Here’s some interesting work shared by [Ben Kromhout] and [Lukas Lambrichts] on making flexible ... into a giant kerf bend – they got interested in whether one could 3D print such a thing ...

Sure, you can 3D-print adapters and jigs to accommodate the different batteries, or you can cheat a bit and put the charger and tester circuit on a flexible ... the board from bending too sharply ...