Direction-dependent mechanical-electrical-thermal responses of large-format prismatic Li-ion battery under mechanical abuse

Abstract

Excessive external mechanical loadings to Li-Ion battery (LIB) usually induce undesired deformation and fracture, internal short circuit (ISC) onset and irreversible thermal runaway. This paper reports an experimental study on mechanical-electrical-thermal responses of large-format prismatic LIB cells under quasi-static and dynamic mechanical indentation. The prismatic cell behaves differently between out-of-plane and transverse indentation in terms of mechanical-electrical-thermal characteristics. To gain a comprehensive understanding towards the mechanically-induced ISC and the exothermic reactions, internal configurations of the prismatic cells are further examined via X-ray computed tomography. Critical internal ruptures at ISC onset are probed and relative sliding of electrode layers causes short contact. The influences of loading direction on SOC- and rate-dependence of multi-field responses are discussed, and hazardous ISC onset and elevated surface temperature are further evaluated.