JP2012209067A - Solid oxide fuel cell stack and method for manufacturing solid oxide fuel cell stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid oxide fuel cell stack which obtains high output by preventing the occurrence of a voltage loss due to warpage of a separator, and to provide a method for manufacturing the solid oxide fuel cell stack.SOLUTION: The solid oxide fuel cell stack comprises: a first fuel battery cell laminate; a second fuel battery cell laminate; a radiator plate provided between the first fuel battery cell laminate and the second fuel battery cell laminate; a first insulation plate provided between a first separator of the first fuel battery cell laminate, which is located at a side close to the radiator plate, and the radiator plate; and a second insulation plate provided between a second separator of the second fuel battery cell laminate, which is located at a side close to the radiator plate, and the radiator plate. The first separator and the second separator are electrically connected. The method for manufacturing the solid oxide fuel cell stack is also disclosed.

Description

  The present invention relates to a solid oxide fuel cell stack and a method for manufacturing a solid oxide fuel cell stack.

  In recent years, solid oxide fuel cell stacks that convert chemical energy of fuel into electrical energy have attracted attention as a highly efficient and clean power generation device.

  FIG. 8 shows a schematic perspective view of a solid oxide fuel cell stack disclosed in Patent Document 1 of the related art. As shown in FIG. 8, the solid oxide fuel cell stack described in Patent Document 1 is a solid oxide fuel cell stack 100 in which solid oxide fuel cells 101 and separators 102 are alternately stacked. And the solid oxide fuel cell stack 200 in which the solid oxide fuel cells 201 and the separators 202 are alternately stacked are connected via a heat sink 300.

Each of the solid oxide fuel cells 101 and 102 includes a solid electrolyte layer made of an oxide ion conductor, an air electrode layer (cathode) and a fuel electrode layer (anode) provided on both sides of the solid electrolyte layer, respectively. have. Then, air is supplied to the air electrode layers of the solid oxide fuel cells 101 and 102, and hydrogen gas is supplied to the fuel electrode layer, whereby reaction equations (i) and (ii) shown below are obtained. Electricity is generated by the chemical reaction.
Air electrode layer: 1 / 2O ₂ + 2e ⁻ → O ²⁻ (i)
Fuel electrode layer: H ₂ + O ²⁻ → H ₂ O + 2e ⁻ (ii)
Then, the electrons generated by the power generation flow from the solid oxide fuel cell stack 100 to the solid oxide fuel cell stack 200 through the heat sink 300 as shown by the arrows in FIG. Electrical energy is extracted outside the solid oxide fuel cell stack.

JP 2010-186573 A

  In order to extract electric energy efficiently, the solid oxide fuel cell stack is preferably operated in a predetermined temperature range. However, during the operation of the solid oxide fuel cell stack, the temperature of the central portion in the stacking direction of the solid oxide fuel cell stack becomes higher than the temperature of the end portion and exceeds the predetermined temperature range. Sometimes.

  Therefore, the temperature of the central portion in the stacking direction of the solid oxide fuel cell stack is lowered by installing the heat sink 300 at the central portion in the stacking direction of the solid oxide fuel cell stack.

  However, the heat dissipation plate 300 and the solid oxide fuel cells 101 and 201 have different thermal expansion coefficients, and the heat dissipation plate 300 and the separators 102 and 202 have different rigidity due to the difference in shape. As a result, the separators 102 and 202 disposed before and after the heat radiating plate 300 may be warped during operation of the solid oxide fuel cell stack.

  As described above, when the separators 102 and 202 disposed above and below the heat sink 300 are warped, the contact area between the separators 102 and 202 and the heat sink 300 is reduced. , 202 has a problem that voltage loss occurs at the contact point.

  In view of the above circumstances, an object of the present invention is to provide a solid oxide fuel cell stack and a solid oxide fuel cell stack that can suppress the occurrence of voltage loss due to the warp of the separator and can achieve high output. It is to provide a manufacturing method.

  The present invention is provided between the first fuel cell stack, the second fuel cell stack, the first fuel cell stack, and the second fuel cell stack. Each of the first fuel cell stack and the second fuel cell stack includes alternately stacked solid oxide fuel cells, and a separator, The first fuel cell stack includes a first separator located on the side close to the heat sink, and the second fuel cell stack includes a second separator located on the side close to the heat sink. A first insulating plate is provided between the first separator and the heat sink, and a second insulating plate is provided between the second separator and the heat sink. Solid oxide fuel cell device in which the separator and the second separator are electrically connected A click.

  Here, in the solid oxide fuel cell stack of the present invention, it is preferable that the first separator and the second separator are electrically connected by a silver wire.

  In the solid oxide fuel cell stack of the present invention, it is preferable that the first separator, the second separator, and the heat radiating plate are made of the same material.

  In the solid oxide fuel cell stack of the present invention, it is preferable that the first separator, the second separator, and the heat sink are each made of stainless steel.

  Furthermore, the present invention is a method for producing any one of the above solid oxide fuel cell stacks, the step of forming a first fuel cell stack, and the formation of a second fuel cell stack. A step of installing a second insulating plate on the second fuel cell stack, a step of installing a heat sink on the second insulating plate, and a first insulating plate on the heat sink A solid oxidation process comprising: a step of installing; a step of installing the first fuel cell stack on the first insulating plate; and a step of electrically connecting the first separator and the second separator. It is a manufacturing method of a physical fuel cell stack.

  According to the present invention, it is possible to provide a solid oxide fuel cell stack and a method for manufacturing the solid oxide fuel cell stack that can suppress the occurrence of voltage loss due to the warp of the separator and achieve high output. it can.

1 is a schematic perspective view of a solid oxide fuel cell stack according to an embodiment. It is a typical perspective view illustrating a part of manufacturing process of an example of the manufacturing method of the solid oxide fuel cell stack of the present embodiment. It is a typical perspective view illustrating other part of the manufacturing process of an example of the manufacturing method of the solid oxide fuel cell stack of this Embodiment. It is a typical perspective view illustrating other part of the manufacturing process of an example of the manufacturing method of the solid oxide fuel cell stack of this Embodiment. It is a typical perspective view illustrating other part of the manufacturing process of an example of the manufacturing method of the solid oxide fuel cell stack of this Embodiment. It is a typical perspective view illustrating other part of the manufacturing process of an example of the manufacturing method of the solid oxide fuel cell stack of this Embodiment. It is a typical perspective view illustrating other part of the manufacturing process of an example of the manufacturing method of the solid oxide fuel cell stack of this Embodiment. FIG. 6 is a schematic perspective view of a solid oxide fuel cell stack disclosed in conventional Patent Document 1.

  Embodiments of the present invention will be described below. In the drawings of the present invention, the same reference numerals represent the same or corresponding parts.

  FIG. 1 shows a schematic perspective view of a solid oxide fuel cell stack of the present embodiment which is an example of the solid oxide fuel cell stack of the present invention. The solid oxide fuel cell stack shown in FIG. 1 includes a first fuel cell stack 10, a second fuel cell stack 20, a first fuel cell stack 10, and a second fuel cell. And a heat radiating plate 30 provided between the cell laminate 20.

  Here, the first fuel cell stack 10 is configured by alternately stacking solid oxide fuel cells 11 and separators 12. The second fuel cell stack 20 is configured by alternately stacking solid oxide fuel cells 21 and separators 22.

  Further, the first fuel cell stack 10 includes a separator 12 (hereinafter referred to as “first separator 12”) disposed at a position closest to the radiator plate 30 and the radiator plate 30. Insulating plate 40a is provided, separator 22 (hereinafter referred to as "second separator 22") disposed closest to heat radiating plate 30 of second fuel cell stack 20, and heat radiating plate. A second insulating plate 40 b is provided between the second insulating plate 40 and the second insulating plate 40 b.

  Further, the first separator 12 of the first fuel cell stack 10 and the second separator 22 of the second fuel cell stack 20 are electrically connected by a wiring 50.

  In the solid oxide fuel cell stack according to the present embodiment, the first insulating plate 40a is installed between the first separator 12 and the heat radiating plate 30 of the first fuel cell stack 10, and the first A second insulating plate 40 b is installed between the second separator 22 and the heat radiating plate 30 of the second fuel cell stack 20.

  Further, the first separator 12 of the first fuel cell stack 10 and the second separator 22 of the second fuel cell stack 20 are connected by the wiring 50 to thereby connect these electrical connections. Collateral.

  As a result, warpage occurs in the first separator 12 of the first fuel cell stack 10 and the second separator 22 of the second fuel cell stack 20, respectively, and the first separator 12 and the heat sink Even if the contact area with 30 and the contact area between the second separator 22 and the heat sink 30 are reduced, the electrical connection between the first separator 12 and the second separator 22 is secured by the wiring 50. Therefore, no voltage loss occurs between the first separator 12 and the second separator 22. Therefore, the solid oxide fuel cell stack according to the present embodiment can have a higher output than before.

  Hereinafter, an example of a method for manufacturing the solid oxide fuel cell stack of the present embodiment will be described with reference to schematic perspective views of FIGS. In addition, it cannot be overemphasized that another process may be contained between each process mentioned later.

  First, as shown in FIG. 2, a step of forming the first fuel cell stack 10 is performed. The first fuel cell stack 10 can be formed, for example, by alternately stacking solid oxide fuel cells 11 and separators 12 on the first separator 12.

  Here, the stacking of the solid oxide fuel cell 11 and the separator 12 electrically connects the first separator 12 and the solid oxide fuel cell 11 directly above the first separator 12. The solid oxide fuel cell 11 located on the first separator 12 and the separator 12 are also electrically connected.

  In addition, as shown in FIG. 3, a step of forming the second fuel cell stack 20 is performed. In the second fuel cell stack 20, for example, solid oxide fuel cells 21 and separators 22 are alternately stacked, and the second fuel cell stack 20 is placed on the uppermost solid oxide fuel cell 21. Can be formed by installing the separator 22.

  Here, in the lamination of the solid oxide fuel cell 21 and the separator 22, the second separator 22 and the solid oxide fuel cell 21 immediately below the second separator 22 are electrically connected. At the same time, the solid oxide fuel cell 21 located below the second separator 22 and the separator 22 are also electrically connected.

  The order in which the step of forming the first fuel cell stack 10 and the step of forming the second fuel cell stack 20 is not particularly limited, and the first fuel cell stack 10 May be formed first, the second fuel cell stack 20 may be formed first, and the first fuel cell stack 10 and the second fuel cell stack 20 are formed simultaneously. May be.

  In the above, as the solid oxide fuel cells 11 and 21, for example, those having a configuration in which an electrolyte made of a solid oxide is provided between a fuel electrode and an air electrode can be used. The shapes of the solid oxide fuel cells 11 and 21 can be, for example, a plate shape having a polygonal surface or a disk shape.

  The fuel electrode is not particularly limited as long as it functions as a fuel electrode. For example, a Ni cermet fuel electrode having a thickness of 30 μm to 50 μm can be used.

  The air electrode is not particularly limited as long as it functions as an air electrode. For example, an air electrode made of samarium strontium cobaltite (SSC) having a thickness of 30 μm to 50 μm can be used.

  The electrolyte comprising a solid oxide is not particularly limited as long as it is a solid oxide capable of conducting ions such as oxide ions generated by an electrode reaction at the air electrode. For example, zirconia oxide, ceria oxide, lanthanum Electrolytes such as gallate oxides, barium cerate oxides, barium zirconate oxides, strontium serate oxides, strontium zirconate oxides, lanthanum silicate oxides can be used without any particular limitation. Among these, as the electrolyte made of a solid oxide, it is preferable to use a lanthanum gallate oxide represented by the following composition formula (I).

_{La 1-s Sr s Ga 1-} (u + v) Co u Mg v O w ... (I)
In the composition formula (I), s represents a real number satisfying 0 ≦ s ≦ 0.25, u represents a real number satisfying 0 ≦ u ≦ 0.1, and v represents 0.05 ≦ v ≦ 0.25. It is preferable that w represents a real number satisfying 2.7 ≦ w ≦ 3.025.

  The thickness of the electrolyte made of the solid oxide can be, for example, 150 μm or more and 220 μm or less.

  As the separators 12, 22, the first separator 12 and the second separator 22, for example, stainless steel having a thickness of 2 mm or more and 4 mm or less can be used. The shapes of the separators 12, 22, the first separator 12 and the second separator 22 can be, for example, a plate shape having a polygonal surface or a disk shape.

  Next, as shown in FIG. 4, the step of installing the second insulating plate 40 b on the second fuel cell stack 20 is performed. The step of installing the second insulating plate 40b on the second fuel cell stack 20 includes installing the second insulating plate 40b on the second separator 22 of the second fuel cell stack 20. It is done by.

The second insulating plate 40b is not particularly limited as long as it electrically insulates the second separator 22 and the heat radiating plate 30, but electrically insulates the second separator 22 and the heat radiating plate 30. On the other hand, it is preferable to use a material that transfers heat from the second separator 22 to the heat sink 30. As such second insulating plate 40b, for example, alumina (Al ₂ O ₃ ) or the like can be used.

  The shape of the second insulating plate 40b can be, for example, a plate shape having a polygonal surface or a disk shape. Further, the thickness of the second insulating plate 40b can be, for example, 100 μm or more and 200 μm or less.

  Next, as shown in FIG. 5, a step of installing the heat sink 30 on the second insulating plate 40b is performed.

  As the heat sink 30, for example, stainless steel can be used. As the heat radiating plate 30, for example, a plate in which a plurality of columnar members made of stainless steel or the like are arranged radially with a space between a plate-like upper member and lower member made of stainless steel or the like is used. it can.

  Next, as shown in FIG. 6, a step of installing the first insulating plate 40a on the heat radiating plate 30 is performed.

The first insulating plate 40a is not particularly limited as long as it electrically insulates the first separator 12 and the radiator plate 30, but electrically insulates the first separator 12 and the radiator plate 30. However, it is preferable to use a material that transfers heat from the first separator 12 to the heat sink 30. As the first insulating plate 40a, for example, alumina (Al ₂ O ₃ ) or the like can be used.

  The shape of the first insulating plate 40a can be, for example, a plate shape having a polygonal surface or a disk shape. Further, the thickness of the first insulating plate 40a can be, for example, 100 μm or more and 200 μm or less.

  Next, as shown in FIG. 7, a step of installing the first fuel cell stack 10 on the first insulating plate 40a is performed. The step of installing the first fuel cell stack 10 on the first insulating plate 40a is such that the first separator 12 of the first fuel cell stack 10 is on the first insulating plate 40a side. This is done by installing the first fuel cell stack 10 on the first insulating plate 40a.

  Thereafter, as shown in FIG. 1, the first separator 12 of the first fuel cell stack 10 and the second separator 22 of the second fuel cell stack 20 are electrically connected by the wiring 50. By doing so, the solid oxide fuel cell stack of the present embodiment can be manufactured.

  The wiring 50 is not particularly limited as long as it electrically connects the first separator 12 and the second separator 22, but among them, it is preferable to use a silver wire. When a silver wire is used for the wiring 50, the voltage loss between the first separator 12 and the second separator 22 tends to be suppressed.

  The electrical connection method between the wiring 50 and the first separator 12 and the electrical connection method between the wiring 50 and the second separator 22 are not particularly limited as long as they are electrical connection methods. For example, a conventionally known method can be used.

  In addition, in the above, it is preferable that the 1st separator 12, the 2nd separator 22, and the heat sink 30 consist of the same material, respectively. In this case, the material cost of the first separator 12, the second separator 22, and the heat sink 30 tends to be reduced.

  Moreover, in the above, it is preferable that the 1st separator 12, the 2nd separator 22, and the heat sink 30 are each stainless steel. In this case, the conductivity of each of the first separator 12, the second separator 22, and the heat sink 30 during power generation of the solid oxide fuel stack tends to be improved.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention can be used for a solid oxide fuel cell stack and a method for producing a solid oxide fuel cell stack.

  10 First fuel cell stack, 11, 21 Solid oxide fuel cell, 12, 22 Separator, 20 Second fuel cell stack, 30 Heat sink, 40a First insulating plate, 40b Second Insulating plate, 50 wiring, 100,200 solid oxide fuel cell stack, 101,201 solid oxide fuel cell, 102,202 separator, 300 heat sink.

Claims (5)

A first fuel cell stack,
A second fuel cell stack,
A heat sink provided between the first fuel cell stack and the second fuel cell stack,
The first fuel cell stack and the second fuel cell stack each include alternately stacked solid oxide fuel cells and separators,
The first fuel cell stack includes a first separator located on the side closer to the heat sink,
The second fuel cell stack includes a second separator located on the side closer to the heat sink,
A first insulating plate is provided between the first separator and the heat dissipation plate,
A second insulating plate is provided between the second separator and the heat radiating plate,
A solid oxide fuel cell stack, wherein the first separator and the second separator are electrically connected.   2. The solid oxide fuel cell stack according to claim 1, wherein the first separator and the second separator are electrically connected by a silver wire.   3. The solid oxide fuel cell stack according to claim 1, wherein the first separator, the second separator, and the heat sink are made of the same material. 4.   4. The solid oxide fuel cell stack according to claim 3, wherein each of the first separator, the second separator, and the heat sink is made of stainless steel. 5. A method for producing a solid oxide fuel cell stack according to any one of claims 1 to 4,
Forming the first fuel cell stack,
Forming the second fuel cell stack,
Installing the second insulating plate on the second fuel cell stack,
Installing the heat sink on the second insulating plate;
Installing the first insulating plate on the heat sink;
Installing the first fuel cell stack on the first insulating plate;
And a step of electrically connecting the first separator and the second separator. A method for manufacturing a solid oxide fuel cell stack.

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