Development of structure integrated supercapacitors as functional layer

Abstract

The demand of highly efficient electrical power supply is one of the most crucial requirements for new development in aircraft and space development. All electric flight or eVTOLs suffer from low performance due to high weight and comparatively low available energy. A lot of battery research is currently ongoing. However, due to the chemical storage processes a battery’s lifetime is significantly limited to typically 5000-10000 cycles. In contrast, supercapacitors use physical processes for energy storage which are mostly reversible allowing more than 1 million cycles. Due to their stabile performance they can be considered as maintenance free, ideal for the integration within composite structures. This combination of structural and energy functions offers a great opportunity to save weight and volume. Beside their application in aircrafts this approach is of high interest for space applications. In the presented approach pouch-like supercapacitors are integrated into fiber reinforced plastics composites using autoclave processing. The supercapacitors are manufactured using two aluminum collectors coated with a layer of 140µm activated carbon, supplied by UniverCell. The electrodes are saturated with an ionic liquid (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide) supplied by IoLiTec. The electrodes are separated by a porous insulation film (Celgard 3501). The aim is to reach high specific power density AND high mechanical stiffness. Intensive electro-mechanical characterizations are conducted. Polymeric electrolytes materials are also analyzed for further reduction of parasitic masses. Finally, the laboratory tests are upscaled to build a full-scale demonstrator to proof the concept.