A system and method for cooling and humidifying a cathode subsystem of a fuel cell for an automobile. The system includes a compressor, an air input line including an intercooler configured to cool air output by the compressor, a fluid output line including a fluid injection system, a cathode stack configured to receive air via the air input line and output a fluid to the fluid output line, and an electronic processor. The electronic processor is configured to control the fluid injection system such that the fluid output from the cathode stack is injected into the air input line.

Systems and methods are provided for using fuel cell staging to reduce or minimize variations in current density when operating molten carbonate fuel cells with elevated CO.sub.2 utilization. The fuel cell staging can mitigate the amount of alternative ion transport that occurs when operating molten carbonate fuel cells under conditions for elevated CO.sub.2 utilization.

A method for determining an average oxidation state (AOS) of a redox flow battery system includes measuring a charge capacity for a low potential charging period starting from a discharged state of the redox flow battery system to a turning point of a charge voltage; and determining the AOS using the measured charge capacity and volumes of anolyte and catholyte of the redox flow battery system. Other methods can be used to determine the AOS for a redox flow battery system or use discharge voltage instead of charging voltage.

A system for capturing carbon dioxide in flue gas includes a fuel cell assembly including at least one fuel cell including a cathode portion configured to receive, as cathode inlet gas, the flue gas generated by the flue gas generating device or a derivative thereof, and to output cathode exhaust gas and an anode portion configure to receive an anode inlet gas and to output anode exhaust gas, a fuel cell assembly voltage monitor configured to measure a voltage across the fuel cell assembly, and a controller configured to receive the measured voltage across the fuel cell assembly from the fuel cell assembly voltage monitor, determine an estimated carbon dioxide utilization of the fuel cell assembly based on the measured voltage across the fuel cell assembly, and reduce the carbon dioxide utilization of the fuel cell assembly when the determined estimated carbon dioxide utilization is above a predetermined threshold utilization.

An exemplary fuel cell ship is a fuel cell ship for propelling a hull by using electric power supplied from a fuel cell that generates electric power through an electrochemical reaction of fuel, and includes a compartment including an emission source of the fuel and a first detector arranged in the compartment to detect the fuel. If the first detector detects that a concentration of the fuel in the compartment is equal to or greater than a first threshold value, a power supply to a non-explosion-proof device in the compartment is stopped.

A fuel cell ship includes a fuel cell that generates electric power by an electrochemical reaction of fuel, a propulsion device that generates propulsive force on a hull by electric power supplied from the fuel cell, a fuel supply pipe through which the fuel is supplied from a fuel tank housing the fuel to the fuel cell, a duct compartment that houses a part of the fuel supply pipe, a vent pipe that communicates with the duct compartment, and a fuel filling port that serves as an inlet for filling the fuel tank with the fuel. The fuel filling port is provided in the duct compartment.

A method for controlling a carbon dioxide utilization in a fuel cell assembly includes: measuring a voltage across the fuel cell assembly; determining an estimated carbon dioxide utilization of the fuel cell assembly based on at least the measured voltage across the fuel cell assembly by determining an expected voltage of the fuel cell assembly based on at least a temperature of the fuel cell assembly, a current density across the fuel cell assembly, a fuel utilization of the fuel cell assembly, and a cathode oxygen utilization of the fuel cell assembly; determining the estimated carbon dioxide utilization based on a comparison between the measured voltage and the determined expected voltage; comparing the determined estimated carbon dioxide utilization to a predetermined threshold utilization; and upon determining that the determined estimated carbon dioxide utilization is higher than the predetermined threshold utilization, reducing the carbon utilization of the fuel cell assembly.

A device for controlling compensation for an air flow rate upon discharge of hydrogen off-gas and a method for controlling compensation for an air flow rate using the same is an air flow rate control device configured to control a flow rate of air supplied to a fuel cell cathode through an air supply unit of a fuel cell system, wherein the air flow rate control device is configured to determine whether a fuel discharge valve of the fuel cell system is opened and determine a fuel diffusion amount per unit time, wherein the fuel diffusion amount corresponds to an amount of the hydrogen off-gas discharged through the fuel discharge valve and diffused into an air supply unit through a humidifier, and compensate a target air flow rate depending on an oxygen concentration reduction proportion, determined according to the determined fuel diffusion amount per unit time and flow rate information of the air supply unit.

Disclosed is a unitized regenerative fuel cell system, comprised of a unitized regenerative fuel cell able to operate in a fuel cell mode for electric power generation and in a water electrolysis mode for hydrogen and oxygen production, and a plurality of fire-detecting sensors for detecting fire in each zone of a tunnel, and configured to supply oxygen to zones wherein fire has not occurred if occurrence of fire has been detected in a tunnel, and a method for controlling the same.

The present invention provides, in a first aspect, an electrical generation system which includes an electrolyzer and a fuel cell system. The electrolyzer is coupled to a source of water and a power source. The electrolyzer is configured to generate oxygen and hydrogen utilizing water from the water source and electrical power from the power source. The fuel cell system is coupled to the electrolyzer to receive a flow of the hydrogen from the electrolyzer at an anode thereof. The fuel cell system includes a cathode having a cathode chamber coupled to a source of ambient air. The cathode chamber is coupled to the electrolyzer to selectively allow a flow of the oxygen from the electrolyzer to the cathode chamber and to selectively allow a flow of air from the source of ambient air to the cathode chamber. The fuel cell system is configured to generate electricity in a fuel cell reaction utilizing the hydrogen and the oxygen.