A kind of solar cell composite back film and preparation method thereof

Abstract

Disclosed is a composite back membrane for a solar cell, comprising a first back membrane (1), a second back membrane (2) and a third back membrane (3) successively. Adhesive layers (4) are also arranged between the first back membrane and the second back membrane and between the second back membrane and the third back membrane; and the first back membrane is adjacently connected to an ethylene-vinyl acetate copolymer adhesive membrane for a solar cell. The composite back membrane is characterized in that the first back membrane is a polytetrafluoroethylene membrane; the second back membrane is a composite membrane formed by compounding a polyethylene terephthalate membrane with fumed silica; and the third back membrane is a composite membrane composed of polycarbonate-zirconia-polytetrafluoroethylene. Also disclosed is a preparation method of the composite back membrane for a solar cell. The composite back membrane for a solar cell has a good mechanical property and a higher operating temperature; and the polarity of the surface of the composite membrane is also reduced; the adhesive force of dust is reduced; the dust deposition on the surface of the back membrane is reduced; and the service life of the back membrane is prolonged.

Description

technical field [0001] The invention relates to the technical field of solar cells, in particular to a solar cell composite back film and a preparation method thereof. Background technique [0002] Solar photovoltaic modules are mainly composed of glass cover, ethylene-vinyl acetate copolymer (EVA), cells, backplane, junction box and frame. Since the backsheet supports and protects the cells, and the backsheet is a packaging material that is in direct contact with the external natural environment on a large area, its performance directly determines the power generation efficiency and service life of the photovoltaic module. The backsheet must have excellent insulation , water vapor barrier and weather resistance, etc., so the impact of backsheet performance on solar photovoltaic modules is very important. The backplane plays a key role in battery life, output power, safety and reliability. Solar battery backsheets with poor performance will appear delamination, cracking, b...

AI Technical Summary

Problems solved by technology

[0004] Chinese patent 201110188877.4 discloses a solar battery back sheet, including a gas barrier layer, a process-resistant layer and several outer coating layers, and at least one outer coating layer is a composite film made of polyimide and Teflon, so The above composite film can be composed of polyimide film and Teflon film, or a co-extrusion film of polyimide and Teflon. The gas barrier layer can effectively block water vapor and is resistant to processing. The layer is suitable for laminating processing or providing a cushioning effect, polyimide resin has weather resistance properties, can protect the gas barrier layer, and Teflon can further block water vapor and anti-ultraviolet rays, but the solar cell prepared by the scheme of the prior art The backplane has poor heat dissipation and poor anti-fouling ability, which reduces the service life of solar cells to a certain extent

The solar backsheet prepared by this prior art has good tensile strength, high water vapor transmission rate, and high thermal shrinkage rate, but there are still problems such as poor heat dissipation and poor anti-fouling ability, which will affect the electrical performance of solar cells

[0006] In the prior art, part of the solar cell back film (back sheet) will turn yellow under the irradiation of ultraviolet light, resulting in the destruction of the molecular components of the back film layer, the overall performance of the back film is reduced, and the reflectivity of the back film is reduced at the same time. , which affects the overall output of the component

Moreover, if the heat transfer coefficient of the cell material is poor, the high local temperature will cause the material to vaporize, resulting in a bulge on the back film, and the bulge will gradually expand, causing the surrounding materials to oxidize and deteriorate, affecting the service life of the module

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