Laser materials processing and analytics in battery manufacturing – new design concepts and materials

Lithium-ion batteries suffer so far from high production costs, restricted process reliability, small energy and power density, and short operational lifetime. In order to overcome these drawbacks, laser materials processing is introduced in battery manufacturing in combination with advanced design rules and new electrode materials. Laser patterning of metallic current collectors and active material of thick film electrodes by laser-induced periodical surface structures (LIPSS) and direct laser ablation, respectively, is a research approach for the realization of three-dimensional (3D) electrode architectures that includes the ability of process up-scale and transfer of the 3D battery concept to lithium-ion cells with high energy and power. 3D electrode configurations result in improved high current capability of the cells compared to cells with conventional 2D electrodes due to increased active surface area, reduced mechanical stress during electrochemical charge/discharge cycles, and overall decreased cell impedance. Furthermore, laser generated micro-capillary structures turn composite electrodes into superwicking leading to a rapid and homogenous wetting with liquid electrolyte. ... mehrThis has a strong impact on battery lifetime and product homogeneity. The material and design concept is pushed beyond state-of-the-art by introducing high film thicknesses, and high energy materials such as nickel-enriched NMC cathodes and silicon/carbon anodes. Post mortem analysis by laser-induced breakdown spectroscopy (LIBS) was discovered as a versatile tool for optimizing coating processes and 3D electrode design concept. Binder distribution and lithium mapping along the whole electrode can be visualized. Laser generated 3D architectures act as an attractor for lithium-ions and boost the battery performance at high charging/discharging rate. A variation in porosity in thick film composite electrodes was identified as one of the main driving factors for cell degradation proving that structuring of electrodes by laser ablation cannot be replaced by embossing or structured rolls during calendering process.