Study on Gas Production and Explosion Characteristics of Lithium-Ion Batteries During Thermal Runaway Under Different States of Health

Abstract

The rapid increase in power battery ownership means that a large number of batteries will be retired in the future. Currently, the cascade utilization of retired batteries is the most environmentally friendly and economical approach. However, many retired batteries may pose significant safety risks. In this study, we developed a gas production testing platform for new and aged lithium-ion batteries (LIBs) to address these concerns. Through conducting battery gas production tests, 20 L spherical gas explosion tests, and CHEMKIN software simulations, we carried out a comparative safety analysis from the perspectives of thermal runaway (TR) gas production behavior, explosion behavior, and underlying mechanisms. The results indicate that the gas production process of LIBs with different state of health (SOH) can be divided into six stages, with the proportion of flammable gases in the gas production decreasing in the order: 100% SOH > 70% SOH > 60% SOH > 80% SOH. The gas explosion process can be divided into four stages, with 70% SOH and 100% SOH batteries showing the most hazardous gas explosion behavior. The reactions R1: H + O2 = O + OH and R31: CO + OH = CO2 + H are the two elementary reactions that most strongly promote explosion, with the H radical being the most crucial factor in driving the gas production and explosion behavior of the batteries. This study helps to establish a comprehensive understanding of the gas production and explosion characteristics of LIBs, from fundamental mechanisms to engineering applications, laying the foundation for gas explosion hazard early warning and prevention throughout the battery life cycle.

Keywords: Lithium-ion batteries, Thermal runaway, Gas explosion, State of Health