EEdeL

Motivation

The electrification of aviation represents a major milestone toward environmentally sustainable air transportion. However, conventional lithium-ion batteries are reaching the limits of their specific energy. This is where the EEdeL collaborative research project comes in: by utilizing innovative sulfide-based solid-state battery cells, the specific energy can be doubled to more than 500 Wh/kg – a breakthrough for electric flight applications.

For stable operation, solid-state batteries require external pressure exceeding 5 MPa. To date, this pressure has typically been provided by mechanical metal-based structures, which are heavy and largely negate the weight advantage offered by the cells themselves. The core motivation of EEdeL is to resolve this trade-off. By employing weight-optimized carbon fiber reinforced polymer (CFRP) composite materials, a comparatively lightweight pressure application system can be realized.

Objectives and Approach

The primary objective of the EEdeL project is the design, testing, and manufacturing of a pressure-resistant lightweight composite structure for efficient pressure application. Fraunhofer IWS plays a key role in the project and is responsible for the development and production of sulfide-based solid-state prototype cells based on its own patented cell concepts.

In addition, Fraunhofer IWS is establishing uniaxial and isostatic laboratory pressure test devices operating in a pressure range from 1 to 25 MPa. Using these test bed, researchers will determine the optimal temperature- and pressure-dependent operating parameters of the cells. These precise performance data serve as a fundamental basis for the design and dimensioning of the CFRP structure by the project partners.

In the later stages of the project, Fraunhofer IWS will manufacture multilayer demonstration cells optimized for high specific energy. These cells will be integrated into the final lightweight demonstrators and electrochemically characterized to validate their performance under realistic operating conditions.

Innovation and Perspectives 

The innovation of EEdeL lies in the combination of next-generation energy storage systems with advanced lightweight engineering.

This approach opens up new possibilities, including the direct integration of battery cells into load-bearing CFRP aircraft structures – so-called structural batteries. These multifunctional materials simultaneously fulfill mechanical functions within the aircraft structure while also serving as energy storage devices. Through the final evaluation of this technology’s future potential in collaboration with the aviation industry, EEdeL paves the way for the development of tomorrow’s CO₂-neutral propulsion systems.