JP2010061994A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve power generation performance of a fuel cell by enlarging the cross sectional area of a gas flow path for more uniform gas supply in the gas flow path. <P>SOLUTION: Since strand parts ST constituting a mesh of an expand metal 28 are connected in steps in FD direction by bond parts BO provided in the intermediate position in WD direction, a large opening 30 and a small opening 32 are formed, alternately in FD direction and TD direction at the expand metal 28. Gas flows of a variety of systems, not only a gas flow GF<SB>0</SB>of such mode as turns are made repeatedly only through the large opening 30 but also a gas flow GF<SB>1</SB>or the like flowing both the large opening 30 and the small opening 32, are formed. Thus, the cross sectional area of gas flow path 16 is substantially enlarged for an increased flow rate of gas. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel cell.

  A fuel cell has a stack structure in which a plurality of types of cell constituent members are stacked to form a minimum unit cell (single cell) and a plurality of cells are stacked. It is ensured. In such a stack structure, a separator, which is a plate-like component, is used as a member that is positioned in the outermost layer of each cell and separates each cell in the stack. The separator has various functions such as a function of supplying fuel gas to the anode side and an oxidizing agent to the cathode side, a function of conducting electricity generated by the cell, and a function of discharging generated water generated in the cell. I'm in charge.

Now, FIG. 10 shows an example of a cell structure of a polymer electrolyte fuel cell. In this cell 10, a membrane / electrode assembly 12 (hereinafter referred to as “MEA”) is disposed at the center of the cell 10 in the thickness direction, and a gas diffusion layer 14 (anode side / cathode) is formed on both surfaces of the cell 10. Side gas diffusion layers 14A, 14C), gas passages 16 (anode side / cathode side gas passages 16A, 16C), and separators 18 (anode side / cathode side separators 18A, 18C), respectively. It has become. There is also an example in which a membrane electrode gas diffusion layer assembly (MEGA) in which the MEA 12 and the gas diffusion layer 14 are integrated is used.
In the structure of the cell 10 in which the gas flow path 16 forms a separate structure from the separator 18 as shown in FIG. 10, for example, an expanded metal is used as a structure forming the gas flow path 16, so that the separator as described above is used. (See, for example, Patent Document 1).

JP 2007-87768 A

By the way, the expanded metal 20 used as a structure forming the gas flow path 16 of the cell 10 has a continuous structure in which a turtle shell-shaped mesh 22 as shown in FIG. This expanded metal 20 is produced by a manufacturing procedure (described later) in which meshes 22 are formed by cutting one step at a time while feeding a flat plate material. ) Forwarding Direction: Hereinafter, also referred to as “FD direction” in this description. ], It has a structure connected in a staircase pattern.
In the cell 10 shown in FIG. 10, the expanded metal 20 is disposed so that the mesh 22 forms an inclined surface between the gas diffusion layer 14 and the separator 18 as shown in FIG. 12. Thus, between the meshes 22 arranged in a staggered manner and the surfaces of the gas diffusion layer 14 and the separator 18, triangular spaces 24 indicated by hatched portions in FIG. 12 are formed in a staggered manner. Therefore, the gas flowing through the gas flow path 16 sequentially flows in the FD direction through the triangular spaces 24 arranged in a staggered manner, and at this time, the gas flow GF is changed to the FD direction as shown in FIG. The direction orthogonal [Transverse Direction or Tool Direction: hereinafter, also referred to as “tool feed direction” or “TD direction”. ], And the flow is such that the turn is repeated.

Therefore, the cross-sectional area of the triangular space 24 indicated by the hatched portion in FIG.
This greatly affects the flow rate of the gas flowing through. However, as described above, when the cells form a stack structure and the expanded metal 20 bites into the gas diffusion layer 14 due to the contact between the gas diffusion layer 14 and the expanded metal 20 at a high surface pressure, FIG. 12 shows. The cross-sectional area of the triangular space 24 will decrease. Due to the reduction in the cross-sectional area of the space 24, the flow rate of the gas flowing through the gas flow path 16 is reduced, leading to a reduction in power generation performance.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a gas flow path in a fuel cell having a cell structure in which a gas flow path is formed by expanded metal disposed between cell constituent members. By enlarging the cross-sectional area of the gas, it is possible to supply gas more uniformly in the gas flow path and improve the power generation performance of the fuel cell.

In order to solve the above problems, a fuel cell of the present invention is a fuel cell having a cell structure in which a gas flow path is formed by expanded metal disposed between cell constituent members, and the gas formed by expanded metal. By diversifying the flow system of the flow path, the cross-sectional area of the gas flow path is increased.
(Aspect of the Invention)
The following aspects of the present invention exemplify the configuration of the present invention, and will be described separately for easy understanding of various configurations of the present invention. Each section does not limit the technical scope of the present invention, and some of the components of each section are replaced, deleted, or further while referring to the best mode for carrying out the invention. Those to which the above components are added can also be included in the technical scope of the present invention.

(1) A fuel cell having a cell structure in which a gas flow path is formed by an expanded metal disposed between cell constituent members, wherein the expanded metal has a large opening and a small alternately in the FD direction and the TD direction. A fuel cell in which an opening is formed.
The fuel cell described in this section has a large opening and a small opening formed in the expanded metal alternately in the FD direction and the TD direction. A variety of gas pathways flowing through both sides are formed. Accordingly, the cross-sectional area of the gas flow path is substantially enlarged, and the gas flow rate is increased.

(2) The fuel cell according to (1), wherein the expanded metal has a large opening and a small opening formed so that phases in the FD direction and the TD direction coincide with each other.
In the fuel cell described in this section, the expanded metal is formed so that the large opening and the small opening are in phase with each other in the FD direction and the TD direction, so that the gas flow is large and small. When the gas flows alternately in the FD direction, the amount of fluctuation of the gas flow in the TD direction is reduced, and an increase in gas pressure loss is avoided to increase the gas flow rate.

(3) In the above items (1) and (2), the strand portion constituting the expanded metal mesh is provided at an intermediate position in the mesh step direction (hereinafter, the step width direction is also referred to as “WD direction”). The fuel cells are connected in a stepped manner in the FD direction by the bonded portions (claim 2).
In the fuel cell described in this section, a strand portion constituting the expanded metal mesh is connected stepwise in the FD direction by a bond portion provided at an intermediate position in the WD direction. The large opening and the small opening are formed alternately in the direction and the TD direction, and the phases in both directions coincide with each other. Both the large opening and the small opening are formed in the gas flow path of the cell. Gas pathways of various systems flowing through are formed. Accordingly, the cross-sectional area of the gas flow path is substantially enlarged, and the gas flow rate is increased.

(4) A fuel cell having a cell structure in which a gas flow path is formed by an expanded metal disposed between cell constituent members, wherein a part of the bond portion of the mesh constituting the expanded metal is divided in the FD direction In addition, a fuel cell in which a small opening different from the large opening formed by the strand portion of the mesh is formed in the bond portion by forming a step in the WD direction (Claim 3).
In the fuel cell described in this section, a part of the bond portion of the mesh constituting the expanded metal is divided in the FD direction and a step is formed in the WD direction, so that the mesh strand portion is formed in the bond portion. A small opening different from the large opening formed is formed, and various types of gas paths flowing through both the large opening and the small opening are formed in the gas flow path of the cell. Accordingly, the cross-sectional area of the gas flow path is substantially enlarged, and the gas flow rate is increased. Moreover, the strand part which a bond part continues in a FD direction is connected reliably, and the intensity | strength of the mesh structure connected in the step shape becomes higher.

(5) The fuel cell according to (1) to (4) above, wherein the small opening is provided in an intermediate portion of the entire thickness of the expanded metal (claim 4).
The fuel cell described in this section is provided with a small opening in the middle part of the full thickness of the expanded metal, but the “full thickness” of the expanded metal is a state where it is arranged between the cell constituent members as described later. Is the thickness of the expanded metal. Therefore, in the fuel cell described in this section, the small opening is located in the middle portion in the thickness direction of the gas flow path constituted by the expanded metal. Therefore, the gas supply to the entire gas channel can be promoted by the gas flow formed in the middle portion in the thickness direction of the gas channel. In addition, even if the gas diffusion layer and other cell components and the expanded metal come into contact with each other at a high surface pressure and the expanded metal bites into the gas diffusion layer, the gas path constituted by the small openings is not limited to the gas diffusion layer or other cells. Since it is not in direct contact with the constituent member, the flow path cross-sectional area does not decrease, and therefore the flow rate of the gas flowing through the small opening located in the middle portion in the thickness direction of the gas flow path does not decrease.

(6) The fuel cell according to (1) to (5), wherein the large opening and the small opening have a similar shape as viewed in the WD direction.
In the fuel cell described in this section, the large opening and the small opening have a similar shape in the WD direction view, and various types of gas paths that flow through both the large opening and the small opening of these similar shapes are formed. Accordingly, the cross-sectional area of the gas flow path is substantially enlarged, and the gas flow rate is increased.

  Since the present invention is configured as described above, in a fuel cell having a cell structure in which a gas flow path is formed by expanded metal disposed between cell constituent members, the cross-sectional area of the gas flow path is increased, By enabling more uniform gas supply in the flow path, the power generation performance of the fuel cell can be improved.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. Detailed description of the same or corresponding parts as those of the prior art will be omitted.
First, in describing the best mode for carrying out the present invention, names of each part of the expanded metal will be clarified in advance with reference to FIG. The expanded metal generally has a so-called staggered arrangement of the turtle shell-shaped mesh 22 described above (see FIGS. 11 and 9C) and the diamond-shaped mesh 26 as shown in FIG. 9A. It has a continuous structure. The crossing portion of the mesh is referred to as a bond portion BO, and the portion connecting the mesh bond portions BO is referred to as a strand portion ST. Further, the length of the bond portion BO in the TD direction is referred to as a bond length BOl, and the thickness of the strand portion ST is referred to as a step width (feed width) W. In the figure, the symbol t is the thickness of the material, and the symbol D is the total thickness of the expanded metal. The total thickness D is the thickness of the expanded metal in a state where it is disposed between the cell constituent members. FIG. 9 also shows the FD direction (material feed direction), TD direction (tool feed direction), and WD direction (mesh width direction).
As is clear from the names of the respective parts, the turtle shell-shaped mesh 22 has a long mesh shape with a bond length BO1 of the bond portion BO, and the diamond-shaped mesh 26 has a short mesh shape with a bond length BO1 of the bond portion BO. . And since the FD direction cross-sectional shape (AA cross-sectional shape) of the rhombus mesh 26 and the FD cross-sectional shape (A'-A 'cross-sectional view) of the turtle shell-shaped mesh 22 are the same, FIG. The cross-sectional shape of both of them in the FD direction is shown in b).

  In the cell fuel cell according to the embodiment of the present invention, an expanded metal is used as a gas flow path forming member, and this expanded metal has a structural structure as schematically shown in FIGS. It has features. That is, the strand part ST which comprises the mesh of the expanded metal 28 is connected to the expanded metal 28 stepwise in the FD direction by the bond part BO provided at the intermediate position in the WD direction. The large openings 30 and the small openings 32 are formed alternately and in such a manner that the phases in both directions coincide with each other. Further, the small opening 32 is provided at an intermediate portion of the full thickness W of the expanded metal 28. And in the example of illustration, the large opening 30 and the small opening 32 have comprised the similar shape of the turtle shell shape by the WD direction view of a mesh.

Here, the manufacturing procedure of the expanded metal 28 according to the embodiment of the present invention will be described with reference to FIGS.
A mold for manufacturing the expanded metal 28 includes a die 34 including a die 34, a pad 36, a lower blade 38, and an upper blade 40 shown in FIGS. The lower blade 38 and the upper blade 40 are both shifted in the TD direction (direction orthogonal to the FD direction) and moved up and down in the WD direction (up and down direction). Further, trapezoidal protrusions 40a are formed on the lower surface of the upper blade 40 at regular intervals in the TD direction, and the upper surface of the lower blade 38 is also fixed so as to mesh with the trapezoidal protrusion 40a of the upper blade 40. A trapezoidal protrusion 38a is formed at an interval.

The flat plate material 42 is fed into the mold with a predetermined step width W by a material feeding means having a roller or the like, and the flat plate material 42 can pass through the pad 36 in accordance with the feeding timing of the flat plate material 42. Ascend and descend in the WD direction. 5A and 5B, the upper blade 40 and the lower blade 38 open and close in a state where the flat plate material 42 is sandwiched between the die 34 and the pad 36, and the trapezoidal shape of the upper blade 40 is obtained. Due to the protrusions 40a and the die 34, the flat plate material 42 is partially sheared at regular intervals to form trapezoidal cuts protruding downward. At the same time, the flat plate material 42 is partially sheared at regular intervals by the trapezoidal protrusion 38 a of the lower blade 38 and the pad 36, and is formed by the trapezoidal protrusion 40 a of the upper blade 40 and the die 34. Alternatingly with the downward projections, trapezoidal cuts protruding upward are formed, and the mesh is formed together with the trapezoidal cuts protruding downward.
Incidentally, FIG. 2, as shown in FIG. 5 (b), the depth _{CD 40} cut by the upper blade 40, by giving a difference to the depth _{CD 38} cut by the lower blade 38, the lath cut metal 28 ' A large opening 30 and a small opening 32 that are similar to each other are formed. Incidentally, the depth CD ₄₀ cut by the upper blade 40, the magnitude relationship between the depth CD ₃₈ cut by the lower blade 38, one of them may be those larger than the other.

Each time the upper blade 40 and the lower blade 38 are raised, the upper blade 40 and the lower blade 38 are shifted in the TD direction so that trapezoidal cuts are formed step by step in a staggered manner, and have a stepped mesh. Lascut metal 28 'is formed.
Thereafter, the lath-cut metal 28 ′ having a stepped mesh is rolled by the rolling roller 43 shown in FIG. 4, thereby forming the expanded metal 28 having a necessary full thickness D (see FIG. 9B). .

According to the embodiment of the present invention configured as described above, the following operational effects can be obtained.
That is, as shown in FIG. 1 and FIG. 2, the strand part ST constituting the mesh of the expanded metal 28 is connected stepwise in the FD direction by the bond part BO provided at the intermediate position in the WD direction. In the expanded metal 28, large openings 30 and small openings 32 are formed alternately in the FD direction and the TD direction. Then, as shown in FIGS. 1 and 2, only the triangular space 24 formed by the large opening 30 is passed through the gas flow path 16 of the cell 10 constituted by the expanded metal 28 in turn. Various types of gas paths such as the gas flow GF ₁ flowing through both the large opening 30 and the small opening 32 as well as the gas flow GF _{0 in the} repeated mode (same as the conventional one) are formed. Therefore, the flow passage cross-sectional area of the gas flow passage 16 is substantially enlarged, and the gas flow rate is increased.
In addition, since the large opening 30 and the small opening 32 are formed in the expanded metal 28 so that the phases in the FD direction and the TD direction coincide with each other, the gas flow GF has a large opening 30 and a small opening 32. When the gas flows alternately in the FD direction, the amount of fluctuation of the gas flow in the TD direction decreases, and an increase in gas pressure loss is avoided to increase the gas flow rate. Therefore, more uniform gas supply is possible in the gas flow path 16 of the cell 10, and the power generation performance of the fuel cell can be improved.

  Further, a small opening 28 is provided in the middle portion of the entire thickness W of the expanded metal 28, and the small opening 28 is located in the middle portion in the thickness direction of the gas flow path 16 constituted by the expanded metal 28 of the cell 10. . Therefore, the gas supply to the entire gas channel 16 can be promoted by the gas flow GF (see FIG. 2) formed in the middle portion in the thickness direction of the gas channel. Even if the gas diffusion layer 14 and other cell constituent members are in contact with the expanded metal 28 at a high surface pressure, and the expanded metal 28 bites into the gas diffusion layer 14, the gas path constituted by the small openings 32 Since the diffusion layer 14 and other cell constituent members are not in direct contact with each other, there is no reduction in the cross-sectional area of the flow path. The flow rate does not decrease. Therefore, the power generation performance of the fuel cell can be improved by avoiding an increase in gas pressure loss.

Further, in the manufacturing process of the expanded metal 28 according to the embodiment of the present invention, the cut depth CD ₄₀ by the upper blade 40 is different from the cut depth CD ₃₈ by the lower blade 38, so that the lath cut metal 28 ' In addition, due to the formation of the large opening 30 and the small opening 32 that are similar to each other, the large opening 30 and the small opening 32 form a similar shape (tortoise shape) in the WD direction view. . Various types of gas paths that flow through both the large opening 30 and the small opening 32 having similar shapes are formed. Accordingly, the cross-sectional area of the gas flow path is substantially enlarged, and the gas flow rate is increased.

  Note that, as shown in FIG. 6, the expanded metal 128 as a member for forming the gas flow path 16 of the cell 10 can be configured with a diamond-shaped mesh 44. Also in this case, the strand part ST constituting the diamond-shaped mesh 44 of the expanded metal 128 is connected stepwise in the FD feed direction by the bond part BO provided at the intermediate position in the WD direction. Are formed in such a manner that rhombus large openings 46 and small openings 48 are alternately arranged in the FD direction and the TD direction, and the phases in both directions coincide with each other. Also in this case, since the manufacturing procedure of the expanded metal 128 is the same as the example of the turtle shell-shaped mesh 22 in FIGS. 1 and 2, the small opening 48 is provided in the middle portion of the full thickness W of the expanded metal 128. The large opening 46 and the small opening 48 are similar to a rhombus when viewed in the WD direction of the mesh.

Further, an expanded metal 228 having a structure as shown in FIG. 7 can be used as a member for forming the gas flow path 16 of the cell 10. That is, in the expanded metal 228 of FIG. 7, a part of the bond portion BO constituting the mesh 50 is divided in the FD direction and a step is formed in the WD direction as compared with the conventional expanded metal (FIG. 11). Thus, a small opening 5 different from the large opening 52 formed by the strand part ST of the mesh is formed in the bond part BO.
4 is formed. And bond part BO (in this case, the bond part which remains clearly) will connect the strand parts ST which continue in FD direction reliably, and the intensity | strength of the mesh structure connected in step shape will improve more. .

Also in this case, since the manufacturing procedure of the expanded metal 228 is the same as the example of the turtle shell-shaped mesh 22 in FIGS. 1 and 2, the small opening 54 is formed at the middle portion of the total thickness W of the expanded metal 128. Is provided. On the other hand, in the example of FIG. 7, the large opening 52 is a 14-square shape, and the small opening 54 is a turtle shell shape, and they are not similar. The shapes of the large opening 52 and the small opening 54 are, as shown in FIG. 8, a multistage trapezoidal protrusion 58a formed on the lower surface of the upper blade 58 of the mold for manufacturing the expanded metal 28, This is determined by the shape of the multi-step trapezoidal protrusion 56 a formed on the upper surface of the lower blade 56. Further, the shapes of the lower blade 56 and the upper blade 58 shown in FIG. 8 are merely examples, and other shapes can be used as long as they can form a mesh shape in which the bond portion BO clearly remains. May be.
In addition, about the structure of manufacturing apparatuses, such as the die | dye 34 and the pad 36, it is the same as that of the example of FIG. 1, FIG. Further, description of the effects of the example of FIGS. 1 and 2 is omitted.

  Note that the expanded metals 28, 128, 228 according to the embodiment of the present invention may be used for any of the anode-side / cathode-side gas flow paths 16A, 16C, and only on one side where pressure loss is to be suppressed. Can also be used. Further, the expanded metals 28, 128, and 228 according to the embodiment of the present invention can also be used in a cell that does not include one or both of the anode-side / cathode-side gas diffusion layers 14A and 14C.

It is a three-dimensional view of an expanded metal that is a gas flow path forming member of the fuel cell according to the embodiment of the present invention. The expanded metal BB cross section shown in FIG. 1 is indicated by a solid line, and the CC cross section is indicated by a dotted line. It is the perspective view which showed typically the metal mold | die which comprises the manufacturing apparatus of the expanded metal which concerns on embodiment of this invention. It is the side view which showed roughly the rolling roller which comprises the manufacturing apparatus of the expanded metal which concerns on embodiment of this invention. The operation state of the metal mold | die which comprises the manufacturing apparatus of the expanded metal which concerns on embodiment of this invention is shown, (a) shows the side view of each operation state, (b) shows the front view of each operation state. ing. It is a three-dimensional view concerning the example of application of the expanded metal which is the formation member of the gas channel of the fuel cell concerning an embodiment of the invention. FIG. 6 is a three-dimensional view of still another application example of an expanded metal that is a gas flow path forming member of the fuel cell according to the embodiment of the present invention. It is a front view of the metal mold | die which comprises the manufacturing apparatus of the expanded metal which concerns on FIG. It is explanatory drawing of each part name of an expanded metal, (a) is a top view of a rhombus mesh, (b) is sectional drawing in AA and A'-A 'line, (c) is a plane of a turtle shell shape mesh FIG. It is sectional drawing which shows an example of the cell structure of the conventional polymer electrolyte fuel cell. It is the figure which looked at the expanded metal provided with the turtle shell-shaped mesh which forms the gas flow path of the cell shown by FIG. 10 in the step width direction of the mesh. It is sectional drawing of the gas flow path of the conventional cell using the expanded metal shown by FIG.

Explanation of symbols

10: Cell, 12: MEA, 14, 14A, 14C: Gas diffusion layer, 16, 16A, 16C: Gas flow path, 18, 18A, 18C: Separator, 22: Tortoise mesh, 24: Space, 28, 128 228: expanded metal, 30: large opening, 32: small opening, 34: die, 36: pad, 38, 56: lower blade, 38a, 40a: trapezoidal protrusion,
40, 58: Upper blade, 42: Flat plate material, 56a, 58a: Multistage trapezoidal protrusion

Claims (5)

A fuel cell having a cell structure in which a gas flow path is formed by an expanded metal disposed between cell constituent members,
The expanded metal has a large opening and a small opening formed alternately in a material feeding direction and a tool feeding direction so that the phases in both directions coincide with each other. A fuel cell having a cell structure in which a gas flow path is formed by an expanded metal disposed between cell constituent members,
The strand portion constituting the expanded metal mesh is connected in a stepwise manner in the material feed direction by a bond portion provided at an intermediate position in the mesh cut direction, so that the expanded metal has a material feed direction and a tool feed. A fuel cell characterized in that a large opening and a small opening are formed alternately in directions and in such a manner that the phases of both directions coincide with each other. A fuel cell having a cell structure in which a gas flow path is formed by an expanded metal disposed between cell constituent members,
A part of the bond part of the mesh constituting the expanded metal is divided in the material feeding direction, and a step is formed in the step width direction, so that the bond part is formed by a mesh strand part. A fuel cell, wherein a small opening different from the opening is formed. The fuel cell according to any one of claims 1 to 3, wherein the small opening is provided in an intermediate portion of the entire thickness of the expanded metal. The fuel cell according to any one of claims 1 to 4, wherein the large opening and the small opening have a similar shape when viewed in a mesh step width direction.