Avaliação experimental do desempenho da degradação de módulos fotovoltaicos de si cristalino após 15 anos de exposição em campo

Abstract

This paper presents the results of the investigation of performance losses of photovoltaic crystalline-silicon modules in Brazil and the identification of durability issues. The PV-modules were located in northern and eastern regions of the state of Minas Gerais, with the oldest module 20-years in operation. These areas are considered subtropical climate zones, with dry winters and rainy summers. The techniques used were: (1) visual inspection procedures to identify the majorPV module degradation modes, (2) I-V characterization by solar simulator for the electrical characteristics, (3) IR imaging for hot spotsidentification, and (4) Infrared spectrometry by attenuated Total Reflectance (FTIR-ATR) for the analysis of encapsulant degradation. A discoloration and gradual delamination of the encapsulant is attributed to the high incidence of ultraviolet radiation and high temperatures. Extensive mechanisms of encapsulant degradation were analyzed and identified. The detachment ofthe encapsulant was followed by delamination and interconnect corrosion. This paper presents detailed analyses of the operation and reliability of crystalline silicon modules after 15 years in the field. Importantly, these studies provide comparisons between c-Si modules installed at the same region, under the same climate conditions. One set suffers extensive encapsulant degradation — and the other ones, none. The reasons for this are explained.