What are ethylene vinyl acetate (EVA) films?
In the solar industry, the most common encapsulation is with cross-linkable ethylene vinyl acetate (EVA). With the help of a lamination machine, the cells are laminated between films of EVA in a vacuum, which is under compression. This procedure is conducted under temperatures of up to 150°C. One of the disadvantages of EVA films is that it is not UV-resistant and therefore protective front glass is required for the UV screening.

EVA film - solar cell encapsulation
For standard modules that use EVA encapsulation, for the backing usually a layer of tedlar composite (tedlar polyester tedlar (TPT)) is used, which is a thin, opaque film. Tedlar is the Dupont tradename for a film of polyvinyl fluoride, PVF, poly ethylene terephthalaye (PET) or metal.
Long term encapsulation and protection
Once the EVA sheets have been laminated, the ethylene vinyl acetate sheets play an important role in preventing humidity and dirt penetrating the solar panels. Also with the help of the EVA, the solar cells 'are floating' between the glass and backsheet, helping to soften shocks and vibrations and therefore protecting the solar cells and its circuits.  

   

EVA and TPT layer
 
Ethylene vinyl acetate (EVA) properties
Durability
Quality EVA film is known for its excellent durability, also in difficult weather circumstances, such as high temperature and high humidity.
Bonding
Under the right circumstances, EVA film will have excellent adhesive bonding to solar glass (NOT standard glass, solar glass has a rough surface). Also EVA bonds very well to the backsheet.
Optical
EVA is known for its excellent transparency. This means that the optical transmission is acceptable and doesn't block too much of the sunshine trying to reach the solar cells. Nowadays, several manufacturers in Asia use a transparent backing, which has transparency between the cells as a result. This type of module is known as semi-transparent.

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Factory Production Process

Q1: What is the guarantee of the machine?
A1: The guarantee period of our machine is 12 months after the machine is installed well in buyer's factory;
Q2: What package do you use for the machine?
A2: Painted the machine with anti-corrosion oil, and then covered with plastic film, and then packed into wooden case or fixed onto wooden pallet as per clients' requirements, or shall be loaded into container with film packing. After fixed all machines, we will use drying agent to keep container inside dry.
Q3: Do you have instruction manual to guide us if i buy the machine?
A3: Yes, we supply detailed user manual for your reference. PLS read it carefully for guide. If there is still problem which could not be solved, PLS contact us, we are ready to help you anytime.
Q4: What is your service to overseas clients?
A4: We supply perfect overseas service. We shall send engineers to overseas for machine installation and commissioning and test production guide, and also training to the workers of the buyer. And we are ready to give technical support anytime.