WO2016105097A1

WO2016105097A1 - Composite material for fuel cell separator plate, fuel cell separator plate and method for preparing same

Info

Publication number: WO2016105097A1
Application number: PCT/KR2015/014122
Authority: WO
Inventors: 오애리; 박종성; 최한나; 김희준
Original assignee: (주)엘지하우시스
Priority date: 2014-12-24
Filing date: 2015-12-22
Publication date: 2016-06-30
Also published as: KR101932424B1; KR20160078687A

Abstract

Provided are a composite material for a fuel cell separator plate and a fuel cell separator plate formed from one or more of the composite materials for a fuel cell separator plate, the composite material comprising: a first continuous conductive fiber bundle aligned in one direction and an impregnation resin; and a plurality of layers, one layer being the first continuous conductive fiber bundle aligned in one direction.

Description

Composite material for fuel cell separator, fuel cell separator and manufacturing method

A composite material for a fuel cell separator, a fuel cell separator, and a method of manufacturing the same.

A fuel cell is a power generation system that generates electricity by an electrochemical reaction between hydrogen and oxygen. The fuel cell may include a stack, which is a main component for producing electricity directly, and other devices that assist the operation of the stack.

The fuel cell stack includes a unit cell as a minimum unit for generating silver electrical energy, and the unit cell includes a membrane electrode assembly (MEA) and fuel provided on both sides of the membrane electrode assembly. Battery separators may be included.

The membrane electrode assembly includes a polymer electrolyte membrane for selectively passing only hydrogen ions, and an anode electrode and a cathode electrode may be bonded to both sides of the polymer electrolyte membrane.

The fuel cell separator serves to collect current generated from the unit cell, to separate insulation to maintain insulation, and to discharge water generated by supplying gas (hydrogen and oxygen) to a gas diffusion layer (GDL). It can play a role.

Such a fuel cell separator must be stable in the oxidation / reduction atmosphere of the anode electrode and the cathode electrode, sufficiently prevent gas mixing, and have sufficient electrical conductivity.

Conventional commercially available graphite separators have corrosion resistance and good electrical conductivity, but are weak against mechanical shock or vibration, and thus have to maintain a certain thickness or more, which reduces the efficiency of the fuel cell stack and has a high cost problem. There is a problem of gas permeability.

In one embodiment of the present invention, there is provided a composite for a fuel cell separator that implements excellent processability, excellent productivity, excellent molding processability, excellent corrosion resistance, low contact resistance and excellent electrical conductivity.

In another embodiment of the present invention, there is provided a fuel cell separator formed by the fuel cell separator composite.

In another embodiment of the present invention, a method of manufacturing the fuel cell separator is provided.

However, the technical problem to be achieved by the present invention is not limited to the above-mentioned problem, another task that is not mentioned will be clearly understood by those skilled in the art from the following description.

In one embodiment of the present invention, comprising a first conductive continuous fiber bundle and an impregnation resin aligned in one direction, comprising a plurality of layers of the first conductive continuous fiber bundle aligned in one direction as one layer Provided is a composite material for a fuel cell separator.

The plurality of layers may be parallel to each other.

When the at least one fuel cell separator is formed of a fuel cell separator, both end faces of the first conductive continuous fiber bundle may be exposed to the top and bottom surfaces of the fuel cell separator, respectively. have.

Wherein the composite material for fuel cell separator comprises two surfaces each of which both end surfaces of the first conductive continuous fiber bundle is exposed and the side surface therebetween, wherein the plurality of composite material for fuel cell separator is formed of a fuel cell separator plate It may be attached to the side.

When the at least one composite for fuel cell separator is formed of a fuel cell separator, the longitudinal direction of the first conductive continuous fiber bundle may be perpendicular to the top and bottom surfaces of the fuel cell separator.

The composite material for the fuel cell separator may not separately include a conductive filler.

The length of the first conductive continuous fiber bundle may be about 0.1mm to about 2.0mm.

The first conductive continuous fiber bundle is a fiber filament, for example, the first conductive continuous fiber is formed by converging, for example, about 1,000 to about 48,000 strands, the thickness of the first conductive continuous fiber bundle is about 0.1mm to about 0.2 mm and may have a width of about 1.0 mm to about 20.0 mm.

The linear density of the first conductive continuous fiber may be about 800 g / km to about 4,000 g / km.

The weight ratio of the impregnating resin to the first conductive continuous fiber bundle may be about 1:40 to about 1:99.

And from about 1 to about 100 layers.

The thickness in the direction perpendicular to the layer may be about 0.12 mm to about 22.0 mm.

The width in the direction parallel to the layer and perpendicular to the longitudinal direction of the first conductive continuous fiber bundle may be about 25.0 mm to about 100.0 mm.

The first conductive continuous fiber may include an organic fiber, an inorganic fiber, or both of which the surface of the fiber is coated with the conductive filler, or the conductive filler is dispersed and contained in the fiber.

The layer may further or may not include a second conductive continuous fiber bundle aligned in a direction different from the one direction.

In another embodiment of the present invention, formed by at least one composite for fuel cell separator, both end faces of the first conductive continuous fiber bundle may be exposed on the upper and lower surfaces, respectively.

The fuel cell separation plate composite includes two surfaces each of which both end surfaces of the first conductive continuous fiber bundle are exposed and side surfaces therebetween, and a plurality of fuel cell separation plate composites are attached to the side surfaces by thermocompression bonding. Can be molded.

The length direction of the first conductive continuous fiber bundle may be perpendicular to the upper surface and the lower surface of the fuel cell separator.

The total thickness of the fuel cell separator may be about 0.1 mm to about 2.0 mm.

The contact resistance of the fuel cell separator may be about 20 mΩ · cm ² or less, and the electrical conductivity may be about 100 S / cm to about 200 S / cm.

In addition, the flexural strength of the fuel cell separator may be about 94 MPa to about 400 MPa.

In another embodiment of the present invention, forming a first conductive continuous fiber bundle sheet; After stacking the plurality of first conductive continuous fiber bundle sheets, immersion and drying are performed on the impregnated resin, or the first conductive continuous fiber bundle sheets and the impregnated resin films are alternately laminated, and then thermocompression bonding is performed. Forming a preliminary composite; Cutting the preliminary composite material perpendicularly to the longitudinal direction of the first conductive continuous fiber bundle at regular intervals within a range of 0.1 mm to 2.0 mm to form a composite material for a fuel cell separator; And manufacturing a fuel cell separator such that both end faces of the first conductive continuous fiber bundle are exposed on the top and bottom surfaces of the fuel cell separator using the at least one composite for fuel cell separator. It provides a method for manufacturing a fuel cell separator comprising a.

The fuel cell separator and the fuel cell separator may realize excellent processability, excellent productivity, excellent molding processability, excellent corrosion resistance, low contact resistance, and excellent electrical conductivity.

1 is a schematic perspective view of a fuel cell separator composite according to one embodiment of the present invention.

2 is a schematic perspective view of a fuel cell separator according to another embodiment of the present invention.

3 is a schematic process flow diagram of a fuel cell separator according to another embodiment of the present invention.

FIG. 4 is a schematic diagram illustrating a step S1 in the process flowchart of FIG. 3.

FIG. 5 is a schematic diagram illustrating a second step S2 in the process flow diagram of FIG. 3.

FIG. 6 is a schematic diagram illustrating the third step S3 in the process flow diagram of FIG. 3.

FIG. 7 is a schematic diagram illustrating the four steps S4 in the process flow diagram of FIG. 3.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

In order to clearly describe the present invention, parts irrelevant to the description are omitted, and like reference numerals designate like elements throughout the specification.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. In the drawings, the thicknesses of layers and regions are exaggerated for clarity.

In the following, any configuration is formed on the top (or bottom) of the substrate or on the top (or bottom) of the substrate, not only means that the arbitrary configuration is formed in contact with the top (or bottom) of the substrate, but also the substrate It is not limited to not including other configurations between and any configuration formed on (or under) the substrate.

In one embodiment of the present invention, comprising a first conductive continuous fiber bundle and an impregnation resin aligned in one direction, comprising a plurality of layers of the first conductive continuous fiber bundle aligned in one direction as one layer Provided is a composite material for a fuel cell separator. FIG. 1 schematically shows a perspective view of the composite material 100 for a fuel cell separator, and as shown in FIG. 1, formed of a first conductive continuous fiber bundle 110 aligned in one direction in the impregnation resin 120. A plurality of layers may be included.

The first conductive continuous fiber bundle 110 aligned in one direction may be aligned in one direction on a single plane and the neighboring first conductive continuous fiber bundles 110 may be partially or totally in close contact, for example, as a sheet. The first conductive continuous fiber bundle 110 sheet may be formed as one layer. That is, a plurality of sheets of the first conductive continuous fiber bundle 110 may be included in the impregnation resin 120.

Specifically, the plurality of layers may be parallel to each other, and thus, the first conductive continuous fiber bundle 110 may be aligned in the one direction in the impregnating resin 120.

Recently, a polymer composite separator including a polymer resin and a conductive fiber has been used, but in order to satisfy the required electric and thermal conductivity, the polymer composite separator additionally adds a large amount of conductive fillers in addition to the conductive fiber. As the process becomes complicated, time and cost are further consumed, the productivity is low, and when the conductive filler is contained in a large amount, there is a problem in that moldability is reduced. In addition, when conductive fibers or conductive fillers are unevenly dispersed in the fuel cell separator, the flow of current becomes uneven and the flow of current may be partially interrupted by the polymer resin having insulation performance, resulting in contact resistance. As it increases, the electrical conductivity may decrease.

Thus, in one embodiment of the present invention, the fuel cell separator composite material 100 includes a first conductive continuous fiber bundle 110 and the impregnation resin 120 aligned in one direction, as will be described later, the fuel In the case of forming the battery separator, the longitudinal direction L of the first conductive continuous fiber bundle 110 aligned in one direction may be applied to be perpendicular to the upper and lower surfaces of the separator, thereby separating the fuel cell. In the plate, the longitudinal direction L of the first conductive continuous fiber bundle 110 may be formed in the same direction as the current flow direction. Accordingly, since the current may flow along the first conductive continuous fiber bundle 110 when the fuel cell including the separator manufactured by the composite material for the fuel cell separator 100 may flow, the current flows uniformly. The interruption of the flow of current can be effectively prevented.

As a result, the fuel cell separator composite material 100 is not formed of a metal material, which is excellent in corrosion resistance, and does not include a large amount of conductive fillers, thereby providing excellent processability, productivity, and molding processability, and at the same time, flow of current The more uniform and can be prevented disconnection has the advantage of achieving low contact resistance and excellent electrical conductivity.

In the present specification, the upper and lower surfaces of the fuel cell separator are a pair of surfaces contacting the gas diffusion layer, the membrane electrode assembly, and the like in the fuel cell or the unit cell, and mean a pair of surfaces perpendicular to the current flow direction. . The fuel cell separator does not need to be divided into upper and lower surfaces in a symmetrical form, but for convenience of description, the fuel cell separator is referred to as an upper surface and a lower surface. It may be arbitrarily selected and is not particularly limited.

In addition, the first conductive continuous fiber bundle 110 may also be referred to as a fiber concentrator, and may be formed by concentrating the first conductive continuous fiber, for example, 1,000 to 48,000 strands as a fiber filament. The fiber filament may include a monofilament, a multifilament or both thereof, and the monofilament may mean a thread formed of one ol, and the multifilament may mean a thread formed by twisting a plurality of ol.

The first conductive continuous fibers may be formed by, for example, depositing them in a binder resin-containing composition or spraying and converging a binder resin-containing composition thereon to form the first conductive continuous fiber bundle 110.

The binder resin may be a kind known in the art, for example, acrylic resin, methacryl resin, polyisoprene, vinyl resin, epoxy resin, urethane resin, cellulose resin and combinations thereof It may include at least one selected from the group containing, but is not limited thereto.

The first conductive continuous fiber bundle 110 may include an organic fiber, an inorganic fiber, or both of which the surface of the continuous fiber bundle is coated with a conductive filler or a conductive filler is dispersed in the continuous fiber bundle. Thus, current can easily flow along these fibers.

The organic fibers include, for example, synthetic fibers such as polypropylene fibers, aramid fibers, and the like, and the inorganic fibers include, for example, glass fibers, carbon fibers, ceramic fibers, and the like.

Specifically, the first conductive continuous fiber bundle 110 is a fan (PAN) -based, pitch-based and Rayon-based carbon fibers; Carbon nanofibers; Activated carbon fibers; And at least one selected from the group consisting of a combination thereof.

In addition, the carbon fiber or the carbon nanofiber is selected from, for example, polyacrylonitrile (PAN), polybenzylimidazole (PBI), cellulose (Cellulose), phenol (Phenol), and pitch (Pitch) It may be formed from one or more precursors, but is not limited thereto.

The length of the first conductive continuous fiber bundle 110 may be about 0.1mm to about 2.0mm. When the fuel cell separator is formed by the fuel cell separator composite material 100 by having a length within the range, the longitudinal direction L of the first conductive continuous fiber bundle 110 is an upper portion of the fuel cell separator. It can be formed to be perpendicular to the surface and the lower surface, and accordingly the current can flow along the first conductive continuous fiber bundle 110, the flow of the current is uniform, preventing the breakage to provide excellent electrical conductivity and low contact resistance Can be implemented.

When the length of the first conductive continuous fiber bundle 110 is less than about 0.1 mm, the orientation of the fiber in the process of impregnating the first conductive continuous fiber bundle 110 in one direction with the impregnation resin 120 is performed. The first conductive continuous fiber bundle 110 when the fuel cell separator is formed due to the limitation according to the thickness standard of the fuel cell separator when it is easily distracted and difficult to maintain the aligned state in one direction and is greater than about 2.0 mm The longitudinal direction (L) of can not be formed to be perpendicular to the upper surface and the lower surface of the fuel cell separation plate, and can only be formed in parallel.

However, when the layers formed of the first conductive continuous fiber bundles 110 aligned in one direction are parallel to the upper and lower surfaces of the fuel cell separation plate, the impregnation has insulation performance between the plurality of layers. The layered portion formed only of the resin 120 may be included so that the flow of current may be partially interrupted, and thus the contact resistance and electrical conductivity may be further reduced.

For example, the first conductive continuous fiber bundle 110 may have a thickness of about 0.1 mm to about 0.2 mm, and a width of about 1.0 mm to about 20.0 mm. By having a thickness and a width within the above range can be more easily aligned in the one direction while the fuel cell separator prepared therein can implement excellent flexural strength.

As the filament, an average diameter of the first conductive continuous fiber may be about 7 μm to about 30 μm. By having the diameter within the above range can be easily impregnated impregnation resin 120 can be implemented to excellent level of flexural strength of the fuel cell separator.

As the filament, the linear density of the first conductive continuous fiber may be about 800 g / km to about 4,000 g / km. By having a linear density within the above range, it is possible to appropriately include a layer formed by the first conductive continuous fiber bundle 110 aligned in one direction, thereby improving productivity and forming a total weight at an appropriate level, thereby realizing weight reduction. have.

Specifically, if less than about 800g / km should include too much of the layer may increase the manufacturing time and productivity may be reduced, if it is more than about 4,000g / km it is difficult to form a fuel cell separator plate in a thin thickness and total There is a problem that the weight is difficult to realize the weight increase.

The impregnation resin 120 may be a thermoplastic resin, and the thermoplastic resin may be, for example, polyethylene, polypropylene, polyurethane, polyethylene terephthalate, polybutylene terephthalate, or the like. (polybutyleneterephthalate), polyurea, polyvinylchloride, polyvinylacetate, ethylenevinylacetate, melamine, phenol, polyphenylene sulfide, It may include at least one selected from the group consisting of polyamide, polyimide, polybenzimidazole, polyetheretherketone, acryl, and combinations thereof.

In addition, the impregnation resin 120 may specifically include polyamide, thereby further improving flexural strength.

The weight ratio of the impregnating resin 120 to the first conductive continuous fiber bundle 110 may be, for example, about 1:40 to about 1:99, and specifically about 1:70 to about 1:90. . By having a weight ratio within the above range, the composite material 100 for the fuel cell separator can realize both excellent durability and excellent electrical conductivity at the same time.

The fuel cell separator 100 may include, for example, about 1 to about 100 layers formed of the first conductive continuous fiber bundle 110 aligned in one direction. The fuel in the direction perpendicular to the layer by including the number of the range within the range while properly adjusting the gap between the layers to a level necessary to implement the durability and electrical conductivity of the fuel cell separator composite 100 to the required level. The thickness of the composite material for battery separator 100 can be adjusted appropriately.

The thickness d _v of the composite material for a fuel cell separator 100 in a direction perpendicular to the layer may be about 0.12 mm to about 22.0 mm. The thickness d _v of the composite material for a fuel cell separator 100 in a direction perpendicular to the layer may be a width of a surface at which an end surface of the first conductive continuous fiber bundle 110 is exposed.

When the fuel cell separator is formed of the composite material for the fuel cell separator 100 by having a thickness within the range, the length direction of the first conductive continuous fiber bundle 110 is greater than the thickness of the fuel cell separator. It may be formed so as to be perpendicular to the upper surface and the lower surface of the fuel cell separation plate, so that the current flow direction of the fuel cell separation plate and the longitudinal direction (L) of the first conductive continuous fiber bundle 110 is the same. As a result, the current flow can be uniformly prevented and the breakage can be effectively prevented, thereby achieving low contact resistance and excellent electrical conductivity.

The width d _p of the fuel cell separator composite material 100 in a direction parallel to the layer and perpendicular to the longitudinal direction of the first conductive continuous fiber bundle 110 is about 25.0 mm to about 100.0 mm. May be, but is not limited thereto. The width d _p of the fuel cell separator composite 100 in a direction perpendicular to the longitudinal direction of the first conductive continuous fiber bundle 110 while being parallel to the layer is the first conductive continuous fiber bundle ( The distal face of 110 may be the width of the exposed face.

In one embodiment, the first conductive continuous fiber bundle 110 is uniformly aligned in one direction, the plurality of layers may all be parallel, and thus the longitudinal direction of the first conductive continuous fiber bundle 110 (L) may all be parallel, and accordingly, when the fuel cell separator is formed to form the fuel cell separator, the current flow direction and the longitudinal direction L are the same so that the current flows. Can be made uniform and the disconnection can be prevented.

In the case of using short fibers or the like, for example, needle punching or an electrostatic wool process may be applied to orient the fibers in a predetermined direction. This disturbance makes it difficult to maintain the alignment in one direction, so that the current in the fuel cell separator flows unevenly and may be partially disconnected. The length of such short fibers can be from about 2.0 mm to about 5.0 mm, for example.

The composite material for fuel cell separator 100 can be more uniformly aligned in one direction more easily by using straight continuous fibers, it is possible to maintain an excellent level of the orientation of the fiber even by the subsequent resin impregnation process, As described above, in the case of forming the fuel cell separator, it is possible to uniformize the flow of current and to prevent disconnection.

When the at least one composite material for fuel cell separator 100 is formed as a fuel cell separator, both end faces of the first conductive continuous fiber bundle 110 have upper and lower surfaces of the fuel cell separator. Each can be exposed to a cotton. Accordingly, current can flow easily through both end surfaces, so that the contact resistance of the fuel cell separation plate can be further lowered, thereby achieving better electrical conductivity.

Referring to FIG. 1, the composite material for a fuel cell separator 100 includes two surfaces each of which both end surfaces of the first conductive continuous fiber bundle 110 are exposed and a side surface S ₂ therebetween. When the plurality of fuel cell separator composites 100 is formed as a fuel cell separator, the fuel cell separator may be attached to the side surface S ₂ .

That is, after the lamination in one of one side surface (S ₂₎ of the fuel cell separating panyong composite material 100, one side surface (S ₂₎ and the other one of the fuel cell separating panyong composite material 100 of the contact with each other by way of hot pressing It can be formed by attaching and molding.

Accordingly, when the plurality of fuel cell separator composites 100 are formed as fuel cell separators, a pair of exposed ends of the first conductive continuous fiber bundle 110 of the plurality of fuel cell separators composite 100 is exposed. Surfaces (S ₁ ) of the to form a pair of planes, the pair of planes may be formed as the upper surface and the lower surface of the fuel cell separator, respectively, the upper surface and the lower surface of the fuel cell separator An end surface of the first conductive continuous fiber bundle 110 may be exposed on a surface.

In one embodiment, the longitudinal direction of the first conductive continuous fiber bundle 110 may be perpendicular to the upper surface and the lower surface of the fuel cell separator.

Accordingly, the flow direction of the current in the fuel cell separator and the longitudinal direction L of the first conductive continuous fiber bundle 110 are the same so that the current flows from the upper surface to the lower surface or in the opposite direction. Since it can easily flow along the first conductive continuous fiber bundle 110, as described above, by aligning the first conductive continuous fiber bundle 110 in one direction to uniformly flow the current and at the same time to prevent disconnection The fuel cell separator may realize lower contact resistance and better electrical conductivity.

In one embodiment, the composite material for fuel cell separator 100 may not include a conductive filler separately.

In order to satisfy the electrical and thermal conductivity required in the fuel cell separator, a step of adding a large amount of conductive fillers, etc., in addition to the conductive fibers must be added. Therefore, the process becomes complicated and the time and cost are further consumed, resulting in low productivity. In the case of containing such a conductive filler in a large amount, there is a problem in that moldability and workability are reduced.

As described above, the composite material 100 for the fuel cell separator plate is exposed to the end surface of the first conductive continuous fiber bundle 110 on the upper and lower surfaces of the fuel cell separator plate, the first conductive continuous fiber bundle 110. Since the longitudinal direction (L) of the) can be formed to be the same as the current flow direction there is an advantage that can implement a low contact resistance and excellent electrical conductivity without including a separate conductive filler.

Accordingly, the manufacturing process of the fuel cell separator 100 may be simplified, thereby reducing time and cost, thereby effectively improving productivity, and at the same time, forming processability of the fuel cell separator 100 may be further improved. Can be.

The conductive filler is, for example, carbon powder, platelet graphite, spheroidal graphite, expanded graphite, carbon black, acetylene black, Ketjen black, denka black, super P, activated carbon, carbon fiber, carbon nanotube, carbon nanofiber, carbon It may mean a nano wire, carbon nano horn, carbon nano ring, etc., but is not limited thereto.

In one embodiment, the layer included in the fuel cell separator composite 100 may further include or may not include a second conductive continuous fiber bundle aligned in a direction different from the one direction. The second conductive continuous fiber bundle may be the same as described above with respect to the first conductive continuous fiber bundle 110 except that the second conductive continuous fiber bundle is aligned in the different directions.

The second conductive continuous fiber bundle may be included in the form of a woven fabric interwoven with each other with respect to the first conductive continuous fiber bundle 110, or partially or on the first conductive continuous fiber bundle 110 without being woven. It may be included in a close contact as a whole, but is not limited thereto.

When the second conductive continuous fiber bundle is further included, the flexural strength tends to be lowered, but the external impact may be more easily absorbed, for example, the impact strength may be improved, and thus further appropriately included according to the purpose and use of the invention. It may or may not include it.

When the second conductive continuous fiber bundle is included in the form of a woven fabric, for example, the first conductive continuous fiber bundle 110 aligned in one direction is inclined, and the second conductive continuous fiber bundle is a weft yarn. It can be woven by sandwiching between the first conductive continuous fiber bundle 110, but is not limited thereto.

The weave form may mean a woven fabric in a form including at least one selected from the group consisting of plain weave, twill weave, satin weave, and combinations thereof, and the specific weave form may be selected according to physical properties or uses to be implemented. .

For example, when the second conductive continuous fiber bundle is included, the weight ratio of the impregnated resin 120 to the second conductive continuous fiber may be about 1:40 to about 1:99, and specifically about 1:70. To about 1:90. By being included in the content within the above range it is possible to appropriately control the electrical conductivity and durability to implement these two physical properties at an excellent level at the same time.

In another embodiment of the present invention, the fuel cell separator is formed by the composite material 100 for the separator, both end faces (end face) of the first conductive continuous fiber bundle 110 is exposed on the upper and lower surfaces, respectively. A fuel cell separator 200 is provided. 2 schematically shows a perspective view of the fuel cell separator 200. The fuel cell separator composite material 100 is as described above in one embodiment.

The fuel cell separator 200 is exposed in the longitudinal direction of the first conductive continuous fiber bundle 110 while the end surface of the first conductive continuous fiber bundle 110 aligned in one direction is exposed on the upper surface and the lower surface ( L) is formed in the same direction as the current flow direction in the fuel cell separator 200, so that the current can flow along the first conductive continuous fiber bundle 110, thereby making the flow of current uniform and The breakage of the flow can be effectively prevented.

The composite material for fuel cell separator 100 includes two surfaces each of which both end surfaces of the first conductive continuous fiber bundle 110 are exposed and a side surface S ₂ therebetween, and includes a plurality of fuel cell separator plates. Composite 100 may be attached to the side (S ₂ ) by thermocompression molding.

That is, after the lamination in one of one side surface (S ₂₎ of the fuel cell separating panyong composite material 100, one side surface (S ₂₎ and the other one of the fuel cell separating panyong composite material 100 of the contact with each other by way of hot pressing It can be formed by attaching and molding. Accordingly, when the plurality of fuel cell separator composites 100 are formed of the fuel cell separator 200, the ends of the first conductive continuous fiber bundles 110 of the plurality of fuel cell separator composites 100 are exposed. The pair of surfaces (S ₁ ) can be gathered to form a pair of planes, the pair of planes may be formed as the upper surface and the lower surface of the fuel cell separation plate 200, respectively, the fuel cell separation End surfaces of the first conductive continuous fiber bundles 110 may be exposed on the top and bottom surfaces of the plate 200.

In another embodiment, the longitudinal direction (L) of the first conductive continuous fiber bundle 110 may be perpendicular to the upper surface and the lower surface of the fuel cell separator 200, and thus the first conductive continuous The longitudinal direction L of the fiber bundle 110 may be the same as the flow direction of the current in the fuel cell separator 200, thereby realizing excellent electrical conductivity and low contact resistance.

The total thickness of the separator may be about 0.1 mm to about 2.0 mm. By having a thickness within the above range, it is possible to sufficiently realize the separation performance for maintaining the insulation without excessively increasing the size of the fuel cell or unit cell including the separator. When the total thickness of the separator exceeds about 2.0 mm, there is a problem in that the weight and size of the separator, which occupies the largest weight ratio among the components of the fuel cell, cannot be achieved.

The fuel cell separator 200 may have, for example, a contact resistance of about 20 mΩ · cm ² or less, specifically, about 10 mΩ · cm ² to about 20 mΩ · cm ² , and a corrosion current density, for example. , may be up to about 10μA / cm ^2, specifically, approximately 1.5μA / cm ² to about may be 10μA / cm ^2. By having a contact resistance within the above range can implement excellent electrical conductivity to further improve the energy efficiency of the fuel cell, and at the same time having a corrosion current density within the above range can be improved corrosion resistance can be realized long-term excellent durability.

In addition, the electrical conductivity of the fuel cell separator 200 may be about 100S / cm to about 200S / cm, and thus may implement excellent electrical properties, thereby improving energy efficiency.

In addition, the fuel cell separator 200 may have a flexural strength of about 94 MPa to about 400 MPa. By having the flexural strength within the above range it can sufficiently withstand the external impact can implement excellent durability. Specifically, the flexural strength may be measured according to the conditions of ASTM D 790.

In another embodiment of the present invention, there is provided a method of manufacturing the fuel cell separator, and FIG. 3 schematically shows a process flow diagram of the method. 4 to 7 schematically show schematic diagrams illustrating each of the following steps included in the manufacturing method.

The manufacturing method includes forming a first conductive continuous fiber bundle sheet (S1); After stacking the plurality of first conductive continuous fiber bundle sheets, immersion and drying are performed on the impregnated resin, or the first conductive continuous fiber bundle sheets and the impregnated resin films are alternately laminated, and then thermocompression bonding is performed. Forming a preliminary composite (S2); Cutting the preliminary composite material perpendicularly to the longitudinal direction of the first conductive continuous fiber bundle at regular intervals within a range of about 0.1 mm to about 2.0 mm to form a composite for a fuel cell separator (S3); And manufacturing a fuel cell separation plate such that both end faces of the first conductive continuous fiber bundle are exposed on the upper and lower surfaces of the fuel cell separation plate as the at least one composite material for the fuel cell separation plate. S4);

By the above production method, the composite material for a fuel cell separator described above in one embodiment and the fuel cell separator described above in another embodiment can be manufactured, whereby the fuel cell separator has excellent processability, excellent productivity, excellent molding processability, Excellent corrosion resistance, low contact resistance and good electrical conductivity can be achieved.

The first conductive continuous fiber bundle, the impregnation resin and the composite material for the fuel cell separator are as described above in one embodiment.

In addition, the first conductive continuous fiber bundle sheet may have a thickness of, for example, about 200 μm to about 300 μm, and the impregnated resin film is a film formed of the impregnated resin, for example, about 20 μm to It may be about 100㎛, but may vary depending on the purpose and function of the invention, it is not limited thereto.

In the manufacturing method, the first conductive continuous fiber bundle can be aligned in one direction on a single plane to form a first conductive continuous fiber bundle sheet, specifically, the first conductive continuous fiber bundle is uniform in one direction Can be aligned and formed as a sheet. Accordingly, the first conductive continuous fiber bundle sheet may include a first conductive continuous fiber bundle aligned in one direction.

In the forming of the first conductive continuous fiber bundle sheet, the first conductive continuous fiber bundle sheet further includes or does not further include a second conductive continuous fiber bundle aligned in a direction different from the one direction. It can form in a state. The second conductive continuous fiber bundle may be included in the form of a woven fabric interwoven with each other with respect to the first conductive continuous fiber bundle, or in a state of being partially or wholly in contact with the first conductive continuous fiber bundle without being woven. It may be included, but is not limited thereto. The second conductive continuous fiber bundle is as described above in one embodiment.

In the above production method, the plurality of first conductive continuous fiber bundle sheets are laminated, followed by immersion and drying of the impregnated resin, or the first conductive continuous fiber bundle sheets and the impregnated resin film are alternately laminated, and then heated. Compression may be performed to form the preliminary composite. When the first conductive continuous fiber bundle sheet and the impregnated resin film are laminated alternately, the impregnated resin film is impregnated into the first conductive continuous fiber bundle sheet by thermocompression, so any one of them may be formed as the outermost layer. There is no particular limitation.

As shown in FIG. 5, the preliminary composite material may be a composite material formed in a form in which the plurality of first conductive continuous fiber bundle sheets are included in parallel with each other in the impregnation resin, and used to form the composite material for the fuel cell separator. It is a preliminary material. Specifically, the plurality of layers may be included in parallel with each other in the impregnating resin using the first conductive continuous fiber bundle sheet as one layer.

The preliminary composite material may be formed by, for example, performing hot pressing at a temperature of about 100 ° C. to about 300 ° C. by a hot press at a pressure of about 10 kg / cm 2 to about 100 kg / cm 2, but is not limited thereto.

When the first conductive continuous fiber bundle sheet and the impregnated resin film are alternately laminated, the impregnated resin may be applied by applying heat and pressure after laminating the impregnated resin film on the upper, lower, or upper and lower portions of the first conductive continuous fiber bundle sheet. The molten resin can be impregnated with the first conductive continuous fiber bundle to be impregnated.

Accordingly, in the preliminary composite material, the first conductive continuous fiber bundle sheet is formed as one layer, and the plurality of layers may be parallel to each other while the plurality of layers are included, so that the length of the first conductive continuous fiber bundle is provided. The directions can all be parallel.

In the above method, the preliminary composite material may be cut perpendicularly to the longitudinal direction of the first conductive continuous fiber bundle at regular intervals within a range of about 0.1 mm to about 2.0 mm to form a composite material for a fuel cell separator. That is, it is possible to use a composite material for a fuel cell separator formed by cutting perpendicularly to the longitudinal direction of the first conductive continuous fiber bundle at the same interval within the range of about 0.1mm to about 2.0mm, to produce a fuel cell separator In this case, a pair of surfaces of which both end faces of the first conductive continuous fiber bundle are exposed may be gathered to form opposite surfaces, that is, an upper surface and a lower surface of the fuel cell separator.

As such, by cutting at regular intervals within the range, the length of the first conductive continuous fiber bundle included in the fuel cell separator composite may be formed at a level of about 0.1 mm to about 2.0 mm. When the fuel cell separator is formed by the fuel cell separator using a composite material having a length within the range, the longitudinal direction of the first conductive continuous fiber bundle may be formed to be perpendicular to the upper and lower surfaces of the fuel cell separator. As a result, the current may flow along the first conductive continuous fiber bundle, thereby making the flow of the current uniform and preventing breakage, thereby realizing excellent electrical conductivity and low contact resistance.

The fuel cell separator may be manufactured to expose both end faces of the first conductive continuous fiber bundle on the upper and lower surfaces of the fuel cell separator using the at least one composite for fuel cell separator.

For example, when the specification of the cut-off fuel cell separator composite material conforms to the specification of the fuel cell separator to be implemented, the one fuel cell separator composite material is used as the fuel cell separator plate or thermally compressed. It is possible to produce a fuel cell separator by molding. When the composite material for one fuel cell separator is molded by thermocompression bonding, for example, it may be performed by hot pressing, and the temperature and pressure conditions at this time may be appropriately set, and are not particularly limited.

Further, for example, when the size of the cut-off composite material for fuel cell separator is smaller than the size of the fuel cell separator to be implemented, for example, when the thickness in the direction perpendicular to the layer is small, a plurality of The fuel cell separator can be manufactured by attaching and molding two composite materials for a fuel cell separator by thermocompression bonding.

As described above in one embodiment, referring to FIG. 1, the composite material for a fuel cell separator includes two surfaces each of which both end surfaces of the first conductive continuous fiber bundle are exposed and side surfaces therebetween. When the composite material for two fuel cell separators is formed as a fuel cell separator, it may be attached to the side surface.

That is, one side of the composite material for one fuel cell separator and one side of the composite material for another fuel cell separator may be formed by being stacked in contact with each other and then attached and molded by thermocompression bonding.

Accordingly, when a plurality of fuel cell separator composites are formed of a fuel cell separator, a pair of surfaces of which the ends of the first conductive continuous fiber bundles of the plurality of fuel cell separator composites are exposed are gathered to form a pair of planes. The pair of planes may be formed as an upper surface and a lower surface of the fuel cell separation plate, respectively.

The thermocompression may be performed in all directions according to methods known in the art, and may be molded to appropriately apply heat and pressure within a range in which physical properties of the plurality of fuel cell separators are not significantly deformed. Is not particularly limited.

The fuel cell separator may be formed by, for example, performing thermocompression bonding at a pressure of about 1 kg / cm 2 to about 10 kg / cm 2 by a hot press at a temperature of about 100 ° C. to about 300 ° C., but is not limited thereto.

Specifically, the thermocompression forming the composite material for the fuel cell separator is the same or higher temperature than the thermocompression forming the fuel cell separator; Or the same or higher pressure; Can be performed under conditions.

The following presents specific embodiments of the present invention. However, the embodiments described below are merely for illustrating or explaining the present invention in detail, and the present invention is not limited thereto.

실시예Example

Example 1

The first conductive carbon continuous fiber bundle having a length of 1,500 g / km and having a mean density of 7 µm and a first conductive carbon continuous fiber bundle having a length of 250 mm formed of 3,000 strands is aligned on a single plane in one direction. A bundle sheet was prepared, and the size of the first conductive carbon continuous fiber bundle sheet was 250 × 250 × 0.3 mm.

Thereafter, the first conductive carbon continuous fiber bundle sheets aligned in one direction of 20 sheets and 20 sheets of a polypropylene resin film having a size of 250Ⅹ250Ⅹ0.1mm are alternately stacked, and then thermally crimped at a temperature of 220 ° C. and a pressure of 40 kg / cm 2. A composite material for a fuel cell separator was formed.

Subsequently, the composite material for fuel cell separator is cut perpendicular to the longitudinal direction of the first conductive carbon continuous fiber bundle at 2.0 mm intervals, so that the cut fuel composite plate composite material is both ends of the first conductive carbon continuous fiber bundle. The cross-sections each included two exposed faces and sides between them.

Specifically, the length of the first conductive carbon continuous fiber bundle included in the cut fuel cell separator composite was 2.0 mm, and the weight ratio of the polypropylene resin to the first conductive continuous fiber bundle was 1:80.

In addition, five laminated fuel cell separator composite materials were laminated in such a manner that each side was in contact with each other, and then thermocompression-bonded at a temperature of 160 ° C. and a pressure of 5 kg / cm 2 by a hot press (Carver, Auto 30ton). Was attached to prepare a fuel cell separator.

Accordingly, both end surfaces of the first conductive carbon continuous fiber bundle are exposed to the top and bottom surfaces of the fuel cell separator, and the length direction of the first conductive carbon continuous fiber bundle is the top surface of the fuel cell separator. And the direction perpendicular to the lower surface was the same as the current flow direction, and the total thickness of the fuel cell separator was 2.0 mm.

Example 2 (Contains a second conductive continuous fiber bundle)

A second conductive carbon continuous fiber bundle having a length of 250 mm formed of 3,000 second conductive carbon continuous fibers having an average diameter of 7 μm and a linear density of 1650 g / km is interwoven with the first conductive carbon continuous fiber bundles to cross each other. A fuel cell separator was manufactured in the same conditions and methods as in Example 1 except that the first conductive carbon continuous fiber bundle sheet further includes a second conductive carbon continuous fiber bundle arranged in a direction different from the one direction.

Specifically, the length of the second conductive carbon continuous fiber bundle included in the cut fuel cell separator composite was 250 mm, the weight ratio of the polypropylene resin to the second conductive carbon continuous fiber bundle was 1:80, and the fuel cell separator was The total thickness of was 2.0 mm.

Comparative Example 1 (Including Polymer Resin and Conductive Filler and Containing Less Conductive Filler)

A fuel cell separator was manufactured by injection molding a composition obtained by mixing and stirring 50% by weight of polypropylene resin and 50% by weight of carbon black as the conductive filler.

The total thickness of the fuel cell separator was 2.0 mm.

Comparative Example 2 (Including Polymer Resin and Conductive Filler, Containing Conductive Filler in Appropriate Amount)

20% by weight polypropylene resin; And a fuel cell separator in the same manner as in Comparative Example 1 except for mixing and stirring carbon black and carbon nanotubes as a conductive filler so that the total thereof was 80% by weight.

The total thickness of the fuel cell separator was 2.0 mm.

Comparative Example 3 (Including Short Fiber)

Short carbon fibers having an average diameter of 7 µm and a length of 2 mm form a sheet of short carbon fibers oriented generally in one direction using an electrostatic cap technique, and then infiltrate the liquid polypropylene resin into the short carbon fiber sheet to provide fuel. A composite material for a battery separator was prepared and the weight ratio of polypropylene resin to short carbon fiber was 1:50.

Further, the composite material was then formed by hot pressing at a temperature of 160 ° C. and a pressure of 5 kg / cm 2 by hot press (Carver, Auto 30ton) to manufacture a fuel cell separator, and the total thickness of the fuel cell separator was Was 2.0 mm.

Comparative Example 4 (When the Longitudinal Direction of Carbon Fiber is Parallel to the Upper and Lower Surfaces of the Fuel Cell Separator)

A bundle of 250 mm long conductive carbon continuous fibers formed of 3,000 first conductive continuous fibers having an average diameter of 7 μm and a linear density of 1650 g / km is woven to cross each other with warp and weft to form a woven carbon continuous fiber sheet. The carbon continuous fiber sheet was 250 × 250 × 0.025mm in size, and the spacing between the warp yarns and the weft yarns were the same.

Subsequently, three carbon continuous fiber sheets and two 250 Ⅹ 250 Ⅹ 0.025 mm polypropylene resin films were alternately laminated, and thermally crimped at a pressure of 40 kg / cm 2 and a temperature of 220 ° C. to manufacture a fuel cell separator. The total thickness of the fuel cell separator was 2.0 mm.

Considering the general specification of the fuel cell separator, the direction in which the carbon continuous fibers are aligned should be mounted so that the longitudinal direction of the carbon continuous fibers is parallel to both the top and bottom surfaces of the fuel cell separator. It was different from the flow direction of the current. In addition, there was a layer portion comprising only polypropylene resin between the sheets of carbon fiber. 4 is a schematic perspective view of a fuel cell separator according to Comparative Example 4.

실험예Experimental Example

The physical properties of the fuel cell separator according to Examples 1 and 2 and Comparative Examples 1-4 were evaluated, and are shown in Table 1 below.

평가 방법Assessment Methods

Flexural strength

Measuring method: measured using a flexural strength meter (Instron, 5569A) according to ASTM D 790.

(Electric conductivity and contact resistance)

Measurement method: Measurement was performed using a 4-probe method by Keithley (Keithley / 6220 / 2182A, USA).

In addition, in the contact resistance measuring instrument, a compression holding tester (Instron Co., Ltd., 5569A 5566) using a pressure of 100N / cm ² to provide a measurement.

(Molding processability).

Measuring method: By visually observing whether grooves or cracks were formed on the surface of the fuel cell separator according to Examples 1 and 2 and Comparative Examples 1-4, the grooves and cracks did not occur, and thus the moldability was excellent. The case was indicated by "○", the case where the grooves or cracks occurred and the moldability was inferior was indicated by "Ⅹ", and the good case was indicated by "Δ".

(The grooves and cracks were observed to be those having a depth of 1mm or more.)

	굴곡강도(MPa)Flexural Strength (MPa)	전기전도도(S/cm)Electrical Conductivity (S / cm)	접촉저항(mΩ·cm²)Contact resistance (mΩcm ² )	성형 가공성Moldability
실시예1Example 1	200200	100100	1515	○○
실시예2Example 2	150150	100100	2020	○○
비교예1Comparative Example 1	3030	0.010.01	10001000	○○
비교예2Comparative Example 2	3030	0.020.02	200200	ⅩⅩ
비교예3Comparative Example 3	6060	22	100100	△△
비교예4Comparative Example 4	150150	9090	4040	○○

The fuel cell separators according to Examples 1 and 2 were found to have excellent bending performance, electrical conductivity, contact resistance, and excellent molding processability.

On the other hand, the fuel cell separator according to Comparative Examples 1 to 4 was found to have a significantly lower electrical conductivity and a significantly higher contact resistance, resulting in inferior performance. In particular, in Comparative Examples 1 to 3, the flexural strength was inferior, and in Comparative Example 2, it was clearly confirmed that the molding processability was also inferior.

100: composite material for fuel cell separator

110: first conductive continuous fiber bundle aligned in one direction

120: impregnation resin

S ₁ : A pair of surfaces in which the end faces of the first conductive continuous fiber bundles are exposed

S ₂ : side surface between a pair of surfaces of which the end surface of the first conductive continuous fiber bundle is exposed

L: longitudinal direction of the first conductive continuous fiber bundle

200: fuel cell separator

d _v : thickness of the composite for fuel cell separator in the direction perpendicular to the layer

d _p : Width of the composite material for a fuel cell separator in a direction parallel to the layer and perpendicular to the longitudinal direction of the first conductive continuous fiber bundle.

Claims

A first conductive continuous fiber bundle and an impregnation resin aligned in one direction,

The first conductive continuous fiber bundle arranged in one direction as a single layer comprising a plurality of layers

Composite material for fuel cell separator.
The method of claim 1,

The plurality of layers are parallel to each other

Composite material for fuel cell separator
The method of claim 1,

When the at least one composite for fuel cell separator is formed of a fuel cell separator, both end faces of the first conductive continuous fiber bundle are exposed to the top and bottom surfaces of the fuel cell separator, respectively.

Composite material for fuel cell separator.
The method of claim 3,

The composite material for a fuel cell separator includes two surfaces each of which both end surfaces of the first conductive continuous fiber bundle are exposed and side surfaces therebetween.

When a plurality of composites for fuel cell separator are formed of a fuel cell separator, they are attached to the side surface.

Composite material for fuel cell separator.
The method of claim 1,

When the at least one composite for fuel cell separator is formed of a fuel cell separator, the longitudinal direction of the first conductive continuous fiber bundle is perpendicular to the top and bottom surfaces of the fuel cell separator.

Composite material for fuel cell separator.
The method of claim 1,

Does not contain conductive filler separately

Composite material for fuel cell separator.
The method of claim 1,

The length of the first conductive continuous fiber bundle is 0.1mm to 2.0mm

Composite material for fuel cell separator.
The method of claim 1,

The first conductive continuous fiber bundle is formed as a fiber filament, the first conductive continuous fibers, for example, the average of 1,000 to 48,000 strands are concentrated,

The thickness of the first conductive continuous fiber bundle is 0.1mm to 0.2mm, the width is 1.0mm to 20.0mm

Composite material for fuel cell separator.
The method of claim 1,

The linear density of the first conductive continuous fiber is 800g / km to 4,000g / km

Composite material for fuel cell separator.
The method of claim 1,

The weight ratio of the impregnated resin to the first conductive continuous fiber bundle is 1:40 to 1:99

Composite material for fuel cell separator.
The method of claim 1,

1 to 100 of the layers

Composite material for fuel cell separator.
The method of claim 1,

Thickness in the direction perpendicular to the layer is 0.12 mm to 22.0 mm

Composite material for fuel cell separator.
The method of claim 1,

25.0 mm to 100.0 mm in width in the direction perpendicular to the longitudinal direction of the first conductive continuous fiber bundle while being parallel to the layer.

Composite material for fuel cell separator.
The method of claim 1,

The first conductive continuous fiber includes an organic fiber, an inorganic fiber, or both of which the surface of the fiber is coated with a conductive filler or the conductive filler is dispersed in the fiber.

Composite material for fuel cell separator.
The method of claim 1,

The layer further comprises or does not comprise a second bundle of conductive continuous fibers aligned in a direction different from the one direction.

Composite material for fuel cell separator.
16. An end face of each of the first conductive continuous fiber bundles is formed by the composite for at least one fuel cell separator according to any one of claims 1 to 15, and the upper and lower surfaces are respectively exposed. Done

Fuel cell separator.
The method of claim 16,

The composite material for a fuel cell separator includes two surfaces each of which both end surfaces of the first conductive continuous fiber bundle are exposed and side surfaces therebetween.

A plurality of fuel cell separator plate composite material is attached to the side by thermocompression molding

Fuel cell separator.
The method of claim 16,

The longitudinal direction of the first conductive continuous fiber bundle is perpendicular to the upper surface and the lower surface of the fuel cell separation plate

Fuel cell separator.
The method of claim 16,

The total thickness of the fuel cell separator is 0.1mm to 2.0mm

Fuel cell separator.
The method of claim 16,

Contact resistance is 20 mΩ · cm 2 or less,

Electrical conductivity is 100S / cm to 200S / cm

Fuel cell separator.
The method of claim 16,

Flexural strength of 94MPa to 400MPa

Fuel cell separator.
Forming a first conductive continuous fiber bundle sheet;

After stacking the plurality of first conductive continuous fiber bundle sheets, immersion and drying are performed on the impregnated resin, or the first conductive continuous fiber bundle sheets and the impregnated resin films are alternately laminated, and then thermocompression bonding is performed. Forming a preliminary composite;

Cutting the preliminary composite material perpendicularly to the longitudinal direction of the first conductive continuous fiber bundle at regular intervals within a range of 0.1 mm to 2.0 mm to form a composite material for a fuel cell separator; And

Manufacturing a fuel cell separator plate such that both end faces of the first conductive continuous fiber bundle are exposed on the top and bottom surfaces of the fuel cell separator plate using the at least one composite material for the fuel cell separator plate;

Method of manufacturing a fuel cell separator comprising a.