An analysis of li-ion induced potential incidents in battery electrical energy storage system by use of computational fluid dynamics modeling and simulations: The Beijing April 2021 case study

To further grasp the failure process and explosion hazard of battery thermal runaway gas, numerical modeling and investigation were carried out based on a severe battery fire and explosion accident in a lithium-ion battery energy storage system (LIBESS) in China. The composition and transport law of gas caused by large-scale LIB failure were theoretically analyzed, and the explosion risk of thermal runaway gas mixture in complex space after accidental ignition were systematically discussed by the computational fluid dynamics (CFD) technology. After the investigation, the underground cable trench is the key channel that causes the thermal runaway gas of lithium iron phosphate batteries to be transported to the building 20 m away and induces the explosion. After about 8500 s of battery burning, the average concentration of the thermal runaway mixed gas diffused from the cable trench is 16.4%. The arrangement of obstacles in the accident building is the main factor determining the explosion overpressure of thermal runaway gas, and the overpressure generated at the end of the obstacle path exceeds 70 kPa. Multiple windows in the battery room play an effective explosion-venting effect, but increase the damage range of outdoor high-temperature flame. In addition, the System-Theoretical Accident Model and Processes (STAMP) was used to analyze the causes of the accident, and the safety constraints that should be imposed by the three control levels of the government, functional departments and energy storage power stations were introduced to prevent battery failure and fire accidents in the BESS. The research method and analysis results will provide important ideas and reference for the investigation of fire and explosion accidents in BESS.