Yesterday I set out to make a new battery pack for my power tools (Makita, 10x18650). Had a bit of a problem with getting the cells into the plastic box, so I had to get them out of there and make some more room. They were stuck though, so I used a flat screw driver to pry them out… very carefully of course. Not carefully enough, apparently! Suddenly there was a whooshing sound (a battery venting I guess? there was a weird smell as well), so I grab the pack and run to the door, frantically trying to get out.
After the panic attack is over, I go out and grab the pack to find out which battery is screwed, so I can replace it. Weirdly enough, they all still measure 3.63V. I can’t really see anything that looks wrong either, except a couple of scuff marks. Since the ten batteries are glued together, testing them out is a bit of a bother, but I’ve now tried charging (not fully, just for 10-15 minutes) the batteries on a Turnigy Reaktor (basically an iCharger), and everything looks ok so far.
So, what really happened? Can a vented battery still measure the same voltage as before? Did I poke a hole in a battery, but can’t see it? Did I somehow short something out? I have spare batteries, but not ten of them, don’t want to change them all… 
For the last 24 hours I’ve designated everything that feels a bit off as proof of poisoned-by-being-stupid, but I can still see and most other bodily functions also work about as well as before the accident, so I’m probably ok. Maybe. Can one get super powers from sniffing whatever comes out of Lithium batteries when they vent?