Refined study on lithium ion battery combustion in open space and a combustion chamber

Abstract More refined combustion tests on 18650-type lithium ion batteries (LIBs) are conducted both in open space (OS test) and a combustion chamber (CC test). High-speed camera is used to capture the fast rupture and ignition of LIB. In OS tests, jet-flame height increases with the state of charge (SOC), ranging from 0.095 to 0.217 m for 70-100% SOC cell. The ejecting velocity of fragments reaches 30 m s-1. In CC tests, the electrolyte solvent and flammable gas products are ignited by the ignition rods leading to deflagration and more complete combustion than that in open space. The predicted mass loss ratio of LIB is 14.36% agreeing with experiments. As SOC increases, more lithium metal is available in anode to react with electrolyte to generate more flammable gases. Higher SOC leads to higher specific combustion heat of the mixed gas products, thus increases the severity of thermal runaway and combustion. The total heat release of a LIB fire can be predicted by adding the contribution of all organics’ combustion heats based on thermodynamic data.