JP2015185500A - Fuel cell stack - Google Patents

Abstract

A power generation unit including two MEAs and three separators can be produced economically, and the complexity of equipment can be suppressed.
A fuel cell stack includes a plurality of power generation units. The second separator 18 constituting each power generation unit 12 has a flat plate shape, and a first porous body 36a forming a first oxidant gas flow channel 48 is formed on one flat surface of the second separator 18. Provided. On the other flat surface of the second separator 18, a second porous body 36 b that forms the second fuel gas channel 52 is provided.
[Selection] Figure 2

Description

  The present invention relates to a fuel cell stack including a plurality of power generation units stacked in the order of a first separator, a first electrolyte / electrode structure, a second separator, a second electrolyte / electrode structure, and a third separator.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure in which an anode electrode is disposed on one side of an electrolyte membrane made of a polymer ion exchange membrane and a cathode electrode is disposed on the other surface side ( MEA). The electrolyte membrane / electrode structure constitutes a power generation cell by being sandwiched between separators. A fuel cell is usually incorporated in a fuel cell electric vehicle as an in-vehicle fuel cell stack, for example, by stacking a predetermined number of power generation cells.

  In the fuel cell, a fuel gas flow channel for flowing fuel gas is provided in the plane of one separator so as to face the anode electrode, and an oxidant gas is provided in the face of the other separator so as to face the cathode electrode. Is provided with an oxidant gas flow path. Furthermore, between the separators, a cooling medium flow path for flowing a cooling medium is provided along the surface direction of the separator.

  By the way, the fuel cell stack may adopt a so-called thinning cooling structure in which a cooling medium flow path is formed between a predetermined number of power generation cells (unit cells). A fuel cell having this type of thinning cooling structure includes, for example, a first separator 1, a first cell 2, a second separator 3, a second cell 4, and a third separator 5 as disclosed in Patent Document 1. They are stacked (see FIG. 4).

  In the first cell 2, the fuel electrode 2b and the air electrode 2c are disposed on both surfaces of the solid polymer electrolyte membrane 2a. The second cell 4 is configured in the same manner as the first cell 2. A first fuel gas passage 6 a is formed between the first separator 1 and the first cell 2, and a first oxidant gas passage 7 a is formed between the second separator 3 and the first cell 2. Has been. A second fuel gas passage 6b is formed between the second separator 3 and the second cell 4, and a second oxidant gas passage 7b is formed between the third separator 5 and the second cell 4. Is formed. A cooling water passage 8 is formed between the first separator 1 and the third separator 5 adjacent to each other.

JP 2002-289223 A

  In said patent document 1, the 1st separator 1, the 2nd separator 3, and the 3rd separator 5 which comprise a fuel cell have a respectively different shape. Therefore, press molds having different shapes corresponding to the respective separators are required. Accordingly, there are problems that the facilities become complicated and the manufacturing cost of the entire fuel cell rises.

  The present invention solves this type of problem, and it is possible to economically manufacture a power generation unit including two MEAs and three separators, and to prevent equipment from becoming complicated. An object is to provide a possible fuel cell stack.

  The fuel cell stack according to the present invention includes a first electrolyte / electrode structure and a second electrolyte / electrode structure in which electrodes are disposed on both sides of the electrolyte. The fuel cell stack includes a plurality of power generation units that are stacked in the order of a first separator, a first electrolyte / electrode structure, a second separator, a second electrolyte / electrode structure, and a third separator.

  Between the 1st separator and the 1st electrolyte and electrode structure, the 1st fuel gas flow path through which fuel gas flows along a power generation surface is formed. Between the first electrolyte / electrode structure and the second separator, a first oxidant gas flow path is formed along which the oxidant gas flows along the power generation surface. Between the second separator and the second electrolyte / electrode structure, a second fuel gas flow channel is formed along which the fuel gas flows along the power generation surface. Between the second electrolyte / electrode structure and the third separator, a second oxidant gas flow path is formed along which the oxidant gas flows along the power generation surface. A cooling medium flow path through which the cooling medium flows is formed between the power generation units.

  The second separator has a flat plate shape, and a first porous body that forms a first oxidant gas flow path is provided on one flat surface of the second separator. A second porous body that forms a second fuel gas flow path is provided on the other flat surface of the second separator.

  In the fuel cell stack, the second separator preferably includes a flat metal plate, and an insulating resin frame member is provided on the outer peripheral edge of the metal plate.

  According to the present invention, the second separator has a flat plate shape, and on one flat surface, the first porous body forming the first oxidant gas flow path is provided, and on the other flat surface. Is provided with a second porous body forming a second fuel gas flow path. For this reason, the second separator does not require a press molding die or the like. Therefore, it is possible to economically manufacture a power generation unit including two MEAs and three separators, and it is possible to favorably suppress the equipment from becoming complicated.

It is a principal part disassembled perspective explanatory drawing of the fuel cell which comprises the fuel cell stack which concerns on embodiment of this invention. FIG. 2 is a cross-sectional view of the fuel cell stack taken along line II-II in FIG. 1. It is front explanatory drawing of the 2nd separator which comprises the said fuel cell stack. 2 is a cross-sectional explanatory view of a fuel cell disclosed in Patent Document 1. FIG.

  As shown in FIGS. 1 and 2, a fuel cell stack 10 according to an embodiment of the present invention is mounted on, for example, a fuel cell electric vehicle (not shown). In the fuel cell stack 10, a plurality of power generation units 12 are stacked in the horizontal direction (arrow A direction) with the electrode surface in a standing posture. Note that the fuel cell stack 10 may be configured by stacking a plurality of power generation units 12 in the direction of gravity (arrow C direction).

  The power generation unit 12 includes a first separator 14, a first electrolyte membrane / electrode structure (electrolyte / electrode structure) (MEA) 16a, a second separator 18, a second electrolyte membrane / electrode structure (electrolyte / electrode structure). (MEA) 16b and the third separator 20 are included.

  The first electrolyte membrane / electrode structure 16a includes, for example, a solid polymer electrolyte membrane 22 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode electrode 24a and a cathode electrode 26a sandwiching the solid polymer electrolyte membrane 22 With. The second electrolyte membrane / electrode structure 16b includes, for example, a solid polymer electrolyte membrane 22 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode electrode 24b and a cathode electrode 26b sandwiching the solid polymer electrolyte membrane 22 With.

  In the first electrolyte membrane / electrode structure 16a, the anode electrode 24a constitutes a step MEA having a smaller planar dimension than the solid polymer electrolyte membrane 22 and the cathode electrode 26a, but is not limited thereto. . For example, the anode electrode 24a may have a larger planar dimension than the cathode electrode 26a, or may have the same planar dimension as the cathode electrode 26a.

  In the second electrolyte membrane / electrode structure 16b, the cathode electrode 26b constitutes a step MEA having a smaller planar dimension than the solid polymer electrolyte membrane 22 and the anode electrode 24b, but is not limited thereto. . For example, the cathode electrode 26b may have a larger planar dimension than the anode electrode 24b, or may have the same planar dimension as the anode electrode 24b.

  The anode electrodes 24a and 24b and the cathode electrodes 26a and 26b have a gas diffusion layer (not shown) made of carbon paper or the like and an electrode catalyst layer (not shown). The electrode catalyst layer is formed by uniformly applying porous carbon particles having a platinum alloy supported on the surface thereof to the surface of the gas diffusion layer. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 22, for example.

  As shown in FIG. 1, at one end edge of the long side direction (arrow B direction) of the power generation unit 12, there is an oxidant gas inlet communication hole 30a and a fuel gas outlet communication hole 32b communicating with each other in the arrow A direction. The cooling medium inlet communication hole 34a is vertically sandwiched. The oxidant gas inlet communication hole 30a supplies an oxidant gas, for example, an oxygen-containing gas, the fuel gas outlet communication hole 32b discharges a fuel gas, for example, a hydrogen-containing gas, and the cooling medium inlet communication hole 34a Supply cooling medium.

  A fuel gas inlet communication hole 32a and an oxidant gas outlet communication hole 30b communicate with each other in the direction of arrow A at the other end edge of the power generation unit 12 in the long side direction (arrow B direction). 34b is provided between the upper and lower sides. The fuel gas inlet communication hole 32a supplies fuel gas, the oxidant gas outlet communication hole 30b discharges the oxidant gas, and the cooling medium outlet communication hole 34b discharges the cooling medium.

  The 1st separator 14, the 2nd separator 18, and the 3rd separator 20 are comprised by the vertically long metal plate which gave the surface treatment for anticorrosion to the metal surface, for example, a steel plate, a stainless steel plate, an aluminum plate, a plating treatment steel plate. Is done. The first separator 14, the second separator 18, and the third separator 20 may be constituted by, for example, a carbon separator instead of the metal separator.

  As shown in FIG. 2, the 1st separator 14 and the 3rd separator 20 have the metal thin plates 14P and 20P whose plane is a rectangular shape. As shown in FIG. 2, the metal thin plates 14 </ b> P and 20 </ b> P are formed into a concavo-convex shape by being pressed into a wave shape.

  The second separator 18 includes a flat metal plate 18P and has a flat plate shape with flat both surfaces as a whole. A first porous body 36a is provided on one flat surface of the metal plate 18P (a flat surface facing the first electrolyte membrane / electrode structure 16a). A second porous body 36b is provided on the other flat surface of the metal plate 18P (a flat surface facing the second electrolyte membrane / electrode structure 16b). The first porous body 36a and the second porous body 36b are made of, for example, titanium (Ti) porous sintered metal, porous conductive ceramics, or a porous carbon-based material.

  On one flat surface of the metal plate 18P, an insulating resin frame member 38a is provided around the outer peripheral portion of the first porous body 36a. On the other flat surface of the metal plate 18P, an insulating resin frame member 38b is provided around the outer periphery of the second porous body 36b. The insulating resin frame members 38a and 38b are respectively bonded to both surfaces of the metal plate 18P, and airtightness is ensured between the insulating resin frame members 38a and 38b and the metal plate 18P.

  As shown in FIG. 1, the first fuel gas flow that communicates the fuel gas inlet communication hole 32a and the fuel gas outlet communication hole 32b to the surface 14a of the first separator 14 facing the first electrolyte membrane / electrode structure 16a. A path 40 is formed. The first fuel gas channel 40 has, for example, a plurality of linear grooves extending in the arrow B direction. The first fuel gas channel 40 may have a curved portion or a bent portion, or may be a wave-like channel or a serpentine channel.

  The inlet side of the first fuel gas flow path 40 and the fuel gas inlet communication hole 32a communicate with each other via a plurality of supply connection paths 42a formed on the surface 14a. The outlet side of the first fuel gas flow path 40 and the fuel gas outlet communication hole 32b communicate with each other via a plurality of discharge connection paths 42b formed on the surface 14a. A lid 44a and a lid 44b are disposed on the supply coupling path 42a and the discharge coupling path 42b.

  A part of the cooling medium flow path 46 that connects the cooling medium inlet communication hole 34 a and the cooling medium outlet communication hole 34 b is formed on the surface 14 b of the first separator 14. The shape of a part of the cooling medium channel 46 is the back surface shape of the first fuel gas channel 40.

  As shown in FIG. 3, the surface 18a of the second separator 18 facing the first electrolyte membrane / electrode structure 16a is connected to the oxidant gas inlet communication hole 30a and the oxidant gas outlet communication hole 30b. An agent gas channel 48 is formed. The first oxidant gas flow path 48 is formed by the internal cavity of the first porous body 36a.

  A plurality of supply connection passages 50 a and a plurality of discharge connection passages 50 b are formed by convex portions in the vicinity of the inlet and the outlet of the first oxidant gas passage 48. The supply connection channel 50a communicates the inlet side of the first oxidant gas channel 48 and the oxidant gas inlet communication hole 30a. The discharge connection path 50b communicates the outlet side of the first oxidant gas flow path 48 and the oxidant gas outlet communication hole 30b.

  As shown in FIG. 1, the second fuel gas flow that communicates the fuel gas inlet communication hole 32a and the fuel gas outlet communication hole 32b to the surface 18b of the second separator 18 facing the second electrolyte membrane / electrode structure 16b. A path 52 is formed. The second fuel gas channel 52 is formed by the internal cavity of the second porous body 36b.

  A plurality of supply connection passages 53 a and a plurality of discharge connection passages 53 b are formed by convex portions in the vicinity of the inlet and the outlet of the second fuel gas passage 52. The supply connection path 53a communicates the inlet side of the second fuel gas flow path 52 with the fuel gas inlet communication hole 32a. The discharge connection path 53b communicates the outlet side of the second fuel gas flow path 52 and the fuel gas outlet communication hole 32b.

  On the surface 20a of the third separator 20 facing the second electrolyte membrane / electrode structure 16b, a second oxidant gas flow channel 54 is formed to communicate the oxidant gas inlet communication hole 30a and the oxidant gas outlet communication hole 30b. Is done. The second oxidant gas channel 54 has, for example, a plurality of linear grooves extending in the arrow B direction. The second oxidizing gas channel 54 may have a curved portion or a bent portion, or may be a wave-like channel or a serpentine channel.

  The inlet side of the second oxidant gas flow channel 54 and the oxidant gas inlet communication hole 30a communicate with each other through a plurality of supply connection paths (not shown) formed on the surface 20a. The outlet side of the second oxidant gas flow channel 54 and the oxidant gas outlet communication hole 30b communicate with each other via a plurality of discharge communication passages (not shown) formed in the surface 20a. A lid (not shown) is disposed in the supply connection path and the discharge connection path.

  A part of the cooling medium flow path 46 that connects the cooling medium inlet communication hole 34 a and the cooling medium outlet communication hole 34 b is formed on the surface 20 b of the third separator 20. The shape of a part of the cooling medium channel 46 is the back surface shape of the second oxidant gas channel 54.

  As shown in FIGS. 1 and 2, the first seal member 56 is integrally formed on the surfaces 14 a and 14 b of the first separator 14 around the outer peripheral edge of the first separator 14. In the second separator 18, the second seal members 58a and 58b are integrally formed or individually disposed on the insulating resin frame members 38a and 38b. A third seal member 60 is integrally formed on the surfaces 20 a and 20 b of the third separator 20 around the outer peripheral edge of the third separator 20.

  As the first seal member 56, the second seal members 58a, 58b, and the third seal member 60, for example, EPDM, NBR, fluororubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroplane or acrylic An elastic sealing member such as a sealing material such as rubber, a cushioning material, or a packing material is used.

  The operation of the fuel cell stack 10 configured as described above will be described below.

  As shown in FIG. 1, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 30a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 32a. The Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 34a.

  The oxidant gas is introduced into the first oxidant gas channel 48 of the second separator 18 and the second oxidant gas channel 54 of the third separator 20 from the oxidant gas inlet communication hole 30a. The oxidant gas moves in the arrow B direction (horizontal direction) along the first oxidant gas flow path 48 and is supplied to the cathode electrode 26a of the first electrolyte membrane / electrode structure 16a. Further, the remaining oxidant gas moves in the direction of arrow B along the second oxidant gas flow path 54 and is supplied to the cathode electrode 26b of the second electrolyte membrane / electrode structure 16b.

  On the other hand, the fuel gas moves in the horizontal direction (arrow B direction) along the first fuel gas flow path 40 of the first separator 14 from the fuel gas inlet communication hole 32a, and the anode of the first electrolyte membrane / electrode structure 16a. It is supplied to the electrode 24a. Further, the remaining fuel gas moves from the fuel gas inlet communication hole 32a in the direction of arrow B along the second fuel gas flow path 52 of the second separator 18, and the anode electrode 24b of the second electrolyte membrane / electrode structure 16b. To be supplied.

  Therefore, in the first electrolyte membrane / electrode structure 16a and the second electrolyte membrane / electrode structure 16b, the oxidant gas supplied to the cathode electrodes 26a and 26b and the fuel gas supplied to the anode electrodes 24a and 24b In the electrode catalyst layer, power is generated by being consumed by an electrochemical reaction.

  Next, the oxidant gas supplied to and consumed by the cathode electrodes 26a and 26b of the first electrolyte membrane / electrode structure 16a and the second electrolyte membrane / electrode structure 16b travels along the oxidant gas outlet communication hole 30b. Circulate in the direction of arrow A. The fuel gas supplied to and consumed by the anode electrodes 24a and 24b of the first electrolyte membrane / electrode structure 16a and the second electrolyte membrane / electrode structure 16b flows in the direction of arrow A along the fuel gas outlet communication hole 32b. Circulate.

  On the other hand, the cooling medium supplied to the cooling medium inlet communication hole 34 a is the cooling formed between the first separator 14 constituting one power generation unit 12 and the third separator 20 constituting the other power generation unit 12. It is introduced into the medium flow path 46. The cooling medium moves in the direction of arrow B (horizontal direction), cools the first electrolyte membrane / electrode structure 16a and the second electrolyte membrane / electrode structure 16b, and then moves along the cooling medium outlet communication hole 34b. Circulate in the direction.

  In this case, in the present embodiment, as shown in FIG. 2, the second separator 18 includes a flat metal plate 18P. A first porous body 36a is provided on one flat surface of the metal plate 18P, and a second porous body 36b is provided on the other flat surface of the metal plate 18P. The first oxidant gas flow path 48 is constituted by the first porous body 36a, while the second fuel gas flow path 52 is constituted by the second porous body 36b.

  For this reason, the second separator 18 does not require a press molding (and LIMS) mold or the like. Accordingly, the power generation unit 12 including the first separator 14, the first electrolyte membrane / electrode structure 16a, the second separator 18, the second electrolyte membrane / electrode structure 16b, and the third separator 20 is economically manufactured. And simplification of the facility can be performed easily.

  Further, in the present embodiment, the first electrolyte membrane / electrode structure 16a and the second electrolyte membrane / electrode structure 16b have the same shape. In this way, for example, two first electrolyte membrane / electrode structures 16a are prepared, one is used as the first electrolyte membrane / electrode structure 16a, and the other is inverted to form a second electrolyte membrane / electrode structure. It can be used as the body 16b. For this reason, the effect that it is economical is acquired.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell stack 12 ... Electric power generation unit 14, 18, 20 ... Separator 16a, 16b ... Electrolyte membrane and electrode structure 22 ... Solid polymer electrolyte membrane 24a, 24b ... Anode electrode 26a, 26b ... Cathode electrode 30a ... Oxidant gas Inlet communication hole 30b ... Oxidant gas outlet communication hole 32a ... Fuel gas inlet communication hole 32b ... Fuel gas outlet communication hole 34a ... Cooling medium inlet communication hole 34b ... Cooling medium outlet communication hole 36a, 36b ... Porous bodies 38a, 38b ... Insulating resin frame member 40, 52 ... Fuel gas passage 46 ... Cooling medium passage 48, 54 ... Oxidant gas passage

Claims (2)

A first separator / electrode structure and a second electrolyte / electrode structure having electrodes disposed on both sides of the electrolyte, the first separator, the first electrolyte / electrode structure, the second separator, and the second electrolyte A plurality of power generation units stacked in the order of an electrode structure and a third separator are provided, and a first fuel gas flows between the first separator and the first electrolyte / electrode structure along the power generation surface. A fuel gas flow path is formed, and a first oxidant gas flow path for flowing an oxidant gas along the power generation surface is formed between the first electrolyte / electrode structure and the second separator, Between the second separator and the second electrolyte / electrode structure, there is formed a second fuel gas flow path for flowing the fuel gas along the power generation surface, and the second electrolyte / electrode structure and the second 3 separators along the power generation surface Together with the second oxidant gas passage for flowing a serial oxidant gas is formed, between each of the power generation unit, a fuel cell stack cooling medium flow path is formed to flow a cooling medium,
The second separator has a flat plate shape,
A first porous body forming the first oxidant gas flow path is provided on one flat surface of the second separator, and the second fuel is formed on the other flat surface of the second separator. A fuel cell stack comprising a second porous body that forms a gas flow path. The fuel cell stack according to claim 1, wherein the second separator includes a flat metal plate,
A fuel cell stack, wherein an insulating resin frame member is provided on an outer peripheral edge portion of the metal plate.

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