Vacuum Lamination Sequence for Bubble-Free Photovoltaic Modules
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Solution Overview
Problem
Existing methods for laminating photovoltaic modules using vacuum lamination presses often result in the formation of bubbles due to trapped gases, which can reduce the lifespan of the modules and require lengthy processing times, as they typically evacuate the chamber before heating, leading to inefficient use of the lamination press and potential damage to fragile silicon solar cells.
Innovation Solution
The method involves applying a low preliminary load to the work piece, preheating it below the adhesive layer's activation temperature, and then increasing the load after the adhesive layer is softened, allowing for controlled evacuation of gases and heat transfer, which prevents bubble formation and accelerates the lamination process by using higher processing loads and temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vacuum chamber is evacuated before heating the work piece, then trapped gases can be removed, but the processing time is extended and the lamination press efficiency is reduced
Solution Approach 1:
The work piece is preheated to a temperature below the adhesive layer's activation temperature before evacuation. This preliminary heating action softens the adhesive layer in advance, allowing gases to be removed more efficiently during the subsequent evacuation phase, thereby reducing the overall processing time while still preventing bubble formation.
Solution Approach 2:
The patent changes the temperature parameter of the work piece before evacuation, heating it to a state where the adhesive layer begins to soften but has not yet reached full activation temperature. This parameter change enables more effective gas removal during evacuation, resolving the contradiction between thorough gas removal and processing time efficiency.
2Productivity
If high processing loads are applied during lamination, then the lamination process is accelerated, but fragile silicon solar cells may be damaged
Solution Approach 1:
The adhesive layer is preheated to a softening state before the application of high processing loads. This preliminary softening action prepares the adhesive to flow and distribute evenly under pressure, allowing high loads to be applied safely without damaging the solar cells, thus accelerating the lamination process while protecting fragile components.
Solution Approach 2:
The patent applies a preliminary load phase at lower pressure before the main high-load lamination phase. This cushioning approach allows the softened adhesive to initially support the structure, providing protection for the solar cells when the higher loads are subsequently applied, thereby enabling faster processing without damage.
3Productivity
If the adhesive layer is heated to activation temperature before evacuation, then the lamination process can proceed, but gas bubbles form and compromise the work piece quality
Solution Approach 1:
The work piece is heated to a temperature that softens the adhesive layer but remains below the activation temperature at which significant gas generation occurs. This preliminary heating prepares the adhesive for lamination while avoiding the harmful effect of premature gas formation, maintaining both processing efficiency and work piece quality.
Solution Approach 2:
The patent precisely controls the temperature parameter during the preheating phase, maintaining it within a specific range where the adhesive softens sufficiently for lamination but does not reach the activation temperature that would cause excessive gas generation. This parameter control resolves the contradiction between processing efficiency and quality.
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 significantly reduces bubble formation, enhances the quality of laminated modules, and significantly shortens the processing time in the vacuum lamination press, allowing for faster completion of the lamination process without risking damage to the solar cells, and enables further curing in a subsequent laminator or curing kiln.
Implementation Method 1
The process heat required for the lamination process is usually transferred into the work piece by the bottom of the vacuum chamber which is embodied as a heating plate
Implementation Method 2
the vacuum chamber is evacuated and the compression means is pressed against the work piece by way of ventilating and/or impinging with pressure
Data Source
AI summary
A method for laminating essentially plate-shaped work pieces with a thermally activated adhesive layer, particularly photovoltaic modules. Work pieces are inserted into a vacuum chamber having a compression element dividing the vacuum chamber in a gas tight fashion that can be raised and lowered by pressure differences. The compression element presses against the work piece which in turn presses against a heating plate which forms a lower side of the vacuum chamber, with processing heat being transferred into the work piece to soften the adhesive. The work piece is first impinged by the compression element with a slight load from approx. 2% to 10% of the defined processing load, and is simultaneously kept below the adhesive activation temperature. Thereafter, the slight load is lifted off the work piece and the work piece is heated to the activation temperature and impinged via the compression element with the processing load.