Electrical Signatures of Corrosion and Solder Bond Failure in c-Si Solar Cells and Modules

TL;DR

This paper investigates how corrosion, delamination, and solder bond failures in c-Si solar cells affect electrical performance, providing a unified framework to interpret degradation signatures and guide more resilient module designs.

Contribution

It introduces a comprehensive theoretical framework linking physical degradation mechanisms to electrical signatures, improving understanding and diagnosis of solar module failures.

Findings

Corrosion and delamination cause complex voltage/current redistribution.

Degradation leads to measurable changes in photocurrent and resistances.

The framework helps interpret experimental J-V characteristics related to failures.

Abstract

Moisture- and temperature-activated corrosion of metal fingers, mechanical stress induced delamination, and failure of solder bonds rank among the leading failure mechanisms of solar modules. The physics of moisture ingress, diffusion and reaction have been explored in detail, but the electrical implications of corrosion and delamination on specific front-surface grid geometry is not fully understood. In this paper, we show that the module efficiency loss due to corrosion, delamination, and solder bond failure (CDS) involves a complex interplay of voltage/current redistribution, reflected as a loss in photocurrent as well as decrease/increase in shunt/series resistances. Our work will redefine the interpretation of experimental J-V characteristics features due to degradation mechanisms, integrate a variety of scattered and counter-intuitive experimental results within a common theoretical framework, and inform CDS-resistant grid design for solar modules.