Backsheet repair coating

A backsheet repair coating is a coating, tape or foil put over a cracked module backsheet to bring its insulation resistance back. It is used for backsheet cracking. Cracks that go through the whole film mean the backsheet no longer meets insulation requirements, and insulation resistance collapses, especially in wet conditions, which is a serious safety risk. Dewy, torn backsheets can cause insulation faults that stop inverters from starting in the morning, which costs yield. With thermo-mechanical longitudinal cracks along the busbars, usually every module with the same backsheet type is affected. The whole system then has to be either repowered or repaired with a suitable coating or film. Repair does not work for squared cracks between cells, where acid from the encapsulant has chemically weakened the backsheet. In that case all modules of that bill of materials must be replaced. O&M service schedules list repairing backsheet cracks as an as-needed task, done by a journeyman electrician or a PV module or array specialist.

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• sentence 4: support check: partial - Passage says all modules with the same backsheet type are usually affected and the system must be repowered or modules repaired, but it says 'entire system must be repowered, or the modules repaired' (not the whole system repaired); also the longitudinal-crack link is fine, minor wording difference. -->