A method and apparatus for determining the structural stress of structural components in a battery.

Abstract

This application provides a method and apparatus for determining the structural stress of structural components in a battery. The method includes: determining the expansion stress of cells at different locations in the battery based on temperature change data of the battery under test during charging and discharging, the cell expansion force of the battery under test at different temperatures, the cell material parameters of the battery under test, and the position information of each cell in the battery under test; and for a cell at any location in the battery under test, determining the structural stress exerted on the structural component by the expansion stress based on the cell's expansion stress and the preset degree of freedom information of the structural component within a preset threshold distance from the cell. This application not only enables real-time monitoring of cell expansion stress and structural stress but also reduces the risk of structural component damage, improves the overall safety and sealing of the battery, and ensures the driving safety of new energy vehicles.

Description

Technical Field

[0001] This application relates to the field of new energy technology, and in particular to a method and apparatus for determining the structural stress of structural components in a battery. Background Technology

[0002] With social development and technological progress, the application of new energy vehicles is becoming more and more widespread, and batteries, as the power supply devices for new energy vehicles, have also developed rapidly. As a result, a large number of battery types and companies have entered the market.

[0003] As one of the three main components of new energy vehicles, the performance of batteries is receiving increasing attention from customers and the public. During normal battery use, the expansion force of the battery cell or cell module changes constantly with the charging and discharging of the cells or cell modules. Especially in the later stages, the expansion force of some types of cells is very large, often reaching tens of kilonewtons, particularly in the end area of ​​the module. This expansion force poses a huge challenge to the structural stress of other structural components in the battery besides the cells. Traditionally, the testing of cell expansion stress and structural component stress is usually verified in the later stages of battery research and development. This not only delays the product development process and increases development costs, but also, if the cell expansion force is too large, it can damage other structural components outside the cell, and even affect the safety and sealing of the entire battery, thus affecting the driving safety of new energy vehicles. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a method and apparatus for determining the structural stress of structural components in a battery, which not only realizes the real-time monitoring of the expansion stress and structural stress of the battery cell, but also reduces the risk of structural component damage, improves the overall safety and sealing of the battery, and ensures the driving safety of new energy vehicles.

[0005] This application provides a method for determining the structural stress of structural components in a battery, the method comprising:

[0006] The system acquires temperature change data of the battery under test during charging and discharging, cell expansion force of the battery under test at different temperatures, cell material parameters of the battery under test, and position information of each cell in the battery under test.

[0007] Based on the temperature change data, the cell material parameters, the location information, and the cell expansion force, the expansion stress of the cell at different locations in the battery under test is determined.

[0008] For any cell in the battery under test, the structural stress exerted by the expansion stress of the cell on the structural component is determined based on the expansion stress of the cell and the preset degree of freedom information of the structural component within a preset threshold distance from the cell.

[0009] Furthermore, determining the expansion stress of the battery cell at different locations in the battery under test based on the temperature change data, the cell material parameters, the location information, and the cell expansion force includes:

[0010] The battery to be tested is divided into units and nodes according to a grid, and the corresponding units and nodes of the battery to be tested are determined.

[0011] The battery to be tested is divided into matrices according to the finite element method to determine the matrix data corresponding to the battery to be tested.

[0012] Based on the preset cell expansion force, the stiffness matrix in the cell material parameters, and the position information, the displacement information at each node of the cell is determined;

[0013] Based on the displacement information, temperature change data, and material parameters of the battery cell at each node, the expansion stress of the battery cell at different locations in the battery under test is determined.

[0014] Furthermore, the cell material parameters include the cell stack expansion coefficient. The determination of the expansion stress of the cell at different locations in the battery under test, based on displacement information, temperature change data, and the cell material parameters at each node of the cell, includes:

[0015] Based on the displacement information at each node of the battery cell, the strain information of the battery cell structure under the action of battery cell expansion force at different locations is determined.

[0016] Based on the strain information of each cell structure, temperature change data, and cell stack expansion coefficient, the expansion stress of the cell at different locations in the battery under test is determined.

[0017] Furthermore, the matrixed data corresponding to the battery to be tested includes the geometric structure matrix of the cell. The determination of the cell structure strain information at different locations under the action of cell expansion force, based on the displacement information at each node of the cell, includes:

[0018] Based on the displacement information at each node of the battery cell and the geometric structure matrix, the strain information of the battery cell structure under the action of battery cell expansion force at different locations is determined.

[0019] Furthermore, the matrixed data corresponding to the battery under test also includes an elastic matrix. The determination of the expansion stress of the battery cells at different locations within the battery under test, based on the strain information of each cell structure, temperature change data, and the cell stack expansion coefficient, includes:

[0020] Based on temperature change data and the cell lamination expansion coefficient, the cell temperature strain information of the battery cell is determined;

[0021] Based on the cell temperature strain information, the strain information of each cell structure, and the elastic matrix corresponding to the battery under test, the expansion stress of the cell at different locations in the battery under test is determined.

[0022] Furthermore, the preset degree-of-freedom information of the structural component includes the boundary contact force of the structural component. For any cell in the battery under test, the structural stress exerted on the structural component by the expansion stress of the cell is determined based on the expansion stress of the cell and the preset degree-of-freedom information of the structural component within a preset threshold distance from the cell. This includes:

[0023] For any cell in the battery under test, the structural stress exerted by the expansion stress of the cell on the structural component is determined based on the expansion stress of the cell and the contact force of the structural component boundary with the structural component within a preset threshold distance of the cell.

[0024] Furthermore, after determining the structural stress exerted on the structural component by the expansion stress of the battery cell on the structural component based on the expansion stress of the battery cell and the preset degree of freedom information of the structural component within a preset threshold distance from the battery cell, the method for determining the structural stress of the structural component in the battery further includes:

[0025] Based on the structural stress of the structural component, the strain type of the structural component is determined, wherein the strain type includes elastic strain and / or plastic strain.

[0026] This application embodiment also provides a device for determining the structural stress of structural components in a battery, the device comprising:

[0027] The acquisition module is used to acquire temperature change data of the battery under test during the charging and discharging process, cell expansion force of the battery under test at different temperatures, cell material parameters of the battery under test, and position information of each cell in the battery under test.

[0028] The first determining module is used to determine the expansion stress of the battery cell at different locations in the battery under test based on the temperature change data, the battery cell material parameters, the position information, and the battery cell expansion force.

[0029] The second determining module is used to determine, for any location in the battery under test, the structural stress exerted by the expansion stress of the battery cell on the structural component based on the expansion stress of the battery cell and the preset degree of freedom information of the structural component within a preset threshold distance from the battery cell.

[0030] This application embodiment also provides an electronic device, including: a processor, a memory, and a bus. The memory stores machine-readable instructions executable by the processor. When the electronic device is running, the processor communicates with the memory via the bus. When the machine-readable instructions are executed by the processor, the steps of the structural stress determination method for structural components in a battery as described above are performed.

[0031] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, performs the steps of the method for determining the structural stress of structural components in a battery as described above.

[0032] The method and apparatus for determining the structural stress of structural components in a battery provided in this application, compared with those in the prior art, determine the expansion stress of the battery cell at different locations in the battery under test by using temperature change data, cell material parameters, location information, and cell expansion force. Based on the expansion stress of the battery cell and the preset degree of freedom information of the structural components within a preset threshold distance from the battery cell, the structural stress exerted by the expansion stress of the battery cell on the structural components is determined. This not only realizes the real-time monitoring of the expansion stress and structural stress of the battery cell, but also reduces the risk of structural component damage, improves the safety and sealing of the entire battery, and ensures the driving safety of new energy vehicles.

[0033] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0034] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1This invention provides a flowchart of one of the methods for determining the structural stress of a structural component in a battery, according to an embodiment of this application.

[0036] Figure 2 This illustration shows a schematic diagram of the structure of the battery under test in a method for determining the structural stress of a structural component in a battery according to an embodiment of this application.

[0037] Figure 3 This document shows a second flowchart of a method for determining the structural stress of a structural component in a battery, as provided in an embodiment of this application.

[0038] Figure 4 This paper shows a structural block diagram of a device for determining the structural stress of a structural component in a battery, provided in an embodiment of this application.

[0039] Figure 5 A schematic diagram of the structure of an electronic device provided in an embodiment of this application is shown.

[0040] In the picture:

[0041] 400 - Structural stress determination device; 410 - Acquisition module; 420 - First determination module; 430 - Second determination module; 440 - Judgment module; 500 - Electronic device; 510 - Processor; 520 - Memory; 530 - Bus. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. Based on the embodiments of this application, every other embodiment obtained by those skilled in the art without inventive effort falls within the scope of protection of this application.

[0043] First, the applicable scenarios for this application will be introduced. This application can be applied to the field of new energy technology.

[0044] Research has shown that batteries, as one of the three main components of new energy vehicles, are receiving increasing attention from customers and the public regarding their performance. During normal battery use, the expansion force of the battery cells or modules constantly changes with charging and discharging. Especially towards the end, some types of cells experience extremely high expansion forces, often reaching tens of kilonewtons, particularly in the module's end area. This expansion force poses a significant challenge to the structural stress of other components within the battery besides the cells. Traditionally, testing for cell expansion stress and structural component stress is only conducted in the later stages of battery development. This not only delays product development and increases development costs, but also, if the cell expansion force is too high, it can damage other structural components outside the cell, potentially affecting the overall battery safety and sealing, and ultimately impacting the driving safety of new energy vehicles.

[0045] Based on this, the embodiments of this application provide a method and apparatus for determining the structural stress of structural components in a battery, which not only realizes the real-time monitoring of the expansion stress and structural stress of the battery cell, but also reduces the risk of structural component damage, improves the overall safety and sealing of the battery, and ensures the driving safety of new energy vehicles.

[0046] Please see Figure 1 , Figure 1 This is one of the flowcharts for a method of determining the structural stress of a structural component in a battery, provided in an embodiment of this application. Figure 1 As shown in the embodiments of this application, the method for determining the structural stress of structural components in a battery includes the following steps:

[0047] S101. Obtain temperature change data of the battery under test during charging and discharging, cell expansion force of the battery under test at different temperatures, cell material parameters of the battery under test, and position information of each cell in the battery under test.

[0048] In this step, during the charging and discharging process of the battery under test, the temperature change data, the cell expansion force at different temperatures, the cell material parameters, and the position information of each cell within the battery under test are acquired. The cells will expand. If the expansion stress of the cells is too high, it will cause other structural components in the battery under test, besides the cells or resistor modules, to be squeezed, deformed, or even damaged. Here, the other structural components in the embodiments provided in this application include, but are not limited to, busbars, end plates, thermally conductive structural adhesive for the cells, buffers between cells, and the battery casing. Therefore, to determine the structural stress exerted by the cell expansion stress on the structural components, a structural analysis of the battery under test, including the cells, is required. Thus, it is necessary to first acquire the temperature change data, the cell expansion force at different temperatures, the cell material parameters, and the position information of each cell within the battery under test.

[0049] In the embodiments provided above, the battery under test in this application will transmit the expansion force generated by the internal expansion of the battery cell to other structural components in the battery under test. Therefore, this application simulates the battery cell in the early stage of product development, so that the battery system energy is reduced to 80% of the initial energy. At this time, the battery cell expansion is large and the battery cell expansion stress is large. Therefore, the embodiments provided in this application test the battery under test in the early stage, and adjust and optimize the corresponding structural components in real time according to the test results. The adjustment and optimization of the corresponding structural components in the embodiments provided in this application specifically includes, but is not limited to, checking the bolt preload and checking the structural stress. This application provides optimization and modification of the battery under test to make it meet the development requirements of the battery under test.

[0050] Here, in the embodiments of this application, the water-cooling plate in the battery under test, excluding the battery cell, is made of aluminum, the thermally conductive adhesive of the battery cell uses parameters under normal temperature conditions, and the busbar, end plate, and water-cooling plate materials need to take into account material nonlinearity.

[0051] Furthermore, when performing expansion analysis on the battery under test, it is necessary to set the parameters of the key structural components in the battery under test. For example, the density of the water cooling plate is set to 2.77e-09t / mm^3, the elastic modulus is set to 69120MPa, and the Poisson's ratio is set to 0.33; the density of the end plate is set to 1.55e-09t / mm^3, and the elastic modulus is set to 14500MPa.

[0052] Please see Figure 2 , Figure 2 This is a schematic diagram of the structure of the battery under test in a method for determining the structural stress of structural components in a battery, as provided in an embodiment of this application. Figure 2As shown in the embodiment of this application, the battery to be tested in the structural stress determination method for structural components in a battery includes a cell, a busbar, and a casing.

[0053] S102. Based on the temperature change data, the cell material parameters, the location information, and the cell expansion force, determine the expansion stress of the cell at different locations in the battery to be tested.

[0054] In this step, cell expansion analysis is performed on the battery under test. The main idea is that the chemical thermal energy of the cell changes during charging and discharging, that is, the temperature changes. Therefore, based on the temperature change data of the cell during the expansion process, the cell material parameters, the position information of each cell in the battery under test, and the cell expansion force during charging and discharging, the expansion stress of the cell at different positions in the battery under test is determined.

[0055] Here, the battery cell material parameters provided in the embodiments of this application include, but are not limited to, the elastic modulus of the battery cell in three spatial directions, the Poisson's ratio of the battery cell, the shear modulus of the battery cell, the coefficient of thermal expansion of the battery cell, and the overall density of the battery cell.

[0056] Among them, the elastic modulus is used to characterize the stress divided by the strain in that direction under uniaxial stress state, and is a physical quantity that describes the elasticity of a material; Poisson's ratio is used to characterize the ratio of the absolute value of the transverse normal strain to the axial normal strain when a material is under uniaxial tension or compression, and is also called the transverse deformation coefficient, which is an elastic constant that reflects the transverse deformation of the material; the shear modulus is used to characterize the material constant, and is the ratio of shear stress to strain, also known as the shear modulus or rigidity modulus.

[0057] Thus, in the embodiments provided in this application, the overall density of the battery cell is specifically 2.7e-09t / mm^3; the elastic modulus of the battery cell in the three spatial directions is specifically 60 MPa; the Poisson's ratio of the battery cell is specifically 0.2; the shear modulus of the battery cell is specifically 25; and the temperature expansion coefficients of the battery cell in the X / Y / Z directions are 1e-07, 5.02e-06, and 1.1e-07, respectively.

[0058] Optionally, step S102 includes the following sub-steps:

[0059] Sub-step 1021: Divide the battery to be tested into units and nodes according to the grid, and determine each unit corresponding to the battery to be tested and each node corresponding to each unit.

[0060] In this step, before performing a simulated expansion stress analysis on the battery under test, the battery under test is first converted from a geometric model to a simulation model using third-party simulation software. At the same time, the battery under test is divided into units and nodes according to the mesh, and the corresponding units and nodes of each unit are determined.

[0061] Sub-step 1022: Divide the battery to be tested into a matrix using the finite element method to determine the matrix data corresponding to the battery to be tested.

[0062] In this step, a preset finite element algorithm is used to perform matrix partitioning of the data of the battery under test, and to determine the matrix data corresponding to the input data of the battery under test.

[0063] Here, Finite Element Analysis (FEA) is used to characterize and simulate real physical systems (geometry and load conditions) using mathematical approximations. It also utilizes simple, interacting elements, or units, to approximate a real system with an infinite number of unknowns using a finite number of unknowns.

[0064] Sub-step 1023: Determine the displacement information at each node of the battery cell based on the preset cell expansion force, the stiffness matrix in the cell material parameters, and the position information.

[0065] In this step, the displacement information at each node of the battery cell in the embodiments provided in this application includes, but is not limited to, the displacement column vector and the column vector of the external load.

[0066] The specific formula for determining the displacement information at each node of the battery cell provided in this application is as follows:

[0067] {δ}e=[K]-1{F};

[0068] Here, {δ}e is used to characterize the displacement information at each node of the battery cell, specifically the displacement matrix of the battery cell at each node; [K] is used to characterize the stiffness matrix; and {F} is used to characterize the preset battery cell expansion force.

[0069] Sub-step 1024: Based on the displacement information, temperature change data and material parameters of each node of the cell, determine the expansion stress of the cell at different locations in the battery to be tested.

[0070] In this step, the cell material parameters include the cell stack expansion coefficient, which is determined based on the lithium deposition pattern of the cell during the charging and discharging process.

[0071] Here, lithium plating is used to characterize a loss condition of lithium-ion batteries. Specifically, lithium-ion batteries cannot be charged in environments with temperatures below 0°C. Although the charging may appear normal, metallic lithium will be deposited on the anode surface. This process is irreversible. Repeated charging at low temperatures will damage the battery and reduce its safety, especially when subjected to external pressure and impact.

[0072] In the embodiments provided in this application, different cell stacking expansion coefficients can be set for cells at different locations based on the expansion of the cells at different locations, and generally the direction of maximum expansion of the cell is the thickness direction of the cell.

[0073] The above sub-step 1024 includes the following sub-steps:

[0074] Sub-step 10241: Based on the displacement information at each node of the battery cell, determine the strain information of the battery cell structure at different locations under the action of battery cell expansion force.

[0075] Optionally, the matrixed data corresponding to the battery to be tested includes the geometric structure matrix of the battery cell. The determination of the cell structure strain information at different locations under the action of cell expansion force, based on the displacement information at each node of the battery cell, includes:

[0076] Based on the displacement information at each node of the battery cell and the geometric structure matrix, the strain information of the battery cell structure under the action of battery cell expansion force at different locations is determined.

[0077] Here, the formula for the expansion stress of the cell at different locations in the battery under test is specifically as follows:

[0078] {ε}=[B]{δ}e;

[0079] Here, {δ}e is used to characterize the displacement information at each node of the battery cell, specifically the displacement matrix at each node of the battery cell; [B] is used to characterize the geometric structure matrix; and {ε} is used to characterize the strain information of the battery cell structure under the action of the battery cell expansion force.

[0080] Sub-step 10242: Based on the strain information of each cell structure, temperature change data, and cell stack expansion coefficient, determine the expansion stress of the cell at different locations in the battery under test.

[0081] In this step, the matrixed data corresponding to the battery under test also includes an elastic matrix. Determining the expansion stress of the battery cells at different locations within the battery under test based on the strain information of each cell structure, temperature change data, and the cell stack expansion coefficient includes:

[0082] Based on temperature change data and the cell lamination expansion coefficient, the cell temperature strain information is determined.

[0083] Here, the formula for determining the expansion stress of the battery cell at different locations in the battery under test in the embodiments provided in this application is specifically as follows:

[0084] {ε0}=αT[1 1 0]T;

[0085] Here, α is used to characterize the cell lamination expansion coefficient; T is used to characterize temperature change data.

[0086] Based on the cell temperature strain information, the strain information of each cell structure, and the elastic matrix corresponding to the battery under test, the expansion stress of the cell at different locations in the battery under test is determined.

[0087] Here, based on Hooke's law, cell temperature strain information, strain information of each cell structure, and the elastic matrix corresponding to the battery under test, a geometric equation is formed to determine the expansion stress of the cell at different locations in the battery under test.

[0088] The formula for determining the expansion stress of the battery cell at different locations in the battery under test, provided in the embodiments of this application, is as follows:

[0089] {σ}=[D]([B]{δ}e-{ε0});

[0090] Thus, {σ} is used to characterize the expansion stress of the cell at different locations in the battery under test (determined using Gaussian integration); [D] is used to characterize the elastic matrix corresponding to the battery under test; [B] is used to characterize the geometric structure matrix; {ε} is used to characterize the cell structure strain information under the action of cell expansion force; {ε0} is used to characterize the expansion stress of the cell at different locations in the battery under test; and e is used to characterize the general elastic modulus.

[0091] S103. For the cell at any location in the battery to be tested, determine the structural stress exerted by the expansion stress of the cell on the structural component based on the expansion stress of the cell and the preset degree of freedom information of the structural component within a preset threshold distance from the cell.

[0092] In this step, the preset degree of freedom information of the structural component includes the boundary contact force of the structural component, and step S103 includes the following sub-steps:

[0093] Sub-step 1031: For the cell at any location in the battery to be tested, determine the structural stress exerted by the expansion stress of the cell on the structural component based on the expansion stress of the cell and the contact force of the structural component boundary with the structural component within a preset threshold distance of the cell.

[0094] Here, based on the expansion stress of the battery cell and the connection relationship and boundary between the battery cell and the structural components (i.e., the contact force of the structural component boundary within the preset threshold distance of the battery cell), the structural stress of each structural component within the preset threshold distance of the battery cell can be calculated. This allows for the determination of the stress state of each structural component in the battery under test, and the detection of whether the use of each structural component is suitable for the corresponding application scenario. Furthermore, if the use of any structural component is not suitable for the corresponding application scenario, the corresponding structural component can be optimized and adjusted in a timely manner to meet the design requirements of the battery under test. This greatly reduces the R&D cost and has a positive effect on the safety and service life of the entire battery pack under test.

[0095] Among them, the preset degree of freedom information can represent, but is not limited to, the number of spatial coordinates.

[0096] In the above-described embodiments, the embodiment provided in this application employs an explicit method for structural component boundary contact forces, which can be specifically described as follows:

[0097] Since cell expansion occurs within a certain timeframe, the stress on structural components is examined by measuring the expansion force of the cell during this time. Interface settings for each structural component are also implemented. For example, the liquid cooling plate is bonded to the cell using thermally conductive adhesive, requiring binding interface constraints (i.e., preset degrees of freedom) between the liquid cooling plate and the adhesive, and between the adhesive and the cell. Similarly, if the end plate has a contact interface with the inner side of the casing, contact needs to be established between the two parts to simulate a real-world environment. Furthermore, since the entire battery under test is bolted to the vehicle, constraints (degrees of freedom 1-6) are applied at the connection between the battery and the bolts to accelerate calculations, assuming a high vehicle stiffness. Considering the cell's expansion characteristics with temperature changes, a temperature load is applied to the model to perform thermal stress analysis. The parameters mentioned in this application can be customized and set according to different application scenarios.

[0098] Specifically, the tool for controlling the structural stress of each structural component within the preset threshold distance of the battery cell can be as follows:

[0099] {σs}={σ}-{Psc};

[0100] Here, {σ} is used to characterize the expansion stress of the battery cell; {Psc} is used to characterize the contact force at the boundary of the structural component within a preset threshold distance of the core.

[0101] The method for determining the structural stress of structural components in a battery provided in this application, compared with the prior art, determines the expansion stress of the battery cell at different locations in the battery under test by using temperature change data, cell material parameters, location information, and cell expansion force. Based on the expansion stress of the battery cell and the preset degree of freedom information of the structural components within a preset threshold distance from the battery cell, the method determines the structural stress exerted on the structural components by the expansion stress of the battery cell. This not only enables real-time monitoring of the expansion stress and structural stress of the battery cell, but also reduces the risk of structural component damage, improves the overall safety and sealing of the battery, and ensures the driving safety of new energy vehicles.

[0102] Please see Figure 3 , Figure 3 This is a second flowchart illustrating a method for determining the structural stress of a structural component in a battery, provided as an embodiment of this application. Figure 3 As shown in the embodiments of this application, the method for determining the structural stress of structural components in a battery includes the following steps:

[0103] S301. Obtain temperature change data of the battery under test during charging and discharging, cell expansion force of the battery under test at different temperatures, cell material parameters of the battery under test, and position information of each cell in the battery under test.

[0104] S302. For the cell at any location in the battery to be tested, determine the structural stress exerted by the expansion stress of the cell on the structural component based on the expansion stress of the cell and the preset degree of freedom information of the structural component within a preset threshold distance from the cell.

[0105] S303. For the cell at any location in the battery to be tested, determine the structural stress exerted by the expansion stress of the cell on the structural component based on the expansion stress of the cell and the preset degree of freedom information of the structural component within a preset threshold distance from the cell.

[0106] S304. Based on the structural stress of the structural component, determine the strain type of the structural component, wherein the strain type includes elastic strain and / or plastic strain.

[0107] In this step, based on the structural stress of the structural component, it is determined whether the structural stress of the structural component is greater than the preset structural stress of the structural component. If it is greater, the strain type of the structural component is determined.

[0108] Furthermore, the specific formula for the strain of the structural component is as follows:

[0109] {εs}=[E]-1{σ};

[0110] Where {εs} is used to characterize the strain of the structural component; [E] is used to characterize the elastic modulus of the structural component.

[0111] Here, the strain type of the structural component is determined using the following method:

[0112] First, determine the structural strain of the structural component.

[0113] If the structural strain is less than or equal to the structural strain threshold, then the strain type corresponding to the structural component is elastic strain.

[0114] If the structural strain is greater than the structural strain threshold, then the strain type corresponding to the structural component is plastic strain.

[0115] In this process, the material of the structural component will gradually enter the plastic stage after experiencing the elastic stage under the action of external load.

[0116] Thus, the embodiments provided in this application illustrate the structural stresses of specific structural components, as follows:

[0117] When the end expansion force of the battery under test is 28000N, the maximum stress of the casing is 123.7MPa, which is less than the threshold of 275MPa; the maximum stress of the cell casing is 155.2MPa, which is less than the threshold of 165MPa; the maximum stress of the liquid cooling plate is 82.5MPa, which is less than the threshold of 137MPa; and the maximum stress of the busbar is 43.9MPa, which is less than 73MPa. That is, under the condition that the cell applies an end expansion force of 28000N to the end plate, each component meets the design requirements; at the same time, the maximum deformation of the casing is 0.57mm, which is less than the threshold of 0.8mm, meeting the sealing requirements, as shown in Table 1. Table 1 shows the structural stress of each structural component.

[0118] Table 1

[0119]

[0120] Furthermore, the method for optimizing the battery to be tested provided in this application can be specific, but is not limited to, the following:

[0121] If the structural stress of a structural component exceeds the structural strain threshold by less than 10%, morphology or shape optimization can be performed to improve stiffness and reduce the stress or strain of the structural component by changing the morphology.

[0122] If the structural stress of a structural component exceeds the structural strain threshold by about 10%-30%, it can be optimized by adjusting the thickness and shape.

[0123] If the structural stress of a structural component exceeds the structural strain threshold by more than 30%, it can generally be optimized by adding reinforcing components or changing the material of the structural component.

[0124] The descriptions of S301 to S303 can be referred to the descriptions of S101 to S103, and can achieve the same technical effect, so they will not be elaborated further.

[0125] The method for determining the structural stress of structural components in a battery provided in this application, compared with the prior art, determines the expansion stress of the battery cell at different locations in the battery under test by using temperature change data, cell material parameters, location information, and cell expansion force. Based on the expansion stress of the battery cell and the preset degree of freedom information of the structural components within a preset threshold distance from the battery cell, the method determines the structural stress exerted on the structural components by the expansion stress of the battery cell. This not only enables real-time monitoring of the expansion stress and structural stress of the battery cell, but also reduces the risk of structural component damage, improves the overall safety and sealing of the battery, and ensures the driving safety of new energy vehicles.

[0126] Please see Figure 4 , Figure 4 This is a structural block diagram of a device for determining the structural stress of a structural component in a battery, provided as an embodiment of this application. Figure 4 As shown, the structural stress determination device 400 for structural components in the battery includes:

[0127] The acquisition module 410 is used to acquire temperature change data of the battery under test during the charging and discharging process, cell expansion force of the battery under test at different temperatures, cell material parameters of the battery under test, and position information of each cell in the battery under test.

[0128] The first determining module 420 is used to determine the expansion stress of the battery cell at different locations in the battery under test based on the temperature change data, the battery cell material parameters, the position information, and the battery cell expansion force.

[0129] Optionally, the first determining module 420 is specifically used for:

[0130] The battery to be tested is divided into units and nodes according to a grid, and the corresponding units and nodes of the battery to be tested are determined.

[0131] The battery to be tested is divided into matrices using the finite element method to determine the matrix data corresponding to the battery to be tested.

[0132] Based on the preset cell expansion force, the stiffness matrix in the cell material parameters, and the position information, the displacement information at each node of the cell is determined.

[0133] Based on the displacement information, temperature change data, and material parameters of the battery cell at each node, the expansion stress of the battery cell at different locations in the battery under test is determined.

[0134] Optionally, the cell material parameters include the cell stack expansion coefficient. The step of determining the expansion stress of the cell at different locations in the battery under test based on displacement information, temperature change data, and the cell material parameters at each node of the cell includes:

[0135] Based on the displacement information at each node of the battery cell, the strain information of the battery cell structure under the action of battery cell expansion force at different locations is determined.

[0136] Optionally, the matrixed data corresponding to the battery to be tested includes the geometric structure matrix of the battery cell. The determination of the cell structure strain information at different locations under the action of cell expansion force, based on the displacement information at each node of the battery cell, includes:

[0137] Based on the displacement information at each node of the battery cell and the geometric structure matrix, the strain information of the battery cell structure under the action of battery cell expansion force at different locations is determined.

[0138] Based on the strain information of each cell structure, temperature change data, and cell stack expansion coefficient, the expansion stress of the cell at different locations in the battery under test is determined.

[0139] Optionally, the matrixed data corresponding to the battery under test further includes an elastic matrix. The step of determining the expansion stress of the battery cells at different locations in the battery under test based on the strain information of each cell structure, temperature change data, and the cell stack expansion coefficient includes:

[0140] Based on temperature change data and the cell lamination expansion coefficient, the cell temperature strain information is determined.

[0141] Based on the cell temperature strain information, the strain information of each cell structure, and the elastic matrix corresponding to the battery under test, the expansion stress of the cell at different locations in the battery under test is determined.

[0142] The second determining module 430 is used to determine the structural stress exerted by the expansion stress of the battery cell on the structural component for any location of the battery cell in the battery to be tested, based on the expansion stress of the battery cell and the preset degree of freedom information of the structural component within a preset threshold distance from the battery cell.

[0143] Optionally, the preset degree-of-freedom information of the structural component includes the boundary contact force of the structural component, and the second determining module 430 is specifically used for:

[0144] For any cell in the battery under test, the structural stress exerted by the expansion stress of the cell on the structural component is determined based on the expansion stress of the cell and the contact force of the structural component boundary with the structural component within a preset threshold distance of the cell.

[0145] The judgment module 440 is used to determine the strain type of the structural component based on the structural stress of the structural component, wherein the strain type includes elastic strain and / or plastic strain.

[0146] The structural stress determination device 400 for battery structural components provided in this application embodiment, compared with the prior art, determines the expansion stress of the battery cell at different locations in the battery under test by using temperature change data, cell material parameters, location information, and cell expansion force. Based on the expansion stress of the battery cell and the preset degree of freedom information of the structural components within a preset threshold distance from the battery cell, the structural stress exerted by the expansion stress of the battery cell on the structural components is determined. This not only realizes the real-time monitoring of the expansion stress and structural stress of the battery cell, but also reduces the risk of structural component damage, improves the safety and sealing of the entire battery, and ensures the driving safety of new energy vehicles.

[0147] Please see Figure 5 , Figure 5 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 5 As shown, the electronic device 500 includes a processor 510, a memory 520, and a bus 530.

[0148] The memory 520 stores machine-readable instructions executable by the processor 510. When the electronic device 500 is running, the processor 510 and the memory 520 communicate via the bus 530. When the machine-readable instructions are executed by the processor 510, they can perform the operations described above. Figure 1 as well as Figure 2 The steps of the method for determining the structural stress of structural components in the battery in the method embodiment shown are described in detail in the method embodiment, and will not be repeated here.

[0149] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, can perform the above-described actions. Figure 1 as well as Figure 2 The steps of the method for determining the structural stress of structural components in the battery in the method embodiment shown are described in detail in the method embodiment, and will not be repeated here.

[0150] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0151] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the shown or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0152] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0153] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0154] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a processor-executable, non-volatile, computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0155] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The scope of protection of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the scope of the technology disclosed in this application. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for determining the structural stress of structural components in a battery, characterized in that, The method for determining the structural stress of structural components in the battery includes: The system acquires temperature change data of the battery under test during charging and discharging, cell expansion force of the battery under test at different temperatures, cell material parameters of the battery under test, and position information of each cell in the battery under test. Based on the temperature change data, the cell material parameters, the location information, and the cell expansion force, the expansion stress of the cell at different locations in the battery under test is determined. For any cell in the battery under test, the structural stress exerted by the expansion stress of the cell on the structural component is determined based on the expansion stress of the cell and the preset degree of freedom information of the structural component within a preset threshold distance from the cell. This includes: For any cell in the battery under test, the structural stress exerted by the expansion stress of the cell on the structural component is determined based on the expansion stress of the cell and the structural component boundary contact force of the structural component within a preset threshold distance from the cell; wherein, the preset degree of freedom information of the structural component includes the structural component boundary contact force. After determining the structural stress exerted on the structural component by the expansion stress of the battery cell, the method for determining the structural stress of the structural component in the battery further includes: Based on the structural stress of the structural component, the strain type of the structural component is determined, wherein the strain type includes elastic strain and / or plastic strain.

2. The method for determining the structural stress of structural components in a battery according to claim 1, characterized in that, The step of determining the expansion stress of the battery cell at different locations in the battery under test based on the temperature change data, the cell material parameters, the location information, and the cell expansion force includes: The battery to be tested is divided into units and nodes according to a grid, and the corresponding units and nodes of the battery to be tested are determined. The battery to be tested is divided into matrices according to the finite element method to determine the matrix data corresponding to the battery to be tested. Based on the preset cell expansion force, the stiffness matrix in the cell material parameters, and the position information, the displacement information at each node of the cell is determined; Based on the displacement information, temperature change data, and material parameters of the battery cell at each node, the expansion stress of the battery cell at different locations in the battery under test is determined.

3. The method for determining the structural stress of structural components in a battery according to claim 2, characterized in that, The cell material parameters include the cell stack expansion coefficient. The determination of the expansion stress of the cell at different locations in the battery under test, based on displacement information, temperature change data, and the cell material parameters at each node of the cell, includes: Based on the displacement information at each node of the battery cell, the strain information of the battery cell structure under the action of battery cell expansion force at different locations is determined; Based on the strain information of each cell structure, temperature change data, and cell stack expansion coefficient, the expansion stress of the cell at different locations in the battery under test is determined.

4. The method for determining the structural stress of structural components in a battery according to claim 3, characterized in that, The matrixed data corresponding to the battery to be tested includes the geometric structure matrix of the cell. The determination of the cell structure strain information at different locations under the action of cell expansion force, based on the displacement information at each node of the cell, includes: Based on the displacement information at each node of the battery cell and the geometric structure matrix, the strain information of the battery cell structure under the action of battery cell expansion force at different locations is determined.

5. The method for determining the structural stress of structural components in a battery according to claim 3, characterized in that, The matrixed data corresponding to the battery under test also includes an elastic matrix. The determination of the expansion stress of the battery cells at different locations within the battery under test, based on the strain information of each cell structure, temperature change data, and the cell stack expansion coefficient, includes: Based on temperature change data and the cell lamination expansion coefficient, the cell temperature strain information of the battery cell is determined; Based on the cell temperature strain information, the strain information of each cell structure, and the elastic matrix corresponding to the battery under test, the expansion stress of the cell at different locations in the battery under test is determined.

6. A device for determining the structural stress of structural components in a battery, characterized in that, The structural stress determination device for structural components in the battery includes: The acquisition module is used to acquire temperature change data of the battery under test during the charging and discharging process, cell expansion force of the battery under test at different temperatures, cell material parameters of the battery under test, and position information of each cell in the battery under test. The first determining module is used to determine the expansion stress of the battery cell at different locations in the battery under test based on the temperature change data, the battery cell material parameters, the position information, and the battery cell expansion force. The second determining module is used to determine the structural stress exerted by the expansion stress of the battery cell on the structural component at any location in the battery to be tested, based on the expansion stress of the battery cell and the preset degree of freedom information of the structural component within a preset threshold distance from the battery cell. Specifically, the second determining module is used to: For any cell in the battery under test, the structural stress exerted by the expansion stress of the cell on the structural component is determined based on the expansion stress of the cell and the structural component boundary contact force of the structural component within a preset threshold distance from the cell; wherein, the preset degree of freedom information of the structural component includes the structural component boundary contact force. The structural stress determination device for structural components in a battery also includes a judgment module, which is used for: Based on the structural stress of the structural component, the strain type of the structural component is determined, wherein the strain type includes elastic strain and / or plastic strain.

7. An electronic device, characterized in that, include: The device includes a processor, a memory, and a bus. The memory stores machine-readable instructions executable by the processor. When the electronic device is running, the processor communicates with the memory via the bus. The machine-readable instructions are executed by the processor to perform the steps of the method for determining the structural stress of structural components in a battery as described in any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, performs the steps of the method for determining the structural stress of structural components in a battery as described in any one of claims 1 to 5.

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