Dry electrodes faster - make batteries cheaper

Project EPIC aims at energetic, economical and ecological optimization of production

Manufacture of electrodes for lithium-ion batteries: The active material is applied as a paste and then dried. (Photo: Ralf Diehm, KIT)

Manufacture of electrodes for lithium-ion batteries: The active material is applied as a paste and then dried. (Photo: Ralf Diehm, KIT)

With the expansion of electromobility, the demand for suitable batteries is increasing. The aim of the new EPIC project coordinated at the Karlsruhe Institute of Technology (KIT) is to dry high-quality electrodes for lithium-ion batteries faster and more energy-efficiently and thus to manufacture them more cost-effectively. Innovative drying management in electrode production lowers the costs of battery production, improves the environmental balance and strengthens Germany as a business location. The Federal Ministry of Research is funding EPIC with three million euros. 

In battery cells based on lithium ions, for example for future electric cars, the electrode layers are crucial: These active materials store the energy. Both the anode and the cathode material are applied as a water- or solvent-based paste in a thin layer to a conductor foil made of copper and aluminum. The manufacture of the electrodes takes a lot of time and drives up investment and production costs. At KIT, a team of researchers from the Thin Film Technology (TFT) group has developed an innovative coating process with which electrodes for lithium-ion batteries can be produced in the laboratory faster than ever before. The following process steps, i.e. drying with structure formation and post-drying, are currently still a bottleneck, which prevents the increase in the throughput speed of the entire electrode production. “However, it is precisely this area that allows significant cost savings in battery cell production,” explain the TFT researchers. 

Process steps considered interrelated

The aim of the project “Increase the throughput rate in electrode production through innovative drying management”, or EPIC for short, is aimed at reducing battery production costs overall and, in particular, lowering energy costs for electrode drying by at least 20 percent. Here, scientists are working on increasing the drying speed by at least 50 percent. It is important to maintain or even further improve the quality and long-term stability of the electrodes. “It is essential to consider the individual process steps in a coherent way and to take interactions into account,” emphasizes Professor Wilhelm Schabel. The TFT group at KIT, which he leads, coordinates the project. Also involved in EPIC are Professor Jürgen Fleischer from the wbk Institute for Production Technology at KIT and researchers at the Center for Solar Energy and Hydrogen Research Baden-Württemberg (ZSW) in Ulm and at the Technical University of Braunschweig. The Federal Ministry of Education and Research (BMBF) is funding EPIC as part of the ProZell II research cluster for three years with a total of three million euros. The project started in August 2020. 

The EPIC project is not only about innovative drying and post-drying technologies that combine energy efficiency and high quality, but also about moisture management that is optimally tailored to the materials along the process chain - from drying to cell assembly. The TFT group at KIT deals with conventional drying processes and the use of high-performance emitters, as well as with the entire drying management. "Higher coating speeds are particularly attractive if the drying time can be shortened at the same time so that the expensive drying section does not have to be extended," explains Dr. Philip Scharfer from TFT. 

The wbk of KIT examines both the post-drying directly in the cell stack before the electrolyte filling and the setting of the required cell moisture without prior post-drying in the cell stack directly before the electrolyte filling. In all cases, the wbk, together with the Technical University of Braunschweig, evaluates how drying intensity and duration influence the cell properties. The ZSW in Ulm will use its research production line, on which battery cells can be manufactured on an industrial scale, to map the moisture exposure under a regulated production atmosphere on a scale comparable to that of series cell production. 

Networking strengthens battery research

The project partners evaluate the various production approaches using suitable process-cost models and give recommendations for action for transferring them to an industrial production process. In addition to energy and resource efficiency and battery cell quality, they also include the environmental compatibility of the various approaches. The TFT group develops its electrode production technologies - also for future new material systems - in the Center for Electrochemical Energy Storage Ulm & Karlsruhe (CELEST), one of the world's largest battery research platforms. New findings on production technology also flow directly into the Post Lithium Storage Excellence Cluster (POLiS), in which KIT is developing the batteries of the future together with Ulm University and the ZSW. 

More about Karlsruhe Institute of Technology

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KIT is one of the biggest research and education institutions worldwide and has the potential of reaching a top position in selected research areas on an international level. The objective is to turn KIT into an institution of top research, excellent scientific education, and a prominent location ... learn more

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