What is the meaning of PID effect of pv modules?

What is the meaning of PID effect of pv modules? When referring to photovoltaic modules, it is necessary to pay attention to their two major effects, one is the hot spot effect and the other is the PID effect. Then, what is the photovoltaic PID effect? Following the renewable power system installation company would like to share with us.

The full English name of PID is: Potential Induced Degradation.

Found for the first time in 2005, the company and put forward the PID effect, refers to the components work in high voltage for a long time, in the plate glass, packaging materials, the borders between leakage current, a lot of charge accumulation in the cell surface, make the cell surface passivation effect worse, cause the fill factor and short circuit current and open circuit voltage is reduced, the component performance under design standard, but the attenuation is reversible.

Some studies have also found and explained the PID effect: when photovoltaic modules of PV solar power plants are subjected to negative bias voltage, anode ions (generally Na ions) of leakage current flow into the battery, reducing the parallel resistance of the battery. That is, impurities appear in the semiconductor, which can form conductive channels inside the battery, reducing the current output of the components.

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Third generation photovoltaic modules PID effect: is the cause of photovoltaic modules edges is easy to have moisture to enter, EVA hydrolysis produces acetic acid, acetic acid and Na in the glass reaction, can generate a lot of Na ions move freely, can react with silver grid lines on the surface of the cell, thus corrosion cell gate line, lead to the rise of series resistance, lead to component performance attenuation, the attenuation unrecoverable.

It can be seen that there are two main reasons for the formation of Photovoltaic PID effect of photovoltaic modules:

1. Changes in the electric field of the original PN junction, or the presence of other current channels, will reduce the actual photogenerating current flowing through the PN junction;

2. The device is affected by ion migration, and the material properties are irrecoverable. Compared with the original components, the output power decreases.

At present, according to the causes of photovoltaic module PID effect, although the PID effect can be weakened or avoided from the battery, module and system end, the influence of PID effect is finally reflected in the battery. Therefore, it is suggested that battery manufacturers conduct more comprehensive research on products, combine upstream and downstream, and consider cost-effective solutions as a whole.