Design of a Versatile Regenerative Fuel Cell System for Multi-Kilowatt Applications

Abstract

Future missions to the Moon and Mars require a robust power source capable of providing several kilowatts of electrical power in support of exploration activities. By designing power supplies in multiple sizes, the units can be connected to obtain the required power output level. Fuel cell stacks are well suited for this type of configuration and each stack will operate at the same bus voltage to facilitate the interface. The fuel cells will use hydrogen and oxygen as the reactants and utilize the non-flow-through proton exchange membrane design. In operation, the fuel cell stacks will be connected to the reactant storage tanks though a common feed system. The fuel cells can be combined with an electrolyzer to form a regenerative fuel cell system. Proton exchange membrane electrolyzers have been sized to support the fuel cells and they will be interfaced through the same feed system. Since electrolyzers require an external power source, the electrolyzer will be operated at lower flow rates than the fuel cell. This type of power supply system has many applications. As part of an exploration strategy, the modules can supply electricity for a manned mission to the lunar surface. The modular design enables additional power supply units to be added to the infrastructure without requiring significant changes to the distribution network. In the case of long-term operations, aging power supply modules can be repaired or replaced without disruption to the network.