Research On Collision Safety Performance Of Lithium-Ion Battery For Plug-In Hybrid Electric Vehicle

With the popularity of electric vehicles,people are paying more and more attention to it.Although electricity is a clean,efficient and inexhaustible source of energy,But as a carrier of electricity-battery,not so perfect.There is no doubt that electricity,as an ideal source of energy,it will replace traditional fossil energy.But as an industry practitioner must face the drawbacks of electric vehicles.Safety,as the basic requirement of automobile,should be the focus of research.This paper starts with the internal microstructure of the battery,study the nature of its flammable and explosive.Damage to the battery structure caused by mechanical incentives,short circuit of positive and negative electrodes causes a sharp rise in internal temperature.The ultimate cause of combustion of the battery is the root cause of most accidents.So how to reduce the damage to the battery during the development of electric vehicle safety performance? How to evaluate the damage tolerance of battery cells? How to guide the design in Practical engineering application is a difficult problem that we need to solve.Battery as a "sandwich" structure,first we did a local extrusion test,understand the structural damage mechanism of the battery cell.Initially defined the damage threshold of the battery.To guide the design in engineering,using the finite element method,establish a complete model that includes all the components of the battery cell.By disassembling the battery cells,measure the basic physical parameters of all materials,and design mechanical properties experiment,study the constitutive relation of materials,make material model for simulation.After repeated testing,designed a set of practical solutions,verify the calibration using a partial extrusion test of two battery cells.Simulation results show high consistency with experimental data,it can effectively judge the risk of battery thermal runaway.Finally in practical application,we use the complete finite element model of the battery cell that analyzes whether the safety of lithium-ion battery pack of a hybrid vehicle meets the regulations.On the basis of this,the bottom of the least protective capacity of the battery pack is selected,in the case of a foreign body intrusion assess damage to the battery and risk of thermal runaway.Designed three sandwich protection structures,comparative analysis of protective performance and reduce the amount of foreign body intrusion to avoid internal short circuit of the battery cell.Using practical examples to show significance of this scheme for the development of safety performance of electric vehicles.