Abstract: To explore whether the application of liquid water-based medium in battery thermal runaway suppression through immersion would cause secondary disasters and its actual effect on lithium battery thermal runaway suppression, this paper designed a long-term immersion test of a fully charged 1P9S-280 Ah series battery module in liquid water-based medium, as well as the suppression of thermal runaway propagation using liquid water-based medium. The results showed that an 840~8 370 kΩ resistance was formed between the positive and negative terminals of the battery after immersion in liquid water-based medium, indicating weak discharge of the battery in this medium and no risk of secondary disasters. Following the application of liquid water-based medium, the maximum temperature during the battery thermal runaway of the 1P9S-280 Ah battery series module was 398.1 ℃, and the maximum temperature of adjacent batteries was 125.6 ℃, demonstrating the significant suppression effect of liquid water-based medium on battery thermal runaway intensity and propagation.

Key words: liquid water-based medium, battery, thermal runaway, immersion, thermal diffusion；suppression