A stainless steel sheet for fuel cell separators comprises: a predetermined chemical composition; and fine precipitates containing Cr and Ti at a steel sheet surface, wherein an average equivalent circular diameter of the fine precipitates is 20 nm or more and 500 nm or less, and a number of the fine precipitates existing per 1 m.sup.2 at the steel sheet surface is three or more.

A separator for a fuel cell includes a metal separator base, crest sections, and a trough sections. Regions surrounded by the respective trough sections and a corresponding electrode layer each constitute a passage that supplies oxidation gas or fuel gas to the electrode layer. A first thin film is placed over the entire surfaces of the crest sections and the trough sections that face the corresponding electrode layer. The first thin film has conductivity and a corrosion resistance higher than that of the separator base. A second thin film having conductivity is placed at least on each of the parts of the first thin film that are placed on top surfaces of the crest sections. The second thin film on the top surface of each crest section has a groove. At least one end of the groove is connected to the passage.

A separator for a fuel cell includes a metal separator base, crest sections, and a trough sections. Regions surrounded by the respective trough sections and a corresponding electrode layer each constitute a passage that supplies oxidation gas or fuel gas to the electrode layer. A first thin film is placed over the entire surfaces of the crest sections and the trough sections that face the corresponding electrode layer. The first thin film has conductivity and a corrosion resistance higher than that of the separator base. A second thin film having conductivity is placed at least on each of the parts of the first thin film that are placed on top surfaces of the crest sections. The second thin film on the top surface of each crest section has a groove. At least one end of the groove is connected to the passage.

A separator for a fuel cell includes a separator base, crest sections, and trough sections. Regions surrounded by the respective trough sections and a corresponding electrode layer each constitute a passage that supplies oxidation gas or fuel gas to the electrode layer. A thin film having conductivity is placed at least on the top surface of each crest section. The thin film on the top surface of each crest section has a groove that connects the passages on the opposite sides of the crest section to each other. Each trough section has a flow resistance increasing portion on the downstream side of the groove in the flow direction of the gas. The flow resistance increasing portion reduces the cross-sectional flow area of the passage such that the cross-sectional flow area at the flow resistance increasing portion is smaller than that at the section to which the groove is connected.

A separator for a fuel cell includes a separator base, crest sections, and trough sections. Regions surrounded by the respective trough sections and a corresponding electrode layer each constitute a passage that supplies oxidation gas or fuel gas to the electrode layer. A thin film having conductivity is placed at least on the top surface of each crest section. The thin film on the top surface of each crest section has a groove that connects the passages on the opposite sides of the crest section to each other. Each trough section has a flow resistance increasing portion on the downstream side of the groove in the flow direction of the gas. The flow resistance increasing portion reduces the cross-sectional flow area of the passage such that the cross-sectional flow area at the flow resistance increasing portion is smaller than that at the section to which the groove is connected.

The present disclosure provides fuel cell units formed from a plurality of flow plate assemblies disposed in a stack configuration, with adjacent flow plate assemblies in the stack configuration disposed at an offset angle relative to each other. Fuel cell stacks can be formed from a plurality of the fuel cell units placed into a stack aligned with each other with no offset. The present disclosure also provides for methods of forming the fuel cell units, fuel cell stacks, and fuel cell systems containing the former.

The present disclosure provides fuel cell units formed from a plurality of flow plate assemblies disposed in a stack configuration, with adjacent flow plate assemblies in the stack configuration disposed at an offset angle relative to each other. Fuel cell stacks can be formed from a plurality of the fuel cell units placed into a stack aligned with each other with no offset. The present disclosure also provides for methods of forming the fuel cell units, fuel cell stacks, and fuel cell systems containing the former.

The disclosure relates to a method for using fuel cell. The fuel cell includes a container, wherein the container comprises a housing and a nozzle, and the housing defines through holes; the housing defines a chamber and an opening; the nozzle has a first end in air/fluid communication with the opening and a second end; and a membrane electrode assembly, which is flexible, on the container to form a curved membrane electrode assembly surrounding the chamber and covering the through holes, wherein the membrane electrode assembly comprises a proton exchange membrane having a first surface and a second surface, a cathode electrode on the first surface and an anode electrode on the second surface. The method includes at least partially immersing the fuel cell in a fuel; and supplying an oxidizing gas into the chamber.

The disclosure relates to a method for using fuel cell. The fuel cell includes a container, wherein the container comprises a housing and a nozzle, and the housing defines through holes; the housing defines a chamber and an opening; the nozzle has a first end in air/fluid communication with the opening and a second end; and a membrane electrode assembly, which is flexible, on the container to form a curved membrane electrode assembly surrounding the chamber and covering the through holes, wherein the membrane electrode assembly comprises a proton exchange membrane having a first surface and a second surface, a cathode electrode on the first surface and an anode electrode on the second surface. The method includes at least partially immersing the fuel cell in a fuel; and supplying an oxidizing gas into the chamber.

An object is to equalize the level of cooling along a top-bottom direction of a fuel cell stack. A fuel cell stack has an anode-side separator placed between a plurality of membrane electrode assemblies. The anode-side separator comprises a separator center area that is arranged to face a power generation area of the membrane electrode assembly; an outer peripheral portion that is extended from the separator center area to outer periphery and has a plurality of openings for cooling medium supply manifolds; and a rib that is firmed from a beam portion provided to separate the adjacent openings for cooling medium supply manifolds from each other, over an area between the openings for cooling medium supply manifolds and the separator center area.