The invention relates to a method for operating a fuel cell system (10) using a first operating mode, in which, when all of the fuel cell stacks (22, 26) are inactive, one fuel cell stack (22) is pre-heated using a coolant that is pre-heated by means of an electric heater (42) while bypassing all cooler circuits (58) of the active coolant circuits (14) via bypass lines (64) and the one pre-heated fuel cell stack (22) is activated in order to pre-heat an additional fuel cell stack (26) of the fuel cell system. Other operating modes for operating a fuel cell system are disclosed in additional embodiments.

A propulsion system includes a system for producing electricity that supplies electricity to at least one electric motor to which is mechanically coupled a propeller situated near a first longitudinal end of a nacelle that houses at least the system for producing electricity and the at least one electric motor. An air circulation channel, which receives a heat exchanger provided to allow the system for producing electricity to be cooled, extends inside the nacelle from a first end of the air circulation channel situated at the first longitudinal end of the nacelle. A part of the air circulation channel that is contiguous with its first end is delimited by an outer surface of cylindrical shape that surrounds the longitudinal axis of the nacelle.

A propulsion system includes a system for producing electricity that supplies electricity to at least one electric motor to which is mechanically coupled a propeller situated near a first longitudinal end of a nacelle that houses at least the system for producing electricity and the at least one electric motor. An air circulation channel, which receives a heat exchanger provided to allow the system for producing electricity to be cooled, extends inside the nacelle from a first end of the air circulation channel situated at the first longitudinal end of the nacelle. A part of the air circulation channel that is contiguous with its first end is delimited by an outer surface of cylindrical shape that surrounds the longitudinal axis of the nacelle.

A fuel cell power system including at least one fuel cell, a ram air system and a cooling circuit in which coolant is intended to circulate for regulating a temperature of the at least one fuel cell. The cooling circuit comprises a ram air heat exchanger in the ram air system and the ram air system comprises a nozzle. The fuel cell power system further comprises a water tank and the fuel cell power system is arranged to flow water from the water tank to the ram air system so as to spray water in ram air via the nozzle. Thus, dimensioning of the ram air system which includes the ram air heat exchanger is reduced.

A fuel cell power system including at least one fuel cell, a ram air system and a cooling circuit in which coolant is intended to circulate for regulating a temperature of the at least one fuel cell. The cooling circuit comprises a ram air heat exchanger in the ram air system and the ram air system comprises a nozzle. The fuel cell power system further comprises a water tank and the fuel cell power system is arranged to flow water from the water tank to the ram air system so as to spray water in ram air via the nozzle. Thus, dimensioning of the ram air system which includes the ram air heat exchanger is reduced.

A vehicle includes: a PCU cooling system; a PCU that is cooled by the PCU cooling system; a buck converter; an auxiliary battery that is charged through a buck operation of the buck converter; and an ECU that outputs a first target voltage and a second target voltage respectively to the buck converters. The buck converter is disposed inside the PCU, performs a buck operation so that a target voltage is generated, and outputs a stepped-down electric power to a power line. The buck converter is disposed outside the PCU, performs a buck operation so that a target voltage is generated, and outputs a stepped-down electric power to the power line. The ECU sets the target voltage higher than the target voltage when the ECU causes PCU to operate.

Systems and methods are disclosing providing for a fuel cell (“FC”) stack assembly utilizing bus bars that accommodate for variations in FC stack heights during assembly. In some embodiments, bus bars consistent with embodiments disclosed herein may be integrally formed with terminal plates out of a single piece of conductive material. Further embodiments of the bus bars disclosed herein may include structures configured to facilitating cooling of the bus bars during operation of the FC system.

A fuel cell vehicle includes a fuel cell, a fuel storage container, a container installation space, a fill lid box, and a fuel gas detector. The fuel cell is to generate power through an electrochemical reaction between a fuel gas and an oxidant gas. At least part of the fuel storage container is disposed in the container installation space. The fill lid box includes a gas fill port inside the fill lid box and has a communication hole to connect an inside of the fill lid box with the container installation space. The fuel gas is to be supplied through the gas fill port into the fuel storage container from an outside of the fuel cell vehicle. The fuel gas detector is disposed inside the fill lid box to detect a fuel gas leakage and to detect a fuel gas density in the container installation space.

A heat exchanger cooling system includes: a passage extending from a water tank and branching off into a first passage and a second passage at a branch portion provided in the middle of extension of the passage, the passage including a water discharge portion provided on a distal end side of the first passage so as to face a radiator; a pump configured to send water into the passage from the water tank; a first opening-closing valve provided in the first passage and configured to open and close the first passage; a second opening-closing valve provided in the second passage and configured to open and close the second passage; and a controlling portion configured to control an operation of the pump and to control opening and closing of the first opening-closing valve and the second opening-closing valve.

An exhaust air guide of a fuel cell stack is provided, in particular in a motor vehicle, with a cooling device which belongs to the functional environment of the fuel cell stack and is in the form of a cooler structure through which ambient air flows. At least some of the exhaust air of the fuel cell stack is guided into the cooler structure or behind the cooler structure, as viewed in the direction of flow of the ambient air through the cooler structure, to such an extent that, at the cooler structure, the exhaust air flow brings about an increase in the mass flow of the ambient air through the cooler structure in accordance with the jet pump principle or, at the cooler structure, the exhaust air flow, in accordance with the jet pump principle, brings about a pressure difference conveying at least a portion of the ambient air through the cooler structure.