Study of the characteristics of temperature rise and coolant flow rate control during malfunction of PEM fuel cells

• Published in: International journal of hydrogen energy Vol. 46; no. 19; pp. 11160 - 11175
• Main Authors: Chinannai, Muhammad Faizan, Lee, Jaeseung, Ju, Hyunchul
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 16.03.2021
• Subjects: BOP components; Coolant flow rate; Fuel cell modeling; Malfunction analysis; PEM fuel cell; BOP components; Coolant flow rate; Fuel cell modeling; Malfunction analysis; PEM fuel cell
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2020.04.221

In actual PEM fuel cell systems, the coolant flow rate is generally controlled to maintain a preset temperature at the coolant outlet. This implies that a change in coolant supply flow rate is a good early indicator of a malfunctioning PEM fuel cell stack and system components. In this study, various fuel cell malfunctions are simulated based on the practical coolant flow control strategy by using a three-dimensional, two-phase, multiscale PEM fuel cell model developed in our previous studies. The focus is on analysis of the characteristics of coolant flow rate change along with voltage degradation in various fuel cell malfunction cases. The model predictions show that in general, the coolant flow rate tends to increase proportionally with the degree of voltage degradation, but the increase in temperature inside the membrane electrode assembly (MEA) is not always related to the voltage drop and is influenced more directly by local current density distribution. Although the present numerical comparison between the normal and malfunctioning cases is conducted at the low current density of 0.3 A cm−2, the general cell behavior will not be altered at higher current densities due to inverse relationship between cell performance and waste heat generation. The present work elucidates the complex interplay among increase in coolant flow rate, increase in MEA temperature, voltage drop, and change in local current density distribution when a PEM fuel cell malfunctions. •The fuel cell model was applied to the cell geometry with coolant channels.•The change in the coolant flow rate is a good indicator of fuel cell malfunctions.•Cell temperature rise is not always proportional to the level of voltage degradation.•The cell temperature rise is mainly affected by current density distribution.