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Modeling the variation of relative humidity along the cathode feed channel of a PEM fuel cell

Baghalha, M ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1149/1.3635737
  3. Abstract:
  4. A water balance model for a local location across a PEFC was previously developed. Below a critical current density, water removal out of the cathode catalyst layer (CCL) to cathode side proceeds by vapor diffusion. Above the critical current density, excessive water generation leads to the build-up of an excess liquid pressure in the CCL, which acts as a driving force for hydraulic fluxes to polymer electrolyte membrane (PEM) and gas diffusion media (GDM) of cathode. These fluxes are a function of local cell operating conditions such as the local relative humidity in cathode feed channel (CFC). Assuming no water condensation/evaporation in the CFC, water vapor balance along CFC under steady state condition was considered in the present study. A simplified 1D analytical solution for prediction of RH variation along the CFC was developed in this work. An adjustable design factor was also introduced in the governing equations to compensate for deviations from such simplifying assumptions as the isothermal condition. For typical PEFC operating conditions, the model showed significant variations of the relative humidity and water fluxes along the CFC
  5. Keywords:
  6. Cathode catalyst layers ; Design factors ; Driving forces ; Feed channel ; Gas diffusion media ; Governing equations ; Isothermal conditions ; Liquid pressure ; Operating condition ; PEM fuel cell ; Polymer electrolyte membranes ; Simplifying assumptions ; Steady-state condition ; Vapor diffusion ; Water balance models ; Water condensation ; Water flux ; Water generation ; Water removal ; Cathodes ; Polyelectrolytes ; Polymers ; Water vapor ; Proton exchange membrane fuel cells (PEMFC)
  7. Source: ECS Transactions ; Volume 41, Issue 1 , 2011 , Pages 2073-2082 ; 19385862 (ISSN) ; 9781607682547 (ISBN)
  8. URL: http://ecst.ecsdl.org/content/41/1/2073