KR20240085114A - Solid oxide cell and manufacturing method thereof - Google Patents

Abstract

A solid oxide cell according to an embodiment includes a fuel electrode and an air electrode facing each other, and an electrolyte layer located between the fuel electrode and the air electrode, the fuel electrode has a flat shape, and the edge of the fuel electrode is in the thickness direction of the fuel electrode. It is rounded along, and the anode includes a central layer and outer layers located on both sides of the central layer, and the first porosity, which is the porosity of the central layer of the anode, is smaller than the second porosity, which is the porosity of the outer layer of the anode. .

Description

Solid oxide cell and method of manufacturing the same {SOLID OXIDE CELL AND MANUFACTURING METHOD THEREOF}

This disclosure relates to solid oxide cells and methods of manufacturing the same.

Generally, a solid oxide cell (SOC) includes a solid oxide electrolysis cell (SOEC) and a solid oxide fuel cell (SOFC) of approximately the same structure.

A solid oxide electrolysis cell (SOEC) is a device that generates hydrogen by electrolyzing water. It is possible to produce green hydrogen using electricity generated from renewable energy such as solar and wind power. It is essential for future carbon neutrality and hydrogen economy. In particular, the solid oxide electrolysis cell (SOEC) is an eco-friendly energy conversion device as it operates at high temperatures and has high efficiency and no carbon emissions.

In addition, a solid oxide fuel cell (SOFC) is a device that produces electricity using the reverse reaction of the electrolysis reaction of water. It has low irreversible loss, so it has high power generation efficiency and can use a variety of fuels without a reformer. As a result, not only hydrogen but also carbon or hydrocarbon-based fuels can be used, providing a wide range of fuel choices, and the reaction speed at the electrode is fast, so it has several advantages in that it does not require expensive precious metal catalysts.

Electrolytes and electrodes of unit cells used in solid oxide electrolysis cells (SOEC) and solid oxide fuel cells (SOFC) may be made of solid oxides.

In particular, a flat solid oxide cell (SOC) may include a flat fuel electrode, an electrolyte layer, and an air electrode. At this time, the anode may be applied as an anode support that is thicker and has a larger area than the electrolyte layer and the air electrode.

The edges and corners of the fuel electrode, electrolyte layer, and air electrode of these flat solid oxide cells have sharp, angled shapes, so when unit cells are stacked to form a stack, there is a possibility that the edges and corners may be worn or damaged by impact. This is high.

In addition, when unit cells are stacked, stress and pressure are concentrated on sharp edges and corners due to contact with the sealing material or fastening pressure, so there is a high possibility that the edges and corners will be damaged.

Embodiments are intended to provide a solid oxide cell and a method of manufacturing the same that can minimize damage during stack manufacturing by distributing pressure and stress applied to edges and corners.

However, the problems that the embodiments seek to solve are not limited to the above-described problems and can be expanded in various ways within the scope of the technical ideas included in the embodiments.

A solid oxide cell according to an embodiment includes a fuel electrode and an air electrode facing each other, and an electrolyte layer located between the fuel electrode and the air electrode, the fuel electrode has a flat shape, and the edge of the fuel electrode is in the thickness direction of the fuel electrode. It is rounded along, and the anode includes a central layer and outer layers located on both sides of the central layer, and the first porosity, which is the porosity of the central layer of the anode, is smaller than the second porosity, which is the porosity of the outer layer of the anode. .

A first corner, which is a corner connecting the corners of the fuel electrode, may be rounded along the thickness direction of the fuel electrode.

The first corner may be rounded in plan.

The corners of the fuel electrode have a radius of curvature of 1/2 the thickness of the fuel electrode and may be rounded along the thickness direction of the fuel electrode.

The second corner, which is the corner of the electrolyte layer, and the third corner, which is the corner of the air electrode, may be rounded in plan.

The anode is located between the central layer and the outer layer and further includes an intermediate layer having a third porosity, and the third porosity may be greater than the first porosity and less than the second porosity.

The length of the middle layer may be longer than the length of the central layer and shorter than the length of the outer layer.

In addition, the method of manufacturing a solid oxide cell according to an embodiment includes a central member having a first porosity, and an outer member located on both sides of the central member and having a second porosity greater than the first porosity. Prepare a plurality of anode members, stack and compress the plurality of anode members, stack an electrolyte member on the anode member, and sinter the plurality of anode members and the electrolyte member to form the anode and the electrolyte layer. It includes rounding the corners of the fuel electrode along the thickness direction of the fuel electrode, and forming an air electrode on the electrolyte layer.

By sintering the plurality of anode members, the outer member may shrink more than the central member, so that the length of the outer layer formed by sintering the outer member may be shorter than the length of the central layer formed by sintering the central member.

Preparing the plurality of anode members may include forming first corners of the plurality of anode members to be rounded in a plane.

Stacking the electrolyte member may include forming the second corner, which is a corner of the electrolyte member, to be rounded in a plane.

Forming the air gap may include forming the third corner, which is a corner of the air gap, to be round in plan.

According to embodiments, the first porosity, which is the porosity of the central layer of the anode, is made smaller than the second porosity, which is the porosity of the outer layer of the anode, so that the edges and corners of the anode can be rounded along the thickness direction of the anode.

Therefore, damage to the fuel electrode during stack manufacturing can be minimized by distributing the pressure and stress applied to the edges and corners of the fuel electrode.

In addition, by forming the corners of the electrolyte layer and the air electrode to be rounded, the pressure and stress applied to the corners of the electrolyte layer and the air electrode can be distributed, thereby minimizing damage to the electrolyte layer and the air electrode during stack manufacturing.

However, it is obvious that the effects of the embodiments are not limited to the effects described above and can be expanded in various ways without departing from the spirit and scope of the present invention.

1 is a schematic perspective view of a solid oxide cell according to one embodiment.
Figure 2 is a plan view of Figure 1.
FIG. 3 is a cross-sectional view taken along line III-III' of FIG. 2.
Figure 4 is an enlarged cross-sectional view of portion A of Figure 3.
Figure 5 is a partial enlarged photograph of the central layer and middle layer of Figure 4.
6 and 7 are diagrams illustrating one step of a method for manufacturing a solid oxide cell according to an embodiment.

Hereinafter, with reference to the attached drawings, various embodiments of the present invention will be described in detail so that those skilled in the art can easily practice the present invention. The invention may be implemented in many different forms and is not limited to the embodiments described herein.

In order to clearly explain the present invention, parts that are not relevant to the description are omitted, and identical or similar components are given the same reference numerals throughout the specification.

In addition, the attached drawings are only for easy understanding of the embodiments disclosed in this specification, and the technical idea disclosed in this specification is not limited by the attached drawings, and all changes included in the spirit and technical scope of the present invention are not limited. , should be understood to include equivalents or substitutes.

In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, so the present invention is not necessarily limited to what is shown. In the drawing, the thickness is enlarged to clearly express various layers and regions. And in the drawings, for convenience of explanation, the thicknesses of some layers and regions are exaggerated.

Additionally, when a part of a layer, membrane, region, plate, etc. is said to be “on” or “on” another part, this includes not only cases where it is “directly above” another part, but also cases where there is another part in between. . Conversely, when a part is said to be “right on top” of another part, it means that there is no other part in between. In addition, being “on” or “on” a reference part means being located above or below the reference part, and does not necessarily mean being located “above” or “on” the direction opposite to gravity. .

In addition, throughout the specification, when a part is said to "include" a certain component, this means that it may further include other components rather than excluding other components, unless specifically stated to the contrary.

In addition, throughout the specification, when referring to “on a plane,” this means when the target portion is viewed from above, and when referring to “in cross-section,” this means when a cross section of the target portion is cut vertically and viewed from the side.

In addition, throughout the specification, when "connected" is used, this does not mean that two or more components are directly connected, but rather that two or more components are indirectly connected through other components, or physically connected. It can mean not only being connected but also being electrically connected, or being integrated although referred to by different names depending on location or function.

Hereinafter, various embodiments and modifications will be described in detail with reference to the drawings.

FIG. 1 is a schematic perspective view of a solid oxide cell according to an embodiment, FIG. 2 is a plan view of FIG. 1, FIG. 3 is a cross-sectional view taken along line III-III' of FIG. 2, and FIG. 4 is a plan view of FIG. 3. This is an enlarged cross-sectional view of part A of .

As shown in FIGS. 1 to 3 , a solid oxide cell according to an embodiment includes an anode 100, an electrolyte layer 200, and an air electrode 300 that are sequentially stacked.

The size and thickness of the anode 100 may be larger than those of the electrolyte layer 200 and the air electrode 300. Accordingly, the anode 100 can support the stacked electrolyte layer 200 and the air electrode 300. In the case of a solid oxide electrolysis cell (SOEC), the anode 100 can receive fuel gas such as water (H ₂ O) in a reducing atmosphere and generate hydrogen gas and oxygen ions through electrolysis.

Since the fuel electrode 100 has a square plate shape, it may have four corners 100a and a first corner 100b, which is four corners connecting the four corners 100a.

The corner 100a of the anode 100 is rounded along the thickness direction (Z) of the anode 100, and the first corner 100b of the anode 100 is also rounded along the thickness direction (Z) of the anode 100. It can be.

Therefore, compared to the case where the edge 100a of the anode 100 is straight, the area of the edge 100a of the anode 100 increases, thereby reducing the pressure per unit area. Therefore, strength can be increased from physical impact due to pressure. In this way, the pressure and stress applied to the corner 100a and the first corner 100b of the anode 100 can be distributed to minimize damage to the anode 100 during stack manufacturing.

As shown in FIGS. 3 and 4 , the anode 100 may include a central layer 110, a middle layer 130, and an outer layer 120 that are stacked.

The central layer 110 is located in the center and may have a first shortest length d1. The middle layer 130 includes a first middle layer 131 and a second middle layer 132 positioned opposite to both sides of the middle layer 110, respectively, and may have a second shortest length d2. The outer layer 120 includes a first outer layer 121 and a second outer layer 122 positioned opposite to both sides of the middle layer 130, respectively, and may have a third shortest length d3.

The fuel electrode 100 is a solid oxide with ion conductivity, and is made of yttria stabilized zirconia (Yttria Stabilized ZrO ₂ , YSZ), which is obtained by dissolving yttria (Y ₂ O ₃ ) in zirconia (ZrO ₂ ), and scandium stabilized zirconia (Scandium Stabilized Zirconia). It may include metal oxides such as ScSZ), GDC, and LDC. However, the anode 100 is not necessarily limited to this and may be made of various materials.

Figure 5 is a partial enlarged photograph of the central layer and middle layer of Figure 4.

As shown in FIG. 5, the anode 100 may have a plurality of pores (AG) that serve as a movement path for gas. The first porosity of the central layer 110 of the anode 100 is smaller than the second porosity of the outer layer 120 of the anode 100, and the third porosity of the middle layer 130 of the anode 100 is smaller than the second porosity of the outer layer 120 of the anode 100. The porosity may be greater than the first porosity and smaller than the second porosity. Accordingly, the outer layer 120, which has the highest porosity, may shrink more than the central layer 110 and the middle layer 130 during a sintering process.

As shown in FIG. 4, the central layer 110 is contracted by the first contracted length (W1), but the outer layer 120 is contracted by the second contracted length (W2), which is shorter than the first contracted length (W1). You can. Additionally, the middle layer 130 may be contracted by a third contracted length (W3) that is longer than the first contracted length (W1) and shorter than the second contracted length (W2). Accordingly, the edge 100a of the anode 100 may be rounded along the thickness direction (Z) of the anode 100.

At this time, the edge 100a of the anode 100 has a radius of curvature (R) of 1/2 the thickness (D) of the anode 100 and may be rounded along the thickness direction (Z) of the anode 100. .

In this way, the first porosity of the central layer 110 of the anode 100 is made smaller than the second porosity of the outer layer 120 of the anode 100, so that the corners 100a and the first corner of the anode 100 are formed. (100b) may be rounded along the thickness direction (Z) of the anode 100.

The first corner 100b of the fuel electrode 100 may be rounded in plan. Accordingly, the pressure and stress applied to the first corner 100b of the anode 100 can be further distributed, thereby minimizing damage to the anode 100 during stack manufacturing.

Meanwhile, in the case of a solid oxide electrolysis cell (SOEC), the electrolyte layer 200 can transfer oxygen ions generated in the anode 100 to the air electrode 300.

Since the electrolyte layer 200 has a square plate shape, it may have four corners 200a and second corners 200b, which are four corners connecting the four corners 200a.

The second corner 200b of the electrolyte layer 200 may be rounded in plan. Accordingly, the pressure and stress applied to the second corner 200b of the electrolyte layer 200 can be distributed to minimize damage to the electrolyte layer 200 during stack manufacturing.

In the case of a solid oxide electrolysis cell (SOEC), the air electrode 300 may generate oxygen gas by oxidizing oxygen ions transferred from the electrolyte layer 200 in an oxidizing atmosphere.

The air electrode 300 is made by using lanthanum strontium manganite ((La _0.84 Sr _0.16 ) MnO ₃ ), which has high electronic conductivity, using plasma spray, electrochemical deposition, sputtering, ion beam, and ion injection methods. After coating with a wet method such as dry method, tape casting, spray coating, dip coating, screen printing, or doctor blade method, 1200 It can be formed by sintering at ℃ to 1300 ℃. However, the air electrode 300 is not necessarily limited to this and may be made of various materials.

Since the air electrode 300 has a square plate shape, it may have four corners 300a and a third corner 300b, which is four corners connecting the four corners 300a.

The third corner 300b of the air gap 300 may be rounded in plan. Accordingly, damage to the air electrode during stack manufacturing can be minimized by dispersing the pressure and stress applied to the third corner 300b of the air electrode.

The in-plane curvature radii (r1, r2, r3) of the first corner 100b, the second corner 200b, and the third corner 300b may be the same. Therefore, by uniformly distributing the pressure and stress applied to the first corner 100b, the second corner 200b, and the third corner 300b, damage to the anode 100, the electrolyte layer 200, and the air electrode are prevented. can be further minimized.

Then, with reference to FIGS. 6 and 7 along with FIGS. 1 to 4, a method for manufacturing a solid oxide cell according to an embodiment will be described in detail.

6 and 7 are diagrams illustrating one step of a method for manufacturing a solid oxide cell according to an embodiment.

As shown in FIG. 6, the method for manufacturing a solid oxide cell according to an embodiment first prepares a plurality of anode members 1 having a rectangular flat plate shape. The plurality of anode members 1 may have the same size and thickness. The first corner 100b of the plurality of anode members 1 may be formed to be round in plan.

The plurality of anode members 1 may include a central member 10, an intermediate member 30, and an outer member 20. The central member 10 may have a first porosity. The intermediate member 30 may have a third porosity that is greater than the first porosity. The outer member 20 may have a second porosity that is greater than the third porosity.

Then, a plurality of anode members 1 are stacked. At this time, the central member 10 may be located in the center. The intermediate member 30 may include a first intermediate member 31 and a second intermediate member 32 that are positioned to face both sides of the central member 10, respectively. The outer member 20 may include a first outer member 21 and a second outer member 22 positioned against both surfaces of the middle member 30, respectively.

Then, the plurality of anode members 1 can be attached to each other by pressing the plurality of anode members 1.

Then, the electrolyte member 2 is stacked on the anode member 1. At this time, the second corner of the electrolyte member 2 may be formed to be round in plan.

Then, a shrinking process such as sintering the plurality of anode members 1 and electrolyte members 2 may be performed to form the anode 100 and the electrolyte layer 200.

When sintering a plurality of anode members 1, the outer member 20 with a large porosity may shrink more than the central member 10 with a small porosity. Therefore, the third shortest length (d3, see FIG. 3) of the outer layer 120 formed by sintering the outer member 20 is the first shortest length (d1) of the central layer 110 formed by sintering the central member 10. ) can be formed shorter than.

In addition, the second shortest length (d2, see FIG. 3) of the middle layer 130 formed by sintering the middle member 30 is shorter than the first shortest length (d1) of the middle layer 110, and the outer layer 120 It may be formed to be longer than the third shortest length (d3).

Accordingly, the corner 100a and the first corner 100b of the anode 100 may be rounded along the thickness direction Z of the anode 100.

Then, an air electrode 300 is formed on the electrolyte layer 200. At this time, the third corner 300b of the air gap 300 may be formed to be round in plan.

Although a preferred embodiment of the present invention has been described above, the present invention is not limited thereto, and can be implemented with various modifications within the scope of the claims, the detailed description of the invention, and the accompanying drawings. It is natural that it falls within the scope of the present invention.

100: fuel electrode 100a: corner of the fuel electrode
100b: first corner of fuel electrode 110: central layer
120: outer layer 130: middle layer
200: electrolyte layer 300: air electrode

Claims (12)

fuel electrode and air electrode facing each other, and
Electrolyte layer located between the fuel electrode and the air electrode
Including,
The anode has a flat shape,
The edges of the fuel electrode are rounded along the thickness direction of the fuel electrode,
The fuel electrode includes a central layer and outer layers located on both sides of the central layer,
A solid oxide cell wherein the first porosity, which is the porosity of the central layer of the fuel electrode, is smaller than the second porosity, which is the porosity of the outer layer of the fuel electrode. In paragraph 1:
A first corner, which is a corner connecting the corners of the fuel electrode, is rounded along the thickness direction of the fuel electrode. In paragraph 2,
A solid oxide cell, wherein the first corner is rounded in plan. In paragraph 3,
A solid oxide cell, wherein the edge of the fuel electrode has a radius of curvature of 1/2 the thickness of the fuel electrode and is rounded along the thickness direction of the fuel electrode. In paragraph 3,
A solid oxide cell, wherein the second corner, which is the corner of the electrolyte layer, and the third corner, which is the corner of the air electrode, are rounded in plan. In paragraph 1:
The fuel electrode further includes an intermediate layer having a third porosity and located between the central layer and the outer layer,
The third porosity is greater than the first porosity and smaller than the second porosity. In paragraph 6:
A solid oxide cell, wherein the length of the middle layer is longer than the length of the central layer and shorter than the length of the outer layer. Prepare a plurality of anode members in the shape of a plate, including a central member having a first porosity, and outer members located on both sides of the central member and having a second porosity greater than the first porosity,
Stacking and compressing the plurality of anode members,
Laminating an electrolyte member on the anode member,
Sintering the plurality of anode members and the electrolyte member to form the anode and electrolyte layer, rounding the corners of the anode along the thickness direction of the anode,
Forming an air electrode on the electrolyte layer
A method of manufacturing a solid oxide cell comprising. In paragraph 8:
By sintering the plurality of anode members,
The outer member is contracted more than the central member so that the length of the outer layer formed by sintering the outer member is shorter than the length of the central layer formed by sintering the central member. In paragraph 9:
Preparing the plurality of anode members is
A method of manufacturing a solid oxide cell, comprising forming first corners of the plurality of anode members to be rounded in a plane. In paragraph 10:
Stacking the electrolyte members
A method of manufacturing a solid oxide cell, comprising forming a second corner, which is a corner of the electrolyte member, so that it is rounded in a plane. In paragraph 11:
Forming the air gap is
A method of manufacturing a solid oxide cell, comprising forming a third corner, which is a corner of the air electrode, so that it is rounded in a plane.