RFPs: Design and Integration of a High-Performance Battery System on a Hybrid-Electric Regional Aircraft

Design and demonstration of a high gravimetric energy density battery system (comprising cells, battery management system, housing), the thermal management concept, and interfaces to relevant aircraft systems for hybrid-electric regional application. The topic covers ground demonstrations to TRL4, paving the way for further research to reach TRL5 and TRL6 demonstrations.

Scope

• The project scope is therefore to design and demonstrate to TRL4 a battery system for hybrid-electric propulsion, including:
  • Evaluation of safety requirements for battery system hardware and software (EASA SC-VTOL MOC-3, aircraft manufacturer end-user inputs, state of the art in lower power applications)
  • Development of packs based on different cells (including all sensors deemed necessary to deliver the required data to the aircraft systems, regarding temperature, state of charge, state of health…)
  • Development of a Battery Management System providing all interfaces deemed necessary and being able to compute the different data exchange protocols and to support energy management strategies on board the aircraft
  • Development of a thermal management concept for the battery system (temperature control and heat dissipation, incl. thermal runaway protection concepts) and integration with the overarching thermal management concept on aircraft level.
  • Evaluation of the optimal position of the battery in the airframe with regard to thermal management, Electrical Power Generation and Distribution System integration, maintenance, and considering the aircraft integration constraints to be provided by the regional aircraft concept “end user” (space allocation, centre of gravity, safety, environment…).
  • Design of the housing for the complete system (weight optimization, material selection and mechanical design, airworthiness and crashworthiness).
  • Building on the BATT4EU partnership battery roadmap for aviation, expand and instantiate a battery roadmap to improve the packs to meet the specific aircraft level requirements of UltraEfficient Regional Aircraft concept (e.g. improvement of weight, gravimetric and volumetric energy density…), considering new cell developments outside of the Clean Aviation programme (e.g. from BATT4EU partnership, or other national projects).
  • Modular multiplication of initial packs/modules to build up an high-power system suitable for the aircraft-level requirements.
  • The modelling of the requirements and the creation of an experimentally validated digital twin allowing to simulate external influences (e.g. from electrical and thermal integration, controland safety systems) as well as design changes (e.g. other cells, scalability) and to simulate key data for subsequent aircraft integration and certification.

Performance Targets

• The performance of the battery system shall be compatible with an electrical a propulsive power of up to 1MW per side, on CS-25 aircraft:
  • Gravimetric energy density of minimum 250Wh/kg at pack level, and exploration of cell technology for higher energy density up to 500Wh/kg at pack level, in particular based on solid-state cells technology. The weight reduction from optimal placement of the battery on the airframe must be considered as well.
  • Voltage compatibility with aircraft level EPGDS system, considering HV grids within range of 550V – 950V to cover full battery operational range in discharge and charge modes, with a Nominal value of 800Vfor propulsive energy distribution.
  • Efficiency > 90% (ratio of energy output to input during discharge and charge cycles), to be specified based on end-user requirements and considered technology.
  • Service-life in cycles compatible with aircraft maintenance checks, typically up to thousands of cycles, to be specified based on end-user requirements.
  • Capacity, Power, Discharge C-rate compatible with hybridization profile and ratio in critical high-power phases (Take-Off, Top-of-climb), to be established in cooperation with the aircraft concept end-user.
  • Charge C-rate compatible with airport operation with typical turnaround times of about 30min (C-rate about 2).
  • Targets must be compatible with safety as an overarching requirement, considering airworthiness requirements and in particular thermal runaway protection.
• The performance targets, including KPIs, should be defined and calibrated:
  • with the objective of meeting or exceeding the project goals at completion, allowing efficient progress monitoring and providing a sound basis for subsequent work in view of best contributing to the achievement of overall high-level goals.
  • consistently with all constraints pertaining to the design and integration on a regional aircraft with hybrid-electric propulsion, as defined by the end-user.

Funding Information

• Indicative budget
  • The total indicative funding budget for the topic is EUR 5 million.
  • The Clean Aviation Joint Undertaking may award up to 1 project with funding depending on the outcome of the evaluation and the complementarity of the proposed actions.
• Indicative project duration
  • Maximum 24 months.

Expected Outcomes 

• Project results are expected to demonstrate a battery system for hybrid-electric propulsion, primarily for an Ultra-Efficient Regional aircraft concept considered for Entry into Service by 2035.
• This a battery system is a key technology for the ultra-efficient aircraft concepts proposed in Clean Aviation SRIA, aiming at 30% emissions reduction at aircraft level, compared to 2020 SoA aircraft (enabling 86% net CO2 reduction with 100% SAF).
• Adequate KPIs at integrated system & key techno levels shall be proposed to support the effective achievement of the expected outcomes
• This project should consider cooperation and alignment with the Clean Aviation Ultra-Efficient Regional aircraft concept, which is a battery-based hybrid-electric concept, as a use-case for this fasttrack activity.
• The project shall identify potential synergies with the related activities funded under research and innovation programmes at regional, national and European level, and demonstrate how the project will benefit from these activities.

Eligibility Criteria

• Special eligibility condition – limitation of the types of legal entities eligible to coordinate the project
  • The coordinator role shall be limited to legal entities having the following type of organisation:
    •  University
    • Research and Technology Organisation (RTO) or
    • SME (legal entities are advised to confirm their SME status)
• Any legal entity, regardless of its place of establishment, including legal entities from no associated third countries or international organisations (including international European research organisations) is eligible to participate (whether it is eligible for funding or not), provided that the conditions laid down in the Horizon Europe Regulation have been met, along with any other conditions laid down in the specific call/topic.
• A ‘legal entity’ means any natural or legal person created and recognised as such under national law, EU law or international law, which has legal personality and which may, acting in its own name, exercise rights and be subject to obligations, or an entity without legal personality.
• Entities eligible for funding:
  • To be eligible for funding, applicants must be established in one of the following countries:
    • the Member States of the European Union, including their outermost regions:
      • Austria, Belgium, Bulgaria, Croatia, Cyprus, Czechia, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden.
    • the Overseas Countries and Territories (OCTs) linked to the Member States:
      • Aruba (NL), Bonaire (NL), Curação (NL), French Polynesia (FR), French Southern and Antarctic Territories (FR), Greenland (DK), New Caledonia (FR), Saba (NL), Saint Barthélemy (FR), Sint Eustatius (NL), Sint Maarten (NL), St. Pierre and Miquelon (FR), Wallis and Futuna Islands (FR).
    • Countries associated to Horizon Europe;
      • Albania, Armenia, Bosnia and Herzegovina, Faroe Islands, Georgia, Iceland, Israel, Kosovo, Moldova, Montenegro, New Zealand, North Macedonia, Norway, Serbia, Tunisia, Türkiye, Ukraine, United Kingdom.

For more information, visit EC.