JP2008311108A - Fuel cell separator, its manufacturing method, and fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell separator which can be manufactured easily and at low cost and has a sufficient conductivity and mechanical characteristics, and its manufacturing method, as well as a fuel cell using such a fuel cell separator. <P>SOLUTION: The fuel cell separator has a separator main body 12 consisting of a first forming material with a volume resistivity of 10 mΩ cm or less and a reinforcement part 14 which is installed at the periphery of the separator main body 2 and consists of a second forming material with a bending strength of 50 MPa or more, and the interface of the separator main body 12 consisting of the first forming material and the reinforcement part 14 consisting of the second forming material includes a concavo-convex face 151 or an inclined face 152. Its manufacturing method as well as a fuel cell equipped with such fuel cell separator are provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell separator, a method for producing the same, and a fuel cell using such a fuel cell separator.

  Conventionally, as a fuel cell, a unit cell in which an ion exchange membrane is sandwiched between a pair of electrodes (a fuel electrode and an air electrode), a flow path of fuel (for example, hydrogen gas, methanol, etc.), and air (oxygen gas) In addition, a laminate in which a large number of grooves are formed on both sides to form a water flow path is known.

  The separator in such a fuel cell has a function as a passage for supplying hydrogen gas, methanol, etc., which is a fuel, and discharging water, carbon dioxide gas, etc. to be generated, as well as a collector that electrically connects the unit cells. It also has a function as an electric body. Therefore, the separator is required to have high conductivity, that is, low penetration (volume) resistivity.

  For this reason, conventionally, as a material for the separator, development has been progressed mainly on a metal material and a carbon material. For example, stainless steel or the like is used as the metal material, and as the carbon material, a molded product obtained by press-molding an expanded graphite sheet, a resin impregnated product obtained by impregnating and curing a carbon sintered body with a resin, or a thermosetting resin is fired. Glassy carbon and the like.

  However, due to the problem of corrosion resistance, the metal material has to be coated with a corrosion resistance coating with a noble metal or carbon on the surface, resulting in problems such as high cost and reduced durability. Further, the carbon material requires a high-precision cutting machine and an expensive high-pressure molding machine, and there is a problem in cost as in the case of a metal material.

  In order to solve these problems, it has been proposed to use a molded body obtained by mixing and molding carbon powder and a thermosetting resin as a separator (see, for example, Patent Document 1). However, such a separator material has a problem that the electrical resistance value in the thickness direction is high, and sufficient conductivity cannot be ensured.

Therefore, methods for increasing the conductivity by increasing the blending amount of carbon powder or adding a conductive auxiliary agent have been proposed, but the conductivity is improved to some extent by using these methods. In addition, the mechanical properties are lowered, such as the bending strength is reduced and the amount of strain is reduced, and the separator may be damaged when the fuel cell is assembled.
JP 2000-311695 A

  The present invention has been made in response to the above-described problems of the prior art, and can be manufactured easily and inexpensively, and has sufficient conductivity and mechanical properties required for the separator, and a fuel cell separator therefor It is an object of the present invention to provide a manufacturing method and a fuel cell using such a fuel cell separator.

  The separator for a fuel cell according to one embodiment of the present invention has a separator body made of a first molding material having a volume resistivity of 10 mΩ · cm or less, and a bending strength provided at a peripheral portion of the separator body of 50 MPa or more. And the interface between the separator body made of the first molding material and the reinforcement body made of the second molding material includes an uneven surface or an inclined surface. It is characterized by that.

  Moreover, the method for manufacturing a separator for a fuel cell according to one aspect of the present invention includes a separator body made of a first molding material having a volume resistivity of 10 mΩ · cm or less, and a peripheral portion of the separator body. A reinforcing body portion made of a second molding material having a bending strength of 50 MPa or more, and an interface between the separator body made of the first molding material and the reinforcing body portion made of the second molding material is an uneven surface. Alternatively, a method of manufacturing a fuel cell separator including an inclined surface, wherein a partition member having a shape corresponding to the interface is disposed inside a molding die, and the first and first portions are disposed inside and outside the partition member. Each of the two molding materials is supplied and cured, and the partition member is removed when the first and second molding materials are in a semi-cured state.

  A method for manufacturing a fuel cell separator according to another aspect of the present invention includes a separator body made of a first molding material having a volume resistivity of 10 mΩ · cm or less, and a peripheral portion of the separator body. And a reinforcing body portion made of a second molding material having a bending strength of 50 MPa or more, and an interface between the separator body made of the first molding material and the reinforcing body portion made of the second molding material. A method for producing a separator for a fuel cell including a concavo-convex surface or an inclined surface, the first molded body serving as the separator body pre-molded with the first molding material inside a molding die, Alternatively, a second molded body that is the reinforcing body portion that has been molded in advance with the second molding material is disposed, and the outer side of the first molded body or the inner side of the second molded body, 2nd molding material It is characterized by curing the integrally supplying the first molding material.

  Furthermore, a fuel cell according to an aspect of the present invention includes the fuel cell separator.

  The fuel cell separator according to one embodiment of the present invention can be easily and inexpensively manufactured, and can have excellent conductivity and mechanical properties required for the separator. In addition, according to the method for manufacturing a fuel cell separator according to one aspect of the present invention, a fuel cell separator having such excellent characteristics can be easily manufactured. Furthermore, the fuel cell according to one embodiment of the present invention can include a fuel cell separator having such excellent characteristics.

  Embodiments according to the present invention will be described below. Although the description will be made based on the drawings, the drawings are provided for illustration only, and the present invention is not limited to the drawings. It should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Furthermore, in the description of the following drawings, common portions are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a perspective view showing an embodiment of a fuel cell separator of the present invention.

  As shown in FIG. 1, a fuel cell separator 10 according to this embodiment includes a separator body 12 made of a first molding material as will be described later, and a reinforcement made of a second molding material provided integrally therewith. The body part 14 is comprised. Moreover, the whole is formed in a flat plate shape, and grooves 16a and 16b serving as gas or liquid flow paths are formed in parallel on both main surfaces, and the groove 16a provided on one main surface and the other The grooves 16b provided on the main surface are provided so as to be orthogonal to each other. The thickness of the fuel cell separator 10 is, for example, about 0.5 to 5.0 mm.

  The first molding material for forming the separator body 12 has a volume resistivity of 10 mΩ · cm or less, preferably 1 to 8 mΩ · cm. If the volume resistivity exceeds 10 mΩ · cm, the conductivity required for the fuel cell separator cannot be ensured.

  In addition, the second molding material forming the reinforcing body portion 14 has a bending strength of 50 MPa or more, and preferably 80 to 150 MPa. When the bending strength is less than 50 MPa, the mechanical characteristics are insufficient, and the separator is easily damaged when the fuel cell is assembled.

  Furthermore, in the present embodiment, the interface between the separator body 12 made of the first molding material and the reinforcing body portion 14 made of the second molding material is, for example, as shown in FIGS. It is composed of an uneven surface 151 or an inclined surface 152. The shape and size of the uneven surface 151, the inclination angle of the inclined surface 152, the inclination direction, and the like are not particularly limited. For example, the uneven surface 151 is a flat surface as shown in FIGS. It may be formed or may be formed as a curved surface as shown in FIG. Similarly, the inclined surface 152 may be formed as a flat surface or a curved surface. Furthermore, unevenness may be formed on the inclined surface 152. Moreover, the whole interface does not need to be the same shape, The combination of various shapes may be sufficient. In short, as long as the entire interface is not a surface 153 perpendicular to the upper surface (or lower surface) of the separator 10 as shown in FIG. Therefore, the surface 153 perpendicular to a part of the interface may be included. However, from the viewpoint of ensuring conductivity, ease of formation, uniformity of strength, and the like, the shape as shown in FIG. 2C is preferable, for example.

  The fuel cell separator 10 thus configured is formed of a molding material having an excellent conductivity with a volume resistivity of 10 mΩ · cm or less excluding the peripheral part, and the peripheral part has an excellent bending strength of 50 MPa or more. It is formed of a molding material having mechanical properties. Moreover, those interfaces are mainly composed of uneven surfaces or inclined surfaces. Accordingly, the high conductivity required for the fuel cell separator is ensured, and the separator is not damaged when the fuel cell is assembled. The reinforcing body portion 14 is preferably formed with a substantially uniform width around the separator body 10, and the ratio of the reinforcing body portion 14 to the entire fuel cell separator 10 depends on the molding material used and the fuel cell separator 10. Depending on the shape, size, etc., it is usually in the range of 5 to 40% by volume.

  Next, the first and second molding materials used for forming the fuel cell separator 10 will be described in detail.

  In the present invention, the first molding material includes, for example, a carbon material and a thermosetting resin, and the volume resistivity is in the above-described range, that is, 10 mΩ · cm or less, preferably 1 to 8 mΩ · cm. The prepared one is used.

  Further, as the second molding material, for example, a material containing a thermosetting resin and prepared so that the bending strength is in the above-described range, that is, 50 MPa or more, preferably 80 to 150 MPa is used.

  As said thermosetting resin, a phenol resin, an epoxy resin, a polyester resin, etc. are mentioned. These resins can be used in combination with a curing agent, a curing accelerator, a curing aid, and the like as required. For example, a curing agent and a curing accelerator are used for the epoxy resin. As the thermosetting resin, a phenol resin and an epoxy resin are preferable from the viewpoint of stability in a hot water environment, and the phenol resin is particularly preferable in the first molding material.

  Examples of the phenol resin include novolac type phenol resins, resol type phenol resins, phenol aralkyl resins, and the like.

  Specific examples of commercially available phenolic resins used in the present invention include PSM-4326 (softening temperature 118-122 ° C.), PSM-6856 (manufactured by Gunei Chemical Co., Ltd.) PSF-2803 (softening temperature 110-120 ° C), PSF-2808 (softening temperature 120-130 ° C), TAMANOL 100S (softening temperature 110-130 ° C) manufactured by Arakawa Chemical Co., Ltd. ), Tamanol 200S (softening temperature 125 to 130 ° C.) (all are trade names). Moreover, as a resol type phenol resin, Arakawa Chemical Co., Ltd. Tamanor 520S (softening temperature 115-130 degreeC), Tamanor 521 (softening temperature 100-115 degreeC), Tamanor 526 (softening temperature 115-130 degreeC) Tamanor 586 (softening temperature 118-125 ° C.), Tamanor 572S (softening temperature 120-130 ° C.) (all are trade names), and the like. In addition, Mitsui Chemicals Co., Ltd.'s phenol / p-xylylene glycol dimethyl ether polycondensate Millex XL, Milex XLC, Mitsui Chemicals' modified phenol / formaldehyde polycondensate Millex RN, Mirex RS, The same Millex VR (all of which are trade names) is also used.

  The phenol resin used in the present invention preferably has a softening temperature of 100 ° C. or higher from the viewpoint of stability and the like. Moreover, in order to ensure the long-term reliability of a fuel cell, it is preferable not to contain an ionic impurity. Therefore, it is preferable to use a resol type phenol resin in which the curing reaction is completed by the resin itself, rather than a novolac type phenol resin that requires a curing agent for the curing reaction.

  Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin and the like.

  Next, artificial or natural graphite powder is preferably used as the carbon material. Artificial graphite includes those derived from petroleum-based coke and those derived from coal-based coke, both of which can be used. As natural graphite, any of scale-like graphite, massive graphite, earth-like graphite and the like can be used. Furthermore, expansive graphite is also preferably used.

The graphite powder used in the present invention preferably has an average particle size of 20 μm or less, more preferably 1 to 10 μm. When the average particle size exceeds 20 μm, the dispersibility is lowered, and the conductivity, mechanical properties, etc. of the cured product are not uniform.
Specific examples of commercially available graphite powder used in the present invention include RP999 (average particle size 3 μm), RP99 (average particle size 3 μm), and RP99 (average particle size 3 μm) manufactured by Ito Graphite Industries Co., Ltd. AC97 (average particle size) as the earth-like graphite powder such as RP98 (average particle size 10 μm), RP97 (average particle size 10 μm), RP90 (average particle size 10 μm), SRP98 (average particle size 5 μm / 10 μm), etc. 7 μm), HAC (average particle size 7 μm), LAC (average particle size 7 μm), AN95 (average particle size 3 μm / 5 μm), AN94 (average particle size 5 μm), APK (average particle size 5 μm / 8 μm) ), AUP (average particle size 0.7 μm) (all are trade names) manufactured by Nippon Graphite Co., Ltd., and the like. In addition, as artificial graphite powder, AGB (average particle size 10 μm), AGBL (average particle size 4 μm), etc. manufactured by Ito Graphite Industries Co., Ltd., as pyrolytic graphite powder, PCGS (average particle size 10 μm), PCG (Average particle diameter of 10 μm) (all are trade names). Furthermore, EC1500 (average particle diameter of 8 μm) manufactured by Ito Graphite Industries Co., Ltd. is used as the expandable graphite, and SNP-BY (average particle diameter of 10 μm) (all are trade names) as special graphite.

  The average particle diameter of the carbon powder is a median diameter measured by a laser diffraction / scattering particle distribution measuring apparatus.

  In the present invention, carbon fiber, carbon black powder, fullerene powder such as a cylinder and a sphere can be used as the carbon material, and these are preferably used as a combined component of the graphite powder. In this case, the carbon material other than the graphite powder is preferably used in a range of 10 parts by mass or less with respect to 100 parts by mass of the graphite powder.

  In addition to carbon powder and thermosetting resin, the first molding material includes monomers, plasticizers, curing agents, curing initiators, curing aids, solvents, UV stabilizers, antioxidants, heat, as necessary. Stabilizers, antifoaming agents, leveling agents, coupling agents, mold release agents, lubricants, water repellents, thickeners, low shrinkage agents, flame retardants, hydrophilicity-imparting agents, and the like that do not impair the effects of the present invention Can be added. In addition to the thermosetting resin, the second molding material includes, as necessary, carbon powder, inorganic filler, monomer, plasticizer, curing agent, curing accelerator, curing initiator, and curing as described above. Auxiliary agent, UV stabilizer, antioxidant, heat stabilizer, antifoaming agent, leveling agent, coupling agent, mold release agent, lubricant, water repellent, thickener, low shrinkage agent, flame retardant, imparting hydrophilicity An agent etc. can be added in the range which does not inhibit the effect of this invention. From the viewpoint of improving strength, the second molding material preferably contains an inorganic filler such as silica powder.

  In this invention, it is preferable that content of the carbon material in a 1st molding material is 70-95 mass%, and it is more preferable that it is 80-90 mass%. Moreover, it is preferable that content of the carbon powder in a 2nd molding material is 0-65 mass%, and it is more preferable that it is 0-40 mass%. If the content of the carbon material in the first molding material is less than 70% by mass, the conductivity will be insufficient, and conversely if it exceeds 95% by mass, the mechanical strength will decrease and the moldability will also be poor. Further, if the content of the carbon material in the second molding material exceeds 65% by mass, sufficient mechanical strength cannot be obtained, and the separator may be damaged when the fuel cell is assembled.

  For example, the first and second molding materials are prepared as follows.

(Preparation of first molding material)
First, the thermosetting resin is previously dissolved in a solvent such as acetone, methanol, ethanol, or a mixed solvent thereof. Next, after charging each component such as a carbon material and a curing agent blended as necessary, a curing accelerator into a mixer capable of reducing the pressure of a universal mixer and using a solvent, Add a solution of thermosetting resin prepared in advance and mix well. Alternatively, a dilute solution of a thermosetting resin is placed in a chemical reaction vessel, and after adding each component such as a carbon material and a curing agent blended as necessary into the solution, a curing accelerator, the mixture is stirred, Filter. Alternatively, a carbon material is put into a high-speed stirrer and stirred at a high speed to keep it in a state close to the fluid phase, and a solution of a thermosetting resin is sprayed on the carbon material. Thereafter, the first molding material can be obtained by evaporating and removing the solvent by, for example, reducing the pressure and heating the mixture.

  The curing catalyst, curing aid, release agent, etc. may be dissolved or dispersed in the thermosetting resin solution in advance. The carbon material may be surface-treated with a coupling agent in advance. A coupling agent is mix | blended in order to improve the interface affinity of a carbon material and a thermosetting resin, and it is preferable to use 0.1-0.5 mass part with respect to 100 mass parts of carbon materials.

(Preparation of second molding material)
When the carbon material is included, it is prepared in the same manner as in the case of the first molding material described above. When carbon material is not included or a small amount (for example, about 10% by weight or less) is included, the blended components are sufficiently mixed (dry blended) with a mixer or the like, and then melt-kneaded with a hot roll or a kneader. After cooling and solidifying, it may be pulverized to an appropriate size.

  The fuel cell separator 10 shown in FIG. 1 can be manufactured, for example, as follows using the first and second molding materials thus prepared.

  A first molding material is supplied to the central portion of a separator molding die having a cavity having a predetermined shape, and a second molding material is supplied to the periphery of the first molding material. At that time, a detachable partition member having a shape corresponding to the interface between the separator main body 12 and the reinforcing body portion 14 described above is mounted in advance in the molding die, and the inner side and the outer side of the partition member are respectively attached. First and second molding materials are supplied. Thereafter, the first and second molding materials are cured under required conditions. When the first and second molding materials are in a semi-cured state, the partition member is removed and further curing is continued. Thereafter, the mold is opened and post-curing is performed if necessary. Thus, the fuel cell separator 10 having a structure in which the separator body 12 made of the first molding material and the reinforcing body portion 14 made of the second molding material are integrated via the interface as described above can be obtained.

  As a molding method, for example, a compression molding method, a transfer molding method, an injection molding method, a casting method, an injection compression molding method, or the like can be used, but it is not particularly limited thereto. The multi-stage press (lamination press) is preferably used in the present invention because a large number of molded articles can be obtained with a small output.

  In the case of using an injection molding method or an injection compression molding method, for the purpose of improving moldability, carbon dioxide gas can be injected from the middle of a cylinder of a molding machine and dissolved in a molding material to be molded in a supercritical state. From the viewpoint of improving the surface accuracy of the molded product, it is preferable to use an injection compression method. Injection compression methods include injection and closing with the mold open, injection while closing the mold, and method of applying the mold clamping force after injection to zero the mold clamping force of the closed mold. However, both are applicable. The molding conditions are appropriately determined depending on the type of molding material to be used. For example, in the case of a graphite high-filling resin composite material, the pressure is usually 50 to 100 MPa, the temperature is 160 to 200 ° C., and the time is 5 to 20 minutes. After molding, for example, by performing post-curing at 180 to 220 ° C. for 30 minutes to 5 hours, the separator characteristics can be further improved.

  The molding material is preferably tableted in advance (preliminarily molded in an uncured state) and filled in a separator molding die for molding. By using such a method, control and adhesion of the interface between the first molding material and the second molding material are improved.

  The fuel cell separator 10 shown in FIG. 1 can also be manufactured without using the partition member as described above. For example, the first molding material is molded into a predetermined shape in advance, and after this is placed in the center of the separator molding die, the second molding material is supplied around it and cured integrally. It may be. Alternatively, the second molding material is molded into a predetermined shape in advance, and this is placed on the peripheral edge in the separator molding die, and then the first molding material is supplied to the inside and cured integrally. You may do it. Since these methods do not use a partition member, there is an advantage that the mold structure can be simplified.

  Such a fuel cell separator 10 can be used as a separator for various types of fuel cells. Among them, solid polymer type, direct methanol type, alkaline type, phosphoric acid type and the like are operated during power generation. It is preferably used as a separator for a so-called low-temperature fuel cell having a temperature of 200 ° C. or lower. The fuel cell separator 10 shown in FIG. 1 is provided with grooves 16a and 16b serving as gas or liquid channels on both sides, but may be provided only on one side, and the shape thereof. Is not particularly limited.

  Here, an embodiment of the fuel cell of the present invention using the fuel cell separator 10 will be described.

  FIG. 3 is a perspective view showing a basic structural unit of an embodiment of the fuel cell of the present invention using the fuel cell separator 10. The fuel cell of the present embodiment is a polymer electrolyte fuel cell, and its basic structural unit is a unit cell comprising an ion exchange membrane 20, a fuel electrode 30 and an air electrode 40, as shown in FIG. The structure is sandwiched between separators 10 for use. And although illustration was abbreviate | omitted, the fuel cell is comprised by laminating | stacking a plurality of such basic structural units, and also providing a current collecting plate at both ends of this laminated body.

  In such a fuel cell, the separator 10 for a fuel cell comprising the highly conductive separator main body 12 and the high strength reinforcing member 14 is used as the separator, so that the manufacturing cost is low and the reliability is high. Can have.

  The present invention is not limited to the description of the embodiment described above, and the structure, material, arrangement of each member, and the like can be appropriately changed without departing from the gist of the present invention. Needless to say.

  EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited to these Examples at all. In the following description, “part” means “part by mass” unless otherwise specified. The volume resistivity of the molding material was measured according to JIS K 7194, and the bending strength was measured according to JIS K 7203.

[Preparation of molding material]
(Preparation Example 1)
In a universal mixer, 500 parts of acetone, 100 parts of a resol type phenol resin (trade name Tamanoru 521, manufactured by Arakawa Chemical Co., Ltd.), and 400 parts of scaly graphite having an average particle size of 10 μm (trade name, RP97, manufactured by Ito Graphite Industries, Ltd.) In this order, after thoroughly mixing, acetone was removed by drying under reduced pressure to obtain resin-coated graphite, and the obtained resin-coated graphite was pulverized with a Henschel mixer to obtain a molding material (A). This molding material (A) had a volume resistivity of 8 mΩ · cm and a bending strength of 50 MPa.

(Preparation Example 2)
435 parts of silica powder having an average particle size of 20 μm (trade name Admafine manufactured by Admatechs), 1.5 parts of γ-glycidoxypropyltrimethoxysilane (trade name A-187 manufactured by Nihon Unicar Co., Ltd.) as a silane coupling agent, 37.5 parts of epoxy resin (trade name NC-3000P manufactured by Sumitomo Chemical Co., Ltd.), 24 parts of phenol resin (trade name GLP-A manufactured by Mitsubishi Gas Chemical Company, Inc.), 1 part of triphenylphosphine as a curing accelerator and carnauba as a mold release agent One part of the wax was mixed at room temperature, kneaded with a heating roll at 60 to 130 ° C., then cooled and pulverized to obtain a molding material (B). This molding material (B) had a volume resistivity of 1 × 10 ¹⁸ mΩ · cm and a bending strength of 200 MPa.

[Manufacture of fuel cell separators]
Example 1
The molding material (A) tableted in the center of the separator mold for fuel cell is filled with the molding material (B) tableted in the peripheral part partitioned by the partition member, respectively (weight ratio (A) / (B) = 1) After molding at a pressure of 100 MPa and a temperature of 180 ° C. for 10 minutes, a post-curing treatment was performed at 200 ° C. for 2 hours to produce a fuel cell separator. In addition, the partition member used the whole interface formed in a shape as shown to Fig.2 (a). Moreover, the partition member was comprised so that it could be removed, keeping the sealing state of a metal mold | die, and it removed from the metal mold 1 minute after the heating start.

(Example 2)
A fuel cell separator was manufactured in the same manner as in Example 1 except that a partition member having the entire interface formed in the shape shown in FIG. 2B was used.

(Example 3)
A fuel cell separator was manufactured in the same manner as in Example 1 except that a partition member having the entire interface formed in the shape shown in FIG. 2C was used.

Example 4
A fuel cell separator was manufactured in the same manner as in Example 1 except that a partition member having the entire interface formed in the shape shown in FIG. 2D was used.

(Example 5)
A fuel cell separator was manufactured in the same manner as in Example 1 except that a partition member having the entire interface formed in the shape shown in FIG. 2E was used.

(Example 6)
A fuel cell separator was manufactured in the same manner as in Example 1 except that a partition member having the entire interface formed in the shape shown in FIG. 2F was used.

(Comparative example)
A fuel cell separator was manufactured in the same manner as in Example 1 except that a partition member having the entire interface formed in the shape shown in FIG. 2G was used.

Various characteristics of the fuel cell separators obtained in the above Examples and Comparative Examples were measured and evaluated by the methods described below.
[Formability]
Generation | occurrence | production of the crack at the time of the separator formation for fuel cells was observed visually, and the following reference | standard evaluated.
○: No cracking △: Partial cracking occurred ×: Cracking occurred and molding was impossible [interfacial strength]
A test piece for a bending test having an interface similar to the interface between the central portion and the peripheral portion of the fuel cell separator was prepared by a method according to JIS K 6019, and the strength of the interface portion was measured according to JIS K 6019. .

  These evaluation results are shown in Table 1.

  As is clear from Table 1, it was confirmed that excellent interfacial strength was obtained in the examples.

It is a perspective view which shows an example of the separator for fuel cells of this invention. It is a figure explaining the shape of the interface of the separator main body of a fuel cell separator, and a reinforcement part. It is a perspective view which shows the basic structural unit of the polymer electrolyte fuel cell of an example of the fuel cell of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Fuel cell separator, 12 ... Separator main body, 14 ... Reinforcing body part, 20 ... Ion exchange membrane, 30 ... Fuel electrode, 40 ... Air electrode, 151 ... Irregular surface, 152 ... Inclined surface

Claims (9)

  A separator body made of a first molding material having a volume resistivity of 10 mΩ · cm or less, and a reinforcing body portion made of a second molding material having a bending strength of 50 MPa or more provided at the peripheral edge of the separator body; And a separator for a fuel cell, wherein an interface between the separator body made of the first molding material and the reinforcing body portion made of the second molding material includes an uneven surface or an inclined surface.   2. The fuel cell separator according to claim 1, wherein the first and second molding materials contain a thermosetting resin.   The fuel cell separator according to claim 2, wherein the thermosetting resin contains an epoxy resin and / or a phenol resin.   The first molding material contains 70 to 95% by mass of a carbon material, and the second molding material contains 0 to 65% by mass of a carbon material. The fuel cell separator as described.   The fuel cell separator according to claim 4, wherein the carbon material is graphite powder.   The fuel cell separator according to any one of claims 1 to 5, wherein the second molding material contains silica powder. A separator body made of a first molding material having a volume resistivity of 10 mΩ · cm or less, and a reinforcing body portion made of a second molding material having a bending strength of 50 MPa or more provided at the peripheral edge of the separator body; A separator for a fuel cell in which an interface between a separator body made of the first molding material and a reinforcing body portion made of the second molding material includes an uneven surface or an inclined surface,
A partition member having a shape corresponding to the interface is disposed inside the molding die, and the first and second molding materials are supplied to the inside and the outside of the partition member, respectively, and cured. A method for producing a fuel cell separator, wherein the partition member is removed when the molding material 2 is in a semi-cured state. A separator body made of a first molding material having a volume resistivity of 10 mΩ · cm or less, and a reinforcing body portion made of a second molding material having a bending strength of 50 MPa or more provided at the peripheral edge of the separator body; A separator for a fuel cell in which an interface between a separator body made of the first molding material and a reinforcing body portion made of the second molding material includes an uneven surface or an inclined surface,
The first molded body to be the separator main body previously molded from the first molding material in the molding die, or the reinforcing body portion previously molded from the second molding material The second molding material is disposed, and the second molding material or the first molding material is supplied to the outside of the first molding body or the inside of the second molding body to be cured integrally. The manufacturing method of the separator for fuel cells characterized by the above-mentioned.   A fuel cell comprising the fuel cell separator according to claim 1.

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