Rechargeable battery pack and battery pack charger with safety mechanisms

摘要

Rechargeable battery packs include one or more key slots along a rear edge in order to distinguish it from other battery pack types and rectangular guide tabs to be backward compatible with former battery pack chargers and former battery operated devices. Battery pack chargers include one or more key tabs in a door and rectangular guide tabs to differentiate rechargeable battery packs that can be safely charged. Door closure switches on a safety switch to activate safe charging of a rechargeable battery pack with matching one or more key slots. The one or more key tabs and the one or more key slots provide a safety mechanism to distinguish rechargeable battery packs which can be safely charged. Rectangular guide tabs on sidewalls of an inner housing allow rectangular guide tabs of the rechargeable battery packs to slide under and further differentiates those that can be safely charged.