Use a pair of tweezers to lift up the black adhesive pull tab on the side of the battery, enough so you can grab it with your fingers.

Grab the adhesive strip pull tab and slowly and carefully pull the adhesive strip out from under the battery.

Keep the angle of the adhesive strip as parallel to the laptop as you can. Try to avoid dragging it across the inside of the case.

If the adhesive strip breaks, leave it in and proceed to the next step.