A Model for Investigating Sources of Li-Ion Battery Electrode Heterogeneity: Part I. Electrode Drying and Calendering Processes

Abstract

Heterogeneity of porous electrodes can cause battery failure and performance deficiencies. On the other hand, some types of heterogeneity can improve performance. This study uses a multi-phase smoothed particle (MPSP) model, derived from smoothed particle hydrodynamics (SPH) and which is parameterized and validated by comparison with experimental viscosity, density, electronic conductivity, MacMullin number, and Young’s modulus of electrode films. The MPSP model simulates all major aspects of electrode production: mixing, coating, drying, and calendering, though the focus in this paper (Part 1) is on drying and calendering. Four types of electrodes are included in this study: a graphite anode and three traditional metal oxide cathodes. The model suggests how some types of heterogeneity can form during cathode and anode fabrication. The anode is more susceptible to mesoscale heterogeneities than the cathode due to differences in active particle shape and stiffness. The model and experiments show that regardless of the active material type, calendering increases the variability in electronic and ionic conductivity due to carbon and binder redistribution. This can be explained by means of the proposed multi-phase packing theory. On the other hand, calendering increases mechanical uniformity as also shown by model and experiment.

Measuring Instruments for Characterization of Intermediate Products in Electrode Manufacturing of Lithium‐Ion Batteries

“…[111] A well-parameterized calendering process positively impacts the adhesion, cohesion strength, and the electrode's homogeneity. [70,112] Other important parameters are the elastic and plastic deformability within the electrode. The deformability can be destructively evaluated using micro-or nanoindention measurements.…”

The ARTISTIC Online Calculator: Exploring the Impact of Lithium‐Ion Battery Electrode Manufacturing Parameters Interactively Through Your Browser

“…Building such a dataset and sharing it with the battery community could be a major help for the development of procedures to consistently validate the electrode microstructures obtained by the models presented here, as well as other computational approaches that start to emerge in the literature. [33][34][35][36][37][38] When and if such data will become available, it would be of interest to establish automatic procedures to link it to the electrode microstructures generated in silico through the calculator presented here. Nevertheless, today the ARTISTIC models, and the associated online platform, should be seen as useful tools to study qualitatively or semi-quantitively the effect of several manufacturing parameters on the 3D electrode microstructure, which we believe can be of particular interest for a deeper understanding of the main trends linking manufacturing, 3D microstructure, and performance.…”

Impact of Electrode Defects on Battery Cell Performance: A Review

“…Nikpour et al. revealed that calendering, typically seen as the measure of choice to reduce heterogeneity of an electrode, can lead to aggregation of active material particles [43] . Although this leads to a locally increased heterogeneity in terms of carbon binder domain distribution as well as electronic and ionic conductivity, the beneficial effects of calendering typically outweigh these inhomogeneities.…”