Battery capacity attenuation curve generation method and device, electronic equipment and storage medium

Abstract

The invention discloses a battery capacity attenuation curve generation method and device, electronic equipment and a storage medium, and relates to the technical field of battery life prediction. The method comprises the following steps: acquiring total reaction current density and cathode deposition parameters of the lithium ion battery in different time steps in each simulation cycle period; the total reaction current density comprises a first lithium intercalation reaction current density, a first solid electrolyte membrane growth side reaction current density and a first lithium precipitation side reaction current density which are calculated through a pseudo two-dimensional electrochemical model; the negative electrode deposition parameters comprise negative electrode particle surface solid electrolyte membrane concentration and metal lithium concentration calculated through an electrochemical model; according to the total reaction current density and the negative electrode deposition parameters, calculating the battery capacity corresponding to each simulation cycle period, and accumulating the total cycle times; and when the battery capacity or the total cycle index reaches the preset threshold value, the capacity attenuation curve is generated based on the battery capacity and the total cycle index, so that the accuracy of the prediction result is improved.

Description

Technical Field

[0001] The present application relates to the technical field of battery life prediction, and in particular to a method, device, electronic device and storage medium for generating a battery capacity decay curve. Background Art

[0002] With the gradual depletion of oil resources and the increasing awareness of environmental protection, lithium-ion batteries and other recyclable batteries have received more and more attention. In long-life cycle applications such as new energy vehicles and energy storage cabinets, quickly predicting the capacity decay of lithium-ion batteries is one of the key difficulties.

[0003] At present, the relevant technology uses the pseudo-two-dimensional (P2D) electrochemical model of lithium-ion batteries to predict capacity decay, but this process ignores the adverse effects caused by the long-term accumulation of side reactions, resulting in low accuracy of the results of long-term cycle simulation, especially for the prediction of nonlinear decay. Summary of the invention

[0004] In view of the above-mentioned defects or deficiencies in the related art, it is desired to provide a method, device, electronic device and storage medium for generating a battery capacity decay curve, which can improve the accuracy of the prediction results.

[0005] In a first aspect, the present application provides a method for generating a battery capacity attenuation curve, the method comprising:

[0006] Obtaining the total reaction current density and negative electrode deposition parameters of the lithium-ion battery at different time steps in each simulated cycle, wherein the total reaction current density includes the first lithium insertion reaction current density, the first solid electrolyte membrane growth side reaction current density, and the first lithium deposition side reaction current density calculated by the pseudo two-dimensional electrochemical model, and the negative electrode deposition parameters include the solid electrolyte membrane concentration on the surface of the negative electrode particles and the metal lithium concentration calculated by the pseudo two-dimensional electrochemical model;

[0007] According to the total reaction current density and the negative electrode deposition parameters, the battery capacity corresponding to each simulated cycle period is calculated respectively, and the total number of cycles is accumulated;

[0008] When the battery capacity or the total number of cycles reaches a preset threshold, a capacity decay curve of the lithium-ion battery is generated based on the battery capacity and the total number of cycles.

[0009] Optionally, in some embodiments of the present application, the total reaction current density is obtained by the following steps:

[0010] Using the side reaction current density of the previous iteration step and the second lithium insertion reaction current density, respectively calculate the solid electrolyte membrane growth side reaction overpotential and the lithium precipitation side reaction overpotential, wherein the side reaction current density includes the second solid electrolyte membrane growth side reaction current density and the second lithium precipitation side reaction current density;

[0011] According to the solid electrolyte membrane growth side reaction overpotential and the lithium deposition side reaction overpotential, updating and obtaining the first solid electrolyte membrane growth side reaction current density and the first lithium deposition side reaction current density;

[0012] The first lithium insertion reaction current density and the total reaction current density are updated according to the first solid electrolyte membrane growth side reaction current density and the first lithium deposition side reaction current density.

[0013] Optionally, in some embodiments of the present application, the negative electrode deposition parameters are obtained by the following steps:

[0014] Acquiring an area ratio of the negative electrode particles, wherein the area ratio is related to an initial porosity of the negative electrode particles;

[0015] The solid electrolyte membrane concentration and the metal lithium concentration are calculated and obtained according to the aspect ratio, the first solid electrolyte membrane growth side reaction current density and the first lithium deposition side reaction current density.

[0016] Optionally, in some embodiments of the present application, the porosity of the negative electrode particles is obtained by the following steps:

[0017] The thickness of the deposited film on the surface of the negative electrode particles is calculated based on the area ratio, the solid electrolyte membrane concentration, and the metal lithium concentration, and the porosity of the negative electrode particles is calculated based on the deposited film thickness.

[0018] Optionally, in some embodiments of the present application, the parameters of the pseudo two-dimensional electrochemical model are adjusted by the following steps:

[0019] According to the upper limit of membrane resistance and the lower limit of porosity corresponding to the lithium-ion battery, the conductivity and porosity reduction parameters of the solid electrolyte membrane are set respectively;

[0020] The experimentally measured capacity decay curve is divided into a linear decay segment and a nonlinear decay segment according to the inflection point, and the first diffusion coefficient of ethylene carbonate in the electrolyte is adjusted using the experimental data of the linear decay segment and the gradient descent method, and the first lithium precipitation model correction parameter and the first lithium precipitation side reaction exchange current density are adjusted using the experimental data of the nonlinear decay segment and the gradient descent method.

[0021] Optionally, in some embodiments of the present application, the step of adjusting the first diffusion coefficient of ethylene carbonate in the electrolyte by using the experimental data of the linear attenuation segment and the gradient descent method comprises:

[0022] The second diffusion coefficient at the reference temperature and the corresponding activation energy of the ethylene carbonate side reaction model are corrected by the experimental data of the linear attenuation section and the gradient descent method, and the first diffusion coefficient is calculated based on the second diffusion coefficient and the corresponding activation energy of the ethylene carbonate side reaction model.

[0023] Optionally, in some embodiments of the present application, the step of adjusting the first lithium deposition model correction parameter and the first lithium deposition side reaction exchange current density by using the experimental data of the nonlinear attenuation segment and the gradient descent method includes:

[0024] Correcting the second lithium deposition model correction parameters and the corresponding activation energy of the lithium deposition side reaction model at the reference temperature by using the experimental data of the nonlinear attenuation section and the gradient descent method, and calculating the first lithium deposition model correction parameters based on the second lithium deposition model correction parameters and the corresponding activation energy of the lithium deposition side reaction model;

[0025] The second lithium deposition side reaction exchange current density and the corresponding activation energy of the lithium deposition side reaction at the reference temperature are corrected by the experimental data of the nonlinear attenuation section and the gradient descent method, and the first lithium deposition side reaction exchange current density is calculated based on the second lithium deposition side reaction exchange current density and the corresponding activation energy of the lithium deposition side reaction.

[0026] In a second aspect, the present application provides a battery capacity decay curve generating device, the battery capacity decay curve generating device comprising:

[0027] An acquisition module is configured to obtain the total reaction current density and negative electrode deposition parameters of the lithium-ion battery at different time steps in each simulation cycle, wherein the total reaction current density includes a first lithium insertion reaction current density, a first solid electrolyte membrane growth side reaction current density, and a first lithium deposition side reaction current density calculated by a pseudo two-dimensional electrochemical model, and the negative electrode deposition parameters include a solid electrolyte membrane concentration on the surface of negative electrode particles and a metal lithium concentration calculated by the pseudo two-dimensional electrochemical model;

[0028] A calculation module, configured to calculate the battery capacity corresponding to each simulated cycle period according to the total reaction current density and the negative electrode deposition parameter, and accumulate the total number of cycles;

[0029] A generating module is configured to generate a capacity decay curve of the lithium-ion battery based on the battery capacity and the total number of cycles when the battery capacity or the total number of cycles reaches a preset threshold.

[0030] In a third aspect, the present application provides an electronic device, comprising a processor and a memory, wherein the memory stores at least one instruction, at least one program, a code set or an instruction set, and the instruction, the program, the code set or the instruction set is loaded and executed by the processor to implement the steps of the battery capacity decay curve generation method described in any one of the first aspects.

[0031] In a fourth aspect, the present application provides a computer-readable storage medium, which stores one or more programs, and the one or more programs can be executed by one or more processors to implement the steps of the battery capacity decay curve generation method described in any one of the first aspects.

[0032] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:

[0033] The embodiments of the present application provide a method, device, electronic device and storage medium for generating a battery capacity decay curve. By adding the solid electrolyte membrane growth side reaction process and the lithium deposition side reaction process to a pseudo two-dimensional electrochemical model, and obtaining the total reaction current density and negative electrode deposition parameters at different time steps based on the model, it is possible to comprehensively reflect the impact of the long-term accumulation of side reactions, and then calculate the battery capacity corresponding to each simulated cycle period based on the total reaction current density and the negative electrode deposition parameters, and generate a capacity decay curve that is closer to the actual situation, thereby improving the accuracy of the prediction results. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 A schematic diagram of a flow chart of a method for generating a battery capacity decay curve provided in an embodiment of the present application;

[0036] Figure 2 A schematic diagram of a graphite particle surface chemical reaction provided in an embodiment of the present application;

[0037] Figure 3 A schematic diagram of a process for adjusting parameters of a pseudo two-dimensional electrochemical model provided in an embodiment of the present application;

[0038] Figure 4 A schematic diagram of a power capacity attenuation curve of a lithium-ion battery under different charge and discharge cycle conditions provided in an embodiment of the present application;

[0039] Figure 5 A structural block diagram of a battery capacity decay curve generating device provided in an embodiment of the present application;

[0040] Figure 6 A structural block diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0042] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0043] 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. Figures 1 to 6 The battery capacity decay curve generation method, device, electronic device and storage medium provided in the embodiments of the present application are described in detail.

[0044] Please refer to Figure 1 , which is a flow chart of a method for generating a battery capacity decay curve provided in an embodiment of the present application, the method specifically comprising the following steps:

[0045] S101, obtaining the total reaction current density and negative electrode deposition parameters of the lithium-ion battery at different time steps in each simulated cycle period, wherein the total reaction current density includes the first lithium insertion reaction current density, the first solid electrolyte membrane growth side reaction current density and the first lithium deposition side reaction current density calculated by the pseudo two-dimensional electrochemical model, and the negative electrode deposition parameters include the solid electrolyte membrane concentration on the surface of the negative electrode particles and the metallic lithium concentration calculated by the pseudo two-dimensional electrochemical model.

[0046] It should be noted that the embodiment of the present application uses a pseudo-two-dimensional electrochemical model to simulate basic electrochemical processes such as the migration and diffusion of lithium ions between the positive and negative electrodes, and adds aging processes such as the solid electrolyte interphase (SEI) growth side reaction process and the lithium precipitation side reaction process. Among them, the growth mechanism of the solid electrolyte membrane is that ethylene carbonate (EC) diffuses through the old solid electrolyte membrane in the electrolyte to the surface of the negative electrode graphite particles and reacts with lithium ions (Li +) reacts to synthesize lithium ethylene carbonate (CH2OCO2Li) deposition. In addition, if the negative overpotential of the battery is negative, a lithium deposition side reaction will occur. Figure 2 The chemical equations of the three reactions are shown as follows:

[0047]

[0048] For example, in the process of obtaining the total reaction current density, the embodiment of the present application first uses the side reaction current density of the previous iteration step and the second lithium insertion reaction current density in each time step of each charge or discharge cycle simulation to calculate the solid electrolyte membrane growth side reaction overpotential and the lithium precipitation side reaction overpotential, respectively, wherein the side reaction current density includes the second solid electrolyte membrane growth side reaction current density and the second lithium precipitation side reaction current density. If the time is 0, the side reaction current density of the previous iteration step is 0, and if the time is not 0, the side reaction current density of the previous iteration step is the corresponding value of the previous time step. For example, the solid electrolyte membrane growth side reaction overpotential σ sei and lithium deposition side reaction overpotential σ li It can be calculated by the following formula:

[0049]

[0050] In formula (2), represents the solid phase potential, represents the liquid phase potential, U sei represents SEI equilibrium potential, f represents Faraday constant, R film represents the deposited film impedance, j int represents the lithium insertion reaction current density, j sei represents the current density of the solid electrolyte membrane growth side reaction, a frc_li represents the correction parameter of lithium precipitation model, and its value range is 0 to 1, j li represents the current density of the lithium deposition side reaction. In the embodiment of the present application, the variable j can be solved according to the pseudo two-dimensional electrochemical model. int To declare and define the solution variable j sei , k li and R film wait.

[0051] Secondly, according to the solid electrolyte membrane growth side reaction overpotential and the lithium deposition side reaction overpotential, the first solid electrolyte membrane growth side reaction current density and the first lithium deposition side reaction current density are updated. sei and lithium deposition side reaction current density k li It can be calculated by the following formula:

[0052]

[0053] In formula (3), j sei It represents the rate constant of the SEI side reaction on the surface of the negative electrode graphite particles, and its value is 1E-12 (m / s). represents the concentration of EC in the electrolyte, R represents the gas constant, T represents the temperature, δ film Denotes the thickness of the deposited film, D EC represents the diffusion coefficient, and its value range is 2E-20(m 2 / s) to 4E-18(m 2 / s), i li It represents the exchange current density of the lithium deposition side reaction on the surface of the negative electrode graphite particles, and its value range is 0.0001 (mol / m 2 s) to 1(mol / m 2 s).

[0054] Finally, the first lithium insertion reaction current density and the total reaction current density are updated based on the first solid electrolyte membrane growth side reaction current density and the first lithium deposition side reaction current density. int and the total reaction current density j total It can be calculated by the following formula:

[0055]

[0056] In formula (4), i int represents the lithium insertion exchange current density, σ int It represents the lithium insertion overpotential, and its value can be calculated by the following formula:

[0057]

[0058] In formula (5), U int represents the lithium insertion equilibrium potential.

[0059] For example, in the process of obtaining the negative electrode deposition parameters (II), the embodiment of the present application first obtains the surface ratio of the negative electrode particles, which is related to the initial porosity of the negative electrode particles. For example, for spherical particles, the surface ratio a is 3*initial porosity / graphite particle radius, and the initial porosity ranges from 0.24 to 0.35. Then, according to the surface ratio, the first solid electrolyte membrane growth side reaction current density and the first lithium precipitation side reaction current density, the solid electrolyte membrane concentration and the metal lithium concentration are calculated respectively, for example, the solid electrolyte membrane concentration c sei and the concentration of metallic lithium c li It can be calculated by material balance relationship, that is,

[0060]

[0061] Furthermore, in the process of obtaining the porosity of the negative electrode particles, the embodiment of the present application can calculate the thickness of the deposited film on the surface of the negative electrode particles according to the surface ratio, the solid electrolyte membrane concentration and the metal lithium concentration, and calculate the porosity of the negative electrode particles based on the deposited film thickness. For example, the deposited film thickness δ film It can be calculated by the following formula:

[0062]

[0063] In formula (7), ρ sei Indicates the density of the SEI film, which is 1690 (kg / m 3 ), M sei represents the molar mass of the SEI film, and its value is 0.162 (kg / mol); ρ li Indicates the density of metallic lithium, which is 534 (kg / m 3 ), M li It represents the molar mass of metallic lithium, and its value is 6.94E-3 (kg / mol).

[0064] The deposited film resistance R film It can be calculated by the following formula:

[0065]

[0066] In formula (8), ω sei represents the volume ratio of SEI film to the deposited film, and its value can be calculated by the ratio of the first half of formula (7) to the total thickness; k sei represents the conductivity of the SEI film, and its value range is 5E-6 (S / m) to 5E-4 (S / m), k li Represents the conductivity of metallic lithium, and its value is 12k sei (S / m).

[0067] For another example, as the thickness of the composite metal lithium layer of the SEI film on the surface of the graphite particles increases, the negative electrode liquid phase porosity ε decreases accordingly, that is,

[0068]

[0069] In formula (9), a frc_pr It represents the porosity reduction parameter, and its value range is from 0 to 1, which ensures the stability of calculation.

[0070] Furthermore, the time integral on both sides of equation (9) gives the calculation formula for porosity:

[0071]

[0072] In formula (10), represents the initial porosity, Indicates the initial film thickness.

[0073] Another example is (III) because the capacity decay curve of lithium-ion batteries depends on the parameter k sei 、a frc_pr , D EC 、a frc_li and i li Different parameter values ​​correspond to different attenuation curves. In order to obtain accurate prediction results, the present embodiment uses experimental data to predict the parameter k. sei 、a frc_pr , D EC 、a frc_li and i li Optionally, the present embodiment can set the solid electrolyte membrane conductivity and porosity reduction parameters according to the upper limit of membrane resistance and the lower limit of porosity corresponding to the lithium-ion battery, for example, by searching the original pseudo-two-dimensional electrochemical model by dichotomy, and the corresponding upper limit of membrane resistance is calculated. and the lower limit of porosity ε limit , and set k accordingly sei and a frc_pr ,Right now

[0074]

[0075] In formula (11), the maximum amount of lithium inserted into the negative electrode is the battery design parameter, and the capacity decay limit is the ratio of the design capacity to the initial capacity after the battery has been cycled for its entire life cycle.

[0076] Then as Figure 3 As shown in FIG. 1 , the experimentally measured capacity decay curve is divided into a linear decay segment and a nonlinear decay segment according to the inflection point, and the first diffusion coefficient D of ethylene carbonate in the electrolyte is adjusted using the experimental data of the linear decay segment and the gradient descent method. EC , so that the mean square error between the experimental data and the simulation data in the linear attenuation section is minimized, and the experimental data of the nonlinear attenuation section and the gradient descent method are used to adjust the correction parameter a of the first lithium precipitation model frc_li and the first lithium deposition side reaction exchange current density i li , so that the mean square error between the experimental data and the simulation data in the nonlinear attenuation section is minimized. For example, the gradient descent method calculates the residual by solving the attenuation curve and comparing it with the experimental data. Then, if the residual does not converge or the maximum number of iterations is not reached, the gradient is calculated, and the gradient and step size are used to calculate the target parameter until the target parameter exceeds the parameter range.

[0077] Furthermore, when simulating variable temperature conditions, the parameter k sei and a frc_pr Keep unchanged, parameter D EC , a frc_li and ili is no longer a constant, but a variable that depends only on temperature. For example, the second diffusion coefficient at the reference temperature can be corrected by the experimental data of the linear attenuation segment and the gradient descent method in the embodiment of the present application. And the activation energy E corresponding to the ethylene carbonate side reaction model EC , and based on the second diffusion coefficient And the activation energy E corresponding to the ethylene carbonate side reaction model EC The first diffusion coefficient is calculated so that the mean square error between the simulated decay curve and the experimental data at all temperatures is minimized, that is,

[0078]

[0079] In formula (12), T ref Indicates the reference temperature.

[0080] For another example, the embodiment of the present application can correct the second lithium precipitation model correction parameter at the reference temperature by using the experimental data of the nonlinear attenuation section and the gradient descent method. And the activation energy E corresponding to the lithium precipitation side reaction model frc_li , and correct the parameters based on the second lithium precipitation model And the activation energy E corresponding to the lithium precipitation side reaction model frc_li The first lithium precipitation model correction parameters are calculated, namely:

[0081]

[0082] Similarly, the embodiment of the present application can correct the exchange current density of the second lithium deposition side reaction at the reference temperature by the experimental data of the nonlinear attenuation section and the gradient descent method. And the activation energy E corresponding to the lithium precipitation side reaction li , and based on the exchange current density of the second lithium deposition side reaction And the activation energy E corresponding to the lithium precipitation side reaction li The exchange current density of the first lithium deposition side reaction is calculated, that is,

[0083]

[0084] S102, according to the total reaction current density and the negative electrode deposition parameters, the battery capacity corresponding to each simulated cycle period is calculated respectively, and the total number of cycles is accumulated.

[0085] For example, the present application embodiment can use the ampere-hour integration method to perform corresponding calculation processing on the total reaction current density to obtain the power capacity of the battery, and can also use formula (15) to calculate the thermal capacity of the battery, that is,

[0086]

[0087] In formula (15), Indicates the maximum lithium insertion coefficient of the negative electrode of the battery, c sei represents the SEI concentration obtained after the charge or discharge process simulation, c li Indicates the concentration of metallic lithium obtained after the simulation of the charging or discharging process is completed. After the simulation of a single charging or discharging process is completed, the parameter c is saved. sei 、c li , ε, δ film and R film , waiting for the next simulation. Each time the solution is repeated, the number of charge and discharge cycles is increased by one, and the corresponding battery capacity is recorded.

[0088] S103, when the battery capacity or the total number of cycles reaches a preset threshold, a capacity decay curve of the lithium-ion battery is generated based on the battery capacity and the total number of cycles.

[0089] For example, Figure 4 As shown, it is a schematic diagram of the power capacity attenuation curve of a lithium-ion battery under different charge and discharge cycle conditions provided by an embodiment of the present application. Among them, curve ① corresponds to the power capacity attenuation curve of a 25-degree 2C rate charge and discharge cycle, curve ② corresponds to the power capacity attenuation curve of a 25-degree 1.5C rate charge and discharge cycle, curve ③ corresponds to the power capacity attenuation curve of a 5-degree 1C rate charge and discharge cycle, curve ④ corresponds to the power capacity attenuation curve of a 25-degree 1C rate charge and discharge cycle, and curve ⑤ corresponds to the power capacity attenuation curve of a 40-degree 1C rate charge and discharge cycle.

[0090] The battery capacity decay curve generation method provided in the embodiment of the present application adds the solid electrolyte membrane growth side reaction process and the lithium deposition side reaction process to the pseudo two-dimensional electrochemical model, and obtains the total reaction current density and the negative electrode deposition parameters at different time steps based on the model. It can comprehensively reflect the impact of the long-term accumulation of side reactions, and then calculate the battery capacity corresponding to each simulated cycle period based on the total reaction current density and the negative electrode deposition parameters, and generate a capacity decay curve that is closer to the actual situation, thereby improving the accuracy of the prediction results.

[0091] Based on the above embodiments, the present application provides a battery capacity decay curve generation device. The battery capacity decay curve generation device 100 can be applied to Figure 1 to Figure 4 In the method for generating the battery capacity attenuation curve of the corresponding embodiment. Please refer to Figure 5 , the battery capacity decay curve generating device 100 comprises:

[0092] An acquisition module 101 is configured to obtain a total reaction current density and negative electrode deposition parameters of a lithium-ion battery at different time steps in each simulation cycle, wherein the total reaction current density includes a first lithium insertion reaction current density, a first solid electrolyte membrane growth side reaction current density, and a first lithium deposition side reaction current density calculated by a pseudo two-dimensional electrochemical model, and the negative electrode deposition parameters include a solid electrolyte membrane concentration on a negative electrode particle surface and a metallic lithium concentration calculated by a pseudo two-dimensional electrochemical model;

[0093] The calculation module 102 is configured to calculate the battery capacity corresponding to each simulated cycle period according to the total reaction current density and the negative electrode deposition parameters, and accumulate the total number of cycles;

[0094] The generating module 103 is configured to generate a capacity decay curve of the lithium-ion battery based on the battery capacity and the total number of cycles when the battery capacity or the total number of cycles reaches a preset threshold.

[0095] Optionally, in some embodiments of the present application, the acquisition module 101 is specifically used to use the side reaction current density of the previous iteration step and the second lithium insertion reaction current density to respectively calculate the solid electrolyte membrane growth side reaction overpotential and the lithium precipitation side reaction overpotential, and the side reaction current density includes the second solid electrolyte membrane growth side reaction current density and the second lithium precipitation side reaction current density;

[0096] According to the solid electrolyte membrane growth side reaction overpotential and the lithium deposition side reaction overpotential, a first solid electrolyte membrane growth side reaction current density and a first lithium deposition side reaction current density are updated;

[0097] According to the first solid electrolyte membrane growth side reaction current density and the first lithium deposition side reaction current density, the first lithium insertion reaction current density and the total reaction current density are updated and obtained.

[0098] Optionally, in some embodiments of the present application, the acquisition module 101 is specifically used to acquire the surface ratio of the negative electrode particles, and the surface ratio is related to the initial porosity of the negative electrode particles;

[0099] According to the aspect ratio, the first solid electrolyte membrane growth side reaction current density and the first lithium deposition side reaction current density, the solid electrolyte membrane concentration and the metal lithium concentration are calculated respectively.

[0100] Optionally, in some embodiments of the present application, the acquisition module 101 is also specifically used to calculate the thickness of the deposited film on the surface of the negative electrode particles according to the area ratio, the solid electrolyte membrane concentration and the metallic lithium concentration, and calculate the porosity of the negative electrode particles based on the deposited film thickness.

[0101] Optionally, in some embodiments of the present application, the acquisition module 101 is specifically used to set the solid electrolyte membrane conductivity and porosity reduction parameters according to the upper limit of membrane resistance and the lower limit of porosity corresponding to the lithium-ion battery;

[0102] The experimentally measured capacity decay curve is divided into a linear decay segment and a nonlinear decay segment according to the inflection point, and the first diffusion coefficient of ethylene carbonate in the electrolyte is adjusted using the experimental data of the linear decay segment and the gradient descent method, and the first lithium precipitation model correction parameters and the first lithium precipitation side reaction exchange current density are adjusted using the experimental data of the nonlinear decay segment and the gradient descent method.

[0103] Optionally, in some embodiments of the present application, the acquisition module 101 is also specifically used to correct the second diffusion coefficient at the reference temperature and the corresponding activation energy of the ethylene carbonate side reaction model through the experimental data of the linear attenuation segment and the gradient descent method, and calculate the first diffusion coefficient based on the second diffusion coefficient and the corresponding activation energy of the ethylene carbonate side reaction model.

[0104] Optionally, in some embodiments of the present application, the acquisition module 101 is further specifically used to correct the second lithium deposition model correction parameters and the corresponding activation energy of the lithium deposition side reaction model at the reference temperature through the experimental data of the nonlinear attenuation segment and the gradient descent method, and calculate the first lithium deposition model correction parameters based on the second lithium deposition model correction parameters and the corresponding activation energy of the lithium deposition side reaction model;

[0105] The exchange current density of the second lithium deposition side reaction and the corresponding activation energy of the lithium deposition side reaction at the reference temperature are corrected by the experimental data of the nonlinear attenuation section and the gradient descent method, and the exchange current density of the first lithium deposition side reaction is calculated based on the exchange current density of the second lithium deposition side reaction and the corresponding activation energy of the lithium deposition side reaction.

[0106] It should be noted that, for the description of the same steps and the same contents in this embodiment as those in other embodiments, reference can be made to the description in other embodiments and will not be repeated here.

[0107] The battery capacity decay curve generating device provided in the embodiment of the present application adds the solid electrolyte membrane growth side reaction process and the lithium deposition side reaction process to the pseudo two-dimensional electrochemical model, and obtains the total reaction current density and the negative electrode deposition parameters at different time steps according to the model. It can comprehensively reflect the impact of the long-term accumulation of side reactions, and then calculate the battery capacity corresponding to each simulated cycle period based on the total reaction current density and the negative electrode deposition parameters, and generate a capacity decay curve that is closer to the actual situation, thereby improving the accuracy of the prediction results.

[0108] Based on the above embodiments, the present application provides an electronic device. Figure 6The electronic device 200 may include a processor 201 and a memory 202. The memory 202 stores at least one instruction, at least one program, code set or instruction set, which is loaded and executed by the processor 201 to implement Figure 1 to Figure 4 The steps of the battery capacity decay curve generation method of the corresponding embodiment.

[0109] As another aspect, the present application provides a computer-readable storage medium for storing program code, the program code for executing the aforementioned Figure 1 to Figure 4 Any implementation manner of the battery capacity decay curve generating method in the corresponding embodiment.

[0110] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and modules described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0111] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the modules is only a logical function division. There may be other division methods in actual implementation, such as multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or modules, which can be electrical, mechanical or other forms. The modules described as separate components may or may not be physically separated, and the components displayed as modules may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the scheme of this embodiment.

[0112] In addition, each functional module in each embodiment of the present application may be integrated into a processing unit, or each module may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of a software functional unit. If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it may be stored in a computer-readable storage medium.

[0113] Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the battery capacity decay curve generation method of each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, etc., various media that can store program codes.

[0114] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0115] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A method for generating a battery capacity attenuation curve, characterized in that: The battery capacity attenuation curve generating method comprises: Obtaining the total reaction current density and negative electrode deposition parameters of the lithium-ion battery at different time steps in each simulated cycle, wherein the total reaction current density includes the first lithium insertion reaction current density, the first solid electrolyte membrane growth side reaction current density, and the first lithium deposition side reaction current density calculated by the pseudo two-dimensional electrochemical model, and the negative electrode deposition parameters include the solid electrolyte membrane concentration on the surface of the negative electrode particles and the metal lithium concentration calculated by the pseudo two-dimensional electrochemical model; According to the total reaction current density and the negative electrode deposition parameters, the battery capacity corresponding to each simulated cycle period is calculated respectively, and the total number of cycles is accumulated; When the battery capacity or the total number of cycles reaches a preset threshold, a capacity decay curve of the lithium-ion battery is generated based on the battery capacity and the total number of cycles.

2. The method for generating a battery capacity attenuation curve according to claim 1, characterized in that: The total reaction current density is obtained by the following steps: Using the side reaction current density of the previous iteration step and the second lithium insertion reaction current density, respectively calculate the solid electrolyte membrane growth side reaction overpotential and the lithium precipitation side reaction overpotential, wherein the side reaction current density includes the second solid electrolyte membrane growth side reaction current density and the second lithium precipitation side reaction current density; According to the solid electrolyte membrane growth side reaction overpotential and the lithium deposition side reaction overpotential, updating and obtaining the first solid electrolyte membrane growth side reaction current density and the first lithium deposition side reaction current density; The first lithium insertion reaction current density and the total reaction current density are updated according to the first solid electrolyte membrane growth side reaction current density and the first lithium deposition side reaction current density.

3. The method for generating a battery capacity attenuation curve according to claim 1, characterized in that: The negative electrode deposition parameters are obtained by the following steps: Obtaining an area ratio of the negative electrode particles, wherein the area ratio is related to an initial porosity of the negative electrode particles; The solid electrolyte membrane concentration and the metal lithium concentration are calculated and obtained according to the aspect ratio, the first solid electrolyte membrane growth side reaction current density and the first lithium deposition side reaction current density.

4. The method for generating a battery capacity attenuation curve according to claim 3, characterized in that: The porosity of the negative electrode particles is obtained by the following steps: The thickness of the deposited film on the surface of the negative electrode particles is calculated based on the area ratio, the solid electrolyte membrane concentration, and the metal lithium concentration, and the porosity of the negative electrode particles is calculated based on the deposited film thickness.

5. The method for generating a battery capacity decay curve according to any one of claims 1 to 4, characterized in that: The parameters of the pseudo two-dimensional electrochemical model are adjusted by the following steps: According to the upper limit of membrane resistance and the lower limit of porosity corresponding to the lithium-ion battery, the solid electrolyte membrane conductivity and porosity reduction parameters are set respectively; The experimentally measured capacity decay curve is divided into a linear decay segment and a nonlinear decay segment according to the inflection point, and the first diffusion coefficient of ethylene carbonate in the electrolyte is adjusted using the experimental data of the linear decay segment and the gradient descent method, and the first lithium precipitation model correction parameter and the first lithium precipitation side reaction exchange current density are adjusted using the experimental data of the nonlinear decay segment and the gradient descent method.

6. The method for generating a battery capacity attenuation curve according to claim 5, characterized in that: The method of adjusting the first diffusion coefficient of ethylene carbonate in the electrolyte by using the experimental data of the linear attenuation section and the gradient descent method comprises: The second diffusion coefficient at the reference temperature and the corresponding activation energy of the ethylene carbonate side reaction model are corrected by the experimental data of the linear attenuation section and the gradient descent method, and the first diffusion coefficient is calculated based on the second diffusion coefficient and the corresponding activation energy of the ethylene carbonate side reaction model.

7. The method for generating a battery capacity attenuation curve according to claim 5, characterized in that: The method of adjusting the first lithium deposition model correction parameter and the first lithium deposition side reaction exchange current density by using the experimental data of the nonlinear attenuation section and the gradient descent method comprises: Correcting the second lithium deposition model correction parameters and the corresponding activation energy of the lithium deposition side reaction model at the reference temperature by using the experimental data of the nonlinear attenuation section and the gradient descent method, and calculating the first lithium deposition model correction parameters based on the second lithium deposition model correction parameters and the corresponding activation energy of the lithium deposition side reaction model; The second lithium deposition side reaction exchange current density and the corresponding activation energy of the lithium deposition side reaction at the reference temperature are corrected by the experimental data of the nonlinear attenuation section and the gradient descent method, and the first lithium deposition side reaction exchange current density is calculated based on the second lithium deposition side reaction exchange current density and the corresponding activation energy of the lithium deposition side reaction.

8. A battery capacity decay curve generating device, characterized in that: The battery capacity decay curve generating device comprises: An acquisition module is configured to obtain the total reaction current density and negative electrode deposition parameters of the lithium-ion battery at different time steps in each simulation cycle, wherein the total reaction current density includes a first lithium insertion reaction current density, a first solid electrolyte membrane growth side reaction current density, and a first lithium deposition side reaction current density calculated by a pseudo two-dimensional electrochemical model, and the negative electrode deposition parameters include a solid electrolyte membrane concentration on the surface of negative electrode particles and a metal lithium concentration calculated by the pseudo two-dimensional electrochemical model; A calculation module, configured to calculate the battery capacity corresponding to each simulated cycle period according to the total reaction current density and the negative electrode deposition parameter, and accumulate the total number of cycles; A generating module is configured to generate a capacity decay curve of the lithium-ion battery based on the battery capacity and the total number of cycles when the battery capacity or the total number of cycles reaches a preset threshold.

9. An electronic device, characterized in that: The electronic device includes a processor and a memory, wherein the memory stores at least one instruction, at least one program, code set or instruction set, and the instruction, the program, the code set or the instruction set is loaded and executed by the processor to implement the steps of the battery capacity decay curve generation method described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores one or more programs, and the one or more programs can be executed by one or more processors to implement the steps of the battery capacity decay curve generating method as described in any one of claims 1 to 7.

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