Übersicht

In general, photovoltaic EVA film is referred to as photovoltaic film. As one of the components of solar modules, photovoltaic adhesive film is an essential component in the packaging of solar modules. Adhesive film is used to bind backsheets, solar glass, and solar cells. Its primary job is to safeguard the cells and encase them in DC power-producing photovoltaic modules. As one of the parts of solar modules, photovoltaic encapsulation film serves the following functions in the photovoltaic industrial chain: it encapsulates solar cells between photovoltaic glass and photovoltaic back materials, keeping air out and safeguarding the cells. It is the most expensive part of solar modules, making up between 3% and 4% of the total cost.

Encapsulation film, the fundamental component of solar modules, shields solar cells from the elements, increases the modules’ lifespan, and maximizes the amount of sunlight that reaches the cells through the film, increasing the modules’ capacity to generate electricity. The cells may be readily failed and discarded if the adhesive membrane of the battery module starts to turn yellow, break, or delaminate. Therefore, even though adhesive film and other membrane materials only make up around 5% of the overall cost of solar modules, they have a major impact on the longevity and quality of the final product.

Photovoltaic film types

There are several varieties of adhesive films, each with unique properties and uses. There are several different kinds of adhesive films available on the market right now, such as white and clear EVA, POE, and EPE adhesive films.

1. Transparent EVA film: used in the packing of solar modules, it has excellent adhesion to glass and backplanes, high light transmittance, resistance to UV yellowing, and resistance to snail markings. Water permeability and low reflectance are the drawbacks. High performance, simple to generate PID phenomena; extensively utilized in the upper layer packaging of single and double glass components;

2. White EVA-Folie is applied to the underside of solar module cells for encapsulation. It is highly reflective. The white EVA film may increase the power production efficiency of solar modules by reflecting sunlight back onto the cell surface. It can also suit the demands of single-glass, double-glass, and thin-film modules—all of which need high yield packaging processes and come at a relatively high cost.

EVA is a polar chemical that has high fluidity and stickiness. It is a hydrophilic polar group with an ester group in its structure and is readily hydrolyzed. The water vapor transfer rate is comparatively high due to the relatively loose cross-linked EVA molecular structure. The module’s water vapor transfer rate should be taken into consideration while employing EVA as the encapsulating layer. An extended service life of the module can be guaranteed by low water vapor transfer.

3. POE film: N-type and single-product PERC double-sided battery modules are made from POE resin as a raw material. It is particularly popular in the double-glass modules of the high-efficiency batteries mentioned above. Its anti-PID performance is stronger, its weather resistance is superior, and its water vapor barrier rate is greater.

4. Co-extruded POE film: Having a “EVA-POE-EVA” structure, it is an EPE film as well. It is a co-extruded POE film that combines the benefits of low-cost EVA with the anti-

PID performance of POE. It may be used to package solar modules with high requirements for weather resistance, such as PERC double-sided double glass, N-type double-sided double glass, and others. It features the double glass of EVA materials in addition to the high PID and water resistance of POE materials. The lamination technique has a high component output and is less vulnerable to the relative scarcity of POE resin availability as a raw material.
PID exhibits higher improvements in resistivity, water permeability, and hydrolysis resistance as compared to EVA. However, there are certain issues with the component process since its polar additives are more easily precipitated. Film industries have increasingly used co-extruded POE to assure component dependability while accounting for costs, in an effort to improve associated issues.

Benefits of solar-powered films

1. It is possible to apply high transparency and high adhesion to a variety of interfaces, such as those made of glass, metal, and polymers like PET.

2. Good durability is able to withstand extreme heat, moisture, UV radiation, and other factors.

3. Simple to pack away. Humidity and coatings that absorb water have no effect on the adhesion of EVA while it is stored at room temperature.

4. It has a greater sound-isolating impact than PVB, particularly for high-frequency sound effects.

5. Low melting point, flowable, and appropriate for a range of glass lamination techniques, including tempered, curved, and patterned glass.