li-on battery terminal welding.
My power tool ecosystem is 18v Porter Cable, long obsolete. Battery pack replacements are getting crappier & crappier. Over the last couple of years, well-rated nickel tab spot-welding machine has come down from $250 to $130 ...about what I spend every 2 years on crappy battery packs. Worth a try so I can use quality 18650 batteries and rebuild.