Coveme backsheet has a 5x lifetime extension

Product Briefing Outline: Coveme SpA’s new ‘dyMat PYE’ backsheet material is used to prevent electrical hazards and to grant high vapour barrier, thus avoiding power loss during the expected lifetime of the solar module. Coveme, in co-operation with DuPont Teijin Films, has developed a high grade PET inner layer with a lifetime five times longer than traditional polyester. Traditional solutions are multiple layer backsheets with fluoropolymers on the air side, polyester (PET) in the middle, and a third layer towards the cell side. Most of the job is done by the polyester film that must be protected by an outer layer versus the air side.

Problem: Due to water permeation of the outer layer, the inner PET layer suffers from hydrolysis losing its original properties.Therefore the traditional backsheets is, to a certain extent, unbalanced, having a long lasting outer layer and the inner layer suffering from early aging. This phenomenon cannot be detected with the naked eye but is only visible through deeper analysis. The problem analysis shows that improving the hydrolysis resistance of polyester is the key for a better performing backsheet. The outer layer on the airside consists in a white opaque film developed to resist the environment and further protect the inner PET layer.

Solution: The dyMat PYE laminate is based on two layers of polyester film. The cell side is treated with a special thick primer which provides high bonding capability to EVA. The primer can be supplied in different colours and in transparent finishing. The laminate thickness has been designed to provide the best combination of properties in terms of electrical insulation and weatherability. It also forms a strong barrier to oxygen and humidity.

Application: dyMat PYE is available in unlimited quantity and suitable for thin film and mono-/ polycrystalline solar modules.

Platform: dyMat PYE is certified by TUV to be resistant to Partial Discharge in the range 680 – 1220 VDC. It complies with Partial Discharge Test according to IEC 60664-1. Solar modules with dyMat backsheets are certified as per IEC 61215 and 61730. Master roll: 1.9 m x 3500 m. Customized reels: from 100 m length. Inner core: 3” or 6.” Cut sheets on request. Sizes and drills according to customer’s drawings. Different thickness and colour combination on request.

Availability: September 2008 onwards.