The sun is the most abundant source of energy. The earth receives almost 173 terawatts of energy from the sun in the form of solar power. This is almost 10 times more energy than the total amount of energy used by the world’s whole population. But then why ain’t we still rely on solar-power fully? To answer this question, you need to know how do solar panels work for your home or for any place.
The solar panels are made up of small solar cells and those solar cells are made up of 2nd most abundant material on the earth, i.e sand or silicon. Let’s see how sands are converted into silicons.
How Silicon Is Made From Sand?
To convert sands into pure silicon, there is a reaction which you need to perform. When sand reacts with the carbon at 2000°C, pure silicon forms. We need to get 99.999% pure silicon from sand to use them in the solar cells.
Now, silicon is formed and we need to use them in the solar cells. The silicon is a semiconductor and the crystalline silicon is sandwiched between two conductive layers to form the solar cells. Let’s see how do we use the raw silicon in the solar cells to generate current.
Raw Silicon Into Photo Voltaic Cell
There is a system to convert raw silicon into polycrystalline silicon. When raw silicon enters the system, it gets converted into gaseous silicon compound form and after this, it gets mixed with the hydrogen and pure polycrystalline silicon forms.
This polycrystalline silicon gets cut into thin plate sizes which are known as silicon wafers. This is the most important part of the photovoltaic cell.
In these silicon wafers, the silicon atoms are bonded together and there is no free electron to move and generate electricity so, we need to inject phosphorous and boron in wafers to have free electrons and holes to produce current.
Making Of N-type Conductor
When we inject phosphorous atoms with 5 valence electrons into the wafers, there is one free electron to move in every atom. This is called an N-type conductor. So, when light energy(photons) strikes on such metal, electrons get excited and start moving here and there but there is no fixed direction of moving and because of this we can’t use those electrons to produce current.
Making Of P-type Conductor
To make the electrons move in one fixed direction, we need a P-type conductor to create a P-N junction. For that, we need to inject the boron atoms with 3 valence electrons so that, there will be one hole left and it will become a P-type conductor.
Depletion Layer Creation
When we keep the N-type and P-type conductors side by side, the electrons from the N region start sliding towards the P region, and holes from the P region start sliding towards the N region. In the middle of two regions, electrons get into the holes, and one depletion region forms in the middle where there are no free electrons and holes available.
As the electrons from the N region moved towards the P region and holes moved from the P region towards the N region, there is a formation of a slightly positive charge in the boundary of the N region and a slightly negative charge in the boundary of the P region.
Because of this negative and positive charge formation, electric field gets produced and this electric field gives the fixed direction to free electrons.
How Does Electric Field Of Depletion Layer Help To Produce Electricity?
When photons of sunlight strike on the depletion layer, the electrons and holes get separated and again and become free to move but this time because of the presence of the electric field, the free electrons go to the extreme end of the N region and holes go to the end of P region.
Because of the presence of charge carriers in the ends of wafers, one potential difference creates and if you connect and bulb wire with two ends, the electron starts flowing thru the wire, and the bulb glows.
One solar cell can give 0.5V only but if you put them together, its voltage will increase. Almost 12 cells together can charge a cell phone. In this way, you need many modules to light an entire house.
In the solar cells, the N region is on the top and the P region places below. Practically the N region is thin(heavily doped) and the P region is thick(lightly doped) so that the depletion region will be bigger and more electric generation will occur.
Because of the bigger depletion region, the light reaches fast and more photons strike the depletion layer so that fast and more electron-hole pair forms.
How Solar Panels Are Formed?
There are almost 5 layers in the solar panel and in middle, there is the layer of cells. There are a lot of photovoltaic cells that are connected with each other with the help of a copper wire in series. When we connect these types of so many series of PV cells in parallel, one layer of cells forms which is present in the middle layer of the solar panel.
There are EVA sheets over and under the cell layer in order to protect it from dust, vibrations, shocks, etc. And finally, on the very top and under, some plastic is there to protect from rain or anything.
Appearance Of Solar Panels
There are two different appearances of solar panels and that is because of the crystalline internal lattice structure. There are two types of solar panels i.e polycrystalline and monocrystalline panels.
If we talk about the polycrystalline panels, the multi crystals are randomly organized, and in the monocrystalline panels, the multi crystals are organized in a particular order.
Note: Monocrystalline cells offer higher electric conductivity but because of its high cost, it is not used widely.
How Do Solar Panels Work For Your Home?
More solar panels mean more electricity. When we use the solar panels on the house roof, it converts the solar energy into electrical energy and stores it in the inverter of our house. And from the inverter, DC converts into AC and finally lights the room.
Reasons Of Voltage Drop
There can be many reasons of dropping the voltage of the solar panels and some of the possible reasons are:
- At high temperatures. (Unlike thermal solar energy, PV works less well when it’s very hot! In tropical climates, choose higher voltage panels.)
- For the long wires. Try to keep the wiring between your panels and other parts of the installation as short as possible.
- Diodes can also cause a small voltage loss.
How To Increase Efficiency Of Solar Panels
There are many ways to increase the efficiency of solar panels and some of them are:
- Buy the panels with high concentrated PV cells
- Don’t install the panels where rarely sunlight reaches
- Take the help of experts in installing the solar panels
- Clean the panels from time to time(if possible)
- Increase the number of hours of exposure to the sun
- Fix the angle where the exposure to the sun will be maximum and light intensity will be high
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