JP6785405B2 - Electrolyte membrane and fuel cell - Google Patents

Description

The present invention relates to an electrolyte membrane and a fuel cell used in a home cogeneration system, a power source for an electric vehicle, a portable power source, and the like.

As a fuel cell that generates electricity by an electrochemical reaction between a fuel gas and an oxidant gas, a fixed polymer fuel cell provided with an electrolyte membrane composed of a polymer is known.

Conventionally, an electrolyte membrane composed of a polymer is a carbon material in which a first electrolyte layer made of a fluorine-based polymer film having a sulfonic acid group and platinum are supported as a catalyst on the fluorine-based polymer film having a sulfonic acid group. It is configured by joining a second electrolyte layer containing.

Further, in this type of fuel cell, a catalyst layer and a gas diffusion layer are arranged on both main surfaces of an electrolyte membrane having the above-described configuration, and a gas for supplying a fuel gas as a reaction gas and an oxidizing agent gas to the outside thereof. It has a configuration in which a separator provided with a supply groove is arranged (see, for example, Patent Document 1).

FIG. 9 is a configuration diagram showing a conventional electrolyte membrane and a fuel cell described in Patent Document 1 and a unit battery incorporated in the fuel cell.

As shown in FIG. 9A, the electrolyte membrane 90 includes a first electrolyte layer 90a made of a perfluoroalkyl sulfonic acid-based polymer film having a sulfonic acid group as a hydrogen ion exchange group, and the electrolyte film 90 as a hydrogen ion exchange group. The configuration is such that a second electrolyte layer 90b is bonded to a second electrolyte layer 90b containing a carbon material 90d supporting platinum 90c and having a perfluoroalkyl sulfonic acid-based polymer film having a sulfonic acid group as a main component.

Further, as shown in FIG. 9B, the fuel cell 91 has a configuration in which a laminated body in which a plurality of unit batteries 92 are stacked is sandwiched between end plates 93 arranged on both outer sides of the laminated body of the unit batteries 92. .. As shown in FIG. 9C, the unit battery 92 includes an electrolyte membrane-electrode assembly and a pair of separators arranged on both outer sides of the electrolyte membrane-electrode assembly.

The electrolyte membrane-electrode junction is an anode arranged in contact with the electrolyte membrane 90 having the above structure, the anode catalyst layer 94 and the cathode catalyst layer 95 formed on both main surfaces of the electrolyte membrane 90, respectively, and the anode catalyst layer 94. A gas diffusion layer 96 and a cathode gas diffusion layer 97 arranged in contact with the cathode catalyst layer 95 are provided. The anode is composed of the anode catalyst layer 94 and the anode gas diffusion layer 96, and the cathode is composed of the cathode catalyst layer 95 and the cathode gas diffusion layer 97.

The pair of separators arranged on both outer sides of the electrolyte membrane-electrode assembly are an anode separator 98 provided with a fuel gas supply groove for supplying fuel gas to the anode catalyst layer 94, and an oxidant gas in the cathode catalyst layer 95. The cathode separator 99 is provided with an oxidant gas supply groove for supplying the above.

In the fuel cell 91 having the above configuration, when the fuel gas and the oxidant gas as reaction gases are supplied to the fuel gas supply groove of the anode separator 98 and the oxidant gas supply groove of the cathode separator 99, the anode of the unit battery 92 may be used. The electrochemical reaction represented by the formula (1) proceeds, and at the cathode, the electrochemical reaction represented by the formula (2) proceeds, and an electromotive force is generated between the anode and the cathode electrodes.

_{^{Anode: 2H 2 → 4H + + 4e}} - ··· (1)
^{_{Cathode: O 2 + 4H + + 4e}} - → 2H 2 O ··· (2)
At the anode, as shown in the formula (1), hydrogen in the supplied fuel gas is dissociated into hydrogen ions and electrons. At that time, hydrogen ions pass through the electrolyte membrane 90, and electrons move to the cathode through an external circuit.

On the other hand, at the cathode, as shown in the formula (2), oxygen in the supplied oxidant gas reacts with the above-mentioned hydrogen ions and electrons to generate water. At this time, the electrons passing through the external circuit become an electric current, and electric power can be supplied.

The water generated by the reactions of the formulas (1) and (2) is discharged to the outside of the fuel cell 91 together with the reaction gas not consumed by the fuel cell 91.

Here, the electrolyte membrane 90 exhibits good hydrogen ion conductivity when it contains water, but has a property that the hydrogen ion conductivity is remarkably lowered when it is dry. Therefore, it is necessary to keep the electrolyte membrane 90 in a wet state.

When the water content of the electrolyte membrane 90 is increased, the reaction gas easily permeates the electrolyte membrane 90, and the amount of the reaction gas permeated to the counter electrode increases. Since the permeation of the reaction gas through the electrolyte membrane 90 causes a decrease in the battery voltage of the fuel cell 91, it is necessary to prevent the permeation of the reaction gas through the electrolyte membrane 90.

Therefore, in the conventional electrolyte membrane 90 having the above-described configuration, hydrogen permeated from the anode and oxygen permeated from the cathode on the platinum 90c supported on the carbon material 90d contained in the second electrolyte layer 90b. By reacting with and consuming water, the permeation of the reaction gas through the electrolyte membrane 90 is suppressed.

Japanese Unexamined Patent Publication No. 2005-149859

However, in the above-mentioned conventional configuration, in order to suppress the permeation of the reaction gas, it is necessary to disperse a large amount of catalyst in the second electrolyte layer 90b in order to increase the amount of catalyst in the second electrolyte layer 90b to a certain concentration or more. There is a problem that when a large amount of catalyst is dispersed in the second electrolyte layer 90b, the electrical insulating property of the electrolyte film 90 is lowered, an electrical short circuit occurs, and the battery voltage of the fuel cell 91 is lowered.

Further, since the fuel gas and the oxidant gas react inside the electrolyte membrane 90, there is a problem that the consumption of hydrogen increases and the deterioration of the electrolyte membrane 90 is promoted by the heat of reaction.

The present invention solves the above-mentioned conventional problems, suppresses the permeation of the reaction gas through the electrolyte membrane, suppresses a decrease in the battery voltage of the fuel cell and aged deterioration of the electrolyte membrane, and achieves a high battery voltage. An object of the present invention is to provide a fuel cell having excellent durability that can be maintained for a long period of time.

In order to solve the above-mentioned conventional problems, the electrolyte membrane of the present invention is an electrolyte membrane obtained by rubbing a membrane made of a polymer having hydrogen ion conductivity and a salt substitution rate of less than 1%. This is an electrolyte membrane having alignment layers in which the main chains of the polymer are oriented in a plurality of directions substantially parallel to the main surface of the electrolyte membrane only on the surfaces of both main surfaces of the electrolyte membrane.

As a result, in the alignment layer of the electrolyte membrane, the interaction between the molecular chains of the polymers constituting the electrolyte membrane is increased and the free volume is reduced, so that the gas blocking property of the electrolyte membrane is improved. The permeation amount of the reaction gas through the membrane can be reduced.

Further, the fuel cell of the present invention is a fuel cell having an anode and a cathode arranged on both main surfaces with the electrolyte membrane according to the present invention described above interposed therebetween.

As a result, since the electrolyte membrane has excellent gas blocking properties, it is possible to prevent the reaction gas supplied to the fuel cell from penetrating the electrolyte membrane and reacting directly, thereby preventing a decrease in the battery voltage of the fuel cell and also. It is possible to prevent the electrolyte membrane from deteriorating over time.

Since the electrolyte membrane of the present invention is excellent in gas blocking property, the amount of the reaction gas permeated through the electrolyte membrane can be significantly reduced. Further, since the fuel cell of the present invention uses an electrolyte membrane having excellent gas blocking property, the permeation amount of the reaction gas through the electrolyte membrane can be remarkably reduced, and a high battery voltage can be maintained for a long period of time. Can be maintained.

(A) Structural diagram showing the outline of the electrolyte membrane in the first embodiment of the present invention (b) The structural drawing showing the outline of the unit battery incorporated in the fuel cell according to the first embodiment of the present invention. Schematic diagram showing a method for producing an electrolyte membrane having an orientation layer according to the first embodiment of the present invention. (A) Structural diagram showing the outline of the electrolyte membrane in the second embodiment of the present invention (b) The structural drawing showing the outline of the unit battery incorporated in the fuel cell according to the second embodiment of the present invention. Schematic diagram showing a method for producing an electrolyte membrane having an orientation layer according to the second embodiment of the present invention. (A) Configuration diagram showing an outline of the electrolyte membrane in the third embodiment of the present invention (b) Configuration diagram showing an outline of a unit battery incorporated in the fuel cell according to the third embodiment of the present invention. Schematic diagram showing a method for producing an electrolyte membrane having an orientation layer according to the third embodiment of the present invention. (A) Structural diagram showing the outline of the electrolyte membrane in the fourth embodiment of the present invention (b) The structural drawing showing the outline of the unit battery incorporated in the fuel cell according to the fourth embodiment of the present invention. The schematic diagram which shows the manufacturing method of the electrolyte membrane which has an alignment layer in Embodiment 4 of this invention. (A) Configuration diagram showing the outline of the conventional electrolyte membrane (b) Configuration diagram showing the outline of the conventional fuel cell (c) Configuration diagram showing the outline of the unit battery incorporated in the conventional fuel cell

The first invention is an electrolyte membrane containing a polymer, which has an alignment layer in which the main chain of the polymer is oriented in a direction substantially parallel to the main surface of the electrolyte membrane.

With this configuration, in the alignment layer of the electrolyte membrane, the interaction between the molecular chains of the polymers constituting the electrolyte membrane is increased and the free volume is reduced, so that the gas blocking property of the electrolyte membrane is improved, so that the electrolyte membrane is improved. The permeation amount of the reaction gas via the above can be reduced.

The second invention is, in particular, an electrolyte membrane in which the orientation layer of the first invention is an alignment layer in which the main chain of the polymer is oriented in a plurality of directions substantially parallel to the main surface of the electrolyte membrane.

With this configuration, in the alignment layer of the electrolyte membrane, the free volume of the polymer constituting the electrolyte membrane is further reduced, and the gas blocking property of the electrolyte membrane is significantly improved, so that the amount of reaction gas permeated through the electrolyte membrane can be reduced. It can be significantly reduced.

The third invention is, in particular, an electrolyte membrane in which the polymer of the first or second invention is a polymer having hydrogen ion conductivity.

With this configuration, particularly when it is used for an electrolyte membrane of a fuel cell using hydrogen as a fuel, it exhibits good hydrogen ion conductivity, so that the battery voltage of the fuel cell can be increased.

A fourth invention is a fuel cell having an electrolyte membrane according to any one of the first to third inventions, and an anode and a cathode arranged on both main surfaces with the electrolyte membrane interposed therebetween.

With this configuration, the amount of the reaction gas supplied to the fuel cell permeated through the electrolyte membrane is reduced, and the reaction gas can be prevented from reacting directly. Therefore, it is possible to prevent a decrease in the battery voltage of the fuel cell, and also , It is possible to prevent the deterioration of the electrolyte membrane over time.

The fifth invention is, in particular, a fuel cell in which the anode of the fourth invention is arranged in contact with the alignment layer of the electrolyte membrane.

With this configuration, even when a fuel gas such as hydrogen having a small molecular diameter and high permeability is used, the permeation amount of the fuel gas through the electrolyte membrane is reduced, and the reaction gas is prevented from directly reacting. Therefore, it is possible to prevent a decrease in the battery voltage of the fuel cell and prevent aged deterioration of the electrolyte membrane.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to this embodiment.

(Embodiment 1)
FIG. 1A is a configuration diagram showing an outline of the electrolyte membrane according to the first embodiment of the present invention, and FIG. 1B is an outline of a unit battery incorporated in the fuel cell according to the first embodiment of the present invention. It is a block diagram which shows. Further, FIG. 2 is a schematic view showing a method for producing an electrolyte membrane having an orientation layer according to the first embodiment of the present invention.

In FIG. 1A, the electrolyte membrane 10 includes an orientation layer 10a in which the main chains of the polymers constituting the electrolyte membrane 10 are regularly oriented in a certain direction, and the main chains of the polymers constituting the electrolyte membrane 10. It is composed of randomly arranged non-oriented layers 10b.

Further, in FIG. 1B, the unit battery 11 incorporated in the fuel cell includes an electrolyte membrane-electrode assembly and a pair of separators arranged on both outer sides of the electrolyte membrane-electrode assembly.

The electrolyte membrane-electrode junction includes an electrolyte membrane 10, an anode catalyst layer 12 formed on one main surface of the electrolyte membrane 10, a cathode catalyst layer 13 formed on the other main surface of the electrolyte membrane 10, and an anode. The anode gas diffusion layer 14 and the cathode gas diffusion layer 15 are provided outside the catalyst layer 12 and the cathode catalyst layer 13.

The anode catalyst layer 12 and the anode gas diffusion layer 14 form an anode, and the cathode catalyst layer 13 and the cathode gas diffusion layer 15 form a cathode.

The pair of separators arranged on both outer sides of the electrolyte membrane-electrode assembly are the anode separator 16 arranged on the outside of the anode gas diffusion layer 14 and the cathode separator 17 arranged on the outside of the cathode gas diffusion layer 15. ..

The electrolyte membrane 10 and the unit battery 11 configured as described above will be specifically described below with reference to the constituent materials thereof.

The electrolyte membrane 10 is made of a polymer having hydrogen ion conductivity, and specifically, is made of a perfluoroalkylsulfonic acid-based polymer having a sulfonic acid group as a hydrogen ion exchange group.

The anode catalyst layer 12 and the cathode catalyst layer 13 are composed of a catalyst powder composed of carbon particles supporting platinum or a platinum alloy and an electrolyte.

The anode gas diffusion layer 14 and the cathode gas diffusion layer 15 are made of conductive carbon paper having both gas air permeability and electron conductivity.

The anode separator 16 and the cathode separator 17 are made of a graphite plate impregnated with a resin, and a gas supply groove for passing a reaction gas is formed on the surface thereof.

Next, a method for producing the electrolyte membrane 10 having the alignment layer 10a, which is a point of the invention of the electrolyte membrane 10 and the fuel cell according to the present embodiment, will be described with reference to FIG. In FIG. 2, the same reference numerals are given to the same components as those in FIG.

As shown in FIG. 2, the electrolyte membrane 10 having the alignment layer 10a is produced by the following procedure. First, an electrolyte membrane 23 having no alignment layer is prepared and fixed to an adsorption plate 20 provided with an adsorption mechanism (FIG. 2A).

Next, in a state where the roller 22 to which the cloth 21 is attached is pushed into the electrolyte membrane 23 by a predetermined pushing amount, it is rotated at a predetermined rotation speed, and at the same time, the adsorption plate 20 to which the electrolyte membrane 23 is fixed is predetermined in a fixed direction. The surface of the electrolyte membrane 23 is rubbed by moving at the speed of (FIG. 2 (b)).

By this operation, an alignment layer 10a in which the main chain of the polymer constituting the electrolyte membrane 23 is oriented in one direction (direction parallel to the main surface) is formed on one main surface of the electrolyte membrane 23 (hereinafter, electrolyte). The axis indicating the direction in which the main chain of the polymer constituting the membrane is oriented is called the orientation axis).

Here, the pushing amount is the position where the bristles of the cloth 21 attached to the roller 22 first come into contact with the surface of the electrolyte membrane 23 when the position of the roller 22 is changed with respect to the surface of the electrolyte membrane 23. Is the origin, and the amount of fluctuation in which the roller 22 is pushed toward the electrolyte membrane 23 from the origin.

By the above series of operations, the main chain of the polymer constituting the electrolyte membrane 23 is oriented in one direction (direction parallel to the main surface) on one main surface of the electrolyte membrane 23 having no alignment layer. By forming the alignment layer 10a, an electrolyte membrane 10 having an alignment layer 10a in which one alignment axis substantially parallel to the main surface is formed on one main surface can be obtained.

As described above, in the present embodiment, the electrolyte membrane 10 has an alignment layer 10a in which the main chain of the polymer constituting the electrolyte membrane 10 is oriented in one direction (direction parallel to the main surface). As a result, in the alignment layer 10a, the interaction between the molecular chains of the polymer is increased, the free volume is reduced, and the permeation amount of the reaction gas through the electrolyte membrane 10 can be reduced.

Further, in the present embodiment, by using the electrolyte membrane 10 having an alignment layer 10a and excellent in blocking property of the reaction gas, it is possible to provide a fuel cell in which the permeation amount of the reaction gas is reduced.

In such a fuel cell, the permeation amount of the reaction gas through the electrolyte membrane 10 is reduced, and the reaction of the reaction gas inside the electrolyte membrane 10 is suppressed to suppress the deterioration of the electrolyte membrane 10 over time. Therefore, it is possible to suppress a decrease in the battery voltage of the fuel cell.

Hereinafter, the electrolyte membrane and the fuel cell according to the present embodiment will be described in more detail based on specific examples, but the present invention is not necessarily limited to the contents of the specific raw materials and the like used below. is not. The method for evaluating various physical properties of the electrolyte membrane and the method for evaluating the battery performance of the unit battery incorporated in the fuel cell are shown below.

(1) Birefringence and plane orientation coefficient Using a retardation film optical material inspection device (manufactured by Otsuka Electronics Co., Ltd .: model RETS-100), the refractive index nx in the direction of the orientation axis of the electrolyte film, and in-plane perpendicular to it. The refractive index ny in the direction and the refractive index nz in the thickness direction were measured, and from the obtained values,
Δn = nx-ny
ΔP = (nx + ny) /2-nz
The birefringence Δn and the plane orientation coefficient ΔP of the electrolyte membrane were calculated by the above formulas.

(2) Amount of hydrogen permeation The electrolyte membrane is fixed to a jig that can supply and discharge gas to both main surfaces of the electrolyte membrane, and hydrogen is supplied to one main surface of the electrolyte membrane and nitrogen is supplied to the other main surface. By quantifying the amount of hydrogen contained in the supplied and discharged nitrogen using a gas analyzer (Shimadzu Seisakusho Co., Ltd .: Model GC-8A), it permeates from the hydrogen supply side to the nitrogen supply side. The amount of hydrogen produced (hereinafter referred to as hydrogen permeation amount Vh) was evaluated.

At this time, both hydrogen and nitrogen were gas in a dry state at room temperature, and the flow rates were both 0.3 L / min.

(3) Battery performance Hydrogen containing 25% carbon dioxide and 50 ppm carbon monoxide flows through the gas supply groove of the anode separator of the unit battery, air flows through the gas supply groove of the cathode separator, the battery temperature is 80 ° C, and fuel is used. The initial battery voltage when the rate is set to 80%, the air utilization rate is 40%, the hydrogen dew point is set to 75 ° C, the air dew point is set to 60 ° C, and continuous power is generated at a current density of 0.2 A / cm ² . The battery voltage was measured after 2000 hours had passed.

(Example 1)
(1) Preparation of Electrolyte Membrane Nafion 112 (manufactured by DuPont Co., Ltd.) was prepared as an electrolyte membrane having no alignment layer, and was adsorbed and fixed on an adsorption plate.

Subsequently, a roller having a cloth (manufactured by Naganuma Gauge Mfg. Co., Ltd., product type: CFT055) attached to the surface is pushed into one main surface of the Nafion 112 with a pushing amount of 1 mm, and is rotated at a rotation speed of 10s ^-1 . Then, the adsorption plate is moved in one direction at a speed of 5 mm / s, and one main surface of the Nafion 112 is rubbed in one direction, and the one main surface of the Nafion 112 has an alignment layer having one alignment axis. Nafion 112 (hereinafter referred to as electrolyte membrane A) was prepared.

When the birefringence Δn, the surface orientation coefficient ΔP, and the hydrogen permeation amount Vh of the electrolyte membrane A thus produced were evaluated by the above-mentioned evaluation method, the birefringence Δn, the surface orientation coefficient ΔP, and the hydrogen permeation amount Vh of the electrolyte membrane A were (1). As shown in Table 1), the electrolyte membrane A has a birefringence Δn and a plane orientation coefficient ΔP showing large values, and the main chain of the polymer is regularly oriented in a certain direction, and the electrolyte. Membrane A had a small amount of hydrogen permeation and showed good hydrogen blocking property.

(2) Preparation of unit battery A unit battery using the electrolyte membrane A was prepared by the following procedure.

a. Preparation of anode catalyst 15 parts by weight of carbon powder carrying platinum and ruthenium as catalyst powder (manufactured by Tanaka Kikinzoku Co., Ltd., product number: TEC66E50), 10% dispersion of Nafion as electrolyte (manufactured by Sigma Aldrich, product number: 527114) 50 parts by weight, 20 parts by weight of pure water and 65 parts by weight of ethanol were collected in a container, and a disperser (manufactured by Seiwa Giken Co., Ltd., product name: RS-05W) and an ultrasonic homogenizer (Nippon Seiki Co., Ltd.) were collected. Using Mfg. Co., Ltd., product name: US-150E), the mixture was kneaded at room temperature for 2 hours to prepare a catalyst composition (hereinafter referred to as catalyst composition a).

b. Preparation of cathode catalyst 15 parts by weight of platinum-supported carbon powder (manufactured by Tanaka Kikinzoku Co., Ltd., product number: TEC10E50E) as catalyst powder, 50 parts by weight of Nafion 10% dispersion (manufactured by Sigma Aldrich, product number: 527114) as electrolyte 20 parts by weight of pure water and 65 parts by weight of ethanol were collected in a container as a dispersion medium, and a disperser (manufactured by Seiwa Giken Co., Ltd., product name: RS-05W) and an ultrasonic homogenizer (Nippon Seiki Seisakusho Co., Ltd.) Using (product name: US-150E), the mixture was kneaded at room temperature for 2 hours to prepare a catalyst composition (hereinafter referred to as catalyst composition b).

c. Fabrication of Electrolyte Membrane-Electrolyte Assembly A catalyst composition a is placed on one main surface of the electrolyte membrane A, and a catalyst composition b is placed on the other main surface of a screen printing machine (manufactured by Neurongue Precision Industry Co., Ltd.). Name: DP-320) was applied by the screen printing method.

Subsequently, the electrolyte membrane A coated with the catalyst compositions a and b described above is left in a thermostat at 80 ° C. (manufactured by Yamato Scientific Co., Ltd., model number: DKM300) for 1 hour to cause the catalyst compositions a and b. After removing the dispersion medium from the above by heating and drying, the mixture was left at room temperature for 2 hours to form an anode catalyst layer and a cathode catalyst layer on both main surfaces of the electrolyte membrane A to prepare an electrolyte membrane-catalyst layer conjugate.

d. Manufacture of unit battery First, a dispersion of acetylene black and polytetrafluoroethylene on carbon paper (manufactured by Toray Industries, Inc., product name: TGP-H-120) (manufactured by Daikin Industries, Ltd., product name: D-1) A mixture of pure water and pure water was applied and heated at 350 ° C. for 2 hours to prepare a gas diffusion layer.

Subsequently, the above-mentioned gas diffusion layers are arranged on both main surfaces of the electrolyte membrane-catalyst layer assembly prepared by the above procedure to form an electrolyte membrane-electrode assembly, and then the electrolyte membrane-electrode assembly and the gas diffusion layer. A gasket made of silicone resin (manufactured by Kureha Electrolyte Co., Ltd., product number: SB50NJP) is bonded to the outer periphery of the surface, and a separator composed of a resin-impregnated graphite plate having a gas supply groove formed on the surface is attached to the outside of both gas diffusion layers. A unit battery (hereinafter referred to as unit battery A) was produced.

When the battery performance of the unit battery A thus produced was evaluated by the above-mentioned evaluation method, the battery voltage of the unit battery A was as shown in (Table 1), and the unit battery A showed a high battery voltage at the initial stage and was 2000. There was no decrease in battery voltage even after the lapse of time, showing excellent durability.

(Embodiment 2)
FIG. 3A is a configuration diagram showing an outline of the electrolyte membrane according to the second embodiment of the present invention, and FIG. 3B is an outline of a unit battery incorporated in the fuel cell according to the second embodiment of the present invention. It is a block diagram which shows. Further, FIG. 4 is a schematic view showing a method for producing an electrolyte membrane having an orientation layer according to the second embodiment of the present invention.

In FIG. 3A, the electrolyte membrane 30 of the present embodiment is different from the electrolyte membrane 10 of the first embodiment in that the alignment layers 30a are provided on both main surfaces of the electrolyte membrane 30. Further, in FIG. 3B, the unit battery 31 incorporated in the fuel cell of the present embodiment is different from the unit battery 11 of the first embodiment in that the electrolyte membrane 30 having the alignment layers 30a on both main surfaces is used. Is different.

Hereinafter, the configuration of the electrolyte membrane and the unit battery incorporated in the fuel cell according to the present embodiment will be described with reference to FIG. In FIG. 3, the same components as those in FIG. 1 are given the same reference numerals, and duplicate description will be omitted.

In FIG. 3A, the electrolyte membrane 30 includes an orientation layer 30a in which the main chains of the polymers constituting the electrolyte membrane 30 are regularly oriented in a certain direction, and the main chains of the polymers constituting the electrolyte membrane 30. It is composed of randomly arranged non-oriented layers 30b.

Here, the electrolyte membrane 30 is made of a polymer having hydrogen ion conductivity, and specifically, is made of a perfluoroalkylsulfonic acid-based polymer having a sulfonic acid group as a hydrogen ion exchange group.

Further, in FIG. 3B, the unit battery 31 to be incorporated in the fuel cell includes a electrolyte membrane-electrode assembly and a pair of separators arranged on both outer sides of the electrolyte membrane-electrode assembly.

The electrolyte membrane-electrode junction includes an electrolyte membrane 30, an anode catalyst layer 12 formed on one main surface of the electrolyte membrane 30, a cathode catalyst layer 13 formed on the other main surface of the electrolyte membrane 30, and an anode. The anode gas diffusion layer 14 and the cathode gas diffusion layer 15 are provided outside the catalyst layer 12 and the cathode catalyst layer 13.

The anode catalyst layer 12 and the anode gas diffusion layer 14 form an anode, and the cathode catalyst layer 13 and the cathode gas diffusion layer 15 form a cathode.

The pair of separators arranged on both outer sides of the electrolyte membrane-electrode assembly are the anode separator 16 arranged on the outside of the anode gas diffusion layer 14 and the cathode separator 17 arranged on the outside of the cathode gas diffusion layer 15. ..

Next, a method for producing the electrolyte membrane 30 having the alignment layer 30a, which is a point of the invention of the electrolyte membrane 30 and the fuel cell according to the present embodiment, will be described with reference to FIG. In FIG. 4, the same components as those in FIGS. 2 and 3 are given the same reference numerals.

As shown in FIG. 4, the electrolyte membrane 30 having the alignment layer 30a is produced by the following procedure. First, an electrolyte membrane 23 having no alignment layer is prepared and fixed to an adsorption plate 20 provided with an adsorption mechanism (FIG. 4A).

Next, in a state where the roller 22 to which the cloth 21 is attached is pushed into one main surface of the electrolyte membrane 23 by a predetermined pushing amount, it is rotated at a predetermined rotation speed, and at the same time, the adsorption plate 20 to which the electrolyte membrane 23 is fixed is moved. By moving in a fixed direction at a predetermined speed, one surface of the electrolyte membrane 23 is rubbed (FIG. 4 (b)).

By this operation, an alignment layer 30a in which the main chain of the polymer constituting the electrolyte membrane is oriented in one direction (direction parallel to the main surface) is formed on one main surface of the electrolyte membrane 23 (FIG. 4 (c). )).

Subsequently, the electrolyte membrane 23 is turned inside out and fixed to the adsorption plate 20 with the other main surface of the electrolyte membrane 23 facing upward, and then the roller 22 to which the cloth 21 is attached is pushed into the other main surface of the electrolyte membrane 23 by a predetermined amount. In the state of being pushed in, the electrolyte membrane 23 is rotated at a predetermined rotation speed, and at the same time, the adsorption plate 20 to which the electrolyte membrane 23 is fixed is moved in a fixed direction at a predetermined speed to rub the other main surface of the electrolyte membrane 23 (FIG. 4 (d)).

By this operation, an alignment layer 30a in which the main chains of the polymers constituting the electrolyte membrane are oriented in one direction (direction parallel to the main surface) is also formed on the other main surface of the electrolyte membrane 23 (FIG. 4 (FIG. 4). e)).

Here, the pushing amount is the position where the bristles of the cloth 21 attached to the roller 22 first come into contact with the surface of the electrolyte membrane 23 when the position of the roller 22 is changed with respect to the surface of the electrolyte membrane 23. Is the origin, and the amount of fluctuation in which the roller 22 is pushed toward the electrolyte membrane 23 from the origin.

By the above series of operations, an alignment layer 30a in which the main chains of the polymers constituting the electrolyte membrane 23 are oriented in one direction (parallel to the main surface) is formed on both main surfaces of the electrolyte membrane 23. On both main surfaces, an electrolyte membrane 30 having an alignment layer 30a in which one alignment axis substantially parallel to the main surfaces is formed can be obtained.

As described above, in the present embodiment, both main surfaces of the alignment layer 30a in which the main chain of the polymer constituting the electrolyte membrane 30 is oriented in one direction (direction parallel to the main surface). In the alignment layer 30a, the interaction between the molecular chains of the polymer is increased, the free volume is reduced, and the permeation amount of the reaction gas through the electrolyte membrane 30 can be reduced.

Further, in the present embodiment, by using the electrolyte membrane 30 which has an alignment layer 30a and is excellent in blocking reaction gas, it is possible to provide a fuel cell in which the permeation amount of the reaction gas is reduced.

In such a fuel cell, the permeation amount of the reaction gas through the electrolyte membrane 30 is reduced, and the reaction of the reaction gas inside the electrolyte membrane 30 is suppressed to suppress the deterioration of the electrolyte membrane 30 over time. Therefore, it is possible to suppress a decrease in the battery voltage of the fuel cell.

Hereinafter, the electrolyte membrane and the fuel cell according to the present embodiment will be described in more detail based on specific examples, but the present invention is not necessarily limited to the contents of the specific raw materials and the like used below. is not.

(Example 2)
(1) Preparation of Electrolyte Membrane Nafion 112 (manufactured by DuPont Co., Ltd.) was prepared as an electrolyte membrane having no alignment layer, and was adsorbed and fixed on an adsorption plate.

Subsequently, a roller having a cloth (manufactured by Naganuma Gauge Mfg. Co., Ltd., product type: CFT055) attached to the surface is pushed into one main surface of the Nafion 112 with a pushing amount of 1 mm, and is rotated at a rotation speed of 10 s ^-1 . Then, the suction plate is moved in one direction at a speed of 5 mm / s, and Nafion 1
One main surface of 12 was rubbed in one direction to form an alignment layer having one orientation axis on one main surface of Nafion 112.

Next, the Nafion 112 is turned over and fixed to the suction plate so that the other main surface of the Nafion 112 faces upward, and then the pushing amount and the number of rotations of the rollers and the suction plate are determined by using the same roller as the above-mentioned roller. The movement speed is the same as each of the above-mentioned conditions, and the other main surface of the Nafion 112 is rubbed in one direction, and the Nafion 112 having one alignment layer on both main surfaces (hereinafter referred to as electrolyte membrane B). Was produced.

When the birefringence Δn, the plane orientation coefficient ΔP, and the hydrogen permeation amount Vh of the electrolyte membrane B thus produced were evaluated by the same evaluation method as the above-mentioned evaluation method, the birefringence Δn, the plane orientation coefficient ΔP, and the hydrogen permeation of the electrolyte membrane B were evaluated. The amount Vh is as shown in (Table 1), the electrolyte membrane B shows large values of birefringence Δn and plane orientation coefficient ΔP, and the main chain of the polymer is regularly oriented in a certain direction. In addition, the electrolyte membrane B had a small amount of hydrogen permeation and showed good hydrogen blocking property.

(2) Preparation of Unit Battery Using the electrolyte membrane B, a unit battery (hereinafter referred to as unit battery B) was prepared by the same procedure as that described in Example 1 (2) described above.

When the battery performance of the unit battery B thus produced was evaluated by the same evaluation method as the above-mentioned evaluation method, the battery voltage of the unit battery B is as shown in (Table 1), and the unit battery B has a high battery voltage at the initial stage. The battery voltage did not decrease even after 2000 hours, and the durability was excellent.

(Embodiment 3)
FIG. 5A is a configuration diagram showing an outline of the electrolyte membrane according to the third embodiment of the present invention, and FIG. 5B is an outline of a unit battery incorporated in the fuel cell according to the third embodiment of the present invention. It is a block diagram which shows. Further, FIG. 6 is a schematic view showing a method for producing an electrolyte membrane having an orientation layer according to the third embodiment of the present invention.

In FIG. 5A, the electrolyte membrane 50 of the present embodiment is different from the electrolyte membrane 30 of the second embodiment in that the alignment layer 50a has two orientation axes. Further, in FIG. 5B, the unit battery 51 incorporated in the fuel cell of the present embodiment uses an electrolyte membrane 50 having two orientation layers 50a on both main surfaces. It is different from the unit battery 30 of 2.

Hereinafter, the configuration of the electrolyte membrane and the unit battery incorporated in the fuel cell according to the present embodiment will be described with reference to FIG. In FIG. 5, the same components as those in FIG. 1 are given the same reference numerals, and duplicate description will be omitted.

In FIG. 5A, the electrolyte membrane 50 includes an orientation layer 50a in which the main chains of the polymers constituting the electrolyte membrane 50 are regularly oriented in a certain direction, and the main chains of the polymers constituting the electrolyte membrane 50. It is composed of randomly arranged non-oriented layers 50b.

Here, the electrolyte membrane 50 is composed of a polymer having hydrogen ion conductivity, and specifically, is composed of a perfluoroalkylsulfonic acid-based polymer having a sulfonic acid group as a hydrogen ion exchange group.

Further, in FIG. 5B, the unit battery 51 to be incorporated in the fuel cell includes an electrolyte membrane-electrode assembly and a pair of separators arranged on both outer sides of the electrolyte membrane-electrode assembly.

The electrolyte membrane-electrode junction includes an electrolyte membrane 50, an anode catalyst layer 12 formed on one main surface of the electrolyte membrane 50, a cathode catalyst layer 13 formed on the other main surface of the electrolyte membrane 10, and an anode. The anode gas diffusion layer 14 and the cathode gas diffusion layer 15 are provided outside the catalyst layer 12 and the cathode catalyst layer 13.

The anode catalyst layer 12 and the anode gas diffusion layer 14 form an anode, and the cathode catalyst layer 13 and the cathode gas diffusion layer 15 form a cathode.

The pair of separators arranged on both outer sides of the electrolyte membrane-electrode assembly are the anode separator 16 arranged on the outside of the anode gas diffusion layer 14 and the cathode separator 17 arranged on the outside of the cathode gas diffusion layer 15. ..

Next, a method for producing the electrolyte membrane 50 having the alignment layer 50a, which is a point of the invention of the electrolyte membrane 50 and the fuel cell according to the present embodiment, will be described with reference to FIG. In FIG. 6, the same components as those in FIGS. 2 and 5 are given the same reference numerals.

As shown in FIG. 6, the electrolyte membrane 50 having the alignment layer 50a is produced by the following procedure. First, an electrolyte membrane 23 having no alignment layer is prepared and fixed to an adsorption plate 20 provided with an adsorption mechanism (FIG. 6A).

Next, in a state where the roller 22 to which the cloth 21 is attached is pushed into one main surface of the electrolyte membrane 23 by a predetermined pushing amount, the roller 22 is rotated at a predetermined rotation speed, and at the same time, the adsorption plate 20 to which the electrolyte membrane 23 is fixed is moved. By moving in a fixed direction at a predetermined speed, one surface of the electrolyte membrane 23 is rubbed (FIG. 6 (b)).

By this operation, a first orientation axis is formed on one main surface of the electrolyte membrane 23 in which the main chain of the polymer constituting the electrolyte membrane 23 is oriented in one direction (direction parallel to the main surface) (FIG. 6 (c)).

Next, the electrolyte is placed on the adsorption plate 20 so that the main surface on which the first alignment axis is formed faces upward and the moving direction of the adsorption plate 20 is substantially perpendicular to the direction of the first alignment axis. A suction plate in which the membrane 23 is fixed and the roller 22 to which the cloth 21 is attached is pushed into one main surface of the electrolyte membrane 23 by a predetermined pushing amount and rotated at a predetermined rotation speed, and at the same time, the electrolyte membrane 23 is fixed. By moving 20 in a fixed direction at a predetermined speed, one main surface of the electrolyte membrane 23 is rubbed in a direction substantially perpendicular to the direction of the first orientation axis (FIG. 6 (d)).

By this operation, a second orientation axis is formed on one main surface of the electrolyte membrane 23, and an orientation layer 50a having two orientation axes is formed on one main surface of the electrolyte membrane 23 (FIG. 6 (e)). ..

Subsequently, the electrolyte membrane 23 is turned over, and the same operation as in FIGS. 6 (a) to 6 (e) is repeated on the other main surface of the electrolyte membrane 23, and a third orientation axis is formed on the other main surface of the electrolyte membrane 23. A fourth alignment axis is formed, and an alignment layer 50a having two alignment axes is also formed on the other main surface of the electrolyte membrane 23.

Here, the pushing amount is the position where the bristles of the cloth 21 attached to the roller 22 first come into contact with the surface of the electrolyte membrane 23 when the position of the roller 22 is changed with respect to the surface of the electrolyte membrane 23. Is the origin, and the amount of fluctuation in which the roller 22 is pushed toward the electrolyte membrane 23 from the origin.

By forming the alignment layer 50a in which the main chains of the polymers constituting the electrolyte membrane 23 are oriented in two directions on both main surfaces of the electrolyte membrane 23 by the above series of operations, the main surfaces on both main surfaces are formed. An electrolyte membrane 50 having an alignment layer 50a formed with two orientation axes substantially parallel to the above can be obtained.

As described above, in the present embodiment, the electrolyte membrane 50 has an orientation layer 50a on both main surfaces in which the main chains of the polymers constituting the electrolyte membrane 50 are oriented in two directions substantially parallel to the main surface. As a result, in the alignment layer 50a, the interaction between the molecular chains of the polymer is increased, the free volume is reduced, and the permeation amount of the reaction gas through the electrolyte membrane 50 can be reduced.

Further, in the present embodiment, a fuel cell in which the permeation amount of the reaction gas is reduced is provided by using the electrolyte membrane 50 having the alignment layers 50a on both main surfaces and having excellent blocking property of the reaction gas. Can be done.

In such a fuel cell, the permeation amount of the reaction gas through the electrolyte membrane 50 is reduced, and the reaction of the reaction gas inside the electrolyte membrane 50 is suppressed to suppress the deterioration of the electrolyte membrane 50 over time. Therefore, it is possible to suppress a decrease in the battery voltage of the fuel cell.

Hereinafter, the electrolyte membrane and the fuel cell according to the present embodiment will be described in more detail based on specific examples, but the present invention is not necessarily limited to the contents of the specific raw materials and the like used below. is not.

(Example 3)
(1) Preparation of Electrolyte Membrane Nafion 112 (manufactured by DuPont Co., Ltd.) was prepared as an electrolyte membrane having no alignment layer, and was adsorbed and fixed on an adsorption plate.

Subsequently, a roller having a cloth (manufactured by Naganuma Gauge Mfg. Co., Ltd., product type: CFT055) attached to the surface is pushed into one main surface of the Nafion 112 with a pushing amount of 1 mm, and is rotated at a rotation speed of 10 s ^-1 . Then, the suction plate was moved in one direction at a speed of 5 mm / s, and one main surface of the Nafion 112 was rubbed in one direction to form a first orientation axis on one main surface of the Nafion 112.

Next, using the same roller as the above-mentioned roller, the same main surface as the main surface forming the first orientation axis of the Nafion 112 is rubbed in a direction substantially perpendicular to the first orientation axis, and the Nafion 112 A second orientation axis was formed on one main surface, and an orientation layer having two orientation axes was formed on one main surface of Nafion 112.

Subsequently, the Nafion 112 is turned over and fixed to the suction plate so that the other main surface of the Nafion 112 faces upward, and then the other main surface of the Nafion 112 is unidirectionally used by using the same roller as the above-mentioned roller. After rubbing to form a third alignment axis on the other main surface of the Nafion 112, the same main surface as the main surface on which the third alignment axis was formed was rubbed in a direction substantially perpendicular to the third alignment axis. A fourth orientation axis was formed on the other main surface of the Nafion 112, and an alignment layer having two alignment axes was formed on both main surfaces to prepare a Nafion 112 (hereinafter referred to as electrolyte membrane C).

The amount of pushing of the roller and the number of rotations when forming the second alignment axis, the third alignment axis, and the fourth alignment axis, and the moving speed of the suction plate are each when the first alignment axis is formed. The conditions were the same as the conditions.

When the birefringence Δn, the plane orientation coefficient ΔP, and the hydrogen permeation amount Vh of the electrolyte membrane C thus produced were evaluated by the same evaluation method as the above-mentioned evaluation method, the birefringence Δn, the plane orientation coefficient ΔP, and the hydrogen permeation of the electrolyte membrane C were evaluated. The amount Vh is as shown in (Table 1), the electrolyte membrane C shows a large value of birefringence Δn and a plane orientation coefficient ΔP, and the main chain of the polymer is regularly oriented in a certain direction. In addition, the electrolyte membrane C had a small amount of hydrogen permeation and showed good hydrogen blocking property.

(2) Preparation of Unit Battery Using the electrolyte membrane C, a unit battery (hereinafter referred to as unit battery C) was prepared by the same procedure as that described in Example 1 (2) described above.

When the battery performance of the unit battery C thus produced was evaluated by the same evaluation method as the above-mentioned evaluation method, the battery voltage of the unit battery C is as shown in (Table 1), and the unit battery C has a high battery voltage at the initial stage. The battery voltage did not decrease even after 2000 hours, and the durability was excellent.

(Comparative Example 1)
Nafion 112 (manufactured by DuPont Co., Ltd.) (hereinafter referred to as electrolyte membrane D) was prepared as an electrolyte membrane having no alignment layer, and the birefringence Δn of the electrolyte membrane D was determined by the same evaluation method as the above-mentioned evaluation method. The plane orientation coefficient ΔP and the hydrogen permeation amount Vh were evaluated.

The double refraction Δn, surface orientation coefficient ΔP, and hydrogen permeation amount Vh of the electrolyte membrane D are as shown in (Table 1), and the electrolyte membrane D shows small values of the double refraction Δn and the surface orientation coefficient ΔP. The main chains are randomly arranged, and the electrolyte membrane D has a larger amount of hydrogen permeation and is inferior in hydrogen blocking property as compared with the electrolyte membranes (electrolyte membranes A to C) of Examples 1 to 3. Met.

Next, using the electrolyte membrane D, a unit battery (hereinafter referred to as unit battery D) is produced by the same method as that described in Example 1 (2) described above, and the same evaluation method as the evaluation method described above is used. The battery performance of the unit battery D was evaluated.

The battery voltage of the unit battery D is as shown in (Table 1), and the initial battery voltage of the unit battery D was the same as that of the unit batteries (unit batteries A to C) of Examples 1 to 3, but 2000. After a lapse of time, the battery voltage dropped significantly, and the durability was inferior to that of the unit batteries (unit batteries A to C) of Examples 1 to 3.

The above results are summarized in (Table 1).

電解質膜の水素透過性に関し、本実施例に係る電解質膜（電解質膜Ａ〜Ｃ）は、いずれも水素の透過量が少ないものであった。これは、電解質膜が配向層を有することで、配向層において、電解質膜を構成する高分子の主鎖が一定の方向に配向することにより、高分子の分子鎖間の相互作用が大きくなって自由体積が減少し、水素に対する遮断性が向上したためと考えられる。

Regarding the hydrogen permeability of the electrolyte membrane, all of the electrolyte membranes (electrolyte membranes A to C) according to this example had a small amount of hydrogen permeation. This is because the electrolyte membrane has an alignment layer, and the main chains of the polymer constituting the electrolyte membrane are oriented in a certain direction in the alignment layer, so that the interaction between the molecular chains of the polymer becomes large. It is considered that this is because the free volume is reduced and the blocking property against hydrogen is improved.

On the other hand, the electrolyte membrane (electrolyte membrane D) according to the comparative example had a larger amount of hydrogen permeation than the electrolyte membranes (electrolyte membranes A to C) according to the present example. It is considered that this is because the electrolyte membrane does not have an alignment layer, so that the main chains of the polymers constituting the electrolyte membrane are randomly arranged, the free volume of the polymer is increased, and the blocking property against hydrogen is lowered. Be done.

Further, regarding the battery performance of the unit battery, the battery voltage of the unit batteries (unit batteries A to C) according to the present embodiment did not decrease even after 2000 hours had elapsed. This is because the electrolyte membrane has an orientation layer, which reduces the permeation amount of the reaction gas, so that the reaction of the reaction gas inside the electrolyte membrane is suppressed, and the deterioration of the electrolyte membrane over time can be prevented. It is thought that it was a cause.

On the other hand, the unit battery (unit battery D) according to the comparative example has a significantly reduced battery voltage after 2000 hours, and is inferior in durability to the unit batteries (unit batteries A to C) according to the present embodiment. Met. It is considered that this is because the electrolyte membrane does not have an alignment layer, so that the permeation amount of the reaction gas increases, the reaction gas reacts inside the electrolyte membrane, and the electrolyte membrane deteriorates over time.

From the above hydrogen permeation evaluation test of the electrolyte membrane, it was confirmed that the permeation amount of the reaction gas was reduced in the electrolyte membranes A to C produced in the present embodiment. Further, from the battery performance evaluation test of the unit battery, it was confirmed that the unit batteries A to C produced in the present embodiment show excellent durability without a decrease in the battery voltage.

(Embodiment 4)
FIG. 7A is a configuration diagram showing an outline of the electrolyte membrane according to the fourth embodiment of the present invention, and FIG. 7B is an outline of a unit battery incorporated in the fuel cell according to the fourth embodiment of the present invention. It is a block diagram which shows. Further, FIG. 8 is a schematic view showing a method for producing an electrolyte membrane having an orientation layer according to the fourth embodiment of the present invention.

In FIG. 7A, the electrolyte membrane 70 of the present embodiment is different from the electrolyte membrane 10 of the first embodiment in that the alignment layer 71a is provided inside (intermediate layer) of the electrolyte membrane 70. Further, in FIG. 7B, the unit battery 73 incorporated in the fuel cell of the present embodiment uses the electrolyte membrane 70 having the alignment layer 71a inside (intermediate layer), and is the unit battery of the first embodiment. Different from 10.

Hereinafter, the configurations of the electrolyte membrane 70 and the unit battery incorporated in the fuel cell according to the present embodiment will be described with reference to FIG. 7. In FIG. 7, the same components as those in FIG. 1 are given the same reference numerals, and duplicate description will be omitted.

In FIG. 7A, the electrolyte membrane 70 includes an orientation layer 71a in which the main chains of the polymers constituting the electrolyte membrane 70 are regularly oriented in a certain direction, and the main chains of the polymers constituting the electrolyte membrane 70. It is composed of a first electrolyte membrane 71 having a randomly arranged non-oriented layer 71b and a second electrolyte membrane 72 in which the main chains of the polymers constituting the electrolyte membrane 70 are randomly arranged.

Here, the first electrolyte membrane 71 and the second electrolyte membrane 72 are composed of a polymer having hydrogen ion conductivity, and specifically, a perfluoroalkyl sulfonic acid having a sulfonic acid group as a hydrogen ion exchange group. It is composed of system polymers.

Further, in FIG. 7B, the unit battery 73 to be incorporated in the fuel cell includes an electrolyte membrane-electrode assembly and a pair of separators arranged on both outer sides of the electrolyte membrane-electrode assembly.

The electrolyte membrane-electrode junction includes an electrolyte membrane 70, an anode catalyst layer 12 formed on one main surface of the electrolyte membrane 70, a cathode catalyst layer 13 formed on the other main surface of the electrolyte membrane 70, and an anode. The anode gas diffusion layer 14 and the cathode gas diffusion layer 15 are provided outside the catalyst layer 12 and the cathode catalyst layer 13.

The anode catalyst layer 12 and the anode gas diffusion layer 14 form an anode, and the cathode catalyst layer 13 and the cathode gas diffusion layer 15 form a cathode.

The pair of separators arranged on both outer sides of the electrolyte membrane-electrode assembly are the anode separator 16 arranged on the outside of the anode gas diffusion layer 14 and the cathode separator 17 arranged on the outside of the cathode gas diffusion layer 15. ..

Next, a method for producing the electrolyte membrane 70 having the alignment layer 71a, which is a point of the invention of the electrolyte membrane 70 and the fuel cell according to the present embodiment, will be described with reference to FIG. In FIG. 8, the same components as those in FIGS. 2 and 7 are given the same reference numerals.

As shown in FIG. 8, the electrolyte membrane 70 having the alignment layer 71a is produced by the following procedure. First, an electrolyte membrane 23 having no alignment layer is prepared and fixed to an adsorption plate 20 provided with an adsorption mechanism (FIG. 8A).

Next, in a state where the roller 22 to which the cloth 21 is attached is pushed into the electrolyte membrane 23 by a predetermined pushing amount, it is rotated at a predetermined rotation speed, and at the same time, the adsorption plate 20 to which the electrolyte membrane 23 is fixed is predetermined in a fixed direction. The surface of the electrolyte membrane 23 is rubbed by moving at the speed of (FIG. 8 (b)).

By this operation, a first electrolyte membrane 71 having an alignment layer 71a in which the main chain of the polymer constituting the electrolyte membrane is oriented in one direction (direction parallel to the main plane) is produced on one main surface (). FIG. 8 (c).

Here, the pushing amount is the position where the bristles of the cloth 21 attached to the roller 22 first come into contact with the surface of the electrolyte membrane 23 when the position of the roller 22 is changed with respect to the surface of the electrolyte membrane 23. Is the origin, and the amount of fluctuation in which the roller 22 is pushed toward the electrolyte membrane 23 from the origin.

Next, a second electrolyte membrane 72 having no alignment layer is prepared, and the first electrolyte membrane 71 and the second electrolyte membrane 71 are in contact with the main surface on which the alignment layer 71a of the first electrolyte membrane 71 is formed. The electrolyte membranes 72 are overlapped (FIG. 8 (d)). Subsequently, the first electrolyte membrane 71 and the second electrolyte membrane 72 are joined by hot pressing (FIG. 8 (e)).

By the above series of operations, an alignment layer 71a in which the main chains of the polymers constituting the electrolyte membrane 70 are oriented in one direction (parallel to the main surface) is formed inside the electrolyte membrane 70 (intermediate layer). Therefore, an electrolyte membrane 70 having an alignment layer 71a in which one alignment axis substantially parallel to the main surface is formed is obtained.

As described above, in the present embodiment, the electrolyte membrane 70 contains the alignment layer 71a in which the main chain of the polymer constituting the electrolyte membrane 70 is oriented in one direction (direction parallel to the main surface) inside (intermediate). By having the layer), in the alignment layer 71a, the interaction between the molecular chains of the polymer is increased, the free volume is reduced, and the permeation amount of the reaction gas through the electrolyte membrane 70 can be significantly reduced. ..

Further, in the present embodiment, a fuel cell in which the permeation amount of the reaction gas is reduced is provided by using the electrolyte membrane 70 having an orientation layer 71a inside (intermediate layer) and having excellent blocking property of the reaction gas. can do.

In such a fuel cell, the permeation amount of the reaction gas through the electrolyte membrane 70 is reduced, and the reaction of the reaction gas inside the electrolyte membrane 70 is suppressed to suppress the deterioration of the electrolyte membrane 70 over time. Therefore, it is possible to suppress a decrease in the battery voltage of the fuel cell.

Hereinafter, the electrolyte membrane and the fuel cell according to the present embodiment will be described in more detail based on specific examples, but the present invention is not necessarily limited to the contents of the specific raw materials and the like used below. is not.

(Example 4)
(1) Preparation of Electrolyte Membrane Nafion 112 (manufactured by DuPont Co., Ltd.) was prepared as an electrolyte membrane having no alignment layer, and was adsorbed and fixed on an adsorption plate.

Subsequently, a roller having a cloth (manufactured by Naganuma Gauge Mfg. Co., Ltd., product type: CFT055) attached to the surface is pushed into one main surface of the Nafion 112 with a pushing amount of 1 mm, and is rotated at a rotation speed of 10 s ^-1 . Then, the suction plate is moved in one direction at a speed of 5 mm / s, and one main surface of the Nafion 112 is rubbed in one direction to form an alignment layer having one alignment axis on one main surface of the Nafion 112. did.

Next, another Nafion 112 (manufactured by DuPont Co., Ltd.) having no alignment layer was prepared, and the Nafion 112 on which the alignment layer was formed by the above procedure was superposed so that the alignment layer was in contact with the Nafion 112, and then hot. Both Nafions 112 were bonded by thermocompression bonding at 100 ° C. and 1 MPa for 2 minutes by pressing to prepare an electrolyte membrane having an orientation layer inside (hereinafter referred to as electrolyte membrane E).

When the birefringence Δn, the surface orientation coefficient ΔP, and the hydrogen permeation amount Vh of the electrolyte membrane E thus produced were evaluated by the above-mentioned evaluation methods, the birefringence Δn, the surface orientation coefficient ΔP, and the hydrogen permeation amount Vh of the electrolyte membrane E were (1). As shown in Table 2), the electrolyte membrane E shows large values of birefringence Δn and plane orientation coefficient ΔP, and the main chain of the polymer is regularly oriented in a certain direction, and the electrolyte. Membrane E showed a good hydrogen blocking property with a small amount of hydrogen permeation.

(2) Preparation of Unit Battery Using the electrolyte membrane E, a unit battery (hereinafter referred to as unit battery E) was prepared by the same procedure as that described in Example 1 (2) described above.

When the battery performance of the unit battery E thus produced was evaluated by the same evaluation method as the above-mentioned evaluation method, the battery voltage of the unit battery E is as shown in (Table 2), and the unit battery E has a high battery voltage at the initial stage. The battery voltage did not decrease even after 2000 hours, and the durability was excellent.

(Comparative Example 2)
Two Nafion 112 (manufactured by DuPont Co., Ltd.) were prepared and laminated as an electrolyte membrane having no alignment layer, and then heat-pressed with a hot press at 100 ° C. and 1 MPa for 2 minutes. An electrolyte membrane (hereinafter referred to as electrolyte membrane F) obtained by joining a sheet of Nafion 112 is prepared, and the double refraction Δn, the plane orientation coefficient ΔP, and the hydrogen permeation amount Vh of the electrolyte membrane F are determined by the same evaluation method as the above-mentioned evaluation method. evaluated.

The double refraction Δn, surface orientation coefficient ΔP, and hydrogen permeation amount Vh of the electrolyte membrane F are as shown in Table 2 below, and the electrolyte membrane F shows small values for the double refraction Δn and the surface orientation coefficient ΔP, and is the main polymer. The chains were randomly arranged, and the electrolyte membrane F had a larger amount of hydrogen permeation and was inferior in hydrogen blocking property as compared with the electrolyte membrane (electrolyte membrane E) of Example 4.

Next, using the electrolyte membrane F, a unit battery (hereinafter referred to as unit battery F) is produced by the same procedure as that described in Example 1 (2) described above, and the same evaluation method as the evaluation method described above is performed. The battery performance of the unit battery F was evaluated.

The battery voltage of the unit battery F is as shown in (Table 2), and the initial battery voltage of the unit battery F was the same as that of the unit battery (unit battery E) of the fourth embodiment, but after 2000 hours had passed. The battery voltage was significantly reduced, and the durability was inferior to that of the unit battery (unit battery E) of Example 4.

The above results are summarized in (Table 2).

電解質膜の水素透過性に関し、本実施例に係る電解質膜（電解質膜Ｅ）は、水素の透過量が少ないものであった。これは、電解質膜が配向層を有することで、配向層において、電解質膜を構成する高分子の主鎖が一定の方向に配向することにより、高分子の分子鎖間の相互作用が大きくなって自由体積が減少し、水素に対する遮断性が向上したためと考えられる。

Regarding the hydrogen permeability of the electrolyte membrane, the electrolyte membrane (electrolyte membrane E) according to this example had a small amount of hydrogen permeation. This is because the electrolyte membrane has an alignment layer, and the main chains of the polymer constituting the electrolyte membrane are oriented in a certain direction in the alignment layer, so that the interaction between the molecular chains of the polymer becomes large. It is considered that this is because the free volume is reduced and the blocking property against hydrogen is improved.

On the other hand, the electrolyte membrane (electrolyte membrane F) according to the comparative example had a larger amount of hydrogen permeation than the electrolyte membrane (electrolyte membrane E) according to the present embodiment. It is considered that this is because the electrolyte membrane does not have an alignment layer, so that the main chains of the polymers constituting the electrolyte membrane are randomly arranged, the free volume of the polymer is increased, and the blocking property against hydrogen is lowered. Be done.

Further, regarding the battery performance of the unit battery, the battery voltage of the unit battery (unit battery E) according to the present embodiment did not decrease even after 2000 hours had passed. This is because the electrolyte membrane has an orientation layer, which reduces the permeation amount of the reaction gas, so that the reaction of the reaction gas inside the electrolyte membrane is suppressed, and the deterioration of the electrolyte membrane over time can be prevented. It is thought that it was a cause.

On the other hand, the unit battery (unit battery F) according to the comparative example has a significantly reduced battery voltage after 2000 hours, and is inferior in durability to the unit battery (unit battery E) according to the present embodiment. It was. It is considered that this is because the electrolyte membrane does not have an alignment layer, so that the permeation amount of the reaction gas increases, the reaction gas reacts inside the electrolyte membrane, and the electrolyte membrane deteriorates over time.

From the above hydrogen permeation evaluation test of the electrolyte membrane, it was confirmed that the permeation amount of the reaction gas of the electrolyte membrane E produced in the present embodiment is reduced. Further, from the battery performance evaluation test of the unit battery, it was confirmed that the unit battery E produced in the present embodiment does not decrease in the battery voltage and exhibits excellent durability.

(Modification example)
Although one embodiment of the present invention has been described above, the present invention is not limited to such an embodiment, and various configurations can be adopted without departing from the spirit of the present invention.

(Modification example 1)
In each of the above-described embodiments, Nafion 112 is used as the electrolyte membrane, but the electrolyte membrane is a hydrogen ion having a fluorine-containing polymer as a skeleton and having functional groups such as a sulfonic acid group, a carboxyl group, and a phosphoric acid group. A conductive electrolyte membrane can be used, and for example, other electrolyte membranes such as Aciplex (registered trademark) and Flemion (registered trademark) can be used.

(Modification 2)
In each of the above-described embodiments, the electrolyte membrane is an electrolyte membrane having one or two orientation layers, but the electrolyte membrane is an electrolyte membrane having two or more orientation layers. It doesn't matter.

(Modification 3)
The amount of pushing of the roller, the number of rotations of the roller, and the moving speed of the adsorption plate on which the electrolyte membrane is fixed when producing the electrolyte membrane having the alignment layer are not limited to the conditions described in each of the above-described embodiments, and are appropriately changed. It doesn't matter.

(Modification example 4 )
In the above-described first embodiment, the anode is arranged so as to be in contact with the alignment layer of the electrolyte membrane to prepare the unit battery, but the cathode is arranged so as to be in contact with the alignment layer of the electrolyte membrane to prepare the unit battery. It doesn't matter.

As described above, according to the electrolyte membrane according to the present invention, the permeation amount of the reaction gas through the electrolyte membrane can be reduced, and when used by incorporating it into a fuel cell, a high battery voltage is maintained for a long period of time. Therefore, it can be applied to applications of fuel cells used in household cogeneration systems, electric vehicle power supplies, portable power supplies, and the like.

10, 30, 50, 70 Electrolyte film 10a, 30a, 50a, 71a Aligned layer 10b, 30b, 50b, 71b Non-oriented layer 11, 31, 51, 73 Unit battery 12 Anode catalyst layer 13 Cathode catalyst layer 14 Anode gas diffusion layer 15 Cathode gas diffusion layer 16 Anode separator 17 Cathode separator 20 Adsorption plate 21 Cloth 22 Roller

Claims (2)

An electrolyte membrane obtained by rubbing a membrane made of a polymer having hydrogen ion conductivity and a salt substitution rate of less than 1%.
An electrolyte membrane having alignment layers in which the main chains of the polymer are oriented in a plurality of directions substantially parallel to the main surfaces of the electrolyte membrane only on the surfaces of both main surfaces of the electrolyte membrane. The electrolyte membrane according to claim 1 and
Anodes and cathodes arranged on both main surfaces with the electrolyte membrane in between,
Fuel cell with.

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