Abstract: An anode includes: (1) a current collector; and (2) an interfacial layer disposed over the current collector. The interfacial layer includes an ion-conductive organic network including anionic coordination units, organic linkers bonded through the anionic coordination units, and counterions dispersed in the ion-conductive organic network.

Abstract: A power generation device includes a filter holder that is a container filled with water and a filter member. The filter member is composed of porous glass in a form of a plate and arranged in the filter holder between a first space upstream from the filter member and a second space downstream from the filter member. The filter member allows hydrogen ions to pass therethrough more easily than hydroxide ions. The power generation device generates electric power based on a potential difference between the first space and the second space when a water flow from the first space toward the second space is produced in the filter member. The water flow flows along a direction of thickness of the filter member.

Abstract: A volatile liquid refueling apparatus, which includes a probe including an outer collar, and a receiver including a receiving collar, where the outer collar of the probe and the receiving collar of the receiver are configured to join to create a vapor-tight enclosure, and where the receiver further includes a dual locking mechanism whereby the apparatus can be locked in either an open position or a closed position.

Abstract: A chemical reactor and method for operation. The reactor enables N pairwise fluid contacts among k chemical fluids, with k?2 and N?4 and comprises: a reaction layer extending in a plane subtended by two directions; N chemical cells, each including two circuit portions, designed for enabling circulation of two of the k chemical fluids, respectively, the two circuit portions intersecting each other, thereby enabling one pairwise fluid contact for the two of the k chemical fluids; and a fluid distribution circuit comprising: k sets of inlet orifices sequentially alternating along lines parallel to one of the two directions, for respectively dispensing k chemical fluids to the reaction layer; and k sets of outlet orifices sequentially alternating along lines parallel to the inlet orifices, for respectively collecting k chemical fluids from the reaction layer, and wherein, each circuit portion connects an inlet orifice to an outlet orifice.

Abstract: In a fuel cell system including a fuel cartridge and a fuel supply module, the fuel cartridge includes at least two ports, wherein a first port from among the at least two ports is a fuel inlet port and a second port from among the at least two ports is a fuel outlet port. The fuel cartridge may also include a fuel pouch or the fuel cartridge itself may be the fuel pouch. The fuel supply module may include a fuel circulation structure that circulates the fuel before the fuel is supplied to the stack. The fuel cell system may be equipped with an electronic apparatus and serve as a source of power.

Abstract: A method of and fuel cell system for limiting an amount of a fuel crossing over a membrane in a fuel cell, the method including determining an appropriate molecular ratio of the fuel and water for a fuel-water mixture 503; and controlling an amount of the fuel-water mixture that is available to an anode side of the membrane 507 in the fuel cell according to an amount of the fuel that will be electro-oxidized by the fuel cell. The fuel cell system includes a fuel cell membrane 103 having an anode layer 107, a cathode layer 109, and an electrolyte layer 111 where the cathode layer is exposed to an oxygen source, and a fuel delivery system 105 including a fuel chamber 119 disposed around and proximate to the anode layer at a side opposite to the electrolyte layer, the fuel delivery system implementing the method above.

Abstract: A method of operating a fuel cell system includes characterizing the fuel or fuels being provided into the fuel cell system, characterizing the oxidizing gas or gases being provided into the fuel cell system, and calculating at least one of the steam:carbon ratio, fuel utilization and oxidizing gas utilization based on the step of characterization.

Abstract: A fuel cell system whose fuel loss caused by the crossover of the fuel is small and which can be operated economically. The fuel cell system includes a fuel cell 10, a primary feeding system 12 for feeding a primary fuel which is a liquid fuel to the fuel cell 10, a secondary feeding system 13 for feeding a secondary fuel which is a liquid fuel whose saturation vapor pressure is lower than that of the primary fuel to the fuel cell 10, a ECU 30 for controlling each part so that the primary fuel in the fuel cell is replaced with the secondary fuel when terminating the operation of the fuel cell 10.

Abstract: A gas detection system is configured to detect a preset gas in a predetermined space. The gas detection system includes a gas concentration detector constructed to detect a gas concentration of the preset gas, a recording assembly, a notification module, and a decision module. When the gas concentration detected by the gas concentration detector is higher than a preset first reference value, the decision module controls the notification module to give notice. When the detected gas concentration is higher than a preset second reference value but is lower than the preset first reference value, on the other hand, the decision module controls the notification module to give no notice but record a specific piece of information into the recording assembly. This arrangement of the gas detection system enables the user to readily detect deterioration of a device utilizing a fuel, for example, fuel cells.

Abstract: A fuel cell system for generating a hydrogen test pulse includes a fuel cell stack having an anode inlet in fluid communication with a hydrogen source via a fuel spending line, a cathode inlet in fluid communication with an oxidant source, and an anode outlet and a cathode outlet in fluid communication with an exhaust line. An electric pressure regulator is in fluid communication with the fuel spending line. An overpressure valve is in fluid communication with an overpressure line, which is in fluid communication with the fuel spending line between the electric pressure regulator and the fuel cell stack. A hydrogen sensor is in communication with the exhaust line, and is configured to measure the hydrogen test pulse.

Abstract: A system for converting a waste stream to energy including a water purification device that outputs purified water and a waste stream that includes an electrolyte, a wind and electrolytic energy generation device that receives the waste stream from the water purification device and outputs energy based on the electrolyte present in the waste stream and a power distribution system which receives and stores the energy from the wind and electrolytic energy generation device. The water purification device is further connected to the power distribution system and receives energy enabling further operation of the water purification device.

Abstract: Loss of flow battery electrode catalyst layers during self-discharge or charge reversal may be prevented by establishing and maintaining a negative electrolyte imbalance during at least parts of a flow battery's operation. Negative imbalance may be established and/or maintained actively, passively or both. Actively establishing a negative imbalance may involve detecting an imbalance that is less negative than a desired threshold, and processing one or both electrolytes until the imbalance reaches a desired negative level. Negative imbalance may be effectively established and maintained passively within a cell by constructing a cell with a negative electrode chamber that is larger than the cell's positive electrode chamber, thereby providing a larger quantity of negative electrolyte for reaction with positive electrolyte.

Abstract: The present invention relates to an apparatus for steam purging a solid oxide fuel cell stack. Purging the SOFC stack with steam has a physical flushing effect, removing carbon monoxide containing reformate and free oxygen gas from the anode area thereby reducing the potential for nickel oxide or nickel carbonyl formation.

Abstract: In certain embodiments of the present disclosure, a proton exchange membrane fuel cell is described. The fuel cell includes a twin-cell electrochemical filter. A flow of reformate H2 and pulse potential are switched between each respective filter cell such that when CO-contaminated H2 is fed to one filter cell, generally simultaneously a pulse potential is applied to the other filter cell.

Abstract: A method of operating a fuel cell system includes characterizing the fuel or fuels being provided into the fuel cell system, characterizing the oxidizing gas or gases being provided into the fuel cell system, and calculating at least one of the steam:carbon ratio, fuel utilization and oxidizing gas utilization based on the step of characterization.

Abstract: The amount of fuel supplied to a fuel cell is set to a second set value Qm2 smaller than a first set value Qm1 determined based on a load. Then, an output current Ifcr of the fuel cell with the fuel supply amount set to the second set value Qm2 is detected. The output current Ifcr is compared with a reference value Iref for determining mild deterioration to determine whether the fuel cell has deteriorated from the comparison result. If a determination that the fuel cell has deteriorated is made, the fuel supply amount is reset to a third set value Qm3 larger than the second set value Qm2.

Abstract: The provided is a mixed reactant fuel cell system that includes a fuel cell body including a membrane-electrode assembly, a fuel tank, and a fuel pump. The fuel tank stores a mixed fuel including a hydrocarbon-based fuel and hydrogen peroxide (H2O2). The hydrogen peroxide (H2O2) acts as an oxidant. The fuel pump supplies the mixed fuel into the fuel cell body to generate electricity. An anode included in the membrane-electrode assembly includes a catalyst that selectively activates the oxidation reaction of the hydrocarbon-based fuel. A cathode included in the membrane-electrode assembly includes a catalyst that selectively activates the reduction reaction of the oxidant in the cathode. Therefore, when the mixed fuel is injected into both of the anode and the cathode, only an oxidation reaction of the fuel is carried out in the anode, and only a reduction reaction of the oxidant is carried out in the cathode.

Abstract: An improved anode material for a lithium ion battery is disclosed. The improved anode material can improve both electric conductivity and the mechanical resilience of the anode, thus drastically increasing the lifetime of lithium ion batteries.

Abstract: A system and method for detecting small hydrogen leaks in an anode of a fuel cell system. The method includes determining that a shut-down sequence has begun, and if so, deplete the cathode side of a fuel cell stack of oxygen. The method then increases the pressure of the anode side of the fuel cell stack to a predetermined set-point, and monitors the pressure decay of the anode side of the stack. The method compares the rate of pressure decay to an expected pressure decay rate, and if the measured pressure decay rate exceeds the expected pressure decay rate by a certain threshold, determines that a potential leak exists.

Abstract: A system and method for correcting an estimation of nitrogen in an anode side of a fuel cell stack. The system includes a fuel cell stack and a pressure sensor for measuring pressure in an anode sub-system. The system also includes a controller configured to control the estimation of nitrogen permeation from the cathode side to the anode side of the stack, where the controller determines if the pressure in the anode sub-system equilibrates with atmospheric pressure in a shorter period of time after shutdown compared to the time necessary for the anode sub-system to reach approximately atmospheric pressure after a previous shutdown or calibrated time value, and corrects the estimation of nitrogen in the anode side of the stack if the pressure equilibrates in a shorter period of time.

Abstract: A direct methanol fuel cell (DMFC) system including: a separator receiving a gas-liquid mixture discharged from a stack and separating the mixture to gas and a liquid; a methanol cartridge storing high concentration methanol; and a fuel mixer for methanol dilution. The separator and the fuel mixer are separate structures, each including an agitator for stirring a liquid. The agitators can be on the same rotation axis.

Abstract: An electrochemical cell is described that includes (a) a first electrode; (b) a second electrode; and (c) a channel contiguous with at least a portion of the first and the second electrodes. When a first liquid is contacted with the first electrode, a second liquid is contacted with the second electrode, and the first and the second liquids flow through the channel, a parallel laminar flow is established between the first and the second liquids. Electronic devices containing such electrochemical cells and methods for their use are also described.

Abstract: A fuel purification system includes a fuel cell stack and a fuel purification unit, such as a distillation unit. The fuel cell stack is adapted to provide heat to the fuel purification unit, and the fuel purification unit is adapted to provide a purified fuel to the fuel cell stack.

Abstract: In a power generation unit incorporated in a fuel cell system, a mixture fuel with a certain concentration is supplied to an anode, power is generated by electrochemical reaction between the anode and a cathode exposed to air, and a discharge liquid containing an unreacted mixture fuel is discharged from the anode. The power generation unit is connected to a fuel circulation path for circulating the discharge liquid to the anode. If a mixture fuel is low in pressure, a fuel supply unit supplies fuel to the fuel circulation path. The temperature of the power generation unit is controlled in accordance with the concentration or volume of the mixture fuel supplied to the anode.

Abstract: A fuel cell system includes a fuel cell which has an anode. A fuel supplying device circulates a supply of aqueous methanol solution to the anode in the fuel cell. The fuel supplying device includes an aqueous solution tank for storing the aqueous methanol solution. By moving aqueous methanol solution from the aqueous solution tank to a water tank, the amount of aqueous methanol solution which is in circulation at the time of start-up is made smaller than the amount for normal operation. The fuel cell system and a control method therefore are capable of shortening a time that is necessary for heating aqueous fuel solution to be supplied to the fuel cell to a predetermined temperature without reducing fuel utilization efficiency.

Abstract: A first detection line is set in a lower temperature range than a limit line representing an upper limit temperature of a motor allowed by an inverter and represents a reference motor temperature at a required output for fuel cells as a temperature criterion where a controller changes over the means for achieving the sufficient hydrogen stoichiometric ratio from recycling hydrogen with a circulation pump to increasing the hydrogen concentration. When the motor temperature reaches or exceeds the first detection line at the required output for the fuel cells, the controller prevents an increase in rotation speed of the motor and regulates the openings of a shutoff valve and a regulator to increase the concentration of hydrogen supplied from a hydrogen tank to the fuel cells and thereby increase the hydrogen supply pressure. This arrangement effectively prevents an increase of the motor temperature, while achieving the sufficient hydrogen stoichiometric ratio.

Abstract: A control apparatus for a fuel cell, including oxidizing gas supplying means for supplying oxidizing gas to a cathode via an oxidizing gas supply line; cathode-side gas pressure detecting means for detecting a gas pressure within the oxidizing gas supply line or the cathode; hydrogen supplying means for supplying hydrogen to an anode via a hydrogen supply line; target hydrogen partial pressure determining means for determining a hydrogen pressure among a gas pressure within the hydrogen supply line or the anode; hydrogen supply pressure calculating means for calculating a hydrogen supply pressure of hydrogen to be supplied to the fuel cell, based upon the target hydrogen partial pressure and the gas pressure detected by the cathode-side gas pressure detecting means; and hydrogen supply control means for supplying hydrogen from the hydrogen supplying means to the fuel cell at the hydrogen supply pressure, and the method thereof.

Abstract: A method of operating a fuel cell system includes characterizing the fuel or fuels being provided into the fuel cell system, characterizing the oxidizing gas or gases being provided into the fuel cell system, and calculating at least one of the steam:carbon ratio, fuel utilization and oxidizing gas utilization based on the step of characterization.

Abstract: A direct liquid feed fuel cell system includes fuel cells including an electrolyte membrane, a plurality of cathode electrodes formed on a first surface of the electrolyte membrane, and anode electrodes formed on a second part of the electrolyte membrane; and a high concentration fuel storage unit and a low concentration fuel storage unit which are separated from each other and store a liquid fuel to be supplied to the fuel cell. The liquid fuel in the low concentration fuel storage unit is supplied to the anode electrodes wherein the liquid fuel in the low concentration fuel storage unit is supplied to the anode electrodes when pressure is applied to the low concentration fuel storage unit, such as when the direct liquid feed fuel cell system having the low concentration fuel storage unit is mounted on an electronic device.

Abstract: A method for operating a direct methanol fuel cell is provided. The fuel cell includes a fuel cell main body having a fuel electrode and an air electrode disposed in opposing positions on either side of an electrolyte film. In this method, an aqueous methanol solution is supplied directly to the fuel electrode. A quantity of the aqueous methanol solution supplied is controlled in accordance with an electric current value drawn from the fuel cell main body so as to minimize a quantity of unused methanol within a discharge fluid discharged from the fuel electrode.

Abstract: A fuel cell system for power generation comprising a solid polymer type fuel cell having a solid polymer electrolyte membrane for separating an anode gas and a cathode gas, a resistor, an inverter, a switch for switching the inverter and the resister with respect to the fuel cell, the switch and the inverter, a supply conduit and discharge conduit for the anode gas and the cathode gas, and a supply vale and a discharge valve. When a molar ratio of the hydrogen contained in the anode gas to oxygen contained in the cathode gas becomes 2/1 or less at the time of the stop of the fuel cell, the supply valve for air is closed.

Abstract: A fuel cell comprises an anode comprising an anode catalyst, a cathode comprising a gas diffusion electrode and a cathode catalyst on the gas diffusion electrode, a microfluidic channel contiguous with the anode, and a liquid comprising fuel in the channel. The concentration of the fuel in the liquid is 0.05-0.5 M.

Abstract: A fuel cell supplies power to a load under nominal conditions. A method for using the fuel cell comprises at least one regeneration step of the performances of the fuel cell by temporarily lowering its temperature below the nominal operating temperature. The regeneration step, performed during a preset time, can be triggered periodically or when the voltage at the terminals of the fuel cell or the fuel cell temperature is lower than a threshold. The performances of the fuel cell, in particular its voltage, can thereby be maintained substantially constant during long periods of use.

Abstract: A method of measuring methanol vapor concentration on a real-time basis and a methanol vapor concentration measuring apparatus used in fuel cells. The method of measuring methanol vapor concentration involves using an absorption spectrometry technique, that is, after measuring intensities I0 and I1 of light of a laser before and after passing through a space filled with methanol vapor and into which light is irradiated, the methanol vapor concentration is calculated by substituting the intensities I0 and I1 into an equation defined as I1/I0=exp (K·L·C), where K represents the absorption coefficient, L represents the length of the space through which the laser passes, and C represents the methanol vapor concentration.

Abstract: Disclosed is a fuel cell system capable of stabilizing the power generation state of a fuel cell for a period of transition from a power generation stop state during an intermittent operation or the like to a usual operation. The fuel cell system supplies a fuel gas from a fuel supply source to a fuel cell to generate a power, and comprises output limit means for limiting the output of the fuel cell after shift from the power generation stop state of the fuel cell to a power generation state.

Abstract: A flow control assembly for use in a fuel cell system, comprising a sensor for sensing hydrogen concentration in one of anode exhaust leaving an anode side of the fuel cell system and a gas derived from the anode exhaust, and a fuel flow control assembly for controlling the flow of fuel to the anode side of the fuel cell system based on the hydrogen concentration sensed by the sensor.

Abstract: There are provided a power generation unit, a fuel tank, a line, a mixing tank, a fuel circulation unit which circulates a mixture fuel from the mixing tank to the mixing tank via the power generation unit and the line, a fuel supplier which supplies the fuel from the fuel tank to the mixing tank, an air supplier which supplies air to a cathode, a power adjustment unit which adjusts the current applied to the load in accordance with a generated power output, a fan which adjusts the temperature of the power generator, and a control unit which detects the concentration and volume of the mixture fuel and manipulates, on the basis of a detection result, the fuel circulation unit, the fuel supplier, the load of the power adjustment unit, the air supplier and the fan to control the concentration and volume of the mixture fuel.

Abstract: Fuel cell separation, fuel cell device, and electronic applied device technical field are provided. A fuel cell separator capable of making a fuel cell device compact and reducing variations in air supply amount to generating cells. Oscillating fans as fluid oxidant supplying means are respectively provided at openings of channels. The oscillating fans are individually driven to respectively supply air into the channels. The oscillating fans are included in a separator body of a separator. As compared with the case that the oscillating fans are provided separately from a fuel cell body having the separator as a component, the limitation to layout of the fuel cell body and various units for effecting stable electric power generation in the fuel cell body can be reduced, and the fuel cell device can be reduced in size.

Abstract: A fuel cell includes a fuel cell stack, a buffer, an actuator, and a control circuit. The control circuit controls the operation of the actuator according to a reference value of a reference volume of fuel disposed in the buffer. The fuel cell is operated by measuring a value corresponding to a volume of fuel disposed in the buffer, comparing the value with a reference value, and operating the actuator according to a result of the comparison.

Abstract: Control systems, sensors and methods for controlling the fuel concentration in a fuel cell or a fuel cell stack are provided. In certain examples, the control system may be configured to detect a performance degradation, and the fuel concentration provided to the fuel cell may be adjusted in response to detection of the performance degradation.

Abstract: In a fuel cell system (10), an anode exhaust gas discharge pipe (50) is full of hydrogen at the start of operation of a fuel cell (20). As time passes when the fuel cell (20) is operating, the concentration of impurities within the anode exhaust gas discharge pipe (50) increases. When the hydrogen concentration is less than a reference concentration for opening a valve, an upstream cut-off valve (61) closes and a downstream cut off valve (62) opens. As a result, the impurity concentration in the anode gas discharge pipe (50) quickly drops and is restored to the level that it was at the start of operation of the fuel cell (20). This sudden drop in the impurity concentration is caused by a pressure difference between the pressure in the anode exhaust gas pipe (50) and the pressure of the outside air, and the concentration gradient.

Abstract: The present invention relates to a direct oxidation fuel cell system including at least one electricity generating element including at least one membrane-electrode assembly which includes an anode and a cathode on opposite sides of a polymer electrolyte membrane, and a separator. The direct oxidation fuel cell generates electricity through an electrochemical reaction of a fuel and an oxidant. An oxidant supplier supplies the electricity generating element with the oxidant. A fuel supplier supplies the anode with a combination of fuel and hydrogen to provide improved power output.

Abstract: Fuel concentration near a power generator of a DMFC is adjusted by decreasing current taken from the DMFC when the concentration near the power generator of the DMFC is higher than an optimum value and increasing the current taken from the DMFC when the concentration near the power generator of the DMFC is lower than the optimum value. Since the fuel does not come into direct contact with the power generator in the DMFC in a portion from a cartridge to the power generator in the DMFC, drying of the fuel is suppressed. By providing an auxiliary tank capable of storing fuel, concentration of methanol supplied near the power generator of the DMFC is lowered upon activation after long-time storage.

Abstract: A method of operating a fuel cell (1) in which a gaseous supply stream (5) comprising a reactive species is delivered to an electrode (2) where the reactive species is consumed in an electrochemical reaction to produce an exhaust stream (7, 8) which is depleted in reactive species, which method comprises: a) assessing the concentration of reactive species in the exhaust stream (7, 8); b) relating the concentration of reactive species in the exhaust stream (7, 9) to a maximum current that may be drawn from the fuel cell (1) without redox damage of the electrode; and c) adjusting the way in which the fuel cell (1) is operated in order to optimize efficiency without redox damage of the electrode (2).

Abstract: A direct oxidation fuel cell (DOFC) system, comprises at least one fuel cell assembly including a cathode and an anode with an electrolyte positioned therebetween; a source of liquid fuel in fluid communication with an inlet of the anode; an oxidant supply in fluid communication with an inlet of the cathode; a liquid/gas (L/G) separator in fluid communication with outlets of the anode and cathode for: (1) receiving unreacted fuel and liquid and gaseous products, and (2) supplying a solution of fuel and liquid product to the anode inlet; and a control system for measuring the amount of liquid product and controlling oxidant stoichiometry of the system operation in response to the measured amount of liquid product. Alternatively, the control system controls the concentration of the liquid fuel in the solution supplied to the anode inlet, based upon the system operating temperature or output power.

Abstract: A fuel cell system (50) includes pressure obtaining means (4) for obtaining the pressure in a hydrogen system (anode (1b)) of a fuel cell (1), pressure estimation means (10) for estimating the hydrogen partial pressure in the hydrogen system. Further, the fuel cell system (50) includes impurity concentration estimation means (10) for estimating the impurity concentration in the hydrogen system. That is, the impurity concentration estimation means (10) estimates the impurity concentration taking the present state of the hydrogen system into consideration. Thus, the impurity concentration estimation means (10) accurately estimates the impurity concentration in the hydrogen system of the fuel cell (1).

Abstract: A fuel cell system which includes: a fuel cell fed with a reaction gas for generating power; an output detection unit which detects output current and voltage of the fuel cell; a storage unit which stores a standard current-voltage characteristic of the fuel cell, from which a standard voltage of the fuel cell at an output current thereof is obtainable; and a gas feed mismatch detection unit which detects a gas feed mismatch of the reaction gas, based on a comparison between the detected output voltage of the fuel cell and the standard voltage at the detected output current, obtained from the standard current-voltage characteristic stored.

Abstract: A high-precision gas leak judgment comparable to that when the fuel cell is operating normally is achieved even when a fuel cell is restarted. A gas leak judgment unit (for example ECU 13) for judging gas leak in a closed space formed in a fuel gas system refers to a gas leak judgment value based on pressure change in the closed space detected by a pressure sensor to judge gas leak and, in addition, varies the fuel gas leak judgment level in response to nitrogen concentration in a fuel electrode. The varying of gas leak judgment level in response to the nitrogen concentration takes into account a temporary rise in the nitrogen concentration in the fuel electrode that occurs when a fuel cell stack is restarted and, in this case, it is preferable that the gas judgment value be altered in response to the nitrogen concentration.

Abstract: A fuel cell system includes a fuel cell including at least one unit cell having an anode, an anode-side flow channel for supplying a fuel to the anode, a cathode, and a cathode-side flow channel for supplying an oxidant to the cathode. The fuel cell system further includes a gas-liquid separator for catalytically purifying the effluent from the anode and the effluent from the cathode to collect liquid. The gas-liquid separator is connected to an anode-side discharge path for the effluent and a cathode-side discharge path for the effluent, which are in fluid communication with a fuel outlet of the anode-side flow channel and an oxidant outlet of the cathode-side flow channel, respectively.

Abstract: A direct methanol fuel cell system includes a fuel cell main body including at least one membrane-electrode assembly having an electrolyte membrane, and an anode and a cathode positioned on opposite sides of the electrolyte membrane; a fuel-supplying unit feeding a mixing tank with high concentration fuel; the mixing tank mixing and storing the fuel fed from the fuel-supplying unit and an outlet stream discharged from the fuel cell main body; a fuel feeder supplying mixed fuel stored in the mixing tank to the fuel cell main body; and a controller controlling the fuel-supplying unit to stop operating in response to a stop request signal, and controlling the fuel feeder to operate to circulate the mixed fuel via the anode of the fuel cell main body until a fuel concentration of the mixed fuel is less than or equal to a reference concentration.