CN116068405A - Parameter fitting method and device based on RC fitting model of power battery - Google Patents

Parameter fitting method and device based on RC fitting model of power battery Download PDF

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Publication number
CN116068405A
CN116068405A CN202211735308.1A CN202211735308A CN116068405A CN 116068405 A CN116068405 A CN 116068405A CN 202211735308 A CN202211735308 A CN 202211735308A CN 116068405 A CN116068405 A CN 116068405A
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fitting
parameter
power battery
charge
voltage
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徐龑昕
辛龙威
陈佶
尚梦瑶
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Hubei Eve Power Co Ltd
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Hubei Eve Power Co Ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/367—Software therefor, e.g. for battery testing using modelling or look-up tables
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/385—Arrangements for measuring battery or accumulator variables

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Abstract

The invention discloses a parameter fitting method and device based on a power battery RC fitting model, which are characterized in that the RC fitting parameters of power battery cells are analyzed and calculated by combining the collected observed voltage, current and charge state in the discharge time with a first-order Thevenin equivalent model, so that the calculation speed of the RC fitting parameters of the battery cells can be improved, the RC fitting parameters can be conveniently transplanted into a singlechip for operation, and the program operation blocking phenomenon is reduced; and after multiple calculation iterations, the calculation accuracy of RC fitting parameters is greatly improved, and good conditions are provided for the development of a battery management system of a subsequent power battery.

Description

Parameter fitting method and device based on RC fitting model of power battery
Technical Field
The invention relates to the technical field of batteries, in particular to a parameter fitting method and device based on a power battery RC fitting model.
Background
Currently, the calculation of a battery management system of a mainstream power battery mostly adopts an open circuit voltage method, an ampere-hour integration method, a kalman filtering method, a neural network method and the like. The open-circuit voltage method only considers the corresponding relation of rated working conditions in a static state, and errors are larger and larger along with the extension of the running time; the ampere-hour integration method has extremely high requirements on the current precision, cannot fully consider internal resistance, temperature, aging factors and the like, is difficult to estimate accurately, and under the condition of high temperature or severe current fluctuation, the capacity of the battery can change, and the accurate result is difficult to obtain only by using the method; the neural network method needs sample training, and has large calculated amount and high requirement on hardware; the most important in the kalman filtering method is the accuracy of the battery performance model and the computing power of the battery management system. In order to solve the defects of an open circuit voltage method, an ampere-hour integration method, a Kalman filtering method and a neural network method, the parameter fitting of an RC equivalent circuit model is generated, and reliable RC fitting parameters can be effectively provided for a battery management system of a power battery.
However, practice finds that the RC parameter fitting is mainly performed by two or three steps at present, and the larger the order is, the stronger the required computing capacity is, the battery management system mainly operates by a singlechip, and the conditions of incapability of timely reacting a computing result, program operation blocking and the like may be caused by excessive operation amount. Therefore, it is important to provide a technical scheme how to increase the calculation speed of the RC fitting parameters of the battery cells.
Disclosure of Invention
The invention provides a parameter fitting method and device based on a power battery RC fitting model, which can improve the calculation speed of battery cell RC fitting parameters.
To solve the above technical problems, the first aspect of the present invention discloses a parameter fitting method based on a power battery RC fitting model, the method comprising:
acquiring current, observed voltage and target state of charge in a certain discharge time period in the discharging process of the power battery cell, and determining a resistance fitting parameter and a capacitance fitting parameter to be calculated of the power battery cell;
constructing an electrical parameter analysis function according to the resistance fitting parameter, the capacitance fitting parameter, the current, the discharge duration, the observed voltage and the target state of charge, and establishing an RC fitting model corresponding to the power battery cell based on the electrical parameter analysis function and a first-order Thevenin model;
And analyzing the resistance fitting parameter, the capacitance fitting parameter, the current, the discharge duration, the observed voltage and the target state of charge based on the established RC fitting model corresponding to the power battery cell to obtain the resistance fitting parameter and the capacitance fitting parameter of the power battery cell.
In an optional implementation manner, in a first aspect of the present invention, the analyzing, based on the established RC fitting model corresponding to the power battery cell, the resistance fitting parameter, the capacitance fitting parameter, the current, the discharge duration, the observed voltage, and the target state of charge, to obtain the resistance fitting parameter and the capacitance fitting parameter of the power battery cell includes:
calculating a target open-circuit voltage of the target state of charge according to the determined fitting curve of the state of charge-open-circuit voltage, and calculating a first voltage difference between the target open-circuit voltage and the observed voltage;
and respectively setting corresponding initial estimated values for the resistance fitting parameters and the capacitance fitting parameters, and analyzing the resistance fitting parameters with the initial estimated values, the capacitance fitting parameters with the initial estimated values, the current and the first voltage difference based on the established RC fitting model corresponding to the power battery cell to obtain the resistance fitting parameters and the capacitance fitting parameters of the power battery cell.
As an alternative embodiment, in the first aspect of the present invention, the method further includes:
a plurality of first charge states of the power battery cell and open-circuit voltages corresponding to the first charge states are acquired at intervals, and each first charge state is acquired by standing for a preset period of time after the power battery cell stops discharging at the time;
and fitting each first charge state and the open-circuit voltage corresponding to the first charge state to obtain a fit curve of the charge state-open-circuit voltage of the power battery cell.
As an optional implementation manner, in the first aspect of the present invention, after the analyzing the resistance fitting parameter, the capacitance fitting parameter, the current, the discharge duration, the observed voltage, and the target state of charge based on the established RC fitting model corresponding to the power battery cell, the method further includes:
and inputting the resistance fitting parameters and the capacitance fitting parameters into the first-order Thevenin model and the RC fitting model for analysis, and obtaining analysis results output by the first-order Thevenin model and the RC fitting model as fitting voltages of the power battery cells, wherein the fitting voltages of the power battery cells are used for evaluating fitting conditions of the fitting curve of the state-of-charge-open-circuit voltage and/or evaluating fitting conditions of the resistance fitting parameters and the capacitance fitting parameters.
As an alternative embodiment, in the first aspect of the present invention, the method further includes:
calculating a second voltage difference between the fitting voltage and the observed voltage, and judging whether the second voltage difference is smaller than or equal to a preset voltage difference value;
and when the judgment result is yes, updating the calculated resistance fitting parameter and the calculated voltage fitting parameter to respectively set corresponding initial estimated values for the resistance fitting parameter and the capacitance fitting parameter, and re-executing the operations of analyzing the resistance fitting parameter, the capacitance fitting parameter, the current and the first voltage difference with the initial estimated values set on the basis of the established RC fitting model corresponding to the power battery cell to obtain the resistance fitting parameter and the capacitance fitting parameter of the power battery cell.
As an alternative embodiment, in the first aspect of the present invention, the method further includes:
judging whether a correction operation is required to be executed on the fitting curve of the state of charge-open circuit voltage, and when the judgment result is yes, monitoring the electric quantity stationary phase of the power battery cell, and collecting a plurality of second states of charge in the electric quantity stationary phase and open circuit voltages corresponding to each second state of charge;
And fitting each second charge state and the open-circuit voltage corresponding to the second charge state to obtain a charge state-open-circuit voltage fitting curve of the power battery cell, wherein the charge state-open-circuit voltage fitting curve is used as a required charge state-open-circuit voltage fitting curve.
As an optional implementation manner, in the first aspect of the present invention, the determining whether a correction operation needs to be performed on the fitted curve of the state of charge-open circuit voltage includes:
calculating the coincidence degree of the fitting curve of the charge state-open circuit voltage and the fitting curve of the preset charge state-open circuit voltage of the battery core of the power battery, judging whether the coincidence degree is smaller than or equal to a preset coincidence degree threshold value, and determining that correction operation is required to be executed on the fitting curve of the charge state-open circuit voltage when the judgment result is negative; or alternatively, the process may be performed,
and calculating a second voltage difference between the fitting voltage and the observed voltage, judging whether the second voltage difference is smaller than or equal to a preset voltage difference value, and determining that correction operation is required to be executed on the fitting curve of the charge state-open circuit voltage when the judgment result is negative.
The second aspect of the invention discloses a parameter fitting device based on a RC fitting model of a power battery, which comprises:
The acquisition module is used for acquiring current, observed voltage and target state of charge in a certain discharge time period in the discharging process of the battery cell of the power battery;
the determining module is used for determining a resistance fitting parameter and a capacitance fitting parameter which need to be calculated for the power battery cell;
the establishing module is used for establishing an electric parameter analysis function according to the resistance fitting parameter, the capacitance fitting parameter, the current, the discharge duration, the observed voltage and the target state of charge, and establishing an RC fitting model corresponding to the power battery cell based on the electric parameter analysis function and a first-order Thevenin model which is determined in advance;
and the analysis module is used for analyzing the resistance fitting parameter, the capacitance fitting parameter, the current, the discharge duration, the observed voltage and the target state of charge based on the established RC fitting model corresponding to the power battery cell to obtain the resistance fitting parameter and the capacitance fitting parameter of the power battery cell.
In a second aspect of the present invention, the specific manner of the analyzing module analyzing the resistance fitting parameter, the capacitance fitting parameter, the current, the discharge duration, the observed voltage and the target state of charge based on the established RC fitting model corresponding to the power battery cell, to obtain the resistance fitting parameter and the capacitance fitting parameter of the power battery cell includes:
Calculating a target open-circuit voltage of the target state of charge according to the determined fitting curve of the state of charge-open-circuit voltage, and calculating a first voltage difference between the target open-circuit voltage and the observed voltage;
and respectively setting corresponding initial estimated values for the resistance fitting parameters and the capacitance fitting parameters, and analyzing the resistance fitting parameters with the initial estimated values, the capacitance fitting parameters with the initial estimated values, the current and the first voltage difference based on the established RC fitting model corresponding to the power battery cell to obtain the resistance fitting parameters and the capacitance fitting parameters of the power battery cell.
In a second aspect of the present invention, the obtaining module is further configured to obtain, at intervals, a plurality of first states of charge of the power battery cell and an open circuit voltage corresponding to each of the first states of charge, where each of the first states of charge is collected by standing for a preset period of time after the power battery cell stops discharging at a time;
the apparatus further comprises:
and the first fitting module is used for fitting each first charge state and the open-circuit voltage corresponding to the first charge state to obtain a fit curve of the charge state-open-circuit voltage of the power battery cell.
As an optional implementation manner, in the second aspect of the present invention, the analysis module is further configured to, based on an RC fitting model corresponding to the power battery cell, analyze the resistance fitting parameter, the capacitance fitting parameter, the current, the discharge duration, the observed voltage, and the target state of charge, and input the resistance fitting parameter and the capacitance fitting parameter into the first-order davin model for analysis;
the acquisition module is further configured to acquire an analysis result output by the first-order davin model as a fitting voltage of the power battery cell, where the fitting voltage of the power battery cell is used to evaluate a fitting condition of the fitting curve of the state of charge-open circuit voltage and/or to evaluate a fitting condition of the resistance fitting parameter and the capacitance fitting parameter.
As an alternative embodiment, in the second aspect of the present invention, the apparatus further includes:
the calculation module is used for calculating a second voltage difference between the fitting voltage and the observed voltage;
the first judging module is used for judging whether the second voltage difference is smaller than or equal to a preset voltage difference value;
And the updating module is used for updating the calculated resistance fitting parameter and the calculated voltage fitting parameter to respectively set corresponding initial estimated values for the resistance fitting parameter and the capacitance fitting parameter when the judgment result of the first judgment module is yes, triggering the analysis module to re-execute the operations of analyzing the resistance fitting parameter, the capacitance fitting parameter, the current and the first voltage difference with the initial estimated values set on the basis of the established RC fitting model corresponding to the power battery cell, so as to obtain the resistance fitting parameter and the capacitance fitting parameter of the power battery cell.
As an alternative embodiment, in the second aspect of the present invention, the apparatus further includes:
the second judging module is used for judging whether the fitting curve of the charge state-open circuit voltage needs to be corrected;
the monitoring module is used for monitoring the electric quantity stationary phase of the power battery core when the judgment result is yes;
the acquisition module is also used for acquiring a plurality of second charge states in the electric quantity stable period and open-circuit voltages corresponding to each second charge state;
The second fitting module is further configured to fit each second state of charge and an open-circuit voltage corresponding to the second state of charge, so as to obtain a fitting curve of the state of charge-open-circuit voltage of the power battery cell, and the fitting curve is used as a fitting curve of the required state of charge-open-circuit voltage.
In a second aspect of the present invention, the method for determining whether the correction operation needs to be performed on the fitted curve of the state of charge-open circuit voltage by the second determining module specifically includes:
calculating the coincidence degree of the fitting curve of the charge state-open circuit voltage and the fitting curve of the preset charge state-open circuit voltage of the battery core of the power battery, judging whether the coincidence degree is smaller than or equal to a preset coincidence degree threshold value, and determining that correction operation is required to be executed on the fitting curve of the charge state-open circuit voltage when the judgment result is negative; or alternatively, the process may be performed,
and calculating a second voltage difference between the fitting voltage and the observed voltage, judging whether the second voltage difference is smaller than or equal to a preset voltage difference value, and determining that correction operation is required to be executed on the fitting curve of the charge state-open circuit voltage when the judgment result is negative.
In a third aspect, the invention discloses another parameter fitting device based on a RC fitting model of a power battery, which comprises:
a memory storing executable program code;
a processor coupled to the memory;
the processor invokes the executable program code stored in the memory to perform some or all of the steps of any of the power cell RC fitting model-based parameter fitting methods disclosed in the first aspect of the invention.
A fourth aspect of the invention discloses a computer storage medium storing computer instructions which, when invoked, are adapted to perform part or all of the steps of any of the power cell RC fitting model-based parameter fitting methods disclosed in the first aspect of the invention.
Compared with the prior art, the embodiment of the invention has the following beneficial effects:
in the embodiment of the invention, the current, the observed voltage and the target state of charge in a certain discharging time period in the discharging process of the power battery cell are obtained, and the resistance fitting parameter and the capacitance fitting parameter which need to be calculated of the power battery cell are determined; constructing an electrical parameter analysis function according to the resistance fitting parameters, the capacitance fitting parameters, the current, the discharge duration, the observed voltage and the target state of charge, and constructing an RC fitting model corresponding to the battery cell of the power battery based on the electrical parameter analysis function and a first-order Thevenin model which is determined in advance; and analyzing the resistance fitting parameter with the initial estimated value, the capacitance fitting parameter with the initial estimated value, the current and the first voltage difference based on the RC fitting model corresponding to the built power battery cell to obtain the resistance fitting parameter and the capacitance fitting parameter of the power battery cell. Therefore, the RC fitting parameters of the battery cells of the power battery are analyzed and calculated by combining the collected observed voltage, current and charge state in the discharge time with the first-order Thevenin equivalent model, so that the calculation speed of the RC fitting parameters of the battery cells can be improved, the RC fitting parameters can be conveniently transplanted into a singlechip for operation, and the program operation clamping phenomenon is reduced; and after multiple calculation iterations, the calculation accuracy of RC fitting parameters is greatly improved, and good conditions are provided for the development of a battery management system of a subsequent power battery.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a parameter fitting method based on a RC fitting model of a power battery according to an embodiment of the present invention;
FIG. 2 is a flow chart of another method of parameter fitting based on a RC fitting model of a power battery according to an embodiment of the present disclosure;
FIG. 3 is a schematic flow chart of a parameter fitting device based on a RC fitting model of a power battery according to an embodiment of the present invention
FIG. 4 is a schematic structural diagram of another parameter fitting device based on a RC fitting model of a power battery according to an embodiment of the present invention;
FIG. 5 is a schematic structural diagram of a parameter fitting device based on a RC fitting model of a power battery according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of a first-order davin model according to an embodiment of the present invention.
Detailed Description
In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The terms first, second and the like in the description and in the claims and in the above-described figures are used for distinguishing between different objects and not necessarily for describing a sequential or chronological order. Furthermore, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, apparatus, article, or article that comprises a list of steps or elements is not limited to only those listed but may optionally include other steps or elements not listed or inherent to such process, method, article, or article.
Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.
The invention discloses a parameter fitting method and device based on a power battery RC fitting model, which are characterized in that the RC fitting parameters of power battery cells are analyzed and calculated by combining the collected observed voltage, current and charge state in the discharge time with a first-order Thevenin equivalent model, so that the calculation speed of the RC fitting parameters of the battery cells can be improved, the RC fitting parameters can be conveniently transplanted into a singlechip for operation, and the program operation blocking phenomenon is reduced; and after multiple calculation iterations, the calculation accuracy of RC fitting parameters is greatly improved, and good conditions are provided for the development of a battery management system of a subsequent power battery. The following will explain in detail.
Example 1
Referring to fig. 1, fig. 1 is a flow chart of a parameter fitting method based on an RC fitting model of a power battery according to an embodiment of the present invention. The method described in fig. 1 can be applied to a parameter fitting device based on a power battery RC fitting model, wherein the parameter fitting device comprises one or more of a parameter fitting server, a parameter fitting service device and a parameter fitting service system. As shown in fig. 1, the parameter fitting method based on the power battery RC fitting model may include the following operations:
101. And acquiring current, observed voltage and target state of charge in a certain discharge time in the discharging process of the battery cell of the power battery.
In the embodiment of the invention, the power battery is any battery needing RC parameter fitting.
102. And determining the resistance fitting parameters and the capacitance fitting parameters required to be calculated by the battery cells of the power battery.
103. And constructing an electrical parameter analysis function according to the resistance fitting parameter, the capacitance fitting parameter, the current, the discharge duration, the observed voltage and the target state of charge.
In the embodiment of the invention, optionally, according to the determined fitting curve of the charge state-open circuit voltage, calculating the target open circuit voltage of the target charge state, calculating the first voltage difference between the target open circuit voltage and the observed voltage, and constructing an electrical parameter analysis function according to the first voltage difference, the discharge duration, the absolute value of the current, the resistance fitting parameter and the capacitance fitting parameter.
104. And establishing an RC fitting model corresponding to the power battery cell based on the electrical parameter analysis function and a predetermined first-order Thevenin model.
In the embodiment of the invention, optionally, the electrical parameter analysis function is: v (V) oc ＝P((R 0 R p C p ),V oc I (k), (t (k) -t (k-1)); and the first-order Thevenin model is shown in FIG. 6, FIG. 6 is a schematic diagram of the structure of the first-order Thevenin model according to the embodiment of the invention, R p And C p Parallel, R 0 R is connected in parallel with p 、C p Serial connection; and, optionally, the RC fitting model is composed as follows:
V＝i(k)R 0 +V p (k)-V oc ；
V p (k)＝V p (k-i)M+(1-M)R p i(k)；
M＝e -m(t(k)-t(k-1)) ；
m＝1/R p C p ；
wherein R is 0 A first sub-parameter of the resistance fitting parameter for the power battery cell, R p Fitting a second sub-parameter of the parameters for the resistance of the power cell, C p Fitting parameters for the capacitance of the power battery cell, wherein R 0 R is connected in parallel with p 、C p Serial connection; v is the observed voltage of the battery cell of the power battery; v (V) oc The target open-circuit voltage of the power battery cell; i (k) is the current of the power battery cell at the discharging moment k; v (V) p (k) R at discharging time k for power battery cell p And C p Fitting voltage formed; v (V) p (k-i) is R of the power battery cell at the discharging time k-1 p And C p Fitting voltage formed; t (k) -t (k-1) is the discharge duration.
105. And analyzing the resistance fitting parameter, the capacitance fitting parameter, the current, the discharge duration, the observed voltage and the target state of charge based on the established RC fitting model corresponding to the power battery cell to obtain the resistance fitting parameter and the capacitance fitting parameter of the power battery cell.
In the embodiment of the present invention, optionally, the parameters in step 105 are analyzed in combination with the lsqnonlin function to obtain the resistance fitting parameter and the capacitance fitting parameter.
Therefore, the implementation of the parameter fitting method based on the RC fitting model of the power battery described in FIG. 1 can analyze and calculate the RC fitting parameters of the battery cells of the power battery by combining the acquired observed voltage, current and state of charge in the discharge time with the first-order Thevenin equivalent model, can improve the calculation speed of the RC fitting parameters of the battery cells, is convenient to be transplanted into a singlechip for calculation, and reduces the program operation clamping phenomenon; and after multiple calculation iterations, the calculation accuracy of RC fitting parameters is greatly improved, and good conditions are provided for the development of a battery management system of a subsequent power battery.
In an alternative embodiment, based on the established RC fitting model corresponding to the power battery cell, the resistance fitting parameter, the capacitance fitting parameter, the current, the discharge duration, the observed voltage, and the target state of charge are analyzed to obtain the resistance fitting parameter and the capacitance fitting parameter of the power battery cell, including:
calculating a target open-circuit voltage of a target state of charge according to the determined fitting curve of the state of charge-open-circuit voltage, and calculating a first voltage difference between the target open-circuit voltage and the observed voltage;
and respectively setting corresponding initial estimated values for the resistance fitting parameters and the capacitance fitting parameters, and analyzing the resistance fitting parameters with the initial estimated values, the capacitance fitting parameters with the initial estimated values, the current and the first voltage difference based on the established RC fitting model corresponding to the power battery cells to obtain the resistance fitting parameters and the capacitance fitting parameters of the power battery cells.
In the embodiment of the invention, the resistance fitting parameter and the capacitance fitting parameter (R 0 、R p And C p ) Setting corresponding upper and lower bounds, such as: the lower bound is [0,0]The upper bound is [1,1,10000000 ]]。
Therefore, according to the alternative embodiment, the open-circuit voltage of the charge state of the observed power battery cell is calculated by combining the fit curve of the charge state-open-circuit voltage, so that the calculation accuracy and efficiency of the open-circuit voltage can be improved, the calculated voltage difference between the open-circuit voltage and the observed voltage, the initial estimated value of the parameter to be fitted and the observed current are analyzed by utilizing the established RC fitting parameter model, and the resistance and capacitance fitting parameters of the power battery cell can be accurately and efficiently analyzed.
In another alternative embodiment, the method may further comprise the steps of:
acquiring a plurality of first charge states of the power battery cell and open-circuit voltages corresponding to the first charge states at intervals, wherein each first charge state is acquired by standing for a preset period of time after the power battery cell stops discharging at the present time;
and fitting each first charge state and the open-circuit voltage corresponding to the first charge state to obtain a fit curve of the charge state-open-circuit voltage of the battery cell of the power battery.
In this optional embodiment, optionally, after the first state of charge of the power battery cell and the corresponding open-circuit voltage are obtained, the power battery cell is continuously discharged to the preset voltage, and then the power battery cell is left for a preset period of time, and then the current first state of charge and the corresponding open-circuit voltage are collected. It should be noted that the interval duration of each collection of the state of charge may be equal or unequal. And further, when the first state of charge of the power battery cell is acquired to be 0, stopping acquiring the first state of charge of the power battery cell.
In this alternative embodiment, after all the first states of charge and the corresponding open circuit voltages are obtained, a fitting curve of states of charge-open circuit voltages of the power battery cells is obtained based on Matlab and by selecting an n-order (e.g., 9-order) polynomial equation for fitting.
Therefore, according to the alternative embodiment, the plurality of charge states of the power battery cells obtained at intervals and the corresponding open-circuit voltages are fitted, so that an accurate fit curve of the charge states and the open-circuit voltages can be obtained, and the follow-up efficient and accurate calculation of the open-circuit voltages corresponding to the charge states is facilitated.
In yet another alternative embodiment, the method may further comprise the steps of:
Judging whether a correction operation is required to be executed on a fitting curve of the state of charge and the open circuit voltage, and when the judgment result is yes, monitoring the electric quantity stationary phase of the battery core of the power battery, and collecting a plurality of second states of charge in the electric quantity stationary phase and the open circuit voltage corresponding to each second state of charge;
and fitting each second charge state and the open circuit voltage corresponding to the second charge state to obtain a charge state-open circuit voltage fitting curve of the battery core of the power battery, and taking the charge state-open circuit voltage fitting curve as a required charge state-open circuit voltage fitting curve.
In this alternative embodiment, the present flow is ended when no correction operation is required for the state of charge-open circuit voltage fitted curve.
Therefore, in the optional embodiment, when the fitting curve of the charge state-open circuit voltage is further determined to be required to be corrected, the charge state of the battery cell in the electric quantity stationary period and the corresponding open circuit voltage are collected to be re-fitted, so that the fitting curve of the accurate and reliable charge state-open circuit voltage is obtained, the accurate open circuit voltage is obtained later, and the analysis accuracy of RC fitting parameters is further improved.
In this alternative embodiment, optionally, determining whether a correction operation needs to be performed on the fitted curve of state of charge-open circuit voltage includes:
Calculating the coincidence degree of a fitting curve of the charge state-open circuit voltage and a fitting curve of the preset charge state-open circuit voltage of the battery core of the power battery, judging whether the coincidence degree is smaller than or equal to a preset coincidence degree threshold value, and determining that correction operation is required to be executed on the fitting curve of the charge state-open circuit voltage when the judgment result is negative; or alternatively, the process may be performed,
and calculating a second voltage difference between the fitting voltage and the observed voltage, judging whether the second voltage difference is smaller than or equal to a preset voltage difference value, and determining that correction operation is required to be executed on the fitting curve of the charge state-open circuit voltage when the judgment result is negative.
Therefore, in the optional embodiment, when the coincidence ratio of the fitted state of charge-open circuit voltage fitted curve and the preset fitted curve is smaller or the obtained fitted voltage error is larger, the fitted curve of the state of charge-open circuit voltage is determined to be corrected, namely the fitted curve of the state of charge-open circuit voltage is required to be re-fitted, so that the determination efficiency of re-fitting the fitted curve of the state of charge-open circuit voltage is improved.
Example two
Referring to fig. 2, fig. 2 is a flow chart of another parameter fitting method based on an RC fitting model of a power battery according to an embodiment of the invention. The method described in fig. 2 can be applied to a parameter fitting device based on a power battery RC fitting model, wherein the parameter fitting device comprises one or more of a parameter fitting server, a parameter fitting service device and a parameter fitting service system. As shown in fig. 2, the parameter fitting method based on the power battery RC fitting model may include the following operations:
201. And acquiring current, observed voltage and target state of charge in a certain discharge time in the discharging process of the battery cell of the power battery.
202. And determining the resistance fitting parameters and the capacitance fitting parameters required to be calculated by the battery cells of the power battery.
203. And constructing an electrical parameter analysis function according to the resistance fitting parameter, the capacitance fitting parameter, the current, the discharge duration, the observed voltage and the target state of charge.
204. And establishing an RC fitting model corresponding to the power battery cell based on the electrical parameter analysis function and a predetermined first-order Thevenin model.
205. And analyzing the resistance fitting parameter, the capacitance fitting parameter, the current, the discharge duration, the observed voltage and the target state of charge based on the established RC fitting model corresponding to the power battery cell, so as to obtain the resistance fitting parameter and the capacitance fitting parameter of the power battery cell.
206. And inputting the resistance fitting parameters and the capacitance fitting parameters into the first-order Thevenin model and the RC fitting model for analysis, and obtaining analysis results output by the first-order Thevenin model and the RC fitting model as fitting voltages of the power battery cells.
In the embodiment of the invention, the fitting voltage of the battery cell of the power battery is used for evaluating the fitting condition of a fitting curve of the state of charge-open circuit voltage and/or evaluating the fitting condition of a resistance fitting parameter and a capacitance fitting parameter.
It should be noted that, for other related descriptions of step 201 to step 205, please refer to the detailed descriptions of step 101 to step 105 in the first embodiment, and the description of the embodiment of the present invention is omitted.
Therefore, the implementation of the parameter fitting method based on the RC fitting model of the power battery described in FIG. 2 can analyze and calculate the RC fitting parameters of the battery cells of the power battery by combining the acquired observed voltage, current and state of charge in the discharge time with the first-order Thevenin equivalent model, can improve the calculation speed of the RC fitting parameters of the battery cells, is convenient to be transplanted into a singlechip for calculation, and reduces the program operation clamping phenomenon; and after multiple calculation iterations, the calculation accuracy of RC fitting parameters is greatly improved, and good conditions are provided for the development of a battery management system of a subsequent power battery. In addition, after the RC fitting parameters are obtained, the RC fitting parameters are further replaced back into the first-order Thevenin model to obtain the fitting voltage of the battery cells of the power battery, so that the fitting condition of the fitting curve of the charge state-open circuit voltage can be accurately estimated, whether the RC fitting parameters need to be continuously fitted or not is determined, and therefore more accurate fitting parameters are obtained.
In an alternative embodiment, the method may further comprise the steps of:
Calculating a second voltage difference between the fitting voltage and the observed voltage, and judging whether the second voltage difference is smaller than or equal to a preset voltage difference value;
and when the judgment result is yes, updating the calculated resistance fitting parameter and the calculated voltage fitting parameter into the resistance fitting parameter and the capacitance fitting parameter, respectively setting corresponding initial estimated values, and re-executing the operations of the resistance fitting parameter, the capacitance fitting parameter, the current and the first voltage difference according to the set initial estimated values, analyzing the RC fitting model corresponding to the established power battery cell, and obtaining the resistance fitting parameter and the capacitance fitting parameter of the power battery cell.
In this optional embodiment, after the fitting is completed, the capacitance fitting parameter and the resistance fitting parameter that are fitted at the time may be used as initial estimated values thereof to participate in the fitting at the next time until the fitting frequency is greater than or equal to the preset fitting frequency or the fitted fitting parameter tends to be stable. Further, setting parameters for the electrical parameter analysis function allows error values, residue squares.
Therefore, in this optional embodiment, after the fitting voltage of the power battery is obtained, the fitting voltage is further compared with the preset voltage difference value, if the fitting voltage is smaller, the RC fitting parameter obtained at present is used as the initial estimated value to participate in the fitting of the next time, so that the fitting accuracy of the RC fitting parameter of the power battery cell can be further improved.
Example III
Referring to fig. 3, fig. 3 is a schematic structural diagram of a parameter fitting device based on an RC fitting model of a power battery according to an embodiment of the present invention, where the parameter fitting device includes one or more of a parameter fitting server, a parameter fitting service device, and a parameter fitting service system. As shown in fig. 3, the apparatus includes:
the acquisition module 301 is configured to acquire a current, an observed voltage and a target state of charge in a certain discharge time period in a discharging process of the battery cell of the power battery;
the determining module 302 is configured to determine a resistance fitting parameter and a capacitance fitting parameter that need to be calculated for the power battery cell;
the establishing module 303 is configured to construct an electrical parameter analysis function according to the resistance fitting parameter, the capacitance fitting parameter, the current, the discharge duration, the observed voltage and the target state of charge, and establish an RC fitting model corresponding to the power battery cell based on the electrical parameter analysis function and a first-order davin model determined in advance;
the analysis module 304 is configured to analyze the resistance fitting parameter, the capacitance fitting parameter, the current, the discharge duration, the observed voltage, and the target state of charge based on the established RC fitting model corresponding to the power battery cell, so as to obtain the resistance fitting parameter and the capacitance fitting parameter of the power battery cell.
Therefore, the parameter fitting device based on the RC fitting model of the power battery described in the embodiment 3 analyzes and calculates the RC fitting parameters of the battery cells by combining the acquired observed voltage, current and charge state in the discharge time with the first-order Thevenin equivalent model, so that the calculation speed of the RC fitting parameters of the battery cells can be improved, the RC fitting parameters can be conveniently transplanted into a singlechip for operation, and the program operation blocking phenomenon is reduced; and after multiple calculation iterations, the calculation accuracy of RC fitting parameters is greatly improved, and good conditions are provided for the development of a battery management system of a subsequent power battery.
In an alternative embodiment, the analyzing module 304 analyzes the resistance fitting parameter, the capacitance fitting parameter, the current, the discharge duration, the observed voltage and the target state of charge based on the RC fitting model corresponding to the established power battery cell, and the specific ways for obtaining the resistance fitting parameter and the capacitance fitting parameter of the power battery cell include:
calculating a target open-circuit voltage of a target state of charge according to the determined fitting curve of the state of charge-open-circuit voltage, and calculating a first voltage difference between the target open-circuit voltage and the observed voltage;
and respectively setting corresponding initial estimated values for the resistance fitting parameters and the capacitance fitting parameters, and analyzing the resistance fitting parameters with the initial estimated values, the capacitance fitting parameters with the initial estimated values, the current and the first voltage difference based on the established RC fitting model corresponding to the power battery cells to obtain the resistance fitting parameters and the capacitance fitting parameters of the power battery cells.
Therefore, the parameter fitting device based on the RC fitting model of the power battery described in fig. 3 can also be used for calculating the open-circuit voltage of the charge state of the observed power battery cell by combining the fitting curve of the charge state-open-circuit voltage, so that the calculation accuracy and efficiency of the open-circuit voltage can be improved, the calculated voltage difference between the open-circuit voltage and the observed voltage, the initial estimated value of the parameter to be fitted and the observed current can be analyzed by using the established RC fitting parameter model, and the resistance and capacitance fitting parameters of the power battery cell can be accurately and efficiently analyzed.
In another optional embodiment, the obtaining module 301 is further configured to obtain, at intervals, a plurality of first states of charge of the power battery cell and an open circuit voltage corresponding to each first state of charge, where each first state of charge is collected by standing for a preset period of time after the power battery cell stops discharging at a time;
and as shown in fig. 4, the apparatus further includes:
the first fitting module 305 is configured to fit each first state of charge and an open circuit voltage corresponding to the first state of charge to obtain a fit curve of the state of charge of the power battery cell to the open circuit voltage.
Therefore, the parameter fitting device based on the power battery RC fitting model described in fig. 4 can be used for fitting a plurality of states of charge and corresponding open-circuit voltages of the power battery cells acquired at intervals, so that a fitting curve of accurate states of charge-open-circuit voltages can be obtained, and the subsequent efficient and accurate calculation of the open-circuit voltages corresponding to the states of charge is facilitated.
In yet another alternative embodiment, as shown in fig. 4, the analysis module 304 is further configured to analyze the resistance fitting parameter, the capacitance fitting parameter, the current, the discharge duration, the observed voltage, and the target state of charge based on the established RC fitting model corresponding to the power battery cell, and then input the resistance fitting parameter and the capacitance fitting parameter into the first-order dynia model and the RC fitting model for analysis after obtaining the resistance fitting parameter and the capacitance fitting parameter of the power battery cell;
the obtaining module 301 is further configured to obtain an analysis result output by the first-order davin model and the RC fitting model, as a fitting voltage of the power battery cell, where the fitting voltage of the power battery cell is used to evaluate a fitting condition of a fitting curve of a state of charge-open circuit voltage and/or to evaluate a fitting condition of a resistance fitting parameter and a capacitance fitting parameter.
It can be seen that, the parameter fitting device based on the RC fitting model of the power battery described in fig. 4 can further obtain the fitting voltage of the power battery cell by replacing the RC fitting parameter with the first-order davin model after obtaining the RC fitting parameter, so as to accurately evaluate the fitting condition of the fitting curve of the state of charge-open circuit voltage and determine whether to continue fitting the RC fitting parameter, thereby obtaining a more accurate fitting parameter.
In yet another alternative embodiment, as shown in fig. 4, the apparatus further comprises:
a calculation module 306, configured to calculate a second voltage difference between the fitting voltage and the observed voltage;
a first judging module 307, configured to judge whether the second voltage difference is less than or equal to a preset voltage difference;
and the updating module 308 is configured to update the calculated resistance fitting parameter and the calculated voltage fitting parameter to initial estimated values corresponding to the resistance fitting parameter and the capacitance fitting parameter, and trigger the analysis module 304 to re-execute the operations of analyzing the RC fitting model corresponding to the built power battery cell according to the resistance fitting parameter, the capacitance fitting parameter, the current and the first voltage difference with the initial estimated values set, and obtain the resistance fitting parameter and the capacitance fitting parameter of the power battery cell when the first judging module 307 judges that the result is yes.
It can be seen that, the parameter fitting device based on the RC fitting model of the power battery described in fig. 4 can further compare the obtained fitting voltage of the power battery with the preset voltage difference value, and if the obtained RC fitting parameter is smaller, the RC fitting parameter obtained at present is used as the initial estimated value to participate in the next fitting, so that the fitting accuracy of the RC fitting parameter of the battery cell of the power battery can be further improved.
In yet another alternative embodiment, as shown in fig. 4, the apparatus further comprises:
a second judging module 309, configured to judge whether a correction operation needs to be performed on the fitted curve of the state of charge-open circuit voltage;
the monitoring module 310 is configured to monitor a stationary period of an electric quantity of the power battery cell when the determination result is yes;
the acquiring module 301 is further configured to acquire a plurality of second states of charge in the electric quantity stationary period and an open circuit voltage corresponding to each of the second states of charge;
the second fitting module 311 is further configured to fit each second state of charge and an open circuit voltage corresponding to the second state of charge, so as to obtain a fit curve of the state of charge-open circuit voltage of the power battery cell, as a required fit curve of the state of charge-open circuit voltage.
Therefore, the parameter fitting device based on the RC fitting model of the power battery described in FIG. 4 can further acquire the state of charge of the battery cell in the electric quantity stationary phase and the corresponding open-circuit voltage for re-fitting when the fitting curve of the state of charge-open-circuit voltage is determined to be needed, so that the fitting curve of the accurate and reliable state of charge-open-circuit voltage can be obtained, the accurate open-circuit voltage can be obtained later, and the analysis accuracy of RC fitting parameters can be further improved.
In this alternative embodiment, optionally, the manner in which the second determining module 309 determines whether the correction operation needs to be performed on the state of charge-open circuit voltage fitted curve specifically includes:
calculating the coincidence degree of a fitting curve of the charge state-open circuit voltage and a fitting curve of the preset charge state-open circuit voltage of the battery core of the power battery, judging whether the coincidence degree is smaller than or equal to a preset coincidence degree threshold value, and determining that correction operation is required to be executed on the fitting curve of the charge state-open circuit voltage when the judgment result is negative; or alternatively, the process may be performed,
and calculating a second voltage difference between the fitting voltage and the observed voltage, judging whether the second voltage difference is smaller than or equal to a preset voltage difference value, and determining that correction operation is required to be executed on the fitting curve of the charge state-open circuit voltage when the judgment result is negative.
Therefore, the parameter fitting device based on the power battery RC fitting model described in fig. 4 can also determine that the fitting curve of the state of charge-open circuit voltage needs to be corrected, that is, the fitting curve of the state of charge-open circuit voltage needs to be re-fitted, when the coincidence degree of the fitting curve of the state of charge-open circuit voltage and the preset fitting curve is judged to be smaller or the obtained fitting voltage error is larger, so that the determination efficiency of the re-fitting of the fitting curve of the state of charge-open circuit voltage can be improved.
Example IV
Referring to fig. 5, fig. 5 is a schematic structural diagram of a parameter fitting device based on an RC fitting model of a power battery according to an embodiment of the invention. As shown in fig. 5, the apparatus may include:
a memory 401 storing executable program codes;
a processor 402 coupled with the memory 401;
further, an input interface 403 and an output interface 404 coupled to the processor 402 may also be included;
the processor 402 invokes executable program codes stored in the memory 401 to perform some or all of the steps in the parameter fitting method based on the power battery RC fitting model disclosed in the first or second embodiment of the present invention.
Example five
The embodiment of the invention discloses a computer storage medium which stores computer instructions for executing part or all of the steps in the parameter fitting method based on the RC fitting model of the power battery disclosed in the first embodiment or the second embodiment of the invention when the computer instructions are called.
The apparatus embodiments described above are merely illustrative, wherein the modules illustrated as separate components may or may not be physically separate, and the components shown as modules may or may not be physical, i.e., may be located in one place, or may be distributed over a plurality of network modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art will understand and implement the present invention without undue burden.
From the above detailed description of the embodiments, it will be apparent to those skilled in the art that the embodiments may be implemented by means of software plus necessary general hardware platforms, or of course by means of hardware. Based on such understanding, the foregoing technical solutions may be embodied essentially or in part in the form of a software product that may be stored in a computer-readable storage medium including Read-Only Memory (ROM), random-access Memory (Random Access Memory, RAM), programmable Read-Only Memory (Programmable Read-Only Memory, PROM), erasable programmable Read-Only Memory (Erasable Programmable Read Only Memory, EPROM), one-time programmable Read-Only Memory (OTPROM), electrically erasable programmable Read-Only Memory (EEPROM), compact disc Read-Only Memory (Compact Disc Read-Only Memory, CD-ROM) or other optical disc Memory, magnetic disc Memory, tape Memory, or any other medium that can be used for computer-readable carrying or storing data.
Finally, it should be noted that: the embodiment of the invention discloses a parameter fitting method and device based on a RC fitting model of a power battery, which are disclosed by the embodiment of the invention only for illustrating the technical scheme of the invention, but not limiting the technical scheme; although the invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art will understand that; the technical scheme recorded in the various embodiments can be modified or part of technical features in the technical scheme can be replaced equivalently; such modifications and substitutions do not depart from the spirit and scope of the corresponding technical solutions.

Claims (10)

1. A parameter fitting method based on a power battery RC fitting model, the method comprising:
acquiring current, observed voltage and target state of charge in a certain discharge time period in the discharging process of the power battery cell, and determining a resistance fitting parameter and a capacitance fitting parameter to be calculated of the power battery cell;
constructing an electrical parameter analysis function according to the resistance fitting parameter, the capacitance fitting parameter, the current, the discharge duration, the observed voltage and the target state of charge, and establishing an RC fitting model corresponding to the power battery cell based on the electrical parameter analysis function and a first-order Thevenin model;
And analyzing the resistance fitting parameter, the capacitance fitting parameter, the current, the discharge duration, the observed voltage and the target state of charge based on the established RC fitting model corresponding to the power battery cell to obtain the resistance fitting parameter and the capacitance fitting parameter of the power battery cell.
2. The method for fitting parameters based on an RC fitting model of a power battery according to claim 1, wherein the analyzing the resistance fitting parameter, the capacitance fitting parameter, the current, the discharge duration, the observed voltage, and the target state of charge based on the established RC fitting model corresponding to the power battery cell, to obtain the resistance fitting parameter and the capacitance fitting parameter of the power battery cell includes:
calculating a target open-circuit voltage of the target state of charge according to the determined fitting curve of the state of charge-open-circuit voltage, and calculating a first voltage difference between the target open-circuit voltage and the observed voltage;
and respectively setting corresponding initial estimated values for the resistance fitting parameters and the capacitance fitting parameters, and analyzing the resistance fitting parameters with the initial estimated values, the capacitance fitting parameters with the initial estimated values, the current and the first voltage difference based on the established RC fitting model corresponding to the power battery cell to obtain the resistance fitting parameters and the capacitance fitting parameters of the power battery cell.
3. The parameter fitting method based on a power cell RC fitting model of claim 1 or 2, wherein the method further comprises:
a plurality of first charge states of the power battery cell and open-circuit voltages corresponding to the first charge states are acquired at intervals, and each first charge state is acquired by standing for a preset period of time after the power battery cell stops discharging at the time;
and fitting each first charge state and the open-circuit voltage corresponding to the first charge state to obtain a fit curve of the charge state-open-circuit voltage of the power battery cell.
4. The method for fitting parameters based on an RC fitting model of a power battery according to claim 1 or 2, wherein after analyzing the resistance fitting parameter, the capacitance fitting parameter, the current, the discharge duration, the observed voltage, and the target state of charge based on the established RC fitting model corresponding to the power battery cell, the method further comprises:
and inputting the resistance fitting parameters and the capacitance fitting parameters into the first-order Thevenin model and the RC fitting model for analysis, and obtaining analysis results output by the first-order Thevenin model and the RC fitting model as fitting voltages of the power battery cells, wherein the fitting voltages of the power battery cells are used for evaluating fitting conditions of the fitting curve of the state-of-charge-open-circuit voltage and/or evaluating fitting conditions of the resistance fitting parameters and the capacitance fitting parameters.
5. The power cell RC fitting model-based parameter fitting method of claim 4, further comprising:
calculating a second voltage difference between the fitting voltage and the observed voltage, and judging whether the second voltage difference is smaller than or equal to a preset voltage difference value;
and when the judgment result is yes, updating the calculated resistance fitting parameter and the calculated voltage fitting parameter to respectively set corresponding initial estimated values for the resistance fitting parameter and the capacitance fitting parameter, and re-executing the operations of analyzing the resistance fitting parameter, the capacitance fitting parameter, the current and the first voltage difference with the initial estimated values set on the basis of the established RC fitting model corresponding to the power battery cell to obtain the resistance fitting parameter and the capacitance fitting parameter of the power battery cell.
6. The method of parameter fitting based on a power cell RC fitting model of any of claims 2-5, further comprising:
judging whether a correction operation is required to be executed on the fitting curve of the state of charge-open circuit voltage, and when the judgment result is yes, monitoring the electric quantity stationary phase of the power battery cell, and collecting a plurality of second states of charge in the electric quantity stationary phase and open circuit voltages corresponding to each second state of charge;
And fitting each second charge state and the open-circuit voltage corresponding to the second charge state to obtain a charge state-open-circuit voltage fitting curve of the power battery cell, wherein the charge state-open-circuit voltage fitting curve is used as a required charge state-open-circuit voltage fitting curve.
7. The method of claim 6, wherein the determining whether a correction operation is required for the state-of-charge-open-circuit voltage fitted curve comprises:
calculating the coincidence degree of the fitting curve of the charge state-open circuit voltage and the fitting curve of the preset charge state-open circuit voltage of the battery core of the power battery, judging whether the coincidence degree is smaller than or equal to a preset coincidence degree threshold value, and determining that correction operation is required to be executed on the fitting curve of the charge state-open circuit voltage when the judgment result is negative; or alternatively, the process may be performed,
and calculating a second voltage difference between the fitting voltage and the observed voltage, judging whether the second voltage difference is smaller than or equal to a preset voltage difference value, and determining that correction operation is required to be executed on the fitting curve of the charge state-open circuit voltage when the judgment result is negative.
8. A parameter fitting device based on a power cell RC fitting model, the device comprising:
The acquisition module is used for acquiring current, observed voltage and target state of charge in a certain discharge time period in the discharging process of the battery cell of the power battery;
the determining module is used for determining a resistance fitting parameter and a capacitance fitting parameter which need to be calculated for the power battery cell;
the establishing module is used for establishing an electric parameter analysis function according to the resistance fitting parameter, the capacitance fitting parameter, the current, the discharge duration, the observed voltage and the target state of charge, and establishing an RC fitting model corresponding to the power battery cell based on the electric parameter analysis function and a first-order Thevenin model which is determined in advance;
and the analysis module is used for analyzing the resistance fitting parameter, the capacitance fitting parameter, the current, the discharge duration, the observed voltage and the target state of charge based on the established RC fitting model corresponding to the power battery cell to obtain the resistance fitting parameter and the capacitance fitting parameter of the power battery cell.
9. A parameter fitting device based on a power cell RC fitting model, the device comprising:
a memory storing executable program code;
A processor coupled to the memory;
the processor invokes the executable program code stored in the memory to perform the parameter fitting method based on the power cell RC fitting model as claimed in any one of claims 1-7.
10. A computer storage medium storing computer instructions which, when invoked, perform the power cell RC fitting model-based parameter fitting method of any one of claims 1-7.
CN202211735308.1A 2022-12-30 2022-12-30 Parameter fitting method and device based on RC fitting model of power battery Pending CN116068405A (en)

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