Carbon oxides emissions from lithium-ion batteries under thermal runaway from measurements and predictive model

A concentration test device was set up to study and analyze the thermal runaway gas production process in lithium-ion batteries. The experimental conditions for the research were determined by the influence of different external environments and gas flow rates on the thermal runaway process. Gas measurement and analysis of CO and CO₂ generated in thermal runaway process under different states of charge (SOCs), different ambient temperatures and different electric heating power were conducted. The following results were obtained. Under different SOCs, the concentrations of CO and CO₂ decreased as the charge capacity of the lithium-ion batteries decreased. Under different ambient temperatures, the concentration of CO₂ decreased with the decrease of the ambient temperature. However, the concentration of CO at the ambient temperature of 180 °C was higher than that at the ambient temperature of 220 °C. Under different electric heating power, the concentrations of CO and CO₂ decreased with the decrease of the electric heating power. Besides, Bayesian prior probability distribution theory was adopted to analyze the variations of CO concentration relative to time in the thermal runaway process, the results of which can predict thermal runaway state of lithium-ion batteries. The findings can serve to provide reference for accident prevention and control of thermal runaway of lithium-ion batteries.