Battery thermal runaway simulation method, device and equipment and readable storage medium

Abstract

The invention discloses a battery thermal runaway simulation method, device and equipment and a readable storage medium, and the method comprises the steps: generating a target cell splitting model based on a cell original digital model and a grid size of a target cell, and splitting a target cell roll core in the cell splitting model into a plurality of splitting modules; constructing a system simulation model according to the current simulated system thermal insulation design digital model, the target cell splitting model and thermophysical parameters set according to the material of each cell part; inputting heat to the target cell by loading an external heat source, and detecting the module temperature of each split module in the target cell split model and the average temperature of the split modules; according to the module temperature of each split module and the average temperature of the split modules, self-generated heat compensation and eruption compensation are conducted on each split module; and detecting the overall average temperature of the target cell, and determining a thermal runaway judgment result of the target cell. The thermal runaway dynamic process is comprehensively simulated by splitting the battery cell module and comprehensively simulating the heat source.

Description

Technical Field

[0001] The present application relates to the field of battery testing, and more specifically, to a battery thermal runaway simulation method, device, equipment and readable storage medium. Background Art

[0002] In the field of battery thermal runaway protection design, in order to evaluate the effectiveness and rationality of the battery cell thermal insulation design scheme, the existing technology mainly relies on thermal simulation technology. This technology simulates the thermal behavior of the battery under different working conditions by computer, and can predict key parameters such as temperature distribution and thermal runaway propagation speed, providing an important reference for designers. Although thermal simulation technology has a wide range of applications in battery thermal runaway protection design, in the existing technology, the current thermal runaway simulation only uses the external heating plate to input heat as a heat source, which cannot simulate the actual thermal runaway test process, resulting in a large deviation between the temperature field simulation results and the actual measured values ​​of thermal runaway.

[0003] Based on this, the present application provides a battery thermal runaway simulation solution that can simulate the thermal runaway process more accurately and comprehensively. Summary of the invention

[0004] In view of this, the present application provides a battery thermal runaway simulation method, device, equipment and readable storage medium. The present application achieves a comprehensive simulation of the thermal runaway dynamic process by splitting the battery cell modules and comprehensively simulating the heat source, thereby improving the accuracy of thermal runaway simulation.

[0005] A battery thermal runaway simulation method, comprising:

[0006] Generate a target cell disassembly model based on the original digital model and grid size of the target cell, in which the target cell roll is disassembled into a plurality of disassembly modules, and each of the disassembly modules is arranged in sequence from the side close to the external heat source;

[0007] Constructing a system simulation model according to the current simulated system insulation design digital model, the target cell disassembly model, and the thermophysical parameters set according to the materials of each cell component;

[0008] Inputting heat to the target cell by loading an external heat source, and detecting the module temperature of each of the split modules in the target cell split model and the average temperature of the split modules;

[0009] According to the module temperature of each of the split modules and the average temperature of the split modules, each of the split modules is respectively loaded with self-heating compensation and eruption compensation;

[0010] The overall average temperature of the target cell is detected to determine a thermal runaway determination result of the target cell.

[0011] Optionally, also include:

[0012] When the overall average temperature of the target cell reaches a preset thermal runaway trigger temperature, the average temperature of the target splitting module in the acceptor cell is detected, the acceptor cell is separated from the target cell by a heat insulating material in the system simulation model, and the target splitting module is a splitting module closest to the target cell in the splitting model corresponding to the acceptor cell;

[0013] According to whether the average temperature of the target split module reaches the preset self-heating trigger temperature, the safety assessment result of the current simulated system insulation design digital model is determined.

[0014] Optionally, the calculation formula for the module thickness of the split module is:

[0015]

[0016] in, is the thickness of the first split module starting from the external heat source side, is the mesh layer thickness, is the minimum grid size, is the thickness of the xth split module starting from the external heat source side, is the grid advancement coefficient.

[0017] Optionally, according to the module temperature of each of the split modules and the average temperature of the split modules, self-heating compensation and eruption compensation are loaded for each of the split modules respectively, including:

[0018] Determine a splitting module whose module temperature reaches a preset self-heating trigger temperature as a self-heating splitting module;

[0019] According to the self-generated heat of the target cell obtained by the test and the module thickness of the self-generated heat splitting module, the self-generated heat compensation heat is loaded into the self-generated heat splitting module by the volume ratio correction principle;

[0020] Determine a split module whose module temperature reaches a preset thermal runaway trigger temperature as a thermal runaway split module;

[0021] According to the calculated target cell eruption and combustion heat generation and the module thickness of the thermal runaway splitting module, the eruption compensation heat is loaded into the thermal runaway splitting module by the volume ratio correction principle;

[0022] Wherein, the self-heating trigger temperature is lower than the thermal runaway trigger temperature.

[0023] Optionally, the calculation formula for the self-generated heat compensation heat is:

[0024]

[0025] The calculation formula of the eruption compensation heat is:

[0026]

[0027] in, is the self-heat compensation heat of the i-th self-heat split module, is the self-generated heat energy correction coefficient of the i-th module, is the total self-generated heat during the cell ARC test process, is the eruption compensation heat of the i-th thermal runaway split module, is the thermal runaway ejection energy correction coefficient of the ith module cell, The target battery core emits combustion and generates heat. is the volume of the ith split module, is the total volume of the split module, and t is the test time.

[0028] Optionally, the target battery cell's eruption and combustion heat generation is calculated based on thermal runaway temperature collection data obtained from a thermal runaway test of a single battery cell and the battery cell mass loss rate;

[0029] The calculation formula for the heat generated by the target core ejection combustion is:

[0030]

[0031] in, The target battery core emits combustion and generates heat. is the difference in mass loss rate before and after thermal runaway of the battery cell, is the specific heat capacity, It is the multiple instantaneous temperature values ​​of the sampling point above the explosion-proof valve after the thermal runaway is triggered. is the ambient temperature value, is the thermal runaway eruption time, is the number of temperature values ​​collected for the thermal runaway test of the battery cell. is the Stokes constant for thermal radiation, is the surface reflectivity, A is the surface area of ​​the cell, and t is the test time.

[0032] Optionally, detecting the overall average temperature of the target cell to determine a thermal runaway determination result of the target cell includes:

[0033] Detect and calculate the overall average temperature of the target cell;

[0034] If the overall average temperature of the target cell reaches the preset thermal runaway trigger temperature, the thermal runaway determination result of the target cell is that the target cell triggers thermal runaway;

[0035] If the overall average temperature of the target cell does not reach the preset thermal runaway trigger temperature, the thermal runaway determination result of the target cell is that the overall target cell is not in thermal runaway.

[0036] A battery thermal runaway simulation device, comprising:

[0037] A cell disassembly unit, used for generating a target cell disassembly model based on the original cell digital model and grid size of the target cell, wherein the target cell roll is disassembled into a plurality of disassembly modules in the cell disassembly model, and the module thickness of each of the disassembly modules gradually increases from the side close to the external heat source;

[0038] A model building unit, used to build a system simulation model according to the current simulated system insulation design digital model, the target cell disassembly model and the thermophysical parameters set according to the materials of each cell component;

[0039] A heat source loading unit, used for loading the target heat to the target cell by loading the external heat source, and detecting the module temperature of each of the split modules in the target cell split model and the average temperature of the split modules;

[0040] A heat compensation unit, used for respectively applying self-heat compensation and eruption compensation to each of the split modules according to the module temperature of each of the split modules and the average temperature of the split modules;

[0041] The runaway determination unit is used to detect the overall average temperature of the target battery cell and determine a thermal runaway determination result for the target battery cell.

[0042] A battery thermal runaway simulation device, comprising a memory and a processor;

[0043] The memory is used to store programs;

[0044] The processor is used to execute the program to implement each step of the battery thermal runaway simulation method as described in any one of the above items.

[0045] A readable storage medium having a computer program stored thereon, characterized in that when the computer program is executed by a processor, each step of the battery thermal runaway simulation method as described in any one of the above items is implemented.

[0046] It can be seen from the above technical solutions that a battery thermal runaway simulation method, device, equipment and readable storage medium provided in the embodiments of the present application first generate a target cell disassembly model based on the original digital model and grid size of the cell. In the cell disassembly model, the target cell core is disassembled into a number of disassembly modules, and each of the disassembly modules is arranged in sequence from the side close to the external heat source. A system simulation model is constructed according to the digital model of the system insulation design currently simulated, the target cell disassembly model, and the thermophysical parameters set according to the materials of each cell component. Thereafter, the target heat is recorded to the target cell through an external heat source, and the module temperature of each disassembly module in the target cell disassembly model is detected. Secondly, according to the module temperature of each disassembly module, self-heat compensation and eruption compensation are loaded for each disassembly module respectively. Finally, the overall temperature of the target cell is detected to determine the result of the thermal runaway judgment of the target cell.

[0047] On the one hand, in view of the low thermal conductivity and large temperature gradient in the thickness direction of the battery cell, this application splits the target battery cell into multiple sub-modules, and considers the temperature change and self-heat generation of each sub-module at different time points, respectively, to achieve accurate simulation of the temperature gradient inside the battery cell. On the other hand, this application not only takes into account the heat input from the external heat source, but also fully considers the self-heat generated inside the battery cell during the thermal runaway process and the heat released by the combustion reaction. By introducing these internal heat sources, the simulation model can more accurately reflect the real source of heat in the thermal runaway process, thereby reducing the deviation between the simulation results and the actual situation. At the same time, this application realizes a dynamic and comprehensive simulation of the dynamic process of thermal runaway by simulating the continuous change process of multiple stages such as external heat input, self-heat generation inside the battery cell, and combustion reaction, further improving the accuracy and reliability of the simulation model. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0049] Figure 1 A schematic diagram of a system simulation model disclosed in an embodiment of the present application;

[0050] Figure 2 A temperature curve diagram of the battery cell after inputting heat from an external heat source disclosed in an embodiment of the present application;

[0051] Figure 3 A flowchart of a battery thermal runaway simulation method disclosed in an embodiment of the present application;

[0052] Figure 4 A schematic diagram of a target cell disassembly process disclosed in an embodiment of the present application;

[0053] Figure 5 A schematic diagram of the structure of a system simulation model disclosed in an embodiment of the present application;

[0054] Figure 6 A schematic diagram of a target cell test example disclosed in an embodiment of the present application;

[0055] Figure 7 A comparison chart of thermal simulation and measured temperature data of a thermal runaway target cell disclosed in an embodiment of the present application;

[0056] Figure 8 A schematic diagram of a battery thermal runaway simulation device disclosed in an embodiment of the present application;

[0057] Fig. 9 This is a hardware structure block diagram of a battery thermal runaway simulation device disclosed in an embodiment of the present application. DETAILED DESCRIPTION

[0058] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0059] In the study of thermal simulation, the applicant found that the prior art still has the following deficiencies:

[0060] First, when simulating heat sources, existing thermal runaway simulation models often only consider the heat input from external heat sources, while ignoring the possible self-generated heat generated inside the battery cell during thermal runaway and the heat released by the combustion reaction. This simplified heat source simulation method cannot accurately reflect the actual heat source during thermal runaway, resulting in a large deviation between the simulation results and the actual situation.

[0061] Secondly, since the thermal conductivity of the battery cell in the thickness direction is relatively low, when an external heat source triggers thermal runaway, the temperature gradient inside the battery cell will increase significantly. However, the existing technology has shortcomings in dealing with temperature gradients. It either completely ignores the self-heating process inside the battery cell or regards the self-heating as occurring simultaneously in the entire battery cell, which is inconsistent with the actual situation. This inaccurate temperature gradient processing method will further aggravate the distortion of the simulation results.

[0062] Third, thermal runaway is a complex dynamic process with multiple stages, involving external heat input, self-heating inside the battery cell, combustion reaction, heat propagation, etc. Existing technologies often have difficulty in fully and accurately simulating the continuous changes in these stages, especially when dealing with nonlinear changes such as self-heating and combustion reactions.

[0063] An embodiment of the present application provides a battery thermal runaway simulation method, which can be applied to a system or platform for performing thermal runaway simulation on a battery, and can also be applied to various computer terminals or smart terminals, and its execution subject can be a processor or server of the computer terminal or smart terminal.

[0064] First, the system simulation model for battery simulation is introduced, as well as the heating triggering method based on the battery cell and its thermal runaway heat generation mechanism. Figure 1 A schematic diagram of a system simulation model disclosed in an embodiment of the present application.

[0065] like Figure 1 As shown, under the continuous input of heat from the external heat source, the temperature of target cell No. 1 gradually rises. Since the insulation material is set between the cells, the thermal conductivity of the cell in the thickness direction is relatively small, resulting in a significant temperature gradient in this direction. The applicant has found that when the internal temperature of the cell reaches a specific self-heating trigger temperature T1 (usually between 60 and 120°C, depending on the design of the commercial lithium-ion battery), the cell begins to self-generate heat. This process can be keenly detected by the ARC (accelerating calorimeter) equipment, and the cell enters the self-heating stage. Figure 2 As shown. The fundamental reason for the self-heating of the battery cell is that the SEI (solid electrolyte interface) on the surface of the battery negative electrode material melts, which in turn triggers a violent reaction between the electrolyte and the negative electrode material, resulting in the release of heat. At this stage, the battery voltage will drop significantly.

[0066] With the continuous reaction and heat release of the negative electrode material and the electrolyte, the internal temperature of the battery cell further rises to about 200°C. At this time, the diaphragm undergoes closed-cell shrinkage due to the high temperature, resulting in local contact between the positive and negative electrodes and the formation of a micro-short circuit. The heat generated by the micro-short circuit and the original reaction heat work together to accelerate the overall shrinkage and disintegration of the diaphragm. When the temperature exceeds 200°C, the shrinkage rate of the diaphragm increases significantly, causing a large-scale internal short circuit between the positive and negative electrodes. The huge heat released by the internal short circuit and its accompanying side reactions further accelerates the disintegration process of the diaphragm, causing the battery cell voltage to drop sharply to 0V in a very short time (about 60 seconds).

[0067] That is, when the internal temperature of the battery cell rises to the thermal runaway trigger temperature T2, the battery cell enters a thermal runaway state, and the internal temperature rise rate increases sharply, far exceeding 1°C / s. In a high temperature environment, the internal materials of the battery cell undergo a violent redox reaction, generating a variety of flammable mixed gases including CH4, CO, H2, C2H4, etc. At the same time, the positive and negative electrode materials and aluminum foil melt at high temperatures. As the internal pressure continues to accumulate, once the pressure relief safety pressure of the explosion-proof valve is reached, an eruption will occur at the battery cell explosion-proof valve, releasing a large amount of explosive flammable mixed gases, high-temperature smoke particles, and copper foil fragments.

[0068] When conducting system-level battery thermal runaway tests, in order to ensure safety, once the cell temperature reaches T2 and the temperature rise rate exceeds 1°C / s, the power supply of the external heat source will be immediately cut off. In addition, when the internal temperature of the cell reaches T1, due to the dual effects of external heating and internal self-heating, the temperature rise rate of the cell will be significantly increased compared to the initial heating stage. When the cell temperature reaches T2 and triggers the explosion-proof valve to open, the internal combustion material will be ejected through the explosion-proof valve, and the cell temperature will rise sharply.

[0069] Next, the present application scheme is introduced. The present application proposes the following technical scheme, please see below for details.

[0070] Figure 3 This is a flow chart of a battery thermal runaway simulation method disclosed in an embodiment of the present application.

[0071] like Figure 3 As shown, the method may include:

[0072] Step S1, generating a target cell disassembly model based on the original cell digital model and grid size of the cell, wherein the target cell roll is disassembled into a plurality of disassembly modules in the cell disassembly model, and each of the disassembly modules is arranged in sequence from a side close to an external heat source.

[0073] Specifically, in view of the low thermal conductivity in the thickness direction of the battery cell and the large temperature gradient, this application decomposes the target battery cell into several split modules according to the design principles and splitting principles, while taking into account the solution accuracy and efficiency, and dividing the models into different grid sizes to simulate the heat transfer process of the battery cell thermal runaway test.

[0074] Further explanation: the overall structure of the battery cell consists of the top cover, shell and core. The top cover and shell are usually made of metal and plastic. During the thermal runaway process, they participate in heat generation but have limited heat absorption capacity. Therefore, in order to more accurately simulate and analyze the thermal runaway process, this program will focus on the battery core, which is a core component with a large mass ratio, significant heat absorption and self-heating characteristics.

[0075] To achieve this goal, Figure 4As shown in the figure, the battery cell roll is carefully split into several split modules, which are arranged in sequence starting from the side close to the external heat source. The thickness of the split modules can be equal, and the number can be set as needed to perform subsequent heat loading on each split model separately to improve the reliability of thermal runaway simulation.

[0076] In one embodiment, the module thickness of the split modules gradually increases from the side close to the external heat source, that is, the thickness of each split module shows a trend of gradually increasing. The first module, that is, the part closest to the external heat source, has the smallest thickness, followed by the second, third, fourth and other modules, with increasing thicknesses. Under the condition of a certain grid size, the smaller the module thickness of the split module, the fewer the total number of grids, the less the solution time, and the solution temperature can affect the subsequent split modules, that is, reducing the solution time of the split module close to the external heat source can ensure the relevance of the overall simulation and capture the dynamic changes of temperature over time.

[0077] In another embodiment, on the basis of gradually increasing the thickness of the module, the mesh size of each split module gradually increases from the side close to the external heat source, that is, the module thickness and the mesh size both show a trend of gradual increase. Such a design idea is mainly based on the following considerations: First, a smaller module size means a smaller total number of meshes, which reduces the consumption of computing resources and improves the solution efficiency. Secondly, a smaller mesh size can improve the solution accuracy. Since the battery cell part close to the external heat source will preferentially undergo self-heating or even combustion reactions, its solution accuracy is crucial for accurately predicting and simulating the heat conduction process of subsequent modules. Therefore, by reducing the thickness and mesh size of the split module close to the external heat source, it can ensure that high-precision data is obtained in the early stage of thermal runaway, laying a solid foundation for subsequent analysis.

[0078] For modules far away from external heat sources, when the overall temperature of the battery cell reaches the thermal runaway trigger temperature, the external heat source has stopped working and the remaining combustion heat is loaded at one time, so the solution accuracy requirements for this part are relatively low. Therefore, the thickness and mesh size of these modules can be appropriately increased to further optimize the calculation efficiency.

[0079] In one embodiment, the module thickness of the split module can be calculated according to the following formula:

[0080]

[0081] in, is the thickness of the first split module starting from the external heat source side, is the mesh layer thickness, is the minimum grid size, is the thickness of the xth split module starting from the external heat source side, is the grid advanced coefficient. In addition, based on the consideration of solution efficiency and accuracy Take an integer greater than 1, Take an integer greater than 2.

[0082] It should be noted that the grid size will affect the accuracy of the simulation solution. The smaller the grid, the higher the accuracy, but the total number of grids is also larger, and the solution time is longer. Due to the thermal runaway heating trigger mode, the initial split module takes the priority of heating heat, self-heating and combustion heat, and its temperature data accuracy directly affects the temperature field of subsequent modules. Therefore, in this embodiment, for the split module close to the external heat source, the grid size and thickness size are set to be relatively small. Further, for the first split module, the module thickness and grid size values ​​are set to the minimum.

[0083] Step S2, constructing a system simulation model according to the current simulated system insulation design digital model, the target cell disassembly model and the thermophysical parameters set according to the materials of each cell component.

[0084] Specifically, the system simulation model is further constructed based on the current simulated system insulation design digital model, the target cell disassembly model generated based on the original digital model and grid size of the cell, and the corresponding thermophysical parameters such as density, thermal conductivity and specific heat capacity set according to the material properties of each cell component (including the winding core, top cover and shell). The system simulation model can not only accurately reflect the interaction between the components inside the cell in the thermal runaway scenario, but also effectively simulate the inhibitory effect of the system insulation design on heat diffusion.

[0085] It is understandable that Figure 5 As shown, the system simulation model may also include a lower box, a liquid cooling plate disposed at the bottom of the lower box, a heat conductive material disposed between the battery cell and the liquid cooling plate, a heat insulating material disposed between the battery cells, an explosion-proof valve disposed in the lower box, a box cover, and a sealing ring between the box cover and the lower box. Correspondingly, the aforementioned components are all set with corresponding thermophysical parameters.

[0086] Step S3, loading target heat to the target cell through the external heat source, and detecting the module temperature of each of the split modules in the target cell split model.

[0087] Specifically, in the process of simulating thermal runaway of the target cell, firstly, by loading an external heat source, such as setting the power of the heating plate to 1000W, the target cell model is directly loaded with the corresponding target heat according to the power and heating time. Since the heating plate fits tightly to the target cell, the heat is quickly transferred to the inside of the cell, causing the temperature of the cell to gradually increase. As the heating time continues, the system simulation model can be used to detect the module temperature of each split module in the target cell split model. By outputting these temperature data through the simulation model, the thermal response characteristics of different positions inside the cell can be accurately captured.

[0088] Step S4: loading self-heating compensation and eruption compensation for each of the split modules according to the module temperature of each of the split modules.

[0089] Specifically, in order to further simulate the complex thermal behavior in real scenarios, the present application subsequently refined the temperature changes of each split module. When it is detected that the temperature of a module reaches the preset self-heating trigger temperature T1, the system automatically loads self-heating compensation for the split module to simulate the additional heat generated by chemical reactions or material degradation inside the battery cell. Similarly, when the temperature continues to rise to the preset thermal runaway trigger temperature T2, the system loads eruption compensation for the split module to simulate the violent exothermic reactions that may occur inside the battery cell, such as electrolyte evaporation, gas release, etc. This process not only improves the accuracy of the simulation, but also can more comprehensively reflect the behavioral characteristics of the battery cell at different stages of thermal runaway. It can be understood that, referring to the previous text, the self-heating trigger temperature T1 is less than the thermal runaway trigger temperature T2, which can be obtained by testing the battery cell with the ARC equipment, where the structure and material of the test battery cell are the same as those of the simulated battery cell.

[0090] Step S5: detecting the overall temperature of the target cell and determining a thermal runaway determination result of the target cell.

[0091] Specifically, in the final stage of the thermal runaway simulation, the overall temperature of the target cell is detected and based on this, the thermal runaway state of the target cell is determined. By integrating the temperature data of each split module, the system can calculate the overall temperature of the target cell, and then compare it with the preset runaway determination temperature T. If the overall average temperature reaches or exceeds T, the system determines that thermal runaway has occurred in the target cell. Furthermore, the overall temperature of the target cell can be taken as the overall average temperature of the target cell, so as to comprehensively reflect the thermal runaway of the cell, avoid excessive or low local temperature affecting the simulation accuracy, and improve the simulation reliability.

[0092] It can be seen from the above technical solutions that a battery thermal runaway simulation method, device, equipment and readable storage medium provided in the embodiment of the present application are used to predict thermal runaway of the battery. First, a target cell disassembly model is generated based on the original digital model and grid size of the cell. In the cell disassembly model, the target cell core is disassembled into several disassembly modules, and each of the disassembly modules is arranged in sequence from the side close to the external heat source. A system simulation model is constructed according to the digital model of the system insulation design currently simulated, the target cell disassembly model and the thermophysical parameters set according to the materials of each cell component. Then, the target heat is loaded to the target cell through an external heat source, and the module temperature of each disassembly module in the target cell disassembly model is detected. Secondly, according to the module temperature of each disassembly module, self-heat compensation and eruption compensation are loaded for each disassembly module respectively. Finally, the overall average temperature of the target cell is detected to determine the thermal runaway judgment result of the target cell.

[0093] On the one hand, in view of the low thermal conductivity and large temperature gradient in the thickness direction of the battery cell, this application splits the battery cell model into multiple sub-modules, and considers the temperature change and self-heat generation of each sub-module at different time points, respectively, to achieve accurate simulation of the temperature gradient inside the battery cell. On the other hand, this application not only takes into account the heat input from the external heat source, but also fully considers the self-heat generated inside the battery cell during the thermal runaway process and the heat released by the combustion reaction. By introducing these internal heat sources, the simulation model can more accurately reflect the real source of heat in the thermal runaway process, thereby reducing the deviation between the simulation results and the actual situation. At the same time, this application realizes a dynamic and comprehensive simulation of the dynamic process of thermal runaway by simulating the continuous change process of multiple stages such as external heat input, self-heat generation inside the battery cell, and combustion reaction, further improving the accuracy and reliability of the simulation model.

[0094] In some embodiments of the present application, the process of step S4, loading self-heating compensation and eruption compensation for each of the split modules according to the module temperature of each of the split modules, is introduced, which may specifically include:

[0095] Step S41: Determine a splitting module whose module temperature reaches a preset self-heating trigger temperature as a self-heating splitting module.

[0096] Step S42: according to the self-generated heat of the target cell obtained by the test and the module thickness of the self-generated heat splitting module, self-generated heat compensation heat is added to the self-generated heat splitting module by using the volume ratio correction principle.

[0097] Specifically, by detecting the module temperature of each split module, the split module that reaches the preset self-heating trigger temperature is identified as a self-heating split module. The system uses the volume ratio correction principle to load the self-heating compensation heat according to the self-heating heat of the target cell obtained by the ARC (accelerating calorimeter) device in an adiabatic environment and the module thickness of each heat-generating split module. Specifically, when the module temperature of a split module (such as the first split module) of the target cell reaches the preset self-heating trigger temperature, it indicates that self-heating begins to occur inside the split module. At this time, the heat input of the split module is determined by the external heat source and its own internal heat generation, so its self-heating process needs to be considered. During the test, the self-heating heat of the cell is obtained by the ARC device based on the heat compensation method, that is, when the ARC device detects that the cell temperature rises, its internal furnace temperature heater will work to heat the closed test environment to ensure that the temperature of the test cell is consistent with the external environment, so that the compensated heat can be regarded as the cell's own heat generation.

[0098] However, since the compensation heat obtained by the ARC test is based on the entire battery cell, it is necessary to load it into each split module based on the volume ratio correction principle. The calculation formula for loading the self-generated heat compensation heat to each self-generated heat split module based on the volume ratio correction principle is:

[0099]

[0100] in, is the self-heat compensation heat of the i-th self-heat split module, is the self-generated heat energy correction coefficient of the i-th module, is the total self-generated heat during the cell ARC test process, is the eruption compensation heat of the i-th thermal runaway split module, is the thermal runaway ejection energy correction coefficient of the ith module cell, The target battery core emits combustion and generates heat. is the volume of the ith split module, is the total volume of the split module, and t is the test time. Wherein, i can be equal to x. In addition, the self-heating compensation heat of the self-heating split module is corrected by the splitting order and the test time. Specifically, is the self-generated heat energy correction coefficient of the i-th module, which is inversely correlated with the cell module disassembly order i and the test time t, that is, the later the disassembly order and the longer the test time, the less self-generated heat the module shares, reflecting the phenomenon that in the actual thermal runaway process, the initial disassembly module enters the self-heating stage earlier and accumulates more heat.

[0101] It should be noted that the module temperature of the subsequent split modules is determined based on the self-heat compensation heat loaded in real time. When the i-th split module reaches the self-heat trigger temperature T1 and applies self-heat compensation, the temperature of other modules may also increase due to heat conduction. Therefore, the system needs to continuously monitor and determine whether the subsequent modules have also reached the self-heat trigger temperature T1, so as to load the corresponding self-heat compensation in time, and cycle the temperature judgment and compensation loading until the entire simulation process is completed. This process ensures that the simulation results can more accurately reflect the actual thermal behavior of the battery cell during thermal runaway.

[0102] Step S43: Determine a split module whose module temperature reaches a preset thermal runaway trigger temperature as a thermal runaway split module.

[0103] Step S44, according to the calculated target cell eruption and combustion heat generation and the module thickness of the thermal runaway splitting module, loading the eruption compensation heat into the thermal runaway splitting module by using the volume ratio correction principle.

[0104] Specifically, by monitoring the module temperature of each split module, the split module that reaches the preset thermal runaway trigger temperature is identified as a thermal runaway split module. After the self-generated heat is added to the battery cell split module, its temperature will rise significantly. The system continuously monitors the temperature of each split module. Once the temperature of the i-th module reaches the thermal runaway trigger temperature T2, it is considered that the trigger temperature has been reached inside the split module and a combustion reaction begins to occur. In order to accurately simulate the effect of combustion heat generation on the thermal temperature field in this process, the system adopts a method similar to that of self-generated heat loading, that is, loading according to the volume and energy correction principles. However, the calculation of combustion heat generation also needs to consider the effect of thermal radiation. Therefore, the calculation of the target cell eruption combustion heat generation includes factors such as mass loss rate, temperature change, and thermal radiation. The calculation formula for loading eruption compensation heat to each thermal runaway split module based on the volume ratio correction principle is:

[0105]

[0106] in, is the eruption compensation heat of the i-th thermal runaway split module, is the thermal runaway ejection energy correction coefficient of the ith module cell, The target battery core emits combustion and generates heat. is the volume of the ith split module, is the total volume of the split module, t is the test time. Similarly, i can be equal to x.

[0107] In addition, the eruption compensation heat of each self-heating split module is corrected by the splitting order and test time. is the thermal runaway ejection energy correction coefficient of the cell in the i-th module, which is inversely correlated with the cell module disassembly order i and the test time. That is, the larger i is, the larger the order is, and the longer the t time is. The smaller the value, the smaller the energy proportion, that is, the longer the heating time, the smaller the combustion proportion, and the longer the heating process, the longer the self-heating stage of the starting module, the greater the self-heating accumulation, and the more intense the combustion reaction, that is, the greater the contribution of the starting module to the combustion, that is, the larger i is, the longer t is, then The smaller.

[0108] The target battery cell's eruption and combustion heat generation is calculated based on the thermal runaway temperature collection data obtained from a thermal runaway test of a single battery cell and the battery cell mass loss rate;

[0109] The calculation formula for the heat generated by the target core ejection combustion is:

[0110]

[0111] in, The target battery core emits combustion and generates heat. is the difference in mass loss rate before and after thermal runaway of the battery cell, is the specific heat capacity, It is the multiple instantaneous temperature values ​​of the sampling point above the explosion-proof valve after the thermal runaway is triggered. is the ambient temperature value, is the thermal runaway eruption time (usually 0.5~2s), is the number of temperature values ​​collected for the thermal runaway test of the battery cell. is the thermal radiation Stokes constant (take 5.67*10 -8 W / m 2 *k 4 ), is the surface reflectivity (take 0<ε<1), A is the surface area of ​​the battery cell, and t is the test time. Through the actual test of the eruption and combustion heat generation, and through the module thickness, position, and test time, the eruption and combustion heat generation of each split module is comprehensively determined, and loaded into each split module respectively, to maximize the simulation of the real thermal runaway test process and reduce the deviation between the simulation results and the measured values.

[0112] It should be noted that the module temperature of the subsequent split modules is determined based on the eruption compensation heat loaded in real time. That is, the module temperature of the subsequent split modules can be determined based on the self-heat compensation heat and eruption compensation heat loaded by the same split module, or based on the self-heat compensation heat and eruption compensation heat loaded by multiple split modules, or based on the self-heat compensation heat and eruption compensation heat loaded by multiple split modules and the self-heat compensation heat loaded by a certain split module, wherein each split module can determine its corresponding self-heat compensation heat and eruption compensation heat according to the above formula. For example, when the temperature of the first module rises from T1 to T2, the self-heat compensation heat P1 and eruption compensation heat Q1 corresponding to the first module are loaded, then the second module determines the module temperature according to the model loaded with the heat. For another example, when the temperature of the first module reaches T2 and the temperature of the second module reaches T1, the self-generated heat compensation heat P1 and the eruption compensation heat Q1 corresponding to the first module and the self-generated heat compensation heat P2 corresponding to the second module are loaded, and the temperature of the third module is determined based on the aforementioned loaded heat.

[0113] This solution can simulate this process more carefully by splitting the modules and gradually adding heat based on temperature. Under the combined effect of external heating and self-generated heat, each split module of the battery cell will quickly reach the thermal runaway trigger temperature T2. The time scale of this process is consistent with the actual test situation, thus ensuring the accuracy and reliability of the simulation results. After that, the corresponding combustion heat generation is loaded to the thermal runaway split module. Under the heat transfer effect of the thermal runaway split module, the overall temperature of the target battery cell continues to rise.

[0114] It should be noted that the module temperature of the split module can be the average temperature of the module to avoid the accuracy affected by excessive local temperature difference, or the module temperature of the split module can be the maximum temperature of the module to further improve the safety of thermal simulation.

[0115] On this basis, the process of step S5, detecting the overall temperature of the target cell and determining the thermal runaway determination result of the target cell, may further include:

[0116] Step S51, detecting and calculating the overall temperature of the target cell;

[0117] Step S52: If the overall temperature of the target cell reaches the preset thermal runaway triggering temperature, the thermal runaway determination result of the target cell is that the target cell triggers thermal runaway;

[0118] Step S53: If the overall temperature of the target cell does not reach the preset thermal runaway trigger temperature, the thermal runaway determination result of the target cell is that the overall target cell is not in thermal runaway.

[0119] Specifically, the overall temperature of the target cell is detected, and based on the comparison result between the temperature and the preset runaway judgment temperature, it is determined whether the target cell has triggered thermal runaway. The preset runaway judgment temperature is determined based on factors such as cell material characteristics, design parameters, and safety standards, and is used to determine whether the cell has entered a thermal runaway state, and is generally the thermal runaway trigger temperature.

[0120] If the overall average temperature of the target cell reaches the preset thermal runaway trigger temperature, the target cell is judged to have triggered thermal runaway, and corresponding safety measures can be taken or the test results can be recorded. If the overall average temperature of the target cell does not reach the preset thermal runaway trigger temperature, the target cell is judged to have not experienced thermal runaway as a whole. This means that the cell is safe under the current test conditions, or its thermal runaway process has not been fully triggered. At this point, it can be determined whether the ordinal number of the split module is equal to the total number of split modules. If they are equal, it means that when all split modules have been fully loaded externally, the target cell has not triggered thermal runaway, and the target cell itself has extremely high thermal safety; if the ordinal number of the split module is less than the total number of split modules, return to the loop for judgment and record the heat. At this point, the system may continue to detect the temperature changes of the cell, or adjust the test conditions according to the test requirements to further evaluate the thermal safety performance of the cell.

[0121] In some embodiments of the present application, a solution for performing safety assessment on a system simulation model is also provided to determine whether the system-level design solution is reasonable and reliable. Based on the above content, the solution also includes:

[0122] Step S6, when the overall temperature of the target cell reaches a preset thermal runaway trigger temperature, the temperature of the target splitting module in the acceptor cell is detected, the acceptor cell is separated from the target cell by a heat-insulating material in the system simulation model, and the target splitting module is a splitting module closest to the target cell in the splitting model corresponding to the acceptor cell;

[0123] Step S7: Determine the safety assessment result of the current simulated system insulation design digital model according to whether the average temperature of the target split module reaches the preset self-heating trigger temperature.

[0124] Specifically, Figure 1As shown, when the overall temperature of the target cell reaches the preset thermal runaway trigger temperature, the temperature of the target split module in the recipient cell is detected. If the temperature of the target split module of the recipient cell reaches point T1, it indicates that the self-heating reaction has begun inside the recipient cell. This result shows that under the current thermal insulation design, heat transfer is not effectively blocked, and there are safety hazards in the recipient cell. The temperature of the target split module is selected as the basis for judgment because it is directly related to the potential risk of thermal runaway spread. If the temperature of the target split module in the recipient cell does not reach the self-heating trigger temperature T1, the possibility of thermal runaway spread is extremely low, and the thermal insulation design meets the requirements; otherwise, it may cause further thermal runaway problems, and the thermal insulation design needs to be optimized to ensure system safety. Among them, the recipient cell is separated from the target cell by a preset thermal insulation material in the system simulation model and is set on the side of the target cell away from the external heat source. The recipient cell is also split into multiple split modules, and the module thickness of the split module of the stressed cell can also be gradually increased from the side close to the target cell, where the target split module is the split module closest to the target cell.

[0125] The following is an example to illustrate: Figure 6 The battery pack design shown has multiple battery cells separated by thermal insulation materials. The present application tests the target battery cell by setting an external heat source on one side of the target battery cell. Figure 7 This is a comparison chart of the thermal simulation and measured temperature data of the thermal runaway target cell. Figure 7 It can be seen that compared with the prior art, the simulation data of the present application can more accurately reflect the actual situation during the thermal runaway process, and the deviation between the simulation results and the actual situation is small.

[0126] The specific simulation design is:

[0127] 1. Battery Cell Samples

[0128] 1) Cell type: LFP

[0129] 2) Capacity: 171AH

[0130] 3) SOC: 95%

[0131] 2. System module testing and simulation model status

[0132] 1) 1P121S

[0133] 2) Battery cell and ambient temperature: 25°C

[0134] 3) Original thickness of thermal insulation foam: 0.9mm

[0135] 4) Thermal management mode: with liquid cooling system without liquid cooling cycle

[0136] 5) Heating power: 1000W

[0137] A battery thermal runaway simulation device provided in an embodiment of the present application is described below. The battery thermal runaway simulation device described below and the battery thermal runaway simulation method described above can correspond to each other.

[0138] See also Figure 8 , Figure 8 A schematic diagram of a battery thermal runaway simulation device disclosed in an embodiment of the present application.

[0139] like Figure 8 As shown, the battery thermal runaway simulation device may include:

[0140] The cell disassembly unit 110 is used to generate a target cell disassembly model based on the original cell digital model and grid size of the target cell, in which the target cell roll is disassembled into a plurality of disassembly modules, and the module thickness of each of the disassembly modules is arranged in sequence from the side close to the external heat source;

[0141] A model building unit 120 is used to build a system simulation model according to the current simulated system insulation design digital model, the target cell disassembly model and the thermophysical parameters set according to the materials of each cell component;

[0142] The heat source loading unit 130 is used to load the target heat to the target cell by loading the external heat source, and detect the module temperature of each of the split modules in the target cell split model and the average temperature of the split modules;

[0143] A heat compensation unit 140, used to perform self-heat compensation and eruption compensation for each of the split modules according to the module temperature of each of the split modules and the average temperature of the split modules;

[0144] The runaway determination unit 150 is used to detect the overall average temperature of the target battery cell and determine a thermal runaway determination result for the target battery cell.

[0145] Optionally, the battery thermal runaway simulation device further includes:

[0146] A receptor battery unit, used for detecting the average temperature of a target split module in a receptor cell when the overall average temperature of the target cell reaches a preset thermal runaway trigger temperature, wherein the receptor cell is separated from the target cell by a heat-insulating material in the system simulation model, and the target split module is a split module closest to the target cell in the split model corresponding to the receptor cell;

[0147] The safety assessment unit is used to determine the safety assessment result of the current simulated system insulation design digital model according to whether the average temperature of the target split module reaches the preset self-heating trigger temperature.

[0148] Optionally, the calculation formula for the module thickness of the split module is:

[0149]

[0150] in, is the thickness of the first split module starting from the external heat source side, is the mesh layer thickness, is the minimum grid size, is the thickness of the xth split module starting from the external heat source side, is the grid advancement coefficient.

[0151] Optionally, the heat compensation unit performs a process of performing self-heat compensation and eruption compensation for each of the split modules according to the module temperature of each of the split modules and the average temperature of the split modules, which may include:

[0152] Determine a splitting module whose module temperature reaches a preset self-heating trigger temperature as a self-heating splitting module;

[0153] According to the self-generated heat of the target cell obtained by the test and the module thickness of the self-generated heat splitting module, the self-generated heat compensation heat is loaded into the self-generated heat splitting module by the volume ratio correction principle;

[0154] Determine a split module whose module temperature reaches a preset thermal runaway trigger temperature as a thermal runaway split module;

[0155] According to the calculated target cell eruption and combustion heat generation and the module thickness of the thermal runaway splitting module, the eruption compensation heat is loaded into the thermal runaway splitting module through the volume ratio correction principle.

[0156] Optionally, the calculation formula for the self-generated heat compensation heat is:

[0157]

[0158] The calculation formula of the eruption compensation heat is:

[0159]

[0160] in, is the self-heat compensation heat of the i-th self-heat split module, is the self-generated heat energy correction coefficient of the i-th module, is the total self-generated heat during the cell ARC test process, is the eruption compensation heat of the i-th thermal runaway split module, is the thermal runaway ejection energy correction coefficient of the ith module cell, The target battery core emits combustion and generates heat. is the volume of the ith split module, is the total volume of the split module, and t is the test time.

[0161] Optionally, the target battery cell's eruption and combustion heat generation is calculated based on thermal runaway temperature collection data obtained from a thermal runaway test of a single battery cell and the battery cell mass loss rate;

[0162] The calculation formula for the heat generated by the target core ejection combustion is:

[0163]

[0164] in, The target battery core emits combustion and generates heat. is the difference in mass loss rate before and after thermal runaway of the battery cell, is the specific heat capacity, It is the multiple instantaneous temperature values ​​of the sampling point above the explosion-proof valve after the thermal runaway is triggered. is the ambient temperature value, is the thermal runaway eruption time, is the number of temperature values ​​collected for the thermal runaway test of the battery cell. is the Stokes constant for thermal radiation, is the surface reflectivity, A is the cell surface area, and t is the test time.

[0165] Optionally, the process of the out-of-control determination unit detecting the overall average temperature of the target battery cell and determining the thermal runaway determination result of the target battery cell may include:

[0166] Detect and calculate the overall average temperature of the target cell;

[0167] If the overall average temperature of the target cell reaches the preset thermal runaway trigger temperature, the thermal runaway determination result of the target cell is that the target cell triggers thermal runaway;

[0168] If the overall average temperature of the target cell does not reach the preset thermal runaway trigger temperature, the thermal runaway determination result of the target cell is that the overall target cell is not in thermal runaway.

[0169] The battery thermal runaway simulation device provided in the embodiment of the present application can be applied to a battery thermal runaway simulation device. Fig. 9 The hardware structure diagram of the battery thermal runaway simulation device is shown in FIG. Fig. 9 , the hardware structure of the battery thermal runaway simulation device may include: at least one processor 1, at least one communication interface 2, at least one memory 3 and at least one communication bus 4;

[0170] In the embodiment of the present application, the number of the processor 1, the communication interface 2, the memory 3, and the communication bus 4 is at least one, and the processor 1, the communication interface 2, and the memory 3 communicate with each other through the communication bus 4;

[0171] The processor 1 may be a central processing unit CPU, or an application-specific integrated circuit ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of the present invention, etc.;

[0172] The memory 3 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), etc., such as at least one disk memory;

[0173] The memory stores a program, and the processor can call the program stored in the memory, wherein the program is used to:

[0174] Generate a target cell disassembly model based on the original digital model and grid size of the target cell, in which the target cell roll is disassembled into a plurality of disassembly modules, and the module thickness of each of the disassembly modules gradually increases from the side close to the external heat source;

[0175] Constructing a system simulation model according to the current simulated system insulation design digital model, the target cell disassembly model, and the thermophysical parameters set according to the materials of each cell component;

[0176] Inputting heat to the target cell by loading an external heat source, and detecting the module temperature of each of the split modules in the target cell split model and the average temperature of the split modules;

[0177] According to the module temperature of each of the split modules and the average temperature of the split modules, performing self-heating compensation and eruption compensation for each of the split modules respectively;

[0178] The overall average temperature of the target cell is detected to determine a thermal runaway determination result of the target cell.

[0179] Optionally, the detailed functions and extended functions of the program may refer to the above description.

[0180] The embodiment of the present application further provides a readable storage medium, which may store a program suitable for execution by a processor, wherein the program is used to:

[0181] Generate a target cell disassembly model based on the original digital model and grid size of the target cell, in which the target cell roll is disassembled into a plurality of disassembly modules, and the module thickness of each of the disassembly modules gradually increases from the side close to the external heat source;

[0182] Constructing a system simulation model according to the current simulated system insulation design digital model, the target cell disassembly model, and the thermophysical parameters set according to the materials of each cell component;

[0183] Inputting heat to the target cell by loading an external heat source, and detecting the module temperature of each of the split modules in the target cell split model and the average temperature of the split modules;

[0184] According to the module temperature of each of the split modules and the average temperature of the split modules, performing self-heating compensation and eruption compensation for each of the split modules respectively;

[0185] The overall average temperature of the target cell is detected to determine a thermal runaway determination result of the target cell.

[0186] Optionally, the detailed functions and extended functions of the program may refer to the above description.

[0187] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0188] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0189] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may 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 scope consistent with the principles and novel features disclosed herein.

Claims

1. A battery thermal runaway simulation method, characterized in that: include: A target cell disassembly model is generated based on the original digital model and grid size of the cell, wherein the target cell roll is disassembled into a plurality of disassembly modules in the target cell disassembly model, and each of the disassembly modules is arranged in sequence from a side close to an external heat source; Constructing a system simulation model according to the current simulated system insulation design digital model, the target cell disassembly model, and the thermophysical parameters set according to the materials of each cell component; Loading target heat to the target cell through the external heat source, and detecting the module temperature of each of the split modules in the target cell split model; According to the module temperature of each of the split modules, self-heating compensation and eruption compensation are respectively applied to each of the split modules; The overall temperature of the target cell is detected to determine a thermal runaway determination result of the target cell.

2. The method according to claim 1, characterized in that Also includes: When the overall temperature of the target cell reaches a preset thermal runaway trigger temperature, the temperature of the target splitting module in the acceptor cell is detected. The acceptor cell is separated from the target cell by a preset heat-insulating material in the system simulation model and is arranged on the side of the target cell away from the external heat source. The target splitting module is a splitting module closest to the target cell in the acceptor cell splitting model corresponding to the acceptor cell; According to whether the target split module temperature reaches a preset self-heating trigger temperature, a safety assessment result of the current simulated system insulation design digital model is determined.

3. The method according to claim 1, characterized in that The module thickness of each split module gradually increases from the side close to the external heat source, wherein the calculation formula of the module thickness of the split module is: in, is the thickness of the first split module starting from the external heat source side, is the mesh layer thickness, is the minimum grid size, is the thickness of the xth split module starting from the external heat source side, is the grid advancement coefficient.

4. The method according to claim 3, characterized in that According to the module temperature of each of the split modules, self-heating compensation and eruption compensation are respectively applied to each of the split modules, including: Determine a splitting module whose module temperature reaches a preset self-heating trigger temperature as a self-heating splitting module; According to the self-generated heat of the target cell obtained by the test and the module thickness of the self-generated heat splitting module, the self-generated heat compensation heat is loaded into the self-generated heat splitting module by the volume ratio correction principle; Determine a split module whose module temperature reaches a preset thermal runaway trigger temperature as a thermal runaway split module; According to the calculated target cell eruption and combustion heat generation and the module thickness of the thermal runaway splitting module, the eruption compensation heat is loaded into the thermal runaway splitting module by the volume ratio correction principle; Wherein, the self-heating trigger temperature is lower than the thermal runaway trigger temperature.

5. The method according to claim 4, characterized in that The calculation formula of the self-generated heat compensation heat is: The calculation formula of the eruption compensation heat is: in, is the self-heat compensation heat of the i-th self-heat split module, is the self-generated heat energy correction coefficient of the i-th module, is the total self-generated heat during the cell ARC test process, is the eruption compensation heat of the i-th thermal runaway split module, is the thermal runaway ejection energy correction coefficient of the ith module cell, The target battery core emits combustion to generate heat. is the volume of the ith split module, is the total volume of the split module, and t is the test time.

6. The method according to claim 5, characterized in that The target battery cell's eruption and combustion heat generation is calculated based on the thermal runaway temperature collection data obtained from a thermal runaway test of a single battery cell and the battery cell mass loss rate; The calculation formula for the heat generated by the target core ejection combustion is: in, The target battery core emits combustion to generate heat. is the difference in mass loss rate before and after thermal runaway of the battery cell, is the specific heat capacity, It is the multiple instantaneous temperature values ​​of the sampling point above the explosion-proof valve after the thermal runaway is triggered. is the ambient temperature value, is the thermal runaway eruption time, is the number of temperature values ​​collected for the thermal runaway test of the battery cell. is the Stokes constant for thermal radiation, is the surface reflectivity, A is the surface area of ​​the cell, and t is the test time.

7. The method according to claim 1, characterized in that The detecting the overall temperature of the target cell and determining the thermal runaway determination result of the target cell includes: Detect and calculate the overall temperature of the target cell; If the overall temperature of the target cell reaches the preset thermal runaway trigger temperature, the thermal runaway determination result of the target cell is that the target cell triggers thermal runaway; If the overall temperature of the target cell does not reach the preset thermal runaway trigger temperature, the thermal runaway determination result of the target cell is that the overall target cell is not in thermal runaway.

8. A battery thermal runaway simulation device, characterized in that: include: A cell disassembly unit, used for generating a target cell disassembly model based on the original cell digital model and grid size of the target cell, wherein the target cell roll is disassembled into a plurality of disassembly modules in the cell disassembly model, and each of the disassembly modules is arranged in sequence from a side close to an external heat source; A model building unit, used to build a system simulation model according to the current simulated system insulation design digital model, the target cell disassembly model and the thermophysical parameters set according to the materials of each cell component; A heat source loading unit, used for loading the target heat to the target cell by loading the external heat source, and detecting the module temperature of each of the split modules in the target cell split model and the average temperature of the split modules; A heat compensation unit, used for respectively applying self-heat compensation and eruption compensation to each of the split modules according to the module temperature of each of the split modules and the average temperature of the split modules; The runaway determination unit is used to detect the overall average temperature of the target battery cell and determine a thermal runaway determination result for the target battery cell.

9. A battery thermal runaway simulation device, characterized in that: including memory and processor; The memory is used to store programs; The processor is used to execute the program to implement each step of the battery thermal runaway simulation method according to any one of claims 1 to 7.

10. A readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, each step of the battery thermal runaway simulation method according to any one of claims 1 to 7 is implemented.

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