How do Solar Power Panels generate Electricity?

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How do Solar Power Panels generate Electricity ?

As consumers we are well aware of solar power panels and they are being used in everything from calculators to road signs to space ships and satellites, but how do solar power panels generate electricity?

Few of us could really answer this question. Solar power panels are complex, however we will cover the basics of how they work.

Generatiing Electricity with Photovoltaic Solar Panels

Solar power panels are made of semiconductors or photovoltaic cells, which are made from silicon. When a photon from the sun strikes a cell, it may be absorbed, or reflected or pass straight through the cell.

The photons that are absorbed will knock an electron loose allowing it to flow freely. Free flowing electrons are electrical current that can be drawn off the panel by electrical cables that are attached and stored in batteries.

Pure silicon is not a good material to use in solar panels because of its crystalline structure. In other words, it is difficult for photons to dislodge any electrons from the silicon atoms.

That's why solar power panels are actually made from silicon with impurities added to it, which in turn creates free electrons, which can be activated by the addition of light and heat i.e. photons from the sunlight. Further, the solar cell is made up of two parts.

The first is doped with phosphorus, which has the effect of adding electrons to the mix and is called the N-Type.

The second part is doped with boron, which has the effect of taking away electrons from the mix and is called the P-Type. When these two pieces are placed close to each other, electrons attempt to move from one side to the other creating an electric field between the two.

Generating Electricity from Solar Panels

When a photon hits the panel, it frees up an electron, creating a hole and causing the electrons to flow fill these holes. As the electrons flow, this flow creates current, which can be harnessed and stored in batteries attached to the solar generator system.

The construction of the panel requires six different elements to be added to the panel to finish our discussion regarding how do solar power panels generate electricity. We have discussed two of the elements, the N-Type and the P-type. In addition there is a back contact, and a contact grid that provides structural support. Silicon is also very shiny and reflective. As a result photons would be reflected from the surface and not dislodge electrons to produce current. An antireflective coating is added to the solar cell to reduce reflection to less than five percent. Finally a glass cover plate is added to the top of the cell to provide protective cover from the elements.

Solar power cells can be connected together in parallel to generate useful levels of electrical current and voltage. We already know that some photons will be reflected from the surface, however other photons are in different wavelengths and do not have any impact on the solar cell. There are losses in the system as the current flows along cables and other components. These losses are due to resistance in these components. Design of solar energy collectors for solar powered homes must take into a account these losses to ensure that sufficient electrical power is available for whatever the solar power panel will be connected to.

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How Electricity is generated by Solar Power Panels ?