JP2006252889A - Fuel cell gas diffusion layer member and manufacturing method of same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell gas diffusion layer member 20 excellent in assembling efficiency at assembling a fuel cell and gas sealing property under a condition of operating the fuel cell, and to provide a manufacturing method of the same. <P>SOLUTION: On the fuel cell gas diffusion layer member 20 having a gas sealing member 40 arranged around a gas diffusion layer 13 preventing the gas diffusion layer 13 from leakage of fuel gas and its manufacturing method, the gas sealing member 40 includes a base body 11 made of resin having a load deflecting temperature exceeding a range of fuel cell operation temperature; and a sealing member 12 made of elastomer. At least a part of the surface of the sealing member 12 is integrally molded with the bas body 11. It is preferable that the gas diffusion layer member 20 is formed integrally by two-color molding, and the resin is a crystalline resin. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cell gas diffusion layer member and a method for producing the same.

A fuel cell has a cell as a structural unit, and one cell (single cell) has a structure in which different electrodes (a fuel electrode and an air electrode) sandwich an electrolyte membrane such as a solid polymer.
And a fuel cell generate | occur | produces big electricity by stacking many cells (what is called a stack type).

A conductive porous body having a large contact area with the fuel gas is used for the fuel electrode and the air electrode, and a catalyst layer is provided on the surface on the electrolyte membrane side. Then, hydrogen and air of the fuel gas pass through the conductive porous body (gas diffusion layer).
At this time, an electrode reaction occurs at the fuel electrode and the air electrode due to the action of the catalyst.
On the fuel electrode side, the supplied hydrogen molecules become hydrogen atoms and emit electrons, generating hydrogen ions. The electrons move to the air electrode side through an external circuit provided separately. Thereby, an electric current flows and electricity is generated.
On the other hand, on the air electrode side, oxygen molecules in the supplied air receive the electrons to generate oxygen ions. There, the hydrogen ions move through the electrolyte membrane to the air electrode side, combine with the oxygen ions, and become water. And this water is discharged | emitted out of the system with surplus air.

  Here, in order to increase the power generation efficiency of the fuel cell, it is important to increase the series of reaction efficiencies described above, and therefore it is required to prevent leakage of supplied fuel gas.

On the other hand, conventionally, various proposals have been made to prevent fuel gas leakage.
For example, a gasket having a sealing material impregnated in a gap portion of a sealing portion of a sealing object having a gap portion has been proposed (see Patent Document 1).
A gas diffusion layer; a sheet-like frame member arranged in an extending direction of the end face of the gas diffusion layer; and a rubber-like elastic material that is arranged between the gas diffusion layer and the frame member and integrated with both. A component having a gasket has been proposed (see Patent Document 2).

Further, a gas diffusion layer member is proposed in which a resin frame made of a resin or an elastomer is provided around the conductive porous body, and a groove for an O-ring or a convex portion can be provided on the resin frame with a soft resin ( And a gasket (O-ring) including a carrier member, a seal member, and a stopper member (for preventing the seal member from substantially increasing the width of the gap). (See Patent Document 4).
JP 2004-95565 A JP 2003-7328 A US Patent Application Publication No. 2004/100295 JP 2001-146971 A

However, in the proposal of Patent Document 1, it is difficult to uniformly impregnate the sealing material into the gap portion of the sealing object, and the thin portion of the impregnated portion of the sealing material is cracked due to vibration / impact during the operation of the fuel cell. The strength of the seal portion was low, such as a hole being opened, and the gas sealability was insufficient.
In the proposal of Patent Document 2, an integrated product of a gas diffusion layer, a sheet-like frame member, and a gasket is formed, and these can be handled together as one part, which facilitates assembly and the like. However, the gasket is made of a rubber-like elastic material, and during the operation of the fuel cell, the gasket may be deformed by heat and gas sealing performance may be deteriorated.
Further, in the proposal of Patent Document 3, it is possible to handle the conductive porous body and the resin frame as one component. However, providing a convex portion with a soft resin can cause deformation such as deformation due to heat during operation of the fuel cell. Therefore, the gas sealability may be deteriorated. Furthermore, the use of the O-ring disclosed in Patent Document 4, for example, requires time to install the O-ring when assembling the cell, or the O-ring is twisted due to lack of consistency with the groove provided for the O-ring. There is a problem that it is likely to occur and the assembly efficiency is low.

  The present invention has been made in view of the above problems, and is a gas diffusion layer member for a fuel cell that is excellent in both assembly efficiency when assembling a fuel cell and gas sealability under fuel cell operating conditions, and a method for manufacturing the same. The purpose is to provide.

As a result of intensive studies, the present inventors have found that the above problem can be solved by providing a gas sealing material integrally formed with a resin base and an elastomer sealing material on the peripheral portion of the gas diffusion layer. The headline and the present invention were completed.
That is, the present invention provides a gas diffusion layer member for a fuel cell in which a gas sealing material for preventing leakage of fuel gas from the gas diffusion layer is provided at a peripheral portion of the gas diffusion layer. The substrate is made of a resin having a deflection temperature under the upper limit temperature of the fuel cell operating temperature range and a sealing material made of an elastomer, and the sealing material is integrally formed on at least a part of the surface of the base. This is a gas diffusion layer member for a fuel cell.
Further, the gas diffusion layer member for a fuel cell of the present invention is preferably integrally molded by two-color molding, and the resin is preferably a crystalline resin.
Furthermore, the present invention provides a method for producing a gas diffusion layer member for a fuel cell in which a gas sealing material for preventing leakage of fuel gas from the gas diffusion layer is provided at the periphery of the gas diffusion layer. A gas sealing material is formed by integrally molding a base made of a resin having a temperature equal to or higher than the upper limit temperature of the fuel cell operating temperature range and a sealing material made of an elastomer at least at a part of the surface of the base, and the gas sealing material Is provided at the periphery of the gas diffusion layer at the same time as or after the integral molding, and a method for producing a gas diffusion layer member for a fuel cell.
Here, “provided at the peripheral portion of the gas diffusion layer” means that the gas sealing material is molded so as to surround the periphery extending in the surface direction of the gas diffusion layer.

  ADVANTAGE OF THE INVENTION According to this invention, the gas diffusion layer member for fuel cells which was excellent in both the assembly efficiency at the time of assembling a fuel cell, and the gas-seal property on fuel cell operating conditions can be provided.

Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS.
The gas diffusion layer member 20 for a fuel cell according to the present invention is mainly used in a stack type fuel cell 10 as schematically shown in FIG. 1, and as shown in FIGS. A gas sealing material 40 that is integrally formed on at least a part of the surface of the base 11 is provided on the peripheral edge of the gas diffusion layer 13.
The reference numerals assigned to the fuel cell gas diffusion layer members of the present invention are 20 in FIG. 2 and 30 in FIG. 3, but the same configuration as the embodiment will be denoted by 20 in FIG. Description is omitted.

<Substrate>
The resin used for the substrate 11 is a resin whose deflection temperature under load is equal to or higher than the upper limit temperature of the fuel cell operating temperature range.
Here, the deflection temperature under load refers to a temperature at which a test piece bends a certain distance under a certain bending load under a specific test condition (JIS K 7191). For example, a load of 1.80 MPa is applied to a test piece having a thickness of 4.0 mm, and 120 ° C./hr. And the temperature when the deflection reaches 0.34 mm is measured.
The fuel cell operating temperature refers to the temperature in the gas diffusion layer 13 while the fuel cell 10 is actually operating, and is a unique temperature value for each individual fuel cell device.
The current practical temperature range is generally −20 ° C. to 120 ° C., and the resin used is preferably a resin having a deflection temperature under load of 120 ° C. or higher. As a result, the strength against heat under the fuel cell operating conditions is ensured, the occurrence of deformation and deflection due to heat can be prevented, and the gas sealing property is excellent.

Furthermore, the resin used for the substrate 11 is more preferably a crystalline resin.
Here, the crystalline resin refers to a polymer substance that shows a molecular arrangement with a considerable order and has a clear crystal structure recognized by X-ray diffraction (Rikagaku Dictionary).
Since the resin used for the substrate 11 is a crystalline resin, it has excellent chemical resistance and is less likely to deteriorate due to contact with the electrolyte membrane 15 such as fuel gas or solid polymer. In addition, since the gas permeability of the resin itself is lowered, the gas sealability is further improved.

The resin used for the substrate 11 may be a resin having a deflection temperature under load that is equal to or higher than the upper limit temperature of the fuel cell operating temperature range. Currently, a resin with a deflection temperature under load of 120 ° C. or higher is preferable, among which a thermoplastic resin, It is preferably selected from thermosetting resins.
Thermoplastic resins include ionomer resins, ethylene / ethyl acrylate copolymer resins,
Acrylonitrile / styrene / acrylic rubber copolymer (ASA) resin, acrylonitrile / chlorinated polyethylene / styrene copolymer (ACS) resin, ethylene / vinyl alcohol copolymer resin, acrylonitrile / butadiene / styrene copolymer (ABS) resin, fluorine resin, Polyamide resin, polyacrylate resin, liquid crystal polymer, polyether ether ketone (PEEK) resin, polyether sulfone (PES) resin, polyethylene terephthalate, polycarbonate resin, phenylene ether resin, polyphenylene sulfide (PPS) resin, polybutylene terephthalate ( PBT), polypropylene resin, polymethylpentene,
Examples include syndiotactic polystyrene (SPS).
Examples of the thermosetting resin include an epoxy resin, a phenol resin, a polyimide resin, and a melamine resin.
Among these, the crystalline resin is excellent in chemical resistance and has low gas permeability. Therefore, it is a fluororesin, polyamide resin, liquid crystal polymer, polyether ether ketone (PEEK) resin, polyethylene terephthalate, polyphenylene sulfide (PPS). ) Resin, polybutylene terephthalate (PBT), and polypropylene resin are preferably selected, and among them, polyphenylene sulfide (PPS) resin and polypropylene resin are more preferably selected. These resins may be used alone or in combination of two or more.

In addition to the above-described resin, an inorganic filler can be appropriately added to the substrate 11. The inorganic filler is in a fibrous form and is contained in the substrate 11 in an amount of 5 to 60% by mass or less. Here, the fibrous form means one having an aspect ratio of 5 or more.
The outer diameter of the inorganic filler is 3.5 nm to 30 μm, preferably 3.5 nm to 10 μm. Thereby, an inorganic filler is uniformly disperse | distributed in the molten resin which fuse | melted resin which comprises the base | substrate 11 at a shaping | molding process, and the fluidity | liquidity of this molten resin will become favorable.
For example, when the gas sealing material 40 and the gas diffusion layer 13 are molded, the inorganic filler is entangled with the pores opened at the peripheral edge of the gas diffusion layer 13, and the opening area of the pores is reduced. And since the said molten resin hardens | cures in the site | part, this comes to be able to block | close this pore more reliably. Thereby, the gas sealing property in the junction part of the gas sealing material 40 and the gas diffusion layer 13 will improve more.
Examples of inorganic fillers include fibrous materials such as glass fibers, carbon fibers, carbon nanotubes, and short metal fibers; metal oxides such as aluminum oxide, zirconium oxide, zinc oxide, potassium titanate, and aluminum borate; silicon carbide, aluminum nitride A non-oxide ceramic needle crystal (so-called whisker) substance or the like is used.

As shown in FIGS. 2 to 4, as an embodiment, the base 11 has a fuel supply through hole 21, a fuel discharge through hole 22, and an air supply through hole 31. Each of the through holes 32 for discharging air is provided.
Further, the base 11 can be provided with bolt insertion holes 25 at four corners through which fixing bolts and the like are inserted in order to fix the stacked body of fuel cells.

<Seal material>
The sealing material 12 is selected from elastomers. Among them, an elastomer having a Young's modulus (JIS K 6394) in the fuel cell operating temperature range of 5 × 10 ⁸ Pa or less is preferably selected. Thereby, when assembling the fuel cell or when the fuel cell is operated, it has sufficient elastic force that can absorb vibrations and shocks, and has excellent gas sealing properties.
As will be described in detail below, the sealing material 12 may be integrally formed with the base body 11 and at least a part of the surface of the base body 11, and may be provided only on one side of the base body 11. It may be provided. Further, the position on the surface of the substrate 11 on which the sealing material 12 is provided is arbitrary, and can be provided in a thin seal line, for example, at the position shown in FIG.
In particular, in order to improve gas sealing performance and prevent mixing of hydrogen and air of the fuel gas, in the fuel cell gas diffusion layer member 20 for the fuel electrode, the gas diffusion layer 13 and the air supply through-hole 31 2 and between the gas diffusion layer 13 and the air exhaust through-hole 32, it is preferable to provide the sealing material 12 as shown in FIG. Further, in the fuel cell gas diffusion layer member 30 for the air electrode, between the gas diffusion layer 13 and the fuel supply through hole 21 and between the gas diffusion layer 13 and the fuel discharge through hole 22, It is preferable to provide the sealing material 12 as shown in FIG. As a result, a sealing material is provided so as to surround the through holes 31, 32, 21, and 22.

The elastomer used for the sealing material 12 includes a thermosetting resin having rubber-like elasticity such as a silicone resin; an ethylene / vinyl acetate (EVA) copolymer resin; a thermoplastic resin having rubber-like elasticity such as a polybutadiene resin; and a thermoplastic polyurethane. Examples include elastomers and other thermoplastic elastomers (TPE). Above all, because it is excellent in chemical resistance and heat resistance,
Silicone resins and olefinic thermoplastic elastomers are preferably selected. These elastomers may be used individually by 1 type, or may use 2 or more types together.

<Integrated molding of base and sealing material>
Using the base body 11 and the sealing material 12 described above, the gas sealing material 40 is formed by integrally molding both of them on at least a part of the surface of the base body 11.
By the integral molding, when assembling the fuel cell, the base body 11 and the sealing material 12 can be handled together as one part, and the conventional process of attaching the sealing material 12 to the base body 11 with an adhesive or the like is not necessary. As a result, the mounting time is shortened and the cell assembly efficiency is excellent.
In addition, the fixing strength between the integrally formed base 11 and the sealing material 12 is higher than the fixing strength with a conventional adhesive or the like. As a result, the positional relationship between the base 11 and the sealing material 12 can be kept constant even when the fuel cell is assembled or the vibration / impact at the time of fuel cell operation, and the gas sealing property is excellent. It will be.

The method of integral molding is not particularly limited, and among these, injection molding is preferably used, and among these, two-color molding is more preferably used.
Here, the two-color molding refers to a molding method for producing an integrated product made of two types of resins.
By the two-color molding, the resin of the base 11 and the elastomer of the sealing material 12 are in direct contact with each other in a melted state at the interface, and are fused. Thereby, the integrated object (gas sealing material 40) which the base | substrate 11 and the sealing material 12 adhered firmly is shape | molded.
Further, since the tightening pressure and the like can be controlled, smoothness and thickness fluctuation in the molded product can be prevented, and an integrated product (gas sealing material 40) having a uniform shape can be obtained. Thereby, when stacking cells, it becomes difficult to form a gap, so that the stacking is good and the gas sealability is further improved.
Furthermore, since the position of the sealing material 12 provided on the surface of the base 11 can be arbitrarily and highly accurately formed, the position of the sealing material 12 can be arranged in various patterns and can be used for various fuel cell devices. For example, it is excellent in usability to meet various requirements.

[Two-color molding]
Next, the two-color molding preferably used in the present invention will be described in detail.
For molding, a dedicated machine equipped with two sets of injection devices (mold, cylinder, etc.) is used.
In the integral molding of the base 11 and the sealing material 12, first, the molten resin of the first base 11 is clamped with a primary mold from the first cylinder and injection molded. Next, the mold is opened once, and the mold is closed by rotating the mold turntable 180 degrees while the primary molded product is adhered to the core side.
Next, from the second cylinder, the melt of the second sealant 12 is clamped with a secondary mold and injection molded. Next, the mold is opened again, and the molded product is taken out of the mold, whereby the gas sealing material 40 which is a two-color molded product is molded.
In actual operation, two sets of injection devices are operated almost simultaneously, and one shot of a molded product is obtained every half rotation.
The two-color injection molding machine is generally a system in which the mold is reversed, but a molding machine that employs a core back system of the mold can also be used.

  On the other hand, as a method other than two-color molding, two sets of molds are attached back to back around the vertical axis and half-rotated around the vertical axis, and primary molding and secondary molding in one set of molds For example, a method of providing a set of cavities and cores can be used.

<Gas diffusion layer>
The gas diffusion layer 13 used in the present invention is excellent in conductivity and preferably has a large contact area with the fuel gas. Among them, a conductive porous body is preferably used.
Examples of the conductive porous body include carbon porous bodies such as carbon paper and carbon cloth; metal porous bodies having a three-dimensional network structure, and the like. Among these, a metal porous body is preferably used because both gas diffusibility and conductivity are good.
As the metal porous body, for example, a sheet obtained by sintering a metal powder, a metal nonwoven fabric, a laminated mesh, and the like are preferably used. Among them, the porosity and thickness can be appropriately adjusted, and usable raw metal is also widely used. Therefore, a sheet obtained by sintering metal powder is more preferably used. Above all, since a metal porous body with a high porosity can be produced, a foamed metal obtained by mixing a metal powder, a binder and a solvent and kneading them into a foaming slurry by mixing a foaming agent and sintering after foam molding A sintered sheet is more preferably used.
These conductive porous bodies may be used alone or in combination of two or more.

<Molding of gas sealing material and gas diffusion layer>
As a molding method of the gas sealing material 40 and the gas diffusion layer 13, a method such as insert molding described in Patent Document 3 is preferable at the same time as or after the integral molding of the base body 11 and the sealing material 12 described above. Of these, insert two-color molding, in which two-color molding and insert molding are simultaneously performed, is more preferably used.
For example, the material of the gas diffusion layer 13 is an insert part, and insert molding is performed simultaneously with two-color molding when the gas sealing material 40 is molded. The gas diffusion layer member 20 for a fuel cell provided in is formed.
This ensures that the gas diffusion layer 13 has a gas seal by being impregnated with the molten resin or the like of the material constituting the gas sealing material 40 and being cured in the pores opened in the peripheral portion of the gas diffusion layer 13. Can do. Moreover, the gas sealing material 40 and the gas diffusion layer 13 can be firmly joined by the anchor effect. Thereby, the strength of the gas diffusion layer 13 can be increased, and the gas sealing material 40 and the gas diffusion layer 13 can be handled as one component, so that the fuel cell assembly efficiency is excellent.

In addition, said "the gas sealing material 40 was provided in the peripheral part of the gas diffusion layer 13" means that the gas sealing material 40 is shape | molded so that the circumference extended in the surface direction of the gas diffusion layer 13 may be enclosed. Say.
In addition, “simultaneously with or after the integral molding” means that the gas diffusion layer 13 is insert-molded or integrally molded simultaneously with the integral molding of the base 11 and the sealing material 12 when the gas sealing material 40 is molded. This means that the gas diffusion layer 13 is insert-molded with respect to the gas sealing material 40, which is different from the conventional method of separately providing the sealing material 12 or the O-ring on the surface of the base 11.

The gas diffusion layer member 20 for a fuel cell manufactured according to the present invention is such that the gas sealing material 40 is provided at the peripheral edge of the gas diffusion layer 13 and further includes other fuel cell components. Good.
According to the present invention, for example, as shown in FIG. 5, the gas sealing material 40 is a fuel cell gas provided at the peripheral portion of the fuel cell component in which the gas diffusion layer 13 and the separator 14 are joined by hot pressing or the like. Further, it may be a diffusion layer member. Further, the peripheral portion of the fuel cell component in which the gas sealing material 40 is joined to a pair of gas diffusion layers and an electrolyte membrane 15 such as a solid polymer sandwiched between the gas diffusion layers. It may be a gas diffusion layer member for a fuel cell provided in the above.

  Hereinafter, the present invention will be described in more detail with reference to FIGS. 6 to 9 using examples, but the present invention is not limited to these examples.

The fuel cell gas diffusion layer members shown in Examples 1 and 2 and Comparative Examples 1 to 3 were manufactured for use in fuel cells having a fuel cell operating temperature range of -20 ° C to 120 ° C.
The gas diffusion layer member for a fuel cell was manufactured having a length of 40 mm, a width of 40 mm, and a thickness of 0.5 mm. The base in the gas sealing material provided at the peripheral edge of the gas diffusion layer has a width of 7.5 mm and a thickness of 0.5 mm, and the sealing material has a width of 0.3 mm and a thickness of 0.3 mm at the position shown in FIG. It shape | molded so that it might become.
When the O-ring was used, it was fixed on the surface of the base so as to be in the same position as in FIG.

Example 1
FIG. 6 shows a gas diffusion layer (foamed metal sintered sheet) 53 as an insert part, and insert molding is performed simultaneously with two-color molding when the base 51 and the sealing material 52 made of the following materials are integrally molded. As described above, the fuel cell gas diffusion layer member 50 in which the gas sealing material 54 was provided on the periphery of the gas diffusion layer (foamed metal sintered sheet) 53 was manufactured.
<Materials used for base and sealing material>
-Substrate: Polypropylene (deflection temperature of load 121 ° C, crystalline resin)
Sealing material: Thermoplastic olefin-based elastomer (Young's modulus 5 × 10 ⁵ Pa)

(Example 2)
A gas diffusion layer member for a fuel cell was produced in the same manner as in Example 1 except that the material used for the substrate was changed to polystyrene (load deflection temperature 60 ° C., amorphous resin).

(Comparative Example 1)
A gas diffusion layer member for a fuel cell was produced in the same manner as in Example 1 except that the material used for the sealing material was changed to a polycarbonate (Young's modulus 3 × 10 ⁹ Pa) different from the elastomer.

(Comparative Example 2)
A base 61 made of the following material and a gas diffusion layer (foamed metal sintered sheet) 63 are insert-molded, and a gas sealing material consisting only of the base 61 is applied to the peripheral portion of the gas diffusion layer 63 as shown in FIG. The provided fuel cell gas diffusion layer member 60 was manufactured. Separately, the following O-ring 80 was prepared.
<Materials used for base and O-ring>
-Substrate: Polypropylene (deflection temperature of load 121 ° C, crystalline resin)
・ O-ring: Fluoro rubber (Standard S38, inner diameter 37.5mm, thickness 2mm)

(Comparative Example 3)
A gas composed only of a base 71 in which a base 71 made of the following material and a gas diffusion layer (foamed metal sintered sheet) 73 are insert-molded and an O-ring fixing groove is formed on the surface of the base 71 as shown in FIG. A fuel cell gas diffusion layer member 70 in which a sealing material was provided on the peripheral edge of the gas diffusion layer 73 was manufactured. Separately, the following O-ring 80 was prepared.
<Materials used for base and O-ring>
-Substrate: Polypropylene (deflection temperature of load 121 ° C, crystalline resin)
・ O-ring: Fluoro rubber (Standard S38, inner diameter 37.5mm, thickness 2mm)

<Evaluation method>
Using the fuel cell gas diffusion layer member and the O-ring 80 manufactured in the example and the comparative example, the assembly efficiency when assembling the laminate of the fuel cell gas diffusion layer member instead of the fuel cell, and the lamination The gas sealing property under the fuel cell operating conditions of the body was evaluated by the following method.

(Assembly efficiency)
The operation of assembling the stack of fuel cell gas diffusion layer members 91 shown in FIG. 9 was performed as follows.
In Example 1, Example 2, and Comparative Example 1, a laminated body in which 10 manufactured fuel cell gas diffusion layer members 91 were stacked in the guide pin insertion hole 55 through the guide pins 93 was manufactured, and both sides of the laminated body were manufactured. The surfaces were sandwiched between fixing metal plates 92 and fastened at 1 MPa in the direction of the arrow.
In Comparative Example 2 and Comparative Example 3, the O-ring 80 is fixed to the surface of the base body of the manufactured fuel cell gas diffusion layer member 91 with an adhesive so as to be in the same position as the sealing material shown in FIG. A fuel cell gas diffusion layer member 91 is produced by stacking 10 pieces of the gas diffusion layer members 91 in the guide pin insertion holes 55 through the guide pins 93, and both side surfaces of the laminate are sandwiched between the fixing metal plates 92, in the direction of the arrow. Fastened at 1 MPa.
The time required for this work was measured as the assembly time (minutes), and the assembly efficiency was evaluated according to the following criteria.
○: Less than 30 minutes ×: 30 minutes or more

(Gas sealability)
Hydrogen gas was allowed to flow through the above-mentioned laminated body for a certain period of time, valve 1 (94) and valve 2 (95) were closed, and the inside of the laminated body was set to 25 ° C. and an initial pressure of 100 kPa.
This condition was maintained, and after storing at −20 ° C. for 2 hours, the operation of storing at 120 ° C. for 2 hours was repeated 3 cycles (12 hours in total).
Then, the pressure in this laminated body was measured with the pressure gauge 96 at 25 degreeC, the difference with an initial stage pressure was calculated | required, and the gas-sealing property was evaluated on the following reference | standard.
○: Less than 2 MPa Δ: 2 MPa or more and less than 5 MPa ×: 5 MPa or more

From Table 1, Example 1 in which the deflection temperature under load applied to the substrate 51 is equal to or higher than the upper limit temperature of the fuel cell operating temperature range and the elastomer is used as the sealing material 52 has good assembly efficiency and gas sealability. It was. In addition, it was confirmed that Example 1 was superior in gas sealability to Example 2 in which an amorphous resin was used for the substrate.
On the other hand, in Comparative Example 1 where no elastomer was used as the sealing material, it was confirmed that the gas sealability was poor. Further, it was confirmed that Comparative Example 2 and Comparative Example 2 in which the O-ring 80 was fixed with an adhesive, rather than integrally molding the sealing material with the base body, had poor assembly efficiency and gas sealability. . In Comparative Example 3, it was confirmed that the assembly efficiency was poor and the gas sealing property was inferior.
As described above, the gas sealing material 40 provided at the peripheral portion of the gas diffusion layer 13 includes the base body 11 made of a resin having a deflection temperature under the upper limit temperature of the fuel cell operating temperature range, and the sealing material 12 made of an elastomer. The gas diffusion layer member 20 for a fuel cell according to the present invention, in which the sealing material 12 is integrally formed on at least a part of the surface of the base 11, has the assembly efficiency and fuel cell operating conditions when assembling the fuel cell. It was confirmed that the gas-sealing property was excellent.

It is an example of a stack type fuel cell, and is a sectional view thereof. It is an example of the gas diffusion layer member for fuel cells for fuel electrodes in FIG. 1, and is the top view (a) and sectional drawing (b) in alignment with the AA in FIG. 2 (a). It is an example of the gas diffusion layer member for fuel cells for air electrodes in FIG. 1, and is the top view (a) and sectional drawing (b) which follows the AA line in FIG. 3 (a). It is sectional drawing (b) which follows the top view (a) of the gas sealing material in FIG. 2, and the AA line in FIG. 4 (a). It is sectional drawing of one Embodiment of the gas diffusion layer member for fuel cells provided in the peripheral part of the fuel cell component with which the gas diffusion layer and the separator joined. It is sectional drawing (b) which follows the AA line in the top view (a) and FIG. 6 (a) of the gas diffusion layer member for fuel cells by Example 1 of this invention. 8A is a plan view of a fuel cell gas diffusion layer member and an O-ring according to Comparative Example 2, and FIG. 7B is a cross-sectional view of the fuel cell gas diffusion layer member taken along line AA in FIG. 9A is a plan view of a fuel cell gas diffusion layer member and an O-ring according to Comparative Example 3, and FIG. 8B is a cross-sectional view of the fuel cell gas diffusion layer member taken along line AA in FIG. It is a schematic diagram which shows the evaluation apparatus for evaluating the gas-seal property of the laminated body of the gas diffusion layer member for fuel cells.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Stack type fuel cell 11 Base body 12 Sealing material 13 Gas diffusion layer 14 Separator 15 Electrolyte membrane 20 Gas diffusion layer member for fuel cell for fuel electrode 21 Through hole for fuel supply 22 Through hole for fuel discharge 25 Bolt insertion hole 30 Gas diffusion layer member for fuel cell for air electrode 31 Through hole for supplying air 32 Through hole for discharging air 40 Gas sealing material 50 Gas diffusion layer member for fuel cell 51 Base 52 Sealing material 53 Gas diffusion layer 54 Gas sealing Stop material 55 Guide pin insertion hole 56 Fuel supply through hole 57 Fuel discharge through hole 58 Air supply through hole 59 Air discharge through hole 60 Gas diffusion layer member for fuel cell 61 Base 63 Gas diffusion layer 70 Gas diffusion layer member for fuel cell 71 Base 73 Gas diffusion layer 80 O-ring 90 Evaluation device 91 Gas diffusion layer member for fuel cell 92 Fixing Metal plate 93 Guide pin 94 Valve 1
95 Valve 2
96 Pressure gauge

Claims (4)

  In a gas diffusion layer member for a fuel cell in which a gas sealing material for preventing fuel gas leakage from the gas diffusion layer is provided at a peripheral portion of the gas diffusion layer, the gas sealing material has a deflection temperature under load of fuel. A fuel cell comprising a base made of a resin having an upper limit temperature of a battery operating temperature range and a sealing material made of an elastomer, wherein the sealing material is integrally formed on at least a part of the surface of the base. Gas diffusion layer member.   The gas diffusion layer member for a fuel cell according to claim 1, which is integrally formed by two-color molding.   The gas diffusion layer member for a fuel cell according to claim 1 or 2, wherein the resin is a crystalline resin. In a method for manufacturing a gas diffusion layer member for a fuel cell in which a gas sealing material for preventing leakage of fuel gas from the gas diffusion layer is provided at the peripheral edge of the gas diffusion layer, the deflection temperature under load is a fuel cell operating temperature range A base material made of a resin having a temperature equal to or higher than the upper limit temperature and a sealing material made of an elastomer are integrally formed on at least a part of the surface of the base material to form a gas sealing material. A method for producing a gas diffusion layer member for a fuel cell, characterized in that the gas diffusion layer member is provided at a peripheral portion of the gas diffusion layer simultaneously or later.

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