Comprehensive Battery Safety Risk Evaluation: Aged Cells versus Fresh Cells Upon Mechanical Abusive Loadings

摘要

Despite their wide applications, lithium-ion batteries (LIBs) have beenstruggling with their safety risks arising from different lifetime stages. Here,the NCMA pouch cell is taken as an example, and the safety of both fresh andaged cells from three milestone stages, that is, internal short circuit (ISC)triggering risk, ISC mode, and the subsequent thermal runaway (TR)consequence is investigated. By combining mechanical abusive testing andphysics-based models on commercialized cells with various states-of-health(SOH) and states-of-charge, it is discovered that the ISC triggering delays withthe decay of SOH and soft ISC mode will be triggered more frequently, whichis mainly due to the mechanical behaviors of the current collectors. Thetemperature rises and peak temperature during the subsequent TR alsobecome milder for aged cells due to the reduced capacity and deterministicsoft ISC process. Results here provide a mechanistic explanation of the safetyrisk comparison between the fresh and aged cells, offering cornerstoneguidance to the evaluation and design of next-generation safer LIBs.