Abstract: Abstract: As an excellent halon substitute, C2HF5 has a good effect on extinguishing thermal runaway fires of lithium-ion batteries. The gas composition of the thermal runaway gas of the lithium-ion battery was obtained in previous studies.Using CHEMKIN-Pro, the promotion of C2HF5 and mixed gas on the lean burn side was studied from two aspects of radical concentration and sensitivity analysis by simulation. The results show that the concentration of radicals H, O, and OH on the fuel lean side reach the peak at Xa=0.04, with C2HF5 showing a promotion effect; on the fuelrich side, the concentration of radicals decreases with the increase of C2HF5, showing an inhibitory effect;in the sensitivity analysis, the elementary reaction R1: H+O2=O+OH is the most sensitive. On the fuel lean side, under low C2HF5 addition, the elementary reaction is dominated by promotion. As the addition of C2HF5 increases, the inhibitory effect continues to strengthen; on the fuelrich side, the addition of C2HF5 appears as an inhibitory effect. The process of interaction between C2HF5 and flame is controlled by the competitive relationship between self-combustion promotion heat effect and chemical suppression effect.

Key words: Key words: C2HF5, thermal runaway gas for lithium-ion battery, CHEMKIN-Pro, fuel lean side, radical concentration, sensitivity analysis