It looks to me like GB31241-2014 is a standard for battery safety requirements, so I see lots of different packs and form factors that meet GB31241-2014. The phone batteries I see all have side contacts, not the 3 wire connector. If it was clear what the 4 side contacts were besides +/-, and you had a correct sensor contact, I could solder the wires to it, if the pack fit the space. I only got a couple of dead-end hits for the OEM model number CP-1S1P-3950JM.
I'd prefer not to have to buy one battery from China, nor do I want to buy the spec for $140-420.