Long Term Aging of Automotive Type Lithium-Ion Cells

Abstract

Long-term cycle aging experiments were performed on commercially available automotive type lithium-ion pouch cells under realistic conditions as found in electrical vehicles. The main mechanisms responsible for cell aging were identified based on a combined approach of electrochemical and post mortem analysis methods, and were attributed to the loss of lithium through lithium metal deposition on the graphite anode and electrolyte decomposition as a side reaction. Furthermore, the aging occurred spatially localized at different rates. Anode material located close to the tabs exhibited most progressed aging, as determined from the rather pronounced local heat generation over a long time period.