JP2009224275A - Separator for fuel cell, its manufacturing method, and fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology capable of easily positioning a passage formation section of an intermediate member. <P>SOLUTION: In a separator 30 for a fuel cell, the separator 30 comprises the intermediate member 500, and first and second plates 400, 300 for sandwiching the intermediate member. The intermediate member 500 has a plurality of passage formation sections 570 arranged to separate each other, and the first plate 400 has a plurality of positioning sections for positioning the plurality of passage formation sections 570 at the time of assembling the separator 30. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel cell, and more particularly to a fuel cell separator.

  As a structure of a conventional fuel cell, for example, a fuel cell described in Patent Document 1 is known. In this fuel cell, a set of separators is constituted by three plates. A coolant channel is formed in the intermediate plate.

JP 2007-109425 A

  However, depending on the shape of the intermediate plate, there may arise a problem that it is difficult to position the members forming the refrigerant flow path. Such a problem is common to separators having a configuration in which an intermediate member is sandwiched between two plates.

  An object of the present invention is to solve at least a part of the above-described problems and provide a technique that facilitates positioning of a flow path forming portion of an intermediate member.

  In order to solve at least a part of the above problems, the present invention takes the following aspects.

  The first aspect of the present invention is a fuel cell separator. The separator includes an intermediate member and first and second plates that sandwich the intermediate member from both sides, and the intermediate member includes a plurality of flow path forming portions that are spaced apart from each other. The plate includes a plurality of positioning portions that position the plurality of flow path forming portions when the separator is assembled. According to this aspect, since the flow path forming portion is positioned by the positioning portion, the flow path forming portion can be easily positioned.

  1st aspect of this invention WHEREIN: The convex part protruded to the said intermediate member side may be sufficient as the said positioning part. According to this aspect, the flow path forming part can be positioned by the convex part.

  1st aspect of this invention WHEREIN: The said flow-path formation part may have a recessed part engaged with the said convex part. According to this aspect, since the convex part and the concave part of the flow path forming part are engaged, the flow path forming part can be easily positioned.

  1st aspect of this invention WHEREIN: The said flow-path formation part is formed in the shape connected with the outer edge part of the said intermediate member before the said separator formation, The said intermediate member, the said 1st and 2nd plate, It may have a structure separated from the outer edge portion and separated after the joining. According to this aspect, the refrigerant flow path forming portion can be easily aligned as compared with the case where the flow path forming portion is not connected to the outer edge of the intermediate member.

  In the first aspect of the present invention, the intermediate member may be formed of a thermoplastic resin, and may be joined to the first and second plates by thermal welding. According to this aspect, since the intermediate member is thermally welded to the first plate and the second plate, the flow path forming portion is not easily displaced.

  In the first aspect of the present invention, a refrigerant flow path is formed between the first and second plates, and a part of the refrigerant flow path has a convex portion formed on the first plate. It may be formed using. According to this aspect, the coolant channel can be easily formed.

  The second aspect of the present invention is a fuel cell. The fuel cell includes the fuel cell separator according to the first aspect of the present invention. According to this aspect, the durability of the fuel cell can be improved and the manufacturing cost of the fuel cell can be reduced.

  A third aspect of the present invention is a method for manufacturing a fuel cell separator. The method for manufacturing a fuel cell separator includes: (a) preparing an intermediate member having a plurality of flow path forming portions and an outer edge portion formed integrally with the plurality of flow path forming portions; (b) A step of preparing a first plate having a plurality of positioning portions and a second plate used for positioning the plurality of flow path forming portions; and (c) the plurality of flow streams using the plurality of positioning portions. A step of sandwiching the intermediate member between the first and second plates while positioning the path forming portion; (d) a step of joining the first and second plates and the intermediate member; e) separating the plurality of flow path forming portions from the outer edge portion and separating the plurality of flow path forming portions from each other. According to this aspect, the fuel cell separator can be easily manufactured.

  The present invention can be realized in various forms, such as a fuel cell separator, a fuel cell, a fuel cell separator manufacturing method, a fuel cell manufacturing method, and the like. can do.

  FIG. 1 is a perspective view showing the appearance of the fuel cell according to the present embodiment. The fuel cell 100 includes a power generator 200 and end plates 202 and 204. In the present embodiment, a plurality of power generation bodies 200 are stacked, but the number of power generation bodies 200 may be one. The power generator 200 is also referred to as a “battery unit”. The end plates 202 and 204 are respectively disposed at both ends of the power generation body 200 in the stacking direction. In the fuel cell 100, a fuel gas supply manifold 110, a fuel gas discharge manifold 120, an oxidizing gas supply manifold 130, and an oxidizing gas discharge for supplying or discharging fuel gas, oxidizing gas, and refrigerant to and from the power generator 200. The manifold 140, the refrigerant supply manifold 150, and the refrigerant discharge manifold 160 pass through in the stacking direction.

  2 is a cross-sectional view of the fuel cell 100 taken along the line 2-2 shown in FIG. The power generation body 200 includes a membrane electrode assembly 210, an anode side gas diffusion layer 220, a cathode side gas diffusion layer 230, an anode side porous body layer 240, a cathode side porous body layer 250, a seal gasket 260, a separator. 30.

  The membrane electrode assembly 210 includes an electrolyte membrane and a catalyst layer disposed on both sides of the electrolyte membrane. In this embodiment, as the electrolyte membrane, for example, a proton conductive ion exchange membrane made of a fluorine resin such as perfluorocarbon sulfonic acid polymer or a hydrocarbon resin is used. Further, as the catalyst layer, for example, a catalyst layer in which a platinum catalyst or a platinum alloy catalyst made of platinum and another metal is supported on, for example, carbon particles is used.

  The anode side gas diffusion layer 220 and the cathode side gas diffusion layer 230 are disposed on both surfaces of the membrane electrode assembly 210, respectively. In this embodiment, carbon cloth or carbon paper using a carbon nonwoven fabric is used as the anode side gas diffusion layer 220 and the cathode side gas diffusion layer 230. The anode side porous body layer 240 and the cathode side porous body layer 250 are arranged on the outer surfaces of the anode side gas diffusion layer 220 and the cathode side gas diffusion layer 230, respectively. In this embodiment, as the anode side porous body layer 240 and the cathode side porous body layer 250, for example, a porous body made of metal such as titanium or stainless steel is used. The anode-side porous layer 240 and the cathode-side porous layer 250 are not made of titanium or stainless steel, but may be made of other metal materials or other materials than metals as long as they have conductivity and corrosion resistance. May be.

  The seal gasket 260 is formed so as to surround the outer edges of the membrane electrode assembly 210, the anode side gas diffusion layer 220, the cathode side gas diffusion layer 230, the anode side porous body layer 240, and the cathode side porous body layer 250. The seal gasket 260 is integrally formed with the anode side gas diffusion layer 220, the cathode side gas diffusion layer 230, the anode side porous body layer 240, and the cathode side porous body layer 250, for example, by injection molding.

  The separator 30 includes a cathode plate 300, an anode plate 400, and an intermediate film 500. The cathode plate 300 is disposed outside the cathode-side porous layer 250, the intermediate film 500 is disposed outside the cathode plate 300, and the anode plate 400 is disposed outside the intermediate film 500.

  FIG. 3 is a plan view of the cathode plate 300. The cathode plate 300 is, for example, a substantially rectangular plate-shaped member made of metal. Various openings 310 to 360 are formed on the outer edge of the short side of the cathode plate 300. These openings 310 to 360 have the fuel gas supply manifold 110, the fuel gas discharge manifold 120, the oxidizing gas supply manifold 130, the oxidizing gas discharge manifold 140, the refrigerant supply manifold 150, and the refrigerant discharge manifold shown in FIG. 160 is an opening. In addition, elongated openings 332 and 342 are formed at the outer edge of the long side of the cathode plate 300. These openings 332 and 342 are used to supply an oxidizing gas to the cathode-side porous body layer 250 and exhaust the oxidizing gas from the cathode-side porous body layer 250. The openings 310 to 360, 332, and 342 are formed by punching, for example.

  FIG. 4 is a plan view of the anode plate 400. The anode plate 400 is a substantially rectangular plate-shaped member made of metal, for example. Openings 410 to 460 for forming various manifolds are formed at the outer edge of the short side of the anode plate 400. The positions and sizes of the openings 410 to 460 correspond to the positions and sizes of the openings 310 to 360 of the cathode plate, respectively. Elongated openings 412 and 422 are formed at the outer edge of the long side of the anode plate 400. These openings 412 and 422 are used for supplying the fuel gas to the anode-side porous layer 240 and discharging the fuel gas from the anode-side porous layer 240. The openings 410 to 460, 412, and 422 are formed by punching, for example. A plurality of convex portions 480 and 490 are formed at the central portion of the anode plate 400. The 1st convex part 480 is used in order to position the flow-path formation part 570 mentioned later. The second protrusions 490 are formed in a plurality of rows along the direction in which the refrigerant flows, and are used to form a refrigerant flow path at the center of the separator 30. The convex portions 480 and 490 are formed by, for example, pressing. In this embodiment, the convex portions 490 are arranged uniformly, but may be arranged unevenly. As shown in FIG. 2, the convex portion 490 is in contact with the cathode plate 300. Thereby, the cathode plate 300 and the anode plate 400 are electrically connected.

  FIG. 5 is a plan view of the intermediate film 500 after the separator 30 is formed. FIG. 6 is a plan view of the intermediate film 500 before the separator 30 is formed. The intermediate film 500 is, for example, a thermoplastic resinous substantially rectangular plate-like member. As shown in FIG. 2, the intermediate film 500 serves to bond the cathode plate 300 and the anode plate 400. As shown in FIG. 6, openings 510 to 560 for forming various manifolds are formed on the outer edge of the short side of the intermediate film 500, and an opening 555 serving as a space through which a refrigerant flows is formed in the center. Is formed. The openings 510 to 560 and the opening 555 are formed by punching.

  The positions and sizes of the openings 510 to 540 forming the gas manifold correspond to the positions and sizes of the openings 310 to 340 of the cathode plate 300, respectively. Note that the communication paths 512 and 522 extend from the openings 510 and 520 along the long side direction, and the communication paths 532 and 542 extend from the openings 530 and 540 along the long side direction. After the separator 30 is formed, the communication paths 512 and 522 communicate with the openings 412 and 422 of the anode plate 400, and the communication paths 532 and 542 communicate with the openings 332 and 342 of the cathode plate 300.

  As shown in FIG. 6, on the left and right sides of the intermediate film 500 before bonding, a plurality of flow path forming portions 570 arranged in a comb shape, and a connection for connecting these flow path forming portions 570 to the outer edge portion of the intermediate film 500 A portion 585 (also referred to as “base portion 585”) is formed. A recess 580 is provided in the vicinity of the tip of each flow path forming portion 570. The concave portion 580 engages with the convex portion 480 (FIG. 4) of the anode plate 400 during assembly of the separator, and thereby the flow path forming portion 570 is positioned. The base portion 585 is provided at a position that can be seen from the opening 350 (FIG. 3) of the cathode plate 300 and the opening 450 (FIG. 4) of the anode plate 400 when the separator is assembled. These root portions 585 are deleted after the separators are joined, and the plurality of flow path forming portions 570 are separated from each other as shown in FIG.

  The flow of reaction gas and refrigerant in the fuel cell will be briefly described. In this embodiment, hydrogen is used as the fuel gas and air is used as the oxidizing gas. The fuel gas is supplied from, for example, a fuel tank (not shown) to the fuel gas supply manifold 110 (FIG. 1). The fuel gas is supplied from the opening 510 (FIG. 5) forming the fuel gas supply manifold 110 to the anode-side porous body layer 240 (FIG. 2) through the communication portion 512 and the opening 412 (FIG. 4). The fuel gas reaches the membrane electrode assembly 210 while diffusing through the anode-side porous layer 240 and the anode-side gas diffusion layer 220, and is used for the electrochemical reaction of the fuel cell. Unreacted fuel gas is exhausted from the anode side gas diffusion layer 220 and the anode side porous body layer 240 to the outside of the fuel cell 100 through the opening 422, the communication part 522, the opening 520, and the fuel gas discharge manifold 120. The The oxidizing gas is supplied from the air intake (not shown) to the oxidizing gas supply manifold 130 through the compression pump (not shown). The oxidizing gas is supplied from the opening 530 that forms the oxidizing gas supply manifold 130 to the cathode-side porous body layer 250 through the communication portion 532 and the opening 332. The oxidizing gas reaches the membrane electrode assembly 210 while diffusing through the cathode side porous layer 250 and the cathode side gas diffusion layer 230, and is used for the electrochemical reaction of the fuel cell. Unreacted oxidizing gas is exhausted from the cathode side gas diffusion layer 230 and the cathode side porous body layer 250 to the outside of the fuel cell 100 through the opening 342, the communication part 542, the opening 540, and the oxidizing gas discharge manifold 140. The The refrigerant is supplied to the refrigerant supply manifold 150 from a refrigerant supply unit (not shown). The refrigerant is supplied from the opening 550 forming the refrigerant supply manifold 150 to the opening 555 through the flow path 575 formed between the adjacent flow path forming sections 570, and cools the fuel cell 100. The refrigerant passes through the opening 555, the flow path 575, the opening 560, and the refrigerant discharge manifold 160, and is discharged to the outside of the fuel cell 100.

  FIG. 7 is a flowchart showing the manufacturing process of the separator 30. First, the intermediate film 500 is disposed on the anode plate 400 (step S700). At this time, the projections 480 and 490 of the anode plate 400 are placed on the upper side, and the intermediate film 500 is placed on the projections 480 and 490 side.

  FIG. 8 is a plan view when the intermediate film 500 is disposed on the anode plate 400. Here, a state where a part of the anode plate 400 under the intermediate film 500 is visible through the opening of the intermediate film 500 is shown. In this state, the convex portion 480 of the anode plate 400 and the concave portion 580 of the flow path forming portion 570 are fitted. (Step S710). Here, when the anode plate 400 does not have the convex portion 480 and the flow path forming portion 570 does not have the concave portion 580, the position of the flow path forming portion 570 on the opening 555 side is as shown in FIG. 9 as a comparative example. May be disturbed. As a result, the intervals between the flow path forming portions 570 may be nonuniform, or the adjacent flow path forming portions 570 may overlap. As a result, the flow of the refrigerant is biased and the fuel cell cannot be cooled uniformly. In addition, when the convex portion 480 of the anode plate and the flow passage forming portion 570 are not provided with the concave portion 580 as in the comparative example, it is excessively troublesome to arrange the opening portion 555 side of the flow passage forming portion 570 without disturbance. There is a risk of increasing the manufacturing cost. In this embodiment, since the convex portion 480 is provided on the anode plate 400 and the concave portion 580 is provided on the flow path forming portion 570, the flow path forming portion 570 can be easily aligned. In addition, since the alignment of the flow path forming part 570 can be performed with high accuracy, a local temperature rise of the fuel cell can be prevented and its durability can be improved. Moreover, since the flow path forming part 570 is integrated with the intermediate film 500 before the separator 30 is joined, it is not necessary to prepare the flow path forming part 570 separately.

  After the alignment of the intermediate film 500 is thus completed, the cathode plate 300 is disposed on the intermediate film 500 (step S720). Then, the anode plate 400 and the cathode plate 300 are bonded with the intermediate film 500 (step S730). Specifically, pressure is applied from both sides of the anode plate 400 and the cathode plate 300 while heating. Thereby, the intermediate film 500 made of thermoplastic resin is melted, and the anode plate 400 and the cathode plate 300 are thermocompression bonded. Thereafter, the base portion 585 of the intermediate film 500 is cut (step S740). For example, the base portion 585 can be removed by cutting the cathode plate 300 through the openings 350 and 360 of the cathode plate 300. As a result, the flow path forming part 570 is separated from the intermediate film 500 and the adjacent flow path forming part 570 as shown in FIG. In addition, after the intermediate film 500 is bonded to the anode plate 400 and the cathode plate 300, the flow path forming portion 570 is bonded to the anode plate 400 and the cathode plate 300. Therefore, even if the base portion 585 is eliminated, the flow path forming portion. The position of 570 does not shift.

  As described above, according to the present embodiment, since the convex portion 480 is provided on the anode plate 400 and the concave portion 580 is provided on the flow path forming portion 570, the alignment of the flow path forming portion 570 can be facilitated. In addition, since the alignment accuracy of the flow path forming part 570 is improved, the cooling efficiency of the fuel cell is improved. Further, the load of the intermediate film 500 can be dispersed.

Modification 1:
FIG. 10 is an explanatory view for explaining various engagement structures of the convex portion 480 and the concave portion 580. In FIG. 10, the size of the convex portion 480 is drawn slightly smaller than the size of the concave portion 580 in order to clarify the positions of the convex portion 480 and the concave portion 580. FIG. 10A shows an example in which the concave portion 580 is in the center near the tip of the flow path forming portion 570. In this example, the convex portion 480 just fits into the concave portion 580. This configuration is the configuration used in the above embodiment. FIG. 10B is an example in which the two concave portions 580 are on both sides of the side portion near the tip of the flow path forming portion 570. In this example, the two convex portions 480 engage with the concave portion 580 of the flow path forming portion 570 from both sides. FIG. 10C is an example in which the recess 580 is at the top of the tip of the flow path forming part 570. In this example, the convex portion 480 engages with the concave portion 580 at the top of the flow path forming portion 570. Further, FIG. 10D is an example in which there is no recess 580. Even if there is no recess 580, the flow path forming part 570 can be aligned by sandwiching the flow path forming part 570 between the two convex parts 480.

  As the three-dimensional shape of the convex portion 480 of the anode plate 400, for example, various shapes such as a hemispherical shape, a cylindrical shape, a conical shape, a prism shape, and a pyramid shape can be adopted. Further, the size of the convex portion 480 may be larger than the size of the concave portion 580. In this way, the positioning accuracy by the convex part 480 and the concave part 580 can be improved. Further, the recess 580 may open through the intermediate film. For example, when the openings 510 to 560 and the opening 555 are punched, the recess 580 can be punched simultaneously.

Modification 2:
In this embodiment, the refrigerant flow path has been described as an example. However, a configuration in which a flow path is formed using a plurality of flow path forming members is used in, for example, a fuel gas flow path forming section and an oxidizing gas flow path forming section. Can do.

Modification 3:
In this embodiment, the convex portion 480 is formed on the anode plate 400, but the convex portion may be formed on the cathode plate 300. Moreover, although the convex part 480 is formed in the anode plate 400 and the recessed part 580 is formed in the intermediate | middle film 500, conversely, the recessed part may be formed in the anode plate 400 and the convex part may be formed in the intermediate film 500. .

Modification 4:
In this embodiment, the intermediate film 500 is made of a thermoplastic resin, but may be formed of other types of resin or metal.

Modification 5:
Various configurations other than the configurations of the above-described embodiments are possible for the positions and shapes of the various openings. In this embodiment, the fuel gas and the oxidizing gas flow in the same direction, but the fuel gas and the oxidizing gas may flow in opposite directions.

  The embodiments of the present invention have been described above based on some examples. However, the above-described embodiments of the present invention are for facilitating the understanding of the present invention and limit the present invention. It is not a thing. The present invention can be changed and improved without departing from the spirit and scope of the claims, and it is needless to say that the present invention includes equivalents thereof.

It is a perspective view which shows the external appearance of the fuel cell which concerns on a present Example. FIG. 2 is a cross-sectional view of the fuel cell 100 taken along the section line 2-2 shown in FIG. 2 is a plan view of a cathode plate 300. FIG. 4 is a plan view of an anode plate 400. FIG. It is a top view of the intermediate film 500 after the separator 30 formation. It is a top view of the intermediate film 500 before forming the separator 30. FIG. 4 is a flowchart showing manufacturing steps of the separator 30. FIG. 5 is a plan view when an intermediate film 500 is disposed on an anode plate 400. It is a comparative example about FIG. It is explanatory drawing explaining the various engagement structure of the convex part 480 and the recessed part 580. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 30 ... Separator 100 ... Fuel cell 110 ... Fuel gas supply manifold 120 ... Fuel gas discharge manifold 130 ... Oxidation gas supply manifold 140 ... Oxidation gas discharge manifold 150 ... Refrigerant supply manifold 160 ... Refrigerant discharge manifold 200 ... Power generator 202 ... End plate 210 ... Membrane electrode assembly 220 ... Anode side gas diffusion layer 230 ... Cathode side gas diffusion layer 240 ... Anode side porous body layer 250 ... Cathode side porous body layer 260 ... Seal gasket 300 ... Cathode plate 310, 320, 330, 340, 350 360 ... opening 332, 342 ... opening 400 ... anode plate 410, 420, 430, 440, 450, 460 ... opening 412, 422 ... opening 480, 490 ... convex 500: intermediate film 510 520,530,540,540,550,560 ... opening 512, 522, 532, and 542 ... communicating portion 555 ... opening 570 ... passage forming portion 575 ... passage 580 ... recess 585 ... base portion

Claims (8)

A fuel cell separator,
An intermediate member, and first and second plates sandwiching the intermediate member from both sides,
The intermediate member has a plurality of flow path forming portions arranged to be separated from each other,
The first plate includes a plurality of positioning portions for positioning the plurality of flow path forming portions when the separator is assembled. The fuel cell separator according to claim 1,
The said positioning part is a separator for fuel cells which is a convex part protruded to the said intermediate member side. The fuel cell separator according to claim 2,
The said flow path formation part is a separator for fuel cells which has a recessed part engaged with the said convex part. The fuel cell separator according to any one of claims 1 to 3,
The flow path forming portion is formed in a shape connected to an outer edge portion of the intermediate member before the separator is formed,
A fuel cell separator having a configuration in which the intermediate member and the first and second plates are separated from and separated from the outer edge portion after joining. In the fuel cell separator according to any one of claims 1 to 4,
The fuel cell separator, wherein the intermediate member is formed of a thermoplastic resin and joined to the first and second plates by thermal welding. In the fuel cell separator according to any one of claims 2 to 5,
A refrigerant flow path is formed between the first and second plates;
Part of the refrigerant flow path is a fuel cell separator formed using a convex portion formed on the first plate. A fuel cell,
A fuel cell comprising the fuel cell separator according to any one of claims 1 to 6. A method for producing a separator for a fuel cell, comprising:
(A) preparing an intermediate member having a plurality of flow path forming portions and an outer edge portion formed integrally with the plurality of flow path forming portions;
(B) preparing a first plate having a plurality of positioning portions used for positioning of the plurality of flow path forming portions, and a second plate;
(C) sandwiching the intermediate member between the first and second plates while positioning the plurality of flow path forming portions using the plurality of positioning portions;
(D) joining the first and second plates and the intermediate member;
(E) separating the plurality of flow path forming portions from the outer edge portion and separating the plurality of flow path forming portions from each other;
The manufacturing method of the separator for fuel cells provided with.

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