the desired slope required to reach the desired number of cycles from the set number of intervention cycles, where the number of intervention cycles represents the number of cycles in which the charging or discharging amount of the battery cell under test is intervened in advance; Based on the ratio between the expected slope and the slope of the target expansion function, determine the proportion by which the charging or discharging amount of the cell under test needs to be adjusted starting from the number of intervention cycles.

[0077] Optionally, before determining the key electrodes affecting the lifespan of the battery cell under test based on the slope relationship between the charging expansion change function and the discharging expansion change function, the function fitting module 12 is also used for: Obtain the standard charging expansion change function and the standard discharging expansion change function of the reference cell; Based on the relationship between the slopes of the charging expansion function and the discharging expansion function, the execution conditions of the key electrodes affecting the lifespan of the battery cell under test are determined as follows: The difference between the charging expansion function and the standard charging expansion function is less than the threshold, and the difference between the discharging expansion function and the standard discharging expansion function is also less than the threshold.

[0078] Optionally, the cell under test is a cell with improved formulation and / or process based on the reference cell.

[0079] In addition, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0080] It should also be understood that if the above embodiments are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application.

[0081] Therefore, this embodiment also provides a storage medium, which is a computer-readable storage medium. The storage medium stores a computer program, which, when executed by a processor, implements the cell characteristic analysis method provided in this embodiment. The storage medium can be any medium capable of storing program code, such as a USB flash drive, portable hard drive, read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0082] This embodiment provides an electronic device for analyzing battery cell characteristics. For example... Figure 8 As shown, the electronic device may include a processor 22 and a memory 21. The memory 21 stores a computer program, and the processor reads and executes the computer program corresponding to the above-described embodiments in the memory 21 to implement the cell characteristic analysis method provided in this embodiment.

[0083] See also Figure 8 The electronic device also includes a communication unit 23. The memory 21, processor 22 and communication unit 23 are electrically connected to each other directly or indirectly through system bus 24 to realize data transmission or interaction.

[0084] The memory 21 can be an information recording device based on any electronic, magnetic, optical, or other physical principles, used to record execution instructions, data, etc. In some embodiments, the memory 21 can be, but is not limited to, volatile memory, non-volatile memory, memory drive, etc.

[0085] In some embodiments, the volatile memory may be random access memory (RAM); in some embodiments, the non-volatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, etc.; in some embodiments, the storage drive may be a disk drive, solid-state drive, any type of storage disk (such as optical disc, DVD, etc.), or similar storage media, or a combination thereof.

[0086] The communication unit 23 is used to send and receive data over a network. In some embodiments, the network may include a wired network, a wireless network, a fiber optic network, a telecommunications network, an intranet, the Internet, a local area network (LAN), a wide area network (WAN), a wireless local area network (WLAN), a metropolitan area network (MAN), a public switched telephone network (PSTN), a Bluetooth network, a ZigBee network, or a near field communication (NFC) network, or any combination thereof. In some embodiments, the network may include one or more network access points. For example, the network may include wired or wireless network access points, such as base stations and / or network switching nodes, through which one or more components of the service request processing system can connect to the network to exchange data and / or information.

[0087] The processor 22 may be an integrated circuit chip with signal processing capabilities, and may include one or more processing cores (e.g., a single-core processor or a multi-core processor). By way of example only, the processor described above may include a Central Processing Unit (CPU), an Application Specific Integrated Circuit (ASIC), an Application Specific Instruction-set Processor (ASIP), a Graphics Processing Unit (GPU), a Physics Processing Unit (PPU), a Digital Signal Processor (DSP), a Field Programmable Gate Array (FPGA), a Programmable Logic Device (PLD), a controller, a microcontroller unit, a Reduced Instruction Set Computing (RISC) computer, or a microprocessor, or any combination thereof.

[0088] Understandable. Figure 8 The structure shown is for illustrative purposes only. Electronic devices may also have more advanced features. Figure 8 Showing more or fewer components, or having with Figure 8 The different configurations shown. Figure 8 The components shown can be implemented using hardware, software, or a combination thereof.

[0089] It should be understood that the apparatus and methods disclosed in the above embodiments can also be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings show the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0090] The above descriptions are merely various embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for analyzing the characteristics of a battery cell, characterized in that, The method includes: Acquire charging expansion force data and discharging expansion force data of the battery cell under test, wherein the charging expansion force data includes the expansion force generated by the battery cell under test during charging at different cycles, and the discharging expansion force data includes the expansion force generated by the battery cell under test during discharging at different cycles. Based on the charging expansion force data, a charging expansion change function is fitted. Based on the discharge expansion force data, a discharge expansion variation function is fitted. Based on the relationship between the slopes of the charging expansion change function and the discharging expansion change function, the key electrodes affecting the lifespan of the battery cell under test are determined.

2. The cell characteristic analysis method according to claim 1, characterized in that, The expansion force generated during charging is the expansion force measured each time the battery is charged to the cutoff voltage. The expansion force generated by the discharge is the expansion force measured each time the discharge reaches the cutoff voltage.

3. The cell characteristic analysis method according to claim 1, characterized in that, Based on the slope relationship between the charging expansion change function and the discharging expansion change function, the key electrodes affecting the lifespan of the battery cell under test are determined, including: If the slope of the discharge expansion change function is greater than the slope of the charge expansion change function, then the positive electrode of the cell under test is determined to be the key electrode affecting the battery life. If the slope of the charging expansion change function is greater than the slope of the discharging expansion change function, then the negative electrode is determined to be the key electrode affecting the battery cell under test.

4. The cell characteristic analysis method according to claim 1, characterized in that, The method further includes: Obtain the maximum tensile force that the target cable tie can withstand, wherein the target cable tie is used to fix a battery module based on the battery cell under test; If the negative electrode is the key electrode affecting battery life, then the number of cycles corresponding to when the target cable tie reaches the maximum breaking force can be obtained according to the charging expansion change function. The number of the first cycle is taken as the service life of the battery cell under test; If the positive electrode is the key electrode affecting battery life, then the second cycle number corresponding to when the target cable tie reaches the maximum breaking force can be obtained according to the discharge expansion change function. The second cycle number is taken as the lifespan of the battery cell under test.

5. The cell characteristic analysis method according to claim 1, characterized in that, The method further includes: Obtain the maximum tensile force that the target cable tie can withstand, wherein the target cable tie is used to fix a battery module based on the battery cell under test; Select the target expansion change function corresponding to the non-critical electrode from the charging expansion change function and the discharging expansion change function; Based on the target expansion change function, the expected number of cycles corresponding to when the target cable tie reaches the maximum breaking force is obtained; Obtain the desired slope required to reach the desired number of cycles from a set number of intervention cycles, wherein the number of intervention cycles represents the number of cycles in which the charging or discharging amount of the battery cell under test is intervened in advance; Based on the ratio between the desired slope and the slope of the target expansion function, the proportion by which the charging or discharging amount of the cell under test needs to be adjusted starting from the number of intervention cycles is determined.

6. The cell characteristic analysis method according to claim 1, characterized in that, Before determining the key electrodes affecting the lifespan of the battery cell under test based on the slope relationship between the charging expansion change function and the discharging expansion change function, the method further includes: Obtain the standard charging expansion change function and the standard discharging expansion change function of the reference cell; The execution conditions for determining the key electrodes affecting the lifespan of the battery cell under test, based on the slope relationship between the charging expansion change function and the discharging expansion change function, are as follows: The difference between the charging expansion function and the standard charging expansion function is less than a threshold, and the difference between the discharging expansion function and the standard discharging expansion function is less than a threshold.

7. The cell characteristic analysis method according to claim 6, characterized in that, The cell under test is a cell whose formula and / or process have been improved based on the reference cell.

8. A battery cell characteristic analysis device, characterized in that, The device includes: The data acquisition module is used to acquire charging expansion force data and discharging expansion force data of the battery cell under test. The charging expansion force data includes the expansion force generated by the battery cell under test during charging at different cycles, and the discharging expansion force data includes the expansion force generated by the battery cell under test during discharging at different cycles. The function fitting module is used to fit a charging expansion change function based on the charging expansion force data. The function fitting module is also used to fit a discharge expansion change function based on the discharge expansion force data; The cell analysis module is used to determine the key electrodes that affect the lifespan of the cell under test based on the slope relationship between the charging expansion change function and the discharging expansion change function.

9. A storage medium, characterized in that, The storage medium stores a computer program, which, when executed by a processor, implements the cell characteristic analysis method according to any one of claims 1-7.

10. An electronic device, characterized in that, The electronic device includes a processor and a memory, the memory storing a computer program, which, when executed by the processor, implements the cell characteristic analysis method according to any one of claims 1-7.

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