A solar panel is a complex piece of equipment that is constructed out of a variety of distinct components and different kinds of materials. A solar panel, also known as a solar photovoltaic module, is constructed out of solar cells, glass, EVA (ethylene vinyl acetate), a back sheet, and a frame.
These components make up the solar panel’s fundamental structure. The specific components depend on the kind of solar panel being used; the following are the three that are now on the market:
- Monocrystalline solar panels
- Polycrystalline solar panels
- Solar cells made of thin films
Although the first two of these are somewhat similar in many ways due to the fact that they are both types of crystalline solar panels, each of them involves a different set of materials as well as distinct manufacturing techniques. Silicon predominately serves as the primary component in the construction of solar panels of this type.
Crystalline silicon panels are also by far the most prevalent type of solar panel, accounting for around 95 percent of all commercially available solar panels at the present time. The production of mono-crystalline solar panels begins with a single crystal of silicon.
The production of polycrystalline solar panels begins with silicon ingots that contain many crystals of silicon each. The former type of silicon is a more pure form of silicon that is more efficient at converting solar energy into electricity. However, the cost of this type of silicon is more than that of the polycrystalline version.
EVA is used to hold the solar panels’ many individual components together as a whole. It is imperative that the EVA be of high quality in order to prevent the cells from being damaged and to assist the panels in withstanding adverse climatic conditions.
On the other hand, thin-film solar panels are manufactured from amorphous silicon, which makes them more flexible than even polycrystalline solar panels but results in a lower efficiency overall.
What exactly are photovoltaic cells?
Crystalline solar panels, which are made up of silicon crystalline cells, make up the great majority of solar panels despite the fact that other forms of solar panels do exist. The solar cells are the primary component that is responsible for converting the energy from the sun into electricity. A solar panel is comprised of dozens of solar cells working together.
Each solar cell is composed of a silicon wafer that has been coated with semiconductors. When light from the sun strikes semiconductors, it excites the electrons in those materials, which then results in the production of electricity.
This process, known as the photovoltaic effect, is the fundamental mechanism behind solar energy. This is also the reason why a solar cell is regarded as a photovoltaic (PV) cell in its more technical form. In order to convert a solar cell into something that can be used to power your household appliances, a number of extra components, such as wiring as well as protective frames and backing, are required.
To make it as effective as possible at soaking up the sun’s rays, an anti-reflective coating is also required to be applied to it. A solar panel is composed of a wide range of materials, including, but not limited to:
- Silicon (this is the main material that forms the base for the solar cells)
- Boron is added to silicon in order to give it a positive polarity.
- The front of the screen is covered with a thin layer of glass.
- backing made of polymer-based material
- Coating of phosphorous to impart a negative charge
- Coating designed to reduce glare, composed of silicon nitride or titanium oxide
- Frame made of plastic or polymer
How are photovoltaic panels manufactured?
Crystalline solar panels are produced in a manner that is, for the most part, consistent across all kinds, despite the fact that there are some subtle distinctions between monocrystalline and polycrystalline variations.
This is a step-by-step explanation that will walk you through the process of how crystalline silicon solar panels are manufactured. Crystalline silicon solar panels are the most prevalent type of solar panel. The following are the most important stages of the process:
1. Silicon is obtained from sand by various processes.
Crystalline solar panels are composed primarily of silicon, which is one of the elements that may be found in the greatest abundance on earth. The basic material for this type of production is sand, and silicon is removed from it. This process is similar to other types of manufacturing.
However, in comparison to the extraction of silicon used in a wide variety of other products, this method is more labor and skill intensive. Silicon of extremely high quality and purity is required for solar panels. This silicon is normally manufactured from quartz in an arc furnace at very high temperatures.
2. An ingot or “crystal” is formed by melting the silicon into a solid mass.
After being refined in the arc furnace, the silicon emerges in the shape of a rock-like substance. The next step in the process involves melting all of these rocks together to create an ingot in the shape of a cylinder.
This again necessitates the use of a furnace capable of reaching extremely high temperatures; however, this time the furnace must be made of steel and cylindrical in shape.
Boron is added at this point in the manufacturing process in order to provide the silicon with a positive electrical polarity. After melting, this helps to guarantee that all atoms are properly arranged in the structure they should be in.
When the silicon is heated in the furnace, an ingot of silicon is produced. This ingot can either be a single crystal of silicon, which is used for monocrystalline solar panels, or it can be a mixture of many crystals of silicon, which is used for polycrystalline solar panels. The merged crystals give the latter an identifying “shattered glass aspect,” which is a distinctive visual trait.
After being let to cool, the ingot is next ground down and polished so that all of its sides are flat.
3. The ingot is cut into discs using a saw.
After that, the ingot is cut using a precision wire saw into wafers, which are discs that are no thicker than a sheet of paper and have the same diameter. The silicon wafers have an anti-reflective coating applied to them in order to ensure that the maximum amount of sunlight is absorbed by the material rather than being reflected off of its dazzling surface.
4. Conductors made of metal are then added
When the silicon wafer has been processed and metal conductors have been put to the surface in the form of a grid-like matrix, the wafer is beginning to take on the characteristics of a solar panel. The sun’s rays are used to generate electricity via these conductors.
The wafer is placed in a chamber that is similar to an oven, and phosphorous is then diffused over the surface in the form of a thin coating. The phosphorus contributes a negative electrical charge, which complements the positive charge that the boron, which was introduced in step two of the process, already possessed.
The presence of both a positive and negative charge is necessary for the operation of a PV cell. When sunlight strikes a photovoltaic cell, it causes the electrons in the phosphorus and boron atoms to become excited. This causes the electrons to move around, which in turn creates a flow of electricity, which is then transferred through a wire to your battery or directly to the appliances in your home.
5. A solar panel is produced by assembling the cells into a larger unit.
At this point, we have a solar photovoltaic (PV) cell, but in order to construct a solar panel, the cells will need to be combined. When making a solar panel, a matrix-like structure consisting of several solar cells (typically between 48 and 72 cells) is created by soldering the solar cells to a base made of a conductive metal.
Standard solar panels typically have sixty cells, although residential panels of a lower size can have forty-eight cells, and panels used in industrial-scale solar installations typically have seventy-two cells each.
To complete the construction of the solar panel, a very thin layer of glass measuring 6-7 millimeters is adhered to the front, and then a back sheet composed of an extremely long-lasting polymer-based material is added. These aids to protect the solar cells and prevent dirt, water, or other impurities from entering the panel. They also help to safeguard the solar panel.
In order to further reinforce the panel, a protective frame and junction boxes have been put to it. These additions will allow for electrical connections to be made. The solar panel is shielded from damage caused by collision and the elements by the frame, which can also be utilized to mount the panel in the proper orientation.
The solar panels are put through one more round of testing before they are shipped out of the factory where they were manufactured to ensure that everything works as it should. The panel is typically placed in a flash tester, which subjects it to standard test circumstances, which include irradiance levels of 1000W/m2, cell temperatures of 77 degrees Fahrenheit, and an air mass of 1.5g. This is referred to as STC.
Each panel comes with a technical specification sheet that details the results of these tests as well as the panel’s ratings on a variety of parameters. Some of these factors include the panel’s power output, current, voltage, and efficiency, as well as its temperature and impact tolerance.
In addition, each solar panel goes through something called nominal operating cell temperature testing (NOCT), which is meant to simulate the circumstances that are seen in the actual world. In this test, the panel is subjected to irradiation of 800 W/m2, an ambient temperature of 68 degrees, and a wind speed of 1 m/s. The ratings obtained from this test are also given on the technical specification sheet for the panel.
After the solar panels have passed all of their tests, they are cleaned, examined, and then made ready for shipment!
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