Classification of Solar Batteries: Solar Batteries
Solar Battery development is divided into three generations. The first generation is represented by monocrystalline silicon and polycrystalline silicon as silicon crystal solar batteries. The first generation of solar Battery technology with crystalline silicon as the material has been developed and most widely used. But the high raw material requirements of monocrystalline silicon solar batteries and the complex production process of polycrystalline silicon solar energy batteries and other shortcomings prompted people to start research and development of the second generation of thin film solar batteries, including cadmium telluride (CdTe), gallium arsenide (GaAs) and copper indium gallium selenide compounds (CIGS) as the representative of solar batteries began to become a research hot spot. Compared with crystalline silicon batteries, thin-film solar batteries require less material and are easier to produce on a large scale, so they show advantages in cost reduction and their efficiency is gradually improving. The third generation is based on high efficiency, green and advanced nanotechnology of new solar batteries, such as dye-sensitized solar batteries ( DSSCs ), calcium titanite solar batteries ( PSCs ), and quantum dot solar batteries ( QDSCs ), and so on. At present, all kinds of solar batteries have made great development, forming a solar Battery development pattern based on crystalline silicon solar batteries, thin film solar batteries as the development object, and DSSCs, PSCs, and QDSCs as the frontier.
1. The first type of solar batteries
1.1 Monocrystalline silicon solar batteries
Monocrystalline silicon is the most mature and stable type of solar Battery among all crystalline silicon solar batteries in terms of manufacturing process and technology. Theoretically, the best-forbidden bandwidth of photovoltaic response material is around 1.4 eV, and the forbidden band width of monocrystalline silicon is 1.12 eV, which is the closest single material to the best-forbidden bandwidth known to exist in nature. Monocrystalline silicon solar batteries are mainly prepared through wafer cleaning and fleece making, diffusion junction making, edge etching, dephosphorization of silicon glass, preparation of anti-reflection film, electrode making, sintering, and so on. After years of development, the manufacturing process and efficiency of monocrystalline silicon solar batteries have been greatly improved and enhanced. With its high efficiency and stability, monocrystalline silicon solar batteries dominate the PV industry and will remain so for a long time.
However, the purity of silicon material required for silicon batteries needs to reach 99.9999%, causing the price of monocrystalline silicon to remain high, in addition, the complex manufacturing process also makes it difficult to promote its use on a large scale. Therefore, in the subsequent development of monocrystalline silicon solar batteries, the main direction should be to simplify the production process and the required silicon material purification process in order to reduce the production cost of monocrystalline silicon solar batteries and speed up the popularization process.
1.2 Polycrystalline silicon solar Batteries
Compared with monocrystalline silicon solar batteries, polycrystalline silicon solar batteries require less purity of raw materials and a wider range of raw materials, so the cost is much lower than monocrystalline silicon solar batteries. Polycrystalline silicon solar batteries are also prepared by a wide range of methods, such as the Siemens method, silane method, fluidized bed method, sodium reduction method, directional solidification method, vacuum evaporation depending method, etc. Monocrystalline silicon processing techniques such as etching emission junction, metal absorption, etching flux, surface and body passivation, and refinement of metal gate electrodes are also available.
Compared with monocrystalline silicon solar batteries, polycrystalline silicon solar batteries have the advantage of low raw material requirements, especially since the manufacturing cost is lower. However, it also has its own disadvantages, such as more lattice defects resulting in lower conversion efficiency than monocrystalline silicon solar batteries. Therefore, for polysilicon solar batteries, research should focus on improving the polysilicon production process and reducing the defects in the polysilicon production process to enhance the original quality of the wafers. In addition, the manufacturing process of polysilicon solar batteries should be simplified to further reduce the production cost of polysilicon solar batteries in order to accelerate the development process of polysilicon solar batteries.