A case study of double glass modules encapsulated with photovoltaic EVA hot melt adhesive film

The case of double-glass modules encapsulated with photovoltaic EVA hot-melt adhesive film can be referred to the actual application of a large ground power station. The double-glass module used in this project uses ultra-white rolled glass on the front and back, the battery cells adopt a double-sided power generation structure, and the packaging material uses high-transparency EVA hot-melt adhesive film. During packaging, the adhesive film is pre-cut into sheets that match the size of the module, and is laid on the upper and lower sides of the cell respectively, and then enters the lamination process. The lamination temperature is set at about 145 degrees Celsius. The vacuum stage lasts for about six minutes and the pressurization stage lasts for about nine minutes, so that the EVA can fully melt and flow and complete cross-linking and solidification. The cured adhesive film forms a tight integration with the glass and cells, the light transmittance remains above 91%, and the cross-linking degree is within the ideal range.

After the components are packaged, they undergo crack detection and appearance inspection. They also need to pass multiple reliability verifications such as moist heat aging, ultraviolet aging, and hot and cold cycles. The results showed that after being placed for one thousand hours under the harsh conditions of 85 degrees Celsius and 85% relative humidity, the module's power attenuation was controlled within 5%, no bubbles, delamination and other failures occurred, and the interface between the adhesive film and the glass always maintained good bonding strength.

This case shows that EVA hot-melt adhesive film can fully meet the bonding and protection requirements of double-glass components with its excellent optical properties, good melt fluidity and mature lamination process. At the same time, because the back side of the double-glass structure has the ability to block water vapor, the pressure on the hydrolysis resistance of the film is relatively reduced, making EVA widely used in this type of components. If the project is located in a high-temperature and high-humidity area or is sensitive to potential-induced attenuation, EVA can also be used in conjunction with other types of film to further improve long-term reliability. The overall solution takes into account both cost and performance, providing strong support for the large-scale promotion of double-glass modules.