Backsheets: From Conception to Finished Products
TESTING AND CERTIFICATION
The films that are used for backsheets must offer protection against UV and moisture, durability, and the ability to provide electrical insulation. But the testing for these materials should go well beyond just these capabilities. Since solar panels and arrays can be installed almost anywhere in the world, strict testing protocols and adherence to a wide range of certification standards are crucial in an industry where non-compliance claims can irreparably damage the reputations and profitability of solar panel manufacturers. Certifications such as ISO and compliance with UL, IEC, and TUV quality standards usually mean that suppliers have established testing protocols to ensure the quality of their backsheet components.
Testing should consider the material’s direct support of live parts, its function as an outer barrier, enclosure protection and its role as a protective barrier. Some of the testing measures standards ranging from the comparative tracking index (measures the rates of resistance of an insulating material to electrical breakdown, which could cause a potentially hazardous conductive path on the surface) to high current arc ignition (determines the likelihood of a power surge by simulating a loose connection or broken lead). A partial discharge test can also verify that the backsheet is engineered with insulation properties to suit the voltage requirements of the module and UV resistance, thereby ensuring the appropriate resistance to UV degradation if the end use requires the backsheet be directly exposed to sunlight.
FINDING A SUPPLIER
Competent, trusted and well-established suppliers can provide the correct film constructions and adhesive combinations to make sure all aspects of solar module assembly meet end users’ requirements. With a fast-growing industry such as solar module construction and installation, it is best to be wary of the “supplier du jour,” who may not measure up to the standards required and the service and technical support that may be needed.
Solar manufacturers should look for a company that functions well beyond the confines of just sales and encompasses efficient, quality service and knowledgeable and dependable technical assistance. How long have they been in business? How would they find a solution to performance challenges, bonding or weather-related issues? Suppliers should have the ability to develop materials according to specifications and then test and deliver those products to optimize performance and minimize lost production hours and costs.
The availability of other related solar module products is another consideration when looking into a viable supplier. The concept of a one-stop shopping partner is a plus when the correct adhesives and other bonding, mounting and labeling materials and supplies are available, along with the technical expertise offered to make sure the correct components are being used.
Polymeric coated films can be ideal for many applications on a solar module. In addition to backsheets, high-performance adhesives in the form of transfer tapes and double-coated films can be used for cable, laminate and junction box fixation, along with cell placement. Durable film constructions provide brand identification and tracking label solutions.
The challenges faced by solar module designers and production staff are many and varied. It is important to find the right connections for all the elements that go into the finished product. Developing a relationship with a company that has a reliable, knowledgeable staff with quality, tested products is paramount in avoiding any unwanted production gaps or productivity lapses.
A proactive partnership should exist between all parties in helping to create viable product solutions to a variety of specifications, no matter how exacting. Working toward the development of next-generation products is an important factor in keeping any solar manufacturer’s products on the leading edge of the industry.
For additional information, contact FLEXcon at 1 FLEXcon Industrial Park, Spencer, MA 01562; phone (508) 885-8455; or visit www.flexcon.com/pv.
Note: Tedlar® is a registered trademark of E. I. DuPont Co. Kynar® is a registered trade name of Arkema.