JPH0817452A - Flat plate type fuel cell - Google Patents

Abstract

PURPOSE:To provide a solid electrolyte fuel cell of flat plate type which prevents decreasing an output by providing distribution in supplying air and uniformizing oxygen consumption rate in each part of each cell. CONSTITUTION:A fuel cell has a cell structure of flat plate type arranging a fuel electrode 12 and an air electrode 13 respectively in both surfaces of a solid electrolyte 11 also arranging an interconnector 15, having a flow path 17 as a fluid supply groove of supplying a fluid to these electrodes, respectively in surfaces of these electrodes, to place supplying fuel and air orthogonal to each other. Air, supplied to the interconnector 15 on the air electrode 13 side, is supplied so as to gradually decrease toward the downstream in a flow direction of fuel flowing in a direction orthogonal to the air.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat plate type solid electrolyte fuel cell (SOF) which has a distribution of air supply to make the oxygen consumption rate uniform in each cell and to prevent the output from decreasing.
C: Solid Oxide Fuel Cell).

[0002]

2. Description of the Related Art FIG. 5 shows an example of a flat plate type fuel cell using a conventional solid electrolyte (eg, "yttria-stabilized zirconia (YSZ)"). As shown in the figure, a fuel electrode (for example, Ni / YS) is formed on each side of the solid electrolyte 11.
Z cermet material, etc. 12 and an air electrode (for example, LaS)
rMnO ₃ based material, etc.) 13 to form a cell plate 14, and interconnectors (eg, LaMgCrO ₃ based material or heat resistant alloy) 15 on both sides thereof.
Are sandwiched and stacked to form a bonded body 16. The interconnector 15 has fuel (H ₂ ) or air (oxygen:
Groove-shaped fuel and air flow path 17 for supplying fluid such as O ₂ ).
Are formed in plurality, and gas or air flows in the groove direction.

The interconnector 15 is a cell 14
When a fuel cell stack is formed by stacking the joined bodies 16 while taking out current from the above, the upper and lower joined bodies 16 are electrically connected to each other to prevent mixing of fuel and air.

FIG. 6 shows a perspective view of the basic structure of a flat plate type fuel cell stack. As shown in the figure, generally, the flow paths 17 for supplying a fluid such as fuel (H ₂ ) or air (oxygen: O ₂ ) formed in the interconnector 15 are formed so as to be orthogonal to each other. Therefore, fuel and air are efficiently supplied and exhausted.

[0005]

By the way, when the fuel cell is in operation, fuel and air are consumed by its power generation, so that each component of fuel and air has a partial pressure distribution in the flow direction in the flow path. This is also apparent from the partial pressure distribution chart shown in FIG. 7, which is obtained by calculating the oxygen partial pressure in the air side flow passage by the simulation analysis in the operating state of the flat plate fuel cell.

Further, since the electromotive force of the cell increases as the partial pressure of the fuel gas increases, the current density increases near the fuel inlet (see FIG. 8). Therefore, the oxygen consumption rate on the air side near the fuel inlet increases. In the conventional stack structure as shown in FIG. 6, since air is uniformly supplied to the cell surface, a large amount of oxygen is consumed near the fuel inlet where the current density is high. However, there is a problem in that oxygen is scarcely consumed in the portion where the current density is low near one of the fuel outlets, resulting in a decrease in output.

In view of the above problems, it is an object of the present invention to provide a flat plate type solid electrolyte fuel cell in which the oxygen consumption rate is made uniform in each part of each cell and the decrease in output is prevented.

[0008]

A flat plate fuel cell according to the present invention which achieves the above object has a fuel electrode and an air electrode on both surfaces of a solid electrolyte, and a fluid supply groove for supplying a fluid to these electrodes. In a fuel cell having a flat plate type cell structure in which the interconnectors having the above are respectively disposed on the surfaces of the electrodes, and the supply of fuel and air are orthogonal to each other, the supply of air to the interconnector is orthogonal to the air. It is characterized in that the fuel gradually decreases toward the downstream side in the flow direction of the fuel flowing in the direction.

Further, in the structure of the flat plate fuel cell, the supply of air to each opening of the fluid supply groove formed in the interconnector is gradually made downstream in the flow direction of the fuel flowing in the direction orthogonal to the air. It is characterized in that a diaphragm member that closes so as to decrease is provided.

[0010]

As shown in FIG. 1 showing the concept of the present invention, when the fuel supply and the air supply are introduced orthogonally to each other, more air is made to flow in the vicinity of the fuel inlet, so that oxygen consumption in each part of the cell is increased. The rate is made uniform, and the decrease in output due to lack of oxygen is prevented.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the cell structure according to the present invention will be described below in detail with reference to the drawings.

(First Embodiment) FIG. 2 shows an outline of a first embodiment of the present invention. As shown in the figure, the solid electrolyte 11 is provided on both sides with a fuel electrode (for example, Ni / YSZ cermet material) 12 and an air electrode (for example, LaSrMnO 2).
_A cell plate 14 is formed by adhering the same to a ₃ type material etc. 13 and interconnectors (eg LaM
The bonded body 16 is formed by sandwiching and sandwiching a gCrO ₃ system material or a heat-resistant alloy) 15.

The interconnector 15 is provided with a plurality of groove-shaped fuel and air passages 17 for supplying a fluid such as fuel (H ₂ ) or air (oxygen: O ₂ ). Each of them flows in the groove direction so as to go straight.

At the inlet side of the flow path 17 which is a fluid supply groove formed in the interconnector 15 on the side of the air electrode 13, the flow direction (X) of the fuel flowing in the direction orthogonal to the flow direction of the air (Y direction) (X Direction), a wedge-shaped throttle member 21 is provided so as to gradually reduce the supply of the air, and the amount of air flowing in from the opening of each flow path 17 is determined by the flow direction of the fuel (X direction). We are trying to reduce it toward the downstream.

As a result, a larger amount of air can be made to flow in the vicinity of the fuel inlet, and as shown in FIGS. 7 and 8, the current density in the vicinity of the fuel inlet becomes higher and the air side in the vicinity of the fuel inlet becomes closer. Even if the oxygen consumption rate is high, since the air is excessively supplied on the fuel inlet side, it is possible to make the oxygen consumption rate uniform in each cell surface and prevent the output from decreasing due to insufficient oxygen.

(Second Embodiment) FIG. 3 shows a second embodiment of the present invention, (A) is a plan view thereof, and (B) is a front view thereof. In the present embodiment, the inside of each opening on the inlet side of the flow path 17, which is a fluid supply groove formed in the interconnector 15 on the air electrode 13 side, extends in a direction orthogonal to the air flowing direction (Y direction). Flow direction of flowing fuel (X direction)
To gradually reduce the supply of air toward the downstream of
The throttle members 22 each having a gradually increasing size are provided so that the amount of air flowing in from the opening of each flow passage 17 is decreased toward the downstream side in the fuel flow direction (X direction). There is. Reference numeral 18 in the figure indicates a current collector.

(Third Embodiment) FIG. 4 shows a third embodiment of the present invention. In this embodiment, in the case where the flow passage 17 formed in the interconnector 15 introduces the fuel supply and the air supply orthogonally, the flow passage 17 formed in the interconnector 15 on the air electrode 13 side is An air introduction passage 23 is provided on the inlet side along the opening of the flow passage 17, and the air supplied to the passage 23 is introduced in the same direction as the fuel flow direction (X direction). A large amount of air is supplied into the flow passage 17 near the fuel inlet by gradually reducing the amount of air flowing into the opening of the fuel tank toward the downstream side in the fuel flow direction (X direction) due to the difference in static pressure. I am trying to let you. As a result, it is possible to eliminate the imbalance of the oxygen partial pressure in the cell surface due to the imbalance of the flow rate generated by the slit.

In the present embodiment, the throttle member that inhibits the introduction of air and the air introduction passage due to the static pressure difference are formed so that the amount of air supplied between the fuel inlet and the fuel outlet is orthogonal to the air. Although the fuel is gradually reduced toward the downstream side in the flow direction, the present invention is not limited to this. For example, the width of the air supply passage may be gradually narrowed. Good.

[0019]

As described above in connection with the embodiments, when introducing the fuel supply and the air supply in a direction orthogonal to each other, by causing more air to flow in the vicinity of the fuel inlet, the flow rate imbalance caused by the slit is unbalanced. As a result, it is possible to eliminate the imbalance of the oxygen partial pressure in the cell surface, and as a result, the oxygen consumption in each part of the cell is made uniform and the decrease in output due to lack of oxygen is prevented.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a flat plate type fuel cell of the present invention.

FIG. 2 is a perspective view of the flat-plate fuel cell of Example 1.

FIG. 3 is a schematic diagram of a second embodiment.

FIG. 4 is a schematic diagram of Example 3.

FIG. 5 is a basic structural diagram of a flat plate fuel cell.

FIG. 6 is a perspective view of the basic structure of a flat plate fuel cell.

FIG. 7 is a distribution diagram of oxygen partial pressure in the air flow passage during operation of the flat plate fuel cell.

FIG. 8 is a cell plane current density distribution diagram during operation of the flat plate fuel cell.

[Explanation of symbols]

11 solid electrolyte (for example, YSZ etc.) 12 fuel electrode (for example, Ni / YSZ cermet material etc.) 13 air electrode (for example, LaSrMnO ₃ system material etc.) 14 cell plate 15 interconnector (LaMgCrO ₃ system material or heat resistant alloy etc.) 16 air passages 17 flow passages 18 current collectors 21, 22 throttle members 23 air introduction passages

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Atsushi Kimura 1-3-1, Uchisaiwaicho, Chiyoda-ku, Tokyo Within Tokyo Electric Power Company (72) Kenichiro Kosaka 5-717-1, Fukahori-cho, Nagasaki-shi, Nagasaki Sanryo Heavy Industries Co., Ltd. Nagasaki Research Institute (72) Inventor Seiji Takatsuki 1-1, Atsunoura-machi, Nagasaki-shi, Nagasaki Mitsubishi Heavy Industries, Ltd. Nagasaki Shipyard

Claims (2)

[Claims] 1. A fuel electrode and an air electrode are arranged on both sides of a solid electrolyte, and interconnectors having fluid supply grooves for supplying fluid to these electrodes are arranged on the surfaces of the electrodes, respectively. In a fuel cell having a flat-plate cell structure in which air supplies are orthogonal to each other, the supply of air to be supplied to the interconnector is gradually reduced toward a downstream side in a flow direction of fuel flowing in a direction orthogonal to the air. A flat plate fuel cell characterized by the above. 2. The flat plate type fuel cell according to claim 1, wherein air is supplied to each opening of the fluid supply groove formed in the interconnector toward a downstream side in a flow direction of fuel flowing in a direction orthogonal to the air. The flat plate fuel cell is characterized in that it is provided with a throttle member that closes so as to gradually decrease.