Suppressing thermal runaway propagation of nickel-rich Lithium-ion battery modules using silica aerogel sheets

Suppressing thermal runaway (TR) propagation within Lithium-ion battery (LIB) modules/packs/systems is one of the key factors to ensure the safety utilization of electric vehicles and energy storage systems. This contribution aims at introducing Silica Aerogel Sheets (SAS) into high energy density modules to suppress the TR propagation. The SAS, synthesized via a sol-gel process followed by supercritical fluid drying, possess almost an ideal thermal insulator characteristic due to the low thermal conductivity of 0.020 W/(m·K) at room temperature. The SAS are inserted between two adjacent pouch cells (LiNi0.86Co0.07Mn0.07O2/graphite, 320 Wh.kg−1) to assemble high energy density modules. A single pouch cell, subjected to the TR test with an Accelerating Rate Calorimetry, releases a huge amount of heat energy (1083 kJ/kg) with the maximum temperature beyond 800 °C. In the open area test site for TR propagation experiments, it can be observed that violent jet and flame burst from the cell, which is designed to undergo TR first and trigger the TR propagation of the modules. The results show that only one single layer of SAS cannot stop the TR propagation or fire spreading. However, more layers of SAS (three in the experiments) can successfully suppress the TR propagation and block fire progression. The temperature of the adjacent cell only reaches 105.4 °C. Therefore, the SAS with acceptable thickness can suppress the TR propagation successfully to improve the safety of the LIB modules.