KR100665391B1 - Advanced Planar Type of Solid Oxide Fuel Cells - Google Patents

Abstract

The solid oxide fuel cell of the present invention is an electrode support type or an electrolyte self-supporting unit cell in which four corner ends or two opposite surfaces are bent up or down symmetrically or asymmetrically in an "H" shape, and the inside and / or the outside thereof are linear. By having a gas channel formed in a structure or a checkered structure, the sealing effect of the reaction gas is enhanced from the “H” -shaped bent portion, and a separate gas channel structure or a separator plate without a channel support can be used, and air in a unit cell (amount The reaction gas flows well to the anode and the fuel (negative) electrode.

Solid Oxides, Fuel Cell Plates, H-Shaped, Symmetrical, Asymmetrical

Description

Advanced Planar Type of Solid Oxide Fuel Cells             

1A and 1B are schematic diagrams of a conventional SOFC unit cell having a flat plate-type self-supporting structure and a lattice arrangement type stack structure manufactured using the same.

2A and 2B are schematic diagrams showing a stack cell of four corners or two opposite sides of a conventional rectangular unit cell bent downwardly symmetrically in a “∩” shape and an internal manifold type fabricated using the same.

Figure 3a to 3b is a straight structure or checkerboard in the direction of the anode in the anode (cathode) support of the unit cell bent in the four-sided corner of the rectangular unit cell according to the invention is symmetrical (or asymmetrical) up and down in the shape of "H" It is a schematic diagram in which one quarter of the unit cell in which the reaction gas channel having the structure is formed is cut.

Figure 3c to 3d is a straight structure or checkerboard in the anode (cathode) support of the unit cell bent in a cross-section of the two opposite corners of the rectangular unit cell according to the present invention "H" shaped up and down symmetrical (or asymmetrical) It is a perspective view in which one quarter of the unit cell in which the reaction gas channel having the structure is formed is cut.

4A and 4B are schematic views for showing a form in which the bent portion of each support (fuel electrode) is surrounded by some or all of the electrolyte in the unit cell of FIG. 3.

Figures 4c and 4d shows a form in which the sealing groove for enhancing the sealing with the separating plate in the bent portion of each support (fuel electrode) in the unit cell of Figure 3 formed in a part of the corner and surround it with some or all of the electrolyte It is a schematic diagram for.

Figures 4e and 4f shows a form surrounding the part or the whole of the sealing groove for forming the sealing groove in the center of the corner for enhancing the sealing with the separation plate in the bent portion of each support (fuel pole) in the unit cell of Figure 3 It is a schematic diagram for.

Figure 5a to 5b is a straight structure or checkerboard in the direction of the anode in the cathode (anode) support of the unit cell bent in the four-sided corner of the rectangular unit cell according to the invention is symmetrical (or asymmetrical) up and down in the shape of "H" It is a schematic diagram in which one quarter of the unit cell in which the reaction gas channel having the structure is formed is cut.

Figure 5c to 5d is a cross-section of the two opposite corners of the rectangular unit cell according to the invention is a straight line toward the anode side in the cathode (anode) support of the unit cell is bent in the "H" shape up and down symmetrical (or asymmetrical) It is a schematic diagram in which one quarter of the unit cell in which the reaction gas channel having the structure or the checkered structure is formed is cut.

6A to 6B illustrate a linear structure or a checkerboard structure in the direction of a fuel electrode in an electrolyte support of a single cell in which a cross section of four corners of a rectangular unit cell according to the present invention is bent in an symmetrical (or asymmetrical) manner to an "H" shape. It is a schematic diagram in which one quarter of the unit cell in which the reactive gas channel which has is formed is cut | disconnected.

6C to 6D illustrate a straight structure in the direction of the anode in the electrolyte support of the single cell in which the end surfaces of the two opposite corners of the rectangular unit cell according to the present invention are bent upwardly and downwardly symmetrically (or asymmetrically) to an "H" shape; The first quarter of the unit cell in which the reaction gas channel having the checkered structure is formed is cut.

7A to 7B are simultaneously straight toward the anode and cathode in the anode (cathode) support of the unit cell in which the four-sided cross-sections of the rectangular unit cells according to the present invention are bent upside down symmetrically (or asymmetrically) into an "H" shape. It is a schematic diagram in which one quarter of the unit cell in which the reaction gas channel having the structure or the checkered structure is formed is cut.

7C to 7D are directions of the anode and the cathode in the anode (cathode) support of the unit cell in which the cross-sections of the two opposite edges of the rectangular unit cell according to the present invention are bent in an “H” shape up and down symmetrically (or asymmetrically). 4 quarter 1 of the unit cell in which a reaction gas channel having a linear structure or a checkered structure is formed at the same time is cut away.

FIG. 7E is asymmetrically bent upward and downward in an “H” shape having a cross-section (asymmetrically bent) in which one side section of a bent portion of a unit cell according to the present invention is not vertically symmetrical but has a cross-section rotated 90 degrees up and down. One quarter of the cell is a cutaway view.

8A to 8B are simultaneously straight toward the anode and cathode in the cathode (anode) support of the unit cell in which the four-sided cross-sections of the rectangular unit cells according to the present invention are bent upwardly and downwardly symmetrically (or asymmetrically) to the "H" shape. It is a schematic diagram in which one quarter of the unit cell in which the reaction gas channel having the structure or the checkered structure is formed is cut.

8C to 8D illustrate a fuel electrode and a cathode in a cathode (anode) support of a unit cell in which cross-sections of two opposite edges of a rectangular unit cell according to the present invention are bent in an “H” shape up and down symmetrically (or asymmetrically). Fig. 1 is a schematic diagram in which four quarters of a unit cell in which a reaction gas channel having a linear structure or a checkerboard structure is formed simultaneously in the direction thereof is formed.

9A to 9B illustrate a straight line structure or a checkerboard shape toward a fuel electrode and an air electrode in an electrolyte support of a single cell in which four corners of a corner of a rectangular unit cell according to the present invention are bent in an “H” shape up and down symmetrically (or asymmetrically). It is a schematic diagram in which one quarter of the unit cell in which the reaction gas channel having a structure is formed is cut.

9C to 9D are simultaneously linear in the direction of the anode and the cathode in the electrolyte support of the single cell in which the cross-sections of two opposite corners of the rectangular unit cell according to the present invention are bent in an symmetrical (or asymmetrical) manner to an "H" shape. It is a schematic diagram in which one quarter of the unit cell in which the reaction gas channel having the structure or the checkered structure is formed is cut.

Figure 10a is a schematic diagram showing the structure when stacked in a stack in each of the four corners of the rectangular unit cell in accordance with the present invention the cross section of the four corners of the "H" shaped up and down symmetrically or asymmetrically.

10b to 10c is a schematic diagram of a two-dimensional structure when stacked in a stack in each of the cells of the four-sided corner of the rectangular unit cell according to the present invention is bent upside down symmetrically or asymmetrically to the "H" shape 10B illustrates a case where a unit cell having a channel structure is used in only one direction of the anode side or the cathode side, and FIG. 10C is a two-dimensional schematic diagram when a unit cell having a channel structure is used in both the anode side and the cathode side.

*** Explanation of symbols on main parts of drawing ***

1: anode (cathode) 2: electrolyte 3: cathode (anode)

4: unit cell 5: sealant 6: gas channel (euro)

7: Channel support 8: Separator (A) 9: Separator (B)

10: insulation plate 11: stack 12: sealing (ash) groove

13: cathode collector 14: anode collector 15: gas manifold

31: plate portion 32: bend portion 33: support portion

34: "H" type bend 35: "H" type support

3

The present invention relates to a planar solid oxide fuel cell having an improved structure.

More specifically, the present invention is symmetrical or asymmetrical up and down the four sides of the corner end or two opposite sides of the "H" shape to maximize the effect of sealing (sealing) and electrical contact of the reaction gas during fuel cell operation The present invention relates to a solid oxide fuel cell having an electrode support type or an electrolyte support type, which is bent, and having a structure for simultaneously performing electrical contact and a gas passage (channel) therein.

In general, a fuel cell is injected with fuel gas and air into a cathode (or anode) and an anode (or cathode), causing electrochemical reactions, and conducting ion conduction through an electrolyte, and electron conduction through an external circuit. This is an energy generator that can continuously obtain electricity as long as fuel and air injection are maintained under conditions suitable for electrode and electrolyte characteristics.

Fuel cells have the advantages of high efficiency and very low pollution emissions compared to conventional power generation methods. In addition, depending on the type of electrode material and electrolyte used, the operating temperature or available fuel gas is different, so the application field belongs to various power generation devices.

The solid oxide fuel cell (SOFC) is also referred to as a ceramic fuel cell because most components such as electrode materials and electrolytes are composed of ceramics. Therefore, there is a disadvantage that can be easily broken by the external shock, but the most efficient fuel cell, but in the long run there is a very small reduction in performance.

Fuel cells, by their nature, provide a smooth flow of reactant gas to both electrode faces of a single cell (or single cell), together with electrical contact with the separator and airtightness between the two gases (air and fuel gas). It is an apparatus that induces oxygen or hydrogen ion conduction to a dense solid electrolyte layer and uses electromotive force generated by electrochemical reactions occurring in the electrode layer therefrom for power generation.

In particular, SOFC uses a metal oxide such as thermochemically stable zirconia (doped ZrO ₂ ) as an electrolyte, and a fuel electrode and an air electrode are attached thereto, and reformed fuel gas such as hydrogen, methane, propane, butane, or the like. It can be used without a reforming step, and is a high efficiency low pollution power generation method using air (or oxygen) as an oxidant.

Solid oxide fuel cell materials well known so far include a mixture of a metal such as Ni as a fuel electrode and (ZrO ₂ + 8Y ₂ O ₃ , YSZ) cermet with yttria stabilized zirconia and the like, and a zirconia (rare earth system; One or more powders of YSZ or Sc ₂ O ₃ + ZrO ₂ (ScSZ, etc.) type, ceria (CeO ₂ ) type, bismuth oxide (Bi ₂ O ₃ ) type, perovskite type, etc. By using a perovskite compound such as LaSrMnO ₃ (LSM), LaSrCoFeO ₃ (LSCF) to form a single cell composed of at least three layers.

In addition, for stack construction, Cr-5Fe-1Y ₂ O ₃ , Ni base metal, stainless steel, LaSrCrO ₃ as a current collector and a separator or an interconnector, and an electroconductive perovskite as a current collector are used. These compounds use glass or glass-ceramic as high temperature seals, which are stacked together to form a stack, and combined with other peripherals such as reformers and power converters to form the entire power generation system. .

The unit cell, which is the core component of the fuel cell stack, is formed by attaching a fuel electrode (cathode) on one side and an air electrode (anode) on the other side with an electrolyte interposed therebetween. In the intermediate layer corresponding to the electrolyte, the fuel gas and the oxidizing gas have a compact structure that does not vent each other.

In general, tube type and plate type are mainly developed in SOFC according to the type of unit cell, but double tube type was developed first, but the manufacturing method was difficult, which made it difficult to practically use.

Meanwhile, as shown in FIG. 1A of the accompanying drawings, in the flat plate type, the separator gas 8 is generally used to separate the fuel gas and the oxidizing gas and supply the same to the unit cell 4. ) Must have low electrical resistance because the generated electricity must flow well.

In addition, as shown in FIG. 1B, when manufacturing a stack, a plate-shaped unit cell is placed between the separator plates, and airtightness is sealed using a sealing material or a sealing glass so that two gases flowing along both channels of the separator plate do not mix with each other. At the same time, smooth gas supply should be provided at both electrode layers of the unit cell.

In particular, in the remaining part where the unit cell 4 and the separator 8 are not in contact, gas sealing should be performed in the form of an insulating layer or plate made of a material having airtightness and insulating properties, for example, ceramics-glass.

Metal and ceramic materials are widely used as materials for such a separator, and should be a dense material that has good electrical conductivity and maintains gas tightness, and is a high temperature, for example, 400 to 1000 ° C., of an operating temperature of a solid oxide fuel cell. Should have oxidation resistance.

The reason for this is that as shown in the stack of Fig. 1A or 1B, hydrogen as fuel gas is disposed on the anode side of the unit cell (upper side in the separator plate), and air as oxidant is separated from the cathode side of the unit cell (bottom side in the separator plate). In this way, each reaction gas is separated and supplied to the unit cell, and at the same time, the electricity flows well in the vertical direction of the stack, so the performance loss due to the internal resistance of the stack should be small.

Therefore, the use of metal separation plates rather than ceramic materials, which are difficult to process and expensive to manufacture, is an advantageous technique for commercializing SOFC power generation systems. However, the higher the temperature or the longer the operation time, the more the surface of the cathode side of the metal separator plate has an adverse effect of shortening its lifespan in terms of durability as the internal resistance of the stack increases as the metal oxidation progresses. .

In recent years, SOFC technology has been able to achieve the same performance at lower temperatures (medium temperature) with the development of better performance cells. Therefore, the use of metal separators, which are cheaper than ceramics, is frequently used.

In addition, unlike the ceramic material, the metal separator plate has an advantage of being easily manufactured in various forms, and thus is being widely used when developing an SOFC stack having an intermediate temperature (about 500 to 850 ° C). However, the disadvantage of short stack life due to oxidation of the surface of the metal separator plate at high temperatures is still a problem to be solved.

In addition, the metal separator has a value 1.2 to 2 times larger than the thermal expansion coefficient of the unit cell (typically about 10 × 10 ^-6 / ° C) at the temperature at which the SOFC operates. There is a disadvantage in that a change in temperature (i.e. heat cycle) from high temperature to high temperature, or from high temperature to room temperature, results in greater thermal stress.

On the other hand, the original use of metal or ceramics or separator plate is in electrical contact with the gas flow, and the channel structure must always be provided for the smooth flow of the injected reaction gas. In particular, in the case of the metal separator, the manufacturing process is focused on machining rather than press molding. Therefore, it takes a lot of manufacturing time and cost to process the gas channel, which is an essential structure in the fuel cell. Increase the manufacturing cost of the entire SOFC stack.

2 of the accompanying drawings is a single cell (Fig. 2a) and four corners of the conventional (prescribed by the present inventor) or two opposite sides of the rectangular battery unit bent downward in a "∩" shape and manufactured using the same Fig. 2b shows a stack configuration of the internal manifold type.

As in the unit cell and stack configuration of FIG. 2, the channel support 7 is mounted between the grooves in which the gas channel 6 is formed on the separator plate 8, the unit cells 4 are coupled, and the unit cells 4 are connected. And the separator 9 through the seal groove 12, sealing with a porous insulating plate 10, i.e., ceramic insulating felt and sealing glass, to simplify the sealing area and relieve thermal stress. Then, the fuel cell stack was manufactured by continuously connecting in this order and stacking cells and components vertically in accordance with the required voltage (power amount).

Therefore, in the conventional example of FIG. 2, the sealing material can be inserted with a free space (sealing groove) in a form in which the gas sealing part is absolutely separated from the case of using the simple flat plate cell as shown in FIG. The improved sealing condition can be obtained, in which case the sealing function can be improved, so that the entire stack can be heated and cooled again and used as a thermal cycle.

However, when manufacturing the stack as shown in FIG. 2B using the unit cell of FIG. 2A, the channel structures of the channel support 7 and the separator 8 must be additionally mounted.

In particular, in the stack assembly diagram of FIG. 2A, the channel structure of the separator plate 8 must be simultaneously formed on the upper and lower surfaces of the separator plate 8 so that fuel gas flows smoothly in the anode of the unit cell 4 and air flows smoothly in the cathode. . However, the channel structure of the separator 8 increases the manufacturing cost of the separator 8 and has a disadvantage of increasing the manufacturing cost of the SOFC stack.

In addition, the bent portion of the unit cell of FIG. 2A may be gas sealed only for the anode (downward), and gas sealing efficiency is not considered for the cathode (upward), which causes a problem in that gas sealing efficiency is lowered.

The present invention has been made to solve the problems of the prior art as described above, another object of the present invention is to form the shape of the SOFC unit cell symmetrically upward or downward on the four sides of the edge end or two opposite sides of the "H" shape. Or it can be asymmetrically bent to enhance the gas sealing effect on the fuel electrode or air electrode side of the stack plate during the stack fabrication, and at the same time to have a channel structure to reduce the thickness of the separator plate without the need to process the gas channel separately on the separator plate. There is provided an improved structure of a planar solid oxide fuel cell.

Another object of the present invention is to provide a flat solid oxide fuel cell having an improved structure that can be used to economically inexpensive separator because there is no need to manufacture the anode or the channel of the cathode in the shape of the unit cell when manufacturing the SOFC stack. It is.

It is still another object of the present invention to provide a flat solid oxide fuel cell having an improved structure capable of manufacturing a stack having a higher output and durability in the same stack size as in the prior art when manufacturing an SOFC stack.

It is still another object of the present invention to improve the lifespan of a unit cell by improving high temperature creep resistance at an anode or a cathode having a channel corresponding to the long-term performance of the unit cell. To provide.

One embodiment of the present invention for achieving the above object is, in a single cell of a solid oxide fuel cell consisting of a fuel electrode (cathode), an electrolyte, an air electrode (anode), the four sides or two opposite edges of the unit cell The end of the surface is bent up and down symmetrically or asymmetrically to form a bent portion of the "H" shape, characterized in that the gas channel is formed on the lower side and / or the upper side of the unit cell.

In addition, in the unit cell, an electrolyte is coated on the entire upper surface of the flat plate portion, the end portion of which is bent vertically symmetrically or asymmetrically, and all or a portion of the bent portion and the support portion, and the porous portion is coated on the electrolyte. Porous anode (cathode) support composed of triple or multi-layered membranes coated with cathode (anode), characterized in that the gas channel is formed on the lower side and / or the upper side of the plate-shaped solid Oxide fuel cell.

In addition, in the unit cell, the electrolyte is densely coated on the entire upper surface of the flat plate portion, the end portion of which is bent vertically and symmetrically or asymmetrically, and all or a portion of the bent portion and the support portion, and the cathode is formed on the upper portion of the electrolyte. An electrolyte support type composed of a triple film or a multilayer film coated with an anode), and has a gas channel structure inside and / or outside thereof.

In addition, one side surface of the bent portion forms a step shape to form a sealing groove.

In addition, the upper end surface of the bent portion forms an uneven shape to form a sealing groove.

In addition, the bent portion is formed only on each of the two upper and lower surfaces in a cross-section in which one side surface of the bent portion is rotated 90 degrees, not the upper and lower symmetry, the upper and lower sides of the two-sided bending.

In addition, the unit cell has a gas channel in the fuel electrode (cathode) support unit cell at the same time or in one direction toward the anode and the cathode, and it is preferable that they are formed in a linear structure or a checkerboard structure.

In addition, the cross-sectional structure of the linear structure or the checkered structure of the gas channel formed in the bent portion and the anode (cathode) support of the up and down symmetrical or asymmetrical of the present invention, the trapezoidal or rectangular with the right angled protrusion is obtuse and acute It is characterized in that the protrusion has a part serving as a gas passage (channel) in a complex form combined with a circular protrusion.

In the present invention, Figure 3 is a reaction gas channel in the support of the unit cell is bent in the symmetrical (or asymmetrical) up-down symmetrical (or asymmetrical) in the "H" shape of the cross section of the four sides or opposite sides of the rectangular unit cell according to the invention The schematic diagram of this formed unit cell is shown. 3A shows a fuel cell (cathode) support unit cell in which four surfaces are bent upside down symmetrically (or asymmetrically) in an "H" shape, and a reaction gas channel is formed in a straight structure at the fuel electrode (cathode) support. . FIG. 3B is a fuel cell (cathode) support unit cell in which four surfaces are symmetrically (or asymmetrically) bent, and the reaction gas channel is formed in a checkerboard structure in the fuel cell (cathode) support. FIG. 3C illustrates a fuel cell (cathode) support unit cell in which two opposite surfaces are bent in an “H” shape up and down symmetrically (or asymmetrically), in which reaction gas channels are formed in a straight structure in the anode support. FIG. 3D illustrates an anode (cathode) support unit cell in which two opposite surfaces are bent in an symmetrical (or asymmetrical) manner in an “H” shape, and a reaction gas channel is formed in a checkerboard structure in the anode support. Formed.

4 is a two-dimensional cross-sectional schematic diagram of the bent portion in each of the unit cells of FIG. 3, FIG. 4A surrounds the entire "H" -shaped bent portion of the support, and FIG. 4B shows a portion of the "H" -shaped bent portion of the support. It is a schematic diagram in the case surrounded by. 4c and d are sealing grooves at the corners of the “H” -shaped bent portion of the support, and FIGS. 4e and f are schematic views of the seal grooves at the central portion at the corners of the “H” -shaped bent portion of the support.

5 is a reaction gas channel formed in a cathode support of a unit cell in which a cross section of four corners or two opposite sides of a rectangular unit cell according to the present invention is bent upwardly and downwardly symmetrically (or asymmetrically) into an "H" shape. 5A is a cathode (anode) support unit cell in which four-sided cross sections are bent upside down symmetrically (or asymmetrically) in an "H" shape to form a reaction gas channel in a linear structure. FIG. 5B is a bent cathode (anode) support unit cell in which four surfaces are symmetrically (or asymmetrically) up and down, and a unit cell in which a reaction gas channel is formed in a checkered structure, and FIG. 5C Is a cathode (anode) support unit cell which is bent in a symmetrical (or asymmetrical) manner up and down in an "H" shape with two opposite faces, and is a unit cell in which a reaction gas channel is formed in a linear structure. 5d is jiyida unit cells in the reaction gas channel to the grid-like structure is formed as an air electrode (anode) with a cross-section of the second surface opposite to the uplink and downlink are bent symmetrically (or asymmetric) to the "H" shaped support type single cell.

6 is a cross-sectional view of four corners or two opposite surfaces of a rectangular unit cell according to the present invention in which a reaction gas channel is present in an electrolyte of a unit cell in which the cross-sections of the “H” shape are bent up and down symmetrically (or asymmetrically). As a schematic diagram of a unit cell, FIG. 6A is an electrolyte support unit cell in which four-sided cross sections are bent symmetrically (or asymmetrically) in an “H” shape, in which a reaction gas channel is formed in a linear structure on an electrolyte support. 6B is an electrolyte support unit cell in which four-sided cross sections are bent in an symmetrical (or asymmetrical) manner in a "H" shape, wherein the reaction gas channel is formed in a checkerboard structure in the electrolyte support. 6C is an electrolyte support unit cell in which two opposite surfaces are bent in an “H” shape up and down symmetrically (or asymmetrically), and the reaction gas channel is straight on the electrolyte support. FIG. 6D is an electrolyte support unit cell in which two opposite surfaces are bent up and down symmetrically (or asymmetrically) in an “H” shape, and a reaction gas channel is formed on the electrolyte support. It is a unit cell formed in a structure.

7 is a reaction gas channel formed on a support of a single cell in which the cross-sections of the four corners or two opposite surfaces of the rectangular unit cell according to the present invention are bent upwardly and downwardly symmetrically (or asymmetrically) in an “H” shape. A schematic diagram of a unit cell is shown. 7A shows a fuel cell (cathode) support unit cell in which four surfaces are bent up and down symmetrically (or asymmetrically) in an "H" shape, and reactant gas simultaneously in both directions of a fuel electrode (cathode) support side and an air electrode side. The channel is formed in a straight structure. FIG. 7B is a fuel cell (cathode) support unit cell in which four surfaces are symmetrically (or asymmetrically) bent up and down, and a reaction gas channel is formed in a checkerboard structure simultaneously in both directions of the anode (cathode) support side and the air electrode side. It is. FIG. 7C is a fuel cell (cathode) support unit cell in which two opposite surfaces are bent in an symmetrical (or asymmetrical) manner in an "H" shape, and is a reaction gas channel simultaneously in both directions of the anode support side and the cathode side. It is formed in this linear structure. FIG. 7D is a fuel cell (cathode) support unit cell in which two opposite sections are bent in an symmetrical (or asymmetrical) manner in an "H" shape and simultaneously in both directions of the anode (cathode) support side and the cathode side. The reaction gas channel is formed in a checkered structure. FIG. 7E is asymmetrically bent upward and downward in an “H” shape having a cross section in which one side section of the bent portion of the unit cell according to the present invention is rotated 90 degrees up and down instead of vertically symmetrical; It is a schematic diagram in which a reaction gas channel is formed in a linear structure simultaneously in both directions of the anode support side and the cathode side as a single unit cell.

FIG. 8 is a cathode support unit cell having four corners or two opposite surfaces of a rectangular unit cell bent in an “H” shape up and down symmetrically (or asymmetrically). 8A is a schematic diagram of a unit cell in which reaction gas channels are formed simultaneously in both directions, and FIG. 8A shows an air cathode (anode) support type in which the cross-sections of the four surfaces are bent upwardly and downwardly symmetrically (or asymmetrically) in an "H" shape. The unit cell is a unit cell in which a reaction gas channel is formed simultaneously in both the cathode support side and the fuel electrode side in a straight structure, and FIG. 8B shows a cathode having a curved surface formed on the four surfaces thereof in a symmetrical (or asymmetrical) manner. As a support unit cell, the reaction gas channel is formed in a checkerboard structure simultaneously in both the cathode support side and the fuel electrode side, and FIG. 8C is a cross-section of two opposite surfaces. It is a cathode (anode) support unit cell which is bent symmetrically (or asymmetrically) in the shape of "H" and is a unit cell in which reaction gas channels are formed in a straight structure simultaneously in both directions of the cathode support side and the fuel electrode side. FIG. 8D is a cathode (anode) support unit cell in which two opposite sections are bent in an symmetrical (or asymmetrical) manner in an "H" shape and is checkered simultaneously in both directions of the cathode support side and the anode side. It is a unit cell in which a reaction gas channel is formed in a structure.

FIG. 9 is a cross-sectional view of four corners or two opposite surfaces of a rectangular unit cell according to the present invention in which a reaction gas channel is present in an electrolyte of a unit cell in which an “H” shape is bent upward and downward symmetrically (or asymmetrically). As a schematic diagram of a unit cell, FIG. 9A is an electrolyte support unit cell in which the cross-sections of the four surfaces are bent upwardly and downwardly symmetrically (or asymmetrically) in an “H” shape. FIG. 9B is an electrolyte support unit cell in which a cross-section of four surfaces is bent up and down symmetrically (or asymmetrically) in an “H” shape with a gas channel formed in a linear structure. The reaction gas channel is formed in a checkerboard structure at the same time in both directions toward the cathode side, and FIG. 9C shows a cross-section of two opposite surfaces having an "H" shape and up-down symmetrically (or asymmetrically). A bent electrolyte support unit cell, in which a reaction gas channel is formed in a straight line structure at both sides of a fuel electrode side and an air electrode side in an electrolyte support, and FIG. 9D shows an "H" shaped cross section of two opposite surfaces. An electrolyte support unit cell that is bent upside down symmetrically (or asymmetrically) is a unit cell in which a reaction gas channel is formed in a checkerboard structure simultaneously in both directions of a fuel electrode side and an air electrode side.

Figure 10a is a schematic diagram showing the structure when stacked in a stack in each of the four corners of the rectangular unit cell in accordance with the present invention the cross section of the four corners of the "H" shaped up and down symmetrically or asymmetrically. Among them, 10b to 10c are two-dimensional structures when stacked in stacks in each unit cell in which the four-sided cross-sections of the rectangular unit cells according to the present invention are bent upside down symmetrically or asymmetrically in an "H" shape. 10b is a case where a unit cell having a channel structure is used only in one direction of the anode side or the cathode side, and FIG. 10c is a two-dimensional schematic diagram when a unit cell having a channel structure is used in both the anode side and the cathode side.

Hereinafter, the present invention will be described in detail so that those skilled in the art to which the present invention pertains can easily carry out the present invention. The preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Let's explain. Other objects, features, including effects, effects of the present invention will become more apparent from the description of the preferred embodiment.

The present invention will be described in more detail with reference to Examples.

Example 1 A fuel cell (cathode) support unit cell having a reactive gas channel having four corners or two opposite surfaces having a "H" shape, which is bent up and down symmetrically or asymmetrically.

The conventional bent type cell is a channel used in the present invention, while the end surface of the flat end portion 4 or two opposite faces of the flat plate 31 are bent downward in a “∩” shape, as shown in FIG. 2A. As shown in FIG. 3A, the bent unit cell 4 having the structure is bent upwardly and downwardly symmetrically or asymmetrically as the cross-sections of four edges or two opposite surfaces of the flat plate 31 are "H". Refers to a unit cell having a bent portion 34 in a shape and at the same time having a relatively thick fuel electrode 1 support having a channel 6 which facilitates the flow of reaction gas in the direction of the anode side and / or in the air side. .

The unit cell 4 is formed by a symmetrical or asymmetrically formed bent portion 34 and a support 35 with a porous fuel electrode (cathode 1) having a thickness of about 1 to 2 mm and a dense thin film having a thickness of 5 to 50 μm. (35) The electrolyte (2) is coated on the upper surface and the entire corner, and the porous cathode (anode, 3) is coated on the upper surface of the electrolyte (2), and the electrolyte (2) at the center and the anode (cathode, at the bottom) are coated. 1), The upper part is a triple film single cell comprised of a cathode (anode, 3).

At this time, the final unit cell may be manufactured in the form as shown in Figure 3a, 3b, 3c and 3d, for example, the size is about 100 × 100mm, the thickness is about 1.7mm, each bent upward and downward The height of the corner portion is about 3.5mm, the inner height is about 1.8mm, and the width of the bent portion in the width direction is about 3mm.

The final unit cell can also be manufactured in the form as shown in FIGS. 7A, 7B, 7C and 7D and facilitates the flow of reaction gas in the direction of the anode side and / or the air side on a relatively thick anode support. It can be made into a unit cell having a channel.

These production methods are zirconia (ZrO ₂ ), ceria (CeO ₂ ), bismuth oxide using one of the known slurry coating method, chemical vapor deposition method, tape casting method, screen printing, etc. on the anode support which is the primary sintered body. After coating one or more of the (Bi ₂ O ₃ ) -based, lanthanum-based perovskite-based electrolyte, and repeated heat treatment at about 1250 ℃ 1 to several times, finally 1450 ℃ to 1600 ℃ Sintering at to prepare a dense electrolyte layer having a thickness of about 5 to 50㎛.

Here, as shown in FIG. 4A, the entire bent portion can be surrounded by a dense electrolyte layer, and as shown in FIG. 4B, the dense electrolyte 2 layer is surrounded by the upper end surface of the anode support 1 and the support bent portion 34. It is possible to coat the edge side of the shell, which can prevent the leakage of fuel gas directly from the porous support during SOFC operation, and can also increase the sealing effect. In addition, by forming the sealing groove 12 in the support 35 can be manufactured as shown in Figures 4c, 4d and 4e, 4f, it can be manufactured in the form as shown in Figure 10a using these unit cells. As shown in FIG. 4C, the sealing groove 12 has one side surface of the bent portion 35 formed in a stepped shape, or the bent portion 35 as shown in FIG. 4D. The upper end surface of is formed in the uneven | corrugated shape.

In addition, each of the bent portion and the channel structure, for example, straight or checkered may be modified in various forms. That is, it may be a ladder type that is a combination of an obtuse angle or an acute angle rather than a simple rectangular structure in a straight structure, and the shape of the protrusion may be manufactured in various shapes such as a square or a circle in a checkered structure. In this case, the same channel structure can be obtained even when the straight line and the checkerboard channel structure or the equivalent channel structure are merged.

On the upper surface of the electrolyte 2 layer, LSM (La _0.85 Sr _0.15 MnO ₃ ) + YSZ or LSCF (La _0.8 Sr _0.2 Co _0.6 Fe _0.4 O ₃ ) + CG (S) O composition containing 20% graphite powder Screen-print the cathode (anode, 3) using a paste of powder, dry it, and heat-treat it at 1,100 ° C. Finally, as shown in FIGS. 3A, 3B, 3C, and 3D and 7A, 7B, 7C and 7D, A SOFC unit cell having a fuel electrode (cathode) support type structure having the same three-layer structure can be manufactured.

It is important to fabricate each unit cell to have the same size for stack fabrication assembly. The size and height of the bent part 34 may be reprocessed according to a method of contacting and sealing each unit cell with a separator. In particular, when the cells are connected in a lattice-array manner, to form one layer of the stack as shown in FIG. 1 (b), the thickness of each unit cell and the height of the bent portion 34 should be the same size. do.

In this embodiment, when the size of the final unit cell is about 100 × 100 mm, the height of the support part 35, which is the bent corner portion, is about 3.5 mm, and the inner height is about 1.8 mm. It was about 1mm, and these conditions depended on the size of the press mold and the heat treatment or sintering temperature when manufacturing the unit cell.

The unit cell according to the present invention maintains a constant gas distribution of the inner channel, and uses a current collector layer and a current collector to make electrical contact. In addition, it is easy to make contact with the separator using a porous metal sheet (felt) and a mesh (mesh).

Example 2 A cathode (anode) support unit cell having a reactive gas channel with four corners or two opposite surfaces having a "H" shape, which is bent upward or downward symmetrically or asymmetrically

First, spherical graphite powder was added to a powder of LSM (La _0.85 Sr _0.15 MnO ₃ ) + YSZ or LSCF (La _0.8 Sr _0.2 Co _0.6 Fe _0.4 O ₃ ) + CG (S) O to prepare a cathode (anode) support. After mixing, it was known press molding and heat treatment conditions to finally prepare a porous cathode (anode) support of about 40%.

This cathode (anode) support is manufactured in the form as shown in Figures 5a, 5b, 5c and 5d, the size is about 100 × 100mm, thickness is about 1.7mm, the height of the corner portion bent upward and downward is about 3.5mm The inner height was about 1.8 mm, and the bend portion had a thickness in the width direction of about 3 mm.

NiD powder and 8YSZ (ZrO ₂ + 8 mol% Y ₂ O ₃ ) were formed on the lower surface of the cathode (anode) supporter 3 with a dense electrolyte layer 2 formed on the lower surface of the cathode (cathode). ) By using the same printing method as in Example 1 as a starting material using a powder mixture of about 50:50 in a weight ratio and 20% of graphite powder, as shown in FIGS. 5A, 5B, 5C and 5D. A SOFC unit cell having a positive electrode support type structure was manufactured.

Particularly, the reaction gas channel may be a straight structure or a checkerboard structure as in FIGS. 5A, 5B, 5C, and 5D, but the channel structure may be a ladder type that is a combination of an obtuse angle or an acute angle rather than a simple rectangular structure in the linear structure. And the shape of the protrusion in the checkered structure can be produced in various forms such as square, round. In addition, as shown in FIGS. 8A, 8B, 8C, and 8D, the reaction gas channel structure is formed in the air electrode side direction and / or the fuel electrode side direction to facilitate the flow of the reaction gas. Even when the straight and checkered channel structures or equivalent channel structures are merged, the same effect can be obtained. As a result, they can be determined depending on the shape or processing of the press die during molding. The following content is the same as that of Example 1.

Example 3 Electrolyte-supported unit cell having a reaction gas channel with four corners or two opposite surfaces having a "H" shape , bent up and down symmetrically or asymmetrically

In preparing an electrolyte support type or a self-supporting unit cell, one or more solid oxides of zirconia (ZrO ₂ ), ceria (CeO ₂ ), bismuth oxide (Bi ₂ O ₃ ) and perovskite based The electrolyte raw material powder is granulated to a size of 10 to 100 μm, and then used to form the same as in FIGS. 6A, 6B, 6C, and 6D and 9A, 9B, 9C, and 9D, followed by sintering. Finally, the electrolyte plate 2 having a size of about 100 x 100 mm, a thickness of about 1 mm or less, an inner height of the bent corners symmetrically or asymmetrically up to about 2 mm, and a thickness of about 3 to 4 mm is obtained. To make.

At this time, the width and depth of the bone are molded between about 1 and 0.8 mm, respectively, depending on the shape of the press mold when forming the raw powder, which has a channel having a linear structure as shown in FIGS. 6A and 6C and 9B and 9D. 6b and 6d and as shown in 9b and 9d it can be manufactured in a structure having a channel in a checkerboard structure. As mentioned above, such a channel structure may be a ladder, which is a combination of an obtuse angle or an acute angle rather than a simple rectangular structure in the linear structure, and the protrusions of the checkered structure may be manufactured in various shapes such as squares and circles. The same effect is obtained when the channel structure of the type channel structure or the equivalent shape is merged.

Herein, a cathode paste is prepared using a NiO powder, which is a cathode component manufactured by a conventional method, and a powder of about 50:50 mixed with 8YSZ (ZrO ₂ + 8 mol% Y ₂ O ₃ ) in a weight ratio and 20% graphite powder as a starting material. do. This was printed or coated on the bottom surface of the plate 2 of the prepared electrolyte, in particular, the floor or valley of the reaction gas channel, and then dried and heat-treated at a temperature of 1300 to 1450 ° C. to form the fuel electrode 1. As in Example 1, a paste of LSM (La _0.8 Sr _0.2 MnO ₃ ) + YSZ or LSCF (La _0.8 Sr _0.2 Co _0.6 Fe _0.4 O ₃ ) + CG (S) O, which is a cathode material, was printed and dried, and then dried at 1100 ° C. An SOFC unit cell having an electrolyte support type or a self-supporting structure having a channel structure was prepared by heat treatment in and out. As in Examples 1 and 2 below. 3 is an air electrode.

The fuel cell of the present invention has the advantage of reducing the thickness and cost of the separator by simplifying the channel structure on the separator when stacking. Therefore, more single cells can be stacked in a stack of relatively the same size, and thus a larger output can be obtained. This is especially true in the case of single cell manufacture in which the cross-sections of the four corner ends or opposite two surfaces are bent upside down symmetrically or asymmetrically in an "H" shape as in FIGS. 4C, 4D, 4E and 4F (eg For example, by forming (press molding) the portions corresponding to the cathodes, the electrolytes, and the anodes so as to include the channels, the channels through which the fuel and the air reactant gas flow do not have to be processed separately in the separator.

The flat solid oxide fuel cell stack of the improved structure manufactured by stacking the unit cells formed as described above is provided with the cathode current collector 13 positioned on the unit cell 4 as shown in FIGS. 10A to 10C. After placing a thin separator plate 8 above the cathode current collector 13, placing the anode current collector 14 on the separator plate 8, and mounting the unit cell 4 again. Both sides of the fuel electrode 1 and the air electrode 3 can be sealed by sealing using the “H” -shaped bent portion 35 and / or the stepped sealing groove 12 or the uneven sealing groove 12. have.

Therefore, as described above, the unit cell structure of the present invention can enhance the sealing function and impact strength by allowing the bent portion to be simultaneously formed on the upper and lower surfaces in the form of "H" rather than the unit cell bent downward in a "∩" shape. It is effective.

In other words, to maximize the effect of sealing (sealing) and electrical contact of the reaction gas during operation of the fuel cell, such as in a single cell, the four sides or two opposite sides of the edge end are "H" shaped up and down symmetrically or asymmetrically. If the structure is bent at the same time and the channel structure is made from the unit cell manufacturing molding, if a simple plate-shaped separator having no channel structure of the anode or cathode is used as it is in the stack production, a relatively inexpensive separator may be used for stack production. It is possible to enhance the sealing effect to prevent each reaction gas from leaking.

In addition, the present invention has the effect of manufacturing a low-cost SOFC stack to compensate for the high manufacturing cost of the separator, which is a difficult problem in the previous SOFC development.                     

In addition, the present invention can reduce the price of the SOFC stack by improving the overall shape of the unit, and also reduce the size and weight of the relatively expensive separator plate, thereby reducing the size and weight of the entire stack, ultimately life and durability This improves the ease of operating conditions.

The embodiments disclosed herein are only presented by selecting the most preferred examples to help those skilled in the art from the various possible examples, the technical spirit of the present invention is not necessarily limited or limited only by this embodiment, Various changes and modifications are possible within the scope without departing from the technical spirit of the invention, as well as other embodiments that are equally possible.

Claims (21)

In a unit cell of a solid oxide fuel cell composed of a fuel electrode (cathode), an electrolyte, and an air electrode (anode), The edges of the four sides of the unit or two opposite sides are bent upside down symmetrically or asymmetrically to form a bent portion of the "H" shape, and a gas channel is formed on the lower side or the upper side of the unit cell. Flat solid oxide fuel cell having an improved structure, characterized in that. The method of claim 1, wherein the unit cell is coated with an electrolyte on the entire upper surface of the plate portion, the bent portion and the support portion, the end portion is bent vertically vertically symmetrically or asymmetrically, the electrolyte is coated Porous anode (cathode) support composed of triple or multi-layered membranes coated with porous cathode (anode) on the upper side of the flat plate type with improved structure, characterized in that gas channel is formed on its lower or upper side Solid oxide fuel cell. According to claim 1, One side cross section of the bent portion, Flat solid oxide fuel cell having an improved structure characterized in that forming a step for forming a sealing groove. According to claim 1, wherein the upper end surface of the bent portion, Flat solid oxide fuel cell having an improved structure characterized in that to form a groove for sealing by forming an uneven shape. 3. The improved flat plate type of claim 2, wherein the anode support unit cell has gas channels simultaneously or in one direction toward the anode and the cathode, and is formed in a linear structure or a checkerboard structure. Solid oxide fuel cell. According to claim 2 or claim 3, wherein the cross-sectional structure of the straight structure or checkerboard structure of the gas channel formed in the bent portion and the anode (cathode) support formed up and down symmetrically or asymmetrically has a right angled projection at an obtuse angle and an acute angle An improved planar solid oxide fuel cell, characterized in that the trapezoidal shape or a rectangular protrusion has a portion serving as a gas passage (channel) in a complex form combined with a circular protrusion. The method of claim 1, wherein the unit cell, An electrolyte is densely coated on the entire upper surface of the flat plate portion, the lower portion of which is vertically bent symmetrically or asymmetrically, and all or a portion of the bent portion and the support portion, and a porous anode (cathode) A porous cathode (anode) support type consisting of a triple film or a multilayer film coated with) and having a gas channel formed inside or outside thereof. The method of claim 7, wherein one side cross section of the bent portion, Flat solid oxide fuel cell having an improved structure characterized in that forming a step for forming a sealing groove. The method of claim 7, wherein the upper end surface of the bent portion, Flat solid oxide fuel cell having an improved structure characterized in that to form a groove for sealing by forming an uneven shape. 8. An improved flat plate according to claim 7, wherein said cathode (anode) support type unit cell has gas channels simultaneously or in one direction toward the anode and the cathode, and is formed in a linear structure or a checkerboard structure. Solid oxide fuel cell. The cross-sectional structure of the straight line structure or the checkerboard structure portion of the bent portion and the gas channel formed in the anode (cathode) support, wherein the bent portion formed up and down symmetrically or asymmetrically has an obtuse angle and an acute angle. Flat trapezoidal fuel cell of the improved structure, characterized in that the trapezoidal shape consisting of a rectangular protrusion or a combination of circular protrusions having a portion serving as a gas passage (channel). The method of claim 1, wherein the unit cell is densely covered with an electrolyte on the entire upper surface of the plate portion and the bent portion and the support portion of the flat plate, the terminal portion is bent vertically vertically symmetrically or asymmetrically, and the upper portion of the electrolyte An electrolyte support type comprising a triple membrane or multiple membranes coated with an air electrode (anode), and having a gas channel structure inside or outside thereof, the planar solid oxide fuel cell having an improved structure. The method of claim 12, wherein one side cross section of the bent portion, Flat solid oxide fuel cell having an improved structure characterized in that forming a step for forming a sealing groove. The method of claim 12, wherein the upper end surface of the bent portion, Flat solid oxide fuel cell having an improved structure characterized in that to form a groove for sealing by forming an uneven shape. 13. The planar solid oxide of claim 12, wherein the electrolyte supporting unit cell has gas channels simultaneously or in one direction toward the anode and the cathode, and they are formed in a linear structure or a checkerboard structure. Fuel cell. 16. The cross-sectional structure of a straight line structure or a checkerboard structure portion of the bent portion and the gas channel formed in the anode (cathode) support, wherein the vertically symmetrical or asymmetrically formed bent portion has a right angle and an obtuse angle. Flat trapezoidal fuel cell of the improved structure, characterized in that the trapezoidal shape consisting of a rectangular protrusion or a combination of circular protrusions having a portion serving as a gas passage (channel). The said edge terminal 4 surface or opposing one of Claims 1, 2, 3, 4, 5, 7, 8, 9 and 10. Zirconia (ZrO ₂ ), ceria (CeO ₂ ), bismuth oxide (Bi ₂ O ₃ ), lanthanum-based perovskite Coating one or more electrolytes in the system and heat-treating them to prepare a dense electrolyte layer having a thickness of 5 to 50 µm, and coating an air electrode (anode) on the electrolyte-coated upper part or a fuel electrode (cathode) on the lower part of the electrolyte-coated Flat type solid oxide fuel cell having an improved structure, characterized in that the support type consisting of a triple or multi-layer coated with a). The zirconia (ZrO ₂ ) type, ceria (CeO ₂ ) type, bismuth oxide (Bi ₂ O ₃ ) type, or lanthanum type perovskite type according to any one of claims 12 to 15. An electrolyte plate having a thickness of 50 to 2000 μm was formed by using one or more solid oxide electrolyte raw materials and granulated powder having a size of 10 to 100 μm. A flat type solid oxide fuel cell having an improved structure, characterized in that it is an electrolyte support type consisting of a triple membrane or a multilayer membrane as a unit cell coated with a fuel electrode at a lower part of the part and an anode at an upper part of the electrolyte. In a solid oxide fuel cell stack, A first unit cell having an “H” shaped bent portion formed by bending an end portion of four corners or two opposite surfaces upside down symmetrically or asymmetrically; A cathode current collector positioned on the first unit cell; A separator having a thin thickness disposed on the cathode current collector; An anode current collector positioned on the separator; And A first unit cell having an “H” shaped bent portion formed by bending an end portion of four corners or two opposite surfaces positioned on the anode current collector upside down symmetrically or asymmetrically; The flat type solid oxide fuel cell stack having an improved structure formed by sealing both sides of the anode (1) and the cathode (3) by using the bent portion. The method of claim 19, wherein one side cross section of the bent portion, An improved flat plate solid oxide fuel cell stack, characterized in that to form a step for forming a sealing groove. The method of claim 19, wherein the upper end surface of the bent portion, An improved flat plate type solid oxide fuel cell stack, characterized in that to form an uneven shape to form a groove for sealing.

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