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Title: Electrochemical mechanisms of leakage-current-enhanced delamination and corrosion in Si photovoltaic modules

Abstract

This paper analyzes the mechanisms for corrosion and delamination observed in Si photovoltaic modules subjected to high temperature and humidity with a negative-ground bias testing. Based on the thermodynamic data, the ionic component of the leakage current causes reduction reactions of water on the cathodic metallization, producing hydrogen gas and hydroxide ions. Ag fingers are strong catalysts for this reduction reaction compared to other materials used in solar cells and can be the initiation sites of corrosion and delamination caused by the electrochemical reactions. The produced hydrogen gas accumulates inside the module potentially producing a high gas pressure that can promote delamination, which is often preferentially initiated on metallization where the adhesion strength is lower [1], [2], [3]. The local basicity near the metal surface increases due to the hydroxide ion generation. Thus, the environment inside the encapsulant can be alkaline despite the presence of acetic acid decomposition products from the encapsulant. Corrosion of materials such as Si used in solar cells occurs and the extent depends on their corrosion resistance to the alkaline solution. This suggests that corrosion and delamination are interactive and promote the formation and propagation of one another.

Authors:
; ; ;
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
OSTI Identifier:
1487328
Report Number(s):
NREL/JA-5J00-68847
Journal ID: ISSN 0927-0248
DOE Contract Number:  
AC36-08GO28308
Resource Type:
Journal Article
Journal Name:
Solar Energy Materials and Solar Cells
Additional Journal Information:
Journal Volume: 188; Journal Issue: C; Journal ID: ISSN 0927-0248
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; water reduction reaction; hydrogen; corrosion; delamination; leakage current

Citation Formats

Li, Jichao, Shen, Yu-Chen, Hacke, Peter, and Kempe, Michael. Electrochemical mechanisms of leakage-current-enhanced delamination and corrosion in Si photovoltaic modules. United States: N. p., 2018. Web. doi:10.1016/j.solmat.2018.09.010.
Li, Jichao, Shen, Yu-Chen, Hacke, Peter, & Kempe, Michael. Electrochemical mechanisms of leakage-current-enhanced delamination and corrosion in Si photovoltaic modules. United States. doi:10.1016/j.solmat.2018.09.010.
Li, Jichao, Shen, Yu-Chen, Hacke, Peter, and Kempe, Michael. Sat . "Electrochemical mechanisms of leakage-current-enhanced delamination and corrosion in Si photovoltaic modules". United States. doi:10.1016/j.solmat.2018.09.010.
@article{osti_1487328,
title = {Electrochemical mechanisms of leakage-current-enhanced delamination and corrosion in Si photovoltaic modules},
author = {Li, Jichao and Shen, Yu-Chen and Hacke, Peter and Kempe, Michael},
abstractNote = {This paper analyzes the mechanisms for corrosion and delamination observed in Si photovoltaic modules subjected to high temperature and humidity with a negative-ground bias testing. Based on the thermodynamic data, the ionic component of the leakage current causes reduction reactions of water on the cathodic metallization, producing hydrogen gas and hydroxide ions. Ag fingers are strong catalysts for this reduction reaction compared to other materials used in solar cells and can be the initiation sites of corrosion and delamination caused by the electrochemical reactions. The produced hydrogen gas accumulates inside the module potentially producing a high gas pressure that can promote delamination, which is often preferentially initiated on metallization where the adhesion strength is lower [1], [2], [3]. The local basicity near the metal surface increases due to the hydroxide ion generation. Thus, the environment inside the encapsulant can be alkaline despite the presence of acetic acid decomposition products from the encapsulant. Corrosion of materials such as Si used in solar cells occurs and the extent depends on their corrosion resistance to the alkaline solution. This suggests that corrosion and delamination are interactive and promote the formation and propagation of one another.},
doi = {10.1016/j.solmat.2018.09.010},
journal = {Solar Energy Materials and Solar Cells},
issn = {0927-0248},
number = C,
volume = 188,
place = {United States},
year = {2018},
month = {12}
}