Battery pack thermal runaway simulation method, device and setting and storage medium
The electrothermal and mechanical characteristics of the battery cell are obtained through simulation methods, and the risk of thermal runaway in the collision of the whole vehicle is analyzed, which solves the problem of thermal runaway in the battery pack, and realizes the lean design and cost saving of the battery pack.
Patent Information
- Application Number
- CN202411167819.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-23
- Publication Date
- 2024-12-17
AI Technical Summary
The prior art has failed to effectively analyze and solve the thermal runaway problem caused by mechanical abuse during the collision of the new energy vehicle battery pack during the vehicle, especially the mechanical characteristics of the battery cell have not been considered, which makes the risk of thermal runaway difficult to evaluate and avoid.
The uniform electrothermal and mechanical characteristics of the battery cell are obtained through simulation methods, a volume unit model is established, the temperature and strain relationship of the battery cell is calculated, and whether the battery pack has thermal runaway occurs, and the accuracy of the simulation results is verified through extrusion simulation tests.
It effectively avoids the risk of thermal runaway caused by deformation of the battery pack, realizes lean design of the battery pack, shortens the development cycle and saves costs.
Smart Images
Figure CN119150525A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of simulation technology, and in particular to a battery pack thermal runaway simulation method, device, setting and storage medium. Background Art
[0002] New energy vehicles have gradually become the most promising vehicles with their low noise, environmental protection, and energy saving features, and have been valued and loved by the public. However, the fire problem of new energy vehicle battery packs is still a concern. Lithium-ion batteries are high-performance, rechargeable and recyclable batteries. When subjected to external forces such as squeezing, impact, and puncture, they are prone to short circuit and fire, generating a large amount of heat and spreading rapidly, posing a huge safety hazard to electric vehicles. There are three types of thermal runaway: electrical abuse, thermal abuse, and mechanical abuse. This article mainly focuses on the thermal runaway problem caused by squeezing (mechanical abuse) of the battery pack in the side column collision condition of the whole vehicle. However, mechanical abuse often causes the battery cell to short-circuit (electrical abuse), thereby releasing a large amount of heat, and then the heat will quickly spread (thermal abuse), so mechanical abuse is very complicated.
[0003] Most existing studies focus on the electrothermal characteristics of battery thermal runaway, without considering some mechanical properties of the battery cell. Moreover, most of them are cell-level simulations, without considering the thermal runaway problem of the battery pack during the vehicle-level collision.
[0004] Therefore, how to analyze the risk of thermal runaway caused by battery pack deformation and avoid thermal runaway is a technical problem that needs to be solved urgently. Summary of the invention
[0005] The main purpose of the present invention is to provide a battery pack thermal runaway simulation method, device, setting and storage medium, which can effectively avoid the risk of thermal runaway caused by battery pack deformation, realize lean design of battery pack, shorten the development cycle and save costs.
[0006] In a first aspect, the present application provides a method for simulating thermal runaway of a battery pack, wherein the method comprises the steps of:
[0007] Determine a first functional relationship between temperature and strain of electrical abuse based on the homogenized electrothermal characteristics of the battery cell obtained by simulation, and determine a second functional relationship between temperature and strain of thermal abuse through a temperature parameter in the first functional relationship;
[0008] Based on the homogenized mechanical properties of the battery cell obtained through simulation, the third function relationship between stress and strain of the battery cell is obtained;
[0009] The maximum temperature generated by the battery cell is calculated through the second functional relationship and the third functional relationship, and the maximum temperature is used to determine whether thermal runaway occurs in the battery pack.
[0010] In combination with the first aspect above, as an optional implementation method, a first-order equivalent circuit model is established based on the volume unit model RVE, and a homogenized electrothermal simulation is performed on the battery cell to obtain a functional relationship between the strain and temperature of the battery cell;
[0011] Calculating the heating power of the battery cell according to the functional relationship between the strain and temperature of the battery cell;
[0012] Based on the contact area of the positive and negative electrodes of the battery cell and the thickness of the separator, the resistivity is calculated, and combined with the calculated heating power, a functional relationship between the contact area of the battery cell and the heating power is determined;
[0013] According to the functional relationship between the cell contact area and the strain and the functional relationship between the cell contact surface and the heat generation power obtained in the cell-level collision simulation, the functional relationship between the heat generation power and the strain of the electrical abuse is determined;
[0014] The heat generation power is converted into a temperature parameter to determine a first function relationship of temperature and strain of the electrical abuse.
[0015] In combination with the first aspect above, as an optional implementation manner, the actual strain tensor of the battery cell is obtained through the functional relationship between the stress and strain of the battery cell;
[0016] Calculating the maximum temperature generated by the battery cell based on the functional relationship between the temperature and strain of the thermal abuse and the strain tensor;
[0017] According to the formula: Q total =Q sei +Q ne +Q pe +Q pvdf +Q ele =∑ j H j W j R j , calculate the maximum temperature generated by the battery cell, where Q sei is the heat generated by the decomposition reaction of the SEI film, Q ne is the heat generated by the reaction between the negative electrode and the electrolyte, Q pe is the heat generated by the reaction between the positive electrode and the electrolyte, Q pvdf is the heat generated by the decomposition reaction of the binder, Q ele The heat generated by the decomposition reaction of the electrolyte.
[0018] In combination with the first aspect above, as an optional implementation method, a volume unit model RVE is established, and the RVE model is used to perform a homogenized mechanical simulation on the battery cell to obtain the functional relationship between the stress and strain of the battery cell material.
[0019] In combination with the first aspect above, as an optional implementation manner, the properties of the battery core material are input into the RVE model, and the RVE model is compressed and sheared to obtain the anisotropic material properties of the battery core material.
[0020] In combination with the first aspect above, as an optional implementation, if the maximum temperature is greater than or equal to a set threshold, it is determined that thermal runaway occurs in the battery pack;
[0021] If the maximum temperature is less than the set threshold, it is determined that thermal runaway does not occur in the battery pack.
[0022] In combination with the first aspect above, as an optional implementation method, an extrusion simulation test is performed on the battery cell to output the maximum temperature of the battery cell after being extruded and deformed;
[0023] The maximum temperature is compared with the temperature value actually measured during collision of the battery cell to verify whether the simulation result is accurate.
[0024] In a second aspect, the present application provides a battery pack thermal runaway simulation device, the device comprising:
[0025] A determination module, which is used to determine a first functional relationship between temperature and strain of electrical abuse based on the homogenized electrothermal characteristics of the battery cell obtained by simulation, and determine a second functional relationship between temperature and strain of thermal abuse through a temperature parameter in the first functional relationship;
[0026] An acquisition module, which is used to acquire a third functional relationship between stress and strain of the battery cell based on the homogenized mechanical properties of the battery cell acquired through simulation;
[0027] A processing module is used to calculate the maximum temperature generated by the battery cell through the second functional relationship and the third functional relationship, and to determine whether thermal runaway occurs in the battery pack through the maximum temperature.
[0028] In a third aspect, the present application further provides an electronic device, comprising: a processor; a memory, wherein the memory stores computer-readable instructions, and when the computer-readable instructions are executed by the processor, the method described in any one of the first aspects is implemented.
[0029] In a fourth aspect, the present application further provides a computer-readable storage medium storing computer program instructions, which, when executed by a computer, enables the computer to execute any of the methods described in the first aspect.
[0030] The present application provides a method, device, setting and storage medium for simulating thermal runaway of a battery pack, wherein the method includes the following steps: determining a first functional relationship between temperature and strain of electrical abuse based on the homogenized electrothermal characteristics of the battery cell obtained through simulation, and determining a second functional relationship between temperature and strain of thermal abuse through the temperature parameter in the first functional relationship; obtaining a third functional relationship between stress and strain of the battery cell based on the homogenized mechanical characteristics of the battery cell obtained through simulation; calculating the maximum temperature generated by the battery cell through the second functional relationship and the third functional relationship, and judging whether thermal runaway occurs in the battery pack through the maximum temperature. The present application can effectively avoid the risk of thermal runaway caused by deformation of the battery pack, realize lean design of the battery pack, and shorten the development cycle and save costs.
[0031] It is to be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.
[0033] Figure 1 A flow chart of a battery pack thermal runaway simulation method provided in an embodiment of the present application;
[0034] Figure 2 A schematic diagram of a battery pack thermal runaway simulation device provided in an embodiment of the present application;
[0035] Figure 3 A schematic diagram of a process for calculating the maximum temperature of a battery pack provided in an embodiment of the present application;
[0036] Figure 4 A schematic diagram of an electronic device provided in an embodiment of the present application;
[0037] Figure 5 A schematic diagram of a computer-readable program medium provided in an embodiment of the present application. DETAILED DESCRIPTION
[0038] Here, exemplary embodiments will be described in detail, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are merely examples of devices and methods consistent with some aspects of the present invention as detailed in the appended claims.
[0039] Furthermore, the drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale. Some of the blocks shown in the drawings are functional entities and do not necessarily correspond to physically or logically separate entities.
[0040] The embodiments of the present application provide a battery pack thermal runaway simulation method, device, setting and storage medium, which can effectively avoid the risk of thermal runaway caused by battery pack deformation, realize lean design of the battery pack, and at the same time shorten the development cycle and save costs.
[0041] In order to achieve the above technical effects, the general idea of this application is as follows:
[0042] A battery pack thermal runaway simulation method, the method comprising the steps of:
[0043] S101: Determine a first functional relationship between temperature and strain of electrical abuse based on homogenized electrothermal characteristics of the battery cell obtained through simulation, and determine a second functional relationship between temperature and strain of thermal abuse through a temperature parameter in the first functional relationship.
[0044] S102: Based on the homogenized mechanical properties of the battery cell obtained through simulation, a third functional relationship between stress and strain of the battery cell is obtained.
[0045] S103: Calculate the maximum temperature generated by the battery cell through the second functional relationship and the third functional relationship, and determine whether thermal runaway occurs in the battery pack through the maximum temperature.
[0046] The embodiments of the present application are further described in detail below in conjunction with the accompanying drawings.
[0047] Reference Figure 1 , Figure 1 FIG. 1 is a flow chart of a battery pack thermal runaway simulation method provided by the present invention. Figure 1 As shown, the method comprises the steps of:
[0048] Step S101: Based on the homogenized electrothermal characteristics of the battery cell obtained by simulation, determine a first functional relationship between temperature and strain of electrical abuse, and determine a second functional relationship between temperature and strain of thermal abuse through a temperature parameter in the first functional relationship.
[0049] Specifically, based on the volume unit model RVE, a first-order equivalent circuit model is established, and a homogenized electrothermal simulation is performed on the battery cell to obtain the functional relationship between the strain and temperature of the battery cell;
[0050] Calculating the heating power of the battery cell according to the functional relationship between the strain and temperature of the battery cell;
[0051] Based on the contact area of the positive and negative electrodes of the battery cell and the thickness of the separator, the resistivity is calculated, and combined with the calculated heating power, a functional relationship between the contact area of the battery cell and the heating power is determined;
[0052] According to the functional relationship between the cell contact area and the strain and the functional relationship between the cell contact surface and the heat generation power obtained in the cell-level collision simulation, the functional relationship between the heat generation power and the strain of the electrical abuse is determined;
[0053] The heat generation power is converted into a temperature parameter to determine a first function relationship of temperature and strain of the electrical abuse.
[0054] Using the temperature parameter in the first function, substitute into the formula: Q total =Q sei +Q ne +Q pe +Q pvdf +Q ele =∑ j H j W j R j , determine the second functional relationship between the temperature and strain of thermal abuse. It can be understood that the expression of electrical abuse and thermal abuse is T=ax^3+bx^2+cx+d, where x is strain, T is temperature, and abcd are all constants.
[0055] For ease of understanding, an example is given to establish a representative volume element (RVE), which can accurately characterize the behavior of macroscopic objects while taking into account the microscopic properties of the material. The basic material parameters of the RVE model are obtained based on experiments on the specific materials of the battery cell, and the model is layered according to the positive electrode, negative electrode, and separator.
[0056] Obtain the homogenized electrothermal properties of the microscopic model: Choose to use the first-order RC equivalent circuit model (to simulate electrical abuse, that is, the process of short circuit causing heating, and to obtain the relationship between strain and heating power). The first-order RC equivalent circuit model is based on the RVE model, that is, it is part of the RVE model. Since the capacitor in the equivalent circuit has less energy storage, the heating effect on the overall circuit model can be ignored, so the heating power of the battery can be expressed as follows: P≈i×(U oc -U L ), where U oc is the open circuit voltage of the battery, U L is the terminal voltage, and i is the discharge current.
[0057] After confirming the various parameters of the battery, the resistivity of the battery electrode can be calculated by the electrical conductivity of its material. Since the resistance of the positive and negative current collectors is much smaller than that of the active material, it can be ignored. The resistivity of the diaphragm is set to 10^8Ω·m when there is no short circuit. When a short circuit occurs, the resistivity changes with the contact area between the positive and negative electrodes, ρ=RA / H. Where ρ is the resistivity, H is the thickness of the diaphragm, R is the ohmic resistance, and A is the contact area between the positive and negative electrodes. Combining the formula for heat generation power and Ohm's law, the relationship between contact area and heat generation power can be obtained (P=IU=I 2 R, Transform the formula ), and then according to the relationship between the contact area of the positive and negative electrodes of the battery and the strain obtained in the cell-level collision simulation, the relationship between the strain and the heat generation power is obtained, and the heat generation power is converted into a temperature parameter to determine the first functional relationship between the temperature and the strain of electrical abuse. The heat and temperature formula is Q release = cm (t0-t), where Q release represents the heat released by the object, c represents the specific heat capacity of the substance, m represents the mass of the object, t0 represents the initial temperature of the object, and t represents the final temperature of the object. It should be noted that when the strain is small, the short circuit does not occur, so the battery heating can be ignored. The critical strain for short circuit is obtained based on the deformation of the battery when it is short-circuited in the previous experimental data. The deformation is used as a forced displacement and is calculated in the collision simulation to obtain the strain corresponding to the deformation.
[0058] Step S102: Based on the homogenized mechanical properties of the battery cell obtained through simulation, a third functional relationship between stress and strain of the battery cell is obtained.
[0059] Specifically, a volume unit model RVE is established, and the RVE model is used to perform a homogenized mechanical simulation on the battery cell to obtain the functional relationship between the stress and strain of the battery cell material. The battery cell material properties are input into the RVE model, and the RVE model is compressed and sheared to obtain the anisotropic material properties of the battery cell material.
[0060] Specifically, a representative volume element (RVE) is established, which can accurately characterize the behavior of macroscopic objects while taking into account the microscopic properties of the material. The basic material parameters of the RVE model are obtained according to experiments on the specific materials of the battery cell, and the model is layered according to the positive electrode, negative electrode, and separator. The main purpose of constructing the RVE model is to obtain the mechanical properties (stress-strain curve) and electrothermal properties (strain and temperature change curve) of the battery cell material.
[0061] Obtaining the homogenized mechanical properties of the microscopic model: Four different compression and shear forces need to be applied to the RVE model to obtain the anisotropic material properties of the cell material. The material stress-strain curves obtained under the four loading conditions can be directly used for the material properties of the battery pack in the macroscopic vehicle collision simulation model. It should be explained that the material properties refer to the four stress-strain curves.
[0062] It needs to be explained that homogenization can be understood as the entire battery cell is made of the same material. Mechanical properties can be understood as several stress-strain curves, and electrothermal properties are the relationship between strain and temperature. That is, mechanical properties are stress-strain curves, and electrothermal characteristics are the curve relationship between strain and temperature.
[0063] Step S103: Calculate the maximum temperature generated by the battery cell through the second functional relationship and the third functional relationship, and determine whether thermal runaway occurs in the battery pack through the maximum temperature.
[0064] Specifically, the actual strain tensor of the battery cell is obtained through the functional relationship between the stress and strain of the battery cell; the maximum temperature generated by the battery cell is calculated according to the functional relationship between the temperature and strain of the thermal abuse and the strain tensor; wherein, according to the formula: Q total =Q sei +Q ne +Q pe +Q pvdf +Q ele =∑ j H j W j R j , calculate the maximum temperature generated by the battery cell, where Q sei is the heat generated by the decomposition reaction of the SEI film, Q ne is the heat generated by the reaction between the negative electrode and the electrolyte, Q pe is the heat generated by the reaction between the positive electrode and the electrolyte, Q pvdf is the heat generated by the decomposition reaction of the binder, Q ele The heat generated by the decomposition reaction of the electrolyte.
[0065] After obtaining the temperature rise curve caused by electrical abuse of the microscopic simulation model, thermal abuse calculation can be performed. The main heat of thermal abuse comes from the decomposition of the solid electrolyte interface (SEI), the decomposition of the electrolyte, the decomposition of the binder and the diaphragm, the reaction between the positive electrode and the electrolyte, and the reaction between the negative electrode and the electrolyte. It can be expressed by the formula:
[0066] Q total =Q sei +Q ne +Q pe +Qpvdf +Q ele =Σ j H j W j R j
[0067] In the formula, Q total is the total heat generated by the thermal runaway side reaction, Q sei , Q ne , Q pe , Q pvdf and Q ele are the heat generated by each side reaction, in W·m -3 In addition, H j is the heat produced by the reaction per kilogram of substance, in J·kg -1 ,W j is the carbon content per unit volume, in kg·m -3 , and R j Represents the reaction rate in s -1 Substituting the temperature parameter in the first functional relationship into the formula, the second functional relationship between the temperature and strain of thermal abuse is obtained.
[0068] Among them, the heat generated by the decomposition reaction of the SEI film is: Q sei =H sei W sei R sei ,
[0069] Heat generated by the reaction between the negative electrode and the electrolyte: Q ne =H ne W ne R ne ,
[0070]
[0071] Heat generated by the reaction between the positive electrode and the electrolyte: Q pe =H pe W pe R pe ,
[0072]
[0073] Heat generated by the decomposition reaction of the binder: Q pvdf =H pvdf W pvdf R pvdf ,
[0074] Heat generated by the decomposition reaction of the electrolyte: Q ele =H ele W ele Rele ,
[0075] Among them, A x and E x are the pre-factors and activation energies in each reaction, in units of s -1 and J.mol -1 ;m x is the reaction order of each reactant material, C x The dimensionless number of each reactant material, R is the molar gas constant, usually taken as 8.314 J·mol -1 ·K -1 , T is the temperature change, the unit is K. In addition, in the reaction between the positive electrode and the electrolyte, m1 and m2 are the reaction orders of the reaction between the positive electrode and the electrolyte, and b is the dimensionless number of the positive electrode material.
[0076] It can be understood that the second functional relationship and the third functional relationship obtained above can be used to calculate the temperature when the stress is obtained. In one embodiment, if the maximum temperature is greater than or equal to a set threshold, it is determined that the battery pack has thermal runaway;
[0077] If the maximum temperature is less than the set threshold, it is determined that thermal runaway does not occur in the battery pack.
[0078] In one embodiment, an extrusion simulation test is performed on the battery cell to output the maximum temperature of the battery cell after being extruded and deformed; the maximum temperature is compared with the temperature value generated by the actual measured collision of the battery cell to verify whether the simulation result is accurate.
[0079] Specifically, in order to further ensure the accuracy of temperature changes in vehicle collision simulation, simulation verification at the cell level is necessary. The cell material needs to use the obtained material curve (stress-strain curve). The cell will be forced to be displaced and squeezed with a rigid column. The strain output from the simulation is combined with the relationship between the strain and temperature of the electrical abuse, and the maximum temperature of the cell after being squeezed and deformed is output. Finally, the simulation results are compared with the cell extrusion test results to ensure the accuracy of the simulation results.
[0080] Optionally, the aligned battery cell simulation model is placed into the vehicle model for vehicle collision simulation. The vehicle will hit a rigid column with a diameter of 254 mm from the side at a speed of 32 km / h. A collision angle of about 75° should be formed between the vertical plane of the vehicle collision velocity vector and the longitudinal centerline of the vehicle.
[0081] Reference Figure 2 , Figure 2 FIG. 1 is a schematic diagram of a battery pack thermal runaway simulation device provided by the present invention, such as Figure 2 As shown, the device comprises:
[0082] Determination module 201: It is used to determine the first functional relationship between the temperature and strain of electrical abuse based on the homogenized electrothermal characteristics of the battery cell obtained by simulation, and determine the second functional relationship between the temperature and strain of thermal abuse through the temperature parameter in the first functional relationship.
[0083] The acquisition module 202 is used to acquire the third functional relationship between the stress and strain of the battery cell based on the homogenized mechanical properties of the battery cell acquired through simulation.
[0084] Processing module 203: It is used to calculate the maximum temperature generated by the battery cell through the second functional relationship and the third functional relationship, and determine whether thermal runaway occurs in the battery pack through the maximum temperature.
[0085] Furthermore, in a possible implementation, the determination module is further used to establish a first-order equivalent circuit model based on the volume unit model RVE, and perform a homogenized electrothermal simulation on the battery cell to obtain a functional relationship between the strain and temperature of the battery cell;
[0086] Calculating the heating power of the battery cell according to the functional relationship between the strain and temperature of the battery cell;
[0087] Based on the contact area of the positive and negative electrodes of the battery cell and the thickness of the separator, the resistivity is calculated, and combined with the calculated heating power, a functional relationship between the contact area of the battery cell and the heating power is determined;
[0088] According to the functional relationship between the cell contact area and the strain and the functional relationship between the cell contact surface and the heat generation power obtained in the cell-level collision simulation, the functional relationship between the heat generation power and the strain of the electrical abuse is determined;
[0089] The heat generation power is converted into a temperature parameter to determine a first function relationship of temperature and strain of the electrical abuse.
[0090] Furthermore, in a possible implementation manner, the processing module is further used to obtain an actual strain tensor of the battery cell through a functional relationship between stress and strain of the battery cell;
[0091] Calculating the maximum temperature generated by the battery cell based on the functional relationship between the temperature and strain of the thermal abuse and the strain tensor;
[0092] According to the formula: Q total =Q sei +Q ne +Q pe +Q pvdf +Q ele =∑ j H j W j R j , calculate the maximum temperature generated by the battery cell, where Q seiis the heat generated by the decomposition reaction of the SEI film, Q ne is the heat generated by the reaction between the negative electrode and the electrolyte, Q pe is the heat generated by the reaction between the positive electrode and the electrolyte, Q pvdf is the heat generated by the decomposition reaction of the binder, Q ele The heat generated by the decomposition reaction of the electrolyte.
[0093] Furthermore, in a possible implementation, the acquisition module is also used to establish a volume unit model RVE, and use the RVE model to perform a homogenized mechanical simulation on the battery cell to obtain a functional relationship between stress and strain of the battery cell material.
[0094] Furthermore, in a possible implementation manner, the acquisition module is also used to input the properties of the battery core material into the RVE model, and compress and shear the RVE model to obtain the anisotropic material properties of the battery core material.
[0095] Furthermore, in a possible implementation manner, the processing module is further configured to determine that thermal runaway occurs in the battery pack if the maximum temperature is greater than or equal to a set threshold;
[0096] If the maximum temperature is less than the set threshold, it is determined that thermal runaway does not occur in the battery pack.
[0097] Furthermore, in a possible implementation manner, the processing module is further used to perform an extrusion simulation test on the battery cell to output a maximum temperature of the battery cell after being extruded and deformed;
[0098] The maximum temperature is compared with the temperature value actually measured during collision of the battery cell to verify whether the simulation result is accurate.
[0099] Reference Figure 3 , Figure 3 FIG. 1 is a schematic diagram of a process flow for calculating the maximum temperature of a battery pack provided by the present invention. Figure 3 As shown:
[0100] The entire process is divided into microscale and macroscale, where the microscale is further divided into electrothermal simulation and mechanical simulation, to obtain the homogenized electrothermal and mechanical properties of the battery cell respectively. The electrothermal properties are used to simulate the electrical abuse process and calculate the relationship between the heating power and strain, and the mechanical properties are used to calculate the macroscopic battery cell extrusion simulation. Subsequently, the heat release caused by thermal abuse is calculated based on the heat obtained from the electrical abuse (where strain is a variable parameter, so the heat here is not a value, but a functional relationship with strain as a parameter). The final output is the relationship between the heat and strain generated by the full set of processes of mechanical abuse-->electrical abuse-->thermal abuse. In terms of the macroscale, extrusion simulation is performed based on the mechanical properties obtained at the microscale, and after benchmarking with the test, the whole vehicle collision simulation is performed to obtain the maximum strain of the battery cell. Then, based on the functional relationship and maximum strain mentioned above, the highest temperature generated by the battery cell during the whole vehicle collision process can be calculated.
[0101] What needs to be explained is the functional relationship between temperature and stress caused by output electrical abuse and thermal abuse, that is, the explanation of the electrothermal characteristics of the homogenized battery cell. Homogenization means that the entire battery cell is made of the same material, the mechanical property is the stress-strain curve, and the electrothermal characteristic is the curve relationship between strain and temperature.
[0102] It is understandable that this application analyzes the risk of thermal runaway caused by battery pack deformation in the simulation of the vehicle side column collision, taking into account the electrical abuse caused by the mechanical abuse of the battery pack, which in turn triggers the full process of heat release caused by thermal abuse. In vehicle development projects, major risks in battery pack development can be identified at the simulation stage, and collision simulation engineers can intervene in the early development of battery packs earlier, while also achieving lean design of battery packs and improving the one-time pass rate of vehicle collision tests.
[0103] Refer to the following Figure 4 An electronic device 400 according to this embodiment of the present invention will be described. Figure 4 The electronic device 400 shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present invention.
[0104] like Figure 4 As shown, the electronic device 400 is in the form of a general computing device. The components of the electronic device 400 may include but are not limited to: at least one processing unit 410, at least one storage unit 420, and a bus 430 connecting different system components (including the storage unit 420 and the processing unit 410).
[0105] The storage unit stores program codes, which can be executed by the processing unit 410, so that the processing unit 410 executes the steps according to various exemplary embodiments of the present invention described in the above “Embodiment Method” section of this specification.
[0106] The storage unit 420 may include a readable medium in the form of a volatile storage unit, such as a random access memory unit (RAM) 421 and / or a cache memory unit 422 , and may further include a read-only memory unit (ROM) 423 .
[0107] The storage unit 420 may also include a program / utility 424 having a set (at least one) of program modules 425, such program modules 425 including but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment.
[0108] Bus 430 may represent one or more of several types of bus structures, including a memory unit bus or memory unit controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus architectures.
[0109] The electronic device 400 may also communicate with one or more external devices (e.g., keyboards, pointing devices, Bluetooth devices, etc.), may also communicate with one or more devices that enable a user to interact with the electronic device 400, and / or communicate with any device that enables the electronic device 400 to communicate with one or more other computing devices (e.g., routers, modems, etc.). Such communication may be performed via an input / output (I / O) interface 450. Furthermore, the electronic device 400 may also communicate with one or more networks (e.g., local area networks (LANs), wide area networks (WANs), and / or public networks, such as the Internet) via a network adapter 460. As shown, the network adapter 460 communicates with other modules of the electronic device 400 via a bus 430. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with the electronic device 400, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems, etc.
[0110] Through the description of the above implementation, it is easy for those skilled in the art to understand that the example implementation described here can be implemented by software, or by software combined with necessary hardware. Therefore, the technical solution according to the implementation of the present disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, including several instructions to enable a computing device (which can be a personal computer, a server, a terminal device, or a network device, etc.) to execute the method according to the implementation of the present disclosure.
[0111] According to the solution of the present disclosure, a computer-readable storage medium is also provided, on which a program product capable of implementing the above method of the present specification is stored. In some possible implementations, various aspects of the present invention can also be implemented in the form of a program product, which includes a program code, and when the program product is run on a terminal device, the program code is used to enable the terminal device to execute the steps according to various exemplary implementations of the present invention described in the above "Exemplary Method" section of the present specification.
[0112] refer to Figure 5 As shown, a program product 500 for implementing the above method according to an embodiment of the present invention is described, which can adopt a portable compact disk read-only memory (CD-ROM) and include program code, and can be run on a terminal device, such as a personal computer. However, the program product of the present invention is not limited thereto. In this document, a readable storage medium can be any tangible medium containing or storing a program, which can be used by or in combination with an instruction execution system, an apparatus or a device.
[0113] The program product may use any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. The readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.
[0114] Computer readable signal media may include data signals propagated in baseband or as part of a carrier wave, in which readable program code is carried. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. Readable signal media may also be any readable medium other than a readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device.
[0115] The program code embodied on the readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wired, optical cable, RF, etc., or any suitable combination of the foregoing.
[0116] Program code for performing the operations of the present invention may be written in any combination of one or more programming languages, including object-oriented programming languages such as Java, C++, etc., and conventional procedural programming languages such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a separate software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server. In cases involving a remote computing device, the remote computing device may be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computing device (e.g., through the Internet using an Internet service provider).
[0117] In addition, the above-mentioned figures are only schematic illustrations of the processes included in the method according to an exemplary embodiment of the present invention, and are not intended to be limiting. It is easy to understand that the processes shown in the above-mentioned figures do not indicate or limit the time sequence of these processes. In addition, it is also easy to understand that these processes can be performed synchronously or asynchronously, for example, in multiple modules.
[0118] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.
[0119] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems) and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the process in the flowchart. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.
Claims
1. A battery pack thermal runaway simulation method, characterized in that: include: Determine a first functional relationship between temperature and strain of electrical abuse based on the homogenized electrothermal characteristics of the battery cell obtained by simulation, and determine a second functional relationship between temperature and strain of thermal abuse through a temperature parameter in the first functional relationship; Based on the homogenized mechanical properties of the battery cell obtained through simulation, the third function relationship between stress and strain of the battery cell is obtained; The maximum temperature generated by the battery cell is calculated by using the second functional relationship and the third functional relationship, and whether thermal runaway occurs in the battery pack is determined by using the maximum temperature.
2. The method according to claim 1, characterized in that The determining of a first functional relationship between strain and temperature of electrical abuse based on homogenized electrothermal characteristics of the battery cell obtained by simulation includes: Based on the volume unit model RVE, a first-order equivalent circuit model is established, and a homogenized electrothermal simulation is performed on the battery cell to obtain the functional relationship between the strain and temperature of the battery cell; Calculating the heating power of the battery cell according to the functional relationship between the strain and temperature of the battery cell; Based on the contact area of the positive and negative electrodes of the battery cell and the thickness of the separator, the resistivity is calculated, and combined with the calculated heating power, a functional relationship between the contact area of the battery cell and the heating power is determined; According to the functional relationship between the cell contact area and the strain and the functional relationship between the cell contact surface and the heat generation power obtained in the cell-level collision simulation, the functional relationship between the heat generation power and the strain of the electrical abuse is determined; The heat generation power is converted into a temperature parameter to determine a first function relationship of temperature and strain of the electrical abuse.
3. The method according to claim 1, characterized in that The calculating the maximum temperature generated by the battery cell by using the second functional relationship and the third functional relationship includes: Obtaining the actual strain tensor of the battery cell through the functional relationship between the stress and strain of the battery cell; Calculating the maximum temperature generated by the battery cell based on the functional relationship between the temperature and strain of the thermal abuse and the strain tensor; According to the formula: Q total =Q sei +Q ne +Q pe +Q pvdf +Q ele =∑ j H j W j R j , calculate the maximum temperature generated by the battery cell, where Q sei is the heat generated by the decomposition reaction of the SEI film, Q ne is the heat generated by the reaction between the negative electrode and the electrolyte, Q pe is the heat generated by the reaction between the positive electrode and the electrolyte, Q pvdf is the heat generated by the decomposition reaction of the binder, Q ele The heat generated by the decomposition reaction of the electrolyte.
4. The method according to claim 1, characterized in that: The homogenized mechanical properties of the battery cell obtained based on simulation include: A volume unit model RVE is established, and the RVE model is used to perform a uniform mechanical simulation on the battery cell to obtain the functional relationship between the stress and strain of the battery cell material.
5. The method according to claim 4, characterized in that Also includes: The cell material properties are input into the RVE model, and the RVE model is compressed and sheared to obtain the anisotropic material properties of the cell material.
6. The method according to claim 1, characterized in that The determining whether thermal runaway occurs in the battery pack according to the maximum temperature includes: If the maximum temperature is greater than or equal to a set threshold, it is determined that thermal runaway occurs in the battery pack; If the maximum temperature is less than the set threshold, it is determined that thermal runaway does not occur in the battery pack.
7. The method according to claim 1, characterized in that Also includes: Conduct an extrusion simulation test on the battery cell to output the maximum temperature of the battery cell after being extruded and deformed; The maximum temperature value is compared with the temperature value generated by the actual measured collision of the battery cell to verify whether the simulation result is accurate.
8. A battery pack thermal runaway simulation device, characterized in that: include: A determination module, which is used to determine a first functional relationship between temperature and strain of electrical abuse based on the homogenized electrothermal characteristics of the battery cell obtained by simulation, and determine a second functional relationship between temperature and strain of thermal abuse through a temperature parameter in the first functional relationship; An acquisition module, which is used to acquire a third functional relationship between stress and strain of the battery cell based on the homogenized mechanical properties of the battery cell acquired through simulation; A processing module is used to calculate the maximum temperature generated by the battery cell through the second functional relationship and the third functional relationship, and to determine whether thermal runaway occurs in the battery pack through the maximum temperature.
9. An electronic device, characterized in that: The electronic device comprises: processor; A memory having computer-readable instructions stored thereon, wherein when the computer-readable instructions are executed by the processor, the method according to any one of claims 1 to 7 is implemented.
10. A computer-readable storage medium, characterized in that: The computer program instructions are stored therein, and when the computer program instructions are executed by a computer, the computer is caused to execute the method according to any one of claims 1 to 7.