CN116894369A - Power battery pack bottom collision simulation method, system and electronic equipment - Google Patents

Abstract

The invention discloses a power battery pack bottom collision simulation method, system and electronic equipment, and relates to the technical field of electrical digital data processing. The power battery pack bottom collision simulation method provided by the present invention constructs a battery pack model, a trolley model and an obstacle model, and establishes a ground model. Based on the battery pack model, the trolley model and the obstacle model, a simulation test model is formed, using simulation The test model conducts a collision simulation test on the bottom of the power battery pack according to the set working condition information. During the simulation test, the response of the battery pack during the collision can be understood in real time and the simulation analysis results can be obtained to solve the cost-intensive test method existing in the existing technology. It is large, and the test plan does not have corresponding regulations and standards, etc., thus providing new ideas for battery pack safety testing.

Description

A power battery pack bottom collision simulation method, system and electronic equipment

Technical field

The invention relates to the technical field of electrical digital data processing, and in particular to a power battery pack bottom collision simulation method, system and electronic equipment.

Background technique

With the rapid development of new energy, the demand for batteries in energy storage, automobiles and other fields is getting stronger and stronger. To meet the relevant R&D and testing needs, corresponding test systems need to be developed.

Since the dynamic safety of the bottom of the battery pack is a more prominent issue due to the rapid development of new energy vehicles in recent years, in terms of simulation and modeling of collisions at the bottom of the battery pack, the simplified model methods currently used by various companies are also different, or there is no Aware of analyzing the safety performance of battery packs during bottom collisions through simulation modeling methods. Common simulation analysis is currently used in collisions to build vehicle models and conduct safety evaluation and analysis in aspects such as European New Car Assessment Program (CNCAP) and pedestrian protection.

In terms of current dynamic safety testing at the bottom of the battery pack, performance testing is mainly conducted through the bottom test. However, this test method is costly and there are no corresponding regulatory standards for the test plan.

Contents of the invention

In order to solve the above-mentioned problems existing in the prior art, the present invention provides a power battery pack bottom collision simulation method, system and electronic equipment.

In order to achieve the above objects, the present invention provides the following solutions:

A collision simulation method for the bottom of a power battery pack, including:

Construct a battery pack model, a trolley model and an obstacle model; the battery pack model, the trolley model and the obstacle model are all three-dimensional models;

Establish a ground model, and form a simulation test model based on the battery pack model, the trolley model and the obstacle model;

The simulation test model is used to conduct a collision simulation test on the bottom of the power battery pack according to the set working condition information to obtain simulation analysis results.

Optionally, the method also includes:

Perform coupling of mass units on the battery pack model to obtain mass points;

Counterweighting is performed based on the mass points to simulate the mass of the vehicle to be tested.

Optionally, establish a ground model and form a simulation test model based on the battery pack model, the trolley model and the obstacle model, specifically including:

The finite element method is used to mesh the battery pack model, the trolley model and the obstacle model to obtain the battery pack finite element model, the trolley finite element model and the obstacle finite element model, and establish and trolley A ground model with the same lowest point height to form the simulation test model.

Optionally, use the simulation test model to conduct a collision simulation test on the bottom of the power battery pack according to the set working condition information to obtain simulation analysis results, which specifically include:

The variational method is used to solve the simulation test model to obtain the motion process of the trolley model with the battery pack when it hits an obstacle.

Optionally, before using the simulation test model to conduct the power battery pack bottom collision simulation test according to the set working condition information to obtain the simulation analysis results, it also includes:

Given the battery pack material model equation;

The stress-strain curve of the material selected during the manufacturing process of the battery pack object is determined based on the battery pack material model equation.

According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

The power battery pack bottom collision simulation method provided by the present invention constructs a battery pack model, a trolley model and an obstacle model, and establishes a ground model, and forms a simulation test based on the battery pack model, the trolley model and the obstacle model. Model, the simulation test model is used to conduct a collision simulation test on the bottom of the power battery pack according to the set working condition information. During the simulation test process, the response of the battery pack during the collision can be understood in real time and the simulation analysis results can be obtained to solve the problem of the existing technology. The existing test methods are expensive, and the test plans do not have corresponding regulations and standards, etc., thus providing new ideas for battery pack safety testing.

In addition, the present invention also provides the following implementation structure:

A power battery pack bottom collision simulation system, applied to the power battery pack bottom collision simulation method provided above; the system includes:

A three-dimensional model building module is used to build a battery pack model, a trolley model and an obstacle model; the battery pack model, the trolley model and the obstacle model are all three-dimensional models;

A simulation model generation module is used to establish a ground model and form a simulation test model based on the battery pack model, the trolley model and the obstacle model;

The simulation test module is used to use the simulation test model to conduct a collision simulation test on the bottom of the power battery pack according to the set working condition information to obtain simulation analysis results.

An electronic device including:

Memory, used to store computer programs;

A processor, connected to the memory, is used to retrieve and execute the computer program to implement the power battery pack bottom collision simulation method provided above.

Optionally, the memory is a computer-readable storage medium.

Since the technical effects achieved by the above two implementation structures provided by the present invention are the same as those achieved by the power battery pack bottom collision simulation method provided by the present invention, they will not be described again here.

Description of the drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the drawings needed to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some of the drawings of the present invention. Embodiments, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without exerting creative efforts.

Figure 1 is a flow chart of the power battery pack bottom collision simulation method provided by the present invention;

Figure 2 is a schematic diagram of the stress strain curve provided by the present invention;

Figure 3 is a schematic diagram of the battery pack model provided by the present invention;

Figure 4 is a schematic diagram of the battery pack model and obstacle model provided by the present invention;

Figure 5 is a schematic diagram of the battery pack model, trolley model, obstacle model and ground model provided by the present invention;

Figure 6 is a schematic diagram of a trolley model equipped with a battery pack model provided by the present invention;

Figure 7 is a front view of the ground model, trolley model and battery pack model provided by the present invention;

Figure 8 is a top view of the ground model, trolley model and battery pack model provided by the present invention;

Figure 9 is a schematic front view of the mass point provided by the present invention;

Figure 10 is a top view of the mass point provided by the present invention;

Figure 11 is a schematic diagram of the simulation results of the battery pack bottom collision provided by the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

The purpose of the present invention is to provide a power battery pack bottom collision simulation method, system and electronic equipment, which can understand the response of the battery pack during the collision process in real time, so as to solve the problem of high cost and high cost of the test method existing in the existing technology. The test plan also has no corresponding regulations and standards, thus providing new ideas for battery pack safety testing.

In order to make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

As shown in Figure 1, the power battery pack bottom collision simulation method provided by the present invention includes:

Step 100: Establish the battery pack model and obstacle model. In the actual application process, the established battery pack model and obstacle model are shown in Figures 3 and 4.

In this step, computer finite element analysis software is used to build the battery pack model and the obstacle model that collides with the battery pack. In the process of building the battery pack model, it is very important to couple the mass unit of the battery pack model, because if the mass size is not set, only the mass of the battery pack model and the trolley model will participate in the collision process, and this The working condition simulated by the inventive method is an electric vehicle equipped with a battery pack. Therefore, the quality of the battery pack model and the trolley model needs to be redefined, that is, a new mass point is coupled. The mass of the new mass point is: actual vehicle mass. By subtracting the mass of the battery pack model and the trolley model in the simulation model, the system model is weighted by coupling new mass points, so that the actual vehicle mass can be simulated. Among them, the mass point 3 obtained by coupling can also be called a mass coupling unit, as shown in Figures 9 and 10.

Based on this, in the actual application process, first use commonly used commercial software to establish a three-dimensional geometric model based on the actual size of the battery pack of the tested sample, such as length, width, component thickness, and geometric relationships between components for drawing. Among them, the three-dimensional geometric model of the battery pack is generally a design component that will be produced and put into the market later. Therefore, this data is an existing data model, that is, a three-dimensional electronic model of the component under test. It can also be used to scan existing batteries using a three-dimensional scanner. Scan the actual items and obtain a three-dimensional electronic model in IGS format.

Step 101: Establish a trolley model, and install and combine the trolley model and the battery pack model, as shown in Figures 5 and 6.

Specifically, computer finite element analysis software is used to build a trolley model that can load the battery pack model. Among them, the size of the trolley model is selected according to the size of the battery pack model. Generally, it is ensured that the front and rear wheelbase L of the trolley is greater than the maximum length of the battery pack, and the width of the trolley model is greater than or equal to the width of the battery pack model.

Step 102: Establish a ground model, that is, establish an infinite horizontal ground RIGIDWall tangent to the trolley hub, as shown in Figure 5 and Figures 7 and 8. Among them, the reference number 1 in Figure 5 represents an obstacle, and the reference number 2 in Figure 5 and Figures 7 and 8 represents a horizontal ground.

Among them, computer finite element analysis software is used to build a RIGDWALL model that simulates the earth's ground. The trolley carrying the battery pack can always remain above this plane during the collision with obstacles, avoiding the situation where the calculation simulation time is too long. The battery pack model appears to fly freely.

Step 103: Set the obstacle ball to be fixed and the battery pack to hit to the right.

Through computer finite element analysis software, the bottom collision simulation analysis working condition is designed: fixed constraints are set on the obstacle sphere (i.e., the obstacle model), and the battery pack is given a certain initial speed to hit the obstacle horizontally. This working condition is a model road The battery pack at the bottom of the electric vehicle may encounter certain obstacles and collision accidents during driving. Therefore, the safety test and analysis of the structure of the bottom of the battery pack can be carried out through this working condition.

Step 104: Implement a simulated battery pack bottom collision test.

Through computer finite element analysis software, after setting the analysis working conditions, the simulation test model can be put into the server for calculation, thereby obtaining the simulation analysis results under the working conditions. Among them, the input data of the server is under the simulation model, given the speed of the battery pack hitting the obstacle, which can be any value such as 5km/h, 10km/h..., the entire simulation model (or system) is completed. A key format file is created. The key format file contains the above model information. The key file can be input into commercial finite element calculation software (such as ls-dyna) for calculation. Through calculation, the dynamic process of the entire collision process and the battery can be obtained. Includes analysis parameters such as displacement, velocity, and acceleration of each node. By changing the input data, such as the collision speed V, the simulation test model can still be applied. The parameters of the simulation test model can be adjusted according to the actual situation, such as the mass parameters and speed parameters of the entire collision process.

In the actual application process, the present invention uses the finite element method to perform simulation. Among them, the finite element method is a numerical technique for solving approximate solutions to boundary value problems of partial differential equations. When solving, the entire model area is decomposed, and each sub-area becomes a simple part. Through the variation method, the error function reaches the minimum value. And generate stable solutions. The basic idea is to decompose the continuous solution area into a set of finite small interconnected units, assume a suitable approximate solution for each unit, and then deduce the overall satisfying conditions for solving this domain, thereby obtaining the solution to the problem. . Therefore, when conducting the numerical simulation analysis of the battery pack bottom collision, the above-mentioned battery pack model, trolley model and obstacle model are meshed to generate the battery pack finite element model, trolley finite element model and obstacle finite element model, and Establish a ground model with the same height as the lowest point of the trolley, as shown in Figure 5, which constitutes the model for the entire simulation analysis and prepares for subsequent finite element solutions.

In this simulation process, the battery pack material model equation also needs to be given. Among them, the material model equation belongs to the material parameter information of the battery pack model, that is, the stress-strain curve of the upper and lower shells. An example is shown in Figure 2. The material model of the battery pack model is selected during the manufacturing process based on the actual battery pack shell. The stress strain curve of steel is obtained from the material in order to improve the simulation accuracy. Among them, the stress-strain curve is material information measured through special tests and is an inherent property of the material itself.

Based on the above description, for example, given a certain initial speed of a trolley model equipped with a battery pack, such as 15Km/h, and a calculation time of 200ms, the entire process of the bottom of the battery pack hitting the obstacle can be obtained, and the required information can be extracted. Parameters such as: stress strain, amount of intrusion, magnitude of impact force, etc.

During the simulation analysis process of this working condition, due to the finite element mesh division of the simulation model, it is possible to determine the position of each node from the initial position of the trolley with the battery pack under the given collision condition. The movement process of the model when hitting the obstacle can be calculated according to the following process:

Assume that the initial coordinate of a mass point in a fixed Cartesian coordinate system is X _a (a = 1, 2, 3). After a certain time t, the mass point moves to a point in the same coordinate system as X _i (i=1,2,3), due to the consideration of Lagrange's formula, the deformation can be expressed by the equation of coordinates X _a and X _i and time t as:

X _i = _xi (X _a ,t).

In the formula, x _i (X _a ,t) is the position coordinate of the point where the particle moves to the same coordinate system after a certain time t.

At the initial time t=0, the initial state equation can be obtained as:

X _a = _xi (X _a ,0).

Then the initial velocity can be obtained by derivation:

In the formula, is the initial speed,/> is the derivative of the initial position coordinates.

According to the equation of conservation of momentum The solution to the momentum equation that satisfies the boundary conditions is sought:

σ _ij n _i =t _i (t).

In the formula, ρ is the current mass density, f _i is the volume force per unit mass, is the particle acceleration, σ _ij is the Cauchy stress, n _i is the boundary element/> The outer normal line of , t _i (t) is the contact force component at time t.

at the border The displacement boundary conditions are:

D _i (t)= _xi (X _a ,t).

In the formula, D _i (t) is the displacement boundary condition.

at the border When _xi ⁺ = _xi ^- along the inner boundary/> The contact is discontinuous, as:

In the formula, is the maximum value of Cauchy stress,/> is the minimum value of Cauchy stress, xi ₊ is the maximum value of displacement, ^and _xi ^- is the minimum value of displacement.

According to the principle of virtual work, in the physical sense of the collision process, the sum of the internal and external forces acting on the object is equal to zero:

In the formula, is the acceleration component, δ is the displacement component, v _i is the velocity component, t _i is the contact force component, V is the space occupied by the collision system at the current time, D _ij is the component of the deformation rate tensor, and b _i is the volume force component , t _i is the contact force component.

By discretizing the spatial domain V of the collision system with a finite element and adding a virtual displacement field, it can be transformed into a second-order ordinary differential equation, as:

In the formula, M is the mass matrix, ü is the node acceleration vector, F ^int is the node internal force vector, F ^ext is the node external force vector, and F ^c is the contact force and distributed force vector.

Based on the above description, compared with the prior art, the present invention also has the following advantages:

1. The present invention proposes a simulation test method to avoid a large amount of test costs.

2. The present invention packs the battery on a trolley, conducts modeling tests, and uses rigidwall to establish the ground, ensuring that the collision posture of the battery pack during the collision is consistent with the real situation, and solving the problem of excessive cost of using a real vehicle during the test.

3. It provides a feasible solution for dynamic safety simulation testing at the bottom of electric vehicle power battery packs, and plays a positive role in promoting the green and healthy development of new energy.

Furthermore, the collision simulation method of the power battery pack bottom provided by the present invention is used to simulate the collision of the battery pack bottom. Among them, after the Z direction is impacted at the bottom, the battery pack is extruded in the Z direction and is first pushed up to produce positive displacement. The body of the vehicle body is dented due to the extrusion of the battery pack, which first produces negative displacement. The two monitoring points A and B fluctuate continuously during the collision. After the collision and extrusion, due to the end of the plastic deformation stage, the two monitoring points A and B are lifted up a certain distance by the obstacles, as shown in Figure 11. The simulation method provided by the present invention can better simulate the collision posture between the bottom of the battery pack and the obstacle.

Furthermore, the present invention also provides the following implementation structure:

A power battery pack bottom collision simulation system is applied to the power battery pack bottom collision simulation method provided above. The system includes:

3D model building module, used to build battery pack models, trolley models and obstacle models. The battery pack model, trolley model and obstacle model are all three-dimensional models.

The simulation model generation module is used to establish a ground model and form a simulation test model based on the battery pack model, trolley model and obstacle model.

The simulation test module is used to use the simulation test model to conduct a collision simulation test on the bottom of the power battery pack according to the set working condition information to obtain simulation analysis results.

An electronic device including:

Memory, used to store computer programs.

The processor is connected to the memory and is used to retrieve and execute a computer program to implement the power battery pack bottom collision simulation method provided above.

In addition, when the computer program in the above-mentioned memory is implemented in the form of a software functional unit and is sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention essentially or the part that contributes to the existing technology or the part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium, including Several instructions are used to cause a computer device (which can be a personal computer, a server or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage media include: U disk, mobile hard disk, read-only memory, random access memory, magnetic disk or optical disk and other various media that can store program codes.

Each embodiment in this specification is described in a progressive manner. Each embodiment focuses on its differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other. As for the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple. For relevant details, please refer to the description in the method section.

This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and the core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the present invention There will be changes in the specific implementation methods and application scope of the ideas. In summary, the contents of this description should not be construed as limitations of the present invention.

Claims (8)

1. The power battery pack bottom collision simulation method is characterized by comprising the following steps of:

constructing a battery pack model, a trolley model and an obstacle model; the battery pack model, the trolley model and the obstacle model are all three-dimensional models;

establishing a ground model, and forming a simulation test model based on the battery pack model, the trolley model and the obstacle model;

and carrying out a power battery pack bottom collision simulation test according to the set working condition information by adopting the simulation test model to obtain a simulation analysis result.

2. The power cell pack bottom collision simulation method of claim 1, further comprising:

coupling the quality units of the battery pack model to obtain quality points;

and carrying out counterweight on the basis of the mass point so as to simulate the mass of the vehicle to be tested.

3. The power battery pack bottom collision simulation method according to claim 1, wherein a ground model is established, and a simulation test model is formed based on the battery pack model, the trolley model and the obstacle model, specifically comprising:

and carrying out grid division on the battery pack model, the trolley model and the obstacle model by adopting a finite element method to obtain a battery pack finite element model, a trolley finite element model and an obstacle finite element model, and establishing a ground model with the height consistent with the lowest point of the trolley so as to form the simulation test model.

4. The method for simulating the bottom collision of the power battery pack according to claim 3, wherein the simulation test model is adopted to perform the simulation test of the bottom collision of the power battery pack according to the set working condition information to obtain a simulation analysis result, and the method specifically comprises the following steps:

and solving the simulation test model by adopting a variational method to obtain the motion process of the trolley model with the battery pack when the trolley model impacts an obstacle.

5. The method for simulating the bottom collision of the power battery pack according to claim 1, before the simulation test is performed on the bottom collision of the power battery pack according to the set working condition information by using the simulation test model to obtain a simulation analysis result, further comprising:

giving a battery pack material model equation;

and determining a stress-strain curve of the selected material of the battery pack object in the manufacturing process based on the battery pack material model equation.

6. A power battery pack bottom collision simulation system, characterized by being applied to the power battery pack bottom collision simulation method according to any one of claims 1-5; the system comprises:

the three-dimensional model building module is used for building a battery pack model, a trolley model and an obstacle model; the battery pack model, the trolley model and the obstacle model are all three-dimensional models;

the simulation model generation module is used for establishing a ground model and forming a simulation test model based on the battery pack model, the trolley model and the obstacle model;

and the simulation test module is used for carrying out a power battery pack bottom collision simulation test according to the set working condition information by adopting the simulation test model to obtain a simulation analysis result.

7. An electronic device, comprising:

a memory for storing a computer program;

a processor, connected to the memory, for retrieving and executing the computer program to implement the power battery pack bottom collision simulation method according to any one of claims 1-5.

8. The electronic device of claim 7, wherein the memory is a computer-readable storage medium.