A new structure for a pressurized metal-gas battery is presented, with emphasis upon reducing weight and volume. Thus, the battery is particularly suitable for spacecraft applications. Positive and negative terminals are moved away from the center axis of the terminating ellipsoidal domes of a cylindrically shaped pressure vessel, thus permitting smaller size and saving weight while providing torsional support to the electrode stack. A center rod and end plates are fabricated of an insulative, chemically resistant material having a high strength-to-weight ratio, and provide both axial and radial support for the electrode stack while permitting expansion and contraction of the pressure vessel independently of the stack. A weld ring for joining together two sections of the pressure vessel is placed in the center of the cylindrical portion of the battery, is freed from any requirement to provide mechanical support for the electrode stack, and advantageously permits the fabrication of the pressure vessel as two essentially identical halves.