This battery lasts the life of the router under the operating environmental conditions specified for the router, and is not field-replaceable.
But who determines its lifespan?
Knowing there is a battery set to fail and I can't simply replace it makes me physically uncomfortable. Enough so that I'd rather it not have RTC.
Thanks Cisco.
I've found the little flush cutters that came with my Ender3s are awesome for removing stuff that's been spot-welded like this. I took apart a few cordless tool packs with them, and kept everything so neat I could easily reuse all the tabs if I wanted.
Just wait until you get your hands on some quality flush cutters. (Knipex is an example or even Weller sometimes.)
Keep using cheap ones for general purpose use, but a good set of flush cutters is worth its weight in gold when you actually need dozens of actual flush cuts.
Have you have ever seen the Rick and Morty episode where Morty experiences true level? Yeah. It's like that.