A joint study by TU Delft and Elysian Aircraft reveals a new role for batteries in aircraft structures—not only as an energy source but also as the key to lightweight design.

In conventional thinking, the high weight of batteries has been the biggest obstacle to electric aviation. But latest research shows that when batteries are properly “embedded” into the wing structure, they become a core tool for structural weight reduction.

We have recently analyzed a research report (AIAA 2025–3470) jointly published by Delft University of Technology (TU Delft) and Elysian Aircraft. Focusing on the 90-seat electric aircraft Elysian E9X, the study systematically evaluates the impact of wing-integrated batteries on structural design. Below are the three major technological breakthroughs and commercial insights we have summarized.

1. Batteries Are No Longer a Burden, but a “Bending Mitigator”

Weight Reduction Effect:

Compared with mounting batteries in the fuselage, the wing-integrated solution reduces wing structural weight by approximately 32%.

Bending Relief Mechanism:

The physical mass of batteries is distributed spanwise along the wing, effectively counteracting the upward bending moment of the wing during flight. This greatly reduces bending stress at the wing root and directly lowers the demand for structural reinforcement materials.

• Composite Materials + Wide Wingbox = Lighter, Stronger, Higher Energy Capacity

Great Potential of Composite Materials:

The study shows that using carbon fiber-reinforced polymer (CFRP) can further reduce wing mass by about 22% compared with conventional aluminum alloys.

Airfoil Thickness Optimization:

Appropriately increasing the thickness-to-chord ratio (t/c) at the wing root may slightly compromise aerodynamic performance, but the improved structural strength delivers a full-wing weight reduction of up to 8%.

• Space Utilization: The Wide-wingbox Strategy

Planning internal wing space is critical to accommodating more energy storage.

Win-Win of Capacity and Weight:

A wider wingbox structure (e.g., front and rear spars located at 5% and 65% of the chord length) provides approximately 39% more usable volume than a narrow wingbox.

This design not only integrates more battery cells but can even be lighter than narrow wingbox designs under given structural constraints.

4. Key Conclusion: The New Role of Battery Suppliers

The realization of large electric aircraft (such as 90-seat models) no longer depends only on breakthroughs in battery energy density, but more on highly integrated design of batteries and wing structures.

Battery distribution has become an important design variable in aircraft aeroelastic optimization.

The mass distribution and installation location of batteries (e.g., coordination with landing gear span) significantly affect the overall structural mass and flight safety.

This means: future aviation battery suppliers must understand not only electrochemistry but also aeroelasticity.

• Closing Remarks:

Electric aircraft design is shifting from “energy density–driven” to “structure–energy integration”.

Batteries are no longer a black box. They Are Part of the Wing!

What we offer is exactly this integrable structural solution.

Want to gain a deep understanding of the structural design of blended wing-body batteries?

The key charts and core conclusions of the original research paper (AIAA 2025-3470) are available. A complete report is provided for your reference. Free access is welcome.