Experimental study of the effectiveness of three kinds of extinguishing agents on suppressing lithium-ion battery fires

The thermal runaway of a lithium-ion battery (LIB) often results in fires or even explosions. Thus, finding a proper, effective and clean extinguishing agent is imperative. In this paper, fire and extinguishing tests on commercially available large-scale LIBs with LiNixCoyMnzO2 (NCM)/graphite electrodes are investigated. Three different extinguishing agents including CO2, HFC-227ea and water mist were adopted. The results show that each agent can inhibit the combustion of the combustible gases and jet fire of the cell. However, a flame is observed during the release of CO2 and HFC-227ea, while no flame is observed in the case with water mist, which means that water mist shows a better suppressive effect than the other two extinguishing agents. The absence of these extinguishing agents was often accompanied with black smoke and violent jet fire. Moreover, the peak average temperatures before the extinguishing agents were depleted were 43, 75 and 133 °C lower, respectively, than that in the situation without an extinguishing agent. These results indicate that water mist has the best cooling effect comparing with CO2 and HFC-227ea, which has significant implications for the design of a LIB fire protection system.