On the international market are currently more than 100 manufacturers present, who offer way above than 1,000 different solutions in the area of photovoltaic. Besides the monocrystalline and polycrystalline silicon cells, the thin-film cells are belonging to the mostly used technologies.
The monocrystalline silicon cells are silvery shiny slices with a thickness of 0.2 to 0.3 mm. Basis of the production are single crystals of high-purity silicon.
The monocrystalline cells are requiring higher production costs in comparison with the other cell-technologies because of the special way of being manufactured.
With a current efficiency of up to 20%, an area of about 7-9 m² are necessary to produce 1 kWp.
The polycrystalline silicon cells are inter alia produced by the ingot casting process. In this process the intensely heated silicon is being cooled down in a casting mold, whereby irregular crystals are emerging. Polycrystalline silicon cells are achieving an efficiency of 16% and are less expensive to produce as the monocrystalline cells regarding to the costs and energy.
The thin-film cells, amongst others containing of copper-indium-diselenide (CIS) or cadmium telluride (CdTe), are achieving an efficiency of 9 to 12 %. They are characterized by a slight loss of power if they are exposed to high temperatures and a higher tolerance against shading in comparison to the silicon cells. A further increase of the potential of efficiency of the copper-indium-diselenide cells can be expected.
Choosing the right modules is, besides the technology, also depending on other factors. These include the build quality, seal of approval or certification of the products and manufacturers. These factors are mostly an indication for the performance ability of the offered products. So is, for example, the tolerance of efficiency over ±5%, you should refrain from the purchase to prevent profit cuts.
You should also pay attention on the temperature coefficient as well as on the storm and hail resistance according to EN 61730.
Key standards in the field of photovoltaic modules are amongst others:
DIN EN 61215: Crystalline silicon terrestrial photovoltaic (PV) modules
Design qualification and type approval
DIN EN 61646: Thin-film terrestrial photovoltaic (PV) modules
Design qualification and type approval
DIN EN 61730: Photovoltaic (PV) module safety qualification – part 1: Requirements for construction and part 2: Requirements for testing
DIN EN 50380: Datasheet and nameplate information of photovoltaic modules
A reputable quality label of the branch is:
RAL-GZ 966: Classification and test specification