JP2007242443A - Fuel cell power generation cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell power generation cell capable of suppressing retention of liquid water or the like to the interior of a gas diffusion layer in a fuel cell stack, and of suppressing closing of pores of the gas diffusion layer surface. <P>SOLUTION: This is the fuel cell power generating cell provided with the gas diffusion layer 2 that is a porous body in which water-repellency treatment, oil-repellency treatment, or hydrophilic treatment is applied, and in which a tube part 6 of which the vertical sectional face has a taper shape is formed. The tapered tube parts are formed in a plurality of numbers and a cross section change rate in the longitudinal direction of these are uneven. The tapered tube parts compose an aggregate, and the other tapered tube parts are peripherally installed so that the radius of the tapered tube parts becomes smaller as they are separated from the tapered tube part at the center. The neighboring tapered tube parts are mutually communicated by flow passages. The tapered tube parts are formed by a dissipating type. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel cell power generation cell, and more particularly to a fuel cell power generation cell that can efficiently guide liquid water that convects in a gas diffusion layer when stacked and can always operate stably. .

A fuel cell system is a device that directly converts chemical energy of fuel into electrical energy, and supplies a fuel gas containing hydrogen to an anode of a pair of electrodes provided with an electrolyte membrane interposed therebetween, and the other cathode An oxygen agent gas containing oxygen is supplied to the electrodes, and electric energy is extracted from the electrodes by using the following electrochemical reaction that occurs on the surface of the pair of electrodes on the electrolyte membrane side (see, for example, Patent Document 1).
JP-A-8-106914

Anode reaction: H ₂ → 2H ⁺ + 2e ⁻ (1)
Cathode reaction: 2H ⁺ + 2e ⁻ + (1/2) O ₂ → H ₂ O (2)

Here, as a method of supplying the fuel gas to the anode, a method of supplying directly from a hydrogen storage device, a method of supplying a reformed hydrogen-containing gas by reforming a fuel containing hydrogen, and the like are known. Examples of the hydrogen storage device include a high-pressure gas tank, a liquefied hydrogen tank, a hydrogen storage alloy tank, and the like, and natural gas, methanol, gasoline, and the like can be considered as the hydrogen-containing fuel.
Further, oxygen in the air is generally used as the oxidant gas supplied to the cathode.

When power is generated by the fuel cell system, water is inevitably generated as shown on the right side of the above equation (2). This water is generated as gas or liquid depending on the surrounding environment of the power generation site.
For example, when a fuel cell system is used as a power source for an automobile, the inside of the gas diffusion layer on the oxidant gas side under operating conditions such as a cell temperature of 40 ° C. or lower, a low gas flow rate, and a pressure of about 2 atmospheres It has been confirmed from observational experiments that water vapor changes phase to liquid water and passes through the space in the gas diffusion layer to generate a large number of water droplets on the surface.

When the amount of generated water droplets is large, liquid water occupies the space inside the gas diffusion layer, and the oxidant gas cannot reach the power generation surface inside the power generation cell, so that a so-called flooding phenomenon occurs.
When this flooding phenomenon occurs, the voltage drops, and as a result, power generation becomes impossible, and an application using this as a power source becomes inoperable.

For this reason, it has been proposed to discharge liquid water by laminating one or more layers of a porous and film-like thermosetting resin that has been subjected to hydrophilic treatment or water repellency treatment (for example, Patent Documents). 2).
JP 2004-288400 A

However, in the technique described in Patent Document 2, a layered resin film is laminated together with a fuel cell stack. However, since the resin film has low electrical conductivity, the cell voltage is lowered. For this reason, it is a resistor that becomes an obstruction, and under the operating conditions that do not cause flooding, the diffusion and flow of fuel gas and oxidant gas are hindered, which has an adverse effect.
In addition, the hydrophilicity is uniform within the laminated surface, and the generated liquid water covers the resin film surface uniformly, resulting in the formation of a liquid film so as to cover the surface of the gas diffusion layer, and the flow of gas The power generation performance was not necessarily improved.

  The present invention has been made in view of such problems of the prior art, and the object of the present invention is to suppress the retention of liquid water or the like inside the gas diffusion layer in the fuel cell stack, An object of the present invention is to provide a fuel cell power generation cell capable of suppressing pore blockage on the surface of a diffusion layer.

  As a result of intensive studies to solve the above problems, the present inventor has found that the above problems can be solved by using a porous body having a tapered tube portion as a gas diffusion layer, thereby completing the present invention. It came to.

  That is, the fuel cell power generation cell of the present invention is a fuel cell power generation cell comprising a gas diffusion layer, wherein the gas diffusion layer is a porous body that has been subjected to water-repellent treatment, oil-repellent treatment, or hydrophilic treatment. A tube portion having a tapered longitudinal section is formed inside the body.

  Moreover, the suitable form of the fuel cell power generation cell of the present invention is characterized in that a plurality of the tapered tube portions are formed, and the rate of change in cross section in the longitudinal direction is not uniform.

  Furthermore, another preferred embodiment of the fuel cell power generation cell of the present invention is characterized in that the gas diffusion layer has a plurality of tapered tube portions, and the adjacent tapered tube portions communicate with each other through a flow path. To do.

  Furthermore, still another preferred embodiment of the fuel cell power generation cell of the present invention is characterized in that the tapered tube portion of the gas diffusion layer is formed of a disappearing type.

  According to the present invention, since the porous body in which the tapered tube portion is formed is used as the gas diffusion layer, it is possible to suppress liquid water and the like from staying inside the gas diffusion layer in the fuel cell stack, It is possible to provide a fuel cell power generation cell capable of suppressing surface hole blockage.

  Hereinafter, the fuel cell power generation cell of the present invention will be described in detail. In the present specification and claims, “%” indicates a mass percentage unless otherwise specified.

As described above, the fuel cell power generation cell of the present invention includes a gas diffusion layer (GDL), and this gas diffusion layer is made of a porous body that has been subjected to water-repellent treatment, oil-repellent treatment, or hydrophilic treatment. Further, a tube portion having a tapered longitudinal section is formed inside the porous body.
The longitudinal section shows a longitudinal section of the tapered tube portion, and the sectional shape of the tapered tube portion is limited to a circle as long as the sectional area decreases from one end to the other end. It is not something.

With such a configuration, when the gas diffusion layer is water-repellent or oil-repellent, liquid such as water or oil scattered in the space in the gas diffusion layer collects the surface tension of the droplets to be aggregated. By this, it moves from the space in the fine gas diffusion layer to the wide space of the tapered tube portion. For this reason, the fine space in the gas diffusion layer is empty, so that it is possible to prevent the gas from flowing.
In addition, since the space wider than the pores of the porous body has a tapered shape, the water or oil that adheres so as to block the cross section of a part of the flow path due to the surface tension of the droplet itself is tapered tube section The wide side and the narrow side are seated so that the radius of the liquid interface shape is different. At this time, since the radius is different, a pressure difference is generated, so that the gas moves to a lower pressure side and is discharged from the gas diffusion layer.
In this way, power generation at a high load operation with a large amount of water generated or at a temperature lower than the saturation temperature can be maintained.

  On the other hand, when the gas diffusion layer is hydrophilic, liquid water penetrates into the porous space of the gas diffusion layer without staying in the flow path in the gas diffusion layer. Thereby, since it becomes a wet mechanism in the location where water runs short, the power generation under the condition that it is easy to dry is suppressed.

Here, it is preferable to form a plurality of the tapered tube portions so that the rate of change in the cross section in the longitudinal direction is not uniform. In other words, the continuous cross-sectional area change rate of the tapered tube portion provided in the gas diffusion layer, that is, the taper angle can be varied for each tapered tube portion.
Thereby, the moving speed of liquid water etc. can be changed and it becomes possible to set desired drainage performance.
In addition, the cross section of a taper-shaped pipe part means the cross section of the taper-shaped pipe part which appears in the cross section (horizontal cross section) of the extending direction of a gas diffusion layer. Further, the term “non-uniform” means that adjacent tapered tube portions need only have different cross-sectional change rate shapes, and that means that all tapered tube portions have different cross-sectional change rate shapes. is not.

It is preferable that a plurality of tapered pipe portions form an aggregate (colony state) inside the porous body serving as the gas diffusion layer.
Specifically, as the radius of the tapered tube portion decreases as the distance from the tapered tube portion at the center of the aggregate increases, the other tapered tube portion can be provided around. Here, the radius indicates the radius of the opening on the same surface (front surface or back surface) of the gas diffusion layer or the radius of the opening formed in the horizontal section of the gas diffusion layer.
Further, as the distance from the tapered tube portion at the center of the aggregate increases, another tapered tube portion can be provided so as to reduce the rate of change in cross section.

As a result, in one aggregate, a tapered tube portion having a small flow channel radius is formed around the tapered tube portion having a large flow channel radius. Liquid water or the like can be moved to the center, and movement of the liquid water or the like can be controlled over a wider range, so that it is possible to generate power under a condition where the amount of liquid water generated is larger.
One or a plurality of aggregates of tapered tube portions can be formed in any part of the gas diffusion layer according to the size, shape, type of porous body, and the like of the fuel cell power generation cell.

Moreover, when forming a some taper-shaped pipe part in the said gas diffusion layer, it is suitable to make adjacent taper-shaped pipe parts communicate with each other by the flow path.
At this time, the generated liquid water or the like not only moves to the nearby tapered tube portion through the pores of the gas diffusion layer, but also the tapered tube portion in the gas diffusion layer is moved in the in-plane direction by the flow path. Since it is connected, it can be easily moved to a tapered tube portion having a large radius and a low pressure. In other words, liquid water or the like can move from a tapered tube portion having a relatively small channel diameter to a tapered tube portion having a relatively large channel diameter to a tapered tube portion having a wider space. . As a result, since the liquid can be condensed and discharged, power generation under a condition where the amount of liquid water generated is large can be maintained.

Furthermore, it is preferable that the flow path for communicating the tapered tube portion is tapered and has a terminal portion.
By making the flow path into a tapered shape, the direction of liquid water or the like that moves from the tapered tube portion to the tapered tube portion can be controlled. Further, by allowing the terminal portion to be present inside the porous body other than the tapered tube portion, more liquid water or the like that moves in the in-plane direction can be secured. Thereby, the collection amount of liquid water etc. increases and it becomes possible to generate electric power under more difficult conditions.

In the fuel cell power generation cell of the present invention, the gas diffusion layer can be disposed on one or both of the cathode electrode side and the anode electrode side.
At this time, it is preferable that the gas diffusion layer disposed on the cathode electrode side communicates with the tapered tube portion while expanding from the power generation surface side to the gas channel side. As a result, the function of collecting and discharging liquid water at the cathode electrode where liquid water generation is likely to occur can be provided, so that power generation under difficult conditions with a large amount of liquid water generation becomes possible.
Further, it is preferable that the gas diffusion layer disposed on the anode electrode side communicates with the tapered tube portion while expanding the diameter from the gas channel side to the power generation surface side. This provides a function to collect and discharge liquid water that has been liquefied in the gas diffusion layer when water vapor enters the anode electrode that is unlikely to generate liquid water, that is, the anode electrode that tends to dry, through the electrolyte membrane for some reason. Therefore, dryout at the anode electrode can be suppressed.

In the fuel cell power generation cell of the present invention, it is preferable that the tapered tube portion of the gas diffusion layer is formed by a disappearing type.
At this time, a porous body having a desired liquid water recovery / discharge function can be easily produced.

Moreover, as a porous body used as the said gas diffusion layer, the thing which concerns on carbon fiber, a silica, a titania, an alumina, a zirconia, a tantalum, and these arbitrary combinations can be used typically.
Further, the disappearing mold can be subjected to water repellent treatment, oil repellent treatment or hydrophilic treatment on the formed tapered tube portion by appropriately changing the material.
For example, when imparting water repellency and oil repellency, fluororesin such as polyethylene terephthalate (PTFE), a copolymer of tetrafluoroethylene and perfluoroalkoxyethylene, and HfO ₂ can be used. When imparting hydrophilicity, TiO ₂ , SiO ₂ , CeO ₃ or the like can be used.

  Hereinafter, although the embodiment of the fuel cell power generation cell of the present invention is further explained in detail based on a drawing, the present invention is not limited to these.

FIG. 1 shows an embodiment of a fuel cell power generation cell, which is one of the elements that make up the cell structure of a general fuel cell stack.
The fuel cell power generation cell is composed of a separator 1, a gas diffusion layer (GDL) 2, and a solid electrolyte membrane 3 on which a catalyst layer is installed. Of the concavo-convex shape of the separator 1, the concave portion is referred to as a channel 1 a through which fluid flows, and the convex portion is referred to as a rib or land portion 1 b.

FIG. 2 shows a longitudinal section of the first gas diffusion layer 2 that can be used in the fuel cell power generation cell of FIG.
The gas diffusion layer 2 has a tapered tube portion 6 inside. The tapered tube portion 6 becomes a flow path for some fluid and can be used for circulation thereof.

FIG. 3 shows a driving force for moving the droplet when the droplet exists in the tapered tube portion 6 in the gas diffusion layer 2 having water repellency with a contact angle of about 160 °.
As shown in the figure, the radius that forms the spherical surface of the droplet is determined from the geometric shape formed by the gas-liquid interface, upstream and downstream in the tapered tube section. At this time, the cross-sectional area of the flow path differs between the upstream and downstream, and a difference occurs in the radius of the spherical surface. The pressure on the respective surface liquid side is higher than the pressure of the surrounding gas by 2σ / r1 or 2σ / r2. That is, since the radius r1 of the upper surface is larger than r2, the magnitude relation of the pressure of the ambient gas <2σ / r1 <2σ / r2 appears, and as a result, the smaller pressure, that is, the larger radius side (FIG. 3). To the upper side).
This means that liquid water and the like scattered in the gas diffusion layer 2 will increase in volume due to condensation, and will move because they have a large contact angle from a narrow space to a wide space when they are connected to each other. It means that. If the gas diffusion layer 2 is a narrow space, the space formed by the tapered tube portion 6 can be considered to be sufficiently larger than the pore diameter of the gas diffusion layer 2, and the liquid in the pores is tapered tube portion. Move to 6. For this reason, it is possible to reverse the gas diffusion, which is only a slight decrease in the diffusivity in the movement of the gas in the pores, and the extreme diffusion resistance when liquid water etc. is present in the pores is large This means that the power generation of the fuel cell is performed better.
In the gas diffusion layer having hydrophilicity with a contact angle of about 5 °, the liquid droplet moves to the smaller radius, contrary to the case of water repellency.

  As described above, the tapered tube portion 6 formed in the gas diffusion layer 2 is formed by the dew condensation of the liquid water generated by the above equation (2) performed when the fuel cell generates power and the input steam for humidification. It can be used as a passage for liquid water or liquid water in which the vapor transferred from the anode side to the cathode side by diffusion has condensed. Further, the tapered tube portions 6 may be provided at regular intervals or at irregular intervals. Furthermore, it is desirable to install it appropriately according to the desired conditions and the amount of liquid water generated.

FIG. 4 is a longitudinal section of the second gas diffusion layer 2 that can be used in the fuel cell power generation cell of FIG.
The tapered tube portion 6 is provided at an angle with respect to the normal direction of the surface of the gas diffusion layer 2 facing the channel 1a.
In this case, when the oxidant gas or the fuel gas is circulated through the channel 1a, the flow rate of the gas increases when the tapered tube portion 6 is deflected in the flowing direction of the circulated gas on the channel surface of the gas diffusion layer 2. The pressure drops at the channel surface. For this reason, since the taper-shaped pipe part 6 to which liquid water etc. moves has an inclination, the pressure on the channel surface near the exit of the taper-like pipe part 6 falls, and movement of liquid water etc. is promoted. Drainage is possible.

FIG. 5 is a longitudinal section of the third gas diffusion layer 2 that can be used in the fuel cell power generation cell of FIG.
The tapered tube portion 6 is formed with a free depth with respect to the thickness direction of the gas diffusion layer 2. That is, the tapered tube portion 6 penetrating from the upper surface to the lower surface and the tapered tube portion 6 from the upper surface to the middle portion of the gas diffusion layer 2 are mixed.
In this case, the temperature becomes high during power generation by the fuel cell power generation cell, and water generated as vapor on the surface of the solid electrolyte membrane may be liquefied in the middle part of the gas diffusion layer 2 on the way to the channel 1a. The presence of the tapered tube portion 6 in the porous body facilitates liquefaction.
When water is not liquefied, the volume of the gas is 1000 times (1/1000 in density) than when it is liquid, so oxygen must be supplied for the oxidation of equation (2) above, but it occurs simultaneously. Since steam (water gas) and oxygen tend to flow in directions opposite to each other, supply of oxygen is likely to be hindered. For this reason, by forming the tapered tube portion 6 only in the vicinity where liquefaction is performed, the porous body portion can be left and active liquefaction can be achieved, and the water vapor gas can be prevented from preventing the oxidant gas from going up. .
The gas diffusion layer 2 having the tapered tube portion 6 as described above is formed by interposing a die in a tape-shaped male die which is a resin slurry-like object called carbon fiber and binder. Can be manufactured by firing. It can also be produced by placing the slurry on a substrate having a taper-shaped protrusion, and fixing and firing.

FIG. 6 is a longitudinal section of the fourth gas diffusion layer 2 that can be used in the fuel cell power generation cell of FIG.
The tapered tube portion 6 is formed in a free direction.
In this case, it is effective to smoothly move the liquid water generated under the rib 1b to the channel 1a.

FIG. 7 is a longitudinal section of a fifth gas diffusion layer 2 that can be used in the fuel cell power generation cell of FIG.
The tapered tube portion 6 is prepared in advance with a mesh-like object 7 and has a configuration in which the tapered tube portion 6 is disposed in the gas diffusion layer 2. The pore diameter of this mesh is preferably larger than the pore diameter of the gas diffusion layer 2 after firing. FIG. 8 is an enlarged view of the mesh-like object 7. The mesh-like object 7 can be produced by, for example, sputtering, fine fine wires coated with polyimide, or the like.

FIG. 9 is a longitudinal section of a sixth gas diffusion layer 2 that can be used in the fuel cell power generation cell of FIG.
The porous body that constitutes the gas diffusion layer 2 is made using fine particles called microbeads having a good particle size of about 0.01 μm to 0.1 mm. The microbeads can be produced, for example, by sputtering, fine fine wires coated with polyimide, or the like.
A porous body using microbeads can be prepared by laminating sheets using the microbeads. However, the tapered tube portion 6 is a particle of a hole that becomes a tapered tube portion 6 for each layer to be laminated. It can be formed by changing the diameter stepwise.

FIG. 10 is a longitudinal section of a seventh gas diffusion layer 2 that can be used in the fuel cell power generation cell of FIG.
The plurality of tapered pipe portions 6 communicate with each other through a flow path 8 formed in the plane of the gas diffusion layer 2. The number of the flow paths 8 that communicate with each other can be set regardless of the number of the tapered pipe sections 6. Desirably, it can be installed according to the location where the liquid water is frequently generated or generated.
In addition, when communicating by providing the flow path 8, as shown in FIG. 11, the liquid water etc. which were connected between the adjacent tapered pipe parts 6 have a difference in the average radius in the tapered pipe parts 6. In some cases, the small droplet 9 has a small radius and therefore a high pressure in the liquid, and the large droplet 10 has a large radius and the pressure is higher than the surroundings, but is relatively lower than the small droplet 9. For this reason, the small droplets 9 are gathered toward the large droplet 10 side.

FIG. 12 is a longitudinal section of an eighth gas diffusion layer 2 that can be used in the fuel cell power generation cell of FIG.
The taper angle of the plurality of tapered tube portions 6 is changed to change the average diameter. Since the flow path diameter of the tapered tube portion 6 is changed, it is possible to further draw out the action of the liquid water recovery / discharge function.

FIG. 13 is a longitudinal section of a ninth gas diffusion layer 2 that can be used in the fuel cell power generation cell of FIG.
The communication flow path 8 is formed so that the terminal end portion 9 exists inside the gas diffusion layer 2 and the tapered tube portions 6 communicate with each other. Thereby, as described above, the liquid water recovery / discharge function can be further improved.
On the other hand, the gas diffusion layer 2 shown in FIG. 13 can be made of a hydrophilic material (for example, a contact angle of 5 °) instead of the water repellent material. At this time, liquid water or the like is drawn into the pores of the gas diffusion layer 2, and liquid water or the like is unlikely to exist in the space of the tapered tube portion 6. Rather, the tapered tube portion 6 is easily used for gas flow. Since liquid water or the like is supplied to the electrolyte membrane 3 through a portion in contact with the electrolyte membrane 3, drying of the electrolyte membrane 3 can be suppressed.

FIG. 14 is a cross section of an eighth gas diffusion layer 2 that can be used in the fuel cell power generation cell of FIG. That is, it is an example of an aggregate (colony state) formed by a plurality of tapered tube portions 6.
The tapered tube portion 6 in the gas diffusion layer 2 has a large average diameter disposed at the center, and a tapered tube portion 6 having a smaller diameter as it goes away from the periphery.
In addition, as shown in FIG. 15, it is preferable that a tapered pipe portion 6 is communicated radially and through a tree root with a communication pipe 8 inside the gas diffusion layer 2. This structure makes it possible to move liquid water or the like in the in-plane direction by applying a mechanism for collecting liquid from a narrow space to a wide space. Thus, it is possible to move liquid water or the like to the intended position outside the gas diffusion layer 2 by the tapered tube portion 6.
Furthermore, as shown in FIG. 16, the tree-like colony structure of the tree can be arranged over the entire area of the gas diffusion layer 2. Further, these colony configurations can appropriately change the existence density of the tapered tube portion 6 in the in-plane direction of the gas diffusion layer 2. For example, it is possible to further improve the mobility of liquid water or the like by installing many in places where liquid water or the like is likely to be generated and not installing in places where liquid water or the like is not generated.

FIG. 17 shows a fuel cell power generation cell in which the gas diffusion layer 2 having the tapered tube portion 6 is installed only on the cathode side, and the opening of the tapered tube portion 6 is expanded so as to expand toward the cathode channel 12 side. .
In this case, liquid water or the like generated inside the gas diffusion layer 2 can be positively discharged from the gas diffusion layer 2 into the cathode gas channel 12 via the tapered tube portion 6. FIG. 17 is a vertical cross section including the tapered tube portion 6.

FIG. 18 shows a fuel cell power generation cell in which the gas diffusion layer 2 including the tapered tube portion 6 is installed only on the anode side, and the opening of the tapered tube portion 6 is disposed so as to reduce the diameter toward the anode channel 13 side. .
In this case, liquid water or the like generated inside the gas diffusion layer 2 can actively move to the electrolyte membrane 3 from the inside of the gas diffusion layer 2 through the tapered tube portion 6. FIG. 18 is a longitudinal section including the tapered tube portion 6.

FIG. 19 is a schematic cross-sectional view of a fuel cell power generation cell in which the gas diffusion layer 2 including the tapered tube portion 6 is installed on the cathode side and the anode side. The cathode-side gas diffusion layer 2 is installed so that the diameter of the opening of the tapered tube portion 6 increases toward the cathode channel 12 side. The gas diffusion layer 2 on the anode side is installed so that the opening of the tapered tube portion 6 is reduced in diameter toward the anode channel 13 side.
As a result, even when the liquid water is generated on both the cathode side and the anode side, the liquid water can be more reliably guided, and the tapered tube portion 6 is provided only on the gas diffusion layer 2 on one side. A synergistic effect can be obtained.

FIG. 20 is a diagram schematically showing an example of a vanishing type for forming a tapered tube portion of a gas diffusion layer and a method for manufacturing the same.
For example, if the vanishing type 14 using PTFE is used, the gas diffusion layer is subjected to water repellency treatment, and the intended network space of the tapered tube portion 6 can be formed.

In addition, as a method for manufacturing the disappearance mold 14, for example, the master mold 15 is first manufactured by a male mold using a durable metal or the like. Here, considering that the thickness of a typical gas diffusion layer is about 200 μm, the tapered tube portion 6 and the communication channel 8 have a size of the order of several tens of μm. Therefore, the master die 15 can be obtained by micromachining MEMS or ultrafine cutting.
Next, using this master mold 15 as a base, a female mold 16 for producing a disappearing mold is made of a flexible resin or the like. The disappearance mold 14 is obtained by pouring PTFE into the female mold 16 and solidifying it.

It is a schematic sectional drawing which shows an example of the cell structure of a fuel cell stack. It is a schematic sectional drawing which shows an example of a gas diffusion layer. It is a schematic sectional drawing which shows the mechanism in which the droplet in a taper-shaped pipe part moves. It is a schematic sectional drawing which shows an example of a gas diffusion layer. It is a schematic sectional drawing which shows an example of a gas diffusion layer. It is a schematic sectional drawing which shows an example of a gas diffusion layer. It is a schematic sectional drawing which shows an example of a gas diffusion layer. It is the schematic which shows an example of a mesh-like object. It is a schematic sectional drawing which shows an example of the gas diffusion layer obtained by laminating | stacking electroconductive micro bead. It is a schematic sectional drawing which shows an example of a gas diffusion layer. It is the schematic which shows the movement of the liquid between the taper-shaped pipe parts which connected. It is a schematic sectional drawing which shows an example of a gas diffusion layer. It is a schematic sectional drawing which shows an example of a gas diffusion layer. It is a schematic sectional drawing which shows an example of a gas diffusion layer. It is a schematic sectional drawing which shows an example of a gas diffusion layer. It is a schematic sectional drawing which shows an example of a gas diffusion layer. It is the schematic which shows an example of a fuel cell power generation cell. It is the schematic which shows an example of a fuel cell power generation cell. It is the schematic which shows an example of a fuel cell power generation cell. It is the schematic which shows an example of a vanishing type | mold and the various type | molds for producing this.

Explanation of symbols

1 Separator 1a Channel 1b Rib 2 Gas diffusion layer (GDL)
3 Solid Electrolyte Membrane 6 with Catalyst Layer Installed on Surface 6 Tapered Tube Part 7 Mesh Object 8 Communication Channel 9 Connecting Tapered Tube Part Droplet with a Small Radius in Tapered Pipe Part (High Pressure)
10 Droplet with large radius in tapered tube (relatively small pressure)
12 Cathode gas channel 13 Asode gas channel 14 Dissipation mold 15 by resin such as PTFE 15 Master mold 16 Female mold for producing disappearance mold

Claims (9)

In a fuel cell power generation cell comprising a gas diffusion layer,
The gas diffusion layer is a porous body that has been subjected to a water-repellent treatment, an oil-repellent treatment, or a hydrophilic treatment, and a tubular portion having a tapered longitudinal section is formed inside the porous body. Fuel cell power generation cell.   2. The fuel cell power generation cell according to claim 1, wherein a plurality of the tapered tube portions are formed, and the rate of change in the cross-section in the longitudinal direction is not uniform.   The tapered tube portion forms an aggregate, and as the tapered tube portion is separated from the tapered tube portion at the center of the aggregate, another tapered tube portion is provided so that the radius of the tapered tube portion becomes smaller. The fuel cell power generation cell according to claim 2.   The taper-shaped tube portion forms an aggregate, and as the taper-shaped tube portion is separated from the taper-shaped tube portion at the center of the aggregate, the other taper-shaped tube portions are provided so that the rate of change in the cross section decreases. The fuel cell power generation cell according to claim 2 or 3, characterized in that   The fuel according to any one of claims 1 to 4, wherein the gas diffusion layer has a plurality of tapered tube portions, and adjacent tapered tube portions communicate with each other through a flow path. Battery power generation cell.   6. The fuel cell power generation cell according to claim 5, wherein the flow path for communicating the tapered tube portion is tapered and has a terminal portion.   The gas diffusion layer is provided on the cathode electrode side, and the tapered tube portion communicates while expanding from the power generation surface side to the gas channel side. The fuel cell power generation cell described.   The gas diffusion layer is provided on the anode electrode side, and the tapered tube portion communicates while expanding from the gas channel side to the power generation surface side. The fuel cell power generation cell described.   The fuel cell power generation cell according to any one of claims 1 to 8, wherein the tapered tube portion of the gas diffusion layer is formed of a disappearing type. Fuel cell power generation cell.

Images