This thread may be old but it still come up in relevant Google searches so I thought I'd contribute a bit of my experience with the OP's original question.
I have had the battery tab spot welds sheer clean off an internal battery by putting a game cartridge in the freezer (trying to freeze sticker adhesive to make it brittle). It was Ken Griffey Junior's Major League Baseball for Super Nintendo Entertainment System, but I was unable to intentionally duplicate the originally-unintended result when I tried to deliberately do that with a couple original copies of Pokemon Red on original Game Boy (had two different tabbed batteries but we're not bootlegs). Probably a lot of factors in play here, like how fast the temperature drops, how dissimilar the temperature gets between the tabs and the cell, and how spaced apart the spot welds are (Game Boy batteries are smaller).
Anyway, I never wanted to waste my cold-in-a-can on that curiosity because SNES cartridges are big enough to mount a battery holder and tabbed batteries for Game Boy games are easily available. I do wonder if a quick squirt would pop the tab right off or if getting it nice and warm before touching the spot welds to dry ice might work more consistently.
For those who don't know, Tennokoe Bank is a PC Engine "HuCard," which is a credit-card sized game cartridge format for a Japanese videogame console. In order to accommodate the battery it is already thicker than a standard HuCard so there is no room for a holder and VERY little room for improvisation without just abandoning the idea of stealthily closing it back up.
I like the copper tape idea but I have to wonder if there will be increased resistance. These batteries originally lasted decades (heck, many STILL work) so even a slight change could cut that life back significantly. This device is intended to backup game saves from a console that only temporarily retains them using a capacitor. Yes, a non-removable battery that can't even be recharged was the longer-term/more-permanent way to store the game save files.
It's also the only way to transfer saves between consoles so it's basically an early battery-backed SRAM memory card. Too bad HuCard format didn't use PCMCIA like Neo Geo memory cards from the same era.
Now that I've said all that, I'd like to point out that there are a lot of cool DIY videos and projects out there for making your own spot welder specifically for the purpose of building custom battery packs from lithium cells and nickel strips. You could use the same concept to add tabs to any CR2320 battery... or re-attach them if they can be consistently removed with cold as I suspect they might.