Trifunctional composite thermal barrier mitigates the thermal runaway propagation of large-format prismatic lithium-ion batteries

With the increasing energy density and capacity of lithium ion batteries (LIB), the safety problems caused by thermal runaway propagation (TRP) has become the most predominant hazard for electric vehicles (EVs) and energy storage systems (ESSs). Mitigating the TRP is significant for large-format LIB application. This study proposed a novel thermal barrier with nano-ceramic fiber, phase change materials (PCM) and mica cross skeleton. A 3 mm thermal barrier can effectively prevent the TRP behavior of a 153 Ah Li(Ni0.5Co0.2Mn0.3) (NCM523) battery module. The enthalpy of heat absorption of PCM is 1958 J/g. Besides, the mica skeleton can resist the extrusion pressure from the batteries, and the remaining nano-ceramic fiber provides insulation capacity. Moreover, the thermal barrier still maintains desirable heat insulation under pressure and high temperature operations, exhibiting high compressive strength. Furthermore, the thermal barrier can reduce the maximum temperature of the battery by about 10 °C during 2C charging and discharging conditions. This study guides the safety design of thermal barrier for large capacity LIB systems, contributing to the potential safety protection of next-generation EVs and ESSs.