Abstract: A fuel cell stack includes a first end power generation unit and a first dummy unit adjacent to a power generation unit at one end of a stack body in a stacking direction. In the first end power generation unit, a first separator is stacked on the power generation unit, a first membrane electrode assembly is stacked on the first separator, a second separator is stacked on the first membrane electrode assembly, an electrically conductive plate is stacked on the second separator, and a third separator is stacked on the electrically conductive plate. A coolant is supplied to a coolant flow field formed between the power generation unit and the first end power generation unit, for cooling a second membrane electrolyte assembly of the power generation unit and the first membrane electrode assembly of the first end power generation unit.

Abstract: A method of actuating a fuel cell system equipped with a fuel cell is disclosed. The fuel cell system is supplied with reaction gases for generating electricity. The method includes the steps of: a first step for actuating the fuel cell in a low-temperature actuation mode to thereby warm up the fuel cell, if a low-temperature actuation condition is satisfied at a start-up of the fuel cell; and a second step for drying a membrane electrode assembly of the fuel cell, if a power generation capacity of the fuel cell is lower than a predetermined power generation capacity.

Abstract: A stop method for a fuel cell system including a fuel cell unit in which hydrogen is supplied to an anode, and air is supplied to a cathode so as to generate electrical power via an electrochemical reaction. The stop method includes the steps of stopping supply of hydrogen to the anode, electrically connecting the anode and the cathode via an electrical load, and supplying air to the anode.

Abstract: A fuel cell system includes a fuel cell and a supplying unit, which supplies reactive gases to the fuel cell. A control unit includes a power production effective area calculator calculates the areas of the electrodes available for power production as a power production effective area. A current density calculator which calculates a current density of the power production effective area calculated by the power production effective area calculator based on the total amount of power required by the fuel cell. A gas supply amount determiner determines the amount of reactive gas to be supplied to the fuel cell depending on the current density. A gas supply controller controls the supplying unit so as to supply the amount of reactive gas determined by the gas supply amount determiner to the fuel cell.

Abstract: A fuel cell system includes a fuel cell, an operation controller, a checking unit, a scavenging unit, an instructing unit, a temperature sensor, a humidifier and a humidification controller. The operation controller selects one of a normal operation mode and a low-temperature operation mode. The checking unit determines whether the fuel cell has been started up in the low-temperature operation mode. The instructing unit provides an instruction for a shutoff of electricity generation. When the scavenging unit conducts scavenging based on the checking unit determining that the fuel cell has been started in the low-temperature operation mode in response to an instruction for a shutoff of electricity generation and an actual temperature of the fuel cell is higher than a predetermined temperature, the humidification controller controls an amount of humidification according to the actual temperature.

Abstract: An oxygen-containing gas flow field is formed on a surface of a first metal separator. The oxygen-containing gas flow field is connected between an oxygen-containing gas supply passage and an oxygen-containing gas discharge passage. The oxygen-containing gas flow field comprises oxygen-containing gas flow grooves, and ends of the oxygen-containing gas flow grooves are extended outwardly beyond ends of electrode catalyst layer of a membrane electrode assembly, and connected to an inlet buffer and an outlet buffer. When the purging process is performed at the time of stopping operation of the fuel cell, the purging air supplied to the oxygen-containing gas flow field discharges water retained in the electrode catalyst layers from the ends to the outlet buffer.

Abstract: A first metal separator of a fuel cell comprises a metal plate, and a first seal member is formed integrally on both surfaces of an outer edge of the metal plate. A first rib having a frame shape is provided around an oxygen-containing gas supply passage or the like of the metal plate. The first rib has a rib surface spaced away from an inner end surface of the metal plate around the oxygen-containing gas supply passage or the like, toward the oxygen-containing gas supply passage or the like.

Abstract: A stop method for a fuel cell system that includes a fuel cell unit in which hydrogen is supplied to an anode, and air is supplied to a cathode so as to generate electrical power via an electrochemical reaction. The stop method includes the steps of stopping supply of hydrogen to the anode, and supplying air to the anode so as to discharge water remaining at the anode.

Abstract: A method of operating a fuel cell assembly and a fuel cell system use a simple construction to restrain deterioration of power generating performance of a fuel cell assembly at a startup in a subfreezing environment. If an ignition switch is turned off is STEP 1, a control unit determines in STEP 3 whether the temperature of a fuel cell assembly (the internal temperature of the fuel cell assembly) is lower than a predetermined temperature, which is higher than the temperature at which the water produced during power generation freezes. If the internal temperature of the fuel cell assembly is the predetermined temperature or higher, then the processing proceeds to STEP 4 wherein a power generating condition is adjusted to cause the internal temperature of the fuel cell assembly to rise. In STEP 5, an alarm device is actuated.

Abstract: After an ignition switch is turned off, in order to suppress operation of an air compressor and thereby reduce noise, liquid droplets residing in an oxygen-containing gas flow field as well as liquid droplets residing in a fuel gas flow field are removed during separate time periods, such that the flow rate in the oxygen-containing gas flow field and the flow rate in the fuel gas flow field do not become large at the same time. Then, an electrolyte membrane is dried using an oxygen-containing gas, in order to improve the performance upon starting a next operation.

Abstract: A fuel cell stack includes a stack body formed by stacking a plurality of power generation cells in a stacking direction. At one end of the stack body, first and second dummy cells are provided. At the other of the stack body, third and fourth dummy cells are provided. Each of the first to fourth dummy cells includes a first metal separator and a second metal separator. The first metal separator and a first metal separator of the power generation cell have substantially the same shape. The second metal separator and a second metal separator of the power generation cell have substantially the same shape.

Abstract: A fuel cell stack 10 includes a stacked structure 14 composed of a plurality of electricity-generating cells stacked successively, and dummy cells arranged at both ends in a stacking direction of the stacked structure 14. Each dummy cell 16 each includes a conductive plate 52 and first and second metallic separators 54, 56 which sandwich the conductive plate 52. The conductive plate 52 is formed of a metallic plate having substantially the same shape as that of the electrolytic membrane electrode assembly 22. The first and second metallic separators 54, 56 are structured in the same manner as the first and second metallic separators 24, 26 of the electricity-generating cell 12.

Abstract: A stop method for a fuel cell system that includes a fuel cell unit in which hydrogen is supplied to an anode, and air is supplied to a cathode so as to generate electrical power via an electrochemical reaction. The stop method includes the steps of stopping supply of hydrogen to the anode, and supplying air to the anode so as to discharge water remaining at the anode.

Abstract: A fuel cell stack which comprises a plurality of unit fuel cells laminated via separators, and is connected to external resistors each allowing a feeble current to flow to each unit fuel cell, whereby such problems as an open-circuit voltage generation and corrosion that may be caused by fuel gas remaining after operation shutdown can be resolved. A switch is preferably attached in series with an external resistor.

Abstract: A stop method for a fuel cell system that includes a fuel cell unit in which hydrogen is supplied to an anode, and air is supplied to a cathode so as to generate electrical power via an electrochemical reaction. The stop method includes the steps of stopping supply of hydrogen to the anode, and supplying air to the anode so as to discharge water remaining at the anode.

Abstract: The fuel cell system is equipped with a fuel cell for generating power by a reaction of fuel and oxidizer gases, a fuel gas flow passage for passing the fuel gas, an oxidizer gas flow passage for passing the oxidizer gas, a sweeping gas supply mechanism for sweeping any of the fuel and oxidizer gas flow passages by a sweeping gas, a sweeping determination mechanism for determining whether to perform sweeping by the sweeping gas supply mechanism, when receiving a stop request for stopping the fuel cell system, a pressure reduction mechanism for reducing a pressure within one of the flow passages lower than when determined not to perform the sweeping, when determined to perform the sweeping by the sweeping determination mechanism, and an actuation mechanism for actuating the sweeping gas supply mechanism after the pressure within the flow passage is reduced by the pressure reduction mechanism.

Abstract: When it is detected that the temperature of the fuel cell stack is at the freezing temperature of water or less (step S1), an operation mode using a freezing temperature starting up operation control map is selected (step S2). Freezing temperature starting up operation of the fuel cell stack is performed according to the freezing temperature starting up operation control map (step S3). Then, when it is detected that the temperature of the fuel cell stack exceeds the freezing temperature (step S4), the operation mode using the freezing temperature starting up operation control map is switched to an operation mode using a normal starting up operation control map (step S5). Thus, normal starting up operation is performed according to the normal starting up control map (step S6).

Abstract: A method of starting up at a subzero temperature a solid polymer electrolyte fuel cell stack that is formed by stacking a plurality of layers of separators and membrane electrode assemblies having a solid polymer electrolyte membrane and electrodes. The method includes a step of using a solid polymer electrolyte fuel cell stack in which the separators are made from metal and have a cross-sectional waveform structure, and a space that is formed between at least a portion of the separators and separators that are placed adjacent to this portion of the separators is used as a coolant flow passage.

Abstract: A fuel cell system includes a fuel cell, an oxidant gas passage, a cathode off-gas passage, a fuel gas passage, a circulation passage, an anode off-gas passage, a fuel shutoff valve, a supply device, a humidifier and a control device. The supply device supplies a scavenging gas, which is for scavenging the fuel cell, to the anode and the cathode. The humidifier humidifies the scavenging gas. The control device controls the supply device when the fuel cell is turned off so that supply of the fuel gas to the anode is shut off and the scavenging gas is supplied to the anode and the cathode, wherein supply of the scavenging gas to the cathode is conducted through the humidifier.

Abstract: A fuel cell stack is provided with an outlet side oxygen-containing gas communication hole. First and second oxygen-containing gas flow passage grooves are provided in the direction of the gravity while meandering in the horizontal direction on a surface of a first separator. The second oxygen-containing gas flow passage grooves communicate with the outlet side oxygen-containing gas communication hole via second oxygen-containing gas connecting flow passages. The lowest position of the second oxygen-containing gas flow passage grooves 44 in the direction of gravity is higher than the bottom of the outlet side oxygen-containing gas communication hole 38b by the height h.