The solar PV Backsheet is a combination of different materials. It is a multilayer laminate formed by laminating two or more specialized polymer films together.
Backsheets from the outermost and ground-facing side of a solar PV module or Solar Panel.
As a whole, the Backsheet provides mechanical support to the module.
Among the layers of the Backsheet, the Inner or Cell side layer's primary function is adhesion with the encapsulant and blocking the UV rays coming from the front/cell side and the outermost layer protects the PV Cells from environmental stresses like dust, moisture, etc.
Two-side Fluoropolymer layered Backsheet:
This consists mainly of PVDF or PVF on either side of the PET (Polyethylene Terephthalate) based backsheet at the core.
Single-side Fluoropolymer layered Backsheet:
One way of reducing the cost of the backsheet while maintaining satisfactory behavior and durability is to reduce the number of fluoropolymer layers from two to one. In this case, the layered structure is formed mainly with PVF or PVDF on the airside and with PET or EVA layers on the inner side.
Non-Fluoropolymer layered Backsheet:
This consists of a specialized H-PET (Hydrolysed PET) on Air-side, with PET disposed on the central followed by EVA/Polyolefinic layer on the cell side.
HPET is a recent development to overcome the limitation of PET when disposed of on the airside. This was not considered earlier because of the possible degradation under UV exposure or hydrolysis over long periods. However, because of its cost-effectiveness and durability, it is able to support varying warranties and is often seen as an affordable option for fluoropolymers.
Data Credits : https://www.saurenergy.com/
Image Credits : RenewSys