Where to order Batteri connector

Even if those are possible to find, buy and solder to mobo, it would be a such time-consuming task no one will try to do that. Either find a donor board (that gives you the biggest chances to get that part) or ask someone to hardwire a new battery (since connectors are made of plastic, they are easy to screw up with soldering iron, which is why the chance to find someone able and wishful to do that is pretty low…