Inhibition effect and extinguishment mechanisms of YS1000 microemulsion for lithium iron phosphate battery fires

The inhibition of Lithium ion battery (LIB) fires has attracted more and more attention from the public. However, an effective fire-extinguishing agent used for LIB fires has not been reported. The use of water mist containing additives for LIB fires is a promising method. In this work, the YS1000 microemulsion was prepared. A fine water mist fire extinguishing system was established to study the extinguishment efficiency of the fire-extinguishing agents for LIB fires. The fire suppression efficiency of pure water, F-500 fire extinguishing agent, and YS1000 microemulsion for the 32135-type lithium iron phosphate battery (LFP) were compared in this paper. The fire extinguishment mechanism of YS1000 microemulsion was revealed by thermo gravimetry, differential scanning calorimetry, mass spectrometry (TG-DSC-MS) combined technology. The results showed that it took more than 30 s for pure water to extinguish the LFP fire. In the case of pure water, three batteries went into thermal runaway (TR). It only took less than 1 s for YS1000 microemulsion to extinguish the fire. In the process of extinguishing the fire, only one battery experienced TR. Compared with pure water, the total heat dissipation of YS1000 microemulsions to the batteries increased by 79 %. The YS1000 microemulsion extinguished the LFP battery fire mainly depending on phosphoric acid decomposing product of YS1000 microemulsion at high temperature. The phosphoric acid could eliminate H∙ and OH∙ free radicals in the flame. Research results are expected to provide a significant reference for the design of fire-extinguishing agents used for LIB fires.