Method for determining battery cell simulation model

Abstract

The invention provides a method for determining a battery cell simulation model, and the method comprises the steps: carrying out the collision test of a vehicle based on a preset whole vehicle collision condition, and obtaining a vehicle collision result; determining a first extrusion test matrix of the battery cell based on deformation information of the battery cell in the vehicle collision result; performing an extrusion test on the battery cell based on the first extrusion test matrix to obtain mechanical response characteristics of the battery cell; the first finite element simulation model is calibrated on the basis of the mechanical response characteristics of the battery cell, a second finite element simulation model of the battery cell is obtained, and the first finite element simulation model is a preset initial finite element simulation model of the battery cell. The mechanical response characteristics obtained by the method can more truly reflect the response characteristics of the battery cell in collision, so that the finite element simulation model of the battery cell is calibrated on the basis of the mechanical response characteristics, and the accuracy of the finite element simulation model of the battery cell is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of model simulation, and in particular relates to a method for determining a battery core simulation model. Background Art

[0002] The power battery is a core component of new energy vehicles, and its safety is directly related to vehicle safety. At present, the safety testing of power batteries includes predicting the collision safety failure boundary of the power battery cell (hereinafter referred to as the cell). In the related technology, the collision safety failure boundary of the cell can be determined through real experiments, and the collision safety failure boundary of the cell can also be predicted based on the simulation model. However, relying solely on real experiments to determine the safety failure boundary of the cell will lead to problems such as high test costs and long test cycles. Relying on simulation technology to predict the collision safety failure boundary of the cell can solve the problems brought about by the above-mentioned real experiments. However, in the related technology, the characteristic parameters of the cell are usually obtained based on a single experiment, and the accuracy of the characteristic parameters is poor, resulting in low simulation accuracy of the cell simulation model established with this characteristic parameter. Summary of the invention

[0003] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a method for determining a battery cell simulation model to solve the above-mentioned problems.

[0004] The method for determining a battery cell simulation model provided by the present invention comprises:

[0005] Performing a collision test on the vehicle based on a preset vehicle collision condition to obtain a vehicle collision result;

[0006] Determining a first extrusion test matrix of the battery cell based on deformation information of the battery cell in the vehicle collision result;

[0007] performing an extrusion test on the battery cell based on the first extrusion test matrix to obtain a mechanical response characteristic of the battery cell;

[0008] The first finite element simulation model is calibrated based on the mechanical response characteristics of the battery cell to obtain a second finite element simulation model of the battery cell, wherein the first finite element simulation model is a preset initial finite element simulation model of the battery cell.

[0009] Optionally, the deformation information of the battery cell includes a deformation amount of the battery cell, and determining the first extrusion test matrix of the battery cell based on the deformation information of the battery cell in the vehicle collision result includes:

[0010] Based on the deformation amount and deformation shape of the battery cell, the parameters of N first extrusion heads in the first extrusion test matrix are determined, where N is a positive integer.

[0011] Optionally, the deformation information of the battery cell includes a deformation position of the battery cell, and determining the first extrusion test matrix of the battery cell based on the deformation information of the battery cell in the vehicle collision result includes:

[0012] Based on the deformation positions of the battery cells, squeezed positions of the battery cells in the first squeeze test matrix are determined.

[0013] Optionally, the preset whole vehicle collision condition is determined based on the collision and fire condition of the new energy vehicle, and the preset whole vehicle collision condition includes at least one of the whole vehicle front center pillar collision condition, the whole vehicle side pillar collision condition, the whole vehicle bottom scraping condition and the whole vehicle bottom supporting condition.

[0014] Optionally, before calibrating the first finite element simulation model based on the mechanical response characteristics of the battery cell, the method further includes:

[0015] According to the geometric data corresponding to each component of the battery core, respectively construct a third finite element simulation model corresponding to each component;

[0016] Conducting mechanical tests on each of the components to obtain mechanical response characteristics corresponding to each of the components;

[0017] Based on the mechanical response characteristics corresponding to the components, the third finite element simulation models corresponding to the components are calibrated to obtain fourth finite element simulation models corresponding to the components;

[0018] The first finite element simulation model is constructed based on the fourth finite element simulation model corresponding to each component and the combination relationship of the components constituting the battery core.

[0019] Optionally, each component includes a current collector, a separator and a target component, and the first finite element simulation model is constructed based on the fourth finite element simulation model corresponding to each component and the combination relationship of each component constituting the battery core, including:

[0020] Determine a fifth finite element simulation model of the internal component according to the fourth finite element simulation model of the current collector, the fourth finite element simulation model of the diaphragm, and the combination relationship of the current collector and the diaphragm constituting the internal components of the battery core;

[0021] Performing a mechanical test on the internal component to obtain a mechanical response characteristic of the internal component;

[0022] Calibrate the fifth finite element simulation model according to the mechanical response characteristics of the internal component to obtain a sixth finite element simulation model;

[0023] The first finite element simulation model is constructed based on the sixth finite element simulation model, the fourth finite element simulation model corresponding to the target component, and the combination relationship between the internal component and the target component to form the battery core.

[0024] Optionally, each of the components includes a current collector and a separator, and the method further includes:

[0025] In a process of performing an extrusion test on the battery cell based on the first extrusion test matrix, extracting deformation information of the current collector and the separator;

[0026] The mechanical tests are performed on the components to obtain mechanical response characteristics corresponding to the components, including:

[0027] Determining a second extrusion test matrix based on the deformation information of the current collector and the separator;

[0028] Based on the second extrusion test matrix, extrusion tests are performed on the current collector and the diaphragm respectively to obtain first mechanical response characteristics corresponding to the current collector and the diaphragm.

[0029] Optionally, performing mechanical tests on each of the components to obtain mechanical response characteristics corresponding to each of the components includes:

[0030] Determine the tensile test matrix;

[0031] Based on the tensile test matrix, tensile tests are performed on each component to obtain second mechanical response characteristics corresponding to each component.

[0032] Optionally, each component includes a current collector, a diaphragm, a housing, and a pole, and performing a tensile test on each component based on the tensile test matrix includes:

[0033] Based on the tensile test matrix, tensile tests are performed on the current collector, the separator, the housing and the pole respectively.

[0034] Optionally, after calibrating the first finite element simulation model based on the mechanical response characteristics of the battery cell to obtain the second finite element simulation model of the battery cell, the method further includes:

[0035] Determining a target parameter of the battery cell, wherein the target parameter includes at least one of an electrical performance parameter and a thermal performance parameter of the battery cell;

[0036] Based on the target parameters and the second finite element simulation model, a target finite element simulation model of the battery cell is constructed, and the target finite element simulation model is used for a collision simulation test of the battery cell.

[0037] Beneficial effects of the present technical solution: In the present technical solution, the deformation information of the battery cell in the vehicle collision result can better reflect the deformation of the battery cell in the collision scene when it is put into use. Based on this, the present technical solution determines the first extrusion test matrix through the deformation information of the battery cell in the vehicle collision result, and the extrusion test parameters in the first extrusion test matrix are close to the parameters of the battery cell being extruded in the case of a whole vehicle collision. Therefore, the present technical solution performs an extrusion test on the battery cell through the first extrusion test matrix, and the obtained mechanical response characteristics can more truly reflect the response characteristics of the battery cell in the collision, thereby calibrating the finite element simulation model of the battery cell based on the above-mentioned mechanical response characteristics, which is conducive to improving the accuracy of the finite element simulation model of the battery cell.

[0038] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present application, and together with the specification, are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0040] Figure 1 is a flow chart of a method for determining a battery cell simulation model shown in an exemplary embodiment of the present application;

[0041] Figure 2 is a parameter diagram of a vehicle collision condition shown in an exemplary embodiment of the present application;

[0042] Figure 3 is a schematic diagram of an extrusion test matrix of a battery cell shown in an exemplary embodiment of the present application;

[0043] Figure 4 It is a schematic diagram of a test matrix of various components of a battery cell shown in an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0044] The following will describe the embodiments of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention, not for limiting the scope of protection of the present invention.

[0045] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0046] In the following description, numerous details are discussed to provide a more thorough explanation of the embodiments of the present invention. However, it is obvious to those skilled in the art that the embodiments of the present invention can be implemented without these specific details. In other embodiments, well-known structures and devices are shown in the form of block diagrams rather than in detail to avoid making the embodiments of the present invention difficult to understand.

[0047] In order to more clearly understand the technical solution of the present application, the relevant contents of the present application are explained below.

[0048] The collision safety failure boundary of a battery cell refers to the maximum collision intensity or degree at which the battery cell can maintain its structural integrity, electrical performance and safety performance without serious degradation under certain collision conditions. When the collision intensity exceeds this boundary, the battery cell may have safety problems such as internal short circuit, thermal runaway or electrolyte leakage, and even cause fire or explosion. At present, the method for determining the collision safety failure boundary of a battery cell is generally carried out or derived from the test method specified in GB38031-2020, such as using a semi-cylindrical extrusion head with a radius of 75mm to continuously extrude the battery cell at a fixed speed until the battery cell cell has thermal runaway, and the deformation of the battery cell cell at this time is used as its collision safety failure boundary. However, relying solely on the above test method to determine the collision safety failure boundary of the battery cell will have problems such as high test cost and long cycle. In this regard, there is also a method in the related art to construct a simulation model of the battery cell and use simulation technology to predict the failure boundary of the battery cell. However, in the related art, the characteristic parameters of the battery are usually obtained based on a single test, such as directly extruding the battery cell according to a unified standard extrusion head. Since a single test is difficult to reflect the actual collision scenario of the battery cell after it is put into use, the characteristic parameters obtained based on this test are also difficult to reflect the characteristics of the battery cell in the actual collision scenario, resulting in low simulation accuracy of the battery cell simulation model established based on this characteristic parameter.

[0049] In order to solve the problem of low simulation accuracy of the above-mentioned battery cell simulation model, an embodiment of the present application provides a method for determining a battery cell simulation model.

[0050] See also Figure 1 , Figure 1 FIG. 1 is a flow chart of a method for determining a battery cell simulation model according to an exemplary embodiment of the present application. Figure 1As shown, in an exemplary embodiment, the method for determining the battery cell simulation model includes steps S110 to S140, which are described in detail as follows:

[0051] Step S110, performing a collision test on the vehicle based on a preset vehicle collision condition to obtain a vehicle collision result.

[0052] Step S120: determining a first extrusion test matrix of the battery cell based on the deformation information of the battery cell in the vehicle collision result.

[0053] Step S130: performing an extrusion test on the battery cell based on the first extrusion test matrix to obtain a mechanical response characteristic of the battery cell.

[0054] Step S140, calibrating the first finite element simulation model based on the mechanical response characteristics of the battery cell to obtain a second finite element simulation model of the battery cell, wherein the first finite element simulation model is a preset initial finite element simulation model of the battery cell.

[0055] In step S110, the collision test may be a simulation test, such as pre-building a finite element simulation model of the vehicle, determining a corresponding kinematic model based on a preset whole vehicle collision condition, and performing whole vehicle collision finite element simulation analysis based on the above-mentioned finite element simulation model of the vehicle and the above-mentioned kinematic model, thereby extracting the deformation information of the battery cell. Among them, the battery cell finite element simulation model finally determined in the embodiment of the present application can be mainly used to predict the safe failure boundary of the battery cell. When extracting the deformation information of the battery cell, the deformation information of the battery cell after it is close to failure can be extracted. For example, the prerequisite for extraction may be: the deformation amount in the squeezed direction reaches 15%.

[0056] It is worth mentioning that the above-mentioned preset whole vehicle collision working condition can be one working condition or multiple working conditions. In some embodiments, the collision and fire scenes of new energy vehicles can be analyzed, and the collision speed, collision angle, collision overlap and other information of the vehicles in typical scenes and extreme scenes can be extracted, and the typical whole vehicle collision working condition can be determined as the above-mentioned preset whole vehicle collision working condition.

[0057] By analyzing the collision and fire scenarios of new energy vehicles, four typical vehicle collision conditions can be obtained, namely the front center column collision condition, the vehicle side column collision condition, the vehicle bottom scraping condition and the vehicle bottom supporting condition. The preset vehicle collision conditions in this embodiment may include at least one of the above four typical vehicle collision conditions. Based on the typical vehicle collision conditions, the test is carried out, and the deformation information of the battery cell is obtained to determine the above first extrusion test matrix. The mechanical response characteristics of the battery cell obtained by the test based on the first extrusion test matrix can reflect the response characteristics of the battery cell in a typical vehicle collision scenario.

[0058] Optionally, in order to make the above-mentioned mechanical response characteristics more closely approach the response characteristics of the battery cell in a battery-vehicle collision scenario, the preset whole vehicle collision conditions include the above-mentioned 4 typical whole vehicle collision conditions.

[0059] It is easy to understand that the above-mentioned front center pillar collision condition is that the pillar collides with the front center of the vehicle, the side pillar collision condition is that the pillar collides with the side of the vehicle, the bottom scraping condition is that the bottom of the vehicle is scratched by protrusions, and the bottom supporting condition is that the protrusions at the bottom of the vehicle come into contact with the bottom of the vehicle. The specific collision speed or scratch speed in the above-mentioned conditions can be determined based on the corresponding collision speed or scratch speed in the new energy vehicle fire scene, and the specific collision position or scratch position in the above-mentioned conditions can also be determined based on the corresponding collision position or scratch position in the new energy vehicle fire scene. Among them, refer to Figure 2 As an example, see Figure 2 Set specific parameters corresponding to different working conditions.

[0060] In step S120, a first extrusion test matrix of the battery cell is determined based on the deformation information of the battery cell in the vehicle collision result.

[0061] The deformation information may include the deformation mode type, deformation position, and extrusion direction of the battery cell (a predefined three-dimensional coordinate system, where the extrusion directions are mainly the three directions of X, Y, and Z), etc. Taking the deformation information including the deformation mode type as an example, when the deformation information of the battery cell indicates that the deformation mode type of the large surface A of the battery cell is extrusion depression, the extruded position of the large surface A can be determined as the central area of ​​the large surface A in the first extrusion test matrix; when the deformation information of the battery cell indicates that the deformation mode type of the large surface B of the battery cell is torsion, the extruded position of the large surface B can be determined as the edge area of ​​the large surface B in the first extrusion test matrix.

[0062] In some embodiments, the deformation information of the battery cell includes the deformation amount of the battery cell, and determining the first extrusion test matrix of the battery cell based on the deformation information of the battery cell in the vehicle collision result includes:

[0063] Based on the deformation amount and deformation shape of the battery cell, the parameters of N first extrusion heads in the first extrusion test matrix are determined, where N is a positive integer.

[0064] Among them, the deformation mainly includes the deformation perpendicular to the extruded direction. The shape of the deformation is mainly used to determine the shape of the first extrusion head, and the deformation perpendicular to the extruded direction is mainly used to determine the size of the first extrusion head. For example, when there is a large surface deformation, a cylindrical extrusion head can be used; when there is a small deformation such as angular deformation and sharp corners, a semi-cylindrical extrusion head can be used; when there is an extrusion fracture of the entire side beam, a flat extrusion head can also be used. After determining the type of extrusion head, the size parameters of the corresponding extrusion head can be determined based on the deformation perpendicular to the extruded direction at the deformation point. See Figure 3 , Figure 3 is an example diagram of a first extrusion test matrix exemplarily proposed in this embodiment, such as Figure 3 As shown, the first extrusion test matrix includes parameters of four different extrusion heads.

[0065] The embodiment of the present application determines the parameters of the extrusion head in the first extrusion test matrix based on the deformation amount and deformation shape of the battery cell, which can make the test process close to the collision process of the battery cell in the whole vehicle collision scenario, which is beneficial to improving the accuracy of the above-mentioned mechanical response characteristics.

[0066] In some embodiments, the deformation information of the battery cell includes a deformation position of the battery cell, and determining the first extrusion test matrix of the battery cell based on the deformation information of the battery cell in the vehicle collision result includes:

[0067] Based on the deformation positions of the battery cells, squeezed positions of the battery cells in the first squeeze test matrix are determined.

[0068] The deformation position mainly includes the specific deformation position of the large surface, for example, deformation at the center of the large surface, deformation at the edge of the large surface, deformation near the corner A of the large surface, and deformation near the corner B of the large surface.

[0069] This embodiment determines the squeezed position of the battery cell based on the deformation position of the battery cell, which can make the test process closer to the collision process of the battery cell in the whole vehicle collision scenario, which is conducive to further improving the accuracy of the above-mentioned mechanical response characteristics.

[0070] It is worth pointing out that not all the contents in the first extrusion test matrix are based on the deformation information of the battery cell. Some parameters in the first extrusion test matrix can be determined based on other collision information of the battery cell, or directly based on unified standards or experience. The following first extrusion test matrix is ​​used as an example.

[0071] The extrusion test parameters in the first extrusion test matrix may include the extrusion speed. The extrusion speed may be determined based on the collision speed of the battery cell in the above-mentioned preset vehicle collision condition, so that the test results can more truly reflect the response characteristics of the battery cell in the collision; the extrusion speed may also be determined based on the extrusion speed range in historical experience (see Figure 3 ) to cover more extrusion scenarios.

[0072] The extrusion test parameters in the first extrusion test matrix may also include the angle of the extrusion head (ie, the extrusion plate). Figure 3 As shown, the extrusion head angle can be directly determined based on experience, etc. Among them, when the direction of the cell being extruded is the X direction, and the plane extruded by the extrusion head is the normal plane in the X direction, an extrusion angle of 0° can be considered as the extrusion head plane being parallel to the Y direction in the above normal plane, and an extrusion angle of 90° can be considered as the extrusion head rotating 90 degrees on the normal plane, and its plane being parallel to the Z direction in the above normal plane.

[0073] The extrusion test parameters in the first extrusion test matrix may also include the extrusion form, which may be determined based on experience until thermal runaway occurs. The standard for thermal runaway may refer to the relevant technology or may be customized. In the relevant technology, whether thermal runaway occurs is usually determined only based on strain parameters; the embodiment of the present application may be customized to comprehensively determine whether thermal runaway occurs based on strain parameters and temperature rise rate, so as to improve the accuracy of thermal runaway judgment.

[0074] In step S130, the battery cell is subjected to an extrusion test based on the first extrusion test matrix, and during the test, changes in indicators such as monitoring force, displacement of the battery cell, battery cell voltage and battery cell temperature are collected as basic data for determining the safety failure boundary of the battery cell. Based on the above basic data, the mechanical response characteristics of the battery cell can be obtained, and the mechanical response characteristics mainly include a force-displacement curve.

[0075] In step S140, the first finite element simulation model of the battery cell is calibrated based on the above-mentioned mechanical response characteristics, and the first finite element simulation model after the calibration is completed is the above-mentioned second finite element simulation model. Among them, the first finite element simulation model can be understood as an initial mechanical finite element simulation model pre-constructed in the simulation software (such as Ls-dyna), which has not been calibrated and calibrated by the mechanical response characteristics of the battery cell. In the embodiment of the present application, the mechanical response characteristics mainly include a force-displacement curve, and the calibration of the first finite element simulation model of the battery cell based on the force-displacement curve mainly includes: using the force-displacement curve as the input of the first finite element simulation model, and calibrating the first finite element simulation model according to the displacement output by the first finite element simulation model, until the first finite element simulation model is loaded with the same form of force in the test matrix, the accuracy of the displacement response output by the first finite element simulation model can reach a preset threshold.

[0076] In an embodiment of the present application, an extrusion test is performed on the battery cell through a first extrusion test matrix, and the obtained mechanical response characteristics can more realistically reflect the response characteristics of the battery cell in a collision. Therefore, the finite element simulation model of the battery cell is calibrated based on the above-mentioned mechanical response characteristics, which is beneficial to improving the accuracy of the finite element simulation model of the battery cell.

[0077] Optionally, before calibrating the first finite element simulation model based on the mechanical response characteristics of the battery cell, the method further includes:

[0078] According to the geometric data corresponding to each component of the battery core, respectively construct a third finite element simulation model corresponding to each component;

[0079] Conducting mechanical tests on each of the components to obtain mechanical response characteristics corresponding to each of the components;

[0080] Based on the mechanical response characteristics corresponding to the components, the third finite element simulation models corresponding to the components are calibrated to obtain fourth finite element simulation models corresponding to the components;

[0081] The first finite element simulation model is constructed based on the fourth finite element simulation model corresponding to each component and the combination relationship of the components constituting the battery core.

[0082] In this embodiment, each component may be a main component constituting a battery cell, such as a current collector, a separator, a pole, and a shell.

[0083] In the embodiment of the present application, simulation models of each component of the battery cell are constructed respectively, and the simulation models are calibrated and calibrated. A first finite element simulation model is constructed based on the simulation models of each component after calibration and calibration. Compared with directly constructing the first finite element simulation model based on the geometric data of the battery cell, etc., it is beneficial to improve the simulation accuracy of the first finite element simulation model. In addition, the mechanical response characteristics corresponding to each component are determined respectively. When the structure of the battery cell component changes, battery cell models of different structural forms can be quickly constructed based on the mechanical response characteristics of the above components, and collision simulation analysis can be performed, so that the collision safety failure boundary analysis of batteries with more structural types can be expanded.

[0084] Optionally, each component includes a current collector, a separator and a target component, and the first finite element simulation model is constructed based on the fourth finite element simulation model corresponding to each component and the combination relationship of each component constituting the battery core, including:

[0085] Determine a fifth finite element simulation model of the internal component according to the fourth finite element simulation model of the current collector, the fourth finite element simulation model of the diaphragm, and the combination relationship of the current collector and the diaphragm constituting the internal components of the battery core;

[0086] Performing a mechanical test on the internal component to obtain a mechanical response characteristic of the internal component;

[0087] calibrating the fifth finite element simulation model according to the mechanical response characteristics of the internal component to obtain a sixth finite element simulation model;

[0088] The first finite element simulation model is constructed based on the sixth finite element simulation model, the fourth finite element simulation model corresponding to the target component, and the combination relationship between the internal component and the target component to form the battery core.

[0089] In this embodiment, each component includes a current collector, a diaphragm and a target component. The target component is other components in the core except the current collector and the diaphragm, which may include a shell and a pole, etc. The current collector and the diaphragm are stacked or wound to form the internal parts of the battery cell (also referred to as the core in the related art), and their safety has an important impact on the safety of the battery cell. Based on this, this application separately constructs a simulation model of the core.

[0090] In relevant software, such as Ls-dyna software, a finite element simulation model of the core (i.e., the fifth finite element simulation model) can be established based on the fourth finite element simulation model of the current collector and the fourth finite element simulation model of the diaphragm. By obtaining the mechanical response characteristics of the core, the fifth finite element simulation model can be calibrated to obtain the sixth finite element simulation model.

[0091] Since the core is a relatively important internal component in the battery cell, it has a significant impact on the failure boundary of the battery cell. Based on this, the embodiment of the present application separately constructs a finite element simulation model of the core, and calibrates it. Then, the first finite element simulation model is constructed by the calibrated finite element simulation model of the core and the fourth finite element simulation model of the above-mentioned target component, which is conducive to further improving the accuracy of the first finite element simulation model.

[0092] It is worth mentioning that the process of conducting mechanical tests on the core to obtain the mechanical response characteristics of the core can refer to the embodiment of constructing a first test matrix of the battery cell to test the battery cell, wherein the test matrix corresponding to the core can also refer to Figure 3 The matrices shown are not repeated to avoid duplication.

[0093] Optionally, in a process of performing an extrusion test on the battery cell based on the first extrusion test matrix, deformation information of the current collector and the separator is extracted;

[0094] The mechanical tests are performed on the components to obtain mechanical response characteristics corresponding to the components, including:

[0095] Determining a second extrusion test matrix based on the deformation information of the current collector and the separator;

[0096] Based on the second extrusion test matrix, extrusion tests are performed on the current collector and the diaphragm respectively to obtain first mechanical response characteristics corresponding to the current collector and the diaphragm.

[0097] The closer the mechanical response characteristics of the current collector and the diaphragm are to their response characteristics under a real collision, the higher the accuracy of the fourth finite element simulation model corresponding to the calibrated current collector and the diaphragm. Since the current collector and the diaphragm are important components in the battery cell, the higher the accuracy of the fourth finite element simulation model corresponding to the current collector and the diaphragm, the higher the accuracy of the first finite element simulation model of the battery cell constructed accordingly. Based on this, in the embodiment of the present application, in the extrusion test of the battery cell, the deformation information of the current collector and the diaphragm is extracted, and the second extrusion test matrix is ​​determined based on the deformation information. The first mechanical response characteristics obtained by the test based on the second extrusion test matrix can be closer to its response characteristics under a real collision. Among them, in the above-mentioned embodiment, when the mechanical test is performed on the core separately at the same time, the deformation information of the current collector and the diaphragm can also be extracted in the extrusion test of the core. The battery cell finite element simulation model finally determined in the embodiment of the present application can be mainly used to predict the safe failure boundary of the battery cell. Based on this, when it is necessary to extract deformation information, it can focus on its deformation information when it is close to failure. For example, the prerequisite for extraction can be: the deformation amount in the squeezed direction reaches 15%.

[0098] The deformation information of the current collector and the diaphragm can be the deformation mode and deformation amount of the current collector and the diaphragm. When the large surface and edges of the battery cell or winding core are squeezed, the deformation mode of the current collector and the diaphragm is usually squeezed and concave, and the type of the extrusion head can be determined based on its deformation mode; the deformation amount of the current collector and the diaphragm is mainly the deformation amount perpendicular to the squeezing direction, which is used to determine the size of the extrusion head.

[0099] The embodiment of the present application determines the second extrusion test matrix of the current collector and the diaphragm through the above steps, and conducts tests based on the second extrusion test matrix to obtain the first mechanical response characteristics that are closer to the actual collision scene, which is beneficial to improving the accuracy of the fourth finite element simulation model corresponding to the current collector and the diaphragm respectively.

[0100] Optionally, performing mechanical tests on each of the components to obtain mechanical response characteristics corresponding to each of the components includes:

[0101] Determine the tensile test matrix;

[0102] Based on the tensile test matrix, tensile tests are performed on each component to obtain second mechanical response characteristics corresponding to each component.

[0103] Since the tensile test is a relatively simple and easy test, the embodiment of the present application performs a tensile test on each component separately, which is beneficial to improving the test efficiency and thus is beneficial to improving the efficiency of determining the second mechanical response characteristic.

[0104] Optionally, each component includes a current collector, a diaphragm, a housing, and a pole, and performing a tensile test on each component based on the tensile test matrix includes:

[0105] Based on the tensile test matrix, tensile tests are performed on the current collector, the separator, the housing and the pole respectively.

[0106] Since the current collector, diaphragm, shell and pole are all important components of the battery cell, tensile tests are performed on the current collector, diaphragm, shell and pole respectively, and the corresponding models are calibrated based on the test results, which is conducive to improving the accuracy of the fourth finite element simulation model of the current collector, the fourth finite element simulation model of the diaphragm, the fourth finite element simulation model of the shell and the fourth finite element simulation model of the pole. Among them, in order to facilitate the understanding of the technical solution of the embodiment of the present application, Figure 4 The test matrix of the current collector, diaphragm, shell and pole is shown as an example, including the tensile test matrix of the current collector, diaphragm, shell and pole, and the extrusion test matrix of the current collector and diaphragm. Due to the high importance of the current collector and diaphragm in the battery cell, other related mechanical tests can also be performed on them, such as Figure 4 The shear test matrix used to perform shear tests on current collectors and separators is shown in FIG.

[0107] It is worth mentioning that when the test resources are relatively abundant, the shell and the pole can also be subjected to compression, extrusion and shear tests, and the current collector and the diaphragm can also be subjected to shear tests in addition to the above-mentioned extrusion and tensile tests, which are described in detail below.

[0108] When the battery cell or winding core is squeezed, the shell and the pole may be squeezed and dented; the current collector and the diaphragm may be squeezed and dented, sheared or stretched. The extrusion test matrix of the shell and the pole can be determined by referring to the embodiment of the second extrusion test matrix of the current collector and the diaphragm, and the shell and the pole are subjected to an extrusion test; and the current collector and the diaphragm are subjected to a shear test.

[0109] When the corners of the battery cell or winding core are squeezed, the shell and the pole may be squeezed, twisted or stretched; the current collector and the diaphragm may be squeezed and sheared. The squeeze test matrix of the shell and the pole can be determined by referring to the embodiment of the second squeeze test matrix of the current collector and the diaphragm, and the shell and the pole can be squeezed; and the current collector and the diaphragm can be sheared.

[0110] Optionally, after calibrating the first finite element simulation model based on the mechanical response characteristics of the battery cell to obtain the second finite element simulation model of the battery cell, the method further includes:

[0111] Determining a target parameter of the battery cell, wherein the target parameter includes at least one of an electrical performance parameter and a thermal performance parameter of the battery cell;

[0112] Based on the target parameters and the second finite element simulation model, a target finite element simulation model of the battery cell is constructed, and the target finite element simulation model is used for a collision simulation test of the battery cell.

[0113] The above electrical performance parameters are obtained by conducting electrical performance tests on the battery cells, and the electrical performance parameters include the relationship between voltage, internal resistance and SOC. The above thermal performance parameters are obtained by conducting thermal runaway tests on the battery cells, and the thermal performance parameters include basic thermal parameters and thermal runaway parameters, where the basic thermal parameters include specific heat capacity and thermal conductivity, and the thermal runaway parameters include thermal runaway temperature, thermal runaway time and temperature rise rate.

[0114] The target finite element simulation model in the embodiment of the present application is a single cell multi-physics scenario model: when the target parameters include the above-mentioned electrical performance parameters, according to the second finite element model and the electrical performance parameters, the equivalent circuit model function in the Ls-dyna software is used to construct a single cell mechanical and electrical multi-physics scenario model; when the target parameters include the above-mentioned thermal performance parameters, according to the second finite element model and the thermal performance parameters, the thermal model function and the thermal runaway model function in the Ls-dyna software are used to construct a single cell mechanical and thermal multi-physics scenario model; when the target parameters include the above-mentioned electrical performance parameters and thermal performance parameters, according to the second finite element model, the electrical performance parameters and the thermal performance parameters, the equivalent circuit model function, the thermal model function and the thermal runaway model function in the Ls-dyna software are used to construct a single cell mechanical, electrical and thermal multi-physics scenario model.

[0115] In an embodiment of the present application, the above-mentioned target finite element simulation model is a multi-physics scenario model, which is used for the collision simulation test of the battery cell. On the one hand, it is conducive to improving the accuracy of the simulation results of the collision simulation test; on the other hand, based on the target finite element simulation model, the battery cell can be simulated and analyzed under various collision scenarios, thereby expanding the determination of the collision safety failure boundary of the battery cell in more scenarios.

[0116] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for determining a battery cell simulation model, characterized in that: include: Performing a collision test on the vehicle based on a preset vehicle collision condition to obtain a vehicle collision result; Determining a first extrusion test matrix of the battery cell based on deformation information of the battery cell in the vehicle collision result; performing an extrusion test on the battery cell based on the first extrusion test matrix to obtain a mechanical response characteristic of the battery cell; The first finite element simulation model is calibrated based on the mechanical response characteristics of the battery cell to obtain a second finite element simulation model of the battery cell, wherein the first finite element simulation model is a preset initial finite element simulation model of the battery cell.

2. The method according to claim 1, characterized in that The deformation information of the battery cell includes a deformation amount and a deformation shape of the battery cell. The step of determining a first extrusion test matrix of the battery cell based on the deformation information of the battery cell in the vehicle collision result includes: Based on the deformation amount and deformation shape of the battery cell, the parameters of N first extrusion heads in the first extrusion test matrix are determined, where N is a positive integer.

3. The method according to claim 1, characterized in that The deformation information of the battery cell includes the deformation position of the battery cell, and the determining of the first extrusion test matrix of the battery cell based on the deformation information of the battery cell in the vehicle collision result includes: Based on the deformation positions of the battery cells, squeezed positions of the battery cells in the first squeeze test matrix are determined.

4. The method according to any one of claims 1 to 3, characterized in that The preset whole vehicle collision condition is determined based on the collision and fire condition of the new energy vehicle, and the preset whole vehicle collision condition includes at least one of the whole vehicle front center pillar collision condition, the whole vehicle side pillar collision condition, the whole vehicle bottom scraping condition and the whole vehicle bottom supporting condition.

5. The method according to claim 1, characterized in that Before calibrating the first finite element simulation model based on the mechanical response characteristics of the battery cell, the method further includes: According to the geometric data corresponding to each component of the battery core, respectively construct a third finite element simulation model corresponding to each component; Conducting mechanical tests on each of the components to obtain mechanical response characteristics corresponding to each of the components; Based on the mechanical response characteristics corresponding to the components, the third finite element simulation models corresponding to the components are calibrated to obtain fourth finite element simulation models corresponding to the components; The first finite element simulation model is constructed based on the fourth finite element simulation model corresponding to each component and the combination relationship of the components constituting the battery core.

6. The method according to claim 5, characterized in that The components include a current collector, a separator and a target component. The first finite element simulation model is constructed based on the fourth finite element simulation model corresponding to the components and the combination relationship of the components constituting the battery core, including: Determine a fifth finite element simulation model of the internal component according to the fourth finite element simulation model of the current collector, the fourth finite element simulation model of the diaphragm, and the combination relationship of the current collector and the diaphragm constituting the internal components of the battery core; Performing a mechanical test on the internal component to obtain a mechanical response characteristic of the internal component; calibrating the fifth finite element simulation model according to the mechanical response characteristics of the internal component to obtain a sixth finite element simulation model; The first finite element simulation model is constructed based on the sixth finite element simulation model, the fourth finite element simulation model corresponding to the target component, and the combination relationship between the internal component and the target component to form the battery core.

7. The method according to claim 5, characterized in that Each component includes a current collector and a separator, and the method further includes: In a process of performing an extrusion test on the battery cell based on the first extrusion test matrix, extracting deformation information of the current collector and the separator; The mechanical tests are performed on the components to obtain mechanical response characteristics corresponding to the components, including: Determining a second extrusion test matrix based on the deformation information of the current collector and the separator; Based on the second extrusion test matrix, extrusion tests are performed on the current collector and the diaphragm respectively to obtain first mechanical response characteristics corresponding to the current collector and the diaphragm.

8. The method according to any one of claims 5 to 7, characterized in that The mechanical tests are performed on the components to obtain mechanical response characteristics corresponding to the components, including: Determine the tensile test matrix; Based on the tensile test matrix, tensile tests are performed on each component to obtain second mechanical response characteristics corresponding to each component.

9. The method according to claim 8, characterized in that Each component includes a current collector, a diaphragm, a housing and a pole, and performing a tensile test on each component based on the tensile test matrix includes: Based on the tensile test matrix, tensile tests are performed on the current collector, the separator, the housing and the pole respectively.

10. The method according to claim 1, characterized in that After calibrating the first finite element simulation model based on the mechanical response characteristics of the battery cell to obtain the second finite element simulation model of the battery cell, the method further includes: Determining a target parameter of the battery cell, wherein the target parameter includes at least one of an electrical performance parameter and a thermal performance parameter of the battery cell; Based on the target parameters and the second finite element simulation model, a target finite element simulation model of the battery cell is constructed, and the target finite element simulation model is used for a collision simulation test of the battery cell.

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