Solar Cell Assembly on Airfoils With Co-Cured Smooth Composite Skin

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Solution Overview

Problem

There is a need for improved methods of manufacturing and assembling photovoltaic solar arrays that can reduce costs and increase performance, particularly for aerospace applications where a highly smooth surface is required to achieve laminar flow, and existing methods are inefficient in achieving these goals.

Innovation Solution

The method involves using an assembly fixture with a smooth, concave surface to mount ethylene tetrafluoroethylene (ETFE) film, followed by a non-crosslinked silicone pressure-sensitive adhesive (PSA) film, and then an array of interconnected III-V compound semiconductor multijunction solar cells, which are bonded to a composite material support using a co-curing process, allowing for easy removal and a smooth outer surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional solar cells are mounted on a support using traditional assembly methods, then the solar cells can be interconnected to form arrays, but the surface smoothness required for laminar flow in aerospace applications cannot be achieved

Engineering Contradiction:
Improvesurface smoothnessVSAvoidassembly complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The adhesive film is applied to the support structure before the solar cells are positioned, creating a pre-prepared bonding surface that ensures smooth adhesion and eliminates post-assembly surface irregularities, thereby achieving the required surface smoothness for aerospace applications

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A specialized adhesive film serves as an intermediary layer between the support structure and the solar cells, providing a smooth bonding interface that maintains surface smoothness while facilitating the connection of solar cells to the aerodynamic surface

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If III-V compound semiconductor multijunction solar cells are used to achieve high energy conversion efficiency, then performance is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveenergy conversion efficiencyVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The solar cells are segmented into individual units that are separately positioned and bonded to the support structure using the adhesive film, allowing for simplified handling and assembly of complex III-V multijunction cells while maintaining their high efficiency characteristics

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Traditional mechanical bonding methods are replaced with adhesive bonding using a specialized film, which simplifies the assembly process for complex III-V multijunction solar cells while maintaining structural integrity and electrical performance

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If solar cell arrays are assembled using traditional methods, then interconnection is achieved, but assembly time and production cost increase

Engineering Contradiction:
Improveassembly speedVSAvoidassembly time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

Multiple assembly operations are merged into a single bonding process where the adhesive film simultaneously provides positioning, alignment, and bonding functions, eliminating sequential steps and significantly reducing assembly time for solar cell arrays

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The adhesive film provides self-aligning and self-positioning properties that allow solar cells to be automatically positioned correctly during assembly, reducing the need for precise manual alignment and accelerating the assembly process

Inventive Principle:
Principle #25Self-service

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 approach results in a cost-effective and high-performance solar cell panel assembly with a smooth outer surface, enhancing aerodynamic performance and reducing assembly complexity, while maintaining high energy conversion efficiency.

Implementation Method 1

mounting a film composed of a non-crosslinked silicone pressure sensitive adhesive (PSA) directly over the ETFE film; mounting an array of interconnected solar cells directly over the adhesive film

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Implementation Method 2

bonding the bottom surface of the adhesive film to the top surface of the face sheet by co-curing; mounting an array of interconnected solar cells, each having a top (or light-facing) side, and a back side, directly over the adhesive film; mounting an uncured supporting film composed of a composite material directly on the back side of the solar cell array adjacent the adhesive film; co-curing the film of composite material so that the array of interconnected solar cells is bonded to the supporting film

Methodology Applied
Scientific EffectCo-curing: Chemical Bonding

Data Source

PatentEP4050663B1Assembly and mounting of solar cells
Publication Date: 2023.12.06 SOLAERO TECHNOLOGIES CORP
  • EP4050663B1 patent drawingFigure 1~2
  • EP4050663B1 patent drawingFigure 3~4
  • EP4050663B1 patent drawingFigure 5~6

AI summary

A method of fabricating a solar cell assembly is disclosed, which may be applied particularly to an airfoil. The disclosure further relates to the airfoil or airfoil skin so fabricated, including a solar cell array arranged on the surface of the airfoil by providing and utilizing an assembly fixture having a smooth, concave surface. An uncured supporting film composed of a composite material (such as a carbon fiber composite) is mounted directly on the back side of the solar cells; and the film of composite material is co-cured on the assembly fixture so that the array of interconnected solar cells is bonded to the supporting film. The bonded and cured film of composite material and an array of interconnected solar cells is then removed from the assembly fixture.