Heraeus fighting to set new PERC performance record
HERAEUS' testing of their new SOL9620x series has shown 0.5 percent absolute efficiency gains on 90 Ω/sq. mono PERC wafers compared to the SOL9610. The SOL9620x achieves this in part due to lower recombination below the metallized contacts, resulting in an increase of the Voc of as much as 5 mV. The SOL962x series also has a 50 percent reduction in contact resistance compared to the SOL9610 series at a lower doping surface concentration. Improved performance of finger lines of SOL9620x together with non-firing through SOL325 busbar benefits overall PERC cell design performance, Andreas Liebheit, Head of Heraeus Photovoltaics, based in Shanghai, said recently that efficiency gains by the SOL9620x series should be attributed to continuing investment in R&D and partnerships with manufacturers as well as his company's abilities to continually customize and refine products for specific applications. This process is critical to PERC performance improvements.
"With the new products added to our successful SOL9620x Series of front-side pastes, combined with our SOL325 Series for busbars, we believe that our partners and customers will have the ability to produce PERC cells with an even higher efficiency than with previous generations of pastes," Liebheit noted.
Are gains in efficiency enough to drive an interconnected global solar electricity generation market? While no one element can be singled out, industry watchers agree that efficiency is a key factor among conditions lining-up to make 2015 a banner year. Solar industry forecasters see continued growth in PV installations for 2015. Success for solar depends as much on cell efficiency, unit cost reductions and improved manufacturing techniques as it depended in the past upon government subsidies, utility-grade investments and green-minded consumers.
The United States is on pace to complete its one millionth solar system installation in 2015 according to the Solar Energy Industries Association and GTM Research. While highly significant, the US doesn't by itself make or break the global market since 50 percent of solar capacity in 2015 will be found in China and Japan, according to Bloomberg Energy Finance. Growth across Europe and new Sub Saharan Africa markets is expected to be significant despite the fact some EU nations are reducing subsidies that fuelled past solar technology gains.
Greater efficiency remains a key to solar's long-term success. Most economists and industry analysts agree that solar can only grow beyond a certain point if it is cost-competitive with other forms of electricity generation. PERC technology is inherently more efficient than traditional p type c-Si solar, usually by 1 percent absolute, yet the battle for "˜efficiency supremacy' is fought across many fronts.
Heraeus has formulated successive generations of silver paste that boost efficiency. As Liebheit explained, Heraeus sees its value when customers can use their products to increase the value of their cells and modules relative to next-best alternatives.
An efficiency gain impacts the entire value chain; it reduces the number of modules required for a given energy demand, thereby reducing the amount of poly-silicon, wafers, cells and the real-estate requirements for PV installations, not to mention the overall installation BOM.PERC manufacturers are already working with the latest generation of SOL9620x to create products that are now entering the retail market. Dr. Weiming Zhang of Heraeus Photovoltaics, said that while Heraeus believes their new product is enabling greater efficiency, outside facilities are testing to quantify that belief; results are expected to show gains that outpace those of competing products.
"PERC is a key solar cell technology for improving conversion efficiency as a means to reduce the cost of solar energy. Heraeus employees were proud that our pastes contributed to ISFH's record cell performance in 2014 using our SOL325 and SOL9610 Series. Though that record has been surpassed, this only increases our motivation to use technology and our know-how to create better solutions that solve our customers' greatest challenges," remarked Liebheit.
The battle for efficiency supremacy continues. While Heraeus and its competitors each hope they'll win, the fact there are such competitions shows that consumers and global markets are the real arbiters of success and the ultimate winners.
