Multiyear Study of Crack-Induced Degradation in Fielded PV Modules
DuraMAT is studying the effects of cell cracks on power production in modern photovoltaic (PV) modules with thinner cells, new solder processes, glass/glass construction, and 12–20 busbars.
Cell cracks were introduced on approximately half of the 104 modules deployed outdoors. Each module is monitored using a high-accuracy current-voltage curve trace every 30 minutes.
In older modules with thicker cells, glass/backsheet construction, and 3–5 busbars, cell microcracks were easy to create and had real effects on power production. Now, cell cracks have minor (estimated <10%) effects on power production, as will be determined in this study. However, we find significant (1%–3%/yr annualized) open-circuit voltage degradation over the first 5 months of deployment. This voltage degradation is caused by cell design and not the presence of cracks. High voltage degradation is a big risk for the current generation of PV modules.
The PV industry has two outdated assumptions: cell cracks are a big risk to power production, and outdoor degradation of new n-type modules will be similar to what has been observed for passivated emitter and rear contact (PERC) modules.
Core Objective
Team Members
Anubhav Jain and Baojie Li at Lawrence Berkeley National Laboratory; and Todd Karin, Fabrizio Farina, and David Delong at Kiwa PV Evolution Labs (PVEL)
Impact
Using high-accuracy current-voltage tracing in an outdoor deployment with the newest crop of commercial modules, we take a first look at degradation processes in modern tunnel oxide passivating contact (TOPCon) and heterojunction technology (HJT) modules. These results will determine reliability risks and identify avenues for future study.
Learn More
Datasets are available upon request.
Karin, Todd, Tristan Erion-Lorico, and David Delong. 2023. “What Happens When Installers Walk on PV Modules?” PVEL YouTube video.
Contact
To learn more about this project, contact Todd Karin, PVEL
Open-circuit voltage degradation is large over the first 5 months of fielding. Degradation rate varies by bill of material (BOM) between −0.8%/yr and −3.3%/yr.
The DuraMAT cracks and n-type field aging outdoor array (one of two rows).
