They placed it there for balance and if it where to blow up, it is more protected from you. Actually real easy to get to, just take off the tire and remove the access panel, they say you can turn the tire but that is a tight squeeze
I wish they would have put the battery in the trunk like the Chargers. I got to it by just lifting it then turning the tire but it was just to connect wires not remove it. Another way to encourage dealer work.