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Solar Cells Power Legal Fights

As the photovoltaic industry matures, competitors initiate expensive legal challenges

by Jean-François Tremblay
October 15, 2012 | A version of this story appeared in Volume 90, Issue 42

Credit: DuPont
DuPont’s solar R&D includes work at the firm’s photovoltaic center in Taoyuan, Taiwan.
Researchers at DuPont’s photovoltaic lab in Taiwan.
Credit: DuPont
DuPont’s solar R&D includes work at the firm’s photovoltaic center in Taoyuan, Taiwan.

In June, DuPont initiated a patent lawsuit against Germany’s Heraeus, its main competitor in the market for metallization pastes used to make photovoltaic solar cells. The lawsuit also accused SolarWorld Industries America of infringing DuPont’s intellectual property (IP) by using Heraeus materials in the production of solar cells.

After launching the lawsuit, DuPont issued a warning to others. At a conference in Shanghai, Walt Cheng, DuPont’s managing director for electronics and communications in China and Taiwan, declared that the company will “pursue vigorously other points in the photovoltaics supply chain where IP infringement of our photovoltaic metallization pastes exists.” The firm even issued a press release about the speech.

DuPont’s moves demonstrate that the solar industry has become a large enough market for chemical makers to justify the considerable expense involved with legal actions. When the solar market was younger and smaller, patent infringement could not inflict much damage on an industry giant such as DuPont. But now, the outcome of a patent lawsuit could result in billions of dollars of additional or lost sales.

“Going to court is very costly, so the business has to be big enough to warrant it,” Cheng tells C&EN in his office in Shanghai. “We don’t like taking people to court, but we will have no choice but to sue those who infringe on our intellectual property.”

Technological advances from firms such as DuPont are largely to thank for the increasing size of the solar energy market, Cheng adds. Solar-cell prices are constantly dropping even as the units become more efficient at generating electricity. “Solar energy is now only a small portion of the total energy mix, but it has huge potential,” he says. “The sun is everywhere, and solar cells are portable.”

The lawsuit DuPont initiated against Heraeus this summer is its second against the German firm. A case that was launched in 2011 is ongoing. In both instances, DuPont says Heraeus copied key elements of its Solamet line of metallization pastes, which conduct electricity in solar cells. “We have made a step change in the chemistry of metallization pastes,” Cheng says. “It’s DuPont technology that enables efficient manufacturing of solar cells by screen printing.”

DuPont has been investing in solar R&D since the early days of the industry, Cheng adds. “Our competitors are welcome to use our technology if they agree to a licensing fee,” he says.

Both Heraeus and SolarWorld, also a German firm, deny any wrongdoing. In a statement issued in July, Heraeus said it reviewed the two DuPont patents in question and concluded that it does not infringe any valid claim of either one. “DuPont’s patent lawsuits seek to achieve through legal means what they cannot achieve through product performance and customer service,” the statement said. Heraeus added that it invests heavily in R&D and has thousands of patents of its own.

As for SolarWorld, it tells C&EN that the DuPont case makes no sense. The claim “was surprising for us and hardly comprehensible,” the firm says. DuPont filed the suit in Oregon, where SolarWorld has its U.S. headquarters and operates the largest U.S. solar panel plant.

Whether Heraeus is guilty of patent infringement has little to do with SolarWorld, the cell maker says, because it merely purchased metallization pastes from Heraeus. But DuPont claims that it was financially harmed by SolarWorld’s sale of solar cells made with patent-infringing pastes. The U.S. firm demands compensation for lost profits and the payment of a license fee.

Interestingly, SolarWorld and DuPont find themselves on opposite sides of another dispute involving solar cells. SolarWorld has lobbied the European Union and the U.S. International Trade Commission to slap antidumping duties on Chinese-made solar cells.

DuPont, meanwhile, does not support the trade restrictions. It has major customers for its materials in China with which it codevelops products. Among DuPont’s key customers are Yingli Green Energy and Suntech, two of the world’s largest producers of solar cells. SolarWorld tells C&EN that it “cannot presume” that the company’s position on punitive tariffs was a factor in DuPont’s decision to launch the patent infringement lawsuit.

DuPont materials play an important role in the Chinese solar industry by providing legitimacy to Chinese-made solar cells in foreign markets, says Fatima Toor, an analyst who heads solar component coverage at the consulting firm Lux Research. For instance, companies that build solar farms in the U.S. typically agree to buy solar cells made in China only if they are made with DuPont materials, she says, because such cells are perceived to last longer than those made with materials from Chinese companies. Polyvinyl fluoride film is another key DuPont product for the solar industry.

Concerning the patent cases involving DuPont, Heraeus, and SolarWorld, the courts are likely to find the arguments and evidence presented murky, Toor adds. “It’s difficult to decide who is right,” she says, noting that she has read the relevant DuPont patents. “There are a lot of components in the metallization paste such as silver powder and organic elements, and it’s tricky to gain the expertise to make it. But at the same time, patents are usually written vaguely in an effort to cover all angles.”

Although it is suing non-Chinese competitors, it makes sense that DuPont chose a conference in Shanghai to proclaim its commitment to IP protection in the solar industry, Toor says. Suppliers of materials and equipment to the solar industry are becoming increasingly concerned about patent infringement by Chinese manufacturers.

The concern is more acute among suppliers of machinery used to make photovoltaic cells than among materials firms, she says. “It’s difficult to protect IP on equipment because you cannot walk into somebody’s photovoltaic production facility or an equipment manufacturer facility and decide that the equipment is identical,” Toor says. As a result, she adds, some equipment manufacturers prefer not to patent their machines because patents are published.

The DuPont case is likely to be the first of many IP infringement cases that involve companies around the world, Toor says. “The solar industry is becoming just as concerned about intellectual property as the electronics industry is,” she says. The good news for everybody else is that the lawsuits are a product of the increased viability of solar power.


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