There is no other transport sector than the aerospace that benefits more from lightweight construction and multifunctionality. Therefore, often composite materials are used to build the load bearing structures. This material offers the potential to integrate new functions within the lay-up. One approach is the integration of supercapacitors (SC) as energy devices for decentered energy supply. Supercapacitors can endure more than a million cycles because they use only physical processes to store energy. Supercapacitors can be considered as almost maintenance-free and therefore they are ideal for being integrated. The combination of energy storage and structural tasks offers a great opportunity of weight and volume savings.This paper deals with the development of thin film supercapacitors which can easily be integrated within layers of a structural laminate. The aim is to provide enough and reliable power for a peak power application. In the presented study a satellite positioning system equipped by high torque wheels (HTW) should be powered by the integrated supercapacitors. The power requirements of the HTW demand 24Volts and 5F. Therefore, 14 supercapacitor films are connected in series. A SC-film is manufactured of two electrodes supplied by Skeleton Technologies, divided by a separator supplied by Celgard. Both, the electrodes and the separator are sufficiently saturated with ionic liquid (IL). Beside small distances of the electrodes and their high specific surface area, the electrochemical window of the ionic liquid is one of the key properties to increase the SC performance. Several ILs are tested within the capacitor set up to check the maximum voltage and their power density. Furthermore, a balanced quantity of IL is important, both for the electrochemical performance and the mechanical stability of the surrounding composite. The mechanical stability of the energy composite is investigated by 4-point-bending tests. The cycle stability of the SC is proven by up to 1 Mio charging and discharging cycles. Finally, the structure integrated SC on laboratory scale must be scaled up to a full scale demonstrator. To reach a technical readiness level of 5 and to be able to join a future satellite mission, all mechanical and electrical functions of the structural integrated energy device have to be verified within a series of space qualification tests.It can be shown that the integrated SC affect the bending modulus only by 10-15% meanwhile their electrochemical signal allows conclusions about their mechanical and thermal conditions. However, in combination with a comparably low degradation of 15-20% within a Mio cycles they reveal to be a robust, powerful and maintenance free energy devices, which are ideal for integration. The full scale demonstrator reaches 70-80% of weight and volume saving in comparison to the separated design of structure and energy supply. Furthermore, all qualifications test were passed successfully. This application reveals the potential of this integration approach.

Robust and Powerful Structural Integrated Thin Film Supercapacitors for Lightweight Space Structures

Paper Proceedings: https://asmedigitalcollection.asme.org/SMASIS/SMASIS2021/volume/85499

ASME 2021 Smart Materials, Adaptive Structures and Intelligent Systems (SMASIS2021)

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.