Temperature-Dependent Viscosity Encapsulant for PV Module Lamination
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Solution Overview
Problem
The manufacturing of photovoltaic modules is hindered by the complex handling of fragile solar cells and the challenges of thermal expansion stresses between different materials, leading to reliability issues and increased costs, with existing encapsulants causing alignment and shrinkage problems during lamination.
Innovation Solution
A photovoltaic module utilizing an encapsulant with a complex viscosity of at least 200,000 Pa·s at 70-100°C and less than 100,000 Pa·s at 120-160°C, providing mechanical stability and thermoplastic properties to prevent disconnection and improve handling, with the encapsulant being either a foil or granules, and containing curable components for enhanced processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional encapsulant foils are used during lamination, then the encapsulant can be easily applied, but the foils shrink during lamination causing alignment problems and requiring larger foils that protrude and need removal
Solution Approach 1:
The patent changes the viscosity parameter of the encapsulant material as a function of temperature. At processing temperature (120-160°C), the complex viscosity is low (<100,000 Pa·s) enabling easy handling and application. At service temperature (70-100°C), the complex viscosity is high (≥200,000 Pa·s) preventing shrinkage and maintaining alignment precision. This temperature-dependent viscosity parameter change resolves the contradiction between ease of operation and manufacturing precision.
2Manufacturing precision
If the encapsulant foil is made larger to compensate for shrinkage, then alignment during lamination is improved, but the protruding foil must be removed after lamination prolonging processing time
Solution Approach 1:
The patent uses temperature-dependent viscosity changes to eliminate the need for oversized foils. The low viscosity at processing temperature allows precise application without excessive shrinkage, while the high viscosity at service temperature prevents any shrinkage that would require compensation. This eliminates the need for post-lamination foil removal, improving productivity while maintaining alignment precision.
3Ease of operation
If thermoplastic encapsulant foils are used, then the foils can be easily applied, but they stick to machine parts during lamination requiring regular cleaning
Solution Approach 1:
The patent changes the viscosity parameter with temperature to resolve the adhesion problem. At processing temperature (120-160°C), the low complex viscosity (<100,000 Pa·s) allows easy application without excessive adhesion to machine parts. At service temperature (70-100°C), the high complex viscosity (≥200,000 Pa·s) prevents the encapsulant from sticking to conveyor belts and pressing membranes, eliminating the need for regular cleaning while maintaining ease of operation during application.
4Ease of manufacture
If solar cells are handled during manufacturing, then the modules can be assembled, but the fragile solar cells are difficult to handle leading to reduced throughput and yield
Solution Approach 1:
The patent applies preliminary action by providing mechanical support and protection to solar cells through the high-viscosity encapsulant before and during assembly operations. The encapsulant's high complex viscosity at service temperature (≥200,000 Pa·s at 70-100°C) provides immediate structural support, reducing handling difficulties and enabling faster assembly operations, thereby improving both ease of manufacture and productivity.
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 high viscosity encapsulant ensures stability against thermal stresses, improves manufacturing throughput, reduces defects, and maintains electrical contact, while the thermoplastic properties facilitate easier handling and reduce material waste, resulting in a more reliable and cost-effective photovoltaic module.
Implementation Method 1
an encapsulant (3) covering the photoactive components (2) from both sides. The encapsulant (3) is formed from a material having at a first temperature a first complex viscosity and at a second temperature a second complex viscosity, wherein the first complex viscosity is larger than the second complex viscosity
Data Source
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AI summary
The invention relates to a photovoltaic module (1) comprising - at least one photoactive component (2), such as a solar cell or a thin film, and - an encapsulant (3) covering the at least one photoactive component (2) on at least one side, wherein the encapsulant (3) is formed from a material having at a first temperature a first complex viscosity and at a second temperature a second complex viscosity, wherein the first complex viscosity is larger than the second complex viscosity and wherein the first temperature is between 70°C and 100°C and the second temperature is between 120°C and 160°C, characterized in that the first complex viscosity amounts to at least 100.000 Pa·s, preferably to at least 200.000 Pa·s.