Abstract: Continuous and efficient anti-reignition and explosion suppression is the key to combat the thermal runaway fire of large-capacity lithium-ion battery. A new type of fire extinguishing and explosion suppression device using carbon dioxide-perfluorohexanone compound is proposed. The mixed compatibility test of liquid CO2 and perfluorhexanone was carried out, and the cold spray test, energy consumption analysis and simulated fire extinguishing test of large-capacity battery module were carried out. The results show that the low temperature and low pressure liquid CO2 stored at -20 ℃ can be completely miscible with perfluorohexanone in the range of 0~1.7 mass ratio to form a composite fire extinguishing medium. The composite fire extinguishing agent system can realize one-time injection and intermittent injection. The annual power consumption of fire extinguishing and explosion suppression system is only 10.48 kWh, with low power consumption and favorable economic performance. In the fire extinguishing test of 314 Ah lithium iron phosphate battery module, the open flame of the battery was extinguished within 1 s, no reignition and thermal runaway spread occurred, the single point temperature was as low as -72 ℃, and the cooling and anti-reignition and explosion suppression performance was excellent. Research results can provide a new efficient and economical solution for fire extinguishing and explosion protection of lithium batteries.

Key words: lithium-ion batteries, perfluorohexanone, carbon dioxide, low temperature, low pressure, compound fire extinguishing agent, fire extinguishing and explosion suppression