Lithium-ion Battery Energy Storage System Combustion And Explosion Simulation And Safety Protection Research

Lithium-ion batteries have the high energy density,long cycle life and environmental friendliness.The energy storage system using lithium-ion batteries has become the mainstream choice for grid energy storage.According to the characteristics of scale,access method,technical characteristics and application scenarios,energy storage systems can be divided into centralized and distributed.However,due to the flammability of the material of the lithium-ion battery,the fire of the battery will cause a chain reaction of adjacent batteries,resulting in the burning of the battery modules and clusters,and an explosion accident may occur in the confined space.In this paper,starting from the thermal runaway experiment of lithium battery for energy storage and the characteristics of gas explosion,the combustible gas that causes the battery to burn and explode is studied and verified.The typical scenarios of the centralized energy storage system and the distributed energy storage system are selected respectively.FLACS established a gas explosion model of a prefabricated cabin electrochemical energy storage power station and a lithium battery electric vehicle,and conducted a simulation study on the gas explosion accident and safety protection of the lithium-ion battery energy storage system.First,by analyzing the thermal runaway principle and combustion characteristics of lithium batteries,a thermal runaway experimental platform for lithium-ion batteries was built,and the lithium iron phosphate battery module was overcharged with constant current until the battery burned,and the overcharge of the lithium iron phosphate battery module was studied.Thermal runaway characteristics.It was found that the main component of the combustible gas that caused the explosion of the battery module during the development of thermal runaway was the vaporized electrolyte,not the gas generated by the thermal runaway reaction of the battery.Based on the vaporized electrolyte,a research method of lithium battery gas explosion is proposed and the model is verified.Then,the explosion characteristics of single-layer and double-layer energy storage compartments and the impact damage to the surrounding energy storage compartments were studied by establishing the physical model of the explosion of the prefabricated lithium battery energy storage power station.The simulation results show that the flame wave generated by the explosion in the energy storage cabin opens the pressure relief hole and spreads out of the cabin 0.5s after the explosion,and the peak value of the overpressure wave is significantly higher than the critical value of the pressure relief plate of the adjacent cabin,which may cause a series of explosions.In the explosion simulation of the double-layer energy storage tank,the upper layer of the energy storage tank has a wide space after the pressure relief hole is opened,and the pressure relief and cooling effect is more significant,and the high temperature and overpressure shock effect generated by the explosion is low.In order to prevent the explosion from spreading in the horizontal direction,it is proposed to install an isolation firewall outside the energy storage compartment,and the effectiveness of the isolation protection measures at different distances and heights is simulated and verified.Finally,the research on the overcharge combustion and explosion characteristics of lithium battery electric vehicles is carried out,and the explosion relief effects of different pressure relief designs are compared and analyzed.The simulation results show that the design of different pressure relief positions has an obvious effect on the diffusion direction of the explosion shock wave.When the pressure relief hole is arranged under the side of the battery compartment,the pressure relief effect is the best,which can effectively reduce the explosion intensity.Under a reasonable design,changing the size of the pressure relief hole and the opening pressure difference can reduce the impact on the surrounding vehicles and avoid igniting adjacent vehicles as much as possible.