There is disclosed herein a rechargeable battery pack for use with electronic devices, such as electronic flash units used in photography, and wherein the battery pack has a pair of exposed electrical terminals. At least one of the terminals is constructed in the form of a switch such that when the battery...http://www.google.es/patents/US4563627?utm_source=gb-gplus-sharePatente US4563627 - Switching system for high voltage battery pack
