JPH0341407Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an improvement of a partition plate of a fuel cell applied to, for example, an alkaline aqueous electrolyte fuel cell.

[Conventional technology]

First, FIG. 1 shows the configuration of the conventional alkaline aqueous electrolyte fuel cell mentioned above. In the figure 1
5 is a single cell composed of a fuel electrode 2, an air electrode 3, and a cell frame 4 that holds both electrodes, and 5 is a corrugated partition plate made of nickel plate, which connects multiple single cells 1 to each other. are laminated through the partition wall plate 5,
It makes up the cell stack. Here, bulkhead plate 5
defines a fuel chamber 6 for supplying fuel to the fuel electrode 2 on the one hand and an air chamber 7 for supplying air to the air electrode 3 on the other hand between adjacent single cells 1, and contact across the
The single cells 1 are electrically connected in series. Note that 8 is an electrolyte chamber defined inside each single cell 1.

However, the conventional configuration described above has the following drawbacks. That is, in order to maintain airtightness of the gas chamber defined between the partition plate 5 and the single cell 1, a flat rubber sheet is placed as a sealing member between the periphery of the partition plate 5, which is a nickel plate, and the cell frame 4. However, such a configuration not only increases the number of component parts and assembly man-hours, but also usually uses a thin flat rubber sheet with a thickness of 1 mm or less in order to reduce the size of the cell stack, so its thickness and dimensional accuracy may be affected. Due to variations in the sealing performance, sufficient sealing performance cannot be obtained. In addition, the nickel plate used for the partition plate 5 has poor elasticity, and if the pressure applied to the electrode is increased to lower the current collecting resistance, the electrode with low mechanical strength may be damaged, and conversely, the electrode may be damaged. If the pressure bonding force of the partition plate is weakened, the contact pressure will be reduced accordingly, or some portions will not be in contact with the electrode surface, resulting in an increase in current collection resistance, making it impossible to obtain good current collection performance.

In view of the above points, we have developed a partition plate for a fuel cell that eliminates the drawbacks of the conventional structure and achieves good gas chamber sealing performance and current collection performance between electrodes with a small number of components, as shown in Figure 2. As shown in Figure 2, a conductive rubber sheet is tightly sandwiched and inserted between the cell frames of adjacent single cells on at least a part of the partition plate, and both sides of the conductive rubber sheet are applied to the opposing electrodes. A method has been proposed in which adjacent wire meshes are overlapped.

This will be explained below based on FIG. Between the individual cells 1 constituting the cell stack, there is a partition plate 1 which is a composite of a conductive rubber sheet 9 and a wire mesh 10 placed on both sides of the rubber sheet 9.
1 are interposed therebetween, and the laminate in which unit cells 1 and partition plates 11 are stacked alternately is tightened in the stacking direction by stack tightening bolts (not shown). Among these, the conductive rubber sheet 9 has an overall flat plate shape as shown in FIGS. 4 and 5, and is manufactured, for example, as follows. In other words, a large number of flexible wire meshes with extremely fine wire diameters are stacked together and molded together with rubber raw materials.
Slice thinly in the direction perpendicular to the overlapping surface of the wire mesh and form into a sheet. This rubber sheet 9 has high electrical conductivity in the thickness direction, with the cut surfaces of the wire mesh wires 12 embedded throughout the sheet extending through the sheet being exposed on both sides of the plate surface. Furthermore, the metal wires embedded in the rubber sheet are thin and flexible and do not impair the elasticity of the rubber. conductive rubber sheet 9
are closely held between the cell frames 4 of adjacent single cells 1 when assembling the cell stack. On one side of both surfaces, a fuel gas chamber is defined between the fuel electrode 2 and on the other side, an air chamber is defined between the air electrode 3 and the cell frame 4 and the rubber sheet 9. The seal is created by close contact with the material. Further, the wire mesh 10 is smaller in area than the rubber sheet 9 and has a size corresponding to the electrode area of a single cell.

With this configuration, current flows between the single cells along the path of electrode → wire mesh → conductive rubber → wire mesh → electrode, and the single cells are electrically connected in series. Moreover, gas chambers for fuel and air are defined on both sides of the rubber sheet 9, the circumference of which is hermetically sealed between the rubber sheet 9 and the single cell. Therefore, first, due to the elastic force of the rubber sheet 9, the rubber sheet 9
Since the wire mesh 10 interposed between the electrode and the counter electrode uniformly adheres to the electrode surface, good current collection performance can be obtained.
In this case, even if there are some irregularities on the electrode, the elastic force of the rubber sheet will ensure that the wire mesh is well pressed and adhered, and furthermore, localized excessive pressure loads can be prevented by the rubber sheet 9.
There is no risk of damaging the electrodes. Further, since the conductive rubber sheet constituting the partition plate 11 itself serves as a gasket that is in close contact with the cell frame 4, the flat rubber gasket as a separate component in the conventional configuration shown in FIG. 1 is no longer necessary. In this way, excellent current collection performance and gas chamber airtightness can be achieved with a simple configuration.

[The problem that the idea aims to solve]

Even in the improved method as described above, there are the following problems. That is, since the partition plate is constructed as a composite of a flat conductive rubber sheet and wire meshes arranged on both sides of the rubber sheet so as to be in contact with the opposing electrode surfaces, the number of parts is large.

This idea was made in view of the above points,
The purpose is to provide a fuel cell having a partition plate with a small number of parts.

[Means to solve the problem]

The above object is achieved by configuring the fuel cell as follows. That is, a gas chamber for fuel and air is defined between the single cells,
In a fuel cell in which the single cells are laminated with intervening conductive partition plates for electrically connecting them in series to form a cell stack, the partition plates are closely attached at least in part between the cell frames of adjacent single cells. The partition plate is constructed using a conductive rubber sheet that is sandwiched and interposed, and the partition plate is constructed as a concave-convex plate having protrusions on both surfaces thereof respectively bulging toward the counter electrode surface.

〔Example〕

An embodiment of this invention is shown in FIGS. 3 and 6. In this embodiment, instead of the wire mesh 10 and the flat conductive rubber sheet shown in FIG. It is made as a rubber sheet. The protrusions 13 may be formed into a band shape as shown in the figure, or may be formed by uniformly distributed circular protrusions. When the cell stack is assembled, the projections 13 come into contact with the electrode surfaces of each single cell 1 to collect current, as shown in FIG.

In addition to the above-mentioned conductive rubber sheet, for example, a conductive rubber sheet in which the surface of glass particles coated with a conductive material may be mixed in the rubber to obtain high conductivity may also be used. can.

[Effect of idea]

According to this invention, the conductive rubber sheet has a current collection function, a sealing performance, and a gas chamber function, so that the number of parts can be reduced. Since a conductive rubber sheet having protrusions can be easily manufactured by molding, the effect of reducing the number of parts is significant.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the structure of a conventional fuel cell.
Fig. 2 is a sectional view of the structure of an improved conventional fuel cell, Fig. 3 is a sectional view of the structure of an embodiment of this invention, Fig. 4 is a plan view of the conductive rubber sheet in Fig. 2, and Figs. Figure 6 is Figure 2 and Figure 3, respectively.
FIG. 2 is an enlarged cross-sectional perspective view of a part of the conductive rubber sheet in the figure. 1: Single cell, 2, 3: Electrode, 4: Cell frame, 6,
7: gas chamber, 9: conductive rubber sheet, 10: wire mesh, 13: protrusion.

Claims (1)

[Scope of utility model registration request] In a fuel cell in which a cell stack is constructed by stacking unit cells with a conductive partition plate interposed between them to define gas chambers for fuel and air and to electrically connect the unit cells in series, the partition wall At least a part of the plate is constructed using a conductive rubber sheet that is tightly sandwiched and inserted between the cell frames of adjacent single cells, and the partition plate has a conductive rubber sheet on both sides that expands toward the opposing electrode surface. 1. A fuel cell characterized in that it is constructed as a concavo-convex plate having protrusions.