JP2008034383A - Sealing structure of fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the bending deformation and cracks of a polymer electrolyte membrane 11, and to secure required seal surface pressure in a sealed structure for sandwiching the polymer electrolyte membrane 11 in a membrane electrode assembly 10 with a first gasket 30 and a second gasket 40 from both sides. <P>SOLUTION: The first gasket 30 has a seal protrusion 31 brought into close contact with the polymer electrolyte membrane 11, and the second gasket 40 has a flat seal surface 41 at a thin part having a thickness (t) of 0.02-0.1 mm and is brought into close contact with the polymer electrolyte membrane 11 on the seal surface 41, thus restraining the dispersion of the surface pressure of the second gasket 40 to the polymer electrolyte membrane 11 by compressing the seal protrusion 31. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sealing structure for sealing between a polymer electrolyte membrane of a membrane electrode assembly and separators disposed on both sides thereof in a fuel cell.

  A fuel cell is a stack in which a plurality of fuel cell cells are sandwiched between separators on both sides in the thickness direction of a membrane electrode assembly (MEA) in which a pair of catalyst electrode layers are provided on both sides of a polymer electrolyte membrane (ion exchange membrane) It has become. Then, an oxidizing gas (oxygen) is supplied to one catalyst electrode layer from an oxidizing gas passage formed on one surface of each separator, and a fuel gas (hydrogen) is formed on the other surface of each separator. Electric power is generated by an electrochemical reaction that is the reverse reaction of water electrolysis, that is, a reaction that generates water from hydrogen and oxygen, which is supplied from the flow path to the other catalyst electrode layer.

  In this type of fuel cell, it is necessary to seal fuel gas, oxidizing gas, water discharged from the cathode surface, excess oxidizing gas, refrigerant, and the like, and a gasket for this purpose is provided in each fuel cell. It is well known that the gasket is made of a rubber-like elastic material and is integrally provided on the surface of the separator and is in close contact with the surface of the membrane electrode assembly.

  FIG. 13 is a partial cross-sectional view showing a fuel cell sealing structure according to the prior art in a separated state. In FIG. 13, reference numeral 110 is a polymer electrolyte membrane (proton membrane) 111 and laminated on both sides thereof. The membrane electrode assembly (MEA) provided with the catalyst electrode layer 112 and the gas diffusion layer (GDL) 113, and the separator 120 is overlapped on both sides of the membrane electrode assembly 110 to constitute the fuel cell 100. The

  In the membrane electrode assembly 110, the periphery of the polymer electrolyte membrane 111 projects from the periphery of the catalyst electrode layer 112 and the gas diffusion layer 113, and the projecting portion 111a is provided integrally with the separators 120 on both sides thereof. The gasket 130 is in close contact. The gasket 130 is made of a rubber-like elastic material, and it is known to form a seal protrusion 131 in order to obtain a required surface pressure.

  However, since the polymer electrolyte membrane 111 in the membrane electrode assembly 110 is thin and poor in rigidity, the polymer electrolyte membrane 111 (the overhang portion 111a) is in a state where a large number of fuel cells 100 are stacked and tightened and assembled as a stack. If the gaskets 130 and 130 on both sides of the above have a slight deviation due to assembly accuracy (offset), not only can the required sealing surface pressure be secured due to the deviation δ of the surface pressure maximum due to the seal protrusion 131, There is a problem that the polymer electrolyte membrane 111 is deformed or damaged due to a bending moment.

Therefore, as a method for preventing the bending deformation and breakage of the polymer electrolyte membrane 111 due to such an offset, one of the gaskets 130 and 130 is a flat seal without a seal protrusion, for example, the following patent It is disclosed in Document 1.
JP 2005-276820 A

  However, in this case, although the required surface pressure can be secured on the seal surface by the seal protrusion, the surface pressure is reduced on the flat seal side as compared with the seal protrusion side, and the required sealability cannot be obtained. There's a problem.

  The present invention has been made in view of the above points, and the technical problem is that a polymer electrolyte in a sealed structure in which a polymer electrolyte membrane of a membrane electrode assembly is sandwiched between gaskets from both sides. In addition to preventing bending deformation and breakage of the membrane, it is necessary to ensure a required seal surface pressure.

  As a means for effectively solving the technical problem described above, the fuel cell sealing structure according to the invention of claim 1 is configured such that the polymer electrolyte membrane of the membrane electrode assembly is disposed on one side in the thickness direction. In a sealing structure sandwiched between a first gasket made of a rubbery elastic material provided integrally with a separator and a second gasket made of a rubbery elastic material provided integrally with a separator disposed on the other side in the thickness direction The first gasket has a seal protrusion that is in close contact with the polymer electrolyte membrane, and the second gasket has a flat seal surface that is in close contact with the polymer electrolyte membrane, Is 0.02 to 0.1 mm.

  According to the above configuration, the compression reaction force of the seal ridge by bringing the seal ridge in the first gasket into close contact with the polymer electrolyte membrane in the required compression state causes the second gasket to pass through the polymer electrolyte membrane. However, by setting the thickness of the second gasket to 0.02 to 0.1 mm, compression deformation is suppressed, so that the dispersion of the surface pressure with respect to the polymer electrolyte membrane is suppressed and the bending of the polymer electrolyte membrane is suppressed. Deformation is also suppressed.

  Here, the upper limit of the wall thickness of the second gasket is defined as 0.1 mm, because a rubber-like elastic material having a hardness of JIS A 30 to 80 is usually used for this type of gasket. In the hardness range, when the thickness of the second gasket exceeds 0.1 mm, the surface pressure of the second gasket remains the same even if the compression amount of the first gasket against the seal projection is increased. This is because it is not equal to or greater than. In addition, the lower limit of the thickness of the second gasket is defined as 0.02 mm. If the thickness is less than 0.02 mm, the surface roughness of the separator or the polymer electrolyte membrane cannot be filled. This is because a gap leak occurs.

  The fuel cell sealing structure according to the invention of claim 2 is characterized in that the second gasket described in claim 1 is formed by applying a rubber solution or liquid rubber to the surface of the separator, using a doctor blade method, a stamp method, a screen printing method, And it apply | coats and hardens | cures by the method selected from the inkjet coating method.

  In a fuel cell sealing structure according to a third aspect of the present invention, the second gasket according to the first aspect is provided in a gasket mounting groove formed in the separator, and the first gasket among the second gaskets A thick wall portion having a deep groove formed on the bottom surface of the gasket mounting groove is provided at a position shifted in the width direction from a portion facing the seal protrusion of the gasket.

  According to the fuel cell sealing structure of the present invention, the thickness of the second gasket facing the seal protrusion of the first gasket through the polymer electrolyte membrane is set to 0.02 to 0.1 mm. Dispersion of the surface pressure of the second gasket with respect to the molecular electrolyte membrane can be suppressed, so that a required seal surface pressure can be ensured, and further, bending deformation and breakage of the polymer electrolyte membrane can be prevented.

  In the present invention, the second gasket having a wall thickness of 0.02 to 0.1 mm can be easily provided on the surface of the separator by using a doctor blade method, a stamp method, a screen printing method, or an ink jet coating method.

  In the present invention, the second gasket is provided in the gasket mounting groove formed in the separator, and the thickness of the deep groove formed in the gasket mounting groove is shifted in the width direction from the portion facing the seal protrusion of the first gasket. If the structure has a meat part, during the molding, by injecting a molding rubber solution or liquid rubber into the deep groove, the flow of the material in the gasket mounting groove (shaping) is performed well, Even with the injection molding method, a thin gasket having a thickness of 0.02 to 0.1 mm can be easily integrally formed on the separator.

  Hereinafter, preferred embodiments of a sealing structure for a fuel cell according to the present invention will be described with reference to the drawings. FIG. 1 is a partial cross-sectional view showing a fuel cell sealing structure according to a first embodiment of the present invention in a separated state.

  In FIG. 1, reference numeral 10 denotes a membrane electrode assembly (MEA) having a polymer electrolyte membrane (proton membrane) 11 and a catalyst electrode layer 12 and a gas diffusion layer (GDL) 13 provided on both sides in a laminated state. The separators 20A and 20B are overlapped on both sides of the membrane electrode assembly 10 to constitute the fuel cell 1.

  In the membrane electrode assembly 10, the periphery of the polymer electrolyte membrane 11 protrudes from the periphery of the catalyst electrode layer 12 and the gas diffusion layer 13, and the protruding portion 11 a is provided integrally with one separator 20 </ b> A. By being sandwiched between one gasket 30 and a second gasket 40 provided integrally with the other separator 20B, fuel gas (hydrogen), oxidizing gas, or an electrochemical reaction thereof is generated and discharged. Water, excess oxidizing gas, refrigerant, and the like are sealed so as not to leak from the respective flow paths.

  FIG. 2 is a view showing the surface of the separator to which the first or second gasket is attached. In FIG. 2, reference numeral 20a is a region serving as a power generation unit in which a large number of flow channel grooves for flowing fuel gas or oxidizing gas are formed, and 20b to 20d are flow channel holes (manifolds). And the 1st gasket 30 and the 2nd gasket 40 are the part provided so that the area | region 20a used as an electric power generation part and the opening part of the flow-path hole 20b, and the opening part of other flow-path holes 20c and 20d. Each part is provided so as to surround it.

The first gasket 30 and the second gasket 40 are selected from ethylene propylene rubber (EPDM), silicone rubber (VMQ), fluorine rubber (FKM), perfluoro rubber (FFKM), etc., and have a hardness of JIS A 30 to 80, preferably JIS
A It is made of 40-60 rubber-like elastic material.

  Among them, the first gasket 30 has a seal protrusion 31 having a mountain-shaped cross section, and is formed by the usual compression molding, LIM molding or SIM molding using the liquid rubber of the rubber-like elastic material described above. Then, it can be affixed to the surface of the separator 20A, or can be integrally formed on the surface of the separator 20A.

  Further, the second gasket 40 has a width W larger than the close width of the seal protrusion 31 of the first gasket 30 with respect to the overhanging portion 11a of the polymer electrolyte membrane 11, and a sealing surface in close contact with the overhanging portion 11a. 41 is flat, and preferably the wall thickness t is 0.02 to 0.1 mm. Such a thin film-like second gasket 40 is formed by using a liquid rubber or a rubber solution of the rubber-like elastic material described above by a method selected from a doctor blade method, a stamp method, a screen printing method, and an ink jet coating method. It can shape | mold by apply | coating to the surface of 20B and making it harden | cure.

  In the above configuration, in the state where a large number of fuel cells 1 are stacked and tightened with bolts and nuts (not shown) and assembled as a fuel cell stack, the overhanging portion 11a of the polymer electrolyte membrane 11 in the membrane electrode assembly 10 is the first. Between the sealing protrusion 31 of the gasket 30 and the flat sealing surface 41 of the second gasket 40.

  Here, since the seal protrusion 31 of the first gasket 30 is in a required compression state, and the polymer electrolyte membrane 11 is thin (about 0.1 mm) and has low rigidity, the reaction force due to compression of the seal protrusion 31 is A compressive force in the thickness direction is applied to the second gasket 40 via the protruding portion 11a of the polymer electrolyte membrane 11. According to the present invention, since the second gasket 40 has a wall thickness t of 0.02 to 0.1 mm, compression deformation is suppressed, so that the dispersion of the surface pressure with respect to the protruding portion 11a is suppressed, that is, the sealing surface. Of 41, the peak surface pressure of the portion facing the seal protrusion 31 is the peak surface pressure of the seal protrusion 31 with respect to the projecting portion 11a, and the required sealing performance can be ensured. For this reason, bending deformation of the overhanging portion 11a is also prevented.

  Moreover, in a state where a large number of fuel cells 1 are stacked and assembled, the first gaskets 30 on both sides of the polymer electrolyte membrane 11 (the overhanging portion 11a) are caused by dimensional accuracy of the separators 20A and 20B, errors in assembly accuracy, and the like. Even if a slight shift (offset) occurs between the second gasket 40 and the second gasket 40, no bending moment is generated in the protruding portion 11a as in the case of being sandwiched between the seal protrusions.

  Next, FIG. 3 is a partial sectional view showing an example in which the fuel cell sealing structure according to the first embodiment described above is applied to a structure in which the overhanging portion 11a of the polymer electrolyte membrane 11 is reinforced with a reinforcing film 14 in a separated state. It is. That is, in this example, a reinforcing film 14 made of a synthetic resin or the like is attached to both surfaces of the protruding portion 11a of the polymer electrolyte membrane 11 in order to ensure the required rigidity. 11 is sandwiched between the sealing protrusion 31 of the first gasket 30 and the flat sealing surface 41 of the second gasket 40 via the reinforcing films 14 and 14.

  Next, FIG. 4 is a partial cross-sectional view showing the fuel cell sealing structure according to the second embodiment of the present invention in a separated state.

  In this embodiment, the difference from the first embodiment is that the raised portions 21 and 22 are stepped on the separators 20A and 20B facing the protruding portion 11a of the polymer electrolyte membrane 11, and the first gasket 30 is formed. The second gasket 40 is provided in the gasket mounting groove 24 formed in the protruding portion 22 of the separator 20B, and the second gasket 40 is provided in the gasket mounting groove 24 formed in the protruding portion 22 of the separator 20B.

  Specifically, the raised height of the raised portion 21 formed in the separator 20A is substantially equal to the sum of the thicknesses of the catalyst electrode layer 12 and the gas diffusion layer 13 in the membrane electrode assembly 10, and the first gasket 30. The base 32 is integrally bonded (molded) to the inner surface of the gasket mounting groove 23 formed in the raised portion 21, and the seal protrusion 31 rising from the base 32 protrudes higher than the raised portion 21. .

  Further, the height of the raised portion 22 formed on the other separator 20B is substantially the same as the sum of the thicknesses of the catalyst electrode layer 12 and the gas diffusion layer 13 in the membrane electrode assembly 10, and the second gasket 40 Is a thin film having a thickness of 0.02 to 0.1 mm, and is integrally bonded (molded) to the gasket mounting groove 24 formed in the raised portion 22, and the flat sealing surface 41 is formed on the raised portion 22. And the same plane or slightly higher. That is, the depth of the gasket mounting groove 24 is equal to or less than the thickness of the second gasket 40.

  Even in the above configuration, in the state where a large number of fuel cells 1 are stacked and tightened with bolts and nuts (not shown) and assembled as a fuel cell stack, the overhanging portion 11a of the polymer electrolyte membrane 11 in the membrane electrode assembly 10 is It is sandwiched between the seal protrusion 31 of the first gasket 30 and the flat seal surface 41 of the second gasket 40.

  Since the second gasket 40 has a wall thickness t of 0.02 to 0.1 mm, compression deformation is suppressed, so that the peak surface pressure of the portion of the seal surface 41 that faces the seal protrusion 31 is reduced to the polymer electrolyte. The required sealing performance can be ensured substantially equal to the peak surface pressure of the seal protrusion 31 with respect to the protruding portion 11 a of the film 11. For this reason, bending deformation of the overhanging portion 11a is also prevented, and even if the first gasket 30 and the second gasket 40 are slightly shifted (offset) from each other, the overhanging portion 11a is sandwiched between the seal protrusions. No bending moment is generated as in the case.

  In the case where the protruding portion 22 is not formed on the separator 20B (the first embodiment shown in FIG. 1 or FIG. 3 described above), the gas diffusion layer 13 and the catalyst electrode layer 12 on the separator 20B side are If the thickness after stack assembly and the wall thickness t of the second gasket 40 are not equal, between the protruding portion 11a of the polymer electrolyte membrane 11 and the portion sandwiched between the gas diffusion layer 13 and the catalyst electrode layer 12 , Bending stress due to the height difference in the stacking direction is generated. On the other hand, as in the second embodiment, the separator 20B is provided with a raised portion 22, the gasket mounting groove 24 formed in the raised portion 22 is provided with the second gasket 40, and the sealing surface 41 is the same as the raised portion 22. Even if the thickness t of the gas diffusion layer 13 and the catalyst electrode layer 12 on the separator 20B side and the thickness of the second gasket 40 is not equal, the height of the raised portion 22 and the gasket mounting groove are provided so as to form a plane. By setting the depth of 24 appropriately, the polymer electrolyte membrane 11 can be laminated in a flat state.

  In the second embodiment, the first and second gaskets 30 and 40 are provided in the gasket mounting grooves 23 and 24 formed in the raised portions 21 and 22 of the separators 20A and 20B, so By tightening the stacked fuel cells 1 until the portions 21 and 22 come into contact with the overhanging portions 11a of the polymer electrolyte membrane 11, gaps between the separator 20A, the membrane electrode assembly 10, and the separator 20B in each fuel cell 1 The amount of compression of the first gasket 30 with respect to the seal protrusion 31 can be easily managed.

  Next, FIG. 5 is a partial cross-sectional view showing an example in which the fuel cell sealing structure according to the second embodiment described above is applied to a structure in which the overhanging portion 11a of the polymer electrolyte membrane 11 is reinforced with the reinforcing film 14, in a separated state. It is. That is, in this example, a reinforcing film 14 made of a synthetic resin or the like is attached to both surfaces of the protruding portion 11a of the polymer electrolyte membrane 11 in order to ensure the required rigidity. 11 is sandwiched between the sealing protrusion 31 of the first gasket 30 and the flat sealing surface 41 of the second gasket 40 via the reinforcing films 14 and 14.

  Next, FIG. 6 is a view showing the surface of the separator to which the second gasket is attached in the fuel cell sealing structure according to the third embodiment of the present invention, and FIG. 7 is a sectional view taken along the line VII-VII in FIG. It is a fragmentary sectional view shown in a separated state.

  In this embodiment, similarly to the second embodiment described above, the raised portions 21 and 22 are formed in steps on the portions of the separators 20 </ b> A and 20 </ b> B facing the protruding portion 11 a of the polymer electrolyte membrane 11, and the first gasket 30 is formed. Is provided in the gasket mounting groove 23 formed in the raised portion 21 of the separator 20A, and the second gasket 40 is provided in the gasket mounting groove 24 formed in the raised portion 22 of the separator 20B. In the third embodiment, the second gasket 40 is different from the second embodiment shown in FIG. 4 or FIG. 5 in that the second gasket 40 has a thin-walled body portion 42 having a wall thickness t of 0.02 to 0.1 mm. FIG. 6 shows a thick portion 43 formed by the deep groove 25 formed in the bottom surface of the gasket mounting groove 24 at a position shifted in the width direction from the portion of the main body portion 42 facing the seal protrusion 31 of the first gasket 30. In this way, it is formed continuously over the entire length in the extending direction.

  Preferably, in the stacked / assembled state of the fuel cell 1, the seal protrusion 31 does not face the thick portion 43 even if the first gasket 30 and the second gasket 40 are offset to some extent. Thus, the thick part 43 is formed along the one side edge part of the 2nd gasket 40 in anticipation of the offset amount which can generate | occur | produce.

  As described above, since the thick portion 43 is formed at a position shifted in the width direction from the portion facing the seal protrusion 31 of the first gasket 30, in the stacked / assembled state of the fuel cell unit 1, The compression reaction force of the ridge 31 is applied as a compressive force in the thickness direction to the thin main body portion 42 of the second gasket 40 via the protruding portion 11a of the polymer electrolyte membrane 11. For this reason, as in the first or second embodiment, the dispersion of the surface pressure with respect to the overhanging portion 11a is suppressed, the required sealing performance can be ensured, and the bending deformation of the overhanging portion 11a is also prevented.

  According to this embodiment, the second gasket 40 can be formed by an injection molding method. This will be further described. FIG. 8 is a partial cross-sectional view showing the molding process of the second gasket by the injection molding method, and reference numeral 50 in the figure is a mold that is in contact with and separated from the separator 20B. The mold 50 injects a molding rubber solution or liquid rubber (hereinafter referred to as a molding material) into a molding cavity 51 defined between the gasket 20 and the gasket mounting groove 24 of the separator 20B when the mold is closed. A number of runners 52 are opened at predetermined intervals in the extending direction of the molding cavity 51. The opening on the molding cavity 51 side of the runner 52 is a gate 53 with a narrowed flow path, and this gate 53 is formed so as to be positioned on the deep groove 25 in the illustrated mold closed state. Yes.

  That is, when the second gasket 40 is formed integrally with the separator 20B, the mold cavity 51 is defined between the separator 20B and the separator 20B by closing the mold as shown in FIG. A molding material is injected into the cavity 51 through the gate 53.

  Here, assuming that the deep groove 25 does not exist in the molding cavity 51, in this case, the injected molding material is less likely to flow smoothly in the extending direction in the narrow molding cavity 51 of 0.02 to 0.1 mm. For this reason, molding defects are likely to occur. On the other hand, in the method shown in FIG. 8, since the molding material from each gate 53 is injected toward the deep groove 25 and the cross-sectional area of the molding cavity 51 is increased in the deep groove 25, the molding material is molded. Smoothly flow in the extending direction of the cavity 51 for use, merge with each other, and further shaped from the deep groove 25 to the shallow groove portion in the entire extending direction. For this reason, it can be easily integrally formed with the separator 20B by an injection molding method.

  9 to 13 show the test results. Of these, FIG. 9 shows the second gasket with respect to the sealing structure by the first and second gaskets 30 and 40 shown in FIG. 4 described above. A line showing the result of FEM analysis of the surface pressure with respect to the protruding portion 11a of the polymer electrolyte membrane 11 in relation to the amount of compression of the seal protrusion 31 of the first gasket 30 when the thickness t of 40 is 0.1 mm. 10 is a diagram when the thickness t of the second gasket 40 is 0.3 mm, FIG. 11 is a diagram when the thickness t is also 0.5 mm, and FIG. FIG. 6 is a diagram showing the relationship between the wall thickness t of the second gasket 40 and the surface pressure with respect to the overhanging portion 11a of the polymer electrolyte membrane 11 when the compression amount of the strip 31 is 0.6 mm.

  As the conditions for this test, the first and second gaskets 30 and 40 are made of a rubber-like elastic material having a hardness of JIS A 50, and the polymer sandwiched between the first and second gaskets 30 and 40 is used. The electrolyte membrane 11 had a thickness of 0.1 mm, an elastic modulus of 2 GPa, a Poisson's ratio of 0.35, and an analysis temperature of 25 ° C.

  As is apparent from the test results, when the wall thickness t of the second gasket 40 is 0.5 mm or 0.3 mm, the seal surface pressure of the second gasket 40 is the seal protrusion of the first gasket 30. The seal surface pressure of the second gasket 40 is increased as the wall thickness t is decreased, and the difference from the seal surface pressure of the seal protrusion 31 is decreased. In this case, as shown in FIG. 9, when the compression amount is 0.5 mm or more, the seal surface pressure on the seal protrusion 31 side and the seal surface pressure on the second gasket 40 side are almost balanced. Therefore, it can be seen that the thickness t of the second gasket 40 may be 0.1 mm or less.

It is a fragmentary sectional view which shows the sealing structure of the fuel cell by the 1st form of this invention in the isolation | separation state. It is a figure which shows the surface of the separator which attached the 1st or 2nd gasket in the sealing structure of the fuel cell by the 1st form of this invention. It is a fragmentary sectional view which shows the example which applied the sealing structure of the fuel cell by a 1st form to what reinforced the overhang | projection part of the polymer electrolyte membrane with the reinforcement film in a separated state. It is a fragmentary sectional view which shows the sealing structure of the fuel cell by the 2nd form of this invention in the isolation | separation state. It is a fragmentary sectional view which shows the example which applied the sealing structure of the fuel cell by a 2nd form to what reinforced the overhang | projection part of the polymer electrolyte membrane with the reinforcement film in a separated state. It is a figure which shows the surface of the separator which attached the 2nd gasket in the sealing structure of the fuel cell by the 3rd form of this invention. It is a fragmentary sectional view which shows the cross section of the VII-VII position in FIG. 6 in the isolation | separation state. It is a fragmentary sectional view which shows the formation process of the 2nd gasket shown by FIG. It is a diagram which shows the result of having performed the FEM analysis of the surface pressure with respect to a polymer electrolyte membrane in relation to the compression amount of a seal protrusion when the thickness t of a 2nd gasket is 0.1 mm. It is a diagram which shows the result of having performed the FEM analysis of the surface pressure with respect to a polymer electrolyte membrane in relation to the amount of compression of a seal protrusion when the wall thickness t of a 2nd gasket is 0.3 mm. It is a diagram which shows the result of having performed the FEM analysis on the surface pressure with respect to a polymer electrolyte membrane in relation to the compression amount of a seal protrusion when the thickness t of a 2nd gasket is 0.5 mm. FIG. 6 is a diagram showing the relationship between the wall thickness t of the second gasket and the contact pressure with respect to the overhanging portion of the polymer electrolyte membrane when the amount of compression of the seal protrusion is 0.6 mm. It is a fragmentary sectional view which shows the sealing structure of the fuel cell by a prior art in a separated state.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell 10 Membrane electrode assembly 11 Polymer electrolyte membrane 11a Overhang | projection part 12 Catalytic electrode layer 13 Gas diffusion layer 14 Reinforcement film 20A, 20B Separator 21, 22 Raised part 23, 24 Gasket mounting groove 25 Deep groove 30 First gasket 31 Sealing ridge 32 Base 40 Second gasket 41 Seal surface 42 Main body 43 Thick part 50 Mold 51 Molding cavity 52 Runner 53 Gate

Claims (3)

  A first gasket (30) made of a rubber-like elastic material in which a polymer electrolyte membrane (11) of a membrane electrode assembly (10) is integrally provided on a separator (20A) arranged on one side in the thickness direction. In the sealing structure sandwiched by the second gasket (40) made of a rubber-like elastic material provided integrally with the separator (20B) disposed on the other side in the thickness direction, the first gasket (30) is: It has a seal protrusion (31) in close contact with the polymer electrolyte membrane (11), and the second gasket (40) is a flat seal surface (41 in close contact with the polymer electrolyte membrane (11). And a thickness (t) of 0.02 to 0.1 mm.   The second gasket (40) is coated with a rubber solution or liquid rubber on the surface of the separator (20B) by a method selected from a doctor blade method, a stamp method, a screen printing method, and an ink jet coating method, and is cured. The fuel cell sealing structure according to claim 1, wherein the fuel cell sealing structure is provided.   A second gasket (40) is provided in the gasket mounting groove (24) formed in the separator (20B). Of the second gasket (40), the seal protrusion ( 31. A thick portion (43) formed by a deep groove (25) formed in a bottom surface of the gasket mounting groove (24) at a position shifted in a width direction from a portion facing 31). Fuel cell sealing structure.

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