Full-scale experimental study on suppressing lithium-ion battery pack fires from electric vehicles

Electric vehicle (EV) fires resulting from the thermal instability of high-energy lithium-ion batteries (LIBs) have become a significant hazard to public safety. Effective and prompt fire-fighting methods for dealing with EV fires are required. A fire protection method referred to as electric vehicle fire enclosure (EVFE) was proposed in this paper based on EV fire characteristics. Full-scale fire experiments were employed to evaluate the fire extinguishing efficiency of various types of EVFE. Results showed that EVFE could effectively suppress the thermal runaway (TR) of full-size LIB packs in the EVs under these experimental conditions, and the battery packs did not occur re-thermal runaway after EVFE stopped working. The agent consumption of water EVFE was 0.628 m3/kWh, while that of foam EVFE was 0.743 m3/kWh. Moreover, the overheated battery packs had an interesting TR propagation mechanism that TR discretely spread among the cells. The TR critical temperature of unconnected battery modules was not suitable for illustrating the TR characteristics of circuit-connection battery modules. For the full-size LIB packs, the TR onset temperature ranged from 31.8 °C to 117.3 °C. These results provide an insight into the fire protection methods and TR characteristics of the LIB packs in EVs.