Session: 04-04: Integrated Smart Systems

Paper Number: 91201

91201 - Challenges of Upscaling Power Composites for Aerospace Applications 

The latest challenge of powering the entire aircraft electrically demands on the supply and storage of electrical energy. Furthermore, more and more electrical applications are used within the aircraft. A lot of research is currently done about more powerful batteries. However, due to the chemical storage processes their lifetime is limited. In contrast, supercapacitors use reversable physical processes for energy storage. This principle allows more than 1 million cycles an can therefore be  considered as maintance free and ideal for integration within composite structures. This function combination offers a great opportunities of weight and volume savings. Beside their application in aircrafts this approach is due to its lightweight potential very beneficial for space applications.

In the presented publication, pouch supercapacitors are integrated into fiber reinforced plastics composites by autoclave processing. The supercapacitors are manufactured using aluminum collectors coated with 140µm activated carbon, supplied by Skeleton, a separator film (Celgard 3501) and different ionic liquids such as 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide supplied by IoLiTec. The aim is to reach high specific power density and high mechanical stiffness. After intensive electro-mechanical characterization of the multifunctional composite there are challenges of further optimizing the system in terms of reducing parasitic masses, conducting consistent interface engineering such as an ideal saturation of the electrodes by the electrolyte and improved conductivities throughout the whole system. Furthermore, the curing processes must be tuned according to the specific materials and upscaling factors have to be identified and evaluated for a better performance prediction of the full-scale power composite.

In this presentation an electrically and structurally successful integration of supercapacitors within a cubesat solar panel is shown. The whole process from laboratory scale up to the full-scale demonstrator is described. The aim is to outline the differences and challenges between analytical results, simulated models, laboratory scale tests and a full-scale, highly integrated structure, which has to meet all requirements and space certifications, which will be tested on orbit 2023.

It can be shown that it is possible to transfer specific properties from laboratory scale into the full-scale demonstrator but it needs the consideration of the whole system. The electrical and ionic conductivity as well as the electrolyte mass and the integrity of the surrounding composite play decisive roles.

However, although this integration strategy represents no multifunctional monolithic power composite but an integration of a tailored power component. This power composite reaches 80% of the mechanical performance of the neat composite structure combined with the power density and life cycle stability of a commercial supercapacitor. This is as weight and volume effective that more space and aircraft applications are currently pepared for full-scale demonstration in order to be deployed in the future aerospace transport. 

Presenting Author: Sebastian Geier German Aerospace Center