This is one of those photos that's deathly boring unless it's exactly what you are looking for, in which case it is quite interesting.
I wanted and was advised to have a protective case for my 36 volt 15 Amp hour battery from Cycle 9. The large Armored pocket from Granite Gear fits perfectly for this, with no room to spare. The product website has a photo of the other side of the bag, but nowhere online shows what this side looks like.
So, you can see there are some straps along this side that you could use strap the battery to a bike, and that wires can come out the end while keeping the waterproof zipper mostly closed.
Boring, but just want I needed, and difficult to find since it's not marketed as an e-bike battery case.
If you might it this far, you might also be in this related blog post about how I attach it to the bike.