In situ observation of deformation behavior of membrane electrode assembly under humidity cycles

Yusuke Kai, Yuki Kitayama, Masaki Omiya, Tomoaki Uchiyama, Hideyuki Kumei

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

The mechanical reliability of the membrane electrode assembly (MEA) in polymer electrolyte fuel cells (PEFCs) is a major concern with respect to fuel cell vehicles. When PEFCs generate power, water is generated. The proton exchange membrane (PEM) swells in wet conditions and shrinks in dry conditions. These cyclic conditions induce mechanical stress in the MEA, and cracks are formed. Failure of the MEA can result in leaking of fuel gases and reduced output power. Therefore, it is necessary to determine the mechanical reliability of the MEA under various mechanical and environmental conditions. The purpose of the present paper is to observe the deformation behavior of the MEA under humidity cycles. We have developed a device in which the constrained condition of the GDL is modeled by carbon bars of 100 to 500μm in diameter. The carbon bars are placed side by side and are pressed against the MEA. The device was placed in a temperature and humidity controlled chamber, and humidity cycles were applied to the specimen. During the tests, cross sections of the specimen were observed by microscope, and the strain was calculated based on the curvature of the specimen. The temperature in the test chamber was varied from 25 to 80°C, and the relative humidity was varied from 50 to 100%RH, and the wet condition was also investigated. The results revealed that the MEA deformed significantly by swelling and residual deformation was observed under the dry condition, even for one humidity cycle. The crack formation criteria for one humidity cycle corresponded approximately with those of the static tensile tests. The results of the humidity cycle tests followed Coffin-Manson law, and the number of cycles until crack formation corresponded approximately with the results of the mechanical fatigue tests. These results will be valuable in the critical design of durable PEFCs.

Original languageEnglish
Article number051006
JournalJournal of Fuel Cell Science and Technology
Volume11
Issue number5
DOIs
Publication statusPublished - 2014

Fingerprint

Atmospheric humidity
Membranes
Electrodes
Fuel cells
Electrolytes
Polymers
Crack initiation
Carbon
Water power
Gas fuels
Swelling
Protons
Ion exchange
Microscopes
Fatigue of materials
Cracks
Temperature

ASJC Scopus subject areas

  • Mechanical Engineering
  • Mechanics of Materials
  • Renewable Energy, Sustainability and the Environment
  • Electronic, Optical and Magnetic Materials
  • Energy Engineering and Power Technology

Cite this

In situ observation of deformation behavior of membrane electrode assembly under humidity cycles. / Kai, Yusuke; Kitayama, Yuki; Omiya, Masaki; Uchiyama, Tomoaki; Kumei, Hideyuki.

In: Journal of Fuel Cell Science and Technology, Vol. 11, No. 5, 051006, 2014.

Research output: Contribution to journalArticle

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