Electrochemical cells, electrochemical cell stacks, hot modules, and electrolytic reactors

Abstract

The present invention provides an electrochemical cell capable of preventing or suppressing the delamination of the fuel electrode layer from the metal support. [Solution] The electrochemical cell 10 comprises an electrolyte layer 13, an air electrode layer 14 laminated on one surface of the electrolyte layer 13, a fuel electrode layer 12 laminated on the other surface of the electrolyte layer 13, and a metal support 11 laminated on the surface of the fuel electrode layer 12 opposite to the side facing the electrolyte layer 13. The metal support 11 has a plurality of through holes 113 that connect a first surface 111 facing the fuel electrode layer 12 and a second surface 112 opposite to the first surface 111. The inner circumferential surface of at least one through hole 113 has a rough portion 114 and a smooth portion 115 with different arithmetic mean roughness, the smooth portion 115 is provided between the rough portion 114 and the first surface 111, and the fuel electrode layer 12 has an overlapping portion 122 that covers the rough portion 114.

Description

Technical Field

[0001] The present disclosure relates to an electrochemical cell, an electrochemical cell stack, a hot module, and an electrolysis reaction device.

Background Art

[0002] Conventionally, an electrochemical cell capable of producing hydrogen by electrolyzing water (steam), and an electrochemical cell capable of generating electricity by reacting hydrogen and oxygen are known. Such an electrochemical cell includes an electrolyte layer (solid electrolyte layer) containing a solid oxide, a fuel electrode layer laminated on one surface of the electrolyte layer, and an air electrode layer laminated on the other surface of the electrolyte layer. As one type of the above-described electrochemical cell, a metal-supported electrochemical cell is known. The metal-supported electrochemical cell includes a flat metal support, and the metal support supports the electrolyte layer, the fuel electrode layer, and the air electrode layer.

[0003] Patent Document 1 discloses a configuration for suppressing peeling of the fuel electrode layer from the metal support, in which a film formed by oxidation provided on the metal support has a protruding film portion that protrudes into the main body portion (a laminate of the electrolyte layer, the fuel electrode layer, and the air electrode layer) of the electrochemical cell. And Patent Document 1 discloses that peeling of the cell main body portion from the metal support is suppressed by the anchor effect of this protruding film portion. Thus, in a metal-supported electrochemical cell, when a force is applied to the electrochemical cell, it is required that the electrolyte layer, the fuel electrode layer, and the air electrode layer do not peel from the metal support.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] This disclosure aims to solve the problems described above. Specifically, one of the objectives of this disclosure is to provide an electrochemical cell (single cell) that can prevent or suppress the delamination of the fuel electrode layer from the metal support, an electrochemical cell stack equipped with such an electrochemical cell, a hot module equipped with this electrochemical cell stack, and an electrolytic reactor equipped with this hot module.

[0006] To solve the above problems, the electrochemical cell relating to this disclosure is The device comprises an electrolyte layer, an air electrode layer laminated on one surface of the electrolyte layer, a fuel electrode layer laminated on the other surface of the electrolyte layer, and a plate-shaped metal support laminated on the surface of the fuel electrode layer opposite to the side facing the electrolyte layer. The metal support has a plurality of through holes that connect a first surface, which is the surface facing the fuel electrode layer, and a second surface, which is the surface opposite to the first surface. The inner circumferential surface of at least one of the through holes is A rough portion and provided between the rough portion and the first surface Arithmetic mean roughness of at least one of the through holes in the direction of penetration but is smaller than the aforementioned coarse part It comprises a smooth section, The opening area of ​​the end of the rough portion near the second surface in at least one of the through holes provided in the metal support is larger than the opening area of ​​the end of the rough portion near the first surface. The fuel electrode layer comprises an overlapping portion having a portion that covers the rough portion of at least one of the through holes.

[0007] The gas flow rate inside the through-holes in the metal support tends to be lower than that on the back surface of the metal support. Therefore, it is necessary to facilitate gas flow into the reaction field at the electrolyte-electrode interface. For this reason, it is preferable that the inner circumferential surface of the through-hole be smooth (a structure that does not hinder gas retention). However, if a portion of the fuel electrode is located inside the through-hole, it is necessary to prevent or suppress delamination of the fuel electrode. If the through-hole is provided with a smooth portion, the side surface of the hole at the electrolyte-electrode interface, where gas flow is difficult, will have a smooth portion, which can increase gas flow rate. Furthermore, if the through-hole is provided with a rough portion, the anchoring effect between the superimposed portion of the fuel electrode layer and the rough portion of the inner circumferential surface of the through-hole will be increased, thereby increasing the bonding strength between the fuel electrode layer and the metal support. Therefore, it is possible to prevent or suppress delamination of the fuel electrode layer from the metal support in an electrochemical cell. Thus, according to this disclosure, by having a rough surface on the back side of the metal support, where gas flow is easily facilitated, a structure that combines gas flow rate inside the hole with electrode adhesion can be created. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic perspective view showing the configuration of an electrochemical cell. [Figure 2] Figure 2 is a cross-sectional view taken along the line II-II in Figure 1. [Figure 3A] Figure 3A is a cross-sectional view showing the configuration of the through-holes in the metal support and the superimposed portion of the fuel electrode layer. [Figure 3B] Figure 3B is a cross-sectional view showing the configuration of the through-holes in the metal support and the superimposed portion of the fuel electrode layer. [Figure 3C] Figure 3C is a cross-sectional view showing the configuration of the through-holes in the metal support and the superimposed portion of the fuel electrode layer. [Figure 3D] Figure 3D is a cross-sectional view showing the configuration of the through-holes in the metal support and the superimposed portion of the fuel electrode layer. [Figure 4] Figure 4 is a perspective view showing the configuration of an electrochemical cell stack. [Figure 5A] Figure 5A is a cross-sectional view showing the configuration of an electrochemical cell stack. [Figure 5B]Figure 5B is a cross-sectional view showing the configuration of an electrochemical cell stack. [Figure 6] Figure 6 is a block diagram of the electrolytic reaction apparatus. [Modes for carrying out the invention]

[0009] <Electrochemical cell> First, the electrochemical cell 10 (single cell) according to this embodiment will be described. The electrochemical cell 10 according to this embodiment is a component (element) configured to produce hydrogen and oxygen by electrolysis (co-electrolysis) of water vapor (water).

[0010] Figure 1 is a schematic perspective view showing the configuration of the electrochemical cell 10 according to this embodiment. Figure 2 is a cross-sectional view taken along the line II-II in Figure 1, which schematically shows the structure of a part of the cross-section of the electrochemical cell 10. In each figure, the upper side of the electrochemical cell 10 is indicated by the arrow Up, and the lower side is indicated by the arrow Dw. The electrochemical cell 10 has a roughly quadrilateral flat plate shape. As shown in Figures 1 and 2, the electrochemical cell 10 includes a metal support 11, a fuel electrode layer 12 (fuel electrode active layer), an electrolyte layer 13, and an air electrode layer 14. The metal support 11, fuel electrode layer 12, electrolyte layer 13, and air electrode layer 14 are stacked in that order from one side in the thickness direction of the electrochemical cell 10 (the lower side in this embodiment).

[0011] The metal support 11 is a roughly quadrilateral, flat plate-shaped member made of metal. For example, ferritic stainless steel (SUS) can be used for the metal support 11. The metal support 11 is arranged so that its thickness direction is parallel to the vertical direction (the stacking direction of the metal support 11, fuel electrode layer 12, electrolyte layer 13, and air electrode layer 14). In this embodiment, one surface of the metal support 11 in the thickness direction that faces the electrolyte layer 13 is sometimes referred to as the first surface 111 (top surface in this embodiment), and the surface opposite the first surface 111 (bottom surface in this embodiment) is sometimes referred to as the second surface 112 to distinguish them. The metal support 11 is provided with a plurality of through holes 113 that penetrate in the thickness direction and through which the fuel electrode gas, which will be described later, can pass. The plurality of through holes 113 can also be said to be holes that connect the first surface 111 and the second surface 112 of the metal support 11. The configuration of the through holes 113 will be described later.

[0012] The fuel electrode layer 12 is a layer mainly composed of a cermet of Ni and an ion-conducting oxide (in this embodiment, YSZ (yttria-stabilized zirconia)). Furthermore, the fuel electrode layer 12 is a porous layer configured to be porous, containing a plurality of micropores (not shown). However, the components of the fuel electrode layer 12 are not limited to those described above. For example, the main components of the fuel electrode layer 12 can be Ni and GDC (gadolinia-doped ceria).

[0013] The fuel electrode layer 12 may also be provided with an adhesive layer for bonding to the metal support 11 or for improving the bonding strength with the metal support 11. The adhesive layer is a conductive and gas-permeable layer. The adhesive layer of the fuel electrode layer 12 may be formed from a different material than the parts of the fuel electrode layer 12 other than the adhesive layer (fuel electrode active layer). Examples of materials that can be used as the adhesive layer of the fuel electrode layer 12 include a composite material of Ni-YSZ and a metal oxide, a composite material of YSZ and a metal oxide, a spinel-type oxide, or a ceria-based material. The composite material of Ni-YSZ and a metal oxide is a component in which Ni-YSZ is mixed with an oxide of the metal support 11 (ferritic stainless steel) (e.g., Cr2O3, Mn3O4, etc.) and additives for adjusting the coefficient of thermal expansion. During sintering, the metal oxide reacts with Ni-YSZ, so it functions as a buffer layer between the parts of the fuel electrode layer 12 other than the adhesive layer (fuel electrode active layer). As a composite material of YSZ and metal oxides, materials can be applied in which the oxide of the metal support 11 or an oxide that acts as a sintering aid is added to the YSZ. By making the composition different from that of the adhesive layer and the part of the fuel electrode layer 12 other than the adhesive layer (fuel electrode active layer) (Ni-YSZ), a stress relaxation effect is achieved at the interface between the adhesive layer and the other part of the fuel electrode layer 12. As spinel-type oxides, CoCr2O4 and MnCo2O4 can be applied. Spinel-type oxides function as an intermediate layer because their coefficient of thermal expansion is close to that of metals. Examples of ceria-based materials include CeO2 and Gd-doped ceria (GDC). Ceria-based materials have oxide ion conductivity and high chemical stability. Furthermore, because their coefficient of thermal expansion is close to that of YSZ, delamination at the interface between the adhesive layer and the part of the fuel electrode layer 12 other than the adhesive layer is prevented or suppressed.

[0014] The fuel electrode layer 12 has one plate-shaped portion 121 and a plurality of overlapping portions 122. The plate-shaped portion 121 is a portion that is laminated (overlapped) on the first surface 111 of the metal support 11. The plate-shaped portion 121 has a substantially quadrilateral outer shape that is substantially the same as that of the metal support 11 when viewed in the thickness direction. Also, the plate-shaped portion 121 of the fuel electrode layer 12 is formed to be thicker than the electrolyte layer 13. Each overlapping portion 122 is a portion where at least a part thereof enters into the through-hole 113 of the metal support 11. Note that the configuration of the overlapping portion 122 will be described later. The one plate-shaped portion 121 and the plurality of overlapping portions 122 are integrally connected (it can also be said that they are integrally formed).

[0015] The electrolyte layer 13 is a layer (solid electrolyte layer) made of a solid oxide electrolyte. The electrolyte layer 13 is a substantially quadrilateral flat plate-shaped layer, is configured to contain YSZ (yttria-stabilized zirconia), and is formed by sintering. The electrolyte layer 13 has high oxide ion conductivity. The electrolyte layer 13 is a dense layer and is configured such that gas cannot pass through in the thickness direction. The electrolyte layer 13 is laminated on the surface of the metal support 11 of the fuel electrode layer 12 opposite to the side in contact with the first surface 111. Note that in a view in the thickness direction of the electrochemical cell 10, the outer shape of the electrolyte layer 13 substantially coincides with the outer shape of the plate-shaped portion 121 of the fuel electrode layer 12.

[0016] The air electrode layer 14 is configured to contain a perovskite-type oxide such as LSCF (lanthanum strontium cobalt ferrite) and is formed by sintering (firing). The air electrode layer 14 has a functional layer and a current collecting layer. The current collecting layer is thicker than the functional layer and is disposed on the upper surface of the functional layer. The air electrode layer 14 has high electron conductivity and collects electrons well in the current collecting layer. This air electrode layer 14 is a porous layer and has pores inside.

[0017] The air electrode layer 14 is laminated on one surface (the upper surface in this embodiment) of the electrolyte layer 13. The air electrode layer 14 is a substantially quadrilateral flat plate-like layer. The air electrode layer 14 has an outer dimension smaller than those of the electrolyte layer 13 and the fuel electrode layer 12 in the thickness direction view of the electrochemical cell 10, and is disposed at the central portion of the upper surface of the electrolyte layer 13. For this reason, the outer peripheral portion of the upper surface of the electrolyte layer 13 is exposed.

[0018] Next, the configurations of the through holes 113 of the metal support 11 and the overlapping portions 122 of the fuel electrode layer 12 according to each example and each modification will be described. FIGS. 3A to 3D are cross-sectional views schematically showing the configurations of the through holes 113 of the metal support 11 and the overlapping portions 122 of the fuel electrode layer 12 according to each example and each modification. Note that the cross-sectional shape (the shape in the thickness direction view) when the through hole 113 is cut by a plane perpendicular to the penetrating direction is not particularly limited. The through hole 113 may be a round hole, a polygonal hole, or a hole having a cross-sectional shape other than a circular or polygonal shape.

[0019] (First Example) FIG. 3A is a cross-sectional view showing the configuration of the through hole 113 of the metal support 11 and the overlapping portion 122 of the fuel electrode layer 12 according to the first example. As shown in FIG. 3A, the inner peripheral surface of the through hole 113 includes a rough portion 114 and a smooth portion 115. The rough portion 114 is a portion having a predetermined surface roughness. The surface roughness of the rough portion 114 and the surface roughness of the smooth portion 115 are different from each other. And the surface roughness of the rough portion 114 is larger (rougher) than the surface roughness of the smooth portion 115 and the surface roughness of the first surface 111 of the metal support 11. The smooth portion 115 is a portion provided between the first surface 111 of the metal support 11 and the rough portion 114. The surface roughness of the smooth portion 115 is less than the surface roughness of the rough portion 114 and is greater than or equal to the surface roughness of the first surface 111 of the metal support 11. However, it is preferable that the surface roughness of the smooth portion 115 is larger than the surface roughness of the first surface 111 of the metal support 11. In this embodiment, the arithmetic mean roughness (Ra) is applied as the surface roughness.

[0020] For example, the arithmetic mean roughness of the first surface 111 of the metal support 11 is preferably 0.3 μm or more and 3.0 μm or less. That is, making the arithmetic mean roughness of the first surface 111 less than 0.3 μm would lead to an increase in cost. Also, from the viewpoint of adhesion with the fuel electrode layer 12, it is preferable for the arithmetic mean roughness of the first surface 111 to be large. However, the arithmetic mean roughness of the first surface 111 affects the characteristics of the fuel electrode layer 12 laminated on the first surface 111. For this reason, it is preferable for the arithmetic mean roughness of the first surface 111 to be 3.0 μm or less.

[0021] The arithmetic mean roughness of the coarse portion 114 is preferably 3.2 μm or more and 12.5 μm or less. If the arithmetic mean roughness of the coarse portion 114 is less than 3.2 μm, the anchoring effect between the coarse portion 114 and the overlapping portion 122 of the fuel electrode layer 12 becomes small, so the effect of preventing or suppressing delamination of the fuel electrode layer 12 is not obtained or the effect is low. On the other hand, if the arithmetic mean roughness of the coarse portion 114 is greater than 12.5 μm, the material of the fuel electrode layer 12 will not spread over a wide area of ​​the coarse portion 114 when forming the overlapping portion 122.

[0022] The arithmetic mean roughness of the smooth portion 115 is preferably 0.8 μm or more and less than 3.2 μm. Making the arithmetic mean roughness of the smooth portion 115 less than 0.8 μm would increase costs. If the arithmetic mean roughness of the smooth portion 115 is 3.2 μm or more, the material of the fuel electrode layer 12 will have difficulty reaching the rough portion 114 beyond the smooth portion 115 when forming the superimposed portion 122. As mentioned above, the surface roughness of the smooth portion 115 is equal to or greater than the surface roughness of the first surface 111 of the metal support 11. Therefore, if the arithmetic mean roughness of the first surface 111 is 0.8 μm or more, the arithmetic mean roughness of the smooth portion 115 will be equal to or greater than the arithmetic mean roughness of the first surface 111, within the range of 0.8 to 3.2 μm.

[0023] The rough portion 114 is provided on the side closer to the second surface 112 than the smooth portion 115. The cross-sectional dimension of the end of the rough portion 114 closer to the second surface 112 is larger than the cross-sectional dimension of the end closer to the first surface 111 (which can also be said to be the end closer to the smooth portion 115). Note that "cross-sectional dimension" is the dimension in the direction perpendicular to the through-hole 113's through-hole direction (approximately vertical direction). If the through-hole 113 is a round hole, its inner diameter is the cross-sectional dimension of the through-hole 113, and if the through-hole 113 is a square hole, the distance between the two opposing surfaces is the cross-sectional dimension. It is preferable that the cross-sectional dimension of the rough portion 114 gradually (continuously or in stages) increases from the end closer to the first surface 111 to the end closer to the second surface 112. However, the configuration of the rough portion 114 is not limited to this configuration. As described above, the rough portion 114 only needs to have a configuration in which the cross-sectional dimension of the end closer to the second surface 112 is larger than the cross-sectional dimension of the end closer to the first surface 111. Therefore, the rough portion 114 may locally contain "a portion whose cross-sectional dimension is smaller than the cross-sectional dimension of the end on the side closer to the first surface 111."

[0024] As a method for forming a through hole 113 with such a configuration, for example, punching (pressing) using a punch and die can be applied. If the through hole 113 is formed by punching, then on the inner circumferential surface of the through hole 113, a "shear surface" and a "fracture surface" are formed in order from one surface in the thickness direction of the metal plate, which is the material of the metal support 11, on the surface that the punch contacts (first surface 111). The "shear surface" is a smooth surface created when the die penetrates into the interior of the material. The "fracture surface" is a rough surface formed when cracks that originate in the material from the corners of the punch and the corners of the die connect with each other. In this case, the shear surface is the smooth part 115, and the fracture surface is the rough part 114.

[0025] Furthermore, in a view in the direction of punch movement (view in the thickness direction of the metal plate, which is the material of the metal support 11), the dimensions and shape of the starting point of a crack originating from the corner of the punch are approximately the same as the external shape and dimensions of the punch. Similarly, in a view in the direction of punch movement, the dimensions and shape of the starting point of a crack originating from the corner of the die are approximately the same as the shape and dimensions of the inner periphery of the opening (hole into which the punch enters) provided in the die. Since the dimensions of the opening of the die are larger than the external dimensions of the punch, in a view in the direction of punch movement, the starting point of a crack originating from the die is located further out than the starting point of a crack originating from the punch. Therefore, by placing the die on the second surface 112 side of the metal plate, which is the material of the metal support 11, and punching from the first surface 111 side, a rough portion 114 can be formed having the configuration that "the cross-sectional dimensions of the end closer to the second surface 112 are larger than the cross-sectional dimensions of the end closer to the first surface 111." The arithmetic mean roughness and cross-sectional dimensions of the smooth portion 115 and the rough portion 114 can be specified by appropriately setting the processing conditions (clearance between punch and die, processing speed, etc.).

[0026] To determine the arithmetic mean roughness of the rough portion 114 and the smooth portion 115, the following method can be applied, for example. First, the inside of the through hole 113 is filled with resin or the like. Then, the metal support 11 is cut with a plane that is parallel to the through-direction of the through hole 113 (the vertical direction in this embodiment) and passes through the center of the through hole 113 (the centroid of the through hole 113 when viewed in the vertical direction). If the through hole 113 is a round hole, it is cut with a plane that passes through the center of the circle, or the resin filled inside the metal support 11 and the through hole 113 is ground so that a cross-section passing through the center of the circle appears. Then, the cross-section revealed by cutting or grinding is photographed with an SEM to obtain an SEM image of the cross-section. Next, by image analysis of the SEM image, a curve that is the interface between the metal support 11 and the resin or fuel electrode (or the interface between the metal support 11 and the fuel electrode layer 12) is extracted, and the arithmetic mean roughness of the extracted curve is calculated based on the JIS standard. In this case, the arithmetic mean roughness of two opposing curves on either side of the center of the through hole 113 is obtained for both the rough portion 114 and the smooth portion 115. The average of these two arithmetic mean roughnesses is then taken as the arithmetic mean roughness of the rough portion 114 and the smooth portion 115, respectively. This provides the arithmetic mean roughness of the rough portion 114 and the smooth portion 115 in the through-direction of the through hole 113, as well as the arithmetic mean roughness of the first surface 111.

[0027] As shown in Figure 3A, the overlapping portion 122 has a bottomed cylindrical structure with an open end on the side closer to the second surface 112. At least a portion of the overlapping portion 122 is in contact with at least a portion of the rough portion 114 on the inner surface of the through hole 113. In other words, the overlapping portion 122 has a portion that contacts the rough portion 114 on the inner surface of the through hole 113. With this configuration, the anchoring effect between the overlapping portion 122 of the fuel electrode layer 12 and the rough portion 114 on the inner surface of the through hole 113 increases the bonding strength between the fuel electrode layer 12 and the metal support 11. In particular, if the surface roughness (arithmetic mean roughness in this embodiment) of the rough portion 114 is greater than the surface roughness of the smooth portion 115 and also greater than the surface roughness of the first surface 111, the bonding strength becomes greater than that between the plate-like portion 121 of the fuel electrode layer 12 and the metal support 11. Therefore, it is possible to prevent or suppress the delamination of the fuel electrode layer 12 from the metal support 11.

[0028] Thus, when the inner circumferential surface of the through hole 113 has a rough portion 114, the overlapping portion 122 of the fuel electrode layer 12 has a portion that contacts the rough portion 114 of the through hole 113, thereby enhancing the anchoring effect in that portion. This makes it possible to prevent or suppress delamination of the fuel electrode layer 12 from the metal support 11. Furthermore, by having a cylindrical structure in which the tip end is open, it is possible to prevent or suppress the tip end of the overlapping portion 122 (first overlapping portion 123) from becoming the starting point of delamination, thereby enhancing the effect of preventing or suppressing delamination of the fuel electrode layer 12 from the metal support 11.

[0029] Furthermore, the opening area at the end of the through-hole 113 closest to the second surface 112 is larger than the opening area at the end closest to the first surface 111. With this configuration, the fuel electrode gas, which will be described later, flows more easily into the through-hole 113 from the second surface 112 side. As a result, it becomes easier to supply the fuel electrode gas to the reaction field (near the interface between the fuel electrode layer 12 and the electrolyte layer 13) from the second surface 112 side of the metal support 11, thereby promoting the reaction in the reaction field.

[0030] In other words, the gas flow rate inside the through-hole 113 provided in the metal support 11 tends to be lower than that on the second surface 112 side of the metal support 11. Therefore, it is necessary to facilitate the passage of gas into the reaction field between the electrolyte layer 13 and the fuel electrode layer 12. For this reason, it is preferable that the inner circumferential surface of the through-hole 113 be smooth (a structure that does not hinder gas retention). On the other hand, as described above, if a part of the fuel electrode layer 12 is located inside the through-hole 113, it is necessary to prevent or suppress the peeling of the fuel electrode layer 12. If a smooth portion 115 is provided in the through-hole 113, the gas flow rate at and near the interface between the electrolyte layer 13 and the fuel electrode layer 12, where gas flow is difficult, can be increased. Therefore, a structure can be created that combines gas flow rate inside the through-hole 113 with good adhesion between the fuel electrode layer 12 and the metal support 11.

[0031] The thickness of the overlapping portion 122 at the end on the first surface 111 side, which is a dimension in a direction approximately perpendicular to the through-hole 113's penetration direction, is greater than the thickness at the end on the second surface 112 side. With this configuration, delamination starting from the end on the second surface 112 side can be prevented or suppressed. That is, when the overlapping portion 122 attempts to deform (for example, shrink) in the through-hole 113's penetration direction, a shear force is generated between the overlapping portion 122 and the rough portion 114 of the through-hole 113 due to the bonding force between the outer circumferential surface of the overlapping portion 122 and the inner circumferential surface of the through-hole 113.

[0032] Furthermore, if this shear force becomes large, there is a risk that the overlapping portion 122 will peel off from the inner circumferential surface of the through hole 113. However, this shear force decreases as the cross-sectional area of ​​the overlapping portion 122 (the cross-sectional area when cut by a plane perpendicular to the axial direction of the through hole 113) decreases. For this reason, if the overlapping portion 122 is cylindrical and the thickness of the tip of the overlapping portion 122 (i.e., the end closer to the second surface 112) is smaller than the thickness of the base (i.e., the end closer to the first surface 111), this shear force can be reduced. Therefore, the effect of preventing or suppressing the peeling of the overlapping portion 122 can be enhanced. Note that the overlapping portion 122 does not have to be cylindrical as a whole. For example, the overlapping portion 122 may be provided with a bottomed hole with an open end on the tip side, and the depth of this hole may be smaller than the length of the overlapping portion 122 (the dimension in the direction parallel to the through-hole 113).

[0033] Furthermore, this shear force increases with increasing distance from the neutral point (the point where the overlapping portion 122 and the inner circumferential surface of the through hole 113 do not move relative to each other, assuming that the overlapping portion 122 has contracted (deformed)). Therefore, if this neutral point is located between the tip and base of the overlapping portion 122, this shear force will be greater at the tip of the overlapping portion 122. However, if the thickness of the tip of the overlapping portion 122 is smaller than the thickness of the base, the shear force at the tip can be reduced. Thus, the effect of preventing or suppressing the tip of the overlapping portion 122 from becoming the starting point of delamination can be enhanced.

[0034] Furthermore, as shown in Figure 3A, it is more preferable that the thickness of the overlapping portion 122 gradually (continuously or in steps) decreases from the base end to the tip end. However, the configuration of the overlapping portion 122 in this case is not limited to this configuration. For example, a portion that is thicker than the base end may exist between the base end and the tip end of the overlapping portion 122.

[0035] Furthermore, the multiple through holes 113 provided in a single metal support 11 may have different configurations. In this case, it is sufficient that at least one of the overlapping portions 122 that fits into the through hole 113 has the above-described configuration.

[0036] (Second embodiment) Figure 3B is a cross-sectional view showing the configuration of the overlapping portion 122 according to the second embodiment. The configuration of the through hole 113 is the same as that of the through hole 113 according to the first embodiment. As shown in Figure 3B, the overlapping portion 122 according to the second embodiment has a portion located inside the through hole 113 and a portion located outside the through hole 113 on the side of the second surface 112. For convenience of explanation, the portion located inside the through hole 113 may be referred to as the first overlapping portion 123, and the portion located outside the through hole 113 on the side of the second surface 112 may be referred to as the second overlapping portion 124 to distinguish them. The first overlapping portion 123 of the overlapping portion 122 according to the second embodiment has a hollow cylindrical configuration, similar to the overlapping portion 122 according to the first embodiment shown in Figure 3A. Therefore, the first overlapping portion 123 of the overlapping portion 122 according to the second embodiment can achieve the same effects as the overlapping portion 122 according to the first embodiment.

[0037] Furthermore, the superimposed portion 122 according to the second embodiment includes a second double superimposed portion 124. The second double superimposed portion 124 is the portion that superimposes on the second surface 112 of the metal support 11. The second double superimposed portion 124 is also integrally connected to the first superimposed portion 123. The configuration in which the superimposed portion 122 includes a second double superimposed portion 124 that superimposes on the second surface 112 of the metal support 11 enhances the effect of preventing or suppressing the peeling of the fuel electrode layer 12. That is, when a force is applied to the fuel electrode layer 12 in a direction that peels it away from the metal support 11 (a force that separates it upward), the second double superimposed portion 124 functions as a retainer for the first superimposed portion 123. Therefore, the effect of preventing or suppressing the peeling of the fuel electrode layer 12 from the metal support 11 can be enhanced.

[0038] The second embodiment can achieve the same effects as the first embodiment. Furthermore, by providing the superimposed portion 122 with a cylindrical structure that opens at the tip, it is possible to prevent or suppress the tip of the superimposed portion 122 (first superimposed portion 123) from becoming the starting point of delamination, thereby enhancing the effect of preventing or suppressing delamination of the fuel electrode layer 12 from the metal support 11. In addition, by providing the superimposed portion 122 with a second superimposed portion 124, the effect of preventing or suppressing delamination of the fuel electrode layer 12 from the metal support 11 can be enhanced.

[0039] (modified version) Figure 3C is a cross-sectional view showing the configuration of the superimposed portion 122 according to a modification of the first embodiment, and Figure 3D is a cross-sectional view showing the configuration of the superimposed portion 122 according to a modification of the second embodiment. As shown in Figures 3C and 3D, the superimposed portion 122 may have a solid rod-like configuration instead of a cylindrical one. Even with such a configuration, it is possible to prevent or suppress the peeling of the fuel electrode layer 12 from the metal support 11.

[0040] Next, an example of a method for manufacturing the electrochemical cell 10 will be described.

[0041] A punching process can be applied as a manufacturing method for the metal support 11. That is, by punching a metal plate, which is the material for the metal support 11, a metal support 11 having a predetermined outer shape and dimensions and having a plurality of through holes 113 is manufactured. As mentioned above, the through holes 113 can be formed by changing the conditions of the punching process.

[0042] Then, a layer (film) of the fuel electrode layer 12 material is formed on the first surface 111 of the metal support 11. For example, a paste-like fuel electrode layer 12 material is applied to the first surface 111 of the metal support 11 by screen printing. In this configuration, where the paste-like fuel electrode layer 12 material is applied by screen printing, a portion of the fuel electrode layer 12 material enters each of the multiple through holes 113 formed in the metal support 11. In this case, by changing the printing conditions, etc., it is possible to make the material that enters the through holes 113 (i.e., the material that forms the protrusions) come into contact with the rough parts 114 on the inner circumferential surface of the through holes 113.

[0043] When the material for the fuel electrode layer 12 is applied to the first surface 111 of the metal support 11 by screen printing, the conditions that affect the shape of the formed overlap 122 include the material properties (viscosity, surface tension, fluidity, etc.), squeegee pressure, squeegee speed, screen plate thickness, and the diameter and length of the through-holes 113 (i.e., the thickness of the metal support 11). Specifically, the higher the viscosity of the material, the more difficult it becomes for the material to penetrate into the through-holes 113. The higher the squeegee speed, the more difficult it becomes for the material to penetrate into the through-holes 113. The higher the squeegee pressure, the easier it becomes for the material to penetrate into the through-holes 113. The thicker the screen plate, the more difficult it becomes for the material to penetrate into the through-holes 113. The larger the diameter of the through-holes 113, the easier it becomes for the material to penetrate into the through-holes 113. The longer the length of the through-holes 113, the more difficult it becomes for the material to penetrate into the through-holes 113.

[0044] Therefore, by changing these conditions, a superimposed portion 122 with a desired configuration can be formed. For example, by increasing the squeegee pressure and decreasing the squeegee speed, the superimposed portion 122 shown in Figure 3A can be formed. By further increasing the squeegee pressure compared to the case in which the superimposed portion 122 shown in Figure 3A is formed, the superimposed portion 122 shown in Figure 3C can be formed. Furthermore, by using a material with lower surface tension (higher fluidity) than the case in which the superimposed portion 122 shown in Figure 3A or Figure 3C is formed, and by decreasing the squeegee pressure and squeegee speed, the superimposed portion 122 shown in Figure 3B can be formed. By increasing the squeegee pressure and squeegee speed compared to the case in which the superimposed portion 122 shown in Figure 3B is formed (but lower than the case in which the superimposed portion 122 shown in Figure 3A or Figure 3C is formed), the superimposed portion 122 shown in Figure 3D can be formed.

[0045] Another method can be applied in which, after applying the fuel electrode layer 12 material to the first surface 111 of the metal support 11, firing is not performed for a certain period of time, allowing the material to remain in a paste state so that it enters (flows down) into the through hole 113 by gravity. In other words, the time from applying the fuel electrode layer 12 material to the first surface 111 of the metal support 11 to firing is made longer than in the conventional method. Alternatively, after applying the fuel electrode layer 12 material to the first surface 111 of the metal support 11, the material can be drawn in from the side of the second surface 112 of the metal support 11 (creating negative pressure inside the through hole 113 and the space on the side of the second surface 112 of the metal support 11). With such a method, the superimposed portion 122 can be reliably brought into contact with (superimposed on) the rough portion 114 of the through hole 113 in a short time.

[0046] Furthermore, when forming the overlapping portion 122 shown in Figures 3A and 3B, the amount of material that penetrates into the through-hole 113 is reduced compared to when forming the overlapping portion 122 shown in Figures 3C and 3D (i.e., a solid overlapping portion 122). Alternatively, a material with lower surface tension or higher fluidity is used compared to when forming a solid overlapping portion 122.

[0047] Furthermore, when forming an overlapping section 122 that includes a second overlapping section 124, a method can be applied in which the material for forming the second overlapping section 124 is applied to the second surface 112 of the metal support 11. Specifically, a method can be applied in which the material is applied using a screen configured to allow the material to be applied around the openings on the second surface 112 side of the multiple through holes 113 of the metal support 11, while preventing the material from being applied to other parts (especially the parts that come into contact with the multiple current collectors 212).

[0048] If the fuel electrode layer 12 includes an adhesive layer, the paste-like adhesive layer material is applied to the first surface 111 of the metal support 11 as described above. This allows the adhesive layer to form an overlapping portion 122 having the desired configuration. Then, a layer of material for the portion of the fuel electrode layer 12 other than the adhesive layer (fuel electrode functional layer) is formed on the surface of the adhesive layer material.

[0049] Next, a layer of paste-like electrolyte layer 13 material is formed on the surface of the fuel electrode layer 12 material layer. Then, the fuel electrode layer 12 material layer and the electrolyte layer 13 material layer formed as described above are sintered by heating them to a predetermined temperature. Next, a layer of air electrode layer 14 material is formed on the surface of the electrolyte layer 13. For example, the air electrode layer 14 material, which is a paste-like substance, is applied to the surface of the electrolyte layer 13 by screen printing. Then, the intermediate product with the air electrode layer 14 material layer formed on it is heated to a predetermined temperature to sinter the air electrode layer 14 material and fire the air electrode layer 14. This produces an electrochemical cell 10 (single cell).

[0050] Furthermore, the following method can also be applied as a method for manufacturing the electrochemical cell 10. Similar to the above manufacturing method, a metal support 11 is manufactured using a metal plate as the material. Separately from the metal support 11, a laminated structure is manufactured in which a fuel electrode layer 12, an electrolyte layer 13, and an air electrode layer 14 are laminated. The metal support 11 and the laminated structure are then bonded together with an adhesive or by using an adhesive sheet. Such adhesives or adhesive sheets are made of materials or components that are easily deformable before heating and harden upon heating (functioning as an adhesive).

[0051] Then, an adhesive is applied to the first surface 111 of the metal support 11 or to the surface of the fuel electrode layer 12 of the laminated structure, or an adhesive sheet is attached, and the adhesive layer or adhesive sheet is pressed together with the metal support 11 and the laminate. As a result, a portion of the adhesive layer enters the through hole 113 of the metal support 11. Alternatively, the adhesive sheet deforms, and the deformed portion enters the through hole 113 of the metal support 11. By heating in this state, the electrochemical cell 10 is manufactured. After firing, the adhesive or adhesive sheet forms the adhesive layer of the fuel electrode layer 12.

[0052] <Electrochemical Cell Stack> Next, the electrochemical cell stack 20 to which the electrochemical cell 10 described above is applied will be explained. Figure 4 is a perspective view showing the schematic configuration of the electrochemical cell stack 20. As shown in Figure 4, the electrochemical cell stack 20 has a substantially rectangular parallelepiped shape. The electrochemical cell stack 20 includes an upper end plate 201, a lower end plate 202, and a cell cassette group 203. The upper end plate 201 and the lower end plate 202 are spaced apart from each other in the thickness direction. The upper end plate 201 is located at the top of the rectangular parallelepiped electrochemical cell stack 20. The lower end plate 202 is located at the bottom of the rectangular parallelepiped electrochemical cell stack 20. Both the upper end plate 201 and the lower end plate 202 are substantially quadrilateral flat plate members, arranged so that their thickness direction coincides with the vertical direction, and have substantially the same external shape when viewed in the vertical direction.

[0053] The cell cassette group 203 is positioned between the upper end plate 201 and the lower end plate 202. The cell cassette group 203 has a stacked structure in which multiple substantially flat cell cassettes 204 are stacked. The stacking direction of the multiple cell cassettes 204 constituting the cell cassette group 203 is parallel to the vertical direction and coincides with the thickness direction of the upper end plate 201 and the lower end plate 202.

[0054] Multiple cell cassettes 204 and lower end plates 202 included in the cell cassette group 203 have two gas supply passages Pfi, Pai and two gas discharge passages Pfo, Pao that penetrate in a direction substantially parallel to the stacking direction. The gas supply passage Pfi is formed near one corner of side E1, which is one of the four sides that make up the outer periphery of the substantially quadrilateral electrochemical cell stack 20. The gas discharge passage Pfo is formed near the other corner of side E2, which is parallel to side E1 (the corner located diagonally opposite to one corner of side E1). The gas supply passage Pai is formed near one corner of side E2. The gas discharge passage Pao is formed near the other corner of side E1.

[0055] The gas supply passage Pfi forms the passage through which the fuel electrode gas (a mixture of carbon dioxide and water vapor) supplied to each fuel electrode chamber Sf (described later) of the electrochemical cell stack 20 passes. The gas supply passage Pai forms the passage through which the air electrode gas (air) supplied to each air electrode chamber Sa (described later) of the electrochemical cell stack 20 passes. The gas discharge passage Pfo forms the passage through which carbon monoxide, hydrogen, and unreacted water vapor discharged from each fuel electrode chamber Sf of the electrochemical cell stack 20 passes. The gas discharge passage Pao forms the passage through which oxygen and air discharged from each air electrode chamber Sa of the electrochemical cell stack 20 passes.

[0056] Figures 5A and 5B are schematic cross-sectional views of the electrochemical cell stack 20 cut by planes parallel to the vertical direction. Also, Figures 5A and 5B are views from directions perpendicular to each other. However, Figures 5A and 5B are not views cut by a specific plane. As shown in Figures 5A and 5B, the cell cassette 204 comprises a frame section 220, a reaction section 210, and a separator section 230.

[0057] The frame section 220 includes a fuel electrode side frame 221 and an air electrode side frame 222. The fuel electrode side frame 221 is a substantially quadrilateral plate-shaped metal (e.g., stainless steel) member, with a substantially quadrilateral opening formed in the central portion when viewed in the vertical direction. The air electrode side frame 222 is positioned above the fuel electrode side frame 221. The air electrode side frame 222 is a substantially quadrilateral plate-shaped member with electrical insulating properties, and may be formed from, for example, a mica sheet. The air electrode side frame 222 also has a substantially quadrilateral opening formed in the central portion when viewed in the vertical direction, similar to the fuel electrode side frame 221. The shape of the frame section 220 when viewed in the vertical direction matches the shape of the upper end plate 201 and the lower end plate 202.

[0058] The reaction section 210 is disposed inside an opening formed in the central part of the frame section 220. In other words, the frame section 220 is disposed around the outer circumference of the reaction section 210 so as to surround it. A predetermined gap is formed between the frame section 220 and the reaction section 210. The reaction section 210 includes the electrochemical cell 10, the interconnector 213, and a plurality of current collectors 212.

[0059] The interconnector 213 is a metal (for example, stainless steel) component and has a roughly quadrilateral, flat main body 214 and a projection 215 that protrudes downward from the lower surface of the main body 214. The main body 214 is positioned so that its outer circumference overlaps the upper surface of the air electrode side frame 222 of the frame 220. The main body 214 of the interconnector 213 closes the opening of the frame 220 from above. The projection 215 is formed by a plurality of vertical wall-like protrusions that project downward. The plurality of protrusions are spaced apart at predetermined intervals and are roughly parallel to each other. Between the protrusions of the projection 215 of the interconnector 213, there is a space (which can also be called a gap) that extends in a direction parallel to the longitudinal direction of the protrusions and through which gas can pass. The interconnector 213 is positioned above the electrochemical cell 10. Furthermore, the protrusions of the projection 215 of the interconnector 213 are in contact with the air electrode layer 14 of the electrochemical cell 10.

[0060] Each of the multiple current collectors 212 comprises a substantially rod-shaped insulator and a conductor provided to cover the outer surface of the insulator. The multiple current collectors 212 are arranged to be substantially parallel to each other at a predetermined distance apart. As a result, a space is formed between adjacent current collectors 212 that allows gas to pass through (see Figure 5B). The multiple current collectors 212 are arranged such that their longitudinal direction is perpendicular to the extending direction of the protrusion 215 of the interconnector 213 when viewed from above. The multiple current collectors 212 are located on the underside of the electrochemical cell 10. The upper surfaces of the multiple current collectors 212 are in contact with the second surface 112 of the metal support 11 of the electrochemical cell 10, and the lower surfaces of the multiple current collectors 212 are in contact with the upper surface of the main body 214 of the interconnector 213 of another cell cassette 204 adjacent to the underside of the cell cassette 204 containing these current collectors 212. Furthermore, the multiple current collectors 212 are positioned so as not to block the first through-hole 113a and the second through-hole 113b provided in the metal support 11 of the electrochemical cell 10 (see Figure 5B). In addition, in a configuration in which the superimposed portion 122 of the fuel electrode layer 12 has a second double superimposed portion 124, the multiple current collectors 212 are positioned so as not to contact the second double superimposed portion 124 (in other words, not to superimpose in the vertical direction).

[0061] The separator section 230 is positioned to fill the gap formed between the frame section 220 and the reaction section 210. The separator section 230 is a roughly quadrilateral plate-shaped metal (e.g., stainless steel) member, with a roughly quadrilateral opening formed in its central portion. The periphery (i.e., inner periphery) of the opening of the separator section 230 is brazed to the upper surface of the outer periphery of the electrolyte layer 13 of the electrochemical cell 10 with a brazing material (e.g., Ag brazing) not shown. On the other hand, the outer periphery portion of the separator section 230 is positioned on the upper surface of the fuel electrode side frame 221 and is joined to the fuel electrode side frame 221 by, for example, welding.

[0062] A cell cassette group 203 is formed by stacking multiple cell cassettes 204 having the above configuration. When the cell cassettes 204 are stacked in this manner, each cell cassette 204 is stacked in the thickness direction of the electrochemical cell 10. That is, the electrochemical cell stack 20 has a stacked structure in which multiple electrochemical cells 10 are stacked. In addition, the frame portions 220 of each cell cassette 204 are stacked together, and the reaction portions 210 of each cell cassette 204 are stacked together. Furthermore, the separator portion 230 and the main body portion 214 of the interconnector 213 are arranged alternately with a predetermined gap in the stacking direction (or they can be spaced apart in the stacking direction).

[0063] In addition, a current collector plate 205 is positioned below the lowest cell cassette 204. The current collector plate 205 is a flat, conductive material. The upper surface of the current collector plate 205 is in contact with the current collector 212 of the lowest cell cassette 204. The outer periphery of the current collector plate 205 is positioned between the frame portion 220 and the lower end plate 202 of the lowest cell cassette 204.

[0064] Then, the space on the inner circumference side of the frame portion 220 is partitioned by the separator portion 230 and the main body portion 214 of the interconnector 213. As a result, multiple fuel electrode chambers Sf and air electrode chambers Sa are formed inside the cell cassette group 203, with gas flow being blocked from each other.

[0065] The fuel electrode chamber Sf is a space that allows the flow of fuel electrode gas supplied from outside the electrochemical cell stack 20 and gases generated in the fuel electrode layer 12 of the electrochemical cell 10. In this embodiment, the fuel electrode gas is a mixture of water vapor and carbon dioxide, and the gases generated in the fuel electrode layer 12 are hydrogen and carbon monoxide. The fuel electrode chamber Sf is formed by a fuel electrode side frame 221, a separator section 230 joined to the upper side of the fuel electrode side frame 221, an electrochemical cell 10 connected to the separator section 230, and the main body 214 of an interconnector 213 joined to the fuel electrode side frame 221 (however, this interconnector 213 is an interconnector 213 included in another cell cassette 204 adjacent to the lower side). Therefore, the fuel electrode chamber Sf contains the current collector 212 and the fuel electrode layer 12, and the space between the current collectors 212 is included in the fuel electrode chamber Sf. Furthermore, a portion of the fuel electrode layer 12 is exposed inside the fuel electrode chamber Sf.

[0066] The air electrode chamber Sa is a space that allows the flow of air electrode gas supplied from outside the electrochemical cell stack 20 and the gas generated in the air electrode layer 14. In this embodiment, the air electrode gas is air, and the gas generated in the air electrode layer 14 is oxygen. The air electrode chamber Sa is formed by the air electrode side frame 222, the interconnector 213 connected to the upper side of the air electrode side frame 222, the separator section 230 connected to the lower side of the air electrode side frame 222, and the electrochemical cell 10 connected to the separator section 230. Therefore, the air electrode chamber Sa encloses the protrusions 215 of the interconnector 213 and the air electrode layer 14 of the electrochemical cell 10, and the space between the protrusions 215 is included in the air electrode chamber Sa. In addition, a part of the air electrode layer 14 is exposed inside the air electrode chamber Sa. In other words, a part of the inner circumferential surface of the air electrode chamber Sa is formed by the air electrode layer 14.

[0067] The gas supply passage Pfi and the gas discharge passage Pfo are formed to penetrate the lower end plate 202, the current collector plate 205, and the frame portion 220 of each cell cassette 204 constituting the cell cassette group 203 in a direction substantially parallel to the stacking direction. The gas supply passage Pfi communicates with the fuel electrode chamber Sf through a lateral hole formed in the fuel electrode side frame 221 of each cell cassette 204. Similarly, the gas discharge passage Pfo communicates with the fuel electrode chamber Sf through a lateral hole formed in the fuel electrode side frame 221 of each cell cassette 204.

[0068] The gas supply passage Pai and the gas discharge passage Pao are also formed to penetrate the lower end plate 202, the current collector plate 205, and the frame portion 220 of each cell cassette 204 that constitute the cell cassette group 203 in the stacking direction. The gas supply passage Pai communicates with the air electrode chamber Sa through a lateral hole formed in the air electrode side frame 222 of each cell cassette 204. Similarly, the gas discharge passage Pao also communicates with the air electrode chamber Sa through a lateral hole formed in the air electrode side frame 222 of each cell cassette 204.

[0069] Next, the operation of this electrochemical cell stack 20 will be described. When hydrogen and oxygen are produced by steam electrolysis in the electrochemical cell stack 20, an electrolytic current is passed through the electrochemical cell stack 20. In this case, the negative electrode of the power supply is connected to the current collector plate 205, and the positive electrode of the power supply is connected to the interconnector 213 of the uppermost cell cassette 204. High-temperature steam is supplied as fuel electrode gas to the gas supply passage Pfi. The fuel electrode gas supplied to the gas supply passage Pfi flows into the fuel electrode chamber Sf of each cell cassette 204. High-temperature air is supplied as air electrode gas to the gas supply passage Pai. The air electrode gas supplied to the gas supply passage Pai flows into the air electrode chamber Sa of each cell cassette 204. The reason for supplying high-temperature air to the air electrode chamber Sa is to control the temperature of the electrochemical cell stack 20 and to prevent short circuits between the separator section 230 and the interconnector 213.

[0070] The water vapor contained in the fuel electrode gas flowing into each fuel electrode chamber Sf reacts with electrons supplied via the interconnector 213 and current collector 212 in the fuel electrode layer 12 to decompose into hydrogen and oxide ions. In this way, an electrolytic reaction of water vapor (water) occurs in the fuel electrode layer 12. The generated hydrogen is discharged from the electrochemical cell stack 20 through the gas discharge passage Pfo. At this time, unreacted water vapor is discharged from the electrochemical cell stack 20 through the gas discharge passage Pfo along with the hydrogen. Meanwhile, the oxide ions move through the electrolyte layer 13 to the air electrode layer 14 in the air electrode chamber Sa, where they release electrons in the functional layer of the air electrode layer 14 to become oxygen. The oxygen flows through the air electrode chamber Sa together with the air electrode gas, and is discharged from the electrochemical cell stack 20 through the gas discharge passage Pao.

[0071] <Hot Modules and Electrolytic Reactors> Next, the hot module 31 to which the electrochemical cell stack 20 is applied and the electrolytic reactor 30 equipped with this hot module 31 will be described. Figure 6 is a schematic block diagram showing an example of the configuration of the main parts of the electrolytic reactor 30 according to this embodiment. The electrolytic reactor 30 according to this embodiment is a device that can produce hydrogen and oxygen by electrolyzing water vapor. As shown in Figure 6, the electrolytic reactor 30 includes a hot module 31 and a condenser 36.

[0072] The hot module 31 is constructed by covering the main components of the electrolytic reaction apparatus 30 that become hot with an insulating member 35, and is a device in which the main components are concentrated inside the insulating member 35 so that the high temperature state of the main components is maintained. This hot module 31 comprises the electrochemical cell stack 20, vaporizer 32, heat exchanger 33, heater 34, and insulating member 35.

[0073] As shown in Figure 6, water (H2O) is supplied to the vaporizer 32. The vaporizer 32 is configured to heat the supplied water to a temperature of 100°C or higher by a heat source (not shown in the figure). As the water evaporates within the vaporizer 32, steam is generated. The steam generated in the vaporizer 32 is supplied to the heat exchanger 33.

[0074] In addition to the aforementioned mixture, air is supplied to the heat exchanger 33. Furthermore, the heat exchanger 33 is supplied with a mixture of high-temperature hydrogen (H2) and water vapor, and high-temperature oxygen (O2) and air (oxygen-rich air), which are generated in the fuel polar layer 12 of the electrochemical cell stack 20. Then, in the heat exchanger 33, these mixtures of high-temperature hydrogen and carbon monoxide and the mixture of oxygen and air exchange heat with the water vapor and air, causing the water vapor and air to be heated (heated up).

[0075] The steam and air heated in the heat exchanger 33 are further heated by the heater 34 to the operating temperature of the electrochemical cell stack 20 (i.e., the temperature required for the reaction to occur in the electrochemical cell stack 20). Subsequently, the steam is supplied to each fuel electrode chamber Sf of the electrochemical cell stack 20, and the air is supplied to each air electrode chamber Sa of the electrochemical cell stack 20. The heat exchanger 33 and heater 34 are heating devices that raise the gas (steam and air) supplied to the electrochemical cell stack 20 to the operating temperature of the electrochemical cell stack 20.

[0076] A predetermined current is passed through the electrochemical cell stack 20. This current is sometimes referred to as the electrolytic current. This causes an electrolytic reaction of water vapor to occur in the electrochemical cell stack 20, producing hydrogen and oxygen.

[0077] The hydrogen generated in the fuel polar layer 12 of the electrochemical cell stack 20 is supplied to the heat exchanger 33 along with unreacted water vapor. The hydrogen and unreacted water vapor are then used to heat the water vapor and air supplied from the vaporizer 32 to the heat exchanger 33, and then introduced to the condenser 36. In the condenser 36, the unreacted water vapor condenses, and the condensed water produced in the condenser 36 is supplied to the vaporizer 32. Meanwhile, the hydrogen separated by the condensation of water vapor in the condenser 36 is recovered. The oxygen generated in the electrochemical cell stack 20 is supplied to the heat exchanger 33 along with air, used to heat the water vapor and air, and then supplied to the vaporizer 32, used to heat the water supplied to the vaporizer 32. The oxygen discharged from the vaporizer 32 is either recovered or released into the atmosphere along with the air.

[0078] The electrochemical cell stack 20, vaporizer 32, heat exchanger 33, and heater 34 are arranged inside the insulating member 35. This suppresses heat dissipation from the electrochemical cell stack 20, vaporizer 32, heat exchanger 33, and heater 34 to the outside of the hot module 31. The insulating member 35 may be made of heat-resistant fibers such as ceramic wool, refractory ceramic fiber (RCF), biosoluble fiber (AES), and / or heat-resistant containers molded from these heat-resistant fibers. The heat-resistant fibers are arranged to fill the gaps between the electrochemical cell stack 20, vaporizer 32, heat exchanger 33, and heater 34.

[0079] Although embodiments of this disclosure have been described above, the technology relating to this disclosure should not be limited to the embodiments described above.

[0080] In the above embodiment, an example was shown in which the electrochemical cell 10 is a component (element) capable of producing hydrogen by electrolyzing water vapor (water), but the electrochemical cell 10 is not limited to such a configuration. The electrochemical cell 10 may also be a component (element) capable of generating electricity by reacting hydrogen and oxygen. In this case, hydrogen is applied as the fuel electrode gas, and an oxygen-containing gas (specifically air) is applied as the air electrode gas. An electrolytic reactor 30 equipped with an electrochemical cell stack 20 to which such an electrochemical cell 10 is applied is a power generation device that can generate electricity using the reaction between hydrogen and oxygen.

[0081] Furthermore, this disclosure may include the following aspects:

[0082] [1] The device comprises an electrolyte layer, an air electrode layer laminated on one surface of the electrolyte layer, a fuel electrode layer laminated on the other surface of the electrolyte layer, and a plate-shaped metal support laminated on the surface of the fuel electrode layer opposite to the side facing the electrolyte layer. The metal support has a plurality of through holes that connect a first surface, which is the surface facing the fuel electrode layer, and a second surface, which is the surface opposite to the first surface. The inner circumferential surface of at least one of the through holes comprises a rough portion and a smooth portion, each having different arithmetic mean roughness in the through-direction of at least one of the through holes. The smooth portion is provided between the rough portion and the first surface. The fuel electrode layer comprises an overlapping portion having a portion that covers the rough portion of at least one of the through holes. Electrochemical cell.

[0083] [2] The electrochemical cell described in [1] above, The thickness of the overlapping portion at the end on the first surface side, in a direction approximately perpendicular to the penetration direction of the through hole, is greater than the thickness at the end on the second surface side. Electrochemical cell.

[0084] [3] An electrochemical cell as described in [1] or [2] above, The opening area of ​​at least one of the through holes at the end of the rough portion closest to the second surface is greater than the opening area at the end closest to the first surface. Electrochemical cell.

[0085] [4] An electrochemical cell according to any one of the above [1] to [3], The arithmetic mean roughness of at least one of the through holes in the smooth portion in the direction of penetration is greater than or equal to the arithmetic mean roughness of the first surface. Electrochemical cell.

[0086] [5] A plurality of electrochemical cells as described in any of [1] to [4] above, The electrochemical cells are arranged in a stacked structure, Electrochemical cell stack.

[0087] [6] The electrochemical cell stack described in [5] above, A heating device for heating the gas supplied to the electrochemical cell stack, The electrochemical cell stack and the heating device are insulated from a heat insulating member located inside them. A hot module equipped with this feature.

[0088] [7] An electrolytic reaction apparatus comprising the hot module described in [6] above. [Explanation of symbols]

[0089] 10...Electrochemical cell, 11...Metal support, 12...Fuel electrode layer, 121...Plate-shaped part, 122...Overlay part, 123...First overlay part, 124...Second double overlay part, 13...Electrolyte layer, 14...Air electrode layer, 20...Electrochemical cell stack, 30...Electrolytic reaction apparatus, 31...Hot module, 32...Vaporizer, 33...Heat exchanger (heating device), 34...Heater (heating device), 35...Insulation member, 111...First surface, 112...Second surface, 113...Through hole, 113b...Second through hole, 114...Rough part, 115...Smooth part, 203...Cell cassette group, 204...Cell cassette

Claims

1. The device comprises an electrolyte layer, an air electrode layer laminated on one surface of the electrolyte layer, a fuel electrode layer laminated on the other surface of the electrolyte layer, and a plate-shaped metal support laminated on the surface of the fuel electrode layer opposite to the side facing the electrolyte layer. The metal support has a plurality of through holes that connect a first surface, which is the surface facing the fuel electrode layer, and a second surface, which is the surface opposite to the first surface. The inner circumferential surface of at least one of the through holes comprises a rough portion and a smooth portion provided between the rough portion and the first surface, the arithmetic mean roughness in the through direction of at least one of the through holes being smaller than that of the rough portion. The opening area of ​​the end of the rough portion near the second surface in at least one of the through holes provided in the metal support is larger than the opening area of ​​the end of the rough portion near the first surface. The fuel electrode layer comprises an overlapping portion having a portion that covers the rough part of at least one of the through holes. Electrochemical cell.

2. An electrochemical cell according to claim 1, The thickness of the overlapping portion at the end on the first surface side, in a direction approximately perpendicular to the penetration direction of the through hole, is greater than the thickness at the end on the second surface side. Electrochemical cell.

3. An electrochemical cell according to claim 1, The arithmetic mean roughness of at least one of the through holes in the smooth portion in the direction of penetration is greater than or equal to the arithmetic mean roughness of the first surface. Electrochemical cell.

4. A plurality of electrochemical cells according to any one of claims 1 to 3, The electrochemical cells are arranged in a stacked structure, Electrochemical cell stack.

5. The electrochemical cell stack according to Claim 4, A heating device for heating the gas supplied to the electrochemical cell stack, The electrochemical cell stack and the heating device are insulated from a heat insulating member located inside them. A hot module equipped with this feature.

6. An electrolytic reaction apparatus comprising the hot module described in Claim 5.

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