What is photovoltaic film？

The photovoltaic film ‌ is a thin material used to package photovoltaic modules, primarily in the module-level packaging of solar panels. Photovoltaic film plays an important role in the solar photovoltaic technology industry, it plays the role of bonding cells and photovoltaic glass, and backplane is one of the key materials affecting the service life of photovoltaic modules and power generation. Photovoltaic encapsulation film is a core component of photovoltaic modules and its cost accounts for 3% to 4% of the cost of the module. There are many kinds of photovoltaic film, including transparent EVA film, white EVA film, POE film, EPE film, etc. Each film has its own specific advantages and application scenarios.

EVA solar photovoltaic film is a kind of internal packaging material widely used in photovoltaic modules. As a very important part of photovoltaic modules, EVA film can resist the external environment on the performance of the battery hard and damage, the battery plays a protective role.
The main component of EVA is the copolymer of ethylene and vinyl acetate, plus various additives such as crosslinking agents, thickeners, antioxidants, light stabilizers, and so on. EVA for photovoltaic packaging is mainly divided into four types: high transmittance, high cutoff, white and black. Among them, the single glass components usually adopt the package combination of high-transmittance EVA+ white EVA, which aims to increase the light reflectivity of the inner layer of the component while increasing the light transmittance of the front of the component and improving the photoelectric conversion efficiency of the component.
Black single glass components are usually packed with high-permeability EVA+ high-cutoff EVA+ black backplane or high-permeability EVA+ black EVA+ white backplane, where the role of high-cutoff EVA is to block the ultraviolet rays in the sun and reduce the damage of ultraviolet rays to the inner backplane.

POE film is a film made of POE resin as the main raw material by adding appropriate processing AIDS. Compared with EVA film, POE film is more secure, and its excellent water vapor barrier ability makes its water permeability only about one-eighth of the same thickness EVA film, which greatly improves the weather resistance of photovoltaic modules, especially suitable for water vapor sensitive battery package and photovoltaic modules working in humid environments. At the same time, due to the stable structure of the POE molecular chain, it will not decompose and produce acidic substances during the aging process, so it has excellent anti-aging properties. In addition, POE film has stronger anti-PID performance than EVA film, the use of POE film for packaging can effectively avoid the PID phenomenon, and improve the long-term reliability of photovoltaic modules, these excellent properties make POE film the preferred material for double-sided photovoltaic module packaging.

Although POE film is better than EVA film in PID resistance, aging resistance, water vapor barrier, and other properties, in terms of physical properties, POE is slippery, and the welding tape and battery are easy to move and run away during the lamination process, resulting in a reduction in the quality of component packaging.
In order to solve the above problems, we recommend the sandwich co-extruded structural film of EVA-POE-EVA, that is, EPE film. The upper and lower layers of EPE film are EVA film, and the middle is POE film. EPE film not only has the lamination process convenience and high adhesion of EVA material, but also has excellent anti-PID performance, low water vapor transmission rate, ultraviolet resistance, and moisture and heat resistance of POE material, which can solve the problem of welding tape and battery moving deviation during the lamination process, improve the package yield of components, and reduce the cost of film.