Experimental study of the steady-state and dynamic characteristics of 1 kW water-cooled PEMFC

Abstract

The Polymer Electrolyte Membrane Fuel Cell (PEMFC) has been widely developed in the shipping sector, prompting the need to accurately understand its characteristics under various operating conditions and load variations. This study presents an experimental investigation into the steady-state and dynamic characteristics of a 1 kW water-cooled PEMFC stack, aiming to optimize reactant consumption and to assess the PEMFC voltage response under varying load conditions. In the steady-state tests, experiments were conducted at three different stoichiometries of hydrogen and air to evaluate the effect of stoichiometry on PEMFC efficiency. The results showed that the electrical efficiency improved by 10% at lower hydrogen stoichiometry (1.2) compared to the manufacturer's recommended values (1.6). In the dynamic tests, the behaviors of undershoot voltage and open circuit voltage (OCV) were examined using load-step and load-ramp conditions. Results showed that the undershoot voltage could be reduced either by narrowing the load step size and ramp rate or by implementing a reactant supply strategy, which increasing the gas flow rates before increasing the current. A consistent 0.55 V recovery was observed at the OCV after 10 s, regardless of the step sizes or ramp rates of load, indicating that the PEMFC was in good state of health after dynamic load conditions. OCV can serve as an effective diagnostic tool for assessing PEMFC health.