Sparks from 18650 battery pack while dissembling

[108CAM]

I was taking apart a battery pack from a cordless vacuum so I could salvage the 18650 cells.
I had some sparking occur and now I'm scared that the battery will explode because one of the sparks happened on the bus bar that joins the chain of batteries to the circuit board. I need to know if the battery is in danger  of exploding without warning and how to cut the bus bars without using a soldering iron or creating more sparks. I also need to know what to do to make the battery safe

[Jwillis]

Sparks are not a big deal as long as you don't create a prolonged short where the battery heats up to a danger point . They need to get pretty hot for that to happen . If the battery is cold or only slightly warm your OK.
Removing batteries from a pack is pretty basic . You can desolder any wires connected or just cut them . There will be two main positive and negative wires , a few balance wires and possibly a temperature sensor wire  . In most packs , the batteries have been spot welded together with nickel plates . Depending on the voltage and amperage of the pack , the batteries will be in series and possibly parallel . Just cut separating each series then cut the parallel batteries into individual pieces . Then if you like just peel the remaining  nickel from the battery poles with pliers. There will be jagged spurs so just clip those away. Don't grind them or you may damage the battery .   

[amyk]

Some insulating tape is always a good idea  when disasembling battery packs, to keep the connections you cut from shorting to something else.

[digsys]

I've recently attempted to split apart some 36V 18650 packs used in power tools. Yep, it is dangerous, no matter the precautions you take. A few sparks, however, are not a problem (as noted before) .. BUT the nickel welded plate is NOT easy to remove, and I have all the fancy tools. In the end I gave up, as I could see the attempt doing physical damage to the cells. They did a damn good assembly of the 20x cells. Note: using a fine blade dremel to cut up the plates didn't look safe. Good luck.
I've had better luck with Tesla packs

[james_s]

It's pretty hard to make a 18650 cell explode, they typically have some sort of internal fuse that will fail and open the circuit if they get severely enough overloaded. You want to avoid sparks but it certainly won't explode. Most incidents with lithium ion cells occur while charging.