Method and system for obtaining attenuation acceleration coefficient of battery cell, medium and program product

Abstract

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

Description

TECHNICAL FIELD

[0001] The present application relates to the field of battery, and particularly relates to a method, system, medium and program product for obtaining attenuation acceleration coefficient of battery cell. BACKGROUND

[0002] When battery life is evaluated, long-period data is needed to determine reliable attenuation acceleration coefficient of battery cell in order to establish battery cell life attenuation equation under different working conditions.

[0003] The above statements are only used to provide background technical information related to the present application, and do not necessarily constitute prior art. SUMMARY

[0004] One technical problem to be solved by the present disclosure is to provide a method, system, medium and program product for obtaining attenuation acceleration coefficient of battery cell, which can improve the efficiency of obtaining attenuation acceleration coefficient of battery cell.

[0005] According to one aspect of the present disclosure, a method for obtaining attenuation acceleration coefficient of battery cell is provided, comprising: determining a first correspondence between leakage current and detection time of the battery cell under a plurality of test values of the same test parameter; determining detection time corresponding to leakage current stable state based on the first correspondence, wherein the leakage current stable state comprises a difference value of leakage current of adjacent time being less than a threshold value; extracting leakage current of the battery cell corresponding to the plurality of test values under the detection time corresponding to the leakage current stable state to construct a second correspondence between leakage current and test parameter of the battery cell; and determining attenuation acceleration coefficient based on the second correspondence.

[0006] In the technical scheme of the present application, the first correspondence between leakage current and detection time is established, and the leakage current of the battery cell corresponding to the plurality of test values is extracted at the detection time corresponding to the leakage current stable state, so as to construct the second correspondence between leakage current and test parameter, and then determine the attenuation acceleration coefficient, without long-period data monitoring and complex data calculation, so as to determine the attenuation acceleration coefficient of the battery cell, 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 parameter comprises test temperature, the second correspondence comprises a second correspondence between logarithmic value of the leakage current and inverse of the test temperature, and the attenuation acceleration coefficient comprises temperature acceleration coefficient. In this embodiment, the second correspondence between leakage current and temperature of the battery cell is established by obtaining data of change of leakage current of the battery cell with time under different temperatures, and then the temperature acceleration coefficient can be quickly obtained, which provides an important parameter for subsequent construction of life model of the battery, thereby improving the accuracy of prediction of battery life.

[0008] In some embodiments, the second correspondence is represented by a first fitting straight line in a first coordinate system, and the constructing the second correspondence between the leakage current of the battery cell and the test parameter comprises: constructing the first coordinate system with the logarithmic value of the leakage current as the ordinate and the reciprocal of the test temperature as the abscissa; in the first coordinate system, performing linear fitting on the logarithmic value of the leakage current corresponding to the reciprocal of the plurality of test temperatures at the detection time corresponding to the leakage current steady state to obtain the first fitting straight line. The second correspondence between the leakage current and the temperature is represented by the fitting straight line in the coordinate system, which facilitates subsequent intuitive and rapid determination of the temperature acceleration coefficient.

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

[0010] In some embodiments, the temperature boundary used by the battery cell is determined according to the discrete points in the first fitting straight line. By quickly determining the temperature boundary of the battery cell, the safety risk of the battery cell can be reduced, and thermal runaway can be prevented, which provides support for ensuring safe, efficient and long-life operation of the battery cell, and is also a basic basis for the development of battery design, use and management system.

[0011] In some embodiments, the test parameter comprises a test state of charge, the second correspondence comprises a second correspondence between the leakage current and the test state of charge, and the attenuation acceleration coefficient comprises a state of charge acceleration coefficient. In this embodiment, by obtaining the data of the leakage current of the battery cell changing over time at different SOC, the second correspondence between the leakage current and the SOC of the battery cell is established, and the SOC acceleration coefficient can be quickly obtained, which provides an important parameter for the subsequent construction of the life model of the battery, thereby improving the accuracy of the life prediction of the battery.

[0012] In some embodiments, the second correspondence is represented by a second fitting straight line in a second coordinate system, and the constructing the second correspondence between the leakage current of the battery cell and the test parameter comprises: constructing the second coordinate system with the leakage current as the ordinate and the test state of charge as the abscissa; in the second coordinate system, performing linear fitting on the leakage current of the battery cell corresponding to the plurality of test states of charge at the detection time corresponding to the leakage current steady state to obtain the second fitting straight line. The second correspondence between the leakage current and the SOC is represented by the fitting straight line in the coordinate system, which facilitates subsequent rapid and intuitive determination of the SOC acceleration coefficient.

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

[0014] In some embodiments, the leakage current is determined by compensating the self-discharge current of the battery cell in a constant voltage mode. The compensated current should be equal to the self-discharge current of the battery cell, so that the leakage current of the battery cell can be quickly obtained, and the determination of the attenuation acceleration coefficient of the battery cell is facilitated.

[0015] According to a second aspect of the present disclosure, a system for obtaining an attenuation acceleration coefficient of a battery cell is also provided, comprising: a first determination module configured to determine 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; a time determination module configured to determine a detection time corresponding to a leakage current stable state based on the first correspondence relationship, the leakage current stable state comprising a difference between leakage currents of adjacent times being less than a threshold value; a second determination module configured to extract the leakage current of the battery cell corresponding to the plurality of test values at the detection time corresponding to the leakage current stable state, to construct a second correspondence relationship between the leakage current of the battery cell and the test parameter; and a coefficient determination module configured to determine an attenuation acceleration coefficient based on the second correspondence relationship.

[0016] In the technical solution of the embodiments of the present application, the first correspondence relationship between the leakage current and the detection time is established by using the principle of the leakage current of the battery cell, and the leakage current of the battery cell corresponding to the plurality of test values is extracted at the detection time corresponding to the leakage current stable state, so that the second correspondence relationship between the leakage current and the test parameter can be constructed, and the attenuation acceleration coefficient can be determined without long-period data monitoring and complex data calculation, thereby improving the efficiency and reliability of obtaining the attenuation acceleration coefficient, and facilitating subsequent rapid and accurate prediction of the battery life.

[0017] According to a third aspect of the present disclosure, a system for obtaining an attenuation acceleration coefficient of a battery cell is also provided, comprising: a processor; and a memory coupled to the processor and configured to store instructions, the instructions being executed by the processor to cause the processor to perform the method for obtaining the attenuation acceleration coefficient of the battery cell as described above.

[0018] According to a fourth aspect of the present disclosure, a computer readable storage medium is further provided, which stores computer instructions, and the computer instructions are executed by a processor to implement the method for obtaining the attenuation acceleration coefficient of the battery cell.

[0019] According to a fifth aspect of the present disclosure, a computer program product is further provided, which comprises computer instructions, and the computer instructions are executed by a processor to implement the method for obtaining the attenuation acceleration coefficient of the battery cell.

[0020] Other features and advantages of the present disclosure will become apparent from the following detailed description of exemplary embodiments thereof, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced as follows. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can also be obtained by the drawings without creative labor for those skilled in the art.

[0022] Figure 1 A schematic diagram of the method for obtaining the attenuation acceleration coefficient of the battery cell according to one or more embodiments; Figure 2 A schematic diagram of the method for obtaining the temperature acceleration coefficient of the battery cell according to one or more embodiments; Figure 3 A schematic diagram of the first correspondence between the leakage current and the detection time at different temperatures according to one or more embodiments; Figure 4 A schematic diagram of the second correspondence between the logarithmic value of the leakage current and the reciprocal of the test temperature according to one or more embodiments; Figure 5 A schematic diagram of the method for obtaining the SOC acceleration coefficient of the battery cell according to one or more embodiments; Figure 6 A schematic diagram of the first correspondence between the leakage current and the detection time at different SOC according to one or more embodiments; Figure 7 A schematic diagram of the second correspondence between the leakage current and the test SOC according to one or more embodiments; Figure 8 A schematic diagram of the system for obtaining the attenuation acceleration coefficient of the battery cell according to one or more embodiments Figure 1 ; Figure 9 A schematic diagram of the system for obtaining the attenuation acceleration coefficient of the battery cell according to one or more embodiments Figure 2 ; Figure 10Schematic of a system for obtaining an attenuation acceleration coefficient of an electric cell according to one or more embodiments Figure 3 . DETAILED DESCRIPTION

[0023] The embodiments of the present application will be described in further detail below with reference to the accompanying drawings and examples. The following detailed description and examples are provided as exemplary of the principles of the application and are not meant to limit the application as described in the attached claims.

[0024] In the description of the present application, it is necessary to note that, unless otherwise specified, the meaning of "a plurality of" is more than two; the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer" and the like is only for the purpose of facilitating the description of the present application and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" and the like are only for the purpose of description and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly vertical, but within the allowable range of error. "Parallel" is not strictly parallel, but within the allowable range of error.

[0025] At the same time, it should be understood that, for the purpose of description, the size of each part shown in the drawings is not drawn in accordance with the actual proportional relationship.

[0026] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the disclosure, its application or uses.

[0027] Techniques, methods, and devices known to those of ordinary skill in the relevant art can not be discussed in detail herein. However, where appropriate, such techniques, methods, and devices can be considered part of the specification.

[0028] In all examples shown and discussed herein, any specific values should be interpreted as merely illustrative and not as a limitation. Thus, other examples of the exemplary embodiments can have different values.

[0029] It should be noted that: similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be discussed further in subsequent drawings.

[0030] In order to make the purpose, technical scheme and advantages of the present disclosure clearer, the present disclosure will be further described in detail below with reference to specific embodiments and with reference to the accompanying drawings.

[0031] With the increasing demand for battery life evaluation, it is necessary to develop a rapid life evaluation method. The reliability of the important parameters in the life model and the data processing method are closely related to the length of the test data. In the related art, test data under different test parameters for a long period of time need to be obtained, and then through complex data processing, the attenuation acceleration coefficient of the battery can be determined. If the data acquisition time is short, the short data length directly affects the reliability of the fitting result. In the case of rapid and accurate prediction of battery life, this test method with difficult data acquisition, long test period and high cost obviously needs to be improved.

[0032] The present disclosure provides a scheme for obtaining the attenuation acceleration coefficient of the battery, which can improve the efficiency and accuracy of obtaining the attenuation acceleration coefficient of the battery, thereby facilitating subsequent rapid and accurate prediction of battery life. In the following, the scheme of the present disclosure will be introduced in combination with the drawings.

[0033] Figure 1 For a schematic diagram of the method for obtaining the attenuation acceleration coefficient of the battery according to one or more embodiments, the embodiment includes steps S1-S4.

[0034] In step S1, a first correspondence relationship between the leakage current of the battery and the detection time under a plurality of test values of the same test parameter is determined.

[0035] The test parameter is a parameter related to the attenuation of the battery, for example, including test temperature, test SOC (State Of Charge, state of charge), test humidity, etc. The embodiment creates a plurality of test environments to obtain the data of the change of the leakage current of the battery with 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 unit of day, the unit of second, etc. herein are only used for example, and the frequency and period of use can be set according to the actual situation.

[0036] During storage, the capacity attenuation of the battery is manifested as the self-discharge of the battery. In the embodiment, the attenuation acceleration coefficient of the battery is calculated by the leakage current of the battery.

[0037] The battery is for example a conventional laminated or soft-pack battery.

[0038] For ease of observation, the first correspondence relationship is for example displayed by means of a coordinate system. Those skilled in the art should understand that the obtained data can also be recorded in a table or the like.

[0039] In step S2, the detection time corresponding to the stable state of the leakage current is determined based on the first correspondence relationship.

[0040] In some embodiments, by observing the correspondence between the leakage current of the battery cell and the detection time, it can be found that the leakage current of the battery cell will be in a stable state after a period of time. Subsequently, in order to determine the correspondence between the leakage current and the test parameter, it is necessary to determine at what time the leakage current of the battery cell is in a stable state.

[0041] In step S3, the leakage current of the battery cell corresponding to the test values at the detection time corresponding to the stable state of the leakage current is extracted to construct a second correspondence between the leakage current of the battery cell and the test parameter.

[0042] For ease of observation, the second correspondence is displayed, for example, by means of a coordinate system. Those skilled in the art should understand that the obtained data can also be recorded in a table or the like.

[0043] In step S4, the attenuation acceleration coefficient is determined based on the second correspondence.

[0044] In this embodiment, by using the principle of the leakage current of the battery cell, a first correspondence between the leakage current and the detection time is first established, and the leakage current of the battery cell corresponding to the test values at the detection time corresponding to the stable state of the leakage current is extracted, so as to construct a second correspondence between the leakage current and the test parameter, and then determine the attenuation acceleration coefficient. Without long-period data monitoring and complex data calculation, the attenuation acceleration coefficient of the battery cell can be determined, thereby improving the efficiency and reliability of obtaining the attenuation acceleration coefficient, and facilitating subsequent rapid and accurate prediction of the battery life.

[0045] In some embodiments, the leakage current is determined by compensating the self-discharge current of the battery cell in a constant voltage mode.

[0046] For example, when the battery cell is not used, the internal current will naturally leak, i.e., the self-discharge current. The self-discharge current of the battery cell is compensated in a constant voltage mode. 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, which facilitates subsequent determination of the attenuation acceleration coefficient of the battery cell.

[0047] In some embodiments, the test parameter includes a test temperature, the second correspondence includes a second correspondence between the logarithmic value of the leakage current and the inverse of the test temperature, and the attenuation acceleration coefficient includes a temperature acceleration coefficient.

[0048] For example, a first correspondence between the leakage current of the battery cell and the detection time at a plurality of test temperatures is obtained; based on the first correspondence, a detection time corresponding to a stable state of the leakage current is determined; the leakage current of the battery cell corresponding to the test temperature at the detection time corresponding to the stable state of the leakage current is extracted to construct a second correspondence between the leakage current of the battery cell and the test temperature; and based on the second correspondence, a temperature acceleration coefficient is determined.

[0049] In this embodiment, by obtaining the data of the leakage current of the battery cell changing with time at different temperatures, the second correspondence relationship between the leakage current of the battery cell and the temperature is established, and then the temperature acceleration coefficient can be quickly obtained, which provides an important parameter for the subsequent construction of the life model of the battery, thereby improving the accuracy of the battery life prediction.

[0050] In some embodiments, the second correspondence relationship is represented by a first fitting straight line in a first coordinate system, and the construction of the second correspondence relationship between the leakage current of the battery cell and the test parameter includes: constructing a first coordinate system with the logarithmic value of the leakage current as the vertical coordinate and the reciprocal of the test temperature as the horizontal coordinate; in the first coordinate system, linearly fitting the logarithmic value of the leakage current of the battery cell corresponding to the reciprocal of the test temperature at the detection time corresponding to the stable state of the leakage current, to obtain the first fitting straight line.

[0051] For example, when the leakage current of the battery cell is in a stable state, after obtaining a plurality of groups of leakage current data at different temperatures, a straight line is drawn in the first coordinate system with the logarithmic value of the leakage current as the vertical coordinate and the reciprocal of the test temperature as the horizontal coordinate, so as to represent the second correspondence relationship between the leakage current and the temperature by the straight line. The second correspondence relationship between the leakage current and the temperature is represented by the fitting straight line in the coordinate system, which facilitates subsequent intuitive and rapid determination of the temperature acceleration coefficient.

[0052] In some embodiments, based on the second correspondence relationship, the determination of the attenuation acceleration coefficient includes: determining the slope corresponding to the first fitting straight line as the temperature acceleration coefficient.

[0053] For example, the temperature acceleration coefficient satisfies the Arrhenius equation: k=A*e^(-Ea / RT), where k represents the reaction rate and also represents the size of the leakage current; A is the frequency factor; R is the molar gas constant, which is a known quantity; T is the thermodynamic temperature, and Ea is the activation energy. In the leakage current test, the logarithm of both sides of the Arrhenius equation is taken to obtain lnk = lnA - Ea / (R*T), so that a straight line can be drawn in the first coordinate system, where the slope is -Ea / R and the intercept is lnA; -Ea / R represents the temperature acceleration coefficient.

[0054] In this embodiment, after the fitting straight line representing the correspondence relationship between the leakage current and the temperature is obtained by linear fitting, the temperature acceleration coefficient can be determined by calculating the slope of the fitting straight line. The calculation process is simple, and a large amount of data is not required, so that the efficiency of determining the temperature acceleration coefficient is improved.

[0055] Figure 2 A schematic diagram of a method for obtaining a temperature acceleration coefficient of a battery cell according to one or more embodiments, which includes steps S11-S41.

[0056] In step S11, the first correspondence between the leakage current of the battery cell and the detection time is obtained under multiple test temperatures.

[0057] 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: Table 1 shows the constant pressure test temperature matrix and the number of samples.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] like Figure 3 As shown, Figure 3 This 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.

[0062] 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.

[0063] In step S21, based on the first correspondence, the detection time corresponding to the stable state of leakage current is determined.

[0064] In some embodiments, the leakage current steady state includes a difference of leakage current of adjacent times being less than a threshold value.

[0065] For example, from the 5th day, the leakage current floats less over time, thus, the leakage current at different temperatures at a certain time of any day from the 5th day to the 10th day can be selected. By determining the current steady state, the leakage current data at the corresponding time can be extracted, thereby facilitating the construction of the corresponding relationship between the leakage current and the temperature.

[0066] In step S311, the leakage current of the battery cell corresponding to the plurality of test temperatures at the detection time corresponding to the leakage current steady state is extracted, and a first coordinate system taking the logarithmic value of the leakage current as the ordinate and the reciprocal of the test temperature as the abscissa is constructed.

[0067] In step S312, the leakage current of the battery cell corresponding to the plurality of test temperatures at the detection time corresponding to the leakage current steady state is linearly fitted in the first coordinate system, and a first fitting straight line is obtained.

[0068] As shown in Figure 4 , Figure 4 is a second corresponding relationship diagram of the logarithmic value of the leakage current and the reciprocal of the test temperature according to one or more embodiments, in which the reciprocal of the test temperature 1 / T is taken as the abscissa and the logarithmic value of the leakage current Ln k is taken as the ordinate in the coordinate system, data plotting and fitting are performed to obtain a first fitting straight line A, and the temperature in the coordinate is for example in units of Kelvin.

[0069] In step S41, the slope corresponding to the first fitting straight line is determined as the temperature acceleration coefficient.

[0070] In this embodiment, the battery cell is tested at a plurality of set temperatures to obtain the data of the leakage current changing over time at different temperatures, and then the stable current value is taken to establish the corresponding relationship between the leakage current and the temperature, and the slope of the first fitting straight line is calculated to quickly determine the temperature acceleration coefficient.

[0071] In some embodiments, the temperature boundary used by the battery cell is determined according to the discrete points in the first fitting straight line.

[0072] For example, if a certain temperature deviates significantly from the trend of other temperatures, it indicates that the temperature has affected the normal decay mechanism of the battery cell, and the temperature boundary used by the battery cell can be confirmed by this method. The temperature boundary corresponds to a position near the left side of the abscissa in Figure 4 , as shown by the point B corresponding to the temperature in Figure 4 . By quickly determining the temperature boundary of the battery cell, the safety risk of the battery cell can be reduced, and the thermal runaway can be prevented, thereby providing support for ensuring the safe, efficient and long-life operation of the battery cell, and also providing a basis for the development of battery design, use and management system.

[0073] In some embodiments, the test parameter comprises a test state of charge, the second correspondence comprises a second correspondence between the leakage current and the test state of charge, and the decay acceleration coefficient comprises a state of charge acceleration coefficient.

[0074] For example, a first correspondence between the leakage current of the battery cell and the detection time under a plurality of test SOC is obtained; based on the first correspondence, a detection time corresponding to a leakage current stable state is determined; leakage currents of the battery cell corresponding to a plurality of test SOC at the detection time corresponding to the leakage current stable state are extracted to construct a second correspondence between the leakage current of the battery cell and the test SOC; and based on the second correspondence, a SOC acceleration coefficient is determined.

[0075] In this embodiment, by obtaining data of the leakage current of the battery cell changing with time under different SOC, the second correspondence between the leakage current of the battery cell and the SOC is established, and then the SOC acceleration coefficient can be quickly obtained, which provides an important parameter for subsequent construction of the life model of the battery, thereby improving the accuracy of the life prediction of the battery.

[0076] Those skilled in the art should understand that the SOC acceleration coefficient corresponds to the voltage acceleration coefficient, and the SOC acceleration coefficient can be converted into the voltage acceleration coefficient through certain derivation.

[0077] In some embodiments, the second correspondence is represented by a second fitting straight line in a second coordinate system, and the construction of the second correspondence between the leakage current of the battery cell and the test parameter comprises: constructing a second coordinate system with the leakage current as the vertical coordinate and the test state of charge as the horizontal coordinate; in the second coordinate system, the leakage currents of the battery cell corresponding to a plurality of test states of charge at the detection time corresponding to the leakage current stable state are linearly fitted to obtain the second fitting straight line.

[0078] For example, when the leakage current of the battery cell is in a stable state, after a plurality of groups of leakage current data under different SOC are obtained, a straight line is drawn in a second coordinate system with the leakage current as the vertical coordinate and the test SOC as the horizontal coordinate, so as to represent the second correspondence between the leakage current and the SOC through the straight line. The second correspondence between the leakage current and the SOC is represented by the fitting straight line in the coordinate system, which facilitates subsequent quick and intuitive determination of the SOC acceleration coefficient.

[0079] In some embodiments, based on the second correspondence, the decay acceleration coefficient is determined by determining a slope corresponding to the second fitting straight line as the state of charge acceleration coefficient.

[0080] For example, the SOC acceleration coefficient satisfies the formula I = ax soc +b, I represents the leakage current, x soc represents the SOC, the slope a represents the SOC acceleration coefficient, and b is the intercept value of the fitting straight line.

[0081] In this embodiment, the SOC acceleration coefficient is determined by calculating the slope of the fitting straight line representing the corresponding relationship between the leakage current and the SOC through linear fitting. The calculation process is simple, and a large amount of data is not required, thereby improving the efficiency of determining the SOC acceleration coefficient.

[0082] Figure 5 A schematic diagram of a method for obtaining a SOC acceleration coefficient of a battery cell according to one or more embodiments, the embodiment comprising steps S12-S42.

[0083] In step S12, a first corresponding relationship between the leakage current of the battery cell and the detection time under a plurality of test SOCs is obtained.

[0084] For example, as shown in Table 1, the SOC of the battery cell is set to 60%, 20%, and 5%, and then a constant temperature and constant voltage test is performed, wherein the voltage corresponding to 5% SOC is 3.138V, the voltage corresponding to 20% SOC is 3.25V, and the voltage corresponding to 60% SOC is 3.32V. The sampling interval is, for example, 10s, and the test period is, for example, 10 days, thereby obtaining continuous leakage current data under constant voltage state.

[0085] As shown in FIG. 6, a first corresponding relationship between the leakage current and the detection time under different SOCs according to one or more embodiments is shown, and in this embodiment, 60°C is taken as an example. In this figure, the horizontal axis is time, and the vertical axis is leakage current, with units of mA. Curve 5 corresponds to the data of the leakage current of the battery cell varying with time under 60% SOC; curve 6 corresponds to the data of the leakage current of the battery cell varying with time under 20% SOC; and curve 7 corresponds to the data of the leakage current of the battery cell varying with time under 5% SOC. Figure 6 Figure 6 In step S22, the detection time corresponding to the stable state of the leakage current is determined based on the first corresponding relationship.

[0086] For example, the 9th day is selected as the detection time corresponding to the stable state of the leakage current.

[0087] In step S321, the leakage current of the battery cell corresponding to a plurality of test states of charge at the detection time corresponding to the stable state of the leakage current is extracted, and a second coordinate system with the leakage current as the vertical axis and the test state of charge as the horizontal axis is constructed.

[0088] In step S322, the leakage current of the battery cell corresponding to a plurality of test states of charge at the detection time corresponding to the stable state of the leakage current is linearly fitted in the second coordinate system, and a second fitting straight line is obtained.

[0089] As shown in FIG. 7, a second fitting straight line representing the corresponding relationship between the leakage current and the test state of charge of the battery cell at the detection time corresponding to the stable state of the leakage current according to one or more embodiments is shown, and in this embodiment, 60°C is taken as an example. In this figure, the horizontal axis is the test state of charge, and the vertical axis is the leakage current, with units of mA. Curve 8 corresponds to the data of the leakage current of the battery cell varying with the test state of charge at the detection time corresponding to the stable state of the leakage current under 60°C.

[0090] As shown in FIG. 7, a second fitting straight line representing the corresponding relationship between the leakage current and the test state of charge of the battery cell at the detection time corresponding to the stable state of the leakage current according to one or more embodiments is shown, and in this embodiment, 60°C is taken as an example. In this figure, the horizontal axis is the test state of charge, and the vertical axis is the leakage current, with units of mA. Curve 8 corresponds to the data of the leakage current of the battery cell varying with the test state of charge at the detection time corresponding to the stable state of the leakage current under 60°C. Figure 7 Figure 7 ​​For the second corresponding relationship between the leakage current and the test SOC according to one or more embodiments, data is plotted and fitted in a second coordinate system with the leakage current I as the ordinate and the test state of charge SOC as the abscissa, to obtain a second fitted straight line C.

[0091] In step S42, the slope corresponding to the second fitted straight line is determined as the state of charge acceleration coefficient.

[0092] In this embodiment, the constant voltage test is performed on the battery cell at a plurality of set SOCs, the data of the leakage current changing with time at different SOCs is obtained, and then the stable current value is taken to establish the corresponding relationship between the leakage current and the SOC. The slope of the second fitted straight line is calculated, and then the SOC acceleration coefficient can be quickly determined.

[0093] Those skilled in the art can understand that in the above method of the specific embodiment, the writing order of each step does not mean 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.

[0094] The above is a schematic diagram of some embodiments of the method for obtaining the attenuation acceleration coefficient of the battery cell. Next, the system for obtaining the attenuation acceleration coefficient of the battery cell will be further introduced with reference to the accompanying drawings.

[0095] Figure 8 For the system for obtaining the attenuation acceleration coefficient of the battery cell according to one or more embodiments Figure 1 The system 8 for obtaining the attenuation acceleration coefficient of the battery cell includes a first determination module 81, a time determination module 82, a second determination module 83, and a coefficient determination module 84.

[0096] The first determination module 81 is configured to determine a first corresponding relationship between the leakage current of the battery cell and the detection time under a plurality of test values of the same test parameter.

[0097] In some embodiments, the test parameter includes a test temperature or a test SOC.

[0098] In some embodiments, the leakage current is determined by compensating the self-discharge current of the battery cell in a constant voltage manner.

[0099] The loss of electric quantity caused by the internal self-discharge of the battery cell is compensated in real time by an external constant voltage source, so that the voltage of the battery cell remains constant. At this time, the compensation current input from the outside is the self-discharge current of the battery cell, and the self-discharge current of the battery cell is also called the leakage current.

[0100] The time determination module 82 is configured to determine the detection time corresponding to the stable state of the leakage current based on the first corresponding relationship.

[0101] In some embodiments, the leakage current steady state includes that the difference of the leakage current of adjacent times is less than a threshold value.

[0102] The leakage current floats less over time, which indicates that the leakage current steady state.

[0103] The second determination module 83 is configured to extract the leakage current of the battery cell corresponding to the multiple test values at the detection time corresponding to the leakage current steady state, to construct the second correspondence between the leakage current and the test parameter of the battery cell.

[0104] In some embodiments, if the test parameter includes the test temperature, the second correspondence includes the second correspondence between the logarithmic value of the leakage current and the reciprocal of the test temperature.

[0105] In some other embodiments, if the test parameter includes the test state of charge, the second correspondence includes the second correspondence between the leakage current and the test state of charge.

[0106] The coefficient determination module 84 is configured to determine the attenuation acceleration coefficient based on the second correspondence.

[0107] In some embodiments, if the test parameter includes the test temperature, the attenuation acceleration coefficient includes the temperature acceleration coefficient.

[0108] In some other embodiments, if the test parameter includes the test state of charge, the attenuation acceleration coefficient includes the state of charge acceleration coefficient.

[0109] By using the principle of the leakage current of the battery cell, the first correspondence between the leakage current and the detection time is established, and the leakage current of the battery cell corresponding to the multiple test values at the detection time corresponding to the leakage current steady state is extracted, so that the second correspondence between the leakage current and the test parameter can be constructed, and the attenuation acceleration coefficient 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.

[0110] In some embodiments, the second correspondence is represented by a first fitting straight line in a first coordinate system, and the second determination module 83 is configured to construct a first coordinate system with the logarithmic value of the leakage current as the vertical coordinate and the reciprocal of the test temperature as the horizontal coordinate; and in the first coordinate system, the leakage current of the battery cell corresponding to the multiple test temperatures at the detection time corresponding to the leakage current steady state is linearly fitted to obtain the first fitting straight line.

[0111] In this embodiment, the second correspondence between the logarithmic value of the leakage current and the reciprocal of the test temperature is represented by the first fitting straight line, which facilitates subsequent intuitive and rapid determination of the temperature acceleration coefficient.

[0112] In some embodiments, the coefficient determination module 84 is configured to determine the slope of the first fitting straight line as the temperature acceleration coefficient.

[0113] In this embodiment, after obtaining the fitting straight line representing the relationship between the leakage current and the temperature through linear fitting, the temperature acceleration coefficient can be determined by calculating the slope of the fitting straight line. The calculation process is simple, and a large amount of data is not required, thus improving the efficiency of determining the temperature acceleration coefficient.

[0114] In some embodiments, Figure 9 A schematic diagram of a system for obtaining the attenuation acceleration coefficient of an electric core according to one or more embodiments Figure 2 The system for obtaining the attenuation acceleration coefficient of an electric core further includes a boundary determination module 91 configured to determine the temperature boundary of the electric core according to the discrete points in the first fitting straight line.

[0115] For example, if a certain temperature deviates from the trend of other temperatures, it indicates that the temperature has affected the normal attenuation mechanism of the electric core, and thus the temperature boundary of the electric core can be confirmed. By quickly determining the temperature boundary of the electric core, the safety risk of the electric core can be reduced, and thermal runaway can be prevented, thus providing support for ensuring the safe, efficient, and long-life operation of the electric core, and serving as a basis for the development of battery design, use, and management systems.

[0116] In some embodiments, the second relationship is represented by a second fitting straight line in a second coordinate system, and the second determination module 83 is configured to construct a second coordinate system with the leakage current as the vertical coordinate and the test state of charge as the horizontal coordinate; in the second coordinate system, the leakage currents of the electric core corresponding to a plurality of test states of charge at the detection time of the stable state of the leakage current are linearly fitted to obtain the second fitting straight line.

[0117] The second relationship between the leakage current and the SOC is represented by the fitting straight line in the coordinate system, which facilitates the subsequent quick and intuitive determination of the SOC acceleration coefficient.

[0118] In some embodiments, the coefficient determination module 84 is configured to determine the slope of the second fitting straight line as the state of charge acceleration coefficient.

[0119] In this embodiment, after obtaining the fitting straight line representing the relationship between the leakage current and the SOC through linear fitting, the SOC acceleration coefficient can be determined by calculating the slope of the fitting straight line. The calculation process is simple, and a large amount of data is not required, thus improving the efficiency of determining the SOC acceleration coefficient.

[0120] Figure 10 A schematic diagram of a system for obtaining the attenuation acceleration coefficient of an electric core according to one or more embodiments Figure 3The system for obtaining the attenuation acceleration coefficient of the battery cell can be implemented by means of an electronic device. The system 8 for obtaining the attenuation acceleration coefficient of the battery cell comprises a memory 1010 and a processor 1020. The memory 1010 can be a disk, a 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 a microcontroller. The processor 1020 is used to execute the instructions stored in the memory.

[0121] In some embodiments, the processor 1020 is coupled to the memory 1010 through a BUS 1030. The system 8 for obtaining the attenuation acceleration coefficient of the battery cell can also be connected to an external storage device 1050 through a storage interface 1040 to call external data, and can also be connected to a network or another computer system (not shown) through a network interface 1060. Details are not described here.

[0122] In this embodiment, the data instructions are stored in the memory, and the above instructions are processed by the processor, so that the efficiency and accuracy of obtaining the attenuation acceleration coefficient of the battery cell are improved, thereby facilitating subsequent rapid and accurate prediction of the battery life.

[0123] In other embodiments, the present application provides a computer readable storage medium having computer program instructions stored thereon, which instructions, when executed by a processor, implement the steps of the method in the above embodiments. Those skilled in the art should understand that the embodiments of the present application can be provided as a method, an apparatus or a computer program product. Therefore, the present application can be in the form of a complete hardware embodiment, a complete software embodiment or an embodiment combining software and hardware aspects. Moreover, the present application can be in the form of a computer program product implemented 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.

[0124] In some embodiments of the application, a computer program product is also provided, comprising computer program instructions which, when executed by a processor, implement the method of any one of the above embodiments.

[0125] The above description of each embodiment tends to emphasize the differences between the embodiments, and the same or similar parts can be referred to each other. For the sake of brevity, the same or similar parts are not described here.

[0126] So far, the present application has been described in detail. In order not to obscure the concept of the present application, some details known in the art are not described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein according to the above description.

[0127] The methods and systems of the present application can be implemented in a number of ways. For example, the methods and systems of the present application can be implemented via software, hardware, firmware, or any combination of software, hardware, and firmware. The above described order of steps for the methods is merely illustrative and the steps of the methods of the present application are not limited to the order specifically described above unless otherwise specifically stated. Furthermore, in some embodiments, the present application can also be implemented as a program recorded on a recording medium, which includes machine readable instructions for implementing the methods according to the present application. Thus, the present application also covers a recording medium storing a program for executing the methods according to the present application.

[0128] While certain specific embodiments of the present application have been described in detail herein, it should be understood that the examples are merely illustrative of the present application and are not intended to limit the scope of the application. The skilled artisan will understand that modifications can be made in the above embodiments without departing from the scope and spirit of the application. The scope of the present application is defined by the appended claims.

Claims

1. A method of obtaining a decay acceleration coefficient of a battery cell, the method comprising: The method comprises: determining a first correspondence between the leakage current of the battery and the detection time under a plurality of test values of a same test parameter; determining, based on the first correspondence, a detection time corresponding to a leakage current stable state, the leakage current stable state comprising a difference between leakage currents of adjacent times being less than a threshold value; extracting, under the detection time corresponding to the leakage current stable state, the leakage current of the battery corresponding to the plurality of test values to construct a second correspondence between the leakage current of the battery and the test parameter; determining, based on the second correspondence, a decay acceleration coefficient.

2. The method of obtaining the attenuation acceleration coefficient of an electric core according to claim 1, characterized in that, The test parameter comprises a test temperature, the second correspondence comprises a second correspondence between a logarithmic value of the leakage current and an inverse of the test temperature, and the decay acceleration coefficient comprises a temperature acceleration coefficient.

3. The method of obtaining the attenuation acceleration coefficient of an electric core according to claim 2, characterized in that, The second correspondence is represented by a first fitting straight line in a first coordinate system, and the constructing of the second correspondence between the leakage current of the battery and the test parameter comprises: constructing the first coordinate system with the logarithmic value of the leakage current as the ordinate and the inverse of the test temperature as the abscissa; in the first coordinate system, linearly fitting the logarithmic value of the leakage current corresponding to the inverse of the plurality of test temperatures under the detection time corresponding to the leakage current stable state to obtain the first fitting straight line.

4. The method of obtaining the attenuation acceleration coefficient of the electric core according to claim 3, characterized in that, The determining of the decay acceleration coefficient based on the second correspondence comprises: determining the slope of the first fitting straight line as the temperature acceleration coefficient.

5. The method of obtaining the attenuation acceleration coefficient of an electric core according to claim 3, wherein, The method further comprises: determining a temperature boundary used by the battery according to discrete points in the first fitting straight line.

6. The method of obtaining the attenuation acceleration coefficient of an electrically charged cell of claim 1, wherein, The test parameter comprises a test state of charge, the second correspondence comprises a second correspondence between the leakage current and the test state of charge, and the decay acceleration coefficient comprises a state of charge acceleration coefficient.

7. The method of obtaining the attenuation acceleration coefficient of an electric core according to claim 6, characterized in that, The second correspondence is represented by a second fitting straight line in a second coordinate system, and the constructing of the second correspondence between the leakage current of the battery and the test parameter comprises: constructing the 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 corresponding to the plurality of test states of charge under the detection time corresponding to the leakage current stable state to obtain the second fitting straight line.

8. The method of obtaining the attenuation acceleration coefficient of an electric core according to claim 7, wherein, The determining of the decay acceleration coefficient based on the second correspondence comprises: determining the slope of the second fitting straight line as the state of charge acceleration coefficient.

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

10. A system for obtaining a decay acceleration coefficient of a battery cell, the system comprising: The method comprises: a first determining module configured to determine a first correspondence between the leakage current of the battery and the detection time under a plurality of test values of a same test parameter; a time determining module configured to determine, based on the first correspondence, a detection time corresponding to a leakage current stable state, the leakage current stable state comprising a difference between leakage currents of adjacent times being less than a threshold value; a second determining module configured to extract, under the detection time corresponding to the leakage current stable state, the leakage current of the battery corresponding to the plurality of test values to construct a second correspondence between the leakage current of the battery and the test parameter; A coefficient determination module configured to determine the attenuation acceleration coefficient based on the second correspondence.

11. A system for obtaining a decay acceleration factor for a battery cell, the system comprising: The method comprises: 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 of acquiring the attenuation acceleration coefficient of the battery cell according to any one of claims 1 to 9.

12. A computer readable storage medium having stored thereon computer instructions, wherein, The computer instructions, when executed by the processor, implement the method of acquiring the attenuation acceleration coefficient of the battery cell according to any one of claims 1 to 9.

13. A computer program product, characterised in that, The method comprises: The computer instructions, when executed by the processor, implement the method of acquiring the attenuation acceleration coefficient of the battery cell according to any one of claims 1 to 9.

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