JP2005302526A - Solid polymer electrolyte membrane and membrane electrode assembly having solid polymer electrolyte membrane - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid polymer electrolyte membrane and a membrane electrode assembly having the solid polymer electrolyte membrane wherein dimensional stability and mechanical strength are superior, manufacturing cost is reduced, and a high productivity is exerted. <P>SOLUTION: The solid polymer electrolyte membrane 111 which has a porous sheet 113 in order to reinforce the solid polymer electrolyte membrane 111 itself, and numerous numbers of through-holes 117 are formed in the porous sheet 113. At this time, the through-holes 117 are formed intensively at the center region 121, while the through-holes 117 are not formed at the peripheral region 122, or its aperture rate becomes lower than that in the center region 121 even if the through-holes 117 are formed. Then, a gasket 150 is mounted on the part with which the catalyst layers 127, 128 among the solid polymer electrolyte membranes 111 having the porous sheet 113 are not joined. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a solid polymer electrolyte membrane and a membrane electrode assembly having a solid polymer electrolyte membrane, and in particular, has excellent dimensional stability and mechanical strength, reduces manufacturing costs, and exhibits high productivity. The present invention relates to a solid polymer electrolyte membrane and a membrane electrode assembly having a solid polymer electrolyte membrane.

  Conventionally, separation membranes made of various ion exchange membranes have been used in various fields. An ion exchange membrane, which is a kind of separation membrane, is also used as a solid polymer electrolyte membrane in solid polymer fuel cells that have been actively developed in recent years. Since this polymer electrolyte fuel cell has a high output density and a low operating temperature, it can be miniaturized, so it is widely used for mobile objects such as automobiles, distributed power generation systems, and household cogeneration systems. It is expected that.

A cross-sectional view of a conventional unit cell for a fuel cell is shown in FIG.
In FIG. 8, a unit cell 1 for a fuel cell has a solid polymer electrolyte membrane 11. The solid polymer electrolyte membrane 11 generally has a thickness of about 20 to 120 μm, and a cation exchange membrane made of a perfluorocarbon polymer having a chemically stable sulfonic acid group is used. Yes.
Further, catalyst layers 27 and 28 containing a metal catalyst are joined to both outer surfaces 11a of the solid polymer electrolyte membrane 11, respectively. The catalyst layers 27 and 28 are formed at the central portion of the solid polymer electrolyte membrane 11, and a portion where the catalyst layers 27 and 28 are not joined is left around the catalyst layers 27 and 28.

  The solid polymer electrolyte membrane 11 and the catalyst layers 27 and 28 constitute a membrane catalyst layer assembly 31, and both outer surfaces 31 a on the catalyst layers 27 and 28 side of the membrane catalyst layer assembly 31. Are provided with gas diffusion layers 33 and 34, respectively. The gas diffusion layers 33 and 34 have a size that just covers the catalyst layers 27 and 28 provided on the solid polymer electrolyte membrane 11, and are made of carbon paper, carbon cloth, or the like.

  The membrane / catalyst layer assembly 31 and the gas diffusion layers 33 and 34 constitute a membrane / electrode assembly 37, and both outer surfaces of the membrane / electrode assembly 37 on the gas diffusion layers 33 and 34 side. Gas flow paths 47 and 48 are formed between the separators 41 and 42 in the 37a. At this time, the separators 41 and 42 have a size that covers the entire surface of the solid polymer electrolyte membrane 11, and concave grooves 45 and 46 are engraved in portions facing the catalyst layers 27 and 28, respectively. Yes. The grooves 45 and 46 form gas flow paths 47 and 48 when the separators 41 and 42 and the membrane electrode assembly 37 are tightened. Further, in the separators 41 and 42, gaskets 53 and 54 are arranged on the part of the membrane electrode assembly 37 that faces the part where the catalyst layers 27 and 28 are not joined, and the separators 41 and 42 and the membrane electrode are arranged. When the joined body 37 is tightened, it is interposed between the separators 41 and 42 and the solid polymer electrolyte membrane 11 to seal the gas flow paths 47 and 48 from the outside.

  As described above, the unit cell 1 which is the minimum unit of power generation of the fuel cell is configured. When this unit cell 1 is used for a fuel cell, a unit cell 1 is generated in order to generate a practical voltage. Are stacked and stacked for use.

In such a configuration, hydrogen is supplied to the anode side of the unit cell 1. On the other hand, oxygen or air is supplied to the cathode side. At this time, supply of hydrogen, oxygen, and air is performed through the gas flow paths 47 and 48. As a result, a reaction of H ₂ → 2H ⁺ + 2e ⁻ occurs on the anode side. On the other hand, the reaction of 1 / 2O ₂ + 2H ⁺ + 2e ⁻ → H ₂ O occurs on the cathode side. Thereby, in the fuel cell having the single cell 1, chemical energy can be converted into electric energy.

  However, such a solid polymer electrolyte membrane 11 may change in size depending on the moisture content. Further, the mechanical strength of the solid polymer electrolyte membrane 11 was not sufficient. Therefore, as a technique for reinforcing the solid polymer electrolyte membrane 11, it has been proposed to use a membrane in which a polytetrafluoroethylene (hereinafter referred to as PTFE) porous membrane is impregnated with a fluorinated ion exchange polymer having a sulfonic acid group. (See Patent Document 1). It has also been proposed to use a cation exchange membrane reinforced with a fibril-like, woven or non-woven perfluorocarbon polymer (see Patent Document 2). However, even in such a reinforced membrane, the corners of the outer edge portions 33a, 34a of the gas diffusion layers 33, 34 are in contact with the membrane catalyst layer assembly 31 (this contact portion is defined as a portion 31b). The membrane catalyst layer assembly 31 may be broken due to stress concentration from the corners.

  In addition, when the gaskets 53 and 54 are attached when the conventional unit cell 1 is manufactured, the gaskets 53 and 54 are attached in advance to the separators 41 and 42 as shown in FIG. This is done depending on whether it is press-fitted between the membrane 11 and the separators 41 and 42 or is attached in advance to the solid polymer electrolyte membrane 11 side. However, as described above, since the dimensions of the solid polymer electrolyte membrane 11 change depending on the moisture content, it is difficult to attach the gaskets 53 and 54 to the solid polymer electrolyte membrane 11, and the gaskets 53 and 54 are not attached. Even when the gaskets are attached, the gaskets 53 and 54 may be displaced, which may cause gas leakage and the like. For this reason, the manufacturing cost of the single cell 1 may increase, and there may be a problem in productivity during mass production.

  Therefore, in order to prevent such breakage of the solid polymer electrolyte membrane 11 and the like and to easily attach the gaskets 53 and 54, a central portion is provided in the peripheral region of the membrane electrode assembly 37 that does not require ionic conductivity. It has been proposed to arrange a frame-shaped reinforcing film obtained by cutting out a frame (see Patent Document 3). As a result, the corners of the gas diffusion layers 33 and 34 come into contact with the frame-shaped reinforcing film, so that the solid polymer electrolyte membrane 11 and the like can be prevented from being broken, and the reinforcing film Since the gaskets 53 and 54 can be attached to each other, the gaskets 53 and 54 can be easily attached. However, in this case, in the manufacturing process of the unit cell 1, the number of steps for disposing a frame-shaped reinforcing film in the peripheral region of the membrane electrode assembly 37 increases, which may increase the manufacturing cost. There was a risk of problems in productivity during mass production.

Japanese Patent Publication No. 5-75835 (Claims) Japanese Examined Patent Publication No. 6-231777 (Claim 1, Example 1) Japanese Patent No. 3052536 (Claim 1, Example 1)

  The present invention has been made in view of the above-described conventional problems, and is a solid polymer electrolyte membrane and a solid high electrolyte that are excellent in dimensional stability and mechanical strength, can reduce manufacturing costs, and can exhibit high productivity. An object of the present invention is to provide a membrane electrode assembly having a molecular electrolyte membrane.

  For this reason, the present invention relates to a solid polymer electrolyte membrane, and has a filling layer composed of a porous sheet in which a plurality of through-holes are formed and an ion exchange resin filled in the through-holes. And a second region in which the through hole is not formed or the aperture ratio due to the through hole is lower than the aperture ratio in the first region and located in the outer peripheral portion of the first region. And an elastic body is arranged so as to surround at least the first region in the second region on at least one side.

The solid polymer electrolyte membrane has a filling layer composed of a porous sheet in which a plurality of through holes are formed and an ion exchange resin (for example, a filling portion) filled in the through holes. Therefore, the solid polymer electrolyte membrane is reinforced by the porous sheet. Moreover, in the 2nd area | region of a perforated sheet, the through-hole is not formed or the opening rate by a through-hole is lower than the opening rate in a 1st area | region. For this reason, the tear strength and tensile strength in the second region are improved. Therefore, the mechanical strength and dimensional stability of the solid polymer electrolyte membrane can be improved.
The solid polymer electrolyte membrane may be composed of a single porous sheet, but may be composed of a plurality of laminated porous sheets.

Further, an elastic body is disposed so as to surround at least the first region in the second region on at least one side of the solid polymer electrolyte membrane. Therefore, this elastic body can be sealed from the outside.
Moreover, this elastic body is formed using methods, such as application | coating, a shaping | molding, injection molding, etc., for example, and is integrated with respect to a solid polymer electrolyte membrane. Therefore, it is difficult for the elastic body to be displaced, and gas leakage and the like associated therewith can be prevented. Therefore, the manufacturing cost of the solid polymer electrolyte membrane can be reduced, and the productivity during mass production can be improved.

  Furthermore, since the elastic body can be formed using a method such as coating, molding, injection molding, etc., the elastic body can be easily attached to the solid polymer electrolyte membrane. Therefore, there is no need to perform a step of arranging a frame-like reinforcing membrane in the peripheral region of the solid polymer electrolyte membrane as in the prior art, so this step can be omitted and the manufacturing cost of the solid polymer electrolyte membrane is reduced. Thus, productivity at the time of mass production can be improved.

  The present invention also relates to a solid polymer electrolyte membrane, wherein a layer made of only an ion exchange resin is disposed on at least one surface of the packed layer.

  This can improve the conductivity of the solid polymer electrolyte membrane. At this time, the ion exchange resin constituting this layer may be the same as or different from the ion exchange resin constituting the packed layer. When using different types of ion exchange resins, the strength of the layer itself can be increased by using, for example, an ion exchange resin having a higher strength than the ion exchange resin constituting the packed layer, even if the ion exchange capacity is low. Can do.

  Furthermore, the present invention relates to a solid polymer electrolyte membrane, wherein a manifold hole is formed in the second region.

  Since the manifold hole is formed in the second region where the tear strength and the tensile strength are improved, the manifold hole can prevent the strength of the solid polymer electrolyte membrane from being lowered.

Furthermore, the present invention relates to a solid polymer electrolyte membrane, wherein the through-holes in the first region have an average area of 1 × 10 ^{−3 to} 20 mm ² , and the first region has an aperture ratio. 30 to 80%.

If the average area per through hole is too small, the number of through holes per unit area will be very large if the aperture ratio is kept within a certain range, resulting in low productivity or ion exchange resin. It may be difficult to fill with. On the other hand, if the average area per through hole is too large, the obtained solid polymer electrolyte membrane cannot be uniformly reinforced, and as a result, its strength may be insufficient. Therefore, if the average area per through hole is 1 × 10 ^{−3 to} 20 mm ² , the solid polymer electrolyte membrane can be given practically uniform and sufficient strength, and the productivity is also high. Sufficient ionic conductivity can be provided.

  Further, if the aperture ratio is too low, ion conductivity may be hindered. On the other hand, if the aperture ratio is too high, the obtained solid polymer electrolyte membrane cannot be sufficiently reinforced, and its strength may be insufficient. For this reason, it is preferable that an aperture ratio is 30 to 80%.

  Furthermore, the present invention relates to a solid polymer electrolyte membrane, and has a third region at the boundary between the first region and the second region, and in the third region, the first region and the second region The aperture ratio due to the through hole gradually decreases as the region 2 is reached.

  As a result, like the first aspect, the mechanical strength and dimensional stability of the solid polymer electrolyte membrane can be improved.

  Furthermore, the present invention relates to a solid polymer electrolyte membrane. In the third region, an average area per one of the through holes gradually decreases from the first region to the second region. Or the number of the through holes per unit area is gradually reduced.

  As a result, like the first aspect, the mechanical strength and dimensional stability of the solid polymer electrolyte membrane can be improved.

  Furthermore, the present invention is a membrane electrode assembly for a fuel cell having a solid polymer electrolyte membrane, comprising a catalyst layer containing a catalyst on both sides of the solid polymer electrolyte membrane, wherein the catalyst layer is the elastic body. It is arranged inside the enclosed area.

Thereby, the membrane electrode assembly for a fuel cell having the above-described solid polymer electrolyte membrane can improve the mechanical strength and the dimensional stability as a whole.
Therefore, the fuel cell having such a membrane electrode assembly can improve the reliability of the fuel cell because the mechanical strength and dimensional stability of the membrane electrode assembly are improved.

  Furthermore, the present invention relates to a membrane electrode assembly, wherein a gas diffusion layer is provided on at least one outer surface of the catalyst layer, and an outer edge portion of the gas diffusion layer is on the outer peripheral side of the first region in the solid polymer electrolyte membrane. It is characterized by being arranged in.

  Since the outer edge portion of the gas diffusion layer is arranged on the outer peripheral side of the first region, the corner portion of the gas diffusion layer is the second region where the tear strength and tensile strength are improved in the solid polymer electrolyte membrane, etc. Comes to abut. Therefore, it is possible to prevent the solid polymer electrolyte membrane and the like from being broken due to the stress concentration from the corners of the gas diffusion layer.

As described above, according to the present invention, the solid polymer electrolyte membrane includes a porous sheet in which through holes are filled with an ion exchange resin, and the porous sheet has no through holes or is opened by the through holes. The ratio is lower than the aperture ratio in the first region, and the second region located at the outer periphery of the first region is provided, so that the mechanical strength and dimensional stability of the solid polymer electrolyte membrane are improved. Can do.
In addition, since the elastic body is disposed so as to surround at least the first region in the second region on at least one side of the solid polymer electrolyte membrane, the elastic body is hardly displaced, and gas leakage associated therewith is prevented. be able to. Therefore, manufacturing cost can be reduced and productivity in mass production can be improved.

Hereinafter, embodiments of the present invention will be described.
A cross-sectional view of a unit cell for a fuel cell according to an embodiment of the present invention is shown in FIG.
In FIG. 1, a unit cell 100 for a fuel cell has a solid polymer electrolyte membrane 111. The solid polymer electrolyte membrane 111 has one porous sheet 113 (not shown in FIG. 1 for simplicity) for reinforcing the solid polymer electrolyte membrane 111 itself. The solid polymer electrolyte membrane 111 may have a plurality of porous sheets 113, and in this case, these are laminated and configured.

FIG. 2 is a plan view of the porous sheet 113, and FIG. 3 is an enlarged cross-sectional view taken along line AA in FIG. 2 when a filling portion 114 and a resin layer 125 described later are formed on the porous sheet 113.
2 and 3, the porous sheet 113 is based on a rectangular porous film 115 in which a large number of micropores (not shown) are formed. The material of the porous film 115 is not particularly limited as long as it is in the form of a film, but it is assumed that it has chemical stability, such as polytetrafluoroethylene, fluoroethylene-propylene copolymer, tetrafluoroethylene-perfluoroalkoxyethylene. It is preferably made of a copolymer, tetrafluoroethylene-ethylene copolymer, polysulfone, polyphenylene sulfide, polyarylate, polyether sulfone, polyether ether ketone, polyether imide, polyether amide, polypropylene or polyethylene. In addition, when it is desired to increase the mechanical strength rather than the chemical stability of the porous film 115, it is also preferable to use a metal foil such as stainless steel or titanium. In particular, since a through-hole 117 to be described later is formed in the porous film 115, it can be easily processed so that it can be easily punched, drilled, or laser processed. A material that can be perforated by is preferred.

  The porous film 115 is formed with a plurality of through holes 117 penetrating between the main surfaces 115 a substantially in parallel with the thickness direction so as to constitute the porous sheet 113. At this time, the through holes 117 are formed in a concentrated manner in a region including the central portion 115b of the porous film 115 and not including the outer edge portion 115c (hereinafter referred to as the central region 121). On the other hand, in the region closer to the outer edge 115c than the central region 121 (hereinafter referred to as the peripheral region 122), the through hole 117 is not formed at all (that is, the opening ratio of the through hole 117 is zero), or the through hole 117 Even if is formed, the aperture ratio is lower than that of the central region 121. In the boundary region between the central region 121 and the peripheral region 122 (hereinafter referred to as the boundary region 123), the aperture ratio due to the through-hole 117 gradually decreases from the central region 121 to the peripheral region 122. A through hole 117 is formed. For example, in FIG. 2, in the boundary region 123, the through holes 117 are formed so that the average area per one through hole 117 is reduced while maintaining the number of through holes 117 per unit area.

In addition, as shown in FIG. 4 (enlarged view of the boundary region 123), the number of through holes 117 per unit area is maintained in the boundary region 123 while maintaining the average area per one through hole 117. The through holes 117 may be formed so as to reduce the number, and although not shown, a method of reducing the average area per through hole 117 and a method of reducing the number of through holes 117 per unit area are combined. (Hereinafter, each description will be given by taking the porous sheet 113 having the configuration of FIG. 2 as an example, but the same applies to the porous sheet 113 having the configuration of FIG. 4 unless otherwise specified).
In each figure, a boundary line 124A is shown at the boundary between the central region 121 and the boundary region 123, and a boundary line 124B is shown at the boundary between the boundary region 123 and the peripheral region 122. It is a virtual line and does not exist (the same applies to the following).

And in such a porous sheet 113, it is preferable that the average area per one through-hole 117 in the center area | region 121 is about 1 * 10 < ^-3 > -20mm < ² >, Especially 4 * 10 < ^-3 > -4mm < ² >. It is preferable that it is a grade. For example, if the average area per one through-hole 117 is too small, the number of through-holes 117 per unit area will be very large if the aperture ratio is maintained in a certain range as follows. May be low, or it may be difficult to fill the ion exchange resin. On the other hand, if the average area per through-hole 117 is too large, the obtained solid polymer electrolyte membrane 111 cannot be reinforced uniformly, and as a result, the strength thereof may be insufficient. Therefore, if the average area per through hole 117 is about 1 × 10 ^{−3 to} 20 mm ² , the solid polymer electrolyte membrane 111 can be given a practically uniform and sufficient strength, and the productivity can be increased. And high ion conductivity can be provided.

Moreover, it is preferable that the aperture ratio in the center area | region 121 of the porous sheet 113 in which such the through-hole 117 was formed is 30 to 80%.
When the solid polymer electrolyte membrane 111 having the porous sheet 113 is applied to a solid polymer fuel cell using hydrogen or a fuel gas containing hydrogen as a fuel, the aperture ratio is 50 to 75%. It is particularly preferred. For example, if the aperture ratio is too low, ion conductivity may be hindered. On the other hand, if the aperture ratio is too high, the obtained solid polymer electrolyte membrane 111 cannot be sufficiently reinforced, and its strength may be insufficient.

  In addition, when the solid polymer electrolyte membrane 111 having the porous sheet 113 is applied to a direct methanol fuel cell using methanol or an aqueous solution thereof as a fuel, the aperture ratio is particularly 40 to 75%. preferable. For example, if the aperture ratio is too low, ion conductivity may be hindered. On the other hand, if the aperture ratio is too high, the obtained solid polymer electrolyte membrane 111 cannot be sufficiently reinforced, the strength thereof may be insufficient, and the permeation amount of methanol may increase. is there.

  In addition, the size and shape of the through holes 117 may all be uniform, but holes having two or more sizes and shapes may be mixed. Further, the shape of the through-hole 117 is not particularly limited. However, if there is a corner, it may be cut off and the strength as a reinforcing body may be reduced.

  In forming the through hole 117, there are a method of mechanically punching the porous film 115, a method of forming the through hole 117 with respect to the porous film 115 using a laser beam, and the like. For example, in the method of mechanically punching the porous film 115, several tens to thousands of porous films 115 are stacked, and a punching die that can form hundreds to tens of thousands of through holes 117 at a time is used. It becomes possible to process a large number of through holes 117 in a short time. In addition, drilling is also suitable, and dozens or thousands of porous membranes 115 are stacked, and a large number of through holes 117 are processed in a short time by drilling them using a multi-axis NC drill machine. Can be produced at low cost.

  The thickness of the porous sheet 113 is preferably 3 to 50 μm, particularly 5 to 30 μm, when the solid polymer electrolyte membrane 111 having the porous sheet 113 is applied to a solid polymer fuel cell. Preferably there is. For example, if the porous sheet 113 is too thin, the resulting solid polymer electrolyte membrane 111 may not be sufficiently reinforced. On the other hand, if the porous sheet 113 is too thick, the resulting solid polymer electrolyte membrane 111 is too thick, and there is a possibility that the ion conduction resistance becomes high and the resistance loss becomes large and sufficient performance cannot be obtained. .

  Further, when the solid polymer electrolyte membrane 111 having the porous sheet 113 is applied directly to a methanol fuel cell, the thickness of the porous sheet 113 is preferably 20 to 200 μm, particularly 30 to 100 μm. Is preferred. For example, if the porous sheet 113 is too thin, the solid polymer electrolyte membrane 111 may not be sufficiently reinforced due to the influence of swelling of the solid polymer electrolyte membrane 111 by methanol or the like. On the other hand, if the porous sheet 113 is too thick, the solid polymer electrolyte membrane 111 is too thick, and the ion conduction resistance becomes high and the resistance loss becomes large, so that there is a possibility that sufficient performance cannot be obtained.

  And although it does not specifically limit, In order to be able to reinforce the obtained solid polymer electrolyte membrane 111 uniformly, it is desirable that the film thickness of the porous sheet 113 is uniform.

  Furthermore, manifold holes 119 and 120 are formed in the peripheral region 122 of the porous sheet 113. The manifold holes 119, 120 have three independent holes 119a, 119b, 119c and holes 120a, 120b, 120c each having a substantially rectangular cross section, and the holes 119a, 119b, 119c and 120 a, 120 b, 120 c are arranged in parallel with both short sides of the porous sheet 113. In the manifold holes 119 and 120, a membrane catalyst layer assembly 131 (described later) using, for example, a solid polymer electrolyte membrane 111 is stacked with a gasket 150 disposed between them to form a stack. At this time, a flow path for the fuel, the oxidant, and the refrigerant is provided. For example, fuel gas flows through the manifold holes 120c and 119c, oxidant gas flows through the manifold holes 120a and 119a, and refrigerant flows through the manifold holes 120b and 119b.

And the through-hole 117 of such a porous sheet 113 is filled with an ion exchange resin, whereby a filling portion 114 is formed in the porous sheet 113. The filling portion 114 is not limited to being formed only in the through-hole 117, and may be thinly present in the surface layer portion of the porous sheet 113 (not shown).
Here, as the ion exchange resin constituting the filling portion 114, a cation exchange resin made of a perfluorocarbon polymer having a sulfonic acid group is preferable, but if it is a cation exchange resin, a hydrocarbon polymer or a partial fluorine is used. It is also possible to use a cation exchange resin made of a hydrocarbon-based polymer. The ion exchange resin may be a single ion mixture or a mixture of two or more ion exchange resins. Since the filling portion 114 is reinforced by the porous sheet 113, the strength of the filling portion 114 itself may not be so high. Therefore, it is preferable to use an ion exchange resin having a high ion exchange capacity even if it is not high in strength to increase the conductivity of the obtained solid polymer electrolyte membrane 111 as the ion exchange resin constituting the filling portion 114.

  The method for filling the porous sheet 113 with the ion exchange resin is not particularly limited. For example, the porous sheet 113 is cast from a liquid (hereinafter referred to as an ion exchange resin-containing liquid) in which the ion exchange resin is dispersed (dissolved) in a dispersion medium (solvent). A method of thermocompression-bonding a cast film formed by a method or the like to both outer surfaces of the porous sheet 113, a method of coating an ion exchange resin-containing liquid on one or both outer surfaces of the porous sheet 113, There is a method of impregnating the sheet 113 and drying.

  Further, such a porous sheet 113 may remain in a state where the filling portion 114 is formed, but in order to improve the conductivity of the solid polymer electrolyte membrane 111, the porous sheet 113 is further provided on at least one side, preferably both sides. A resin layer 125 made only of an ion exchange resin may be formed (FIG. 3 shows the resin layer 125 formed on both outer surfaces of the porous sheet 113).

  In this case, the ion exchange resin constituting the resin layer 125 may be the same material as the ion exchange resin constituting the filling portion 114, but may be a different material. When using a different material, the strength of the resin layer 125 itself is increased by using, for example, an ion exchange resin having higher strength than the ion exchange resin constituting the filling portion 114 even if the ion exchange capacity is lower. Can do.

  Further, when the resin layer 125 is formed, the resin layer 125 is larger than the area of the central region 121 so as to cover the entire central region 121 of the porous sheet 113 and does not include the outer edge portion 115c. It is designed to be smaller than the area. However, the present invention is not limited to this, and as shown in FIG. 5, a resin layer 125 may be formed on both outer surfaces of the porous sheet 113 so as to cover the entire region of the main surface 115 a (hereinafter, as shown in FIG. 3). In the following description, the case where the resin layer 125 is formed will be described as an example, but the case where the resin layer 125 is formed as shown in FIG. 5 is the same unless otherwise specified).

  In forming the resin layer 125, the resin layer 125 may be formed by coating when the filling portion 114 is formed on the porous sheet 113. Alternatively, the resin layer 125 may be separately prepared and the porous sheet 113 may be formed by hot pressing or the like. You may join on top. Moreover, you may be comprised with both the resin layer 125 formed by coating, and the resin layer 125 produced separately. Furthermore, a resin layer 125 may be formed by applying an ion exchange resin-containing liquid on the porous sheet 113. Alternatively, a layer made of resin may be separately prepared by a casting method or the like, and this layer may be formed as the porous sheet 113. The filling portion 114 and the resin layer 125 may be formed simultaneously by placing them on both sides of the substrate and hot pressing. Further, the resin layer 125 may be formed by repeatedly performing these methods or combining them.

  And the porous sheet 113 in which the filling part 114 and the resin layer 125 were formed as mentioned above comprises the solid polymer electrolyte membrane 111 shown in FIG. As described above, when the solid polymer electrolyte membrane 111 has a plurality of porous sheets 113, the porous sheets 113 made of different polymers may be laminated. In this case, there may be a surface in which the resin layer 125 is not formed between the adjacent porous sheets 113, or a surface in which the resin layers 125 are in contact with each other. .

  Furthermore, catalyst layers 127 and 128 are joined to both outer surfaces 111a of the solid polymer electrolyte membrane 111, respectively, so that a membrane catalyst layer assembly 131 is formed. FIG. 6 shows a configuration diagram of this membrane catalyst layer assembly. 6A is a plan view of the membrane-catalyst layer assembly, and FIG. 6B is an enlarged cross-sectional view taken along line BB in FIG. 6A.

In FIG. 6, the catalyst layers 127 and 128 joined to the solid polymer electrolyte membrane 111 include the central region 121 so as to overlap with the central region 121 of the porous sheet 113 constituting the solid polymer electrolyte membrane 111. It is formed as follows. In FIG. 6, the dotted lines indicate the boundary lines 124 </ b> A and 124 </ b> B of each region. In FIG. 6, the catalyst layers 127 and 128 include the central region 121. The region up to the boundary line 124B is shown to be included. However, in this case, the present invention is not limited to this as long as it includes the central region 121, and may include, for example, a region up to the boundary line 124A.
On the other hand, a portion where the catalyst layers 127 and 128 are not joined is left in the peripheral region 122 of the solid polymer electrolyte membrane 111. The catalyst layers 127 and 128 usually include a catalyst in which platinum or a platinum alloy is supported on carbon, and preferably further includes an ion exchange resin. The ion exchange resin here may be the same material as the ion exchange resin constituting the filling portion 114 or the resin layer 125 formed in the porous sheet 113, but may be a different material.

  Further, a gasket 150 (corresponding to an elastic body) is attached to a portion where the catalyst layers 127 and 128 are not joined on both outer surfaces 111a of the solid polymer electrolyte membrane 111 so as to cover the entire surface of the portion. . However, in the gasket 150, when the manifold holes 119 and 120 are formed in the solid polymer electrolyte membrane 111, the manifold holes 151 and 152 are opened in the portions overlapping with those portions. As a result, on both outer surfaces 111a of the solid polymer electrolyte membrane 111, the periphery of the portion where the catalyst layers 127, 128 are formed, and the holes 119a, 119b, 119c and the holes 120a, 120b, 120c of the manifold holes 119, 120, respectively. The gasket 150 is disposed around the portion where the is formed.

  At this time, as a method of attaching the gasket 150 to the solid polymer electrolyte membrane 111, a sealant made of silicon-based elastomer, fluorine-based elastomer or the like may be applied and cured by a dispenser or the like according to the above shape. Alternatively, a sealing agent may be injection molded around the membrane catalyst layer assembly 131 using a mold. The resin used for injection molding is preferably a fluorine-based resin, polypropylene, polyphenylene sulfide, or an alloy containing these, but may be other resins.

  Furthermore, as shown in FIG. 1, gas diffusion layers 133 and 134 are provided on both outer surfaces 131a on the catalyst layers 127 and 128 side of the membrane catalyst layer assembly 131 formed as described above. The gas diffusion layers 133 and 134 have a size that just covers the catalyst layers 127 and 128. When the catalyst layers 127 and 128 are formed so as to include the central region 121, the gas diffusion layers 133 are formed. , 134 are arranged closer to the outer edge than the center region 121 (that is, closer to the outer edge than the boundary line 124A between the center region 121 and the boundary region 123). The gas diffusion layers 133 and 134 are usually made of a conductive porous material such as carbon cloth or carbon paper, and function as a current collector or have a gas that is substantially uniform with respect to the membrane catalyst layer assembly 131. It has a function of diffusing gas so that it can be supplied.

  The membrane / catalyst layer assembly 131, the gasket 150, and the gas diffusion layers 133 and 134 constitute a membrane / electrode assembly 137 with a gasket.

Furthermore, gas flow paths 147 and 148 are formed between the separators 141 and 142 on both outer surfaces 137a on the gas diffusion layers 133 and 134 side of the membrane electrode assembly 137 with gasket. At this time, the separators 141 and 142 have a size that covers the entire surface of the solid polymer electrolyte membrane 111, and concave grooves 145 and 146 are respectively engraved in portions facing the catalyst layers 127 and 128. ing. The grooves 145 and 146 form gas flow paths 147 and 148 when the separators 141 and 142 and the membrane electrode assembly 137 are tightened. At this time, the gas flow paths 147 and 148 communicate with the manifold holes 119 and 120 of the solid polymer electrolyte membrane 111 at the ends thereof.
Further, the gaskets 150 attached to the above-described solid polymer electrolyte membrane 111 are interposed in portions of the separators 141 and 142 that do not face the catalyst layers 127 and 128, and the gas flow paths 147, 148 and the like are sealed from the outside.

  As described above, the single cell 100 which is the minimum unit of power generation of the fuel cell is configured. When this single cell 100 is used in a fuel cell, a plurality of single cells 100 are stacked and used in order to generate a practical voltage.

In such a configuration, hydrogen is supplied to the anode side of the unit cell 100. On the other hand, oxygen or air is supplied to the cathode side. At this time, supply of hydrogen, oxygen, and air is performed via the manifold holes 119 and 120 and the gas flow paths 147 and 148 of the solid polymer electrolyte membrane 111. As a result, a reaction of H ₂ → 2H ⁺ + 2e ⁻ occurs on the anode side. On the other hand, the reaction of 1 / 2O ₂ + 2H ⁺ + 2e ⁻ → H ₂ O occurs on the cathode side. Therefore, chemical energy is converted into electrical energy.

At this time, the solid polymer electrolyte membrane 111 has a porous sheet 113 in which the through holes 117 are filled with an ion exchange resin. Therefore, the solid polymer electrolyte membrane 111 is reinforced by the porous sheet 113. Therefore, the mechanical strength and dimensional stability of the solid polymer electrolyte membrane 111 can be improved.
In addition, in the peripheral region 122 of the porous sheet 113, the opening ratio of the through holes 117 is lower than that of the central region 121. Therefore, the tear strength and tensile strength in the peripheral region 122 can be improved, and the mechanical strength of the solid polymer electrolyte membrane 111 can be improved. Further, since the manifold holes 119 and 120 are formed in the peripheral region 122, the manifold holes 119 and 120 can prevent the strength of the solid polymer electrolyte membrane 111 from being lowered.

  Furthermore, in the single cell 100 of the present invention, the outer edge parts 133 a and 134 a of the gas diffusion layers 133 and 134 are arranged on the outer edge part side of the center region 121. Therefore, the corners of the outer edge portions 133a and 134a of the gas diffusion layers 133 and 134 come into contact with the peripheral region 122 of the solid polymer electrolyte membrane 111 having improved tear strength and tensile strength. Accordingly, it is possible to prevent the solid polymer electrolyte membrane 111 from being broken due to stress concentration from the corners of the outer edge portions 133a and 134a.

  In the unit cell 100 of the present invention, the entire surface of the outer surface 111a of the solid polymer electrolyte membrane 111 where the catalyst layers 127 and 128 are not joined (except for the portion where the manifold holes 119 and 120 are formed). The gasket 150 is attached to the periphery of the portion where the catalyst layers 127, 128 are formed, and the portions where the holes 119a, 119b, 119c and the holes 120a, 120b, 120c of the manifold holes 119, 120 are formed. A gasket 150 is arranged around the periphery. Therefore, the gasket 150 can seal the gas flow paths 147 and 148 and the manifold holes 119 and 120 to the outside.

Further, the gasket 150 is formed using a method such as coating, molding, injection molding, or the like, and is integrated with the solid polymer electrolyte membrane 111. Therefore, it is difficult for the gasket 150 to be displaced, and gas leakage and the like associated therewith can be prevented. Therefore, the manufacturing cost of the single cell 100 can be reduced, and the productivity at the time of mass production can be improved.
In addition, since the gasket 150 can be formed using a method such as coating, molding, injection molding, or the like, the gasket 150 can be easily attached to the solid polymer electrolyte membrane 111. Therefore, there is no need to perform a step of arranging a frame-like reinforcing film or the like in the peripheral region of the membrane electrode assembly 137 as in Patent Document 3, so this step can be omitted and the manufacturing cost of the unit cell 100 can be reduced. Thus, productivity at the time of mass production can be improved.

  Furthermore, since the unit cell 100 of the present invention has different opening ratios due to the through holes 117 in the central region 121 and the peripheral region 122, it does not require a function as the solid polymer electrolyte membrane 111 on the outer edge 115c side. In this case, the manufacturing cost can be reduced by the amount that the through hole 117 is not formed in the peripheral region 122. In addition, when the resin layer 125 is formed on the porous sheet 113, the peripheral region 122 has a portion where the resin layer 125 is not formed. Therefore, the amount of the resin layer 125 used can be reduced by that amount, and the manufacturing cost can be reduced. Can be reduced.

  The unit cell 100 of the present invention can be suitably used in either a direct methanol fuel cell in which methanol is supplied to the anode side or a membrane humidifier.

  Further, in the present invention, as shown in FIG. 6, the gasket 150 has been described as being attached to the entire surface of the outer surface 111a of the solid polymer electrolyte membrane 111 where the catalyst layers 127 and 128 are not joined. Not limited to. For example, as shown in FIG. 7, the gasket 160 may be attached only to a part thereof. 7A is a plan view of the membrane-catalyst layer assembly, and FIG. 7B is an enlarged sectional view taken along the line CC in FIG. 7A.

  In this case, the gasket 160 includes an elastic ring 161 formed so as to surround portions where the catalyst layers 127 and 128 are formed on both outer surfaces 111a of the solid polymer electrolyte membrane 111, and holes 119a included in the manifold holes 119 and 120. 119b, 119c and elastic rings 162, 163, 164, 165, 166, 167 formed so as to surround each of the holes 120a, 120b, 120c, and these are integrated. The rings 161,..., 167 have a semi-elliptical cross section, and their string portions are in contact with the solid polymer electrolyte membrane 111. In addition, the rings 161,..., 167 are attached at substantially the same position on both outer surfaces 111 a of the solid polymer electrolyte membrane 111.

  Accordingly, even if the gasket 150 is not provided on the entire surface of the solid polymer electrolyte membrane 111 where the catalyst layers 127 and 128 are not joined on both outer surfaces 111a, the periphery of the portion where the catalyst layers 127 and 128 are formed, and Since the gasket 160 is arranged around the portion of the manifold holes 119, 120 where the holes 119a, 119b, 119c and the holes 120a, 120b, 120c are formed, like the gasket 150 described above, The gas flow paths 147 and 148 and the manifold holes 119 and 120 can be sealed to the outside. Therefore, the material cost required for the gasket 160 can be reduced.

  Next, the effect of the present invention will be described by quantitatively quantifying.

(Example 1)
(Membrane preparation)
A polyphenylene sulfide film (trade name: Torelina 3030-12, manufactured by Toray Industries, Inc.) with a thickness of 12 μm and a 100 mm square, centered on a φ500 μm through-hole 117 (average area per piece is about 0.196 mm ² ) by a multi-axis drill About 8700 holes are formed in a staggered arrangement so that the distance between them is 580 μm, and a central region 121 of about 5 cm square with an aperture ratio of about 68% is formed. Next, a through-hole 117 having a diameter of 400 μm is formed in the peripheral portion so as to surround the outer periphery with an interval of 580 μm between the centers, and the outer periphery is also surrounded with an interval of 580 μm between the centers. A through hole 117 having a diameter of 300 μm is formed in one row, and this portion is defined as a boundary region 123. As a result, a porous sheet 113 of about 100 mm square having a peripheral region 122 having no through hole 117 on the outer side of the boundary region 123 was produced.

Next, a repeating unit based on CF ₂ = CF ₂ on a polyethylene terephthalate base material (hereinafter referred to as a PET base material) having a thickness of about 100 μm whose surface has been treated with a silicone release agent. Of ion exchange resin consisting of repeating units based on CF ₂ ═CF—OCF ₂ CF (CF ₃ ) —OCF ₂ CF ₂ SO ₃ H (ion exchange capacity: 1.1 meq / g dry resin, commercial product Name: Flemion, manufactured by Asahi Glass Co., Ltd., hereinafter referred to as “dispersion a”) was applied by a die coating method so that the total thickness was 15 μm, and then dried at 80 ° C. Then, two of these were manufactured, the side on which the dispersion liquid a was applied was put on the porous sheet 113 side and sandwiched, and hot-pressed at 150 ° C. for 20 minutes to obtain a porous sheet reinforcing film (hereinafter this film was Called membrane A1).

(Electrode bonding)
Furthermore, catalyst layers 127 and 128 were produced as follows. First, the dispersion a and a supported catalyst in which 55% by mass of platinum was supported on carbon were dispersed in a mixed dispersion medium (1: 1 by mass) of ethanol and water, and the resulting solid content concentration was 14%. % Catalyst dispersion was coated on a 100 μm-thick PET film whose surface was treated with a silicone release agent by a die coating method, dried at 80 ° C. and 10 μm in thickness, and the platinum loading was about 0.4 mg / cm ² catalyst layers 127 and 128 were formed. Next, catalyst layers 127 and 128 cut into 5 cm squares were respectively arranged on both outer surfaces of the membrane A1, and the catalyst layers 127 and 128 were transferred to the membrane A1 by a transfer method to produce a membrane catalyst layer assembly 131. . This transfer was performed at a temperature of 130 ° C. and a pressure of 3 MPa. Then, the catalyst layer 127, 128 of 25 cm ² is arranged at the center portion of the membrane-catalyst layer assembly 131, and the outer shape is punched with a Thomson type to obtain a 6 cm × 6 cm outer shape (hereinafter referred to as this Membrane catalyst layer assembly 131 is referred to as assembly B2.)

(Installation of gasket)
Then, the bonded body B2 obtained as described above is brought into contact with the mold, and injection molding is performed using a polypropylene resin as a sealant, so that, for example, as shown in FIG. The catalyst layers 127 and 128 can be formed so as to cover the entire surface where the catalyst layers 127 and 128 are not joined. At this time, the gasket 150 is formed on each surface of the bonded body B2 so as to have a thickness of 1.5 mm (hereinafter, the membrane-catalyst layer bonded body 131 with the gasket is referred to as a bonded body B3).

(Gas leak test and battery test)
Next, the joined body B3 is placed between a pair of separators 141, 142 having gas flow paths 147, 148 for supplying a reaction gas, and a conductive layer having a thickness of about 10 μm made of carbon black and polytetrafluoroethylene particles. Is sandwiched between a current collector plate and an end plate together with gas diffusion layers 133 and 134 having a carbon cloth having a thickness of about 300 μm as a base material and a fuel having an effective electrode area for measuring cell performance of 25 cm ² A single cell 100 for a battery is obtained.

  And in the state which supplied the nitrogen gas of pressure 30kPa to the anode side of this single cell 100, the presence or absence of gas leak can be confirmed by putting in water and observing the presence or absence of bubble generation for 5 minutes. Next, the presence or absence of gas leak can be confirmed by performing the same test on the cathode side. As a result, no bubbles are observed from any of them, and it can be confirmed that no gas leak occurs.

  Further, the cell temperature is set to 70 ° C., and hydrogen gas is supplied to the anode side and air is supplied to the cathode side of the battery. The supplied gas has a hydrogen gas utilization rate of 70% and an air utilization rate of 40%. Each gas is humidified through a bubbler set at 70 ° C. and then supplied to the fuel cell. Table 1 shows the relationship between the current density and the cell voltage.

(Example 2)
(Membrane preparation)
At the center of the main surface of a polyphenylene sulfide film (trade name: Torelina 3030-12, manufactured by Toray Industries, Inc.) with a thickness of 12 μm and 100 mm square, through holes 117 (average area per piece is about 0.196 mm by a multi-axis drill) ² ) about 8700 holes in a staggered arrangement so that the center-to-center distance is 580 μm, and an about 5 cm square center region 121 having an aperture ratio of about 68% and a peripheral region 122 on the periphery thereof. A 100 mm square porous sheet 113 was produced. The peripheral region 122 is not open.

  And this porous sheet 113 is arrange | positioned on the PET base material of about 100 micrometers in thickness which processed the surface by the silicone type mold release agent, and the total thickness becomes 22 micrometers by the die-coating method on the dispersion liquid a mentioned above on this. And then dried at 80 ° C. The obtained membrane is formed by laminating a 12 μm thick porous sheet 113 in which through-holes 117 are filled with an ion exchange resin and a 10 μm thick resin layer 125 that is not reinforced on one outer surface of the porous sheet 113. It has become a film.

  Next, the PET base material was peeled from the film, the front and back sides were reversed, and the surface that was not in contact with the base material was in contact with the base material, and was again placed on a separately prepared PET base material. Then, the dispersion liquid a was coated thereon by a die coating method so that the total thickness became 32 μm, and then dried at 80 ° C. Thereafter, the obtained film was heat-treated at 120 ° C. for 30 minutes, and the PET substrate was peeled off to obtain a film (hereinafter, this film is referred to as “film C1”). The membrane C1 has a configuration in which a porous sheet 113 having a thickness of 12 μm in which through-holes 117 are filled with an ion exchange resin and a resin layer 125 having a thickness of 10 μm that is not reinforced are laminated on both outer surfaces of the porous sheet 113. doing.

(Electrode bonding, gasket mounting)
Then, the catalyst layers 127 and 128 having a platinum loading of about 0.4 mg / cm ² are formed on the membrane C1 in the same manner as in Example 1, and this is transferred to the membrane C1 by a transfer method. A catalyst layer assembly 131 was prepared to have an outer shape of 6 cm × 6 cm (hereinafter, this membrane catalyst layer assembly 131 is referred to as a assembly D2). The joined body D2 has a center region 121 of 5 cm square at the center.

  Further, when the same method as in Example 1 is applied to the joined body D2, a membrane-catalyst layer joined body 131 with a gasket is obtained (hereinafter, the membrane-catalyst layer joined body 131 is referred to as a joined body D3).

(Gas leak test and battery test)
When the presence or absence of gas leak is confirmed with respect to the unit cell 100 using the joined body D3 by the same method as in Example 1, no gas is observed from either the anode side or the cathode side, and gas leak occurs. It can be confirmed that they are not.
Furthermore, when the battery test is performed in the same manner as in Example 1, the relationship between the current density and the cell voltage as shown in Table 1 is obtained.

(Example 3)
(Membrane preparation)
On a polyphenylene sulfide film (trade name: Torelina 3030-12, manufactured by Toray Industries, Inc.) having a thickness of 50 μm and a 100 mm square, through holes 117 (average area per piece is about 0.071 mm ² ) of φ300 μm by a multi-axis drill, A porous sheet 113 of about 25 mm square having about 6525 holes opened in a staggered arrangement so that the center-to-center distance was 405 μm was produced. The aperture ratio of the porous sheet 113 is 50%.
Next, a porous sheet reinforcing membrane was obtained in the same manner as in the production method of the membrane A1 in Example 1 except that this porous sheet 113 was used (hereinafter, this membrane is referred to as membrane E1).

(Electrode bonding, gasket mounting)
Furthermore, catalyst layers 127 and 128 were produced as follows. First, the dispersion a and a supported catalyst in which 55% by mass of platinum was supported on carbon were dispersed in a mixed dispersion medium (1: 1 by mass) of ethanol and water, and the resulting solid content concentration was 14%. % Catalyst dispersion was coated on a 100 μm-thick PET film whose surface was treated with a silicone release agent by a die coating method, dried at 80 ° C., 20 μm thick, and a platinum loading of about 1 mg / cm ^2. Catalyst layer 127 was formed. Next, the dispersion liquid a and a supported catalyst in which an alloy of platinum and ruthenium was supported by 50 mass% on carbon were dispersed in a mixed dispersion medium (mass ratio of 1: 1) of ethanol and water to obtain. A catalyst dispersion having a solid content of 14% by mass is coated on a 100 μm-thick PET film whose surface is treated with a silicone-based mold release agent by a die coating method, dried at 80 ° C. and 20 μm in thickness, with a platinum carrying amount. About 1 mg / cm ² of the catalyst layer 128 was formed. Then, the two types of catalyst layers 127 and 128 cut into 5 cm squares are arranged one by one on both outer surfaces of the membrane E1, and the catalyst layers 127 and 128 are transferred to the membrane E1 by a transfer method, so that the membrane catalyst layer bonding is performed. A body 131 was produced. This transfer was performed at a temperature of 130 ° C. and a pressure of 3 MPa. Then, with respect to this membrane-catalyst layer assembly 131, each of the 25 cm ² catalyst layers 127 and 128 is arranged at the center of both outer surfaces 131a, and the outer shape is punched out in a Thomson shape, and the outer shape of 110 mm × 90 mm. (Hereinafter, this membrane catalyst layer assembly 131 will be referred to as assembly F2).

  Further, the gasket 150 is attached to the joined body F2 as follows. First, the joined body F2 is sucked and placed on an aluminum suction table, and a sealant (sealant TB1153 manufactured by Three Bond Co.) is used in FIG. 6 using an XY robot (Musashi Engineering) and a dispenser. As shown, it is applied to one outer surface of the joined body F2 so as to cover the entire surface of the joined body F2 where the catalyst layers 127, 128 are not joined. Further, the gasket 150 is attached by curing the sealant in an electric furnace at 100 ° C. for 30 minutes after application. Similarly, the gasket 150 is attached to the opposite surface of the joined body F2 by applying a sealant and drying it in an electric furnace (hereinafter, the membrane-catalyst layer joined body 131 with the gasket is referred to as a joined body F3).

(Gas leak test and battery test)
When the presence or absence of gas leak is confirmed for the unit cell 100 using the joined body F3 by the same method as in Example 1, no gas bubbles are observed from either the anode side or the cathode side, and gas leak occurs. It is confirmed that they are not.
Further, when the cell temperature is set to 80 ° C., 15 cc of a 10 wt% methanol aqueous solution is supplied to the anode side of the battery per minute and the air utilization rate is supplied to 30% of the cathode side, the current density as shown in Table 1 is obtained. And the cell voltage relationship.

Example 4
Six joined bodies B3 are produced in the same manner as in Example 1, and sandwiched together with gas diffusion layers 133 and 134 between a pair of separators 141 and 142 each having a gas flow path 147 and 148 for supplying a reactive gas. 6 sets are prepared, a total of 5 cooling plates each having a flow path for supplying cooling water are sandwiched between them, and a current collecting plate is arranged on the outside, and the outside is tightened with an end plate, A 6-cell stack with an area of 25 cm ² is completed. When this 6-cell stack is subjected to a gas leak test in the same manner as the unit cell 100 of Example 1, no bubbles are observed from any of the 6-cell stacks, confirming that no gas leak has occurred.

  Further, when 70 ° C. hot water is circulated from the end plate to the cooling plate in this 6-cell stack, hydrogen gas is supplied to the anode side at a utilization rate of 70%, and air is supplied to the cathode side at a utilization rate of 40%. The result as shown is obtained.

(Comparative Example 1)
CF ₂ = repeating unit _{CF 2 = CF-OCF 2 CF} (CF 3) based on CF ₂ -OCF ₂ CF ₂ SO ₃ ion exchange membrane having a thickness of 30μm consisting of repeating units based on H (ion exchange capacity: 1 .1 milliequivalent / gram dry resin, trade name: Flemion SH-30, manufactured by Asahi Glass Co., Ltd.) was used as the membrane (hereinafter this membrane is referred to as membrane G1).

(Electrode bonding)
Then, the catalyst layers 127 and 128 having a platinum loading of about 0.4 mg / cm ² are formed on the film G1 in the same manner as in Example 1, and this is transferred to the film G1 by a transfer method. A catalyst layer assembly 131 was produced. The outer shape of the membrane catalyst layer assembly 131 was a rectangle of 110 mm × 90 mm (hereinafter, this membrane catalyst layer assembly 131 is referred to as an assembly H2). In the bonded body H2, many wrinkles were generated around the film.

(Gas leak test and battery test)
Next, the joined body H2 is placed between a pair of separators 141 and 142 having gas flow paths 147 and 148 for supplying a reaction gas, and a conductive layer having a thickness of about 10 μm made of carbon black and polytetrafluoroethylene particles. Gas diffusion layers 133 and 134 made of carbon cloth with a thickness of about 300 μm formed on the surface and gaskets are arranged, and these are sandwiched between current collector plates and end plates, and are effective for battery performance measurement A unit cell 100 for a fuel cell having an electrode area of 25 cm ² was completed.
And the presence or absence of the gas leak was confirmed with the method similar to Example 1 with respect to the single cell 100 using the joined body H2. In this case, 5 to 10 bubbles were observed in 10 minutes from both the anode side and the cathode side, and it was confirmed that there was a gas leak.
Further, the cell temperature was set to 70 ° C., and hydrogen gas was supplied to the anode side and air was supplied to the cathode side of the battery. The supplied gas was supplied to the fuel cell after humidifying it through a bubbler set at 70 ° C. with a hydrogen gas utilization rate of 70% and an air utilization rate of 40%. Table 1 shows the relationship between the current density and the cell voltage.

(Comparative Example 2)
CF ₂ = repeating unit _{CF 2 = CF-OCF 2 CF} (CF 3) based on CF ₂ -OCF ₂ CF ₂ SO ₃ ion exchange membrane having a thickness of 50μm consisting of repeating units based on H (ion exchange capacity: 1 .1 milliequivalent / gram dry resin, trade name: Flemion SH-50, manufactured by Asahi Glass Co., Ltd.) was used as the membrane (hereinafter this membrane is referred to as membrane I1).

(Electrode bonding)
Then, the catalyst layers 127 and 128 were transferred to the membrane I1 by the transfer method in the same manner as in Example 3 to produce a membrane catalyst layer assembly 131. The outer shape of the membrane catalyst layer assembly 131 was a rectangle of 110 mm × 90 mm (hereinafter, this membrane catalyst layer assembly 131 will be referred to as the assembly J2). In the joined body J2, many wrinkles occurred around the film.

(Gas leak test and battery test)
Next, the joined body J2 is formed between a pair of separators 141 and 142 having gas flow paths 147 and 148 for supplying a reaction gas, and a conductive layer made of carbon black and polytetrafluoroethylene particles having a thickness of about 10 μm. Gas diffusion layers 133 and 134 having a carbon cloth with a thickness of about 300 μm as a base material and gaskets are disposed between the current collector plate and the end plate, and an effective electrode for measuring battery performance A unit cell 100 for a fuel cell having an area of 25 cm ² was completed.
And the presence or absence of the gas leak was confirmed with the method similar to Example 1 with respect to the single cell 100 using the joined body J2. Also in this case, 5 to 10 bubbles were observed for 10 minutes from both the anode side and the cathode side, and it was confirmed that there was a gas leak.
Further, the cell temperature was set to 80 ° C., 15 cc of a 10 wt% aqueous methanol solution was supplied to the anode side of the battery, and the air utilization rate was supplied to the cathode side at 30%. Table 1 shows the relationship between the current density and the cell voltage.

(Comparative Example 3)
Six bonded bodies H2 are produced in the same manner as in Comparative Example 1, and a 6-cell stack with an electrode area of 25 cm ² is obtained in the same manner as in Example 4 except that the bonded body H2 is used instead of the bonded body B3. When this 6-cell stack was subjected to a gas leak test in the same manner as the unit cell 100 of Example 1, 5 to 20 bubbles were observed from each cell for 10 minutes from both the anode side and the cathode side. It is confirmed that there are many occurrences.
Further, when this 6-cell stack is evaluated by supplying gas in the same manner as in Example 4, the results shown in Table 1 are obtained.

In Table 1, from the measurement results of the cell voltages of Examples 1 to 4 and Comparative Examples 1 to 3, the single cell 100 of the present invention has high performance by forming the through hole 117 as in the present invention. I understand that.
Further, as described above, from the results of the gas leak tests of Examples 1 to 4 and Comparative Examples 1 to 3, the solid polymer electrolyte membrane 111 has the porous sheet 113 in which the through holes 117 are filled with the ion exchange resin. Thus, it can be seen that the mechanical strength is increased and the generation of wrinkles is prevented.
As described above, the solid polymer electrolyte membrane 111 of the present invention can improve mechanical strength and dimensional stability. In addition, a fuel cell having this can exhibit high performance.

Sectional drawing of the unit cell for fuel cells which is embodiment of this invention Plan view of perforated sheet AA arrow enlarged sectional view in FIG. Another example of FIG. Another example of FIG. Configuration diagram of membrane catalyst layer assembly Another example of FIG. Sectional view of a conventional unit cell for a fuel cell

Explanation of symbols

1,100 Single cell
11, 111 Solid polymer electrolyte membrane
27, 28, 127, 128 Catalyst layer
31, 131 Membrane / catalyst layer assembly
33, 34, 133, 134 Gas diffusion layer
37, 137 Membrane electrode assembly
41, 42, 141, 142 Separator
47, 48, 147, 148 Gas flow path
53, 54, 150, 160 Gasket
113 perforated sheet
114 Filling part
115 porous membrane
117 Through-hole
119, 120, 151, 152 Manifold hole
121 Central area
122 Surrounding area
123 Boundary area
125 resin layer

Claims (8)

A porous sheet comprising a porous sheet having a plurality of through holes and an ion exchange resin filled in the through holes, and the porous sheet has a first region and the through holes are not formed; An aperture ratio due to the through hole is lower than an aperture ratio in the first area, and a second area located on an outer peripheral portion of the first area, and at least in the second area on one side, A solid polymer electrolyte membrane, wherein an elastic body is disposed so as to surround the first region. The solid polymer electrolyte membrane according to claim 1, wherein a layer made of only an ion exchange resin is disposed on at least one surface of the packed layer. The solid polymer electrolyte membrane according to claim 1 or 2, wherein a manifold hole is formed in the second region. The through hole in the first region has an average area of 1 × 10 ^{−3 to} 20 mm ² per piece, and the first region has an aperture ratio of 30 to 80%. The solid polymer electrolyte membrane described. The third region has a third region at the boundary between the first region and the second region, and in the third region, an opening is formed by the through hole from the first region to the second region. The solid polymer electrolyte membrane according to any one of claims 1 to 4, wherein the rate gradually decreases. In the third region, an average area per one of the through holes gradually decreases from the first region to the second region, or the through holes per unit area are reduced. The solid polymer electrolyte membrane according to claim 5, wherein the number is gradually reduced. A membrane electrode assembly for a fuel cell having the solid polymer electrolyte membrane according to any one of claims 1 to 6, comprising a catalyst layer containing a catalyst on both sides of the solid polymer electrolyte membrane, The membrane electrode assembly, wherein the catalyst layer is disposed inside a region surrounded by the elastic body. A gas diffusion layer is provided on at least one outer surface of the catalyst layer,
The membrane electrode assembly according to claim 6 or 7, wherein an outer edge portion of the gas diffusion layer is disposed on the outer peripheral side of the first region in the solid polymer electrolyte membrane.

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