JP2007234389A - Fuel cell and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell in which a pressure loss in a gas passage is made small when it is large. <P>SOLUTION: A plurality of sealing parts are provided beforehand in a connection part of a manifold 12 with the gas passage 16 in a cell, and when a pressure loss in the gas passage is large, a penetrating mouth 22 is provided on the separator 10 near the manifold 12. As a result, the gas passage 16 is connected to the manifold 12 and the pressure loss in the gas passage can be reduced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel cell formed by sandwiching a membrane electrode assembly (MEA) by a pair of separators, and in particular, to a connection structure between a gas channel in the cell and a manifold that is a gas channel outside the cell.

  Conventionally, a fuel cell is known as a highly efficient and clean energy source. In this fuel cell, a unit cell is formed by sandwiching both sides of a membrane electrode assembly (MEA) in which a solid polymer membrane is used as an electrolyte membrane and an anode side diffusion layer and a cathode side diffusion layer are formed on both sides of the membrane electrode assembly. A desired output is obtained by laminating a large number.

  When a large number of fuel cells are used in this way, it is preferable that these fuel cells have the same capacity as much as possible. Therefore, usually, each fuel cell is inspected and only proper ones are adopted.

JP 2004-342596 A

  Here, some fuel cells have high pressure loss in the gas flow path. That is, in the fuel cell, there is a cell in which the gas from the outside flows through the anode gas diffusion layer and the cathode gas diffusion layer, but the resistance at the time of the gas distribution increases.

  The gas is circulated to the gas diffusion layer from the supply side manifold through the in-cell gas flow path formed as a concave groove in the separator, and reaches the discharge side manifold through the in-cell gas flow path. Here, when the shape of the separator is different or the thickness of the MEA is different, the pressure loss in the gas flow changes. In addition, when forming a cell in which a pair of separators are bonded while sandwiching the MEA, if the adhesive protrudes from the flow path, the gas flow path is blocked, and the pressure loss (pressure loss) of the gas flow changes.

  In particular, since the fuel cell is formed by adhesion, it cannot be disassembled and repaired thereafter, and the defective product can only be discarded.

  The present invention provides a technique for reducing the pressure loss of a cell having a high pressure loss.

  The present invention is a fuel battery cell formed by sandwiching a membrane electrode assembly (MEA) by a pair of separators, and the separator has an in-cell gas flow path for flowing gas into the cells. A plurality of grooves are formed, and a manifold which is an out-cell gas flow path is formed as a hole at the end of the separator, and the vicinity of the connection portion between the plurality of in-cell gas flow paths and the manifold is formed by a sealing plate. The grooves of the plurality of in-cell gas flow paths are covered, and a part of the connection portion between the plurality of in-cell gas flow paths and the manifold has a sealing portion between the in-cell gas flow paths and the manifold. It is sealed.

  Further, according to the present invention, in the fuel cell, when the pressure loss when the gas flows between the in-cell gas flow path and the manifold is large, the in-cell gas provided with the sealing portion A hole is formed in the separator at a connection portion between the flow path and the manifold, and the in-cell gas flow path and the manifold are communicated with each other via an external space of the separator.

  According to the present invention, when the gas flow resistance of the manufactured cell is large, the in-cell gas flow path sealed by the sealing portion is connected to the manifold via the communication port provided in the separator 10. This reduces the pressure loss and makes the cell usable.

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

  FIG. 1A is a plan view of a main part of the separator 10 as viewed from the outside of the cell, and FIG. 1B is a cross-sectional view of a portion close to the manifold 12.

  An oblong hole is formed in a portion near the corner of the separator 10, and this is a manifold 12. That is, when the manifold 12 is formed and laminated at the same position on the separator 10 constituting the cell, the manifold 12 continuously becomes a gas flow path.

  A gasket 14 is arranged around the manifold 12 on the outer surface of the separator 10 so as to surround the manifold 12. Therefore, the inner periphery of the gasket 14 becomes a seal line, and the inside thereof is a space communicating with the manifold 12.

  Further, an in-cell gas flow path 16 is formed as a concave groove on the inner surface of the separator 10. The in-cell gas flow path 16 is covered with a sealing plate 18. Further, at least one of the plurality of in-cell gas flow paths 16 (two of the five in the drawing) is formed with a sealing portion 20 and is disconnected from the manifold 12.

  If, for some reason, the pressure loss of the gas flow path is large, the separator 10 on the manifold side of the sealing line of the in-cell gas flow path 16 in which the sealing portion 20 is formed is formed in the through-hole 22 as shown in FIG. Open. For example, the through hole 22 is opened from the outside of the cell with a drill or the like. As a result, the in-cell gas flow path 16 communicates with the outer space of the cell through the through-hole 22. This outer space is on the manifold 12 side of the sealing line, and the in-cell gas flow path 16 is connected to the manifold 12 by the through-hole 22.

  FIG. 3 shows a cross-sectional view of the vicinity of the manifold 12 when two cells are stacked. The fuel battery cell 30 is formed by bonding two separators 10 together. The two separators 10 are connected by an adhesive 32 at the peripheral part, and the inside functions as a battery cell. On the inner side, the MEA 40 is disposed in which the anode side gas diffusion layer 40a and the cathode side gas diffusion layer 40c are stacked with the electrolyte membrane 40b interposed therebetween. Note that only the electrolyte membrane 40b extends at the end of the MEA 40, and the electrolyte membrane 40b is sandwiched and fixed between the pair of separators 10. Further, a large number of concave grooves are formed on the cell inner side of the separator 10 to form a gas flow path, and the MEA 40 is supported at a portion corresponding to the bank of the groove.

  In FIG. 3, the lower side of the MEA 40 is the anode side gas diffusion layer 40a, and the manifold 12 communicates with the in-cell gas flow path 16 on the anode side. However, in the upper fuel cell 30 of FIG. A sealing portion 20 is formed, and the connection between the in-cell gas flow path 16 on the anode side and the manifold 12 is disconnected by the sealing portion 20. For example, when eight in-cell gas flow paths 6 are provided, about two in-cell gas flow paths 16 provided with the sealing portion 20 are provided. For most of the cells 30, the six in-cell gas flow paths 16 are connected to the manifold 12, resulting in a predetermined pressure loss, and no work needs to be performed. However, some of the pressure loss increases for some reason. Only such a cell is processed to open the through hole 22.

  On the other hand, in the upper cell of FIG. 3, a through-hole 22 is formed in the anode-side separator 10 on the manifold 12 side from the gasket 14. Therefore, the in-cell gas flow path 16 on the anode side is connected to the manifold 12 via the through hole 22 and the outer space of the separator 10. That is, the in-cell gas flow path 16 is connected to the manifold 12 by providing the through-hole 22 in the separator 10 on the manifold 12 side from the sealing line of the in-cell gas flow path 16 sealed by the sealing portion 20. And the number of gas flow paths increases. Therefore, the pressure loss about the gas flow path of the cell can be reduced, and the cell having a large pressure loss can be used as a defective product without being discarded.

  FIG. 4 shows an example in which the through-hole 22 is provided in the in-cell gas flow path 16 on the cathode side. Similarly to the example of FIG. 3, in this example, by providing the through-hole 22 in the separator 10 on the manifold 12 side from the sealing line of the in-cell gas flow path 16 sealed by the sealing portion 20, the in-cell gas flow path 16 is connected to the manifold 12.

  As described above, according to the present embodiment, the manufactured fuel battery cell 30 is inspected for gas flow resistance, and when the resistance is equal to or greater than a predetermined value (pressure loss is equal to or greater than a predetermined value), the fuel cell 30 is sealed by the sealing unit 20. Through holes 22 are provided in the separator 10 on the manifold 12 side from the sealing line of the in-cell gas flow path 16. As a result, the pressure loss is reduced and the fuel cell 30 can be used.

  In a normal case, the pressure loss of the manufactured fuel battery cell 30 is distributed in a substantially normal distribution as shown in FIG. And by performing the above-mentioned process about the inferior goods whose pressure loss is more than predetermined, these can be utilized as good goods.

It is a figure which shows the plane and cross-sectional structure of a manifold vicinity. It is a figure which shows formation of a through-hole. It is sectional drawing explaining the connection of the gas path in an anode side cell, and a manifold. It is sectional drawing explaining the connection of the gas path in a cathode side cell, and a manifold. It is a figure which shows distribution of the pressure loss of a cell.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Separator, 12 Manifold, 14 Gasket, 16 Gas flow path in cell, 18 Sealing plate, 20 Sealing part, 22 Through-hole, 30 Fuel cell, 32 Adhesive, 40 MEA, 40a Anode side gas diffusion layer, 40b Electrolyte Membrane, 40c Cathode side gas diffusion layer.

Claims (2)

A fuel cell formed by sandwiching a membrane electrode assembly (MEA) by a pair of separators,
In the separator, a plurality of in-cell gas flow paths for circulating gas in the cell are formed as concave grooves, and a manifold that is a gas flow path outside the cell is formed as a hole at the end of the separator,
The vicinity of the connection portion between the plurality of in-cell gas flow paths and the manifold is covered with a groove in the plurality of in-cell gas flow paths by a sealing plate,
The connection between the plurality of in-cell gas flow paths and the manifold is sealed between the in-cell gas flow paths and the manifold by a sealing portion.
The fuel cell characterized by the above-mentioned. 2. The fuel cell according to claim 1, wherein when the pressure loss when the gas flows between the in-cell gas flow path and the manifold is large, the in-cell gas flow path provided with the sealing portion; A method of manufacturing a fuel cell, comprising: forming a hole in a separator at a connecting portion of the manifold, and communicating a gas flow path in the cell and the manifold via an external space of the separator.

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