JP2020107592A - Electrochemical cell stack - Google Patents

Abstract

To provide an electrochemical cell stack capable of restraining a leakage current.SOLUTION: In a cell stack consisting of a fuel battery cell 100, a manifold for supporting the fuel battery cell 100, and a glass seal part 300 therebetween, the manifold has a manifold closest contact P1 closest to a first intersection point Q1 on the power generation element part A side, out of two intersection points Q1, Q2 of the fuel battery cell 100 and the glass seal part 300, in a profile perpendicular to the surface of the fuel battery cell 100, and the fuel battery cell 100 has a cell closet contact R1 closest to the manifold closest contact P1 of the manifold. The glass seal part 300 has a first region 300a within 100 μm along the surface of the fuel battery cell 100 around the cell closet contact R1, and within 20 μm in the vertical direction from the surface of the fuel battery cell 100. Porosity of the first region 300a is 5% or more.SELECTED DRAWING: Figure 5

Description

The present invention relates to electrochemical cell stacks.

Conventionally, an electrochemical cell stack includes an electrochemical cell, a manifold made of metal, and a glass seal part made of crystallized glass (see Patent Document 1).

In Patent Document 1, a fuel cell, which is a type of electrochemical cell, is used. The manifold supports the proximal end of the electrochemical cell. The glass seal portion joins the fuel cell and the manifold. The glass seal portion divides an internal space (for example, a space to which the fuel gas is supplied) and an external space (for example, a space to which the air is supplied) of the manifold to prevent mixing of the fuel gas and the air. ..

JP 2005-100687 A

However, during the operation of the electrochemical cell stack, a large electric field strength is generated in the narrow gap between the electrochemical cell and the manifold, so that a weak leak current may flow from the electrochemical cell to the manifold through the glass seal portion. is there.

The present invention is to provide an electrochemical cell stack capable of suppressing the leak current through the glass seal portion.

The electrochemical cell stack according to the present invention includes an electrochemical cell, a manifold, and a glass seal part. The electrochemical cell has a support substrate and a power generation element portion arranged on the support substrate. The manifold supports the proximal end of the electrochemical cell. The glass seal part is arranged between the electrochemical cell and the manifold. In a cross section perpendicular to the surface of the electrochemical cell, the manifold has a manifold closest contact point closest to the intersection on the power generation element side of the two intersections of the electrochemical cell and the glass seal portion. It has the cell closest contact closest to the manifold closest contact of the manifold. In the cross section, the glass seal part has a first region within 100 μm along the surface of the electrochemical cell centering on the cell closest contact point of the electrochemical cell and within 20 μm in the vertical direction from the surface of the electrochemical cell. The porosity of the first region is 5% or more.

ADVANTAGE OF THE INVENTION According to this invention, the electrochemical cell stack which can suppress the leak current through a glass seal part can be provided.

It is the whole cell stack perspective view concerning the embodiment of the present invention. It is the whole fuel cell perspective view. It is the whole manifold perspective view. It is a partial expanded sectional view of a fuel cell and a manifold. FIG. 5 is a partially enlarged view of FIG. 4.

<Structure of cell stack>
The configuration of the cell stack 1 according to this embodiment will be described with reference to the drawings. FIG. 1 is an overall perspective view of the cell stack 1. FIG. 2 is an overall perspective view of the manifold 200. FIG. 3 is an overall perspective view of the fuel cell 100. FIG. 4 is a partially enlarged cross-sectional view of the fuel cell 100 and the manifold 200. FIG. 4 shows a cross section perpendicular to the surface of the fuel cell 100. In addition, in FIGS. 1 to 4, an xyz coordinate system is set.

The cell stack 1 is an example of the "electrochemical cell stack" according to the present invention. The cell stack 1 includes a plurality of fuel cells 100, a manifold 200, and a glass seal part 300.

<Manifold>
The manifold 200 is a hollow body for supplying a fuel gas to each of the plurality of fuel cells 100. As shown in FIGS. 1 and 2, the manifold 200 has a substantially rectangular parallelepiped shape. The height direction, the lateral direction, and the longitudinal direction of the manifold 200 correspond to the x-axis direction, the y-axis direction, and the z-axis direction, respectively.

As shown in FIGS. 1 and 2, the manifold 200 has a base 210 and a support plate 220. The base 210 is made of a metal material (for example, stainless steel or the like). The base 210 has a bottom and a side wall surrounding the bottom. The bottom and the side wall form an opening that opens upward.

The support plate 220 is made of a metal material (for example, stainless steel). The support plate 220 is disposed on the base 210. Specifically, the support plate 220 is arranged at the tip of the side wall of the base 210 and closes the opening of the base 210. In this way, the support plate 220 closes the opening of the base 210 to form the internal space S1 in the manifold 200 (see FIG. 4). Fuel gas is introduced into the internal space S1.

The fuel gas is introduced into the internal space S1 from the outside through the introduction pipe 230. The introduction pipe 230 is made of a metal material (for example, stainless steel). The introduction pipe 230 is joined to the support plate 220 of the manifold 200.

The manifold 200 supports each fuel cell 100. Specifically, the support plate 220 of the manifold 200 has a plurality of through holes 221. Each through hole 221 is formed in the support plate 220 so as to connect the outside (external space) of the manifold 200 and the internal space S1. More specifically, each through hole 221 penetrates the support plate 220 in the x-axis direction (height direction). Each through hole 221 is formed at a predetermined interval in the z-axis direction (longitudinal direction), and is also formed at a predetermined interval in the y-axis direction (transverse direction).

<Fuel cell>
The fuel cell 100 is an example of the "electrochemical cell" according to the present invention. As shown in FIG. 1, each fuel cell unit 100 is erected on a manifold 200. The fuel cells 100 are arranged at intervals.

As shown in FIG. 3, the fuel cell 100 is formed in a substantially flat plate shape. The longitudinal direction, the lateral direction, and the thickness direction of the fuel cell 100 correspond to the x-axis direction, the y-axis direction, and the z-axis direction, respectively.

The length L1 of the fuel cell 100 in the x-axis direction is not particularly limited, but can be set within the range of 50 mm or more and 500 mm or less. The length L2 of the fuel cell 100 in the y-axis direction is not particularly limited, but can be set within the range of 10 mm or more and 100 mm or less. The length L3 of the fuel cell 100 in the z-axis direction is not particularly limited, but can be set within the range of 1 mm or more and 5 mm or less.

As shown in FIG. 4, the base end portion 10 a of the fuel cell 100 on the side into which the fuel gas flows in the x-axis direction (longitudinal direction) is joined to the manifold 200 by the glass seal portion 300. The tip portion 10b on the side where the fuel gas is discharged in the x-axis direction of the fuel cell unit 100 is a free end.

As shown in FIG. 3, each fuel cell unit 100 has a support substrate 10, a seal film 20, and a plurality of power generation element portions A.

The support substrate 10 is a fired body made of a porous material having no electronic conductivity. The support substrate 10 is made of, for example, CSZ (calcia-stabilized zirconia).

The support substrate 10 supports each power generating element unit A. Specifically, a plurality of power generation element portions A are provided on both main surfaces of the support substrate 10 at predetermined intervals in the x-axis direction.

A plurality of fuel gas channels 11 are formed inside the support substrate 10. Each fuel gas channel 11 extends in the x-axis direction. Each fuel gas channel 11 penetrates the support substrate 10. Each fuel gas channel 11 is formed at a predetermined interval in the y-axis direction (width direction).

The seal film 20 covers the entire outer surface of the support substrate 10 excluding the region where each power generating element portion A is arranged. The sealing film 20 is connected to the side surface of each power generating element portion A.

The sealing film 20 can be made of a dense material. Examples of the dense material include YSZ (yttria-stabilized zirconia), ScSZ (scandia-stabilized zirconia), crystallized glass, spinel oxide, MgO (magnesia), Al ₂ O ₃ (alumina), Y ₂ O ₃ ( Yttria) and the like. The thickness of the seal film 20 is not particularly limited, but may be, for example, about 3 to 50 μm. The porosity of the seal film 20 is not particularly limited, but is preferably less than 20%, more preferably 10% or less, further preferably 8% or less. The seal film 20 functions as a gas barrier layer together with the electrolyte layer 5, the reaction prevention layer 7, and the interconnector 31 described later.

The seal film 20 may be made of the same material as the electrolyte layer 5 described later. In this case, the seal film 20 may be formed integrally with the electrolyte layer 5.

Each power generation element section A is arranged on the support substrate 10. The power generating element units A are electrically connected in series. The number of power generation element units A is not particularly limited.

Here, FIG. 5 is an enlarged view of FIG. 4. In FIG. 5, a cross section parallel to the xy plane is shown. As shown in FIG. 5, each power generation element portion A has a fuel electrode 4, an electrolyte layer 5, an air electrode 6, and a reaction prevention layer 7.

The fuel electrode 4 has a fuel electrode current collecting layer 41 and a fuel electrode active layer 42.

The anode current collecting layer 41 is arranged in the first recess 22 formed in the support substrate 10. The fuel electrode current collecting layer 41 is made of a porous material having electronic conductivity. The anode current collecting layer 41 is formed of, for example, a composite material of NiO (nickel oxide) and YSZ (8YSZ) (yttria-stabilized zirconia), a composite material of NiO (nickel oxide) and Y ₂ O ₃ (yttria), and NiO (oxidation). It can be composed of a composite material of nickel) and CSZ (calcia-stabilized zirconia). The thickness of the fuel electrode current collecting layer 41 can be, for example, about 50 to 500 μm.

The anode active layer 42 is arranged in the second recess 41 a formed in the anode current collecting layer 41. The fuel electrode active layer 42 is made of a porous material having electronic conductivity. The anode active layer 42 can be made of, for example, a composite material of NiO (nickel oxide) and YSZ (yttria-stabilized zirconia), a composite material of NiO (nickel oxide) and GDC (gadolinium-doped ceria), and the like. The thickness of the anode active layer 42 may be, for example, 5 to 30 μm.

The electrolyte layer 5 is arranged on the fuel electrode 4. The electrolyte layer 5 extends in the longitudinal direction from one interconnector 31 to another interconnector 31. Therefore, the electrolyte layers 5 and the interconnectors 31 are alternately arranged in the longitudinal direction of the fuel cell 300. The electrolyte layer 5 and the interconnector 31 exhibit a gas barrier property that prevents the fuel gas on the support substrate 10 side and the air on the air electrode 6 side from being mixed. The outer edge of the electrolyte layer 5 is connected to the seal film 20.

The porosity of the electrolyte layer 5 is preferably less than 20%, more preferably 10% or less, further preferably 8% or less. The thickness of the electrolyte layer 5 can be, for example, about 3 to 50 μm.

The electrolyte layer 5 is composed of a dense material whose oxide ion conductivity is higher than electron conductivity. The electrolyte layer 5 can be made of, for example, YSZ (yttria-stabilized zirconia) or LSGM (lanthanum gallate).

The reaction prevention layer 7 is arranged between the electrolyte layer 5 and the air electrode 6. The reaction prevention layer 7 suppresses the reaction between YSZ in the electrolyte layer 5 and Sr in the air electrode 6 to form a reaction layer having a large electric resistance at the interface between the electrolyte layer 5 and the air electrode 6.

The reaction prevention layer 7 is made of a dense material. The reaction prevention layer 7 can be made of, for example, GDC=(Ce,Gd)O ₂ (gadolinium-doped ceria). The thickness of the reaction prevention layer 7 can be set to, for example, about 3 to 50 μm. The porosity of the reaction prevention layer 7 is preferably less than 20%, more preferably 10% or less, and further preferably 8% or less. The reaction prevention layer 7 exhibits a gas barrier property, like the electrolyte layer 5.

The air electrode 6 is arranged on the reaction prevention layer 7. The air electrode 6 is made of a porous material having electronic conductivity. The air electrode 6 includes, for example, LSCF=(La,Sr)(Co,Fe)O ₃ (lanthanum strontium cobalt ferrite), LSF=(La,Sr)FeO ₃ (lanthanum strontium ferrite), LNF=La(Ni,Fe). )O ₃ (lanthanum nickel ferrite), LSC=(La,Sr)CoO ₃ (lanthanum strontium cobaltite), and the like. The thickness of the air electrode 6 may be, for example, 10 to 100 μm.

The electrical connection section 30 electrically connects two adjacent power generation element sections A to each other. In the present embodiment, the electrical connection section 30 connects the adjacent power generation element sections A to each other in series, but may connect them in parallel. The electrical connection section 30 includes an interconnector 31 and an air electrode current collecting layer 32.

The interconnector 31 is arranged in the third recess 41b formed in the fuel electrode current collecting layer 41. The interconnector 31 is made of a dense material having electronic conductivity. The interconnector 31 can be made of, for example, LaCrO ₃ (lanthanum chromite) or (Sr,La)TiO ₃ (strontium titanate). The porosity of the interconnector 31 is preferably less than 20%, more preferably 10% or less, further preferably 8% or less. The thickness of the interconnector 31 may be, for example, 10 to 100 μm.

The air electrode current collecting layer 32 is arranged so as to extend between the interconnector 31 and the air electrode 6 of the adjacent power generating element portions A. The air electrode current collecting layer 32 is made of a porous material having electronic conductivity. The air electrode current collecting layer 32 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 32 may be, for example, about 50 to 500 μm.

<Glass seal part>
The glass seal portion 300 is made of crystallized glass. As the crystallized glass, for example, SiO ₂ —B ₂ O ₃ system, SiO ₂ —CaO system, MgO—B ₂ O ₃ system, or SiO ₂ —MgO system is used. The crystallized glass is most preferably SiO ₂ —MgO type.

In the crystallized glass forming the glass seal portion 300, the ratio of “volume occupied by crystal phase” (crystallinity) to the total volume is 60% or more, and “amorphous phase and impurities occupy the total volume”. The ratio of “volume” is less than 40%.

As shown in FIG. 4, the glass seal portion 300 is filled in the gap G between each through hole 221 of the manifold 200 and each fuel cell 100. The glass seal part 300 joins the fuel cell 100 and the manifold 200. Thereby, the glass seal part 300 partitions the internal space S1 and the external space. The glass seal portion 300 functions as a seal material that prevents the fuel gas in the internal space S1 of the manifold 200 from mixing with the air in the external space of the manifold 200.

As shown in FIG. 5, the glass seal part 300 includes a first region 300a and a second region 300b.

The first region 300a is within 100 μm along the surface of the fuel cell 100 centering on the cell closest contact point R1 set on the outer edge of the fuel cell 100 in a cross section perpendicular to the surface of the fuel cell 100, and The area is within 20 μm in the vertical direction from the surface of the fuel cell 100. The shape of the first region 300a changes according to the surface shape of the fuel cell 100. In the example shown in FIG. 5, since the surface of the fuel cell 100 is flat, the shape of the first region 300a is linear along the surface of the fuel cell 100.

Here, the cell closest contact point R1 of the fuel battery cell 100 indicates a position on the outer edge of the fuel battery cell 100 that is closest to the manifold closest contact point P1 of the manifold 200. The manifold closest contact point P1 of the manifold 200 indicates a position closest to the first intersection Q1 on the outer edge of the manifold 200. The first intersection Q1 is an intersection of the two intersections Q1 and Q2 between the fuel cell unit 100 and the glass seal portion 300 on the power generation element portion A side. The first intersection Q1 faces the outer space of the manifold 200, and the second intersection Q2 faces the inner space S1 of the manifold 200. The first intersection Q1 is an example of the “intersection” according to the present invention.

The second area 300b is continuous with the first area 300a. The second region 300b is, in a cross section perpendicular to the surface of the fuel cell 100, more than 100 μm along the surface of the fuel cell 100 centering on the cell closest contact point R1 of the fuel cell 100 and the surface of the fuel cell 100. Is a region of more than 20 μm in the vertical direction. The range of the second region 300b does not have to be specified in particular, but as will be described later, in the present embodiment, for convenience of measuring the porosity of the second region 300b, the fuel cell unit 100 is centered on the cell closest contact point R1. A range of more than 100 μm and not more than 1000 μm along the surface of the fuel cell 100 and more than 20 μm in the vertical direction from the surface of the fuel cell 100 is defined as the second region 300b.

The porosity of the first region 300a is 5% or more. As a result, it is possible to prevent a weak leak current from flowing from the fuel cell 100 to the manifold 200 via the glass seal portion 300 during the operation of the fuel cell stack 1.

The mechanism by which such an effect is obtained is as follows. First, during operation of the fuel cell stack 1, an electric field is generated in the gap G between the fuel cell 100 and the manifold 200. The strength of the electric field generated in the gap G is strongest at the first intersection Q1 on the power generating element portion A side of the two intersections Q1 and Q2 between the fuel cell 100 and the glass seal portion 300. Since a large voltage is applied between the first closest intersection point Q1 and the closest closest manifold point P1 to the first intersection point Q1 on the outer edge of the manifold 200, the shortest distance from the cell closest contact point R1 to the closest manifold point P1 is set. Leak current easily flows. However, since the porosity of the first region 300a of the glass seal portion 300 is 5% or more, the leakage current is structurally hindered from passing through the first region 300a. That is, the electrical insulation of the first region 300a can be structurally improved regardless of the composition of the crystallized glass forming the first region 300a. As a result, the leak current from the fuel cell unit 100 to the manifold 200 is suppressed.

The porosity of the first region 300a is preferably 7% or more, more preferably 10% or more. As a result, it is possible to further prevent the leak current from flowing from the fuel cell 100 to the manifold 200 via the glass seal portion 300.

The upper limit of the porosity of the first region 300a is not particularly limited, but may be 60% or less, for example. The upper limit of the porosity of the first region 300a is preferably 50% or less, more preferably 40% or less. As a result, the strength of the skeletal structure of the first region 300a can be maintained, and thus cracking in the first region 300a can be suppressed.

The porosity of the second region 300b is not particularly limited, but may be 4% or less, for example. The porosity of the second region 300b is preferably 3% or less, more preferably 2% or less. Accordingly, since the strength of the skeleton structure of the second region 300b can be improved, it is possible to maintain the strength of the skeleton structure of the glass seal portion 300 as a whole and suppress the occurrence of cracks in the glass seal portion 300.

The porosity of the first region 300a is measured by the following method. First, an image obtained by enlarging the cross section of the first region 300a perpendicular to the surface of the fuel cell 100 by a FE-SEM (Field Emission Scanning Electron Microscope) to 7500 times is acquired. Next, the cross-sectional image is analyzed by image analysis software HALCON manufactured by MVTec to highlight the pores. Next, in the cross-sectional image after the analysis, the total area of the solid portion made of crystallized glass and the total area of the pore portion are obtained. Next, the area occupancy of the pore portion is calculated. The area occupancy of such a pore portion is calculated in 10 fields of view of the FE-SEM, and the arithmetic mean value thereof is taken as the porosity of the first region 300a.

The porosity of the second region 300b is measured by the same method as the porosity of the first region 300a described above.

The average diameter of the pores included in the first region 300a is not particularly limited, but may be 0.1 μm to 15 μm, for example. The average diameter of the pores included in the first region 300a is preferably 0.1 μm to 10 μm. As a result, it is possible to prevent the strength of the bonding material from decreasing due to the pores.

For the average diameter of the pores included in the first region 300a, the average equivalent circle diameter of each visual field is calculated in the 10 fields of view of the cross-sectional image after analysis described above, and the average equivalent circle diameter of each visual field is calculated as the equivalent circle diameter of the pores. Obtained by averaging. The equivalent circle diameter is the diameter of a circle having the same area as the cross-sectional area of pores.

<Other structures>
As shown in FIG. 4, the cell stack 1 further includes current collecting members 400 and 500. The current collecting member 400 is provided between the adjacent fuel battery cells 100. In detail, the current collecting member 400 is arranged so as to electrically connect the fuel electrode 4 of one fuel battery cell 100 and the air electrode 6 of the other fuel battery cell 100 in series. It is provided between. The current collecting member 400 is made of, for example, a metal mesh or the like.

The current collecting member 500 is provided in each fuel cell 100. Specifically, the current collecting member 500 is provided in each fuel cell 100 in order to electrically connect the front side and the back side of each fuel cell 100 in series.

<Assembly of cell stack>
First, a crystallized glass (for example, SiO ₂ —MgO-based) material and a pore-forming material (for example, polymethylmethacrylate resin) are provided within a range of about 100 μm centering on the cell closest contact point R1 of the fuel cell 100. By applying the containing paste, a molded body of the first region 300a of the glass seal portion 300 is formed. At this time, the porosity of the first region 300a can be controlled by adjusting the addition amount of the pore-forming material. Further, the pore diameter of the first region 300a can be controlled by adjusting the particle diameter of the pore-forming material.

Next, the plurality of fuel cells 100 are aligned in a stack and fixed to a predetermined jig, and the base end portions 10a of the fuel cells 100 are inserted into the through holes 221 of the manifold 200.

Next, by filling the gap G between the fuel cell 100 and the manifold 200 with a paste containing a material of crystallized glass (eg, SiO ₂ —MgO-based), the second region 300b of the glass seal portion 300 is molded. Form the body. At this time, a pore-forming material may be added to the paste if desired. The porosity of the second region 300b can be controlled by adjusting the particle size and the addition amount of the pore-forming material.

Next, heat treatment (750 to 900° C., 1 to 10 hours) is applied to the molded body of the glass seal portion 300. By this heat treatment, the glass seal portion 300 including the first region 300a having a higher porosity than the second region 300b is formed.

<Other Embodiments>
Although the embodiments of the present invention have been described above, the present invention is not limited to these, and various modifications can be made without departing from the spirit of the present invention.

(A) In the above embodiment, a cell stack including a fuel cell is described as an example of the electrochemical cell stack, but the present invention is not limited to this. The electrochemical cell stack may include an electrochemical cell such as an electrolytic cell that produces hydrogen and oxygen from water vapor.

(B) In the above embodiment, the fuel battery cell 100 is a so-called horizontal stripe type fuel battery cell in which the plurality of power generating element portions A are arranged in the length direction of the support substrate 10. The configuration of 100 is not limited to this. The fuel cell 100 can take various forms such as a vertical stripe type and a cylindrical type. However, in the cross section perpendicular to the surface of the fuel cell 100, when both two intersections Q1 and Q2 of the fuel cell 100 and the glass seal part 300 are in contact with the power generation element part A, the outside of the manifold 200 The one facing the space is the first intersection Q1, and the one facing the internal space S1 of the manifold 200 is the second intersection Q2.

(C) In the above embodiment, the base end portion 10a of each fuel cell 100 is inserted into each through hole 221 of the manifold 200, but may be arranged outside each through hole 221. In this case, the base end portion 10 a of each fuel cell 100 is fixed to the manifold 200 via the glass seal portion 300 at a position apart from each through hole 221.

As an example of the present invention, a joined body having the structure shown in FIG. 5 was produced. However, the present invention is not limited to the examples described below.

<Joints of Examples 1 to 6 and Comparative Examples 1 and 2>
First, the fuel cell 100 and the manifold 200 in which the through hole 221 was formed were prepared.

Next, a glass paste containing SiO ₂ —MgO-based crystallized glass and a pore-forming material (polymethylmethacrylate resin) was applied in a range of about 100 μm centering on the cell nearest contact R1 of the fuel cell 100. By applying, a molded body of the first region 300a of the glass seal portion 300 was formed. At this time, the porosity of the first region 300a was changed for each sample as shown in Table 1 by adjusting the addition amount of the pore-forming material.

Next, the base end portion 10a of the fuel cell 100 fixed to the jig was inserted into the through hole 221 of the manifold 200.

Next, a glass paste containing SiO ₂ —MgO-based crystallized glass and a pore-forming material (polymethylmethacrylate resin) is filled in the gap G between the fuel cell 100 and the manifold 200, so that the glass seal portion is formed. A molded body of the second region 300b of 300 was formed. At this time, the porosity of the second region 300b was changed for each sample as shown in Table 1 by adjusting the addition amount of the pore-forming material.

Next, the molded body of the glass seal part 300 was subjected to heat treatment (850° C., 5 hours) to form the glass seal part 300.

<Measurement of leak current>
A leak current measuring circuit was produced by connecting a pair of platinum lead wires connected to the air electrode current collecting layer 32 of the fuel cell 100 and the manifold 200 to an ammeter.

Next, while operating the fuel cell unit 100 at 750° C., the leak current value was measured with an ammeter. Table 1 collectively shows the leakage current ratios of Examples 1 to 6 and Comparative Examples 1 and 2. The leak current ratio is a value obtained by dividing the measured leak current value by the leak current value of Comparative Example 1. In Table 1, samples having a leak current ratio of 0.8 or less are evaluated as ◯, and samples having a leak current ratio exceeding 0.8 are evaluated as Δ.

<Crack resistance test>
The step of raising the temperature of the fuel cell 100 from 50° C. to 750° C. at a temperature raising rate of 300° C./h and then lowering the temperature from 750° C. to 50° C. at a temperature lowering rate of 300° C./h was repeated 50 times.

Next, the outer surface of the glass seal part 300 was observed with an optical microscope to confirm the presence or absence of cracks in the glass seal part 300. In Table 1, a sample in which no crack was observed was evaluated as ◯, and a sample in which a minute crack of 500 μm or less was observed was evaluated as Δ.

As shown in Table 1, in Examples 1 to 6 in which the porosity of the first region 300a was 5% or more, compared with Comparative Examples 1 and 2 in which the porosity of the first region 300a was less than 5%, It was possible to prevent a leak current from flowing from the battery cell 100 to the manifold 200.

In addition, in Examples 1 to 5 in which the porosity of the second region 300b was 4% or less among Examples 1 to 6, compared with Example 6 in which the porosity of the second region 300b was 5%, a glass seal was used. It was possible to suppress the occurrence of cracks in the portion 300.

DESCRIPTION OF SYMBOLS 1 cell stack 100 fuel cell 200 manifold 221 through hole 300 glass seal part 300a 1st area|region 300b 2nd area 10 support substrate 11 fuel gas flow path A power generation element part P1 manifold closest contact point Q1 1st intersection point R1 cell nearest contact point

Claims (2)

An electrochemical cell having a support substrate and a power generation element portion arranged on the support substrate,
A manifold supporting the proximal end of the electrochemical cell,
A glass seal portion disposed between the electrochemical cell and the manifold,
Equipped with
In a cross section perpendicular to the surface of the electrochemical cell, the manifold has a manifold closest contact point closest to the intersection on the power generation element side of the two intersections of the electrochemical cell and the glass seal portion,
In the cross section, the electrochemical cell has a cell closest contact closest to the manifold closest contact of the manifold,
In the cross section, the glass seal part has a first region within 100 μm along the surface of the electrochemical cell centering on the cell closest contact point and within 20 μm in the vertical direction from the surface of the electrochemical cell. ,
The porosity of the first region is 5% or more,
Electrochemical cell stack. The glass seal part has a second region continuous with the first region,
The porosity of the second region is 4% or less,
The electrochemical cell stack according to claim 1.