A method and device for estimating SOC of retired batteries based on electrochemical impedance spectroscopy

Abstract

The present invention relates to a method and device for estimating the SOC of retired batteries based on electrochemical impedance spectroscopy. The method comprises: obtaining electrochemical impedance spectra of several retired batteries at different SOC values, obtaining characteristic parameters based on the electrochemical impedance spectra, and screening the characteristic parameters to obtain screened characteristic parameters; constructing an estimation model, and training the estimation model based on the screened characteristic parameters to obtain a fully trained estimation model; obtaining real-time characteristic parameters of the retired battery to be estimated, and obtaining an estimated SOC value of the retired battery to be estimated based on the real-time characteristic parameters and the fully trained estimation model. The method for estimating the SOC of retired batteries based on electrochemical impedance spectroscopy disclosed by the present invention ensures the accuracy of the SOC estimation of retired batteries.

Description

Technical Field

[0001] The present invention relates to the technical field of retired batteries, and in particular to a retired battery SOC estimation method, device, electronic device, and computer-readable storage medium based on electrochemical impedance spectroscopy. Background Art

[0002] With the development of science and technology, lithium-ion batteries have gradually become an important energy storage and supply carrier in many industries due to their comprehensive advantages such as small size, high energy density, high operating voltage, and long life cycle. The estimation of lithium-ion battery SOC (State of Charge) is a cutting-edge technology for fault diagnosis and health management of retired lithium-ion batteries. It has been valued by more and more researchers and has gradually become a research hotspot in electronic system health management and fault diagnosis.

[0003] Common methods that have been applied to SOC estimation of retired lithium batteries include the Kalman filter recursive algorithm. The Kalman filter method regards the battery as a dynamic system and the SOC as a state quantity within the system. This method requires the selection of a descriptive equation for the dynamic system, and the recursive process also involves complex matrix inversion operations. At the same time, as a recursive algorithm, the Kalman filter is very sensitive to the selection of initial values. Incorrect initial values ​​lead to continuous deterioration of the estimate. Therefore, this method has limitations and cannot guarantee the accuracy of SOC estimation. Summary of the Invention

[0004] In view of this, it is necessary to provide a retired battery SOC estimation method, device, electronic device and computer-readable storage medium based on electrochemical impedance spectroscopy to solve the problem in the existing technology that the retired battery SOC cannot be accurately estimated.

[0005] In order to solve the above problems, the present invention provides a method for estimating the SOC of a retired battery based on electrochemical impedance spectroscopy, comprising:

[0006] Obtaining electrochemical impedance spectra of several retired batteries at different SOC values, obtaining characteristic parameters based on the electrochemical impedance spectra, and screening the characteristic parameters to obtain screened characteristic parameters;

[0007] Constructing an estimation model, and training the estimation model according to the filtered characteristic parameters to obtain a fully trained estimation model;

[0008] Real-time characteristic parameters of the retired battery to be estimated are obtained, and an estimated SOC value of the retired battery to be estimated is obtained according to the real-time characteristic parameters and the well-trained estimation model.

[0009] Furthermore, characteristic parameters are obtained according to the electrochemical impedance spectroscopy, including:

[0010] The electrochemical impedance spectroscopy is used to obtain the real part value, imaginary part value and open circuit voltage corresponding to the plurality of retired batteries at different frequencies as characteristic parameters.

[0011] Furthermore, screening the characteristic parameters includes:

[0012] The correlation coefficient calculation formula is used to calculate the correlation value between the characteristic parameter and the corresponding retired battery SOC value. If the absolute value of the correlation value is less than a set threshold, the characteristic parameter is eliminated.

[0013] Furthermore, the correlation coefficient calculation formula is:

[0014]

[0015] Among them, X is the characteristic parameter, Y is the corresponding retired battery SOC value, ρ X,Y is the correlation value.

[0016] Furthermore, an estimation model is constructed, including:

[0017] Construct a support vector machine regression prediction estimation model.

[0018] Furthermore, the estimation model is trained according to the filtered feature parameters, including:

[0019] The estimation model is trained by taking the filtered characteristic parameters as input values ​​and taking the corresponding retired battery SOC values ​​as output values.

[0020] Furthermore, obtaining an estimated SOC value of the retired battery to be estimated based on the real-time characteristic parameters and the well-trained estimation model includes:

[0021] An initial SOC estimation value is obtained by using the real-time characteristic parameters and the well-trained estimation model, and an inverse normalization process is performed on the initial SOC estimation value to obtain an SOC estimation value of the retired battery to be estimated.

[0022] The present invention also provides a retired battery SOC estimation device based on electrochemical impedance spectroscopy, comprising a parameter acquisition module, a model training module and an estimated value acquisition module;

[0023] The parameter acquisition module is used to obtain electrochemical impedance spectra of several retired batteries at different SOC values, obtain characteristic parameters based on the electrochemical impedance spectra, and screen the characteristic parameters to obtain screened characteristic parameters;

[0024] The model training module is used to construct an estimation model and train the estimation model according to the filtered feature parameters to obtain a fully trained estimation model;

[0025] The estimated value acquisition module is used to obtain real-time characteristic parameters of the retired battery to be estimated, and obtain the SOC estimated value of the retired battery to be estimated based on the real-time characteristic parameters and the trained estimation model.

[0026] The present invention also provides an electronic device comprising a memory and a processor, wherein a computer program is stored on the memory, and when the computer program is executed by the processor, the method for estimating the SOC of a retired battery based on electrochemical impedance spectroscopy as described in any of the above technical solutions is implemented.

[0027] The present invention also provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for estimating the SOC of a retired battery based on electrochemical impedance spectroscopy as described in any of the above technical solutions is implemented.

[0028] The beneficial effect of adopting the above embodiment is as follows: the retired battery SOC estimation method based on electrochemical impedance spectroscopy provided by the present invention obtains characteristic parameters by electrochemical impedance spectroscopy of several retired batteries at different SOC values, screens the characteristic parameters, and selects more suitable characteristic parameters, which can improve the accuracy of retired battery SOC estimation, and constructs an estimation model. The model is trained using the screened characteristic parameters to obtain a fully trained estimation model. The fully trained estimation model is used to estimate the SOC of retired batteries, thereby ensuring the accuracy of retired battery SOC estimation. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic flow chart of an embodiment of a method for estimating SOC of a retired battery based on electrochemical impedance spectroscopy provided by the present invention;

[0030] Figure 2 This is a structural block diagram of an embodiment of a retired battery SOC estimation device based on electrochemical impedance spectroscopy provided by the present invention;

[0031] Figure 3 This is a structural block diagram of an embodiment of an electronic device provided by the present invention. DETAILED DESCRIPTION

[0032] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, and are not used to limit the scope of the present invention.

[0033] The present invention provides a method, device, electronic device and computer-readable storage medium for estimating the SOC of a retired battery based on electrochemical impedance spectroscopy, which are described in detail below.

[0034] The embodiment of the present invention provides a method for estimating the SOC of a retired battery based on electrochemical impedance spectroscopy, the flow chart of which is as follows: Figure 1 As shown, the retired battery SOC estimation method based on electrochemical impedance spectroscopy includes:

[0035] Step S101: Obtain electrochemical impedance spectra of several retired batteries at different SOC values, obtain characteristic parameters based on the electrochemical impedance spectra, and screen the characteristic parameters to obtain screened characteristic parameters;

[0036] Step S102: constructing an estimation model, and training the estimation model according to the filtered feature parameters to obtain a fully trained estimation model;

[0037] Step S103: acquiring real-time characteristic parameters of the retired battery to be estimated, and obtaining an estimated SOC value of the retired battery to be estimated based on the real-time characteristic parameters and the well-trained estimation model.

[0038] In a specific embodiment, electrochemical impedance spectra of several retired batteries at different SOC values ​​are obtained. The step of obtaining characteristic parameters based on the electrochemical impedance spectra includes adjusting the retired batteries to different SOCs (ΔSOC=5%) at 0.05C to 1C, standing for a sufficiently long time to obtain the battery open circuit voltage U, and performing an AC impedance test on the battery using an impedance spectrum tester at a temperature of (25±2)°C and a frequency of 0.05 to 100 kHz at different frequency points to obtain the electrochemical impedance spectrum.

[0039] As a preferred embodiment, characteristic parameters are obtained according to the electrochemical impedance spectroscopy, including:

[0040] The electrochemical impedance spectroscopy is used to obtain the real part value, imaginary part value and open circuit voltage corresponding to the plurality of retired batteries at different frequencies as characteristic parameters.

[0041] As a preferred embodiment, screening the characteristic parameters includes:

[0042] The correlation coefficient calculation formula is used to calculate the correlation value between the characteristic parameter and the corresponding retired battery SOC value. If the absolute value of the correlation value is less than a set threshold, the characteristic parameter is eliminated.

[0043] It should be noted that the threshold is set according to specific circumstances and is generally set to 95%.

[0044] As a preferred embodiment, the correlation coefficient calculation formula is:

[0045]

[0046] Among them, X is the characteristic parameter, Y is the corresponding retired battery SOC value, ρ X,Y is the correlation value.

[0047] As a preferred embodiment, constructing an estimation model includes:

[0048] Construct a support vector machine regression prediction estimation model.

[0049] In a specific embodiment, an SVM regression prediction estimation model is created, and the loss function metric of the SVM is as follows:

[0050]

[0051] Among them, ε is a constant, ω is a weight, b is a bias, φ(x i ) is the mapping from the input space to a feature space. For a sample point (x i ,y i ), if |y i -ω·φ(x i )-b|≤ε, then there is no loss at all, if |y i -ω·φ(x i )-b|>ε, then the corresponding loss is |y i -ω·φ(x i )-b|-ε.

[0052] As a preferred embodiment, training the estimation model according to the filtered feature parameters includes:

[0053] The estimation model is trained by taking the filtered characteristic parameters as input values ​​and taking the corresponding retired battery SOC values ​​as output values.

[0054] As a preferred embodiment, obtaining the estimated SOC value of the retired battery to be estimated based on the real-time characteristic parameters and the well-trained estimation model includes:

[0055] An initial SOC estimation value is obtained by using the real-time characteristic parameters and the well-trained estimation model, and an inverse normalization process is performed on the initial SOC estimation value to obtain an SOC estimation value of the retired battery to be estimated.

[0056] It should be noted that using a well-trained estimation model to estimate the SOC of retired batteries can ensure the accuracy of the SOC estimation of retired batteries.

[0057] The embodiment of the present invention also provides a retired battery SOC estimation device based on electrochemical impedance spectroscopy, the structural block diagram of which is as follows: Figure 2As shown, the retired battery SOC estimation device based on electrochemical impedance spectroscopy includes a parameter acquisition module 201, a model training module 202 and an estimated value acquisition module 203;

[0058] The parameter acquisition module 201 is used to obtain electrochemical impedance spectra of several retired batteries at different SOC values, obtain characteristic parameters based on the electrochemical impedance spectra, and screen the characteristic parameters to obtain screened characteristic parameters;

[0059] The model training module 202 is used to construct an estimation model and train the estimation model according to the filtered feature parameters to obtain a fully trained estimation model;

[0060] The estimated value acquisition module 203 is used to acquire real-time characteristic parameters of the retired battery to be estimated, and obtain an SOC estimated value of the retired battery to be estimated based on the real-time characteristic parameters and the trained estimation model.

[0061] like Figure 3 As shown, the present invention also provides an electronic device for estimating the SOC of retired batteries based on electrochemical impedance spectroscopy. The electronic device can be a computing device such as a mobile terminal, desktop computer, notebook, PDA, or server. The electronic device includes a processor 303, a display 302, and a memory 301.

[0062] In some embodiments, the memory 301 may be an internal storage unit of a computer device, such as a hard drive or memory of the computer device. In other embodiments, the memory 301 may also be an external storage device of the computer device, such as a plug-in hard drive, a Smart Media Card (SMC), a Secure Digital (SD) card, a flash card, etc. equipped on the computer device. Furthermore, the memory 301 may include both an internal storage unit of the computer device and an external storage device. The memory 301 is used to store application software installed on the computer device and various types of data, such as program code installed on the computer device. The memory 301 may also be used to temporarily store data that has been output or is about to be output. In one embodiment, the memory 301 stores a retired battery SOC estimation program 304 based on electrochemical impedance spectroscopy. The retired battery SOC estimation program 304 based on electrochemical impedance spectroscopy can be executed by the processor 303, thereby implementing the retired battery SOC estimation method based on electrochemical impedance spectroscopy according to various embodiments of the present invention.

[0063] In some embodiments, the processor 303 may be a central processing unit (CPU), a microprocessor, or other data processing chip, configured to execute program codes or process data stored in the memory 301 , such as executing a retired battery SOC estimation program based on electrochemical impedance spectroscopy.

[0064] In some embodiments, display 302 can be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, or an OLED (Organic Light-Emitting Diode) touchscreen. Display 302 is used to display information on the computer device and to display a visual user interface. Components 301-303 of the computer device communicate with each other via a system bus.

[0065] In one embodiment, when the processor 303 executes the retired battery SOC estimation program 304 based on electrochemical impedance spectroscopy in the memory 301 , the following steps are implemented:

[0066] Obtaining electrochemical impedance spectra of several retired batteries at different SOC values, obtaining characteristic parameters based on the electrochemical impedance spectra, and screening the characteristic parameters to obtain screened characteristic parameters;

[0067] Constructing an estimation model, and training the estimation model according to the filtered characteristic parameters to obtain a fully trained estimation model;

[0068] Real-time characteristic parameters of the retired battery to be estimated are obtained, and an estimated SOC value of the retired battery to be estimated is obtained according to the real-time characteristic parameters and the well-trained estimation model.

[0069] This embodiment further provides a computer-readable storage medium storing a retired battery SOC estimation program based on electrochemical impedance spectroscopy. When the retired battery SOC estimation program based on electrochemical impedance spectroscopy is executed by a processor, the following steps are implemented:

[0070] Obtaining electrochemical impedance spectra of several retired batteries at different SOC values, obtaining characteristic parameters based on the electrochemical impedance spectra, and screening the characteristic parameters to obtain screened characteristic parameters;

[0071] Constructing an estimation model, and training the estimation model according to the filtered characteristic parameters to obtain a fully trained estimation model;

[0072] Real-time characteristic parameters of the retired battery to be estimated are obtained, and an estimated SOC value of the retired battery to be estimated is obtained according to the real-time characteristic parameters and the well-trained estimation model.

[0073] The present invention provides a method, device, electronic device, and computer-readable storage medium for estimating the SOC of retired batteries based on electrochemical impedance spectroscopy. Characteristic parameters are obtained by electrochemical impedance spectroscopy of several retired batteries at different SOC values, and the characteristic parameters are screened to select more suitable characteristic parameters, thereby improving the accuracy of SOC estimation of retired batteries. An estimation model is constructed and the model is trained using the screened characteristic parameters to obtain a fully trained estimation model. The fully trained estimation model is used to estimate the SOC of retired batteries, thereby ensuring the accuracy of SOC estimation of retired batteries.

[0074] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Any reference to memory, storage, database or other media used in the embodiments provided in this application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0075] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for estimating SOC of retired batteries based on electrochemical impedance spectroscopy, characterized in that: include: Obtaining electrochemical impedance spectra of several retired batteries at different SOC values, obtaining characteristic parameters based on the electrochemical impedance spectra, and screening the characteristic parameters to obtain screened characteristic parameters; Constructing an estimation model, and training the estimation model according to the filtered characteristic parameters to obtain a fully trained estimation model; Acquiring real-time characteristic parameters of the retired battery to be estimated, and obtaining an estimated SOC value of the retired battery to be estimated based on the real-time characteristic parameters and the well-trained estimation model; Screening the characteristic parameters includes: The correlation coefficient calculation formula is used to calculate the correlation value between the characteristic parameter and the corresponding retired battery SOC value. If the absolute value of the correlation value is less than a set threshold, the characteristic parameter is eliminated.

2. The method for estimating SOC of retired batteries based on electrochemical impedance spectroscopy according to claim 1, characterized in that: Characteristic parameters are obtained according to the electrochemical impedance spectroscopy, including: The electrochemical impedance spectroscopy is used to obtain the real part value, imaginary part value and open circuit voltage corresponding to the plurality of retired batteries at different frequencies as characteristic parameters.

3. The method for estimating SOC of retired batteries based on electrochemical impedance spectroscopy according to claim 1, characterized in that: The correlation coefficient calculation formula is: ， Among them, X is the characteristic parameter, Y is the corresponding retired battery SOC value, is the correlation value.

4. The method for estimating SOC of retired batteries based on electrochemical impedance spectroscopy according to claim 1, characterized in that: Construct an estimation model, including: Construct a support vector machine regression prediction estimation model.

5. The method for estimating SOC of retired batteries based on electrochemical impedance spectroscopy according to claim 1, characterized in that: Training the estimation model according to the filtered feature parameters includes: The estimation model is trained by taking the filtered characteristic parameters as input values ​​and taking the corresponding retired battery SOC values ​​as output values.

6. The method for estimating SOC of retired batteries based on electrochemical impedance spectroscopy according to claim 1, characterized in that: Obtaining an estimated SOC value of the retired battery to be estimated according to the real-time characteristic parameters and the well-trained estimation model, including: An initial SOC estimation value is obtained by using the real-time characteristic parameters and the well-trained estimation model, and an inverse normalization process is performed on the initial SOC estimation value to obtain an SOC estimation value of the retired battery to be estimated.

7. A retired battery SOC estimation device based on electrochemical impedance spectroscopy, characterized in that: Including parameter acquisition module, model training module and estimation value acquisition module; The parameter acquisition module is used to obtain electrochemical impedance spectra of several retired batteries at different SOC values, obtain characteristic parameters based on the electrochemical impedance spectra, and screen the characteristic parameters to obtain screened characteristic parameters; The model training module is used to construct an estimation model and train the estimation model according to the filtered feature parameters to obtain a fully trained estimation model; The estimated value acquisition module is used to obtain real-time characteristic parameters of the retired battery to be estimated, and obtain an SOC estimation value of the retired battery to be estimated based on the real-time characteristic parameters and the trained estimation model; Screening the characteristic parameters includes: The correlation coefficient calculation formula is used to calculate the correlation value between the characteristic parameter and the corresponding retired battery SOC value. If the absolute value of the correlation value is less than a set threshold, the characteristic parameter is eliminated.

8. An electronic device, characterized in that: The method comprises a memory and a processor, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the method for estimating the SOC of a retired battery based on electrochemical impedance spectroscopy according to any one of claims 1 to 6 is implemented.

9. A computer-readable storage medium, characterized in that A computer program is stored thereon, and when the computer program is executed by a processor, the method for estimating the SOC of a retired battery based on electrochemical impedance spectroscopy as claimed in any one of claims 1 to 6 is implemented.

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