Scenario-based prediction of Li-ion batteries fire-induced toxicity

International audienceThe development of high energy Li-ion batteries with improved durability and increased safety mostlyrelies on the use of newly developed electrolytes. A detailed appraisal of fire-induced thermal andchemical threats on LiPF6- and LiFSI-based electrolytes by means of the so-called “fire propagationapparatus” had highlighted that the salt anion was responsible for the emission of a non negligiblecontent of irritant gas as HF (PF6-) or HF and SO2 (FSI-). A more thorough comparative investigation of thetoxicity threat in the case of larger-size 0.4 kWh Li-ion modules was thus undertaken.A modeling approach that consists in extrapolating the experimental data obtained from 1.3AhLiFePO4/graphite pouch cells under fire conditions and in using the state-of-the-art fire safety internationalstandards for the evaluation of fire toxicity was applied under two different real-scale simulatingscenarios. The obtained results reveal that critical thresholds are highly dependent on the nature of thesalt, LiPF6 or LiFSI, and on the cells state of charge. Hence, this approach can help define appropriate firesafety engineering measures for a given technology (different chemistry) or application (fully chargedbackup batteries or batteries subjected to deep discharge)