JPS6352751B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stacked fuel cell, and particularly to a divided electrode and a gas separation plate therefor.

Conventionally, this type of gas separation plate is shown in Figures 1 and 2.
I got what is shown in the figure. FIGS. 1 and 2 are plan views of the gas separation plates on the fuel side and oxidizer side, respectively. Note that the convex portions of the uneven portions on the plane are indicated by diagonal lines. The same applies to each figure below. In Fig. 1, 1 is a fuel flow path, 2 is a contact part with the electrode on the fuel side, and 3 is an electrolyte replenishment mechanism (hereinafter referred to as an external reservoir).The one provided on the gas separation plate is usually called an external reservoir. The one provided in the electrode is called an internal reservoir.) 4a,
4b, 4c, and 4d are supply holes used for electrolyte replenishment. Further, in FIG. 2, 5 is an oxidizing agent flow path, 6 is a contact portion with the electrode on the oxidizing agent side, 4a, 4b, 4
c and 4d are supply holes used for electrolyte replenishment. Note that the fuel flow path 1 and the oxidizer flow path 5 are provided in directions perpendicular to each other. Note that 7 is a location where an external reservoir can be provided, and the external reservoir 3 may not be provided on the fuel side but may be provided on the oxidizer side. A stacked fuel cell consists of a non-conductive porous member impregnated with an electrolyte between gas separation plates, and electrodes on the fuel side and oxidizer side that sandwich this material and have air permeability and water repellency. It has a structure in which a large number of these are stacked. In this case, either an end plate or a double-groove plate is used as the gas separation plate, but in the case of an end plate, either the structure shown in Figure 1 or 2 is provided on one side, and in the case of a double-groove plate, the structure shown in Figure 1 or 2 is provided on one side. The structures shown in FIGS. 1 and 2 are provided on the front and back sides. FIG. 3 is a plan view showing the mounting position of the manifold for supplying fuel and oxidizer with respect to the gas separation plate. In Fig. 3, 8 is the manifold on the fuel inlet side, 9 is the manifold on the fuel outlet side, 10 is the manifold on the oxidizer inlet side, 11 is the manifold on the oxidizer outlet side, and 12 is the flow path of the gas separation plate on the fuel side. be.

Next, the operation will be explained. The fuel and oxidant supplied to the fuel flow path 1 and the oxidizer flow path 5 are as follows:
The porous electrode is diffused and ionized at the interface with a non-conductive porous member impregnated with electrolyte, and both ions react to form a compound. If the fuel is hydrogen, water is produced and an electric current is generated between both electrodes. Due to the contact between the electrode and the gas separation plate, current flows through the gas separation plate to the external circuit. Furthermore, although the electrolyte expands and contracts due to dilution with water as a product and thermal cycles of the fuel cell, this effect is alleviated by the external reservoir 3. In addition, during long-term operation, the electrolyte evaporates and disappears, so the supply holes 4a and 4
Electrolyte is supplied to the porous member through the external reservoir 3 from b, 4c, and 4d. After the fuel cells are stacked, a manifold is attached and operated. Fuel enters the fuel flow path 1 from the manifold 8 on the fuel inlet side, and after being consumed within the cell, the remaining gas exits to the outside through the manifold 9 on the fuel outlet side. On the other hand, the oxidizer enters the oxidizer channel 5 from the manifold 10 on the oxidizer inlet side, and after being consumed within the cell, the remaining gas exits through the manifold 9 on the fuel outlet side. On the other hand, the oxidizing agent enters the oxidizing agent channel 5 from the manifold 10 on the oxidizing agent inlet side, and after being consumed within the battery, the remaining gas exits through the manifold 11 on the oxidizing agent outlet side.

Conventional fuel electrodes and oxidizer electrodes cover almost the entire surface of the gas separation plate, so large electrodes are susceptible to uneven stress and break easily.
This was an obstacle to increasing capacity.

This invention attempts to solve the above-mentioned problem, and the gas separation plate has band-shaped parts facing each other in the center of both sides and in which no flow path is formed, and the fuel flow path and the oxidizer flow path are approximately Ω. The shape of the electrode is symmetrical about the band-shaped portion as an axis, and the direction of the substantially Ω-shaped convex portion of the flow path is opposite on the fuel side and the oxidizer side, and the electrode is divided into two by the band-shaped portion. This reduces uneven stress on the electrodes and increases capacity.

An embodiment of the present invention will be described below with reference to the drawings. FIGS. 4 and 5 are plan views of the fuel side and oxidizer side, respectively, of the gas separation plate used in the present invention.
In FIG. 4, 1 is a groove-shaped fuel flow path, 2 is a contact portion with the fuel electrode, and as shown by diagonal lines,
This is a convex portion on the uneven surface of the gas separation plate. Reference numeral 13 denotes a strip-shaped portion provided in the center of the gas separation plate in which no flow path is formed, that is, a first electrode connecting portion, and both sides of the connecting portion are formed in the same shape symmetrically. The fuel flow paths 1 are formed in a substantially Ω-shape on both sides of the first electrode connection portion, and are formed facing each other such that the substantially Ω-shaped recesses are on the first electrode connection portion side. Reference numeral 7 denotes a portion where an external reservoir can be formed, and is formed at two sides parallel to the first electrode connection portion, a portion extending from these two sides, and a substantially Ω-shaped recess. Reference numerals 14, whose arrangement positions are indicated by broken lines, are two separate fuel electrodes that contact the gas separation plate. The electrodes are fixed by a pressing force applied in the stacking direction at the first electrode connection portion. A gasket surrounds the fuel electrode 14 and between both fuel electrodes. In FIG. 5, reference numeral 5 indicates a groove-shaped oxidant flow path, and 6 indicates a contact portion with the oxidizer electrode, which is a convex portion of the uneven surface of the gas separation plate. Reference numeral 15 denotes a second electrode connecting portion, which is provided opposite to the central portion of the gas separation plate in FIG. is formed. The oxidant channels 5 are each formed in a substantially Ω-shape on both sides of the second electrode connection portion, with the substantially Ω-shaped convex portions facing toward the second electrode connection portion. 16 is an external reservoir,
Two sides parallel to the second electrode connection part, a part extending from these two sides into the approximately Ω-shaped recess, and a part extending from the second electrode connection part to a side perpendicular to this. It is formed. The oxidizer electrode 17, whose arrangement position is indicated by a broken line, is in contact with the gas separation plate, and is in contact with almost the entire surface of the gas separation plate, and is arranged with an interval at the second electrode connection part. Both oxidizer electrodes are fixed by a pressing force applied in the stacking direction at the second electrode connection portion. The periphery of the oxidant electrode 17 is surrounded by a gasket. Note that the external reservoir 16 may not be provided on the oxidizer side but may be provided on the gas separation plate on the fuel side, and FIG. 6 shows a plan view in the case where the external reservoir 18 is provided on the fuel side. FIG. 7 is a plan view showing the position where the manifold is attached to the gas separation plate used in the present invention. 7th
In the figure, 19 is a manifold on the fuel inlet and oxidizer outlet sides, 20 is a manifold on the fuel outlet and oxidizer inlet sides, 21 is on the oxidizer outlet side, 22 is on the oxidizer inlet side, 23 is on the fuel inlet side, and 24 is the fuel outlet It's on the side. In addition, in the stacking, two sets of electrodes on the fuel side and the oxidizer side, each having an area of about half of the gas separation plates, are inserted between the gas separation plates and connected at the first and second electrode connecting parts 13 and 15. Do it by doing this.

Next, the operation will be explained. In FIGS. 4 and 5, the fuel flows near the first electrode connection part 13 near the inlet and outlet of the fuel flow path 1, and flows far away near the center, and the oxidant flows near the inlet and exit of the oxidizer flow path 5. Although the flow is far from the two-electrode connecting portion 15 and close to the center, the length of each flow path is approximately the same. In Figures 5 and 6, the external reservoir 1
6 and 18 are used to alleviate the effects of expansion and contraction of the electrolyte due to dilution with the product water and thermal cycles of the fuel cell, and in particular, approximately Ω.
External reservoir 16 provided in the concave portion of shaped flow channels 1 and 5,
18, even if the area of the gas separation plate is increased, the amount of electrolyte near the center of the divided fuel electrode 14 or oxidizer electrode 17 can be easily and quickly adjusted. The surface of the electrode that contacts the external reservoirs 16, 18 is made hydrophilic, and the electrolyte is made of a non-conductive porous member and the external reservoirs 16, 18.
Make it possible to go back and forth. In addition, since the electrolyte evaporates and disappears during long-term operation, the supply holes 4a and 4
b, 4c, and 4d replenish the porous member with electrolyte through external reservoirs 16 and 18. After the fuel cell is stacked, a manifold 19 on the fuel inlet and oxidizer outlet sides and a manifold 20 on the fuel outlet and oxidizer inlet sides are attached and operated (FIG. 7). The oxidant enters the oxidant flow path 5 from the oxidant inlet side 22 and the remaining gas after being consumed within the cell exits through the oxidant outlet side 21. On the other hand, fuel enters the fuel flow path 1 from the fuel inlet side 23,
After being consumed within the cell, the remaining gas exits through the fuel outlet side 24. As can be seen from Fig. 7, the arrangement of manifolds 19 and 20 is
Since there is only one side, the other two sides can be used for other purposes, such as cooling arrangement.

In the above embodiment, the electrode connection portion is not provided with an external reservoir, but the electrode connection portion may be provided with an external reservoir. Further, in the above embodiment, each flow path is shown to be independent, but a detour flow path 25 may be provided at the inflection point of the flow path as shown in FIG. The inflection point 26 may be streamlined.

As described above, in the present invention, the gas separation plate has band-shaped portions facing each other in the center portions of both sides and in which no flow path is formed, and the fuel flow path and the oxidizer flow path are approximately Ω-shaped and the band-shaped portion is It is line symmetrical about the axis, and the direction of the approximately Ω-shaped convex portion of the flow path is opposite on the fuel side and the oxidizer side, and the electrode is symmetrical with the band-shaped portion.
Because it is divided, even if the battery becomes larger, the size of one electrode will be smaller than the size after division, which can alleviate uneven stress on the electrode.
Since the occurrence of cracks in the electrodes can be reduced, it is advantageous for achieving a larger capacity of the battery.

[Brief explanation of the drawing]

Figure 1 is a plan view of a conventional gas separation plate on the fuel side.
Figure 2 is a plan view of a conventional gas separation plate on the oxidizer side.
Fig. 3 is a plan view showing the mounting position of the manifold relative to a conventional gas separation plate, Fig. 4 is a plan view of a gas separation plate on the fuel side used in an embodiment of the present invention, and Fig. 5 is a plan view of the gas separation plate according to the present invention. FIG. 6 is a plan view of a gas separation plate on the oxidizer side used in one embodiment, FIG. 6 is a plan view of a gas separation plate on the fuel side used in another embodiment of the invention, and FIG. 7 is an embodiment of the invention. FIG. 8 is a plan view of a gas separation plate on the oxidizer side used in another embodiment of the present invention, and FIG. 9 is a plan view showing the mounting position of the manifold with respect to the gas separation plate used in FIG. 3 is a plan view of a gas separation plate on the fuel side used in the embodiment. 1... Fuel flow path, 4a to 4d... Electrolyte supply hole,
5... Oxidizing agent channel, 13... First electrode connection part, 14
... fuel electrode, 15 ... second electrode connection part, 16 ... external reservoir, 17 ... oxidizer electrode. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] 1. A unit cell having a flat fuel electrode and an oxidizer electrode facing each other with an electrolyte matrix holding an electrolyte interposed therebetween, and having a groove-shaped fuel flow path on one surface and a groove-shaped fuel flow path on the other surface. A plurality of gas separation plates each having a groove-shaped oxidizer flow path are alternately stacked with the fuel flow path and the oxidizer flow path facing the fuel electrode and the oxidizer electrode, respectively. In a stacked fuel cell that generates electricity by supplying a fuel and an oxidant to the agent flow paths, the gas separation plate has band-shaped portions facing each other in the center of both sides, in which no flow path is formed, and the gas separation plate The channel and the oxidant flow path are approximately Ω-shaped and are symmetrical about the belt-shaped portion as an axis, and the direction of the approximately Ω-shaped convex portion of the flow path is opposite on the fuel side and the oxidizer side, and A stacked fuel cell characterized in that the electrode is divided into two by the strip-shaped portion. 2. The stacked fuel cell according to claim 1, wherein an external reservoir is formed in a substantially Ω-shaped recess of the gas separation plate. 3. The stacked fuel cell according to claim 1 or 2, wherein external reservoirs are formed on two sides parallel to the band-shaped portion of the gas separation plate.