Abstract: Using the self-designed experimental platform, simulating the external overheating scene of lithium battery with heating rod, the surface temperature and CO volume fraction of thermal runway of 18650 Lithium battery were compared under 95, 80 and 60 kPa respectively. The inhibitory effect of low-pressure twin-fluid water mist on the thermal runaway of Lithium batteries was researched. The results showed that low-pressure twin-fluid water mist can produce smaller droplet at low atomization pressure, which can effectively inhibit thermal runaway and heat propagation of Lithium batteries, and reduce CO production. The fine water mist of 1.2 MPa produces the smallest droplet and the best cooling effect. As the environmental pressure decreases, the effect of the suppression of water mist declines. Inert gas can be considered as atomizing gas to enhance the fire extinguishing effect.

Key words: Lithium-ion battery, thermal runaway, low pressure twin-fluid water mist, droplet particle size, suppression effect