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CN-121995253-A - Method and device for determining charge state of battery cell, storage medium and electronic equipment

CN121995253ACN 121995253 ACN121995253 ACN 121995253ACN-121995253-A

Abstract

The application belongs to the technical field of batteries, and particularly relates to a method and a device for determining the state of charge of a battery cell, a computer readable storage medium and electronic equipment. The method comprises the steps of obtaining operation data of a battery cell, wherein the operation data of the battery cell at least comprise voltage and current, carrying out parameter identification on a target equivalent circuit model based on the operation data of the battery cell, and constructing a state space model of the battery cell in a current operation state according to a parameter identification result, wherein the target equivalent circuit model is constructed on the basis of a basic equivalent circuit model, carrying out joint estimation on correction parameters of polarized voltage and the state of charge of the battery cell based on the operation data of the battery cell and the state space model to obtain the state of charge of the battery cell, and correcting the polarized voltage in the basic equivalent circuit model by the correction parameters of the polarized voltage to obtain target polarized voltages of the state space model in different operation states.

Inventors

  • XU RUILONG
  • Wu Miaoyuan
  • Jin Qiujin

Assignees

  • 宁德时代未来能源(上海)研究院有限公司
  • 宁德时代新能源科技股份有限公司

Dates

Publication Date
20260508
Application Date
20241105

Claims (17)

  1. 1.A method for determining a state of charge of a battery cell, comprising: acquiring operation data of an electric core, wherein the operation data of the electric core at least comprises voltage and current; Performing parameter identification on a target equivalent circuit model based on the operation data of the battery cell, and constructing a state space model of the battery cell in the current operation state according to a parameter identification result, wherein the target equivalent circuit model is constructed on the basis of a basic equivalent circuit model; Based on the operation data of the battery cell and the state space model, carrying out joint estimation on the correction parameters of the polarization voltage and the state of charge of the battery cell to obtain the state of charge of the battery cell; the correction parameters of the polarization voltage are used for correcting the polarization voltage in the basic equivalent circuit model to obtain target polarization voltages of the state space model in different running states, and the target polarization voltages are used for estimating the correction parameters of the polarization voltage and the charge states of the battery cells.
  2. 2. The method for determining the state of charge of the battery cell according to claim 1, wherein the performing joint estimation on the correction parameter of the polarization voltage and the state of charge of the battery cell based on the operation data of the battery cell and the state space model to obtain the state of charge of the battery cell includes: Performing output prediction based on the state space model and the target polarization voltage at the previous moment to obtain output prediction data at the current moment; Determining a prediction residual error between the operation data of the battery cell and the output prediction data at the current moment; And estimating the correction parameter of the polarization voltage at the current moment and the charge state of the battery cell at the current moment based on the prediction residual error to obtain the correction parameter of the polarization voltage at the current moment and the charge state of the battery cell at the current moment.
  3. 3. The method according to claim 2, wherein estimating the correction parameter of the polarization voltage at the current time and the state of charge of the battery cell at the current time based on the prediction residual error, to obtain the correction parameter of the polarization voltage at the current time and the state of charge of the battery cell at the current time, includes: determining a gain value of a correction parameter of the polarization voltage and a gain value of the state of charge of the battery cell based on the prediction residual; Predicting the correction parameters of the polarization voltage at the current moment and the state of charge of the battery cell at the current moment based on the operation data of the battery cell, the correction parameters of the polarization voltage at the previous moment and the state of charge of the battery cell at the previous moment to obtain a predicted value of the correction parameters of the polarization voltage at the current moment and a predicted value of the state of charge of the battery cell at the current moment; Determining the correction parameter of the polarization voltage at the current moment based on the predicted value of the correction parameter of the polarization voltage at the current moment and the gain value of the correction parameter of the polarization voltage; And determining the state of charge of the battery cell at the current moment based on the predicted value of the state of charge of the battery cell at the current moment and the gain value of the state of charge of the battery cell.
  4. 4. A state of charge determining method according to any one of claims 1 to 3, wherein the construction process of the target equivalent circuit model includes: Determining the basic equivalent circuit model; Correcting the polarization voltage in the basic equivalent circuit model based on a preset polarization correction sub-model to obtain a target polarization voltage, wherein the polarization correction sub-model is used for representing the mapping relation between the polarization voltage and the target polarization voltage; And correcting the polarization voltage in the basic equivalent circuit model to the target polarization voltage based on the basic equivalent circuit model to construct the target equivalent circuit model.
  5. 5. The method according to any one of claims 1 to 4, wherein the correction parameter of the polarization voltage includes a linear correction parameter, a quadratic transformation correction parameter, or a higher order transformation correction parameter.
  6. 6. The state of charge determining method according to claim 5, wherein in the case where the correction parameter of the polarization voltage is the linear correction parameter, the correction process of the polarization voltage includes: And carrying out linear transformation correction on the polarization voltage based on the linear correction parameters to obtain the target correction voltage.
  7. 7. The state of charge determining method according to claim 6, wherein the performing linear transformation correction on the polarization voltage based on the linear correction parameter to obtain the target correction voltage includes: proportional conversion is carried out on the polarization voltage based on the proportional parameter in the linear correction parameters, so that proportional correction voltage is obtained; and carrying out bias superposition on the proportional correction voltage based on the bias parameter in the linear correction parameters to obtain the target correction voltage.
  8. 8. The state of charge determination method according to any one of claims 1 to 7, wherein the parameter identification of the target equivalent circuit model based on the operation data of the battery cell includes: determining terminal voltage errors, terminal voltage error change rates and current change rates of the battery cells based on the operation data of the battery cells; performing online fuzzy reasoning on the terminal voltage error, the terminal voltage error change rate and the current change rate through a fuzzy controller to obtain a forgetting factor; performing on-line parameter identification on the target equivalent circuit model by using a recursive least square algorithm carrying forgetting factors to obtain model parameters of the target equivalent circuit model; and determining parameters of the state space model based on the model parameters of the target equivalent circuit model.
  9. 9. The state of charge determination method according to any one of claims 1 to 8, wherein the parameter identification process and the state estimation process are run iteratively with each other, a result of the parameter identification process being an input to the state estimation process, and a result of the state estimation process being an input to the parameter identification process.
  10. 10. A method of determining a state of charge of a battery, comprising: Determining the state of charge of each cell in the battery based on the state of charge determining method according to any one of claims 1 to 9, respectively; and determining the charge state of the battery according to the charge states of the battery cells.
  11. 11. The state of charge determining method according to claim 10, wherein the determining the state of charge of the battery from the states of charge of the respective battery cells includes: Selecting a charge state maximum value and a charge state minimum value from the charge states of the battery cells; and determining the state of charge of the battery according to the state of charge maximum value and the state of charge minimum value.
  12. 12. A state of charge determining device for a battery cell, comprising: The device comprises an acquisition module, a control module and a control module, wherein the acquisition module is used for acquiring the operation data of the battery cell, and the operation data of the battery cell at least comprises voltage and current; the parameter identification module is used for carrying out parameter identification on a target equivalent circuit model based on the operation data of the battery cell and constructing a state space model of the battery cell in the current operation state according to a parameter identification result, wherein the target equivalent circuit model is constructed on the basis of a basic equivalent circuit model; The joint estimation module is used for carrying out joint estimation on the correction parameters of the polarization voltage and the state of charge of the battery cell based on the operation data of the battery cell and the state space model to obtain the state of charge of the battery cell; the correction parameters of the polarization voltage are used for correcting the polarization voltage in the basic equivalent circuit model to obtain target polarization voltages of the state space model in different running states, and the target polarization voltages are used for estimating the correction parameters of the polarization voltage and the charge states of the battery cells.
  13. 13. The state of charge determining apparatus of claim 12, wherein the joint estimation module comprises: The output prediction sub-module is used for carrying out output prediction based on the state space model and the target polarization voltage at the previous moment to obtain output prediction data at the current moment; a prediction residual determination submodule, configured to determine a prediction residual between the operation data of the battery cell and the output prediction data at the current time; And the state estimation sub-module is used for estimating the correction parameter of the polarization voltage at the current moment and the state of charge of the battery cell at the current moment based on the prediction residual error to obtain the correction parameter of the polarization voltage at the current moment and the state of charge of the battery cell at the current moment.
  14. 14. The state of charge determining device of claim 13, wherein the state estimation submodule includes: a gain value determining unit, configured to determine a gain value of a correction parameter of the polarization voltage and a gain value of a state of charge of the battery cell based on the prediction residual; The state prediction unit is used for predicting the correction parameter of the polarization voltage at the current moment and the state of charge of the battery cell at the current moment based on the operation data of the battery cell, the correction parameter of the polarization voltage at the previous moment and the state of charge of the battery cell at the previous moment to obtain a predicted value of the correction parameter of the polarization voltage at the current moment and a predicted value of the state of charge of the battery cell at the current moment; the state estimation unit is used for determining the correction parameter of the polarization voltage at the current moment based on the predicted value of the correction parameter of the polarization voltage at the current moment and the gain value of the correction parameter of the polarization voltage, and determining the state of charge of the battery cell at the current moment based on the predicted value of the state of charge of the battery cell at the current moment and the gain value of the state of charge of the battery cell.
  15. 15. The state of charge determining device according to any one of claims 12 to 14, characterized in that the state of charge determining device further comprises: the basic equivalent circuit model determining module is used for determining the basic equivalent circuit model; The polarization voltage correction module is used for correcting the polarization voltage in the basic equivalent circuit model based on a preset polarization correction sub-model to obtain a target polarization voltage, wherein the polarization correction sub-model is used for representing the mapping relation between the polarization voltage and the target polarization voltage; And the target equivalent circuit model building module is used for correcting the polarization voltage in the basic equivalent circuit model into the target polarization voltage based on the basic equivalent circuit model so as to build the target equivalent circuit model.
  16. 16. A computer readable storage medium storing a computer program, characterized in that the computer program when executed by a processor implements the steps of the state of charge determination method according to any one of claims 1 to 11.
  17. 17. An electronic device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that the processor implements the steps of the state of charge determination method according to any one of claims 1 to 11 when the computer program is executed.

Description

Method and device for determining charge state of battery cell, storage medium and electronic equipment Technical Field The application belongs to the technical field of batteries, and particularly relates to a method and a device for determining the state of charge of a battery cell, a computer readable storage medium and electronic equipment. Background Accurate State of Charge (SOC) estimation is very important for management and use of the battery, and can improve efficiency and life of the battery, and use safety of the battery. However, the SOC cannot be directly measured, and factors such as the operating temperature, the charge-discharge current, the cycle number, and the self-discharge affect the accuracy of the SOC, and difficulty is brought to estimation of the SOC. In the prior art, SOC estimation can be performed by an ampere-hour integration method, an open-circuit voltage method, an internal resistance method, a discharge experiment method, a neural network method, a kalman filtering method and other methods, and all the methods have respective advantages and disadvantages and application scenes, but in practical application, when a battery is in a scene with a large change in an operating state (such as temperature) and the like, the actual capacity of the battery is changed due to the change of the operating state, and the uncertainty of the capacity finally leads to inaccurate SOC estimation results. Disclosure of Invention In view of this, the embodiments of the present application provide a method, an apparatus, a computer readable storage medium, and an electronic device for determining a state of charge of a battery cell, so as to solve the problem in the prior art that an SOC estimation result is inaccurate in a scene with a large change in an operating state. A first aspect of an embodiment of the present application provides a method for determining a state of charge of a battery cell, which may include: acquiring operation data of the battery cell, wherein the operation data of the battery cell at least comprises voltage and current; Performing parameter identification on a target equivalent circuit model based on the operation data of the battery cell, and constructing a state space model of the battery cell in the current operation state according to the parameter identification result, wherein the target equivalent circuit model is constructed on the basis of a basic equivalent circuit model; Based on the operation data and the state space model of the battery cell, carrying out joint estimation on the correction parameters of the polarization voltage and the charge state of the battery cell to obtain the charge state of the battery cell; The method comprises the steps of obtaining a state space model, wherein a polarization voltage correction parameter is used for correcting the polarization voltage in a basic equivalent circuit model to obtain target polarization voltages of the state space model in different running states, and the target polarization voltages are used for estimating the polarization voltage correction parameter and the charge state of a battery cell. By the method, the polarization voltage in the basic equivalent circuit model can be corrected, so that the target polarization voltage which can adapt to the change of the running state is obtained, the parameter identification and the state estimation are carried out on the basis, the method has strong adaptability even in the scene with large change of the running state, and a more accurate state of charge estimation result can be obtained. In a specific implementation manner of the first aspect, based on the operation data and the state space model of the battery cell, performing joint estimation on the correction parameter of the polarization voltage and the state of charge of the battery cell to obtain the state of charge of the battery cell may include: Output prediction is carried out based on the state space model and the target polarization voltage at the previous moment, so that output prediction data at the current moment is obtained; Determining a prediction residual error between the operation data of the battery cell and the output prediction data at the current moment; And estimating the correction parameter of the polarization voltage at the current moment and the state of charge of the battery cell at the current moment based on the prediction residual error to obtain the correction parameter of the polarization voltage at the current moment and the state of charge of the battery cell at the current moment. By the method, output prediction and residual calculation are performed based on the target polarization voltage which can adapt to the running state change, the obtained prediction residual can also adapt to the running state change, and state estimation is performed based on the prediction residual, so that a more accurate estimation result can be obtained. In a specific implementation man