Electrochemical element stack, electrochemical device, and energy system

Abstract

To provide a technique that makes it possible to uniformly transfer load in an electrochemical element stack.SOLUTION: An electrochemical element stack is formed by stacking an electrochemical reaction portion 3 to which a first gas and a second gas are supplied, a support 1 that supports the electrochemical reaction portion 3, and a separator 2 that separates a flow path for the first gas from a flow path for the second gas, all stacked together with a load applied in the stacking direction, and is provided with a flat plate-like structure 92 that is disposed between the support 1 and the separator 2 and is capable of applying a load from one of the support 1 and the separator 2 to the other.SELECTED DRAWING: Figure 14

Description

[Technical Field]

[0001] The present invention relates to an electrochemical element stack, an electrochemical device, and an energy system. [Background technology]

[0002] Patent Document 1 discloses a solid oxide fuel cell stack. This fuel cell stack includes a plurality of power generation units and a pair of end plates. Seven power generation units are arranged in a vertical line. The pair of end plates are arranged to sandwich an assembly made up of the seven power generation units from above and below. The fuel cell stack is fastened in the vertical direction with bolts and nuts. Each power generation unit includes a fuel electrode-side current collector arranged in a fuel chamber. The fuel electrode-side current collector is arranged between the fuel electrode and an interconnector. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-180295 Summary of the Invention [Problem to be solved by the invention]

[0004] In the fuel cell stack of Patent Document 1, the power generation units are fastened in the vertical direction with bolts and nuts, which applies a large force in the vertical direction. This force is transmitted from the anode to the interconnector via the anode-side current collector. The anode-side current collector disclosed in Patent Document 1 is a small member, as shown in FIG. 4, etc., so a large force is applied locally to the anode and the interconnector. This can cause various problems, such as damage to the members and non-uniformity in the flow of reactant gas due to member deformation.

[0005] An object of the present invention is to provide a technique that can make the transmission of load uniform in an electrochemical element stack. [Means for solving the problem]

[0006] The electrochemical element stack according to the present invention is characterized in that it is an electrochemical element stack in which an electrochemical reaction section to which a first gas and a second gas are supplied, a support supporting the electrochemical reaction section, and a separator separating a flow path for the first gas from a flow path for the second gas are stacked in a state in which a load is applied in the stacking direction, and the electrochemical element stack includes a flat plate-like structure disposed between the support and the separator and capable of applying a load from one of the support and the separator to the other.

[0007] According to the above-described characteristic configuration, the flat plate-like structure is disposed between the support and the separator. The flat plate-like structure is a member that extends in a flat plate shape along the support and the separator, and therefore comes into contact with the support and the separator over a wide area. Therefore, the load in the stacking direction is transmitted over a wide area, making it possible to uniformly transmit the load in the electrochemical element stack. This makes it possible to prevent problems such as damage to components and non-uniform gas flow due to component deformation.

[0008] A further characteristic feature of the electrochemical element laminate according to the present invention is that the flat plate-like structures have electrical conductivity.

[0009] According to the above characteristic configuration, the flat plate-like structure has electrical conductivity, so that a current path in the stacking direction is ensured, thereby improving the performance of the electrochemical element stack.

[0010] A further characteristic feature of the electrochemical element laminate according to the present invention is that the flat plate-like structures are made of metal.

[0011] According to the above characteristic configuration, the flat plate-like structures are made of metal, and therefore the durability of the electrochemical element stack is improved.

[0012] A further characteristic feature of the electrochemical element laminate according to the present invention is that the flat plate-like structures are made of Ni or stainless steel.

[0013] According to the above characteristic configuration, the flat plate-like structures are made of Ni or stainless steel, and therefore the flat plate-like structures have excellent electronic conductivity, heat resistance, oxidation resistance, and corrosion resistance.

[0014] A further characteristic feature of the electrochemical element laminate according to the present invention is that the flat plate-like structures are metal mesh or lath metal.

[0015] According to the above-mentioned characteristic configuration, since the flat plate-like structure is made of a metal mesh or lath metal, the flat plate-like structure is less likely to obstruct gas flow. In addition, the rigidity of the flat plate-like structure can be increased, and deformation of the flat plate-like structure due to load can be reduced. Furthermore, the flat plate-like structure can be manufactured inexpensively.

[0016] A further characteristic feature of the electrochemical element laminate according to the present invention is that the flat plate-like structures extend in the longitudinal direction up to the vicinity of the longitudinal end of the electrochemical reaction section.

[0017] According to the above characteristic configuration, the flat plate-like structure has a size approximately the same as that of the electrochemical reaction section, so deformation of the electrochemical reaction section can be suppressed, and deterioration in the performance of the electrochemical element stack can be suppressed.

[0018] A further characteristic feature of the electrochemical element laminate according to the present invention is that the thickness of the flat plate-like structure is 80% or more of the distance between the support and the separator.

[0019] According to the above characteristic configuration, the thickness of the flat plate-like structure is 80% or more of the distance between the support and the separator, thereby preventing excessive displacement of the support or the separator and maintaining the performance of the electrochemical element stack.

[0020] A further characteristic feature of the electrochemical element stack according to the present invention is that the support and the separator are plate-shaped, the support and the separator are joined together to form an internal flow path for the first gas between opposing surfaces of the support and the separator, and the flat plate-like structure is disposed in the internal flow path.

[0021] According to the above-described characteristic configuration, the flat plate-like structures transmit force in the stacking direction in addition to the joints between the support and the separator, thereby further uniforming the load transmission in the electrochemical element stack. Furthermore, since the flat plate-like structures are disposed in the internal flow paths, the flat plate-like structures suppress deformation of the internal flow paths. Therefore, deterioration of the performance of the electrochemical element due to deformation of the internal flow paths can be suppressed.

[0022] A further characteristic feature of the electrochemical element stack according to the present invention is that the internal flow path has a plurality of sub-flow paths, a distribution section that distributes gas to the sub-flow paths, and a junction section where gas from the sub-flow paths join together, the separator is formed in a corrugated shape, the peaks of the waves divide the sub-flow paths, and the longitudinal ends of the flat plate-like structure are located more inward than the longitudinal ends of the peaks.

[0023] When the separator is formed in a corrugated shape, due to processing errors, the longitudinal ends of the wave peaks may protrude beyond the remaining portions of the peaks. Therefore, in a configuration in which the longitudinal ends of the wave peaks contact the flat plate-like structure, local load concentration may occur. According to the above characteristic configuration, the longitudinal ends of the flat plate-like structure are located inside the longitudinal ends of the peaks, so the longitudinal ends of the wave peaks do not contact the flat plate-like structure. Therefore, local load concentration can be avoided.

[0024] The electrochemical device according to the present invention is characterized in that it has at least the electrochemical element stack and a fuel converter, and has a fuel supply unit that supplies reducing component gas from the fuel converter to the electrochemical element stack, or that supplies reducing component gas from the electrochemical element stack to the fuel converter.

[0025] According to the above-described characteristic configuration, it is possible to uniformly transfer load in the electrochemical element stack, thereby suppressing problems in the electrochemical device, such as damage to components and non-uniform gas flow due to component deformation.

[0026] Furthermore, according to the above-mentioned characteristic configuration, the device has at least an electrochemical element stack and a fuel converter, and a fuel supply unit that supplies a reducing component gas from the fuel converter to the electrochemical element stack or that supplies a reducing component gas from the electrochemical element stack to the fuel converter. Therefore, when the electrochemical element is operated as a fuel cell, if hydrogen is generated by a fuel converter such as a reformer from natural gas supplied using an existing raw fuel supply infrastructure such as city gas, an electrochemical device equipped with an electrochemical element that is excellent in durability, reliability, and performance can be realized. Furthermore, since it becomes easier to build a system for recycling unused fuel gas discharged from the electrochemical element, a highly efficient electrochemical device can be realized.

[0027] When the electrochemical device is operated as an electrolytic cell, gas containing water vapor and carbon dioxide is passed through the electrode layer, and a voltage is applied between the electrode layer and the counter electrode layer. Then, electrons e - reacts with water molecules H2O and carbon dioxide molecules CO2, producing hydrogen molecules H2, carbon monoxide CO, and oxygen ions O 2- Oxygen ions O 2- moves through the electrolyte layer to the counter electrode layer. In the counter electrode layer, oxygen ions O 2- releases electrons and becomes oxygen molecules O2. Through the above reaction, water molecules H2O are electrolyzed into hydrogen H2 and oxygen O2, and when gas containing carbon dioxide molecules CO2 is circulated, it is electrolyzed into carbon monoxide CO and oxygen O2. When gas containing water vapor and carbon dioxide molecules (CO2) is circulated, a fuel converter can be provided that synthesizes various compounds such as hydrocarbons from the hydrogen and carbon monoxide produced in the electrochemical element by the electrolysis. The hydrocarbons produced by this fuel converter can be circulated to the electrochemical element by a fuel supply unit, or extracted outside the system / device and used separately as fuel or chemical raw materials.

[0028] The electrochemical device according to the present invention is characterized by having at least the above-mentioned electrochemical element stack and a power converter that extracts electric power from the electrochemical element stack or passes electric power to the electrochemical element stack.

[0029] According to the above-described characteristic configuration, it is possible to uniformly transfer load in the electrochemical element stack, thereby suppressing problems in the electrochemical device, such as damage to components and non-uniform gas flow due to component deformation.

[0030] Furthermore, according to the above characteristic configuration, the power converter extracts power generated by the electrochemical device or passes power to the electrochemical device. As a result, the electrochemical device functions as a fuel cell or an electrolysis cell. Therefore, according to the above configuration, it is possible to provide an electrochemical device or the like that can improve the efficiency of converting chemical energy such as fuel into electrical energy or converting electrical energy into chemical energy such as fuel.

[0031] For example, when an inverter is used as a power converter, the inverter can boost the electrical output obtained from an electrochemical element, which has excellent durability, reliability, and performance, or convert direct current to alternating current, making it easier to utilize the electrical output obtained from the electrochemical element, which is preferable.

[0032] The energy system according to the present invention is characterized by having the electrochemical device described above and a waste heat utilization section that reuses heat discharged from the electrochemical device or the fuel converter.

[0033] According to the above characteristic configuration, since the system has an electrochemical device and a waste heat utilization unit that reuses heat discharged from the electrochemical device or the fuel converter, it is possible to realize an energy system that is excellent in durability, reliability, performance, and energy efficiency. Furthermore, it is also possible to realize a hybrid system with excellent energy efficiency by combining it with a power generation system that generates electricity by utilizing the combustion heat of unused fuel gas discharged from the electrochemical device or the fuel converter. [Brief explanation of the drawings]

[0034] [Figure 1] FIG. 1 is a cross-sectional view of an electrochemical module. [Figure 2] FIG. 2 is a top view of an electrochemical module. [Figure 3] FIG. 2 is a side view of an electrochemical module. [Figure 4] FIG. 1 is a schematic diagram of an electrochemical module. [Figure 5] FIG. 1 is a schematic diagram of an electrochemical device. [Figure 6] 6 is a cross-sectional view taken along the line VI-VI in FIG. 5. [Figure 7] FIG. 7 is a view taken along line VII-VII in FIG. 5. [Figure 8] 8 is a cross-sectional view taken along the line VIII-VIII in FIG. 5. [Figure 9] 9 is a cross-sectional view taken along line IX-IX in FIG. 5. [Figure 10] XX cross-sectional view of FIG. 5. [Figure 11] 10 is a cross-sectional view taken along the line XI-XI in FIG. 5. [Figure 12] 12 is a cross-sectional view taken along the line XII-XII in FIG. 5. [Figure 13] 13 is a cross-sectional view taken along the line XIII-XIII in FIG. 5. [Figure 14] FIG. 2 is an enlarged view of a main part of an electrochemical reaction section. [Figure 15] FIG. 2 is an exploded perspective view showing an electrochemical element laminate and a current collector. [Figure 16] FIG. 1 is a schematic diagram of an energy system. [Figure 17] FIG. 1 is a schematic diagram of another energy system. DETAILED DESCRIPTION OF THE INVENTION

[0035] [Embodiment] The following describes an electrochemical module M and an assembly method for the electrochemical module M according to an embodiment of the present invention. When describing the positional relationship of layers, for example, the electrolyte layer side as viewed from the electrode layer is referred to as "top" or "upper side," and the first plate-shaped body side is referred to as "bottom" or "lower side." Furthermore, since the same effect can be achieved in the present invention whether the electrochemical module M is installed vertically or horizontally, "top" and "bottom" can also be read as "left" and "right," respectively.

[0036] (1) Overall configuration of electrochemical module M The overall configuration of the electrochemical module M will be described below. As shown in Fig. 1, the electrochemical module M includes an electrochemical element stack (stack) S and a roughly rectangular parallelepiped container (housing, first sandwiching body, second sandwiching body) 200 that houses the electrochemical element stack S. The electrochemical element A (Fig. 4) is an element that generates electricity, and is formed in a plate shape extending from the front to the back of the paper in the cross-sectional view of Fig. 1. The electrochemical element stack S is configured by stacking a plurality of flat plate-shaped electrochemical elements A in the vertical stacking direction in the cross-sectional view of Fig. 1. In this embodiment, an SOFC (Solid Oxide Fuel Cell) will be described as an example of the electrochemical element A.

[0037] The electrochemical module M also includes a first gas supply section 61 that supplies a first gas to the electrochemical element stack S from outside the container 200, and a first gas discharge section 62 that discharges the first gas after reaction in the electrochemical element stack S.

[0038] In this embodiment, the first gas supply unit 61 is composed of an external pipe 61a that supplies the first gas, a connection member 61b, and a supply pipe member 81c (pipe member J). The first gas discharge unit 62 is composed of an external pipe 62a that discharges the second gas, a connection member 62b, and a discharge pipe member 81d (pipe member J).

[0039] As shown in FIGS. 1 to 3, the container 200 is provided with a second gas supply unit 71, which supplies a second gas from outside the container 200 to the electrochemical element stack S. The second gas produced after the reaction in the electrochemical element stack S is discharged to the outside from a second gas discharge unit 72 provided in the container 200.

[0040] Here, the first gas is a reducing gas such as a fuel gas, and the second gas is an oxidizing gas such as air.

[0041] 1, the electrochemical module M is provided with opening-equipped plate members 240 on both side surfaces of the electrochemical element stack S. The opening-equipped plate members 240 are plate-shaped members that correspond to both side surfaces of the electrochemical element stack S and extend in the stacking direction of the electrochemical elements A, and are preferably made of an insulating material such as mica or alumina to prevent electrical short circuits in the electrochemical module M. The opening-equipped plate members 240 have openings 240a formed therein that penetrate the electrochemical element stack S in the planar direction.

[0042] Thus, the electrochemical element stack S receives a supply of fuel gas from the first gas supply unit 61, a supply of air from the second gas supply unit 71 through the openings 240a of the opening-equipped plate member 240, and generates electricity by causing an electrochemical reaction between the fuel gas and oxygen in the air. The fuel gas after the electrochemical reaction is discharged to the outside from the first gas discharge unit 62. The air after the electrochemical reaction is led to the second gas discharge unit 72 through the openings 240a of the opening-equipped plate member 240 and discharged from the second gas discharge unit 72 to the outside.

[0043] Here, although aperture plate members 240 are provided adjacent to both side surfaces of the electrochemical element stack S, this is not essential, and either one may be provided, or both may be omitted.

[0044] The electrochemical module M also includes, on the top of the electrochemical element stack S, a current collector 81 and an upper plate 230T (first holder), arranged in this order from the electrochemical element stack S toward the outside. Similarly, the electrochemical module M also includes, on the bottom of the electrochemical element stack S, a current collector 82, a first lower plate 210B, an elastic member 220B, and a second lower plate 230B (second holder), arranged in this order from the electrochemical element stack S toward the outside. This stack structure is shown in FIGS. 1 and 15.

[0045] The electrochemical element laminate S will be described in detail later.

[0046] (2) Description of components The top plate 230T, the first bottom plate 210B, the elastic member 220B, the second bottom plate 230B, the current collectors 81 and 82, and the container 200 will be further described below.

[0047] Upper plate 230T, first lower plate 210B, and second lower plate 230B are insulating plate-like members, and are made of a ceramic material with high bending strength at high temperatures, such as 99 alumina.

[0048] The elastic member 220B is an elastic, plate-shaped member. In this embodiment, the elastic member 220B is a laminated spring member in which leaf springs having protrusions are laminated. Examples of materials for the elastic member 220B include austenitic stainless steel.

[0049] The upper plate 230T, together with the second lower plate 230B, receives a predetermined clamping pressure from the container 200, and sandwiches the electrochemical element stack S. Here, the clamping pressure is, for example, 1 mm 2 The pressure per unit area is the pressure per square meter.

[0050] (current collector) The electrochemical element stack S is housed in the container 200 in a state where it is sandwiched between a pair of current collectors 81 and 82. The current collectors 81 and 82 are electrically connected to the electrochemical element stack S (electrochemical element A).

[0051] In this embodiment, the current collector 81 includes a current collector plate 81a in contact with the electrochemical element A and a pipe member J through which the first gas flows. The pipe member J is fixed to the current collector plate 81a by welding. In more detail, the current collector 81 includes the current collector plate 81a, a tab portion 81b extending from the current collector plate 81a, a supply pipe member 81c serving as the pipe member J, and a discharge pipe member 81d serving as the pipe member J.

[0052] The current collector 82 includes a current collector plate 82a that contacts the electrochemical device A, and a tab portion 82b that extends from the current collector plate 82a.

[0053] The supply pipe member 81c and the discharge pipe member 81d are made of NCA-1 stainless steel (ferritic stainless steel, 18Cr-3Al-Ti), and are fixed to the current collector plate 81a via a welded portion 81e.

[0054] Current collector plate 81a and current collector plate 82a are made of ferritic stainless steel and preferably have a thickness of 0.5 mm or more and 5 mm or less.

[0055] The tab portion 81b and the tab portion 82b are connected to the output portion 8, and power is taken out from the electrochemical module M.

[0056] 1, an external pipe 61a that supplies the first gas is connected to a supply pipe member 81c (pipe member J) via a connection member 61b. The inside of the supply pipe member 81c is in communication with the inside of the first annular seal portion 42 via the through-hole 81f of the current collector plate 81a. Therefore, the first gas from the external pipe 61a is supplied to the supply path 4. That is, the current collector 81 includes the supply pipe member 81c that supplies the first gas to the electrochemical element A.

[0057] 1, external piping 62a that discharges the first gas to the outside is connected to an exhaust pipe member 81d (pipe member J) via a connection member 62b. As shown in FIG. 4, the inside of the exhaust pipe member 81d communicates with the inside of the second annular seal portion 52 via the through-hole 81g of the current collector plate 81a. Therefore, the first gas from the exhaust channel 5 is discharged to the external piping 62a. That is, the current collector 81 includes the exhaust pipe member 81d that discharges the first gas from the electrochemical device A.

[0058] In this embodiment, the supply pipe member 81c, which is the pipe member J, is connected to the external pipe 61a via the connecting member 61b. The discharge pipe member 81d, which is the pipe member J, is connected to the external pipe 62a via the connecting member 62b. The connecting members 61b, 62b are, for example, joints for connecting pipes. It is preferable that the connecting members 61b, 62b have insulating properties. In this case, the current collector 81 can be insulated from the external pipes 61a, 62a. Note that the connecting members 61b, 62b may be conductive. The supply pipe member 81c (discharge pipe member 81d) and the external pipe 61a (external pipe 62a) may be directly connected without using the connecting members 61b, 62b.

[0059] The supply pipe member 81c and the discharge pipe member 81d are welded to the current collector plate 81a. In this embodiment, as shown in Figures 1 and 4, the welded portion 16a is located on the outside of the supply pipe member 81c and the discharge pipe member 81d. The welded portion 16a may be located on the inside of the supply pipe member 81c and the discharge pipe member 81d, or may be located on both the inside and outside of the supply pipe member 81c and the discharge pipe member 81d.

[0060] 1 to 3, the container 200 that houses the electrochemical element laminate S is a roughly rectangular parallelepiped container. The container 200 includes a box-shaped upper lid 201 (first holding body) that is open at the bottom, and a lower lid 203 (second holding body) that is open at the top. A connecting portion 202 is provided on the end face of the upper lid 201 that faces the lower lid 203, and a connecting portion 205 is provided on the end face of the lower lid 203 that faces the upper lid 201. The upper lid 201 and the lower lid 203 are connected by, for example, welding the connecting portion 202 and the connecting portion 205, thereby forming a rectangular parallelepiped space inside.

[0061] 1, the depth of the lower lid 203 in the vertical direction (the stacking direction of the electrochemical device A) is deeper than the depth of the upper lid 201. However, the relationship between the depths is not limited to this as long as the upper lid 201 and the lower lid 203 can integrally form an internal space. For example, the depth of the upper lid 201 may be deeper than the lower lid 203.

[0062] As shown in FIGS. 1 to 3, a second gas supply part 71 and a second gas exhaust part 72 are formed on a pair of opposing side walls of the lower lid 203 at the center of the container 200 in the vertical direction.

[0063] Here, the second gas supply unit 71 and the second gas exhaust unit 72 are formed in the lower lid 203. However, the positions at which the second gas supply unit 71 and the second gas exhaust unit 72 are formed are not limited thereto, and they may be formed in any position in the container 200. The second gas supply unit 71 and the second gas exhaust unit 72 may be formed in the upper lid 201, for example.

[0064] As shown in FIGS. 1 and 2, the top lid 201 has an opening 201c that is slightly smaller than the outer edge of the top lid 201. In the cross-sectional view of FIG. 1, adjacent to the opening 201c, the inner end facing the electrochemical element laminate S branches into a first end 201a and a second end 201b. The first end 201a extends a predetermined length in a planar direction toward the inside of the container 200, and the second end 201b branches from the first end 201a and extends a predetermined length downward of the container 200. The first end 201a and the second end 201b form an angle of approximately 90° in the cross-sectional view, forming an L-shaped corner. This L-shaped corner is formed along the outer edge of the top lid 201 shown in FIG. 2, on the inner side of the outer edge. As a result, an opening 201c that is slightly smaller than the outer edge of the top cover 201 is formed in the top surface of the top cover 201 at the end of the first end 201a, as shown in FIGS.

[0065] A tubular portion 201d is formed at the first end portion 201a of the upper cover 201. The tubular member J (the supply pipe member 81c and the discharge pipe member 81d) of the current collector 81 is inserted into the tubular portion 201d.

[0066] Similar to the upper cover 201, the lower cover 203 has a first end 203a and a second end 203b that form L-shaped corners at an angle of approximately 90° in the cross-sectional view shown in Fig. 1. The end of the first end 203a forms an opening 203c that is slightly smaller than the outer edge of the lower cover 203, as shown in Fig. 1.

[0067] 1, the upper ends of a pair of opening plate members 240 and an upper plate 230T are fitted into the corners of the L shape formed by the first end 201a and the second end 201b of the upper cover 201. Specifically, the upper plate 230T, which is along the planar direction of the electrochemical element laminate S, is supported with the upper surface of its outer circumferential edge in contact with the lower surface of the first end 201a (part of the inner surface of the corner of the L shape). Furthermore, the opening plate member 240, which is along the side surface of the electrochemical element laminate S, is supported with the outer surface of its upper end in contact with the inner side surface of the second end 201b (part of the inner surface of the corner of the L shape).

[0068] Similarly, the lower ends of a pair of opening plate members 240, a first lower plate 210B, an elastic member 220B, and a second lower plate 230B are fitted into a pair of L-shaped corners facing each other in the planar direction of the lower cover 203.

[0069] The upper surface of the electrochemical element stack S is supported by the upper lid 201 via the upper plate 230T. The lower surface of the electrochemical element stack S is supported by the lower lid 203 via the first lower plate 210B, the elastic member 220B, and the second lower plate 230B.

[0070] With this configuration, the upper lid 201 and the lower lid 203 sandwich the electrochemical element stack S, the upper plate 230T, the first lower plate 210B, the elastic member 220B, the second lower plate 230B, etc. from above and below, and are connected by, for example, welding the connecting portion 202 and the connecting portion 205. During this connection, the upper lid 201 and the lower lid 203 are connected by applying a predetermined clamping pressure to the electrochemical element stack S, etc. In other words, with the upper lid 201 and the lower lid 203 connected, a predetermined clamping pressure is applied to the electrochemical element stack S, the upper plate 230T, the first lower plate 210B, the elastic member 220B, and the second lower plate 230B.

[0071] 3, an opening 203e is formed in the side surface of the lower lid 203. Therefore, a part of the side surface of the electrochemical element laminate S is exposed through the opening 203e. By forming the openings 201c, 203c, and opening 203e in the container 200, the weight of the container 200 can be reduced, and the amount of material required for the container 200 can be reduced. If there is a possibility of an electrical short circuit due to contact between the side surface of the electrochemical element laminate S and the upper lid 201 or the lower lid 203, or both, a side surface insulator 245 made of a material such as mica is installed between the electrochemical element laminate S and the side surface of the upper lid 201 or the lower lid 203.

[0072] The lower lid 203 and the upper lid 201 of the container 200 are joined together to apply a clamping pressure to the electrochemical element stack S. Examples of materials for such a container 200 include ferritic stainless steel, martensitic stainless steel, and composites of these with ceramics. These materials have a smaller thermal expansion coefficient than austenitic stainless steel, and the thermal expansion coefficient of ferritic stainless steel is about 11×10 for SUS430. -6 / ℃. In addition, the thermal expansion coefficient of martensitic stainless steel is approximately 10.4 × 10 for SUS403 and SUS420J1. -6 / ℃, and SUS410 and SUS440C are approximately 10.1 × 10 -6 / ° C. It is also preferable that the container 200 is made of a material that is highly corrosion-resistant.

[0073] The material of the electrochemical element laminate S is preferably the same as that of the container 200. In other words, the materials of the electrochemical element laminate S and the container 200 preferably have a thermal expansion coefficient similar to that of the container 200. In this case, the substrate of the electrochemical element laminate S and the container 200 thermally expand to the same extent, for example, during power generation when the electrochemical element A reaches a high temperature. Therefore, for example, by keeping the difference in thermal expansion between the substrate of the electrochemical element A and the container 200 small, it is possible to prevent damage to the electrochemical element A and leakage of the first gas and the second gas between the electrochemical element A and the container 200.

[0074] (3) Assembly method of electrochemical module M Next, a method for assembling the electrochemical module M will be described.

[0075] A plurality of electrochemical elements A are stacked to prepare an electrochemical element stack S. The configuration and manufacturing method of the electrochemical element stack S will be described later.

[0076] A container 200 for containing the electrochemical element laminate S is also prepared. The container 200 can be manufactured using, but is not limited to, a lost-wax casting method. When using the lost-wax casting method, a hollow model corresponding to the outer shape of the container 200 is manufactured using a thermoplastic material such as beeswax or rosin. This model is then covered with a refractory material such as silica sand or lime powder. The model covered with the refractory material is then heated to dissolve the thermoplastic model. This forms a cavity within the refractory material that corresponds to the model's shape, imitating the shape of the container 200. The material for the container 200 is poured into this cavity and solidified, and the refractory material is then removed. This results in the container 200 having an upper lid 201 and a lower lid 203 manufactured using the lost-wax casting method. Note that the upper lid 201 and the lower lid 203 may be manufactured separately.

[0077] Next, for example, a pair of opening-equipped plate members 240 are placed on both side surfaces of the electrochemical element stack S, and the upper plate 230T (first holding body), current collector 81, electrochemical element stack S, current collector 82, first lower plate 210B, elastic member 220B, and second lower plate 230B (second holding body) are placed in this order and housed in the lower lid 203. The lower lid 203 is covered with the upper lid 201, and the position is adjusted so that a predetermined clamping pressure is applied to the electrochemical element stack S, and the lower lid 203 and the upper lid 201 are joined by welding or the like. In this way, the electrochemical module M is assembled.

[0078] As described above, when the container 200 is manufactured using the lost wax casting method, it is possible to achieve cost reduction through thinning, precision, and mass production.

[0079] Furthermore, by forming the box-shaped container 200, in this embodiment, a manifold space for the air supplied from the second gas supply unit 71 to the electrochemical element stack S can be provided.

[0080] (4) Specific configuration of electrochemical module M Next, a specific configuration of the electrochemical module M will be described with reference to Figures 1 and 4. Figure 4 shows the details of the electrochemical element stack S of Figure 1.

[0081] As shown in Figures 1 and 4, the electrochemical module M includes a container 200 (top lid 201 and bottom lid 203) that houses an electrochemical element stack S, a first gas supply unit 61 that supplies a first gas from the outside of the container 200 to the internal flow path A1 via a supply path 4, a first gas discharge unit 62 that discharges the first gas after the reaction, a second gas supply unit 71 that supplies a second gas from the outside of the container 200 to the flow section A2, a second gas discharge unit 72 that discharges the second gas after the reaction, and an output unit 8 that obtains output associated with the electrochemical reaction in the electrochemical reaction section 3, and is provided within the container 200 with a distribution chamber 9 that distributes the second gas supplied from the second gas supply unit 71 to the flow section A2.

[0082] The distribution chamber 9 is a space located on the side of the electrochemical element stack S that supplies the second gas to the electrochemical element stack S, and the flow passage A2 is opened on the space side and communicates with the space.

[0083] The electrochemical element stack S is housed within the container 200 in a state where it is sandwiched between a pair of current collectors 81, 82, and an output section 8 is extended from these current collectors 81, 82 and is connected freely to a power supply destination outside the container 200 so as to supply power, and at least one of the current collectors 81, 82 is electrically insulated from the container 200 and is contained in the container 200 so as to keep the first gas airtight.

[0084] As a result, the electrochemical module M is supplied with fuel gas from the first gas supply unit 61 and air from the second gas supply unit 71, so that fuel gas enters as shown by the dashed arrows in Figures 1 and 4 and air enters as shown by the solid arrows.

[0085] The fuel gas (sometimes referred to as the first gas) supplied from the first gas supply unit 61 is guided to the supply path 4 through the first through-hole 41 of the uppermost electrochemical element A of the electrochemical element stack S, and flows through the supply path 4 partitioned by the first annular seal portion 42 to the internal flow paths A1 of all the electrochemical elements A. In addition, the air (sometimes referred to as the second gas) supplied from the second gas supply unit 71 temporarily flows into the distribution chamber 9, and then flows through the flow paths A2 formed between the electrochemical elements A.

[0086] Incidentally, when the second plate-like body 2 (part of the plate-like support body 10) is used as a reference, an internal flow path A1 is formed between the first plate-like body 1 and the second plate-like body 2 at the portion where the corrugated second plate-like body 2 bulges out from the first plate-like body 1 (part of the plate-like support body 10), and the corrugated second plate-like body 2 comes into contact with the electrochemical reaction section 3 of the adjacent electrochemical element A, enabling electrical connection. On the other hand, the portion where the corrugated second plate-like body 2 comes into contact with the first plate-like body 1 is electrically connected to the first plate-like body 1, and a flow section A2 is formed between the second plate-like body 2 and the electrochemical reaction section 3 of the adjacent electrochemical element A.

[0087] 14 shows an electrochemical element A with a cross section including the internal flow path A1 and an electrochemical element A with a cross section including the flow section A2, arranged side by side for convenience, and the fuel gas supplied from the first gas supply section 61 reaches the distribution section A12 (see FIGS. 5, 7, and 9), spreads along the width direction of one end side through the distribution section A12, and reaches each sub-flow path A11 of the internal flow path A1 (see FIGS. 5, 7, and 9). In this case, the first gas can be distributed evenly from the distribution section A12 to the multiple sub-flow paths A11, and each electrochemical element can generate an equal electrochemical output.

[0088] As a result, the fuel gas that has entered each sub-flow path A11 can enter the electrode layer 31 and the electrolyte layer 32 via the gas flow permitting portion 1A. The fuel gas further travels through the internal flow path A1 together with the fuel gas that has undergone the electrochemical reaction, passes through the confluence portion A13 and the second through-hole portion 51, and proceeds to the discharge path 5 formed by the second annular seal portion 52, and is discharged to the outside of the container 200 through the first gas discharge portion 62 together with the fuel gas that has undergone the electrochemical reaction from the other electrochemical elements A.

[0089] On the other hand, air supplied from the second gas supply unit 71 enters the flow section A2 via the distribution chamber 9 and can enter the counter electrode layer 33 and the electrolyte layer 32. The air, together with the air that has undergone the electrochemical reaction, further travels through the flow section A2 along the electrochemical reaction unit 3 and is discharged to the outside of the container 200 through the second gas discharge unit 72.

[0090] The electricity generated in the electrochemical reaction section 3 in accordance with the flow of fuel gas and air is connected in series between the current collectors 81, 82 due to contact between the electrochemical reaction section 3 of the adjacent electrochemical element A and the second plate-like body 2, and the combined output is extracted from the output section 8.

[0091] (5) Specific Configuration of Electrochemical Element Laminate S Next, a specific configuration of the electrochemical element laminate S will be described. The electrochemical element laminate S is formed by laminating a plurality of electrochemical elements A.

[0092] The electrochemical device A will be described with reference to FIGS.

[0093] (electrochemical element) As shown in FIGS. 5 to 13, the electrochemical device A includes a plate-like support 10 having an internal flow path A1 formed between the opposing surfaces of a first plate-like body 1 and a second plate-like body 2.

[0094] The plate-shaped support 10 is provided, in at least a part of the first plate-shaped body 1 and the second plate-shaped body 2 constituting the plate-shaped support 10, with a gas flow-permitting portion 1A that allows gas to pass between the internal flow path A1 on the inside of the plate-shaped support 10 and the outside, and an electrochemical reaction portion 3 that covers all or part of the gas flow-permitting portion 1A and has a membrane-like electrode layer 31, a membrane-like electrolyte layer 32, and a membrane-like counter electrode layer 33 in this order (see Figures 9 to 13).

[0095] Furthermore, the plate-shaped support 10 has a first penetration portion 41 at one end which forms a supply path 4 that supplies a first gas, which is one of a reducing component gas such as a fuel gas and an oxidizing component gas such as air, to the internal flow path A1 from outside in the direction of penetration through the surface, and a second penetration portion 51 at the other end which forms a discharge path 5 that discharges the first gas that has flowed through the internal flow path A1 outward in the direction of penetration through the surface of the plate-shaped support (see Figures 5, 7, 12, and 13; it will also be understood that the supply path 4, etc. and the discharge path 5, etc. are symmetrical and have similar structures).

[0096] (Plate-shaped support) The first plate-like body 1 supports the electrochemical reaction unit 3 having the electrode layer 31, the electrolyte layer 32, and the counter electrode layer 33, thereby maintaining the strength of the electrochemical device A. In other words, the first plate-like body 1 is a support that supports the electrochemical reaction unit 3.

[0097] The material for the first plate-shaped body 1 is preferably a material with excellent electronic conductivity, heat resistance, oxidation resistance, and corrosion resistance. Examples include ferritic stainless steel, austenitic stainless steel, and nickel-based alloys. A chromium-containing alloy is particularly preferred. In this embodiment, the first plate-shaped body 1 is made of an Fe—Cr alloy containing 18 to 25% by mass of Cr. However, particularly preferred materials include an Fe—Cr alloy containing 0.05% by mass or more of Mn, an Fe—Cr alloy containing 0.15 to 1.0% by mass of Ti, an Fe—Cr alloy containing 0.15 to 1.0% by mass of Zr, an Fe—Cr alloy containing Ti and Zr with a total content of Ti and Zr of 0.15 to 1.0% by mass, and an Fe—Cr alloy containing 0.10 to 1.0% by mass of Cu.

[0098] The second plate-like body 2 is superimposed on the first plate-like body 1 and integrated with it by welding the peripheral edge portion 1a to form the plate-like support body 10 (see FIGS. 6 to 13). The second plate-like body 2 may be divided into multiple pieces relative to the first plate-like body 1, or conversely, the first plate-like body 1 may be divided into multiple pieces relative to the second plate-like body 2. Furthermore, when integrating the first and second plate-like bodies, other means such as adhesion or fitting can be used instead of welding, and integration may be performed at a portion other than the peripheral edge portion 1a as long as the internal flow path can be formed separately from the outside.

[0099] The first plate-like body 1 has a gas flow-permitting portion 1A formed by a large number of through-holes 11 that penetrate from the front surface to the back surface (see FIGS. 9 to 13). The through-holes 11 can be formed in the first plate-like body 1 by laser processing, for example. The through-holes 11 have the function of allowing gas to pass from the back surface to the front surface of the first plate-like body 1. The gas flow-permitting portion 1A is preferably provided in an area of ​​the first plate-like body 1 that is smaller than the area where the electrode layer 31 is provided.

[0100] A metal oxide layer 12 (see FIG. 14 , described later) is provided on the surface of the first plate-like body 1 as a diffusion-suppressing layer. That is, the diffusion-suppressing layer is formed between the first plate-like body 1 and the electrode layer 31 (described later). The metal oxide layer 12 is provided not only on the surface exposed to the outside of the first plate-like body 1 but also on the contact surface (interface) with the electrode layer 31. It can also be provided on the inner surface of the through-hole 11. This metal oxide layer 12 can suppress interdiffusion of elements between the first plate-like body 1 and the electrode layer 31. For example, if ferritic stainless steel containing chromium is used as the first plate-like body 1, the metal oxide layer 12 is mainly composed of chromium oxide. The metal oxide layer 12, which is mainly composed of chromium oxide, suppresses the diffusion of chromium atoms and the like from the first plate-like body 1 into the electrode layer 31 and the electrolyte layer 32. The thickness of the metal oxide layer 12 may be any thickness that achieves both high diffusion prevention performance and low electrical resistance.

[0101] The metal oxide layer 12 can be formed by various methods, but a method of oxidizing the surface of the first plate-like body 1 to form a metal oxide is preferably used. The metal oxide layer 12 may also be formed on the surface of the first plate-like body 1 by a spray coating method (such as thermal spraying, aerosol deposition, aerosol gas deposition, powder jet deposition, particle jet deposition, or cold spray), a PVD method such as sputtering or PLD, or a CVD method, or by plating and oxidation treatment. Furthermore, the metal oxide layer 12 may contain a highly conductive spinel phase.

[0102] When ferritic stainless steel is used for the first plate 1, its thermal expansion coefficient is similar to that of YSZ (yttria-stabilized zirconia) and GDC (gadolinium-doped ceria, also known as CGO), which are materials for the electrode layer 31 and the electrolyte layer 32. Therefore, the electrochemical element A is less susceptible to damage even when subjected to repeated low- and high-temperature cycles. This is preferable because it allows for an electrochemical element A with excellent long-term durability. The first plate 1 has multiple through-holes 11 extending from the front surface to the back surface. For example, the through-holes 11 can be formed in the first plate 1 by mechanical, chemical, or optical drilling. The through-holes 11 allow gas to pass from the back surface of the first plate 1 to the front surface. Porous metal can also be used to impart gas permeability to the first plate 1. For example, the first plate 1 can be made of sintered metal, foam metal, or the like.

[0103] The plate-like support (first plate 1, second plate 2) 10 has an internal flow path A1 inside. The internal flow path A1 is formed between the first plate 1 and the second plate 2. The internal flow path A1 is provided with a plurality of sub-flow paths A11, A11 in a region facing the gas flow-permitting portion 1A of the first plate 1. The plurality of sub-flow paths A11, A11 are formed by processing the second plate 2 into a corrugated plate shape. The plurality of sub-flow paths A11, A11 extend from one end side to the other end side (first direction side) in a direction along the plate-like surface of the plate-like support 10, i.e., along the flow direction of the first gas. The plurality of sub-flow paths A11, A11 are also spaced apart from one another in a direction (second direction) intersecting from one end side to the other end side in a direction along the plate-like surface of the plate-like support 10.

[0104] The second plate 2 is formed in a corrugated shape on both its front and back sides, and the surface opposite to the surface defining the internal flow path A1 is electrically connected to the electrochemical reaction section 3 of the adjacent electrochemical element A. A passage formed near the contact point between the corrugated second plate 2 and the first plate 1 functions as the flow path A2. In other words, the second plate 2 is a separator that separates the internal flow path A1, which is the flow path for the first gas, from the flow path A2, which is the flow path for the second gas. The electrochemical reaction section 3, the first plate 1 serving as a support, and the second plate 2 serving as a separator are stacked with a load applied in the stacking direction to form an electrochemical element stack S.

[0105] More specifically, a plurality of sub-flow passages A11 are provided in parallel along the long sides of the rectangular plate-like support 10, constituting an internal flow passage A1 extending from the supply passage 4 at one end to the discharge passage 5 at the other end. The connection between the first through-hole 41 and the internal flow passage A1 bulges downward from the contact portion with the first plate-like body 1 and includes a distribution section A12 that distributes the first gas supplied from the first through-hole 41 to each of the sub-flow passages A11 (see FIG. 5). The connection between the second through-hole 51 and the internal flow passage A1 bulges downward from the contact portion with the first plate-like body 1 and includes a confluence section A13 that collects the first gas that has flowed through each of the sub-flow passages A11 and leads it to the second through-hole 51 (see FIGS. 5, 7, 8, 10 to 13; it will be understood that the supply passages 4 and the discharge passages 5 are symmetrical and have the same structure). Furthermore, the material of the second plate-like body 2 is preferably a heat-resistant metal, and it is even more preferable if it is the same material as the first plate-like body 1 from the standpoint of reducing the thermal expansion difference with the first plate-like body 1 and ensuring the reliability of joining such as welding.

[0106] (embossed area) 5, 7, 11-13, and 15, in this embodiment, an embossed portion 15 recessed toward the internal flow path A1 is formed in the first plate-like body 1. A bottom 15a of the embossed portion 15 is joined to the second plate-like body 2. The joining of the bottom 15a of the embossed portion 15 to the second plate-like body 2 is preferably performed by welding.

[0107] The embossed portions can be formed on the first plate-like body 1 by stamping using an intaglio plate and a relief plate. The embossed portions can also be formed on the first plate-like body 1 by other methods.

[0108] A through hole 16 penetrating the first plate-like body 1 and the second plate-like body 2 is formed at a position corresponding to the bottom 15a of the embossed portion 15. A welded portion 16a is provided around the entire periphery of the through hole 16 so as to suppress leakage of the second gas from the internal flow path A1. The second gas can flow between the upper and lower sides of the plate-like support body 10 through the through hole 16.

[0109] As shown in FIG. 7, a welded portion 16a is provided around the entire periphery of the through-hole 16 so as to suppress leakage of the second gas from the internal flow path A1.

[0110] The through holes 16 may be formed by drilling holes in each of the first plate-like body 1 and the second plate-like body 2 before the first plate-like body 1 and the second plate-like body 2 are joined together. The through holes 16 may be formed by drilling holes in the plate-like support body 10 after the first plate-like body 1 and the second plate-like body 2 are joined together. The welded regions 16a may be formed before the through holes 16 are drilled, or may be formed after the through holes 16 are drilled.

[0111] In this embodiment, as shown in Figures 5 and 15, the plate-shaped support body 10 has two embossed areas 15. The embossed areas 15 are provided not in the middle of the first plate-shaped body 1 in the longitudinal direction (the area where the gas flow-permitting section 1A is provided), but at the longitudinal ends of the first plate-shaped body 1. One embossed area 15 is provided at one longitudinal end of the first plate-shaped body 1, and the other embossed area 15 is provided at the other longitudinal end of the first plate-shaped body 1.

[0112] 5, one embossed area 15 is provided at a position corresponding to the distribution area A12 on the first plate-like body 1. Another embossed area 15 is provided at a position corresponding to the junction area A13 on the first plate-like body 1.

[0113] 5, one embossed portion 15 is provided at a position offset in the short direction of the first plate-like body 1 with respect to the first through-hole 41 (supply path 4, first annular seal portion 42). The other embossed portion 15 is provided at a position offset in the short direction of the first plate-like body 1 with respect to the second through-hole 51 (discharge path 5, second annular seal portion 52).

[0114] (flat plate structure) As shown in Figures 5, 9, and 10-14, the electrochemical element A includes a flat plate-like structure 92 disposed between a support (first plate-like body 1) and a separator (second plate-like body 2) and capable of transmitting a load from either the support or the separator to the other. The flat plate-like structure 92 is disposed in the internal flow path A1. The flat plate-like structure 92 is a member extending in a flat plate shape along the first plate-like body 1 and the second plate-like body 2, and thus comes into contact with the first plate-like body 1 and the second plate-like body 2 over a wide area. Therefore, the load in the stacking direction is transmitted over a wide area, making it possible to uniformly transmit the load in the electrochemical element stack S. This makes it possible to prevent problems such as damage to the components of the electrochemical element stack S and non-uniform flow of the first gas due to deformation of the components.

[0115] Furthermore, since the flat plate-like structure 92 transmits force in the stacking direction in addition to the joint portion between the first plate-like body 1 and the second plate-like body 2, the load is transmitted more uniformly in the electrochemical element stack S. Furthermore, since the flat plate-like structure 92 is disposed in the internal flow path A1, deformation of the internal flow path A1 is suppressed by the flat plate-like structure 92. Therefore, it is possible to suppress a decrease in performance of the electrochemical element A due to deformation of the internal flow path A1.

[0116] It is preferable that the flat plate-like structure 92 is electrically conductive. It is also preferable that the flat plate-like structure 92 is made of metal. In this embodiment, the flat plate-like structure 92 is made of Ni or stainless steel.

[0117] The flat plate-like structure 92 is preferably a metal mesh, which is produced by weaving thin metal wires into a net shape.

[0118] It is preferable that the flat plate-like structure 92 is a lath metal. A lath metal is a metal lath and is also called an expanded metal. A lath metal (expanded metal) is processed by cutting a flat metal plate and stretching it to have, for example, a diamond-shaped mesh.

[0119] 5, the flat plate-like structures 92 extend in the longitudinal direction (the longitudinal direction of the plate-like support 10) to the vicinity of the longitudinal end of the electrochemical reaction section 3. Furthermore, as shown in FIGS. 10-13, the flat plate-like structures 92 extend to the vicinity of the longitudinal end of the electrode layer 31. This makes the flat plate-like structures 92 approximately the same size as the electrochemical reaction section 3, thereby suppressing deformation of the electrochemical reaction section 3 and suppressing performance degradation of the electrochemical element stack S.

[0120] As described above, in this embodiment, the second plate-like body 2 is formed in a corrugated shape, and the apex portions 2a of the waves divide the sub-flow paths A11 (see FIGS. 5, 9, and 14). The apex portions 2a extend along the longitudinal direction of the second plate-like body 2. As shown in FIG. 5, the longitudinal ends of the flat plate-like structure 92 are located more inward than the longitudinal ends of the apex portions 2a.

[0121] The second plate-like body 2 is formed in a corrugated shape, but due to processing errors, the longitudinal ends of the wave crests 2a may protrude beyond the remaining portions of the crests 2a. Therefore, in a configuration in which the longitudinal ends of the wave crests 2a contact the flat plate-like structure 92, there is a possibility that local load concentration may occur. In this embodiment, the longitudinal ends of the flat plate-like structure 92 are located more inward than the longitudinal ends of the crests 2a, so the longitudinal ends of the wave crests 2a do not contact the flat plate-like structure 92. Therefore, local load concentration can be avoided.

[0122] As shown in FIGS. 5, 9, and 10-14, the thickness of the flat plate-like structure 92 may be approximately the same as the distance between the support (first plate 1) and the separator (second plate 2). Specifically, in the illustrated example, the thickness of the flat plate-like structure 92 is approximately the same as the distance between the first plate 1 and the vertex 2a of the second plate 2. The thickness of the flat plate-like structure 92 may be smaller than the distance between the first plate 1 and the second plate 2. It is preferable that the thickness of the flat plate-like structure 92 is 80% or more of the distance between the support (first plate 1) and the separator (second plate 2). This prevents excessive displacement of the first plate 1 or the second plate 2, thereby maintaining the performance of the electrochemical element stack S.

[0123] In this embodiment, the flat plate-like structure 92 is disposed between a first plate-like body 1 (support) and a second plate-like body 2 (separator).

[0124] (Electrochemical reaction section)

[0125] (electrode layer) As shown in FIGS. 9 to 14, the electrode layer 31 can be provided as a thin layer on the front surface of the first plate-like body 1 in an area larger than the area where the through holes 11 are provided. When the electrode layer 31 is a thin layer, its thickness can be, for example, about 1 μm to 100 μm, preferably 5 μm to 50 μm. Such a thickness makes it possible to reduce the amount of expensive electrode layer material used, thereby reducing costs, while ensuring sufficient electrode performance. The entire area where the through holes 11 are provided is covered with the electrode layer 31. In other words, the through holes 11 are formed inside the area of ​​the first plate-like body 1 where the electrode layer 31 is formed. In other words, all of the through holes 11 are provided facing the electrode layer 31.

[0126] The electrode layer 31 has a plurality of pores inside and on the surface thereof to provide gas permeability.

[0127] That is, the electrode layer 31 is formed as a porous layer. The electrode layer 31 is formed, for example, so that its density is 30% or more and less than 80%. The size of the pores can be appropriately selected so that the electrochemical reaction proceeds smoothly. Note that the density is the proportion of the space occupied by the material constituting the layer, and can be expressed as (1 - porosity), and is equivalent to the relative density.

[0128] The material of the electrode layer 31 may be a composite material such as NiO-GDC, Ni-GDC, NiO-YSZ, Ni-YSZ, CuO-CeO2, or Cu-CeO2. In these examples, GDC, YSZ, and CeO2 can be called aggregates of the composite material. The electrode layer 31 is preferably formed by a low-temperature firing method (e.g., a wet method using firing at a low temperature without firing at a high temperature above 1100°C), a spray coating method (thermal spraying, aerosol deposition, aerosol gas deposition, powder jet deposition, particle jet deposition, cold spray, etc.), a PVD method (sputtering, pulsed laser deposition, etc.), a CVD method, etc. These processes, which can be used in a low-temperature range, can produce a good electrode layer 31 without firing at a high temperature above 1100°C, for example. Therefore, this is preferable because it prevents damage to the first plate-like body 1 and suppresses interdiffusion of elements between the first plate-like body 1 and the electrode layer 31, resulting in an electrochemical device A with excellent durability. Furthermore, using a low-temperature firing method is even more preferable because it facilitates handling of raw materials.

[0129] (middle class) The intermediate layer 34 can be formed as a thin layer on the electrode layer 31 in a state where it covers the electrode layer 31. When it is a thin layer, the thickness can be, for example, about 1 μm to 100 μm, preferably about 2 μm to 50 μm, and more preferably about 4 μm to 25 μm. Such a thickness makes it possible to ensure sufficient performance while reducing the amount of expensive material used for the intermediate layer 34, thereby reducing costs. Examples of materials that can be used for the intermediate layer 34 include YSZ (yttria-stabilized zirconia), SSZ (scandium-stabilized zirconia), GDC (gadolinium-doped ceria), YDC (yttrium-doped ceria), and SDC (samarium-doped ceria). Ceria-based ceramics are particularly suitable.

[0130] The intermediate layer 34 is preferably formed by a low-temperature firing method (e.g., a wet method using firing at a low temperature without firing at a high temperature above 1100°C), a spray coating method (such as thermal spraying, aerosol deposition, aerosol gas deposition, powder jet deposition, particle jet deposition, or cold spray), a PVD method (such as sputtering or pulsed laser deposition), or a CVD method. These low-temperature deposition processes can be used to obtain the intermediate layer 34 without firing at a high temperature above 1100°C. This prevents interdiffusion of elements between the first plate-like body 1 and the electrode layer 31 without damaging the first plate-like body 1, resulting in an electrochemical device A with excellent durability. Furthermore, a low-temperature firing method is more preferable because it facilitates handling of raw materials.

[0131] The intermediate layer 34 preferably has oxygen ion (oxide ion) conductivity. Furthermore, it is more preferable that the intermediate layer 34 has mixed conductivity of oxygen ions (oxide ions) and electrons. The intermediate layer 34 having these properties is suitable for application to the electrochemical device A.

[0132] (electrolyte layer) As shown in FIGS. 9 to 14, the electrolyte layer 32 is formed as a thin layer on the intermediate layer 34, covering the electrode layer 31 and the intermediate layer 34. Alternatively, the electrolyte layer 32 may be formed as a thin film having a thickness of 10 μm or less. Specifically, the electrolyte layer 32 is provided over (straddles) the intermediate layer 34 and the first plate-like body 1. By configuring the electrolyte layer 32 in this way and joining the electrolyte layer 32 to the first plate-like body 1, the electrochemical element as a whole can have excellent robustness.

[0133] 9, the electrolyte layer 32 is provided on the front surface of the first plate-like body 1 in an area larger than the area in which the through-holes 11 are provided. In other words, the through-holes 11 are formed inside the area in the first plate-like body 1 in which the electrolyte layer 32 is formed.

[0134] Furthermore, gas leakage from the electrode layer 31 and the intermediate layer (not shown) can be suppressed around the electrolyte layer 32. Specifically, when the electrochemical element A is used as a component of an SOFC, gas is supplied to the electrode layer 31 from the back side of the first plate-like body 1 through the through-holes 11 during operation of the SOFC. Gas leakage can be suppressed in the area where the electrolyte layer 32 contacts the first plate-like body 1 without providing a separate member such as a gasket. In this embodiment, the electrolyte layer 32 completely covers the periphery of the electrode layer 31, but the electrolyte layer 32 may be provided on top of the electrode layer 31 and the intermediate layer 34, and a gasket or the like may be provided around the periphery.

[0135] The electrolyte layer 32 may be made of an electrolyte material that conducts oxygen ions, such as YSZ (yttria-stabilized zirconia), SSZ (scandium-stabilized zirconia), GDC (gadolinium-doped ceria), YDC (yttrium-doped ceria), SDC (samarium-doped ceria), or LSGM (strontium-magnesium-doped lanthanum gallate), or a perovskite-type oxide that conducts hydrogen ions. In particular, zirconia-based ceramics are preferably used. Using zirconia-based ceramics for the electrolyte layer 32 allows the operating temperature of an SOFC using electrochemical element A to be higher than that of ceria-based ceramics or various hydrogen ion conductive materials. For example, when electrochemical element A is used in an SOFC, a highly efficient SOFC system can be constructed by using a material such as YSZ, which can exhibit high electrolyte performance even at high temperatures of approximately 650°C or higher, as the material for the electrolyte layer 32, using a hydrocarbon-based raw fuel such as city gas or LPG as the raw fuel, and converting the raw fuel into SOFC anode gas by steam reforming or the like, using the heat generated in the SOFC cell stack to reform the raw fuel gas.

[0136] The electrolyte layer 32 is preferably formed by a low-temperature firing method (e.g., a wet method using firing at a low temperature without firing at a high temperature above 1100°C), a spray coating method (thermal spraying, aerosol deposition, aerosol gas deposition, powder jet deposition, particle jet deposition, cold spray, etc.), a PVD method (sputtering, pulsed laser deposition, etc.), a CVD (chemical vapor deposition) method, etc. These film formation processes that can be used in a low-temperature range can produce an electrolyte layer 32 that is dense and has high airtightness and gas barrier properties without firing at a high temperature above 1100°C, for example. This can suppress damage to the first plate-like body 1 and interdiffusion of elements between the first plate-like body 1 and the electrode layer 31, resulting in an electrochemical device A with excellent performance and durability. In particular, low-temperature firing methods and spray coating methods are preferred because they allow for low-cost devices to be produced. Furthermore, spray coating is more preferable because it is easy to obtain a dense electrolyte layer that is airtight and has high gas barrier properties in a low temperature range.

[0137] The electrolyte layer 32 is densely structured to prevent gas leakage of the anode gas and the cathode gas and to exhibit high ionic conductivity. The density of the electrolyte layer 32 is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. When the electrolyte layer 32 is a uniform layer, the density thereof is preferably 95% or more, and more preferably 98% or more. Furthermore, when the electrolyte layer 32 is structured in a multi-layered structure, it is preferable that at least some of the layers include a layer with a density of 98% or more (dense electrolyte layer), and more preferably a layer with a density of 99% or more (dense electrolyte layer). When such a dense electrolyte layer is included as part of the electrolyte layer, it becomes easier to form a dense electrolyte layer that is airtight and has high gas barrier properties, even if the electrolyte layer is composed of multiple layers.

[0138] (Reaction prevention layer) The reaction prevention layer 35 can be formed as a thin layer on the electrolyte layer 32. When the layer is thin, its thickness can be, for example, about 1 μm to 100 μm, preferably about 2 μm to 50 μm, and more preferably about 3 μm to 15 μm. This thickness reduces the amount of expensive reaction prevention layer material used, thereby reducing costs and ensuring sufficient performance. The material for the reaction prevention layer can be any material that can prevent a reaction between the components of the electrolyte layer 32 and the components of the counter electrode layer 33, such as a ceria-based material. A material containing at least one element selected from the group consisting of Sm, Gd, and Y is preferably used as the material for the reaction prevention layer 35. It is preferable that the material contains at least one element selected from the group consisting of Sm, Gd, and Y, and that the total content of these elements is 1.0% by mass or more and 10% by mass or less. By introducing the reaction prevention layer 35 between the electrolyte layer 32 and the counter electrode layer 33, the reaction between the constituent materials of the counter electrode layer 33 and the electrolyte layer 32 is effectively suppressed, thereby improving the long-term stability of the performance of the electrochemical device A. The reaction prevention layer 35 is preferably formed using a method that allows it to be formed at a processing temperature of 1100°C or less, because this prevents damage to the first plate-like body 1 and also suppresses interdiffusion of elements between the first plate-like body 1 and the electrode layer 31, resulting in an electrochemical device A with excellent performance and durability. For example, the reaction prevention layer 35 can be formed by a low-temperature firing method (e.g., a wet method that uses a firing process at a low temperature that does not involve firing at a high temperature above 1100°C), a spray coating method (such as a thermal spraying method, an aerosol deposition method, an aerosol gas deposition method, a powder jet deposition method, a particle jet deposition method, or a cold spray method), a PVD method (such as a sputtering method or a pulsed laser deposition method), or a CVD method. In particular, low-temperature firing or spray coating is preferred because it allows for low-cost elements to be realized. Furthermore, low-temperature firing is even more preferred because it allows for easy handling of raw materials.

[0139] (Counter electrode layer) As shown in FIGS. 9 to 14, the counter electrode layer 33 can be formed as a thin layer on the electrolyte layer 32 or the reaction prevention layer 35. When the counter electrode layer 33 is formed as a thin layer, its thickness can be, for example, approximately 1 μm to 100 μm, preferably 5 μm to 50 μm. This thickness reduces the amount of expensive counter electrode layer material used, thereby reducing costs, while ensuring sufficient electrode performance. Examples of materials that can be used for the counter electrode layer 33 include composite oxides such as LSCF and LSM, ceria-based oxides, and mixtures thereof. It is particularly preferable that the counter electrode layer 33 contains a perovskite-type oxide containing two or more elements selected from the group consisting of La, Sr, Sm, Mn, Co, and Fe. The counter electrode layer 33 formed using these materials functions as a cathode.

[0140] The counter electrode layer 33 is preferably formed using a method capable of forming the counter electrode layer 33 at a processing temperature of 1100°C or less, since this method can prevent damage to the first plate 1 and suppress interdiffusion of elements between the first plate 1 and the electrode layer 31, thereby achieving an electrochemical device A with excellent performance and durability. For example, a low-temperature firing method (e.g., a wet method using a firing process at a low temperature without firing at a high temperature above 1100°C), a spray coating method (thermal spraying, aerosol deposition, aerosol gas deposition, powder jet deposition, particle jet deposition, cold spray, etc.), a PDV method (sputtering, pulsed laser deposition, etc.), a CVD method, etc., can be used. Low-temperature firing methods and spray coating methods are particularly preferred, as they allow for low-cost devices. Furthermore, low-temperature firing methods are even more preferred, as they facilitate the handling of raw materials.

[0141] By configuring the electrochemical reaction unit 3 in this way, when the electrochemical reaction unit 3 is made to function as a fuel cell (electrochemical power generation cell), the electrochemical element A can be used as a power generation cell of a solid oxide fuel cell. For example, a fuel gas containing hydrogen as a first gas is supplied to the electrode layer 31 through the through-holes 11 from the back surface of the first plate-like body 1, and air as a second gas is supplied to the counter electrode layer 33, which is the counter electrode of the electrode layer 31, and the temperature is maintained at an operating temperature of, for example, about 700°C. Then, oxygen O2 contained in the air is converted into electrons e in the counter electrode layer 33. - reacts with oxygen ions O 2- The oxygen ions O 2- The hydrogen H2 contained in the supplied fuel gas moves through the electrolyte layer 32 to the electrode layer 31. In the electrode layer 31, the hydrogen H2 contained in the supplied fuel gas is converted into oxygen ions O 2- reacts with water H2O and electrons e - is generated. When an electrolyte material that conducts hydrogen ions is used for the electrolyte layer 32, hydrogen H2 contained in the fuel gas flowing through the electrode layer 31 is converted into electrons e - releases hydrogen ions H + The hydrogen ions H + moves through the electrolyte layer 32 to the counter electrode layer 33. At the counter electrode layer 33, oxygen O2 and hydrogen ions H + , electronic e - reacts to produce water H2O. The above reaction generates an electromotive force as an electrochemical output between the electrode layer 31 and the counter electrode layer 33. In this case, the electrode layer 31 functions as the fuel electrode (anode) of the fuel cell, and the counter electrode layer 33 functions as the air electrode (cathode).

[0142] 9 to 13, in this embodiment, the electrochemical reaction unit 3 includes an intermediate layer 34 between the electrode layer 31 and the electrolyte layer 32, as shown in FIG. 14. Furthermore, a reaction prevention layer 35 is provided between the electrolyte layer 32 and the counter electrode layer 33.

[0143] (Method of manufacturing electrochemical reaction section) Next, a description will be given of a method for manufacturing the electrochemical reaction section 3. Note that, since the intermediate layer 34 and the reaction prevention layer 35 described below are omitted in Figures 9 to 13, the description will be made mainly with reference to Figure 14.

[0144] (Electrode layer formation step) In the electrode layer formation step, the electrode layer 31 is formed as a thin film on an area of ​​the front surface of the first plate-like body 1 that is larger than the area where the through-holes 11 are formed. The through-holes 11 in the first plate-like body 1 can be formed by laser processing or the like. As described above, the electrode layer 31 can be formed by low-temperature firing (a wet method that performs firing at a low temperature of 1100°C or less), spray coating (thermal spraying, aerosol deposition, aerosol gas deposition, powder jet deposition, particle jet deposition, cold spray, or other methods), PVD (sputtering, pulsed laser deposition, or other methods), CVD, or the like. Whichever method is used, it is preferable to perform the process at a temperature of 1100°C or less to prevent deterioration of the first plate-like body 1.

[0145] When the electrode layer forming step is performed by a low-temperature firing method, the step is specifically performed as follows. First, a material powder of the electrode layer 31 is mixed with a solvent (dispersion medium) to prepare a material paste, which is then applied to the front surface of the first plate-like body 1 and fired at 800°C to 1100°C.

[0146] (Diffusion suppression layer formation step) During the firing process in the electrode layer formation step described above, a metal oxide layer 12 (diffusion-preventing layer) is formed on the surface of the first plate-like body 1. It is preferable that the firing process includes a firing process in which the firing atmosphere is set under atmospheric conditions with a low oxygen partial pressure, since this effectively suppresses interdiffusion of elements and forms a high-quality metal oxide layer 12 (diffusion-preventing layer) with low resistance. The electrode layer formation step may also include a separate diffusion-preventing layer formation step, including when a coating method is used without firing. In either case, it is desirable to perform the process at a processing temperature of 1100°C or less, which can prevent damage to the first plate-like body 1.

[0147] (Intermediate layer formation step) In the intermediate layer forming step, a thin intermediate layer 34 is formed on the electrode layer 31 so as to cover the electrode layer 31. As described above, the intermediate layer 34 can be formed by a low-temperature firing method (a wet method in which firing is performed at a low temperature of 1100°C or less), a spray coating method (such as a thermal spraying method, an aerosol deposition method, an aerosol gas deposition method, a powder jet deposition method, a particle jet deposition method, or a cold spray method), a PVD method (such as a sputtering method or a pulsed laser deposition method), or a CVD method. Whichever method is used, it is preferable to perform the formation at a temperature of 1100°C or less in order to prevent deterioration of the first plate-like body 1.

[0148] When the intermediate layer forming step is performed by a low-temperature firing method, the following specific example is performed.

[0149] First, a material powder for the intermediate layer 34 is mixed with a solvent (dispersion medium) to form a material paste, which is then applied to the front surface of the first plate-like body 1. The intermediate layer 34 is then compression-molded (intermediate layer smoothing step) and fired at 1100°C or less (intermediate layer firing step). The intermediate layer 34 can be rolled by, for example, CIP (Cold Isostatic Pressing), roll pressing, or RIP (Rubber Isostatic Pressing). The intermediate layer 34 is preferably fired at a temperature of 800°C or more and 1100°C or less. This is because such a temperature allows for the formation of a high-strength intermediate layer 34 while suppressing damage and deterioration of the first plate-like body 1. The intermediate layer 34 is more preferably fired at 1050°C or less, and even more preferably at 1000°C or less. This is because the lower the firing temperature of the intermediate layer 34, the more effectively the electrochemical element A can be formed while suppressing damage and deterioration of the first plate-like body 1. Furthermore, the order of the intermediate layer smoothing step and the intermediate layer firing step can be reversed.

[0150] The intermediate layer smoothing step can also be carried out by lapping, leveling, cutting and polishing the surface, or the like.

[0151] (Electrolyte layer formation step) In the electrolyte layer formation step, the electrolyte layer 32 is formed as a thin layer on the intermediate layer 34, covering the electrode layer 31 and the intermediate layer 34. Alternatively, the electrolyte layer 32 may be formed as a thin film having a thickness of 10 μm or less. As described above, the electrolyte layer 32 can be formed by a low-temperature firing method (a wet method in which firing is performed at a low temperature of 1100°C or less), a spray coating method (such as thermal spraying, aerosol deposition, aerosol gas deposition, powder jet deposition, particle jet deposition, or cold spray), a PVD method (such as sputtering or pulsed laser deposition), or a CVD method. Whichever method is used, it is preferable to perform the formation at a temperature of 1100°C or less to prevent deterioration of the first plate-like body 1.

[0152] To form a high-quality electrolyte layer 32 that is dense, airtight, and has excellent gas barrier properties at temperatures below 1100° C., it is desirable to perform the electrolyte layer formation step by spray coating. In this case, the material for the electrolyte layer 32 is sprayed toward the intermediate layer 34 on the first plate-like body 1 to form the electrolyte layer 32.

[0153] (Reaction prevention layer formation step) In the reaction prevention layer formation step, the reaction prevention layer 35 is formed as a thin layer on the electrolyte layer 32. As described above, the reaction prevention layer 35 can be formed by a low-temperature firing method (a wet method in which firing is performed at a low temperature of 1100°C or less), a spray coating method (such as thermal spraying, aerosol deposition, aerosol gas deposition, powder jet deposition, particle jet deposition, or cold spray), a PVD method (such as sputtering or pulsed laser deposition), or a CVD method. Whichever method is used, it is preferable to perform the process at a temperature of 1100°C or less to prevent deterioration of the first plate-like body 1. To flatten the upper surface of the reaction prevention layer 35, for example, a leveling process or a cutting / polishing process may be performed after the formation of the reaction prevention layer 35, or a press process may be performed after wet formation and before firing.

[0154] (Counter electrode layer formation step) In the counter electrode layer formation step, the counter electrode layer 33 is formed in a thin layer state on the reaction prevention layer 35. As described above, the counter electrode layer 33 can be formed by a low-temperature firing method (a wet method in which firing is performed at a low temperature of 1100°C or less), a spray coating method (such as a thermal spraying method, an aerosol deposition method, an aerosol gas deposition method, a powder jet deposition method, a particle jet deposition method, or a cold spray method), a PVD method (such as a sputtering method or a pulsed laser deposition method), or a CVD method. Whichever method is used, it is preferable to perform the formation at a temperature of 1100°C or less to prevent deterioration of the first plate-like body 1.

[0155] In this manner, the electrochemical reaction section 3 can be manufactured.

[0156] The electrochemical reaction unit 3 may be configured without either or both of the intermediate layer 34 and the reaction prevention layer 35. That is, the electrode layer 31 and the electrolyte layer 32 may be formed in contact with each other, or the electrolyte layer 32 and the counter electrode layer 33 may be formed in contact with each other. In this case, the intermediate layer forming step and the reaction prevention layer forming step are omitted from the above-described manufacturing method. It is also possible to add a step of forming another layer or to stack multiple layers of the same type, but in either case, it is preferable to perform the process at a temperature of 1100°C or less.

[0157] (Electrochemical element stack) 4, the electrochemical element stack S is configured by stacking a plurality of electrochemical elements A in a predetermined stacking direction. Adjacent electrochemical elements A are arranged such that the plate-like support 10 constituting one electrochemical element A (first electrochemical element A) faces the plate-like support 10 constituting the other electrochemical element A (second electrochemical element A).

[0158] For example, one electrochemical element A (first electrochemical element A) comprises a plate-like support 10 having a first plate-like body 1 and a second plate-like body 2 on which an electrochemical reaction unit 3 is arranged. Similarly, the plate-like support 10 of a second electrochemical element A adjacent to the first electrochemical element A in the downward direction (first direction) and upward direction (second direction) also comprises a plate-like support 10 having a first plate-like body 1 and a second plate-like body 2 on which an electrochemical reaction unit 3 is arranged.

[0159] The outer surface of the second plate 2 of the first electrochemical element A is electrically connected to the outer surface of the first plate 1 of the upper adjacent second electrochemical element A. In addition, a flow section A2 through which the second gas flows is formed between the outer surface of the second plate 2 of the first electrochemical element A and the outer surface of the first plate 1 of the upper adjacent second electrochemical element A along both outer surfaces.

[0160] The outer surface of the first plate 1 of the first electrochemical element A is electrically connected to the outer surface of the second plate 2 of the adjacent second electrochemical element A. A sub-channel A11 (part of the internal channel A1) through which the first gas flows is formed between the outer surface of the first plate 1 of the first electrochemical element A and the outer surface of the second plate 2 of the adjacent second electrochemical element A. To achieve electrical connection, methods that can be used include simply contacting the electrically conductive surface portions, applying surface pressure to the contact surfaces, or inserting a highly electrically conductive material between them to reduce contact resistance.

[0161] A plurality of such electrochemical elements A are stacked. Specifically, the rectangular electrochemical elements are stacked in a state where the first through-hole 41 at one end and the second through-hole 51 at the other end are aligned, with the electrochemical reaction portion of each electrochemical element facing upward. A first annular seal portion 42 is interposed between each first through-hole 41, and a second annular seal portion 52 is interposed between each second through-hole 51.

[0162] The plate-shaped support 10 is provided with a first through-portion 41 at one longitudinal end of the rectangular plate-shaped support 10. The first through-portion 41 forms a supply path 4 for supplying a first gas, which is one of a reducing component gas and an oxidizing component gas, to the internal flow path A1 from the outer side in the surface penetration direction. Within the flow path A2, the first through-portions 41 formed on both outer surfaces of the plate-shaped support 10 are provided with a first annular seal portion 42 as an annular seal portion that separates the flow path A2. The first through-portion 41 and the first annular seal portion 42 form the supply path 4 for supplying the first gas to the internal flow path A1. An annular bulge portion a is provided on the surface of the first plate-shaped support 11 opposite the internal flow path A1 around the portion of the first plate-shaped support 1 that comes into contact with the first annular seal portion 42, making it easy to position the first annular seal portion 42 along the surface of the first plate-shaped support 1.

[0163] The plate-shaped support body 10 is also provided with second through-portions 51 at the other end thereof, which form an exhaust path 5 for exhausting the first gas that has flowed through the internal flow path A1 outward in the direction penetrating the surface of the plate-shaped support body 10. The second through-portions 51 are configured to allow the first gas to flow while being separated from the second gas. The second through-portions 51 are provided with second annular seal portions 52 as annular seal portions that separate the second through-portions 51 formed on both outer surfaces of the plate-shaped support body 10 from the flow-through portion A2, within the flow-through portion A2. The second through-portions 51 and the second annular seal portions 52 form an exhaust path 5 for exhausting the first gas that has flowed through the internal flow path A1.

[0164] The first annular seal portion 42 and the second annular seal portion 52 are made of an insulating material such as a ceramic material such as alumina, mica, or a metal coated with these, and function as insulating seal portions that electrically insulate adjacent electrochemical elements from each other.

[0165] (6) Energy systems, electrochemical devices Next, the energy system and the electrochemical device will be described with reference to FIG.

[0166] The energy system Z includes an electrochemical device 100 and a heat exchanger 190 as a waste heat utilization section that reuses heat discharged from the electrochemical device 100.

[0167] The electrochemical device 100 has an electrochemical module M, a fuel converter consisting of a desulfurizer 101 and a reformer 102, a fuel supply unit 103 that supplies fuel gas containing a reducing component to the electrochemical module M, and an inverter (an example of a power converter) 104 as an output unit 8 that extracts electricity from the electrochemical module M.

[0168] Specifically, the electrochemical device 100 includes a desulfurizer 101, a reforming water tank 105, a vaporizer 106, a reformer 102, a blower 107, a combustion unit 108, an inverter 104, a control unit 110, and an electrochemical module M.

[0169] The desulfurizer 101 removes (desulfurizes) sulfur compounds contained in hydrocarbon raw fuel such as city gas. When sulfur compounds are contained in the raw fuel, the provision of the desulfurizer 101 can suppress adverse effects of the sulfur compounds on the reformer 102 or the electrochemical device A. The vaporizer 106 generates steam from reforming water supplied from the reforming water tank 105. The reformer 102 uses the steam generated in the vaporizer 106 to steam reform the raw fuel desulfurized in the desulfurizer 101, generating a reformed gas containing hydrogen.

[0170] The electrochemical module M generates electricity by electrochemical reaction using the reformed gas supplied from the reformer 102 and the air supplied from the blower 107. The combustion section 108 mixes the reaction exhaust gas discharged from the electrochemical module M with air and combusts combustible components in the reaction exhaust gas.

[0171] The inverter 104 adjusts the output power of the electrochemical module M to the same voltage and frequency as electricity received from a commercial grid (not shown). The control unit 110 controls the operation of the electrochemical device 100 and the energy system Z.

[0172] The reformer 102 performs a reforming process on the raw fuel using the combustion heat generated by the combustion of the reaction exhaust gas in the combustion section 108 .

[0173] The raw fuel is supplied to the desulfurizer 101 through a raw fuel supply path 112 by operation of a booster pump 111. The reforming water in the reforming water tank 105 is supplied to the vaporizer 106 through a reforming water supply path 114 by operation of a reforming water pump 113. The raw fuel supply path 112 merges with the reforming water supply path 114 at a location downstream of the desulfurizer 101, and the merged reforming water and raw fuel are supplied to the vaporizer 106.

[0174] The reforming water is vaporized in the vaporizer 106 to become water vapor. The raw fuel containing water vapor produced in the vaporizer 106 is supplied to the reformer 102 through a water vapor-containing raw fuel supply path 115. The raw fuel is steam reformed in the reformer 102 to produce a reformed gas (first gas having a reducing component) mainly composed of hydrogen gas. The reformed gas produced in the reformer 102 is supplied to the electrochemical module M through a fuel supply unit 103.

[0175] The reaction exhaust gas is combusted in the combustion section 108 to become a combustion exhaust gas, which is sent from the combustion exhaust gas discharge path 116 to the heat exchanger 190. A combustion catalyst section 117 (e.g., a platinum-based catalyst) is arranged in the combustion exhaust gas discharge path 116, and reduces the carbon monoxide, hydrogen, and other reducing components contained in the combustion exhaust gas by combustion.

[0176] The heat exchanger 190 exchanges heat between the combustion exhaust gas generated by combustion in the combustion unit 108 and the supplied cold water to generate hot water. In other words, the heat exchanger 190 operates as a waste heat utilization unit that reuses the heat discharged from the electrochemical device 100.

[0177] Instead of the exhaust heat utilization section, a reaction exhaust gas utilization section may be provided that utilizes the reaction exhaust gas discharged (without being combusted) from the electrochemical module M. Also, at least a portion of the reaction exhaust gas circulating from the first gas discharge section 62 to the outside of the container 200 may be recycled by joining it with any of the locations 100, 101, 103, 106, 112, 113, and 115 in FIG. 16. The reaction exhaust gas contains residual hydrogen gas that was not used in the reaction in the electrochemical device A. In the reaction exhaust gas utilization section, the residual hydrogen gas is utilized for heat utilization by combustion or for power generation using a fuel cell or the like, thereby making effective use of energy.

[0178] Other Embodiments The configurations disclosed in the above-described embodiments (including other embodiments, the same applies below) can be applied in combination with configurations disclosed in other embodiments, as long as no contradictions arise. Furthermore, the embodiments disclosed in this specification are examples, and the embodiments of the present invention are not limited to these, and can be modified as appropriate within the scope that does not deviate from the purpose of the present invention.

[0179] (1) In the above-described embodiment, the current collector 81 includes one supply pipe member 81c and one discharge pipe member 81d. The current collector 81 may include multiple supply pipe members 81c. The current collector 81 may include multiple discharge pipe members 81d. A configuration in which the current collector 81 includes only the supply pipe member 81c is also possible. A configuration in which the current collector 81 includes only the discharge pipe member 81d is also possible.

[0180] The current collector 82 may include one or more supply pipe members 81c. The current collector 82 may include one or more discharge pipe members 81d.

[0181] (2) The current collector 81 (and / or the current collector 82) may include a pipe member through which a second gas, which is the other of the reducing component gas and the oxidizing component gas, flows. Specifically, the current collector 81 (and / or the current collector 82) may include one or both of a supply pipe member that supplies the second gas to the electrochemical element A and a discharge pipe member that discharges the second gas from the electrochemical element A.

[0182] (3) A member functioning as a separator (e.g., second plate 2) and a current collector may be integrated by welding. For example, in the example of Fig. 4, the second plate 2 of the electrochemical element A at the bottom in the drawing may be integrated with the current collector plate 82a of the current collector 82 by welding.

[0183] (4) In the above embodiment, two embossed portions 15 are formed on the first plate-like body 1. One or three or more embossed portions 15 may be formed on the first plate-like body 1. One or more embossed portions recessed toward the internal flow path A1 may be formed on the second plate-like body 2. Embossed portions may be formed on both the first plate-like body 1 and the second plate-like body 2.

[0184] (5) In the above-described embodiment, through holes 16 are formed through the first plate-like body 1 and the second plate-like body 2 at positions corresponding to the bottoms 15a of the embossed portions 15. A configuration in which no through holes 16 are formed is also possible. Embossed portions 15 with through holes 16 formed and embossed portions 15 without through holes 16 may be mixed.

[0185] (6) In the above embodiment, the electrochemical element A is used in a solid oxide fuel cell as the electrochemical device 100, but the electrochemical element A can also be used in a solid oxide electrolysis cell, an oxygen sensor using a solid oxide, etc. Furthermore, the electrochemical element A can be used alone, not limited to being used in combination as the electrochemical element stack S or the electrochemical module M. That is, in the above embodiment, a configuration has been described that can improve the efficiency of converting chemical energy such as fuel into electrical energy. That is, in the above embodiment, the electrochemical device A and the electrochemical module M are operated as a fuel cell, and hydrogen gas is passed through the electrode layer 31, and oxygen gas is passed through the counter electrode layer 33. Then, oxygen molecules O2 are converted into electrons e - reacts with oxygen ions O 2- The oxygen ions O 2- moves through the electrolyte layer 32 to the electrode layer 31. In the electrode layer 31, hydrogen molecules H2 are converted into oxygen ions O 2- reacts with water H2O and electrons e - The above reaction generates an electromotive force between the electrode layer 31 and the counter electrode layer 33, generating electricity. On the other hand, when the electrochemical device A and the electrochemical module M are operated as an electrolysis cell, a gas containing water vapor and carbon dioxide is passed through the electrode layer 31, and a voltage is applied between the electrode layer 31 and the counter electrode layer 33. Then, electrons e - reacts with water molecules H2O and carbon dioxide molecules CO2 to produce hydrogen molecules H2, carbon monoxide CO, and oxygen ions O 2- Oxygen ions O 2- moves through the electrolyte layer 32 to the counter electrode layer 33. In the counter electrode layer 33, oxygen ions O 2- releases electrons and becomes oxygen molecules O2. Through the above reaction, water molecules H2O are electrolyzed into hydrogen H2 and oxygen O2, and when gas containing carbon dioxide molecules CO2 is circulated, it is electrolyzed into carbon monoxide CO and oxygen O2. When gas containing water vapor and carbon dioxide molecules CO2 is circulated, a fuel converter 25 (FIG. 17) can be provided to synthesize various compounds such as hydrocarbons from the hydrogen and carbon monoxide produced by the electrolysis in the electrochemical element A and electrochemical module M. The hydrocarbons produced by the fuel converter 25 can be circulated to the electrochemical element A and electrochemical module M by a fuel supply unit (not shown), or can be taken out of the system / device and used as a separate fuel or chemical raw material.

[0186] FIG. 17 shows an example of an energy system Z and an electrochemical device 100 in which the electrochemical reaction unit 3 operates as an electrolysis cell. In this system, supplied water and carbon dioxide are electrolyzed in the electrochemical reaction unit 3 to produce hydrogen, carbon monoxide, and the like. Hydrocarbons and the like are then synthesized in the fuel converter 25. Energy efficiency can be improved by configuring the heat exchanger 24 in FIG. 17 to operate as a waste heat utilization unit that exchanges heat between the reaction heat generated by the reaction in the fuel converter 25 and water to vaporize it, and the heat exchanger 23 in FIG. 17 to operate as a waste heat utilization unit that exchanges heat between the waste heat generated by the electrochemical element A and water vapor and carbon dioxide to preheat them. Furthermore, the power converter 93 supplies power to the electrochemical device A. As a result, the electrochemical device A functions as an electrolytic cell as described above. Therefore, with the above configuration, it is possible to provide the electrochemical device 100, the energy system Z, and the like that can improve the efficiency of converting electrical energy into chemical energy such as fuel.

[0187] (7) In the above embodiment, the material of the electrode layer 31 is, for example, NiO. - GDC, Ni - GDC, NiO - YSZ, Ni - YSZ, CuO - CeO2, Cu - A composite material such as CeO2 is used, and a composite oxide such as LSCF or LSM is used as the material for the counter electrode layer 33. The electrochemical element A configured in this manner can be used as a solid oxide fuel cell by supplying hydrogen gas to the electrode layer 31 to make it a fuel electrode (anode) and supplying air to the counter electrode layer 33 to make it an air electrode (cathode). This configuration can also be modified to configure the electrochemical element A so that the electrode layer 31 can be used as an air electrode and the counter electrode layer 33 can be used as a fuel electrode. That is, a composite oxide such as LSCF or LSM is used as the material for the electrode layer 31, and a composite oxide such as NiO is used as the material for the counter electrode layer 33. - GDC, Ni - GDC, NiO - YSZ, Ni - YSZ, CuO - CeO2, Cu - A composite material such as CeO2 is used. In the electrochemical element A configured in this manner, air is supplied to the electrode layer 31 to make it an air electrode, and hydrogen gas is supplied to the counter electrode layer 33 to make it a fuel electrode, so that the electrochemical element A can be used as a solid oxide fuel cell.

[0188] (8) In the above embodiment, the electrode layer 31 is disposed between the first plate 1 and the electrolyte layer 32, and the counter electrode layer 33 is disposed on the opposite side of the electrolyte layer 32 from the first plate 1. A configuration in which the electrode layer 31 and the counter electrode layer 33 are disposed in reverse is also possible. That is, a configuration in which the counter electrode layer 33 is disposed between the first plate 1 and the electrolyte layer 32, and the electrode layer 31 is disposed on the opposite side of the electrolyte layer 32 from the first plate 1 is also possible. In this case, the supply of gas to the electrochemical device A must also be changed.

[0189] That is, various configurations can be adopted for the order of the electrode layer 31 and the counter electrode layer 33 and whether the first gas or the second gas is one or the other of the reducing component gas and the oxidizing component gas, as long as the first gas and the second gas are supplied to the electrode layer 31 and the counter electrode layer 33 in a manner that allows them to react appropriately.

[0190] (9) In the above embodiment, the electrochemical reaction unit 3 is provided on the side of the first plate 1 opposite the second plate 2, covering the gas flow-permitting unit 1A. However, the electrochemical reaction unit 3 may be provided on the side of the first plate 1 facing the second plate 2. In other words, the present invention is valid even if the electrochemical reaction unit 3 is configured to be disposed in the internal flow path A1.

[0191] (10) In the above embodiment, the first through portion 41 and the second through portion 51 are provided in pairs at both ends of the rectangular plate-like support body, but they are not limited to being provided at both ends, and two or more pairs may be provided. Also, the first through portion 41 and the second through portion 51 do not have to be provided in pairs. Therefore, one or more first through portion 41 and one or more second through portion 51 may be provided.

[0192] Furthermore, the plate-like support is not limited to a rectangular shape, and various shapes such as a square shape and a circular shape can be adopted.

[0193] (11) In the above description, the lower cover 203 and the upper cover 201 are joined by welding. However, the joining of the lower cover 203 and the upper cover 201 is not limited to welding, and they may be joined by, for example, bolts or the like.

[0194] (12) In the above description, the opening 201c is formed in the upper cover 201, and the opening 203c is formed in the lower cover 203. However, the openings 201c and 203c do not necessarily have to be formed.

[0195] (13) In the above, the electrochemical element stack S is sandwiched between the container 200 (first sandwiching body, second sandwiching body). However, if the electrochemical element stack S can be sandwiched, there is no need to use the container 200. For example, the electrochemical element stack S may be sandwiched between end plates (first sandwiching body, second sandwiching body) or the like.

[0196] (14) The first annular seal portion 42 and the second annular seal portion 52 may have any shape as long as they are configured to connect the first through-holes 41 and the second through-holes 51 to each other and prevent gas leakage. In other words, the first annular seal portion 42 and the second annular seal portion 52 may have an endless configuration with openings therein that communicate with the through-holes and be configured to seal between adjacent electrochemical elements A. The first annular seal portion 42 and the second annular seal portion 52 may be, for example, annular. The annular shape may be any shape, such as circular, elliptical, rectangular, or polygonal.

[0197] (15) In the above, the plate-like support 10 is composed of a first plate-like body 1 and a second plate-like body 2. Here, the first plate-like body 1 and the second plate-like body 2 may be composed of separate plate-like bodies, or may be composed of a single plate-like body. In this case, the first plate-like body 1 and the second plate-like body 2 are overlapped by bending the single plate-like body. Then, the first plate-like body 1 and the second plate-like body 2 are integrated by welding the peripheral edge portion 1a or the like. Note that the first plate-like body 1 and the second plate-like body 2 may be composed of a series of seamless plate-like bodies, or may be formed by bending a series of plate-like bodies.

[0198] (16) In the above embodiment, the electrochemical device includes an electrochemical module M including a plurality of electrochemical elements A. However, the electrochemical device of the above embodiment can also be applied to a configuration including one electrochemical element. [Explanation of symbols]

[0199] 1: First plate-like body (support) 2: Second plate-shaped body (separator) 2a: Apex part 3: Electrochemical reaction section 25: Fuel converter 92: Flat plate structure 93: Power converter 100: Electrochemical device 103:Fuel supply section A: Electrochemical element A1: Internal flow path A11: Sub-channel A12:Distribution section A13: Merging section S: Electrochemical element laminate Z: Energy System

Claims

1. An electrochemical element stack in which an electrochemical reaction unit to which a first gas and a second gas are supplied, a support supporting the electrochemical reaction unit, and a separator separating a flow path for the first gas from a flow path for the second gas are stacked in a state in which a load is applied in the stacking direction, The electrochemical element stack includes a flat plate-like structure disposed between the support and the separator, and capable of applying a load from one of the support and the separator to the other.

2. 2. The electrochemical element stack according to claim 1, wherein the flat plate-like structures are electrically conductive.

3. 2. The electrochemical element laminate according to claim 1, wherein the flat plate-like structures are made of metal.

4. 4. The electrochemical element laminate according to claim 3, wherein the flat plate-like structures are made of Ni or stainless steel.

5. 4. The electrochemical element laminate according to claim 3, wherein the flat plate-like structure is a metal mesh or lath metal.

6. 2. The electrochemical element stack according to claim 1, wherein the flat plate-like structures extend in the longitudinal direction up to the vicinity of the longitudinal end of the electrochemical reaction section.

7. 2. The electrochemical element laminate according to claim 1, wherein the thickness of the flat plate-like structure is 80% or more of the distance between the support and the separator.

8. the support body and the separator are plate-shaped, and the support body and the separator are joined to form an internal flow path for the first gas between opposing surfaces of the support body and the separator; 2. The electrochemical element stack according to claim 1, wherein the flat plate-like structure is disposed in the internal flow path.

9. the internal flow path includes a plurality of sub-flow paths, a distribution section that distributes gas to the sub-flow paths, and a confluence section where gases from the sub-flow paths converge; The separator is formed in a corrugated shape, and peaks of the waves divide the sub-flow paths, 9. The electrochemical element stack according to claim 8, wherein the longitudinal ends of the flat plate-like structures are located more inward than the longitudinal ends of the vertices.

10. 10. An electrochemical device comprising at least the electrochemical element stack according to claim 1 and a fuel converter, and a fuel supply unit that supplies a reducing component gas from the fuel converter to the electrochemical element stack, or that supplies a reducing component gas from the electrochemical element stack to the fuel converter.

11. 10. An electrochemical device comprising at least the electrochemical element stack according to claim 1 and a power converter that extracts electric power from the electrochemical element stack or passes electric power through the electrochemical element stack.

12. 11. An energy system comprising: the electrochemical device according to claim 10; and a waste heat utilization section that reuses heat discharged from the electrochemical device or a fuel converter.

13. An energy system comprising: the electrochemical device according to claim 11; and a waste heat utilization section that reuses heat discharged from the electrochemical device.

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