Flat-die maker Extrusion Dies Industries LLC has picked up work from the solar power industry, including an advanced reel-to-reel method of applying thin films to make the photovoltaic panels.
EDI, of Chippewa Falls, Wis., is pushing this new continuous production as a way to reduce the manufacturing cost, and turn out high volumes of flexible solar electric systems.
Usually, the thin-film solar production lines require between seven and 11 layers of film, and they include multiple stations for coating, curing and drying each layer, said Mark Miller, manager of EDI's market development group.
``One of the ultimate goals of thin-film solar technology, for example, is to produce photovoltaic film in large quantities of roll stock that can be sold to general contractors for installation atop houses and commercial buildings,'' Miller wrote in a technical paper.
Miller said the company considers solar a growth area for its dies, and for the overall plastics industry. EDI already has sold dies into the solar power market used in both the conventional rigid solar panels and the new thin-film panel-making process, he said, but he declined to give any details.
``We want to help the existing market,'' Miller said. ``But our strategy is to concentrate on the future.''
Alternative power such as solar, wind and plant-based energy should fare well in the new administration of President Barack Obama. Obama mentioned them in his Jan. 20 inaugural address.
Extrusion Dies touted its coating abilities for solar power at last year's Converting & Package Printing Expo in Chicago. Miller said EDI officials plan to attend major solar power trade shows in the U.S. and in Germany, a leading nation in alternative energy.
EDI is touting its Liberty slot- die coating systems picked up when EDI bought Liberty Coating Equipment in 2007 and its Contour cast-film dies for solar panel production.
Traditional solar panels are covered with a top layer of glass or plastic. Inner layers are solar cells and a conductive layer that closes the electrical circuit, according to Miller's technical paper. The solar cells are made in a batch process, using technology from the semiconductor industry. That includes slicing crystalline silicon into wafers.
To serve that conventional solar market, EDI's slot dies can do patch coating intermittently applying the coating materials.
But doing continuous production of thin-film solar systems can turn out flexible products that exploit precision multilayer technology of EDI's flat dies and feed blocks, Miller said. Two EDI innovations fit here, the company said:
* ``Lane coating'' uses Liberty slot dies to apply conductive slurries in continuous lanes, alternating with uncoated lanes. EDI also has developed dies that simultaneously can coat two sides of a substrate with up to 48 separate lanes. Slot-die coating is used to apply fluids intermittently to continuous web substrates. Miller said slot-die coating is a key to making lithium-ion batteries.
* For making ``microlayer film,'' EDI outfits its Contour cast-film dies with a new system, based on technology from Dow Chemical Co., that can produce film of standard thickness but with dozens of very thin microlayers. According to EDI, these multiple layer-to-layer interfaces substantially increase the barrier properties of the film against infiltration by oxygen and moisture, which is critical for photovoltaic applications.
Several years ago, EDI received funding from the U.S. government to develop a process to produce lower-cost films for rechargeable batteries that power portable electronic devices for soldiers. Miller said that EDI is working on another military project to create improved barrier packaging for food rations.