JP4968505B2 - Fuel cell separator - Google Patents

Description

  The present invention relates to a fuel cell separator.

Conventionally, a fuel cell is configured to include a cell stack in which a plurality of single cells are stacked.
Here, the single cell has a configuration in which an electrolyte membrane is sandwiched between an anode and a cathode including a catalyst layer and a gas diffusion layer, and this is sandwiched between a pair of separators.
Here, the separator plays a role of forming a fuel flow path and an oxidant flow path, a role of separating the fuel and the oxidant, supplying a reaction gas to each single cell, and a gas not used in the reaction. It plays the role of a gas manifold that discharges from a single cell, the role of flowing a coolant to remove reaction heat, and the role of a seal to prevent the reaction gas from leaking outside the battery.

As the separator, a plate-like material made of carbon or metal is generally used.
In the case of a metal plate, uneven processing is generally performed in the vicinity of the reaction region, and a flow path for fuel and oxidant is generally formed by the uneven portion.
In addition, a technique is also known in which a gap formed between two plates is used as a coolant flow path by stacking two plates having such irregularities (Japanese Patent Laid-Open No. 2002-305006).

  When a separator is formed by stacking two plates of this type, not only a fuel leakage prevention gasket and an oxidant leakage prevention gasket are provided on both sides in the same manner as in the case of a separator composed of a single plate. A gasket must also be provided between the two plates.

For this reason, there is a problem that the number of steps for forming the gasket increases.
As a technique for solving this problem, a structure shown in FIG. 4 is known (Japanese Patent Laid-Open No. 2004-152745).
That is, a technique is known in which a communication hole 140 is provided that penetrates the two overlapped plates 100 and 200 and the gaskets on both sides of the separator are communicated with each other through the communication hole 140.

However, the communication hole 140 exists only in a limited part on the plate. as a result,
There was a risk of coolant (water) leaking from between the mating surfaces of the two plates 100 and 200 where the communication hole 140 does not exist. That is, the coolant A does not leak to the right side in the figure at a place where the communication hole 140 is filled with the rubber-like elastic sealing element 400, but at a place where the communication hole 140 does not exist, the seal element 400 does not leak. Since it did not exist, leakage of the coolant could not be prevented reliably.

In particular, it was remarkable when foreign matter was present between the mating surfaces of the two plates 100 and 200, or when the surface of the plates 100 and 200 had irregularities or a surface roughness greater than a certain level.
In such a case, an adhesive, sealant, double-sided adhesive tape, etc. can be interposed between the mating surfaces of the two plates 100, 200 to reliably prevent leakage of the coolant, but the manufacturing cost increases. However, it has a problem that the work is complicated.

As described above, some problems remain in the case of the conventional example.
JP 2002-305006 A JP 2004-152745 A

An object of the present invention is to provide a fuel cell separator that is easy to manufacture and excellent in sealing performance.
Another object of the present invention is to provide a fuel cell separator capable of exhibiting a stable sealing performance for a long period of time by constantly keeping the seal surface pressure generated in the seal element constant.
Still another object of the present invention is to provide a fuel cell separator capable of exhibiting more stable sealing performance by adopting an embodiment in which the electrolyte membrane is pressed through a frame.

  The present invention employs the following means in order to solve the above problems.

  That is, the fuel cell separator according to the present invention is a fuel cell separator that is arranged in a large number of stacked layers, and two metal plates having concavities and convexities formed on the front and back are overlapped symmetrically, and the peripheral portion thereof. In the fuel cell separator in which the sealing elements are formed on both sides by the sealing member made of an elastic material, the sealing elements are formed in both concave portions of the portion where the convex portions of the metal plate overlap, and on both sides of the sealing elements. An inner space and an outer space are formed by the two recesses between the two metal plates, and at least one of the two spaces is filled with the elastic seal member. A closed region is formed, and the closed region and the sealing element communicate with each other through a communication hole provided in the metal plate.

  Further, when the closed region is provided in both the spaces between which the sealing element is sandwiched, the sealing performance is further improved.

  Furthermore, when the top portions of the two metal plates forming the two voids are on the same plane and the sealing element protrudes from the plane, a stable sealing performance for a long period of time can be obtained. Can be maintained.

  Furthermore, an elastic material frame is provided on the electrolyte membrane sandwiched between the separators, and the electrolyte membrane forms the sealing element and the two voids via the frame. By adopting an aspect in which the plate is sandwiched between the tops of the plates, a stable sealing performance can be maintained for a long time without damaging the electrolyte membrane.

  In addition, when the elastic sealing member is formed using liquid rubber, it is easy to mold, and the sealing element can be reliably filled into the target location through the communication hole, so that reliable sealing can be achieved. .

The present invention has the following effects.
According to the fuel cell separator of the first aspect of the present invention, the coolant does not leak out from the mating surfaces of the two metal plates, and the surface of at least one of the two members in contact with the seal ring is uneven, An object of the present invention is to provide a fuel cell separator that does not impair the sealing performance even if there is a scratch.

  According to the fuel cell separator of the second aspect of the present invention, it is an object to provide a fuel cell separator capable of maintaining a stable sealing performance for a long period of time.

  Furthermore, according to the fuel cell separator of the third aspect of the invention, it is an object to provide a fuel cell separator capable of ensuring good sealing performance on the contact surface.

  Still another object of the present invention is to provide a fuel cell separator that can maintain stable sealing performance for a long period of time without damaging the electrolyte membrane.

  In addition, according to the fuel cell separator of the fifth aspect of the present invention, the fuel cell can be reliably sealed because it can be easily molded and the sealing element can be reliably filled into the target portion through the communication hole. An object of the present invention is to provide a separator.

Hereinafter, the best mode for carrying out the present invention will be described.
The best mode for carrying out the invention will be described with reference to FIG.
The fuel cell is configured to include a cell stack in which a plurality of single cells are stacked.
Here, the single cell has a configuration in which an electrolyte membrane is sandwiched between an anode and a cathode including a catalyst layer and a gas diffusion layer, and further, is sandwiched between a pair of fuel cell separators.
Here, the separator for the fuel cell has a role of forming a fuel flow path and an oxidant flow path, a role of separating the fuel and the oxidant, a reaction gas being supplied to each single cell, or not used for the reaction. It plays the role of a gas manifold that discharges gas from each single cell, the role of flowing a coolant to remove reaction heat, and the role of a seal to prevent the reaction gas from leaking outside the battery.

A separator for a fuel cell that is arranged in a large number of stacked layers, and two metal plates 1 and 2 having concavities and convexities formed on the front and back are superimposed in line symmetry.
And the sealing element 4 and 5 are formed in the both surfaces by the sealing member 3 made from an elastic material in the peripheral part.
As the material of the elastic seal member 3 used here, nitrile rubber, EPDM, urethane rubber, silicone rubber, fluorine rubber, or the like is appropriately selected according to the intended use. In particular, these liquid rubbers are preferable.
The convex parts 6 and 7 of the metal plates 1 and 2 are overlapped, and the sealing elements 4 and 5 are formed in the concave parts 8 and 9 formed on the upper and lower surfaces.

The sealing elements 4 and 5 are connected and integrated with each other by a communication hole 14 in which the convex portions 6 and 7 of the metal plates 1 and 2 are provided so as to penetrate through the portions in contact with each other.
An inner space 10 and an outer space 11 are formed by the concave portions 8 and 9 between the two metal plates 1 and 2 existing on both sides of the sealing elements 4 and 5.
Both voids 10 and 11 are filled with an elastic seal member 3 to form closed regions 12 and 13.

The closed regions 12 and 13 communicate with each other through communication holes 14, 14, 14, and 14 provided on the inclined surfaces (side surfaces) of the metal plates 1 and 2.
Therefore, the sealing elements 4, 5 and the closed regions 12, 13 provided on the upper and lower surfaces communicate with each other through the communication holes 14, 14, 14, 14.
In the present embodiment, the communication holes 14 are provided in the portions where the convex portions 6 and 7 of the two metal plates 1 and 2 are in contact with each other, but the communication holes 14 are provided in the inclined surfaces (side surfaces) of the two metal plates 1 and 2. , 14, 14, and 14 may be configured such that both seal elements 4 and 5 communicate with each other.
That is, the elastic seal member 3 injected from the seal element 4 side fills the closed regions 12 and 13 and then exits from the communication holes 14 and 14 provided on the inclined surfaces (side surfaces) to form the seal element 5. It is good also as a form to do.

In this embodiment, both the inner space 10 and the outer space 11 are filled with the elastic seal member 3 and the closed regions 12 and 13 are provided on both sides. Although leakage can be prevented more reliably, the effect of preventing leakage of the coolant can be obtained even if the closed regions 12 and 13 are provided only in one of the inner space 10 and the outer space 11.
The top portions 15 and 15 of the two metal plates 1 and 2 forming both the voids 10 and 11 are on the same plane, and the sealing elements 4 and 5 are projected from the plane.
The seal elements 4 and 5 sandwich the electrolyte membrane, thereby preventing the leakage of fuel and oxidant.

The cross-sectional shape of the seal elements 4 and 5 projecting from the plane has a semicircular shape, but is not limited to this shape, and as shown in the embodiment shown in FIG. It is good also as an aspect which provides a dent on both surfaces of the 4 and 5 convex part.
Thus, when it is set as the aspect which provides a hollow, since the escape part of the sealing elements 4 and 5 exists, there exists an advantage which can suppress a sealing surface pressure low.

And the separator for fuel cells comprised in this way is laminated | stacked in the form shown in FIG.
That is, the electrolyte membrane 16 is sandwiched between the seal elements 4 and 5 of the separators 0 and 0.
The MEA 18 in which the electrolyte membrane 16 is sandwiched between the anode and the cathode formed of the catalyst layer and the gas diffusion layer is sandwiched between the top portions 15 and 15 of both the metal plates 1 and 2.
As a result, the electrolyte membrane 16 is not excessively pressed by the seal elements 4 and 5, and the optimum seal surface pressure can always be maintained.

Further, another embodiment shown in FIG. 3 will be described.
The difference from the embodiment shown in FIG. 2 is that an elastic material frame 17 is provided, and the electrolyte membrane 16 forms the sealing elements 4 and 5 and the two spaces 10 and 11 via the frame 17. The point is that the metal plates 1 and 2 are sandwiched between the top portions 15 and 15 of the metal plates 1 and 2.
As a result, the electrolyte membrane 16 can be reliably prevented from being damaged, and the seal at this point can be made more reliable.
The frame 17 is formed integrally or separately from rubber or resin.

  Further, the present invention is not limited to the best mode for carrying out the invention described above, and various other configurations can be adopted without departing from the gist of the present invention.

It is a half sectional view showing an embodiment of the invention concerning the separator for fuel cells. FIG. 2 is a half sectional view showing a single cell in which two fuel cell separators of FIG. 1 are assembled. It is a half section showing a single cell of other embodiments concerning a separator for fuel cells. It is a half sectional view showing the prior art concerning the separator for fuel cells.

Explanation of symbols

1, 2 ... Metal plate 3 ... Seal member 4 made of elastic material, 5 ... Seal elements 6, 7 ... Convex part 8, 9 ... Concave part 10 ... Inner cavity 11 ... Outer cavity 12 , 13 Closed region 14 Communication hole 15 Top 16 Electrolyte membrane 17 Frame 18 MEA

Claims (5)

  A separator for a fuel cell arranged in a large number of stacked layers, wherein two metal plates (1) and (2) having concavities and convexities formed on the front and back are overlapped symmetrically, and an elastic seal is formed at the peripheral edge In the fuel cell separator in which the sealing elements (4) and (5) are formed on both surfaces by the member (3), both of the overlapping portions of the convex portions (6) and (7) of the metal plates (1) and (2) are provided. The sealing elements (4) and (5) are formed in the recesses (8) and (9), and the two metal plates (1) and (2) existing on both sides of the sealing elements (4) and (5) An inner space (10) and an outer space (11) are formed by both concave portions (8) (9), and at least one of the voids (10) (11) (10) ( 11) is filled with the sealing member (3) made of the elastic material, and the closed region (1 ) (13) is formed, and the closed region (12) (13) and the sealing element (4) (5) communicate with each other through a communication hole (14) provided in the metal plate (1) (2). A separator for a fuel cell, characterized in that it is configured. The fuel cell separator according to claim 1, wherein the closed region (12) (13) is provided in the two spaces (10) (11) sandwiching the sealing element (4) (5). The top portions (15) and (15) of the two metal plates (1) and (2) forming the two voids (10) and (11) are respectively on the same plane, and the sealing element (4) ( The fuel cell separator according to claim 1 or 2, wherein 5) protrudes from the plane. An elastic material frame (17) is provided on the electrolyte membrane (16) sandwiched between the separators (0) and (0), and the electrolyte membrane (16) is interposed between the sealing element (4) and the frame (17). ) (5) and the top portions (15) (15) of the two metal plates (1) (2) forming the two spaces (10) (11). The fuel cell separator according to any one of claims 1 to 3 . The fuel cell separator according to any one of claims 1 to 4, wherein the elastic material sealing member (3) is formed using liquid rubber.

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