For removing soldered-in batteries like this - I do it on synthesizers a lot - instead of risking heating it up too much just cut the legs off and pick them out individually.
Same for any multi-legged part with soldered-down mounting tabs like pots, chop 'em up and remove 'em a leg at a time. You'll put far less heat into the PCB, drastically reducing the risk of damaging the pads.
When you come to solder the new battery in, you'll have trouble getting the solder to stick. Get a blob of blutac, stick the battery to your bench, tin the legs very lightly, and let it cool for a few minutes while you clean up the pads on the board. Then solder it in while it's warm but not totally hot.
By doing it the slow and complicated way, you'll be done so much faster than if you tried it the quick and easy way.
ErroneousBosh · · focus · HN ↗
Same for any multi-legged part with soldered-down mounting tabs like pots, chop 'em up and remove 'em a leg at a time. You'll put far less heat into the PCB, drastically reducing the risk of damaging the pads.
When you come to solder the new battery in, you'll have trouble getting the solder to stick. Get a blob of blutac, stick the battery to your bench, tin the legs very lightly, and let it cool for a few minutes while you clean up the pads on the board. Then solder it in while it's warm but not totally hot.
By doing it the slow and complicated way, you'll be done so much faster than if you tried it the quick and easy way.