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How Do Solar Panels Work?
JUNE 15, 2021
You’re probably already aware that solar panels absorb light energy from the sun and convert it into electrical energy. But what happens during the steps in between? How do these blue and black slabs of material produce enough electricity to power entire houses, factories, offices, schools, farms? Let's take a closer look...
Did you know?
The ‘PV’ in solar PV panels stands for ‘photovoltaic’, which literally translates as ‘light to voltage’. What a perfect description!
What are Solar Panels Made Of?
A solar panel is made up of layers of different materials.
In the middle we have the solar cells (1) – these are the bits that actually produce electricity. There’s more on them below.
Surrounding the cells is a layer of rubbery sheeting (2) – it stops dirt and water reaching the cells and protects against vibrations.
On top of that you’ll find a glass layer (3) with a frame (4), and underneath the rubbery sheeting is a back-sheet (5) – these hold the whole panel together while letting light through.
Attached underneath is a junction box (6) – this contains the electrical cables.
If we zoom in, we can see that solar cells are made from tiny individual fragments. These are fragments of silicon…
How Are Solar Panels Made?
The main material used in solar panels is silicon, a non-metal that conducts electricity. Silicon is originally made from sand – yep, just like the kind you’d find on a beach – which has been heated at high temperatures and purified. It’s the same stuff that’s used to make computer chips.
Multiple fragments of silicon are joined together. There are different ways of doing this, and the particular method affects the type of solar cell produced.
In polycrystalline panels (the blue ones), silicon crystals are melted together and poured into moulds, so the fragments set in random directions, giving a splintered pattern. Whereas in monocrystalline panels (the black ones), a block of pure silicon is cut into thin slices called wafers, which are then joined together. This is why monocrystalline panels have a more even look.
The silicon is surrounded by a conductive metal casing to make a solar cell. Multiple solar cells are connected to form a sheet of cells. A sheet is layered in between glass to produce a complete solar panel.
How Do Solar Panels Generate Electricity?
Each solar cell is basically a sandwich made up of two slices of silicon with an ‘electric junction’ in between. This junction contains an electric force strong enough to move any particles that come near it.
- Sunlight hits the solar cell.
- The silicon absorbs photons (tiny particles of light).
- Photons knock electrons (e), tiny particles that carry electricity, off of the silicon.
- The electric junction pushes electrons towards the top slice of silicon and the ‘holes’ where the electrons used to be towards the bottom slice.
- A wire connects the two slices of silicon, allowing the electrons in the top slice to move to the bottom slice to be reunited with their holes.
- This flow of electrons creates electricity, which can be taken away by more wires to power your building.
Solar cells are sealed so that only electrons can get in or out. This means that electrons are the only moving parts in solar panels and never get used up. As a result, solar panels are silent, do not require fuel to work and take decades to wear out.
So that’s the science of solar panels! To make a fully functioning system, multiple solar panels are joined together and then connected to a building’s wiring so that the electricity can be delivered. As you can see, all that solar panels need to operate is sunlight – no fuel is required, making them a completely renewable source of power.
Find out more about how Cactus Energy could help you save money and the planet through a bespoke solar panel installation on your home or business…