JP2010103009A - Internally modified solid oxide fuel cell, and fuel cell system - Google Patents

Abstract

In an internal reforming solid oxide fuel cell, the use amount of a reforming catalyst and an electronic conductive material is suppressed.
An internal reforming solid oxide fuel cell includes a cathode, an anode 12, a solid oxide electrolyte 11 sandwiched between the cathode and the anode 12, and a current collector 16 provided in contact with the anode. Prepare. The current collector 16 includes a catalyst current collecting element 61 in which a film containing a reforming catalyst for a reaction for generating hydrogen from a hydrocarbon and an electron conductive material is formed on the surface of the base material. The base material of the catalyst current collecting element 61 is formed of, for example, the same material as the solid oxide electrolyte 11.
[Selection] Figure 1

Description

  The present invention relates to an internal reforming solid oxide fuel cell and a fuel cell system.

  One new energy is hydrogen. As a field of utilization of hydrogen, a fuel cell that converts chemical energy into electric energy by electrochemically reacting hydrogen and oxygen has attracted attention. Fuel cells have high energy use efficiency and are being developed as large-scale distributed power sources, household power sources, and mobile power sources.

  Fuel cells are classified into a solid polymer type, a phosphoric acid type, a molten carbonate type, a solid oxide type, and the like depending on the temperature range and the type of material and fuel used. Among these, from the viewpoint of efficiency, a solid oxide fuel cell (SOFC) that uses a solid oxide electrolyte and obtains electric energy through an electrochemical reaction has attracted attention.

  A fuel cell is an electrochemical cell including an electrolyte and an electrode. The solid oxide electrolyte used in SOFC has oxygen ion conductivity and is generally formed using dense stabilized zirconia. In addition, a perovskite oxide, a ceria-based solid solution, or the like may be used as an electrolyte material having better oxygen ion conductivity than stabilized zirconia.

The SOFC electrode is divided into a fuel electrode and an air electrode. At the fuel electrode, H ₂ that is a fuel gas and oxygen ions that have moved inside the electrolyte react electrochemically to generate H ₂ O and electrons (e ⁻ ). In the air electrode, for example, oxygen in the air takes in electrons (e ⁻ ), and oxygen ions are generated by an electrochemical reaction. Oxygen ions generated at the air electrode move to the electrolyte.

  Generally, for example, a mixed sintered body (cermet) of a metal and a solid oxide such as Ni—YSZ (yttria stabilized zirconia) or Ni—ScSZ (scandia stabilized zirconia) is used for the fuel electrode. In some cases, for example, Ni, Co, Fe, Ni—Fe, Ni—Mg, Pt, or the like, a single metal or a mixture of a plurality of metals such as an alloy may be used for the fuel electrode.

  For the air electrode, for example, perovskite oxides such as LaSrMn oxides, LaSrCo oxides, LaSrCoFe oxides, LaSrFe oxides, and oxides in which partial sites thereof are substituted are generally used. In addition, a mixture with a solid oxide used for an electrolyte such as LSM-YSZ, LSM-ScSZ, LSC-SDC, LSC-GDC, or the like may be used for the air electrode.

  In such an electrochemical cell, an electrolyte and an electrode are laminated using an electrolyte or an electrode as a support. For example, when an electrolyte is used as a support, an air electrode layer and a fuel electrode layer are formed on both surfaces of a dense electrolyte substrate having a certain degree of strength. The thickness of the electrode layer is generally about several tens of μm.

  When an electrode is used as a support, a dense electrolyte layer is formed on the surface of a porous electrode substrate, and another electrode layer, that is, an air electrode when the substrate is a fuel electrode, is formed thereon. The The thickness of the electrolyte layer is generally about several to several tens of μm.

  In SOFC, it is possible to generate electricity by directly introducing hydrocarbon fuel or coal gasification gas in addition to hydrogen. In general, these fuels are converted into a fuel containing hydrogen using a reformer before being supplied to the fuel electrode and then introduced into the fuel electrode, or directly into the fuel electrode. In some cases, a reforming reaction is performed at the fuel electrode, and power is generated while being converted to a fuel containing hydrogen. The former is called an external reforming method, and the latter is called an internal reforming method.

  Metal components such as Ni, Fe, and Co, which are constituent elements of the fuel electrode, also have a reforming catalytic action that reforms a hydrocarbon fuel into a fuel containing hydrogen. When an electrode is used as a support, a cell using a fuel electrode as a support contains a large number of metal components having a reforming catalytic action such as Ni. For this reason, it is considered suitable for the internal reforming method, but depending on the conditions, the reforming may not proceed sufficiently. On the other hand, in the case of an electrolyte-supported cell, a metal having a reforming catalytic action such as Ni exists only in a thin electrode layer (several tens of μm), and the reforming may not sufficiently proceed in the internal reforming method. .

  Patent Document 1 discloses a method of using Ni fibers or the like as a current collector and imparting a modification action to the current collector. However, Ni fibers have a high possibility of deterioration of the modification effect and the current collecting function due to repeated redox. Therefore, an electrode having a high reforming catalytic action has been developed. Further, in Patent Document 2 and the like, prevention of cracking of hydrocarbon fuel is studied.

When the current collector is made of only Ni, the thermal expansion coefficient difference from the electrolyte or electrode material is large, so that problems such as breakage are likely to occur. Therefore, Patent Document 3 discloses a method of reducing a difference in thermal expansion coefficient by using a cermet material as a current collector material.
JP-A-3-283266 JP 2007-311318 A JP-A-8-17453

  For example, in an SOFC using an electrolyte-supported cell, if a hydrocarbon-based fuel or the like is internally reformed at the fuel electrode, the reforming effect at the fuel electrode may be low. If the current collecting material has a reforming effect, it is necessary to deteriorate due to repeated oxidation-reduction or to relax the difference in thermal expansion coefficient from other constituent materials.

  Further, the catalyst contributes to the reaction only at the portion in contact with the reactant. For this reason, the area | region inside the particle | grains of a catalyst does not contribute to reaction, but is a useless part as a catalyst. However, Patent Document 1 and the like do not disclose a method for reducing such a useless portion.

  Accordingly, an object of the present invention is to suppress the use amount of the reforming catalyst and the electronically conductive substance in the internal reforming solid oxide fuel cell.

  In order to achieve the above object, the present invention provides an internal reforming solid oxide fuel cell in which a cathode, an anode, a solid oxide electrolyte sandwiched between the cathode and the anode, and hydrogen from hydrocarbons. And a current collector comprising a catalyst current collector element formed on a surface of a base material and a current collector provided in contact with the anode. And

  The present invention also provides a fuel cell system having a cathode, an anode, a solid oxide electrolyte sandwiched between the cathode and the anode, a reforming catalyst for generating hydrogen from hydrocarbons on the surface, and electronic conductivity. An internal reforming solid oxide fuel cell having a current collector made of a catalyst current collecting element having a coating containing a substance and provided in contact with the anode, and containing a hydrocarbon in the anode And a fuel supply device for supplying hydrocarbon fuel.

  ADVANTAGE OF THE INVENTION According to this invention, the usage-amount of a reforming catalyst and an electronically conductive substance can be suppressed in an internal reforming type solid oxide fuel cell.

  An embodiment of an internal reforming solid oxide fuel cell according to the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or similar structure, and the overlapping description is abbreviate | omitted.

[First Embodiment]
FIG. 2 is a block diagram of a fuel cell system using the first embodiment of the internal reforming solid oxide fuel cell according to the present invention.

  The fuel cell system according to the present embodiment includes an internal reforming solid oxide fuel cell 30, a fuel supply device 31, and an oxygen supply device 32. In this fuel cell system, a fuel supply device 31 supplies a hydrocarbon-based fuel containing hydrocarbons to an internal reforming solid oxide fuel cell 30, and an oxygen supply device 32 provides an internal reforming solid oxide fuel. When oxygen is supplied to the battery 30, the internal reforming solid oxide fuel cell 30 generates power. The electric power generated by the internal reforming solid oxide fuel cell 30 is consumed by an external load 33 connected to the internal reforming solid oxide fuel cell 30.

  FIG. 3 is a perspective view of a state in which the internal reforming solid oxide fuel cell according to the present embodiment is disassembled.

  The internal reforming solid oxide fuel cell 30 is formed by stacking a plurality of plate-like single cells 17. FIG. 3 is a diagram in which a part of the internal reforming solid oxide fuel cell 30 to be stacked is extracted and components are separated from each other in the stacking direction. Between the constituent members of the internal reforming solid oxide fuel cell 30, a sealing material for preventing gas leakage and entry and an insulating material for electrical insulation are provided as necessary. It is done.

  The internal reforming solid oxide fuel cell 30 has current collectors 15 and 16 sandwiching the single cell 17 from both surfaces, and the single cell 17 and current collectors 15 and 16 from both surfaces. And a separator 14 to be sandwiched. The current collectors 15 and 16 are both made of a conductive material and are formed in layers so that gas can pass through.

  The separator 14 is formed in a plate shape with a conductive material. The single cell 17 is electrically connected by current collectors 15 and 16 and a separator 14. In the separator 14, a through fuel channel 21 and a through oxygen channel 23 are formed. The penetrating fuel passage 21 and the penetrating oxygen passage 23 are spaces in which regions extending along opposing sides penetrate each other in the plate thickness direction of the separator 14. On one surface of the separator 14, a groove-like fuel channel 22 is formed between the pair of through fuel channels 21. On the surface of the separator 14 opposite to the side on which the groove-like fuel passage 22 is formed, a groove-like oxygen passage 24 is formed between the pair of penetrating oxygen passages 23. Since the groove-like fuel channel 22 and the groove-like oxygen channel 24 are provided in the separator 14, the reaction gas is efficiently supplied to the anode 12 and the cathode 13.

  FIG. 4 is a cross-sectional view of a single cell in the present embodiment.

  The single cell 17 according to the present embodiment has a plate-like solid oxide electrolyte 11 as a support, and both sides thereof are sandwiched between a cathode 13 and an anode 12. For example, the cathode 13, the solid oxide electrolyte 11, and the anode 12 are all formed in layers.

The solid oxide electrolyte 11 is formed using, for example, stabilized zirconia, perovskite oxide, or ceria (CeO ₂ ) electrolyte solid solution. Stabilized zirconia is, for example, zirconia in which Y ₂ O ₃ , Sc ₂ O ₃ , Yb ₂ O ₃ , Gd ₂ O ₃ , Nd ₂ O ₃ , CaO, MgO or the like is dissolved as a stabilizer. Examples of the perovskite oxide include LaSrGaMg oxide, LaSrGaMgCo oxide, LaSrGaMgCoFe oxide, LaSrGaMgCoFe oxide, and the like. Examples of the ceria (CeO ₂ ) -based electrolyte solid solution include ceria-based solid solutions in which Sm ₂ O ₃ , Gd ₂ O ₃ , Y ₂ O ₃ , La ₂ O _{3 and the} like are dissolved. In addition, you may use electrolytes other than these.

  The cathode 13 includes, for example, LaSrMn oxide (hereinafter referred to as LSM), LaSrCo oxide (hereinafter referred to as LSC), LaSrCoFe oxide (hereinafter referred to as LSCF), LaSrFe oxide (hereinafter referred to as LSF), LaSrMnCo, Oxide (hereinafter referred to as LSMC), LaSrMnCr oxide (hereinafter referred to as LSMC), LaCoMn oxide (hereinafter referred to as LCM), LaSrCu oxide (hereinafter referred to as LSC), LaSrFeNi oxide (hereinafter referred to as LSFN) ), LaNiFe oxide (hereinafter referred to as LNF), LaBaCo oxide (hereinafter referred to as LBC), LaNiCo oxide (hereinafter referred to as LNC), LaSrAlFe oxide (hereinafter referred to as LSAF), LaSrCoNiCu oxidation Product (hereinafter referred to as LSCNC), LaSrFe iCu oxide (hereinafter referred to as LSFNC), LaNi oxide (hereinafter referred to as LN), GdSrCo oxide (hereinafter referred to as GSC), GdSrMn oxide (hereinafter referred to as GSM), PrCaMn oxide (hereinafter referred to as LSM) PCaM), PrSrMn oxide (hereinafter referred to as PSM), PrBaCo oxide (hereinafter referred to as PBC), SmSrCo oxide (hereinafter referred to as SSC), NdSmCo oxide (hereinafter referred to as NSC), BiSrCaCu Oxide (hereinafter referred to as BSCC), BaLaFeCo oxide (hereinafter referred to as BLFC), BaSrFeCo oxide (hereinafter referred to as BSFC), YSrFeCo oxide (hereinafter referred to as YLFC), YCuCoFe oxide (hereinafter referred to as YCCF) And YBaCu oxide (hereinafter referred to as YBC). The cathode 13 may be a mixture with an electrolyte material, for example, LSM-YSZ, LSCF-SDC, LSCF-GDC, LSCF-YDC, LSCF-LDC, LSCF-CDC, LSM-ScSZ, LSM-SDC, LSM-GDC. Etc. may be formed. Furthermore, for example, components such as Pt, Ru, Au, Ag, and Pd may be added to the cathode 13.

  FIG. 1 is an enlarged cross-sectional view of the vicinity of the anode in the present embodiment.

  The anode 12 is formed in layers on the surface of the solid oxide electrolyte 11 using anode particles 60 that are, for example, a mixed sintered body (cermet) of metal and solid oxide. As the cermet, for example, Ni—YSZ, Ni—ScSZ, Ni—SDC, Ni—GDC, Ni—YDC, and the like are used. Moreover, you may add components, such as Fe, Co, Cu, Mg, Al, Pt, Ru, Au, to such a cermet. Or you may use the cermet which uses Fe, Co, Cu, Mg, Al, Pt, Ru, Au, etc. as a main constituent material. Moreover, you may use the metal containing a noble metal independently as an electrode. For example, the anode 12 may be formed of a simple substance such as Ni, Fe, Co, Cu, Mg, Al, Pt, Ru, or Au, an alloy, or a mixture.

  A layer of a current collector 16 is formed on the surface of the anode 12. The current collector 16 is an aggregate of the catalyst current collecting elements 61.

  FIG. 5 is a cross-sectional view of the catalyst current collecting element in the present embodiment.

  The catalyst current collecting element 61 is a particle in which a coating 81 containing a reforming catalyst and an electronic conductive material is formed on the surface of a base material 91. The reforming catalyst is a catalyst such as Ni in a reforming reaction that generates hydrogen from a hydrocarbon. Further, the electron conductive substance is a substance having electronic conductivity such as Ni. The current collector 16 is provided in contact with the anode 12.

  The catalyst current collecting element 61 includes, for example, a plating method, PVD method, CVD method, electrophoresis method, slurry coating method, sputtering method, plasma spray method, ion plating method, flame spray method, plasma jet torch method, EVD method, Formed by. Alternatively, the catalyst current collecting element 61 can be formed by a mechanical action such as compression, friction, or shearing force.

  It is desirable that the base 91 of the catalyst current collecting element 61 has heat resistance and is stable. Examples of the reforming catalyst and the electronic conductive material contained in the coating 81 include simple metals such as Ni, Fe, Co, Mg, Ti, Cu, Al, Pt, Au, Ag, Pd, and Ru, a mixture thereof, or These alloys can be used. Further, oxide ceramics such as perovskite oxides or non-oxide ceramics may be used as the reforming catalyst and the electronic conductive material contained in the coating 81.

  Further, the coating 81 of the catalyst current collecting element 61 may be a single layer or a plurality of layers of two or more layers. The surface of the catalyst current collecting element 61 does not need to be completely covered with the coating 81, and may be in the form of dots or spots.

  FIG. 6 is a photomicrograph of particles in which an Ag coating is formed on the surface of YSZ as a base material.

  The particles in FIG. 6 have YSZ particles having a diameter of about 15 μm as a base material, and an Ag film of about 1 μm is formed on the surface thereof. Such particles can be used as the catalyst current collecting element 61.

  In such a fuel cell system, the hydrocarbon-based fuel supplied to the internal reforming solid oxide fuel cell 30 by the fuel supply device 31 is sent to the groove-like fuel channel 22 through the through fuel channel 21. It is done. The hydrocarbon fuel that has reached the groove-like fuel flow path 22 comes into contact with the catalyst current collecting element 61 of the current collector 16. Since the coating 81 containing the reforming catalyst of the reforming reaction for generating hydrogen from hydrocarbon is formed on the surface of the catalyst current collecting element 61, the inside of the catalyst current collecting element 61 using the hydrocarbon fuel in contact with the catalyst current collecting element 61. A reforming reaction occurs. Hydrogen produced by this internal reforming reaction is supplied to the anode 12. The oxygen supply device 32 supplies a gas containing oxygen such as air to the internal reforming solid oxide fuel cell 30. The gas containing oxygen is sent to the groove-like oxygen channel 24 through the through oxygen channel 23. Oxygen that has reached the groove-like oxygen flow path 24 comes into contact with the cathode 13.

  By supplying hydrogen to the anode 12 and oxygen to the cathode 13 in this way, the internal reforming solid oxide fuel cell 30 generates power. Since the catalyst current collecting element 61 of the current collector 16 is formed with the coating 81 containing the electron conductive material, the current generated by the power generation flows through the current collector 16.

  Since the reforming catalyst does not contribute to the internal reforming reaction unless it comes into contact with the hydrocarbon-based fuel, even if the reforming catalyst is contained in the catalyst current collecting element 61, the function as a catalyst is hardly exhibited. However, in the present embodiment, the coating 81 containing the reforming catalyst and the electronic conductive material is formed on the surface of the catalyst current collecting element 61. For this reason, the usage-amount of a reforming catalyst can be suppressed, without impairing the function as a catalyst almost. Moreover, the usage-amount of an electronic conductive substance can be suppressed, ensuring electronic conductivity.

  Furthermore, when a catalyst or a current collecting element formed entirely of a metal such as Ni is used, when the high operating temperature and the low temperature during the stop are repeatedly experienced, the oxidation reaction and the reduction reaction may be repeatedly experienced. When the oxidation reaction and the reduction reaction are repeatedly experienced, the volume change associated with these reactions is repeatedly experienced, and cracks or the like may occur, and the soundness may not be maintained. However, in the present embodiment, since a metal such as Ni is used only on the surface, even if the oxidation reaction and the reduction reaction are repeatedly experienced, the volume change is small and there is little possibility that the soundness is impaired.

  Ni and Ru are preferable as a reforming catalyst and an electronic conductive material contained in the coating 81 because they have a high reforming effect. Moreover, since Ag has very high electronic conductivity, it is preferable that Ag is contained in the coating film 81.

  Further, the base 91 of the catalyst current collecting element 61 is preferably formed of a material having a thermal expansion coefficient closer to that of the solid oxide electrolyte 11 than the catalyst material and the electronic conductive material contained in the coating 81. Furthermore, it is preferable to use a material having the same thermal expansion coefficient as that of the solid oxide electrolyte 11. The thermal expansion of the catalyst current collecting element 61 greatly depends on the thermal expansion coefficient of the base material 91 that occupies most of the volume of the catalyst current collecting element 61. For this reason, if the thermal expansion coefficient of the base material 91 and the solid oxide electrolyte 11 is approximately the same, the difference in thermal expansion between the layer of the current collector 16 and the solid oxide electrolyte 11 can be reduced. By reducing the difference in thermal expansion, it is possible to suppress the peeling of the layers of the current collector 16 and the occurrence of cracks.

  Therefore, the base material 91 of the catalyst current collecting element 61 is made of, for example, the same material as that of the solid oxide electrolyte 11. When YSZ is used for the solid oxide electrolyte 11, YSZ is used as the base material 91. Alternatively, when ScSZ is used for the solid oxide electrolyte 11, ScSZ is used as the substrate 91, and when a ceria-based electrolyte material such as GDC or SDC is applied to the solid oxide electrolyte 11, the ceria-based electrolyte material is used as the substrate 91. When a lanthanum garade material is applied to the solid oxide electrolyte 11, a lanthanum garade material is used as the substrate 91. As a result, the thermal expansion of the layers of the solid oxide electrolyte 11 and the current collector 16 can be made substantially the same. Further, when the base material 91 is formed of a ceria-based electrolyte material such as GDC or SDC, carbon deposition can be suppressed, and a high reforming effect can be obtained in an internal reforming solid oxide fuel cell.

[Second Embodiment]
FIG. 7 is a sectional view of a single cell in the second embodiment of the internal reforming solid oxide fuel cell according to the present invention.

  The single cell 17 of the present embodiment has a plate-like anode 12 as a support, and a solid oxide electrolyte 11 and a cathode 13 are laminated on the surface thereof. Even in the internal reforming solid oxide fuel cell using the single cell 17, a layer of the current collector 16 (see FIG. 1) is formed on the surface of the anode 12 as in the first embodiment. Thereby, the usage-amount of a reforming catalyst and an electronic conductive substance can be suppressed.

  In this embodiment, since the anode 12 is used as a support, the thermal expansion of the anode 12 is dominant as the thermal expansion of the single cell 17. Therefore, it is preferable to use a material having a thermal expansion coefficient similar to that of the anode 12 as the base material 91 of the catalyst current collecting element 61 of the current collector 16.

[Third Embodiment]
FIG. 8 is a sectional view of a single cell in the third embodiment of the internal reforming solid oxide fuel cell according to the present invention.

  In the single cell 17 of the present embodiment, a reaction suppression layer 18 is provided between the solid oxide electrolyte 11 and the cathode 13. The reaction suppression layer 18 needs to have a dense structure or a close-packed structure. Even in the internal reforming solid oxide fuel cell using the single cell 17, a layer of the current collector 16 (see FIG. 1) is formed on the surface of the anode 12 as in the first embodiment. Thereby, the usage-amount of a reforming catalyst and an electronic conductive substance can be suppressed.

  Depending on the selection of the electrolyte material that forms the solid oxide electrolyte 11 and the electrode material that forms the cathode 13 or the like, the reactivity between the electrolyte material and the electrode material may be high. In such a case, the reaction between the electrolyte material and the electrode material can be suppressed by providing the reaction suppression layer 18 between the solid oxide electrolyte 11 and the cathode 13. A reaction suppression layer may be introduced.

[Fourth Embodiment]
FIG. 9 is a perspective view showing a single cell together with a cross section in a fourth embodiment of an internal reforming solid oxide fuel cell according to the present invention.

  The single cell 17 according to the present embodiment is obtained by stacking a solid oxide electrolyte 11 and a cathode 13 on the outer surface of a cylindrical anode 12 as a support. An anode active layer may be provided between the anode support and the electrolyte layer. A reaction suppression layer may be provided between the solid oxide electrolyte 11 and the cathode 13.

  When such a single cell 17 is used, the internal space of the cylindrical anode 12 serves as a fuel flow path, so there is no need to separately form a fuel flow path. Further, since oxygen existing outside is supplied to the cathode 13, it is not necessary to separately form an oxygen flow path, and it is not necessary to provide an oxygen supply device 32 (see FIG. 2).

  Even in the internal reforming solid oxide fuel cell using this single cell 17, a layer of the current collector 16 (see FIG. 1) is formed on the surface of the anode 12 as in the first embodiment. Thereby, the usage-amount of a reforming catalyst and an electronic conductive substance can be suppressed.

[Fifth Embodiment]
FIG. 10 is an enlarged cross-sectional view of the vicinity of the anode in the fifth embodiment of the internal reforming solid oxide fuel cell according to the present invention.

  In the present embodiment, an anode 19 with a current collector is provided in place of the layer of the current collector 16 (see FIG. 1) and the anode 12 (see FIG. 1) in the first embodiment. The anode 19 with a current collector contains a mixture of anode particles 60, particulate catalyst current collector elements 61, and fibrous catalyst current collector elements 62. The fibrous catalyst current collecting element 62 has a particulate catalyst current collecting element in which a coating 81 (see FIG. 5) containing a reforming catalyst and an electronic conductive material is formed on the surface of a substrate 91 (see FIG. 5). It has the same cross-sectional shape as 61 (see FIG. 5).

  Even when such a fibrous catalyst current collecting element 62 is used, the amount of the reforming catalyst and the electron conductive material used can be suppressed as in the case of the particulate catalyst current collecting element 61. Only one of the particulate catalyst current collecting element 61 and the fibrous catalyst current collecting element 62 may be used.

  By mixing the catalyst current collecting elements 61 and 62 and the anode particles 60, the moving distance of the hydrogen generated by the internal reforming reaction to the anode particles 60 is shortened. In addition, the overall thickness of the current collector and the anode can be reduced.

  The density of the catalyst current collecting elements 61 and 62 in the current-collecting anode 19 may be changed from the solid oxide electrolyte 11 toward the separator 14. For example, in the vicinity of the separator 14 where more hydrocarbon fuel is present, the internal reforming reaction can be more efficiently advanced by increasing the density of the catalyst current collecting elements 61 and 62.

[Sixth Embodiment]
FIG. 11 is an enlarged cross-sectional view of the vicinity of the anode in the sixth embodiment of the internal reforming solid oxide fuel cell according to the present invention.

  In the present embodiment, the catalyst current collecting element 61 is also filled in the groove-like fuel flow path 22 of the separator 14. At this time, it is necessary to secure a space through which the hydrocarbon-based fuel can pass in the groove-like fuel flow path 22.

  In such an internal reforming solid oxide fuel cell, for example, the reforming catalyst is present in the groove-like fuel flow path 22 of the separator 14 in which more hydrocarbon fuel is present. improves. Further, since the catalyst current collecting element 61 is also in contact with the separator 14 in the grooved fuel flow path 22, the current collecting area is increased and the internal resistance of the solid oxide fuel cell is reduced.

[Seventh Embodiment]
FIG. 12 is an enlarged cross-sectional view of the vicinity of the anode in the seventh embodiment of the internal reforming solid oxide fuel cell according to the present invention.

  In this embodiment, the grooved fuel flow path 22 of the separator 14 is filled with the reforming catalyst particles 42. At this time, it is necessary to secure a space through which the hydrocarbon-based fuel can pass in the groove-like fuel flow path 22. In such an internal reforming solid oxide fuel cell, for example, the reforming catalyst is present in the groove-like fuel flow path 22 of the separator 14 in which more hydrocarbon fuel is present. improves.

  As the reforming catalyst particles 42, for example, those that have been used in chemical plant or fuel cell reformers are used. Thereby, the reliability of the solid oxide fuel cell can be improved.

  Even in such an internal reforming type solid oxide fuel cell, at least in the layer of the current collector 16, it is not necessary to use the reforming catalyst and the electronic conductive material inside the base material. In addition, the amount of the electronic conductive substance used can be suppressed.

[Eighth Embodiment]
FIG. 13 is an enlarged cross-sectional view of the vicinity of the anode in the eighth embodiment of the internal reforming solid oxide fuel cell according to the present invention.

  In the present embodiment, the reformed catalyst particles 42 and the catalyst current collecting element 61 are filled in the groove-like fuel flow path 22 of the separator 14. At this time, it is necessary to secure a space through which the hydrocarbon-based fuel can pass in the groove-like fuel flow path 22. As the reforming catalyst particles 42, for example, those that have been used in chemical plant or fuel cell reformers are used.

  A commonly used reforming catalyst uses alumina or the like as a support, and therefore has very low conductivity. However, in the present embodiment, the current collecting effect can be improved by mixing such reforming catalyst particles 42 with the catalyst current collecting element 61.

[Ninth Embodiment]
FIG. 14 is an enlarged cross-sectional view of the vicinity of the anode in the ninth embodiment of the internal reforming solid oxide fuel cell according to the present invention.

  In the present embodiment, a layer of the current collector 16 is formed by the catalyst current collecting element 61 and the conductive particles 43. The conductive particles 43 are particles having a film formed on the surface with a substance having higher electronic conductivity than the catalyst current collecting element 61. For example, the catalyst current collecting element 61 is a particle having a film formed of Ni or Ru, and the conductive particle 43 is a particle having a film formed of Ag.

  Thus, the current collection effect can be enhanced by using the conductive particles 43. Instead of the conductive particles 43, a fibrous object having a surface coated with a substance having a high electronic conductivity may be used similarly to the fibrous catalyst current collecting element 62.

[Tenth embodiment]
FIG. 15 is an enlarged cross-sectional view of the vicinity of the anode in the tenth embodiment of the internal reforming solid oxide fuel cell according to the present invention.

  In the present embodiment, the conductive fuel 43 and the catalyst current collecting element 61 are filled in the groove-like fuel flow path 22 of the separator 14. At this time, it is necessary to secure a space through which the hydrocarbon-based fuel can pass in the groove-like fuel flow path 22. In such an internal reforming type solid oxide fuel cell, since the conductive particles 43 are also in contact with the separator 14 and the groove-like fuel flow path 22, the internal resistance is reduced.

[Eleventh embodiment]
FIG. 16 is a plan view of a catalyst current collecting element in an eleventh embodiment of an internal reforming solid oxide fuel cell according to the present invention.

  In the present embodiment, the catalyst current collecting element 61 is obtained by forming the coating 81 on the surface of the base material 91 by highly dispersing the reforming catalyst and the electronic conductive material. The shape of the catalyst current collecting element 61 may be particulate or fibrous.

  When the reforming catalyst and the electronically conductive substance are simply supported on the surface of the base material 91, especially at the vicinity of the contact portion of the particles at a high temperature required for the operation of the internal reforming solid oxide fuel cell. Aggregation may occur. However, such agglomeration is less likely to occur by highly dispersing the reforming catalyst and the electronic conductive material.

  Further, by highly dispersing the reforming catalyst and the electronic conductive material on the surface of the base material 91, the active area contributing to the reaction is increased, and the reforming effect can be improved.

[Other embodiments]
The above-described embodiments are merely examples, and the present invention is not limited to these. Moreover, it can also implement combining the characteristic of each embodiment.

1 is an enlarged cross-sectional view in the vicinity of an anode in a first embodiment of an internal reforming solid oxide fuel cell according to the present invention. 1 is a block diagram of a fuel cell system using a first embodiment of an internal reforming solid oxide fuel cell according to the present invention. FIG. 1 is an exploded perspective view of a first embodiment of an internal reforming solid oxide fuel cell according to the present invention. It is sectional drawing of the single cell in 1st Embodiment of the internal reforming type solid oxide fuel cell which concerns on this invention. It is sectional drawing of the catalyst current collection element in 1st Embodiment of the internal reforming type solid oxide fuel cell which concerns on this invention. It is a microscope picture of the particle | grains in which the coating film of Ag was formed in the surface using YSZ as a base material. It is sectional drawing of the single cell in 2nd Embodiment of the internal reforming type solid oxide fuel cell which concerns on this invention. It is sectional drawing of the single cell in 3rd Embodiment of the internal reforming type solid oxide fuel cell which concerns on this invention. It is a perspective view which shows the single cell in 4th Embodiment of the internal reforming type solid oxide fuel cell which concerns on this invention with a cross section. It is an expanded sectional view of the anode vicinity in the fifth embodiment of the internal reforming solid oxide fuel cell according to the present invention. It is an expanded sectional view of the anode vicinity in the sixth embodiment of the internal reforming solid oxide fuel cell according to the present invention. It is an expanded sectional view of the anode vicinity in the seventh embodiment of the internal reforming solid oxide fuel cell according to the present invention. It is an expanded sectional view of the anode vicinity in the eighth embodiment of the internal reforming solid oxide fuel cell according to the present invention. It is an expanded sectional view of the anode vicinity in the ninth embodiment of the internal reforming solid oxide fuel cell according to the present invention. It is an expanded sectional view of the anode vicinity in the tenth embodiment of the internal reforming solid oxide fuel cell according to the present invention. It is a top view of the catalyst current collection element in 11th Embodiment of the internal reforming type solid oxide fuel cell which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Solid oxide electrolyte, 12 ... Anode, 13 ... Cathode, 14 ... Separator, 15 ... Current collector, 16 ... Current collector, 17 ... Single cell, 18 ... Reaction suppression layer, 19 ... Anode with a current collector, DESCRIPTION OF SYMBOLS 21 ... Through fuel flow path, 22 ... Groove fuel flow path, 23 ... Through oxygen flow path, 24 ... Groove oxygen flow path, 30 ... Internal reforming type solid oxide fuel cell, 31 ... Fuel supply apparatus, 32 DESCRIPTION OF SYMBOLS ... Oxygen supply apparatus, 33 ... External load, 42 ... Reformed catalyst particle, 43 ... Conductive particle, 60 ... Anode particle, 61 ... Catalyst current collection element, 62 ... Catalyst current collection element, 81 ... Coating, 91 ... Base material

Claims (12)

A cathode,
An anode,
A solid oxide electrolyte sandwiched between the cathode and the anode;
A current collector provided in contact with the anode, including a catalyst current collecting element formed on the surface of the substrate with a coating containing a reforming catalyst for the reaction of generating hydrogen from hydrocarbons and an electron conductive material;
An internal reforming solid oxide fuel cell characterized by comprising:   2. The internal reforming according to claim 1, wherein the base material is formed of a material having a thermal expansion coefficient closer to the solid oxide electrolyte than any of the reforming catalyst and the electron conductive material. Type solid oxide fuel cell.   The internal reforming solid oxide fuel cell according to claim 2, wherein the base material is formed of the same material as the solid oxide electrolyte.   The internal reforming solid oxide fuel cell according to any one of claims 1 to 3, wherein the base material is made of a ceria-based electrolyte material.   5. The internal reforming solid oxide fuel cell according to claim 1, wherein both of the reforming catalyst and the electronically conductive material are Ni.   The internal reforming solid according to any one of claims 1 to 5, wherein the current collector includes a conductive element having a higher electronic conductivity of the coating than the catalyst current collecting element. Oxide fuel cell.   The internal reforming solid oxide fuel cell according to any one of claims 1 to 6, wherein the conductive element contains Ag.   A fuel flow path through which a hydrocarbon-containing fuel, which is a substance having electronic conductivity, has a separator formed to face the anode, and the current collector is provided between the separator and the anode. The internal reforming solid oxide fuel cell according to any one of claims 1 to 7, wherein the internal reforming solid oxide fuel cell is provided.   9. The internal reforming solid oxide fuel cell according to claim 8, wherein the catalyst current collecting element is also disposed in the fuel flow path.   10. The internal reforming solid oxide fuel cell according to claim 8, wherein the reforming catalyst is present on at least a surface and has a reforming catalyst element disposed in the fuel flow path. 11.   The internal reforming solid oxide fuel cell according to any one of claims 1 to 10, wherein the coating is formed in a highly dispersed state. A catalyst comprising a cathode, an anode, a solid oxide electrolyte sandwiched between the cathode and the anode, and a coating containing a reforming catalyst for generating hydrogen from hydrocarbons and a substance having electronic conductivity on the surface An internal reforming solid oxide fuel cell having a current collector made of a current collecting element and provided in contact with the anode;
A fuel supply device for supplying a hydrocarbon-based fuel containing hydrocarbons to the anode;
A fuel cell system comprising: