Hazard analysis of thermally abused lithium-ion batteries at different state of charges

Temperature response, thermal decomposition, and gas generation are important metrics for evaluating thermal runaway hazards of lithium-ion batteries. In this paper, the hazards associated with thermally abused LiNi1/3Co1/3Mn1/3O2/graphite batteries at different state of charges (SOCs) are experimentally assessed. The results show that the maximum temperature of the battery during thermal runaway increases linearly with SOC, which is also accompanied by a linear decrease of the thermal runaway onset temperature. In addition, %%both the 90% and the 100% SOC batteries experienced some degree of gas deflagration and particle ejection that generated 1.22 g and 2.57 g of powders, respectively. While these powders are mostly contributed by the decomposition of battery cathodes, the gas deflagration can be mainly attributed to sparks that ignited the flammable gases released from the thermally abused batteries. Furthermore, this research also establishes a complete list of gas components observed at different SOCs, and the flammable ones are mainly carbon oxides, hydrocarbons, C2H4O2, and C2H6O. It is also observed that an increasing number of gas types will be generated at higher SOCs %, and some of these new components such as benzene can be harmful and toxic to the environment. Finally, this complete list of gas components can be used to identify characteristic gas types for an early warning mechanism of thermal runaway, which can be accomplished by installing appropriate gas sensors and monitoring their volume concentrations.