Rotorcraft Energy Storage Layout With Crashable Subfloor Structure

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Solution Overview

Problem

Conventional energy storage systems in rotorcraft, such as batteries and hydrogen tanks, pose safety risks and structural integrity challenges during crashes due to their rigid nature, preventing energy dissipation and potentially endangering occupants with fire, toxic gases, or explosions.

Innovation Solution

The energy storage units are positioned outside the fuselage outer shell, particularly in the subfloor region, with a crashable structure that deforms before impact, allowing energy dissipation and separation from the cabin, and are designed for easy exchange and cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If rigid energy storage devices (batteries, hydrogen tanks) are installed inside the fuselage, then energy storage capacity is improved, but occupant safety during crash deteriorates due to prevented energy dissipation and potential fire/toxic gas release

Engineering Contradiction:
Improveenergy storage capacityVSAvoidoccupant safety during crash
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The energy storage device is extracted from the interior of the fuselage and mounted on the exterior surface. This separation removes the harmful factors (fire, toxic gases, rigid impact points) from the occupant compartment while maintaining energy storage functionality, directly resolving the safety contradiction.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

A crashable structure is introduced as an intermediary element between the energy storage device and the ground/impact surface. This mediator deforms during crash to dissipate energy, protecting both the energy storage device and the fuselage while maintaining the rigid nature of the energy storage system itself.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Use of energy by moving object

If rigid energy storage devices are used, then energy density and storage efficiency are improved, but structural integrity during crash deteriorates due to prevention of controlled deformation

Engineering Contradiction:
Improveenergy storage efficiencyVSAvoidstructural integrity during crash
Core Design Contradiction:
Use of energy by moving objectVSStrength

Solution Approach 1:

The system is segmented into two distinct functional parts: the rigid energy storage device (maintaining high energy density) and the deformable crashable structure (providing controlled deformation). This segmentation allows each component to optimize its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different parts of the system have different mechanical properties: the energy storage device maintains rigid local quality for efficient energy storage, while the crashable structure has deformable local quality for energy dissipation during impact. This local differentiation resolves the contradiction between rigidity and deformability.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If energy storage devices are mounted inside the fuselage, then ease of installation is improved, but maintenance accessibility and fire protection deteriorate

Engineering Contradiction:
Improveinstallation easeVSAvoidmaintenance accessibility
Core Design Contradiction:
Ease of manufactureVSEase of repair

Solution Approach 1:

The energy storage device is extracted to the exterior where it becomes more accessible for maintenance operations. The exterior mounting position allows technicians to reach the device directly without disassembling interior components, improving both maintenance accessibility and fire protection through external containment.

Inventive Principle:
Principle #2Taking out (Extraction)

4Loss of energy

If conventional fuel storage systems are used, then energy dissipation during crash is improved through deformable fuel bladders, but fire risk and toxic gas generation deteriorate with alternative energy sources

Engineering Contradiction:
Improvecrash energy dissipationVSAvoidfire risk and toxic gas generation
Core Design Contradiction:
Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The alternative energy storage device is extracted from the fuselage interior to the exterior, where it can be equipped with its own crashable protective structure. This separation isolates the fire and toxic gas generation risks from the occupant compartment while allowing the crashable structure to provide energy dissipation specifically for the energy storage system.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The crashable structure provides preliminary protection by deforming before the energy storage device experiences impact. This preliminary energy absorption prevents direct impact on the energy storage device, reducing the likelihood of fire or toxic gas release before such hazards can develop.

Inventive Principle:
Principle #9Preliminary anti-action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration enhances safety by containing fire and toxic gases outside the cabin, facilitates easy maintenance, and optimizes crash energy absorption, improving structural integrity and occupant protection.

Implementation Method 1

The fuselage and the fuselage outer shell form a central box-like structure in the subfloor region, and the at least one energy source storage unit is arranged laterally at the central box-like structure... The central box-like structure forms a crashable structure that contacts ground in case of a crash before the at least one energy source storage unit may contact ground in order to deform and dissipate energy.

Methodology Applied
Scientific EffectEnergy dissipation through deformation: Deformation

Data Source

PatentEP4310000B1A rotorcraft with an energy source storage unit
Publication Date: 2025.09.03 AIRBUS HELICOPTERS DEUT GMBH
  • EP4310000B1 patent drawingFigure 1
  • EP4310000B1 patent drawingFigure 2~3
  • EP4310000B1 patent drawingFigure 4~5

AI summary

A rotorcraft (1) comprising: a fuselage (2) arranged within a fuselage outer shell (2e); at least one main rotor located on top of the fuselage (2); at least one engine provided for driving the at least one main rotor; and at least one energy source storage unit (7) comprising at least one energy source (7a) configured to provide energy for powering the at least one engine for driving the at least one main rotor; wherein the at least one energy source storage unit (7) is arranged outside the fuselage outer shell (2e); and wherein the fuselage (2) and the fuselage outer shell (2e) form in vicinity of the at least one energy source storage unit (7) a crashable structure (10) configured to be crashable in an emergency landing at least for limiting effects of impact on the at least one energy source storage unit (7).