Análise da degradação e sujidade de módulos fotovoltaicos produzidos com células solares de silício de diferentes tecnologias após 6 anos de operação

Abstract

Considering the long-term durability, higher than 30 years, of photovoltaic modules, the objective of this master thesis is to compare and analyze the degradation and the influence of soiling in photovoltaic modules produced with silicon solar cells with and without aluminum back surface field (BSF- Al), after 77 months of operation in a gridconnected photovoltaic system. The solar cells and the 60 photovoltaic modules, of wich 28 were assembled with solar cell without BSF and 32 with BSF-Al, were produced in a pilot scale and installed at the Petrobras University. All photovoltaic modules were characterized in a solar simulator after the manufacturing and after 77 months of operation. Defects were evaluated through visual analysis and the influence of soiling on the electrical parameters of photovoltaic modules after 77 months of operation was analyzed. The degradation of output power and electrical parameters of the photovoltaic modules produced with solar cells with and without aluminum back surface field were also compared. The existence of "snail trails" was found, mainly on the edges of all solar cells, regardless of their structure. The modules produced with solar cells without BSF-Al showed the highest degradation, with approximately 4.7% of reduction in the output power at the maximum power point (PMP) in 77 months of operation. In modules with solar cells with BSF-Al, the PMP drops only 0.3% per year, lower than the values of commercialized modules. In devices with both types of silicon solar cells the soiling produced a reduction in the PMP higher than 2.8%. The electrical parameter most affected by soiling and degradation was the short-circuit current and it was more affected by the soiling than by the degradation.