The closest we've got nowadays is, IMO, 18650 cells - they're manufactured by a lot of different companies, and you can (usually) put them in anything that expects that size + capacity.
I think many of those power tool batteries are 18650 or 21700 batteries soldered together under the shell. Laptops used to be, but as they've gotten slimmer and more space-conscious, now have mostly moved to custom pouch designs.
They are not soldered. They are spot welded to bus bars. The distinction matters because the long duration of heat from a soldering iron will destroy Li-ion cells. A spot welder delivers more heat over a shorter time. This doesn't damage the cells.
Yep, someone should design a shell that you could 3d print and drop in 18650s to run power tools for Dewalt/Makita/etc. Connecting the batteries is kind of annoying but presumably there's some standard spring clips off the shelf that might work.
FWIW, power tools batterie are generally high amp rated and require a BMS that can support it. Not that you can't do it, but won't work with off the shelf 18650s.
I looked up teardowns of Dewalt, Milwaukee, and Makita battery packs and saw LG HB4, Samsung 30Q, and LG HD2 cells, respectively. Those are all off the shelf cells.
