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