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How Solar Panel Works

The contribution of solar energy to the world's total energy supply has increased significantly over the past two decades. This content will show how solar cells or photovoltaic cells generate electricity.

What is Solar Cell?

The energy from the sun is the largest and most fully available energy on the planet. To use this energy we need the help of sand, the second most available element on earth. For use in solar cells, sand must be converted into 99.999% pure silicon crystals. To achieve this, one has to go through a complex process of sand cleaning.

Raw silicon is converted to gas silicon. It is then mixed with hydrogen to form polycrystalline silicon. It is in the form of silicone rings, which are cut into very thin pieces Called silicon wafers.

This is the heart of the silicon wafer photovoltaic cell.

Structure of Solar Cell:

When we analyze the structure of silicon atoms, you can see that they are bound together.

When you are attached to someone, you lose your freedom. Similarly, in a silicon structure, electrons do not have freedom of movement. To make the study easier, let's consider the structure of silicon crystals. Phosphorus atoms with five valence electrons enter the silicon crystal structure. Here an electron is free to move. In this structure, when the electrons receive enough energy, they will move freely. Let's just look at this type of material.

How to create a solar cell:

Let's try to create a very simple solar cell. When light hits them, the electron photons will receive energy and be free to move. However, this movement of electrons is random. As a result, no current passes through the load.

PN junction is a simple and practical way to generate driving force.

N-type Semiconductor:

Let's see how PN junction produces driving force. Like N-type doping, if you insert boron into pure silicon with three valence electrons, one hole is formed in each atom.

 

P-type Semiconductor:

This is called P-type doping if these two types of doped substances are combined. From N, some electrons will move to the P region and fill the holes available there. This creates a depletion region where there are no electrons or holes. Due to the transfer of electrons, the N side gets a slightly positive charge. And the p side becomes negatively charged. Is there will definitely be an electric field between these charges. This electric field produces the necessary driving force.

PN junction:

Let's look at it in detail. Something very interesting happens when light hits the PN junction. The light hits the N region of the PV cell and reaches the depletion region.

This photon energy is enough to produce a pair of electron holes in the depletion region. The electric field in the depletion region pulls electrons and holes out of the depletion region.

Here we observe that the excess of electrons in N region and the holes in P region become so large that a potential difference will be created between them.

As soon as we connect any load between these regions, electrons start flowing through the load. The electrons will reunite with the holes in the P region after completing their path. Thus a solar cell gives a constant direct current.

 In a practical solar cell, you can see that the top N layer is very thin and heavily doped. The P layer is thick and lightly doped. This is to increase the efficiency of the cell. Observe the formation of the depletion region here.

You should note that the thickness of the depletion region is much greater here than in the previous case. This means that due to the collision of light, pairs of electron holes are formed in a wider area than in the previous case.

As a result, more current is generated by the PV cell. Another advantage is that the thin top layer allows more light energy to reach the depletion region.

How to make the Solar Panel:

Now let's analyze the structure of solar panels. You can see that there are different layers of solar panel. One of them is cell layer. You will be amazed at how these PV cells are connected. After passing through the fingers, the electrons accumulate in the bus bars. The upper negative part of this cell is connected to the back of the next cell by copper strips. Here, it makes a series connection. When you connect cells connected to these series.

In parallel to other series cells, you get a solar panel. A PV cell produces only 0.5 volts. Series parallel connection. Increases current and voltage values to usable levels. The layer of EVA sheeting on both sides of the cells protects them from shocks, moisture and dirt.

Types of Solar Panels?

Why are there two different types of solar panels?

This is due to differences in the structure of the inner crystal. Poly crystals are based on multi-crystals in solar panels.

If the chemical process of silicon crystals is taken one step further, polycrystalline lines will become monocrystalline cells. Although the principles of operation are the same, monocrystalline cells offer higher electrical conductivity.

However, monocrystalline cells are expensive and thus not widely used.

Solar panels Installation for Homes:

Solar panels on rooftops have the option of storing electricity with the help of batteries and solar charge controllers.

However, in the case of a solar power plant, large-scale storage is not required. Therefore, they are usually connected to the electrical grid system in the same way as the output of other conventional power plants. With the help of power inverters DC is converted to AC and grid is provided.