Who Affects the Life of The Backplane of New Energy Photovoltaic Modules?

In photovoltaic modules, the photovoltaic back sheet is a protective material, which mainly plays the role of supporting components, isolating water vapor and oxygen, and has to withstand the test of very complex and different outdoor environments around the world, so the reliability of its materials is crucially important. Its structure is shown in the figure: from the outside to the inside from the air surface:

1) Fluorine film protective layer.

2) Adhesive layer 1.

3) Support layer PET film.

4) Adhesive layer 2.

5) Inner protective layer.

(1) Fluorine film protective layer on the air surface; the main function is to protect the PET support layer from ultraviolet and sand erosion, and to weaken the PET degradation speed, so as to ensure the efficient operation of the crystalline silicon module, the "heart" of the photovoltaic module.

(2) Adhesive layer 1 and adhesive layer 2. The main purpose is to bond the fluorine film layer and the PET layer together, without weakening the bonding effect due to the action of water vapor, high temperature, etc., and eventually lead to the separation of the fluorine film layer and the PET layer and lose the due protective effect of the fluorine film layer.

(3) PET support layer. It mainly plays the role of mechanical support and isolation of water vapor and oxygen; it does not lose its proper support and protection due to accelerated degradation or cracking under the action of water vapor, oxygen and high and low temperature.

(4) The inner fluorine film protective layer. Because the inner layer is not in direct contact with the outdoor atmospheric environment, only the irradiation of the frontal sunlight, the use requirements of the inner layer are not as strict as those of the air surface protective film.

From the perspective of the structure of photovoltaic modules, if the crystalline silicon wafer is compared to the "heart" of the module, then the photovoltaic backsheet can be compared to the "armor" of the module, and the fluorine film protective layer on the air surface can be compared to the "bulletproof" Clothes". The existence of "body armor" can significantly extend the service life of "armor" and indirectly prolong the service life of the entire component. Therefore, the quality and reliability of the fluorine film protective layer is very important.

Thickness is directly related to film product performance and has a significant impact on aging performance. When choosing a thinner fluorine film protective layer, the product structure design should be done according to the environmental complexity of different regions, and a fluorine film with a reliable thickness should be selected as the protective layer.

In complex and different environments, the protective film for the back sheet of photovoltaic modules will have a thinning trend under the combined effect. From the perspective of thinning speed and various performances, it is recommended to ensure the thickness of the PVDF film for the back sheet of photovoltaic modules in harsh environments. When it is above 25um or even 30um, it can more securely ensure the long-term operation of photovoltaic modules.