An Encapsulant for Every Application

In the early years of the photovoltaic (PV) industry, solar cells or "modules" were primarily based on mono-crystalline silicon. Today there are mono- and poly-crystalline modules and a variety of thin film technologies including amorphous silicon (a-Si), cadmium telluride (CdTe), Copper Indium Gallium Selenide (CIGS), and various cell constructs including organic dyes and nano-technology.

As photovoltaic technology developers move rapidly to capitalize on new science and breakthroughs, a variety of specialty chemical companies have increased development and introduction of modified materials that have been available for years.

This phenomenon is most evident in the encapsulant area of photovoltaics. Encapsulants simultaneously fuse a module together while protecting the module from the outside environment. Maintaining module integrity and module performance over rated useful life cycles is critical for module designers and manufacturers. Encapsulant providers are beginning to focus on developing products that reduce total module costs while enhancing module performance. These products can improve everything from panel efficiency to processing time and overall manufacturing yield.

There are a variety of encapsulants available for module designers. Many of these materials were originally developed for application in laminated windscreens and laminated architectural glass.

Polyvinyl Butyral (PVB), like Saflex^®, is gaining favor in certain segments of the photovoltaic market. PVB is typically provided to a module maker as a resin based sheet that can be trimmed to fit a given application. While it has been in use for decades in laminated glass applications, recent technology developments have made it a material of choice for certain PV module designs – including many thin film technologies. Further, PVB is an excellent choice for "Building Integrated Photovoltaic" (BIPV) applications due to its long history of use in the laminated architectural glass segment.

Changes in formulations over the last 20 years have made Saflex PVB an ideal fit for photovoltaic applications. The development of formulas with strong edge stability and chemical compatibility provide module designers with a material that improves both manufacturing processes as well as long term module durability. High yield, cost effective encapsulation processes –familiar to the glass lamination industry are now being used to encapsulate thin film amorphous modules. These processes, coupled with innovation in PVB, increase throughput, which drops the total cost per watt produced – a significant metric for module makers.

Encapsulants will continue to play a key role in the development of photovoltaic modules. Current and future innovation in formulations will lead to modules with longer useful lives and increased energy conversion efficiency. Development in process technology will lead to more durable panels that are less expensive to make. These advances will result in reduced cost per watt for the module maker and end module user.

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