A new electrode design developed at Fraunhofer ISE raises battery cell energy density by 10 to 15 percent at the same weight, achieved by more than tripling the standard electrode coating thickness from 100 to up to 800 micrometers and cutting the number of current collectors. The architecture was validated in lithium-ion, zinc-ion and sodium-ion cells, and lithium-ion pouch prototypes were built on a semi-automated line in the cleanroom of the Fraunhofer ISE Battery Materials and Cell Production Lab.
Snapshot
Company - Fraunhofer Institute for Solar Energy Systems ISE (Fraunhofer ISE).
Industry partners - Helmut Hechinger GmbH & Co. KG and acp systems AG.
Research partners - University of Stuttgart’s ipv and KIT/Helmholtz Institute Ulm.
Technology - Thick-film electrodes up to 800 micrometers thick, fewer current collectors.
Performance gain - 10 to 15 percent more energy density at the same weight.
Chemistries - Lithium-ion, zinc-ion and sodium-ion cells validated.
Development stage - Lab validation done, pouch prototypes built.
Funding - BMWE for VORAN and INFAB, BMBF for WinZIB2.
The new electrode and cell design developed by Fraunhofer ISE increases battery energy density by 10% to 15% without adding weight. This improvement was achieved by more than tripling the standard coating thickness of battery electrodes from 100 micrometers to up to 800 micrometers, which simultaneously reduces the number of current collectors required in the cell. The research team implemented this new electrode architecture in lithium-ion pouch cells manufactured using industry-standard processes and successfully applied the concept to zinc-ion and sodium-ion battery cells as well.
Dr. Oliver Fitz, group leader for battery cell technology at Fraunhofer ISE, explained that normally the anode and cathode consist of many thin, alternating layers of electrode coating and current collectors. By increasing the thickness of the electrode coating from 100 to up to 800 micrometers, the team created much more space for active material, thereby significantly increasing energy density depending on the battery type and design. The research team initially validated the new electrode architecture experimentally using small battery cells in the laboratory for lithium-ion, zinc-ion, and sodium-ion batteries. For lithium-ion batteries specifically, they also manufactured prototypes of pouch battery cells with the newly developed electrode structure on a semi-automated production line in the modern cleanroom of the Fraunhofer ISE Battery Materials and Cell Production Lab.
The battery electrodes are PFAS-free and are manufactured without the use of toxic solvents. The new cell architecture was developed with future mass production in mind, as a potential electrode production line exhibits significantly lower process complexity compared to a state-of-the-art wet-coating system. As a result, capital costs are significantly lower, and operating costs are also reduced due to lower space and energy requirements. This technology thus opens up the possibility, particularly for small and medium-sized enterprises, to establish their own battery cell production facilities in Germany. The project results demonstrate a promising approach toward the future industrialization of this novel electrode and cell architecture. Helmut Hechinger GmbH & Co. KG is supporting the research consortium as an industry partner and contributing its manufacturing expertise. The machinery manufacturer acp systems AG - also a project partner - is developing the equipment for manufacturing the electrodes.
Markus Duffner, CEO of Hechinger, stated that having started out as a traditional automotive supplier, his company has long been diversifying into future-oriented markets, products, and industries. For example, they already generate over 30% of their revenue in the field of e-mobility. If the next steps in scaling up and validation show promising prospects in terms of both cost and performance, Hechinger could explore industrialization. They see great potential in Baden-Württemberg for battery production focused on stationary storage. Prof. Dr. Andreas Bett, director of Fraunhofer ISE, noted that in a climate-neutral energy system with fluctuating energy sources like solar and wind, stationary battery storage is an integral component for covering morning and evening electricity peaks. He added that Germany would be well advised to build up manufacturing capacity to meet the growing demand for batteries and thereby create value within the country.
Dr.-Ing. Daniel Biro, head of the Electrical Energy Storage Department at Fraunhofer ISE, stated that this technology is the result of many years of research at the institute. He noted they owe their success in reaching this developmental milestone in part to funding from the Federal Ministry for Economic Affairs and Energy (BMWE), the Federal Ministry of Research, Technology and Space (BMFTR) and the Baden-Württemberg Ministry of Economic Affairs, as well as to the trusting collaboration with their partners. The research team developed the new electrode and cell design as part of the projects "VORAN – Innovative Sodium-Ion Battery Storage for Stationary and Mobile Applications" (running through June 2027), "INFAB – Zinc-Ion Batteries for Stationary Energy Storage – Manufacturing and Assembly" (completed), and "WinZIB2 – Globally Deployable, Innovative Zinc-Ion Battery System" (completed). These projects were carried out in collaboration with the partners acp systems AG, Helmut Hechinger GmbH & Co. KG, the University of Stuttgart's Institute for Photovoltaics (ipv), and the Karlsruhe Institute of Technology/Helmholtz Institute Ulm. The Federal Ministry for Economic Affairs and Energy (BMWE) funded the research in the VORAN and INFAB projects, while the Federal Ministry of Education and Research (BMBF) funded the WinZIB2 project.