Laser Processing of Electrode Materials – Concepts for high power / high energy lithium-ion cells

Thick film electrodes in lithium-ion cells are complex multi-material systems with defined material components, grain sizes, porosities, and pore size distributions in the micrometer and sub-micrometer ranges. The development of three-dimensional (3D) cell architectures for electrodes in lithium-ion batteries is one promising approach to overcome limitations in lithium-ion diffusion kinetics, high interelectrode ohmic resistances, and mechanical stresses due to high volume changes during battery operation. 3D battery architectures can realize large areal energy capacities while maintaining high power densities at the same time.
Laser materials processing in manufacturing of Li-ion batteries is a rather new technological approach which enables rapid manufacturing, high reliability, and a reduction of production costs. Laser cutting and welding processes for batteries are already available for advanced industrial production. Laser micro-structuring of battery materials has a huge impact on battery performance and an up-scaling for industrial production is investigated. Advanced laser generated 3D surface architectures in battery materials improve Li-ion diffusion kinetics. ... mehrThis design concept can be applied for thin film micro-batteries as well as for high power thick film Li-ion batteries. Due to optimized laser processing a significant improvement of electrode wetting with liquid electrolyte can be achieved. Both, the improvement in Li-ion diffusion kinetics and the turn of battery materials into superwicking deliver advanced battery performances. Electrochemcial analysis showed that a steep rise of capacity retention at high charging and discharging currents and an improved cell lifetime can be obtained in comparison to standard cells with unstructured battery materials. Post-mortem analysis of electrodes could be successfully applied over large areas and depths by laser-induced breakdown spectroscopy (LIBS) and it could be shown that 3D architectures act as an attractor for lithium-ions and a boost of battery performance can be achieved.