Electrochemical device

Abstract

To provide an electrochemical device in which characteristics such as sealing properties are improved and improvements in power generation performance and electrolysis performance can be easily realized.SOLUTION: In an embodiment, a first end plate is provided with an end plate gas flow path, and a metal member is provided with a metal member gas flow path communicating with the end plate gas flow path. A gasket for sealing between the end plate gas flow path and the metal member gas flow path is installed between the first end plate and the metal member. A gasket is formed of a metal material. An insulating film is formed so as to cover a surface of the metal member facing the first end plate in a stacking direction.SELECTED DRAWING: Figure 5A

Description

[Technical Field]

[0001] FIELD OF THE INVENTION Embodiments of the present invention relate to electrochemical devices. [Background technology]

[0002] The electrochemical device has an electrochemical cell configured such that an electrolyte membrane is sandwiched between a hydrogen electrode and an oxygen electrode. Among electrochemical cells, a solid oxide electrochemical cell using a solid oxide for the electrolyte membrane can be used as at least one of a solid oxide fuel cell (SOFC) and a solid oxide electrolysis cell (SOEC).

[0003] When a solid oxide electrochemical cell is used as an SOFC, for example, hydrogen supplied to the hydrogen electrode and oxygen supplied to the oxygen electrode react with each other through an electrolyte membrane under high-temperature conditions to generate electrical energy. On the other hand, when a solid oxide electrochemical cell is used as an SOEC, for example, water (water vapor) is electrolyzed under high-temperature conditions to generate hydrogen at the hydrogen electrode and oxygen 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 so that each of the plurality of electrochemical cells is sandwiched between the plurality of separators in the stacking direction. In the cell stack, the plurality of electrochemical cells are electrically connected to each other via the separators to increase the power generation output, etc. The cell stack is sandwiched between a pair of end plates, and the pair of end plates are fastened together using fastening members such as bolts, for example. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5701697 [Patent Document 2] Patent Publication No. 2005-174658 [Patent Document 3] JP 6-325779 [Patent Document 4] Patent Publication No. 2022-187996 [Patent Document 5] Patent No. 4438295 [Patent Document 6] Patent No. 4512845 [Patent Document 7] Patent No. 4696470 [Patent Document 8] Patent No. 5023429 [Patent Document 9] Patent No. 7273694 [Patent Document 10] Special Publication 2008-510288 [Patent Document 11] Patent Publication No. 2017-135090 [Patent Document 12] Special Publication 2008-535149 [Patent Document 13] Patent Publication No. 10-233221 [Patent Document 14] Patent Publication No. 2023-127629 Summary of the Invention [Problem to be solved by the invention]

[0006] An end plate and a separator arranged adjacent to each other at one end in the stacking direction are each provided with a gas flow path for the hydrogen electrode gas flowing through the hydrogen electrode and the oxygen electrode gas flowing through the oxygen electrode. A sealant is provided between the end plate and the separator arranged adjacent to each other at one end in the stacking direction to seal the gap between the gas flow path formed in the end plate and the gas flow path formed in the separator and prevent gas leakage.

[0007] In electrochemical devices, the sealing material is required to have high mechanical strength so as not to be broken due to plastic deformation when a compressive load is applied to obtain sealing properties. The sealing material is also 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). The sealing material also needs to have insulating properties to prevent short circuits from occurring between the electrochemical cell and the outside. For this reason, the sealing material is formed using minerals such as mica and vermiculite.

[0008] Minerals such as mica and vermiculite have high insulating properties, but because they have a layered structure, gases may diffuse between the mineral layers or through the interface with the material laminated on the mineral, making it difficult to sufficiently reduce leakage. To reduce leakage, it has been proposed to apply a glassy material to the surface of a mineral sealing material, but the effect of this method in reducing leakage is insufficient.

[0009] Due to the above-mentioned circumstances, it has been difficult to obtain sufficient properties such as sealing performance in the conventional electrochemical device, which may result in a decrease in power generation performance and electrolysis performance.

[0010] Therefore, an object of the present invention is to provide an electrochemical device that has improved properties such as sealing ability and that can easily achieve improved power generation performance and electrolysis performance. [Means for solving the problem]

[0011] An electrochemical device according to an embodiment includes a cell stack, a first end plate, and a second end plate. The cell stack includes at least electrochemical cells in which an electrolyte membrane is interposed between a first electrode and a second electrode, and a metal member formed of a metal material. The cell stack is stacked so that the electrochemical cells and the metal member are electrically connected in the stacking direction, and is configured so that a first electrode gas flows through the first electrode and a second electrode gas flows through the second electrode. The first end plate and the second end plate are disposed to sandwich the cell stack in the stacking direction and are formed of a metal material. In the electrochemical device, the first end plate and the metal member are arranged adjacent to each other in the stacking direction. The first end plate is provided with an end plate gas flow channel through which at least one of the first electrode gas and the second electrode gas flows. The metal member is provided with a metal member gas flow channel that communicates with the end plate gas flow channel. A gasket is provided between the first end plate and the metal member to seal the end plate gas flow path and the metal member gas flow path, and the gasket is made of a metal material. An insulating film is formed to cover at least one of a first surface of the metal member facing the first end plate in the stacking direction, a second surface of the first end plate facing the metal member in the stacking direction, and a third surface of the first end plate located opposite the second surface in the stacking direction. [Brief explanation of the drawings]

[0012] [Figure 1A] FIG. 1A is a side cross-sectional view (xz plane) that schematically shows an electrochemical device 1 according to a first embodiment. [Figure 1B] FIG. 1B is a side cross-sectional view (yz plane) that schematically shows the electrochemical device 1 according to the first embodiment. [Figure 2A] FIG. 2A is a horizontal cross-sectional view (Z1-Z1 portion in FIG. 1A) that schematically shows the electrochemical device 1 according to the first embodiment. [Figure 2B] FIG. 2B is a horizontal cross-sectional view (Z2-Z2 portion in FIG. 1A) showing a schematic view of the electrochemical device 1 according to the first embodiment. [Figure 3A] FIG. 3A is a horizontal cross-sectional view (Z3-Z3 portion in FIG. 1A) that schematically shows the electrochemical device 1 according to the first embodiment. [Figure 3B] FIG. 3B is a horizontal cross-sectional view (Z4-Z4 portion in FIG. 1A) that schematically shows the electrochemical device 1 according to the first embodiment. [Figure 4A] 4A and 4B are horizontal cross-sectional views (Z5-Z5 portion in FIG. 1A) that schematically show the electrochemical device 1 according to the first embodiment. [Figure 4B] 4A and 4B are horizontal cross-sectional views (Z6-Z6 portion in FIG. 1A) that schematically show the electrochemical device 1 according to the first embodiment. [Figure 5A] FIG. 5A is a side cross-sectional view that schematically shows a main part of the electrochemical device 1 according to the first embodiment (area AA in FIG. 1A). [Figure 5B] FIG. 5B is a side cross-sectional view schematically showing a main part of an electrochemical device according to Modification 1-1 of the first embodiment. [Figure 5C] FIG. 5C is a side cross-sectional view schematically showing a main part of an electrochemical device according to Modification 1-2 of the first embodiment. [Figure 5D] FIG. 5D is a side cross-sectional view schematically showing a main part of an electrochemical device according to Modification 1-3 of the first embodiment. [Figure 5E] FIG. 5E is a side cross-sectional view schematically showing a main part of an electrochemical device according to Modification 1-4 of the first embodiment. [Figure 5F] FIG. 5F is a side cross-sectional view schematically showing a main part of an electrochemical device according to Modification 1-5 of the first embodiment. [Figure 6A] FIG. 6A is a horizontal cross-sectional view (similar to FIG. 3A) that schematically shows an electrochemical device according to a second embodiment. [Figure 6B] FIG. 6B is a horizontal cross-sectional view (similar to FIG. 3B) that schematically shows the electrochemical device according to the second embodiment. [Figure 7A] FIG. 7A is a horizontal cross-sectional view (similar to FIG. 4A) that schematically shows an electrochemical device according to a second embodiment. [Figure 7B]FIG. 7B is a horizontal cross-sectional view (similar to FIG. 4B) that schematically shows the electrochemical device according to the second embodiment. [Figure 7C] FIG. 7C is a side cross-sectional view (taken along X2-X2 in FIG. 7B) that schematically shows a main part of the electrochemical device according to the second embodiment. [Figure 8A] FIG. 8A is a horizontal cross-sectional view (similar to FIG. 7A) that schematically shows an electrochemical device according to a third embodiment. [Figure 8B] FIG. 8B is a horizontal cross-sectional view (similar to FIG. 7B) that schematically shows the electrochemical device according to the third embodiment. [Figure 9A] FIG. 9A is a horizontal cross-sectional view (similar to FIG. 4A) that schematically shows an electrochemical device according to a fourth embodiment. [Figure 9B] FIG. 9B is a horizontal cross-sectional view (similar to FIG. 4B) that schematically shows the electrochemical device according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] First Embodiment [A] Configuration of electrochemical device 1 1A and 1B are side cross-sectional views schematically showing the electrochemical device 1 according to the first embodiment. FIGS. 2A, 2B, 3A, 3B, 4A, and 4B are horizontal cross-sectional views schematically showing the electrochemical device 1 according to the first embodiment. FIG. 5A is a side cross-sectional view schematically showing a main part of the electrochemical device 1 according to the first embodiment.

[0014] In FIG. 1A, the longitudinal direction is the vertical direction z, the horizontal direction is the first horizontal direction x perpendicular to the vertical direction z, and the direction perpendicular to the paper surface is the second horizontal direction y perpendicular to the vertical direction z and the first horizontal direction x. In FIG. 1B, the longitudinal direction is the vertical direction z, the horizontal direction is the second horizontal direction y, and the direction perpendicular to the paper surface is the first horizontal direction x. FIG. 1A shows a plane (xz plane) defined by the vertical direction z and the first horizontal direction x. FIG. 1B shows a plane (yz plane) defined by the vertical direction z and the second horizontal direction y.

[0015] Each of Figures 2A, 2B, 3A, 3B, 4A, and 4B illustrates a plane (xy plane) defined by a first horizontal direction x and a second horizontal direction y. Here, Figure 2A illustrates the Z1-Z1 portion of Figure 1A, and Figure 2B illustrates the Z2-Z2 portion of Figure 1A. Figure 3A illustrates the Z3-Z3 portion of Figure 1A, and Figure 3B illustrates the Z4-Z4 portion of Figure 1A. Figure 4A illustrates the Z5-Z5 portion of Figure 1A, and Figure 4B illustrates the Z6-Z6 portion of Figure 1A. Figure 5A illustrates an enlarged view of the area AA enclosed by a dashed line in Figure 1A. Figure 1A corresponds to the Y1-Y1 portion of Figure 2A, and Figure 1B corresponds to the X1-X1 portion of Figure 2A.

[0016] 1A and 1B, the electrochemical device 1 includes electrochemical cells 11a and 11b, separators 13a, 13b, and 13c, insulating sealants 14a and 14b, an insulating material 15, a gasket 16, and an insulating film 20, and is provided with a cell stack 30 in which these components are stacked in a stacking direction (here, the vertical direction z). The electrochemical device 1 further includes a pair of end plates 12a and 12b, which are disposed so as to sandwich the cell stack 30 in the stacking direction. The pair of end plates 12a and 12b are fastened together in the stacking direction using fastening members 17.

[0017] The electrochemical device 1 is also provided with a hydrogen electrode gas supply flow path FG11, a hydrogen electrode gas discharge flow path FG12, an oxygen electrode gas supply flow path FG21, and an oxygen electrode gas discharge flow path FG22. The hydrogen electrode gas supply flow path FG11 includes a plurality of hydrogen electrode gas supply ports FG11a-FG11g. The hydrogen electrode gas discharge flow path FG12 includes a plurality of hydrogen electrode gas discharge ports FG12a-FG12g. The oxygen electrode gas supply flow path FG21 includes a plurality of oxygen electrode gas supply ports FG21a-FG21g. The oxygen electrode gas discharge flow path FG22 includes a plurality of oxygen electrode gas discharge ports FG22a-FG22g.

[0018] The electrochemical device 1 is configured so that a hydrogen electrode gas G1 (first electrode gas) is supplied to the electrochemical cells 11a, 11b via a hydrogen electrode gas supply flow path FG11 and is discharged from the electrochemical cells 11a, 11b via a hydrogen electrode gas discharge flow path FG12. At the same time, the electrochemical device 1 is configured so that an oxygen electrode gas G2 (second electrode gas) is supplied to the electrochemical cells 11a, 11b via an oxygen electrode gas supply flow path FG21 and is discharged from the electrochemical cells 11a, 11b via an oxygen electrode gas discharge flow path FG22.

[0019] Although the present embodiment illustrates an example in which the stacking direction is the vertical direction z, the stacking direction may be a direction other than the vertical direction z. Furthermore, the numbers of electrochemical cells 11a, 11b, separators 13a, 13b, 13c, and insulating sealants 14a, 14b are not limited to those shown. The hydrogen electrode gas supply flow path FG11 and the hydrogen electrode gas discharge flow path FG12, and the oxygen electrode gas supply flow path FG21 and the oxygen electrode gas discharge flow path FG22 are arranged symmetrically in a plane perpendicular to the stacking direction, but they may also be arranged asymmetrically.

[0020] The details of each component of the electrochemical device 1 will be explained below in order.

[0021] [A-1] Electrochemical cells 11a and 11b Each of the multiple electrochemical cells 11a, 11b is, for example, a rectangular flat plate and includes an electrolyte membrane 110, a hydrogen electrode 111, and an oxygen electrode 112, with the electrolyte membrane 110 interposed between the hydrogen electrode 111 and the oxygen electrode 112 (see Figures 1A and 1B).

[0022] Here, each of the multiple electrochemical cells 11a, 11b is, for example, a hydrogen electrode-supported type (fuel electrode-supported type) in which an electrolyte membrane 110 and an oxygen electrode 112 are sequentially stacked on the upper surface of a hydrogen electrode 111 that functions as a support. Each of the multiple electrochemical cells 11a, 11b may have the hydrogen electrode 111 and the oxygen electrode 112 reversed in position, or may have a shape other than a square (such as a circle).

[0023] In each of the electrochemical cells 11a and 11b, the electrolyte membrane 110 is formed of oxide ions (O 2- The electrolyte membrane 110 is made of an ion-conductive solid oxide (e.g., yttria-stabilized zirconia (YSZ)) that is permeable to oxygen. The electrolyte membrane 110 is configured to be denser than the hydrogen electrode 111 and the oxygen electrode 112. The hydrogen 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).

[0024] [A-2] Multiple separators 13a, 13b, 13c Each of the separators 13a, 13b, and 13c has, for example, a rectangular flat plate shape and is made of a metal material. Here, the separators 13a, 13b, and 13c are made of a metal material that is conductive at the operating temperature of the electrochemical cells 11a and 11b (for example, 600°C to 1000°C). For example, the separators 13a, 13b, and 13c are made of a stainless steel material that has high heat resistance. Each of the separators 13a, 13b, and 13c has a thickness of, for example, 1 mm to 30 mm.

[0025] In the cell stack 30, the plurality of separators 13a, 13b, and 13c are arranged to sandwich the plurality of electrochemical cells 11a and 11b, respectively.

[0026] Although not shown, in the cell stack 30, current collectors (not shown) are interposed between each of the electrochemical cells 11a, 11b and each of the separators 13a, 13b, and 13c, and the electrochemical cells 11a, 11b are electrically connected in series by the current collectors (not shown) and the separators 13a, 13b, and 13c. The current collectors between the separator 13a and the electrochemical cell 11a and between the separator 13b and the electrochemical cell 11b are preferably made of a conductive material with excellent oxidation resistance. Furthermore, the current collectors between the separator 13b and the electrochemical cell 11a and between the separator 13c and the electrochemical cell 11b are preferably made of a conductive material such as nickel. The current collectors may be omitted depending on the state of electrical connection between each of the electrochemical cells 11a, 11b and each of the separators 13a, 13b, 13c.

[0027] The separator 13a and the separator 13c are arranged so as to be electrically connected to the bus bar B13a and the bus bar B13c, respectively.

[0028] [A-2-1] Separator 13a Of the multiple separators 13a, 13b, and 13c, the separator 13a (metal member, first separator) is placed on the oxygen electrode 112 side of the electrochemical cell 11a (see FIGS. 1A and 1B).

[0029] The separator 13a has a hydrogen electrode gas supply port FG11d and a hydrogen electrode gas discharge port FG12d formed as separator gas channels (metal member gas channels). The hydrogen electrode gas supply port FG11d and the hydrogen electrode gas discharge port FG12d penetrate the separator 13a in the stacking direction (see FIG. 1A).

[0030] The separator 13a is also provided with an electrode gas supply port FG21d and an electrode gas discharge port FG22d as separator gas channels (metallic member gas channels). The electrode gas supply port FG21d and the electrode gas discharge port FG22d penetrate the separator 13a in the stacking direction (see FIG. 1B).

[0031] In addition, an electrode gas flow channel FG213a is formed in the portion of the separator 13a facing the electrochemical cell 11a. The electrode gas flow channel FG213a is a groove extending in a direction (y direction) perpendicular to the stacking direction. There are multiple electrode gas flow channels FG213a, and the multiple electrode gas flow channels FG213a are lined up at intervals in a direction (x direction) perpendicular to the extension direction (y direction) of the electrode gas flow channel FG213a (see FIG. 1A).

[0032] [A-2-2] Separator 13b Of the multiple separators 13a, 13b, and 13c, separator 13b (second separator) has an accommodation space SP13b. The accommodation space SP13b is formed in the center of the surface (here, the upper surface) of separator 13b that faces separator 13a. The accommodation space SP13b is a recess with a rectangular planar shape, and accommodates electrochemical cell 11a (see FIGS. 1A and 1B).

[0033] The separator 13b is also provided with a hydrogen electrode gas supply port FG11f and a hydrogen electrode gas discharge port FG12f as separator gas channels, which penetrate the separator 13b in the stacking direction (see FIG. 1A).

[0034] A hydrogen electrode gas flow channel FG113b is formed in the portion of the separator 13b facing the electrochemical cell 11a. The hydrogen electrode gas flow channel FG113b is a groove extending in a direction (x direction) perpendicular to the stacking direction. There are multiple hydrogen electrode gas flow channels FG113b, and the multiple hydrogen electrode gas flow channels FG113b are lined up at intervals in a direction (y direction) perpendicular to the extension direction (x direction) of the hydrogen electrode gas flow channel FG113b (see FIGS. 1B and 2A).

[0035] The separator 13b is also provided with an oxygen electrode gas supply port FG21f and an oxygen electrode gas discharge port FG22f as separator gas channels, which penetrate the separator 13b in the stacking direction (see FIG. 1B).

[0036] In addition, an oxygen electrode gas flow channel FG213b is formed in a portion of the separator 13b facing the electrochemical cell 11b. The oxygen electrode gas flow channel FG213b is a groove extending in a direction (y direction) perpendicular to the stacking direction. There are multiple oxygen electrode gas flow channels FG213b, and the multiple oxygen electrode gas flow channels FG213b are lined up at intervals in a direction (x direction) perpendicular to the extension direction of the oxygen electrode gas flow channel FG213b (y direction) (see FIGS. 1A and 2B).

[0037] In this embodiment, the separator 13b has a single hydrogen electrode gas inlet FG11f, a single hydrogen electrode gas outlet FG12f, a single oxygen electrode gas inlet FG21f, and a single oxygen electrode gas outlet FG22f, each of which has a circular cross section in a plane (xy plane) perpendicular to the stacking direction. The separator 13b has a single hydrogen electrode gas inlet FG11f, a single hydrogen electrode gas outlet FG12f, a single oxygen electrode gas inlet FG21f, and a single oxygen electrode gas outlet FG22f, each of which is arranged concentrically in a plane (xy plane) perpendicular to the stacking direction (see FIGS. 2A and 2B).

[0038] Although not shown in the figure, in separator 13a, hydrogen electrode gas supply port portion FG11d, hydrogen electrode gas discharge port portion FG12d, oxygen electrode gas supply port portion FG21d, and oxygen electrode gas discharge port portion FG22d are each formed in the same manner as hydrogen electrode gas supply port portion FG11f, hydrogen electrode gas discharge port portion FG12f, oxygen electrode gas supply port portion FG21f, and oxygen electrode gas discharge port portion FG22f, respectively.

[0039] [A-2-3] Separator 13c Of the multiple separators 13a, 13b, and 13c, separator 13c has an accommodation space SP13c. The accommodation space SP13c is formed in the center of the surface (here, the top surface) of separator 13c that faces separator 13b. The accommodation space SP13c is a recess with a rectangular planar shape, and accommodates electrochemical cell 11b (see FIGS. 1A and 1B).

[0040] A hydrogen electrode gas flow channel FG113c is formed in the portion of the separator 13c facing the electrochemical cell 11b. The hydrogen electrode gas flow channel FG113c is a groove extending in a direction (x direction) perpendicular to the stacking direction. There are multiple hydrogen electrode gas flow channels FG113c, and the multiple hydrogen electrode gas flow channels FG113c are lined up at intervals in a direction (y direction) perpendicular to the extension direction (x direction) of the hydrogen electrode gas flow channel FG113c (see FIG. 1B).

[0041] [A-3] Multiple insulating seal materials 14a, 14b Each of the insulating seal materials 14a, 14b is interposed between each of the separators 13a, 13b, 13c in the cell stack 30 (see FIGS. 1A and 1B). Each of the insulating seal materials 14a, 14b is made of an insulating material such as a mineral such as mica or vermiculite. Alternatively, each of the insulating seal materials 14a, 14b may be made of a metal plate on which an insulating layer is laminated.

[0042] [A-3-1] Insulating sealant 14a Of the plurality of insulating seal materials 14a and 14b, the insulating seal material 14a seals the gap between the separator 13a and the separator 13b, and also electrically insulates the gap between the separator 13a and the separator 13b.

[0043] The insulating sealant 14a has, for example, a rectangular frame shape with an opening K14a formed in the center. The opening K14a of the insulating sealant 14a is located between the oxygen electrode gas flow path 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 smaller planar shape than the separator 13b, but it may have the same shape as the separator 13b (see FIGS. 1A, 1B, and 3A).

[0044] The insulating sealant 14a is provided with a hydrogen electrode gas inlet portion FG11e, a hydrogen electrode gas outlet portion FG12e, an oxygen electrode gas inlet portion FG21e, and an oxygen electrode gas outlet portion FG22e around the opening K14a. In the insulating sealant 14a, the hydrogen electrode gas inlet portion FG11e, the hydrogen electrode gas outlet portion FG12e, the oxygen electrode gas inlet portion FG21e, and the oxygen electrode gas outlet portion FG22e are each singular and have a rectangular cross section in a plane (xy plane) perpendicular to the stacking direction (see FIG. 3A).

[0045] The electrode gas supply port FG11e is located between the electrode gas supply port FG11d of the separator 13a and the storage space SP13b of the separator 13b in the stacking direction. The electrode gas discharge port FG12e is located between the electrode gas discharge port FG12d of the separator 13a and the storage space SP13b of the separator 13b in the stacking direction (see FIG. 1A).

[0046] The electrode gas supply port FG21e is located between the electrode gas supply port FG21e of the separator 13a and the storage space SP13b of the separator 13b in the stacking direction. The electrode gas discharge port FG22e is located between the electrode gas discharge port FG22e of the separator 13a and the storage space SP13b of the separator 13b in the stacking direction (see FIG. 1B).

[0047] [A-3-2] Insulating sealant 14b Of the insulating seal materials 14a and 14b, the insulating seal material 14b seals the gap between the separator 13b and the separator 13c, and also electrically insulates the gap between the separator 13b and the separator 13c.

[0048] Like the insulating sealant 14a, the insulating sealant 14b has, for example, a rectangular frame shape with an opening K14b formed in the center. The opening K14b of the insulating sealant 14b is located between the oxygen electrode gas flow path FG213b of the separator 13b and the oxygen electrode 112 of the electrochemical cell 11b in the stacking direction. Here, the insulating sealant 14b has a smaller planar shape than the separator 13b, but it may have the same shape as the separator 13b (see FIGS. 1A, 1B, and 3B).

[0049] The insulating sealant 14b is provided with a hydrogen electrode gas inlet portion FG11g, a hydrogen electrode gas outlet portion FG12g, an oxygen electrode gas inlet portion FG21g, and an oxygen electrode gas outlet portion FG22g around the opening K14b. In the insulating sealant 14b, each of the hydrogen electrode gas inlet portion FG11g, the hydrogen electrode gas outlet portion FG12g, the oxygen electrode gas inlet portion FG21g, and the oxygen electrode gas outlet portion FG22g is singular and has a rectangular cross section in a plane (xy plane) perpendicular to the stacking direction (see FIG. 3B).

[0050] The electrode gas supply port FG11g is located between the electrode gas supply port FG11f of the separator 13b and the storage space SP13c of the separator 13c in the stacking direction. The electrode gas discharge port FG12g is located between the electrode gas discharge port FG12f of the separator 13b and the storage space SP13c of the separator 13c in the stacking direction (see FIG. 1A).

[0051] The electrode gas supply port FG21g is located between the electrode gas supply port FG21f of the separator 13b and the storage space SP13c of the separator 13c in the stacking direction. The electrode gas discharge port FG22g is located between the electrode gas discharge port FG22f of the separator 13b and the storage space SP13c of the separator 13c in the stacking direction (see FIG. 1B).

[0052] [A-4] A pair of end plates 12a, 12b The pair of end plates 12a, 12b are arranged to sandwich the cell stack 30 in the stacking direction (see FIGS. 1A and 1B). Each of the pair of end plates 12a, 12b is, for example, a rectangular flat plate and is made of a metal material such as stainless steel that has high heat resistance. Each of the pair of end plates 12a, 12b has a thickness of, for example, 1 mm to 30 mm.

[0053] [A-4-1] End plate 12a Of the pair of end plates 12a, 12b, end plate 12a (first end plate) is disposed adjacent to separator 13a with a gap therebetween in the stacking direction (see FIGS. 1A and 1B).

[0054] The end plate 12a has a hydrogen electrode gas supply port FG11a and a hydrogen electrode gas discharge port FG12a formed as end plate gas channels. The hydrogen electrode gas supply port FG11a and the hydrogen electrode gas discharge port FG12a penetrate the end plate 12a in the stacking direction (see FIG. 1A). The end plate 12a also has an oxygen electrode gas supply port FG21a and an oxygen electrode gas discharge port FG22a formed as end plate gas channels. The oxygen electrode gas supply port FG21a and the oxygen electrode gas discharge port FG22a penetrate the end plate 12a in the stacking direction (see FIG. 1B).

[0055] In this embodiment, the end plate 12a has a single hydrogen electrode gas inlet FG11a, a single hydrogen electrode gas outlet FG12a, a single oxygen electrode gas inlet FG21a, and a single oxygen electrode gas outlet FG22a, each of which has a circular cross section in a plane (xy plane) perpendicular to the stacking direction. The end plate 12a has a single hydrogen electrode gas inlet FG11a, a single hydrogen electrode gas outlet FG12a, a single oxygen electrode gas inlet FG21a, and a single oxygen electrode gas outlet FG22a, each of which is arranged concentrically in a plane (xy plane) perpendicular to the stacking direction (see FIG. 4B).

[0056] A hydrogen electrode gas supply pipe H11, a hydrogen electrode gas discharge pipe H12, an oxygen electrode gas supply pipe H21, and an oxygen electrode gas discharge pipe H22 are installed on the surface of the end plate 12a opposite to the side on which the separator 13a is located (the upper surface in FIGS. 1A and 1B). The hydrogen electrode gas supply pipe H11 is connected to a hydrogen electrode gas supply port FG11a. The hydrogen electrode gas discharge pipe H12 is connected to a hydrogen electrode gas discharge port FG12a. The oxygen electrode gas supply pipe H21 is connected to an oxygen electrode gas supply port FG21a. The oxygen electrode gas discharge pipe H22 is connected to an oxygen electrode gas discharge port FG22a. In this embodiment, the hydrogen electrode gas supply pipe H11, the hydrogen 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 so that the tube axis is aligned with the stacking direction (see Figures 1A and 1B).

[0057] [A-4-2] End plate 12b Of the pair of end plates 12a, 12b, end plate 12b (second end plate) is disposed adjacent to separator 13c with a gap therebetween in the stacking direction (see FIGS. 1A and 1B).

[0058] [A-5] Insulation material 15 Insulator 15 is provided on the surface of separator 13c opposite to the surface on which electrochemical cell 11b is provided (the lower surface of separator 13c in FIGS. 1A and 1B) in cell stack 30. That is, insulator 15 is interposed between separator 13c and end plate 12b in the stacking direction.

[0059] The insulating material 15 is, for example, a rectangular plate-like body, and is made of an insulating material made of minerals such as mica or vermiculite.

[0060] [A-6] Insulating film 20 The insulating film 20 is provided on the surface (first surface; in FIGS. 1A and 1B, the top surface of the separator 13a) opposite to the surface on which the electrochemical cells 11a are provided of the separator 13a in the cell stack 30. That is, the insulating film 20 is interposed between the separator 13a and the end plate 12a in the stacking direction.

[0061] In this embodiment, the insulating film 20 is formed on the separator 13a. The insulating film 20 is formed using at least one of an oxide (alumina, silica, zirconia, stabilized zirconia, etc.) and a nitride. The insulating film 20 is formed by a film formation method such as sputtering, chemical vapor deposition, or coating, so as to have a thickness of, for example, 10 nm to 10 μm, and may be a single layer or a laminate in which multiple layers are stacked. Furthermore, it is desirable that the average surface roughness Ra of the insulating film 20 is 1 μm or less.

[0062] The insulating film 20 has a hydrogen electrode gas supply port FG11c and a hydrogen electrode gas discharge port FG12c formed therein. The hydrogen electrode gas supply port FG11c and the hydrogen electrode gas discharge port FG12c penetrate the insulating film 20 in the stacking direction (see FIG. 1A). The insulating film 20 also has an oxygen electrode gas supply port FG21c and an oxygen electrode gas discharge port FG22c formed therein. The oxygen electrode gas supply port FG21c and the oxygen electrode gas discharge port FG22c penetrate the insulating film 20 in the stacking direction (see FIG. 1B).

[0063] In this embodiment, the hydrogen electrode gas inlet portion FG11c, the hydrogen electrode gas outlet portion FG12c, the oxygen electrode gas inlet portion FG21c, and the oxygen electrode gas outlet portion FG22c are each singular and have a circular cross section in a plane (xy plane) perpendicular to the stacking direction in the insulating film 20. In the insulating film 20, the hydrogen electrode gas inlet portion FG11c, the hydrogen electrode gas outlet portion FG12c, the oxygen electrode gas inlet portion FG21c, and the oxygen electrode gas outlet portion FG22c are each formed to be aligned concentrically in a plane (xy plane) perpendicular to the stacking direction (see FIG. 4A).

[0064] [A-7] Gasket 16 The gasket 16 is provided on the surface of the insulating film 20 opposite to the surface on which the electrochemical cells 11a are provided (on the upper surface of the insulating film 20 in FIGS. 1A and 1B) in the cell stack 30. In other words, the gasket 16 is interposed between the insulating film 20 and the end plate 12a in the stacking direction, forming a manifold.

[0065] The gasket 16 is, for example, a hollow O-ring made of a metal material with high heat resistance. The gasket 16 is formed, for example, by coating the surface of a stainless steel material with a material such as gold, silver, or nickel. In addition to a hollow O-ring, the gasket 16 is preferably a flat plate, a solid O-ring, or a solid C-ring.

[0066] There are multiple gaskets 16, and each of the multiple gaskets 16 is provided at the hydrogen electrode gas supply port portions FG11a, FG11c, the hydrogen electrode gas discharge port portions FG12a, FG12c, the oxygen electrode gas supply port portions FG21a, FG21c, and the oxygen electrode gas discharge port portions FG22a, FG22c (see Figures 1A, 1B, 4A, 4B, and 5A).

[0067] Each of the gaskets 16 has a hydrogen electrode gas inlet portion FG11b, a hydrogen electrode gas outlet portion FG12b, an oxygen electrode gas inlet portion FG21b, and an oxygen electrode gas outlet portion FG22b. The central opening of each of the gaskets 16 functions as the hydrogen electrode gas inlet portion FG11b, the hydrogen electrode gas outlet portion FG12b, the oxygen electrode gas inlet portion FG21b, and the oxygen electrode gas outlet portion FG22b. The hydrogen electrode gas inlet portion FG11b, the hydrogen electrode gas outlet portion FG12b, the oxygen electrode gas inlet portion FG21b, and the oxygen electrode gas outlet portion FG22b each have a circular cross section in a plane (xy plane) perpendicular to the stacking direction (see FIGS. 1A, 1B, 4A, 4B, and 5A).

[0068] Here, gasket 16 having hydrogen electrode gas supply port FG11b is installed to seal between hydrogen electrode gas supply port FG11a of end plate 12a and hydrogen electrode gas supply port FG11c of insulating film 20 (see FIGS. 1A and 5A). Gasket 16 having hydrogen electrode gas outlet port FG12b is installed to seal between hydrogen electrode gas outlet port FG12a of end plate 12a and hydrogen electrode gas outlet port FG12c of insulating film 20 (see FIG. 1A).

[0069] The gasket 16 having the oxygen electrode gas supply port FG21b is provided to seal the gap between the oxygen electrode gas supply port FG21a of the end plate 12a and the oxygen electrode gas supply port FG21c of the insulating film 20. The gasket 16 having the oxygen electrode gas outlet port FG22b is provided to seal the gap between the oxygen electrode gas outlet port FG22a of the end plate 12a and the oxygen electrode gas outlet port FG22c of the insulating film 20 (see FIG. 1B).

[0070] [A-8] Fastening member 17 The fastening members 17 are, for example, bolts or nuts, and are fastened by inserting the shanks of the bolts into bolt holes that penetrate each part constituting the electrochemical device 1 in the stacking direction. There are multiple bolt holes, and the multiple bolt holes are formed, for example, in the periphery of each part. Alternatively, fastening may be performed by pressing the pair of end plates 12a, 12b between them using a press mechanism.

[0071] [B] Operation of electrochemical device 1 The operation of the electrochemical device 1 will be described below. Here, the case where the electrochemical cells 11a and 11b constituting the electrochemical device 1 are used as SOFCs will be described.

[0072] When the electrochemical cells 11a and 11b are used as SOFCs, in a high-temperature environment, a hydrogen electrode gas G1 containing, for example, hydrogen as a fuel gas is supplied to the hydrogen electrode 111 constituting the electrochemical cells 11a and 11b, and an oxygen electrode gas G2 containing, for example, oxygen (air) as an oxidizing gas is supplied to the oxygen electrode 112 constituting the electrochemical cells 11a and 11b (see Figures 1A and 1B).

[0073] Specifically, the hydrogen electrode gas G1 is introduced from the hydrogen electrode gas supply pipe H11 into the hydrogen electrode gas supply flow path FG11. In the hydrogen electrode gas supply flow path FG11, the hydrogen electrode gas G1 flows sequentially through a plurality of hydrogen electrode gas supply ports FG11a, FG11b, FG11c, FG11d, and FG11e, and then is introduced into the containing space SP13b of the separator 13b and supplied to the hydrogen electrode 111 of the electrochemical cell 11a via the hydrogen electrode gas flow path FG113b. In addition, in the hydrogen electrode gas supply flow path FG11, the hydrogen electrode gas G1 flows sequentially through multiple hydrogen electrode gas supply ports FG11a, FG11b, FG11c, FG11d, FG11e, FG11f, and FG11g, and is then introduced into the storage space SP13b of the separator 13b and supplied to the hydrogen electrode 111 of the electrochemical cell 11b via the hydrogen electrode gas flow path FG113c (see Figure 1A).

[0074] The electrode gas G2 is introduced from the electrode gas supply pipe H21 into the electrode gas supply flow path FG21. In the electrode gas supply flow path FG21, the electrode gas G2 flows sequentially through a plurality of electrode gas supply ports FG21a, FG21b, FG21c, and FG21d, and is then supplied to the electrode 112 of the electrochemical cell 11a via the electrode gas flow path FG213a. In the electrode gas supply flow path FG21, the electrode gas G2 flows sequentially through a plurality of electrode gas supply ports FG21a, FG21b, FG21c, FG21d, FG21e, and FG21f, and is then supplied to the electrode 112 of the electrochemical cell 11b via the electrode gas flow path FG213b (see FIG. 1B).

[0075] As a result, in each of the electrochemical cells 11a and 11b, oxygen (O 2 ) receives electrons at the oxygen electrode 112 to generate oxide ions (O 2- ) is generated. Then, the oxide ions (O 2- ) moves from the oxygen electrode 112 side to the hydrogen electrode 111 side in the electrolyte membrane 110. At the hydrogen 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- ) moves from the hydrogen electrode 111 to the oxygen electrode 112 via an external load. In this way, power is generated in each of the plurality of electrochemical cells 11a, 11b. The power generated in each of the plurality of electrochemical cells 11a, 11b is output via bus bar B 13a and bus bar B 13c (see FIGS. 1A and 1B).

[0076] Thereafter, in each of the electrochemical cells 11a and 11b, the hydrogen electrode gas G1 flows from the hydrogen electrode 111 through the hydrogen electrode gas discharge flow path FG12 to the hydrogen electrode gas discharge pipe H12 and is then discharged to the outside. At the same time, in each of the electrochemical cells 11a and 11b, the oxygen electrode gas G2 flows from the oxygen electrode 112 through the oxygen electrode gas discharge flow path FG22 to the oxygen electrode gas discharge pipe H22 and is then discharged to the outside.

[0077] Specifically, the hydrogen electrode gas G1 flows from the electrochemical cell 11a to the storage space SP13b of the separator 13b, then flows sequentially through the multiple hydrogen electrode gas outlets FG12e, FG12d, FG12c, FG12b, and FG12a in the hydrogen electrode gas discharge flow path FG12, and is discharged from the hydrogen electrode gas discharge pipe H12. Also, the hydrogen electrode gas G1 flows from the electrochemical cell 11b to the storage space SP13c of the separator 13c, then flows sequentially through the multiple hydrogen electrode gas outlets FG12g, FG12f, FG12e, FG12d, FG12c, FG12b, and FG12a in the hydrogen electrode gas discharge flow path FG12, and is discharged from the hydrogen electrode gas discharge pipe H12 (see FIG. 1A).

[0078] The electrode gas G2 flows from the electrochemical cell 11a to the accommodation space SP13b of the separator 13b, then flows sequentially through the electrode gas outlet portions FG22e, FG22d, FG22c, FG22b, and FG22a in the electrode gas discharge flow path FG22, and is discharged from the electrode gas discharge pipe H22. The electrode gas G2 flows from the electrochemical cell 11b to the accommodation space SP13c of the separator 13c, then flows sequentially through the electrode gas outlet portions FG22g, FG22f, FG22e, FG22d, FG22c, FG22b, and FG22a in the electrode gas discharge flow path FG22, and is discharged from the electrode gas discharge pipe H22 (see FIG. 1B).

[0079] As already explained, the electrochemical device 1 can use each of the plurality of electrochemical cells 11a, 11b as an SOEC, in addition to using each of the plurality of electrochemical cells 11a, 11b as an SOFC. When each of the plurality of electrochemical cells 11a, 11b is used as an SOEC, for example, hydrogen electrode gas G1 containing water vapor is supplied to the hydrogen electrode 111, and the water vapor is electrolyzed to generate hydrogen at the hydrogen electrode 111 and oxygen at the oxygen electrode 112. When electrolysis is performed, power is supplied to each of the plurality of electrochemical cells 11a, 11b via bus bar B 13a and bus bar B 13c (see FIGS. 1A and 1B).

[0080] [C] Summary As described above, in the electrochemical device 1 of this embodiment, as shown in FIGS. 1A and 5A, the end plate 12a (first end plate) is provided with a hydrogen electrode gas supply port FG11a (end plate gas flow channel). The separator 13a (first separator) is provided with a hydrogen electrode gas supply port FG11d (separator gas flow channel) that communicates with the hydrogen electrode gas supply port FG11a (end plate gas flow channel). A gasket 16 is disposed between the end plate 12a and the separator 13a. The surface (first surface) of the separator 13a that faces the end plate 12a in the stacking direction is covered with an insulating film 20.

[0081] 1A, in the electrochemical device 1 of this embodiment, the portion where the hydrogen electrode gas outlet FG12a of the end plate 12a and the hydrogen electrode gas outlet FG12d of the separator 13a are provided is configured similarly to the portion where the hydrogen electrode gas supply port FG11a and the hydrogen electrode gas supply port FG11d are provided. As shown in FIG. 1B, the portion where the oxygen electrode gas supply port FG21a of the end plate 12a and the oxygen electrode gas supply port FG21d of the separator 13a are provided is similar to the portion where the oxygen electrode gas outlet FG22a of the end plate 12a and the oxygen electrode gas outlet FG22d of the separator 13a are provided.

[0082] In the electrochemical device 1 of this embodiment, the gasket 16 is made of a metal material. Therefore, when the pair of end plates 12a, 12b are clamped in the stacking direction, the gasket 16 is crushed and deformed, thereby forming tight contact between the end plate 12a and the gasket 16, and between the gasket 16 and the separator 13a. As a result, in this embodiment, the sealing characteristics are improved, making it possible to effectively prevent leakage of the hydrogen electrode gas G1 and the oxygen electrode gas G2.

[0083] In the electrochemical device 1 of this embodiment, the end plate 12a, the gasket 16, and the separator 13a are made of metallic materials and are electrically conductive, so there is a possibility of a short circuit occurring when they are electrically connected to one another. However, in this embodiment, an insulating film 20 is formed to cover the surface (first surface) of the separator 13a that faces the end plate 12a in the stacking direction. The insulating film 20 is interposed between the gasket 16 and the separator 13a. Therefore, in this embodiment, the gasket 16 and the end plate 12a are electrically insulated from the separator 13a. As a result, the electrochemical device 1 of this embodiment can be insulated from the outside except for the bus bar B 13a and the bus bar B 13c.

[0084] Therefore, according to the electrochemical device 1 of this embodiment, the insulating properties and sealing properties are improved, and therefore it is possible to easily achieve improvements in power generation performance and electrolysis performance. If an insulating treatment is performed by covering the surface of the gasket 16 made of a metal material with an insulating film (not shown), deformation of the gasket 16 may cause the insulating film (not shown) to come off from the surface of the gasket 16, resulting in insufficient insulating properties and sealing properties.

[0085] In the electrochemical device 1 of this embodiment, the gasket 16 is a hollow O-ring made of a metal material, as described above. Therefore, when the pair of end plates 12a, 12b are fastened in the stacking direction, the gasket 16 is easily deformed, which makes it easy to improve sealing properties. The same effect can be obtained if the gasket 16 is a flat plate, a solid O-ring, or a solid C-ring, in addition to being a hollow O-ring.

[0086] In the electrochemical device 1 of this embodiment, the insulating film 20 is made of a film formed of an oxide or nitride. Since the insulating film 20 is not made of minerals such as mica or vermiculite, the sealing properties can be easily improved.

[0087] When the electrochemical device 1 is exposed to a high-temperature environment to generate electricity or perform electrolysis in the electrochemical cells 11a and 11b, the separators 13a, 13b, and 13c and the end plates 12a and 12b, which are made of metal, are likely to deform. Specifically, the separators 13a, 13b, and 13c and the end plates 12a and 12b warp due to thermal expansion, creating gaps between the components and increasing the likelihood of leaks.

[0088] However, in the electrochemical device 1 of this embodiment, the hydrogen electrode gas supply flow paths FG11 (FG11a to FG11g), the hydrogen electrode gas discharge flow paths FG12 (FG12a to FG12g), the oxygen electrode gas supply flow paths FG21 (FG21a to FG21g), and the oxygen electrode gas discharge flow paths FG22 (FG22a to FG22g) are each formed to be aligned concentrically in a plane perpendicular to the stacking direction. That is, the hydrogen electrode gas supply flow path FG11, the hydrogen electrode gas discharge flow path FG12, the oxygen electrode gas supply flow paths FG21, and the oxygen electrode gas discharge flow paths FG22 are each positioned at equal distances from the central axis AX of the plane perpendicular to the stacking direction. Even if the separators 13a, 13b, and 13c and the end plates 12a and 12b are warped, the heights of the parts at equal distances from the central axis AX of the plane perpendicular to the stacking direction are equal. Therefore, in this embodiment, leakage can be effectively prevented.

[0089] [D] Variation A modification of the above embodiment will now be described.

[0090] [D-1] Variation 1-1 5B is a side cross-sectional view schematically showing a main part of an electrochemical device according to Modification 1-1 of Embodiment 1. In FIG. 5B, the same parts as in FIG. 5A are shown.

[0091] As shown in FIG. 5B, in this modification, the insulating film 20 is not formed on the separator 13a, but on the end plate 12a, unlike in the above embodiment (see FIG. 5A).

[0092] Specifically, the insulating film 20 is provided on the surface of the end plate 12a that faces the separator 13a in the stacking direction (the lower surface; second surface in FIG. 5B). Therefore, in this modification, the gasket 16 is interposed between the insulating film 20 and the separator 13a in the stacking direction, forming a manifold. In this modification, the same effects as in the above embodiment can be obtained.

[0093] [D-2] Variation 1-2 5C is a side cross-sectional view schematically showing a main part of an electrochemical device according to Modification 1-2 of Embodiment 1. In FIG. 5C, the same parts as in FIG. 5A are shown.

[0094] As shown in FIG. 5C, in this modification, the insulating film 20 is not formed on the separator 13a, but on the end plate 12a, unlike in the above embodiment (see FIG. 5A).

[0095] Specifically, insulating film 20 is provided on the surface of end plate 12a opposite to the surface facing separator 13a in the stacking direction (top surface; third surface in FIG. 5C). Therefore, in this modification, gasket 16 is interposed between end plate 12a and separator 13a in the stacking direction, forming a manifold. In this modification, the same effects as in the above embodiment can be obtained.

[0096] [D-3] Variation 1-3 5D is a side cross-sectional view schematically showing a main part of an electrochemical device according to Modification 1-3 of Embodiment 1. In FIG. 5D, the same parts as in FIG. 5A are shown.

[0097] As shown in FIG. 5D, in this modification, the insulating film 20 is not formed on the separator 13a, but on the end plate 12a, unlike in the above embodiment (see FIG. 5A).

[0098] Specifically, the insulating film 20 is provided on the surface of the end plate 12a facing the separator 13a in the stacking direction (the lower surface; second surface in FIG. 5D ) and the surface opposite to that surface (the upper surface; third surface in FIG. 5D ). The insulating film 20 is also provided on the inner circumferential surface of the hydrogen electrode gas supply port FG11a formed in the end plate 12a. Although not shown, the insulating film 20 is also provided on the inner circumferential surfaces of the gas flow channels (hydrogen electrode gas outlet port FG12a, oxygen electrode gas supply port FG21a, and oxygen electrode gas outlet port FG22a) formed in the end plate 12a other than the hydrogen electrode gas supply port FG11a. Therefore, in this modification, the gasket 16 is interposed between the insulating film 20 and the separator 13a in the stacking direction, forming a manifold. This modification also achieves the same effects as the above embodiment.

[0099] [D-4] Variation 1-4 5E is a side cross-sectional view schematically showing a main part of an electrochemical device according to Modification 1-4 of Embodiment 1. In FIG. 5E, the same parts as in FIG. 5A are shown.

[0100] As shown in FIG. 5E, unlike the embodiment described above (see FIG. 5A), this modification has a recess T12a formed in the end plate 12a. The recess T12a is provided on the surface of the end plate 12a facing the separator 13a in the stacking direction (the lower surface; second surface in FIG. 5E). The recess T12a communicates with the hydrogen electrode gas supply port FG11a in the stacking direction. Although not shown, there are multiple recesses T12a, and the multiple recesses T12a are provided so as to communicate with the other gas flow channels (hydrogen electrode gas outlet port FG12a, oxygen electrode gas supply port FG21a, and oxygen electrode gas outlet port FG22a) formed in the end plate 12a other than the hydrogen electrode gas supply port FG11a. A gasket 16 is housed inside the recess T12a. Therefore, in this modification, the gasket 16 is interposed between the insulating film 20 and the end plate 12a in the stacking direction in the cell stack 30, forming a manifold. In this modification, the same effects as in the above embodiment can be obtained.

[0101] [D-5] Variation 1-5 5F is a side cross-sectional view schematically showing a main part of an electrochemical device according to Modification 1-5 of Embodiment 1. FIG. 5F shows the same parts as FIG. 5E.

[0102] 5F, in this modification, similar to the above-described modification 1-4 (see FIG. 5E), a recess T12a is formed in the end plate 12a, and the recess T12a houses a gasket 16. However, in this modification, unlike the above-described modification 1-4 (see FIG. 5E), the insulating film 20 is not formed on the separator 13a but is formed on the end plate 12a.

[0103] Specifically, the insulating film 20 is provided on the surface of the end plate 12a facing the separator 13a in the stacking direction (the lower surface; second surface in FIG. 5F ) and the surface opposite to that surface (the upper surface; third surface in FIG. 5F ). ​​The insulating film 20 is also provided on the inner surface of the recess T12a. Furthermore, the insulating film 20 is provided on the inner surface of the hydrogen electrode gas supply port FG11a formed in the end plate 12a. Although not shown, the insulating film 20 is also provided on the inner surfaces of the gas flow channels (hydrogen electrode gas outlet port FG12a, oxygen electrode gas supply port FG21a, and oxygen electrode gas outlet port FG22a) formed in the end plate 12a other than the hydrogen electrode gas supply port FG11a. Therefore, in this modification, the gasket 16 is interposed between the insulating film 20 and the separator 13a in the stacking direction, forming a manifold. This modification also achieves the same effects as the above embodiment.

[0104] As can be seen from the above embodiment and the above modified example, the insulating film 20 may be formed so as to cover at least one of the following surfaces: the surface (first surface) of the separator 13a facing the end plate 12a in the stacking direction; the surface (second surface) of the end plate 12a facing the separator 13a in the stacking direction; and the surface (third surface) of the end plate 12a located on the opposite side of the surface (second surface) facing the separator 13a in the stacking direction.

[0105] Second Embodiment [A] Configuration of electrochemical device 1 6A, 6B, 7A, and 7B are horizontal cross-sectional views schematically showing an electrochemical device according to a second embodiment, and Fig. 7C is a side cross-sectional view schematically showing a main part of the electrochemical device according to the second embodiment.

[0106] Each of Figures 6A, 6B, 7A, and 7B shows a plane (xy plane) defined by a first horizontal direction x and a second horizontal direction y. Here, Figure 6A shows a portion similar to Figure 3A, and Figure 6B shows a portion similar to Figure 3B. Figure 7A shows a portion similar to Figure 4A, and Figure 7B shows a portion similar to Figure 4B. Figure 7C corresponds to the X2-X2 portion in Figure 7B.

[0107] As shown in the drawings, the electrochemical device of this embodiment differs in part from that of the first embodiment. Other than this and related points, the electrochemical device of this embodiment is the same as that of the first embodiment. Therefore, in this embodiment, explanations of overlapping points will be omitted as appropriate.

[0108] 6A and 6B, in the separator 13b of this embodiment, each of the hydrogen electrode gas inlet portion FG11f, the hydrogen electrode gas outlet portion FG12f, the oxygen electrode gas inlet portion FG21f, and the oxygen electrode gas outlet portion FG22f is plural rather than singular, unlike in the first embodiment. Although not shown, the separator 13a also has each of the hydrogen electrode gas inlet portion FG11d, the hydrogen electrode gas outlet portion FG12d, the oxygen electrode gas inlet portion FG21d, and the oxygen electrode gas outlet portion FG22d in the same manner as the hydrogen electrode gas inlet portion FG11f, the hydrogen electrode gas outlet portion FG12f, the oxygen electrode gas inlet portion FG21f, and the oxygen electrode gas outlet portion FG22f.

[0109] 7A, the insulating film 20 has a plurality of hydrogen electrode gas inlet portions FG11c, hydrogen electrode gas outlet portions FG12c, oxygen electrode gas inlet portions FG21c, and oxygen electrode gas outlet portions FG22c, rather than a single portion, as in the separator 13b. Also, as shown in FIG. 7B, the end plate 12a has a plurality of hydrogen electrode gas inlet portions FG11a, hydrogen electrode gas outlet portions FG12a, oxygen electrode gas inlet portions FG21a, and oxygen electrode gas outlet portions FG22a, rather than a single portion, as in the separator 13b.

[0110] In this embodiment, as shown in Fig. 7B, gaskets 16 are provided at each of the multiple hydrogen electrode gas supply ports FG11a, multiple hydrogen electrode gas outlet ports FG12a, multiple oxygen electrode gas supply ports FG21a, and multiple oxygen electrode gas outlet ports FG22a formed on end plate 12a. That is, as shown in Fig. 7A, gaskets 16 are provided at each of the multiple hydrogen electrode gas supply ports FG11c, multiple hydrogen electrode gas outlet ports FG12c, multiple oxygen electrode gas supply ports FG21c, and multiple oxygen electrode gas outlet ports FG22c formed on insulating film 20.

[0111] 7B, the positions at which the hydrogen electrode gas supply pipe H11, the hydrogen electrode gas discharge pipe H12, the oxygen electrode gas supply pipe H21, and the oxygen electrode gas discharge pipe H22 are installed on the separator 13a differ from those in the first embodiment (see FIGS. 1A and 1B). In this embodiment, the hydrogen electrode gas supply pipe H11, the hydrogen electrode gas discharge pipe H12, the oxygen electrode gas supply pipe H21, and the oxygen electrode gas discharge pipe H22 are installed on the side surfaces of the end plate 12a along the stacking direction.

[0112] Specifically, the hydrogen electrode gas supply pipe H11 is installed on one of the two side surfaces of the end plate 12a that are aligned with the first horizontal direction x, and the hydrogen electrode gas discharge pipe H12 is installed on the other of the two side surfaces of the end plate 12a that are aligned with the first horizontal direction x. The oxygen electrode gas supply pipe H21 is installed on one of the two side surfaces of the end plate 12a that are aligned with the second horizontal direction y, and the oxygen electrode gas discharge pipe H22 is installed on the other of the two side surfaces of the end plate 12a that are aligned with the second horizontal direction y.

[0113] As shown in FIG. 7B, the end plate 12a of this embodiment is further formed with a hydrogen electrode gas supply communication channel FG110, a hydrogen electrode gas discharge communication channel FG120, an oxygen electrode gas supply communication channel FG210, and an oxygen electrode gas discharge communication channel FG220.

[0114] Specifically, the hydrogen electrode gas supply communication channel FG110 extends, for example, along the second horizontal direction y on the end plate 12a, and connects each of the multiple hydrogen electrode gas supply port sections FG11a to the hydrogen electrode gas supply pipe H11 (see FIG. 7C). The hydrogen electrode gas discharge communication channel FG120 extends, for example, along the second horizontal direction y on the end plate 12a, and connects each of the multiple hydrogen electrode gas discharge port sections FG12a to the hydrogen electrode gas discharge pipe H12.

[0115] The electrode gas supply communication channel FG210 extends, for example, along the first horizontal direction x on the end plate 12a, and connects each of the electrode gas supply port sections FG21a to the electrode gas supply pipe H21. The electrode gas discharge communication channel FG220 extends, for example, along the first horizontal direction x on the end plate 12a, and connects each of the electrode gas discharge port sections FG22a to the electrode gas discharge pipe H22.

[0116] [B] Summary 6A, 6B, 7A, and 7B, the electrochemical device of this embodiment is provided with a plurality of hydrogen electrode gas supply passages FG11, hydrogen electrode gas discharge passages FG12, oxygen electrode gas supply passages FG21, and oxygen electrode gas discharge passages FG22 (see FIGS. 1A and 1B). Therefore, in the electrochemical cells 11a and 11b, the hydrogen electrode gas G1 and oxygen electrode gas G2 flow more uniformly than in the first embodiment, making it easy to achieve improvements in power generation performance and electrolysis performance.

[0117] In this embodiment, the end plate 12a is formed with a hydrogen electrode gas supply communication channel FG110, a hydrogen electrode gas discharge communication channel FG120, an oxygen electrode gas supply communication channel FG210, and an oxygen electrode gas discharge communication channel FG220. The hydrogen electrode gas supply communication channel FG110 connects each of the multiple hydrogen electrode gas supply ports FG11a to the hydrogen electrode gas supply pipe H11, and the hydrogen electrode gas discharge communication channel FG120 connects each of the multiple hydrogen electrode gas discharge ports FG12a to the hydrogen electrode gas discharge pipe H12. The oxygen electrode gas supply communication channel FG210 connects each of the multiple oxygen electrode gas supply ports FG21a to the oxygen electrode gas supply pipe H21, and the oxygen electrode gas discharge communication channel FG220 connects each of the multiple oxygen electrode gas discharge ports FG22a to the oxygen electrode gas discharge pipe H22. Therefore, in this embodiment, even if there are multiple hydrogen electrode gas supply flow paths FG11, hydrogen electrode gas discharge flow paths FG12, oxygen electrode gas supply flow paths FG21, and oxygen electrode gas discharge flow paths FG22, there is no need to install multiple hydrogen electrode gas supply pipes H11, hydrogen electrode gas discharge pipes H12, oxygen electrode gas supply pipes H21, and oxygen electrode gas discharge pipes H22.

[0118] Third Embodiment [A] Configuration of electrochemical device 1 8A and 8B are horizontal cross-sectional views schematically showing an electrochemical device according to a third embodiment, in which Fig. 8A shows the same portion as Fig. 7A, and Fig. 8B shows the same portion as Fig. 7B.

[0119] As shown in the drawings, the electrochemical device of this embodiment differs in part from the second embodiment (see FIGS. 7A and 7B). Other than this and related points, the electrochemical device of this embodiment is similar to the second embodiment. Therefore, overlapping points in this embodiment will not be described again.

[0120] As shown in Figure 8B, in the electrochemical device of this embodiment, unlike the second embodiment (see Figure 7A), gaskets 16 are not provided at each of the multiple hydrogen electrode gas supply port portions FG11a, the multiple hydrogen electrode gas discharge port portions FG12a, the multiple oxygen electrode gas supply port portions FG21a, and the multiple oxygen electrode gas discharge port portions FG22a.

[0121] In this embodiment, a single gasket 16 is provided for each of the multiple hydrogen electrode gas supply ports FG11a formed on the end plate 12a (see FIG. 8B). That is, a single gasket 16 is provided for each of the multiple hydrogen electrode gas supply ports FG11c formed on the insulating film 20 (see FIG. 8A). Therefore, in this embodiment, after passing through each of the multiple hydrogen electrode gas supply ports FG11a formed on the end plate 12a, the hydrogen electrode gas G1 flows via the hydrogen electrode gas supply port FG11b of the single gasket 16 to each of the multiple hydrogen electrode gas supply ports FG11c formed on the insulating film 20.

[0122] In this embodiment, a single gasket 16 is provided for each of the multiple hydrogen electrode gas outlets FG12a formed on the end plate 12a (see FIG. 8B). That is, a single gasket 16 is provided for each of the multiple hydrogen electrode gas outlets FG12c formed on the insulating film 20 (see FIG. 8A). Therefore, in this embodiment, after passing through each of the multiple hydrogen electrode gas outlets FG12c formed on the insulating film 20, the hydrogen electrode gas G1 flows via the hydrogen electrode gas outlet FG12b of the single gasket 16 to each of the multiple hydrogen electrode gas outlets FG12a formed on the end plate 12a.

[0123] Similarly, a single gasket 16 is provided for the multiple electrode gas supply ports FG21a formed on the end plate 12a, and a single gasket 16 is provided for the multiple electrode gas discharge ports FG22a formed on the end plate 12a (see FIG. 8B). That is, a single gasket 16 is provided for the multiple electrode gas supply ports FG21c formed on the insulating film 20, and a single gasket 16 is provided for the multiple electrode gas discharge ports FG22c formed on the insulating film 20 (see FIG. 8A).

[0124] [B] Summary As described above, in the electrochemical device of this embodiment, a single gasket 16 is provided for the multiple hydrogen electrode gas supply ports FG11a (FG11c), and a single gasket 16 is provided for the multiple hydrogen electrode gas outlet ports FG12a (FG12c). A single gasket 16 is provided for the multiple oxygen electrode gas supply ports FG21a (FG21c), and a single gasket 16 is provided for the multiple oxygen electrode gas outlet ports FG22a (FG22c). Therefore, in this embodiment, the number of gaskets 16 can be reduced compared to the second embodiment, which facilitates cost reductions and the like.

[0125] <Fourth embodiment> [A] Configuration of electrochemical device 1 9A and 9B are horizontal cross-sectional views schematically showing an electrochemical device according to a fourth embodiment.

[0126] Here, FIG. 9A shows a portion similar to FIG. 4A, and FIG. 9B shows a portion similar to FIG. 4B.

[0127] As shown in the drawings, the electrochemical device of this embodiment differs in part from the first embodiment (see FIGS. 4A and 4B). Other than this and related points, the electrochemical device of this embodiment is similar to the first embodiment. Therefore, in this embodiment, explanations of overlapping points will be omitted where appropriate.

[0128] 9A, in the insulating film 20, the hydrogen electrode gas inlet portion FG11c, the hydrogen electrode gas outlet portion FG12c, the oxygen electrode gas inlet portion FG21c, and the oxygen electrode gas outlet portion FG22c each have an arc-shaped cross section in a plane (xy plane) perpendicular to the stacking direction, and are arranged side by side along a circle. The hydrogen electrode gas inlet portion FG11c, the hydrogen electrode gas outlet portion FG12c, the oxygen electrode gas inlet portion FG21c, and the oxygen electrode gas outlet portion FG22c are each provided at the same position from the central axis AX in the plane perpendicular to the stacking direction.

[0129] 9B, the end plate 12a has a hydrogen electrode gas inlet FG11a, a hydrogen electrode gas outlet FG12a, an oxygen electrode gas inlet FG21a, and an oxygen electrode gas outlet FG22a, each of which has a similar configuration. The cross section of the hydrogen electrode gas inlet FG11a, the hydrogen electrode gas outlet FG12a, the oxygen electrode gas inlet FG21a, and the oxygen electrode gas outlet FG22a in a plane perpendicular to the stacking direction (xy plane) is arc-shaped, and they are arranged side by side along a circle. The hydrogen electrode gas inlet FG11a, the hydrogen electrode gas outlet FG12a, the oxygen electrode gas inlet FG21a, and the oxygen electrode gas outlet FG22a are each located at the same position from the central axis AX in the plane perpendicular to the stacking direction.

[0130] Although not shown, the separator 13a also has a hydrogen electrode gas inlet portion FG11d, a hydrogen electrode gas outlet portion FG12d, an oxygen electrode gas inlet portion FG21d, and an oxygen electrode gas outlet portion FG22d that are similarly configured.The separator 13b also has a hydrogen electrode gas inlet portion FG11f, a hydrogen electrode gas outlet portion FG12f, an oxygen electrode gas inlet portion FG21f, and an oxygen electrode gas outlet portion FG22f that are similarly configured.

[0131] As shown in Figures 9A and 9B, in each of the multiple gaskets 16, the hydrogen electrode gas supply port portion FG11b, the hydrogen electrode gas discharge port portion FG12b, the oxygen electrode gas supply port portion FG21b, and the oxygen electrode gas discharge port portion FG22b each have an arc-shaped cross section in a plane (xy plane) perpendicular to the stacking direction.

[0132] [B] Summary As described above, in the electrochemical device of this embodiment, a gasket 16 made of a metal material is provided between the end plate 12a and the separator 13a. The surface (first surface) of the separator 13a facing the end plate 12a in the stacking direction is covered with an insulating film 20. Therefore, this embodiment can also achieve the same effects as the first embodiment.

[0133] 9A and 9B, in the electrochemical device of this embodiment, the hydrogen electrode gas supply flow path FG11, the hydrogen electrode gas discharge flow path FG12, the oxygen electrode gas supply flow path FG21, and the oxygen electrode gas discharge flow path FG22 each have an arc-shaped cross section in a plane (xy plane) perpendicular to the stacking direction. Therefore, in the electrochemical cells 11a and 11b, the hydrogen electrode gas G1 and the oxygen electrode gas G2 flow more uniformly than in the first embodiment, making it easy to achieve improvements in power generation performance and electrolysis performance.

[0134] <Other> Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

[0135] For example, in the above embodiment, as shown in Fig. 1B, the bus bar B 13a is installed on the side of the separator 13a, but the present invention is not limited to this. Although not shown, a bus bar (not shown) may be installed between the separator 13a and the end plate 12a, and a gasket 16 may be interposed between the bus bar (not shown) and the end plate 12a (see Fig. 1B). [Explanation of symbols]

[0136] 1: electrochemical device, 11a: electrochemical cell, 11b: electrochemical cell, 12a: end plate (metal member, first end plate), 12b: end plate (second end plate), 13a: separator (first separator), 13b: separator (second separator), 13c: separator, 14a: insulating seal material, 14b: insulating seal material, 15: insulating material, 16: gasket, 17: fastening member, 20: insulating film, 30: cell stack, 110: electrolyte membrane, 111: hydrogen electrode (first electrode), 112: oxygen electrode (second electrode), B13a: bus bar , B13c: busbar, FG11: hydrogen electrode gas supply passage, FG110: hydrogen electrode gas supply connection passage, FG113b: hydrogen electrode gas passage, FG113c: hydrogen electrode gas passage, FG11a: hydrogen electrode gas supply port (end plate gas passage), FG11b: hydrogen electrode gas supply port, FG11c: hydrogen electrode gas supply port, FG11d: hydrogen electrode gas supply port (metal member gas passage, separator gas passage), FG11e: hydrogen electrode gas supply port, FG11f: hydrogen electrode gas supply port, FG11g: hydrogen electrode gas supply port, FG12: hydrogen electrode gas discharge passage, FG120: water anode gas exhaust communication channel, FG12a: hydrogen electrode gas exhaust port (end plate gas flow channel), FG12b: hydrogen electrode gas exhaust port, FG12c: hydrogen electrode gas exhaust port, FG12d: hydrogen electrode gas exhaust port (metal member gas flow channel, separator gas flow channel), FG12e: hydrogen electrode gas exhaust port, FG12f: hydrogen electrode gas exhaust port, FG12g: hydrogen electrode gas exhaust port, FG21: oxygen electrode gas supply flow channel, FG210: oxygen electrode gas supply communication channel, FG213a: oxygen electrode gas flow channel, FG213b: oxygen electrode gas flow channel, FG21a: oxygen electrode gas supply port (end plate gas flow path), FG21b: oxygen electrode gas supply port, FG21c: oxygen electrode gas supply port, FG21d: oxygen electrode gas supply port (metallic member gas flow path, separator gas flow path), FG21e: oxygen electrode gas supply port, FG21f: oxygen electrode gas supply port, FG21g: oxygen electrode gas supply port, FG22: oxygen electrode gas discharge flow path, FG220: oxygen electrode gas discharge communication path, FG22a: oxygen electrode gas discharge port (end plate gas flow path), FG22b: oxygen electrode gas discharge port, FG22c: oxygen electrode gas discharge port, FG22d: oxygen electrode gas discharge port (metallic member gas flow path,separator gas flow path), FG22e: oxygen electrode gas outlet, FG22f: oxygen electrode gas outlet, FG22g: oxygen electrode gas outlet, G1: hydrogen electrode gas (first electrode gas), G2: oxygen electrode gas (second electrode gas), H11: hydrogen electrode gas supply pipe, H12: hydrogen electrode gas outlet pipe, H21: oxygen electrode gas supply pipe, H22: oxygen electrode gas outlet pipe, K14a: opening, K14b: opening, SP13b: storage space, SP13c: storage space, T12a: recess,

Claims

1. a cell stack including at least an electrochemical cell having an electrolyte membrane interposed between a first electrode and a second electrode, and a metal member formed of a metal material, the cell stack being stacked so that the electrochemical cell and the metal member are electrically connected in the stacking direction, and a first electrode gas flows through the first electrode, and a second electrode gas flows through the second electrode; a first end plate and a second end plate, which are disposed so as to sandwich the cell stack in the stacking direction and are made of a metal material; the first end plate and the metal member are arranged adjacent to each other in the stacking direction.

1. An electrochemical device comprising: the first end plate is provided with an end plate gas flow channel through which at least one of the first electrode gas and the second electrode gas flows; the metal member is provided with a metal member gas flow path that communicates with the end plate gas flow path, a gasket is provided between the first end plate and the metal member to seal the end plate gas flow path and the metal member gas flow path; The gasket is made of a metal material, an insulating film is formed to cover at least one of a first surface of the metal member facing the first end plate in the stacking direction, a second surface of the first end plate facing the metal member in the stacking direction, and a third surface of the first end plate located on the opposite side of the second surface in the stacking direction; Electrochemical equipment.

2. The gasket is any one of a flat plate, a solid O-ring, a hollow O-ring, and a solid C-ring. The electrochemical device of claim 1 .

3. the insulating film is formed using at least one of an oxide and a nitride; The electrochemical device of claim 1 .

4. the end plate gas flow passages and the metal member gas flow passages are each provided in plurality, and the plurality of end plate gas flow passages and the plurality of metal member gas flow passages are formed so as to be concentrically arranged on a plane perpendicular to the stacking direction. The electrochemical device of claim 1 .

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