Study on the combustion characteristics of lithium iron phosphate energy storage modules and the suppression effects of fire extinguishing agents

ZHANG Lei; HUANG Hao; MA Tianyi; FU Qiaoyu; ZHANG Yongfeng

doi:10.19996/j.cnki.ChinBatlnd.2025.02.003

Abstract：The thermal runaway,combustion characteristics,and suppression technology of lithium-ion batteries are important supports for ensuring the safe development of electrochemical energy storage.The thermal runaway and combustion characteristics experiments were conducted of a 100 Ah lithium iron phosphate battery module with 16 strings and 1 parallel under external heating conditions.The thermal runaway temperature and runaway combustion transition characteristics were obtained.On this basis,the fire extinguishing efficiency of perfluorohexane and hot aerosol fire extinguishing agents for this type of fire was compared and studied.As the result shows,during the thermal runaway of the 100 Ah lithium iron phosphate energy storage module,the temperature of the heating surface was 225℃,and the highest temperature of thermal runaway was 523℃.The ignition energy when the battery caught fire mainly came from the electrical short circuit inside the module.The extinguishing time of perfluorohexane fire extinguishing agent was about 9 s,and it had a certain cooling ability.The maximum cooling amplitude after spraying the agent was 78℃,but the temperature inside the battery module still exceeded 150℃.The module reignited after extinguishing the fire.The fire extinguishing performance of hot aerosol was better than that of perfluorohexane,with a fire extinguishing time of about 1 s.The module does not reignite after extinguishing the fire,but its cooling ability was not significant.Both perfluorohexane and hot aerosol could extinguish fires inside the module,but could not blocked the spread of thermal runaway in the module.They also could not effectively suppress electrolyte flow fires outside the battery module.Therefore,comprehensive protection of the inside and outside of the battery module should be emphasized in fire protection design.