JP2000077083A - Fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To save time and labor and to reduce production cost by dispensing with a resin impregnation process and making a cell thin. SOLUTION: A channel 2-3 is formed by advancing zigzag in the surface direction a hole perforated from the face to the back in a sheet member to form channel bodies 2, 8. The channel bodies 2, 8 having the channel 2-3 capable of supplying the same flow rate as the conventional channel body having a groove formed on the surface of a plate material can be made thin. Therefore, a fuel cell can also be made thin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell, and more particularly to an improvement in a flow path constituting portion thereof.

[0002]

2. Description of the Related Art A fuel cell is a battery in which a fuel gas and an oxidizing gas are respectively passed over an electrode surface and an electromotive force is obtained by a reaction at the electrode surface. Therefore, fuel cells include
A flow path component is provided for allowing the flow of these reaction gases or discharging the substances (water, carbon dioxide gas, etc.) generated by the above reaction.

FIG. 4 is a diagram showing a laminated structure of a main part of a fuel cell. 20 is a separator, 21 is a flow path component, 22
Is an electrode portion (anode side), 23 is an electrolyte membrane, 24 is an electrode portion (cathode side), 25 is a flow path component, 26 is a separator, and K is a battery component half. Electrode portions 22 and 24 are provided with an electrolyte membrane 23 interposed therebetween, and flow path forming portions 21 and 25 are stacked outside the electrode portions 22 and 24. This constitutes one unit (unit cell) of the fuel cell. Separator 20, 2
Reference numeral 6 is for partitioning from other unit cells. As can be seen from this figure, the structure is symmetrically stacked around the electrolyte membrane 23. For convenience of description, the portion named the battery component half K is a portion corresponding to half of the unit cell.

FIG. 5 is an exploded view of a conventional fuel cell. The reference numerals correspond to those in FIG. 4, 24A is an electrode, 24B is a gasket, 24C is an opening, 26-1.
Is a through hole. The electrode portion 24 includes an electrode 24A and a gasket 24B, and the electrode 24A is
4B is fitted into the central opening 24C. The separator 26 is provided with a through hole 26-1 through which gas is supplied to or discharged from the flow path constituting unit 25. FIG. 5 shows the configuration of the lower half of FIG. 4, but the same applies to the configuration of the upper half.

FIG. 6 is a view for explaining an example of a conventional flow path constituting section 25. As shown in FIG. In FIG. 6, reference numeral 30 denotes a channel body, and 301
Is a projection (flow path wall), 302 is a depression (flow path), 31 is a frame, 311 is a step, 312 is a through hole, and 313 is an opening. The flow path component 25 includes a frame 31 and a flow path 30. The flow path 30 is fitted into the opening 313 of the frame 31.

[0006] On the surface of the channel body 30 facing the electrode,
A plurality of linear projections 301 and depressions 30 in the same direction
2 are provided. The convex portion 301 forms a channel wall, and the concave portion 302 forms a gas channel. When the channel body 30 is fitted into the central opening 313 of the frame body 31, the opening 3
A step 311 is provided along the sides on the starting end side and the ending side of the convex portion 301 among the inner sides of the projection 13. The height of the step 311 is the same as the height of the bottom of the recess 302. Thereby, when the flow path body 30 is fitted, the step 311 also forms a part of the flow path. The step 311 is provided with a through hole 312 for supplying gas.

FIG. 7 is a plan view of a conventional flow path forming section 25. That is, it is a plan view of the channel body 30 fitted in the frame body 31, and the reference numerals correspond to those in FIG. The gas flows as indicated by the arrows. By the way, the flow path component 2
5 is required to have electrical conductivity and corrosion resistance, so that carbon is usually used. That is, the channel body 30 is also made of carbon.

As a method for forming the linear convex portions 301 and concave portions 302 on the carbon plate material, a method using NC processing or a method using a grindstone device is adopted. In the NC processing, as is well known, numerical values are set in an NC device (numerical control device) so as to cut a desired shape (in this case, linear convex portions and concave portions), and one convex portion and concave portion are formed. I will cut one. In the method using a grindstone device, a plurality of convex portions and concave portions are simultaneously cut by a plurality of grindstones prepared according to the convex portions and concave portions to be formed.

In the above, a plurality of grooves having open ends are formed in parallel on one side of a plate-like material, and the grooves are fitted into another frame provided with a through hole as an entrance for fuel or the like. In some cases, the separator is specially processed in order to use the separator member also as a flow path body in order to reduce the thickness.
That is, a groove is formed by machining or the like on one side of the central portion of the member, and the peripheral portion (portion where gas is not desired to pass) is impregnated with resin and subjected to gas sealing. Some of them are disclosed in, for example,
No. 3).

[0010]

However, the above-mentioned conventional fuel cell has the following problems with respect to the flow path constituting portion. Since a groove is formed in the surface of the plate material to form a flow path, if the plate material is made thinner in order to reduce the thickness of the fuel cell, it becomes difficult to form the groove, and there has been a limit in making the fuel cell thinner. In the case where the separator is also used, there is a step of impregnating the resin, which increases the number of working steps and increases the processing cost. An object of the present invention is to solve the above problems.

[0011]

According to the present invention, there is provided a first flow path, a first gasket, a first electrode, an electrolyte membrane, a second electrode, a second gasket, In a fuel cell obtained by stacking unit cells in which a second flow path body is stacked in this order, with a separator interposed therebetween, the first and second flow path bodies are formed using a sheet-like member as a member thereof, It is assumed that the separator has a flow path formed by advancing in a zigzag manner in a plane direction from a front surface of the shaped member to a back surface, and is laminated with the first and second flow path bodies of the separator. Occasionally, a through hole for allowing gas to flow is formed at a position corresponding to the start end and the end of the flow path.

(Summary of operation to be solved) In the present invention, as a flow path body which is a constituent element of the fuel cell, a groove penetrating through the sheet-like member from the front surface to the back surface is made to progress in a zigzag shape in the plane direction. That in which the flow path was formed was used.
Therefore, in the case where a flow path capable of flowing the same flow rate is formed as compared with a conventional flow path body in which a groove formed by cutting one surface is used as a flow path, the thickness can be reduced. Therefore, the fuel cell can be further reduced in thickness.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an exploded view of the fuel cell of the present invention. In FIG. 1, 1 is a separator, 1
-1 is a through hole, 2 is a flow path body, 2-1 is a frame section, 2-2 is a flow path wall section, 2-3 is a flow path, 3 is a gasket, 3A is an opening, 4 is an electrode (anode side). ), 5 is an electrolyte membrane, 6 is an electrode (cathode side), 7 is a gasket, 7A is an opening, 8 is a flow path body, 9 is a separator, 9-1 is a through hole, and 10 is an electrolyte membrane electrode assembly. .

In the present invention, the separator 1, the flow path body 2, the gasket 3, the electrolyte membrane electrode assembly 10, the gasket 7,
By stacking the flow path body 8 and the separator 9 in this order, one fuel cell is constituted. Fuel cells are
It is constituted by stacking an arbitrary number of such cells. Hereinafter, each component will be described. (1) Separators 1 and 9 As a material of the separators 1 and 9, a material usually used for a separator is used. Note that a graphite gasket material can also be used. And 2 opened to them
Each of the two through-holes has a gas (eg,
It is used as an inlet and outlet for hydrogen and air). For example,
One through hole 1-1 is used as a hydrogen inlet, and the other through hole 1-1 is used as a hydrogen outlet. The position of the through hole 1-1 is opened at a position corresponding to an end portion of the flow channel 2-3 described later when the separator 1 is stacked on the flow channel body 2.

(2) Channels 2 and 8 FIG. 2 is a view showing the channel 2, and the reference numerals correspond to those in FIG. 2A is a plan view, and FIG. 2B is FIG.
It is sectional drawing in the AA of (a). As a material of the flow path body 2, a thin plate material (that is, a sheet-like member) is used. For example, a gasket material made of graphite is used. And
One zigzag flow path 2-3 is provided in this, but this flow path 2-3 is not a grooved flow path with one surface cut off, but is cut out so as to penetrate from the front surface to the back surface. Channel. The flow path wall 2-2 is adjacent to the flow path 2
The frame portion 2-1 is a peripheral portion surrounding the flow channel wall portion 2-2 and the flow channel 2-3 in a frame shape. The flow path body 8 has the same configuration (however, in the example shown in FIG. 1, the position of the end of the flow path is upside down with respect to the flow path body 2).

According to the present invention, the reason why the thickness can be reduced as compared with the prior art is in the manner of forming the flow path 2-3 as described above. In the conventional method of forming a groove by cutting one surface of a plate material to form a groove, the thickness of the concave portion of the groove (portion through which gas flows) and the thickness forming the bottom of the groove are absolutely necessary.
Only a part of the thickness of the plate could be used as a flow path.
However, in the present invention, the entire thickness of the flow path body (sheet-shaped member) can be used as the flow path, so that when forming flow paths having the same cross-sectional area, the thickness of the flow path body can be reduced (at least). The thickness of the portion below the step 311 of the frame body 31 can be reduced by the thickness corresponding to the bottom of the groove.

(3) Gaskets 3, 7 As the material of the gaskets 3, 7, a material used for a gasket (for example, a rubber-based gasket material) is usually used. Openings 3A and 7A are opened at the center of the gaskets 3 and 7, respectively, and are openings for fitting electrodes described in the next section. Therefore, the opening 3
The sizes of A and 7A are slightly larger than the size of the electrodes. Note that the thickness of the gaskets 3 and 7 may be elastically or plastically deformed at the time of lamination depending on the material thereof.

(4) Electrolyte Membrane Electrode Assembly 10 FIG. 3 is a sectional view of the electrolyte membrane electrode assembly 10. Electrolyte membrane electrode assembly 10 is formed by symmetrically joining electrodes 4 and 6 to the front and back surfaces of electrolyte membrane 5. The electrode 4 is an anode-side electrode, and the electrode 6 is a cathode-side electrode. In FIG. 1, the electrode 6 is not shown because it is hidden by the electrolyte membrane 5.

(Flow of Gas) In a fuel cell in which the above-described components are stacked, the supplied gas (eg, hydrogen, air) flows as follows. First, hydrogen supplied from one through hole 1-1 of the separator 1 is supplied to the flow path 2 of the flow path body 2.
-3 flows from one end toward the other end. When flowing, it flows while contacting the surface of the electrode 4, so that hydrogen necessary for the electrode reaction can be supplied to the electrode 4. From the other end, it goes out through the other through hole 1-1 to the outside. In addition, a product generated near the surface of the electrode 4 due to the electrode reaction is placed on such a flow and discharged to the outside. The same applies to the flow of air supplied from one through hole 9-1 of the separator 9.

The structure of the fuel cell of the present invention is as described above, and it is not necessary to perform a step of impregnating with a resin. Therefore, no labor and cost are required for this.

[0021]

As described above, the fuel cell of the present invention has the following effects. The fuel cell can be made thin. Since the flow path of the flow path body is not a groove-shaped flow path made by cutting one surface of the flow path body member, but a groove flow path formed by cutting out from the front surface to the back surface, Even with a flow path body that allows the same flow rate, it can be made thinner than a conventional flow path body. Therefore, the fuel cell can be made thin. Manufacturing costs are low. Since there is no need to impregnate the resin, compared to the conventional example in which the step of impregnating the resin is also adopted to reduce the thickness, the production is less complicated and the cost is lower.

[Brief description of the drawings]

FIG. 1 is an exploded view of a fuel cell of the present invention.

FIG. 2 is a view showing a flow path body of the fuel cell of the present invention.

FIG. 3 is a cross-sectional view of an electrolyte membrane electrode assembly.

FIG. 4 is a diagram showing a laminated structure of a main part of a fuel cell;

FIG. 5 is an exploded view of a stack of a constituent half of a conventional fuel cell.

FIG. 6 is a view for explaining an example of a conventional flow path component.

FIG. 7 is a plan view of a conventional flow path component.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Separator, 1-1 ... Through-hole, 2 ... Channel body, 2-1
... frame part, 2-2 ... flow path wall part, 2-3 ... flow path, 3 ... gasket, 3A ... opening, 4 ... electrode (anode side), 5 ... electrolyte membrane, 6 ... electrode (cathode side), 7 ... Gasket, 7
A: opening, 8: flow path, 9: separator, 9-1: through hole, 10: electrolyte membrane electrode assembly, 20: separator,
21: flow path constituent part, 22: electrode part (anode side), 23
... electrolyte membrane, 24 ... electrode part (cathode side), 25 ... flow path constituent part, 26 ... separator, 30 ... flow path body, 31 ... frame body, 301 ... convex part (flow path wall), 302 Road),
311: stepped portion, 312: through hole, 313: opening, K:
Battery configuration half

Claims (2)

[Claims] A first gasket; a first gasket; a first gasket;
A fuel cell in which a unit cell in which an electrode, an electrolyte membrane, a second electrode, a second gasket, and a second channel body are stacked in this order is stacked with a separator interposed therebetween.
The second flow path body, using a sheet-like member as its member,
The sheet-shaped member has a flow path formed by advancing in a zigzag shape in a plane direction from a front surface of the sheet member to a rear surface, and the first and second flow path bodies of the separator are formed. A fuel cell, wherein a through-hole for allowing gas to flow is formed at a position corresponding to the start end and the end of the flow path when stacked. 2. The fuel cell according to claim 1, wherein a graphite gasket material is used as the sheet member.