JPH06251796A - Fuel cell - Google Patents

Abstract

PURPOSE:To contribute to realization of large capacity by improving reliability while constituting in such a way that thermal stress-strain is not caused between a housing container and a laminated fuel cell stack, and increasing the number of laminated cells while realizing simplification and compactness of a support structure of the laminated fuel cell stack to the housing container. CONSTITUTION:A lower part fastening plate 9 having a projecting part 9a projecting in the radiant direction is arranged under a laminated fuel cell stack 1, and plural runout preventive parts 13 are arranged in a housing container 10 so as to hold the projecting part 9a slidably in the central direction of the laminated fuel cell stack 1 when the lower part fastening plate 9 is expanded and contacted by thermal expansion. An insulating plate 11 is formed in this runout preventive part 13 so as to insulate the housing container 10 and the laminated fuel cell stack 1 electrically from each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell in which a laminated cell stack is housed in a container, and more particularly to a fuel cell having an improved support structure for the laminated cell stack with respect to the container.

[0002]

2. Description of the Related Art Conventionally, a fuel cell has been known as a device for directly converting the energy released along with the oxidation reaction into electric energy by oxidizing a fuel having chemical energy in an electrochemical process. . A fuel cell is usually constructed by accommodating a laminated cell stack in which unit cells for power generation are laminated in a container.

The unit cells constituting the above-mentioned laminated cell stack are provided with a pair of porous electrodes, a matrix holding an electrolyte is sandwiched between the electrodes, and a fuel gas such as hydrogen is brought into contact with the back surface of one of the electrodes. Then, an oxidant such as air is brought into contact with the back surface of the other electrode, and the electric energy generated by the electrochemical reaction occurring at this time is taken out from between the electrodes. In this case, hydrogen or a reformed gas obtained by reforming natural gas is used as the fuel gas, and air or oxygen is used as the oxidant.
Further, molten carbonate, alkaline solution, acidic solution, solid polymer oxide, etc. are used as the electrolyte retained in the matrix, but recently, phosphoric acid fuel cells using phosphoric acid as the electrolyte have been commercialized. Attention is paid from a viewpoint.

The structure of a conventional fuel cell will be described in detail with reference to FIGS. 8 and 9. 8 and 9 show a schematic configuration of a general fuel cell in a plan view and a side view. In the figure, 1 is a laminated battery stack in which a plurality of unit batteries are stacked, and the laminated battery stack 1 is composed of tie rods 4 and nuts 5 provided at four corners through an upper clamping plate 2 and a lower clamping plate 3. It is tightened and assembled. Reference numeral 6 in the drawing denotes a storage container capable of storing the laminated battery stack 1. At the bottom of this storage container 6 is a circular lower base 6
a is provided. Lower clamping plate 3 and lower base 6
An insulator 7 is fastened and fixed to a by a fastening bolt 8 or the like. The laminated battery stack 1 is formed by the insulator 7.
Are supported while being electrically insulated from the storage container 6.

[0005]

By the way, the electrochemical reaction of the unit cells constituting the laminated battery stack 1 is promoted as the operating temperature is higher. Therefore, the power generation efficiency of the fuel cell basically increases as the operating temperature of the unit cell increases. Therefore, the reaction heat of the laminated battery stack 1 during operation becomes a considerably high temperature. For example, the temperature during operation of the laminated cell stack 1 in a phosphoric acid fuel cell is
It has risen to around 200 ° C. On the other hand, the storage container 6 for storing the laminated battery stack 1 can have a temperature of several 10 ° C. at most. In the fuel cell in which the laminated cell stack 1 and the storage container 6 having such a large temperature difference are connected by the insulator 7, the following problems occur.

That is, when the fuel cell is in operation, a difference in thermal expansion occurs between the laminated cell stack 1 and the lower base 6a of the storage container 6 due to a large temperature difference. For example, in the laminated battery stack 1 having a side length of 1 m, the difference in thermal expansion is 2-3.
It can reach mm. Therefore, the insulator 7 connecting the laminated battery stack 1 and the storage container 6 is subject to thermal stress strain such as shearing, and the insulator 7 may be damaged by this thermal stress strain. In recent years, fuel cells are being made larger in size for practical use, and therefore the difference in thermal expansion between the laminated cell stack 1 and the storage container 6 is widened, and the thermal stress strain applied to the insulator 7 tends to be large. . When the thermal stress strain becomes large, the insulator 7 is easily damaged, and the reliability of the fuel cell is deteriorated.

As described above, the increase in thermal stress strain is a factor that impairs reliability, and the storage container for the laminated battery stack 1 is arranged so as not to generate thermal stress strain between the laminated battery stack 1 and the storage container 6. Fixing in 6 is a big issue. In particular, in order to commercialize a large-scale power generation plant using a charge cell or an on-site plant for private use, strict reliability is required for the fuel cell at present, and the above-mentioned problems are strongly desired to be solved. .

[0008] Further, in order to increase the capacity of the fuel cell, it is required to increase the number of stacked unit cells, but there is a limit to the number of stacked unit cells due to transportation restrictions and stacking operation restrictions. . Therefore, within that limit, the laminated battery stack 1
In order to secure the stacking height of the stack battery to the maximum, it is necessary to simplify and compact the tightening plates 2 and 3 for tightening the unit batteries from above and below and the supporting structure of the stacked battery stack 1 with respect to the storage container 6. . However, the insulator 7 supporting the laminated battery stack 1 in the storage container 6 must have a certain height dimension in order to secure an insulation distance, and moreover, a tightening space for the tightening bolt 8 must be secured.
Therefore, it is very difficult to simplify and make the insulator 7 compact. Therefore, it was difficult to increase the number of stacked unit cells within the limit due to transportation restrictions.

The present invention has been proposed to solve the above-mentioned problems of the prior art, and its object is to prevent thermal stress strain between the storage container and the laminated battery stack. While ensuring excellent reliability,
It is an object of the present invention to provide a fuel cell which can contribute to a large capacity by increasing the number of stacked unit cells by simplifying and downsizing the supporting structure of the stacked cell stack with respect to the storage container.

[0010]

In order to achieve the above object, the fuel cell of the present invention is provided with a stack lower structural member for supporting the laminated cell stack in a storage container at the lower portion of the laminated cell stack. The storage container is provided with a plurality of swing stop portions for slidably holding the stack lower structure member toward the center of the laminated battery stack when the stack lower structure member expands and contracts due to thermal expansion. An insulating plate that electrically insulates between the storage container and the laminated battery stack is formed.

[0011]

In the fuel cell of the present invention having the above-described structure, the laminated cell stack is in an operating state, and a difference in thermal expansion amount occurs between the stack lower structural member on the laminated cell stack side and the storage container. However, since the lower stack structural member slides in the steady-state portion toward the center of the laminated battery stack, thermal stress strain is not applied to the lower stack structural member. Further, even if the lower stack structural member slides due to thermal expansion, the stack lower structural member is held by the plurality of steady rests, so that the laminated battery stack can be reliably fixed in the storage container. Further, since the laminated battery stack and the storage container are insulated from each other by the thin insulating plate, a large-sized insulator unlike the conventional case is not required, and the height of the laminated battery stack can be reduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be specifically described below with reference to FIGS. The same members as those in the conventional example shown in FIGS. 8 and 9 are designated by the same reference numerals, and the description thereof will be omitted.

In this embodiment, as shown in FIGS. 1 and 2, a lower tightening plate 9 is provided as a lower stack structural member in the lower portion of the laminated battery stack 1. Further, the storage container 10 is provided with a base 10a for indicating the laminated battery stack 1, and a receiving seat 10b is provided on the base 10a.
Are formed. Further, the lower tightening plate 9 and the receiving seat 10b
A thin insulating plate 11 is provided between and so as to insulate the both. As shown in FIG. 5, the insulating plate 11 is formed with a notch 11a that can be fitted into the receiving seat 10b and a groove 11b close to the outer periphery. The notch 11a is set to a size larger than the receiving seat 10b.

Protrusions 9a are provided at the four corners of the periphery of the lower tightening plate 9 so as to project radially from the central portion. As shown in FIGS. 3 and 4, the protrusion 9a is covered with an insulator 12 such as a heat resistant resin. Further, on the base 10a of the storage container 10, a steady rest 10c is provided near the protrusion 9a. This seat 1
The steady rest 13 is fastened and fixed on the 0c by a bolt 14. The steady portion 13 has an opening 1 at the center.
3a is formed, and the protrusion 9a covered with the insulator 12 is inserted therein. At this time, the opening 13a
Holds the protrusions 9a from the left and right without clearance. The steady rest 13 is adapted to hold the protrusion 9a slidably toward the center of the laminated battery stack 1 when the lower tightening plate 9 expands and contracts due to thermal expansion.

In the fuel cell of this embodiment having such a structure, when the laminated cell stack 1 is in an operating state,
The difference in the amount of thermal expansion between the lower tightening plate 9 and the base 10a of the storage container 10 occurs in the radial direction from the central portion of the lower tightening plate 9, but the protrusions are different from the steady rests 13 of the respective corners. Since 9a slides toward the center, an unreasonable force is not applied to each member. According to the present embodiment, if the difference in thermal expansion is about 2 to 3 mm, it can be sufficiently absorbed, and it is possible to cope with a laminated battery stack having a side length of 1 m due to the recent size increase. Further, even if the lower tightening plate 9 slides toward the center, since the plurality of steady rests 13 are arranged in the peripheral portion, it can be securely fixed as a whole. Moreover, since the opening 13a holds the protrusion 9a from the left and right without clearance,
In each protrusion 9a, the opening 1 of the steady portion 13 is provided for the horizontal runout orthogonal to the central direction of the lower tightening plate 9.
3a can restrain this.

Further, the laminated battery stack 1 is insulated and supported by the insulating plate 11, and simply the receiving seat 10b on the base 10a.
Since it is simply fitted into the insulator, it is possible to significantly reduce the height of the laminated battery stack as compared with the insulator 7 in the conventional example. Moreover, by providing the groove 11b in the vicinity of the outer circumference, it is possible to secure a desired insulation surface distance. Further, since the insulating plate 11 may have a structure that simply supports the load, it can have a simple structure.

As described above, according to the fuel cell of the present embodiment, excellent reliability is ensured by the structure in which thermal stress strain is not generated between the laminated cell stack 1 and the storage container 10. I was able to. At the same time, the height of the supporting structure of the laminated battery stack 1 was reduced, which contributed to the increase in the capacity by increasing the number of laminated single cells.

The present invention is not limited to the above-mentioned embodiment, but includes other embodiments as shown in FIGS. 6 and 7. That is, at the four corners around the lower tightening plate 9, cutout grooves 9b are provided in the radial direction from the central portion, and an insulating steady portion 16 insulated by an insulator 15 such as a heat resistant tree is attached to the receiving seat 10c. It is also possible to provide a highly reliable large-capacity fuel cell having the same effect as described above by tightening and fixing the same with the bolt 14. Although not shown, if the groove is a groove notched in the radial direction from the center portion, the position is not limited to the four corner portions around the lower tightening plate, and may be any position on the periphery.

[0019]

As described above, according to the present invention,
The unit cell is configured so that thermal stress strain is not generated between the storage container and the laminated battery stack to ensure excellent reliability, and the supporting structure of the laminated battery stack with respect to the storage container is simplified and compacted. It was possible to contribute to the large capacity by increasing the number of laminated layers.

[Brief description of drawings]

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

FIG. 2 is a side view showing an embodiment of the fuel cell of the present invention.

FIG. 3 is a partial plan view of a corner portion of a lower tightening plate showing an embodiment of the fuel cell of the present invention.

FIG. 4 is a partial side view of a corner portion of a lower tightening plate showing an embodiment of the fuel cell of the present invention.

FIG. 5 is a partial side view of a corner portion of a lower tightening plate showing an embodiment of the fuel cell of the present invention.

FIG. 6 is a partial plan view of a lower tightening plate corner portion showing another embodiment of the fuel cell of the present invention.

FIG. 7 is a partial side view of a corner portion of a lower tightening plate showing another embodiment of the fuel cell of the present invention.

FIG. 8 is a plan view showing an example of a conventional general fuel cell.

FIG. 9 is a side view showing an example of a conventional general fuel cell.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Laminated battery stack 2 ... Upper clamping plate 3 ... Lower clamping plate 4 ... Tie rod 5 ... Nut 6 ... Storage container 7 ... Insulator 8 ... Fastening bolt 9 ... Lower clamping plate 9a ... Projection part which protrudes in radial direction 9b ... Notch groove in radial direction 10 ... Storage container 10a ... Base 10b ... Receiving seat 10c ... Resting part receiving seat 11 ... Insulating plate 11a ... Notch 11b ... Groove 12 ... Heat-resistant tree etc. Stop portion 14 ... Bolt 15 ... Insulator such as heat resistant tree 16 ... Insulation steady portion

Claims (1)

[Claims] 1. A fuel cell in which a stacked cell stack in which a plurality of unit cells are stacked is housed in a storage container, and a stack lower structural member that supports the stacked cell stack from below is provided at the bottom of the stacked cell stack. The storage container is provided with a plurality of swing stop portions that slidably hold the stack lower structural member toward the center of the laminated battery stack when the stack lower structural member expands and contracts due to thermal expansion. The fuel cell is characterized in that an insulating plate that electrically insulates between the storage container and the laminated cell stack is formed in the fuel cell.