English
Photovoltaic power generation is a technology that uses the photovoltaic effect of the semiconductor interface to directly convert light energy into electricity, which is mainly composed of three parts: solar panels, controllers and inverters. The main components are electronic components. After the solar cells are connected in series, they can be packaged and protected to form a large area solar cell module, and then form a photovoltaic power generation device with a power controller and other components.
The main principle of photovoltaic power generation is the photoelectric effect of semiconductors. When a photon strikes a metal, its energy can be fully absorbed by the electrons in the metal. The energy absorbed by the electrons is large enough to overcome the Coulomb force inside the metal atoms to do work and escape from the metal surface to become photoelectrons. A silicon atom has four outer electrons. If pure silicon is doped with atoms with five outer electrons, such as phosphorus atoms, it becomes an N-type semiconductor. If pure silicon is doped with atoms with three outer electrons, such as boron atoms, P-type semiconductors are formed. When the P-type and N-type are combined, the contact surface forms a potential difference and becomes a solar cell. When the sun shines on the pn junction, the current flows from the P-type side to the N-type side, forming a current.
The photoelectric effect is an important and magical phenomenon in physics. Under the irradiation of electromagnetic waves above a certain frequency (this frequency is called the limit frequency), the electrons in some substances absorb energy and escape to form a current, that is, photoelectric. Polysilicon is made into silicon wafer after casting, breaking, slicing and other processes for processing. Doping and diffusion of trace boron, phosphorus, etc. A pn junction is formed on the silicon wafer. Then, through screen printing, the fine prepared silver paste is printed on the silicon wafer to make grid lines, and after sintering, the post electrode is made at the same time, and the surface with grid lines is coated with anti-reflection coating, so as to make a battery unit. The batteries are arranged and combined into a battery module to form a large circuit board. Typically the assembly is surrounded by an aluminum frame, with the front covered with glass and the back with electrodes. With battery components and other auxiliary equipment, a power generation system can be formed. In order to convert direct current into alternating current, it is necessary to install a converter. After generating electricity, it can be stored in a battery or fed into the public grid. In the cost of the power generation system, the battery component accounts for about 50%, and the current converter, installation costs, other auxiliary components and other costs account for another 50%.
Photovoltaic power generation advantages: Whether from the world or China, conventional energy is very limited. China's primary energy reserves are far below the world average, accounting for only about 10% of the world's total. Solar energy is an inexhaustible renewable energy for mankind, which has the advantages of clean enough, absolutely safe, relatively universal, long life and maintenance free, sufficient resources and potential economy, and plays an important role in the long-term energy strategy.
