Separator and manufacturing method therefor

Abstract

To provide a separator having good adhesion to a sealing member or another separator, and a manufacturing method for the separator, which can be produced without peeling off a carbon coating layer having good electrical conductivity.SOLUTION: The present invention relates to a separator including a separator substrate, a carbon coating layer formed on the surface of the separator substrate by a PVD method, and a styrene-based adhesive adhered to the carbon coating layer, and a manufacturing method therefor.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a separator, particularly a separator for a fuel cell and a method for manufacturing the separator.

Background Art

[0002] A fuel cell has a stack structure in which a predetermined number of single cells that generate electric power by the reaction of a fuel gas (hydrogen) and an oxidant gas (oxygen) are stacked. A single cell includes a membrane electrode assembly (MEA) having anode and cathode electrode layers (catalyst layers) on both sides of an electrolyte membrane, and gas diffusion layers (GDLs) (where GDL-MEA-GDL is referred to as a "membrane electrode gas diffusion layer assembly") optionally disposed on both sides of the membrane electrode assembly, and separators disposed on both sides of the membrane electrode assembly or the membrane electrode gas diffusion layer assembly, respectively.

[0003] The separator has a function of electrically connecting single cells in series and a function as a partition wall that blocks a fuel gas, an oxidant gas, and a cooling water from each other.

[0004] Generally, on one surface of the separator, a reaction gas flow path for flowing a reaction gas in a single cell is formed, and on the other surface, a cooling medium flow path for flowing a cooling medium in the single cell is formed. Further, at the peripheral portion of the separator, a reaction gas manifold opening that functions as an inlet and an outlet of the reaction gas and a cooling medium manifold opening that functions as an inlet and an outlet of the cooling medium flow path are formed. Furthermore, seal members for suppressing leakage of each fluid are appropriately provided around the reaction gas flow path, the cooling medium flow path, the reaction gas manifold opening, and the cooling medium manifold opening.

[0005] FIG. 1 schematically shows an example of a cross-sectional structure of a stack in which two fuel cells 9 are stacked. As shown in FIG. 1, the separator 3 is adhered to other members such as a resin frame 2 which is a seal member for suppressing leakage of fluids such as H2 and O2 which are reaction gases and cooling water which is a cooling medium, and GDL (for anode or cathode) 4, and further, it is necessary to adhere to a rubber gasket 1 for joining to a separator 3' of another fuel cell 9, that is, another separator 3'. Therefore, the adhesiveness between the separator and the adhesive used for adhesion to other members is an important factor in the characteristics of the separator.

[0006] For example, Patent Document 1 discloses a seal member for sealing the peripheral portions of a separator and a membrane electrode assembly of a polymer electrolyte fuel cell. The seal member is a seal member in which an adhesive layer is laminated and integrated on the surface of a main seal member portion made of foamed rubber. The foamed rubber is a foamed rubber obtained by blending a thermally expandable microcapsule into an uncrosslinked rubber material and expanding and crosslinking the rubber material by expanding the thermally expandable microcapsule. The adhesive layer is crosslinked by UV crosslinking and is crosslinked and adhered to the main seal member portion. A fuel cell seal member is disclosed.

[0007] Patent Document 2 discloses a fuel cell having a separator, wherein the separator has a surface that has been NC-treated, the peripheral portion of the separator has a larger amount of carbon black than the inner portion of the separator, and at least a part of the peripheral portion is adhered to a resin having a polar group. It is described that the adhesiveness between the separator and the adhesive can be adjusted by changing the amount of carbon black remaining on the surface of the separator applied by NC treatment.

[0008] Patent Document 3 discloses a method for manufacturing a fuel cell unit including a separator and a seal member adhered to the separator, the method including washing the separator with water, after the washing, irradiating the separator with ultraviolet light having an energy of 110 kcal / mol or more to remove moisture adhering to the separator, and after the ultraviolet light irradiation, adhering the separator to the seal member before moisture re - adheres to the separator.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0010] FIG. 2 schematically shows an example of the basic structure of a separator. The separator includes an electrode portion 10 for disposing a membrane - electrode assembly or a membrane - electrode gas diffusion layer assembly and a seal portion 11 for adhering other members (seal members). Usually, on the surface of the separator base material 12, in order to impart corrosion resistance to the separator, a corrosion - resistant coating, for example, a titanium coating is applied to form a titanium coating layer 13, and on the surface of the titanium coating layer 13, in order to impart conductivity to the separator, a conductive coating, for example, a carbon coating is applied to form a carbon coating layer 14. Methods of conductive coating include coating by a wet method and coating by a dry method.

[0011] From the perspective of forming a carbon coat layer having useful properties such as good electrical conductivity, hydrophobicity to prevent cooling water from penetrating, and peel resistance so as not to be easily peeled off, a coating by a dry method capable of forming a denser carbon coat layer 14, for example, carbon coating by a Physical Vapor Deposition (PVD) method, is preferable.

[0012] However, as shown in FIG. 2A, when the carbon coat layer 14 is formed on the entire surface of the separator substrate 12 and the titanium coat layer 13 using the PVD method, on the surface of the carbon coat layer 14, due to the characteristics of the PVD method, the number of polar functional groups decreases. As a result, the adhesiveness between the separator, particularly the carbon coat layer 14 on the separator surface, and an adhesive for adhering the coat layer 14 to a seal member, for example, an acrylic adhesive, becomes low.

[0013] Therefore, when a carbon coat layer 14 having excellent electrical conductivity, hydrophobicity, and peel resistance is formed on the surfaces of the separator substrate 12 and the titanium coat layer 13 using the PVD method, in order to adhere the separator and the adhesive, as shown in FIG. 2B, it is necessary to peel the carbon coat layer 14 (and in some cases, the titanium coat layer 13) at the location where the adhesive is adhered to the separator, which is time-consuming and costly.

[0014] Further, when adhering a seal member to the separator, for example, when using a rubber gasket as the seal member, in order to prepare the rubber gasket, a vulcanization process, that is, a process of adding a cross-linking agent to the raw material of the rubber and heating to form a network structure, is required during rubber molding, which is also time-consuming and costly.

[0015] Therefore, an object of the present invention is to provide a separator having good adhesiveness to a seal member or another separator, and a method for manufacturing the separator capable of manufacturing the separator with a carbon coat layer having good electrical conductivity without peeling.

Means for Solving the Problem

[0016] As a result of various studies on means for solving the above problems, the present inventors have found that in a separator substrate having a carbon coating on its surface by a PVD method, when a sheet-like styrene-based adhesive is disposed at a location where the performance as a seal member is required, the adhesiveness between the separator and the adhesive is improved, and further, the styrene-based adhesive also acts as a seal member, thus completing the present invention.

[0017] That is, the gist of the present invention is as follows. (1) A separator substrate, A carbon coating layer formed on the surface of the separator substrate, A styrene-based adhesive adhered on the carbon coating layer, and comprising, the surface of the carbon coating layer having an oxygen ratio of 6 atom% (atomic percent) or less when measured by X-ray photoelectron spectroscopy (XPS), a separator. (2) The separator according to (1), wherein the styrene-based adhesive is selected from a copolymer having a polymer block of a styrene monomer and a (co)polymer block of one or more aliphatic monoolefins and / or one or more aliphatic conjugated diolefins or a partially or fully hydrogenated body block thereof, or a mixture of two or more thereof. (3) The separator according to (1) or (2), wherein the styrene-based adhesive is in a sheet form. (4) (i) A step of forming a carbon coating layer by applying a carbon coating to the surface of a separator substrate by a PVD method, and (ii) A step of disposing a styrene-based adhesive on the carbon coating layer formed in the step (i), and a method for manufacturing a separator, including. (5) The method for manufacturing a separator according to (4), wherein in the step (i), the PVD method is a filterless arc ion plating (AIP) method. The method for manufacturing the separator according to (4) or (5), wherein in the step of (6)(ii), the styrene-based pressure-sensitive adhesive is selected from a copolymer having a polymer block of styrene monomer and a (co)polymer block of one or more aliphatic monoolefins and / or one or more aliphatic conjugated diolefins or a partial or fully hydrogenated body block thereof, or a mixture of two or more thereof. The method for manufacturing the separator according to any one of (4) to (6), wherein in the step of (7)(ii), the styrene-based pressure-sensitive adhesive is in a sheet form.

Advantages of the Invention

[0018] The present invention provides a separator having good adhesiveness to a seal member or another separator, and a method for manufacturing the separator capable of manufacturing the separator without peeling a carbon coat layer having good conductivity.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0020] Hereinafter, preferred embodiments of the present invention will be described in detail. In this specification, the features of the present invention will be described with reference to the drawings as appropriate. In the drawings, the dimensions and shapes of each part are exaggerated for clarity and do not accurately depict the actual dimensions and shapes. Therefore, the technical scope of the present invention is not limited to the dimensions and shapes of each part shown in these drawings. Note that the separator of the present invention and its manufacturing method are not limited to the following embodiments, and can be implemented in various forms with modifications and improvements that can be made by those skilled in the art without departing from the gist of the present invention.

[0021] The present invention relates to a separator including a separator substrate, a carbon coating layer formed on the surface of the separator substrate, and a styrene-based adhesive adhered on the carbon coating layer, wherein the surface of the carbon coating layer has an oxygen ratio of 6 atom% or less when measured by X-ray photoelectron spectroscopy (XPS).

[0022] In the present invention, the separator is a component of a fuel cell (single cell), and is disposed on both sides of a membrane electrode assembly (an electrolyte membrane, electrode layers of an anode and a cathode disposed on both sides of the electrolyte membrane) or a membrane electrode gas diffusion layer assembly (membrane electrode assembly, gas diffusion layers disposed on both sides of the membrane electrode assembly).

[0023] As the separator substrate, a metal substrate known in the art can be used. For example, but not limited to, titanium, stainless steel (SUS) (an alloy of iron, chromium, and nickel), for example, a plate made of a metal (including alloys) such as SUS304 can be used.

[0024] By selecting stainless steel as the separator substrate, the raw material cost can be suppressed.

[0025] The thickness of the separator substrate is not limited, but in terms of the average thickness, it is usually 0.05 mm to 0.5 mm, preferably 0.08 mm to 0.2 mm.

[0026] By making the thickness of the separator base material within the above range, the raw material cost can be suppressed.

[0027] The separator base material usually has an uneven shape for delivering fluids such as H2 and O2 which are reaction gases, and cooling water which is a cooling medium. The difference in unevenness in the uneven shape of the separator base material is usually 5 μm to 50 μm excluding the thickness of the separator base material. In the separator of the present invention, since the thickness of the carbon coating layer (and optionally the titanium coating layer) formed on the separator base material is thin compared to the thickness of the separator base material, the shape of the separator depends on the uneven shape of the separator base material.

[0028] The separator base material may be titanium-coated to improve corrosion resistance.

[0029] The thickness of the titanium coating layer on the separator base material is not limited, but in terms of the average thickness, it is usually 20 nm to 500 nm, preferably 150 nm to 300 nm. The average thickness of the titanium coating layer can be measured, for example, by cross-sectional TEM observation.

[0030] By setting the upper limit of the thickness of the titanium coating layer as described above, the effect of reducing the amount of titanium used can be obtained, and it is possible to prevent the film stress generated by the formation of the titanium coating layer from becoming too large, and to suppress the occurrence of cracks in the titanium coating layer and the deformation of the base material on which the titanium coating layer is laminated, for example, the separator base material on which the titanium coating layer is laminated.

[0031] By setting the lower limit of the thickness of the titanium coating layer as described above, sufficient corrosion resistance can be ensured.

[0032] In the separator of the present invention, the thickness of the carbon coating layer formed on the separator base material and optionally on the titanium coating layer formed on the surface of the separator base material is not limited, but in terms of the average thickness, it is usually 10 nm to 200 nm, preferably 50 nm to 150 nm. The average thickness of the carbon layer can be measured, for example, by cross-sectional TEM observation.

[0033] Here, the carbon coating layer in the present invention is a carbon coating layer formed by the PVD method, and the surface of the carbon coating layer has an oxygen ratio of 6 atom% or less when measured by X-ray photoelectron spectroscopy (XPS).

[0034] By setting the thickness of the carbon coating layer formed on the separator substrate and, optionally, on the titanium coating layer formed on the surface of the separator substrate within the above range, low contact resistance, that is, high conductivity can be ensured.

[0035] In the separator of the present invention, a styrene-based adhesive is adhered to a portion where adhesion to other members such as a resin frame or gasket, which are seal members for suppressing leakage of fluids such as H2 and O2 as reaction gases and cooling water as a cooling medium, or another separator is required, above the carbon coating layer.

[0036] Here, the adhesive is a type of pressure-sensitive adhesive. While a normal adhesive becomes a liquid, spreads by wetting, and then cures and adheres, the adhesive has the property of spreading and adhering while remaining solid by applying pressure, usually a pressure of 0.5 MPa to 3 MPa.

[0037] A styrene-based pressure-sensitive adhesive is a copolymer having a polymer block of a styrene monomer and a (co)polymer block of one or more aliphatic monoolefins and / or one or more aliphatic conjugated diolefins, or a partially or fully hydrogenated block thereof, or a mixture of two or more thereof. Here, examples of the polymer block of the styrene monomer include styrene, α-methylstyrene, 4-methylstyrene, 4-t-butylstyrene, 4-vinylstyrene, 1,1-diphenylethylene, 1,1-dimethyl-p-aminoethylstyrene, and the like. Examples of the aliphatic monoolefin include ethylene, propylene, 1-butene, 2-butene, 2-methyl-1-propene, 1-pentene, 2-pentene, 2-methyl-1-butene, 2-methyl-2-butene, 3-methyl-1-butene, 1-hexene, 2-hexene, 3-hexene, 2-methyl-1-pentene, 2-methyl-2-pentene, 4-methyl-1-pentene, 4-methyl-2-pentene, n-heptene, isoheptene, n-octene, isooctene, n-nonene, isooctene, n-decene, isodecene, and the like. Examples of the aliphatic conjugated diolefin include 1,3-butadiene, 2-methyl-1,3-butadiene, and the like.

[0038] Conventionally, acrylic pressure-sensitive adhesives have been considered to have better adhesion (tack) than styrene-based pressure-sensitive adhesives. Therefore, in the severe environment of fuel cells, in order to ensure sufficient sealing performance, acrylic pressure-sensitive adhesives having better tack have often been selected. However, in the present invention, by adhering a styrene-based pressure-sensitive adhesive instead of an acrylic pressure-sensitive adhesive onto the carbon coating layer, the adhesiveness and hydrophobicity with the carbon coating layer can be improved compared to the case where a conventional acrylic pressure-sensitive adhesive is adhered, and as a result, when adhering the styrene-based pressure-sensitive adhesive to a seal member or another separator, good adhesiveness and seal reliability can be ensured.

[0039] The styrene-based pressure-sensitive adhesive is preferably in the form of a sheet.

[0040] Since the styrene-based adhesive is in the form of a sheet, it becomes easier to dispose the styrene-based adhesive on the separator during the manufacture of the separator. Further, the styrene-based adhesive itself can serve as a sealing member. As a result, the adhesion between the separators can be smoothly carried out more easily than using a rubber gasket or the like as the sealing member, reducing the number of steps, time, and cost.

[0041] The separator in the present invention is adhered to components of a fuel cell known in the art, such as a membrane electrode assembly or a membrane electrode gas diffusion layer assembly, to manufacture a fuel cell.

[0042] A fuel cell manufactured using the separator for a fuel cell in the present invention can be used in various electrochemical devices such as a polymer electrolyte fuel cell.

[0043] Therefore, since the adhesion between the carbon coat layer on the separator substrate and the styrene-based adhesive in the separator of the present invention is sufficiently strong, for example, the operating temperature range is usually -35°C to 120°C, the types of gases used are hydrogen (H2) and air, the pressure of the gases used is usually 0 kPa·G to 550 kPa·G, the cooling water is an ethylene glycol solution, and it can be used in various electrochemical devices in an environment where it comes into contact with a sulfuric acid solution (pH of about 3) as the generated water.

[0044] FIG. 3 schematically shows an example of a cross-sectional structure of a stack in which two fuel cells 9 including the separator of the present invention are stacked. As shown in FIG. 3, the separator 3 of the present invention includes a resin frame 2 which is a sealing member for suppressing leakage of fluids such as H2 and O2 which are reaction gases and cooling water which is a cooling medium, and a sheet-like styrene-based adhesive S for adhering to other members such as a GDL (for anode or cathode) 4 and / or joining to a separator 3' provided in another fuel cell 9.

[0045] The separator of the present invention can be manufactured by a method for manufacturing a separator, which includes: (i) a step of forming a carbon coating layer by applying a carbon coating on the surface of a separator base material by a PVD method; and (ii) a step of disposing a styrene-based adhesive on the carbon coating layer formed in the step (i).

[0046] (i) A step of forming a carbon coating layer by applying a carbon coating on the surface of a separator base material by a PVD method In the step (i), a carbon coating layer is formed by applying a carbon coating on the surface of a separator base material by a PVD method.

[0047] As the separator base material, the above-described separator base material can be used, and a titanium coating layer may be formed on the surface of the separator base material, that is, on the surface where the carbon coating is applied.

[0048] As a method for forming a titanium coating layer on the surface of the separator base material, a method known in the art can be used, and examples include, but are not limited to, a sputtering method which is a kind of physical vapor deposition method, for example, an unbalanced magnetron sputtering (UBMS) method.

[0049] The conditions for carbon coating by the PVD method for forming a carbon coating layer on the surface of the separator base material or on the titanium coating layer formed on the surface of the separator base material can be conditions known in the art and are not limited.

[0050] For example, as the PVD method, a filterless arc ion plating (AIP) method can be used.

[0051] Here, the AIP method is a method in which an ionized substance (which is the evaporated and ionized target, hereinafter referred to as the ionized evaporated substance) generated by arc discharge generated between the target constituting the anode and the cathode is accelerated by applying a bias voltage to the separator substrate, and the ionized evaporated substance is formed into a film on the separator substrate.

[0052] The bias voltage in the AIP method is not limited and can be adjusted so that a carbon layer with a denser and lower contact resistance is formed.

[0053] Regarding the AIP method, for example, the initial vacuum degree in the apparatus chamber, the cleaning conditions of the separator substrate surface (for example, the conditions of argon bombardment treatment), the conditions of the gas for plasma generation, the film formation time, the film formation temperature, etc. can be the conditions known in the technical field (for example, refer to Japanese Patent Laid-Open No. 2008-204876). Since the film thickness increases as the film formation time becomes longer, a desired film thickness can be obtained by adjusting the film formation time.

[0054] (ii) A step of disposing a styrene-based adhesive on the carbon coat layer formed in the step (i) In the step (ii), a styrene-based adhesive is disposed at a location where adhesion to other members such as a seal member on the carbon coat layer formed in the step (i) or another separator is required.

[0055] As the styrene-based adhesive, the styrene-based adhesive described above is used.

[0056] Conventionally, acrylic adhesives were considered to have superior adhesive strength (tack) compared to styrene adhesives. Therefore, in the harsh environment of fuel cells, in order to ensure sufficient sealing performance, acrylic adhesives with more excellent tack were often selected. However, in the present invention, by adhering a styrene adhesive, rather than an acrylic adhesive, onto the carbon coating layer, the adhesiveness and hydrophobicity with the carbon coating layer can be improved compared to the case of adhering a conventional acrylic adhesive. As a result, when adhering the styrene adhesive to a seal member or another separator, good adhesiveness and seal reliability can be ensured.

[0057] The styrene adhesive is preferably in the form of a sheet.

[0058] Since the styrene adhesive is in the form of a sheet, the placement of the styrene adhesive onto the separator during separator manufacturing becomes easy. Furthermore, the styrene adhesive itself can serve as a seal member. As a result, the adhesion between separators can be smoothly carried out more easily than using a rubber gasket or the like as a seal member, reducing the number of steps and the time and cost.

Examples

[0059] Hereinafter, several examples related to the present invention will be described, but the present invention is not intended to be limited to those shown in such examples.

[0060] 1. Manufacture of separator Comparative Example 1 (i) A separator substrate (SUS304) was prepared. (ii) A separator was manufactured by placing a sheet-like styrene adhesive (an adhesive containing a styrene-isobutene copolymer) on the surface of the separator substrate prepared in step (i).

[0061] Comparative Example 2 (i) A titanium coating layer was formed by applying a titanium coating on the surface of a separator base material (SUS304). Further, a carbon coating layer (surface oxygen ratio by XPS: 6 atomic % or less) was formed by applying a carbon coating by PVD method on the titanium coating layer. The details of the PVD method were as described in Table 1.

[0062]

Table 1

[0063] (ii) A separator was manufactured by placing a sheet-like acrylic adhesive (an adhesive containing butyl acrylate) on the carbon coating layer formed in the step (i).

[0064] Example 1 A separator was manufactured in the same manner as Comparative Example 2, except that in the step (ii) of Comparative Example 2, a sheet-like styrene-based adhesive (an adhesive containing a styrene-isobutene copolymer) was placed instead of the sheet-like acrylic adhesive.

[0065] 2. Adhesion evaluation of the separator Regarding the separators of Comparative Examples 1 and 2 and Example 1, the peel strength (adhesive force) between the separator base material or carbon coating layer of each separator and the adhesive was measured. The adhesive force was measured by the method shown in FIG. 4, that is, by measuring the force required to peel each adhesive 15 from the separator 3 to the opposite side by 180°.

[0066] FIG. 5 shows the results of the adhesive force of the adhesives in the separators of Comparative Example 1 and Example 1.

[0067] From FIG. 5, it was found that the peel strength between the carbon coating layer of Example 1 and the styrene-based adhesive was about 1.5 times that between the separator base material of Comparative Example 1 and the styrene-based adhesive.

[0068] Generally, when trying to develop an adhesive having an adhesive force 1.5 times that of its initial strength for a certain adhesive, it is often necessary to sacrifice other properties of the adhesive, such as heat resistance and durability. By comparing Comparative Example 1 and Example 1, it was found that by simply using a separator with a carbon coating layer formed on its surface by the PVD method as the separator, an adhesive force of about 1.5 times can be achieved without improving the adhesive itself. Therefore, it was found that carbon coating by the PVD method on the separator substrate is very useful for styrene-based adhesives.

[0069] Fig. 6 shows the results of the adhesive force of the adhesives in the separators of Comparative Example 2 and Example 1 initially and after immersion for FCC 500 hours (hr). Here, after immersion for FCC 500 hr means after immersing the separator of Comparative Example 2 or Example 1 in FCC (coolant in a fuel cell vehicle) at 120 °C for 500 hours.

[0070] From Fig. 6, the peel strength between the carbon coating layer of Example 1 and the styrene-based adhesive was about 2 times that of the peel strength between the carbon coating layer of Comparative Example 2 and the acrylic-based adhesive initially. Therefore, it was found that for a separator with a carbon coating layer formed on its surface by the PVD method, the styrene-based adhesive has a stronger adhesive force than the acrylic-based adhesive. Furthermore, the peel strength between the carbon coating layer of Example 1 and the styrene-based adhesive increased to about 8 times that of the peel strength between the carbon coating layer of Comparative Example 2 and the acrylic-based adhesive after immersion for FCC 500 hours. Note that the peel strength between the carbon coating layer of Example 1 and the styrene-based adhesive hardly changed before and after immersion for FCC 500 hours. Therefore, it was found that for a separator with a carbon coating layer formed on its surface by the PVD method, the styrene-based adhesive has better durability than the acrylic-based adhesive.

Description of reference numerals

[0071] 1. Rubber gasket, 2. Resin frame, 3. Separator, 3’. Another separator, 4. GDL, 5. Electrode layer, 6. Electrolyte membrane, 7. MEA, 8. Membrane electrode gas diffusion layer assembly, 9. Fuel cell, 10. Electrode part, 11. Seal part, 12. Separator base material, 13. Titanium coating layer, 14. Carbon coating layer, 15. Adhesive, S. Sheet-like styrene-based adhesive

Claims

1. A separator substrate, a carbon coating layer formed on the surface of the separator substrate, and a styrene-based pressure-sensitive adhesive adhered to the carbon coating layer are provided, wherein the surface of the carbon coating layer has an oxygen ratio of 6 atomic % or less when measured by X-ray photoelectron spectroscopy separator.

2. The separator according to claim 1, wherein the styrene-based pressure-sensitive adhesive is selected from a copolymer having a polymer block of a styrene monomer and a (co)polymer block of one or more aliphatic monoolefins and / or one or more aliphatic conjugated diolefins or a partially or fully hydrogenated block thereof, or a mixture of two or more thereof.

3. The separator according to claim 1 or 2, wherein the styrene-based pressure-sensitive adhesive is in a sheet form.

4. (i) a step of forming a carbon coating layer by applying a carbon coating to the surface of the separator substrate by a PVD method; and (ii) a step of disposing a styrene-based pressure-sensitive adhesive on the carbon coating layer formed in the step (i) are included, which is a method for manufacturing a separator.

5. The method for manufacturing a separator according to claim 4, wherein in the step (i), the PVD method is a filterless arc ion plating (AIP) method.

6. The method for manufacturing a separator according to claim 4 or 5, wherein in the step (ii), the styrene-based pressure-sensitive adhesive is selected from a copolymer having a polymer block of a styrene monomer and a (co)polymer block of one or more aliphatic monoolefins and / or one or more aliphatic conjugated diolefins or a partially or fully hydrogenated block thereof, or a mixture of two or more thereof.

7. The method for manufacturing a separator according to claim 4 or 5, wherein in the step (ii), the styrene-based pressure-sensitive adhesive is in a sheet form.

8. The method for manufacturing a separator according to claim 6, wherein in the step (ii), the styrene-based pressure-sensitive adhesive is in a sheet form.

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