Method for obtaining entropy heat coefficient of lithium ion battery, terminal device and medium

Abstract

This invention relates to the field of lithium-ion battery technology and provides a method, terminal device, and medium for obtaining the entropy-thermal coefficient of a lithium-ion battery. The method includes: acquiring the measured voltage and voltage measurement error of the lithium-ion battery at different time periods; wherein the lithium-ion battery is placed under different ambient temperatures at different time periods; correcting the battery voltage at each time period based on the measured voltage and voltage measurement error; and calculating the entropy-thermal coefficient of the lithium-ion battery based on the correlation between battery voltage and ambient temperature. This invention achieves automatic correction of the background of entropy-thermal coefficient measurement, reducing the impact of phenomena such as battery self-discharge on the accuracy of voltage measurement; simultaneously, it ensures that the correlation between battery voltage and ambient temperature with smaller errors can more accurately calculate the entropy-thermal coefficient of the lithium-ion battery, thereby improving the success rate and accuracy of entropy-thermal coefficient testing.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery technology, and particularly relates to a method for obtaining the entropy thermal coefficient of a lithium-ion battery, a terminal device, and a computer-readable storage medium. Background Technology

[0002] With the continuous development of lithium-ion battery technology, lithium-ion batteries have been more widely used in the electric vehicle field. Consequently, users have increasingly higher requirements for the safety performance of lithium-ion batteries. Since heat generation during the charging and discharging process of lithium-ion batteries is a significant factor contributing to battery safety issues, battery heat generation is a key focus for researchers. Battery heat generation consists of three main parts: ohmic heat, reaction heat, and polarization heat. The entropy coefficient is an important parameter characterizing the reaction heat of lithium-ion batteries.

[0003] In existing technologies, the commonly used method for measuring entropy-thermal coefficient is the potentiometric method. However, when measuring the entropy-thermal coefficient based on the potentiometric method, the battery needs to be allowed to rest for a sufficiently long time to reach equilibrium (generally no less than 24 hours), i.e., it must first undergo a relaxation process. During the programmed temperature control process, the lithium battery also needs to be kept warm to ensure the battery voltage balance. Furthermore, even if the battery is kept warm for a sufficiently long time, if the battery exhibits self-discharge, it will still lead to unstable battery voltage, thereby reducing the accuracy of the entropy-thermal coefficient measurement. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a method for obtaining the entropy thermal coefficient of a lithium-ion battery, a terminal device, and a computer-readable storage medium to solve the problem of low accuracy in the measurement of the entropy thermal coefficient in the prior art.

[0005] A first aspect of this invention provides a method for obtaining the entropy thermal coefficient of a lithium-ion battery, comprising:

[0006] The measurement voltage and voltage measurement error of the lithium-ion battery are obtained at different time periods; wherein the lithium-ion battery is placed under different ambient temperatures at different time periods.

[0007] The battery voltage of the lithium-ion battery in each of the time periods is corrected based on the measured voltage and the voltage measurement error.

[0008] Based on the relationship between the battery voltage and the ambient temperature, the entropy thermal coefficient of the lithium-ion battery is calculated.

[0009] A second aspect of the present invention provides an apparatus for obtaining the entropy thermal coefficient of a lithium-ion battery, comprising:

[0010] The first acquisition unit is used to acquire the measured voltage and voltage measurement error of the lithium-ion battery at different time periods; wherein the lithium-ion battery is placed under different ambient temperatures at different time periods.

[0011] A calibration unit is used to correct the battery voltage of the lithium-ion battery in each of the time periods based on the measured voltage and the voltage measurement error.

[0012] The calculation unit is used to calculate the entropy-thermal coefficient of the lithium-ion battery based on the relationship between the battery voltage and the ambient temperature.

[0013] A third aspect of the present invention provides a terminal device, including a memory and a processor, wherein the memory stores a computer program that can run on the processor, and the processor executes the computer program to implement the steps of the method for obtaining the entropy thermal coefficient of a lithium-ion battery as described above.

[0014] A fourth aspect of the present invention provides a computer-readable storage medium storing a computer program, wherein a processor executes the computer program to implement the steps of the method for obtaining the entropy thermal coefficient of a lithium-ion battery as described above.

[0015] In this embodiment of the invention, by placing the lithium-ion battery at different ambient temperatures at different time periods, the measured voltage and voltage measurement error of the lithium-ion battery at each time period are obtained. Based on the measured voltage and voltage measurement error, the battery voltage at each time period can be corrected, realizing automatic correction of the background of entropy thermal coefficient measurement and reducing the impact of phenomena such as battery self-discharge on the accuracy of voltage measurement. At the same time, it ensures that the correspondence between battery voltage and ambient temperature with small error can be calculated more accurately, thereby improving the success rate and accuracy of entropy thermal coefficient testing. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart illustrating the implementation of the method for obtaining the entropy thermal coefficient of a lithium-ion battery according to an embodiment of the present invention.

[0018] Figure 2This is a flowchart illustrating the specific implementation of the method S103 for obtaining the entropy thermal coefficient of a lithium-ion battery provided in this embodiment of the invention.

[0019] Figure 3 This is a flowchart illustrating the implementation of a method for obtaining the entropy thermal coefficient of a lithium-ion battery according to another embodiment of the present invention.

[0020] Figure 4 This is a graph showing the relationship between ambient temperature T and time t for a lithium-ion battery, as provided in an embodiment of the present invention.

[0021] Figure 5 This is a flowchart illustrating the specific implementation of the method S101 for obtaining the entropy thermal coefficient of a lithium-ion battery provided in this embodiment of the invention.

[0022] Figure 6 This is a structural block diagram of the device for obtaining the entropy thermal coefficient of a lithium-ion battery provided in an embodiment of the present invention;

[0023] Figure 7 This is a schematic diagram of a terminal device provided in an embodiment of the present invention. Detailed Implementation

[0024] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0025] To illustrate the technical solution described in this invention, specific embodiments are described below.

[0026] Figure 1 The implementation flow of the method for obtaining the entropy thermal coefficient of a lithium-ion battery provided by an embodiment of the present invention is shown. The above method flow includes steps S101 to S103. The specific implementation principle of each step is as follows:

[0027] S101: Obtain the measured voltage and voltage measurement error of the lithium-ion battery at different time periods; wherein the lithium-ion battery is placed under different ambient temperatures at different time periods.

[0028] A lithium-ion battery is a type of lithium battery that does not contain metallic lithium and is rechargeable. A lithium-ion battery consists of a positive electrode, a negative electrode, a separator, and an electrolyte. The positive and negative electrodes are immersed in the electrolyte, and lithium ions move between the positive and negative electrodes using the electrolyte as a medium, thus enabling the battery to charge and discharge.

[0029] In this embodiment of the invention, in order to determine the entropy thermal coefficient of a pre-selected lithium-ion battery, the lithium-ion battery is placed at different ambient temperatures using a constant temperature chamber during multiple different time periods. These multiple different time periods are consecutive and their durations can be the same or different.

[0030] For example, each hour in a continuous ten-hour period is a preset time period. In the first hour, the ambient temperature of the lithium-ion battery is set to 22 degrees Celsius; in the second hour, the ambient temperature of the lithium-ion battery is set to 24 degrees Celsius.

[0031] Within each time period, the lithium-ion battery is placed at the corresponding ambient temperature, and the measured voltage and voltage measurement error of the lithium-ion battery during that time period are obtained. Specifically, the lithium-ion battery is placed in a constant temperature chamber matched to the aforementioned ambient temperature and connected to an Arbin charge-discharge instrument to allow the lithium-ion battery to reach a preset state of charge and then be left to stand. For example, the lithium-ion battery is left to stand after reaching a state of charge of 50%. The voltage of the lithium-ion battery is collected according to a preset sampling frequency. If the voltage of the lithium-ion battery is detected to have stabilized, the stabilized voltage is recorded, and this voltage is determined as the measured voltage of the lithium-ion battery in the current time period.

[0032] In this embodiment of the invention, in order to facilitate the distinction between the voltage actually acquired and the voltage obtained after subsequent numerical correction processing, the voltage actually acquired is referred to as the measured voltage; and the voltage obtained after subsequent numerical correction processing is referred to as the battery voltage.

[0033] S102: Based on the measured voltage and the voltage measurement error, the battery voltage of the lithium-ion battery is corrected for each of the time periods.

[0034] For each time period during the change of ambient temperature, the difference between the test voltage collected during that time period and the voltage measurement error is calculated, and the difference is output as the battery voltage for that time period. This eliminates the noise impact on the lithium-ion battery caused by self-discharge during the entropy thermal coefficient test, and realizes the battery voltage correction of the lithium-ion battery.

[0035] S103: Calculate the entropy thermal coefficient of the lithium-ion battery based on the relationship between the battery voltage and the ambient temperature.

[0036] As an embodiment of the present invention Figure 2 The specific implementation flow of the method S103 for obtaining the entropy thermal coefficient of a lithium-ion battery provided in an embodiment of the present invention is shown below:

[0037] S1031: Render a data point in a Cartesian coordinate system based on each ambient temperature and its corresponding battery voltage.

[0038] S1032: Using a preset fitting algorithm, perform linear fitting on each of the data points and obtain the slope of the fitted line.

[0039] S1033: Output the slope as the entropy-thermal coefficient of the lithium-ion battery.

[0040] In this embodiment of the invention, a rectangular coordinate system is created with ambient temperature as the horizontal axis unit and the corrected battery voltage as the vertical axis unit.

[0041] For each of the above-mentioned time points, the test voltage of the lithium-ion battery is corrected based on S101 and S102 to obtain the battery voltage. Then, the ambient temperature corresponding to that time point is read. The ambient temperature T is used as the x-coordinate of data point a, and the battery voltage U is used as the y-coordinate of data point a. Based on the x-coordinate and y-coordinate of data point a, data point a is rendered in a Cartesian coordinate system. Similarly, various data points associated with different ambient temperatures and battery voltages can be rendered in a Cartesian coordinate system.

[0042] In this embodiment of the invention, a linear equation y=kx+b (where k and b are integers greater than zero) is used to fit a straight line to each data point in a rectangular coordinate system to determine the slope b in the equation. The fitting algorithm can be, for example, linear regression or least squares.

[0043] Since the entropy-thermal coefficient of a lithium-ion battery is used to represent the rate of change of the battery voltage with temperature, the slope b of the linear equation in the above UT rectangular coordinate system is output as the entropy-thermal coefficient of the lithium-ion battery.

[0044] In this embodiment of the invention, by placing the lithium-ion battery at different ambient temperatures at different time periods, the measured voltage and voltage measurement error of the lithium-ion battery at each time period are obtained. Based on the measured voltage and voltage measurement error, the battery voltage at each time period can be corrected, realizing automatic correction of the background of entropy thermal coefficient measurement and reducing the impact of phenomena such as battery self-discharge on the accuracy of voltage measurement. At the same time, it ensures that the correspondence between battery voltage and ambient temperature with small error can be calculated more accurately, thereby improving the success rate and accuracy of entropy thermal coefficient testing.

[0045] To further explain the above-mentioned process of ambient temperature change, as another embodiment of the present invention, Figure 3The implementation flow of the method for obtaining the entropy thermal coefficient of a lithium-ion battery provided in an embodiment of the present invention is illustrated. For example... Figure 3 As shown, prior to S101 above, it also includes:

[0046] S104: Obtain a preset program temperature control list, which contains multiple experimental temperatures.

[0047] In this embodiment of the invention, a pre-entered programmable temperature control list is loaded, which contains multiple experimental temperatures arranged in sequence. Specifically, during the experimental phase, when it is necessary to collect the measurement voltage of the lithium-ion battery, the ambient temperature must meet the aforementioned experimental temperature.

[0048] S105: Read each experimental temperature in the program temperature control list in sequence, and perform temperature control steps for each experimental temperature until all experimental temperatures in the program temperature control list have been read.

[0049] The temperature control steps include:

[0050] The lithium-ion battery is placed at the read experimental temperature. If the lithium-ion battery is detected to meet the preset conditions, the ambient temperature of the lithium-ion battery is restored from the experimental temperature to the preset reference temperature until the lithium-ion battery is detected to meet the preset conditions again below the reference temperature.

[0051] The preset conditions include: the lithium-ion battery reaching an equilibrium state or the lithium-ion battery being left to stand for a preset period of time.

[0052] Each experimental temperature from the above-mentioned programmable temperature control list is sequentially retrieved. For the currently retrieved experimental temperature, the temperature of the constant temperature chamber is adjusted to that experimental temperature so that the lithium-ion battery in the constant temperature chamber can be placed at that experimental temperature. Afterwards, by connecting the Arbin charge / discharge device, the lithium-ion battery is allowed to reach a preset state of charge and then left to stand. In this embodiment of the invention, when the ambient temperature changes, the built-in timer is reset and a timing operation is triggered.

[0053] The voltage of the lithium-ion battery is collected according to a preset sampling frequency. If the voltage of the lithium-ion battery is detected to have reached a stable state, it is determined that the lithium-ion battery has reached an equilibrium state. At this point, the ambient temperature of the lithium-ion battery is restored from the experimental temperature to the preset reference temperature.

[0054] If the lithium-ion battery has not reached equilibrium, keep the temperature of the constant temperature chamber constant and let the lithium-ion battery continue to stand for a sufficient time until the timer value reaches the preset duration or the lithium-ion battery reaches equilibrium. Then, restore the ambient temperature of the lithium-ion battery from the experimental temperature to the preset reference temperature.

[0055] The aforementioned preset duration can be automatically determined using highly intelligent experimental instruments, or it can be determined based on pre-obtained experimental data. For example, prior to step S104, under the same environmental parameters as in subsequent step S104, the lithium-ion battery is placed in a constant-temperature chamber, and its voltage is continuously monitored at a constant temperature. The test duration taken for the battery voltage to stabilize is recorded, and this test duration is determined as the preset duration in the aforementioned preset conditions.

[0056] Preferably, the preset duration can be set to any value between 1 and 3 hours.

[0057] Preferably, the reference temperature is the ambient temperature at which the lithium-ion battery is used in the actual production environment, typically 25°C.

[0058] At the reference temperature, based on the same implementation principle described above, the voltage of the lithium-ion battery is collected at a preset sampling frequency. If the lithium-ion battery is detected to have reached equilibrium again or the timer's timing value reaches the preset duration, the process returns to step S105 to read the next experimental temperature from the program temperature control list and perform temperature adjustment again for that experimental temperature, until every experimental temperature in the program temperature control list has been read.

[0059] For ease of understanding, Figure 4 The diagram shows the relationship between ambient temperature T and time t for the lithium-ion battery provided in the embodiment of the present invention. Figure 4 The corresponding diagram shown includes five time periods of equal duration. The first, third, and fifth time periods correspond to the same ambient temperature T, which is the aforementioned preset reference temperature. The second and fourth time periods correspond to two experimental temperatures appearing sequentially in the program temperature control list. Therefore, in the ambient temperature control method provided by this embodiment of the invention, after each time period's voltage test of the lithium-ion battery according to the experimental temperature is completed, the ambient temperature first returns to the reference temperature, and then in the next time period, the ambient temperature is adjusted to the next experimental temperature in the program temperature control list.

[0060] It is worth noting that, since different lithium-ion batteries may have different materials and volumes, the time required for different parts of a lithium-ion battery to reach equilibrium at a specified ambient temperature will also be different. Therefore, the duration of each time period corresponding to each of the above-mentioned ambient temperatures may be the same or different.

[0061] As an embodiment of the present invention Figure 5The specific implementation flow of the method S101 for obtaining the entropy thermal coefficient of a lithium-ion battery provided in an embodiment of the present invention is shown below:

[0062] S1011: Obtain the measured voltage of the lithium-ion battery at various time periods, wherein the time periods include a first time period corresponding to the reference temperature and a second time period corresponding to the experimental temperature.

[0063] In this embodiment of the invention, the time periods during which the ambient temperature is set to a reference temperature are referred to as the first time period; the time periods during which the ambient temperature is set to the experimental temperature in the programmable temperature control list are referred to as the second time period. Figure 4 It can be seen that the first time period and the second time period alternate.

[0064] Within each time period, when the lithium-ion battery is detected to have reached an equilibrium state, the measured voltage of the lithium-ion battery during that time period is obtained.

[0065] S1012: Perform data fitting on the measured voltages within each of the first time periods to obtain a fitting function.

[0066] In this embodiment of the invention, a scatter plot is generated, using the acquisition time t (seconds) of the measured voltage within a first time period as the abscissa and the voltage value U (volts) of the measured voltage as the ordinate, to show the relationship between the measured voltage U and the acquisition time t. By using a preset function expression, each scatter point (t, U) in the scatter plot is fitted to obtain the relationship between the measured voltage U and the acquisition time t: U=f(t).

[0067] The preset function expressions mentioned above include, but are not limited to, power functions, exponential functions, and logarithmic functions.

[0068] For example, if the above-mentioned preset function expression is a power function based on a six-term formula, U = a + bt + ct 2 +dt 3 +et 4 +ft 5 +gt 6 =f(t), then we only need to substitute the abscissa t and ordinate U of each scatter point into the power function based on the six terms in the scatter plot of the relationship between the measured voltage U and the acquisition time t. Through mathematical fitting, we can calculate the constant coefficients a, b, c, d, e, f and g in the power function, and thus output the fitting function U = f(t) corresponding to the scatter plot.

[0069] S1013: Based on the fitting function, calculate the voltage measurement error of the lithium-ion battery in each of the second time periods.

[0070] In this embodiment of the invention, the time t contained in the second time period is input into the above-mentioned fitting function U = f(t) to calculate the noise voltage U generated during the entire test process. The noise voltage U is the voltage measurement error of lithium-ion electrons in the second time period.

[0071] Because the relaxation time of lithium-ion batteries is very long during the traditional test of the entropy thermal coefficient, this embodiment of the invention calculates the voltage measurement error of the lithium-ion battery in various time periods and introduces background correction for the battery voltage. The reference temperature is restored in both the time periods before and after the programmed temperature control, making the test process of the entropy thermal coefficient of lithium-ion batteries easier, shortening the relaxation time and test time, and thus improving the test efficiency of the entropy thermal coefficient.

[0072] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0073] Corresponding to the method for obtaining the entropy thermal coefficient of a lithium-ion battery provided in the embodiments of the present invention, Figure 6 A structural block diagram of the apparatus for obtaining the entropy-thermal coefficient of a lithium-ion battery according to an embodiment of the present invention is shown. For ease of explanation, only the parts relevant to this embodiment are shown.

[0074] Reference Figure 6 The device includes:

[0075] The first acquisition unit 61 is used to acquire the measured voltage and voltage measurement error of the lithium-ion battery at different time periods; wherein the lithium-ion battery is placed under different ambient temperatures at different time periods.

[0076] The correction unit 62 is used to correct the battery voltage of the lithium-ion battery in each time period according to the measured voltage and the voltage measurement error.

[0077] The calculation unit 63 is used to calculate the entropy thermal coefficient of the lithium-ion battery based on the relationship between the battery voltage and the ambient temperature.

[0078] Optionally, the device for obtaining the entropy thermal coefficient of the lithium-ion battery further includes:

[0079] The second acquisition unit is used to acquire a preset program temperature control list, which contains multiple experimental temperatures.

[0080] The temperature control unit is used to sequentially read each of the experimental temperatures in the program temperature control list, and perform temperature regulation steps for each experimental temperature until all the experimental temperatures in the program temperature control list have been read.

[0081] Specifically, the temperature control unit is used for:

[0082] The lithium-ion battery is placed at the read experimental temperature. If the lithium-ion battery is detected to have reached an equilibrium state, the ambient temperature of the lithium-ion battery is restored from the experimental temperature to a preset reference temperature until the lithium-ion battery is detected to have reached an equilibrium state below the reference temperature.

[0083] Optionally, the first acquisition unit 61 includes:

[0084] The acquisition subunit is used to acquire the measured voltage of the lithium-ion battery at various time periods, including a first time period corresponding to the reference temperature and a second time period corresponding to the experimental temperature.

[0085] The first fitting subunit is used to fit the measured voltages within each of the first time periods to obtain a fitting function.

[0086] The first calculation subunit is used to calculate the voltage measurement error of the lithium-ion battery in each of the second time periods based on the fitting function.

[0087] Optionally, the computing unit 63 includes:

[0088] The rendering subunit is used to render a data point in a Cartesian coordinate system based on each ambient temperature and its corresponding battery voltage.

[0089] The second fitting subunit is used to perform linear fitting on each of the data points using a preset fitting algorithm and to obtain the slope of the fitted line.

[0090] The output subunit is used to output the slope as the entropy-thermal coefficient of the lithium-ion battery.

[0091] Optionally, the correction unit 62 includes:

[0092] The second calculation subunit calculates the difference between the measured voltage and the voltage measurement error for each time period, and outputs the difference as the battery voltage for that time period.

[0093] In this embodiment of the invention, by placing the lithium-ion battery at different ambient temperatures at different time periods, the measured voltage and voltage measurement error of the lithium-ion battery at each time period are obtained. Based on the measured voltage and voltage measurement error, the battery voltage at each time period can be corrected, realizing automatic correction of the background of entropy thermal coefficient measurement and reducing the impact of phenomena such as battery self-discharge on the accuracy of voltage measurement. At the same time, it ensures that the correspondence between battery voltage and ambient temperature with small error can be calculated more accurately, thereby improving the success rate and accuracy of entropy thermal coefficient testing.

[0094] Figure 7 This is a schematic diagram of a terminal device provided in an embodiment of the present invention. Figure 7 As shown, the terminal device 7 in this embodiment includes: a processor 70, a memory 71, and a computer program 72 stored in the memory 71 and executable on the processor 70, such as an image capturing program. When the processor 70 executes the computer program 72, it implements the steps in the various image capturing method embodiments described above, for example... Figure 1 Steps 101 to 103 are shown. Alternatively, when the processor 70 executes the computer program 72, it implements the functions of each module / unit in the above-described device embodiments, for example... Figure 6 The functions of units 61 to 63 are shown.

[0095] For example, the computer program 72 may be divided into one or more modules / units, which are stored in the memory 71 and executed by the processor 70 to complete the present invention. The one or more modules / units may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program 72 in the terminal device 7.

[0096] The terminal device 7 can be a desktop computer, laptop, handheld computer, or cloud server, etc. The terminal device may include, but is not limited to, a processor 70 and a memory 71. Those skilled in the art will understand that... Figure 7 This is merely an example of terminal device 7 and does not constitute a limitation on terminal device 7. It may include more or fewer components than shown, or combine certain components, or different components. For example, the terminal device may also include input / output devices, network access devices, buses, etc.

[0097] The processor 70 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0098] The memory 71 can be an internal storage unit of the terminal device 7, such as a hard disk or memory of the terminal device 7. The memory 71 can also be an external storage device of the terminal device 7, such as a plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card equipped on the terminal device 7. Furthermore, the memory 71 can include both internal and external storage units of the terminal device 7. The memory 71 is used to store the computer program and other programs and data required by the terminal device. The memory 71 can also be used to temporarily store data that has been output or will be output.

[0099] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0100] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0101] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for obtaining the entropy thermal coefficient of a lithium-ion battery, characterized in that, include: The measurement voltage and voltage measurement error of the lithium-ion battery are obtained at different time periods; wherein the lithium-ion battery is placed under different ambient temperatures at different time periods. The battery voltage of the lithium-ion battery in each of the time periods is corrected based on the measured voltage and the voltage measurement error. Based on the relationship between the battery voltage and the ambient temperature, the entropy-thermal coefficient of the lithium-ion battery is calculated. Before obtaining the measured voltage and voltage measurement error of the lithium-ion battery at different time periods, the method further includes: obtaining a preset program temperature control list, which contains multiple experimental temperatures; sequentially reading each experimental temperature in the program temperature control list and performing temperature regulation for each experimental temperature, until all experimental temperatures in the program temperature control list have been read. The step of obtaining the measured voltage and voltage measurement error of the lithium-ion battery at different time periods includes: obtaining the measured voltage of the lithium-ion battery at different time periods, wherein the time periods include a first time period corresponding to a preset reference temperature and a second time period corresponding to the experimental temperature; performing data fitting on the measured voltage in each of the first time periods to obtain a fitting function; and calculating the voltage measurement error of the lithium-ion battery in each of the second time periods based on the fitting function. The step of correcting the battery voltage of the lithium-ion battery in each time period based on the measured voltage and the voltage measurement error includes: calculating the difference between the measured voltage and the voltage measurement error in each time period, and outputting the difference as the battery voltage for that time period.

2. The method for obtaining the entropy thermal coefficient of a lithium-ion battery as described in claim 1, characterized in that, The temperature control steps include: The lithium-ion battery is placed at the read experimental temperature. If the lithium-ion battery is detected to meet the preset conditions, the ambient temperature of the lithium-ion battery is restored from the experimental temperature to the preset reference temperature until the lithium-ion battery is detected to meet the preset conditions again below the reference temperature. The preset conditions include: the lithium-ion battery reaching an equilibrium state or the lithium-ion battery being left to stand for a preset period of time.

3. The method for obtaining the entropy thermal coefficient of a lithium-ion battery as described in claim 1, characterized in that, The calculation of the entropy-thermal coefficient of the lithium-ion battery based on the relationship between the battery voltage and the ambient temperature includes: Render a data point in a Cartesian coordinate system based on each ambient temperature and its corresponding battery voltage; Using a preset fitting algorithm, a straight line is fitted to each of the data points, and the slope of the fitted line is obtained. The slope is output as the entropy-thermal coefficient of the lithium-ion battery.

4. A device for obtaining the entropy thermal coefficient of a lithium-ion battery, characterized in that, include: The first acquisition unit is used to acquire the measured voltage and voltage measurement error of the lithium-ion battery at different time periods; wherein the lithium-ion battery is placed under different ambient temperatures at different time periods. A calibration unit is used to correct the battery voltage of the lithium-ion battery in each of the time periods based on the measured voltage and the voltage measurement error. A calculation unit is used to calculate the entropy-thermal coefficient of the lithium-ion battery based on the relationship between the battery voltage and the ambient temperature. The second acquisition unit is used to acquire a preset program temperature control list, which contains multiple experimental temperatures; The temperature control unit is used to sequentially read each of the experimental temperatures in the program temperature control list, and perform temperature regulation steps for each of the experimental temperatures until all the experimental temperatures in the program temperature control list have been read. The first acquisition unit includes: an acquisition subunit, configured to acquire the measured voltage of the lithium-ion battery in various time periods, wherein the time periods include a first time period corresponding to a reference temperature and a second time period corresponding to the experimental temperature; a first fitting subunit, configured to perform data fitting on the measured voltage in each of the first time periods to obtain a fitting function; and a first calculation subunit, configured to calculate the voltage measurement error of the lithium-ion battery in each of the second time periods based on the fitting function. The correction unit includes a second calculation subunit, used to calculate the difference between the measured voltage and the voltage measurement error for each time period, and output the difference as the battery voltage for that time period.

5. The apparatus for obtaining the entropy thermal coefficient of a lithium-ion battery as described in claim 4, characterized in that, The temperature control unit is specifically used for: The lithium-ion battery is placed at the read experimental temperature. If the lithium-ion battery is detected to meet the preset conditions, the ambient temperature of the lithium-ion battery is restored from the experimental temperature to the preset reference temperature until the lithium-ion battery is detected to meet the preset conditions again below the reference temperature. The preset conditions include: the lithium-ion battery reaching an equilibrium state or the lithium-ion battery being left to stand for a preset period of time.

6. A terminal device, comprising a memory and a processor, wherein the memory stores a computer program executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method as described in any one of claims 1 to 3.

7. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1 to 3.

Images