A method and system for constructing a multi-scale electrochemical-thermal-mechanical coupling model of a lithium ion battery
By constructing a multi-scale electrochemical-thermal-mechanical coupling model, the prediction bias problem of existing lithium-ion battery modeling under high rate and complex operating conditions is solved, realizing bidirectional feedback between the micro and meso scales, and improving the prediction accuracy and safety of batteries under high rate and dynamic operating conditions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHONGQING UNIV OF TECH
- Filing Date
- 2026-06-05
- Publication Date
- 2026-08-04
AI Technical Summary
Existing lithium-ion battery modeling methods struggle to accurately capture microscopic physical changes under high-rate and complex operating conditions, neglect the impact of stress feedback on lithium-ion diffusion behavior, and lack cross-scale synergy capabilities. This results in large deviations in voltage and temperature rise predictions, making it difficult to reveal the underlying mechanisms of decreased utilization of active materials and mechanical damage.
A multi-scale electrochemical-thermal-mechanical coupling model is constructed. By coupling three-dimensional micromechanical sub-models, one-dimensional mesoscopic electrochemical models and three-dimensional macroscopic thermal models across scales, a stress feedback mechanism is introduced to achieve bidirectional feedback between the micro and mesoscopic levels, thereby correcting electrochemical kinetic parameters and heat transfer parameters and establishing a cross-scale closed-loop coupling system.
It significantly reduced the prediction bias of voltage and temperature rise under high rate and dynamic operating conditions, revealed the intrinsic link between surface stress concentration and the decline in the utilization rate of active materials, broke through the limitations of traditional macroscopic homogenization models, and provided a more reliable basis for battery thermal safety management and life prediction.
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Figure CN122333826B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of lithium-ion battery modeling and simulation technology, and relates to a method and system for constructing a multi-scale electrochemical-thermal-mechanical coupling model of lithium-ion batteries. Background Technology
[0002] As the core energy unit for new energy vehicles, energy storage systems, and high-power electronic devices, lithium-ion batteries are subject to profound regulation of their macroscopic electrothermal behavior by complex internal electrochemical reaction processes and mechanical evolution. With the development of batteries towards higher energy density, higher charge / discharge rates, and more complex dynamic operating conditions, problems such as concentration gradients, local polarization, diffusion-induced stress, and non-uniform temperature distribution caused by lithium-ion insertion / extraction within the battery are becoming increasingly prominent. Especially in cylindrical batteries, the microscopic particle state exhibits stronger coupling characteristics with the macroscopic temperature field and voltage response due to the influence of the winding structure, radial heat transfer path, and boundary heat dissipation conditions.
[0003] Currently, existing lithium-ion battery modeling methods mainly include: Classical pseudo-two-dimensional (P2D) model: based on porous electrode theory and concentrated solution theory, used to describe the electrochemical kinetics inside the battery.
[0004] Reduced-order model (ROM): A simplified model for real-time online estimation of battery management systems.
[0005] Three-dimensional electrochemical-thermal coupling model: used to analyze the local non-uniform thermal evolution of large-size pouch or cylindrical batteries.
[0006] Unidirectional mechanics and aging model: Analysis of particle concentration polarization and diffusion-induced stress.
[0007] While the above models can describe some of the battery's operating characteristics at their respective levels, they still have significant limitations when dealing with high-rate and complex operating conditions: Limited microscopic characterization: Traditional macroscopic models are mostly based on homogenization assumptions and lack detailed characterization of microscopic dynamic mechanisms such as non-uniform distribution of active particle concentration, surface stress concentration, and local mechanical distortion. This makes it difficult to accurately capture drastic microscopic physical changes under complex dynamic conditions such as high-rate fast charging, low temperature and high internal resistance, and NEDC and DST, resulting in large deviations in voltage and temperature rise predictions.
[0008] Lack of stress feedback: Most existing electrochemical-mechanical coupling studies only treat stress as a result of the electrochemical process and solve it in a one-way manner. This one-way coupling ignores the reverse modulation effect of micro-stress accumulation on local lithium-ion diffusion behavior, charge transfer barrier and kinetic parameters, and therefore it is difficult to reveal the intrinsic mechanism of surface stress concentration leading to decreased utilization of active materials, performance degradation and mechanical damage under high-rate conditions.
[0009] Poor cross-scale coordination capability: Existing models generally lack a cross-scale real-time coordination mapping mechanism from microscopic particles and mesoscopic electrodes to macroscopic cells. Concentration polarization, diffusion-induced stress, and local damage behavior at the particle level cannot be effectively transferred to the overall battery terminal voltage response and three-dimensional thermal distribution, limiting the prediction accuracy and robustness of the model under extreme conditions.
[0010] Therefore, there is an urgent need to establish a multi-scale electrochemical-thermal-mechanical coupling analysis method that covers microscopic particles, mesoscopic electrodes and macroscopic monomers, and to break through the cross-scale barrier between microscopic mechanical damage and macroscopic monomer electrothermal response by introducing a bidirectional feedback mechanism. Summary of the Invention
[0011] In view of this, the purpose of this invention is to provide a method and system for constructing a multi-scale electrochemical-thermal-mechanical coupling model for lithium-ion batteries.
[0012] To achieve the above objectives, the present invention provides the following technical solution: A method for constructing a multi-scale electrochemical-thermal-mechanical coupling model for lithium-ion batteries, the method comprising the following steps: Step 1: Construct a three-dimensional micromechanical sub-model to characterize the concentration distribution and diffusion-induced stress evolution inside the negative electrode active particles during the lithium-ion intercalation / deintercalation process, and obtain the stress concentration variables on the surface region of the active particles. Step 2: Construct a one-dimensional mesoscopic electrochemical model to characterize lithium-ion transport, potential distribution, and interfacial reaction kinetics in the positive electrode region, electrolyte region, and negative electrode region. The one-dimensional mesoscopic electrochemical model and the three-dimensional micromechanical sub-model are bidirectionally coupled through a stress feedback mechanism. The stress variables are output from the three-dimensional micromechanical sub-model to the one-dimensional mesoscopic electrochemical model to correct the electrochemical kinetic parameters. Step 3: Construct a three-dimensional macroscopic thermal model to characterize the temperature field distribution and thermal gradient evolution inside and on the outer surface of a cylindrical lithium-ion battery cell. Step four: Establish a cross-scale closed-loop coupling system. The one-dimensional mesoscopic electrochemical model inputs the calculated reaction heat, ohmic heat, and reversible heat as heat source terms into the three-dimensional macroscopic thermal model. The three-dimensional macroscopic thermal model feeds back the calculated temperature field distribution to the one-dimensional mesoscopic electrochemical model to correct the mass and heat transfer parameters, thereby achieving real-time collaborative solution at three scales: microscopic active particles, mesoscopic porous electrodes, and macroscopic battery cells.
[0013] Furthermore, in step two, the stress feedback mechanism specifically involves using the stress state inside the active particles as a feedback variable to act on the lithium-ion diffusion behavior and the interface charge transfer reaction process. By changing the mass transfer capacity and reaction rate of the surface region of the active particles, the utilization rate of local active materials and the overall terminal voltage response are adjusted.
[0014] Furthermore, in step one, the three-dimensional micromechanical sub-model obtains the lithium-ion concentration distribution inside the active particles by solving the solid-phase diffusion equation. And calculate the diffusion-induced stress based on the concentration gradient. The formula is expressed as:
[0015] in, For Young's modulus, Poisson's ratio, For strain tensor, For partial molar volume, This represents the initial solid-phase lithium ion concentration. For Kroneck's symbol.
[0016] Furthermore, in step two, the one-dimensional mesoscopic electrochemical model is constructed based on the Porous Electrode Theory (PET) and the Concentrated Solution Theory (CST) to solve for the concentration of lithium ions in the liquid phase. Liquid phase potential Solid-state potential and solid-liquid interface current density .
[0017] Furthermore, the modified electrochemical kinetic parameters include a diffusion coefficient that takes into account stress effects. and reaction rate constant Its expression is:
[0018]
[0019] in, The negative electrode reference solid-phase diffusion coefficient is used. For reference temperature, For coupling temperature, For diffusion activation energy, The activation energy of the reaction. Let be the ideal gas constant. The stress feedback coupling coefficient is... The stress feedback coupling coefficient is... For the equivalent stress inside the particle, This refers to the equivalent stress on the particle surface. Furthermore, in step three, the three-dimensional macroscopic thermodynamic model describes the heat transfer process of the cylindrical lithium-ion battery cell using an energy conservation equation, expressed as follows:
[0020] in, The average density of the battery. For specific heat capacity, Let thermal conductivity tensor be the thermal conductivity tensor. The total heat production rate is the input from the one-dimensional mesoscopic electrochemical model.
[0021] Furthermore, step four also includes: setting radial heat transfer paths and boundary heat dissipation conditions based on the winding structure of the cylindrical lithium-ion battery cell, thereby characterizing the non-uniform thermal gradient distribution.
[0022] A multi-scale electrochemical-thermal-mechanical coupling system for lithium-ion batteries constructed using the method described above, the system comprising: The microscopic calculation module is used to perform calculations on the three-dimensional micromechanical sub-model and output the stress field and concentration field of the active particles. The mesoscopic calculation module is used to perform calculations of the one-dimensional mesoscopic electrochemical model, and correct the kinetic process according to the stress variables input by the microscopic calculation module, and output the battery terminal voltage and heat generation term; The macroscopic calculation module is used to perform calculations of the three-dimensional macroscopic thermodynamic model, output a three-dimensional temperature field based on the heat generation term input by the mesoscopic calculation module, and feed the three-dimensional temperature field back to the mesoscopic calculation module.
[0023] Furthermore, the system also includes a data comparison module, which is used to compare the experimental test terminal voltage and temperature data under different discharge rates and ambient temperature conditions with the simulation results output by the system in real time, so as to verify the prediction accuracy of the model.
[0024] Furthermore, the system also includes a damage assessment module, which is used to assess the mechanical damage and thermal runaway risk of the cylindrical lithium-ion battery cell under dynamic operating conditions by analyzing the stress concentration values of the particle surface region output by the microscopic calculation module and the radial and axial temperature distribution characteristics output by the macroscopic calculation module.
[0025] The beneficial effects of this invention are as follows: (1) By introducing a two-way feedback mechanism of microparticles and mesoscopic electrochemistry, the prediction deviation of voltage and temperature rise under high rate and dynamic conditions (such as DST conditions) is significantly reduced.
[0026] (2) It can reveal the intrinsic relationship between surface stress concentration at the micro level and the decrease in utilization rate and performance degradation of active materials at the macro level.
[0027] (3) It breaks through the limitations of the traditional macroscopic homogenization model and can effectively capture the non-uniform thermal gradient distribution under low temperature environment and complex heat dissipation conditions.
[0028] (4) It provides a more reliable theoretical basis for thermal safety management, structural optimization design and life prediction of cylindrical lithium-ion batteries.
[0029] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description
[0030] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein: Figure 1 A schematic diagram of a multi-scale, multi-physics coupling framework; Figure 2 The experimental and simulated terminal voltages are compared under different discharge rates; (a) is the result of the traditional model without the microparticle feedback mechanism, and (b) is the result of the model of this invention with the microparticle feedback mechanism. Figure 3 Figure 1 shows the temperature fitting results for the DST operating condition under dynamic conditions; (a) shows the results without a microscale model, (b) shows the results with a microscale feedback model, (c) shows the fitting error between the simulation and experimental results of the battery surface temperature under the DST operating condition without a microscale model, (d) shows the input current under the DST operating condition with a microscale model, (e) shows the simulation and experimental fitting results of the battery surface temperature under the DST operating condition with a microscale model, and (f) shows the fitting error between the simulation and experimental results of the battery surface temperature under the DST operating condition with a microscale model. Figure 4 The following are the particle stress distribution diagrams at the end of discharge under different discharge rates; (a) is the three-dimensional stress distribution diagram at a discharge rate of 0.5C; (b) is the three-dimensional stress distribution diagram at a discharge rate of 1C; (c) is the three-dimensional stress distribution diagram at a discharge rate of 2C; and (d) is the three-dimensional stress distribution diagram at a discharge rate of 3C. Figure 5The following are the battery temperature distribution diagrams at the end of discharge under different discharge rates: (a) is the three-dimensional temperature distribution diagram at a discharge rate of 0.5C; (b) is the three-dimensional temperature distribution diagram at a discharge rate of 1C; (c) is the three-dimensional temperature distribution diagram at a discharge rate of 2C; and (d) is the three-dimensional temperature distribution diagram at a discharge rate of 3C. Detailed Implementation
[0031] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.
[0032] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.
[0033] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.
[0034] Example 1 This embodiment details a method for constructing a multi-scale electrochemical-thermal-mechanical coupling model for lithium-ion batteries and its application under constant current discharge conditions.
[0035] The model construction process is as follows: First, a three-dimensional micromechanical sub-model is constructed. This model focuses on representative active particles within the negative electrode region to characterize the non-uniform concentration distribution caused by solid-phase lithium-ion insertion / extraction. The lithium-ion concentration distribution within the active particles is obtained by solving the solid-phase diffusion equation. Furthermore, the diffusion-induced stress caused by the concentration gradient was calculated. This model focuses on characterizing the stress concentration phenomenon on the surface of active particles, providing a basis for subsequent kinetic corrections.
[0036] Secondly, a one-dimensional mesoscopic electrochemical model is constructed. This model is based on porous electrode theory and concentrated solution theory, covering the positive electrode region, electrolyte region, and negative electrode region. In this embodiment, the coupling between the microscopic and mesoscopic dimensions is achieved through a stress feedback mechanism. The stress variable output by the micromechanical sub-model modulates the diffusion coefficient in the reverse direction. and reaction rate constant Isoelectric kinetic parameters. The specific kinetic correction formulas are as follows:
[0037]
[0038] in, The negative electrode reference solid-phase diffusion coefficient is used. For reference temperature, For coupling temperature, For diffusion activation energy, The activation energy of the reaction. Let be the ideal gas constant. The stress feedback coupling coefficient is... The stress feedback coupling coefficient is... For the equivalent stress inside the particle, This refers to the equivalent stress on the particle surface. Subsequently, a three-dimensional macroscopic thermal model was constructed. This model is designed for the wound structure of a cylindrical lithium-ion battery cell, taking into account the radial heat transfer path and boundary heat dissipation conditions.
[0039] Finally, a multi-scale closed-loop coupled system is established. The heat generation term calculated by the mesoscopic model is used as the heat source input to the macroscopic thermal model, while the temperature field distribution output by the macroscopic thermal model is fed back to the mesoscopic model in real time to correct the mass and heat transfer related parameters.
[0040] like Figure 1 As shown, the multi-scale multiphysics coupling framework illustrates the interaction paths across the three scales mentioned above. The figure clearly illustrates the transmission relationships of concentration distribution, stress variables, temperature variables, and heat source types across different scales, constituting the core technical feature of this invention.
[0041] like Figure 2 As shown in the figure, this embodiment experimentally verified the terminal voltage of the cylindrical battery at different discharge rates. Figure 2In the diagram, (a) represents the results of the traditional model without the microparticle feedback mechanism, and (b) represents the results of the model of this invention with the microparticle feedback mechanism. The comparison shows that the multi-scale coupled model including the microparticle sub-model can more accurately fit the battery terminal voltage changes at different discharge rates, verifying the accuracy of the stress feedback mechanism under static conditions.
[0042] Example 2 This embodiment illustrates the operation process of the model of the present invention under dynamic operating conditions (DST conditions) and its analysis of damage evolution.
[0043] Under DST dynamic load conditions, the current fluctuates drastically over time. The workflow of this embodiment is as follows: The mesoscopic electrochemical model receives dynamic current input in real time. Due to the drastic changes in current, intense concentration gradient fluctuations occur within the microscopic active particles. The three-dimensional micromechanical sub-model calculates and updates the stress concentration state on the particle surface in real time.
[0044] Stress variables are fed back to the electrochemical kinetic equations in real time, correcting the mass transfer and reactivity of the active particle surface. This two-way feedback allows the model to capture the decrease in active material utilization caused by stress concentration at high magnification.
[0045] like Figure 3 The figure shows the temperature fitting results under DST conditions. The results demonstrate that this invention significantly reduces the temperature rise prediction error under dynamic load through the synergy of microscopic and mesoscopic models. (a) represents the input current under DST conditions without a microscopic model; (b) represents the simulation and experimental fitting results of the battery surface temperature under DST conditions without a microscopic model; (c) represents the fitting error of the simulation and experimental results of the battery surface temperature under DST conditions without a microscopic model; (d) represents the input current under DST conditions with a microscopic model; (e) represents the simulation and experimental fitting results of the battery surface temperature under DST conditions with a microscopic model; and (f) represents the fitting error of the simulation and experimental results of the battery surface temperature under DST conditions with a microscopic model. like Figure 4 As shown, (a) is the three-dimensional stress distribution map at a discharge rate of 0.5C; (b) is the three-dimensional stress distribution map at a discharge rate of 1C; (c) is the three-dimensional stress distribution map at a discharge rate of 2C; and (d) is the three-dimensional stress distribution map at a discharge rate of 3C. The model further outputs the internal stress distribution maps of the particles at the end of discharge under different discharge rates. It can be seen that as the discharge rate increases, the stress level in the particle surface area increases significantly, and the high-stress area is concentrated near the particle surface. This provides an intuitive basis for assessing battery mechanical damage.
[0046] like Figure 5As shown, (a) is the three-dimensional temperature distribution map at a discharge rate of 0.5C; (b) is the three-dimensional temperature distribution map at a discharge rate of 1C; (c) is the three-dimensional temperature distribution map at a discharge rate of 2C; and (d) is the three-dimensional temperature distribution map at a discharge rate of 3C. The model simultaneously outputs the three-dimensional temperature distribution map of the cylindrical battery cell. At higher discharge rates, the battery exhibits obvious non-uniform thermal distribution characteristics along both the radial and axial directions.
[0047] Through dynamic simulation in this embodiment, the present invention achieves cross-scale synergistic characterization from particle-level concentration polarization and diffusion-induced stress to overall battery terminal voltage and three-dimensional thermal distribution.
[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.
Claims
1. A method for constructing a multi-scale electrochemical-thermal-mechanical coupling model for lithium-ion batteries, characterized in that: The method includes the following steps: Step 1: Construct a three-dimensional micromechanical sub-model to characterize the concentration distribution and diffusion-induced stress evolution within the negative electrode active particles during the lithium-ion intercalation / deintercalation process, and obtain the stress concentration variables on the surface region of the active particles; the three-dimensional micromechanical sub-model obtains the lithium-ion concentration distribution within the active particles by solving the solid-phase diffusion equation. And calculate the diffusion-induced stress based on the concentration gradient. The formula is expressed as: in, For Young's modulus, Poisson's ratio, For strain tensor, For partial molar volume, This represents the initial solid-phase lithium ion concentration. The symbol for Kronecker; Step two involves constructing a one-dimensional mesoscopic electrochemical model to characterize lithium-ion transport, potential distribution, and interfacial reaction kinetics in the positive electrode region, electrolyte region, and negative electrode region. This one-dimensional mesoscopic electrochemical model is bidirectionally coupled to the three-dimensional micromechanical sub-model via a stress feedback mechanism. The stress variables output from the three-dimensional micromechanical sub-model are fed back to the one-dimensional mesoscopic electrochemical model to correct the electrochemical kinetic parameters. The corrected electrochemical kinetic parameters include a diffusion coefficient that considers stress effects. and reaction rate constant Its expression is: in, The negative electrode reference solid-phase diffusion coefficient is used. For reference temperature, For coupling temperature, For diffusion activation energy, The activation energy of the reaction. Let be the ideal gas constant. The stress feedback coupling coefficient is... The stress feedback coupling coefficient is... For the equivalent stress inside the particle, Equivalent stress on particle surface; Step 3: Construct a three-dimensional macroscopic thermal model to characterize the temperature field distribution and thermal gradient evolution inside and on the outer surface of a cylindrical lithium-ion battery cell. Step four: Establish a cross-scale closed-loop coupling system. The one-dimensional mesoscopic electrochemical model inputs the calculated reaction heat, ohmic heat, and reversible heat as heat source terms into the three-dimensional macroscopic thermal model. The three-dimensional macroscopic thermal model feeds back the calculated temperature field distribution to the one-dimensional mesoscopic electrochemical model to correct the mass and heat transfer parameters, thereby achieving real-time collaborative solution at three scales: microscopic active particles, mesoscopic porous electrodes, and macroscopic battery cells.
2. The method for constructing a multi-scale electrochemical-thermo-mechanical coupling model of a lithium-ion battery according to claim 1, characterized in that: In step two, the stress feedback mechanism specifically involves using the stress state inside the active particles as a feedback variable to act on the lithium-ion diffusion behavior and the interface charge transfer reaction process. By changing the mass transfer capacity and reaction rate of the surface region of the active particles, the utilization rate of local active materials and the overall terminal voltage response are adjusted.
3. The method for constructing a multi-scale electrochemical-thermal-mechanical coupling model of a lithium-ion battery according to claim 1, characterized in that: In step two, the one-dimensional mesoscopic electrochemical model is constructed based on the porous electrode theory (PET) and the concentrated solution theory (CST) to solve for the liquid-phase lithium-ion concentration. Liquid phase potential Solid-state potential and solid-liquid interface current density .
4. The method for constructing a multi-scale electrochemical-thermal-mechanical coupling model of a lithium-ion battery according to claim 1, wherein its features are as follows: The key feature is that, in step three, the three-dimensional macroscopic thermodynamic model describes the heat transfer process of the cylindrical lithium-ion battery cell using the energy conservation equation, expressed as follows: in, The average density of the battery. For specific heat capacity, Let thermal conductivity tensor be the thermal conductivity tensor. The total heat production rate is the input from the one-dimensional mesoscopic electrochemical model.
5. The method for constructing a multi-scale electrochemical-thermal-mechanical coupling model of a lithium-ion battery according to claim 1, characterized in that: Step four further includes: setting radial heat transfer paths and boundary heat dissipation conditions based on the winding structure of the cylindrical lithium-ion battery cell, thereby characterizing the non-uniform thermal gradient distribution.
6. A multi-scale electrochemical-thermal-mechanical coupling system for lithium-ion batteries constructed using the method described in any one of claims 1 to 5, characterized in that: The system includes: The microscopic calculation module is used to perform calculations on the three-dimensional micromechanical sub-model and output the stress field and concentration field of the active particles. The mesoscopic calculation module is used to perform calculations of the one-dimensional mesoscopic electrochemical model, and correct the kinetic process according to the stress variables input by the microscopic calculation module, and output the battery terminal voltage and heat generation term; The macroscopic calculation module is used to perform calculations of the three-dimensional macroscopic thermodynamic model, output a three-dimensional temperature field based on the heat generation term input by the mesoscopic calculation module, and feed the three-dimensional temperature field back to the mesoscopic calculation module.
7. The multi-scale electrochemical-thermal-mechanical coupling system for lithium-ion batteries according to claim 6, characterized in that: The system also includes a data comparison module, which is used to compare the experimental test terminal voltage and temperature data under different discharge rates and ambient temperature conditions with the simulation results output by the system in real time, so as to verify the prediction accuracy of the model.
8. The multi-scale electrochemical-thermal-mechanical coupling system for lithium-ion batteries according to claim 7, characterized in that: The system also includes a damage assessment module, which is used to assess the mechanical damage and thermal runaway risk of the cylindrical lithium-ion battery cell under dynamic operating conditions by analyzing the stress concentration values of the particle surface region output by the microscopic calculation module and the radial and axial temperature distribution characteristics output by the macroscopic calculation module.