Experimental Investigation of Integrated Power System of Dead-End PEMFC H2/O2 Stack with Large Active Area and Internal Humidifier

Proton exchange membrane fuel cells with a dead-ended anode and cathode can obtain high hydrogen and oxygen utilization by a comparatively simple system. Accumulation of the water in the anode and cathode channels can lead to a local fuel starvation, which degrades the performance and durability of PEMFCs. In this paper for the first time, a new design for a PEM fuel-cell stack is presented that can achieve higher fuel utilization without using hydrogen and oxygen recirculation devices such as hydrogen pumps or ejectors, which consume parasitic power and require additional control schemes. Unified humidifier is another novelty that is applied for the first time. All part of systems is compact in a module. The basic concept of the design is to divide the anodic cells of a stack into two blocks by conducting the outlet gas of each stage to a separator and reentering to next stage, thereby constructing a multistage anode and cathode. In this design, a higher gaseous flow rate is maintained at the outlet of the cells, even under dead-end conditions, and this results in a reduction of purge-gas emissions by hindering the accumulation of liquid water in the cells. The result shows that with this new design the dead-end mode condition has the same performance as open-end mode. The all performance tests were carried out at an integrated power system.