Photovoltaic manufacturing is undergoing change in terms of technology and materials. Production costs per module need to come down to a more profitable level whilst maintaining durability and enhancing performance and functionality. AMI is organising the 2nd international conference on Polymers in Photovoltaics 2011 in Cologne to discuss these issues. Senior Consultant, Kerry Satterthwaite will outline the market situation and future prospects, and lead manufacturer Solarfun will talk about the latest developments in modules.
A wide range of polymer materials is in use in solar modules in functions such as backsheets, silicon encapsulants, sealants and adhesives, and innovative front sheets. Multilayer, multi-material structures are now common for backing sheets with different functions provided by each layer. Industry standards are being developed by bodies such as Underwriters Laboratories and TUV with flammability and weathering performance testing. Polymers offer flexibility in production and use, however they must be properly specified and selected and there must be good inter-material adhesion and compatibility under the high performance conditions of moisture, sunlight, wind and snow in different areas of the world.
Renolit Belgium has entered the market with innovative backsheets including an integrated encapsulant layer for crystalline silicon PV modules. PET is increasingly being used in backsheets, so much so that a shortage is being predicted in the marketplace. Toray Films Europe supplies advanced PET films for photovoltaics. Saint-Gobain Performance Plastics supplies a range of materials for solar applications and is looking at lightweighting options with plastics components. On the manufacturing side, Davis-Standard supplies extrusion expertise and equipment for encapsulant and backsheets.
Increasingly, polymers are being used as front sheets, for example the fluoropolymers PVDF and ECTFE from Solvay-Solexis, which also find use in backsheets. Another plastic for front sheets is PMMA, from companies such as Evonik Rohm, which is being tested in PV, BIPV and CPV.
Sealants and adhesives are critical for module performance. The US National Renewable Energy Laboratory is involved in most aspects of module and materials testing for the photovoltaic industry, and Dr Michael Kempe has recently completed a study on testing of edge-seal materials. Saes Getters of Italy supplies a novel edge sealing “getter tape”, and 3M Deutschland is a leader in these applications.
The Fraunhofer Center for Silicon Photovoltaics has studied many aspects of polymer materials, and has reviewed the processing and mechanical behaviour of the encapsulants used for embedding solar cells. ECN is another lead research institute in photovoltaics and has looked at the balance between encapsulation quality and robustness. A small range of polymers are used in encapsulation, Specialized Technology Resources, Inc. is looking at next-generation materials. Huntsman Advanced Materials is one of the companies developing new materials and concepts for high efficiency modules. UV curing technology is being tested for encapsulants by Sartomer USA. Module manufacturing equipment is supplied by Meyer Burger Technology (Switzerland), and the company has looked at the use of EVA compared to other encapsulants for crystalline PV. In France, the Institut National de l’Energie Solaire is coordinating the European IMPRESS project, which is looking at injection moulding of encapsulants and PV frames.
AMI’s Polymers in Photovoltaics 2011 Conference brings together top materials experts, module component and module manufacturers to discuss the best materials and manufacturing technologies for the solar industry. It offers a meeting point for the industry to debate business trends and improvements in materials and properties. It provides a unique opportunity to network with the wide range of professionals who work with and produce photovoltaic systems worldwide.