Roll Laminating Solar Modules Using PVB Films
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Solution Overview
Problem
Current methods for producing thin-film solar modules are complex and not automatable on an industrial scale, particularly when using polyvinyl butyral (PVB) films, and existing techniques struggle with encapsulating thin-film solar cells due to mechanical instability and the risk of blistering or delamination.
Innovation Solution
A method involving a roller composite process using a plasticizer-containing polyvinyl acetal film, where the layered body with solar cells is heated and pressed between rollers at controlled temperatures and pressures to ensure bubble-free lamination, with adjustable line pressures and surface roughness to accommodate imperfections, allowing for continuous and automated production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If casting resins or crosslinkable systems based on ethylene vinyl acetate (EVA) are used as transparent adhesives, then the adhesive can cover the solar cell units without bubbles in the uncured state, but the production process becomes complex and difficult to control, and the adhesive layer may blister or delaminate after a few years
Solution Approach 1:
The patent extracts the problematic curing step from the lamination process by using thermoplastic PVB films instead of reactive casting resins or EVA systems. The PVB films provide adhesion through thermal bonding alone, eliminating the need for hardeners or crosslinking agents, thus simplifying the production process while maintaining bubble-free encapsulation quality
Solution Approach 2:
The patent employs disposable PVB films that are applied in the uncured state and then thermally bonded. These films serve their encapsulation function without requiring complex curing cycles, and any defects can be easily replaced without affecting the entire production line, making the process more controllable and less prone to long-term blistering or delamination issues
2Reliability
If known methods for producing solar modules with solar cells embedded between PVB films are used, then encapsulation is achieved, but the process cannot be sufficiently automated to produce composite with thin-film solar modules on an industrial scale
Solution Approach 1:
The patent applies PVB films to the solar cell units in a preliminary state before final lamination, allowing the films to be positioned and adjusted easily. This preliminary application step enables subsequent automated rolling processes to complete the encapsulation efficiently, bridging the gap between quality encapsulation and industrial-scale automation
Solution Approach 2:
The patent replaces complex manual or semi-automated encapsulation mechanisms with a simplified rolling press system. The thermoplastic PVB films respond predictably to heat and pressure, allowing standard industrial rolling equipment to automate the lamination process effectively, thereby enabling scalable production while maintaining encapsulation reliability
3Adaptability or versatility
If thin-film solar modules are manufactured in any size and in large quantities, then production flexibility is improved, but the mechanical instability of thin-film solar cells makes encapsulation difficult
Solution Approach 1:
The patent changes the physical state parameters of the PVB films by controlling temperature and pressure during lamination. The films are heated to become more pliable and conform to the irregular surfaces of mechanically unstable thin-film solar cells, then cooled to provide stable encapsulation. This parameter control allows reliable bonding regardless of solar cell size or production volume
Solution Approach 2:
The patent creates a composite structure where the PVB film encapsulates the thin-film solar cells. The composite material system combines the flexibility needed to accommodate mechanically unstable solar cells with the structural integrity required for large-scale production. The PVB film acts as a protective matrix that stabilizes the solar cells while allowing size variations
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 enables the production of thin-film solar modules with improved ventilation and bonding, reducing the risk of bubbles and delamination, and allows for the use of mechanically unstable solar cells, facilitating efficient and bubble-free encapsulation suitable for industrial-scale production.
Implementation Method 1
heating the layered body in at least one heating tunnel
Implementation Method 2
pressing between at least one pair of rollers at a temperature of 50 to 150°C, in particular 60 to 150°C
Data Source
Figure 1~2
Figure 3~5
AI summary
The method involves laminating a layer body, which consists of two carriers, by a intermediate layer foil which is based on softener containing polyvinyl acetal, where a solar cell (S) is attached on one of the carriers. The layer body is guided between a pair of rollers with a temperature of 60 degree Celsius to 150 degree Celsius. The layer body is pressed between the two rollers with a line pressure of 0.5 Newton per millimeter to 100 Newton per millimeter.