Innovative thermal management and thermal runaway suppression for battery module with flame retardant flexible composite phase change material

Thermal runaway severely affects the lithium batteries under conditions of non-normal forces or thermal abuse. In this study, a novel flame retardant flexible composite phase change material is successfully prepared, and a battery module based on it is designed and experimentally investigated. Herein, paraffin with high latent heat is performed as phase change material, Styrene-butadiene-styrene is employed as the supporting material, expanded graphite is used as the additive for thermal conductivity enhancement, and a flame retardant is utilized to suppress the heat diffusion and resistant flame. Experimental results reveal that a flame retardant flexible composite phase change material with 15 wt% flame retardant can achieve the optimum flame retardant effect, and its limiting oxygen index value can reach 35.9%. The battery thermal management with 15 wt% flame retardant composite phase change material can effectively avoid the heat accumulation of the battery module in the long cycle. In addition, thermal runaway trigger is simulated by heating rod at 200 °C, and the effect of the different composite phase change material modules on thermal runaway spread are compared. The result reveals that the flame retardant flexible composite phase change material could absorb and transfer the heat of the triggered battery timely and promptly, exhibiting a flame retardant effect necessary to avoid thermal runaway of the battery.