JP5061714B2 - Gas flow path forming member for fuel cell and fuel cell - Google Patents

Description

  The present invention relates to a gas flow path forming member of a fuel cell that forms a gas flow path for circulating a reaction gas in a fuel cell, and a fuel cell using the same.

  Conventionally, various proposals have been made on fuel cells. A fuel cell is usually configured by laminating a plurality of battery cells, and one battery cell is composed of a pair of separators disposed on both sides of a membrane electrode assembly (MEA) via gas flow paths. In such a fuel cell, it is important to effectively distribute gas, and there are proposals of Patent Documents 1 and 2, for example, regarding the configuration of the gas flow path.

  In patent document 1, what formed streak-like unevenness | corrugation about the expanded metal obtained by rolling a lath cut metal on the plane is arrange | positioned as a gas flow path formation member between a gas flow path separator and MEA.

  Further, in the cited document 2, it is shown that a lath cut metal formed into a corrugated shape by a corrugated molding machine is used as a gas flow path forming member.

JP 2005-310633 A JP 2007-26812 A

  Such a gas flow path forming member is required to supply gas as uniformly as possible to the entire MEA. Further, since water generated by the battery reaction is generated on the cathode side of the battery cell, it is desired that this water can be effectively discharged.

  The present invention relates to a gas flow path forming member for a fuel cell that forms a gas flow path for allowing a reaction gas to flow in a fuel battery cell, wherein the plate material is discretely cut to leave a beam portion. The lath-cut metal having a plurality of openings formed in the shape is used, and the beam portion is moved up and down in the lateral direction to be cut at the same time, and repeats the mountain and valley portions, and one of the top portion of the mountain portion or the bottom portion of the valley portion is the other. The crests and troughs that form a longitudinally adjacent opening perpendicular to the cutting direction are partially connected at the same time, so that the opening is tapered upwards. The upper trapezoidal portion and a lower trapezoidal portion that tapers downward are characterized in that the upper trapezoidal portion and the lower trapezoidal portion have different sizes.

Further, the upper trapezoidal portion is the same size in the transverse direction, the lower trapezoidal portion, in the transverse direction, it is preferable that the same is the size.

  The present invention also provides a fuel cell that uses the gas flow path forming member of the fuel cell described above, and the fuel battery cell is configured by providing a pair of separators on both sides of the battery reaction member via the gas flow path. The gas flow path forming member of the fuel cell is disposed in the gas flow path on the cathode side of the gas flow path.

Also, among the gas flow path, arranged gas flow path forming member of a fuel cell according to claim 1 to the outlet side of the gas passage of mosquitoes cathode side, the inlet side of the cathode side of the gas flow path, It is preferable to arrange the gas flow path forming members having the same size of the upper trapezoidal portion and the lower trapezoidal portion.

  According to the present invention, since the gas flow path forming member has an irregularly shaped Lascut metal, the area that contacts the separator when placed in the battery cell can be reduced, and the amount of water collected in the contact portion Can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a configuration of a battery cell. A gas flow path forming member 12 is disposed on both sides of a MEGA (membrane electrode gas diffusion layer assembly) 10 having diffusion layers formed on both sides of the MEA (membrane electrode assembly), and a separator 14 is disposed outside thereof. ing. Further, the gas flow path forming member 12 has a smaller area than the MEGA 10 and the separator 14, and the gas flow path in which the gas flow path forming member 12 is disposed is sealed by sealing the MEGA 10 and the peripheral portion of the pair of separators 14 with the sealing material 16. The road is sealed in a sealed state.

  Then, air (oxygen-containing gas) is circulated as an oxidant gas in the cathode-side gas flow path, and hydrogen gas (hydrogen-containing gas) is supplied as a fuel gas to the anode-side gas flow path. The generated electric power is obtained between the pair of electrodes. The gas flow path forming member 12 is formed of a metal such as stainless steel, and this also functions as a current collecting member. Usually, a large number of such battery cells are stacked, and battery output is obtained from both ends thereof.

  2 and 3 show a configuration of the gas flow path forming member 12 according to the embodiment. FIG. 2 shows the configuration of the region on the inlet side of the oxidant gas, and FIG. 3 shows the configuration of the gas flow path forming member 12 in the region on the outlet side of the oxidant gas.

  The gas flow path forming member 12 is formed of a lath cut metal. That is, by cutting the metal plate material discretely in a zigzag pattern, a plurality of hexagonal openings are formed in a zigzag pattern leaving the beams to be connected as shown in FIG. The top of each hexagonal opening forms the bottom of the top opening and serves as a beam connection.

  In the example of FIG. 2, the hexagons of the openings are substantially regular hexagons, and the openings in the figure are arranged in a honey comb shape, and the lengths of the tops and the bottoms of the openings are the same.

  On the other hand, in FIG. 3, the opening is not a regular hexagon but an irregular shape. That is, the opening has a shape in which an upward trapezoid and a downward trapezoid are connected, but the upper trapezoid is small and the lower trapezoid is large. Therefore, the top of the upper trapezoid is connected to only a part of the bottom of the upper opening. In other words, as shown in the figure, in the view B viewed from the B direction, the connecting portion is shorter in FIG. 3 than the structure in FIG. 2.

  In the case of the structure of FIG. 3, only the top (long side) of the opening is in contact with the opposing surface on one side of the gas flow path forming member 12, and only the bottom (short side) of the opening is on the other side. Contact the opposite surface. That is, in the structure of FIG. 3, by covering the separator 14 from above the paper surface, the surface of the beam portion is inclined with respect to the separator 14, and only the tip of the short side on the front side contacts the separator 14. . The gas flow is basically in the vertical direction in the figure.

  FIG. 4 shows the configuration of the gas flow path forming member 12 and the separator 14 inside the battery cell. As described above, the separator 14 is provided with the inlet of the oxidizing gas (three in this example) on the upper side, and the outlet of the oxidizing gas (three in this example) is provided on the lower side. . These inlets and outlets are configured as manifolds penetrating the separators 14 of the plurality of battery cells, and the manifolds and gas passages communicate with each other through a number of passages provided in the separators 14.

  Therefore, in FIG. 4, the gas flowing in from the oxidant gas inlet passes through the gas flow path forming member 12 and flows downward, and is discharged from the oxidant gas outlet. A fuel gas (hydrogen gas) is supplied to the gas flow path on the opposite side of the MEGA 10. For example, the manifold for the inlet and outlet of the fuel gas is arranged in a portion without the manifold for the oxidant gas, and similarly, the fuel gas flows through the gas flow path from the inlet side to the outlet side.

  In the present embodiment, the gas flow path forming member 12 of FIG. 2 is used on the inlet side of the oxidant gas flow path, and the gas flow path forming member 12 of FIG. 3 is used on the outlet side. As a result, on the inlet side, the gas is circulated by using an all hexagonal opening which is an opening having a low resistance to the gas flow.

  On the other hand, on the outlet side, the opening itself has an irregular shape, but the contact portion with the separator 14 is small. Thereby, the amount of water accumulated in the contact portion between the gas flow path forming member 12 and the separator 14 can be reduced.

  That is, as shown in FIG. 5, in the oxidant gas flow path, the flow toward the gas outlet hits the contact portion between the gas flow path forming member 12 and the separator 14, and water tends to accumulate here. As shown in FIG. 6A, when the area of the contact portion is large, the amount of water accumulated in the contact portion increases accordingly. In this embodiment, as shown in FIG. 6B, since the area of the contact portion is small, the amount of water accumulated here can be reduced.

  Since the portion where water has accumulated cannot function as a fuel cell, the effective area of the battery can be increased by reducing the amount of accumulated water, and water can be effectively discharged from the cell. Moreover, since it inclines to the separator 14 side, it is hard for water to collect on the MEGA10 side, and a battery reaction is hard to be inhibited.

  The ratio of the configuration of FIG. 2 on the inlet side and the configuration of FIG. 3 on the outlet side can be arbitrarily set, but it is preferable to form at least about 10% of the configuration of the configuration of FIG. However, it may be 100% (all configurations on the outlet side in FIG. 3).

  Moreover, although the oxidant gas distribution side has been described, it is preferable to adopt the same configuration on the fuel gas distribution side. In consideration of water discharge, it is preferable that the gas outlet is positioned below. However, since water is accompanied by the flow of gas, the gas may flow in the horizontal direction.

It is sectional drawing of a battery cell. It is a figure which shows the structural example of a gas flow path formation member. It is a figure which shows the structural example of a gas flow path formation member. It is a figure which shows the structure of a separator and a gas flow path formation member. It is a figure which shows the state of the water which accumulates on a gas flow path formation member. It is a figure which shows the state of the water which accumulates on a gas flow path formation member.

Explanation of symbols

  10 MEGA, 12 gas flow path forming member, 14 separator, 16 sealing material.

Claims (4)

A fuel cell gas flow path forming member that forms a gas flow path for circulating a reaction gas in a fuel cell,
While using a lath cut metal that cuts the plate material discretely and forms a plurality of openings in a staggered manner while leaving the beam part,
The beam part rises and falls in the horizontal direction to be cut simultaneously and repeats the peak and valley parts, and one of the top part of the peak part or the bottom part of the valley part is longer than the other, and the vertical part perpendicular to the direction to be cut simultaneously. The crests and troughs that form openings adjacent in the direction are partially connected,
Accordingly, the opening is composed of an upper trapezoidal portion that tapers upward and a lower trapezoidal portion that tapers downward, and the sizes of the upper trapezoidal portion and the lower trapezoidal portion are different. A gas flow path forming member for a fuel cell. The gas flow path forming member according to claim 1,
The upper trapezoidal portion is the same size in the transverse direction, the lower trapezoidal portion, in the transverse direction, the fuel cell of the gas flow path forming member, characterized in that the same is the size. A fuel cell using the gas flow path forming member of the fuel cell according to claim 1 or 2,
The fuel battery cell is configured by providing a pair of separators on both sides of the battery reaction member via a gas flow path,
A fuel cell comprising: a gas flow path forming member for a fuel cell according to claim 1 or 2 disposed in a gas flow path on a cathode side of the gas flow path. A fuel cell using the gas flow path forming member of the fuel cell according to claim 1 ,
Wherein one of the gas flow path, the gas flow path forming member of a fuel cell according to claim 1 to the outlet side of the gas passage of mosquitoes cathode side are arranged, on the inlet side of the cathode side of the gas flow path, the upper trapezoid A fuel cell comprising a gas flow path forming member having the same size as the lower trapezoidal portion.

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