Discrete element method (DEM) analysis of lithium ion battery electrode structures from X-ray tomography-the effect of calendering conditions

Calendering is an essential process step to manufacture electrodes for lithium-ion batteries. The relationship between the various component material properties and calendering conditions has a large impact on the battery performance. In this work, Discrete Element Method (DEM) was used to investigate the electrode structure evolution under different calendering conditions. The initial positions of active material (AM) particles were obtained from an uncalendered electrode microstructure characterised experimentally by X-ray tomography and then imported to DEM simulations. Simulated structures under different processing conditions were obtained by compression tests in DEM. The Edinburgh elasto-plastic adhesive (EEPA) model and bond model were used to describe the mechanical response of AM particles and binder phase during compression. Detailed stress and structural evolutions at microscopic scale were further analysed. For the first time, the results demonstrate a promising way to predict and design battery electrode structures by combining X-ray tomography and DEM analysis.