Drop evaluation method and device for power battery, vehicle and storage medium

Abstract

The application relates to a power battery drop evaluation method and device, a vehicle and a storage medium, wherein the method comprises the following steps: constructing a drop simulation grid model of a power battery based on a preset construction rule, determining material properties of all components in the power battery; determining a contact connection relationship of a drop simulation working condition of the power battery, and setting a boundary and a load of the drop simulation working condition of the power battery; performing drop simulation simulation of the power battery by using the drop simulation grid model of the power battery, the material properties, the contact connection relationship, the boundary and the load, obtaining simulation simulation data, and evaluating the strength performance and the safety performance of the power battery under the drop working condition according to the simulation data. Therefore, the problems in the prior art that the structural coverage and the refinement degree of the simulation model are insufficient, the stress deformation and the contact of the internal structural parts of the power battery are not considered, calculation deviation occurs, and it is difficult to meet the strength and safety performance evaluation requirements of the power battery under the drop working condition are solved.

Description

Technical Field

[0001] This application relates to the field of power battery technology, and in particular to a method, apparatus, vehicle, and storage medium for evaluating the drop performance of a power battery. Background Technology

[0002] Currently, power batteries serve as the core energy supply component for emerging mobility tools such as new energy vehicles, drones, and low-altitude aircraft, resulting in a huge market for their applications. This massive demand continuously drives the rapid upgrading and iteration of power battery products. The main directions of iteration fall into two categories: performance improvement (such as energy density) and safety improvement (no fire, no explosion). Safety indicators represent the lower limit for power battery products and must meet certain requirements. As the application scenarios for power batteries expand, new operating conditions are constantly emerging, which need to be fully identified and considered during product development from the initial design stage. Drop conditions are one such example, including drops during battery hoisting, drops during battery swapping, and accidental drops from low-altitude aircraft, requiring assurance of the power battery's safety performance under these drop conditions.

[0003] In related technologies, a virtual battery pack is constructed to simulate the drop process, and the relative displacement and maximum stress of each structure are extracted to determine whether the safety threshold is met. Alternatively, dynamic simulation parameters are set to simulate the drop process, and the accuracy of the simulation is verified by comparing the simulation data with the measured data.

[0004] However, in related technologies, due to insufficient structural coverage and refinement of simulation models, detailed modeling of the complete main structure and weld structure of the power battery is not performed. This results in the failure to consider the stress deformation and contact of the internal structural components of the power battery, leading to calculation deviations. Furthermore, a finite element simulation analysis and evaluation system for power battery drop has not been established, which cannot meet the strength and safety performance assessment requirements of power batteries under drop conditions and urgently needs improvement. Summary of the Invention

[0005] This application provides a method, device, vehicle, and storage medium for evaluating the drop performance of power batteries, in order to solve the problems in related technologies where the structural coverage and refinement of simulation models are insufficient, resulting in calculation deviations due to the failure to consider the stress deformation and contact of internal structural components of the power battery, and the lack of a finite element simulation analysis and evaluation system for power battery drop performance, making it difficult to meet the strength and safety performance evaluation requirements of power batteries under drop conditions.

[0006] The first aspect of this application provides a method for evaluating the drop performance of a power battery, comprising the following steps: constructing a drop simulation mesh model of the power battery based on preset construction rules, and determining the material properties of all components in the power battery; determining the contact connection relationships of the power battery drop simulation conditions, and setting the boundaries and loads of the power battery drop simulation conditions; performing a drop simulation of the power battery using the drop simulation mesh model, material properties, contact connection relationships, boundaries, and loads to obtain simulation data, and evaluating the strength performance and safety performance of the power battery under drop conditions based on the simulation data.

[0007] Through the above-mentioned technical means, the embodiments of this application can establish a non-interference, key structure-refined drop simulation mesh model of the power battery according to the construction rules, accurately assign material properties to all components, and set contact connection relationships, boundaries and loads that conform to physical reality, so as to realize the simulation of the drop condition of the power battery, thereby analyzing and evaluating the strength performance and safety performance of the power battery under the drop condition, so as to guide and optimize the structural design of the power battery, improve the strength and safety performance of the power battery, and effectively improve R&D efficiency and reduce R&D costs.

[0008] Optionally, in one embodiment of this application, the preset construction rules include: the drop simulation mesh model includes at least a main structure mesh model and a rigid surface; there is no interference between all mesh models in the drop simulation mesh model; the size of the rigid surface is larger than the size of the power battery, and the distance between the edge of the power battery and the edge of the rigid surface is greater than a preset threshold; the rigid surface is arranged parallel to the bottom protective plate of the power battery, and the gap between the rigid surface and the lowest point of the bottom of the power battery is within a preset range; a solid weld mesh model is established at each welded connection of the lower housing assembly of the power battery.

[0009] Through the above-mentioned technical means, the embodiments of this application can require the model to include the main structural mesh and rigid surfaces without interference, while clearly defining the size, relative position, gap of the rigid surfaces and the solid weld mesh model of each welded connection of the lower box assembly, thereby ensuring the structural integrity and geometric rationality of the simulation mesh model, avoiding calculation errors caused by inaccurate penetration and contact detection, and accurately simulating and capturing the stress at each welded connection of the lower box assembly.

[0010] Optionally, in one embodiment of this application, the preset construction rules include: the extracted mid-surface of the plate structure of the power battery is divided into shell units, and the main mesh type of the plate structure is quadrilateral; the box welding assembly and cell module of the power battery are divided into hexahedral meshes.

[0011] Through the above-mentioned technical means, the embodiments of this application can divide the core surface of the plate structure into shell units mainly composed of quadrilaterals, while the lower box welding assembly and the cell module adopt hexahedral mesh, thereby adapting to the mechanical properties and morphological characteristics of different structures, taking into account both simulation accuracy and simulation calculation efficiency, and optimizing simulation performance.

[0012] Optionally, in one embodiment of this application, determining the material properties of all components in the power battery includes: determining the density, elastic modulus, and Poisson's ratio of the material properties of all components; and determining the material plasticity of the lower casing, bottom protective plate, liquid cooling plate, and cell shell of all components.

[0013] Through the above-mentioned technical means, the embodiments of this application can determine the basic mechanical parameters of density, elastic modulus, and Poisson's ratio of all components in the power battery, and assign material plasticity parameters to core main structural components such as the lower casing and bottom guard plate, thereby enabling the realistic simulation of the deformation of the structure under strong impact from a drop, improving the matching degree between material properties and actual drop conditions, and ensuring the authenticity of simulation data.

[0014] Optionally, in one embodiment of this application, setting the boundaries and loads of the power battery drop simulation condition includes: determining the final drop velocity of the power battery based on the initial drop velocity and the drop height to define an initial step; calculating the time step of the power battery drop simulation condition based on the final drop velocity to define a load step; and setting the boundaries and loads according to the initial step and the load step.

[0015] Through the above-mentioned technical means, the embodiments of this application can determine the final drop velocity from the initial drop velocity and the drop height to define the initial step, and calculate the time step of the power battery drop simulation condition based on the final drop velocity to define the load step. This achieves refined boundary and load settings for the power battery drop simulation condition, improves computational efficiency, ensures the physical accuracy of the initial impact conditions, and makes the subsequent solution process stable and the results reliable.

[0016] Optionally, in one embodiment of this application, evaluating the strength and safety performance of the power battery under drop conditions based on the simulation data includes: determining the structural stress of the lower housing assembly of the power battery based on the simulation data; calculating the deformation of the power battery; and determining the strength and safety performance based on the structural stress of the lower housing assembly and the deformation.

[0017] Through the above-mentioned technical means, the embodiments of this application can extract the structural stress of the lower housing assembly of the power battery based on simulation data, and calculate the overall and local deformation to evaluate the strength performance and safety performance. This allows for the simultaneous determination of whether the lower housing assembly is broken and whether the deformation is too large, leading to safety hazards such as cell fire or explosion. This provides clear indicators for the quantitative determination of the drop safety of power batteries.

[0018] A second aspect of this application provides a drop evaluation device for a power battery, comprising: a determination module, configured to construct a drop simulation mesh model of the power battery based on preset construction rules, and determine the material properties of all components in the power battery; a setting module, configured to determine the contact connection relationship of the power battery drop simulation condition, and set the boundary and load of the power battery drop simulation condition; and an evaluation module, configured to perform a drop simulation of the power battery using the drop simulation mesh model, material properties, contact connection relationship, boundary and load, to obtain simulation data, and evaluate the strength performance and safety performance of the power battery under drop conditions based on the simulation data.

[0019] Through the above-mentioned technical means, the embodiments of this application can establish a non-interference, key structure-refined drop simulation mesh model of the power battery according to the construction rules, accurately assign material properties to all components, and set contact connection relationships, boundaries and loads that conform to physical reality, so as to realize the simulation of the drop condition of the power battery, thereby analyzing and evaluating the strength performance and safety performance of the power battery under the drop condition, so as to guide and optimize the structural design of the power battery, improve the strength and safety performance of the power battery, and effectively improve R&D efficiency and reduce R&D costs.

[0020] Optionally, in one embodiment of this application, the preset construction rules include: the drop simulation mesh model includes at least a main structure mesh model and a rigid surface; there is no interference between all mesh models in the drop simulation mesh model; the size of the rigid surface is larger than the size of the power battery, and the distance between the edge of the power battery and the edge of the rigid surface is greater than a preset threshold; the rigid surface is arranged parallel to the bottom protective plate of the power battery, and the gap between the rigid surface and the lowest point of the bottom of the power battery is within a preset range; a solid weld mesh model is established at each welded connection of the lower housing assembly of the power battery.

[0021] Through the above-mentioned technical means, the embodiments of this application can require the model to include the main structural mesh and rigid surfaces without interference, while clearly defining the size, relative position, gap of the rigid surfaces and the solid weld mesh model of each welded connection of the lower box assembly, thereby ensuring the structural integrity and geometric rationality of the simulation mesh model, avoiding calculation errors caused by inaccurate penetration and contact detection, and accurately simulating and capturing the stress at each welded connection of the lower box assembly.

[0022] Optionally, in one embodiment of this application, the preset construction rules include: the extracted mid-surface of the plate structure of the power battery is divided into shell units, and the main mesh type of the plate structure is quadrilateral; the box welding assembly and cell module of the power battery are divided into hexahedral meshes.

[0023] Through the above-mentioned technical means, the embodiments of this application can divide the core surface of the plate structure into shell units mainly composed of quadrilaterals, while the lower box welding assembly and the cell module adopt hexahedral mesh, thereby adapting to the mechanical properties and morphological characteristics of different structures, taking into account both simulation accuracy and simulation calculation efficiency, and optimizing simulation performance.

[0024] Optionally, in one embodiment of this application, the setting module includes: a first determining unit, used to determine the density, elastic modulus, and Poisson's ratio information of the material properties of all components; and a second determining unit, used to determine the material plasticity of the lower housing, bottom protective plate, liquid cooling plate, and cell shell of all components.

[0025] Through the above-mentioned technical means, the embodiments of this application can determine the basic mechanical parameters of density, elastic modulus, and Poisson's ratio of all components in the power battery, and assign material plasticity parameters to core main structural components such as the lower casing and bottom guard plate, thereby enabling the realistic simulation of the deformation of the structure under strong impact from a drop, improving the matching degree between material properties and actual drop conditions, and ensuring the authenticity of simulation data.

[0026] Optionally, in one embodiment of this application, the setting module includes: a third determining unit, configured to determine the final drop velocity of the power battery based on the initial drop velocity and the drop height, to define an initial step; a first calculating unit, configured to calculate the time step of the drop simulation condition of the power battery based on the final drop velocity, to define a load step; and a setting unit, configured to set the boundary and the load according to the initial step and the load step.

[0027] Through the above-mentioned technical means, the embodiments of this application can determine the final drop velocity from the initial drop velocity and the drop height to define the initial step, and calculate the time step of the power battery drop simulation condition based on the final drop velocity to define the load step. This achieves refined boundary and load settings for the power battery drop simulation condition, improves computational efficiency, ensures the physical accuracy of the initial impact conditions, and makes the subsequent solution process stable and the results reliable.

[0028] Optionally, in one embodiment of this application, the evaluation module includes: a fourth determining unit, used to determine the structural stress of the lower housing assembly of the power battery based on the simulation data; a second calculation unit, used to calculate the deformation of the power battery; and a fifth determining unit, used to determine the strength performance and the safety performance based on the structural stress of the lower housing assembly and the deformation.

[0029] Through the above-mentioned technical means, the embodiments of this application can extract the structural stress of the lower housing assembly of the power battery based on simulation data, and calculate the overall and local deformation to evaluate the strength performance and safety performance. This allows for the simultaneous determination of whether the lower housing assembly is broken and whether the deformation is too large, leading to safety hazards such as cell fire or explosion. This provides clear indicators for the quantitative determination of the drop safety of power batteries.

[0030] A third aspect of this application provides a vehicle, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the drop evaluation method for a power battery as described in the above embodiments.

[0031] A fourth aspect of this application provides a non-volatile computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described drop evaluation method for a power battery.

[0032] A fifth aspect of this application provides a computer program product that stores a computer program that, when executed by a processor, implements the above-described method for evaluating the drop performance of a power battery.

[0033] This application's embodiments can establish a non-interference, finely detailed drop simulation mesh model of a power battery based on construction rules. It accurately assigns material properties to all components and sets contact connections, boundaries, and loads that conform to physical reality, thereby simulating the drop conditions of the power battery. This allows for the analysis and evaluation of the power battery's strength and safety performance under drop conditions, guiding and optimizing the power battery's structural design, improving its strength and safety performance, and effectively increasing R&D efficiency while reducing R&D costs. This solves the problems in related technologies where insufficient structural coverage and detail in the simulation model leads to calculation errors due to the failure to consider the stress deformation and contact of internal structural components of the power battery, and the lack of a comprehensive finite element simulation analysis and evaluation system for power battery drop tests, making it difficult to meet the strength and safety performance assessment requirements of power batteries under drop conditions.

[0034] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0035] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a flowchart of a drop evaluation method for a power battery according to an embodiment of this application; Figure 2 This is a flowchart of a drop evaluation method for a power battery according to an embodiment of this application; Figure 3 This is a schematic diagram of a power battery pack and rigid surface modeling according to an embodiment of this application; Figure 4 This is a schematic diagram of the solid mesh of the lower box beam and frame weld seam according to an embodiment of this application; Figure 5 This is a schematic diagram of an RBE2 (Rigid Body Element 2) unit connection according to an embodiment of this application; Figure 6 This is a schematic diagram of a drop evaluation device for a power battery according to an embodiment of this application; Figure 7 This is a structural schematic diagram of a vehicle provided according to an embodiment of this application.

[0036] Figure label: 10-Drop evaluation device for power batteries; 100-Determination module, 200-Setting module, 300-Evaluation module; 701-Memory, 702-Processor, 703-Communication interface. Detailed Implementation

[0037] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0038] The following description, with reference to the accompanying drawings, outlines a method, apparatus, vehicle, and storage medium for evaluating the drop performance of a power battery according to embodiments of this application. Addressing the issues raised in the background section regarding insufficient structural coverage and refinement of simulation models, which fail to consider the stress, deformation, and contact of internal structural components of the power battery, leading to calculation errors, and the lack of a comprehensive finite element simulation analysis and evaluation system for power battery drop performance, this application provides a method for evaluating the drop performance of power batteries under drop conditions. This method establishes a non-interference, finely detailed drop simulation mesh model of the power battery based on construction rules, accurately assigns material properties to all components, and sets contact connections, boundaries, and loads that conform to physical reality. This allows for the simulation of power battery drop conditions, thereby analyzing and evaluating the strength and safety performance of the power battery under drop conditions. This guides and optimizes the structural design of the power battery, improves its strength and safety performance, and effectively enhances R&D efficiency while reducing R&D costs. This solves the problems in related technologies, such as insufficient structural coverage and refinement of simulation models, which fail to consider the stress deformation and contact of internal structural components of the power battery, leading to calculation errors, and the lack of a finite element simulation analysis and evaluation system for power battery drops, making it difficult to meet the strength and safety performance evaluation requirements of power batteries under drop conditions.

[0039] Specifically, Figure 1 This is a schematic flowchart of a drop evaluation method for a power battery provided in an embodiment of this application.

[0040] like Figure 1 As shown, the drop evaluation method for this power battery includes the following steps: In step S101, a drop simulation mesh model of the power battery is constructed based on preset construction rules to determine the material properties of all components in the power battery.

[0041] It is understood that the preset construction rules in this application embodiment can be interpreted as pre-defined standards for establishing mesh models, including specific indicators such as mesh type selection, size control, and geometric integrity requirements. These preset construction rules can be set by those skilled in the art according to actual conditions, and no specific restrictions are imposed here. The drop simulation mesh model can be understood as transforming the physical structure of the power battery into a mesh element model usable for finite element analysis. Material properties may include density, elastic modulus, and Poisson's ratio information.

[0042] For example, in this embodiment of the application, based on the actual physical structure and size parameters of the power battery, combined with preset construction rules, finite element analysis software is used to process the geometric features and mesh the various structures of the power battery to build a drop simulation mesh model consistent with the actual structure; then, through material testing and material database retrieval, the basic mechanical parameters of the materials of each component of the power battery are obtained, and the determination and assignment of the material properties of all components are completed. Among them, the density of components other than the battery cell adopts the measured value, and the battery cell density is calculated in reverse to make the total mass of the model equal to the total mass of the actual object.

[0043] The embodiments of this application can construct a drop simulation mesh model of a power battery by building rules and determine the material properties of all components in the power battery, providing a reliable foundation for subsequent drop simulation and significantly improving the calculation accuracy and the reliability of the results.

[0044] In step S102, the contact connection relationship of the power battery drop simulation condition is determined, and the boundary and load of the power battery drop simulation condition are set.

[0045] It is understood that the contact connection relationship in the embodiments of this application can be understood as the mechanical relationship of contact, collision and connection between the various components of the power battery and between the power battery and the rigid surface during the drop; the boundary and load may include constraint conditions, initial velocity field, gravitational acceleration and external forces during the drop.

[0046] In actual implementation, this embodiment combines the actual structure of the power battery, clarifies the actual connection methods such as welding, bolting, and snap-fit ​​between various components, as well as the contact form between the power battery and the rigid surface, defines the contact type in the finite element software, and sets the friction coefficient and connection constraints that match the actual situation to determine the complete contact connection relationship; then, based on the motion characteristics and force conditions of actual drop scenarios such as power battery hoisting and battery swapping, the software applies boundary conditions such as fixed constraints to the rigid surface, applies gravity loads and inertial loads corresponding to the initial drop velocity to the power battery, and adjusts the specific values ​​of the boundaries and loads according to parameters such as drop height and initial velocity to ensure a high degree of matching with the actual drop conditions.

[0047] Specifically, the power battery drop simulation involves three types of contact connections: TIE connection, general contact, and RBE2 binding. TIE connection is a binding constraint used to permanently bind the contact surfaces or nodes of two independent meshes together, simulating an ideal connection with no relative sliding or separation. It is commonly used to simulate non-removable connections such as welding and adhesive bonding. General contact automatically detects all possible contact surfaces in the model and handles mutual penetration. It is suitable for drop collisions with unpredictable deformation, avoiding numerical penetration due to missed contact pairs, and realistically simulating battery-ground collisions and secondary contacts caused by large deformations of internal components. RBE2 binding couples a master node (independent node) to multiple slave nodes (nodes around bolt holes), maintaining a rigid displacement relationship (no relative motion) between the slave nodes and the master node. It is commonly used to simulate bolted connections without actually creating a bolt thread mesh.

[0048] Inside the power battery, the upper housing, liquid cooling plate, bottom protective plate and lower housing are bolted together. Instead of creating bolt entities, RBE2 binding connections are created at the bolt holes. The horizontal and vertical beams and frame of the lower housing are connected by welding. TIE connections are created only on the solid weld mesh model to bind the welded parts. At the same time, a general contact is created to define the collision between the battery and the rigid surface and the contact between various parts that may occur due to deformation during the drop.

[0049] The embodiments of this application can determine the contact connection relationship of the power battery drop simulation condition and set the boundary and load of the power battery drop simulation condition, thereby achieving accurate restoration of the actual mechanical environment of the power battery drop and avoiding the mechanical response deviation in the simulation process caused by incorrect definition of contact connection relationship and improper setting of boundary load, thus ensuring the authenticity and effectiveness of subsequent drop simulation.

[0050] In step S103, the drop simulation mesh model, material properties, contact connection relationship, boundary and load of the power battery are used to simulate the drop of the power battery to obtain simulation data, and the strength performance and safety performance of the power battery under drop conditions are evaluated based on the simulation data.

[0051] It is understood that, in the embodiments of this application, strength performance can be understood as the ability of each structure of the power battery to resist deformation, damage, and yielding under drop impact load, which is a core indicator for measuring the mechanical reliability of the battery structure. Safety performance can be understood as the ability of each structure of the power battery to avoid safety hazards such as failure, rupture, and leakage under drop conditions.

[0052] In actual implementation, the embodiments of this application can perform drop simulation of power batteries based on the drop simulation mesh model, material properties, contact connection relationship, boundary and load, and use finite element software to perform explicit dynamic solution. The output results include at least stress and plastic strain.

[0053] For example, in this embodiment, the drop simulation mesh model, material properties, contact connection relationships, boundaries, and loads of the power battery can be input into an explicit dynamic solver for calculation. The solver uses the central difference method to update the nodal acceleration, velocity, and displacement step by step. The output results include the stress, strain, and displacement curves and contour maps of each component over time, with a focus on extracting the maximum structural stress of the lower housing assembly and calculating the plastic deformation of the battery pack as a whole and key areas. Furthermore, based on the safety threshold of the power battery structural design, the tensile strength of the materials, and relevant industry standards, the simulation data is systematically and quantitatively analyzed to determine whether the power battery meets the usage requirements under drop conditions from both strength and safety dimensions.

[0054] The embodiments of this application can perform drop simulation of power batteries and evaluate the strength and safety performance of power batteries under drop conditions based on the simulation data. This realizes digital simulation of the drop process of power batteries and quantitative evaluation of their performance, reduces R&D testing costs, and provides a quantitative reference for battery structure optimization.

[0055] Optionally, in one embodiment of this application, the preset construction rules include: the drop simulation mesh model includes at least a main structure mesh model and a rigid surface; there is no interference between all mesh models in the drop simulation mesh model; the size of the rigid surface is larger than the size of the power battery, and the distance between the power battery frame and the edge of the rigid surface is greater than a preset threshold; the rigid surface is set parallel to the bottom protection plate of the power battery, and the gap between the rigid surface and the lowest point of the bottom of the power battery is within a preset range; a solid weld mesh model is established at each welded connection of the lower housing assembly of the power battery.

[0056] It is understood that the main structure in this application embodiment may include, but is not limited to, an upper housing, a lower housing, a cell module, a liquid cooling plate, and a bottom protective plate. A rigid surface can be understood as representing the ground or an impact platform, used to simulate a real drop. A preset threshold can be 50mm; this preset threshold can be set by those skilled in the art according to actual conditions, and is not specifically limited here. A preset range can be (0mm, 1mm); this preset range can be set by those skilled in the art according to actual conditions, and is not specifically limited here. The welded connections of the lower housing assembly can refer to the parts where the components of the lower housing of the power battery are connected by welding. A solid weld mesh model can be understood as a solid mesh model built according to the actual weld size and shape at the welded connection points, used to restore the actual physical structure of the weld.

[0057] In actual implementation, the embodiments of this application can establish a mesh model of the main structure of the power battery (upper housing, lower housing assembly, cell module assembly, liquid cooling plate, bottom protective plate, etc.) and rigid surfaces, while other components of the power battery can be established as needed. At the same time, it is necessary to ensure that all mesh models are free from interference.

[0058] Furthermore, in this embodiment, the rigid surface needs to be larger than the power battery, and the distance between the power battery frame and the edge of the rigid surface should not be less than 50mm. The rigid surface needs to be parallel to the bottom cover plate of the power battery, and the gap between it and the lowest point of the bottom of the power battery is S, which requires 0mm < S < 1mm, and a recommended value of S is 0.2mm; a solid weld mesh model needs to be established at each welded connection of the lower housing assembly.

[0059] Specifically, the entire process of power battery drop simulation is as follows: the power battery falls from a height to the ground, causing a collision. After the collision, the power battery deforms, and the deformation causes previously non-contact components to come into contact. The upper casing, lower casing, cell module, liquid cooling plate, and bottom protective plate are the main load-bearing and protective components, and complete modeling is required to accurately simulate the real physical response. Rigid surfaces represent the ground or impact platform, used to simulate a real drop. It is essential to ensure that all mesh models are free of interference; mesh interference can cause initial penetration and contact algorithm errors, directly leading to calculation divergence or distorted results.

[0060] In this embodiment, the rigid surface is larger than the battery, and the frame is ≥50mm from the edge. This ensures that the battery lands entirely within the rigid surface during a drop, preventing the battery edge from being suspended or partially contacted due to insufficient rigidity, which could cause localized stress concentration or non-realistic tipping and lead to contact failure. The rigid surface needs to be parallel to the bottom protective plate of the power battery, and the gap S between it and the lowest point of the bottom of the power battery needs to be positive (>0) to prevent initial penetration; at the same time, S<1 mm ensures timely contact detection. If the gap is too large, the battery will only make contact after freefalling a certain distance, which will change the initial collision velocity S. An excessively large gap will delay the contact trigger time and produce errors.

[0061] In this embodiment, the weld is a geometrical discontinuity and potential failure zone in the structure. During a drop test, the weld may experience high stress, leading to plastic deformation or even fracture. Simplified shell elements cannot accurately simulate the local thickness-direction stress and multiaxial stress state of the weld, while a solid weld mesh model can preserve the actual geometry and material properties of the weld. Furthermore, the material properties and stiffness of the weld differ from those of the base material; ignoring the weld would overestimate the structural strength and lead to incorrect failure location predictions. A solid weld mesh model can realistically simulate the stress transfer, plastic deformation, and fracture risk of the weld.

[0062] The embodiments of this application can require the model to include a main structural mesh and rigid surfaces without interference, while specifying the size, relative position, gap of the rigid surfaces and the solid weld mesh model of each welded connection of the lower box assembly, thereby ensuring the structural integrity and geometric rationality of the simulation mesh model, avoiding calculation errors caused by inaccurate penetration and contact detection, and accurately simulating and capturing the stress at each welded connection of the lower box assembly.

[0063] Optionally, in one embodiment of this application, the preset construction rules include: the extracted mid-surface of the plate structure of the power battery is divided into shell units, and the main mesh type of the plate structure is quadrilateral; the box welding assembly and cell module of the power battery are divided into hexahedral meshes.

[0064] It is understood that the plate-like structure in the embodiments of this application may include an upper box, a bottom protective plate, and a liquid cooling plate. A shell element can be understood as an element with in-plane stiffness and bending stiffness, and the nodal degrees of freedom include translation and rotation.

[0065] In actual implementation, this embodiment of the application can divide the plate-like structure (upper casing, bottom protective plate, liquid cooling plate) into shell units by extracting the mid-surface. The main grid type is quadrilateral, with triangles accounting for less than 1%, and the grid size is 4~8mm. The lower casing welding assembly and the cell module are required to be divided into hexahedral grids with a grid size of 4~8mm. The grid type is not mandatory for other components, only the grid size of 1~8mm is required.

[0066] Specifically, plate structures are thin-walled structures with a thickness much smaller than the planar dimensions. Shell elements are efficient and accurate in calculation, and can accurately simulate bending and buckling deformation. Quadrilateral meshes have much better continuity and convergence in stress calculation than triangular meshes. An excessively high proportion of triangles can cause stress distortion and result fluctuations. Triangles are used to help divide the bending parts of plate structures, avoiding excessive local stiffness or accuracy deterioration.

[0067] In the simulation of power battery drop, the lower casing and cell module are the core load-bearing components, which are subjected to strong compression and impact. Therefore, using a hexahedral mesh can improve the accuracy of stress calculation and the realism of deformation simulation. The mesh type is not mandatory for other components, thus avoiding the waste of computing resources.

[0068] In this embodiment, the extracted surface of the plate structure can be divided into shell units mainly composed of quadrilaterals, while the lower box welding assembly and the cell module are made of hexahedral mesh, thereby adapting to the mechanical properties and morphological features of different structures, taking into account both simulation accuracy and simulation calculation efficiency, and optimizing simulation performance.

[0069] Optionally, in one embodiment of this application, determining the material properties of all components in the power battery includes: determining the density, elastic modulus, and Poisson's ratio of the material properties of all components; and determining the material plasticity of the lower casing, bottom protective plate, liquid cooling plate, and cell shell of all components.

[0070] It is understood that, in the embodiments of this application, material plasticity can be understood as the characteristic of a material to undergo irreversible permanent deformation after the stress exceeds the yield limit.

[0071] In actual implementation, the embodiments of this application can determine the material properties of all components, including density, elastic modulus, and Poisson's ratio. Except for the battery cell, the density of each component is assigned according to the measured value; the battery cell density is back-calculated so that the total mass of the entire mesh model equals the total mass of the actual object. At the same time, the main structural components such as the lower casing, bottom protective plate, liquid cooling plate, and battery cell shell are additionally assigned material plasticity, while other components may not be assigned material plasticity if there is no analysis requirement.

[0072] The embodiments of this application can determine the basic mechanical parameters of density, elastic modulus, and Poisson's ratio of all components in the power battery, and assign material plasticity parameters to core main structural components such as the lower housing and bottom guard plate. This enables the realistic simulation of the deformation of the structure under strong impact from a drop, improves the matching degree between material properties and actual drop conditions, and ensures the authenticity of the simulation data.

[0073] Optionally, in one embodiment of this application, setting the boundaries and loads of the power battery drop simulation condition includes: determining the final drop velocity of the power battery based on the initial drop velocity and the drop height to define an initial step; calculating the time step of the power battery drop simulation condition based on the final drop velocity to define a load step; and setting the boundaries and loads according to the initial step and the load step.

[0074] It is understood that the initial step in the embodiments of this application can be understood as the first analysis step of the simulation calculation, in which the battery is given an initial velocity and subjected to gravity; the load step can be understood as the subsequent analysis step, used to calculate the control of the contact process.

[0075] In actual implementation, the embodiments of this application can define the final drop velocity of the power battery pack, define 1 to 6 degrees of freedom with full constraints for the rigid surface, and set one initial step and one load step.

[0076] Specifically, the initial step is the final fall velocity, which is given by the formula v. 2 =v0 2 +2gh is calculated, where v is the final velocity of the fall, v0 is the initial velocity of the fall (depending on the specific working conditions, usually 0), g is the gravitational acceleration, and h is the fall height; During the load step, fully constrained rigid surfaces with degrees of freedom 1-6 are required. This includes activating the large deformation switch during simulation, as the component undergoes significant deformation. The time step is set to 10t, derived from S = vt + 1 / 2gt. 2 The calculation yields (since time t is on the order of small magnitude, the formula can be simplified to S=vt), where S is the reserved gap value, v is the final velocity of the fall, g is the acceleration due to gravity, and t is time, thus calculating the time step. To balance accuracy and efficiency, mass scaling needs to be defined, requiring a stable time step of at least 1e-7s.

[0077] The embodiments of this application can determine the final drop velocity from the initial drop velocity and the drop height to define the initial step, and calculate the time step of the power battery drop simulation condition based on the final drop velocity to define the load step. This achieves refined boundary and load settings for the power battery drop simulation condition, improves computational efficiency, ensures the physical accuracy of the initial impact conditions, and makes the subsequent solution process stable and the results reliable.

[0078] Optionally, in one embodiment of this application, evaluating the strength and safety performance of the power battery under drop conditions based on simulation data includes: determining the structural stress of the lower housing assembly of the power battery based on simulation data; calculating the deformation of the power battery; and determining the strength and safety performance based on the structural stress and deformation of the lower housing assembly.

[0079] It is understood that the structural stress of the lower housing assembly in this embodiment can be interpreted as the mechanical stress experienced by various parts of the lower housing assembly during the drop simulation. As the core load-bearing structure at the bottom of the battery, the stress state of the lower housing assembly directly reflects the battery's impact resistance. The deformation can be understood as the displacement and deformation values ​​of various structures of the power battery during the drop simulation.

[0080] In actual implementation, the drop test evaluation requirements for power batteries in this application embodiment may include two items: first, the structural stress of the lower battery housing assembly must be less than the material strength limit, and fracture is not allowed; second, the deformation of the battery cell must be controlled within a safe range, with specific limits implemented according to the requirements of the battery cell manufacturer. If there are no explicit requirements, the plastic strain of the battery cell shall not exceed 1 / 2 of the material's elongation at fracture. Both of the above indicators must be met simultaneously.

[0081] For example, this application embodiment can determine the structural stress of the lower housing assembly of the power battery based on simulation data. Then, the maximum stress value of the lower housing assembly is compared with the ultimate tensile strength of the structural material to determine whether the structure has yielded or failed, thereby evaluating the strength performance of the power battery. The lower housing is the skeleton of the battery pack; if it fractures, the internal cells will lose protection, high-voltage lines will be exposed or even detached, potentially causing short circuits and fires. This application embodiment uses the ultimate tensile strength of the material as the critical value, which is the basic minimum requirement for structural safety.

[0082] When a battery cell is subjected to compression or bending deformation during a drop, excessive plastic strain may cause the diaphragm to rupture, the positive and negative electrodes to come into contact, or an internal short circuit, which could lead to thermal runaway. However, battery cells typically allow for a certain degree of elastic deformation or even minor plastic deformation. In this application, the embodiment uses a plastic strain of the battery cell not exceeding 1 / 2 of the material's elongation at break as a safety threshold, which avoids oversensitivity while ensuring sufficient safety.

[0083] The embodiments of this application can extract the structural stress of the lower housing assembly of the power battery based on simulation data, and calculate the overall and local deformation to evaluate the strength and safety performance. This allows for the simultaneous determination of whether the lower housing assembly is broken and whether the deformation is too large, leading to safety hazards such as cell fire or explosion. This provides clear indicators for the quantitative assessment of the drop safety of power batteries.

[0084] Specifically, it can be combined with Figures 2 to 5 As shown, the working principle of the drop evaluation method for power batteries in this application is explained in detail with a specific embodiment.

[0085] like Figure 2 As shown, embodiments of this application may include the following steps: Step S201: Establishment of the power battery drop simulation mesh model.

[0086] In this embodiment, a mesh model of the main structure of the power battery (upper housing, lower housing assembly, cell module assembly, liquid cooling plate, bottom protective plate, etc.) and rigid surfaces can be established. All mesh models are free from interference.

[0087] like Figure 3 As shown in the embodiment of this application, the rigid surface is larger than the power battery, and the distance between the power battery frame and the edge of the rigid surface is 50mm. The rigid surface is parallel to the bottom protective plate of the power battery, and the gap between it and the lowest point of the bottom of the power battery is S=0.2mm.

[0088] like Figure 4 As shown, taking the welding joints of the lower box beams and frame as an example, a solid weld mesh model must be created for all welding joints of the lower box assembly components.

[0089] In terms of mesh division, the plate-like structures (upper housing, bottom protective plate, liquid cooling plate) are divided into shell units by extracting the middle surface, mainly quadrilaterals, with triangles accounting for less than 1%, and the mesh size is controlled between 4 and 8 mm; the lower housing welding assembly and the cell module adopt hexahedral mesh, with a size of 4 to 8 mm; the mesh type of other components is not limited, and the size is in the range of 1 to 8 mm.

[0090] Step S202: Define material properties.

[0091] In this embodiment, the material properties of all components can be determined, including density, elastic modulus, and Poisson's ratio. The cell density is calculated inversely to ensure that the total mass of the entire mesh model equals the total mass of the physical object. Furthermore, additional material plasticity is applied to the main structural components such as the lower casing, bottom protective plate, liquid cooling plate, and cell housing.

[0092] Step S203: Setting the contact connection relationship for the power battery drop simulation condition.

[0093] In this embodiment, the contact connection relationship of the power battery drop simulation condition can be set, and the contact connection includes: TIE connection, general contact, and RBE2 binding.

[0094] like Figure 5 As shown, the upper housing, liquid cooling plate, and bottom protective plate inside the power battery are bolted to the lower housing. Instead of creating bolts, RBE2 binding connections are created at the bolt holes. The horizontal and vertical beams and frame of the lower housing are connected by welding. TIE connections are created only on the solid weld mesh model to bind the welded components. At the same time, a general contact is created to define the collision between the battery and the rigid surface, as well as the contact between various components that may occur due to deformation during the drop.

[0095] Step S204: Define the boundary and load of the power battery drop simulation condition.

[0096] In this embodiment, the final drop velocity of the power battery pack can be defined, and 1-6 degrees of freedom with full constraints can be defined for the rigid surface. This embodiment sets up an initial step and a load step. The initial step defines the final drop velocity, the value of which is given by the formula v2=v0. 2 Calculations using +2gh show that in this example, v0 is 0 mm / s², and g is the acceleration due to gravity, taken as 9800 mm / s². 2 h is the drop height, which is 10000mm in this embodiment. The velocity v is calculated to be 14000mm / s.

[0097] In this embodiment, the rigid surface is fully constrained for 1-6 degrees of freedom during the load step, and the large deformation switch is activated. The time step is set to 10t, derived from S=vt+1 / 2gt. 2Calculations show that, since the time t is on the order of small magnitude, the formula simplifies to S=vt, where S is 0.2 mm and v is 14000 mm / s. Solving for t, we get t≈1.43e-5 s, so the time step is set to 1.43e-4 s. To balance accuracy and efficiency, mass scaling is defined to control the stable time step to be no less than 1e-7 s.

[0098] Step S205: Output control and calculation solution.

[0099] In this embodiment, stress and plastic strain can be output and explicit dynamic solutions can be obtained using finite element software.

[0100] Step S206: Result evaluation.

[0101] The evaluation indicators in this application embodiment include two aspects: first, the structural stress of the lower housing assembly must be less than the material strength limit and fracture is not allowed; the maximum stress of the lower housing in this application embodiment meets this requirement; second, the cell deformation must be controlled within a safe range, with specific limits implemented according to the cell manufacturer's requirements. If no explicit requirements are specified, the evaluation is based on the cell's plastic strain not exceeding 1 / 2 of the material's elongation at break. The cell's plastic strain in this application embodiment exceeds this limit and does not meet the requirements. Since both indicators are not simultaneously met, the strength and safety performance of the power battery under drop conditions are deemed unqualified, and structural optimization is required.

[0102] The drop evaluation method for power batteries proposed in this application can establish a non-interference, finely detailed drop simulation mesh model of the power battery based on construction rules. It accurately assigns material properties to all components and sets contact connections, boundaries, and loads that conform to physical reality, thereby simulating the drop conditions of the power battery. This allows for the analysis and evaluation of the strength and safety performance of the power battery under drop conditions, guiding and optimizing the structural design of the power battery, improving its strength and safety performance, and effectively increasing R&D efficiency and reducing R&D costs. This solves the problems in related technologies where insufficient structural coverage and detail in the simulation model leads to calculation errors due to the failure to consider the stress deformation and contact of internal structural components of the power battery, and the lack of a finite element simulation analysis and evaluation system for power battery drop tests, making it difficult to meet the strength and safety performance evaluation requirements of power batteries under drop conditions.

[0103] Next, referring to the accompanying drawings, a drop evaluation device for a power battery according to an embodiment of this application is described.

[0104] Figure 6 This is a schematic diagram of the structure of the drop evaluation device for a power battery according to an embodiment of this application.

[0105] like Figure 6As shown, the drop evaluation device 10 for power batteries includes: a determination module 100, a setting module 200, and an evaluation module 300.

[0106] The determination module 100 is used to construct a drop simulation mesh model of the power battery based on preset construction rules and to determine the material properties of all components in the power battery.

[0107] The setting module 200 is used to determine the contact connection relationship of the power battery drop simulation condition, and to set the boundary and load of the power battery drop simulation condition.

[0108] Evaluation module 300 is used to perform drop simulation of power batteries using the drop simulation mesh model, material properties, contact connection relationship, boundary and load of the power battery to obtain simulation data, and evaluate the strength performance and safety performance of the power battery under drop conditions based on the simulation data.

[0109] Optionally, in one embodiment of this application, the preset construction rules include: the drop simulation mesh model includes at least a main structure mesh model and a rigid surface; there is no interference between all mesh models in the drop simulation mesh model; the size of the rigid surface is larger than the size of the power battery, and the distance between the power battery frame and the edge of the rigid surface is greater than a preset threshold; the rigid surface is set parallel to the bottom protection plate of the power battery, and the gap between the rigid surface and the lowest point of the bottom of the power battery is within a preset range; a solid weld mesh model is established at each welded connection of the lower housing assembly of the power battery.

[0110] Optionally, in one embodiment of this application, the preset construction rules include: the extracted mid-surface of the plate structure of the power battery is divided into shell units, and the main mesh type of the plate structure is quadrilateral; the box welding assembly and cell module of the power battery are divided into hexahedral meshes.

[0111] Optionally, in one embodiment of this application, the setting module 200 includes: a first determining unit and a second determining unit.

[0112] The first determining unit is used to determine the density, elastic modulus, and Poisson's ratio of the material properties of all components.

[0113] The second determining unit is used to determine the material plasticity of the lower casing, bottom protective plate, liquid cooling plate, and cell casing of all components.

[0114] Optionally, in one embodiment of this application, the setting module 200 includes: a third determining unit, a first calculating unit, and a setting unit.

[0115] The third determining unit is used to determine the final drop velocity of the power battery based on the initial drop velocity and the drop height, in order to define the initial step.

[0116] The first calculation unit is used to calculate the time step of the drop simulation of the power battery based on the final drop velocity, so as to define the load step.

[0117] The setting unit is used to set the boundaries and loads based on the initial step and the load step.

[0118] Optionally, in one embodiment of this application, the evaluation module 300 includes: a fourth determining unit, a second calculation unit, and a fifth determining unit.

[0119] The fourth determining unit is used to determine the structural stress of the lower housing assembly of the power battery based on simulation data.

[0120] The second calculation unit is used to calculate the deformation of the power battery.

[0121] The fifth determining unit is used to determine the strength and safety performance based on the structural stress and deformation of the lower housing assembly.

[0122] Optionally, in one embodiment of this application, It should be noted that the foregoing explanation of the embodiment of the drop evaluation method for power batteries also applies to the drop evaluation device for power batteries in this embodiment, and will not be repeated here.

[0123] The drop evaluation device for power batteries proposed in this application can establish a non-interference, finely detailed drop simulation mesh model of the power battery according to construction rules. It accurately assigns material properties to all components and sets contact connections, boundaries, and loads that conform to physical reality, thereby simulating the drop conditions of the power battery. This allows for the analysis and evaluation of the strength and safety performance of the power battery under drop conditions, guiding and optimizing the structural design of the power battery, improving its strength and safety performance, and effectively increasing R&D efficiency and reducing R&D costs. This solves the problems in related technologies where insufficient structural coverage and detail in the simulation model leads to calculation errors due to the failure to consider the stress deformation and contact of internal structural components of the power battery, and the lack of a finite element simulation analysis and evaluation system for power battery drop tests, making it difficult to meet the strength and safety performance evaluation requirements of power batteries under drop conditions.

[0124] Figure 7 A schematic diagram of the structure of a vehicle provided in an embodiment of this application. The vehicle may include: The memory 701, the processor 702, and the computer program stored on the memory 701 and executable on the processor 702.

[0125] When the processor 702 executes the program, it implements the drop evaluation method for the power battery provided in the above embodiments.

[0126] Furthermore, the vehicle also includes: Communication interface 703 is used for communication between memory 701 and processor 702.

[0127] The memory 701 is used to store computer programs that can run on the processor 702.

[0128] The memory 701 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0129] If the memory 701, processor 702, and communication interface 703 are implemented independently, then the communication interface 703, memory 701, and processor 702 can be interconnected via a bus to complete communication between them. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized into address buses, data buses, control buses, etc. For ease of representation, Figure 7 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0130] Optionally, in a specific implementation, if the memory 701, processor 702, and communication interface 703 are integrated on a single chip, then the memory 701, processor 702, and communication interface 703 can communicate with each other through an internal interface.

[0131] The processor 702 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application.

[0132] This application also provides a non-volatile computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the above-described method for evaluating the drop performance of a power battery.

[0133] This application also provides a computer program product storing a computer program that, when executed by a processor, implements the above-described method for evaluating the drop performance of a power battery.

[0134] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0135] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0136] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0137] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0138] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. If implemented in hardware, as in another embodiment, it can be implemented using any one or more of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0139] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0140] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0141] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A method for evaluating the drop performance of a power battery, characterized in that, Includes the following steps: A drop simulation mesh model of the power battery is constructed based on preset construction rules to determine the material properties of all components in the power battery. Determine the contact connection relationship of the power battery drop simulation condition, and set the boundary and load of the power battery drop simulation condition; The power battery drop simulation mesh model, material properties, contact connection relationship, boundary and load are used to simulate the drop of the power battery to obtain simulation data, and the strength performance and safety performance of the power battery under drop conditions are evaluated based on the simulation data.

2. The method according to claim 1, characterized in that, The preset construction rules include: The drop simulation mesh model includes at least a main structural mesh model and a rigid surface; There is no interference between all mesh models in the drop simulation mesh model; The size of the rigid surface is larger than the size of the power battery, and the distance between the edge of the power battery and the edge of the rigid surface is greater than a preset threshold. The rigid surface is arranged parallel to the bottom protective plate of the power battery, and the gap between it and the lowest point of the bottom of the power battery is within a preset range. A solid weld mesh model is established at each welded joint of the lower housing assembly of the power battery.

3. The method according to claim 1 or 2, characterized in that, The preset construction rules include: The plate-like structure of the power battery is divided into shell units on the extracted surface, and the main grid type of the plate-like structure is quadrilateral. The battery pack housing assembly and the cell module are divided into a hexahedral mesh.

4. The method according to claim 1, characterized in that, Determining the material properties of all components in the power battery includes: Determine the density, elastic modulus, and Poisson's ratio of the material properties of all components; Determine the material plasticity of the lower housing, bottom protective plate, liquid cooling plate, and cell housing of all the aforementioned components.

5. The method according to claim 1, characterized in that, The setting of the boundaries and loads for the power battery drop simulation condition includes: The final drop velocity of the power battery is determined based on the initial drop velocity and the drop height to define the initial step; The time step of the drop simulation condition of the power battery is calculated based on the final drop velocity to define the load step; The boundary and the load are set according to the initial step and the load step.

6. The method according to claim 1, characterized in that, The evaluation of the strength and safety performance of the power battery under drop conditions based on the simulation data includes: Based on the simulation data, the structural stress of the lower housing assembly of the power battery is determined; Calculate the deformation of the power battery; The strength performance and the safety performance are determined based on the structural stress of the lower housing assembly and the amount of deformation.

7. A drop evaluation device for a power battery, characterized in that, include: The determination module is used to construct a drop simulation mesh model of the power battery based on preset construction rules and determine the material properties of all components in the power battery. The setting module is used to determine the contact connection relationship of the power battery drop simulation condition, and to set the boundary and load of the power battery drop simulation condition. The evaluation module is used to perform drop simulation of the power battery using the drop simulation mesh model, material properties, contact connection relationship, boundary and load, so as to obtain simulation data, and evaluate the strength performance and safety performance of the power battery under drop conditions based on the simulation data.

8. A vehicle, characterized in that, include: A memory, a processor, and a computer program stored in the memory and capable of running on the processor, the processor executing the program to implement the drop evaluation method for a power battery as described in any one of claims 1-6.

9. A non-volatile computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the drop evaluation method for power batteries as described in any one of claims 1-6.

10. A computer program product, comprising a computer program, characterized in that, The computer program is executed to implement the drop evaluation method for power batteries as described in any one of claims 1-6.

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