Due to the difference in the pre-production process of monocrystalline silicon cells and polycrystalline silicon cells, they have some differences from appearance to electrical properties. From the appearance structure of silicon cell, the four corners of the monocrystalline silicon cell are arc-shaped and there is no pattern on the surface; the four corners of the polycrystalline silicon cell are square corners, and the surface has a pattern similar to ice flowers. The color of the anti-reflective film suede surface of the monocrystalline silicon cell is generally black and blue, and the color of the suede surface of the anti-reflective film of the polycrystalline silicon cell is generally blue.
For users, there is not much difference between monocrystalline silicon cells and polycrystalline silicon cells with the same conversion efficiency. The life and stability of monocrystalline silicon cells and polycrystalline silicon cells are very good. Although the average conversion efficiency of monocrystalline silicon cells is about 1% higher than that of polycrystalline silicon cells, because monocrystalline silicon solar cells can only be made into a quasi-square (four corners are arcs), there is Part of the area is not full. However, the polycrystalline silicon cell is square, and this problem does not exist, so the efficiency of the photovoltaic cell module is almost the same. In addition, due to the different manufacturing processes of the two battery materials, the energy consumed in the manufacturing process of polycrystalline silicon cells is about 30% less than that of monocrystalline silicon cells. Therefore, in the past few years, polycrystalline silicon batteries accounted for an increasing share of the total global battery production, and the manufacturing cost is much lower than that of monocrystalline silicon batteries. From the perspective of production technology, the use of polycrystalline silicon batteries is more energy-efficient and environmentally friendly.
With the continuous development of polysilicon cell manufacturing technology, the conversion efficiency of polysilicon cells has increased from the current 17% to 17.5% to more than 18%, and it has become a high-efficiency cell. Compared with the traditional polycrystalline cell, the high-efficiency polycrystalline cell has no other difference in appearance except that the surface color has changed to black. But in fact, the efficiency of this kind of cell is 0.3%~0.7% higher than that of the traditional cell. However, it is very difficult to increase the efficiency by 0.1% with the original polysilicon cell production technology. The technical principle of high-efficiency polycrystalline solar cells is to chemically etch the large-sized pits on the surface of the original battery into many small pits. That is, nano-sized pores are generated in the nano-structure of the original battery, which reduces the reflectivity of the battery surface from the original 15% to about 5%. As the utilization rate of sunlight increases, the efficiency of the battery will naturally increase. The cell material obtained by the chemical reaction is black in appearance, hence the name “black silicon”, and this technology is also called black silicon technology.
Nevertheless, judging from the current manufacturing technology, the conversion efficiency of polycrystalline silicon cells is close to the laboratory level, it is difficult to reach 18.5% or more, and the room for improvement is limited. With the continuous improvement of monocrystalline silicon cell manufacturing technology, the conversion efficiency of P-type and N-type monocrystalline silicon cells has reached 19%~19.5% and 21%~24% respectively. The improvement of conversion efficiency has gradually reduced the manufacturing cost of monocrystalline silicon cells, which has been basically the same as that of polycrystalline silicon cells. The advantages of monocrystalline silicon cells in photovoltaic power generation systems (power stations) in terms of power generation, power generation costs, and power generation yield will gradually emerge. According to calculations, in accordance with the 25-year service life generally promised by the industry, a photovoltaic power station of the same scale, using monocrystalline silicon cell modules, will generate 13.4% more power generation revenue than using polycrystalline silicon cell modules. Although the current cost per watt of monocrystalline silicon cell modules is about 5% higher than that of polycrystalline silicon cell modules. However, due to the high power generation efficiency of monocrystalline silicon modules, the same installed capacity covers a small area, and the use of peripheral equipment such as foundations, brackets, cables and other systems is also correspondingly reduced. The comprehensive input costs of the two are basically the same.