Quantitative analysis of eruption process of abused prismatic Ni-rich automotive batteries based on in-chamber pressure

Abstract

Lithium-ion battery (LIB) eruptions play an important role in battery fires in electric vehicles. This study aims to quantitatively reveal the eruption process of LIBs. A 50-Ah commercial prismatic cell with a Li(Ni0.6Mn0.2Co0.2)O2 cathode was triggered to thermal runaway using external heating in a sealed chamber with different initial nitrogen atmospheres under 0%, 25%, 50%, 75%, and 100% state of charge (SOC) values, respectively. Based on the in-chamber pressure under 100% SOC value, a quantitative analysis method for the LIB eruption process was proposed, and applied to the other SOC values at different test conditions. Results show that using a LIB eruption index (i.e., product of the in-chamber pressure rise rate and the cubic root of the chamber volume) based on the gas explosion index can effectively and quantitatively analyze the LIB eruption process at 100% SOC. According to the variation of the explosion indices with time, LIB eruption processes can be divided into ultrafast, fast, and slow phases. This quantitative analysis method is also effective in case of the eruption process at different SOC values under different conditions. Thus, the results of this study can provide guidance for fire early warning systems, fire suppression strategies, proper battery selections, and storage designs.