Femtosecond Laser Cutting of Current Collectors: A Study for High-Quality Li-Ion Battery Fabrication in Electric Vehicles

The average power of ultrashort laser sources has steadily increased, alongside significant investments by battery companies in advanced technologies, which necessitate solutions to improve ablation efficiency and quality in laser cutting of Li-Ion electrodes. Although burst mode processing has been primarily investigated in micro-processing, its application to cutting remains rarely explored. This paper introduces a simplified efficiency model that provides, with minimal computational cost, rapid insights into process dynamics of femtosecond laser cutting of 8 µm copper and 12 µm aluminum current collectors both in the single pulse and burst mode. The model results are then compared with actual cutting quality under constant conditions of 40 W average laser power and 200 fs pulse length. Results demonstrate that burst mode triples scanning speed, albeit with heat accumulation in aluminum, while MHz processing enables scalpel-like cuts in copper with a kerf half the spot size.