Experimental study on inhibition effect of Novec-1230 on thermal runaway fire of lithium-ion battery packs induced by overcharging

Thermal runaway (TR) is the main safety issue of lithium-ion batteries (LIBs), especially for large-scale LIB packs which are composed of multiple modules in series and parallel combinations. Considering TR of LIB packs would be much more serious, effective prevention and control measures are urgently needed. This work investigates the suppressive effect of Novec-1230 on the fire induced by overcharging in a 3P4S lithium iron phosphate (LFP) battery module. The surface temperature, module voltage, temperature rise rate, temperature distribution in pack, total voltage, extinguishing process, battery wreckage, and real-time changes in gas concentration were determined. During the suppression process, Novec-1230 can effectively reduce the surface temperature of the battery without TR, and the cooling rate is up to −0.39 °C/s. For the battery that has started the TR, Novec-1230 cannot inhibit the chain reaction inside the battery. When Novec-1230 is released, the battery temperature still initially rises, but the temperature rise rate is significantly reduced. Once the heat generation of the battery gradually reaches a balance point with the heat absorption from the vaporization of Novec-1230 in its liquid state, the battery temperature begins to decline, the entire fire suppression process lasted for 81 s. After the flame is extinguished, the concentration of combustible gases begins to rise sharply, with the concentrations of H₂ and CO reaching 1078 ppm and 164 ppm, respectively. Under the inducement of an external igniter, the battery reignites. But the TR does not continue to propagate ultimately, and six batteries do not undergo TR. This work confirms the suppressive effect of Novec-1230 on large LIB packs, effectively mitigating the TR of batteries induced by overcharging.