JP6457689B1 - Fuel cell and cell stack device - Google Patents

Abstract

A fuel cell and a cell stack device capable of stably burning surplus gas are provided. A fuel cell includes a fuel cell main body and a cap member. The fuel cell body 3 includes a gas flow path 31, a base end portion that is a supply side of the gas flow path 31, and a distal end portion that is a discharge side of the gas flow path 31. The cap member 4 is attached to the distal end portion of the fuel cell body 3. The cap member 4 has a gas discharge port 431. Further, the cap member 4 has a wall portion 44 that is disposed along the outer peripheral edge of the gas exhaust port 431 at a distance from the gas exhaust port 431. [Selection] Figure 8

Description

  The present invention relates to a fuel cell and a cell stack device.

  The fuel cell generates power by supplying the fuel gas to the fuel electrode and supplying the oxygen-containing gas to the air electrode. The surplus fuel gas and oxygen-containing gas discharged without being used for power generation of the fuel battery cell are burned and used as a heat source. As such a fuel cell, JP, 2012-14850, A (patent documents 1) is mentioned, for example.

JP 2012-14850 A

  In the fuel cell having the above-described configuration, it is preferable to stably burn the surplus gas in order to keep the fuel cell at an appropriate operating temperature.

  Then, this invention makes it a subject to provide the fuel cell and cell stack apparatus which can burn an excess gas stably.

  The fuel cell according to the first aspect of the present invention includes a fuel cell body and a cap member. The fuel cell body has a gas flow path, a base end portion that is a supply side of the gas flow path, and a distal end portion that is a discharge side of the gas flow path. The cap member is attached to the tip of the fuel cell body. The cap member has a gas discharge port. Moreover, a cap member has a wall part arrange | positioned at intervals from the gas exhaust port along the outer periphery of a gas exhaust port.

  According to this structure, the cap member has a wall part along the outer periphery of a gas exhaust port. By this wall portion, it is possible to suppress the gas flowing on the front end surface of the cap member from directly colliding with the root of the flame formed by burning the surplus gas discharged from the gas discharge port. As a result, surplus gas can be combusted stably.

  Preferably, the wall portion includes a plurality of protrusions.

  Preferably, the wall portion extends intermittently along the outer peripheral edge of the gas discharge port.

  Preferably, the cap member has a cylindrical heat conducting portion, a cylindrical protruding portion, and a combustion portion. The heat conducting portion covers the outer peripheral surface of the tip portion of the fuel cell body. The protruding portion extends from the heat conducting portion along a first direction that is a direction in which the gas flow path extends. A combustion part is arrange | positioned so that a protrusion part may be plugged up. A combustion part has the gas discharge port mentioned above.

  Preferably, the combustion part is disposed at a distance from the tip surface of the fuel cell body.

  Preferably, the heat conducting portion is longer than the protruding portion in the first direction.

  Preferably, the main surface of the heat conducting portion and the main surface of the protruding portion constitute a plane.

  Preferably, the boundary part between the combustion part and the protruding part has a chamfered shape.

  A cell stack device according to a second aspect of the present invention includes any one of the fuel cells described above and a manifold that supports a base end portion of the fuel cell body.

  The present invention can provide a fuel cell and a cell stack device that can stably burn surplus gas.

The perspective view of a cell stack apparatus. The perspective view of a fuel cell. The front view of a fuel cell. The perspective view of a fuel cell main body. Sectional drawing of a fuel cell main body. FIG. 6 is a sectional view taken along line VI-VI in FIG. 3. VII-VII sectional view taken on the line of FIG. VIII-VIII sectional view taken on the line of FIG. The top view of a cap member. The top view of the cap member which concerns on a modification. The top view of the cap member which concerns on a modification. The top view of the cap member which concerns on a modification. The top view of the cap member which concerns on a modification. The figure equivalent to FIG. 8 of the fuel cell concerning a modification. The figure equivalent to FIG. 8 of the fuel cell concerning a modification. The figure equivalent to FIG. 6 of the fuel cell concerning a modification. The figure equivalent to FIG. 2 of the fuel cell concerning a modification.

  Hereinafter, embodiments of a fuel battery cell and a cell stack device according to the present invention will be described with reference to the drawings. In the following description, unless otherwise specified, the longitudinal direction, the width direction, and the thickness direction mean the longitudinal direction (an example of the first direction), the width direction, and the thickness direction of the fuel cell.

[Cell stack device 100]
As shown in FIG. 1, the cell stack device 100 includes a plurality of fuel cells 10 and a manifold 20. Each fuel cell 10 is supported by a manifold 20. The fuel cell 10 extends upward from the manifold 20. Further, the fuel cells 10 are arranged at intervals from each other along the longitudinal direction (z-axis direction) of the manifold 20. Moreover, each fuel cell 10 is arranged along the thickness direction so that the principal surfaces of the fuel cells 10 face each other.

  Each fuel cell 10 is electrically connected to each other via a current collecting member (not shown). The current collecting member is formed of a conductive material such as a fired body of oxide ceramics or metal. The manifold 20 distributes a gas such as fuel gas to the gas flow path 31 (see FIG. 2) of each fuel cell 10. The manifold 20 is hollow and has an internal space. Fuel gas is supplied to the internal space of the manifold 20 through the introduction pipe 21.

[Fuel battery cell 10]
As shown in FIGS. 2 and 3, the fuel battery cell 10 includes a fuel battery cell main body 3 and a cap member 4. The fuel battery cell 10 has a flat shape.

[Fuel battery cell body 3]
As shown in FIG. 4, the fuel cell main body 3 has a plurality of gas flow paths 31, a base end portion 32, and a tip end portion 33. One end (lower end in FIG. 4) in the longitudinal direction (x-axis direction) of the fuel cell body 3 is a base end 32, and the other end (upper end in FIG. 4) is a distal end 33. . Note that the distal end portion 33 of the fuel cell body 3 is mainly constituted by the support substrate 110. Specifically, the tip 33 of the fuel cell body 3 is constituted by a support substrate 110 covered with a dense film such as an electrolyte 140 described later.

  The gas flow path 31 extends from the base end portion 32 to the tip end portion 33 in the fuel cell main body 3. That is, the gas flow path 31 extends in the longitudinal direction (x-axis direction) of the fuel cell body 3. In addition, the gas flow paths 31 extend substantially in parallel with each other at an interval in the width direction (y-axis direction) of the fuel cell body 3. Each gas flow path 31 is preferably not formed at both ends in the width direction of the fuel cell body 3. In the present embodiment, the longitudinal direction (x-axis direction) of the fuel cell body 3 corresponds to the first direction of the present invention.

  The base end portion 32 of the fuel cell body 3 is an end portion on the supply side of the gas flow path 31 in the fuel cell body 3. The fuel cell body 3 is supported by the manifold 20 at the base end portion 32.

  The front end portion 33 of the fuel cell main body 3 is an end portion on the discharge side of the gas passage 31 in the fuel cell main body 3. The distal end portion 33 is an end portion opposite to the proximal end portion 32. The tip 33 of the fuel cell body 3 is a free end. The fuel cell body 3 is supported by the manifold 20 in a cantilever state and is self-supporting.

  The fuel cell body 3 has a flat shape. The fuel cell body 3 is a so-called cylindrical plate type fuel cell. As shown in FIG. 2, the fuel cell body 3 includes a first main surface 301, a second main surface 302 opposite to the first main surface 301, a first main surface 301, and a second main surface 302. And a pair of side surfaces 303 connecting the two. The first main surface 301, the second main surface 302, and the pair of side surfaces 303 constitute the outer peripheral surface of the fuel cell body 3. The first main surface 301 and the second main surface 302 face opposite to each other and extend in parallel to each other. The distance between the first main surface 301 and the second main surface 302 is substantially equal to the thickness of the support substrate 110. The thickness of the support substrate 110 is, for example, 1 to 10 mm.

  The fuel cell body 3 has a base end face 304 (lower end face in FIG. 2) and a front end face 305 (upper end face in FIG. 2). The proximal end surface 304 and the distal end surface 305 are end surfaces in the longitudinal direction of the fuel cell body 3. The gas flow path 31 extends from the proximal end surface 304 to the distal end surface 305. The gas flow path 31 is open at the proximal end surface 304 and the distal end surface 305. Fuel gas is supplied into the gas flow path 31 on the base end face 304 side, and fuel gas is discharged from the gas flow path 31 on the front end face 305 side. That is, the opening of the gas flow path 31 formed on the base end face 304 side is a gas supply port. And the opening of the gas flow path 31 formed in the front end surface 305 side is a gas discharge port. The base end surface 304 of the fuel cell body 3 faces the internal space of the manifold 20.

  As shown in FIG. 4, the fuel cell body 3 includes a support substrate 110 and a plurality of power generation element portions 120. Each power generation element unit 120 is disposed on both surfaces of the support substrate 110. Each power generation element unit 120 may be disposed only on one side of the support substrate 110. The respective power generation element portions 120 are arranged at intervals in the longitudinal direction of the fuel cell body 3. That is, the fuel cell body 3 according to the present embodiment is a so-called horizontal stripe type. The power generation element units 120 are electrically connected to each other by an electrical connection unit 160 (see FIG. 5). The power generation element unit 120 generates power using the fuel gas flowing through the gas flow path 31 and the oxidant gas flowing through the outer peripheral surface of the fuel cell body 3.

[Support substrate]
The support substrate 110 has the gas flow path 31 described above formed therein. The support substrate 110 is insulative. That is, the support substrate 110 does not have electronic conductivity. The support substrate 110 is formed of ceramics, for example. Specifically, the support substrate 110 may be made of CSZ (calcia stabilized zirconia), NiO (nickel oxide) and YSZ (8YSZ) (yttria stabilized zirconia), It may be composed of NiO (nickel oxide) and Y ₂ O ₃ (yttria), or may be composed of MgO (magnesium oxide) and MgAl ₂ O ₄ (magnesia alumina spinel). The support substrate 110 is porous. The porosity of the support substrate 110 is, for example, 20 to 60%.

  As shown in FIG. 5, the support substrate 110 has a plurality of first recesses 117. Each first recess 117 is formed on each main surface of the support substrate 110. The first recesses 117 are formed at intervals in the longitudinal direction of the support substrate 110.

[Power generation element section 120]
Each power generation element unit 120 includes a fuel electrode 130, an electrolyte 140, and an air electrode 150. Each power generation element unit 120 further includes a reaction preventing film 121.

  The fuel electrode 130 is a fired body made of a porous material having electron conductivity. The fuel electrode 130 includes a fuel electrode current collector 131 and a fuel electrode active unit 132. The fuel electrode current collector 131 is disposed in the first recess 117. Each fuel electrode current collector 131 has a second recess 131a and a third recess 131b. The anode active part 132 is disposed in the second recess 131a.

The fuel electrode current collector 131 may be composed of, for example, NiO (nickel oxide) and YSZ (8YSZ) (yttria-stabilized zirconia), or from NiO (nickel oxide) and Y ₂ O ₃ (yttria). It may be composed of NiO (nickel oxide) and CSZ (calcia stabilized zirconia). The thickness of the fuel electrode current collector 131, that is, the depth of the first recess 117 is 50 to 500 μm. Note that the nickel oxide changes to metallic nickel when the reducing gas is supplied to the fuel electrode 130.

  The anode active portion 132 may be composed of, for example, NiO (nickel oxide) and YSZ (8YSZ) (yttria stabilized zirconia), or composed of NiO (nickel oxide) and GDC (gadolinium-doped ceria). May be. The thickness of the fuel electrode active part 132 is 5 to 30 μm. Note that the nickel oxide changes to metallic nickel when the reducing gas is supplied to the fuel electrode 130.

  The electrolyte 140 is disposed so as to cover the fuel electrode 130. Specifically, the electrolyte 140 extends in the longitudinal direction of the fuel cell 10 from one interconnector 161 to another interconnector 161. That is, the electrolyte 140 and the interconnector 161 are alternately arranged in the longitudinal direction of the fuel cell 10.

  The electrolyte 140 is a fired body made of a dense material that has ionic conductivity and does not have electronic conductivity. The electrolyte 140 may be composed of, for example, YSZ (8YSZ) (yttria stabilized zirconia) or LSGM (lanthanum gallate). The thickness of the electrolyte 140 is, for example, 3 to 50 μm.

The reaction preventing film 121 is a fired body made of a dense material, has substantially the same shape as the fuel electrode active portion 132 in a plan view (viewed in the z-axis direction), and is substantially the same position as the fuel electrode active portion 132. Is arranged. The reaction preventing film 121 suppresses occurrence of a phenomenon in which YSZ in the electrolyte 140 reacts with Sr in the air electrode 150 to form a reaction layer having a large electric resistance at the interface between the electrolyte 140 and the air electrode 150. Is provided. The reaction preventing film 121 is made of, for example, GDC = (Ce, Gd) O ₂ (gadolinium-doped ceria). The thickness of the reaction preventing film 121 is, for example, 3 to 50 μm.

The air electrode 150 is disposed on the reaction preventing film 121. The air electrode 150 is a fired body made of a porous material having electron conductivity. The air electrode 150 may be made of, for example, LSCF = (La, Sr) (Co, Fe) O ₃ (lanthanum strontium cobalt ferrite), LSF = (La, Sr) FeO ₃ (lanthanum strontium ferrite), LNF = La (Ni, Fe) O ₃ (lanthanum nickel ferrite), LSC = (La, Sr) CoO ₃ (lanthanum strontium cobaltite), or the like may be used. Moreover, the air electrode 150 may be comprised by two layers, the 1st layer (inner layer) comprised from LSCF, and the 2nd layer (outer layer) comprised from LSC. The thickness of the air electrode 150 is, for example, 10 to 100 μm.

The electrical connection unit 160 is configured to electrically connect adjacent power generation element units 120. The electrical connection unit 160 includes an interconnector 161 and an air electrode current collector 162. The interconnector 161 is disposed in the third recess 131b. The interconnector 161 is a fired body composed of a dense material having electronic conductivity. The interconnector 161 may be made of, for example, LaCrO ₃ (lanthanum chromite) or (Sr, La) TiO ₃ (strontium titanate). The thickness of the interconnector 161 is, for example, 10 to 100 μm.

The air electrode current collector 162 is disposed so as to extend between the interconnector 161 and the air electrode 150 of the adjacent power generation element unit 120. The air electrode current collector 162 is a fired body made of a porous material having electronic conductivity. The air electrode current collector 162 may be composed of, for example, LSCF = (La, Sr) (Co, Fe) O ₃ (lanthanum strontium cobalt ferrite), or LSC = (La, Sr) CoO ₃ (lanthanum strontium). Cobaltite) or Ag (silver) or Ag-Pd (silver palladium alloy). The thickness of the air electrode current collector 162 is, for example, 50 to 500 μm.

[Cap member 4]
As shown in FIGS. 2 and 3, the cap member 4 is attached to the distal end portion 33 of the fuel cell body 3. The cap member 4 covers the outer peripheral surface of the distal end portion 33 of the fuel cell body 3. In the present embodiment, the cap member 4 is only placed on the tip portion 33 of the fuel cell body 3 and is not joined to the tip portion 33.

  The cap member 4 is made of metal. The thermal conductivity of the metal constituting the cap member 4 is higher than the thermal conductivity of the material mainly constituting the tip portion 33 of the fuel cell body 3. Specifically, the thermal conductivity of the metal constituting the cap member 4 is higher than the thermal conductivity of the material constituting the support substrate 110.

  The cap member 4 is made of, for example, a heat-resistant Fe-based alloy (stainless steel), an Fe—Ni-based alloy, a Ni-based alloy, a Co-based alloy, or the like. The material constituting the cap member 4 is preferably a metal material that forms a film mainly composed of chromium oxide or a film mainly composed of aluminum oxide as an oxide film because it is exposed to a high temperature for a long time by combustion. A metal material that forms a film mainly composed of aluminum oxide having high oxidation resistance is preferable. In addition, a main component means that it is 50 mass% or more of the whole. Further, in the portion where the tip portion 33 of the fuel cell body 3 and the cap member 4 abut, the element in the fuel cell body 3 and the element in the cap member 4 may react with each other. Depending on the reaction, the fuel cell body 3 and the cap member 4 may be unintentionally physically joined. The film containing chromium oxide as a main component easily reacts with chromium oxide and the elements in the fuel cell body 3, but when a metal material that forms a film containing aluminum oxide as a main component is used, aluminum oxide and the fuel cell are used. Since the element in the cell main body 3 is poorly reactive, the mutual reaction between the fuel cell main body 3 and the cap member 4 does not occur, and it is possible to prevent an unintentionally physically joined state. Therefore, the material constituting the cap member 4 is most preferably a metal material that forms a film mainly composed of aluminum oxide.

  The cap member 4 includes a heat conducting part 41, a protruding part 42, and a combustion part 43. The heat conduction part 41, the protrusion part 42, and the combustion part 43 may be comprised by one member, and may be comprised by connecting another member. In this embodiment, the heat conduction part 41, the protrusion part 42, and the combustion part 43 are integrally comprised by one member.

  The heat conduction part 41 is cylindrical. Of the outer peripheral surface of the heat conducting portion 41, the surface facing the thickness direction (z-axis direction) is the main surface, and the surface facing the width direction (y-axis direction) is the side surface. The heat conducting portion 41 covers the outer peripheral surface of the tip portion 33 of the fuel cell body 3. The heat conducting portion 41 faces the outer peripheral surface of the tip end portion 33 of the fuel cell body 3. That is, the heat conducting portion 41 faces the first main surface 301, the second main surface 302, and the side surface 303 at the tip end portion 33 of the fuel cell body 3. The heat conduction part 41 of the fuel cell body 3 transmits the heat transmitted from the combustion part 43 to the outer peripheral surface of the tip part 33 of the fuel cell body 3.

  The inner surface of the heat conducting portion 41 and the first and second main surfaces 301 and 302 of the tip portion 33 of the fuel cell body 3 may not be in contact with each other, or may be in contact with each other. It may be in contact with. As shown in FIG. 6, when the inner side surface of the heat conducting portion 41 and the first and second main surfaces 301 and 302 of the tip end portion 33 of the fuel cell body 3 are not in contact with each other, the gap H1 between them is, for example, Preferably it is 500 micrometers or less, More preferably, it is 250 micrometers or less, More preferably, it is 100 micrometers. The preferable range of the gap H1 means the maximum gap when the gap is not constant (including a case where part of the gap abuts).

  In addition, since the heat conduction part 41 is made of a metal having high heat conductivity, it can be transmitted to the outer peripheral surface of the tip part 33 of the fuel cell main body 3 by radiant heat even through the gap H1.

  The inner side surface of the heat conducting portion 41 and the side surface 303 of the tip end portion 33 of the fuel cell body 3 may not be in contact, may be in contact, or may be in partial contact. As shown in FIG. 7, when the inner side surface of the heat conducting portion 41 and the side surface 303 of the tip end portion 33 of the fuel cell body 3 are not in contact with each other, the gap H2 between them is preferably 500 μm or less, for example. Preferably it is 250 micrometers or less, More preferably, it is 100 micrometers. The preferable range of the gap H2 means the maximum gap when the gap is not constant (including a case where a part thereof is in contact).

  As shown in FIGS. 2, 3, and 6, the protrusion 42 has a cylindrical shape. The protruding portion 42 extends upward from the heat conducting portion 41. The protruding portion 42 extends continuously upward from the heat conducting portion 41. That is, no stepped portion or the like is formed between the protruding portion 42 and the heat conducting portion 41. For this reason, the main surface of the protrusion part 42 and the main surface of the heat-conducting part 41 comprise the plane. Of the outer peripheral surface of the protrusion 42, the surface facing the thickness direction (z-axis direction) is the main surface, and the surface facing the width direction (y-axis direction) is the side surface.

  The protruding portion 42 has a plurality of constricted portions 421 that are recessed inward. In the present embodiment, a plurality of constricted portions 421 are provided. In the present embodiment, the projecting portion 42 has two pairs of constricted portions 421. The two pairs of narrowed portions 421 are disposed on each main surface of the protruding portion 42. Each narrowed portion 421 extends along the width direction (y-axis direction) of the fuel cell 10. Each pair of constricted portions 421 is recessed inward so as to approach each other. That is, each pair of constricted portions 421 is recessed inward in the thickness direction (z-axis direction) of the fuel cell 10. The depth D1 of each constricted portion 421 is, for example, about 0.5 to 5.0 mm. The depth D1 means the dimension at the most recessed position of the narrowed portion 421.

  One pair of narrowed portions 421 and the other pair of narrowed portions 421 are arranged with a gap in the width direction (y-axis direction). One pair of narrowed portions 421 is disposed on the first end portion side in the width direction, and the other pair of narrowed portions 421 is disposed on the second end portion side in the width direction.

  The thickness T1 of the protrusion 42 at the position where the pair of constricted portions 421 is formed is preferably smaller than the thickness T2 of the fuel cell body 3. With this configuration, the lower surface of each narrowed portion 421 comes into contact with the front end surface 305 of the fuel cell body 3. Preferably, the lower surface of each narrowed portion 421 is in contact with the distal end surface 305 in a region where the opening of the gas flow path 31 is not formed. Thus, the cap member 4 is supported by the fuel cell main body 3 by the lower surface of each narrowed portion 421 being in contact with the front end surface 305 of the fuel cell main body 3. Note that the cap member 4 is not joined to the fuel cell body 3, but may be joined to the fuel cell body 3 with a joining material or the like.

  As shown in FIGS. 3 and 6, the length L <b> 1 of the heat conducting portion 41 is longer than the length L <b> 2 of the protruding portion 42 in the longitudinal direction of the fuel cell 10. The length L1 of the heat conducting unit 41 is, for example, about 3 mm to 50 mm. Moreover, the length L2 of the protrusion part 42 is about 1-20 mm, for example. The ratio (L1 / L2) of the length L1 of the heat conducting portion 41 to the length L2 of the protruding portion 42 is, for example, about 1.5 to 50.

  Note that the length L1 of the heat conducting unit 41 means the dimension of the heat conducting unit 41 in the longitudinal direction (x-axis direction) of the fuel cell 10. The length L1 of the heat conducting portion 41 refers to the distance from the lower end of the cap member 4 to the front end surface 305 of the fuel cell body 3 in the front view shown in FIG. 3 or the side view shown in FIG. Further, the length L2 of the protruding portion 42 means the dimension of the protruding portion 42 in the longitudinal direction (x-axis direction) of the fuel cell 10. The length L2 of the protrusion 42 refers to the distance from the upper end of the cap member 4 to the front end surface 305 of the fuel cell body 3 in the front view shown in FIG. 3 or the side view shown in FIG.

  As shown in FIGS. 2, 3, and 6, the combustion part 43 is disposed so as to close the cylindrical protrusion 42. The internal space S of the cap member 4 is defined by the combustion portion 43, the protrusion 42, and the tip surface 305 of the fuel cell body 3.

  The combustion part 43 is disposed at a distance from the front end surface 305 of the fuel cell main body 3 in the longitudinal direction (x-axis direction). The combustion part 43 faces the front end surface 305 of the fuel cell body 3. The combustion part 43 has a flat plate shape.

  The combustion unit 43 has a plurality of gas discharge ports 431. Each gas discharge port 431 is a through hole and penetrates in the longitudinal direction of the fuel cell 10. Each gas discharge port 431 extends in the same direction as the gas flow path 31 of the fuel cell body 3. Each gas discharge port 431 communicates the internal space S of the cap member 4 with the outside. Excess gas that has not been used for power generation of the fuel cell body 3 is discharged from the gas discharge port 431 of the combustion unit 43. The number of gas exhaust ports 431 may be the same as or different from the number of gas flow paths 31. Each gas discharge port 431 is arranged at intervals along the width direction (y-axis direction).

  As shown in FIGS. 8 and 9, the cap member 4 has a plurality of wall portions 44 on the tip surface of the combustion portion 43. The wall portion 44 is disposed along the outer peripheral edge of the gas discharge port 431. The wall portion 44 extends annularly around the gas discharge port 431. Moreover, the wall part 44 is arrange | positioned at intervals from the outer periphery of the gas exhaust port 431. The distance D2 between the wall portion 44 and the outer peripheral edge of the gas discharge port 431 is not particularly limited, but is, for example, about 0.1 to 2 mm.

The height H of the wall 44 is, for example, about 10 to 1000 μm. The wall portion 44 can be formed by, for example, embossing, vapor deposition, sputtering, or the like. In the vapor deposition method or the sputtering method, for example, the wall portion 44 may be formed of the same material as the cap member 4, and in addition, Al ₂ O ₃ , Y ₂ O ₃ , FeO, Fe ₂ O _3, and ZrO _The wall portion 44 may be formed of at least one selected from ₂ or the like.

[Operation of cell stack device]
The operation of the cell stack device 100 configured as described above will be described. The cell stack apparatus 100 operates as follows, for example.

  In the cell stack apparatus 100, fuel gas (hydrogen gas or the like) is supplied from the introduction pipe 21 into the manifold 20. Then, this fuel gas is supplied to the gas flow path 31 of each fuel cell body 3. On the other hand, an oxygen-containing gas (air or the like) is supplied to the outside of each fuel cell body 3.

By supplying the fuel gas and the oxygen-containing gas in this manner, an oxygen partial pressure difference, that is, a potential difference is generated between the front and back surfaces of the electrolyte 140 in each power generation element unit 120. When the fuel cell 10 is electrically connected to an external load in this state, an electrochemical reaction represented by the following formula 1 occurs in the air electrode 150 and an electrochemical reaction represented by the following formula 2 occurs in the fuel electrode 130. .
(1/2) O ₂ + 2e ⁻ → O ²⁻ (Formula 1)
H ₂ + O ²⁻ → H ₂ O + 2e ⁻ (Formula 2)

  Thereby, an electric current flows in the fuel cell main body 3, and it will be in an electric power generation state. In this power generation state, electric power is taken out from the fuel cell body 3.

  And after the surplus fuel gas which was not used for power generation among the fuel gas which flows through the gas flow path 31 of the fuel cell body 3 is discharged from the discharge port of the gas flow path 31 to the internal space S of the cap member 4, The gas is discharged to the outside through the gas discharge port 431 of the cap member 4. The surplus fuel gas discharged from the gas discharge port 431 of the cap member 4 is mixed with the oxygen-containing gas flowing outside and burned.

  The heat generated by this combustion is transmitted to the heat conducting unit 41 via the burning unit 43 and the protruding unit 42. As a result, the outer peripheral surface of the tip portion 33 of the fuel cell body 3 is heated, and the temperature difference between the outer peripheral surface of the tip portion 33 and the tip surface 305 is reduced.

[Modification]
As mentioned above, although embodiment of this invention was described, this invention is not limited to these, A various change is possible unless it deviates from the meaning of this invention.

Modification 1
As shown in FIG. 10, the wall 44 may be configured by a plurality of protrusions 441. Each protrusion 441 is arranged along the outer peripheral edge of the gas discharge port 431. In addition, each protrusion part 441 may be in contact with the adjacent protrusion part 441, may be arrange | positioned at intervals, and these combination may be sufficient as it.

Modification 2
In the said embodiment, although the wall part 44 was extended continuously so that the gas exhaust port 431 might be enclosed, it is not limited to this. For example, as shown in FIG. 11, the wall portion 44 may extend intermittently along the outer peripheral edge of the gas discharge port 431.

Modification 3
In the said embodiment, although the wall part 44 is extended along the outer periphery whole periphery of the gas exhaust port 431, it is not limited to this. For example, as shown in FIG. 12, the wall portion 44 may extend along only a part of the outer peripheral edge of the gas discharge port 431. For example, the wall portion 44 may extend in an arc shape.

Modification 4
In the said embodiment, although the several wall part 44 is formed independently, respectively, it is not limited to this. For example, as shown in FIG. 13, each wall 44 may be connected to an adjacent wall 44. That is, the wall portions 44 may be formed integrally with each other.

Modification 5
In the said embodiment, although the cross-sectional shape of the wall part 44 in the surface orthogonal to the direction where the wall part 44 extends is a semicircle shape, the shape of the wall part 44 is not limited to this. For example, as shown in FIG. 14, the cross-sectional shape of the wall portion 44 may be a rectangular shape or other shapes.

Modification 6
In the said embodiment, although the wall part 44 was formed for every gas discharge port 431, it is not limited to this. For example, the wall portion 44 may be formed only in any one of the plurality of gas discharge ports 431.

Modification 7
As shown in FIG. 15, the boundary part 45 between the combustion part 43 and the protrusion part 42 may have a chamfered shape. Specifically, the boundary portion 45 between the main surface (upper surface) of the combustion portion 43 and the main surface of the protruding portion 42 may have a chamfered shape. For example, the boundary 45 may be R chamfered or C chamfered. Thus, when the boundary part 45 has a chamfered shape, the oxygen-containing gas from the lower part goes around to the gas discharge port 431, and combustibility improves.

Modification 8
In the above embodiment, the cap member 4 is attached to the horizontally striped fuel cell body 3 in which a plurality of power generation element portions 120 are arranged on each main surface of the support substrate 110, but the cap member 4 is a so-called cap member 4. It can also be attached to a vertically striped fuel cell body.

Modification 9
In the above embodiment, the gas flow path 31 extends in the longitudinal direction of the fuel cell body 3, but the gas flow path 31 may extend in the short direction of the fuel battery cell body 3. In this case, the short direction of the fuel cell body 3 corresponds to the first direction of the present invention. One end of the fuel cell main body 3 in the short direction is a base end and is supported by the manifold 20. In addition, the other end portion in the short direction of the fuel cell main body 3 becomes a tip portion, and the cap member 4 is attached.

Modification 10
In the above embodiment, the cross-sectional shape of the narrowed portion 421 in the protruding portion 42 of the cap member 4 is rectangular, but the cross-sectional shape of the narrowed portion 421 is not limited to this. For example, as shown in FIG. 16, the cross-sectional shape of the narrowed portion 421 may be a semicircular shape, or may be another shape.

Modification 11
In the above embodiment, each narrowed portion 421 is formed on the main surface of the protruding portion 42, but the position where each narrowed portion 421 is formed is not limited to this. For example, as shown in FIG. 17, the pair of narrowed portions 421 may be formed on the side surface of the protruding portion 42. In this case, the pair of narrowed portions 421 are recessed in the width direction of the fuel cell 10 so as to approach each other.

3: Fuel cell main body 31: Gas flow path 32: Base end portion 33: Tip end portion 4: Cap member 41: Heat conduction portion 42: Projection portion 43: Combustion portion 431: Gas discharge port 44: Wall portion 441: Protrusion portion 45: boundary 10: fuel cell 20: manifold 100: cell stack device

Claims (9)

A fuel cell main body having a gas flow path, a base end portion serving as a supply side of the gas flow path, and a distal end section serving as a discharge side of the gas flow path;
A cap member attached to the tip of the fuel cell body and having a gas outlet;
With
The cap member has a wall portion disposed at a distance from the gas discharge port along an outer peripheral edge of the gas discharge port.
Fuel cell.
The wall portion is composed of a plurality of protrusions.
The fuel battery cell according to claim 1.
The wall portion extends intermittently along the outer peripheral edge of the gas outlet.
The fuel battery cell according to claim 1 or 2.
The cap member is
A cylindrical heat conduction portion covering the outer peripheral surface of the tip portion of the fuel cell body; and
A cylindrical protrusion extending from the heat conducting portion along a first direction in which the gas flow path extends;
A combustion section arranged to close the protrusion and having the gas outlet;
Having
The fuel cell according to any one of claims 1 to 3.
The heat conducting portion is longer than the protruding portion in the first direction.
The fuel battery cell according to claim 4.
The boundary part between the combustion part and the protruding part has a chamfered shape,
The fuel battery cell according to claim 4 or 5.
  The distance between the wall portion and the outer peripheral edge of the gas discharge port is 0.1 to 2 mm.
The fuel cell according to any one of claims 1 to 6.
  The height of the wall is 10 to 1000 μm.
The fuel cell according to any one of claims 1 to 7.
The fuel cell according to any one of claims 1 to 8 ,
A manifold that supports the base end of the fuel cell body;
A cell stack device.

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