Dow Chemical Co. (Midland, MI) is launching a line of polyolefin-based encapsulant films for photovoltaic (PV) modules, after adding a new production line at its Findlay, OH manufacturing plant for the new product in response to growing demand for PV specialty films. Dow says that compared to traditional ethylene-vinyl acetate (EVA) encapsulants, its Enlight polyolefin-based product can enhance PV module production efficiencies, for lower conversion costs, while also providing greater module stability and improved electrical performance.
The encapsulant films, which are suitable for C-Si and thin-film modules, are also said to improve the reliability and extend the service life of PV technology.
The technology falls under Dow's Specialty Packaging & Films business, with Brij Sinha serving as that group's global business development leader. In a release, Sinha said Dow customers utilizing the Enlight films were able reduce cycle times by up to 30% while also extending the temperature window for lamination. Sinha said the customers also found that the film's physical properties virtually eliminated bubbles, reducing rejects, with damage to equipment and modules lessened because the process does not produce acetic acid.
Dow says its polyolefin-based encapsulant films offer:
- WVTR’s 10-20 times lower than EVA
- Excellent adhesion to glass under various lamination conditions
- No creep in use
- Better matched refractive index to glass compared to EVA
- UL-listed Recognized Components
Production will initially occur at Dow's manufacturing plant in Findlay, with commercial-scale manufacturing to begin on the new line in the fourth quarter of 2010. Dow has a phase-in plan in place to upgrade production and increase capacity across the globe to address increasing demand for these differentiated encapsulants. Dow described its capital outlay in photovoltaic encapsulants thus far as a "multi-million dollar investment."
Enlight joins Dow's family of encapsulants, metallization, imaging, cleaning, and texturizing materials for the photovoltaic market. Products currently in the portfolio include Adcote solvent-based adhesives and Mor-Free solventless adhesives.
Traditionally, thin-film solar cell encapsulation utilizes a vacuum-lamination process between the encapsulating polymer, typically EVA and a second sheet of glass. According to Germany's Fraunhofer Institute research center, some disadvantages of this technology are the higher weight and gap between the two sheets of glass at the edges, where moisture and gas can enter into the photoactive layers and cause degradation. Fraunhofer also noted that the process can not be easily automated and requires a great deal of time, energy, and material. —[email protected]