Laser-Welded Glass PV Modules Without Encapsulant Degradation
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Solution Overview
Problem
Current photovoltaic (PV) modules face challenges in efficiency, cost, and durability, particularly due to long manufacturing times, polymer-based encapsulant degradation, the need for aluminum frames, and poor optical coupling to cells.
Innovation Solution
The use of femtosecond (fs) lasers to create glass/glass welds, which hermetically encapsulate photovoltaic devices, reducing manufacturing time and costs, increasing cell life by eliminating encapsulant failure, and enhancing optical properties for improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vacuum lamination is used to encapsulate photovoltaic modules, then hermetic sealing is achieved, but manufacturing time increases to ~12 min/cycle
Solution Approach 1:
The patent replaces the mechanical vacuum lamination process with laser welding technology. The laser welding system uses optical energy to melt and fuse glass edges, creating hermetic seals without requiring vacuum equipment or lamination mechanisms. This substitution of mechanical systems with optical/thermal processes achieves hermetic sealing while dramatically reducing manufacturing cycle time from 12 minutes to seconds per module.
Solution Approach 2:
The patent changes the physical parameters of the sealing process by using laser welding instead of vacuum lamination. The laser welding process operates at much higher temperatures locally (melting point of glass) but for shorter durations, whereas vacuum lamination operates at lower temperatures for extended periods. This parameter change enables faster production while maintaining seal integrity.
2Reliability
If polymer-based encapsulants are used to seal photovoltaic modules, then sealing is achieved, but degradation occurs over time reducing cell life
Solution Approach 1:
The patent changes the material parameter from polymer-based encapsulants to glass materials. Glass is inorganic, chemically stable, and does not degrade like polymers do over time. The laser welding process creates hermetic seals between glass pieces that maintain their sealing properties indefinitely, eliminating the degradation issue associated with polymer encapsulants and thereby extending cell life.
Solution Approach 2:
The patent uses glass as both the encapsulating material and the sealing material, creating a composite glass-glass-welded structure. This eliminates the need for separate polymer encapsulant layers and creates a unified, degradation-resistant system where the glass pieces are hermetically sealed together through laser welding, providing long-term protection for the photovoltaic cells.
3Strength
If aluminum frames are used to provide mechanical strength, then structural support is achieved, but cost and weight increase
Solution Approach 1:
The patent makes the glass pieces perform multiple functions: they serve as both the protective encapsulating cover and the structural frame simultaneously. The glass edges are laser welded to form rigid corners and edges that provide mechanical strength, eliminating the need for separate aluminum frames. This multi-functionality reduces material cost by removing the aluminum frame material while maintaining structural integrity.
Solution Approach 2:
The patent extracts and removes the aluminum frame component from the module structure. By using laser-welded glass edges to provide mechanical strength, the aluminum frame is completely eliminated. This extraction reduces both material cost (removing aluminum material) and weight (removing dense aluminum structure) while the glass-glass welds provide sufficient structural support for the module.
4Ease of manufacture
If conventional glass is used without optical features, then manufacturing is simple, but optical coupling to cells is poor reducing efficiency
Solution Approach 1:
The patent applies local optical features to specific regions of the glass pieces. The glass is manufactured with localized properties such as anti-reflective coatings on the inner surfaces, textured regions for light scattering, or patterned areas for optical coupling. These local quality modifications improve light management and cell efficiency without complicating the overall manufacturing process, as the optical features are integrated into the glass production or applied during the laser welding assembly.
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 results in reduced manufacturing costs, extended cell lifespan, and increased efficiency due to the elimination of polymer-based encapsulants and the use of glass as a mechanical frame, while also improving optical coupling and passing static load tests.
Implementation Method 1
Low-cost industrial lasers can be used to weld the two sheets of glass together to form a hermetic seal in a fraction of current lamination time
Implementation Method 2
Focused laser heating allows bending/welding of glass into a robust mechanical shape to eliminate the aluminum frame
Data Source
AI summary
Described herein are photovoltaic devices and methods which utilize femtosecond (fs) lasers to create a glass/glass weld, hermetically encapsulating photovoltaic devices that provide both reduced cost and increased cell life and efficiency. For example, glass/glass welds can reduce manufacturing time and costs, increase cell life by removing encapsulant failure which is a leading cause of cell degradation and provide for increased optical properties, which improves cell efficiency.