| Based on the research and summary of the thermal and uncontrolled ignition and explosion safety of on-board lithium-ion batteries at home and abroad,this paper proposes the research content of the current research on the explosive behavior of on-board lithium-ion battery explosion behavior,which is based on the theory of explosive mechanics.The numerical analysis logic system of the vehicle lithium-ion battery pack forms a scientific and reasonable calculation model.The on-board lithium-ion battery pack generates high temperature and high pressure under the thermal runaway fire and explosion conditions,and releases a large amount of heat,accompanied by the formation of gaseous products.This behavior is completely in line with the "explosive" explosion phenomenon,while the battery of the lithium battery pack of the vehicle It is the main energetic material,so the battery of the lithium-ion battery pack can be equivalent to a new type of "explosive",and the battery of a single lithium-ion battery pack can be equivalent to the equivalent equivalent of TNT explosive by energy matching method.The impact kinetics theory is used to calculate the explosion speed of the equivalent lithium battery pack,which provides a theoretical basis for the following simulation.Next,based on the stress wave impedance matching theory,the explosion simulation results of the lithium battery pack are carried out.Simulation analysis.The explosion model of the vehicle lithium-ion battery pack was established and calculated by ANSYS/LS-DYNA software.The simulation results show that due to the high-speed and high-pressure generated by the explosion shock wave and the explosive gas after the explosion of the lithium-ion battery pack,the explosion product is accompanied by obvious “splashing around” phenomenon,which has a negative impact on the personnel and structure of the vehicle.Since the wave impedance of each layer structure of the lithium-ion battery pack is similar to the wave impedance of the liquid scattering device in the stress wave theory,the scattered products are not suitable for wave impedance matching,which will enhance the scattering effect of the product,which is manifested by the velocity and scattering of the scattered products.The radius has increased significantly.According to the requirements of GB/T 18384.1-2015,the “splash” caused by the explosion behavior of individual battery packs should be avoided.Therefore,the structure and materials of the vehicle lithium ion group should be improved.An improved explosion model of the on-board lithium-ion battery pack was established to match the wave impedance of each layer and simulate it.The simulation results show that the pressure and velocity peaks accompanying the improved lithium battery explosive products decrease significantly,and the "splashing" behavior of the explosive products is effectively controlled.Through numerical simulation research on the lithium-ion battery pack of the vehicle,it is concluded that the structural wave impedance of each layer of the lithium battery pack is an important factor affecting its explosive behavior,and when the wave impedance of each layer is properly matched,the explosion of the lithium battery pack will be significantly weakened.The scattering effect reduces the negative impact of the explosive products on the personnel and structure of the vehicle,improves the safety of the lithium battery pack,and provides a theoretical reference for the lithium battery designer. |
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