I previously downloaded a ready part here from Thingiverse, but that was completely different from my model.
So I designed this one and printed. It took some effort as the battery door is full of tiny edges, but this one works.
I added to the original par thicker battery separators, mainly to give more material to the part, and I have made also the outer shell thicker to avoid to print a 0.5 mm layer.
This way the door stands off a bit, but is more robust. You can always slice the outer part down if you like it thinner. This doesn't affect part's matching.
I suggest to print it @ 0.1mm layer to have better accuracy.