JP4635451B2 - Fuel cell and separator - Google Patents

Description

  The present invention relates to a fuel cell and a separator, and more particularly to a technique for efficiently discharging generated water.

  In a solid electrolyte membrane type fuel cell, there is a problem of a decrease in power generation efficiency due to moisture (hereinafter referred to as generated water) generated in an electrode in response to a power generation reaction. Therefore, various techniques for removing generated water have been proposed. For example, a technique is known in which a separator constituting a fuel cell is made porous, and generated water is sucked into a porous portion of the separator (see, for example, Patent Document 1).

Japanese National Patent Publication No. 11-508726

  However, the above-described conventional technology does not consider good contact between the porous separator and the diffusion layer in which the generated water is condensed. For this reason, there was a possibility that the generated water condensed in the diffusion layer could not be sufficiently absorbed by the separator.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to efficiently remove generated water in a diffusion layer in a fuel cell including a porous separator.

In order to solve the above problems, a first aspect of the present invention provides a fuel cell. A first aspect of the present invention provides a fuel cell. The fuel cell according to the first aspect of the present invention allows an electrolyte membrane having catalyst layers disposed on both sides thereof, a diffusion layer disposed on both sides of the electrolyte membrane with the catalyst layers sandwiched therebetween, and allows permeation of liquid. A dense portion and a porous portion that allows liquid permeation, and when assembled with the electrolyte membrane and the diffusion layer, a contact region that comes into contact with the diffusion layer, and no contact with the diffusion layer A separator having a non-contact region that forms a reaction gas flow channel with the diffusion layer in each of the porous portion and the dense portion, and the region of the contact region with respect to the non-contact region in the porous portion A separator having an area ratio larger than a region area ratio of the contact region to the non-contact region in the dense portion is provided.

According to the fuel cell of the first aspect of the present invention, the region in contact with the diffusion layer in the separator composed of the dense portion and the porous portion with respect to the region in which the reaction gas flow path is formed without being in contact with the diffusion layer. Since the area area ratio is made larger in the porous portion than in the dense portion, the produced water condensed in the diffusion layer can be efficiently absorbed by the porous portion of the separator.

In the fuel cell according to the first aspect of the present invention, the separator has a contact area increasing portion that increases a contact area between the porous portion and the diffusion layer in the contact region of the porous portion. preferable. In such a case, since it has a contact area increasing portion that increases the contact area in the contact region between the porous portion of the separator and the diffusion layer, the generated water condensed in the diffusion layer is more efficiently removed. Can be absorbed.

  In the fuel cell, the contact area increasing portion may be an uneven shape portion having an uneven shape on a contact surface between the porous portion and the diffusion layer. Moreover, the curved surface part which has a curved surface shape in the contact surface of the said porous part and the said diffusion layer may be sufficient. In such a case, since the contact surface of the porous portion with the diffusion layer has an uneven shape or a curved surface, the contact area with the diffusion layer increases, and the water condensed in the diffusion layer is efficiently removed from the separator. It can be absorbed in the porous part.

  In the fuel cell, the contact area increasing portion may be a high roughness surface portion having a high roughness surface on a contact surface between the porous portion and the diffusion layer. In such a case, since the surface roughness of the contact surface of the porous part with the diffusion layer is rough, the contact area with the diffusion layer is increased, and the generated water condensed in the diffusion layer is efficiently used. It can be well absorbed by the porous portion of the separator.

A second aspect of the present invention is a separator that constitutes a fuel cell by sandwiching an electrolyte membrane having catalyst layers disposed on both sides and a diffusion layer disposed on both sides of the electrolyte membrane with the catalyst layer sandwiched therebetween. I will provide a. When the separator according to the second aspect of the present invention is assembled with the electrolyte membrane and the diffusion layer, the separator is in contact with the diffusion layer and the diffusion layer without being in contact with the diffusion layer. A non-contact region that forms a reaction gas flow path, a dense portion that does not allow liquid permeation, and a porous portion that includes the contact region and the non-contact region and allows liquid permeation. And a porous portion having a region area ratio of the contact region with respect to the non-contact region larger than a region area ratio of the contact region with respect to the non-contact region in the dense portion.

If the fuel cell is configured using the separator according to the second aspect of the present invention, the same operational effects as those of the fuel cell according to the first aspect of the present invention can be obtained. The separator according to the second aspect of the present invention is realized in various aspects in the same manner as the fuel cell according to the first aspect of the present invention.

  Hereinafter, a fuel cell according to the present invention will be described based on examples with reference to the drawings.

First embodiment:
A schematic configuration of the fuel cell according to the first embodiment will be described with reference to FIGS. FIG. 1 is an explanatory diagram showing a schematic external configuration of the fuel cell according to the present embodiment. FIG. 2 is an explanatory view showing a schematic configuration of a facing surface (hereinafter referred to as an electrode facing surface) of the cathode separator constituting the fuel cell according to the present embodiment with the membrane-electrode assembly. FIG. 3 is an explanatory diagram showing a schematic configuration of a surface (hereinafter referred to as a cooling channel surface) on which a cooling channel of the cathode separator constituting the fuel cell according to the present embodiment is formed. FIG. 4 is an explanatory diagram showing a schematic configuration of the electrode facing surface of the anode separator constituting the fuel cell according to the present embodiment. FIG. 5 is an explanatory diagram showing a schematic configuration of a longitudinal section obtained by cutting a part of the fuel cell according to the present embodiment in the longitudinal direction (for example, along line 5-5 in FIG. 2).

  The fuel cell 10 according to the present embodiment includes a plurality of single cells 20, an end plate 30, and a tension plate 31. The plurality of single cells 20 are sandwiched between two end plates 30, and a tension plate 31 is coupled to each end plate 30 by bolts 32, thereby forming a stacked fuel cell 10.

  The single cell 20 includes a membrane-electrode assembly 21, a cathode separator 22, and an anode separator 23. A plurality of single cells 20 are stacked such that the cathode separator 22 and the anode separator 23 are in contact with each other.

  As shown in FIG. 5, the membrane-electrode assembly 21 includes an electrolyte membrane 211 made of an ion exchange membrane, and an electrode made of a catalyst layer disposed on one surface of the electrolyte membrane 211 (for example, an anode electrode, not shown). And an electrode (for example, a cathode electrode, not shown) made of a catalyst layer disposed on the other surface of the electrolyte membrane 211, and a diffusion layer 212 disposed on the separator facing surface of each catalyst layer. The membrane-electrode assembly 21 includes an electrolyte membrane 211 and a catalyst layer (electrode), and a diffusion layer 212 may be provided as a separate component. In either case, the electrolyte membrane 211, the catalyst layer, and the diffusion layer 212 are sandwiched between the separators 22 and 23.

  The cathode separator 22 is made of a conductive material such as carbon, metal, or conductive resin. Most of the cathode separator 22 is formed of a dense portion, but the lower central region in FIGS. 2 and 3 is formed of a porous portion 40. The porous part 40 can be formed of the same material as the dense part by using a porous metal such as carbon, sintered metal, or metal mesh formed in a porous shape. The porous portion 40 may be molded integrally with the dense portion, or may be joined or bonded to the dense portion after being separately molded.

  The cathode separator 22 includes an electrode facing surface 22a and a cooling flow path surface 22b. The cathode separator 22 includes an oxidizing gas supply unit 221a, an oxidizing gas discharge unit 221b, a fuel gas supply unit 222a, and a fuel gas discharge unit 222b. The oxidizing gas flow path forming part (225S, 225P) communicates with the oxidizing gas supply part 221a upstream and with the oxidizing gas discharge part 221b downstream. The oxidizing gas is introduced from the oxidizing gas supply unit 221a into the oxidizing gas channel formed between the oxidizing gas channel forming unit (225S, 225P) and the diffusion layer 212, and flows as shown in FIG. It is discharged from the oxidizing gas discharge unit 221b.

  The cathode separator 22 further includes a coolant supply part 223a, a coolant discharge part 223b, a coolant gas supply part 224a, and a coolant gas discharge part 224b. Through these, the coolant and the cooling gas are supplied to the fuel cell 10 and discharged from the fuel cell 10. As is clear from FIGS. 2 and 3, the cooling gas discharge unit 224b and the oxidizing gas supply unit 221a are realized by the same opening, and the opening serves both functions.

  The electrode facing surface 22a of the cathode separator 22 will be described with reference to FIG. A substantially center of the electrode facing surface 22a of the cathode separator 22 forms a region DA (hereinafter referred to as a diffusion layer facing region DA) facing the diffusion layer 212 disposed on the cathode electrode side of the membrane-electrode assembly 21 when assembled. . The diffusion layer facing area DA forms an oxidizing gas flow path between a region that contacts the diffusion layer 212 during assembly (hereinafter referred to as a contact region) and a diffusion layer 212 that does not contact the diffusion layer 212 during assembly. Region (hereinafter referred to as a non-contact region). In FIG. 2, the contact area is a hatched area 229S and a cross-hatched area 229P, and the non-contact area is an area where the oxidizing gas flow path forming portion (225S, 225P) is formed. is there. The cathode separator 22 functions to electrically connect the adjacent single cells 20 in the contact region (229S, 229P), and serves as a cathode electrode in the non-contact region (oxidation gas flow path forming portions 225S, 225P). It fulfills the function of supplying oxidizing gas.

  In addition to the above-described function, the porous portion 40 of the cathode separator 22 absorbs water (generated water) generated on the cathode side due to the electromotive reaction of the single cell 20 by capillarity and prevents flooding. Have For this reason, the porous part 40 is arrange | positioned in the lower area | region of the diffusion layer opposing area | region DA where generated water tends to stay. In particular, the contact region 229P in the porous portion 40 allows the generated water to pass directly from the diffusion layer 212 before the generated water enters the oxidizing gas flow channel from the diffusion layer 212 and stays and condenses to inhibit the power generation reaction. It can be sucked into the mass part 40.

  In this embodiment, the area area ratio of the contact region 229P in the porous portion 40 to the non-contact region (oxidation gas flow path formation portion 225P) is set to be the non-contact region (oxidation gas flow passage formation portion) of the contact region 229S in the dense portion. 225S) is set larger than the area ratio. Specifically, as shown in FIG. 5, the contact region and the non-contact region are formed by alternately arranging peaks and grooves in the cross-sectional view, but the contact region is formed in the porous portion 40. The ratio A2 / B2 between the width A2 of the peak portion and the width B2 of the groove portion forming the non-contact region is the ratio of the width A1 of the peak portion forming the contact region in the dense portion and the width B1 of the groove portion forming the non-contact region. It is set to be larger than A1 / B1. Here, the area of the area means not the surface area but the area determined only by the outer dimensions. For example, the area of the cross-hatched region 229P in FIG. 2 is represented by 2 × A2 × C, and the contact surface with the diffusion layer 212 in the region 229P may be a flat surface or have an uneven shape. It shall be the same value.

  The cooling flow path surface 22b of the cathode separator 22 will be described with reference to FIG. On the cooling channel surface 22 b of the cathode separator 22, a cooling liquid channel forming part 226 is formed in the dense part, and a cooling gas channel forming part 227 is formed in the porous part 40. As shown in FIG. 5, the cooling liquid flow path forming unit 226 and the cooling gas flow path forming part 227 include a cooling flow path surface 22 b of the cathode separator 22 and a cooling flow path surface of the anode separator 23 having similar flow path forming portions. 23b is combined to form the coolant channel 50 and the coolant gas channel 55, respectively.

  The coolant channel 50 communicates with the coolant supply unit 223a and the coolant discharge unit 223b, and cools the fuel cell 10 by liquid cooling. The cooling gas channel 55 communicates with the cooling gas supply unit 224a and the cooling gas discharge unit 224b, and cools the fuel cell 10 by air cooling. As the cooling liquid, for example, an antifreeze liquid (ethylene glycol or the like) that does not freeze even in a sub-freezing environment is used. As the cooling gas, for example, air that can be used as an oxidizing gas is used.

  The cooling gas passing through the cooling gas channel 55 is humidified by the generated water absorbed by the porous portion 40 from the diffusion layer 212 when passing through the porous portion 40. In other words, the dry cooling gas takes away the moisture (product water) contained in the porous part 40 by the vaporization phenomenon, so that the generated water absorbed in the porous part 40 is removed from the porous part 40. It is discharged into the cooling gas.

  The anode separator 23 is formed of a conductive material such as carbon, metal, or conductive resin, for example, in the same manner as the cathode separator 22. The anode separator 23 in the present embodiment is formed of only a dense part. The anode separator 23 includes a facing surface (electrode facing surface) 23a facing the membrane-electrode assembly 21 and a cooling flow path surface 23b in which a cooling flow path is formed.

  The anode separator 23 includes an oxidizing gas supply unit 231a, an oxidizing gas discharge unit 231b, a fuel gas supply unit 232a, and a fuel gas discharge unit 232b. The fuel gas flow path forming part 235 communicates with the fuel gas supply part 232a upstream and the fuel gas discharge part 232b downstream. The fuel gas is introduced from the fuel gas supply unit 232a into the fuel gas channel formed between the fuel gas channel forming unit 235 and the diffusion layer 212, and flows as shown in FIG. It is discharged from 232b.

  As with the cathode separator 22, the anode separator 23 includes a cooling liquid supply unit 233a, a cooling liquid discharge unit 233b, a cooling gas supply unit 234a, and a cooling gas discharge unit 234b. The cooling gas discharge part 234b and the oxidizing gas supply part 231a are realized by the same opening as in the cathode separator 22.

  The electrode facing surface 23a of the anode separator 23 will be described with reference to FIG. A substantially center of the electrode facing surface 23a of the anode separator 23 forms a region DA (hereinafter referred to as a diffusion layer facing region DA) facing the diffusion layer 212 disposed on the anode electrode side of the membrane-electrode assembly 21 when assembled. . The diffusion layer facing area DA is an area (contact area) that is in contact with the diffusion layer 212 during assembly, and an area that is not in contact with the diffusion layer 212 during assembly and forms a fuel gas flow path between the diffusion layer 212 (non-contact). Contact area). In FIG. 4, the contact region is a hatched region 239, and the non-contact region is a region where the fuel gas flow path forming part 235 is formed. The anode separator 23 functions to electrically connect the adjacent single cells 20 in the contact region 239, and in the non-contact region (fuel gas flow path forming portion 235), the anode separator 23 has fuel gas (this embodiment). In this case, it functions to supply hydrogen).

  The outer periphery of the cathode separator 22 and the anode separator 23, the periphery of each supply portion and the discharge portion are sealed as shown in FIGS. 2 to 4 in order to prevent leakage and mixing between each reaction gas and the cooling medium. The part 60 (sealing material) is arranged.

  Since the configuration of the cooling flow path surface 23b of the anode separator 23 is the same as that of the cooling flow path surface 22b of the cathode separator 22 except that the porous portion 40 is not provided, the description thereof is omitted.

  According to the fuel cell 10 according to the first embodiment configured as described above, the portion of the cathode separator 22 corresponding to the region where the generated water tends to stay (the lower region of the diffusion layer facing region DA) In the porous part 40 to be configured, the area ratio of the contact area 229P to the non-contact area (oxidation gas flow path forming part 225P) is set to the non-contact area of the contact area 229S in the dense part (oxidation gas flow path forming part 225S). Therefore, the generated water can be efficiently removed from the diffusion layer 212. That is, since the contact area between the porous portion 40 and the diffusion layer 212 can be increased, the generated water generated at the cathode electrode and condensed in the diffusion layer 212 is efficiently absorbed from the diffusion layer 212 to the porous portion 40. can do.

  Further, since the cooling gas channel 55 is formed on the cooling channel surface 22b side of the porous part 40 and the cooling gas flows, the generated water absorbed in the porous part 40 is discharged into the cooling gas. Can do. Thereby, the generated water condensed in the diffusion layer 212 can be continuously absorbed by the porous portion 40.

  Moreover, since the cooling gas discharge parts (224b, 234b) and the oxidizing gas supply parts (221a, 231a) are formed by the same opening, the humidified cooling gas can be used as the oxidizing gas. As a result, a humidifier for humidifying the oxidizing gas is unnecessary, or the humidifier can be downsized.

Second Embodiment With reference to FIGS. 6 and 7, a fuel cell according to a second embodiment of the present invention will be described. FIG. 6 is an explanatory diagram showing a schematic configuration in the vicinity of the porous portion 40 in a longitudinal section obtained by cutting a part of the fuel cell according to the present embodiment in the longitudinal direction. FIG. 7 is an explanatory view showing a schematic shape of a contact surface of the porous portion 40 of the cathode separator 22 used in the fuel cell according to this embodiment with the diffusion layer 212. FIG. 7 shows the porous portion 40 including a part of the contact region 229P corresponding to the portion indicated by AA in FIGS. Fig.7 (a) is a front view seen from the electrode opposing surface 22a side, FIG.7 (b), (c) is an end view (YY end surface and XX end surface) corresponding to Fig.7 (a). ).

  Since the schematic configuration of the fuel cell according to the second embodiment is the same as that of the fuel cell 10 according to the first embodiment shown in FIGS. 1 to 4, the description of the schematic configuration is omitted, and in the following description , The same code is used.

  The difference from the fuel cell according to the first embodiment is that the porous portion 40 of the cathode separator 22 of the fuel cell according to the second embodiment has a porous portion 40 and a diffusion layer 212 as shown in FIG. The contact region 229P has a shape (hereinafter referred to as a contact surface shape) 71 that increases the contact area with the diffusion layer 212 as a contact area increasing means. Specifically, as shown in FIG. 7, the porous portion 40 has a plurality of substantially triangular groove-like shapes in which the YY end surface is a saw blade shape on the contact surface with the diffusion layer 212 in the contact region 229P. 71. Here, the contact area with the diffusion layer 212 refers to a surface area that actually contacts the diffusion layer 212 during assembly. Therefore, for example, the contact area differs between the case where the contact surface with the diffusion layer 212 in the region 229P is a flat surface and the case where the contact surface has an uneven shape.

  The contact surface shape is such that when the diffusion layer 212 is pressed against the diffusion layer 212 during assembly, the diffusion layer 212 becomes a contact surface shape, or the contact surface shape bites into the diffusion layer 212. The detailed dimensions such as depth are determined so that the contact area with 40 is larger than that when the contact surface is a flat surface. The diffusion layer 212 may be made of carbon cloth, carbon paper, carbon felt or the like woven with carbon fiber yarns. There are various types, such as thickness and hardness (deformability). There are various. The contact surface shape is determined so that the area of the contact surface between the diffusion layer 212 and the porous portion 40 is as large as possible in consideration of the properties of the diffusion layer 212 used in the fuel cell 10 and the like. Below, some other aspects of contact surface shape are illustrated.

Other aspects of contact surface shape:
Other aspects of the contact surface shape will be described with reference to FIGS. 8-10 is explanatory drawing which shows the contact surface shape of the porous part 40 of the cathode separator 22 which concerns on another aspect, respectively.

  As shown in FIG. 8, the porous portion 40 may have a plurality of substantially triangular groove-like shapes 72 on the contact surface with the diffusion layer 212 so that the end face of the XX is a saw blade shape. good. Further, as shown in FIG. 9, the porous portion 40 has a shape 73 on the contact surface with the diffusion layer 212 so that both the YY end surface and the XX end surface have a saw blade shape. Also good. In such a case, the porous portion 40 has a substantially quadrangular pyramid shape on the contact surface with the diffusion layer 212.

  Hereinafter, only the shape of the YY end face will be illustrated with reference to FIG. 10, but the XX end face may have the exemplified shape as in the saw blade shape described above, or the YY end face. Further, the shape may be applied so that both the end face and the XX end face have the illustrated shape. FIG. 10A shows an example in which the YY end face is shaped like a semi-cylindrical shape 74, and FIG. 10B shows an example where a shape 75 obtained by inverting the semi-cylindrical shape shown in FIG. In these shapes, the porous portion 40 and the diffusion layer 212 are likely to be in point contact depending on the type (for example, hard) of the diffusion layer combined with the saw blade shape, whereas the diffusion layer 212 is relatively easy to touch. Shape. As an approximate shape, there is a roof shape 76 as shown in FIG.

  In addition, a corrugated shape 77 as shown in FIG. 10D is conceivable as an example of a shape in which the ease of attachment to the diffusion layer 212 is about the middle between the saw blade shape and the kamaboko shape. Further, as shown in FIG. 10E, the contact area may be increased by making the contact surface with the diffusion layer 212 a high roughness surface 78 having a rough surface roughness without giving a specific shape. .

  The fuel cell 10 according to the second embodiment configured as described above has the following effects in addition to the same effects as those of the fuel cell 10 according to the first embodiment.

  In the porous portion 40 of the cathode separator 22, the contact surface between the diffusion layer 212 and the porous portion 40 has a shape such as a saw blade shape as a contact area increasing means. The contact area increases. As a result, the generated water condensed in the diffusion layer 212 can be more efficiently absorbed from the diffusion layer 212 into the porous portion 40 and discharged into the cooling gas.

In the above embodiment, instead of the cathode separator 22 having the configuration of the electrode facing surface 22a described with reference to FIG. 2, a cathode separator having an electrode facing surface configured as shown in FIG. 11 is used. Also good. FIG. 11 is an explanatory diagram showing a schematic configuration of the electrode facing surface of the cathode separator of the fuel cell according to the first modification. The cathode separator used in this modification includes a plurality of protrusions in the diffusion layer facing area DA, and the oxidizing gas flow path is defined by the plurality of protrusions. That is, as shown in FIG. 11, the non-contact areas (oxidizing gas flow path forming portions 225S, 225P) are formed in a mesh shape, and the contact areas 229S, 229P (plural protrusions) are formed in a substantially square shape. The lengths A2 and C2 of the substantially square sides forming the contact region 229S in the porous portion 40 are set larger than the lengths A1 and C1 of the substantially square sides forming the contact region 229P in the dense portion. Yes. In the example shown in FIG. 11, the plurality of protrusions are substantially square, but are not limited to this, and may have other shapes.

  Moreover, you may use the cathode separator provided with the electrode opposing surface comprised as shown in FIG. FIG. 12 is an explanatory diagram showing a schematic configuration of the electrode facing surface of the cathode separator of the fuel cell according to the second modification. In the above embodiment, as described in FIG. 2, the oxidizing gas flow path forming portion 225 is partitioned so that the oxidizing gas flow path is formed in the left-right direction of the drawing in the diffusion layer facing area DA. In the cathode separator 22 used in this modification, the oxidizing gas flow path forming part 225 is partitioned so that the oxidizing gas flow path is formed in the vertical direction of the drawing in the diffusion layer facing area DA. The flow path width B2 on the downstream side (portion corresponding to the porous part 40) of the formed oxidizing gas flow path is set to be narrower than the flow path width B1 on the upstream side (part corresponding to the dense part). Yes. As a result, the width of the contact region (229S and 229P) between the oxidizing gas flow paths is wider in the porous portion 40 than in the dense portion (A1 <A2). The cooling separator cooling channel surface and anode separator according to the modification correspond to the configuration of the electrode facing surface of the cathode separator, and the configuration according to the embodiment can be used, and there is no characteristic part. Omitted.

  The two types of cathode separators configured as described above are similar to the cathode separator 22 of the fuel cell 10 according to the first and second embodiments described above, and the contact region (229P) in the porous portion 40 is not covered. The area ratio with respect to the contact area (oxidizing gas flow path forming part 225P) is larger than the area ratio of the contact area (229S) in the dense part with respect to the non-contact area (oxidizing gas flow path forming part 225S). Therefore, also in the fuel cell 10 according to these modified examples, the generated water condensed in the diffusion layer 212 is efficiently absorbed from the diffusion layer 212 into the porous portion 40 and discharged into the cooling gas, similarly to the embodiment. be able to.

  In the above embodiment, the cathode separator 22 includes the porous portion 40, but the anode separator 23 may include the porous portion 40. In such a case, various means for increasing the contact area between the diffusion layer 212 and the porous portion 40 described for the cathode separator 22 in the embodiment are set on the electrode facing surface side of the anode separator 23. Since moisture may appear on the anode side due to reverse osmosis or the like, in such a case, the appeared moisture can be efficiently absorbed into the porous portion 40 and removed.

  In the above embodiment, the supply mode of the oxidizing gas, the fuel gas, the cooling liquid, and the cooling gas is not described in detail. However, the gas can be supplied by an external gas pump if it is a gas, and can be supplied by an external liquid pump if it is a liquid. . As for the fuel gas, when high-pressure fuel gas is used, the supply amount may be adjusted by pressure control without using a pump.

As mentioned above, although the Example and modification of this invention were demonstrated, this invention is not limited to these Example and modification at all, and implementation in a various aspect is possible within the range which does not deviate from the summary. It is.
Another aspect 1 of the present invention provides a fuel cell. A fuel cell according to another aspect of the present invention includes an electrolyte membrane in which catalyst layers are disposed on both surfaces, a diffusion layer disposed on both surfaces of the electrolyte membrane with the catalyst layers interposed therebetween, the electrolyte membrane, and the electrolyte membrane When assembled with the diffusion layer, at least a part of the contact region that comes into contact with the diffusion layer is made of a porous material that allows permeation of liquid, and the contact area increasing portion that increases the contact area with the diffusion layer It is characterized by providing with the separator which has.
According to the fuel cell of another aspect 1 of the present invention, the contact area with the diffusion layer in the porous portion of the separator has the contact area increasing portion that increases the contact area with the diffusion layer. The condensed product water can be efficiently absorbed by the porous portion of the separator.
In the fuel cell, the contact area increasing portion may be an uneven shape portion having an uneven shape on a contact surface between the porous portion and the diffusion layer. Moreover, the curved surface part which has a curved surface shape in the contact surface of the said porous part and the said diffusion layer may be sufficient. In such a case, since the contact surface of the porous portion with the diffusion layer has an uneven shape or a curved surface, the contact area with the diffusion layer increases, and the water condensed in the diffusion layer is efficiently removed from the separator. It can be absorbed in the porous part.
In the fuel cell, the contact area increasing portion may be a high roughness surface portion having a high roughness surface on a contact surface between the porous portion and the diffusion layer. In such a case, since the surface roughness of the contact surface of the porous part with the diffusion layer is rough, the contact area with the diffusion layer is increased, and the generated water condensed in the diffusion layer is efficiently used. It can be well absorbed by the porous portion of the separator.
Another aspect 2 of the present invention is a separator that constitutes a fuel cell by sandwiching an electrolyte membrane having catalyst layers disposed on both sides and a diffusion layer disposed on both sides of the electrolyte membrane with the catalyst layer sandwiched therebetween. I will provide a. The separator according to another aspect 2 of the present invention is a porous member that constitutes at least a part of a contact region that comes into contact with the diffusion layer when assembled with the electrolyte membrane and the diffusion layer, and allows liquid to pass therethrough. And a contact area increasing portion that is provided in the contact region composed of the porous portion and increases the contact area between the porous portion and the diffusion layer.
If a fuel cell is comprised using the separator which concerns on the other aspect 2 of this invention, the effect similar to the fuel cell which concerns on the other aspect 1 of this invention can be acquired. Further, the separator according to the other aspect 2 of the present invention is realized in various aspects in the same manner as the fuel cell according to the other aspect 1 of the present invention.

It is explanatory drawing which shows schematic structure of the external appearance of the fuel cell 10 which concerns on a 1st Example. It is explanatory drawing which shows schematic structure of the opposing surface (electrode opposing surface) 22a with the membrane-electrode assembly 21 of the cathode separator 22 which comprises the fuel cell 10 which concerns on a 1st Example. It is explanatory drawing which shows schematic structure of the surface (cooling flow path surface) 22b in which the cooling flow path of the cathode separator 22 which comprises the fuel cell 10 which concerns on a 1st Example is formed. It is explanatory drawing which shows schematic structure of the electrode opposing surface of the anode separator 23 which comprises the fuel cell 10 of a 1st Example. FIG. 5 is an explanatory diagram showing a schematic configuration of a longitudinal section obtained by cutting a part of the fuel cell 10 according to the first embodiment in the longitudinal direction (for example, along line 5-5 in FIG. 2). It is explanatory drawing which shows schematic structure of the porous part 40 vicinity in the longitudinal cross-section which cut | disconnected a part of fuel cell which concerns on a 2nd Example in the vertical direction. It is explanatory drawing which shows the shape (contact surface shape) of the contact surface with the diffused layer 212 of the porous part 40 of the cathode separator 22 used for the fuel cell 10 which concerns on a 2nd Example. It is the 1st explanatory view showing the contact surface shape of porous part 40 of cathode separator 22 concerning other modes. It is the 2nd explanatory view showing the contact face shape of porous part 40 of cathode separator 22 concerning other modes. It is a 3rd explanatory view which shows the contact surface shape of the porous part 40 of the cathode separator 22 which concerns on another aspect. It is explanatory drawing which shows schematic structure of the electrode opposing surface of the cathode separator of the fuel cell which concerns on a 1st modification. It is explanatory drawing which shows schematic structure of the electrode opposing surface of the cathode separator of the fuel cell which concerns on a 2nd modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell 20 ... Single cell 21 ... Membrane-electrode assembly 211 ... Electrolyte membrane 212 ... Diffusion layer 22 ... Cathode separator 22a ... Electrode facing surface 22b ... Cooling flow path surface 221a ... Oxidizing gas supply part 221b ... Oxidizing gas discharge part 222a ... Fuel gas supply part 222b ... Fuel gas discharge part 223a ... Coolant supply part 223b ... Coolant discharge part 224a ... Coolant gas supply part 224b ... Coolant gas discharge part 225S ... Oxidized gas flow path forming part (non-contact region) in the dense part )
225P: Oxidizing gas flow path forming portion in the porous portion (non-contact region)
226 ... Cooling liquid flow path forming part 227 ... Cooling gas flow path forming part 229S ... Contact area in dense part 229P ... Contact area in porous part 23 ... Anode separator 23a ... Electrode facing surface 23b ... Cooling flow path surface 231a ... Oxidizing gas Supply portion 231b ... Oxidizing gas discharge portion 232a ... Fuel gas supply portion 232b ... Fuel gas discharge portion 233a ... Coolant supply portion 233b ... Coolant discharge portion 234a ... Cooling gas supply portion 234b ... Cooling gas discharge portion 235 ... Fuel gas flow path Forming part (non-contact area)
239 ... Contact area 30 ... End plate 31 ... Tension plate 40 ... Porous part 50 ... Coolant flow channel 55 ... Cooling gas channel 60 ... Seal part (seal material)
71-78 ... contact surface shape DA ... diffusion layer facing region

Claims (6)

A fuel cell,
An electrolyte membrane having catalyst layers on both sides;
A diffusion layer disposed on both sides of the electrolyte membrane with the catalyst layer interposed therebetween;
A contact region that has a dense part that does not allow liquid permeation and a porous part that allows liquid permeation, and is in contact with the diffusion layer when assembled with the electrolyte membrane and the diffusion layer; and the diffusion layer Non-contact regions that do not contact with the diffusion layer and that form a reaction gas flow path between the porous portion and the dense portion, respectively, with respect to the non-contact region in the porous portion A fuel cell comprising: a separator having a region area ratio of the contact region larger than a region area ratio of the contact region with respect to the non-contact region in the dense portion. The fuel cell according to claim 1 , wherein
The separator is
The fuel cell which has the contact area increase part which increases the contact area of the said porous part and the said diffusion layer in the said contact area in the said porous part. The fuel cell according to claim 2 , wherein
The contact area increasing portion is a fuel cell having a concavo-convex shape having a concavo-convex shape on a contact surface between the porous portion and the diffusion layer. The fuel cell according to claim 2 , wherein
The contact area increasing portion is a fuel cell having a curved shape having a curved shape on a contact surface between the porous portion and the diffusion layer. The fuel cell according to claim 2 , wherein
The contact area increasing portion is a fuel cell that is a high roughness surface portion having a surface having a high roughness on a contact surface between the porous portion and the diffusion layer. A separator that constitutes a fuel cell by sandwiching an electrolyte membrane in which a catalyst layer is disposed on both sides and a diffusion layer that is disposed on both sides of the electrolyte membrane with the catalyst layer interposed therebetween,
A contact region that contacts the diffusion layer when assembled with the electrolyte membrane and the diffusion layer, and a non-contact region that does not contact the diffusion layer and forms a reaction gas channel between the diffusion layer and the contact region. A dense portion that does not allow liquid to pass through;
A porous portion having the contact region and the non-contact region and allowing permeation of liquid, wherein the area area ratio of the contact region to the non-contact region is the non-contact region in the dense portion A separator provided with a porous part larger than the area ratio of the contact area.

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