Comparative Study on Thermal Runaway Characteristics of Lithium Iron Phosphate Battery Modules Under Different Overcharge Conditions

In order to study the thermal runaway characteristics of the lithium iron phosphate (LFP) battery used in energy storage station, here we set up a real energy storage prefabrication cabin environment, where thermal runaway process of the LFP battery module was tested and explored under two different overcharge conditions (direct overcharge to thermal runaway and overcharge to safety vent open-standing–recharge to thermal runaway). In this experiment, surveillance cameras, infrared imagers, temperature detectors, and gas detectors were used to guarantee all-around online observation. The experimental results show that under the conditions of these experiments, stop the overcharging process in time after the first battery safety vent is opened can effectively suppress the further development of thermal runaway, and maintain a safe state within 2 h. It also indicates that the thermal runaway process of LFP battery module changes with heat accumulation which needs reaction time, if the heat accumulation could be stopped in time, the occurrence of thermal runaway accidents would be avoided. This provides effective theoretical guidance for safety warning and fire protection of electrochemical energy storage stations with LFP battery system.