The principle of photovoltaic power generation

The main principle of photovoltaic power generation is the photoelectric effect of semiconductors. When a photon is irradiated on a metal, its energy can be fully absorbed by an electron in the metal. The energy absorbed by the electron is large enough to overcome the Coulomb force inside the metal atom to do work, escape from the metal surface, and become a photoelectron. Silicon atoms have four outer electrons. If an atom with five outer electrons, such as phosphorus, is doped into pure silicon, it becomes an N-type semiconductor; If atoms with three outer electrons, such as boron atoms, are doped into pure silicon, a P-type semiconductor is formed. When P-type and N-type are combined together, the contact surface will form a potential difference, becoming a solar cell. When sunlight shines on the P-N junction, the current flows from the P-type side to the N-type side, forming an electric current.

The photoelectric effect is an important and magical phenomenon in physics. Under the irradiation of electromagnetic waves higher than a specific frequency (known as the threshold frequency), electrons inside certain substances absorb energy and escape to form a current, which is photogenerated electricity.

Polycrystalline silicon is processed into silicon wafers to be processed through processes such as ingot casting, ingot breaking, and slicing. Doping and diffusing trace amounts of boron, phosphorus, etc. on silicon wafers forms P-N junctions. Then, using screen printing, the finely prepared silver paste is printed on the silicon wafer to form a grid line, which is then sintered and made into a back electrode. A layer of anti reflective coating is applied on the surface with the grid line, and the battery cell is thus made. The arrangement and combination of battery cells form battery components, forming a large circuit board. Generally, aluminum frames are wrapped around the components, with glass covering the front and electrodes installed on the back. With battery components and other auxiliary equipment, a power generation system can be formed. In order to convert direct current into alternating current, a current converter needs to be installed. After power generation, it can be stored in batteries or input into the public power grid. In the cost of power generation systems, battery components account for approximately 50%, while current converters, installation fees, other auxiliary components, and other expenses account for the remaining 50%.