EVA (ethylene-vinyl acetate copolymer)

Adhesion:
EVA has a strong adhesion ability and can firmly bond the solar cell, glass panel and back panel together to form a stable whole. This adhesion is crucial in the manufacture and use of solar panels. It ensures the close combination of various components and prevents problems such as delamination and falling off.

Good adhesion can also improve the mechanical strength of solar panels, enabling them to withstand certain external force impact and vibration.

Light transmittance:
In order to ensure that solar cells can fully absorb sunlight, the packaging material needs to have good light transmittance. EVA has a high light transmittance, which allows most of the sunlight to pass through and reach the surface of the solar cell, thereby improving the photoelectric conversion efficiency of the solar panel.

The light transmittance of EVA can also reduce the reflection and scattering of light, allowing solar cells to use sunlight more effectively.

Weather resistance:
Solar panels are usually installed outdoors and exposed to various natural environments for a long time, such as sunlight, rain, wind and sand, high temperature, low temperature, etc. Therefore, the packaging material needs to have good weather resistance, be able to resist the influence of these environmental factors, and maintain its stable performance.
EVA has good resistance to UV rays, aging, humidity and heat, and can be used outdoors for a long time without obvious performance degradation. It can effectively protect solar cells from erosion by water vapor, dust, etc., and extend the service life of solar panels.
2. Backplane
Selection of polymer materials:
Polyvinyl fluoride composite film (TPT) and polyethylene terephthalate (PET) are commonly used backplane materials. These polymer materials have good insulation, waterproofness and aging resistance, and can provide reliable protection for solar cells.
TPT usually consists of three layers of materials, the middle layer is polyvinyl fluoride (PVF), which has excellent weather resistance and corrosion resistance; the upper and lower layers are polyester film (PET), which provides mechanical strength and insulation. The PET backplane is made of a single polyester film, which has the advantages of low cost and good processing performance.
Insulation:
The insulation performance of the backplane is crucial to the safe operation of solar panels. It can prevent solar cells from contacting external conductive objects and avoid safety accidents such as leakage and short circuit.
Polymer materials usually have good insulation properties, which can effectively isolate solar cells from the external environment and ensure the safety and reliability of solar panels.
Waterproofness:
Solar panels need to be used outdoors for a long time, so the backplane needs to have good waterproof properties to prevent water vapor from penetrating into the interior of the solar cell and affecting its performance and life.
Polymer materials such as TPT and PET have low water vapor permeability, which can effectively prevent water vapor from penetrating. At the same time, the edges of the backplane are usually sealed with sealants to further improve the waterproof performance of solar panels.
Aging resistance:
The backplane needs to have good aging resistance and be able to maintain its performance stability during long-term outdoor use. Aging resistance includes resistance to ultraviolet rays, resistance to humidity and heat, and resistance to high and low temperatures.
Polymer materials can be specially treated and formulated to improve their aging resistance. For example, adding additives such as ultraviolet absorbers and antioxidants can effectively resist the effects of ultraviolet rays and oxidation; using special coating technology can improve the resistance to humidity and heat of the backplane.