Corrosion on solar panels. High-quality photovoltaic panels from reputable manufacturers last at least 25 years reliably. However, modules from less well-known manufacturers often fail quickly. This is usually caused by corrosion on the solar cells.
It is commonly believed that the formation of rust is unique to ferrous metals. In practice, this is not the case, as the integrity of the conductive pathways can be not only oxidative, but also electrochemical in nature.
Corrosion on solar panels – causes.
The main problem with any SES is the need to place the modules outdoors. For this reason, the panels and fasteners themselves are constantly exposed to negative environmental influences.
The slightest breach of seal causes moisture to enter the conductive tracks. Metal and water create a classic galvanic element, as a result:
-the moisture begins to act as an electrolyte;
-nearby metals of different types become a cathode/anode pair;
the less electrolytically stable metal begins to lose electrons and -decomposes;
-conductive busbars or fasteners become inoperative.
How to avoid corrosion on solar panels.
To avoid such a scenario, manufacturers use the following techniques:
-Avoid combining metals with significant differences in electrochemical potentials, e.g. aluminium and copper.
-If it is not possible to use only one material (in welding or threaded joints), the closest pairs in terms of this parameter are selected. This minimises the risk of galvanic reaction.
-Design solutions are created which allow for the use of insulating gaskets at the most risky locations.
-In order to prevent moisture from penetrating the metal, surfaces are painted with water resistant paints.
-The last method is chrome plating or galvanising steel and anodising aluminium.
Advantages of different solar panel corrosion protection coatings.
1. Painting is the simplest and most effective method of protection. It is inexpensive and can be done by the owner of the solar plant himself. It is sufficient to periodically renew the paint layer on the exposed surfaces and the metal structures, which are protected against moisture, will survive the photovoltaic panels for a long time. There are no restrictions on application depending on the material. The recommended coating thickness is at least 1.5-2.0 mm.
2. Anodic oxidation. Used as an anti-corrosion agent for the most electrochemically unstable element, aluminium. To prevent the metal itself from becoming an electron-emitting anode, a surface oxide layer takes on this role. The technology is reliable and sufficiently long-lasting.
3. Galvanising. The frequent use of zinc to prevent corrosion in solar panels can be explained by the fact that it is the lowest in the electrochemical series. Contact with moisture is detrimental to this metal, but it does not affect the layer underneath it. The method is considered ideal because of its versatility, reliability and ease of renewed protection through inexpensive cold galvanizing. The zinc coating thickness is approx. 0.75-0.85 mm in moderate climates, and 1.0-1.2 mm in regions with high humidity and/or aggressive substances.
4. Gaskets made of rubber and polymers. Non-metallic gaskets are used successfully to prevent corrosion in solar panels. They are most often used at the bolt fixing points. The rubber or polymer gasket has the advantage of fulfilling two protective functions simultaneously:
-it ensures a complete watertightness;
-does not compromise the integrity of the joint due to its high elasticity.
5. Other corrosion protection technologies. The most common corrosion prevention technology today for solar panels is frameless modules. They completely eliminate the main vulnerability of the panels – the connection point between the working part of the module and the frame.
This technology is widely used:
In almost all second-generation panels based on rare-earth metals;
100% of third-generation batteries, which are flexible films printed on a 3D printer and filled with a transparent polymer.
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