Solar Cell Unit Optical Element Adhesion

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Solution Overview

Problem

Existing solar cell units face challenges in protecting semiconductor bodies from environmental degradation and maintaining optical efficiency under high sunlight concentration, particularly due to limitations in adhesive materials that are transparent, UV-resistant, and temperature-stable, which affects the reliability and efficiency of solar cell performance.

Innovation Solution

A solar cell unit design featuring a semiconductor body with a secondary optical element having a flat underside with an adhesion promoter layer and a polymer adhesive layer, which forms a non-positive connection with the semiconductor body, ensuring reliable adhesion and protection against environmental influences while maintaining optical efficiency, and optionally includes a metal layer for enhanced heat transfer and radiation distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a polymer adhesive layer is used to bond the optical element to the semiconductor body, then ease of manufacture is improved, but reliability deteriorates due to delamination under high temperature and UV exposure

Engineering Contradiction:
Improveease of manufactureVSAvoidreliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies composite materials by combining the polymer adhesive layer with an adhesion promoter layer. This composite structure leverages the ease of application and optical transparency of the polymer adhesive while the adhesion promoter layer provides enhanced bonding strength and resistance to delamination under high temperature and UV exposure conditions.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The adhesion promoter layer serves as an intermediary between the optical element and the polymer adhesive layer. This intermediate layer improves the bonding interface, preventing direct contact between the polymer adhesive and the optical element surfaces that would otherwise lead to delamination under thermal and UV stress.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of energy

If the adhesive layer is made transparent to maintain optical efficiency, then optical losses are reduced, but protection against environmental degradation worsens due to UV resistance requirements

Engineering Contradiction:
Improveoptical lossesVSAvoidUV resistance
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent uses composite materials by combining the transparent polymer adhesive layer with the adhesion promoter layer. This composite structure maintains optical transparency for efficient light transmission while the adhesion promoter provides UV resistance and protection against environmental degradation.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by having different layers perform different functions: the polymer adhesive layer provides optical transparency and bonding, while the adhesion promoter layer specifically addresses UV resistance and environmental protection at the bonding interface.

Inventive Principle:
Principle #3Local quality

3Power

If high concentration of sunlight is used to increase power output, then power is improved, but temperature increases causing adhesive degradation

Engineering Contradiction:
ImprovepowerVSAvoidtemperature
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The patent applies composite materials by combining the polymer adhesive layer with the adhesion promoter layer, creating a thermally stable bonding structure that can withstand the high temperatures generated by concentrated sunlight while maintaining adhesive properties.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The adhesion promoter layer provides beforehand cushioning by pre-establishing a thermally stable bonding interface that protects against thermal degradation before it occurs. This preventive measure cushions the adhesive joint against the thermal stress of concentrated sunlight.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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

The design enhances the reliability and longevity of solar cell units by reducing delamination risks and maintaining high efficiency under high temperature and UV exposure, with a simplified manufacturing process and reduced optical losses, making it suitable for concentrated photovoltaic systems.

Implementation Method 1

part of the underside of the optical element has a first adhesion promoter layer which is materially bonded to the underside

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

a polymer adhesive layer is at least between the adhesion promoter layer and the front side of the semiconductor body is formed

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 3

a secondary optical element, which has an underside and guides light onto the front side of the semiconductor body

Methodology Applied
Scientific EffectLight guidance: Optical Fibre

Implementation Method 4

the polymer adhesive layer must be particularly transparent in the entire spectral range to be used

Methodology Applied
Scientific EffectOptical transparency:

Implementation Method 5

in addition to high UV resistance

Methodology Applied
Scientific EffectUV resistance:

Implementation Method 6

the polymer adhesive layer must be particularly temperature and aging resistant

Methodology Applied
Scientific EffectThermal resistance:

Data Source

PatentEP2693495B1Solar cell unit
Publication Date: 2020.09.09 AZUR SPACE SOLAR POWER
  • EP2693495B1 patent drawingFigure 1~3
  • EP2693495B1 patent drawingFigure 4a~5c

AI summary

The unit (10) has a semiconductor body (20) designed as a solar cell and comprising front and rear sides. A carrier (30) has conducting path areas (40, 45) formed on upper and lower sides, respectively. A secondary optical element (22) guides light to the front side of the body and has a planar surface on a lower side (24), where a part of the lower side of element has an adhesive layer (25) that is connected with the lower side in a firmly-bonded manner. A polymer adhesive layer i.e. silicone layer (60), is arranged between the adhesive layer and the front side of the body. The solar cell is designed as a multipart solar cell.