Response of PEM fuel cells to a step-change in load is investigated experimentally in this work. Voltage undershoot, a characteristic feature of such transient response, is shown to be due to transients of water distribution in membrane phase occurring at sub-second time scales. Use of humidified reactants as a means to control magnitude of voltage undershoot has been demonstrated. Constant stoichiometry operation under certain current-step conditions is found to result in reactant starvation, potentially leading to cell shut down. Further, response under step decrease in current density has been explored to determine existence of hysteresis. Under sufficiently humidified conditions, response under forward and reverse step changes are found to be symmetric, but under low RH conditions, voltage undershoot is found to be twice as large as the overshoot. © The Electrochemical Society.
|Original language||English (US)|
|Title of host publication||ECS Transactions|
|Publisher||The Electrochemical Society|
|Number of pages||12|
|State||Published - 2008|
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: Funding for this work from ECEC industrial sponsor is gratefully acknowledged. The firstauthor is pleased to acknowledge King Abdullah University of Science and Technology,Saudi Arabia for travel grants to attend this ECS Meeting.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.