Connecting A123 20ah lithium prismatic cells

Discussion in 'Prius PHEV Plug-In Modifications' started by ericbecky, Jun 19, 2012.

  1. chenyj

    chenyj Member

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    Here is Real Force tab connection approach. We have some tab connector sets available. It is $50 for 10 sets. Each set includes three screws/washers/lock washers, one flat piece steel bracket and one flat piece steel bracket with three welded nuts.
     

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  2. ericbecky

    ericbecky Hybrid Battery Hero

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    On the Electric Miata blog there is a post showing his fabrication of an a123 pack.

    Although he has several cells in parallel, it is still worth a look.
    Electric Miata: Summary of A123 module design

    Basically a bolt/washer/nut fastening setup.
     
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  3. NortTexSalv04Prius

    NortTexSalv04Prius Active Member

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  4. Andy Haard

    Andy Haard Junior Member

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    This is basically how I plan to do it:


    The green parts are isolators in Epoxy G10/FR4, same material as circuit boards are made of.
    Depending on if you want to connect cells in serial or parallel you'd want the isolators in different thickness.
    I'm doing 4 packs of 38 cells in series in each pack, then connecting 2 packs in series with the other two in parallel.
    Each pack will have 19 cells opposing each other, tabs pressed together with 3mm thick isolators. Steel plates at top and bottom of isolators and 3 M8 bolts through.
    Connections between pack could be done as shown in the film or as in attached PDF, a copper bar of same thickness as isolators, a nylon spacer for the M8 bolt, and the cu bar directly into the side of the next pack.
    This is NOT yet tested, only theories...
    One way of creating even better connections could be to use sharp screws through each isolator, sticking out a mm or two. like this:

    But it's not that easily done for thin isolators and it would make it a bit difficult to replace a cell.
    Connecting each cell junction to a BMS, will probably have to be done with a thin cu plate sticking out just enugh to solder a wire to it.
    Any thoughts on this would be much appreciated :)
     

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