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Soldering to tabs on 18650 recycled

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    Soldering to tabs on 18650 recycled


    My apologies if this has been asked before, couldn't find anything on it.

    I'm processing 18650s from laptop batteries. The thought occurred to me to cut the nickel strips joining the batteries, rather than pulling them off, which would leave 6 or 8 mm at least of loose tab on each cell, then to tin this loose flap of nickel and form series connections with solid 1mm ish copper wire from tab to tab. I've made some blocks like this and it's pretty quick. The battery terminals seem to undergo minimal heating, contact with the iron being in the order of 2 seconds to tin and similar to attach wire. It would also allow for cells to be removed from large blocks as necessary. Also it makes dismantling a lot quicker.

    Any thoughts on this? The one downside I can see is that it's fairly unsightly. As to temperature, the heat dissipated into the battery must surely be less than with a spot weld I would think..?

    Any advice would be much appreciated!

    All the cell companies recommend not soldering to cells, and given that even heat from spot welding is not great for a cell I can't imagine soldering to cut tabs would be desirable.

    Then again, it is recycled used batteries so you are probably already prepared for less than ideal performance.

    Unfortunately you would have to use it for years before drawing firm conclusion on any potential to have worse long term cycle life and voltage sag, and that conclusion would probably not be even a useful anecdote unless the cells in the test pack were new. Cool idea but not easy to do a good test.



      Thanks for your reply, I suppose the crux is just how hot the cell terminals get, as you say. I really like the fact that you can remove cells easily though, seems invaluable to me, especially with used ones.



        Doctor Bass was doing this about seven years ago with good results. Its a little ugly but it works.