New Corrosion Mechanism Observed at Ag/Al Metallization of n-type Bifacial Solar Cells

The corrosion mechanism of Ag/Al metallization used on the p+ emitter side of an n-type bifacial solar cell was investigated. After performing a high-temperature and high-humidity test on the module to reduce the output, the Ag/Al metallization was observed. The results confirmed not only corrosion of the glass of the metallization but also the corrosion of Al. It is considered that the corrosion of Al is accelerated by the galvanic potential generated between Ag and Al in the metallization. It is also suggested that the electrons generated by the ionization of Al precipitated Pb around the metallization.