An empirical degradation model for Li-ion batteries and its extension into second-life applications
Jinsong Hua, Preben J. S. Vie and Julia Wind
Institute for Energy Technology (IFE)
Lithium-ion batteries suffer from degradation caused by their operational conditions and consequently have a limited lifetime within their first application. These batteries might be available for re-use in a different application, commonly under more moderate usage conditions. The influence of such a change in operating conditions on battery degradation within a second life application is not very well understood.
Here we present the parameterization and subsequent extension of an empirical degradation model that formulates the degradation process as a function of battery operations for both, first- and second life applications. We focus on a commercial 64 Ah NMC-graphite pouch cell. The model parametrization is based on a large dataset containing both calendar and cycle life data of more than 100 cells, covering a large window of temperatures (5-45 °C), C-rates (0.2-1.5 C), SoC windows, and average SoC.