Effect of Operating Conditions on Voltage Transient Response of High‐Temperature Proton Exchange Membrane Fuel Cell Under Load Changing

Abstract

The transient response of a high‐temperature proton exchange membrane fuel cell (HT‐PEMFC) is critical for control and optimization. The objective of this study is to investigate the effects of operating conditions and control parameters on the transient response of the HT‐PEMFC during load variations to optimize the operating conditions. The main causes of the voltage undershoot are investigated experimentally, and the effects of air stoichiometry, air humidity, operating temperature, and backpressure on the transient response of the HT‐PEMFC are evaluated in terms of internal resistance and voltage response. The results show that during load changes, the local gas starvation of the cell and the change in the hydration state of membrane‐electrode‐assembly may be the main cause of the voltage undershoot. The voltage drop is affected by the combination of ohmic resistance, charge transfer resistance, and mass transfer resistance. In addition, operating temperature and air stoichiometry can affect voltage drop and voltage undershoot during load changes. Proper humidification of the air can alleviate voltage undershoot problems. Increasing the backpressure can improve the transient performance of the cell, but does not alleviate the voltage undershoot problem. The study can provide guidelines for the design and control of HT‐PEMFC operating conditions.