SYSTEMS THAT COMPRISE POWER TOOLS AND ENERGY SUPPLY DEVICES, AND ENERGY SUPPLY DEVICE

A system including a power tool and a first and a second energy supply device, wherein the energy supply devices can be detachably connected to the power tool via an interface. The first energy supply device has a number a of at least two contact partners for transmitting electrical energy to the power tool, whilst the second energy supply device has a number b of at least two contact partners for transmitting electrical energy to the power tool, wherein the number a of contact partners of the first energy supply device differs from the number b of contact partners of the second energy supply device. A system in which the contact partners of the energy supply devices have different coatings.