JP2007080612A - Separator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a separator easy to manufacture and superior in sealing performance. <P>SOLUTION: In the separator 100 installed in a cell stack constituted by being overlapped with a plurality of unit cells, and wherein a first plate 110 and a second plate 120 at which recessed and projecting parts are formed in the front and the rear face are overlapped, and wherein the respective gaps formed between the plate and an anode, between the plate and a cathode, and between the plates are respectively used as a passage R1 of a fuel, a passage R2 of an oxidizer, and a passage R3 of a coolant by the recessed and projecting parts formed in the respective plates, a through hole 113 is installed at the first plate 110, a cylindrical part 123 fitted into the inner peripheral face of the through hole 113 is installed at the second plate 120, a pair of a first seal projecting part 131 and a second seal projecting part 132 respectively installed at the anode side and the cathode side, and a coupling part 133 to couple these via the through hole of the inner peripheral face side of the cylindrical part 123 are provided, and a gasket 130 to prevent leakage of the fuel, the oxidizer, and the coolant is equipped. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a separator provided in a cell stack in a fuel cell.

  Generally, a fuel cell (solid polymer fuel cell) has a configuration including 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 these are 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 reactive gas to each single cell, and a gas not used in the reaction. It plays the role of a gas manifold that discharges 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.

  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 superimposing two plates that have been subjected to uneven processing in this way (see Patent Documents 1 to 6).

  When a separator is formed by stacking two plates, a gasket for preventing fuel leakage and a gasket for preventing oxidant leakage are provided on both surfaces in the same manner as in the case of a separator composed of a single plate. In addition, a gasket must be provided between the two plates. Therefore, there are problems such as an increase in the number of steps for forming the gasket.

  As a technique for solving this problem, a technique is known in which a through-hole penetrating two stacked plates is provided and gaskets on both sides of the separator are connected through the through-hole (see Patent Document 7). The separator according to this conventional example will be described with reference to FIGS. FIG. 5 is a part of a schematic cross-sectional view of a separator according to a conventional example. FIG. 6 is a partially enlarged view of FIG. In addition, FIG. 6 is the figure which expanded the part in which the gasket is provided among FIG.

  As shown in the figure, the separator 500 according to this conventional example has a configuration in which a first plate 510 and a second plate 520 each having a concavo-convex process are overlapped. Thus, passages R1 and R2 are formed on both surfaces of the separator 500, and a passage R3 is also formed between the first plate 510 and the second plate 520. One of the passages R1, R2 is used as a fuel flow passage, and the other is used as an oxidant flow passage. The passage R3 is used as a coolant flow passage.

  Here, the first plate 510 and the second plate 520 are provided with through holes 511 and 512, respectively. These through holes 511 and 512 communicate with each other in a state where the first plate 510 and the second plate 520 are overlapped, and a through hole penetrating the separator 500 is formed. And a pair of seal convex parts 531 and 532 respectively provided on both surfaces of the separator 500 are connected through this through hole.

As described above, this conventional example includes the gasket 530 that integrally includes the pair of seal convex portions 531 and 532 provided on both surfaces of the separator 500. One of the seal projections 531 and 532 in the gasket 530 is used for preventing leakage of fuel, and the other is used for preventing leakage of oxidant. Further, the leakage of the coolant can be prevented by the portions connecting the seal convex portions 531 and 532.

  As described above, according to this conventional example, the leakage of fuel, oxidant, and coolant can be prevented with one gasket 530, so that there is an advantage that the process of forming the gasket can be reduced.

  However, in the conventional example configured as described above, when the gasket 530 is molded, the gasket 530 has a small gap S between the first plate 510 and the second plate 520 due to the pressure at the time of injection molding. Part of the material (rubber) may get in. A portion indicated by an arrow X in FIG. 6 is a portion where a part of the material has entered the minute gap S. Thus, if a part of the material enters the minute gap S, the sealing performance may be adversely affected.

  Further, in the conventional example configured as described above, the first plate 510 and the second plate 520 are positioned so that the through holes 511 and 512 provided in the first plate 510 and the second plate 520 respectively coincide with each other. In the combined state, the gasket 530 must be molded. However, when the gasket 530 is molded, a load such as pressure due to injection molding is applied to the first plate 510 and the second plate 520. Therefore, when the gasket 530 is molded, the first plate 510 and the second plate 520 are accurately positioned. There is also a problem that it is difficult to leave. Although it may be possible to fix the first plate 510 and the second plate 520 in advance using an adhesive or the like, even in that case, it is difficult to accurately position and fix both without a gap, There is a problem that the number of manufacturing processes increases. There is also a problem that it is difficult to prevent the adhesive from protruding from the gap between the first plate 510 and the second plate 520.

As described above, some problems remain in the case of the conventional example.
JP 2002-100381 A JP 2002-305006 A Japanese Patent Laid-Open No. 2003-177876 Japanese Patent Laid-Open No. 2004-7502 JP 2004-127711 A JP 2005-32577 A JP 2004-152745 A

  An object of the present invention is to provide a separator that is easy to manufacture and excellent in sealing performance.

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

That is, the separator of the present invention is
A separator provided in a cell stack configured by overlapping a plurality of single cells,
Two plates with irregularities formed on the front and back are superimposed,
Due to the irregularities formed in each plate, the gaps formed between the plate and the anode, between the plate and the cathode, and between the two plates are respectively a fuel flow path, an oxidant flow path, and In a separator used as a coolant flow path,
One of the two plates is provided with a through hole, and the other plate is provided with a cylindrical portion that fits into the inner peripheral surface of the through hole provided in one plate,
A pair of seal projections provided on the anode side and the cathode side, respectively, and a connecting portion for connecting these seal projections via a through hole on the inner peripheral surface side of the cylindrical portion; A gasket for preventing leakage of the coolant is provided.

  According to the present invention, the leakage of fuel, oxidant and coolant can be prevented by a single gasket, so that the number of steps for forming the gasket can be reduced. Moreover, since the cylindrical part provided in the other plate fits in the through-hole provided in one plate, both can be positioned easily. And since a pair of seal convex parts provided respectively on both surfaces (anode side and cathode side) of the separator are connected via a through hole on the inner peripheral surface side of the cylindrical part provided on the other plate, the plate Part of the gasket material does not get in between.

  Moreover, it is good for the edge part by the side of one plate in the said cylindrical part to provide the bending part which pinches | interposes the opening edge part of the through-hole provided in one plate.

  In this way, the two plates can be positioned and fixed in advance.

  As described above, according to the present invention, manufacturing is easy and the sealing performance is improved.

  The best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. .

  With reference to FIGS. 1-3, the separator which concerns on Example 1 of this invention is demonstrated. FIG. 1 is a schematic cross-sectional view of a fuel cell according to Embodiment 1 of the present invention. FIG. 2 is a plan view of the separator according to Example 1 of the present invention. FIG. 3 is a part of a cross-sectional view of the separator according to Example 1 of the present invention. 3 corresponds to the AA cross section in FIG.

<Fuel cell>
In particular, the configuration of the fuel cell will be described with reference to FIG. In FIG. 1, only a part of the single cell group among the fuel cells including a plurality of single cells is shown. As described above, the fuel cell (solid polymer fuel cell) includes a cell stack in which a plurality of single cells are stacked.

  First, a single cell will be described. The single cell has a configuration in which an electrolyte membrane is sandwiched between an anode and a cathode made of a catalyst layer and a gas diffusion layer. In this embodiment, the MEA 200 having the catalyst layer and the gas diffusion layer integrally provided on both surfaces of the electrolyte membrane is provided, and the catalyst layer and the gas diffusion layer provided on one surface of the electrolyte membrane function as an anode. The catalyst layer and the gas diffusion layer provided on the other surface function as a cathode. This MEA 200 is sandwiched between a pair of separators 100. A single cell is configured by the opposing surfaces of the MEA 200 and the pair of separators 100 sandwiching the MEA 200.

  In addition, when a fuel containing hydrogen is allowed to flow on the anode side of the single cell and an oxidizing agent containing oxygen is allowed to flow on the cathode side, a reaction occurs in the catalyst layer to generate power. That is, at the anode, hydrogen is divided into protons and electrons, and the protons move with water molecules through the membrane to the cathode, and the electrons move through the external circuit to the cathode. At the cathode, oxygen in the oxidant reacts with protons and electrons moving from the anode to generate water. In this way, current flows from the cathode side to the anode side.

  A cell stack 1 is configured by overlapping a plurality of single cells configured in this manner. That is, as shown in FIG. 1, separators 100 and MEAs 200 are alternately arranged, one of both surfaces of the MEA 200 is an anode 300, the other is a cathode 400, and the anode 300 and the cathode 400 are also provided alternately. Thereby, it will be in the state where the single cell was connected in series, and big electric power generation is obtained in the whole fuel cell.

<Separator>
In particular, the separator according to the present embodiment will be described in detail with reference to FIGS. The separator 100 according to the present embodiment includes a first metal plate 110, a second metal plate 120, and a rubber gasket 130. As shown in FIG. 3, the first plate 110 and the second plate 120 are overlapped to form the separator 100. In this embodiment, the case where the first plate 110 side is used as an anode and the second plate 120 side is used as a cathode will be described as an example.

  The 1st plate 110 is comprised from the thin metal plate, and the uneven | corrugated process (for example, press work) is given to the reaction area | region. As a result, the convex portion 111 protruding toward the MEA 200 abuts or approaches the MEA 200, and the concave portion 112 between the convex portions 111 is separated from the MEA 200. In particular, a gap is formed between the convex portion 112 and the MEA 200. . This gap forms a passage R1 through which fuel flows.

  FIG. 2 schematically shows a state in which one flow path that meanders so as to reach the entire reaction region is formed, but it is needless to say that the flow path does not need to be configured by one, and a plurality of flow paths are formed. This can be formed.

  Similarly, the second plate 120 is made of a thin metal plate, and a concavo-convex process (for example, press process) is applied to the reaction region. Thereby, the convex part 121 protruding to the MEA 200 side comes into contact with or close to the MEA 200, and the concave part 122 between the convex parts 121 is separated from the MEA 200, and in particular, a gap is formed between the MEA 200 and the concave part 122. . The gap forms a passage R2 through which the oxidant flows.

  A gap is also formed between the convex portion 111 of the first plate 110 and the convex portion 121 of the second plate 120. A passage R3 through which the coolant flows is formed by this gap.

  The first plate 110 is provided with a circular through hole 113. The second plate 120 is provided with a cylindrical portion 123 that fits into the inner peripheral surface of the through hole 113. In this manner, the first plate 110 and the second plate 120 are positioned by fitting the cylindrical portion 123 provided in the second plate 120 into the through hole 113 provided in the first plate 110. Note that the number of the through holes 113 and the cylindrical portion 123 may be appropriately set according to the shape and size of the plate. In order to position reliably, it is sufficient to provide at least two, and as shown in the figure, when the shape of the separator is a rectangle, it is preferable to provide at least one on each side.

  Thus, the gasket 130 is formed by molding in a state where the first plate 110 and the second plate 120 are positioned. The gasket 130 includes a first seal convex portion 131 provided on the first plate 110 side, a second seal convex portion 132 provided on the second plate 120 side, and a connecting portion 133 that connects them. The first seal convex portion 131, the second seal convex portion 132, and the connecting portion 133 are integrally configured by integral molding.

  The first seal convex portion 131 is provided so as to surround a region of the first plate 110 that has been subjected to uneven processing, and exhibits a function of preventing fuel leakage. Moreover, the 2nd seal convex part 132 is provided so that the area | region where the uneven | corrugated process was performed in the 2nd plate 120 may be enclosed, and the function which prevents the leakage of an oxidizing agent is exhibited.

  The connecting portion 133 is configured to connect the first seal convex portion 131 and the second seal convex portion 132 through a through hole on the inner peripheral surface side of the cylindrical portion 123 provided in the second plate 120. The The function of preventing leakage of the coolant is exhibited by the vicinity of the connecting portion 133.

<Excellent points of this embodiment>
According to the separator 100 according to the present embodiment, the connecting portion 133 is connected to the first seal convex portion 131 and the second seal convex portion through the through hole on the inner peripheral surface side of the cylindrical portion 123 provided in the second plate 120. Since the portion 132 is connected, it is possible to prevent a part of the material from entering the gap between the first plate 110 and the second plate 120 due to the injection molding pressure when the gasket 130 is molded. . Thereby, it can prevent that the 1st plate 110 and the 2nd plate 120 peel, and can exhibit the stable sealing performance.

  Further, by fitting the cylindrical portion 123 provided on the second plate 120 into the through hole 113 provided on the first plate 110, the first plate 110 and the second plate 120 can be easily connected without using an adhesive or the like. Can be positioned. In addition, since the cylindrical portion 123 is fitted in the inner peripheral surface of the through hole 113, the first plate 110 and the second plate 120 are prevented from being displaced even when an injection molding pressure is applied during the molding of the gasket 130. can do. In addition, by providing two or more sets of the through-holes 113 and the cylindrical portions 123, displacement in the rotation direction of the first plate 110 and the second plate 120 is prevented, so that these displacements can be prevented more reliably. . However, instead of the cylindrical portion 123, if the planar shape is a cylindrical portion having a shape other than a circle (for example, an ellipse, a square, or a star shape), and the shape of the through hole 113 is also a shape that conforms to the cylindrical portion, there is only one. However, a shift in the rotational direction can be prevented.

  Furthermore, according to the present embodiment, the leakage of fuel, oxidant and coolant can be prevented by the single gasket 130, so that it is not necessary to form dedicated gaskets, and the number of steps for forming the gaskets can be reduced. .

  As described above, the number of steps for forming the gasket is small, and the first plate 110 and the second plate 120 can be easily positioned. Therefore, the separator 100 can be easily manufactured.

<Others>
In this embodiment, the case where the first plate 110 side is used as an anode and the second plate 120 side is used as a cathode is shown, but the first plate 110 side may be used as a cathode and the second plate 120 side may be used as an anode. In this case, it goes without saying that the oxidizing agent flows in the passage R1 and the fuel flows in the passage R2.

In the present embodiment, a configuration in which the cylindrical portion 123 is provided in the second plate 120 and the circular through hole 113 is provided in the first plate 110 corresponding to the cylindrical portion 123 is shown. Is not limited to these.

  A configuration for sending reaction gas (fuel and oxidant) and coolant to each single cell, and for discharging reaction gas after reaction and water or coolant generated by the reaction from each single cell (manifold etc.) Since a publicly-known technique can be applied as appropriate, the description thereof is omitted in this embodiment.

  FIG. 4 shows a second embodiment of the present invention. In the present embodiment, a modification of the cylindrical portion provided in the second separator in the first embodiment will be described. Since other configurations and operations are the same as those in the first embodiment, the same components are denoted by the same reference numerals and description thereof is omitted. FIG. 4 is a part of a sectional view of a separator according to Example 2 of the present invention.

  As illustrated, in the separator 100a according to the present embodiment, the opening of the through hole 113 provided in the first plate 110 is provided at the end of the cylindrical portion 123a provided in the second plate 120a on the first plate 110 side. A bent portion 124 that sandwiches the end portion is provided.

  The bent portion 124 can be formed by providing a long cylindrical portion provided on the second plate 120a and caulking the end portion thereof by press working or the like.

  According to the present embodiment, the same effect as in the first embodiment can be obtained, and the first plate 110 and the second plate 120a can be positioned only by sandwiching the opening end portion of the through hole 113 by the bent portion 124. But can be fixed. Therefore, when the gasket 130 is molded, the first plate 110 and the second plate 120a are easily handled as compared to the case of the first embodiment, and the displacement of these during injection molding is more reliably prevented. It becomes possible to do.

FIG. 1 is a schematic cross-sectional view of a fuel cell according to Embodiment 1 of the present invention. FIG. 2 is a plan view of the separator according to Example 1 of the present invention. FIG. 3 is a part of a cross-sectional view of the separator according to Example 1 of the present invention. FIG. 4 is a part of a sectional view of a separator according to Example 2 of the present invention. FIG. 5 is a part of a schematic cross-sectional view of a separator according to a conventional example. FIG. 6 is a partially enlarged view of FIG.

Explanation of symbols

1 Cell stack 100, 100a Separator 110 First plate 111 Convex part 112 Concave part 113 Through hole 120, 120a Second plate 121 Convex part 122 Concave part 123, 123a Cylindrical part 124 Bending part 130 Gasket 131 First seal convex part 132 Second seal Convex part 133 connecting part 200 MEA
300 Anode 400 Cathode R1, R2, R3 passage

Claims (2)

A separator provided in a cell stack configured by overlapping a plurality of single cells,
Two plates with irregularities formed on the front and back are superimposed,
Due to the irregularities formed in each plate, the gaps formed between the plate and the anode, between the plate and the cathode, and between the two plates are respectively a fuel flow path, an oxidant flow path, and In a separator used as a coolant flow path,
One of the two plates is provided with a through hole, and the other plate is provided with a cylindrical portion that fits into the inner peripheral surface of the through hole provided in one plate,
A pair of seal projections provided on the anode side and the cathode side, respectively, and a connecting portion for connecting these seal projections via a through hole on the inner peripheral surface side of the cylindrical portion; A separator comprising a gasket for preventing leakage of a coolant.   2. The separator according to claim 1, wherein a bent portion that sandwiches an opening end portion of a through hole provided in one plate is provided at an end portion on one plate side of the cylindrical portion.

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