Storage battery post-impact simulation analysis method based on assembly process

Abstract

The invention discloses a storage battery rear collision simulation analysis method based on an assembly process. The method comprises the following steps: presetting an initial friction coefficient of surface-to-surface contact of each component in a storage battery assembly finite element model; simulation is carried out by adjusting the peak value of the acceleration curve applied to the finite element model of the storage battery assembly, and a simulation critical acceleration curve when the storage battery body is thrown out is obtained; an actual sliding table test is carried out on the storage battery assembly, the peak value of an acceleration curve applied to the storage battery assembly is adjusted with the simulation critical acceleration curve as the reference, and a test critical acceleration curve that the storage battery body is thrown out is obtained; simulating the finite element model of the storage battery assembly by taking the test critical acceleration curve as input, and correcting the initial friction coefficient to obtain a standard finite element model; and integrating the standard finite element model into the whole vehicle collision model, and performing rear collision simulation analysis by using the integrated whole vehicle collision model. The problem that the storage battery fixing reliability prediction is inaccurate due to unreliable preset parameters during model establishment is solved.

Description

Technical Field

[0001] This application relates to the field of vehicle testing technology, specifically to a battery rear-impact simulation analysis method based on assembly process. Background Technology

[0002] With increasingly stringent automotive safety regulations, it is clearly stipulated that the battery must remain in its installed position and the cables must remain connected during and after crash tests. Because the battery mounting point may experience impact accelerations of up to tens of grams during a collision, and given the battery's significant mass, the reliability of its secure mounting directly affects whether the vehicle's crash safety performance meets the standards.

[0003] In the process of vehicle product development, simulation analysis is a key means to predict and optimize vehicle collision safety performance. It can identify design risks before the physical prototype is manufactured, effectively reducing development costs and time. However, traditional methods for analyzing the safety of batteries in rear-end collisions have the following drawbacks: (1) The simplified model ignores the actual mechanical behavior of contact, friction and separation between the battery body and the frame and pressure strip. Its modeling process relies heavily on the engineer's empirical assumptions, especially the setting of key parameters such as the friction coefficient of the contact surface lacks reliable basis, and often adopts the recommended values ​​or rough estimates from the material handbook. Such pre-set parameters have significant deviations from the mechanical response of the battery assembly under real impact loads, so that the model cannot accurately simulate the complex interaction between the two from the root. (2) The simulation results often deviate from the results of subsequent physical collision tests. That is, the simulation analysis suggests that the design is feasible, but the battery fails to fly out in the actual test. This inaccuracy of prediction makes it impossible for simulation to provide effective decision support in the design stage, losing its core value of early warning of risks. In the end, the problem can only be solved by manufacturing expensive physical prototypes and iterating repeatedly through "experiment-failure-improvement-re-experiment", which greatly increases the development cost and time. Summary of the Invention

[0004] This application provides a battery rear-collision simulation analysis method based on assembly process, which solves the technical problem that the existing rear-collision simulation model has unreliable preset key parameters, resulting in inaccurate prediction of the battery's fixed reliability in the vehicle rear-collision.

[0005] This application provides a battery rear-impact simulation analysis method based on assembly process, which includes: The initial friction coefficients of each component in the finite element model of the battery assembly are preset; the peak value of the acceleration curve applied to the finite element model of the battery assembly is adjusted to obtain the simulated critical acceleration curve of the battery body being thrown out. Actual slide test was conducted on the battery assembly. Based on the simulated critical acceleration curve, the peak value of the acceleration curve applied to the battery assembly was adjusted to obtain the test critical acceleration curve of the battery body being thrown out. Using the experimental critical acceleration curve as input, the finite element model of the battery assembly is simulated, the initial friction coefficient is corrected, and a standard finite element model is obtained. The standard finite element model is then integrated into the vehicle collision model, and the integrated vehicle collision model is used for rear-end collision simulation analysis.

[0006] In one implementation, the battery assembly finite element model is simulated using the experimental critical acceleration curve as input, and the initial friction coefficient is corrected to obtain a standard finite element model, which includes the following steps: If the battery body is not thrown out, the initial friction coefficient is gradually reduced according to the first preset gradient value to obtain multiple sets of test friction coefficients, and simulations are performed sequentially until the battery body is thrown out in the simulation. The test friction coefficient corresponding to the current simulation is used as the standard friction coefficient of the battery assembly finite element model to obtain the standard finite element model. If the battery body is thrown out, the initial friction coefficient is gradually increased according to the first preset gradient value to obtain multiple sets of experimental friction coefficients, and simulations are performed sequentially until the battery body is not thrown out in the simulation. The experimental friction coefficient corresponding to the current simulation is used as the standard friction coefficient of the battery assembly finite element model to obtain the standard finite element model.

[0007] In one embodiment, obtaining the simulated critical acceleration curve of the battery body being thrown out includes the following steps: An acceleration with a peak value that varies with the curve is applied to the finite element model of the battery assembly for simulation, and the battery body is judged by animation based on the simulation results. If the battery body is not thrown out, the peak value of the acceleration curve is increased by the second preset gradient value, and the simulation is performed in sequence until the battery body is thrown out. The acceleration curve corresponding to the current peak value is obtained as the simulation critical acceleration curve. If the battery body is thrown out, the peak value of the acceleration curve is reduced according to the second preset gradient value, and the simulation is performed sequentially until the battery body is no longer thrown out. The acceleration curve corresponding to the current peak value is obtained as the simulation critical acceleration curve.

[0008] In one implementation, obtaining the test critical acceleration curve includes the following steps: Using the simulated critical acceleration curve as the acceleration change input for the battery assembly, observe whether the battery body is thrown out. If the battery body is not thrown out, the peak value of the simulated critical acceleration curve is increased by the third preset gradient value, and the test is carried out in sequence until the battery body is thrown out during the test. The acceleration curve corresponding to the current peak value is taken as the test critical acceleration curve. If the battery body is thrown out, the peak value of the simulated critical acceleration curve is reduced by the third preset gradient value, and the test is carried out in sequence until the battery body is not thrown out during the test. The acceleration curve corresponding to the current peak value is taken as the test critical acceleration curve.

[0009] In one implementation, before obtaining the finite element model of the battery assembly, model preparation is also included, which comprises the following steps: Import the geometric model of the battery assembly, which includes the battery body, battery frame, left pressure bar, right pressure bar, and multiple bolts; The battery body is meshed using solid units, and the meshing at its pressure plate retains the concave rib geometric features; After extracting the mid-surface of the battery frame, left pressure strip and right pressure strip, shell elements are used for mesh generation, and the convex rib geometric features are retained in the mesh generation of the left pressure strip and right pressure strip; The battery frame is connected to the left pressure strip using a rigid unit.

[0010] In one embodiment, when establishing the finite element model of the battery assembly, the material constitutive model of the battery frame, the left pressure bar and the right pressure bar is the MAT24 model, and the material constitutive model of the battery body is the MAT1 model. By adjusting the density parameters of the MAT1 model, the weight of the finite element model of the battery body is made consistent with the actual weight.

[0011] In one embodiment, the surface-to-surface contact of the components includes: The bottom surface of the battery body and the supporting surface of the battery frame are in first-surface contact. The left pressure strip makes contact with the second surface between itself and the left pressure strip platform of the battery body; The right-side pressure strip makes contact with the third surface between the right-side pressure strip platform and the battery body.

[0012] In one implementation, when establishing the finite element model of the battery assembly, the right-side pressure strip is connected to the battery frame through a first bolt and a second bolt simulated by a beam element, and a preload is applied to the beam element using keywords.

[0013] In one implementation, the acceleration load is applied in the simulation to obtain the simulated critical acceleration curve by means of the following method: Create a tooling slide model and assign it material properties; The finite element model of the battery assembly is rigidly connected to the tooling slide model through the mounting points on its battery frame using the third, fourth, fifth, and sixth bolts; the acceleration curve is applied to the tooling slide model.

[0014] In one implementation, a standard finite element model is integrated into a vehicle collision model, and a rear-end collision simulation analysis is performed using the integrated vehicle collision model. This includes the following steps: Establish finite element models of each subsystem of the vehicle; assemble the standard finite element model into the vehicle crash model; Set the boundary conditions for the rear-end collision simulation analysis of the whole vehicle, including tire contact with the ground, contact between the rear collision trolley and the whole vehicle, contact of the whole vehicle itself, and the initial speed of the rear collision trolley. A rear-end collision simulation analysis of the entire vehicle is conducted to determine whether the battery body is at risk of being ejected in a real-world rear-end collision by analyzing the relative motion between the battery body and the battery frame.

[0015] The beneficial effects of the technical solutions provided in this application include: This paper proposes a battery rear-impact simulation analysis method based on assembly process. Traditional methods simplify modeling, while this application uses a surface-to-surface contact model based on the actual assembly process, providing a physical basis for simulating the relative sliding between the battery and the frame. Secondly, using an initial finite element model, by adjusting the peak acceleration of the simulated battery motion, the critical acceleration predicted by the model for battery ejection is quickly identified. Although the results based on initial parameters may be inaccurate, they provide a scientific and quantitative initial input for finding the actual critical acceleration of battery ejection in subsequent physical experiments, greatly avoiding the blindness of experiments and saving debugging time and costs. After obtaining the actual critical acceleration of battery ejection, the actual critical acceleration is used as the input to the initial finite element model for simulation. The uncertain key parameter preset in the model, namely the friction coefficient, is adjusted in reverse, ensuring that the simulated battery ejection in the initial finite element model is completely consistent with the physical experimental phenomenon. Thus, a model that was originally distorted due to unreliable preset parameters was calibrated into a high-fidelity, experimentally verified standard finite element model. Finally, the calibrated, high-reliability subsystem model was applied to vehicle-level simulation, ultimately achieving accurate and reliable prediction of the risk of battery ejection in a rear-end collision. Through experimental calibration, the simulation model can realistically reflect the mechanical behavior of the battery assembly under impact, making the simulation results highly consistent with physical experimental phenomena. This leads to more accurate and reliable assessments of design risks, enabling precise identification of fixed battery design risks early in the design phase, reducing the number of tests, and even potentially achieving a first-pass yield, thereby saving significant prototype manufacturing and testing costs and shortening the product development cycle. Attached Figure Description

[0016] Figure 1 A schematic flowchart of a battery rear-collision simulation analysis method based on assembly process provided in this application embodiment; Figure 2 This is a schematic diagram of the battery assembly from a first perspective provided in an embodiment of this application; Figure 3 This is a schematic diagram of the battery assembly from a second perspective, provided in an embodiment of this application. Figure 4 This is a schematic diagram of the structure of the battery body from a first perspective, provided in an embodiment of this application. Figure 5 This is a schematic diagram of the battery body from a second perspective, provided in an embodiment of this application. Figure 6 This is a schematic diagram of the battery frame structure provided in an embodiment of this application; Figure 7 This is a schematic diagram of the relevant structure of the battery assembly and tooling slide provided in the embodiments of this application; Figure 8 A schematic diagram of an acceleration curve with a peak value provided for an embodiment of this application; Figure 9 A schematic diagram of the process for obtaining the simulated critical acceleration curve provided in an embodiment of this application; Figure 10 A schematic diagram of the process for obtaining the experimental critical acceleration curve provided in an embodiment of this application; Figure 11 A schematic diagram illustrating the process of obtaining a standard finite element model provided in this application embodiment; Figure 12 This is a schematic diagram illustrating the process of performing rear-end collision simulation analysis of a vehicle using a standard finite element model, as provided in an embodiment of this application.

[0017] In the diagram: 1. Battery body; 101. Left pressure strip platform; 102. Right pressure strip platform; 103. Recessed rib; 2. Battery frame; 201. First bolt; 202. Second bolt; 203. Third bolt; 204. Fourth bolt; 205. Fifth bolt; 206. Sixth bolt; 3. Left pressure strip; 4. Right pressure strip; 5. Raised rib; 6. Tooling slide. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0019] To make the technical problem that this application aims to solve clearer, the causes of the technical problem will be analyzed in detail below: Existing technologies use rigid connections or bonded contacts to simplify the modeling of battery assemblies, but this approach has physical flaws. It ignores the complex mechanical behavior of relative sliding and separation that may occur between the battery body 1 and the battery frame 2 under actual operating conditions. Essentially, this simplification replaces the real physical process—which may result in the battery remaining stationary or sliding under friction—with an absolutely fixed assumption. Therefore, no matter how detailed the subsequent simulations are, the model's foundation is distorted, making it impossible to simulate the core failure mode of battery ejection. Secondly, in limited attempts to use contact modeling, the most critical and uncertain parameters in the model, including the coefficient of friction between the contact surfaces, lack scientific basis. Current practices typically rely on theoretical values ​​from material handbooks or engineers' personal experience for pre-setting. However, the coefficient of friction is influenced by various factors such as surface roughness, lubrication conditions, and assembly clamping force, making it a highly uncertain parameter. Relying on such uncertain pre-set parameters for the accuracy of simulation results leads to inherent unreliability in simulation predictions. In existing technologies, simulation and physical testing are two relatively isolated processes. When simulation results deviate from experimental results, there is a lack of an effective and systematic method to feed back the real physical phenomena reflected in the experiment into the simulation model and calibrate it. The common practice is to directly modify the product design rather than correcting the simulation model itself. This results in the simulation model remaining in a pre-set, inaccurate state, unable to become accurate through iterative learning, and thus failing to provide reliable guidance in subsequent development.

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0021] It is important to know that the CAD model of the battery assembly includes: battery body 1, battery frame 2, left pressure strip 3, right pressure strip 4, first bolt 201, second bolt 202, third bolt 203, fourth bolt 204, fifth bolt 205, and sixth bolt 206. The left pressure strip 3 is welded to the battery frame body 1, forming an assembly with the battery frame 2. The right pressure strip 4 is connected to the battery frame 2 via the first bolt 201 and the second bolt 202. The battery body 1 has pressure strip platforms on both sides, namely the left pressure strip platform 101 and the right pressure strip platform 102, both featuring concave ribs 103. The left pressure strip 3 and the right pressure strip 4 have protruding ribs 5.

[0022] The battery body 1 is placed on the support surface of the battery frame 2. The battery body 1 is pushed from right to left, so that the concave rib 103 of the left pressure strip 101 of the battery body 1 aligns with the convex rib 5 of the left pressure strip 3. Then, the right pressure strip 4 is installed and connected by bolts. During the tightening of the bolts, the right pressure strip 4 exerts a clamping force on the right pressure strip 102 of the battery body 1. Through the clamping force and the cooperation of the concave rib 103 and the convex rib 5, the battery body 1 cannot be thrown out of the battery frame before the critical impact load is reached.

[0023] This application provides a battery rear-impact simulation analysis method based on assembly process, referring to... Figure 1 , Figure 1 This is a schematic flowchart of a battery rear-impact simulation analysis method based on assembly process, provided in an embodiment of this application. Figure 1 As shown, the battery rear-impact simulation analysis method based on assembly process includes: S100. The initial friction coefficient of each component in the finite element model of the battery assembly is preset; the peak value of the acceleration curve applied to the finite element model of the battery assembly is adjusted to simulate and obtain the simulated critical acceleration curve of the battery body 1 being thrown out. S200. Conduct an actual slide test on the battery assembly. Using the simulated critical acceleration curve as a benchmark, adjust the peak value of the acceleration curve applied to the battery assembly to obtain the test critical acceleration curve of the battery body 1 being thrown out. S300: Using the experimental critical acceleration curve as input, simulate the finite element model of the battery assembly, correct the initial friction coefficient, and obtain the standard finite element model; integrate the standard finite element model into the vehicle collision model, and use the integrated vehicle collision model to perform rear-end collision simulation analysis.

[0024] This method simplifies modeling compared to traditional methods, while this application uses a surface-to-surface contact model based on real assembly processes, providing a physical basis for simulating the relative sliding between the battery body 1 and the battery frame 2. Secondly, by adjusting the peak acceleration of the simulated battery body 1 using the finite element model of the battery assembly, the critical acceleration predicted by the model for the battery body 1 to be thrown out is quickly identified. Although the results based on initial parameters may be inaccurate, they provide a scientific and quantitative initial input for finding the actual critical acceleration of the battery body 1 in subsequent physical experiments, greatly avoiding the blindness of the experiment and saving debugging time and costs. After obtaining the actual critical acceleration of the battery body 1, this critical acceleration is used as the input to the initial finite element model of the battery assembly for simulation. The pre-set uncertain key parameters in the model, namely the friction coefficient, are adjusted in reverse, ensuring that the simulated throwing out of the battery body 1 in the initial finite element model is completely consistent with the actual physical experiment phenomenon. Thus, a model that was originally distorted due to unreliable preset parameters was calibrated into a high-fidelity, experimentally verified standard finite element model. Finally, the calibrated, high-reliability subsystem model was applied to vehicle-level simulation, ultimately achieving accurate and reliable prediction of the risk of battery ejection in a rear-end collision. Through experimental calibration, the simulation model can realistically reflect the mechanical behavior of the battery assembly under impact, making the simulation results highly consistent with physical experimental phenomena. This leads to more accurate and reliable assessments of design risks, enabling precise identification of risks in the fixed design of the battery body 1 early in the design phase. It reduces the number of tests and may even allow for a single-test pass, thereby saving significant prototype manufacturing and testing costs and shortening the product development cycle.

[0025] Furthermore, in one embodiment, the battery assembly finite element model is simulated using the experimental critical acceleration curve as input, and the initial friction coefficient is corrected to obtain a standard finite element model, which includes the following steps: If the battery body 1 is not thrown out, the initial friction coefficient is gradually reduced according to the first preset gradient value to obtain multiple sets of test friction coefficients, and simulations are performed in sequence until the battery body 1 is thrown out in the simulation. The test friction coefficient corresponding to the current simulation is used as the standard friction coefficient of the battery assembly finite element model to obtain the standard finite element model. If the battery body 1 is thrown out, the initial friction coefficient is gradually increased according to the first preset gradient value to obtain multiple sets of experimental friction coefficients, and simulations are performed sequentially until the battery body 1 is not thrown out in the simulation. The experimental friction coefficient corresponding to the current simulation is used as the standard friction coefficient of the battery assembly finite element model to obtain the standard finite element model.

[0026] In this embodiment, if the simulated battery fails to eject but the experimental battery does, it indicates that the frictional force in the simulation model is overestimated, making the model more robust than in reality. In this case, the friction coefficient should be reduced. Conversely, if the simulated battery ejects but the experimental battery does not, it indicates that the frictional force in the simulation model is underestimated, making the model more loose than in reality. In this case, the friction coefficient should be increased. The iteration stops when the phenomenon of whether the battery body 1 is ejected in the simulation results is completely consistent with the phenomenon observed in the physical sliding test. At this point, the experimental friction coefficient used is the accurate and reliable standard friction coefficient calibrated from experimental data. Assigning this standard friction coefficient to the model yields the calibrated standard finite element model. This transforms the calibration process from relying on the engineer's personal experience to a repeatable scientific process based on a rigorous comparison of experimental phenomena and simulation results. By forcing the simulation model to converge to the standard of the physical test through an iterative algorithm, the objectivity and accuracy of the calibration results are ensured.

[0027] Furthermore, in one embodiment, obtaining the simulated critical acceleration curve of the battery body 1 as it is thrown out includes the following steps: An acceleration with a peak value that varies with the curve is applied to the finite element model of the battery assembly for simulation, and the battery body 1 is determined by animation based on the simulation results. If the battery body 1 is not thrown out, the peak value of the acceleration curve is increased by the second preset gradient value, and the simulation is performed in sequence until the battery body 1 is thrown out. The acceleration curve corresponding to the current peak value is obtained as the simulation critical acceleration curve. If the battery body 1 is thrown out, the peak value of the acceleration curve is reduced according to the second preset gradient value, and the simulation is performed sequentially until the battery body 1 is no longer thrown out. The acceleration curve corresponding to the current peak value is obtained as the simulation critical acceleration curve.

[0028] This embodiment addresses the challenge of providing a scientific and reasonable initial load input for subsequent physical slide table tests in the absence of real experimental data. This aims to fundamentally change the inefficient situation of blind debugging and repeated trial and error caused by inaccurate load estimation in traditional physical testing. The method leverages the rapid iterative advantages of computer simulation, completing numerous exploratory tests in a virtual space and using the found simulation critical points as the initial conditions for physical tests. This avoids the enormous time and cost of starting the test bench from scratch and blindly searching for load ranges, allowing physical tests to focus on the most critical load ranges from the outset. This significantly reduces the number of test debugging attempts and shortens the development cycle. By exploring extreme conditions in a virtual environment, potential risks can be exposed in advance, preventing unexpected situations such as specimen damage caused by excessively high initial test loads. This protects expensive test samples and reduces experimental risks and related costs.

[0029] Furthermore, in one embodiment, obtaining the experimental critical acceleration curve includes the following steps: Using the simulated critical acceleration curve as the acceleration change input for the battery assembly, observe whether the battery body 1 is thrown out. If the battery body 1 is not thrown out, the peak value of the simulated critical acceleration curve is increased by the third preset gradient value, and the test is carried out in sequence until the battery body 1 is thrown out during the test. The acceleration curve corresponding to the current peak value is taken as the test critical acceleration curve. If the battery body 1 is thrown out, the peak value of the simulated critical acceleration curve is reduced according to the third preset gradient value, and the test is carried out in sequence until the battery body 1 is not thrown out during the test. The acceleration curve corresponding to the current peak value is taken as the test critical acceleration curve.

[0030] In this embodiment, using the simulated critical acceleration curve as the input for the acceleration change of the battery assembly helps to quickly find the actual experimental critical acceleration curve, reducing the number of tests. Secondly, since using the simulated critical acceleration curve as the input for the acceleration change of the battery assembly may result in peak values ​​that are too high or too low, the battery body 1 may or may not be ejected under the input of the critical acceleration curve. Based on different situations, the peak value of the acceleration curve is adjusted differently until the experimental critical acceleration curve is obtained where the battery body 1 is just ejected or just not ejected. By using the simulation results as the initial input for the experiment, the search range of the experiment is changed from a wide-area blind search to a local refinement, significantly reducing the number of tests required. This not only saves high experimental costs and time but also reduces wear and tear on the experimental equipment.

[0031] Furthermore, in one embodiment, before obtaining the finite element model of the battery assembly, model preparation is also included, which includes the following steps: Import the geometric model of the battery assembly. The geometric model includes the battery body 1, battery frame 2, left pressure strip 3, right pressure strip 4, and multiple bolts. The battery body 1 is meshed using solid elements, and the geometric features of the concave rib 103 are retained in the meshing at its pressure plate. After extracting the mid-surface of the battery frame 2, the left pressure strip 3 and the right pressure strip 4, shell elements are used for meshing, and the geometric features of the rib 5 are retained in the meshing of the left pressure strip 3 and the right pressure strip 4; the battery frame 2 and the left pressure strip 3 are connected by rigid elements.

[0032] In this embodiment, the goal is to establish a finite element model that accurately reflects the actual assembly process characteristics of the battery assembly from a geometric perspective, particularly the fit between the concave ribs 103 and convex ribs 5, and the connection relationships between components. This overcomes the fundamental deficiency of traditional simplified models, which, due to the lack of geometric features, cannot simulate the actual mechanical behavior between the battery body 1 and the battery frame 2, such as sliding, engagement, and separation. By refining the mesh and retaining the key geometric features of the concave ribs 103 and convex ribs 5, the model possesses the physical basis to simulate real contact, friction, and even mechanical engagement effects. This is a prerequisite for reproducing the failure mode of ejection, changing the inherent distortion of traditional simplified models. Through accurate geometric import and simulation of connection relationships based on actual assembly processes, such as the rigid connection of welded parts, the finite element model is ensured to be as close as possible to the actual connection relationships in terms of geometry and connection relationships, reducing simulation errors caused by model deviations.

[0033] Furthermore, in one embodiment, when establishing the finite element model of the battery assembly, the material constitutive model of the battery frame 2, the left pressure strip 3 and the right pressure strip 4 is the MAT24 model, and the material constitutive model of the battery body 1 is the MAT1 model. By adjusting the density parameters of the MAT1 model, the weight of the finite element model of the battery body 1 is made consistent with the actual weight.

[0034] In this embodiment, the battery frame 2, left pressure strip 3, and right pressure strip 4 are typically made of metal and undergo plastic deformation during a collision. Therefore, their material constitutive model is preferably the MAT24 model, which can accurately simulate the complete mechanical behavior of metal materials from the elastic stage to plastic yielding and failure. The required material parameters include: density, elastic modulus, Poisson's ratio, and most importantly, the true stress-strain curve. This curve is obtained through standard material testing to ensure its accuracy. The main function of the battery body 1 is to provide mass (inertial effect), and structural deformation during a collision is not the focus of the analysis. Therefore, its material constitutive model is preferably the MAT1 linear elastic model. The elastic modulus and Poisson's ratio need to be input, the core meaning of which is to define a deformable body with reasonable stiffness to correctly simulate its contact interaction with surrounding components; since the MAT1 model only defines stiffness by default, its mass is automatically calculated from the mesh volume and density. To ensure the accuracy of inertial forces in the simulation, model weight calibration is necessary. This is achieved by adjusting the density parameters in the MAT1 model assigned to battery body 1, ensuring that the calculated weight of the finite element model of this component is strictly consistent with the actual weighed weight of the battery. This guarantees the accuracy of subsequent dynamic simulation results.

[0035] Furthermore, in one embodiment, the surface-to-surface contact of the components includes: The bottom surface of the battery body 1 and the supporting surface of the battery frame 2 are in first-surface contact. The left pressure strip 3 and the left pressure strip platform 101 of the battery body 1 are in second-surface contact; The right-side pressure strip 4 and the right-side pressure strip platform 102 of the battery body 1 are in third-side surface contact.

[0036] In this embodiment, after completing geometric modeling and material definition, accurately defining the contact relationships between components is the core step in simulating the real mechanical behavior of the battery assembly. This embodiment specifically defines the key surface-to-surface contact pairs necessary to achieve the simulation objectives, ensuring the model can accurately simulate the interaction between the battery body 1 and the fixed structure under impact loads. The first surface-to-surface contact simulates the battery weight and its friction and possible relative sliding with the supporting foundation under impact inertial force; the second surface-to-surface contact simulates the key effects of the left-side fixed constraint and the interaction between the concave rib 103 and the convex rib 5; and the third surface-to-surface contact simulates the clamping effect of the right-side pressure strip 4. By accurately setting these three key surface-to-surface contacts, the model possesses the ability to simulate complex mechanical behaviors such as friction and sliding between the battery body 1 and the bottom surface of the battery frame 2 under inertial force, and compression and separation from the left and right pressure strips 3 and 4. This is a necessary and sufficient condition for successfully reproducing the ejection failure mode, making the simulation analysis more accurate.

[0037] Furthermore, in one embodiment, when establishing the finite element model of the battery assembly, the right pressure strip 4 is connected to the battery frame 2 through the first bolt 201 and the second bolt 202 simulated by the beam element, and the preload is applied to the beam element using keywords.

[0038] In this embodiment, accurate modeling of the mechanical behavior of key connecting components is crucial for precisely simulating the actual assembly state of the battery assembly. This embodiment specifically illustrates how to simulate the bolt connection of the right-side pressure strip 4 and its generated preload in a finite element model; the right-side pressure strip 4 is connected to the battery frame 2 via a first bolt 201 and a second bolt 202. In the finite element model, beam elements are used to simulate the bolt shank. The two end nodes of this beam element are connected to the surrounding areas of the bolt holes on the right-side pressure strip 4 and the corresponding threaded holes on the battery frame 2 via rigid elements, respectively, to simulate the tightening effect of the bolt. To accurately simulate the clamping effect of the bolt on the right-side pressure strip 4 after tightening, a preload needs to be applied to the beam element simulating the bolt. This operation is achieved by calling a keyword instruction, and the magnitude of the preload needs to be set. This force value should be calculated based on the torque requirements of the actual assembly process. The direction of the preload is set to make the beam element tensile, thereby simulating the clamping force generated on the connecting parts after the bolt is tightened.

[0039] Furthermore, in one embodiment, in the simulation to obtain the simulated critical acceleration curve, the acceleration load is applied in the following manner: Create a tooling slide 6 model and assign it material properties; The finite element model of the battery assembly is rigidly connected to the tooling slide 6 model through the mounting points on its battery frame 2 using the third bolt 203, the fourth bolt 204, the fifth bolt 205 and the sixth bolt 206; the acceleration curve is applied to the tooling slide 6 model.

[0040] In this embodiment, a tooling slide model 6 with a geometry matching the physical test bench is created. The dimensions of this slide model should ensure that it can provide a stable mounting base for the battery assembly. The tooling slide model 6 is given rigid material properties; it is defined as a rigid body that will not deform during simulation, ensuring that the input acceleration energy is fully used to drive the entire system's motion and is not consumed by its own deformation. The finite element model of the battery assembly is positioned on the tooling slide model 6 according to the actual vehicle assembly state, simulating the tight connection between the battery assembly and the test bench. The mounting points on the battery frame 2, corresponding to the mounting positions of the third bolt 203, fourth bolt 204, fifth bolt 205, and sixth bolt 206, are rigidly connected to the corresponding positions on the upper surface of the tooling slide model 6 using rigid elements. This connection method simulates the situation in physical experiments where rigid clamps are used to firmly fix the specimen to the slide table surface, ensuring that the load can be transferred without loss. The acceleration-time curve used to simulate the impact is applied directly to the reference point of the tooling slide table 6 model as a boundary condition. This is equivalent to driving the slide table surface to move in a physical experiment, thereby causing the battery assembly on it to undergo the acceleration and deceleration impact process.

[0041] Furthermore, in one embodiment, a standard finite element model is integrated into a vehicle collision model, and a rear-end collision simulation analysis is performed using the integrated vehicle collision model. This includes the following steps: Establish finite element models of each subsystem of the vehicle; assemble the standard finite element model into the vehicle crash model; Set the boundary conditions for the rear-end collision simulation analysis of the whole vehicle, including tire contact with the ground, contact between the rear collision trolley and the whole vehicle, contact of the whole vehicle itself, and the initial speed of the rear collision trolley. A rear-end collision simulation analysis of the entire vehicle is conducted. By analyzing the relative motion state between the battery body 1 and the battery frame 2, it is determined whether the battery body 1 is at risk of being ejected during a real-world rear-end collision.

[0042] In this embodiment, a complete vehicle collision finite element model is established or invoked, including the body-in-white, opening and closing components (doors, hood, trunk lid), interior and exterior trim, powertrain, front and rear suspension systems, tires, and rear axle system. Each subsystem must have completed material assignment, mesh generation, and internal connections. The standard finite element model obtained above and calibrated through slide test is integrated into the vehicle collision model according to its precise assembly position and orientation in the actual vehicle's engine compartment. All necessary mechanical connections are established to ensure the correct transmission of force and motion; the contact relationship between the tires and the ground is defined to simulate the vehicle's grounding state during a collision; the contact between the rear collision trolley and the front bumper, rear longitudinal beams, and other rear structures of the vehicle is defined; all self-contacts between and within each subsystem are defined to prevent penetration and non-physical behavior. An initial velocity is assigned to the rear collision trolley to simulate a rear-end collision; the vehicle model is submitted for explicit dynamics calculation. After the calculation is completed, the simulation result animation is analyzed in detail. Observe and evaluate the relative motion state between the battery body 1 and the battery frame 2, specifically including: whether there is obvious relative displacement or slippage, whether the displacement exceeds the design safety clearance, and whether the failure mode of the battery body 1 completely detaching from the battery frame 2 has occurred. Based on the analysis results, determine whether the battery assembly is at risk of being ejected in a rear-end collision of a real vehicle under the current design, and provide a direct and reliable basis for design optimization.

[0043] The beneficial effects of this invention include: (1) By establishing a refined finite element model, namely retaining assembly features such as concave rib 103 and convex rib 5, defining contact relationships, simulating bolt preload, and using physical slide test data to accurately calibrate key parameters that are uncertain in the model, such as the friction coefficient, the problem of distortion caused by simplification in traditional simulation models is solved. This enables the simulation results to truly reflect the motion state of the battery under impact load, and to achieve reliable prediction of the risk of battery ejection.

[0044] (2) This method reduces the blindness and repetition of physical experiments by using a process of simulation first, experimental verification, and then feedback calibration. The calibrated high-precision model can be used for reliable virtual verification, thereby reducing the reliance on expensive physical prototype vehicle crash tests, saving a lot of development costs and time, and improving development efficiency.

[0045] (3) This solution integrates modeling, test calibration and vehicle application based on assembly process into a complete and standardized analysis method. This process is easy to promote and reuse in different projects and teams, transforming personal experience into standardized core analysis capabilities for enterprises, and improving the reliability of the overall R&D level.

[0046] It should be noted that the sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0047] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0048] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0049] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0050] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0051] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.

[0052] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A battery rear-impact simulation analysis method based on assembly process, characterized in that, It includes: The initial friction coefficients of the surface-to-surface contact of each component in the finite element model of the battery assembly are preset; The simulation critical acceleration curve of the battery body (1) being thrown out was obtained by adjusting the peak value of the acceleration curve applied to the finite element model of the battery assembly. An actual slide test was conducted on the battery assembly. Based on the simulated critical acceleration curve, the peak value of the acceleration curve applied to the battery assembly was adjusted to obtain the test critical acceleration curve of the battery body (1) being thrown out. Using the experimental critical acceleration curve as input, the finite element model of the battery assembly is simulated, the initial friction coefficient is corrected, and a standard finite element model is obtained; the standard finite element model is integrated into the vehicle collision model, and the integrated vehicle collision model is used to perform rear-end collision simulation analysis.

2. The battery rear-impact simulation analysis method based on assembly process as described in claim 1, characterized in that, Using the experimental critical acceleration curve as input, the finite element model of the battery assembly is simulated, and the initial friction coefficient is corrected to obtain a standard finite element model, which includes the following steps: If the battery body (1) is not thrown out, the initial friction coefficient is gradually reduced according to the first preset gradient value to obtain multiple sets of test friction coefficients, and simulations are performed in sequence until the battery body (1) is thrown out in the simulation. The test friction coefficient corresponding to the current simulation is used as the standard friction coefficient of the battery assembly finite element model to obtain the standard finite element model. If the battery body (1) is thrown out, the initial friction coefficient is gradually increased according to the first preset gradient value to obtain multiple sets of test friction coefficients, and simulations are performed in sequence until the battery body (1) is not thrown out in the simulation. The test friction coefficient corresponding to the current simulation is used as the standard friction coefficient of the battery assembly finite element model to obtain the standard finite element model.

3. The battery rear-impact simulation analysis method based on assembly process as described in claim 1, characterized in that, Obtain the simulated critical acceleration curve of the battery body (1) after it is thrown out, which includes the following steps: An acceleration with a peak value that varies with the curve is applied to the finite element model of the battery assembly for simulation, and the battery body (1) is determined by animation based on the simulation results; If the battery body (1) is not thrown out, the peak value of the acceleration curve is increased by the second preset gradient value, and the simulation is performed in sequence until the battery body (1) is thrown out. The acceleration curve corresponding to the current peak value is obtained as the simulation critical acceleration curve. If the battery body (1) is thrown out, the peak value of the acceleration curve is reduced according to the second preset gradient value, and the simulation is performed sequentially until the battery body (1) is no longer thrown out. The acceleration curve corresponding to the current peak value is obtained as the simulation critical acceleration curve.

4. The battery rear-impact simulation analysis method based on assembly process as described in claim 1, characterized in that, Obtaining the critical acceleration curve for the experiment includes the following steps: Using the simulated critical acceleration curve as the acceleration change input of the battery assembly, observe whether the battery body (1) is thrown out; If the battery body (1) is not thrown out, the peak value of the simulated critical acceleration curve is increased by the third preset gradient value, and the test is carried out in sequence until the battery body (1) is thrown out during the test. The acceleration curve corresponding to the current peak value is taken as the test critical acceleration curve. If the battery body (1) is thrown out, the peak value of the simulated critical acceleration curve is reduced according to the third preset gradient value, and the test is carried out in sequence until the battery body (1) is not thrown out during the test. The acceleration curve corresponding to the current peak value is taken as the test critical acceleration curve.

5. The battery rear-impact simulation analysis method based on assembly process as described in claim 1, characterized in that, Before obtaining the finite element model of the battery assembly, model preparation is also included, which includes the following steps: Import the geometric model of the battery assembly, which includes the battery body (1), battery frame (2), left pressure strip (3), right pressure strip (4) and multiple bolts; The battery body (1) is meshed using solid units, and the geometric features of the concave rib (103) are retained in the meshing at its pressure plate. After extracting the mid-surface of the battery frame (2), left pressure strip (3) and right pressure strip (4), shell units are used for meshing, and the geometric features of the rib (5) are retained in the meshing of the left pressure strip (3) and right pressure strip (4); The battery frame (2) is connected to the left pressure strip (3) by a rigid unit.

6. The battery rear-impact simulation analysis method based on assembly process as described in claim 5, characterized in that, When establishing the finite element model of the battery assembly, the material constitutive model of the battery frame (2), the left pressure bar (3) and the right pressure bar (4) is the MAT24 model, and the material constitutive model of the battery body (1) is the MAT1 model. By adjusting the density parameters of the MAT1 model, the weight of the finite element model of the battery body (1) is made consistent with the actual weight.

7. The battery rear-impact simulation analysis method based on assembly process as described in claim 5, characterized in that, The surface-to-surface contact of each component includes: The bottom surface of the battery body (1) and the supporting surface of the battery frame (2) are in first-surface contact; The left pressure strip (3) is in contact with the second surface of the left pressure strip platform (101) of the battery body (1); The right side pressure strip (4) is in contact with the right side pressure strip platform (102) of the battery body (1) on the third surface.

8. The battery rear-impact simulation analysis method based on assembly process as described in claim 5, characterized in that, When establishing the finite element model of the battery assembly, the right pressure strip (4) is connected to the battery frame (2) through the first bolt (201) and the second bolt (202) simulated by the beam element, and the preload is applied to the beam element using keywords.

9. The battery rear-impact simulation analysis method based on assembly process as described in claim 5, characterized in that, In the simulation to obtain the simulated critical acceleration curve, the acceleration load is applied in the following manner: Create a tooling slide model (6) and assign it material properties; The finite element model of the battery assembly is rigidly connected to the tooling slide (6) model through the mounting point on its battery frame (2) using the third bolt (203), the fourth bolt (204), the fifth bolt (205) and the sixth bolt (206); the acceleration curve is applied to the tooling slide (6) model.

10. The battery rear-impact simulation analysis method based on assembly process as described in claim 5, characterized in that, The standard finite element model is integrated into the vehicle collision model, and a rear-end collision simulation analysis is performed using the integrated vehicle collision model. This includes the following steps: Establish finite element models of each subsystem of the vehicle; assemble the standard finite element models into the vehicle collision model; Set the boundary conditions for the rear-end collision simulation analysis of the whole vehicle, including tire contact with the ground, contact between the rear collision trolley and the whole vehicle, contact of the whole vehicle itself, and the initial speed of the rear collision trolley. A rear-end collision simulation analysis of the whole vehicle was conducted. By analyzing the relative motion state between the battery body (1) and the battery frame (2), it was determined whether the battery body (1) was at risk of being thrown out in a real vehicle rear-end collision.

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