The backsheet is a plastic-type covering you see on the back side of a solar module. This material forms an electrically intrinsic and weather-proof barrier preventing air and water ingress to the electrical components of the module. Typically made of a polymer type material (polyesters, polyamides or fluoride-based).
2DegreesKelvin have recently received an influx of backsheet investigation enquiries as chalking, powdering, cracks, delamination & water ingress is observed. Thorough site ‘touch-test’ surveys are required firstly to gauge the severity & scale of the issue. This needs to be followed up by a material validation exercise using specialist equipment, confirming the material on the modules throughout the site. From our initial findings we are seeing ‘Polyamide’ backsheets are significantly more susceptible to premature degradation than any other polymer blend, but provenance can’t be proven by manufacturers.
During the 2010-2015 period where module demand grew exponentially, polyamide materials where used as they were more readily available to manufacturers, so there are many sites out there that are effected.
How wide spread is this issue?
Is anyone seeing chalking out there?