Batteries' end of life: Modeling the ageing phenomena distinguishing linear and nonlinear phases

As the energy transition manifests itself a little more everyday and as the public wishes to see more renewable energy sources harnessed and incorporated into the energy grid, the need for storage becomes always more necessary. This is particularly true in the field of electricity, where electrochemical batteries play a predominant role for well over a decade now. Omnipresent in mobile devices, lithium-ion batteries are now envisioned for stationary storage projects. To accurately evaluate the economic potential of such projects, a good understanding of the battery lifetime is needed. In coherence with recent academical publications, this study proposes the elaboration of an ageing model for a lithium-ion battery made of a graphite anode and an LFP cathode, evidencing linear and nonlinear ageing phases. Focusing on two ageing mechanisms corresponding to such ageing phases, SEI formation at the anode and lithium plating, this P2D model aims at accurately forecast the lifetime of a Li-ion battery through several use cycles. The P2D model is implemented in the Comsol Multiphysics software using the lithium-ion batteries module. Cycling data obtained from trials conducted at EDF R&D are used for model calibration and validation.