- Sep 12, 2003
- 30
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Recently I purchased some scrap solar cells. I'm attempting to connect the scrap cells together. Soldering works, it makes a low resistance connection, but it seems the solar cells and the solder expand at different rates when heated/cooled, and the solder literally falls off, flux helps, but I'd like a more reliable connection.
I tried some conductive ink, and that worked for connecting the negative traces on the surface of the cells, but conductive ink is expensive and my pen dried up after I drew the first line.
My latest attempt was to use some aluminum foil strips, taped to the surface of the cells. The tape doesn't affect the performance because it is transparent, and it holds the cells together (the panel is somewhat flexible; bonus). But the connection between the cells and the aluminum foil is crappy unless I apply pressure.
The surface of the cells is of course a silicon crystal; the texture is similar to the ceramic on old CPU's.
A quick search on wikipedia gave me these numbers:
Silicon melting point: 1414 C
Aluminum melting point: 661 C
Using a lighter to melt some of the aluminum foil strips, I found that it didn't ball up like solder does, I think my best option would be to melt (bond) the aluminum foil to the surface of the panels. As I type I have a small panel with aluminum foil in a small toaster oven, as close to the element as I could get it, with the temperature cranked to 220 C, but I don't think that will bond the foil to the silicon...
These cells are incredibly cheap because they are scrap cells, a 4"x4" panel would produce 1W of power in a nice sunny day, which translates to about 2W per $1 spent, not including the price of a roll of aluminum foil + picture frame.
Any ideas on how I can get the foil bonded to the surface of the silicon cells, without spending too much money?
Nathan
I tried some conductive ink, and that worked for connecting the negative traces on the surface of the cells, but conductive ink is expensive and my pen dried up after I drew the first line.
My latest attempt was to use some aluminum foil strips, taped to the surface of the cells. The tape doesn't affect the performance because it is transparent, and it holds the cells together (the panel is somewhat flexible; bonus). But the connection between the cells and the aluminum foil is crappy unless I apply pressure.
The surface of the cells is of course a silicon crystal; the texture is similar to the ceramic on old CPU's.
A quick search on wikipedia gave me these numbers:
Silicon melting point: 1414 C
Aluminum melting point: 661 C
Using a lighter to melt some of the aluminum foil strips, I found that it didn't ball up like solder does, I think my best option would be to melt (bond) the aluminum foil to the surface of the panels. As I type I have a small panel with aluminum foil in a small toaster oven, as close to the element as I could get it, with the temperature cranked to 220 C, but I don't think that will bond the foil to the silicon...
These cells are incredibly cheap because they are scrap cells, a 4"x4" panel would produce 1W of power in a nice sunny day, which translates to about 2W per $1 spent, not including the price of a roll of aluminum foil + picture frame.
Any ideas on how I can get the foil bonded to the surface of the silicon cells, without spending too much money?
Nathan