Hello,
This is a tricky question because the battery case itself requires you to break into it and that is usually the end of it being usefully again as you need to slice through the rubber. If you are willing to do that anyway the charging port can be replaced as its a separate unit but you would have to search online on eBay and other websites to see if these parts are for sale.
I have linked the ifixit guide so you can have a look at how this can be done but if you are not comfortable in repairing these types of electronics I would stick with buying a new case.
[guide|53762]
Hopefully that helped