Abstract: A removable battery package incorporating electronic functions and a method to assemble said battery package is achieved. The battery package comprises one or more rigid or flexible battery cells of various shape and a smart card being wrapped around said battery cells to form an inside housing of the battery package casing. Said smart card could have customised dimensions to suit the battery cell and battery pack dimensions and could have the external connections on one side or on both sides. A cold welding process is possible to provide the connections from the battery tabs to said smart card.