An electrochemical device includes at least one electrochemical cell, including a membrane electrode assembly and bipolar plates through which at least one discharge manifold passes, the membrane electrode assembly including an active zone and a connection zone; at least one hydrogen sensor including an anode positioned in the connection zone and including a catalyst suitable for ensuring the oxidation of the hydrogen, and a cathode opposite the anode; a voltage source; a current sensor; and a computing unit, suitable for detecting the presence of hydrogen from the measured value of the electric current.

An electrochemical device includes at least one electrochemical cell, including a membrane electrode assembly and bipolar plates through which at least one discharge manifold passes, the membrane electrode assembly including an active zone and a connection zone; at least one hydrogen sensor including an anode positioned in the connection zone and including a catalyst suitable for ensuring the oxidation of the hydrogen, and a cathode opposite the anode; a voltage source; a current sensor; and a computing unit, suitable for detecting the presence of hydrogen from the measured value of the electric current.

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.

A porous body for a fuel cell is interposed between a membrane-electrode assembly (MEA) and a bipolar plate to form a gas channel through which a reactant gas flows in a predetermined direction, the porous body including: a main body disposed to contact the bipolar plate; and a plurality of ribs each including a land portion disposed to contact the MEA and a connecting portion connecting the land portion to the main body, in which an area of the land portion is gradually narrowed from an upstream part to a downstream part of the gas channel.

A porous body for a fuel cell is interposed between a membrane-electrode assembly (MEA) and a bipolar plate to form a gas channel through which a reactant gas flows in a predetermined direction, the porous body including: a main body disposed to contact the bipolar plate; and a plurality of ribs each including a land portion disposed to contact the MEA and a connecting portion connecting the land portion to the main body, in which an area of the land portion is gradually narrowed from an upstream part to a downstream part of the gas channel.

A separator for a fuel cell and a unit cell of a fuel cell are disclosed. The separator for the fuel cell includes a separation plate having a coupling protrusion that protrudes from an edge thereof, and a porous body having a coupling hole into which the coupling protrusion is fixedly inserted, so that the porous body is coupled to a plane of the separation plate. The porous body defining a path in which reactive gases flow.

A fuel cell includes a fuel cell stack having a stacked body with a plurality of stacked unit cells, an end plate unit, and a gas manifold penetrating the stacked body and the end plate unit in a stacking direction for a flow of reaction gas. The fuel cell also includes a valve that is provided between the end plate unit and gas piping and includes an in-valve flow path for communicating the gas manifold and the gas piping and a valve element. The gas manifold includes a stacked body manifold and an end plate unit flow path. When the fuel cell stack is arranged so that a manifold bottom portion is horizontal, a bottom portion of an opening on the valve side in the end plate unit flow path is arranged above the manifold bottom portion.