Tandem Photovoltaic Interlayer Structure for Void-Free Dielectric Isolation

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Solution Overview

Problem

Existing tandem photovoltaic devices face challenges in achieving high efficiency and manufacturability due to the difficulty in providing an interlayer with desired electrical, optical, physical, and thermal properties.

Innovation Solution

A tandem photovoltaic device is designed with an interlayer comprising a first conformal layer, a second conformal layer, and a core layer. The conformal layers are made of polymers with melting points less than 170 degrees C, while the core layer is made of a polymer with a melting point greater than 200 degrees C, ensuring dielectric resistance and minimizing voids between submodules.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single-layer interlayer is used between submodules, then the device structure is simple, but it is difficult to achieve desired electrical, optical, physical, and thermal properties simultaneously

Engineering Contradiction:
Improveinterlayer structureVSAvoidinterlayer performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The interlayer is divided into multiple functional layers: a first conformal layer for optimizing optical interface and minimizing voids, a second conformal layer for additional conformality, and a core layer for providing dielectric resistance. This segmentation allows each layer to specialize in specific functions, achieving comprehensive performance requirements that a single layer cannot satisfy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The interlayer uses composite material structure with different polymer materials having distinct melting points and properties. The conformal layers use polymers with melting points less than 170°C for good conformality, while the core layer uses polymers with melting points greater than 200°C for dielectric resistance. This composite approach combines advantages of different materials to achieve multiple performance targets simultaneously.

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If conformal layers with low melting point polymers are used, then the optical interface is optimized and voids are minimized, but dielectric resistance may be compromised

Engineering Contradiction:
Improveoptical interface qualityVSAvoiddielectric resistance
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The interlayer is segmented into conformal layers for optical optimization and a core layer for dielectric resistance. The conformal layers (first and second) use low melting point polymers to minimize voids and optimize optical interface, while the core layer uses high melting point polymers to provide dielectric resistance, ensuring both functions are fulfilled by appropriate layer specialization.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the interlayer have different material properties tailored to local functional requirements. The conformal layers have low melting point polymers for optimal conformality and optical contact, while the core layer has high melting point polymers for dielectric resistance. This local quality differentiation allows each region to perform its specific function effectively.

Inventive Principle:
Principle #3Local quality

3Reliability

If high melting point polymers are used throughout the interlayer, then dielectric resistance is maintained, but conformality to submodule surfaces is reduced

Engineering Contradiction:
Improvedielectric resistanceVSAvoidconformality to surface
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The interlayer is divided into conformal layers and a core layer with distinct material properties. The first and second conformal layers use low melting point polymers that can flow and conform to the submodule surfaces during assembly, while the core layer uses high melting point polymers for dielectric resistance. This segmentation allows conformality and dielectric resistance to be achieved in different layers respectively.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The melting point parameter of the polymer materials is varied across different layers of the interlayer. The conformal layers have melting points less than 170°C to enable good surface conformality during assembly, while the core layer has melting points greater than 200°C to ensure dielectric resistance. This parameter change across layers optimizes both conformality and electrical performance.

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

The interlayer structure enhances the optical interface between submodules, maintains dielectric resistance, and prevents shorting, thereby optimizing the performance and manufacturability of tandem photovoltaic devices.

Implementation Method 1

The first conformal layer can include a first polymer having a melting point less than about 170 degrees C. The second conformal layer can include a second polymer having a melting point less than about 170 degrees C.

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

The core layer can include a third polymer having a melting point greater than about 200 degrees C. The interlayer can maintain a desired dielectric resistance between the first and second submodules.

Methodology Applied
Scientific EffectThermal stability:

Implementation Method 3

A photovoltaic device generates electrical power by converting light into electricity using semiconductor materials that exhibit the photovoltaic effect.

Methodology Applied
Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Data Source

PatentEP4416763B1Materials and methods for tandem photovoltaic devices
Publication Date: 2025.04.09 FIRST SOLAR INC
  • EP4416763B1 patent drawingFigure 1
  • EP4416763B1 patent drawingFigure 2
  • EP4416763B1 patent drawingFigure 3

AI summary

Structures and methods for making and using tandem photovoltaic devices are provided, where such devices can include a first submodule, a second submodule, and an interlayer disposed between the first submodule and the second submodule. The interlayer permits a portion of light to pass therethrough and includes first and second conformal layers along with a core layer. The first conformal layer directly contacts and conforms to a surface of the first submodule, the second conformal layer directly contacts and conforms to a surface of the second submodule, and the core layer is disposed between the first conformal layer and the second conformal layer.