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

Abstract The development of high energy Li-ion batteries with improved durability and increased safety mostly relies on the use of newly developed electrolytes. A detailed appraisal of fire-induced thermal and chemical threats on LiPF 6 - and LiFSI-based electrolytes by means of the so-called “fire propagation apparatus” had highlighted that the salt anion was responsible for the emission of a non negligible content of irritant gas as HF (PF 6 − ) or HF and SO 2 (FSI − ). A more thorough comparative investigation of the toxicity 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 1.3Ah LiFePO 4 /graphite pouch cells under fire conditions and in using the state-of-the-art fire safety international standards for the evaluation of fire toxicity was applied under two different real-scale simulating scenarios. The obtained results reveal that critical thresholds are highly dependent on the nature of the salt, LiPF 6 or LiFSI, and on the cells state of charge. Hence, this approach can help define appropriate fire safety engineering measures for a given technology (different chemistry) or application (fully charged backup batteries or batteries subjected to deep discharge).