Principle of photovoltaic power generation
|Principle of photovoltaic cell|
The absorbed light can excite the bound electrons and generate "electron-hole" pairs. Under the action of electric field in the PN junction, the electrons and holes move with each other. If the battery is connected with a load at both ends, the current will flow through the load. As the light continues to shine, a steady stream of electric current flows through the load. A single solar cell is a wafer of semiconductor PN junction. Under standard lighting conditions, the rated output voltage is about 0.5v.
In the solar spectrum, different wavelengths of light have different energies and different Numbers of photons. As a result, the number of photons produced by a photovoltaic cell when exposed to light varies. The ratio of the photoelectric current collected by photovoltaic cells under the action of light energy at each wavelength in incident light and the number of photons at that wavelength relative to the incident light on the cell surface is called the spectral response of photovoltaic cells. The wavelength range of solar radiation capable of generating photogenic volt effect is generally 0.4~1.2um, and the maximum sensitivity is between 0.8~0.95um.