US Patent 10297878 Vacuum cleaner and a battery pack therefor

A battery pack suitable for a handheld appliance, the battery pack including a plurality of cells and a circuit board associated with the cells, wherein the plurality of cells and the circuit board are contained within a housing, wherein the housing is defined by first and second separable housing sections which are engagable with one another to form a complete housing, wherein the circuit board includes an illuminable element that the circuit board is configured to illuminate to indicate the status of the battery pack, wherein the illuminable element forms part of the external surface of the battery pack and is located intermediate the first and second housing parts.