NREL Proof of Concept Shows Path to Easier Recycling of Solar Modules

The use of a laser to weld the edges of glass together can help make solar panels easier to recycle at the end of their lifespan. Graphic by Al Hicks
Photo source
The use of a laser to weld the edges of glass together can help make solar panels easier to recycle at the end of their lifespan. Graphic by Al Hicks

Date: 2 May 2024

Use of Lasers To Melt Edges of Glass Together Eliminates Troublesome Polymers

The use of femtosecond lasers to form glass-to-glass welds for solar modules would make the panels easier to recycle, according to a proof-of-concept study conducted by researchers at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL).

The welds would eliminate the need for plastic polymer sheets that are now laminated into solar modules but make recycling more difficult. At the end of their useful lifespan, the modules made with the laser welds can be shattered. The glass and metal wires running through the solar cells can be easily recycled and the silicon can be reused.

“Most recyclers will confirm that the polymers are the main issue in terms of inhibiting the process of recycling,” said David Young, senior scientist and group manager for the High-Efficiency Crystalline Photovoltaics group in the Chemistry and Nanoscience department at NREL. Young is lead author of a new paper outlining the use of laser welds for solar modules. The paper, “Towards Polymer-Free, Femto-Second Laser-Welded Glass/Glass Solar Modules,” appears in the IEEE Journal of Photovoltaics.

Written with NREL colleagues Tim Silverman, Nicholas Irvin, and Nick Bosco, the paper also counts as its coauthors two employees of Trumpf Inc., the California company that made the femtosecond laser involved. A femtosecond laser uses a short pulse of infrared light that melts the glass together to form a strong, hermetic seal.

The glass weld can be used on any type of solar technology—silicon, perovskites, cadmium telluride—because the heat of the weld is confined to a few millimeters from the laser focus.

Solar modules are made of semiconductors designed to capture a specific portion of the solar spectrum, harnessing sunlight to create electricity. Typically, the semiconductors are sandwiched between two sheets of glass laminated together with polymer sheets.

NREL’s research showed that femtosecond laser, glass/glass welds are essentially as strong as the glass itself.

“As long as the glass doesn’t break, the weld is not going to break,” he said. “However, not having the polymers between the sheets of glass requires welded modules to be much stiffer. Our paper showed that with proper mounting and a modification to the embossed features of the rolled glass, a welded module can be made stiff enough to pass static load testing.”

NREL’s research is the first to use a femtosecond laser to form glass/glass welds for use in a module. A different type of edge sealing using nanosecond lasers and a glass frit filler was tried in the past, but the welds proved too brittle for use in outdoor module designs. The femtosecond laser welds offer superior strength with hermetic sealing at a compelling cost.

Young said the research is “definitely high risk, high reward,” but points to a direction for further research to extend the life of solar modules to beyond 50 years and to allow easier recycling.

This research was done through the Durable Module Materials Consortium, which is led by NREL and funded through the U.S. Department of Energy's Solar Energy Technologies Office in the Office of Energy Efficiency and Renewable Energy

NREL is the U.S. Department of Energy's primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for DOE by the Alliance for Sustainable Energy LLC.

600450 NREL Proof of Concept Shows Path to Easier Recycling of Solar Modules

Others also read

As Penn State’s first ground-up building in downtown State College, Pa., the new LEED® Gold-targeting Eric J. Barron Innovation Hub, formerly known as the James Building, maximizes daylighting with precisely sized openings and a ground-floor curtainwall system.
Thermoseal Group has invested in a new recycling plant that will reduce the amount of manufacturing waste going to landfill.
In the intricate world of glass manufacturing, precision, and quality assurance stand as pillars of success.
As part of AYD Group Glass Industry, Wenfrod reinforces its leadership position in the industry through innovative products and sustainable business models.
EPPA participated at the event organized by the European Commission’s DG GROW (the Directorate-General for Internal Market, Industry, Entrepreneurship and SMEs).
Şişecam, among the world's top five largest global manufacturers in the Flat Glass sector, participated in the International Solar Energy and Technologies Fair, Solarex Istanbul, held at the Istanbul Fair Center.

Add new comment

From industry

İçmeler Mah. D-100 Karayolu Cad. No:44A,
34947 Tuzla,/İstanbul


Wenfrod Glass Processing Co. (Tempered Glass Factory Turkey)
Shenzhen Gaoren Electronic New Material Co. Ltd
Unelko Corporation