Shadow influence on Thin Film VS Crystalline Silicon PV Modules

[solarzz]

Hello everyone,

I am recently doing some research and study involved with shadow influence on PV modules for my class.
One thing caught my interest is; I was told because of the technology and the different structure of bypass diodes, thin film solar cells are usually considered to be less susceptible to shadow compare to C-Si cells.
I know this might be true, but does anyone know actually how good thin-film works under partial-shading conditions?
Some people said, thin film is good enough only to loss 20% of it's original power under a 20% shading environment?
which is not near possible when talking about C-Si.
Is this true?


Thanks

[PNjunction]

Right - quite simply you have short term and long-term issues.

Cover a crystalline panel with a very small partial shadow, and the panel has very low output. Cover a thin-film with a partial shadow and only that part under the shadowed condition stops producing. HOWEVER, that is in the short term. The long-term problem is that the areas in thin film that are shaded are now "reverse-biased" which are not healthy for the panel.

Over the life of the panel, say when just camping for the weekend, this partial covering may not cause immediate or permanent damage. However, fixed installations may be another story where consistent reverse bias damages the thin film. You can run this experiment for yourself by purchasing your own crystalline and thin-film panel and measuring the current.

The only thing you can do is put bypass diodes in your string of panels, but within the individual thin film panel itself, it does not accommodate the insertion of bypass diodes.

If you search for "thin film degradation", you'll find studies by Stanford university and others which go into it in much more detail.