What to watch out for on the module declarations

For investors, the most important is to choose quality equipment for the construction of solar power plants, so it is important to be familiar with some of the physical and technical principles in order to avoid possible unpleasant surprises. Below are outlined the basic characteristics of LID and PID effects and their impacts on the power of the modules.LID (Light Induced Degradation) effect occurs with the first exposure monocrystalline or polycrystalline solar cells to the UV radiation. Namely, the exposure of the solar cells to the UV radiation leads to reduction of their efficiency resulting with defects related wrinkles and oxygen in the crystal structure of silicon from which are cells made and the defects at the interface of silicon and anti reflective layer of cells (SiN: H-Si compound). Under the conditions of irradiation of 1000 W/m2 LID effect lasts about 72 hours and can ultimately result in less power output standard 60-cell modules for 1-2% or 2-5 Wp compared to its rated power module.

Physical LID effect can not be avoided, but it is possible, which is important for the end user, look for the declared power photovoltaic module that refers to the power obtained after exposure to UV radiation. So the end user could know what is the real power of the modules.

PID (Potential Induced Degradation) effect is associated with a fall in the efficiency of photovoltaic modules. This effect is a consequence of relatively high operating voltage photovoltaic module (600-1000 V). Because of the difference of electric potential solar cell and the module aluminum frame it creates an electric field strong enough to support the flow of electrons from the solar cells within the module. As a result, the efficiency of the module decreases and the possible reduction of module efficiency up to 20%. Elevated temperature and humidity support the negative PID effect.

PID effect can be prevented with proper construction of the module with sufficient spaces and thickness of the layers and the proper selection of materials prevent inducing an electric field which would affect its performance modules.

It is important to choose a module suppliers such as IBC Solar AG. They declare the power of the module upon the completion of LID effect. Specifically, this results in a linear power output guarantee of 100% of the nominal value. In addition, the proper construction of IBC’s the module avoided the emergence of PID effect, thereby ensuring a long-term operation of photovoltaic modules in accordance with the technical specifications of the manufacturer and to the end user are guaranteed optimum performance with minimal loss of efficiency.

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