Experiment and simulation of the fabrication process of lithium-ion battery cathodes for determining microstructure and mechanical properties

• Published in: Journal of power sources 2016-04, Vol.312 (C), p.172-183
• Main Authors: Forouzan, Mehdi M., Chao, Chien-Wei, Bustamante, Danilo, Mazzeo, Brian A., Wheeler, Dean R.
• Format: Article
• Language: English
• Subjects: Binders; Cathodes; Computer simulation; Electrode elasticity; Li-ion cathode; Lithium-ion batteries; Mathematical models; Microstructure; Microstructure prediction; Parametrization; Particle dynamics simulation; Simulation; Slurry viscosity
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2016.02.014

The fabrication process of Li-ion battery electrodes plays a prominent role in the microstructure and corresponding cell performance. Here, a mesoscale particle dynamics simulation is developed to relate the manufacturing process of a cathode containing Toda NCM-523 active material to physical and structural properties of the dried film. Particle interactions are simulated with shifted-force Lennard-Jones and granular Hertzian functions. LAMMPS, a freely available particle simulator, is used to generate particle trajectories and resulting predicted properties. To make simulations of the full film thickness feasible, the carbon binder domain (CBD) is approximated with μm-scale particles, each representing about 1000 carbon black particles and associated binder. Metrics for model parameterization and validation are measured experimentally and include the following: slurry viscosity, elasticity of the dried film, shrinkage ratio during drying, volume fraction of phases, slurry and dried film densities, and microstructure cross sections. Simulation results are in substantial agreement with experiment, showing that the simulations reasonably reproduce the relevant physics of particle arrangement during fabrication. [Display omitted] •A particle-based simulation of drying process of Li-ion battery electrodes is developed.•The mesoscale simulation explains all particle motions, and forces between particles.•The simulation is validated by multiple experimental tests.•Several mechanical and structural properties of the slurry and dried film are predicted.•The simulation relates fabrication parameters to the microstructure of the electrodes.