What is EVA Material？
EVA is one of the most critical encapsulation materials in the production process of solar modules. the selection and performance of EVA will not only affect the appearance and quality of solar modules but also affect the lifetime of solar modules.
The composition and properties of EVA
EVA is the main component of ethylene and vinyl acetate copolymer, plus a variety of additives such as cross-linking agents, thickeners, antioxidants, light stabilizers, and so on.
EVA has excellent flexibility, impact resistance, elasticity, optical transparency, low-temperature bending, adhesion, environmental stress cracking resistance, weather resistance, corrosion resistance, heat sealing, and electrical properties.
The role of EVA
EVA is flexible and has good bonding performance, with good light-transmitting properties and aging resistance of transparent colloids. EVA’s role is to solar cells “on the cover under the pad” seal in the middle, to protect the role of the cell.
At room temperature, EVA is solid, with no viscosity, and poor light transmission. When the EVA is heated to a certain temperature, EVA will melt and bond in contact with it the object. It has a high light transmission rate after melting, which can improve the incidence of light and increase the output power of solar modules.
In addition, in the solar module production process, lamination is the key link, and the parameters of the laminator are set around the characteristics of EVA. Therefore, EVA is critical to the production of solar modules.
The use of EVA in the process of precautions and consequences
1. EVA adhesive film has a strong adsorption capacity, in the use of the process, pay attention to moisture and dust, and avoid contact with colored objects.
- If moisture absorption, will affect the bonding strength of EVA and glass and back sheet, the water will be vaporized as the temperature rises, will produce bubbles.
- If dust absorption will affect the component light transmission, it will lead to EVA and the glass, the back of the bonding degradation, and even the bubble generation.
- If EVA and colorful, unclean objects are in contact, it is easy to be contaminated.
2. Do not expose the whole roll of EVA film to the air, and the film cut into pieces should be covered tightly if it cannot be used up on the same day.
- Do not touch the film directly with your hands. Oil or hand cream on hands will cause deterioration of EVA quality and poor bonding and discoloration.
- Avoid contact with water, oil, organic solvents, and pharmaceuticals. This can cause deterioration, poor bonding, and air bubbles.
- Can not be used in factories with open windows, garbage, and dusty places, which can cause EVA bonding to be low, and solar panels power shortage.
3. Storage environment for temperature below 30 degrees, and humidity below 60%.
Conclusion
EVA is an important part of solar modules. The long-term practice has proved: that it can obtain quite satisfactory results in both solar cell encapsulation and outdoor use.
Proper understanding and use of EVA, strict control of every aspect of the product, to produce high-quality products.
