Methods, devices, storage media, and electronic equipment used to determine the charging and discharging efficiency of battery cells.

Abstract

A method and apparatus for determining the charging / discharging performance of a battery cell, a storage medium, and an electronic device. The method comprises: obtaining a pre-configured target battery cell model, wherein the target battery cell model is used for simulating the charging / discharging performance of a target battery cell at a preset environment temperature, and the target battery cell comprises a battery cell made of at least two layers of coated electrodes (S101); simulating, by means of the target battery cell model, the process that the target battery cell is charged at a constant-current rate or discharged at the constant-current rate at the preset environment temperature according to a first preset current (S102); determining target performance parameters of the target battery cell according to the simulation result, wherein the target performance parameters comprise charging performance parameters when the target battery cell is charged at the constant-current rate at the preset environment temperature, or comprise discharging performance parameters when the target battery cell is discharged at the constant-current rate at the preset environment temperature (S103).

Description

Method, device, storage medium and electronic device for determining battery cell charge and discharge performance

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on May 17, 2021, with application number 202110535290.X and invention name “Method, device, storage medium and electronic device for determining the charge and discharge performance of a battery cell”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of battery cell performance testing, and specifically, to a method, device, storage medium, and electronic device for determining the charge and discharge performance of a battery cell. Background Art

[0003] With the urgent market demand for new energy vehicles, power battery companies also need to speed up the iteration of battery cells and shorten the R&D cycle. In order to improve the performance of battery cells, relevant technologies have proposed a double-layer coated positive electrode plate, which improves the compatibility between coatings and avoids the dissolution problem of the internal coating caused by the double-layer coating. It improves the flatness of the electrode surface, effectively improves the safety performance of lithium-ion batteries, and also improves the battery's rate performance and cycle performance. However, the specific improvement in the performance of battery cells made with multi-layer structured electrodes generally requires actual measurement, and a large number of experiments are required to optimize the optimal thickness of the multi-layer structure. However, the experimental and actual measurement process of the electrochemical performance of the battery cells requires a lot of manpower and material resources, and the time cost is relatively high, which in turn affects the iteration speed of the battery cells.

[0004] Summary of the Invention

[0005] The purpose of this application is to provide a method, device, storage medium and electronic device for determining the charge and discharge performance of a battery cell.

[0006] In a first aspect, a method for determining the charge and discharge performance of a battery cell is provided, the method comprising: obtaining a preset target battery cell model, the target battery cell model being used to simulate the charge and discharge performance of the target battery cell at a preset ambient temperature, the target battery cell comprising a battery cell made of at least two layers of coated electrodes; simulating a process of constant current rate charging or constant current rate discharging of the target battery cell according to a first preset current at the preset ambient temperature through the target battery cell model; determining target performance parameters of the target battery cell based on the simulation results, the target performance parameters comprising charging performance parameters when the target battery cell is charged at a constant current rate at the preset ambient temperature, or comprising discharge performance parameters when the target battery cell is discharged at a constant current rate at the preset ambient temperature.

[0007] Optionally, the target performance parameters include the lithium ion concentration distribution and potential distribution on the target battery cell; the simulation results include the lithium ion concentrations at different positions of the target battery cell, the solid-phase potentials at different positions, and the liquid-phase potentials at different positions obtained at multiple preset moments; determining the target performance parameters of the target battery cell based on the simulation results includes: determining the lithium ion concentration distribution of the target battery cell at the target moment based on the lithium ion concentrations at different positions of the target battery cell obtained at multiple preset moments; determining the potential distribution of the target battery cell at the target moment based on the solid-phase potentials at different positions of the target battery cell and the liquid-phase potentials at different positions obtained at multiple preset moments.

[0008] Optionally, the target battery cell model includes a one-dimensional battery cell model, a two-dimensional battery cell model or a three-dimensional battery cell model, wherein the one-dimensional battery cell model is used to simulate the lithium ion concentration distribution and the potential distribution in the preset thickness direction of the target battery cell; the two-dimensional battery cell model is used to simulate the lithium ion concentration distribution and the potential distribution in the preset thickness direction and preset height direction of the target battery cell; the three-dimensional battery cell model is used to simulate the lithium ion concentration distribution and the potential distribution in the preset thickness direction, preset height direction and preset length direction of the target battery cell.

[0009] Optionally, the target performance parameters include the capacity and energy corresponding to the target battery cell, and the simulation results include the target time for constant current rate charging or constant current rate discharging of the target battery cell according to the first preset current and the battery cell simulation voltages measured at different preset times, and the target time includes the charging cutoff time or the discharging cutoff time; determining the target performance parameters of the target battery cell based on the simulation results includes: determining the energy corresponding to the target battery cell based on the target time and the battery cell simulation voltages measured at different preset times; and determining the capacity corresponding to the target battery cell based on the target time.

[0010] Optionally, the target performance parameters include a target cell temperature at at least one designated position on the target cell, and the simulation results include cell temperatures collected by temperature sensing devices set at different preset positions, and the designated positions include any of the preset positions; determining the target performance parameters of the target cell based on the simulation results includes: using the cell temperature collected by the temperature sensing device set at the designated position as the target cell temperature.

[0011] Optionally, the target battery cell model includes an electrochemical model and a solid heat transfer model; the electrochemical model is used to simulate the electrochemical performance of the target battery cell during the charging and discharging process, and the solid heat transfer model is used to simulate the temperature transfer of the target battery cell during the charging and discharging process.

[0012] Optionally, the target cell model is pre-established in the following manner:

[0013] Obtain preset model parameters, wherein the preset model parameters include custom parameters, battery cell design parameters, electrochemical parameters, and thermodynamic parameters; establish a finite element electrochemical geometric model and a finite element solid heat transfer geometric model corresponding to the target battery cell, and set the material properties of each area in the finite element electrochemical geometric model and the finite element solid heat transfer geometric model according to the user's trigger operation; obtain user-defined model input parameters and model output parameters; establish the target battery cell model according to the preset model parameters, the model input parameters, the model output parameters, the finite element electrochemical geometric model with set material properties, and the finite element solid heat transfer geometric model with set material properties.

[0014] In a second aspect, a device for determining charge and discharge performance of a battery cell is provided, the device comprising:

[0015] An acquisition module is used to acquire a preset target battery cell model, wherein the target battery cell model is used to simulate the charge and discharge performance of the target battery cell at a preset ambient temperature, and the target battery cell includes a battery cell made of at least two layers of coated electrodes; a simulation module is used to simulate the process of constant current rate charging or constant current rate discharging of the target battery cell according to a first preset current at the preset ambient temperature through the target battery cell model; a determination module is used to determine the target performance parameters of the target battery cell according to the simulation results, wherein the target performance parameters include the charging performance parameters when the target battery cell is charged at a constant current rate at the preset ambient temperature, or include the discharge performance parameters when the target battery cell is discharged at a constant current rate at the preset ambient temperature.

[0016] Optionally, the target performance parameters include the lithium ion concentration distribution and potential distribution on the target battery cell; the simulation results include the lithium ion concentrations at different positions of the target battery cell, the solid-phase potentials at different positions, and the liquid-phase potentials at different positions obtained at multiple preset moments; the determination module is used to determine the lithium ion concentration distribution of the target battery cell at the target moment based on the lithium ion concentrations at different positions of the target battery cell obtained at multiple preset moments; and determine the potential distribution of the target battery cell at the target moment based on the solid-phase potentials at different positions of the target battery cell and the liquid-phase potentials at different positions obtained at multiple preset moments.

[0017] Optionally, the target battery cell model includes a one-dimensional battery cell model, a two-dimensional battery cell model or a three-dimensional battery cell model, wherein the one-dimensional battery cell model is used to simulate the lithium ion concentration distribution and the potential distribution in the preset thickness direction of the target battery cell; the two-dimensional battery cell model is used to simulate the lithium ion concentration distribution and the potential distribution in the preset thickness direction and preset height direction of the target battery cell; the three-dimensional battery cell model is used to simulate the lithium ion concentration distribution and the potential distribution in the preset thickness direction, preset height direction and preset length direction of the target battery cell.

[0018] Optionally, the target performance parameters include the capacity and energy corresponding to the target battery cell, and the simulation results include the target time for constant current rate charging or constant current rate discharging of the target battery cell according to the first preset current and the battery cell simulation voltages measured at different preset times, wherein the target time includes the charging cutoff time or the discharging cutoff time; the determination module is used to determine the energy corresponding to the target battery cell based on the battery cell simulation voltages measured at the target time and at different preset times; and determine the capacity corresponding to the target battery cell based on the target time.

[0019] Optionally, the target performance parameter includes a target cell temperature at at least one specified position on the target cell, and the simulation result includes the cell temperature collected by the temperature sensing device set at different preset positions, and the specified position includes any of the preset positions; the determination module is used to use the cell temperature collected by the temperature sensing device set at the specified position as the target cell temperature.

[0020] Optionally, the target battery cell model includes an electrochemical model and a solid heat transfer model; the electrochemical model is used to simulate the electrochemical performance of the target battery cell during the charging and discharging process, and the solid heat transfer model is used to simulate the temperature transfer of the target battery cell during the charging and discharging process.

[0021] Optionally, the target cell model is pre-established in the following manner:

[0022] Obtain preset model parameters, wherein the preset model parameters include custom parameters, battery cell design parameters, electrochemical parameters, and thermodynamic parameters; establish a finite element electrochemical geometric model and a finite element solid heat transfer geometric model corresponding to the target battery cell, and set the material properties of each area in the finite element electrochemical geometric model and the finite element solid heat transfer geometric model according to the user's trigger operation; obtain user-defined model input parameters and model output parameters; establish the target battery cell model according to the preset model parameters, the model input parameters, the model output parameters, the finite element electrochemical geometric model with set material properties, and the finite element solid heat transfer geometric model with set material properties.

[0023] In a third aspect, a non-temporary computer-readable storage medium is provided, on which a computer program is stored, which, when executed by a processor, implements the steps of the method described in the first aspect of the present application.

[0024] In a fourth aspect, an electronic device is provided, comprising: a memory on which a computer program is stored; and a processor for executing the computer program in the memory to implement the steps of the method described in the first aspect of the present application.

[0025] Through the above technical solution, a pre-set target battery cell model is obtained, and the target battery cell model is used to simulate the charge and discharge performance of the target battery cell at a preset ambient temperature, and the target battery cell includes a battery cell made of at least two layers of coated electrodes; the target battery cell model is used to simulate the process of constant current rate charging or constant current rate discharging of the target battery cell according to a first preset current at the preset ambient temperature; the target performance parameters of the target battery cell are determined according to the simulation results, and the target performance parameters include the charging performance parameters when the target battery cell is charged at a constant current rate at the preset ambient temperature, or include the discharge performance parameters when the target battery cell is discharged at a constant current rate at the preset ambient temperature. In this way, the charge and discharge performance of the battery cell made of at least two layers of coated electrodes can be determined by simulation, so that the battery cell design can be optimized according to the target performance parameters obtained by simulation, without the need for actual measurement and a large amount of experimental optimization, which speeds up the R&D process, shortens the R&D cycle, reduces labor costs, time costs and battery cell production costs, and realizes rapid product iteration of battery cell design.

[0026] Other features and advantages of the present application will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings are used to provide a further understanding of the present application and constitute a part of the specification. Together with the following detailed description, they are used to explain the present application but do not constitute a limitation of the present application. In the accompanying drawings:

[0028] FIG1 is a flow chart showing a method for determining charge and discharge performance of a battery cell according to an exemplary embodiment;

[0029] FIG2 is a schematic diagram showing the relationship between an electrochemical model and a solid heat transfer model according to an exemplary embodiment;

[0030] FIG3 is a schematic structural diagram of a one-dimensional battery cell model according to an exemplary embodiment;

[0031] FIG4 is a schematic structural diagram of a two-dimensional battery cell model according to an exemplary embodiment;

[0032] FIG5 is a schematic structural diagram of a three-dimensional battery cell model according to an exemplary embodiment;

[0033] FIG6 is a flow chart showing a method for establishing a target cell model according to an exemplary embodiment;

[0034] FIG7 is a block diagram of a device for determining charge and discharge performance of a battery cell according to an exemplary embodiment;

[0035] Fig. 8 is a structural block diagram of an electronic device according to an exemplary embodiment. DETAILED DESCRIPTION

[0036] The following describes the specific embodiments of the present application in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present application and are not intended to limit the present application.

[0037] First, the application scenario of this application is introduced. This application is mainly used in the scenario of charging and discharging performance testing of a target battery cell made of multiple layers of coated electrodes during the design and development of a battery cell, wherein the target battery cell refers to a battery cell made of at least two layers of coated electrodes, and the positive or negative electrode of the battery cell can be made of multiple coatings.

[0038] In order to determine the performance of battery cells made of multi-layer coated electrodes, the existing technology generally requires actual measurement to know the results, and a large number of experiments are required to optimize the optimal thickness of the multi-layer structure. However, the experimental and actual measurement process of the electrochemical performance of the battery cells requires a lot of manpower and material resources, and the time cost is relatively high, which in turn affects the iteration speed of the battery cells.

[0039] In order to solve the above-mentioned problems, the present application provides a method, device, storage medium and electronic device for the charge and discharge performance of a battery cell, which can determine the charge and discharge performance of a battery cell made of at least two layers of coated electrodes through simulation, so that the battery cell design can be optimized according to the target performance parameters obtained by simulation, without the need for actual measurement and a large number of experimental optimizations, thereby accelerating the R&D process, shortening the R&D cycle, reducing labor costs, time costs and battery cell production costs, and realizing rapid product iteration of battery cell design.

[0040] The specific implementation methods of this application are described in detail below with reference to the accompanying drawings.

[0041] FIG1 is a flow chart showing a method for determining charge and discharge performance of a battery cell according to an exemplary embodiment. As shown in FIG1 , the method includes the following steps:

[0042] In step S101 , a preset target cell model is obtained, where the target cell model is used to simulate the charge and discharge performance of a target cell at a preset ambient temperature. The target cell includes a cell made of at least two layers of coated electrodes.

[0043] Among them, the target battery cell model includes an electrochemical model and a solid heat transfer model. The electrochemical model is used to simulate the electrochemical performance of the target battery cell during the charging and discharging process, and the solid heat transfer model is used to simulate the temperature transfer of the target battery cell during the charging and discharging process; the preset ambient temperature includes but is not limited to any of the following temperatures: -30℃, -10℃, 0℃, 25℃, 45℃, 60℃.

[0044] Figure 2 is a schematic diagram of the relationship between an electrochemical model and a solid heat transfer model according to an exemplary embodiment. As shown in Figure 2, the electrochemical model can be used to calculate the heat generated by the electrochemical reaction, and the heat is coupled to the solid heat transfer model to convert it into the temperature change of the battery core. The temperature is then coupled to the electrochemical model. The temperature-sensitive parameters in the electrochemical model will change with the change of temperature, thereby realizing the interaction between electrochemistry and solid heat transfer.

[0045] In addition, the electrochemical model may include a finite element electrochemical geometric model, and the solid heat transfer model may include a finite element solid heat transfer geometric model. In one possible implementation, the user (generally referring to the battery cell designer) can pre-establish the target battery cell model by using COMSOL Mutiphysics software (the specific model establishment process will be described below).

[0046] In step S102, a process of performing constant current rate charging or constant current rate discharging of the target battery cell according to a first preset current at the preset ambient temperature is simulated by the target battery cell model.

[0047] The first preset current may be a cell charging current or a cell discharging current arbitrarily set by a cell designer according to current test requirements.

[0048] In one possible implementation, a preset rate can be selected from multiple preset rates as the current rate, and the current rate, the preset ambient temperature and the first preset current can be used as variable values ​​of the custom parameters in the target battery cell model. In this way, after the user triggers the charging or discharging simulation instruction, the terminal can simulate the process of charging or discharging the target battery cell at a constant current rate (that is, the current rate, such as 0.33C, 1C, 2C, etc.) at the preset ambient temperature according to the first preset current through the target battery cell model in the COMSOL Mutiphysics software, and then obtain the target time (the target time includes the charging cutoff time or the discharging cutoff time) when the target battery cell is charged or discharged at a constant current rate according to the first preset current at the preset ambient temperature, the battery cell simulation voltage at different preset times, and the battery cell simulation temperature at different preset positions of the battery cell at different preset times, and other performance parameters output by the model.

[0049] It should be noted that, based on the above-mentioned simulation method, the results of charge and discharge simulation tests of the target battery cell at multiple preset ambient temperatures and multiple preset rates can be obtained. Specifically, for each preset ambient temperature, simulation curves corresponding to multiple preset rates at the preset ambient temperature can be simulated to obtain the target performance parameters of the target battery cell when charged and discharged at different charge and discharge rates at the same ambient temperature. The target performance parameters of the target battery cell at the same charge and discharge rate corresponding to different ambient temperatures can also be determined.

[0050] In step S103, target performance parameters of the target battery cell are determined based on the simulation results, and the target performance parameters include charging performance parameters when the target battery cell is charged at a constant current rate at the preset ambient temperature, or discharge performance parameters when the target battery cell is discharged at a constant current rate at the preset ambient temperature.

[0051] Among them, the target performance parameters may include but are not limited to one or more of the following parameters: the capacity and energy corresponding to the target battery cell, the lithium ion concentration distribution and potential distribution on the target battery cell, and the target battery cell temperature at at least one specified position on the target battery cell. The simulation results may include but are not limited to one or more of the following results: the lithium ion concentrations at different positions of the target battery cell obtained at multiple preset times, the solid phase potentials and liquid phase potentials at different positions obtained at multiple preset times, the target time for constant current rate charging or constant current rate discharging of the target battery cell according to the first preset current (the target time may include the charging cutoff time or the discharging cutoff time), the battery cell simulation voltages measured at different preset times, and the battery cell temperature collected by the temperature sensing device arranged at different preset positions, and the temperature sensing device may include a temperature probe.

[0052] It should be noted that the underlying mass conservation equation and charge conservation equation can be built-in for the target battery model in advance. In this way, when the charging or discharging process of the target battery is simulated based on the target battery model, the lithium ion concentration of the target battery at different preset times can be calculated by the model through the mass conservation equation and the initial value of the lithium ion concentration, the solid phase potential of the target battery at different preset times can be calculated by the model through the charge conservation equation and the initial value of the solid phase potential, and the liquid phase potential of the target battery at different preset times can be calculated by the model through the charge conservation equation and the initial value of the liquid phase potential; in addition, temperature probes can be defined at different positions of the target battery cell, and the temperature changes at different positions of the battery cell can be observed through the temperature probes. The different positions may include the positive pole, negative pole, large surface center, pole group center, etc. of the battery cell. This is only an example and the present application does not limit this.

[0053] The following describes the determination process of the above different target performance parameters respectively.

[0054] In the process of determining the lithium ion concentration distribution of the target battery cell based on the simulation results, the lithium ion concentration distribution of the target battery cell at the target moment can be determined based on the lithium ion concentrations of different positions of the target battery cell obtained at multiple preset moments, wherein the target moment can be any moment among the multiple preset moments, or any moment between any two adjacent preset moments specified by the user.

[0055] If the target moment is any of the multiple preset moments, one implementation method may be to obtain the lithium ion concentration of the target battery cell at different positions obtained by simulation at the target moment, and then use the position of the negative electrode current collector in the electrochemical geometric model as the coordinate origin, the distance from the coordinate origin as the horizontal coordinate, and the lithium ion concentration as the vertical coordinate to draw a graph to obtain the lithium ion concentration distribution of the target battery cell, so that the user can timely understand the lithium ion movement of the target battery cell during the charging or discharging process according to the lithium ion concentration distribution displayed in the coordinate graph, and then optimize the design of the battery cell based on this.

[0056] If the target moment is any moment between any two adjacent preset moments, in one implementation method, the lithium ion concentrations of the target battery cell at different positions corresponding to the two adjacent preset moments can be obtained. Then, for the lithium ion concentration at each position, the lithium ion concentration at the target moment can be calculated by interpolation based on the lithium ion concentrations simulated at the two adjacent preset moments at the position. Thereafter, a graph can be drawn in a manner similar to that described in the previous paragraph to obtain the lithium ion concentration distribution of the target battery cell at different positions at the target moment.

[0057] In the process of determining the potential distribution of the target battery cell based on the simulation results, the potential distribution of the target battery cell at the target moment can be determined based on the solid-phase potential at different positions of the target battery cell and the liquid-phase potential at different positions obtained at multiple preset moments. The potential of the battery cell is equal to the difference between the solid-phase potential and the liquid-phase potential. In a possible implementation method of the present application, the preset position of the target battery cell (such as the position of the negative electrode current collector) can also be used as the coordinate origin, and the distance from the preset position is used as the horizontal axis, and the difference between the solid-phase potential and the liquid-phase potential at each position at different positions is used as the vertical axis to draw a graph to determine the potential distribution of the target battery cell.

[0058] In the process of determining the capacity and energy of the target battery cell based on the simulation results, the energy corresponding to the target battery cell can be determined based on the target time in the simulation results and the simulated voltage of the battery cell measured at different preset times; and the capacity corresponding to the target battery cell can be determined based on the target time.

[0059] Specifically, the capacity and energy of the target cell can be calculated by writing the following global ordinary differential and differential algebraic equations into the target cell model:

[0060]

[0061]

[0062] Wherein, W represents the energy of the target cell, Q represents the capacity of the target cell, I represents the constant current charge and discharge current (ie, the first preset current), E cell Indicates the simulated cell voltage of the target cell.

[0063] In addition, the target performance parameter also includes a target cell temperature at at least one specified position on the target cell. The specified position can be any preset position. In the process of determining the target cell temperature of the target cell based on the simulation result, the cell temperature collected by the temperature sensing device set at the specified position can be used as the target cell temperature.

[0064] Based on the above implementation steps, before producing the target battery cell, the constant current rate charge and discharge process of the target battery cell at different preset ambient temperatures can be simulated, and the performance of this target battery cell can be known based on the simulation results, so as to optimize the battery cell design based on the determined performance of the target battery cell. For example, the rated capacity of the target battery cell is 84Ah (ampere-hour), and the actual capacity (or actual capacity) of the target battery cell during constant current charging is determined to be 78Ah. At this time, the battery cell design can be optimized by appropriately reducing the thickness of the electrode, increasing the conductive agent, increasing the porosity of the porous electrode, reducing the particle size of the positive / negative active material, etc., so that the optimized target battery cell meets the charging and discharging performance requirements, thereby accelerating the R&D process, shortening the R&D cycle, reducing labor costs, time costs and battery cell production costs, and realizing rapid product iteration of battery cell design.

[0065] In order to enable users to promptly know the lithium ion concentration distribution and potential distribution of the target battery cell in different dimensions during the charging or discharging process during the battery cell design and development stage, in the present application, a one-dimensional battery cell model, a two-dimensional battery cell model and a three-dimensional battery cell model can be pre-established, that is, the target battery cell model can include a one-dimensional battery cell model, a two-dimensional battery cell model or a three-dimensional battery cell model, wherein the one-dimensional battery cell model is used to simulate the lithium ion concentration distribution and the potential distribution in the preset thickness direction of the target battery cell; the two-dimensional battery cell model is used to simulate the lithium ion concentration distribution and the potential distribution in the preset thickness direction and the preset height direction of the target battery cell; the three-dimensional battery cell model is used to simulate the lithium ion concentration distribution and the potential distribution of the target battery cell in all directions.

[0066] For example, Figure 3 is a structural schematic diagram of a one-dimensional battery cell model according to an exemplary embodiment, Figure 4 is a structural schematic diagram of a two-dimensional battery cell model according to an exemplary embodiment, and Figure 5 is a structural schematic diagram of a three-dimensional battery cell model according to an exemplary embodiment. In the geometric model structures of the target battery cells shown in Figures 3, 4 and 5, the positive electrode of the target battery cell includes two coatings as an example. As shown in Figure 3, the geometric structure of the one-dimensional battery cell model is, from left to right, a negative electrode current collector, a negative electrode porous electrode, a separator, a positive electrode porous electrode coating 2, a positive electrode porous electrode coating 1, and a positive electrode current collector. In this way, assuming that lithium ions only move in the preset thickness direction of the battery cell, based on the one-dimensional battery cell model, it can be known that the target battery cell moves in the preset thickness direction. The lithium ion concentration distribution and potential distribution in the direction (from left to right in the battery cell geometry as shown in FIG3 ); as shown in FIG4 , the two-dimensional battery cell model is obtained by stretching the one-dimensional battery cell model in the preset height direction. In this way, assuming that the lithium ions only move in the preset thickness direction and the preset height direction of the battery cell, the lithium ion concentration distribution and potential distribution of the target battery cell in the preset thickness direction and the preset height direction can be obtained based on the two-dimensional battery cell model; as shown in FIG5 , it is a three-dimensional battery cell model of the target battery cell. The three-dimensional battery cell model is the same as the actual battery cell structure. Based on the three-dimensional battery cell model, the lithium ion concentration distribution and potential distribution of the target battery cell in all directions can be obtained. The above examples are only illustrative and this application does not limit this.

[0067] It should be noted that in the process of simulating the target battery model to obtain the charge and discharge performance parameters of the target battery, after the user triggers the target button (such as "Start Simulation" or "Model Calculation", etc.), the model can calculate by itself. After the calculation is completed, the corresponding target performance parameters can be called to draw a visual map. For example, the voltage-time curve, voltage-capacity curve, capacity-power curve, battery temperature-time curve, etc. can be drawn. The change of lithium ion concentration in the solid or liquid phase during the charging or discharging process of the battery can also be drawn. Based on the three-dimensional battery model, the temperature distribution cloud map, the potential distribution of the porous electrode, the current density distribution and the solid or liquid phase lithium ion concentration distribution cloud map can also be called, so that the charge and discharge performance of the target battery can be more intuitively displayed to the user.

[0068] By using the above method, the charge and discharge performance of a battery cell made of at least two layers of coated electrodes can be determined through simulation, so that the battery cell design can be optimized based on the target performance parameters obtained by simulation, without the need for actual measurements and a large number of experimental optimizations. This speeds up the R&D process, shortens the R&D cycle, reduces labor costs, time costs and battery cell production costs, and realizes rapid product iteration of battery cell design.

[0069] In addition, the lithium ion concentration distribution or potential distribution of the battery cell in different dimensional directions can be determined based on the battery cell models in different dimensions, thereby providing reference data in different dimensions for the research and development and design of the battery cell.

[0070] FIG6 is a flow chart showing a method for establishing a target cell model according to an exemplary embodiment. As shown in FIG6 , the method includes the following steps:

[0071] In step S601 , preset model parameters are obtained, where the preset model parameters include custom parameters, cell design parameters, electrochemical parameters, and thermodynamic parameters.

[0072] Among them, the custom parameters may include a custom charge and discharge rate and a preset ambient temperature, the battery cell design parameters may include the design size of the target battery cell, the electrochemical parameters may include the parameters shown in Table 1 and the maximum state of charge of the porous positive electrode, the minimum state of charge of the porous positive electrode, the maximum state of charge of the porous negative electrode, the minimum state of charge of the porous negative electrode, the initial electrolyte salt concentration, the Brugmann coefficient and other parameters of the target battery cell, and the thermodynamic parameters may include the convective heat transfer coefficient and the equilibrium potential temperature derivative of the positive and negative electrode materials.

[0073]

[0074] Table 1

[0075] In one possible implementation, the electrochemical parameters and cell design parameters of the target cell can be collected by consulting literature or conducting tests based on commonly used electrochemical equations (such as Fick's second law, Butler-Volmer equation, and Nernst-Plank equation) to obtain the initial values ​​of the preset model parameters.

[0076] In step S602, a finite element electrochemical geometric model and a finite element solid heat transfer geometric model corresponding to the target battery cell are established, and the material properties of each region in the finite element electrochemical geometric model and the finite element solid heat transfer geometric model are set according to the user's triggering operation.

[0077] For example, taking the target battery cell with a positive electrode made of two coatings as an example, first draw a three-dimensional finite element electrochemical geometric model of the target battery cell with a six-layer structure, as shown in Figure 5. The six-layer structure is the positive electrode current collector, the positive electrode porous electrode coating 1, the positive electrode porous electrode coating 2, the separator, the negative electrode porous electrode, and the negative electrode current collector. Then, the corresponding regional attributes and material properties are assigned to different regions, where the regional attributes can include positive and negative electrode active materials, electrolytes, separators, and current collectors. For example, the corresponding regional attributes can be embedded in the "Region Properties" interface in the model interface, and then the corresponding electrolyte material domain or positive and negative electrode active materials can be selected in the corresponding defined geometric area in the "Lithium-ion Battery" interface. Furthermore, the material properties corresponding to different regions can also be set, where the material properties of the positive and negative electrodes include conductivity, solid-phase diffusion coefficient, equilibrium potential, temperature derivative of equilibrium potential, reference concentration, maximum and minimum charge states of the electrode, etc. Since the pores of the diaphragm entity are filled with electrolyte, it is necessary to give the diaphragm the properties of the electrolyte, including liquid-phase diffusion coefficient, electrolyte conductivity, transfer number, activity correlation, etc., and give the positive or negative electrode current collector the properties of aluminum or copper, including conductivity. The above is only an example and this application does not limit it.

[0078] The following describes the pre-establishment process of the target cell model by taking a lithium-ion battery whose positive electrode is made of two coatings as an example.

[0079] First, the properties of the negative porous electrode can be defined. According to the user's trigger operation, the negative electrode material properties set by the user are obtained, and the temperature, active material volume fraction, porosity, effective electrolyte conductivity and effective solid phase diffusion coefficient of the porous electrode are further determined. The porous electrode reaction temperature and electrode kinetic expression are defined, the particle intercalation temperature and initial lithium ion concentration are defined, and the lithium ion concentration transfer model is selected. In the solid phase particles of lithium-ion batteries, the diffusion of lithium is generally defined by Fick's second law, and the particle size is defined. In addition, the active materials of the negative electrode include but are not limited to: graphite, silicon oxide, lithium metal, etc.

[0080] Secondly, define the properties of the positive porous electrode coatings 1 and 2. This process is similar to the process of defining the properties of the negative porous electrode and will not be repeated here. The positive electrode coatings 1 and 2 can be the same positive electrode material or different positive electrode materials, wherein the positive electrode materials include but are not limited to: lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide, nickel cobalt lithium manganese oxide, etc. The thickness and porosity of the coatings 1 and 2 can be set according to actual conditions. In addition, considering that the volume fraction and porosity of the active materials of the two coatings may be different, the porosity of the coating close to the current collector side can be set lower than the porosity of the coating close to the diaphragm side when designing the battery cell.

[0081] After that, the separator, positive and negative current collectors, electrical grounding and electrode current, and initial battery charge distribution can be defined in sequence, and meshing can be performed so that finite element calculations can be performed based on a finite number of small units after division.

[0082] After establishing the above electrochemical geometric model, the solid heat transfer geometric model of the target battery cell can be established. According to different simulation requirements, a simplified geometric model or a real geometric model consistent with the actual battery cell structure can be used. For example, the simplified geometric model can be a rectangular parallelepiped consistent with the actual battery cell size, or a simple geometric model that simplifies some structural parts. There is no restriction on the model structure of the simplified geometric model and the real geometric model. The material properties of each region in the solid heat transfer geometric model (such as constant pressure heat capacity, density, thermal conductivity, etc.) can then be defined. Specifically, the user can define the material properties of each region in the solid heat transfer geometric model according to the battery cell. For each type of structural material, the theoretical value or experimental measured value of the corresponding material is imported respectively, and then the solid heat transfer model is set up, including setting the temperature of the solid (except the pole group), selecting the corresponding material properties, defining the external temperature of the battery cell, defining the equivalent thermal conductivity in different directions, defining the heat source, selecting the pole group domain as the heat source, coupling the heat generation in the electrochemical model to the solid heat transfer model, defining the heat exchange (or heat flux) between the battery cell and the external environment, and defining the convection heat transfer coefficient (generally 10-20W*m-2*K-1), and setting the external temperature, that is, the ambient temperature of the battery cell.

[0083] At this point, the electrochemical geometric model and solid heat transfer geometric model corresponding to the target battery cell have been established.

[0084] In step S603, user-defined model input parameters and model output parameters are obtained.

[0085] Among them, the model input parameters may include current density, and the model output parameters may include battery voltage, cell temperature, and the charging cut-off time or discharging cut-off time when the simulation stop condition is met. The stop condition can be set to the upper or lower limit of the cell voltage, or to the upper limit of the cell temperature. This application does not limit this.

[0086] In step S604, the target battery cell model is established according to the preset model parameters, the model input parameters, the model output parameters, the finite element electrochemical geometric model with set material properties, and the finite element solid heat transfer geometric model with set material properties.

[0087] At this point, the target cell model corresponding to the target cell is established, and different preset ambient temperatures correspond to different target cell models.

[0088] It should also be noted that during the model construction process, the number of coating layers and the basic properties of the active materials coated in each layer can be flexibly adjusted according to actual conditions. The basic properties include: the solid-phase diffusion coefficient of the positive and negative electrode materials, electrical conductivity, maximum lithium ion concentration, equilibrium potential of the material, and the temperature derivative of the equilibrium potential.

[0089] FIG7 shows a device for determining charge and discharge performance of a battery cell according to an exemplary embodiment. As shown in FIG7 , the device includes:

[0090] An acquisition module 701 is configured to acquire a preset target cell model, wherein the target cell model is configured to simulate the charge and discharge performance of a target cell at a preset ambient temperature, wherein the target cell comprises a cell formed of at least two layers of coated electrodes;

[0091] A simulation module 702 is configured to simulate, through the target cell model, a process of constant current rate charging or constant current rate discharging of the target cell according to a first preset current at the preset ambient temperature;

[0092] Determination module 703 is used to determine the target performance parameters of the target battery cell based on the simulation results, and the target performance parameters include the charging performance parameters when the target battery cell is charged at a constant current rate at the preset ambient temperature, or the discharge performance parameters when the target battery cell is discharged at a constant current rate at the preset ambient temperature.

[0093] Optionally, the target performance parameter includes a lithium ion concentration distribution and a potential distribution on the target battery cell; the simulation result includes lithium ion concentrations at different positions of the target battery cell, solid-phase potentials at different positions, and liquid-phase potentials at different positions, respectively, obtained at a plurality of preset moments;

[0094] The determination module 703 is used to determine the lithium ion concentration distribution of the target battery cell at the target time based on the lithium ion concentrations at different positions of the target battery cell obtained at multiple preset moments; and to determine the potential distribution of the target battery cell at the target time based on the solid-phase potential at different positions and the liquid-phase potential at different positions of the target battery cell obtained at multiple preset moments.

[0095] Optionally, the target battery cell model includes a one-dimensional battery cell model, a two-dimensional battery cell model or a three-dimensional battery cell model, wherein the one-dimensional battery cell model is used to simulate the lithium ion concentration distribution and the potential distribution in the preset thickness direction of the target battery cell; the two-dimensional battery cell model is used to simulate the lithium ion concentration distribution and the potential distribution in the preset thickness direction and preset height direction of the target battery cell; the three-dimensional battery cell model is used to simulate the lithium ion concentration distribution and the potential distribution in the preset thickness direction, preset height direction and preset length direction of the target battery cell.

[0096] Optionally, the target performance parameter includes the capacity and energy corresponding to the target battery cell, and the simulation result includes a target time for constant current rate charging or constant current rate discharging of the target battery cell according to the first preset current and a battery cell simulation voltage measured at different preset times, wherein the target time includes a charging cutoff time or a discharging cutoff time;

[0097] The determination module 703 is configured to determine the energy corresponding to the target cell according to the target time and the simulated voltages of the cell measured at different preset times; and to determine the capacity corresponding to the target cell according to the target time.

[0098] Optionally, the target performance parameter includes a target cell temperature at at least one designated location on the target cell; the simulation result includes cell temperatures collected by temperature sensing devices disposed at different preset locations;

[0099] The determining module 603 is configured to use the battery cell temperature collected by the temperature sensing device disposed at the designated location as the target battery cell temperature.

[0100] Optionally, the target battery cell model includes an electrochemical model and a solid heat transfer model; the electrochemical model is used to simulate the electrochemical performance of the target battery cell during the charging and discharging process, and the solid heat transfer model is used to simulate the temperature transfer of the target battery cell during the charging and discharging process.

[0101] Optionally, the target cell model is pre-established in the following manner:

[0102] Obtain preset model parameters, which include custom parameters, battery cell design parameters, electrochemical parameters, and thermodynamic parameters; establish a finite element electrochemical geometric model and a finite element solid heat transfer geometric model corresponding to the target battery cell, and set the material properties of each area in the finite element electrochemical geometric model and the finite element solid heat transfer geometric model according to the user's trigger operation; obtain user-defined model input parameters and model output parameters; establish the target battery cell model according to the preset model parameters, the model input parameters, the model output parameters, the finite element electrochemical geometric model with set material properties, and the finite element solid heat transfer geometric model with set material properties.

[0103] Regarding the apparatus in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0104] By using the above-mentioned device, the charge and discharge performance of a battery cell made of at least two layers of coated electrodes can be determined through simulation, so that the battery cell design can be optimized based on the target performance parameters obtained by simulation, without the need for actual measurements and a large number of experimental optimizations. This speeds up the R&D process, shortens the R&D cycle, reduces labor costs, time costs and battery cell production costs, and realizes rapid product iteration of battery cell design.

[0105] FIG8 is a block diagram of an electronic device 800 according to an exemplary embodiment. As shown in FIG8 , the electronic device 800 may include a processor 801 and a memory 802. The electronic device 800 may also include one or more of a multimedia component 803, an input / output (I / O) interface 804, and a communication component 805.

[0106] Among them, the processor 801 is used to control the overall operation of the electronic device 800 to complete all or part of the steps in the above-mentioned method for determining the charge and discharge performance of the battery cell. The memory 802 is used to store various types of data to support the operation of the electronic device 800. These data may include, for example, instructions for any application or method used to operate on the electronic device 800, as well as application-related data, such as contact data, messages sent and received, pictures, audio, video, etc. The memory 802 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk. The multimedia component 803 may include a screen and an audio component. The screen may be, for example, a touch screen, and the audio component is used to output and / or input audio signals. For example, the audio component may include a microphone for receiving external audio signals. The received audio signals may be further stored in the memory 802 or transmitted via the communication component 805. The audio component also includes at least one speaker for outputting audio signals. The I / O interface 804 provides an interface between the processor 801 and other interface modules. The aforementioned other interface modules may be a keyboard, a mouse, buttons, etc. These buttons may be virtual buttons or physical buttons. The communication component 805 is used for wired or wireless communication between the electronic device 800 and other devices. Wireless communication, such as Wi-Fi, Bluetooth, Near Field Communication (NFC), 2G, 3G, 4G, NB-IOT, eMTC, or other 5G, etc., or a combination of one or more thereof, is not limited here. Therefore, the corresponding communication component 805 may include: a Wi-Fi module, a Bluetooth module, an NFC module, etc.

[0107] In an exemplary embodiment, the electronic device 800 can be implemented by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components to execute the above-mentioned method for determining the charge and discharge performance of a battery cell.

[0108] In another exemplary embodiment, a computer-readable storage medium including program instructions is further provided. When executed by a processor, the program instructions implement the steps of the above-described method for determining the charge and discharge performance of a battery cell. For example, the computer-readable storage medium may be the above-described memory 802 including the program instructions. The above-described program instructions may be executed by the processor 801 of the electronic device 800 to implement the above-described method for determining the charge and discharge performance of a battery cell.

[0109] In another exemplary embodiment, a computer program product is further provided. The computer program product includes a computer program that can be executed by a programmable device. The computer program has a code portion for executing the above-mentioned method for determining the charge and discharge performance of a battery cell when executed by the programmable device.

[0110] The above describes in detail the optional implementation methods of the present application in conjunction with the accompanying drawings. However, the present application is not limited to the specific details of the above implementation methods. Within the technical concept of the present application, various simple modifications can be made to the technical solution of the present application, and these simple modifications all fall within the scope of protection of the present application.

[0111] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner unless there is any contradiction. In order to avoid unnecessary repetition, this application will not further describe various possible combinations.

[0112] In addition, the various implementation methods of the present application may be arbitrarily combined, and as long as they do not violate the concept of the present application, they should also be regarded as the contents disclosed in the present application.

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