Characterization and assessment of fire evolution process of electric vehicles placed in parallel.

Electric vehicle (EV) fire accidents induced by the thermal runaway of li-ion batteries are increasingly frequent, and the fire dynamics of EVs parked in rows are still unclear. Hence the fire evolution process and characteristics of two parallel placed EVs were studied by analyzing the burning behaviors and thermal fields. The fire source was the battery pack of a battery electric vehicle (BEV). Results showed that the precursor to the BEV fire was the emission of white smoke from the chassis. Flames did not appear until the accumulated smoke exploded, and they engulfed both the EVs. The flame switched between momentum and buoyancy control on the vehicle scale. The maximums of the length and duration of the jet fires were determined. The maximum temperature of the EV fire was consistent with that of internal combustion engine vehicle (ICEV) fires, but the flame spread faster between the EVs compared to ICEVs. Pragmatic methods were proposed to quantify the fire evolution rate. The heat effect of the EV fire on humans was also quantitatively evaluated. These results provide a fundamental understanding of fire rules in a high EV concentration scenario. [ABSTRACT FROM AUTHOR]