JP2006012453A - Solid oxide fuel cell stack and solid oxide fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid oxide fuel cell stack capable of preventing electrical connection failures between a collector and a cell by the densification or deviation of the collector or between separators and having a collector structure performing good conductivity, and a solid oxide fuel cell equipped with such a stack. <P>SOLUTION: When a plurality of cell boards 2 each equipped with a cell and a support part 2a supporting the cell, separators 3 electrically connecting electrodes 2b, 2c of the adjoining cell boards 2 and a collector 4 are laminated alternately, the collector 4 and the electrodes 2b, 2c of the cell and the collector 4 and the separator 3 are physically joined by adhesive layers 5, 6 made of conductive paste. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a parallel plate type solid oxide fuel cell (SOFC), and more particularly, ensures energization between flat plate type single cells, and lowers energization characteristics due to deformation due to thermal stress caused by temperature change and the like. The present invention relates to a solid oxide fuel cell stack having a current collecting structure capable of preventing the above and a solid oxide fuel cell comprising such a cell stack.

  In recent years, for example, fuel cells that use air and hydrogen as oxidant gas and fuel gas, respectively, and directly convert the chemical energy inherent in the fuel gas into electrical energy have attracted attention from the viewpoint of resource saving and environmental protection. In particular, a solid oxide fuel cell using a solid oxide as an electrolyte material has many advantages such as high power generation efficiency and effective use of waste heat.

  FIG. 14 shows a conventional internal manifold type flat solid oxide fuel cell. In addition, the internal manifold system means that a gas supply / exhaust hole for a fuel gas and an oxidant gas is provided in a separator of a solid oxide fuel cell and the like, and each electrode surface of each flat cell is connected through these holes. It refers to the one that supplies and exhausts gas.

A flat solid oxide fuel cell 100 shown in the figure has an air electrode 104 made of (La, Sr) MnO _{3 on} both surfaces of a flat solid electrolyte 102 made of a zirconia sintered body (YSZ) doped with yttria or the like. And a flat unit cell 108 in which a fuel electrode 106 made of NiO-YSZ cermet is disposed, and adjacent flat unit cells 108 are electrically connected in series, and fuel gas and oxidant are connected to the flat unit cell 108. It consists of a separator 110 that distributes and supplies gas, and a mesh-like metal 115 is disposed between the separator 110 and the fuel electrode 106, and a connection layer 117 is disposed between the separator 110 and the air electrode 104. The separator 110, the fuel electrode 106, and the air electrode 104 are electrically connected with each other, and a sealing material 119 is provided on the side surface. Closed.
Then, the flat solid oxide fuel cells 100 are alternately stacked, and an oxidant gas and a fuel gas are respectively introduced from the flow path 114, and these are formed on the surfaces of the air electrode 104 and the fuel electrode 106 of each flat cell 108. An electromotive force is generated by bringing an oxidant gas and a fuel gas into contact with each other and output from the solid oxide fuel cells 100 stacked in series.

  At this time, the current collecting surface of the separator 110 has a flat surface formed by machining or the like, whereas the flat cell 108 has warpage or distortion generated during manufacturing. Since it is difficult to perform a mechanical process and correct it to a complete plane from the relationship, when the separator 110 is attached to the flat cell 108, the flat cell 108 has a current collecting surface and a surface of the separator 110. The contact cannot be made as a whole, and it may become a point contact and a good electrical connection state may not be obtained. In addition, when a plurality of the unit cells 108 are stacked, the tightening load is applied to the flat unit cell 108 via the ceramic separator 110. Therefore, the tightening force changes due to temperature fluctuation, and the load becomes excessive. In such a case, the separator 110 and the flat cell 108 may be destroyed. Further, in order to cope with the deformation, the conductive metal 115 for electrically connecting the flat unit cells 108 must be strengthened, and this also applies a load to the flat unit cells 108 and is caused by thermal stress or the like. It is conceivable that the flat cell 108 is damaged.

In order to solve such a problem, a current collecting structure for a fuel cell has been proposed in which a metal plate having a convex portion is elastically brought into contact with an air electrode and a fuel electrode to relieve stress applied to the cell simultaneously with current collection. (For example, refer to Patent Document 1).
Further, a method using a conductive felt as a current collecting structure has been proposed (see, for example, Patent Documents 2 and 3).
JP 2001-68132 A JP-A-01-012469 Japanese Patent Laid-Open No. 06-203857

However, the conventional solid oxide fuel cell stack structure generally has the following problems.
(1) Rigid current collection with conductive ceramics, etc., may damage the cell due to stress due to heat distribution in the stack.
(2) Even with elastic contact using a thin metal plate, stress may be applied to the cell, leading to cell damage.
(3) In the current collecting structure as described above, in order to ensure the strength so that the cell is not damaged, it is necessary to take measures such as thickening the cell, and the stack becomes heavy and large.
(4) If only the conductive felt is pressed, the felt is densified by heat, and the contact property may be deteriorated due to the deterioration of the cushioning property or deformation.
(5) Although there is a method of inserting an elastic body to press the conductive felt, an elastic body that can stably maintain elasticity under the temperature environment of SOFC is very expensive, and the stack is increased in size and weight. It leads to.

  The present invention has been made by paying attention to the above-described problems in the current collecting structure of a conventional solid oxide fuel cell stack, and the object of the present invention is to collect the current collector by densification or displacement of the current collector In addition to a solid oxide fuel cell stack with a current collecting structure that can prevent poor electrical connection between the cell and separator, and exhibit good electrical conductivity, solid oxide incorporating such a stack The object is to provide a physical fuel cell.

  In order to achieve the above object, the present inventors have conducted extensive studies on the stack structure of the stack, the material and shape of the current collector and separator, and further the intervening layer formed between the cell and separator. The present inventors have found that the above-mentioned problems can be solved not only by pressing between the current collector and the electrodes and separators but also by joining them together, thereby completing the present invention.

  That is, the solid oxide fuel cell stack according to the present invention includes a plurality of cell plates provided with a cell and a support part that supports the cell, and a separator and a current collector that electrically connect the electrodes of the cell. The layers are alternately stacked, and one or both of the current collector and the cell electrode and between the current collector and the separator, for example, by welding or adhesive, or through a welding layer such as a brazing material. The solid oxide fuel cell of the present invention is characterized by including the fuel cell stack of the present invention.

According to the present invention, even if a stack component such as a cell or a separator is distorted or a current collector is densified or deformed, the separator and the current collector, the current collector and the cell electrode Are not in contact with each other but are physically joined to each other, so that stable electrical conduction can be obtained, current collection loss can be reduced, and battery output can be improved. .
Further, it is not necessary to strongly press the current collector against the cell, and the stress applied to the cell can be reduced, so that the cell can be prevented from being damaged and the reliability of the stack is improved. Since the stress applied to the cell is small, the cell can be made thin and light, and the fuel cell stack can be reduced in weight and size. By applying such a stack, the solid oxide fuel cell The output per unit volume can be improved.

  Hereinafter, the solid oxide fuel cell stack of the present invention will be described in more detail.

As described above, the solid oxide fuel cell stack according to the present invention has an alternately laminated structure of a plurality of cell plates, separators, and current collectors, and the current collector is physically attached to one or both of the cell electrodes and separators. The current collector is not only in contact with the electrode or separator by simple pressing, but also physically connected to the electrode and separator, so that the current collector is stable. Electrical continuity can be ensured.
In the present invention, the cell plate is convenient for alternately laminating one or a plurality of cells (single cells) formed by sandwiching a solid oxide electrolyte between both electrodes with a separator and a current collector, This means that the structure is supported by a frame-shaped support part. The support part is not only a separate structure from the cell structure, but also has an electrode layer formed on both sides of a support substrate made of an electrolyte material. Has an electrolyte layer and the other electrode layer (air electrode layer) formed on a support substrate made of an electrode material (for example, a fuel electrode material) or an electrode material (for example, a fuel electrode material). (Electrode support type) is also included.

  As the current collector, it is desirable to use a metal felt in view of its flexibility, elasticity, electrical conductivity, bondability, etc., and the current collector is preferably bonded to both the electrode and the separator. Needless to say. However, for example, in the case of metal-to-metal contact, the contact resistance does not increase so much, so even if it is not necessarily bonded to both, as long as only one of them is physically bonded, the other contact state As long as it is ensured, a corresponding effect can be obtained.

Here, “physically joining” means strong joining by, for example, welding, adhesion, brazing or the like.
Welding is a process in which materials to be joined are melted together and joined directly. For example, resistance welding, laser welding, spot arc welding, or the like can be applied to joining a current collector and a separator. .

  In addition, it is desirable that the adhesive used for bonding is conductive, and for example, a conductive paste mainly composed of Pt can be used. However, the adhesive is limited only to such a conductive adhesive. It is not something.

That is, the adhesive does not necessarily have conductivity as long as the electrode portion of the cell and the current collector, and the current collector and the separator can sufficiently contact each other. In addition, the adhesive does not form a stack structure by itself, and has an adhesive strength that can prevent the current collector from being dissociated from the electrode or the separator due to distortion or deformation at high temperatures. It is enough.
Furthermore, the component of the conductive paste is not limited to the above-described Pt, and it is sufficient that the conductive paste has conductivity in the atmosphere on the electrode side. Pd, Ag, Au, Ni, Ru, W or an alloy of these metals can be applied.

  And in addition to the welding and adhesion described above, like soldering, it is melted by energizing treatment or heat treatment, filled between the electrode and the current collector, between the current collector and the separator, and solidified to join them together. It is also possible to perform physical bonding with a weld layer using metal.

The metal forming such a weld layer is lower than the melting point of the material to be joined, in this case, the electrode, current collector and separator, and higher than the operating temperature of the solid oxide fuel cell. It is necessary to have a melting point, and what is generally called a brazing material, for example, a metal such as Pt, Ag, Au, Pd, Ni, or an alloy containing these metals as a main component may be used. If possible, it is desirable to include a component that forms a strong oxide film on the surface of the weld layer, such as Al, Si, Cr, and the like.
Furthermore, it is also desirable that the oxide contains a metal having electron conductivity, such as Sn, Zn, Ga, etc., so that the welded layer is oxidized by the gas atmosphere (air electrode side). However, it becomes possible to maintain conductivity.

Such a welding layer can be formed in a single layer or multiple layers by, for example, PVD (physical vapor deposition) processing such as sputtering or EB deposition or plating.
In addition, when the weld layer has a multilayer structure, it is inexpensive but excellent in oxidation resistance by forming a layer containing a large amount of material such as Pd that is expensive but excellent in oxidation resistance only on the surface side. Bonding layer can be obtained

In joining the current collector and the cell electrode by the adhesive as described above or the weld layer, it is desirable to form the mesh on the electrode surface without forming the adhesive or the weld layer on the entire surface of the electrode, This ensures gas supply to the electrode.
Further, at this time, it is desirable that the electrode contains at least one of the components contained in the adhesive or the welding layer, and the presence of a common component with the electrode material in the adhesive or the welding layer. , A stronger bond is possible.

The heat-resistant alloy used as the separator material generally has a mechanism of improving its heat resistance by forming an oxide film such as Si or Al on the surface at high temperatures. Becomes a factor of increasing electrical resistance in the contact portion.
On the other hand, in the present invention, the contact portion that requires electrical continuity is covered with a welded layer made of an adhesive (conductive paste) or brazing metal, so that the contact resistance due to the growth of the oxide film is reduced. The increase is prevented.

  Hereinafter, the present invention will be specifically described based on examples. Needless to say, the present invention is not limited to these examples.

Example 1
1 to 4 show a first embodiment of the present invention, and a solid oxide fuel cell stack 1 according to the embodiment supports an electrolyte 2a as shown in FIG. 1 (a). The cell plate 2 having the electrolyte-supporting fuel cell serving as the substrate is electrically connected to the cells of the adjacent cell plates 2 and the gas between the fuel electrode 2b and the air electrode 2c of the cell plate 2 is separated. It has a structure in which a large number of separators 3 and current collectors 4 electrically connected in series between the cells of the cell plate 2 and the separators 3 are alternately stacked.

The cell plate 2 has a thickness of about 100 μm and a size of about 120 mm square, and is positioned at the center of the electrolyte 2a that is a support substrate, and is formed with electrodes 2b and 2c to contribute to power generation ( Cell) and a support part that forms a gas seal part and a gas flow path while supporting the power generation part when stacked, and the outer periphery of the electrolyte 2a also functions as a support part of the cell. It has become.
As shown in FIG. 2, four manifolds, that is, a fuel gas supply manifold 2d, an air supply manifold 2e, a fuel gas exhaust manifold 2f, and an air exhaust manifold 2g are formed on the support portion of the cell plate 2. .

The electrolyte 2a is made of stabilized zirconia (YSZ) to which 8 mol% of yttria is added, and also serves as a support portion as described above. Power generation unit is a approximately 100mm square, the fuel electrode 2b mainly composed of NiO-YSZ on one side, the air electrode 2c mainly composed of _{LSM (La 1-X Sr X} MnO 3) on the other side Both are baked to a thickness of about 50 μm.
As shown in FIG. 2, an adhesive layer 5 made of a conductive paste (conductive adhesive) mainly composed of a noble metal, for example, Pt powder, is formed in a mesh shape on both the electrodes 2b and 2c. ing.

As shown in FIG. 3, the separator 3 is made of a heat-resistant alloy having a thickness of 5 mm, and includes an air flow path 3 a having a depth of 2 mm on one side and a fuel flow path 3 b having a depth of 2 mm on the other side. Similarly, a fuel gas supply manifold 3d, an air supply manifold 3e, a fuel gas exhaust manifold 3f, and an air exhaust manifold 3g are formed in a portion overlapping the support portion of the fuel cell, and each manifold 2d, 2e of the cell plate 2 is formed. 2f and 2g, respectively.
A fuel cell stack 1 is formed by alternately laminating the separators 3 and the fuel cell plates 2, and air is supplied to the air electrode 2c side, and air is supplied to the fuel electrode 2b side and exhausted. .

In the fuel cell stack 1, the current collector 4 is interposed between the cell and the separator 3 in order to electrically connect the electrodes 2 b and 2 c of the cell plate 2 and the separator 3.
The current collector 4 is made of, for example, a metal felt knitted with a heat-resistant metal fiber having excellent heat resistance, between the separator 3 and the current collector 4, and between the current collector 4 and the cell electrode 2b, Since it is desirable to have electrical conductivity during 2c, as described above, the adhesive layers 5 and 6 made of conductive paste, which is an adhesive having Pt powder as a main component and having heat resistance, It is joined in a state as shown in FIG.

  Next, a manufacturing procedure of the above-described solid oxide fuel cell stack 1 will be described with reference to FIGS.

First, using an electrolyte material, in this example, 8YSZ slurry, a green sheet is produced by the doctor blade method, cut into a predetermined size, drilled to form each manifold, and then fired. Thus, an electrolyte substrate (electrolyte) 2a having a thickness of about 100 μm is produced.
Next, as shown in FIG. 4A, the fuel electrode material and the air electrode material are applied to the front and back surfaces of the substrate 2a by screen printing, and then fired to form the fuel electrode 2b and the air electrode 2c. The cell plate 2 is used.

  Next, as shown in FIG. 4B, a conductive paste is applied in a mesh pattern by screen printing on the fuel electrode 2b and the air electrode 2c to form the adhesive layer 5. It is desirable that the paste application width (mesh width) at this time is such that gas diffusion within the electrode is not alienated, that is, about twice the thickness of the electrode layer.

On the other hand, the separator 3 is made into a shape as shown in FIGS. 3 and 4C by using a heat-resistant metal as described above, by cutting, pressing, etching, or the like, but the manufacturing method is particularly limited. Not.
And as shown in FIG.4 (d), with respect to the obtained separator 3, the electrically conductive paste is apply | coated to the surface which contacts the electrical power collector 4, and the adhesive bond layer 6 is formed.

  And finally, after laminating the cell plate 2, the separator 3, and the current collector 4 shown in FIG. 4 (e), the current collector 4 is made by, for example, applying heat treatment at about 800 ° C. and baking the conductive paste. By physically joining both the cell of the cell plate 2 and the separator 3, a solid oxide fuel cell stack 1 is obtained as shown in FIG. 4 (f).

  In the first embodiment, since the electrodes 2b and 2c of the cell plate 2 and the current collector 4, and the current collector 4 and the separator 3 are connected by a conductive adhesive, the stack components 2 and 3 are strained. Even if the current collector 4 is deformed and the current collector 4 is deformed, stable electrical conduction is obtained, and the battery output can be improved by reducing the current collection loss. In addition, since electrical continuity can be stably obtained without strongly pressing the current collector against the cell, even if each member is made thinner and lighter, the reliability of the stack is not impaired, and the fuel cell stack is reduced in weight. It is possible to realize downsizing.

  In the above-described embodiment, the example in which the adhesive layers 6 and 5 are formed on the cell electrodes 2b and 2c and the separator 3, respectively. However, the method for forming the adhesive layer is limited to such a method. For example, it is also possible to form an adhesive layer on both sides of the current collector 4 by applying a bonding material to both sides of the current collector 4 or by dipping the current collector 4 into an adhesive. is there.

Moreover, in the said Example, although the example using the cell board 2 provided with the electrolyte support type cell was shown, it is not limited to this, It is possible to apply also to an electrode support type cell.
FIG. 5 shows an example in which an electrode supporting cell is applied to the above embodiment. In this example, as shown in FIGS. 5 (a) and 5 (b), an electrode (fuel electrode) supporting cell is shown. A metal frame 7 is joined to the outer peripheral portion as a support portion, and this cell plate is laminated as shown in FIG. As shown, the electrode 2c and the current collector 4, and the current collector 4 and the separator 3 are joined. Note that manifolds 7d, 7e, 7f, and 7g for gas supply and exhaust are also formed on the frame 7 as the support portion.

(Example 2)
6 and 7 show a second embodiment of the present invention. In the solid oxide fuel cell stack 1 according to the embodiment, as shown in FIGS. 6 (a) to 6 (c). By coating the entire current collector 4 made of heat-resistant metal felt with a Pt alloy, a weld layer 8 is formed on the surface of the current collector fiber, and the current collector 4 is connected to the electrode 2b via the weld layer 8. 2c and the separator 3 are different from the first embodiment.
In this embodiment, as shown in FIG. 7, since the current collector 4 in which the weld layer 8 is pre-coated on the fiber surface is used, it is laminated between the separator 3 and the cell plate 2 as it is. In this state, just by heat treatment, the welded layer 8 melts and enters between the electrodes 2b, 2c and the separator 3, and the parts can be joined as shown in FIG. Simplification of the process can be achieved. In addition, bonding is also performed at the contact portion between the fibers constituting the current collector 4, and the number of good electrical connection points also increases inside the current collector 4, thereby reducing the electrical resistance of the current collector itself. The effect to reduce can also be acquired.

  The coating can be performed by PVD treatment such as sputtering or EB vapor deposition, or plating. Especially when electrolytic plating is used, a thick film tends to be formed on the outer periphery of the current collector 4 due to its characteristics. Therefore, the weld layer 8 can be efficiently formed at the joint portion between the separator 4 and the electrodes 2b and 2c.

Example 3
FIG. 8 shows a third embodiment of the present invention. In this embodiment, the cell electrode, for example, the air electrode 2c, has heat resistance and is also included in the weld layer 8. The Pt powder, which is a metal, is dispersed and is basically the same as Example 2 except for this.
As described above, by dispersing the metal powder having higher electron conductivity in the electrode, the electron conductivity in the electrode is improved, and a metal-metal bond is interposed between the current collector 4 and the electrode 2c. As a result, electrical resistance is low and strong bonding is possible.

  In each of the above-described embodiments, the same method is used for joining the current collector 4 and the separator 3 and joining the current collector 4 and the cell electrodes 2b and 2c. However, the same joining method is not necessarily used. It is not necessary to apply, and an optimum joining method in consideration of the material and shape can be adopted.

Example 4
9 and 10 show a fourth embodiment of the present invention. In this embodiment, the separator 3 and the current collector 4 are joined together by welding as shown in FIG. The body 4 and the electrodes 2b and 2c are joined together with the conductive paste as in the first embodiment.

  FIG. 10 shows the production procedure. In this example, first, the separator 3 and the current collector 4 are welded by, for example, a spot. At this time, the entire contact surface of the separator 3 and the current collector 4 may be welded. However, since the respective electrical resistance is low, the spot-shaped welding has almost no influence on the current collecting resistance of the stack. For bonding the cell plate 2 and the current collector 4, as in the first embodiment, a conductive paste was applied to the surfaces of the electrodes 2 b and 2 c by screen printing to form an adhesive layer 5. After that, these are similarly laminated and subjected to heat treatment to join the current collector 4.

In this embodiment, the fuel cell stack 1 can be manufactured at a low cost by joining the conductive parts such as the separator 3 and the current collector 4 by a simple technique of welding. In this embodiment, the bonding between the electrodes 2b and 2c and the separator 3 uses an adhesive. However, the bonding is not limited to this, and the bonding is performed via the welding layer 8 as shown in the second embodiment. However, the same effect can be obtained.
At this time, a weld layer made of brazing metal can be formed on the separator 3 side, and it is also desirable to form a weld layer on both joint surfaces of the separator 3 and the current collector 4 as necessary.

(Example 5)
11 to 13 show a fifth embodiment of the present invention. In this embodiment, the cathode (air electrode) side current collecting structure has a structure in which the air electrode, the metal support, and the current collector are electrically connected by the weld layer, and the current collector is welded to the separator. This is different from the first embodiment.
In this embodiment, as shown in FIGS. 11 (a) and 11 (b), the cell plate 2 has four single cells mounted on a metal frame 7 as a support portion and is made of a conductive adhesive. The cathode layer (air electrode 2 c) is electrically connected to the metal frame 7 by the adhesive layer 5.

As shown in FIG. 12, one end of a columnar current collector 10 is joined to the surface of the separator 3 by welding, and the current collector 10 joined to the cathode side surface of the metal frame 7 and the separator 3. As shown in FIG. 13, they are joined by an adhesive layer 5 made of a conductive adhesive.
A current collector 4 made of metal felt is sandwiched between the anode electrode (fuel electrode 2b) of the cell and the separator 3, and is joined by a conductive adhesive (not shown).

  In general, on the side of the cathode electrode 2c that is in a high-temperature oxidation atmosphere, the material that can achieve both flexibility and electrical resistance of the connection portion under such conditions is limited to a special material such as a metal mainly composed of a noble metal. Naturally, it becomes expensive. However, according to the embodiment, it is possible to use an inexpensive material with low oxidation resistance as the current collector 10 instead of such an expensive current collecting material. Further, even when a highly rigid member such as a thick wire is used to reduce electrical resistance, the stress on the cell is small, and the occurrence of cracks, breakage, etc. can be prevented.

(A) It is sectional drawing which shows the 1st Example of the solid oxide fuel cell stack of this invention. (B) It is an expanded sectional view explaining the structure of the current collection part of the fuel cell stack shown to Fig.1 (a). It is a top view explaining the shape of the cell board in the fuel cell stack shown in FIG. It is the top view (a) and sectional drawing (b) explaining the shape of the separator in the fuel cell stack shown in FIG. It is process drawing explaining the manufacturing procedure of the fuel cell stack shown in FIG. It is explanatory drawing which shows the example which replaced the cell board in the fuel cell stack shown in FIG. 1 with the electrolyte support type cell. (A) It is an expanded sectional view explaining the structure of the current collection part in the 2nd Example of the solid oxide fuel cell stack of this invention. (B) It is explanatory drawing which shows the state before heat processing of the current collection part shown to Fig.6 (a). (C) It is explanatory drawing which shows the state after heat processing of the current collection part shown to Fig.6 (a). It is process drawing explaining the manufacturing procedure of the fuel cell stack concerning the 2nd Example of this invention. It is an expanded sectional view explaining the current collection part structure in the 3rd Example of the solid oxide fuel cell stack of this invention. It is an expanded sectional view explaining the current collection part structure in the 4th Example of the solid oxide fuel cell stack of this invention. It is process drawing explaining the manufacturing procedure of the fuel cell stack concerning the 4th Example of this invention. It is the top view (a) and sectional drawing (b) explaining the shape of the cell board used for the 5th Example of the solid oxide fuel cell stack of this invention. It is the top view (a) and sectional drawing (b) explaining the shape of the separator used for the 5th Example of the solid oxide fuel cell stack of this invention. (A) It is sectional drawing which shows the 5th Example of the solid oxide form fuel cell stack of this invention. (B) It is an expanded sectional view explaining the structure of the current collection part of the fuel cell stack shown to Fig.13 (a). It is sectional drawing which shows the structure of the flat type solid oxide fuel cell of the conventional internal manifold system.

Explanation of symbols

1 Solid oxide fuel cell stack 2 Cell plate 2a Electrolyte (support)
2b Fuel electrode 2c Air electrode 3 Separator 4 Current collector 5 Adhesive layer 6 Adhesive layer 7 Frame (support part)
8 Welding layer 9 Metal powder 10 Current collector

Claims (16)

In a solid oxide fuel cell stack comprising a cell and a plurality of cell plates having a support portion for supporting the cell, a separator and a current collector for electrically connecting the electrodes of the cell,
A solid oxide fuel cell stack, wherein the current collector is physically joined to the electrode and / or separator of the cell.   2. The solid oxide fuel cell stack according to claim 1, wherein the current collector is a metal felt.   3. The solid oxide fuel cell stack according to claim 1, wherein the current collector is joined to the electrode and / or separator of the cell by welding.   3. The solid oxide fuel cell stack according to claim 1, wherein the current collector is bonded to the electrode and / or separator of the cell with an adhesive.   5. The solid oxide fuel cell stack according to claim 4, wherein the current collector is bonded to at least an electrode of the cell, and the adhesive is formed in a mesh shape on the electrode surface.   6. The solid oxide according to claim 4, wherein the current collector is bonded to at least an electrode of the cell, and at least one component included in the adhesive is contained in the electrode. Fuel cell stack.   The solid oxide fuel cell stack according to any one of claims 4 to 6, wherein the adhesive has conductivity.   The solid oxide fuel cell stack according to claim 1 or 2, wherein the current collector is joined to the electrode and / or separator of the cell via a welded layer.   9. The welding layer according to claim 8, wherein the weld layer is a metal selected from the group consisting of Pt, Pd, Au, Ag, and Ni, or an alloy containing at least one metal selected from the group. Solid oxide fuel cell stack.   10. The solid oxide fuel cell stack according to claim 8, wherein the weld layer contains a metal that forms an oxide film on the surface thereof in an oxidizing atmosphere.   The solid oxide fuel cell stack according to claim 10, wherein the oxide film has electronic conductivity.   The solid oxide fuel cell stack according to any one of claims 8 to 11, wherein the welding layer is formed in a single layer or a multilayer by plating.   The solid oxide fuel cell stack according to any one of claims 8 to 11, wherein the welding layer is formed in a single layer or a multilayer by a PVD method.   The solid oxide according to any one of claims 8 to 13, wherein the current collector is bonded to at least an electrode of a cell, and a welded layer is formed in a mesh shape on the electrode surface. Fuel cell stack.   The said collector is joined to the electrode of the cell at least, The at least 1 sort (s) of component contained in the welding layer is contained in the said electrode, The statement of any one of Claims 8-14 characterized by the above-mentioned. 2. A solid oxide fuel cell stack according to 1.   A solid oxide fuel cell comprising the fuel cell stack according to any one of claims 1 to 15.

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