Experimental and kinetic study of thermal runaway gas explosion characteristics under different safety vent bursting pressures of 18650 battery

Abstract

In this study, explosion characteristics and laminar flame speeds of thermal runaway gases from lithium-ion batteries were investigated under different safety valve venting pressures (1 MPa, 2 MPa, and 3 MPa). Flammability limits (LEL and UEL) were experimentally determined, maximum pressure rise rate (dP/dt), and explosion overpressure for each condition. The results show that, the gases vented at 3 MPa exhibited the broadest explosive range (with the lowest LEL and highest UEL) and the greatest deflagration severity, achieving a peak (dP/dt) of 36.4 MPa/s and an explosion overpressure of 0.61 MPa. Laminar flame speed tests using a Bunsen burner showed that the 3 MPa vent gas had the fastes..