Solar cells, also known as "solar chips" or "photovoltaic cells", are optoelectronic semiconductor sheets that use sunlight to directly generate electricity. As long as it is illuminated by light that meets certain lighting conditions, it can instantly produce voltage and generate current if there is a loop. In physics, it is called solar photovoltaic (photovoltaic, abbreviated PV), or photovoltaic for short. Solar cells are devices that directly convert light energy into electrical energy by photoelectric effect or photochemical effect. Thin-film solar cells that work with the photoelectric effect are the most widespread, while solar cells that work with the photochemical effect are still in their infancy. When light irradiates the pn junction, electron-hole pairs are generated. LCarriers generated near the P-N junction inside the semiconductor are not recombined and reach the space charge region. Attracted by the internal electric field, the electrons circulate in the n region and in the n region. holes Flows into the p region, resulting in excess electrons being stored in the n region and excess holes in the p region. They form a photogenerated electric field near the p-n junction opposite the direction of the potential barrier. In addition to partially compensating the effect of the barrier electric field, the photogenerated electric field also makes the p region positively charged and the N region negatively charged. An electromotive force is generated in the thin layer between the N region and the P region. is the photovoltaic effect.
When energy is added to pure silicon (for example, in the form of heat), several electrons break away from their covalent bonds and leave the atom. VSEvery time an electron leaves, a hole is left behind. These electrons then wander around the crystal lattice, looking for another hole to settle into. These electrons are called free carriers and can carry electric current. By mixing pure silicon and phosphorus atoms, it only takes a small amount of energy to escape some of the “extra” electrons from the phosphorus atoms (the five outermost electrons). When doped with phosphorus atoms, the resulting silicon is known as N-type (). the "n" means negative), only part of a solar cell is type N. Another part of the silicon is doped with boron. The outermost electron shell of boron contains only three electrons instead of four, which makes it possible to obtain P-type silicon.
Battery components
Composition components of solar cells and the functions of each part——
1) The vTempered glass is used to protect the main body of the power supply. generation (such as cells) and is transparent. There are requirements for its selection: 1. The light transmittance should be high (generally above 91%). 2. Ultra-white tempered treatment.
2) EVA is used to bond and fix tempered glass and the main body of power generation (such as battery cells). The quality of the transparent EVA material directly affects the lifespan of the component exposed to the EVA. the air is prone to aging and yellowing, which affects the light transmission of the module, thereby affecting the power generation quality of the module. In addition to the quality of the EVA itself, the module manufacturer's lamination process also has a big impact. For example, the bonding degree of EVA is not up to standard, and EVA is bonded to tempered glass and backplanes. Insufficient resistancewill cause premature aging of the EVA and affect the life of the components. It is mainly used to bond and encapsulate the power generation body and backplane.
3) The main function of cells is to produce electricity. The main market for power generation is crystalline silicon solar cells and thin-film solar cells, both of which have their own advantages and disadvantages. Crystalline silicon solar cells, relatively low equipment cost, photoelectric conversionThe conversion efficiency is also high, and it is more suitable to generate electricity under outdoor sunlight, but the consumption and cost of the battery are very high. Thin film solar cells have very low battery consumption and cost and have very good low light effect. They can also produce electricity underordinary lights, but they are relatively expensive and the photoelectric conversion efficiency is more than half that of crystalline silicon cells, such as solar cells in calculators.
4) Backplane function, sealing, insulation, waterproofing (usually TPT, TPE and other materials are used and must be resistant to aging. Most component manufacturers have a warranty 25 years old Tempered glass and aluminum alloy are generally no problem, the key lies in the ability of the backplate and silicone to meet the requirements)
5) Laminate. Aluminum alloy protector plays a certain sealing and supporting role.
6) The junction box protects the entire power generation system and functions as a power transfer station. If a component is shorted, the junction box automatically disconnects the chaine battery short-circuited to avoid burning the component. the entire system. The most critical thing in the junction box is that the selection of diodes depends on the type of cells in the module, and the corresponding diodes are also different.
7) Silicone sealing function is used to seal the junction between components and aluminum alloy frames, components and junction boxes. Some companies use double-sided tape and foam to replace silica gel. China and the process are simple, easy to use and inexpensive.
There are different types of materials for solar panels, some use crystalline silicon cells, others use amorphous silicon cells, etc. Solar cell (solar chip, photovoltaic cell) is an optoelectronic semiconductor sheet that uses sunlight to directly generate electricitytricity. As long as it is illuminated by light that meets certain lighting conditions, it can instantly produce voltage and generate current if there is a loop. In physics, it is called solar photovoltaic (photovoltaic, abbreviated PV), or photovoltaic for short.
Solar cells are devices that directly convert light energy into electrical energy by the photoelectric effect or photochemical effect. Crystalline silicon solar cells that work with the photoelectric effect are the most widespread, while thin-film cells that work with the photochemical effect are still in their infancy.