A battery assembly for a medical device, the battery assembly comprising a cathode (238) consisting of a single, solid, cylindrical elongate cathode comprising carbon monofluoride and silver vanadium oxide, the cathode having first and second ends； a current collector within the cathode； an anode (236) consisting of a single, tubular-shaped lithium metal anode； a separator (240) consisting of a single, tubular-shaped separator disposed between the anode and the cathode and having a closed end covering the second end of the cathode, the cathode, anode and separator being coaxial； an electrolyte； a cylindrical housing assembly electrically coupled to the anode and encapsulating the cathode, the anode, the separator and the electrolyte； and a feedthrough pin (260) exposed from and electrically insulated from the housing assembly, the cathode being electrically coupled to the feedthrough pin through the current collector within the cathode.
