A photovoltaic panel is made up by a group of solar cells connected electrically among them by series and in parallel until they reach the suitable voltage for their use.

This group of cells is surrounded by some elements that protect them against external agents as well as rigidity in order to couple with the structures that support them. These elements are the following:

• Encapsulant: made of a material that must present a good radiation transmission and low degradability in front of the action of solar rays.

• Outer cover: de vidrio templado, que, aparte de facilitar al máximo la transmisión luminosa, debe resistir las condiciones climatológicas más adversas y soportar cambios bruscos de temperatura.

• Back cover: usually made up of several opaque coats that reflect the Light coming through the interstices of the cells and making them hit on them once more.

• Metal frame: usually made of aluminium which ensures rigidity and seals the group and which has the necessary elements (generally drills) for the assembly of the panel on the supporting structure.

• Terminal box: it is fitted with the terminals for the connection of the module.

• Protecting diodes: they prevent the surface of the panel to suffer any damage due to partial shadows.