Scaling effects of fast laser drying processes in battery production

This study investigates the effects of laser drying on the quality of graphite-based lithium-ion battery anodes, using a water-based slurry of graphite, conductive carbon, carboxymethyl cellulose (CMC), and styrene-butadiene rubber (SBR). The slurry was coated onto copper foil using a roll-to-roll slot-die process and dried by either a convection oven or a laser module for comparison. Process parameters such as wet coating thickness (130 μm and 200 μm), web speed (1 m/min and 2 m/min), and drying temperature (70-110 °C) were systematically varied. Residual humidity and adhesion were evaluated using thermogravimetric analysis and adhesion testing, respectively. Results show that laser drying achieves up to 90% of the adhesion values obtained with conventional oven drying for thin coatings (130 μm) in less than half the drying time. Laser-dried electrodes also exhibit lower residual humidity compared to oven-dried benchmarks. However, higher evaporation rates and greater coating thicknesses promote binder migration and reduce adhesion, highlighting the need for precise control of drying parameters. Overall, laser drying demonstrates significant potential for efficient, high quality electrode manufacturing, particularly for thinner coatings.