Thermoplastic Solar Cell Interconnection via Melt Flow
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Solution Overview
Problem
Conventional solar cell panel manufacturing processes are bottlenecked by the need for long curing times in cross-linking processes, leading to reduced production output and increased costs due to batch processing and manual soldering, which constrains the flow of panels through laminating equipment.
Innovation Solution
A method involving melt flowable optically transparent and electrically insulating thermoplastics with conductive patterns for interconnecting solar cells, allowing for continuous heat laminating without cross-linking, enabling faster processing and reducing production time and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cross-linking process with extended curing time is used, then bond strength and reliability are improved, but production time and manufacturing cost increase
Solution Approach 1:
The patent changes the chemical parameters of the encapsulant material from cross-linking polymers (EVA, PO) to non-cross-linking thermoplastic polymers. This parameter change eliminates the need for extended curing time while maintaining bond strength through the thermoplastic melting and bonding mechanism during heat lamination.
Solution Approach 2:
The patent utilizes the phase transition of thermoplastic polymers from solid to molten state during heat lamination, allowing the encapsulant to flow and bond to solar cells and glass. Upon cooling, the material solidifies to provide structural support and electrical insulation without requiring chemical cross-linking.
2Reliability
If batch processing is used, then quality control is improved, but production output and throughput decrease
Solution Approach 1:
The patent enables continuous processing by eliminating the batch curing step. The heat lamination process continuously laminates solar cells, glass, and thermoplastic encapsulant through a laminating machine, with the thermoplastic bonding occurring continuously during the heating and cooling zones of the machine, allowing uninterrupted production flow.
3Reliability
If manual soldering is used, then connection reliability is improved, but manufacturing cost and processing time increase
Solution Approach 1:
The patent replaces the mechanical soldering process with a thermal bonding process using thermoplastic materials. The thermoplastic encapsulant melts during heat lamination to form electrical connections between conductive patterns on glass and solar cells, eliminating the need for manual or automated soldering equipment and operations.
Solution Approach 2:
The patent uses composite structures where thermoplastic polymer materials provide both mechanical bonding and electrical conductivity functions. The conductive thermoplastic composition combines insulating polymer matrix with conductive fillers to create a material that simultaneously bonds components and establishes electrical connections.
4Manufacturing precision
If vacuum lamination at elevated temperature and pressure is used, then encapsulation quality is improved, but equipment complexity and processing time increase
Solution Approach 1:
The patent changes the processing parameters by using thermoplastic materials that bond at lower temperatures compared to cross-linking materials. This reduces the required lamination temperature and eliminates the need for vacuum systems, simplifying the equipment to basic heating rollers and pressure application mechanisms.
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 solar cell panels with reduced processing time, increased efficiency, and lower costs by eliminating the need for extended curing times and manual soldering, allowing for higher throughput and improved manufacturing efficiency.
Implementation Method 1
a top layer of a melt flowed melt flowable optically transparent electrically insulating thermoplastic having a first pattern of melt flowable electrically conductive thermoplastic thereon
Implementation Method 2
the first patterns of melt flowable electrically conductive thermoplastic making electrical connection to the front surfaces of the plurality of solar cells
Data Source
AI summary
A laminated module or panel of solar cells and a laminating method for making same comprise a top layer of melt flowable optically transparent molecularly flexible thermoplastic and a rear sheet of melt flowable insulating molecularly flexible thermoplastic both melt flowing at a temperature between about 80° C. and 250° C. and having a low glass transition temperature. Solar cells are encapsulated by melt flowing the top layer and rear sheet, and electrical connections are provided between front and back contacts thereof. Light passing through the transparent top layer impinges upon the solar cells and the laminated module exhibits sufficient flexural modulus without cross-linking chemical curing. Electrical connections may be provided by melt flowable electrically conductive molecularly flexible thermoplastic adhesive or by metal strips or by both.