JP7799573B2 - Electrochemical cell device, module, and module housing device - Google Patents

Description

This disclosure relates to electrochemical cell devices, modules, and module housing devices.

In recent years, various fuel cell stack devices containing multiple fuel cell units have been proposed as next-generation energy sources. Fuel cell units are a type of electrochemical cell that can generate electricity using a fuel gas, such as a hydrogen-containing gas, and an oxygen-containing gas, such as air.

Japanese Patent Application Laid-Open No. 2021-180164 Japanese Patent Application Laid-Open No. 2015-220022

However, with conventional fuel cell stack devices, for example, there may be variations in temperature during power generation, and there is room for improvement in durability.

One aspect of this embodiment aims to provide highly durable electrochemical cell devices, modules, and module housing devices.

An electrochemical cell device according to one aspect of the embodiment includes a cell stack and a conductive member. The cell stack has a plurality of element units aligned in a first direction. The conductive members are respectively positioned between the plurality of element units. The cell stack has a first region located in the center in the first direction and a second region located at an end in the first direction. The conductive member located in the first region has a first portion and a second portion having a lower resistivity than the first portion. The conductive member located in the second region has a higher resistivity than the second portion.

An electrochemical cell device according to one aspect of the embodiment includes a cell stack and a conductive member. The cell stack has a plurality of element units aligned in a first direction. The conductive members are respectively positioned between the plurality of element units. The cell stack has a first region located in the center in the first direction and a second region located at an end in the first direction. The conductive member located in the first region includes a first member and a second member having a lower resistivity than the first member. The conductive member located in the second region has a higher resistivity than the second member.

The module of the present disclosure also includes the electrochemical cell device described above and a storage container for storing the electrochemical cell device.

The module housing device of the present disclosure also includes the module described above, auxiliary equipment for operating the module, and an exterior case that houses the module and the auxiliary equipment.

According to one aspect of the embodiment, highly durable electrochemical cell devices, modules, and module housing devices can be provided.

FIG. 1A is a cross-sectional view showing an example of an electrochemical cell according to a first embodiment. FIG. 1B is a side view of an example of the electrochemical cell according to the first embodiment, viewed from the air electrode side. FIG. 1C is a side view of an example of the electrochemical cell according to the first embodiment, viewed from the interconnector side. FIG. 2A is a perspective view showing an example of an electrochemical cell device according to the first embodiment. FIG. 2B is a cross-sectional view taken along line XX shown in FIG. 2A. FIG. 2C is a top view illustrating an example of the electrochemical cell device according to the first embodiment. FIG. 3 is a cross-sectional view showing an example of the temperature distribution in the electrochemical cell device. FIG. 4 is an enlarged cross-sectional view of the electrochemical cell device according to the first embodiment. FIG. 5 is a cross-sectional view showing an example of the conductive member according to the first embodiment. FIG. 6 is a cross-sectional view taken along line AA shown in FIG. FIG. 7A is a cross-sectional view illustrating an example of the conductive member according to the first embodiment. FIG. 7B is a cross-sectional view showing another example of the conductive member according to the first embodiment. FIG. 7C is a cross-sectional view showing another example of the conductive member according to the first embodiment. FIG. 7D is a cross-sectional view showing another example of the conductive member according to the first embodiment. FIG. 8 is an external perspective view illustrating an example of a module according to the first embodiment. FIG. 9 is an exploded perspective view schematically illustrating an example of a module housing device according to the first embodiment. FIG. 10 is a cross-sectional view showing another example of the electrochemical cell device according to the first embodiment. FIG. 11 is a perspective view showing an example of an electrochemical cell device according to the second embodiment. FIG. 12 is a cross-sectional view showing an example of the temperature distribution in a flat-plate electrochemical cell device. FIG. 13 is a cross-sectional view showing an example of an electrochemical cell device according to the second embodiment. FIG. 14 is a cross-sectional view showing an example of the first region R1 shown in FIG. FIG. 15 is a cross-sectional view showing another example of the electrochemical cell device according to the second embodiment. FIG. 16A is a cross-sectional view showing an example of an electrochemical cell constituting the electrochemical cell device according to the third embodiment. FIG. 16B is a cross-sectional view showing another example of the electrochemical cell according to the third embodiment. FIG. 16C is a cross-sectional view showing another example of the electrochemical cell according to the third embodiment.

Embodiments of the electrochemical cell device, module, and module housing device disclosed herein are described in detail below with reference to the accompanying drawings. Note that this disclosure is not limited to the embodiments described below.

It should also be noted that the drawings are schematic, and the dimensional relationships and proportions of each element may differ from reality. Furthermore, there may be parts in the drawings where the dimensional relationships and proportions differ.

[First embodiment]
<Electrochemical cell>
1A to 1C, an electrochemical cell constituting an electrochemical cell device according to a first embodiment will be described using an example of a solid oxide fuel cell. The electrochemical cell device may include a cell stack having a plurality of electrochemical cells. An electrochemical cell device having a plurality of electrochemical cells will be simply referred to as a cell stack device.

Figure 1A is a cross-sectional view showing an example of an electrochemical cell according to an embodiment, Figure 1B is a side view of an example of an electrochemical cell according to an embodiment as seen from the air electrode side, and Figure 1C is a side view of an example of an electrochemical cell according to an embodiment as seen from the interconnector side. Note that Figures 1A to 1C show enlarged views of portions of each component of the electrochemical cell. Hereinafter, the electrochemical cell may also be simply referred to as a cell.

In the example shown in Figures 1A to 1C, cell 1 is a hollow, flat, elongated plate. As shown in Figure 1B, the shape of the entire cell 1 when viewed from the side is, for example, a rectangle with a side length in the length direction L of 5 cm to 50 cm and a width direction W perpendicular to this length direction L of 1 cm to 10 cm. The overall thickness of this cell 1 in the thickness direction T is, for example, 1 mm to 5 mm.

As shown in Figure 1A, cell 1 comprises a conductive support substrate 2, an element section 3, and an interconnector 4. Support substrate 2 is columnar, having a pair of opposing flat surfaces n1, n2 and a pair of arc-shaped side surfaces m connecting the flat surfaces n1, n2.

The element section 3 is provided on the flat surface n1 of the support substrate 2. The element section 3 includes a fuel electrode layer 5, a solid electrolyte layer 6, and an air electrode layer 8. In the example shown in FIG. 1A, the interconnector 4 is located on the flat surface n2 of the cell 1. The cell 1 may also include an intermediate layer 7 between the solid electrolyte layer 6 and the air electrode layer 8.

Also, as shown in FIG. 1B, the air electrode layer 8 does not extend to the lower end of the cell 1. At the lower end of the cell 1, only the solid electrolyte layer 6 is exposed on the surface of the flat surface n1. Also, as shown in FIG. 1C, the interconnector 4 may extend to the lower end of the cell 1. At the lower end of the cell 1, the interconnector 4 and the solid electrolyte layer 6 are exposed on the surface. Note that, as shown in FIG. 1A, the solid electrolyte layer 6 is exposed on the surface of a pair of arcuate side surfaces m of the cell 1. The interconnector 4 does not have to extend to the lower end of the cell 1.

The following describes each component that makes up Cell 1.

The support substrate 2 has gas flow channels 2a therein through which gas flows. The example of the support substrate 2 shown in Figure 1A has six gas flow channels 2a. The support substrate 2 is gas permeable, allowing the fuel gas flowing through the gas flow channels 2a to permeate to the fuel electrode layer 5. The support substrate 2 may be conductive. The conductive support substrate 2 collects electricity generated in the element section 3 to the interconnector 4.

The material of the support substrate 2 includes, for example, an iron-group metal component and an inorganic oxide. The iron-group metal component may be, for example, Ni (nickel) and/or NiO. The inorganic oxide may be, for example, a specific rare earth element oxide. The rare earth element oxide may include, for example, one or more rare earth elements selected from Sc, Y, La, Nd, Sm, Gd, Dy, and Yb.

A commonly known material can be used for the fuel electrode layer 5. The fuel electrode layer 5 may be made of porous conductive ceramics, such as ceramics containing calcium oxide, magnesium oxide, or _ZrO2 solid-solubilized with a rare earth element oxide, and Ni and/or NiO. The rare earth element oxide may contain, for example, a plurality of rare earth elements selected from Sc, Y, La, Nd, Sm, Gd, Dy, and Yb. Calcium oxide, magnesium oxide, or _ZrO2 solid-solubilized with a rare earth element oxide is sometimes referred to as stabilized zirconia. Stabilized zirconia also includes partially stabilized zirconia.

The solid electrolyte layer 6 is an electrolyte that transfers ions between the fuel electrode layer 5 and the air electrode layer 8. At the same time, the solid electrolyte layer 6 has gas barrier properties, making it less likely for fuel gas and oxygen-containing gas to leak.

The material of the solid electrolyte layer 6 may be, for example, _ZrO2 in which 3 mol % to 15 mol % of a rare earth element oxide, calcium oxide, or magnesium oxide is solid-solved. The rare earth element oxide may include, for example, one or more rare earth elements selected from Sc, Y, La, Nd, Sm, Gd, Dy, and Yb. The solid electrolyte layer 6 may include, for example, _CeO2 in which La, Nd, Sm, Gd, or Yb is solid-solved, _BaZrO3 in which Sc or Yb is solid-solved, or _BaCeO3 in which Sc or Yb is solid-solved.

The air electrode layer 8 is gas permeable. The open porosity of the air electrode layer 8 may be, for example, in the range of 20% to 50%, particularly 30% to 50%.

There are no particular restrictions on the material of the air electrode layer 8 as long as it is one that is generally used for air electrodes. The material of the air electrode layer 8 may be, for example, a conductive ceramic such as a so-called ABO ₃ type perovskite oxide.

The material of the air electrode layer 8 may be, for example, a composite oxide in which Sr (strontium) and La (lanthanum) coexist at the A site. Examples of _such composite oxides include _{LaxSr1 -xCoyFe1 -} yO3, LaxSr1 _{-xMnO3 , LaxSr1 - xFeO3} , and _{LaxSr1 - xCoO3} , where _x is 0<x<1 and y is 0<y< ₁ .

Furthermore, when the element section 3 has an intermediate layer 7, the intermediate layer 7 functions as a diffusion suppression layer. When elements such as Sr (strontium) contained in the air electrode layer 8 diffuse into the solid electrolyte layer 6, a resistive layer such as _SrZrO3 is formed in the solid electrolyte layer 6. The intermediate layer 7 makes it difficult for Sr to diffuse, thereby making it difficult for _SrZrO3 and other electrically insulating oxides to form.

There are no particular restrictions on the material of intermediate layer 7, as long as it is a material generally used as an element diffusion suppression layer between air cathode layer 8 and solid electrolyte layer 6. The material of intermediate layer 7 may include, for example, cerium oxide (CeO ₂ ) in which a rare earth element other than Ce (cerium) is dissolved. Examples of such rare earth elements that may be used include Gd (gadolinium) and Sm (samarium).

Furthermore, the interconnector 4 is dense, making it less likely for the fuel gas flowing through the gas flow passage 2a located inside the support substrate 2 and the oxygen-containing gas flowing outside the support substrate 2 to leak. The interconnector 4 may have a relative density of 93% or more, particularly 95% or more.

The material for the interconnector 4 may be a lanthanum chromite-based perovskite oxide ( _LaCrO3 -based oxide), a lanthanum strontium titanium-based perovskite oxide (LaSrTiO3 _- based oxide), or the like. These materials are conductive and are resistant to reduction and oxidation even when in contact with a fuel gas such as a hydrogen-containing gas and an oxygen-containing gas such as air. Alternatively, a metal or an alloy may be used as the material for the interconnector 4.

<Electrochemical cell device>
Next, an electrochemical cell device according to this embodiment using the above-described cell 1 will be described with reference to Figures 2A to 2C. Figure 2A is a perspective view showing an example of the electrochemical cell device according to the first embodiment, Figure 2B is a cross-sectional view taken along line X-X shown in Figure 2A, and Figure 2C is a top view showing an example of the electrochemical cell device according to the first embodiment.

As shown in Figure 2A, the cell stack device 10 includes a cell stack 11 having multiple cells 1 arranged (stacked) in the thickness direction T of the cells 1 (see Figure 1A), and fixing members 12, 12a.

The fixing member 12 has a fixing material 13 and a support member 14. The support member 14 supports the cell 1. The fixing material 13 fixes the cell 1 to the support member 14. The support member 14 also has a support 15 and a gas tank 16. The support 15 and gas tank 16, which are the support member 14, are made of, for example, metal and are electrically conductive.

As shown in Figure 2B, the support body 15 has insertion holes 15a into which the lower ends of the multiple cells 1 are inserted. The lower ends of the multiple cells 1 and the inner wall of the insertion holes 15a are joined with fixing material 13.

The gas tank 16 has an opening for supplying reaction gas to the multiple cells 1 through the insertion holes 15a, and a groove 16a located around the opening. The outer edge of the support 15 is joined to the gas tank 16 by a bonding material 21 filled in the groove 16a of the gas tank 16.

In the example shown in Figure 2A, fuel gas is stored in an internal space 22 formed by the support body 15, which is the support member 14, and the gas tank 16. A gas distribution pipe 20 is connected to the gas tank 16. The fuel gas is supplied to the gas tank 16 through this gas distribution pipe 20, and is then supplied from the gas tank 16 to the gas flow path 2a (see Figure 1A) inside the cell 1. The fuel gas supplied to the gas tank 16 is generated in a reformer 102 (see Figure 7), which will be described later.

Hydrogen-rich fuel gas can be produced by steam reforming the raw fuel. When fuel gas is produced by steam reforming, the fuel gas contains water vapor.

The example shown in Figure 2A includes two rows of cell stacks 11, a support member 14, two supports 15, and a gas tank 16. Each of the two rows of cell stacks 11 has a plurality of cells 1. Each cell stack 11 is fixed to a respective support 15. The gas tank 16 has two through-holes on its top surface. A support 15 is disposed in each through-hole. The internal space 22 is formed by the one gas tank 16 and the two supports 15. Figure 2A shows a cell stack device 10 having two rows of cell stacks 11, but the electrochemical cell device may have one row of cell stacks 11, or three or more rows of cell stacks 11.

The shape of the insertion hole 15a is, for example, an oval shape when viewed from above. For example, the length of the insertion hole 15a in the arrangement direction of the cells 1, i.e., the thickness direction T, is greater than the distance between the two end current collecting members 17 located at both ends of the cell stack 11. For example, the width of the insertion hole 15a is greater than the length of the cell 1 in the width direction W (see Figure 1A).

As shown in Figure 2B, the joint between the inner wall of the insertion hole 15a and the lower end of the cell 1 is filled with a fixing material 13 and solidified. This bonds and fixes the inner wall of the insertion hole 15a to the lower end of each of the multiple cells 1, and also bonds and fixes the lower ends of the cells 1 to each other. The gas flow path 2a of each cell 1 communicates with the internal space 22 of the support member 14 at its lower end.

The fixing material 13 and the bonding material 21 can be made of a material with low conductivity, such as glass. Specific materials for the fixing material 13 and the bonding material 21 include amorphous glass, and in particular, crystallized glass.

As the crystallized glass, for example, any of SiO ₂ —CaO-based, MgO—B ₂ O _3- based, La ₂ O ₃ —B ₂ O ₃ —MgO-based, La ₂ O ₃ —B ₂ O ₃ —ZnO-based, SiO ₂ —CaO—ZnO-based materials may be used, and in particular, SiO ₂ —MgO-based materials may be used.

As shown in FIG. 2B , a conductive member 18 is interposed between adjacent cells 1 among the plurality of cells 1. The conductive member 18 electrically connects the fuel electrode layer 5 of one adjacent cell 1 to the air electrode layer 8 of the other cell 1 in series. More specifically, the conductive member 18 connects the interconnector 4 electrically connected to the fuel electrode layer 5 of one adjacent cell 1 to the air electrode layer 8 of the other cell 1. If the interconnector 4 is made of a metal or alloy, the interconnector 4 and the conductive member 18 may be integrated, or the conductive member 18 may also serve as the interconnector 4. Details of the conductive member 18 will be described later.

As shown in Figure 2B, an end current collecting member 17 is electrically connected to the cell 1 located at the outermost position in the arrangement direction of the multiple cells 1. The end current collecting member 17 is connected to a conductive portion 19 that protrudes outside the cell stack 11. The conductive portion 19 collects electricity generated by the cells 1 and extracts it to the outside. Note that the end current collecting member 17 is not shown in Figure 2A.

Also, as shown in Figure 2C, the cell stack device 10 has two cell stacks 11A and 11B connected in series, functioning as a single battery. Therefore, the conductive parts 19 of the cell stack device 10 are divided into a positive terminal 19A, a negative terminal 19B, and a connection terminal 19C.

The positive terminal 19A is the positive electrode when the power generated by the cell stack 11 is output to the outside, and is electrically connected to the positive side end current collector 17 of the cell stack 11A. The negative terminal 19B is the negative electrode when the power generated by the cell stack 11 is output to the outside, and is electrically connected to the negative side end current collector 17 of the cell stack 11B.

Connection terminal 19C electrically connects the negative electrode side end current collecting member 17 in cell stack 11A to the positive electrode side end current collecting member 17 in cell stack 11B.

<Temperature distribution during power generation>
Next, the temperature distribution during power generation in the electrochemical cell device will be described with reference to FIG. 3 . FIG. 3 is a cross-sectional view showing an example of the temperature distribution in the electrochemical cell device. The cell stack device 10X shown in FIG. 3 corresponds to an enlarged view of a portion of the cell stack 11 included in the cell stack device 10 shown in FIG. 2B . Note that FIG. 3 shows simplified illustrations of, for example, the cells 1, conductive members 18, etc. Also, in other drawings described below, simplified illustrations of components may be used. For ease of explanation, the number of cells 1 included in the cell stack device is shown as eight in FIG. 3 and FIG. 4 described below.

As shown in FIG. 3, a conductive member 18 extending in the longitudinal direction is located between adjacent cells 1 in the thickness direction T of the cells 1, electrically connecting the adjacent cells 1. During power generation, temperatures t1 to t6 of the cell stack device 10X are in the order of t1 > t2 > t3 > t4 > t5 > t6, with the temperature at the center of the cell 1 in the thickness direction T (first direction) and at the upper end in the length direction L away from the fixing material 13 being the highest. Furthermore, the temperature during power generation decreases toward the ends in the thickness direction T and the lower end in the length direction L away from these areas. Therefore, the first region R1 located in the center of the cell 1 in the thickness direction T (first direction) is hotter than the second region R2 located at both ends of the cell 1 in the thickness direction T (first direction), for example, which tends to reduce durability.

In this embodiment, therefore, a conductive member 18 with different resistivities is applied between the first region R1 and the second region R2. Figure 4 is an enlarged cross-sectional view of the electrochemical cell device according to the first embodiment.

As shown in FIG. 4, the conductive member 18 located in the first region R1 has a first portion 181 and a second portion 182 that has a lower resistivity than the first portion 181. As a result, the resistivity of the conductive member 18 located in the first portion 181, which is prone to high temperatures, is made higher than that of the other portions, thereby reducing the amount of current flowing through it, and the conductive member 18 located in the other portion, the second portion 182, has a lower resistivity, thereby increasing the amount of current flowing through it. This reduces temperature variations during power generation and increases the durability of the electrochemical cell device.

In addition, the conductive member 183 located in the second region R2 has a higher resistivity than the second portion 182. As a result, in the second region R2, which is less likely to become hot, the resistance heating of the conductive member 183 actively promotes temperature rise. This reduces temperature variation during power generation and improves battery performance.

The conductive member 183 as a whole only needs to have a higher resistivity than the second portion 182. The conductive member 183 may have a higher resistivity than the first portion 181, or may have the same or lower resistivity as the first portion. The conductive member 183 may have a high resistance portion and a low resistance portion. When the conductive member 183 has a high resistance portion and a low resistance portion, the difference in resistivity between the high resistance portion and the low resistance portion is smaller than the difference in resistivity between the first portion 181 and the second portion 182. The low resistance portion of the conductive member 183 may have the same resistivity as the second portion 182 or a lower resistivity than the second portion 182. The conductive member 183 does not need to have a low resistance portion.

Here, an example of a specific configuration of the conductive member 18 will be described using Figures 5 and 6. Figure 5 is a cross-sectional view showing an example of a conductive member according to the first embodiment.

As shown in FIG. 5, the conductive member 18 has a connection portion 18a that connects to cell 1A, one of the adjacent cells 1, and a connection portion 18b that connects to cell 1B, the other cell 1. The conductive member 18 also has connecting portions 18c at both ends in the width direction W, which connect the connecting portions 18a and 18b. This allows the conductive member 18 to electrically connect adjacent cells 1 in the thickness direction T.

In addition, connection portions 18a and 18b have contact portions 18a1 and 18b1 that contact cells 1A and 1B, and non-contact portions 18a2 and 18b2 that do not contact cells 1A and 1B.

Figure 6 is a cross-sectional view taken along line A-A in Figure 5. The conductive member 18 extends in the longitudinal direction L of the cell 1. The conductive member 18 has a comb-like shape in cross section, with connecting portions 18a and 18b extending alternately from the connecting portion 18c toward cells 1A and 1B.

Next, specific examples of conductive members 18 having a first portion 181 and a second portion 182 will be described using Figures 7A to 7D. Figure 7A is a cross-sectional view showing an example of a conductive member according to the first embodiment.

As shown in FIG. 7A, the conductive member 18 has a substrate 180 and a coating 30 covering the substrate 180. The substrate 180 is electrically conductive and heat resistant. The substrate 180 contains chromium. The substrate 180 is, for example, stainless steel. The substrate 180 may also contain, for example, a metal oxide.

The coating 30 has insulating or low insulating properties. The coating 30 contains, for example, chromium oxide (Cr ₂ O ₃ ), aluminum oxide (Al ₂ O ₃ ), or a composite oxide containing Al and/or Si. The conductive member 18 shown in FIG. 7A has a first portion 181 and a second portion 182 that have different resistivities due to the difference in thickness of the coating 30. That is, the resistivity of the first portion 181, where the coating 30 is thicker than the second portion 182, is higher than the resistivity of the second portion 182.

Figures 7B to 7D are cross-sectional views showing another example of a conductive member according to the first embodiment.

As shown in Figure 7B, the conductive member 18 differs from the conductive member 18 shown in Figure 7A in that it has a coating 31 covering the substrate 180 instead of the coating 30.

The coating 31 is conductive. The coating 31 contains, for example, a conductive metal material and/or metal oxide. The conductive member 18 shown in FIG. 7B has a first portion 181 and a second portion 182 with different resistivities due to the difference in thickness of the coating 31. That is, the resistivity of the second portion 182, where the coating 31 is thicker than the first portion 181, is lower than the resistivity of the first portion 181. The conductive metal oxide contained in the coating 31 may be, for example, a composite oxide having a spinel structure, such as Zn(Co _x Mn _1-x ) ₂ O ₄ (0<x<1) such as ZnMnCoO ₄ , Mn _1.5 Co _1.5 O ₄ , MnCo ₂ O ₄ , or CoMn ₂ O ₄ . The conductive metal oxide may also be a so-called ABO _3- type perovskite oxide.

The conductive member 18 may have both a coating 30 and a coating 31 that has higher conductivity than the coating 30. For example, the conductive member 18 may have a coating 30 that covers the substrate 180, and a coating 31 that further covers the coating 30. In this case, the thickness of the coating 30 in the second portion 182 may be smaller and/or the thickness of the coating 31 in the second portion 182 may be greater than that in the first portion 181.

Furthermore, the conductive member 18 shown in Figure 7C differs from the conductive member 18 shown in Figure 7A in that it has coatings 32 and 33 covering the substrate 180 instead of the coating 30.

The coatings 32 and 33 are conductive or insulating. The coating 32 is more insulating than the coating 33. Alternatively, the coating 33 is more conductive than the coating 32.

The conductive member 18 shown in FIG. 7C has a first portion 181 and a second portion 182 with different resistivities due to the coatings 32, 33 being made of different materials. That is, the resistivity of the second portion 182, which has a coating 33 that is less insulating or more conductive than the coating 32, is lower than the resistivity of the first portion 181. The coatings 32, 33 may be made of the same material but with different porosities. If the porosity of the coating 32 is higher than that of the coating 33, the coating 32 will have higher insulating properties or lower conductivity than the coating 33. The materials of the coatings 32, 33 may be the same as those contained in the coatings 30, 31.

The conductive member 18 shown in Figure 7D has regions 180a and 180b in which the material of the substrate 180 is different from each other. Region 180b has higher conductivity than region 180a. As a result, the resistivity of the second region 182 is lower than the resistivity of the first region 181.

As such, the conductive member 18 according to this embodiment may be produced by any method. The coatings 30 and 31 shown in Figures 7A and 7B may be formed, for example, by changing the number of applications and/or the concentration of the dipping liquid in a dipping method, or by changing the film-forming electrode in an electrodeposition or plating method. The coatings 32 and 33 shown in Figure 7C may be formed, for example, by changing the type of dipping liquid in a dipping method. The conductive member 18 shown in Figure 7D may be formed, for example, by welding or joining.

<Module>
Next, a module according to this embodiment using the above-described cell stack device 10 will be described with reference to Fig. 8. Fig. 8 is an external perspective view showing the module according to the first embodiment. Fig. 8 shows a state in which the front and rear surfaces, which are part of the storage container 101, have been removed and the cell stack device 10 of the fuel cell stored inside has been pulled out to the rear.

As shown in Figure 8, the module 100 is constructed by housing a cell stack device 10 inside a storage container 101. Also, above the cell stack device 10, a reformer 102 is located to generate fuel gas to be supplied to the cells 1.

The reformer 102 generates fuel gas by reforming raw fuel such as natural gas or kerosene supplied through the raw fuel supply pipe 103. The reformer 102 is preferably designed to be capable of steam reforming, an efficient reforming reaction. The reformer 102 is capable of steam reforming by including a vaporization section 102a for vaporizing water and a reforming section 102b in which a reforming catalyst (not shown) is disposed for reforming the raw fuel into fuel gas.

The fuel gas produced in the reformer 102 is supplied to the fixed member 12 through the gas flow pipe 20, and then from the fixed member 12 to the gas flow path 2a (see Figure 1A) provided inside the cell 1.

Furthermore, in a module 100 configured as described above, during normal power generation, the temperature inside the module 100 reaches approximately 500°C to 1000°C due to the combustion and power generation by cell 1.

As described above, such a module 100 is configured to house a highly durable cell stack device 10, thereby making it a highly durable module 100.

<Module housing device>
Fig. 9 is an exploded perspective view showing an example of a module housing device according to the first embodiment. The module housing device 110 includes an outer case 111, the module 100 shown in Fig. 8, and auxiliary equipment (not shown). The auxiliary equipment operates the module 100. The module 100 and the auxiliary equipment are housed in the outer case 111. Note that Fig. 9 omits some components.

The outer case 111 of the module accommodating device 110 shown in Figure 9 has support posts 112 and an outer panel 113. A partition panel 114 divides the interior of the outer case 111 into upper and lower sections. The space above the partition panel 114 in the outer case 111 is a module accommodating chamber 115 that accommodates the module 100, and the space below the partition panel 114 in the outer case 111 is an auxiliary equipment accommodating chamber 116 that accommodates the auxiliary equipment that operates the module 100. Note that in Figure 8, the auxiliary equipment accommodated in the auxiliary equipment accommodating chamber 116 is omitted.

The partition plate 114 also has an air flow port 117 for allowing air from the auxiliary equipment housing chamber 116 to flow toward the module housing chamber 115. The exterior plate 113 that constitutes the module housing chamber 115 has an exhaust port 118 for exhausting air from within the module housing chamber 115.

In such a module storage device 110, as described above, highly durable modules 100 are provided in the module storage chamber 115, thereby making the module storage device 110 highly durable.

Figure 10 is a cross-sectional view showing another example of an electrochemical cell device according to the first embodiment. The cell stack device 10 shown in Figure 10 differs from the conductive member 18 according to the above-described embodiment in that it has a first member 18A and a second member 18B with different resistivities as the conductive member 18. The resistivity of the second member 18B is configured to be lower than that of the first member 18A, and the first member 18A and the second member 18B are respectively disposed between adjacent cells 1. In this way, even when the first member 18A and the second member 18B with different resistivities are used as the conductive member 18, temperature variation in the first region R1 (see Figure 4) is reduced. Therefore, this modification improves the durability of the cell stack device 10.

The first member 18A and the second member 18B can be manufactured, for example, in accordance with the first portion 181 and the second portion 182 shown in Figures 7A to 7D, respectively. Furthermore, the first member 18A and the second member 18B may be in contact with each other or spaced apart. Spaced apart, the current flowing through the first member 18A can be more reliably reduced, thereby increasing the durability of the cell stack device 10.

Second Embodiment
FIG. 11 is a perspective view showing an example of an electrochemical cell device according to a second embodiment. The cell stack device 10A shown in FIG. 11 is an electrochemical cell device in which flat electrochemical cells, each having an element unit 3A and a conductive member 18 sandwiching the element unit 3A, are stacked. The element unit 3A has a solid electrolyte layer (e.g., solid electrolyte layer 6) and a first electrode layer (e.g., fuel electrode layer 5) and a second electrode layer (e.g., air electrode layer 8) sandwiching the solid electrolyte layer. The conductive member 18 has a flow path (not shown) through which reactant gas flows, and the flow path is sealed with a sealing member (not shown). End current collecting members 91 and 92 are located at both ends of the cell stack device 10A.

Figure 12 is a cross-sectional view showing an example of temperature distribution in a flat-plate electrochemical cell. As shown in Figure 12, during power generation, temperatures t11 to t15 in the cell stack device 10Y are highest in the center of the cell stack device 10Y, in the order t11 > t12 > t13 > t14 > t15. Furthermore, the temperature during power generation decreases toward both ends in the Y-axis and Z-axis directions, away from the center. Therefore, the first region R1 located in the center of the element unit 3A in the thickness direction (Z-axis direction) becomes hotter than the second region R2 located at both ends in the thickness direction (Z-axis direction) of the element unit 3A, for example, which makes it more likely for durability to decrease. While Figure 12 shows a cross-section along the YZ plane, the same can be said for a cross-section along the ZX plane as in Figure 12.

In this embodiment, therefore, a conductive member 18 with different resistivities is applied between the first region R1 and the second region R2. Figure 13 is a cross-sectional view showing an example of an electrochemical cell device according to the second embodiment.

As shown in FIG. 13, the conductive member 18 located in the first region R1 has a first portion 181 and a second portion 182 that has a lower resistivity than the first portion 181. As a result, the resistivity of the conductive member 18 located in the first portion 181, which is prone to high temperatures, is made higher than that of the other portions, thereby reducing the amount of current flowing through it, and the conductive member 18 located in the other portion, the second portion 182, has a lower resistivity, thereby increasing the amount of current flowing through it. This reduces temperature variations during power generation and increases the durability of the electrochemical cell device.

In addition, the conductive member 183 located in the second region R2 has a higher resistivity than the second portion 182. As a result, in the second region R2, which is less likely to become hot, the resistance heating of the conductive member 183 actively promotes temperature rise. This reduces temperature variation during power generation and improves battery performance.

Figure 14 is a cross-sectional view showing an example of the first region R1 shown in Figure 13. The conductive members 18 located in the first region R1 of the cell stack device 10A are electrically connected via conductive member 18-3, which is an interconnector, with conductive member 18-1 connected to one adjacent element unit 3A and conductive member 18-2 connected to the other adjacent element unit 3A. Hereinafter, conductive members 18-1 to 18-3 located between element units 3A may be collectively referred to as conductive members 18.

As mentioned above, the temperature near the center of the cell stack device 10A, which becomes hot during power generation, is difficult to reduce, which can result in variations in temperature within the cell stack device 10A. Specifically, the temperature in the center of the cell stack device 10A rises more than on the outer edges away from the center of the cell stack device 10A, and for example, the temperature becomes higher than that suitable for power generation, which can easily reduce durability.

As shown in FIG. 14, temperature variation may be reduced by applying a conductive member 18 having a first portion 181 and a second portion 182 between element units 3A located in the first region R1 of the cell stack device 10A. Specifically, the conductive member 18 is positioned so that the first portion 181 is connected to the central portion between the element units 3A in the X-axis direction and/or Y-axis direction, and the second portion 182 is connected to a portion away from the central portion between the element units 3A in the X-axis direction and/or Y-axis direction. The resistivity of the first portion 181 is greater than the resistivity of the second portion 182.

As a result, the amount of current flowing through the first portion 181 is less than that through the second portion 182, reducing the temperature rise in the first portion 181. Therefore, according to this embodiment, the durability of the cell stack device 10A is increased.

In the above description, conductive members 18-1 to 18-3 are collectively referred to as conductive member 18. However, conductive member 18-3, which is different from conductive members 18-1 and 18-2, may be used as a third member, and conductive members 18-1 and 18-2 may be connected in series.

Figure 15 is a cross-sectional view showing another example of an electrochemical cell device according to the second embodiment. The cell stack device 10B shown in Figure 15 differs from the conductive member 18 shown in Figure 14 in that it has a first member 18A and a second member 18B with different resistivities as the conductive member 18 located in the first region R1. The resistivity of the second member 18B is lower than that of the first member 18A, and the first member 18A and the second member 18B are respectively disposed between adjacent element units 3A. In this way, even when the first member 18A and the second member 18B with different resistivities are used as the conductive member 18, the temperature rise in the central portion of the cell stack device 10B is reduced. Therefore, this modification improves the durability of the cell stack device 10B.

Furthermore, the conductive member 183 located in the second region R2 (see FIG. 13) has a higher resistivity than the second portion 182 or the second member 18B. This actively promotes temperature rise in the second region R2, where temperatures are less likely to become high, through resistance heating of the conductive member 183. This reduces temperature variation during power generation and improves battery performance. Note that, like the conductive member 18 located in the first region R1, the conductive member 18-1 connected to one adjacent element portion 3A and the conductive member 18-2 connected to the other adjacent element portion 3A may also be electrically connected via the conductive member 18-3, which is an interconnector, in the conductive member 18 located in the second region R2.

[Third embodiment]
Fig. 16A is a cross-sectional view showing an example of an electrochemical cell constituting an electrochemical cell device according to the third embodiment. Figs. 16B and 16C are cross-sectional views showing another example of an electrochemical cell according to the third embodiment. In this embodiment, a cell stack device 10C is formed by applying the cell 1 shown in Figs. 16A to 16C to the cell stack device 10 shown in Fig. 2A or 11.

As shown in Figures 16A to 16C, the cell 1 includes an element portion 3C, which is composed of a stack of an anode layer 5, a solid electrolyte layer 6, an intermediate layer 7, and an air cathode layer 8, and a support substrate 2. The support substrate 2 has through-holes or pores at the portion of the element portion 3C that contacts the anode layer 5, and includes a member 120 located outside the gas flow path 2a. The support substrate 2 allows gas to flow between the gas flow path 2a and the element portion 3C. The support substrate 2 may include, for example, one or more metal members. The material of the metal member may be an alloy containing chromium. The metal member may have a conductive coating layer. The support substrate 2 is a conductive member that electrically connects adjacent cells 1. The element portion 3C may be formed directly on the support substrate 2, or may be bonded to the support substrate 2 with a bonding material.

In the example shown in Figure 16A, the side surfaces of the fuel electrode layer 5 are covered with a solid electrolyte layer 6, airtightly sealing the gas flow path 2a through which the fuel gas flows. As shown in Figure 16B, the side surfaces of the fuel electrode layer 5 may be covered and sealed with a dense sealing material 9. The sealing material 9 covering the side surfaces of the fuel electrode layer 5 may be electrically insulating. The material of the sealing material 9 may be, for example, glass or ceramics.

Furthermore, the gas flow path 2a of the support substrate 2 may be formed by a member 120 having projections and recesses, as shown in Figure 16C.

In this embodiment, the member 120 is joined to the air electrode layer 8 of another adjacent cell 1 via other conductive members such as inter-cell connecting members and bonding materials. Note that the member 120 may also be in direct contact with the air electrode layer 8 of another cell 1 without the intermediary of other conductive members, etc.

In this embodiment, a cell 1 including a support substrate 2 (conductive member 18) having a first portion 181 and a second portion 182 is arranged in the first region R1 of the cell stack device 10C. Specifically, the first portion 181 of the support substrate 2 (conductive member 18) is positioned in the portion 1a of the cell 1 that is relatively hot, and the second portion 182 is positioned in the portion 1b of the cell 1 that is relatively cold. Because the resistivity of the first portion 181 is higher than that of the second portion 182, the amount of current flowing through the first portion 181 is lower than that of the second portion 182, thereby reducing the temperature rise in portion 1a. Therefore, this embodiment improves the durability of the support substrate 2 (conductive member 18) and the cell stack device 10. Note that in Figures 16A to 16C, the portion 1a of the cell 1 that is hot is shown as being near the center of the element portion 3B, as in the second embodiment. However, as in the first embodiment, the portion 1a of the cell 1 that is hot may be near the fuel gas outlet.

Note that the first region R1 and the second region R2 are not limited to the examples shown in Figures 3, 4, 12, and 13. The first region R1 and the second region R2 can be set as appropriate depending on the structure, characteristics, etc. of the cell stack. For example, one conductive member 18 sandwiched between two cells 1 located adjacent to the first region R1 at the center of the cell stack may have a first portion and a second portion, and one conductive member 18 located in the second region R2 at one end of the cell stack may have a higher resistivity than the second portion 182.

In addition, the arrangement and ratio of the first portion 181 and second portion 182 of the conductive member 18 located in the first region R1 can be set appropriately depending on the structure of the cell 1 located in the first region R1.

<Other Modifications>
In the above-described embodiments, a fuel cell, a fuel cell stack device, a fuel cell module, and a fuel cell device are shown as examples of a "battery chemical cell," a "battery chemical cell device," a "module," and a "module housing device." However, other examples may be an electrolytic cell, an electrolytic cell stack device, an electrolytic module, and an electrolytic device, respectively. The electrolytic cell has a hydrogen electrode and an oxygen electrode, and decomposes water vapor into hydrogen and oxygen when supplied with electric power. Furthermore, in the above-described embodiments, an oxide ion conductor or a hydrogen ion conductor is shown as an example of the electrolyte material of the electrochemical cell, but a hydroxide ion conductor may also be used.

The present disclosure has been described in detail above, but the present disclosure is not limited to the above-described embodiments, and various modifications and improvements are possible without departing from the spirit and scope of the present disclosure.

As described above, an electrochemical cell device (e.g., cell stack device 10) according to an embodiment includes a cell stack 11 and a conductive member 18. The cell stack 11 has a plurality of element units 3 aligned in a first direction. The conductive members 18 are located between the plurality of element units 3. The cell stack 11 has a first region R1 located in the center in the first direction and a second region R2 located at an end in the first direction. The conductive member 18 located in the first region R1 has a first portion 181 and a second portion 182 having a lower resistivity than the first portion 181. The conductive member 183 located in the second region R2 has a higher resistivity than the second portion 182. This makes it possible to provide a conductive member 18 with high durability.

An electrochemical cell device (e.g., cell stack device 10) of the present disclosure includes a cell stack 11 and a conductive member 18. The cell stack 11 has a plurality of element units 3 aligned in a first direction. The conductive members 18 are located between the plurality of element units 3. The cell stack 11 has a first region R1 located in the center in the first direction and a second region R2 located at an end in the first direction. The conductive member 18 located in the first region R1 has a first member 18A and a second member 18B having a lower resistivity than the first member 18A. The conductive member 183 located in the second region R2 has a higher resistivity than the second member 18B. This makes it possible to provide an electrochemical cell device with high durability.

The module 100 of the present disclosure also includes the electrochemical cell device described above and a storage container 101 that houses the electrochemical cell device. This allows for a highly durable module 100.

The module housing device 110 of the present disclosure also includes the module 100 described above, auxiliary equipment for operating the module 100, and an exterior case 111 for housing the module 100 and auxiliary equipment. This allows for a highly durable module housing device 110.

The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. Indeed, the above-described embodiments may be embodied in a variety of forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

REFERENCE SIGNS LIST 1 Cell 3 Element section 10 Cell stack device 11 Cell stack 12 Fixing member 13 Fixing material 14 Supporting member 15 Support body 16 Gas tank 17 End current collecting member 18 Conductive member 100 Module 110 Module accommodating device 181 First portion 182 Second portion 183 Conductive member

Claims (4)

a cell stack having a plurality of element units aligned in a first direction;
and a conductive member located between each of the plurality of element portions,
the cell stack has a first region located in a center portion in the first direction and a second region located at an end portion in the first direction,
the conductive member located in the first region has a first portion located in a central portion in a second direction intersecting the first direction , and a second portion located at an end portion in the second direction and having a resistivity lower than that of the first portion,
The conductive member located in the second region has a higher resistivity than the second portion. The electrochemical cell device according to claim 1 , wherein the first region has a higher maximum temperature than the second region. The electrochemical cell device according to claim 1 or 2 ;
a housing container for housing the electrochemical cell device. A module according to claim 3 ;
Auxiliary equipment for operating the module;
an outer case that houses the module and the auxiliary equipment.