KR101653969B1 - A Manufacturing Method for Solid Oxide Fuel Cell - Google Patents

Abstract

The present invention relates to a solid oxide fuel cell manufacturing method comprising the steps of providing a plurality of slurries, sequentially laminating the plurality of slurries on a transfer film to form a laminate, and drying the laminate to prepare a green body .

Solid oxide, electrolyte, fuel cell, tape casting, co-sintering, SOFC

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a solid oxide fuel cell,

The present invention relates to a method for producing a solid oxide fuel cell.

A solid oxide fuel cell (SOFC) is a stack of unit cells including a cathode (anode, anode), an electrolyte, and an anode (cathode, cathode). The electrolyte serves as a passage through which oxygen ions move, and a cathode and an anode are provided on both surfaces of the electrolyte. A buffer layer may be inserted to prevent the reaction between the electrolyte and the anode.

An anode, an electrolyte, a buffer layer, and the like are formed by a tape casting method, respectively, and these are laminated and sintered to produce a unit cell of a solid oxide fuel cell.

The present invention is directed to a method for manufacturing a solid oxide fuel cell.

A method of manufacturing a solid oxide fuel cell according to an embodiment of the present invention includes the steps of providing a plurality of slurries, sequentially laminating the plurality of slurries on a transfer film to form a laminate, and drying the laminate to form a green body And the like.

The plurality of slurries may include a negative electrode support slurry, a negative electrode slurry, and an electrolyte slurry.

The method may further include a viscosity adjusting step of adjusting the viscosity of the slurry of the cathode support to the highest value and the viscosity of the slurry of the electrolyte to be the lowest before providing the plurality of slurries. In the viscosity control step, the viscosity of the slurry of the cathode slurry is adjusted to 3,000 cps or more and 50,000 cps or less, and the viscosity of the slurry of the anode slurry is controlled to be 1,000 cps or more and 8,000 cps or less. The viscosity of the slurry of the electrolyte is 300 cps or more and 3,000 cps or less .

In the step of forming the laminate, the negative electrode slurry and the electrolyte slurry may be sequentially laminated on the negative electrode support slurry after the negative electrode slurry is laminated on the transfer film.

The plurality of slurries may further comprise a buffer layer slurry and may further comprise a viscosity adjustment step to maximize the viscosity of the cathode support slurry and to minimize the viscosity of the buffer layer slurry prior to providing the plurality of slurries have. The viscosity of the negative electrode slurry is controlled to be not less than 3,000 cps and not more than 50,000 cps and the viscosity of the negative electrode slurry is controlled not less than 1,000 cps and not more than 8,000 cps. cps or less, and the viscosity of the buffer layer slurry may be adjusted to 100 cps or more and 2,000 cps or less.

The plurality of slurries may further comprise a buffer layer slurry, and the step of adding a sintering aid to the buffer layer slurry may be further included before the step of providing the plurality of slurries. The sintering aid may include at least one selected from the group consisting of Al, Co, Zn, Ni, Fe, Ca, K, Li, Mg, Mn, Na, Zn and mixtures thereof.

The plurality of slurries may further include a buffer layer slurry, and the step of providing the buffer layer slurry with a particle size of 50 nm or more and 200 nm or less may be performed before the plurality of slurries are provided.

In the step of forming the laminate, the negative electrode slurry may be laminated on the transfer film, and then the negative electrode slurry, the electrolyte slurry and the buffer layer slurry may be sequentially deposited on the negative electrode support slurry.

And simultaneously sintering the green body after the step of manufacturing the green body. In the step of simultaneously sintering the green body, the sintering temperature may be 1,200 ° C or more and 1,500 ° C or less.

After the step of preparing the green body, the method may further include forming a buffer layer on the green body. In the step of forming the buffer layer, the buffer layer can be formed by a screen printing method or a wet spraying method.

And forming an anode on the buffer layer after forming the buffer layer. In the step of forming the anode, the anode may be formed by a screen printing method or a wet spraying method.

The present invention provides a method for manufacturing a solid oxide fuel cell.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, in order that those skilled in the art may easily implement the present invention. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly illustrate the present invention, parts not related to the description are omitted from the drawings, and like parts are denoted by similar reference numerals throughout the specification.

Generally, a solid oxide fuel cell refers to a stack of unit cells. However, in the following embodiments, a 'solid oxide fuel cell' refers to a unit cell for easy explanation.

1 is a process diagram showing a method for manufacturing a solid oxide fuel cell according to an embodiment of the present invention.

Referring to FIG. 1, a method for fabricating a solid oxide fuel cell according to an exemplary embodiment of the present invention includes providing a plurality of slurries S100, forming a laminate S200, (S300), and simultaneously sintering the green body (S400).

Providing a plurality of slurries (S100) is a step of providing a cathode support slurry, an anode slurry, an electrolyte slurry, a buffer layer slurry, and the like. These slurries form a cathode support layer, a cathode, an electrolyte, a buffer layer, and the like, respectively.

The anode support slurry may contain a transition metal oxide such as Ni, Fe, Cu, Co, an oxygen ion conductor or insulator mainly containing Zr or Ce, and a pore-forming agent.

The negative electrode slurry may contain a transition metal oxide such as Ni, Fe, Cu, Co, an oxygen ion conductor containing Zr or Ce as a main component, and a pore-forming agent.

The electrolyte slurry may include an oxygen ion conductor containing Zr as a main component.

The buffer layer slurry may include an oxygen ion conductor containing Ce as a main component. The oxygen ion conductor contained in the buffer layer slurry may have a particle size of 50 nm or more and 200 nm or less. When the particle size of the oxygen ion conductor is smaller than 50 nm or larger than 200 nm, the shrinkage ratio of the electrolyte and the buffer layer is different. In this case, the electrolyte or the buffer layer is cracked or warped at the time of simultaneous sintering.

Before the step SlOO of providing a plurality of slurries, a sintering auxiliary agent may be added to the buffer layer slurry. The sintering aids control the sintering behavior and shrinkage ratio of the buffer layer. The sintering aid may include any one selected from the group consisting of Al, Co, Zn, Ni, Fe, Ca, K, Li, Mg, Mn, Na, Zn and mixtures thereof.

The step of forming a laminate (S200) is a step of laminating a plurality of slurries using a tape casting apparatus.

Referring to FIG. 2, the tape casting apparatus 200 includes a cathode support slurry inlet 201, a cathode slurry inlet 203, and an electrolyte slurry inlet 205. The cathode slurry inlet 201 is disposed at the lowest position, and the anode slurry inlet 203 and the anode slurry inlet 205 are disposed above the cathode slurry inlet 201 and the cathode slurry inlet 202, respectively.

In the tape casting apparatus 200, a slurry discharge port 207 is formed. The slurry outlet 207 may be formed on the opposite side of the slurry inlet 201, 203, 205.

In addition, the tape casting apparatus 200 is provided with a carrier film 209 and a roller 211.

When the slurry is introduced into the slurry inlet ports 201, 203, and 205, respectively, the slurry is discharged from the slurry outlet port 207. The slurry to be discharged is deposited on the transfer film 209. In this process, the cathode support slurry 213 forms the lowest layer, and the cathode slurry 215 and the electrolyte slurry 217 are sequentially stacked thereon. It is the layered product 219 that these slurries 213, 215, and 217 are laminated on the transfer film 209.

On the other hand, a buffer layer slurry inlet may be provided in the tape casting apparatus 200. In this case, the buffer layer slurry can be laminated on the electrolyte slurry.

The anode may be formed in the buffer layer slurry by a screen printing method or a wet spraying method. Further, only two kinds of slurries can be put into a tape casting apparatus to produce a two-layered laminate.

The step of manufacturing a green body (S300) is a step of drying the laminate.

A green body may be produced without forming a buffer layer in the laminate. That is, the negative electrode support, the negative electrode and the electrolyte constitute a laminate. In this case, the method further includes forming a buffer layer after manufacturing the green body. The buffer layer can be formed on the green body by a screen printing method or a wet spray method.

After forming the buffer layer, the anode may be formed on the buffer layer. As the anode forming method, a screen printing method or a wet spraying method may be used.

In the step of simultaneously sintering the green body (S400), the green body is simultaneously sintered at 1,200 ° C or higher and 1,500 ° C or lower. When the sintering temperature is lower than 1,200 ° C, the green body is not sufficiently sintered. If the sintering temperature is higher than 1,500 ° C, it is difficult to obtain the desired porosity.

A negative electrode support, a negative electrode, an electrolyte and a buffer layer may be respectively formed by a tape casting method. That is, a negative electrode support slurry is laminated on a transfer film to form a negative electrode support sheet, an electrolyte slurry is laminated on the transfer film to form an electrolyte sheet, and a buffer layer slurry is laminated on the transfer film to form a buffer layer sheet. Each of these sheets is laminated to form a laminate. In this case, a so-called lamination process of pressing them is required. The lamination step is a step of pressing the laminate at a temperature of about 70 캜 or higher and 150 캜 / ㎠ or higher and 250 ㎏ / ㎠ for a predetermined time.

However, in the embodiment of the present invention, a plurality of slurries are molded simultaneously and then laminated on a transfer film to form a laminate. That is, in the embodiment of the present invention, a laminate can be formed by using the tape casting method only once. In this case, since the cathode support, the cathode, the electrolyte, the buffer layer and the like are not required to be tape-cast, respectively, the process is reduced.

When forming a plurality of slurries at the same time, it is important to adjust the viscosity of the slurry and to form the slurries. In the case of a cathode-supported solid oxide fuel cell, the cathode support, the cathode, the electrolyte, and the buffer layer become thinner in this order. When the viscosity of the slurry is low, the thickness after molding is also thin.

Generally, the thicker the electrolyte or the buffer layer, the greater the resistance, so the fuel cell output decreases. The thinner the thickness of the electrolyte or the buffer layer, the better. However, if the electrolyte is too thin, internal defects may occur and fuel and oxygen may be mixed. In this case, since the cell performance is deteriorated, the thickness should be maintained to such an extent that no defect occurs.

To improve battery performance, it is necessary to make a lot of triple points of fuel - oxygen ion conductor - electron conductor on the cathode. Therefore, the pores of the negative electrode become smaller than the pores of the support. If the cathode is thick, the fuel can not move well and the water vapor generated by the reaction can not move well, so the cell output decreases.

The thinner the anode support is, the better the performance is. However, the larger the cell, the greater the tendency to thicken the negative electrode support to increase the mechanical strength.

If multiple layers are to be formed, the lower viscosity slurry must be placed on the top layer to avoid defects in the drying process. If the viscosity of the lower layer is lower than that of the upper layer, the upper layer is dried before the lower layer is dried, and the solvent of the lower layer is volatilized, causing the upper layer surface to swell. To prevent these defects, the bottom layer should be formed in the order of the cathode support, the cathode, the electrolyte and the buffer layer, and the viscosity should be lowered from the lower layer to the upper layer. On the other hand, the viscosity of the slurry in contact with each other may be the same.

In an embodiment of the present invention, the viscosity of the negative electrode slurry is adjusted to 3,000 cps or more and 50,000 cps or less, and the viscosity of the negative electrode slurry is adjusted to 1,000 cps or more and 8,000 cps or less. Also, the viscosity of the electrolyte slurry is adjusted to 300 cps or more and 3,000 cps or less, and the viscosity of the buffer layer slurry is adjusted to 100 cps or more and 2,000 cps or less. Where cps represents centi Poise, the unit of viscosity.

If the viscosity of the negative electrode slurry is less than 3,000 cps, the viscosity is too low to form. As a result, it is difficult to make the cathode support sheet to have a desired thickness. If the viscosity of the negative electrode slurry exceeds 50,000 cps, the viscosity is too high and it is difficult to supply the slurry properly during molding.

When the viscosity of the negative electrode slurry is less than 1,000 cps, there is a problem of mixing with the electrolyte slurry. When the viscosity exceeds 8,000 cps, it is difficult to control the thickness of the negative electrode sheet to less than 30 탆.

When the viscosity of the electrolytic slurry is less than 300 cps, there is a problem of mixing with the buffer layer slurry in the die. When the viscosity exceeds 3,000 cps, it is difficult to form the sheet to a thickness of 10 탆 or less.

If the viscosity of the buffer layer slurry is less than 100 cps, it is mixed with the electrolyte slurry in the die, and if it exceeds 2,000 cps, it is difficult to form the sheet to a thickness of less than several micrometers.

The step of adjusting the viscosity of the slurry may be performed before the step (SlOO) of providing the plurality of slurries. The viscosity of the slurry can be controlled by increasing or decreasing the content of the solvent or by changing the type of the binder resin. That is, using a binder resin having a large molecular weight or reducing the content of the solvent increases the viscosity of the slurry. The viscosity of the slurry can be increased by using a ceramic powder having a large specific surface area.

Further, according to the embodiment of the present invention, since the lamination process can be omitted, time and cost can be reduced. Unlike the embodiment of the present invention, a lamination process is required in which the negative electrode support, the negative electrode, the electrolyte, the buffer layer and the like are respectively tape-casted and pressed and laminated.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, And it goes without saying that they belong to the scope of the present invention.

1 is a process diagram showing a method for manufacturing a solid oxide fuel cell according to an embodiment of the present invention.

2 is a schematic diagram illustrating a tape casting apparatus for use in manufacturing a solid oxide fuel cell according to an embodiment of the present invention.

Claims (21)

Providing a plurality of slurries, Sequentially stacking the plurality of slurries on a transfer film to form a laminate; and Drying the laminate to produce a green body ≪ / RTI > The method of claim 1, Wherein the plurality of slurries comprises a cathode support slurry, an anode slurry and an electrolyte slurry. 3. The method of claim 2, Before providing the plurality of slurries, Further comprising the step of adjusting the viscosity of the slurry of the cathode support to the highest level and the viscosity of the slurry of the electrolyte to the lowest level. 4. The method of claim 3, In the viscosity control step, Adjusting the viscosity of the negative electrode slurry to 3,000 cps or more and 50,000 cps or less, The viscosity of the negative electrode slurry is adjusted from 1,000 cps to 8,000 cps, Wherein the viscosity of the electrolyte slurry is adjusted to 300 cps or more and 3,000 cps or less. 5. The method according to any one of claims 2 to 4, In the step of forming the laminate, Depositing the anode support slurry on the transport film, and then sequentially laminating the anode slurry and the electrolyte slurry on the anode support slurry. 3. The method of claim 2, Wherein the plurality of slurries further comprise a buffer layer slurry, Before providing the plurality of slurries Further comprising the step of adjusting the viscosity of said cathode support slurry to the highest and viscosity of said buffer layer slurry to the lowest. The method of claim 6, In the viscosity control step, Adjusting the viscosity of the negative electrode slurry to 3,000 cps or more and 50,000 cps or less, The viscosity of the negative electrode slurry is adjusted from 1,000 cps to 8,000 cps, The viscosity of the electrolyte slurry is controlled to be 300 cps or more and 3,000 cps or less, Wherein the viscosity of the buffer layer slurry is adjusted to 100 cps or more and 2,000 cps or less. 3. The method of claim 2, Wherein the plurality of slurries further comprise a buffer layer slurry, Before providing the plurality of slurries Further comprising the step of adding a sintering aid to the buffer layer slurry. 9. The method of claim 8, Wherein the sintering aid comprises at least one selected from the group consisting of Al, Co, Zn, Ni, Fe, Ca, K, Li, Mg, Mn, Na, Zn and mixtures thereof. 3. The method of claim 2, Wherein the plurality of slurries further comprise a buffer layer slurry, Before providing the plurality of slurries Further comprising the step of making the particle size of the buffer layer slurry not less than 50 nm and not more than 200 nm. 11. The method according to any one of claims 6 to 10, In the step of forming the laminate, Depositing the negative electrode slurry on the transfer film, and then sequentially stacking the negative electrode slurry, the electrolyte slurry, and the buffer layer slurry on the negative electrode support slurry. 12. The method of claim 11, After the step of preparing the green body And simultaneously sintering the green body. ≪ RTI ID = 0.0 > 11. < / RTI > The method of claim 12, In the simultaneous sintering of the green body, Wherein the sintering temperature is 1,200 DEG C or more and 1,500 DEG C or less. 3. The method of claim 2, After the step of manufacturing the green body, Further comprising forming a buffer layer on the green body. The method of claim 14, In the step of forming the buffer layer, Wherein said buffer layer is formed by a screen printing method or a wet spraying method. 15. The method according to claim 14 or 15, After the step of forming the buffer layer, And simultaneously sintering the green body having the buffer layer formed thereon. 17. The method of claim 16, In the simultaneous sintering of the green body on which the buffer layer is formed, Wherein the sintering temperature is 1,200 DEG C or more and 1,500 DEG C or less. 15. The method according to claim 14 or 15, After the step of forming the buffer layer, And forming a positive electrode on the buffer layer. The method of claim 18, In the step of forming the anode, Wherein said anode is formed by a screen printing method or a wet spraying method. 20. The method of claim 19, After forming the anode on the buffer layer, And simultaneously sintering the green body having the buffer layer and the anode formed thereon. 20. The method of claim 20, In the simultaneous sintering of the green body having the buffer layer and the anode, Wherein the sintering temperature is 1,200 DEG C or more and 1,500 DEG C or less.

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