STRUCTURAL INTEGRATED SUPERCAPACITORS

Abstract

The latest developments in all-electric flying either of short-range fixed wings or very short take-off and landing (VTOL) vehicles suffer from the low performance of current available battery technology. Therefore, conventional power supplies such as gasoline or alternative power systems using hydrogen, synthetic fuels and gas turbines are favorized for realization in the next generation aircrafts. Additionally, more and more electrical applications are used within the aircraft. One environmentally driven scientific focus is research on more powerful batteries. However, due to the chemical storage processes their lifetime is limited to 5000-10000 cycles. In contrast, supercapacitors primarily use physical processes for energy storage. These processes are reversible. As result more than 1 million cycles are possible, so that the supercapacitor can be considered as maintenance free. They are ideally suited to being combined with a fiber composite structure. The combination of structure and energy storage results in great opportunities to save weight and volume. Due to high costs this approach is especially interesting for aerospace applications. The presented approach consists mainly on the integration of a pouch-like supercapacitor component, which is integrated into the lay-up of a fiber reinforced plastic composite using autoclave processing. The supercapacitors are manufactured using two aluminum collectors coated with a layer of 140µm activated carbon, a separator film and an ionic liquid. The aim is to reach high specific power density AND high mechanical stiffness. The whole setup is intensively electro-mechanical characterized. Still there are challenges of minimizing parasitic masses, improving the specific energy and improving the durability. This approach is realized in laboratory scale but also in several full-scale demonstrators successfully tested for space qualification.