Research on the explosive combustion process of thermal runaway combustible gas of lithium battery for energy storage
In order to effectively prevent and control safety acci-dents in lithium iron phosphate battery energy storage power sta-tions,it is of utmost importance to evaluate the explosion risk of gases escaping from lithium iron phosphate batteries after thermal runaway.Based on the preliminary experimental results,this ar-ticle prepares premixed gases with different volume ratios of com-bustible gases and air released from thermal runaway of lithium iron phosphate batteries at different states of charge(SOC),and conducts research on the detonation process of premixed gases.The experimental results show that the explosion pressure of pre-mixed gas shows a pattern of first increasing and then decreasing with the increase of combustible gas volume fraction,and has little correlation with SOC;The maximum pressure pmax of pre-mixed gas deflagration increases with the increase of the propor-tion of combustible components such as H2,CO,and CH4 in the premixed gas;By conducting a 20 L ball explosion limit test,the explosion limits of premixed gases prepared for batteries with dif-ferent states of charge were obtained;Comparing two numerical calculation methods for explosion limits,it is believed that the Le Chatelier formula is suitable for calculating the lower explosion limit,while the adiabatic flame temperature method is suitable for calculating the upper explosion limit;According to the explosion index Kg,it can be seen that the destructive effect caused by ther-mal runaway gas explosion accidents in lithium iron phosphate bat-teries increases with the increase of SOC,indicating that high SOC lithium iron phosphate batteries are highly prone to fire and explosion hazards.It is recommended to take measures such as in-stalling combustible gas concentration monitoring devices to pre-vent and reduce the potential risks of the battery.
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