JP2000223131A - Fuel cell, separator used therefor and their manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily manufacture a separator allowing a rapid discharge of water generated in a channel for a fuel gas or an oxidizing gas to secure smooth supply of the fuel gas or the oxidizing gas to an electrode. SOLUTION: A manufacturing method of this separator includes a process S12 wherein a laminate is assembled by alternately laminating separator-forming members for forming separators and sheet materials a process S14 wherein a gas mistily containing a hydrophilic paint is streamed down through channels formed in the laminate; processes S16, S18 wherein the laminate is dried and disassembled, and a process wherein the separators are taken out. Thereby, a coating film made of a hydrophilic material is formed on a surface of a portion of the separator to be formed with the channel for a fuel gas or an oxidizing gas. The hydrophilic coating film is formed on only a required portion by only streaming the gas down through the laminated body, so as to easily form the separator allowing a rapid discharge of water generated in the channel for the fuel gas or the oxidizing gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell, a separator used therefor, and a method for producing the same.
More specifically, the present invention relates to a fuel cell formed by laminating a power generation layer and a separator, a method of manufacturing the same, a separator used in a fuel cell, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In a polymer electrolyte fuel cell, a fuel gas containing hydrogen and an oxidizing gas containing oxygen are supplied to two electrodes (a fuel electrode and an oxygen electrode) opposed to each other with an electrolyte membrane interposed therebetween. As a result, reactions represented by the following equations (1) and (2) are performed, and chemical energy is directly converted to electric energy.

Anode reaction (fuel electrode) H ₂ → 2H ++ 2e ⁻ (1) Cathode reaction (oxygen electrode) 2H ++ 2e ⁻ + (1/2) O ₂ → H ₂ O (2)

In order to carry out this reaction continuously and smoothly, it is necessary to smoothly diffuse hydrogen ions generated by the reaction of the above formula (1) into the electrolyte at the fuel electrode. Since hydrogen ions move in a hydrated state, water is usually supplied to the fuel electrode by humidifying the fuel gas. When such a fuel gas is supplied, when the fuel cell has not reached the steady operating temperature, for example, immediately after the fuel cell has started operating, the water vapor in the fuel gas is condensed, and the condensed water smoothly flows to the fuel electrode of the fuel gas. In some cases, the supply is interrupted. For this reason, it is desired that the condensed water be quickly discharged. On the other hand, at the oxygen electrode, water is generated by the reaction of the above formula (2), and this water hinders a smooth supply of the oxidizing gas to the oxygen electrode. Therefore, it is necessary to quickly discharge the generated water from the oxygen electrode. .

[0005] As a fuel cell meeting such demands,
Japanese Patent Application Laid-Open Nos. 59-180978 and 62-1 disclose a method in which a fluororesin film exhibiting water repellency is formed on a surface on which a flow path for a fuel gas or an oxidizing gas is formed.
No. 76064). In this fuel cell, since the surface on which the flow path is formed exhibits water repellency, drainage of water generated in the flow path from the flow path is enhanced.

[0006]

However, in a fuel cell having a channel formed with a water-repellent fluororesin on the surface on which the flow channel is formed, if the width and depth of the flow channel are reduced, the water generated in the flow channel causes However, there is a problem that the supply of the fuel gas or the oxidizing gas to the electrode is obstructed by blocking a part of the electrode.

[0007] In response to such a problem, the present applicant has proposed a fuel cell having a film formed of a material exhibiting hydrophilicity on a surface on which a flow path is formed (Japanese Patent Application Laid-Open No. 8-138692).
In this fuel cell, the water generated in the flow path forms a thin layer on the surface of the coating made of a hydrophilic material and flows along the surface of the coating. And smooth supply of oxidizing gas to the electrodes.

The separator of the present invention not only ensures the smooth supply of fuel gas and oxidizing gas to the electrode by quickly discharging the water generated in the flow path, but also removes the water in a portion of the flow path where water easily accumulates. The purpose is to discharge more quickly. One of the objects of the present invention is to provide a method for producing a separator that constitutes a fuel cell having a coating made of a material exhibiting hydrophilicity on a surface on which a flow path is formed,
Another object is to provide a method for producing the separator of the present invention. Another object of the fuel cell of the present invention is to provide a fuel cell of a type different from the above-mentioned proposed fuel cell having a hydrophilic portion exhibiting hydrophilicity on the surface on which the flow path is formed. Another object is to secure the moisture retention of the electrolyte membrane by securing the moisture retention.
One of the objects of the method for manufacturing a fuel cell of the present invention is to provide a method for manufacturing such a different type of fuel cell, and one of the objects is to provide a method for manufacturing the fuel cell of the present invention. I do.

[0009]

Means for Solving the Problems and Actions and Effects Thereof The fuel cell of the present invention, the method of manufacturing the same, and the method of manufacturing the separator employ the following means to at least partially achieve the above object.

The method of manufacturing a separator according to the present invention is characterized in that the separator is laminated with a power generation layer comprising an electrolyte membrane and two electrodes sandwiching the electrolyte membrane, forms a partition between the power generation layers, and, when laminated, forms the power generation layer. A method for manufacturing a separator for a fuel cell, which forms a flow path for supplying fuel to the electrodes of the fuel cell, comprising: a forming member forming step of forming a separator forming member having a flow path constituting portion forming the flow path; A laminate forming step of laminating the formed separator forming member together with a sheet material to form a laminate, and causing the paint containing a material exhibiting hydrophilicity to flow down the flow path of the formed laminate to form the flow path. A film forming step of forming a film of the hydrophilic material on the surface of the component.

According to the method of manufacturing a separator of the present invention, a paint containing a material having hydrophilicity is caused to flow down in a flow path formed in a laminate formed by laminating a separator forming member and a sheet material. A film made of a material exhibiting hydrophilicity can be easily formed on the surface of the flow path component. Here, the “sheet material” that constitutes the laminate
Includes not only a sheet-shaped sheet material and a plate material, but also a separator forming member formed to be a mirror image.

In the method of manufacturing a separator according to the present invention, in the film forming step, the gas containing the paint in the form of a mist is caused to flow down to the flow path of the laminate so that the hydrophilic surface is formed on the surface of the flow path constituting portion. The step may be a step of forming a film made of a material exhibiting the following. This makes it possible to easily adjust the thickness of the coating made of a material exhibiting hydrophilicity by adjusting the amount of flowing gas and the flowing time. In addition, the flow of the gas containing the atomized paint into the flow path is the same as the flow of the fuel into the flow path, so that a film having a thickness corresponding to the flow of the fuel into the flow path can be formed. That is, since a thicker film can be formed in a portion where the flow rate of the fuel is slow, a separator can be manufactured which can quickly discharge water in a portion where the flow rate of the fuel is low and water is easily accumulated.

[0013] The separator of the present invention is laminated with a power generation layer comprising an electrolyte membrane and two electrodes sandwiching the electrolyte membrane, forms a partition between the power generation layers, and when laminated, acts as an electrode of the power generation layer. A fuel cell separator that forms a flow path for supplying fuel, which is formed of a material exhibiting hydrophilicity on a surface on which the flow path is formed, and has a flow velocity of the fuel when the fuel flows through the flow path. The gist of the present invention is to provide a film having an appropriate thickness.

According to the separator of the present invention, a water-producing film having a hydrophilic property and a thickness corresponding to the flow rate of the fuel can be quickly discharged. In particular, since the flow rate of the fuel is an index of the easiness of water accumulation, it is possible to more quickly discharge water in a portion where water easily accumulates by setting the thickness of the film according to the flow rate of the fuel. .

In the separator according to the present invention, the coating may be formed so that a portion where the flow rate of the fuel is low is thick and a portion where the flow rate of the fuel is high is thin. This makes it possible to more quickly discharge the water at a portion where the flow rate of the fuel is low and the water easily accumulates.

According to the method of manufacturing a fuel cell of the present invention, a power generation layer including an electrolyte membrane and two electrodes sandwiching the electrolyte membrane, a partition between the power generation layers, and supplying fuel to the electrodes of the power generation layer A conductive separator that forms a flow channel, and a conductive separator that is disposed between the separator and the power generation layer and that supplies fuel to the electrode of the power generation layer by diffusing fuel supplied from the flow channel formed by the separator. A method of manufacturing a fuel cell, comprising: stacking a conductive fuel diffusion member and a fuel diffusion member, comprising: a power generation layer forming step of forming the power generation layer; a fuel diffusion member forming step of forming the fuel diffusion member; A separator forming member forming step of forming a separator forming member having a flow path constituent portion to be formed, and a laminate forming step of laminating the formed power generation layer, fuel diffusion member and separator forming member to form a laminate. And a hydrophilic part forming step of causing a paint containing a material exhibiting hydrophilicity to flow down into the flow path of the formed laminate to form a hydrophilic part using the material exhibiting hydrophilicity at a site where the flow path is formed. The gist is to provide

According to the fuel cell manufacturing method of the present invention, a paint containing a material exhibiting hydrophilicity flows down into a flow path formed in a laminated body in which a power generation layer, a fuel diffusion member, and a separator forming member are laminated. By doing so, a hydrophilic portion made of a material exhibiting hydrophilicity can be easily formed at a portion where a flow path is formed. Note that the power generation layer forming step, the fuel diffusion member forming step, and the separator forming member forming step in the method for manufacturing a fuel cell of the present invention are steps in no particular order, and any of the steps may be performed first, or at the same time, in parallel. It may be done by doing.

In the method of manufacturing a fuel cell according to the present invention, the step of forming the hydrophilic portion includes the step of flowing the mist-containing gas containing the paint into the flow path of the laminate to form the flow path at a portion where the flow path is formed. It may be a step of forming a hydrophilic part. In this case, the thickness of the hydrophilic portion made of a material exhibiting hydrophilicity can be easily adjusted by adjusting the amount of flowing gas and the flowing time. In addition, the flow of the gas containing the atomized paint into the flow path is the same as the flow of the fuel into the flow path, so that a hydrophilic portion having a thickness corresponding to the flow of the fuel into the flow path can be formed. . That is, since a thicker hydrophilic portion can be formed in a portion where the flow rate of the fuel is slower, a fuel cell which can quickly discharge water in a portion where the flow rate of the fuel is slower and water is easily accumulated can be manufactured.

The fuel cell of the present invention comprises an electrolyte membrane, two electrodes forming a power generation layer with the electrolyte membrane sandwiching the electrolyte membrane, a partition between the power generation layers, and an electrode of the power generation layer. A conductive separator that forms a flow path for supplying fuel to the fuel cell, and a separator that is disposed between the separator and the power generation layer, forms the flow path with the separator, and is supplied from the formed flow path. A fuel cell formed by stacking a conductive fuel diffusion member for diffusing fuel and supplying the fuel to an electrode of the power generation layer, wherein the separator has a film formed of a material exhibiting hydrophilicity. The fuel diffusion member is provided on a surface of a portion where a flow path is formed, and the fuel diffusion member has a hydrophilic portion formed of a material exhibiting hydrophilicity at a portion of the fuel diffusion member where the flow channel is formed.

According to the fuel cell of the present invention, the separator has a film formed of a material exhibiting hydrophilicity on the surface of the portion forming the flow path, and the fuel diffusion member is formed of a material exhibiting hydrophilicity. Since the formed hydrophilic portion is provided at a portion forming the flow channel, water generated in the flow channel can be quickly discharged. In addition, since a portion of the fuel diffusion member that forms the flow path has a hydrophilic portion, a small amount of water can be retained here, and the moisture retention of the electrolyte membrane can be improved.

[0021]

Next, embodiments of the present invention will be described with reference to examples. First, a fuel cell separator 20 according to an embodiment of the present invention and a method for manufacturing the same will be described. FIG. 1 is a process diagram showing an outline of a manufacturing process of the separator 20 of the embodiment, and FIG. 2 is an exploded perspective view when a separator forming member 22 and a sheet material 32 constituting the separator 20 are laminated.

In the manufacture of the separator 20, first, a step of forming the separator forming member 22 from dense carbon which is compressed and densified by carbon and gas-impermeable is performed (step S10). As shown in FIG. 2, the separator forming member 22 has through holes for forming a manifold for inflow and outflow of a fuel gas containing hydrogen gas and an oxidizing gas containing oxygen when laminated at four corners thereof. 23 to 26 are formed, and a serpentine groove 27 that connects the through hole 23 and the through hole 24 is formed on the display surface of FIG. Although not shown, the back surface of the separator forming member 22 in FIG.
A serpentine groove 28 communicating between the through hole 25 and the through hole 26 is formed in the same manner as the display surface of FIG.

Next, the formed separator forming member 22
And the sheet material 32 are alternately laminated to assemble the laminate 40 (step S12). Here, the sheet material 32 is formed of resin, and as shown in FIG. 2, through holes 33 to 36 matching the through holes 23 to 26 of the separator forming member 22 when laminated with the separator forming member 22 at four corners thereof. To form In the embodiment, the sheet material 32 is formed of a resin, but may be formed of any material such as metal or wood as long as the material is not affected by a hydrophilic paint described later or a carrier gas thereof. FIG. 3 is an external perspective view illustrating the external appearance of the laminate 40. As shown in the figure, the laminated body 40 is configured by arranging end plates 42 at both laminated ends of the separator forming member 22 and the sheet material 32 which are alternately laminated, and lightly tightening between the both end plates 42 with bolts 48. By tightening with the bolts 48 in this manner, an appropriate surface pressure can be applied between the separator forming member 22 and the sheet material 32. In the end plate 42, a through hole 43 and a through hole 46 that match the through hole 23 and the through hole 26 of the separator forming member 22 when attached are formed. Similarly, through holes 43 and 46 are formed in the end plate 42 disposed on the right side in FIG.
And the through hole 46 is formed in the through hole 2 of the separator forming member 22.
8 and the through-hole 24.

When the laminate 40 is assembled in this manner, two flow paths are formed in the laminate 40. One of them passes through the groove 27 of each separator forming member 22 from the through hole 43 of the end plate 42 through the through hole 23 of the separator forming member 22 and the through hole 33 of the sheet material 32, and further passes through the through hole of the separator forming member 22. 3 and a flow path reaching the through hole 46 of the other end plate 42 through the through hole 34 of the sheet material 32, and the other from the through hole 43 of the end plate 42 disposed on the right side in FIG. 2 through the through-hole 25 of the separator member 22 and the through-hole 35 of the sheet material 32, and further passes through the through-hole 26 and the sheet material 32 of the separator forming member 22. This is a flow path that reaches the through hole 46 of the end plate 42 disposed on the left side in FIG.

Subsequently, a material exhibiting hydrophilicity (for example, polyacrylamide, phosphoric acid chromate, silicon oxide, etc.) is formed in the two flow paths formed in the assembled laminated body 40.
Gas containing a paint containing mist in a mist state (step S1)
4). Although air was used as the carrier gas in the embodiment,
Any gas may be used. Then, the laminate 40 is dried (step S16), and the laminated body 40 is disassembled to take out the completed separator 20 (step S18).

FIG. 4 illustrates a part of a cross section of the separator 20 thus manufactured. As shown in FIG.
A hydrophilic coating 2 made of a material exhibiting hydrophilicity is provided on the surface of the portion where the above-mentioned flow path is formed from the groove 3 to the groove 27.
9 are formed. Since the hydrophilic coating 29 is formed by flowing the gas containing the mist-like paint down to the flow path formed in the laminate 40, a portion where the gas flow rate is low, for example, the serpentine groove 27 or the groove 28 The paint stagnates at the corners of the bent portion of the film and the thickness thereof becomes thicker than other portions.
Since these parts are the parts where gas easily stays,
When a fuel cell is constructed, water generated by the reaction of the above formula (2) or water generated by dew condensation is likely to accumulate. In the separator 20 of the embodiment, a thick hydrophilic film 29 is formed at this position. By doing so, the water that accumulates in this portion can be quickly discharged. In addition, the separator 20 of the example is the separator forming member 2.
Since the gas was caused to flow down into the flow path formed in the laminate 40 in which the sheet material 32 and the sheet material 32 were laminated to form the hydrophilic film 29,
The hydrophilic film 29 is formed only on the inner wall surfaces of the grooves 27 and 28 and the inner wall surfaces of the through holes 23 to 26, and is provided on the contact surface of the separator 20 with the electrode (the contact surface of the separator forming member 22 with the sheet material 32). No hydrophilic coating 29 is formed. As a result, an increase in contact resistance due to the formation of the hydrophilic coating 29 on the contact surface of the separator 20 can be prevented.

According to the method of manufacturing the separator 20 of the embodiment described above, the hydrophilic film 29 can be easily formed on the inner wall surface of the groove 27 or the groove 28 forming the flow path of the fuel gas or the oxidizing gas. . A method of manufacturing the separator 20 by completing the separator 20 by spraying a paint of a material exhibiting hydrophilicity by masking portions other than the inner wall surfaces of the grooves 27 and 28 and then removing the mask, or by dipping the entire separator forming member 22 in the paint exhibiting hydrophilicity To form a hydrophilic coating on the entire separator forming member 22, and remove the hydrophilic coating on other portions by polishing or the like except for the hydrophilic coating 29 on the inner wall surfaces of the grooves 27 and 28, thereby completing the separator 20. The separator 20 can be manufactured very easily as compared with a manufacturing method or the like. In addition, the hydrophilic coating 29 can be formed thicker at portions where water easily accumulates and thinner at other portions. As a result, the produced separator 20 can discharge water generated in a portion where water easily accumulates more quickly. Of course,
In the manufactured separator 20, since the hydrophilic film 29 is formed on the inner wall surfaces of the grooves 27 and the grooves 28, water generated by the reaction of the above formula (2) and water generated by dew condensation are quickly discharged. The fuel gas and the oxidizing gas can be smoothly supplied to the electrode. Further, since the hydrophilic film 29 is not formed on the contact surface of the separator 20 with the electrode, high conductivity can be maintained.

In the separator 20 of the embodiment, the flow paths of the fuel gas and the oxidizing gas are formed by the serpentine grooves 27 and the grooves 28, but the separator 20B of the modified example illustrated in FIG.
As shown in (1), the flow path 27B may be formed by forming a plurality of protrusions 27A on the surface. In this case, the hydrophilic film 29B is formed between the side wall surface of the protrusion 27A and the flow path 2.
7B is formed on the wall surface. Also in this case, the hydrophilic coating 29B
Is formed in accordance with the gas flow velocity, the surface of the convex portion 27A on the side of the through hole 23B where the gas flow velocity is slow and the opposite surface are formed thick, and the other side surface of the convex portion 27A is formed thin. The separator 20B of this modification also has the same effect as the separator 20 of the embodiment.

In the manufacturing method of the separator 20 of the embodiment,
Although the separator 40 is assembled by alternately laminating the separator forming members 22 and the sheet material 32, when the separator is bilaterally symmetrical and mirror-image like the separator 20B of the modified example of FIG. May be used, and only the separator may be laminated to assemble the laminate. In this case, since the sheet material 32 is not required, the separator can be manufactured more easily.

In the manufacturing method of the separator 20 of the embodiment,
A gas containing a paint made of a material exhibiting hydrophilicity in the form of a mist flows down the flow path formed in the laminate 40 to form the hydrophilic film 29. However, the flow path formed in the laminate 40 exhibits hydrophilicity. The hydrophilic coating 29 may be formed by directly flowing down a coating material.

In the separator 20 of the embodiment, the separator forming member 22 is formed of dense carbon. However, any material having conductivity and gas impermeability can be used to form the separator forming member 22.

Next, a fuel cell 110 according to a second embodiment of the present invention and a method for manufacturing the same will be described. FIG. 6 is a process diagram showing an outline of a manufacturing process of the fuel cell 110 according to the embodiment.
FIG. 7 shows a separator forming member 1 constituting the fuel cell 110.
FIG. 8 is an exploded perspective view of the stacking of the fuel cell 110, the power generation layer 131, and the gas diffusion electrode 142.

The manufacture of the fuel cell 110 of the embodiment is as follows.
The process starts with the step of forming the power generation layer 131, the gas diffusion electrode 142, and the separator forming member 122 (steps S20, S
22, S24). These three steps are steps in any order, and any of the steps may be performed first, or all the steps may be performed simultaneously in parallel.

The power generation layer 131 includes an electrolyte membrane 132 and two electrodes 137 and 138 sandwiching the electrolyte membrane 132.
The electrolyte membrane 132 is formed of an ion exchange membrane formed of a polymer material, for example, a fluorine-based resin and having a good electrical conductivity in a wet state of 100 μm to 200 μm in thickness. At four corners of the electrolyte membrane 132, as shown in FIG. 7, through holes 133 to 133 for forming manifolds for inflow and outflow of fuel gas or oxidizing gas when stacked.
36 is formed. The two electrodes 137 and 138 are formed by printing, on the surface of the electrolyte membrane 132, carbon particles carrying platinum as a catalyst or an alloy of platinum and another metal on the surface.

The gas diffusion electrode 142 is formed of a carbon cloth woven from carbon fiber yarn. As shown in FIG. 7, the electrolyte membrane 13 is also provided at the four corners of the gas diffusion electrode 142.
Through holes 143 to 146 are formed to match the through holes 133 to 136 formed at the four corners of No. 2. Separator forming member 1
22 is formed of the same material and in the same shape as the separator forming member 22 constituting the separator 20 of the above-described embodiment, so that further description is omitted.

Next, the power generation layer 131, the gas diffusion electrode 142, and the separator formation member 122 thus formed are combined with the separator formation member 122, the gas diffusion electrode 142, the power generation layer 131, the gas diffusion electrode 142, and the separator formation member 12.
2 and the laminated body 140 is assembled (step S2).
6). This stacked body 140 is similar in appearance to the fuel cell 110 shown in FIG. 8, and similarly to the above-described stacked body 40, end plates 152 are attached to both stacked ends thereof, and the bolt 1
It is configured by tightening at 58. The end plate 152 has the same separator forming member 1 as the end plate 42.
A through hole 153 and a through hole 156 aligned with the through hole 123 and the through hole 126 of FIG. 22 are formed, and the end plate 152 on the left side in FIG. 8 is formed by the through hole 153 and the through hole 156 of the separator forming member 122. And through hole 1
The end plate 152 on the right side in FIG. 8 is provided with through holes 153 and 156.
Are attached so as to match the through holes 125 and 124 of the separator forming member 122, respectively.
40. When the laminated body 140 is assembled in this manner, two flow paths are formed in the laminated body 140 in the same manner as the above-described laminated body 40.

Subsequently, a gas containing a paint containing a hydrophilic material is sprayed through the two flow paths formed in the assembled laminate 140 (step S28) and dried (step S30). ), To complete the fuel cell 110. Materials and gases exhibiting hydrophilicity are the same as those described in the method of manufacturing the separator 20 described above.

FIG. 9 illustrates a part of a cross section of the fuel cell 110 manufactured as described above. As shown in FIG. 9, a hydrophilic film 129 made of a material exhibiting hydrophilicity is formed on the inner wall surfaces of the grooves 127 and 128 of the separator forming member 122, and the grooves 127 and the grooves of the gas diffusion electrode 142 are formed. 1
A hydrophilic portion 129B made of a material exhibiting hydrophilicity is formed at a portion where a flow path is formed by the flow path 28 and the flow path. Since the gas diffusion electrode 142 is formed of carbon cloth, the hydrophilic portion 129B does not become a film covering the entire surface thereof, but is formed by adhering to the surface of the carbon cloth fiber. Therefore, the gas diffusion electrode 14
The diffusivity of the second gas is not impaired. In addition, the hydrophilic part 129
B has a moisturizing property because it is formed of a material exhibiting hydrophilicity. As a result, drying of the power generation layer 131 can be prevented.

Further, similarly to the method of manufacturing the separator 20 of the embodiment, the hydrophilic film 129 and the hydrophilic portion 129B are formed by flowing a gas containing a mist-like paint into the flow path formed in the laminate 140. Therefore, the thickness of the hydrophilic coating 129 and the hydrophilic portion 129B at a portion where the gas flow rate is slow can be made larger than other portions. As a result, it is possible to quickly discharge water in a portion where gas easily stays and water easily accumulates. Note that the fuel cell 110 of the embodiment is
The gas is caused to flow down the flow path formed in the hydrophilic coating 12.
9 and the hydrophilic portion 129B, the through holes 123 to 126 of the separator forming member 122 and the gas diffusion electrode 142 are formed.
Through-holes 143 to 146 of the electrolyte membrane 132
A hydrophilic coating 129 is also formed on the inner wall surfaces of 3-136. Similarly to the separator 20, the inner wall surfaces of the grooves 127 and the grooves 128 of the separator forming member 122 and the through holes 123 are formed.
A hydrophilic coating 129 is formed only on the inner wall surfaces of
No hydrophilic coating 129 or hydrophilic portion 129B is formed on the contact surface of the separator forming member 122 with the electrode (the contact surface of the separator forming member 122 with the gas diffusion electrode 142).
As a result, the separator forming member 122 and the gas diffusion electrode 1
Good conductivity can be ensured between the first conductive material and the second conductive material.

According to the method of manufacturing the fuel cell 110 of the embodiment described above, the hydrophilic film 129 is easily formed on the inner wall surfaces of the grooves 127 and 128 forming the flow paths of the fuel gas and the oxidizing gas.
Can be formed. The fuel cell 110 can be manufactured extremely easily as compared with the case where a fuel cell is assembled using a separator in which the hydrophilic film 129 is formed on the inner wall surface of the groove 127 or the groove 128 in advance. In addition, since the hydrophilic portion 129B is formed at a position where the flow path is formed by the groove 127 and the groove 128 of the gas diffusion electrode 142, the gas diffusion electrode 142 having moisture retention can be formed. As a result, the power generation layer 131 can be prevented from drying.

According to the fuel cell 110 of the embodiment,
Since the hydrophilic film 129 and the hydrophilic portion 129B are formed thick in portions where water easily accumulates and thin in other portions, water generated in portions where water easily accumulates can be discharged more quickly. Naturally, since the fuel cell 110 has the hydrophilic coating 129 formed on the inner wall surface of the groove 127 or the groove 128, the water generated by the reaction of the above formula (2) and the water generated by the condensation are quickly discharged. The fuel gas and the oxidizing gas can be smoothly supplied to the electrode.
Further, the gas diffusion electrode 142 of the separator forming member 122
Since the hydrophilic film 129 and the hydrophilic portion 129B are not formed on the contact surface with the substrate, high conductivity can be maintained.

In the fuel cell 110 of the embodiment, the separator forming member 122 in which the flow path of the fuel gas or the oxidizing gas is formed by the serpentine groove 127 or the groove 128 is used, but the separator 20B of the modified example illustrated in FIG. May be used. In the fuel cell 110 of the embodiment, the separator forming member 122 made of dense carbon is used. However, a separator forming member made of any material having conductivity and gas impermeability may be used. .

In the method of manufacturing the fuel cell 110 of the embodiment,
A gas containing a paint made of a material exhibiting hydrophilicity in the form of a mist is caused to flow down the flow path formed in the laminate 140 to form a hydrophilic film 129.
Although the hydrophilic portion 129B is formed, a coating made of a material exhibiting hydrophilicity may directly flow down into the flow path formed in the laminate 140 to form the hydrophilic film 129 and the hydrophilic portion 129B.

The embodiments of the present invention have been described with reference to the embodiments. However, the present invention is not limited to these embodiments, and various embodiments may be made without departing from the gist of the present invention. Of course, it can be carried out.

[Brief description of the drawings]

FIG. 1 is a manufacturing process diagram schematically showing a manufacturing process of a separator 20 according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view when a separator forming member 22 and a sheet material 32 constituting the separator 20 of the embodiment are stacked.

FIG. 3 is an external perspective view illustrating the external appearance of a laminate 40.

FIG. 4 is a partial cross-sectional view illustrating a part of the cross section of the separator 20 of the embodiment.

FIG. 5 is a partial cross-sectional view showing a part of a cross section of a separator 20B of a modified example.

FIG. 6 is a manufacturing process diagram schematically showing a manufacturing process of a fuel cell 110 according to one embodiment of the present invention.

FIG. 7 shows a separator forming member 122, a power generation layer 131, and a gas diffusion electrode 142 that constitute the fuel cell 110 of the embodiment.
FIG. 4 is an exploded perspective view when laminating the layers.

FIG. 8 is a schematic perspective view of a fuel cell 110 according to an embodiment.

FIG. 9 is a partial cross-sectional view illustrating a part of the cross section of the fuel cell 110 of the embodiment.

[Explanation of symbols]

20 separator, 22 separator forming member, 23-
26 through hole, 27, 28 groove, 29 hydrophilic coating, 3
2 sheet material, 33-36 through-hole, 40,140 laminated body, 42 end plate, 43,46 through-hole, 4
8 bolt, 20B separator, 23B, 25B through hole, 27A convex portion, 27B channel, 29B hydrophilic coating, 110 fuel cell, 122 separator forming member,
123-126 Through holes, 127, 128 Grooves, 129
Hydrophilic film, 129B hydrophilic part, 131 power generation layer, 1
32 electrolyte membrane, 133-136 through hole, 137,1
38 electrodes, 142 gas diffusion electrodes, 143-146
Through hole, 152 End plate, 153, 156 Through hole, 158 volts.

Claims (7)

[Claims] 1. A power generation layer comprising an electrolyte membrane and two electrodes sandwiching the electrolyte membrane are stacked together to form a partition between the power generation layers, and when stacked, supply fuel to the electrodes of the power generation layer. A method for manufacturing a separator for a fuel cell that forms a flow path, comprising: a forming member forming step of forming a separator forming member having a flow path constituent portion that forms the flow path; and forming the formed separator forming member into a sheet. A laminate forming step of laminating with a material to form a laminate, and causing a paint containing a material exhibiting hydrophilicity to flow down into the flow path of the formed laminate to form a hydrophilic layer on the surface of the flow path forming portion. A film forming step of forming a film made of a material exhibiting properties. 2. The film forming step includes forming a film made of the hydrophilic material on the surface of the flow path component by flowing a mist-containing gas containing the paint into the flow path of the laminate. The method for producing a separator according to claim 1, which is a step. 3. A power generation layer comprising an electrolyte membrane and two electrodes sandwiching the electrolyte membrane. The power generation layer is laminated to form a partition between the power generation layers. When the power generation layer is laminated, fuel is supplied to the electrodes of the power generation layer. A separator for a fuel cell forming a flow path, wherein the surface forming the flow path is formed of a material exhibiting hydrophilicity, and has a thickness according to a flow rate of the fuel when the fuel flows through the flow path. A separator comprising a coating having: 4. The separator according to claim 3, wherein the coating is formed thick at a portion where the flow rate of the fuel is low and thin at a portion where the flow rate of the fuel is high. 5. A power generation layer comprising an electrolyte membrane and two electrodes sandwiching the electrolyte membrane, and a conductive layer forming a partition between the power generation layers and forming a flow path for supplying fuel to the electrodes of the power generation layer. A separator, and a conductive fuel diffusion member that is disposed between the separator and the power generation layer and that diffuses fuel supplied from the flow path formed by the separator and supplies the fuel to the electrode of the power generation layer. A method of manufacturing a fuel cell, comprising: a power generation layer forming step of forming the power generation layer; a fuel diffusion member forming step of forming the fuel diffusion member; and a flow path constituting part of the flow path. A separator forming member forming step of forming a separator forming member; a laminate forming step of laminating the formed power generation layer, the fuel diffusion member and the separator forming member to form a laminate; Method for manufacturing a fuel cell and a hydrophilic portion forming step of forming a hydrophilic portion by material a paint containing a material exhibiting hydrophilicity to the serial flow path by flow down exhibits the hydrophilic portion forming the flow path. 6. The hydrophilic part forming step is a step of forming the hydrophilic part in a portion where the flow path is formed by flowing a mist-containing gas containing the paint into the flow path of the laminate. Item 6. The method for producing a fuel cell according to Item 5. 7. An electrolyte membrane, two electrodes forming a power generation layer with the electrolyte membrane sandwiching the electrolyte membrane, forming a partition between the power generation layers, and supplying fuel to the electrodes of the power generation layers. A conductive separator that forms a flow path, disposed between the separator and the power generation layer, forms the flow path with the separator, and diffuses fuel supplied from the formed flow path. A fuel cell formed by laminating a conductive fuel diffusion member to be supplied to an electrode of the power generation layer, wherein the separator forms a film formed of a material having hydrophilicity to form the flow path of the separator. A fuel cell having a surface of a portion, wherein the fuel diffusion member has a hydrophilic portion formed of a material exhibiting hydrophilicity at a portion of the fuel diffusion member that forms the flow path.