JPH0615402Y2 - Fuel cell - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a fuel cell having an improved separator used for partitioning a cathode side and an anode side of a fuel cell that directly converts chemical energy into electric energy. .

[Prior Art] Generally, a structure of a fuel cell as shown in FIG. 9 is known. As shown, tile (electrolyte plate) a is used as cathode b
It is sandwiched by both electrodes of the anode and the anode c from both sides, and the air d containing CO ₂ as a working fluid is supplied to the cathode b side,
A unit in which a fuel gas e such as H ₂ is supplied to the anode c side as a working fluid to generate power by a potential difference generated between the cathode b and the anode c is laminated in multiple layers via a separator f. Let me configure it.

As the separator f used in the fuel cell, as shown in FIG. 10 and FIG. 11, as one example, a supply passage h for air d and a supply passage i for fuel gas e are provided on one side of the peripheral portion. And an air discharge flow path j and a fuel gas discharge flow path k are formed on the other side of the peripheral portion, and an unevenness g serving as a gas flow passage is formed inside the area except the peripheral portion by etching or cutting. It is usually formed, and the anode side manifold plate 1 and the cathode side manifold plate m are used by being superposed on both sides of the peripheral edge portion of the separator f in order to allow the air d and the fuel gas e to flow along both sides of the separator f. It is done.

Further, the present applicant previously applied for “molten carbonate fuel cell” in Japanese Patent Application No. 60-121774.

This will be described with reference to FIGS. 12 and 13. By incorporating a manifold plate n having an internal hollow portion between a tile a and a flat plate-shaped separator f, a manifold plate n is provided between a cathode b and a separator f and an anode c. Spaces are formed between the separators f, flow path plates o and p, which form a flow path of the working fluid and have a predetermined spring characteristic, are interposed in each space, and the cathode b and the anode c are respectively formed. The flow path plates o and p are configured to be pressed against the tile a.

[Problems to be Solved by the Invention] However, the conventional examples described in FIGS. 9 to 11 have the following problems.

(1) Since the gas passage of the separator f is formed by etching or cutting, the manufacturing cost is high.

(2) When the gas flow path is manufactured by etching or cutting, there is a limit in itself, and the separator f becomes thick. For this reason, the flow passage cross-sectional area cannot be increased, and the pressure loss increases.

(3) The weight of the entire fuel cell is increased by the thick separator f and the manifold plates 1 and m provided on both sides of the separator f.

(4) Since the separator f and the manifold plates 1 and m are rigid bodies, if the thickness of the separator f varies, not only will a gap be created in the joint surface to cause gas leakage, but also the cathode b and the anode c will be pressed uniformly against the tile a. The tile a may be distorted and hair cracks may occur. In the "molten carbonate fuel cell" proposed by the applicant,
Although the above-mentioned problems have been almost solved, this proposal still has problems in terms of gas leakage and weight reduction of the entire fuel cell.

The present invention has been made in consideration of such circumstances, and an object thereof is to provide a fuel cell which can be manufactured at low cost, is lightweight, and can prevent gas leakage.

[Means for Solving the Problems] In order to achieve the above object, the present invention forms a battery unit by sandwiching an electrolyte tile having a smaller area than the tile between an anode and a cathode, and surrounding the battery unit. A fuel cell in which a plurality of layers are sequentially stacked with a spacer between them, and between the units facing each other vertically, a partition for partitioning the units and a separator for forming a fuel gas flow channel and an oxidizing gas flow channel on the front and back sides are provided. In the above, the electrolyte tiles of the battery unit are formed to have large and small battery units by varying the area in the vertical direction in the stacking direction, and the electrolyte tile having a large area is formed so as to protrude from the outer periphery of the spacer, and the electrolyte tile having a small area is formed. Is formed approximately the same as the outer circumference of the spacer, the separator is formed of a single thin plate, and the separator is To form a corrugated flow path that contacts the anode and cathode of the large and small battery units facing each other, and to form an oxidizing gas flow path on the cathode side of the flow path and a fuel gas flow path on the anode side. The inner peripheral side of the separator is formed with a flat surface portion sandwiched between the small area electrolyte tile and the spacer, and the outer peripheral side is formed with a sealing step portion that is in contact with the periphery of the large area electrolytic tile. In the portions located on both sides of the flow path part, forming an oxidizing gas inflow / outflow chamber connected to the oxidizing gas flow path and forming a fuel gas inflow / outflow chamber connected to the fuel gas flow path, and further, a separator positioned in the inflow / outflow chamber And the large and small battery units are aligned in the stacking direction, respectively, and an oxidizing gas supply / discharge port connected to the oxidizing gas inflow / outflow chamber and a fuel gas supply / exhaust connected to the fuel gas inflow / outflow chamber Air supply and exhaust part consisting of that obtained by the formation.

[Operation] As described above, the separator is formed by pressing from a single thin plate, and the flow path portion that is folded back in a wave shape and forms the oxidizing gas flow path and the fuel gas flow path on the front and back is formed in the center of the separator. A sealing step for forming an inflow / outflow chamber for the oxidizing gas and the fuel gas at the inlet / outlet side of each flow path of the oxidizing gas and the fuel gas, respectively, and for contacting and sealing the electrolyte tiles having different vertical areas around the separator. And a separator, by further forming the supply and exhaust ports of the oxidizing gas and the fuel gas, which are located in the respective inflow and outflow chambers and are aligned in the stacking direction, in the separator,
Since the fuel cell is constructed only by stacking the cell unit, the separator and the spacer, the fuel cell is extremely lightweight and can be manufactured without the need for joining or machining. Therefore, a significant reduction in manufacturing cost is achieved.

In addition, since the separator does not use a joining process, distortion due to heat such as brazing does not occur, and an elaborate one without bending is realized.

Further, the separator is formed from a thin plate rather than a rigid body, and since the sealing step around the separator is in contact with the upper and lower sides of the electrolyte tiles having different areas at the same time, it is difficult to form a gap in the flow path of the oxidizing gas or the fuel gas. Gas leaks are prevented.

[Embodiment] An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a side sectional view showing an embodiment of the fuel cell of the present invention.

The battery unit 11 is formed by providing the cathode 2 and the anode 3 on the upper surface and the lower surface of the tile 1, respectively. The cell unit 11 is composed of two types having different areas, and the cell units 11a and 11b having different large and small areas are alternately stacked in multiple stages via the spacer 7 and the separator 5 to form a fuel cell. This battery unit 11a, 11
Punch metals 4a and 4b are bonded to the cathodes 2a and 2b of b and the anodes 3a and 3b, respectively, for electrode protection.

In this stacking, the separator 5 shown in FIG. 3 is turned upside down and stacked with the spacer 7 placed around the punch metal 4a of the battery unit 11a having a large area.
After stacking the battery unit 11b having a small area sandwiched by the punched metal 4b thereon, the separator 5 is stacked thereon, the spacer 7 is placed on the separator 5, and the battery unit 11a having a large area is stacked thereon. Then, the fuel cell is configured by alternately stacking the cell units 11a and 11b and the spacers 7 and the separators 5 by turning them over.

Here, the separator 5 will be described in more detail.

FIG. 2 is a plan view of the separator 5, and FIGS. 3, 4, and 5 are III-III line, IV-IV line, and V- line of FIG. 2, respectively.
It is a sectional view taken along line V.

The separator 5 is formed by pressing a thin plate of stainless steel or Ni / SUS clad steel and has a rectangular planar shape.

The separator 5 is provided with a corrugated flow passage portion 5f at the center thereof, which forms an oxidizing gas passage and a fuel gas passage on the front and back sides.
Sealing step portions 5a, 5 for contacting and sealing the periphery of the upper and lower electrolyte tiles 1a, 1b having different areas.
b is formed. In addition, an inflow / outflow chamber 5r for the oxidizing gas and the fuel gas is formed on the front and back sides of the separator 5 located on the inlet / outlet side of the flow path portion 5f. Further, a supply / exhaust portion 5e is formed in the inflow / outflow chamber 5r for supplying / discharging the oxidizing gas and the fuel gas independently.

As shown in FIG. 2, the air supply / exhaust portion 5e is provided with a fuel gas H ₂ supply port 8 along rectangular inflow / outflow chambers 5r facing each other.
(Or an exhaust port) and an oxidizing gas O ₂ supply port 9 (or an exhaust port), and a plurality of these are provided alternately and are provided so as to be joined in the stacking direction.

As shown in FIG. 3, the flow passage portion 5f at the center of the separator 5 is folded back in a wave shape, and a fuel gas flow passage is formed on the upper side (anode 3 side) of this flow passage portion 5f and the lower side ( An oxidizing gas channel is formed on the cathode 2 side). When the separator 5 is turned upside down, the upper side when turned upside down makes contact with the anode 3 to form a fuel gas flow path, and the lower side when turned upside down contacts the cathode 2 to form an oxidizing gas flow path. To do.

Further, the inflow / outflow chamber 5r on the inlet / outlet side of the flow path portion 5f has a fuel gas inflow / outflow chamber formed on the upper side thereof and an oxidizing gas inflow / outflow chamber formed on the lower side thereof. The fuel gas passing through the fuel gas supply / discharge port 8 is connected to the fuel gas inflow / outflow chamber 5r above the separator 5, and the oxidant gas supply / discharge port 9 is connected to the oxidant gas inflow / outflow chamber below the separator 5. It is connected to 5r.

This will be described with reference to FIGS.

As shown in FIG. 4, the peripheral portion of the fuel gas supply / discharge port 8 formed in the separator 5 is lowered so as to come into contact with the electrolyte tile 1b having a small area, and thus the electrolyte having a large area above the electrolyte tile 1b. Since the space is formed with the tile 1a, the fuel gas inflow / outflow chamber 5r is formed. Similarly, when it is turned upside down, it comes into contact with the electrolyte tile 1b having a small area, and the fuel gas inflow / outflow chamber 5r is formed above it.

FIG. 6 shows the separator 5 and the battery units 11a and 11b.
A fuel gas flow path formed in the upper part of the flow path portion 5f from the fuel gas supply / exhaust portion 5e formed by the supply / discharge port 8 joined in the stacking direction to the fuel gas passage (or the outflow chamber). It shows the flowing state.

Further, as shown in FIG. 5, the peripheral portion of the supply / discharge port 9 for the oxidizing gas formed in the separator 5 is provided so as to be in contact with the electrolyte tile 1a, and between the electrolyte tiles 1b having a small area below the electrolyte tile 1a, An inflow / outflow chamber 5r for the oxidizing gas is formed.
Also, when the separator 5 is turned upside down, the oxidizing gas inflow / outflow chamber 5 is likewise formed between the electrolyte tiles 1b having a small area on the lower side.
to form r.

FIG. 7 shows the separator 5 and the battery units 11a and 11b.
The oxidant gas is formed from the oxidant gas supply / discharge port 5e formed in the stacking direction to the oxidant gas flow path formed in the lower part of the flow path portion 5f through the inflow chamber (or the outflow chamber). It shows the flowing state.

Such a separator 5 is turned upside down for each cell unit and used to form a fuel cell 6 shown in FIG. As described above, the punch metal 4 of the battery unit 11a having a large area is used.
Spacer 7 is laminated around a and battery unit 1
The separator 5 shown in FIG. 4 is turned upside down and overlaid on the la and the spacer 7. The step 5a on the outer circumference of the separator 5 is joined to the electrolyte tile 1a below, and the flat surface of the step 5b on the inner circumference is located on the spacer 7, and the punch metal is formed on the flat surface of the step 5b. The battery unit 11b having a small area sandwiched by 4b is stacked so that the lower periphery of the electrolyte tile 1b is joined. Further, the battery unit 11b is overlaid with the separator 5 in the state shown in FIG. 4, the flat portion of the stepped portion 5b of the spacer 5 is joined to the upper periphery of the electrolyte tile 1b of the unit 11b, and the spacer 7 is placed on the upper portion thereof. And the battery unit 11a having a large area is stacked via the punched metal 4a, and the electrolyte tile 1a around the battery unit 11a is joined to the peripheral step 5a of the separator 5 (FIG. 4). The fuel cell 6 is repeatedly formed.

The power generation operation of this fuel cell will be described below.

6 and 7 are a side sectional view in the vicinity of the fuel gas supply port 8 and a side sectional view in the vicinity of the oxidizing gas supply port 9 of the fuel cell, respectively. The open ends of the supply ports 8 and 9 are fitted and held by a washer 10 as shown in FIG.

First, the fuel gas H ₂ and the oxidizing gas O ₂ are supplied into the cell through the supply ports 8 and 9, respectively, and the operation of the fuel cell is started. The fuel gas H ₂ flows through the gap of the washer 10 in the fuel gas flow path on the upper side of each separator 5, that is, on the anode 3 side, and the oxidizing gas O ₂ is similarly on the lower side of each separator 5, that is, on the cathode 2 side. Flow through the oxidizing gas flow path.

Then, the fuel gas H ₂ and the oxidizing gas O ₂ react in each cell unit to generate an electromotive force.

In this cell reaction, the fuel gas and the oxidizing gas try to leak from the air supply / exhaust portion 5e and the flow passage portion 5f, but the sealing step portions 5a and 5b inside and outside the separator 5 are different from each other in the electrolyte tile having different upper and lower areas. Since it is in contact with 1a and 1b, a reliable seal can be achieved.

[Effect of the Invention] As described above, according to the present invention, the following excellent effects are exhibited.

(1) Since the separator is formed from a single thin plate, weight reduction is achieved, and as a result, the weight of the entire fuel cell can be reduced.

(2) Since the separator can be manufactured only by pressing without the need for joining or machining, the manufacturing cost is reduced and the manufacturing process is simplified.

(3) Since the separator is composed of a thin plate rather than a rigid body, a gap is unlikely to be formed in the attachment portion of the separator, and thus gas leakage is prevented.

(4) A sealing step is formed around the separator, and the step can be brought into contact with the upper and lower electrolyte tiles at the same time to ensure reliable sealing.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of the fuel cell of the present invention,
FIG. 2 is a plan view showing a separator according to the present invention, and FIG.
Fig. 4, Fig. 5 and Fig. 5 are respectively III-III line of Fig. 2,
IV-IV line and V-V line sectional views, FIGS. 6 and 7 are side sectional views showing the flow of fuel gas and oxidizing gas in the fuel cell, and FIG. 8 is used for the fuel cell. FIG. 9 is a side sectional view showing a conventional example, FIG. 10 and FIG. 11 are perspective views showing a conventional separator, and FIG. 12 is a side sectional view showing a second conventional example. Figure 13 is XIII in Figure 12
FIG. 6 is a sectional view taken along the line XIII of FIG. In the figure, 1 is an electrolyte tile, 2 is a cathode, 3 is an anode, 5 is a separator, 5e is an air supply / exhaust section, 5f is a flow path section,
Reference numeral 5f is an air supply / exhaust chamber, 7 is a spacer, 11a is a fuel cell unit having a large area, and 11b is a fuel cell unit having a small area.

Claims (1)

[Scope of utility model registration request] 1. An electrolyte tile is sandwiched between an anode and a cathode having an area smaller than that of the tile to form a battery unit, and the battery unit is sequentially laminated around the battery unit with a spacer interposed between the units facing each other above and below. In a fuel cell in which a separator for forming a fuel gas flow channel and an oxidizing gas flow channel is provided on the front and back sides while partitioning the units, and the fuel cells are stacked in multiple stages, the area of the electrolyte tiles of the battery unit is different in the stacking direction. A large and small battery unit is formed, and an electrolyte tile having a large area is formed so as to protrude from the outer periphery of the spacer, and an electrolyte tile having a small area is formed substantially the same as the outer periphery of the spacer, and the separator is a thin plate. The separator is formed in the center of the separator, and the anode and cathode of the large and small battery units facing each other vertically are formed respectively. Forming a flow path of the wave to be contacted,
An oxidizing gas flow path is formed on the cathode side of the flow path part and a fuel gas flow path is formed on the anode side, and a flat surface portion sandwiched between the electrolyte tile having a small area and the spacer is formed on the inner peripheral side around the separator. On the outer peripheral side together with forming a sealing step portion in contact with the periphery of a large area electrolyte tile, in the portions located on both sides of the flow path portion of the separator, the oxidizing gas inflow and outflow chamber connected to the oxidizing gas flow path A fuel gas inflow / outflow chamber that is formed and connected to the fuel gas flow path is formed.Furthermore, the separator and the large and small battery units located in the inflow / outflow chamber are aligned in the stacking direction, respectively, and are connected to the oxidizing gas inflow / outflow chamber. A fuel cell, characterized in that a supply / exhaust portion comprising a fuel gas supply / discharge port connected to a port and a fuel gas inflow / outflow chamber is formed.