JP6752386B1 - Electrochemical cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrochemical cell capable of improving electrical connectivity between an alloy member and an element portion. SOLUTION: A cell 1 includes an alloy member 4 and an element portion 10 arranged on the alloy member 4. The element portion 10 has a first electrode layer 5 supported by the alloy member 4, an electrolyte layer 7, and a second electrode layer 9. The alloy member 4 has a base material 41 made of an alloy material containing chromium, and a chromium oxide film 42 that covers at least a part of the base material 41. The chromium oxide film 42 contains a first portion 42a formed on the first main surface Sa of the base material 41. The first portion 42a is inserted between at least the first electrode layer 51 and the base material 41 of the element part 10, and is not inserted between the element part 10 and the base material 41. Includes insert a2. The thickness THa1 of the insertion portion a1 is thinner than the thickness THa2 of the non-insertion portion a2. [Selection diagram] Fig. 2

Description

The present invention relates to an electrochemical cell.

Conventionally, an electrochemical cell including an alloy member and an element portion arranged on the alloy member is known (see, for example, Patent Document 1). The alloy member described in Patent Document 1 has a base material made of an alloy material containing Cr (chromium) and a chromium oxide film covering the surface of the base material.

International Publication No. 2018/181926

The chromium oxide film not only has a function of suppressing the volatilization of Cr from the base material, but also has a function of improving the strength of the alloy member. Therefore, in order to suppress the volatilization of Cr and improve the strength of the alloy member, it is preferable to make the chromium oxide film thicker. However, if the chromium oxide film is thickened, the electrical connectivity between the alloy member and the element portion becomes low. It ends up.

An object of the present invention is to provide an electrochemical cell capable of improving the electrical connectivity between an alloy member and an element portion.

The electrochemical cell according to the present invention includes an alloy member and an element portion arranged on the alloy member. The element portion has a first electrode layer supported by an alloy member, a second electrode layer, and an electrolyte layer arranged between the first electrode layer and the second electrode layer. The alloy member has a base material made of an alloy material containing chromium and a chromium oxide film covering at least a part of the base material. The chromium oxide film contains a first portion formed on the first main surface of the substrate. The first portion includes at least an intervening portion inserted between the first electrode layer and the base material and a non-interposing portion not inserted between the element portion and the base material. The thickness of the inserted portion is thinner than the thickness of the non-interinserted portion.

According to the present invention, it is possible to provide an electrochemical cell capable of improving the electrical connectivity between the alloy member and the element portion.

Sectional drawing which shows the structure of the fuel cell which concerns on embodiment Enlarged view of region Xa in FIG. Sectional drawing which shows the structure of the fuel cell which concerns on other embodiment Partially enlarged view of FIG.

(Structure of fuel cell 1)
The fuel cell 1 is an example of the "electrochemical cell" according to the present invention. The "electrochemical cell" is a concept that includes not only a fuel cell but also an electrolytic cell for producing hydrogen and oxygen from water vapor. In the following description, the fuel cell is abbreviated as "cell".

FIG. 1 is a cross-sectional view showing the configuration of the cell 1 according to the embodiment. The cell 1 has a flow path member 3, an alloy member 4, a first electrode layer 5, an intermediate layer 6, an electrolyte layer 7, a reaction prevention layer 8, and a second electrode layer 9. In the present embodiment, the first electrode layer 5, the intermediate layer 6, the electrolyte layer 7, the reaction prevention layer 8, and the second electrode layer 9 constitute an "element unit 10" arranged on the surface 4S of the alloy member 4. To do.

[Flow path member 3]
The flow path member 3 is formed in a U shape. The flow path member 3 is joined to the back surface 4T of the alloy member 4. A flow path 3S is formed between the flow path member 3 and the alloy member 4. The flow path 3S is connected to a manifold (not shown). In the present embodiment, fuel gas (for example, hydrogen gas) is supplied from the manifold to the flow path 3S.

The flow path member 3 can be made of, for example, an alloy material. The flow path member 3 may have the same structure as the alloy member 4.

[Alloy member 4]
The alloy member 4 is a support that supports the first electrode layer 5, the intermediate layer 6, the electrolyte layer 7, the reaction prevention layer 8, and the second electrode layer 9. In the present embodiment, the alloy member 4 is formed in a plate shape, but the present invention is not limited to this. The alloy member 4 may have other shapes such as a tubular shape or a box shape.

A plurality of through holes 4p are formed in the region of the alloy member 4 to be joined to the first electrode layer 5. The fuel gas flowing through the flow path 3S is supplied to the first electrode layer 5 through the through holes 4p. Each through hole 4p can be formed by machining (for example, punching), laser processing, or chemical processing (for example, etching). Alternatively, the alloy member 4 may be made of a porous metal having gas permeability. In this case, since the holes formed in the porous metal function as the through holes 4p, it is not necessary to perform processing for forming the through holes 4p.

The alloy member 4 is formed in a plate shape. The alloy member 4 may have a flat plate shape or a curved plate shape. The thickness of the alloy member 4 is not particularly limited as long as the strength of the cell 1 can be maintained, but can be, for example, 0.1 mm to 2.0 mm. The detailed configuration of the alloy member 4 will be described later.

[First electrode layer 5]
The first electrode layer 5 is supported by the alloy member 4. The first electrode layer 5 is arranged on the alloy member 4 side of the electrolyte layer 7. The first electrode layer 5 is provided on the surface 4S of the alloy member 4. The first electrode layer 5 is provided so as to cover a region of the alloy member 4 in which a plurality of through holes 4p are provided. In FIG. 1, the first electrode layer 5 is arranged on the surface of the alloy member 4 and does not enter each through hole 4p, but at least a part of the first electrode layer 5 enters each through hole 4p. You may be.

The first electrode layer 5 is preferably porous. The porosity of the first electrode layer 5 is not particularly limited, but can be, for example, 20% to 70%. The thickness of the first electrode layer 5 is not particularly limited, but may be, for example, 1 μm to 100 μm.

In the present embodiment, a fuel gas (for example, hydrogen gas) is supplied to the first electrode layer 5, and the first electrode layer 5 functions as an anode (fuel electrode). The first electrode layer 5 is composed of a composite material such as NiO-GDC (gadolinium-doped ceria), Ni-GDC, NiO-YSZ (yttria-stabilized zirconia), Ni-YSZ, CuO-CeO ₂ , and Cu-CeO _2. can do.

The method for forming the first electrode layer 5 is not particularly limited, and is a firing method, a spray coating method (spattering method, aerosol deposition method, aerosol gas deposition method, powder jet deposit method, particle jet deposition method, cold spray method). Etc.), PVD method (sputtering method, pulse laser deposition method, etc.), CVD method, etc.

[Middle layer 6]
The intermediate layer 6 is arranged on the first electrode layer 5. The intermediate layer 6 is interposed between the first electrode layer 5 and the electrolyte layer 7. The thickness of the intermediate layer 6 is not particularly limited, but can be, for example, 1 μm to 100 μm.

The intermediate layer 6 preferably has oxide ion (oxygen ion) conductivity. It is more preferable that the intermediate layer 6 has electron conductivity. The intermediate layer 6 can be composed of YSZ, GDC, SSZ (scandium-stabilized zirconia), SDC (samarium-doped ceria), or the like. The method for forming the intermediate layer 6 is not particularly limited, and the intermediate layer 6 can be formed by a firing method, a spray coating method, a PVD method, a CVD method, or the like.

[Electrolyte layer 7]
The electrolyte layer 7 is arranged between the first electrode layer 5 and the second electrode layer 9. In the present embodiment, since the cell 1 has the intermediate layer 6 and the reaction prevention layer 8, the electrolyte layer 7 is interposed between the intermediate layer 6 and the reaction prevention layer 8.

In the present embodiment, the electrolyte layer 7 is formed so as to cover the entire first electrode layer 5, and the outer edge of the electrolyte layer 7 is joined to the alloy member 4. As a result, mixing of the fuel gas supplied to the first electrode layer 5 and the oxidant gas supplied to the second electrode layer 9 can be suppressed, so that the alloy member 4 and the electrolyte layer 7 are separately sealed. There is no need.

The electrolyte layer 7 has oxide ion conductivity. The electrolyte layer 7 has a gas barrier property that can suppress the mixing of the oxidant gas and the fuel gas. The electrolyte layer 7 may have a multi-layer structure, but it is preferable that at least one layer is a dense layer. The porosity of the dense layer is preferably 10% or less, more preferably 5% or less, still more preferably 2% or less. The thickness of the electrolyte layer 7 is not particularly limited, but can be, for example, 1 μm to 10 μm.

The electrolyte layer 7 can be composed of YSZ, GDC, SSZ, SDC, LSGM and the like. The method for forming the electrolyte layer 7 is not particularly limited, and the electrolyte layer 7 can be formed by a firing method, a spray coating method, a PVD method, a CVD method, or the like.

[Reaction prevention layer 8]
The reaction prevention layer 8 is arranged on the electrolyte layer 7. The reaction prevention layer 8 is interposed between the electrolyte layer 7 and the second electrode layer 9. The thickness of the reaction prevention layer 8 is not particularly limited, but can be, for example, 1 μm to 100 μm. The reaction prevention layer 8 suppresses the reaction between the constituent material of the second electrode layer 9 and the constituent material of the electrolyte layer 7 to form a high resistance layer.

The reaction prevention layer 8 can be made of a ceria-based material such as GDC or SDC. The method for forming the reaction prevention layer 8 is not particularly limited, and the reaction prevention layer 8 can be formed by a firing method, a spray coating method, a PVD method, a CVD method, or the like.

[Second electrode layer 9]
The second electrode layer 9 is arranged on the opposite side of the first electrode layer 5 with reference to the electrolyte layer 7. In the present embodiment, since the cell 1 has the reaction prevention layer 8, the second electrode layer 9 is arranged on the reaction prevention layer 8.

The second electrode layer 9 is preferably porous. The porosity of the second electrode layer 9 is not particularly limited, but can be, for example, 20% to 70%. The thickness of the second electrode layer 9 is not particularly limited, but can be, for example, 1 μm to 100 μm.

In the present embodiment, an oxidizing agent gas (for example, air) is supplied to the second electrode layer 9, and the second electrode layer 9 functions as a cathode (air electrode). The second electrode layer 9 can be composed of LSCF, LSF, LSC, LNF, LSM and the like. In particular, the second electrode layer 9 preferably contains a perovskite-type oxide containing two or more kinds of elements selected from the group consisting of La, Sr, Sm, Mn, Co and Fe.

The method for forming the second electrode layer 9 is not particularly limited, and the second electrode layer 9 can be formed by a firing method, a spray coating method, a PVD method, a CVD method, or the like. The method for forming the second electrode layer 9 is not particularly limited, and the second electrode layer 9 can be formed by a firing method, a spray coating method, a PVD method, a CVD method, or the like.

[Operation of cell 1]
First, while supplying fuel gas from the flow path 3S to the first electrode layer 5 through the through holes 4p and supplying the oxidant gas to the second electrode layer 9, the cell 1 is operated at an operating temperature (for example, 600). (° C. to 850 ° C.). Then, in the second electrode layer 9, O ₂ (oxygen) reacts with e ⁻ (electrons) to generate O ^2- (oxygen ions). The generated O ^2- moves to the first electrode layer 5 through the electrolyte layer 7. O ^{2- that} has moved to the first electrode layer 5 reacts with H ₂ (hydrogen) contained in the fuel gas to generate H ₂ O (water) and e ⁻ . By such a reaction, an electromotive force is generated between the first electrode layer 5 and the second electrode layer 9.

(Detailed configuration of alloy member 4)
FIG. 2 is an enlarged cross-sectional view showing the region Xa shown in FIG.

As shown in FIG. 2, the alloy member 4 has a base material 41 and a chromium oxide film 42.

The base material 41 is made of an alloy material containing Cr (chromium). As such a metal material, Fe—Cr based alloy steel (stainless steel or the like), Ni—Cr based alloy steel, or the like can be used. The content of Cr in the base material 41 is not particularly limited, but may be 4 to 30% by mass.

The base material 41 may contain Ti (titanium) or Al (aluminum). The content of Ti in the base material 41 is not particularly limited, but 0.01 to 1.0 at. Can be%. The content of Al in the base material 41 is not particularly limited, but 0.01 to 0.4 at. Can be%. The base material 41 may contain Ti as TiO ₂ (titania) or Al as Al ₂ O ₃ (alumina).

The base material 41 has a first main surface Sa, a second main surface Sb, an outer peripheral surface Sc, and an inner peripheral surface Sd of each through hole 4p. The first main surface Sa, the second main surface Sb, the outer peripheral surface Sc, and the inner peripheral surface Sd are the surfaces of the base material 41. The first main surface Sa, the second main surface Sb, and the outer peripheral surface Sc are the outer surface of the base material 41, and the inner peripheral surface Sd is the inner surface of the base material 41.

The first main surface Sa of the base material 41 is provided on the surface 4S side of the alloy member 4. The second main surface Sb of the base material 41 is provided on the back surface 4T side of the alloy member 4. The second main surface Sb of the base material 41 is provided on the opposite side of the first main surface Sa of the base material 41. The outer peripheral surface Sc is connected to the outer edges of the first main surface Sa and the second main surface Sb, respectively. The outer peripheral surface Sc is formed in an annular shape. Each inner peripheral surface Sd is connected to each of the first main surface Sa and the second main surface Sb. Each inner peripheral surface Sd is formed in a tubular shape.

The chromium oxide film 42 is formed on the base material 41. The chromium oxide film 42 covers at least a part of the base material 41. The chromium oxide film 42 may cover at least a part of the base material 41, but may cover the entire base material 41.

The chromium oxide film 42 contains chromium oxide as a main component. In the present embodiment, the phrase "the composition X contains the substance Y as a main component" means that the substance Y accounts for 70% by weight or more of the entire composition X.

The chromium oxide film 42 has a function of suppressing the volatilization of Cr from the base material 41 and a function of improving the strength of the alloy member 4.

In the present embodiment, the chromium oxide film 42 has a first portion 42a, a second portion 42b, a third portion 42c, and a plurality of fourth portions 42d. The first portion 42a is formed on the first main surface Sa of the base material 41. The second portion 42b is formed on the second main surface Sb of the base material 41. The third portion 42c is formed on the outer peripheral surface Sc of the base material 41. Each fourth portion 42d is formed on each inner peripheral surface Sd of the base material 41. The first to fourth portions 42a to 42d may be integrally connected to each other.

The first portion 42a of the chromium oxide film 42 includes an interstitial portion a1 and a non-interstitial portion a2.

The insertion portion a1 is inserted between the element portion 10 and the base material 41. The insertion portion a1 is covered with at least the first electrode layer 5 of the element portion 10. The insertion portion a1 is electrically and mechanically connected to at least the first electrode layer 5 of the element portion 10. In the present embodiment, the insertion portion a1 is interposed between the first electrode layer 5, the intermediate layer 6, and the electrolyte layer 7 of the element portion 10 and the base material 41, but at least the first electrode. It may be inserted between the layer 5 and the base material 41.

The non-insertion portion a2 is not inserted between the base material 41 and the element portion 10. The non-interlaced portion a2 is exposed from the element portion 10. However, in the present embodiment, the non-insertion portion a2 is in contact with the electrolyte layer 7 of the element portion 10 at a step (inner side surface) with the insertion portion a1.

The thickness THa1 of the insertion portion a1 is thinner than the thickness THa2 of the non-insertion portion a2. By reducing the thickness THa1 of the insertion portion a1 in this way, the electrical connectivity between the element portion 10 (particularly, the first electrode layer 5) and the alloy member 4 can be improved. Further, since the thickness THa2 of the non-interlaced portion a2 can be increased, it is possible to suppress the volatilization of Cr and secure the strength of the alloy member 4 at the same time.

The thickness THa1 of the insertion portion a1 is the first portion 42a of the chromium oxide film 42 when the cross section perpendicular to the surface 4S of the alloy member 4 is observed using an FE-SEM (field emission scanning electron microscope). Of these, it is obtained by measuring the maximum thickness of the portion inserted between the first electrode layer 5 and the base material 41.

The thickness THa1 of the insertion portion a1 is not particularly limited, but is preferably 0.1 μm or more and 7 μm or less. As a result, the flexibility of the portion of the alloy member 4 in contact with the element portion 10 can be ensured, so that it is possible to suppress the occurrence of peeling between the alloy member 4 and the element portion 10 due to thermal stress. The thickness THa1 of the insertion portion a1 is preferably 7 μm or less, more preferably 5 μm or less, and particularly preferably 3 μm or less.

The thickness THa2 of the non-interlaced portion a2 is the element portion 10 and the base material of the first portion 42a of the chromium oxide film 42 when the cross section perpendicular to the surface 4S of the alloy member 4 is observed using FE-SEM. It is obtained by measuring the maximum thickness of the portion that is not inserted between the 41 and the 41.

The thickness THa2 of the non-insertion portion a2 is not particularly limited, but is preferably 0.2 μm or more and 10 μm or less. As a result, the strength of the outer peripheral portion of the alloy member 4 can be ensured, so that it is possible to prevent the alloy member 4 from being separated from the element portion 10 due to the deformation of the alloy member 4. The thickness THa2 of the non-inserted portion a2 is preferably 0.2 μm or more, more preferably 0.3 μm or more, and particularly preferably 0.4 μm or more.

Here, the ratio (THa1 / THa2) of the thickness THa1 of the insertion portion a1 to the thickness THa2 of the non-insertion portion a2 is preferably 0.1 or more and 0.93 or less. As a result, the balance between the flexibility and the strength of the alloy member 4 can be improved, so that the occurrence of peeling between the alloy member 4 and the element portion 10 can be efficiently suppressed.

The thickness THb of the second portion 42b may be thicker than the thickness THa2 of the non-insertion portion a2, but is preferably thinner than the thickness THa2 of the non-intersection portion a2. As a result, it is possible to impart appropriate strength to the alloy member 4 and improve the stress relaxation function of the alloy member 4. Specifically, first, by providing the second portion 42b, it is possible to prevent the alloy member 4 from being excessively deformed. Therefore, the through hole 4p of the alloy member 4 may be closed, or the joint portion between the cell 1 and another member (for example, a separator or a current collector member not shown) connected to the cell 1 may be peeled off. Can be suppressed. Further, by making the thickness THb of the second portion 42b thinner than the thickness TH2 of the non-interlaced portion a2, it is possible to prevent the entire alloy member 4 from becoming excessively hard and secure the deformability. Therefore, since it is possible to suppress the generation of thermal stress inside the element portion 10 when the temperature is raised and lowered, it is possible to suppress the occurrence of peeling and cracking in the element portion 10. The thickness THb of the second portion 42b is not particularly limited, but can be, for example, 0.1 μm or more and 7 μm or less. The thickness THb of the second portion 42b is preferably 7 μm or less, more preferably 5 μm or less, and particularly preferably 3 μm or less.

The thickness THc of the third portion 42c may be thicker than the thickness THa2 of the non-insertion portion a2, but is preferably thinner than the thickness THa2 of the non-intersection portion a2. As a result, it is possible to impart appropriate strength to the alloy member 4 and improve the stress relaxation function of the alloy member 4. The thickness THc of the third portion 42c is not particularly limited, but can be, for example, 0.1 μm or more and 7 μm or less. The thickness THc of the third portion 42c is preferably 7 μm or less, more preferably 5 μm or less, and particularly preferably 3 μm or less.

The thickness THd of the fourth portion 42d may be thicker than the thickness THa2 of the non-insertion portion a2, but is preferably thinner than the thickness THa2 of the non-intersection portion a2. As a result, it is possible to impart appropriate strength to the alloy member 4 and improve the stress relaxation function of the alloy member 4. The thickness THd of the fourth portion 42d is not particularly limited, but can be, for example, 0.1 μm or more and 7 μm or less. The thickness THd of the fourth portion 42d is preferably 7 μm or less, more preferably 5 μm or less, and particularly preferably 3 μm or less.

(Method for manufacturing alloy member 4)
In order to produce the alloy member 4, various methods such as a chrome plating method, a PVD method, and a chrome oxide paste coating can be used.

For example, a method for producing the alloy member 4 using the chrome plating method is as follows.

First, a region of the surface of the base material 41 other than the region forming the non-interfering portion a2 (that is, a region of the first main surface Sa on which the interposing portion a1 is formed, the second main surface Sb, the outer peripheral surface Sc, And the inner peripheral surface Sd) is masked.

Next, a chrome plating film is formed on the region of the surface of the base material 41 on which the non-insertion portion a2 is formed by performing a chrome plating treatment on the region of the base material 41 on which the non-intertrusion portion a2 is formed.

Next, the masking applied to the surface of the base material 41 is removed.

Next, by performing a chrome plating treatment on the entire surface of the base material 41, a chrome plating film is formed on the surface of the base material 41 other than the region where the non-insertion portion a2 is formed, and the non-intertrusion portion is formed. The chrome-plated film formed in the region where a2 is formed is thickened.

Next, the base material 41 on which the chromium plating film is formed is heat-treated in an air atmosphere (for example, 550 ° C. to 850 ° C., 3 hours to 100 hours) to complete the base material 41 coated with the chromium oxide film 42. To do.

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

In the above embodiment, the alloy member 4 has the base material 41 and the chromium oxide film 42, but may have a coating film formed on the chromium oxide film 42. As the material constituting the coating film, a ceramic material, a metal material, or the like can be used. As the ceramic material, for example, a perovskite-type composite oxide containing La and Sr, a spinel-type composite oxide composed of transition metals such as Mn, Co, Ni, Fe, and Cu, and a glass material can be used. .. As the metal material, Ni, Co, Fe, Cu and the like can be used. Since conductivity is not required in the region of the surface of the alloy member 4 where the flow path member 3 and the first electrode layer 5 are not connected to each other, the region is covered with a coating film made of an insulating material. It may have been done.

In the above embodiment, the element unit 10 includes the intermediate layer 6 and the reaction prevention layer 8, but does not have to include at least one of the intermediate layer 6 and the reaction prevention layer 8.

In the above embodiment, the first electrode layer 5 functions as an anode and the second electrode layer 9 functions as a cathode, but the first electrode layer 5 functions as a cathode and the second electrode layer 9 functions as an anode. It may work. In this case, the constituent materials of the first electrode layer 5 and the second electrode layer 9 may be exchanged, the fuel gas may flow through the outer surface of the first electrode layer 5, and the oxidant gas may flow through the flow path 3S.

In the above embodiment, the insertion portion a1 of the first portion 42a of the chromium oxide film 42 is located between the first electrode layer 5, the intermediate layer 6, and the electrolyte layer 7 of the element portion 10 and the base material 41. Although it is decided to be inserted, it is sufficient that it is inserted at least between the first electrode layer 5 and the base material 41. For example, when the element portion 10 does not include the intermediate layer 6, the interposition portion a1 is intervened between the first electrode layer 5 and the electrolyte layer 7 of the element portion 10 and the base material 41. Further, when the intermediate layer 6 and the electrolyte layer 7 do not come into contact with the alloy member 4, the interposition portion a1 is intervened between only the first electrode layer 5 of the element portion 10 and the base material 41. However, it is preferable that the insertion portion a1 is inserted not only between the first electrode layer 5 and the base material 41 but also between the electrolyte layer 7 and the base material 41. As a result, the electrical connectivity between the element portion 10 and the alloy member 4 can be further improved.

In the above embodiment, the chromium oxide film 42 has a first portion 42a, a second portion 42b, a third portion 42c, and a plurality of fourth portions 42d, but may have at least the first portion 42a. It suffices to have at least one of the second portion 42b, the third portion 42c, and the plurality of fourth portions 42d.

In the above embodiment, the fuel cell 1 is not provided with a specific flow path for flowing the oxidant gas supplied to the second electrode layer 9, but as shown in FIG. 3, the oxidant gas is used. A flow path member 20 that forms the flow path 20S may be provided. The flow path member 20 is joined to the surface 4S of the alloy member 4 via a joining material 21 such as a glass material. In this case, as shown in FIG. 4, the non-interlaced portion a2 of the first portion 42a of the chromium oxide film 42 included in the alloy member 4 is thinned in the bonding region a3 to which the bonding material 21 is bonded. preferable. Thereby, the bonding strength at the bonding interface can be improved. The thickness THa3 of the joint region a3 is not particularly limited, but can be, for example, 0.1 μm or more and 7 μm or less. Even when the non-interstitial portion a2 is partially thinned in this way, the thickness THa2 of the non-interstitial portion a2 is such that the element portion 10 and the base material 41 of the first portion 42a are formed. This is the maximum thickness of the part that is not inserted between them.

Hereinafter, examples of the present invention will be described. In this embodiment, the influence of the ratio (THa1 / THa2) of the thickness THa1 of the insertion portion a1 to the thickness THa2 of the non-insertion portion a2 on the separation between the alloy member 4 and the element portion 10 is verified.
(Examples 1 to 13 and Comparative Examples 1 to 3)
The fuel cell 1 according to Examples 1 to 13 and Comparative Examples 1 to 3 was produced as follows.
First, a stainless steel base material 41 having a thickness of 0.5 mm was prepared, and masking was performed on the surface of the base material 41 other than the region where the non-insertion portion a2 was formed.

Next, a chrome plating film was formed by subjecting a chrome plating treatment to a region of the surface of the base material 41 on which the non-insertion portion a2 was formed. At this time, as shown in Table 1, the thickness THa2 of the non-insertion portion a2 was adjusted by adjusting the chrome plating treatment time.

Next, after removing the masking applied to the surface of the base material 41, the entire surface of the base material 41 is subjected to a chrome plating treatment to form a chrome plating film other than the region where the non-interlaced portion a2 is formed. , The chrome-plated film formed in the region forming the non-interlaced portion a2 was thickened. At this time, by adjusting the chrome plating treatment time, as shown in Table 1, the thickness THa1 of the insertion portion a1 and the thickness THa2 of the non-insertion portion a2 were adjusted.

Next, the alloy member 4 was completed by heat-treating the base material 41 on which the chromium-plated film was formed in an air atmosphere (550 ° C., 1 hour).

Next, the fuel cell 1 having the configuration shown in FIG. 1 is prepared, and the fuel cell 1 is bonded to the insertion portion a1 of the alloy member 4 by using Ni paste as the conductive bonding material to create a nitrogen atmosphere. It was sintered by firing at 800 ° C. for 1 hour. As described above, the fuel cell 1 according to Examples 1 to 13 and Comparative Examples 1 to 3 was completed.

(Thermodynamic cycle test)
A step of putting the fuel cell 1 according to Examples 1 to 13 and Comparative Examples 1 to 3 into a heating furnace and raising the temperature from room temperature to 550 ° C. at a heating rate of 200 ° C./h, and a step of raising the temperature from 550 ° C. to room temperature with a temperature lowering rate of 200. The step of lowering the temperature at ° C./h was repeated 50 times.

Next, an ultrasonic flaw detection test and a cross-sectional observation of the fuel cell 1 were carried out using an ultrasonic flaw detector (manufactured by Hitachi Power Solutions, model FineSAT FS100III), and peeling between the alloy member 4 and the element portion 10 was performed. Was confirmed. Specifically, the reflected echo at the depth position near the interface between the alloy member 4 and the element portion 10 was imaged by the C scan method. Next, in the bright region of the C scan image, the cross section of the alloy member 4 along the thickness direction was observed by FE-SEM to confirm the presence or absence of peeling. The confirmation results are shown in Table 1. In Table 1, those in which no peeling was confirmed between the alloy member 4 and the element portion 10 were evaluated as 〇, and those in which peeling was confirmed between the alloy member 4 and the element portion 10 were evaluated as ×. ..

Next, the cross section of the alloy member 4 along the thickness direction was observed by FE-SEM, and the thickness THa1 of the interstitial portion a1 and the thickness THa2 of the non-interstitial portion a2 were measured.

As shown in Table 1, in Examples 1 to 13 in which the ratio (THa1 / THa2) of the thickness TH1 of the insertion portion a1 to the thickness THa2 of the non-insertion portion a2 was 0.1 or more and 0.93 or less, the alloy member. It was possible to suppress the occurrence of peeling between 4 and the element portion 10. Such a result was obtained because the balance between the flexibility and the strength of the alloy member 4 could be improved.

1 Cell 3 Flow path member 4 Alloy member 4S Front surface 4T Back surface 4p Through hole 41 Base material Sa 1st main surface Sb 2nd main surface Sc Outer surface Sd Inner peripheral surface 42 Chromium oxide film 42a 1st part a1 Insertion part a2 Non Insertion part 42b 2nd part 42c 3rd part 42d 4th part 5 1st electrode layer 6 Intermediate layer 7 Electrolyte layer 8 Reaction prevention layer 9 2nd electrode layer

Claims (5)

With alloy members
The element unit arranged on the alloy member and
With
The element part is
The first electrode layer supported by the alloy member and
The second electrode layer and
An electrolyte layer arranged between the first electrode layer and the second electrode layer,
Have,
The alloy member
A base material composed of an alloy material containing chromium and
A chromium oxide film covering at least a part of the base material and
Have,
The chromium oxide film comprises a first portion formed on a first main surface of the substrate.
The first portion is an interposition portion that is interposed between at least the first electrode layer and the base material of the element portion, and a non-interposition portion that is not intervened between the element portion and the base material. Including part
The thickness of the insertion portion is thinner than the thickness of the non-intertrusion portion.
Electrochemical cell. The interposition portion is intervened between the first electrode layer and the electrolyte layer of the element portion and the base material.
The electrochemical cell according to claim 1. The alloy member has a coating film that covers at least a part of the surface of the chromium oxide film.
The electrochemical cell according to claim 1 or 2. The chromium oxide film comprises a second portion formed on the second main surface of the substrate.
The thickness of the second portion is thinner than the thickness of the non-inserted portion.
The electrochemical cell according to any one of claims 1 to 3. The ratio of the thickness of the inserted portion to the thickness of the non-inserted portion is 0.1 or more and 0.93 or less.
The electrochemical cell according to any one of claims 1 to 4.

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