A state detection device for a fuel cell for generating power upon receiving a supply of anode gas and cathode gas, including an impedance acquisition unit configured to acquire a high frequency impedance based on a frequency selected from a high frequency band and a low frequency impedance based on a frequency selected from a low frequency band, the high frequency band including a frequency band which shows responsiveness at least to a state quantity of an anode electrode, the low frequency band including a frequency band which shows responsiveness at least to a state quantity of a cathode electrode, and an internal state quantity estimation unit configured to estimate each of the state quantity of the anode electrode and the state quantity of the cathode electrode by combining the acquired high frequency impedance and low frequency impedance, the state quantity of the anode electrode and the state quantity of the cathode electrode serving as internal states of the fuel cell.

An energy storage system includes a vanadium redox battery that interfaces with a control system to optimize performance and efficiency. The control system calculates optimal pump speeds, electrolyte temperature ranges, and charge and discharge rates. The control system instructs the vanadium redox battery to operate in accordance with the prescribed parameters. The control system further calculates optimal temperature ranges and charge and discharge rates for the vanadium redox battery.

A fuel cell system includes a fuel cell unit configured to generate an amount of electrical power for supply to a varying electrical load and a fuel cell controller configured to receive a first indication that the varying electrical load is at a local maximum within a predetermined period, and, in response, operate the fuel cell unit with an operational parameter having a first value such that the fuel cell unit produces a limited maximum amount of electrical power that is a predetermined percentage of a maximum rated power output of the fuel cell unit. The fuel cell controller is also configured to receive an indication that the varying electrical load has reduced, and, in response, operate the fuel cell unit with the operational parameter having a second value such that the fuel cell unit produces an amount of electrical power below the limited maximum amount of electrical power.

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.

A fuel cell system including a cathode gas supply system of a cathode gas bypass type includes a first flow rate sensor which detects a cathode gas flow rate to be supplied by the compressor, a second flow rate sensor which detects a cathode gas flow rate to be supplied to the fuel cell, a bypass valve which controls a cathode gas flow rate flowed in the bypass channel, a bypass valve controlling unit configured to execute an open/shut-off control of the bypass valve in accordance with an operation state of the fuel cell system, and a mismatch diagnosing unit configured to detect a mismatch of detected values of the first flow rate sensor and the second flow rate sensor based on the detected values of the both sensors during total shut-off of the bypass valve.

Provided are a recovery control system of a fuel cell and a method thereof. The recovery control system includes the fuel cell, a hydrogen supplier configured to supply hydrogen to the fuel cell, an air supplier configured to supply air to the fuel cell, an abnormality sensing unit configured to calculate a difference between a reference cell voltage predetermined depending on an output current of the fuel cell and a measured cell voltage of unit cells and to sense abnormality of air supply to a fuel cell stack based on the calculated difference between the reference cell voltage and the measured cell voltage or change in the difference, and a recovery controller configured to control the air supplier so as to increase a flow rate of air supplied to the fuel cell stack based on the change in the difference, when the abnormality sensing unit senses abnormality of air supply.

A fuel cell system for generating power by supplying anode gas and cathode gas to a fuel cell, comprising a compressor for supplying the cathode gas to the fuel cell, a pulsating operation unit causing a pressure of the anode gas to pulsate based on an operation state of the fuel cell system, a first target pressure setting unit setting a first target pressure of the cathode gas based on a request of the fuel cell, a second target pressure setting unit setting a second target pressure of the cathode gas for keeping a differential pressure in the fuel cell to be within a permissible differential pressure range according to the pressure of the anode gas in the fuel cell, and a compressor control unit controlling the compressor based on the first target pressure and the second target pressure. The second target pressure setting unit sets the second target pressure based on an upper limit target pressure in pulsation on the pulsation of the pressure of the anode gas.

A fuel cell system includes a supply unit configured to supply cathode gas to a fuel cell, a bypass valve configured to bypass the cathode gas to be supplied to the fuel cell by the supply unit, a detection unit configured to detect a state of the cathode gas to be supplied to the fuel cell without being bypassed by the bypass valve, a pressure adjusting unit configured to adjust a pressure of the cathode gas to be supplied to the fuel cell, a calculation unit configured to calculate a target flow rate and a target pressure of the cathode gas to be supplied to the fuel cell according to an operating state of the fuel cell, an operating state control unit configured to control an operation amount of at least one of the pressure adjusting unit and the supply unit on the basis of a flow rate and the pressure of the cathode gas detected by the detection unit and the target flow rate and the target pressure calculated by the calculation unit, a bypass valve control unit configured to open and close the bypass valve on the basis of the flow rate of the cathode gas detected by the detection unit and the target flow rate calculated by the calculation unit, and a pressure compensation unit configured to compensate for the pressure of the cathode gas to be supplied to the fuel cell by increasing the at least one operation amount controlled by the operating state control unit or by decreasing an opening speed of the bypass valve when the bypass valve is opened.

The present disclosure generally relates to systems and methods in a vehicle or powertrain system including an air stream flowing through an air compressor and an air cooler into a fuel cell stack, an air stream flowing out of the fuel cell stack to an ambient through a backpressure valve, one or more sensors for measuring pressure or temperature in the first air stream or second air stream, and a controller controlling the flow of the first air stream, the flow of the scond air stream and the opening of the backpressure valve.

A fuel cell system includes a fuel cell stack configured to include a cathode and an anode, an air supplier configured to supply air to the cathode, and an air intake pipe configured to connect an outlet of the air supplier and an inlet of the cathode to each other and having an opening adjustable valve provided thereto. A controller is configured to adjust an opening of the valve according to a supplied amount of air to control a flow rate of air supplied to the cathode. Thereby, the fuel cell stack is prevented from drying-out, and durability of a fuel cell is improved.