Method and device for determining size of thinned area and storage medium

Abstract

The invention provides a method and a device for determining the size of a thinned region and a storage medium, which can accurately determine the potential distribution and temperature distribution of a battery cell under different thinned region size designs by adopting an electrochemical-thermal coupling model simulation means, and accurately determine the size of the thinned region by taking the potential distribution and temperature distribution of the battery cell as target functions. And carrying out iterative optimization design on the size parameters of the thinned area. Therefore, the size of the thinned area can be accurately determined without manufacturing test cells in batches, and is not influenced by test process parameters, so that the test and error test cost can be reduced, test resources can be reduced, the product development period can be shortened, the cost can be reduced, the efficiency can be improved, and the accurate size of the thinned area can be obtained.

Description

Technical Field

[0001] The present application relates to the field of battery design technology, and in particular to a method, device and storage medium for determining the size of a thinning area. Background Art

[0002] Lithium-ion batteries are energy storage devices that convert chemical energy into electrical energy based on electrochemical principles. They have the advantages of high energy density, no memory effect, and rechargeability. Therefore, they are widely used in power batteries and large-scale energy storage scenarios. Under the influence of factors such as the continuous development of fast charging technology and harsh battery use environment, battery lithium plating has become one of the common failure modes of lithium-ion batteries. Considering that battery lithium plating will not only lead to a decrease in battery capacity, but also deteriorate battery safety performance, and even cause thermal runaway of the battery in severe cases, battery designers need to adopt a structural design that can delay or avoid battery failure due to lithium plating.

[0003] Under the influence of current distribution uniformity and differences in battery tab design, lithium-ion batteries usually deposit lithium at the tab edge of the battery cell pole piece. Therefore, in order to delay or avoid lithium deposition failure of the battery, the tab edge is generally coated with a thinner coating than the main part of the battery cell pole piece, that is, the coating thickness at the tab edge is less than the coating thickness of the main part, and the area with a smaller coating thickness is called the thinning area.

[0004] At present, the existing technology generally adopts a combination of empirical design and trial and error tests to determine the size of the thinning zone. In this process, multiple groups of thinning zone sizes are first determined based on manual experience, and then test cells are batch-produced based on the multiple groups of thinning zone sizes, and the final thinning zone size is determined based on the performance parameters of the test cells. Since the production cost and production cycle of the test cells are high, and the accuracy of the test process parameters cannot be guaranteed, the existing method for determining the size of the thinning zone not only has the problems of high cost and low efficiency, but also cannot ensure the accuracy of the obtained thinning zone size. Summary of the invention

[0005] The purpose of this application is to solve at least one of the above-mentioned technical defects, especially the technical defects of high cost, low efficiency and low accuracy in the prior art.

[0006] In a first aspect, some embodiments of the present application provide a method for determining the size of a thinning area, comprising:

[0007] Determine the parameter values ​​of each thinning zone size parameter in the current round;

[0008] Generate an electrochemical-thermal coupling model of a target battery cell according to the parameter values ​​of each of the thinning area size parameters in the current round; wherein the target battery cell is a battery cell designed based on the parameter values ​​of each of the thinning area size parameters in the current round;

[0009] Performing simulation calculation based on the electrochemical-thermal coupling model of the target battery cell, and obtaining the potential simulation result of the current round and the temperature simulation result of the current round;

[0010] Determining whether a preset optimization condition is met according to the current round of potential simulation results and the current round of temperature simulation results;

[0011] If satisfied, then the parameter values ​​of the various thinning area size parameters in the current round are output; otherwise, proceed to the next round.

[0012] In one of the embodiments, the electrochemical-thermal coupling model of the target battery cell is a three-dimensional electrochemical-three-dimensional thermal coupling model.

[0013] In one embodiment, each of the thinning area size parameters includes a thinning area height, a maximum thinning thickness, a thinning area inclination angle, and an overhang height, wherein the thinning area inclination angle is used to reflect the linear change of the coating thickness corresponding to the thinning area along the height direction of the battery cell;

[0014] Determining the parameter values ​​of the size parameters of each thinning area in the current round includes:

[0015] If the cell capacity of the target cell is negatively correlated with the inclination angle of the thinning zone, and the current round is not the first round, then according to the preset first boundary constraint condition and the first adjustment strategy, the parameter value of at least one of the thinning zone size parameters is adjusted; wherein the first adjustment strategy is a strategy for preferentially adjusting the parameter values ​​of the thinning zone height, the maximum thinning thickness and / or the overhang height, and adjusting the parameter value of the thinning zone inclination angle in an incremental manner.

[0016] In one embodiment, determining the parameter value of each thinning area size parameter in the current round further includes:

[0017] If the cell capacity is negatively correlated with the inclination angle of the thinning zone, and the current round is the first round, the minimum angle value of the inclination angle of the thinning zone is determined, and the minimum angle value is used as the parameter value of the inclination angle of the thinning zone in the current round.

[0018] In one embodiment, determining the minimum angle value of the inclination angle of the thinning area includes:

[0019] The minimum angle value of the inclination angle of the thinning zone is determined based on the following expression:

[0020] θ min =arctan(H_thin / X_thin)

[0021] Wherein, H_thin is the parameter value of the height of the thinning area in the current round, and X_thin is the parameter value of the maximum thinning thickness in the current round.

[0022] In one embodiment, the first boundary constraint condition is pre-set based on a preset battery cell design capacity and N / P ratio.

[0023] In one embodiment, the target battery cell includes a negative electrode sheet, a separator and a current collector, the negative electrode sheet has a first surface and a second surface opposite to each other, the first surface faces the separator, and the second surface faces the current collector;

[0024] The determining whether a preset optimization condition is met according to the current round of potential simulation results and the current round of temperature simulation results includes:

[0025] Extracting the electric potential simulation data of the first surface and the electric potential simulation data of the second surface from the electric potential simulation results of the current round respectively;

[0026] Calculating the maximum negative electrode potential difference of the target battery cell according to the potential simulation data of the first surface and the potential simulation data of the second surface;

[0027] Calculating the maximum temperature difference of the target battery cell according to the temperature simulation result of the current round;

[0028] If the maximum negative electrode potential difference is less than the preset potential difference threshold, and the maximum temperature difference is less than the preset temperature difference threshold, it is determined that the preset optimization condition is met; otherwise, it is determined that the preset optimization condition is not met.

[0029] In one embodiment, the electrochemical-thermal coupling model of the target battery cell includes a thinning area model region, an overhang area model region and other model regions;

[0030] The simulation calculation is performed based on the electrochemical-thermal coupling model of the target battery cell, and the potential simulation result of the current round and the temperature simulation result of the current round are obtained, including:

[0031] Meshing the electrochemical-thermal coupling model of the target battery cell to obtain a meshing result; wherein the meshing density corresponding to the thinning area model region is greater than the meshing density corresponding to the remaining model regions, and the meshing density corresponding to the overhang area model region is greater than the meshing density corresponding to the remaining model regions;

[0032] A simulation calculation is performed according to the grid division result, and the potential simulation result of the current round and the temperature simulation result of the current round are obtained.

[0033] In a second aspect, some embodiments of the present application provide a device for determining the size of a thinning area, comprising:

[0034] A parameter value determination module, used to determine the parameter value of each thinning zone size parameter in the current round;

[0035] A model generation module, used to generate an electrochemical-thermal coupling model of a target battery cell according to the parameter values ​​of each of the thinning area size parameters in the current round; wherein the target battery cell is a battery cell designed based on the parameter values ​​of each of the thinning area size parameters in the current round;

[0036] A simulation calculation module, used to perform simulation calculation based on the electrochemical-thermal coupling model of the target battery cell, and obtain the potential simulation result of the current round and the temperature simulation result of the current round;

[0037] A judgment module, used to judge whether a preset optimization condition is met according to the potential simulation result of the current round and the temperature simulation result of the current round;

[0038] The parameter value output module is used to output the parameter value of each of the thinning area size parameters in the current round if the preset optimization condition is met, otherwise, enter the next round.

[0039] In a third aspect, an embodiment of the present application provides a storage medium storing computer-readable instructions. When the computer-readable instructions are executed by one or more processors, the one or more processors execute the steps of the method for determining the size of the thinning area described in any of the above embodiments.

[0040] In a fourth aspect, an embodiment of the present application provides a computer device, the computer device comprising: one or more processors, and a memory;

[0041] The memory stores computer-readable instructions, and when the computer-readable instructions are executed by the one or more processors, the steps of the method for determining the size of the thinning area described in any of the above embodiments are performed.

[0042] In the method, device and storage medium for determining the size of the thinning zone provided in some embodiments of the present application, the electrochemical-thermal coupling model simulation method can be used to accurately determine the potential distribution and temperature distribution of the battery cell under different thinning zone size designs, and the potential distribution and temperature distribution of the battery cell are used as the objective function to iteratively optimize the design of the thinning zone size parameters. In this way, the size of the thinning zone can be accurately determined without the need to mass-produce test cells, and is not affected by the test process parameters, thereby reducing the cost of trial and error, reducing testing resources and shortening the product development cycle, thereby reducing costs, improving efficiency and obtaining accurate thinning zone sizes. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] 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 or the description of the prior art 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 labor.

[0044] Figure 1 A schematic diagram of the three-dimensional structure of a square lithium battery cell in one embodiment;

[0045] Figure 2 for Figure 1 A side view of a square lithium battery cell is shown;

[0046] Figure 3 One of the flow charts of a method for determining the size of a thinning area in one embodiment;

[0047] Figure 4A A comparison diagram of a voltage simulation curve and a voltage test curve under 0.33C discharge in one embodiment;

[0048] Figure 4B A comparison diagram of a voltage simulation curve and a voltage test curve under 1C discharge in one embodiment;

[0049] Figure 4C is a comparison diagram of a voltage simulation curve and a voltage test curve under 3C discharge in one embodiment;

[0050] Figure 5 A schematic diagram of setting the inclination angle of the thinning area in one embodiment;

[0051] Fig. 6A In one embodiment, the electrode potential field of the negative electrode plate after charging is completed;

[0052] Figure 6B for Fig. 6A The potential simulation result of the second surface in the electrode potential field shown;

[0053] Figure 6C for Fig. 6A The potential simulation result of the first surface in the electrode potential field shown;

[0054] Fig. 7A In one embodiment, the temperature field of the negative electrode plate after charging is completed;

[0055] Figure 7B for Fig. 7A The temperature simulation results of the negative electrode in the temperature field shown;

[0056] Figure 7C for Fig. 7A The temperature simulation results of the positive electrode in the temperature field shown;

[0057] Figure 8 FIG2 is a second flow chart of a method for determining the size of a thinning area in an embodiment;

[0058] Fig. 9 is a schematic structural diagram of a device for determining the size of a thinning area in one embodiment;

[0059] Fig.10 FIG. 1 is a diagram of the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0060] 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.

[0061] The method for determining the size of the thinned area provided in some embodiments of the present invention can be used to determine the size of the thinned area of ​​a battery cell. The thinned area can be an area in the battery cell pole piece where the coating thickness of the coating is thinner. In other words, in the same battery cell pole piece, the coating thickness corresponding to the thinned area is thinner than that of other areas.

[0062] It can be understood that the method for determining the size of the thinning area provided in this article can be applied to any type, structure and shape of battery cells to determine the size of the thinning area corresponding to the battery cell. For ease of description, some embodiments below are described by taking the determination of the size of the thinning area of ​​a square lithium battery cell as an example.

[0063] See also Figure 1 , the square lithium battery cell may include a negative electrode ear 101, a positive electrode ear 102, a negative electrode current collector 103, a positive electrode current collector 104, a negative electrode plate, a positive electrode plate and a separator 109. Among them, the negative electrode plate may include a negative electrode thinning area 105, a negative electrode coating area 107 and a negative electrode thinning area separator 110, and the positive electrode plate may include a positive electrode thinning area 106, a positive electrode coating area 108 and a positive electrode thinning area separator 111. Compared with the positive electrode coating area, the positive electrode thinning area is coated with a thinner coating. Similarly, compared with the negative electrode coating area, the negative electrode thinning area is coated with a thinner coating.

[0064] Figure 1 In the figure, the x direction is the length direction of the battery cell, the y direction is the height direction of the battery cell, and the z direction is the thickness direction of the battery cell. The side view of the square lithium battery cell along the +x direction can be as follows: Figure 2As shown, the symbols and meanings of the parameters can be shown in Table 1:

[0065] Table 1

[0066]

[0067]

[0068] The following will be combined Figure 1 and Figure 2 The battery cell structure shown is used to describe the solution of the present application.

[0069] In one embodiment, the present application provides a method for determining the size of a thinning area, and the following embodiments are described by taking the method applied to a computer device as an example. It can be understood that the computer device described herein can be a device with data processing and model simulation functions, and can be but not limited to a desktop computer, a laptop computer, a server, etc.

[0070] like Figure 3 As shown, the method for determining the size of the thinning area of ​​the present application may include the following steps:

[0071] S302: Determine the parameter values ​​of each thinning area size parameter in the current round.

[0072] The skived area size parameter may be a parameter used to describe the area shape, area size and / or coating thickness of the skived area. For example, the skived area size parameter may be any one or any combination of parameters such as the skived area height, the skived area length, the maximum skived thickness, the side view shape of the skived area, the overhang height, etc. Figure 1 and Figure 2 In the example shown, the skived area parameters may include the positive skived area height, the positive skived area inclination angle, the maximum skived thickness corresponding to the positive skived area, the negative skived area height, the negative skived area inclination angle, the maximum skived thickness corresponding to the negative skived area, and the overhang height. The overhang height may be Y_neg / pos_overhang.

[0073] Specifically, the present application can determine the value of the thinning area size parameter that can meet the actual needs through iterative calculation to complete the thinning area size design. In each round of iterative calculation, the computer device can first determine the parameter value of each thinning area size parameter in the current round. Since the thinning area size parameter can be used to describe the area shape, area size and / or coating thickness of the thinning area, when the specific parameter value corresponding to the thinning area size parameter has been determined, the area shape, area size and / or coating thickness of the thinning area have also been determined.

[0074] S304: Generate an electrochemical-thermal coupling model of the target battery cell according to the parameter values ​​of each thinning area size parameter in the current round.

[0075] Among them, the target cell refers to a battery cell designed based on the parameter values ​​of each thinning area size parameter in the current round (hereinafter referred to as the parameter value of the thinning area size parameter in the current round). That is, the target cell has a thinning area structure described by each current parameter value. It can be understood that when the parameter value of the thinning area size parameter is adjusted, the thinning area structure described by each parameter value is also adjusted accordingly, and the cell simulation model of the target cell also changes accordingly.

[0076] In this step, the computer device can generate a corresponding battery cell simulation model according to each current parameter value, and obtain an electrochemical-thermal coupling model of the target battery cell. It can be understood that the present application can use any method to generate the electrochemical-thermal coupling model of the target battery cell, and the present application can use any type of electrochemical-thermal coupling model as the electrochemical-thermal coupling model of the target battery cell, and the present application does not make specific restrictions on this.

[0077] S306: Perform simulation calculation based on the electrochemical-thermal coupling model of the target battery cell, and obtain the potential simulation result of the current round and the temperature simulation result of the current round.

[0078] Among them, the potential simulation result of the current round can be used to reflect the potential distribution of the target battery cell, and the temperature simulation result of the current round can be used to reflect the temperature distribution of the target battery cell.

[0079] In this step, after the electrochemical-thermal coupling model of the target battery cell is generated, simulation calculations can be performed based on the electrochemical-thermal coupling model of the target battery cell to determine the potential distribution and temperature distribution of the target battery cell in an actual application scenario.

[0080] S308: judging whether preset optimization conditions are met according to the current round of potential simulation results and the current round of temperature simulation results.

[0081] Among them, the preset optimization conditions can be used to determine whether the potential distribution and temperature distribution of the target battery cell meet the actual application requirements. The specific content of the preset optimization conditions can be determined based on the actual situation, and this article does not make specific restrictions on this.

[0082] S310: If satisfied, output the parameter values ​​of each thinning area size parameter in the current round, otherwise, proceed to the next round.

[0083] Specifically, based on the current round of potential simulation results and the current round of temperature simulation results, it can be determined whether the target battery cell of the current round can meet the actual application requirements. If the target battery cell of the current round can meet the actual application requirements, each current parameter value can be output and the iteration ends. If the target battery cell of the current round fails to meet the actual application requirements, the next round can be entered and S302 to S310 can be repeatedly executed.

[0084] This application can use the means of electrochemical-thermal coupling model simulation to accurately determine the potential distribution and temperature distribution of the battery cell under different thinning zone size designs, and use the potential distribution and temperature distribution of the battery cell as the objective function to iteratively optimize the thinning zone size parameters. In this way, the thinning zone size can be accurately determined without the need to mass-produce test cells, and is not affected by the test process parameters, thereby reducing the cost of trial and error, reducing testing resources, and shortening the product development cycle, thereby reducing costs, improving efficiency, and obtaining accurate thinning zone sizes.

[0085] During the charge and discharge process of the battery, polarization inside the cell will generate heat. This heat can include ohmic heat, polarization heat and reversible entropy heat. The total heat can be calculated by the expression Q = I*(U-OCV)+I*T*dU / dT. In the formula, Q is the sum of ohmic heat, polarization heat and reversible entropy heat, I is the battery current, U is the battery voltage, OCV is the open circuit voltage, and T is the battery temperature.

[0086] From the energy conservation equation Cp*m*dT / dt=λx*dT / dx+λy*dT / dy+λz*dT / dz+h*As*(T-T_sur)+Q, it can be seen that if the battery cell generates heat Q during operation, and the battery cell dissipates heat under the condition of ambient temperature T_sur and ambient convection heat transfer coefficient h, the heat Q generated by the battery cell will act on the battery cell, causing the battery cell temperature to rise, thereby affecting the dynamic behavior of the battery cell. In the previous formula, Cp is the specific heat capacity of the battery cell, m is the mass of the battery cell, λx is the thermal conductivity of the battery in the x direction, λy is the thermal conductivity of the battery in the y direction, λz is the thermal conductivity of the battery in the z direction, As is the surface area of ​​the battery, and t is time.

[0087] Specifically, when the temperature of the battery core rises, the electrochemical reaction rate at the interface of the battery particles increases, the diffusion coefficient inside the particles increases, and the conductivity of the electrolyte and the diffusion coefficient of the electrolyte increase. The relationship between these kinetic parameters and temperature is shown in the expression Rx(T)=Rx_ref*exp(-Ea / R*(1 / T-1 / T_ref)). In the formula, Rx(T) is a kinetic parameter, which can be but is not limited to the positive and negative electrode reaction rate constants, the diffusion coefficients inside the positive and negative electrode particles, the conductivity of the electrolyte, and the diffusion coefficient of the electrolyte. Rx_ref is the parameter value of the kinetic parameter at the reference temperature, Ea is the activation energy of the kinetic parameter at the reference temperature, R is the molar gas constant, and T_ref is the reference temperature (the value can be 298.15K).

[0088] The temperature rise leads to an increase in kinetic behavior, and the increase in kinetic behavior will affect the polarization inside the battery cell, thereby reducing heat generation. Therefore, in one embodiment, the present application can use a three-dimensional electrochemical-three-dimensional thermal coupling model to describe the interaction between heat generation and kinetic behavior inside the battery cell.

[0089] Compared with the traditional P2D (Pseudo-Two-Dimensions) model, the 3D electrochemical-3D thermal coupling model not only takes into account the unevenness of the thickness direction of the battery cell, but also takes into account the lithium precipitation caused by the current unevenness in the thinning area and the coating area caused by the tab design. In addition, the 3D electrochemical-3D thermal coupling model fully couples heat generation and battery dynamics in both directions, taking into account both the effect of heat generation of the battery cell on temperature changes and the effect of temperature changes on electrochemical dynamics. In this way, the accuracy of the simulation calculation results can be guaranteed.

[0090] Furthermore, the control equations of the 3D electrochemical-3D thermal coupling model may include solid / liquid phase charge conservation equations, solid / liquid phase material conservation equations, interface electrochemical reaction equations, and energy conservation equations, etc. The 3D electrochemical-3D thermal coupling model can intuitively display the distribution of electrochemical parameters such as concentration field, potential field, and current field inside the battery cell pole piece, making it easier for technicians to perform battery cell design and failure mechanism analysis more intuitively and effectively.

[0091] In one embodiment, the step of generating a three-dimensional electrochemical-three-dimensional thermal coupling model of the target battery cell according to the parameter values ​​of each thinning area size parameter in the current round may include:

[0092] Step A1: Generate a three-dimensional geometric model of the target battery cell according to the parameter values ​​of each thinning area size parameter in the current round.

[0093] Among them, the three-dimensional geometric model of the target battery cell can be used to reflect the three-dimensional geometric structure of the target battery cell. In one example, the parametric modeling idea can be adopted to parametrically model the thinning area size parameters in the geometry, and build a three-dimensional geometric model of the pole piece of a single battery cell unit. In each round, the computer equipment only needs to change the specific parameter values ​​of the thinning area parameters to achieve the purpose of geometric pole piece design, thereby improving the modeling efficiency and then the simulation efficiency.

[0094] Step A2: Generate an electrochemical-thermal coupling model of the target battery cell according to the three-dimensional geometric model, target kinetic parameter values, target thermodynamic parameter values ​​and target thermophysical property parameter values ​​of the target battery cell; wherein the target kinetic parameter values, target kinetic parameter values ​​and target thermophysical property parameter values ​​are obtained by calibrating the parameters of a pre-constructed pseudo two-dimensional electrochemical-three-dimensional thermal coupling model based on pre-acquired battery rate charge and discharge voltage data and temperature data.

[0095] In this step, after obtaining the three-dimensional geometric model of the target battery cell, the computer equipment can generate a three-dimensional electrochemical-three-dimensional thermal coupling model of the target battery cell according to the three-dimensional geometric model of the target battery cell, the pre-calibrated target kinetic parameter values, target thermodynamic parameter values ​​and target thermophysical property parameter values, so that the constructed three-dimensional electrochemical-three-dimensional thermal coupling model can accurately describe the internal heat generation and kinetic behavior of the target battery cell, thereby obtaining more accurate potential simulation results and temperature simulation results.

[0096] Among them, the target kinetic parameter values, target thermodynamic parameter values, and target thermophysical property parameter values ​​can be obtained by calibrating the P2D electrochemical-3D thermal coupling model. The specific calibration process can be: pre-acquire the battery rate charge and discharge voltage data and temperature data, and use the battery rate charge and discharge voltage data and temperature data to calibrate the P2D electrochemical-3D thermal coupling model to determine the specific parameter values ​​of the kinetic parameters, thermodynamic parameters, and thermophysical property parameters, and obtain the target kinetic parameter values, target thermodynamic parameter values, and target thermophysical property parameter values. For example, Figure 4A , Figure 4B and Figure 4C As shown in the figure, after completing the parameter calibration, the discharge curves at each rate are within the range of 10% to 90% SOC (State of Charge). Under 0.33C to 3C discharge, the error between the simulated voltage and the measured voltage can be within 30mV.

[0097] In one embodiment, each skived area dimension parameter includes skived area height, maximum skived thickness, skived area inclination angle and overhang height. The skived area inclination angle is used to reflect the linear change of the coating thickness corresponding to the skived area along the height direction of the battery cell.

[0098] In the present application, the step of determining the parameter values ​​of each thinning area size parameter in the current round may include:

[0099] If the cell capacity of the target cell is negatively correlated with the inclination angle of the thinning zone, and the current round is not the first round, the parameter value of at least one thinning zone size parameter is adjusted according to the preset first boundary constraint and the first adjustment strategy; wherein the first adjustment strategy is a strategy for preferentially adjusting the parameter values ​​of the thinning zone height, the maximum thinning thickness and / or the overhang height, and for adjusting the parameter value of the thinning zone inclination angle in an incremental manner.

[0100] The first boundary constraint condition may be used to constrain the parameter value range of the thinning zone size parameter.

[0101] Specifically, if Figure 5 As shown, the coating thickness corresponding to the thinned area can change linearly along the height direction of the battery cell, and the linear change can be reflected by the inclination angle of the thinned area. Figure 5 In the figure, the shaded part is the area that has been cut off, the blank area is the active material area, that is, the area coated with paint, and θ is the inclination angle of the thinned area.

[0102] by Figure 2 Taking θ_pos_thin and θ_neg_thin of as an example, when θ_pos_thin is less than 90°, the coating thickness corresponding to the positive electrode thinning area can change in a gradient along the height direction of the battery cell, and the closer to the tab, the smaller the coating thickness, and the farther away from the tab, the greater the coating thickness. Similarly, when θ_neg_thin is less than 90°, the coating thickness corresponding to the negative electrode thinning area can change in a gradient along the height direction of the battery cell, and the closer to the tab, the smaller the coating thickness. Conversely, the farther away from the tab, the greater the coating thickness.

[0103] There is a corresponding conversion relationship between the cell capacity and the inclination angle of the thinning area. For example, Figure 2 In the equation, the positive electrode capacity Q_pos and the negative electrode capacity Q_neg can be calculated based on the following expressions:

[0104] Q_pos=q_pos*rho_pos*Loading_pos*W_pos*(L_pos*(H_pos-H_pos_thin)+L_pos_thin*H_pos_thin+1 / 2*H_pos_thin^2 / tan(θ_pos_thin))

[0105] Q_neg=q_neg*rho_neg*Loading_neg*W_neg*(L_neg*(H_neg-H_neg_thin)+L_neg_thin*H_neg_thin+1 / 2*H_neg_thin^2 / tan(θ_neg_thin))

[0106] Wherein, q_pos is the gram capacity of the active material of the positive electrode sheet, rho_pos is the compaction density of the positive electrode sheet, Loading_pos is the mass fraction of the active material in the positive electrode sheet, W_pos is the width of the positive electrode sheet, q_neg is the gram capacity of the active material of the negative electrode sheet, rho_neg is the compaction density of the negative electrode sheet, Loading_neg is the mass fraction of the active material in the negative electrode sheet, and W_neg is the width of the negative electrode sheet.

[0107] Taking the positive electrode capacity as an example, since the material area capacity is basically the same, the positive electrode capacity is mainly affected by the positive electrode thinning area capacity, and the positive electrode thinning area capacity can be calculated by the expression q_pos*rho_pos*Loading_pos*W_pos*1 / 2*H_pos_thin^2 / tan(θ_pos_thin). Considering that q_pos, rho_pos, Loading_pos, and W_pos are all pre-designed fixed values, the main parameters affecting the positive electrode thinning area capacity are H_pos_thin and θ_pos_thin, and the larger θ_pos_thin is, the smaller Q_pos is. In other words, the capacitance is negatively correlated with the inclination angle of the thinning area.

[0108] In this case, during the iterative calculation process, the computer device may give priority to adjusting the parameter values ​​of other thinning area size parameters except the thinning area inclination angle, and determine whether the target battery cell can meet the preset optimization conditions when adjusting the parameter values ​​of other thinning area size parameters. If adjusting other thinning area size parameters cannot make the target battery cell meet the preset optimization conditions, the thinning area inclination angle may be adjusted in an incremental manner. In this way, the battery cell capacity can be increased as much as possible while meeting the potential distribution requirements and temperature distribution requirements.

[0109] In one embodiment, the first boundary constraint condition is pre-set based on a preset battery cell design capacity and N / P ratio.

[0110] Specifically, in the actual manufacturing process, the average capacity of the battery cell can fluctuate within the range of tolerance. When the values ​​of the thinning area size parameters are different, the capacity of the battery cell will also change, but the changed battery cell capacity should fall within the range of tolerance.

[0111] It can be understood that the range of the average capacity of the battery cell can be determined according to the actual situation, and this article does not make specific restrictions on this. For the convenience of description, this article uses (1+1.2%)*Q_pos_avg as the maximum positive electrode capacity and (1-1.2%)*Q_pos_avg as the minimum positive electrode capacity for illustration. Among them, Q_pos_avg is the battery cell design capacity, which can be preset.

[0112] When ensuring the uniform coating thickness of the material area, the positive electrode thinning area size parameter can determine the value range based on the positive electrode capacity to obtain the first boundary constraint condition. Considering that the positive electrode capacity is mainly affected by the positive electrode thinning area capacity, the first boundary constraint condition can be generated as follows:

[0113] -1.2%*Q_pos_avg <q_pos*rho_pos*Loading_pos*W_pos*1 / 2*H_pos_thin^2 / tan(θ_pos_thin)<+1.2%*Q_pos_avg

[0114] Furthermore, considering that q_pos, rho_pos, Loading_pos, and W_pos are all fixed values, the value range of 1 / 2*H_pos_thin^2 / tan(θ_pos_thin) can be determined according to the above first boundary constraint condition, and then the value range of H_pos_thin and the value range of θ_pos_thin can be determined respectively.

[0115] In battery design, the ratio between the positive electrode capacity and the negative electrode capacity (i.e., the N / P ratio) is one of the battery design parameters and can be predetermined. Therefore, the capacity range of the negative electrode capacity can be determined based on the positive electrode capacity and the preset N / P ratio, and the value range corresponding to the negative electrode thinning area size parameter can be determined by combining the calculation expression of the negative electrode capacity and the capacity range of the negative electrode capacity, and this is used as the constraint boundary condition for parameter optimization.

[0116] In this way, comprehensive consideration can be made based on the battery cell design capacity and the N / P ratio, so as to achieve the battery cell design capacity while ensuring the size of the thinned area where local lithium deposition does not occur.

[0117] In one embodiment, determining the parameter values ​​of each thinning area size parameter in the current round also includes: if the battery cell capacity is negatively correlated with the thinning area inclination angle, and the current round is the first round, determining the minimum angle value of the thinning area inclination angle, and using the minimum angle value as the parameter value of the thinning area inclination angle in the current round.

[0118] Specifically, in order to achieve the maximum capacity design, when the cell capacity is negatively correlated with the inclination angle of the thinning area, the present application can give priority to setting the inclination angle of the thinning area to the minimum angle value, and give priority to adjusting the parameter values ​​of other thinning area size parameters except the inclination angle of the thinning area. If changing the parameter values ​​of other thinning area size parameters cannot make the target cell meet the preset optimization conditions, then increase the angle of the inclination angle of the thinning area. In this way, compared with the solution of completely removing the thinning area, the gradient thinning area design can increase the cell capacity.

[0119] In one embodiment, determining the minimum angle value of the thinning zone inclination angle includes:

[0120] The minimum angle value of the thinning zone inclination angle is determined based on the following expression:

[0121] θ min =arctan(H_thin / X_thin)

[0122] Where H_thin is the parameter value of the height of the thinning area in the current round, and X_thin is the parameter value of the maximum thinning thickness in the current round.

[0123] In this embodiment, the minimum angle value of the thinning area inclination angle is arctan(H_thin / X_thin), so that at least 1 / 2 of the thinning area can be retained. On the one hand, the capacity can be maximized, and on the other hand, the occurrence of electrode cracking caused by the tension of the thinning area during the electrode coating process can be reduced.

[0124] In one embodiment, Figure 1 and Figure 2 As shown, the target battery cell may include a negative electrode sheet, a separator and a current collector, wherein the negative electrode sheet has a first surface and a second surface facing each other, wherein the first surface faces the separator and the second surface faces the current collector. Fig. 6A , Figure 6B and Figure 6C As shown, the temperature simulation results of the target battery cell can be Fig. 7A , Figure 7B and Figure 7C shown.

[0125] According to the current round of potential simulation results and the current round of temperature simulation results, determine whether the preset optimization conditions are met, including:

[0126] In the electric potential simulation results of the current round, the electric potential simulation data of the first surface and the electric potential simulation data of the second surface are respectively extracted;

[0127] Calculating the maximum negative electrode potential difference of the target battery cell according to the potential simulation data of the first surface and the potential simulation data of the second surface;

[0128] According to the temperature simulation results of the current round, calculate the maximum temperature difference of the target battery cell;

[0129] If the maximum negative electrode potential difference is less than the preset potential difference threshold, and the maximum temperature difference is less than the preset temperature difference threshold, it is determined that the preset optimization condition is met, otherwise, it is determined that the preset optimization condition is not met.

[0130] In this embodiment, the potential distribution uniformity of the negative electrode sheet and the temperature difference of the battery cell are used as optimization targets, and whether the various parameter values ​​of the current round are the optimal parameter values ​​is determined accordingly. Specifically, the present application can monitor the potential simulation data of the first surface and the potential simulation data of the second surface of the negative electrode sheet, and calculate the maximum potential difference of the negative electrode sheet based on the potential simulation data of the first surface and the potential simulation data of the second surface to obtain the maximum negative electrode potential difference. This embodiment can also calculate the maximum temperature difference of the target potential based on the temperature simulation results of the current round.

[0131] If the maximum cathode potential difference of the current round is less than the preset potential difference threshold, and the maximum temperature difference of the current round is less than the preset temperature difference threshold, it can be determined that the preset optimization conditions are met, and each current parameter value can be output as the optimal design parameter. If the maximum cathode potential difference of the current round is greater than or equal to the preset potential difference threshold, or the maximum temperature difference of the current round is greater than or equal to the preset temperature difference threshold, it can be determined that the preset optimization conditions are not met and the next round can be entered.

[0132] It is understood that the specific values ​​of the preset potential difference threshold and the preset temperature difference threshold can be determined according to actual conditions, and this document does not impose any specific restrictions on this. In one example, the preset potential difference threshold can be 1 mV, and the preset temperature difference threshold can be 0.5°C.

[0133] In one embodiment, Figure 1 and Figure 2 As shown, the electrochemical-thermal coupling model of the target battery cell includes a thinning area model region, an overhang area model region and other model regions. Among them, the thinning area model region refers to the area corresponding to the thinning area of ​​the target battery cell in the electrochemical-thermal coupling model, the overhang area model region refers to the area corresponding to the overhang of the target battery cell in the electrochemical-thermal coupling model, and the other model regions refer to other model regions in the electrochemical-thermal coupling model except the thinning area model region and the overhang area model region.

[0134] Perform simulation calculations based on the electrochemical-thermal coupling model of the target battery cell, and obtain the current round of potential simulation results and the current round of temperature simulation results, including:

[0135] The electrochemical-thermal coupling model of the target battery cell is meshed to obtain meshing results; wherein, the meshing density corresponding to the thinning area model region is greater than the meshing density corresponding to the other model regions, and the meshing density corresponding to the overhang area model region is greater than the meshing density corresponding to the other model regions;

[0136] The simulation calculation is performed according to the grid division results, and the potential simulation results of the current round and the temperature simulation results of the current round are obtained.

[0137] In this embodiment, the simulation calculation can be performed by using a regional mesh division method, and the meshes in the thinning area model area and the overhang area model area are refined, and the finite element simulation calculation is performed accordingly. In this way, the model convergence can be accelerated and the simulation efficiency can be improved.

[0138] To facilitate understanding of the solution of this application, a specific example is provided below for illustration. Figure 8 As shown, the method for determining the size of the thinning area of ​​the present application may include the following steps:

[0139] S802: Obtaining initial cell parameter values, initial thermodynamic parameter values, initial kinetic parameter values, initial thermophysical property parameter values, battery rate charge and discharge voltage data, and temperature data.

[0140] S804: Generate a P2D electrochemical-3D thermal coupling model according to the initial cell parameter values, the initial thermodynamic parameter values, the initial kinetic parameter values, and the initial thermophysical property parameter values.

[0141] S806: Using the battery rate charge and discharge voltage data and temperature data, the P2D electrochemical-3D thermal coupling model is calibrated to obtain target thermodynamic parameter values, target kinetic parameter values, and target thermophysical property parameter values.

[0142] S808: Determine the parameter values ​​of each thinning zone size parameter in the current round respectively; wherein the thinning zone size parameters may include the positive thinning zone height, the positive thinning zone inclination angle, the maximum thinning thickness corresponding to the positive thinning zone, the negative thinning zone height, the negative thinning zone inclination angle, the maximum thinning thickness corresponding to the negative thinning zone and the overhang height.

[0143] Furthermore, if the current round is the first round, the size parameters of each thinning zone can be determined as initial values, and the inclination angle of the positive thinning zone and the inclination angle of the negative thinning zone can be set to the minimum angle value, as shown in Table 2.

[0144] Table 2

[0145]

[0146] If the current round is not the first round, the parameter values ​​of each thinning zone size parameter in the current round can be determined according to the value ranges of each thinning zone size parameter shown in Table 3. Specifically, when performing parameterized optimization, while satisfying the uniformity of the negative electrode potential and temperature uniformity, in order to achieve the design of maximizing capacity, when determining the inclination angle of the positive thinning zone and the inclination angle of the negative thinning zone, the minimum angle value arctan(H_pos_thin / X_pos_thin) corresponding to the inclination angle of the positive thinning zone can be used as the parameter value of the inclination angle of the positive thinning zone, and the minimum angle value arctan(H_neg_thin / X_neg_thin) corresponding to the inclination angle of the negative thinning zone can be used as the parameter value of the inclination angle of the negative thinning zone. In this example, the optimization weights of θ_neg_thin and θ_pos_thin can be reduced so that the computer equipment gives priority to changing the parameter values ​​of other thinning zone parameters to maximize the capacity of the battery cell.

[0147] Table 3

[0148]

[0149] S810: Generate a three-dimensional geometric model of the target battery cell based on parameter values ​​of each thinning area size parameter in the current round.

[0150] S812: Generate a three-dimensional electrochemical-three-dimensional thermal coupling model of the target battery cell according to the three-dimensional geometric model of the target battery cell.

[0151] S814: Simulate and calculate the three-dimensional electrochemical-three-dimensional thermal coupling model of the target battery cell, and obtain the potential simulation result of the first surface of the negative electrode piece, the potential simulation result of the second surface of the negative electrode piece, and the temperature simulation result of the target battery cell.

[0152] S816: Calculate the maximum negative electrode potential difference based on the potential simulation result of the first surface and the potential simulation result of the second surface, and calculate the maximum temperature difference of the target battery cell based on the temperature simulation result.

[0153] S818: Determine whether the maximum negative electrode potential difference is less than 1mv and whether the maximum temperature difference is less than 0.5°C. If so, proceed to S820; otherwise, proceed to S808.

[0154] S820: Outputting parameter values ​​of each thinning area size parameter in the current round. For example, the final parameter values ​​of each thinning area size parameter may be as shown in Table 4.

[0155] Table 4

[0156]

[0157] The following is a description of a device for determining the size of a thinning area provided in an embodiment of the present application. The device for determining the size of a thinning area described below and the method for determining the size of a thinning area described above can be referred to in correspondence with each other.

[0158] In one embodiment, Fig. 9 As shown, the present application provides a device 911 for determining the size of a thinning area, comprising:

[0159] A parameter value determination module 911 is used to determine the parameter value of each thinning area size parameter in the current round;

[0160] A model generation module 912, for generating an electrochemical-thermal coupling model of a target cell according to the parameter values ​​of each of the thinning area size parameters in the current round; wherein the target cell is a battery cell designed based on the parameter values ​​of each of the thinning area size parameters in the current round;

[0161] A simulation calculation module 913 is used to perform simulation calculation based on the electrochemical-thermal coupling model of the target battery cell, and obtain the potential simulation result of the current round and the temperature simulation result of the current round;

[0162] A judgment module 914 is used to judge whether a preset optimization condition is met according to the current round of potential simulation results and the current round of temperature simulation results;

[0163] The parameter value output module 915 is used to output the parameter value of each of the thinning area size parameters in the current round if the preset optimization condition is met, otherwise, enter the next round.

[0164] In one embodiment, the electrochemical-thermal coupling model of the target battery cell is a three-dimensional electrochemical-three-dimensional thermal coupling model.

[0165] In one embodiment, each of the thinning area size parameters includes the thinning area height, the maximum thinning thickness, the thinning area inclination angle and the overhang height, and the thinning area inclination angle is used to reflect the linear change of the coating thickness corresponding to the thinning area along the height direction of the battery cell. The parameter value determination module 911 of the present application includes:

[0166] A parameter adjustment unit is used to adjust the parameter value of at least one of the thinning area size parameters according to a preset first boundary constraint and a first adjustment strategy if the cell capacity of the target cell is negatively correlated with the inclination angle of the thinning area, and the current round is not the first round; wherein the first adjustment strategy is a strategy for preferentially adjusting the parameter values ​​of the thinning area height, the maximum thinning thickness and / or the overhang height, and for adjusting the parameter value of the thinning area inclination angle in an incremental manner.

[0167] In one embodiment, the parameter value determination module 911 of the present application further includes:

[0168] A parameter determination unit is used to determine the minimum angle value of the thinning zone inclination angle if the battery cell capacity is negatively correlated with the thinning zone inclination angle and the current round is the first round, and use the minimum angle value as the parameter value of the thinning zone inclination angle in the current round.

[0169] In one embodiment, the parameter determination unit of the present application includes:

[0170] The minimum angle value calculation unit is used to determine the minimum angle value of the inclination angle of the thinning area based on the following expression:

[0171] θ min =arctan(H_thin / X_thin)

[0172] Wherein, H_thin is the parameter value of the height of the thinning area in the current round, and X_thin is the parameter value of the maximum thinning thickness in the current round.

[0173] In one embodiment, the first boundary constraint condition is pre-set based on a preset battery cell design capacity and an N / P ratio.

[0174] In one embodiment, the target battery cell includes a negative electrode sheet, a separator and a current collector, the negative electrode sheet has a first surface and a second surface opposite to each other, the first surface faces the separator, and the second surface faces the current collector. The judgment module 914 of the present application includes:

[0175] A potential extraction unit, used to extract the potential simulation data of the first surface and the potential simulation data of the second surface from the potential simulation results of the current round respectively;

[0176] a maximum negative electrode potential difference calculation unit, configured to calculate the maximum negative electrode potential difference of the target battery cell according to the potential simulation data of the first surface and the potential simulation data of the second surface;

[0177] A maximum temperature difference calculation unit, used to calculate the maximum temperature difference of the target battery cell according to the temperature simulation result of the current round;

[0178] A judgment unit is used to determine that the preset optimization condition is met if the maximum negative electrode potential difference is less than a preset potential difference threshold and the maximum temperature difference is less than a preset temperature difference threshold, and otherwise, determine that the preset optimization condition is not met.

[0179] In one embodiment, the electrochemical-thermal coupling model of the target battery cell includes a thinning area model region, an overhang area model region and other model regions. The simulation calculation module 913 of the present application includes:

[0180] A mesh division unit, used for meshing the electrochemical-thermal coupling model of the target battery cell to obtain a mesh division result; wherein the mesh division density corresponding to the thinning area model region is greater than the mesh division density corresponding to the remaining model regions, and the mesh division density corresponding to the overhang area model region is greater than the mesh division density corresponding to the remaining model regions;

[0181] A simulation unit is used to perform simulation calculations according to the grid division results, and obtain the potential simulation results of the current round and the temperature simulation results of the current round.

[0182] In one embodiment, the present application further provides a storage medium storing computer-readable instructions. When the computer-readable instructions are executed by one or more processors, the one or more processors execute the steps of the method for determining the size of the thinning area in any embodiment.

[0183] In one embodiment, the present application further provides a computer device having computer-readable instructions stored therein. When the computer-readable instructions are executed by one or more processors, the one or more processors execute the steps of the method for determining the size of the thinning area in any embodiment.

[0184] Indicatively, Fig.10 The internal structure diagram of a computer device provided in an embodiment of the present application is shown in FIG. 1 . In one example, the computer device may be a server. Fig.10 The computer device 900 includes a processing component 902, which further includes one or more processors, and a memory resource represented by a memory 901 for storing instructions executable by the processing component 902, such as an application. The application stored in the memory 901 may include one or more modules, each corresponding to a set of instructions. In addition, the processing component 902 is configured to execute the instructions to perform the steps of the thinning area size determination method described in any of the above embodiments.

[0185] The computer device 900 may further include a power supply component 903 configured to perform power management of the computer device 900, a wired or wireless network interface 904 configured to connect the computer device 900 to a network, and an input / output (I / O) interface 905. The computer device 900 may operate based on an operating system stored in the memory 901, such as Windows Server TM, Mac OS X TM, Unix TM, Linux TM, Free BSD TM or the like.

[0186] Those skilled in the art will understand that the internal structure of the computer device shown in the present application is merely a block diagram of a partial structure related to the scheme of the present application, and does not constitute a limitation on the computer device to which the scheme of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0187] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the term "include", "comprise" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not clearly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. Herein, "one", "one", "said", "the" and "it" may also include plural forms, unless the context clearly indicates another way. A plurality refers to at least two cases, such as 2, 3, 5 or 8, etc. "And / or" includes any and all combinations of the relevant listed items.

[0188] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can refer to each other.

[0189] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for determining the size of a thinning area, characterized in that: include: Determine the parameter values ​​of each thinning zone size parameter in the current round; Generate an electrochemical-thermal coupling model of a target battery cell according to the parameter values ​​of each of the thinning area size parameters in the current round; wherein the target battery cell is a battery cell designed based on the parameter values ​​of each of the thinning area size parameters in the current round; Performing simulation calculation based on the electrochemical-thermal coupling model of the target battery cell, and obtaining the potential simulation result of the current round and the temperature simulation result of the current round; Determining whether a preset optimization condition is met according to the current round of potential simulation results and the current round of temperature simulation results; If satisfied, then the parameter values ​​of the various thinning area size parameters in the current round are output; otherwise, proceed to the next round.

2. The method according to claim 1, characterized in that The electrochemical-thermal coupling model of the target battery cell is a three-dimensional electrochemical-three-dimensional thermal coupling model.

3. The method according to claim 1, characterized in that Each of the thinning area size parameters includes the thinning area height, the maximum thinning thickness, the thinning area inclination angle and the overhang height, wherein the thinning area inclination angle is used to reflect the linear change of the coating thickness corresponding to the thinning area along the height direction of the battery cell; Determining the parameter values ​​of the size parameters of each thinning area in the current round includes: If the cell capacity of the target cell is negatively correlated with the inclination angle of the thinning zone, and the current round is not the first round, then according to the preset first boundary constraint condition and the first adjustment strategy, the parameter value of at least one of the thinning zone size parameters is adjusted; wherein the first adjustment strategy is a strategy for preferentially adjusting the parameter values ​​of the thinning zone height, the maximum thinning thickness and / or the overhang height, and adjusting the parameter value of the thinning zone inclination angle in an incremental manner.

4. The method according to claim 3, characterized in that The step of determining the parameter values ​​of the size parameters of each thinning area in the current round further includes: If the cell capacity is negatively correlated with the inclination angle of the thinning zone, and the current round is the first round, the minimum angle value of the inclination angle of the thinning zone is determined, and the minimum angle value is used as the parameter value of the inclination angle of the thinning zone in the current round.

5. The method according to claim 4, characterized in that Determining the minimum angle value of the inclination angle of the thinning area includes: The minimum angle value of the inclination angle of the thinning zone is determined based on the following expression: θ min =arctan(H_thin / X_thin) Wherein, H_thin is the parameter value of the height of the thinning area in the current round, and X_thin is the parameter value of the maximum thinning thickness in the current round.

6. The method according to any one of claims 3 to 5, characterized in that: The first boundary constraint condition is pre-set based on a preset battery cell design capacity and N / P ratio.

7. The method according to any one of claims 1 to 5, characterized in that: The target battery cell comprises a negative electrode sheet, a separator and a current collector, wherein the negative electrode sheet has a first surface and a second surface opposite to each other, wherein the first surface faces the separator and the second surface faces the current collector; The determining whether a preset optimization condition is met according to the current round of potential simulation results and the current round of temperature simulation results includes: Extracting the electric potential simulation data of the first surface and the electric potential simulation data of the second surface from the electric potential simulation results of the current round respectively; Calculating the maximum negative electrode potential difference of the target battery cell according to the potential simulation data of the first surface and the potential simulation data of the second surface; Calculating the maximum temperature difference of the target battery cell according to the temperature simulation result of the current round; If the maximum negative electrode potential difference is less than the preset potential difference threshold, and the maximum temperature difference is less than the preset temperature difference threshold, it is determined that the preset optimization condition is met; otherwise, it is determined that the preset optimization condition is not met.

8. The method according to any one of claims 1 to 5, characterized in that: The electrochemical-thermal coupling model of the target battery cell includes a thinning area model region, an overhang area model region and other model regions; The simulation calculation is performed based on the electrochemical-thermal coupling model of the target battery cell, and the potential simulation result of the current round and the temperature simulation result of the current round are obtained, including: Meshing the electrochemical-thermal coupling model of the target battery cell to obtain a meshing result; wherein the meshing density corresponding to the thinning area model region is greater than the meshing density corresponding to the remaining model regions, and the meshing density corresponding to the overhang area model region is greater than the meshing density corresponding to the remaining model regions; A simulation calculation is performed according to the grid division result, and the potential simulation result of the current round and the temperature simulation result of the current round are obtained.

9. A device for determining the size of a thinning area, characterized in that: include: A parameter value determination module, used to determine the parameter value of each thinning zone size parameter in the current round; A model generation module, used to generate an electrochemical-thermal coupling model of a target battery cell according to the parameter values ​​of each of the thinning area size parameters in the current round; wherein the target battery cell is a battery cell designed based on the parameter values ​​of each of the thinning area size parameters in the current round; A simulation calculation module, used to perform simulation calculation based on the electrochemical-thermal coupling model of the target battery cell, and obtain the potential simulation result of the current round and the temperature simulation result of the current round; A judgment module, used to judge whether a preset optimization condition is met according to the potential simulation result of the current round and the temperature simulation result of the current round; The parameter value output module is used to output the parameter value of each of the thinning area size parameters in the current round if the preset optimization condition is met, otherwise, enter the next round.

10. A storage medium, characterized in that: The storage medium stores computer-readable instructions, and when the computer-readable instructions are executed by one or more processors, the one or more processors execute the steps of the method for determining the size of the thinned area as claimed in any one of claims 1 to 8.

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