The Classification And Structure Composition Of Solar Panels

Solar panels are assembled from solar cells. According to the type of solar cell, it can be mainly divided into two types
1. Crystalline Solar Panel, which is assembled from polysilicon solar cells of monocrystalline solar cells.
2. Amorphous Solar Panel, which is assembled from thin-film solar cells or organic solar cells.

The feature of solar cells

(1) Monocrystalline silicon solar cells

The photoelectric conversion efficiency of monocrystalline silicon solar cells is about 15%-24%. This is the highest photoelectric conversion efficiency among all kinds of solar cells, but the production cost is so great that it cannot be widely used. As monocrystalline silicon is generally encapsulated with tempered glass and waterproof resin, it is rugged and durable, with a typical life up to 15-25 years.

(2) Polycrystalline silicon solar cells

The manufacturing process of polycrystalline silicon solar cells is similar to that of monocrystalline solar cells, but the photoelectric conversion efficiency of polycrystalline solar cells is reduced a lot, and its photoelectric conversion efficiency is about 12%. Because of its simple material manufacturing, saving power, making the total production cost low, so it has been greatly developed. In addition, the service life of polysilicon solar cells is also shorter than monocrystalline solar cells. In terms of performance, mono solar cells will be slightly better.

(3) Amorphous silicon solar cells
Amorphous silicon solar cell is a new type of thin-film solar cell that appeared in 1976. It is completely different from the monocrystalline silicon and polycrystalline silicon solar cell production methods, the process is greatly simplified, the silicon material is consumed less, the power consumption is lower, and its main advantage is that it can generate electricity in low light conditions. However, the main problem of amorphous silicon solar cells is the low photoelectric conversion efficiency. The international advanced level is about 10%, and it is not stable enough. With the extension of time, its conversion efficiency is attenuated.

Structure Composition

The structure of solar panel

(1)  Tempered Glass

Its role is to protect the main body of power generation (such as solar cells), the transmittance of tempered glass must be high, generally to reach more than 91%, and it need to be ultra-white tempered.

(2) EVA (ethylene vinyl acetate) Film

In the solar industry, the most common encapsulation is with cross-linkable ethylene vinyl acetate (EVA). With the help of a lamination machine, the cells are laminated between films of EVA in a vacuum, which is under compression.
The material of the transparent EVA directly affects the life of the components. EVA exposed to the air is susceptible to aging and yellowing, which affects the light transmittance and the power generation quality of the module. In addition to the quality of EVA itself, the laminating process of component manufacturers is also an important factor. For example, EVA adhesiveness is not up to standard, EVA and tempered glass, backsheet adhesive strength is not enough, it will all cause premature aging of EVA and affect the life of the components.

(3) Solar Cells

The mainstream solar cells in the market are crystalline silicon solar cells and thin-film solar cells. Both have their advantages and disadvantages. The production equipment of crystalline silicon solar cells costs are relatively low, the material consumption is so large that the cost of the solar cell is high, but its photoelectric conversion efficiency is also high. The production cost of thin-film solar cells is low, but its photoelectric conversion efficiency is not high. Its advantage is that it has a good power generation effect in weak light, and it can also generate electricity under ordinary lighting, such as solar cells on calculators.

(4) Back Sheet

The main function of the back sheet is sealing, insulation, and waterproofing. It generally used TPT, TPE and other materials which must be resistant to aging, most of the components manufacturers are 25 years warranty, tempered glass and aluminum alloy frame are generally no problem, the key is with the back sheet and silicone can meet the requirements.

(5) Aluminum Alloy Frame

Its role is to protect the laminate and play a certain role in sealing and supporting.

(6) Junction Box

The entire power generation system is protected and functions as a current transfer station. If a component is short-circuited, the junction box automatically disconnects the short-circuited solar cell string to prevent the entire system from being burned. The most critical part of the junction box is the selection of the diode. According to the type of solar cell in the module, the corresponding diode is not the same.

(7) Silica Gel

Sealing function, used to seal components and aluminum alloy frame, back sheet, junction box at the junction, the process is simple, convenient, easy to operate, and the cost is very low.