The present invention provides a fuel cell stack with enhanced freeze-thaw durability. In particular, the fuel cell stack includes a gas diffusion layer between a membrane-electrode assembly and a bipolar plate. The gas diffusion layer has a structure that reduces contact resistance in a fuel cell and is cut at a certain angle such that the machine direction (high stiffness direction) of GDL roll is not in parallel with the major flow field direction of the bipolar plate, resulting in an increased GDL stiffness in a width direction perpendicular to a major flow field direction of a bipolar plate.

The present invention provides a fuel cell stack with enhanced freeze-thaw durability. In particular, the fuel cell stack includes a gas diffusion layer between a membrane-electrode assembly and a bipolar plate. The gas diffusion layer has a structure that reduces contact resistance in a fuel cell and is cut at a certain angle such that the machine direction (high stiffness direction) of GDL roll is not in parallel with the major flow field direction of the bipolar plate, resulting in an increased GDL stiffness in a width direction perpendicular to a major flow field direction of a bipolar plate.

Redox flow battery 1 include cell frame 20 having recess 21, 22, at least one sheet-like electrode 11, 13 received in recess 21, 22, membrane 15 stacked on cell frame 20 to cover recess 21, 22, and bipolar current collecting member 40 penetrating cell frame 20 at recess 21, 22 and electrically connected to at least one electrode 11, 13, wherein cell frame 20 has flow channels 31-38 communicating with recess 21, 22 so as to allow a fluid containing an active material to flow through recess 21, 22 parallel to membrane 15, and wherein at least one electrode 11, 13 is disposed in recess 21, 22 at an angle where at least one electrode 11, 13 intersects membrane 15.

Redox flow battery 1 include cell frame 20 having recess 21, 22, at least one sheet-like electrode 11, 13 received in recess 21, 22, membrane 15 stacked on cell frame 20 to cover recess 21, 22, and bipolar current collecting member 40 penetrating cell frame 20 at recess 21, 22 and electrically connected to at least one electrode 11, 13, wherein cell frame 20 has flow channels 31-38 communicating with recess 21, 22 so as to allow a fluid containing an active material to flow through recess 21, 22 parallel to membrane 15, and wherein at least one electrode 11, 13 is disposed in recess 21, 22 at an angle where at least one electrode 11, 13 intersects membrane 15.

A gas permeable or breathable electrode and method of manufacture thereof. In one example there is an electrolytic cell having an electrode comprising a porous material, wherein gas produced at the electrode diffuses out of the cell via the porous material. In operation the gas is produced at the at least one electrode without substantial bubble formation. In another example there is an electrode having a porous conducting material with a hydrophobic layer or coating applied to a side of the porous conducting material. A catalyst may be applied to another side. The gas permeable or breathable electrode can be used in an electrolytic cell, electrochemical cell, battery and/or fuel cell. Gas produced at the electrode diffuses out of a cell via at least part of the electrode, separating the gas from the reaction at the electrode.

An illustrative example embodiment of a fuel cell component includes a graphite substrate, a polytetrafluoroethylene (PTFE) layer adjacent a portion of the graphite substrate, and a plurality of segments of acrylic adhesive between the portion of the graphite substrate and the PTFE layer. The acrylic adhesive secures the PTFE layer to the portion of the graphite substrate. There is spacing between adjacent ones of the segments.

An illustrative example embodiment of a fuel cell component includes a graphite substrate, a polytetrafluoroethylene (PTFE) layer adjacent a portion of the graphite substrate, and a plurality of segments of acrylic adhesive between the portion of the graphite substrate and the PTFE layer. The acrylic adhesive secures the PTFE layer to the portion of the graphite substrate. There is spacing between adjacent ones of the segments.

A fuel cell includes: a membrane electrode assembly including an electrolyte membrane, catalyst layers stacked on both sides of the electrolyte membrane, and two or more porous bodies having different moduli of elasticity and provided on a surface of one of the catalyst layers; a separator defining a gas flow passage between the separator and the membrane electrode assembly; and a frame body surrounding an outer periphery of the electrolyte membrane. A porous body adjacent to the separator out of the two or more porous bodies includes an outer edge portion including an outer extending portion extending to overlap with the frame body. An elastic body is provided between the outer extending portion and the frame body.

A fuel cell includes: a membrane electrode assembly including an electrolyte membrane, catalyst layers stacked on both sides of the electrolyte membrane, and two or more porous bodies having different moduli of elasticity and provided on a surface of one of the catalyst layers; a separator defining a gas flow passage between the separator and the membrane electrode assembly; and a frame body surrounding an outer periphery of the electrolyte membrane. A porous body adjacent to the separator out of the two or more porous bodies includes an outer edge portion including an outer extending portion extending to overlap with the frame body. An elastic body is provided between the outer extending portion and the frame body.

The present invention relates to a gas diffusion layer for a fuel cell, made of a carbon substrate grafted with at least one aromatic group having formula (II):

##STR00001##

wherein: the asterisk * designates a carbon atom with no hydrogen and no R.sup.i group, with i=1 to 5, and covalently bonded to the carbon substrate; at least two of the R.sup.1, R.sup.2, R.sup.3, R.sup.4, and R.sup.5 groups are different from a hydrogen atom; at least two of the R.sup.1, R.sup.2, R.sup.3, R.sup.4, and R.sup.5 groups are hydrophobic groups or hydrophilic groups or a hydrophobic group and a hydrophilic group.