Micro-scale multi-physics field coupling simulation method for structural energy storage integrated composite material

Abstract

The invention discloses a micro-scale multi-physics coupling simulation method for a structural energy storage integrated composite material, and belongs to the field of structural battery simulation. The method comprises the steps of obtaining feature size parameters of each part of a target structure battery; carrying out geometric modeling on the target structure battery based on the characteristic size parameters, and respectively endowing electrochemical material parameters and mechanical parameters to each part of a geometric model; a lithium ion battery physical field containing a calculation function and a solid mechanical physical field containing a calculation function are constructed, and when the lithium ion concentration of the positive electrode active layer and the negative electrode active layer is updated in real time through the lithium ion battery physical field, the solid mechanical physical field solves intercalation strain of the positive electrode active layer and the negative electrode active layer at the same time based on the lithium ion concentration. And carrying out multi-physics field coupling simulation calculation on the target structure battery. According to the scheme, the influence of intercalation expansion / shrinkage of the positive and negative active layers in the structural battery on the overall mechanical and electrical properties of the structural battery can be truly reflected, so that a more real structural battery model is established.

Description

Technical Field

[0001] This invention relates to the field of structural battery simulation technology, and in particular to a microscale multiphysics coupling simulation method for structural energy storage integrated composite materials. Background Technology

[0002] Structural batteries aim to combine storage and mechanical support functions, which are not achieved by two separate components in the system, but by the same materials. This concept can be realized by incorporating carbon fibers as the active electrode material into lithium-ion batteries (LIBs), potentially creating a synergistic, multifunctional battery that could provide significant mass and volume savings at the system level, leading to more efficient structures.

[0003] Existing structural batteries typically consist of three layers: a negative electrode primarily composed of carbon fiber, a positive electrode using short glass fiber cloth as an electrically insulating membrane, and a carbon fiber fabric as a current collector-reinforcing active layer, all immersed in an ion-conducting electrolyte. The function of a lithium-ion battery is to transfer lithium ions (Li-ions) between the negative and positive electrodes via the electrolyte, while the corresponding electrons pass through the external circuit as an electric current. Lithium ions typically intercalate into the negative and positive electrodes through an intercalation process, interconnecting within the microstructure of the electrode materials. During charging, lithium ions are deposited from the positive electrode, cross the electrolyte, and enter the negative electrode.

[0004] However, the performance of existing structural batteries is generally poor, and current structural battery modeling methods do not provide a realistic model of the positive electrode composed of active layers and carbon fibers. Furthermore, the physical fields of lithium-ion batteries and solid mechanical fields are simulated independently, which cannot truly reflect the impact of the intercalation expansion / contraction of the positive and negative electrode active layers on the overall electromechanical performance of the structural battery.

[0005] Therefore, there is an urgent need to provide a multi-physics coupling simulation method at the microscale of structural energy storage integrated composite materials. Summary of the Invention

[0006] To address the issue that existing structural batteries generally have mediocre performance, and that current modeling methods simulate physical fields and solid mechanical fields independently, failing to accurately reflect the impact of intercalation expansion / contraction of the positive and negative electrode active layers on the overall electromechanical performance of the structural battery, this invention provides a microscale multiphysics coupling simulation method for integrated structural energy storage composite materials.

[0007] On the one hand, a multiphysics coupling simulation method for structural energy storage integrated composite materials at the microscale is provided, the method comprising:

[0008] Obtain the characteristic dimension parameters of each part of the target structure battery; wherein, the target structure battery includes a positive electrode composed of a carbon fiber fabric current collector and a positive electrode active layer, a separator, a negative electrode composed of a carbon fiber fabric current collector and a negative electrode active layer, and an electrolyte;

[0009] Based on the aforementioned characteristic size parameters, a geometric model of the target structure battery is performed, and electrochemical material parameters and mechanical parameters are assigned to each part of the geometric model respectively.

[0010] Construct a lithium-ion battery physical field and a solid-state mechanical physical field containing computational functions, and set initial conditions and boundary conditions for the lithium-ion battery physical field and the solid-state mechanical physical field respectively;

[0011] After meshing the geometric model, a solver is configured to update the lithium-ion concentration of the positive and negative active layers in real time using the lithium-ion battery physical field. At the same time, the solid mechanics physical field solves for the intercalation strain of the positive and negative active layers based on the lithium-ion concentration to perform multi-physics coupled finite element simulation calculation of the target structure battery.

[0012] On the other hand, a multiphysics coupling simulation device for structural energy storage integrated composite materials at the microscale is provided, used to implement the steps described in any method embodiment of the specification, the device comprising:

[0013] The acquisition unit is used to acquire the characteristic size parameters of each part of the target structure battery; wherein, the target structure battery includes a positive electrode composed of a carbon fiber fabric current collector and a positive electrode active layer, a separator, a negative electrode composed of a carbon fiber fabric current collector and a negative electrode active layer, and an electrolyte;

[0014] The modeling unit is used to perform geometric modeling of the target structure battery based on the feature size parameters, and to assign electrochemical material parameters and mechanical parameters to each part of the geometric model respectively;

[0015] The setting unit is used to construct the lithium-ion battery physical field and the solid mechanical physical field containing the calculation function, and to set the initial conditions and boundary conditions for the lithium-ion battery physical field and the solid mechanical physical field respectively.

[0016] The simulation unit is configured to perform multi-physics coupled finite element simulation calculations of the target structure battery by configuring a solver after meshing the geometric model, so that when the lithium-ion concentration of the positive electrode active layer and the negative electrode active layer is updated in real time using the lithium-ion battery physical field, the solid mechanical physical field simultaneously solves the intercalation strain of the positive electrode active layer and the negative electrode active layer based on the lithium-ion concentration.

[0017] On the other hand, a computer device is provided, the computer device including a memory and a processor, the memory for storing a computer program, and the processor for executing the computer program stored in the memory to implement the steps of the method described above.

[0018] On the other hand, a computer-readable storage medium is provided, wherein a computer program is stored therein, and when the computer program is executed by a processor, it implements the steps of the method described above.

[0019] On the other hand, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps of the method described above.

[0020] The technical solution provided by this invention can bring at least the following beneficial effects:

[0021] Using a laminated energy storage composite material consisting of a carbon fiber fabric current collector and a negative electrode active layer as the negative electrode can result in higher battery capacity, higher cycle retention, and optimized electrical performance. Furthermore, by geometrically modeling the target battery structure and constructing a multiphysics model, while using the lithium-ion battery physics field to update the lithium-ion concentrations of the positive and negative electrode active layers in real time, the solid mechanics physics field simultaneously solves for the intercalation strain of the positive and negative electrode active layers based on the lithium-ion concentration. This multiphysics coupled simulation method can realistically reflect the impact of the intercalation expansion / contraction of the positive and negative electrode active layers on the overall electromechanical performance of the battery structure, thus establishing a more realistic battery structure model. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a flowchart of a multi-physics coupling simulation method for structural energy storage integrated composite materials at the microscale, provided by an embodiment of the present invention.

[0024] Figure 2 This is a schematic diagram of a target structure battery provided in an embodiment of the present invention;

[0025] Figure 3 This is a structural diagram of a composite material microscale multiphysics coupling simulation device for integrated energy storage provided in an embodiment of the present invention;

[0026] Figure 4This is a hardware architecture diagram of a computer device provided in an embodiment of the present invention;

[0027] Figure label:

[0028] 1-Positive electrode active layer; 2-Negative electrode active layer; 3-Carbon fiber fabric current collector; 4-Separator; 5-Electrolyte. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0030] The following describes the specific implementation of the above concept.

[0031] Please refer to Figure 1 The present invention provides a method for multi-physics coupling simulation at the microscale of structural energy storage integrated composite materials, the method comprising:

[0032] Step 100: Obtain the characteristic size parameters of each part of the target structure battery; wherein, the target structure battery includes a positive electrode composed of a carbon fiber fabric current collector and a positive electrode active layer, a separator, a negative electrode composed of a carbon fiber fabric current collector and a negative electrode active layer, and an electrolyte;

[0033] Step 102: Based on the characteristic size parameters, perform geometric modeling of the target structure battery, and assign electrochemical material parameters and mechanical parameters to each part of the geometric model respectively;

[0034] Step 104: Construct the physical field of the lithium-ion battery and the physical field of the solid mechanics containing the calculation function, and set the initial conditions and boundary conditions for the physical field of the lithium-ion battery and the physical field of the solid mechanics respectively;

[0035] Step 106: After meshing the geometric model, configure the solver so that when the lithium-ion concentration of the positive and negative active layers is updated in real time using the lithium-ion battery physical field, the solid mechanics physical field simultaneously solves the intercalation strain of the positive and negative active layers based on the lithium-ion concentration, so as to perform multi-physics coupled finite element simulation calculation of the target structure battery.

[0036] In this embodiment of the invention, a laminated energy storage composite material consisting of a carbon fiber fabric current collector and a negative electrode active layer is used as the negative electrode, which can result in higher battery capacity, higher cycle retention, and optimized electrical performance. Furthermore, by geometrically modeling the target battery structure and constructing a multiphysics field, while using the lithium-ion battery physical field to update the lithium-ion concentrations of the positive and negative electrode active layers in real time, the solid mechanics physical field simultaneously solves for the intercalation strain of the positive and negative electrode active layers based on the lithium-ion concentration. This multiphysics coupled simulation calculation method can realistically reflect the impact of the intercalation expansion / contraction of the positive and negative electrode active layers on the overall electromechanical performance of the battery structure, thereby establishing a more realistic battery structure model.

[0037] The following description Figure 1 The execution method for each step is shown.

[0038] For step 100:

[0039] In some embodiments, the diaphragm material is woven fiberglass cloth.

[0040] refer to Figure 2 The schematic diagram of the target structure battery shows that the separator between the positive and negative electrodes can be made of woven glass fiber cloth. Since the mechanical properties depend on the orientation of the fibers, the existing electrical insulating separators use short glass fiber cloth or carbon fiber bundles, and their strength and stiffness are not as good as the woven glass fiber cloth of this embodiment.

[0041] In addition, using solid-state battery electrolyte (SBE) instead of liquid electrolyte can improve the mechanical properties of structural batteries.

[0042] In some implementations, the characteristic dimension parameters of each part of the target structure battery are obtained in the following manner:

[0043] The target structure battery was fabricated, and its cross-section was photographed using a super depth-of-field microscope.

[0044] The cross-sectional image was analyzed using image analysis software. Based on the scaling ratio between the cross-sectional image and the target battery structure, the characteristic dimensional parameters of each part of the target battery structure were measured and determined using the measurement tools in the image analysis software. Among them, the characteristic dimensional parameters include at least: the shape and size of the positive and negative active layers, the cross-sectional shape, yarn height and yarn direction of the carbon fiber fabric current collector in the positive and negative electrodes, and the cross-sectional shape, yarn height and yarn direction of the woven glass fiber cloth separator.

[0045] In this embodiment, the fabrication is as follows Figure 2The target structural battery shown was imaged using a super depth-of-field microscope to capture the desired cross-sectional image. Ensure the image is sharp and the sample size is within the microscope's measurement range. Image analysis was performed using ImageJ, MATLAB, or dedicated microscope image analysis software. Before analysis, the image needs to be calibrated, which involves setting the image scaling ratio, i.e., the actual physical size represented per pixel. This can be calibrated using a target structural battery sample of known size, or calculated based on the microscope's magnification and image resolution. In the image analysis software, an appropriate measurement tool was selected, such as a line tool, circle tool, or custom shape tool, depending on the type of size to be measured. The measurement tool was used to measure along the edge of the sample to be measured on the image. The software automatically calculated the actual physical size based on the calibrated scaling ratio and recorded the measurement results.

[0046] Regarding step 102:

[0047] In this embodiment of the invention, the characteristic size parameters of each part of the target structure battery extracted in step 100 are used to model the cross-sectional shape, yarn height, and yarn direction of the carbon fiber fabric current collector, the shape and size (length, width, and thickness) of the positive and negative electrode active layers, and the cross-sectional shape, yarn height, and yarn direction of the glass fiber fabric separator in the TexGen modeling software. The established geometric model is then imported into the COMSOL analysis software, and electrochemical material parameters and mechanical parameters are assigned to each part of the geometric model.

[0048] In some implementations, electrochemical material parameters and mechanical parameters are assigned to various parts of the geometric model, including:

[0049] Electrochemical material parameters for maximizing lithium-ion concentration and conductivity, as well as mechanical parameters for Young's modulus and Poisson's ratio, are assigned to the positive and negative active layers, respectively. The positive active layer is composed of lithium nickel cobalt manganese oxide, conductive carbon black, and a binder, while the negative active layer is composed of graphite, conductive carbon black, and a binder.

[0050] It imparts conductivity to the electrolyte and Young's modulus and Poisson's ratio to the carbon fiber fabric current collector;

[0051] To impart Young's modulus and Poisson's ratio to the diaphragm.

[0052] In this embodiment, in COMSOL, materials are assigned to each part of the geometric model, and then the electrochemical material parameters (conductivity, maximum lithium-ion concentration, particle radius, etc.) and mechanical parameters (Young's modulus, Poisson's ratio, etc.) of the positive and negative electrode active layers, carbon fiber fabric current collector, glass fiber diaphragm, resin matrix, and electrolyte are determined step by step.

[0053] Regarding step 104:

[0054] In some implementations, step 104 may include:

[0055] Add the corresponding theoretical calculation functions for the lithium-ion battery physical field and solid mechanics physical field in the COMSOL analysis software; where the lithium-ion battery physical field is based on the porous electrode theory and the solid mechanics physical field is based on the linear elastic material theory.

[0056] In the physical field of a lithium-ion battery, the exchange current density, the volume fraction of lithium ions in the solid and liquid phases, and the radii of the positive and negative electrode active particles are set.

[0057] Set the potential boundary condition for the positive current density and ground the negative terminal.

[0058] In this embodiment, initial and boundary conditions are set for the lithium-ion battery physical field and the solid mechanics physical field involved in the modeling process in COMSOL. In the solid mechanics physical field of COMSOL, the intercalation strain of the positive and negative electrodes is set.

[0059] Regarding step 106:

[0060] In this step, the geometric model is first meshed. The mesh is refined near the membrane interface and the carbon fiber current collector interface of the positive and negative electrode active layers, while the mesh can be appropriately coarsened in the resin region on the outer side of the positive and negative electrodes. This is because the chemical and physical reactions in the physical field are mainly concentrated near the membrane interface and the carbon fiber current collector interface; refining the mesh can improve accuracy and computational precision. The resin region on the outer side of the positive and negative electrodes varies less, so the mesh can be appropriately coarsened to improve computational efficiency.

[0061] After the model mesh is generated, parametric scanning control of the charge and discharge rate is added, and the solver is configured. After the solver is configured, finite element simulation calculations are performed on the meshed structural battery model to obtain the COMSOL simulation results and analyze the simulation results.

[0062] In some implementations, the multiphysics coupled finite element simulation calculation method for the target structure battery is as follows:

[0063] Based on the electrochemical material parameters of the positive electrode active layer and the electrolyte, the electrochemical reaction kinetic equations, charge conservation equations and mass conservation equations in the physical field of lithium-ion batteries are used to simulate and calculate the electrochemical process of the positive electrode active layer during charging and discharging, including at least the real-time lithium-ion concentration of the positive electrode active layer.

[0064] Based on the electrochemical material parameters of the negative electrode active layer and the electrolyte, the electrochemical reaction kinetic equations, charge conservation equations and mass conservation equations in the physical field of lithium-ion batteries are used to simulate and calculate the electrochemical process of the negative electrode active layer during charging and discharging, including at least the real-time lithium-ion concentration of the negative electrode active layer.

[0065] Based on the real-time lithium-ion concentration of the positive electrode active layer, the intercalation strain of the positive electrode active layer is simulated using the intercalation strain equation in the physical field of solid mechanics. At the same time, the elastic strain of the positive electrode active layer is calculated based on the mechanical parameters of the positive electrode active layer and Hooke's law.

[0066] Based on the real-time lithium-ion concentration of the negative electrode active layer, the intercalation strain of the negative electrode active layer is simulated using the intercalation strain equation in the physical field of solid mechanics. At the same time, the elastic strain of the negative electrode active layer is calculated based on the mechanical parameters of the negative electrode active layer and Hooke's law.

[0067] Based on the mechanical parameters of carbon fiber fabric current collectors and Hooke's law, the elastic strain of carbon fiber fabric current collectors is simulated and calculated.

[0068] Based on the mechanical parameters of the diaphragm and Hooke's law, the elastic strain of the diaphragm is simulated and calculated.

[0069] Determine the potential distribution and stress distribution of the target structure battery under multiple physics fields.

[0070] In this embodiment, the electrochemical processes of the positive and negative active layers are simulated separately to obtain the real-time lithium-ion concentrations of the positive and negative active layers. Simultaneously, using the intercalation strain equation, the intercalation strain of the positive and negative active layers is calculated based on their real-time lithium-ion concentrations. After calculating the elastic strain of the positive and negative active layers, the total strain of the positive and negative active layers can be obtained. Furthermore, the potential and stress distributions of the positive and negative active layers are obtained, thereby realistically reflecting the impact of the intercalation expansion / contraction of the positive and negative active layers on the overall electromechanical performance of the structural battery, and establishing a more realistic structural battery model.

[0071] It is understandable that carbon fiber fabric current collectors and diaphragms only need to calculate the elastic strain of the solid mechanical part, without needing to calculate the intercalation strain and electrochemical process.

[0072] Next, the three sets of equations in the electrochemical section will be explained.

[0073] (1) Electrochemical reaction kinetic equations

[0074] The local charge transfer current density is determined by the Butler-Volmer equation:

[0075]

[0076] In the formula, j n Let α be the local charge transfer current density, j0 be the exchange current density, and α be the local charge transfer current density. a and α c This is the charge transfer coefficient of the electrodes, where subscripts a and c represent the negative and positive electrodes, respectively. η is the local surface overpotential, F is the Faraday constant, R is the ideal gas constant, and T is the temperature; k a and k c c is the reaction rate constant. s,max c is the maximum lithium-ion concentration that can be intercalated in the active layer. s c represents the real-time lithium-ion concentration in the active layer. l c is the lithium ion concentration in the electrolyte. l,ref This represents the reference lithium-ion concentration in the electrolyte; the subscripts 's' and 'l' represent the solid and liquid phases, respectively. eq It is the open-circuit potential of the electrode. It is solid-state potential. It is the liquid phase potential.

[0077] (2) Charge conservation equations

[0078] The governing equations for charge conservation at the positive and negative electrodes are:

[0079]

[0080] In the formula, i s Let i be the solid-state current density. l j is the liquid phase ion current density. n Let S be the local charge transfer current density, and S be the specific surface area, defined as S = 3μ s / R s , where μ s It is the solid volume fraction, R s It is the radius of the positive or negative electrode particle.

[0081] The transport equation of lithium ions in the solid phase:

[0082]

[0083] in, It is the effective conductivity of the solid phase. It is the solid-state potential, and γ is the Bruggeman exponent. It is the ionic conductivity of the solid phase, μ. s This represents the volume fraction of the solid phase.

[0084] The transport equation of lithium ions in the liquid phase:

[0085]

[0086] in, It is the effective ionic conductivity of the liquid phase. It is the liquid phase potential. It is the ionic conductivity of the liquid phase, μ l f is the liquid volume fraction. ± t is the mean molar activity coefficient. + c is the transport number of lithium ions in the liquid phase. l Let F be the lithium ion concentration in the electrolyte, F be the Faraday constant, R be the ideal gas constant, and T be the temperature.

[0087] (3) Mass conservation equations

[0088] The mass conservation equation for lithium ions in the solid active layer is:

[0089]

[0090] Where t is time, D s Let c be the solid-phase diffusion coefficient. s denoted as the real-time lithium-ion concentration in the active layer, and r as the particle radius distance variable, representing the distance of lithium ions from the particle center when the active particles are de-intercalated / intercalated.

[0091] The mass conservation equation for lithium ions in a liquid electrolyte is:

[0092]

[0093] in, D is the effective liquid phase diffusion coefficient. l Let j be the liquid phase diffusion coefficient. n Let F be the local charge transfer current density, and F be the Faraday constant, μ l c is the liquid volume fraction. l denoted as the lithium ion concentration in the electrolyte, S as the specific surface area, and γ as the Bruggeman exponent.

[0094] Next, the solid mechanics section will be explained.

[0095] Total strain of materials in each component of the battery cell Intercalation strain and elastic strain composition:

[0096]

[0097] Among them, intercalation strain It exists only in the positive electrode active layer and the negative electrode active layer.

[0098] elastic strain Calculate using Hooke's Law:

[0099]

[0100] In the formula, E is the Young's modulus of the material, v is the Poisson's ratio of the material, and σ ij For the shear stress component, σ kk is the principal stress of the Cauchy stress tensor.

[0101] Intercalation strain of the active layer:

[0102] Wherein, fun(SOC) is the volume change rate of the active layer, which is a function of the percentage of the battery's current remaining charge relative to its total capacity. SOC is calculated from the real-time lithium-ion concentration in the active layer and is used to reflect the coupling calculation of the electric and force fields.

[0103] For the total strain expansion of the 3D model, we have:

[0104]

[0105] Where, σ xx σ yy σ zz It is the normal stress component, σ xy σ yz σ xz G is the shear stress component, G is the shear modulus, and E is the Young's modulus of the material.

[0106] The relationship between E and G is:

[0107]

[0108] In the formula, v is the Poisson's ratio of the material.

[0109] Please refer to Figure 3 This invention provides a multiphysics coupling simulation device for structural energy storage integrated composite materials at the microscale, used to implement the steps of any method embodiment in the specification. The device includes:

[0110] The acquisition unit 301 is used to acquire the characteristic size parameters of each part of the target structure battery; wherein, the target structure battery includes a positive electrode composed of a carbon fiber fabric current collector and a positive electrode active layer, a separator, a negative electrode composed of a carbon fiber fabric current collector and a negative electrode active layer, and an electrolyte;

[0111] Modeling unit 302 is used to perform geometric modeling of the target structure battery based on feature size parameters, and to assign electrochemical material parameters and mechanical parameters to each part of the geometric model respectively;

[0112] Setting unit 303 is used to construct the lithium-ion battery physical field and the solid mechanical physical field containing the calculation function, and to set the initial conditions and boundary conditions for the lithium-ion battery physical field and the solid mechanical physical field respectively.

[0113] Simulation unit 304 is used to configure a solver after meshing the geometric model, so that when the lithium-ion concentration of the positive and negative active layers is updated in real time using the lithium-ion battery physical field, the solid mechanical physical field is used to solve the intercalation strain of the positive and negative active layers based on the lithium-ion concentration, so as to perform multi-physics coupled finite element simulation calculation of the target structure battery.

[0114] In one embodiment of the present invention, the diaphragm material is woven glass fiber cloth.

[0115] In one embodiment of the present invention, the feature size parameters of each part of the target structure battery in the acquisition unit 301 are obtained in the following manner:

[0116] The target structure battery was fabricated, and its cross-section was photographed using a super depth-of-field microscope.

[0117] The cross-sectional image was analyzed using image analysis software. Based on the scaling ratio between the cross-sectional image and the target battery structure, the characteristic dimensional parameters of each part of the target battery structure were measured and determined using the measurement tools in the image analysis software. Among them, the characteristic dimensional parameters include at least: the shape and size of the positive and negative active layers, the cross-sectional shape, yarn height and yarn direction of the carbon fiber fabric current collector in the positive and negative electrodes, and the cross-sectional shape, yarn height and yarn direction of the woven glass fiber cloth separator.

[0118] In one embodiment of the present invention, the modeling unit 302 assigns electrochemical material parameters and mechanical parameters to various parts of the geometric model, including:

[0119] Electrochemical material parameters for maximizing lithium-ion concentration and conductivity, as well as mechanical parameters for Young's modulus and Poisson's ratio, are assigned to the positive and negative active layers, respectively. The positive active layer is composed of lithium nickel cobalt manganese oxide, conductive carbon black, and a binder, while the negative active layer is composed of graphite, conductive carbon black, and a binder.

[0120] It imparts conductivity to the electrolyte and Young's modulus and Poisson's ratio to the carbon fiber fabric current collector;

[0121] The diaphragm is given Young's modulus and Poisson's ratio.

[0122] In one embodiment of the present invention, the setting unit 303 is used to perform:

[0123] Add the corresponding theoretical calculation functions for the lithium-ion battery physical field and solid mechanics physical field in the COMSOL analysis software; where the lithium-ion battery physical field is based on the porous electrode theory and the solid mechanics physical field is based on the linear elastic material theory.

[0124] In the physical field of a lithium-ion battery, the exchange current density, the volume fraction of lithium ions in the solid and liquid phases, and the radii of the positive and negative electrode active particles are set.

[0125] Set the potential boundary condition for the positive current density and ground the negative terminal.

[0126] In one embodiment of the present invention, the multiphysics coupled finite element simulation calculation method for the target structure battery in simulation unit 304 is as follows:

[0127] Based on the electrochemical material parameters of the positive electrode active layer and the electrolyte, the electrochemical reaction kinetic equations, charge conservation equations and mass conservation equations in the physical field of lithium-ion batteries are used to simulate and calculate the electrochemical process of the positive electrode active layer during charging and discharging, including at least the real-time lithium-ion concentration of the positive electrode active layer.

[0128] Based on the electrochemical material parameters of the negative electrode active layer and the electrolyte, the electrochemical reaction kinetic equations, charge conservation equations and mass conservation equations in the physical field of lithium-ion batteries are used to simulate and calculate the electrochemical process of the negative electrode active layer during charging and discharging, including at least the real-time lithium-ion concentration of the negative electrode active layer.

[0129] Based on the real-time lithium-ion concentration of the positive electrode active layer, the intercalation strain of the positive electrode active layer is simulated using the intercalation strain equation in the physical field of solid mechanics. At the same time, the elastic strain of the positive electrode active layer is calculated based on the mechanical parameters of the positive electrode active layer and Hooke's law.

[0130] Based on the real-time lithium-ion concentration of the negative electrode active layer, the intercalation strain of the negative electrode active layer is simulated using the intercalation strain equation in the physical field of solid mechanics. At the same time, the elastic strain of the negative electrode active layer is calculated based on the mechanical parameters of the negative electrode active layer and Hooke's law.

[0131] Based on the mechanical parameters of carbon fiber fabric current collectors and Hooke's law, the elastic strain of carbon fiber fabric current collectors is simulated and calculated.

[0132] Based on the mechanical parameters of the diaphragm and Hooke's law, the elastic strain of the diaphragm is simulated and calculated.

[0133] Determine the potential distribution and stress distribution of the target structure battery under multiple physics fields.

[0134] It should be noted that the structural energy storage integrated composite material micro-scale multiphysics coupling simulation device provided in the above embodiments is only an example of the division of the above functional units. In practical applications, the above functions can be assigned to different functional units as needed, that is, the internal structure of the device can be divided into different functional units to complete all or part of the functions described above. In addition, the above device embodiments and method embodiments belong to the same concept, and the specific implementation process can be found in the method embodiments, which will not be repeated here.

[0135] Embodiments of this application also provide a computer device, please refer to... Figure 4 The computer device includes a processor and a memory, the memory storing at least one instruction, at least one program, code set or instruction set, the at least one instruction, at least one program, code set or instruction set being loaded and executed by the processor to implement the microscale multiphysics coupling simulation method for integrated structural energy storage composite materials provided in the above method embodiments.

[0136] The embodiments of this application also provide a computer-readable storage medium storing at least one instruction, at least one program, code set, or instruction set, wherein the at least one instruction, at least one program, code set, or instruction set is loaded and executed by a processor to implement the micro-scale multiphysics coupling simulation method for integrated structural energy storage composite materials provided in the above-described method embodiments.

[0137] Embodiments of this application also provide a computer program product, which includes a computer program. A processor of a computer device reads the computer program from a computer-readable storage medium and executes the computer program, causing the computer device to perform any of the structural energy storage integrated composite material microscale multiphysics coupling simulation methods described in the above embodiments.

[0138] For ease of description, the above systems or devices are described separately as various modules or units based on their functions. Of course, in implementing this application, the functions of each unit can be implemented in one or more software and / or hardware components.

[0139] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solution of this application, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods of various embodiments or some parts of the embodiments of this application.

[0140] Finally, it should be noted that in this document, relational terms such as first, second, third, and fourth are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0141] The above are merely preferred embodiments of this application. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A multiphysics coupling simulation method at the microscale for structural energy storage integrated composite materials, characterized in that, The method includes: Obtain the characteristic dimension parameters of each part of the target structure battery; wherein, the target structure battery includes a positive electrode composed of a carbon fiber fabric current collector and a positive electrode active layer, a separator, a negative electrode composed of a carbon fiber fabric current collector and a negative electrode active layer, and an electrolyte; Based on the aforementioned characteristic size parameters, a geometric model of the target structure battery is performed, and electrochemical material parameters and mechanical parameters are assigned to each part of the geometric model respectively. Construct a lithium-ion battery physical field and a solid-state mechanical physical field containing computational functions, and set initial conditions and boundary conditions for the lithium-ion battery physical field and the solid-state mechanical physical field respectively; After meshing the geometric model, a solver is configured to update the lithium-ion concentration of the positive and negative active layers in real time using the lithium-ion battery physical field. At the same time, the solid mechanics physical field solves for the intercalation strain of the positive and negative active layers based on the lithium-ion concentration to perform multi-physics coupled finite element simulation calculation of the target structure battery.

2. The method as described in claim 1, characterized in that, The diaphragm material is woven fiberglass cloth.

3. The method as described in claim 2, characterized in that, The characteristic dimension parameters of each part of the target structure battery were obtained in the following way: The target structure battery was fabricated, and its cross-section was photographed using a super depth-of-field microscope. The cross-sectional image is analyzed using image analysis software. Based on the scaling ratio of the cross-sectional image to the target structure battery, the characteristic size parameters of each part of the target structure battery are measured and determined using the measurement tools in the image analysis software. The characteristic size parameters include at least the shape and size of the positive electrode active layer and the negative electrode active layer, the cross-sectional shape, yarn height, and yarn direction of the carbon fiber fabric current collector in the positive and negative electrodes, and the cross-sectional shape, yarn height, and yarn direction of the woven glass fiber cloth separator.

4. The method as described in claim 1, characterized in that, The process of assigning electrochemical and mechanical parameters to various parts of the geometric model includes: Electrochemical material parameters, namely maximum lithium-ion concentration and conductivity, and mechanical parameters, namely Young's modulus and Poisson's ratio, are respectively assigned to the positive electrode active layer and the negative electrode active layer; wherein the positive electrode active layer is composed of lithium nickel cobalt manganese oxide, conductive carbon black and binder, and the negative electrode active layer is composed of graphite, conductive carbon black and binder. The electrolyte is given conductivity, and the carbon fiber fabric current collector is given Young's modulus and Poisson's ratio. The diaphragm is given Young's modulus and Poisson's ratio.

5. The method according to claim 1, characterized in that, The construction of the lithium-ion battery physical field and the solid-state mechanical physical field containing the calculation function, and the setting of initial conditions and boundary conditions for the lithium-ion battery physical field and the solid-state mechanical physical field respectively, includes: Add the corresponding theoretical calculation functions for the lithium-ion battery physical field and solid mechanical physical field in the COMSOL analysis software; wherein, the lithium-ion battery physical field is based on the porous electrode theory, and the solid mechanical physical field is based on the linear elastic material theory. In the physical field of the lithium-ion battery, the exchange current density, the volume fraction of lithium ions in the solid and liquid phases, and the radii of the positive and negative electrode active particles are set. Set the potential boundary condition for the positive current density and ground the negative terminal.

6. The method according to claim 5, characterized in that, The multiphysics coupling simulation finite element method for calculating the target structure battery is as follows: Based on the electrochemical material parameters of the positive electrode active layer and the electrolyte, the electrochemical reaction kinetic equations, charge conservation equations and mass conservation equations in the physical field of the lithium-ion battery are used to simulate and calculate the electrochemical process of the positive electrode active layer during the charging and discharging process, including at least the real-time lithium-ion concentration of the positive electrode active layer. Based on the electrochemical material parameters of the negative electrode active layer and the electrolyte, the electrochemical reaction kinetic equations, charge conservation equations and mass conservation equations in the physical field of the lithium-ion battery are used to simulate and calculate the electrochemical process of the negative electrode active layer during the charging and discharging process, including at least the real-time lithium-ion concentration of the negative electrode active layer. Based on the real-time lithium-ion concentration of the positive electrode active layer, the intercalation strain of the positive electrode active layer is simulated using the intercalation strain equation in the solid mechanical physical field. At the same time, the elastic strain of the positive electrode active layer is calculated based on the mechanical parameters of the positive electrode active layer and Hooke's law. Based on the real-time lithium-ion concentration of the negative electrode active layer, the intercalation strain of the negative electrode active layer is simulated using the intercalation strain equation in the solid mechanics physical field. At the same time, the elastic strain of the negative electrode active layer is calculated based on the mechanical parameters of the negative electrode active layer and Hooke's law. Based on the mechanical parameters of the carbon fiber fabric current collector and Hooke's law, the elastic strain of the carbon fiber fabric current collector was simulated and calculated. Based on the mechanical parameters of the diaphragm and Hooke's law, the elastic strain of the diaphragm was simulated and calculated. Determine the potential distribution and stress distribution of the target structure battery under multiple physics fields.

7. A structural energy storage integrated composite material microscale multiphysics coupling simulation device, used to implement the steps of the method described in any one of claims 1-6, characterized in that, The device includes: The acquisition unit is used to acquire the characteristic size parameters of each part of the target structure battery; wherein, the target structure battery includes a positive electrode composed of a carbon fiber fabric current collector and a positive electrode active layer, a separator, a negative electrode composed of a carbon fiber fabric current collector and a negative electrode active layer, and an electrolyte; The modeling unit is used to perform geometric modeling of the target structure battery based on the feature size parameters, and to assign electrochemical material parameters and mechanical parameters to each part of the geometric model respectively; The setting unit is used to construct the lithium-ion battery physical field and the solid mechanical physical field containing the calculation function, and to set the initial conditions and boundary conditions for the lithium-ion battery physical field and the solid mechanical physical field respectively. The simulation unit is configured to perform multi-physics coupled finite element simulation calculations of the target structure battery by configuring a solver after meshing the geometric model, so that when the lithium-ion concentration of the positive electrode active layer and the negative electrode active layer is updated in real time using the lithium-ion battery physical field, the solid mechanical physical field simultaneously solves the intercalation strain of the positive electrode active layer and the negative electrode active layer based on the lithium-ion concentration.

8. A computer device, characterized in that, The computer device includes a memory and a processor. The memory is used to store computer programs, and the processor is used to execute the computer programs stored in the memory to implement the steps of the method according to any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, The storage medium stores a computer program, which, when executed by a processor, implements the steps of the method described in any one of claims 1-6.

10. A computer program product, characterized in that, Includes a computer program, which, when executed by a processor, implements the steps of the method according to any one of claims 1-6.

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