Influence of Operational Parameters on Dynamic Load Capacity of PEM Fuel Cell System

Kurzfassung

The polymer electrolyte membrane fuel cells (PEMFCs) currently appear to be the preferred fuel cell due to their inherent virtues of being compact, quick start up, better efficiencies, and very low emissions. However, there are several issues related to fuel cost, durability and performance which impedes their commercialisation. The dynamic behaviour of the PEM Fuel Cell system is crucial for successful implementation in applications with rapidly varying power demands. For that purpose, experimental investigation was done to see the influence of operational parameters on dynamic load capacity of PEMFC under different operating conditions using a self developed PEM fuel cell test stand. One of the main objectives, control strategy for air compressor was developed with the help of feed forward PI control approach. The influence of operating parameters such as stoichiometry, cathode inlet pressure, oxygen composition on the transient of stack voltage were measured. Experimental results show that the dynamic behaviour of PEMFC during load steps was improved by increasing the cathode inlet pressure.The transient response of a PEMFC was measured for various cathode gas compositions. Results show that the PEMFC operated with the pure oxygen as a cathode supply, cell voltage response to current steps was quick, with response time of 0.02 s. Results of current jumps between oxygen composition of 35% at 1 bar absolute pressure and operating absolute pressure of 1.7 bar are comparable because of their same partial pressure of oxygen. The experimental results will be helpful for optimizing the control and operation strategies for PEM fuel cells.