Simulation of the Calendering Process of NMC-622 Cathodes for Lithium-Ion Batteries

Calendering is the final step in electrode production during the manufacturing of lithium-ion batteries. It is a crucial process that significantly influences the electrodes’ mechanical and electrochemical properties and is decisive in defining their volumetric energy density and performance. Herein, a discrete element method modeling approach is proposed to predict the process parameters of the calendering process. In particular, the roll gap width is required for a given target porosity. For this purpose, a particle bed of 9 mm in length is compacted using a roll section enabling a deeper look into the compaction behavior of the microstructure. Six NMC-622 electrodes with different thicknesses are produced and compacted to different porosities. In the experimental investigation, the roll gap width is set and measured allowing a simulative replica of the process. With the process simulation, the force propagation within the electrode can be observed on a particle level. Furthermore, nanoindentation measurements with NMC-622 cathodes provide information on the densification behavior of cathodes and support the parameterization of the particle bed. The particle-based simulation of the compaction process is experimentally validated using nanoindentation measurements on NMC-622 cathodes.