LAUSR

A physical-chemical model is suggested, which is able to describe the enhanced discharge rate capability of lithium-ion cells by using laser-structured graphite anodes. Recently published test data of coin cells comprising unstructured and structured graphite anodes with LiNi1/3Co1/3Mn1/3O2 cathodes is used for the presented purpose of modeling, simulation and validation. To minimize computational demand, a homogenized three-dimensional model of a representative hole structure is developed, accounting for charge and mass transport throughout the cell layers and one-dimensional diffusion within radial-symmetric particles. First, a standard pseudo-two-dimensional model is calibrated against rate capability test data of coin cells with unstructured anodes. The calibrated parameter set is transferred to the three-dimensional model in order to simulate the transient voltage response and the discharged capacity depending on the applied C-rate. The simulation data shows excellent agreement with experimental data for both cell types. Three stages of rate capability enhancement are identified showing an improved relative capacity retention of 11−24% at 3C. Experimental and simulation data reveal a restricted C-rate window, which can be positively affected by the structuring process, whereas both shape and pattern of the structuring process can be further optimized with the model. © The Author(s) 2018. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited. [DOI: 10.1149/2.1181807jes]