Study on the explosion overpressure evolution characteristics of thermal runaway gas from lithium-ion batteries in confined spaces
Exploring the evolution characteristics of explosion overpressure of thermal runaway gas from lithium-ion batteries under confined spatial condition,formulating corresponding safety prevention and control strategies,are essential to reducing the safety risks of lithium-ion battery energy storage systems.In this study,the thermal runa-way gas components of lithium-ion batteries were measured through thermal abuse experiments.Subsequently,gas explosion experiments were conducted in a closed cylindrical container using the measured gas components,and based on OpenFOAM,large eddy simulation of the explosion experiments was performed,the evolution characteris-tics of explosion overpressure and its formation mechanism of thermal runaway gas from lithium-ion batteries in con-fined spaces were revealed.The findings indicate that the front flame propagation characteristics and explosion over-pressure evolution predicted by the simulations are consistent with experimental observations.In the early stage of ignition,a free propagating spherical flame is formed in the cylinder while affected by boundary constraints,gradu-ally developing into an ellipsoidal shape,then into a pair of planar flames propagating in opposite directions.30 ms after ignition,the turbulence significantly accelerates flame propagation,and the front surface of the flame exhibits a cellular structure due to the Darrieus-Landau instability.