JP2017117661A - Manifold, and fuel cell stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fill the gap of a manifold body and a lid member securely with a bonding material.SOLUTION: A manifold 20 includes a manifold body 3, a lid member 4, and a first bonding material 5. The manifold body 3 has a bottom wall 31, a sidewall 32 extending upward from the circumference of the bottom wall 31, and a groove 33 extending in the upper surface of the sidewall 32. The lid member 4 closes the upper surface of the manifold body 3. The first bonding material 5 fills the groove 33, and bonds the manifold body 3 and lid member 4. The first bonding material 5 is composed of a glass material. The groove 33 has an arcuate shape in the cross section perpendicular to the extension direction thereof.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a manifold and a fuel cell stack.

  The fuel cell stack includes a manifold and a plurality of fuel cells (Patent Document 1). Each fuel cell is supported by the manifold so as to extend upward from the manifold. The manifold is configured to supply fuel gas to each fuel cell.

  The manifold has a manifold body and a lid member. The lid member is joined to the manifold body and closes the upper surface of the manifold body. Specifically, the bonding material joins the lid member and the manifold body.

Japanese Patent Laying-Open No. 2015-164094

  In the fuel cell stack described above, it is preferable that the bonding material reliably fills the gap between the manifold and the lid member in order to improve the gas tightness of the manifold.

  An object of the present invention is to reliably fill a gap between a manifold body and a lid member with a bonding material.

  The manifold according to the first aspect of the present invention is configured to supply gas to the fuel cells. The manifold includes a manifold body, a lid member, and a first bonding material. The manifold body has a bottom wall, a side wall extending upward from the peripheral edge of the bottom wall, and a groove portion extending from the upper surface of the side wall. The lid member has an insertion hole into which the lower end portion of the fuel battery cell is inserted. The lid member closes the upper surface of the manifold body. The first bonding material is filled in the groove and bonds the manifold body and the lid member. The first bonding material is made of a glass material. The groove has a circular arc shape in a cross section perpendicular to the extending direction of the groove.

  When the first bonding material is subjected to heat treatment, the first bonding material is rounded due to the influence of surface tension, so that the cross-sectional shape becomes a shape along the arc-shaped groove. As a result, the gap between the manifold body and the lid member can be reliably filled with the first bonding material.

  Preferably, the curvature radius of the groove is 1.0 to 10 mm.

  Preferably, the side wall includes a side wall main body portion and a flange portion extending outward from the side wall main body portion. The groove portion extends on the upper surface of the flange portion.

  Preferably, the lid member includes a lid body portion that closes the upper surface of the manifold body, and an insertion portion that extends from the periphery of the lid body portion toward the groove portion.

  Preferably, the groove is annular.

  Preferably, the first bonding material is crystallized glass.

  A fuel cell stack according to a second aspect of the present invention includes any one of the above manifolds and a fuel cell extending upward from a cover member of the manifold.

  According to the present invention, the bonding material can reliably fill the gap between the manifold body and the lid member.

The perspective view of a fuel cell stack. The perspective view of a fuel cell. The expanded sectional view of a fuel cell. Sectional drawing of a fuel cell stack. The top view of a fuel cell stack. The expanded sectional view which shows the groove part of a manifold main-body part. The top view of a cover member. FIG. 6 is a cross-sectional view of a fuel cell stack according to Modification 1. The top view of the lid member concerning the modification 2. FIG. Sectional drawing of the manifold which concerns on each Example. Sectional drawing of the manifold which concerns on each comparative example.

  Hereinafter, an embodiment of a fuel cell stack according to the present invention will be described with reference to the drawings. In FIG. 1, a part of the manifold 20 is shown in cross section for easy illustration.

  As shown in FIG. 1, 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. The manifold 20 supplies gas to each fuel cell 10.

[Fuel battery cell]
Each fuel cell 10 extends upward from the manifold 20. The longitudinal direction (x-axis direction) of the fuel cell 10 extends in the vertical direction. Further, the fuel cells 10 are arranged at intervals from each other along the longitudinal direction (z-axis direction) of the manifold 20. Each fuel battery cell 10 is electrically connected to each other via a current collecting member (not shown). The current collecting member is formed from a conductive material. For example, the current collecting member is formed of a sintered body of oxide ceramics or a metal.

  As shown in FIG. 2, the fuel battery cell 10 includes a plurality of power generation element portions 11 and a support substrate 12. Each power generating element portion 11 is disposed on both surfaces of the support substrate 12. Each power generation element unit 11 may be disposed only on one side of the support substrate 12. The respective power generation element portions 11 are arranged at intervals in the longitudinal direction of the fuel battery cell 10. That is, the fuel cell 10 according to the present embodiment is a so-called horizontal stripe type fuel cell. The power generating element portions 11 are electrically connected to each other by an electrical connection portion 17 (see FIG. 3).

  The support substrate 12 has a plurality of gas flow paths 121 extending in the longitudinal direction of the fuel cell 10 inside. The longitudinal direction (x-axis direction) of the support substrate 12 is the same direction as the longitudinal direction of the fuel cell 10. Each gas channel 121 extends substantially parallel to each other. Each gas flow path 121 is open at both ends in the longitudinal direction of the fuel cell 10.

  As shown in FIG. 3, the support substrate 12 has a plurality of first recesses 123. Each first recess 123 is formed on both surfaces of the support substrate 12. The first recesses 123 are arranged at intervals in the longitudinal direction of the support substrate 12.

The support substrate 12 is insulative. That is, the support substrate 12 does not have electronic conductivity. The support substrate 12 can be made of, for example, CSZ (calcia stabilized zirconia). Alternatively, the support substrate 12 may be composed of NiO (nickel oxide) and YSZ (8YSZ) (yttria stabilized zirconia), or composed of NiO (nickel oxide) and Y ₂ O ₃ (yttria). Alternatively, MgO (magnesium oxide) and MgAl ₂ O ₄ (magnesia alumina spinel) may be used. The support substrate 12 is porous. The porosity of the support substrate 12 is, for example, about 20 to 60%.

  Each power generation element unit 11 includes a fuel electrode 13, an electrolyte 14, and an air electrode 15. Each power generation element unit 11 further includes a reaction preventing film 16. The fuel electrode 13 is a fired body made of a porous material having electron conductivity. The fuel electrode 13 includes a fuel electrode current collector 131 and a fuel electrode active part 132.

  The fuel electrode current collector 131 is disposed in the first recess 123. Specifically, the fuel electrode current collector 131 is filled in the first recess 123 and has the same outer shape as the first recess 123. Each fuel electrode current collector 131 has a second recess 131a and a third recess 131b. The anode active part 132 is disposed in the second recess 131a. Specifically, the fuel electrode active part 132 is filled in the second recess 131a.

The fuel electrode current collector 131 can be composed of, for example, NiO (nickel oxide) and YSZ (8YSZ) (yttria stabilized zirconia). Alternatively, the fuel electrode current collector 131 may be composed of NiO (nickel oxide) and Y ₂ O ₃ (yttria), or composed of NiO (nickel oxide) and CSZ (calcia stabilized zirconia). Also good. The thickness of the fuel electrode current collector 131 and the depth of the first recess 123 are about 50 to 500 μm.

  The fuel electrode active part 132 can be composed of, for example, NiO (nickel oxide) and YSZ (8YSZ) (yttria stabilized zirconia). Alternatively, the fuel electrode active part 132 may be composed of NiO (nickel oxide) and GDC (gadolinium-doped ceria). The thickness of the fuel electrode active part 132 is 5 to 30 μm.

  The electrolyte 14 is disposed so as to cover the fuel electrode 13. Specifically, the electrolyte 14 extends in the longitudinal direction of the fuel cell 10 from one interconnector 171 to another interconnector 171. That is, the electrolyte 14 and the interconnector 171 are alternately arranged in the longitudinal direction of the fuel battery cell 10.

  The electrolyte 14 is a fired body made of a dense material that has ionic conductivity and no electronic conductivity. The electrolyte 14 can be composed of, for example, YSZ (8YSZ) (yttria stabilized zirconia). Or the electrolyte 14 may be comprised from LSGM (lanthanum gallate). The thickness of the electrolyte 14 is, for example, about 3 to 50 μm.

The reaction preventing film 16 is a fired body made of a dense material, has substantially the same shape as the fuel electrode active part 132 in a plan view (viewed in the z-axis direction), and is disposed at substantially the same position as the fuel electrode active part 132. Has been. The reaction preventing film 16 suppresses occurrence of a phenomenon in which a reaction layer having a large electric resistance is formed at the interface between the electrolyte 14 and the air electrode 15 due to a reaction between YSZ in the electrolyte 14 and Sr in the air electrode 15. Is provided. The reaction preventing film 16 can be made of, for example, GDC = (Ce, Gd) O ₂ (gadolinium-doped ceria). The thickness of the reaction preventing film 16 is, for example, about 3 to 50 μm.

The air electrode 15 is disposed on the reaction preventing film 16. The air electrode 15 is a fired body made of a porous material having electron conductivity. The air electrode 15 can be made of, for example, LSCF = (La, Sr) (Co, Fe) O ₃ (lanthanum strontium cobalt ferrite). Alternatively, the air electrode 15 has LSF = (La, Sr) FeO ₃ (lanthanum strontium ferrite), LNF = La (Ni, Fe) O ₃ (lanthanum nickel ferrite), or LSC = (La, Sr) CoO ₃ ( Lanthanum strontium cobaltite) or the like. The air electrode 15 may be composed of two layers of a first layer (inner layer) made of LSCF and a second layer (outer layer) made of LSC. The thickness of the air electrode 15 is, for example, 10 to 100 μm.

The electrical connection portion 17 is configured to electrically connect adjacent power generation element portions 11. The electrical connection portion 17 includes an interconnector 171 and an air electrode current collector film 172. The interconnector 171 is disposed in the third recess 131b. Specifically, the interconnector 171 is embedded (filled) in the third recess 131b. The interconnector 171 is a fired body made of a dense material having electronic conductivity. The interconnector 171 can be composed of, for example, LaCrO ₃ (lanthanum chromite). Alternatively, the interconnector 171 may be made of (Sr, La) TiO ₃ (strontium titanate). The thickness of the interconnector 171 is, for example, 10 to 100 μm.

  The air electrode current collector film 172 is disposed so as to extend between the interconnector 171 and the air electrode 15 of the adjacent power generation element portions 11. For example, the air electrode current collector is connected so as to electrically connect the air electrode 15 of the power generating element unit 11 disposed on the left side of FIG. 3 and the interconnector 171 of the power generating element unit 11 disposed on the right side of FIG. A membrane 172 is disposed. The air electrode current collector film 172 is a fired body made of a porous material having electron conductivity.

The air electrode current collector film 172 can be made of, for example, LSCF = (La, Sr) (Co, Fe) O ₃ (lanthanum strontium cobalt ferrite). Alternatively, the air electrode current collector film 172 may be made of LSC = (La, Sr) CoO ₃ (lanthanum strontium cobaltite). Or the air electrode current collection film | membrane 172 may be comprised from Ag (silver) and Ag-Pd (silver palladium alloy). The thickness of the air electrode current collector film 172 is, for example, about 50 to 500 μm.

[Manifold]
As shown in FIGS. 1 and 4, the manifold 20 is configured to supply gas to each fuel cell 10. A gas such as fuel gas is supplied to the internal space of the manifold 20 through the introduction pipe 201. The manifold 20 supports each fuel cell 10. The manifold 20 includes a manifold body 3, a lid member 4, and a first bonding material 5.

  The manifold body 3 has a rectangular parallelepiped shape and has an internal space whose upper surface is open. The manifold body 3 has a bottom wall 31, a side wall 32, and a groove portion 33. In addition, the bottom wall 31 and the side wall 32 are comprised by one member. The manifold body 3 is formed of a metal having heat resistance, for example. More specifically, the manifold body 3 is formed of at least one selected from the group consisting of ferritic stainless steel, austenitic stainless steel, and Ni-based alloy.

  The bottom wall 31 has a rectangular shape in plan view (viewed in the x-axis direction). The bottom wall 31 has a longitudinal direction (z-axis direction) and a width direction (y-axis direction) in plan view. The side wall 32 extends upward from the peripheral edge of the bottom wall 31. That is, the side wall 32 extends from a pair of edges extending in the longitudinal direction of the bottom wall 31 and a pair of edges extending in the short direction.

  The side wall 32 has a side wall main body 321 and a flange 322. The side wall main body 321 is a portion extending upward from the bottom wall 31. The flange portion 322 is a portion that extends outward from the upper end portion of the side wall main body portion 321. Note that the side wall main body 321 and the flange 322 extend integrally.

  As shown in FIGS. 4 to 6, the groove 33 extends on the upper surface of the side wall 32. Specifically, the groove portion 33 extends on the upper surface of the flange portion 322. The groove 33 is annular in plan view (viewed in the x-axis direction). The groove 33 has a circular arc shape in a cross section orthogonal to the extending direction of the groove 33.

  The groove 33 extends along the direction in which the upper surface of the side wall 32 extends. That is, the groove part 33 extends along the direction in which the flange part 322 extends. Specifically, the groove 33 extends in the longitudinal direction (z-axis direction) and the width direction (y-axis direction) of the manifold 20. Therefore, the groove 33 has a circular arc shape in a cross section perpendicular to the longitudinal direction of the manifold 20 in a portion extending in the longitudinal direction of the manifold 20. Further, the groove 33 has a circular arc shape in a cross section orthogonal to the width direction of the manifold 20 in a portion extending in the width direction of the manifold 20. The radius of curvature of the groove 33 is preferably about 1.0 to 10 mm.

  As shown in FIG. 4, the lid member 4 is configured to close the upper surface of the manifold body 3. The outer peripheral edge portion of the lid member 4 is disposed on the side wall 32 and is bonded to the side wall 32 via a first bonding material 5 described later.

  The lid member 4 has a lid main body 41 and an insertion part 42. The lid body 41 is configured to close the upper surface of the manifold body 3. As shown in FIG. 7, the lid main body 41 has a rectangular shape in plan view (viewed in the z-axis direction). The lid body 41 has a plurality of insertion holes 411. The lower end portion of each fuel cell 10 is inserted into each insertion hole 411. Each insertion hole 411 extends in the width direction (y-axis direction) of the manifold 20. Further, the insertion holes 411 are arranged at intervals in the longitudinal direction of the manifold 20.

  As shown in FIG. 4, the insertion portion 42 extends from the peripheral edge of the lid main body portion 41 toward the groove portion 33. The insertion portion 42 has an annular shape in plan view (viewed in the x-axis direction). The insertion part 42 is inserted into the groove part 33. The insertion portion 42 is formed by bending the peripheral edge portion of the lid main body portion 41 downward.

  The first bonding material 5 is filled in the groove 33 and joins the manifold body 3 and the lid member 4. Specifically, the first bonding material 5 is filled in the groove portion 33 in a state where the insertion portion 42 is inserted. The insertion portion 42 may be inserted into the groove portion 33 after the first bonding material 5 is filled in the groove portion 33, or the first bonding material 5 is inserted into the groove portion 33 after the insertion portion 42 is inserted into the groove portion 33. May be filled.

  In the state where the first bonding material 5 is inserted into the groove 33, it is preferable that the first bonding material 5 completely fills the groove 33. For example, in a state where the first bonding material 5 is inserted into the groove 33, it is preferable that the first bonding material 5 fills the groove 33 with an amount that overflows from the groove 33. In order to cure the first bonding material 5 filled in the groove 33, the first bonding material 5 is subjected to heat treatment. For example, the first bonding material 5 is heated at a temperature of about 750 to 900 ° C. for about 60 to 180 minutes.

The first bonding material 5 includes a glass material. Preferably, the first bonding material 5 is crystallized glass. As the crystallized glass, for example, MgO—CaO, SiO ₂ —B ₂ O ₃ , SiO ₂ —CaO, SiO ₂ —MgO, SiO—BaO, or SiO—ZnO can be employed. In this specification, crystallized glass means that the ratio (crystallinity) of “volume occupied by crystal phase” to the total volume is 60% or more, and “volume occupied by amorphous phase and impurities relative to the total volume”. "Indicates a glass having a ratio of less than 40%. Note that amorphous glass or the like may be employed as the material of the first bonding material 5. Specifically, the second bonding material 101 is at least one selected from the group consisting of SiO ₂ —MgO—B ₂ O ₅ —Al ₂ O ₃ and SiO ₂ —MgO—Al ₂ O ₃ —ZnO. .

[Fuel cell stack]
Each fuel cell 10 is supported on the manifold 20 configured as described above. Specifically, the lower end portion of each fuel cell 10 is inserted into each insertion hole 411 of the lid member 4. The second bonding material 101 is filled in the insertion hole 411 in the state where the fuel cell 10 is inserted.

The second bonding material 101 is crystallized glass. As the crystallized glass, for example, a SiO ₂ —B ₂ O ₃ system, a SiO ₂ —CaO system, or a SiO ₂ —MgO system may be employed. Note that amorphous glass, brazing material, ceramics, or the like may be employed as the material of the second bonding material 101. Specifically, the second bonding material 101 is at least one selected from the group consisting of SiO ₂ —MgO—B ₂ O ₅ —Al ₂ O ₃ and SiO ₂ —MgO—Al ₂ O ₃ —ZnO. .

The fuel cell stack 100 configured as described above generates power as follows. A fuel gas (hydrogen gas or the like) is supplied into each gas flow path 121 of each fuel battery cell 10 via the manifold 20, and both surfaces of the support substrate 12 are exposed to a gas (air or the like) containing oxygen, thereby providing an electrolyte. An electromotive force is generated by a difference in oxygen partial pressure generated between the both side surfaces of 14. When this fuel cell stack 100 is connected to an external load, an electrochemical reaction shown in the following formula (1) occurs in the air electrode 15, an electrochemical reaction shown in the following formula (2) occurs in the fuel electrode 13, and a current flows. .
(1/2) · O ₂ + 2e ⁻ → O ₂ ⁻ (1)
H ₂ + O ₂ ⁻ → H ₂ O + 2e ⁻ (2)

[Modification]
As mentioned above, although embodiment of this invention was described, this invention is not limited to these, A various change is possible unless it deviates from the meaning of this invention.

Modification 1
In the above embodiment, the lid member 4 has the lid body portion 41 and the insertion portion 42, but the configuration of the lid member 4 is not particularly limited to this. For example, as shown in FIG. 8, the lid member 4 may not have the insertion portion 42.

Modification 2
In the said embodiment, although the cover member 4 has the some insertion hole 411, it is not limited to this. For example, as shown in FIG. 9, the lid member 4 of the manifold body 3 may have one insertion hole 411. And the lower end part of the some fuel cell 10 may be inserted in the one insertion hole 411. FIG.

  The present invention will be described more specifically with reference to the following examples and comparative examples. In addition, this invention is not limited to the following Example.

(Example)
Manifolds according to Examples 1 to 35 were produced as follows.

  First, as shown in FIG. 10, manifolds 20 having the same configuration as that of the above embodiment were produced as Examples 1 to 35. Specifically, the manifold body 3 is prepared, and the first bonding material 5 is filled in the groove 33. And after inserting the insertion part 42 of the cover member 4 in the groove part 33 of the manifold main body 3, it heat-processes for 120 minutes at 850 degreeC. The lid member 4 does not have the insertion hole 411. That is, the inside of the manifold 20 is a sealed space.

  In each embodiment, the materials of the first bonding material 5, the manifold body 3, and the lid member 4 are as shown in Table 1. Moreover, the curvature radius of the groove part 33 of the manifold in Examples 1-35 is as showing in Table 1. In addition, in the manifold 20 in Examples 1-35, it was set as the mutually same structure except the curvature radius of the groove part 33, and the material of the 1st joining material 5, the manifold main body 3, and the cover member 4. FIG.

(Comparative example)
As shown in FIG. 11, in the manifold 20 according to Comparative Examples 1 to 7, the cross-sectional shape of the groove 33 is a rectangular shape. The depth of the groove 33 is 5 mm and the width is 5 mm. In addition, the materials of the first bonding material 5, the manifold body 3, and the lid member 4 in each comparative example are as shown in Table 1. Other configurations are the same as those of the first to third embodiments.

(Evaluation method)
The presence or absence of the occurrence of gas leak was confirmed for the manifolds 20 according to Examples 1 to 35 and Comparative Examples 1 to 7 manufactured as described above. First, pressurized gas was introduced into the manifold 20 according to each example and comparative example via the introduction pipe 201. Next, the pressure in the manifold 20 was measured with a pressure gauge. Specifically, the applied pressure was 10 kPa, and the amount of gas leak (cc / min) at that time was measured. The evaluation results are shown in Table 1. In Table 1, the case of less than 0.1 cc / min (less than the lower limit of detection) is evaluated as “」 ”, and the case of 0.1 cc / min or more and less than 5 cc / min is evaluated as“ ◯ ”. The case of / min or more was evaluated as “×”.

  As shown in Table 1, in Comparative Examples 1 to 7, the evaluation was “x”. On the other hand, in Examples 1 to 35, the evaluation was “◎” or “◯”, and the evaluation was not “x”. As described above, in Examples 1 to 35, the evaluation was not “x”, but in Comparative Examples 1 to 7, the evaluation was “x” because of the difference in the cross-sectional shape of the groove 33. it is conceivable that. That is, when the first bonding material 5 is filled in the groove 33 and heat treatment is performed, the first bonding material 5 has a property of being rounded by the influence of surface tension. For this reason, as in Comparative Examples 1 to 7, the first bonding material 5 filled in the groove 33 having a rectangular cross-sectional shape has a gap formed at the corner of the groove 33 and is not sufficiently bonded. On the other hand, when the cross-sectional shape of the groove 33 is an arc shape as in Examples 1 to 35, the first bonding material 5 after the heat treatment has a shape that follows the shape of the groove 33 and no gap is formed. . As a result, Examples 1 to 35 are considered to have higher bonding strength and higher gas sealing performance than Comparative Examples 1 to 7.

  Further, in the manifold 20 according to Examples 2 to 4, 7 to 9, 12 to 14, 17 to 19, 22 to 24, 27 to 29, and 32 to 34 in which the curvature radius of the groove portion 33 is 1.0 to 10 mm, It was found that the gas tightness was higher. This is considered to be because the first bonding material 5 after the heat treatment has a shape along the groove portion 33 having a curvature radius of 1.0 to 10 mm.

3: Manifold body 31: Bottom wall 32: Side wall 321: Side wall body part 322: Flange part 33: Groove part 4: Lid member 41: Lid body part 411: Insert hole 42: Insert part 5: First bonding material 10: Fuel cell Cell 20: Manifold 100: Fuel cell stack

Claims (7)

A manifold for supplying gas to the fuel cell,
A manifold body having a bottom wall, a side wall extending upward from a peripheral edge of the bottom wall, and a groove portion extending from an upper surface of the side wall;
A lid member that has an insertion hole into which a lower end portion of the fuel battery cell is inserted, and closes an upper surface of the manifold body;
A first bonding material made of a glass material that fills the groove and bonds the manifold body and the lid member;
With
The groove part has an arc shape in a cross section perpendicular to the extending direction of the groove part.
Manifold. The radius of curvature of the groove is 1.0 to 10 mm.
The manifold according to claim 1. The side wall has a side wall main body part and a flange part extending outward from the side wall main body part,
The groove extends on the upper surface of the flange.
The manifold according to claim 1 or 2. The lid member includes a lid main body portion that closes an upper surface of the manifold main body, and an insertion portion that extends from a peripheral edge of the lid main body portion toward the groove portion.
The manifold according to any one of claims 1 to 3. The groove is annular.
The manifold according to any one of claims 1 to 4. The first bonding material is crystallized glass.
The manifold according to any one of claims 1 to 5. A manifold according to any of claims 1 to 6;
A fuel battery cell extending upward from the lid member of the manifold;
A fuel cell stack comprising:

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