JP2015028888A - Fuel battery cell and fuel battery cell stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel battery cell capable of avoiding dispersion of power generation amount in a plain surface in an electrode of the fuel battery cell, and effectively performing power generation.SOLUTION: A fuel battery cell 111 has an air electrode 21, a fuel electrode and a solid electrolyte layer, and is arranged adjacent to a collector having a plurality of projections for current collection. Collector contact parts 37 capable of being in contact with a plurality of projections of the collector, are installed on a surface of the air electrode 21 in a dotted state. A conductive layer 138 is provided on the surface of the air electrode 21. The conductive layer 138 has a wire connection 140 that connects a contact pad part 139 in contact with projections 35 of a collector 27 at the air electrode and a contact pad part 139 of the collector contact part 37 adjacent to the collector 27 at the air electrode. The wire connection 140 is so formed as to be made denser from coarser the furtherer from an inflow side of reactive gas F1, A1 supplied along a plane direction of the air electrode 21 to an outflow side.

Description

  The present invention relates to a fuel battery cell configured as a flat plate member having a fuel electrode, an air electrode, and an electrolyte layer, and a fuel battery cell stack including the fuel battery cell.

  Conventionally, a solid oxide fuel cell (SOFC) including a solid electrolyte layer (solid oxide layer) is known as a fuel cell which is a kind of power generation device. This solid oxide fuel cell has a very high energy conversion efficiency of 50% or more and can be miniaturized, and therefore has been developed as a power source for household cogeneration systems and automobiles.

  Specifically, the solid oxide fuel cell includes a flat fuel cell in which a fuel electrode in contact with the fuel gas and an air electrode in contact with the oxidant gas are disposed on both sides of the solid electrolyte layer (for example, Patent Documents 1 to 3). The fuel gas is for generating hydrogen, and the oxidant gas is for generating oxygen. Then, when hydrogen and oxygen react via a solid electrolyte layer (power generation reaction), DC power is generated with the air electrode as the positive electrode and the fuel electrode as the negative electrode.

  In the solid oxide fuel cell disclosed in Patent Document 1, conductive strips are continuously provided on the surfaces of the fuel electrode and the air electrode. In this fuel cell, electrons flow parallel to the electrodes through the conductive strips. That is, the conductive strip functions as a current collector and the resistance in the planar direction is reduced. For this reason, the electric current generated at each electrode flows in a direction parallel to the electrode without voltage loss.

  In the solid oxide fuel cell disclosed in Patent Document 2, a conductive electrode that joins the air electrode and the air electrode side current collector between the air electrode and the air electrode side current collector in the fuel cell. The adhesion layer is formed in a lattice shape. By providing this adhesion layer, the air electrode and the air electrode side current collector are reliably in contact with each other, and their contact resistance can be kept low.

  By the way, in the fuel cell described above, when the shape of the fuel cell is a flat plate and the reaction gas flow is carried out from the end surface of the fuel cell, the flow of the reaction gas (fuel gas and oxidant gas) (gas flow) ) May be crossflow (cross flow), counterflow (counterflow), coflow (parallel flow), or the like. When power generation is performed using these gas flows, since the reaction gas is used by the power generation reaction, the gas concentration is not uniform in the cell plane (in the plane of each electrode of the fuel cell). That is, on the outflow side (downstream portion) compared to the inflow side (upstream portion) of the reaction gas, the oxygen concentration decreases at the air electrode, and the fuel concentration (concentration of hydrogen or the like) decreases at the fuel electrode. Due to the oxygen concentration difference and the hydrogen concentration difference between the upstream and downstream of the reaction gas, a large difference occurs in the current density (oxygen ion conductivity) in the cell plane. As a result, the temperature distribution is caused by the difference in the amount of power generation in the cell surface, and stress is generated in the fuel cell, which makes it easy for the fuel cell to break or the performance of the fuel cell deteriorates quickly. Occur.

  Patent Document 3 discloses a solid oxide fuel cell configured to suppress the occurrence of temperature distribution in the cell plane by changing the arrangement interval of the current collector according to the flow of the reaction gas. Yes. In this fuel cell, a plurality of fuel cells (power generation unit) and interconnectors are stacked to constitute a fuel cell stack. On the surface of the interconnector, a plurality of ribs (projections) functioning as current collectors are disposed along the direction of the gas flow path. And the arrangement | positioning space | interval of these ribs is set so that it may become large gradually toward the outflow side from a gas inflow side. In this case, since the gas permeation area is small on the gas inflow side, the amount of power generation on the gas inflow side is kept low, and the heat generation amount is reduced. On the other hand, since the gas permeation area increases on the gas outflow side, the amount of power generation on the gas outflow side increases and the heat generation amount also increases. As a result, the difference in the amount of current (ion conduction amount) in the surface is suppressed, and the generation of the temperature distribution in the cell surface is suppressed.

JP-A-4-298963 JP 2009-99308 A JP-A-11-297341

  However, in the fuel cell of Patent Document 3, since the number of ribs is large on the gas inflow side, when power is actually generated, the amount of power generation increases on the gas inflow side. On the other hand, since the number of ribs is small on the gas outflow side, the power generation amount decreases. As a result, power generation is concentrated on the gas inflow side, and heat generation accompanying power generation is large on the gas inflow side and small on the gas outflow side. The problem that becomes. That is, in the fuel cell of Patent Document 3, although the power generation area (reacting power generation reaction) through which the reaction gas flows is adjusted, the adjustment is performed by the current collector (conductor). Many electrons try to flow on the gas inflow side where the number of ribs is increased when connected. Therefore, a substantial effective power generation area (considering power generation reaction and current) increases, and a partial increase in current density occurs in the cell plane. As a result, the effective power generation distribution (temperature distribution) in the single cell plane (including the current collector and the like) becomes large. Moreover, since it is necessary to change the shape of the current collector, the processing cost increases.

  Incidentally, in the fuel cell of Patent Document 1, conductive strips are uniformly formed on the surface of the air electrode. For this reason, it cannot be avoided that the power generation amount varies in the cell plane due to the flow of the reaction gas and the power generation amount becomes non-uniform (that is, power generation amount variation). Further, in the fuel cell of Patent Document 2, conductive adhesion layers are regularly provided in a lattice shape within the surface of the air electrode, and these adhesion layers are formed using the same conductive material. For this reason, the variation in the amount of power generation in the cell plane due to the flow of the reaction gas cannot be avoided.

  The present invention has been made in view of the above problems, and an object of the present invention is to eliminate a variation in power generation amount (due to a power generation reaction and current collection) in a plane of an electrode, and to efficiently perform power generation. To provide a cell. Another object is to provide a fuel cell stack that can efficiently generate power using the fuel cell.

  And as a means (means 1) for solving the above-mentioned problem, a flat plate member arranged adjacent to a current collector having a plurality of projections for current collection and having a fuel electrode, an air electrode and an electrolyte layer A fuel cell comprising a current collector contact portion configured to be in the form of scattered dots on the surface of at least one of the fuel electrode and the air electrode. And a conductive layer provided on the surface of the electrode, wherein the conductive layer is provided in an inner region of each of the plurality of current collector contact portions, and a contact with which a projection of the current collector contacts It has a pad part, and it is provided so that it may protrude outside the said collector contact part from the connection part provided so that it may connect between the said contact pad parts of the said adjacent collector contact part and the said contact pad part At least one of the pad extensions Has a better, at least one of the connecting portion and the pad extension portion, there is a fuel cell, characterized by being formed so as to have a density.

  Therefore, according to the invention described in the means 1, the current collector contact portions where the plurality of protrusions of the current collector can come into contact are set in the form of dots. Further, a conductive layer is provided on the surface of the electrode, and at least one of the connection portion and the pad extension portion constituting the conductive layer is formed so as to have a density. In a fuel cell, power generation occurs when electrons are transferred from the current collector to the electrode. Therefore, by forming a conductive layer having such a density on the electrode surface, there is a difference in current collection resistance in the fuel cell. Arise. That is, the conductive layer is set so as to increase the current collection resistance at a location where the concentration of the fuel gas and the oxidizing gas in the cell surface is high, such as the gas inflow side. On the other hand, the conductive layer is set so as to reduce the current collecting resistance at a location where the fuel gas and oxidizing gas concentrations in the cell surface are low, such as the gas outflow side. The current collecting resistance in the present invention is not an electric resistance of only the current collector, but a three-phase interface (interface between the reaction gas, the electrode, and the solid electrolyte layer) through the current collector and the electrode (fuel electrode and air electrode). ) Refers to the electrical resistance. Therefore, the difference in current collection resistance in the fuel cell as described above eliminates the variation in power generation amount in the plane of the fuel cell, reduces the temperature distribution difference during power generation, Early deterioration of cell characteristics can be avoided. In the present invention, the power generation amount includes both the power generation reaction and the power generation resistance obtained by the power generation reaction. Further, in the fuel cell of the present invention, the protrusions of the current collector are arranged in the form of dots with a predetermined interval, and the current collector arrangement interval according to the flow of the reaction gas as in the prior art There is no need to change the shape. For this reason, in the fuel cell, a sufficient flow rate of the reaction gas supplied to each electrode can be ensured, and power generation can be performed efficiently. Furthermore, since the processing cost accompanying the shape change of a collector is unnecessary, the manufacturing cost of a fuel cell can be held down.

  At least one of the connection part and the pad extension part in the conductive layer has an area ratio per unit area in the surface of the electrode from the inflow side to the outflow side of the reaction gas supplied along the planar direction of the electrode. Formed from coarse to dense. In the fuel cell, when the conductive layer is formed in this manner, a difference in current collection resistance occurs in the fuel cell. That is, the conductive layer is set so as to increase the current collection resistance at a location where the concentration of the fuel gas and the oxidizing gas in the cell surface is high, such as the gas inflow side. On the other hand, the conductive layer is set so as to reduce the current collecting resistance at a location where the fuel gas and oxidizing gas concentrations in the cell surface are low, such as the gas outflow side. As a result, a difference in power generation amount between the inflow side and the outflow side of the reaction gas is less likely to occur, and variations in the power generation amount in the plane of the fuel cell can be eliminated, thereby avoiding cell cracks and early deterioration of cell characteristics. be able to.

  The individual area of at least one of the connection part and the pad extension part in the conductive layer may be larger on the outflow side than on the reaction gas inflow side. In the fuel cell, when the conductive layer is formed in this way, a difference in the amount of power generation between the inflow side and the outflow side of the reaction gas is unlikely to occur, and cell cracks and early deterioration of cell characteristics can be avoided.

  The individual width (thickness) of at least one of the connection part and the pad extension part in the conductive layer may be wider (thicker) on the outflow side than on the inflow side of the reaction gas. If it does in this way, the area of a conductive layer can be increased toward the outflow side from the inflow side of a reactive gas. Therefore, in the fuel cell, a difference in current collection resistance occurs in the fuel cell. That is, the conductive layer is set so as to increase the current collecting resistance at a location where the fuel gas and oxidizing gas concentrations in the cell surface are high, such as on the gas inflow side. On the other hand, the conductive layer is set so as to reduce the current collecting resistance at a location where the fuel gas and oxidizing gas concentrations in the cell surface are low, such as the gas outflow side. As a result, a difference in power generation between the inflow side and the outflow side of the reaction gas is less likely to occur, and cell cracking and early deterioration of cell characteristics can be avoided.

  The widths of the connection parts in the conductive layer are the same on the inflow side and the outflow side of the reaction gas, and the number of connection parts existing between the contact pad parts of the adjacent current collector contact parts is larger than that on the inflow side. There may be more on the side. Even in this case, the area of the conductive layer can be increased from the reaction gas inflow side to the outflow side. Therefore, in the fuel cell, a difference in current collection resistance occurs in the fuel cell. That is, the conductive layer is set so as to increase the current collection resistance at a location where the concentration of the fuel gas and the oxidizing gas in the cell surface is high, such as the gas inflow side. On the other hand, the conductive layer is set so as to reduce the current collecting resistance at a location where the fuel gas and oxidizing gas concentrations in the cell surface are low, such as the gas outflow side. As a result, a difference in power generation between the inflow side and the outflow side of the reaction gas is less likely to occur, and cell cracking and early deterioration of cell characteristics can be avoided.

  In the conductive layer, the area ratio of the portion excluding the contact pad portion of the current collector contact portion is 1% or more and 10% or less with respect to the surface area of the electrode excluding the area of the current collector contact portion. Here, when the area ratio of the portion excluding the contact pad portion in the conductive layer is less than 1%, the width of the connection portion or the pad extension portion connecting the contact pad portions of the adjacent current collector contact portions is narrow. Therefore, the current collection resistance difference in the cell plane is reduced. For this reason, it is impossible to generate a sufficient current collection resistance difference to meet the tendency of the in-plane gas concentration difference, and it is not possible to suppress the power generation variation in the cell plane, which is a problem of the present application. In addition, when the area ratio of the conductive layer excluding the contact pad portion exceeds 10%, the area of the connection portion or the pad extension portion becomes too large, so that the gas permeability in the electrode is deteriorated and the cell characteristics are deteriorated. Resulting in. Therefore, in the fuel cell, by setting the area ratio of the conductive layer excluding the contact pad portion to 1% or more and 10% or less, current concentration (collection) due to non-uniform power generation is avoided while avoiding deterioration of cell characteristics. Increase in electrical resistance) can be avoided.

  The conductive layer is formed using a conductive material having a resistance value lower than that of the electrode forming material. Specifically, the conductive layer includes platinum (Pt), silver (Ag), palladium (Pd), lanthanum (La), strontium (Sr), manganese (Mn), cobalt (Co), iron (Fe), copper It is formed using a conductive material containing at least one of (Cu), nickel (Ni), gold (Au), iridium (Ir), ruthenium (Ru), and rhodium (Rh). When a conductive layer is formed using such a conductive material, charge transfer is facilitated through the conductive layer, and current collection efficiency can be increased.

  The conductive layer may include a perpendicular connection portion and a parallel connection portion with respect to the flow of the reaction gas. The plurality of current collector contact portions may have the same shape and area, and may be regularly set in a grid pattern vertically and horizontally on the surface of the electrode. If it does in this way, it can collect reliably with a current collector, ensuring the flow path of a reactive gas between the protrusion of an electrical power collector, and the electrode surface in a fuel cell.

  The fuel cell is used in a solid oxide fuel cell, and the electrode on which the conductive layer is formed may be a fuel electrode or an air electrode. In this case, since the transfer of electrons between each electrode and the current collector is efficiently performed through the conductive layer, the power generation efficiency can be sufficiently increased.

  A connection part is formed so as to connect between the contact pad parts of the adjacent current collector contact parts with respect to some of the plurality of current collector contact parts arranged in a scattered manner within the surface of the electrode. May be. When the conductive layer (the contact pad portion and the connection portion) is formed in this manner, even when a part of the current collector contact portion is separated from the protrusion of the current collector due to thermal deformation of the fuel cell during power generation, the separation is performed. Since the contact pad portion of the current collector contact portion and the contact pad portion of the current collector contact portion adjacent thereto are electrically connected by the connection portion, sufficient current collection capability can be ensured. . As a result, the fuel battery cell can efficiently generate power without voltage loss.

In the case where the electrolyte layer constituting the fuel cell is a solid oxide layer, examples of the forming material include ZrO ₂ ceramic and LaGaO ₃ ceramic.

The air electrode is in contact with an oxidant gas (reactive gas) serving as an oxidant, and functions as a positive electrode in the fuel cell. Here, examples of the material for forming the air electrode include a metal material, a metal oxide, and a metal composite oxide. Preferable examples of the metal material include Pt, Au, Ag, Pd, Ir, Ru, Rh, etc., and alloys thereof. Preferable examples of metal oxides include La, Sr, Ce, Co, Mn, Fe oxides (La ₂ O ₃ , SrO, CeO ₂ , Co ₂ O ₃ , MnO ₂ , FeO). . Preferable examples of metal composite oxides include, for example, composite oxides containing La, Pr, Sm, Sr, Ba, Co, Fe, and Mn (La _1-x Sr _x CoO ₃ -based composite oxide, La _{1 -x} Sr _x FeO _3-based composite _{oxide, La 1-x Sr x Co} 1-y Fe y O 3 composite _{oxide, La 1-x Sr x MnO} 3 composite _oxide, Pr _1-x Ba _x CoO ₃ type composite oxide, Sm _1-x Sr _x CoO ₃ type composite oxide) and the like.

  Examples of the oxidant gas include a mixed gas of oxygen and another gas. This mixed gas may contain an inert gas such as nitrogen or argon. The mixed gas is preferably safe and inexpensive air.

The fuel electrode is in contact with a fuel gas (reactive gas) serving as a reducing agent and functions as a negative electrode in the fuel cell. Here, examples of the material for forming the fuel electrode include ZrO ₂ ceramics stabilized by rare earth elements (Sc, Y, etc.), and CeO ₂ ceramics doped with rare earth elements (Sm, Gd, etc.). Among them, a metal ceramic material in which at least one ceramic material is mixed with at least one of metal materials such as Pt, Au, Ag, Pd, Ir, Ru, Rh, Ni, Fe and alloys of these metal materials. Mixtures (cermets) can be used.

  Examples of the fuel gas include hydrogen gas, hydrocarbon gas, and a mixed gas of hydrogen gas and hydrocarbon gas. When the hydrocarbon gas is selected as the fuel gas, the type of the hydrocarbon gas is not particularly limited, but is preferably natural gas, naphtha, coal gasification gas, or the like. It is obtained by mixing water vapor with fuel gas obtained by passing gas (hydrogen gas, hydrocarbon gas, mixed gas) in water and humidifying it, or gas (hydrogen gas, hydrocarbon gas, mixed gas). The fuel gas to be used may be selected. Further, only one type of fuel gas may be used, or a plurality of types of fuel gas may be used in combination. Further, the fuel gas may contain an inert gas such as nitrogen or argon. Moreover, what vaporized the liquid raw material can be used as fuel gas, or hydrogen gas produced by reforming a gas other than hydrogen gas can be used as fuel gas.

  Further, as another means (means 2) for solving the above-mentioned problem, the fuel cell according to means 1 and a plurality of projections for collecting current are provided, and the front end surfaces of the plurality of projections are A current collector disposed on the surface of the electrode so as to contact the current collector contact portion, and a plurality of the fuel cells and the current collector are stacked. There is a fuel cell stack.

  According to the invention described in Means 2, the fuel cell stack is configured by laminating a plurality of fuel cells and current collectors of Means 1. In this fuel cell stack, in each fuel cell, it becomes difficult for a difference in power generation between the inflow side and the outflow side of the reaction gas, and cell cracks and early deterioration of cell characteristics can be avoided. Therefore, it is possible to efficiently generate power in the fuel cell stack.

  Moreover, a solid oxide fuel cell (SOFC) is mentioned as a fuel cell comprised using said fuel cell stack. The fuel cell of the present invention includes a solid oxide electrochemical cell such as a solid oxide electrolytic cell (SOEC).

The schematic block diagram which shows the fuel cell of this Embodiment. The schematic sectional drawing which shows a fuel cell stack. The top view which shows arrangement | positioning of the processus | protrusion of a collector. The top view which shows a collector contact part and a conductive layer. The top view which shows the conductive layer of another embodiment which has a connection part from which a connection number differs. The top view which shows the conductive layer of another embodiment which has a connection part from which a connection number differs. The top view which shows the conductive layer of another embodiment which has a connection part from which width | variety differs, when a gas flow is a coflow. The top view which shows the conductive layer of another embodiment which has a connection part from which a connection number differs, when a gas flow is a coflow. The top view which shows the conductive layer of another embodiment which has a contact pad part and a pad expansion part. The top view which shows the conductive layer of another embodiment which has a contact pad part, a connection part, and a pad expansion part. The top view which shows the conductive layer of another embodiment which has a contact pad part and a connection part. The top view which shows the conductive layer of another embodiment which has a circular-shaped air electrode.

  Hereinafter, an embodiment in which the present invention is embodied in a fuel cell will be described in detail with reference to the drawings.

  The fuel cell 100 of the present embodiment is a solid oxide fuel cell (SOFC). As shown in FIG. 1, the fuel cell 100 includes a fuel cell stack 112 formed by stacking a plurality of fuel cells 111 as a minimum unit of power generation.

  The fuel cell stack 112 has, for example, a substantially rectangular parallelepiped shape with a length of 180 mm × width of 180 mm × height of 80 mm. In the present embodiment, the number of stacked fuel cells 111 constituting the fuel cell stack 112 is about 20. In the fuel cell stack 112, end plates 14 and 15 are arranged at both ends (upper and lower ends in FIG. 1) in the stacking direction of the fuel cells 111. Furthermore, a plurality of through-holes that penetrate the stack 112 in the thickness direction are formed in the peripheral portion of the cell stack 112. The fastening bolts 18 are inserted into the through holes, and nuts 19 are screwed to the lower end portions of the bolts 18 protruding from the lower surface of the cell stack 112. In this way, the plurality of fuel cells 111 are fixed by tightening the end plates 14 and 15 in the stacking direction of the fuel cells 111 using the fastening bolts 18 and the nuts 19. Further, the end plates 14 and 15 disposed at both ends of the cell stack 112 serve as output terminals for current output from the cell stack 112.

  As shown in FIG. 2, the fuel cell 111 constituting the cell stack 112 is configured as a flat plate member having an air electrode 21, a fuel electrode 22, and a solid electrolyte layer 23, and generates electric power by a power generation reaction. In addition to the fuel cell 111, the cell stack 112 is provided with a connector plate 24, a separator 25, an air electrode current collector 27, a fuel electrode current collector 28, and the like, and a plurality of these are stacked. ing.

  More specifically, the connector plates 24 are formed of a conductive material such as stainless steel, and a pair of connector plates 24 are disposed on both sides of the fuel cell 111 in the thickness direction. Each connector plate 24 ensures conduction between the fuel cells 111 in the thickness direction. The connector plate 24 disposed between the adjacent fuel cells 111 serves as an interconnector, and separates the adjacent fuel cells 111.

  The separator 25 is made of a conductive material such as stainless steel and has a substantially rectangular frame shape having a rectangular opening 29 at the center. The separator 25 functions as a partition plate between the fuel cells 111.

  The solid electrolyte layer 23 is formed in a rectangular plate shape by a ceramic material (oxide) such as yttria stabilized zirconia (YSZ). The solid electrolyte layer 23 is fixed to the lower surface of the separator 25 and is disposed so as to close the opening 29 of the separator 25. The solid electrolyte layer 23 functions as an oxygen ion conductive solid electrolyte body.

  An air electrode 21 in contact with the oxidant gas supplied to the cell stack 112 is attached to the upper surface of the solid electrolyte layer 23, and the fuel gas supplied to the cell stack 112 is also attached to the lower surface of the solid electrolyte layer 23. A fuel electrode 22 in contact therewith is affixed. That is, the air electrode 21 and the fuel electrode 22 are disposed on both sides of the solid electrolyte layer 23. The air electrode 21 is disposed in the opening 29 of the separator 25 so as not to contact the separator 25. In the fuel cell 111 of the present embodiment, the fuel chamber 31 is formed below the separator 25 and the air chamber 32 is formed above the separator 25.

In the fuel cell 111 of the present embodiment, the air electrode 21 is formed in a rectangular plate shape by LSCF (La _0.6 Sr _0.4 Co _0.2 Fe _0.8 O ₃ ) which is a metal complex oxide. Has been. The fuel electrode 22 is formed in a rectangular plate shape by a mixture of nickel and yttria-stabilized zirconia (Ni-YSZ). In the fuel cell 111, the air electrode 21 functions as a cathode layer, and the fuel electrode 22 functions as an anode layer.

  The air electrode 21 is electrically connected to the connector plate 24 by the air electrode side current collector 27, and the fuel electrode 22 is electrically connected to the connector plate 24 by the fuel electrode side current collector 28. The air electrode side current collector 27 is made of a dense metal plate such as a SUS430 ferrite alloy to which a small amount of La, Mn, Ti, Si, C, Ni, Al, Zr or the like is added. On the other hand, the fuel electrode side current collector 28 is made of, for example, a nickel porous body so that the fuel gas can pass therethrough.

  As shown in FIGS. 2 to 4, the air electrode side current collector 27 has a plurality of protrusions 35 for collecting current, and the tip surfaces of the protrusions 35 are on the surface of the air electrode 21. It arrange | positions adjacent to the fuel cell 111 so that the collector contact part 37 set in the shape of a dot may be contacted. In the present embodiment, the plurality of current collector contact portions 37 are, for example, quadrangular regions, have the same shape and area, and are regularly set in a grid pattern vertically and horizontally on the surface of the air electrode 21. . The plurality of protrusions 35 in the air electrode side current collector 27 are quadrangular protrusions having the same shape and size, and are regularly arranged in a lattice shape vertically and horizontally.

  As shown in FIG. 4, the fuel cell 111 of the present embodiment is provided with a conductive layer 138 on the surface of the air electrode 21. The conductive layer 138 is provided in each inner region of the current collector contact portion 37, and the contact pad portion 139 with which the protrusion 35 of the air electrode side current collector 27 abuts and the adjacent current collector contact portion 37 abuts. And a connection portion 140 formed so as to connect the pad portions 139. The air electrode 21 has a quadrangular shape in plan view. The conductive layer 138 is made of a silver-palladium alloy (alloy having a palladium content of 1 to 10 mol%), and has a thickness of, for example, about several tens of μm. Here, the inner region of the current collector contact portion 37 is a region where the quadrangular protrusions 35 of the air electrode side current collector 27 are in contact, and is a region at the center of the current collector contact portion 37, that is, a square. A region located inside the shape.

  Further, in the fuel cell 111, the contact pad portion 139 is provided in the inner region of the plurality of current collector contact portions 37 set in a scattered manner on the surface of the air electrode 21 so as to cover the entire region. The air electrode 21 and the air electrode side current collector 27 are joined via the contact pad portion 139 (see FIG. 2). In the fuel cell 111 of the present embodiment, the area of the conductive layer 138 excluding the contact pad portion 139 of the current collector contact portion 37 (connection portion 140 protruding from the inner region of the current collector contact portion 37). The ratio is about 5% with respect to the surface area of the air electrode 21 excluding the area of the current collector contact portion 37. In the present embodiment, the connecting portion 140 of the conductive layer 138 is a developed pattern extending from the inner region (contact pad portion 139) of the current collector contact portion 37 to the outer region, and adjacent current collector contacts. It is formed between the parts 37. That is, the connection part 140 is a part that functions as a conducting wire that connects the contact pad parts 139 of the current collector contact portions 37.

  In the fuel cell stack 112 of the present embodiment, a fuel supply path (not shown) for supplying fuel gas to the fuel chamber 31 of each fuel cell 111 and a fuel discharge path (for discharging fuel gas from the fuel chamber 31) ( (Not shown). The cell stack 112 is provided with an air supply path (not shown) for supplying air to the air chamber 32 of each fuel battery cell 111 and an air discharge path (not shown) for discharging air from the air chamber 32. ing. Each supply path and each discharge path are connected to an external pipe (not shown) via a joint portion (not shown) provided on the side surface of the fuel cell stack 112.

  In the present embodiment, the reaction gas (fuel gas and oxidant gas) is supplied from the end surface portion of the fuel cell 111 through the external piping and each supply path. Specifically, as shown in FIG. 4, a cross flow (orthogonal flow) system is adopted as the flow of the reaction gas (fuel gas F1 and oxidant gas A1). In the fuel cell 111, the oxidant gas A <b> 1 is supplied from the right side to the left side in FIG. 4 along the surface direction of the air electrode 21. On the other hand, the fuel gas F <b> 1 is supplied from the upper side to the lower side in FIG. 4 along the surface direction of the fuel electrode 22 on the back side of the air electrode 21. That is, in the present embodiment, the flow of the oxidant gas A1 and the flow of the fuel gas F1 are orthogonal.

  On the surface of the air electrode 21, the conductive layer 138 is formed unevenly as a whole so as to have a density in the planar direction of the electrode. More specifically, the conductive layer 138 has an area ratio per unit area in the surface of the air electrode 21 from the inflow side to the outflow side of the reaction gases F1 and A1 supplied along the plane direction of the air electrode 21. It is formed from coarse to dense. Specifically, in the present embodiment, the individual widths of the connection portions 140 existing between the contact pad portions 139 of the adjacent current collector contact portions 37 are the inflow sides (upper and right sides) of the reaction gases F1 and A1. ) Is wider than the outflow side (lower side and left side). That is, the connecting portion 140 located at the upper right is formed to be the narrowest, while the connecting portion 140 located at the lower left is formed to be the widest. As a result, the individual areas of the connection part 140 are larger on the outflow side than on the inflow side of the reaction gases F1 and A1.

  During power generation of the fuel cell 100, a power generation reaction occurs between the air electrode 21 and the air electrode side current collector 27 via the conductive layer 138 (the contact pad portion 139 and the connection portion 140) formed as described above. Accompanied by electronic transfer.

  Next, a method for manufacturing the fuel cell stack 112 in the present embodiment will be described.

  First, for example, a plate material made of SUS430 is punched to manufacture the connector plate 24 and the separator 25. Further, the material of the solid electrolyte layer 23 is printed on the green sheet of the fuel electrode 22, and the material of the air electrode 21 is printed thereon, followed by firing. By this firing, a flat plate fuel cell 111 having the air electrode 21, the fuel electrode 22, and the solid electrolyte layer 23 is manufactured.

  Thereafter, the fuel cell 111 and the separator 25 are fixed by brazing. Further, the air electrode side current collector 27 and the fuel electrode side current collector 28 are fixed to the adjacent upper connector plate 24 and lower connector plate 24 by brazing, respectively.

  Moreover, an Ag-Pd conductive paste is produced by mixing three rolls of Ag-Pd powder (Pd: 1 mol%), ethyl cellulose, and an organic solvent. Next, the conductive paste is screen-printed on the surface of the air electrode 21 and then dried. Here, the pattern of the contact pad portion 139 corresponding to each current collector contact portion 37 and the pattern of the connection portion 140 connecting the current collector contact portions 37 are formed by a conductive paste.

  Then, the above-described connector plate 24, the fuel cell 111 brazed with the separator 25, the air electrode side current collector 27, the fuel electrode side current collector 28 and the like are assembled together, and those members including the fuel cell 111 are assembled. The fuel cell stack 112 is configured by stacking a plurality of layers. At this time, in the fuel cell stack 112, the fastening bolt 18 is fitted into the through hole, and the nut 19 is screwed to the tip thereof. As a result, the fuel cell stack 112 is assembled by integrating the fuel cells 111 while being pressed in the stacking direction.

  The conductive paste described above becomes the conductive layer 138 (silver palladium alloy) by removing ethyl cellulose and the like at the operating temperature of the fuel cell 100 (for example, 700 ° C.). Further, at the operating temperature of the fuel cell 100, the silver palladium alloy of the conductive layer 138 is softened, and the air electrode 21 and the air electrode side current collector 27 are in close contact with each other. When the operation is stopped, the contact pad portion 139 of the current collector contact portion 37 is joined and integrated with the air electrode 21 and the air electrode side current collector 27.

  Next, the operation of the fuel cell 111 in the fuel cell 100 of the present embodiment will be described.

  In the fuel cell 100, for example, while the fuel cell 100 is heated to the operating temperature, the fuel gas F1 is supplied from the fuel supply path to the fuel chamber 31, and the oxidant gas A1 is supplied from the air supply path to the air chamber 32. To do. In the present embodiment, in each fuel cell 111 of the cell stack 112, the oxidant along the plane direction of the air electrode 21 so that the flow of the fuel gas F1 and the oxidant gas A1 becomes a cross flow (cross flow). The gas A1 is supplied and the fuel gas F1 is supplied along the planar direction of the fuel electrode 22. At this time, hydrogen in the fuel gas F1 and oxygen in the oxidant gas A1 react (power generation reaction) through the solid electrolyte layer 23, and direct current power using the air electrode 21 as a positive electrode and the fuel electrode 22 as a negative electrode is generated. Occur. In the present embodiment, the conductive layer 138 (connection portion 140) formed on the surface of the air electrode 21 extends from the inflow side to the outflow side of the reaction gases F1 and A1 supplied along the planar direction of the electrode. It is formed so as to become coarse to dense. In this case, on the inflow side where the concentrations of the reaction gases F1 and A1 are high and the power generation reaction amount tends to increase, the power generation amount is suppressed because the area of the conductive layer 138 (connection portion 140) is small. On the other hand, on the outflow side where the concentrations of the reaction gases F1, A1 are low and the power generation reaction amount tends to decrease, the amount of power generation increases because the area of the conductive layer 138 (connection portion 140) is large. As a result, in the electrode planes of the air electrode 21 and the fuel electrode 22, electric power is efficiently generated without causing current concentration (increase in current collection resistance) between the inflow side and the outflow side of the reaction gases F1, A1.

  In the cell stack 112 of the present embodiment, a plurality of fuel cells 111 are stacked and connected in series. For this reason, in the fuel cell 100, DC power is generated from the upper end plate 14 (positive electrode) electrically connected to the air electrode 21 and the lower end plate 15 (negative electrode) electrically connected to the fuel electrode 22. Is output.

  Therefore, according to the present embodiment, the following effects can be obtained.

  (1) In the fuel cell 111 of the present embodiment, the conductive layer 138 is provided on the surface of the air electrode 21, and the connection part 140 constituting the conductive layer 138 is supplied along the planar direction. It is formed so as to increase from coarse to dense from the inflow side to the outflow side of the reaction gases F1, A1. In the fuel cell 100, power generation occurs when electrons are transferred from the air electrode side current collector 27 to the air electrode 21, and thus, by forming the conductive layer 138 having such a density, the fuel cell unit 111 includes the conductive layer 138. A difference in current collection resistance occurs. That is, the conductive layer 138 (connection portion 140) is set so as to increase the current collection resistance at a location where the fuel gas and oxidizing gas concentrations in the cell surface are high, such as the gas inflow side. On the other hand, the conductive layer 138 (connection portion 140) is set so as to reduce the current collection resistance at a location where the fuel gas and oxidizing gas concentrations in the cell surface are low, such as on the gas outflow side. As a result, in the plane of the fuel cell 111, the difference in power generation between the inflow side and the outflow side of the reaction gas F1, A1 is less likely to occur, and the variation in the power generation amount in the plane of the fuel cell 111 is eliminated. The difference in temperature distribution at the time becomes smaller. Therefore, cell cracks and early deterioration of cell characteristics as in the prior art can be avoided, and power generation can be performed efficiently.

  (2) In the fuel cell 111 of the present embodiment, the protrusions 35 of the air electrode side current collector 27 are arranged in a scattered manner with a predetermined interval, and the reaction gases F1, A1 are provided as in the prior art. It is not necessary to change the shape of the current collector 27 according to the flow of the current. For this reason, in the fuel cell 111, the flow rate of the oxidant gas A1 supplied to the air electrode 21 can be sufficiently ensured. Furthermore, in the fuel cell 111 of the present embodiment, the processing cost associated with the shape change of the air electrode side current collector 27 is not necessary, and therefore the manufacturing cost of the fuel cell 111 can be suppressed.

  (3) In the fuel battery cell 111 of the present embodiment, the connection portion 140 has an individual width wider on the outflow side than the inflow side of the reaction gas F1, A1, and the inflow side of the reaction gas F1, A1. The area on the outflow side is larger than that. When the connection part 140 is formed in this way, a difference in current collection resistance occurs in the plane of the fuel cell 111. Since the increase / decrease in the gas concentration in the cell surface and the increase / decrease in the current collecting resistance are opposite, a difference in power generation hardly occurs between the inflow side and the outflow side of the reaction gases F1, A1. As a result, variations in power generation amount are eliminated, and cell cracks and early deterioration of cell characteristics can be reliably avoided.

  (4) In the fuel cell 111 according to the present embodiment, the area ratio of the connection part 140 of the conductive layer 138 (the part excluding the contact pad part 139 of the current collector contact part 37) is the same as that of the current collector contact part 37. It is about 5% with respect to the surface area of the air electrode 21 excluding the area. Here, when the area ratio of the connection portion 140 is less than 1%, the width of the connection portion 140 that connects the contact pad portions 139 of the adjacent current collector contact portions 37 becomes narrow, so that the collector in the cell plane is reduced. The electric resistance difference is reduced. For this reason, it is impossible to produce a sufficient current collection resistance difference that is commensurate with the tendency of the in-plane gas concentration difference, and it is not possible to suppress power generation variations in the cell plane. Moreover, when the area ratio of the connection part 140 exceeds 10%, the gas permeability in the air electrode 21 deteriorates and the cell characteristic falls because the area of the connection part 140 becomes too large. Therefore, as in the fuel battery cell 111 of the present embodiment, by setting the area ratio of the connection part 140 to 5%, current concentration due to nonuniform power generation (collection resistance) is avoided while avoiding deterioration of cell characteristics. Rise) can be avoided.

  (5) In the fuel battery cell 111 of the present embodiment, the inner regions of the plurality of current collector contact sites 37 set in the form of dots on the surface of the air electrode 21 are covered with the entire region. A contact pad portion 139 is formed, and the air electrode 21 and the air electrode side current collector 27 are joined via the contact pad portion 139. If comprised in this way, the contact resistance between each processus | protrusion 35 of the air electrode side collector 27 and the air electrode 21 can be restrained low, and current collection efficiency can fully be improved.

  (6) In the fuel battery cell 111 of the present embodiment, the plurality of current collector contact portions 37 have the same shape and area, and are regularly set in a grid pattern vertically and horizontally on the surface of the air electrode 21. . In this way, in the fuel cell 111, the air electrode side current collector 27 secures a flow path of the oxidant gas A1 between the protrusion 35 of the air electrode side current collector 27 and the surface of the air electrode 21. The current can be reliably collected.

  (7) In the fuel cell 111 of the present embodiment, the conductive layer 138 is formed using a conductive material (specifically, a silver-palladium alloy) having a lower resistance value than the material for forming the air electrode 21. When the conductive layer 138 is formed using such a conductive material, charge transfer is facilitated through the conductive layer 138, and the current collection efficiency of the fuel cell 111 can be further increased.

  In addition, you may change embodiment of this invention as follows.

  In the above embodiment, each connecting portion 140 is formed such that the individual width is wider on the outflow side than the inflow side of the reaction gases F1 and A1, but this is not restrictive. Like the conductive layer 143 shown in FIG. 5, the individual widths of the connection portions 145 are the same on the inflow side and the outflow side of the reaction gases F <b> 1 and A <b> 1, and the contact pad portions 144 of the adjacent current collector contact portions 37 are present. You may form so that the current collector contact site | part 37 in the outflow side may increase more than the current collector contact site | part 37 in the inflow side. Even in this case, the connection portion 145 of the conductive layer 143 is such that the area ratio per unit area in the surface of the air electrode 21 becomes coarser and denser from the inflow side to the outflow side of the reaction gases F1, A1. It is formed. For this reason, in the fuel cell 111, a difference in power generation amount hardly occurs between the inflow side and the outflow side of the reaction gases F1 and A1. Therefore, cell cracks and early deterioration of cell characteristics in the fuel cell 100 can be avoided, and power generation can be performed efficiently.

  In the above-described embodiment, the connection portions 140 and 145 of the conductive layers 138 and 143 include the connection portions 140 and 145 parallel to the connection portions 140 and 145 perpendicular to the flow of the reaction gas F1 and A1, respectively. However, the present invention is not limited to this. Like the conductive layer 146 (the contact pad portion 147 and the connection portions 148 and 149) shown in FIG. 6, the connection portion 148 parallel to the connection portion 148 perpendicular to the flow direction of the reaction gases F1 and A1 In addition, an inclined connection portion 149 may be formed. Further, in the above embodiment, the flow of the reaction gas (fuel gas F1 and oxidant gas A1) is embodied as a cross flow (cross flow), but the flow of co-flow (parallel flow), counter flow (counter flow) ). 7 and 8 show specific examples when the fuel gas F1 and the oxidant gas A1 are supplied to each electrode by coflow. 7 and 8, the oxidant gas A1 flows from the upper side to the lower side in the drawing along the plane direction of the air electrode 21. 7 and 8, the fuel gas F1 flows from the upper side to the lower side in the drawing along the planar direction of the fuel electrode 22 (not shown) on the back side of the air electrode 21. In the conductive layer 151 shown in FIG. 7, on the surface of the air electrode 21, the connection part 153 existing between the contact pad parts 152 of the current collector contact part 37 is the inflow side of the reaction gas F <b> 1, A <b> 1 (upper side in FIG. 7). ) Is wider than the pattern on the outflow side (lower side in FIG. 7). Further, in the conductive layer 155 shown in FIG. 8, the number of connection portions 157 and 158 existing between the contact pad portions 156 of the current collector contact portion 37 on the surface of the air electrode 21 is the inflow side of the reaction gases F1 and A1. More patterns are formed on the outflow side (lower side in FIG. 8) than on the pattern (upper side in FIG. 8). Even when the conductive layers 151 and 155 are formed as shown in FIGS. 7 and 8, it is difficult for a difference in power generation to occur between the inflow side and the outflow side of the reaction gases F1 and A1. Therefore, cell cracks and early deterioration of cell characteristics in the fuel cell 100 can be avoided, and power generation can be performed efficiently.

  In the above embodiment, the conductive layers 138, 143, 146, 151, 155 are the contact pad portions 139, 144, 147, 152, 156 formed in the inner regions of the current collector contact portions 37, and The contact portions 139, 144, 147, 152, and 156 have connection portions 140, 145, 148, 149, 153, 157, and 158 formed to connect the contact pads 139, 144, 147, 152, and 156. However, the present invention is not limited to this. Absent. As shown in FIG. 9, a rectangular island-shaped conductive layer 161 that does not connect the current collector contact portions 37 may be formed. In FIG. 9, the conductive layer 161 formed on the surface of the air electrode 21 includes a contact pad portion 162 provided in an inner region of the current collector contact portion 37, and a current collector contact portion from the contact pad portion 162. 37 and a pad extension 163 provided so as to protrude from the outside. The area (width) of the pad extension 163 that protrudes outward from the current collector contact portion 37 is increased toward the outflow side of the reaction gas F1, A1 inflow side. That is, the area of each of the rectangular island-shaped conductive layers 161 (the contact pad portion 162 and the pad extension portion 163) increases toward the outflow side. In FIG. 9, each conductive layer 161 is also formed in a square shape in accordance with the shape of the current collector contact portion 37, but the present invention is not limited to this, and the pad extension portion is formed so as to be a circular conductive layer. May be formed. That is, in the fuel cell 111, the conductive layer 161 is formed so that the area of the pad expansion part 163 connected to the current collector contact part 37 on the outflow side is larger than the pad expansion part 163 connected to the current collector contact part 37 on the inflow side. As long as it forms, the shape of the pad expansion part 163 may be changed suitably. Even if the fuel cell 111 is configured in this manner, a difference in current collection resistance occurs in the fuel cell 111. That is, since the increase / decrease in the gas concentration in the cell plane is opposite to the increase / decrease in the current collecting resistance, a difference in power generation hardly occurs between the inflow side and the outflow side of the reaction gases F1, A1. Therefore, cell cracks and early deterioration of cell characteristics in the fuel cell 100 can be avoided, and power generation can be performed efficiently.

  Further, as in the conductive layer 165 shown in FIG. 10, some of the plurality of current collector contact portions 37 arranged in a scattered manner within the surface of the air electrode 21 (for example, current collector contact at the corner portion). For the portion 37 only, the connection portion 167 may be formed so as to connect the contact pad portions 166 of the adjacent current collector contact portions 37. The connection part 167 connecting the contact pad parts 166 of the current collector contact part 37 is a part where warpage in a direction away from the air electrode side current collector 27 occurs due to thermal deformation of the fuel cell 111 during power generation. Formed. Thus, even when a part of the current collector contact portion 37 is separated from the protrusion 35 of the air electrode side current collector 27 due to thermal deformation of the fuel battery cell 111, the current collector contact portion 37 adjacent to the corner portion. Through the contact pad portion 166 and the connecting portion 167 of the current collector contact portion 37 in the corner portion (which is separated from the air electrode side current collector 27 and remains on the electrode surface) (without increasing the current collecting resistance) Can collect current. Therefore, deterioration of the power generation efficiency in the fuel cell 111 can be avoided.

  Further, in the conductive layer 165 of FIG. 10, a pad expansion portion 168 is provided so as to protrude from the contact pad portion 166 to the outside of the current collector contact portion 37. In the conductive layer 165, the area of the pad expansion portion 168 that protrudes outward from the current collector contact portion 37 is made larger toward the outflow side than the inflow side of the reaction gases F1 and A1. Even if the conductive layer 165 is formed in this way, the increase / decrease in the gas concentration in the cell surface and the increase / decrease in the current collecting resistance are reversed, so there is a difference in the amount of power generation between the inflow side and the outflow side of the reaction gases F1, A1. Is less likely to occur. Therefore, cell cracks and early deterioration of cell characteristics in the fuel cell 100 can be avoided, and power generation can be performed efficiently.

  In the embodiment described above, in the air electrode 21, the contact pad portions 139, 144, 147, 152, 156, 162, 166 are formed in the inner region of each current collector contact portion 37 so as to cover the entire region. However, the present invention is not limited to this. For example, as shown in FIG. 11, on the surface of the air electrode 21, a rectangular shape is formed so as to connect the inner region of each current collector contact portion 37 and the inner region of the current collector contact portion 37 adjacent thereto. The conductive layer 171 (the contact pad portion 172 and the coupling portion 173) may be formed. Each conductive layer 171 is formed so as to overlap only a part of the inner region of each current collector contact portion 37, and the portion overlapping this inner region becomes the contact pad portion 172. In addition, a portion that connects between the contact pad portions 172 of the adjacent current collector contact portions 37 becomes a coupling portion 173. These rectangular conductive layers 171 (joining portions 173) are formed such that the individual thicknesses are larger on the outflow side (lower side and left side) than the inflow side (upper side and right side) of the reaction gases F1, A1. Has been. That is, the conductive layer 171 (coupling portion 173) located at the upper right is formed to be the thinnest, while the conductive layer 171 (coupling portion 173) located at the lower left is formed to be the thickest. As a result, the individual areas of the conductive layer 171 (coupling portion 173) are larger on the outflow side than on the inflow side of the reaction gases F1 and A1. Even if the fuel cell 111 is configured in this manner, a difference in current collection resistance occurs in the fuel cell 111. Since the increase / decrease in the gas concentration in the cell surface and the increase / decrease in the current collecting resistance are opposite, a difference in power generation hardly occurs between the inflow side and the outflow side of the reaction gases F1, A1. Therefore, cell cracks and early deterioration of cell characteristics in the fuel cell 100 can be avoided, and power generation can be performed efficiently.

  In the above embodiment, the conductive layers 138, 143, 146, 151, 155, 161, 165, and 171 are formed on the square air electrode 21 (electrode), but the electrode shape is limited to a square shape. However, the conductive layer may be formed on the air electrode 21 having a polygonal shape other than a circular shape or a square shape. FIG. 12 shows a specific example in which the conductive layer 176 (the contact pad portion 178 and the coupling portions 179, 180, and 181) is formed on the electrode surface of the circular air electrode 175. Also in the air electrode 175 of FIG. 12, a plurality of current collector contact portions 177 with which the air electrode side current collector is in contact are provided in a dotted pattern. In this circular air electrode 175, an oxidant gas is supplied to the electrode central portion 175a, and the gas after the battery reaction is discharged from the electrode outer edge portion 175b side. In the air electrode 175, a plurality of current collector contact portions 177 are respectively set at positions on two circumferences having different diameters. In the air electrode 175, coupling portions 179 and 180 are provided so as to connect the contact pad portions 178 of the adjacent current collector contact portions 177 with respect to the current collector contact portions 177 located on the same circumference. ing. Furthermore, in the air electrode 175, the current collector contact portion 177 at the four locations of the right end, the left end, the upper end, and the lower end on the electrode outer edge portion 175b side, and the current collector adjacent to the current collector contact portion 177 on the inner side A connecting portion 181 is formed so as to connect the contact portions 177 with each other. And the coupling | bonding which exists between the contact pad parts 178 of the collector contact part 177 of the outer peripheral part side rather than the coupling | bond part 179 which exists between the contact pad parts 178 of the collector contact part 177 of the electrode center part 175a side. The conductive layer 176 is formed so that the area of the portion 180 is larger (thicker width). Even when the conductive layer 176 is formed in this way, a difference in power generation amount hardly occurs between the inflow side and the outflow side of the reaction gases F1 and A1. Therefore, cell cracks and early deterioration of cell characteristics in the fuel cell 100 can be avoided, and power generation can be performed efficiently.

  In the above embodiment, the conductive layers 138, 143, 146, 151, 155, 161, 165, 171 and 176 are formed on the surfaces of the air electrodes 21 and 175. A layer may be formed. Even in this case, the fuel electrode-side current collector 28 has a plurality of protrusions, and the fuel electrode 22 has a current collector contact portion where the protrusions of the fuel electrode-side current collector 28 can come into contact with each other. The Then, a conductive layer is formed on the surface of the fuel electrode 22 so as to be dense according to the flow of the reaction gases F1 and A1. Even if the fuel battery cell is configured in this way, a difference in power generation amount hardly occurs between the inflow side and the outflow side of the reaction gases F1 and A1. As a result, cell cracks in the fuel cell and early deterioration of cell characteristics can be avoided.

  In the above embodiment, the shape of the current collector contact portions 37 and 177 (each projection 35 of the air electrode side current collector 27) is a regular square shape, but the shape is changed to a rectangular shape, a circular shape, an elliptical shape, or the like. May be.

  In the above embodiment, the conductive layers 138, 143, 146, 151, 155, 161, 165, 171, 176 are formed by firing the conductive paste according to the operating temperature of the solid oxide fuel cell 100. However, the fuel cell stack 112 may be manufactured by separately performing a firing process for forming the conductive layers 138, 143, 146, 151, 155, 161, 165, 171, 176. Further, the conductive layers 138, 143, 146, 151, 155, 161, 165, 171, 176 are formed simultaneously with the firing process of the air electrodes 21, 175, the fuel electrode 22, and the solid electrolyte layer 23 in the fuel battery cell 111. Good.

  Next, in addition to the technical ideas described in the claims, the technical ideas grasped by the embodiments described above are listed below.

  (1) In the means 1, the individual widths of the connection portions are the same on the inflow side and the outflow side of the reaction gas, and the widths of the connection portions existing between the contact pad portions of the current collector contact portions adjacent to each other. The number of the fuel cells is greater on the outflow side than on the inflow side.

  (2) The fuel cell according to means 1, wherein the conductive layer is formed using a conductive material having a resistance value lower than that of the material for forming the electrode.

  (3) In means 1, the conductive layer comprises platinum (Pt), silver (Ag), palladium (Pd), lanthanum (La), strontium (Sr), manganese (Mn), cobalt (Co), iron (Fe ), Copper (Cu), nickel (Ni), gold (Au), iridium (Ir), ruthenium (Ru), rhodium (Rh), and a conductive material. Fuel cell.

  (4) In the fuel cell according to (1), the conductive layer includes the connection part perpendicular to the flow of the reaction gas and the connection part parallel to the connection part.

  (5) The fuel cell according to (1), wherein the plurality of current collector contact portions have the same shape and area, and are regularly set in a grid pattern vertically and horizontally on the surface of the electrode. .

  (6) The fuel cell according to means 1, wherein the electrode is used for a solid oxide fuel cell, and the electrode on which the conductive layer is formed is the air electrode.

  (7) In the means 1, with respect to a part of the plurality of current collector contact portions arranged in a scattered manner in the surface of the electrode, the contact pad portion of the adjacent current collector contact portion The said connection part is formed so that it may connect, The fuel cell characterized by the above-mentioned.

DESCRIPTION OF SYMBOLS 21,175 ... Air electrode 22 ... Fuel electrode 23 ... Solid electrolyte layer 27 ... Air electrode side current collector 35 ... Protrusion 37, 177 ... Current collector contact part 100 ... Fuel cell 111 ... Fuel cell 112 ... Fuel cell stack 138, 143, 146, 151, 155, 161, 165, 171, 176 ... Conductive layer 139, 144, 147, 152, 156, 162, 166, 172, 178 ... Contact pad 140, 145 , 148, 149, 153, 157, 158, 167, 173, 179 to 181 ... connection part 163, 168 ... pad extension part A1 ... oxidant gas as reaction gas F1 ... fuel gas as reaction gas

Claims (6)

Adjacent to a current collector having a plurality of protrusions for current collection, and configured as a flat plate member having a fuel electrode, an air electrode and an electrolyte layer, and at least one of the fuel electrode and the air electrode On the surface of the electrode, a fuel battery cell in which a current collector contact portion capable of contacting a plurality of protrusions of the current collector is set in a scattered shape,
Comprising a conductive layer provided on the surface of the electrode;
The conductive layer is provided in an inner region of each of the plurality of current collector contact portions, has a contact pad portion with which a protrusion of the current collector contacts, and the contact between the adjacent current collector contact portions It has at least one of a connection part provided so as to connect between pad parts and a pad extension part provided so as to protrude from the contact pad part to the outside of the current collector contact part,
At least one of the said connection part and the said pad expansion part is formed so that it may have density, The fuel cell characterized by the above-mentioned.   At least one of the connection part and the pad extension part has an area ratio per unit area in the surface of the electrode from the inflow side to the outflow side of the reaction gas supplied along the planar direction of the electrode. The fuel cell according to claim 1, wherein the fuel cell is formed to be coarse to dense.   3. The fuel cell according to claim 2, wherein an area of at least one of the connection part and the pad extension part is larger on an outflow side than on an inflow side of the reaction gas.   3. The fuel cell according to claim 2, wherein an individual width of at least one of the connection portion and the pad extension portion is wider on an outflow side than on an inflow side of the reaction gas.   In the conductive layer, an area ratio of a portion of the current collector contact portion excluding the contact pad portion is 1% or more and 10% or less with respect to a surface area of the electrode excluding an area of the current collector contact portion. The fuel cell according to claim 1, wherein the fuel cell is provided. The fuel battery cell according to any one of claims 1 to 5,
A plurality of protrusions for current collection, and a current collector disposed such that tip surfaces of the plurality of protrusions are in contact with the current collector contact portion set on the surface of the electrode, A fuel cell stack, wherein a plurality of the fuel cells and the current collector are laminated.

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