Dell UG679 Lithium Battery Teardown

The battery pack on my ancient Dell E1405 laptop finally died, so I tore it apart to see what horrors might lurk within:

Dell UG679 Lithium Battery - teardown
Dell UG679 Lithium Battery – teardown

The case snaps apart without too much effort, although the delicate single-use latches won’t survive the operation. These certainly didn’t, which didn’t bother me at all, as I already had a replacement battery on order.

One of the cells (in the front) seems to have leaked ever so slightly inside its wrapper:

Dell UG679 Lithium Battery - leaky cell
Dell UG679 Lithium Battery – leaky cell

The three cells in that 3P section seem to have failed open: they pass no current at all.

The other pair of 3P slices, charged at 4.2 V with a 700 mA current limit until the current dropped under 10 mA, still have some life:

Dell UG679 3P sections
Dell UG679 3P sections

Perhaps recycling individual cells into LED glowies would be nice, as they have enough capacity remaining to run an Arduino for quite a while, and a 1S USB charger would make for a self-contained package.

2 thoughts on “Dell UG679 Lithium Battery Teardown

  1. What looks like liquid under the wrapper is often just goo they use to stick the cells together. Maybe not in your case, but I see it often enough in my cell harvesting sessions. Cells look a lot more legit then what pops out of packs in my corner of the world – usually from genuine HP packs as I get that crap at work for free.

    Also, case is usually epoxied or welded. I’ve never seen one with even a hint of serviceability – how old is that thing anyway?

    1. None of the other cells have anything suspicious under their wrappers, but ya never know.

      It’s gradually become the oldest laptop in my collection and it wasn’t new when I got it from Dell’s off-lease outlet. Maybe 2005-ish? Things have definitely changed since then!

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