The “hydrogen division” of Graebener Maschinentechnik GmbH & Co. KG, based in Netphen in the Siegerland region, has now announced that it is participating as a subcontractor in the publicly funded BeHyPSy research project (air-cooled fuel cell system for the aviation sector with a particular focus on lightweight system design). Together with ZBT (Zentrum für Brennstoffzellentechnik GmbH) and other partners, the goal is to create a technological milestone for the aviation of the future.

Lightweight, air-cooled fuel cell systems

High-power fuel cell systems have traditionally relied on liquid cooling—a reliable but comparatively heavy system. For unmanned aerial vehicles (UAVs) and light aircraft, however, every gram counts. This is precisely where BeHyPSy comes in: ZBT and its project partners are developing a particularly lightweight, air-cooled fuel cell system specifically for unmanned aerial vehicles and aircraft with takeoff weights ranging from 25 to 2,000 kilograms. According to the ZBT, the goal is “the development, integration, and testing of an innovative propulsion system” that not only offers high performance but can also be scaled for future use in other aviation applications. This would open up significant market potential for sustainable aviation propulsion systems. The technological features of the project essentially encompass two aspects: First, air cooling instead of liquid cooling—this paradigm shift means that the fuel cell system significantly reduces weight and installation space without liquid cooling. The demands on air management increase accordingly—a central development focus of the consortium. The second aspect is a multiphase electric motor for maximum reliability: A multiphase electric motor is powered by a multi-stack fuel cell system. This increases the reliability and availability of the entire system.

Manufacturing of ultra-lightweight metal bipolar plates

As a long-standing mechanical engineering firm and specialist in hydroforming and metal forming processes, the Siegerland-based company supports ZBT as a supplier within the scope of the project. Specifically, the company manufactures the bipolar plates required for the air-cooled fuel cell stacks from thin titanium foils in the Graebener production laboratory. The services cover the entire process chain from coil to finished bipolar plate: forming the metal foils using hydroforming processes, laser cutting, laser welding, and straightening the welded plates. In addition, Graebener supports the development process with engineering services. In close collaboration with ZBT, the company analyzes the technical feasibility limits of the innovative design and evaluates the extent to which process-reliable and batch-consistent manufacturing can be reliably ensured. In doing so, Graebener is making an important contribution to the targeted lightweight fuel cell technology—an area in which the Siegerland-based company can optimally leverage its more than 20 years of experience in the manufacture of metallic bipolar plates.