The suit, filed in federal court in Portland, Oregon, is over a conductive paste that coats the front side of a solar cell. The paste is made by a unit of Heraeus Holding GmbH and supplied to SolarWorld’s U.S. unit, according to the complaint.
Solar panels are made of silicon wafers coated with a paste made with silver, which helps conduct the electricity, and other things like glass frit and resin. DuPont, whose materials are in 70 percent of the world’s installed panels, said the patent issued in April covers a composition with improved electrical performance.
Making solar panels more efficient, and thus reducing the cost, is necessary to make the alternative energy more competitive with fossil fuels. Solar-cell prices have fallen more than 55 percent in the past year. Silver prices, which have soared over the past two years, have hampered efforts to reduce the costs further because each panel contains about 20 grams of the metal.
Ben Santarris, a spokesman for SolarWorld, said the company had no immediate comment.
DuPont sued Hanau, Germany-based Heraeus last year over a different patent for a conductive paste. That case is pending in federal court in Wilmington, Delaware, where DuPont is based.
DuPont and Bonn, Germany-based SolarWorld have been on opposite sides of a trade fight over solar panels made in China. A group including SolarWorld’s U.S. unit filed a complaint last year claiming the Chinese government was providing unfair subsidies to panel manufacturers in that country. The U.S. Commerce Department imposed duties on panels imported from China, and a similar complaint is being discussed in Europe.
DuPont is part of the Global Solar Council, a lobbying group formed in May to promote an open trading system.
The case is E.I. DuPont De Nemours & Co. v. Heraeus Materials Technology LLC, 12cv1104, U.S. District Court for the District of Oregon (Portland)