Reduced-order model electrochemical simulation method and device for multilayer coating

Abstract

The present application relates to a method and device for electrochemical simulation of a multi-layer coated reduced-order model, which belongs to the field of battery simulation technology. The method comprises: dividing the positive and negative electrodes of the simulation model of the multi-layer coated battery cell into a plurality of simulation regions, each simulation region corresponding one-to-one to the multi-layer coating of the battery cell; establishing a reduced-order model based on the regional simulation parameters corresponding to each simulation region to perform electrochemical simulation of the battery cell; solving the problem that the traditional reduced-order model cannot perform electrochemical simulation of the multi-layer coated battery cell; and realizing electrochemical simulation of the multi-layer coated battery cell based on the reduced-order model.

Description

Technical Field

[0001] The present application relates to a reduced-order model electrochemical simulation method and device for multi-layer coating, and belongs to the field of battery simulation technology. Background Art

[0002] The multilayer coating process for batteries involves applying one or more layers of slurry to a current collector. The coated electrode materials include essential battery materials such as active materials, conductive agents, and binders.

[0003] When performing electrochemical simulations on battery cells, it is necessary to simulate the coating of the cell. Traditional simulation methods include simulating the coating of the cell using reduced-order models, such as the single particle model (SPM) or pseudo-two-dimensional model (P2D).

[0004] However, both SPM and P2D can only perform electrochemical simulation on single-layer coated cells, but cannot perform electrochemical simulation on multi-layer coated cells. Summary of the Invention

[0005] This application provides a multi-layer coated reduced-order model electrochemical simulation method and device, which can realize electrochemical simulation of multi-layer coated battery cells based on the reduced-order model. This application provides the following technical solutions:

[0006] In a first aspect, a reduced-order model electrochemical simulation method for multilayer coating is provided, the method comprising:

[0007] Dividing the positive and negative electrodes of the simulation model of the multi-layer coated battery cell into a plurality of simulation regions, each simulation region corresponding to the multi-layer coating of the battery cell;

[0008] A reduced-order model is established based on regional simulation parameters corresponding to each simulation region to perform electrochemical simulation on the battery cell.

[0009] Optionally, the method further includes:

[0010] Multiple simulated active substances are set in each simulation area;

[0011] and / or,

[0012] A plurality of coating parameters of the coating corresponding to the simulation area are set for each simulation area.

[0013] Optionally, the plurality of simulated active substances include: a plurality of active substance particles, and / or a plurality of active substance particle sizes;

[0014] The plurality of coating parameters include: a plurality of coating porosities, a plurality of active material volume fractions, a conductive agent and a binder volume fraction, and / or tortuosity.

[0015] Optionally, establishing a reduced-order model based on regional simulation parameters corresponding to each simulation region to perform electrochemical simulation on the battery cell includes:

[0016] Determine the reaction current density in each simulation area, the sum of the reaction current densities being equal to the external circuit current of the battery cell;

[0017] Solving the diffusion equation within the active material particles in each simulation area to obtain the lithium ion concentration within the active material particles;

[0018] The source terms in the solid phase potential equation, liquid phase potential equation and electrolyte lithium ion concentration equation are modified from the reaction current density of active materials in one simulation area to the reaction current density of active materials in multiple simulation areas.

[0019] Optionally, the external circuit current is expressed by the following formula:

[0020] ;

[0021] ;

[0022] ;

[0023] Where i represents the i-th layer of coating, dx is the length element in the thickness direction of the battery cell, represents the integral within the i-layer coating area, is the reaction current density of each active substance in the i-th coating layer, F is the Faraday constant, is the reaction rate constant of each active substance in the i-th coating layer, is the lithium ion concentration of the electrolyte, is the reference electrolyte lithium ion concentration, is the transfer coefficient, is the maximum lithium ion concentration of the active material in the i-th coating layer, is the lithium ion concentration on the surface of the active material particles in the i-th coating layer, R is the ideal gas constant, T is the temperature, is the overvoltage, where is the solid phase potential, is the liquid phase potential, is the equilibrium potential of the active materials in each layer; is the radius of the active material particle in the i-th coating layer, is the volume fraction of active material particles in the i-th coating layer, is the specific surface area of ​​the active material particles in the i-th coating layer.

[0024] Optionally, the source terms in the solid-phase potential equation and the liquid-phase potential equation are: the reaction current density of the active material particles in the simulation area corresponding to the i-th layer of coating ;

[0025] The source term of the liquid phase lithium ion concentration diffusion equation is: the reaction current density of the active material particles in the simulation area corresponding to the i-th layer of coating corresponding lithium ion flux;

[0026] Set the boundary flux to the reaction current density of the active material particles in the simulation area corresponding to the i-th layer of coating , based on the boundary flux, the solid-phase lithium ion diffusion equation is solved in the active material particle sub-region within the simulation region corresponding to the i-th coating layer.

[0027] In a second aspect, a multi-layer coated reduced-order model electrochemical simulation device is provided, the device comprising:

[0028] A region division module is used to divide the positive and negative electrodes of the simulation model of the multi-layer coated battery cell into multiple simulation regions, each simulation region corresponding to the multi-layer coating of the battery cell;

[0029] The electrochemical simulation module is used to establish a reduced-order model based on regional simulation parameters corresponding to each simulation region to perform electrochemical simulation on the battery cell.

[0030] Optionally, the device further comprises:

[0031] A first setting module is used to set a plurality of simulated active substances in each simulation area;

[0032] and / or,

[0033] The second setting module is used to set, for each simulation area, a plurality of coating parameters of the coating corresponding to the simulation area.

[0034] Optionally, the plurality of simulated active substances include: a plurality of active substance particles, and / or a plurality of active substance particle sizes;

[0035] The plurality of coating parameters include: a plurality of coating porosities, a plurality of active material volume fractions, a conductive agent and a binder volume fraction, and / or tortuosity.

[0036] Optionally, the electrochemical simulation module is used to:

[0037] Determine the reaction current density in each simulation area, the sum of the reaction current densities being equal to the external circuit current of the battery cell;

[0038] Solving the diffusion equation within the active material particles in each simulation area to obtain the lithium ion concentration within the active material particles;

[0039] The source terms in the solid phase potential equation, liquid phase potential equation and electrolyte lithium ion concentration equation are modified from the reaction current density of active materials in one simulation area to the reaction current density of active materials in multiple simulation areas.

[0040] In a third aspect, a device for electrochemical simulation of a reduced-order model of multilayer coating is provided, the device comprising a processor and a memory; a program is stored in the memory, and the program is loaded and executed by the processor to implement the electrochemical simulation method of the reduced-order model of multilayer coating described in the first aspect.

[0041] In a fourth aspect, a computer-readable storage medium is provided, wherein a program is stored in the storage medium, and the program is loaded and executed by the processor to implement the reduced-order model electrochemical simulation method of multilayer coating described in the first aspect.

[0042] The beneficial effects of the present application are: by dividing the positive and negative electrodes of the simulation model of the multi-layer coated battery cell into multiple simulation areas respectively, each simulation area corresponds one-to-one to the multi-layer coating of the battery cell; a reduced-order model is established based on the regional simulation parameters corresponding to each simulation area to perform electrochemical simulation of the battery cell; it can solve the problem that the traditional reduced-order model cannot perform electrochemical simulation of the multi-layer coated battery cell; and realize the electrochemical simulation of the multi-layer coated battery cell based on the reduced-order model.

[0043] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application and to implement it in accordance with the contents of the specification, the following is a detailed description of the preferred embodiments of the present application in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a flow chart of a reduced-order model electrochemical simulation method for multilayer coating provided by one embodiment of the present application;

[0045] Figure 2 This is a block diagram of a reduced-order model electrochemical simulation device for multi-layer coating provided in one embodiment of the present application. DETAILED DESCRIPTION

[0046] The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0047] Figure 1This is a flow chart of a reduced-order model electrochemical simulation method for multilayer coatings provided in one embodiment of the present application. This embodiment illustrates the method using an electronic device as an example. The electronic device may be a user terminal or server with computing capabilities. This embodiment does not limit the implementation of the electronic device. The method includes at least the following steps:

[0048] Step 101 : dividing the positive and negative electrodes of the simulation model of the multi-layer coated battery cell into a plurality of simulation regions, respectively. Each simulation region corresponds to the multi-layer coating of the battery cell.

[0049] The traditional single particle model and quasi-two-dimensional model divide the simulation model of the battery cell into one region each in the positive and negative electrodes, and the material, particle size, volume fraction of the active material, and porosity of the coating in this region are all the same. At this time, the traditional single particle model and quasi-two-dimensional model can only perform electrochemical simulation on battery cells with a single layer of coating. In this embodiment, by dividing the positive and negative electrodes into multiple simulation regions based on the multi-layer coating of the battery cell, each simulation region can simulate the electrochemical characteristics of a layer of coating, and electrochemical simulation of battery cells with multi-layer coatings can be achieved.

[0050] Optionally, in this embodiment, a plurality of simulated active substances may be set in each simulation area; and / or a plurality of coating parameters of the coating corresponding to the simulation area may be set for each simulation area.

[0051] In one example, the multiple simulated active materials include: multiple active material particles, multiple active material particle sizes; the multiple coating parameters include but are not limited to: multiple coating porosities, multiple active material volume fractions, conductive agent and binder volume fractions, and / or tortuosity, etc. This embodiment does not limit the content of the coating parameters.

[0052] Step 102 : establishing a reduced-order model based on regional simulation parameters corresponding to each simulation region to perform electrochemical simulation on the battery cell.

[0053] In one example, a reduced-order model is established based on the regional simulation parameters corresponding to each simulation area to perform electrochemical simulation of the battery cell, including: determining the reaction current density in each simulation area, the sum of the reaction current densities is equal to the external circuit current of the battery cell; solving the diffusion equation in the active material particles in each simulation area to obtain the lithium ion concentration in the active material particles; and modifying the source terms in the solid phase potential equation, the liquid phase potential equation, and the electrolyte lithium ion concentration equation from the reaction current density of the active material in one simulation area to the reaction current density of the active material in multiple simulation areas.

[0054] The external circuit current is expressed by the following formula:

[0055] ;

[0056] ;

[0057] ;

[0058] Where i represents the i-th layer of coating, dx is the length element in the thickness direction of the battery cell, represents the integral within the i-layer coating area, is the reaction current density of each active substance in the i-th coating layer, F is the Faraday constant, is the reaction rate constant of each active substance in the i-th coating layer, is the lithium ion concentration of the electrolyte, is the reference electrolyte lithium ion concentration, is the transfer coefficient, schematically, In other embodiments, and The value of can also be other values. This embodiment is not correct. and The value of is limited. is the maximum lithium ion concentration of the active material in the i-th coating layer, is the lithium ion concentration on the surface of the active material particles in the i-th coating layer, obtained by solving the solid-phase lithium ion diffusion equation. R is the ideal gas constant. T is the temperature, obtained by solving the heat transfer equation. is the overvoltage, where is the solid phase potential and is obtained by solving the solid phase potential equation. is the liquid potential, which is obtained by solving the liquid potential equation. is the equilibrium potential of the active materials in each layer; is the radius of the active material particle in the i-th coating layer, is the volume fraction of active material particles in the i-th coating layer, is the specific surface area of ​​the active material particles in the i-th coating layer. 、 、 、 Preset input data for external circuit current.

[0059] Among them, the liquid phase lithium ion diffusion equation is: .in, is the liquid phase lithium ion concentration, For time, is the liquid phase lithium ion diffusion coefficient, is the ion mobility number, is the Faraday constant, is the reaction current density, is the specific surface area. Solid-phase lithium ion diffusion equation: .in, is the solid phase lithium ion concentration, For time, is the solid phase lithium ion diffusion coefficient. Solid phase potential equation: .in, is the solid phase potential, is the solid phase conductivity. Liquid phase potential equation: .in, is the liquid phase potential, is the liquid conductivity, R is the ideal gas constant, T is the temperature, is the activity coefficient correction factor, usually set to 1. When solving, the parameters corresponding to each region are used in each region. Only the source term in the equation needs to be determined during the solution process, and the remaining parameters are input values. The solution method is the conventional method for solving partial differential equations.

[0060] Schematically, the source terms in the solid-phase potential equation and the liquid-phase potential equation are: the reaction current density of the active material particles in the simulation area corresponding to the i-th layer of coating The source term of the liquid phase lithium ion concentration diffusion equation is: the reaction current density of the active material particles in the simulation area corresponding to the i-th layer of coating The corresponding lithium ion flux; set the boundary flux to the reaction current density of the active material particles in the simulation area corresponding to the i-th layer of coating , based on the boundary flux, the solid-phase lithium ion diffusion equation is solved in the active material particle sub-region within the simulation region corresponding to the i-th layer of coating.

[0061] To sum up, the electrochemical simulation method of the reduced-order model of the multi-layer coating provided in this embodiment divides the positive and negative electrodes of the simulation model of the multi-layer coated battery cell into multiple simulation areas respectively, and each simulation area corresponds one-to-one to the multi-layer coating of the battery cell; a reduced-order model is established based on the regional simulation parameters corresponding to each simulation area to perform electrochemical simulation of the battery cell; it can solve the problem that the traditional reduced-order model cannot perform electrochemical simulation of the multi-layer coated battery cell; and realize the electrochemical simulation of the multi-layer coated battery cell based on the reduced-order model.

[0062] In order to more clearly understand the reduced-order model electrochemical simulation method for multilayer coating, two examples are given below to illustrate the method.

[0063] In one example, it is assumed that two layers of active material particles of different materials are coated in the positive electrode of the simulation model. Specifically, the positive electrode is coated with two layers, lithium iron phosphate (LFP) is coated near the current collector side, and ternary lithium (NCM) is coated near the separator side. Assuming that the two layers of coating have the same thickness, the radius of the NCM particles is 5 microns, the radius of the LFP particles is 0.5 microns, the volume fraction of NCM is 0.48, and the volume fraction of LFP is also 0.48. The simulation area corresponding to each layer of coating in the thickness direction of the positive electrode is divided into 10 grids, and a sub-region of the active material particles in the corresponding coating is set on each grid, representing the NCM particles and LFP particles in the two layers respectively, and the geometric size of each sub-region is set to the size of the corresponding particle.

[0064] During the solution process, ensure Satisfy the external circuit current equation

[0065] ;

[0066] Here, i represents the i-th coating layer.

[0067] ;

[0068] ;

[0069] In the positive electrode region, the source terms in the solid phase potential equation and the liquid phase potential equation are the reaction current density of the active material particles in the corresponding regions. In the positive electrode region, the source terms of the liquid phase lithium ion diffusion equation in the two regions are the reaction current density of the corresponding active material particles The corresponding lithium ion flux. The solid phase lithium ion diffusion equation is solved in the active material particle sub-region within the two regions, and the boundary flux is the reaction current density of the corresponding active material particle. . Solve all electrochemical equations.

[0070] In another example, assume that the two layers in the positive electrode are coated with the same material, and the porosity of the two layers is different. Specifically, the positive electrode active material is selected to be coated with two layers of ternary lithium (NCM). The porosity of the coating close to the current collector side is smaller, which is 25%, and the porosity of the coating close to the separator side is larger, which is 30%. The two coating layers are of the same thickness, and the radius of the NCM particles is 5 microns, and the volume fraction is 0.48. The simulation area corresponding to each layer of coating in the thickness direction of the positive electrode is divided into 10 grids, and an active material particle sub-region is set on each grid to represent the NCM particles in the two layers. The geometric size of each sub-region is set to the size of the corresponding particle.

[0071] During the solution process, ensure Satisfy the external circuit current equation

[0072] ;

[0073] Here, i represents the i-th coating layer.

[0074] ;

[0075] When solving the liquid potential equation and the liquid lithium ion diffusion equation, the porosity in the two coating regions of the positive electrode is set to the corresponding values. All electrochemical equations are solved.

[0076] Figure 2 1 is a block diagram of a reduced-order model electrochemical simulation device for multi-layer coatings provided in one embodiment of the present application. The device includes at least the following modules: a region division module 210 and an electrochemical simulation module 220.

[0077] A region division module 210 is used to divide the positive and negative electrodes of the simulation model of the multi-layer coated battery cell into a plurality of simulation regions, each simulation region corresponding to the multi-layer coating of the battery cell;

[0078] The electrochemical simulation module 220 is used to establish a reduced-order model based on regional simulation parameters corresponding to each simulation region, so as to perform electrochemical simulation on the battery cell.

[0079] Optionally, the device further comprises: a first setting module for setting a plurality of simulated active substances in each simulation area; and / or a second setting module for setting a plurality of coating parameters of the coating corresponding to the simulation area for each simulation area.

[0080] Optionally, the multiple simulated active materials include: multiple active material particles, and / or multiple active material particle sizes; the multiple coating parameters include: multiple coating porosities, multiple active material volume fractions, conductive agent and binder volume fractions, and / or tortuosity.

[0081] For relevant details, please refer to the above method embodiment.

[0082] It should be noted that: the multi-layer coating reduced-order model electrochemical simulation device provided in the above embodiment only uses the division of the above-mentioned functional modules as an example when performing multi-layer coating reduced-order model electrochemical simulation. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the multi-layer coating reduced-order model electrochemical simulation device can be divided into different functional modules to complete all or part of the functions described above. In addition, the multi-layer coating reduced-order model electrochemical simulation device provided in the above embodiment and the multi-layer coating reduced-order model electrochemical simulation method embodiment belong to the same concept. The specific implementation process is detailed in the method embodiment and will not be repeated here.

[0083] Optionally, the present application also provides a computer-readable storage medium, in which a program is stored, and the program is loaded and executed by a processor to implement the reduced-order model electrochemical simulation method of multilayer coating of the above method embodiment.

[0084] Optionally, the present application also provides a computer product comprising a computer-readable storage medium storing a program, wherein the program is loaded and executed by a processor to implement the reduced-order model electrochemical simulation method for multilayer coating of the above-mentioned method embodiment.

[0085] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0086] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A reduced-order model electrochemical simulation method for multilayer coating, characterized in that: The method comprises: Dividing the positive and negative electrodes of the simulation model of the multi-layer coated battery cell into a plurality of simulation regions, each simulation region corresponding to the multi-layer coating of the battery cell; Establishing a reduced-order model based on regional simulation parameters corresponding to each simulation region to perform electrochemical simulation on the battery cell, including: determining a reaction current density in each simulation region, wherein the sum of the reaction current densities is equal to the external circuit current of the battery cell; solving a diffusion equation within the active material particles within each simulation region to obtain a lithium ion concentration within the active material particles; and modifying source terms in a solid phase potential equation, a liquid phase potential equation, and an electrolyte lithium ion concentration equation from the reaction current density of the active material within one simulation region to the reaction current density of the active material within multiple simulation regions; The external circuit current is expressed by the following formula: Where i represents the i-th layer of coating, dx is the length element in the thickness direction of the battery cell, It represents the integral within the i-layer coating area, J i is the reaction current density of each active substance in the i-th layer of coating, F is the Faraday constant, k i is the reaction rate constant of each active substance in the i-th coating layer, c l is the lithium ion concentration of the electrolyte, c l,ref is the lithium ion concentration of the reference electrolyte, α a +α c =1 is the transfer coefficient, c s,max,i is the maximum lithium ion concentration of the active material in the i-th coating layer, c s,surf,i is the lithium ion concentration on the surface of the active material particles in the i-th coating layer, R is the ideal gas constant, T is the temperature, η i =φ s -φ l -E eq,i is the overvoltage, where φ s is the solid phase potential, φ l is the liquid phase potential, E eq,i is the equilibrium potential of the active material in each layer; r i is the radius of the active material particle in the i-th coating layer, ε s,i is the volume fraction of active material particles in the i-th coating layer, β i is the specific surface area of ​​the active material particles in the i-th coating layer; Also includes: A plurality of simulated active substances are provided in each simulation area; the plurality of simulated active substances include: a plurality of active substance particles, and / or a plurality of active substance particle sizes; and / or, Setting, for each simulation area, a plurality of coating parameters of the coating corresponding to the simulation area; the plurality of coating parameters including: a plurality of coating porosities, a plurality of active material volume fractions, a conductive agent and a binder volume fraction, and / or tortuosity; The source terms in the solid phase potential equation and the liquid phase potential equation are: the reaction current density J of the active material particles in the simulation area corresponding to the i-th layer of coating i ; The source term of the liquid phase lithium ion concentration diffusion equation is: the reaction current density J of the active material particles in the simulation area corresponding to the i-th layer of coating i corresponding lithium ion flux; Set the boundary flux to the reaction current density J of the active material particles in the simulation area corresponding to the i-th layer of coating i , based on the boundary flux, the solid-phase lithium ion diffusion equation is solved in the active material particle sub-region within the simulation region corresponding to the i-th coating layer.

2. A multi-layer coated reduced-order model electrochemical simulation device, characterized in that: The device comprises: A region division module is used to divide the positive and negative electrodes of the simulation model of the multi-layer coated battery cell into multiple simulation regions, each simulation region corresponding to the multi-layer coating of the battery cell; An electrochemical simulation module is used to establish a reduced-order model based on regional simulation parameters corresponding to each simulation region to perform electrochemical simulation on the battery cell; the module includes: determining the reaction current density in each simulation region, the sum of the reaction current densities being equal to the external circuit current of the battery cell; solving the diffusion equation within the active material particles within each simulation region to obtain the lithium ion concentration within the active material particles; and modifying the source terms in the solid phase potential equation, the liquid phase potential equation, and the electrolyte lithium ion concentration equation from the reaction current density of the active material within one simulation region to the reaction current density of the active material within multiple simulation regions; The external circuit current is expressed by the following formula: Where i represents the i-th layer of coating, dx is the length element in the thickness direction of the battery cell, It represents the integral within the i-layer coating area, J i is the reaction current density of each active substance in the i-th layer of coating, F is the Faraday constant, k i is the reaction rate constant of each active substance in the i-th coating layer, c l is the lithium ion concentration of the electrolyte, c l,ref is the lithium ion concentration of the reference electrolyte, α a +α c =1 is the transfer coefficient, c s,max,i is the maximum lithium ion concentration of the active material in the i-th coating layer, c s,surf,i is the lithium ion concentration on the surface of the active material particles in the i-th coating layer, R is the ideal gas constant, T is the temperature, η i =φ s -φ l -E eq,i is the overvoltage, where φ s is the solid phase potential, φ l is the liquid phase potential, E eq,i is the equilibrium potential of the active material in each layer; r i is the radius of the active material particle in the i-th coating layer, ε s,i is the volume fraction of active material particles in the i-th coating layer, β i is the specific surface area of ​​the active material particles in the i-th coating layer; A first setting module is configured to set a plurality of simulated active substances in each simulation area; the plurality of simulated active substances includes: a plurality of active substance particles and / or a plurality of active substance particle sizes; and / or, The second setting module is used to set multiple coating parameters of the coating corresponding to each simulation area; the multiple coating parameters include: multiple coating porosities, multiple active material volume fractions, conductive agent and binder volume fractions, and / or tortuosity.

3. The device according to claim 2, characterized in that The electrochemical simulation module is used to: Determine the reaction current density in each simulation area, the sum of the reaction current densities being equal to the external circuit current of the battery cell; Solving the diffusion equation within the active material particles in each simulation area to obtain the lithium ion concentration within the active material particles; The source terms in the solid phase potential equation, liquid phase potential equation and electrolyte lithium ion concentration equation are modified from the reaction current density of active materials in one simulation area to the reaction current density of active materials in multiple simulation areas.

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