CleanSky2 SOLIFLY - Developing structural batteries towards aeronautic application

Radical innovations for all aircraft systems and subsystems are needed for realizing future carbon neutral aircraft, with Hybrid Electric Aircraft (HEA) to be delivered after 2035, at first in the regional aircraft segment. Electrical energy storage is one key element here, demanding safe, energy dense, lightweight technologies. Combining load bearing with energy storage capabilities is a promising way to minimise the detrimental impact of battery weight on the aircraft. However, despite the various concepts developed in recent years, the viability of this solution has been demonstrated at material or coupon level only, leaving many open questions concerning its effective applicability for structural elements of a size relevant to the effective implementation into the airframe.

Within the CleanSky2 project SOLIFLY “Semi-SOlid-state LI-ion Batteries FunctionalLY Integrated in Composite Structures for Next Generation Hybrid Electric Airliners” (2021-2023) the AIT Austrian Institute of Technology, the aeronautics research centers ONERA and CIRA, the Universities of Vienna and Naples, and the SME CUSTOMCELLS Itzehoe, will be conducting research to develop further structural batteries towards aeronautic applications.

Based on a non-conventional semi-solid-state formulation suitable for Li-ion structural batteries, two different scalable battery cell concepts are to be developed further and combined: on the one hand, so-called Coated Carbon Fibres (CCF/carbon fibres coated with active material), which intrinsically store energy, and, on the other hand, thin battery cells that are installed into the carbon composite structure (Reinforced Multilayer Stack/RMS). Functional integration of the formulation will be optimized, first at the cell level and subsequently scaling up the cell concepts, on a representative aerospace-grade component, here a stiffened panel, to demonstrate the electrochemical and mechanical properties of the developed structural battery technology.

A further aspect that SOLIFLY focuses on is to closely link technological development to the actual needs of the aviation industry. To ensure this, the expectations and specifications of the aircraft manufacturers are incorporated into the design process from the very beginning, taking into account airworthiness and production requirements. A technology roadmap and a technology readiness level scale-up strategy are project outcomes which ensure that the inherently scalable processes can actually be industrialized.

The talk will present the concept of SOLIFLY, the progress achieved in the first phase of the project including the outcome of a first industrial workshop.