A fuel cell stack at least includes a stack body formed by stacking a plurality of power generation cells in a stacking direction and a first dummy cell provided at one end of the stack body in the stacking direction. The power generation cell includes a membrane electrode assembly. The first dummy cell includes a dummy assembly formed by stacking together three electrically conductive porous bodies each having a different surface size, a dummy resin frame member formed around the dummy assembly, and dummy separators.

A plurality of anode wavy portions provided in an anode separator of a fuel cell have wavy patterns in the same phase, and are arranged in an amplitude direction of the anode wavy portions at a first pitch. A plurality of cathode wavy portions provided in a cathode separator have wavy patterns in the same phase but in reverse phase with respect to the anode wavy portions, and are arranged in an amplitude direction of the cathode wavy portions at a second pitch. The first pitch and the second pitch have different sizes.

A plurality of anode wavy portions provided in an anode separator of a fuel cell have wavy patterns in the same phase, and are arranged in an amplitude direction of the anode wavy portions at a first pitch. A plurality of cathode wavy portions provided in a cathode separator have wavy patterns in the same phase but in reverse phase with respect to the anode wavy portions, and are arranged in an amplitude direction of the cathode wavy portions at a second pitch. The first pitch and the second pitch have different sizes.

Fuel cell stack assemblies (100) have a positive end plate (200) and a negative end plate (300), The end plates (200, 300) can be formed from a central structural element (220, 320) with an insulating end plate cover (210, 310) and an insulating end plate manifold (230, 330). A plurality of cathode plates (150) and a plurality of fuel cell assemblies (250) can be arranged in a stack having an alternating pattern of cathode plates (150) and fuel cell assemblies (250), with the positive end plate (200) and the negative end plate (300) provided on either end of the stack of cathode plates and fuel cell assemblies.

Fuel cell stack assemblies (100) have a positive end plate (200) and a negative end plate (300), The end plates (200, 300) can be formed from a central structural element (220, 320) with an insulating end plate cover (210, 310) and an insulating end plate manifold (230, 330). A plurality of cathode plates (150) and a plurality of fuel cell assemblies (250) can be arranged in a stack having an alternating pattern of cathode plates (150) and fuel cell assemblies (250), with the positive end plate (200) and the negative end plate (300) provided on either end of the stack of cathode plates and fuel cell assemblies.

In this fuel cell, a cathode-side porous film that covers a cathode electrode is interposed between the cathode electrode and an air supply layer, the cathode electrode constituting electrolyte film/electrode structures. In addition, breathing holes are formed in the cathode-side porous film, and the air flowing through air supply passages passes through the breathing holes and is supplied to the cathode electrode.

Fuel cell assemblies comprising at least one thermally compensated coolant channel are provided. The thermally compensated coolant channel has a cross-sectional area that decreases in the coolant flow direction along at least a portion of the channel length. In some embodiments, such thermally compensated coolant channels can be used to provide substantially uniform heat flux, and substantially isothermal conditions, in fuel cells operating with substantially uniform current density.

Fuel cell assemblies comprising at least one thermally compensated coolant channel are provided. The thermally compensated coolant channel has a cross-sectional area that decreases in the coolant flow direction along at least a portion of the channel length. In some embodiments, such thermally compensated coolant channels can be used to provide substantially uniform heat flux, and substantially isothermal conditions, in fuel cells operating with substantially uniform current density.

The preset disclosure provides a catalyst layer that has a small contact resistance with a gas diffusion layer and excellent gas diffusion properties. The catalyst layer for a fuel cell has a uniform thickness and includes fibrous conductive members and catalyst particles. The fibrous conductive members are inclined relative to a surface direction of the catalyst layer, and a lengthwise direction of the fibrous conductive members, on average, matches a first direction.

A flow field plate for a fuel cell, the flow field plate is provided with a plurality of fluid channels wherein at least one split block is provided between the fluid channels, at least one auxiliary microflow-channel is arranged in the split block, the microflow-channel changes flow rate and flow pressure of fluid at different sites along the fluid channel by having a depth and a width smaller than a depth and a width of the fluid channel at a confluent segment and also smaller than a depth and a width of the fluid channel at a diverging segment, so as to generate a pressure difference that forces fluid to flow into a diffusion layer. The flow field plate adjusts flow rate and pressure of fluid at different sites along the fluid channel, so as to transmit the reaction medium more effectively and removes generated water more effectively.