Study on the generation and diffusion law of thermal runaway gas in lithium battery energy storage system
Lithium-ion batteries produce large amounts of flammable gases during thermal runaway,which is the main risk of explosion in energy storage systems(ESS).In order to investigate the generation and diffusion law of combustible gas in thermal runaway of ESS,we firstly tested the gas production composition of a lithium iron phosphate battery under different thermal runaway triggering conditions through experiments.Based on the experimental results,a simulation model of gas generation and diffusion in thermal runaway process of prefabricated cabin energy storage system was established,and the combustible gas diffusion law after triggering thermal runaway in different positions of battery cells was analyzed.The results show that H2 accounts for about 30%of the released gases and is not affected by air components,making it more suitable for use as a warning gas in the early stages of thermal runaway in batteries.It is found that within 3 s of the opening of the explosion-proof valve of the electric cell,H2 is mainly concentrated in the area of the battery module.With the air-cooling cycle,it spreads to the external inter-area position of the battery module,and will spread to the whole storage battery compartment within 120 s.Based on this,the optimal gas sensor and duct arrangement scheme for this energy storage module is given.The results of this paper can provide a reference for the layout of combustible gas monitoring points and the design of emission paths in energy storage systems..
thermal runawaygas production characteristicslithium battery storage systemnumerical simulationgas diffusion
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