Depends on how it's bent, I suppose. You could try using a pair of pliers to pull or push it back into place, otherwise you might have luck taking off the back of the shell to get access to the battery terminals directly.
One of the sides is just a sheet of metal wedged into the back shell, you should be able to pull that one out without taking the system apart and straighten things up as needed. The other side is soldered onto the board and you don't want to pull on that too hard.
Left side from the back is soldered to the board, right side you can just pull out with pliers and push it back in afterwards.