JPH11111324A - Gas insulation device direct connection type fuel cell - Google Patents

Abstract

(57) [Problem] To provide a large-capacity gas insulation device directly-coupled fuel cell in which the size of the entire power generation system is significantly reduced. A fuel cell directly connected to a gas insulating device has a configuration in which an electrolyte layer, a catalyst, a cooling plate, and the like are sandwiched between a fuel electrode and an air electrode, and generates power by flowing hydrogen and air to the fuel electrode and the air electrode, respectively. Are connected in series so as to be electrically parallel to each other to form one unit cell. A large number of cells of this one unit are connected in series and stored in a gas insulated conduit.
A large-capacity fuel cell is formed by connecting a large number of cells in a single unit in series, and is further integrated with gas-insulated equipment via a gas-insulated conduit. A fuel cell directly connected to the insulating device can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell for generating electricity using hydrogen and oxygen as fuel, and has a large capacity by arranging unit cells in series and parallel, and is directly connected to a gas insulating device for further miniaturization. The present invention relates to a fuel cell directly connected to a gas insulating device.

[0002]

2. Description of the Related Art A fuel cell is a device that oxidizes chemical energy of a fuel in an electrochemical process, thereby directly converting energy released by the oxidation reaction into electric energy. A power plant using this fuel cell has a thermal efficiency of 40 to 50 for power generation even on a relatively small scale.
%, And is expected to far surpass advanced thermal power plants. In addition, the emission of SO _x and NO _x , which are pollution factors that have become a major social problem in recent years, is extremely low.
Since the power generator does not include a combustion cycle, it does not require a large amount of cooling water and has low vibration noise, so high energy conversion efficiency can be expected in principle, and there are few environmental problems such as noise and exhaust gas, and load fluctuations Due to its characteristics such as good responsiveness, full-scale practical application is expected.

FIG. 6 is an exploded perspective view showing a configuration example of a unit cell of a fuel cell using phosphoric acid as an electrolyte. In the figure, reference numeral 22 denotes an electrolyte layer formed by impregnating a matrix with phosphoric acid as an electrolyte;
Are an anode electrode and a cathode electrode made of a porous carbon material interposed therebetween. Both electrodes 21 and 23 have grooves 27 and 28 on the back side, respectively, through which fuel gas and oxidizing gas flow. Here, a plurality of grooves 27 through which the fuel gas flows and a plurality of grooves 28 through which the oxidizing gas flows are regularly formed in a direction orthogonal to each other.

A unit cell is formed by the above-described structure, and a plurality of such unit cells are stacked with separators 20 and 24 made of dense carbonaceous material interposed therebetween to constitute a unit cell stack. Further, heat of reaction is generated in the unit cell, and this heat causes an excessive chemical reaction in the unit cell,
As a result, this is a factor that lowers the power generation capacity. Cooling is required to prevent this. Generally, a plurality of cooling pipes 26 are arranged on the cooling panel 25 for cooling. The cooling panel 25 is provided every time a plurality of unit cells are stacked.

By the way, in order to incorporate a fuel cell as a new energy source into current power demand, a large-sized device which outputs a large amount of power is required and required. Since the power generation voltage of the unit cell of the fuel cell is about 1.0 V / sheet, it is necessary to increase the area of the cell itself and the reaction area in order to obtain a large power (large). Creating conditions for obtaining current). Further, in order to generate a high voltage, it is necessary to increase the number of stacked unit cells. Various measures have been devised to achieve these measures, but the problem of drift (current flows unbalanced) due to the large cell area and the degree of cooling by stacking cells in each cell However, there was a problem that the fuel cell was unbalanced, and it was difficult to obtain a high-power fuel cell.

In addition, the conventional fuel cell power generation system, particularly the equipment after the battery output terminal, has a low generated voltage and is of the air insulation type. This form of insulation may lead to an increase in space and inconvenience as the output of the fuel cell increases in the future. Therefore, it is fully conceivable that there will be a demand for downsizing of the fuel cell power generation system in the near future, and it is necessary to deal with this.

[0007]

Fuel cells have many advantages and are expected to be a new energy source. However, as described above, it is necessary to increase the reaction area of the cell and increase the number of stacked cells in order to obtain large power.

Here, in order to increase the reaction area of the cell, it is necessary to increase the area of the cell itself. The cell has a configuration in which an electrolyte layer made of phosphoric acid and a catalyst layer are sandwiched between electrodes (carbon). In this configuration,
Ideally, the thicknesses of the electrolyte layer and the catalyst layer between the electrodes are uniform over the entire surface, that is, the same chemical reaction is performed on the entire surface between the electrodes. However, in practice, it is difficult to make the thicknesses of the electrolyte layer and the catalyst layer between the electrodes uniform over the entire surface, which is a key point in cell production. Of course, the larger the cell area, the more difficult this is.

When the thicknesses of the electrolyte layer and the catalyst layer between the electrodes are uneven, the current density distribution on the cell surface which is proportional to the reaction becomes uneven. This is shown in FIG. The current distribution on the surface of the cathode 23 in FIG.
Shown in FIG. 7B shows the current density of each part. According to this figure, the current density of the portion (a) is significantly higher than that of the other portions. In this state, the reaction is partially excessive, and partial damage and a short life are caused by heat and the like. That is, the life of the cell becomes extremely short.

Further, in order to obtain a high voltage, it is necessary to increase the number of stacked cells. However, if the number of cells is increased, the temperature distribution of the cells becomes uneven. This is shown in FIG. As shown in FIG. 3A, a cooling plate 30 for cooling the cells is provided substantially in the middle of the cells 31 stacked in multiple stages. The temperature distribution of each cell in this state is shown in FIG. According to this figure, the temperature of the cells closer to the cooling plates 29 and 30 is lower, and the temperature of the cells farther from the cooling plates 29 and 30 is higher. When the cell temperatures are different, the chemical reaction of the cell becomes non-uniform, and the life of the cell varies. In order to make the cell temperature uniform, it is necessary to increase the number of cooling plates 30 with respect to the number of cells, but this leads to an increase in the number of parts, an increase in cell height, etc., leading to an increase in device dimensions and an increase in cost.

Further, as described above, the devices after the conventional fuel cell output terminal are of the air insulation type, and it is expected that the space will be expanded as the output of the fuel cell increases in the future. In order to meet the demands in the near future, it is necessary to reduce the size. As described above, it is difficult for the conventional fuel cell configuration to cope with high power use, and there are many problems to be solved.

SUMMARY OF THE INVENTION The present invention has been made to address the above-mentioned problems of the conventional fuel cell, and has as its object the direct connection of a large-capacity gas insulating device in which the size of the entire power generation system is greatly reduced. It is to provide a fuel cell.

[0013]

According to a first aspect of the present invention, there is provided a fuel cell directly connected to a gas insulating device, comprising an electrolyte layer, a catalyst, a cooling plate and the like interposed between a fuel electrode and an air electrode. And a fuel cell that generates hydrogen by flowing hydrogen and air to the fuel electrode and the air electrode, respectively,
A large number of cells are connected so as to be electrically in parallel to form a unit cell, and a large number of the unit cells are connected in series and housed in a gas-insulated conduit to form a unit. Are connected in series to form a large-capacity fuel cell, and are further integrated with gas-insulated equipment via the gas-insulated conduit.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of one unit of a fuel cell according to one embodiment of the present invention. In the drawing, reference numeral 1 denotes a unit cell in which small cells are electrically connected in parallel. A large number of the unit cells 1 are connected in series and stored in a gas-insulated conduit 2. One unit of fuel cell is used. For convenience of description, this one-unit fuel cell is composed of three one-unit cells 1, but the number is not particularly limited.

In this embodiment, air and fuel gas flow as described below. The air to be sent to the cathode is a valve 8a
Through the gas-insulated conduit 2 containing the fuel cell, flows through one end of the gas-insulated conduit 2, passes through one unit of cells inside the conduit, and then is sent to the next unit of cells located next to it. Flows out of the valve 8b at the other end through the inside of all the cells in the gas-insulated pipeline 2. In addition, the hydrogen gas flowing into the fuel electrode passes through the valve 7a, flows in from the side surface of the portion near the one end face of the gas insulated conduit 2, passes through one unit cell inside the gas insulated conduit 2, and faces each other. Spilled to the side, and furthermore pipe 4a
Alternatively, the gas is sent to the next unit cell connected in series via 4b, and finally passes through all the cells inside the gas insulated conduit 2, and is discharged to the side of a part of the side facing the inflow port. You. As described above, the air and the fuel (hydrogen) are
Flows along a path in which a large number of cells 1 in one unit are connected in series.

A unit of cells 1 is connected to each other by an insulator 6 having a diameter through which cooling water can pass to make the cooling system linear, and one end of the gas-insulated pipe 2 is connected to the other unit. The cooling water is caused to flow linearly to the end face side, and the cooling water flowing linearly in this manner can reduce the piping loss of the cooling water system. 9a and 9b are DC output lines, 1
0a and 10b are output terminals, and 50a and 50b are air connection pipes.

FIG. 2 is an internal configuration diagram of one unit cell of FIG. 1 as viewed from the line AA. As shown in the figure, one unit cell has a configuration in which an electrolyte layer, a catalyst, a cooling plate, etc. are sandwiched between a fuel electrode and an air electrode, and it is not possible to generate electricity by flowing hydrogen and air to the fuel electrode and the air electrode, respectively. It is based on the conventional power generation principle. In the present embodiment, the small cells 11 are electrically connected in parallel. The electrodes 14, 1
5 are arranged on both sides, and the electrodes 12 and 13 of the small cell 11 are connected to the electrodes 14 and 15, respectively. By connecting the small cells 11 in the same manner, a cell area corresponding to the parallel arrangement of the cells 11 is formed between the electrodes 14 and 15. The fuel cell having such a cell configuration is disposed in a gas insulating pipe 17 provided with fuel connection pipes 4a and 4b. Although the cell area is large due to such a cell configuration,
Since a cell configuration having a small cross-sectional area can be formed, a current drift phenomenon caused by a conventional large cell cross-sectional area can be eliminated.

Further, as shown in FIG.
6 is disposed so as to be located substantially at the center of one unit cell,
By cooling the center of the stacked cells, uneven cooling of each cell 11 can be reduced as shown in FIG. 4B (the outer cells have good heat radiation characteristics, so that the cooling plate 16 can be almost equal to the unit cell). It can be balanced by providing it in the center).

As described above, according to the fuel cell of this embodiment, it is possible to eliminate the current drift phenomenon and the non-uniformity of the cell temperature distribution as in the conventional fuel cell. A large-capacity fuel cell can be obtained.

FIG. 3 is a configuration diagram of a large-capacity fuel cell device according to another embodiment of the present invention. As shown in the figure, in this embodiment, a large-capacity fuel cell can be formed relatively easily by connecting a large number (51a, 51b, 51c) of one unit of fuel cell housed in a gas-insulated conduit in series. can do. 9a and 9b are DC output lines, 10a and 10b
Is an output terminal.

FIG. 4 is a structural view of a fuel cell directly connected to a gas insulating apparatus according to still another embodiment of the present invention. As shown in the figure, one unit of the fuel cell 40 housed in the gas insulated conduit and the AC / DC converter 42 are connected by a connecting pipe 41, and the AC / DC converter 42 and the gas insulated transformer 44 are connected by a connecting pipe 43. The gas-insulated transformer 44 and the gas-insulated switchgear 46
Are connected by a connecting pipe 45, and the gas insulated switchgear 46 and a bushing device including a bushing pocket 47 and a bushing 48 are connected by a tube to form an integral structure. Further, a bushing 48 is connected to a high voltage lead wire 49. With such an arrangement, it is possible to provide a reduced-capacity, high-capacity gas-insulation-device-direct-connection fuel cell.

[0022]

As described above, according to the present invention,
A large-capacity fuel cell with uniform temperature distribution and current distribution can be obtained by connecting small-area cells in parallel. You can get a battery.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of one unit of a fuel cell according to the present invention.

FIG. 2 is an internal configuration diagram of one unit cell from AA in FIG. 1;

FIG. 3 is a diagram showing a series connection of one unit in the fuel cell of the present invention.

FIG. 4 is a configuration diagram of a gas-insulated fuel cell device according to an embodiment of the present invention, in which a fuel cell and a gas-insulated device are directly connected.

FIG. 5 is a diagram showing a temperature distribution inside one unit cell in the fuel cell of the present invention.

FIG. 6 is an exploded perspective view of a unit cell of a conventional fuel cell.

FIG. 7 is a diagram showing a current density distribution on a cell of a conventional fuel cell.

FIG. 8 is a diagram showing non-uniformity of temperature distribution of a conventional fuel cell.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... 1 unit cell, 2 ... Gas insulation pipe, 3 ... Potential connection line, 4a, 4b ... Fuel connection pipe, 5 ... Insulation gas in pipe, 6 ... Cooling water pipe, 7a ... Fuel inlet valve , 7b
... Fuel outlet valve, 8a ... Air inlet valve, 8b ...
Air outlet valves 9a, 9b: DC output lines, 10a, 1
0b: output terminal, 11, 31, cell, 12, 13, electrode, 14, 15: potential fixing plate, 16, 29, 30, cooling plate, 17: gas-insulated conduit, 20, 24: separator, 2
DESCRIPTION OF SYMBOLS 1 ... Anode electrode, 22 ... Electrolyte layer, 23 ... Cathode electrode, 25 ... Cooling panel, 26 ... Cooling pipe, 27, 28 ...
Groove, 40: fuel cell, 41, 43, 45: connecting pipe, 42
... AC / DC converter, 44 ... Transformer for gas-insulated converter, 46 ...
GIS, 47: bushing pocket, 48: bushing, 49: high-voltage lead wire, 50a, 50b: air connection pipe, 51a, 51b, 51c: one unit fuel cell.

Claims (1)

[Claims] 1. A fuel cell comprising an electrolyte layer, a catalyst, a cooling plate and the like sandwiched between a fuel electrode and an air electrode, and generating electricity by flowing hydrogen and air through the fuel electrode and the air electrode, respectively. And connect them in parallel so that
A unit cell, a large number of the unit cells are connected in series and stored in a gas insulated conduit to form a unit.
A large-capacity fuel cell is formed by connecting a large number of unit batteries in series, and further integrated with a gas-insulated device via the gas-insulated conduit.