JP2006344517A - Manufacturing method of fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent wrinkles of an electrolyte membrane, wrinkles and cracks of an electrode by suppressing swelling of the electrolyte membrane when an electrode is formed by directly applying a slurry to the surface of the electrolyte membrane and drying it to form a fuel cell. The purpose is to provide.
A manufacturing method of a fuel cell including a coating step of applying a slurry containing at least a polymer material and a solvent to an electrolyte membrane, wherein an atmospheric temperature of the coating step is a solvent component contained in the solvent. Of these, a method for producing a fuel cell, characterized in that at least the saturated vapor pressure of the solvent component having the highest volatility is 80 kPa or more.
[Selection figure] None

Description

  The present invention relates to a method for manufacturing a fuel cell.

  A fuel cell directly converts chemical energy into electrical energy by supplying fuel and an oxidant to two electrically connected electrodes and causing the fuel to be oxidized electrochemically. Unlike thermal power generation, it is not subject to the Carnot cycle, and exhibits high energy conversion efficiency. A fuel cell is usually configured by laminating a plurality of single cells having a basic structure in which an electrolyte membrane is sandwiched between a fuel electrode and an oxidant electrode, and among them, a solid polymer using a solid polymer electrolyte membrane as an electrolyte membrane Electrolytic fuel cells are particularly attracting attention as portable and mobile power sources because of their advantages such as easy miniaturization and operation at low temperatures.

The electrode provided in the polymer electrolyte fuel cell usually has a multilayer structure in which a catalyst layer and a gas diffusion layer are laminated in order from the polymer electrolyte membrane side. For example, the following methods (1) to (3) are known as methods for forming electrodes having such a structure on both surfaces of a solid polymer electrolyte membrane. That is,
(1) First, a catalyst layer slurry is applied onto a substrate such as polytetrafluoroethylene and dried to form a catalyst layer, and then the substrate on which the surface on which the catalyst layer is formed is on the electrolyte membrane side And the electrolyte membrane are pressure-bonded, the substrate is peeled off to obtain an electrolyte membrane having a catalyst layer, and then a gas diffusion layer is formed on the catalyst layer,
(2) A method of pressure-bonding the gas diffusion layer, on which the catalyst layer is formed by applying and drying the slurry for the catalyst layer on the surface, with the electrolyte membrane such that the catalyst layer is on the electrolyte membrane side,
(3) A method in which a catalyst layer slurry is directly applied on an electrolyte membrane and dried to form a catalyst layer, and then a gas diffusion layer is formed on the catalyst layer.
The method (3) is more advantageous than the methods (1) and (2) because the crimping step can be omitted at least once.

When a fuel cell using an electrolyte membrane having a large area, such as a fuel cell for automobiles, is produced by the method (3) above, the coating process of the slurry for the catalyst layer on the surface of the electrolyte membrane is performed at room temperature and normal pressure. Has been done under conditions. At this time, the solvent contained in the catalyst layer slurry diffuses into the electrolyte membrane, and the electrolyte membrane is in a swollen state. The solvent in the catalyst layer slurry applied onto the electrolyte membrane evaporates by the drying step subsequent to the coating step, and a catalyst layer is formed. At this time, the solvent of the catalyst layer slurry soaked in the electrolyte membrane is removed. By evaporating, the electrolyte membrane dries and shrinks. As a result, wrinkles are generated in the electrolyte membrane, and accordingly, wrinkles and cracks are also generated in the catalyst layer formed on the electrolyte membrane.
Thus, when wrinkles or the like are generated in the electrolyte membrane or the catalyst layer, the adhesion with other layers such as a gas diffusion layer subsequently formed on the catalyst layer is poor, which may cause a decrease in the performance of the fuel cell. In addition, the configuration of the electrode pattern may be limited. Furthermore, the cracking of the catalyst layer may deteriorate the performance of the fuel cell due to physical damage such as the cracks biting into the electrolyte membrane when pressure is applied to the catalyst layer.

Therefore, various efforts have been made to suppress the occurrence of wrinkles and the like in the electrolyte membrane and the electrode. For example, by reducing the degree of swelling / shrinkage of the electrolyte membrane itself by providing a reinforcing layer between the electrolyte membrane and the electrode, or increasing the concentration of ethanol used as the solvent component of the catalyst layer slurry, A device has been devised such as suppressing the swelling of the electrolyte membrane by improving the volatility of the solvent in the slurry.
However, when a reinforcing layer is provided between the electrolyte membrane and the electrode, there is a problem that the power generation performance of the fuel cell is lowered. Further, when the ethanol concentration in the catalyst layer slurry is increased, there may be a case where the catalyst layer slurry cannot be prepared due to ignition.

  In order to reduce the manufacturing process of the fuel cell and to form a uniform electrode layer, a polymer material in a state where the solid polymer film is held by vacuuming on a porous plate held at a constant temperature. A method has been proposed in which an electrode layer is formed by applying a slurry containing a catalyst to a solid polymer film (Patent Document 1). Patent Document 1 describes an example in which ethanol is used as a solvent for the slurry and the temperature of the porous plate is maintained at a constant temperature of 60 ° C.

JP 2003-100314 A

However, under the conditions described in the example of Patent Document 1 where the porous plate holding temperature is 60 ° C. (saturated vapor pressure of ethanol: about 350 mmHg = about 47 kPa), the evaporation of ethanol is accelerated and the drying of the slurry is accelerated. Even if it can, ethanol will permeate into the electrolyte membrane before it evaporates, and thus the swelling of the electrolyte membrane cannot be sufficiently suppressed. As a result, wrinkles and cracks in the electrolyte membrane and electrodes are generated.
The present invention has been accomplished in consideration of the above-mentioned problems. When an electrode is formed by directly applying a slurry to the surface of the electrolyte membrane and drying it, the electrolyte membrane is reduced by suppressing swelling of the electrolyte membrane. An object of the present invention is to provide a method of manufacturing a fuel cell that prevents wrinkling and cracking of an electrode.

  A fuel cell manufacturing method provided by the present invention is a fuel cell manufacturing method including a coating step in which a slurry containing at least a polymer material and a solvent is applied to an electrolyte membrane, wherein the ambient temperature in the coating step is Among the solvent components contained in the solvent, the solvent component having at least the highest volatility is a temperature at which the saturated vapor pressure is 80 kPa or more.

  According to the method for manufacturing a fuel cell of the present invention, the atmospheric temperature in the step of applying the slurry to the electrolyte membrane is set so that the saturated vapor pressure in the pure substance having the highest volatility among the solvent components contained in the slurry is 80 kPa. By setting the temperature to the above, that is, the temperature at which the solvent component easily evaporates, the evaporation of the solvent component can be promoted, and the diffusion of the solvent component into the electrolyte membrane can be suppressed. As a result, it is possible to suppress swelling of the electrolyte membrane.

  In order to further suppress the diffusion of the solvent component into the electrolyte membrane, the atmospheric temperature in the coating step is set such that the ratio of one or more solvent components having a saturated vapor pressure of 80 kPa or more is the total solvent in the slurry. The temperature is preferably 50% by volume or more based on the amount. Moreover, the diffusion of the solvent component into the electrolyte membrane can also be suppressed by setting the atmospheric temperature in the coating step to a temperature at which the saturated vapor pressure is 90 kPa or higher.

In the case where a solid polymer electrolyte membrane having a particularly high swellability is used as the electrolyte membrane, the fuel cell production method of the present invention is suitable.
The method for applying the slurry to the electrolyte membrane is not particularly limited, but the spray method is particularly preferable because the solvent component has high evaporability.

  According to the fuel cell manufacturing method of the present invention, when the slurry for forming the catalyst layer or other layers is applied on the electrolyte membrane, the electrolyte membrane is prevented from swelling, and the wrinkles of the electrolyte membrane Since it is possible to suppress the occurrence of wrinkles and cracks in layers such as the catalyst layer formed on the electrolyte membrane, it is formed on the electrolyte membrane and the interlayer formed on the surface thereof, and further on the electrolyte membrane and the surface thereof. The layer laminated on the layer is excellent in adhesion. Therefore, a decrease in battery performance due to poor adhesion of each layer is prevented. Further, since the smoothness of the electrolyte membrane and the layer formed on the surface thereof is maintained, the configuration of the electrode pattern is not limited, and the degree of freedom in electrode design is high.

In addition, since the diffusion of the solvent component itself into the electrolyte membrane in the slurry application step is suppressed, the swelling can be suppressed even when an electrolyte membrane that easily swells is used. Therefore, the manufacturing method of the present invention is rich in the selectivity of the electrolyte membrane material.
In addition, the method of the present invention does not require labor and cost such as providing a new functional layer to prevent swelling of the electrolyte membrane, preparing a solvent having excellent volatility, and using a vacuum drawing device. It is a simple method.

  The method for producing a fuel cell according to the present invention is a method for producing a fuel cell comprising a coating step in which a slurry containing at least a polymer material and a solvent is applied to an electrolyte membrane, wherein the ambient temperature in the coating step is the solvent. Is a temperature at which the saturated vapor pressure of the solvent component having the highest volatility is 80 kPa or more.

  The present invention applies the slurry at a temperature at which the saturated vapor pressure of at least the most volatile solvent component pure substance among the solvent components contained in the slurry is 80 kPa or more, that is, at an atmospheric temperature at which the solvent components are likely to evaporate. It has a special feature. By promoting the evaporation of the solvent component and suppressing the diffusion of the solvent component into the electrolyte membrane, the swelling of the electrolyte membrane is suppressed, so that the generation of wrinkles due to the swelling / shrinkage of the membrane can be prevented. Furthermore, by preventing swelling and shrinkage of the electrolyte membrane and generation of wrinkles, it is possible to prevent generation of wrinkles and cracks in a layer (slurry layer) formed by applying slurry on the membrane.

  In this way, by forming a slurry layer having a smooth surface on the surface thereof while suppressing wrinkles on the electrolyte membrane, the electrolyte membrane and the slurry layer formed on the surface, and further, the electrolyte membrane and The adhesion between the layers laminated on the slurry layer formed on the surface is improved, and the battery performance is improved. Furthermore, since the electrode pattern of the layer formed on the slurry layer or the surface of the electrolyte membrane opposite to the surface on which the slurry layer is formed is not limited, the degree of freedom in designing the fuel cell is increased. Moreover, since physical damage to the electrolyte membrane due to cracks generated in the slurry layer can be suppressed, it is possible to further prevent the battery performance from being lowered. In addition, since a smooth slurry layer can be formed even for highly swellable electrolyte membranes, there is an advantage that the selectivity of the electrolyte membrane to be used is widened.

  In addition, the method of the present invention suppresses the swelling of the electrolyte membrane by optimally setting the atmospheric temperature in the coating process, and a new functional layer is provided to prevent the electrolyte membrane from swelling, This eliminates the need for labor and costs such as the preparation of an excellent solvent and the use of a vacuuming device. Moreover, since the temperature of the coating atmosphere as described above is set using the saturated vapor pressure in the pure substance of the solvent component to be used as an index, the ambient temperature is grasped by trial and error according to the solvent component to be used. A suitable temperature can be easily obtained without requiring a process.

  In the present invention, the atmospheric temperature in the coating process (hereinafter sometimes referred to as the atmospheric temperature T) refers to the temperature of the electrolyte membrane itself or the temperature around the electrolyte membrane. For example, when controlling the temperature of the electrolyte membrane directly using a heating device or the like, it refers to the temperature of the electrolyte membrane itself or the temperature of the heating part of the heating device, and the temperature around the electrolyte membrane is heated. Is controlled by a heating device that heats the periphery of the electrolyte membrane, for example, the temperature inside the heater cabinet.

  In the present invention, the atmospheric temperature T in the coating process is set to a temperature at which the saturated vapor pressure of the solvent component having the highest volatility among the solvent components contained in the solvent in the slurry is 80 kPa or more. Here, the saturated vapor pressure of the solvent component (hereinafter sometimes simply referred to as a saturated vapor pressure) is a saturated vapor pressure that the target solvent component shows in a pure substance, that is, a one-component system. The specific saturated vapor pressure of each solvent component can be obtained from various documents in addition to actual measurement, and a vapor pressure curve indicating the relationship between temperature and saturated vapor pressure is given for many substances. Examples of readily available literature include a chronology of science (written by NAOJ, publisher: Maruzen).

Among the solvent components, at a temperature at which the saturated vapor pressure of the solvent component having the highest volatility is less than 80 kPa, the evaporation of the solvent cannot be accelerated sufficiently, and the solvent diffuses widely into the electrolyte membrane. Swell. In order to more reliably suppress the swelling of the electrolyte membrane, it is preferable to set the ambient temperature T so that the saturated vapor pressure is 90 kPa or more.
On the other hand, if the coating process atmosphere temperature T is such that the saturated vapor pressure becomes excessive, the solvent component in the slurry evaporates too quickly, so that the resulting slurry layer may be cracked. From such a viewpoint, it is preferable that the coating process atmosphere temperature T is set to a temperature at which the saturated vapor pressure is 200 kPa or less, particularly 150 kPa or less.

  Further, the solvent in the slurry may be composed of one type of solvent component, or may be a combination of two or more types of solvent components. In the present invention, the atmospheric temperature T is set to a temperature at which the saturated vapor pressure of the solvent component having the highest volatility among the solvent components contained in the solvent is 80 kPa or more. When composed of components, the temperature at which the saturated vapor pressure of the solvent component is 80 kPa or more, and when composed of two or more types of solvent components, the temperature at which the saturated vapor pressure of at least the most volatile solvent component is at least 80 kPa However, the temperature is particularly preferably 90 kPa or more.

  From the viewpoint of promoting evaporation of the solvent component in order to prevent the electrolyte membrane from swelling, the ambient temperature T is a temperature at which more solvent component is easily evaporated, that is, the saturated vapor pressure of more solvent component is 80 kPa or more. It is preferable to set the temperature. Specifically, it is preferable that the ratio of the one or two or more solvent components having a saturated vapor pressure of 80 kPa or more is a temperature at which 50% by volume or more with respect to the total amount of the solvent in the slurry. It is preferable to set the temperature so that the saturated vapor pressure of all the solvent components contained in is 80 kPa or more.

The atmospheric temperature T of the coating process in which the saturated vapor pressure of the solvent component is 80 kPa or more is a temperature ( _Tboil −15 ° C.) that is 15 ° C. lower than the boiling point T _boil (° C.) of the solvent component, and the coating process atmospheric temperature T Can be easily set with reference to a temperature such that T> T _boil −15 ° C. For example, among the solvent components contained in the solvent, the temperature at which the saturated vapor pressure of the plurality of solvent components is 80 kPa or more is a temperature that is 15 ° C. lower than the boiling point of the solvent component having the highest boiling point among the plurality of solvent components. The atmospheric temperature T may be set to.

  The atmospheric temperature T in the coating process takes into consideration the conditions that affect the volatility such as the solvent components used (physical properties such as boiling point and ignitability), the combination of the solvent components, the concentration of the solvent components, and the heat resistance of the electrolyte membrane. It is preferable to set appropriately considering the balance of the entire process.

In the present invention, the slurry includes at least a polymer material and a solvent, and is not particularly limited as long as it is a slurry for forming a layer by directly applying to an electrolyte membrane and drying. And slurry for forming a layer additionally provided for the purpose of improving the performance of the fuel cell. The polymer material and the solvent contained in the slurry are not particularly limited as long as a layer can be formed on the electrolyte membrane surface using the slurry containing them.
The electrolyte membrane is not particularly limited as long as it shows swelling when contacted with a solvent, and may be organic or inorganic, such as a proton conductive solid polymer electrolyte membrane or an oxide. Examples thereof include solid polymer electrolyte membranes such as ion conductive solid polymer electrolyte membranes such as ions and hydroxide ions. Among these, the production method of the present invention is suitable when using a proton conductive solid polymer electrolyte membrane having a particularly high swellability typified by a perfluorosulfonic acid polymer membrane.

  Further, when the electrolyte membrane is a proton conductive solid polymer electrolyte membrane and the slurry is a slurry for a catalyst layer containing a polymer material, a catalyst material and a solvent, the effect obtained by the present invention is particularly high. . This is because the adhesion between the solid polymer electrolyte membrane and the catalyst layer has a great influence on the cell performance of the fuel cell, and the proton conductive solid polymer electrolyte membrane has a property of easily swelling.

  Hereinafter, the production method of the fuel cell of the present invention will be described in detail by taking as an example the case where the electrolyte membrane is a proton conductive solid polymer electrolyte membrane and the slurry is a slurry for a catalyst layer containing a polymer material, a catalyst material and a solvent. .

  Here, a configuration example of a polymer electrolyte fuel cell will be described with reference to FIG. In FIG. 1, a fuel electrode catalyst layer 2 is provided on one side of a proton conductive solid polymer electrolyte membrane 1, and an oxidant electrode catalyst layer 3 is provided on the other side. Further, gas diffusion layers 4 and 5 having electric conductivity and gas diffusibility are usually formed on the outer surfaces of the catalyst layers 2 and 3, and the fuel electrode 6 is composed of the fuel electrode catalyst layer 2 and the gas diffusion layer 4. The oxidant electrode 7 includes the oxidant electrode catalyst layer 3 and the gas diffusion layer 5. Usually, a reactive gas (fuel gas or oxidant gas) is supplied to each electrode of a membrane-electrode assembly composed of the fuel electrode 6, the electrolyte membrane 1, and the oxidant electrode 7. In order to discharge excess gas, separators 10 and 11 that define gas flow paths 8 and 9 are provided outside the electrodes.

  First, a proton conductive solid polymer electrolyte membrane (hereinafter, simply referred to as an electrolyte membrane in the present embodiment) is prepared. The proton conductive solid polymer electrolyte membrane is not particularly limited as long as it is a solid polymer electrolyte membrane capable of conducting protons, but it is represented by Nafion (trade name, manufactured by DuPont). Such fluorine-containing polymers or non-fluorinated hydrocarbon polymers having at least a proton exchange group such as a sulfonic acid group, a carboxylic acid group, a phosphonic acid group, and a phosphoric acid group can be exemplified. As the electrolyte membrane, a commercially available product can be used.

Next, a slurry for a catalyst layer containing a polymer material, a catalyst material, and a solvent is prepared.
As the polymer material contained in the catalyst layer slurry, a polymer material having proton conductivity is usually used. The proton-conducting polymer may be a polymer material capable of conducting protons, and is not limited to organic materials and inorganic materials. However, fluorine-containing polymers represented by perfluorosulfonic acid polymers are not particularly limited. Examples thereof include those having a proton exchange group such as at least a sulfonic acid group, a carboxylic acid group, a phosphonic acid group, and a phosphoric acid group with a polymer or a non-fluorinated hydrocarbon polymer as a skeleton. These proton conductive polymers may be the same as the material constituting the electrolyte membrane or may be different. The polymer material contained in the slurry for the catalyst layer is not limited to the proton conductive polymer, and other polymer materials such as a water-repellent polymer and a binder can be used. You may combine.

  As the catalyst material, catalyst particles in which a catalyst component is supported on a conductive material such as a carbon material such as carbonaceous particles and carbonaceous fibers are preferably used. The catalyst component is not particularly limited as long as it has a catalytic action on the hydrogen oxidation reaction at the fuel electrode and the oxygen reduction reaction at the oxidant electrode. For example, platinum, ruthenium, iron, nickel, manganese An alloy of a metal such as platinum and the like can be used.

The slurry for the catalyst layer can be obtained by mixing and dispersing the above polymer material, catalyst material, and other components as required in a solvent.
The solvent is not particularly limited, and examples thereof include a mixed solvent of ethanol and water, a mixed solvent of methanol and water, a mixed solvent of propanol and water, and a mixed solvent of ethanol, butanol and water. The concentration of each solvent component is appropriately selected in consideration of the dispersibility of the polymer material, the applicability of the resulting slurry for the catalyst layer, ignition, drying, viscoelasticity, dripping, and the like. For example, when a mixed solvent of ethanol and water is used as the solvent, ethanol: water = 0.5: 1-3: is usually considered in consideration of both the volatility of the resulting mixed solvent and the ignition of ethanol. It is preferable to use a mixture with a volume ratio of 1.
The concentration of each component in the slurry for the catalyst layer is not particularly limited, and as a polymer material, the proton conductive polymer is 0.05 to 5% by weight, and the catalyst component is about 0.01 to 10% by weight. do it.

Subsequently, the obtained catalyst layer slurry is applied to the electrolyte membrane surface. In the production method of the present invention, the atmospheric temperature T in this coating step is set to a temperature at which the saturated vapor pressure of the solvent component having the highest volatility among the solvent components contained in the catalyst layer slurry is 80 kPa or more. To do. The method of controlling (adjusting) the atmospheric temperature T is not particularly limited. For example, the electrolyte membrane is placed on a heating plate and the electrolyte membrane is directly heated, or the electrolyte membrane is placed in a heated heater cabinet. For example, a method of applying the catalyst layer slurry to the electrolyte membrane in a state where the electrolyte membrane is installed and the periphery of the electrolyte membrane is heated.
Examples of the method for applying the slurry for the catalyst layer to the electrolyte membrane include a spray method, a screen printing method, a brush coating method, and a die coating method, and are not particularly limited, but the spray method is particularly preferable. In the spray method, the slurry can be uniformly applied to the surface of the electrolyte membrane, and since evaporation of the solvent is promoted during spraying, the swelling of the electrolyte membrane can be further suppressed.

Hereinafter, a method for forming the catalyst layer using the spray method will be described.
As a spray device for directly spraying the catalyst layer slurry onto the electrolyte membrane, for example, a spray gun 16 having a nozzle at the tip, and a slurry pot (not shown) containing the catalyst layer slurry 15 connected to the spray gun 16 are illustrated. And a compressor (not shown) electrically connected to the spray gun 16 (see FIG. 2).

The electrolyte membrane 13 is disposed on the plate 12, and the catalyst layer slurry 15 is sprayed onto the surface of the electrolyte membrane 13 by a spray device as described above through a mask 14 for forming a catalyst layer having a desired shape.
The conditions for spraying the catalyst layer slurry onto the electrolyte membrane are preferably an atomizing air pressure of 0.1 to 1.0 MPa, a spraying height of 10 to 200 mm, and a droplet diameter of 0.001 to 0.1 mm. Here, “spraying height” means the distance from the electrolyte membrane to the nozzle tip of the spray nozzle head. When the air pressure is less than 0.1 MPa, since the air pressure is small, the droplets become large and the slurry cannot be applied neatly to the electrolyte membrane. On the other hand, when the air pressure exceeds 1.0 MPa, since the air pressure is large, the droplets are small, the slurry is scattered, and the yield is lowered.

Further, when the spray height is less than 10 mm, the electrolyte membrane and the nozzle tip are too close to be sprayed, and when it exceeds 200 mm, the slurry is scattered around and the yield is lowered. . On the other hand, when the droplet diameter is less than 0.001 mm, the slurry scatters around and the yield decreases. On the other hand, when the droplet diameter exceeds 0.1 mm, the drying of the solvent in the slurry on the electrolyte membrane is slow, which may reduce the swelling suppression effect of the electrolyte membrane.
A catalyst layer is formed by providing a drying step and drying the slurry for the catalyst layer applied under the above temperature conditions. At this time, it is preferable to form the catalyst layer so that the amount of the catalyst component per unit area of the catalyst layer is about 0.01 to 5 mg / cm ² .

As described above, an electrolyte membrane having a catalyst layer formed on one surface usually has a catalyst layer also formed on the other surface.
A gas diffusion layer is usually formed on the catalyst layer formed on the electrolyte membrane surface. Examples of the gas diffusion layer include those made water-repellent by coating the surface of a conductive porous material such as carbon paper, carbon cloth, carbon felt with polytetrafluoroethylene. It can be used for both the diffusion layer and the oxidant electrode gas diffusion layer. A membrane-electrode assembly is obtained by sandwiching and joining the electrolyte membrane having the catalyst layer formed between two gas diffusion layers.
The obtained membrane-electrode assembly is made into a fuel cell by sandwiching it with a separator by a general method, and a fuel cell is obtained by laminating a plurality of fuel cells.

  Here, the case where the electrolyte membrane is a proton conductive solid polymer electrolyte membrane and the slurry is a slurry for a catalyst layer has been described as an example, but examples of the electrolyte membrane include oxide ions and hydroxide ions. An ion conductive solid polymer electrolyte membrane other than protons can also be used.

<Production of electrolyte membrane with catalyst layer>
(Example)
First, 5 g of carbon particles carrying 40% by weight of platinum, 3 g of perfluorosulfonic acid resin (trade name Nafion, manufactured by DuPont), and 150 ml of a solvent (mixture of ethanol: water = 1: 1 by volume) Was kneaded to prepare a slurry for the catalyst layer. Next, the obtained catalyst layer slurry was applied to the surface of a perfluorosulfonic acid film (thickness 50 μm, trade name Nafion, manufactured by DuPont) placed on a plate with a temperature control function with a spray gun through a mask ( The platinum coating amount was 0.5 mg / cm ² ) to form a catalyst layer (see FIG. 2). At this time, the temperature of the plate was set to 80 ° C. (saturated vapor pressure of ethanol: about 800 mmHg = about 107 kPa). Subsequently, a catalyst layer was formed on a surface different from the surface on which the catalyst layer of the perfluorosulfonic acid film was formed by the same method (the plate temperature was the same) to obtain an electrolyte membrane with a catalyst layer.

(Comparative example)
An electrolyte membrane with a catalyst layer was produced by the same method except that the plate temperature was 30 ° C. (saturated vapor pressure of ethanol: about 80 mmHg = about 11 kPa) in the production of the membrane-electrode assembly of the above example.

<Evaluation by visual observation of electrolyte membrane with catalyst layer>
The electrolyte membrane of the example in which the plate temperature was set to 80 ° C. and the slurry for the catalyst layer was applied was significantly larger than the electrolyte membrane of the comparative example in which the plate temperature was set to 30 ° C. and the slurry for catalyst loading was applied. There was little wrinkle, and the catalyst layer formed on the surface had few wrinkles, and no cracks were observed.

It is sectional drawing which showed the example of 1 structure of the polymer electrolyte fuel cell. It is a figure explaining the method to apply | coat the slurry to an electrolyte membrane in the fuel cell manufacturing method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Proton conductive solid polymer electrolyte membrane 2 ... Fuel electrode catalyst layer 3 ... Oxidant electrode catalyst layer 4 ... Gas diffusion layer 5 ... Gas diffusion layer 6 ... Fuel electrode 7 ... Oxidant electrode 8 ... Gas flow path 9 ... Gas Flow path 10 ... Separator 11 ... Separator 12 ... Plate with temperature control function 13 ... Electrolyte membrane (perfluorosulfonic acid membrane)
14 ... Mask 15 ... Slurry for catalyst layer 16 ... Spray gun

Claims (5)

A method for producing a fuel cell comprising a coating step of applying a slurry containing at least a polymer material and a solvent to an electrolyte membrane,
The method for producing a fuel cell, wherein the atmospheric temperature in the coating step is a temperature at which a saturated vapor pressure of at least the highest volatile solvent component among the solvent components contained in the solvent is 80 kPa or more .   The atmosphere temperature in the coating step is a temperature at which the ratio of one or more solvent components having a saturated vapor pressure of 80 kPa or more is 50% by volume or more based on the total amount of solvent in the slurry. The manufacturing method of the fuel cell as described in 2.   The manufacturing method of the fuel cell according to claim 1 or 2, wherein the atmospheric temperature in the coating step is a temperature at which the saturated vapor pressure is 90 kPa or more.   The method for producing a fuel cell according to any one of claims 1 to 3, wherein the electrolyte membrane is a solid polymer electrolyte membrane. The method for manufacturing a fuel cell according to claim 1, wherein the method of applying the slurry to the electrolyte membrane is a spray method.

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