Soldering leads on laptop cells

Discussion in 'General Electronics Chat' started by Lectraplayer, Apr 3, 2015.

  1. Lectraplayer

    Thread Starter Member

    Jan 2, 2015
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    5
    What are ths main considerations for durably soldering leads onto a lithium ion laptop cell? I know this can creats a pyrotechnic acid bomb if you get the cell too hot, and lithion ion can be about like napalm. While a battery holder would be best, the 4/3 A size I see quoted as a laptop cell is hard to find locally sourced, and I don't want to order an item I intend to use commonly.

    Note: Do not solder directly to any battery cell unless you know what you are doing! Batterys can, and sometimes do explode, and the results are often horrid.
     
  2. Papabravo

    Expert

    Feb 24, 2006
    10,166
    1,797
    There is no way to make this operation safe.
    Is your life worth nothing to you?
     
  3. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    They are not soldered, they are typically welded with a very hot, small and, therefore, short contact time that does not heat the contained lithium much.
     
  4. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
    2,803
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    Well, actually, a pyrotechnic alkali bomb, but nobody's keeping score:D

    With officious regards
    HP
     
  5. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    5,699
    907
    If you are motivated and have several packs to do, you can build your own tab welder. I built one based on the description in this link: http://www.philpem.me.uk/elec/welder/

    Here's a example of a 2S pack of RCR123A LiFeP rechargeable that I made this morning:

    upload_2015-4-3_11-2-20.png

    The little teflon washer is something I have been adding since NiCd days. It is intended to protect against any short between the nickel strap and battery case. In this example, I used 1/8" nickel straps, 0.005" thick.

    John
     
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