• In Milestone 7 of the NEXTCELL project, a multi-scale and multi-physics model has been successfully developed to simulate electrode material performance and degradation.

To address the lack of a virtual tool that efficiently supports the virtual design of NEXTCELL cells, an innovative multi-scale and multi-physics electrode material performance and degradation model has been successfully developed in WP7 ‘Modelling the gellified cell concept.’ And the preliminary positive result of the model is obtained in this step.

The developed model provides in-depth insights into intra-particle phenomena as well as film formation on the surface of electrode materials. These objectives were achieved through the creation of an innovative and consistent multi-scale tool chain that delivers a high level of predictive capability and significantly contributes to the development and optimization of NEXTCELL cells.

The necessary modeling building blocks were created to address challenges specific to NEXTCELL cells: (i) an accurate chemo-mechanical model of silicon lithiation and delithiation, including interfaces with the electrolyte, focusing on performance, aging, and safety, and (ii) the corresponding model for the new cathode.

A model of electrode active particles was successfully developed, forming one of the pillars for achieving high predictive capability. Gibbs free energy density was integrated into this model, which has been applied to real particle geometries to simulate concentration and stress-induced coupled intra-particle transport and surface kinetic phenomena under realistic boundary conditions. This approach focuses on leveraging the chemo-mechanical model of composite silicon to develop a mechanical wear-based model for Solid Electrolyte Interphase (SEI) formation on silicon particles.

At this stage of the project, the development of these models is progressing according to the predicted timeline. Separate models for SEI growth and the chemo-mechanical behavior of secondary electrode particles have been successfully implemented. The coding and testing phases for both models are complete, and they are now in the validation phase. Initial validation has been conducted using data from the literature, demonstrating the functionality of both models.