Scaling of ultrashort-pulsed laser structuring processes for electromobility applications using a spatial light modulator

Abstract

The structuring of lithium-ion battery (LIB) electrodes and the diffusion media (DM) for polymer electrolyte membrane fuel cells (PEMFCs) with ultrashort laser pulses enables improved performance characteristics of both technologies. However, the transfer of the approaches from a laboratory scale to a commercial use has previously been hindered by the low average output power of ultrashort-pulsed (USP) laser beam sources and the limited productivity of single-beam structuring using scanning optics. Recent advancements in the development of USP laser systems have led to a steady increase in the available output power, thereby enabling new fields of applications. This study aims at accelerating the USP laser structuring of LIB electrodes and DM for PEMFCs to industrially relevant processing rates by comparing a single-beam with a multibeam structuring process regarding ablation characteristics and quality. For the multibeam strategy, the shape of the laser beam was modified by a spatial light modulator (SLM). In addition to microholes, the insertion of microchannels was investigated to demonstrate the high flexibility of state-of-the-art SLMs. The geometry of the created structures was measured with a laser scanning microscope, and the different layers were tested for their geometrical and electrochemical properties to compare both technologies. The results confirmed that applying an SLM enables high-quality microstructures with significantly higher structuring rates. Furthermore, this contribution includes a theoretical analysis of the specifications required for a laser setup to reach an industrially relevant productivity of the structuring processes.