A solar cell module converts sunlight into electricity in the form of direct power and differs from the solar collectors, where solar radiation is used to simply heat the liquid. The conversion of solar energy into electrical energy in solar cells is made with no moving parts, without any need for fuel and without causing pollution.
Today the most common type of PV-module is made out of a thin slice of silicon, which is the same material used in microelectronics. The silicon discs are typically 6 × 6 ” (inch) and just a few tenths of a millimeter thick. Networks of thin metal contacts cover a few percent of the cells front side, i.e. the side being exposed to sunlight. The cell’s back is completely covered by a thin metal layer.
When sunlight becomes electricity
When sunlight hits the module, an electrical potential between the cell’s front- and back side is created, which allows one to get a flow of electrons if you connect a wire between the front and rear metal contacts. By allowing the electrons to pass through an electrical device on its way back to the solar cell, such as a lamp or a radio, it is possible to take advantage of the produced electricity.
The electrical current from a single solar cell is less than one half volts. Solar cells are therefore rarely sold one by one. Usually, 60 cells are connected in series in a weatherproof and sturdy device called a solar cell module, or a PV-module. The front of the module contains a disc of toughened glass, which protects the cells against wear. The back consists of UV-resistant materials and has a glass frame around the edge, mostly made of aluminum. Many manufacturers guarantee 25 years durability of the modules.