An electrochemical battery can include electrodes (a cathode and an electrode) arranged on respective surfaces of an electrolyte. The electrodes and electrolyte can each be solid state films that can be layered on top of one another to create a stacked structure disposed on a substrate. A polymeric sealant material can be applied over and around the battery stack and a moisture barrier can be formed over the sealant material to thereby prevent moisture from reaching the battery. Conductive terminals electrically coupled to the cathode and anode, respectively, can be formed on a second side of the substrate. As such, the battery can be flip-chip mounted to corresponding mounting pads and thereby connected to other electronics that can receive power from the battery.