Study of the Role of LiNi1/3Mn1/3Co1/3O2/Graphite Li-Ion Pouch Cells Confinement, Electrolyte Composition and Separator Coating on Thermal Runaway and Off-Gas Toxicity

Abstract : A reliable heating device coupled with a FTIR gas analyzer has been tailored with the aim of evaluating the role of state-of-the-art lithium-ion battery components and environmental conditions on thermal and toxic hazards. Here, we demonstrate its effectiveness in accurately assessing the role of fully charged 0.6 Ah pouch cells confinement, electrolyte composition and separator coating on heat release and toxic gas generation-related risks. The fire safety international standards developed by the ISO TC92 SC3 subcommittee were used to determine the asphyxiant and irritant gases toxicity. Cells tighting confinement proves to be a very efficient way to diminish and delay (from 180 to 245 degrees C) the thermal runaway phenomenon occurrence and relating toxic gas release. Vinylene carbonate as electrolyte additive is able to shift (+20 degrees C) the onset temperature, while substitution of 1/3 M LiPF6 by LiFSI does not modify the thermal behavior, nor the toxic risks. The coating of a tri-layer separator influences the irritant gas toxicity related risk, by decreasing fluorinated components release. This study highlights that some improvements regarding LIB safety can be achieved through appropriate component selection and cells integration design at a module/pack level.