Experimental investigation of a micelle encapsulator F-500 on suppressing lithium ion phosphate batteries fire and rapid cooling

Thermal runaway (TR) in lithium-ion batteries (LIBs) and LIB fires have attracted a considerable amount of attention. In this study, the micelle encapsulator F-500 was experimentally investigated to understand its extinguishing effect and cooling capacity for lithium iron phosphate (LFP) cells in modules. The gases produced from the batteries were collected and analysed. The extinguishing effectiveness and cooling capacity of a 3% F-500 solution and pure water mist (WM) were compared and discussed. Furthermore, the concentration of H₂ was evaluated during the tests. The experimental results showed that H₂ is the major gas released during thermal runaway. The combustion of LFP batteries requires external ignition and fire-intensified TR propagation in the LFP battery module. The cooling capacity of the 3% F-500 solution was appropriately three times that of WM according to temperature reduction calculations. The peak concentration for H₂ was 14 ppm when the micelle encapsulator was employed, while the peak concentration was 217 ppm when WM was applied. The control mechanisms were qualitatively discussed by comparing the connection between thermal runaway and fire progress. The cooling effect was identified as the most significant factor not only for rapidly extinguishing LIB flames but also for preventing TR propagation. These results are expected to provide guidelines for fighting LIB fires and for cooling LIB systems.