Electroluminescence imaging – EL photos, is the technology that allows to penetrate inside the PV modules and detect any invisible defects. Such defects cannot be detected with bare eyes or by any other means such us thermography or I-V characteristics.
Electroluminescence is such an X-ray photo, and shows the inside defects of the PV modules (solar cells), such as cracks, micro-cracks, disoldering problems, etching and dead cells.
Such invisible internal defects, probably in the beginning cannot influence the power output of the PV module. As the time passing combined with the environmental influences, such defects are enlarged and cause problems to the modules. Especially, the micro cracks and disolderings can create hot spots or burn out the modules.
Micro cracks and disolderings on modules, can be formed during cells production process, modules assembly and encapsulation, transportation, installation, lighting and hailstorms, heavy snow as well as and also bad maintenance of the park.
For the brand new PV parks, in many countries recently, investors special with large-scale PV projects demand EL photos for the entire number of PV modules from independent company before commissioning. In that way, investors know exactly the inside quality of their PV modules and the quality of the investment. If there are some problems, investors can take from the beginning the right actions. Also investors create from the beginning an EL photo reference for the PV plant, for future use for insurance companies.
For operating PV plants, the creation of EL photos reference, are very useful too, for the investor. He knows the quality of his modules inside and also creates EL Photo reference for insurance companies, in order to refer or claim things.