Comparison of the 60Sn40Pb and 62Sn2Ag36Pb Solders for a PV Ribbon Joint in Photovoltaic Modules Using the Thermal Shock Test

Min-Soo Kang,Yu-Jae Jeon,Young-Eui Shin,Do-Seok Kim

doi:10.3390/en10040529

Abstract

In this study, the characteristics of a photovoltaic (PV) ribbon (t = 0.25 mm) joint with 60Sn40Pb and 62Sn2Ag36Pb solders were evaluated using thermal shock tests. The thermal shock tests were performed under three conditions: −40–65 °C, −40–85 °C, and −40–105 °C. The results of these tests were analyzed using electroluminescence (EL) and cross-sectional images. Following testing, broken metal fingers (MFs) were confirmed near the solder joint. PV module degradation was attributed to the broken finger ratio (BFR) based on quantitative analysis of the dark rectangular (DR) regions on the EL images. In addition, the activation energy of the broken MFs was calculated from the increasing BFR. Thermal characteristic variations due to the added Ag in the PV ribbon solder joints were evaluated through observation of solder micro-structure changes following thermal shock tests.

Highlights

To address energy depletion and environmental issues such as the instability of oil prices, depletion of fossil fuels, and the Fukushima nuclear power plant accident in Japan, more attention is being focused on renewable energy [1,2,3]
We performed thermal shock tests to analyze the degradation of ribbon joint characteristics in PV module solder joints using 60Sn40Pb (SP) and 62Sn2Ag36Pb (SAP)
The thermal shock tests were performed under three conditions, −40–65 ◦ C, −40–85 ◦ C, and −40–105 ◦ C

Summary

Introduction

Among the many types of renewable energies, silicon solar cells have been the most common for industry use due to their low-price and machinability. More than 90% of annual solar cell production is based on crystalline silicon wafers, making silicon wafer-based technology the most important technology for photovoltaic modules (PV modules) [4]. Many researchers have studied silicon-alternative materials and PV module reliability according to constraint properties such as the band-gap energy and efficiency limit. Many manufacturers in the photovoltaic industry offer warranties of 20 years or longer for PV modules with incomplete knowledge of their reliability in the diverse environments in which these modules are typically deployed [6]. A number of researchers have studied the degradation characteristics of PV modules in real-time outdoor conditions.

Results

Discussion

Conclusion