JP2001319666A - Fuel cell and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell for allowing the improvement of sealability between an electrode membrane structure and a separator and its manufacturing method. SOLUTION: A cell of the fuel cell composed of a solid polymer electrolyte membrane 18 and at least an anode electrode 22 and a cathode electrode 20 at each opposed end thereof is configured to be pinched between by the first separator 14 and the second separator 16. Around the solid polymer electrolyte membrane 18 is provided a projection 18a protruding from the anode electrode 22 periphery and the cathode electrode 20 periphery. Each groove portion 28 is provided in a position corresponding to the projection 18a of the solid polymeric electrolyte membrane 18, which is a periphery in the surface of respective separators 14, 16. The fuel cell is pinched between by the separators 14, 16 with a fluid sealant S applied to the groove portion 28 in a close contact with the projection 18a of the solid polymer electrolyte membrane 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell in which an electrode membrane structure composed of a solid polymer electrolyte membrane and anode-side diffusion electrodes and cathode-side diffusion electrodes on both sides thereof is sandwiched between a pair of separators and a fuel cell. The present invention relates to a manufacturing method, and more particularly to a fuel cell capable of reliably sealing an electrode membrane structure between separators, and a manufacturing method thereof.

[0002]

2. Description of the Related Art In a fuel cell, an electrode membrane structure composed of a solid polymer electrolyte membrane, an anode-side diffusion electrode and a cathode-side diffusion electrode on both sides thereof is sandwiched between a pair of separators. There are things. When a fuel gas (for example, hydrogen gas) is supplied to the reaction surface of the anode-side diffusion electrode, the hydrogen is ionized here and moves to the cathode-side diffusion electrode side via the solid polymer electrolyte membrane. The electrons generated during this time are taken out to an external circuit and used as DC electric energy. At the cathode electrode, an oxidizing gas (for example,
Hydrogen-containing air)
The electrons and oxygen react to produce water.

An example of this will be described with reference to FIG. 17. In the figure, reference numeral 1 denotes a solid polymer electrolyte membrane, and this solid polymer electrolyte membrane 1 is provided with gas diffusion electrodes (anode diffusion electrode and cathode diffusion electrode) 2 from both sides. The fuel cell unit 4 is sandwiched between the fuel cell units 3. A sheet-like gasket 5 having an opening at a position corresponding to the reaction surface of the fuel cell 4 is disposed on both sides of the fuel cell 4. Wrap,
In a state where the peripheral edge of the fuel cell 4 is pressed via the outer holding member 6, the fuel cells 4 are separated by the separators 7, 7.
(See JP-A-6-325).
777 gazette).

[0004]

In the above conventional fuel cell, the space between the separator 7 and the gas diffusion electrodes 2 and 3 is cut off from the outside by the gasket 5, so that the fuel gas and the oxidation Gas does not leak outside,
In addition, since both are not mixed, power generation can be performed without waste.
In addition, since dimensional variations in the thickness direction of the gas diffusion electrodes 2 and 3 are unavoidable, when a gasket 5 having a fixed size is used to fasten the two, the sealing reaction force differs at each portion. Therefore, there is a problem that uniform sealing properties cannot be secured over the entire circumference between the separator 7 and the gas diffusion electrodes 2 and 3.

In order to ensure uniform sealing, the dimensional accuracy of the separator 7 and the gas diffusion electrodes 2 and 3 must be strictly controlled, leading to a problem that the cost is increased. In addition, the surface pressure of the gasket 5 is lower than that of the gas diffusion electrodes 2 and 3.
There is a problem that unevenness occurs around the separator 7 and a biased bending stress acts on the separator 7.

In particular, when the separator 7 is used as a fuel cell for a vehicle, the thickness of the separator 7 is controlled so that the bending stress acting on the separator 7 does not exceed a predetermined value even when the surface pressure of the gasket 5 varies. However, there is a problem that the fuel cell stack formed by stacking the fuel cells becomes large in size and narrows the cabin space. Therefore, the present invention provides a fuel cell capable of improving the sealing property between the electrode membrane structure and the separator,
An object of the present invention is to provide a method for manufacturing a fuel cell, in which the sealing property between the electrode membrane structure and the separator is easily ensured.

[0007]

Means for Solving the Problems In order to solve the above problems, the invention described in claim 1 is directed to a solid polymer electrolyte membrane (for example, the solid polymer electrolyte membrane 18 in the embodiment).
And anode-side diffusion electrodes (for example, the anode electrode 22 and the second diffusion layer 26 in the embodiment) on both sides thereof and a cathode-side diffusion electrode (for example, the cathode electrode 20 and the first diffusion layer 24 in the embodiment). In a fuel cell in which an electrode membrane structure (for example, the fuel cell 12 in the embodiment) is sandwiched between a pair of separators (for example, the first separator 14 and the second separator 16 in the embodiment), a solid polymer is used. A protruding portion (for example, a protruding portion 18a in the embodiment) protruding from the outer periphery of the anode-side diffusion electrode and the outer periphery of the cathode-side diffusion electrode is provided around the electrolyte membrane, and is an outer peripheral portion in the separator surface, wherein the solid polymer electrolyte is formed. Each groove (for example, groove 2 in the embodiment) is provided at a position corresponding to the protrusion of the film.
8) is provided, and the electrode film structure is sandwiched between a pair of separators in a state where the liquid seal (for example, the liquid seal S in the embodiment) applied to the groove is in close contact with the protruding portion of the solid polymer electrolyte membrane. It is characterized by the following.

[0008] With this configuration, the liquid seal that is in direct contact with the protruding portion provided around the solid polymer electrolyte membrane changes its shape between the solid polymer electrolyte membrane and the separator, and the seal is changed. Following the dimensional variation, it is possible to ensure airtightness between the two by interposing them without any gap between them while maintaining a constant surface pressure inside the groove.

According to a second aspect of the present invention, an electrode membrane structure composed of a solid polymer electrolyte membrane and anode-side diffusion electrodes and cathode-side diffusion electrodes on both sides thereof is sandwiched between a pair of separators. In the method for manufacturing a fuel cell,
A liquid seal is applied to a groove formed in an outer peripheral portion in the separator surface, and the liquid seal before curing is provided around the solid polymer electrolyte membrane and protrudes from the periphery of the anode-side diffusion electrode and the cathode-side diffusion electrode. The electrode film structure is sandwiched between a pair of separators in a state of being in close contact with the portion, and then heated to cure the liquid seal.

[0010] With this configuration, the liquid seal applied to the inside of the groove portion of the separator can sufficiently secure a margin for crushing while maintaining a constant width in the groove portion, so that the solid polymer electrolyte membrane can be formed. It can adhere to the protruding part and can be deformed according to the size of the conformable seal, and is then heated and cured.

The invention described in claim 3 is characterized in that the fuel cell described in claim 1 is for a vehicle. With this configuration, the liquid seal absorbs variations in the seal size between the separator and the protruding portion of the solid polymer electrolyte membrane, thereby preventing the biased force from acting on the separator, and Can be made thinner.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view showing a fuel cell according to an embodiment of the present invention. The fuel cell 10 includes a fuel cell (electrode membrane structure) 12 and a first separator 14 and a second separator 16 sandwiching the fuel cell. A plurality of these are stacked to form a fuel cell stack for a vehicle. It is. The fuel cell 12 includes the solid polymer electrolyte membrane 1
8 and a cathode electrode 20 and an anode electrode 22 provided with the solid polymer electrolyte membrane 18 interposed therebetween, and the cathode electrode 20 and the anode electrode 22
The first gas diffusion layer 24 made of, for example, a porous carbon cloth or a porous carbon paper as a porous layer
And a second gas diffusion layer 26. Here, as the solid polymer electrolyte membrane 18, a perfluorosulfonic acid polymer is used. The cathode electrode 20 and the anode electrode 22 are mainly composed of Pt. The cathode electrode 20 and the first gas diffusion layer 24 constitute a cathode diffusion electrode, and the anode electrode 22 and the second gas diffusion layer 24 constitute an anode diffusion electrode.

The solid polymer electrolyte membrane 18 is provided with protruding portions 18a protruding from the outer circumferences of the cathode electrode 20 and the anode electrode 22 disposed therebetween, and the protruding portions 18a are provided from both sides at positions corresponding to the protruding portions 18a. 1st and 2nd
A liquid seal S, which will be described later, applied to the separators 14 and 16 is in direct contact with the liquid seal S.

As shown in FIG. 3, the first separator 14
In the plane, on the upper side of both ends in the lateral direction located at the outer peripheral edge, an inlet-side fuel gas communication hole 36a for passing a fuel gas such as a hydrogen-containing gas, and an oxidizing gas which is an oxygen-containing gas or air. And an inlet-side oxidant gas communication hole 38a through which the agent gas passes. At the center of both ends in the lateral direction of the first separator 14, an inlet-side cooling medium communication hole 40a for passing a cooling medium such as pure water, ethylene glycol or oil, and an outlet for passing the used cooling medium. The side cooling medium communication hole 40b is provided. Further, an outlet side fuel gas communication hole 36b for passing the fuel gas and an outlet for passing the oxidizing gas are provided on the lower side of both ends in the lateral direction located in the plane of the first separator 14 and at the outer peripheral edge. The side oxidant gas communication hole 38b is connected to the inlet side fuel gas communication hole 36a and the inlet side oxidant gas communication hole 38.
It is provided so as to be diagonal to a.

As shown in FIG. 1, the surface 14a of the first separator 14 facing the cathode electrode 20 is provided with a plurality of, for example, six, independent first oxidizing gas communication holes 38a in the vicinity of the inlet side oxidizing gas communication hole 38a. The first oxidizing gas flow channel groove 42 is provided in the direction of gravity while meandering in the horizontal direction.
The first oxidizing gas passage groove 42 joins the three second oxidizing gas passage grooves 44, and the second oxidizing gas passage groove 44 is close to the outlet-side oxidizing gas communication hole 38b. Terminated.

As shown in FIG. 3, the first separator 14 penetrates the first separator 14, and has one end communicating with the inlet-side oxidant gas communication hole 38a at a surface 14b opposite to the surface 14a. On the other hand, the other end communicates with the first oxidizing gas passage 46 on the surface 14a side and the outlet oxidizing gas communication hole 38b on one side 14b. On the other hand, a second oxidizing gas connection channel 48 whose other end communicates with the second oxidizing gas channel groove 44 on the side of the surface 14 a is provided to penetrate the first separator 14.

As shown in FIG. 4 and FIG. 5, as in the first separator 14, the inlet-side fuel gas communication holes are formed at both lateral sides located in the plane of the second separator 16 and at the outer peripheral edge. 36a, an inlet-side oxidizing gas communication hole 38a, an inlet-side cooling medium communication hole 40a, an outlet-side cooling medium communication hole 40b, an outlet-side fuel gas communication hole 36b, and an outlet-side oxidizing gas communication hole 38b.

On the surface 16a of the second separator 16,
A plurality of, for example, six first fuel gas flow grooves 60 are formed near the inlet side fuel gas communication hole 36a. The first fuel gas passage groove 60 extends in the direction of gravity while meandering in the horizontal direction, and extends in the three second fuel gas passage grooves 6.
2, the second fuel gas passage groove 62 terminates near the outlet side fuel gas communication hole 36b. The second separator 16 has a first fuel gas connection passage 64 communicating the inlet side fuel gas communication hole 36a from the surface 16b to the first fuel gas passage groove 60, and an outlet side fuel gas communication hole 36b. 1
A second fuel gas connection passage 66 communicating from the 6b side to the second fuel gas passage groove 62 is provided through the second separator 16.

As shown in FIGS. 2 and 5, the surface 16b of the second separator 16 has an inlet side cooling medium communication hole 40a and an outlet side cooling medium communication hole 40b within a range surrounded by a liquid seal S described later. A plurality of main flow channel grooves 72a and 72b forming a cooling medium flow channel are formed in the vicinity of the main flow channel. Between the main flow channel grooves 72a and 72b, a plurality of branch flow channel grooves 74 are provided extending in the horizontal direction.
The second separator 16 has an inlet-side cooling medium communication hole 40a.
Cooling medium connecting flow path 7 which communicates with the main flow path groove 72a
6 and a second cooling medium connecting passage 78 communicating the outlet side cooling medium communication hole 40b and the main flow passage groove 72b are provided through the second separator 16.

As shown in FIG. 2, a second separator 1 sandwiching the solid polymer electrolyte membrane 1 is provided at a position corresponding to the protruding portion 18a of the solid polymer electrolyte membrane 18.
A groove 28 is provided on the surface 16a of the sixth anode electrode 22 facing the anode electrode 22, and a liquid seal S is applied to the groove 28. The inlet-side fuel gas communication hole 36a and the inlet-side oxidant gas communication hole 38 on the surface 16a of the second separator 16 are also provided.
a, a groove 30 is also formed around the inlet-side cooling medium communication hole 40a, the outlet-side cooling medium communication hole 40b, the outlet-side fuel gas communication hole 36b, and the outlet-side oxidant gas communication hole 38b. The seal S is applied. Here, the grooves 30 around the inlet-side coolant communication hole 40a and the outlet-side coolant communication hole 40b are formed so as to surround the first coolant connection passage 76 and the second coolant connection passage 78, respectively. Have been.

As shown in FIG. 1, a groove 14 of the surface 16a of the second separator 16 is also formed on the surface 14a of the first separator 14 which sandwiches the fuel cell 12 together with the second separator 16. 28 and groove 3
A groove 28 and a groove 30 are formed at positions corresponding to 0, and a liquid seal S is applied to each of the grooves 28 and 30. Therefore, as shown in FIGS. 2 and 6, each of the liquid seals S applied to the grooves 28 and 30 of the first separator 14 and the second separator 16 sandwiching the fuel cell 12 is the liquid seal S of the groove 28. In S, the protruding portion 18a is sandwiched at a position facing each side and closely adhered to seal the periphery of the fuel cell 12, and the liquid seal S of the groove 30 is closely adhered to each of the communication holes 36a,
The periphery of 36b, 38a, 38b, 40a, 40b is sealed.

As shown in FIG. 5, the second separator 1
The surface 16b of the sixth fuel cell 10 is provided with a groove 34 at a position facing the surface 14b of the first separator 14 when the plurality of fuel cells 10 are stacked and surrounding the branch flow channel 74. 34, a liquid seal S is applied.
The inlet-side fuel gas communication hole 36a, the inlet-side oxidizing gas communication hole 38a, the inlet-side cooling medium communication hole 40a, and the outlet-side cooling medium communication hole 40 on the surface 16b of the second separator 16.
b, a groove 35 is also formed around the outlet side fuel gas communication hole 36b and the outlet side oxidant gas communication hole 38b, and the liquid seal S is applied to the groove 35 as well.

Here, the inlet side fuel gas communication hole 36a
And a groove 35 around the outlet side fuel gas communication hole 36b,
The first fuel gas connection passage 64 and the second fuel gas connection passage 66 are respectively formed so as to surround the first fuel gas connection passage 64 and the second fuel gas connection passage 66. The groove 35 around the inlet-side oxidant gas communication hole 38a and the outlet-side oxidant gas communication hole 38b is formed to communicate with the inlet-side oxidant gas communication hole 38a of the surface 14b of the first separator 14 and the outlet-side oxidant gas communication hole. It is provided so as to surround the hole 38b.

As described above, when the fuel cells 10 are stacked, when the surface 14b of the first separator 14 and the surface 16b of the second separator 16 are superimposed, the inlet side fuel gas communication hole 36a, the inlet side oxidizing gas Communication hole 38a, inlet side cooling medium communication hole 40a, outlet side cooling medium communication hole 40b, outlet side fuel gas communication hole 36b, and outlet side oxidizing gas communication hole 3
8b and around the branch flow channel 74.
The liquid seal S on the sixth side is in close contact with the surface 14b of the first separator 14, thereby ensuring watertightness between the first separator 14 and the second separator 16.

Here, the liquid seal S is made of thermosetting fluorine-based or thermosetting silicone, has a viscosity such that the cross-sectional shape does not change in the applied state, and is cured while maintaining a certain degree of elasticity after the application. Is non-adhesive,
Any of the adhesive properties can be used. A part that needs to be replaced for maintenance or the like, for example, the first separator 1
It is desirable to use a non-adhesive liquid seal S between the fourth surface 14b and the second separator 16 surface 16b. Specifically, the dimensions of the liquid seal S are as follows: the application diameter of the liquid seal S is 0.6 mm, and the seal load is 0.5 (smaller than this, the sealing property is reduced) to 2 (larger than this). Degree. The grooves 28, 30, 34, and 35 are set to have a width of about 2 mm and a depth of about 0.2 mm. These grooves 28, 30, 34, 3
In 5, since the liquid seal S is crushed after the application, the cross-sectional area of the seal is enlarged, a dimensional error in the seal portion is absorbed, and uniform contact can be achieved.

That is, as shown in FIG. 8, when the solid seal S 'is used in a portion which is in close contact with the solid polymer electrolyte membrane 18, the solid seal S' is pressed against the solid polymer electrolyte membrane 18. When the solid seal S ′ is compressed, the solid polymer electrolyte membrane 18 does not slide evenly in the horizontal direction, so that a part of the solid polymer electrolyte membrane 18 is distorted and the sealing property is deteriorated. However, as shown in FIG. For example, the solid polymer electrolyte membrane 18 does not warp during compression, and the liquid seal S is flexibly deformed by the wrinkles of the solid polymer electrolyte membrane 18 so that the sealing property can be secured.

Next, a method of manufacturing the fuel cell 10 will be described with reference to FIGS. As shown in FIG. 9, the grooves 28, 3 on the surface 14a of the first separator 14.
The liquid seal S is applied to the grooves 0 and the grooves 28 and 30 of the second separator 16. After applying the liquid seal S, the first separator 14 and the second separator 16 are stored in a storage rack 80 shown in FIG. 10 for transportation and storage. next,
As shown in FIG. 11, the pre-assembled fuel cell 1
The first separator 14 and the second separator 16 are set in such a manner that the second jig 2 is sandwiched therebetween, and these are set so as to be sandwiched between the holding jigs 82. This holding jig 82
The lower holding jig 82 is configured to be able to move up and down by an automatic elevator 84. Further, the fuel cell 12 is supported by a jig 86 for supporting the periphery thereof, and the first and second separators 1 are provided.
Positioning in the in-plane direction with respect to 4, 16 is performed.

Then, the lower holding jig 82 is raised to separate the fuel cell 12 from the first and second separators 14 and 1.
6, the liquid seal S of the groove 28 is brought into close contact with the protrusion 18 a of the solid polymer electrolyte membrane 18 at a position facing each other, and the fuel cell 12 is sandwiched between the separators 14 and 16. At this time, the liquid seals S of the grooves 30 are in close contact with each other, and the reaction surface and the inlet side fuel gas communication hole 36a, the inlet side oxidant gas communication hole 38a, the inlet side cooling medium communication hole 40a, the outlet side cooling medium Communication hole 40b,
The periphery of the outlet side fuel gas communication hole 36b and the outlet side oxidant gas communication hole 38b are sealed.

Next, as shown in FIG. 12, the fuel cell 12 sandwiched between the first separator 14 and the second separator 16 is heated together with the holding jig 82 in the oven 88 to cure the liquid seal S. . Then, as shown in FIG. 13, the fuel cell 12 and the first and second separators 14,
The fuel cell 10 in which the fuel cell 16 is integrated is removed from the holding jig 82 and cooled. Next, as shown in FIG. 14, the grooves 3 on the surface 16b of the second separator 16 of the fuel cell 10 are formed.
The liquid seal S is applied to the fuel cells 4 and 35, and the surface 14b of the first separator 14 of another fuel cell 10 is superimposed on the surface 16b of the second separator 16 as shown in FIG. It is laminated on the end plate 90 of the stack. When a predetermined number of fuel cells 10 are stacked, an end plate (not shown) is
Then, the fuel cell stack is tightened at 2.

The operation of the fuel cell 10 according to the first embodiment will be described below. The fuel cell 10 is supplied with a fuel gas, for example, a gas containing hydrogen obtained by reforming a hydrocarbon, and as an oxidant gas, air or an oxygen-containing gas (hereinafter also simply referred to as air).
Is supplied, and a cooling medium is supplied to cool the power generation surface. The fuel gas supplied to the inlet-side fuel gas communication hole 36a of the fuel cell 10 is, as shown in FIG.
From the surface 16b side to the surface 1 via the first fuel gas connection flow path 64
6a side and the first side formed on the surface 16a side.
The fuel gas is supplied to the fuel gas channel groove 60.

The fuel gas supplied to the first fuel gas passage groove 60 moves in the direction of gravity while meandering in the horizontal direction along the surface 16a of the second separator 16. At that time, the hydrogen-containing gas in the fuel gas is supplied to the anode 22 of the unit fuel cell 12 through the second gas diffusion layer 26. The unused fuel gas is supplied to the anode 22 while moving along the first fuel gas flow channel groove 60, while the unused fuel gas is supplied to the second fuel gas flow channel groove 62.
Is introduced into the second fuel gas connection flow path 66 through the
After moving to the side b, the outlet side fuel gas communication hole 3 shown in FIG.
6b.

The air supplied to the inlet-side oxidant gas communication hole 38a in the fuel cell stack 10 is supplied to the first oxidizer gas communication passage communicating with the inlet-side oxidant gas communication hole 38a of the first separator 14. The gas is introduced into the first oxidizing gas channel groove 42 through the groove 46. While the air supplied to the first oxidizing gas flow channel groove 42 moves in the direction of gravity while meandering in the horizontal direction, the oxygen-containing gas in the air is removed by the first gas diffusion layer 2.
4 to the cathode side electrode 20. On the other hand, unused air is discharged from the second oxidizing gas connection flow path 48 through the second oxidizing gas flow path groove 44 to the outlet side oxidizing gas communication hole 38b shown in FIG. As a result, power is generated in the fuel cell 10 and, for example, power is supplied to a motor (not shown).

Further, the cooling medium supplied to the fuel cell 10 is introduced into the inlet-side cooling medium communication hole 40a shown in FIG. 1, and then, as shown in FIG. It is supplied to the main channel groove 72a on the surface 16b side via the connection channel 76. The cooling medium cools the power generation surface of the unit fuel cell 12 through a plurality of branch flow grooves 74 branched from the main flow groove 72a, and then joins the main flow groove 72b. Then, the used cooling medium is discharged from the outlet side cooling medium communication hole 40b through the second cooling medium connection flow path 78.

According to the above-described embodiment, the liquid seal S which is in close contact with the protruding portion 18a provided around the solid polymer electrolyte membrane 18 is provided with the solid polymer electrolyte membrane 18 and the first and second separators 14, 16 to follow the variation in the seal size, and the groove portions 28, 30, 3
In the state where a constant surface pressure is ensured in the inner and outer surfaces of the fuel cell 12 and the fuel cell 12, the first and second separators 14 and 16 and the fuel cell 12 can be secured. Between them, a uniform sealing reaction force is obtained over the entire circumference, and uniform sealing properties can be ensured. Therefore, the first and second separators 14 and 1 have good follow-up performance with respect to dimensional errors due to the liquid seal S.
It is not necessary to strictly control the dimensions of the fuel cell 6 and the fuel cell 12 especially in the thickness direction, and the dimensional accuracy can be easily controlled and the cost can be reduced.

The liquid seal S applied to the groove portions 28 of the first and second separators 14 and 16 maintains the width of the liquid seal S within the groove portions 28 while maintaining a constant width.
Since it can be closely contacted with the protruding portion 18a and can be deformed according to the seal size, the first and second separators 14,
The airtightness of the sealed portion can be ensured only by sandwiching the fuel cell 12 with the fuel cell 16. That is, since the cross-sectional area of the liquid seal S can be increased in the groove portion 28 as compared with the case where the groove portion 28 is not provided, the amount of elastic deformation can be increased, and therefore, the margin for crushing can be sufficiently secured to improve the sealing performance. it can.

Then, the first and second separators 14 and 16
The liquid seal S absorbs the variation in the seal size between the liquid seal S and the protruding portion 18a of the solid polymer electrolyte membrane 18, thereby preventing the biased force from acting on the separators 14, 16. , 16 can be reduced in thickness, and the overall weight and size can be reduced. Therefore, the arrangement space is limited, and it is suitable for the case where the separators 14 and 16 are used for vehicles that need to be as thin as possible.

Further, in order to make the liquid seal S directly adhere to the solid polymer electrolyte membrane 18, the number of parts and the number of sets are compared with a case where a frame-like frame is provided around the fuel cell 12, for example. This is advantageous in that the number of attachment steps can be reduced.
Then, the liquid seal S for the solid polymer electrolyte membrane 18 is formed.
Is uniform, and the solid polymer electrolyte membrane 18 does not receive a biased force. As described above, even when the solid polymer electrolyte membrane 18 is wavy, the solid polymer electrolyte membrane 18 can be deformed in accordance with the wave, so that the solid polymer electrolyte membrane 18 does not wrinkle.

Further, the liquid seal S is inserted into the grooves 28, 30, 3
Liquid seal S to be applied to grooves 4 and 35
The cross-sectional area of the liquid seal S is enlarged, so that the fluctuation of the surface pressure with respect to the compression amount of the liquid seal S can be moderated. Therefore, the stress difference due to the variation of the interval between the liquid seals S can be reduced.

The present invention is not limited to the above embodiment. For example, as shown in FIG. 16, the fuel cell 10 of the type in which two sets of fuel cells 12 are sandwiched by three separators 15 is used. Can be applied.

[0040]

As described above, according to the first aspect of the present invention, the liquid seal that directly adheres to the protruding portion provided around the solid polymer electrolyte membrane is provided. The shape changes between the seal and the separator to follow the variation in the seal dimensions, and the airtightness between the two can be ensured by interposing without any gap between the two while maintaining a constant surface pressure in the groove. For this reason, a uniform sealing reaction force is obtained over the entire circumference between the separator and the electrode film structure, and there is an effect that uniform sealing properties can be secured. Therefore, due to the good responsiveness to the dimensional error due to the liquid seal, it is not necessary to strictly control the dimensions of the separator and the electrode film structure, and there is an effect that the dimensional accuracy can be easily controlled and the cost can be reduced.

According to the second aspect of the present invention, the liquid seal applied to the inside of the groove portion of the separator can sufficiently secure a crushing margin while maintaining a constant width in the groove portion, and can provide the solid polymer. The electrolyte membrane adheres to the protruding portion and can be deformed according to the conformable seal size, and then is heated and hardened, so assembling while securing the sealing performance only by sandwiching the electrode membrane structure with the separator There is an effect that can be.

According to the third aspect of the present invention, the unevenness of the seal size between the separator and the protruding portion of the solid polymer electrolyte membrane is absorbed by the liquid seal, so that a biased force acts on the separator. Therefore, the thickness of the separator can be reduced, and the overall weight and size of the separator can be reduced, which is suitable for a vehicle.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a view showing a first separator according to the embodiment of the present invention;
FIG.

FIG. 4 shows a second separator according to the embodiment of the present invention.
FIG.

FIG. 5 shows a second separator according to the embodiment of the present invention.
FIG.

FIG. 6 is an enlarged view of a main part of FIG. 2 of the embodiment of the present invention.

FIG. 7 is an explanatory diagram showing the relationship between the solid polymer electrolyte membrane and the liquid seal according to the embodiment of the present invention.

FIG. 8 is a conventional explanatory diagram corresponding to FIG. 7;

FIG. 9 is a diagram showing a manufacturing process according to the embodiment of the present invention.

FIG. 10 is a diagram showing a manufacturing process according to the embodiment of the present invention.

FIG. 11 is a diagram showing a manufacturing process according to the embodiment of the present invention.

FIG. 12 is a diagram showing a manufacturing process according to the embodiment of the present invention.

FIG. 13 is a diagram showing a manufacturing process according to the embodiment of the present invention.

FIG. 14 is a diagram illustrating a manufacturing process according to the embodiment of the present invention.

FIG. 15 is a diagram showing a manufacturing process according to the embodiment of the present invention.

FIG. 16 is a sectional view corresponding to FIG. 6 of another embodiment of the present invention.

FIG. 17 is a sectional view of a conventional technique.

[Explanation of symbols]

 12 Fuel Cell (Electrode Membrane Structure) 14 First Separator 16 Second Separator 18 Solid Polymer Electrolyte Membrane 18a Protruding Part 20 Cathode Electrode 22 Anode Electrode 24 First Gas Diffusion Layer 26 Second Gas Diffusion Layer 28 Groove S Liquid Seal

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshihiko Suenaga 1-4-1 Chuo, Wako-shi, Saitama Prefecture Inside Honda R & D Co., Ltd. (72) Harumi Hatano 1-4-1 Chuo, Wako-shi, Saitama F-term in Honda R & D Co., Ltd. (reference) 5H026 AA06 BB04 CC03 CC08 HH03

Claims (3)

[Claims] 1. A fuel cell comprising a solid polymer electrolyte membrane and an electrode membrane structure comprising an anode-side diffusion electrode and a cathode-side diffusion electrode on both sides thereof sandwiched between a pair of separators. Protruding portions protruding from the outer periphery of the anode-side diffusion electrode and the outer periphery of the cathode-side diffusion electrode are provided around the polymer electrolyte membrane, and at the outer peripheral portion in the separator surface, at a position corresponding to the protruding portion of the solid polymer electrolyte membrane. A fuel cell, wherein a groove is provided, and an electrode membrane structure is sandwiched between a pair of separators in a state where a liquid seal applied to the groove is in close contact with the protruding portion of the solid polymer electrolyte membrane. 2. A method for manufacturing a fuel cell, comprising an electrode membrane structure composed of a solid polymer electrolyte membrane and anode-side diffusion electrodes and cathode-side diffusion electrodes on both sides thereof sandwiched between a pair of separators. A liquid seal is applied to a groove formed in an outer peripheral portion of the separator surface, and the liquid seal before curing is provided around the solid polymer electrolyte membrane and protrudes from the periphery of the anode-side diffusion electrode and the cathode-side diffusion electrode. A method for manufacturing a fuel cell, comprising sandwiching an electrode membrane structure between a pair of separators in a state of being in close contact with a protruding portion, and thereafter heating and curing a liquid seal. 3. The fuel cell according to claim 1, wherein the fuel cell is for a vehicle.