A simulation method for shock failure of lithium-ion batteries

Abstract

The present invention belongs to the field of lithium-ion battery safety research and relates to a method for simulating the impact failure of a lithium-ion battery. The method comprises the following steps: using pre-processing software to create a finite element model of the lithium-ion battery and simplifying the fine pole piece sandwich structure into a single-layer equivalent pole piece; using the stress-strain curves of materials tested in an in-plane tensile test and an out-of-plane stacked compression test, the equivalent pole piece is input into a mixed tensile-compression constitutive model and a strain-based failure model, numerically simulating the working conditions of the material mechanical property test, and calibrating the material model parameters; using the FE-SPH adaptive method to model the positive and negative electrodes of the lithium-ion battery, and using the finite element method to model the diaphragm and aluminum-plastic film, and calibrating the numerical method using force-displacement curves from quasi-static or low-speed extrusion experiments; based on this, using the numerical model constructed using the FE-SPH adaptive method to simulate the failure behavior of the lithium-ion battery under high-speed impact loads; thereby, the mechanical behavior of the lithium-ion battery impact failure can be simulated with high fidelity.

Description

Technical Field

[0001] The present invention relates to the technical field of battery safety, and in particular to a method for simulating impact failure of a lithium-ion battery. Background Art

[0002] Lithium-ion batteries have the advantages of extremely high energy density, power density, and cycle life, and have gradually become the most popular power supply equipment and are widely used in various military equipment, including: military base energy storage power stations, field power supply cabins, individual power supplies, etc. In battlefield environments, lithium-ion battery systems are extremely susceptible to various forms of extreme abuse loads, including: high and low temperatures, high humidity, exposure to sunlight and strong impact loads, which have a significant impact on the performance of lithium-ion batteries. It is well known that it is unrealistic to observe the failure process inside the battery through in-situ testing technology. Existing numerical methods are mainly dedicated to simulating the deformation behavior of lithium-ion batteries under quasi-static and low-rate conditions. At present, there is a lack of suitable simulation methods to simulate the dynamic failure behavior of lithium-ion batteries under high-speed impact. Therefore, it is extremely important to develop an impact failure simulation method for lithium-ion batteries to predict safety issues caused by mechanical abuse.

[0003] Since the existing finite element method cannot present the behavioral characteristics of active particulate matter and the mechanical contribution of the unit after failure, the impact failure simulation method of lithium-ion batteries needs to introduce the influence of the above two factors. At the same time, since the calculation of the impact dynamics model of three-dimensional lithium-ion batteries is time-consuming, it is extremely important to develop an efficient and high-fidelity lithium-ion battery impact failure simulation method. Summary of the Invention

[0004] In view of this, the present invention utilizes the advantages of numerical simulation to provide a lithium-ion battery impact failure simulation method, which can not only accurately predict the impact failure behavior of lithium-ion batteries, but also improve the model calculation efficiency.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] This embodiment provides a method for simulating impact failure of a lithium-ion battery, the method comprising:

[0007] Step 1: Use a universal tensile-compression testing machine to test the uniaxial tensile mechanical properties and stacking compression mechanical properties of the positive electrode-negative electrode-separator, and input the stress-strain curve of the material into the material card No. 124 of ANSYS LS-DYNA.

[0008] Step 2: Construct a numerical simulation model for material mechanical property testing. Compare the force-displacement curves from the numerical simulation and the experimental results to verify the input parameters for the mechanical properties of the component materials. If verification fails, re-enter the material mechanical simulation parameters. If verification passes, construct a simulation model for battery planar extrusion.

[0009] Step 3: Test the force-displacement curve of the compressed battery through indentation (spherical / blunt / conical) experiments, and construct a mechanical equivalent model of the lithium-ion battery based on the actual structure, geometric dimensions, loading method and boundary conditions of the battery in the experiment. Simplify the number of battery layers through the electrode homogenization method, divide each layer structure into a gradient finite element mesh, and apply the FE-SPH adaptive method to the positive and negative electrode sheets in the central encrypted area. In the central area, the mesh thickness of the homogenized electrode is the thickness of the electrode, and the dimensions of the mesh in the length and width directions are 1.0 to 1.2 times the mesh thickness.

[0010] Step 4: Numerical simulation is used to obtain the force-displacement curve of the battery under indentation load. This curve is compared with experimental results to verify the numerical calculation method, structural modeling method, and material model parameters. If the verification fails, re-enter the simulation parameters and debug the calculation model. If the verification passes, a numerical simulation model for high-speed impact lithium-ion batteries is constructed.

[0011] Step 5: Based on the electrode homogenization mechanical equivalent modeling method, a high-speed impact simulation model for lithium-ion batteries is constructed. Impact failure simulation requires defining the contact state within the structure, defining adhesive contact between adjacent layers and global contact between non-adjacent layers. The SPH particles in the impact failure state must define erosion contact with the finite elements of the separator.

[0012] Step 6: Based on the lithium-ion battery high-speed impact simulation model, output the damage characteristics, force-displacement curve and impact failure process of the battery impact failure.

[0013] Preferably, the lithium-ion battery structure adopts an electrode homogenization modeling method. Structurally, the sandwich structure of active layer-current collector-active layer is equivalent to a single-layer electrode structure, and the thickness of the sandwich structure is consistent with the thickness of the equivalent single-layer structure.

[0014] Preferably, the mechanical properties of the electrode material adopt a mixed tension-compression constitutive model, and the in-plane and out-of-plane directions of the equivalent electrode adopt the tensile and compressive material mechanical properties respectively. The in-plane direction characterizes the mechanical properties of the current collector, and the out-of-plane direction characterizes the mechanical properties of the active layer.

[0015] Preferably, the pole piece adopts the FE-SPH adaptive numerical calculation method, the pole piece before failure is a finite element model, and the pole piece after failure is an SPH particle model.

[0016] Preferably, the discrete layered structure of the lithium-ion battery components is meshed by three-dimensional solid units, with a gradient mesh distribution around the periphery, and the FE-SPH adaptive method is only applied to the central encrypted mesh area.

[0017] Preferably, the diaphragm material adopts the finite element method. Since the size of the diaphragm in the thickness direction is extremely small, the diaphragm finite element adopts a grid with a large aspect ratio and uses the finite element method to simulate the mechanical behavior of the diaphragm.

[0018] Preferably, the low-speed compression and high-speed impact simulations use different stress-strain material parameters, and the ultra-thin characteristics of the positive electrode, diaphragm and negative electrode materials result in significant differences in the mechanical properties of the materials in the in-plane direction and the thickness direction. Among them, the tensile behavior in the in-plane direction is dominated by the high-modulus metal current collector, while the compressive behavior in the thickness direction is mainly borne by the porous electrode coating that occupies the largest volume fraction. In the battery indentation simulation, the compression behavior dominates the mechanical response of the lithium-ion battery, and the equivalent electrode adopts a unidirectional compressive stress-strain relationship. In the battery impact simulation, the simulation model adopts a mixed tension-compression constitutive model.

[0019] Preferably, the battery component material adopts a strain-based failure criterion, and defines the minimum failure principal strain and the maximum failure principal strain through the material card MAT ADDEROSION. The minimum failure principal strain represents the compressive failure strain, and the maximum failure principal strain represents the tensile failure strain.

[0020] Preferably, the FE-SPH adaptive method defines the finite element to particle conversion through the keyword card DEFINE ADAPTIVE SOLID TOSPH, and the simulation sets the parameters ICPL=1 and IOPT=1 to respectively simulate the coupling of the newly generated SPH unit with the adjacent solid unit and the activation of the built-in SPH particles after the Lagrangian unit fails. The newly generated SPH particles are attached to the solid unit of the same component through coupling.

[0021] Preferably, the adaptive SPH particles need to follow the calculation rules of SPH. In order to avoid the discontinuity of order 0, the unit size needs to be uniformly distributed in three directions, and the ratio of the in-plane to out-of-plane unit size is set to less than 1.2 to ensure the stability of the numerical calculation.

[0022] Preferably, the equivalent positive electrode and the equivalent negative electrode are set as a set of two groups of units, the two groups of Part sets are defined as two groups of adaptive solid unit conversion particles, and the coupling contact between the particles is realized by the parameter CONT=0 in the *CONTROL_SPH card to realize particle approximate calculation.

[0023] Preferably, the component materials within the battery utilize both global and local contact. Global contact utilizes the keyword card CONTACT ERODING SINGLE SURFACE, with the soft constraint formula SOFT=2 added to the keyword. Local contact utilizes the keyword card CONTACT TIEBREAK NODES ONLY, which defines the normal and tangential adhesion forces as 0.01 MPa and adds the soft constraint formula SOFT=1. This calculates the interface stiffness using node mass and the global time step, resulting in a greater interface stiffness, which effectively handles the contact between metal and foam.

[0024] Preferably, the contact relationship between the SPH and the finite element is defined as CONTACT ERODING NODE TO SURFACE, the master segment is defined as a set of finite elements, and the slave segment is defined as a set of nodes of the SPH particles.

[0025] Preferably, the lithium-ion battery entity unit model adopts a single-point integration algorithm. Due to the combined effect of the entity unit with a large aspect ratio and the single-point integration algorithm, the numerical simulation is prone to severe high-frequency numerical oscillations. In order to avoid this phenomenon, it is necessary to define an hourglass for each entity component. The hourglass deformation and energy anomaly are suppressed by increasing viscosity or stiffness. The calculation model selects the control type of the hourglass through the parameter IHQ. For high-speed impact situations, we use viscous hourglass control parameters (type 3), which can provide the entity unit with a Flanagan-Belytschko viscosity form with accurate volume integral. For low-speed impact situations, we use rigid hourglass control parameters (type 6) to deal with soft materials such as diaphragms in batteries and units with a large aspect ratio.

[0026] An embodiment of the present application provides a method for simulating impact failure of a lithium-ion battery.

[0027] First, a finite element model of a lithium-ion battery is constructed based on the electrode homogenization method. The pre-processing requires dividing the central impact area into a fine grid. The grid size in the central area depends on the thickness of the component materials, and the grid gradually changes towards the surrounding areas. Secondly, the in-plane tensile and out-of-plane compressive stress-strain parameters of the positive electrode, negative electrode, and separator are input, and the material parameters are verified through mechanical property simulation and indentation loading battery. Then, the FE-SPH adaptive method is defined for the central failure area. This parameter sets the coupling of newly generated SPH particles with adjacent solid elements. SPH particles are not considered in the initial stage. When the finite element fails, the SPH particles are activated and participate in the calculation. In addition, a contact model for discrete layered structures is defined. Adjacent layers are defined as adhesive contact, non-adjacent layers are defined as global contact, the indenter and target plate are defined as erosion surface contact, and the SPH particles and finite elements are defined as point-to-surface contact. Finally, the calibrated model parameters are used to simulate the high-speed impact failure behavior of lithium-ion batteries.

[0028] Compared with the existing technology, it has the following beneficial effects:

[0029] 1. This invention takes into account the original characteristics of the internal battery materials after loading and the accumulation effect of failed materials, ensuring the accuracy of the mechanical simulation model to the greatest extent possible. It also considers the impact of the cross-scale characteristics of lithium-ion batteries on the computational efficiency of the three-dimensional model, mechanically equating the sandwich structure of the pole piece to a single-layer homogenized electrode structure, and applying the FE-SPH adaptive method to the pole piece. Compared with the finite element method and refined model, this method simulates the impact failure behavior of lithium-ion batteries with high fidelity and efficiency.

[0030] 2. This method verifies material mechanical properties through material mechanical property simulation and battery indentation simulation, and applies it to the impact failure behavior simulation of lithium-ion batteries. Therefore, this method is applicable to the mechanical abuse simulation of batteries under quasi-static, low-speed, and high-speed loading.

[0031] 3. The present invention constructs a finite element model of a lithium-ion battery through central area encryption, butterfly gradient meshing, and electrode homogenization methods, divides the central impacted area and the surrounding unimpacted areas into different components, and applies the FE-SPH adaptive method to the central impacted area, greatly improving the computational efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic flow chart of a method for simulating impact failure of a lithium-ion battery provided by an embodiment of the present invention;

[0033] Figure 2 A schematic diagram of an equivalent modeling method for an electrode homogenization structure provided in an embodiment of the present invention;

[0034] Figure 3A schematic diagram of battery mechanical failure simulation constructed using the FE-SPH adaptive method provided in an embodiment of the present invention;

[0035] Figure 4 A schematic diagram of a gradient finite element mesh and an SPH applied region for a lithium-ion battery provided in an embodiment of the present invention;

[0036] Figure 5 The present invention provides a comparison of the simulation results of the experiment and mechanical equivalent modeling method for impact-failed lithium-ion batteries. DETAILED DESCRIPTION

[0037] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but are not intended to limit the present invention.

[0038] This embodiment is described using commercial finite element software as an example.

[0039] See also Figure 1 The present invention provides a method for simulating the impact failure of lithium-ion batteries. The simulation process mainly includes four parts: experimental testing, verification of material mechanical performance parameters, verification of numerical calculation methods and equivalent modeling methods, and FE-SPH-based high-speed impact lithium-ion battery simulation model. Specifically:

[0040] Step 1: Test the in-plane tensile mechanical properties and out-of-plane stacking compressive mechanical properties of the positive electrode, negative electrode, and separator using a universal tensile-compression testing machine to obtain the mixed tensile-compressive stress-strain curves of the component materials;

[0041] Step 2: Construct a numerical simulation model for the material mechanical properties test, compare the force-displacement curves of the numerical simulation model and the experiment, and verify the simulation input parameters of the mechanical properties of the component materials; if the verification fails, readjust the mechanical simulation parameters of the material; if the verification passes, construct a simulation model for battery plane extrusion;

[0042] Step 3: The force-displacement curve of the compressed battery is tested through an indentation test. According to the actual structure, geometric dimensions, loading method and boundary conditions of the battery in the experiment, the electrode homogenization modeling method, the gradient finite element meshing and the FE-SPH adaptive method are combined to construct a mechanical equivalent simulation model of the battery plane extrusion. First, the number of battery layers is simplified through the electrode homogenization method, and the gradient finite element mesh is divided into each layer structure. The FE-SPH adaptive method is applied to the positive and negative electrode sheets in the central densified area. In the central area, the mesh thickness of the homogenized electrode sheet is the thickness of the electrode sheet, and the mesh length and width dimensions are 1.0 to 1.2 times the mesh thickness, and the length dimension of the mesh is equal to the thickness dimension.

[0043] Step 4: Numerical simulation is used to obtain the force-displacement curve of the battery under indentation load. This curve is compared with the experimental results to verify the simulation parameters such as the numerical calculation method, structural modeling method, and material model. If the verification fails, re-enter the simulation parameters and debug the battery plane extrusion simulation model.

[0044] Step 5: After verification, a high-speed impact simulation model of lithium-ion batteries is constructed based on the electrode homogenization mechanical equivalent modeling method;

[0045] Step 6: Based on the lithium-ion battery high-speed impact simulation model, output the damage characteristics, force-displacement curve and impact failure process of the battery impact failure.

[0046] In detail, the material mechanical properties parameters are tested through in-plane tensile mechanical properties experiments and out-of-plane compression mechanical properties experiments, and the failure parameters are verified by the material mechanical properties simulation model. Then, the electrode homogenization modeling method, mesh convergence, and battery plane extrusion simulation established by the FE-SPH adaptive method are verified and checked through the force-displacement curve of the battery plane extrusion experiment. Finally, a high-speed impact experiment of the lithium-ion battery is carried out, and the corresponding FE-SPH-based high-speed impact lithium-ion battery simulation model is constructed, and the damage characteristic parameters of the battery and the force-displacement curve of the indenter are output.

[0047] Here, the discrete layered structure of lithium-ion batteries is modeled using an electrode homogenization mechanical equivalent method. This method performs mechanical equivalence on lithium-ion batteries from three perspectives: discrete structural modeling, material mechanical properties, and numerical calculation methods. Mechanical property testing experiments are used to calibrate and verify the material model, while low-speed compression experiments are used to verify the modeling and calculation methods. The calibrated numerical model is then used to simulate the high-speed impact failure behavior of lithium-ion batteries.

[0048] In one embodiment, the simplification of the number of battery layers by the electrode homogenization method includes: applying an electrode homogenization modeling method to the lithium-ion battery structure to obtain a sandwich structure of active layer-current collector-active layer that is equivalent to a single-layer pole piece structure, wherein the thickness of the sandwich structure is consistent with the thickness of the single-layer pole piece structure.

[0049] In one embodiment, the mechanical properties of the electrode material adopt a mixed tension-compression constitutive model, and the in-plane and out-of-plane directions of the pole piece of the single-layer pole piece structure respectively adopt tensile and compressive material mechanical properties, the in-plane direction characterizes the mechanical properties of the current collector, and the out-of-plane direction characterizes the mechanical properties of the active layer.

[0050] In one embodiment, the pole piece before failure is a finite element model, and the pole piece after failure is an SPH particle model.

[0051] In one embodiment, the discrete layered structure of the lithium-ion battery is meshed by three-dimensional solid units, with a gradient mesh distribution around the periphery, and the FE-SPH adaptive method is only applied to the central encrypted mesh area.

[0052] In one embodiment, the FE-SPH adaptive method defines the finite element to particle conversion through the keyword card DEFINE ADAPTIVESOLID TO SPH, and the simulation sets the parameters ICPL=1 and IOPT=1 to respectively simulate the coupling of the newly generated SPH unit with the adjacent solid unit and the activation of the built-in SPH particles after the Lagrangian unit fails. The newly generated SPH particles are attached to the solid unit of the same component through coupling.

[0053] In one embodiment, the adaptive SPH particles follow the calculation rules of SPH. In order to avoid the discontinuity of order 0, the unit size needs to be uniformly distributed in three directions, and the ratio of the in-plane to out-of-plane unit size is set to less than 1.2 to ensure the stability of the numerical calculation.

[0054] See also Figure 2 , conventional lithium-ion batteries are composed of three main parts: positive electrode, negative electrode and separator. Among them, the positive and negative electrode sheets are composed of a current collector and active materials coated on both sides of the current collector, and the separator is a porous polymer film. The current collector of the positive electrode is aluminum foil, and the materials coated on both sides are mainly lithium oxide active materials; the current collector of the negative electrode is copper foil, and the materials coated on both sides are mainly graphite; the positive and negative electrodes are separated by a single layer of separator. For a full-size battery cell, the number of grids in its refined model can reach tens of millions. The huge number of grids and extremely small unit size will cause a sharp drop in computational efficiency. In order to improve computational efficiency, the present invention adopts an electrode homogenization equivalence method to equate the sandwich composite structure of the electrode sheet (active coating-current collector-active coating) to a single-layer structure, and its thickness is the sum of the sub-layer materials.

[0055] See also Figure 3Lithium-ion batteries feature multi-material and multi-layer structures. Under high-speed impact, the crushed material within the battery can produce a significant accumulation effect. Traditional finite element methods achieve numerical stability by deleting elements, but this ignores the secondary loading of the failed material on the structure and cannot reproduce the crushing phenomenon of the impacted material. To overcome the numerical limitations caused by element deletion, this paper employs a finite element-smoothed particle adaptive method. This method combines the advantages of the finite element method and the SPH particle method, avoiding numerical voids while simulating the behavior of the failed material. Within the entire battery, the electrode sheet, separator, and aluminum-plastic film occupy approximately 80%, 15%, and 5% of the volume, respectively. Clearly, the electrode sheet occupies the largest volume fraction, and its post-failure behavior cannot be ignored. The electrode sheet is composed of a metal current collector and active particles adhered to its upper and lower surfaces. The granular active layer cannot withstand tensile loads, while the metal current collector in the interlayer provides the electrode sheet with resistance to tensile deformation. Taking these two factors into account, we employ the FE-SPH adaptive method in our computational model to simulate the crushing behavior of an equivalent electrode sheet. Because the separator's thickness dimensions are extremely small, solid elements with large aspect ratios are not suitable for the SPH method. Unlike the active layer and current collector, which have mechanical properties, the separator and aluminum-plastic film are plastic materials and do not experience significant shattering after impact. Therefore, the FEM method was used for the separator and aluminum-plastic film.

[0056] High-speed impacts cause electrode failure, which is then converted into SPH particles. These particles remain active within the integration region, and their stress state and contact behavior remain unchanged. Consequently, the failed fragments accumulated within the battery can withstand compressive loads and transfer energy to the outside. The failed material continuously compresses component materials in areas not directly impacted, simulating the structural response of lithium-ion batteries under high-speed impact.

[0057] See also Figure 4 The cell size in the center of the lithium-ion battery is 0.2 × 0.2 mm, and gradually transitions to 0.4 mm from the center to the edges, using a butterfly mesh as the transition. Furthermore, due to the localized effects of high-speed impact, the material suffers severe damage only in the center, so the FE-SPH adaptive method is applied only to this region.

[0058] The following is a comparison between the high-speed impact simulation output results and the experimental results through a specific embodiment, as follows:

[0059] Based on a simulation method for lithium-ion battery impact failure provided by the present invention, the electrode homogenization mechanical equivalent modeling method therein simulates a 9mm bullet penetrating a soft-pack battery at a speed of 360m / s.

[0060] The simulation results are shown in Table 1, which shows that the diameter of the bullet entrance is 9.13mm, the diameter of the through hole at the exit is 24.48mm, the maximum expansion diameter is 30.44mm, and the maximum expansion thickness is 15.28mm. As shown in the table below, compared with the experimental results and the results of the conventional method, the simulation model established by the conventional method cannot reproduce the expansion diameter and expansion thickness of the battery. However, the electrode homogenization mechanical equivalent modeling method used in this patent accurately reproduces the expansion size of the battery, which shows that the simulation method proposed in this patent can effectively simulate the impact failure behavior of the battery.

[0061]

[0062] Table 1

[0063] Further, to illustrate the advantages of this method, Figure 5 The simulation method proposed in this patent demonstrates a high-fidelity simulation of the experimental battery failure process during impact. The simulation results reproduce the impact fragmentation behavior of a lithium-ion battery. At 68μs, the bullet's head is about to penetrate the back of the lithium-ion battery, and the aluminum-plastic film reaches its deformation limit, with a rupture in the center. At 116μs, the bullet's continued forward motion causes the rupture area of ​​the aluminum-plastic film to increase, and the fragmented material within is about to be ejected from the battery. At 232μs, the bullet has completely exited the lithium-ion battery, and the aluminum-plastic film exhibits a "petal-like" outward-turning morphology. The bullet's inertia causes the fragments within to continuously eject forward and spread in all directions, forming a structural characteristic similar to a debris cloud. At 284μs, the debris cloud expands, with relatively sparse fragments at the front and denser fragments at the rear. The simulation results clearly identify the fragments within the lithium-ion battery. Small SPH particles represent the equivalent electrode that has reached its deformation limit, while large fragments represent the aluminum-plastic film and separator. The different size classes of fragments are determined by the properties of the component materials.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements and improvements made within the spirit and scope of the present invention are included in the scope of protection of the present invention.

Claims

1. A method for simulating impact failure of a lithium-ion battery, characterized in that: The method comprises: Step 1: Test the in-plane tensile mechanical properties and out-of-plane stacking compressive mechanical properties of the positive electrode, negative electrode, and separator using a universal tensile-compression testing machine to obtain the mixed tensile-compressive stress-strain curves of the component materials; Step 2: Construct a numerical simulation model for the material mechanical properties test, compare the force-displacement curves of the numerical simulation model and the experiment, and verify the simulation input parameters of the mechanical properties of the component materials; if the verification fails, readjust the mechanical simulation parameters of the material; if the verification passes, construct a simulation model for battery plane extrusion; Step 3: The force-displacement curve of the compressed battery is tested through an indentation test. According to the actual structure, geometric dimensions, loading method and boundary conditions of the battery in the experiment, the electrode homogenization modeling method, the gradient finite element meshing and the FE-SPH adaptive method are combined to construct a mechanical equivalent simulation model of the battery plane extrusion. First, the number of battery layers is simplified through the electrode homogenization method, and the gradient finite element mesh is divided into each layer structure. The FE-SPH adaptive method is applied to the positive and negative electrode sheets in the central densified area. In the central area, the mesh thickness of the homogenized electrode sheet is the thickness of the electrode sheet, and the mesh length and width dimensions are 1.0 to 1.2 times the mesh thickness, and the length dimension of the mesh is equal to the thickness dimension. Step 4: Numerical simulation is used to obtain the force-displacement curve of the battery under indentation load, and the curve is compared with the experiment to verify the numerical calculation method, structural modeling method, and material model simulation parameters. If the verification fails, re-enter the simulation parameters and debug the battery plane extrusion simulation model. Step 5: After verification, a high-speed impact simulation model of lithium-ion batteries is constructed based on the electrode homogenization mechanical equivalent modeling method; Step 6: Based on the lithium-ion battery high-speed impact simulation model, output the damage characteristics, force-displacement curve and impact failure process of the battery impact failure.

2. The method for simulating impact failure of a lithium-ion battery according to claim 1, wherein: The method of simplifying the number of battery layers through electrode homogenization includes: applying an electrode homogenization modeling method to the lithium-ion battery structure to obtain a sandwich structure of active layer-current collector-active layer that is equivalent to a single-layer pole piece structure, wherein the thickness of the sandwich structure is consistent with the thickness of the single-layer pole piece structure.

3. The method for simulating impact failure of a lithium-ion battery according to claim 2, wherein: The mechanical properties of the electrode material adopt a mixed tension-compression constitutive model. The in-plane and out-of-plane directions of the pole piece of the single-layer pole piece structure respectively adopt tensile and compressive material mechanical properties. The in-plane direction characterizes the mechanical properties of the current collector, and the out-of-plane direction characterizes the mechanical properties of the active layer.

4. The method for simulating impact failure of a lithium-ion battery according to claim 1, wherein: The single-layer pole piece structure adopts the FE-SPH adaptive numerical calculation method, the pole piece before failure is a finite element model, and the pole piece after failure is an SPH particle model.

5. The method for simulating impact failure of a lithium-ion battery according to claim 1, wherein: The discrete layered structure of the lithium-ion battery is meshed by three-dimensional solid units, with a gradient mesh distribution around the periphery, and the FE-SPH adaptive method is only applied to the central encrypted mesh area.

6. The method for simulating impact failure of a lithium-ion battery according to claim 1, wherein: The FE-SPH adaptive method defines the finite element to particle conversion through the keyword card DEFINE ADAPTIVE SOLID TO SPH. The simulation sets the parameters ICPL=1 and IOPT=1 to simulate the coupling of the newly generated SPH unit with the adjacent solid unit and the activation of the built-in SPH particles after the Lagrangian unit fails, respectively. The newly generated SPH particles are attached to the solid unit of the same component through coupling.

7. The method for simulating impact failure of a lithium-ion battery according to claim 6, wherein: The adaptive SPH particles follow the calculation rules of SPH. In order to avoid the discontinuity of order 0, the unit sizes need to be uniformly distributed in three directions, and the ratio of the in-plane to out-of-plane unit sizes is set to less than 1.2 to ensure the stability of the numerical calculation.

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