A fuel cell system according to an embodiment includes: a fuel cell that is supplied with a fuel gas to generate electric power; a determination unit that determines a mixing ratio of inert gas in the fuel gas to be supplied to the fuel cell; and an operation control unit that changes an operation condition of the fuel cell system, based on the mixing ratio of inert gas determined by the determination unit.

A fuel cell system includes an oxygen-containing gas supply that supplies air to a fuel cell module, a fuel supply that supplies a fuel gas to a fuel cell, a power regulator that regulates supply of a generated current to a load, and a controller. The controller includes a plurality of relational expressions predefined and representing a relationship between a generation current level of the fuel cell and at least one of an air utilization or a fuel utilization, and selects at least one of the plurality of relational expressions based on an increase rate of the current set by the power regulator to increase the generation current level for an independent operation to be performed in, for example, an outage.

Fuel cell arrangement having an improved efficiency. The arrangement comprises one or more fuel cell units 110 and a methanation unit 200 and a control unit 300. The fuel cell unit comprises a water inlet 111, a hydrogen outlet 112 and an oxygen outlet 113. The methanation unit comprises a catalyst 222, a hydrogen inlet 213, a carbon oxide inlet 214 having a first controllable valve 215 and a methane outlet 216, wherein the hydrogen outlet of the first fuel cell unit is coupled to the hydrogen inlet of the methanation unit, and the methanation unit is adapted to convert hydrogen and carbon oxide into methane, wherein the control unit is adapted to control the first controllable valve so as to obtain an optimum converting process to convert hydrogen and carbon oxide into methane.

A method for enriching the oxygen fed to a fuel cell cathode intake comprises receiving at the cathode intake an oxidant from the air, storing oxygen in an adsorber coupled to the cathode intake, and adding the stored oxygen from the adsorber to the oxidant at the cathode intake during high current density operation. A fuel cell system comprises a membrane, an anode on one side of the membrane, and a cathode, coupled to a blocking member, on a second side of the membrane. The cathode comprising an intake configured to allow an oxidant to flow through the cathode, and an outlet configured to discharge unreacted oxygen from the cathode, an adsorber, coupled to the blocking member, configured to store oxygen for adding to the oxidant flowing through the cathode intake during high current density operation.

In a fuel cell system, a preceding-stage fuel cell and a following-stage fuel cell are connected via a fuel flow path. The fuel cell system includes a reformer that supplies reformed gas to the preceding-stage fuel cell; an acquisition unit that acquires the amount of heat generation and the amount of heat absorption of the preceding-stage fuel cell; and a control unit that controls at least one of the amount of current of the preceding-stage fuel cell, the flow rate of air to be supplied to the reformer, and the temperature of the preceding-stage fuel cell if the amount of heat absorption acquired by the acquisition unit is larger than the amount of heat generation acquired by the acquisition unit.

The invention relates to a method for controlling the functioning of a fuel cell comprising at least one membrane, comprising the following steps: putting at least two conductive means in contact with two different surface elements of the same first conductive plate, said plate being able to be a distribution plate belonging to a first cell, measurement of one or more electrical voltages between said conductive means electrically connected to an electrical-voltage measurement device.

A fuel cell comprises an anode having an inner face and an outer face fluidly communicable with a fuel; a cathode having an inner face ionically communicable with and physically separated from the anode inner face, and having an outer face fluidly communicable with an oxidant; and at least one movable guard movable over at least one of the anode outer face, cathode outer face, anode inner face, and cathode inner face. The guard has a structure sufficient to block at least part of one or more of the anode's communication with the fuel, the cathode's communication with the oxidant, and the ionic communication between the anode and cathode thereby reducing a maximum potential active area of the fuel cell to an effective active area of the fuel cell.

A method of operating a fuel cell assembly comprising a plurality of fuel cells connected together for collectively providing power to a load, each fuel cell including an anode and a cathode, the method comprising selectively providing an electrical connection between the anode and the cathode of at least one of the fuel cells of the assembly for lowering the voltage across the fuel cell independent of the load.

Fuel cell arrangement having an improved efficiency. The arrangement comprises one or more fuel cell units 110 and a methanation unit 200 and a control unit 300. The fuel cell unit comprises a water inlet 111, a hydrogen outlet 112 and an oxygen outlet 113. The methanation unit comprises a catalyst 222, a hydrogen inlet 213, a carbon oxide inlet 214 having a first controllable valve 215 and a methane outlet 216, wherein the hydrogen outlet of the first fuel cell unit is coupled to the hydrogen inlet of the methanation unit, and the methanation unit is adapted to convert hydrogen and carbon oxide into methane, wherein the control unit is adapted to control the first controllable valve so as to obtain an optimum converting process to convert hydrogen and carbon oxide into methane.

A method of estimating hydrogen crossover loss of a fuel cell system including a stack for producing power through a reaction of hydrogen serving as fuel and air serving as an oxidizer includes driving the fuel cell system; estimating a hydrogen crossover rate right after a channel of an anode is purged; determining whether a cell voltage of a fuel cell is normal; and comparing the estimated hydrogen crossover rate with a predetermined reference value based on a result of the determining of whether the cell voltage of the fuel cell is normal to determine whether a pinhole or leakage occurs. Accordingly, whether a pinhole or leakage occurs in the fuel cell system may be more effectively sensed.