Removing the battery cover on your Canon 7D camera is one step to getting twice as much battery power to your camera. By taking off this little piece of plastic, you have the ability to install a battery grip, capable of holding two batteries and doubling your run time. But you can't install the battery grip without first removing the battery cover. Fortunately, Canon made removing the battery cover fairly easy, and it takes a short amount of time to take it off of the 7D's body.
Turn over your 7D in your hand to reveal the underside of the camera, orienting the lens away from your body. The battery door is on the left side of the body.
Open the battery door using your thumbnail. Push on the gray button on the top of the battery to release the battery from the camera. Lift the battery out of the camera with your hand.
Locate the black square clip at the hinge of the battery cover on the 7D. Push the clip towards the back of the camera, then twist the battery cover slightly and pull it out from the camera.