It depends on the type of solar cell you are talking about...
If you have silver on the solar cells then the composition should go something like this. Silver on the front of the panel, then the silicon material, then Al on the back. That is the problem, the Al. So if you crush the material up into a fine powder, you are still dealing with a large amount of Al. And now you are dealing with the silicate material.
Solar Cells can be a pain in the you know what.
The first thing I would do is try to find out what the composition of the material is. It's best to know exactly what you are dealing with before you attempt to process. And unfortunately, there are many different ways to manufacture solar cells, and they have been doing so since the 80s.
So in other words, it's not straight forward and you really need to figure out the composition before you try to recover and silver. There is no one way to process this type of material, and no one way, but many, to manufacture. Many solar cells don't even use silver.
Scott