“Most recyclers will confirm that the polymers are the main issue in terms of inhibiting the process of recycling,” David Young, lead author of the article, said in a media statement.
Femtosecond laser
To carry out their experiment, the scientists employed a femtosecond laser which uses a short pulse of infrared light that melts glass together to form a strong, hermetic seal.
The glass weld can be used on any solar technology—silicon, perovskites, cadmium telluride—because the weld heat is confined to a few millimetres 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 with polymer sheets.
NREL’s research showed that 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,” Young 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.”
This research is the first to employ 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 study is “high risk, high reward,” but points to a direction for further research to extend the life of solar modules beyond 50 years and to allow easier recycling.
This post was originally published on 3rd party site mentioned in the title of this site
