JP5364990B2 - Fuel cell - Google Patents

Description

  The present invention relates to a technique for constituting a fuel cell including a protective film for protecting an electrolyte membrane.

  2. Description of the Related Art Conventionally, a fuel cell having a so-called stack structure in which a membrane electrode assembly (MEA) and a separator are stacked and fastened in a stacking direction has been developed (see Patent Documents 1 and 2 below).

JP 2006-216424 A JP 2006-210027 A

  MEAs used for fuel cells include an electrolyte membrane, a catalyst layer disposed on the electrolyte membrane, a porous gas diffusion layer disposed on the catalyst layer, and a protective film for protecting the electrolyte membrane. There is something to prepare.

  FIG. 5 is an explanatory view showing an example of a cross section of a conventional MEA equipped with a protective film. The MEA 500 includes an electrolyte membrane 510, a catalyst layer 511, a gas diffusion layer 520, and a protective film 540. Note that a gasket 550 is disposed so as to surround the edge of the MEA 500. The catalyst layer 511 is disposed at the center of each surface (anode surface and cathode surface) of the electrolyte membrane 510. The protective film 540 is a film for protecting the electrolyte membrane 510 having a small thickness. The protective film 540 is disposed so as to cover the end portion of the electrolyte membrane 510 where the catalyst layer 511 is not disposed. The gas diffusion layer 520 is configured by, for example, pressing a porous body such as carbon paper on the gas diffusion layer 520.

  Here, the protective film 540 is disposed so as to form an overlapping portion 535 that overlaps with the catalyst layer 511. This is due to a manufacturing margin when the protective film 540 is disposed, and a reason that the electrolyte membrane can be protected even when the electrolyte membrane 510 extends in the horizontal direction when the fuel cell is operated. In the overlapping portion 535, the catalyst layer 511, the electrolyte membrane 510, and the protective film 540 are laminated. Therefore, when the porous body is pressure-bonded onto the gas diffusion layer 520, a convex portion 525 that protrudes in the stacking direction from other portions in the gas diffusion layer 520 is formed.

  When a separator (not shown) is laminated on such an MEA 500 and a fastening load is applied, a large load is applied to the protruding convex portion 525, and the other portions are not sufficiently loaded. Therefore, if a sufficient load is applied to a portion other than the convex portion 525, there is a problem that a very large load (fastening force) is required for the entire fuel cell. In addition, when the MEA 500 and the separator are fastened with a large force, a very large load is applied to the protruding portion 525 protruding from other portions, and the MEA 500 may be damaged at the protruding portion 525. Note that the above problem may occur even when the gas diffusion layer is not configured as a part of the MEA and is laminated on the MEA as another member different from the MEA.

  The present invention is a fuel cell including a protective sheet for protecting an electrolyte membrane, and can suppress an extremely large load for fastening each member constituting the fuel cell in the stacking direction. The purpose is to provide technology.

  In order to solve at least a part of the aforementioned problems, a fuel cell of the present invention includes an electrolyte membrane, a catalyst layer laminated on the electrolyte membrane, and a side opposite to the electrolyte membrane as viewed from the catalyst layer. The gas diffusion layer disposed, a region of the electrolyte membrane in which the catalyst layer is not laminated, and a protective film for the electrolyte membrane having an overlapping portion overlapping the catalyst layer, and facing the gas diffusion layer And at least one of the separator and the gas diffusion layer in a corresponding region corresponding to the overlapping portion in a stacking direction compared to other regions excluding the corresponding region. The gist is that the thickness is reduced.

  In the fuel cell according to the present invention, at least one of the separator and the gas diffusion layer has a smaller thickness in the stacking direction in the region corresponding to the overlapping portion than in the other regions. And the gas diffusion layer can be brought into contact with each other in a relatively wide area, and the fastening load can be prevented from becoming very large. Further, since the separator and the gas diffusion layer can be brought into contact with each other in a relatively wide range, it is possible to suppress the concentration of a very large force on the corresponding region in the gas diffusion layer. Damage to the diffusion layer, the electrolyte membrane, and the like can be suppressed.

  In the fuel cell, the electrolyte membrane, the catalyst layer, the protective film, and the gas diffusion layer may be configured as a membrane electrode assembly.

With such a configuration, when the fuel cell is configured, the membrane electrode assembly and the separator can be brought into contact with each other over a relatively wide range. Moreover, it can suppress that a membrane electrode assembly is damaged in an overlap part.
The fuel cell of the present invention includes an electrolyte membrane, a catalyst layer laminated on the electrolyte membrane, a gas diffusion layer disposed on the opposite side of the electrolyte membrane as viewed from the catalyst layer, and the electrolyte membrane Covering the region where the catalyst layer is not laminated, and having a protective film for the electrolyte membrane having an overlapping portion overlapping the catalyst layer, and a separator disposed to face the gas diffusion layer, At least one of the separator and the gas diffusion layer is configured so that the thickness in the stacking direction is smaller in the corresponding region corresponding to the overlapping portion than in other regions excluding the corresponding region, The electrolyte membrane, the catalyst layer, the protective film, and the gas diffusion layer are configured as a membrane electrode assembly, and the protective film is formed by laminating the catalyst layer and the electrolyte membrane. In regions where there, Orazu in contact with the electrolyte membrane, the separator is in the corresponding region is configured so that the thickness in the stacking direction is smaller than the other areas except for the corresponding region, the corresponding region May be constituted by a concave curved surface.

Hereinafter, the best mode for carrying out the present invention will be described in the following order based on examples.
A. First embodiment:
B. Second embodiment:
C. Variations:

A. First embodiment:
FIG. 1 is an exploded perspective view of a fuel cell as an embodiment of the present invention. The fuel cell 20 has a configuration in which seal-integrated MEAs 21 and separators 25 are alternately stacked. In the fuel cell 20, a plurality of seal-integrated MEAs 21 and separators 25 are stacked in the stacking direction (vertical direction). In FIG. 1, for convenience of illustration, one MEA 21 and one separator 25 are shown. doing.

  The separator 25 includes an anode facing plate 22, an intermediate plate 23, and a cathode facing plate 24. The anode facing plate 22 is disposed to face the anode surface of the seal-integrated MEA 21. Further, the cathode facing plate 24 is disposed so as to face the cathode surface of an adjacent seal-integrated MEA (not shown) in the lower part of the drawing. The intermediate plate 23 is sandwiched between the anode facing plate 22 and the cathode facing plate 24.

  The anode facing plate 22 includes a fuel gas supply manifold forming portion 221a. The anode facing plate 22 includes a fuel gas discharge manifold formation portion 221b, an oxidant gas supply manifold formation portion 222a, an oxidant gas discharge manifold formation portion 222b, a cooling medium supply manifold formation portion 223a, and a cooling medium discharge manifold. And a forming portion 223b. Each of these manifold forming portions 221a, 221b, 222a, 222b, 223a, and 223b is formed as a through portion that penetrates the anode facing plate 22 in the thickness direction. Further, the anode facing plate 22 includes a plurality of fuel gas supply holes 225 and a plurality of fuel gas discharge holes 226 in a region facing the MEA 50 in the seal-integrated MEA 21. The fuel gas supply hole 225 and the fuel gas discharge hole 226 are formed as penetrating portions that penetrate the anode facing plate 22 in the thickness direction.

  The cathode facing plate 24 includes a fuel gas supply manifold forming portion 241 a at the same position as the anode facing plate 22. The cathode facing plate 24 includes a fuel gas discharge manifold forming portion 241b, an oxidant gas supply manifold forming portion 242a, an oxidant gas discharge manifold forming portion 242b, a cooling medium supply forming portion manifold 243a, and a cooling medium discharge manifold. And a forming portion 243b. Each of these manifold forming portions 241a, 241b, 242a, 242b, 243a, 243b is formed as a through portion that penetrates the cathode facing plate 24 in the thickness direction. Further, the cathode facing plate 24 includes a plurality of oxidant gas supply holes 245 and a plurality of oxidant gas discharge holes 246. The oxidant gas supply hole 245 and the plurality of oxidant gas discharge holes 246 are formed as through portions that penetrate the cathode facing plate 24 in the thickness direction.

  The intermediate plate 23 includes a fuel gas supply manifold forming portion 231 a at the same position as the anode facing plate 22 and the cathode facing plate 24. Similarly, the intermediate plate 23 includes a fuel gas discharge manifold forming portion 231b, an oxidant gas supply manifold forming portion 232a, and an oxidant gas discharge manifold forming portion 232b. Each of these manifold forming portions 231a, 231b, 232a, 232b is formed as a through portion that penetrates the intermediate plate 23 in the thickness direction. Further, the intermediate plate 23 includes a fuel gas supply flow path forming part 235, a fuel gas discharge flow path forming part 236, an oxidant gas supply flow path forming part 237, and an oxidant gas discharge flow path forming part 238. ing. The fuel gas supply flow path forming part 235 is composed of a plurality of long holes, one end of each long hole communicating with the fuel gas supply manifold forming part 231a, and the other end of the fuel gas formed on the anode facing plate 22 It communicates with the supply hole 225. The other flow path forming portions 236 to 238 are configured in the same manner. Further, the intermediate plate 23 includes a plurality of elongated cooling medium flow path forming portions 239 that vertically cut through the intermediate plate. The flow path forming portions 235 to 239 in the intermediate plate 23 described above are formed as through portions that penetrate the intermediate plate 23 in the thickness direction.

  Each of the plates 22, 23, and 24 described above can be manufactured by forming the above-described through portions in a thin metal plate such as a titanium alloy or stainless steel (SUS).

  The seal-integrated MEA 21 includes an MEA 50 and a gasket 51 that surrounds the MEA 50. The gasket 51 includes a fuel gas supply manifold forming portion 211a at the same position as the anode facing plate 22 and the cathode facing plate 24 described above. Similarly, the gasket 51 includes a fuel gas discharge manifold formation portion 211b, an oxidant gas supply manifold formation portion 212a, an oxidant gas discharge manifold formation portion 212b, a cooling medium supply manifold formation portion 213a, and a cooling medium discharge manifold formation. Part 213b. Each of these manifold forming portions 211a, 211b, 212a, 212b, 213a, and 213b is formed as a through portion that penetrates the gasket 51 in the thickness direction. The gasket 51 can be formed of a resin material such as silicon rubber or butyl rubber, for example.

  On the cathode surface (front side) of the MEA 50, a convex portion 71c is formed along the edge at a position close to the edge. The convex portion 71c slightly protrudes upward from other portions on the cathode surface of the MEA 50. Similarly, a convex portion 71 a is also formed on the anode surface (back side) of the MEA 50. The convex portion 71a slightly protrudes downward from the other portions on the anode surface of the MEA 50, similarly to the convex portion 71c. In addition, these two convex parts 71c and 71a are formed so that it may become the same position seeing from the direction along the lamination direction.

  On the surface (front side) of the anode facing plate 22 facing the seal-integrated MEA 21, a recess 74 a is formed at a position corresponding to the convex portion 71 a of the seal-integrated MEA 21. The recess 74a is slightly smaller in thickness than the other part of the surface of the anode facing plate 22 facing the seal-integrated MEA 21. Note that no recess is formed on the surface (back side) of the anode facing plate 22 facing the intermediate plate 23.

  Similarly, a recess 74 c is formed on the back side of the cathode facing plate 24, that is, on the surface facing the seal-integrated MEA (not shown) adjacent below the cathode facing plate 24. Similar to the recess 74a, the recess 74c is slightly smaller in thickness than the other portions. And this recessed part 74c is formed in the position corresponding to the convex part 71c (illustration omitted) formed in the cathode surface which the seal integrated MEA which is not shown in figure has. In the present embodiment, the above-described recesses 74a and 74c correspond to corresponding regions in the claims.

  FIG. 2 is an explanatory view showing a cross section AA shown in FIG. In the seal-integrated MEA 21, the MEA 50 is configured as a so-called MEGA (Membrane-Electrode-Gas diffusion layer Assembly) including a gas diffusion layer. Specifically, the MEA 50 includes an electrolyte membrane 21b, an anode side gas diffusion layer 21a, and a cathode side gas diffusion layer 21c. The anode side gas diffusion layer 21 a is disposed to face the lower separator 25, and the cathode side gas diffusion layer 21 c is disposed to face the upper separator 25. As the electrolyte membrane 21b, for example, Nafion (registered trademark), Flemion (registered trademark), Aciplex (registered trademark) or the like, which is a fluororesin-based ion exchange membrane, can be used. Moreover, as the two diffusion layers 21a and 21c, for example, carbon paper or carbon cloth can be used.

  A fuel gas supply manifold 31a is formed by the fuel gas supply manifold forming portion 211a included in the seal-integrated MEA 21 and the fuel gas supply manifold forming portions 221a, 231a, and 241a included in the separator 25. Similarly, an oxidant gas supply manifold 31b provided in the seal-integrated MEA 21 and an oxidant gas supply manifold formation part 222a, 232a, 242a provided in the separator 25 form an oxidant gas supply manifold 31b.

  Further, a space (hereinafter referred to as “fuel gas supply flow path”) 255 surrounded by the fuel gas supply flow path forming portion 235 that is a through portion in the intermediate plate 23, the anode facing plate 22, and the cathode facing plate 24. Is formed. One end of the fuel gas supply path 255 communicates with the fuel gas supply hole 225, and the other end communicates with the fuel gas supply manifold 31a.

  Similarly, a space (hereinafter referred to as “oxidant gas supply flow path”) 257 surrounded by the oxidant gas supply flow path forming portion 237, the anode facing plate 22 and the cathode facing plate 24 is formed. . One end of the oxidant gas supply channel 257 communicates with the oxidant gas supply hole 245, and the other end communicates with the oxidant gas supply manifold 31b.

  Part of the fuel gas (for example, hydrogen gas) supplied through the fuel gas supply manifold 31 a flows into the fuel gas supply path 255 in the intermediate plate 23 of the lower separator 25 and passes through the fuel gas supply hole 225. To the anode-side gas diffusion layer 21a of the seal-integrated MEA 21. Then, the fuel gas is diffused in the anode side gas diffusion layer 21a and used for an electrochemical reaction in an anode electrode (not shown).

  On the other hand, a part of the oxidant gas (for example, air) supplied through the oxidant gas supply manifold 31b flows into the fuel gas supply channel 257 in the intermediate plate 23 of the upper separator 25 to supply the oxidant gas. The gas is supplied to the cathode-side gas diffusion layer 21c of the seal-integrated MEA 21 through the hole 245. Then, the oxidant gas is diffused in the cathode side gas diffusion layer 21c and used for the electrochemical reaction in the cathode electrode (not shown).

  The above is the operation when the fuel gas and the oxidant gas are supplied to the seal-integrated MEA 21, but the operation when the fuel gas and the oxidant gas are discharged from the seal-integrated MEA 21 is the same. For example, the fuel gas discharge operation is as follows. The fuel gas remaining without being used in the electrochemical reaction in the seal-integrated MEA 21 is a fuel gas discharge hole 226 (FIG. 1) provided in the seal-integrated MEA 21 and a fuel gas discharge communicating with the fuel gas discharge hole 226. It is discharged to the fuel gas discharge manifold through the flow path forming part 236. Here, the fuel gas discharge manifold is formed by a fuel gas discharge manifold forming portion 211b included in the seal-integrated MEA 21 and fuel gas discharge manifold forming portions 221b, 231b, and 241b included in the separator 25.

  FIG. 3 is an explanatory diagram showing a detailed configuration of the region X shown in FIG. The seal-integrated MEA 21 includes an MEA 50 and a gasket 21y disposed on an edge portion of the MEA 50. The MEA 50 includes an anode side catalyst layer 60a, a cathode side catalyst layer 60c, an anode side protective film fa, a cathode side, in addition to the electrolyte membrane 21b, the anode side gas diffusion layer 21a, and the cathode side gas diffusion layer 21c described above. A protective film fc. The anode side catalyst layer 60a is formed on the anode surface (lower side surface) of the electrolyte membrane 21b. Similarly, the cathode side catalyst layer 60c is formed on the cathode surface (upper side surface) of the electrolyte membrane 21b. As these catalyst layers 60a and 60b, for example, platinum-supporting carbon or the like can be used.

  The anode-side protective film fa is disposed so as to cover the electrolyte membrane 21b on the anode surface of a region 90 in which the anode-side catalyst layer 60a of the electrolyte membrane 21b is not formed (hereinafter referred to as “catalyst layer non-formed region”). ing. Similarly, the cathode-side protective film fc is disposed so as to cover the electrolyte membrane 21b on the cathode surface of the catalyst layer non-formation region 90. These two protective films fa and fb are for increasing the strength in the catalyst layer non-formed region 90 where the catalyst layers 60a and 60c are not formed and the electrolyte membrane 21b is exposed. As the two protective films fa and fb, for example, a PET (polyethylene terephthalate) film, a PEN (polyethylene naphthalate) film, a PI (polyimide) film, or the like can be used.

  Here, the anode side protective film fa covers the anode surface of the catalyst layer non-formation region 90, and a part thereof also covers the anode side catalyst layer 60a. This makes it possible to protect the non-catalyst layer formation region 90 even when the anode side protective film fa is disposed, or when the electrolyte membrane 21b extends in the horizontal direction when the fuel cell 20 is in operation. Because. Similarly, the cathode-side protective film fc covers the cathode surface side of the catalyst layer non-formation region 90, and a part thereof also covers the cathode-side catalyst layer 60c. Therefore, in the MEA 50, a portion (hereinafter referred to as “overlap portion”) 80 where the electrolyte membrane 21b, the two catalyst layers 60a and 60b, and the two protective films fa and fc are overlapped is formed. The overlapping portion 80 has a larger thickness in the stacking direction than other portions. Therefore, in the gas diffusion layers 21a and 21c, the portion corresponding to the overlapping portion 80 is formed so as to be higher than the other portions. Specifically, on the anode side, a convex portion 71a (see also FIG. 1) is formed in a portion corresponding to the overlapping portion 80. On the cathode side, a convex portion 71c (see also FIG. 1) is formed in a portion corresponding to the overlapping portion 80. In addition, the length which these two convex parts 71a and 71c protruded in the lamination direction compared with the other part will be about several tens of micrometers, for example.

  Here, in the anode facing plate 22 of the lower separator 25, a recess 74a is formed at a position corresponding to the above-described protrusion 71a. The recess 74a is formed to have a thickness slightly smaller than that of the other portions. The recess 74a can be formed by, for example, cutting a corresponding portion in a metal thin plate. In the example of FIG. 3, in a state where the seal-integrated MEA 21 and the lower separator 25 are stacked, the convex portions 71 a and the concave portions 74 a are in contact with each other without gaps with the same shape on the surface. At the same time, other portions of the anode-side gas diffusion layer 21a excluding the convex portion 71a and other portions of the anode facing plate 22 excluding the concave portion 74a are in contact with each other. Similarly, in the cathode facing plate 24 of the upper separator 25, a recess 74c is formed at a position corresponding to the above-described protrusion 71c. The convex portion 71c and the concave portion 74c are in contact with each other without a gap, and the other portion excluding the convex portion 71c in the cathode-side gas diffusion layer 21c and the other portion other than the concave portion 74c in the cathode facing plate 24 are: They are in contact with each other.

  As described above, in the fuel cell 20, the convex portion 71a is generated in the anode-side gas diffusion layer 21a due to the overlapping portion 80. However, since the concave portion 74a is provided in the anode facing plate 22, the anode facing plate 22 and the anode side gas diffusion layer 21a are in contact with each other over the entire surface. Further, the cathode side has almost the same configuration as the anode side, and the cathode facing plate 24 and the cathode side gas diffusion layer 21c are in contact with each other over the entire surface. Accordingly, when the seal-integrated MEA 21 and the separator 25 are stacked and fastened, a load can be applied to the entire surface, so that the load for fastening can be prevented from becoming very large. Further, in the seal-integrated MEA 21, it is possible to avoid the fastening load from concentrating on the convex portions 71 a and 71 c, so that the MEA 50 can be prevented from being damaged at the overlapping portion 80.

B. Second embodiment:
FIG. 4 is an explanatory view showing details of a cross section of the fuel cell in the second embodiment. In FIG. 4, a region (region X) at the same position as that in FIG. 3 is shown. The fuel cell in the second embodiment is different from the fuel cell 20 (FIGS. 1 to 3) in the following two points, and other configurations are the same as those in the first embodiment. That is, the point that the portion corresponding to the overlapping portion 80 in the gas diffusion layer does not protrude as compared with the other portions, and the point that the concave portion is not formed in the portion corresponding to the overlapping portion 80 in the separator 25a. This is the difference between this fuel cell and the fuel cell 20 (first embodiment).

  In the anode side gas diffusion layer 21d of the MEA 50a of the second embodiment, a portion 71d corresponding to the overlapping portion 80 (hereinafter referred to as “overlap corresponding portion”) 71d is slightly thinner than the other portions. It is configured. Specifically, the thickness of the overlap corresponding part 71d is h2, and the thickness h1 of the other part is larger than the thickness h2. By providing the thickness difference in this manner, the height of the upper surface of the overlap corresponding portion 71d (the length in the stacking direction with respect to the position of the electrolyte membrane 21b) is substantially the same as the height of the upper surface of other portions. It has become.

  The anode-side gas diffusion layer 21d having such a configuration can be formed as follows, for example. That is, in the manufacturing process of the MEA 50a, after disposing a porous body as a material of the anode side gas diffusion layer 21d on the catalyst layer 60a, a water repellent material is applied to the surface of the porous body. At this time, the amount of the water repellent material applied to the portion corresponding to the overlapping portion 80 is reduced compared to the other portions. Then, as described above, the overlap corresponding portion 71d is configured to have a smaller thickness than other portions. Further, for example, when the porous body is crimped, the thickness corresponding to the overlapping portion 71d is smaller than that of the other portion by applying a larger load to the portion corresponding to the overlapping portion or pressing the porous body for a longer time. It can also be configured.

  The cathode side has the same configuration, and in the cathode side gas diffusion layer 21e, the overlap corresponding portion 71e corresponding to the overlap portion 80 is configured to be thinner than the other portions. The height of the upper surface of the overlap corresponding portion 71e is substantially the same as the height of the upper surface of other portions. The cathode side gas diffusion layer 21e is formed in the same manner as the anode side gas diffusion layer 21d.

  In the separator 25a, unlike the anode facing plate 22 (FIG. 3) of the first embodiment, the anode facing plate 22a is not provided with a recess in a portion facing the overlap corresponding portion 71d. Similarly, the cathode facing plate 24a is not provided with a recess in a portion facing the overlap corresponding portion 71e. In the present embodiment, the above-described overlap corresponding portions 71d and 71e correspond to corresponding regions in the claims.

  In the fuel cell of the second embodiment having the above-described configuration, the gas diffusion layers 21d and 21e are configured so that the portion corresponding to the overlapping portion 80 does not protrude as compared with the other portions. Accordingly, the anode facing plate 22a and the anode side gas diffusion layer 21d are in contact with each other over substantially the entire surface, and the cathode facing plate 24a and the cathode side gas diffusion layer 21e are in contact with each other over substantially the entire surface. Become. Therefore, the fuel cell of the second embodiment also has the same effect as the fuel cell 20 of the first embodiment.

C. Variations:
In addition, elements other than the elements claimed in the independent claims among the constituent elements in each of the above embodiments are additional elements and can be omitted as appropriate. The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

C1. Modification 1:
In the first embodiment described above, the thickness of the portion corresponding to the overlapping portion 80 in the separator 25 is configured to be smaller than the thickness of the other portions, and the overlapping portion 80 is formed in the gas diffusion layers 21a and 21c. Corresponding portions (projections 71a, 71c) had substantially the same thickness as the other portions. In the second embodiment, the gas diffusion layers 21d and 21e are configured such that the portions corresponding to the overlapping portion 80 (overlapping corresponding portions 71d and 71e) are smaller in thickness than the other portions. In the separator 25a, the thickness of the portion corresponding to the overlapping portion 80 was the same as the thickness of the other portions. The present invention is not limited to these, and in either the separator or the gas diffusion layer, the thickness of the portion corresponding to the overlapping portion 80 may be configured to be smaller than the thickness of the other portion. it can. Even in such a configuration, it is possible to suppress a large fastening load from being concentrated on a portion corresponding to the overlapping portion 80.

C2. Modification 2:
In each of the above-described embodiments, the seal-integrated MEA 21 is configured as a so-called MEGA (membrane-electrode-diffusion layer assembly) including a gas diffusion layer, but instead, a gas diffusion is used. It can also be configured as a so-called membrane-electrode assembly in which the layer is a separate member. In this case, in the second embodiment, in the gas diffusion layer member (carbon paper, metal porous body, etc.), the thickness of the portion corresponding to the overlapping portion 80 is made smaller than the other portions in advance. It is also possible to manufacture a fuel cell by processing and laminating each member (MEA, gas diffusion layer member and separator).

C3. Modification 3:
In each of the above-described embodiments, the separators 25 and 25a have a three-layer structure in which three plates 23, 24 (24a) and 25 (25a) are overlapped. It can also be composed of any number of plates, such as two or four. Even in such a configuration, in the plate facing the gas diffusion layers 21a and 21c, the concave portions are formed in the portions facing the convex portions 71a and 71c formed on the gas diffusion layers 21a and 21c. The same effect as that of the fuel cell 20 of the first embodiment can be obtained.

C4. Modification 4:
In each of the above-described embodiments, the two protective films fa and fc are configured to overlap the catalyst layers 60a and 60c, respectively, in the overlapping portion 80, but instead of the protective films fa and fc, The catalyst layers 60a and 60c may be overlaid on top of each other. That is, as the seal-integrated MEA, an MEA manufactured by forming the catalyst layers 60a and 60c after disposing the protective films fa and fc on the end portion of the electrolyte membrane 21b can be used for the fuel cell of the present invention.

C5. Modification 5:
In each of the above-described embodiments, the fuel cell 20 is configured by laminating a plurality of seal-integrated MEAs 21 and separators 25. Instead of this, one seal-integrated MEA 21 and this seal-integrated MEA 21 are combined. It can also be comprised with the two separators 25 arrange | positioned on both sides.

The disassembled perspective view of the fuel cell as one Example of this invention. Explanatory drawing which shows the AA cross section shown in FIG. Explanatory drawing which shows the detailed structure of the area | region X shown in FIG. Explanatory drawing which shows the detail of the cross section of the fuel cell in a 2nd Example. Explanatory drawing which shows an example of the cross section of MEA provided with the conventional protective film.

Explanation of symbols

20 ... Fuel cell 21 ... MEA with integrated seal
21a, 21d ... anode side gas diffusion layer 21b ... electrolyte membrane 21c, 21e ... cathode side gas diffusion layer 21y ... gasket 22, 22a ... anode facing plate 23 ... intermediate plate 24, 24a ... cathode facing plate 25, 25a ... separator 31a ... Fuel gas supply manifold 31b ... Oxidant gas supply manifold 50 ... MEA
51 ... Gasket 60a ... Anode-side catalyst layer 60c ... Cathode-side catalyst layer 71a, 71c ... Convex part 71d, 71e ... Overlapping part 74a, 71c ... Concave part 80 ... Overlapping part 90 ... Non-catalyst layer region 211a, 221a, 231a, 241a ... Fuel gas supply manifold formation part 211b, 221b, 231b, 241b ... Fuel gas discharge manifold formation part 212a, 222a, 232a, 242a ... Oxidant gas supply manifold formation part 212b, 222b, 232b, 242b ... Oxidant gas discharge manifold Forming portions 213a, 223a, 243a ... Cooling medium supply manifold forming portions 213b, 223b, 243b ... Cooling medium discharge manifold forming portions 225 ... Fuel gas supply holes 226 ... Fuel gas discharge holes 239 ... Cooling medium flow path forming portions 235 ... Fuel Gas supply flow path forming part 236 ... Fuel gas discharge flow path forming part 237 ... Oxidant gas supply flow path forming part 238 ... Oxidant gas discharge flow path forming part 245 ... Oxidant gas supply hole 246 ... Oxidant gas discharge hole 255 ... Fuel gas supply channel 257 ... Oxidant gas supply channel MEA21 ... Integrated seal X ... Area fa ... Anode-side protective film fc ... Cathode-side protective film

Claims (1)

A fuel cell,
An electrolyte membrane;
A catalyst layer laminated on the electrolyte membrane;
A gas diffusion layer disposed on the opposite side of the electrolyte membrane from the catalyst layer;
A protective film for the electrolyte membrane that covers a region of the electrolyte membrane where the catalyst layer is not laminated and has an overlapping portion that overlaps the catalyst layer;
A separator disposed opposite to the gas diffusion layer;
With
At least one of the separator and the gas diffusion layer is configured so that the thickness in the stacking direction is smaller in the corresponding region corresponding to the overlapping portion than in other regions excluding the corresponding region,
The electrolyte membrane, the catalyst layer, the protective film, and the gas diffusion layer are configured as a membrane electrode assembly,
The protective film is not in contact with the electrolyte membrane in a region where the catalyst layer and the electrolyte membrane are laminated ,
The separator is configured such that the thickness in the stacking direction is smaller in the corresponding region than in other regions excluding the corresponding region,
The corresponding region is a fuel cell configured by a concave curved surface .

Images