A strong demand on simultaneous increases in energy and power densities, as well as a prolonged lifetime, and increased safety of batteries at low battery costs, calls for virtual prototyping with predictive models in the early development phase. To present significant progress in the area of advanced continuum Li-ion battery models this paper presents: a) an innovative continuum modelling framework that more consistently reproduces real multi-particle size distributions and electrode topology, b) the application of thermodynamically based potential as a function of active particle lithiation in the model of the entire cell, c) consistent integration of performance and degradation models of SEI formation.
The capabilities of the modelling framework were validated on LiFePO4. The presented results clearly indicate that the proposed modelling framework features more adequate modelling representation at the level of continuum battery models. This is confirmed by the high relevance of modelled voltage vs. capacity results for low and high discharge rates and the simultaneous high relevance of interparticle transport phenomena, which are in agreement with recent nanoscopic findings. Furthermore, the presented results also confirm that the proposed modelling framework is capable of simulating degradation phenomena and thus enables adequate virtual representation of battery parameters of degraded batteries. These innovative functionalities allow – compared to the current state of the art – for a more efficient and systematic model supported design of battery based energy systems.
Keywords Li-ion battery, continuum modelling, innovative ion wiring, LiFePO4, thermodynamically based particle potential, degradation modelling