Battery capacity abnormal attenuation identification method and electronic device

Abstract

The application provides a battery capacity abnormal attenuation identification method and an electronic device. Voltage data of n historical working conditions of a to-be-tested battery pack is obtained. The voltage data of the historical working conditions includes voltage values of each battery cell in the to-be-tested battery pack under the historical working conditions. For each historical working condition in the n historical working conditions, a target moment corresponding to the historical working condition is determined. According to a relationship between the voltage value of a target battery cell of the to-be-tested battery pack at the target moment and a reference voltage value of the to-be-tested battery pack, an initial battery capacity attenuation identification result of the target battery cell corresponding to the historical working condition is determined. The reference voltage value is a maximum voltage value or a minimum voltage value in the voltage values of each battery cell of the to-be-tested battery pack at the target moment. According to the initial battery capacity attenuation identification results of the target battery cells corresponding to the n historical working conditions respectively, a target battery capacity attenuation identification result of the target battery cell is determined. The application embodiment can improve the accuracy of capacity abnormal attenuation identification.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a method for identifying abnormal battery capacity attenuation and an electronic device. Background Art

[0002] During the lithium battery manufacturing process, abnormal capacity decay refers to the presence of certain defects inside the battery that cause the performance of a single cell to be lower than normal. During the manufacturing and use of lithium batteries, the traditional method of identifying abnormal capacity decay mainly relies on the qualitative judgment of voltage changes during the charging process, that is, it only relies on whether the cell number corresponding to the initial lowest voltage is consistent with the cell number of the highest voltage at the charging cutoff moment to determine whether there is abnormal capacity decay. In fact, most battery packs do not have such a serious short-board effect. The voltage is neither the lowest at the beginning of charging nor the highest at the end of charging. Therefore, this identification method based on a single voltage change is difficult to fully cover all factors that may cause abnormal cell capacity decay. Therefore, the traditional method of identifying abnormal capacity decay has a limited recognition range, resulting in low accuracy in identifying abnormal capacity decay. Summary of the Invention

[0003] The present application provides a method for identifying abnormal battery capacity attenuation and an electronic device, which can improve the accuracy of identifying abnormal battery capacity attenuation.

[0004] In a first aspect, an embodiment of the present application provides a method for identifying abnormal battery capacity degradation, the method comprising:

[0005] Obtain voltage data of n historical operating conditions of the battery pack to be tested, where n is a positive integer, the n historical operating conditions include at least one of a constant current charging condition, a non-constant current charging condition, and a discharge condition, and the voltage data of the historical operating conditions include the voltage value of each cell in the battery pack to be tested under the historical operating conditions;

[0006] For each of the n historical operating conditions, determine a target time corresponding to the historical operating condition;

[0007] Determine the initial battery capacity attenuation identification result corresponding to the target cell and the historical operating condition based on the relationship between the voltage value of the target cell of the battery pack to be tested at the target time and the reference voltage value of the battery pack to be tested; the reference voltage value is the maximum voltage value or the minimum voltage value of the battery pack to be tested at the target time;

[0008] According to the initial battery capacity attenuation identification results of the target battery cell corresponding to the n historical operating conditions, a target battery capacity attenuation identification result of the target battery cell is determined.

[0009] In a second aspect, the present application provides a device for identifying abnormal battery capacity attenuation, the device comprising:

[0010] an acquisition module, configured to acquire voltage data of n historical operating conditions of the battery pack to be tested, wherein n is a positive integer, the n historical operating conditions include at least one of a constant current charging condition, a non-constant current charging condition, and a discharge condition, and the voltage data of the historical operating conditions includes the voltage value of each cell in the battery pack to be tested under the historical operating conditions;

[0011] A first determination module is configured to determine, for each of the n historical operating conditions, a target time corresponding to the historical operating condition;

[0012] The second determination module is used to determine the initial battery capacity attenuation identification result corresponding to the target cell and the historical operating condition based on the relationship between the voltage value of the target cell of the battery pack to be tested at the target time and the reference voltage value of the battery pack to be tested; the reference voltage value is the maximum voltage value or the minimum voltage value among the voltage values ​​of the cells of the battery pack to be tested at the target time;

[0013] The third determination module is used to determine the target battery capacity attenuation identification result of the target battery cell according to the initial battery capacity attenuation identification results of the target battery cell corresponding to the n historical operating conditions.

[0014] In a third aspect, an embodiment of the present application provides an electronic device, the electronic device comprising: a processor and a memory storing computer program instructions;

[0015] When the processor executes the computer program instructions, the method for identifying abnormal battery capacity attenuation in any one of the embodiments of the first aspect is implemented.

[0016] In a fourth aspect, an embodiment of the present application provides a computer storage medium having computer program instructions stored thereon. When the computer program instructions are executed by a processor, a method for identifying abnormal battery capacity attenuation as in any one of the embodiments in the first aspect is implemented.

[0017] In a fifth aspect, an embodiment of the present application provides a computer program product. When the instructions in the computer program product are executed by a processor of an electronic device, the electronic device executes the method for identifying abnormal battery capacity attenuation as in any one of the embodiments in the first aspect above.

[0018] In a sixth aspect, an embodiment of the present application further provides a vehicle, the vehicle comprising at least one of the following:

[0019] The battery capacity abnormal attenuation identification device according to the second aspect;

[0020] Such as the electronic equipment of the third aspect;

[0021] The computer-readable storage medium of the fourth aspect.

[0022] In a battery capacity abnormal attenuation identification method and electronic device provided in an embodiment of the present application, by obtaining voltage data of a battery pack to be tested under multiple historical operating conditions, for each historical operating condition, the maximum or minimum voltage value of each battery cell at its corresponding target moment is selected as a reference voltage, and then based on the relationship between the voltage value of the target battery cell at the target moment and the reference voltage, the initial battery capacity attenuation identification result of the target battery cell under the historical operating condition is determined. Finally, based on the initial battery capacity attenuation identification results of the target battery cell under multiple historical operating conditions, a target battery capacity attenuation identification result of the target battery cell is obtained through a comprehensive evaluation. This comprehensive analysis based on voltage data under multiple historical operating conditions effectively avoids the problem of limited identification range caused by a single voltage change judgment in traditional methods. By conducting in-depth analysis of the voltage data of each battery cell under different historical operating conditions, the capacity status of each battery cell can be judged more accurately, and a more reliable target battery capacity attenuation identification result can be obtained, thereby improving the accuracy of abnormal capacity attenuation identification. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0024] Figure 1 1 is a flow chart of a method for identifying abnormal battery capacity attenuation provided in an embodiment of the present application;

[0025] Figure 2 Schematic diagram of the principle of the method for identifying abnormal battery capacity attenuation provided in an embodiment of the present application;

[0026] Figure 3 This is a schematic structural diagram of a device for identifying abnormal battery capacity attenuation provided in an embodiment of the present application;

[0027] Figure 4 It is a structural diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0028] In order to more clearly understand the above-mentioned objectives, features and advantages of the present disclosure, the scheme of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features therein can be combined with each other in the absence of conflict.

[0029] In the following description, many specific details are set forth to facilitate a full understanding of the present disclosure, but the present disclosure may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present disclosure, rather than all of the embodiments.

[0030] It is to be noted that, in the present document, relational terms such as "first" and "second", and the like, can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", "has", "having", "includes", "including", or the like, are inclusive and are used as equivalents of the term "comprising" only where the context requires it, to avoid the use of the term "comprising" in an exclusive sense. The term "consisting essentially of to avoid the use of the term "comprising" in an exclusive sense, means including, but not limited to, the elements listed after the term, and excluding other elements of equivalent functionality to the listed elements.

[0031] In the lithium battery manufacturing process, capacity abnormal attenuation cells refer to those single batteries whose performance is significantly lower than the normal standard due to internal defects. The causes of these defective cells are diverse, mainly covering the following aspects: first, material inconsistency is an important factor, and the quality fluctuations of positive and negative electrode materials and electrolyte can lead to inconsistency of cell performance; second, manufacturing process defects, such as poor winding, poor alignment of laminated sheets, or welding defects, can also significantly affect the uniformity and stability of the cells; third, environmental factors such as improper humidity and temperature control in the production environment cannot be ignored; finally, physical damage during transportation or storage can also cause abnormal capacity attenuation of the cells.

[0032] The existence of capacity abnormal attenuation cells poses a serious threat to the overall performance of the battery pack. On the one hand, they can cause safety hazards, and in extreme cases, even lead to overheating, short circuit, fire or explosion, etc. On the other hand, these cells will reduce the overall efficiency of the battery pack, leading to performance degradation; in addition, they will also accelerate the aging process of adjacent healthy cells, thereby significantly reducing the service life of the entire battery system.

[0033] To address this problem, the traditional approach generally adopts a qualitative judgment method based on the comparison of the minimum voltage of the charging starting cell and the maximum voltage of the charging end cell to identify capacity abnormal attenuation cells. However, this method has obvious limitations, as it cannot comprehensively cover all types of capacity abnormal attenuation cells, nor can it accurately quantify the degree of capacity attenuation of individual cells. In fact, most battery packs do not exhibit such obvious short board effects, and many cells are not the lowest voltage at the start of charging, nor the highest voltage at the end of charging, so this method is not effective in identifying potential problem cells.

[0034] Furthermore, traditional methods lack a quantitative assessment of the extent of the shortcomings of cells experiencing abnormal capacity degradation, making the identification results ineffective. Managers are unable to accurately determine whether the identified cells meet the standards for replacement or repair, which undoubtedly increases the safety risks and maintenance costs of battery pack operations. Therefore, there is an urgent need to develop more advanced and accurate technologies for identifying cells experiencing abnormal capacity degradation to comprehensively assess cell performance and ensure the safe and stable operation of battery packs.

[0035] In order to solve the problems existing in the related art, the embodiments of the present application provide a method for identifying abnormal battery capacity attenuation and an electronic device. The execution subject of the method for identifying abnormal battery capacity attenuation of the present application can be a vehicle, and further, it can be the battery management system (BMS) of the vehicle. The vehicle can be a private car, such as a sedan, SUV, MPV or pickup truck. The vehicle can also be an operating vehicle, such as a van, bus, small truck or large trailer. The vehicle can be a gasoline vehicle or a new energy vehicle. When the vehicle is a new energy vehicle, it can be a hybrid vehicle or a pure electric vehicle.

[0036] like Figure 1 As shown, the method specifically includes the following steps:

[0037] S100, obtaining voltage data of n historical operating conditions of the battery pack to be tested; n is a positive integer, the n historical operating conditions include at least one of a constant current charging condition, a non-constant current charging condition, and a discharge condition, and the voltage data of the historical operating conditions include the voltage value of each cell in the battery pack to be tested under the historical operating conditions.

[0038] Optionally, historical operating conditions refer to specific operating states or conditions that the battery pack under test has experienced in the past. In this embodiment of the present application, historical operating conditions include at least one of constant current charging conditions, non-constant current charging conditions, and discharge conditions. These conditions are used to comprehensively evaluate the performance of the battery pack under different conditions.

[0039] Optionally, the battery pack under test refers to a battery pack or battery module for which battery capacity degradation identification is required. This may be a newly manufactured battery pack or an already-in-use battery pack requiring performance evaluation or fault diagnosis. The battery pack under test is composed of multiple cells connected in series or parallel.

[0040] Optionally, in a feasible implementation of the present application, the voltage data of n historical operating conditions of the battery pack to be tested can be collected through the BMS. Specifically, first, the BMS will use the voltage sensor installed on each battery cell to collect the voltage data of each battery cell in the battery pack under various operating conditions in real time. Then, the BMS will preprocess the collected raw voltage data, including noise removal, calibration and formatting, to ensure the accuracy and consistency of the data. After the preprocessing is completed, the BMS will store the voltage data in chronological order and operating condition type to form a historical operating condition database. This database not only contains the voltage value of each battery cell under specific operating conditions, but also records key parameters such as the start time, duration, and current of the operating condition, providing a rich information basis for subsequent capacity attenuation identification.

[0041] S200 : For each of n historical operating conditions, determine a target time corresponding to the historical operating condition.

[0042] Optionally, the target moment refers to a specific time point within each historical operating condition that is selected for analyzing the voltage characteristics of each cell in the battery pack under test. These target moments can be selected based on specific analysis requirements or criteria, such as a certain stage of the charging process, the end of discharge, or the moment when the battery state changes significantly.

[0043] The target time is closely linked to each historical operating condition. Specifically, for each of the n historical operating conditions, there is one or more corresponding target times. These target times are used to capture and record the voltage data of the battery pack under test under that condition for subsequent analysis.

[0044] For example, under constant current charging conditions, the target time can be selected at a certain time point after the charging current stabilizes to evaluate the charging performance and voltage response of the battery pack. Under non-constant current charging conditions, the target time can be selected at the key point where the charging current changes to observe the adaptability of the battery pack to different charging rates. Under discharge conditions, the target time can be selected before the end of discharge or at a specific stage during the discharge process to evaluate the discharge capacity and voltage stability of the battery pack.

[0045] By selecting appropriate target moments in different historical operating conditions and collecting voltage data at these moments, we can gain a more comprehensive understanding of the attenuation of each cell in the battery pack under test, providing strong data support for subsequent analysis and judgment.

[0046] S300, determining the initial battery capacity attenuation identification result corresponding to the target cell and the historical operating condition based on the relationship between the voltage value of the target cell of the battery pack to be tested at the target moment and the reference voltage value of the battery pack to be tested; the reference voltage value is the maximum voltage value or the minimum voltage value of the battery pack to be tested at the target moment.

[0047] Optionally, the target cell refers to the cell selected for capacity fade analysis under the current historical operating conditions. The battery pack to be tested contains multiple cells, and the target cell can be selected based on specific analysis requirements or criteria. For example, the cell with the largest voltage change, any cell, or a representative cell (such as the last fully charged cell) can be selected.

[0048] The reference voltage value is the maximum or minimum voltage value among the cell voltages in the battery pack under test at the target time. This value serves as a benchmark for evaluating the target cell voltage performance. The choice of maximum or minimum voltage as the reference depends on the analysis purpose and the characteristics of the battery pack. For example, the maximum or minimum voltage value can be selected to evaluate voltage differences between cells.

[0049] Optionally, the initial battery capacity decay identification result refers to a preliminary judgment on whether the target battery cell has abnormal capacity decay under the current historical operating conditions based on the relationship between the voltage value of the target battery cell and the reference voltage value. This identification result is binary, that is, whether abnormal capacity decay exists or not. In the embodiment of the present application, the initial battery capacity decay identification result can not only determine whether the battery has decayed, but also further quantitatively evaluate the specific degree of its decay.

[0050] The relationship between the target cell's voltage and the reference voltage is key to determining whether the target cell has experienced abnormal capacity decay. Specifically, this relationship can be quantified by calculating the voltage difference (i.e., the difference between the target cell's voltage and the reference voltage). If the voltage difference is significant (for example, exceeding a preset threshold), it may indicate abnormal capacity decay in the target cell.

[0051] In addition to determining the relationship between the voltage value of the target cell and the reference voltage value by directly comparing the absolute difference between the voltage value of the target cell and the reference voltage value, it is also possible to determine whether the target cell has abnormal capacity attenuation by considering the relative relationship between these values ​​(such as the proportion of the voltage difference). Specifically, the ratio of the target cell voltage difference (i.e., the difference between the target cell voltage and the reference voltage) to the difference between the maximum voltage and the minimum voltage (i.e., the overall voltage difference range) can be calculated. If the ratio is too high or too low, it may also indicate abnormal capacity attenuation of the cell.

[0052] Optionally, in a feasible implementation of the present application, the relationship between the voltage performance of the target cell and the reference voltage value is quantitatively evaluated by calculating the difference between the target cell voltage value and the reference voltage value (i.e., the voltage difference), or further calculating the ratio of the difference to the overall voltage difference range (i.e., the difference between the maximum voltage and the minimum voltage). If the voltage difference significantly exceeds a preset threshold, or the ratio of the difference to the overall voltage difference range is too high, it may indicate that the target cell has abnormal capacity attenuation.

[0053] Optionally, in another feasible implementation of the present application, in addition to considering the relationship between the voltage value of the target battery cell at a target moment under specific historical operating conditions and the reference voltage value, a time dimension analysis is also introduced, that is, comparing the voltage difference ratio or voltage difference at different target moments (such as the starting moment and the ending moment) to more comprehensively evaluate whether the target battery cell has abnormal capacity attenuation.

[0054] Specifically, first select the target cell and record its voltage value at the start and end time (or other key time nodes). At the same time, determine the maximum voltage value or minimum voltage value in the battery pack to be tested at these times as the reference voltage value. Next, calculate the voltage difference between the target cell and the reference voltage value at each moment, and calculate the proportion of these differences in the overall voltage difference range (that is, the difference between the maximum voltage and the minimum voltage) to obtain the voltage difference proportion at the start and end time.

[0055] By comparing the voltage difference percentage or voltage difference at the start and end, it can be determined whether the voltage performance of the target cell has changed significantly over time. If the voltage difference percentage or voltage difference at the start and end are similar and both remain within the normal range, the target cell's capacity decay can be considered normal. Conversely, if there is a significant difference in the voltage difference percentage or voltage difference between the start and end, especially if the voltage difference percentage at the end is too high or the voltage difference increases significantly, then the target cell is experiencing abnormal capacity decay.

[0056] In addition, by quantitatively analyzing the relationship between the voltage value of the target cell of the battery pack to be tested and the reference voltage value of the battery pack to be tested, the specific degree of abnormal cell capacity attenuation can be further evaluated, providing an important basis for the health status monitoring and maintenance of the battery pack.

[0057] S400 , determining a target battery capacity attenuation identification result of a target battery cell according to the initial battery capacity attenuation identification results of the target battery cells corresponding to n historical operating conditions.

[0058] Optionally, the target battery capacity decay identification result is a comprehensive assessment of the capacity decay of the target cell in the battery pack under test under all historical operating conditions. It is derived through further analysis and processing based on the initial battery capacity decay identification results corresponding to the n historical operating conditions mentioned in S400. This target battery capacity decay identification result not only considers the capacity decay under a single historical operating condition, but also combines information from multiple historical operating conditions, thereby being able to more comprehensively and accurately reflect the capacity decay status of the target cell in the battery pack under test.

[0059] Optionally, in a feasible implementation of the present application, the number of operating conditions that are determined to have abnormal capacity attenuation in all historical operating conditions, as well as the degree of difference between the target battery cell voltage and the reference voltage under these operating conditions can be counted (for example, by calculating statistics such as the average value, maximum value or standard deviation of the voltage difference). If the initial battery capacity attenuation identification results under most historical operating conditions indicate that there is abnormal capacity attenuation, or the degree of voltage difference exceeds a preset threshold, it will be concluded that the target battery cell has target battery capacity attenuation. On the contrary, if the identification results under only a few operating conditions are abnormal, and the degree of voltage difference is small, it can be considered that the capacity attenuation of the target battery cell is within the normal range.

[0060] Furthermore, to achieve more refined judgments, the mutual influence of different operating conditions can be further considered. For example, the capacity decay under constant-current charging conditions may affect the judgment results under non-constant-current charging and discharging conditions. By combining these analysis methods, a comprehensive and accurate target battery capacity decay identification result for the target cell in the battery pack under test can be obtained based on the initial judgment results of n historical operating conditions, providing an important reference for the subsequent maintenance and use of the battery pack.

[0061] In a method for identifying abnormal battery capacity attenuation provided in an embodiment of the present application, by obtaining voltage data of a battery pack to be tested under multiple historical operating conditions, for each historical operating condition, the maximum or minimum voltage value of each battery cell at its corresponding target moment is selected as a reference voltage, and then based on the relationship between the voltage value of the target battery cell at the target moment and the reference voltage, the initial battery capacity attenuation identification result of the target battery cell under the historical operating condition is determined. Finally, based on the initial battery capacity attenuation identification results of the target battery cell under multiple historical operating conditions, a comprehensive evaluation is performed to obtain a target battery capacity attenuation identification result for the target battery cell. This comprehensive analysis based on voltage data under multiple historical operating conditions effectively avoids the problem of limited identification range caused by a single voltage change judgment in traditional methods. By conducting in-depth analysis of the voltage data of each battery cell under different historical operating conditions, the capacity status of each battery cell can be judged more accurately, and a more reliable target battery capacity attenuation identification result can be obtained, thereby improving the accuracy of abnormal capacity attenuation identification.

[0062] In one embodiment, determining an initial battery capacity attenuation identification result corresponding to the target cell and the historical operating condition based on a relationship between a voltage value of the target cell of the battery pack to be tested and a reference voltage value of the battery pack to be tested at a target time includes:

[0063] Obtaining the maximum voltage value and the minimum voltage value of the battery pack to be tested at the target time, and the target voltage value of the target cell at the target time;

[0064] Determine the target voltage difference ratio corresponding to the historical operating condition based on the maximum voltage value, the minimum voltage value, and the target voltage value; wherein the target voltage difference ratio represents the relationship between the voltage value of the target cell of the battery pack to be tested and the reference voltage value of the battery pack to be tested at the target time;

[0065] According to the target voltage difference ratio, the initial battery capacity attenuation identification result corresponding to the target battery cell and the historical operating conditions is determined.

[0066] Optionally, the target voltage difference ratio provides a quantitative way to describe the degree of deviation of the target voltage value of the target battery cell relative to the reference voltage (maximum or minimum voltage value).

[0067] Optionally, in a feasible implementation of the present application, the target voltage difference ratio is obtained by dividing the voltage difference between the target cell and the reference voltage value (which can be the maximum voltage value or the minimum voltage value, depending on the evaluation logic) by the overall voltage difference range (i.e., the difference between the maximum voltage and the minimum voltage). The size of the target voltage difference ratio directly reflects the relative position of the voltage of the target cell in the overall voltage distribution of the battery pack, and the degree of difference between it and the reference voltage.

[0068] After calculating the target voltage differential ratio, a threshold comparison can be performed against this target voltage differential ratio based on preset thresholds or rules to determine the initial battery capacity decay identification result for the battery pack under test under the current historical operating conditions. If the target voltage differential ratio significantly exceeds the preset threshold, or differs significantly from the ratio under normal conditions, it can be determined that the target battery cell has experienced abnormal capacity decay.

[0069] In addition, in order to more comprehensively evaluate the performance of the target battery cell, the time dimension analysis can also be introduced. This means that in addition to considering the voltage performance of the target battery cell at a target moment under specific historical operating conditions, the voltage values ​​of the target battery cell at two target moments, the start moment and the end moment (or other key time nodes), can also be recorded, and the voltage difference ratio or voltage difference at these moments can be calculated. By comparing the voltage difference ratio or voltage difference at different moments, it can be determined whether the voltage performance of the target battery cell has changed significantly over time, thereby further confirming its capacity attenuation.

[0070] In these optional embodiments, the target voltage differential ratio is calculated by accurately acquiring the voltage data of each cell in the battery pack under test at the target time, thereby effectively evaluating the relationship between the target cell voltage and the overall voltage distribution of the battery pack under test. This evaluation method not only improves the accuracy of battery capacity decay identification, but also makes the evaluation results more objective and measurable through the quantitative indicator of the target voltage differential ratio, achieving a precise quantitative assessment of battery pack capacity decay, which helps to improve the efficiency and accuracy of the battery management system.

[0071] In one embodiment, when the historical operating condition is a constant current charging condition, the target battery cell is a fully charged cell of the battery pack to be tested in the previous charging condition of the constant current charging condition;

[0072] Based on the maximum voltage value, minimum voltage value, and target voltage value, determine the target pressure difference ratio corresponding to the historical operating conditions, including:

[0073] determining a first voltage difference between the maximum voltage value and the minimum voltage value;

[0074] determining a second voltage difference between the target voltage value and the minimum voltage value;

[0075] The ratio of the second pressure difference to the first pressure difference is determined as the target pressure difference ratio;

[0076] Based on the target voltage difference ratio, determine the initial battery capacity attenuation identification results corresponding to the target cell and historical operating conditions, including:

[0077] When the target voltage difference ratio is less than the first preset threshold, determining that the initial battery capacity attenuation identification result corresponding to the target battery cell and the historical operating condition is that the target battery cell has a capacity attenuation abnormality;

[0078] When the target voltage difference ratio is greater than or equal to the first preset threshold, it is determined that the initial battery capacity decay identification result corresponding to the target battery cell and the historical operating condition is that the target battery cell does not have a capacity decay abnormality.

[0079] Optionally, in a specific implementation of the present application, as Figure 2 As shown, first identify a specific constant current charging condition, which must meet the requirements that the voltage change per unit charge (1% state of charge (SOC)) is greater than 10mV, and the current standard deviation of the constant current charging section is less than 0.2, while ensuring that the charging starting SOC of the constant current charging condition is not higher than 60%. On this basis, select the fully charged cell (id_full, i.e. Figure 2 volt_cell_full in the current constant current charging process) as the target cell and pay attention to its voltage curve changes during the current constant current charging process.

[0080] Next, calculate the first voltage difference (ΔV_0) between the maximum voltage value (maxv) and the minimum voltage value (minv) of the battery to be tested at the target moment, the second voltage difference (ΔV_0-ΔV_full) between the current voltage value of the target battery cell (i.e., the target voltage value, V_full) and the minimum voltage value, and the third voltage difference (ΔV_full) between the current voltage value of the target battery cell (i.e., the target voltage value, V_full) and the maximum voltage value.

[0081] Subsequently, the target pressure difference ratio (Cap_soh_index) is calculated, that is, the ratio of the second pressure difference to the first pressure difference. According to the value of the target pressure difference ratio, the initial battery capacity attenuation identification result corresponding to the historical operating condition can be determined. Specifically, when Cap_soh_index is between 0 and 1 (that is, the target pressure difference ratio is less than the first preset threshold), it is considered that the target battery cell has a capacity attenuation anomaly under this constant current charging condition, and the smaller the target pressure difference ratio, the greater the capacity attenuation of the target battery cell and the more serious the short board; and when Cap_soh_index is greater than or equal to 1 (that is, the first preset threshold), it is judged that the target battery cell does not have a capacity attenuation anomaly under this constant current charging condition.

[0082] It's important to note that a cell's voltage change is closely related to its capacity state. Under the same charging or discharging conditions, cells with larger capacities experience relatively small voltage changes, while cells with smaller capacities experience relatively large voltage changes. Therefore, the voltage difference between cells can reflect the capacity difference between them. The previously fully charged cell was chosen as the target cell because it reached its highest voltage state during the previous charging process—the fully charged state. This makes its voltage change during the current charging process representative, reflecting the capacity state of the battery pack after a period of use and degradation.

[0083] By calculating the ratio (Cap_soh_index) of the voltage difference between the current target cell voltage and the minimum voltage (ΔV_0-ΔV_full) to the maximum voltage difference (ΔV_0) of the cell voltages in the entire battery pack, a quantitative indicator can be obtained to evaluate the capacity decay of the battery pack. The closer this ratio is to 1, the closer the voltage change of the target cell is to the voltage change of the entire battery pack. In other words, the smaller the capacity difference between the cells, the milder the capacity decay of the battery pack. Conversely, if the ratio is small, it means that the voltage change of the target cell is large relative to the voltage change of the entire battery pack, which is caused by the large capacity decay of the target cell.

[0084] In these optional embodiments, by selecting a fully charged cell from the last charging condition as the target cell and calculating the ratio of its voltage change to the maximum range of the battery pack voltage change (the target voltage difference ratio), the voltage difference between the cells can be quantified and analyzed, thereby evaluating the battery pack's capacity decay. By setting a preset threshold to determine whether the capacity decay is abnormal, the evaluation process is more objective and reliable, helping to extend the battery pack's service life and improve the stability and safety of the overall system.

[0085] In one embodiment, after determining that the initial battery capacity decay identification result corresponding to the target battery cell and the historical operating condition is that the target battery cell has a capacity decay abnormality, the method further includes:

[0086] Obtaining the charging ampere-hours of the target battery cell between the third moment and the fourth moment; wherein, at the third moment, the maximum voltage value among the voltage values ​​of the battery cells of the battery pack to be tested is equal to the target voltage value; and at the fourth moment, the minimum voltage value among the voltage values ​​of the battery cells of the battery pack to be tested is equal to the target voltage value;

[0087] determining a third voltage difference (ΔV_full) between the maximum voltage value and the target voltage value;

[0088] The ratio of the first value to the first voltage difference is determined as the attenuation capacity of the target battery cell; wherein the first value is the product of the charging ampere-hour and the third voltage difference.

[0089] Optionally, in a feasible implementation of the present application, in order to more comprehensively evaluate the capacity loss of the battery pack, another indicator can be calculated: attenuation capacity (Cap_index), which represents the minimum capacity directly lost due to abnormal cell capacity attenuation. This indicator can be calculated by considering the cumulative charging ampere-hours (ΔAh) of a constant current segment (t1 (i.e., the third moment) to t2 (i.e., the fourth moment)) in the constant current charging condition and the voltage change of the target battery cell.

[0090] Specifically, the attenuation capacity of the target cell can be calculated by formula (1) and formula (2), wherein the first value is ΔAh*ΔV_full. Figure 2 As shown, time t1 refers to the time when the maximum cell voltage in the battery pack under test reaches the current v_full voltage value, and time t2 refers to the time when the minimum cell voltage in the battery pack under test reaches the current v_full voltage value. ΔAh1 is the ampere-hour value from time t1 to the target time, and ΔAh2 is the ampere-hour value from the target time to time t2. The specific formulas (1) and (2) are as follows:

[0091]

[0092] Cap_index = ΔAh * ΔV_full / ΔV_0 (2)

[0093] In these optional embodiments, the ratio of the product of the charge ampere-hours and the third voltage difference to the first voltage difference is used to determine the decay capacity. This not only provides a quantitative assessment indicator of capacity decay anomalies, but also helps to more accurately determine the capacity decay status of the target battery cell, providing strong data support for subsequent battery cell maintenance, replacement, or performance optimization. This method improves the accuracy and reliability of battery cell performance monitoring by the battery management system.

[0094] In one embodiment, the target time includes a first time in a first stage of the historical operating condition and a second time in a second stage of the historical operating condition; in the first stage, the power of the battery pack to be tested is less than a first preset power, in the second stage, the power of the battery pack to be tested is greater than a second preset power, and the first preset power is less than the second preset power;

[0095] The maximum voltage value includes a first maximum voltage value among the voltage values ​​of each cell of the battery pack to be tested at a first moment, and a second maximum voltage value among the voltage values ​​of each cell of the battery pack to be tested at a second moment; the minimum voltage value includes a first minimum voltage value among the voltage values ​​of each cell of the battery pack to be tested at the first moment, and a second minimum voltage value among the voltage values ​​of each cell of the battery pack to be tested at the second moment;

[0096] The target voltage value includes a first voltage value of the target battery cell at a first moment and a second voltage value of the target battery cell at a second moment;

[0097] When the historical operating condition is a charging condition, the target cell is the cell other than the cell with the lowest voltage in the battery pack to be tested at the second moment; when the historical operating condition is a discharging condition, the target cell is the cell other than the cell with the highest voltage in the battery pack to be tested at the first moment;

[0098] Based on the maximum voltage value, minimum voltage value, and target voltage value, determine the target pressure difference ratio corresponding to the historical operating conditions, including:

[0099] determining a fourth voltage difference based on the first voltage value, the first minimum voltage value, and the first maximum voltage value; wherein, when the historical operating condition is a charging operating condition, the fourth voltage difference is a difference between the first voltage value and the first minimum voltage value; and when the historical operating condition is a discharging operating condition, the fourth voltage difference is a difference between the first maximum voltage value and the first voltage value;

[0100] determining a fifth voltage difference between the first maximum voltage value and the first minimum voltage value;

[0101] determining a sixth voltage difference based on the second voltage value, the second minimum voltage value, and the second maximum voltage value; wherein, when the historical operating condition is a charging condition, the sixth voltage difference is a difference between the second voltage value and the second minimum voltage value; and when the historical operating condition is a discharging condition, the sixth voltage difference is a difference between the second maximum voltage value and the second voltage value;

[0102] determining a seventh voltage difference between the second maximum voltage value and the second minimum voltage value;

[0103] A target pressure difference ratio corresponding to the historical operating condition is determined according to the fourth pressure difference, the fifth pressure difference, the sixth pressure difference, and the seventh pressure difference.

[0104] In one embodiment, determining the target pressure difference ratio corresponding to the historical operating condition based on the fourth pressure difference, the fifth pressure difference, the sixth pressure difference, and the seventh pressure difference includes:

[0105] When the historical operating condition is a charging operating condition and the target battery cell is the lowest voltage cell of the battery pack to be tested at the first moment, a ratio of the second value to the seventh voltage difference is determined as the target voltage difference ratio; wherein the second value is a difference between the seventh voltage difference and the sixth voltage difference;

[0106] When the historical operating condition is a discharge operating condition and the target battery cell is the highest voltage cell of the battery pack to be tested at the second moment, a ratio of the third value to the seventh voltage difference is determined as the target voltage difference ratio; wherein the third value is a difference between the fifth pressure difference and the fourth pressure difference;

[0107] When the target cell is a cell other than the lowest voltage cell and the highest voltage cell in the battery pack to be tested at the first moment and the second moment, the ratio of the fourth pressure difference to the fifth pressure difference is determined as the first pressure difference ratio; the ratio of the sixth pressure difference to the seventh pressure difference is determined as the second pressure difference ratio; wherein, the target pressure difference ratio includes the first pressure difference ratio and the second pressure difference ratio; the first pressure difference ratio represents the first relationship between the voltage value of the target cell of the battery pack to be tested at the first moment and the reference voltage value of the battery pack to be tested; the second pressure difference ratio represents the second relationship between the voltage value of the target cell of the battery pack to be tested at the second moment and the reference voltage value of the battery pack to be tested.

[0108] Optionally, in a specific implementation of the present application, under charging or discharging conditions, a complete charging or discharging process is first identified, and two key charging or discharging moments are determined: the first moment (corresponding to the battery pack power being less than a first preset power, such as 60% SOC) and the second moment (corresponding to the battery pack power being greater than a second preset power, such as 90% SOC). At these two moments, the voltage value of each cell in the battery pack is recorded respectively, and the maximum voltage value and the minimum voltage value are calculated.

[0109] Under charging conditions, at the first moment, the calculated difference between the first maximum voltage value (maxv_1) and the first minimum voltage value (minv_1) is the maximum voltage difference of the battery pack at that moment (i.e., the fifth voltage difference, ΔV_1). Then, for any battery cell in the battery pack, the difference between its first voltage value (V_1_i) and the first minimum voltage value (minv_1) is calculated to obtain the voltage difference of that battery cell (i.e., the fourth voltage difference, ΔV_1_i). The first voltage difference ratio is the ratio of the voltage difference of that battery cell (ΔV_1_i) to the maximum voltage difference of the battery pack (ΔV_1). It represents the relationship between the voltage of that battery cell and the overall voltage distribution of the battery pack at the first moment.

[0110] Similarly, at the second moment, the calculated difference between the second maximum voltage value (maxv_2) and the second minimum voltage value (minv_2) is the maximum voltage difference of the battery pack at that moment (i.e., the seventh voltage difference, ΔV_2). For the same battery cell, the difference between its second voltage value (V_2_i) and the second minimum voltage value (minv_2) is calculated to obtain the voltage difference of the battery cell (i.e., the sixth voltage difference, ΔV_2_i). The second voltage difference ratio is the ratio of the voltage difference of the battery cell (ΔV_2_i) to the maximum voltage difference (ΔV_2) of the battery pack at the second moment. It represents the relationship between the voltage of the battery cell at the second moment and the overall voltage distribution of the battery pack.

[0111] Under discharge conditions, at the first moment, the calculated difference between the first maximum voltage value and the first minimum voltage value (the fifth voltage difference) is the maximum voltage difference of the battery pack at that moment. Then, for any battery cell in the battery pack, the difference between its voltage value and the first maximum voltage value (the fourth voltage difference) is calculated to obtain the voltage difference of the battery cell. The first voltage difference ratio is the ratio of the voltage difference of the battery cell to the maximum voltage difference of the battery pack, which represents the relationship between the voltage of the battery cell and the overall voltage distribution of the battery pack at the first moment.

[0112] Similarly, at the second moment, the calculated difference between the second maximum voltage value and the second minimum voltage value (the seventh voltage difference) is the maximum voltage difference of the battery pack at that moment. For the same battery cell, the difference between its voltage value and the second maximum voltage value (the sixth voltage difference) is calculated to obtain the voltage difference of the battery cell. The second voltage difference ratio is the ratio of the voltage difference of the battery cell to the maximum voltage difference of the battery pack at the second moment, which represents the relationship between the voltage of the battery cell at the second moment and the overall voltage distribution of the battery pack.

[0113] Optionally, in a specific embodiment of the present application, under charging conditions, two key charging points are first extracted: charge_id_1 and charge_id_2. charge_id_1 is the charging moment (i.e., the first moment) when the battery pack's charge level is less than 60% (SOC<60%) and the maximum voltage difference at this moment is greater than 30mV during the charging process. At this point, the voltage data of all cells are recorded, and the difference between the first voltage value (V_1_i) and the first minimum voltage value (minv_1) of each cell at the first moment is calculated (i.e., the fourth voltage difference, ΔV_1_i=V_1_i–minv_1), as well as the maximum voltage difference at the current moment (i.e., the fifth voltage difference, ΔV_1=maxv_1–minv_1). Similarly, charge_id_2 is the charging moment (i.e., the second moment) when the battery pack's charge level is greater than 90% (SOC>90%) and the maximum voltage difference at this moment is greater than 30mV during the charging process. At this point, the voltage data of all cells are also recorded, and the difference between the second voltage value (V_2_i) and the minimum voltage (minv_2) of each cell at the second moment (i.e., the sixth voltage difference, ΔV_2_i = V_2_i – minv_2) and the current maximum voltage difference (i.e., the seventh voltage difference, ΔV_2 = maxv_2 – minv_2) are calculated.

[0114] If the difference (ΔV_1_i) between the voltage of a certain cell at the moment of charge_id_1 and the minimum voltage is 0, it means that the target cell is the starting lowest voltage cell, and the target voltage difference ratio corresponding to the target cell can be calculated by the formula Cap_soh_index = (ΔV_2-ΔV_2_i) / ΔV_2, where the second value is ΔV_2-ΔV_2_i. If the difference (ΔV_2_i) between the voltage of a certain cell at the moment of charge_id_2 and the minimum voltage is 0, it means that the target cell is the terminal lowest voltage cell. At this time, it is assumed that there is no abnormal capacity attenuation and it is not calculated. Among them, the lowest voltage cell and the highest voltage cell refer to the cells with the minimum voltage value and the maximum voltage value, respectively, among the voltage values ​​of the cells in the battery pack at any moment.

[0115] Optionally, in the charging condition, (ΔV_1_i / ΔV_1) is the first pressure difference ratio, and (ΔV_2_i / ΔV_2) is the second pressure difference ratio.

[0116] In the discharging condition, the steps are similar to the charging condition. First, identify a complete discharging process, and extract two key discharging points: charge_id_3 and charge_id_4. charge_id_3 is the discharging time when the battery pack is greater than 90% (SOC>90%) and the maximum pressure difference at this time is greater than 30mV (i.e. the second time). At this point, record the voltage data of all cells at the second time, and calculate the difference between each cell voltage (V_3_i) and the maximum voltage (maxv_3) (ΔV_3_i=maxv_3-V_3_i), and the current maximum pressure difference (ΔV_3=maxv_3-minv_3). Similarly, charge_id_4 is the discharging time when the battery pack is less than 60% (SOC<60%) and the maximum pressure difference at this time is greater than 30mV, i.e. the first time. At this point, also record the voltage data of all cells at the first time, and calculate the difference between each cell voltage (V_4_i) and the maximum voltage (maxv_4) (ΔV_4_i=maxv_4-V_4_i), and the current maximum pressure difference (ΔV_4=maxv_4-minv_4).

[0117] If the ΔV_3_i of a cell at charge_id_3 is 0, it means that the target cell is the starting highest voltage monomer, and its target pressure difference ratio can be calculated by the formula Cap_soh_index=(ΔV_4-ΔV_4_i) / ΔV_4, where the third value is ΔV_4-ΔV_4_i. If the ΔV_4_i of a cell at charge_id_4 is 0, it means that the target cell is the end of discharging highest voltage monomer, and by default it does not exist capacity abnormal attenuation, and it is not calculated.

[0118] Optionally, in the discharging condition, (ΔV_3_i / ΔV_3) is the first pressure difference ratio, and (ΔV_4_i / ΔV_4) is the second pressure difference ratio.

[0119] Finally, by comparing the value of Cap_soh_index, the capacity abnormal attenuation of the cell can be quantitatively evaluated. When Cap_soh_index value is greater than or equal to 1, it is assumed that the target cell does not exist capacity abnormal attenuation; and when Cap_soh_index value is between 0 and 1, it is judged that the target cell exists capacity abnormal attenuation, the smaller the Cap_soh_index value, the greater the capacity attenuation degree of the corresponding target cell, and the more serious the short board.

[0120] In these optional embodiments, the voltage distribution characteristics of the battery pack are effectively evaluated by accurately capturing the voltage data of the battery pack to be tested at key moments in different power stages (low power and high power) in historical operating conditions. By calculating the voltage difference ratio between the maximum voltage value, the minimum voltage value and the target cell voltage value at the first moment (low power stage) and the second moment (high power stage), that is, the first voltage difference ratio and the second voltage difference ratio, the relative relationship between the voltage performance of the target cell in different power states and the overall voltage level of the battery pack can be deeply revealed. This evaluation method not only improves the accuracy of understanding the performance status of the battery pack, but also provides an important basis for health monitoring, fault diagnosis and capacity attenuation prediction of the battery pack, which helps to optimize battery management strategies, extend battery life, and ensure the safe and stable operation of the battery system.

[0121] In one embodiment, determining the initial battery capacity attenuation identification result corresponding to the target battery cell and the historical operating conditions based on the target voltage difference ratio includes:

[0122] determining a matching degree between the first relationship and the second relationship according to a relationship between the first pressure difference proportion and the second pressure difference proportion;

[0123] An initial battery capacity attenuation identification result corresponding to the target battery cell and the historical operating condition is determined according to the matching degree.

[0124] Optionally, in an embodiment of the present application, the degree of matching is determined by comparing the voltage difference ratios of the battery cells at the two charging points to determine whether they are consistent or similar. If the voltage difference ratios of the battery cells at the two charging points are not much different, it indicates that the voltage changes of the battery cells in the two stages are relatively consistent, which means that the capacity of the battery cells is relatively stable and there is no abnormal capacity decay. Conversely, if the voltage difference ratios differ significantly, it indicates that the capacity of the battery cells has changed significantly between the two stages and there is abnormal capacity decay.

[0125] Optionally, in a specific embodiment of the present application, under charging conditions, after obtaining the proportions of each voltage difference, the matching degree (Cap_soh_index) of the target battery cell can be calculated based on these voltage difference proportions. Cap_soh_index = (ΔV_1_i / ΔV_1) / (ΔV_2_i / ΔV_2) = (ΔV_1_iΔV_2) / (ΔV_1ΔV_2_i), where, under charging conditions, (ΔV_1_i / ΔV_1) is the first voltage difference proportion, and (ΔV_2_i / ΔV_2) is the second voltage difference proportion.

[0126] In the discharging condition, the steps are similar to the charging condition. The matching degree (Cap_soh_index) of the target cell is calculated according to the pressure difference ratio at the two moments. Cap_soh_index = (ΔV_3_i / ΔV_3) / (ΔV_4_i / ΔV_4) = (ΔV_3_i*ΔV_4) / (ΔV_3*ΔV_4_i), wherein, in the discharging condition, (ΔV_3_i / ΔV_3) is the first pressure difference ratio, and (ΔV_4_i / ΔV_4) is the second pressure difference ratio.

[0127] Finally, by comparing the value of Cap_soh_index, the capacity abnormal attenuation of the cell can be quantitatively evaluated. When the value of Cap_soh_index is greater than or equal to 1, it is determined that the target cell does not have capacity abnormal attenuation; when the value of Cap_soh_index is between 0 and 1, it is determined that the target cell has capacity abnormal attenuation, and the smaller the value of Cap_soh_index, the greater the capacity attenuation of the corresponding target cell, and the more serious the short board.

[0128] Optionally, in an optional implementation of the present application, the present application further introduces the time dimension, that is, the Cap_soh_index calculation results of the same single cell under different historical conditions in a certain period of time (such as a month, a quarter, etc.) are accumulated. At the same time, the number m of times that the cell triggers different conditions to calculate the capacity abnormal attenuation in this period of time is counted. This number reflects the frequency of the cell being detected to have a possible capacity abnormal attenuation problem under different conditions.

[0129] Finally, by comparing the accumulated Cap_soh_index value and the number m of times, the capacity abnormal attenuation of the target cell is determined, that is, the target battery capacity attenuation identification result. If the accumulated value is less than m, it is considered that the cell has a capacity abnormal attenuation fault, and the smaller the value, the closer to 0, the more serious the capacity abnormal attenuation, and vice versa, greater than m, it is considered that the target cell does not have capacity abnormal attenuation. This comprehensive judgment method not only considers the performance of the cell under different conditions, but also combines the time factor, so that the quantitative detection result of the capacity abnormal identification can be more reliably output, providing strong support for the maintenance and management of the battery pack.

[0130] Optionally, in the embodiment of the present application, the calculated Cap_soh_index can be directly applied to the judgment of the consistency of the battery pack capacity. Since the capacity attenuation of each cell has been quantitatively evaluated, the cell with faster capacity attenuation can be clearly identified by the value of Cap_soh_index, so as to judge the consistency level of the overall capacity of the battery pack. This is of great significance to maintain the performance stability and prolong the service life of the battery pack.

[0131] In a battery pack, because each cell experiences varying capacity degradation, balancing control is necessary to ensure a balanced voltage and capacity across the cells. The quantitative indicator Cap_soh_index provided in this application can accurately guide the timing and duration of balancing control, thereby maximizing the life of the cells while maintaining battery pack performance.

[0132] In these optional embodiments, the relationship between the first pressure difference ratio and the second pressure difference ratio, i.e., the degree of matching, is quantitatively analyzed to accurately determine the capacity decay of the target cell in the battery pack under test. This data analysis-based approach not only improves the accuracy and objectivity of the determination but also provides strong support for battery pack health management and maintenance.

[0133] In one embodiment, determining a target time corresponding to a historical operating condition includes:

[0134] When the historical operating condition is a constant current charging condition, obtaining a target charging stage in the constant current charging condition, wherein the target charging stage satisfies: a voltage change of one unit of charging power is greater than a preset change threshold;

[0135] Obtaining a first voltage difference corresponding to each moment in the target charging process; the first voltage difference corresponding to each moment is the voltage difference between the maximum voltage value and the minimum voltage value of the voltage values ​​of each battery cell at that moment;

[0136] The time corresponding to the first target voltage difference is determined as the target time; the first target voltage difference is the maximum value of the first voltage differences corresponding to each time.

[0137] Optionally, in a feasible implementation of the present application, first, a target charging stage in which the voltage change is greater than 10mv under a unit charging capacity (i.e., 1% SOC, State of Charge) is identified from a constant current charging condition. The constant current charging condition requires that the standard deviation of the current is less than 0.2. At the same time, the starting SOC of the charge is limited to no more than 60% SOC.

[0138] Next, in the target charging phase, a plurality of first voltage differences corresponding to each moment are further acquired. These first voltage differences refer to the difference between the maximum voltage value and the minimum voltage value among the voltage values ​​of the battery cells in the battery pack at that moment.

[0139] Then, the maximum value among these first voltage differences is found, namely the first target voltage difference, and the time corresponding to this difference is determined as the target time. During constant current charging, as the SOC increases, the voltage difference between battery cells generally increases gradually. When this difference reaches its maximum value, it often reflects the worst state of battery cell voltage consistency under the current operating conditions, and is therefore a key moment to assess whether the battery pack has abnormal capacity decay.

[0140] In these optional embodiments, by identifying the target charging stage during constant current charging where the voltage variation per unit of charge exceeds a preset threshold and obtaining the maximum voltage difference between cells at each moment in this stage, the moment when the battery pack's voltage inconsistency reaches its extreme value during charging can be accurately captured. Determining this moment as the target moment facilitates in-depth analysis of battery pack performance, timely identifying potential capacity decay anomalies, and improving the safety and reliability of the battery system.

[0141] In one embodiment, determining a target time corresponding to a historical operating condition includes:

[0142] Obtain the first and second stages of the historical operating conditions, wherein the first stage satisfies: the power of the battery pack to be tested is less than a first preset power, and the voltage difference between the maximum voltage value and the minimum voltage value of the voltage values ​​of each battery cell of the battery pack to be tested is greater than a target preset threshold; the second stage satisfies: the real-time power of the battery pack to be tested is greater than a second preset power, the voltage difference between the maximum voltage value and the minimum voltage value of the voltage values ​​of each battery cell of the battery pack to be tested is greater than the target preset threshold, and the first preset power is less than the second preset power;

[0143] Obtaining the second voltage difference corresponding to each moment in the first stage; the second voltage difference corresponding to each moment is the voltage difference between the maximum voltage value and the minimum voltage value of the voltage values ​​of each battery cell at that moment;

[0144] The moment corresponding to the second target voltage difference is determined as the first moment; the second target voltage difference is the maximum value of the second voltage differences corresponding to each moment;

[0145] Obtaining a third voltage difference corresponding to each moment in the second stage; the third voltage difference corresponding to each moment is the voltage difference between the maximum voltage value and the minimum voltage value of the voltage values ​​of each battery cell at that moment;

[0146] The time corresponding to the third target voltage difference is determined as the second time; the third target voltage difference is the maximum value of the third voltage differences corresponding to each time;

[0147] The target time includes a first time and a second time.

[0148] Optionally, in one specific implementation of the present application, the key information of two stages is first extracted from the historical working conditions. The first stage focuses on the period when the battery pack has a low power (less than a first preset power, such as 60% SOC) and the voltage difference between the cells is significant (the difference between the maximum voltage value and the minimum voltage value exceeds a target preset threshold, such as 30mV). In this stage, the voltage difference between the cells at each time (i.e., the second voltage difference) is continuously monitored and recorded. Then, the maximum value (i.e., the second target voltage difference) is found from these voltage differences, and the time corresponding to the maximum value is defined as the first time. The importance of the first time lies in that it identifies the worst case of cell voltage consistency in the low power state of the battery pack, which is crucial for evaluating the health status of the battery pack.

[0149] Similarly, the second stage focuses on the period when the battery pack has a high power (greater than a second preset power, such as 90% SOC) and the voltage difference between the cells is also significant. In this stage, the voltage difference between the cells (i.e., the third voltage difference) is also continuously monitored and recorded, and the maximum value (i.e., the third target voltage difference) is found, and the time corresponding to the maximum value is defined as the second time. The importance of the second time lies in that it reveals the worst case of cell voltage consistency in the high power state of the battery pack, which helps to further understand the performance changes of the battery pack.

[0150] It is worth noting that the setting of the first preset power and the second preset power is based on the in-depth understanding of the performance characteristics of the battery pack, aiming to ensure that the selected stage can fully reflect the health status of the battery pack. At the same time, the setting of the target preset threshold is also based on a large amount of experimental data and statistical analysis, to ensure that the significant changes in the voltage difference between the cells can be accurately captured.

[0151] In these optional embodiments, the target times corresponding to the historical working conditions, i.e., the first time and the second time, can be accurately determined. These two times not only represent the worst case of cell voltage consistency during the charging process of the battery pack, but also provide important reference for subsequent battery pack health status evaluation and maintenance decision-making, improving the overall performance and safety of the battery system.

[0152] It should be noted that the various optional implementations introduced in the embodiments of the present application can be combined with each other to implement, or can be implemented alone, and the embodiments of the present application do not limit this.

[0153] Figure 3 The structure schematic diagram of the battery capacity abnormal attenuation identification device provided by another embodiment of the present application is shown, and only the parts related to the embodiments of the present application are shown for convenience of description.

[0154] Referring to Figure 3 , the battery capacity abnormal attenuation identification device can include:

[0155] An acquisition module 301 is configured to acquire voltage data of n historical operating conditions of the battery pack to be tested, where n is a positive integer, the n historical operating conditions include at least one of a constant current charging condition, a non-constant current charging condition, and a discharge condition, and the voltage data of the historical operating conditions includes the voltage value of each cell in the battery pack to be tested under the historical operating conditions;

[0156] A first determining module 302 is configured to determine, for each of the n historical operating conditions, a target time corresponding to the historical operating condition;

[0157] A second determination module 303 is configured to determine an initial battery capacity decay identification result corresponding to the target cell and the historical operating condition based on a relationship between the voltage value of the target cell of the battery pack to be tested at the target time and a reference voltage value of the battery pack to be tested; the reference voltage value is the maximum voltage value or the minimum voltage value among the voltage values ​​of the battery pack to be tested at the target time;

[0158] The third determining module 304 is configured to determine a target battery capacity attenuation identification result of the target battery cell according to the initial battery capacity attenuation identification results of the target battery cell corresponding to the n historical operating conditions.

[0159] In one embodiment, the second determining module 303 may include:

[0160] A first acquisition submodule is configured to acquire a maximum voltage value and a minimum voltage value of the battery pack to be tested at the target time, and a target voltage value of the target cell at the target time;

[0161] A first determination submodule is configured to determine a target voltage difference ratio corresponding to the historical operating condition based on the maximum voltage value, the minimum voltage value, and the target voltage value; wherein the target voltage difference ratio represents the relationship between the voltage value of the target cell of the battery pack to be tested and the reference voltage value of the battery pack to be tested at the target moment;

[0162] The second determination submodule is used to determine the initial battery capacity attenuation identification result corresponding to the target battery cell and the historical operating conditions according to the target voltage difference ratio.

[0163] In one embodiment, when the historical operating condition is a constant current charging condition, the target battery cell is a fully charged cell of the battery pack to be tested in the last charging condition of the constant current charging condition; the first determination submodule may include:

[0164] a first determining unit, configured to determine a first voltage difference between a maximum voltage value and a minimum voltage value;

[0165] a second determining unit, configured to determine a second voltage difference between the target voltage value and the minimum voltage value;

[0166] The third determining unit is configured to determine a ratio of the second pressure difference to the first pressure difference as a target pressure difference ratio.

[0167] In one embodiment, the device for identifying abnormal battery capacity attenuation may further include:

[0168] a second acquisition module, configured to acquire the charging ampere-hours of the target battery cell between a third moment and a fourth moment; wherein, at the third moment, a maximum voltage value among the voltage values ​​of the battery cells of the battery pack to be tested is equal to the target voltage value; and at the fourth moment, a minimum voltage value among the voltage values ​​of the battery cells of the battery pack to be tested is equal to the target voltage value;

[0169] a fourth determining module, configured to determine a third voltage difference between the maximum voltage value and the target voltage value;

[0170] A fifth determination module is configured to determine a ratio of a first value to the first voltage difference as the attenuation capacity of the target battery cell; wherein the first value is the product of the charging ampere-hour and the third voltage difference.

[0171] In one embodiment, the target time includes a first time in a first stage of the historical operating condition and a second time in a second stage of the historical operating condition; in the first stage, the power of the battery pack to be tested is less than a first preset power, in the second stage, the power of the battery pack to be tested is greater than a second preset power, and the first preset power is less than the second preset power;

[0172] The maximum voltage value includes a first maximum voltage value of the battery pack to be tested at the first moment, and a second maximum voltage value of the battery pack to be tested at the second moment; the minimum voltage value includes a first minimum voltage value of the battery pack to be tested at the first moment, and a second minimum voltage value of the battery pack to be tested at the second moment; the target voltage value includes a first voltage value of the target battery cell at the first moment, and a second voltage value of the target battery cell at the second moment;

[0173] When the historical operating condition is a charging condition, the target cell is a cell other than the cell with the lowest voltage in the battery pack to be tested at the second moment; when the historical operating condition is a discharging condition, the target cell is a cell other than the cell with the highest voltage in the battery pack to be tested at the first moment; the first determination submodule may include:

[0174] a fourth determining unit, configured to determine a fourth voltage difference based on the first voltage value, the first minimum voltage value, and the first maximum voltage value; wherein, when the historical operating condition is a charging condition, the fourth voltage difference is a difference between the first voltage value and the first minimum voltage value; and when the historical operating condition is a discharging condition, the fourth voltage difference is a difference between the first maximum voltage value and the first voltage value;

[0175] a fifth determining unit, configured to determine a fifth voltage difference between the first maximum voltage value and the first minimum voltage value;

[0176] a sixth determining unit, configured to determine a sixth voltage difference based on the second voltage value, the second minimum voltage value, and the second maximum voltage value; wherein, when the historical operating condition is a charging condition, the sixth voltage difference is a difference between the second voltage value and the second minimum voltage value; and when the historical operating condition is a discharging condition, the sixth voltage difference is a difference between the second maximum voltage value and the second voltage value;

[0177] a seventh determining unit, configured to determine a seventh voltage difference between the second maximum voltage value and the second minimum voltage value;

[0178] An eighth determining unit is configured to determine a target pressure difference ratio corresponding to the historical operating condition based on the fourth pressure difference, the fifth pressure difference, the sixth pressure difference, and the seventh pressure difference.

[0179] In one embodiment, the eighth determining unit may include:

[0180] a first determining subunit, configured to, when the historical operating condition is a charging operating condition and the target battery cell is the lowest voltage cell of the battery pack to be tested at the first moment, determine a ratio of the second value to the seventh voltage difference as the target voltage difference ratio; wherein the second value is a difference between the seventh voltage difference and the sixth voltage difference;

[0181] a second determining subunit, configured to, when the historical operating condition is a discharge operating condition and the target battery cell is the highest voltage cell of the battery pack to be tested at the second moment, determine a ratio of a third value to the seventh voltage difference as the target voltage difference ratio; wherein the third value is a difference between the fifth voltage difference and the fourth voltage difference;

[0182] The third determination sub-unit is used to determine the ratio of the fourth pressure difference to the fifth pressure difference as the first pressure difference ratio when the target cell is the cell other than the lowest voltage cell and the highest voltage cell in the battery pack to be tested at the first moment and the second moment; and determine the ratio of the sixth pressure difference to the seventh pressure difference as the second pressure difference ratio; wherein the target pressure difference ratio includes the first pressure difference ratio and the second pressure difference ratio; the first pressure difference ratio represents the first relationship between the voltage value of the target cell of the battery pack to be tested at the first moment and the reference voltage value of the battery pack to be tested; the second pressure difference ratio represents the second relationship between the voltage value of the target cell of the battery pack to be tested at the second moment and the reference voltage value of the battery pack to be tested.

[0183] In one embodiment, the second determining submodule may include:

[0184] a ninth determining unit, configured to determine a matching degree between the first relationship and the second relationship according to a relationship between the first pressure difference ratio and the second pressure difference ratio;

[0185] A tenth determining unit is configured to determine, based on the matching degree, an initial battery capacity attenuation identification result corresponding to the target battery cell and the historical operating condition.

[0186] In one embodiment, the first determining module 302 may include:

[0187] The second acquisition submodule is configured to, when the historical operating condition is a constant current charging condition, acquire a target charging stage in the constant current charging condition, wherein the target charging stage satisfies: a voltage change of one unit of charging power is greater than a preset change threshold;

[0188] The third acquisition submodule is used to obtain the first voltage difference corresponding to each moment in the target charging process; the first voltage difference corresponding to each moment is the voltage difference between the maximum voltage value and the minimum voltage value of the voltage values ​​of each battery cell at that moment;

[0189] The third determining submodule is configured to determine the moment corresponding to the first target voltage difference as the target moment; the first target voltage difference is the maximum value of the first voltage differences corresponding to each moment.

[0190] In one embodiment, the first determining module 302 may include:

[0191] The fourth acquisition submodule is used to obtain the first stage and the second stage in the historical operating conditions, wherein the first stage satisfies: the power of the battery pack to be tested is less than the first preset power, and the voltage difference between the maximum voltage value and the minimum voltage value of the voltage values ​​of each battery cell of the battery pack to be tested is greater than the target preset threshold value; the second stage satisfies: the real-time power of the battery pack to be tested is greater than the second preset power, the voltage difference between the maximum voltage value and the minimum voltage value of the voltage values ​​of each battery cell of the battery pack to be tested is greater than the target preset threshold value, and the first preset power is less than the second preset power;

[0192] A fifth acquisition submodule is configured to acquire a second voltage difference corresponding to each moment in the first stage; the second voltage difference corresponding to each moment is a voltage difference between a maximum voltage value and a minimum voltage value among the voltage values ​​of each battery cell at that moment;

[0193] a fourth determining submodule, configured to determine the moment corresponding to the second target voltage difference as the first moment; the second target voltage difference being the maximum value of the second voltage differences corresponding to each moment;

[0194] a sixth acquisition submodule, configured to acquire a third voltage difference corresponding to each moment in the second stage; the third voltage difference corresponding to each moment being the voltage difference between the maximum voltage value and the minimum voltage value of the voltage values ​​of each battery cell at that moment;

[0195] a fifth determining submodule, configured to determine the moment corresponding to the third target voltage difference as the second moment; the third target voltage difference being the maximum value of the third voltage differences corresponding to each moment;

[0196] The target time includes a first time and a second time.

[0197] It should be noted that the information interaction, execution process, etc. between the above-mentioned devices / units are based on the same concept as the method embodiment of the present application, and are devices corresponding to the above-mentioned method. All implementation methods in the above-mentioned method embodiment are applicable to the embodiment of the device. Its specific functions and the technical effects brought about can be found in the method embodiment part, which will not be repeated here.

[0198] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0199] Figure 4 A schematic diagram of the hardware structure of an electronic device provided in an embodiment of the present application is shown.

[0200] The device may include a processor 401 and a memory 402 storing program instructions.

[0201] When the processor 401 executes the program, the steps in any of the above method embodiments are implemented.

[0202] For example, the program can be divided into one or more modules / units, one or more modules / units are stored in the memory 402 and executed by the processor 401 to complete the present application. One or more modules / units can be a series of program instruction segments that can perform specific functions, and the instruction segments are used to describe the execution process of the program in the device.

[0203] Specifically, the processor 401 may include a central processing unit (CPU), or an application-specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present application.

[0204] Memory 402 may include a large capacity memory for data or instructions. By way of example and not limitation, memory 402 may include a hard disk drive (HDD), a floppy disk drive, a flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus (USB) drive, or a combination of two or more of these. Where appropriate, memory 402 may include removable or non-removable (or fixed) media. Where appropriate, memory 402 may be inside or outside the integrated gateway disaster recovery device. In a specific embodiment, memory 402 is a non-volatile solid-state memory.

[0205] The memory may include read-only memory (ROM), random access memory (RAM), magnetic disk storage media devices, optical storage media devices, flash memory devices, electrical, optical or other physical / tangible memory storage devices. Thus, generally, the memory includes one or more tangible (non-transitory) readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the method according to an aspect of the present disclosure.

[0206] The processor 401 implements any one of the methods in the above embodiments by reading and executing program instructions stored in the memory 402 .

[0207] In one example, the electronic device may further include a communication interface 403 and a bus 410. The processor 401, the memory 402, and the communication interface 403 are connected via the bus 410 and communicate with each other.

[0208] The communication interface 403 is mainly used to implement communication between various modules, devices, units and / or equipment in the embodiments of the present application.

[0209] Bus 410 includes hardware, software or both, and the components of online data flow metering equipment are coupled to each other. For example, but not limitation, bus may include accelerated graphics port (AGP) or other graphics bus, enhanced industry standard architecture (EISA) bus, front side bus (FSB), hypertransport (HT) interconnection, industry standard architecture (ISA) bus, infinite bandwidth interconnection, low pin count (LPC) bus, memory bus, micro channel architecture (MCA) bus, peripheral component interconnection (PCI) bus, PCI-Express (PCI-X) bus, serial advanced technology attachment (SATA) bus, video electronics standard association local (VLB) bus or other suitable bus or two or more of these combinations. In appropriate cases, bus 410 may include one or more buses. Although the present application embodiment describes and shows a specific bus, the application considers any suitable bus or interconnection.

[0210] In addition, in combination with the methods in the above embodiments, embodiments of the present application may provide a storage medium for implementation. The storage medium stores program instructions; when the program instructions are executed by a processor, any one of the methods in the above embodiments is implemented.

[0211] An embodiment of the present application further provides a chip, which includes a processor and a communication interface, the communication interface and the processor are coupled, and the processor is used to run programs or instructions to implement the various processes of the above-mentioned method embodiment and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0212] It should be understood that the chip mentioned in the embodiments of the present application can also be called a system-level chip, a system chip, a chip system or a system-on-chip chip, etc.

[0213] An embodiment of the present application provides a computer program product, which is stored in a storage medium. The program product is executed by at least one processor to implement the various processes of the above-mentioned method embodiment and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0214] It should be understood that the present application is not limited to the specific configurations and processes described above and illustrated in the figures. For the sake of brevity, a detailed description of known methods is omitted here. In the above embodiments, several specific steps are described and illustrated as examples. However, the method process of the present application is not limited to the specific steps described and illustrated. Those skilled in the art can make various changes, modifications, and additions, or change the order of the steps after understanding the spirit of the present application.

[0215] The functional modules shown in the above block diagram can be implemented as hardware, software, firmware or a combination thereof. When implemented in hardware, it can be, for example, an electronic circuit, an application specific integrated circuit (ASIC), suitable firmware, a plug-in unit, a function card or the like. When implemented in software, the elements of the present application are programs or code segments that are used to perform the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted on a transmission medium or a communication link by a data signal carried in a carrier wave. "Machine-readable medium" can include any medium that can store or transmit information. The example of a machine-readable medium includes an electronic circuit, a semiconductor memory device, a ROM, a flash memory, an erasable ROM (EROM), a floppy disk, a CD-ROM, an optical disk, a hard disk, an optical fiber medium, a radio frequency (RF) link, or the like. The code segment can be downloaded via a computer grid such as the Internet, an intranet, etc.

[0216] It should also be noted that the exemplary embodiments mentioned in this application describe some methods or systems based on a series of steps or devices. However, this application is not limited to the order of the above steps. In other words, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0217] Aspects of the present disclosure have been described above with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and program products according to the embodiments of the present disclosure. It should be understood that each box in the flowchart and / or block diagram and the combination of each box in the flowchart and / or block diagram can be implemented by computer program instructions. These program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer or other programmable data processing device to produce a machine so that these instructions executed via the processor of the computer or other programmable data processing device enable the implementation of the function / action specified in one or more boxes of the flowchart and / or block diagram. This processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor or a field programmable logic circuit. It is also understood that each box in the block diagram and / or the flowchart and the combination of the boxes in the block diagram and / or the flowchart can also be implemented by the dedicated hardware that performs the specified function or action, or can be implemented by the combination of dedicated hardware and computer instructions.

[0218] The above is only a specific implementation method of the present application. Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the systems, modules and units described above can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here. It should be understood that the scope of protection of the present application is not limited to this. Any technician familiar with this technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in this application, and these modifications or replacements should be included in the scope of protection of this application.

Claims

1. A method for identifying abnormal battery capacity attenuation, characterized in that: The method comprises: Obtain voltage data of n historical operating conditions of the battery pack to be tested, where n is a positive integer, the n historical operating conditions include at least one of a constant current charging condition, a non-constant current charging condition, and a discharging condition, and the voltage data of the historical operating conditions include the voltage value of each cell in the battery pack to be tested under the historical operating conditions; For each of the n historical operating conditions, determining a target time corresponding to the historical operating condition; Determining an initial battery capacity attenuation identification result corresponding to the target cell and the historical operating condition based on a relationship between a voltage value of a target cell of the battery pack to be tested at the target time and a reference voltage value of the battery pack to be tested; the reference voltage value is a maximum voltage value or a minimum voltage value of the battery pack to be tested at the target time; Determining a target battery capacity attenuation identification result of the target battery cell according to the initial battery capacity attenuation identification results of the target battery cell corresponding to the n historical operating conditions; The determining, based on a relationship between a voltage value of a target cell of the battery pack to be tested and a reference voltage value of the battery pack to be tested at the target time, an initial battery capacity attenuation identification result corresponding to the target cell and the historical operating condition includes: Obtaining the maximum voltage value and the minimum voltage value of the battery pack to be tested at the target time, and the target voltage value of the target battery cell at the target time; Determine a target voltage difference ratio corresponding to the historical operating condition according to the maximum voltage value, the minimum voltage value, and the target voltage value; wherein the target voltage difference ratio represents a relationship between the voltage value of the target cell of the battery pack to be tested and the reference voltage value of the battery pack to be tested at the target moment; An initial battery capacity attenuation identification result corresponding to the target battery cell and the historical operating condition is determined according to the target voltage difference ratio.

2. The method according to claim 1, characterized in that When the historical operating condition is the constant current charging condition, the target battery cell is a fully charged cell of the battery pack to be tested in the last charging condition of the constant current charging condition; The determining, according to the maximum voltage value, the minimum voltage value, and the target voltage value, a target pressure difference ratio corresponding to the historical operating condition includes: determining a first voltage difference between the maximum voltage value and the minimum voltage value; determining a second voltage difference between the target voltage value and the minimum voltage value; The ratio of the second pressure difference to the first pressure difference is determined as the target pressure difference ratio.

3. The method according to claim 2, characterized in that After determining that the initial battery capacity decay identification result corresponding to the target battery cell and the historical operating condition is that the target battery cell has a capacity decay abnormality, the method further includes: Obtaining the charging ampere-hours of the target battery cell between a third moment and a fourth moment; wherein, at the third moment, the maximum voltage value among the voltage values ​​of the battery cells of the battery pack to be tested is equal to the target voltage value; and at the fourth moment, the minimum voltage value among the voltage values ​​of the battery cells of the battery pack to be tested is equal to the target voltage value; determining a third voltage difference between the maximum voltage value and the target voltage value; The ratio of the first value to the first voltage difference is determined as the attenuation capacity of the target battery cell; wherein the first value is the product of the charging ampere-hour and the third voltage difference.

4. The method according to claim 1, wherein The target time includes a first time in a first stage of the historical operating condition and a second time in a second stage of the historical operating condition; in the first stage, the power of the battery pack to be tested is less than a first preset power, in the second stage, the power of the battery pack to be tested is greater than a second preset power, and the first preset power is less than the second preset power; The maximum voltage value includes a first maximum voltage value of the battery pack to be tested at the first moment, and a second maximum voltage value of the battery pack to be tested at the second moment; The minimum voltage value includes a first minimum voltage value of the battery pack to be tested at the first moment, and a second minimum voltage value of the battery pack to be tested at the second moment; the target voltage value includes a first voltage value of the target battery cell at the first moment, and a second voltage value of the target battery cell at the second moment; When the historical operating condition is a charging condition, the target cell is the cell other than the cell with the lowest voltage in the battery pack to be tested at the second moment; when the historical operating condition is a discharging condition, the target cell is the cell other than the cell with the highest voltage in the battery pack to be tested at the first moment; The determining, according to the maximum voltage value, the minimum voltage value, and the target voltage value, a target pressure difference ratio corresponding to the historical operating condition includes: determining a fourth voltage difference based on the first voltage value, the first minimum voltage value, and the first maximum voltage value; wherein, when the historical operating condition is a charging condition, the fourth voltage difference is a difference between the first voltage value and the first minimum voltage value; and when the historical operating condition is a discharging condition, the fourth voltage difference is a difference between the first maximum voltage value and the first voltage value; determining a fifth voltage difference between the first maximum voltage value and the first minimum voltage value; determining a sixth voltage difference based on the second voltage value, the second minimum voltage value, and the second maximum voltage value; wherein, when the historical operating condition is a charging condition, the sixth voltage difference is a difference between the second voltage value and the second minimum voltage value; and when the historical operating condition is a discharging condition, the sixth voltage difference is a difference between the second maximum voltage value and the second voltage value; determining a seventh voltage difference between the second maximum voltage value and the second minimum voltage value; A target pressure difference ratio corresponding to the historical operating condition is determined according to the fourth pressure difference, the fifth pressure difference, the sixth pressure difference, and the seventh pressure difference.

5. The method according to claim 4, characterized in that The determining, based on the fourth pressure difference, the fifth pressure difference, the sixth pressure difference, and the seventh pressure difference, of a target pressure difference ratio corresponding to the historical operating condition includes: When the historical operating condition is a charging operating condition and the target battery cell is the lowest voltage cell of the battery pack to be tested at the first moment, a ratio of the second value to the seventh voltage difference is determined as the target voltage difference ratio; wherein the second value is a difference between the seventh voltage difference and the sixth voltage difference; When the historical operating condition is a discharge operating condition and the target battery cell is the highest voltage cell of the battery pack to be tested at the second moment, a ratio of the third value to the seventh voltage difference is determined as the target voltage difference ratio; wherein the third value is a difference between the fifth pressure difference and the fourth pressure difference; When the target cell is a cell other than the lowest voltage cell and the highest voltage cell in the battery pack to be tested at the first moment and the second moment, the ratio of the fourth pressure difference to the fifth pressure difference is determined as the first pressure difference ratio; the ratio of the sixth pressure difference to the seventh pressure difference is determined as the second pressure difference ratio; wherein, the target pressure difference ratio includes the first pressure difference ratio and the second pressure difference ratio; the first pressure difference ratio represents the first relationship between the voltage value of the target cell of the battery pack to be tested at the first moment and the reference voltage value of the battery pack to be tested; the second pressure difference ratio represents the second relationship between the voltage value of the target cell of the battery pack to be tested at the second moment and the reference voltage value of the battery pack to be tested.

6. The method according to claim 5, characterized in that The determining, based on the target voltage difference ratio, an initial battery capacity attenuation identification result corresponding to the target battery cell and the historical operating condition includes: determining a matching degree between the first relationship and the second relationship according to a relationship between the first pressure difference proportion and the second pressure difference proportion; An initial battery capacity attenuation identification result corresponding to the target battery cell and the historical operating condition is determined according to the matching degree.

7. The method according to claim 1, characterized in that The determining of the target time corresponding to the historical operating condition includes: When the historical operating condition is the constant current charging operating condition, obtaining a target charging stage in the constant current charging operating condition, wherein the target charging stage satisfies: a voltage change of one unit of charging power is greater than a preset change threshold; Obtaining a first voltage difference corresponding to each moment in the target charging process; the first voltage difference corresponding to each moment is a voltage difference between a maximum voltage value and a minimum voltage value among the voltage values ​​of each battery cell at that moment; The time corresponding to the first target voltage difference is determined as the target time; the first target voltage difference is the maximum value of the first voltage differences corresponding to the various times.

8. The method according to claim 1, characterized in that The determining of the target time corresponding to the historical operating condition includes: Obtaining the first and second stages of the historical operating conditions, wherein the first stage satisfies: the power of the battery pack to be tested is less than a first preset power, and the voltage difference between the maximum voltage value and the minimum voltage value of the voltage values ​​of each battery cell of the battery pack to be tested is greater than a target preset threshold; the second stage satisfies: the real-time power of the battery pack to be tested is greater than a second preset power, the voltage difference between the maximum voltage value and the minimum voltage value of the voltage values ​​of each battery cell of the battery pack to be tested is greater than the target preset threshold, and the first preset power is less than the second preset power; Obtaining a second voltage difference corresponding to each moment in the first stage; the second voltage difference corresponding to each moment is a voltage difference between a maximum voltage value and a minimum voltage value among the voltage values ​​of each battery cell at the moment; Determine the moment corresponding to the second target voltage difference as the first moment; the second target voltage difference is the maximum value of the second voltage differences corresponding to the moments; Obtaining a third voltage difference corresponding to each moment in the second stage; the third voltage difference corresponding to each moment is a voltage difference between a maximum voltage value and a minimum voltage value among the voltage values ​​of each battery cell at the moment; Determine the moment corresponding to the third target voltage difference as the second moment; the third target voltage difference is the maximum value of the third voltage differences corresponding to the moments; The target time includes the first time and the second time.

9. An electronic device, characterized in that: The device includes: a processor and a memory storing computer program instructions; When the processor executes the computer program instructions, the method for identifying abnormal battery capacity attenuation according to any one of claims 1 to 8 is implemented.

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