Photovoltaic Module Based On PID (Potential Induced Degradation) Research

With the further development of solar photovoltaic industry, photovoltaic modulesare put into use on a large scale, especially more and more large-scale photovoltaicpower plant put into operation after three or four years of operation, some powerplants in some areas had large generating capacity to reduce the size of thephenomenon, especially in hot and humid place; from the photovoltaic moduleappearance, some modules appear to be signs of corrosion, but a considerable part ofthe appearance of the module without any exception; from the power attenuation ofobservation, the decrease in power beyond the natural optical attenuation, and theattenuation trend is no rule to follow; from measurements of the electrical propertiesof EL picture can be seen, some cells appear black phenomenon, black phenomenonis particularly serious in the module fringe. By industry experts and engineering andtechnical personnel in long-term experiments and field on the failure mode offollow-up study, the mysterious veil of the undesirable phenomenon is slowlyopened, the staff said that the effect of evoked potentials (PID, Potential InducedDegradation attenuation). As the PID phenomenon more and more, the batteryindustry, module manufacturers, installers and customer power system pays moreand more attention to PID. PID causes of photovoltaic power plant occurredcontinuously reported substantial attenuation after three or four years in the work,everyone began to discuss the cause and prevention method of PID. Some countriesand regions have gradually started to put one of the requirements of anti-PID as keymodules of photovoltaic, even more users in Japan explicitly requests to anti PIDin contract, and random sampling; European buyers also itch for a try demanding thesame. This trend also makes more and more domestic and foreign PV power stationunit owners, photovoltaic cells and modules factory, test unit and material suppliers,research on PID is more and more thorough. In this paper, combined with theoreticalknowledge of photovoltaic industry, technology of manufacturing plants and theactual operation of photovoltaic power station, from the basic theory of the photovoltaic field, production technology, material characteristics, the characteristicsof PID, analysis of the causes, solutions and prevention methods and other aspects ofPID are exactly described in details.