I'm gonna get yelled at, but I would not solder a battery.
Can be done with practice.

I remember successfully doing it once or twice before. But you're right --
it's not a good idea. Solder doesn't bond well with most battery cases, and
the case is huge heat sink that makes it hard to make a quick solder joint.


Trying it for the first time on the only
battery you have is fraught with risk.

Charlie Fraught and Joe Risk?


Last resort is to drag it down to Batteries Plus or some similar
vendor that has the proper spot welder.

I lucked out. The guy at the local B+ store said he'd do it for free if I
came in early tomorrow morning.