KR20220053277A - A carbon paper used in gas diffusion layer of fuel cell and a method of manufacturing thereof - Google Patents

Abstract

The present invention provides a method for producing carbon paper applied to a fuel cell gas diffusion layer capable of improving gas permeability. The method includes the steps of: preparing a polyvinyl alcohol impregnation solution by dissolving a polyvinyl alcohol resin in water; impregnating the carbon bale in the polyvinyl alcohol impregnation solution and drying it to bind the carbon fibers protruding from the surface of the carbon veil to suppress protrusion from the surface; impregnating the dried carbon veil with a phenol impregnating solution in which a phenol resin is dissolved; drying and curing the impregnated carbon veil; and carbonizing and graphitizing the cured carbon veil to burn the polyvinyl alcohol resin contained in the impregnated film of the carbon veil to form pores.

Description

Carbon paper applied to gas diffusion layer of fuel cell and manufacturing method thereof

The present invention relates to carbon paper and a method for manufacturing the same, which is applied to a gas diffusion layer of a fuel cell, can improve durability and performance of a fuel cell by suppressing the protrusion of carbon fibers from the surface, and has improved gas permeability; It relates to a manufacturing method thereof.

In general, a fuel cell is a device that generates electric energy by electrochemically reacting hydrogen and oxygen, and since it directly produces electricity without burning fuel, it is environmentally friendly and has very high power generation efficiency.

Here, the unit cell of the fuel cell is usually stacked in the order of an electrode plate (anode), a gas diffusion layer, a catalyst layer, an electrolyte layer, a catalyst layer, a gas diffusion layer, and an electrode plate (cathode), and hydrogen used as fuel is supplied to the anode. and oxygen is supplied to the cathode.

The principle of power generation of such a fuel cell is that hydrogen supplied to the anode passes through the gas diffusion layer and is separated into hydrogen ions (cations) and electrons by catalysis in the catalyst layer, and hydrogen ions (cations) pass through the electrolyte layer and enter the cathode. As the electrons move to the cathode through an external circuit, a current is generated.

In addition, on the cathode side, the fuel cell operates on the principle that hydrogen ions (cations) that have moved through the electrolyte layer, electrons that have moved through an external circuit, and supplied oxygen meet to generate water.

Among the components of such a fuel cell, the gas diffusion layer uniformly diffuses and supplies oxygen or hydrogen to the catalyst layer, moves generated electrons quickly, and requires characteristics such as strength to withstand external shocks, so it has excellent strength and electrical conductivity. It is made of carbon fiber-based carbon paper with

In general, carbon paper can be produced by impregnating a carbon veil with a phenol-impregnated solution and then carbonizing and graphitizing it. It can be manufactured through a (wet-laid) manufacturing process.

At this time, some carbon fibers are present on the surface of the carbon veil produced by the wet process while protruding in the vertical direction. , when applied to a fuel cell, it can affect the membrane electrode assembly (at least one of a catalyst layer, an electrolyte layer, and a gas diffusion layer) and act as a cause of lowering the durability and performance of the fuel cell. it is important

In addition, in order to increase the efficiency of the fuel cell, it is necessary to quickly and uniformly diffuse the gas supplied to the gas diffusion layer into the catalyst layer. For this reason, high gas permeability is required for the carbon paper of the gas diffusion layer. It is not easy to form pores in the carbon structure formed through the impregnation with the impregnation solution, so there is a limit to increase the gas permeability.

Patent Publication No. 2020-0076395 (published date: June 29, 2020) "Graphitized carbon substrate and gas diffusion layer employing the same"

In the present invention, carbon paper applied to the gas diffusion layer of a fuel cell and a method for manufacturing the same, specifically, suppressing the protrusion of carbon fibers from the surface of the carbon veil, and increasing the porosity by forming pores in the impregnated film (carbon structure) of the carbon veil An object of the present invention is to provide a carbon paper applied to a gas diffusion layer of a fuel cell capable of improving gas permeability.

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the description below. will be able

In order to solve the above problems, the present invention provides a step of dissolving a polyvinyl alcohol resin in water to prepare a polyvinyl alcohol impregnating solution, impregnating the carbon veil in the polyvinyl alcohol impregnating solution and drying the surface of the carbon veil Suppressing protrusion from the surface by binding the carbon fibers protruding from the Carbonization and graphitization to provide a carbon paper manufacturing method applied to a fuel cell gas diffusion layer comprising the step of burning the polyvinyl alcohol resin contained in the impregnated film of the carbon veil to form pores.

In addition, the polyvinyl alcohol impregnating solution provides a method for producing carbon paper applied to the fuel cell gas diffusion layer in which 5 to 10 parts by weight of the polyvinyl alcohol resin is dissolved based on 100 parts by weight of the polyvinyl alcohol impregnating solution.

In addition, the polyvinyl alcohol resin provides a method for producing carbon paper applied to a gas diffusion layer of a fuel cell having a molecular weight of 50,000 to 150,000.

In addition, the polyvinyl alcohol resin provides a method for producing carbon paper applied to a fuel cell gas diffusion layer having a saponification degree of 85 to 90 mol%.

Meanwhile, in another aspect of the present invention for solving the above-described problems, there is provided a carbon paper applied to a gas diffusion layer of a fuel cell manufactured using the above-described manufacturing method.

In addition, in another aspect of the present invention for solving the above-mentioned problems, it includes a carbon veil and a carbon structure bound on the carbon veil, and the carbon veil uses a polyvinyl alcohol impregnating solution, and carbon from the surface The protrusion of fibers is suppressed, and the carbon structure provides carbon paper applied to the fuel cell gas diffusion layer including pores formed by combustion of polyvinyl alcohol resin.

Carbon paper according to an embodiment of the present invention is carbon paper in which the protrusion of carbon fibers from the surface is suppressed by impregnating the carbon veil in the PVA impregnation solution in which the PVA resin is dissolved and binding the carbon fibers protruding from the surface of the carbon veil. can be manufactured, and for this reason, when applied to a fuel cell, it prevents the carbon fiber protruding from the surface from interfering with the membrane electrode assembly (at least one of a catalyst layer, an electrolyte layer, and a gas diffusion layer) in advance, thereby improving the durability of the fuel cell and performance can be easily obtained.

In addition, by controlling the concentration and molecular weight of the PVA resin impregnated in the carbon veil, pores are formed in the carbon paper produced through the carbonization and graphitization process, and the porosity can be increased to improve gas permeability, and through this, for fuel cells It is possible to increase the performance of the gas diffusion layer.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned may be clearly understood by those of ordinary skill in the art to which the present invention belongs from the following description. will be.

1 is a flowchart illustrating a method of manufacturing carbon paper according to an embodiment of the present invention.
2 is a cross-section of the carbon paper to which the process of impregnating the PVA impregnation solution according to Example 1 of the present invention is applied, taken with a scanning electron microscope (SEM).
3 is a cross-section of the carbon paper to which the process of impregnating the PVA impregnation solution according to Example 2 of the present invention is applied, taken by SEM.
4 is a cross-section of the carbon paper to which the process of impregnating the PVA impregnation solution according to Example 3 of the present invention is applied, taken by SEM.
5 is a cross-section of the carbon paper to which the process of impregnating the PVA impregnation solution according to Example 4 of the present invention is applied, taken by SEM.
6 is a cross-section of the carbon paper to which the process of impregnating the PVA impregnation solution according to Example 5 of the present invention is applied, taken by SEM.
7 is a cross-section of the carbon paper to which the process of impregnating the PVA impregnation solution according to Example 6 of the present invention is applied, taken by SEM.
8 is a cross-section of the carbon paper to which the process of impregnating the PVA impregnation solution according to Example 7 of the present invention is applied, taken by SEM.
9 is an SEM photograph of carbon paper excluding the process of impregnating the PVA impregnation solution according to Comparative Example 1 of the present invention.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

DETAILED DESCRIPTION The detailed description set forth below in conjunction with the appended drawings is intended to describe exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced.

In order to clearly explain the present invention in the drawings, parts not related to the description may be omitted, and the same reference numerals may be used for the same or similar components throughout the specification.

In an embodiment of the present invention, expressions such as “or” and “at least one” may indicate one of the words listed together, or a combination of two or more.

1 is a flowchart illustrating a method of manufacturing carbon paper according to an embodiment of the present invention.

Referring to Figure 1, the carbon paper according to an embodiment of the present invention, the step of preparing a PVA impregnation solution (S110), the step of impregnating the carbon veil in the PVA impregnation solution (S120), drying the impregnated carbon veil Manufacturing the carbon veil to which the PVA resin is bonded (S130), the step of impregnating the carbon veil to which the PVA resin is bonded in the phenol impregnation solution (S140), the step of drying and curing the impregnated carbon veil (S150), the cured It may include carbonizing the carbon veil (S160) and graphitizing the carbonized carbon veil (S170).

Here, the carbon veil can be manufactured through a wet-laid manufacturing process by dispersing carbon fibers in water, and the electrical properties can be improved only when the carbon fibers are well cultured in two dimensions.

Some carbon fibers protrude in the vertical direction on the surface of the carbon veil manufactured by the wet process. After coating the microporous layer without removing the protruding carbon fibers from the surface, a gas diffusion layer is prepared, and this is applied to the fuel cell. When applied, physical damage such as penetration of the membrane electrode assembly (at least one of a catalyst layer, an electrolyte layer, and a gas diffusion layer) by the protruding carbon fiber may occur, thereby reducing the durability and performance of the fuel cell. .

Carbon paper produced according to an embodiment of the present invention is formed so that the protrusion of the carbon fiber from the surface is suppressed by applying PVA resin to bind the carbon fiber protruding from the surface of the carbon veil, so that the carbon fiber protruding from the surface is It is possible to easily solve problems of deterioration in durability and performance of the fuel cell caused by interference with the membrane electrode assembly (at least one of a catalyst layer, an electrolyte layer, and a gas diffusion layer).

In addition, it is possible to increase the porosity of the carbon paper by controlling the concentration and molecular weight of the PVA resin, and thereby form a high gas permeability, which can be easily applied to increase the performance of the gas diffusion layer for fuel cells.

Specifically, in the step of preparing the PVA impregnation solution (S110), the PVA resin may be added to distilled water and stirred to prepare a PVA impregnation solution.

At this time, in this embodiment, applying the PVA resin having a molecular weight of 1,000 to 1,000,000 can bind the carbon fibers protruding from the surface of the carbon veil and suppress the protrusion of the carbon fibers, and preferably have a molecular weight of 50,000 to 150,000. By applying the PVA resin to the eggplant, it can cause an increase in gas permeability according to the formation of pores along with binding and improvement of carbon fibers protruding from the surface of the carbon veil.

In addition, since the PVA resin has a high melting point and is difficult to dissolve in water due to strong hydrogen bonding when the degree of saponification is high, it is preferable to apply a PVA resin having a degree of saponification of 85 to 90 mol% because of excellent solubility and PVA impregnation solution It can also be advantageous for manufacturing.

In the process of preparing the PVA impregnation solution, the PVA resin in powder form can be dissolved in distilled water. Preferably, it is easy to adjust the viscosity by dissolving the PVA resin in an amount of 1 to 30 parts by weight relative to 100 parts by weight of the PVA impregnation solution. Preferably, dissolving 5 to 10 parts by weight of the PVA resin relative to 100 parts by weight of the PVA impregnating solution may be advantageous in terms of manufacturing workability of the PVA impregnating solution, gas permeability due to pore formation, and penetration resistance.

Next, in the step of impregnating the carbon veil in the PVA impregnation solution (S120), the carbon veil made of carbon fibers is impregnated in the prepared PVA impregnation solution to bind the carbon fibers of the carbon veil through the PVA resin dissolved in the PVA impregnation solution. can

In addition, in the step of drying the impregnated carbon veil (S130), the carbon veil impregnated with the PVA impregnating liquid is dried for a few minutes to prepare the carbon veil to which the PVA resin is bonded.

At this time, as an example, the carbon veil impregnated with the PVA impregnating solution may be dried at 100° C. to 200° C. for several minutes to obtain a carbon veil bound to the PVA resin.

In this embodiment, the carbon veil is impregnated with PVA impregnating liquid and dried to bind the carbon fibers of the carbon veil through the PVA resin serving as a binder, thereby suppressing the carbon fibers protruding from the surface of the carbon veil to improve the flatness of the surface. This can increase the durability and performance of the fuel cell by solving the problem caused by the carbon fiber protruding from the surface.

In addition, the PVA resin impregnated into the carbon veil through the PVA impregnating liquid is burned in the carbonization and graphitization process of the carbon veil to be described later to form a number of pores in the impregnated film (carbon structure) of the carbon veil. may contribute to increasing the porosity of

At this time, by adjusting the concentration and molecular weight of the PVA resin impregnated in the carbon veil, the porosity formed in the impregnated film (carbon structure) can be increased, and thus the gas permeability can be improved.

As an example, as described above, when a PVA resin having a molecular weight of 50,000 to 150,000 is dissolved in an amount of 5 to 10 parts by weight relative to 100 parts by weight of the PVA impregnating solution, the increase in electrical resistance (penetration resistance) of carbon paper is suppressed. while increasing the gas permeability.

Next, in the step of impregnating the carbon veil in the phenol impregnation solution (S140), the carbon veil bound to the PVA resin may be impregnated in the phenol impregnation solution in which the phenol resin is dissolved.

Here, the phenol-impregnated liquid can be prepared by mixing ethanol, which is an alcohol-based solvent, a phenol resin, graphite powder, and aqueous polyurethane.

As an example, the phenol impregnating solution may be composed of 65 to 90 wt% of ethanol, 2 to 10 wt% of phenolic resin, 5 to 10 wt% of aqueous polyurethane, and 3 to 15 wt% of graphite powder.

Here, the phenol resin is a thermosetting resin used for manufacturing carbon paper, and has an advantage of high carbon yield after carbonization process.

These phenolic resins can be used by mixing one or more types that are soluble in alcohol, for example, at least one of a novolak-based or a resol-based resin can be selectively used.

In addition, aqueous polyurethane may be used as a thickener, and graphite powder may be used as a carbide to improve electrical conductivity.

Subsequently, in the step of drying and curing the impregnated carbon veil (S150), the remaining solvent may be dried in the first impregnated carbon veil, and the dried carbon veil may be cured.

In this case, preferably, the impregnated carbon bale may be dried at 70 to 100° C. for several minutes, and then cured at 150 to 200° C. for several minutes.

Next, in the step of carbonizing the cured carbon veil (S160), the cured carbon veil may be carbonized in an inert gas atmosphere.

Specifically, in order to block the combustion of the phenol resin, carbonization may be performed using nitrogen or argon gas, which is an inert gas, and preferably, carbonization may be performed at 700 to 900° C. for several tens of minutes.

Subsequently, in the step of graphitizing the carbonized carbon veil (S170), the carbonized carbon veil may be graphitized in an inert gas atmosphere.

In this case, the graphitization process may be performed using nitrogen gas or argon gas, and the temperature of the graphitization process may be formed at 2000° C. or higher.

As described above, the carbon paper according to this embodiment is made by impregnating the carbon veil in the PVA impregnating solution and binding the carbon fibers protruding from the surface of the carbon veil through the PVA resin serving as a binder, thereby providing carbon from the surface of the carbon veil. It can be formed to suppress the protrusion of fibers, and by impregnating the carbon veil bound with the PVA resin in the phenol impregnation solution, a uniform impregnation film can be formed on the surface.

In addition, in the process of carbonization and graphitization of the carbon veil, pores may be formed in the carbide (carbon structure) other than the carbon fibers included in the carbon veil. By forming pores in the carbide (carbon structure), it can contribute to the formation of pores.

In addition, depending on the concentration or molecular weight of the PVA resin impregnated in the carbon veil, the porosity of the produced carbon paper may be increased, and thus the gas permeability may be improved.

In particular, since the carbon paper according to the present embodiment is formed to suppress the protrusion of the carbon fiber from the surface, it is possible to solve problems such as deterioration in durability and performance of the fuel cell caused by the carbon fiber protruding from the surface.

Hereinafter, carbon paper prepared according to a preferred embodiment and a comparative example of the present invention will be described.

However, this is presented as a preferred example of the present invention and cannot be construed as limiting the present invention in any sense.

[Example 1]

1. PVA impregnation solution and carbon veil impregnation

5 g of PVA resin having a molecular weight of 32,000 to 47,000 was divided and added to 95 g of distilled water while stirring to prepare a PVA impregnating solution.

Next, the carbon veil containing carbon fibers having an average length of 9 mm was impregnated with the PVA impregnation solution, and then dried at 150° C. for 5 minutes to prepare a carbon bale bound to the PVA resin.

2. Impregnation with phenol impregnating solution

5 g of phenol resin, 8 g of graphite powder, 10 g of aqueous polyurethane, and 77 g of ethanol were weighed in a paste mixer container and stirred for 10 minutes under conditions of revolution of 1000 RPM and rotation of 1000 RPM to prepare a phenol impregnated solution.

Thereafter, the carbon veil bound with PVA resin was impregnated in the prepared phenol impregnation solution, and then the impregnated carbon bale was dried at 80° C. for 5 minutes, and cured at 180° C. for 5 minutes, and the cured carbon bale was dried in a nitrogen atmosphere. Carbon paper was prepared by carbonization at 900° C. for 1 hour and graphitization at 2000° C. for 1 hour.

[Example 2]

It was prepared in the same manner as in Example 1, but 5 g of a PVA resin having a molecular weight of 51,000 to 65,000 was divided into 95 g of distilled water to prepare a PVA impregnated solution, and carbon paper was prepared using this.

[Example 3]

It was prepared in the same manner as in Example 1, except that 5 g of PVA resin having a molecular weight of 136,000 to 150,000 was divided into 95 g of distilled water to prepare a PVA impregnated solution, and carbon paper was prepared using this.

[Example 4]

It was prepared in the same manner as in Example 1, except that 5 g of PVA resin having a molecular weight of 153,000 to 167,000 was divided into 95 g of distilled water to prepare a PVA impregnated solution, and carbon paper was prepared using this.

[Example 5]

It was prepared in the same manner as in Example 1, but 3 g of a PVA resin having a molecular weight of 51,000 to 65,000 was divided into 97 g of distilled water to prepare a PVA impregnated solution, and carbon paper was prepared using this.

[Example 6]

It was prepared in the same manner as in Example 1, but 10 g of a PVA resin having a molecular weight of 51,000 to 65,000 was divided into 90 g of distilled water to prepare a PVA impregnated solution, and carbon paper was prepared using this.

[Example 7]

It was prepared in the same manner as in Example 1, but 12 g of a PVA resin having a molecular weight of 51,000 to 65,000 was divided into 88 g of distilled water to prepare a PVA impregnated solution, and carbon paper was prepared using this.

[Comparative Example 1]

Carbon paper was prepared in the same manner as in Example 1, but without applying PVA resin.

The penetration resistance, gas permeability, and porosity of the carbon paper prepared according to Examples 1 to 7 and Comparative Example 1 were measured in the following manner.

1) Penetration resistance

The penetration resistance of the carbon paper was calculated by placing the sample between the upper and lower plates of the tester using CPRT-10 and compressing it, then measuring the electrical resistance at a pressure of 1 MPa and multiplying the measured sample area.

2) gas permeability

Gas permeability was measured using CPRT-10, and the upper plate of the tester was blocked and there was a hole through which gas was supplied in the center of the lower plate.

3) porosity

Porosity was measured using a mercury porosity analyzer (AutoPore V), filled with mercury in the sample and using the filled volume.

2 to 8 are photographs taken by SEM of the cross-section of the carbon paper according to Examples 1 to 7 of the present invention, respectively, and FIG. 9 is a cross-section of the carbon paper according to Comparative Example 1 of the present invention taken by SEM.

In addition, the results of measuring the penetration resistance, gas permeability, and porosity of the carbon paper prepared according to Examples 1 to 7 and Comparative Example 1 are shown in Table 1 below.

division PVA resin molecular weight PVA resin input ratio penetration resistance
(mΩ*cm2) Gas permeability (㎡) porosity
(%) Example 1 32,000-47,000 5 wt% 2.51

68 Example 2 51,000 to 65,000 5 wt% 2.59

77 Example 3 136,000~150,000 5 wt% 2.60

80 Example 4 153,000~167,000 5 wt% 2.91

85 Example 5 51,000 to 65,000 3wt% 2.49

69 Example 6 51,000 to 65,000 10wt% 2.58

80 Example 7 51,000 to 65,000 12wt% 2.8

83 Comparative Example 1 not put in - 2.48

65

2 to 8, in the case of the carbon paper according to the embodiment of the present invention, it can be confirmed that the protruding carbon fibers are not confirmed, and the surface of the carbon paper is formed flat.

On the other hand, referring to FIG. 9 , in the case of the carbon paper according to Comparative Example 1 of the present invention, a number of protruding carbon fibers are confirmed, and it can be confirmed that the surface of the carbon paper is not formed flat.

In addition, as shown in Table 1, in the case of the carbon paper according to the embodiment of the present invention, compared with Comparative Example 1, it can be confirmed that both the porosity and thus the gas permeability is increased.

On the other hand, the PVA impregnating solution of the present invention is preferably a PVA resin having a molecular weight of 50,000 to 150,000, based on 100 parts by weight of the PVA impregnating solution, 5 to 10 parts by weight of the dissolved PVA can be used.

As the molecular weight of the PVA resin in the PVA impregnation solution increases or the amount of the PVA resin input increases, the binding force between the carbon fibers increases, thereby suppressing the protrusion of the carbon fibers, and as the PVA resin is removed during the heat treatment process, the pores By being formed, the porosity and gas permeability may be increased, but if the pores are excessively large or formed excessively, the electrical resistance (penetration resistance) due to the formed pores may increase.

For this reason, it is necessary to maximize the gas permeability while suppressing the increase in electrical resistance (penetration resistance), which is 5 to 10 parts by weight of a PVA resin having a molecular weight of 50,000 to 150,000 based on 100 parts by weight of the PVA impregnating solution. This can be solved by using a PVA impregnating solution.

Referring to Table 1, Example 1, in which 5 parts by weight of PVA resin having a molecular weight of 32,000 to 47,000 was added, showed similar electrical resistance (penetration resistance) compared to Comparative Example 1 in which no PVA resin was added, while the porosity It can be seen that the gas permeability is increased.

In addition, in Example 2, in which 5 parts by weight of PVA resin having a molecular weight of 51,000 to 65,000 was added, electrical resistance (penetration resistance) was similar to that of Example 1, and porosity and gas permeability were significantly improved.

In addition, Example 3, in which 5 parts by weight of PVA resin having a molecular weight of 136,000 to 150,000 was added, showed similar electrical resistance (penetration resistance) as compared to Example 2, and improved porosity and gas permeability.

In addition, in Example 4, in which 5 parts by weight of PVA resin having a molecular weight of 153,000 to 167,000 was added, it can be confirmed that the porosity and gas permeability are improved compared to Example 3, but the electrical resistance (penetration resistance) is greatly increased can be checked

On the other hand, Example 5, in which 3 parts by weight of PVA resin having a molecular weight of 51,000 to 65,000 was added, showed similar electrical resistance (penetration resistance) compared to Comparative Example 1 in which PVA resin was not added, while porosity and gas permeability were increase can be seen.

In addition, in Example 2, in which 5 parts by weight of PVA resin having a molecular weight of 51,000 to 65,000 was added, electrical resistance (penetration resistance) was similar to that of Example 5, and porosity and gas permeability were significantly improved.

In addition, Example 6, in which 10 parts by weight of PVA resin having a molecular weight of 51,000 to 65,000 was added, showed similar electrical resistance (penetration resistance) as compared to Example 2, and improved porosity and gas permeability.

In addition, in Example 7, in which 12 parts by weight of PVA resin having a molecular weight of 51,000 to 65,000 was added, compared to Example 6, porosity and gas permeability were improved, but electrical resistance (penetration resistance) was significantly increased can be checked

As described above, in the carbon paper according to an embodiment of the present invention, the carbon veil is impregnated with the PVA impregnating liquid in which the PVA resin is dissolved to bind the carbon fibers protruding from the surface of the carbon veil, thereby forming the carbon fibers from the surface. Carbon paper formed to suppress protrusion can be manufactured. Accordingly, when applied to a fuel cell, the phenomenon in which the carbon fiber protruding from the surface interferes with the membrane electrode assembly (at least one of a catalyst layer, an electrolyte layer, and a gas diffusion layer) is prevented in advance. By preventing this, durability and performance of the fuel cell can be easily secured.

In addition, by controlling the concentration and molecular weight of the PVA resin impregnated in the carbon veil, pore formation and porosity can be increased in carbon paper produced through carbonization and graphitization processes, thereby improving gas permeability, preferably molecular weight By using a PVA impregnating liquid in which 5 to 10 parts by weight is added based on 100 parts by weight of 100 parts by weight of PVA impregnation solution of 50,000 to 150,000 PVA resin, it is possible to maximize gas permeability while suppressing an increase in electrical resistance (penetration resistance), and through this, fuel It is possible to increase the performance of the gas diffusion layer for a battery.

The embodiments of the present invention disclosed in the present specification and drawings are merely provided for specific examples in order to easily explain the technical contents of the present invention and help the understanding of the present invention, and are not intended to limit the scope of the present invention.

Therefore, the scope of the present invention should be construed as including all changes or modifications derived based on the technical spirit of the present invention in addition to the embodiments disclosed herein are included in the scope of the present invention.

Claims (9)

Dissolving a polyvinyl alcohol resin in water to prepare a polyvinyl alcohol impregnated solution;
impregnating the carbon veil in the polyvinyl alcohol impregnating solution and drying the carbon veil to bind the carbon fibers protruding from the surface of the carbon veil to inhibit protrusion from the surface;
impregnating the dried carbon veil in a phenol impregnating solution in which the phenol resin is dissolved;
drying and curing the impregnated carbon veil; and
Carbon paper manufacturing method applied to the fuel cell gas diffusion layer, comprising the step of carbonizing and graphitizing the cured carbon veil to form pores by burning the polyvinyl alcohol resin contained in the impregnated film of the carbon veil.
The method of claim 1,
The polyvinyl alcohol impregnated liquid,
5 to 10 parts by weight of the polyvinyl alcohol resin is dissolved based on 100 parts by weight of the polyvinyl alcohol impregnating solution, a method for producing carbon paper applied to a gas diffusion layer of a fuel cell.
The method of claim 1,
The polyvinyl alcohol resin is
A method for producing carbon paper applied to a gas diffusion layer of a fuel cell, having a molecular weight of 50,000 to 150,000.
The method of claim 1,
The polyvinyl alcohol resin is
A method for producing carbon paper applied to a gas diffusion layer of a fuel cell, wherein the degree of saponification is 85 to 90 mol%.
The carbon paper applied to the gas diffusion layer of a fuel cell, manufactured using any one of the manufacturing methods of any one of claims 1 to 4.
carbon veil; and
It includes a carbon structure bound on the carbon veil,
The carbon veil uses a polyvinyl alcohol-impregnated liquid to suppress the protrusion of carbon fibers from the surface, and the carbon structure includes pores formed by combustion of polyvinyl alcohol resin. Carbon applied to the fuel cell gas diffusion layer paper.
7. The method of claim 6,
The polyvinyl alcohol impregnated liquid,
Carbon paper applied to the fuel cell gas diffusion layer, in which 5 to 10 parts by weight of the polyvinyl alcohol resin is dissolved based on 100 parts by weight of the polyvinyl alcohol impregnating solution.
7. The method of claim 6,
The polyvinyl alcohol resin is
A carbon paper having a molecular weight of 50,000 to 150,000, applied to the fuel cell gas diffusion layer.
In the polyvinyl alcohol impregnating liquid for carbon paper applied to the gas diffusion layer of the fuel cell, comprising a carbon veil and a carbon structure bound to the carbon veil, and inhibiting the protrusion of carbon fibers from the surface of the carbon veil,
water; and
5 to 10 parts by weight based on 100 parts by weight of the polyvinyl alcohol impregnating solution contains a polyvinyl alcohol resin soluble in the water,
The polyvinyl alcohol impregnation solution for carbon paper applied to the fuel cell gas diffusion layer, wherein the polyvinyl alcohol resin is burned in the carbon structure to form pores, thereby increasing gas permeability.

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