Research on fire suppression of lithium-ion battery module in Li-ion battery energy storage system

To investigate the fire extinguishing efficacy of different mediums on failed liquid-cooled lithium iron phosphate battery modules in Li-ion battery energy storage system, a test platform was established for lithium battery system fire suppression. A thermal runaway event was induced in a lithium iron phosphate battery with a rated capacity of 230 Ah by overcharging at 1C, and by varying the extinguishing medium, we examined the effectiveness of both individual and combined usage of perfluorohexane and high-pressure water mist in suppressing battery thermal runaway. The results indicated that higher concentrations of perfluorohexane ($25 \%$) could swiftly extinguish open flames from lithium iron phosphate battery modules, significantly reduce battery temperature, and thereby lower the risk of thermal runaway, performing better than lower concentrations ($\mathbf{18 \%}$). By contrast, the fire extinguishing effect of high-pressure water mist was found to be weaker than that of perfluorohexane. Nevertheless, rapid heat absorption and phase transition of the mist could maintain characteristic gas concentrations below 400 ppm and continually cool the battery module. The combined use of high-pressure water mist and perfluorohexane significantly improved fire extinguishing efficiency, hastened the fire control process, and effectively reduced the concentration of combustible gases.