JPH11224677A - Solid high polymer fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid high polymer fuel cell having high generating capacity per unit volume, manufactured at a lower cost. SOLUTION: This solid fuel cell has a power generating layer 1 composed of a film-like electrolytic layer 2 of a solid filtering hydrogen ions, two positive and negative conductive electrode layers 41, 42 pinching the layers 2 from both sides and including catalyst layers 31, 32, and metal nets 51, 52 integrally joined to both sides surfaces of the electrode layers 41, 42. The power generating layer 1 is formed into a corrugated-sheet-like bumpy shape by a shape-holding function of the metal nets 51, 52, and is pinched by the separators 61, 62 from both sides. Surface area of the power generating layer 1 connecting with fuel gas chambers 10 formed between the separators 61, 62 and oxidizing gas chambers 20 is enlarged, consequently the power generating capacity is improved. Also, manufacture's costs are lowered because stainless-steel flat plates can be used as the separators 61, 62.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polymer electrolyte fuel cell [PEFC (Polymer Electrolyte Fuel Cell).
l), also referred to as a polymer electrolyte fuel cell].

[0002]

2. Description of the Related Art In general, a fuel cell is a fuel cell in which different types of reactants such as a fuel gas and an oxidizing gas are supplied to both electrode portions which are joined to each other with an electrolyte layer containing an electrolyte interposed therebetween. Is a kind of generator that obtains electromotive force by chemical reaction. However, unlike a normal power generator, there is no mechanically or mechanically operating part inside the fuel cell, and power is generated only by a chemical reaction. Also, unlike ordinary chemical batteries, the reactants are continuously supplied from the outside and the products are continuously discharged to the outside, so continuous operation for an extremely long time is possible and there is no need for charging. .

[0003] There are several types of fuel cells. Among them, polymer electrolyte fuel cells usually have an operating temperature of 10%.
Since the temperature is as low as 0 ° C. or less, not only the start-up time can be shortened, but also the power density is as high as about 3 kW / m ² , so that there is an excellent advantage that the size and weight can be reduced. Therefore, a polymer electrolyte fuel cell is regarded as the most promising power supply battery for electric vehicles including hybrid vehicles, and research and development are being vigorously conducted in various places.

As shown in FIG. 14, a polymer electrolyte fuel cell comprises a solid polymer electrolyte layer containing an ion-exchange polymer electrolyte through which proton ions (H ⁺ ) are permeable, and a catalyst sandwiched between the two layers from both sides. It has positive and negative electrode layers that carry the layers, and a partition member (separator) that sandwiches both electrode layers. A fuel gas chamber and an oxidizing gas chamber are formed between the partition members and the electrode layers, respectively, and a fuel gas such as a reformed gas containing hydrogen and an air containing oxygen are provided in both chambers. An oxidizing gas such as is supplied from outside. Then, a chemical reaction occurs in both catalyst layers, which are supplied with hydrogen gas and oxygen gas from both chambers, and protons having a positive charge passing through the solid polymer electrolyte layer are generated from the negative electrode layer side. Since it moves to the positive electrode layer side, an electromotive force is generated, and a power generation action occurs.
As a result, electric power is generated from the polymer electrolyte fuel cell, and the electric power can be taken out through the conductive partition member to drive the motor M and the like.

Here, a layer including a solid polymer electrolyte layer and a positive / negative electrode layer and having a power generating action is referred to as a “power generating layer”.
I will call it. The power generation capacity of a polymer electrolyte fuel cell is a characteristic (electrode efficiency) per unit area of a power generation layer that converts both gases into electric energy, provided that the amounts of supplied fuel gas and oxidizing gas are constant. And the total area of the power generation layer. Therefore, when both gases are supplied sufficiently, the larger the total area (reaction area) of the power generation layer, the larger the amount of electric energy generated.
Therefore, if the electrode efficiency is constant, it is necessary to increase the reaction area in order to increase the output, and the size (volume) of the polymer electrolyte fuel cell increases almost in proportion to the output. Will do.

On the other hand, a polymer electrolyte fuel cell developed for the purpose of being mounted on an electric vehicle or the like is required to have a large power generation capacity while being small and lightweight. As described above, since the size of the polymer electrolyte fuel cell increases almost in proportion to the output, it is easily understood that this demand for obtaining a large output while being small and lightweight is a conflicting demand.

As a prior art which meets such a demand, there is, for example, a fuel cell having a structure disclosed in Japanese Patent Application Laid-Open No. H4-154047. In the same publication, ribs are provided on partition walls (separators) facing each other in parallel with each other, so that the ribs on one partition member engage with grooves between the ribs on the other partition member. A fuel cell (prior art 1) in which the shape of a power generation layer is held in a corrugated shape by protrusions of both partition members is disclosed. In this fuel cell, the power generation layer is folded and shortened in a direction perpendicular to the ridges, and the reaction area per unit length increases, so the effect of improving the power generation capacity per unit volume of the fuel cell is said to be an effect. ing.

The publication also discloses that between the partition members on both sides (and the fuel gas chamber and the oxidizing gas chamber) and the power generation layer,
There is also disclosed a fuel cell (prior art 2) in which a porous shape holding member having trapezoidal ridges parallel to each other is interposed, and the shape holding members engage with each other to sandwich the power generation layer.
The effect of improving the power generation capacity per unit volume of the fuel cell has been claimed as an effect of this fuel cell for the same reason as the above-described fuel cell.

[0009]

However, the above-mentioned prior art 1 requires a partition member (separator) with a ridge, and the above-mentioned prior art 2 requires a shape holding member with a ridge. Therefore, the structure becomes complicated. In addition, since the power generation layer also needs to be processed in accordance with the position of the ridge, the power generation layer also needs to be processed with high precision. Therefore, in the prior art, the number of processing steps for both the partition member or the shape maintaining member and the power generation layer is increased, and there is a disadvantage that the manufacturing cost of the fuel cell is increased.

Further, in the above-mentioned prior art 1, since there are ridges formed on the partition member, the flow path of the fuel gas (fuel gas chamber) and the flow path of the oxidizing gas (oxidizing gas chamber). And the effective channel is narrowed. As a result, the power generation capacity of the power generation layer having an increased surface area may be reduced. Furthermore, in the above-mentioned prior art 2, since a porous shape retaining member is required, the surface of the power generation layer does not directly contact the flow path of the fuel gas and the oxidizing gas, and the power generation efficiency is reduced.
The number of parts increases and the manufacturing cost increases. Since the porous shape holding member is in contact with the entire surface of the electrode layers on both sides of the power generation layer, the power generation efficiency is reduced unless a porous material having a considerably high aperture is used for the shape holding member. It is inevitable that it will become even larger. On the other hand, when the partition member is formed from a porous material having a very large opening degree, the partition member is more likely to be cracked or chipped during processing, and the yield rate of the product is reduced, so that the manufacturing cost is further increased.

Therefore, an object of the present invention is to provide a polymer electrolyte fuel cell having a higher power generation capacity per unit volume and a lower production cost.

[0012]

In order to solve the above problems, the inventor has invented the following means. (First Means) A first means of the present invention is a polymer electrolyte fuel cell according to claim 1. Here, both electrode layers are formed of a conductive porous body made of carbon or the like, and play a role of gas diffusion and conductivity. In a polymer electrolyte fuel cell, a catalyst layer carrying a catalyst such as platinum is usually formed in contact with the polymer electrolyte layer.

This catalyst layer is usually formed by bonding to both surfaces of the solid polymer electrolyte layer, and is often formed in a separate step from the electrode layer. In the description, the catalyst layer is defined as being included in the electrode layer as a part of the electrode layer. In other words, a conductive layer that is in close contact with both surfaces of the solid polymer electrolyte layer and carries the catalyst is defined as an electrode layer. In the electrode layer, a power generation reaction occurs even at a relatively low temperature of 100 ° C. or less due to the action of the catalyst. Therefore, if the definitions are the same, the electrode layer may be replaced with the catalyst layer.

In this specification, a multilayer body including a solid polymer electrolyte layer and both electrode layers (including a catalyst layer), including a shape holder, is referred to as a power generation layer. . According to this means, the power generation layer composed of the solid polymer electrolyte layer and the electrode layer is formed into an uneven shape, and has a rigid shape holder for maintaining the uneven shape. Therefore, even when the uneven shape holding structure such as the ridge is not formed on the partition member, the uneven shape of the power generation layer is manufactured by the rigidity of the shape holder of the power generation layer, that is, the rigidity of the power generation layer itself. It is kept in the shape of irregularities as molded in the process.

As a result, unlike the above-described prior art, a rib is provided on the partition wall member to maintain the uneven shape of the power generation layer, or a porous member that holds the power generation layer from both sides to maintain the uneven shape. There is no need to provide a shape holding member, and the cost is reduced. In addition, the flow passage is not narrowed by the ribs of the partition member, and the contact between the power generation layer and both gases is reduced by the porous shape holding member, so that the power generation capacity of the power generation layer is not reduced. Therefore, the power generation capacity per unit volume is improved.

Therefore, according to this means, it is possible to provide a polymer electrolyte fuel cell having a higher power generation capacity per unit volume and a lower production cost. In this means, also in this means, similar to a normal fuel cell, the partition member is used as a conductive separator,
Unit cells (single cells = one layer of fuel cells) can be stacked in series to increase the power generation voltage. Rather, the stacking of the unit cells of the polymer electrolyte fuel cell in this manner to constitute a fuel cell is a common and desirable operation.

For the purpose of improving the rigidity of the partition member, a reinforcing rib may be provided on the surface of the partition member. Although the reinforcing rib is a kind of ridge, unlike the ridge of the prior art 1 for maintaining the shape of the power generation layer, the size is small. In addition, since it is not necessary to form reinforcing ribs for all the concave and convex concave portions of the power generation layer, the number of reinforcing ribs can be reduced. Therefore, the manufacturing cost of the partition member does not increase so much. In addition, since the reinforcing ribs do not need to be engaged with all of the concavities and convexities of the power generation layer, dimensional accuracy is not so much required, and the number of steps for assembling the power generation layer and the partition member is hardly increased. as a result,
With almost no increase in the production costs of this means,
It is possible to form a reinforcing rib on the partition member.

(Second Means) A second means of the present invention is a polymer electrolyte fuel cell according to the second aspect. In this means, the shape holder is integrally joined to at least one surface of both electrode layers of the power generation layer. The shape holder is desirably a porous material having a high porosity and a good conductor, such as a wire mesh made of a fine metal wire and having a coarse mesh. According to this means, the rigidity holding member for holding the formed uneven shape is integrally joined to at least one surface of both electrode layers of the power generation layer. The irregular shape formed with the rigidity can be maintained.

In addition, joining the shape holder to the surface of the electrode layer can be easily performed by a method such as pressure bonding at the time of forming the electrode layer, and thus has an effect of reducing the manufacturing cost. Therefore, according to this means, similarly to the first means, there is an effect that the power generation capacity per unit volume is higher and the manufacturing cost is lower. By the way, the electrode layer to which the shape holding body is joined has a gas permeability to the catalyst layer carried on the side of the solid polymer electrolyte layer facing away from the shape holding body, and the collection from the catalyst layer. It is desirable to have three properties of electrical conductivity and shape retention. When the shape holder is bonded to only one of the surfaces of the two electrode layers, the gas flow to the catalyst layer is higher in the one electrode layer than in the other electrode layer to which the shape holder is not bonded. It is common for the permeability to be somewhat reduced. Therefore, it is theoretically or experimentally confirmed whether a higher power generation capacity is obtained when the shape holder is bonded to either the positive or negative electrode layer. It is desirable to join the shape holder to the electrode layer.

(Third Means) A third means of the present invention is a polymer electrolyte fuel cell according to the third aspect. In this means, at least one of the two electrode layers includes the shape holder. The shape holder is desirably a porous material having a high porosity and a good conductor, such as a wire mesh made of a fine metal wire and having a coarse mesh. In this means, since the shape retainer having rigidity for holding the formed uneven shape is included in at least one of the two electrode layers of the power generation layer, the power generation layer is formed with its own rigidity as described above. The uneven shape can be maintained.

Including a shape holder integrally with or inside the electrode layer can be easily achieved by a method such as mixing the shape holder or its material when forming the electrode layer. This has the effect of reducing the manufacturing cost. Therefore, according to this means, similarly to the first means, there is an effect that the power generation capacity per unit volume is higher and the manufacturing cost is lower.

By the way, the electrode layer including the shape-retaining body has a gas permeability to the catalyst layer carried on the solid polymer electrolyte layer side, a current collecting property from the catalyst layer, and a shape-retaining property. It is desirable to have three properties sufficiently. When only one of the two electrode layers contains the shape holder, the gas permeability to the catalyst layer of the one electrode layer is higher than that of the other electrode layer to which the shape holder is not joined. Is usually somewhat reduced. Therefore, it is theoretically or experimentally confirmed whether a higher power generation capacity can be obtained when the shape holder is included in either the positive or negative electrode layer, and the electrode with the higher power generation capacity is obtained. It is desirable to include a shape carrier in the layer.

(Fourth Means) A fourth means of the present invention is a polymer electrolyte fuel cell according to the fourth aspect. In this means, the solid polymer electrolyte layer, which is an intermediate member of the power generation layer, includes the shape holder. The shape holder is desirably a nonporous, porous material having a high porosity, such as a coarse resin net made of resin fibers. In this means, since the shape retainer having rigidity to hold the formed uneven shape is included in the solid polymer electrolyte layer in the middle of the power generation layer,
The power generation layer can maintain the uneven shape formed by its own rigidity as described above.

Including the shape holder integrally with or inside the solid polymer electrolyte layer can be achieved by mixing the shape holder or its material when forming the solid polymer electrolyte layer. It can be easily done by a method such as setting. That is, first, while the polymer electrolyte material (for example, perfluorosulfonic acid polymer) forming the solid polymer electrolyte layer is softened, the temperature is raised in a temperature range in which the characteristics as the electrolyte are not deteriorated. Then, in this state, by pressing the shape holder that can withstand the temperature, it is possible to integrally include the shape holder in the solid polymer electrolyte layer.

Alternatively, an ion exchange resin such as a perfluorosulfonic acid polymer for forming a solid polymer electrolyte layer is dissolved in an appropriate solvent to form a solution, and the solution is impregnated into a film-like porous body having insulating properties and continuous pores. To form a solid polymer electrolyte layer. In this case, if the porous body is formed from a plastic material (for example, a thermoplastic resin), the solid polymer electrolyte layer has the porous body as a shape holding body and has a shape holding function.

As still another method, a film-like solid polymer electrolyte material is superimposed on one or both sides of the porous body, and hot pressed to inject the electrolyte material into the pores of the porous body. A solid polymer electrolyte layer including a shape holder can be formed. Alternatively, a resin net, a resin nonwoven paper, and a fibrous or flake-shaped resin material are mixed into the above-described electrolyte solution of the ion exchange resin, and a film forming method such as a casting method or a blade method is used.
A solid polymer electrolyte layer including a shape retainer can also be manufactured.

It is relatively easy to carry out any of the methods for producing a solid polymer electrolyte layer containing the shape holder.
Therefore, according to this means, similar to the above-described first means,
There is an effect that the power generation capacity per unit volume is higher and the manufacturing cost is lower. By the way, the solid polymer electrolyte layer including the shape retainer needs to have three properties: permeability of protons as cations, insulating property to insulate both electrode layers from each other, and shape retainability. is there. Therefore, it is desirable that the shape retainer be as thin as possible, be a porous material having a large porosity, be nonconductive, and be excellent in wettability with the electrolyte material. Is desirable.

(Fifth Means) A fifth means of the present invention is a polymer electrolyte fuel cell according to the fifth aspect. In this means, the shape holder is formed of any one of a metal net, a metal porous plate, a metal nonwoven paper, and a metal fiber, and is integrally joined to at least one surface of both electrode layers. Or included in at least one of the two electrode layers.
Therefore, the following two effects can be obtained roughly.

First, the conductivity (that is, current collecting property) of the electrode layer having the shape holder is greatly improved, and the loss of electric energy due to Joule heat in the electrode layer is reduced.
The power generation capacity is further improved. In particular, in a configuration in which a metal shape holder is bonded to at least one surface of both electrode layers, conductivity is improved at a contact point with a partition member, which is a separator usually made of a good conductor, and contact resistance is significantly increased. Reduced to Therefore, loss of electric energy due to contact resistance in the contact line between the electrode layer and the partition member is reduced,
The power generation capacity is further improved.

Second, if a proper type of metal material is selected, good formability due to plastic deformation of the metal can be obtained, so that the power generation layer can be easily formed into an uneven shape.
Manufacturing costs can be further reduced. Therefore, according to this means, in addition to the effects of the above-described second means or third means, there is an effect that further improved power generation capability and extremely good workability can be simultaneously obtained.

(Sixth Means) A sixth means of the present invention is a polymer electrolyte fuel cell according to the sixth aspect. In this means, the shape retainer is a resin net, a resin porous plate, a resin nonwoven paper,
It is formed of one of a resin powder and a resin fiber, and is integrally joined to at least one surface of both electrode layers, or is included in at least one of both electrode layers. Therefore, the following two effects can be obtained roughly.

First, if an appropriate type of resin material is selected for the material of the shape holder, the electrode layer or the solid polymer electrolyte layer having the shape holder will have an uneven shape due to the excellent plasticity of the resin. Excellent molding processability can be obtained at the time of molding. Secondly, in the configuration in which the shape holder made of a resin material is included in the electrode layer, in addition to the shape holding function, the shape holder can also function as a binder such as carbon forming the electrode layer. it can. Therefore, the necessity of adding a binder in addition to the resin as the shape holder is reduced, and the electrode layer can be formed with little or no need for a binder other than the shape holder. As a result, there is almost no increase in the manufacturing cost required for adding the shape holder.

Therefore, according to this means, in addition to the effects of the above-described second to fourth means, good moldability can be obtained. Further, when the shape holder is included in the electrode layer as a binder, This has the effect that the manufacturing cost can be further reduced. The solid polymer electrolyte layer is usually made of a perfluorosulfonic acid polymer, and the softening temperature of the polymer is about 130 ° C. Therefore, when a thermoplastic resin is used as the resin forming the shape holder,
It is desirable to employ a thermoplastic resin having a softening temperature close to the above softening temperature.

It is known that the properties of an electrolyte of a perfluorosulfonic acid polymer are deteriorated when heated to a heat-resistant temperature of about one hundred and several tens of degrees Celsius. Therefore, when a thermoplastic resin is employed as the material of the shape holder, it is desirable that the softening temperature is lower than the above-mentioned heat-resistant temperature. For the same reason, when a thermosetting resin is used as the material of the shape holder, the curing temperature of the thermosetting resin is desirably lower than the above-mentioned heat-resistant temperature.

(Seventh Means) A seventh means of the present invention is a polymer electrolyte fuel cell according to claim 7. In this means, the uneven shape on which the power generation layer is formed is a corrugated sheet shape, a three-dimensional corrugated sheet shape by Miura folding, and a mesh in which concave and convex portions are arranged in a triangular or quadrangular mesh shape adjacent to each other. It is one of the irregular shapes.

First, when the uneven shape is a corrugated plate shape, the forming process can be easily performed even when the power generation layer has almost no elasticity. It is cheap. Therefore, in this case, there is an effect that not only the manufacturing cost can be suppressed extremely inexpensively, but also the present invention can be applied to a case where the power generation layer has almost no elasticity.

Second, when the uneven shape is a three-dimensional corrugated sheet shape by Miura folding, the power generation layer is compressed in all directions in the plane (that is, both in the vertical and horizontal directions), so that the corrugated sheet is the above-mentioned corrugated sheet shape. As compared with the case, the surface area of the power generation layer per unit volume is dramatically increased. As a result, the power generation capacity per unit volume of the polymer electrolyte fuel cell dramatically increases, for example, to about one digit.

The flow path of the fuel gas (fuel gas chamber) and the flow path of the oxidizing gas (oxidizing gas chamber) have a zigzag and zigzag shape, so that the flow is usually laminar. The flow of the fuel gas and the flow of the oxidizing gas are disturbed, and turbulence is likely to occur. Therefore, fresh fuel gas and oxidizing gas always come into contact with each surface of both electrode layers of the power generation layer, so that the power generation capacity is further improved.

Accordingly, in this case, there is an effect that the power generation capacity per unit volume of the polymer electrolyte fuel cell is dramatically increased. In addition, since the three-dimensional corrugated sheet shape by Miura folding does not require expansion and contraction of the power generation layer, there is also the effect that even when the power generation layer has almost no elasticity, it can be easily formed into an uneven shape. is there.

Furthermore, the three-dimensional corrugated sheet shape formed by Miura folding is very unlikely to buckle under the compressive pressure from the partition members on both sides, so that the structural strength and rigidity are greatly improved.
Therefore, there is no need to attach reinforcing ribs or the like to the partition member to reinforce it. Even if the partition member is a flat plate, sufficient rigidity can be obtained, so that the manufacturing cost of the partition member can be reduced. There is also.

Third, when the irregular shape is a mesh-like irregular shape, not only does the surface area (reaction area) of the power generation layer per unit projected area increase, but also the flow of fuel gas and oxidizing gas. The direction of the road is not uniquely determined. That is, the flow directions of the two gases can be set to any directions, so that the fuel gas and the oxidizing gas can flow in directions orthogonal to each other. that way,
Since the fuel gas flow path and the oxidizing gas flow path at the outer edge of the polymer electrolyte fuel cell can be formed separately, the flow path configuration as a polymer electrolyte fuel cell system is simplified. . Regarding this advantage, there is no difference whether the uneven shape is a triangular mesh or a quadrangular mesh.

Therefore, in this case, there is an effect that the production of the polymer electrolyte fuel cell system is easy and inexpensive.

[0043]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a polymer electrolyte fuel cell according to the present invention will be clearly and fully described in the following examples so that those skilled in the art can understand the present invention. Example 1 (Structure of Example 1) As shown in FIG. 1, a polymer electrolyte fuel cell according to Example 1 of the present invention includes a polymer electrolyte membrane 2 and catalyst layers 31 and 32. Including electrode layers 41 and 42
And a power generation layer 1 composed of metal nets 51 and 52. The polymer electrolyte fuel cell according to the present embodiment further includes
A separator 6 serving as a partition member that forms the fuel gas chamber 10 and the oxidizing gas chamber 20 between the electrode layers 41 and 42 and the metal nets 51 and 52, respectively, facing the first and second metal layers 51 and 52.
1,62.

The solid polymer electrolyte layer 2 is a thin film of a perfluorosulfonic acid polymer, which is a film-like proton conductive resin (proton exchange resin) that transmits positively charged hydrogen ions (protons). For reference, a resin film commercially available from DuPont under the trade name Nafion can be used as a reference. Since the perfluorosulfonic acid polymer thin film develops proton conductivity when contained in an appropriate amount of water, water vapor is usually supplied from the outside to retain the water. However, in the polymer electrolyte fuel cell according to the present embodiment, since water is generated during the power generation reaction, it is not necessary to supply water vapor to the polymer electrolyte layer 2 from the outside.

The thickness of the solid polymer electrolyte layer 2 is desirably thin so as to reduce the internal resistance of the battery. Since the film may be damaged, an appropriate thickness is required in order to maintain strength. Therefore, in a normal polymer electrolyte fuel cell, the film thickness of the polymer electrolyte layer 2 is about 50 μm to one hundred and several tens μm, so that the film thickness of the polymer electrolyte layer 2 of this embodiment is 100 μm. And

The catalyst layers 31 and 32 are thin-film layers formed by being applied to both surfaces of the solid polymer electrolyte layer 2. In this embodiment, the catalyst layers 31 and 32 are formed as follows. That is, first, those obtained by dispersing and dissolving, in an alcohol-based solvent, fine particles in which mainly a platinum or an alloy thereof catalyst is supported on the surface of carbon black and an electrolyte composed of perfluorosulfonic acid are mixed together. A mixture in the form of a slurry (ie, a slurry or a paste) is prepared. Next, using the mixture, catalyst layers 31 and 32 are formed on both surfaces of the solid polymer electrolyte layer 2. The catalyst layers 31 and 32 are formed by direct application by screen printing or by indirect application such as transfer.

The thickness of the catalyst layers 31 and 32 is usually several μm.
In the present embodiment, the part which is restricted by the diffusion of the reaction gas and actually contributes to the reaction is set to about 10 μm on average, which is optimal in view of the range of several μm. Therefore, the mechanical strength of the catalyst layers 31 and 32 mainly depends on the solid polymer electrolyte layer 2. The catalyst layers 31 and 32 are thin films each having a thickness one digit thinner than the solid polymer electrolyte layer 2, and are porous thin films in which a catalyst metal (platinum or an alloy thereof) is supported on the surfaces of fine particles of carbon black. It is. Therefore, the fuel gas and the oxidizing gas can enter the insides of the catalyst layers 31 and 32, respectively, and a power generation reaction occurs.

In forming the two catalyst layers 31 and 32, the composition of the catalyst layer 31 in contact with the fuel gas and the catalyst layer 32 in contact with the oxidizing gas are slightly changed, and the electrode efficiency (efficiency of the power generation reaction) is changed. Can be optimized to be larger. Specifically, the catalyst layer 31 that comes into contact with the fuel gas has a large contact area with the humidifying water vapor. On the other hand, the catalyst layer 32 that comes into contact with the oxidizing gas contains the oxidizing gas (oxygen).
The structure is such that the diffusion of water is facilitated and the drainage of generated water is facilitated.

The catalyst layers 31 and 32 and the electrode layers 41 and 42 described later are common in that carbon is used as a base material and is conductive. Therefore, in this specification, the catalyst layers 31 and 32 are defined as being included in the electrode layers 41 and 42 as a part of the electrode layers 41 and 42. The electrode layers 41 and 42 excluding the catalyst layers 31 and 32 are joined to the solid polymer electrolyte layer 2 having the catalyst layers 31 and 32 formed on both surfaces, and the positive and negative electrodes sandwiching the solid polymer electrolyte layer 2 from both sides are provided. It is a two-layer conductive porous layer. The thickness of each of the electrode layers 41 and 42 excluding the catalyst layers 31 and 32 is 100 to 40.
It is about 0 μm.

The electrode layers 41 and 42 excluding the catalyst layers 31 and 32
Means that the fuel gas and the oxidizing gas can be easily
In order to be able to penetrate into No. 2, it is necessary to be excellent in gas permeability. Further, in order to function as a conductive layer, it is necessary to have excellent electron conductivity. Therefore, the electrode layers 41 and 42 except for the catalyst layers 31 and 32 are formed by applying a mixture obtained by mixing short carbon fibers, a binder, and a dispersion medium into a paste on the surfaces of the catalyst layers 31 and 32 by a blade method. After the application, it is dried to remove the dispersing medium and formed.

Here, if the carbon short fiber is too long, it will be an obstacle when forming into a concave-convex shape later. Therefore, it is desirable that the carbon short fiber has an appropriate length.
Carbon short fibers having a major axis and a minor axis ratio of about 1: 5 to about 20 are employed. Also, as the binder, any of a dispersion type and a dissolution type can be used,
In this embodiment, a dispersion type acrylic emulsion binder is employed. Therefore, although water is employed as the dispersion medium, the binder does not re-dissolve in water after drying, so that the electrode layers 41 and 32 except for the catalyst layers 31 and 32 are used.
42 is formed stably. The mixing ratio of the short carbon fiber, the binder, and the dispersion medium is approximately 95:
5: 100. The mixing ratio is set in consideration of the workability at the time of coating and the void state after drying. However, depending on the shapes and sizes of the carbon short fibers and the binder, the characteristics of the electrode layers 41 and 42 are the same even at the same mixing ratio. Is affected. Therefore, the above-mentioned numbers of the mixing ratios are only a rough guide, and ultimately need to be adjusted based on the actual test results.

As a general tendency, as the ratio of the short carbon fibers is increased, the strength of the electrode layers 41 and 42 is reduced unless the amount of the binder is correspondingly increased.
There is also a possibility that the material 42 may be peeled off. Conversely, when the amount of the binder is large, the electron conductivity is reduced, and
There is a possibility that the catalyst layers 31 and 32 may be excessively coated and hinder contact with the gas. Also, if the dispersion medium is too small,
Since the fluidity of the mixture decreases, the workability of the coating operation and the surface properties after drying tend to be inferior (therefore, the electrode layers 41 and 42 except for the catalyst layers 31 and 32 are separately prepared, The catalyst layers 31 and 32 are formed by a method such as bonding or hot pressing.
May be bonded to the surface). Therefore, the mixing ratio needs to be set appropriately.

Further, in order to disperse the short carbon fibers in water, which is a dispersion medium, it is desirable to dissolve a surfactant in water. However, the electrode layer 41,
Since it is necessary to prevent the surfactant remaining in 42 from adversely affecting the battery performance, a nonionic surfactant is employed as the surfactant in the present embodiment. About 2% by weight is added.

When a solvent-type polyvinylidene fluoride or styrene-based binder is used as the binder, an organic solvent is generally used as a dispersion medium. Depending on the type, water can be used as the dispersion medium. In this embodiment, the thickness of the electrode layers 41 and 42 excluding the catalyst layers 31 and 32 is 50 to 1
It is formed to a thickness of about 00 μm. The reason why the electrode layers 41 and 42 are formed so thin is that the metal nets 51 and 5 described below are used.
2 is responsible for the shape maintaining function.
This is because the shape holding function is not required for 42.

The metal nets 51 and 52 are made of S having a wire diameter of 100 μm.
It is a coarse mesh made of US316 stainless steel, and the interval between the stainless steel wires forming the metal meshes 51 and 52 is about 100 to 400 μm. Metal nets 51, 52
Has a function as a shape holder, and has both electrode layers 41, 4
2 are integrally joined by thermocompression bonding. At this time, the binder of the electrode layers 41 and 42 is
And an electrode layer 41, 42, and a metal net 51, 52 is held on both surfaces of the electrode layers 41, 42, respectively.

The metal mesh 5 for the electrode layers 41 and 42
When the joining force of the metal nets 51 and 5 is insufficient,
If the above-mentioned binder is applied to the side to be bonded to the second electrode layers 41 and 42, a sufficient bonding force can be obtained. However, it is necessary to apply the binder with care so as not to form a film between the meshes of the metal nets 51 and 52. If the film is formed, the film is blown through air or the like. Good to keep.

As described above, the power generation layer 1 including the solid polymer electrolyte layer 2, the electrode layers 41 and 42 including the catalyst layers 31 and 32, and the metal nets 51 and 52 is formed. Thereafter, the power generation layer 1 is wound around a pair of gear-shaped heating rolls, and is formed into a corrugated corrugated shape by heating. The joining of the metal nets 51 and 52 to the electrode layers 41 and 42 by hot pressing and the forming by corrugated plate-shaped unevenness by heating press are simultaneously performed by the above-mentioned heating roll or two opposed dies. It is also possible.

That is, the power generation layer 1 including the solid polymer electrolyte layer 2 and the two electrode layers 41 and 42 is formed into a corrugated uneven shape and has a rigidity to maintain the uneven shape. It has metal nets 51 and 52 as shape holders. Therefore, unlike the fuel cell of the prior art, in order to maintain the uneven shape, a special surface shape is given to the separators 61 and 62, or the porous uneven shape holding member is replaced with the power generation layer 1.
There is no need to sandwich the filter between the separators 61 and 62.

Here, for example, if the power generation layer 1 is formed so that the apex angle of the uneven shape is 60 degrees, the separators 61 and
Since the two sides of the power generation layer 1 having the same length are formed with respect to the base formed by the power generation layer 2, the power generation capacity twice as high as that of the flat power generation layer 1 can be obtained. The thickness of the power generation layer 1 having the uneven shape corresponding to the distance between the separators 61 and 62 is 1 to 2 mm.
And one side of the power generation layer 1 is about 1.2 to 2.3 mm.

The separators 61 and 62 serving as partition members are
A fuel gas chamber 10 through which a fuel gas such as a reformed gas containing hydrogen gas flows and an oxidizing gas chamber 2 through which an oxidizing gas such as air containing oxygen flows between the electrode layers 41 and 42, respectively.
0 is formed. The separators 61 and 62 are made of SUS316
Since it is formed from a stainless steel flat plate and has high corrosion resistance, it has excellent durability and is inexpensive in cost. Here, in the case where the corrosion resistance is insufficient on the oxidizing gas side in the separators 61 and 62, it is preferable that only the side in contact with the oxidizing gas or both surfaces be gold-plated very thinly.

The materials of the separators 61 and 62 include:
At present, a carbon material subjected to a gas impermeability treatment is usually used. However, since the material cost is high, a stainless steel plate having a low material cost is employed in this embodiment. Unlike the conventional fuel cell and the conventional fuel cell, the separators 61 and 62 do not need to form a large number of grooves in parallel and can be used as a flat plate.
The processing cost of 2 is also low.

The separators 61 and 62 serving as partition members are
The power generation layer 1 is sandwiched by contacting the metal nets 51, 52 covering the respective electrode layers 41, 42, and one single cell (unit battery)
To form When the separators 61 and 62 sandwich the power generation layer 1, a gas seal member for preventing two kinds of gases from mixing at an outer edge thereof, a spacer member for adjusting an interval between the separators 61 and 62, and the like are used. Is done. Also,
Each pipe for gas supply / discharge, an electric connection terminal for taking out generated electric power, etc. are attached, bolts for fixing the separators 61 and 62 and each member, and fixing each unit cell at a predetermined position. -A joining means such as a nut is also used.

Since the single cell of the polymer electrolyte fuel cell assembled as described above generates a single cell with a low voltage of less than 1 V, the number of single cells required to generate the required voltage is one. Are stacked and used in series. When a plurality of unit cells are stacked in this manner, the unit cells adjacent to each other share the separators 61 and 62 to achieve reduction in size and weight and reduction in internal resistance.

(Function and Effect of Embodiment 1) The polymer electrolyte fuel cell of this embodiment is configured as described above.
The following functions and effects are exhibited. First, in order to operate the polymer electrolyte fuel cell of the present embodiment, a fuel gas in which natural gas or the like is reformed to increase the content of hydrogen gas is blown into the fuel gas chamber 10, and the fuel gas chamber 10 is blown into the oxidizing gas chamber 20. An oxidizing gas, which is air containing oxygen, is blown. At this time, since the power generation reaction does not proceed very much when the power generation layer 1 is at room temperature, the fuel gas and the oxidizing gas which have been heated and heated to some extent are blown in for the purpose of raising the temperature of the power generation layer 1 to about 80 ° C. It is.

The fuel gas blown into the fuel gas chamber 10 reaches the catalyst layer 31 which is the fuel electrode while diffusing through the spaces between the metal nets 51 and through the porous electrode layer 41.
Decomposed into protons and electrons in the catalyst layer 31 (H ₂ → 2
H ^{+ +} 2e ^-). Proton (H ⁺ ) generated in catalyst layer 31
Pass through the solid polymer electrolyte layer 2 having an ion permeation function and reach the catalyst layer 32 which is the air electrode on the opposite side. On the other hand, oxygen reaches the catalyst layer 32, which is an air electrode, while diffusing through the metal net 52 and the electrode layer 42 in the catalyst layer 32, and the oxygen and the protons combine to generate water. Is absorbed (1 / 2O ₂ + 2H ⁺ +2
e ⁻ → H ₂ O). Incidentally, the entire reaction that occurs in the polymer electrolyte fuel cell is a reaction in which water is synthesized from oxygen and hydrogen (H ₂ + ／ O ₂ → H ₂ O), and is suitable for the polymer electrolyte membrane 2. As the water is supplied, exhaust gas containing water vapor is discharged from the oxidizing gas chamber 20.

Therefore, electrons flow out of the catalyst layer 31 and are output at a predetermined voltage from the separator 61 via the electrode layer 41 and the metal net 51 in this order. Conversely, electrons flow into the catalyst layer 32 from the separator 62 via the metal mesh 52 and the electrode layer 42 in this order. As a result, a current is extracted from the separator 62 toward the separator 61 at a predetermined voltage, and the polymer electrolyte fuel cell exhibits a power generation action.

The effects obtained by the polymer electrolyte fuel cell of this embodiment are roughly classified into the following two. The first effect is to increase the power output per unit volume.
In other words, the size and weight of the polymer electrolyte fuel cell are reduced.
The second effect is a reduction in the manufacturing cost of the polymer electrolyte fuel cell. That is, in the polymer electrolyte fuel cell of this embodiment, the polymer electrolyte layer 2 and the catalyst layer 3
The power generation layer 1 including the electrode layers 41 and 42 including
Metal nets 51 and 52 are formed in an uneven shape and have a rigid shape holding body for holding the uneven shape. Therefore, the separators 61 and 6 serving as partition members are provided.
Even if no uneven shape holding structure such as a ridge is formed on the power generation layer 2, the uneven shape of the power generation layer 1 depends on the rigidity of the metal nets 51 and 52, which are shape holders of the power generation layer 2, that is, the power generation layer 1 itself Due to the rigidity of the device, it is maintained in an uneven shape as molded in the manufacturing process.

As a result, unlike the above-described prior art, the ribs 61 and 62 serving as partition members are provided with ridges for maintaining the uneven shape of the power generation layer 1 or the power generation layer 1 is sandwiched from both sides. There is no need to provide a porous shape holding member for holding the uneven shape, and the cost is reduced. In addition, the power generation capacity of the power generation layer 1 is reduced because the flow path is narrowed by the protrusions of the separators 61 and 62 that are the partition members, and the contact between the power generation layer 1 and both gases is reduced by the porous shape holding member. Therefore, the power generation capacity per unit volume is improved.

The power generation layer 1 is formed in a corrugated shape as described above, and the area of the power generation layer 1 (power generation reaction area) is twice as large as the projected area. Power generation capacity per unit volume twice that of the polymer electrolyte fuel cell described above. Here, it is easier to form the power generation layer 1 in a corrugated plate-like uneven shape than to form the power generation layer 1 in another uneven shape, and to form the power generation layer 1 in another uneven shape. The effect that the molding cost is reduced is also obtained.

Further, a metal net 5 having a high electrical conductivity
Electrodes 1 and 52 cover the surfaces of the electrode layers 41 and 42, and electrons entering and exiting the catalyst layers 31 and 32 need to be conducted over a long distance inside the electrode layers 41 and 42 having relatively low electric conductivity. Absent. That is, the catalyst layers 31 and 32 pass through the inside of the metal nets 51 and 52 having a high electric conductivity from a part of the metal nets 51 and 52 which are closest to the metal nets 51 and 52 and pass through the separator 6.
It conducts to 1,62. Therefore, the internal resistance of the polymer electrolyte fuel cell is reduced, and power is more efficiently extracted from the polymer electrolyte fuel cell.

Therefore, according to the polymer electrolyte fuel cell of this embodiment, not only the power generation capacity per unit volume is higher, the size is smaller and lighter, but also the production cost is lower. (Modification 1 of Embodiment 1) As a modification 1 of the present embodiment, as shown in FIG.
It is possible to implement a polymer electrolyte fuel cell integrally joined to the surface of only the electrode layer 41 on the side of the fuel gas chamber 10 among the two electrode layers 41 and 42.

In this modification, a metal net 51 having a wire diameter of 100 μm is inserted into the electrode layer 41 having a thickness of 50 μm by hot pressing. Therefore, the metal net 51 is connected to the electrode layer 4.
Due to the adhesive action of the first binder, it is integrally joined to the electrode layer 41. Further, since the metal net 51 is joined to only the surface of the electrode layer 41 on the fuel gas chamber 10 side, there is no metal net exposed to the oxidizing gas, and the metal net 51 is less likely to be deteriorated by oxidative corrosion. Therefore, as the material of the metal net 51, inexpensive stainless steel or the like can be used with confidence. Further, since there is no metal net 52 on the oxidizing gas chamber 20 side, the manufacturing cost can be reduced accordingly.

Therefore, according to the polymer electrolyte fuel cell of the present modified embodiment, there is an effect that further inexpensive manufacturing cost and longer life can be realized while substantially maintaining the effects of the first embodiment. (Modification 2 of Embodiment 1) As Modification 2 of the present embodiment, the uneven shape of the power generation layer 1 is changed from the corrugated plate shape of Embodiment 1, and as shown in FIGS. A solid polymer fuel cell having a three-dimensional corrugated shape by Miura folding can be implemented.

Here, as shown in the development view in FIG. 3, the Miura folding means that the plane is divided into parallelogram sections which are congruent with each other, and the mountain fold and the valley fold are appropriately repeated to thereby reduce the distortion. This is a plane folding means for three-dimensionally folding without wrinkling. The plane folded by the Miura fold is equivalent no matter which section of the plane is taken, and there is no local extension or compression as in the normal folding method. By the way, Miura folding is a method of folding a plane invented by Professor Miura of the Institute of Space and Astronautical Science, and it accommodates a flat space structure with a large area like a solar cell panel with a very narrow space at the tip of the launch rocket. It is used for the purpose of folding and storing it.

In this modification, as shown in FIGS. 4 and 5 again, the fuel gas chamber 10 and the oxidizing gas chamber 20, which are the flow paths of the fuel gas and the oxidizing gas, have a complicated folded shape. It is bent. That is, as can be seen by comparing FIG. 3 which is a developed view and FIG. 4 which is a plan view in a state of being folded while leaving the flow path, the power generation layer 1 is compressed both vertically and horizontally to reduce the projected area. It is getting smaller. For example, the vertical dimension is folded to 1/4 and the horizontal dimension is 1/2.
, The projected area is reduced to 1/8 while the power generation reaction area is kept as it is.

The fuel gas flow path (fuel gas chamber 10)
And the flow path of the oxidizing gas (oxidizing gas chamber 20) has a zigzag bent shape, so that the flow of the fuel gas and the flow of the oxidizing gas, which are usually laminar flows, are disturbed. Turbulence is likely to occur. Therefore, fresh fuel gas and oxidizing gas always come into contact with the respective surfaces of the two electrode layers 41 and 42 of the power generation layer 1, so that the power generation capacity is further improved.

Therefore, according to the polymer electrolyte fuel cell of the present modified embodiment, the power generation capacity per unit volume is dramatically increased, and an increase of about one digit is expected. large. In addition, the three-dimensional corrugated sheet shape by the Miura fold does not require the expansion and contraction of the power generation layer 1. There is also an effect that can be done.

Further, as shown in FIG. 5 again, the three-dimensional corrugated sheet formed by the Miura fold hardly buckles against the compressive pressure from the separators 61, 62 on both sides, so that the structural strength and rigidity are improved. Is greatly improved. Therefore, it is not necessary to reinforce the separators 61 and 62 with reinforcing ribs and the like, and even if the separators 61 and 62 are flat, sufficient rigidity can be obtained.
There is also an effect that it is possible to reduce the manufacturing cost of 1,62.

(Third Modification of First Embodiment) As a third modification of the present embodiment, as shown in FIG. 6, a protrusion is provided along each flow path of the fuel gas and the oxidizing gas in the first embodiment. It is also possible to implement a polymer electrolyte fuel cell having separators 61 'and 62'. In the present modified embodiment, the purpose of forming the projections on the separators 61 ′ and 62 ′ is not to maintain the shape of the power generation layer 1, but also to form the separator not only in the projections but also in the depressions of the power generation layer 1 having the corrugated plate-like unevenness. 6
1 'and 62' are brought into contact with each other to improve current collection. That is, in the present modified embodiment, if a part of the separators 61 ′ and 62 ′ abuts also on the concave portion of the power generation layer 1 to collect current, the conductive distance required for current collection is halved, and the internal resistance is reduced by half. The purpose is to improve battery performance. Naturally, the projections of the separators 61 ′ and 62 ′ are formed to be thin to some extent so as not to narrow the fuel gas chamber 10 and the oxidizing gas chamber 20 very much, and extremely vertically stand on the plane of the separators 61 ′ and 62 ′. It may be a strip-shaped member.

Since the separators 61 'and 62' are made of stainless steel like the separators 61 and 62 of the first embodiment, it is desirable to manufacture them by press working in terms of cost. However, make the projection as a separate part,
Flat separator 6 by brazing, welding, fitting, etc.
It may be joined to 1 ', 62'. (Other Modifications of Embodiment 1) As another modification of this embodiment, in Embodiment 1, the metal net 51,
52, but a metal porous plate, metal non-woven paper, metal fiber, or the like is used instead of the metal mesh.
It is also possible to implement a polymer electrolyte fuel cell integrally joined to the surface of the fuel cell. According to the present modification, the same operation and effect as those of the first embodiment can be obtained. Also, with respect to this modified embodiment, it is possible to implement the modified embodiments corresponding to the modified embodiments 1 to 3 with respect to the first embodiment, and substantially the same operation and effect can be obtained in each modified embodiment.

Further, as still another modification of the first embodiment, a resin net, a resin porous plate, a resin non-woven paper, a resin fiber, or the like may be used as a shape holder instead of the metal nets 51 and 52. It is also possible to implement a polymer electrolyte fuel cell integrally joined to the surfaces of the layers 41 and 42. According to the present modification, the same operation and effect as those of the first embodiment can be obtained. Also, with respect to this modified embodiment, it is possible to implement the modified embodiments corresponding to the modified embodiments 1 to 3 with respect to the first embodiment, and substantially the same operation and effect can be obtained in each modified embodiment.

When the resin constituting the shape holder is a thermosetting resin, the perfluorosulfonic acid polymer forming the solid polymer electrolyte layer 2 is softened.
It is desirable to use a thermosetting resin that can be cured at about ° C. Alternatively, when the resin constituting the shape holder is a thermoplastic resin, the solid polymer electrolyte layer 2
It is desirable to use a thermoplastic resin that can be softened and molded at about 120 ° C. In any case, it is desirable that the molding temperature is set to 165 ° C. or less at which the characteristics of the polymer electrolyte layer 2 start to deteriorate.

Embodiment 2 (Structure of Embodiment 2) As shown in FIG. 7, a polymer electrolyte fuel cell according to Embodiment 2 of the present invention has two electrode layers 41 ',
42 ′ differs from the first embodiment in that it includes metal nets 51 ′ and 52 ′ as shape holders, and the other points are the same as the first embodiment.

The method for manufacturing a polymer electrolyte fuel cell according to the present embodiment uses the catalyst layers 31, 3 on both sides of the polymer electrolyte layer 2.
Steps up to the formation of 2 are the same as in the first embodiment.
Thereafter, the paste in which the carbon fine particles and the binder are dissolved or dispersed in a solvent or a dispersion medium is applied to the electrode layer 4.
The metal nets 51 ′ and 52 ′ are placed on the surfaces of the metal nets 1 and 42, and are applied by a method such as screen printing or blade printing. And when the solvent or dispersion medium evaporates,
Electrode layers 41 'and 42', which are porous bodies in which carbon fine particles are bonded to each other by a binder, are formed.
1 'and 42' are formed to include metal nets 51 and 52 therein. The diameter of the stainless steel wire forming each of the metal nets 51 ′ and 52 ′ is different from that of the first embodiment, and each of the electrode layers 41 ′ and 52 ′ is different from that of the first embodiment.
It is selected to be as thin as 42 'thickness (50 μm) or less.

After the power generation layer 1 is formed as described above, the power generation layer 1 is formed into a corrugated uneven shape and is sandwiched between the separators 61 and 62, as in the first embodiment. . (Effects of Embodiment 2) In this embodiment, the metal nets 51 'and 52' as shape holders are provided near the catalyst layers 31 and 32 and are partially in contact with each other. Layer 31,
Excellent conductivity is obtained between the metal mesh 32 and the metal nets 51 'and 52'. Furthermore, even in the contact lines between the separators 61 and 62 and the power generation layer 1, the metal nets 51 'and 52' are close to the surfaces of the separators 61 and 62 and may be partially in contact with each other. Since there is a metal net 51 ', 52'
Excellent conductivity is obtained between the separator and the separators 61 and 62. As a result, the catalyst layers 31, 32 and the separators 61, 6
2, excellent electrical conductivity is obtained, the internal resistance is reduced, the loss due to Joule heat is reduced, and the power generation characteristics of the polymer electrolyte fuel cell are improved to be equal to or more than those of Example 1.

In other respects, the same functions and effects as those of the first embodiment can be obtained. (Modification 1 of Embodiment 2) As Modification 1 of this embodiment, similarly to the first half of the other modifications of Embodiment 1 described above, a metal porous plate is used instead of a metal net as a shape holder. It is possible to implement a polymer electrolyte fuel cell employing metal nonwoven paper or metal fibers. According to this modification, substantially the same operation and effect as those of the second embodiment can be obtained.

(Modification 2 of Embodiment 2) As Modification 2 of this embodiment, a solid material in which a thermoplastic resin as a shape retainer is added to the electrode layers 41 and 42 instead of the metal nets 51 and 52 is used. Implementation of a polymer fuel cell is possible. That is, in the present modified embodiment, the electrode layers 41 and 42 are formed by transferring the catalyst layers 31 and 32 by a transfer method using a paste-like ink obtained by mixing thermoplastic resin fibers, carbon short fibers, a binder, and a dispersion medium. Formed on the surface. As the transfer film, a polyethylene film is used. Note that the ink may be applied to the surfaces of the catalyst layers 31 and 32 instead of the transfer method. The application method may be a screen printing method or a blade method.

At this time, the resin forming the thermoplastic resin fibers has good wettability with the dispersion medium and the binder, and softens at a temperature of about 120 ° C. at which the solid polymer electrolyte layer 2 softens. Select the resin to be used. Examples of such a resin include polyethylene. After the flat power generation layer 1 is formed in this manner, the temperature is raised to about 120 ° C. at which the solid polymer electrolyte layer 2 is softened, and the thermoplastic resin fibers are also softened. alike,
The power generation layer 1 is formed in a corrugated shape. as a result,
A polymer electrolyte fuel cell employing the power generation layer 1 having the electrode layers 41 and 42 containing thermoplastic resin fibers as shape holders therein is manufactured.

In this modification, the internal resistance of the polymer electrolyte fuel cell tends to increase somewhat because the thermoplastic resin fiber has no electrical conductivity unlike the metal net. However, as described in Modifications 3 and 4 below, the plasticity of the electrode layers 41 and 42 that are usually least likely to be deformed in the power generation layer 1 is improved, so that the power generation layer 1 expands and contracts. There is an effect that molding into a shape is also possible.

As a further modification of the present modification, a thermosetting resin is used in place of the thermoplastic resin as the resin material forming the resin fibers, and the temperature is about 120 ° C. at which the solid polymer electrolyte layer 2 softens. Implementation of a polymer electrolyte fuel cell that is molded and cured at temperature is also possible. (Variation 3 of Embodiment 2) As Variation 3 of the present embodiment, as shown in FIG. 8 (plan view) and FIG. It is possible to implement a polymer electrolyte fuel cell in which the projections are adjacent to each other and have a mesh-like uneven shape arranged in a square mesh. In this modification, the internal configuration of the power generation layer 1 contains resin fibers made of a thermoplastic resin or a thermosetting resin as the shape holder, as in the modification 2 of the above-described second embodiment.

Therefore, the molding process is carried out by sandwiching the power generation layer 1 between a pair of dies having irregularities opposed to each other. At this time, the temperature of the dies and the power generation layer 1 is controlled by the solid polymer electrolyte layer 2.
Of 120 ° C. or more, which is the softening temperature of the above, and less than 165 ° C., which is the deterioration temperature of the polymer electrolyte membrane 2. When the resin fiber is made of a thermoplastic resin, after the molding, the entire mold is cooled while being sandwiched between the molding dies, and the above-mentioned uneven shape is given to the thermoplastic resin fiber as the shape holder. When the resin fiber is made of a thermosetting resin, the resin is cured while being sandwiched between molding dies, and is allowed to harden. Then, the above-mentioned uneven shape is given to the thermosetting resin fiber as a shape holder.

In this modification, not only the surface area (reaction area) of the power generation layer 1 per unit projected area is increased, but also the directions of the flow paths of the fuel gas and the oxidizing gas are not uniquely determined. That is, the flow directions of the two gases can be set to any directions, so that the fuel gas and the oxidizing gas can flow in directions orthogonal to each other. By doing so, the flow path of the fuel gas and the flow path of the oxidizing gas at the outer edge of the polymer electrolyte fuel cell can be made separately, so that the flow path configuration as a system of the polymer electrolyte fuel cell Becomes simple.

Therefore, according to this modification, there is an effect that the production of the polymer electrolyte fuel cell system is easy and inexpensive. In this modification, the contact between the electrode layers 41 and 42 of the power generation layer 1 and the separators 61 and 62 is close to a point contact, which is disadvantageous in that the internal resistance of the polymer electrolyte fuel cell is further increased. Therefore, as a countermeasure, a conductive bonding agent (a thermosetting resin containing silver powder or the like) may be applied to the contacts between the electrode layers 41 and 42 and the separators 61 and 62 to increase the contact area.

(Modification 4 of Embodiment 2) As Modification 4 of the present embodiment, as shown in FIG. 10 (plan view) and FIG. It is also possible to implement a polymer electrolyte fuel cell that is formed into a network-like uneven shape arranged adjacently in a triangular network. Also in this modification, the internal configuration of the power generation layer 1 contains resin fibers made of a thermoplastic resin or a thermosetting resin as the shape holder, as in the modification 2 of the above-described second embodiment.

In this modification, the same operation and effect as those of the above-described modification 3 of the present embodiment can be obtained. (Modification 5 of Embodiment 2) As Modification 5 of the present embodiment, in Embodiment 2 and Modifications 1 to 4 described above, a resin net or a resin porous plate is used as a shape holder instead of the resin fiber. It is possible to implement a polymer electrolyte fuel cell using resin nonwoven paper or the like. According to this modification, substantially the same operation and effect as those of the above-described embodiment 2 and the modifications 1 to 4 can be obtained.

(Modification 6 of Embodiment 2) As Modification 6 of this embodiment, similar to Modification 2 of Embodiment 1 described above,
It is possible to implement a polymer electrolyte fuel cell in which the power generation layer 1 is formed into a three-dimensional corrugated sheet shape by Miura folding. According to this modification, substantially the same operation and effect as those of Modification 2 of the first embodiment can be obtained.

Embodiment 3 (Structure of Embodiment 3) As shown in FIG. 12, a solid polymer fuel cell as Embodiment 3 of the present invention
Reference numerals 1 'and 32' include resin fibers (thermoplastic resin or thermosetting resin) as shape holders, and include catalyst layers 31 'and 3'.
2 'itself has a function of maintaining the corrugated shape of the corrugated plate.

That is, the catalyst layers 31 'and 32' are made of a catalyst (platinum or its alloy supported on carbon).
, An electrolyte (perfluorosulfonic acid polymer), a conductive material (a carbon material having good conductivity such as graphite and carbon black), and resin fibers as a shape retainer. The catalyst layers 31 'and 32' are porous so that the gas can diffuse well.

On the other hand, the electrode layers 41 "and 42" are formed by impregnating a carbon woven fabric or a carbon non-woven fabric with a PTFE (polytetrafluoroethylene) resin, carbon black or the like. (Effects of Embodiment 3) In the polymer electrolyte fuel cell of this embodiment, the catalyst layers 31 'and 32' themselves have the function of maintaining the corrugated shape of the catalyst layers. Almost the same effects can be obtained.

(Modification 1 of Embodiment 3) As Modification 1 of this embodiment, when the catalyst layers 31 'and 32' have sufficient conductivity, the electrode layers except the catalyst layers 31 'and 32' 4
1 "and 42" may be omitted, and the catalyst layers 31 'and 32' may be brought into direct contact with the separators 61 and 62. According to the present modification, since the electrode layers 41 "and 42" can be omitted, the material cost and the processing cost can be reduced, and the manufacturing cost can be reduced. Not only that, but the catalyst layer 3
Since the fuel gas and the oxidizing gas directly touch and permeate the 1 'and 32', respectively, there is an effect that a further improvement in the power generation capacity can be expected.

(Other Modifications of the Third Embodiment) In the third embodiment and the first modification thereof, the catalyst layer 3
Since the power generation layer 1 has elasticity under predetermined conditions because the resin fibers are contained in 1 ′ and 32 ′, the unevenness of the power generation layer 1 is limited to a corrugated sheet shape or a three-dimensional corrugated sheet shape by Miura folding. Never be. That is, similarly to Modification 3 and Modification 3 of Example 2, the power generation layer 1 is formed into a mesh-like uneven shape in which the concave portion and the convex portion are arranged adjacent to each other in a triangular or quadrangular mesh. It is also possible. In this case, substantially the same operation and effect as those of the respective modified aspects in which the uneven shape is applicable can be obtained.

Embodiment 4 (Structure of Embodiment 4) As shown in FIG. 13, a polymer electrolyte fuel cell according to Embodiment 4 of the present invention has a shape holder on a polymer electrolyte membrane 2 '. The solid polymer electrolyte layer 2 'has a function of maintaining the corrugated shape of the corrugated sheet.

That is, first, an electrolyte alcohol solution of a perfluorosulfonic acid polymer and PTFE powder as a fluororesin were mixed at a predetermined ratio. After a while
A composite membrane composed of a porous shape support made of PTFE and a solid polymer electrolyte filling the pores was prepared by a casting method. The thickness of this composite film is about 100 μm. Then, the electrode layers 41 and 42 including the catalyst layers 31 and 32 were formed on the solid polymer electrolyte layer 2 ′ as the composite membrane in the same manner as in Example 1.

(Effects of Embodiment 4) In this embodiment, since the solid polymer electrolyte layer 2 'itself is provided with a shape maintaining function, the electrode layers 41 and 42 including the catalyst layers 31 and 32 are provided.
Are formed with an emphasis on gas diffusivity and current collecting function. As a result, according to this embodiment, there is an effect that it is possible to manufacture a polymer electrolyte fuel cell which is inexpensive and has excellent power generation capability.

(Various Modifications of Embodiment 4) In this embodiment, also, a modification in which the power generation layer 1 is formed into a three-dimensional corrugated sheet shape by Miura folding, which corresponds to Modification 2 of Embodiment 1, and Embodiment 2 It is possible to implement a modified embodiment in which the power generation layer 1 is formed in a network-like uneven shape corresponding to the modified embodiments 3 and 4.

In addition, by providing the electrode layers 41 and 42 with high conductivity, it is possible to reduce internal resistance and improve power generation capacity. Similarly, by giving the catalyst layers 31 and 32 themselves high conductivity,
It is possible to improve the reactivity of the battery by omitting the electrode layers 41 and 42, and at the same time, to reduce the internal resistance and improve the power generation capacity.

According to these various modifications, there is a tendency that substantially the same operation and effect as those of the corresponding various modifications described above are obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration of a polymer electrolyte fuel cell as Example 1.

FIG. 2 is a cross-sectional view illustrating a polymer electrolyte fuel cell according to Modification 1 of Example 1.

FIG. 3 is a developed view of a Miura fold forming a power generation layer according to a second modification of the first embodiment.

FIG. 4 is a plan view showing a concavo-convex shape of a power generation layer according to a second modification of the first embodiment.

FIG. 5 is a sectional view showing a polymer electrolyte fuel cell according to Modification 2 of Example 1;

FIG. 6 is a perspective view showing the shape of a separator according to a third modification of the first embodiment.

FIG. 7 is a cross-sectional view illustrating a configuration of a polymer electrolyte fuel cell as Example 2.

FIG. 8 is a plan view showing a concavo-convex shape of a power generation layer according to a third modification of the second embodiment.

FIG. 9 is a sectional view showing a polymer electrolyte fuel cell according to Modification 3 of Example 2.

FIG. 10 is a plan view showing a concavo-convex shape of a power generation layer according to Modification 4 of Example 2.

FIG. 11 is a sectional view showing a polymer electrolyte fuel cell according to Modification 4 of Example 2.

FIG. 12 is a sectional view showing a configuration of a polymer electrolyte fuel cell as a third embodiment;

FIG. 13 is a cross-sectional view showing a configuration of a polymer electrolyte fuel cell as Example 4.

FIG. 14 is a sectional view showing the concept of a normal polymer electrolyte fuel cell.

[Explanation of symbols]

1: power generation layer 2, 2 ': solid polymer electrolyte layer (perfluorosulfonic acid polymer film) 31, 32, 31', 32 ': catalyst layer (porous layer supporting platinum) 41, 42, 41' , 42 ′, 41 ″, 42 ″: electrode layer (porous layer mainly composed of carbon) 51, 52, 51 ′, 52 ′: metal mesh (as shape holder) 10: fuel gas chamber 20: oxidizing Gas chamber 61, 62, 61 ', 62': Separator (as partition member)

Continuing from the front page (72) Inventor Yoshio Miyata 1-1-1, Showa-cho, Kariya-shi, Aichi Pref. Denso Corporation (72) Inventor Koji Fujiki 1-1-1, Showa-cho, Kariya-shi, Aichi Pref.

Claims (7)

[Claims] 1. A film-shaped solid polymer electrolyte layer that transmits predetermined ions, conductive electrode layers provided on both sides of the solid polymer electrolyte layer, and opposing these respective electrode layers. And a partition member forming a fuel gas chamber and an oxidizing gas chamber between these electrode layers, respectively, wherein the solid polymer electrolyte layer and the electrode layer are A polymer electrolyte fuel cell, characterized in that it has a shape holder which is formed in an uneven shape and has rigidity for holding the uneven shape. 2. The apparatus according to claim 1, wherein said shape retainer is integrally joined to at least one surface of said two electrode layers.
The polymer electrolyte fuel cell according to the above. 3. The polymer electrolyte fuel cell according to claim 1, wherein at least one of the two electrode layers includes the shape retainer. 4. The polymer electrolyte fuel cell according to claim 1, wherein said polymer electrolyte layer includes said shape retainer. 5. The solid according to claim 2, wherein said shape retainer is formed of one of a metal net, a metal porous plate, a metal nonwoven paper, and a metal fiber. Polymer fuel cell. 6. The shape retainer according to claim 2, wherein the shape retainer is formed of any one of a resin net, a resin porous plate, a resin nonwoven paper, a resin powder, and a resin fiber. The polymer electrolyte fuel cell according to the above. 7. The irregular shape includes a corrugated plate shape, a three-dimensional corrugated plate shape formed by Miura folding, and a mesh-like irregular shape in which concave portions and convex portions are arranged adjacent to each other in a triangular or quadrangular mesh shape. The polymer electrolyte fuel cell according to claim 1, which is any one of them.