Experimental study on a novel safety strategy for lithium-ion batteries: Fire suppression and thermal runaway mitigation in confined spaces using heat-triggered Fire-extinguishing Polymer Composite (FEPC)

Thermal runaway (TR) in lithium-ion batteries (LIBs) has emerged as a critical factor limiting the safe advancement of energy storage technologies. Perfluorohexanone, an effective extinguishing agent for battery fires, can rapidly reduce temperature and mitigate fire behavior. However, its high volatility and deployment method limit its application in TR scenarios within confined and narrow spaces. This study introduces a novel Fire-extinguishing Polymer Composite (FEPC) containing perfluorohexanone, synthesized through the in-situ polymerization of microcapsules and epoxy resin materials, aimed at suppressing TR in LIBs. Laboratory-scale fire extinguishing performance tests demonstrated that the material can rapidly respond to release the extinguishing agent and effectively suppress flames. The inhibitory effects of FEPC on LIB TR were evaluated under both passive and proactive release conditions in confined spaces. The findings revealed that FEPC significantly inhibits TR propagation, mitigates fire behavior, and reduces mass loss. Notably, proactive release conditions exhibited a more pronounced inhibitory effect on TR, evidenced by higher critical runaway temperatures, extended propagation times, and reduced mass losses compared to those in passive release conditions. These conclusions offer innovative approaches and insights for developing fire-extinguishing agents in confined spaces and provide valuable references for the practical engineering design of thermal management (TM) modules in LIBs, with substantial potential for application.