A design of CPV and bipolar assemblies of nickel/hydrogen cell stacks (summary only)

A conceptual design of a Common Pressure Vessel (CPV) assembly of nickel/hydrogen cell stacks is described. The design features two 85 Ah cell stacks, giving a capacity of 210 Wh in a cylindrical composite vessel. The design is estimated to yield a gravimetric energy density of 71 Wh/kg and a volumetric energy density of 85.5 Wh/l (60 bar), although the significance of the latter figure is qualified. The preference for the two-stack module is largely influenced by the flexibility it allows for battery assembly. A study of bipolar assemblies identified interesting concepts, but no single preference. Simulations of the thermal performance of both designs for GEO and LEO cycles, against a number of idealized boundary conditions, indicate that the desired operating temperature range is maintainable with adequate boundary temperature control.