Locate the small flex cable covering the battery terminal

Take a pair of tweezers in one hand and pull up on the plastic flap

Take the hook end of a Halberd Spudger in the other hand and gently pry up the retaining flap on the battery cable ZIF socket

Be sure you are prying up on the hinged retaining flap, not the socket itself.

Make sure to use gentle force as this shouldn't require a lot of force. If excessive force is used, you could break the flex cable.