JPH07161366A - Separator for fuel cell - Google Patents

Abstract

PURPOSE:To control the pressure difference between electrodes and improve the flow rate distributing function by keeping balance between pressure loses of a fuel gas supplied to the anode side and an oxidizing gas supplied to the cathode side. CONSTITUTION:Gas flow routes in the cathode side and gas flow routes in the anode side are formed in the front and the rear sides of the center part of the center plate 9 except the peripheral parts by press-processing. Manifold 7 to send an oxidizing gas to the gas flow routes to the cathode side and manifold 7 to send a fuel gas to the gas flow routes in the anode side are formed in the peripheral parts of the center plate 9. Small projected parts 19 are formed in the gas flow route faces 12a which are communicated with the gas flow routes in the cathode side in the peripheral parts of the center plate 9 and projected parts 20 with wide width are formed in the gas flow route faces which are communicated with the gas flow routes in the anode side. The flow of the fuel gas is regulated by the projected parts 20 with wide width.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell separator used for partitioning cells in a fuel cell used in the energy sector for directly converting chemical energy of fuel into electric energy.

[0002]

2. Description of the Related Art Among fuel cells, a molten carbonate fuel cell has a tile (electrolyte plate) 1 in which a molten carbonate as an electrolyte is impregnated in a porous material as a cathode (oxygen electrode), as shown in FIG. ) 2 and an anode (fuel electrode) 3 sandwiched between them, and a potential difference generated between the cathode 2 and the anode 3 by supplying the oxidizing gas OG to the cathode 2 side and the fuel gas FG to the anode 3 side. One cell 4 is configured to generate power by means of the above, and each cell 4 is laminated in multiple layers via a separator 5 to form a stack.

The separator 5, which serves as a partition when the cells 4 of the fuel cell are stacked, has an unevenness serving as a gas flow path on the front and back sides in the central portion excluding the peripheral portion in the internal manifold type fuel cell. Oxidizing gas OG in the surrounding area
A manifold 6 for supplying / discharging the fuel gas FG and a manifold 7 for supplying / discharging the fuel gas FG are provided as a wet seal portion, and are used for supplying / discharging each gas so that different gases flow on both front and back surfaces of the separator 5. The configuration is such that the manifold and the gas passage in the central portion are communicated with each other. Reference numeral 8 is a distance piece cut out in the central portion and arranged in the peripheral portion of the separator 5.

Further, as the separator 5, the uneven portion for forming the gas flow path in the central portion is etched, machined,
There is a type that is molded by a press or the like, or a press type that has corrugated plates arranged on both sides of the center plate to form a gas flow path by the corrugated plates.

In the case of the press type separator 5 which is an internal manifold type, as shown in FIGS. 4 and 5, one example is shown in FIGS. A gas flow path forming concavo-convex portion 10 in which a flow path 12 and an anode gas flow path 13 are formed is provided by press molding, and a central portion is cut out on the front and back sides of the peripheral portion of the center plate 9. Moreover, the mask plate 14 having a size larger than the surrounding tiles 1,
15 are arranged respectively, the peripheral portions of the mask plates 14 and 15 are bent and overlapped with the center plate 9, and the overlapped portion is fixed and sealed, and the cathode side is passed through the manifold 6 for supplying and discharging the oxidizing gas. The oxidizing gas is supplied to the gas flow path 12, and the fuel gas is supplied to the anode side gas flow path 13 through the fuel gas supply / discharge manifold 7, and the manifolds 6 and 7 of the center plate 9 are Small protrusions 1 formed by embossing the same shape on both the front and back sides of the peripheral part provided
7 and 18 are arranged at required intervals so that the small projections 17 and 18 keep the distance between the mask plates 14 and 15 and the center plate 9 constant, and to the gas flow paths 12 and 13. The flowing gas can be dispersed. Reference numeral 11 indicates a spacer block.

[0006]

However, in the molten carbonate fuel cell, since the gas flow rates on the cathode 2 side and the anode 3 side are largely different (10: 1 to 5: 1), the press type separator 5 described above is used. Like the center plate 9
It is difficult to balance the pressure loss on the cathode 2 side and the anode 3 side with the small protrusions 17 and 18 of the same shape provided by embossing around the manifolds 6 and 7,
It becomes difficult to control the inter-electrode differential pressure between the cathode 2 and the anode 3 and the internal and external differential pressure of the battery, and further, the pressure loss on the anode 3 side becomes small, so that there is a problem that the flow distribution performance deteriorates.

On the other hand, instead of the embossed small protrusions 17 and 18, there is also a type in which a shape such as a corrugated plate is formed by pressing, but in that case, in the gas width direction (direction perpendicular to the gas flow direction). However, there is still a problem with the flow distribution performance because the diffusion to the air flow is hindered.

Therefore, the present invention provides a fuel cell separator which can balance the pressure loss on the cathode side and the anode side, and can control the differential pressure between electrodes and improve the flow distribution performance. Is what you are trying to do.

[0009]

In order to solve the above-mentioned problems, the present invention forms a cathode-side gas flow path and an anode-side gas flow path on the front and back sides of the central portion of the center plate excluding the peripheral portion, A manifold for supplying and discharging an oxidizing gas, which is provided in the peripheral portion of the center plate, is connected to the cathode-side gas passage so that the oxidizing gas flows, and a manifold for supplying and discharging a fuel gas, which is provided in the peripheral portion of the center plate. In the fuel cell separator in which the anode side gas flow path and the fuel gas are communicated so that the fuel gas flows,
Small projections are arranged on the gas flow path surface that connects between the oxidizing gas supply / exhaust manifold of the center plate and the cathode side gas flow path, and the fuel gas supply / exhaust manifold of the center plate and the anode side gas flow are arranged. A wide projection having a large area for interrupting the flow of the fuel gas is arranged on the gas flow path surface that communicates with the path.

[0010]

[Function] Since the protrusion provided on the gas flow passage surface between the oxidizing gas supply / discharge manifold and the cathode gas flow passage is small,
The area that blocks the flow of the oxidizing gas fed to the cathode gas flow path is small, and the pressure loss is small. On the other hand, since the protrusion provided on the gas flow passage surface between the fuel gas supply / discharge manifold and the anode gas flow passage has a wide width, the area for interrupting the flow of the fuel gas fed to the anode gas flow passage is small. In addition to increasing the pressure loss, the fuel gas is easily diffused in the width direction. This balances the pressure loss between the cathode side and the anode side.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

1 (a), 2 (b), (b), (c), and (d).
4 shows an embodiment of the present invention. Similar to that shown in FIGS. 4 and 5, the cathode side gas flow passage 12 and the anode side gas flow passage 13 are formed on the front and back sides of the central portion of the center plate 9 excluding the peripheral portion. The gas flow path forming concavo-convex portion 10 is formed by press molding, and the oxidizing gas is caused to flow to the cathode side gas flow path 12 by the manifolds 6 and 7 provided in the peripheral portion of the center plate 9. In the fuel cell separator 5 in which the fuel gas is made to flow to the anode side gas flow path 13, between the manifold 6 for supplying and discharging the oxidizing gas of the center plate 9 and the cathode side gas flow path 12. Gas flow path surface 12 for communicating with
Small protrusions 19 such as circles formed by press working are arranged at a predetermined distance on a, and a gas flow for connecting between the manifold 7 for fuel gas supply / discharge of the center plate 9 and the anode side gas passage 13 is provided. Wide projections 20 such as ellipses formed by press working are arranged on the road surface 13a at required intervals to diffuse the flow of the oxidizing gas fed from the manifold 7 to the anode side gas passage 13 in the width direction. To do so.

When the separator 5 having the above structure is used between the cells 4 of the fuel cell as shown in FIG.
The gas flow path surface 12a in the peripheral portion of the center plate 9 (see FIG.
In (b), (c), and (d), since the small circular protrusions 19 are arranged on the upper side of the neutral line L, the oxidation that is fed from the manifold 6 toward the cathode-side gas flow channel 12 is performed. The gas flow is hardly regulated, and the pressure loss can be kept low. That is, the gas flow path surface 12 communicating with the cathode side gas flow path 12
Since the protrusion 19 of a is small, the area that blocks the flow of the oxidizing gas is small and the pressure loss is small.

On the other hand, in the gas passage surface 13a in the peripheral portion of the center plate 9 (the portion below the neutral line L in (b), (c) and (d) of FIG. 2) with respect to the anode side gas passage 13. Since the oblong wide projections 20 extending in the right angle direction are arranged, the flow of the fuel gas fed from the manifold 7 toward the anode gas flow path 13 is restricted by the projections 20 and distributed in the width direction. Therefore, the flow rate distribution performance can be improved while securing the pressure loss. That is, since the projection 20 on the gas flow path surface 13a that communicates with the anode-side gas flow path 13 is wide, the area (projected area) that blocks the flow of the fuel gas is large (pressure loss is large) and the gas in the width direction is wide. Easy to spread.

Therefore, the pressure loss on the cathode 2 side and the anode 3 side can be balanced, and the control of the inter-electrode differential pressure and the improvement of the flow rate distribution performance can be achieved at the same time.

In the above embodiment, the center plate 9
Although the shape of the small protrusion 19 provided in the peripheral portion of the is shown as a circle, it may be a square or the like, and the shape of the wide protrusion 20 is shown as an ellipse. It may be a shape, a rectangle, or the like, and further, in the embodiment,
The case where the center plate 9 itself is processed to be uneven to form the gas flow path forming uneven portions is shown, but the same applies to a separator in which corrugated plates are arranged as the gas flow path forming uneven portions on the front and back of the center plate 9. It goes without saying that various modifications can be made without departing from the scope of the present invention.

[0017]

As described above, according to the fuel cell separator of the present invention, a small protrusion is formed on the gas flow passage surface communicating with the cathode side gas flow passage in the peripheral portion of the center plate.
In addition, since wide projections are arranged on the gas flow path surface that communicates with the anode gas flow path, pressure loss can be kept low on the cathode side and flow rate can be distributed while ensuring pressure loss on the anode side. It is possible to improve the performance, and by doing this, it is possible to control the differential pressure between electrodes and improve the flow distribution performance by press working without increasing the number of parts, and to improve the battery performance and soundness at a relatively low cost. It exhibits excellent effects such as improving the properties.

[Brief description of drawings]

FIG. 1 is a partially cutaway plan view showing an embodiment of a fuel cell separator of the present invention.

FIG. 2 is an enlarged view of a portion A of FIG. 1, in which (a) is a plan view of the center plate, (b) is a view taken along the line BB of (a), and (c) is (a). C-C arrow view, (d) is a DD arrow view of (a).

FIG. 3 is a schematic view showing an example of a molten carbonate fuel cell.

FIG. 4 is a partially cut plan view showing an example of a press type separator.

5 is an enlarged arrow view in the E direction of FIG.

[Explanation of symbols]

 2 cathode 3 anode 5 separator 6 manifold for supplying / discharging oxidizing gas 7 manifold for supplying / discharging fuel gas 9 center plate 12 cathode gas flow path 12a gas flow surface 13 anode gas flow path 13a gas flow surface 19 projection 20 projection

Claims (1)

[Claims] 1. A manifold for supplying and discharging an oxidizing gas, wherein a cathode side gas flow path and an anode side gas flow path are formed on the front and back of a central portion excluding the peripheral portion of the center plate, and which is provided in the peripheral portion of the center plate. The cathode-side gas flow channel is connected so that the oxidizing gas flows, and the manifold for fuel gas supply and discharge provided in the peripheral portion of the center plate and the anode-side gas flow channel are connected so that the fuel gas flows. In the fuel cell separator that has been made,
Small projections are arranged on the gas flow path surface that connects between the oxidizing gas supply / exhaust manifold of the center plate and the cathode side gas flow path, and the fuel gas supply / exhaust manifold of the center plate and the anode side gas flow are arranged. A fuel cell separator, characterized in that wide projections having a large area for interrupting the flow of fuel gas are arranged on a gas flow path surface that communicates with a passage.