High-Speed Laser Drying of Lithium-Ion Battery Electrodes – Experimental Analysis of Binder Migration Effects

Convection drying of battery electrodes for lithium-ion batteries is currently the most energy-intensive process step in battery production due to the low energy efficiency of state-of-the-art convection dryers. Laser-based drying is considered a particularly promising alternative due to the homogeneous and easily controllable energy input using a VCSEL or diode laser. It has already been shown that despite the significantly increased drying rates in hybrid laser and convection-based two-stage drying processes, no negative effects on the quality characteristics of LFP cathodes are to be expected. In the stand-alone laser drying process with significantly reduced drying times, there is a risk of adhesion loss due to binder migration. As part of an experimental study, the effects of high-speed laser drying on electrode quality were investigated in terms of adhesion and SEM/EDX analyses. It was shown that a loss of adhesion due to binder migration can occur in the single-stage laser drying process, particularly at high layer thicknesses and laser intensities. At lower layer thicknesses, no negative influences on the electrode quality could be determined in stand-alone laser drying processes for LFP cathodes.