What role does EVA film play in the photovoltaic encapsulation process?

What role does EVA film play in the photovoltaic encapsulation process?

What is the role of EVA film in the encapsulation process of photovoltaic modules?

EVA film plays a vital role in the encapsulation process of photovoltaic modules. Its main function is to bond the photovoltaic glass, cells, and backsheet together, and at the same time play the role of protecting the cells and isolating the air. In modules, the cost of EVA film accounts for about 3%-4%.

The raw materials of EVA adhesive film include EVA resin, crosslinker, silane coupling agent and other modifiers. After these materials are stirred in a mixer, they are mixed in a closed container and let stand for a period of time, and then the mixture is extracted and placed in the adhesive film production line, and the cast is extruded into a molten adhesive film. The molten adhesive film is cooled by multiple cooling rollers, trimmed and harvested into rolls. When the module is laminated, it is heated to a certain temperature and the EVA is in a molten state, and bonding is realized.

The high fluidity of EVA adhesive film can ensure that it is tiled on the substrate, increase the contact area with the substrate, and rely on its own polarity and the performance of the substrate intermolecular force to form a physical bonding point and achieve bonding. Silane coupling agents are usually added to EVA adhesive film to improve their adhesion performance to photovoltaic glass and backsheets, because photovoltaic glass is an inorganic material with a smooth surface, and photovoltaic backsheets are fluorine-containing materials with difficult surfaces to bond.

In addition, EVA film becomes completely transparent after curing, has a fairly high light transmittance, can withstand atmospheric changes and is elastic, and encapsulates the solar cell wafer and adheres it to the upper glass and the lower TPT using vacuum lamination technology.

To sum up, the role of EVA adhesive film in the encapsulation process of photovoltaic modules is multifaceted, it is not only responsible for bonding the various parts of the module together, but also provides the necessary protection to ensure the long-term stable operation and efficient power generation of photovoltaic modules.