A system and method for controlling a discharge of residual water remaining in a fuel cell stack after an operation of a fuel cell is ended is provided. The method includes determining whether a preset temperature condition is satisfied, determining whether a preset time condition is satisfied when the temperature condition is satisfied, and discharging residual water in a fuel cell stack while a vehicle travels when the temperature condition and the time condition are satisfied.

An apparatus for estimating an amount of condensed water in an anode of a fuel cell system includes: an initial anode water vapor amount calculation unit to calculate an initial amount of water vapor in the anode of a fuel cell upon startup, an anode diffusion amount calculation unit to calculate an amount of H.sub.2O diffused from a cathode to the anode, a purge amount calculation unit to calculate an amount of water vapor discharged upon gas purging in the anode, a recirculation amount calculation unit to calculate the amount of water vapor recirculated to the anode, and a condensed water amount determination and water level estimation unit to calculate the actual amount of water vapor in the anode based on values calculated using these units and to calculate the amount of condensed water in a water trap.

A fuel cell vehicle includes a fuel cell, a gas supply unit, a friction brake system, a drive motor, an electric storage device, and a control unit configured to execute control of obtaining requested braking force with use of friction braking force and regenerative braking force and control of performing a scavenging process. When the fuel cell vehicle is in braking with the friction braking force and the regenerative braking force, the control unit is configured to determine whether or not a scavenging preparation condition is satisfied with use of the amount of stagnant water stagnating in the fuel cell, execute a responsiveness enhancement process when the scavenging preparation condition is executed, and execute a scavenging process when the responsiveness enhancement process is completed, and the amount of the stagnant water reaches a reference value.

A condensate water storage device including a storage container defining a storage space to store condensate water, and having a discharge hole through which the condensate water is discharged to the outside, a valve unit to selectively open and close the discharge hole, a connection cable connected to the valve unit, and a winding unit connected to the connection cable to selectively wind the connection cable and manipulate an operation of the valve unit, thereby selectively discharging the condensate water, which is produced from a fuel cell.

The present disclosure provides a fuel cell stack, a fuel cell system and a method for controlling a fuel cell stack, which can reduce obstruction of reactive gas fluid channels caused by freezing of retained water, while allowing size to be reduced. The fuel cell stack of the disclosure comprises water storage units that are formed between every two adjacent fuel cell unit cells, surrounded by the adjacent separators, the wall members and the gaskets, and that communicate with the reactive gas discharge manifold via the gaps of the wall members. The fuel cell system of the disclosure controls either or both the valve and compressor in a reactive gas supply channel and/or the valve in a reactive gas discharge channel, to cause liquid water retained in the water storage units to be discharged out of the fuel cell stack. The controlling method of the disclosure includes reducing the pressure in and scavenging the interior of the reactive gas discharge manifold, to cause the liquid water that has been discharged into the reactive gas discharge manifold to be discharged out of the fuel cell stack.

An electrochemical cell utilizes an air flow device that draws air through the cell from a scrubber that may be removed while the system is operating. The negative pressure generated by the air flow device allows ambient air to enter the cell housing when the scrubber is removed, thereby enabling continued operation without the scrubber. A moisture management system passes outflow air from the cell through a humidity exchange module that transfers moisture to the air inflow, thereby increasing the humidity of the air inflow. A recirculation feature comprising a valve allow a controller to recirculate at least a portion of the outflow air back into the inflow air. The system may comprise an inflow bypass conduit and valve that allows the humidified inflow air to pass into the cell inlet without passing through the scrubber. The scrubber may contain reversible or irreversible scrubber media.

A method for purging the hydrogen feed anode circuit of a fuel cell, whereby hydrogen is fed at a nominal pressure to the inlet of the cell, characterized in that at predetermined periodicity the following steps are repeated: instruction is given to open the hydrogen purge valve arranged on the outlet of the anode circuit; the pressure of hydrogen is measured at the inlet to the anode circuit of the cell, and the measured value is compared with a predetermined threshold pressure value; and the purge valve is closed when the measured pressure is equal to or lower than the predetermined threshold pressure value.

The invention relates to a method for removing water from a fuel cell system (1) comprising a fuel cell stack (2) having an anode portion (3) and a cathode portion (4), a purge valve (5) downstream of the anode portion (3) for controlling a purge pressure in the anode portion (3), and a back pressure valve (6) downstream of the cathode portion (4) for controlling a back pressure in the cathode portion (4), comprising the steps: increasing the purge pressure in the anode portion (3) to a predefined purge pressure setpoint (AP1) with the purge valve (5) closed, increasing the back pressure in the cathode portion (4) to a predefined back pressure setpoint (KP1) with the back pressure valve (6) closed, and subsequently reducing the increased purge pressure as well as the increased back pressure in pulses by opening the purge valve (5) and the back pressure valve (6). Furthermore, the invention relates to a fuel cell system (1) and a computer program product (10) for carrying out a method according to the invention, as well as a storage means comprising a computer program product (10) stored thereon.

A fuel cell system includes a supply valve for supplying an anode gas into an anode system, a purge valve for discharging an off-gas from the anode system, a pressure detecting portion configured to estimate or measures a pressure inside the anode system, a supply valve control portion configured to control an open/close operation of the supply valve based on a load of the fuel cell, a purge flow rate estimating portion configured to estimate a purge flow rate of the off-gas discharged from the anode system through the purge valve based on a pressure decrease inside the anode system in a supply valve close state, and a purge valve control portion configured to open the purge valve in synchronization with the supply valve close state.

A reforming element for a molten carbonate fuel cell stack and corresponding methods are provided that can reduce or minimize temperature differences within the fuel cell stack when operating the fuel cell stack with enhanced CO.sub.2 utilization. The reforming element can include at least one surface with a reforming catalyst deposited on the surface. A difference between the minimum and maximum reforming catalyst density and/or activity on a first portion of the at least one surface can be 20% to 75%, with the highest catalyst densities and/or activities being in proximity to the side of the fuel cell stack corresponding to at least one of the anode inlet and the cathode inlet.