CN113702845B - Retired lithium battery core parameter evaluation method and equipment - Google Patents
Retired lithium battery core parameter evaluation method and equipment Download PDFInfo
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- CN113702845B CN113702845B CN202111028132.1A CN202111028132A CN113702845B CN 113702845 B CN113702845 B CN 113702845B CN 202111028132 A CN202111028132 A CN 202111028132A CN 113702845 B CN113702845 B CN 113702845B
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- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 101
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 100
- 238000011156 evaluation Methods 0.000 title claims abstract description 20
- 238000000034 method Methods 0.000 claims abstract description 39
- 238000004088 simulation Methods 0.000 claims abstract description 34
- 238000012360 testing method Methods 0.000 claims abstract description 25
- 239000000463 material Substances 0.000 claims abstract description 19
- 230000006870 function Effects 0.000 claims description 35
- 239000003792 electrolyte Substances 0.000 claims description 33
- 239000007790 solid phase Substances 0.000 claims description 24
- 229910001416 lithium ion Inorganic materials 0.000 claims description 22
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims description 21
- 238000006243 chemical reaction Methods 0.000 claims description 21
- 238000009792 diffusion process Methods 0.000 claims description 19
- 238000012546 transfer Methods 0.000 claims description 18
- 239000012528 membrane Substances 0.000 claims description 16
- 239000002245 particle Substances 0.000 claims description 15
- 239000007774 positive electrode material Substances 0.000 claims description 11
- 239000000843 powder Substances 0.000 claims description 10
- 230000008569 process Effects 0.000 claims description 10
- 238000003411 electrode reaction Methods 0.000 claims description 8
- 239000006183 anode active material Substances 0.000 claims description 6
- 230000008859 change Effects 0.000 claims description 6
- 238000012937 correction Methods 0.000 claims description 5
- 150000002500 ions Chemical class 0.000 claims description 4
- 239000000758 substrate Substances 0.000 claims 1
- 230000008901 benefit Effects 0.000 abstract description 5
- 238000010586 diagram Methods 0.000 description 10
- 238000004891 communication Methods 0.000 description 5
- 238000007599 discharging Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000007773 negative electrode material Substances 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- 230000004044 response Effects 0.000 description 4
- 230000008878 coupling Effects 0.000 description 3
- 238000010168 coupling process Methods 0.000 description 3
- 238000005859 coupling reaction Methods 0.000 description 3
- 230000005012 migration Effects 0.000 description 3
- 238000013508 migration Methods 0.000 description 3
- 230000002093 peripheral effect Effects 0.000 description 3
- 230000032683 aging Effects 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000003062 neural network model Methods 0.000 description 2
- 230000000644 propagated effect Effects 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 238000004590 computer program Methods 0.000 description 1
- 238000003487 electrochemical reaction Methods 0.000 description 1
- 239000002001 electrolyte material Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 150000002641 lithium Chemical class 0.000 description 1
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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]
- G01R31/382—Arrangements for monitoring battery or accumulator variables, e.g. SoC
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Abstract
The invention relates to the field of lithium batteries, in particular to a retired lithium battery core parameter evaluation method and equipment. The method comprises the following steps: obtaining initial model parameters of a reference battery, wherein the reference battery and a retired lithium battery have the same material system; establishing an initial electrochemical model based on the initial model parameters; obtaining constant current discharge voltage curve data of the retired lithium battery for constant current discharge test and variable current discharge voltage curve data of the retired lithium battery for variable current discharge test; and adjusting model parameters of the initial electrochemical model based on the constant current discharge voltage curve data and the variable current discharge voltage curve data to obtain a target electrochemical model, wherein the target electrochemical model is used for evaluating core parameters of the retired lithium battery. The retired lithium battery core parameter evaluation method provided by the embodiment of the invention has the advantages of high compatibility, less required measured data and high simulation accuracy.
Description
[ Field of technology ]
The invention relates to the field of lithium batteries, in particular to a retired lithium battery core parameter evaluation method and equipment.
[ Background Art ]
The number of retired lithium batteries in China is increased year by year, and it is estimated that 80 ten thousand tons of retired lithium batteries are generated in China by 2025. Under the condition, according to the core parameters of the retired lithium battery, the retired lithium battery is utilized in a gradient manner, so that the problems of resource waste and environmental pollution can be avoided. Core parameters include, but are not limited to, state of Charge (SOC), power State of Power (SOP), and the like.
With the increase of the service time of the battery, the core parameters of the battery are changed continuously. Traditional function models, equivalent circuit models and neural network models have difficulty in accurately evaluating core parameters of a battery after aging, and model parameter calibration needs to be performed based on a large amount of measured data. Meanwhile, the model has poor compatibility, and core parameter evaluation cannot be performed on batteries produced by different factories under the same material system.
[ Invention ]
Therefore, the embodiment of the invention provides a retired lithium battery core parameter evaluation method and equipment, which can evaluate core parameters of batteries produced by different factories under the same material system and have the advantages of strong compatibility, less required actual measurement data and high simulation accuracy.
In a first aspect, an embodiment of the present invention provides a method for evaluating core parameters of a retired lithium battery, including:
Obtaining initial model parameters of a reference battery, wherein the reference battery and a retired lithium battery have the same material system;
Establishing an initial electrochemical model based on the initial model parameters;
obtaining constant current discharge voltage curve data of the retired lithium battery for constant current discharge test and variable current discharge voltage curve data of the retired lithium battery for variable current discharge test;
And adjusting model parameters of the initial electrochemical model based on the constant current discharge voltage curve data and the variable current discharge voltage curve data to obtain a target electrochemical model, wherein the target electrochemical model is used for evaluating core parameters of the retired lithium battery.
In one possible implementation manner, the initial model parameters include: positive electrode parameters, negative electrode parameters, battery reaction parameters, electrolyte parameters and diaphragm parameters; the establishing of the initial electrochemical model comprises the following steps:
Determining a positive electrode solid-phase charge state transfer function according to the positive electrode parameter and the battery reaction parameter;
determining a negative electrode solid-phase charge state transfer function according to the negative electrode parameter and the battery reaction parameter;
and determining a battery terminal voltage transfer function according to the anode parameter, the cathode parameter, the electrolyte parameter, the diaphragm parameter and the battery reaction parameter.
In one of the possible implementations of this method,
The positive electrode parameters include: one or more of a positive electrode active material particle size correlation coefficient, a positive electrode active material volume fraction, a positive electrode solid-phase lithium ion diffusion coefficient, a positive electrode maximum lithium concentration, a positive electrode powder thickness, a positive electrode porosity, a positive electrode regulation coefficient positive electrode equilibrium electromotive force differential function and a positive electrode reaction rate kinetic coefficient;
The negative electrode parameters include: one or more of a particle size correlation coefficient of the anode active material, a volume fraction of the anode active material, an anode solid-phase lithium ion diffusion coefficient, an anode maximum lithium concentration, an anode powder thickness, an anode porosity, an anode adjustment coefficient, an anode balance electromotive force differential function and an anode reaction rate kinetic coefficient;
The electrolyte parameters include: one or more of electrolyte ionic conductivity, electrolyte concentration, electrolyte lithium ion diffusion coefficient, and electrolyte ion particle transport number;
The diaphragm parameters include: one or more of membrane porosity, membrane turndown coefficient, and membrane thickness;
the battery reaction parameters include: one or more of membrane resistance, electrode reaction area, gas constant, and faraday constant.
In one possible implementation manner, obtaining a constant current discharge voltage curve of the retired lithium battery for constant current discharge test includes:
Constant-current discharging is carried out on the retired lithium battery in a full-charge state to a full-discharge state by adopting at least three groups of constant currents with different current values, and the constant-current discharging voltage curve data is determined according to a curve of the discharging voltage changing along with time in the constant-current discharging process
In one possible implementation manner, obtaining variable current discharge voltage curve data of the retired lithium battery for performing variable current discharge test includes:
And carrying out variable-current discharge on the retired lithium battery in the full-charge state to the full-discharge state, and determining the variable-current discharge voltage curve data according to a curve of discharge voltage change along with time in the variable-current discharge process.
In one possible implementation manner, adjusting the model parameters of the initial electrochemical model based on the variable current discharge voltage curve data includes:
Carrying out variable-flow discharge simulation on the initial electrochemical model to obtain first simulation data;
Obtaining a first model parameter value when the difference value between the first simulation data and the variable current discharge voltage curve data is minimum by using a least square method;
and correcting the model parameters of the initial electrochemical model according to the first model parameter values.
In one possible implementation manner, after adjusting the model parameters of the initial electrochemical model based on the variable current discharge voltage curve data, the method further includes:
performing constant-current discharge simulation on the initial electrochemical model to obtain second simulation data;
Obtaining a second model parameter value when the difference value between the second simulation data and the constant current discharge voltage curve data is minimum;
and correcting the model parameters of the initial electrochemical model according to the second model parameter values.
In a second aspect, an embodiment of the present invention provides a core parameter evaluation device for a retired lithium battery, including:
The acquisition module is used for acquiring initial model parameters of a reference battery, wherein the reference battery and the retired lithium battery have the same material system;
the modeling module is used for establishing an initial electrochemical model based on the initial model parameters
The acquisition module is also used for acquiring constant current discharge voltage curve data of the retired lithium battery for constant current discharge test and variable current discharge voltage curve data of the retired lithium battery for variable current discharge test;
The correction module is used for adjusting the model parameters of the initial electrochemical model based on the constant current discharge voltage curve data and the variable current discharge voltage curve data to obtain a target electrochemical model, and the target electrochemical model is used for evaluating the core parameters of the retired lithium battery.
In a third aspect, an embodiment of the present invention provides an electronic device, including:
at least one processor; and
At least one memory communicatively coupled to the processor, wherein:
the memory stores program instructions executable by the processor, the processor invoking the program instructions capable of performing the method provided in the first aspect.
In a fourth aspect, an embodiment of the present invention provides a computer readable storage medium, where the computer readable storage medium includes a stored program, where when the program runs, the program controls a device in which the computer readable storage medium is located to execute the method described in the first aspect.
It should be understood that, the second to fourth aspects of the embodiments of the present invention are consistent with the technical solutions of the first aspect of the embodiments of the present invention, and the beneficial effects obtained by each aspect and the corresponding possible implementation manner are similar, and are not repeated.
The method and the equipment for evaluating the core parameters of the retired lithium battery provided by the embodiment of the invention can evaluate the core parameters of batteries produced by different factories under the same material system, and have the advantages of strong compatibility, less required measured data and high simulation accuracy.
[ Description of the drawings ]
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flowchart of a method for evaluating core parameters of a retired lithium battery according to an embodiment of the present invention;
Fig. 2 is an effect schematic diagram of a single structure of a lithium battery according to an embodiment of the present invention;
FIG. 3 is a schematic diagram showing the effect of constant current discharge voltage curve data according to an embodiment of the present invention;
FIG. 4 is a schematic diagram showing the effect of the variable current discharge voltage curve data according to the embodiment of the present invention;
fig. 5 is a schematic diagram of a core parameter evaluation device for retired lithium battery according to an embodiment of the present invention;
Fig. 6 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.
[ Detailed description ] of the invention
For a better understanding of the technical solution of the present invention, the following detailed description of the embodiments of the present invention refers to the accompanying drawings.
It should be understood that the described embodiments are merely some, but not all, embodiments of the invention. 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 terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
Traditional function models, equivalent circuit models and neural network models have difficulty in accurately evaluating core parameters of a battery after aging, and model parameter calibration needs to be performed based on a large amount of measured data. Meanwhile, the model has poor compatibility, and core parameter evaluation cannot be performed on batteries produced by different factories under the same material system. The method and the equipment for evaluating the core parameters of the retired lithium battery provided by the embodiment of the invention can evaluate the core parameters of batteries produced by different factories under the same material system, and have the advantages of strong compatibility, less required measured data and high simulation accuracy.
Fig. 1 is a flowchart of a method for evaluating core parameters of a retired lithium battery according to an embodiment of the present invention. As shown in fig. 1, the above-mentioned retired lithium battery core parameter evaluation method may include:
step 101, obtaining initial model parameters of a reference battery, wherein the reference battery and the retired lithium battery have the same material system.
The retired lithium battery is an object of the embodiment of the invention, which needs core parameter evaluation. Selecting a reference battery with the same material system as the retired lithium battery, acquiring positive electrode parameters, negative electrode parameters, battery reaction parameters, electrolyte parameters and diaphragm parameters of the reference battery in an off-line calculation or literature searching mode, and taking the acquired parameters as initial model parameters.
The lithium battery is mainly composed of a positive electrode, a negative electrode, an electrolyte and a separator. The reference battery and the retired lithium battery have the same material system, and the reference battery and the retired lithium battery can be understood to have the same positive electrode material, negative electrode material, electrolyte material and diaphragm material.
Fig. 2 is a simplified schematic diagram of a lithium battery cell structure showing the anode, cathode and separator of the lithium battery. Wherein the battery cathode is an anode and consists of a plurality of anode particles; the positive electrode of the battery is a cathode and consists of a plurality of cathode particles. In the figure, C n represents the negative electrode lithium concentration, C p represents the positive electrode lithium concentration, and C e represents the electrolyte concentration; l n represents the negative electrode powder thickness, L p represents the positive electrode powder thickness, and L s represents the separator thickness. During the charging process of the lithium battery, lithium ions Li+ can be separated from the positive electrode and reach the negative electrode through the electrolyte and the diaphragm.
In this step, the initial model parameters to be acquired include: positive electrode parameters, negative electrode parameters, battery reaction parameters, electrolyte parameters, and separator parameters.
Wherein, the positive electrode parameter includes: the positive electrode active material particle size correlation coefficient, the positive electrode active material volume fraction, the positive electrode solid-phase lithium ion diffusion coefficient, the positive electrode maximum lithium concentration, the positive electrode powder thickness, the positive electrode porosity, the positive electrode regulating coefficient positive electrode balance electromotive force differential function and the positive electrode reaction rate kinetic coefficient;
Negative electrode parameters, including: the method comprises the steps of a particle size correlation coefficient of a negative electrode active material, a volume fraction of the negative electrode active material, a negative electrode solid-phase lithium ion diffusion coefficient, a negative electrode maximum lithium concentration, a negative electrode powder thickness, a negative electrode porosity, a negative electrode regulation coefficient, a negative electrode balance electromotive force differential function and a negative electrode reaction rate kinetic coefficient;
the electrolyte parameters include: electrolyte ionic conductivity, electrolyte concentration, electrolyte lithium ion diffusion coefficient and electrolyte ionic particle migration number;
A diaphragm parameter, comprising: one or more of membrane porosity, membrane turndown coefficient, and membrane thickness;
battery reaction parameters, including: membrane resistance, electrode reaction area, gas constant, and faraday constant.
After the initial model parameters are obtained, step 102 is continued.
Step 102, based on the initial model parameters, an initial electrochemical model is established.
And (3) taking the initial model parameters obtained in the step (101) as input parameters, and establishing an initial electrochemical model.
It should be noted that the electrochemical model adopts a series of partial differential equations and algebraic equation sets to accurately describe physical and chemical phenomena such as diffusion and migration of lithium ions in the battery, electrochemical reaction of the surfaces of active particles, and the like. The model not only can accurately simulate the external characteristics of the battery, but also can simulate the internal characteristic changes of the battery (such as the concentration of lithium ions in an electrode and electrolyte, the reaction overpotential and other internal physical quantities of the battery which are difficult to be actually measured). Compared with other battery models including an equivalent circuit model, the electrochemical model can deeply describe microscopic reactions inside the power battery and has a more definite physical meaning.
The electrochemical model established by the embodiment of the invention mainly simulates the internal characteristics and the external characteristics of the lithium battery by means of the positive solid phase charge state transfer function, the negative solid phase charge state transfer function and the battery terminal voltage transfer function.
Specifically, the positive solid phase state of charge transfer function is:
Wherein θ p represents the positive electrode solid phase charge state, β p represents the positive electrode active material particle size correlation coefficient, S represents the complex variable of the transfer function, D sp represents the positive electrode solid phase lithium ion diffusion coefficient, ε p represents the positive electrode active material volume fraction, F represents the faraday constant, and C p max represents the positive electrode maximum lithium concentration.
The negative solid phase state of charge transfer function is:
Wherein θ n represents the anode solid phase state of charge, β n represents the anode active material particle size correlation coefficient, S represents the complex variable of the transfer function, D sn represents the anode solid phase lithium ion diffusion coefficient, ε n represents the anode active material volume fraction, F represents the faraday constant, and C n max represents the anode maximum lithium concentration.
The battery terminal voltage transfer function is:
Wherein U (T) represents a function of a change in battery terminal voltage over time, I (T) represents a function of a change in battery terminal current over time, F p(θp) represents a positive equilibrium electromotive force differential function, L p represents a positive electrode powder thickness, a represents an electrode reaction area, F n(θn) represents a negative electrode equilibrium electromotive force differential function, L n represents a negative electrode powder thickness, L s represents a membrane thickness, k e represents an electrolyte ion conductivity, epsilon es represents a membrane porosity, bgls represents a membrane adjustment coefficient, R f represents a membrane resistance, R represents a gas constant, T ran + represents an electrolyte ion migration number, C e represents an electrolyte concentration, F represents a faraday constant, epsilon ep represents a positive electrode porosity, T represents a temperature, S represents a complex variable of a transfer function, D e represents an electrolyte lithium ion diffusion coefficient, bglp represents a positive electrode adjustment coefficient, epsilon n represents a negative electrode active material volume fraction, bgln represents a negative electrode adjustment coefficient, beta p represents a positive active material particle size correlation coefficient, epsilon p represents a positive electrode active material volume fraction, k p represents a positive electrode kinetic coefficient, C4332 represents a maximum lithium concentration, and C4332 represents a positive electrode concentration.
After the initial electrochemical model is established, step 103 is continued.
And step 103, obtaining constant current discharge voltage curve data of the retired lithium battery for constant current discharge test and variable current discharge voltage curve data of the retired lithium battery for variable current discharge test.
Specifically, at least three groups of constant currents with different multiplying powers are adopted to perform constant-current discharge on the retired lithium battery in a full-charge state to a full-discharge state, and constant-current discharge voltage curve data are determined according to a curve of discharge voltage change along with time in a constant-current discharge process.
Where the rate is a measure that can represent the rate of discharge, rate = discharge current/rated capacity. For example, when the battery 20A having a rated capacity of 100a·h is discharged, the discharge rate is 0.2C. In the embodiment of the invention, at least three groups of constant currents with different multiplying powers are adopted, namely at least three groups of constant currents with different current values are taken as discharge currents, at least 3 constant current discharge tests are carried out on the retired lithium battery, the retired lithium battery is discharged from 100% SOC to 0% SOC, a curve of discharge voltage changing along with time in each constant current discharge test is recorded, and the curve is taken as constant current discharge voltage curve data.
FIG. 3 is a schematic diagram of constant current discharge voltage curve data. As shown in fig. 3, the constant current discharge voltage curve data includes curves of discharge voltage of the retired lithium battery with time at 4 sets of constant currents with different multiplying powers.
In addition, in this step, it is also necessary to perform a variable current discharge test on the retired lithium battery to discharge the retired lithium battery from 100% soc to 0% soc, record a curve of a discharge voltage over time in the variable current discharge test, and use the curve as a variable current discharge voltage curve data. Fig. 4 is a schematic diagram of a variable current discharge voltage curve according to an embodiment of the present invention.
And 104, adjusting model parameters of the initial electrochemical model based on the constant current discharge voltage curve data and the variable current discharge voltage curve data to obtain a target electrochemical model, wherein the target electrochemical model is used for evaluating core parameters of the retired lithium battery.
In this step, the adjustment of the model parameters may be divided into two times, each time, different model parameters are adjusted. The first model parameters are adjusted for the first time, and the second model parameters are adjusted for the second time. Wherein the first model parameters include: positive electrode solid-phase lithium ion diffusion coefficient, positive electrode porosity, negative electrode solid-phase lithium ion diffusion coefficient, negative electrode porosity and electrolyte lithium ion diffusion coefficient; the second model parameters include: positive solid phase lithium ion diffusion coefficient, positive porosity, negative solid phase lithium ion diffusion coefficient, negative porosity and electrolyte lithium ion diffusion coefficient.
Specifically, during the first adjustment, the initial electrochemical model may be used to perform variable discharge simulation, so as to obtain first simulation data. The first simulation data are curves of discharge voltage changing along with time when the initial electrochemical model discharges from 100% SOC to 0% SOC under the changing current in the variable discharge simulation process. And then, calculating a first model parameter when the difference value between the first simulation data and the variable current discharge voltage curve data is minimum by using a least square method, and further correcting the first model parameter.
And reserving the parameter value of the first model after the first adjustment, and performing constant current discharge simulation by using the initial electrochemical model during the second adjustment to obtain second simulation data. Specifically, when constant current discharge test is performed on the retired lithium battery in step 103, constant current discharge simulation is performed on the initial electrochemical model by adopting constant current with the same group number and the same multiplying power, curves of discharge voltage changing along with time from 100% SOC to 0% SOC under each group of constant current are recorded respectively, and the curves are used as second simulation data. And then, according to the manual experience, the size of the second model parameter is adjusted, so that the difference value between the second simulation data and the constant current discharge voltage curve data reaches the minimum value as much as possible, and the correction of the second model parameter is further realized.
And correcting the model parameters of the initial electrochemical model twice to obtain the target electrochemical model. Compared with the initial electrochemical model, the target electrochemical model can simulate the internal characteristics and the external characteristics of the retired lithium battery with higher accuracy, so that the core parameters of the retired lithium battery can be evaluated. In the step, the model parameters of the initial electrochemical model can be adjusted for multiple times according to actual needs so as to improve the simulation accuracy of the target electrochemical model.
The core parameter evaluation method for the retired lithium battery provided by the embodiment of the invention can evaluate the core parameters of batteries produced by different factories under the same material system. Specifically, when core parameters of batteries produced by different manufacturers under the same material system are evaluated, only constant current discharge tests and variable current discharge tests are required to be performed on different retired lithium batteries in step 103, and constant current discharge voltage curve data and variable current discharge voltage curve data corresponding to each retired lithium battery are obtained respectively. And then, respectively adjusting model parameters of an initial electrochemical model corresponding to each retired lithium battery according to the constant current discharge voltage curve data and the variable current discharge voltage curve data of each retired lithium battery to obtain a target electrochemical model corresponding to each retired lithium battery. The retired lithium battery core parameter evaluation method provided by the embodiment of the invention has the advantages of less quantity of actually measured data to be input and high simulation accuracy.
Fig. 5 is a schematic diagram of a retired lithium battery core parameter evaluation device according to an embodiment of the present invention. As shown in fig. 5, the upper retired lithium battery core parameter evaluation device may include:
the obtaining module 51 obtains initial model parameters of a reference battery, which has the same material system as the retired lithium battery.
The modeling module 52 is configured to build an initial electrochemical model based on the initial model parameters.
The obtaining module 51 is further configured to obtain constant current discharge voltage curve data of the retired lithium battery for performing a constant current discharge test, and variable current discharge voltage curve data of the retired lithium battery for performing a variable current discharge test.
The correction module 53 is configured to adjust model parameters of the initial electrochemical model based on the constant current discharge voltage curve data and the variable current discharge voltage curve data to obtain a target electrochemical model, where the target electrochemical model is used to evaluate core parameters of the retired lithium battery.
The correction module 53 is specifically configured to perform variable-flow discharge simulation on the initial electrochemical model to obtain first simulation data; obtaining a first model parameter value when the difference value between the first simulation data and the variable current discharge voltage curve data is minimum by using a least square method; correcting model parameters of the initial electrochemical model according to the first model parameter values; performing constant-current discharge simulation on the initial electrochemical model to obtain second simulation data; obtaining a second model parameter value when the difference value between the second simulation data and the constant current discharge voltage curve data is minimum; and correcting the model parameters of the initial electrochemical model according to the second model parameter values.
The retired lithium battery core parameter evaluation device provided in the embodiment shown in fig. 5 may be used to implement the technical scheme of the method embodiment shown in fig. 1 of the present invention, and the implementation principle and technical effects may be further described with reference to the related description in the method embodiment.
Fig. 6 is a schematic structural diagram of an electronic device according to an embodiment of the present invention. The electronic device shown in fig. 6 is only an example and should not be construed as limiting the functionality and scope of use of the embodiments of the present invention.
As shown in fig. 6, the electronic device may include at least one processor; and at least one memory communicatively coupled to the processor, wherein: the memory stores program instructions executable by the processor, and the processor invokes the program instructions to execute the retired lithium battery core parameter evaluation method according to the embodiment shown in fig. 1. The electronic device is in the form of a general purpose computing device. Components of an electronic device may include, but are not limited to: one or more processors 410, a communication interface 420, a memory 430, and a communication bus 440 that connects the various system components (including the memory 430 and the processing unit 410).
The communication bus 440 represents one or more of any of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, a processor, or a local bus using any of a variety of bus architectures. By way of example, and not limitation, such architectures include industry Standard architecture (Industry Standard Architecture; hereinafter ISA) bus, micro channel architecture (Micro Channel Architecture; hereinafter MAC) bus, enhanced ISA bus, video electronics standards Association (Video Electronics Standards Association; hereinafter VESA) local bus, and peripheral component interconnect (PERIPHERAL COMPONENT INTERCONNECTION; hereinafter PCI) bus.
Electronic devices typically include a variety of computer system readable media. Such media can be any available media that can be accessed by the electronic device and includes both volatile and nonvolatile media, removable and non-removable media.
Memory 430 may include computer system readable media in the form of volatile memory, such as random access memory (Random Access Memory; hereinafter: RAM) and/or cache memory. The electronic device may further include other removable/non-removable, volatile/nonvolatile computer system storage media. Memory 430 may include at least one program product having a set (e.g., at least one) of program modules configured to carry out the functions of the embodiments of the invention.
A program/utility having a set (at least one) of program modules may be stored in the memory 430, such program modules including, but not limited to, an operating system, one or more application programs, other program modules, and program data, each or some combination of which may include an implementation of a network environment. Program modules typically carry out the functions and/or methods of the embodiments described herein.
Processor 410 executes programs stored in memory 430 to perform various functional applications and data processing, such as implementing the retired lithium battery core parameter assessment method provided by the embodiment of the present invention shown in fig. 1.
The embodiment of the invention provides a computer readable storage medium, which comprises a stored program, wherein when the program runs, equipment where the computer readable storage medium is located is controlled to execute the retired lithium battery core parameter evaluation method provided by the embodiment shown in the figure 1.
The computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, either in baseband or as part of a carrier wave. Such a propagated data signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination of the foregoing. A computer readable signal medium may also be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.
Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.
Computer program code for carrying out operations of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, smalltalk, C ++ and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any kind of network, including a local area network (Local Area Network; hereinafter: LAN) or a wide area network (Wide Area Network; hereinafter: WAN), or may be connected to an external computer (for example, through the Internet using an Internet service provider).
The foregoing describes certain embodiments of the present invention. Other embodiments are within the scope of the following claims. In some cases, the actions or steps recited in the claims can be performed in a different order than in the embodiments and still achieve desirable results. In addition, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.
In the description of the present invention, a description of the terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In the present invention, the schematic representations of the above terms are not necessarily for the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the various embodiments or examples described herein, as well as the features of the various embodiments or examples, may be combined and combined by those skilled in the art without contradiction.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.
Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and additional implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order from that shown or discussed, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the embodiments of the present invention.
Depending on the context, the word "if" as used herein may be interpreted as "at … …" or "at … …" or "in response to a determination" or "in response to a detection". Similarly, the phrase "if determined" or "if detected (stated condition or event)" may be interpreted as "when determined" or "in response to determination" or "when detected (stated condition or event)" or "in response to detection (stated condition or event), depending on the context.
In the several embodiments provided by the present invention, it should be understood that the disclosed systems, devices, and methods may be implemented in other manners. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of the elements is merely a logical function division, and there may be additional divisions when actually implemented, e.g., multiple elements or components may be combined or integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.
In addition, each functional unit in the embodiments of the present invention may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in hardware plus software functional units.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather to enable any modification, equivalent replacement, improvement or the like to be made within the spirit and principles of the invention.
Claims (9)
1. The method for evaluating the core parameters of the retired lithium battery is characterized by comprising the following steps of:
obtaining initial model parameters of a reference battery, wherein the reference battery and a retired lithium battery have the same material system, and the initial model parameters comprise: positive electrode parameters, negative electrode parameters, battery reaction parameters, electrolyte parameters and diaphragm parameters;
Establishing an initial electrochemical model based on the initial model parameters;
obtaining constant current discharge voltage curve data of the retired lithium battery for constant current discharge test and variable current discharge voltage curve data of the retired lithium battery for variable current discharge test;
Based on the constant current discharge voltage curve data and the variable current discharge voltage curve data, adjusting model parameters of the initial electrochemical model to obtain a target electrochemical model, wherein the target electrochemical model is used for evaluating core parameters of the retired lithium battery;
The establishing an initial electrochemical model based on the initial model parameters comprises the following steps:
Determining a positive electrode solid-phase charge state transfer function according to the positive electrode parameter and the battery reaction parameter;
determining a negative electrode solid-phase charge state transfer function according to the negative electrode parameter and the battery reaction parameter;
and determining a battery terminal voltage transfer function according to the anode parameter, the cathode parameter, the electrolyte parameter, the diaphragm parameter and the battery reaction parameter.
2. The method of claim 1, wherein the step of determining the position of the substrate comprises,
The positive electrode parameters include: one or more of a positive electrode active material particle size correlation coefficient, a positive electrode active material volume fraction, a positive electrode solid phase lithium ion diffusion coefficient, a positive electrode maximum lithium concentration, a positive electrode powder thickness, a positive electrode porosity, a positive electrode adjustment coefficient, a positive electrode equilibrium electromotive force differential function and a positive electrode reaction rate kinetic coefficient;
The negative electrode parameters include: one or more of a particle size correlation coefficient of the anode active material, a volume fraction of the anode active material, an anode solid-phase lithium ion diffusion coefficient, an anode maximum lithium concentration, an anode powder thickness, an anode porosity, an anode adjustment coefficient, an anode balance electromotive force differential function and an anode reaction rate kinetic coefficient;
The electrolyte parameters include: one or more of electrolyte ionic conductivity, electrolyte concentration, electrolyte lithium ion diffusion coefficient, and electrolyte ion particle transport number;
The diaphragm parameters include: one or more of membrane porosity, membrane turndown coefficient, and membrane thickness;
the battery reaction parameters include: one or more of membrane resistance, electrode reaction area, gas constant, and faraday constant.
3. The method of claim 1, wherein obtaining constant current discharge voltage profile data for the retired lithium battery for constant current discharge testing comprises:
and adopting at least three groups of constant currents with different current values to perform constant-current discharge on the retired lithium battery in a full-charge state to a full-discharge state, and determining constant-current discharge voltage curve data according to a curve of discharge voltage change along with time in a constant-current discharge process.
4. The method of claim 1, wherein obtaining variable current discharge voltage curve data for the retired lithium battery for variable current discharge testing comprises:
And carrying out variable-current discharge on the retired lithium battery in the full-charge state to the full-discharge state, and determining the variable-current discharge voltage curve data according to a curve of discharge voltage change along with time in the variable-current discharge process.
5. The method of claim 2, wherein adjusting model parameters of the initial electrochemical model based on the varying current discharge voltage curve data comprises:
Carrying out variable-flow discharge simulation on the initial electrochemical model to obtain first simulation data;
Obtaining a first model parameter value when the difference value between the first simulation data and the variable current discharge voltage curve data is minimum by using a least square method;
and correcting the model parameters of the initial electrochemical model according to the first model parameter values.
6. The method of claim 5, further comprising, after adjusting model parameters of the initial electrochemical model based on the varying current discharge voltage curve data:
performing constant-current discharge simulation on the initial electrochemical model to obtain second simulation data;
Obtaining a second model parameter value when the difference value between the second simulation data and the constant current discharge voltage curve data is minimum;
and correcting the model parameters of the initial electrochemical model according to the second model parameter values.
7. A retired lithium battery core parameter evaluation device, comprising:
The acquisition module acquires initial model parameters of a reference battery, wherein the reference battery and the retired lithium battery have the same material system, and the initial model parameters comprise: positive electrode parameters, negative electrode parameters, battery reaction parameters, electrolyte parameters and diaphragm parameters;
The modeling module is used for establishing an initial electrochemical model based on the initial model parameters;
The acquisition module is also used for acquiring constant current discharge voltage curve data of the retired lithium battery for constant current discharge test and variable current discharge voltage curve data of the retired lithium battery for variable current discharge test;
the correction module is used for adjusting the model parameters of the initial electrochemical model based on the constant current discharge voltage curve data and the variable current discharge voltage curve data to obtain a target electrochemical model, and the target electrochemical model is used for evaluating the core parameters of the retired lithium battery;
The modeling module is specifically used for determining a positive electrode solid-phase charge state transfer function according to the positive electrode parameter and the battery reaction parameter; determining a negative electrode solid-phase charge state transfer function according to the negative electrode parameter and the battery reaction parameter; and determining a battery terminal voltage transfer function according to the anode parameter, the cathode parameter, the electrolyte parameter, the diaphragm parameter and the battery reaction parameter.
8. An electronic device, comprising:
at least one processor; and
At least one memory communicatively coupled to the processor, wherein:
The memory stores program instructions executable by the processor, the processor invoking the program instructions to perform the method of any of claims 1-6.
9. A computer readable storage medium, characterized in that the computer readable storage medium comprises a stored program, wherein the program when run controls a device in which the computer readable storage medium is located to perform the method according to any one of claims 1 to 6.
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| CN114371409B (en) * | 2022-03-07 | 2023-07-04 | 上海玫克生储能科技有限公司 | Training method of battery state prediction model, battery state prediction method and device |
| CN115081332B (en) * | 2022-06-30 | 2023-04-14 | 上海玫克生储能科技有限公司 | Working condition sensitivity analysis and data processing method and device for parameter identification |
| WO2024130552A1 (en) * | 2022-12-20 | 2024-06-27 | 宁德时代新能源科技股份有限公司 | Battery model construction method, simulation method and apparatus, device, and storage medium |
| CN116184230A (en) * | 2023-02-28 | 2023-05-30 | 东莞市冠达自动化设备有限公司 | Lithium battery testing method, device, equipment and storage medium |
| CN115995628B (en) * | 2023-03-23 | 2023-06-30 | 深圳市杰成镍钴新能源科技有限公司 | Recovery processing method and device for retired lithium ion battery |
| CN116716622B (en) * | 2023-08-07 | 2023-12-15 | 福建德尔科技股份有限公司 | Fluorine gas preparation method and system based on electrolysis conditions |
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