This guide is useful when the battery is not holding charge or completely broken.
To remove the battery cover, first turn the phone so that the keypad is face down.
While holding the phone with one hand, place the thumb of the other hand at the top of the battery cover.
Slide the battery cover toward the bottom of the phone to remove.
To remove the battery, first grab it using a finger on either side.
Pull the battery upward, while securing the phone with your other hand.
Gently remove the battery and place it to the side of the phone.