Femtosekundenlaser lösen das Recyclingproblem von Solarmodulen. Durch Glasschweißen werden PV-Module versiegelt, ohne dass störende Polymere erforderlich sind.

>Solar panels are built to last 25 years or more in all kinds of weather. Key to this longevity is a tight seal of the photovoltaic materials. Manufacturers achieve the seal by laminating a panel’s silicon cells with polymer sheets between glass panes. But the sticky polymer is hard to separate from the silicon cells at the end of a solar panel’s life, making recycling the materials more difficult.

>Researchers at the U.S. National Renewable Energy Lab (NREL) in Golden, Colorado say they’ve found a better way to seal solar modules. Using a femtosecond laser, the researchers welded together solar panel glass without the use of polymers such as ethylene vinyl acetate. These glass-to-glass precision welds are strong enough for outdoor solar panels, and are better at keeping out corrosive moisture, the researchers say.

>“Solar panels are not easily recycled,” says David Young, a senior scientist at NREL. “There are companies that are doing it now, but it’s a tricky play between cost and benefit, and most of the problem is with the polymers.” With no adhesive polymers involved, recycling facilities can more easily separate and reuse the valuable materials in solar panels such as silicon, silver, copper, and glass.

>Because of the polymer problem, many recycling facilities just trash the polymer-covered silicon cells, and only recover the aluminum frames and glass encasements, says Silvana Ovaitt, a photovoltaic (PV) analyst at NREL. This partial recycling wastes the most valuable materials in the modules.