Numerical Study On The Thermal Runaway Propagation Of Lithium-ion Power Battery Using Phase Change Material For Thermal Management

Increasingly serious environment problems and energy crisis have proposed a sever challenge to the growth of traditional automotive industry in China.However,clean energy vehicles with low fuel consumption and high efficiency offered an effective solution to the problems and given considerable attention by the public.With the popular of clean energy vehicles,security problems of the vehicle power batteries have emerged in an endless stream,which seriously hampered the rapid development of the clean energy automotive industry.The security problems of power batteries mainly involve high temperature,burning and explosion caused by thermal runaway.Several work has been done revolving around the thermal runaway of lithium ion batteries.The mechanism of thermal runaway was analyzed.The heat model has been built with the internal exothermic auxiliary reaction and the heat generation from short-circuit current both included.Numerical simulations aiming at penetration,hyper thermal abuse and hot box test with ARC have been done.The time-varying temperature and exothermal reaction during the process of three modes have been analyzed in detail.A Solid-liquid phase change thermal model has been built based on lattice Boltzmann method.The process of thermal runaway combined thermal runaway model and thermal management with phase change material(PCM)has been analyzed,the effects of composited PCM with different components to the process of thermal runaway has been simulated too.According to the researcher report,thermal runaway caused by penetration is the most violent.With the three trigger modes,the first quick rising of the temperature of the battery is caused by the heat production of internal short circuit,electrolyte decomposition and internal short circuit respectively.The results also show that,high-temperature performance of separator and thermal stability have greatest impact on the process of thermal runaway.The analysis of the process indicates that thermal runaway show the character of “locality” under the thermal management with PCM,so the PCM can protect batteries from the high temperature caused by thermal runaway.Comparing with composed PCM,pure wax gives more help to delay the propagation of thermal runaway with its low coefficient of heat conductivity,high latent heat and high specific heat.