KR20240080057A - Solid oxide cell stack - Google Patents

Abstract

One embodiment of the present invention includes first and second interconnects, a solid oxide cell disposed between the first and second interconnects, and a porous metal foam disposed between the first interconnect and the solid oxide cell, The porous metal foam provides a solid oxide cell stack including carbon nanostructures formed on the surface.

Description

Solid oxide cell stack {SOLID OXIDE CELL STACK}

The present invention relates to solid oxide cell stacks.

A solid oxide fuel cell (SOFC) and a solid oxide electrolysis cell (SOEC) include a cell composed of an air electrode, a fuel electrode, and a solid electrolyte with oxygen ion conductivity, where the cell is a solid It can be referred to as an oxide cell. Solid oxide cells produce electrical energy through an electrochemical reaction or produce hydrogen by electrolyzing water through the reverse reaction of a solid oxide fuel cell. Solid oxide cells are compared to other types of fuel cells or water electrolytic cells, such as phosphoric acid fuel cells (PAFC), alkaline fuel cells (AFC), polymer electrolyte fuel cells (PEMFC), and direct methanol fuel cells (DMFC). Based on low activation polarization, overvoltage is low and irreversible loss is low, so efficiency is high. In addition, it can be used as a carbon or hydrocarbon-based fuel in addition to hydrogen, giving a wide range of fuel choices, and has the advantage of not requiring expensive precious metals as an electrode catalyst because the reaction rate at the electrode is high.

The solid oxide cell can be used as a stack structure disposed between a pair of interconnects. In this case, to improve reliability, sufficient electrical/structural connectivity between the interconnect and the solid oxide cell needs to be secured.

One of the purposes of the present invention is to implement a solid oxide cell stack in which electrical and structural connectivity between the interconnect and the solid oxide cell can be improved.

As a method for solving the above-described problem, the present invention seeks to propose a novel structure of a solid oxide cell stack through an example, specifically, first and second interconnects, and between the first and second interconnects. It is disposed between a solid oxide cell and the first interconnect and the solid oxide cell and includes a porous metal foam, wherein the porous metal foam includes a carbon nanostructure formed on the surface.

In one embodiment, the carbon nanostructure may include at least one of carbon nanotubes and carbon nanofibers.

In one embodiment, the carbon nanostructure may be formed on the surface of the porous metal foam that contacts the solid oxide.

In one embodiment, the carbon nanostructure may be formed on a surface opposite to the surface in contact with the solid oxide in the porous metal foam.

In one embodiment, the carbon nanostructure may be formed on the entire surface and interior of the porous metal foam.

In one embodiment, the carbon nanostructure may be arranged perpendicular to the surface of the porous metal foam.

In one embodiment, the carbon nanostructure may be arranged in a shape inclined in a random direction with respect to the surface of the porous metal foam.

In one embodiment, the porous metal foam may include Ni.

In one embodiment, the porous metal foam is an elastic body, and the porous metal foam may be compressed by the first interconnect and the solid oxide cell.

In one embodiment, the solid oxide cell includes a fuel electrode and an air electrode and an electrolyte disposed between them, the fuel electrode may be disposed on the first interconnect side, and the air electrode may be disposed on the second interconnect side.

In one embodiment, when the porous metal foam is referred to as a first porous metal foam, it may further include a second porous metal foam disposed between the second interconnect and the solid oxide cell.

In one embodiment, the second porous metal foam may include a Cu alloy.

In one embodiment, it further includes first and second end plates, and the first and second interconnects, the solid oxide cell, and the porous metal foam may be disposed between the first and second end plates.

In one embodiment, a structure in which the first interconnect, the porous metal foam, the solid oxide cell, and the second interconnect are repeated two or more times in the direction from the first end plate to the second end plate. You can have it.

In one embodiment, the porous metal foam may further include a protective film formed on the surface of the carbon nanostructure.

In one embodiment, the protective film may include at least one of B and Al.

In the case of the solid oxide cell stack according to an example of the present invention, reliability can be improved as electrical and structural connectivity between the interconnect and the solid oxide cell is secured. Therefore, performance can be improved when using this solid oxide cell stack as a fuel cell or water electrolysis cell.

1 is an exploded perspective view schematically showing a solid oxide cell stack according to an embodiment of the present invention.
2 and 3 are cross-sectional views of one area of a solid oxide cell stack.
Figure 4 shows an example of metal foam being compressed in the solid oxide cell stack of Figure 2.
5 to 8 show examples of metal foams that can be used in solid oxide cell stacks.
Figure 9 shows an example of a carbon nanostructure that can be used in a solid oxide cell stack.
10 and 11 show a solid oxide cell stack according to a modified example.

Hereinafter, embodiments of the present invention will be described with reference to specific embodiments and attached drawings. However, the embodiments of the present invention may be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. Additionally, embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. Accordingly, the shapes and sizes of elements in the drawings may be exaggerated for clearer explanation, and elements indicated by the same symbol in the drawings are the same elements.

In order to clearly explain the present invention in the drawings, parts that are not relevant to the description are omitted, and the thickness is enlarged to clearly express various layers and regions, and components with the same function within the scope of the same idea are referred to by the same reference. Explain using symbols. Furthermore, throughout the specification, when a part is said to “include” a certain element, this means that it may further include other elements rather than excluding other elements, unless specifically stated to the contrary.

1 is an exploded perspective view schematically showing a solid oxide cell stack according to an embodiment of the present invention. 2 and 3 are cross-sectional views of one area of a solid oxide cell stack. Figure 4 shows an example of metal foam being compressed in the solid oxide cell stack of Figure 2. And Figures 5 to 8 show examples of metal foams that can be used in solid oxide cell stacks.

Referring to FIGS. 1 to 5, the solid oxide cell stack 100 according to an embodiment of the present invention includes a first interconnect 111, a solid oxide cell 120, and a second interconnect 112 as main components. And, a porous metal foam (metal foam) 131 is disposed between the first interconnect 111 and the solid oxide cell 120. And the porous metal foam 131 includes a carbon nanostructure 132 formed on the surface. By using the porous metal foam 131 with the carbon nanostructure 132 formed on the surface as in this embodiment, the electrical/structural connectivity between the first interconnect 111 and the solid oxide cell 120 can be improved, thereby improving The performance and durability of the solid oxide cell stack 100 can be improved. Hereinafter, the components of the solid oxide cell stack 100 will be described in detail, and the case where the solid oxide cell stack 100 is used as a fuel cell will mainly be described. However, the solid oxide cell stack 100 can also be used as a water electrolysis cell, and in this case, a reaction opposite to that in the case of a fuel cell will occur at the anode 121 and the air electrode 122 of the solid oxide cell 120.

The first and second interconnects 111 and 112 may be electrically connected to the solid oxide cell 120. For example, when the solid oxide cell stack 100 includes a stacked structure of a plurality of solid oxide cells 120, adjacent It can be placed between the solid oxide cells 120 and connect them. The first and second interconnects 111 and 112 may have a flat structure and may include passages through which gas can diffuse, through holes, etc. The first and second interconnects 111 and 112 may be made of a material that has excellent electrical conductivity and a low degree of deterioration in a high-temperature environment. As a specific example, the first and second interconnects 111 and 112 may be formed of metal such as stainless steel, nickel, iron, or copper.

The solid oxide cell 120 is disposed between the first and second interconnects 111 and 112 and corresponds to a functional layer of a fuel cell or water electrolysis cell. Specifically, the solid oxide cell 120 may include an anode 121 and an air electrode 122, and an electrolyte 123 disposed between them. In this case, the anode 121 is connected to the first interconnect 111. On the side, the air electrode 122 may be disposed on the second interconnect 112 side. If the solid oxide cell 120 is a fuel cell, for example, water production or an oxidation reaction of a carbon compound may occur due to oxidation of hydrogen in the anode 121, and an oxygen ion generation reaction due to decomposition of oxygen may occur in the air electrode 122. This can happen. If the solid oxide cell 120 is a water electrolysis cell, the opposite reaction may occur. For example, hydrogen gas may be generated in the anode 121 due to a reduction reaction of water, and oxygen may be generated in the air electrode 122. there is. Also, as another example, in the case of a fuel cell, hydrogen may be decomposed (generating hydrogen ions) in the anode 121, and water may be generated by combining oxygen and hydrogen ions in the air electrode 122. In the case of a water electrolysis cell, , a reaction of water decomposition (generating hydrogen and oxygen ions) occurs at the anode 121, and oxygen may be generated at the air electrode 122. And ions can move from the electrolyte 123 to the anode 121 or the air electrode 122.

The fuel electrode 121, electrolyte 123, and air electrode 122 may include solid oxide. Specifically, the anode 121 may include a cermet layer including a metal-containing phase and a ceramic phase. Here, the metal-containing phase may include a metal catalyst such as nickel (Ni), cobalt (Co), copper (Cu), or an alloy thereof, which acts as an electronic conductor. The metal catalyst may be in a metallic state or may be in an oxide state. In the case of the ceramic phase of the anode 121, Gadolinia doped ceria (GDC), Samaria doped ceria (SDC), Ytterbia doped ceria (YDC), Scandia stabilized zirconia (SSZ), Ytterbia ceria Scandia stabilized zirconia ( YbCSSZ), etc.

Electrolyte 123 may include stabilized zirconia. Specifically, the electrolyte 123 includes Scandia stabilized zirconia (SSZ), yttria stabilized zirconia (YSZ), Scandia ceria stabilized zirconia (SCSZ), Scandia ceria yttria stabilized zirconia (SCYSZ), and Scandia ceria ytterbia stabilized zirconia (SCYbSZ). It may include etc.

Air electrode 122 may include an electrically conductive material, such as an electrically conductive perovskite material such as lanthanum strontium manganite (LSM). Other conducting perovskites, such as lanthanum strontium cobalt (LSC), lanthanum strontium cobalt manganese (LSCM), lanthanum strontium cobalt ferrite (LSCF), lanthanum strontium ferrite (LSF), La _0.85 Sr _0.15 Cr _0.9 Ni _0.1 O ₃ (LSCN) ) or metals such as Pt can also be used. In some embodiments, cathode 122 may include a mixture of an electrically conductive material and an ionically conductive ceramic material. For example, the cathode 122 may include about 10% to about 90% by weight of an electrically conductive material (e.g., LSM, etc.) and about 10% to about 90% by weight of an ionically conductive material. Here, the ion-conducting material may include zirconia-based and/or ceria-based materials.

Meanwhile, in the embodiment of FIG. 2, a portion of the solid oxide cell 120 and the porous metal foam 131 are exposed to the outside, but a sealing structure may be added to protect them and prevent gas, etc. from leaking. That is, as in the example shown in FIG. 3, a sealing portion 140 covering the side surfaces of the solid oxide cell 120 and the porous metal foam 131 may be further provided. The sealing portion 140 may be formed of a glass-based material. In this case, the tissue becomes dense at high temperatures and can prevent liquid or gas from leaking. In addition to this, the sealing portion 140 may also include a frame or gasket structure. Additionally, depending on the embodiment, an additional sealing part may be further provided to seal the first and second interconnects 111 and 112.

The porous metal foam 131 is disposed between the first interconnect 111 and the solid oxide cell 120 and includes a carbon nanostructure 132 formed on the surface. The porous metal foam 131 may be implemented as, for example, a foam-type metal body structure, a sponge structure in which metal wires are entangled, etc. As a more specific example, considering that the anode 121 side may be in a reducing atmosphere when the solid oxide cell 120 cell is driven, the porous metal foam 131 may be implemented as Ni foam containing Ni. You can. The porous metal foam 131 may be an elastic body and may be compressed by the first interconnect 111 and the solid oxide cell 120, as can be seen in the example shown in FIG. 4. Since the porous metal foam 131 contains pores H therein, the first interconnect 111 and the solid oxide cell 120 can be electrically connected without interfering with the flow of fuel.

The carbon nanostructure 132 formed on the surface of the porous metal foam 131 may include at least one of carbon nano tubes and carbon nano fibers. As an example, the carbon nanostructure 132 may be formed to have a diameter of several nanometers to several tens of nanometers and a length of several μm to several millimeters. As shown, the carbon nanostructure 132 can be formed on the surface (S1) in contact with the solid oxide 120 in the porous metal foam 131, which is in contact with the solid oxide 120 (S1). ), taking into account the importance of connectivity. In FIG. 5 , the hatched area on the surface (S1) in contact with the solid oxide 120 represents the area where the carbon nanostructure 132 is formed. In addition, as shown in the example shown in FIG. 7, the carbon nanostructure 132 may be formed on the surface S1 opposite to the surface S1 in contact with the solid oxide in the porous metal foam 131. Additionally, as in the example shown in FIG. 8, the carbon nanostructure 132 may be formed on the entire surface and interior of the porous metal foam 131.

Referring to the enlarged area of S1 in FIG. 5, the carbon nanostructure 132 may be arranged perpendicular to the surface of the porous metal foam 131. This vertical arrangement method can be obtained by growing the carbon nanostructure 132 on the surface of the porous metal foam 131. Here, the carbon nanostructure 132 can be grown using methods such as chemical vapor deposition or thermal vapor deposition. Also, as another example, as shown in Figure 6, the carbon nanostructure 132 may be arranged in a shape inclined in a random direction with respect to the surface of the porous metal foam 131. This random arrangement method is used by pre-manufactured It can be obtained by attaching the carbon nanostructure 132 to the surface of the porous metal foam 131.

As in the present embodiment, when the porous metal foam 131 having the carbon nanostructure 132 is disposed between the first interconnect 111 and the solid oxide cell 120, the electrical characteristics of the solid oxide cell stack 100 or structural stability can be improved. When driving the solid oxide cell stack 100, the connectivity between the first interconnect 111 and the solid oxide cell 120 may be reduced due to deformation due to vibration, etc., and the porous metal foam 131 is the first interconnect even in this environment. The connection between (111) and the solid oxide cell (120) can be maintained, and by including a large number of pores (H), fuel, etc. can pass through effectively. For this purpose, as described above, the porous metal foam 131 may have elasticity. And, by forming the carbon nanostructure 132 on the surface of the porous metal foam 131, the electrical resistance between the first interconnect 111 and the solid oxide cell 120 can be further lowered. Furthermore, the carbon nanostructure 132 can be oriented in various directions, which can further improve resistance to mechanical deformation or contamination.

Meanwhile, as shown in FIG. 9, the porous metal foam 131 may further include a protective film 133 formed on the surface of the carbon nanostructure 132. The protective film 133 may perform functions such as protecting the carbon nanostructure 132 and preventing oxidation, and may include, for example, at least one of B and Al. In this case, the protective film 133 may be formed of a metal of B or Al or an oxide of B or Al.

Modified examples will be described with reference to FIGS. 10 and 11 . First, in the case of FIG. 10, in the above-described embodiment, the porous metal foam 132 is additionally disposed on the second interconnect 112 side. That is, the second porous metal foam 132 disposed between the second interconnect 112 and the solid oxide cell 120 is further disposed, and in this case, the first porous metal foam 132 disposed on the side of the first interconnect 111 is It can be referred to as form 131. As the second porous metal foam 132 is further provided, electrical connectivity and durability between the solid oxide cell 120 and the second interconnect 112 can be improved. The second porous metal foam 132 may be operated in an oxidizing atmosphere and, taking this into account, may be formed of a material containing a Cu alloy, for example, a Cu-Mn alloy.

이하 정도로 낮다면 전도전도도가 좋은 구리나 구리 합금 등도 사용할 수 있을 것이다.Next, the embodiment of FIG. 11 further includes first and second end plates 151 and 152, first and second interconnects 111 and 112, a solid oxide cell 120, and a porous metal foam 131. may be disposed between the first and second end plates 151 and 152. In this case, in the direction from the first end plate 131 to the second end plate 132 (direction toward the top based on the drawing), the first interconnect 111, the porous metal foam 131, and the solid oxide cell It may have a structure in which the order of (120) and the second interconnect (112) is repeated two or more times. As a result, the plurality of solid oxide cells 120 are connected in series to improve output, making it possible to obtain higher voltage electricity than hydrogen generation in the case of a water electrolysis cell or higher voltage in the case of a fuel cell. The first and second end plates 151 and 152 may include a metal with a high melting point so that the solid oxide cell 120 does not melt or soften even when operated at high temperature, and may have a plate-like structure of this metal. For example, the first and second end plates 151 and 152 may be made of nickel-based, iron-based, or stainless-based materials. In addition, when the operating temperature of the solid oxide cell stack 100 is relatively low, for example, 800

If it is low, copper or copper alloys with good electrical conductivity can also be used.

The present invention is not limited by the above-described embodiments and attached drawings, but is limited by the attached claims. Therefore, it will be apparent to those skilled in the art that various forms of substitution, modification, and change are possible without departing from the technical spirit of the present invention as set forth in the claims, and this is also subject to the appended claims. It may be said to belong to the technical idea described in .

100: solid oxide cell stack
111, 112: interconnect
120: solid oxide cell
121: fuel electrode
122: Air electrode
123: electrolyte
131: Porous metal foam
132: Carbon nanostructure
133: Shield
140: Sealing part
151, 152: End plate

Claims (16)

first and second interconnects;
a solid oxide cell disposed between the first and second interconnects; and
It includes a porous metal foam disposed between the first interconnect and the solid oxide cell,
The porous metal foam is a solid oxide cell stack including carbon nanostructures formed on the surface.
According to paragraph 1,
The carbon nanostructure is a solid oxide cell stack including at least one of carbon nanotubes and carbon nanofibers.
According to paragraph 1,
The carbon nanostructure is a solid oxide cell stack formed on the surface of the porous metal foam in contact with the solid oxide.
According to paragraph 3,
The carbon nanostructure is a solid oxide cell stack formed on a surface opposite to the surface in contact with the solid oxide in the porous metal foam.
According to paragraph 4,
The carbon nanostructure is a solid oxide cell stack formed on the entire surface and interior of the porous metal foam.
According to paragraph 1,
The carbon nanostructure is a solid oxide cell stack arranged perpendicular to the surface of the porous metal foam.
According to paragraph 1,
The carbon nanostructure is a solid oxide cell stack arranged in a shape inclined in a random direction with respect to the surface of the porous metal foam.
According to paragraph 1,
The porous metal foam is a solid oxide cell stack containing Ni.
According to paragraph 1,
The porous metal foam is an elastic body, and the porous metal foam is compressed by the first interconnect and the solid oxide cell.
According to paragraph 1,
The solid oxide cell includes a fuel electrode and an air electrode and an electrolyte disposed between them, wherein the fuel electrode is disposed on the first interconnect side, and the air electrode is disposed on the second interconnect side.
According to clause 10,
When the porous metal foam is referred to as the first porous metal foam,
A solid oxide cell stack further comprising a second porous metal foam disposed between the second interconnect and the solid oxide cell.
According to clause 11,
The second porous metal foam is a solid oxide cell stack containing a Cu alloy.
According to paragraph 1,
Further comprising first and second end plates,
A solid oxide cell stack wherein the first and second interconnects, the solid oxide cell, and the porous metal foam are disposed between the first and second end plates.
According to clause 13,
A solid oxide cell stack having a structure in which the first interconnect, the porous metal foam, the solid oxide cell, and the second interconnect are repeated two or more times in the direction from the first end plate to the second end plate. .
According to paragraph 1,
The porous metal foam is a solid oxide cell stack further comprising a protective film formed on the surface of the carbon nanostructure.
According to clause 15,
The protective film is a solid oxide cell stack containing at least one of B and Al.