Enhanced thermal insulation capabilities of SiO2 aerogel composite felts and their simulation in mitigating thermal runaway in power lithium batteries

Abstract

With the rapid development of new-energy vehicles, lithium-ion batteries (LIBs) have emerged as a critical power source for automobiles. In battery thermal management systems, thermal insulation sheets play a vital role by providing robust support for the safety and performance of batteries. This study fabricates thermal insulation sheets by impregnating silica aerogel into a silica fiber felt (SFF) substrate using the sol-gel method and supercritical drying technology. The integration of silica aerogel significantly reduces the thermal conductivity of the sheets, effectively enhancing the thermal management efficiency, while the SFF offers a solid guarantee for the battery's safety. Here, a range of silicon aerogel composite felts were crafted, employing SFFs with varying compositions (designated as low-content LSFF and high-content HSFF). The results showed that HSFF-75 exhibited the best performance, with a thermal conductivity lowered to 0.018 ± 0.001 W/(m·K), while maintaining good mechanical properties (maximum strain of 31.1 % and maximum stress of 2.3 MPa) and hydrophobicity (water contact angle of 130.5°). Simulation results demonstrate that HSFF-75 material significantly suppresses thermal runaway propagation, validating its protective efficacy for battery systems. Furthermore, the good thermal insulation of HSFF-75 helps reduce heat loss in cold conditions and improve the driving experience in low-temperature environments.