JPH09259916A - Fastening device for fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fastening device excellent in assembly workability further with no deviation in a pressing unit, by providing a pressure seat into point or line contact in a curved surface part between a pressure plate arranged above/under a stack and the pressing unit arranged in an upper/lower side of this pressure plate. SOLUTION: Pressure plates 35a, 35b are arranged respectively in an upper/ lower side of a stack 31 of a fuel cell, further, in an upper/lower side thereof, pressing units 32a, 32b comprising a pressure beam are respectively arranged. This pressing unit 32a, 32b is fastened by a fastening unit 50 comprising a fastening rod 33 inserted thereto, nut 34 and a pressure spring 37, the stack 31 is interposed through the pressure plates 35a, 35b. In a fastening device for the fuel cell, between the pressure plate 35a, 35b and the pressing unit 34, for instance, a pressure seat 38 having a semipherical-shaped curved surface part 38a is arranged in suitable quantity, to be brought into point contact with the pressure plate or pressing unit. This curved surface part is formed in a semicircular cylindrical shape, line contact is attained, or the pressure seat is formed in a spherical shape, to be made capable of also coming into point contact with both the pressure plate and the pressing unit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell tightening device for tightening a stack in which cells are stacked.

[0002]

2. Description of the Related Art FIG. 8 is a side view of a conventional fuel cell tightening device disclosed in Japanese Unexamined Patent Publication No. 1-211868. The fuel cell tightening device is arranged above and below a molten salt type stack 1. An upper holding plate 2a, a lower holding plate 2b, which are respectively arranged,
A tightening rod 3 penetrating the four corners of the upper pressing plate 2a and the lower pressing plate 2b, a nut 4 screwed to the upper and lower parts of the tightening rod 3, and a compression member between the upper pressing plate 2a and the nut 4. The pressure spring 7 provided, the upper pressure plate 5a and the lower pressure plate 5b that sandwich the stack 1 from above and below, between the upper pressure plate 5a and the upper pressure plate 2a, and between the lower pressure plate 5b and the lower pressure plate. Board 2
It is provided with an upper hollow body 6a and a lower hollow body 6b in which a porous heat insulating material is housed in a hermetically sealed hollow portion which is arranged between the hollow body 6b and the hollow body 6b. The tightening rod 3, the nut 4, and the pressing spring 7 form a tightening body 8.

FIG. 9 is a block diagram of the stack 1 of FIG. 8, FIG.
9 is a perspective view of the separator plate of FIG. 9, and the stack 1 is
It has a plurality of cells 10 and a fuel gas supply part 11a and an oxidizing gas supply part 11b which are interposed between the cells 10 and form a fuel gas flow path 13 and an oxidizing gas flow path 14 with the cell 10. A separator plate 11, a corrugated plate 12 disposed in the fuel gas flow path 13 and the oxidizing gas flow path 14,
The stack 1 is provided with a seal portion 21 which is provided in the peripheral portion of the stack 1 and forms the gas passage 18. The cell 10 is provided with an electrolyte layer 15 in which molten carbonate is impregnated as an electrolyte, an anode electrode 16 provided on the fuel gas flow path 13 side of the electrolyte layer 15, and an oxidizing gas passage 14 side of the electrolyte layer 15. And a cathode electrode 17.

In the above fuel cell, the fuel gas 19 is supplied to the anode electrode 16 through the fuel gas flow path 13, and the oxidizing gas 20 is supplied to the cathode electrode 17 through the oxidizing gas flow path 14, thereby making the anode electrode 16 and the cathode electrode Electric power is generated by the potential difference generated between the electric power generator 17 and the electric motor 17.

If the peripheral portions of the upper holding plate 2a and the lower holding plate 2b are simply tightened by the pressure spring 7, the middle portion of the upper holding plate 2a and the lower holding plate 2b bends in the direction away from the stack 1. It deforms, and the surface pressure of the central portion becomes lower than that of the peripheral portion of the stack 1, so that the entire surface of the stack 1 cannot be clamped uniformly. Therefore, in the above-described fuel cell tightening device, the lowering of the surface pressure at the central portion of the stack 1 is prevented by the upper hollow body 6a and the lower hollow body 6b having flexibility such that the internal pressure is constant at any portion. .

[0006]

In the tightening device for a fuel cell having the above-described structure, the hollow bodies 6a and 6b disposed inside the upper and lower holding plates 2a and 2b are used to make the entire stack 1 uniform. Although pressure is applied to improve the cell performance of the fuel cell and to prevent a decrease in power generation efficiency due to gas leakage at the seal portion 21, in order to uniformly press the entire surface of the stack 1, the upper pressing plate 2a and the upper pressing plate are provided. Since the hollow bodies 6a and 6b are provided between the lower pressing plate 2b and the lower pressing plate 2b, respectively, there is a problem that the entire structure becomes large. Also, the hollow body 6
Since a and 6b have a closed structure in which a porous heat insulating material is housed in the hollow portion, it takes time and labor to manufacture the hollow body 6 having a closed structure, and there is also a problem that the manufacturing cost increases.

An object of the present invention is to solve the above-mentioned problems, and has a simple structure, without increasing the size, and at low cost, for uniformizing the surface pressure to the stack. An object of the present invention is to obtain a fastening device for a fuel cell that can be used.

It is another object of the present invention to provide a fastening device for a fuel cell in which the physical strength of the pressing body does not decrease due to the influence of heat from the stack.

Another object of the present invention is to provide a fuel cell tightening device which improves the workability of assembling the fuel cell and prevents the displacement of the pressing body during operation of the fuel cell.

[0010]

A fastening device for a fuel cell according to the present invention includes pressure plates arranged on the upper side and the lower side of a stack, and pressure plates arranged on the upper side and the lower side of these pressure plates. Pressing bodies, tightening bodies that penetrate the corners of these pressing bodies and sandwich the stack with the pressing bodies, and curved surfaces that are arranged between the pressing plates and the pressing bodies and that make point contact or line contact with the pressing plates or the pressing bodies. And a pressure seat having a portion.

Further, the curved surface portion has a hemispherical shape.

Further, the curved surface portion has a semi-cylindrical shape.

Further, the pressurizing seat has a spherical shape.

The number of pressure seats is the same as the number of tightening rods of the tightening body.

Further, the pressure seats are respectively arranged in divided regions obtained by dividing the region of the pressure plate into equal areas by the number of pressure seats.

Further, it is provided with a receiving portion having a concave surface that abuts against the pressure seat.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1. Embodiments of the present invention will be described below. 1 is an overall perspective view of a fastening device for a fuel cell according to a first embodiment of the present invention. The fastening device for a fuel cell comprises a pair of pressing bodies arranged above and below a molten salt type stack 31. An upper pressure beam 32a and a lower pressure beam 32b, tightening rods 33 penetrating both sides of the pressure beams 32a and 32b, and nuts 34 screwed to the upper and lower parts of each tightening rod 33. , The pressure spring 3 compressed between the nut 34 and the pressure beams 32a and 32b.
7, an upper pressure plate 35a and a lower pressure plate 35b respectively arranged above and below the stack 31, and these pressure plates 3
5a and 35b, respectively, and a pressure seat 38 having a hemispherical curved surface portion 38a on the upper portion. The tightening rod 50, the nut 34, and the pressure spring 37 form a tightening body 50. In addition, the pressure beam 32a,
32b, the tightening rod 33, and the pressure plates 35a and 35b are made of stainless steel or steel.

In the tightening device for a fuel cell constructed as described above, when the stack 31 is tightened by the pressure springs 37, the pressure springs 37 are arranged on both sides of the pressure beams 32a and 32b. The pressure beams 32a and 32b are flexibly deformed so that the intermediate portions thereof are separated from the pressure plates 35a and 35b, but as shown in FIG.
The load point at which the curved surface portion 38a contacts the point A slightly moves from the point A to the point B outside the pressure beam 32a. As described above, in the pressurizing seat 38 between two points separated in the direction perpendicular to the bending direction of the pressurizing beam 32a, the load point of the pressurizing seat 38 is slightly moved to the outside, and the surface of the pressurizing plate 35a with respect to the entire surface is moved. The pressure can be kept almost uniform. In addition,
FIG. 3 is an example showing the deformation of the pressure beam 32a and the surface pressure distribution when the stack 31 is tightened by the pressure spring 37 in the case of the fuel cell tightening device without the pressure seat 38.
When the pressure beam 32a is bent and deformed so that the intermediate portion of the pressure beam 32a is separated from the pressure plate 35a, the pressure beam 3
It can be seen that the load point at which 2a and the pressure plate 35a contact each other moves to the edge portion C of the pressure plate 35, and the surface pressure on the entire surface of the pressure plate 35a increases toward the outside of the pressure plate 35a.

Further, the operating temperature of the molten carbonate fuel cell is as high as about 700 ° C.
5a, 35b and the pressure beams 32a, 32b are interposed, the pressure plates 35a, 35b are connected to the pressure beam 3 by the pressure plates 35a, 35b.
The area of the heat conduction passage to 2a, 32b is small, so that it becomes difficult to transfer heat to the pressure beams 32a, 32b, and the physical strength of the pressure beams 32a, 32b does not decrease due to heat.

Further, the tightening rods 33 penetrate through both ends of the pressure beams 32a and 32b, and the pressure seats 38 are arranged corresponding to the tightening rods 33, respectively. The attached load is always the pressure seat 38.
Via the pressure plate 35a,
This contributes to uniformizing the surface pressure on the entire surface of 35b. In the above-described embodiment, the pressure seat 38 is connected to the pressure plates 35a, 3a and 3b.
Although fixed to 5b, a pressure seat may be fixed to the pressure beam. Further, one pressing seat may be brought into contact with the central portion of the pressing beam with respect to the pressing beam having the tightening rods penetrating the both ends.

Embodiment 2 FIG. Pressure seat 38 of the first embodiment
4 has a hemispherical curved surface portion 38a in the upper part, but when both end portions of the pressure beams 32a and 32b are tightened, the bending deformations of the pressure beams 32a and 32b are two-dimensionally deformed. It is also possible to use a pressure seat 39 having a semi-cylindrical curved surface portion 39a as shown in FIG.

When the pressure seat 39 is used, the surface pressure on the entire surface of the pressure plate 35a can be kept substantially uniform and the heat from the stack 31 is applied to the pressure beams 32a and 32b, as in the first embodiment. It becomes difficult to transfer heat, but the workability of assembling the fuel cell is further improved. That is, for example, when the stack 31 is tightened by rotating the nut 34, the pressure beam 32a tends to rotate in the rotation direction, but the tendency is that the pressure seat 38 and the pressure beam 32a are in point contact. Form 1 is stronger. When the position of the pressure beam 32a of, for example, 300 kg shifts during the tightening work, the pressure beam 3 is returned to its original position by using a crane.
2a must be returned. On the other hand, in this embodiment, the pressurizing seat 39 and the pressurizing beam 32a are in line contact with each other, and the frictional resistance is large.
It becomes difficult for a to rotate in the rotation direction, and it is possible to prevent the heavy pressure beam 32a from being displaced during the tightening work of the stack 31 and having to align the original position.

Embodiment 3 FIG. Also, as shown in FIG.
The pressure seat 3 is provided at the center of the divided region D in which the regions of the pressure plates 35a and 35b are divided into equal areas by the number of the pressure seats 38.
By arranging one each of the eight
The surface pressure can be made more uniform over the entire surfaces of a and 35b.

Embodiment 4 FIG. 6 is a partial side view showing another embodiment of the present invention, in which a pressure beam 32a has a receiving portion 40 abutting against a pressure seat 38 fixed thereto. The radius of curvature of the receiving portion 40 is a curved surface portion 38 a of the pressure seat 38.
It has a larger concave surface 40a. A receiving portion 40 that abuts the pressure seat 38 is also fixed to the pressure beam 32b.

By providing the receiving portion 40 which abuts the pressure seat 38, the pressure beam 32 is different from that of the first embodiment.
It is possible to reduce the change in the contact angle due to the bending deformation of a and 32b, and the movement of the load point may be small accordingly.
The surface pressure can be made more uniform with respect to the pressure plates 35a and 35b. It is also possible to prevent the displacement of the pressure beams 32a and 32b with respect to the pressure seat 38 during assembly and operation of the fuel cell.

Embodiment 5 FIG. 7 is a partial cross-sectional view showing another embodiment of the present invention, in which hemispherical groove portions 35a ₁ for mounting the spherical pressure seats 41 are formed at four locations on the upper pressure plate 35a. The lower pressure plate also has grooves for pressure seats formed at four locations. Hemispherical grooves may be formed only in the pressure beams 32a and 32b, or the pressure beams 32a and 32b and the pressure plate 35a may be formed.
You may form a groove part in each 35b. In this embodiment, the load point at which the pressure beams 32a, 32b and the pressure seat 41 abut with respect to the bending deformation of the pressure beams 32a, 32b only moves slightly outward, and the pressure plate 35 is used.
It is possible to keep the surface pressure on the entire surfaces of a and 35b substantially uniform. Further, the pressurizing seat 41 need only be placed in the groove 35a _1, and the workability of assembling the fuel cell is improved.

In each of the above embodiments, the tightening device for the molten carbonate fuel cell has been described, but it goes without saying that the present invention can be applied to a tightening device for a phosphoric acid fuel cell, for example. Further, the pressure beams 32a, 32 are used as pressing members.
Although b is used, it may be a flat plate. Further, the pressure seat may have a conical shape, or may have a shape of point contact or line contact with both the pressure beam and the pressure plate.

[0028]

Since the present invention is constructed as described above, the following effects can be obtained.

Pressure plates disposed on the upper side and the lower side of the stack, pressing bodies disposed on the upper side and the lower side of the pressure plates, and a stack of pressing bodies penetrating the corners of these pressing bodies. Since a tightening body that sandwiches the pressure plate and a pressure seat that is disposed between the pressure plate and the pressure body and is in point contact or line contact with the pressure plate or the pressure body are provided, for example, they are separated along the bending of the pressure body. By disposing the pair of pressure seats, the variation of the load point of the pressing body with respect to the pressure seats is small, and it is possible to maintain a uniform surface pressure on the stack with a simple structure and at low cost. Further, since the pressing body and the pressure plate are connected via a pressure seat having a small heat transfer area, the amount of heat transferred from the stack to the pressing body is small, and the physical strength of the pressing body is lowered due to the influence of heat. It is possible to prevent this.

Further, the curved surface portion can be formed in a hemispherical shape, the semicylindrical shape can be formed, and the pressure seat can be formed in a spherical shape by simple processing.

Further, by providing the pressure seat having the semi-cylindrical curved surface portion between the pressure plate and the pressing body, the pressing body is less likely to be displaced during the stack tightening work, and the fuel cell is assembled. Workability is improved.

Further, since the number of pressure seats is the same as the number of tightening rods of the tightening body, each of the pressure seats can contribute to uniformizing the surface pressure on the entire surface of the pressure plate.

Further, since the pressure seats are respectively arranged in the divided regions where the region of the pressure plate is divided into equal areas by the number of pressure seats, the surface pressure on the entire surface of the pressure plate can be made more uniform.

Further, since the receiving portion having the concave surface that abuts against the pressure seat is provided, the movement of the load point is small with respect to the bending deformation of the pressing body, and the uniform surface pressure with respect to the pressure plate can be further maintained. it can. Further, it is possible to prevent the displacement of the pressing body with respect to the pressure seat during assembly and operation of the fuel cell.

[Brief description of drawings]

FIG. 1 is a perspective view of a fuel cell fastening device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining flexural deformation of the pressure beam of FIG. 1 and surface pressure on the pressure plate.

FIG. 3 is an explanatory diagram for explaining the bending deformation of a conventional pressure beam and the surface pressure on a pressure plate.

FIG. 4 is a partial perspective view of a fuel cell fastening device according to another embodiment of the present invention.

FIG. 5 is a partial perspective view of a fuel cell tightening device according to another embodiment of the present invention.

FIG. 6 is a partial side view of a fuel cell tightening device according to another embodiment of the present invention.

FIG. 7 is a partial side sectional view of a fastening device for a fuel cell according to another embodiment of the present invention.

FIG. 8 is a side view showing a conventional fastening device for a fuel cell.

9 is a configuration diagram of the stack of FIG.

FIG. 10 is a perspective view of the separator plate of FIG.

[Explanation of reference numerals] 31 stack, 32a, 32b pressure beam (pressing body), 33 tightening rod, 34 nut, 35 pressure plate, 37 pressure spring, 38, 39 pressure seat, 38a curved surface portion, 39a curved surface portion, 40 receiving portion, 40a concave surface portion,
41 pressure seat, 50 tightening body (pressurizing spring, tightening rod,
nut,).

Claims (7)

[Claims] 1. A pressure plate disposed on each of the upper side and the lower side of the stack, a pressing body disposed on each of the upper side and the lower side of the pressure plate, and a pressing body penetrating a corner portion of the pressing body. A fuel including a tightening body that sandwiches the stack via a pressure seat and a pressure seat that is disposed between the pressure plate and the pressure body and has a curved surface portion that makes point contact or line contact with the pressure plate or the pressure body. Battery tightening device. 2. The fuel cell tightening device according to claim 1, wherein the curved surface portion has a hemispherical shape. 3. The tightening device for a fuel cell according to claim 1, wherein the curved surface portion has a semi-cylindrical shape. 4. The tightening device for a fuel cell according to claim 1, wherein the pressure seat has a spherical shape. 5. The tightening device for a fuel cell according to claim 1, wherein the number of pressurizing seats is the same as the number of tightening rods included in the tightening body. 6. The pressure seats are arranged in respective divided areas obtained by dividing the area of the pressure plate into equal areas by the number of the pressure seats.
The tightening device for a fuel cell according to claim 5. 7. The fuel cell tightening device according to claim 1, further comprising a receiving portion having a concave surface that abuts against the pressure seat.