MATLAB-based bicontinuous porous structure modeling method, equipment and medium
Through the dual continuous porous structure modeling method based on MATLAB, the isosurface model is generated using the Gaussian random field method and finite element analysis is performed, which solves the problem of difficult to simulate the performance of porous silicon negative electrode materials in the prior art, and achieves efficient and accurate material performance prediction and optimization.
Patent Information
- Application Number
- CN202510036489.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-09
- Publication Date
- 2025-05-06
AI Technical Summary
The prior art is difficult to accurately simulate the relationship between micron-scale porous silicon anode materials and electrochemical and mechanical parameters during charging and discharging, resulting in the inability to effectively optimize material performance.
Using the dual continuous porous structure modeling method based on MATLAB, isosurface models are generated by the Gaussian random field method, and the grid is patched and divided by 3-matic Research software, and finally the finite element model that can be readable by ABAQUS is derived to achieve accurate simulation of porous silicon structure.
This method can accurately simulate the connectivity of holes and its complex microstructure, improve the accuracy and efficiency of material performance prediction, significantly reduce costs and manpower and material costs, and support interdisciplinary research and application.
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Figure CN119940015A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of lithium battery performance simulation, and in particular to a MATLAB-based double-continuous porous structure modeling method, equipment and medium. Background Art
[0002] Lithium-ion batteries are key energy storage devices, and improving the performance of lithium-ion batteries in extreme environments and increasing battery capacity have become urgent issues to be addressed. At present, the commonly used negative electrode material for lithium-ion batteries is commercial graphite negative electrode, but its theoretical specific capacity is limited, only 350 mAh / g. In contrast, Si negative electrode is regarded as the most promising negative electrode material due to its high theoretical specific capacity (theoretical value is 4200 mAh / g), abundant crustal reserves, mature industrial technology and suitable lithium deintercalation platform voltage. The application of silicon negative electrode in lithium-ion batteries has attracted much attention due to its high energy density, but unlike the embedded processing mechanism of graphite negative electrode, silicon will combine with lithium to form different alloy phases during the charging and discharging process, so there is also a significant volume expansion problem. Silicon will undergo huge volume changes during lithiation (such as Figure 1 ), which may lead to the destruction of the electrode structure and thus reduce the performance and cycle life of the battery.
[0003] A team proposed a structurally stable ant nest-like porous micro-silicon material (such as Figure 2 ), the structure can be maintained intact and the volume hardly changes during the charge and discharge process. The three-dimensional porous micron silicon particles constructed by the nano-skeleton show excellent structural stability and electrochemical cycling performance. However, the multi-physical field evolution law of the ant nest-like three-dimensional porous micron silicon negative electrode material and its electrochemical stability mechanism during the cycle are still unclear. Traditional experimental methods often greatly increase the cost of manpower and material resources. Therefore, it is necessary to reveal the relationship between the porous silicon structure parameters and the electrochemical (mechanical) properties through simulation analysis.
[0004] In the past, people's research on nanoporous materials often simplified the model and only considered simple, regular and orderly arranged nanopores. In order to more accurately describe the nanoporous structure, a bicontinuous porous structure that is more in line with the actual situation was selected for modeling. The methods for constructing a bicontinuous porous model mainly include: phase field method, Kinetic Monte Carlo method and Gaussian random field method using Cahn-Hillard equation for phase separation. Although the first two methods can produce bicontinuous porous structures similar to those prepared experimentally, they both require considerable computing resources, and the above modeling methods are more suitable for research at the microscopic scale. This has caused unnecessary restrictions on the structural research of nanoporous materials at a more macroscopic scale through finite element simulation, especially when it is necessary to construct a large number of models with different configurations, porosities and pore sizes, the disadvantages are particularly obvious.
[0005] The Gaussian random field method is more efficient in generating random bicontinuous porous structures, but the model it produces does not have periodic boundaries. Soyarslan et al. modified it to generate a bicontinuous porous model with periodic boundaries, but required the model to be a cube. On this basis, Liu et al. proposed a method to generate a periodic bicontinuous nanoporous structure in a parallelepiped, simulating the porous structure at the atomic level by calling the LAMMPS software and generating a nanoscale porous structure by deleting some atoms. However, the particles of porous silicon negative electrode materials in experiments are often micrometer-sized. Therefore, the structure proposed by Liu et al. cannot directly match the porous silicon materials used in actual applications. Summary of the invention
[0006] In view of the problem in the prior art that micron-scale porous silicon negative electrode materials cannot accurately reflect the random pores obtained by template pore formation, and thus cannot simulate the relationship between the random pores and electrochemical and mechanical parameter performances, the present invention provides a MATLAB-based dual-continuous porous structure modeling method, equipment and medium, which are used to reveal the relationship between porous silicon structural parameters and electrochemical (mechanical) properties, and accelerate the iterative upgrade of new porous silicon negative electrodes.
[0007] The present invention is achieved through the following technical solutions: A bicontinuous porous structure modeling method based on MATLAB comprises the following steps: S1, based on the Gaussian random field method, the solid and the hole are distinguished by superimposing the sine wave vector, and the isosurface model is generated based on MATLAB, and the model is exported as an STL file; S2, import the STL file obtained in S1 into 3-matic Research software, repair the damaged surface, and generate a bicontinuous porous structure similar to an ant nest; S3, using 3-matic Research software to divide the bicontinuous porous structure obtained in S2 into tetrahedral meshes, and export the divided tetrahedral meshes into .inp format files that can be read by ABAQUS; S4, import the structural model and properties into the finite element analysis software to obtain an ant nest-like visualized bicontinuous porous structure model.
[0008] Preferably, in S1, when distinguishing, the Gaussian random field is generated by superposition of sinusoidal waves with fixed amplitude and wavelength and random direction and phase.
[0009] Preferably, the sine wave is represented as:
[0010] in, is the position vector, represents the wave number in the truncated series, is the normalization factor, and Respectively represent The direction and phase of the wave, is a set of uniformly distributed Random phase within range, Must meet , Is a constant.
[0011] Preferred, differentiated, set standards Value, when When , it represents the surface of the entity, represents the porosity of the bicontinuous porous structure; when Greater than When , it indicates a hole; when Less than , it is represented as an entity.
[0012] Preferably, The following conditions are met:
[0013] in, , , is the edge vector of the model, , , is an integer.
[0014] Preferably, the specific steps of distinguishing entities from holes by superimposing sinusoidal wave vectors based on the Gaussian random field method, generating an isosurface model based on MATLAB, and exporting the model as an STL file are as follows: S11, initialization parameters: set lattice constants a, b, c, set grid point number ngp and ligament control size H and its variation range Hlo and Hhi; S12, calculate lattice parameters: calculate the lattice transformation matrix M using the given angles gamma, alpha, beta; S13, calculating the target wave vector q: calculating the target wave vector dq, and its minimum and maximum values qlo and qhi according to the parameters; converting the spherical coordinates into Cartesian coordinates, and calculating the target q; S14, screening integer lattice points: calculating integer lattice points i1, i2, i3 according to the grid point information, and filtering out valid wave vectors according to the screening conditions; S15, calculate the scalar field v: use the function to calculate the scalar field value of each point and reshape the result into the shape of the grid; S16, using the sosurface function in MATLAB to generate an isosurface model of the scalar field; S17, use surf2stl to export the generated isosurface model as an STL file.
[0015] Preferably, in S2, the missing surfaces are manually filled by using the merge command, and the edges or vertices are repaired by using the create bridge command and the merge command in sequence to ensure that an ant nest-like bicontinuous porous structure is generated.
[0016] Preferably, it also includes model simulation, applying corresponding boundary conditions to the ant nest-like visualized bicontinuous porous structure model obtained in S4, and characterizing the pore size parameters of the porous structure using zeo++ software by reading the coordinate information of the unit nodes in the finite element.
[0017] An electronic device comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the modeling method when executing the computer program.
[0018] A storage medium stores a computer program, which implements the steps of the modeling method when executed by a processor.
[0019] Compared with the prior art, the present invention has the following beneficial effects: The bicontinuous porous structure modeling method based on MATLAB of the present invention is more practical by constructing a bicontinuous porous structure through the Gaussian random field method, which can accurately simulate the connectivity of the pores and their complex microstructures, and is particularly suitable for the performance prediction of porous silicon negative electrode materials. Secondly, the use of MATLAB for modeling not only improves the modeling efficiency, but also ensures high accuracy, can generate accurate porous material models in a short time and support complex finite element analysis, and significantly improves the efficiency of simulation analysis. In addition, the present invention can reveal the relationship between the geometric parameters of the porous silicon structure and the electrochemical and mechanical properties, and provides theoretical support for the optimization of material properties. The method has a wide range of applicability. In addition to the silicon negative electrode, it can also be applied to other nano / micrometer-scale porous materials, such as catalysts, gas storage materials, etc. Compared with traditional modeling methods, the present invention greatly reduces costs and improves operability, and has strong flexibility, and can be customized according to different needs. At the same time, it supports interdisciplinary research and application, and promotes cooperation and development in the fields of materials science, chemistry, physics, etc. Through the combination with experimental data, the present invention not only promotes the progress of material research and development, but also provides a practical optimization scheme for industrial applications, and has broad application prospects.
[0020] Furthermore, by generating isosurfaces of the scalar field, the manual repair of bad surfaces in the 3-matic Research software can be omitted. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 It is a graph showing the volume expansion change of Si caused by lithium insertion in the prior art; Figure 2 It is the design and principle diagram of the synthesis method of a certain ant nest-shaped micro-scale porous silicon AMPSi in the prior art; Figure 3 It is a flow chart of a bicontinuous porous structure modeling method based on MATLAB of the present invention; Figure 4 This is the basic modeling process of the bicontinuous porous silicon model in the present invention; Figure 5 It is a model flow chart of a bicontinuous porous structure modeling method based on MATLAB of the present invention; Figure 6 These are configurations of bicontinuous porous structures with different pore size parameters in the present invention; Figure 7 is a schematic diagram of the atomic structure of a bicontinuous porous structure in an embodiment of the present invention; Figure 8 This is a test diagram of a quasi-static compression test of a bicontinuous porous structure in an embodiment of the present invention. DETAILED DESCRIPTION
[0022] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.
[0023] The present invention discloses a bicontinuous porous structure modeling method based on MATLAB, referring to Figure 1 , including the following steps: A bicontinuous porous structure modeling method based on MATLAB comprises the following steps: S1, based on the Gaussian random field method, the solid and the hole are distinguished by superimposing the sine wave vector, and the isosurface model is generated based on MATLAB, and the model is exported as an STL file; the specific steps are as follows: S11, initialization parameters: set lattice constants a, b, c, set grid point number ngp and ligament control size H and its variation range Hlo and Hhi; S12, calculate lattice parameters: calculate the lattice transformation matrix M using the given angles gamma, alpha, beta; S13, calculating the target wave vector q: calculating the target wave vector dq, and its minimum and maximum values qlo and qhi according to the parameters; converting the spherical coordinates into Cartesian coordinates, and calculating the target q; S14, screening integer lattice points: calculating integer lattice points i1, i2, i3 according to the grid point information, and filtering out valid wave vectors according to the screening conditions; S15, calculate the scalar field v: use the function to calculate the scalar field value of each point and reshape the result into the shape of the grid; S16, using the sosurface function in MATLAB to generate an isosurface model of the scalar field; S17, use surf2stl to export the generated isosurface model as an STL file.
[0024] The modeling idea is: read the model parameters through MATLAB ( , , and , , ) and for the coordinates ( ); Then, program to calculate the corresponding value of each unit , and finally delete unit.
[0025] Among them, when distinguishing, the Gaussian random field is generated by the superposition of sine waves with fixed amplitude and wavelength but random direction and phase.
[0026] The representation of a sine wave is:
[0027] in, is the position vector, represents the wave number in the truncated series, is the normalization factor, and Respectively represent The direction and phase of the wave, is a set of uniformly distributed Random phase within range, Must meet , is a constant used to control the size of the ligament.
[0028] When distinguishing, give a standard The value distinguishes solids from holes. When , it represents the surface of the entity, represents the porosity of the bicontinuous porous structure; when Greater than When , it indicates a hole; when Less than , it is represented as an entity. The value of can be used to control the porosity of the bicontinuous porous structure, for example It means the porosity is approximately equal to 0.5.
[0029] In order to construct a bicontinuous porous structure with periodic boundary conditions in space, The following conditions are met:
[0030] in, , , is the edge vector of the model, , , is an integer.
[0031] In order to meet the above conditions, we have:
[0032] The above formula means:
[0033] , , is an integer. Therefore, Must meet:
[0034] in,
[0035] a, b, c are the lengths of vectors a, b, c respectively, , , They are , , Angle.
[0036] In order to ensure that the generated porous structure is more random, the number of waves should be as large as possible. The wave vectors of these waves are evenly distributed in a grid of size The solid angle of is the entire sphere. The cylindrical coordinates of the grid points are ,in is the golden angle (~137.508º), is the total number of grid points, here we take . Then convert the above cylindrical coordinates to Cartesian coordinates and multiply by the desired Value, take , thus we can get the accurate wave vector In order to show periodicity in a parallelepiped, we need to make ,in All are integers.
[0037] In order to make the final structure a periodic structure, it is required to Before that, we need to determine the integer , and .
[0038] First, by Get the nearest integer , and then calculate according to the following formula :
[0039] Secondly, by Get the nearest integer , and then calculate according to the following formula :
[0040] Finally, by Get the nearest integer , and then calculate according to the following formula :
[0041] In order to ensure that the porous structure has a clear ligament size distribution, only exist Between .
[0042] S2, import the STL file obtained in S1 into 3-matic Research software, and manually fill the missing surfaces through the merge command to generate an ant nest-like bicontinuous porous structure; among them, for the edges or vertices, use the create bridge command and the merge command in turn to repair them to ensure the generation of an ant nest-like bicontinuous porous structure, and connect and assign some amplitudes on the outermost surface to the isosurface through code algorithm optimization, which greatly improves the modeling speed.
[0043] S3, using 3-matic Research software to divide the bicontinuous porous structure obtained in S2 into tetrahedral meshes (such as C3D4), and export the divided tetrahedral meshes into .inp format files that can be read by ABAQUS; S4, import the structural model and properties into the finite element analysis software to obtain a visual bicontinuous porous structure model similar to an ant nest. Among them, the properties include mechanical performance parameters such as elastic modulus, yield strength, and Poisson's ratio. For example, since the Si negative electrode will exist in an amorphous state after the first cycle of charge and discharge, the mechanical performance parameters of a-Si can be selected to assign to the constructed bicontinuous porous model. The mechanical performance parameters of amorphous silicon are: Young's modulus 90 GPa, Poisson's ratio 0.28, and yield strength 6.5 Gpa.
[0044] S5, model simulation, applies corresponding boundary conditions to the ant nest-like visualized bicontinuous porous structure model obtained in S4, and uses zeo++ software to characterize the pore size parameters of the porous structure by reading the coordinate information of the unit nodes in the finite element.
[0045] Among them, the boundary condition is to apply displacement loading. For example, during the tensile test, two boundary conditions BC-1 and BC-2 need to be applied to the model. Among them, BC-1 is the fixed end and BC-2 can change its displacement, thereby realizing the tensile test simulation process.
[0046] Taking a bicontinuous porous structure as an example, in the ABAQUS finite element simulation software, the configuration is exported as a .inp format file, which contains the coordinates of the unit nodes. Following the atomic data file format, it is assigned the properties of a certain atom, and the following can be obtained: Figure 7 The atomic model mentioned.
[0047] like Figure 8The compaction density of porous silicon negative electrode has a significant impact on the battery capacity, and the mechanical properties of porous materials are usually affected by factors such as porosity and pore size distribution. Quasi-static compression simulation can effectively analyze the influence of different pore structures on the mechanical properties of materials, revealing the laws of porosity, pore size and pore structure on mechanical properties such as compressive strength and elastic modulus of materials, thereby providing a theoretical basis for the design of porous silicon negative electrodes. In addition, quasi-static compression simulation can also deeply explore the influence of different microstructures on the mechanical behavior of silicon negative electrodes, and provide guidance for optimizing the mechanical properties of porous silicon materials. For example, by adjusting microstructural parameters such as porosity and pore size distribution, the optimization of mechanical properties can be achieved, thereby improving the efficiency and cycle life of the battery.
[0048] The present invention provides a MATLAB-based bicontinuous porous structure modeling method, which constructs a more realistic ant nest-like bicontinuous porous structure through the Gaussian random field method, and conducts subsequent analysis on this structure, which is expected to promote the development of new porous Si negative electrodes, and can reveal the relationship between the geometric parameters of the porous silicon structure and its electrochemical and mechanical properties. It can not only be used for silicon negative electrode materials, but also can be widely used in the modeling and analysis of other nano / micrometer-scale porous structures.
[0049] The present invention discloses an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the modeling method when executing the computer program.
[0050] The invention discloses a storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the modeling method are realized.
[0051] The above description is only a preferred embodiment of the present invention and is not intended to impose any limitation on the technical solution of the present invention. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can also be subjected to several simple modifications and substitutions, and these modifications and substitutions are also within the scope of protection covered by the claims.
Claims
1. A bicontinuous porous structure modeling method based on MATLAB, characterized in that: The following steps are involved: S1, based on the Gaussian random field method, the solid and the hole are distinguished by superimposing the sine wave vector, and the isosurface model is generated based on MATLAB, and the model is exported as an STL file; S2, import the STL file obtained in S1 into 3-matic Research software, repair the damaged surface, and generate a bicontinuous porous structure similar to an ant nest; S3, using 3-matic Research software to divide the bicontinuous porous structure obtained in S2 into tetrahedral meshes, and export the divided tetrahedral meshes into .inp format files that can be read by ABAQUS; S4, import the structural model and properties into the finite element analysis software to obtain an ant nest-like visualized bicontinuous porous structure model.
2. The MATLAB-based bicontinuous porous structure modeling method according to claim 1, characterized in that: In S1, when distinguishing, the Gaussian random field is generated by the superposition of sine waves with fixed amplitude and wavelength but random direction and phase.
3. The MATLAB-based bicontinuous porous structure modeling method according to claim 2, characterized in that: The representation of a sine wave is: in, is the position vector, represents the wave number in the truncated series, is the normalization factor, and Respectively represent The direction and phase of the wave, is a set of uniformly distributed Random phase within range, Must meet , Is a constant.
4. The MATLAB-based bicontinuous porous structure modeling method according to claim 2, characterized in that: When differentiating, set standards Value, when When , it represents the surface of the entity, represents the porosity of the bicontinuous porous structure; when Greater than When , it indicates a hole; when Less than , it is represented as an entity.
5. The MATLAB-based bicontinuous porous structure modeling method according to claim 4, characterized in that: The following conditions are met: in, , , is the edge vector of the model, , , is an integer.
6. The bicontinuous porous structure modeling method based on MATLAB according to claim 1, characterized in that: The specific steps of distinguishing entities from holes by superimposing sine wave vectors based on the Gaussian random field method, generating an isosurface model based on MATLAB, and exporting the model as an STL file are as follows: S11, initialization parameters: set lattice constants a, b, c, set grid point number ngp and ligament control size H and its variation range Hlo and Hhi; S12, calculate lattice parameters: calculate the lattice transformation matrix M using the given angles gamma, alpha, beta; S13, calculating the target wave vector q: calculating the target wave vector dq, and its minimum and maximum values qlo and qhi according to the parameters; Convert spherical coordinates to Cartesian coordinates and calculate the q of the target; S14, screening integer lattice points: calculating integer lattice points i1, i2, i3 according to the grid point information, and filtering out valid wave vectors according to the screening conditions; S15, calculate the scalar field v: use the function to calculate the scalar field value of each point and reshape the result into the shape of the grid; S16, using the sosurface function in MATLAB to generate an isosurface model of the scalar field; S17, use surf2stl to export the generated isosurface model as an STL file.
7. The bicontinuous porous structure modeling method based on MATLAB according to claim 1, characterized in that: In S2, the merge command is used to manually fill in the missing surfaces. For edges or vertices, the create bridge command and the merge command are used in sequence to repair them to ensure the generation of an ant nest-like bicontinuous porous structure.
8. The bicontinuous porous structure modeling method based on MATLAB according to claim 1, characterized in that: It also includes model simulation, applying corresponding boundary conditions to the ant nest-like visualized bicontinuous porous structure model obtained by S4, and characterizing the pore size parameters of the porous structure using zeo++ software by reading the coordinate information of the unit nodes in the finite element.
9. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the modeling method according to any one of claims 1 to 8 are implemented.
10. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the modeling method according to any one of claims 1 to 8 are implemented.