solar panel

A solar panel is a device that converts solar radiation directly or indirectly into electrical energy through the photoelectric effect or photochemical effect by absorbing sunlight. The main material of most solar panels is "silicon". It is so large that its widespread use still has certain limitations.

Compared with ordinary batteries and rechargeable batteries, solar cells are more energy-saving and environmentally friendly green products.

A solar cell is a device that responds to light and converts light energy into electricity. There are many kinds of materials that can produce photovoltaic effect, such as: monocrystalline silicon, polycrystalline silicon, amorphous silicon, gallium arsenide, indium copper selenide, etc. Their power generation principles are basically the same, and the photovoltaic power generation process is described by taking crystalline silicon as an example. P-type crystalline silicon can be doped with phosphorus to obtain N-type silicon to form a PN junction.

When the light hits the surface of the solar cell, a part of the photons is absorbed by the silicon material; the energy of the photons is transferred to the silicon atoms, causing the electrons to transition and become free electrons that accumulate on both sides of the PN junction to form a potential difference, when the external circuit is turned on , Under the action of this voltage, a current will flow through the external circuit to generate a certain output power. The essence of this process is: the process of converting photon energy into electrical energy.

1. Solar power generation There are two ways of solar power generation, one is the light-thermal-electric conversion method, and the other is the light-electric direct conversion method.

(1) The light-heat-electric conversion method generates electricity by utilizing the thermal energy generated by solar radiation. Generally, the solar collector converts the absorbed thermal energy into the steam of the working medium, and then drives the steam turbine to generate electricity. The former process is a light-thermal conversion process; the latter process is a thermal-electrical conversion process, which is the same as ordinary thermal power generation. Solar thermal power plants have high efficiency, but because their industrialization is in the initial stage, the current investment is relatively high. A 1000MW solar thermal power station needs to invest 2 billion to 2.5 billion US dollars, and the average investment of 1kW is 2000 to 2500 US dollars. Therefore, it is suitable for small-scale special occasions, while large-scale utilization is economically uneconomical and cannot compete with ordinary thermal power plants or nuclear power plants.

(2) Light-to-electricity direct conversion method This method uses the photoelectric effect to directly convert solar radiation energy into electrical energy. The basic device for light-to-electricity conversion is solar cells. A solar cell is a device that directly converts sunlight energy 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 and generate electricity. current. When many cells are connected in series or in parallel, it can become a solar cell array with relatively large output power. Solar cells are a promising new type of power source with three major advantages: permanence, cleanliness and flexibility. Solar cells have a long life. As long as the sun exists, solar cells can be used for a long time with one investment; and thermal power, nuclear power generation. 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 small solar battery pack for only one household, which is unmatched by other power sources.