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Apr 14, 2014, 10:12 PM
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Lipo teardown 2





Tore down a completely puffed, dead, 0V cell. It was still air tight.





So basically, it's a stack of copper anodes (-) & aluminum cathodes (+) separated by plastic. They're soaked in a fluid. The plastic conducts positive lithium protons between the terminals, but not electrons. The plastic is why they're called polymer batteries.

The copper sheets (-) are coated in lithium + graphite. The aluminum sheets (+) are coated in lithium + cobalt. The positive lithium protons transfer through the polymer from the - to the + electrodes. The negative electrons transfer through the load from the - to the + electrodes.





Neither the anodes or cathodes reacted violently, even in water. Despite not being air tight, the electrodes stayed completely black when wrapped up. Then some of the anode turned white when completely unwrapped. Since it was completely discharged, it would have been residual lithium. The cathode side didn't change color.




They're all connected in a parallel fan at the electrode.

Last edited by Jack Crossfire; Apr 14, 2014 at 10:21 PM.
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Apr 14, 2014, 11:03 PM
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slebetman's Avatar
Thanks for this teardown! Very cool. Didn't realize that Lipos are actually Cu-Al. So the Lithium's just the electrolyte?
Apr 15, 2014, 01:32 AM
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Artful Owl's Avatar
I pulled apart a 2 cell lipo I needed to make 2 single cell. A problem arose when I tried to solder to the positive and negative tabs. The solder would not stick. Is this because the tads are aluminum?
Apr 15, 2014, 07:00 PM
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They're tinned with lead free solder. It requires a 700F soldering iron.


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