Experimental study on fire suppression of NCM lithium-ion battery by C6F12O in a confined space

Abstract

To investigate the suppression effect of C₆F₁₂O on the thermal runaway (TR) of NCM soft-pack lithium-ion battery (LIB) in a confined space, a combustion and suppression experimental platform was established. A 300 W heating panel was employed as an external heat source to induce TR. Results indicate that, in the absence of agents, the TR process of the fully charged NCM soft-pack battery exhibited pronounced gas release and intense jet flames, with the entire event lasting approximately 20 s. The average peak temperature on the back side of the cell (T_b-max) could be reached up to 776.5 ℃, corresponding to an average peak temperature 539.8 ℃ in surrounding environment, highlighting the potential for severe thermal hazards. The critical extinguishing dose (X_ext) and the critical thermal suppression dose (X_sup) of C₆F₁₂O were determined based on its extinguishing and cooling effects. The application of C₆F₁₂O could lead to the extinguishment of battery flames within 3 s, with the X_ext not less than 2.62 kg/kWh. However, low dose (0.07 kg and 0.15 kg) of C₆F₁₂O can exacerbate the temperature rise of LIBs after TR, potentially leading to re-ignition. Whereas a dosage exceeding of X_sup = 5.48 kg/kWh can exert a positive suppression effect to counteract this influence. This research provides valuable insights for selecting the optimal C₆F₁₂O dosage and designing effective firefighting measures against LIB fires, while also offering novel research directions for extinguishing strategies.