Photovoltaic glass classification: Photovoltaic glass substrates for solar cells generally include ultra-thin glass, surface-coated glass, and low-iron content (ultra-white) glass. According to the nature of use and manufacturing method, photovoltaic glass can be divided into three kinds of products, namely the cover plate of flat solar cells, which is generally rolled glass; the surface of flat glass is coated with semiconductor materials with a thickness of only a few microns Conductive substrate for thin-film batteries; glass for lenses or mirrors used in collector photovoltaic systems. The characteristics and functions of these three products are completely different, and their added value is also very different.
The most widely used solar photovoltaic glass today is high transmittance glass, which is a glass with low iron content, which is commonly known as ultra-white glass. Iron is an impurity in ordinary glass (except heat-absorbing glass). The presence of iron impurities, on the one hand, makes the glass color, on the other hand, increases the heat absorption rate of the glass, which reduces the light transmittance of the glass.
The iron in the glass is introduced by the raw material itself, refractory materials or metal production equipment, etc., and it is impossible to completely avoid it. One can only reduce the content of iron in glass as much as possible through production control. At present, the iron content of solar cell glass is between 0.008% and 0.02%, while the iron content of ordinary float glass is above 0.7%. Low iron content impurities can bring high solar transmittance. For the most widely used 3.2mm thick and 4mm thick glass in China, the visible light transmittance of sunlight generally reaches 90%~92%.
As one of the most important components of solar energy devices, solar photovoltaic glass requires that the glass plate must be highly transparent. Therefore, the requirements for iron content in the siliceous raw materials used for the production of solar glass are very strict, and the content of Fe2O3 is generally 140-150ppm.
Application of photovoltaic glass. According to reports, the first country in the world to use transparent flat glass as a substrate to develop and apply solar cells is Germany. German scientists installed this plate-shaped solar cell as a window glass on buildings. It can directly supply the electrical energy absorbed by the households, and the excess electrical energy can also be fed into the power grid. The development and utilization of this initial glass for solar cells , which was soon valued by the United States and Japan and other countries, thus accelerating the pace of research, development and application of low-iron and ultra-thin glass for solar energy.