Numerical analysis on the combustion characteristic of lithium-ion battery vent gases and the suppression effect

The combustion of Lithium-ion battery (LIB) vent gases plays key roles in determining LIB fire hazard. Previous studies analyze the combustion of LIB vent gases without consideration of electrolyte. This work studies the combustion characteristic of LIB vent gases with dimethyl carbonate (DMC) addition. The flammability limit, laminar burning velocity (LBV), flame temperature and heat production are explored. For different components of LIB vent gases, most of combustion parameters decrease or remain unchanged with addition of DMC. It demonstrates that the fire risk of LIB vent gases reduces with DMC addition. Moreover, the influences of H₂O, C₆F₁₂O (Novec-1230) and POCH₃(OCH₃)₂ (DMMP) on LIB vent gases flame are investigated. At Φ = 1.0, all three suppressants suppress the flame. The lowest and highest suppression efficiency are H₂O and DMMP. At Φ = 0.45, Novec-1230 enhances combustion, but DMMP reduces LBV which is quite different from the enhancement effect on CH₄/air flame. This is mainly because of the reducing of O free radical and heat production. The sensitivity and path reaction of DMMP indicate that phosphorus species play important roles in suppressing lean flame. This work could deepen understanding of LIB vent gases combustion dynamics and provide guidance for choosing appropriate suppressants of LIB fire.