Comparing Macroscale and Microscale Simulations of Porous Battery Electrodes

Comparing Macroscale and Microscale Simulations of Porous Battery Electrodes

TitleComparing Macroscale and Microscale Simulations of Porous Battery Electrodes
Publication TypeJournal Article
Year of Publication2017
AuthorsKenneth Higa, Shao-Ling Wu, Dilworth Y Parkinson, Yanbao Fu, Steven Ferreira, Vincent S Battaglia, Venkat Srinivasan
JournalJournal of The Electrochemical Society
Volume164
Issue11
PaginationE3473 - E3488
Date Published06/2017
ISSN0013-4651
Abstract

This describes a vertically-integrated exploration of NMC electrode rate limitations, combining experiments with corresponding macroscale (macro-homogeneous) and microscale models. Parameters common to both models were obtained from experiments or based on published results. Positive electrode tortuosity was the sole fitting parameter used in the macroscale model, while the microscale model used no fitting parameters, instead relying on microstructural domains generated from X-ray microtomography of pristine electrode material held under compression while immersed in electrolyte solution (additionally providing novel observations of electrode wetting). Macroscale simulations showed that the capacity decrease observed at higher rates resulted primarily from solution-phase diffusion resistance. This ability to provide such qualitative insights at low computational costs is a strength of macroscale models, made possible by neglecting electrode spatial details. To explore the consequences of such simplification, the corresponding, computationally-expensive microscale model was constructed. This was found to have limitations preventing quantitatively accurate predictions, for reasons that are discussed in the hope of guiding future work. Nevertheless, the microscale simulation results complement those of the macroscale model by providing a reality-check based on microstructural information; in particular, this novel comparison of the two approaches suggests a reexamination of salt diffusivity measurements.

DOI10.1149/2.0501711jes
Short TitleJ. Electrochem. Soc.
Refereed DesignationRefereed