A study on the fire behaviors of 18650 battery and batteries pack under discharge

In order to have a better understanding of the fire behaviors of lithium-ion battery (LIB) and batteries pack under discharge, a series of fire tests were conducted. The fire behaviors of LIB were characterized by parameters including the flame photographs, surface temperature, mass loss, radiative heat flux and hydrogen fluoride (HF) mass flow. The results indicate that the number of batteries will affect the fire behaviors of LIB. Pack with larger number of LIB possesses a faster temperature rise, a higher peak heat flux and total radiative heat, leading to a quicker thermal runaway. Additionally, the discharging treatment also has a significant impact on LIB. It can accelerate the warming-up process, increase the fire risks of LIB, decrease the combustion efficiency of LIB and reduce the radiative heat. This is the result of the heat generation during discharge and the more reactive materials inside the battery under discharge. Besides, the HF generated during tests is discussed in the paper to note the toxicity of the released gases in LIB fire.