Measurement of internal cell defects in photovoltaic modules

How to detect faults and failures in PV cells and modules?

There are various approaches used for detection of faults and failures in PV cells and modules. These approaches are based on visual inspection, electrical measurements, electromagnetic radiations measurements, and imaging techniques. 6.1. Visual inspection methods

How are PV cell defect detection methods generalized?

Moreover, to generalize the PV cell defect detection methods, this paper divide them into (i) imaging-based techniques, (ii) rapid visual inspection methods, and (iii) I–V curve measurements, which are the most powerful diagnostic tools for field-level testing.

Why is PV cell defect detection important?

Various defects in PV cells can lead to lower photovoltaic conversion efficiency and reduced service life and can even short circuit boards, which pose safety hazard risks . As a result, PV cell defect detection research offers a crucial assurance for raising the caliber of PV products while lowering production costs. Figure 1.

Why do PV modules have defects?

The defects generated during manufacturing phase grow with the passage of time as the PV module is subjected to various kinds of thermo-mechanical loads during subsequent stages of life . The transportation of modules, handling, and installation might become a source of mechanical loads and produce some defects .

Are defects on the surface of abnormal PV cells different from the background?

The defects on the surface of abnormal PV cells were different from the background in the image, but these defects were generally similar in appearance to the background in the EL image, so it was difficult to distinguish them.

How to check if PV module defects are correlated with I–V curve?

Moreover, visually inspected PV module defects, such as panel browning, delamination, and cell damage, provide a good indication of their correlation with the measured I–V curve. The visual inspection method should be carried out following the international standard test procedures, such as IEC61215, IEC61646.