Climate Insider Brief:
- Researchers at NREL have demonstrated a novel method for simplifying the recycling process of solar modules.
- By using femtosecond lasers to create glass-to-glass welds, they eliminate the need for polymer sheets, thus overcoming a significant obstacle in conventional recycling methods.
- The use of femtosecond lasers offers several advantages, including creating strong and hermetic seals between glass layers.
A recent proof-of-concept study conducted by researchers at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) has revealed a promising method to simplify the recycling process of solar modules. Utilising femtosecond lasers to form glass-to-glass welds, the study suggests a significant advancement in addressing the challenges associated with solar module recycling.
The conventional approach to solar module construction involves laminating semiconductors between two sheets of glass using plastic polymer sheets. However, these polymer sheets pose a significant obstacle to recycling efforts. At the end of their lifecycle, current solar modules require complex disassembly processes to separate and recycle the various materials.
The research conducted by NREL proposes an alternative solution by employing femtosecond lasers to create glass-to-glass welds, eliminating the need for polymer sheets. This innovative technique allows for the easy disassembly of solar modules by shattering them. Consequently, the glass and metal wires present in the modules can be readily recycled, while the silicon components can be reused.
David Young, senior scientist and group manager for the High-Efficiency Crystalline Photovoltaics group at NREL, highlights the significance of this approach, stating, “Most recyclers will confirm that the polymers are the main issue in terms of inhibiting the process of recycling.” The findings of this research are detailed in a paper titled “Towards Polymer-Free, Femto-Second Laser-Welded Glass/Glass Solar Modules,” published in the IEEE Journal of Photovoltaics.
The use of femtosecond lasers offers several advantages. These lasers deliver a short pulse of infrared light, melting the glass together to form a strong and hermetic seal. Importantly, the welds exhibit strength comparable to that of the glass itself, ensuring durability and reliability. Furthermore, the technique can be applied across various solar technologies, including silicon, perovskites, and cadmium telluride.
While acknowledging the high-risk nature of the research, Young emphasises its potential rewards. He notes that this advancement could pave the way for extending the lifespan of solar modules beyond 50 years and streamlining the recycling process.
The study was conducted as part of the Durable Module Materials Consortium, led by NREL and funded by the U.S. Department of Energy’s Solar Energy Technologies Office. This initiative underscores NREL’s commitment to advancing renewable energy and energy efficiency research and development.
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