Recently, scientists at the Fraunhofer ISE Institute for Solar Energy Research in Germany have developed a new laser technology that reduces the amount of silver used in solar panel production and achieves extremely high module efficiency using thin aluminum foil.
In the new technology, dubbed "FoilMet," the Fraunhofer ISE researchers use a thin layer of aluminum foil to connect adjacent solar cells in a module. The team observed that the process took less than a tenth of a second for each crystalline silicon cell to connect. The scientists used a unique laser microwelding mechanism to attach the aluminium film to the conductor's path, while connecting it to the surface of the silicon nitride in the middle region.
Since there is no need to use conductive adhesives (electroglue) or welding techniques to connect the batteries, this connection solution using laser aluminum foil saves resources -- silver consumption is reduced by 30%. And because the contact resistance between the film and the electrode is very low, higher efficiency is generated in the solar module part of the experiment.
Currently, the team has also successfully implemented a potential replacement for copper connectors using aluminum as a leaded solder or silver binder.
According to the introduction, the string design adopted in the experiment is curved. Mechanical flexible connections not only enable flexible bending design of strings, but can also be arranged as imbricated cells to achieve maximum component efficiency.
Researchers around the world are now studying the use and problems of silver in solar module manufacturing, which has raised concerns about the interconnection of solar cells. The solid mechanical adhesion the Fraunhofer ISE scientists deployed in their module exceeded the foil's potential, and the laser foil helped the team create interconnections in the tile structure, where the solar cells overlap slightly as they approach each other.
Overall, according to Fraunhofer ISE scientists, "FoilMet" technology is cost-effective for mass production of solar panels that can maintain higher efficiency.
Jan Nekarda, head of structure and metallization at Fraunhofer ISE, notes, "The beauty of our technology is that it improves module efficiency and aesthetics due to low resistance. The tile structure combined with the very high mechanical flexibility of the connection is destined to be a successful niche application for integrated photovoltaics. On the other hand, the huge potential for cost and material savings makes this process even more meaningful for the PV mass market."
Researchers around the globe are conducting experiments to discover potential substitutes for silver in solar panels. After all, metals like silver, indium and bismuth are scarce on Earth. According to a report by researchers at the University of New South Wales Institute of Photovoltaic Renewable Energy and Engineering (SPREE), this scarcity is likely to hinder sustainable production of photovoltaics on a scale of several terawatts.
In February 2022, Fraunhofer ISE scientists teamed up with researchers at the Fraunhofer Center for Silicon PV and Reiling GmBH, a German solar module recycler, to develop a method for recycling waste solar modules. Eventually, the team of scientists will recycle wafers made from silicon into PERC solar cells, which have a conversion efficiency of 19.7 percent.
Source: OFweek
