[chbot] Battery Pack - the 27 chocolate fish challenge

[kerry at manukadesign.co.nz]

Could you not just bypass the two dead cells and leave the in place?

Kerry

Quoting Mark Atherton <markaren1 at xtra.co.nz>:

> Hi All,
>
> Last night Paul L was kind enough to give me a busted battery pack
> from an electric drill - www.idesignz.org/BP/battery_pack.jpg.
>
> The pack contains 10 x
> <http://www.idesignz.org/BP/DM_IMR18650E.pdf>http://www.idesignz.org/BP/DM_IMR18650E.pdf
> Lithium Ion cells.
>
> Two cells are busted, hence the reason for the unit being thrown out,
> and of course they are in the middle.
>
> The cells are capable of 20A discharge each, and two cells are in
> parallel. Short circuit current is likely in the order of 100A per
> cell given internal resistance of 35m ohms and 3.7V terminal voltage.
>
> The connecting tabs are copper sheet that have been sport welded onto
> the end of the cells.
>
> There is a black plastic saddle that the cells are attached (glued
> ?), with about 0.5mm clearance between cells. Max working temp is 65C.
>
> So the puzzle of the day is how to disassemble the pack safely.
>
> My inclination is to start by cutting vertically with an abrasive
> non-metallic dremel disk - at least the neighbours will be isolated then.
>
> Might then be tempted to soak in white spirit to dissolve the
> adhesive to the black saddle, but that may do nasty things to the
> green cell insulation.
>
> If you short adjacent cells you **will* start a very nasty fire.
>
> Any other thoughts ?
>
> -Mark
>
>
> _______________________________________________
> Chchrobotics mailing list Chchrobotics at lists.linuxnut.co.nz
> http://lists.ourshack.com/mailman/listinfo/chchrobotics
> Mail Archives: http://lists.ourshack.com/pipermail/chchrobotics/
> Web site: http://kiwibots.org
> Meetings 3rd Monday each month at Tait Radio Communications, 175  
> Roydvale Ave, 6.30pm
>
> When replying, please edit your Subject line to reflect new content.
>