Methods, systems, media, and program products for obtaining a decay acceleration coefficient for a battery cell

Abstract

The application provides a method, system, medium and program product for obtaining an attenuation acceleration coefficient of a battery cell, and relates to the field of batteries. The method comprises the following steps: determining a first correspondence relationship between a leakage current of the battery cell and a detection time under a plurality of test values of a same test parameter; determining a detection time corresponding to a stable state of the leakage current based on the first correspondence relationship; extracting the leakage current of the battery cell corresponding to the plurality of test values at the detection time corresponding to the stable state of the leakage current to construct a second correspondence relationship between the leakage current of the battery cell and the test parameter; and determining the attenuation acceleration coefficient based on the second correspondence relationship. According to the method, the attenuation acceleration coefficient of the battery cell can be determined without long-period data monitoring and complex data calculation, so that the efficiency and reliability of obtaining the attenuation acceleration coefficient are improved, and the battery life can be quickly and accurately predicted subsequently.

Description

Technical Field

[0001] This application relates to the field of batteries, and more particularly to a method, system, medium, and process product for obtaining the degradation acceleration coefficient of a battery cell. Background Technology

[0002] In order to establish cell life degradation equations under different operating conditions, long-term data is needed to determine reliable cell degradation acceleration coefficients when conducting battery life assessment.

[0003] The above statements are for the purpose of providing background information in relation to this application only and do not necessarily constitute prior art. Summary of the Invention

[0004] One technical problem this disclosure aims to solve is to provide a method, system, medium, and program product for obtaining the degradation acceleration coefficient of a battery cell, which can improve the efficiency of obtaining the degradation acceleration coefficient of a battery cell.

[0005] According to one aspect of this disclosure, a method for obtaining the degradation acceleration coefficient of a battery cell is proposed, comprising: determining a first correspondence between the leakage current of the battery cell and the detection time under multiple test values ​​of the same test parameter; determining the detection time corresponding to the stable state of the leakage current based on the first correspondence, wherein the stable state of the leakage current includes a difference in leakage current between adjacent times being less than a threshold; extracting the leakage current of the battery cell corresponding to the multiple test values ​​under the detection time corresponding to the stable state of the leakage current to construct a second correspondence between the leakage current of the battery cell and the test parameter; and determining the degradation acceleration coefficient based on the second correspondence.

[0006] In the technical solution of this application embodiment, the leakage current principle of the battery cell is utilized to first establish a first correspondence between leakage current and detection time, and extract the leakage current of the battery cell corresponding to multiple test values ​​at the detection time corresponding to the stable state of leakage current. This enables the construction of a second correspondence between leakage current and test parameters, thereby determining the attenuation acceleration coefficient. The attenuation acceleration coefficient of the battery cell can be determined without long-term data monitoring or complex data calculation, thereby improving the efficiency and reliability of obtaining the attenuation acceleration coefficient and facilitating subsequent rapid and accurate prediction of battery life.

[0007] In some embodiments, the test parameters include the test temperature, the second correspondence includes a second correspondence between the logarithm of the leakage current and the reciprocal of the test temperature, and the degradation acceleration coefficient includes a temperature acceleration coefficient. In this embodiment, by acquiring data on the change of cell leakage current over time at different temperatures, a second correspondence between cell leakage current and temperature is established, thereby enabling the rapid acquisition of the temperature acceleration coefficient. This provides important parameters for the subsequent construction of battery life models, thus improving the accuracy of battery life prediction.

[0008] In some embodiments, the second correspondence is represented by a first fitted straight line in a first coordinate system. Constructing the second correspondence between the leakage current of the battery cell and the test parameters includes: constructing a first coordinate system with the logarithm of the leakage current as the ordinate and the reciprocal of the test temperature as the abscissa; in the first coordinate system, linearly fitting the logarithms of the leakage current of the battery cell corresponding to the reciprocals of multiple test temperatures at the detection time corresponding to the stable state of the leakage current to obtain the first fitted straight line. Representing the second correspondence between leakage current and temperature using a fitted straight line in the coordinate system facilitates the subsequent intuitive and rapid determination of the temperature acceleration factor.

[0009] In some embodiments, determining the attenuation acceleration coefficient based on the second correspondence includes: determining the slope corresponding to the first fitted straight line as the temperature acceleration coefficient. In this embodiment, after obtaining a fitted straight line representing the correspondence between leakage current and temperature through linear fitting, the temperature acceleration coefficient can be determined by calculating the slope of the fitted straight line. The calculation process is simple and does not require a large amount of data, thus improving the efficiency of determining the temperature acceleration coefficient.

[0010] In some embodiments, the temperature boundary of the battery cell is determined based on discrete points in the first fitted straight line. Rapidly determining the temperature boundary of the battery cell reduces safety risks and prevents thermal runaway, providing support for ensuring safe, efficient, and long-life operation of the battery cell. It also serves as a fundamental basis for battery design, usage, and management system development.

[0011] In some embodiments, the test parameters include a test state of charge (SOC), the second correspondence includes a second correspondence between the leakage current and the test SOC, and the degradation acceleration factor includes a SOC acceleration factor. In this embodiment, by acquiring data on the leakage current of the battery cell over time at different SOCs, a second correspondence between the cell's leakage current and SOC is established, thereby enabling the rapid acquisition of the SOC acceleration factor. This provides important parameters for the subsequent construction of the battery life model, thereby improving the accuracy of battery life prediction.

[0012] In some embodiments, the second correspondence is represented by a second fitted straight line in a second coordinate system. Constructing the second correspondence between the cell's leakage current and test parameters includes: constructing a second coordinate system with the leakage current as the ordinate and the test state of charge as the abscissa; in the second coordinate system, linearly fitting the leakage current of the cell corresponding to multiple test states of charge at the detection time corresponding to the stable state of the leakage current to obtain the second fitted straight line. Representing the second correspondence between leakage current and SOC using a fitted straight line in the coordinate system facilitates the rapid and intuitive determination of the SOC acceleration factor.

[0013] In some embodiments, determining the attenuation acceleration factor based on the second correspondence includes: determining the slope corresponding to the second fitted straight line as the state-of-charge acceleration factor. In this embodiment, after obtaining a fitted straight line representing the correspondence between leakage current and SOC through linear fitting, the SOC acceleration factor can be determined by calculating the slope of the fitted straight line. The calculation process is simple and does not require a large amount of data, thus improving the efficiency of determining the SOC acceleration factor.

[0014] In some embodiments, the leakage current is determined by compensating for the self-discharge current of the battery cell using a constant voltage method. By compensating for the self-discharge current of the battery cell using a constant voltage method, the compensated current should be equal to the self-discharge current of the battery cell. Therefore, the leakage current of the battery cell can be quickly obtained, facilitating the subsequent determination of the battery cell degradation acceleration factor.

[0015] According to a second aspect of this disclosure, a system for obtaining the degradation acceleration coefficient of a battery cell is also proposed, comprising: a first determining module configured to determine a first correspondence between the leakage current of the battery cell and the detection time under multiple test values ​​of the same test parameter; a time determining module configured to determine a detection time corresponding to a stable leakage current state based on the first correspondence, wherein the stable leakage current state includes a leakage current difference between adjacent times being less than a threshold; a second determining module configured to extract the leakage current of the battery cell corresponding to the multiple test values ​​under the detection time corresponding to the stable leakage current state, to construct a second correspondence between the leakage current of the battery cell and the test parameter; and a coefficient determining module configured to determine a degradation acceleration coefficient based on the second correspondence.

[0016] In the technical solution of this application embodiment, the leakage current principle of the battery cell is utilized to first establish a first correspondence between leakage current and detection time, and extract the leakage current of the battery cell corresponding to multiple test values ​​at the detection time corresponding to the stable state of leakage current. This enables the construction of a second correspondence between leakage current and test parameters, thereby determining the attenuation acceleration coefficient. The attenuation acceleration coefficient of the battery cell can be determined without long-term data monitoring or complex data calculation, thereby improving the efficiency and reliability of obtaining the attenuation acceleration coefficient and facilitating subsequent rapid and accurate prediction of battery life.

[0017] According to a third aspect of this disclosure, a system for obtaining the degradation acceleration factor of a battery cell is also proposed, comprising: a processor; and a memory coupled to the processor for storing instructions, which, when executed by the processor, cause the processor to perform the method for obtaining the degradation acceleration factor of a battery cell as described above.

[0018] According to a fourth aspect of this disclosure, a computer-readable storage medium is also provided, on which computer instructions are stored, which, when executed by a processor, implement the above-described method for obtaining the cell's degradation acceleration factor.

[0019] According to a fifth aspect of this disclosure, a computer program product is also provided, comprising: computer instructions that, when executed by a processor, implement the above-described method for obtaining the cell attenuation acceleration coefficient.

[0020] Other features and advantages of this disclosure will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of a method for obtaining the degradation acceleration factor of a battery cell according to one or more embodiments;

[0023] Figure 2 This is a schematic diagram of a method for obtaining the temperature acceleration coefficient of a battery cell according to one or more embodiments;

[0024] Figure 3 A schematic diagram illustrating the first correspondence between leakage current and detection time at different temperatures according to one or more embodiments;

[0025] Figure 4 This is a schematic diagram illustrating a second correspondence between the logarithm of the leakage current and the reciprocal of the test temperature according to one or more embodiments.

[0026] Figure 5 This is a schematic diagram of a method for obtaining the SOC acceleration factor of a battery cell according to one or more embodiments;

[0027] Figure 6 A schematic diagram illustrating the first correspondence between leakage current and detection time under different SOCs according to one or more embodiments;

[0028] Figure 7 This is a schematic diagram illustrating a second correspondence between leakage current and test SOC according to one or more embodiments;

[0029] Figure 8 This is a schematic diagram of a system for obtaining the cell degradation acceleration coefficient according to one or more embodiments. Figure 1 ;

[0030] Figure 9 This is a schematic diagram of a system for obtaining the cell degradation acceleration coefficient according to one or more embodiments. Figure 2 ;

[0031] Figure 10 This is a schematic diagram of a system for obtaining the cell degradation acceleration coefficient according to one or more embodiments. Figure 3 . Detailed Implementation

[0032] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of this application by way of example, but should not be used to limit the scope of this application, that is, this application is not limited to the described embodiments.

[0033] In the description of this application, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationships, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. "Vertical" is not vertical in the strict sense, but within the allowable tolerance range. "Parallel" is not parallel in the strict sense, but within the allowable tolerance range.

[0034] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0035] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this disclosure or its application or use.

[0036] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0037] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0038] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0039] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0040] With the increasing demand for battery cell life assessment, there is a need to develop rapid life assessment methods. Currently, the reliability of key parameters in lifespan models and the data processing methods are closely related to the length of the test data. Related technologies require acquiring test data under different parameters over a long period, followed by complex data processing to determine the cell's degradation acceleration factor. If the data acquisition time is short, the data length directly affects the reliability of the fitting results. In situations requiring rapid and accurate prediction of battery life, this testing method, characterized by difficult data acquisition, long testing cycles, and high costs, clearly needs improvement.

[0041] This disclosure provides a scheme for obtaining the cell degradation acceleration coefficient, which can improve the efficiency and accuracy of obtaining the cell degradation acceleration coefficient, thereby facilitating subsequent rapid and accurate prediction of battery life. The scheme of this disclosure will now be described in conjunction with the accompanying drawings.

[0042] Figure 1 This is a schematic diagram of a method for obtaining the degradation acceleration coefficient of a battery cell according to one or more embodiments, which includes steps S1-S4.

[0043] In step S1, the first correspondence between the leakage current of the battery cell and the detection time is determined under multiple test values ​​of the same test parameter.

[0044] The test parameters are those related to cell degradation, such as test temperature, test SOC (State of Charge), test humidity, etc. This embodiment creates multiple test environments to obtain data on the cell's leakage current change over time. The detection time is, for example, in days, such as 10 days; the sampling interval is, for example, in seconds, such as 10 seconds. Those skilled in the art should understand that the units of days and seconds used here are merely examples, and the sampling frequency and period can be set according to actual conditions.

[0045] During battery storage, capacity decay manifests as battery self-discharge. In this embodiment, the cell's decay acceleration factor is calculated using the cell's leakage current.

[0046] The cell is, for example, a conventional laminated cell or a pouch cell.

[0047] For ease of observation, this first correspondence is displayed, for example, using a coordinate system. Those skilled in the art will understand that the obtained data can also be recorded in tables or similar formats.

[0048] In step S2, based on the first correspondence, the detection time corresponding to the stable state of leakage current is determined.

[0049] In some embodiments, by examining the relationship between the cell's leakage current and the detection time, it can be observed that the cell's leakage current will stabilize after a certain period of time. Subsequently, to determine the correspondence between the leakage current and the test parameters, it is necessary to determine when the cell's leakage current reaches a stable state.

[0050] In step S3, the leakage current of the battery cell corresponding to multiple test values ​​at the detection time corresponding to the stable state of leakage current is extracted to construct a second correspondence between the leakage current of the battery cell and the test parameters.

[0051] For ease of observation, this second correspondence is displayed, for example, using a coordinate system. Those skilled in the art will understand that the obtained data can also be recorded in tables or similar formats.

[0052] In step S4, the attenuation acceleration coefficient is determined based on the second correspondence.

[0053] In this embodiment, by utilizing the leakage current principle of the battery cell, a first correspondence between leakage current and detection time is first established. Then, the leakage current of the battery cell corresponding to multiple test values ​​is extracted at the detection time corresponding to the stable state of leakage current. This enables the construction of a second correspondence between leakage current and test parameters, thereby determining the degradation acceleration coefficient. The degradation acceleration coefficient of the battery cell can be determined without long-term data monitoring or complex data calculations, thus improving the efficiency and reliability of obtaining the degradation acceleration coefficient and facilitating rapid and accurate prediction of battery life.

[0054] In some embodiments, the leakage current is determined by compensating for the self-discharge current of the battery cell using a constant voltage method.

[0055] For example, when a battery cell is not in use, the internal current will naturally leak out, which is called self-discharge current. The self-discharge current of the battery cell can be compensated by constant voltage. The compensation current should be equal to the self-discharge current of the battery cell. Therefore, the leakage current of the battery cell can be obtained quickly, which is convenient for determining the subsequent battery cell degradation acceleration coefficient.

[0056] In some embodiments, the test parameters include the test temperature, the second correspondence includes a second correspondence between the logarithm of the leakage current and the reciprocal of the test temperature, and the attenuation acceleration factor includes a temperature acceleration factor.

[0057] For example, a first correspondence between the leakage current of the battery cell and the detection time is obtained at multiple test temperatures; based on the first correspondence, the detection time corresponding to the steady state of the leakage current is determined; the leakage current of the battery cell at multiple test temperatures at the detection time corresponding to the steady state of the leakage current is extracted to construct a second correspondence between the leakage current of the battery cell and the test temperature; based on the second correspondence, the temperature acceleration coefficient is determined.

[0058] In this embodiment, by acquiring data on the change of cell leakage current over time at different temperatures, a second correspondence between cell leakage current and temperature is established, thereby enabling the rapid acquisition of the temperature acceleration coefficient. This provides important parameters for the subsequent construction of the battery life model, thereby improving the accuracy of battery life prediction.

[0059] In some embodiments, the second correspondence is represented by a first fitted straight line in the first coordinate system. Constructing the second correspondence between the leakage current of the battery cell and the test parameters includes: constructing a first coordinate system with the logarithm of the leakage current as the vertical axis and the reciprocal of the test temperature as the horizontal axis; in the first coordinate system, linearly fitting the logarithm of the leakage current of the battery cell corresponding to the reciprocal of multiple test temperatures at the detection time corresponding to the stable state of the leakage current to obtain the first fitted straight line.

[0060] For example, when the leakage current of the battery cell is in a stable state, after obtaining multiple sets of leakage current data at different temperatures, a straight line is plotted in a first coordinate system with the logarithm of the leakage current as the ordinate and the reciprocal of the test temperature as the abscissa. This straight line represents the second correspondence between leakage current and temperature. Using the fitted straight line in the coordinate system to represent the second correspondence between leakage current and temperature facilitates the subsequent intuitive and rapid determination of the temperature acceleration factor.

[0061] In some embodiments, determining the attenuation acceleration coefficient based on the second correspondence includes: determining the slope corresponding to the first fitted straight line as the temperature acceleration coefficient.

[0062] For example, the temperature acceleration coefficient satisfies the Arrhenius equation: k = A * e^(-Ea / RT), where k represents the reaction rate and also the leakage current magnitude; A is the frequency factor; R is the molar gas constant, a known quantity; T is the thermodynamic temperature; and Ea is the activation energy. In leakage current testing, taking the logarithm of both sides of the Arrhenius equation yields lnk = lnA - Ea / (R*T). This can be plotted as a straight line in the first coordinate system, where the slope is -Ea / R and the intercept is lnA; -Ea / R represents the temperature acceleration coefficient.

[0063] In this embodiment, after obtaining a fitted straight line representing the relationship between leakage current and temperature through linear fitting, the temperature acceleration coefficient can be determined by calculating the slope of the fitted straight line. The calculation process is simple and does not require a large amount of data, thus improving the efficiency of determining the temperature acceleration coefficient.

[0064] Figure 2 This is a schematic diagram of a method for obtaining the temperature acceleration coefficient of a battery cell according to one or more embodiments, which includes steps S11-S41.

[0065] In step S11, the first correspondence between the leakage current of the battery cell and the detection time is obtained under multiple test temperatures.

[0066] For example, taking LEP cells as an example, the cell is adjusted to near a specified voltage value, left at room temperature for one day to depolarize, and then subjected to constant voltage testing. The constant voltage test temperature matrix and sample number are shown in Table 1 below:

[0067] Table 1 shows the constant pressure test temperature matrix and the number of samples.

[0068]

[0069] The room temperature is, for example, a constant temperature laboratory at 25°C, and the test temperatures include, for example, 25°C, 45°C, 60°C and 70°C, with 3 samples under each condition.

[0070] Before testing, prepare the testing equipment, which includes a self-discharge tester and a standard high and low temperature oven. Group the cells under test by temperature and by state of charge (SOC) and place them in the high and low temperature oven. After connecting the cells to the self-discharge tester, adjust the oven temperature to the four temperatures listed in the table, ready for constant voltage leakage current testing. Place the cells under test in the high and low temperature oven for 2 hours to allow them to reach a stable state at the specified temperature. Then, start the constant voltage test, with a sampling interval of, for example, 10 seconds, and a test cycle of, for example, 10 days, to obtain continuous leakage current data under constant voltage conditions.

[0071] By using an external constant voltage source, the energy loss caused by the self-discharge of the battery cell is compensated in real time, so that the battery cell voltage remains constant. At this time, the externally input compensation current is the self-discharge current of the battery cell, which is also called the leakage current.

[0072] like Figure 3 As shown, Figure 3This diagram illustrates the first correspondence between leakage current and detection time at different temperatures according to one or more embodiments. The embodiment uses a SOC of 60% as an example, and the current is expressed in mA. In this diagram, the horizontal axis represents time, and the vertical axis represents leakage current. Curve 1 corresponds to the leakage current of the battery cell changing with time at 70°C; Curve 2 corresponds to the leakage current of the battery cell changing with time at 60°C; Curve 3 corresponds to the leakage current of the battery cell changing with time at 45°C; and Curve 4 corresponds to the leakage current of the battery cell changing with time at 25°C.

[0073] In some embodiments, continuous voltage data under constant voltage conditions can also be acquired, thereby enabling a determination of whether the actual measured voltage is consistent with the voltage maintained during the constant voltage test.

[0074] In step S21, based on the first correspondence, the detection time corresponding to the stable state of leakage current is determined.

[0075] In some embodiments, a steady state of leakage current includes a difference in leakage current between adjacent times that is less than a threshold.

[0076] For example, starting from day 5, the leakage current fluctuates less over time. Therefore, the leakage current at different temperatures at any given moment on any day from day 5 to day 10 can be selected. By determining the steady-state of the current, the leakage current data for the corresponding time can be extracted, thus facilitating the construction of the correlation between leakage current and temperature.

[0077] In step S311, the leakage current of the battery cells corresponding to multiple test temperatures at the detection time corresponding to the stable state of leakage current is extracted, and a first coordinate system is constructed with the logarithm of the leakage current as the vertical axis and the reciprocal of the test temperature as the horizontal axis.

[0078] In step S312, in the first coordinate system, the leakage current of the cells corresponding to multiple test temperatures at the detection time corresponding to the stable state of leakage current is linearly fitted to obtain the first fitted straight line.

[0079] like Figure 4 As shown, Figure 4 This figure shows a second correspondence between the logarithm of the leakage current and the reciprocal of the test temperature according to one or more embodiments. In this figure, data is plotted and fitted in a coordinate system with the reciprocal of the test temperature 1 / T as the abscissa and the logarithm of the leakage current Lnk as the ordinate to obtain a first fitted straight line A. The temperature in the coordinate system is, for example, in Kelvin.

[0080] In step S41, the slope corresponding to the first fitted straight line is determined as the temperature acceleration coefficient.

[0081] In this embodiment, constant voltage tests are performed on the battery cell at multiple set temperatures to obtain data on the leakage current change over time at different temperatures. Then, the stable current value is taken to establish the correspondence between leakage current and temperature. By calculating the slope of the first fitted straight line, the temperature acceleration coefficient can be quickly determined.

[0082] In some embodiments, the temperature boundary for use of the battery cell is determined based on discrete points in a first fitted straight line.

[0083] For example, if a certain temperature deviates significantly from other temperatures, it indicates that this temperature has affected the normal degradation mechanism of the battery cell. This method can be used to confirm the operating temperature boundary of the battery cell. The temperature boundary is... Figure 4 The middle part corresponds to the position on the left side of the horizontal axis, such as... Figure 4 The temperature corresponding to point B shown is the boundary temperature. By quickly determining the temperature boundary of the battery cell, we can reduce the safety risks of the cell, prevent thermal runaway, and provide support for ensuring the safe, efficient, and long-life operation of the cell. It is also the basis for the design, use, and management system development of batteries.

[0084] In some embodiments, the test parameters include the test state of charge, the second correspondence includes the second correspondence between leakage current and the test state of charge, and the decay acceleration factor includes the state of charge acceleration factor.

[0085] For example, a first correspondence between the leakage current of the battery cell and the detection time is obtained under multiple test SOCs; based on the first correspondence, the detection time corresponding to the steady state of the leakage current is determined; the leakage current of the battery cell corresponding to multiple test SOCs under the detection time corresponding to the steady state of the leakage current is extracted to construct a second correspondence between the leakage current of the battery cell and the test SOC; based on the second correspondence, the SOC acceleration coefficient is determined.

[0086] In this embodiment, by acquiring data on the leakage current of the battery cell changing over time under different SOCs, a second correspondence between the leakage current of the battery cell and SOC is established, thereby enabling the rapid acquisition of the SOC acceleration coefficient. This provides important parameters for the subsequent construction of the battery life model, thereby improving the accuracy of battery life prediction.

[0087] Those skilled in the art should understand that the SOC acceleration factor corresponds to the voltage acceleration factor, and the SOC acceleration factor can be converted into the voltage acceleration factor through certain derivation.

[0088] In some embodiments, the second correspondence is represented by a second fitted straight line in a second coordinate system. Constructing the second correspondence between the leakage current of the battery cell and the test parameters includes: constructing a second coordinate system with leakage current as the vertical axis and the test state of charge as the horizontal axis; in the second coordinate system, linearly fitting the leakage current of the battery cells corresponding to multiple test states of charge at the detection time corresponding to the stable state of leakage current to obtain the second fitted straight line.

[0089] For example, when the leakage current of the battery cell is in a stable state, after obtaining multiple sets of leakage current data under different SOCs, a straight line is plotted in a second coordinate system with leakage current as the vertical axis and the test SOC as the horizontal axis. This straight line represents the second correspondence between leakage current and SOC. Using the fitted straight line in the coordinate system to represent the second correspondence between leakage current and SOC facilitates the rapid and intuitive determination of the SOC acceleration factor.

[0090] In some embodiments, determining the attenuation acceleration coefficient based on the second correspondence includes: determining the slope corresponding to the second fitted straight line as the state-of-charge acceleration coefficient.

[0091] For example, the SOC acceleration factor satisfies the formula I=ax soc +b, I represents leakage current, x soc Let SOC represent the slope a, which represents the SOC acceleration coefficient, and b be the intercept of the fitted line.

[0092] In this embodiment, after obtaining a fitted straight line representing the relationship between leakage current and SOC through linear fitting, the SOC acceleration factor can be determined by calculating the slope of the fitted straight line. The calculation process is simple and does not require a large amount of data, thus improving the efficiency of determining the SOC acceleration factor.

[0093] Figure 5 This is a schematic diagram of a method for obtaining the SOC acceleration factor of a battery cell according to one or more embodiments, which includes steps S12-S42.

[0094] In step S12, the first correspondence between the leakage current of the battery cell and the detection time is obtained under multiple test SOCs.

[0095] For example, as shown in Table 1, the SOC of the battery cell was set to 60%, 20%, and 5%, and then constant temperature and constant voltage tests were performed. The voltage corresponding to 5% SOC was 3.138V, 20% SOC was 3.25V, and 60% SOC was 3.32V. The sampling interval was, for example, 10 seconds, and the test period was, for example, 10 days, thus obtaining continuous leakage current data under constant voltage conditions.

[0096] like Figure 6 As shown, Figure 6This diagram illustrates the first correspondence between leakage current and detection time at different SOCs according to one or more embodiments. In this embodiment, 60°C is used as an example. The horizontal axis represents time, and the vertical axis represents leakage current, with units of mA. Curve 5 corresponds to the leakage current of the cell over time at 60% SOC; curve 6 corresponds to the leakage current of the cell over time at 20% SOC; and curve 7 corresponds to the leakage current of the cell over time at 5% SOC.

[0097] In step S22, based on the first correspondence, the detection time corresponding to the stable state of leakage current is determined.

[0098] For example, day 9 can be selected as the detection time corresponding to the stable state of leakage current.

[0099] In step S321, the leakage current of the cells corresponding to multiple test states of charge at the detection time corresponding to the stable state of leakage current is extracted, and a second coordinate system is constructed with leakage current as the vertical axis and test states of charge as the horizontal axis.

[0100] In step S322, in the second coordinate system, the leakage current of the cells corresponding to multiple test states of charge at the detection time corresponding to the stable state of leakage current is linearly fitted to obtain the second fitted straight line.

[0101] like Figure 7 As shown, Figure 7 This is a schematic diagram of the second correspondence between leakage current and test SOC according to one or more embodiments. In this figure, data is plotted and fitted in a second coordinate system with leakage current I as the vertical axis and test SOC as the horizontal axis to obtain a second fitted straight line C.

[0102] In step S42, the slope corresponding to the second fitted line is determined as the state-of-charge acceleration coefficient.

[0103] In this embodiment, constant voltage tests are performed on the battery cell under multiple set SOCs to obtain data on the leakage current change over time under different SOCs. Then, the stable current value is taken to establish the correspondence between leakage current and SOC. By calculating the slope of the second fitted straight line, the SOC acceleration coefficient can be quickly determined.

[0104] Those skilled in the art will understand that, in the methods described above in specific embodiments, the order in which the steps are written does not imply a strict execution order and does not constitute any limitation on the real-time process. The specific execution order of each step should be determined by its function and possible internal logic.

[0105] The above are schematic diagrams of some embodiments of the method for obtaining the cell degradation acceleration coefficient. Below, the system for obtaining the cell degradation acceleration coefficient will be further described with reference to the accompanying drawings.

[0106] Figure 8 This is a schematic diagram of a system for obtaining the cell degradation acceleration coefficient according to one or more embodiments. Figure 1 The system 8 for obtaining the cell attenuation acceleration coefficient includes a first determining module 81, a time determining module 82, a second determining module 83, and a coefficient determining module 84.

[0107] The first determining module 81 is configured to determine the first correspondence between the leakage current of the battery cell and the detection time under multiple test values ​​of the same test parameter.

[0108] In some embodiments, test parameters include test temperature or test SOC.

[0109] In some embodiments, the leakage current is determined by compensating for the self-discharge current of the battery cell using a constant voltage method.

[0110] By using an external constant voltage source, the energy loss caused by the self-discharge of the battery cell is compensated in real time, so that the battery cell voltage remains constant. At this time, the externally input compensation current is the self-discharge current of the battery cell, which is also called the leakage current.

[0111] The time determination module 82 is configured to determine the detection time corresponding to the stable state of leakage current based on the first correspondence.

[0112] In some embodiments, a steady state of leakage current includes a difference in leakage current between adjacent times that is less than a threshold.

[0113] The leakage current fluctuates little over time, indicating that the leakage current is in a stable state.

[0114] The second determining module 83 is configured to extract the leakage current of the cell corresponding to multiple test values ​​under the detection time corresponding to the stable state of leakage current, so as to construct a second correspondence between the leakage current of the cell and the test parameters.

[0115] In some embodiments, if the test parameters include the test temperature, the second correspondence includes a second correspondence between the logarithm of the leakage current and the reciprocal of the test temperature.

[0116] In other embodiments, if the test parameters include the test state of charge, then the second correspondence includes a second correspondence between the leakage current and the test state of charge.

[0117] The coefficient determination module 84 is configured to determine the attenuation acceleration coefficient based on the second correspondence.

[0118] In some embodiments, if the test parameters include the test temperature, then the attenuation acceleration factor includes the temperature acceleration factor.

[0119] In other embodiments, if the test parameters include the test state of charge, then the decay acceleration factor includes the state of charge acceleration factor.

[0120] By utilizing the leakage current principle of the battery cell, a primary correspondence between leakage current and detection time is first established. Then, the leakage current of the battery cell corresponding to multiple test values ​​is extracted at the detection time corresponding to the stable leakage current state. This allows for the construction of a secondary correspondence between leakage current and test parameters, thereby determining the degradation acceleration coefficient. This eliminates the need for long-term data monitoring and complex data calculations, thus improving the efficiency and reliability of obtaining the degradation acceleration coefficient and facilitating rapid and accurate prediction of battery life.

[0121] In some embodiments, the second correspondence is represented by a first fitted straight line in the first coordinate system. The second determining module 83 is configured to construct a first coordinate system with the logarithm of the leakage current as the vertical axis and the reciprocal of the test temperature as the horizontal axis. In the first coordinate system, the leakage current of multiple cells corresponding to multiple test temperatures at the detection time corresponding to the stable state of the leakage current is linearly fitted to obtain the first fitted straight line.

[0122] In this embodiment, a first fitted straight line represents the second correspondence between the logarithm of the leakage current and the reciprocal of the test temperature, which facilitates the subsequent intuitive and rapid determination of the temperature acceleration factor.

[0123] In some embodiments, the coefficient determination module 84 is configured to determine the slope corresponding to the first fitted straight line as the temperature acceleration coefficient.

[0124] In this embodiment, after obtaining a fitted straight line representing the relationship between leakage current and temperature through linear fitting, the temperature acceleration coefficient can be determined by calculating the slope of the fitted straight line. The calculation process is simple and does not require a large amount of data, thus improving the efficiency of determining the temperature acceleration coefficient.

[0125] In some embodiments, Figure 9 This is a schematic diagram of a system for obtaining the cell degradation acceleration coefficient according to one or more embodiments. Figure 2 The system for obtaining the cell's degradation acceleration coefficient also includes a boundary determination module 91, configured to determine the temperature boundary used by the cell based on discrete points in a first fitted straight line.

[0126] For example, if a certain temperature deviates significantly from other temperatures, it indicates that this temperature has affected the normal degradation mechanism of the battery cell, thus confirming the cell's operating temperature boundary. Quickly determining the cell's temperature boundary can reduce cell safety risks, prevent thermal runaway, and provide support for ensuring the safe, efficient, and long-life operation of the cell. It also serves as the foundation for battery design, usage, and management system development.

[0127] In some embodiments, the second correspondence is represented by a second fitted straight line in a second coordinate system. The second determining module 83 is configured to construct a second coordinate system with leakage current as the vertical axis and test state of charge as the horizontal axis. In the second coordinate system, the leakage current of multiple cells corresponding to test states of charge at the detection time corresponding to the stable state of leakage current is linearly fitted to obtain the second fitted straight line.

[0128] The second correspondence between leakage current and SOC is represented by a fitted straight line in the coordinate system, which facilitates the rapid and intuitive determination of the SOC acceleration factor.

[0129] In some embodiments, the coefficient determination module 84 is configured to determine the slope corresponding to the second fitted straight line as the state-of-charge acceleration coefficient.

[0130] In this embodiment, after obtaining a fitted straight line representing the relationship between leakage current and SOC through linear fitting, the SOC acceleration factor can be determined by calculating the slope of the fitted straight line. The calculation process is simple and does not require a large amount of data, thus improving the efficiency of determining the SOC acceleration factor.

[0131] Figure 10 This is a schematic diagram of a system for obtaining the cell degradation acceleration coefficient according to one or more embodiments. Figure 3 The system for obtaining the cell's degradation acceleration factor can be implemented electronically. The system 8 for obtaining the cell's degradation acceleration factor includes a memory 1010 and a processor 1020. The memory 1010 can be a disk, flash memory, or any other non-volatile storage medium. The memory is used to store the instructions in the above embodiments. The processor 1020 is coupled to the memory 1010 and can be implemented as one or more integrated circuits, such as a microprocessor or microcontroller. The processor 1020 is used to execute the instructions stored in the memory.

[0132] In some embodiments, the processor 1020 is coupled to the memory 1010 via a BUS bus 1030. The system 8 for obtaining the cell's degradation acceleration factor can also be connected to an external storage device 1050 via a storage interface 1040 to access external data, and can also be connected to a network or another computer system (not shown) via a network interface 1060. Further details are omitted here.

[0133] In this embodiment, by storing data instructions in a memory and then processing the instructions by a processor, the efficiency and accuracy of obtaining the cell degradation acceleration coefficient can be improved, thereby facilitating rapid and accurate prediction of battery life.

[0134] In other embodiments, this application provides a computer-readable storage medium having computer program instructions stored thereon, which, when executed by a processor, implement the steps of the methods described above. Those skilled in the art will understand that embodiments of this application can be provided as methods, apparatus, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable non-transitory storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0135] In some embodiments of the application, a computer program product is also provided, including computer program instructions that, when executed by a processor, implement the method of any of the above embodiments.

[0136] The description of the various embodiments above tends to emphasize the differences between the various embodiments. The similarities or similarities between them can be referred to, and for the sake of brevity, they will not be repeated here.

[0137] This concludes the detailed description of this application. To avoid obscuring the concept of this application, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0138] The methods and systems of this application may be implemented in many ways. For example, they may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above-described order of steps for the methods is for illustrative purposes only, and the steps of the methods of this application are not limited to the order specifically described above, unless otherwise specifically stated. Furthermore, in some embodiments, this application may also be implemented as a program recorded on a recording medium, the program including machine-readable instructions for implementing the methods according to this application. Thus, this application also covers recording media storing programs for performing the methods according to this application.

[0139] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. A method for obtaining the degradation acceleration coefficient of a battery cell, characterized in that, include: Determine the first correspondence between the leakage current of the battery cell and the detection time under multiple test values ​​of the same test parameter; Based on the first correspondence, the detection time corresponding to the stable state of leakage current is determined, wherein the stable state of leakage current includes the difference between leakage currents at adjacent times being less than a threshold. Extract the leakage current of the cell corresponding to the multiple test values ​​at the detection time corresponding to the stable state of the leakage current, so as to construct a second correspondence between the leakage current of the cell and the test parameters; Based on the second correspondence, the attenuation acceleration coefficient is determined.

2. The method for obtaining the cell degradation acceleration coefficient according to claim 1, characterized in that, The test parameters include the test temperature, the second correspondence includes the second correspondence between the logarithm of the leakage current and the reciprocal of the test temperature, and the attenuation acceleration coefficient includes the temperature acceleration coefficient.

3. The method for obtaining the cell degradation acceleration coefficient according to claim 2, characterized in that, The second correspondence is represented by a first fitted straight line in the first coordinate system. Constructing the second correspondence between the leakage current of the battery cell and the test parameters includes: Construct a first coordinate system with the logarithm of the leakage current as the ordinate and the reciprocal of the test temperature as the abscissa; In the first coordinate system, the logarithmic values ​​of the leakage current of the battery cell corresponding to the reciprocals of multiple test temperatures at the detection time corresponding to the stable state of the leakage current are linearly fitted to obtain the first fitted straight line.

4. The method for obtaining the cell degradation acceleration coefficient according to claim 3, characterized in that, Based on the second correspondence, the attenuation acceleration coefficient is determined as follows: The slope corresponding to the first fitted straight line is determined as the temperature acceleration coefficient.

5. The method for obtaining the cell degradation acceleration coefficient according to claim 3, characterized in that, Also includes: The temperature boundary for the battery cell is determined based on the discrete points in the first fitted straight line.

6. The method for obtaining the cell degradation acceleration coefficient according to claim 1, characterized in that, The test parameters include the test state of charge, the second correspondence includes the second correspondence between the leakage current and the test state of charge, and the attenuation acceleration factor includes the state of charge acceleration factor.

7. The method for obtaining the cell degradation acceleration coefficient according to claim 6, characterized in that, The second correspondence is represented by a second fitted straight line in a second coordinate system. Constructing the second correspondence between the leakage current of the battery cell and the test parameters includes: Construct a second coordinate system with the leakage current as the vertical axis and the test state of charge as the horizontal axis; In the second coordinate system, the leakage current of the cell corresponding to multiple test states of charge at the detection time corresponding to the stable state of leakage current is linearly fitted to obtain the second fitted straight line.

8. The method for obtaining the cell degradation acceleration coefficient according to claim 7, characterized in that, Based on the second correspondence, the attenuation acceleration coefficient is determined as follows: The slope corresponding to the second fitted line is determined as the state-of-charge acceleration coefficient.

9. The method for obtaining the cell degradation acceleration coefficient according to any one of claims 1 to 8, characterized in that, The leakage current is determined by compensating for the self-discharge current of the battery cell using a constant voltage method.

10. A system for obtaining the degradation acceleration coefficient of a battery cell, characterized in that, include: The first determining module is configured to determine a first correspondence between the leakage current of the battery cell and the detection time under multiple test values ​​of the same test parameter; The time determination module is configured to determine the detection time corresponding to the stable state of leakage current based on the first correspondence, wherein the stable state of leakage current includes the difference between leakage currents at adjacent times being less than a threshold. The second determining module is configured to extract the leakage current of the cell corresponding to the multiple test values ​​at the detection time corresponding to the stable state of the leakage current, so as to construct a second correspondence between the leakage current of the cell and the test parameters. The coefficient determination module is configured to determine the attenuation acceleration coefficient based on the second correspondence.

11. A system for obtaining the degradation acceleration coefficient of a battery cell, characterized in that, include: processor; as well as A memory coupled to the processor is used to store instructions that, when executed by the processor, cause the processor to perform the method for obtaining the cell's degradation acceleration factor as described in any one of claims 1 to 9.

12. A computer-readable storage medium storing computer instructions thereon, characterized in that, When executed by a processor, the computer instructions implement the method for obtaining the cell degradation acceleration coefficient as described in any one of claims 1 to 9.

13. A computer program product, characterized in that, include: The method includes computer instructions that, when executed by a processor, implement the method for obtaining the cell degradation acceleration coefficient as described in any one of claims 1 to 9.

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