Battery Spheres are a form of energy for Wasteland that appear in Epic Mickey 2: The Power of Two, replacing the Power Sparks from the first game. These were built by the Mad Doctor himself. They are necessary to power the train in the Disney Gulch. Whilst not all 3 are required to continue, you will be presented with a pin for doing so.
They are also in some areas of the Dahl Engineering Corridors, where they must be placed on the appropriate charger in order to power up certain objects which in turn allows the player to continue on their path.