CEA Finds Massive Increase In Solar Cell Microcracks

• CEA has compiled the results of a field and EL analysis it conducted for over 300,000 modules at 150 project sites 
• The most significant concern was the increase in microcracks that swelled 47% between 2022 and H1/2023 
• Module procurement from new and inexperienced suppliers in the face of supply chain challenges is compounding the problem 

Clean Energy Associates (CEA) claims it has observed a massive increase of 47% in microcracks in its analysis of solar PV modules, between 2022 and H1/2023. It spans both line cracks and complex cracks, according to the CEA's latest report that argues that undetected damage in PV modules continues to pose a significant risk to the solar industry. 

The report summarizes electroluminescence (EL) analysis conducted by the CEA on over 300,000 solar modules in the field at 150 project sites in 16 nations. 

Specifically, line cracks were seen at 83% of the sites covered, which could be because of wafer issues, light impacts to the cell/module, or pressure on the cell during the stringing or lamination process. 

About 73% of the sites had soldering anomalies that are indicative of poor soldering process control during manufacturing. It occurs when one or more of the busbars are not adhered properly. 

Microcracks can also grow over a module's life, isolating part of a cell and reducing its performance, leading to module hotspots. Extreme weather events also pose threat to modules.

CEA's findings also pin complex cracks at 76% of the sites ,which could be due to stress on module from handling, severe weather or the tools used during installation, hail storms or debris, all of which can lead to hotspots and therefore thermal damage. 

Edge ribbon cracks that CEA affirms it discovered on 29% of the sites covered form where the interconnect ribbon or wire crosses the edge of the cell. Half-cut cells stand the highest risk from these cracks since the field team found 81% of the sites with half-cut cells with this defect. 

CEA analysts believe edge ribbon cracks are more likely to grow compared to other kinds of microcracks. 

While EL testing is required to detect solar cell and module defects in a controlled environment, the top defects visible to the naked eye that the CEA found ranged from the use of foreign material to laminate bubbles. Most of these visual defects, as the CEA calls them, occur during manufacturing. 

Analysts argue that while damage and defects can occur throughout the entire module lifecycle, several module buyers are procuring from new and inexperienced suppliers due to supply chain challenges. These lead to increased quality issues. 

Glass breakage is also on the rise with the increased use of glass-glass technology, while poor installation can also be detrimental to modules. 

To deal with these challenges, the CEA recommends, "A robust QA (quality assurance) process by a third-party inspector during module manufacturing will help prevent manufacturing defects that can lead to underperformance." 

Additionally, developers must opt for pre- and post-installation inspections to ensure defects during shipment are identified before installation.  

The report is available for free download on CEA's website. 

Leading solar PV industry players recently came together for the TaiyangNews Virtual Conference on Reliable PV Module Design to discuss reliability challenges for solar modules and how they are dealing with the same during manufacturing (see TaiyangNews Reliable PV Module Design Conference).