The wires pass through a hole in the battery cage, which is also glued to hold them in place. The easiest way to remove the battery wires from the hole is to just cut them. Cut them one by one to avoid shorting the battery.

To remove the battery from the cage, unscrew the two screws holding it in place. Since the wires are glued, use a hairdryer to soften the adhesive and gently pull the cable out.