Suppression of different positions thermal runaway in lithium-ion batteries using thermal insulation KGSA and phase-change SMEP both based on aerogel

Preventing the catastrophic propagation of thermal runaway within battery modules remains a critical challenge for battery safety. This study introduces a novel protective method that integrates a flame-retardant aerogel fiber felt thermal barrier KGSA with a self-extinguishing phase change composite SMEP to achieve superior thermal runaway suppression. Thermal runaway was triggered at different module locations to systematically evaluate the performance of these materials individually and in combination. When thermal runaway was triggered at the first cell (cell1), using SMEP alone delayed propagation (133.42 s, 243.10 s) but ultimately failed to prevent it. Either a standalone 3 mm KGSA barrier or its integration with SMEP in a sandwich configuration completely blocked thermal runaway propagation under cell1 triggering. For non-first cell trigging, which exhibited higher heat release rates, the combination of 2 mm KGSA and 1 mm SMEP delayed propagation (752.10 s, 664.12 s) without achieving full suppression. However, increasing the SMEP thickness to 1.5 mm within the composite system effectively mitigated thermal runaway across all triggering conditions. Combining thermal runaway behavior, combustion behavior, and the microstructure of materials after thermal runaway, the thermal runaway suppression mechanism of physical heat blocking and heat absorption was proposed, providing a novel strategy for battery safety design.