Principles Of Solar Panel Power Generation

Solar cells are devices that respond to light and convert light energy into electricity. There are many types of materials that can produce photovoltaic effects, such as monocrystalline silicon, polycrystalline silicon, amorphous silicon, gallium arsenide, selenium, indium, copper, and so on. The principle of their power generation is basically the same, and the process of photovoltaic power generation is described using crystalline silicon as an example. P-type crystalline silicon can be doped with phosphorus to obtain N-type silicon, forming a P-N junction.
When light strikes the surface of the solar cell, a portion of the photons are absorbed by the silicon material; The energy of photons is transferred to the silicon atom, causing electrons to undergo a transition, becoming free electrons that gather on both sides of the P-N junction and 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、 There are two ways of solar power generation: one is the light heat electricity conversion method, and the other is the light electricity direct conversion method.
(1) The light heat electricity conversion method utilizes the thermal energy generated by solar radiation to generate electricity. Generally, solar collectors convert the absorbed thermal energy into working medium steam, and then drive steam turbines to generate electricity. The former process is a light heat conversion process; The latter process is a heat electricity conversion process, similar to ordinary thermal power generation. Solar photovoltaic thermal power stations have high efficiency, but due to their initial industrialization stage, the investment is currently high. A 1000 MW solar thermal power plant requires an investment of $2 to $2.5 billion, with an average investment of $2000 to $2500 for 1 kW. Therefore, it is suitable for small-scale and special occasions, while large-scale utilization is economically uneconomical and cannot compete with ordinary thermal or nuclear power plants.
(2) Photoelectric direct conversion method This method uses the photoelectric effect to directly convert solar radiation energy into electrical energy. The basic device for photoelectric conversion is solar cells. A solar cell is a device that directly converts solar energy into electrical energy due to the photovoltaic effect. It is a semiconductor photodiode. When sunlight strikes the photodiode, the photodiode converts the solar energy into electrical energy, generating an electric current. When many batteries are connected in series or in parallel, they 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: permanency, cleanliness, and flexibility. Solar cells have a long lifespan, and as long as the sun exists, they can be invested once and used for a long time; Compared with thermal power generation and nuclear power generation, solar cells do not cause environmental pollution; Solar cells can be large, small, and medium-sized, ranging from medium-sized power stations with a capacity of one million kilowatts to solar cell packs that only serve one household, which are unmatched by other power sources.