Method, device, storage medium and product for determining expansion displacement of battery

Abstract

The present application discloses a method, device, storage medium and product for determining the expansion displacement of a battery. The method provided by the present application does not require manual measurement of the expansion displacement of the battery from time to time. Multiple models are coupled with each other, and the output of one sub-model is used as the input of another sub-model. The maximum expansion displacement of the target battery is predicted based on the cyclic calculation, and no human intervention is required. When it is determined that the current capacity of the target battery meets the preset conditions, the above cyclic calculation is stopped in time. Compared with manual, the preset efficiency and accuracy of predicting the maximum expansion displacement of the target battery through model calculation will be greatly improved.

Description

Technical Field

[0001] The present disclosure generally relates to the field of lithium batteries, and specifically to a method, device, storage medium and product for determining expansion displacement of a battery. Background Art

[0002] Lithium-ion batteries are widely used in the field of new energy vehicles due to their excellent electrochemical properties, long cycle life, no memory effect during use, and strong adaptability to high and low temperatures.

[0003] During the cycle of lithium-ion batteries, lithium ions are constantly intercalated and deintercalated between electrodes. In addition, SEI film is generated at the negative electrode during the cycle, which causes the battery material to expand. The formation of SEI (solid electrolyte interface) film will significantly increase the thickness of the negative electrode, thereby squeezing the external module and increasing the risk of module damage. Therefore, finding the maximum expansion displacement of lithium-ion batteries during the cycle is particularly important for the design and optimization of module materials.

[0004] However, currently, the expansion displacement of lithium-ion batteries during the cycle process is mainly obtained by manual testing methods. This method requires a lot of time, manpower, material resources and financial resources, which greatly increases the research and development costs of lithium-ion batteries. Summary of the invention

[0005] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a method, device, storage medium and product for quickly predicting the expansion displacement of a battery during charging and discharging.

[0006] A first aspect provides a method for determining expansion displacement of a battery, comprising:

[0007] Obtaining the current temperature of the target battery, performing temperature parameter calculation based on the current temperature, the first model, the second model, and the fourth model to obtain initial temperature parameters; the temperature parameter calculation includes inputting the current temperature into the first model to calculate the power parameter and the lithium concentration parameter, and inputting the current temperature into the second model to calculate the current density of the target battery to obtain initial power parameters and initial current density parameters, and inputting the initial power parameters and initial current density parameters into the fourth model to calculate the temperature parameters to obtain initial temperature parameters;

[0008] Determine whether the current capacity of the target battery meets a preset condition;

[0009] If not, the current temperature is updated to the initial temperature parameter, and the power parameter calculation, lithium concentration parameter calculation, current density calculation and temperature parameter calculation are cyclically performed according to the initial temperature parameter, the first model, the second model and the fourth model until the capacity of the target battery meets the preset conditions;

[0010] The target lithium concentration parameter obtained by the first model when the capacity of the target battery meets the preset conditions, the target current density of the target battery obtained by the second model, and the target temperature parameter obtained by the fourth model are input into the third model to obtain the target expansion displacement of the target battery.

[0011] A second aspect provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the method provided in the first aspect when executing the computer program.

[0012] According to a third aspect, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the method provided in the first aspect is implemented.

[0013] According to a fourth aspect, a computer program product is provided, comprising a computer program, which implements the method provided in the first aspect when executed by a processor.

[0014] The present application provides a method, device, storage medium and product for determining the expansion displacement of a battery. Considering that the existing method mainly relies on manual testing to obtain the maximum expansion displacement of a lithium-ion battery during a charge and discharge cycle, it consumes a lot of time, manpower, material resources and financial resources, which greatly increases the research and development cost of lithium-ion batteries. The present application provides a method for determining the expansion displacement of a battery through a model, wherein a power parameter and a lithium concentration parameter of the battery during charging and discharging are calculated through a first model, and a current density of a target battery during charging and discharging is calculated through a second model. The temperature parameters of the target battery after each charge and discharge are obtained through the power parameter calculation results of the first model, the current density calculation results of the second model, and a fourth model. Finally, the lithium concentration parameters calculated by the first model, the current density parameters calculated by the second model, and the temperature parameters calculated by the fourth model are combined with the third model for calculation. Since the target battery needs to be charged and discharged multiple times during the process of predicting the maximum expansion displacement of the target battery, the temperature of the target battery will change, that is, the calculation process of the first model, the second model, and the fourth model is a cyclic calculation process. Until it is determined that the current capacity of the target battery meets the preset conditions, the cyclic calculation is stopped, and the prediction result of the maximum expansion displacement of the target battery is obtained based on the current output of the first model, the second model, and the fourth model as the input of the third model. The method provided in the present application does not require manual measurement of the expansion displacement of the battery from time to time. Multiple models are coupled to each other, and the output of one sub-model is used as the input of another sub-model. The maximum expansion displacement of the target battery is predicted based on the cyclic calculation, and no manual intervention is required. When it is determined that the current capacity of the target battery meets the preset conditions, the above-mentioned cyclic calculation is stopped in time. Compared with manual prediction of the maximum expansion displacement of the target battery through model calculation, the preset efficiency and accuracy will be greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0016] Figure 1 A flowchart of the steps of a method for determining expansion displacement of a battery provided in the present application;

[0017] Figure 2 A flowchart of another method for determining expansion displacement of a battery provided in the present application;

[0018] Figure 3 A flowchart of another method for determining expansion displacement of a battery provided in the present application;

[0019] Figure 4 A flowchart of another method for determining expansion displacement of a battery provided in the present application;

[0020] Figure 5 A flowchart of another method for determining expansion displacement of a battery provided in the present application;

[0021] Figure 6 A flowchart of another method for determining expansion displacement of a battery provided in the present application;

[0022] Figure 7 A flowchart of another method for determining expansion displacement of a battery provided in the present application;

[0023] Figure 8 A diagram showing the expansion displacement prediction results of a battery provided in this application;

[0024] Fig. 9 A diagram showing the expansion displacement prediction results of a battery provided in this application;

[0025] Fig.10 A structural block diagram of a computer device provided in this application. DETAILED DESCRIPTION

[0026] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It is also necessary to explain that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0027] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0028] Lithium-ion batteries are widely used in the field of new energy vehicles due to their excellent electrochemical properties, long cycle life, no memory effect during use, and strong adaptability to high and low temperatures.

[0029] During the cycle of lithium-ion batteries, lithium ions are constantly intercalated and deintercalated between electrodes. In addition, SEI film is generated at the negative electrode during the cycle, which causes the battery material to expand. The formation of SEI (solid electrolyte interface) film will significantly increase the thickness of the negative electrode, thereby squeezing the external module and increasing the risk of module damage. Therefore, finding the maximum expansion displacement of lithium-ion batteries during the cycle is particularly important for the design and optimization of module materials.

[0030] However, currently, the expansion displacement of lithium-ion batteries during the cycle is mainly obtained by manual testing, which requires a lot of time, manpower, material and financial resources, greatly increasing the research and development cost of lithium-ion batteries.

[0031] In view of the above problems, this application provides a new method for determining the expansion displacement of a battery, please refer to Figure 1 , the method comprises the following steps:

[0032] Step S20, obtaining the current temperature of the target battery, performing temperature parameter calculation based on the current temperature, the first model, the second model and the fourth model to obtain initial temperature parameters; the temperature parameter calculation includes inputting the current temperature into the first model to calculate the power parameter and the lithium concentration parameter and inputting the current temperature into the second model to calculate the current density of the target battery to obtain initial power parameters and initial current density parameters, and inputting the initial power parameters and the initial current density parameters into the fourth model to calculate the temperature parameters to obtain initial temperature parameters;

[0033] The target battery is any battery among the numerous batteries produced that needs to be currently predicted for the maximum expansion displacement.

[0034] The current temperature of the target battery can be determined by measuring the ambient temperature of the target battery when it leaves the factory; it can also be determined by measuring the ambient temperature of the target battery just before the maximum expansion displacement prediction of the target battery. The present application does not limit this. Using the actual ambient temperature of the target battery as the initial temperature for the cycle calculation can better simulate the target battery and obtain more accurate prediction results.

[0035] The first model is used to calculate the primary battery reaction parameters generated during the charge and discharge of the target battery; the primary battery reaction parameters refer to the parameters generated by the reactions that can occur in the target battery itself during the charge and discharge process, and these reactions will not affect the life of the battery. These reactions include, for example, intercalation and deintercalation reactions, solid phase charge conservation, liquid phase charge conservation, lithium ion diffusion inside the battery, lithium ion diffusion in the electrolyte, etc. Exemplarily, the primary battery parameters are, for example, the current density of lithium intercalation and deintercalation reactions, solid phase current density, liquid phase current density, lithium concentration in the solid phase, and liquid phase volume fraction.

[0036] So the first model can be described by the following five relationships:

[0037] The first relationship is used to describe the deintercalation reaction of the battery, and the first relationship is related to the current density of the deintercalation reaction, the anode transfer coefficient of the target battery, the cathode transfer coefficient of the target battery, the exchange current density of the deintercalation reaction, the Faraday constant, the gas constant, the overpotential of the deintercalation reaction, the temperature, the solid phase potential, the liquid phase potential, the equilibrium potential of the positive and negative electrodes of the target battery, and the potential drop;

[0038] For example, the expression of the first relation is:

[0039]

[0040] η=Φ s -Φ l -E Eq -U de

[0041] Among them, α a and α c are the transfer coefficients of the anode and cathode, respectively, j is the current density of the lithium deintercalation reaction, j0 is the exchange current density of the lithium deintercalation reaction (calculated using the reaction rate constant), F is the Faraday constant, R is the gas constant, η is the overpotential of the lithium deintercalation reaction, T is the temperature, Φ s is the solid phase potential, Φ l is the liquid phase potential, E Eq is the equilibrium potential of the positive and negative electrodes, U de is the potential drop caused by all side reactions. Since the loss in the positive electrode is not considered, there is no U in the positive electrode. de produce.

[0042] The second relationship is used to describe the solid phase diffusion of lithium ions inside the battery. The second relationship is related to the lithium concentration in the solid phase, the radius of the active particles, and the solid phase effective diffusion coefficient;

[0043] The expression of the second relational equation is, for example:

[0044]

[0045] Among them, c s is the lithium concentration in the solid phase, r is the radius of the active particle, D s is the solid phase effective diffusion coefficient (calculated using the Brugg parameter at the diaphragm and the diffusion activation energy). The positive and negative electrode equilibrium potentials in the first relationship are related to the lithium concentration in the solid phase in the second relationship.

[0046] The third relational expression is used to describe the solid phase charge conservation of the target battery during a charge and discharge process. The third relational expression is related to the solid phase current density, the solid phase effective conductivity and the solid phase potential;

[0047] The expression of the third relational equation is, for example:

[0048]

[0049] Among them, i s is the solid phase current density, σ s is the solid phase effective conductivity, Φ s is the solid phase potential.

[0050] The fourth relationship is used to describe the liquid phase charge conservation of the target battery during a charge and discharge process. The fourth relationship is related to the liquid phase current density, liquid phase effective conductivity, thermodynamic factor, lithium ion transport number, liquid phase concentration, Faraday constant, gas constant, temperature and liquid phase potential;

[0051] The expression of the fourth relational equation is, for example:

[0052]

[0053] Among them, i l is the liquid current density, κ is the liquid effective conductivity, is the thermodynamic factor, which is a constant. is the lithium ion transport number, c l is the liquid concentration, Φ l is the liquid phase potential, F is the Faraday constant, R is the gas constant, and T is the temperature.

[0054] The fifth relation is used to describe the diffusion of lithium ions in the electrolyte during a charge and discharge process of the target battery. The fifth relation is related to the liquid phase volume fraction, current density, liquid phase effective diffusion coefficient, lithium ion transport number, active particle specific surface area, liquid phase concentration and Faraday exposition.

[0055] The expression of the fifth relational equation is, for example:

[0056]

[0057] Among them, ε l is the liquid volume fraction (or electrolyte volume fraction), j is the current density, D l is the effective diffusion coefficient of the liquid phase (calculated using the Brugg parameter at the diaphragm and the diffusion activation energy), t + 0 is the lithium ion transport number, a s is the specific surface area of ​​active particles, c l is the liquid concentration, and F is the Faraday constant.

[0058] The second model is used to obtain the side reaction parameters of the battery. The side reaction parameters refer to the parameters generated by the reaction that shortens the life of the target battery during the charge and discharge process, such as the generation of a solid electrolyte interface film at the negative electrode of the battery, the precipitation of lithium ions in the battery, etc. Exemplarily, the side reaction parameters are, for example, the current density of the generation side reaction, the current density of the regeneration side reaction, and the current density of the lithium precipitation side reaction.

[0059] It should be noted here that, in order to improve the efficiency of prediction, the second model of the present application may be to only consider the side reaction of SEI generation. Then the second model may be related to the current density of the side reaction, the exchange current density of the side reaction, the transfer coefficient, the equilibrium potential, the potential drop, the Faraday constant, the gas constant, the temperature and the overpotential of the side reaction;

[0060] The second model can be expressed by the following expression:

[0061]

[0062] η SEI =Φ s -Φ l -E Eq,SEI -U de

[0063] Among them, j SEI The side reaction current density generated by the solid electrolyte interface film, j 0,SEI Generates the side reaction exchange current density for the solid electrolyte interface film, α c,SEI is the transfer coefficient, E Eq,SEI is the equilibrium potential of the solid electrolyte interface film, which can be assigned a value of 0.4 V, U de is the potential drop caused by all side reactions, η SEI is the overpotential for the side reaction, R is the gas constant, T is the temperature parameter, F is the Faraday constant, Φ s is the solid phase potential, Φ l is the liquid phase potential.

[0064] The fourth model is used to describe the heat generated by the battery during the charging and discharging process. The relationship equations of the fourth model include, for example:

[0065]

[0066] Where ρ is the density of the battery material, C p is the specific heat capacity of the battery material, λ is the thermal conductivity of the battery material, is the heat dissipation power, is the solid phase ohmic heat generation power and the liquid phase ohmic heat generation power, is the polarization heat generation power, is the reversible heat generation power ( is experimentally measured), a i Corresponding to the specific surface area of ​​the positive and negative active particles, i iIt is related to the current density of the lithium deintercalation reaction in the first relationship, the current density of the solid electrolyte interface film formation side reaction in the sixth relationship to be described later, the current density of the solid electrolyte interface film regeneration side reaction in the seventh relationship, and the current density of the lithium precipitation side reaction.

[0067] It should be noted here that the present application is described by taking the calculation of power parameters and lithium concentration after charging and discharging the target battery once as an example.

[0068] Based on the above description of the relationship between the first model, the second model and the fourth model, in order to perform operations according to the above relationship, it is also necessary to obtain the model parameters corresponding to each model. Since the model parameters corresponding to each model are known quantities, they are not described here.

[0069] The first model parameters of the first model include, for example, the transfer coefficients of the anode and cathode, the lithium ion concentration in the solid phase, the radius of the active particles, the solid phase potential, the lithium ion concentration in the liquid phase, etc. It should be noted that the first model parameters include both adjustable parameters and non-adjustable parameters.

[0070] The second model parameters of the second model include, for example, the equilibrium potential of the regeneration reaction, the initial film thickness, etc. The second model parameters include adjustable parameters and non-adjustable parameters.

[0071] The fourth model parameters of the fourth model include, for example, density of the battery material, specific heat capacity of the battery material, thermal conductivity of the battery material, etc. Similarly, the fourth model parameters also include adjustable parameters and non-adjustable parameters.

[0072] In another embodiment of the present application, Figure 2 As shown, Figure 2 The method includes the following steps:

[0073] Step S201, constructing a geometric model of the target battery according to the design parameters of the target battery, the geometric model being used to perform charge and discharge simulation on the target battery;

[0074] Among them, the geometric model of the target battery is used to simulate the target battery itself, so the physical parameters of the target battery are needed. These physical parameters include, for example, the thickness of the positive electrode of the target battery, the thickness of the negative electrode of the target battery, the thickness of the diaphragm of the target battery, the particle size of the positive electrode active material of the target battery, the particle size of the negative electrode active material of the target battery, the porosity of the target battery diaphragm, the solid phase volume fraction of the positive electrode of the target battery, the liquid phase volume fraction of the positive electrode of the target battery, the solid phase volume fraction of the negative electrode of the target battery, the liquid phase volume fraction of the negative electrode of the target battery, etc.

[0075] According to the physical parameters of the target battery itself, a geometric model of the target battery can be constructed, so that the actual charging and discharging process of the target battery can be simulated through computer equipment, and there is no need to continuously charge and discharge the target battery manually.

[0076] Since the target battery will generate some data such as primary battery reaction data, solid phase potential, liquid phase potential, solid phase concentration, liquid phase concentration, current density, battery temperature, etc. during the charge and discharge process, the above data will also be generated when the target battery is charged and discharged by computer equipment, which is called simulation parameters here.

[0077] Step S202, obtaining simulation parameters generated by the geometric model during the charge and discharge simulation of the target battery.

[0078] Among them, since the simulation parameters generated by the geometric model are closely related to the model parameters in each model, after each charge and discharge of the target battery, it is necessary to obtain the simulation parameters generated during the charge and discharge process so as to be used for the subsequent models to perform corresponding calculations.

[0079] That is to say, in the process of executing power parameter calculation and lithium concentration parameter calculation, the first model needs to input corresponding temperature parameters (such as current temperature), first model parameters and simulation parameters to the first model, so as to obtain corresponding power parameters and lithium concentration parameters. It should be noted here that when the first model participates in the cyclic calculation between the second model and the fourth model, the lithium concentration parameter calculation may not be performed, but when the cyclic calculation is stopped, the lithium concentration parameter needs to be output as the input of the third model.

[0080] Similarly, when the second model performs current density calculation, it is necessary to input corresponding temperature parameters (such as current temperature), second model parameters and simulation parameters into the second model, so as to obtain corresponding current density parameters.

[0081] It can be understood that when performing temperature parameter calculation through the fourth model, in addition to inputting the calculation results of the first model and the calculation results of the second model, it is also necessary to input the fourth model parameters and simulation parameters corresponding to the fourth model accordingly, so that the temperature parameters can be calculated to obtain the temperature parameters of the target battery after each charge and discharge is completed.

[0082] It should be noted here that the simulation parameters required by the first model, the second model and the fourth model may be the same or different.

[0083] In combination with the above exemplary descriptions of the relationship between the first model, the second model and the fourth model, how to calculate the power parameter, the lithium concentration parameter, the current density and the temperature parameter is described respectively. Figure 3 .

[0084] In one embodiment, Figure 3 As shown, an optional method embodiment of performing power parameter calculation and lithium concentration parameter calculation provided by the present application is provided, and the method embodiment comprises the following steps:

[0085] Step S301, inputting the current temperature into the first relational expression of the first model, the first relational expression outputs the lithium intercalation and deintercalation reaction current density, the overpotential of the lithium intercalation and deintercalation reaction, the solid phase potential and the liquid phase potential, the first relational expression is used to describe the intercalation and deintercalation reaction of the target battery during a charge and discharge process; the first relational expression is related to the positive and negative electrode equilibrium potentials of the target battery, the positive and negative electrode equilibrium potentials of the target battery are determined by the second relational expression in the first model, and the second relational expression is used to describe the diffusion of lithium ions inside the target battery during a charge and discharge process of the target battery;

[0086] Among them, power parameters include heat dissipation power, polarization heat generation power, reversible heat generation power, solid phase ohmic heat generation power, liquid phase ohmic heat generation power, etc. The lithium deintercalation reaction current density and the overpotential of the lithium deintercalation reaction output by the first relational expression can be used to perform polarization heat generation power and reversible heat generation power of the target battery in a single charge and discharge. This calculation process needs to rely on the fourth model.

[0087] The solid phase potential and the liquid phase potential are used to provide input for the calculation of the third and fourth relations.

[0088] In addition, the first relational expression and the positive and negative electrode equilibrium potentials of the target battery can be determined by the second relational expression. That is to say, the relational expressions in the first model are coupled with each other, and the output of one relational expression can be used as the input of another relational expression, so that cyclic calculations can be performed without manual intervention to obtain the parameters of each charge and discharge of the target battery.

[0089] Step S302, inputting the solid phase potential into the third relational expression of the first model to obtain the solid phase current density and the first lithium concentration parameter, wherein the third relational expression is used to describe the solid phase charge conservation of the target battery during a charge and discharge process;

[0090] Among them, the third relationship includes three parameters: solid phase current density, solid phase effective conductivity and solid phase potential. The solid phase potential can be obtained through the first relationship. The solid phase effective conductivity is a known parameter, so the solid phase current density can be calculated. The solid phase current density and solid phase potential can be combined with the fourth model to calculate the solid phase ohmic heat generation power.

[0091] Step S303, input the current temperature and liquid phase potential into the fourth relationship of the first model to obtain the liquid phase current density, the fourth relationship is used to describe the conservation of liquid phase charge of the target battery during a charge and discharge process, the fourth relationship is related to the liquid phase concentration of the target battery, the liquid phase concentration of the target battery is determined by the fifth relationship in the first model, and the fifth relationship is used to describe the diffusion of lithium ions in the electrolyte during a charge and discharge process of the target battery.

[0092] Among them, the current temperature is a measured value, which can be continuously updated through the output of the fourth model in subsequent cycle calculations, so as to obtain the power parameters, lithium concentration parameters and current density parameters of the target battery after each charge and discharge.

[0093] The liquid phase potential is obtained by the first relational expression, and the liquid phase concentration in the fourth relational expression can be calculated by the fifth relational expression. The liquid phase current density, liquid phase potential and the fourth model output by the fourth relational expression can be used to calculate the liquid phase ohmic heat generation power of the target battery in one charge and discharge.

[0094] It should be noted here that the power parameter calculation performed by the first model cannot directly obtain the power parameters, but obtains the parameters required for subsequent power calculations, which are called initial power parameters here, where the initial power parameters include the current density of lithium intercalation and delithiation reaction, the overpotential of lithium intercalation and delithiation reaction, solid phase current density, solid phase potential, liquid phase current density and liquid phase potential.

[0095] The present application uses the first model to calculate power parameters and lithium concentration parameters without actual measurement, and the first model can perform cyclic calculations when the temperature changes, with high calculation efficiency. The power parameters obtained can be used in the subsequent calculation of the target battery temperature parameters, and the lithium concentration parameters can be used in the subsequent prediction of the expansion displacement of the target battery.

[0096] In one embodiment, Figure 4 As shown, an optional method embodiment for calculating current density provided by the present application is provided, and the method embodiment comprises the following steps:

[0097] Step S401, determining the overpotential of the target battery for the side reaction according to the side reaction parameters, solid phase potential and liquid phase potential of the target battery;

[0098] Step S402, determining an initial current density parameter according to the overpotential, the Faraday constant, the transfer coefficient, the gas constant, the exchange current density of the target battery and the current temperature.

[0099] The side reaction parameters of the target battery include, for example, at least one of the exchange current density, the transfer coefficient, the equilibrium potential of the SEI, and the potential drop. The equilibrium potential of the SEI can usually be reset to 0.4V.

[0100] The solid phase potential and liquid phase potential are calculated by the first relationship in the first model. According to the following formula:

[0101] η SEI =Φ s -Φ l -E Eq,SEI -U de

[0102] The overpotential of the target battery side reaction can be calculated. The above symbols have been explained above and will not be repeated here.

[0103] Then, the initial current density parameters are calculated according to the following formula:

[0104]

[0105] Among them, j SEI This is the current density parameter that needs to be calculated.

[0106] As the target battery is continuously intercalated and deintercalated between electrodes during the charge and discharge cycle, and a SEI film is generated at the negative electrode of the target battery, the target battery material will expand. As the target battery is continuously charged and discharged, the target battery material will undergo a greater displacement due to expansion. However, the expansion displacement of the target battery is not infinite. As the target battery reaches its end of life after multiple charge and discharge cycles, the target battery will have a maximum expansion displacement.

[0107] During the continuous charging and discharging of the target battery, the maximum expansion displacement of the target battery is predicted, which can reduce the risk of the target battery damaging the peripheral modules.

[0108] In one embodiment, Figure 5 As shown, an optional method embodiment for calculating current density provided by the present application is provided, and the method embodiment comprises the following steps:

[0109] Step S501, inputting the lithium deintercalation reaction current density, the lithium deintercalation reaction overpotential, and the initial current density parameters into the fourth model to obtain polarization heat generation power and reversible heat generation power;

[0110] Step S502, inputting the solid phase current density and the solid phase potential into the fourth model to obtain the solid phase ohmic heat generation power;

[0111] Step S503, inputting the liquid phase current density and the liquid phase potential into the fourth model to obtain the liquid phase ohmic heat generation power;

[0112] Step S504, obtaining initial temperature parameters according to the polarization heat generation power, the reversible heat generation power, the solid phase ohmic heat generation power, the liquid phase ohmic heat generation power and the fourth model.

[0113] Among them, the current density of the lithium deintercalation reaction and the overpotential of the lithium deintercalation reaction can be calculated by the first model; the first current density parameter can be obtained by the second model; based on these three parameters, the two parameters of polarization heat generation power and reversible heat generation power can be calculated.

[0114] Similarly, the solid phase current density and solid phase potential can be calculated by the first model, and these two parameters can be input into the fourth model to obtain the solid phase ohmic heat generation power. The liquid phase current density and liquid phase potential can be calculated by the first model, and these two parameters can be input into the fourth model to obtain the liquid phase ohmic heat generation power.

[0115] By using the outputs of the first model and the second model as the inputs of the fourth model, the temperature parameters of the target battery after each charge and discharge can be obtained based on the output of the fourth model.

[0116] Several models can be coupled with each other to perform cyclic calculations without the need for human intervention throughout the process, which can improve prediction efficiency.

[0117] It is understandable that the first model, the second model and the fourth model can be constructed as an overall target model and stored in the memory address of the server, terminal device, etc. When the maximum expansion displacement of the target battery needs to be predicted, the model can be called from the corresponding memory address.

[0118] Step S30, determining whether the current capacity of the target battery meets a preset condition.

[0119] The current capacity of the target battery can be used to measure the life of the target battery, because when the current capacity of the target battery is less than a certain value, the target battery can no longer be used, and the maximum expansion displacement of the target battery can be obtained at this time. The preset condition can be determined based on historical measured data, historical record data, etc., and this application does not limit this. An exemplary preset condition is, for example, that the current capacity is less than or equal to 80%.

[0120] In an optional embodiment, if Figure 6 As shown, an optional method embodiment of determining whether the current capacity of a target battery meets a preset condition provided by the present application is provided. The method embodiment comprises the following steps:

[0121] Step S601, obtaining a constant current of a target battery during a charging and discharging process;

[0122] Step S602, obtaining the discharge time of the target battery during one charge and discharge process;

[0123] Step S603, integrating the constant current according to the discharge time to obtain the current capacity of the target battery after one charge and discharge;

[0124] Step S604, comparing the current capacity with the battery capacity after the last charge and discharge;

[0125] Step S605: If the ratio of the current capacity to the battery capacity is greater than a preset threshold, it is determined that the current capacity of the target battery does not meet a preset condition.

[0126] The current of the target battery is constant during the charging and discharging process, which can be obtained through simulation software or through the above relationship, and is not limited here.

[0127] After setting the cycle conditions, the discharge time of the target battery during each charge and discharge process can also be obtained through the constructed geometric model or simulation software.

[0128] Then calculate the current capacity of the target battery after one charge and discharge according to the following formula:

[0129] Q cell =∫I cell dt

[0130] Among them, Q cell is the battery capacity, I cell is the current, and t is the discharge time.

[0131] Since the target battery will produce side reactions after continuous charging and discharging, these side reactions will not only affect the life of the target battery, but also affect the charging and discharging time of the target battery. Therefore, the discharge time of the target battery will be different each time, so the battery capacity calculated will also have a tendency to gradually decrease, until it is determined that the ratio of the current capacity of the target battery to the battery capacity is less than the preset threshold, then it can be determined that the current capacity of the target battery meets the preset conditions. Then, as long as the ratio of the current capacity of the target battery to the battery capacity is greater than or equal to the preset threshold, it can be said that the target battery has not reached the maximum expansion displacement, so it is necessary to continue the cyclic calculation. Otherwise, stop the cyclic calculation and directly output the expansion displacement obtained by the last calculation as the maximum expansion displacement of the target battery.

[0132] Step S40, if not satisfied, the current temperature is updated to the initial temperature parameter, and the power parameter calculation, lithium concentration parameter calculation, current density calculation and temperature parameter calculation are cyclically performed according to the initial temperature parameter, the first model, the second model and the fourth model until the capacity of the target battery meets the preset conditions.

[0133] Among them, according to the above method, it is determined whether the current capacity of the target battery meets the preset conditions. When it is determined that the current capacity does not meet the preset conditions, that is, the current capacity of the target battery is still greater than or equal to 80%. At this time, the above cycle calculation needs to continue. Since the temperature of the target battery changes after each charge and discharge, the data that needs to be updated during the cycle calculation is the temperature of the target battery, and the temperature of the target battery after each charge and discharge is calculated by the fourth model. Therefore, as long as the current capacity of the target battery does not meet the preset conditions, the temperature parameter is calculated by the fourth model to obtain the initial temperature parameter of the target battery, and the current temperature is updated to the initial temperature parameter, and then the power parameter and lithium concentration parameter are calculated according to the first model, the current density of the target battery is calculated according to the second model, and the temperature parameter is calculated according to the fourth model, and a new temperature parameter is obtained. Then the initial temperature parameter is updated to the new temperature parameter, and the power parameter and lithium concentration parameter are calculated according to the first model, the current density of the target battery is calculated according to the second model, and the temperature parameter is calculated according to the fourth model, and a new temperature parameter is obtained, and so on.

[0134] It is understandable that the above cycle calculation has a cutoff condition, which is that the capacity of the target battery meets the preset condition. Then when the capacity of the target battery meets the preset condition, the first model, the second model and the fourth model will obtain power parameters, lithium concentration parameters, current density parameters and temperature parameters according to corresponding calculations.

[0135] Step S50, when the capacity of the target battery meets the preset conditions, the target lithium concentration parameter obtained by the first model, the target current density parameter of the target battery obtained by the second model, and the target temperature parameter obtained by the fourth model are input into the third model to obtain the target expansion displacement of the target battery.

[0136] The third model is used to calculate the expansion displacement of the target battery after each charge and discharge.

[0137] The third model can be described, for example, by the following expression:

[0138]

[0139] s total = l pos ε zz,pos +l sep ε zz,sep +l nep ε zz,nep

[0140] where ε ij is the strain component (including ε zz,pos , ε zz,sep , εzz,neg ), σ ij is the stress component, E is Young's modulus, ν is Poisson's ratio, ins(SOC) is the intercalation strain of the electrode material, SOC represents the lithium insertion state, which can be expressed by C s / C s,max Calculated, α T is the thermal expansion coefficient, T is the temperature parameter, inc(C loss / C s,max ) is the irreversible strain of the electrode material caused by the side reaction, C loss is the lithium concentration lost due to side reactions; C s,max is the maximum lithium insertion concentration of the negative electrode particles; δ ij is the Dirac function, which is 1 when i=j and 0 in other cases. total is the maximum expansion displacement, l pos is the initial thickness of the positive electrode, l sep is the initial thickness of the diaphragm, l nep is the initial thickness of the negative electrode. zz,pos is the maximum strain in the thickness direction of the positive electrode, ε zz,sep is the maximum strain in the thickness direction of the diaphragm, ε zz,neg is the maximum strain in the thickness direction of the negative electrode.

[0141] In this application, when the capacity of the target battery meets the preset conditions, the first model, the second model and the fourth model are obtained according to the corresponding calculations to obtain lithium concentration parameters, current density parameters and temperature parameters, which are referred to as target lithium concentration parameters, target current density parameters of the target battery and target temperature parameters. The above parameters are input into the third model.

[0142] It should be noted here that the target current density parameters, the specific surface area of ​​the active particles and the Faraday constant are based on The loss lithium concentration parameter is calculated by the formula. The specific surface area of ​​the active particles can be calculated by the fifth relationship of the first model mentioned above, which will not be described in detail here.

[0143] In an optional embodiment, if Figure 7 As shown, an optional method embodiment of obtaining the current expansion displacement of a target battery provided by the present application is provided, and the method embodiment comprises the following steps:

[0144] Step S701, inputting the target temperature parameter, the target lithium concentration parameter and the target current density parameter into the third model, obtaining the maximum strain of the target battery in the positive electrode thickness direction, the maximum strain of the target battery in the separator thickness direction and the maximum strain of the target battery in the negative electrode thickness;

[0145] Step S702, taking the product of the maximum strain of the target battery in the thickness direction of the positive electrode and the initial thickness of the positive electrode of the target battery as the first expansion displacement of the target battery in the thickness direction of the positive electrode;

[0146] Step S703, taking the product of the maximum strain of the target battery in the diaphragm thickness direction and the initial thickness of the target battery diaphragm as the second expansion displacement of the target battery in the diaphragm thickness direction;

[0147] Step S704, taking the product of the maximum strain of the target battery on the thickness of the negative electrode and the initial thickness of the negative electrode of the target battery as the third expansion displacement of the target battery in the thickness direction of the negative electrode;

[0148] Step S705: determining the sum of the first expansion displacement, the second expansion displacement and the third expansion displacement as the current expansion displacement of the target battery.

[0149] Among them, based on the above description of the third model expression, the target temperature parameter, the target lithium concentration parameter calculated by the first relationship, and the target current density parameter output by the second model are input into the third model, and the maximum strain of the target battery in the positive electrode thickness direction, the maximum strain of the target battery in the diaphragm thickness direction, and the maximum strain of the target battery in the negative electrode thickness can be obtained. Then the expansion displacement in each direction is calculated, and finally the expansion displacement in each direction is added to obtain the total displacement of the target battery, that is, the target expansion displacement of the target battery.

[0150] In another optional embodiment, the present application may also use the first model, the second model and the fourth model as a whole model to perform the above temperature parameter calculation. The construction of the whole model is exemplarily described below:

[0151] First, a geometric model of the target battery is constructed.

[0152] Among them, the geometric model of the target battery is used to simulate the target battery itself, so the physical parameters of the target battery are needed. These physical parameters include, for example, the thickness of the positive electrode of the target battery, the thickness of the negative electrode of the target battery, the thickness of the diaphragm of the target battery, the particle size of the positive electrode active material of the target battery, the particle size of the negative electrode active material of the target battery, the porosity of the target battery diaphragm, the solid phase volume fraction of the positive electrode of the target battery, the liquid phase volume fraction of the positive electrode of the target battery, the solid phase volume fraction of the negative electrode of the target battery, the liquid phase volume fraction of the negative electrode of the target battery, etc.

[0153] The geometric model of the target battery can be constructed based on the physical parameters of the target battery itself. If the data generated by the target battery charging and discharging process is to be calculated through the target model, it is necessary to establish a link between the geometric model and the target model.

[0154] Then, an initial model is constructed, which includes an initial first model and an initial fourth model. After the current temperature is input, the initial first model and the initial fourth model can output multiple groups of power parameters, lithium concentration parameters and temperature parameters.

[0155] Since the feasibility of the initial first model and the initial fourth model cannot be confirmed, it is necessary to manually charge and discharge the real target battery, and then actually measure the various parameters of the target battery, and compare the actually measured parameters with the parameters output by the initial first model and the initial fourth model. According to the comparison results, the feasibility of the initial first model and the initial fourth model is verified. If the verified feasibility is poor, the initial first model and the initial fourth model need to be calibrated.

[0156] Exemplarily, when the initial first model and the initial fourth model need to be corrected, at least one of the parameters such as the reaction rate constant of the positive and negative electrodes, the positive and negative electrode diffusion coefficients, the positive and negative electrode diffusion activation energy, the Brugg coefficient at the positive and negative electrodes and the diaphragm in the initial first model and the initial fourth model can be corrected.

[0157] Since the target battery will be affected by the generation, regeneration, and precipitation of lithium ions of the solid electrolyte interface film during the charge and discharge process, and the charge and discharge time and life of the target battery, that is, side reactions will occur, after the initial first model and the initial fourth model are calibrated, the coupling relationship between the second model and the first model and the fourth model obtained by the correction is continued to be established to obtain the intermediate model. For the same reason, the intermediate model still needs to be calibrated. The correction method is the same as the above method, which can be to compare the measured data with the data output by the model, and determine whether the intermediate model needs to be calibrated according to the comparison results. When correction is required, at least one parameter such as the current density of the solid electrolyte interface film generation reaction, the current density of the solid electrolyte interface film regeneration reaction, the conductivity of the solid electrolyte interface film, and the current density of the lithium precipitation reaction can be corrected to obtain the corrected intermediate model, that is, the overall model.

[0158] In addition, the present application may use the third model as a separate model in combination with the above-mentioned overall model to execute the battery expansion displacement determination method of the present application.

[0159] It should be noted here that the present application may obtain the third model according to the following method:

[0160] constructing an initial third model, wherein the initial third model is used to output the expansion displacement of the target battery;

[0161] Based on the difference between the expansion displacement of the target battery and the preset expansion displacement, the initial third model is parameter-corrected to obtain the third model.

[0162] When it is determined that the initial third model needs to be corrected, it can be corrected by adjusting the current density of the SEI generation reaction, the conductivity of the SEI film, the Young's modulus E of the electrode material, the Poisson's ratio ν of the electrode material, and the thermal expansion coefficient α T The initial ground three-dimensional model is calibrated by adjusting the value of at least one of the items.

[0163] Below, the battery material is ternary, the positive electrode material is ternary, the negative electrode material is graphite, and the electrolyte uses LiPF6 solvent material as the target battery, and the target battery is cyclically charged and discharged at a constant power as an example, and the expansion displacement determination method of the battery provided in the present application is exemplarily described:

[0164] First, a geometric model is constructed based on the physical parameters of the target battery.

[0165] Among them, the physical parameters of the target battery are negative electrode thickness 77.4um, diaphragm thickness 13um, positive electrode thickness 56.45um, negative electrode particle diameter 12.7um, positive electrode particle diameter 4um, negative electrode solid phase volume fraction 0.66, positive electrode solid phase volume fraction 0.738, negative electrode liquid phase volume fraction 0.275, positive electrode liquid phase volume fraction 0.207, diaphragm porosity 0.42, negative electrode maximum lithium insertion concentration 30555mol / m^3, positive electrode maximum lithium insertion concentration 49211mol / m^3.

[0166] Second, set the cycle conditions in the model as follows:

[0167] (1) Charge to 4.3V at 1C (78A) constant current and constant voltage;

[0168] (2) Stand for 1800 seconds;

[0169] (3) Discharge at a constant current of 1C (78A) to 2.75V.

[0170] Third, set the preset condition to target battery capacity ≤ 80%;

[0171] Fourth, the initial temperature was set to 25 °C, together with the negative electrode reaction rate constant of 5.4e-11m / s, the positive electrode reaction rate constant of 2e-11m / s, the negative electrode diffusion coefficient of 7.9e-14m^2 / s, the positive electrode diffusion coefficient of 8.8e-14m^2 / s, the negative electrode diffusion activation energy of 50000J / mol, the positive electrode diffusion activation energy of 49000J / mol, the negative electrode Brugg coefficient of 1.85, the positive electrode Brugg coefficient of 1.9, the separator Brugg coefficient of 1.9, and the negative electrode conductivity of 460 S / m, positive electrode conductivity 111S / m, electrolyte initial concentration 1050mol / m^3, negative electrode density 2240kg / m^3, positive electrode density 4600kg / m^3, diaphragm density 1210kg / m^3, negative electrode thermal conductivity 2.6W / (m·K), positive electrode thermal conductivity 2.4W / (m·K), diaphragm thermal conductivity 2W / (m·K), negative electrode specific heat capacity 881J / (kg·K), positive electrode specific heat capacity 1001J / (kg·K), diaphragm specific heat capacity 1978J / ( kg·K), SEI film density 2690kg / m^3, SEI film molar mass 0.05kg / mol, SEI generation current density 3.03E-11A / m^2, SEI generation equilibrium potential 0.4V, initial film thickness 5nm, SEI film conductivity 7e-7S / m, positive electrode current collector thermal expansion coefficient 23.6e-6 (1 / K), positive electrode thermal expansion coefficient 8.62e-6 (1 / K), separator thermal expansion coefficient 1.33e-4 (1 / K), negative electrode thermal expansion coefficient 4 .06e-6 (1 / K), the thermal expansion coefficient of the negative electrode collector is 1.7-5 (1 / K), the Young's modulus of the positive electrode collector is 70 GPa, the Poisson's ratio of the positive electrode collector is 0.34, the Young's modulus of the positive electrode is 0.4 GPa, the Poisson's ratio of the positive electrode is 0.32, the Young's modulus of the separator is 0.5 GPa, the Poisson's ratio of the separator is 0.35, the Young's modulus of the negative electrode is 0.5 GPa, the Poisson's ratio of the negative electrode is 0.3, the Young's modulus of the negative electrode collector is 117 GPa, and the Poisson's ratio of the negative electrode collector is 0.35, which are input into the target model together.

[0172] Fifth, when the capacity of the target battery meets the preset conditions, the target expansion displacement of the target battery is output.

[0173] like Figure 8 and Fig. 9 The figure shows the result of predicting the expansion displacement of the target battery. By fitting the measured capacity retention rate of 800 cycles and the expansion displacement during the cycle, it can be predicted that the number of cycles corresponding to the EOL state (80% capacity retention rate) of the ternary battery cell during the cycle is 2900, at which time the expansion displacement of the target battery is the largest, and its expansion displacement is 4.01mm.

[0174] It should be noted that although the operations of the method of the present invention are described in a particular order in the accompanying drawings, this does not require or imply that the operations must be performed in the particular order, or that all the operations shown must be performed to achieve the desired results. On the contrary, the steps depicted in the flowchart can be performed in a different order. For example, ... Additionally or alternatively, some steps can be omitted, multiple steps can be combined into one step, and / or one step can be decomposed into multiple steps. For example, . . .

[0175] Further references Fig.10 , which shows a structural block diagram of a computer device according to an embodiment of the present application.

[0176] The computer device comprises a memory and a processor, and when the computer program is executed by the processor, any one of the above-mentioned battery parameter determination methods is implemented.

[0177] In particular, according to the embodiments of the present disclosure, the above reference Figure 1-7 The described processes may be implemented as computer software programs. For example, embodiments of the present disclosure include a computer program product comprising a computer program tangibly embodied on a machine-readable medium, the computer program comprising a computer program for executing Figure 1-7 The program code of the method.

[0178] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present invention. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, program segment or a part of a code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the square box can also occur in a different order from the order marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0179] The units or modules involved in the embodiments described in the present application may be implemented by software or hardware. The units or modules described may also be arranged in a processor, for example, may be described as: a processor includes an XX unit, a YY unit, and a ZZ unit. The names of these units or modules do not, in some cases, constitute a limitation on the unit or module itself, for example, the XX unit may also be described as a "unit for XX".

[0180] As another aspect, the present application further provides a computer-readable storage medium, which may be a computer-readable storage medium included in the device described in the above embodiment; or a computer-readable storage medium that exists independently and is not assembled into the device. The computer-readable storage medium stores one or more programs, and the programs are used by one or more processors to execute the formula input method described in the present application.

[0181] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A method for determining expansion displacement of a battery, characterized in that: include: Acquire a current temperature of the target battery, calculate temperature parameters based on the current temperature, the first model, the second model, and the fourth model, and obtain initial temperature parameters; The temperature parameter calculation includes inputting the current temperature into the first model to calculate the power parameter and the lithium concentration parameter, and inputting the current temperature into the second model to calculate the current density of the target battery to obtain the initial power parameter and the initial current density parameter; Wherein, the inputting the current temperature into the first model for power parameter calculation and lithium concentration parameter calculation includes: inputting the current temperature into a first relational equation of the first model, the first relational equation outputting lithium intercalation and deintercalation reaction current density, overpotential, solid phase potential and liquid phase potential of the lithium intercalation and deintercalation reaction, the first relational equation being used to describe the intercalation and deintercalation reaction of the target battery during a charge and discharge process; the first relational equation is related to the positive and negative electrode equilibrium potentials of the target battery, the positive and negative electrode equilibrium potentials of the target battery are determined by the second relational equation in the first model, the second relational equation being used to describe the diffusion of lithium ions inside the target battery during a charge and discharge process of the target battery; The solid phase potential is input into the third relational equation of the first model to obtain the solid phase current density and the first lithium concentration parameter, and the third relational equation is used to describe the solid phase charge conservation of the target battery during a charge and discharge process; the current temperature and the liquid phase potential are input into the fourth relational equation of the first model to obtain the liquid phase current density, and the fourth relational equation is used to describe the liquid phase charge conservation of the target battery during a charge and discharge process, and the fourth relational equation is related to the liquid phase concentration of the target battery, and the liquid phase concentration of the target battery is determined by the fifth relational equation in the first model, and the fifth relational equation is used to describe the diffusion of lithium ions in the electrolyte during a charge and discharge process of the target battery; Wherein, inputting the current temperature into the second model to calculate the current density of the target battery includes: determining the overpotential of the side reaction of the target battery according to the side reaction parameters of the target battery, the solid phase potential and the liquid phase potential; determining the initial current density parameter according to the overpotential, Faraday constant, transfer coefficient, gas constant, exchange current density of the target battery and the current temperature; Inputting the initial power parameter and the initial current density parameter into the fourth model to calculate the temperature parameter and obtain the initial temperature parameter, including: inputting the lithium deintercalation reaction current density, the overpotential of the lithium deintercalation reaction, and the initial current density parameter into the fourth model to obtain polarization heat generation power and reversible heat generation power; inputting the solid phase current density and the solid phase potential into the fourth model to obtain solid phase ohmic heat generation power; inputting the liquid phase current density and the liquid phase potential into the fourth model to obtain liquid phase ohmic heat generation power; obtaining the initial temperature parameter according to the polarization heat generation power, the reversible heat generation power, the solid phase ohmic heat generation power, the liquid phase ohmic heat generation power and the fourth model; Determining whether the current capacity of the target battery meets a preset condition; If not, the current temperature is updated to the initial temperature parameter, and power parameter calculation, lithium concentration parameter calculation, current density calculation and temperature parameter calculation are cyclically performed according to the initial temperature parameter, the first model, the second model and the fourth model until the capacity of the target battery meets the preset condition; When the capacity of the target battery meets a preset condition, the target lithium concentration parameter obtained by the first model, the target current density parameter of the target battery obtained by the second model, and the target temperature parameter obtained by the fourth model are input into the third model to obtain the target expansion displacement of the target battery, including: Inputting the target temperature parameter, the target lithium concentration parameter and the target current density parameter into a third model, obtaining the maximum strain of the target battery in the positive electrode thickness direction, the maximum strain of the target battery in the separator thickness direction and the maximum strain of the target battery in the negative electrode thickness; The product of the maximum strain of the target battery in the thickness direction of the positive electrode and the initial thickness of the positive electrode of the target battery is taken as the first expansion displacement of the target battery in the thickness direction of the positive electrode; The product of the maximum strain of the target battery in the separator thickness direction and the initial thickness of the target battery separator is used as the second expansion displacement of the target battery in the separator thickness direction; The product of the maximum strain of the target battery on the thickness of the negative electrode and the initial thickness of the negative electrode of the target battery is taken as the third expansion displacement of the target battery in the thickness direction of the negative electrode; A sum of the first expansion displacement, the second expansion displacement, and the third expansion displacement is determined as a target expansion displacement of the target battery.

2. The method according to claim 1, characterized in that: The determining whether the current capacity of the target battery meets a preset condition includes: Obtaining a constant current of the target battery during the charging and discharging process; Obtaining the discharge time of the target battery during a charge and discharge process; Integrate the constant current according to the discharge time to obtain the current capacity of the target battery after one charge and discharge; Comparing the current capacity with the battery capacity after the last charge and discharge; If the ratio of the current capacity to the battery capacity is greater than or equal to a preset threshold, it is determined that the current capacity of the target battery does not meet the preset condition.

3. The method according to claim 1, characterized in that: The first relationship is related to the current density of the lithium intercalation and deintercalation reaction, the anode transfer coefficient of the target battery, the cathode transfer coefficient of the target battery, the exchange current density of the lithium intercalation and deintercalation reaction, the Faraday constant, the gas constant, the overpotential of the lithium intercalation and deintercalation reaction, the temperature, the solid phase potential, the liquid phase potential, the equilibrium potential of the positive and negative electrodes of the target battery, and the potential drop; The second relationship is related to the lithium concentration in the solid phase, the active particle radius and the solid phase effective diffusion coefficient; The third relationship is related to the solid phase current density, the solid phase effective conductivity and the solid phase potential; The fourth relationship is related to liquid phase current density, liquid phase effective conductivity, thermodynamic factor, lithium ion transport number, liquid phase concentration, the Faraday constant, the gas constant, the temperature and the liquid phase potential; The fifth relationship is related to the liquid phase volume fraction, the current density, the liquid phase effective diffusion coefficient, the lithium ion transport number, the active particle specific surface area, the liquid phase concentration and the Faraday constant.

4. The method according to claim 1, characterized in that: The method further comprises: constructing an initial third model, wherein the initial third model is used to output the expansion displacement of the target battery; Based on the difference between the expansion displacement of the target battery and the preset expansion displacement, the initial third model is parameter-corrected to obtain the third model.

5. The method according to claim 1, characterized in that The method further comprises: Constructing a geometric model of the target battery according to the design parameters of the target battery, wherein the geometric model is used to perform charge and discharge simulation on the target battery; Simulation parameters generated by the geometric model during the charge and discharge simulation of the target battery are obtained.

6. The method according to claim 5, characterized in that The temperature parameter calculation based on the current temperature, the first model, the second model and the fourth model includes: Inputting the current temperature, the first model parameter of the first model and the simulation parameter into the first model to perform power parameter calculation and lithium concentration parameter calculation to obtain the initial power parameter; Inputting the current temperature, the second model parameter of the second model and the simulation parameter into the second model to calculate the current density, so as to obtain the initial current density parameter; The initial power parameter, the initial current density parameter, the fourth model parameter of the fourth model and the simulation parameter are input into the fourth model to perform temperature parameter calculation to obtain the initial temperature parameter.

7. The method according to claim 1, characterized in that The first relation is: in, and are the transfer coefficients of the anode and cathode, respectively, is the lithium insertion and extraction reaction current density, is the exchange current density of lithium insertion and extraction reaction, F is the Faraday constant, R is the gas constant, is the overpotential of lithium insertion and extraction reaction, T is the temperature, is the solid phase potential, is the liquid phase potential, is the equilibrium potential of the positive and negative electrodes, is the potential drop caused by all side reactions; The second relation is: in, is the lithium concentration in the solid phase, is the radius of the active particle, is the solid phase effective diffusion coefficient, is the discharge duration; The third relational expression is: in, is the solid phase current density, is the solid phase effective conductivity, is the solid phase potential; The fourth relational expression is: in, is the liquid phase current density, is the liquid effective conductivity, is the thermodynamic factor, is the lithium ion transport number, is the liquid concentration, is the liquid phase potential, F is the Faraday constant, R is the gas constant, and T is the temperature.

8. The method according to claim 1, characterized in that: The second model is: in, Generates side reaction current density for solid electrolyte interface film, Generates the side reaction exchange current density for the solid electrolyte interface film, is the transfer coefficient, is the equilibrium potential of the solid electrolyte interface film, is the potential drop caused by all side reactions, is the overpotential for the side reaction, R is the gas constant, T is the temperature parameter, F is the Faraday constant, is the solid phase potential, is the liquid phase potential.

9. A computer device, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps in the method according to any one of claims 1 to 8 when executing the computer program.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

11. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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