MATISSE responds to the fourth bullet of the HORIZON-CL5-2021-D5-01-05 topic “expected outcome”, delivering improved aircraft technologies in the area of multifunctional structures capable of storing electrical energy for hybrid electric aircraft applications. This consists in integrating Li-ion cells into aeronautical composite structures, sharing the load-bearing function with the structure and achieving an aircraft structural element capable of functioning as a battery module. To do so, MATISSE will:
• advance Li-ion battery cell technology, in a non-conventional formulation suitable for bearing structural loads: NMC811 (cathode), Si/C (anode) and bicontinuous polymer-ionic quasi-solid-state electrolyte (BCE), i.e. NMC811|BCE|Si/C, achieving 170-270 Wh/kg at cell level;
• enable the functional integration of Li-ion cells into solid laminate and sandwich composite structures;
• make the structural battery smart, by equipping it with on-cell and in-structure sensors, connected to a chip-based CMU (Cell Monitoring Unit) and PLC (Power Line Communication).

MATISSE delivers a multifunctional structure demonstrator capable of power delivery, power management and safety monitoring. This consists of a full-scale wing tip (1.42 m × 0.69 m) for use in place of the current wingtip assembly installed on Pipistrel Velis Electro, embedding a module of 40 battery cells at 72 VDC. This will undergo a comprehensive testing and characterisation campaign, qualifying the technology at TRL 4 at the end of the project (2025). MATISSE will also encompass aspects related to flight certification, life-cycle sustainability and virtual scale-up, paving the way towards the application of structural batteries as an improved performance key enabling technology for next generation commuter and regional hybrid electric aircraft applications.