Suppression capacity and environmental impact of three extinguishing agents for lithium-ion battery fires

Fire suppression and rapid cooling methods are required to reduce the risk of battery fires. However, the liquid and solid residues generated during fire extinguishing pose a risk to the environment and human health. With the aim of correlating the extinguishing efficiency and environmental impact of the residues, fire tests were carried out on NMC lithium-ion pouch cells using different agents, namely water mist, F-500 water additive 2 % (v/v) and CO₂. The combination of cell temperature measurements and videos allowed the efficiency of the extinguishing agents to be assessed. It was found that the efficiency of the water-based agents was higher than that of the gaseous agents (cooling rate of 30.5 ± 4.9 °C/s for water mist, 36.5 ± 6.4 °C/s for F-500 and 20.0 ± 1.4 °C/s for CO₂). Analysis of solid and liquid residues using gas chromatography and induced coupled plasma showed that the use of F-500 resulted in a higher (one order of magnitude) concentration of VOCs in solid residues compared to the other extinguishing agents. The comparison of these concentrations of VOCs with the limits established for waste (EU Regulation N. 1357/2014) showed that the solid residues did not exceed the concentration limit for classification as hazardous waste. Regarding the concentration of metals, the highest values in the solid and liquid residues are due to Li, Ni and Cu. Based on these values, all solid samples can be classified as carcinogenic and toxic for reproduction. While the concentration of metals in the liquid residues was higher than the limit value that poses a risk to aquatic organisms. The overall results showed the need for site remediation and waste management procedures in the event of a major accident.