Generate Electricity - How Solar Panels Work!

Why are there crystals here but not on this one and how do

solar

panels

work

? Let's find out you can now buy a mug and hoodie to help support the channel links below. Solar

panels

convert light into

electricity

. They are photovoltaic, that is, light and voltage. It

work

s with sunlight or artificial light, take a small

solar

cell, set up your multimeter, connect the wires and expose it to some light, instantly we see that a voltage is

generate

d, the stronger the light, the more

electricity

is produced, but Can this be reversed if we connect the solar cell to a power source it produces infrared light which the human eye cannot see, but if we take a camera and remove the filter we can see that the light is produced from the cell.

Light is basically a bunch of particles called photons. The cell absorbs these photons when they hit the solar cell, they knock another particle called an electron out of the solar cell leaving a hole behind. This is the photovoltaic effect. I'll explain in detail how it works later in the video, but the hole moves down. towards the bottom and the electron is attracted to the top layer, the electron is attracted towards the hole similar to how opposite ends of a magnet are attracted. If we provide a path using a wire, the electron will flow through it to return to the hole we placed. things like LEDs in the way and that way the electron has to flow through them causing it to emit light which means it emits photons, so if the LED emits photons and the solar cell absorbs photons, can the LED yourself tell me your answers? in the comments section and I'll tell you the answer later in the video, you've probably seen solar cells on your calculator or in your garden lights.

They are often used on RVs and boats, we see them on houses and even on large solar panels in fields. an array is just multiple strings of solar modules connected together a string is just multiple solar modules connected together and the solar module is just multiple solar cells connected together to make a basic solar cell we start with a metal conductive plate that forms the positive electrode on top of this we find a thin layer of silicon, this is our semiconductor material. It usually consists of a silicon boron mix layer on the bottom and a silicon phosphorus layer on top.

The junction between them is known as a PN junction on top of the silicon. We have an anti-reflective coating. A metal grid is then placed over this, which is our negative electrode. The thin strips are known as fingers and the thicker strip is known as a bus bar. We normally have a protective layer of glass over this because the solar cells. They are very thin and will break easily, so we must protect them. This small cell has the bus bar on the edge, this one goes through the middle and these big ones have multiple bus bars in the middle.

They all have fingers that extend through the silicon. To collect the free electrons, these electrons will flow along the fingers and then collect and flow together on the bus bars. We need as much light as possible to enter the silicon, so metal conductors need to be as thin as possible. More fingers do it. It is easier to collect more electrons but it also blocks light. The silicon material is shiny which means light is reflected, so the anti-reflective coating helps reduce this, but some will always be reflected. We also find cells with this rough surface that helps capture part of the electrons.

It reflects light and directs it back to the solar cell. Each of these cells

generate

s only 0.5 volts, but the larger the cell, the more current it can generate to make a solar module. We have a solid backsheet with a layer of Eva adhesive on top and then the solar cells are glued to this and connected to each other, another layer of Eva film is placed on top, then a layer of glass and finally the frame is placed on the back. later. We have the electrical connections that connect to the cells. Eva encapsulates the solar cells, insulating them.

Protect them from humidity and mechanical stress that would degrade the material over time. Looking at solar modules, the top of one cell is connected to the bottom of the next cell and this increases the voltage. Looking inside this unit, we have two cells, both producing 0.5. Vols if we look closely we can see the cells overlap and join together to form a serious connection, the ends pass through the back where we find the electrical terminals. The small modules use 36 cells producing around 18 to 19.8 Vols, perfect for charging a 12vt battery because it needs more voltage than the battery to charge it, so we often find them used for off-grid systems, but most residential installations are grid connected and use 60 or 72 cell modules.

Commercial installations generally use 60 modules of 72 or 96 cells, some can be even larger when we connect cells in series, the voltage adds but the current remains the same. This module uses 60 cells, each of which provides about 0.5 volts and 8 amps of current, so it produces about 30 volts and 8 amps, giving us 240 W of power if we connect four of these modules. In series we would obtain 120 volts and 8 amps, the voltage is added but the current remains the same, this gives us 960 watts, but if we connect four in parallel we obtain 30 volts and 32 amps, the voltage is the same, but the current is Added up, this also gives us 960 watts.

We often use a combination of parallel series connections. The modules connect to a charge controller and an inverter. These have a maximum and minimum voltage and current to operate, for example this could be 100 to 150 volts. and 25 amps our string of modules is 120 volts and 8 amps so we can't add another string in series because we will exceed the voltage limit so we connect two strings in parallel giving us 120 volts with 16 amps the system could be independent. or connected to the grid, we can use a solar panel to directly power a load, but it only works when exposed to light, for example, this solar fan will turn on automatically when exposed to light, the brighter the light, faster it will spin, but it doesn't work at Therefore, at night we need a battery to store the energy that charges during the day and then we can use it at night.

This is how this very simple battery charger works. However, the voltage and current will vary and the solar module may overcharge the battery, which will damage it. and at night the battery can be discharged again through the solar panel, so we separate them using a charge controller. Now when the sun shines the controller charges the battery, we can turn on the light and the controller sends power to the load with any excess power. If we are going to charge the battery overnight, the controller protects the battery's solar panel but still allows us to use the energy stored in the battery and that is how these solar powered phone chargers work.

You can see in this simple garden light that inside it has just a solar cell connected to a basic charge controller, this separates the battery and the LED, the solar cell charges the battery and when charging stops the light turns on . We can also control the light with the switch, the solar panel and battery provide DC electricity. If we connect this multimeter to a battery, we see a constant flat voltage which is due to electrons flowing in one direction, much like the flow of water in a river. We can use it to power small DC motors, lights and USB devices, perfect for RVs and boats, but many of our appliances require AC electricity, which works differently if I connect to this power circuit, we have a wave pattern , the electrons flow back and forth, the direction alternates, much like the sea tide that comes in and out to power these devices.

We need an inverter that converts DC to AC inside. Basically, we just have some electronic switches that turn on and off extremely quickly to control the path of the electrons. You can watch our detailed inverter video for more information, but using an inverter allows us to use both AC and DC devices from this system; However, the battery will run out of power if not recharged for domestic and commercial installations, therefore we often connect to the grid in a simple system, just have the solar panels connected to an inverter. This powers the circuit breaker panel and AC loads on the property, the mains is connected via meter to the panel and therefore the inverter must synchronize with the grid at night, no solar power is generated so that we buy electricity from the grid on a sunny day.

The solar panels will be enough to power some elements inside the house, so no electricity will pass through the electric meter on very sunny days. The panels provide more energy than we can use inside the house, so the excess is sold to the grid. It is net metering, more advanced systems will use a battery bank which requires a charge controller. The solar modules will charge the batteries and power the appliances, but when the batteries are full, the excess energy is sold to the grid overnight, the batteries power the house. Until they run out at this point it is necessary to purchase electricity from the grid, in the event of a power outage the batteries will power the house until they run out and then during the day they will recharge.

Solar farms will have multiple rows of solar panels generating much higher voltages, these will then be combined and connected to a large inverter and then power a transformer substation. Here the voltage increases and is then exported to the grid. The problem with solar energy is that the Sun keeps moving, it moves from east to west every time. a single day and in summer it is high in the sky, but in winter it is low, assuming you are in the northern hemisphere. Solar panels work best when they are perpendicular to the sun. We can see with this torch that the light is stronger here, but as it is tilted, the light spreads over a larger area, so it is less intense.

Ideally we would move the solar panels with the Sun, but this is difficult and expensive, so we must evaluate the location to determine the altitude and azth. Sun at that latitude, then we have to check the shadow and then we choose the best orientation and tilt angle for the module. This involves a lot of data tables and math, which is time-consuming, but with PV Case, our sponsor, you can simulate the real location. Using next-generation AutoCAD-based PV software that incorporates 3D survey data points so you can prototype the design, route electrical wiring and cable trays, and evaluate inverter placement, routing and cabling is completed.

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Solar cells look different, there are crystalline types and thin film types. Where have you seen them used? Let me know in the comments section below. One of the most common is the polycrystalline cell. It generally has these blue scales, although we can obtain other colors such as. this Emerald version these flakes are individual silicon crystals poly, which means many and crystalline, which means crystals, they look beautiful, but each crystal is a separate group of atoms in different orientations, the boundaries of the crystals are defects and in They actually reduce the efficiency of the cell, these are very common in solar-powered integrated circuit electronics products for hobbyists and also in solar panels.

They are relatively cheap but have an efficiency of around 13 to 17%. To make them, we basically take some silica sand and some carbon, like coal, and melt it in an electric arc furnace. It cools and forms these big chunks of raw silicon. This is a piece of raw silicon in my hand. It's very light and you can see it's very shiny. I'll leave a link in the video description to find out where some of these chunks are ground up. powder are mixed with hydrogen chloride and boiled until a gas is obtained, then the gas is distilled to remove impurities and then enters a reactor and accumulatesslowly on the surface of the rods forming pure silicon.

The pure silicon rods are then broken and melted and then cooled to form ingot blocks as the material cools, the atoms bond and form crystals. The blocks are then cut into thin sheets and used as solar cells. This is a monocrystalline cell, it is rigid and usually has a black or very dark blue color. color without visible crystals mono means that the atoms form a very ordered structure monocrystalline is more efficient by 15 to 19%, but it is also more expensive to produce since it is more refined chunks of pure silicon are placed in a crucible and melts a seed The crystal is introduced into it and the silicon atoms begin to adhere to it, then it is slowly extracted and as it cools it forms an ingot.

The atoms are perfectly structured in this process, forming a giant crystal. The ingot is then cut into blocks and then into thin pieces. slices to form the solar cells we can also get thin film types this monocrystalline version is flexible just like this polycrystalline version they are often used for curved roofs or vans and boats it has a shorter lifespan and is less efficient this garden light and This calculator use thin film amorphous silicon which has this brown color, the atoms have a random structure with no defined pattern, they are very cheap to produce, but only 5-8% efficient.

When we talk about efficiency, we are referring to the energy of the Sun and how much it is. Converted into electricity, the energy travels in waves. The waves are of different sizes, from small high-energy gamma rays to large low-energy radio waves, but most of their emitted energy is in the ultraviolet visible and infrared region. The visible spectrum is what the human eye can see. The wavelength determines what color of light the eye will see if we measure the energy per area per wavelength in space we see a curve like this, but at sea level it looks more like this and that is because the atmosphere has absorbed and also diverted some of the energy.

Remember that inside the solar cell we need a photon to remove an electron from the silicon atom. We use silicon because the electron in the outer venous band only needs to receive about 1.1 electron volts to make the jump to the conduction band and then be released from the atom which is equal to a photon with a wavelength of about 1,127 nanometers. what's here. In appearance, any wavelength beyond this therefore cannot be used to generate electricity with this material, but all wavelengths below this can be used; However, the wavelengths have more energy than necessary, so this excess energy will be wasted heating the solar cells, so there is only about 30% left that can actually be used to generate electricity with silicon.

Some of this energy will be reflected. Dust and dirt on the solar panel will also block some of the energy as well as the solar cells heat up from the heat. The wasted energy will decrease the efficiency and after having generated all that energy, we will also have power losses from the inverter and also from the cables, so this red LED cannot power itself. It has a wavelength of around 705 nanometers which provides 1.75 electron volts which we only need. 1.1 and therefore the rest of this energy will be wasted as heat, but to produce the light we consume 4 Ms and only about 10% of that will be converted back into electricity, so we would need about 10 LEDs to power only one LED.

I have tested it here and 9 LEDs are enough to produce light. LEDs also use silicon and so do diodes. A solar cell is basically just a giant flat LED that works in reverse. In fact, we can illuminate an LED and it will produce a voltage check. Watch our LED video to learn how they work in detail. When we look at silicon atoms, they have 14 electrons with four in their outermost shell, known as the venous shell. Silicon atoms are most stable when they have eight electrons in their venous shell, but they only have four and so they will share one electron with each of their neighbors to achieve this, so where do the three electrons and the holes for the electrons come from? ?

We add some phosphorus to one side because it has five electrons in the outermost shell, four of these will be shared and now there is a spare electron that is free to move around the material for the holes, we add some boron to the other side because it has only three electrons in its outermost shell, there are not enough electrons to share and therefore there will now be a gap where an electron can fill, so now we have a shell with too many electrons and also a shell with too few electrons that joins to form the junction PN n means negative because the electrons are negatively charged and P means positive because Therefore, the holes are considered positively charged in this junction, we get a depletion region through which some of the electrons are move and some of the holes move too but this will form a barrier with a slightly positively charged region and a slightly negatively charged region, this creates an electric field which prevents any more electrons or holes from moving and that is what forms the region depletion where no free electrons or holes can exist when light shines on the solar cell, the photons penetrate through the thin N-type layer and reach the PN junction if the The photon has enough energy to knock an electron out of an atom in this region, releasing it and leaving a hole for the electron.

Remember that no free electrons or holes can exist in this depletion region, so the electric field attracts the free electron towards the N-type shell. In the shell, atoms share electrons, so another one will move from the p-type shell to fill this hole, but this only leaves another hole behind, which also fills quickly, so as the hole moves down through the p-type layer, a large number of electrons and holes will accumulate. In both materials at their terminals, this causes a buildup of positive and negative charge and this is what creates the voltage. Free electrons are attracted to the electron holes.

Think of them as opposite ends of a magnet that attract together, so if we provide a path. The electrons will then flow through the wire to reach the other side of the solar cell, where they can recombine with a hole. Light falling on the solar cell will cause a large number of electrons to be released. All of these will flow through the wire and a current. It develops as soon as the light hits the solar cell, the electrons will flow continuously, therefore we have generated DC electricity and this is how a solar cell works. Watch these videos to learn more about engineering and I'll see you there for the next lesson. forget to follow us on Tik Tok Facebook Instagram LinkedIn and of course on engineering mindset.com