An experimental study on thermal runaway and fire behavior of large-format LiNi0.8Co0.1Mn0.1O2 pouch power cell

Lithium-ion batteries are widely promoted in contemporary energy storage and electric vehicles, but battery fires frequently occur, so their thermal runaway and fire behaviors need to be deeply understood. This study investigates the thermal runaway and fire behaviors of 78 Ah LiNi0.8Co0.1Mn0.1O2 pouch batteries under 10 - 50 kW∙m-2 incident heat fluxes, including the combustion behaviors, heat release, and flame temperature. Heat release rate (HRR) based on the oxygen consumption principle (OCP) is modified by measuring the oxygen production of the fully charged cathode during continuous heating. Results show that the heat contributed by the oxygen released from the cathode is negligible (accounting for about 5% of the total heat release (THR)). The 100% and 0% SOC cells follow two different kinds of combustion behaviors. The incident heat flux has little influence on the total burning time, HRR, and THR of 100% SOC cells. It is found that there is a correlation between the time to ignition and the incident heat flux, namely tig∼(Tig−T0q˙′′)0.71. Besides, a flame centerline temperature distribution description model based on a line fire source is established, which is helpful to understand the battery flame structure, and provides a reference for thermal protection and evaluation of the thermal hazard of power supply applications.