How solar panels work, what is the principle of power generation of solar panels

Photoelectric conversion effect, semiconductor interface includes: the interface of p-type region and n-type region formed due to different dopings, that is, p-n junction; interfaces where metals and semiconductors come into contact; Heterojunction interfaces made of different semiconductor materials and interfaces of MIS systems composed of metal insulator semiconductors. At each of these interfaces, there is a space charge region in which there is a strong electric field, called the self-built electric field.

The movement of electron-hole pairs generated by light under the action of a self-built electric field is the cause of the photogenerated voltaic effect. The following is a further explanation of the PN junction as an example. At the PN junction interface, there is a positive charge on one side of the n-region and a negative charge on the p-side of the p-region, and the direction of the self-built electric field in the space charge region is directed from the n-region to the p-region.

Since light can generate electron-hole pairs in the space charge region, they are swept by the self-built electric field to the n and p regions, respectively, just as an electron passes through the space charge region to the n region from the p-region, forming a photoelectric current. As long as they can reach the space charge region through diffusion motion, the electron-hole pairs generated in a certain range near the space charge region can also form a photoelectric current, and the distance that the electrons produced by the light and the hole diffusion motion can travel is the diffusion length. The photocurrent causes the accumulation of negative and positive charges in the n-region and the p-region, respectively, forming a potential difference on the p-n junction, causing a positive current in the n-junction in the opposite direction to the photoelectric current.

A stable condition is reached when the potential difference grows to the point where the forward current just cancels out the optical current, and the potential difference is called the open-circuit voltage. If the two ends of the PN junction are connected by an external circuit, there is a current flowing through, and when the load resistance of the external circuit is very low, this current is equal to the photoelectric current, which is called a short-circuit current.

Converts the energy of sunlight into electrical energy. Sunlight hits the panel, excites electrons in the semiconductor to an electrode, leaving holes at the excitation electrons to form a voltage.

A solar cell is a device that converts solar energy into electrical energy by using the photoelectric effect of semiconductor materials. The basic process of the photogenerated volt effect: assuming that light is shining on a solar cell and the light is accepted in the interfacial layer, photons with sufficient energy can excite electrons from covalent bonds in p-type silicon and n-type silicon, resulting in the generation of electron-hole pairs.

Before the electrons and holes adjacent to the interface layer are recombined, they will be separated by the electric field action of the space charge, and the electrons will move to the positively charged n-region and the holes will move to the negatively charged p-region.

The charge passing through the interface layer will form an outwardly testable voltage between the p-region and the n-region. In this case, electrodes can be added to both sides of the silicon wafer and a voltmeter can be connected. For crystalline silicon solar cells, the typical value of the open-circuit voltage is:

The more electron-hole pairs that are generated by light in the interfacial layer, the greater the current. The more light energy received by the interfacial layer, the larger the area of the interfacial layer, i.e., the cell, and the greater the current formed in the solar cell.

Advantages of solar panels:

1. Solar energy resources are inexhaustible.

2. Green and environmental protection. Photovoltaic power generation itself does not require fuel, has no carbon dioxide emissions, and does not pollute the air. No noise.

3. Wide range of applications. Solar power generation systems can be used wherever sunlight is available, regardless of geography, altitude and other factors.

4. There are no mechanical rotating parts, simple operation and maintenance, stable and reliable operation. As long as there is a solar energy in a photovoltaic system, the battery modules will generate electricity, and now they all use automatic control numbers, which basically do not need to be operated manually.

5. Abundant materials for solar cell production: Silicon materials are abundant, and the abundance of the earth's crust ranks second after oxygen, reaching as much as 26%.

The above content reference:

Anyone who has studied high school chemistry will know that the atom is composed of a nucleus and an electron, in which the electrons are constantly moving around the nucleus, which is also unstable, and as long as a small amount of energy can make the electrons deviate from the original electron motion track.

The principle of solar cells is to use the energy of sunlight to irradiate the atoms that make up the panel, so that the electrons in the atoms move directionally, so as to generate electric potential, that is, voltage, if there is a wire connecting high potential and low potential, it will produce current, which is commonly referred to as electrical energy.

Principle of solar cell power generation:

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 effects, such as: monocrystalline silicon, polycrystalline silicon, amorphous silicon, gallium arsenide, selenium, indium copper, etc.

The principle of their power generation is basically the same, and the process of light generation is described by crystal as an example. p-type crystalline silicon can be doped with phosphorus to obtain n-type silicon to form p-n junction.

When light hits the surface of a solar cell, a portion of the photons are absorbed by the silicon material; The energy of the photons is transferred to the silicon atoms, so that the electrons undergo a migration, becoming free electrons and accumulating on both sides of the p n junction to form a potential difference, when the external circuit is turned on, under the action of this voltage, there will be a current flowing through the external circuit to produce a certain output power. The essence of this process is the process of converting photon energy into electrical energy.

The manufacturing process of crystalline silicon solar cells:

Silicon "is one of the most abundant materials on our planet." Ever since scientists discovered the semiconductor properties of crystalline silicon in the 19th century, it has changed almost everything, even the human mind. At the end of the 20th century, we can see the figure and role of "silicon" everywhere in our lives, and crystalline silicon solar cells have formed the fastest industrialization in the past 15 years.

The production process can be roughly divided into five steps: a. purification process.

b. Pulling rod process.

c. Slicing process.

d. Battery making process.

e. Encapsulation process.

Applications of Solar Cells:

In the 60s of the last century, scientists have applied solar cells to space technology - communication satellite power supply, at the end of the last century, in the process of continuous self-reflection of human beings, photovoltaic power generation has become more and more intimate for such a clean and direct form of energy, not only in space applications, but also in many fields. Such as: solar garden lights, solar power household systems, independent systems for village power supply, photovoltaic water pumps (drinking water or irrigation), communication power supplies, cathodic protection of oil pipelines, power supplies for optical cable communication pumping stations, seawater desalination systems, road signs in towns, highway road signs, etc.

Advanced countries such as Europe and the United States have incorporated photovoltaic power generation into the urban power system and the power supply system of natural villages in remote areas into the development direction. The combination of solar cells and building systems has formed an industrialization trend.

Under the action of the built-in electric field of the p n junction, the photogenerated holes flow to the p region, and the photogenerated electrons flow to the n region, and the current is generated after the circuit is turned on. This is how photoelectric effect solar cells work.

The light-heat-electricity conversion method uses the heat energy generated by solar radiation to generate electricity, which is generally converted by a solar collector into the vapor of the working fluid, and then drives a steam turbine to generate electricity. The former process is the light-heat conversion process; The latter process is a heat-to-electricity conversion process, as is the case with ordinary thermal power generation.

The principle of photovoltaic cell power generation can be said to be the principle of photovoltaic power generation

Photovoltaic power generation is a technology that directly converts light energy into electrical energy by using the photogenerated volt effect at the semiconductor interface. The key element of this technology is the solar cell. Solar cells can be encapsulated and protected in series to form large-area solar cell modules, and then combined with power controllers and other components to form photovoltaic power generation devices.

The main specific principle of photovoltaic power generation is the photoelectric effect of semiconductors. When a photon irradiates a metal, its energy can be absorbed by an electron in the metal, and the energy absorbed by the electron is large enough to overcome the internal gravity of the metal to do work, escape from the metal surface, and become photoelectrons. A silicon atom has 4 outer electrons, and if an atom with 5 outer electrons such as a phosphorus atom is doped into pure silicon, it becomes an n-type semiconductor; If an atom with three outer electrons such as boron atoms is doped into pure silicon, a p-type semiconductor is formed.

When p-type and n-type are combined, a potential difference is formed at the contact surface, which becomes a solar cell. When sunlight hits the p n junction, the holes move from the p pole region to the n pole region, and the electrons move from the n pole region to the p pole region, forming an electric current.

The photoelectric effect described above is a phenomenon in which light causes a potential difference between an inhomogeneous semiconductor or between a semiconductor and a metal. It is first of all the process of converting photons (light waves) into electrons and light energy into electrical energy; Secondly, there is the process of forming a voltage.

Principle of solar battery power generation: 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 effects, such as:

Monocrystalline silicon, polycrystalline silicon, amorphous silicon, gallium arsenide, selenium, indium copper, etc. Their power generation principle is basically the same, and crystalline silicon has been used as an example to describe the process of light power generation. p-type crystalline silicon can be doped with phosphorus to obtain n-type silicon to form p-n junction.

When light hits the surface of a solar cell, a portion of the photons are absorbed by the silicon material. The energy of the photons is transferred to the silicon atoms, so that the electrons undergo a migration, becoming free electrons and accumulating on both sides of the p n junction to form a potential difference, when the external circuit is turned on, under the action of this voltage, there will be a current flowing through the external circuit to produce a certain output power. The essence of this process is the process of converting photon energy into electrical energy.

What are Semiconductors? What is the difference between n-type and p-type? Principle of solar cells (above).

The working principle of crystalline silicon N-type solar cells: when the p-type semiconductor and the n-type semiconductor are tightly combined together, a p-n junction is formed at the interface of the two. When the photocell is irradiated by sunlight, the accumulation of positive and negative charges is formed on both sides of the p n junction, which generates the photogenerated voltage and forms a built-in electric field, which is the "photogenerated voltaic effect".

Theoretically, if the electrodes are drawn from both sides of the built-in electric field and an appropriate load is connected, an electric current will be formed and power will be obtained on the load. Solar cell modules are solid-state devices that use the electronic properties of semiconductor materials to achieve Pv conversion.

Solar controller: The function of the solar controller is to control the working state of the whole system, and play the role of overcharge protection and overdischarge protection for the battery. In places with large temperature differences, qualified controllers should also have the function of temperature compensation.

Other additional functions such as light switches and time switches should be optional on the controller.

Battery: generally lead-acid battery, small and micro system, nickel-metal hydride battery, nickel-cadmium battery or lithium battery can also be used. Its function is to store the electrical energy emitted by the solar panels when there is sunlight and release it when needed.

Inverter: The direct output of solar energy is generally 12VDC, 24VDC, 48VDC. In order to supply power to 220VAC appliances, it is necessary to convert the DC power generated by the solar power generation system into alternating current, so a DC-AC inverter is required.

Efficiency is one of the important criteria when choosing an inverter. Higher efficiency means less power loss in the process of converting the direct current generated by the optoelectronic module into alternating current. It can be said that the quality of the inverter determines the efficiency of the power generation system, which is the core of the solar power system.

Simple: You understand that a solar panel is a photoelectric conversion device.

When sunlight is shining, there is a voltage and current output.

The larger the area, the greater the output power.

The academic type is as follows:

The photoelectric effect, also known as the photovoltaic effect.

The photogenerated voltaic effect refers to the phenomenon that an object generates an electromotive force due to the absorption of photons, and is an effect of electromotive force and current generated by the change of the charge distribution state in the object when the object is exposed to light.

When sunlight or other light irradiates the PN junction of a semiconductor, the photogenerated voltaic effect occurs. The photogenerated voltaic effect causes voltages to appear on both sides of the PN junction, which is called the photogenerated voltage. If the PN junction is short-circuited, an electric current will be generated.

When there is sunlight in the daytime, BT1 converts light energy into electrical energy, and DT2 is charged by D1, due to the light, the photoresistor is low resistance, and Q4 B is cut off at an extremely low mode barrier level.

When the matte rock is rotten at night, the resistor is high resistance, Q4 is on, Q2 B is also on at an extremely low level, and the DC denier jujube voltage circuit composed of Q3, Q5, C2, R6 and L1 works, and the LED is electrogized and emitted.

DC boost circuit.

Its core is a complementary tube ** circuit, its working process is: Q2 when the power supply is on L1, R6, Q4 to C2 charge, because the voltage at both ends of C2 can not be abruptly changed, Q3 B is extremely high, Q3 is not on, with the charging of C2 its voltage drop is getting higher and higher, Q3 B pole potential is getting lower and lower.

When the on-voltage is as low as Q3, Q3 is on, Q5 is turned on sequentially, and C2 is discharged through Q5 CE junction, power supply, Q3 EB junction (since Q2 is on, we assume that its EC junction is short-circuited, and Q3 E pole is directly positive of the power supply).