A method for joint simulation of thermal runaway energy field of lithium battery in transport protective equipment

Abstract

The present application belongs to the technical field of lithium battery safety, and specifically relates to a kind of transport protection equipment inner lithium battery thermal runaway energy field combined simulation method.The simulation method accurately simulates the thermal runaway behavior of lithium ion battery under transport conditions, providing important scientific basis and data support for battery transport safety evaluation and protection equipment optimization design, which can effectively identify potential risks and guide the development of safety management measures.Based on the energy field distribution data obtained by simulation, the design of key components in the protection equipment can be optimized, such as improving the exhaust capacity of the pressure relief valve and the sensitivity of the gas sensor, to ensure timely response in the event of thermal runaway.In addition, the method can also provide key parameter support for the structural design of transport protection equipment and the development of thermal runaway early warning system.

Description

Technical Field

[0001] This invention belongs to the field of lithium battery safety technology, specifically relating to a joint simulation method for the thermal runaway energy field of lithium batteries in transportation protective equipment. Background Technology

[0002] With the widespread application of lithium-ion batteries in electric vehicles, energy storage systems, and other fields, the safety of their transportation has become an increasingly important concern. During transportation, lithium-ion batteries may experience thermal runaway due to external factors such as vibration, mechanical shock, or temperature fluctuations, leading to serious consequences such as high temperatures, gas release, and even fires and explosions. These accidents not only threaten the safety of people and property but also pose a challenge to the stability of the battery supply chain. Traditional battery safety assessments largely rely on physical experiments, observing the behavior by actually triggering thermal runaway. However, such methods have significant drawbacks: the experiments are costly, time-consuming, and difficult to comprehensively cover the various operating conditions that may be encountered during transportation.

[0003] Current research primarily focuses on the triggering mechanisms, kinetic modeling, and distribution characteristics of energy fields such as temperature, pressure, and gas fields in lithium-ion batteries. While some scholars have established relatively mature theoretical models for the internal thermal runaway process of batteries, research on thermal runaway behavior within confined spaces during transportation remains insufficient. Existing simulation methods are mostly concentrated on single operating conditions or laboratory settings, lacking a systematic simulation of the impact of complex environments on battery thermal runaway during transportation. Therefore, an efficient and accurate simulation method is urgently needed to simulate the thermal runaway behavior of lithium-ion batteries within confined transportation spaces and provide data support for the design of protective equipment and safety warning systems. Summary of the Invention

[0004] The purpose of this invention is to solve the problems existing in the prior art. In view of the thermal runaway behavior of lithium-ion batteries in confined spaces during transportation, this invention provides a joint simulation method for the thermal runaway energy field of lithium batteries in transportation protective equipment. The aim is to accurately simulate the distribution law of temperature field, pressure field and flue gas field when the battery undergoes thermal runaway under transportation conditions through numerical simulation technology, so as to reveal its energy field distribution characteristics.

[0005] This invention is achieved through the following technical solution:

[0006] A joint simulation method for the thermal runaway energy field of a lithium battery inside transport protective equipment, the method comprising the following steps: The first step is to create a 1:1 scale 3D confined space model in STAR-CCM+ software, and divide the 3D confined space model into three regions: the battery cell region, the protective equipment shell, and the air region. In each region, set the mesh generation requirements and boundary conditions. The second step involves using the three-dimensional confined space model established in the first step, combined with AMESim software, to obtain relevant parameters of the energy field during thermal runaway. These parameters include temperature, pressure, and flue gas; flue gas refers to the composition and content of each component. The third step is to obtain the temperature distribution curve, pressure distribution curve, and flue gas distribution curve based on the relevant parameters obtained in the second step. The fourth step involves using the temperature distribution curve obtained in the third step to guide the design of the temperature resistance performance of the transport protective equipment, the pressure distribution curve obtained in the third step to guide the design of the pressure resistance performance of the transport protective equipment, and the flue gas distribution curve obtained in the third step to guide the design of the early warning device of the transport protective equipment.

[0007] In the first step, the three-dimensional confined space model includes the dimensions of the transport protective equipment, the dimensions of the lithium battery, the number of lithium batteries, the arrangement of the lithium batteries, and the gap between the lithium batteries and the sidewalls of the transport protective equipment. In the first step, the meshing requirements for the cell area include setting the basic mesh size and setting the mesh generator; the basic mesh size is set to 25 mm, and the mesh generator settings include a polyhedral mesh generator, surface reconstruction and repair, mesh refinement strategy, and local densification near the trigger cell; The boundary conditions of the cell region are set as follows: solid region, activate the isolated solid energy model, enable constant properties, thermal conduction is three-dimensional steady state, heat source control function is introduced through FMI module to read AMESim heat generation power, realize thermal runaway triggering and thermal diffusion process modeling, initial condition is 25℃, static state; The meshing requirements for the protective equipment enclosure include the use of default and custom control settings, the setting of the basic mesh size, and the setting of the mesh generator; the basic mesh size is set to 25 mm, and the mesh generator is set to a polyhedral mesh generator. The boundary conditions for the protective equipment enclosure are set as follows: solid region, enable the separated solid energy model, set material properties, and set the thermally conductive boundary of the contact surface with the air domain; the thermally conductive boundary is a fixed heat flux or temperature. Meshing requirements for the air domain include setting the base mesh size and the mesh generator; the base mesh size is set to 25 mm, and the mesh generator is set to a polyhedral mesh generator. The boundary conditions for the air domain are set as follows: multi-component gas model (considering flue gas components such as CO and H2), using the standard k-ε turbulence model, activating the separated component model and the non-reactive gas flow model, considering high Reynolds number, wall treatment, three-dimensional steady-state solution, activating the FMI module to read the AMESim gas production rate, setting the cell valve port surface as the velocity inlet, controlling the jet velocity by the field function set in AMESim, applying refined control to the area near the battery, and ensuring clear thermal diffusion and gas release paths; In the second step, the method of using AMESim software is as follows: The STAR-CCM+ software is used to set thermal runaway triggering conditions and simulate the chemical reactions and heat release inside the lithium battery. At the same time, AMESim software is used to build a battery gas generation and temperature control module to simulate gas generation and temperature changes during thermal runaway. The FMU file is imported into the calculation module of the STAR-CCM+ software through AMESim software to realize data interaction between the two. The battery gas generation and temperature control module built using AMESim software includes a gas generation module and a temperature module. The gas generation module sets a gas generation rate threshold, and the temperature module sets a temperature threshold.

[0008] The beneficial effects of this invention are: This simulation method accurately simulates the thermal runaway behavior of lithium-ion batteries under transportation conditions, providing crucial scientific evidence and data support for battery transportation safety assessment and optimized design of protective equipment. It effectively identifies potential risks and guides the formulation of safety management measures. Based on the energy field distribution data obtained from the simulation, the design of key components in protective equipment can be optimized, such as improving the venting capacity of pressure relief valves and the sensitivity of gas sensors, ensuring timely response in the event of thermal runaway. Furthermore, this method can provide key parameter support for the structural design of transportation protective equipment and the development of thermal runaway early warning systems. For example, setting gas concentration thresholds and pressure change rates enables real-time safety monitoring and accident prevention. Compared to traditional physical experiments, this simulation method is lower in cost, shorter in cycle time, and can cover various transportation conditions, providing an innovative solution for technological advancements in the field of lithium-ion battery transportation safety. Attached Figure Description

[0009] Figure 1 Geometric model and mesh model; Figure 2 Schematic diagram of thermal runaway trigger source setup; Figure 3 A schematic diagram of simulation data of lithium-ion batteries in protective equipment, wherein Figure (ac) shows the battery temperature; Figure (d) shows the temperature of the protective equipment; Figure (e) shows the temperature field; Figure (f) shows the pressure field; and Figure (gh) shows the CO / H2 concentration in the flue gas field. Detailed Implementation

[0010] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0011] Example To better demonstrate the implementation of this technical solution, the following specific embodiments are disclosed: In this embodiment, a model is created based on the dimensions of protective equipment used in a specific project. Then, a model is created based on the lithium nickel cobalt aluminum oxide battery used in the project. Three boundary conditions are set, including trigger points for thermal runaway and monitoring points. Finally, the energy field distribution characteristics are obtained based on the simulation results. The specific steps are as follows: A joint simulation method for the thermal runaway energy field of a lithium battery inside transport protective equipment, the method comprising the following steps: The first step involves creating a 1:1 scale 3D confined space model in STAR-CCM+ software, based on the dimensions of the protective equipment used in the transportation of a specific project. This model is then divided into three regions: the battery cell region, the protective equipment casing, and the air region. Mesh generation requirements and boundary conditions are set for each region. Specifically, the protective equipment casing measures 2800 mm long, 2200 mm wide, and 860 mm high, with internal dimensions of 2600 mm wide, 2000 mm high, and 500 mm high. Mesh generation requirements for the casing include using default and custom control settings, setting the base mesh size, and configuring the mesh generator. The base mesh size is set to 25 mm, and the mesh generator is set to a polyhedral mesh generator. Boundary conditions for the casing are set as follows: solid region, enabling the separated solid energy model, setting material properties, and setting the thermal boundary at the interface with the air region; the thermal boundary is set to a fixed heat flux or temperature. The battery cell area uses 50Ah hard-shell nickel-cobalt-aluminum lithium-ion batteries, arranged with 150 individual cells in a 1-layer, 5-column, 30-row configuration to simulate the dense arrangement of batteries in actual transportation scenarios. Three thermal runaway trigger locations are set: the center, the edge, and the corner. Specifically... Figure 1As shown; the meshing requirements for the cell region include setting the basic mesh size and the mesh generator; the basic mesh size is set to 25 mm, and the mesh generator settings include a polyhedral mesh generator, surface reconstruction and repair, mesh refinement strategy, and local refinement near the trigger cell; the boundary conditions for the cell region are set as follows: solid region, activation of the separated solid energy model, enabling constant properties, thermal conduction as three-dimensional steady state, introduction of heat source control function through the FMI module to read AMESim heat generation power, realization of thermal runaway triggering and thermal diffusion process modeling, initial condition of 25℃, static state. The meshing requirements for the air domain include setting the basic mesh size and the mesh generator; the basic mesh size is set to 25 mm, and the mesh generator is set to a polyhedral mesh generator; the boundary conditions for the air domain are set as follows: multi-component gas model (considering flue gas components such as CO and H2), using the standard k-ε turbulence model, activating the separated component model and the non-reactive gas flow model, considering high Reynolds number, wall treatment, three-dimensional steady-state solution, activating the FMI module to read the AMESim gas production rate, setting the cell valve inlet as the velocity inlet, controlling the jet velocity by the field function set in AMESim, applying refinement control to the region near the battery, and ensuring clear thermal diffusion and gas release paths. The geometric model and mesh model are as follows: Figure 2 As shown.

[0012] The second step involves setting thermal runaway trigger conditions using STAR-CCM+ software to simulate the chemical reactions and heat release inside the lithium battery. The trigger conditions are a thermal runaway temperature of 142℃ and a heating power of 500W. Simultaneously, AMESim software is used to establish a battery gas generation and temperature control module to simulate gas generation and temperature changes during thermal runaway. The FMU file is imported into the STAR-CCM+ software's calculation module via AMESim software to achieve data interaction between the two. The battery gas generation and temperature control module established using AMESim software includes a gas generation module and a temperature module. The gas generation module sets a gas generation rate threshold: at 142℃, the gas generation rate is 20 m / s, and after 4 seconds, the gas generation rate is 0. The temperature module sets a temperature threshold: the battery begins to generate heat at 142℃ and stops generating heat at 512℃.

[0013] The third step involves obtaining the temperature distribution curve, pressure distribution curve, and flue gas distribution curve based on the relevant parameters obtained in the second step; from... Figure 3 The thermal runaway cell temperature curves in (a), (b), and (c) show that the rate of thermal runaway is strongly correlated with the trigger location; in terms of the rate of thermal runaway triggering, the corner location > the edge location > the center location. Furthermore, from... Figure 3 As can be seen from (d), the highest temperature on the surface of the protective equipment can reach 939K. Figure 3(e) It can be seen that the rate of change of ambient temperature is 187.17 K / s. Figure 3 (f) It can be found that the ambient pressure is 0.55 MPa when thermal runaway is triggered. Figure 3 (g) and (h) yield H2 and CO concentrations of 41611 ppm and 75958 ppm, respectively.

[0014] The fourth step involves designing the temperature resistance of the transport protective equipment based on the temperature distribution curve obtained in the third step. It is recommended that the upper limit of the protective equipment shell material under high-temperature conditions be no less than 1000 K. Metal composite materials with good thermal conductivity and high temperature resistance (such as aluminum alloy + ceramic coating structure) can be selected. The thickness of the heat insulation layer on the inner wall of the shell and the arrangement of the heat diffusion channels should be optimized to ensure that the structure does not deform or fail during the peak stage of thermal runaway (939 K, heating rate 187.17 K / s). Based on the pressure distribution curve obtained in the third step, the pressure resistance of the transport protective equipment is designed to guide the pressure resistance. It is recommended that the overall structural pressure resistance of the protective equipment be no less than 0.6 MPa. At the same time, pressure relief channels and safety pressure relief valves should be designed around the battery pack to disperse local stress concentration and prevent structural rupture caused by instantaneous high pressure. Compression stability can be improved by setting multi-stage slow-release pores or corrugated reinforcing ribs; based on the flue gas distribution curve obtained in the third step, the early warning device of the transport protective equipment is designed accordingly. It is recommended to install gas sensing modules on the top of the protective equipment and at the exhaust channel to monitor changes in H2 and CO concentrations, and set alarm thresholds of 3.0 × 10⁻⁶ for each. 4 ppm (H2) and 6.0 × 10 4 ppm (CO). Simultaneously, a multi-parameter coupled identification algorithm for temperature and pressure signals is used to achieve comprehensive early warning of the early stages of thermal runaway, and automatically activate ventilation and emergency pressure relief devices when the threshold is exceeded.

[0015] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A joint simulation method for the thermal runaway energy field of a lithium battery inside transport protective equipment, characterized in that... The steps of this method include: The first step is to establish a three-dimensional confined space model; The second step is to obtain the relevant parameters of the energy field during thermal runaway based on the three-dimensional confined space model established in the first step. The third step is to obtain the temperature distribution curve, pressure distribution curve, and flue gas distribution curve based on the relevant parameters obtained in the second step. The fourth step involves using the temperature distribution curve obtained in the third step to guide the design of the temperature resistance performance of the transport protective equipment, the pressure distribution curve obtained in the third step to guide the design of the pressure resistance performance of the transport protective equipment, and the flue gas distribution curve obtained in the third step to guide the design of the early warning device of the transport protective equipment.

2. The method for joint simulation of the thermal runaway energy field of a lithium battery in transportation protective equipment according to claim 1, characterized in that: In the first step, a three-dimensional confined space model with a 1:1 scale to the real scene is established in the STAR-CCM+ software. The established three-dimensional confined space model includes three regions: the battery cell region, the protective equipment shell, and the air region. Mesh division requirements and boundary conditions are set in each region.

3. The method for joint simulation of the thermal runaway energy field of a lithium battery in transportation protective equipment according to claim 2, characterized in that: In the first step, the three-dimensional confined space model includes the dimensions of the transport protective equipment, the dimensions of the lithium battery, the number of lithium batteries, the arrangement of the lithium batteries, and the gap between the lithium batteries and the sidewalls of the transport protective equipment.

4. The method for joint simulation of the thermal runaway energy field of a lithium battery in transportation protective equipment according to claim 3, characterized in that: In the first step, the meshing requirements for the cell area include setting the basic mesh size and setting the mesh generator; the basic mesh size is set to 25 mm, and the mesh generator settings include a polyhedral mesh generator, surface reconstruction and repair, mesh refinement strategy, and local densification near the trigger cell; The boundary conditions of the cell region are set as follows: solid region, activate the isolated solid energy model, enable constant properties, thermal conduction is three-dimensional steady state, heat source control function is introduced through FMI module to read AMESim heat generation power, realize thermal runaway triggering and thermal diffusion process modeling, initial condition is 25℃, static state.

5. The method for joint simulation of the thermal runaway energy field of a lithium battery in transportation protective equipment according to claim 4, characterized in that: The meshing requirements for the protective equipment enclosure include the use of default and custom control settings, the setting of the basic mesh size, and the setting of the mesh generator; the basic mesh size is set to 25 mm, and the mesh generator is set to a polyhedral mesh generator.

6. The method for joint simulation of the thermal runaway energy field of a lithium battery in transportation protective equipment according to claim 5, characterized in that: The boundary conditions of the protective equipment enclosure are set as follows: solid region, enable the separated solid energy model, set material properties, and set the thermally conductive boundary of the contact surface with the air domain; the thermally conductive boundary is a fixed heat flux or temperature.

7. The method for joint simulation of the thermal runaway energy field of a lithium battery in transportation protective equipment according to claim 6, characterized in that: Meshing requirements for the air domain include setting the base mesh size and the mesh generator; the base mesh size is set to 25 mm, and the mesh generator is set to a polyhedral mesh generator.

8. The method for joint simulation of the thermal runaway energy field of a lithium battery in transportation protective equipment according to claim 7, characterized in that: The boundary conditions for the air domain are set as follows: multi-component gas model, using standard k-ε turbulence model, activating the separated component model and non-reactive gas flow model, considering high Reynolds number, wall treatment, three-dimensional steady-state solution, activating the FMI module to read the AMESim gas production rate, setting the cell valve port surface as the velocity inlet, the jet velocity is controlled by the field function set in AMESim, applying refined control to the area near the battery, and ensuring clear thermal diffusion and gas release paths.

9. The method for joint simulation of the thermal runaway energy field of a lithium battery in transportation protective equipment according to claim 1, characterized in that: In the second step, relevant parameters of the energy field during thermal runaway are obtained based on the established three-dimensional confined space model and AMESim software. These parameters include temperature, pressure, and flue gas; flue gas refers to the composition and content of each component.

10. The method for joint simulation of the thermal runaway energy field of a lithium battery in transportation protective equipment according to claim 9, characterized in that: In the second step, the method of using AMESim software is as follows: The STAR-CCM+ software is used to set thermal runaway triggering conditions and simulate the chemical reactions and heat release inside the lithium battery. At the same time, AMESim software is used to build a battery gas generation and temperature control module to simulate gas generation and temperature changes during thermal runaway. The FMU file is imported into the calculation module of the STAR-CCM+ software through AMESim software to realize data interaction between the two. The battery gas generation and temperature control module established using AMESim software includes a gas generation module and a temperature module, wherein the gas generation module sets a gas generation rate threshold. Set the temperature threshold in the temperature module.

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