JPH0160899B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a stacked fuel cell, and particularly relates to increasing the area by joining electrodes.

[Conventional technology]

Conventionally, gas separation plates for general stacked fuel cells have been shown in FIGS. 1 and 2.
Figure 2 is a plan view of Figure 1 seen from the back side.
a, b, c, and d indicate the same positions in FIG. 1 and FIG. 2. In the figure, 1 is a convex portion of the uneven channel portion, 2 is a concave portion of the uneven channel portion, and 3 is a seal portion. Note that the arrow indicates the direction in which the reaction gas flows.

The stacked fuel cell is stacked by alternately stacking unit cells each having a fuel electrode, an electrolyte matrix, and an oxidizing agent electrode, each of which has a sealing material provided at the periphery of the electrode, and the gas separation plate. 3 is an enlarged perspective view of a part of the gas separation plate shown in FIG. 2, and FIG. 4 is a perspective view showing a state in which unit cells are stacked on the gas separation plate shown in FIG. 3. Figures 3 and 4
In both figures, the number of concavities and convexities in the concavo-convex channel portion is shown reduced. In the figure, 4 is a cell and 5 is a sealing material. In the case of a phosphoric acid fuel cell, the sealing material 5 used is fluorine-based rubber or carbon paper filled with silicon carbide and impregnated with phosphoric acid. The laminate stacked in the above manner has sides a-b, sides b-c in FIGS. 1 and 2,
Manifolds for supplying and discharging reaction gas are attached to the c-d and d-a sides, and the stacked fuel cell is operated by supplying oxidizing gas and fuel gas. Phosphoric acid fuel cells that use phosphoric acid as the electrolyte operate at around 200°C, and molten carbonate fuel cells that use carbonate as the electrolyte operate at around 650°C. In order to control this operating temperature, gas separation plates that also function as cooling plates are inserted into the stacked body every few layers, and temperature control is performed by liquid cooling or air cooling.

Next, the function of the gas separation plate will be explained. One of the roles of the gas separation plate is to supply the reaction gas through the concave and convex flow path, and the convex part 1 and the concave part 2
is for this purpose. Another role of the gas separation plate is to serve as a path for the battery cells 4 to flow. Therefore, a material with good electron conductivity is selected for the gas separation plate, but the contact resistance between the convex portion 1 of the uneven channel portion that is in direct contact with the cell 4 and the cell 4 must be as small as possible. It won't happen. Furthermore, one role of the gas separation plate is to seal the gas around the cell 4. If this seal is insufficient, accidents may occur such as reaction gas leaking to the outside of the cell or fuel gas and oxidant gas mixing, which could lead to an explosion. Furthermore, leakage or mixing of reactant gases greatly reduces the output of the battery. Therefore, gas sealing around the unit cells 4 is an important issue from the standpoint of safety and battery output. In particular, the contact between the gas separation plate and the sealing material 5 at the periphery of the cell 4 must be sufficient.

In the conventional gas separation plate, b-c in Fig. 1
side, d-a side and b-a side, d in Fig. 2
- A sufficient contact surface between the seal portion 3 and the seal material 5 on side c can be secured. However, since the other sides are perpendicular to the concavo-convex channel portion and have the concave portions 2, the contact surface with the sealing material 5 is reduced by half. Therefore, sides b-c in Figure 1, sides d-a and side b in Figure 2
-The sealing performance is lower than that of sides a and d-c.

As described above, the problem with conventional stacked fuel cells lies in the gas sealing properties around the unit cells 4, and the reason for this is that the contact area with the sealing material 5 at right angles to the uneven flow passages is Irregularities on gas separation plate 2,
1, it was to be smaller.

As a prior art to solve this problem,
A stacked fuel cell shown in FIGS. 5 to 8 was created.

FIGS. 5 and 6 are plan views showing gas separation plates according to this prior art. Reference numeral 6 denotes a cover whose side is smooth on the sealing material 5 side, and is provided in an uneven channel portion facing the sealing material 5. FIG. 7 is an enlarged perspective view showing the concave-convex channel portion facing the sealing material 5, excluding the cover 6 shown in FIG. The portion 7 is cut out to be lower than the other convex portions 1. In addition, in FIG. 7, the number of projections and depressions in the uneven flow path portion is shown as being reduced. Further, FIG. 8 shows, with a portion cut away, a state in which a cover 6 is inserted into the gas separation plate of FIG. 7, and unit cells 4 having a sealing material 5 on the peripheral edge are stacked. Here, it is desirable that the cover 6 and the gas separation plate be bonded together using an electron-conductive adhesive.

According to this prior example, unlike the conventional stacked fuel cell, the contact surface between the gas separation plate and the sealing material 5 has no irregularities, so the contact area is large, and the sealing performance is improved.

Incidentally, examples close to the preceding examples shown in Figs.
-There is one published in No. 201768.

Incidentally, in order to increase the output of the stacked fuel cell, it is desired to use a unit cell 4 with a larger area. However, producing a large-area single cell 4 requires large-scale electrode manufacturing equipment and many techniques, resulting in high costs. Therefore, we created a large-area electrode body by joining several small-area fuel electrodes and oxidizer electrodes in a plane with a gas sealing material interposed.
It would be desirable to create bonded single cells based on this and increase the area.

[Problem that the invention seeks to solve]

However, the conventional structure of the gas separation plate has a problem in that sufficient gas sealing performance cannot be ensured by joining the cells at uneven locations.

This invention was made to solve the above-mentioned problems, and its purpose is to obtain a large-area stacked fuel cell by joining multiple unit cells while ensuring sufficient gas sealing properties. do.

[Means for solving problems]

The stacked fuel cell according to the present invention includes a fuel electrode body in which a plurality of electrodes are connected in a plane with a gas sealant interposed therebetween, an electrolyte matrix, and a plurality of electrodes connected in a plane with a gas sealant in between. a unit cell having an oxidizer electrode body connected to the oxidizer electrode body; A gas separation plate having an uneven oxidant gas flow path formed by grooves is provided, a plurality of the cells and the gas separation plate are alternately stacked, and the sealing material of the cell is applied to the gas separation plate. In the stacked fuel cell, which faces the uneven flow path portion, a cover is provided on the uneven flow path portion that faces the seal material interposed between the electrodes, and the sealing material side is smooth.

[Effect]

The cover in this invention improves the sealing performance between the sealing material interposed between the electrodes and the uneven flow path, so it has sufficient gas sealing performance for a large-area stacked fuel cell by joining multiple unit cells. is obtained.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 9 and 10 are plan views showing a gas separation plate according to an embodiment of the present invention, in which a cover 6 with a smooth sealing material 5 side similar to that shown in the above-mentioned prior example is shown.
By providing a position for inserting the gas separation plate in the center of the gas separation plate, two unit cells 4 can be joined in a two-dimensional manner. FIG. 9 shows a case where the sealing material 5 interposed between the cells 4 faces perpendicularly to the uneven flow path, and the cover 6 is inserted by cutting out the convex part 1 in the center of the uneven flow path. ing. FIG. 10 shows a case in which the sealing material 5 faces parallel to the uneven channel portion, and the width of the convex portion 8 of the uneven channel portion that comes into contact with the sealing material 5 is widened. This structure was adopted in order to obtain a sufficient seal width. As long as the surface is flat and there is a sufficient seal width, the unit cells 4 can be easily joined.

In addition, the convex part 7 of the uneven channel part where the cover 6 is provided is cut out to be lower than the other convex parts 1, and the cover 6 is inserted into this part and the unit cell having the sealing material 5 is cut out. The state in which 4 is stacked is the same as in the prior example shown in FIGS. 7 and 8.

FIGS. 11 and 12 are plan views showing gas separation plates according to other embodiments of the present invention, and FIGS.
This is an attempt to join two unit cells 4 by combining the embodiments shown in FIGS. 5 and 10 and the preceding examples shown in FIGS. 5 and 6. That is, the cover 6, which is smooth on the sealing material 5 side, is provided at the center and end portions of the uneven channel portion facing the sealing material 5. 12th
In the figure, the width of the convex portion 8 at the center of the concavo-convex channel portion facing the sealing material 5 is widened. With this, it is possible to join the two single cells 4,
Moreover, the sealing performance near the inlet and outlet of the reaction gas is also improved.

FIGS. 13 and 14 are plan views showing a gas separation plate according to another embodiment of the present invention, in which four unit cells are to be joined.

In the above embodiments, the cover 6 is mainly made of a smooth material on both the sealing material 5 side and the anti-sealing material side, but the uneven flow path portion of the gas separation plate facing the sealing material 5 It is also possible to cut out a notch and provide a cover in this portion, which is smooth on the side of the sealing material 5 and has an uneven surface on the side opposite to the sealing material so as to secure a flow path.
FIG. 15 is a sectional view showing a gas separation plate according to another embodiment of the present invention. The uneven gas flow path portion facing the sealing material 5 is cut out to make it smooth 9, and a cover 6 is provided in this portion, the side of the sealing material 5 is smooth and the side opposite to the sealing material is uneven so as to secure a flow path.
has been established.

In each of the gas separation plates according to the above embodiments, the cross-sectional area of the reaction gas flow path at the location where the cover 6 is inserted is smaller than that of the other flow paths by the thickness of the cover 6.

FIG. 16 is a sectional view showing a gas separation plate according to another embodiment of the present invention, in which the width of the protrusion formed on the cover 6 is made narrower than the width of the protrusion 1 formed on the gas separation plate, and the This attempts to keep the cross-sectional area of the road constant. Note that even when the cover 6 is a flat plate, the cross-sectional area of the flow path can be kept constant by narrowing the width of the convex portion 1 of the gas separation plate where the cover 6 is inserted. Further, the same effect can be expected by reducing the number of convex portions forming the flow path portion where the cover 6 is inserted.

In the above embodiment, the cover 6 and the sealing material 5 are formed separately, but the cover 6 may be bonded to the sealing material 5 and formed integrally with the sealing material 5.

In addition, in the above embodiment, two and four single cells 4
Although the case where the cells 4 are bonded is shown, the present invention is not limited to this, and any number of unit cells 4 may be bonded.

[Effects of the Invention] As described above, according to the present invention, there is provided a fuel electrode body and an electrolyte matrix in which a plurality of electrodes are connected in a plane with a gas sealant interposed therebetween, and a plurality of electrodes connected in a plane with a gas sealant. A unit cell having an oxidizer electrode body connected planarly with a material interposed therebetween, an uneven fuel gas flow path portion formed with a plurality of grooves on a surface facing the fuel electrode body, and the oxidizer electrode body. A gas separation plate having an uneven oxidant gas flow path formed by a plurality of grooves on opposing surfaces is provided, a plurality of the above-mentioned unit cells and a plurality of gas separation plates are alternately stacked, and a sealing material for the above-mentioned unit cells is provided. In the stacked fuel cell that faces the uneven flow path portion of the gas separation plate, a cover whose sealing material side is smooth is provided on the uneven flow path portion facing the sealing material interposed between the electrodes.
A stacked fuel cell with a large area can be obtained by joining a plurality of unit cells, and also has the effect of achieving sufficient sealing performance.

[Brief explanation of drawings]

Figures 1 and 2 are plan views showing conventional gas separation plates, Figure 3 is an enlarged perspective view of a part of the gas separation plate in Figure 2, and Figure 4 is the gas separation plate in Figure 3. FIG. 5 is a perspective view showing a state in which single cells are stacked on a board;
FIG. 6 is a plan view showing the gas separation plate according to the prior example, and FIG. 7 is an enlarged perspective view showing the concave-convex channel portion facing the sealing material, excluding the cover of the gas separation plate in FIG. , FIG. 8 is a partially cutaway perspective view showing a state in which a cover is inserted into the gas separation plate of FIG. 7 and unit cells are stacked, and FIGS. 9 and 10 are gas separation according to an embodiment of the present invention. Plan view showing the board, No. 11
14 are plan views showing gas separation plates according to other embodiments of the present invention, and FIGS. 15 and 16 are sectional views showing gas separation plates according to other embodiments of the invention. In the figure, 1 is a convex part of an uneven channel part, 2 is a concave part of an uneven channel part, 4 is a cell, 5 is a sealing material,
6 is a cover, and 7 and 9 are cutout portions of the uneven channel portion. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A fuel electrode body, an electrolyte matrix, in which a plurality of electrodes are connected in a planar manner with a gas sealant interposed therebetween, and a plurality of electrodes in a planar connection in which a plurality of electrodes are connected in a planar manner with a gas sealant in between. A unit cell having an oxidizer electrode body, an uneven fuel gas flow path portion formed with a plurality of grooves on the surface facing the fuel electrode body, and a plurality of grooves formed on the surface facing the oxidizer electrode body. a gas separation plate having an uneven oxidant gas flow path section, a plurality of the above cell cells and a plurality of gas separation plates are alternately stacked, and the sealing material of the above cell cell is applied to the uneven flow path section of the gas separation plate. 2. A stacked fuel cell, characterized in that a cover having a smooth surface on the side of the sealing material is provided on the uneven channel portion facing the sealing material interposed between the electrodes. 2 Cut out the uneven flow path facing the sealing material,
2. The stacked fuel cell according to claim 1, wherein this portion is provided with a cover having a smooth surface on the side of the sealing material. 3 Cut out the uneven channel portion facing the sealing material,
Claim 1, characterized in that this portion is provided with a cover that is smooth on the side of the sealing material and that is uneven on the side opposite to the sealing material so as to secure a flow path.
Stacked fuel cell described in Section 1.