After getting your hands on the worker uniform and sneaking past all of the robots in the factory, you will find yourself in a room that has a glass tube in the middle with green electrical bolts shooting around. This is the giga battery that you came for
Look around the floor of this room and you will see there are three red squares on the floor with red lights around them. When you stand on the platforms, they will turn green. You will need to press down all three of these at once in order to unlock the giga battery so that you can take it and move on with your business.
You will need to activate the first robot in the room. This looks a bit like a filing cabinet. You can walk over to it and activate it. Once it is activated, it will follow you around the room.
Make it follow you over to the chain wire fence nearby and turn it off when it is next to the fence. Climb on top of it and it will allow you to climb over the metal wire fence. Inside you will find another of these robots. Unlock the gate and activate the robot.
Place one robot on each of the squares on the floor. The third square will need the drum/battel to be rolled over to activate it. Once all three pressure plates are down, you will be able to take the battery