Patent ID: 6743543
Filing Date: 2004-06-01
Classification: H01M,Y02E

Abstract:
A fuel cell comprising:a membrane electrode assembly, comprising an electrolyte disposed between and in intimate contact with an anode forming a first major side of the membrane electrode assembly and a cathode forming a second major side of the membrane electrode assembly; and a layer of electrically conductive variable porosity gas diffusion material disposed on and in intimate contact with at least one of the major sides of the membrane electrode assembly, wherein porosity of the variable porosity gas diffusion material at localized areas on the variable porosity gas diffusion layer correlates to a temperature differential from a threshold value at corresponding areas on the membrane electrode assembly side in contact with the variable porosity gas diffusion layer, wherein the porosity of the variable porosity gas diffusion material decreases in response to a decrease in temperature at corresponding areas on the membrane electrode assembly side in contact with the variable porosity gas diffusion layer, below a threshold value, and wherein the variable porosity gas diffusion material further comprises a layer made of electrically conductive materials distributed such that the resulting layer is micro or nano porous.