A method of manufacturing a micro-battery is provided. The method includes forming a micro-battery device by forming a first metal anode via and a first metal cathode via in a first substrate, forming a first metal layer on a bottom side of the first substrate, forming a first battery element on a top side of the substrate, forming an encapsulation layer around the first battery element, forming trenches through the encapsulation layer and the first substrate on different sides of the first battery element, and forming a metal sealing layer in the trenches to cover at least a plurality of sidewall surfaces of the first battery element. The metal sealing layer is electrically connected to the battery element through the first metal layer and the first metal cathode via.