Degradation of crystalline silicon solar cells

[Mayan Fung]

Hi there, it is commonly accepted that the lifespan of crystalline silicon solar cells is about 20-30years. And they define the lifespan as when the solar cells efficiency drop to about lower than 10%. However, what are the possible reasons for the degradation? I can only find research papers on the efficiency drop in several months, which may be related to some fundamental defaults in the materials. However, seems that no group studies the long-term degradation. Some suggested reasons like the glass covering the solar cells becomes dirty after years, etc.

And I found another research work where the group performed some treatment on the old silicon solar cells (basically cleaning it with some acids and alkalis). They then claimed that the silicon wafer can perform like a brand-new one and be used again in making new cells. If that's the case, that means the silicon part shouldn't change too much after years. That's why I am so curious about why there is such a great efficiency drop.

 

[anorlunda]

Don't you mean drop by 10% rather than drop to 10%?

 

[anorlunda]

A bit of googling found this

https://www.solarpowerworldonline.com/2017/06/causes-solar-panel-degradation/
According to NREL, modules can fail because of unavoidable elements like thermal cycling, damp heat, humidity freeze and UV exposure. Thermal cycling can cause solder bond failures and cracks in solar cells. Damp heat has been associated with delamination of encapsulants and corrosion of cells. Humidity freezing can cause junction box adhesion to fail. UV exposure contributes to discoloration and backsheet degradation. These things just happen, and it’s difficult to determine how bad the degradation will be.

 

[Mayan Fung]

A bit of googling found this

Thanks! That's a very useful article. That also means some of the failures such as cracks cannot be simply fixed by like cleaning the silicon wafer and the silicon wafer can neither perform like a brand-new one just after some kind of simple treatments.