Abstract: In a method for regulating a fuel cell stack (1), a current-voltage characteristic of the fuel cell stack is detected and evaluated to determine an operating point of the fuel cell stack, wherein a current-voltage characteristic of the fuel cell stack (1) is detected at time intervals in operation whose gradient has a minimum, a characteristic value (Rmin) for the minimum of the gradient is respectively determined from the detected current-voltage characteristic and a desired value for the operating point is determined by addition of a predefined offset value (Roffset) to the characteristic value, and wherein the fuel cell stack (1) is regulated by the desired value determined in this manner.

Abstract: The present invention relates to a fuel cell system and a control method therefor. An aspect of the present invention provides a fuel cell system comprising: a fuel cell stack; a memory unit in which a plurality of current-voltage curves, which are determined according to operation conditions of the fuel cell stack, are stored; a measurement unit for detecting an operation condition of the fuel cell stack; and a control unit for calling a current-voltage curve which satisfies the operation condition of the fuel cell stack, detected by the measurement unit, and predicting the performance of the fuel cell stack according to the called current-voltage curve.

Abstract: In a fuel cell system, each of an inlet sealing valve and an outlet integration valve is provided with a valve seat including a valve hole and a seat surface formed on a circumferential edge of the valve hole, a valve element formed, on its outer periphery, with a seal surface corresponding to the seat surface, and a motor to move the valve element away from the valve seat upon receipt of electric power supplied from outside. The valve seat is provided with a seal member to seal between the valve element and the valve seat during non-operation of the motor. In an inlet-side bypass passage connected to an air supply passage by detouring around the inlet sealing valve, there are arranged an inlet-side bypass passage and an inlet bypass valve.

Abstract: A fuel cell system is disclosed, which includes an anode recirculation loop comprising a fuel cell stack for generating power, a flowmeter for measuring a fuel flow rate of a fuel provided into the anode recirculation loop, a current measuring device for measuring a current drawn from the fuel cell stack, a recycle ratio measuring device for measuring a recycle ratio in the anode recirculation loop, and a processor for estimating a fuel utilization of the fuel cell stack based on the measured fuel flow rate, the measured current and the measured recycle ratio. Methods for operating the fuel cell system are also disclosed.

Abstract: Disclosed are modular microbial fuel cell (MFC) devices, systems and methods for treating wastewater and generating electrical energy through a bioelectrochemical waste-to-energy conversion process. In some aspects, a modular MFC system includes a wastewater pretreatment system to receive and pre-treat raw wastewater for feeding pre-treated wastewater for bioelectrochemical processing; one or more modular MFC devices to bioelectrochemically process the pre-treated wastewater by concurrently generating electrical energy and digesting organic contaminants and particulates in the wastewater to yield treated, cleaner water; and a water collection module to receive the treated water from the one or more modular MFC devices and store the treated water and/or route the treated water from the system.

Abstract: Improved methods are disclosed for shutting down and storing a fuel cell system, particularly for below freezing temperature conditions. The methods comprise stopping power production from the fuel cell stack, monitoring its temperature, and repeatedly performing a predetermined warming operation if the stack temperature falls to a normal threshold temperature. In the improved methods, either an initial threshold temperature and/or an initial warming operation are used that differ from the respective normal threshold temperature and the predetermined warming operation.

Abstract: Provided are an inspection apparatus and method capable of accurately detecting a defective membrane electrode assembly based on the rate of deterioration of carbon forming an electrode catalyst layer or the like of the assembly.

Abstract: A fuel cell system includes a fuel cell stack and a controller. The fuel cell stack includes a catalyst and a stack voltage. The controller increases efficiency of the fuel cell stack by minimizing or removing an accumulation of oxides on the catalyst during a low-power operating mode of the fuel cell system. The controller executes a method for dynamically controlling the stack voltage during a detected low-power operating mode. The method includes commanding low-voltage/high-power pulses to the fuel cell stack via the controller at a magnitude and frequency sufficient for minimizing or removing the oxides. The system may include a direct current-direct current (DC-DC) boost converter, with the controller programmed to command the power pulses from the DC-DC boost converter. Or, the controller may be configured to command the power pulses by controlling a feed rate of the oxygen and/or the hydrogen.

Abstract: A fuel cell system configured to generate an electric power by supplying an anode gas and a cathode gas to a fuel cell includes: a connection line configured to connect the fuel cell to an electric load; a converter connected to the connection line and a battery, the converter being configured to adjust a voltage of the connection line; a target output current calculating unit configured to calculate a target output current of the fuel cell in accordance with a load of the electric load; a converter control unit configured to carry out a switching control for the converter in accordance with the target output current; and a flow rate control unit configured to control a flow rate of the cathode gas to be supplied to the fuel cell in accordance with the target output current.

Abstract: A method and system for controlling air flow is arranged to reduce power consumption of an air blower or an air compressor by controlling air flow, enhance stack performance by preventing stack dry-out that is more likely to occur in a low-flow range, and improve durability of the stack by decreasing frequency of exposure to high voltages.

Abstract: The disclosure provides a fuel device for an automobile, an automobile with the fuel cell device and a method for operating the fuel cell device. The fuel cell device comprises a first pipe, a second pipe, and a pressure regulator. The first pipe connects a gas tank to a fuel cell. The second pipe connects the fuel cell with an open end of the second pipe. The fuel cell is arranged to be driven by evaporated liquefied gas contained the gas tank. The pressure regulator is arranged to control the evaporation of the liquefied gas.

Abstract: A fuel cell cooling system includes an air temperature estimating unit, an air temperature sensor and an abnormality determining unit. The air temperature sensor senses an air detection temperature of the air that flows out of the air cooler and is supplied to the fuel cell. The air temperature estimating unit estimates an air estimation temperature of the air, based on a temperature of a refrigerant flowing into the air cooler, a power supply quantity of a power supplied to the circulation pump, a temperature of the air flowing into the air cooler and a flow volume of the air. The abnormality determining unit determines that a circulation flow volume of the refrigerant is in an abnormal state when the air detection temperature is higher than the air estimation temperature by a value greater than or equal to a predetermined value.

Abstract: A formed substrate assembly includes an air flow form plate, a fuel flow form plate, and an anode. The fuel flow form plate is positioned over the air flow form plate. The fuel flow form plate partially defines a plurality of first channels. The fuel flow form plate also defines a plurality of second channels. The plurality of second channels defines a plurality of apertures, where a portion of the apertures extend from the plurality of second channels to the plurality of first channels. The anode is positioned over the fuel flow form plate. The anode partially defines the plurality of first channels such that the fuel flow form plate and the anode define the plurality of first channels. The portion of the plurality of apertures is configured to channel a flow of fuel from the plurality of second channels to the plurality of first channels.

Abstract: Systems and methods for testing a fuel cell stack include a vacuum source, a test head including at least one isolated vacuum plenum configured to be positioned in fluid communication with a first portion of the fuel cell stack, the isolated vacuum plenum in fluid communication with the vacuum source, and a detector in fluid communication with the at least one isolated vacuum plenum for detecting the presence of a particular constituent of a fluid provided in a second portion of the fuel cell stack, where the second portion of the fuel cell stack is separated from the first portion of the fuel cell stack by at least one of an electrolyte and a fuel cell seal.

Abstract: Systems, methods, and other embodiments associated with fuel cell power management. According to one embodiment, a fuel cell stack includes a plurality of fuel cells producing electric potentials. An electric potential of a fuel cell is measured as a fuel cell voltage. The fuel cell stack further includes a plurality of connection points including a ground, a first connection point, and a second connection point. The first connection point draws a first voltage based on combined fuel cell voltages of a first set of fuel cells of the plurality of fuel cells. The second connection point draws a second voltage based on the combined fuel cell voltages of a second set of fuel cells of the plurality of fuel cells.

Abstract: A fuel cell system is disclosed, which includes a fuel cell stack coupled to a load for providing power, a gas delivery system coupled to the fuel cell stack for providing fuel and oxygen to the fuel cell stack and a control system. The control system includes a forward controller for generating a desired control instruction signal based on a command from the load, and a correction controller for generating a control correction signal to avoid violating operational constraints of the fuel cell stack based on at least one measured signal from the fuel cell system. The control system generates a control signal based on the desired control instruction signal and the control correction signal, and controls the gas delivery system based on the generated control signal to ensure the fuel cell stack is operated within safe operating limits. A method for controlling the fuel cell system is also disclosed.

Abstract: A fuel cell system supplies anode gas and cathode gas to a fuel cell and generates electric power in accordance with a load. The fuel cell system configured to include a cathode gas control unit controls a pressure of the cathode gas on the basis of the load, an anode gas control unit configured to cause a pressure of the anode gas to pulsate on the basis of the pressure of the cathode gas and a pulsation amplitude. The pulsation amplitude is determined on the basis of an operating condition of the fuel cell. The fuel cell system includes an anode gas partial pressure maintenance control unit configured to increase the pressure of the anode gas in accordance with a condition of an impurity within the fuel cell. The cathode gas control unit configured to make the pressure of the cathode gas higher when a pressure difference between the pressure of the anode gas and the pressure of the cathode gas is large than when the pressure difference is small.

Abstract: A method for controlling a fuel cell vehicle includes acquiring a state data, deriving a mathematical voltage model by substituting the acquired state data into a voltage calculation formula, measuring a voltage of a fuel cell, approximating a mathematical voltage model to a measurement voltage and deriving the reaction area data when the mathematical voltage model approximates the measurement voltage, and controlling the system of the fuel cell vehicle based on the derived reaction area data to eliminate or prevent an over-humidification situation of the fuel cell.

Abstract: The fuel cell unit comprises a fuel cell including a cell stack with a plurality of stacked cells; a cell monitor which monitors one or more of the plurality of stacked cells; a control device connected with the cell monitor via a communication cable; a first case which places the fuel cell therein; and a second case which places the control device therein and fixed to an upper surface of the first case. The cell monitor includes a connector portion protruded from the first case and provided with a connection connector which is connected with a communication connector of the communication cable. The second case includes an insertion space for receiving the connector portion when the second case is fixed to the first case and further includes a connector opening in a surface opposed to the connection connector when the connector portion is inserted in the insertion space.

Abstract: A method of cleaning power cells in an array of power cells, comprising coupling at least one first power cell to second power cells in an array of power cells and causing the second power cells to drive the at least one first power cell with a voltage to clean catalyst on the at least one first power cell.

Abstract: A fuel cell power controller tracks load current and fuel cell output voltage, and alerts on excessive fuel cell ramp rate, so another power source can supplement the fuel cell and/or the load can be reduced. A power engineering process makes efficient use of available fuel cell power by ramping up power flow rapidly when power is available, while respecting the ramp rate and other power limitations of the fuel cell and safety limitations of the load. Power flow decreases after an alert indicating an electrical output limitation of the fuel cell. Permitted power flow increases in response to a power demand increase (actual or requested) from the load in the absence of the alert. Power flow may increase or decrease in a fixed amount, a proportional amount, or per a sequence. A power controller relay may trip open on a low fuel cell output voltage or high load current.

Abstract: An AC component ?I addition unit of a diagnostic device superimposes an alternating current on an output current of a fuel cell. A Zn calculation unit calculates a cell impedance with respect to the alternating current with regard to any of a plurality of cells. A diagnosis unit diagnoses that any cell is subjected to hydrogen deficiency when an absolute value of the cell impedance exceeds (absolute value of a reference impedance+a predetermined value ?). It is diagnosed that any cell is subjected to oxygen deficiency when the absolute value of the cell impedance is smaller than (absolute value of the reference impedance?a predetermined value ?).

Abstract: A fuel cell system comprising: an acquirer that acquires a total value of cell voltages of two or more cells included in a fuel cell; and a determiner that determines, when the total value is a first voltage value, abnormal power generation in which power generation by at least a part of the two or more cells is abnormal, that determines, when the total value is a second voltage value higher than the first voltage value, normal power generation in which power generation by the two or more cells is normal and that determines, when the total value is a third voltage value higher than the first voltage value but lower than the second voltage value, the normal power generation if a cathode gas is deficient or the abnormal power generation if the cathode gas is not deficient.

Abstract: A method for determining a spatial distribution (Rcx,yf) of a parameter of interest (Rc) representative of a contact resistance between a bipolar plate and an adjacent electrode of an electrochemical cell, in which a spatial distribution (Rcx,yf) of the parameter of interest (Rc) is determined depending on the spatial distribution (Qx,ye) of a second thermal quantity (Qc) estimated beforehand from the spatial distribution (Tx,yc) of a set-point temperature (Tc) and from the spatial distribution (Dx,yr) of a first thermal quantity (Dr).

Abstract: An apparatus for generating injection current for a fuel cell stack includes a first converter configured to convert direct current of a voltage corresponding to a high voltage battery, into direct current of a predetermined voltage; a second converter configured to convert the converted direct current into alternating current; a filter configured to filter a signal of a predetermined frequency band from the converted alternating current; and a control unit configured to perform a feedback control to allow the filtered alternating current to be injected without being distorted when injecting the filtered alternating current into the fuel cell stack.

Abstract: A method for determining a spatial distribution (Rcx,yf) of a parameter of interest (Rc) representative of a contact resistance between a bipolar plate and an adjacent electrode of an electrochemical cell, in which a spatial distribution (Rcx,yf) of the parameter of interest (Rc) is determined depending on the spatial distribution (Qx,ye) of a second thermal quantity (Qc) estimated beforehand from the spatial distribution (Tx,yc) of a set-point temperature (Tc) and from the spatial distribution (Dx,yr) of a first thermal quantity (Dr).

Abstract: The present disclosure is directed towards a method and a system for monitoring the performance of an electrochemical cell stack. Monitoring can be performed remotely by measuring the voltage across the stack, and comparing the measured values to predetermined reference values to determine the condition of the stack. Monitoring of the stack voltage enables detection of performance decay, which in turn enables preemptive repair of the stack prior to catastrophic failure.

Abstract: An operation method of a fuel cell system includes providing a turbo pump to supply an oxidant gas to a fuel cell to generate power through a reaction between a fuel gas and the oxidant gas. A branch valve to regulate a flow rate of the oxidant gas which flows through a branch passage that connects an oxidant gas supply passage and an oxidant off-gas discharge passage is provided. The turbo pump and the branch valve are controlled to regulate a flow rate of the oxidant gas to be supplied to the fuel cell in an extremely low power generation mode in which an extremely low generation power is requested. The extremely low generation power is less than or equal to a predetermined generation power corresponding to a minimum flow rate of the oxidant gas that is supplied by the turbo pump.

Abstract: As an activation time power generation mode of a fuel cell system, a control device executes: a first step of determining whether or not hydrogen is present in an anode gas flow path; a second step of bringing a contactor to a connected state if hydrogen is detected in the first step as being present in the anode gas flow path; a third step of supplying air to a cathode through a cathode gas flow path after the second step has been executed; and a fourth step of, if a voltage of the fuel cell stack detected by a voltage detection device reaches a predetermined voltage, connecting an electrical load to the fuel cell stack, and performing electric power generation of the fuel cell stack while maintaining the voltage at or below the predetermined voltage.

Abstract: A method for controlling startup of a fuel cell vehicle is provided. The disclosed method includes detecting generation of a startup command from a vehicle and supplying hydrogen to a fuel cell by opening a hydrogen valve. Additionally, the method includes detecting whether a fuel cell voltage has increased after supply of hydrogen, and a first startup of consuming generated electric power of the fuel cell through connection of a load device to the fuel cell, supplying air to the fuel cell through opening an air valve and adjusting the fuel cell voltage to be maintained at a predetermined level or less through adjustment of a bus stage voltage of a power converter when the controller determines that the fuel cell voltage has increased after supply of hydrogen.

Abstract: A concentration of a fuel supplied to a fuel cell and a heat exchange rate of a heat exchanger are controlled simultaneously in order to maintain a temperature of fuel cell stack and a diluted fuel concentration that is supplied to the fuel cell stack in a target level. Further, by appropriately responding to an exterior temperature changes or unexpected fuel cell performance changes, it is possible to improve a system efficiency and stability of fuel cell operation and to regulate the fuel concentration quickly and accurately compared to a prior sensor-less concentration controller.

Abstract: A fuel cell system and a method for controlling the fuel cell system are provided. The method includes detecting an output characteristic value of the fuel cell system and controlling the fuel cell system to respectively operate in at least two of a first mode, a second mode and a third mode at different time points according to the detected output characteristic value. Accordingly, the fuel cell system is capable of stably generating electric power, and is adapted to different operation environments.

Abstract: A fuel cell stack assembly has a plurality of cells in a stack configuration. Each cell comprises a membrane-electrode assembly disposed between an anode flow plate and a cathode flow plate. A current collector plate is disposed at each end of the stack and a compression assembly maintains the stack under compression. At least one of the current collector plates is formed as a printed circuit board having a first face disposed against a cathode flow plate or an anode flow plate of an outermost cell in the stack and a second face opposite the first face. The first face includes an electrically conductive layer disposed on a substrate of the printed circuit board to serve as a stack current collector electrode. Electrical components such as temperature sensors can be mounted on the printed circuit board such that they lie in or adjacent to a flow channel extending along an adjacent face of the anode or cathode flow plate.

Abstract: A fuel cell system, which includes a fuel cell for generating electric power and which discharges externally water remaining in the fuel cell by supplying a gas to the fuel cell, includes discharge amount estimating means, for estimating, based on the state of the fuel cell (the amount of residual water or an inclination angle), the amount of water to be discharged from the fuel cell.

Abstract: A battery state determination device, which determines a micro-short-circuiting tendency state, includes an impedance meter that applies an AC voltage or an AC current of a measurement frequency to a rechargeable battery, which is subject to determination, and measures complex impedance. The device further includes a detector that detects an absolute value of an imaginary axis component of the complex impedance. The device further includes a determiner that compares the absolute value of the imaginary axis component detected by the detector with a lower limit threshold value. The lower limit threshold value is set based on a measurement result of the absolute value of the imaginary axis component of the rechargeable battery in the micro-short-circuiting tendency state. When the absolute value of the imaginary axis component is smaller than the lower limit threshold value, the determiner determines that the rechargeable battery is in the micro-short-circuiting tendency state.

Abstract: An air compressor control method for a fuel cell vehicle is provided. The method includes sensing variation information of a rotation speed of an air compressor motor and sensing a state of charge (SOC) of a high voltage battery by the fuel cell controller when the rotation speed of the air compressor motor is reduced. An allowable current from regenerative braking of an air compressor is derived using current consumption of an electric or electronic sub-assembly for a fuel cell vehicle in response to determining that the SOC exceeds a predetermined level of the SOC. The air compressor motor is then operated based on the allowable current from regenerative braking by an air compressor controller.

Abstract: A state determination device for a fuel cell for generating power upon receiving the supply of anode gas and cathode gas, comprising: an internal impedance measurement unit configured to measure an internal impedance of the fuel cell on the basis of an alternating-current signal of a predetermined frequency output from the fuel cell; and an anode reaction resistance estimation/calculation unit configured to calculate an estimation value of a reaction resistance of an anode electrode of the fuel cell on the basis of a measurement value of the internal impedance, wherein: the predetermined frequency is selected such that a difference between the estimation value of the reaction resistance of the anode electrode during hydrogen starvation and the estimation value of the reaction resistance of the anode electrode during oxygen starvation is not smaller than a predetermined value.

Abstract: A fuel cell stack 5 adapted for an electrochemical reaction of a fuel gas to generate an electric power is provided with a working point measuring section 51 for measuring a generation voltage and a generation current of the fuel cell stack 5, and connected to a controller 7 including an output characteristic map memory 72 for storing output characteristics of the fuel cell stack 5, and a potential output power estimator 71 for estimating a potential output power of the fuel cell stack 5 based on a combination of a current generation voltage VO and a current generation current IO measured by the working point measuring section 51 and pieces of information stored in the output characteristic map memory 72.

Abstract: A method of controlling humidification of a fuel cell includes the steps of measuring impedance of the fuel cell, and adjusting humidification quantity of the fuel cell based on an imaginary axis value Xi and a real axis value Xr on a complex number plane of the measured impedance after the measurement step. In the measurement step, impedance is measured based on supply of alternating current having one frequency of 10 Hz or less during power generation of the fuel cell.

Abstract: An integrated DC/DC converter includes a first DC/DC converter, a second DC/DC converter, a first voltage sensor, a second voltage sensor, a first current sensor, a second current sensor, a third current sensor, and a controller. The first DC/DC converter has an input end and an output end. The input end of the first DC/DC converter is to be electrically connected to an output end of an electrochemical energy storage apparatus. The output end of the first DC/DC converter is to be electrically connected to an input end of an electrical load. The second DC/DC converter connects the first DC/DC converter in parallel.

Abstract: An apparatus and a method for measuring the internal ohmic resistance of a fuel cell system, in which the resistance can be easily measured through a current interruption method even while the fuel cell system is operated. An interrupter and an external energy consumption device are connected in parallel to each other between a fuel cell and a main energy consumption device such that current to the external energy consumption device is applied and interrupted by switching the interrupter on/off even while the fuel cell system is maintained in operation as is, thereby making it possible to easily measure the internal ohmic resistance of the fuel cell.

Abstract: A fuel cell system that includes a fuel cell that generates electricity through an electrochemical reaction between a fuel gas and an oxidant gas, and a control portion that determines whether there is leakage of the fuel gas. The control portion has start means for starting the fuel cell by raising the voltage of the fuel cell from a starting voltage to an operation voltage that is lower than an open-circuit voltage, and leakage determination means for determining whether there is leakage of the fuel gas before the voltage of the fuel cell reaches the operation voltage when the fuel cell is started.

Abstract: A voltage synchronization method and system are provided. The system includes a main controller that is configured to determine whether voltage synchronization is possible. When the voltage synchronization is determined to be possible, the main controller is configured to transmit a voltage synchronization command to a plurality of auxiliary controllers. The plurality of auxiliary controllers are configured to adjust sensed voltages based on an output voltage of a fuel cell stack when the transmitted voltage synchronization command is received.

Abstract: A method for activating a stack of a fuel cell is provided. The method includes supplying oxygen and hydrogen to the stack after starting an activation process to change the stack to an open circuit voltage (OCV) state and terminating the supply. Adjacent cells of the stack are electrically connected by a cell voltage sensing terminal board and the adjacent cells are shorted to allow a cell voltage to be 0V. Additionally, oxygen and hydrogen are resupplied to the stack and predetermined current density is applied for a predetermined time is executed. The voltage is again decreased to be 0V by applying current density exceeding the predetermined current density for a time exceeding the predetermined time through the open circuit voltage state to remove oxygen remaining in the stack. Oxygen and hydrogen are resupplied after a silent period has elapsed for a predetermined time after removing the remaining oxygen.

Abstract: An electric vehicle includes a controller configured to receive sensor feedback from a high voltage storage device and from a low voltage storage device, compare the sensor feedback to operating limits of the respective high and low voltage storage device, determine, based on the comparison a total charging current to the high voltage storage device and to the low voltage storage device and a power split factor of the total charging current to the high voltage device and to the low voltage device, and regulate the total power to the low voltage storage device and the high voltage storage device based on the determination.

Abstract: A system and method for emergency starting of a fuel cell vehicle is provided. In particular, a high-voltage converter, a balance of power (BOP), and a controller are included in the system. The high-voltage converter is configured such that one side thereof is connected to a high-voltage battery via a battery switch and the other side thereof is connected in parallel to a plurality of fuel cells. The BOP is connected in parallel to the high-voltage converter and the fuel cells. The controller is configured to control the power supplied from the high-voltage battery to the BOP without conversion by connecting the battery switch upon the failure of the high-voltage converter or high-voltage battery.

Abstract: A method of cleaning power cells in an array of power cells, comprising coupling at least one first power cell to second power cells in an array of power cells and causing the second power cells to drive the at least one first power cell with a voltage to clean catalyst on the at least one first power cell.

Abstract: A fuel cell system includes an auxiliary machine to be connected to a fuel cell, warm-up power control means for controlling generated power of the fuel cell by adjusting power supplied to the auxiliary machine during the warm-up of the fuel cell, and IV characteristic estimation means for temporarily reducing the power supplied to the auxiliary machine and estimating an IV characteristic of the fuel cell on the basis of at least two pairs of current values and voltage values at that time during the warm-up of the fuel cell.

Abstract: A water-based bonding primer composition and a method of applying the same onto a metallic surface prior to adhesive bonding. The bonding primer composition is a water-based dispersion containing water, one or more epoxy resins, one or more curing agents, a silane compound, a low amount of propylene carbonate (PC), and optional additives. The bonding primer composition can form substantially smooth films by spraying, and at the same time, meet environmental regulations and provide high bonding performance.

Abstract: A method of improving the electrical performance of an operating fuel cell catalyst-containing cathode in a fuel cell connected to an electrical load by: reducing the flow of air to the cathode; disconnecting the load from the fuel cell; connecting a potentiostat to the fuel cell; cycling an applied voltage, current, or power to the fuel cell one or more times; disconnecting the potentiostat from the fuel cell; reconnecting the load to the fuel cell; and resuming the flow of air to the cathode.