Enabling the electrochemical simulation of Li-ion battery electrodes with anisotropic tortuosity in COMSOL Multiphysics.

Li-ion battery electrodes, such as widely used graphite anodes, may have anisotropic tortuosity due to the non-equiaxed shape of the active material particles and the post-casting calendaring process. Such anisotropy can be ignored in conventional electrodes because all the macroscopic ion transport occurs along the electrode thickness, making the ion transport effectively one dimensional. However, the anisotropy becomes important to consider with three-dimensional architectures, such as those generated by laser-patterning. COMSOL Multiphysics is one of the leading tools used by the Li-ion battery modeling community to simulate the electrochemical dynamics of the Li-ion batteries. However, in its current implementation of the underlying model equations, the Li-ion battery module in COMSOL 5.4 cannot be used to simulate the electrochemical behavior of an electrode with anisotropic tortuosity. In this work, we show how the current implementation can be modified to simulate the anisotropic case.•The existing Li-ion battery model in COMSOL 5.4 was extended to account for the anisotropy in the electrode tortuosity•The extended model is necessary to accurately simulate the electrochemical dynamics of 3D architectures such as •The testing and validation results are included in this work.