Session: 09-02: Photovoltaic & Electrochemical Technologies

Paper Number: 131254

131254 - An Experimental Study on Performance Degradation and Recovery Protocols of Module Stack Proton Exchange Membrane Fuel Cell Under Dynamic Load 

Abstract: 

The Proton Exchange Membrane Fuel Cell (PEMFC) is a promising power source for commercial vehicles. However, reversible losses deriving from harsh operating conditions adversely affect the performance and lifespan of PEMFC, which reduces its competitiveness in the transportation market. Voltage cycling is one of the recovery approaches to retrieve the reversible loss caused by the catalyst surface oxidation. This solution proved beneficial to restoring PEMFC performance under the operating conditions of static and cyclic load on single-cell stacks. In addition, few studies have reported a restoration in PEMFC performance after a long period of not working. However, the long duration of shutdown might not be desirable as a recovery approach in the transportation field, where commercial vehicles are operated continuously.

In this study, the restoration performance of the voltage cycling and shutdown method was experimentally investigated and compared. A customized dynamic load profile, which was used as a test cycle, was developed based on the World Harmonized Vehicle Cycle. Various long-duration tests with different cell temperatures were conducted on 3-cell stacks. Each test was divided into periods having equal duration, in which the test cycle was repeatedly performed. The recovery step was carried out after each period. To analyze the performance degradation of periods and recovery effectiveness, polarization curves were measured at the beginning and end of each period, as well as after recovery steps.

Experimental results indicated that the performance degradation increased as the cell temperature rose. In general, the degradation became considerable over time. After the first 50-hour period, PEMFC performance decreased noticeably. It then declined dramatically in the following test periods. The medium and high current density zones in polarization curves experienced a higher performance drop than the low current density zone. Regarding recovery performance, the voltage cycling method was merely effective, whereas the shutdown method significantly retrieved reversible losses. The recovery efficiency of the shutdown method was maintained in the low-to-medium current density zones. However, its effectiveness deteriorated as the current density exceeded the maximum value.

Based on those outcomes, the cycling voltage method revealed its drawbacks in the performance recovery under the dynamic load condition of multi-cell PEMFC stacks. Although the shutdown method showed its effectiveness, it is still necessary to shorten the procedure and enhance the recovery efficiency at high current density. This study emphasized the potential of the shutdown method and also motivated other research to further develop it as a recovery procedure that satisfies the restoration requirements of fuel cell commercial vehicles.

Presenting Author: Quan Thien Phan Nghiem Chungnam National University

Presenting Author Biography: Master student at Chungnam National University

Authors:

Quan Thien Phan Nghiem Chungnam National University
Huu Linh Nguyen Chungnam National University
Younghyeon Kim Chungnam National University
Sangseok Yu Chungnam National University