The basic principle of photovoltaic power generation
Photovoltaic power generation is based on the "photovoltaic effect." When a photon strikes a metal surface, it can transfer its energy to an electron within the material. If the energy is sufficient, the electron can overcome the binding force of the metal and escape, becoming a photoelectron. This process is fundamental to how solar panels generate electricity from sunlight. When light shines on a semiconductor, it creates a potential difference between different regions or layers, such as between a semiconductor and a metal. This is the first step in converting light into electrical energy. The second part involves generating a voltage, similar to building a dam that holds back water. Once connected, this voltage allows current to flow through a circuit, creating usable electricity. The core principle of photovoltaic systems lies in the behavior of semiconductors. A silicon atom has four valence electrons. By introducing impurities like phosphorus (which has five electrons), the material becomes an N-type semiconductor, rich in free electrons. On the other hand, adding boron (with three electrons) creates a P-type semiconductor, which has more positive charge carriers, or "holes." When these two types are joined, they form a PN junction, which acts as the heart of a solar cell. When sunlight hits the PN junction, photons energize the electrons, causing them to move across the junction. Electrons move from the P-side to the N-side, while holes move in the opposite direction, creating a continuous flow of electric current. This is how solar cells convert sunlight directly into electricity. After the silicon ingot is cut into wafers, a small amount of boron or phosphorus is diffused into the surface to create the PN junction. Then, fine silver paste is screen-printed onto the wafer to form the grid lines, which help collect the generated current. After sintering, a back electrode is formed, and an anti-reflective coating is applied to the front to increase efficiency. These individual cells are then assembled into modules, often framed with aluminum, covered with glass on the front, and fitted with electrodes on the back. These solar modules are combined with other components, such as inverters, batteries, and mounting structures, to create a complete photovoltaic system. Inverters are used to convert the direct current (DC) produced by the panels into alternating current (AC), which can be used in homes or fed into the power grid. The energy can also be stored in batteries for later use. In terms of cost, solar panels themselves make up about half of the total system cost. The remaining expenses include inverters, installation, wiring, and other supporting equipment. As technology advances, the cost of solar power continues to decrease, making it an increasingly viable and sustainable energy solution. Heilongjiang Junhe Building Materials Technology Co., Ltd , https://www.junhejiancai.com