Gas diffusion through differently structured gas diffusion layers of PEM fuel cells

Abstract Proton exchange membrane fuel cell (PEMFC) gas diffusion layers (GDLs) play important parts in diffusing gas, discharging liquid water, and conducting electricity, etc. When liquid water is discharged through GDL to gas channel, there will be some pores of GDLs occupied by liquid water. In this study, based on a one-dimensional model, the distribution of liquid water phase saturation is analyzed for different GDL structures including GDL with uniform porosity, GDL with sudden change porosity (GDL with microporous layer (MPL)) and GDL with gradient porosity distribution. The effect on gas diffusion of the changes of porosity and liquid saturation due to water remaining in GDL pores is calculated. The conclusions are that for uniform porosity GDL, the gas diffusion increases with the increase of porosity and contact angle and increases with the decrease of the thickness of GDL; for GDL with MPL, the larger the MPL porosity and the thinner the MPL thickness are, the stronger the gas diffusion is; for gradient change porosity GDL with the same average equivalent porosity, the larger the porosity gradient is, the more easily the gas diffuses. The optimization for GDL gradient structure shows that the GDL with a linear porosity distribution of 0.4 x + 0.4 is the best of the computed cases.

[1]  Qing-Ming Wang,et al.  Multi-gas transportation and electrochemical performance of a polymer electrolyte fuel cell with complex flow channels , 2003 .

[2]  Brant A. Peppley,et al.  Modeling the Influence of GDL and flow-field plate parameters on the reaction distribution in the PEMFC cathode catalyst layer , 2005 .

[3]  Zhigang Qi,et al.  Improvement of water management by a microporous sublayer for PEM fuel cells , 2002 .

[4]  Falin Chen,et al.  Effects of porosity change of gas diffuser on performance of proton exchange membrane fuel cell , 2003 .

[5]  S. F. Lee,et al.  Oxygen mass transfer in PEM fuel cell gas diffusion layers , 2004 .

[6]  Ned Djilali,et al.  A two-dimensional analysis of mass transport in proton exchange membrane fuel cells , 1999 .

[7]  Jin Hyun Nam,et al.  Effective diffusivity and water-saturation distribution in single- and two-layer PEMFC diffusion medium , 2003 .

[8]  Jinsheng Xiao,et al.  Effects of porosity distribution variation on the liquid water flux through gas diffusion layers of PEM fuel cells , 2006 .

[9]  Chao-Yang Wang,et al.  Two-phase transport and the role of micro-porous layer in polymer electrolyte fuel cells , 2004 .

[10]  Jenn-Jiang Hwang,et al.  Heat/mass transfer in porous electrodes of fuel cells , 2006 .

[11]  Shaoping Li,et al.  A Three Dimensional CFD Model for PEMFC , 2004 .

[12]  Sadik Kakac,et al.  Two‐dimensional model for proton exchange membrane fuel cells , 1998 .

[13]  Nicos Martys,et al.  Diffusion in partially-saturated porous materials , 1999 .

[14]  T. Springer,et al.  Polymer Electrolyte Fuel Cell Model , 1991 .

[15]  Anzhong Gu,et al.  Three dimensional, two phase flow mathematical model for PEM fuel cell: Part I. Model development , 2004 .

[16]  Wayne Moore,et al.  Effect of Pore Structure, Randomness and Size on Effective Mass Diffusivity , 2002 .

[17]  Z. H. Wang,et al.  Two-phase flow and transport in the air cathode of proton exchange membrane fuel cells , 2000 .

[18]  T. Nguyen,et al.  Multicomponent transport in porous electrodes of proton exchange membrane fuel cells using the interdigitated gas distributors , 1999 .

[19]  Tae-Hee Lee,et al.  Influence of pore-size distribution of diffusion layer on mass-transport problems of proton exchange membrane fuel cells , 2002 .

[20]  Jean St-Pierre,et al.  In-plane gradients in fuel cell structure and conditions for higher performance , 2003 .

[21]  L. J. Lee,et al.  Effective Mass Diffusivity in Composites , 2002 .

[22]  Ramin Roshandel,et al.  The effects of porosity distribution variation on PEM fuel cell performance , 2005 .