A fuel cell system includes, in an auxiliary device case, a first layer, a second layer and a third layer in order from the end plate side, a coolant discharge pipe arranged in the first layer, cathode-side discharge pipes respectively connected to a plurality of oxygen-containing gas lead-out through holes which interpose the coolant discharge pipe, a plurality of first penetrating portions penetrating the first layer in the thickness direction, and a first connecting part provided in the second layer, extending in the layer direction of the second layer so as to straddle the coolant discharge pipe on the outer side, and connecting the plurality of first penetrating portions.

In a case where each of the temperature, the impedance, and the output current of a fuel cell stack falls within a predetermined range, the output voltage of the fuel cell stack is measured, and the measured output voltage is compared with a reference value to thereby determine the degree of degradation of the fuel cell stack.

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.

A bipolar plate for a four-fluid fuel cell includes a nonporous sub-plate and a porous sub-plate. The nonporous sub-plate includes a water management side, an opposing reactant side, and an internal coolant passage therebetween. The porous sub-plate includes a reactant side and an opposing water management side. The reactant side includes a first reactant flow field, and the water management side is fluidly connected to the water management side of the nonporous sub-plate. Embodiments of the invention include a method to operate the four-fluid fuel cell in thermal boost mode, and a method to accumulate and retain product water.

An ECU of a fuel cell system determines whether or not temperature information exceeds a temperature threshold for determination when receiving a signal related to power generation stop of a fuel cell stack during operation of a moving body. When the temperature information exceeds the determination temperature threshold, the ECU performs a stop control for stopping power generation of the fuel cell stack. On the other hand, when the temperature information is equal to or lower than the determination temperature threshold, the ECU performs an idle control for generating electric power smaller than electric power consumed by the air pump.

A fuel cell vehicle includes a fuel cell, an air compressor configured to draw in and discharge air, a cooler configured to cool air discharged from the air compressor, a humidifier configured to humidify air cooled by the cooler and to supply the humidified air to the fuel cell, and a system frame on which the fuel cell is disposed. The system frame accommodates at least a portion of each of the cooler and the humidifier therein.

A four-fluid bipolar plate for a fuel cell includes an oxidant flow field, a fuel reactant flow field, a dedicated coolant passage, and a water management flow field. The bipolar plate includes at least one porous layer. A first side of the porous layer is fluidly connected to the water management flow field via a plurality of pores that act as a bubble barrier. An opposing second side of the porous layer includes either the fuel reactant flow field or the oxidant flow field. In one example, the dedicated coolant passage is internal to the bipolar plate, and may be configured to flow an antifreeze-type coolant.

A fuel cell system includes, in an auxiliary device case, a first layer, a second layer and a third layer in order from the end plate side, a coolant discharge pipe arranged in the first layer, cathode-side discharge pipes respectively connected to a plurality of oxygen-containing gas lead-out through holes which interpose the coolant discharge pipe, a plurality of first penetrating portions penetrating the first layer in the thickness direction, and a first connecting part provided in the second layer, extending in the layer direction of the second layer so as to straddle the coolant discharge pipe on the outer side, and connecting the plurality of first penetrating portions.

A fuel cell system includes a fuel cell stack, hydrogen gas system auxiliary devices disposed outside the fuel cell stack, and air system auxiliary devices disposed adjacent to the hydrogen gas system auxiliary devices. The hydrogen gas system auxiliary devices include injectors, upstream side auxiliary devices provided on the upstream side of the injectors in the flow direction of hydrogen gas, and downstream side auxiliary devices provided on the downstream side of the injectors in the flow direction of the hydrogen gas. The upstream side auxiliary devices are disposed at positions farther away from the air system auxiliary devices than the downstream side auxiliary devices.

An air cleaner is provided in a cathode system device of a fuel cell system that is mounted in a fuel cell vehicle. The air cleaner comprises a casing having an internal space through which air flows, and an air filter accommodated in the internal space. The air filter has a flat plate shape, and is arranged on an outer side of a fuel cell stack in a horizontal direction, and in a state of being inclined with respect to the horizontal direction.