A fuel cell unit with a plurality of fuel cells defining a longitudinal axis and a main flow direction coaxial to the longitudinal axis. Fuel cell inlets and fuel cell outlets are arranged at opposite ends of the fuel cell unit and in line with the main flow direction. Also, a component comprising first fluid conduits arranged parallel to the main flow direction, the first fluid conduits comprising first fluid inlets and first fluid outlets arranged at opposite ends of the component and in line with the main flow direction. The component is arranged adjacent the fuel cell unit such that at least one of the first fluid inlets and the first fluid outlets of the component are arranged adjacent at least one of the fuel cell outlets and the fuel cell inlets such that a fluid flow may flow substantially parallel to the longitudinal axis of the apparatus in the first fluid conduits of the component and in the fuel cell unit and when passing from the component to the fuel cell unit or vice versa.

A fuel cell stack includes a bracket and a boss. The bracket includes an attachment surface. The bracket includes an attachment and detachment hole and an opening hole. The boss includes a bearing surface and a locking surface part. The locking surface part is connected to the bearing surface and protrudes in an outside direction such that at least a part of the locking surface part overlaps with the attachment surface part viewed from an attachment direction when a center of the attachment and detachment hole coincides with a center of the bearing surface.

In a fuel cell system, when filling hydrogen into a hydrogen tank is determined to be started, a transmitter configured to transmit a signal indicating pressure in the hydrogen tank to a hydrogen filling device transmits a first signal indicating that the pressure in the hydrogen tank is a first sensor value when the first sensor value detected by a first pressure sensor configured to detect pressure in a filling flow path connecting a filler port and the hydrogen tank is equal to or higher than a reference pressure predetermined to exceed the atmospheric pressure. Moreover, when the first sensor value is lower than the reference pressure, the transmitter transmits a second signal indicating that the pressure in the hydrogen tank is a second sensor value detected by a second pressure sensor configured to detect pressure in a supply flow path connecting the fuel cell and the hydrogen tank.

In a fuel cell system, when filling hydrogen into a hydrogen tank is determined to be started, a transmitter configured to transmit a signal indicating pressure in the hydrogen tank to a hydrogen filling device transmits a first signal indicating that the pressure in the hydrogen tank is a first sensor value when the first sensor value detected by a first pressure sensor configured to detect pressure in a filling flow path connecting a filler port and the hydrogen tank is equal to or higher than a reference pressure predetermined to exceed the atmospheric pressure. Moreover, when the first sensor value is lower than the reference pressure, the transmitter transmits a second signal indicating that the pressure in the hydrogen tank is a second sensor value detected by a second pressure sensor configured to detect pressure in a supply flow path connecting the fuel cell and the hydrogen tank.

Provided are a cell (1), a cell stack device (20), a module (30), and a module housing device (40). The cell (1) includes a metal plate (2) having a pair of surfaces, which are a first surface (2a) and a second surface that face each other, and containing Cr, an element portion (6) disposed on the metal plate (2), the element portion (6) including a first electrode layer (3), a solid electrolyte layer (4) located on the first electrode layer (3), and a second electrode layer (5) located on the solid electrolyte layer (4), and a first intermediate layer (9) located between the first surface (2a) of the metal plate (2) and the first electrode layer (3). The first intermediate layer 9 contains Cr.sub.2O.sub.3 and a first electrically conductive particle different from Cr.sub.2O.sub.3.

This fuel cell cartridge includes a plurality of cell stacks including a plurality of cells for forming a solid oxide fuel cell. A cell stack group including the plurality of cell stacks includes an inner cell stack group arranged in an inner region of a cell arrangement region and an outer cell stack group arranged in an outer region. The inner cell stack group and the outer cell stack group are connected in series and a current density of the outer cell stack group is configured to be higher than a current density of the inner cell stack group.

An electrochemical module including: a stack obtained by stacking, in a predetermined stacking direction, a plurality of electrochemical elements having a configuration in which an electrode layer, an electrolyte layer, and a counter electrode layer are formed along a substrate, via an annular sealing portion through which first gas that is one of reducing component gas and oxidative component gas flows; a container that includes an upper cover for pressing a first flat face in the stacking direction of the stack and a lower cover for pressing a second flat face on a side opposite to the first flat face, the stack being sandwiched between the upper cover and the lower cover; and a pressing mechanism that presses a portion to which the annular sealing portion is attached against the container in the stacking direction.

An electrochemical module including: a stack obtained by stacking, in a predetermined stacking direction, a plurality of electrochemical elements having a configuration in which an electrode layer, an electrolyte layer, and a counter electrode layer are formed along a substrate, via an annular sealing portion through which first gas that is one of reducing component gas and oxidative component gas flows; a container that includes an upper cover for pressing a first flat face in the stacking direction of the stack and a lower cover for pressing a second flat face on a side opposite to the first flat face, the stack being sandwiched between the upper cover and the lower cover; and a pressing mechanism that presses a portion to which the annular sealing portion is attached against the container in the stacking direction.

An embodiment fuel cell mounting system includes a fuel cell stack enclosure accommodating a fuel cell stack and having a flat structure, a support frame supporting the fuel cell stack enclosure, and a connection system connecting the fuel cell stack enclosure and the support frame, wherein the connection system is configured to elastically restore the fuel cell stack enclosure to a reference position.

A fuel cell stack has a prevention dam formed outside an alignment pin, such that a sealing material, which has viscosity and fluidity at a sealing temperature of a fuel cell, may be prevented from coming into contact with and adhering to the alignment pin, and pressure applied from the outside may be uniformly applied to the fuel cell stack.