Solar - The technology:
Photovoltaics (PV) is the direct conversion of radiant energy into electrical energy using solar cells; the underlying physical principle is the photoelectric effect. The direct current generated in this process is usually converted into alternating current by an inverter and fed into the public electricity grid.
Photovoltaic modules are still mostly made of silicon. After oxygen, silicon is the most abundant element on earth. Photovoltaics is the conversion of sunlight into electrical energy. The sunlight is usually captured in a semiconductor and separated into positive and negative charges in an electric field. The energy is then fed to the consumer via two electrodes.
The different types of cells:
Polycrystalline solar cells
Polycrystalline solar cells are made of polycrystalline silicon, as the name suggests. Polycrystalline solar cells have an efficiency of approx. 13-20% *. The advantages of this type are the rather low purchase price and a long service life. Visually, these modules can be recognised by their irregular crystalline appearance. These modules are used where the surface area of the modules plays a secondary role, e.g. on large factory roofs.
Monocrystalline solar cells
Monocrystalline solar cells are the "further development" of polycrystalline solar cells. From the basis of polycrystalline silicon (poly-Si), monocrystalline silicon is grown in a further step (mono-Si). These cells achieve an efficiency of 14-23% * and thus have a greater energy yield with the same surface area compared to polycrystalline cells. Currently, there are no modules on the market that offer a higher power yield. Visually, the modules can be recognised by their dark blue - black colour and the even, uniform surface.
We at Swaytronic use this technology for all our modules.
Thin-film and CIGS solar cells
In contrast to polycrystalline and monocrystalline solar cells, where the solid silicon block has to be cut into thin slices, thin-film modules use amorphous silicon. The material is then vapour-deposited or sprayed onto the carrier material (usually glass/metal) in a process. The advantage is the low weight. The disadvantage, however, is the low efficiency of 10-13% *.
CIGS solar cells are based on thin-film technology, but have a higher efficiency of 13-15% *. This technology has not been on the market for very long, so there is no data yet on service life and power loss.
* Efficiency: The efficiency indicates how much of the available energy is absorbed by the solar cell and converted into energy. This efficiency is determined in the laboratory using a standardised test procedure.
The following table shows an overview of the different cell technologies with advantages and disadvantages:
| Zelltyp | Vorteile | Nachteile |
|---|---|---|
| polykristalline Solarzelle | • preiswerte Fertigung • lang erprobte Technik | • gegenüber monokristalliner Technologie geringerer Wirkungsgrad • entsprechend höherer Flächenbedarf (6-7m2/kWp) |
| monokristalline Solarzelle | • hoher Wirkungsgrad • geringerer Flächenbedarf (5-6 m2/kWp ) • unterschiedliche Farben möglich • lang erprobte Technik | • teure Fertigung |
| Dünnschichtzellen | • preiswerte Herstellung • geringer Rohstoffbedarf • temperaturbeständig flexibles Trägermaterial | • geringer Wirkungsgrad • Teilweise in schwerer Glas/Glas Sandwichtechnologie • hohe Anfangsdegradation |
The structure of a solar module:
A solar module is built up in different layers. Each of these layers assumes its own function.
The top layer (front glass or EFTE coating) assumes the protective function for the solar cells. It regulates the temperature changes and serves as mechanical protection. (snow loads, branches, etc.)
The second layer consists of a plastic layer (EVA ethylene vinyl acetate). This layer makes the solar panel waterproof and protects it from moisture penetration.
The third layer contains the solar cells. These are interconnected with solder ribbons to form a module.
The fourth layer is identical to the second layer and takes over the moisture protection on the back of the panel.
The last layer is the carrier material for the solar cell. This is either rigid or slightly flexible. (Depending on the design)
The different versions:
Rigid solar panels are installed in an aluminium frame. They have very good mechanical protection and are primarily suitable for stationary applications. The weight is rather high due to the use of a front glass plate in combination with the aluminium frame.
However, the aluminium frame makes it very easy to implement systems with a substructure.
Flexible solar panels are very suitable in areas where a low installation height, low weight and flexibility are desired. Due to a semi-flexible front and back, this version can be installed very well on uneven surfaces.
This version is very well suited for mobile applications.
Foldable solar panels consist of different cell modules that can be stored in a very space-saving way. They are unfolded when in use and folded again when not in use.
This design is suitable for situational use.
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Design & Engineering
Benefit from more than 5 years of experience, our portfolio includes smallest projects up to complex large-scale projects for industry and commerce. From the single cell to the complete battery pack. We are happy to design your solution.
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In order to be able to effectively prove the properties and performance characteristics of your product to your customers through recognised labels, we offer a comprehensive service for CE, RoHS, EMC, Battery Directive, UN38.3, DG certification, MSDS etc..
Environment & Sustainability
Our efforts with regard to sustainability go beyond the minimum requirements ofthe obligation to inform and take back our products. Thus, we focus on the entire life cycle of our products.
