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New DuPont Encapsulant Makes W&K Solar Modules Simpler, Stronger and Faster to Manufacture

Ionomer-Based DuPont™ PV5400 Series Encapsulant Helps Trim a Manufacturing Step

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WILMINGTON, Del., Aug. 25, 2011 -- Willard and Kelsey (W&K) Solar Group announces commercialization of their new "WK1-75" photovoltaic (PV) module using DuPont PV5400 Series encapsulant.  Designed for utility-scale clean energy projects, the new module incorporates a cost-effective cadmium-telluride (CdTe) thin-film power-generating layer, which is given extra protection by the new, highly moisture-resistant DuPont™ PV5400 ionomer-based PV encapsulant.

"Builders and investors in solar farms look at total lifetime energy return per dollar spent," explains Keith Guenther, director of product development for W&K Solar. "CdTe-based thin-film photovoltaic modules convert photons into electricity as much as 20 percent more efficiently than typical amorphous silicon modules.  But with any module, the key to long-term output efficiency is resistance to extreme weathering, and especially resistance to moisture intrusion at the module edges."

"When used in our durable new WK1-75 frameless modules, DuPont PV5400 Series encapsulant blocks moisture ingress better than any other encapsulant tested," said Guenther. "The protection is so much better, it eliminates the need for edge seals."

To block moisture ingress at the edges of conventional modules, manufacturers often need to add an edge seal, increasing material and labor costs to help mitigate the inherent moisture susceptibility of traditional encapsulants. Using more moisture-resistant DuPont PV5400 Series encapsulant, with no edge seal, W&K Solar modules are able to achieve durability well beyond what's required by current standards.  For example, in "damp heat" testing conducted in accordance with IEC 61646 Section 10.13, the new W&K module survived more than 4,000 hours versus the required 1,000 hours required for acceptance.

DuPont worked closely with W&K Solar to advise on ionomer sheet processing techniques and testing protocols for the new module.  "DuPont basically became part of our development team," said Guenther.

Because it is up to 100 times stiffer and 5 times stronger than traditional thin film laminating materials, DuPont PV5400 encapsulant also improves module deflection resistance and mechanical strength. Laminating speeds with the new encapsulant are increased by as much as 30 percent versus using traditional PVB- and EVA-based encapsulants.

Ionomer-based PV5400 Series encapsulant is supplied by DuPont in roll form as ready-to-use sheeting up to 160 cm wide, in thicknesses from 0.40 to 0.50 mm. The encapsulant is processed using the same equipment used for traditional modules.

W&K Solar's new 75-watt module is an attractive, open-edged, 60 by 120 cm laminated power-generating panel that can be mounted onto large-scale arrays using a variety of fixturing methods. For more information about W&K Solar, visit

DuPont™ photovoltaic encapsulants are part of a broad and growing portfolio of products represented by DuPont Photovoltaic Solutions (DPVS), which connects science and technology from across the company on a global scale to help support the dramatic growth in the photovoltaic industry.  To learn more, please visit.

DuPont (NYSE: DD) has been bringing world-class science and engineering to the global marketplace in the form of innovative products, materials, and services since 1802.  The company believes that by collaborating with customers, governments, NGOs, and thought leaders we can help find solutions to such global challenges as providing enough healthy food for people everywhere, decreasing dependence on fossil fuels, and protecting life and the environment.  For additional information about DuPont and its commitment to inclusive innovation, please visit

WK1-75 module is a laminated glass-glass cadmium-telluride structure using clear DuPont(tm) PV5400 Series photovoltaic encapsulant.
Willard & Kelsey Solar Group’s new frameless WK1-75 module is a laminated glass-glass cadmium-telluride structure using clear DuPont™ PV5400 Series photovoltaic encapsulant. The 75-watt module measures 1200 mm by 600 mm and weighs just 26 pounds, with a total thickness of 6.4 mm. (high resolution image
W&K Solar Group has passed more than 4000 hours of damp heat testing without the need for a secondary edge seal
Thanks to DuPont™ PV5400 Series photovoltaic encapsulant, the new WK1-75 frameless thin film solar module by W&K Solar Group has passed more than 4000 hours of damp heat testing without the need for a secondary edge seal. (high resolution image)

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