Metallization

Researchers from Germany’s Fraunhofer ISE developed new techniques to reduce silver consumption in tandem perovskite silicon solar cells and heterojunction silicon PV devices. The new processes relate to cell metallization and module interconnection.

China’s Solamet has launched a new silver paste product for tunnel oxide passivated contact (TOPCon) solar cells processed with laser carrier injection technology. By solving a problem related to contact between the paste and the boron doped front surface of the silicon cell, it promises an efficiency improvement of at least 0.2% over competing products.

pv magazine speaks with Matthew Watson, president of Precious Metals Commodity Management LLC, about silver demand and availability. He says the solar industry has managed to reduce silver consumption, but it may have to do more in the future.

Michael DiRienzo, executive director of The Silver Institute, tells pv magazine that average silver prices will hover around $23 per ounce this year, without any anticipated supply disruptions for the solar industry.

Germany’s Fraunhofer ISE is applying its FlexTrail-printing technology to the direct metallization of silicon heterojunction solar cells. It said the technique reduces the use of silver, while maintaining high efficiency levels.

Scientists from the Fraunhofer ISE built a bifacial heterojunction solar cell with a power conversion efficiency of 21.7% via rotary screen printing. They used a machine that is able to achieve a cycle time of just 0.6 seconds per solar cell and enables a strong reduction in silver use.

Developed by Germany’s Fraunhofer Institute for Solar Energy Systems ISE and ASYS Automatisierungssysteme GmbH, the new machine is claimed to increase the print process throughput by a factor of 1.5.

According to the Silver Institute, global industrial silver demand is expected to grow 8% this year due to strong demand in all key sectors, including the PV industry.

Developed by a U.S.-based start-up, the new manufacturing process is claimed to reduce silver consumption and improve solar module performance by up to 3 W. It consists of connecting sub-cells in series within a single cell in order to increase the device voltage and without requiring cells to be physically broken and rewired.

Scientists in Germany investigated various routes to optimizing cell design for perovskite-silicon tandem products. Beyond the perovskite layer itself, they note several other areas that should be optimized for tandem cells, taking silicon heterojunction processing as a starting point. The research identifies several routes to cut costs in cell production, including a significant reduction in indium consumption.