JP2017188342A - Fuel battery single cell and fuel battery stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a fuel battery single cell in which the power generation efficiency is increased by reducing an electric resistance in a fuel battery and increasing the efficiency of air supply to a cathode electrode; and a fuel battery stack with the fuel battery single cell.SOLUTION: A fuel battery single cell of the invention comprises: a fuel battery unit arranged by stacking an anode electrode, an electrolyte layer and a cathode electrode in turn; a contact material layer and a collecting sub-layer; and a current collector joined to the collecting sub-layer, and defining and forming an air flow path. On a cathode electrode side of the fuel battery unit, the contact material layer, the collecting sub-layer and the current collector are stacked in turn. The collecting sub-layer has a gas circulation hole running through itself in a stacking direction of the fuel battery unit, and a conductive part. The contact material layer is a porous body formed between the conductive part of the collecting sub-layer and the cathode electrode.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a fuel cell unit cell and a fuel cell stack in which a plurality of fuel cell unit cells are stacked. More specifically, the present invention relates to reducing the electrical resistance in the fuel cell and improving the efficiency of supplying air to the cathode electrode. The present invention relates to a fuel cell single cell with improved power generation efficiency and a fuel cell stack in which a plurality of the fuel cell single cells are stacked.

  In recent years, fuel cells have attracted attention as a clean energy source that has high power generation efficiency, generates almost no harmful exhaust gas, and is friendly to the global environment.

  Among various types of fuel cells, a solid oxide fuel cell (hereinafter, sometimes simply referred to as “SOFC”) transmits gas through a solid acid electrolyte layer and a cathode electrode (air electrode) that transmits gas. A fuel cell unit including an anode electrode (fuel electrode) and a current collector.

  In the fuel cell, the solid oxide electrolyte layer is used as a partition, and a fuel gas such as hydrogen or hydrocarbon is supplied to the fuel electrode, and air containing oxygen is supplied to the other air electrode.

  The current collector is joined to the fuel cell unit and collects the electric charge of the fuel cell unit, and forms a fuel gas flow path or an air flow path.

  Since the fuel cell unit is composed of a hard member, it is difficult to join the entire surface of the air electrode or the rib of the current collector if there is distortion. If they are not sufficiently bonded, the contact resistance increases and the power generation performance decreases.

Japanese Patent Application Laid-Open No. 2014-38732 of Patent Document 1 discloses a method in which a slurry containing a sintering accelerator such as boron oxide is applied to the entire surface of a cathode electrode, and a current collector is oversintered on the applied slurry. Adhesion between an electrode and a current collector is disclosed.
And it is disclosed that according to the adhesive layer formed by sintering the slurry, a decrease in power generation performance due to poor adhesion between the cathode electrode and the current collector can be suppressed.

JP 2014-38732 A

  However, the SOFC cathode electrode and the slurry are made of a metal oxide, and the metal oxide has a higher electrical resistance than a metal. Therefore, when the electric charge moves to the current collector, the power generation efficiency decreases as the distance for moving the cathode electrode or the adhesive layer becomes longer.

  In addition, the adhesive layer of Patent Document 1 covers the entire surface of the cathode electrode. In addition, air must circulate from the surroundings through the adhesive layer to the portion where the current collector of the cathode electrode is joined. In addition, since the efficiency of supplying air to the joint portion is reduced, it is not possible to perform power generation using the cathode electrode sufficiently.

  The present invention has been made in view of such problems of the prior art, and the object of the present invention is to reduce the electrical resistance, increase the efficiency of supplying air to the cathode electrode, and improve the power generation efficiency. It is to provide a single fuel cell.

  Another object of the present invention is to provide a fuel cell stack having high power generation efficiency using the fuel cell single cell.

  As a result of intensive studies to achieve the above object, the present inventor has provided a current collecting auxiliary layer for forming a conductive path between the cathode electrode and the current collector, and the cathode electrode and the current collecting auxiliary layer are provided with the current collecting auxiliary layer. It has been found that bonding with a porous contact material layer formed along the conductive path of the current collecting auxiliary layer can achieve both reduction in electrical resistance and improvement in air supply efficiency, and has completed the present invention.

That is, the fuel cell single cell of the present invention includes a fuel cell unit in which an anode electrode, an electrolyte layer, and a cathode electrode are sequentially laminated, a contact material layer, a current collecting auxiliary layer, and an air flow path bonded to the current collecting auxiliary layer. And a current collector for partitioning.
A contact material layer, a current collecting auxiliary layer, and a current collector are sequentially laminated on the cathode electrode side of the fuel cell unit, and the current collecting auxiliary layer penetrates in the laminating direction of the fuel cell unit. It has a circulation hole and a conductive part, and the contact material layer is a porous layer formed between the conductive part of the current collection auxiliary layer and the cathode electrode.

  The fuel cell stack according to the present invention is characterized in that a plurality of the fuel cell single cells are stacked.

  According to the present invention, since the current collecting auxiliary layer and the cathode electrode are joined by the porous contact material layer provided between the conductive portion of the current collecting auxiliary layer and the cathode electrode, a conductive path is formed. Thus, the electric resistance is reduced, the efficiency of supplying air to the cathode electrode is improved, and a single fuel cell and a fuel cell stack with high power generation efficiency can be provided.

It is a top view of the decomposition | disassembly state explaining the structure of a fuel cell single cell. It is principal part sectional drawing which shows an example of a fuel cell unit. It is principal part sectional drawing of an example of the fuel cell stack of this invention. It is principal part sectional drawing of another example of the fuel cell stack of this invention. It is the schematic explaining the flow of the air of the fuel cell single cell of this invention. It is the schematic explaining the flow of the air when not providing a contact material layer. It is a figure explaining the thickness and width of a contact material layer, and the line width of a current collection auxiliary layer. It is a figure which shows an example of an expanded metal. It is a figure which shows an example of a punching metal. It is a figure which shows an example of a metal mesh. It is a figure which shows an example of a cantilever spring. It is a graph of the cell voltage-current density of an Example and a comparative example.

The fuel cell single cell C of the present invention will be described in detail. An example of the fuel cell single cell of the present invention is shown in FIG.
The single fuel cell C includes a fuel cell unit 1, a contact material layer 2, a current collection auxiliary layer 3, and a current collector 4. As shown in FIG. 2, the fuel cell unit 1 includes an anode electrode 11, an electrolyte layer 12, and a cathode electrode 13 stacked in order, and is supported by a porous metal support 14 from the anode electrode side. is there.

  Hereinafter, a metal-supported cell (MSC) fuel cell unit in which an anode electrode, an electrolyte layer, and a cathode electrode are supported by a porous metal support 14 will be described as an example. The cell is composed of an electrolyte-supported cell (ESC) with a thick electrolyte, an anode-supported cell (ASC) with a thick anode, and a cathode-supported cell (CSC) with a thick cathode. Any of these may be used.

FIG. 1 is an exploded view illustrating the configuration of a single fuel cell.
The fuel cell unit 1 is formed by laminating the porous metal support 14, the anode electrode 11, the electrolyte layer 12, and the cathode electrode 13 in this order at the position indicated by the dotted line in FIG. 1. A frame 5 is provided on the outer edge of the porous metal support 14.

  Further, a contact material layer 2, a current collecting auxiliary layer 3, and a current collector 4 are sequentially laminated on the cathode electrode side of the fuel cell unit 1, and the current collector 4 further includes a porous cell of an adjacent fuel cell single cell. It has a structure joined to the porous metal support 14.

  The frame 5 and the current collector 4 are substantially rectangular shapes having substantially the same vertical and horizontal dimensions, and the fuel cell unit 1 and the frame and the current collector are overlapped and joined to form a fuel cell single cell C. .

The current collector 4 has a corrugated cross section in the short side direction at a central portion corresponding to the fuel cell unit 1. This wave shape is continuous in the long side direction as shown in FIG.
Thereby, the corrugated convex portion of the current collector 4, that is, the rib portion is bonded to the current collecting auxiliary layer 3 or the porous metal support 14 of the adjacent fuel cell single cell, and gas is provided to each concave portion in the corrugated shape A flow path is formed.

  Further, the fuel cell single cell C includes manifold portions H1 to H4 that communicate the frame and the current collector in the stacking direction. Then, air containing oxygen is supplied to the cathode electrode 13 on the front surface side of the fuel cell unit 1 shown in FIG. 1, and fuel gas is supplied to the anode electrode 11 on the back surface side.

  In the state where a plurality of the fuel cell single cells C are stacked, a seal 6 is provided between the fuel cell single cells, and the seal 6 hermetically separates the air and fuel gas flow areas between the individual layers. .

  Here, each member which comprises the said fuel cell single cell is demonstrated.

<Fuel cell unit>
The fuel cell unit 1 includes an anode electrode 11, an electrolyte layer 12, a cathode electrode 13, and a porous metal support 14 that are stacked in order, and generates power by an electrochemical reaction.

(Anode electrode)
As the anode electrode 11, a metal catalyst made of a metal and / or alloy having hydrogen oxidation activity and stable in a reducing atmosphere can be used.

  Examples of the metal catalyst include nickel (Ni), palladium (Pd), platinum (Pt), ruthenium (Ru), Ni—Fe alloy, Ni—Co alloy, Fe—Co alloy, Ni—Cu alloy, Pd— Pt alloy etc. can be mentioned.

(Electrolyte layer)
As the electrolyte layer 12, a metal oxide having oxygen ion conductivity and functioning as a solid electrolyte can be used.

For example, YSZ (yttria stabilized zirconia: Zr _1-x Y _x O ₂ ), SSZ (scandium stabilized zirconia: Zr _1-x Sc _x O ₂ ), SDC (samarium-doped ceria: Ce _1-x Sm _x O _2), GDC (gadolinium doped _{ceria: Ce 1-x Gd x O} 2), LSGM ( lanthanum strontium magnesium _{gallate: La 1-x Sr x Ga} 1-y Mg y O 3) , and the like.

(Cathode electrode)
Examples of the constituent material of the cathode electrode 13 include perovskite oxides.
Examples of the perovskite oxide include perovskite oxides (for example, LSCF (lanthanum strontium cobalt iron oxide), LSM (lanthanum strontium manganese oxide), and the like.

(Porous metal support)
The porous metal support 14 supports the fuel cell unit 1.
The porous metal support 14 can be a metal porous body having many continuous pores.

  Examples of the metal porous body include those obtained by solidifying metal particles or metal fibers by sintering or pressing, or those obtained by forming holes in a metal plate by etching or mechanical treatment, etc. Can be used.

  Examples of the metal material constituting the metal porous body include metal materials such as stainless steel, iron (Fe), nickel (Ni), copper (Cu), platinum (Pt), and silver (Ag). it can.

  The fuel cell unit 1 can be formed by laminating on one surface of the porous metal support 14. The stacking method of the fuel cell unit 1 may be either a dry method or a wet method.

  Examples of the dry method include DC heating vapor deposition, ion beam vapor deposition, reactive ion beam vapor deposition, dipole sputtering, magnetron sputtering, reactive sputtering, tripolar sputtering, ion beam sputtering, and ion plating. Examples thereof include a ting method, a hollow cathode beam method, an ion beam implantation method or a plasma CVD method, and a method in which these methods are arbitrarily combined.

  In addition, examples of the wet method include inkjet, dispenser, roll coater, screen printing, and a method in which these are arbitrarily combined. The wet method can be formed by forming a film using a slurry material or a paste material.

<Contact material layer>
The contact material layer 2 is a porous body that joins the cathode electrode 13 and a conductive portion of a current collecting auxiliary layer 3 described later and has continuous pores that allow air to flow through the cathode electrode 13.

  The members constituting the current collection auxiliary layer 3 often have unevenness and warpage, and when the current collection auxiliary layer 3 and the separator are welded and joined, wrinkles are likely to occur.

  Since the fuel cell unit including the solid oxide electrolyte used for SOFC and the current collecting auxiliary layer 3 are both hard members, when the cathode electrode 13 and the current collecting auxiliary layer 3 are brought into direct contact, the cathode electrode 13 and a current collecting auxiliary layer 3 cause a gap, increasing the contact resistance.

  Therefore, if the current collecting auxiliary layer 3 is strongly pressed against the cathode electrode 13 and compressed so that no gap is generated between the cathode electrode 13 and the current collecting auxiliary layer 3, the fuel cell unit 1 is damaged by the pressing force. End up.

  By providing the contact material layer 2 between the cathode electrode 13 and the current collection auxiliary layer 3, the contact material layer 2 absorbs unevenness and warpage of the current collection auxiliary layer 3, and the bonding surface with the cathode electrode 13 is flattened. Therefore, there is no gap between the cathode electrode and the current collecting auxiliary layer, and these can be joined well and the electric resistance can be reduced.

A cross-sectional view taken along AA ′ in FIG. 1 is shown in FIGS. 3 and 4. FIG. 5 shows an enlarged view of a portion surrounded by a black circle in FIG.
As shown in FIGS. 3 and 4, the contact material layer 2 is disposed between the conductive portion 31 of the current collection auxiliary layer 3 and the cathode electrode 13 along the conductive portion 31 of the current collection auxiliary layer 3. It is formed in a shape substantially the same as the shape of the portion 31.

  The contact material layer 2 is formed along the conductive portion 31 of the current collection auxiliary layer 3, and the gas corresponding to the gas flow hole 32 of the current collection auxiliary layer 3 is not provided with the contact material layer 2. Since the air flowing through the flow holes 32 reaches the cathode electrode 13 directly without passing through the contact material layer 2, the power generation efficiency can be improved.

  Further, since the contact material layer is a porous body having continuous pores, as shown in FIG. 5, not only in the cathode electrode but also in the contact material layer 2, the cathode electrode 13 is joined to the current collecting auxiliary layer 3. The air can be supplied via the, and power generation using the cathode electrode 13 can be performed.

  In the case where the contact material layer is not provided, as shown in FIG. 6, since the air passing through the cathode electrode is not supplied to the joint portion of the cathode electrode 13 with the current collecting auxiliary layer 3, It is difficult to generate power in the area indicated by the white semicircle in 6.

  The porosity of the porous contact material layer 2 is preferably 30 to 40%. When the porosity is within the above range, both air flowability and bondability can be achieved.

  The porosity of the contact material layer is measured by photographing an arbitrary cross section of the contact material layer, binarizing the photographed image by contrast, and distinguishing metal oxide particles from the voids to occupy voids per unit area. This can be done by determining the area ratio.

  As a material constituting the contact material layer 2, a material that can reduce the contact resistance with the cathode electrode 13 by sintering together with the cathode electrode 13 can be used.

Specifically, boron oxide (B ₂ O ₃ ), zinc oxide (ZnO), vanadium oxide (V ₂ O ₅ ), molybdenum oxide (MoO ₃ ), and metal oxide particles functioning as the solid electrolyte are included. These can be used, and these can be used alone or in combination.

  When the contact material layer 2 contains the same metal oxide as the metal oxide of the cathode electrode 13, the contact material layer 2 functions as a cathode electrode and becomes a sintered body integrated with the cathode electrode. The contact resistance between 13 and the contact material layer 2 is reduced. Furthermore, it is difficult for peeling to occur, and the electric resistance can be reduced over a long period of time.

  The contact material layer 2 is a porous material in which the organic binder and the like are lost by mixing the metal oxide particles with an organic binder, an organic solvent or the like in an ink form or a paste form and sintering the mixture. A contact material layer can be formed.

  Specifically, the contact material layer 2 collects an ink / paste contact material layer coating solution by printing using a screen that matches the shape of the conductive portion 31 of the current collection auxiliary layer 3. It is applied to the conductive portion 31 of the auxiliary layer. And it can form by sintering in the state which pinched | interposed the said contact material layer coating liquid on the cathode electrode 13, and the current collection auxiliary | assistant layer 3 and the cathode electrode 13. FIG.

  Moreover, the conductive material 31 of the current collecting auxiliary layer penetrates the contact material layer 2 and is bonded to the cathode electrode 13 by applying the contact material layer coating solution so that the surface to be bonded to the cathode electrode is flat. Protruding to the surface is prevented.

  The thickness of the contact material layer 2 is not particularly limited as long as the current collecting auxiliary layer 3 absorbs unevenness and warpage and no gap is formed between the current collecting auxiliary layer 3 and the cathode electrode 13. The width of the conductive portion 31 of the auxiliary layer 3 is preferably 1/7 to 1/1 times, and more preferably 1/5 to 1/1 times.

  When the thickness of the contact material layer 2 is 1/7 or more of the width of the conductive portion 31 of the current collecting auxiliary layer, the contact material is also provided at the location where the conductive portion 31 of the current collecting auxiliary layer of the cathode electrode 13 is joined. Sufficient air flows through the layer 2, and the cathode electrode 13 can be effectively used to improve power generation efficiency.

  When the thickness of the contact material layer 2 exceeds 1 times the width of the conductive portion 31 of the current collection auxiliary layer, the thickness of the entire fuel cell unit cell becomes thick, and the power generation efficiency per unit volume may be reduced. .

  In the present invention, the thickness of the contact material layer 2 refers to the distance from the cathode electrode surface (flat surface) to the conductive portion of the current collecting auxiliary layer, and the depth at which the conductive portion of the current collecting auxiliary layer is buried in the contact material layer. Does not include minute thickness.

It is preferable that the width of the contact material layer 2 is 1 to 1.5 times the width of the conductive portion of the current collecting auxiliary layer where the contact material layer is joined.
Since the width of the contact material layer 2 is 1 or more times the width of the conductive portion 31 at the joining portion, the cathode electrode 13 and the current collecting auxiliary layer 3 can be reliably joined, and exceeds 1.5 times. The air supply efficiency to the cathode electrode 13 may be reduced.

  In the present invention, the width of the conductive portion of the current collecting auxiliary layer serving as a reference for the thickness or width of the contact material layer 2 refers to the width of the conductive portion in the cross section when the fuel cell unit is cut in the stacking direction.

<Current collection auxiliary layer>
The current collecting auxiliary layer 3 facilitates the movement of electric charges of the cathode electrode 13 to reduce the electric resistance of the entire fuel cell single cell. The current collecting auxiliary layer 3 and the gas flow hole 32 penetrating the conductive portion 31 made of a metal material in the stacking direction. It has.

  As a member constituting the current collecting auxiliary layer 3, for example, an expanded metal shown in FIG. 8, a punching metal shown in FIG. 9, a metal mesh shown in FIG. 10, and a part of a flat plate shown in FIG. A cantilever spring or the like having many gas flow holes penetrating in the stacking direction can be used.

  As a metal material which comprises the current collection auxiliary | assistant layer 3, the thing similar to the metal material which comprises the said metal porous body can be used.

  The size of the gas flow holes 32 of the current collection auxiliary layer 3 is the width of the gas flow path defined by the current collector 4 described later, that is, the wave shape of the current collector 4 joined to the current collection auxiliary layer 3. It is smaller than the space | interval of a convex part of this.

  Since the cathode electrode 13 and the contact material layer 2 are made of a metal oxide having a higher electric resistance than a metal, if the distance that the electric charge moves in the cathode electrode or the contact material layer is long, the fuel cell stack Power generation efficiency will decrease.

By providing the current collection auxiliary layer 3 having a gas flow hole smaller than the width of the gas flow path, the charge of the cathode electrode 13 moves to the current collector 4 through the conductive portion 31 of the current collection auxiliary layer 3. To do.
Therefore, since the distance that the electric charge moves in the cathode electrode and the contact material layer is shortened, the electric resistance can be lowered.

The conductive portion 31 of the current collecting auxiliary layer, that is, the line width is preferably 0.05 mm to 0.15 mm, and more preferably 0.1 mm to 0.15 mm.
The SOFC has a high operating temperature and is easily formed with an oxide film. In particular, the oxide film is formed on the cathode side for supplying oxygen gas, and the electrical resistance is likely to increase.

  If the width of the conductive portion is less than 0.05 mm, the surface area is large and the contact area with air is large, so that the current collection auxiliary layer is oxidized and the electrical resistance is likely to increase.

  In addition, when the width of the conductive portion exceeds 0.15 mm, the distance that the oxygen-containing gas wraps around the portion of the cathode electrode 13 that joins the conductive portion 31 of the current collecting auxiliary layer becomes longer and is used in the cathode electrode. Difficult parts may occur and power generation efficiency may decrease.

Further, the porosity of the gas flow holes 32 of the current collection auxiliary layer 3 is preferably 30% to 80%, and more preferably 30% to 50%.
If it is less than 30%, it is difficult to supply air to the cathode electrode, and if it exceeds 80%, the distance that the electric charge moves in the cathode electrode or the contact material layer becomes long.

As shown in FIG. 4, it is preferable that a part of the fuel cell unit in the stacking direction is buried and joined to the contact material layer 2 in the conductive portion 31 of the current collection auxiliary layer.
Since part of the conductive portion 31 is buried in the contact material layer 2, the contact resistance between the current collection auxiliary layer 3 and the contact material layer 2 is reduced, and the current collection auxiliary layer 3 and the contact material layer 2 Can be joined firmly.

  If the resistance increases due to contact resistance or oxide film at a small joint area, the electrical resistance of the entire system increases significantly, but the conductive portion 31 enters the contact material layer 2 and joins to prevent an increase in electrical resistance. it can.

  As a method of forming a joint in which a part of the conductive part is buried in the contact material layer, an ink-like / paste-like contact material layer coating solution is applied to the conductive part of the current collecting auxiliary layer, and then the contact material layer It can be formed by causing the coating liquid to flow into the gas flow holes or pressing the contact material layer coating liquid applied to the conductive portion of the current collecting auxiliary layer against the cathode electrode.

<Current collector>
The current collector 4 electrically joins the current collecting auxiliary layer 3 and the porous metal support 14 of the adjacent fuel cell single cell, and defines the air flow path CG and the fuel gas flow path AG. Is.

  The current collector 4, the current collection auxiliary layer 3, and the porous metal support 14 of the fuel cell single cell adjacent to the current collector 4 are joined by welding or brazing.

  Metal joints joined by welding or brazing are used to connect the current collecting auxiliary layer, the current collector, and the metal materials constituting the porous metal support directly and / or through other metal materials. Are integrated in a continuous manner, and have no oxide film inside.

  By integrating and continuing the metal materials, air does not enter the interior of the metal joint, and an oxide film can be prevented from being formed inside the metal joint.

  Therefore, the electrical resistance between the current collection auxiliary layer 3 and the current collector 4 and the porous metal support 14 of the fuel cell single cell adjacent to the current collector 4 can be kept low, and the power generation efficiency Can be improved.

The current collector 4 can be formed by pressing a flat plate made of a metal material into a corrugated shape.
As the metal material constituting the current collector 4, the same metal material as that constituting the metal porous body can be used.

<Fuel cell stack>
A plurality of the fuel cell single cells of the present invention can be stacked to form a fuel cell stack.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to the following Example.

[Example 1]
On a powder sintered plate made of stainless steel (Fe—Cr) as a porous metal support, an anode electrode made of cermet of nickel (Ni) and yttria stabilized zirconia (YSZ), a solid electrolyte layer made of YSZ, A cathode electrode made of lanthanum strontium cobalt ferrite (LSCF) was laminated in this order to form a fuel cell unit.

  A current collector made of stainless steel was welded to the porous metal support of the fuel cell unit, and an expanded metal made of stainless steel as a current collecting auxiliary layer was laminated and welded on the current collector.

  Next, lanthanum strontium cobalt ferrite (LSCF), ethyl cellulose as a binder, and butyl acetate as a viscosity modifier were mixed to produce a contact material layer screen printing paste having a viscosity of 200 Pa · s.

  The contact material layer screen printing paste was applied by screen printing on the wire opposite to the expanded metal current collector.

  The surface to which the expanded metal paste was applied was pressed against the electrode surface of the cathode electrode of another separately formed fuel cell unit, and a part of the expanded metal wire was buried in the paste and laminated.

  The laminate was fired to sinter the paste to form a fuel cell stack in which the cathode electrode and the expanded metal (current collection auxiliary layer) were joined by the contact material layer.

  The contact material layer of the fuel cell stack has a thickness that is 1/5 times the width of the conductive portion of the current collecting auxiliary layer, a width that is 1.2 times the width of the conductive portion of the current collecting auxiliary layer, and a porosity of 35%. Met.

[Example 2]
A fuel cell stack was formed in the same manner as in Example 1 except that the thickness of the contact material layer was changed to 1/7 times the width of the conductive portion of the current collecting auxiliary layer.

[Comparative Example 1]
A fuel cell stack was formed in the same manner as in Example 1 except that the contact material layer was not formed.

The fuel cell stack power generation test evaluation of Examples 1 and 2 and Comparative Example 1 was performed.
The evaluation results are shown in FIG.

  It can be seen from the graph of cell voltage-current density in FIG. 12 that the power generation efficiency is improved by providing the contact material layer of the present invention.

DESCRIPTION OF SYMBOLS 1 Fuel cell unit 11 Anode electrode 12 Electrolyte layer 13 Cathode electrode 14 Porous metal support body 2 Contact material layer 3 Current collection auxiliary layer 31 Conductive part 32 Gas distribution hole 4 Current collector 5 Frame 6 Seal CG Air flow path AG Fuel gas Flow path H Manifold part C Fuel cell single cell

Claims (11)

A fuel comprising a fuel cell unit in which an anode electrode, an electrolyte layer, and a cathode electrode are laminated in order, a contact material layer, a current collecting auxiliary layer, and a current collector that is joined to the current collecting auxiliary layer to form an air flow path. A single battery cell,
On the cathode electrode side of the fuel cell unit, a contact material layer, a current collecting auxiliary layer, and a current collector are sequentially laminated,
The current collecting auxiliary layer has a gas flow hole and a conductive portion penetrating in the stacking direction of the fuel cell unit;
A fuel cell single cell, wherein the contact material layer is a porous body formed between a conductive portion of the current collection auxiliary layer and a cathode electrode.   2. The fuel cell single cell according to claim 1, wherein the contact material layer includes a material constituting the cathode electrode.   3. The fuel cell single cell according to claim 1, wherein the contact material layer and the cathode electrode are an integral sintered body.   The fuel according to any one of claims 1 to 3, wherein a thickness of the contact material layer is 1/7 to 1/1 times a width of a conductive portion of the current collecting auxiliary layer. Single battery cell.   5. The fuel cell according to claim 1, wherein a width of the contact material layer is 1 to 1.5 times a width of a conductive portion of the current collection auxiliary layer. Single cell. The part of the stacking direction of the fuel cell unit of the conductive portion of the current collection auxiliary layer is buried and joined in the contact material layer. A fuel cell single cell as described in 1.   The fuel cell single cell according to any one of claims 1 to 6, wherein a porosity of the contact material layer is 30 to 40%.   The fuel cell single cell according to any one of claims 1 to 7, wherein a width of a conductive portion of the current collection auxiliary layer is 0.05 mm to 0.15 mm. The fuel cell single cell according to any one of 1 to 8, wherein the current collection auxiliary layer has a porosity of 30% to 80%. A fuel cell stack comprising a plurality of fuel cell single cells stacked,
A fuel cell stack, wherein the single fuel cell is the single fuel cell according to any one of claims 1 to 9. The fuel cell unit of the fuel cell single cell is supported by a porous metal support,
11. The current collecting auxiliary layer, the current collector, and a porous metal support of a fuel cell single cell adjacent to the current collector are joined by welding or brazing. The fuel cell stack described.

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