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.