Accelerated electrode drying for cheaper battery production

The newly launched EPIC project, coordinated by the Karlsruhe Institute of Technology (KIT), aims to accelerate the drying of high-quality electrodes for lithium-ion batteries, increasing the energy efficiency of this process and hence reducing the cost of production.

The quality of battery cells based on lithium ions for future electric cars, for instance, decisively depends on the electrode layers — the active materials that store the energy. Both the anode and the cathode material are applied in a very thin layer of a water- or solvent-based paste onto a conducting foil made of copper and aluminium, respectively.

Production of electrodes takes a long time and increases investment and production costs. Researchers from KIT’s Thin Film Technology (TFT) group have now developed an innovative coating process in which electrodes for lithium-ion batteries can be produced in the lab faster than ever before, reducing costs in the process.

The aim of the EPIC project is to reduce overall battery production costs and in particular the energy costs for electrode drying by at least 20%. The scientists are working on increasing the drying speed by at least 50%, while maintaining or even further enhancing quality and long-term stability of the electrodes.

EPIC is funded by Germany’s Federal Ministry of Education and Research (BMBF) with a total of €3 million for a duration of three years. Other project partners include Professor Jürgen Fleischer from KIT’s wbk Institute of Production Science and researchers from the Center for Solar Energy and Hydrogen Research Baden-Württemberg (ZSW) in Ulm and the Technical University of Braunschweig.

EPIC not only focuses on innovative drying technologies that combine a high energy efficiency with high quality, but also on optimal moisture management for the materials used along the process chain, from drying to cell assembly. TFT is studying conventional drying processes, use of high-power radiators and drying management in general.

“Higher coating speeds are particularly attractive when drying time can be reduced and the expensive drying line does not have to be extended,” said Dr Philip Scharfer from TFT.

wbk researchers, in cooperation with the Technical University of Braunschweig, will evaluate how the drying intensity and duration influence cell properties, trialling methods including drying directly in the cell stack prior to electrolyte filling as well as adjustment of the required cell moisture without prior drying in the cell stack directly before electrolyte filling. ZSW will model on its line for the production of industry-scale batteries the exposure to moisture under a controlled production atmosphere on a scale comparable to that of series production.

The different approaches to production will be evaluated by the project partners using suitable process cost models, then recommendations will be made for transferring the process to the industrial scale. Apart from energy and resource efficiency as well as battery cell quality, environmental compatibility will also be considered. The findings will be incorporated directly in the Post Lithium Storage (POLiS) Cluster of Excellence, in which KIT will develop future batteries together with Ulm University and ZSW.

Image caption: Production of electrodes for lithium-ion batteries: the active material is applied as a paste and then dried. Image credit: Ralf Diehm/KIT.

Please follow us and share on Twitter and Facebook. You can also subscribe for FREE to our weekly newsletter and bimonthly magazine.