Use a spudger to carefully pry the battery connector up and disconnect it from the logic board.
Look at the pinout on the bottom of the battery connector circuit board. If there's no gap in the two rows of pins (if both rows contain ten pins), it's the Non-Energy Star version. If there is a gap (two rows of six pins each, separated from two rows of three pins each), then it's the Energy Star version. These two versions aren't interchangeable.