Annual growth rates of 20%-plus are attracting injection molders to the photovoltaic industry. In order to drive costs down, solar panel manufacturers need to adopt high-throughput manufacturing systems. While most of the plastics action is in extruded sheet or film, injection molding also has a role to play in frames, and sometimes even in
sophisticated systems that focus and concentrate solar energy.
One example of the action is the recent announcement from Sabic Innovative Plastics of an extension of tis photovoltaic portfolio. A new high-performance Lexan EXL copolymer resin addresses the fast-moving trend toward miniaturization of photovoltaic (PV) connectors and junction boxes. Lexan EXL is a polycarbonate copolymer formulation that offers superior impact and low temperature ductility compared to standard PC grades.
Miniaturization is one trend in PV. Another is concentration, which uses mirrors or lenses to focus light onto an area as small as 1 cm² (0.16 inch²) of active semiconductor PV material. These systems show conversion efficiencies of better than 36%.
Concentración Solar La Mancha of Manzanares, Spain, developed a concentrated photovoltaic module consisting of six concentrator elements that automatically track the sun’s movement across sky. They are built into a frame injection molded from a mica- and glass-reinforced grade of DuPont Rynite polyethylene terephthalate (PET), which was used instead of powder-coated aluminum.
Miguel Trinidad Aragon, CEO of Concentración Solar La Mancha, says: “We were clear from the outset that we wanted to replace metal with a high performance polymer due to the benefits associated with the change, including corrosion resistance, design flexibility and lower processing cost and material costs. Through the integration of additional functions in the housing, we were able to reduce the number of manufacturing steps.”
The potential for molding is much greater, argue engineers from Phillips High Tech Plastics in Veldhoven, the Netherlands, and a Finnish research center in a paper titled: “How can plastics injection molding help drive down the cost of photovoltaic concentrators?” They point to the migration of the CD/DVD industry to high-speed injection molding machines as an example of how Fresnel lens molding for PV concentrators could proceed.