You may need to replace the battery in your Samsung Solstice for a number of reasons. Perhaps the battery is damaged, or perhaps the phone is frozen and you need to remove the battery to reset it.
Gently slide the cover off of the phone by pushing it upwards, in the direction of the small arrow on the back cover.
Set the cover off to the side once you have removed it.
Wedge a plastic opening tool in between the rear end of the battery and the plastic frame.
Pry the battery up out of its recess and away from the phone.