Backsheet – a Guard for your Solar Modules

With the huge thrust on Renewable Energy Segment, a rapid growth of Global Solar PV market has been observed in the last five years. Lot of new demands were created – utility scale and roof-top segment have been phenomenal across the World. But often it has been observed that quality issues with the solar module come as an attached nightmare for the Industry. Rampant drive towards reduction of cost of solar power and ignorance about the solar modules’ materials aspects and its contribution towards life, have often lead to quality compromises which mostly lead to these problems.

One of the most critical constituent materials used in the construction of a Solar PV module is the backsheet. The backsheet is the outermost layer of the PV module placed at the non-sunny side of it. While the backsheet contributes only 4-5 % of the total cost of a solar panel, the criticality of a solar panel backsheet is quite high compared to its cost contribution. While choosing any solar panel, one needs to give enough thought in figuring out more about the backsheet. High quality backsheet will ensure solar panels’ longevity and ability to survive very difficult environmental conditions for 25 long years.

The backsheet is basically a polymeric laminate that protects the PV module from UV rays, moisture and other weathering aspects along with guarding as an electrical insulator. Thus it should have the superlative properties of protection against moisture ingress, weatherability, mechanical strength, adhesion, dielectric properties, reflectivity etc. or an optimized balance of all of these.

Generally, backsheet is a three-layer laminate but there are lot of varieties available in the market be it the basic protective layers like flouride-based polymers, polyesters, polyamides, polypropylene etc. or thickness or combination of layers. Till decade and half back, Tedlar was the only choice for protective layers of backsheets for solar modules – and it is still the only polymer that has proved its long-term (25 years or more) reliability in the field. The demand based economy had driven the backsheet industry to come up with newer technology based solutions in the form of PVDF which already has a proven track record of more than a decade. To serve the purpose of cost reduction, industry has seen the evolution of materials along with layers getting thinner and fewer, removal of solid innermost layer with PE based solution or usage of coatings. A wrong choice of backsheet can lead to severe adverse effect on modules and its very early failure due to backsheet’s cracking, yellowing and delamination etc.

SWELECT Energy Systems Limited has it’s presence in the Indian Electrical and Electronics market for more than 35 years and owns HHV Solar, which is one of the most reputed brands in Indian Solar PV market, mostly known for its quality of solar modules. The first and foremost ethical approach of this Company is to abide by the performance commitment of its solar modules for 25 years in reality so that the power producer’s investment economics should not get suffered after a few years. In ensuring the same, the Company has always insisted on using the best of the constituent materials chosen from across the Globe as it believes the quality of a module is as good as its choice of constituent materials. The BoM of SWELECT (HHV SOLAR) modules have always ensured the use of either Tedlar or PVDF based backsheet having superior specifications than the minimum requirement, be it the thickness of the core PET layer or overall thickness or the use of non-melting inner layer or specific technical parameters like WVTR, peel strength, better UV and sand abrasions resistance etc. Another important aspect is the choice of laminator i.e. the backsheet manufacturer. A lot depends on the art and expertise of making the backsheet. In order to ensure true 25 years’ life of the module, SWELECT never compromises on the choice of materials, even in today’s severe price sensitive Indian market scenario. SWELECT always uses the backsheets manufactured by the best of brands from across the world which has perfected the technology and have long presence in the market and well regarded in the Industry. These all ensures the true longer life during field exposure for 25 years in the harsh ambient condition.

The onus of choosing the backsheet in a module still lies with the customers but it’s prudent to remember that a poor quality backsheet can result in catastrophic failures which pose serious threats to installers and Operation & Maintenance of the plant, other than the economics attached to the whole equation of investment.

By Swelect Energy