Understanding the Influences of Laser Perforation on Thick Electrodes for Lithium Ion Batteries Via 3D Microstructure Simulations

Abstract

Laser perforation is a precise technique to decrease ionic diffusion limitations by selectively removing material with spatial precisions of tenth of micrometres. It is mainly applied in thick electrodes to improve foremost rate capability, as well as cycle stability, Li plating detention and wetting efficiency.[1] [2]Mostly, holes are created in the batteries through-direction leading to a material removal of about 5%-10% of the initial load. This removal creates inhomogeneous diffusion channels especially into layers close to the current collector, as opposed to a homogeneous increase in porosity.It is of interest to find an optimal trade-off between the competing factors of capacity loss and increase in ion conductivity due to material ablation. Optimization of structuring parameters requires intimate knowledge of electrode and material properties. However, there is a lack of an adequate description of the inhomogeneous structure and its influence on the electrochemical performance. [1]In our presentation we show a detailed 3D microstructure resolved simulation study, examining the influencing parameters for laser perforation. The data suggests, that perforating holes with small diameter at a short distance, which results in an ablation of ca. 8% gives generally desirable improvements for the rate capability. Laser perforation is distinctively favourable in contrast to a raise in homogenous porosity.Moreover, the microstructure resolved simulation also allows for a detailed analysis of different hole shapes and hole misalignment in electrodes after stacking. We evaluate the impact of different configurations on the electro chemical performance. [3]