Identification and characteristic analysis of powder ejected from a lithium ion battery during thermal runaway at elevated temperatures.

The thermal runaway of a lithium ion battery under abusive conditions has become an urgent problem in recent years. The thermal runaway generates flammable and toxic gases and ejects a hazardous black solid powder. Although relevant research on gas vented from thermal runaway has been studied in recent works, the composition, hazardous characteristics and formation process of the ejected powder remain unclarified. To investigate the hazardous characteristics of the ejected powder products and further provide insights into the thermal runaway mechanisms of lithium ion battery in terms of the identified components, a series of instrumental tests were performed and analyzed in this work. The results show that the powder ejected from the thermal runaway of a lithium ion battery is composed of carbon, organic chemicals, carbonate, metal, metal oxides and other impurities. Different states of charge of the lithium ion battery, heating modes and environmental atmospheres have certain effects on the formation of the ejected powder. These effects include the production of slightly different components in the ejected powder and changes in the particle sizes. The ejected powder is produced via a complex formation process and is hazardous due to its organic components, metal and metal oxides.