| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain a diffusion layer for a fuel cell that is operable in a wide temperature region ranging from below freezing point up to high temperatures. <P>SOLUTION: The fuel cell diffusion layer is constituted to satisfy conditions expressed by (1): 22≥KΔP>14 [m<SP>2</SP>kPa], and (2): 0.28≤D/Dd<0.34 [-]. Here, K expresses permeability coefficient expressing permeation resistance of the diffusion layer that is a porous body, ΔP indicates capillary differential pressure of force applied to aqueous liquid in a pore of the diffusion layer, D shows diffusion coefficient expressing diffusion coefficient of steam inside the diffusion layer, and Dd shows diffusion coefficient of steam in the air. By this, compatibility of high temperature operating performance and below freezing point startability is promoted by promoting draining of water at low temperatures to reduce residual water, while drying of an electrolyte membrane is prevented by suppressing diffusion of steam at the high temperatures. <P>COPYRIGHT: (C)2011,JPO&INPIT |
