LIME project to develop hybrid-electric aircraft battery system with composite casing

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On Sept. 10, the European project Lithium-based Innovation for Modular Energy (LIME) officially launched under the umbrella of Europe’s Clean Aviation program, with a €5 million grant awarded to the consortium led by Exoes, Ascendance Flight Technologies, Basquevolt and RWTH Aachen University. This recognition reflects strong support from major aircraft manufacturers including Airbus, ATR and Daher.

The LIME project aims to develop a next-generation battery system for an ultra-efficient hybrid-electric aircraft concept. The system will be designed to meet CS-23 and CS-25 certification standards, with a focus on safety, modularity and integration into future hybrid-electric propulsion architectures. This initiative is part of Clean Aviation’s broader mission to accelerate the decarbonization of air transport and contribute to the EU’s climate goals.

The project addresses six key objectives for the aerospace industry: 

• Safety and end-user-centric design: Design a battery system that meets stringent certification standards and user requirements for aviation, especially CS25 applications. 
• Disruptive battery innovation: Push the boundaries of current technology with a battery system surpassing existing capabilities in cell technology, thermal management and composite casing.
• TRL 4 prototyping: Manufacture and test a TRL 4 prototype including cell blocks, battery management and thermal systems, followed by ground demonstrations.
• Digital twin agility: Use high-fidelity digital twins to optimize development, reduce costs and minimize physical prototyping, ensuring rapid design validation. 
• Roadmap to entry into service: Support integration studies and create an industrialization plan to prepare the battery system for service in regional aircraft, specifically targeting the ATR 42/72 for entry into service by 2035. 
• Maximize European impact: Advance critical aviation technology to benefit European society, economy and competitiveness by disseminating research and results widely.

Exoes (Gradignan), a French company specializing in high-voltage battery systems, thermal management and hazardous testing, is responsible for the design, prototyping and testing of the cell blocks. The company brings its expertise in high-performance battery and cooling technologies and system integration to ensure performance, safety and certification readiness.