Photovoltaic Module Encapsulation with Refractive Index Matching

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Solution Overview

Problem

Conventional photovoltaic modules face challenges in maintaining optical transmittance and mechanical strength while minimizing weight and manufacturing costs, often compromising efficiency due to the use of fiber-reinforced thermosetting resin composites that lead to light diffusion.

Innovation Solution

The use of a fiber-reinforced thermosetting composite material with a substantially transparent resin and fibers having matching refractive indices, combined with silane-treated glass fibers and a low void content, reduces light diffusion and enhances mechanical properties, allowing for self-supporting modules with improved efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If fiber-reinforced thermosetting resin composite material is used for encapsulation, then mechanical strength and structural capacity are improved, but optical transmittance deteriorates due to light diffusion

Engineering Contradiction:
Improvemechanical strengthVSAvoidoptical transmittance
Core Design Contradiction:
StrengthVSIllumination intensity

Solution Approach 1:

The refractive index of the resin is specifically adjusted to match that of the fibers (both substantially equal to 1.5), which minimizes light diffusion at the fiber-resin interface. This parameter matching allows the composite material to maintain both mechanical strength and high optical transmittance, resolving the contradiction between structural capacity and light transmission efficiency

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

A composite material system is designed comprising transparent fibers embedded in a transparent resin matrix, where both components are specifically selected for their optical compatibility. The composite structure provides mechanical reinforcement while the matched refractive indices ensure minimal light scattering, achieving both structural and optical performance requirements

Inventive Principle:
Principle #40Composite materials

2Reliability

If conventional laminate structure with back sheet, front sheet and encapsulant is used, then protection and structural support are improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
ImproveprotectionVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple functional components (back sheet, front sheet, and encapsulant) are merged into a single integrated fiber-reinforced composite encapsulation layer. This multi-functional integration provides structural support, mechanical protection, and electrical insulation simultaneously, reducing manufacturing complexity and eliminating the need for separate assembly steps while maintaining comprehensive protection

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The fiber-reinforced composite encapsulation is designed to perform multiple functions: structural reinforcement, mechanical protection of cells, electrical insulation, and optical transparency for light transmission. This multi-functionality replaces several separate components with a single universal encapsulation system, simplifying the overall module structure

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Weight of moving object

If fiber-reinforced composite material is used, then weight is reduced compared to conventional structures, but manufacturing precision deteriorates due to difficulty in achieving uniform fiber distribution

Engineering Contradiction:
Improvemodule weightVSAvoidfiber distribution uniformity
Core Design Contradiction:
Weight of moving objectVSManufacturing precision

Solution Approach 1:

The resin viscosity is specifically controlled and adjusted to optimal ranges that enable thorough impregnation of fibers during the curing process. This parameter optimization ensures uniform fiber distribution and complete void elimination while maintaining the lightweight characteristics of the composite material, achieving both weight reduction and manufacturing precision

Inventive Principle:
Principle #35Parameter changes

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 photovoltaic modules with increased efficiency, structural capacity, and reduced manufacturing stages, eliminating the need for additional materials and minimizing light diffusion, while maintaining high optical transmittance and mechanical strength.

Implementation Method 1

the refractive indices of the resin and the fibers are substantially the same

Methodology Applied
Scientific EffectRefractive index matching: Refraction

Implementation Method 2

combined with silane-treated glass fibers

Methodology Applied
Scientific EffectSilane treatment: Chemical Bonding

Implementation Method 3

photovoltaic cells having a front side to be irradiated and a back side

Methodology Applied
Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Data Source

PatentEP3191284B1Method for manufacturing encapsulated photovoltaic modules
Publication Date: 2022.03.30 FUNDACION TECNALIA RESEARCH & INNOVATION
  • EP3191284B1 patent drawingFigure 1~2a
  • EP3191284B1 patent drawingFigure 2b
  • EP3191284B1 patent drawingFigure 3a~4

AI summary

The disclosure relates to photovoltaic modules comprising one or more photovoltaic cells embedded in a fiber-reinforced composite thermosetting material, wherein at a front side of the photovoltaic cells, the fiber-reinforced composite material comprises a substantially transparent resin, and substantially transparent fibers, and wherein the refractive indices of the resin and the glass fibers are substantially the same. In particular, the fibers can be glass fibers treated with aminosilane coupling agents and the resin can be an epoxy resin. Further disclosed are methods of manufacture of photovoltaic modules comprising one or more crystalline silicon photovoltaic cells comprising: providing a mold, one or more photovoltaic cells in the mold, and reinforcement fibers in the mold and positioning a bag surrounding the mold cavity. Then a vacuum is created in the bag substantially gradually, and the resin is infused with the mold due to the created vacuum.