02 Jun 2011
New structure and a laser-fired rear contact deliver efficiency improvement of more than 1% on company's previous best.
Ahead of the major InterSolar trade show in Germany next week, top-ten solar cell producer Q-Cells says that it has developed a 19.5% efficiency polysilicon cell based on a new back-side structure.
The advance builds on Q-Cells’ existing Q.ANTUM cell concept, and the performance of the 243 cm2 cell has been verified in tests at the Fraunhofer Institute for Solar Energy Systems (ISE).
According to Peter Waver, SVP of Technology at the Bitterfeld-Wolfen company, there is still more room for improvement: “We will further optimize this technology to achieve efficiencies of more than 20%,” he said.
The cell features a new back-side structure that combines dielectric layers and local laser-fired contacts, instead of the completely aluminum-metallized structure used currently. According to Q-Cells, this improves both the optical and electrical characteristics of the cell.
Based on the performance of modules based on Q-Cells’ previous best silicon cells, which were tested by the European Solar Test Installation (ESTI) earlier this year, the new result suggests a likely peak output of around 283 W for a module with a 1.5 m2 aperture area if the performance can be replicated in volume production.
That compares with Q-Cells’ existing commercial Q.BASE modules, which produce 215-230 W at peak, and Q.PRO modules that deliver 225-240 W. The company’s largest Q.SMART modules, which are based on thin-film CIGS photovoltaic material rather than silicon, produce 90-110 W peak from a 1 m2 surface area.
Last year, solar cell developers at IMEC in Belgium showed how relatively simple changes to cell production processes could deliver a crystalline silicon cell efficiency of 19.4%, and a pathway to 20%, although this related to the typically more expensive monocrystalline cell type.
Q-Cells says that its new development “opens up potential for further cost savings in the industrial production of solar cells”, although the price of cells depends heavily on the cost of the polysilicon feedstock from which the cells are produced.
Meanwhile Suntech Power, currently the world's largest solar panel manufacturer, has developed low-oxygen-content cells with a conversion efficiency of 18% by combining the higher efficiency of monocrystalline material with the better reliability of polysilicon wafers. 250 W modules incorporating the new technology will be on show at the InterSolar event, and begin shipping to Europe this month, according to the Chinese company.