Patent ID: 12212023

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of a cell stack device, a module, a module housing device, and a metal member that are disclosed in the present application will be described with reference to the accompanying drawings. The disclosure is not limited by the following embodiments.

Note, further, that the drawings are schematic and that the dimensional relationships between elements, the proportions thereof, and the like may differ from the actual ones. There may be differences between the drawings in the dimensional relationships, proportions, and the like.

In recent years, various fuel cell stack devices each including a plurality of fuel cells arrayed therein have been proposed as next-generation energy sources, the plurality of fuel cells being each a type of cell capable of generating electrical power using a fuel gas such as a hydrogen-containing gas and an oxygen-containing gas such as air.

In such a fuel cell stack device, an end current collector made of a metal material is located, for example, in an end portion of a cell stack in an array direction of the plurality of fuel cells.

However, the aforementioned end current collector is exposed to both an oxidizing atmosphere such as air and a reducing atmosphere such as a hydrogen-containing gas at different sites, and a surface thereof may be durable against one of the atmospheres while less durable against the other of the atmospheres.

Thus, a technique to overcome the aforementioned problem and improve the durability of the fuel cell stack device awaits realization.

Configuration of Cell

First, an example of a solid oxide fuel cell will be described as a cell constituting a cell stack device according to an embodiment with reference toFIGS.1A to1C.

FIG.1Ais a horizontal cross-sectional view illustrating an example of a cell1according to an embodiment.FIG.1Bis a side view illustrating an example of the cell1according to the embodiment when viewed from an air electrode5side.FIG.1Cis a side view illustrating an example of the cell1according to the embodiment when viewed from an interconnector6side. Note thatFIGS.1A to1Ceach illustrate an enlarged part of a configuration of the cell1.

In the example illustrated inFIGS.1A to1C, the cell1has a hollow flat plate shape or an elongated plate shape. As illustrated inFIG.1B, the overall shape of the cell1when viewed from the side is, for example, a rectangle having a side length of from 5 cm to 50 cm in a length direction L and a length of from 1 cm to 10 cm in a width direction W orthogonal to the length direction L. The total length (thickness direction T) of the cell1is from 1 mm to 5 mm.

As illustrated inFIG.1A, the cell1includes a support substrate2that is conductive, an element portion, and an interconnector6. The support substrate2has a columnar shape having a pair of a first flat surface n1and a second flat surface n2that face each other, and a pair of arc-shaped side surfaces m that connect the first flat surface n1and the second flat surface n2.

The element portion is located on the first flat surface n1of the support substrate2. The element portion includes a fuel electrode3, a solid electrolyte layer4, and an air electrode5. In the example illustrated inFIG.1A, the interconnector6is located on the second flat surface n2of the cell1.

As illustrated inFIG.1B, the air electrode5does not extend to a lower end of the cell1. At the lower end portion of the cell1, only the solid electrolyte layer4is exposed on a surface of the first flat surface n1. As illustrated inFIG.1C, the interconnector6may extend to the lower end of the cell1. At the lower end portion of the cell1, the interconnector6and the solid electrolyte layer4are exposed on the surface. Note that, as illustrated inFIG.1A, the solid electrolyte layer4is exposed on surfaces of the pair of arc-shaped side surfaces m of the cell1. The interconnector6may or may not extend to the lower end of the cell1.

Hereinafter, respective constituent members constituting the cell1will be described.

The support substrate2is provided therein with gas flow paths2athrough which a gas flows.FIG.1Aillustrates an example in which six gas flow paths2aextending along the length direction are provided. The support substrate2has gas permeability and allows a fuel gas to permeate to the fuel electrode3. The support substrate2illustrated inFIG.1Ahas conductivity. The support substrate2collects electricity generated in the element portion via the interconnector6.

The material of the support substrate2contains, for example, an iron group metal component and an inorganic oxide. The iron group metal component in the support substrate2may be, for example, Ni and/or NiO. The inorganic oxide in the support substrate2may be a specific rare earth element oxide.

As the material of the fuel electrode3, a generally known material may be used. As the material for the fuel electrode3, a porous conductive ceramic, for example, a ceramic containing a solid solution of a calcium oxide, a magnesium oxide, or a rare earth element oxide in ZrO2and Ni and/or NiO may be used. As the rare earth element oxide, Y2O3or the like, for example, is used.

Hereinafter, the solid solution of a calcium oxide, a magnesium oxide, or a rare earth element oxide in ZrO2and Ni and/or NiO is referred to as stabilized zirconia. In the present disclosure, stabilized zirconia also includes partially stabilized zirconia.

The solid electrolyte layer4is an electrolyte and bridges ions between the fuel electrode3and the air electrode5. The solid electrolyte layer4also has a gas blocking property and suppresses leakage of the fuel gas and the oxygen-containing gas.

The material of the solid electrolyte layer4is, for example, a solid solution of from 3 mol % to 15 mol % of a rare earth element oxide in ZrO2. As the rare earth element oxide, Y2O3or the like, for example, is used. Note that another material may be used as the material of the solid electrolyte layer4, provided that the former has the aforementioned characteristics.

The material of the air electrode5is not particularly limited, provided that the material is generally used for an air electrode. The material of the air electrode5may be, for example, a conductive ceramic such as an ABO3type perovskite oxide.

The material of the air electrode5may be, for example, a composite oxide in which Sr and La coexist in an A site. Examples of such a composite oxide include LaxSr1-xCoyFe1-yO3, LaxSr1-xMnO3, LaxSr1-xFeO3, and LaxSr1-xCoO3. Here, x is 0<x<1 and y is 0<y<1.

The air electrode5has gas permeability. The open porosity of the air electrode5may be 20% or more, particularly in the range of from 30% to 50%.

As the material of the interconnector6, a lanthanum chromite-based perovskite oxide (LaCrO3-based oxide), a lanthanum strontium titanium-based perovskite oxide (LaSrTiO3-based oxide), or the like may be used. These materials have conductivity, and are neither reduced nor oxidized even when in contact with a fuel gas such as a hydrogen-containing gas and an oxygen-containing gas such as air.

The interconnector6is dense and suppresses leakage of the fuel gas flowing through the gas flow paths2alocated inside the support substrate2and the oxygen-containing gas flowing outside the support substrate2. The interconnector6may have a relative density of 93% or more, particularly 95% or more.

Configuration of Cell Stack Device

Next, a cell stack device10according to the present embodiment using the cell1described above will be described with reference toFIGS.2A to2C.FIG.2Ais a perspective view illustrating an example of the cell stack device10according to the embodiment.FIG.2Bis a cross-sectional view taken along line X-X illustrated inFIG.2A.FIG.2Cis a top view illustrating an example of the cell stack device10according to the embodiment.

As illustrated inFIG.2A, the cell stack device10is provided with a cell stack11including a plurality of the cells1arrayed (stacked) in the thickness direction T (seeFIG.1A) of the cells1, and a fixing member12.

The fixing member12includes a fixing material13and a support member14. The support member14supports the cells1. The fixing material13fixes the cells1to the support member14. Furthermore, the support member14includes a support body15and a gas tank16. The support body15and the gas tank16, which constitute the support member14, are made of metal and have conductivity.

As illustrated inFIG.2B, the support body15includes an insertion hole15ainto which the lower end portions of the plurality of cells1are inserted. The lower end portions of the plurality of cells1and an inner wall of the insertion hole15aare bonded by the fixing material13.

The gas tank16includes an opening portion for supplying a reaction gas to the plurality of cells1via the insertion hole15aand a recessed groove16alocated in a periphery of the opening portion. An outer peripheral end portion of the support body15is bonded to the gas tank16by a bonding material21filled in the recessed groove16aof the gas tank16.

In the example illustrated inFIG.2A, the fuel gas is stored in an internal space22(seeFIG.2B) formed by the support body15and the gas tank16, which constitute the support member14. The gas tank16includes a gas circulation pipe20connected thereto. The fuel gas is supplied to the gas tank16through the gas circulation pipe20, and is supplied from the gas tank16to the gas flow paths2a(seeFIG.1A) inside the cell1. The fuel gas supplied to the gas tank16is generated by a reformer82(seeFIG.13) to be described below.

The hydrogen-rich fuel gas may be produced, for example, by steam reforming a raw material. The fuel gas produced by steam reforming includes steam.

The example illustrated inFIG.2Aincludes two rows of the cell stacks11, two of the support bodies15, and the gas tank16. Each of the two rows of the cell stacks11includes the plurality of cells1. Each of the cell stacks11is fixed to a corresponding one of the support bodies15. The gas tank16includes two through holes on an upper surface thereof. Each of the support bodies15is disposed in a corresponding one of the through holes. The internal space22is formed by one gas tank16and two support bodies15.

The insertion hole15ahas, for example, an oval shape in a top surface view. The length of the insertion hole15a, for example, in the array direction of the cells1, that is, the thickness direction T thereof, is larger than the distance between two end current collectors17located at two ends of the cell stack11. The width of the insertion hole15ais, for example, larger than the length of the cell1in a width direction W (seeFIG.1A).

As illustrated inFIG.2B, the fixing material13is filled and solidified in a bonding portion between the inner wall of the insertion hole15aand the lower end portions of the cells1. Consequently, the inner wall of the insertion hole15aand the lower end portions of the plurality of cells1are bonded and fixed, and the lower end portions of the cells1are bonded and fixed to each other. Each of the cells1includes, at the lower end portions thereof, the gas flow paths2athat communicate with the internal space22of the support member14.

The fixing material13and the bonding material21can each be a material having low conductivity. As a specific material of the fixing material13and the bonding material21, an amorphous glass or the like may be used, or particularly, a crystallized glass or the like may be used.

As the crystallized glass, for example, any of SiO2—CaO-based, MgO—B2O3-based, La2O3—B2O3—MgO-based, La2O3—B2O3—ZnO-based, and SiO2—CaO—ZnO-based materials may be used, or, particularly, a SiO2—MgO-based material may be used.

Also, as illustrated inFIG.2B, an electrically conductive member18that electrically connect the cells1in series is disposed between the cells1adjacent to each other (more particularly between the fuel electrode3of one of the cells1and the air electrode5of the other of the cells1). More specifically, “between the cells1adjacent to each other” corresponds to “between the fuel electrode3of one of the cells1adjacent to each other and the air electrode5of the other thereof”.

As illustrated inFIG.2B, the end current collectors17are connected to the cells1on outermost sides in the array direction of the plurality of cells1. The end current collectors17are each connected to an electrically conductive portion19protruding outward from the cell stack11. The electrically conductive portion19has a function of collecting electricity generated by the cells1and sending the electricity thus collected to the outside. Note that FIG.2A does not illustrate the end current collectors17, the electrically conductive member18, or the electrically conductive portion19.

As illustrated inFIG.2C, the cell stack device10includes two cell stacks, which are cell stacks11A and11B, that are connected in series and function as one battery. Thus, the electrically conductive portion19of the cell stack device10is divided into a positive electrode terminal19A, a negative electrode terminal19B, and a connection terminal19C.

The positive electrode terminal19A functions as a positive electrode when power generated by the cell stack11is output to the outside, and is electrically connected to the end current collector17on a positive electrode side in the cell stack11A. The negative electrode terminal19B functions as a negative electrode when power generated by the cell stack11is output to the outside, and is electrically connected to the end current collector17on a negative electrode side in the cell stack11B.

The connection terminal19C electrically connects the end current collector17on a negative electrode side in the cell stack11A and the end current collector17on a positive electrode side in the cell stack11B.

Details of End Current Collector

Next, details of the end current collector17according to an embodiment will be described with reference toFIG.3.FIG.3is a cross-sectional view illustrating the end current collector17according to an embodiment. The end current collector17is an example of a metal member.

As illustrated inFIG.3, one end (lower end portion in the drawing) of the end current collector17is inserted into the insertion hole15aalong with the plurality of cells1(seeFIG.2B), and is fixed to the fixing material13in the insertion hole15a. That is, a side surface of the one end (lower end portion) of the end current collector17contacts the fixing material13.

Further, a surface of a portion (for example, a bottom surface) in the one end (lower end portion) of the end current collector17is exposed to the internal space22formed by the support member14(seeFIG.2B). The internal space22is a space that the fuel electrode3of the cell1contacts through the support substrate2as described above, and is filled with a fuel gas such as a hydrogen-containing gas. That is, the internal space22is a reducing atmosphere.

On the other hand, a surface of the end current collector17other than that of the one end (lower end portion) is exposed to an external space23. The external space23is a space that the air electrode5of the cell1is exposed to, and is filled with oxygen-containing gas such as air. That is, the external space23is an oxidizing atmosphere.

As illustrated inFIG.3, the end current collector17used in such an environment is preferably covered with a covering material17bon the surface (first surface) exposed to the oxidizing atmosphere (external space23). The material of the covering material17bis, for example, an electrically conductive oxide containing manganese (Mn) (e. g., ZnMnCoO4). The covering material17bis formed on a surface of a base material17aby, for example, electrodeposition coating or the like. Note that, in the embodiment, the material of the base material17aof the end current collector17is, for example, stainless steel.

A surface of the end current collector17can be covered with the covering material17bto suppress separation of chromium (Cr) contained in the base material17ainto the oxidizing atmosphere (external space23) during high temperature operation, thus enhancing the durability of the end current collector17.

On the other hand, when the covering material17bis exposed to a reducing atmosphere (for example, the internal space22), the manganese, which is the constituent element of the covering material17b, is reduced and separated from the covering material17b, and the durability of the end current collector17may decrease.

Thus, in the embodiment, a surface (the bottom surface in the drawing) exposed to the reducing atmosphere (internal space22) in the end current collector17is covered with a film different from the covering material17b. For example, in the embodiment, the surface exposed to the reducing atmosphere is covered with a natural oxide film17a1of the base material17a.

The material of the natural oxide film17a1is, for example, chromium oxide (Cr2O3). The constituent element of the natural oxide film17a1seldom has a reduction reaction even in a reducing atmosphere.

Accordingly, the separation of the constituent element from the surface (second surface) exposed to the reducing atmosphere (internal space22) can be suppressed. Thus, the embodiment can enhance the durability of the end current collector17and enhance the durability of the cell stack device10.

The natural oxide film17a1can be formed, for example, by forming the covering material17ball over the surface of the base material17a, then etching a predetermined location (here, a bottom surface) with sulfuric acid or the like, and treating an exposed surface of the base material17aat a high temperature in an oxidizing atmosphere.

The embodiment allows for low-cost manufacturing of the end current collector17by covering the surface exposed to the reducing atmosphere with the natural oxide film17a1, which can be easily formed.

Various Variations

Next, the configuration of the end current collector17according to various variations of the embodiment will be described with reference toFIGS.4to12.FIG.4is a cross-sectional view illustrating the end current collector17according to a modified example 1 of the embodiment.

The film covering the surface exposed to the reducing atmosphere is not limited to the natural oxide film17a1, although the aforementioned embodiment illustrates an example in which the surface exposed to the reducing atmosphere (internal space22) in the end current collector17is covered with the natural oxide film17a1.

For example, as illustrated inFIG.4, the surface exposed to the reducing atmosphere (internal space22) may be covered by a reduction preventing film17c. The constituent element of the material of the reduction preventing film17cseldom has a reduction reaction in a reducing atmosphere, and examples thereof include forsterite and alumina (Al2O3).

The bottom surface can be covered with the reduction preventing film17cto suppress the separation of the constituent element thereof from the surface exposed to the reducing atmosphere (internal space22). Thus, the modified example 1 can enhance the durability of the end current collector17, and can thereby enhance the durability of the cell stack device10.

Further, the modified example 1, in which a material other than stainless steel can be used as the base material17aof the end current collector17, can realize high performance (for example, an improvement in electrical conductivity) of the end current collector17.

FIG.5is a cross-sectional view illustrating the end current collector17according to a modified example 2 of the embodiment. As illustrated inFIG.5, in the end current collector17according to the modified example 2, not only the surface exposed to the reducing atmosphere (internal space22) but also the surface (third surface) contacting the fixing material13are covered with a film different from the covering material17b.

For example, in the example ofFIG.5, the surface exposed to the reducing atmosphere and the surface contacting the fixing material13are covered with the natural oxide film17a1of the base material17a.

By covering the surface contacting the fixing material13with a film different from the covering material17b, generation of cracks and the like in the covering material17bdue to manganese, which is the constituent element of the covering material17b, being diffused during high temperature operation into the fixing material13, which is a glass material, can be suppressed.

Thus, the modified example 2 can further enhance the durability of the end current collector17and can thereby further enhance the durability of the cell stack device10.

Further, in the modified example 2, the surface exposed to the reducing atmosphere and the surface contacting the fixing material13can be covered with the natural oxide film17a1that can be easily formed, and thus the end current collector17can be manufactured at low cost.

FIG.6is a cross-sectional view illustrating the end current collector17according to a modified example 3 of the embodiment. WhileFIG.5described above illustrates an example in which the surface exposed to the reducing atmosphere and the surface contacting the fixing material13are covered with the natural oxide film17a1, the film covering these surfaces is not limited to the natural oxide film17a1.

For example, as illustrated inFIG.6, the surface exposed to the reducing atmosphere and the surface contacting the fixing material13may be covered by the reduction preventing film17c. This can suppress the separation of the constituent elements from the surface exposed to the reducing atmosphere and the surface contacting the fixing material13.

Thus, the modified example 3 can further enhance the durability of the end current collector17, and can thereby further enhance the durability of the cell stack device10.

Note thatFIG.5andFIG.6respectively illustrate an example in which the natural oxide film17a1or the reduction preventing film17cis located all over the surface contacting the fixing material13of the end current collector17. On the other hand, in the present disclosure, the natural oxide film17a1or the reduction preventing film17cmay be located only in a portion of the surface that is proximate to the reducing atmosphere and contacting the fixing material13, and the covering material17bmay be located in a portion proximate to the air.

For example, as illustrated inFIG.7, the natural oxide film17a1may be located on the internal space22side of the surface contacting the fixing material13of the end current collector17, and the covering material17bmay be located on an external space23side thereof.FIG.7is an enlarged cross-sectional view illustrating the end current collector17according to a modified example 4 of the embodiment.

In the modified example 4 illustrated inFIG.7, a surface roughness Ra of a surface17a2of the natural oxide film17a1may be greater than the surface roughness Ra of a surface17b1of the covering material17b, the surface17a2and the surface17b1each contacting the fixing material13.

Thus, the adhesion force between the end current collector17and the fixing material13can be enhanced on a reducing atmosphere side (i.e., the internal space22side), which is prone to peeling, by increasing the surface roughness Ra of the surface17a2of the natural oxide film17a1, the surface17a2contacting the fixing material13.

Additionally, the diffusion of Cr from the base material17ainto the fixing material13on an oxidizing atmosphere side (i.e., the external space23side), which is prone to diffusion of Cr, can be suppressed by reducing the surface roughness Ra of the surface17b1of the covering material17b, the surface17b1contacting the fixing material13.

Thus, the modified example 4 can enhance the durability of the end current collector17, and can thereby enhance the durability of the cell stack device10.

Further, in the modified example 4, an area S1of the surface17a2of the natural oxide film17a1may be smaller than an area S2of the surface17b1of the covering material17b, the surface17a2and the surface17b1each contacting the fixing material13.

This allows, during high temperature operation, for suppression of leakage of the fuel gas due to peeling of the end current collector17from the fixing material13, as well as for suppression of separation of Cr contained in the base material17ainto the oxidizing atmosphere (external space23) through the covering material17b.

Thus, the modified example 4 can enhance the durability of the end current collector17, and can thereby enhance the durability of the cell stack device10.

FIG.8is an enlarged cross-sectional view illustrating the end current collector17according to a modified example 5 of the embodiment. As illustrated inFIG.8, in the modified example 5, the covering material17bmay include a surface17b3that is located on a side of an end (lower end portion)17b2of the covering material17band connects the surface17a2of the natural oxide film17a1and the surface17b1of the covering material17b. The surface17b3is, for example, a tapered surface inclined with respect to the surface17b1of the covering material17b.

Thus, the covering material17bhaving the surface17b3increases the contact area between the covering material17band the fixing material13. This can enhance the durability of the end current collector17, and can thereby enhance the durability of the cell stack device10.

FIG.9is an enlarged cross-sectional view illustrating the end current collector17according to a modified example 6 of the embodiment. As illustrated inFIG.9, in the modified example 6, the covering material17bmay include a protruding portion17b4that is located on the end (lower end portion)17b2side of the covering material17band protrudes away from the end current collector17to face the fixing material13.

Thus, the covering material17bhaving the protruding portion17b4increases the contact area between the covering material17band the fixing material13. This can enhance the durability of the end current collector17, and can thereby enhance the durability of the cell stack device10.

Note that whileFIGS.8and9respectively illustrate the covering material17bincluding the surface17b3or the protruding portion17b4, the covering material17bmay include the surface17b3and the protruding portion17b4.

FIG.10is a cross-sectional view illustrating the end current collector17according to a modified example 7 of the embodiment. While the aforementioned embodiment and modified examples 1 to 6 each illustrate a configuration in which a portion of the end current collector17is exposed to the internal space22, the end current collector17may not necessarily be exposed to the internal space22.

FIG.10illustrates a configuration in which the entire surface of the end current collector17is covered with the covering material17bwith an end (the lower end portion in the drawing) of the end current collector17remaining inside the fixing material13and not protruding from the fixing material13into the internal space22.

By not exposing the end current collector17to the reducing atmosphere (internal space22), reduction of manganese, which is the constituent element of the covering material17b, and separation thereof from the covering material17bcan be suppressed. Thus, the modified example 7 can enhance the durability of the end current collector17, and can thereby enhance the durability of the cell stack device10.

Further, the modified example 7 requires no etching processing or the like after the formation of the covering material17ball over the surface of the base material17a, and thus allows for low-cost manufacturing of the end current collector17.

FIG.11is a cross-sectional view illustrating the end current collector17according to a modified example 8 of the embodiment. As illustrated inFIG.11, the end current collector17according to the modified example 8 includes the surface contacting the fixing material13covered with a film different from the covering material17b. For example, in the example ofFIG.11, the surface contacting the fixing material13is covered with the natural oxide film17a1of the base material17a.

By covering the surface contacting the fixing material13with a film different from the covering material17b, generation of cracks and the like in the covering material17bdue to manganese, which is the constituent element of the covering material17b, being diffused during high temperature operation into the fixing material13, which is a glass material, can be suppressed.

Thus, the modified example 8 can further enhance the durability of the end current collector17, and can thereby enhance the durability of the cell stack device10.

FIG.12is a cross-sectional view illustrating the end current collector17according to a modified example 9 of the embodiment. While the aforementioned example ofFIG.11illustrates a configuration in which the surface contacting the fixing material13is covered with the natural oxide film17a1, the film covering the surface contacting the fixing material13is not limited to the natural oxide film17a1.

For example, as illustrated inFIG.12, the surface contacting the fixing material13may be covered with the reduction preventing film17c. This allows generation of cracks and the like in the covering material17bdue to manganese, which is the constituent element of the covering material17b, being diffused during high temperature operation into the fixing material13, which is a glass material, to be suppressed.

Thus, the modified example 9 can further enhance the durability of the end current collector17, and can thereby enhance the durability of the cell stack device10.

Module

Next, a module80according to the embodiment of the present disclosure using the cell stack device10described above will be described with reference toFIG.13.FIG.13is an exterior perspective view illustrating the module80according to an embodiment, and illustrates a state in which a front surface and a rear surface, which are parts of a housing81, are removed and the cell stack device10housed therein is extracted to the rear.

As illustrated inFIG.13, the module80includes the housing81and the cell stack device10housed in the housing81. A reformer82is disposed above the cell stack device10.

The reformer82generates a fuel gas by reforming a raw fuel such as natural gas and kerosene, and supplies the fuel gas thus generated to the cell1. The raw fuel is supplied to the reformer82through a raw fuel supply pipe83. The reformer82may include a vaporizing unit82afor vaporizing water and a reforming unit82b.

The reforming unit82bincludes a reforming catalyst (not illustrated) and reforms the raw fuel into the fuel gas. The reformer82can perform steam reforming, which is a highly efficient reforming reaction.

The fuel gas generated by the reformer82is supplied to the gas flow paths2a(seeFIG.1A) of the cell1through the gas circulation pipe20, the gas tank16, and the fixing member12.

Furthermore, in the module80having the configuration described above, the temperature in the module80during normal power generation is approximately from 500° C. to 1000° C. due to combustion of the gas and power generation by the cells1.

As described above, the module80can be configured to house the cell stack device10having high durability, resulting in the module80having high durability.

Module Housing Device

FIG.14is an exploded perspective view illustrating an example of a module housing device90according to an embodiment. The module housing device90according to the embodiment includes an external case91, the module80illustrated inFIG.13, and an auxiliary device (not illustrated). The auxiliary device operates the module80. The module80and the auxiliary device are housed in the external case91. Note that parts of the configuration are omitted inFIG.14.

The external case91of the module housing device90illustrated inFIG.14includes columns92and an external plate93. A dividing plate94divides the inside of the external case91into upper and lower portions. The space above the dividing plate94in the external case91is a module housing chamber95for housing the module80, and the space below the dividing plate94in the external case91is an auxiliary device housing chamber96for housing the auxiliary device, which operates the module80. Note thatFIG.14does not illustrate the auxiliary device housed in the auxiliary device housing chamber96.

The dividing plate94includes an air distribution hole97for causing air in the auxiliary device housing chamber96to flow toward the module housing chamber95. The external plate93forming the module housing chamber95includes an exhaust hole98for exhausting air in the module housing chamber95.

As described above, the module housing device90can be provided with the module80having high durability in the module housing chamber95, resulting in the module housing device90having high durability.

While the present disclosure has been described in detail, the present disclosure is not limited to the aforementioned embodiments, and various changes, improvements, and the like can be made without departing from the gist of the present disclosure.

The present embodiment has exemplified a vertically striped cell stack device including “vertically striped” cells arrayed on a surface of the support substrate, the cells each being provided with only one power generating element part including the fuel electrode, the solid electrolyte layer, and the air electrode. The present disclosure can be applied to a horizontally striped cell stack device including “horizontally striped” cells. The horizontally striped cell stack device includes the power generating element part at each of a plurality of locations apart from each other on the support substrate, and the power generating element parts adjacent to each other are electrically connected to each other.

The present embodiment has also exemplified a case where a hollow flat plate-shaped support substrate is used. The present disclosure can also be applied to a cell stack device using a cylindrical-shaped support substrate. The present disclosure can also be applied to a flat plate-shaped cell stack device in which “flat plate-shaped” cells are arrayed in the thickness direction.

Furthermore, the aforementioned embodiment illustrates an example in which a fuel electrode is provided on a support substrate and an air electrode is disposed on a surface of a cell. The present disclosure can also be applied to an opposite arrangement, that is, a cell stack device in which an air electrode is provided on a support substrate and a fuel electrode is disposed on a surface of a cell.

The “cell”, the “cell stack device”, the “module”, and the “module housing device”, which are exemplified in the aforementioned embodiment by a fuel cell, a fuel cell stack device, a fuel cell module, and a fuel cell device, respectively, may also be exemplified by an electrolytic cell, an electrolytic cell stack device, an electrolytic module, and an electrolytic device, respectively.

As described above, the cell stack device10according to the embodiment includes the cell stack11and the end current collector17. The cell stack11includes the plurality of cells1arrayed therein. The end current collector17is located in an end portion of the cell stack11in the array direction of the plurality of cells1. The end current collector17includes the surface exposed to the oxidizing atmosphere (external space23) covered with the covering material17bcontaining manganese and the surface exposed to the reducing atmosphere (internal space22) covered with a film different from the covering material17b. This can enhance the durability of the cell stack device10.

The cell stack device10according to the embodiment further includes the fixing material13that fixes the cells1and the end current collector17. The end current collector17includes the surface contacting the fixing material13covered with a film different from the covering material17b. This can further enhance the durability of the cell stack device10.

The cell stack device10according to the embodiment further includes the fixing material13that fixes the cells1and the end current collector17. On the surface contacting the fixing material13in the end current collector17, the covering material17band a film different from the covering material17bare provided. This can enhance the durability of the cell stack device10.

In the cell stack device10according to the embodiment, the surface roughness of the film different from the covering material17b, the film being located on the surface contacting the fixing material13in the end current collector17, is greater than the surface roughness of the covering material17blocated on the surface contacting the fixing material13in the end current collector17. This can enhance the durability of the cell stack device10.

In the cell stack device10according to the embodiment, the area S1of the film different from the covering material17b, the film being located on the surface contacting the fixing material13in the end current collector17, is smaller than the area S2of the covering material17blocated on the surface contacting the fixing material13in the end current collector17. This can enhance the durability of the cell stack device10.

In the cell stack device10according to the embodiment, the end current collector17is constituted by stainless steel, and the film different from the covering material17bis the natural oxide film17a1located on the surface of the stainless steel. This can enhance the durability of the cell stack device10, and allows for low-cost manufacturing of the end current collector17.

In the cell stack device10according to the embodiment, a film different from the covering material17bis the reduction preventing film17c. This can enhance the durability of the cell stack device10, and can also enhance the performance of the end current collector17.

The cell stack device10according to the embodiment includes the cell stack11and the end current collector17. The cell stack11includes the plurality of cells1arrayed therein. The end current collector17is located in an end portion of the cell stack11in the array direction of the plurality of cells1. The end current collector17is not exposed to the reducing atmosphere (internal space22). This can enhance the durability of the cell stack device10.

In the cell stack device10according to the embodiment, the end current collector17is covered with the covering material17bcontaining manganese. This can enhance the durability of the cell stack device10, and allows for low-cost manufacturing of the end current collector17.

The cell stack device10according to the embodiment further includes the fixing material13that fixes the cells1and the end current collector17. The end current collector17includes the surface exposed to the oxidizing atmosphere (external space23) covered with the covering material17bcontaining manganese, and in the end current collector17, the surface contacting the fixing material13covered with a film different from the covering material17b. This can further enhance the durability of the cell stack device10.

The module80according to the embodiment includes the aforementioned cell stack device10housed in the housing81. This can yield the module80having high durability.

The module housing device90according to the embodiment includes the aforementioned module80and the auxiliary device for operating the module80, both of which are housed in the external case91. This can yield the module housing device90having high durability.

The metal member (end current collector17) according to the embodiment includes the surface exposed to the oxidizing atmosphere (external space23) and the surface exposed to the reducing atmosphere (internal space22). The surface exposed to the oxidizing atmosphere (external space23) is covered with the covering material17bcontaining manganese, and the surface exposed to the reducing atmosphere (internal space22) is covered with a film different from the covering material17b. This can enhance the durability of the end current collector17.

The embodiment disclosed herein is considered exemplary in all respects and not restrictive. Indeed, the aforementioned embodiment can be embodied in a variety of forms. Furthermore, the aforementioned embodiment may be omitted, replaced, or changed in various forms without departing from the scope of the appended claims and the purpose thereof.