Nasty experience disassembling laptop battery pack

[David18]

My nine cell (3S3P) laptop battery pack died so I decided to dissasemble it. I removed two cells and then went away to do something else. Returning a bit later I noticed that two cells were extremely hot and so I picked up the pack and ran to take it outside. Had it been left much longer it may have caught fire. Even though I took great care removing the cells I can only conclude that a short developed.

I suggest that if you decide to disassemble a pack, do not start and leave it but follow through and disassemble it completely.

Note on replacement: When looking for a replacement I decided to get a genuine OEM pack and not a clone from eBay even though it cost much less. These packs contain too much energy to take any risks with and I am not sure the clones would have all the protection circutry they are meant to have.

Regards,

David

 

[andrewnewman]

David. You were lucky. When disassembling a battery pack, you have to we extroadinarily careful removing the strips of metal that provide contact on the positive terminals of the battery. A classic error is to try and squeeze a cutting device between the batteries to cut the strap and gouge the shrink wrap below the positive terminal. Now either the cutting tool (scissors etc...) or the sharp end of the recently cut tab can short the battery. *ALWAYS* cut the negative terminal strap first so that you can pull the batteries apart before cutting the positive strap. When removing the strap remnants, be sure to either trip or fold the bits of metal so a sharp edge can't get levered between the poistive terminal and the side casing and cut through the shrink wrap causing a short (again).

Oh yeah... probably best as you noted to do all of the work in one session and then apply clear nail polish to the spots on the shrink wrap that got gouged or rubbed away. Not a bad idea to take a dremel tool to the ends either to clear off any solder debris that will scratch the contacts on your expensive flashlights.