Solar energy is the main energy source sustaining life on planet earth and extending its usefulness to fulfill human needs is one of the research priorities around the world. Use of solar power as an alternative energy source have been studied for many decades and at present it has been successfully utilized from powering the smallest electrical device to the largest satellite station in the orbit.
Although the researchers are still striving to achieve the maximum efficiency in utilizing solar energy as electrical current, the basic concept in achieving this would be the same. In order to convert solar energy to electric current, one should make use of a ‘solar panel’ to absorb the sun light, a ‘solar cell’ to convert the absorbed energy into a electric current, and a battery to store the produced current for future use.
When sunlight strikes the solar panel, it can absorb a certain amount of light in the form of solar energy. In scientific terms, these pockets of solar energy are known as ‘photons’. These photons have the distinct ability to displace or ‘shake’ the electron arrangement around the nucleus of an atom in semi-conductor materials.
Thus, the solar powered batteries and devices make use of semi-conductors made out of silicon, which will respond to the striking forces of photons by releasing the electrons from its nuclear orbit. The scientific community knows this effect as the ‘photoelectric effect’ and it forms the basis for generating electricity from solar energy.
When electrons are displaced from its nuclear orbit, the electro-magnetic forces within the semi-conductor will displace them further towards one direction and this will lead to polarization of a cell enabling generation of electric current.
Due to the small amount of current or voltage produced by a single cell, there may be a necessity to use multiple solar cells to generate enough electricity to power the intended device or devices.
When the energy conversion takes place at solar cells, the generated electric current can be directed towards a battery, either chemical or lithium-ion, to replenish its electrical potential and therefore the ability to power an external device or recharge another battery. The re-charging process of a solar powered battery follows the principle of reversing the flow of electrons either through a chemical reaction or by exchanging ions between lithium and carbon depending on the type of battery used.
However, it should be remembered that, solar powered batteries require maintaining its electrical potential for a longer period than an ordinary battery. Thus, the solar batteries are made to give out only a smaller current at the beginning and sustain it for a longer period whereas other batteries will discharge a larger electrical current at the beginning for a shorter duration.