Conventional energy storage systems such as batteries have disadvantages in terms of mass, space requirements and sustainability. For aircraft in particular, mass is one of the most important factors, and this can be reduced by integrating energy storage systems into the structures.
In the first phase of the SE2A cluster basic materials were developed that have the potential to be used as power composites. Both a lithium pouch cell was integrated into a composite structure as an intermediate layer and a high-strength structural electrolyte was created by embedding sodium-based polymer electrolytes in glass fibres. A specific energy density of 64-120 Wh/kg was achieved with lithium-based electrolytes, while a specific energy density of 23 Wh/kg was achieved with sodium-based electrolytes.
The current phase of the project is investigating different integration routes, focusing on feasibility, weight reduction and maximum energy storage capacity. Primary structures are highly stressed, while secondary structures are minimally stressed. This is advantageous for the integration of efficient electrical energy storage because the ability to transfer mechanical loads and ion mobility behave in opposite ways. In addition, interchangeability, impact behaviour and the influence of moisture will be investigated. The development of an electrode based on conventional carbon fibre semi-finished products will be considered as well as the development of a conventional battery electrode applied to the surface of carbon fibres. Once an integration route has been selected, small scale model prototypes will be constructed. These prototypes will then be mechanically and electrically tested using a realistic load scenario. Finally, a demonstrator will be built.
