A fuel cell exhaust device includes a pipe having one side open and the other side closed, a water tank having one side open and the other side closed, a reformer exhaust pipe communicating with the pipe between one side and the other side of the pipe, a stack exhaust pipe which is spaced apart from the reformer exhaust pipe and communicates with the pipe between one side and the other side of the pipe, a drain pipe positioned adjacent to the reformer exhaust pipe or the stack exhaust pipe and disposed on an outer circumferential surface of the water tank to communicate with the inside of the water tank, and a hole defined on the closed other side of the pipe and spaced apart from the closed other side of the water tank.

A power system for an unmanned surface vehicle includes a fuel cell including a fuel cell stack, where the fuel cell stack includes a fuel inlet. The power system also includes a fuel storage including at least one fuel-storage module fluidly connected to the fuel inlet of the fuel cell stack. The fuel-storage module is a source of energy for the fuel cell. The power system also includes a fuel and thermal management system fluidly connected to the fuel inlet of the fuel cell stack. The fuel and thermal management system includes a heat exchanger in thermal communication with the fuel cell stack for removing waste heat produced by the fuel cell stack during operation. The fuel and thermal management system also includes a flow valve, a pressure regulator, and a conduit.

In a case that activation is implemented on a fuel cell, a variable voltage is applied to a membrane electrode assembly while a first gas is supplied to an anode and a second gas is supplied to a cathode. Thereafter, while a constant voltage is applied to the membrane electrode assembly, liquid water is generated at the anode or the cathode. Alternatively, the membrane electrode assembly is made to generate electricity. During the generation of electricity, liquid water is generated at the anode or the cathode.

A fuel cell system mounted on a vehicle includes a fuel cell, a humidity sensor configured to detect a humidity in a vehicle cabin of the vehicle, a cathode off-gas exhaust passage through which cathode off-gas emitted from the fuel cell is exhausted to outside the vehicle, an introducing port for cathode off-gas, provided in the cathode off-gas exhaust passage, a cathode off-gas introducing unit configured to introduce cathode off-gas emitted from the fuel cell, into the vehicle cabin of the vehicle via the introducing port, and a cathode off-gas introducing amount control unit configured to control an amount of the cathode off-gas introduced into the vehicle cabin of the vehicle in accordance with a humidity in the vehicle cabin of the vehicle, detected by the humidity sensor.

A system for detecting humidity level at a cathode of a fuel cell stack including one or more PEMFCs and determining a flooding probability of the stack based on the humidity level, includes a stack including a plurality of PEMFCs, each PEMFC including an exhaust; voltage detector; humidity detector; and controller. The controller may be configured to: receive a voltage as measured at an anode of one or more of the PEMFCs with the voltage detector; determine a humidity level at the exhaust of the one or more of the PEMFCs; and implement one or more actions based on the voltage and the humidity level, the actions including: reduce a load on the PEMFC; increase an air flow at a cathode of the one or more PEMFCs; decrease an inlet humidity at an inlet to the one or more PEMFCs; or increase a temperature of the one or more PEMFCs.

The present invention relates to a determination device (1; 1′) for a fuel cell system (2; 2′) having a fuel cell stack (4), comprising a virtual moisture sensor (7) for recording predefined determination values and a computing unit (10) for calculating a moisture value in a cathode inlet region (5) upstream of a cathode section of the fuel cell stack (4) based on the recorded determination values. The invention further relates to a fuel cell system (2; 2′) having such a determination device (1; 1′), methods for determining the moisture value, a computer program product (11) and a storage means having a computer program product (11) stored thereon.

A method increases the safety and/or the reliability of the operation of a fuel cell stack. The method determines that the fuel cell stack is in a space with a reduced air exchange rate. The method determines consumption information with respect to an oxygen consumption of the fuel cell stack within an interval of time. The method determines, on the basis of the air exchange rate, inflow information with respect to an amount of oxygen which was supplied to the space within the interval of time. The method determines an estimated value for an oxygen content of air in the space on the basis of the consumption information and on the basis of the inflow information.

A system for controlling purge operation of a fuel cell assembly includes a controller and one or more sensors configured to obtain respective sensor data. The fuel cell stack is configured to receive a stack coolant. The controller is configured to execute a first purge mode when at least one of a first enabling condition and a second enabling condition is met. The first purge mode defines a first group of setpoints, including a relatively low cathode stoichiometric ratio. The controller is configured to switch to a second purge mode when the coolant temperature is above a minimum warm-up temperature and a third mode when a relative humidity value of a stack cathode output falls below a threshold humidity. The second purge mode defines a second group of setpoints, including a relatively high cathode stoichiometric ratio.

Methods and systems are described for optimizing water discharge in fuel cell vehicles. The system includes a fuel cell stack, a blower for purging water from the fuel cell stack and a controller. The controller detects that an ambient temperature satisfies a threshold temperature. The controller determines the fuel cell vehicle is approaching a stopping location. The controller calculates a water discharge time prediction necessary to purge excess water from the fuel cell stack while the fuel cell vehicle is operating in response to detecting that the ambient temperature satisfies the threshold temperature and the fuel cell vehicle is approaching the stopping location. The water discharge time prediction is calculated based on the blower operating while the fuel cell stack is in at least one of an idle state and a stopped state as the fuel cell vehicle approaches the stopping location.

A system and method of controlling water imbalance in an electrochemical cell is provided. The method includes determining a present water imbalance in the electrochemical cell by summing a water.sub.in and a water.sub.created less a water.sub.out. Water.sub.in represents an amount of water introduced into the electrochemical cell by an oxidant feed gas; water.sub.created represents an amount of water created by the electrochemical cell from the electrochemical reaction; and water.sub.out represents an amount of water discharged from the electrochemical cell by an oxidant exhaust gas. The method includes tracking a cumulative water imbalance during operation of the electrochemical cell by repeatedly determining the present water imbalance and continuing to sum the results during operation. And, the method also includes adjusting a flow rate of the oxidant feed gas entering the electrochemical cell based on the cumulative water imbalance.