KR20190028340A - Solid oxide fuel cell and a battery module comprising the same - Google Patents

Abstract

The present invention relates to a solid oxide fuel cell and a battery module including the same as a unit cell. The solid oxide fuel cell comprises: a unit cell including an anode, an electrolyte layer, and a cathode; a cathode current collector provided on the cathode side of the unit cell; and a cathode functional current collecting layer provided on the opposite side of the surface on which the unit cell of the cathode current collector is provided. The cathode functional current collecting layer comprises lanthanum strontium cobalt oxide (LSC), and the porosity of the cathode functional current collecting layer is 10% or more and 90% or less. Performance improvement can be achieved by introducing a cathode functional current collecting layer to ensure sufficient electrical conductivity and increasing a three-phase boundary (TPB).

Description

SOLID OXIDE FUEL CELL AND A BATTERY MODULE COMPRISING THE SAME [0002]

The present application claims the benefit of the filing date of U.S. Patent Application No. 10-2017-0115328, filed on September 8, 2017, to the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference.

The present invention relates to solid oxide fuel cells and battery modules comprising the same.

Recently, as the exhaustion of existing energy resources such as oil and coal is predicted, interest in energy that can replace them is increasing. As one of such alternative energies, fuel cells have attracted particular attention due to their advantages such as high efficiency, no emission of pollutants such as NOx and SOx, and abundant fuel.

A fuel cell is a power generation system that converts the chemical reaction energy of a fuel and an oxidant into electric energy. Hydrogen, hydrocarbons such as methanol and butane are used as fuel, and oxygen is used as an oxidant.

BACKGROUND ART Fuel cells include a polymer electrolyte fuel cell (PEMFC), a direct methanol fuel cell (DMFC), a phosphoric acid fuel cell (PAFC), an alkaline fuel cell (AFC), a molten carbonate fuel cell (MCFC) And a battery (SOFC).

2 schematically shows an electricity generating principle of a solid oxide fuel cell. The solid oxide fuel cell comprises an electrolyte layer and an anode and a cathode formed on both surfaces of the electrolyte layer. do. 2, which illustrates the principle of electricity generation of a solid oxide fuel cell, air is electrochemically reduced in the air electrode to generate oxygen ions, and the generated oxygen ions are transferred to the fuel electrode through the electrolyte layer. In the fuel electrode, fuel such as hydrogen, methanol, butane and the like is injected and the fuel is combined with oxygen ions and electrochemically oxidized to generate electrons and generate water. This reaction causes electrons to migrate to the external circuit.

Japanese Patent Application Laid-Open No. 2006-001813

It is an object of the present invention to provide a solid oxide fuel cell having a high electrical conductivity and increasing the area of a three phase boundary (TPB) where an electrode, an electrolyte layer and a gas meet where a redox reaction occurs at an electrode do.

Another object of the present invention is to provide a method of manufacturing a solar cell capable of reducing the manufacturing cost and increasing the compatibility with the air electrode by applying the LSC plate instead of the expensive silver-mesh (Ag-mesh) A solid oxide fuel cell.

The present invention relates to a fuel cell including a unit cell including a fuel electrode, an electrolyte layer and an air electrode;

A cathode current collector provided on the air electrode side of the unit cell; And

And a cathode current collector layer provided on a surface of the current collector opposite to the surface on which the unit cell is provided,

Wherein the cathode functional layer comprises lanthanum strontium cobalt oxide (LSC)

Wherein the cathode functional layer has a porosity of 10% or more and 90% or less.

The present invention also provides a battery module comprising the solid oxide fuel cell as a unit cell.

According to the solid oxide fuel cell according to the present specification, improvement in performance can be achieved by introducing a cathode functional layer into a cathode, ensuring sufficient electrical conductivity, and increasing the three phase boundary (TPB).

In addition, by using lanthanum strontium cobalt oxide (LSC), which is less expensive than the expensive precious metals such as silver mesh, as the cathode current collector layer material, cost competitiveness can be increased, compatibility with the air electrode Compatibility is excellent and the contact property with the air electrode is excellent.

1 shows a structure of a solid oxide fuel cell according to an embodiment of the present invention.
2 is a schematic diagram showing the electricity generation principle of a solid oxide fuel cell (SOFC).
Figs. 3 to 6 are SEM photographs of the cathode current collector layer of Production Examples 2 to 5. Fig.
7 shows performance evaluation of the solid oxide fuel cell according to Example 1 and Comparative Example 2 of the present invention.

Hereinafter, the present invention will be described in more detail.

When a member is referred to herein as being " on " another member, it includes not only a member in contact with another member but also another member between the two members.

Whenever a component is referred to as " comprising ", it is to be understood that the component may include other components as well, without departing from the scope of the present invention.

In this specification, the unit cell may include a fuel electrode, an air electrode opposed to the fuel electrode, and an electrolyte layer provided between the fuel electrode and the air electrode.

In the present specification, the cathode functional layer is distinguished from the cathode current collector.

The present invention relates to a fuel cell including a unit cell including a fuel electrode, an electrolyte layer and an air electrode;

A cathode current collector provided on the air electrode side of the unit cell; And

And a cathode current collector layer provided on a surface of the current collector opposite to the surface on which the unit cell is provided,

Wherein the cathode functional layer comprises lanthanum strontium cobalt oxide (LSC)

Wherein the cathode functional layer has a porosity of 10% or more and 90% or less. Since the solid oxide fuel cell includes a cathode active layer separately manufactured, the solid oxide fuel cell has a better current collecting function than a current collector manufactured by applying a conventional slurry. Specifically, the functions described above can be maximized by changing the porosity, pore size density, or thickness of the functional collector layer included in the functional current collecting layer.

1, a solid oxide fuel cell according to an embodiment of the present invention includes a unit cell 10 including a fuel electrode 101, an electrolyte layer 102, and an air electrode 103; An air electrode collector 20 provided on the air electrode 103 side of the unit cell 10; And a cathode functional layer 30 on the opposite side of the surface of the air electrode collector 20 on which the unit cell 10 is provided.

In the present specification, the cathode functionally-collecting layer may be a porous layer containing a plurality of pores. The pores are included so that the air electrode functional collector layer can directly contact the air or the fuel gas to the air electrode or the fuel electrode.

Since the solid oxide fuel cell includes the cathode functional layer, the durability is improved.

In one embodiment of the present invention, the cathode functional layer may further include a coating layer on the surface thereof.

In one embodiment of the present invention, the porosity of the cathode functional storage layer may be 10% or more and 90% or less, preferably 30% or more and 85% or less, more preferably 50% or more and 75% or less. When the above numerical range is satisfied, the air flow is smooth and the cell performance can be excellent, and the strength of the cathode current collector layer is maintained high, and the durability is excellent.

The porosity can be measured by a method commonly used in the field to which this technique belongs. For example, the porosity (P ₀ ) can be calculated according to the following equation, as a percentage of the volume at which the pores are located in the total volume of the cathode functional storage layer.

In order to measure the porosity, it is washed in an ultrasonic washing machine and dried in a circulating dryer at 100 ° C for 24 hours in order to remove impurities. Thereafter, the weight of the dried specimen is measured and taken as the dry weight W ₁ . Then, the dried sample is immersed in distilled water, boiled for 3 hours, cooled to room temperature, and this is called a catcher sample. The catcher sample is fixed in water using wire, and the value obtained by subtracting the weight of the wire is the weight W ₂ in the water of the catcher sample. Thereafter, the catcher sample is taken out of the water, the surface moisture is removed, and the weight is measured, which is called the weight W ₃ of the catcher sample.

In one embodiment of the present disclosure, the cathode functional layer has an average diameter of 0.05 mm to 1 mm, preferably an average diameter of 0.1 mm to 0.3 mm, more preferably an average diameter of 0.2 mm to 0.25 mm Including pores. When the above numerical range is satisfied, the air flow is smooth and the cell performance can be excellent, and the strength of the cathode current collector layer is maintained high, and the durability is excellent.

In one embodiment of the present disclosure, the cathode functional layer is a perforated plate. The perforated plate means a plate having pores formed through a separate perforation process. In this case, since the shape of the pores can be easily controlled as compared with the current collector layer formed by applying a conventional slurry, it is possible to provide a cathode active material layer having desired performance.

In one embodiment of the present invention, the areal density of the cathode functional storage layer is in the range of 50 g / m ² to 1,000 g / m ² , preferably 100 g / m ² based on the area of the cathode functional storage layer. m ² to 500 g / m ² , more preferably 200 g / m ² to 300 g / m ² . When the above numerical range is satisfied, the air flow is smooth and the cell performance can be excellent, and the strength of the cathode current collector layer is maintained high, and the durability is excellent. The surface density may mean the weight (g) of the cathode electrode functional layer and the area (m ² ) of either surface of the cathode electrode functional layer. For example, the surface area of one side of the cathode current collector layer is the area L * multiplied by the width L and the length W formed by the rectangle, assuming that one side of the cathode current collector layer is a rectangular plate. W).

In one embodiment of the present disclosure, the cathode functional layer has a thickness of 0.5 mm to 2 mm, preferably 0.7 mm to 1.5 mm, and more preferably 0.75 mm to 1.0 mm. When the thickness of the cathode current collector layer satisfies the above range, there is an advantage that the current collector layer is not damaged at the time of pore formation without affecting the entire thickness of the entire fuel cell stack.

In one embodiment of the present invention, the pores may be uniformly formed in the same shape or size. For example, the pores may be formed in the same shape or size as adjacent pores in the row direction and in the column direction, and may have the same shape and size as the pores adjacent to each other in the row direction and the column direction. .

In one embodiment of the present invention, the pores may be formed in a structure that is deviated from pores in the row direction or the column direction which are adjacent to each other. The meaning of the mutually-shifted structure means that the shapes and sizes of neighboring pores are different from each other. For example, the pores may be different in shape and size from the pores in the row direction and the column direction which are adjacent to each other. By having a structure in which the pores are displaced from each other in the row direction or in the column direction, the strength of the cathode functional layer can be improved and the possibility of being deformed by the load of the entire stack structure can be eliminated.

In one embodiment of the present invention, by varying the shape of the pores, it is possible to control the surface contact area of each structure of the cathode functional storage layer and the fuel cell. In addition, when an excessive exothermic reaction occurs in the electrochemical reaction of the fuel cell, the excessive heat can be efficiently dissipated by adjusting the shape of the plurality of pores so that the surface area of the cathode electrode functional layer is increased. can do.

In one embodiment of the present invention, the cross-sectional shape of the pores of the cathode functional layer may be circular, oval or polygonal.

In one embodiment of the present invention, the shape of the pores of the cathode functional storage layer may be a polygonal shape having at least one surface including a curved line. By making the cross-sectional shape of the pores round, it is possible to prevent a vortex phenomenon that may occur at angled corners, thereby preventing power generation efficiency from being deteriorated.

In one embodiment of the present disclosure, the pores may be formed by an etching process or a punching pressing process.

In one embodiment of the present disclosure, the cathode active material layer may be flat on one side or on both sides. This has the advantage that the electrical conductivity of the cathode functional layer can be kept high.

In one embodiment of the present disclosure, the cathode functional storage layer may be made of a single sheet of thin plate. Thereby, unlike the conventional air electrode current collector, which is formed by coating and drying on the air electrode, since there is no bonding site with the constitution of another fuel cell, the contact resistance can be lowered and the conductivity can be further improved There are advantages. Unlike the conventional coating method, it is easy to control the thickness of the current collector layer, and further, it is possible to manufacture a current collector layer having a high thickness. In addition, the load is dispersed by the surface contact in a stack structure in which a plurality of fuel cell unit cells are stacked, whereby the fuel cell is prevented from being broken, and physical stability can be secured. That is, the stack structure of the fuel cell including the cathode functional storage layer of the present invention is advantageous in that the stress state in which the load is transmitted is uniformly distributed as a whole, and physical stability can be secured.

In one embodiment of the present disclosure, the cathode functional storage layer comprises lanthanum strontium cobalt oxide (LSC). In this case, the three phase boundary (TPB) is sufficiently formed to improve the performance as the site of the catalytic reaction increases. Unlike the conventional gold-mesh structure layer, the cathode functional layer has an advantage of facilitating surface contact with other structures of the solid oxide fuel cell and reducing contact resistance. Specifically, the cathode active material layer included in the solid oxide fuel cell according to the present invention has excellent compatibility with the air electrode and the cathode current collector because it has a material of the same material as that of the cathode and the cathode collector, The area is increased and the activation site of the catalytic reaction is increased.

In one embodiment of the present invention, the lanthanum strontium cobalt oxide is represented by the following formula (1).

[Chemical Formula 1]

La _1-a Sr _a CoO _{3 -?}

In Formula 1,

0 < a < 1,

delta is a value that makes the oxide electrically neutral.

In one embodiment of the present specification, a may be 0.1 or more and 0.9 or more, preferably 0.2 or more and 0.6 or less, and still more preferably 0.3 or more and 0.5 or less.

In one embodiment of the present disclosure, the cathode functional layer has a density of 99% or more and an impurity content of less than 0.5% by weight, preferably less than 0.1% by weight.

In one embodiment of the present invention, one side of the air electrode current collector contacts one side of the air electrode functional current collector layer.

In one embodiment of the present invention, the thickness of the air electrode collector is 10 탆 to 30 탆, and preferably 15 탆 to 25 탆.

In one embodiment of the present disclosure, the electrical conductivity of the cathode functional storage layer at 650 ° C is at least 20 S / cm, at least 30 S / cm, at least 50 S / cm, at least 75 S / cm. &lt; / RTI &gt; When the above numerical range is satisfied, the electric conductivity of the cathode functional layer is excellent, and the performance of the fuel cell can be improved. The higher the electric conductivity of the cathode functional layer, the better, and therefore the upper limit is not particularly limited. The electric conductivity of the cathode functional layer is measured by pressing oxide particles and heat treatment at a temperature of 1200 ° C to form bulk samples and then platinum wires are bonded to the samples to form four probes (4 probe) method.

In one embodiment of the present invention, the lanthanum strontium cobalt oxide is contained in an amount of 3 wt% to 20 wt%, preferably 5 wt% to 10 wt%, more preferably 6 wt% to 10 wt%, based on the total weight of the cathode functional layer. 7 wt%. When the above range is satisfied, compatibility with the air electrode or the air electrode current collector of the air electrode functional current collector layer is increased, and the thermal stability with respect to other constituents is increased.

In one embodiment of the present invention, the method for producing the cathode electrode functional layer is not particularly limited. For example, a cathode electrode functional layer slurry is prepared, coated on a separate release paper, dried and sintered can do. The sintering process may be performed one or more times, preferably two times. If carried out two or more times, the sintering process may be further carried out between each sintering process.

In one embodiment of the present invention, the cathode functional layer slurry may further comprise at least one of the group consisting of a binder resin, a plasticizer, a dispersant, and a solvent, and the binder resin, plasticizer, , And conventional materials known in the art can be used.

In one embodiment of the present invention, the binder resin is not limited as long as it is a binder resin capable of imparting adhesion, and examples thereof include ethyl cellulose and alpha-terpineol, &Lt; / RTI &gt;

In one embodiment of the present disclosure, the plasticizer may be Di-butyl-phthalate (DBP).

In one embodiment of the present invention, the solvent is not limited as long as it can dissolve the binder resin, and any one or two or more kinds selected from the group consisting of butyl carbitol, terpineol and butyl carbitol acetate And may be preferably butyl carbitol.

The binder resin may include 10 wt% to 40 wt% based on the total weight of the cathode functional layer slurry.

The dispersant may be included in an amount of 5 wt% to 10 wt% based on the total weight of the cathode functional layer slurry.

The plasticizer may be included in an amount of 0.5 wt% to 3 wt% based on the total weight of the cathode functional layer slurry.

The solvent may include 15 wt% to 30 wt% based on the total weight of the cathode functional layer slurry.

The cathode functional storage layer may be a cathode functional storage layer plate prepared by sintering a green sheet prepared by tape casting the cathode functional storage layer slurry.

The solid oxide fuel cell according to one embodiment of the present invention may further include a cathode current collector provided on the air electrode side of the unit cell. The collector of the air electrode collects the electricity generated in the unit cell of the fuel cell and transfers it to the next unit cell.

The air electrode current collector may be formed by coating the air electrode current collector slurry on the air electrode by a screen printing method or a plasma spray method, drying, and a heat treatment process.

In one embodiment of the present invention, the air electrode collector may contact the air electrode.

In one embodiment of the present disclosure, the cathode functional layer may contact the cathode current collector.

In this specification, the meaning of "contacting" means that the cathode current collecting layer and the cathode current collector are in physical contact with each other. It does not mean that any one surface of the air electrode current collector is coupled to the entire surface of one surface of the cathode current collector layer and most of them are in contact with each other, It means to face the face.

In one embodiment of the present invention, the fuel electrode may include a first inorganic material having oxygen ion conductivity so as to be applicable to a fuel electrode for a solid oxide fuel cell. The type of the first inorganic material is not particularly limited, 1 mineral yttria (yttria) stabilized zirconium oxide (zirconia) (YSZ: (Y 2 O 3) x (ZrO 2) 1-x, x = 0.05 ~ 0.15), scandia stabilized zirconia (ScSZ: (Sc ₂ O ₃ ) _x (ZrO ₂ ) _1-x , x = 0.05 to 0.15), samarium doped ceria (SDC: (Sm ₂ O ₃ ) _x (CeO ₂ ) _{1 -x} , x = 0.02 to 0.4) doped ceria, (ceria) (GDC: (Gd 2 O 3) x (CeO 2) 1-x, x = 0.02 ~ 0.4), lanthanum strontium manganese oxide (lanthanum strontium manganese oxide: LSM) , lanthanum strontium cobalt ferrite (lanthanum strontium cobalt ferrite (LSCF), lanthanum strontium nickel ferrite (LSNF), lanthanum calcium nickel ferrite (LSC), lanthanum strontium cobalt oxide (GSC), lanthanum strontium ferrite (LSF), samarium strontium cobalt oxide oxide (SSC), barium strontium cobalt ferrite (BSCF), and lanthanum strontium gallium magnesium oxide (LSGM).

In one embodiment of the present specification, the fuel electrode may include at least one of nickel, copper, platinum, silver and palladium. Specifically, the fuel electrode may include nickel or copper.

In one embodiment of the present invention, the thickness of the fuel electrode may be 10 占 퐉 or more and 1000 占 퐉 or less, or 100 占 퐉 or more and 800 占 퐉 or less.

In one embodiment of the present invention, the porosity of the anode may be 10% or more and 50% or less, or 10% or more and 30% or less.

In one embodiment of the present invention, the diameter of the pores of the fuel electrode may be 0.1 占 퐉 or more and 10 占 퐉 or less, 0.5 占 퐉 or more and 5 占 퐉 or less, or 0.5 占 퐉 or more and 2 占 퐉 or less.

In one embodiment of the present invention, the method of manufacturing the fuel electrode is not particularly limited. For example, the anode may be coated with an anode slurry, followed by drying and sintering, or coating and drying the anode slurry on a separate release sheet, A sheet may be prepared and fired together with the green sheet of the at least one green sheet for the anode or the green sheet of the neighboring layer to prepare the fuel electrode.

In one embodiment of the present invention, the thickness of the green sheet for fuel electrode may be 10 占 퐉 or more and 500 占 퐉 or less.

In one embodiment of the present invention, the fuel electrode slurry includes inorganic particles having oxygen ion conductivity, and if necessary, the anode slurry may further include at least one of a binder resin, a plasticizer, a dispersant, and a solvent, The binder resin, plasticizer, dispersant, and solvent are not particularly limited, and any of the conventional materials known in the art may be used, or the materials described above may be used.

In one embodiment of the present invention, the content of the inorganic particle having oxygen ion conductivity is 10 wt% or more and 70 wt% or less based on the total weight of the anode slurry, the content of the solvent is 10 wt% or more and 30 wt% %, The content of the dispersant is 5 wt% or more and 10 wt% or less, the content of the plasticizer is 0.5 wt% or more and 3 wt% or less, and the binder is 10 wt% or more and 30 wt% or less.

In one embodiment of the present invention, the fuel electrode slurry may further include NiO. The volume ratio of the inorganic particle having oxygen ion conductivity to NiO may be 1: 3 to 3: 1 vol%.

In one embodiment of the present invention, the fuel electrode slurry may further include carbon black. The content of the carbon black may be 1 wt% or more and 20 wt% or less based on the total weight of the anode slurry.

In one embodiment of the present invention, the fuel electrode may be provided on a separate porous ceramic support or a porous metal support, or may include an anode support and an anode functional layer. At this time, the fuel electrode support is a layer containing the same inorganic substance as the anode function layer but supporting another layer because the porosity is higher than that of the anode function layer and is relatively thick, and the anode function layer is provided between the anode support and the electrolyte layer, And may be a layer running the main role as the anode.

When the fuel electrode is provided on the porous ceramic support or the porous metal support, the prepared green sheet for the anode is laminated on the fired porous ceramic support or the porous metal support, Can be manufactured.

In one embodiment of the present invention, when the anode includes the anode electrode support and the anode electrode functional layer, the green sheet for the anode electrode functional layer may be laminated on the sintered anode electrode support and fired to produce the anode.

In one embodiment of the present invention, the fuel electrode slurry may further include NiO.

In this specification, the green sheet means a film in the form of a film in a state where it can be processed in the next step, which is not a complete final product. In other words, the green sheet is coated with a coating composition containing inorganic particles and a solvent and dried in a sheet form, and the green sheet refers to a semi-dry sheet capable of maintaining a sheet form while containing a slight amount of solvent.

In one embodiment of the present specification, the anode may comprise a porous ceramic support. Porous ceramic support refers to a layer that is thicker relative to other layers and supports different layers of the solid oxide fuel cell. The porous ceramic support is preferably porous to allow fuel to be injected into the fuel electrode. The porous ceramic support serves to electrochemically oxidize the fuel and transfer electrons.

In one embodiment of the present disclosure, the porous ceramic support may comprise a metal and an inorganic oxide having oxygen ion conductivity.

In one embodiment of the present disclosure, the metal is selected from the group consisting of Zr, Ce, Ti, Mg, Al, Si, Mn, Fe, Co, Ni, Cu, Zn, Mo, Y, Nb, Sn, Nd. &Lt; / RTI &gt; Preferably, Ni can be used. Ni has high electron conductivity and adsorbs hydrogen and hydrocarbon-based fuel, and can exhibit high electrode catalyst activity. In addition, it is advantageous as an electrode material in terms of low cost compared to platinum.

In one embodiment of the present disclosure, the inorganic oxide having oxygen ion conductivity is selected from the group consisting of gadolinium-doped ceria (GDC), gadolinium-doped zirconia (GDZ), samarium-doped ceria (SDC), samarium-doped zirconia (SDZ), yttrium-doped ceria (YDC), yttrium-doped zirconia (YDZ), yttria stabilized zirconia (YSZ), and scandia stabilized zirconia (ScSZ). (GDC) doped with gadolinium, gadolinium (GDZ) doped with gadolinium, ceria doped with samarium (SDC), zirconia doped with samarium (SDZ), yttrium doped with ceria Doped zirconia (YDZ), and scandia stabilized zirconia (ScSZ). More preferably, gadolinium-doped ceria (GDC) can be used. When GDC is used, there is an advantage that operation can be performed at a low temperature of about 500 ° C to 700 ° C. When a material having higher ionic conductivity than an inorganic oxide such as YSZ such as GDC is used, the battery efficiency (output) can be increased. Accordingly, it is possible to have a high output value even in a middle-low temperature. When the fuel cell is operated at a low temperature of about 500 ° C. to 700 ° C., the degradation rate of the cell is drastically reduced and the cost of other components other than the cell can be reduced. .

In one embodiment of the present invention, the porosity of the porous ceramic support may be 20% or more and 60% or less, and preferably 30% or more and 50% or less.

In one embodiment of the present invention, the diameter of the pores of the porous ceramic support may be 0.1 μm or more and 10 μm or less, preferably 0.5 μm or more and 5 μm or less, and more preferably 0.5 μm or more and 2 μm or less. The porosity of the porous ceramic support and the diameter of the pores may be the same as those of the pores of the cathode functional layer.

In one embodiment of the present invention, the size of the pores may be controlled according to the type of pore former such as carbon black, polymer, and the like.

In one embodiment of the present invention, the porous ceramic substrate has no oxygen ion conductivity and electrical conductivity, or oxygen ion conductivity and electrical conductivity, but does not meet oxygen ion conductivity and electrical conductivity required as a fuel electrode, It may be made of ceramics, but its material may be inexpensive.

In one embodiment of the present invention, the thickness of the porous ceramic support may be 200 μm or more and 5 mm or less, preferably 500 μm or more and 2 mm or less. In this case, the reactants and products can be smoothly moved during the operation of the battery, and the required mechanical strength can be maintained.

In one embodiment of the present invention, the method of preparing the porous ceramic support is not particularly limited, but the porous ceramic support slurry may be coated on the substrate, dried and then sintered. Specifically, the porous ceramic support slurry may be coated on a substrate and dried to prepare a green sheet for a porous ceramic support, and the green sheet may be moved and laminated to be separately fired or fired simultaneously with another green sheet .

In one embodiment of the present disclosure, the thickness of the green sheet for the porous ceramic support may be 400 m or more and 1500 m or less.

In one embodiment of the present invention, the electrolyte layer may include a second inorganic material having oxygen ion conductivity, and the second inorganic material is not particularly limited, but the second inorganic material may be yttria stabilized zirconium oxide (zirconia) (YSZ: (Y 2 O 3) x (ZrO2) 1-x, x = 0.05 ~ 0.15), scandia stabilized zirconia _{(ScSZ: (Sc 2 O 3} ) x (ZrO 2) 1-x , x = 0.05 ~ 0.15), samarium-doped ceria (ceria) (SDC: (Sm 2 O 3) x (CeO 2) 1-x, x = 0.02 ~ 0.4), gadolinium-doped ceria (ceria) (GDC: (Gd ₂ O ₃ ) _x (CeO ₂ ) _1-x , x = 0.02 to 0.4), lanthanum strontium manganese oxide (LSM), lanthanum strontium cobalt ferrite (LSCF), lanthanum strontium nickel ferrite Lanthanum strontium nickel ferrite (LSNF), lanthanum calcium nickel ferrite (LCNF), lanthanum strontium copper oxide (LSC) gadolinium strontium cobalt oxide (GSC), lanthanum strontium ferrite (LSF), samarium strontium cobalt oxide (SSC), and barium strontium cobalt ferrite cobalt ferrite (BSCF), and lanthanum strontium gallium magnesium oxide (LSGM).

In one embodiment of the present invention, the second inorganic material of the electrolyte layer may be the same as the first inorganic material of the anode.

In one embodiment of the present invention, the thickness of the electrolyte layer may be 3 탆 or more and 30 탆 or less. Specifically, the thickness of the electrolyte layer may be 3 탆 or more and 10 탆 or less.

The method for producing the electrolyte layer is not particularly limited. For example, the electrolyte layer slurry may be coated on the green sheet for a sintered fuel electrode or anode, dried and cured, or the electrolyte layer slurry may be coated on a separate release sheet and dried To prepare an electrolyte layer green sheet, laminating the prepared electrolyte layer green sheet onto a sintered fuel electrode or a green sheet for a fuel electrode, and then curing the electrolyte sheet to produce an electrolyte layer.

In one embodiment of the present invention, the thickness of the electrolyte layer green sheet may be 10 mu m or more and 100 mu m or less.

In one embodiment of the present disclosure, the electrolyte layer slurry includes second inorganic particles having oxygen ion conductivity, and if necessary, the electrolyte layer slurry may further include a binder resin, a plasticizer, a dispersant, and a solvent, The binder resin, the plasticizer, the dispersing agent and the solvent are not particularly limited, and conventional materials known in the art may be used, or the materials described above may be used.

In one embodiment of the present invention, the content of the inorganic particle having oxygen ion conductivity is 10% by weight or more and 70% by weight or less based on the total weight of the electrolyte layer slurry, the content of the solvent is 10% The content of the dispersant is 5 wt% or more and 10 wt% or less, the content of the plasticizer is 0.5 wt% or more and 3 wt% or less, and the binder is 10 wt% or more and 30 wt% or less.

In one embodiment of the present invention, the electrolyte layer may be a Bi-layer structure. The bilayer structure may include a bottom electrolyte layer E1 and a top electrolyte layer E2. The lower electrolyte layer E1 is an electrolyte layer provided on the side of the fuel electrode in the solid oxide fuel cell and the upper electrolyte layer E2 is an electrolyte layer provided on the air electrode side.

In one embodiment of the present invention, the first inorganic material or the second inorganic material may have an oxygen ion conductivity of at least 0.01 S / cm at 650 ° C. The oxygen ion conductivity of the inorganic substance is preferably as high as possible, and therefore the upper limit of the oxygen ion conductivity of the inorganic substance is not particularly limited.

In one embodiment of the present invention, the air electrode may include a third inorganic material having oxygen ion conductivity so as to be applicable to an air electrode for a solid oxide fuel cell, and the kind of the third inorganic material is not particularly limited, 3 minerals yttria (yttria) stabilized zirconium oxide (zirconia) (YSZ: (Y 2 O 3) x (ZrO 2) 1-x, x = 0.05 ~ 0.15), scandia stabilized zirconia (ScSZ: (Sc ₂ O ₃ ) _x (ZrO ₂ ) _1-x , x = 0.05 to 0.15), samarium doped ceria (SDC: (Sm ₂ O ₃ ) _x (CeO ₂ ) _{1 -x} , x = 0.02 to 0.4) doped ceria, (ceria) (GDC: (Gd 2 O 3) x (CeO 2) 1-x, x = 0.02 ~ 0.4), lanthanum strontium manganese oxide (lanthanum strontium manganese oxide: LSM) , lanthanum strontium cobalt ferrite (lanthanum strontium cobalt ferrite (LSCF), lanthanum strontium nickel ferrite (LSNF), lanthanum calcium nickel ferrite ferrite (LCNF), lanthanum strontium copper oxide (LSC), gadolinium strontium cobalt oxide (GSC), lanthanum strontium ferrite (LSF), samarium strontium cobalt oxide oxide (SSC), barium strontium cobalt ferrite (BSCF), and lanthanum strontium gallium magnesium oxide (LSGM).

In one embodiment of the present invention, the thickness of the air electrode may be 10 μm or more and 100 μm or less. Specifically, the thickness of the air electrode may be 20 占 퐉 or more and 50 占 퐉 or less.

In one embodiment of the present invention, the porosity of the air electrode may be 10% or more and 50% or less. Specifically, the porosity of the air electrode may be 20% or more and 40% or less.

In one embodiment of the present invention, the diameter of the pores of the air electrode may be 0.1 μm or more and 10 μm or less. Specifically, the diameter of the pores of the air electrode may be 0.5 占 퐉 or more and 5 占 퐉 or less. More specifically, the diameter of the air electrode may be 0.5 占 퐉 or more and 2 占 퐉 or less.

In one embodiment of the present invention, the method of manufacturing the air electrode is not particularly limited. For example, an air electrode slurry may be coated on the sintered electrolyte layer, followed by drying and curing the air electrode slurry, or coating the air electrode slurry on a separate release paper And dried to prepare a green sheet for an air electrode. The prepared green sheet for an air electrode is laminated on a sintered electrolyte layer and then cured to prepare an air electrode.

In one embodiment of the present invention, the thickness of the green sheet for the air electrode may be 10 μm or more and 100 μm or less.

In one embodiment of the present invention, the air electrode slurry includes third inorganic particles having oxygen ion conductivity, and if necessary, the air electrode slurry may further include a binder resin, a plasticizer, a dispersant, and a solvent, The resin, plasticizer, dispersant, and solvent are not particularly limited, and any conventional materials known in the art may be used, or the materials described above may be used.

The solid oxide fuel cell according to one embodiment of the present invention may further include a first separator plate on the opposite side of the surface of the cathode current collector layer on which the cathode current collector layer is provided.

The solid oxide fuel cell according to an embodiment of the present invention may further include a second separator plate on the opposite side of the surface of the anode electrode on which the unit cell is provided.

In this specification, the first separator and the second separator may be a conductive substrate. The conductive substrate is not limited as long as it has a low ionic conductivity and a high electronic conductivity. Generally, there are a ceramic substrate or a metal substrate such as LaCrO ₃ , and a preferable example is a metal substrate.

A preferable example of the conductive substrate is a ferritic stainless steel (FSS) substrate. When the ferritic stainless steel sheet is used as the conductive substrate, the thermal conductivity is excellent and the stack temperature distribution becomes uniform, the thermal stress can be lowered in the flat stack, the mechanical strength is excellent, and the electrical conductivity is excellent .

In one embodiment of the present invention, the conductivity of the conductive substrate may be 10 ⁴ S / cm or more.

In one embodiment of the present invention, the thickness of the conductive substrate may be 0.1 mm or more and 30 mm or less.

In one embodiment of the present invention, the ferritic stainless steel is not particularly limited, but preferable examples thereof include Crofer 22 (manufactured by ThyssenKrupp), STS441 (manufactured by POSCO), STS430 (manufactured by POSCO), Crofer 22 APU Manufactured by ThyssenKrupp).

In one embodiment of the present invention, the shape of the fuel cell is not limited, and may be, for example, a coin shape, a flat plate shape, a cylindrical shape, a horn shape, a button shape, a sheet shape or a laminate shape.

In one embodiment of the present specification, the fuel cell can be specifically used as a power source for an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle or a power storage device.

The present invention provides a battery module including the solid oxide fuel cell as a unit cell.

Hereinafter, the present invention will be described in detail by way of examples with reference to the drawings. However, the embodiments according to the present disclosure can be modified in various other forms, and the scope of the present specification is not construed as being limited to the embodiments described below. Embodiments of the present disclosure are provided to more fully describe the present disclosure to those of ordinary skill in the art.

<Experimental Example>

&Lt; Preparation Example 1: Preparation of positive electrode functional layer 1 >

A functional layer of a cathode active layer having a composition of 18.2 wt% of a solvent, 6.2 wt% of a dispersant, 1.2 wt% of a plasticizer, 24.2 wt% of a binder, and other LSC powder (0.8 mol of La, 0.2 mol of Sr, 1.0 mol of Co) , A mold having a certain shape is placed on a green sheet, punching is performed by a punching method in which pores are formed by punching with a hammer, followed by a first sintering process in which the mold is maintained at a temperature of 1000 캜 for 3 hours, And then subjected to a second sintering process in which the mixture was held at a temperature of 1200 ° C for 3 hours to be slowly cooled, thereby preparing a cathode current collector layer plate 1. At this time, the porosity of the plate for the cathode electrode functional layer was 63.07%.

Other pore characteristics of the plate are shown in Table 1 below.

Pore size average 0.2 mm to 0.5 mm Plate thickness 0.8mm Pore shape Spherical (circular section) The surface density of the plate 450 g / m ²

&Lt; Preparation Example 2: Preparation of cathode active material layer 2 >

The cathode functionally-functionalized current-collecting layer 2 was prepared except that the porosity of the plate for the cathode-functioning current-collecting layer was 65.89%.

&Lt; Preparation Example 3: Preparation of positive electrode functional layer 3 >

Cathode Electrode Functional current-collecting layer 3 was prepared except that the porosity of the plate for the functional current-collecting layer was 72.16%.

&Lt; Preparation Example 4: Preparation of cathode active material layer 4 >

The cathode functionally-functionalized current collector layer 4 was prepared except that the porosity of the plate for the cathode current collector layer was 83.42%.

PREPARATION EXAMPLE 5: Preparation of cathode active material layer 5 &gt;

The cathode functionally-functionalized current-collecting layer 5 was prepared except that the porosity of the plate for the cathode-functioning current-collecting layer was 92.29%.

&Lt; Example 1 >

The solid oxide fuel cell includes a unit cell composed of an anode support layer (ASL), an anode functional layer (AFL), an electrolyte layer (EL), a cathode layer (CL) Lt; RTI ID = 0.0 &gt; functional &lt; / RTI &gt;

1) Preparation of anode support

An anode support having a thickness of 100 mu m to 200 mu m was obtained by tape casting the anode support slurry. At this time, the anode slurry contains GDC, NiO and Carbon Black as inorganic substances. At this time, the ratio of GDC to NiO is 50: 50 vol%, and carbon black is included in an amount of 10 wt% based on the total weight of the slurry. The fuel electrode support slurry contains 18.2 wt% of solvent, 6.2 wt% of dispersant, 1.2 wt% of plasticizer, and 24.2 wt% of binder based on the total weight of the slurry.

2) Preparation of Green Sheet for Anode Functional Layer

A fuel electrode functional layer green sheet having a thickness of 10 mu m was cast by coating the fuel electrode functional layer slurry on the fuel electrode support. The anode functional layer slurry was the same as the fuel anode support slurry except that carbon black was not included and the composition ratio of GDC and NiO was adjusted to 60:40 vol%.

3) Preparation of electrolyte green sheet

The electrolyte slurry was coated on the anode support coated with the anode functional layer green sheet to cast an electrolyte green sheet having a thickness of 20 탆. The electrolyte slurry was the same as the fuel electrode support slurry except that it contained only GDC without NiO and carbon black as an inorganic material.

4) Manufacture of Half-cell

The fuel electrode support, the anode functional layer green sheet, and the electrolyte green sheet were sequentially laminated and then sintered at 1400 ° C to produce a half cell. At this time, the thicknesses of the anode support, the anode functional layer and the electrolyte layer after sintering were 800 탆, 20 탆 and 20 탆, respectively.

5)

The cathode slurry was coated and dried on the electrolyte layer of the half cell by screen printing method, and then heat-treated at 1000 ° C for 3 hours and slowly cooled to form an air electrode. The air electrode slurry contained LSCF-6428 (La _0.6 Sr _0.4 Co _0.2 Fe _0.8 O _{3 -δ} ) powder and ESL-441 as a binder in a weight ratio of 60:40. At this time, a 3-roll mill operation was performed to prepare an air electrode slurry in the form of a paste.

6) lamination of air pole collector

The air electrode current collector slurry was coated on the cathode layer by a screen printing method and dried, followed by heat treatment at a temperature of 1000 캜 for 3 hours to form a cathode current collector. The cathode current collector slurry contained LSC-6410 (La _0.6 Sr _0.4 Co _1.0 O _{3 -δ} ) powder and ESL-441 as a binder in a weight ratio of 60:40. At this time, a 3-roll mill operation was performed to prepare a cathode current collector slurry in the form of a paste.

7) cathode electrode functional layer lamination

Next, the cathode active material layer prepared in Production Example 1 was laminated on the cathode current collector to prepare a solid oxide fuel cell.

&Lt; Example 2 >

A solid oxide fuel cell was fabricated in the same manner as in Example 1 except that the cathode functionally-collecting layer prepared in Preparation Example 2 was laminated.

&Lt; Example 3 >

A solid oxide fuel cell was fabricated in the same manner as in Example 1 except that the cathode functional layer formed in Production Example 3 was laminated.

<Example 4>

A solid oxide fuel cell was fabricated in the same manner as in Example 1, except that the cathode functional layer formed in Production Example 4 was laminated.

&Lt; Comparative Example 1 &

A solid oxide fuel cell was fabricated in the same manner as in Example 1 except that the cathode functionally-collecting layer prepared in Preparation Example 5 was laminated.

&Lt; Comparative Example 2 &

A solid oxide fuel cell was produced in the same manner as in Example 1 except that the cathode functional layer was not laminated.

EXPERIMENTAL EXAMPLE 1: Change in Electrical Conductivity Characteristics of the Electrode Functional Current Collector Layer [

The electrical conductivity of the cathode functional layer obtained in the Preparation Example was measured and shown in Table 2 below. At this time, the resistance was measured by a 4-probe 2-wire resistance measurement method using a multimeter (multimeter 3706A, manufactured by KEITHLYE) at a temperature of 650 ° C.

division Electrical conductivity (S / cm @ 650 ℃) Production Example 1 88.25 Production Example 2 77.73 Production Example 3 31.25 Production Example 4 23.65 Production Example 5 9.22

Experimental Example 2: Observation of surface characteristics [

Scanning Electron Microscope (SEM) photographs of the surface of the functional current collecting layer prepared in Production Examples 2 to 5 are shown in Figs. 3 to 6, respectively.

&Lt; Experimental Example 3: Measurement of current-voltage and power density >

For measurement of the performance of the fuel cell manufactured in Examples and Comparative Examples, a current collector (Ag mesh) was attached to the fuel electrode and the air electrode and sealed. At this time, a solid oxide fuel cell having five unit cells sequentially stacked was manufactured.

The performance of the cell was measured while changing the current density at 650 ° C. The results are shown in Fig. The OCV and OPD of each of the examples and comparative examples when the current density is 0.5 A / cm &lt; ² &gt; are shown in Table 3 and Fig.

division Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 OCV 1.12 Unmeasured 1.13 Unmeasured 1.12 1.13 OPD 350 Unmeasured 325 Unmeasured 310 290

* OCV: Open circuit voltage at 650 ℃

* OPD (operating power density): Output power (unit: mW / cm ² ) when a current density of 0.5 A / cm ² is applied at 650 ° C.

From the above results, it was confirmed that the OPD was reduced in the high-density region of 0.5 A / cm ² when the functional current-collecting layer was not included (Comparative Example 2) or when the porosity of the functional current-collecting layer was too large.

On the other hand, in the case of Examples 1 and 3 in which the porosity range of the functional current collector layer was controlled to a certain range or less, it was confirmed that the OPD was kept high in the high density region of 0.5 A / cm ² . This is because the battery was supplied smoothly for the reduction reaction of oxygen gas generated in the air electrode.

10: electrolyte layer
20: air electrode
30: positive electrode functional layer
40: cathode collector
50: anode

Claims (11)

A unit cell including a fuel electrode, an electrolyte layer and an air electrode;
A cathode current collector provided on the air electrode side of the unit cell; And
And a cathode current collector layer provided on a surface of the current collector opposite to the surface on which the unit cell is provided,
Wherein the cathode functional layer comprises lanthanum strontium cobalt oxide (LSC)
Wherein the porous functional layer has a porosity of 10% or more and 90% or less. 2. The solid oxide fuel cell of claim 1, wherein the cathode functional layer comprises pores having an average diameter of from about 0.05 mm to about 1 mm. The solid oxide fuel cell of claim 1, wherein the cathode functional layer is a perforated plate. The solid oxide fuel cell of claim 1, wherein the cathode functionalized current layer has an areal density of 50 g / m ² to 1,000 g / m ² based on the area of the cathode functional layer. The solid oxide fuel cell according to claim 1, wherein the cross-sectional shape of the pores of the cathode functional storage layer is any one of circular, elliptical, and polygonal. The solid oxide fuel cell according to claim 1, wherein the thickness of the air electrode current collector is 10 占 퐉 to 30 占 퐉. The solid oxide fuel cell according to claim 1, wherein the cathode functional layer has a thickness of 0.5 mm to 2 mm. The solid oxide fuel cell according to claim 1, wherein the cathode functional conducting layer has an electric conductivity of at least 20 S / cm at 650 ° C. The solid oxide fuel cell according to claim 1, wherein the lanthanum strontium cobalt oxide is represented by the following formula (1).
[Chemical Formula 1]
La _1-a Sr _a CoO _{3 -?}
In Formula 1,
0 < a < 1,
delta is a value that makes the oxide electrically neutral. The solid oxide fuel cell of claim 1, wherein the cathode functional layer comprises the lanthanum strontium cobalt oxide in an amount of 3 wt% to 20 wt% based on the total weight of the cathode active layer. A battery module comprising the solid oxide fuel cell according to any one of claims 1 to 10 as a unit cell.

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