Application of photovoltaic EVA hot melt adhesive film in module packaging

Application of photovoltaic EVA hot melt adhesive film in module packaging

Photovoltaic EVA hot-melt adhesive film is an indispensable key material in the packaging process of solar cell modules. It is laid between the cell sheet and the glass as well as the cell sheet and the backsheet, and plays various roles of bonding, sealing and protection during the lamination process.

The first is the bonding function. Under the high-temperature and high-pressure conditions of the laminator, the adhesive film is heated, melted and flows, which can fully wet the surfaces of glass, cells and backsheets. After cross-linking and solidification, a strong integrated structure is formed, tightly fitting each layer of materials, effectively avoiding defects such as delamination and bubbles in components during long-term use.

Second is the optical function. High-quality EVA film has a high visible light transmittance, allowing sunlight to reach the surface of the cell to the maximum extent. At the same time, its refractive index is between that of glass and silicon wafers, which can reduce interface reflection losses and ensure the photoelectric conversion efficiency of the module.

The third is the protection function. The adhesive film has good flexibility and cushioning properties, and can absorb vibration and impact during transportation, installation and use, preventing cracks or damage to the battery cells. At the same time, it can also block the penetration of water vapor and oxygen, prevent the cell electrodes and welding strips from being corroded, delay the yellowing of materials, inhibit potential-induced attenuation, and provide guarantee for the outdoor service life of the components for more than 25 years.

At the technological level, EVA film is generally melted at a lamination temperature of about 140 degrees Celsius, and then a cross-linking reaction occurs to form a stable structure. The degree of cross-linking is usually controlled within a reasonable range to ensure that the film has sufficient cohesive strength and maintains good adhesion. In addition, the adhesive film can also be used with functional materials such as UV absorbers and anti-PID additives to further improve the reliability of components in high temperature and high humidity environments.

In short, with its excellent adhesion, light transmittance, weather resistance and mature processing adaptability, EVA hot melt adhesive film plays a core role in module packaging and is an important factor in determining the quality, appearance and long-term power generation stability of photovoltaic modules.