Patent Description:
In recent years, various fuel cell stack devices have been proposed as next-generation energy sources in which a plurality of fuel cells are arranged, each of the fuel cells being a type of cell capable of generating electrical power by using a fuel gas (hydrogen-containing gas) and an oxygen-containing gas (air).

In such a fuel cell stack device, for example, lower ends of the plurality of fuel cells are bonded to a holding member by a fixing material (see Patent Document <NUM>).

Patent Document <NUM>: <CIT>
Moreover, <CIT> discloses a fuel cell stack assembly comprising a plurality of serially-assembled fuel cell stages formed as individual cassette units and <CIT> discloses methods for diminishing or preventing in electrochemical operating systems the deposition of a metal oxide on an electrode surface.

The present invention provides a fuel or electrolytic cell stack device according to claim <NUM>, a module according to claim <NUM>, and a module housing device according to claim <NUM>. Preferred embodiments are described in the dependent claims.

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

Furthermore, it is noted that the drawings are schematic and the dimensional relationship between elements, the proportions of elements, and the like may differ from realistic ones. Even between the drawings, there may be a case where portions having different dimensional relationships, proportions, and the like from one another are included.

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 to <FIG>.

<FIG> is a cross-sectional view illustrating an example of a cell <NUM> according to an embodiment, <FIG> is a side view illustrating an example of the cell <NUM> according to the embodiment when viewed from an air electrode <NUM> side, and <FIG> is a side view illustrating an example of the cell <NUM> according to the embodiment when viewed from an interconnector <NUM> side. <FIG> illustrate an enlarged part of each configuration of the cell <NUM>.

In the example illustrated in <FIG>, the cell <NUM> is of a hollow flat plate type and has an elongated plate shape. As illustrated in <FIG>, the shape of the entire cell <NUM> when viewed from the side is, for example, a rectangle having a side length of <NUM> to <NUM> in a length direction L and a length of <NUM> to <NUM> in a width direction W orthogonal to the length direction L. The total length (thickness direction T) of the cell <NUM> is <NUM> to <NUM>.

As illustrated in <FIG>, the cell <NUM> includes a support substrate <NUM> that is conductive, an element part, and the interconnector <NUM>. The support substrate <NUM> has a columnar shape having a pair of opposing first flat surface n1 and second flat surface n2, and a pair of arc-shaped side surfaces m that connect the first flat surface n1 and the second flat surface n2.

The element part is provided on the first flat surface n1 of the support substrate <NUM>. The element part has a fuel electrode <NUM>, a solid electrolyte layer <NUM>, and an air electrode <NUM>. In the example illustrated in <FIG>, the interconnector <NUM> is provided on the second flat surface n2 of the cell <NUM>.

As illustrated in <FIG>, the air electrode <NUM> does not extend to a lower end of the cell <NUM>. At the lower end of the cell <NUM>, only the solid electrolyte layer <NUM> is exposed on a surface of the first flat surface n1. As illustrated in <FIG>, the interconnector <NUM> may extend to the lower end of the cell <NUM>. At the lower end of the cell <NUM>, the interconnector <NUM> and the solid electrolyte layer <NUM> are exposed on the surface. As illustrated in <FIG>, the solid electrolyte layer <NUM> is exposed on surfaces of the pair of arc-shaped side surfaces m of the cell <NUM>. The interconnector <NUM> need not extend to the lower end of the cell <NUM>.

Hereinafter, respective constituent members constituting the cell <NUM> will be described.

The support substrate <NUM> is provided therein with gas flow paths 2a through which a gas flows. <FIG> illustrates an example in which the support substrate <NUM> has six gas flow paths 2a extending along the length direction. The support substrate <NUM> has gas permeability and allows fuel gas to permeate to the fuel electrode <NUM>. The support substrate <NUM> illustrated in <FIG> has conductivity. The support substrate <NUM> can collect electricity generated in the element part via the interconnector <NUM>.

The material of the support substrate <NUM> contains, for example, an iron group metal component and an inorganic oxide. For example, the iron group metal component may be Ni and/or NiO. For example, the inorganic oxide may be a specific rare earth element oxide.

As the material of the fuel electrode <NUM>, a generally known material may be used. The fuel electrode <NUM> can be formed from 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 ZrO<NUM> and Ni and/or NiO. As the rare earth element oxide, for example, Y<NUM>O<NUM> or the like is used. Hereinafter, a solid solution of a calcium oxide, a magnesium oxide, or a rare earth element oxide in ZrO<NUM> is referred to as stabilized zirconia. In the present disclosure, stabilized zirconia also includes partially stabilized zirconia.

The solid electrolyte layer <NUM> is an electrolyte and bridges ions between the fuel electrode <NUM> and the air electrode <NUM>. At the same time, the solid electrolyte layer <NUM> has a gas blocking property and makes it difficult for fuel gas and oxygen-containing gas to leak.

The material of the solid electrolyte layer <NUM> is, for example, a solid solution of <NUM> mol% to <NUM> mol% of a rare earth element oxide in ZrO<NUM>. As the rare earth element oxide, for example, Y<NUM>O<NUM> or the like is used. Another material may be used as the material of the solid electrolyte layer <NUM> as long as it has the above characteristics.

The material of the air electrode <NUM> is not particularly limited as long as it is generally used for an air electrode. The material of the air electrode <NUM> may be, for example, a conductive ceramic such as a so-called ABO<NUM> type perovskite type oxide.

The material of the air electrode <NUM> may be, for example, a composite oxide in which Sr and La coexist in the A site. Examples of such a composite oxide include LaxSr<NUM>-xCoyFe<NUM>-yO<NUM>, LaxSr<NUM>-xMnO<NUM>, LaxSr<NUM>-xFeO<NUM>, LaxSr<NUM>-xCoO<NUM>, and the like. Here, x is <NUM><x<<NUM> and y is <NUM><y<<NUM>.

Furthermore, the air electrode <NUM> has gas permeability. The open porosity of the air electrode <NUM> may be <NUM>% or more, and is particularly in the range of <NUM>% to <NUM>%.

As the material of the interconnector <NUM>, a lanthanum chromite-based perovskite type oxide (LaCrO<NUM>-based oxide), a lanthanum strontium titanium-based perovskite type oxide (LaSrTiO<NUM>-based oxide), or the like may be used. These materials have conductivity, and are neither reduced nor oxidized even when they come into contact with a fuel gas such as a hydrogen-containing gas, and an oxygen-containing gas such as air.

Furthermore, the interconnector <NUM> is dense and makes it difficult for the fuel gas flowing through the gas flow paths 2a formed in the support substrate <NUM> and the oxygen-containing gas flowing outside the support substrate <NUM> to leak. The interconnector <NUM> may have a relative density of <NUM>% or more, particularly <NUM>% or more.

Next, a cell stack device <NUM> according to the present embodiment using the aforementioned cell <NUM> will be described with reference to <FIG>. <FIG> is a perspective view illustrating an example of the cell stack device <NUM> according to the embodiment, <FIG> is a cross-sectional view taken along line X-X illustrated in <FIG>, and <FIG> is a top view illustrating an example of the cell stack device <NUM> according to the embodiment.

As illustrated in <FIG>, the cell stack device <NUM> includes a cell stack <NUM> having a plurality of cells <NUM> arranged (stacked) in the thickness direction T (see <FIG>) of the cells <NUM>, and a fixing member <NUM>.

The fixing member <NUM> has a fixing material <NUM> and a holding member <NUM>. The holding member <NUM> holds the cells <NUM>. The fixing material <NUM> fixes the cells <NUM> to the holding member <NUM>. Furthermore, the holding member <NUM> has a holding body <NUM> and a gas tank <NUM>. The holding body <NUM> and the gas tank <NUM>, which constitute the holding member <NUM>, are made of metal and have conductivity.

As illustrated in <FIG>, the holding body <NUM> has an insertion hole 15a into which the lower ends of the plurality of cells <NUM> are inserted. The lower ends of the plurality of cells <NUM> and the inner wall of the insertion hole 15a are bonded by the fixing material <NUM>.

The gas tank <NUM> has an opening for supplying a reaction gas to the plurality of cells <NUM> via the insertion hole 15a and a recessed groove 16a provided around the opening. An outer peripheral end of the holding body <NUM> is bonded to the gas tank <NUM> by a bonding material <NUM> filled in the recessed groove 16a of the gas tank <NUM>.

In the example illustrated in <FIG>, the fuel gas is stored in an internal space formed by the holding body <NUM> and the gas tank <NUM>, which constitute the holding member <NUM>. A gas circulation pipe <NUM> is connected to the gas tank <NUM>. The fuel gas is supplied to the gas tank <NUM> through the gas circulation pipe <NUM>, and is supplied from the gas tank <NUM> to the gas flow paths 2a (see <FIG>) inside the cells <NUM>. The fuel gas supplied to the gas tank <NUM> is generated by a reformer <NUM> (see <FIG>) to be described below.

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

The example illustrated in <FIG> includes two rows of cell stacks <NUM>, two holding bodies <NUM>, and the gas tank <NUM>. Each of the two rows of cell stacks <NUM> has a plurality of cells <NUM>. Each of the cell stacks <NUM> is fixed to a corresponding one of the holding bodies <NUM>. The gas tank <NUM> has two through holes on the upper surface thereof. Each of the holding bodies <NUM> is disposed in a corresponding one of the through holes. The internal space is formed by one gas tank <NUM> and two holding bodies <NUM>.

The insertion hole 15a has, for example, an oval shape in the top view. The length of the insertion hole 15a, for example, in the arrangement direction of the cells <NUM>, that is, the thickness direction T, is larger than a distance between two end current collection members <NUM> located at both ends of the cell stack <NUM>. The width of the insertion hole 15a is, for example, larger than the length of the cell <NUM> in the width direction W (see <FIG>).

As illustrated in <FIG>, the fixing material <NUM> is filled in the bonding portion between the inner wall of the insertion hole 15a and the lower end of the cell <NUM> and is solidified. Consequently, the inner wall of the insertion hole 15a and the lower ends of the plurality of cells <NUM> are bonded and fixed, respectively, and the lower ends of the cells <NUM> are bonded and fixed to each other. The gas flow path 2a of each of the cells <NUM> communicates with the internal space of the holding member <NUM> at the lower end.

The fixing material <NUM> and the bonding material <NUM> have oxide ion conductivity. The fixing material <NUM> and the bonding material <NUM> can use a material having lower conductivity. As a specific material of the fixing material <NUM> and the bonding material <NUM>, amorphous glass or the like may be used, or particularly, crystallized glass or the like may be used.

As the crystallized glass, for example, any of SiO<NUM>-CaO-based, MgO-B<NUM>O<NUM>-based, La<NUM>O<NUM>-B<NUM>O<NUM>-MgO-based, La<NUM>O<NUM>-B<NUM>O<NUM>-ZnO-based, and SiO<NUM>-CaO-ZnO-based materials may be used, or, particularly, a SiO<NUM>-MgO-based material may be used.

As illustrated in <FIG>, a conductive member <NUM> for electrically connecting adjacent ones of the cells <NUM> in series is interposed between adjacent ones of the cells <NUM>. More specifically, the space between the adjacent ones of the cells <NUM> corresponds to the space between the fuel electrode <NUM> of one of the adjacent cells <NUM> and the air electrode <NUM> of the other one of the adjacent cells <NUM>.

As illustrated in <FIG>, the end current collection members <NUM> are connected to the outermost ones of the cells <NUM> in the arrangement direction of the plurality of cells <NUM>. The end current collection member <NUM> is connected to a conductive part <NUM> protruding outward from the cell stack <NUM>. The conductive part <NUM> has a function of collecting electricity generated by power generation of the cells <NUM> and sending the collected electricity to the outside. <FIG> does not illustrate the end current collection members <NUM>.

As illustrated in <FIG>, in the cell stack device <NUM>, two cell stacks 11A and 11B are connected in series and function as one battery. Therefore, the conductive part <NUM> of the cell stack device <NUM> is divided into a positive electrode terminal 19A, a negative electrode terminal 19B, and a connection terminal 19C.

The positive electrode terminal 19A functions as a positive electrode when power generated by the cell stack <NUM> is output to the outside, and is electrically connected to the end current collection members <NUM> on a positive electrode side in the cell stack 11A. The negative electrode terminal 19B functions as a negative electrode when power generated by the cell stack <NUM> is output to the outside, and is electrically connected to the end current collection members <NUM> on a negative electrode side in the cell stack 11B.

The connection terminal 19C electrically connects the end current collection members <NUM> on the negative electrode side in the cell stack 11A and the end current collection members <NUM> on the positive electrode side in the cell stack 11B.

A reference example illustrated in <FIG> will be described. <FIG> is a diagram illustrating an example of a power system <NUM> including the cell stack device <NUM> of the reference example, and <FIG> is a diagram illustrating an example of a magnitude relationship of potentials of respective parts in the cell stack device <NUM> of the reference example. Furthermore, <FIG> and <FIG> are diagrams for explaining a phenomenon occurring in the cell stack device <NUM> of the reference example.

As illustrated in <FIG>, the power system <NUM> connects the cell stack device <NUM> to a power conditioning subsystem (PCS) <NUM>, and supplies power generated by the cell stack device <NUM> to a power system <NUM> via the PCS <NUM>.

Specifically, the PCS <NUM> converts DC power generated by the cell stack device <NUM> into AC power, and supplies the AC power to the power system <NUM>. Therefore, both the positive electrode terminal 19A and the negative electrode terminal 19B of the cell stack device <NUM> are connected to the PCS <NUM>.

Furthermore, in the power system <NUM> illustrated in <FIG>, as illustrated in <FIG>, when the electromotive force of the cell stack device <NUM> is set to 2A (V), the potential of the positive electrode terminal 19A is +A (V) and the potential of the negative electrode terminal 19B is -A (V). The electromotive force of the cell stack device <NUM> is, in other words, the electromotive force of the cell stack <NUM>.

Furthermore, the holding member <NUM> made of metal and having conductivity is grounded in order to ensure stable operation of the cell stack device <NUM>. The holding member <NUM> includes the holding body <NUM> and the gas tank <NUM>. That is, the potential of the holding body <NUM> (holding member <NUM>) is <NUM> (V). The potential of the holding body <NUM> may be a potential slightly deviated from the just intermediate potential between the potential of the positive electrode terminal 19A and the potential of the negative electrode terminal 19B.

Due to such a magnitude relation of the potentials, as illustrated in <FIG>, a potential difference occurs between the cell <NUM> in the vicinity of the positive electrode terminal 19A having a potential of approximately +A (V) and the holding body <NUM> having a potential of <NUM> (V).

Due to such a potential difference, as illustrated in <FIG>, oxygen ions (O<NUM>-) in an oxide film formed on the surface of the holding body <NUM> are attracted to the cell <NUM> side, and metal ions (M+) in the oxide film are attracted to the holding body <NUM> side. That is, a reduction reaction of the oxide film occurs in an interface between the fixing material <NUM> and the holding body <NUM>.

Consequently, this causes a loss of the oxide film on the surface of the holding body <NUM> in the interface with the fixing material <NUM>, and such a loss causes a gap C to be formed between the fixing material <NUM> and the holding body <NUM> as illustrated in <FIG>. The formation phenomenon of the gap C is likely to occur between the cell <NUM> in the vicinity of the positive electrode terminal 19A and the holding body <NUM> between which there is a large potential difference, and the formation of such a gap C may reduce the durability of the cell stack device <NUM>.

The holding body <NUM> may be a flat plate-shaped holding body <NUM> as illustrated in <FIG>. In such a case, for example, an internal space is formed by bonding the gas tank <NUM> to the lower surface or side surface of the holding body <NUM> that has a flat plate shape. Furthermore, as illustrated in <FIG>, the holding body <NUM> may be a holding body <NUM> having a plurality of insertion holes 15a. In such a case, the cells <NUM> may be inserted into the plurality of insertion holes 15a of the holding body <NUM> in a one-to-one manner, or a plurality of cells <NUM> may be inserted into each of the plurality of insertion holes 15a of the holding body <NUM>. <FIG> is a cross-sectional view of a bonding portion between the holding body <NUM> that has a flat plate shape and the cell <NUM>. Furthermore, the holding body <NUM> may be integrally formed with the gas tank <NUM>. Even in such a holding body <NUM>, the gap C is formed between the fixing material <NUM> and the holding body <NUM>.

Subsequently, the cell stack device <NUM> according to the embodiment will be described with reference to <FIG> and <FIG>. <FIG> is a diagram illustrating an example of the power system <NUM> including the cell stack device <NUM> according to the embodiment, and <FIG> is a diagram illustrating a magnitude relationship of potentials of respective parts in the cell stack device <NUM> according to the embodiment.

As illustrated in <FIG>, in the power system <NUM> according to the embodiment, the positive electrode terminal 19A of the cell stack device <NUM> and the PCS <NUM> are connected to a ground potential <NUM> via a noise reduction unit <NUM>. That is, in the cell stack device <NUM> according to the embodiment, the positive electrode terminal 19A is grounded by being connected to the ground potential <NUM>.

Consequently, as illustrated in <FIG>, the potential of the positive electrode terminal 19A can be set to <NUM> (V), which is the same as that of the holding body <NUM> (holding member <NUM>). In such a case, the potential of the negative electrode terminal 19B is -2A (V).

That is, in the embodiment, there is no potential difference between the cell <NUM> in the vicinity of the positive electrode terminal 19A and the holding body <NUM> described in the above reference example, which makes it possible to prevent a reduction reaction from occurring in the interface between the fixing material <NUM> and the holding body <NUM>.

Consequently, according to the embodiment, it is possible to reduce the loss of the oxide film on the surface of the holding body <NUM> in the interface with the fixing material <NUM>. As a consequence, the gap C is not easily formed between the fixing material <NUM> and the holding body <NUM>. That is, according to the embodiment, it is possible to improve the durability of the cell stack device <NUM>.

Furthermore, in the embodiment, the noise reduction unit <NUM> may be provided between the positive electrode terminal 19A and the ground potential <NUM>. In the noise reduction unit <NUM>, for example, a coil 32a and a resistor 32b are connected in series between the positive electrode terminal 19A and the ground potential <NUM>, and a capacitor 32c is connected in parallel with the resistor 32b.

In the embodiment, by providing the noise reduction unit <NUM> between the positive electrode terminal 19A and the ground potential <NUM>, it is possible to reduce noise included in DC power supplied from the cell stack device <NUM>. Consequently, according to the embodiment, the PCS <NUM> can stably convert DC power into AC power.

The circuit configuration of the noise reduction unit <NUM> illustrated in <FIG> is merely an example and other circuit configurations can also be adopted.

Subsequently, the cell stack device <NUM> according to a first modification of the embodiment will be described with reference to <FIG> and <FIG>. <FIG> is a diagram illustrating an example of the power system <NUM> including the cell stack device <NUM> according to the first modification of the embodiment, and <FIG> is a diagram illustrating a magnitude relationship of potentials of respective parts in the cell stack device <NUM> according to the first modification of the embodiment.

The first modification is different from the embodiment in that a separate battery <NUM> is provided between the positive electrode terminal 19A and the ground potential <NUM>. A positive electrode of the battery <NUM> is connected to the ground potential <NUM> via the noise reduction unit <NUM>. Furthermore, a negative electrode of the battery <NUM> is connected to the positive electrode terminal 19A.

As illustrated in <FIG>, when the electromotive force of the battery <NUM> is B (V), the potential of the positive electrode terminal 19A can be set to -B (V) lower than the potential <NUM> (V) of the holding body <NUM> (holding member <NUM>). In such a case, the potential of the negative electrode terminal 19B is -B-2A (V).

That is, in the first modification, since a potential difference opposite to the potential difference described in the above reference example can be generated, an oxidation reaction opposite to the reduction reaction can occur in the interface between the fixing material <NUM> and the holding body <NUM>.

Consequently, even though the oxide film on the surface of the holding body <NUM> in the interface with the fixing material <NUM> may grow due to the oxidation reaction, it is possible to reduce the loss of the oxide film. Therefore, according to the first modification, the gap C is not easily formed between the fixing material <NUM> and the holding body <NUM>, which makes it possible to improve the durability of the cell stack device <NUM>.

The battery <NUM> is an example of a negative voltage application unit that applies a negative voltage to the positive electrode terminal 19A. That is, such a negative voltage application unit is not limited to the battery <NUM>, and may have any configuration as long as it can apply a negative voltage to the positive electrode terminal 19A with respect to the ground potential <NUM>.

Furthermore, in the first modification, the noise reduction unit <NUM> may be provided between the positive electrode terminal 19A and the ground potential <NUM> as in the embodiment. With this, it is possible to reduce noise included in DC power supplied from the cell stack device <NUM>, and thus the PCS <NUM> can stably convert DC power into AC power.

Next, a module <NUM> according to the embodiment of the present disclosure using the cell stack device <NUM> described above will be described with reference to <FIG> is an external appearance perspective view illustrating the module <NUM> according to the embodiment, and illustrates a state in which a front surface and a rear surface, which are a part of a housing container <NUM>, are taken out and the cell stack device <NUM> of a fuel cell housed inside is taken out to the rear.

As illustrated in <FIG>, the module <NUM> includes the housing container <NUM> and the cell stack device <NUM> housed in the housing container <NUM>. The reformer <NUM> is disposed above the cell stack device <NUM>.

The reformer <NUM> generates fuel gas by reforming raw fuel such as natural gas and kerosene, and supplies the generated fuel gas to the cell <NUM>. The raw fuel is supplied to the reformer <NUM> through a raw fuel supply pipe <NUM>. The reformer <NUM> may include a vaporizing part 82a for vaporizing water and a reforming part 82b. The reforming part 82b includes a reforming catalyst (not illustrated) and reforms the raw fuel into the fuel gas. The reformer <NUM> such as that described above can perform steam reforming which is a highly efficient reforming reaction.

The fuel gas generated by the reformer <NUM> is supplied to the gas flow paths 2a (see <FIG>) of the cell <NUM> through the gas circulation pipe <NUM>, the gas tank <NUM>, and the fixing member <NUM>.

Furthermore, in the module <NUM> having the configuration described above, the temperature in the module <NUM> during normal power generation is <NUM> to <NUM>,<NUM> due to the combustion of gas and power generation of the cells <NUM>.

In the module <NUM> such as that described above, by providing the cell stack device <NUM> having high durability, which is less likely to form the gap C as described above, the module <NUM> having high durability can be acquired.

<FIG> is an exploded perspective view illustrating an example of a module housing device <NUM> according to the embodiment. The module housing device <NUM> according to the embodiment includes an outer case, the module <NUM> illustrated in <FIG>, and an auxiliary device (not illustrated). The auxiliary device operates the module <NUM>. The module <NUM> and the auxiliary device are housed in the outer case. <FIG> does not illustrate a part of the configuration.

The outer case of the module housing device <NUM> illustrated in <FIG> has columns <NUM> and an outer plate <NUM>. A partition plate <NUM> vertically divides the inside of the outer case. The space above the partition plate <NUM> in the outer case is a module housing chamber <NUM> for housing the module <NUM>, and the space below the partition plate <NUM> in the outer case is an auxiliary device housing chamber <NUM> for hosuing the auxiliary device that operates the module <NUM>. <FIG> does not illustrate the auxiliary device that is housed in the auxiliary device housing chamber <NUM>.

Furthermore, the partition plate <NUM> has an air circulation port <NUM> for causing the air in the auxiliary device housing chamber <NUM> to flow toward the module housing chamber <NUM>. The outer plate <NUM> constituting the module housing chamber <NUM> has an exhaust port <NUM> for exhausting the air in the module housing chamber <NUM>.

In the module housing device <NUM> such as that described above, by providing the module housing chamber <NUM> with the module <NUM> having high durability as described above, the module housing device <NUM> having high durability can be acquired.

So far, although the present disclosure has been described in detail, the present disclosure is not limited to the aforementioned embodiment.

The aforementioned embodiment has exemplified a vertical stripe type cell stack device in which so-called "vertical stripe type" cells are stacked, the cells being provided with only one power generation element part including a fuel electrode, a solid electrolyte layer, and an air electrode on the surface of a support substrate. The present disclosure can be applied to a horizontal stripe type cell stack device in which so-called "horizontal stripe type" cells are stacked, the cells including power generation element parts provided at a plurality of locations separate from each other on the surface of a support substrate, adjacent power generation element parts being electrically connected to each other.

Furthermore, the aforementioned embodiment has exemplified the case where a hollow flat plate type support substrate is used. The present disclosure can also be applied to a cell stack device using a cylindrical support substrate. Furthermore, the present disclosure can also be applied to a flat plate type cell stack device in which a so-called "flat plate type" cell is stacked in the thickness direction.

Furthermore, the aforementioned embodiment gives an example in which a fuel electrode is provided on a support substrate and an air electrode is disposed on the 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 the surface of a cell.

Furthermore, in the aforementioned embodiment, a fuel cell, a fuel cell stack device, a fuel cell module, and a fuel cell device are illustrated as examples of the "cell", the "cell stack device", the "module", and the "module housing device"; however, in other examples, an electrolytic cell, an electrolytic cell stack device, an electrolytic module, and an electrolytic device may be the "cell", the "cell stack device", the "module", and the "module housing device", respectively.

<FIG> is a cross-sectional view illustrating a cell stack device <NUM> according to a second modification of the embodiment. As illustrated in <FIG>, the cell stack device <NUM> according to the second modification includes a cell stack <NUM> in which a plurality of plate-shaped cells <NUM> are stacked. Furthermore, in the cell stack device <NUM> according to the second modification, the cell stack <NUM> is interposed between a positive-electrode-side end current collection member <NUM> and a negative-electrode-side end current collection member <NUM>.

The cell <NUM> of the second modification has an element part <NUM>, a separator <NUM>, an air-electrode-side frame <NUM>, a fuel-electrode-side frame <NUM>, an air-electrode-side current collector <NUM>, a fuel-electrode-side current collector <NUM>, and an interconnector <NUM>.

<FIG> is an enlarged cross-sectional view illustrating a structure of the cell <NUM> according to the second modification of the embodiment. As illustrated in <FIG>, the element part <NUM> of the second modification has an air electrode 202a, a solid electrolyte layer 202b located on a lower surface of the air electrode 202a, and a fuel electrode 202c located on a lower surface of the solid electrolyte layer 202b. The air electrode 202a is located on a side of the element part <NUM> in contact with the air-electrode-side current collector <NUM>, and the fuel electrode 202c is located on a side of the element part <NUM> in contact with the fuel-electrode-side current collector <NUM>.

<FIG> will be described again. The separator <NUM> is a frame-shaped member having a through hole penetrating the separator <NUM> in the vertical direction near the center thereof. The material of the separator <NUM> may be, for example, a metal. A peripheral portion of the through hole in the separator <NUM> faces a peripheral edge portion of the surface of the solid electrolyte layer 202b (see <FIG>) on a side of the air electrode 202a (see <FIG>). The separator <NUM> is bonded to the solid electrolyte layer 202b at the facing portion.

The separator <NUM> divides the cell <NUM> into an air chamber <NUM> facing the air electrode 202a and a fuel chamber <NUM> facing the fuel electrode 202c (see <FIG>), which makes it difficult for gas to leak from one electrode side to the other electrode side at the peripheral edge portion of the element part <NUM>.

The air-electrode-side frame <NUM> is a frame-shaped member having a through hole penetrating the air-electrode-side frame <NUM> in the vertical direction near the center thereof. The material of the air-electrode-side frame <NUM> may be, for example, an insulator such as mica. The air-electrode-side frame <NUM> comes into contact with a peripheral edge portion of a surface on a side of the separator <NUM>, which is opposite to a side of the separator <NUM>, which faces the solid electrolyte layer 202b, and a peripheral edge portion of a surface on a side of the interconnector <NUM>, which faces the air electrode 202a.

Since the cell <NUM> located at the uppermost position in the cell stack <NUM> does not have the upper interconnector <NUM>, the air-electrode-side frame <NUM> in the cell <NUM> comes into contact with the end current collection member <NUM>.

The through hole of the air-electrode-side frame <NUM> constitutes the air chamber <NUM> facing the air electrode 202a. Furthermore, the air-electrode-side frame <NUM> electrically insulates adjacent interconnectors <NUM> from each other.

The fuel-electrode-side frame <NUM> is a frame-shaped member having a through hole penetrating the fuel-electrode-side frame <NUM> in the vertical direction near the center thereof. The material of the fuel-electrode-side frame <NUM> may be, for example, metal. The through hole of the fuel-electrode-side frame <NUM> constitutes the fuel chamber <NUM> facing the fuel electrode 202c.

The fuel-electrode-side frame <NUM> comes into contact with a peripheral edge portion of a surface on a side of the separator <NUM>, which faces the solid electrolyte layer 202b, and a peripheral edge portion of a surface on a side of the interconnector <NUM>, which faces the fuel electrode 202c.

The air-electrode-side current collector <NUM> is disposed in the air chamber <NUM>. The air-electrode-side current collector <NUM> is composed of a plurality of columnar conductive members arranged at predetermined intervals. The material of the air-electrode-side current collector <NUM> may be, for example, stainless steel.

The air-electrode-side current collector <NUM> comes into contact with a surface on a side of the air-electrode 202a, which is opposite to a side of the air electrode 202a, which faces the solid electrolyte layer 202b, and a surface on a side of the interconnector <NUM>, which faces the air electrode 202a. Since the cell <NUM> located at the uppermost position in the cell stack <NUM> does not have the upper interconnector <NUM>, the air-electrode-side current collector <NUM> in the cell <NUM> comes into contact with the end current collection member <NUM>.

That is, the air-electrode-side current collector <NUM> electrically connects between the air electrode 202a and the interconnector <NUM>, or between the air electrode 202a and the end current collection member <NUM>. The air-electrode-side current collector <NUM> and the interconnector <NUM> may be formed as an integrated member.

The fuel-electrode-side current collector <NUM> is disposed in the fuel chamber <NUM>. The fuel-electrode-side current collector <NUM> is composed of a plurality of columnar conductive members arranged at predetermined intervals. The material of the fuel-electrode-side current collector <NUM> may be, for example, stainless steel. As illustrated in <FIG>, the fuel-electrode-side current collector <NUM> may have an electrode facing part 207a, an interconnector facing part 207b, a connection part 207c, and a spacer 207d, for example.

The electrode facing part 207a faces the fuel electrode 202c of the element part <NUM>. The interconnector facing part 207b faces the interconnector <NUM> (or the end current collection member <NUM>). The connection part 207c connects the electrode facing part 207a and the interconnector facing part 207b. The electrode facing part 207a, the interconnector facing part 207b, and the connection part 207c may all be made of metal, or may be integrally formed with one another, for example.

The spacer 207d is located between the electrode facing part 207a and the interconnector facing part 207b. The material of the spacer 207d may be, for example, mica. By disposing the spacer 207d in the fuel-electrode-side current collector <NUM>, the fuel-electrode-side current collector <NUM> can easily follow the deformation of the cell <NUM> due to a temperature cycle, a pressure fluctuation of the reaction gas, and the like.

Consequently, the cell <NUM> having the fuel-electrode-side current collector <NUM> as illustrated in <FIG> can maintain a good electrical connection between the fuel electrode 202c and the interconnector <NUM> (or the end current collection member <NUM>) via the fuel-electrode-side current collector <NUM>.

<FIG> will be described again. The interconnector <NUM> is a flat plate-shaped conductive member. The material of the interconnector <NUM> may be, for example, stainless steel. The interconnector <NUM> ensures electrical connection between adjacent ones of the cells <NUM>. Furthermore, the interconnector <NUM> makes it difficult for the reaction gas to be mixed between adjacent ones of the cells <NUM>, that is, makes it difficult for the gas to leak from one cell <NUM> side to the other cell <NUM> side. In the second modification, adjacent ones of the cells <NUM> share one interconnector <NUM>.

The cell <NUM> in contact with the end current collection member <NUM> or the end current collection member <NUM> has no interconnector <NUM> because the end current collection member <NUM> or the end current collection member <NUM> has the function of the interconnector <NUM>.

A positive electrode terminal <NUM> functions as a positive electrode when power generated by the cell stack <NUM> is output to the outside, and is electrically connected to the positive-electrode-side end current collection member <NUM> in the cell stack <NUM>. A negative electrode terminal <NUM> functions as a negative electrode when power generated by the cell stack <NUM> is output to the outside, and is electrically connected to the negative-electrode-side end current collection member <NUM> in the cell stack <NUM>.

The cell stack device <NUM> has communication holes <NUM> and <NUM> through which the end current collection member <NUM>, the cell stack <NUM>, and the end current collection member <NUM> communicate with one another, and metal bolts <NUM> are inserted into the communication holes <NUM> and <NUM>, respectively.

Furthermore, metal nuts <NUM> are fitted to the bolts <NUM> exposed to the outside from the end current collection member <NUM> and the end current collection member <NUM>, so that the plurality of cells <NUM> are held between the end current collection member <NUM> and the end current collection member <NUM>. That is, in the second modification, the bolts <NUM> and the nuts <NUM> form holding members <NUM> that hold the plurality of cells <NUM>.

A fixing material <NUM> is located between the end current collection member <NUM> and the holding member <NUM> and between the end current collection member <NUM> and the holding member <NUM>. The fixing material <NUM> of the second modification may be made of the same material as that of the fixing material <NUM> of the embodiment, for example. The fixing material <NUM> of the second modification is not limited to the same material as that of the fixing material <NUM> of the embodiment, and may be made of an insulating sheet, for example.

Either the end current collection member <NUM> or the end current collection member <NUM> may be formed with a screw hole. For example, when the end current collection member <NUM> is formed with a screw hole, the bolt <NUM> may be screwed into the screw hole. The inner wall of the screw hole and the bolt <NUM> may be in direct contact with each other, or the fixing material <NUM> may be located between the inner wall of the screw hole and the bolt <NUM>. In such a case, the bolt <NUM> is exposed to the outside from the end current collection member <NUM> and the metal nut <NUM> is fitted to the exposed bolt <NUM>. The fixing material <NUM> is located between the end current collection member <NUM> and the holding member <NUM>.

Instead of the bolt <NUM> and the nut <NUM>, a bolt having a flange portion may be used as the holding member <NUM>. The bolt having a flange portion is screwed into the screw hole of the end current collection member <NUM>, and the fixing material <NUM> is located between the flange portion of the holding member <NUM> and the end current collection member <NUM>. The screw hole may go through the end current collection member <NUM>, or may have a bottom portion without going through the end current collection member <NUM>.

<FIG> is a diagram illustrating an example of a power system 100A including the cell stack device <NUM> according to the second modification of the embodiment. As illustrated in <FIG>, in the power system 100A according to the second modification, the positive electrode terminal <NUM> of the cell stack device <NUM> and the PCS <NUM> are connected to the ground potential <NUM> via the noise reduction unit <NUM>.

That is, in the cell stack device <NUM> according to the second modification, the positive electrode terminal <NUM> is grounded by being connected to the ground potential <NUM>.

With this, as illustrated in <FIG>, the potential of the positive electrode terminal <NUM> can be set to <NUM> (V), which is the same as that of the holding member <NUM>. The positive electrode terminal <NUM> and the end current collection member <NUM> may be electrically connected to the holding member <NUM>. In such a case, the potential of the negative electrode terminal <NUM> is -2A (V).

Consequently, in the second modification, there is no potential difference between the positive electrode terminal <NUM> and the holding member <NUM> as in the embodiment, which makes it possible to prevent a reduction reaction from occurring in the interface between the fixing material <NUM> and the holding member <NUM>.

Consequently, according to the second modification, it is possible to reduce the loss of the oxide film on the surface of the holding member <NUM> in the interface with the fixing material <NUM>. As a consequence, a gap is not easily formed between the fixing material <NUM> and the holding member <NUM>. That is, according to the second modification, it is possible to improve the durability of the cell stack device <NUM>.

The power system 100A including the cell stack device <NUM> according to the second modification is not limited to the example in <FIG>. <FIG> is a diagram illustrating another example of the power system 100A including the cell stack device <NUM> according to the second modification of the embodiment.

The example in <FIG> is different from that in <FIG> in that a separate battery <NUM> is provided between the positive electrode terminal <NUM> and the ground potential <NUM>. A positive electrode of the battery <NUM> is connected to the ground potential <NUM> via the noise reduction unit <NUM>, and a negative electrode of the battery <NUM> is connected to the positive electrode terminal <NUM>.

Consequently, even in the second modification, as in the first modification described above, an oxidation reaction opposite to a reduction reaction can occur in the interface between the fixing material <NUM> and the holding member <NUM>. That is, in the example in <FIG>, even though the oxide film on the surface of the holding member <NUM> in the interface with the fixing material <NUM> grows due to the oxidation reaction, it is possible to reduce the loss of the oxide film.

Consequently, according to the example in <FIG>, a gap is not easily formed between the fixing material <NUM> and the holding member <NUM>, which makes it possible to improve the durability of the cell stack device <NUM>.

Furthermore, in the examples in <FIG> and <FIG>, the noise reduction unit <NUM> may be provided between the positive electrode terminal <NUM> and the ground potential <NUM> as in the embodiment. Consequently, it is possible to reduce noise included in DC power supplied from the cell stack device <NUM>, and thus the PCS <NUM> can stably convert DC power into AC power.

The remaining parts in the cell stack device <NUM> illustrated in <FIG> will be described. The communication hole <NUM> and the communication hole <NUM> of the holding member <NUM> may be, for example, simple bolt holes through which bolts for fixing the cell <NUM> are inserted. The communication hole <NUM> may function as a gas supply manifold that supplies the reaction gas or the oxygen-containing gas to the plurality of cells <NUM>. The communication hole <NUM> may function as a gas discharge manifold that discharges the reaction gas or the oxygen-containing gas from the plurality of cells <NUM>. Hereinafter, a case where the communication hole <NUM> functions as an oxygen supply manifold that supplies oxygen-containing gas to the plurality of cells <NUM> and the communication hole <NUM> functions as an oxygen discharge manifold that discharges the oxygen-containing gas from the plurality of cells <NUM> as illustrated in <FIG> will be described.

The oxygen-containing gas flowing through the oxygen supply manifold is supplied from the communication hole <NUM> to the air chamber <NUM> via a flow path (not illustrated) formed in the air-electrode-side frame <NUM>. Furthermore, the oxygen-containing gas discharged from the air chamber <NUM> flows into the communication hole <NUM> via a flow path (not illustrated) formed in the air-electrode-side frame <NUM>.

A gas passage member <NUM> is located at an inlet of the communication hole <NUM>. The gas passage member <NUM> has a body <NUM> and a branch part <NUM>, and is interposed between the end current collection member <NUM> and the nut <NUM>.

A gas passage member <NUM> is located at an outlet of the communication hole <NUM>. The gas passage member <NUM> has a body <NUM> and a branch part <NUM>, and is interposed between the end current collection member <NUM> and the nut <NUM>.

Although not illustrated in <FIG>, the cell stack device <NUM> may have communication holes different from the communication hole <NUM> that supplies the oxygen-containing gas to the plurality of cells <NUM> and the communication hole <NUM> that discharges the oxygen-containing gas from the plurality of cells <NUM>. The cell stack device <NUM> may have, for example, a communication hole that functions as a fuel supply manifold that supplies fuel gas to the plurality of cells <NUM> or a fuel discharge manifold that discharges the fuel gas from the plurality of cells <NUM>. Furthermore, the cell stack device <NUM> may have communication holes that do not have the functions of supplying and discharging gas.

Moreover, the cell stack device <NUM> may have a communication hole through which the bolt <NUM> is not inserted, in addition to a communication hole through which the bolt <NUM> is inserted. The communication hole through which the bolt <NUM> is not inserted may function as a gas supply manifold or a gas discharge manifold.

Furthermore, in the aforementioned embodiment, the example in which the cell stacks 11A and 11B in the cell stack device <NUM> are connected in series has been described; however, the cell stacks 11A and 11B may be connected in parallel to form one battery.

Furthermore, in the aforementioned embodiment, the example in which the holding member <NUM> is grounded has been described; however, the holding member <NUM> does not necessarily have to be grounded. Even in such a case, by setting the potential of the positive electrode terminal 19A to be not more than that of the holding member <NUM>, the gap C is not easily formed between the fixing material <NUM> and the holding body <NUM>, which makes it possible to improve the durability of the cell stack device <NUM>.

As described above, the cell stack device <NUM> (<NUM>) according to the embodiment includes the cell stack <NUM> (<NUM>), the holding member <NUM> (<NUM>), and the positive electrode terminal 19A (<NUM>). The cell stack <NUM> (<NUM>) is constructed by stacking the plurality of cells <NUM> (<NUM>). The holding member <NUM> (<NUM>) holds the cells <NUM> (<NUM>). The positive electrode terminal 19A (<NUM>) functions as a positive electrode when power generated by the cell stack <NUM> (<NUM>) is output to the outside. Furthermore, the potential of the positive electrode terminal 19A (<NUM>) is not more than that of the holding member <NUM> (<NUM>). With this, it is possible to improve the durability of the cell stack device <NUM> (<NUM>).

Furthermore, in the cell stack device <NUM> (<NUM>) according to the embodiment, the positive electrode terminal 19A (<NUM>) and the holding member <NUM> (<NUM>) have the same potential. With this, it is possible to improve the durability of the cell stack device <NUM> (<NUM>).

Furthermore, in the cell stack device <NUM> (<NUM>) according to the embodiment, the potential of the positive electrode terminal 19A (<NUM>) is lower than that of the holding member <NUM> (<NUM>). With this, it is possible to improve the durability of the cell stack device <NUM> (<NUM>).

Furthermore, in the cell stack device <NUM> (<NUM>) according to the embodiment, the positive electrode terminal 19A (<NUM>) is connected to the ground potential <NUM>. In addition, in the cell stack device <NUM> (<NUM>) according to the embodiment, the noise reduction unit <NUM> that reduces noise is located between the positive electrode terminal 19A (<NUM>) and the ground potential <NUM>. With this, the PCS <NUM> can stably convert DC power into AC power.

Furthermore, the module <NUM> according to the embodiment is constructed by housing the cell stack device <NUM> (<NUM>) described above in the housing container <NUM>. With this, it is possible to acquire a module <NUM> having high durability.

Furthermore, the module housing device <NUM> according to the embodiment is constructed by housing, in an outer case, the module <NUM> described above and an auxiliary device for operating the module <NUM>. With this, it is possible to acquire a module housing device <NUM> having high durability.

Claim 1:
A fuel or electrolytic cell stack device (<NUM>, <NUM>) comprising:
a cell stack (<NUM>, 11A, 11B, <NUM>) constructed by stacking a plurality of cells (<NUM>, <NUM>);
a fixing member (<NUM>) comprising a fixing material (<NUM>) having oxide ion conductivity and a holding member (<NUM>, <NUM>), wherein the holding member (<NUM>, <NUM>) is configured to hold the cells (<NUM>, <NUM>), and wherein the fixing material (<NUM>) is configured to fix the cells (<NUM>) to the holding member (<NUM>); and
a positive electrode terminal (19A, <NUM>) configured to function as a positive electrode when power generated by the cell stack (<NUM>, 11A, 11B, <NUM>) is output to the outside,
characterized in that
a potential of the positive electrode terminal (19A, <NUM>) is not more than a potential of the holding member (<NUM>, <NUM>).