JP2007207570A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell with further improved cooling efficiency, capable of easily and surely controlling flow amount of cooling media in a separator face. <P>SOLUTION: A plurality of first convex parts 44 are formed on a backside of a fuel gas flow passage 42 by arranging the fuel gas flow passage 42 on a first separator 24, and second convex parts 48 are formed on a backside of an oxidant gas flow passage 46 by arranging the oxidant gas flow passage 46 on a second separator 26. First top faces 44a of the first convex parts 44 and second top faces 48a of the second convex parts 48 constitute a continuous contact part 52 for forming separation parts 50 forming cooling media flow passages 54, and sealing areas preventing the cooling media from flowing. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel cell in which an electrolyte / electrode structure in which an anode electrode and a cathode electrode are provided on both sides of an electrolyte, and a separator are laminated.

  For example, a solid polymer fuel cell employs a solid polymer electrolyte membrane made of a polymer ion exchange membrane. This fuel cell has an electrolyte membrane / electrode structure in which an anode side electrode and a cathode side electrode made of an electrode catalyst (electrode catalyst layer) and porous carbon (diffusion layer) are arranged on both sides of a solid polymer electrolyte membrane, respectively. The power generation cell (unit cell) is sandwiched between separators (bipolar plates). Usually, in a fuel cell, a fuel cell stack in which a predetermined number of power generation cells are stacked is used.

  In the above fuel cell, as the separator, for example, a metal separator composed of a thin metal plate may be used. In this metal separator, when a reaction gas channel (a fuel gas channel or an oxidant gas channel) is formed on one surface by pressing, the other surface is determined by the shape of the reaction gas channel. Thus, a cooling medium flow path (or other reaction gas flow path) is formed. For this reason, there exists a problem that a cooling medium cannot be flowed favorably along a cooling medium flow path depending on the shape of the reaction gas flow path.

  Therefore, in the fuel cell disclosed in Patent Document 1, the first and second separators sandwiching the electrolyte / electrode assembly have long first portions having hollow portions for circulating fuel gas and oxidant gas. And the second hollow convex portion, and the top surfaces of the first hollow convex portion and the second hollow convex portion are partially separated from each other, thereby forming a space for circulating the cooling medium. .

  With such a configuration, cooling water can be circulated between unit cells adjacent to each other without using a spacer or the like, and a fuel cell that is lightweight and small but has excellent cooling efficiency can be obtained. Become.

Japanese Patent Laid-Open No. 2003-338300 (FIG. 4)

  The present invention relates to a fuel cell of this type, and in particular, to provide a fuel cell capable of easily and surely controlling the flow rate of the cooling medium in the separator surface and further improving the cooling efficiency. With the goal.

  The present invention relates to a fuel cell in which an electrolyte / electrode structure in which an anode electrode and a cathode electrode are provided on both sides of an electrolyte, and one or more separators are alternately stacked.

  The two or more separators have first and second separators that overlap each other in the stacking direction, and the first separator has a plurality of first recesses for fuel gas passages through which the fuel gas supplied to the anode-side electrode flows. A long convex or curved first convex part is formed on the back side of the first concave part. The second separator is provided with a plurality of second oxidant gas channel recesses for circulating the oxidant gas supplied to the cathode side electrode, and is opposed to the first convex part on the back surface side of the second recesses. In addition, a long, bent or curved second convex portion extending in the same direction as the first convex portion is formed.

  And the 1st top surface of the 1st convex part and the 2nd top surface of the 2nd convex part are separated from each other, and a separation part for providing a cooling medium channel which distributes a cooling medium in the separator surface direction And a continuous contact portion for forming a sealing region that contacts with each other over a predetermined length in the stacking direction and prevents the flow of the cooling medium along the flow direction of the cooling medium flow path.

  The first and second convex portions have first and second bent portions that are alternately bent in different directions in succession, and in the separation portion, the amplitude and length of the first and second bent portions are set. Are the same and have different phases, and in the continuous contact portion, the phases of the first and second bent portions preferably match.

  According to the present invention, the cooling medium flow path is formed with a plurality of flow paths substantially because the cooling medium flow path is formed with a sealing region that prevents the flow of the cooling medium through the continuous contact portion. Divided into road sections. Therefore, for example, only the flow rate of the specific flow path portion in the cooling medium flow path can be changed. Thereby, the flow control of the cooling medium in the separator surface can be easily and reliably performed, the temperature distribution in the separator surface can be controlled well, and the cooling efficiency can be further improved.

  FIG. 1 is a schematic perspective view of a fuel cell 10 according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of a main part of a power generation cell 12 constituting the fuel cell 10.

  The fuel cell 10 includes a stacked body 14 in which a plurality of power generation cells 12 are stacked in the direction of arrow A. Terminal plates 16a and 16b, insulating plates 18a and 18b, and end plates 20a and 20b are disposed at both ends in the stacking direction of the laminate 14, and a predetermined tightening load is applied between the end plates 20a and 20b. Has been. The fuel cell 10 may be configured by housing the laminate 14 in a box-shaped casing (not shown).

  As shown in FIG. 2, the power generation cell 12 includes an electrolyte membrane (electrolyte) / electrode structure 22, and first and second separators 24 and 26 that sandwich the electrolyte membrane / electrode structure 22. The 1st and 2nd separators 24 and 26 are comprised by the vertically long metal plate.

  An oxidant gas supply for supplying an oxidant gas, for example, an oxygen-containing gas, communicates with one end edge (upper edge) in the arrow C direction of the power generation cell 12 in the arrow A direction which is the stacking direction. A communication hole 30a and a fuel gas supply communication hole 32a for supplying fuel gas are arranged in the direction of arrow B.

  The other end edge (lower end edge) of the power generation cell 12 in the direction of arrow C communicates with each other in the direction of arrow A, which is the stacking direction, and an oxidant gas discharge communication hole 30b for discharging oxidant gas, and Fuel gas discharge communication holes 32b for discharging the fuel gas are arranged in the direction of arrow B.

  At one end edge of the power generation cell 12 in the arrow B direction, four cooling medium supply communication holes 34a are arranged in the arrow C direction so as to communicate with each other in the direction of arrow A, which is the stacking direction. Provided. At the other end edge of the power generation cell 12 in the arrow B direction, four cooling medium discharge communication holes 34b are arranged in the arrow C direction so as to communicate with each other in the direction of arrow A, which is the stacking direction. Provided.

  The electrolyte membrane / electrode structure 22 includes, for example, a solid polymer electrolyte membrane 36 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side electrode 38 and a cathode side electrode 40 that sandwich the solid polymer electrolyte membrane 36. With.

  The anode side electrode 38 and the cathode side electrode 40 are uniformly coated on the surface of the gas diffusion layer with a gas diffusion layer (not shown) made of carbon paper or the like and porous carbon particles carrying a platinum alloy on the surface. An electrode catalyst layer (not shown). The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 36.

  As shown in FIG. 3, a fuel gas flow path 42 communicating with the fuel gas supply communication hole 32a and the fuel gas discharge communication hole 32b is formed on the surface 24a of the first separator 24 on the electrolyte membrane / electrode structure 22 side. Is done.

  The fuel gas channel 42 has a plurality of fuel gas channel grooves (first recesses) 42a that are alternately bent to the left and right, that is, zigzag and meander in the direction of the arrow C. By providing each fuel gas flow channel groove 42a on the back surface side of the fuel gas flow channel 42, that is, on the surface 24b side of the first separator 24, a long bend (or curve) protruding toward the surface 24b side is provided. ) Are formed (see FIG. 2). As shown in FIG. 4, the first top surface 44 a of each first convex portion 44 is formed in a zigzag manner and is provided in parallel with the surface 24 b of the first separator 24. Each of the first top surfaces 44a is set to have a length H1 between the one crests.

  As shown in FIG. 2, an oxidant gas flow path communicating with the oxidant gas supply communication hole 30a and the oxidant gas discharge communication hole 30b is formed on the surface 26a of the second separator 26 on the electrolyte membrane / electrode structure 22 side. 46 is formed. The oxidant gas flow path 46 has a plurality of oxidant gas flow path grooves (second recesses) 46a that are alternately bent left and right, that is, meandering flow paths zigzag extending in the direction of arrow C.

  On the back surface side of each oxidant gas flow channel groove 46a, that is, as shown in FIG. 5, on the surface 26b side of the second separator 26, a second protrusion that is bent (or curved) long in the direction of arrow C. A shaped portion 48 is formed. The second top surface 48a of the second convex portion 48 protrudes from the surface 26b of the second separator 26 and is formed parallel to the surface 26a (see FIG. 4).

  Each second top surface 48a is alternately bent in the left-right direction (arrow A direction) in the direction of arrow C, and a region having a length H1 and a length H2 (= 2) between one peak. A region having xH1). The region having the length H1 corresponds to the opening width dimension of the cooling medium supply communication hole 34a and the cooling medium discharge communication hole 34b along the arrow A direction, while the region having the length H2 is the cooling medium supply communication hole. 34a and between the cooling medium discharge communication holes 34b.

  In the region corresponding to the length H1 of the second top surface 48a, the amplitude and length H1 of the second top surface 48a are the same as the amplitude and length H1 of the first top surface 44a of the first convex portion 44, and The phase is reversed, and the separation portion 50 is formed. In the region having the length H <b> 2 of the second top surface 48 a, the phases of the first top surface 44 a coincide with each other and are in contact with each other, and constitute a continuous contact portion 52.

  A first seal member 53 a is integrally formed on the surfaces 24 a and 24 b of the first separator 24 around the outer peripheral edge of the first separator 24. A second seal member 53 b is integrally formed on the surfaces 26 a and 26 b of the second separator 26 so as to go around the outer peripheral edge of the second separator 26.

  Therefore, the first separator 24 constituting the one power generation cell 12 and the second separator 26 constituting the other power generation cell 12 are overlapped with each other, so that the first and second convex portions 44 and 48 are first. The second top surfaces 44a and 48a are spaced apart from each other, that is, a spacing portion 50 is provided. Corresponding to the separation portion 50, a cooling medium flow path 54 for circulating the cooling medium in the separator surface direction is provided.

  Moreover, the area | region where the 1st and 2nd top surfaces 44a and 48a mutually contact in a lamination direction over predetermined length, ie, the continuous contact part 52, is provided. In the continuous contact portion 52, a sealing region that prevents the flow of the cooling medium along the flow direction of the cooling medium flow path 54 is configured.

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

  The fuel cell 10 is supplied with an oxidant gas that is an oxygen-containing gas such as air, a fuel gas such as a hydrogen-containing gas, and a cooling medium such as pure water or ethylene glycol. For this reason, as shown in FIG. 2, an oxidant gas is introduced into the oxidant gas flow path 46 of the second separator 26 from the oxidant gas supply communication hole 30a, and this oxidant gas flows into each oxidant gas flow path groove 46a. Is moved in a vertical downward direction along the cathode side electrode 40 constituting the electrolyte membrane / electrode structure 22.

  On the other hand, the fuel gas is introduced into the fuel gas flow path 42 of the first separator 24 from the fuel gas supply communication hole 32a. As shown in FIG. 3, the fuel gas moves in a vertically downward direction along the anode-side electrode 38 constituting the electrolyte membrane / electrode structure 22 by flowing in zigzags through each fuel gas flow channel groove 42 a. Therefore, in the electrolyte membrane / electrode structure 22, the oxidant gas supplied to the cathode side electrode 40 and the fuel gas supplied to the anode side electrode 38 are consumed by an electrochemical reaction in the electrode catalyst layer, thereby generating power. Is done.

  The oxidant gas consumed by being supplied to the cathode side electrode 40 is discharged in the direction of arrow A along the oxidant gas discharge communication hole 30b. Similarly, the fuel gas consumed by being supplied to the anode electrode 38 is discharged in the direction of arrow A along the fuel gas discharge communication hole 32b.

  The cooling medium supplied to the cooling medium supply communication hole 34a is introduced into the cooling medium flow path 54 between the first and second separators 24 and 26 and then circulates in the direction of arrow B. This cooling medium is discharged from the cooling medium discharge communication hole 34b after the electrolyte membrane / electrode structure 22 is cooled.

  In this case, in this embodiment, as shown in FIG. 4, the first top surface 44 a of the first convex portion 44 and the second top surface 48 a of the second convex portion 48 correspond to the spacing portion 50. A cooling medium flow path 54 is provided for circulating the cooling medium in the separator surface direction by reversing the phases.

  On the other hand, between the cooling medium supply communication holes 34a and between the cooling medium discharge communication holes 34b, the first and second top surfaces 44a and 48a contact each other in the stacking direction over a predetermined length H2, and the continuous contact portion 52 Is provided. For this reason, the cooling medium flow path 54 is substantially divided into four cooling medium flow path portions 54a, 54b, 54c and 54d.

  Therefore, the flow rate of a specific flow path part in the cooling medium flow path 54, for example, the cooling medium flow path part 54a can be set higher than the flow rates of the other cooling medium flow path parts 54b to 54d. It becomes possible to effectively cool the vicinity of the remarkable oxidizing gas supply communication hole 30a and the fuel gas supply communication hole 32a. Thereby, the flow rate control of the cooling medium in the separator surface can be easily and reliably performed, the temperature distribution in the separator surface can be controlled well, and the cooling efficiency can be further improved. .

  In the present embodiment, the power generation cell 12 includes the electrolyte membrane / electrode structure 22 and the first and second separators 24 and 26, and the power generation cells 12 are stacked to form the electrolyte membrane / electrode structure. Between the body 22, 24 and 26 which are the 1st and 2nd which are two separators are interposed. That is, a cooling medium flow path 54 is formed between each electrolyte membrane / electrode structure 22.

  Instead of this, for example, two separators may be stacked on one side of the electrolyte membrane / electrode structure 22, and one separator may be stacked on the other side of the electrolyte membrane / electrode structure 22. That is, a so-called thinning cooling structure in which every other cooling medium flow path 54 is formed between the electrolyte membrane / electrode structures 22 may be employed.

  Moreover, although the 1st and 2nd convex-shaped parts 44 and 48 are comprised by the zigzag, it may replace with this and may comprise a curve.

1 is a schematic perspective view of a fuel cell according to an embodiment of the present invention. It is a principal part disassembled perspective view of the electric power generation cell which comprises the said fuel cell. It is a front view of the 1st separator which comprises the said electric power generation cell. It is a perspective explanatory view of the 1st and 2nd convex part which constitutes the power generation cell. It is a front view of the 2nd separator which constitutes the power generation cell.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell 12 ... Power generation cell 14 ... Laminated body 22 ... Electrolyte membrane electrode assembly 24, 26 ... Separator 30a ... Oxidant gas supply communication hole 30b ... Oxidant gas discharge communication hole 32a ... Fuel gas supply communication hole 32b ... Fuel gas discharge communication hole 34a ... Cooling medium supply communication hole 34b ... Cooling medium discharge communication hole 36 ... Solid polymer electrolyte membrane 38 ... Anode side electrode 40 ... Cathode side electrode 42 ... Fuel gas flow path 42a ... Fuel gas flow path groove 44 48 ... convex portions 44a, 48a ... top surface 46 ... oxidant gas flow path 46a ... oxidant gas flow path groove 50 ... separation part 52 ... continuous contact part 54 ... cooling medium flow path

Claims (2)

A fuel cell in which an electrolyte / electrode structure in which an anode side electrode and a cathode side electrode are provided on both sides of an electrolyte, and one or more separators are alternately stacked,
The two or more separators have first and second separators that overlap each other in the stacking direction,
The first separator is provided with a plurality of first recesses for a fuel gas flow path through which the fuel gas supplied to the anode-side electrode is circulated, and a long bend or curve is formed on the back side of the first recess. A first convex portion is formed;
The second separator is provided with a plurality of second oxidant gas channel recesses for circulating an oxidant gas supplied to the cathode side electrode, and on the back side of the second recess, the first convex shape A second convex portion that is long and bends or curves opposite to the portion and extends in the same direction as the first convex portion,
The first top surface of the first convex portion and the second top surface of the second convex portion are spaced apart from each other and provided with a cooling medium flow path for circulating the cooling medium in the separator surface direction. ,
A continuous contact portion for forming a sealing region that is in contact with each other over a predetermined length in the stacking direction and prevents the flow of the cooling medium along the flow direction of the cooling medium flow path;
A fuel cell comprising: 2. The fuel cell according to claim 1, wherein the first and second convex portions have first and second bent portions that are alternately bent in different directions in succession,
In the separation portion, the amplitude and length of the first and second bent portions are the same and have different phases,
In the continuous contact portion, the phase of the first bent portion and the second bent portion coincide with each other.

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