Laser structuring of electrodes in roll-to-roll environment using multi-beam processing: process upscaling and its perspective

The development of next-generation lithium-ion batteries with volumetric energy densities >750 Wh/L and gravimetric energy densities >400 Wh/kg is a key objective of the European Union’s Strategic Energy Technology Plan to be achieved by 2030. Both new materials and production strategies play an important role in the development of those batteries. Thick-film electrodes are advantageous to increase the volumetric and gravimetric energy densities alike since the amount of inactive material can be reduced. To facilitate higher C-rates during (dis-)charging in thick-film electrodes, laser generated structured are introduced, thus creating new lithium-ion diffusion pathways leading to a reduced cell polarization. Additionally, electrode wetting with liquid electrolyte is significantly improved, reducing the risk of dry spots in the electrode stack. Industry interest in implementing laser patterning of electrodes into existing or planned manufacturing lines has increased significantly in recent times. The strip speeds of electrode production are decisive for the required speeds to be realized in laser structuring. Various technical approaches can be applied to upscale the laser patterning process such as multibeam processing which can be realized by splitting a laser beam into several beamlets with a DOE. In this work, a large field scanner and a related optical lens system are combined with an ultrashort pulsed, high repetition rate, high power laser source. The ablation behavior of commercial graphite composite electrode material was investigated for upscaling using different laser patterning scenarios.