TPAT is the abbreviation of Tedlar- PET-AI Foil- Tedlar film which is a composite layer film that is a backsheet material in solar modules.
The backsheet consists of multiple layers of barrier films and adhesives. The construction of the backsheet is instrumental in protecting the solar cells from different environmental conditions like moisture, UV exposure and other performance threats while also improving solar module efficiency by aiding the reduction of partial discharge. To accomplish this, the solar panel material should be of a robust construction, typically a three layer laminate, and possess high dielectric properties. Most backsheets consist of combinations of films chosen for their different properties. Examples of standard films include: PET or EVA, Tedlar and Kynar. Combinations can be TPT (Tedlar/PET/Tedlar), KPK (Kynar/PET/Kynar) or PPE (PET/PET/EVA) among other combinations.
What is Tedlar?
Tedlar is the brand name of DuPont (American chemical company) and it refers to Polyvinyl fluoride (PVF), which is a thermoplastic fluoropolymer material that features high resistance to weather conditions and inherent strength, low permeability of moisture, vapor, oil and a wide temperature operation range (-70°C to +110°C).
Also Tedlar allows for a high degree of light spectrum permeability when transparent.
TPAT (Tedlar- PET-AI Foil- Tedlar) use in solar panels
The Tedlar- PET-AI Foil- Tedlar material combination provides a different performance range for Solar panel backsheets. Manufacturers used TPAT due to it’s protection from weather conditions and its high mechanical strength properties.
Tedlar- PET-AI Foil- Tedlar backsheet provides a range of properties as it has high mechanical strength compared to other common backsheet materials. The TPAT backsheet more importantly provides a hermatic seal, which guarantees protection for the solar cell against all weather conditions while providing electrical isolation from any metal frame. The decreased operating temperature is another benefit of the TPAT backsheet. Also the Tedlar Aluminum Tedlar Combination has low Water Vapor Transmission Rates (WVTR) which makes it withstand different exposure conditions like humidity in outdoor environments. Yet TPAT has a higher cost than some backsheet alternatives due to the high cost of Tedlar and manufacturing process.
Alternatives to TPAT (Tedlar- PET-AI Foil- Tedlar) backsheet
Tedlar is a comparably expensive material and cost is one of the main factors all manufacturers try to reduce by using alternative materials or even new panel types which require no Tedlar at all.
New backsheet made up of glass/ glass layer package designs are used primarily to decrease packaging costs. These new designs benefit from the simplification of the package and manufacturing process while they suffer from all the increased qualities provided by the TPAT backsheet material.