A method of fabricating a thin film battery may comprise: depositing a first stack of blanket layers on a substrate, the first stack comprising a cathode current collector, a cathode, an electrolyte, an anode and an anode current collector; laser die patterning the first stack to form one or more second stacks, each second stack forming the core of a separate thin film battery; blanket depositing an encapsulation layer over the one or more second stacks; laser patterning the encapsulation layer to open up contact areas to the anode current collectors on each of the one or more second stacks; blanket depositing a metal pad layer over the encapsulation layer and the contact areas; and laser patterning the metal pad layer to electrically isolate the anode current collectors of each of the one or more thin film batteries. For electrically non-conductive substrates, cathode contact areas are opened-up through the substrate.