Laser Processing of Battery Materials - Process Up-Scaling and Strategies for Tuning of Materials Properties

Laser technologies that are suitable for the production of batteries can be divided into three categories: 1st laser cutting and welding; 2nd laser structuring, modification and annealing; and 3rd laser diagnostics. Laser cutting and welding reached already a high mature level and commercial applications. However, those technologies have in general no significant impact on battery performances. This is completely different for the 2nd category where a substantial improvement of cell lifetime, high rate capability, and gravimetric or volumetric energy density are intended to be reached. Such laser-induced tuning of material properties is mainly due to modified electrode architectures of the composite materials caused by capillary features, free-standing structures, variation in porosity, or increased active surface area. The technology readiness level of 2nd category covers so far basic research, feasibility studies, and technology development on lab scale (TRL 4). High power ultrafast laser structuring of electrodes within the next few years will reach technology demonstration level (TRL 5-7). For this purpose lab-scale laser structuring of nickel-rich lithium nickel manganese cathodes and high energy anode materials is going to be transferred to roll-to-roll processing. In preparation for this technology breakthrough, the development of laser structured nickel-rich NMC electrodes and high energy silicon/graphite anodes with high mass loading will be presented. Hereby, laser structuring is accompanied by the application of new material designs, e.g., the passivation of active material particles prior to laser processing or the passivation of composited electrodes subsequently to laser processing. Laser technologies of 3rd category are quite spread in application for battery manufacturing, e.g., for optical vison systems, thickness and positioning measurements. Lately this category is complemented by laser induced breakdown spectroscopy (LIBS) enabling in-situ coating quality control, supporting coating and electrode architecture development and post-mortem studies for cell degradation analysis. The impact of electrode architecture, coating defects, and mechanical pressure in cell designs on cell performance and degradation processes will be presented.