Thermal Management And Thermal Runaway Propagation Characteristics Of Lithium-ion Batteries Based On Phase Change Materials

With the increasingly prominent environmental problems,the rapid popularity of new energy vehicles,energy storage power stations and other new technologies have also been vigorously developed.The modular application of a large number of single batteries has also brought about the problem of battery heat dissipation and the "domino effect" caused by the thermal runaway of the battery,resulting in serious consequences.In this paper,simulation and experiment methods were adopted respectively to study and analyze the heat dissipation and thermal runaway phenomena of lithium ion battery modules using phase change materials.The main summaries are as follows:The use of phase change materials has obvious effects on improving the thermal management performance of lithium batteries and blocking the thermal runaway propagation of battery modules.The cooling mode of the finned shell has the best thermal management performance for the battery module,which has the best performance for both the maximum surface temperature and temperature difference of the battery module.The height and spacing of the fins also have an important effect on the heat dissipation performance.The higher the height,the smaller the spacing,the better the heat dissipation performance of the fins.At the same time,too small cell row spacing is not conducive to restrain the maximum temperature and temperature uniformity of the battery module;If the spacing is too large,the waste of PCM and the decrease of energy density will be caused,and the uniformity of temperature will also be adversely affected.The gap between the battery packs is filled with PCM,which has a significant effect on blocking the thermal runaway propagation of the battery pack.With PCM filling,only one battery of different SOC(State Of Charge)battery packs has thermal runaway,and no thermal runaway propagation has occurred.For the battery pack with PCM interstitial gaps,the row spacing was changed,and it was found that the thermal runaway propagation phenomenon was basically similar.Some and only the No.1battery had thermal runaway,but no thermal runaway propagation occurred.However,it is found that as the battery row spacing d1 increases,the surface temperature of the battery with the same label decreases.The larger the row spacing,the more the surface temperature decreases.A proper PCM filling volume has a positive effect on blocking the thermal runaway propagation of the battery pack.When the filling ratio of PCM is30%,50%,100%,only one battery of the lithium battery pack has thermal runaway,and the total mass loss ΔW of the battery pack is the same;but when the filling ratio of PCM drops to 10%,The battery pack has experienced serious thermal runaway propagation,and all batteries in the pack have experienced thermal runaway.The total heat release of the battery modules with 0% and 10% filling ratios is not just the superposition of the heat release of a single battery,and its total heat release is much higher than the sum of the heat release of a single battery.