JP2023094638A - Manufacturing method of sealing material - Google Patents

Abstract

To provide a manufacturing method of a sealing material capable of suppressing occurrence of peeling of adhesive between the sealing material and parts such as separators.SOLUTION: A manufacturing method of a sealing material for fuel cells by slicing a block material with openings to a predetermined thickness includes: a step of preparing the block material: and a step of slicing the block material in a direction perpendicular to the thickness direction of the block material to obtain the sealing material. In the step of obtaining the sealing material, at least one surface of the sealing material is roughened, and the formation of the roughness is performed by sliding at least one selected from the group consisting of the blade and the block material during the slice.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a method for manufacturing a sealing material.

Various techniques have been proposed for sealing materials for fuel cells.
For example, in Patent Document 1, a fuel cell frame member having excellent insulation properties, high corrosion resistance, low impurity elution, excellent sealability (adhesiveness), and high strength and durability is manufactured in a simple manner. A method is disclosed.
In Patent Document 2, the surface of a carbon plate molded product with a thermosetting resin as a binder is irradiated with a laser to bake the surface, thereby improving the adhesive strength between the gasket and the carbon plate that are adhered to the surface. A surface treatment method for the purpose is disclosed.

JP 2014-135145 A JP 2004-158346 A

Conventionally, as a method of manufacturing a sealing material for a fuel cell, a block material (thickness 30 to 100 mm) having the same shape as that of the sealing material having an opening is cut with a blade such as a rotating blade or a press cutting blade (thickness 0.5 mm). By slicing it into pieces of about 100 mm, a sealing material for a fuel cell is manufactured.
In the prior art, a sealing material obtained by slicing a block material and parts such as a separator are adhered using an adhesive. After applying adhesive to the flat surface of the sealing material, the adhesive flows out from the surface of the sealing material. As a result, the adhesion between the sealing material and the parts such as the separator is peeled off, and reaction gas and cooling water leak from the sealing portions of the fuel cell in the unit cells and between the unit cells.

The present disclosure has been made in view of the above circumstances, and a main object of the present disclosure is to provide a method of manufacturing a sealing material that can suppress the occurrence of peeling of adhesion between the sealing material and parts such as separators.

In the present disclosure, a method for manufacturing a sealing material for a fuel cell by slicing a block material having an opening into a predetermined thickness, comprising:
preparing the block material;
obtaining a sealing material by slicing the block in a direction perpendicular to the thickness direction of the block;
In the step of obtaining the sealing material, unevenness is imparted to at least one surface of the sealing material,
Provided is a method for producing a sealing material, wherein the unevenness is provided by sliding at least one selected from the group consisting of a blade and the block during the slicing.

The method for manufacturing a sealing material according to the present disclosure can suppress the occurrence of debonding between the sealing material and a part such as a separator.

FIG. 1 is a schematic diagram showing, from the left, an example of a conventional flat surface sealing material and an example of a sealing material having an adhesive applied to the flat surface. FIG. 2 is a schematic diagram showing an example of a block material, a sealing material obtained by slicing the block material to provide unevenness on one surface, and a sealing material obtained by applying an adhesive to the uneven surface. .

Embodiments according to the present disclosure will be described below. It should be noted that matters other than matters specifically mentioned in this specification and necessary for the implementation of the present disclosure (for example, the general configuration and manufacturing process of sealing materials that do not characterize the present disclosure) It can be grasped as a design matter of a person skilled in the art based on the prior art in. The present disclosure can be implemented based on the content disclosed in this specification and common general technical knowledge in the field.
Also, the dimensional relationships (length, width, thickness, etc.) in the drawings do not reflect the actual dimensional relationships.
In the present specification, the term "to" indicating a numerical range is used to include the numerical values before and after it as lower and upper limits.
Any combination of the upper limit and the lower limit in the numerical range can be adopted.

In the present disclosure, a method for manufacturing a sealing material for a fuel cell by slicing a block material having an opening into a predetermined thickness, comprising:
preparing the block material;
obtaining a sealing material by slicing the block in a direction perpendicular to the thickness direction of the block;
In the step of obtaining the sealing material, unevenness is imparted to at least one surface of the sealing material,
Provided is a method for producing a sealing material, wherein the unevenness is provided by sliding at least one selected from the group consisting of a blade and the block during the slicing.

FIG. 1 is a schematic diagram showing, from the left, an example of a conventional flat surface sealing material and an example of a sealing material having an adhesive applied to the flat surface.
As shown in Fig. 1, when adhesive is applied to a conventional flat surface sealing material, the adhesive flows out, resulting in areas where the amount of adhesive applied is less than expected, resulting in poor adhesion between the sealing material and parts such as separators. The area is reduced, and adhesion peeling occurs between the sealing material and parts such as separators.

FIG. 2 is a schematic diagram showing an example of a block material, a sealing material obtained by slicing the block material to provide unevenness on one surface, and a sealing material obtained by applying an adhesive to the uneven surface. .
As shown in FIG. 2, by forming unevenness on at least one surface of the sealing material when slicing the block material, when the sealing material and parts such as separators are pressure-bonded with an adhesive, the unevenness of the sealing material causes This makes it difficult for the adhesive to flow out, increases the bonding area between the sealing material and parts such as separators, and suppresses the occurrence of peeling of the adhesive between the sealing material and parts such as separators. The uneven cross-section of the sealing material may be one of the two structures shown on the right upper and lower sides of FIG. It may be a structure or the like that has a

According to the present disclosure, at least one surface of the sealing material is roughened during slicing of the block and optionally after slicing the block.
According to the present disclosure, when the sealing material and parts such as separators are pressure-bonded using an adhesive, the unevenness of the sealing material makes it difficult for the adhesive to flow out, and the bonding area between the sealing material and parts such as separators increases. , the occurrence of debonding between the sealing material and parts such as separators is suppressed. As a result, it is possible to reduce the occurrence of reaction gas and cooling water leakage from the sealing portion of the fuel cell.

The manufacturing method of the sealing material of the present disclosure includes the steps of (1) preparing a block material, and (2) slicing the block material in a direction perpendicular to the thickness direction of the block material to obtain a sealing material. have a process.

(1) Step of Preparing Block Material The block material to be prepared has openings.
The block material can be produced by mold molding.
Block materials include rubber materials such as ethylene propylene diene rubber (EPDM), silicon rubber, fluororubber, and urethane rubber, olefin-based or styrene-based thermoplastic elastomer resins, and metal materials such as SUS and Ti. may be
The thickness of the block material is not particularly limited, and may be, for example, 30 to 100 mm.

(2) A step of slicing the block material in a direction perpendicular to the thickness direction of the block material to obtain a sealing material In the step of obtaining the sealing material, at least one surface of the sealing material is provided with unevenness. .
The unevenness is imparted by sliding at least one selected from the group consisting of blades and blocks during slicing.
As for the method of slicing the block material, slicing may be performed with a blade such as a rotating blade or a press cutting blade.
As a method for imparting unevenness, there is a method of scraping the sealing material by sliding at least one of the blade and the block material, a method of scraping the sealing material by laser irradiation to make a recess, a method of cutting the sealing material with an ultrasonic cutter ( The width of the blade corresponds to the concave).
Concavo-convex imparting to the sealing material is mainly performed by sliding the blade at the time of slicing and at least one of the blocks. It may be used to impart unevenness to the sealing material.
In the step of obtaining the sealing material, at least one surface of the sealing material may be provided with unevenness, and both surfaces may be provided with unevenness from the viewpoint of improving the sealing performance of the fuel cell. When providing unevenness on both sides, the sealing material obtained at the first slicing of the block and the sealing material at the end of the block obtained at the last slicing have unevenness on only one side. Concavities and convexities may also be imparted to the other surface using a blade, laser, ultrasonic cutter, or the like.
The thickness (slice thickness) of the sealing material can be appropriately set according to the desired thickness of the sealing material, and may be, for example, about 0.5 mm.

The sealing material of the present disclosure is for fuel cells.
Seals of the present disclosure may be used as gaskets, support frames, and the like.

The fuel cell may have only one single cell, or may be a fuel cell stack in which multiple single cells are stacked. The number of stacked single cells is not particularly limited, and may be from two to several hundred.

A single cell includes a cathode separator having an oxidant gas channel, a membrane electrode gas diffusion layer assembly, a support frame, and an anode separator having a fuel gas channel.
In the present disclosure, fuel gas and oxidant gas are collectively referred to as reaction gas. The reactant gas supplied to the anode is fuel gas, and the reactant gas supplied to the cathode is oxidant gas. The fuel gas is a gas containing primarily hydrogen and may be hydrogen. The oxidant gas may be oxygen, air, dry air, or the like.

A membrane electrode gas diffusion layer assembly (MEGA) has an anode-side gas diffusion layer, an anode catalyst layer, an electrolyte membrane, a cathode catalyst layer, and a cathode-side gas diffusion layer in this order.

The cathode (oxidant electrode) includes a cathode catalyst layer and a cathode-side gas diffusion layer.
The anode (fuel electrode) includes an anode catalyst layer and an anode-side gas diffusion layer.
The cathode catalyst layer and the anode catalyst layer are collectively referred to as catalyst layers.

The cathode-side gas diffusion layer and the anode-side gas diffusion layer are collectively referred to as gas diffusion layers or diffusion layers.
The gas diffusion layer may be a conductive member or the like having gas permeability.
Examples of the conductive member include porous carbon bodies such as carbon cloth and carbon paper, and porous metal bodies such as metal mesh and metal foam.

A single cell may have a microporous layer (MPL) between the catalyst layer and the gas diffusion layer. The microporous layer may contain a mixture of a water-repellent resin such as PTFE and a conductive material such as carbon black.

The electrolyte membrane may be a solid polymer electrolyte membrane. Examples of solid polymer electrolyte membranes include fluorine-based electrolyte membranes such as perfluorosulfonic acid thin films containing water, and hydrocarbon-based electrolyte membranes. As the electrolyte membrane, for example, a Nafion membrane (manufactured by DuPont) may be used.

Anode separators and cathode separators are collectively referred to as separators.
A membrane electrode gas diffusion layer assembly is sandwiched between an anode separator and a cathode separator.
The separator may have a plurality of through-holes for circulating reaction gas and fluid such as coolant in the stacking direction of the unit cells. Examples of the through holes include an oxidant gas supply hole, an oxidant gas discharge hole, a fuel gas supply hole, a fuel gas discharge hole, a coolant supply hole, a coolant discharge hole, and the like.
In the fuel cell, a manifold may be formed by connecting a plurality of through holes of the same kind in the stacking direction.
The separator may be a gas-impermeable conductive member or the like. As the conductive member, for example, a carbon composite material obtained by press-molding a mixture containing a thermosetting resin, a thermoplastic resin, a resin material such as resin fiber, carbon powder, and a carbon material such as carbon fiber, or a carbon composite material. It may be a dense carbon made gas-impermeable by heating, or a press-molded metal (eg, titanium, iron, aluminum, SUS, etc.) plate. Also, the separator may have a current collecting function.
The shape of the separator may be a rectangle, a horizontally long hexagon, a horizontally long octagon, a circle, an oblong shape, and the like.
The separator may have reaction gas channels on the surface in contact with the gas diffusion layer. Further, the separator may have a coolant channel for keeping the temperature of the fuel cell constant on the surface opposite to the surface in contact with the gas diffusion layer.
The separator may have a gas distribution section. The gas distribution section is a section that is arranged in a region between the reaction gas manifold and the reaction gas flow path and spreads or converges the gas flow from the reaction gas manifold to the power generation region. The gas distribution section has a structure that widens the gas flow on the reaction gas inlet side. The gas distribution section has a structure that converges the gas flow on the reaction gas outlet side.

The support frame may be arranged around the periphery of the membrane electrode gas diffusion layer assembly and between the cathode separator and the anode separator.
The support frame may have a skeleton, openings, and through holes.
The skeleton is the main part of the support frame that connects with the membrane electrode gas diffusion layer assembly.
The opening is a holding area for the membrane electrode gas diffusion layer assembly, and is an area penetrating a part of the framework for housing the membrane electrode gas diffusion layer assembly. The opening may be arranged in the support frame at a position where the skeleton is arranged around (periphery) the membrane electrode gas diffusion layer assembly, and may be provided in the center of the support frame.
The through-holes of the support frame allow reactant gas and fluid such as coolant to flow in the stacking direction of the unit cells. The through holes of the support frame may be aligned and arranged to communicate with the through holes of the separator.
The material of the support frame may be the same as the material of the blocks.
The support frame may be the seal of the present disclosure.

The fuel cell may include a gasket that seals reactant gas and fluid such as coolant between two adjacent single cells.
The gasket material may be the same as the block material.
A gasket may be the sealant of the present disclosure.

Claims (1)

A method of manufacturing a sealing material for a fuel cell by slicing a block material having openings into a predetermined thickness, the method comprising:
preparing the block material;
obtaining a sealing material by slicing the block in a direction perpendicular to the thickness direction of the block;
In the step of obtaining the sealing material, unevenness is imparted to at least one surface of the sealing material,
The method for producing a sealing material, wherein the unevenness is provided by sliding at least one member selected from the group consisting of a blade and the block during the slicing.

Images