Strain Isolation Layer for Solar Panels on Aircraft

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Solution Overview

Problem

Existing methods for mounting photovoltaic solar cells and solar panels on structures, such as aircraft and vehicles, face challenges due to strain limitations, thermal expansion issues, and buckling or wrinkling, leading to reduced efficiency and increased costs and complexity.

Innovation Solution

A strain isolation layer assembly with a discontinuous configuration, vertical rigidity, and horizontal shear flexibility is introduced, coupled between a rigid solar layer and an underlying substrate layer to isolate and reduce strains, using materials like perforated foam or column support layers to stabilize the solar panels and prevent buckling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If photovoltaic solar cells are directly connected to the vehicle structure, then the solar cells can be mounted securely, but the solar cells are forced to approximate the same strain levels as the vehicle structure which exceeds their strain limit

Engineering Contradiction:
Improvemounting securityVSAvoidsolar cell functionality
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

A strain isolation layer is introduced as an intermediary component between the solar cell array and the vehicle structure. This layer has discontinuous configuration with vertical rigidity to support the solar cells while horizontal shear flexibility to isolate strains, preventing strain transmission from the vehicle structure to the solar cells while maintaining secure mounting.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Shape

If thin solar cells are curved to follow the wing surface curvature, then they can be mounted on the aircraft surface, but they buckle under compressive strains even at very low strain levels

Engineering Contradiction:
Improvecurvature conformityVSAvoidstructural stability
Core Design Contradiction:
ShapeVSStability of the object's composition

Solution Approach 1:

The strain isolation layer functions as a flexible intermediate structure that can accommodate the curvature of the wing surface while providing sufficient support to prevent buckling of the thin solar cells. The layer's discontinuous configuration with vertical rigidity provides the necessary support without constraining the solar cells excessively.

Inventive Principle:
Principle #30Flexible shells and thin films

3Ease of manufacture

If solar cells are bonded to materials with different coefficients of thermal expansion, then they can be mounted on the structure, but thermal strains are induced on the solar cells when temperature changes

Engineering Contradiction:
Improvemounting feasibilityVSAvoidsolar cell performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The strain isolation layer serves as a thermal buffer between the solar cells and the vehicle structure. Its discontinuous configuration and shear flexibility allow it to accommodate differential thermal expansion between materials with different CTEs, reducing thermal strain transmission to the solar cells while maintaining mounting feasibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If gaps are provided between solar cells to accommodate strains, then strain tolerance is improved, but gaps disrupt laminar flow and increase complexity

Engineering Contradiction:
Improvestrain toleranceVSAvoidmounting complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The strain accommodation function is extracted from the solar cell mounting structure itself and transferred to the separate strain isolation layer. This allows the solar cells to be mounted continuously without gaps for strain accommodation, while the strain isolation layer handles strain absorption through its discontinuous configuration and shear flexibility.

Inventive Principle:
Principle #2Taking out (Extraction)

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 solution effectively reduces mechanical and thermal strains on solar panels, preventing buckling and wrinkling, while simplifying the mounting process, reducing costs, and maintaining the structural integrity and efficiency of the solar panels.

Implementation Method 1

a strain isolation layer having a discontinuous configuration, a vertical rigidity, and a horizontal shear flexibility

Methodology Applied
Scientific EffectShear flexibility: Shear Stress

Implementation Method 2

thermal strains may be induced on photovoltaic solar cells or solar arrays if they are bonded or attached to materials with different coefficients of thermal expansion (CTEs) when the temperature changes

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP2774185B1Strain isolation layer assemblies and methods
Publication Date: 2019.02.20 THE BOEING CO
  • EP2774185B1 patent drawingFigure 1
  • EP2774185B1 patent drawingFigure 2
  • EP2774185B1 patent drawingFigure 3A~3B

AI summary

In an embodiment of the disclosure, there is provided a strain isolation layer assembly. The assembly has a rigid solar layer; a strain isolation layer having a discontinuous configuration, a vertical rigidity, and a horizontal shear flexibility; and an underlying substrate layer. The strain isolation layer is coupled between the rigid solar layer and the underlying substrate layer to form a strain isolation layer assembly, such that the strain isolation layer isolates the rigid solar layer to reduce one or more strains induced on the rigid solar layer.