Performance of Extinguishing Agents against Lithium-Ion Battery Fires

Abstract This study presents a systematic evaluation of fire suppression strategies for lithium-ion Battery Energy Storage Systems (BESS), specifically examining thermal runaway propagation in small domestic system (8 kWh). Five distinct suppression methods were evaluated: water mist, encapsulator agent (water mist with proprietary encapsulator), carbonate agent (water mist with ammonium bicarbonate), mixed agent (containing boron compounds and surfactants), and liquid nitrogen. Performed experiments revealed significant differences between suppression methods. Water mist and encapsulator agents demonstrated better performance, extending propagation delay times by 179% and 167%, respectively, compared to control tests without a suppression method. Registered maximum temperatures varied across methods from 780° to 890 °C. However, none of the tested methods prevented thermal runaway propagation entirely and were able to save the system from being destroyed. Critical safety concerns emerged regarding vapour cloud production, which correlated strongly with cooling effectiveness ( r = 0.87) but increased explosion risks. Statistical analysis confirmed significant method-dependent differences ( p < 0.001), with water mist and encapsulator agents reducing thermal runaway hazard ratios by over 70%. These results indicate that current suppression technologies can delay but not prevent thermal runaway propagation. Findings emphasize the need for integrated approaches combining efficient cooling with vapour management strategies, particularly for residential BESS installations.