A fuel cell system includes a stack of fuel cells, a cathode recuperator configured to heat air using cathode exhaust output from the stack, and an air inlet baffle disposed between the cathode recuperator and the stack and containing at least two rows of apertures which are separated along a vertical direction and configured to provide the heated air output from the cathode recuperator to plural areas of the stack.

During startup of a fuel cell system, feed forward control is performed to increase the rotation number of an electric auxiliary device (compressor) to a modified steady state rotation number while maintaining a steady state rotation acceleration rate of the electric auxiliary device. In this manner, the overshoot amount is suppressed to an allowable overshoot amount. Otherwise, feed forward control is performed to increase the rotation number of the electric auxiliary device to a modified low steady state rotation number while maintaining a low steady state rotation acceleration rate. In this manner, the overshoot amount is suppressed to an allowable overshoot amount.

Methods and systems are provided for iron preformation in a redox flow battery. In one example, a method may include, in a first condition, discharging and then charging the redox flow battery, and in a second condition, charging the redox flow battery including preforming iron metal at a negative electrode of the redox flow battery, and thereafter entering an idle mode of the redox flow battery including adjusting one or more electrolyte conditions. In some examples, each of preforming the iron metal and adjusting the one or more electrolyte conditions may increase a battery charge capacity to greater than a threshold battery charge capacity.

Methods and systems are provided for iron preformation in a redox flow battery. In one example, a method may include, in a first condition, discharging and then charging the redox flow battery, and in a second condition, charging the redox flow battery including preforming iron metal at a negative electrode of the redox flow battery, and thereafter entering an idle mode of the redox flow battery including adjusting one or more electrolyte conditions. In some examples, each of preforming the iron metal and adjusting the one or more electrolyte conditions may increase a battery charge capacity to greater than a threshold battery charge capacity.

The invention relates to a fuel cell stack (10) having a plurality of fuel cells (20) which have an inlet-side cathode port (22), anode port (24) and coolant port (26) and an outlet-side cathode port (23), anode port (25) and coolant port (27), wherein the fuel cell stack (10) also has: two end plates (30, 31) between which the plurality of fuel cells (20) are arranged, wherein at least one of the end plates (30, 31) has inlet openings (32, 34, 36) and outlet openings (33, 35, 37) for a cathode gas, an anode gas and a coolant, which are each fluidically connected to the inlet-side and outlet-side cathode ports (22, 23), anode ports (24, 25) and coolant ports (26, 27), and at least one sensor (50) which is guided through at least one additional opening (39) in at least one of the end plates (30, 31) into one of the inlet-side or outlet-side cathode ports (22, 23), anode ports (24, 25) or coolant ports (26, 27). The invention also relates to a method for producing the fuel cell stack (10).

The fuel cell control system includes: a reactor; an air compressor, wherein the air compressor has a compressing cavity, the compressing cavity has a gas inlet and a gas outlet, a rotatable pressure wheel is disposed inside the compressing cavity, and the gas outlet is in communication with the reactor; a control flow channel, wherein a first end of the control flow channel is in communication with the gas-intake side of the pressure wheel, a second end of the control flow channel is in communication with the wheel-back side of the pressure wheel, and the control flow channel is provided with a return valve for regulating the flow rate of the control flow channel; and a central control unit, wherein the central control unit is communicatively connected to the return valve to control the opening degree of the return valve.

The present invention has an object of, without harming the manufacturability of a fuel cell system, and without increasing pressure loss of oxidant gas, enabling to layout heat exchangers of a cathode system in parallel. The fuel cell system includes a stack, anode system, cathode system and cooling system. The cathode system supplies oxidant gas to the stack in which fuel cells are laminated. The cooling system includes a plurality of heat exchangers which exchange heat between the oxidant gas and coolant. The plurality of heat exchangers is arranged in parallel in the cathode system. The cathode system includes a branching part which is more to an upstream side than each of the heat exchangers, and includes a merging part which is more to a downstream side than each of them. The heat exchangers are installed to be shifted from each other in each direction among up/down, front/rear and left/right.

The present method relates to a method for ascertaining the relative humidity (RH) at a cathode inlet (113) of a fuel cell stack (110) of a fuel cell system (100), having the following steps: detecting at least one physical supply air parameter (ZP) of a supply air (ZU) to the cathode inlet (113), detecting a supply air mass flow (ZM) of the supply air (ZU), determining a supply air water mass flow (ZWM) on the basis of the at least one supply air parameter (ZP) detected and of the supply air mass flow (ZM) detected, detecting at least one physical cathode inlet parameter (KP) at the cathode inlet (113), determining a humidifier water mass flow (BWM) on the basis of the at least one cathode inlet parameter (KP) detected using a humidifier characteristic map (BK), ascertaining the relative humidity (RH) at the cathode inlet (113) on the basis of the supply air water mass flow (ZWM) determined, the humidifier water mass flow (BWM) determined and the at least one cathode inlet parameter (KP) detected.

A method of monitoring operation of a reactor system includes causing a chemical reaction to occur within an assembly of the reactor system, and measuring a chemical composition of one or more reactants of the chemical reaction with spatial resolution at a plurality of points along a path within the assembly using a sensor system structured to implement distributed sensing. The sensor system includes an optical fiber sensing member provided at least partially within the assembly, wherein the optical fiber sensing member comprises a functionalized optical fiber based sensor device structured to exhibit a change in one or more optical properties in response to changes in the chemical composition of the one or more reactants.

A method of monitoring operation of a reactor system includes causing a chemical reaction to occur within an assembly of the reactor system, and measuring a chemical composition of one or more reactants of the chemical reaction with spatial resolution at a plurality of points along a path within the assembly using a sensor system structured to implement distributed sensing. The sensor system includes an optical fiber sensing member provided at least partially within the assembly, wherein the optical fiber sensing member comprises a functionalized optical fiber based sensor device structured to exhibit a change in one or more optical properties in response to changes in the chemical composition of the one or more reactants.