JPH0557713B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a fuel cell having an improved seismic structure.

[Technical Background of the Invention] A fuel cell is a device that directly converts the energy released in the oxidation reaction into electrical energy by oxidizing the chemical energy of fuel through an electrochemical process. Even on a relatively small scale, a power generation plant using fuel cells can achieve a thermal efficiency of 40 to 50%, and is expected to far outperform new thermal power plants. Furthermore, SOx and Nox, which are pollution factors that have become major social problems in recent years,
Emissions are extremely low, and since there is no combustion cycle within the power generation equipment, large amounts of cooling water are not required.
In principle, high energy conversion efficiency can be expected, such as low vibration noise, and there are few environmental problems such as noise and exhaust gas.Furthermore, it has features such as good responsiveness to load fluctuations, so its development, There are expectations and interest in research for practical application.

A small-scale fuel cell power generation plant of this type has already been prototyped and is now in the experimental operation stage. However, the biggest key to the practical application of large-capacity fuel cell power generation plants is to reduce costs by increasing the unit capacity of the fuel cell as much as possible, and to reduce the seismic performance of the fuel cell contents that occurs as the size increases. It depends on how to prevent this, and how to evenly maintain the tightening force on the cell stack during transportation or after installation on site, thereby extending the life of the fuel cell.

Now, a cross-sectional model diagram showing the principle of such a fuel cell is shown in FIG. That is, a set of porous electrodes 1
During this time, an electrolyte layer 2 impregnated with an electrolytic solution such as phosphoric acid is interposed to form a cell, and hydrogen gas H and air A are continuously supplied to both end faces of the cell.
In this way, the reaction products and reaction residues L are continuously removed to the outside, so power generation can be continued for a long period of time.

Further, the basic configuration of such a fuel cell is as shown in FIG. 2. That is, a positive electrode 4 and a negative electrode 5 are arranged on both sides of an electrolyte matrix layer 3 to form a square plate-shaped unit cell, and in order to use this unit cell as a power generation device, a large number of unit cells are connected in series. Interconnectors 6 having grooves for supplying gas are disposed between these unit cells and are stacked alternately with the unit cells. This grooved interconnector 6
is provided with a plurality of grooves opening on two opposing side edges, a hydrogen gas flow path 7 using the groove on one side as a flow path, and an air flow path 8 using the groove on the other side as a flow path.
are arranged in directions perpendicular to each other.

By the way, in the fuel cell N currently under development, as shown in FIGS. 3A and 3B, a cell stack 9 is constructed by stacking a plurality of the above-mentioned single cells in the shape of a rectangular column, and the cell stack 9 is constructed by stacking a plurality of cells as described above in the shape of a rectangular column. A manifold 10 for supplying reaction gas is attached. Each of these My Folds 10 has a hydrogen gas supply pipe 1.
1. A hydrogen gas exhaust pipe 12, an air supply pipe 13, and an air exhaust pipe 14 are connected, and hydrogen gas and air are designed to flow in the directions of arrows A and B within the cell stack 9. Also, cell stack 9
Although a higher operating temperature is preferable in terms of reaction theory,
Due to constraints such as the heat resistance of the constituent materials and the vapor pressure of the electrolyte,
It is desirable to maintain the temperature around 200℃. Therefore,
Cooling water is circulated in a conduit buried in the cell stack 9 to cool the heating at the time of starting the fuel cell and the heat generated during operation. That is, in this type of fuel cell, as shown in FIG. 3A, a cooling water supply pipe 15 and a cooling water discharge pipe 16 are arranged, and the cooling water circulates within the cell stack 9 as shown by the broken line C. There is.
Furthermore, the output of the fuel cell is direct current, and power terminals (positive electrodes) 17 disposed at the upper and lower ends of the cell stack 9,
The power is drawn out from the power terminal (negative electrode) 18 through the connection conductor 19 and bushing 20 to the outside of the tank 21 .

Further, cross-shaped clamping plates 22 are arranged at the upper and lower parts of the cell stack 9, and clamping metal fittings 23 having spring mechanisms provided at the four ends of the clamping plates 22 are provided.
The upper and lower clamping plates are tightened by the screws, and the stacked cells are fixed from above and below.

The contents of the fuel cell as described above are housed in a tank 21, and nitrogen gas or the like is sealed in the tank 21 to suppress leakage of reaction gas from the manifold 10 or the like.

[Problems with Background Art] Incidentally, in the fuel cells shown in FIGS. 3A and 3B, the unit capacity is proportional to the unit cell area and the number of stacked units. However, the porous electrode plates that make up single cells have the disadvantages of manufacturing savings by molding them to a uniform thickness over the entire surface, and constraints on lamination work because they are made of brittle materials. It is difficult to significantly increase the area due to constraints such as difficulty in stacking cells, and there is a limit to the number of stacked cells due to transportation constraints or stacking work constraints. Capacity is 200~
It is suppressed to 500Kw. Therefore, in order to put a large-capacity thermal energy cell power generation plant into practical use, it is necessary to install several tens or hundreds of fuel cells.

However, in conventional fuel cells, the capacity is increased by increasing the area of the single cells constituting the cell stack as much as possible and by increasing the number of stacked cells. If only the lower part of the cell stack 9 is fixed to the tank 21, the upper part of the cell stack 9 will shake violently due to acceleration and impact during transportation, or earthquakes after installation on site, causing the cell stack 9 to become high. The surface pressure fluctuates extremely on the lower laminated surface. Therefore, in order to prevent such a phenomenon, it is necessary to provide a steady rest device that fixes the contents of the fuel cell to the tank. in this case,
If the cell stack 9 is fixed at the lower part and also fixed to the tank 21 at the upper part, it will be completely protected against vibration.
When attempting to fasten the upper parts of the tank 21 to each other with bolts, the tank 21 is cut vertically at the upper part of the tank 21, a body joint flange is provided at the cut part, and after the bolt tightening work between the tank 21 and the cell stack 9 is completed, the body is reattached. Tanks cut vertically must be connected by tightening joint flanges with bolts, etc., resulting in high costs. In addition, even if a spacer is installed between the cell stack and the tank, there will be a slight gap due to dimensional tolerances, which may cause damage to the structure due to vibration and shock during transportation, or fluctuations in the surface pressure of the cell stack that should be kept constant. This leads to a decrease in electrical output, quality, and lifespan.

Moreover, since a large-capacity power generation device is constructed by connecting a plurality of fuel cells in series, the cell potential becomes high. Therefore, it is necessary to make the potential at the top or bottom of the cell stack and the manifold and clamping plate attached to the cell stack the same potential, so a steady rest structure with high dielectric strength is required between these members and the tank. ing.

[Objective of the Invention] The present invention was proposed to solve the above-mentioned drawbacks, and its purpose is to provide sufficient steady-rest effect and insulation performance without complicating the tank structure, and to extend the service life of the tank. Our goal is to provide high quality fuel cells for a long time.

[Summary of the Invention] The fuel cell of the present invention includes a plurality of rectangular flat unit cells stacked in a square column shape with an electrolyte layer interposed between a pair of electrodes, and a plate is disposed on the top. In a fuel cell in which a cell stack is constructed by integrally fastening the cell stack with upper and lower clamping plates, and this cell stack is housed in a tank, jack bolts are arranged in the center of each of the four sides of the plate, facing toward the tank. On the other hand, a support plate and an insulator are provided on the inner wall of the tank facing the jack bolt, a hand hole formed at the top of the tank is opened, and each jack bolt is brought into contact with each insulator, The jack bolt provides a sufficient steadying effect, and the insulator provides insulation performance.

[Embodiment of the Invention] Next, an embodiment of the present invention will be specifically described based on FIGS. 4 and 5. Note that the same members as those of the conventional type shown in FIGS. 1 to 3 are denoted by the same reference numerals, and explanations thereof will be omitted.

In this embodiment, the cell stack 9 is constructed by stacking unit cells in the shape of a rectangular column, disposing a contact plate 28 on the top, and integrally fastening the stacked body with upper and lower clamping plates. Jack bolts 24 are arranged at the center of each of the four sides, facing toward the tank 21. On the other hand, in the upper part of the tank 21, an inner wall portion facing the jack bolt 24 has a cross-sectional shape of L.
A letter-shaped support plate 25 is provided, and this support plate 2
An insulator 26 is disposed on the vertical surface of 5, and the tip of the shovel bolt is in contact with this insulator 26. Furthermore, a hand hole 27 large enough to operate these shovel bolts 24 is formed at the top of the tank 21.

The positional relationship between this steady rest structure and the clamping plate 22 and clamping metal fittings 23 of the conventionally used cell stack 9 is such that they do not collide with each other, as shown in FIG. That is, the cross-shaped clamping plate 22 has its tip extending in the diagonal direction of the square cell stack, while the steady rest structure of the present invention is arranged at the center of the four sides of the cell stack 9. There is.

In the fuel cell of the present invention constructed in this way, when covering the tank 21, loosen the four jack bolts 24 provided at the center of the four sides of the cover plate 28 of the cell stack 9, and separate it from the insulator 25. After covering the tank 21, the jack bolt 24 is extended and brought into contact with the insulator 26 to prevent the cell stack 9 from swaying.

Therefore, even if the tank shakes a little when covering the tank, it will not collide with the jacket bolt, and there is no risk of deformation or damage to the tank.

In addition, after the tank has been covered, the jack bolt is tightened and brought into contact with the insulator to prevent sway, so there is no possibility of the jack bolt colliding with the tank even when the horizontal load is relaxed.
There is no risk of the tank deforming. Note that since these operations are performed by opening the hand hole 27 provided at the top of the tank 21, fine adjustments are also possible.

As described above, since the jack bolts 24 are in contact with the insulators 26 in all four directions, they have a sufficient stabilizing effect against acceleration and impact during transportation or earthquakes after installation on site. In addition, insulator 2
6, insulation properties are also maintained. Furthermore, since the stability is improved, there is no sudden change in the tightening force of the fuel cell, and a decrease in the efficiency of the output electrical energy can be prevented. Furthermore, even when the cell stack 9 expands and contracts in the vertical direction due to thermal cycles, the jack bolt 24 and the insulator 26 slide up and down at their joint surfaces, so the insulator 26 is not subjected to bending force and the cell stack 9 is also tightened. It is not subject to changes in force.

[Effects of the Invention] As described above, according to the present invention, a tank can have a sufficient steadying effect and insulation performance against acceleration and impact during transportation, or against earthquakes after installation on site, without complicating the tank configuration. Our goal is to provide high quality fuel cells with a long lifespan.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional model diagram showing the principle of a fuel cell, Fig. 2 is a perspective view showing the basic structure of a fuel cell, and Fig. 3A is a plan view showing a schematic structure of a fuel cell that is currently being developed locally. Figure 3B is a longitudinal sectional view of the
The figure is a longitudinal sectional view showing one embodiment of the fuel cell of the present invention, and FIG. 5 is a plan view thereof. N... Fuel cell, 1... Porous electrode, 2... Electrolyte layer, 3... Electrolyte matrix layer, 4... Positive electrode, 5... Negative electrode, 6... Grooved interconnector, 7
...Hydrogen gas flow path, 8...Air flow path, 9...Cell stack, 19...Manifold, 11...Hydrogen gas supply pipe, 12...Hydrogen gas discharge pipe, 13...
Air supply pipe, 14...Air discharge pipe, 15...Cooling water supply pipe, 16...Cooling water discharge pipe, 17...Power terminal (positive electrode), 18...Power terminal (negative electrode), 19...
... Connection conductor, 20 ... Bushing, 21 ... Tank, 22 ... Tightening plate, 23 ... Tightening metal fitting, 24 ...
... Jacket bolt, 25 ... Support plate, 26 ... Insulator, 27 ... Hand hole, 28 ... Plate.

Claims (1)

[Claims] 1. A plurality of rectangular flat unit cells are stacked in a square column shape with an electrolyte layer interposed between a pair of electrodes, a plate is placed on the top, and the stacked body is integrated with upper and lower clamping plates. In a fuel cell in which the cell stack is fastened to form a cell stack and the cell stack is housed in a tank, jack bolts that can move forward and backward toward the side of the tank are disposed at the center of each of the four sides of the plate,
A support plate is provided at the top of the tank at a position facing the jack bolt, an insulator is disposed on the support plate, and the tip of the jack bolt contacts, and a hand hole for operating the jack bolt is formed at the top of the tank. A fuel cell characterized by: