A method for measuring internal temperature of a lithium ion battery, readable storage medium, electronic device and apparatus

Abstract

The application provides a method for measuring the internal temperature of a lithium ion battery, a readable storage medium, an electronic device and an apparatus. The method sets an internal reference temperature of the lithium ion battery, acquires first electrochemical impedance spectrum data at the internal reference temperature and second electrochemical impedance spectrum data at an unknown internal temperature; performs a subtraction operation on the second electrochemical impedance spectrum data and the first electrochemical impedance spectrum data to obtain an electrochemical impedance spectrum data difference function; calculates an extreme point of the electrochemical impedance spectrum data difference function to obtain the abscissa of the extreme point, and substitutes the abscissa of the extreme point into an Arrhenius formula to calculate the unknown internal temperature. The technical scheme provided by the application accurately calculates the unknown internal temperature of the lithium ion battery through the electrochemical impedance spectrum data at the internal reference temperature and the unknown internal temperature, monitors the internal temperature of the lithium ion battery and responds in a timely manner, and reduces the use risk of the lithium ion battery.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of lithium ion battery detection, and in particular to a method for measuring the internal temperature of a lithium ion battery, a readable storage medium, an electronic device and an apparatus. BACKGROUND

[0002] The surface of a lithium ion battery is the only area where temperature can be measured, and the internal temperature of a lithium ion battery is currently estimated by combining surface temperature and an equivalent thermal model. Electrochemical impedance spectroscopy data of a lithium ion battery can reflect the core electrochemical process inside the battery, which changes in real time with the internal state of the electrode (temperature, state of charge SOC, service life SOH, etc.), and has good immediacy. The internal characteristic quantity of the battery can be obtained in a very short time, so electrochemical impedance spectroscopy data is very suitable for real-time monitoring of lithium ion batteries. The temperature of a lithium ion battery often rises from the inside, and surface temperature measurement is easily disturbed by the ambient temperature. This semi-empirical thermal equivalent model has limited estimation accuracy and is complex to calculate, and cannot respond in a timely manner to rapid changes in temperature, which increases the risk of using a lithium ion battery.

[0003] Therefore, how to measure the internal temperature of a lithium ion battery through electrochemical impedance spectroscopy data is a technical problem that needs to be solved at present. SUMMARY

[0004] In view of the above-mentioned shortcomings of the prior art, the present application provides a technical solution for measuring the internal temperature of a lithium ion battery based on electrochemical impedance spectroscopy data. The present application sets an internal reference temperature for a lithium ion battery, obtains first electrochemical impedance spectroscopy data at the internal reference temperature and second electrochemical impedance spectroscopy data at an unknown internal temperature, performs subtraction operation on the electrochemical impedance spectroscopy data at the two temperatures to obtain a difference function, finds the abscissa of the extreme point of the difference function, and substitutes the abscissa into the Arrhenius formula to calculate the unknown internal temperature of the lithium ion battery, thereby obtaining high-precision internal temperature data of the lithium ion battery.

[0005] To achieve the above and other related purposes, the technical solution provided by the present application is as follows.

[0006] A method for measuring the internal temperature of a lithium ion battery, comprising:

[0007] Setting an internal reference temperature of a lithium ion battery and obtaining first electrochemical impedance spectrum data of the lithium ion battery at the internal reference temperature; obtaining second electrochemical impedance spectrum data of the lithium ion battery at an internal unknown temperature; performing subtraction operation on the second electrochemical impedance spectrum data and the first electrochemical impedance spectrum data to obtain an electrochemical impedance spectrum data difference function; calculating an extreme point of the electrochemical impedance spectrum data difference function to obtain an abscissa of the extreme point, and substituting the abscissa of the extreme point into an Arrhenius formula to calculate the internal unknown temperature.

[0008] In the technical scheme provided in the embodiments of the present application, before the electrochemical impedance spectrum data of the lithium ion battery at the internal unknown temperature is obtained, under the excitation of a medium-high frequency signal, the internal equivalent circuit partition method of the lithium ion battery comprises: dividing the internal equivalent circuit of the lithium ion battery into a parasitic impedance module and a charge transfer module, wherein the parasitic impedance module is not affected by temperature, and the charge transfer module changes with temperature.

[0009] In the technical scheme provided in the embodiments of the present application, the step of setting the internal reference temperature of the lithium ion battery and obtaining the first electrochemical impedance spectrum data of the lithium ion battery at the internal reference temperature comprises: when the lithium ion battery is not working, measuring the temperature of the lithium ion battery by a built-in sensor and setting the temperature as the internal reference temperature; and measuring the first electrochemical impedance spectrum data at the internal reference temperature by the internal equivalent circuit method of the lithium ion battery.

[0010] In the technical scheme provided in the embodiments of the present application, the step of obtaining the second electrochemical impedance spectrum data of the lithium ion battery at the internal unknown temperature comprises: calculating a parasitic inductance value of the lithium ion battery at the internal unknown temperature; and obtaining the second electrochemical impedance spectrum data according to the parasitic inductance value.

[0011] In the technical scheme provided in the embodiments of the present application, the step of performing subtraction operation on the second electrochemical impedance spectrum data and the first electrochemical impedance spectrum data to obtain an electrochemical impedance spectrum data difference function comprises: obtaining the first electrochemical impedance spectrum data and the second electrochemical impedance spectrum data; performing subtraction operation on the second electrochemical impedance spectrum data and the first electrochemical impedance spectrum data to eliminate a parasitic impedance factor, and obtaining the electrochemical impedance spectrum data difference function according to the circuit relationship of the charge transfer module.

[0012] In the technical scheme provided by the embodiment of the present application, the extreme point operation on the electrochemical impedance spectrum data difference function is performed to obtain the abscissa of the extreme point, including: the electrochemical impedance spectrum data difference function is differentiated to obtain an electrochemical impedance spectrum data difference derivative function; when the numerator of the electrochemical impedance spectrum data difference derivative function is zero, the extreme point of the electrochemical impedance spectrum data difference function is obtained, and the abscissa of the extreme point is calculated.

[0013] In the technical scheme provided by the embodiment of the present application, the step of substituting the abscissa of the extreme point into the Arrhenius formula to calculate the internal unknown temperature includes: when the abscissa of the electrochemical impedance spectrum data difference function is the abscissa of the extreme point, the electrochemical impedance spectrum data difference function is only related to the charge transfer resistance, the charge transfer resistance is related to the electrochemical reaction activity, and the Arrhenius law is followed; the internal unknown temperature is calculated according to the fact that the electrochemical impedance spectrum data difference function at the extreme point abscissa satisfies the Arrhenius formula.

[0014] According to an aspect of an embodiment of the present application, a computer readable storage medium having computer readable instructions stored thereon is provided, when the computer readable instructions are executed by a processor of a computer, the computer is caused to perform the method for measuring the internal temperature of a lithium ion battery as described above.

[0015] According to an aspect of an embodiment of the present application, an electronic device is provided, including: one or more processors; a storage device for storing one or more programs, when the one or more programs are executed by the one or more processors, the electronic device is caused to implement the method for measuring the internal temperature of a lithium ion battery as described above.

[0016] According to an aspect of an embodiment of the present application, a device for measuring the internal temperature of a lithium ion battery is provided, the device includes: a measurement electrochemical impedance spectrum data module for measuring first electrochemical impedance spectrum data of the lithium ion battery at an internal reference temperature and second electrochemical impedance spectrum data at an internal unknown temperature; a data processing module for calculating the difference between the second electrochemical impedance spectrum data and the first electrochemical impedance spectrum data to obtain an electrochemical impedance spectrum data difference function, and calculating the abscissa of the extreme point of the electrochemical impedance spectrum data difference function; and a temperature conversion calculation module, if the electrochemical impedance spectrum data difference function at the extreme point abscissa, the Arrhenius formula is satisfied, and the internal unknown temperature of the lithium ion battery is calculated.

[0017] In the technical solutions provided in some embodiments of the present application, an internal reference temperature of a lithium-ion battery is set and first electrochemical impedance spectroscopy data at the internal reference temperature is obtained. Second electrochemical impedance spectroscopy data corresponding to an unknown internal temperature is obtained. A difference operation is performed on the two electrochemical impedance spectroscopy data to obtain an electrochemical impedance spectroscopy data difference function. The abscissa of the extreme point of the difference function is calculated, and the abscissa of the extreme point is substituted into the Arrhenius equation to calculate the unknown internal temperature of the lithium-ion battery. The present invention calculates the unknown internal temperature of the lithium-ion battery by setting the internal reference temperature and electrochemical impedance spectroscopy data, more comprehensively reflecting the internal chemical reactions of the lithium-ion battery, providing accurate lithium-ion battery reference data when managing and monitoring the status of the lithium-ion battery, and enabling timely repair and maintenance of the lithium-ion battery.

[0018] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a flow chart of a method for measuring an unknown internal temperature of a lithium-ion battery in one embodiment of the present invention;

[0020] Figure 2 is an equivalent circuit diagram of a lithium-ion battery in a medium and high frequency region according to an embodiment of the present invention;

[0021] Figure 3 is a charge transfer impedance circuit diagram of a lithium-ion battery in one embodiment of the present invention;

[0022] Figure 4 18650 battery in one embodiment of the present invention at different temperatures.

[0023] Figure 5 yes Figure 4 The relationship between the horizontal coordinate of the extreme point and temperature. DETAILED DESCRIPTION

[0024] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other unless they conflict.

[0025] It is to be noted that the drawings provided in the following embodiments only schematically illustrate the basic concepts of the present application, and only the components related to the present application are shown in the drawings, rather than being drawn according to the number, shape and size of the components in actual implementation. The actual implementation of each component may be a random change, and the component layout may be more complex.

[0026] In the following description, a large number of details are discussed to provide a more thorough explanation of the embodiments of the present application. However, it is obvious to those skilled in the art that the embodiments of the present application can be implemented without these specific details, and in other embodiments, the known structures and devices are shown in the form of block diagrams rather than in the form of details, so as not to make the embodiments of the present application difficult to understand.

[0027] The inventors have found that the current measurement of the temperature of the lithium ion battery is generally to measure the surface temperature of the lithium ion battery, and the internal temperature of the lithium ion battery is mainly estimated by combining the surface temperature and the equivalent model. This makes the internal temperature of the lithium ion battery not accurate, which has great disadvantages for managing and monitoring the lithium ion battery. When the internal chemical change of the lithium ion battery is abnormal, the change of the internal temperature cannot be accurately monitored, which changes the service life of the lithium ion battery and increases the risk.

[0028] To solve the above technical problems, the present application provides a technical solution for measuring the internal temperature of a lithium ion battery: setting an internal reference temperature, obtaining electrochemical impedance spectrum data at the internal reference temperature and at an unknown internal temperature, performing subtraction operation on the electrochemical impedance spectrum data at the two different temperatures to obtain an electrochemical impedance spectrum data difference function, calculating the abscissa of the extreme point of the electrochemical impedance spectrum data difference function, and substituting the abscissa into the Arrhenius formula to calculate the unknown internal temperature of the lithium ion battery.

[0029] The following is a detailed description of the implementation details of the technical solutions of the embodiments of the present application:

[0030] Figure 1 The following is a flowchart of a method for measuring the internal temperature of a lithium ion battery according to an exemplary embodiment of the present application, which comprises at least steps S110 to S140, and the details are as follows:

[0031] In step S110, the internal reference temperature of the lithium ion battery is set and the first electrochemical impedance spectrum data of the lithium ion battery at the internal reference temperature is obtained.

[0032] In an embodiment of the present application, before obtaining the electrochemical impedance spectrum data of the lithium ion battery at the unknown internal temperature, the lithium ion battery internal equivalent circuit partitioning method is divided under the excitation of a medium-high frequency signal, such asFigure 2 As shown: the internal equivalent circuit of lithium ion battery is divided into parasitic impedance module and charge transfer module, the circuit impedance in the dotted box ① is the parasitic impedance module, wherein R0 is the series resistance component in the measurement circuit, L1, L2, R L The impedance value in ① is not affected by temperature, and the impedance value of the parasitic impedance module is shown as expression (1):

[0033] Z para (ω)=A para (ω)+j·B para (ω) (1)

[0034] Wherein, Z para (ω) is the impedance of the parasitic impedance module, A para (ω) is the real part of the impedance of the parasitic impedance module, and B para (ω) is the imaginary part of the impedance of the parasitic impedance module.

[0035] The circuit impedance in the dotted box ② is the charge transfer module, C ct is the double-layer capacitance, and R ct is the charge transfer resistance. Wherein, C ct changes little with temperature, and R ct is related to the activation energy of the reaction and changes obviously with temperature. The impedance value of the charge transfer module is shown as expression (2):

[0036] Z ct (ω)=A ct (ω)+j·B ct (ω) (2)

[0037] Wherein, Z ct (ω) is the impedance of the charge transfer module, A ct (ω) is the real part of the impedance of the charge transfer module, and B ct (ω) is the imaginary part of the impedance of the charge transfer module.

[0038] The actual measured circuit impedance value is the sum of the impedance of the parasitic impedance module and the impedance of the charge transfer module, as shown in expression (3):

[0039] Z(ω)=Z para (ω)+Z CT (ω)=A para (ω)+j·B para (ω)+A ct (ω)+j·B ct (ω) (3)

[0040] In an embodiment of the present application, the step of setting the internal reference temperature of the lithium ion battery and obtaining the first electrochemical impedance spectrum data of the lithium ion battery at the internal reference temperature: when the lithium ion battery is not working, the temperature of the lithium ion battery is measured by the built-in sensor and the temperature is set as the internal reference temperature; the first electrochemical impedance spectrum data at the internal reference temperature is measured by the internal equivalent circuit method of the lithium ion battery, and the first electrochemical impedance spectrum data is shown in expression (4):

[0041] Z T0 =A para (ω)+j·B para (ω)+A ct0 (ω)+j·B ct0 (ω) (4)

[0042] Wherein, Z T0 is the impedance value at the internal reference temperature, A para (ω) is the impedance real part of the parasitic impedance module, B para (ω) is the impedance imaginary part of the parasitic impedance module, A ct0 (ω) is the impedance real part of the charge transfer module at the internal reference temperature, B ct0 (ω) is the impedance imaginary part of the charge transfer module at the internal reference temperature.

[0043] In step S120, the second electrochemical impedance spectrum data of the lithium ion battery at the internal unknown temperature is obtained.

[0044] In an embodiment of the present application, the step of obtaining the second electrochemical impedance spectrum data of the lithium ion battery at the internal unknown temperature, comprising: calculating the parasitic inductance value of the lithium ion battery at the internal unknown temperature; obtaining the second electrochemical impedance spectrum data according to the parasitic inductance value, and the second electrochemical impedance spectrum data is shown in expression (5):

[0045] Z Tn =A para (ω)+j·B para (ω)+A ctn (ω)+j·B ctn (ω) (5)

[0046] Wherein, Z Tn is the impedance value at the internal unknown temperature, A para (ω) is the impedance real part of the parasitic impedance module, B para (ω) is the impedance imaginary part of the parasitic impedance module, A ctn (ω) is the impedance real part of the charge transfer module at the internal unknown temperature, B ctn (ω) is the impedance imaginary part of the charge transfer module at the internal unknown temperature.

[0047] In step S130 , a subtraction operation is performed on the second electrochemical impedance spectroscopy data and the first electrochemical impedance spectroscopy data to obtain an electrochemical impedance spectroscopy data difference function.

[0048] In one embodiment of the present application, subtracting the second electrochemical impedance spectroscopy data from the first electrochemical impedance spectroscopy data to obtain an electrochemical impedance spectroscopy data difference function includes: acquiring the first electrochemical impedance spectroscopy data and the second electrochemical impedance spectroscopy data; and subtracting the second electrochemical impedance spectroscopy data from the first electrochemical impedance spectroscopy data, as shown in Expression (6):

[0049] ΔZ Tn =Z Tn -Z T0 =A ctn (ω)+j·B ctn (ω)-A ct0 (ω)-j·B ct0 (ω) (6)

[0050] Where ΔZ Tn is the electrochemical impedance spectroscopy data difference function, A ctn (ω) is the real part of the impedance of the charge transfer module at the internal unknown temperature, B ctn (ω) is the imaginary impedance part of the charge transfer module at the internal unknown temperature, A ct0 (ω) is the real part of the impedance of the charge transfer module at the internal reference temperature, B ct0 (ω) is the imaginary impedance of the charge transfer module at the internal reference temperature.

[0051] Impedance difference can eliminate the parasitic impedance factor, to determine the impedance difference ΔZ Tn The relationship with temperature, such as Figure 3 The circuit impedance shown is as shown in expression (7):

[0052]

[0053] Among them, Z ct (ω) is the impedance value, A ct (ω) is the real part of impedance, B ct (ω) is the imaginary part of impedance, C ct is the double layer capacitance, R ct is the charge transfer resistance.

[0054] The electrochemical impedance spectroscopy data difference function can be obtained from expression (7), as shown in expression (8):

[0055]

[0056] Where ΔZ Tn(ω) is the electrochemical impedance spectroscopy data difference function, C ctn is the double layer capacitance at an internal unknown temperature, R ctn is the charge transfer resistance at an internal unknown temperature, C ct0 is the double layer capacitance at an internal reference temperature, R ct0 is the charge transfer resistance at an internal reference temperature.

[0057] Because C ct belongs to the double layer capacitance, which does not change much with temperature, so here we set C ct0 = C ctn = C.

[0058] In step S140, the extreme point of the electrochemical impedance spectroscopy data difference function is calculated, the abscissa of the extreme point is obtained, and the abscissa of the extreme point is substituted into the Arrhenius formula to calculate the internal unknown temperature.

[0059] In an embodiment of the present application, the extreme point operation is performed on the electrochemical impedance spectroscopy data difference function, the abscissa of the extreme point is obtained, and ΔZ Tn The real part difference of the electrochemical impedance spectroscopy data difference function (ω) is the abscissa x, and the difference of the opposite number of the imaginary part is the ordinate y, so that expressions (9) and (10) can be obtained;

[0060]

[0061]

[0062] Wherein, R ctn is the charge transfer resistance at an internal unknown temperature, C is the double layer capacitance, R ct0 is the charge transfer resistance at an internal reference temperature.

[0063] The derivatives of x and y are obtained respectively, and expressions (11) and (12) are obtained:

[0064]

[0065]

[0066] Therefore:

[0067]

[0068] The extreme point is obtained, and The molecule is zero, as shown in expression (14):

[0069] (CR ct0 2 -ω 2 C 3 R ct04 )·(1+ω 2 C 2 R ctn 2 ) 2 -(CR ctn 2 -ω 2 C 3 R ctn 4 )(1+ω 2 C 2 R ct0 2 ) 2 =0(14)

[0070] Simplifying expression (14) yields expression (15),

[0071] 3ω 4 C 4 R ct0 2 R ctn 2 +ω 2 C 2 (R ct0 2 +R ctn 2 )-1=0 (15)

[0072] The horizontal coordinate of the extreme point is:

[0073]

[0074] So ΔZ Tn The imaginary part y of (ω) takes its extreme value when ω=ω0, and at this time ΔZ Tn The real part x of (ω) is shown in expression (17):

[0075]

[0076] From expression (17), we can see that the value at ω = ω0 is only related to the charge transfer resistance. The charge transfer resistance is related to the electrochemical reaction activity and follows the Arrhenius law. It can be deduced that when ω = ω0, ΔZ Tn The real part x of (ω) also follows the Arrhenius law, that is, ΔZ Tn (ω) The horizontal coordinate value of the function at the extreme point follows the Arrhenius law.

[0077] The Arrhenius formula is shown in expression (18):

[0078]

[0079] wherein k is a rate constant, R is a molar gas constant, T is a thermodynamic temperature, Ea is an apparent activation energy, and A is a frequency factor.

[0080] In the lithium ion battery, the parameters in the Arrhenius formula except the thermodynamic temperature are considered as constants, and the ΔZ measured at the internal unknown temperature of the lithium ion battery is Tn The expression of x(ω) is (19) when the abscissa of the extreme point is

[0081]

[0082] The internal unknown temperature of the lithium ion battery can be calculated according to the expression (19).

[0083] The measurement of the internal temperature of the lithium ion battery by the electrochemical impedance spectrum data, Figure 4 The x-y relationship curve of the differential processed electrochemical impedance spectrum data of the 18650 battery at 0-70℃, Figure 4 The relationship between the abscissa of the extreme point and the temperature is shown in Figure 5 It can be seen that the experimental test data are consistent with the theoretical model. Figure 5

[0084] Another aspect of the present application also provides a computer readable storage medium having a computer program stored thereon, which, when executed by a processor of a computer, causes the computer to execute the method for measuring the internal temperature of the lithium ion battery as described above. The computer readable storage medium can be included in the electronic device described in the above embodiments, or can exist separately without being assembled into the electronic device.

[0085] Embodiments of the present application also provide an electronic device, comprising: one or more processors; a storage device for storing one or more programs, which, when executed by the one or more processors, cause the electronic device to implement the method for measuring the internal temperature of the lithium ion battery provided in the above embodiments.

[0086] Another aspect of the present application also provides a device for measuring the internal temperature of the lithium ion battery, comprising: a module for measuring electrochemical impedance spectrum data, for measuring first electrochemical impedance spectrum data of the lithium ion battery at an internal reference temperature and second electrochemical impedance spectrum data at an internal unknown temperature; a data processing module, for calculating the difference between the second electrochemical impedance spectrum data and the first electrochemical impedance spectrum data to obtain an electrochemical impedance spectrum data difference function, and calculating the abscissa of the extreme point of the electrochemical impedance spectrum data difference function; a temperature conversion calculation module, if the electrochemical impedance spectrum data difference function is at the abscissa of the extreme point, the Arrhenius formula is satisfied, and the internal unknown temperature of the lithium ion battery is calculated.​

[0087] The application provides a technical solution for measuring the internal temperature of a lithium ion battery, which sets an internal reference temperature of the lithium ion battery, respectively acquires first electrochemical impedance spectrum data under the internal reference temperature and second electrochemical impedance spectrum data under an unknown internal temperature, performs subtraction operation on the electrochemical impedance spectrum data under the two temperatures to obtain an electrochemical impedance spectrum data difference function, calculates an extreme point abscissa of the electrochemical impedance spectrum data difference function, substitutes the abscissa into an Arrhenius formula, and obtains the unknown internal temperature of the lithium ion battery. When the lithium ion battery is abnormal, the solution acquires the internal temperature of the lithium ion battery in real time, judges the abnormal condition of the lithium ion battery through the internal temperature of the lithium ion battery and other electrochemical reactions, and makes a relevant response in time, thereby appropriately prolonging the service life and protecting the battery.

[0088] It should be understood that the above-mentioned content is only the preferred exemplary embodiments of the application, not for limiting the implementation of the application, and the person skilled in the art can easily make corresponding variations or modifications according to the main concept and spirit of the application, so the protection scope of the application should be subject to the protection scope required by the claims.

Claims

1. A method for measuring the internal temperature of a lithium-ion battery, characterized in that: include: Setting an internal reference temperature of a lithium-ion battery and obtaining first electrochemical impedance spectroscopy data of the lithium-ion battery at the internal reference temperature; Acquiring second electrochemical impedance spectroscopy data of the lithium-ion battery at an unknown internal temperature; performing a subtraction operation on the second electrochemical impedance spectroscopy data from the first electrochemical impedance spectroscopy data to obtain an electrochemical impedance spectroscopy data difference function; Calculating the extreme point of the electrochemical impedance spectroscopy data difference function to obtain the abscissa of the extreme point, and substituting the abscissa of the extreme point into the Arrhenius formula to calculate the internal unknown temperature; Before obtaining electrochemical impedance spectroscopy data of the lithium-ion battery at an unknown internal temperature, the internal equivalent circuit segmentation method of the lithium-ion battery under the excitation of a medium-high frequency signal includes: The internal equivalent circuit of the lithium-ion battery is divided into a parasitic impedance module and a charge transfer module, wherein the parasitic impedance module is not affected by temperature, and the charge transfer module changes with temperature.

2. The method for measuring the internal temperature of a lithium-ion battery according to claim 1, wherein: The step of setting the internal reference temperature of the lithium-ion battery and obtaining first electrochemical impedance spectroscopy data of the lithium-ion battery at the internal reference temperature includes: When the lithium-ion battery is not working, measuring the temperature of the lithium-ion battery by a built-in sensor and setting the temperature as an internal reference temperature; The first electrochemical impedance spectroscopy data at an internal reference temperature is measured using a lithium-ion battery internal equivalent circuit method.

3. The method for measuring the internal temperature of a lithium-ion battery according to claim 1, wherein: The step of obtaining second electrochemical impedance spectroscopy data of the lithium-ion battery at an unknown internal temperature includes: Calculating the parasitic inductance of the lithium-ion battery at an unknown internal temperature; The second electrochemical impedance spectroscopy data is obtained according to the parasitic inductance value.

4. The method for measuring the internal temperature of a lithium-ion battery according to claim 1, wherein: Subtracting the second electrochemical impedance spectroscopy data from the first electrochemical impedance spectroscopy data to obtain an electrochemical impedance spectroscopy data difference function includes: Acquiring the first electrochemical impedance spectroscopy data and the second electrochemical impedance spectroscopy data; The second electrochemical impedance spectroscopy data is subtracted from the first electrochemical impedance spectroscopy data to eliminate the parasitic impedance factor, and the electrochemical impedance spectroscopy data difference function is obtained according to the circuit relationship of the charge transfer module.

5. The method for measuring the internal temperature of a lithium-ion battery according to claim 1, wherein: Performing an extreme point operation on the electrochemical impedance spectroscopy data difference function to obtain the abscissa of the extreme point includes: Derivative the electrochemical impedance spectroscopy data difference function to obtain an electrochemical impedance spectroscopy data difference derivative function; When the numerator of the electrochemical impedance spectroscopy data difference derivative function is zero, it is an extreme point of the electrochemical impedance spectroscopy data difference function, and the abscissa of the extreme point is calculated.

6. The method for measuring the internal temperature of a lithium-ion battery according to claim 1, wherein: The step of substituting the abscissa of the extreme point into the Arrhenius formula to calculate the unknown internal temperature includes: When the abscissa of the electrochemical impedance spectroscopy data difference function is the abscissa of the extreme point, the electrochemical impedance spectroscopy data difference function is only related to the charge transfer resistance, and the charge transfer resistance is related to the electrochemical reaction activity and follows the Arrhenius law; The internal unknown temperature is calculated based on the electrochemical impedance spectroscopy data difference function at the extreme point abscissa satisfying the Arrhenius formula.

7. A computer-readable storage medium, characterized in that Computer-readable instructions are stored thereon, and when the computer-readable instructions are executed by a processor of a computer, the computer is caused to execute the method for measuring the internal temperature of a lithium-ion battery according to any one of claims 1 to 6.

8. An electronic device, characterized in that: include: one or more processors; A storage device for storing one or more programs, which, when executed by the one or more processors, enables the electronic device to implement the method for measuring the internal temperature of a lithium-ion battery as described in any one of claims 1 to 6.

9. A device for measuring the internal temperature of a lithium-ion battery, characterized in that: include: An electrochemical impedance spectroscopy data measuring module is used to measure first electrochemical impedance spectroscopy data at an internal reference temperature of the lithium-ion battery and second electrochemical impedance spectroscopy data at an internal unknown temperature; a data processing module, configured to calculate a difference between the second electrochemical impedance spectroscopy data and the first electrochemical impedance spectroscopy data to obtain an electrochemical impedance spectroscopy data difference function, and perform abscissa calculation of an extreme point of the electrochemical impedance spectroscopy data difference function; The temperature conversion calculation module calculates the internal unknown temperature of the lithium-ion battery if the electrochemical impedance spectroscopy data difference function satisfies the Arrhenius formula when it is at the extreme point abscissa.

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