Optimizing Type and Thickness of Fire-Resistant Materials for Liquid Nitrogen Suppression of Lithium-Ion Battery Fires

Lithium-ion batteries are widely used in electrochemical energy storage due to their advantages such as fast response and good scalability, but they are prone to thermal runaway (TR) under abusive conditions. Liquid nitrogen has been proven effective in suppressing lithium-ion cell TR in previous studies owing to its excellent cooling capacity. To further enhance the suppression capability of liquid nitrogen on lithium-ion cell TR, a method combining liquid nitrogen with fire-resistant materials was proposed. All experiments were conducted under strictly controlled conditions to ensure result comparability. Experiments on the synergistic suppression of lithium-ion cell TR propagation were conducted with the type and thickness of the fire-resistant materials as variables. The results demonstrated that installing porous fire-resistant materials inside the lithium-ion battery module significantly enhanced the efficacy of liquid nitrogen in suppressing TR propagation. The maximum rebound temperature of the cell after nitrogen injection cessation was reduced by up to 32.7% compared to the condition without fire-resistant materials. Both material characteristics and thickness influenced the heat exchange process—ceramic fiber aerogel, with its low thermal conductivity, achieved a maximum cooling rate of 2.45 °C/s on the TR cell surface, exhibiting the optimal enhancement effect; as the material thickness increased, the synergistic fire suppression performance was further enhanced with increasing material thickness, with the 9 mm thick ceramic fiber aerogel performing better than the thinner (6 mm and 3 mm) variants. The research findings provide a valuable reference for module-level thermal runaway suppression in energy storage systems.