JP2017168245A - Electrochemical cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrochemical cell which can be easily positioned when fixing to an insertion hole of a manifold.SOLUTION: A fuel cell 10 includes: a body 11; and a gas flow path 12 formed inside the body 11 and extending in a first direction. The width of the body 11 in a second direction perpendicular to the first direction gradually narrows from a central portion 11a toward a first end portion 11b.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an electrochemical cell.

  Conventionally, a cell stack including a plurality of fuel cells, which are a kind of electrochemical cell, and a manifold that supports each fuel cell is known (for example, Patent Document 1). Each fuel cell is formed in a flat plate shape. One end of each fuel cell is fixed in a state of being inserted into the manifold.

Japanese Patent Laying-Open No. 2015-164094

  By the way, when the one end of the fuel cell is inserted into the manifold and fixed, it is not always easy to position the fuel cell in the state of being inserted into the manifold. Such a problem is not limited to the fuel cell, and similarly occurs in all electrochemical cells including an electrolytic cell.

  An object of the present invention is to provide an electrochemical cell that can be easily positioned when being fixed to an insertion hole of a manifold.

  The electrochemical cell according to the present invention includes a main body portion and a gas flow path formed in the main body portion and extending in the first direction. The width of the main body portion in the second direction perpendicular to the first direction gradually decreases from the central portion toward the first end portion.

  ADVANTAGE OF THE INVENTION According to this invention, when fixing to the insertion hole of a manifold, the electrochemical cell which can be positioned easily can be provided.

Perspective view of fuel cell stack Top view of fuel cell Fuel cell side view AA sectional view of FIG.

(Configuration of fuel cell stack 100)
FIG. 1 is a perspective view of the fuel cell stack 100. The fuel cell stack 100 includes a plurality of fuel cells 10 and a manifold 20.

  Each fuel cell 10 is supported by a manifold 20. One end of each fuel cell 10 is inserted into an insertion hole 21 formed in the manifold 20. One end of each fuel cell 10 is fixed to the manifold 20 by a bonding material (not shown) (for example, amorphous glass). The other end of each fuel cell 10 is a free end. The fuel cells 10 are arranged at a predetermined interval, and are electrically connected to each other by a current collecting member (not shown) (for example, oxide ceramics or metal). The number of fuel cells 10 and the number of rows can be changed as appropriate.

  The manifold 20 supports each fuel cell 10. The manifold 20 is formed in a hollow shape. The manifold 20 has a fuel introduction path 22 for introducing fuel gas therein. The fuel gas introduced into the manifold 20 is supplied to the fuel cell 10.

  During operation of the fuel cell stack 100, high-temperature fuel gas (such as hydrogen) is introduced into the manifold 20, and oxygen-containing gas (such as air) passes through the gaps between the fuel cells 10.

(Configuration of fuel cell 10)
Next, the configuration of the fuel cell 10 will be described with reference to the drawings. FIG. 2 is a plan view of the fuel cell 10. FIG. 3 is a side view of the fuel cell 10.

  As shown in FIGS. 2 and 3, the fuel cell 10 includes a main body 11 and a plurality of gas flow paths 12. The fuel cell 10 is a so-called horizontal stripe type solid oxide fuel cell.

1. Body 11
The main body 11 is formed in a flat plate shape. The main body 11 has a main surface (plate surface) 11S. The size of the main body 11 is not particularly limited, but the length in the first direction can be 5 cm to 50 cm, the width in the second direction perpendicular to the first direction can be 1 cm to 10 cm, The thickness in the third direction (not shown in FIG. 2, see FIG. 4) perpendicular to the direction and the second direction can be 1 mm to 5 mm. In the present embodiment, the first direction is the longitudinal direction of the main body 11, the second direction is the short direction of the main body 11, and the third direction is the thickness direction of the main body 11.

  The main body 11 includes a central portion 11a, a first end portion 11b, and a second end portion 11c. The central part 11a is located at the center of the main body part 11 in the first direction. The first end portion 11b is located at one end of the main body portion 11 in the first direction. The second end portion 11c is located at the other end of the main body portion 11 in the first direction. The first end portion 11b is located on the opposite side of the second end portion 11c.

  The main body portion 11 is formed in a tapered shape from the central portion 11a toward the first and second end portions 11b and 11c in a plan view of the main surface 11S. That is, the width of the main body portion 11 in the second direction is gradually narrowed from the central portion 11a toward the first end portion 11b. Further, the width of the main body portion 11 in the second direction is gradually narrowed from the central portion 11a toward the second end portion 11c.

  The width Wa of the central portion 11a is larger than the width Wb of the first end portion 11b. Therefore, in the cross section perpendicular to the first direction, the cross-sectional area of the main body portion 11 gradually increases from the first end portion 11b toward the central portion 11a. The ratio (Wb / Wa) of the width Wb of the first end portion 11b to the width Wa of the central portion 11a may be less than 1.0 and is not particularly limited. In view of facilitating positioning of the fuel cell 10, the ratio (Wb / Wa) is preferably 0.94 or less, more preferably 0.92 or less, and particularly preferably 0.90 or less. On the other hand, if the width of the central portion 11a where the temperature rises easily is increased, the outer surface area of the central portion 11a is increased and the heat dissipation is improved, so that the overall temperature distribution of the main body portion 11 can be made uniform. Considering this point, the ratio (Wb / Wa) is preferably 0.94 or more, more preferably 0.92 or more, and particularly preferably 0.90 or more.

  The width Wa of the central portion 11a is larger than the width Wc of the second end portion 11c. Accordingly, in the cross section perpendicular to the first direction, the cross-sectional area of the main body portion 11 gradually decreases from the central portion 11a toward the second end portion 11c. The ratio (Wc / Wa) of the width Wc of the first end portion 11c to the width Wa of the central portion 11a is not particularly limited as long as it is less than 1.0. In consideration of making the temperature distribution of the main body part 11 uniform by widening the central part 11a, the ratio (Wc / Wa) is preferably 0.94 or more, more preferably 0.92 or more, and 90 or more is particularly preferable.

  In the present embodiment, the width Wb of the first end portion 11b is equal to the width Wc of the second end portion 11c. However, the width Wb of the first end portion 11b may be smaller than the width Wc of the second end portion 11c, or may be larger than the width Wc of the second end portion 11c.

  Moreover, the main-body part 11 is formed in the taper shape toward the 1st and 2nd end parts 11b and 11c from the center part 11a also in the side view. That is, the thickness of the main body 11 in the third direction is gradually reduced from the central portion 11a toward the first end portion 11b. Further, the thickness of the main body 11 in the third direction is gradually reduced from the central portion 11a toward the second end portion 11c.

  The thickness Ta of the central portion 11a is larger than the thickness Tb of the first end portion 11b. Therefore, in the cross section perpendicular to the first direction, the cross-sectional area of the main body portion 11 gradually increases from the first end portion 11b toward the central portion 11a. The ratio (Tb / Ta) of the thickness Tb of the first end portion 11b to the thickness Ta of the central portion 11a may be less than 1.0 and is not particularly limited. In consideration of facilitating positioning of the fuel cell 10, the ratio (Tb / Ta) is preferably 0.95 or less, more preferably 0.90 or less, and particularly preferably 0.85 or less. On the other hand, if the thickness of the central portion 11a is increased to narrow the gap between the fuel cells 10, the flow rate of air passing through the gap between the fuel cells 10 increases, so that the cooling efficiency of each fuel cell 10 can be improved. . Considering this point, the ratio (Tb / Ta) is preferably 0.95 or more, more preferably 0.90 or more, and particularly preferably 0.85 or more.

  The thickness Ta of the central portion 11a is larger than the thickness Tc of the second end portion 11c. Accordingly, in the cross section perpendicular to the first direction, the cross-sectional area of the main body portion 11 gradually decreases from the central portion 11a toward the second end portion 11c. The ratio (Tc / Ta) of the thickness Tc of the first end portion 11c to the thickness Ta of the central portion 11a may be less than 1.0 and is not particularly limited. In consideration of improving the cooling efficiency of the fuel cell 10 by increasing the thickness of the central portion 11a, the ratio of the thickness Tc of the first end portion 11c to the thickness Ta of the central portion 11a is preferably 0.95 or more. 0.90 or more is more preferable, and 0.85 or more is particularly preferable.

  In the present embodiment, the thickness Tb of the first end portion 11b is equal to the thickness Tc of the second end portion 11c. However, the thickness Tb of the first end portion 11b may be smaller than the thickness Tc of the second end portion 11c, or may be larger than the thickness Tc of the second end portion 11c.

2. Multiple gas flow paths 12
The plurality of gas flow paths 12 are formed inside the main body 11. Each gas flow path 12 extends along the first direction. The gas flow paths 12 are arranged in the second direction.

  Each gas flow path 12 opens to the first end portion 11 b and the second end portion 11 c of the main body portion 11. The fuel gas flows in from the opening on the first end portion 11b side, and flows out from the opening on the second end portion 11c side.

  In the present embodiment, as shown in FIG. 2, five gas flow paths 12 are provided in the main body 11, but the number, size, and position of the gas flow paths 12 can be changed as appropriate.

(Internal structure of fuel cell 10)
Next, the internal structure of the fuel cell 10 will be described with reference to the drawings. 4 is a cross-sectional view taken along line AA in FIG.

  The fuel cell 10 includes a support substrate 2, a fuel electrode 3, a solid electrolyte layer 4, a reaction preventing layer 5, an air electrode 6, an air electrode current collecting layer 7, and an interconnector 8. The fuel electrode 3, the solid electrolyte layer 4, the reaction preventing layer 5, the air electrode 6, the air electrode current collecting layer 7, and the interconnector 8 constitute a power generation unit 13. The solid electrolyte layer 4 covers the entire region of the support substrate 2 other than the power generation unit 13. The support substrate 2 and the solid electrolyte layer 4 constitute a main body 11.

  The support substrate 2 is formed in a flat plate shape. The support substrate 2 is a main part of the main body 11. Accordingly, the width of the support substrate 2 in the second direction is gradually narrowed from the central portion toward both end portions. A gas flow path 12 is provided inside the support substrate 2. The fuel gas flowing through the gas flow path 12 is supplied to the fuel electrode 3 through the inside of the support substrate 2. The thickness of the support substrate 2 is not particularly limited, but can be 1 mm to 5 mm. The porosity of the support substrate 2 is not particularly limited, but can be 20% to 60% in a reducing atmosphere.

The support substrate 2 contains an electrically insulating porous material as a main component. As a material constituting the support substrate 2, MgO (magnesium oxide), a mixture of MgAl ₂ O ₄ (magnesia alumina spinel) and MgO (magnesium oxide), CSZ (calcia stabilized zirconia), 8YSZ (yttria stabilized zirconia), Insulating ceramics such as Y ₂ O ₃ (yttria) and CZO (calcium zirconate) can be used. In the present specification, “containing as a main component” means containing 80% by weight or more of the target component.

  The support substrate 2 may contain a transition metal or an oxide of the transition metal that functions as a catalyst for promoting a reforming reaction of the fuel gas. Ni (nickel) is preferred as the transition metal.

  The fuel electrode 3 functions as an anode. The anode 3 includes an anode current collecting layer 31 and an anode active layer 32.

The anode current collecting layer 31 is disposed on the support substrate 2. The anode current collecting layer 31 is made of a material containing NiO and having electron conductivity. The fuel electrode current collector 31 may contain a substance having oxygen ion conductivity. The anode current collecting layer 31 can be made of, for example, NiO-8YSZ, NiO—Y ₂ O ₃ , NiO—CSZ, or the like. The thickness of the fuel electrode current collector 31 is not particularly limited, but may be 50 μm to 500 μm. The anode current collector 31 may be porous, and the porosity is not particularly limited, but may be 25% to 50%.

  The anode active layer 32 is disposed on the anode current collecting layer 31. The anode active layer 32 is composed of a substance having electron conductivity and a substance having oxygen ion conductivity. The anode active layer 32 can be made of, for example, NiO-8YSZ, NiO-GDC (gadolinium-doped ceria), or the like. The volume ratio of the substance having oxygen ion conductivity in the anode active layer 32 is preferably larger than the volume ratio of the substance having oxygen ion conductivity in the anode current collector 31. The thickness of the anode active layer 32 is not particularly limited, but can be 5 μm to 30 μm. The porosity of the anode active layer 32 is not particularly limited, but can be 25% to 50%.

  The solid electrolyte layer 4 is disposed between the fuel electrode 3 and the air electrode 6. In the present embodiment, the solid electrolyte layer 4 covers the entire region of the support substrate 2 other than the power generation unit 13. The solid electrolyte layer 4 together with the interconnector 8 constitutes a sealing film for preventing mixing of the fuel gas supplied to the fuel electrode 3 and the air supplied to the air electrode 6.

  The solid electrolyte layer 4 can contain zirconia as a main component. As a material constituting the solid electrolyte layer 4, for example, 3YSZ, 8YSZ, ScSZ (scandia stabilized zirconia) or the like can be used. The thickness of the solid electrolyte layer 4 is not particularly limited, but can be 3 μm to 50 μm.

  The reaction preventing layer 5 is disposed on the solid electrolyte layer 4. As a material constituting the reaction preventing layer 5, for example, a ceria-based material containing ceria and a rare earth metal oxide solid-dissolved in ceria can be used. Examples of such ceria-based materials include GDC and SDC (Samarium-doped ceria). The thickness of the reaction preventing film 5 is not particularly limited, but can be 3 μm to 50 μm.

The air electrode 6 is disposed on the reaction preventing layer 5. Examples of the material constituting the air electrode 6 include (La, Sr) (Co, Fe) O ₃ (LSCF, lanthanum strontium cobalt ferrite), (La, Sr) FeO ₃ (LSF, lanthanum strontium ferrite), La ( Ni, Fe) O ₃ (LNF, lanthanum nickel ferrite), (La, Sr) CoO ₃ (LSC, lanthanum strontium cobaltite), and the like. The thickness of the air electrode 6 is not particularly limited, but can be 10 to 100 μm.

  The air electrode current collecting layer 7 is formed on the air electrode 6. The air electrode current collecting layer 7 is connected to the interconnector 8 of another adjacent power generation unit 13. The air electrode current collecting layer 7 is made of a porous material having electron conductivity. The air electrode current collecting layer 7 can be made of, for example, LSCF, LSC, Ag (silver), Ag—Pd (silver palladium alloy), or the like. The thickness of the air electrode current collecting layer 7 is not particularly limited, but may be 50 μm to 500 μm.

The interconnector 8 is disposed on the fuel electrode 3. The interconnector 8 is connected to the air electrode current collecting layer 7 of another adjacent power generation unit 13. The interconnector 8 is a dense layer compared to the support substrate 2 and the fuel electrode 3. The interconnector 8 can be composed of, for example, LaCrO ₃ (lanthanum chromite), (Sr, La) TiO ₃ (strontium titanate), or the like. The interconnector 8 only needs to be denser than the fuel electrode 3, and the porosity is not particularly limited, but is preferably 20% or less, more preferably 10% or less. The thickness of the interconnector 8 is not particularly limited, but can be 10 μm to 100 μm.

(Manufacturing method of fuel cell stack 100)
Next, an example of a method for manufacturing the fuel cell stack 100 will be described.

  First, a molded body of the support substrate 2 having a plurality of gas flow paths 12 is formed by extrusion molding, compacting molding or tape molding of the above-described support substrate material. At this time, the support substrate 2 is formed so that the width of the formed body gradually decreases from the central portion toward both end portions. When the molded body of the support substrate 2 is formed by extrusion molding, a rectangular parallelepiped molded body may be formed by extrusion molding and then cut into a desired drum shape.

  Next, the above-described fuel electrode material is made into a paste and screen-printed on the formed body of the support substrate 2 to form the formed body of the fuel electrode 3.

  Next, the interconnector material is made into a paste and screen-printed on the molded body of the fuel electrode 3 to form the interconnector 8 molded body.

  Next, the solid electrolyte material 4 is formed on the support substrate 2 and the fuel electrode 3 by dip molding to form a solid electrolyte layer 4 compact. Next, the reaction preventive layer 5 is formed on the solid electrolyte layer 4 by dip forming the reaction preventive layer material.

  Next, the molded bodies of the support substrate 2, the fuel electrode 3, the solid electrolyte layer 4, the reaction preventing layer 5, and the interconnector 8 are co-fired (1300 to 1600 ° C., 2 to 20 hours).

  Next, the air electrode material is made into a paste and screen-printed on the reaction preventing layer 5 to form a molded body of the air electrode 6. Next, the air electrode current collecting layer material is formed into a paste and screen-printed on the air electrode 6 shaped body to form the air electrode current collecting layer 7 shaped body. Next, the molded object of the air electrode 6 and the air electrode current collection layer 7 is baked (900-1100 degreeC, 1 to 20 hours). Thus, the fuel cell 10 is manufactured.

  Next, the manifold 20 is prepared, and each of the plurality of fuel cells 10 is inserted into the insertion hole 21 using a jig. At this time, since the width of the main body portion 11 of the fuel cell 10 is gradually narrowed from the central portion 11a toward the first end portion 11b, the fuel cell 10 can be removed by simply inserting the first end portion 11b into the insertion hole 21. It can be easily positioned.

  Next, a paste of, for example, an amorphous material (for example, amorphous glass) is applied around the first end portion 11b. Next, the applied paste is solidified by heat treatment (800 ° C. to 1050 ° C., 1 hour to 10 hours).

(Function and effect)
(1) In the fuel cell 10 according to the present embodiment, the width of the main body 11 in the second direction gradually decreases from the central portion 11a toward the first end portion 11b.
Therefore, since the first end portion 11b can be fitted into the insertion hole 21 by inserting the first end portion 11b into the insertion hole 21, the fuel cell 10 can be easily positioned.
Further, since the cross-sectional area of the central portion 11a is larger than the cross-sectional area of the first end portion 11b, the flow rate of the fuel gas from the first end portion 11b toward the central portion 11a is reduced. Therefore, the power generation efficiency of the fuel cell 10 can be improved by efficiently supplying the fuel gas to the power generation unit 13. Furthermore, the overall temperature distribution of the main body 11 can be made uniform by increasing the width of the central portion 11a, which is likely to rise in temperature, and improving the heat dissipation of the central portion 11a.

(2) In the fuel cell 10, the width of the main body portion 11 in the second direction is gradually narrowed from the central portion 11a toward the second end portion 11c.
Therefore, the temperature distribution of the main body 11 can be made uniform by increasing the width of the central portion 11a.

(3) In the fuel cell 10, the thickness of the main body portion 11 in the third direction is gradually reduced from the central portion 11a toward the first end portion 11b.
Therefore, by inserting the first end portion 11b into the insertion hole 21, the first end portion 11b can be fitted into the insertion hole 21, so that the fuel cell 10 can be positioned more easily. Further, the cooling efficiency of the fuel cell 10 can be improved by increasing the thickness of the central portion 11a to narrow the gap between the fuel cells 10 and increasing the flow velocity of air passing through the gap between the fuel cells 10. it can.

  (4) In the fuel cell 10, the thickness of the main body 11 in the third direction gradually decreases from the central portion 11a toward the second end portion 11c. Therefore, the cooling efficiency of the fuel cell 10 can be improved by increasing the thickness of the central portion 11a and narrowing the gap between the fuel cells 10.

(Other embodiments)
The present invention is not limited to the embodiment described above, and various modifications or changes can be made without departing from the scope of the present invention.

  In the above embodiment, the case where the main body according to the present invention is applied to a solid oxide fuel cell has been described. However, the main body according to the present invention is not only a solid oxide fuel cell but also a solid oxide electrolytic cell. It is applicable to a solid oxide electrochemical cell containing

  In the said embodiment, although the width | variety in the 2nd direction of the main-body part 11 decided to become narrow gradually toward the 2nd end part 11c from the center part 11a, toward the 2nd end part 11c from the center part 11a. It may be constant.

  In the said embodiment, although the width | variety of the center electric power generation part 13a was larger than the width | variety of the terminal electric power generation part 13b, it may be comparable as the width | variety of the terminal electric power generation part 13b.

  In the above embodiment, the solid electrolyte layer 4 is a sealing film that covers the outer surface of the support substrate 2, but the present invention is not limited to this. The seal film covering the outer surface of the support substrate 2 may be made of a dense material other than the solid electrolyte material. In this case, the sealing film only needs to be integrally connected to the solid electrolyte layer 4.

  Although not particularly mentioned in the above embodiment, the gas flow path 12 formed inside the main body 11 may gradually become thicker from the first end 11b toward the center 11a. Thereby, the flow rate of the fuel gas can be further reduced.

2 Support Substrate 3 Fuel Electrode 4 Solid Electrolyte Layer 5 Reaction Prevention Layer 6 Air Electrode 7 Air Electrode Current Collection Layer 8 Interconnector 10 Fuel Cell 11 Main Body 11a Central Part 11b First End 11c Second End 11S Main Surface 12 Gas Flow path 13 Power generation unit 13a Central power generation unit 13b First terminal power generation unit 13c Second terminal power generation unit 20 Manifold 21 Insertion hole 100 Fuel cell stack

Claims (4)

The main body,
A gas channel formed inside the main body and extending in the first direction;
With
The width of the main body in the second direction perpendicular to the first direction is gradually narrowed from the center toward the first end,
Electrochemical cell. The width of the main body portion in the second direction is gradually narrowed from the central portion of the main body portion toward the second end portion,
The electrochemical cell according to claim 1. The main body,
A gas channel formed inside the main body and extending in the first direction;
With
The thickness of the main body portion in the third direction perpendicular to the first direction and the second direction perpendicular to the first direction gradually decreases from the central portion of the main body portion toward the first end portion. ,
Electrochemical cell. The thickness of the main body portion in the third direction is gradually reduced from the central portion of the main body portion toward the second end portion,
The electrochemical cell according to claim 3.

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