The photovoltaic solar panels that are used today are made up of the following structure:
- Front cover
- Encapsulated covers
- Support framework
- Rear protection
- Electrical junction box
- Photovoltaic cells
The most important part of a photovoltaic module is the set of photovoltaic cells that are in charge of transforming solar radiation into electrical energy. The rest of the elements that are part of a solar panel have the function of protecting and giving firmness and functionality to the whole.
Photovoltaic cells are encapsulated with reinforced glass and several layers of plastic material. Subsequently, this whole set is reinforced by forming an outer frame with metal aluminum profiles.
The front cover of the photovoltaic panel has a mainly protective function since it suffers the action of atmospheric agents. Tempered glass with low iron content is used, since it has good protection against impacts and is a very good transmitter of solar radiation.
Although the presence of the cover is necessary to protect the photovoltaic cells, depending on the quality of the protective glass it can lower the performance of the solar panel.
The encapsulated layers are in charge of protecting the solar cells and their contacts. The materials used (ethyl-vinyl-acetylene or EVA) provide excellent transmission to solar radiation, as well as zero degradation against ultraviolet radiation.
EVA is a thermoplastic copolymer of ethylene and vinyl acetate, which acts as a thermal and transparent insulator to let sunlight pass through to photovoltaic cells. It provides cohesion to the panel assembly by filling the volume between the front and rear covers, thus damping the vibrations and impacts that may occur.
The most important problems that copolymers such as EVA present are their excessive plasticity (when stretched, they do not recover their original position), great adherence to dust, which causes a decrease in transmissivity to solar radiation, and their low useful life , which usually conditions the useful life of the entire module.
Other characteristics of these copolymers are:
- Good resistance to weather and chemical agents.
- Low water absorption
- Easy to pick up
- Easy to cut
- It is non-toxic
E l support framework is the part that gives mechanical strength to the assembly. The support frame of a solar panel allows its insertion in structures that will group modules.
The frame is usually made of aluminum, although it can also be made of other materials. In any case, it is important that it be built with a material resistant to different weather conditions.
Rear Protection of a Photovoltaic Panel
Its mission of the subsequent protection of the photovoltaic panel consists, fundamentally, in protecting against atmospheric agents, exercising an insurmountable barrier against humidity. Normally, 24 acrylic, Tedlar or EVA materials are used. They are often white in color as this favors panel performance due to the reflection it produces in the cells.
El Tedlar, also known as PVF, Polyvinyl fluorid, or (CH2CHF) n. Tedlar or PVF is a thermoplastic polymer, structurally similar to PVC (polyvinyl chloride). It has low flammability, low vapor permeability, and excellent resistance to wear from atmospheric conditions.
Electrical Junction Box
Two cables come out of the electrical connection box, one positive and the other negative. It is the place where continuity occurs in the electrical circuit.
Some photovoltaic modules have a ground connection, which must be used in high power installations.
Photovoltaic cells are the most important elements of the photovoltaic panel. These are semiconductor devices capable of generating electricity from solar radiation.
In the manufacturing process of the photovoltaic panel, once the electrical connections are assembled, a very strict quality control is passed, since we cannot forget that they are exposed to the weather for many years in conditions from extreme heat to cold glaciers, wind , humidity, etc.