Study On Fire Spreading Rule And Flame Retardant Protection Of Lithium Ion Battery In Electric Vehicles

This thesis is based on the background of the current safety accident of electric vehicle,and systematically analysis the law of the combustion and spread of lithium-ion battery.Thus the best flame-retardant and thermal protection materials are selected for effective safety protection.Firstly,regarding to the combustion risk of the lithium-ion battery,the systematic researches of three aspects in terms of the fire behavior of lithium-ion battery,the law of the combustion and spread of lithium iron phosphate battery,and the law of the combustion and spread of LiCoMnNiO₂ battery respectively,are conducted based on the fact that power lithium iron phosphate battery is commonly used among current electric vehicles and the fact that the LiCoMnNiO₂ battery will continue to develop in the future.Through some combustion performance tests,the law of the combustion and spread of lithium-ion batteries is discovered by analyzing the behavior of the combustion and spread of lithium-ion battery with the method of lithium-ion battery combustion test.Then an assessment will be carried out on flue gas hazards caused by combustion explosion of the lithium-ion battery in accordance with relevant standards.Secondly,by conducting the flue gas toxicity test,the backside temperature test,the thermal conductivity test and the thermogravimetric analysis?TGA?test,the comprehensive evaluation test will be conducted on the different formulations and thickness of Ethylene Propylene Diene Monomer?EPDM?rubber,phenolic resin,and polyurethane fire-retardant coating of these three materials.Through comprehensive comparison,then select out the best performance of the flame-retardant and thermal protection material-the thickness of 3 mm plus flame-retardant EPDM rubber.Finally,the studies on the effect of the best flame retardant and thermal protection materials in the most dangerous LiCoMnNiO₂ battery's combustion explosion.The result shows that the battery pack without thermal protection,a total of five batteries exploded respectively;But LiCoMnNiO₂ battery pack with the best flame retardant and thermal protection materials,only one battery exploded under the direct burning while the other batteries of the same group did not explode,which proves that the best flame retardant and thermal protection material selected eventually works.