The sun shines on the semiconductor p-n junction, forming a new hole-electron pair. Under the action of the p-n junction electric field, the hole flows from the n region to the p region, and the electron flows from the p region to the n region, and a current is formed after the circuit is turned on. This is how the photovoltaic effect solar cell works.
I. Photovoltaic power generation There are two ways of solar power generation, one is the light-heat-electric conversion method, and the other is the light-electric direct conversion method.
(1) Light-electric direct conversion method This method uses the photoelectric effect to directly convert solar radiation energy into electrical energy. The basic device for optical-electrical conversion is solar cells. A solar cell is a device that converts solar energy directly into electrical energy due to the photovoltaic effect. It is a semiconductor photodiode. When the sun shines on the photodiode, the photodiode turns the solar light into electrical energy. Current. When many batteries are connected in series or in parallel, they can become a square of solar cells with relatively large output power.
Solar cells are a promising new type of power source with three advantages of permanentness, cleanliness and flexibility. Solar cells have long life, and solar cells can be used for long-term use as long as the sun exists; and thermal power generation and nuclear power generation In contrast, solar cells do not cause environmental pollution.
(2)The light-heat-electric conversion method generates electricity by utilizing thermal energy generated by solar radiation, and generally the solar collector collects the absorbed heat energy into a working medium vapor, and then drives the steam turbine to generate electricity. The former process is the light-to-heat conversion process; the latter process is the thermo-electric conversion process, which is the same as ordinary thermal power generation.
The disadvantage of solar thermal power generation is that it is very inefficient and costly. It is estimated that its investment is at least higher than ordinary fire. The power station is 5~10 times more expensive.