Look for heated motorcycle glove liners.
I had some years ago - the wiring is a fine mesh around the hand/fingers, usually on the outside of the glove material (or sandwiched between layers).
The mesh stops mid-finger, so you could just cut the tips off, or maybe they make them without tips today
As for your battery concern - so long as the battery matches the voltage requirement, it's then just a matter of making the connector match, which is trivial.