GamerCore
Android Enthusiast
While the regular Moto G5 (aka Moto G 5th Gen.) has a removable battery cover on the back, the G5 Plus is a different story.
The back cover cannot be opened -- at least not my normal means -- so please do not try prying it off. Of course it's possible to remove the back cover for repairs, but you'll need some specialized tools to get this done and run the risk damaging the phone and/or battery.
In other words, avoid doing this unless absolutely necessary.