How does a solar battery work？

Sunlight shines on the semiconductor p-n junction to form new hole-electron pairs. Under the action of the p-n junction electric field, the photo-generated holes flow from the n-region to the p-region, and the photo-generated electrons flow from the p-region to the n-region. current. This is how photoelectric effect solar cells work.

There are two ways of solar power generation, one is light-heat-electricity conversion, and the other is light-electricity direct conversion.

Folded Light-Heat-Electricity Conversion

(1) The light-heat-electricity conversion method uses the thermal energy generated by solar radiation to generate electricity. Generally, the solar collector converts the absorbed heat energy into working medium vapor, and then drives the steam turbine to generate electricity. The former process is a photo-thermal conversion process; the latter process is a thermal-electric conversion process, which is the same as ordinary thermal power generation. The disadvantage of solar thermal power generation is that the efficiency is very low and the cost is high. It is estimated that its investment is at least lower than that of ordinary thermal power generation. The power station is 5 to 10 times more expensive. A 1000MW solar thermal power station requires an investment of 2 billion to 2.5 billion US dollars, and the average investment of 1kW is 2000 to 2500 US dollars. Therefore, it can only be applied to special occasions on a small scale at present, and large-scale utilization is very economically uneconomical, and it cannot compete with ordinary thermal power plants or nuclear power plants.

Light-to-electricity direct conversion

(2) Light-to-electricity direct conversion method This method uses the photoelectric effect to directly convert solar radiation energy into electrical energy, and the basic device for light-to-electricity conversion is a solar cell. A solar cell is a device that converts sunlight energy directly into electrical energy due to the photovoltaic effect. It is a semiconductor photodiode. When the sun shines on the photodiode, the photodiode will convert the sun's light energy into electrical energy, generating current. When many batteries are connected in series or in parallel, it can become a solar cell square array with relatively large output power. Solar cells are a promising new power source with three advantages of permanence, cleanliness and flexibility. Solar cells have a long lifespan. As long as the sun exists, solar cells can be invested for a long time and used for a long time; In contrast, solar cells do not cause environmental pollution; solar cells can be large, medium and small, ranging from a medium-sized power station of one million kilowatts to a solar cell group for one household, which is unmatched by other power sources.