Migration of Sn and Pb from Solder Ribbon onto Ag Fingers in Field-Aged Silicon Photovoltaic Modules

Wonwook Oh,Hae-Seok Lee,Yoonmook Kang,Seongtak Kim,Donghwan Kim,Soohyun Bae,Sung-Il Chan,Nochang Park

doi:10.1155/2015/257343

Abstract

We investigated the migration of Sn and Pb onto the Ag fingers of crystalline Si solar cells in photovoltaic modules aged in field for 6 years. Layers of Sn and Pb were found on the Ag fingers down to the edge of the solar cells. This phenomenon is not observed in a standard acceleration test condition for PV modules. In contrast to the acceleration test conditions, field aging subjects the PV modules to solar irradiation and moisture condensation at the interface between the solar cells and the encapsulant. The solder ribbon releases Sn and Pb via repeated galvanic corrosion and the Sn and Pb precipitate on Ag fingers due to the light-induced plating under solar irradiation.

Highlights

Investigations of the degradation of photovoltaic (PV) modules have been widely performed under various conditions to provide the insights for enhancing the reliability and durability of PV modules [1,2,3,4]
We studied the electrochemical reaction between the SnPb solder and the Ag fingers of crystalline Si (c-Si) solar cells that had been field-aged for 6 years
A mixture layer of Sn and Pb was observed on the Ag fingers at the edge of the solar cells

Summary

Introduction

Investigations of the degradation of photovoltaic (PV) modules have been widely performed under various conditions to provide the insights for enhancing the reliability and durability of PV modules [1,2,3,4]. We studied the electrochemical reaction between the SnPb solder and the Ag fingers of crystalline Si (c-Si) solar cells that had been field-aged for 6 years. Layers of Sn and Pb were found on the Ag fingers down to the edge of the solar cells whereas they were not seen in the samples tested under the standard DH conditions. The Sn and Pb layers are the result of the migration and the deposition of the elements from the solder ribbon due to the repeated galvanic corrosion and the light-induced plating. The implication of this finding for the reliability of PV modules is discussed in this study

Experimental Procedure

Results and Discussion

Conclusion