Effect of clamping pressure on ohmic resistance and compression of gas diffusion layers for polymer electrolyte fuel cells

Research output: Contribution to journalArticlepeer-review

Authors

  • Thomas J. Mason
  • Jason Millichamp
  • Tobias P. Neville
  • Bruno G. Pollet
  • Daniel J L Brett

Colleges, School and Institutes

External organisations

  • University College London
  • University of Birmingham
  • University of the Western Cape

Abstract

This paper describes the use of an in situ analytical technique based on simultaneous displacement and resistance measurement of gas diffusion layers (GDLs) used in polymer electrolyte fuel cells (PEFCs), when exposed to varying compaction pressure. In terms of the losses within fuel cells, the ohmic loss makes up a significant portion. Of this loss, the contact resistance between the GDL and the bipolar plate (BPP) is an important constituent. By analysing the change in thickness and ohmic resistance of GDLs under compression, important mechanical and electrical properties are obtained. Derived parameters such as the 'displacement factor' are used to characterise a representative range of commercial GDLs. Increasing compaction pressure leads to a non-linear decrease in resistance for all GDLs. For Toray paper, compaction becomes more irreversible with pressure with no elastic region observed. Different GDLs have different intrinsic resistance; however, all GDLs of the same class share a common compaction profile (change in resistance with pressure). Cyclic compression of Toray GDL leads to progressive improvement in resistance and reduction in thickness that stabilises after ∼10 cycles.

Details

Original languageEnglish
Pages (from-to)52-59
Number of pages8
JournalJournal of Power Sources
Volume219
Publication statusPublished - 1 Dec 2012