Electrochemical apparatus

Abstract

To provide an electrochemical apparatus that can easily achieve thinning of insulating sealing materials and improve their performance. [Solution] In the electrochemical apparatus of the embodiment, the cell stack has an insulating seal material installed between a first separator and a second separator, configured to seal the space between the first separator and the second separator and to provide electrical insulation. The insulating seal material has a metal layer and an insulating layer laminated on the metal layer in the lamination direction. The insulating layer includes a glass paste base material having a glass transition temperature lower than the operating temperature of the cell stack and a filler material having a glass transition temperature higher than the operating temperature of the cell stack, with the filler material dispersed in the glass paste base material.

Description

Technical Field

[0001] Embodiments of the present invention relate to an electrochemical device.

Background Art

[0002] An electrochemical device includes an electrochemical cell configured such that an electrolyte membrane is sandwiched between a fuel electrode and an oxygen electrode. Among electrochemical cells, a solid oxide type electrochemical cell using a solid oxide as an electrolyte membrane can be used as at least one of a solid oxide fuel cell (SOFC; Solid Oxide Fuel Cell) and a solid oxide electrolysis cell (SOEC; Solid Oxide Electrolysis Cell).

[0003] When the solid oxide type electrochemical cell is used as an SOFC, under high temperature conditions, for example, a fuel electrode gas (hydrogen, carbon monoxide, etc.) supplied to the fuel electrode and an oxygen electrode gas (oxygen, air, etc.) supplied to the oxygen electrode react through the electrolyte membrane, thereby obtaining electrical energy. On the other hand, when the solid oxide type electrochemical cell is used as an SOEC, for example, under high temperature conditions, a fuel electrode gas (water vapor) supplied to the fuel electrode is electrolyzed, hydrogen is generated at the fuel electrode, and oxygen is generated at the oxygen electrode.

[0004] Generally, an electrochemical device includes a cell stack in which a plurality of electrochemical cells are stacked. The cell stack has a plurality of separators in addition to the plurality of electrochemical cells, and is configured such that each of the plurality of separators sandwiches each of the plurality of electrochemical cells in the stacking direction. In the cell stack, in order to increase the power generation output, etc., each of the plurality of electrochemical cells is electrically connected via a separator. And the cell stack is sandwiched between a pair of end plates in the stacking direction, and for example, the space between the pair of end plates is tightened using a fastening member such as a bolt.

[0005] Furthermore, an insulating seal is provided between each of the multiple separators in the cell stack. The insulating seal is, for example, a laminate in which an insulating layer is laminated on a metal layer, and the insulating layer is formed by coating the metal layer with an inorganic material such as alumina or silica. The insulating seal seals the space between each of the multiple separators to prevent leakage of the gas supplied to the electrochemical cell. At the same time, the insulating seal seal electrically insulates the space between each of the multiple separators to prevent short circuits from occurring between the multiple electrochemical cells. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-77638 [Patent Document 2] Japanese Patent Publication No. 2020-011851 [Patent Document 3] Japanese Patent Publication No. 2022-154285 [Patent Document 4] Patent No. 5476691 [Patent Document 5] Japanese Patent Publication No. 2009-064632 [Patent Document 6] Japanese Patent Application Publication No. 07-017772 [Overview of the project] [Problems that the invention aims to solve]

[0007] In electrochemical equipment, insulating seals are required to possess high mechanical strength to prevent plastic deformation and damage when compressed loads are applied to achieve sealing properties. Furthermore, insulating seals are required to have excellent heat resistance to prevent thermal deformation at the operating temperature of the electrochemical cell (e.g., 600°C to 1000°C). Finally, insulating seals are required to have excellent insulation properties to prevent short circuits.

[0008] In addition, to meet the demand for miniaturization of cell stacks, it is necessary to thin the insulating sealant material. However, conventionally, it has been difficult to achieve thin insulating sealant materials while still obtaining sufficient insulating properties. For example, when a gasket is used as the insulating sealant material, the overall thickness of the cell stack increases, making it difficult to miniaturize the cell stack. As a result, in electrochemical equipment, it is not easy to achieve both the demand for miniaturization of cell stacks and the improvement of performance (power generation performance, electrolysis performance).

[0009] Therefore, the problem that the present invention aims to solve is to provide an electrochemical apparatus that can easily achieve thinning of insulating sealing material and improve performance. [Means for solving the problem]

[0010] The electrochemical apparatus of the embodiment comprises a cell stack comprising at least an electrochemical cell in which an electrolyte membrane is interposed between a fuel electrode and an oxygen electrode, and a first separator and a second separator formed of a metallic material, wherein the electrochemical cell is interposed between the first separator and the second separator in the stacking direction, and configured such that fuel electrode gas flows through the fuel electrode and oxygen electrode gas flows through the oxygen electrode. The cell stack has an insulating seal material installed between the first separator and the second separator, configured to seal the space between the first separator and the second separator and to provide electrical insulation. The insulating seal material has a metal layer and an insulating layer laminated on the metal layer in the stacking direction. The insulating layer includes a glass paste base material with a glass transition temperature lower than the operating temperature of the cell stack and a filler material with a glass transition temperature higher than the operating temperature of the cell stack, and comprises a filler-containing portion in which the filler material is dispersed in the glass paste base material. [Brief explanation of the drawing]

[0011] [Figure 1A] Figure 1A is a schematic side cross-sectional view (xz plane) showing the electrochemical apparatus 1 according to the first embodiment. [Figure 1B]FIG. 1B is a side cross-sectional view (yz plane) schematically showing the electrochemical device 1 according to the first embodiment. [Figure 2A] FIG. 2A is a horizontal cross-sectional view (portion Z1-Z1 in FIG. 1A) schematically showing the electrochemical device 1 according to the first embodiment. [Figure 2B] FIG. 2B is a horizontal cross-sectional view (portion Z2-Z2 in FIG. 1A) schematically showing the electrochemical device 1 according to the first embodiment. [Figure 3A] FIG. 3A is a horizontal cross-sectional view (portion Z3-Z3 in FIG. 1A) schematically showing the electrochemical device 1 according to the first embodiment. [Figure 3B] FIG. 3B is a horizontal cross-sectional view (portion Z4-Z4 in FIG. 1A) schematically showing the electrochemical device 1 according to the first embodiment. [Figure 4A] FIG. 4A is a schematic diagram (xz plane) showing the configuration of the insulating sealant 14a in the electrochemical device 1 according to the first embodiment. [Figure 4B] FIG. 4B is a schematic diagram (portion X in FIG. 4A) showing the configuration of the insulating sealant 14a in the electrochemical device 1 according to the first embodiment. [Figure 5] FIG. 5 shows the relationship between the content (mass %) of the filler material F142 in the insulating layer 142 and the insulation property (dielectric breakdown voltage [V]) in the electrochemical device 1 according to the first embodiment. [Figure 6A] FIG. 6A is a schematic diagram (a portion similar to FIG. 3A) showing the configuration of the insulating sealant 14a in the electrochemical device 1 according to the second embodiment. [Figure 6B] FIG. 6B is a schematic diagram (a portion similar to FIG. 4A) showing the configuration of the insulating sealant 14a in the electrochemical device 1 according to the second embodiment. [Figure 6C] FIG. 6C is a schematic diagram (portion X in FIG. 6B) showing the configuration of the insulating sealant 14a in the electrochemical device 1 according to the second embodiment.

MODE FOR CARRYING OUT THE INVENTION

[0012] <First Embodiment> [A] Configuration of Electrochemical Device 1 Figs. 1A and 1B are side cross-sectional views schematically showing the electrochemical device 1 according to the first embodiment. Figs. 2A, 2B, 3A, and 3B are horizontal cross-sectional views schematically showing the electrochemical device 1 according to the first embodiment.

[0013] In Fig. 1A, the vertical direction is the vertical direction z, the horizontal direction is the first horizontal direction x orthogonal to the vertical direction z, and the direction perpendicular to the plane of the paper is the second horizontal direction y orthogonal to the vertical direction z and the first horizontal direction x. In Fig. 1B, the vertical direction is the vertical direction z, the horizontal direction is the second horizontal direction y, and the direction perpendicular to the plane of the paper is the first horizontal direction x. Fig. 1A shows the plane (xz plane) defined by the vertical direction z and the first horizontal direction x. Fig. 1B shows the plane (yz plane) defined by the vertical direction z and the second horizontal direction y.

[0014] Each of Figs. 2A, 2B, 3A, and 3B shows the plane (xy plane) defined by the first horizontal direction x and the second horizontal direction y. Here, Fig. 2A shows the Z1-Z1 portion in Fig. 1A, and Fig. 2B shows the Z2-Z2 portion in Fig. 1A. Fig. 3A shows the Z3-Z3 portion in Fig. 1A, and Fig. 3B shows the Z4-Z4 portion in Fig. 1A. Note that Fig. 1A corresponds to the Y1-Y1 portion in Fig. 2A, and Fig. 1B corresponds to the X1-X1 portion in Fig. 2A.

[0015] In the present embodiment, as shown in Figs. 1A and 1B, the electrochemical device 1 includes electrochemical cells 11a, 11b, separators 13a, 13b, 13c, insulating seal materials 14a, 14b, an insulating material 15, and an insulating material 20, and includes a cell stack 30 in which each part is laminated in the stacking direction (here, the vertical direction z). The electrochemical device 1 further includes a pair of end plates 12a, 12b, and the pair of end plates 12a, 12b are installed so as to sandwich the cell stack 30 in the stacking direction. Between the pair of end plates 12a, 12b, they are tightened in the stacking direction using a fastening member 17.

[0016] Furthermore, the electrochemical apparatus 1 is provided with a fuel electrode gas supply channel FG11, a fuel electrode gas discharge channel FG12, an oxygen electrode gas supply channel FG21, and an oxygen electrode gas discharge channel FG22. The fuel electrode gas supply channel FG11 includes a plurality of fuel electrode gas supply ports FG11a to FG11f. The fuel electrode gas discharge channel FG12 includes a plurality of fuel electrode gas outlet ports FG12a to FG12f. The oxygen electrode gas supply channel FG21 includes a plurality of oxygen electrode gas supply ports FG21a to FG21f. The oxygen electrode gas discharge channel FG22 includes a plurality of oxygen electrode gas outlet ports FG22a to FG22f.

[0017] The electrochemical apparatus 1 is configured such that fuel electrode gas G1 (first electrode gas) is supplied to electrochemical cells 11a and 11b via fuel electrode gas supply channel FG11, and discharged from electrochemical cells 11a and 11b via fuel electrode gas discharge channel FG12. In addition, the electrochemical apparatus 1 is configured such that oxygen electrode gas G2 (second electrode gas) is supplied to electrochemical cells 11a and 11b via oxygen electrode gas supply channel FG21, and discharged from electrochemical cells 11a and 11b via oxygen electrode gas discharge channel FG22.

[0018] In this embodiment, the case where the stacking direction is the vertical direction z is illustrated as an example, but the stacking direction may be in a direction other than the vertical direction z. Also, the number of electrochemical cells 11a, 11b, separators 13a, 13b, 13c, and insulating sealing materials 14a, 14b are not limited to the numbers shown. The fuel electrode gas supply channel FG11 and the fuel electrode gas discharge channel FG12, and the oxygen electrode gas supply channel FG21 and the oxygen electrode gas discharge channel FG22 are arranged symmetrically in a plane perpendicular to the stacking direction, but they may be arranged asymmetrically.

[0019] The details of each component of the electrochemical apparatus 1 will be explained in order below.

[0020] [A-1] Electrochemical cells 11a, 11b Each of the multiple electrochemical cells 11a, 11b is, for example, a rectangular flat plate and includes an electrolyte membrane 110, a fuel electrode 111, and an oxygen electrode 112, with the electrolyte membrane 110 interposed between the fuel electrode 111 and the oxygen electrode 112 (see Figures 1A and 1B).

[0021] Here, each of the multiple electrochemical cells 11a, 11b is, for example, a fuel electrode-supported type, in which an electrolyte membrane 110 and an oxygen electrode 112 are sequentially stacked on the upper surface of a fuel electrode 111 that functions as a support. Each of the multiple electrochemical cells 11a, 11b may have the arrangement of the fuel electrode 111 and the oxygen electrode 112 reversed, and may have a shape other than a rectangle (such as a circle).

[0022] In each of the multiple electrochemical cells 11a and 11b, the electrolyte membrane 110 contains oxide ions (O 2- The electrolyte membrane 110 is formed of an ion-conductive solid oxide (e.g., yttria-stabilized zirconia (YSZ)) that allows ions to permeate. The electrolyte membrane 110 is configured to be denser than the fuel electrode 111 and the oxygen electrode 112. The fuel electrode 111 is made of a porous electrical conductor (e.g., a cermet formed using nickel particles and ceramic particles such as YSZ). The oxygen electrode 112 is made of a porous electrical conductor (e.g., a perovskite oxide such as LaSrMnO3).

[0023] [A-2] Multiple separators 13a, 13b, 13c Each of the separators 13a, 13b, and 13c is, for example, a rectangular flat plate and is made of a metal material. Here, the separators 13a, 13b, and 13c are formed using a metal material that is conductive at the operating temperature of the cell stack 30 (for example, 600°C to 1000°C). For example, the separators 13a, 13b, and 13c are made of stainless steel, which has high heat resistance.

[0024] In the cell stack 30, each of the multiple separators 13a, 13b, and 13c is positioned to sandwich each of the multiple electrochemical cells 11a and 11b.

[0025] Although not shown in the diagram, in the cell stack 30, a current collector (not shown) is interposed between each of the multiple electrochemical cells 11a, 11b and each of the multiple separators 13a, 13b, 13c, and each of the multiple electrochemical cells 11a, 11b is electrically connected in series by the current collector (not shown) and the separators 13a, 13b, 13c. The current collector is preferably made of a conductive material with excellent oxidation resistance between separator 13a and electrochemical cell 11a, and between separator 13b and electrochemical cell 11b. Furthermore, the current collector is preferably made of a conductive material such as nickel between separator 13b and electrochemical cell 11a, and between separator 13c and electrochemical cell 11b. The current collector may be omitted depending on the electrical connection between each of the electrochemical cells 11a and 11b and each of the separators 13a, 13b, and 13c.

[0026] Furthermore, busbars B13a and B13b are installed to be electrically connected to separators 13a and 13c, respectively.

[0027] [A-2-1] Separator 13a Of the multiple separators 13a, 13b, and 13c, separator 13a (first separator) is installed on the side of the oxygen electrode 112 of the electrochemical cell 11a (see Figures 1A and 1B).

[0028] The separator 13a has a fuel electrode gas supply port FG11c and a fuel electrode gas outlet port FG12c formed as separator gas passages. The fuel electrode gas supply port FG11c and the fuel electrode gas outlet port FG12c penetrate the separator 13a in the stacking direction (see Figure 1A).

[0029] Furthermore, the separator 13a has an oxygen electrode gas supply port FG21c and an oxygen electrode gas outlet port FG22c formed as separator gas flow paths. The oxygen electrode gas supply port FG21c and the oxygen electrode gas outlet port FG22c penetrate the separator 13a in the stacking direction (see Figure 1B).

[0030] In addition, an oxygen electrode gas channel FG213a is formed in the portion of the separator 13a facing the electrochemical cell 11a. The oxygen electrode gas channel FG213a is a groove that extends in a direction perpendicular to the stacking direction (y direction). There are multiple oxygen electrode gas channels FG213a, and these multiple oxygen electrode gas channels FG213a are spaced apart in a direction perpendicular to the extension direction of the oxygen electrode gas channel FG213a (y direction) (x direction) (see Figure 1A).

[0031] [A-2-2] Separator 13b Of the multiple separators 13a, 13b, and 13c, separator 13b (second separator) has a housing space SP13b. The housing space SP13b is formed in the central part of the side surface (in this case, the top surface) of separator 13b. The housing space SP13b has a rectangular recess shape and houses the electrochemical cell 11a (see Figures 1A and 1B).

[0032] Furthermore, the separator 13b has a fuel electrode gas supply port FG11e and a fuel electrode gas outlet port FG12e formed as separator gas passages. The fuel electrode gas supply port FG11e and the fuel electrode gas outlet port FG12e penetrate the separator 13b in the stacking direction (see Figure 1A).

[0033] In the separator 13b, a fuel electrode gas channel FG113b is formed in the portion facing the electrochemical cell 11a. The fuel electrode gas channel FG113b is a groove that extends in a direction perpendicular to the stacking direction (x direction). There are multiple fuel electrode gas channels FG113b, and these multiple fuel electrode gas channels FG113b are spaced apart in a direction perpendicular to the extension direction of the fuel electrode gas channel FG113b (x direction) (see Figures 1B and 2A).

[0034] Furthermore, the separator 13b has an oxygen electrode gas supply port FG21e and an oxygen electrode gas outlet port FG22e formed as separator gas flow paths. The oxygen electrode gas supply port FG21e and the oxygen electrode gas outlet port FG22e penetrate the separator 13b in the stacking direction (see Figure 1B).

[0035] In addition, an oxygen electrode gas channel FG213b is formed in the portion of the separator 13b facing the electrochemical cell 11b. The oxygen electrode gas channel FG213b is a groove that extends in a direction perpendicular to the stacking direction (y direction). There are multiple oxygen electrode gas channels FG213b, and these multiple oxygen electrode gas channels FG213b are spaced apart in a direction perpendicular to the extension direction of the oxygen electrode gas channel FG213b (y direction) (x direction) (see Figures 1A and 2B).

[0036] In this embodiment, in the separator 13b, each of the fuel electrode gas supply port FG11e, fuel electrode gas outlet port FG12e, oxygen electrode gas supply port FG21e, and oxygen electrode gas outlet port FG22e is singular and has a circular cross-section in a plane (xy plane) perpendicular to the stacking direction. Furthermore, in the separator 13b, each of the fuel electrode gas supply port FG11e, fuel electrode gas outlet port FG12e, oxygen electrode gas supply port FG21e, and oxygen electrode gas outlet port FG22e is formed to be arranged concentrically in a plane (xy plane) perpendicular to the stacking direction (see Figures 2A and 2B).

[0037] Although not shown in the illustration, in the separator 13a, the fuel electrode gas supply port FG11c, fuel electrode gas outlet port FG12c, oxygen electrode gas supply port FG21c, and oxygen electrode gas outlet port FG22c are formed in the same manner as the fuel electrode gas supply port FG11e, fuel electrode gas outlet port FG12e, oxygen electrode gas supply port FG21e, and oxygen electrode gas outlet port FG22e, respectively.

[0038] [A-2-3] Separator 13c Of the multiple separators 13a, 13b, and 13c, separator 13c has a housing space SP13c. The housing space SP13c is formed in the central part of the surface (in this case, the top surface) on the side of separator 13b in separator 13c. The housing space SP13c has a rectangular recess shape and houses the electrochemical cell 11b (see Figures 1A and 1B).

[0039] In the separator 13c, a fuel electrode gas channel FG113c is formed in the portion facing the electrochemical cell 11b. The fuel electrode gas channel FG113c is a groove that extends in a direction perpendicular to the stacking direction (x direction). There are multiple fuel electrode gas channels FG113c, and these multiple fuel electrode gas channels FG113c are spaced apart in a direction perpendicular to the extension direction of the fuel electrode gas channel FG113c (x direction) (see Figure 1B).

[0040] [A-3] Multiple insulating sealants 14a, 14b Each of the multiple insulating sealants 14a and 14b is interposed between each of the multiple separators 13a, 13b, and 13c in the cell stack 30 (see Figures 1A and 1B). The detailed configuration of each of the multiple insulating sealants 14a and 14b will be described later.

[0041] [A-3-1] Insulating sealant 14a Of the multiple insulating sealants 14a and 14b, insulating sealant 14a seals the space between separator 13a and separator 13b, and also provides electrical insulation between separator 13a and separator 13b.

[0042] The insulating sealant 14a is, for example, a rectangular frame-like shape with an opening K14a formed in the central part. The opening K14a of the insulating sealant 14a is interposed between the oxygen electrode gas channel FG213a of the separator 13a and the oxygen electrode 112 of the electrochemical cell 11a in the stacking direction. Here, the insulating sealant 14a has a planar shape that is smaller than that of the separator 13b, but it may be the same as that of the separator 13b (see Figures 1A, 1B, and 3A).

[0043] The insulating seal material 14a has a fuel electrode gas supply port FG11d, a fuel electrode gas outlet port FG12d, an oxygen electrode gas supply port FG21d, and an oxygen electrode gas outlet port FG22d provided around the opening K14a. In the insulating seal material 14a, each of the fuel electrode gas supply port FG11d, fuel electrode gas outlet port FG12d, oxygen electrode gas supply port FG21d, and oxygen electrode gas outlet port FG22d is singular and has a rectangular cross-section in a plane (xy plane) perpendicular to the lamination direction (see Figure 3A).

[0044] The fuel electrode gas supply port FG11d is interposed between the fuel electrode gas supply port FG11c of separator 13a and the housing space SP13b of separator 13b in the stacking direction. The fuel electrode gas outlet port FG12d is interposed between the fuel electrode gas outlet port FG12c of separator 13a and the housing space SP13b of separator 13b in the stacking direction (see Figure 1A).

[0045] The oxygen electrode gas supply port FG21d is interposed between the oxygen electrode gas supply port FG21d of separator 13a and the containment space SP13b of separator 13b in the stacking direction. The oxygen electrode gas outlet port FG22d is interposed between the oxygen electrode gas outlet port FG22d of separator 13a and the containment space SP13b of separator 13b in the stacking direction (see Figure 1B).

[0046] [A-3-2] Insulating sealant 14b Of the multiple insulating seal materials 14a and 14b, insulating seal material 14b seals the space between separator 13b and separator 13c, and also provides electrical insulation between separator 13b and separator 13c.

[0047] The insulating seal material 14b, like the insulating seal material 14a, is, for example, a rectangular frame-like shape with an opening K14b formed in the central part. The opening K14b of the insulating seal material 14b is interposed in the stacking direction between the oxygen electrode gas flow path FG213b of the separator 13b and the oxygen electrode 112 of the electrochemical cell 11b. Here, the insulating seal material 14b has a planar shape that is smaller than that of the separator 13b, but it may be the same as that of the separator 13b (see Figures 1A, 1B, and 3B).

[0048] The insulating seal material 14b has a fuel electrode gas supply port FG11f, a fuel electrode gas outlet port FG12f, an oxygen electrode gas supply port FG21f, and an oxygen electrode gas outlet port FG22f provided around the opening K14b. In the insulating seal material 14b, each of the fuel electrode gas supply port FG11f, fuel electrode gas outlet port FG12f, oxygen electrode gas supply port FG21f, and oxygen electrode gas outlet port FG22f is singular and has a rectangular cross-section in a plane (xy plane) perpendicular to the lamination direction (see Figure 3B).

[0049] The fuel electrode gas supply port FG11f is interposed in the stacking direction between the fuel electrode gas supply port FG11e of separator 13b and the containment space SP13c of separator 13c. The fuel electrode gas outlet port FG12f is interposed in the stacking direction between the fuel electrode gas outlet port FG12e of separator 13b and the containment space SP13c of separator 13c (see Figure 1A).

[0050] The oxygen electrode gas supply port FG21f is interposed between the oxygen electrode gas supply port FG21e of separator 13b and the containment space SP13c of separator 13c in the stacking direction. The oxygen electrode gas outlet port FG22f is interposed between the oxygen electrode gas outlet port FG22e of separator 13b and the containment space SP13c of separator 13c in the stacking direction (see Figure 1B).

[0051] [A-4] A pair of end plates 12a, 12b The pair of end plates 12a and 12b are positioned to sandwich the cell stack 30 in the stacking direction (see Figures 1A and 1B). Each of the pair of end plates 12a and 12b is, for example, a rectangular flat plate and is made of a metal material such as stainless steel with high heat resistance.

[0052] [A-4-1] End plate 12a Of the pair of end plates 12a and 12b, end plate 12a (first end plate) is installed adjacent to separator 13a in the stacking direction, separated by a gap (see Figures 1A and 1B).

[0053] The end plate 12a has a fuel electrode gas supply port FG11a and a fuel electrode gas outlet FG12a formed as end plate gas passages. The fuel electrode gas supply port FG11a and the fuel electrode gas outlet FG12a penetrate the end plate 12a in the stacking direction (see Figure 1A). In addition, the end plate 12a has an oxygen electrode gas supply port FG21a and an oxygen electrode gas outlet FG22a formed as end plate gas passages. The oxygen electrode gas supply port FG21a and the oxygen electrode gas outlet FG22a penetrate the end plate 12a in the stacking direction (see Figure 1B).

[0054] On the end plate 12a, a fuel electrode gas supply pipe H11, a fuel electrode gas discharge pipe H12, an oxygen electrode gas supply pipe H21, and an oxygen electrode gas discharge pipe H22 are installed on the side opposite to the side where the separator 13a is located (the top surface in Figures 1A and 1B). The fuel electrode gas supply pipe H11 communicates with the fuel electrode gas supply port FG11a. The fuel electrode gas discharge pipe H12 communicates with the fuel electrode gas discharge port FG12a. The oxygen electrode gas supply pipe H21 communicates with the oxygen electrode gas supply port FG21a. The oxygen electrode gas discharge pipe H22 communicates with the oxygen electrode gas discharge port FG22a. In this embodiment, the fuel electrode gas supply pipe H11, the fuel electrode gas discharge pipe H12, the oxygen electrode gas supply pipe H21, and the oxygen electrode gas discharge pipe H22 are each connected to the end plate 12a such that their pipe axes are aligned with the stacking direction (see Figures 1A and 1B).

[0055] [A-4-2] End plate 12b Of the pair of end plates 12a and 12b, end plate 12b (second end plate) is installed adjacent to separator 13c in the stacking direction, separated by a gap (see Figures 1A and 1B).

[0056] [A-5] Insulating material 15 The insulating material 15 is provided in the cell stack 30 on the side of the separator 13c opposite to the side on which the electrochemical cell 11b is provided (in Figures 1A and 1B, the lower surface of the separator 13c). In other words, the insulating material 15 is interposed between the separator 13c and the end plate 12b in the stacking direction. The insulating material 15 is, for example, a rectangular plate-like body made of an insulating material composed of minerals such as mica or vermiculite.

[0057] [A-6] Insulating material 20 The insulating material 20 is provided in the cell stack 30 on the side of the separator 13a opposite to the side on which the electrochemical cell 11a is provided (the upper surface of the separator 13a in Figures 1A and 1B). In other words, the insulating material 20 is interposed between the separator 13a and the end plate 12a in the stacking direction. The insulating material 20 is, for example, a rectangular plate-like body made of an insulating material composed of minerals such as mica or vermiculite.

[0058] The insulating material 20 has a fuel electrode gas supply port FG11b and a fuel electrode gas outlet port FG12b formed therein. The fuel electrode gas supply port FG11b and the fuel electrode gas outlet port FG12b penetrate the insulating material 20 in the stacking direction (see Figure 1A). The insulating material 20 also has an oxygen electrode gas supply port FG21b and an oxygen electrode gas outlet port FG22b formed therein. The oxygen electrode gas supply port FG21b and the oxygen electrode gas outlet port FG22b penetrate the insulating material 20 in the stacking direction (see Figure 1B).

[0059] [A-7] Fastening member 17 The fastening members 17 are, for example, bolts and nuts, and fastening is performed by inserting the shafts of the bolts into bolt holes that penetrate each part constituting the electrochemical apparatus 1 in the stacking direction, thereby applying a load in the stacking direction. There are multiple bolt holes, and multiple bolt holes are formed, for example, in the peripheral part of each part. Alternatively, tightening may be performed by pressing between a pair of end plates 12a and 12b using a press mechanism.

[0060] [B] Operation of electrochemical apparatus 1 This section describes the operation of electrochemical apparatus 1. Specifically, it describes the case where the electrochemical cells 11a and 11b constituting electrochemical apparatus 1 are used as SOFCs.

[0061] When the electrochemical cells 11a and 11b are used as SOFCs, under high-temperature conditions, fuel electrode gas G1 containing, for example, hydrogen, which is a fuel gas, is supplied to the fuel electrode 111 constituting the electrochemical cells 11a and 11b, and oxygen electrode gas G2 containing, for example, oxygen (air), which is an oxidizing gas, is supplied to the oxygen electrode 112 constituting the electrochemical cells 11a and 11b (see Figures 1A and 1B).

[0062] Specifically, the fuel electrode gas G1 is introduced from the fuel electrode gas supply pipe H11 into the fuel electrode gas supply channel FG11. In the fuel electrode gas supply channel FG11, the fuel electrode gas G1 flows sequentially through a plurality of fuel electrode gas supply ports FG11a, FG11b, FG11c, and FG11d, before being introduced into the containment space SP13b of the separator 13b, and then supplied to the fuel electrode 111 of the electrochemical cell 11a via the fuel electrode gas channel FG113b. Furthermore, in the fuel electrode gas supply channel FG11, the fuel electrode gas G1 flows sequentially through multiple fuel electrode gas supply ports FG11a, FG11b, FG11c, FG11d, FG11e, and FG11f before being introduced into the containment space SP13b of the separator 13b and supplied to the fuel electrode 111 of the electrochemical cell 11b via the fuel electrode gas supply channel FG113c (see Figure 1A).

[0063] Oxygen electrode gas G2 is introduced from the oxygen electrode gas supply pipe H21 into the oxygen electrode gas supply channel FG21. In the oxygen electrode gas supply channel FG21, the oxygen electrode gas G2 flows sequentially through multiple oxygen electrode gas supply ports FG21a, FG21b, and FG21c, and then is supplied to the oxygen electrode 112 of the electrochemical cell 11a via the oxygen electrode gas channel FG213a. In addition, in the oxygen electrode gas supply channel FG21, the oxygen electrode gas G2 flows sequentially through multiple oxygen electrode gas supply ports FG21a, FG21b, FG21c, FG21d, and FG21e, and then is supplied to the oxygen electrode 112 of the electrochemical cell 11b via the oxygen electrode gas channel FG213b (see Figure 1B).

[0064] As a result, in each of the multiple electrochemical cells 11a and 11b, at the oxygen electrode 112, oxygen (O2) accepts electrons and forms oxide ions (O2). 2-) is generated. And then the oxide ion (O 2- ) moves from the oxygen electrode 112 side to the fuel electrode 111 side in the electrolyte membrane 110. At the fuel electrode 111, oxide ions (O 2- ) reacts with hydrogen (H2) to produce water, and oxide ions (O 2- ) electrons are released. Oxide ions (O 2- Electrons emitted from the ) move from the fuel electrode 111 to the oxygen electrode 112 via an external load. In this way, power is generated in each of the multiple electrochemical cells 11a and 11b. The power generated in each of the multiple electrochemical cells 11a and 11b is output through busbars B13a and B13b (see Figures 1A and 1B).

[0065] Subsequently, the fuel electrode gas G1 flows from the fuel electrode 111 in each of the multiple electrochemical cells 11a and 11b through the fuel electrode gas discharge channel FG12 to the fuel electrode gas discharge pipe H12 and is discharged to the outside. At the same time, the oxygen electrode gas G2 flows from the oxygen electrode 112 in each of the multiple electrochemical cells 11a and 11b through the oxygen electrode gas discharge channel FG22 to the oxygen electrode gas discharge pipe H22 and is discharged to the outside.

[0066] Specifically, the fuel electrode gas G1 flows from the electrochemical cell 11a into the containment space SP13b of the separator 13b, and then sequentially flows through multiple fuel electrode gas outlets FG12d, FG12c, FG12b, FG12b, FG12a in the fuel electrode gas discharge channel FG12 before being discharged from the fuel electrode gas discharge pipe H12. Alternatively, the fuel electrode gas G1 flows from the electrochemical cell 11b into the containment space SP13c of the separator 13c, and then sequentially flows through multiple fuel electrode gas outlets FG12f, FG12e, FG12d, FG12c, FG12b, FG12b, FG12a in the fuel electrode gas discharge channel FG12 before being discharged from the fuel electrode gas discharge pipe H12 (see Figure 1A).

[0067] The oxygen electrode gas G2 flows from the electrochemical cell 11a into the containment space SP13b of the separator 13b, and then sequentially flows through multiple oxygen electrode gas outlets FG22d, FG22c, FG22b, FG22b, FG22a in the oxygen electrode gas discharge channel FG22 before being discharged from the oxygen electrode gas discharge pipe H22. The oxygen electrode gas G2 flows from the electrochemical cell 11b into the containment space SP13c of the separator 13c, and then sequentially flows through multiple oxygen electrode gas outlets FG22f, FG22e, FG22d, FG22c, FG22b, FG22b, FG22a in the oxygen electrode gas discharge channel FG22 before being discharged from the oxygen electrode gas discharge pipe H22 (see Figure 1B).

[0068] As already explained, the electrochemical apparatus 1 can be operated not only by using each of the multiple electrochemical cells 11a and 11b as an SOFC, but also by using each of the multiple electrochemical cells 11a and 11b as an SOEC. When using each of the multiple electrochemical cells 11a and 11b as an SOEC, for example, fuel electrode gas G1 containing water vapor is supplied to the fuel electrode 111, and by electrolyzing the water vapor, hydrogen is generated at the fuel electrode 111 and oxygen is generated at the oxygen electrode 112. When performing electrolysis, power is supplied to each of the multiple electrochemical cells 11a and 11b via busbars B13a and B13b (see Figures 1A and 1B).

[0069] [C] Detailed configuration of insulating sealant 14a Figures 4A and 4B are schematic diagrams showing the configuration of the insulating seal material 14a in the electrochemical apparatus 1 according to the first embodiment.

[0070] Figure 4A shows a magnified view of the same cross-section (xz plane) as in Figure 1A. Figure 4B shows a further magnified view of the X portion in Figure 4A. Note that the insulating sealant 14b is constructed similarly to the insulating sealant 14a, so its explanation is omitted.

[0071] As shown in Figure 4A, the insulating seal material 14a of this embodiment has a metal layer 141 and an insulating layer 142.

[0072] [C-1] Metal layer 141 The metal layer 141 is, for example, a plate-like body made of a metallic material. The metal layer 141 is made of a material that has mechanical strength that does not undergo plastic deformation or fracture at the operating temperature of the cell stack 30 (see Figure 1A, etc.) (for example, 600°C to 1000°C). The metal layer 141 is made of a stainless steel material with high heat resistance, similar to the separators 13a, 13b, and 13c.

[0073] [C-2] Insulating layer 142 The insulating layer 142 is laminated on the metal layer 141 in the stacking direction (here, the vertical direction z) of the cell stack 30 (see Figure 1A, etc.). The insulating layer 142 is formed using an insulating material.

[0074] In this embodiment, the insulating layer 142 includes a glass paste base material P142 and a filler material F142, as shown in Figure 4B. The insulating layer 142 is formed, for example, by coating the surface of the metal layer 141 with a paste coating solution in which the filler material F142 is dispersed on the glass paste base material P142, and then heating it at 100 to 200°C to evaporate the solvent. The coating is performed, for example, by screen printing or a dispenser.

[0075] The insulating layer 142 is formed, for example, to have a thickness of 50 μm or more and 60 μm or less.

[0076] [C-2-1] Glass paste base material P142 Here, the glass paste base material P142 is a base material composed of a glass material with a glass transition temperature (Tg) lower than the operating temperature of the cell stack 30. The material for the glass paste base material P142 can be any glass powder that has a glass transition temperature lower than the operating temperature and satisfies the desired coefficient of thermal expansion, for example, GM31107 glass powder manufactured by SCHOTT AG.

[0077] [C-2-2] Filler material F142 The filler material F142 is a powder composed of a material whose glass transition temperature (Tg) is higher than the operating temperature of the cell stack 30. In the insulating layer 142, the filler material F142 is dispersed in the glass paste base material P142, which is the dispersion medium. In other words, the insulating layer 142 consists of a filler-containing portion in which the filler material F142 is dispersed in the glass paste base material P142. The material of the glass paste base material P142 is an inorganic material such as alumina, boron nitride, or magnesium oxide.

[0078] [C-2-3] Function of insulating layer 142 As described above, in the insulating layer 142 of this embodiment, the glass transition temperature (Tg) of the glass paste base material P142 is lower than the operating temperature of the cell stack 30, while the glass transition temperature (Tg) of the filler material F142 is higher than the operating temperature of the cell stack 30. Therefore, in the insulating layer 142 of this embodiment, at the operating temperature of the cell stack 30, the glass paste base material P142 flows, while the insulating layer 142 does not flow and maintains its shape.

[0079] Therefore, in this embodiment, when operating the cell stack 30 using the electrochemical cells 11a and 11b as SOFC or SOEC, an electrical insulating state is maintained between the separator 13a that contacts the insulating seal material 14a and the metal layer 141 that constitutes the insulating seal material 14a by the filler material F142. As a result, in this embodiment, the occurrence of short circuits can be easily suppressed, thereby improving the performance of the electrochemical apparatus. Furthermore, since the insulating layer 142 is composed of a glass paste base material P142 and a filler material F142, it is easy to thin the insulating seal material 14a, and the cell stack 30 can be miniaturized. In addition, in this embodiment, cost reduction is possible.

[0080] [C-2-4] Average grain size of filler material F142 In the insulating layer 142, the filler material F142 preferably has an average particle size in the range of 7 μm or more and 13 μm or less. If the value is below the lower limit of the above range, the insulation distance between the metal layers 141 cannot be sufficiently met, which may result in a failure to obtain the desired insulation performance. If the value exceeds the upper limit of the above range, the glass paste base material P142 may not penetrate sufficiently near the filler material F142, which may result in a failure to obtain the desired sealing characteristics.

[0081] [C-2-5] Content of filler material F142 In the insulating layer 142 consisting of the filler-containing portion, it is preferable that the content of the filler material F142 is in the range of 10% by mass or more and 20% by mass or less. If it is below the lower limit of the above range, the insulating properties of the insulating seal material 14a may not be fully exhibited, and the possibility of short circuits may increase. Furthermore, if it exceeds the upper limit of the above range, the viscosity of the paste coating liquid in which the filler material F142 is dispersed in the glass paste base material P142 becomes significantly higher, making it difficult to uniformly apply the paste coating liquid to the surface of the metal layer 141 that forms the insulating layer 142.

[0082] Figure 5 shows the relationship between the content (mass%) (=x in the approximation formula) of filler material F142 in the insulating layer 142 and the insulating properties (dielectric breakdown voltage [V]) (=y in the approximation formula) in the electrochemical apparatus 1 according to the first embodiment.

[0083] Figure 5 shows the results when the insulating layer 142 was fabricated under the following conditions. • Glass paste base material P142 Materials: Glass powder, binder resin • Glass transition temperature: 533°C (glass powder) • Filler material F142 • Material: Alumina • Glass transition temperature: As it is a crystalline material, it does not have a glass transition temperature. Its melting point is generally around 2000°C. ·Average particle size: 7~13μm

[0084] Furthermore, in Figure 5, the insulating properties (dielectric breakdown voltage [V]) are measured using a test specimen consisting of two metal layers 141 coated with paste coating liquid, stacked on top of each other and subjected to a constant load. After heating to 700°C, a DC voltage is applied from one side of the metal layer 141 at a rate of 1 V / s, and the voltage value is measured when a short circuit is created. The approximate formula shown in Figure 5 is derived using data for filler material F142 content (mass%) of 5 mass%, 10 mass%, and 15 mass%.

[0085] As can be seen from Figure 5, when the content of filler material F142 is 7.5% by mass or more, the dielectric breakdown voltage [V] indicating the insulating properties is 5V or more. Therefore, the insulating properties of the insulating seal material 14a are fully exhibited, and the possibility of short circuits can be reduced.

[0086] <Second Embodiment> [A] Detailed configuration of insulating sealant 14a Figures 6A to 6C are schematic diagrams showing the configuration of the insulating seal material 14a in the electrochemical apparatus 1 according to the second embodiment.

[0087] Figure 6A shows the same area as in Figure 3A. Figure 6B shows the same area as in Figure 4A. Figure 6C shows a further magnified view of area X in Figure 6B.

[0088] As shown in each figure, in this embodiment, the insulating seal material 14a has a metal layer 141 and an insulating layer 142, similar to the first embodiment (see Figure 4). However, the insulating seal material 14a of this embodiment differs from the first embodiment (see Figure 4) in the configuration of the insulating layer 142. Except for this point and related points, it is the same as the first embodiment. Therefore, in this embodiment, explanations of overlapping matters will be omitted as appropriate.

[0089] In the insulating sealant 14a of this embodiment, the insulating layer 142 includes a filler-free portion 1420 and a filler-containing portion 1421.

[0090] The filler-free portion 1420 consists of the glass paste base material P142. Unlike the filler-containing portion 1421, the filler-free portion 1420 does not contain the filler material F142.

[0091] The filler-containing portion 1421 includes a glass paste base material P142 and a filler material F142, with the filler material F142 dispersed in the glass paste base material P142.

[0092] In this embodiment, the filler-containing portion 1421 is provided to cover the edge portion located around the metal layer 141 on the surface (top surface in the figure) on which the insulating layer 142 is laminated.

[0093] In this embodiment, the filler-containing portion 1421 is provided to cover the edge portions located around the openings (K14a, FG11d, FG12d, FG21d, FG22d) that penetrate the insulating seal material 14a in the lamination direction (z direction in the figure). Specifically, the filler-containing portion 1421 is provided to cover the edge portion located around the opening K14a on the surface (top surface in the figure) where the insulating layer 142 is laminated in the metal layer 141. Furthermore, the filler-containing portion 1421 is provided to cover the edge portions located around the fuel electrode gas supply port FG11d, the fuel electrode gas outlet port FG12d, the oxygen electrode gas supply port FG21d, and the oxygen electrode gas outlet port FG22d on the surface (top surface in the figure) where the insulating layer 142 is laminated in the metal layer 141. The filler-containing portion 1421 is formed to cover, for example, an area up to 10 mm from the end face of the edge portion.

[0094] The filler-free portion 1420 is provided to cover the portion of the metal layer 141 where the insulating layer 142 is laminated (the upper surface in the figure) that does not have a filler-containing portion 1421.

[0095] [B] Function of insulating layer 142 Short circuits between the metal layer 141 constituting the insulating seal material 14a and the separator 13a in contact with the insulating seal material 14a often occur because the metal layer 141 is not parallel to the separator 13a but tilted, and the electric field increases as the edges of the separator 13a and the metal layer 141 come closer together.

[0096] In the filler-containing portion 1421 of this embodiment, the glass transition temperature (Tg) of the glass paste base material P142 is lower than the operating temperature of the cell stack 30, while the glass transition temperature (Tg) of the filler material F142 is higher than the operating temperature of the cell stack 30. Therefore, in the insulating layer 142 of this embodiment, at the operating temperature of the cell stack 30, the glass paste base material P142 in the filler-containing portion 1421 flows, while the glass paste base material P142 does not flow and maintains its shape.

[0097] Therefore, in this embodiment, when operating the cell stack 30 using the electrochemical cells 11a and 11b as SOFC or SOEC, an electrically insulating state is maintained between the separator 13a that contacts the insulating seal material 14a and the metal layer 141 constituting the insulating seal material 14a by the filler material F142 in the filler-containing portion 1421. As a result, in this embodiment, as in the first embodiment, the occurrence of short circuits can be easily suppressed, thereby improving the performance of the electrochemical apparatus. Furthermore, in the insulating seal material 14a of this embodiment, the amount of filler material F142 used can be reduced compared to the above embodiment, thus enabling cost reduction.

[0098] <Other> While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0099] 1: Electrochemical apparatus, 11a: Electrochemical cell, 11b: Electrochemical cell, 12a: End plate, 12b: End plate, 13a: Separator, 13a: Multiple separators, 13b: Separator, 13c: Separator, 14a: Insulating sealant, 14b: Insulating sealant, 15: Insulating material, 17: Fastening member, 20: Insulating material, 30: Cell stack, 110: Electrolyte membrane, 111: Fuel electrode, 112: Oxygen electrode, 141: Metal layer, 142: Insulating layer, 1420: Filler-free portion, 1421 :Filler-containing section, F142:Filler material, FG11:Fuel electrode gas supply passage, FG113b:Fuel electrode gas passage, FG113c:Fuel electrode gas passage, FG11a:Fuel electrode gas supply port, FG11b:Fuel electrode gas supply port, FG11c:Fuel electrode gas supply port, FG11d:Fuel electrode gas supply port, FG11e:Fuel electrode gas supply port, FG11f:Fuel electrode gas supply port, FG12a:Fuel electrode gas outlet, FG12b:Fuel electrode gas outlet, FG12c:Fuel electrode gas outlet, FG 12d: Fuel electrode gas outlet, FG12e: Fuel electrode gas outlet, FG12f: Fuel electrode gas outlet, FG21: Oxygen electrode gas supply channel, FG213a: Oxygen electrode gas channel, FG213b: Oxygen electrode gas channel, FG21a: Oxygen electrode gas supply port, FG21b: Oxygen electrode gas supply port, FG21c: Oxygen electrode gas supply port, FG21d: Oxygen electrode gas supply port, FG21e: Oxygen electrode gas supply port, FG21f: Oxygen electrode gas supply port, FG22: Oxygen electrode gas outlet channel, FG22a: Oxygen electrode Gas outlet section, FG22b: Oxygen electrode gas outlet section, FG22c: Oxygen electrode gas outlet section, FG22d: Oxygen electrode gas outlet section, FG22e: Oxygen electrode gas outlet section, FG22f: Oxygen electrode gas outlet section, G1: Fuel electrode gas, G2: Oxygen electrode gas, H11: Fuel electrode gas supply pipe, H12: Fuel electrode gas outlet pipe, H21: Oxygen electrode gas supply pipe, H22: Oxygen electrode gas outlet pipe, K14a: Opening, K14b: Opening, P142: Glass paste base material, SP13b: Containment space, SP13c: Containment space,

Claims

1. A cell stack comprising at least an electrochemical cell in which an electrolyte membrane is interposed between a fuel electrode and an oxygen electrode, and a first separator and a second separator formed of a metallic material, wherein in the stacking direction the electrochemical cell is interposed between the first separator and the second separator, and configured such that the fuel electrode gas flows through the fuel electrode and the oxygen electrode gas flows through the oxygen electrode. An electrochemical apparatus comprising, The aforementioned cell stack is An insulating seal material is installed between the first separator and the second separator, configured to seal the space between the first separator and the second separator and to provide electrical insulation. It has, The aforementioned insulating sealing material is Metal layer, In the aforementioned stacking direction, an insulating layer is stacked on the metal layer and It has, The insulating layer comprises a glass paste base material with a glass transition temperature lower than the operating temperature of the cell stack and a filler material with a glass transition temperature higher than the operating temperature of the cell stack, and includes a filler-containing portion in which the filler material is dispersed in the glass paste base material. Electrochemical apparatus.

2. The insulating sealing material includes an opening that penetrates in the stacking direction, The insulating layer is Filler-free portion made of the aforementioned glass paste base material It further includes, The filler-containing portion is provided so as to cover at least one of the edge portions located around the metal layer and the edge portions located around the opening, on the surface in which the insulating layer is laminated in the metal layer. The filler-free portion is provided so as to cover the portion of the surface on which the insulating layer is laminated in the metal layer that does not contain the filler-containing portion. The electrochemical apparatus according to claim 1.

3. The filler material has an average particle size in the range of 7 μm or more and 13 μm or less. The electrochemical apparatus according to claim 1.

4. In the insulating layer, the filler-containing portion has a filler content in the range of 5% by mass or more and 20% by mass or less. The electrochemical apparatus according to claim 1.

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