Abstract: Thermal runaway experiments of lithium-ion batteries in different low-pressure environments (90, 70 kPa and 50 kPa) were carried out, and three lithium-ion battery thermal runaway experimental platforms were built using heating plates, radiant rings and radiant plates. Change the heating conditions and observe the thermal runaway fire behavior, temperature changes, heat release rate, total heat release, oxygen consumption and CO2 generation changes of the pouch package lithium-ion battery under low pressure. The decrease in pressure would cause insufficient oxygen in the combustion phase of the lithium-ion battery, resulting in insufficient combustion reaction between combustible substances and oxygen in the battery, resulting in a decrease in the peak temperature of the battery surface, heat release rate, total heat release and oxygen consumption, and thermal runaway. The time point was delayed backward. The thermal runaway or behavior of the battery was different under the action of different external heat sources. When the radiant ring was used as the external heat source, the battery is heated as a whole, and the internal side reaction rate is faster, and thermal runaway would occur earlier than the heating plate group and the radiating plate group. Under the pressure of 90 kPa, the CO2 volume of the radiant panel group is the largest, 2.743 7%, indicating that the combustion reaction was more thorough and the thermal hazard was stronger.

Key words: lithium-ion battery; thermal runaway; low pressure environment; external heat power