Introduction to solar panels & how they work

In this video, we're going to discover how solar panels work and how they are made. The main 3 parts of the sun are the convective zone, the radiative zone and the core. The core produces almost all of the sun’s heat through the nuclear fusion reaction of hydrogen into helium. This energy is carried by packets of light called photos all the way to earth.

In the late 1800s, scientists tried to capture this solar energy or photons with various elements like selenium, germanium, gallium, lithium and cadmium. In 1954, Bell Labs used silicon to create the first practical solar panel. Pure silicon is extracted from silicon dioxide or sand. This silicon is purified even further using a floating zone technique. This solid pure silicone ingot is sliced into thin wafers, 100-200 mm in width and 100-500 microns in thickness.

Why do we use silicon? First off, it’s a semiconductor. It doesn’t lose electrons as easily as a conductor and it isn’t as resistant to accepting electrons like an insulator. They are very versatile and act as a great base or starting point. Secondly, it’s resistivity falls as its temperature rises unlike metals. This means that when silicon is exposed to the sun and heated up, it allows electrons to flow more easily. Another reason is that silicon is the second most abundant material on earth. Most of the other semiconductor elements like germanium are scarce and hence more expensive.

Silicon has 4 valence electrons which are tied to other silicon atoms so it’s difficult to excite them. Other elements are added to silicon to provide the free electrons. Phosphorus, which has 5 valence electrons, is added to silicon in a process called negative or n type doping. Boron, which has 3 valence electrons, is added to silicon in a process called positive or p type doping. In the region where these n and p doped silicon meet, some free phosphorus electrons move to the boron atoms, and create a stable, depletion region with no free electrons.

Next let’s look at the 6 main components of a solar panel. The middle layer of solar cells are coated in an antireflective titanium dioxide coating helps prevent this loss of photons. Silicon is a shiny material which can reflect 35 percent of the sunlight without the coating. On either side of the panel, we have an EVA or Ethylene Vinyl Acetate Film. On the top side, we have a tempered glass sheet that protects the photovoltaic cells from the weather and impact from hail or debris. We also have a backsheet which acts as a moisture barrier. It is made of various polymers, usually polyvinyl fluoride or PVF. There’s a junction box on the back of the panel where all the cells interconnect. This entire system is wrapped in a light-weight, interlocking aluminium frame and sealed off with silicone to prevent any water or dust particles from damaging the cells.

The electricity generated by solar panels is one directional or DC or direct current. It can work for charging batteries or running a single lightbulb. But if you want to power many household appliances or sell this back to the grid, this DC current has to be converted to AC or alternating current with a solar inverter. This particular panel didn’t come with an inverter, but it does have a charge controller which is a very important part of a solar panel system. It regulates the flow of current to your expensive batteries and protects them from overcharging and undercharging. This charge controller ensures that the voltage at the battery does not exceed the 14 to 15 volt range while charging. It also drops the voltage to the 13.8 volt "float" charge level when charging is complete. The controller will also prevent the discharging of the battery when the solar panel is not in the sun.

So that’s an overview of a solar panel. I have a video on the black or monocrystalline and blue or polycrystalline panels coming out soon. If you have any questions about this video, leave me a comment below. Thanks for watching!
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SOURCES:
https://www.youtube.com/watch?v=jPijg8NIamo https://www.youtube.com/watch?v=LXxFgZcIihM https://www.youtube.com/watch?v=p66AWyzFIec
https://www.youtube.com/watch?v=xjatJ36cJvM
https://www.youtube.com/watch?v=WB8LrCWmGYw
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Видео Introduction to solar panels & how they work канала Belinda Carr