Patent Application
20250118785
The present disclosure relates to an electrochemical cell, an electrochemical cell device, a module, and a module housing device.
In recent years, various fuel cell stack devices each including a plurality of fuel cells have been proposed, as next-generation energy. A fuel cell is a type of electrochemical cell capable of obtaining electrical power by using a fuel gas such as a hydrogen-containing gas and an oxygen-containing gas such as air.
In an aspect of an embodiment, an electrochemical cell includes a first electrode layer, a second electrode layer, and a solid electrolyte layer. The solid electrolyte layer is located between the first electrode layer and the second electrode layer, and has oxide ion conductivity. The first electrode layer includes an electron conductive material and a first material containing, as a main component, a first element having an electronegativity smaller than that of zirconium.
An electrochemical cell device of the present disclosure includes a cell stack containing the electrochemical cell described above.
A module of the present disclosure includes the electrochemical cell device described above and a storage container housing the electrochemical cell device.
Further, a module housing device of the present disclosure includes the module described above, an auxiliary device for operating the module, and an external case that houses the module and the auxiliary device.
Embodiments of an electrochemical cell, an electrochemical cell device, a module and a module housing device disclosed in the present application will now be described in detail with reference to the accompanying drawings. Note that the disclosure is not limited by the following embodiments.
Note that the drawings are schematic and that the dimensional relationships between elements, the proportions of the elements, and the like may differ from the actual ones. Further, there may be differences between the drawings in the dimensional relationships, proportions, and the like.
First, with reference to
In the example illustrated in
As illustrated in
The element portion 3 is provided on the first surface n1 of the support substrate 2. The element portion 3 includes a fuel electrode layer 5, a solid electrolyte layer 6, and an air electrode layer 8. In the example illustrated in
As illustrated in
Hereinafter, each of constituent members constituting the cell 1 will be described.
The support substrate 2 includes gas-flow passages 2a, in which gas flows. The example of the support substrate 2 illustrated in
The material of the support substrate 2 includes, for example, an iron group metal component and an inorganic oxide. For example, 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 Y, for example.
The fuel electrode layer 5 includes an electron conductive material and a first material containing a first element having an electronegativity smaller than that of zirconium as a main component. The fuel electrode layer 5 is an example of the first electrode layer.
The open porosity of the fuel electrode layer 5 may be, for example, 15% or more, and particularly may be in a range from 20% to 40%. The thickness of the fuel electrode layer 5 may be, for example, from 1 μm to 30 μm. Details of the fuel electrode layer 5 will be described later.
The solid electrolyte layer 6 is an electrolyte and delivers ions between the fuel electrode layer 5 and the air electrode layer 8. At the same time, the solid electrolyte layer 6 has gas blocking properties, and makes leakage of the fuel gas and the oxygen-containing gas less likely to occur.
The solid electrolyte layer 6 has oxide ion conductivity. The solid electrolyte layer 6 may contain Zr, for example. The material of the solid electrolyte layer 6 may be, for example, ZrO2 in which from 3 mole % to 15 mole % of a rare earth element oxide, calcium oxide, or magnesium oxide is contained as a solid solution. The rare earth element oxide may contain, for example, one or more rare earth elements selected from Sc, Y, La, Nd, Sm, Gd, Dy, and Yb. The material of the solid electrolyte layer 6 may be, for example, stabilized zirconia containing Yb. The material of the solid electrolyte layer 6 may be, for example, a ceria-based material in which La, Sm, or Gd is contained as a solid solution, or may be a lanthanum gallate-based perovskite compound. The solid electrolyte layer 6 may further contain, for example, a perovskite compound represented by the formula ABO3 and having proton conductivity. Note that, in the formula ABO3, A is, for example, one or more elements selected from Ca, Sr, Ba and La, and B is, for example, one or more elements selected from Zr, Ce, Sn and Sc. In the perovskite compound having proton conductivity, a rare earth element such as Sc, Y, La, Nd, Sm, Gd, Dy, or Yb may be contained as a solid solution.
The air electrode layer 8 has gas permeability. The air electrode layer 8 is an example of the second electrode layer. The open porosity of the air electrode layer 8 may be, for example, in the range from 20% to 50%, particularly from 30% to 50%.
The material of the air electrode layer 8 is not particularly limited as long as the material is commonly used for the air electrode. The material of the air electrode layer 8 may be, for example, an electrically conductive ceramic such as a so-called ABO3-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 in the A-site. Examples of such a composite oxide include LaxSr1−xCoyFe1−yO3, LaxSr1−xMnO3, LaxSr1−xFeO3, and LaxSr1−xCoO3. Here, x is 0<x<1, and y is 0<y<1.
When the element portion 3 includes the intermediate layer 7, the intermediate layer 7 functions as a diffusion prevention layer. When an element such as strontium (Sr) contained in the air electrode layer 8 diffuses into the solid electrolyte layer 6, a resistance layer such as, for example, SrZrO3 is formed in the solid electrolyte layer 6. The intermediate layer 7 makes it difficult to diffuse Sr, thereby making it difficult to form SrZrO3 and other oxides having electrical insulation.
The material of the intermediate layer 7 is not particularly limited as long as the material is one generally used for the diffusion prevention layer of elements between the air electrode layer 8 and the solid electrolyte layer 6. The material of the intermediate layer 7 may contain, for example, CeO2 (cerium oxide) in which rare earth elements other than Ce (cerium) are in solid solution. As such rare earth elements, for example, Gd (gadolinium), Sm (samarium), or the like may be used.
The interconnector 4 is dense, and makes the leakage of the fuel gas flowing through the gas-flow passages 2a located inside the support substrate 2, and of the oxygen-containing gas flowing outside the support substrate 2 less likely to occur. The interconnector 4 may have a relative density of 93% or more; particularly 95% or more.
As the material of the interconnector 4, a lanthanum chromite-based perovskite-type oxide (LaCrO3-based oxide), a lanthanum strontium titanium-based perovskite-type oxide (LaSrTiO3-based oxide), or the like may be used. These materials have electrical conductivity, and are unlikely to be reduced and also unlikely to be oxidized even when brought into contact with a fuel gas such as a hydrogen-containing gas and an oxygen-containing gas such as air. A metal or an alloy may be used as the material of the interconnector 4.
An electrochemical cell device according to the present embodiment using the electrochemical cell described above will be described with reference to
As illustrated in
The fixing member 12 includes a fixing material 13 and a support member 14. The support member 14 supports the cells 1. The fixing material 13 fixes the cells 1 to the support member 14. The support member 14 includes a support body 15 and a gas tank 16. The support body 15 and the gas tank 16, constituting the support member 14, are made of metal and electrically conductive, for example.
As illustrated in
The gas tank 16 includes an opening portion through which a reactive gas is supplied to the plurality of cells 1 via the insertion hole 15a, and a recessed groove 16a located in the periphery of the opening portion. The outer peripheral end portion of the support body 15 is bonded to the gas tank 16 by a bonding material 21, with which the recessed groove 16a of the gas tank 16 is filled.
In the example illustrated in
A hydrogen-rich fuel gas can be produced, for example, by steam-reforming a raw fuel. When the fuel gas is produced by steam-reforming, the fuel gas contains steam.
In the example illustrated in
The insertion hole 15a has, for example, an oval shape in a top surface view. The length of the insertion hole 15a in an arrangement direction of the cells 1, that is, the thickness direction T, may be longer than the distance between two end current collection members 17 located at both ends of the cell stack 11, for example. The width of the insertion hole 15a may be, for example, greater than the length of the cell 1 in the width direction W (see
As illustrated in
The fixing material 13 and the bonding material 21 may be of low electrical conductivity, such as glass. As the specific materials of the fixing material 13 and the bonding material 21, amorphous glass or the like may be used, and especially, crystallized glass or the like may be used.
As the crystallized glass, for example, any one selected from the group consisting of SiO2—CaO-based, MgO—B2O3-based, La2O3—B2O3—MgO-based, La2O3—B2O3—ZnO-based, and SiO2—CaO—ZnO-based materials may be used, or, in particular, a SiO2—MgO-based material may be used.
As illustrated in
As illustrated in
As illustrated in
The positive electrode terminal 19A functions as a positive electrode when the electrical power generated by the cell stack 11 is output to the outside, and is electrically connected to the end current collection member 17 on a positive electrode side in the cell stack 11A. The negative electrode terminal 19B functions as a negative electrode when the electrical power generated by the cell stack 11 is output to the outside, and is electrically connected to the end current collection member 17 on a negative electrode side in the cell stack 11B.
The connection terminal 19C electrically connects the end current collection member 17 on the negative electrode side in the cell stack 11A and the end current collection member 17 on the positive electrode side in the cell stack 11B.
Details of the fuel electrode layer 5 according to the first embodiment will be described next with reference to
As illustrated in
The electron conductive material 5A may be a porous conductive ceramic containing a material having electrical conductivity and a material having ion conductivity. The material having electrical conductivity is responsible for electron conduction in the fuel electrode layer 5, and the material having ion conductivity is responsible for ion conduction in the fuel electrode layer 5 to promote the reaction between hydrogen and oxygen. As the electron conductive material 5A, for example, ceramics containing: ZrO2 in which a calcium oxide, a magnesium oxide, or a rare earth element oxide is contained as a solid solution, and Ni and/or NiO may be used. This rare earth element oxide may contain a rare earth element selected from, for example, Sc, Y, La, Nd, Sm, Gd, Dy, and Yb. Hereinafter, ZrO2 in which a calcium oxide, a magnesium oxide, or a rare earth element oxide is contained as a solid solution may be referred to as stabilized zirconia. Stabilized zirconia also includes partially stabilized zirconia. Stabilized zirconia is an example of a material having ion conductivity, and Ni and/or NiO is an example of a material having electrical conductivity. The fuel electrode layer 5 may contain a plurality of types of electron conductive materials 5A.
The first material 5B contains a first element having an electronegativity smaller than that of zirconium as a main component. The first element may contain, for example, an alkaline earth metal such as Ca, Sr, Ba and/or a rare earth element such as Sc, Y, La, Nd, Sm, Eu, Gd, Tb, Dy and Yb, in particular a rare earth element selected from La, Nd, Sm, Eu and Yb. “Contains a first element as a main component” refers to, for example, an element occupying 30 mole % or more in terms of oxide. That is, the first material 5B may contain a plurality of first elements.
The first element may be contained in the first material 5B as, for example, an oxide. The first element may be, for example, contained in the first material 5B as a perovskite compound represented by ABO3. In such a case, the first element may be included in, for example, the A-site. A B-site may contain, for example, any element of Zr, Ce, Ti, and Hf.
When the fuel electrode layer 5 includes the first material 5B having the first element, for example, the number of reaction paths in the fuel electrode layer 5 is increased, and thus the electrode resistance is expected to decrease. The reason the number of reaction paths in the fuel electrode layer 5 increases is considered to be that the first element having a low electronegativity and easily attracting a hydroxyl group (OH−) serves as a supply source of the hydroxyl group and promotes the reaction with hydrogen. Thus, with the cell 1 according to the present embodiment, power generation capability can be improved.
When a surface of the fuel electrode layer 5 located on a side opposite to the solid electrolyte layer 6 is defined as a first surface and a surface in contact with the solid electrolyte layer 6 is defined as a second surface, the first material 5B may be included in a larger amount in a site closer to the second surface than to the first surface. The first material 5B may be a first particle containing an oxide including the first element. More of the first particles may be located at a site closer to the second surface than to the first surface. When the first material 5B is contained in a large amount in a site close to the second surface as described above, the cell performances can be further enhanced. Note that, when the fuel electrode layer 5 contains a plurality of first elements, the content of the first element is the total content of the plurality of first elements. The content of the first element is a molar ratio (mole %) of the first element in terms of oxide to the total of the elements contained in the fuel electrode layer 5 in terms of oxide at a predetermined site. The content of the first element in the fuel electrode layer 5 can be confirmed by, for example, elemental analysis using EPMA. Note that, the element contained in the fuel electrode layer 5 is an element detected from the electron conductive material 5A and the first material 5B contained in a predetermined site of the fuel electrode layer 5.
Descriptions of the module according to the present embodiment using the above-described electrochemical cell device will now be given with reference to
As illustrated in
The reformer 102 generates a fuel gas by reforming a raw fuel such as natural gas and kerosene, and supplies the fuel gas to the cell 1. The raw fuel is supplied to the reformer 102 through a raw fuel supply pipe 103. Note that the reformer 102 may include a vaporizing unit 102a for vaporizing water and a reforming unit 102b. The reforming unit 102b includes a reforming catalyst (not illustrated) for reforming the raw fuel into a fuel gas. Such a reformer 102 can perform steam reforming, which is a highly efficient reformation reaction.
Then, the fuel gas generated by the reformer 102 is supplied to the gas-flow passages 2a (see
In the module 100 having the configuration mentioned above, the temperature in the module 100 during normal power generation is about from 500° C. to 1000° C. due to combustion of gas and power generation by the cell 1.
The above-discussed module 100 is configured such that the cell stack device 10 with improved power generation capability is housed therein as described above, whereby the module 100 with the improved power generation capability can be realized.
The external case 111 of the module housing device 110 illustrated in
The dividing plate 114 includes an air circulation hole 117 for causing air in the auxiliary device housing room 116 to flow into the module housing room 115 side. The external plate 113 constituting the module housing room 115 includes an exhaust hole 118 for discharging air inside the module housing room 115.
In the module housing device 110 discussed above, the module 100 with improved power generation capability is provided in the module housing room 115 as described above, whereby the module housing device 110 with improved power generation capability can be realized.
Note that, in the embodiment described above, the case where the support substrate of the hollow flat plate-shaped is used has been exemplified; however, the embodiment can also be applied to a cell stack device using a cylindrical support substrate.
Next, an electrochemical cell and an electrochemical cell device according to a second embodiment will be described with reference to
In the embodiment described above, a so-called “vertically striped type” electrochemical cell device, in which only one element portion including the fuel electrode layer, the solid electrolyte layer, and the air electrode layer is provided on the surface of the support substrate, is exemplified. However, the present disclosure can be applied to a horizontally striped type electrochemical cell device with an array of so-called “horizontally striped type” electrochemical cells, in which a plurality of element portions are provided on the surface of the support substrate at mutually separated locations, and adjacent element portions are electrically connected to each other.
As illustrated in
The cells 1A are electrically connected to each other via connecting members 31. Each of the connecting members 31 is located between the element portions 3 each included in a corresponding one of the cells 1A and electrically connects adjacent ones of the cells 1A to each other. Specifically, the connecting member 31 electrically connects the air electrode layer 8 of the element portion 3 of one of the adjacent ones of the cells 1A to the fuel electrode layer 5 of the element portion 3 of the other one of the adjacent ones of the cells 1A.
As illustrated in
The pair of element portions 3 are located on the first surface n1 and the second surface n2 of the support substrate 2 so as to face each other. The sealing portion 30 is located to cover the side surface m of the support substrate 2.
The cell 1A has a shape that is vertically symmetric with respect to a plane that passes through a center in the thickness direction T and is parallel to the flat surface of the support substrate 2. The element portion 3 includes a fuel electrode layer 5, a solid electrolyte layer 6, an intermediate layer 7, and an air electrode layer 8 which are layered.
When the fuel electrode layer 5 includes the first material 5B having the first element, for example, the number of reaction paths in the fuel electrode layer 5 is increased, and thus the electrode resistance decreases. Thus, in the present embodiment, the cell 1A can improve power generation capability.
As illustrated in
As illustrated in
The support member 94 may be a so-called separator that separates the flow passage 98 of the fuel gas and the flow passage 97 of the oxygen-containing gas. The material of the support members 94 and 95 may be, for example, an electrically conductive metal, or may be an insulating ceramic. When the bonding material 93 is, for example, insulating glass, both the support members 94 and 95 may be metal, or one of the support members 94 and 95 may be an insulating material. When the bonding material 93 is an electrically conductive metal, both or one of the support members 94 and 95 may be an insulating material. When the support members 94 and 95 are metal, the support members 94 and 95 may be formed integrally with the electrically conductive member 92.
One of the bonding material 93 and the support members 94 and 95 has insulating properties and causes the two electrically conductive members 91 and 92 sandwiching the flat plate cell to be electrically insulated from each other.
When the fuel electrode layer 5 includes the first material 5B having the first element, for example, the number of reaction paths in the fuel electrode layer 5 is increased, and thus the electrode resistance decreases. Thus, in the present embodiment, the cell 1B can improve power generation capability.
As illustrated in
In the example illustrated in
The gas-flow passage 2a of the support substrate 2 may be made of the member 120 having unevenness as illustrated in
When the fuel electrode layer 5 includes the first material 5B having the first element, for example, the number of reaction paths in the fuel electrode layer 5 is increased, and thus the electrode resistance decreases. Thus, in the present embodiment, the cell 1B can improve power generation capability.
An electrochemical cell device according to other embodiments will be described.
In the above embodiments, a fuel cell, a fuel cell stack device, a fuel cell module, and a fuel cell device are illustrated as examples of the “electrochemical cell”, the “electrochemical cell device”, the “module”, and the “module housing device”; other examples include an electrolytic cell, an electrolytic cell stack device, an electrolytic module, and an electrolytic device, respectively. The electrolytic cell includes a first electrode layer and a second electrode layer, and decomposes water vapor into hydrogen and oxygen or decomposes carbon dioxide into carbon monoxide and oxygen by supplying electric power. Although an oxide ion conductor or a hydrogen ion conductor is shown as an example of the electrolyte material of the electrochemical cell in the above embodiment, the electrolyte material may be a hydroxide ion conductor. According to the electrolytic cell, electrolytic cell stack device, electrolytic module, and electrolytic device discussed above, electrolytic performance can be improved.
While the present disclosure has been described in detail, the present disclosure is not limited to the aforementioned embodiment, and various changes, improvements, and the like can be made without departing from the gist of the present disclosure.
As described above, the electrochemical cell (cell 1) according to the embodiment includes the first electrode layer (fuel electrode layer 5), the second electrode layer (air electrode layer 8), and the solid electrolyte layer 6. The solid electrolyte layer 6 is located between the first electrode layer and the second electrode layer, and has oxide ion conductivity. The first electrode layer includes the electron conductive material 5A and the first material 5B containing a first element having an electronegativity smaller than that of zirconium as a main component. This can improve the cell performance such as power generation capability and electrolytic performance of the electrochemical cell.
The electrochemical cell device (cell stack device 10) according to the present embodiment includes the cell stack 11 containing the electrochemical cell described above. This can improve the performance such as power generation capability and electrolytic performance of the electrochemical cell device.
The module 100 according to the embodiment includes the electrochemical cell device (the cell stack device 10) described above, and the storage container 101 housing the electrochemical cell device. As a result, the module 100 with improved performance can be obtained.
The module housing device 110 according to embodiment includes the module 100 described above, an auxiliary device configured to operate the module 100, and the external case 111 configured to accommodate the module 100 and the auxiliary device. As a result, the module housing device 110 with improved performance can be obtained.
Note that the embodiments disclosed herein are exemplary in all respects and not restrictive. The aforementioned embodiments can be embodied in a variety of forms. The aforementioned embodiments may be omitted, replaced, or changed in various forms without departing from the scope of the appended claims and the purpose thereof.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-176897 | Oct 2021 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/039777 | 10/25/2022 | WO |
