Study of graphite/NCA Li-ion cell degradation during accelerated aging tests — Data analysis of the SIMSTOCK project

This paper presents a preliminary analysis of aging data from the French SIMSTOCK program in order to evaluate the influence of several aging factors on capacity fade and impedance increase of graphite/NCA Li-ion batteries over accelerated aging tests. Test protocols (cycling and check-up) are presented, and the behavior of battery under aging is described. An equivalent-circuit model is used to extract the various contributions of the impedance spectra. Finally, the influence of the aging factors on capacity fade and impedance increase is discussed.