How do solar battery work?
2023.Aug
31
Introduction
On the Earth's surface, there's a lot of energy: about 173,000 terawatts. If we calculate how much energy is used by the entire population of the planet, this number increases by a factor of more than 10,000. In order to make full use of solar energy, let us see, how does a solar cell work? And how is this energy converted into electricity?
How Solar battery Operate
A solar battery is a system consisting of a large number of related photovoltaic cells. They are usually made of semiconductors, the most common of which is silicon. In a battery cell, crystalline silicon sits between two layers of different conductivities, with each atom connected by strong bonds to four adjacent layers. These links hold electrons and don't allow current to flow. So how a solar cell works: electrons transition from a layer with an excess of electrons (n-type) to a layer with defects (p-type), in this transition we call it a pn junction, one side forms a positive charge and the other negative charge on one side.
Sunlight is a stream of tiny particles, namely: photons. The photons collide with the photocells, "kicking" the electrons from their junction, leaving a hole in their place. Due to the electric field effect of the p-n transition, the negatively charged electrons move towards the positively charged holes. Therefore, mobile electrons accumulate on the surface of the battery. They then flow along the external circuit to the opposite layer, performing electrical work at the same time.
One such photocell has a power of 0.5 watts. Combining batteries into modules can increase the power of the battery, such as 12 batteries is enough to charge a mobile phone, of course, if you want to power the whole house, then you need many such modules. Solar cells can work for decades because the only moving elements in their design are electrons, and they keep coming back to where they came from, meaning nothing is wasted or worn out.
(1) This decision will not only be influenced by politicians, but also by leading companies. In addition, there is also a physical problem: solar energy cannot be evenly distributed on the surface of the earth. This is much less the case on cloudy days or at night, for example. That means more effort is needed to produce more efficient batteries, as well as create the infrastructure to store the generated energy.
(2) The effectiveness of the photovoltaic cell itself still raises many questions. If the sunlight is not absorbed but instead reflects off the surface of the cell, or if the electrons return to the holes before passing through the circuit, the photon's energy is lost. Currently, the most efficient cells have an efficiency of 46%, and most factories are less efficient - around 15-20%.
At the current level of solar technology development, humans can still provide energy to the world. It's just a matter of financing, creating the necessary infrastructure, and finding enough space. According to preliminary calculations, an area of hundreds of thousands of square kilometers is required to install the batteries. But in fact, such an area is hard to find.
Hundreds of millions of people around the world, especially in less developed countries, lack access to reliable energy. In many of these countries, the sun is actually plentiful. Therefore, in these places, solar energy will be cheaper and safer than alternative energy sources such as fuel.
Epilogue
Every year, solar panels get better, cheaper, and more competitive with existing energy sources. In the near future, perhaps this technology could revolutionize the landscape of our planet. look forward!
