Battery pack with axially extending and rotatable electrical connections and catch

A battery pack may supply power to a device such as a PDA, a hand-held scanner, or a laptop computer, when inserted and rotatably locked therein. The battery pack is adapted to maintain electrical connectivity with the device, once unlocked, during counter-rotation and before removal. Electrical connectivity is provided by discrete electrical contact pads on the battery pack, each of which may form various annular shapes at different radii. The electrical contact pads are detected by spring-loaded pogo pins on the device. Electrical connectivity is maintained for a battery detect pin for only approximately fifteen degrees of counter-rotation, where its disengagement warns of impending power loss, and triggers a proper shut-down sequence to save data. One contact pad is electrically coupled to a negative terminal within the battery pack, and another is electrically coupled to a positive terminal. The battery pack houses one or more rechargeable batteries, preferably lithium-ion.