KR20150080802A - Coupling structure of ssurface pressure device for fuel cell - Google Patents

Abstract

The present invention relates to a coupling structure of an apparatus for applying surface pressure for a fuel cell, the invention comprising: a stack having a plurality of unit cells; surface pressure plates each provided at both ends along a stacking direction of the stack; and an apparatus for applying surface pressure for applying pressure such that the surface pressure plates come close to each other wherein the apparatus for applying surface pressure comprises: a surface pressure rod being coupled by passing through the surface pressure plate; a first surface pressure spring coupled to a circumference of the surface pressure rod; a second surface pressure spring having an expanded diameter compared with the first surface pressure spring and disposed outside the first surface pressure spring; and a spring support for supporting the first surface pressure spring and the second surface pressure spring to be overlapped along a stretching direction. Accordingly, it is possible to improve a surface pressure holding ability of the fuel cell and possible to reduce an overall size of a product by reducing an overall length of the surface pressure spring for the same change in length.

Description

TECHNICAL FIELD [0001] The present invention relates to a fastening structure for a fuel cell pressure-

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fastening structure of a surface pressure device for a fuel cell, and more particularly, to an improvement of a surface pressure spring structure applying surface pressure to a fuel cell. More specifically, the present invention relates to a fastening structure for a contact pressure spring capable of greatly improving the surface pressure maintaining ability (maintenance ability) of a surface pressure apparatus for a fuel cell.

Generally, a fuel cell is an apparatus for converting chemical energy stored in hydrogen or the like into electric energy by electrochemical reaction.

Bunker C Whether burning fossil fuels such as oil or heavy oil or reacting with nuclear reaction materials such as uranium or plutonium, the high-pressure steam obtained by heating the water with high temperature heat turns the turbine of the generator to generate electricity mechanically Compared with the previous generation method, the fuel cell has been actively researched and developed at home and abroad due to its high power generation efficiency and environmental friendliness.

Briefly, a fuel cell is composed of a positive electrode and a negative electrode which are insulated by an electrolyte in a container surrounded by an electric insulator, similar to ordinary batteries.

However, in order to generate a predetermined electric power, several unit fuel cells, that is, a plurality of, for example, several hundreds of unit fuel cells are maintained in series close to each other (close to each other) In this technical field, a unit structure of a fuel cell in which a plurality of unit cells are stacked in such a manner that they are uniformly closely stacked is called a "stack ".

Since heat is generated in the stack during the operation of the fuel cell, a physical change such as thermal expansion or contraction occurs in the stack, so that the standard of the stack tends to vary, That is, the nonuniformity of the intimate strength appears.

It is necessary to keep the proper close strength and uniform contact between the cells to reduce the resistance due to the contact and to prevent the decrease in efficiency so that the intimate strength should be maintained within the range that the unit cell electrode can withstand.

In addition, the problem of preventing the leakage of gas generated from the inside during use of the fuel cell is also increasing.

If the intimate strength between the cells is not properly maintained or non-uniformity occurs, inter-cell contact is not made and a gap may be generated, which may lead to gas leakage.

If these problems are not solved, the fuel cell will eventually fail or the power generation efficiency will be greatly deteriorated.

An example of a typical constitution principle of a stacked assembly in a molten carbonate fuel cell (MCFC) will be briefly described with reference to FIG.

1, the fuel cell 100 is assembled with a top surface pressure plate 103 and a bottom surface pressure plate 104 with a stack 102 composed of a plurality of unit cells 101 therebetween, The surface pressure plate 104 is slidable along the surface pushing rod 105 toward the upper surface pressure plate 103.

A surface pressure springs (106) are attached to a surface pushing rod (105) extending below the lower surface pressure plate (104). Here, reference numeral 107 denotes a surface pressure spring support plate disposed between the lower surface pressure plate 104 and the surface pressure springs 106, and 108 denotes a spring adjustment plate. Each of the contact pressure springs (106) is fixed to the contact pressure spring support plate (107) by a bolt (109).

The pressure applied between the upper surface pressure plate 103 and the lower surface pressure plate 104, that is, the surface pressure is adjusted by appropriately tightening the bolts 109 in the directions as indicated by arrows in FIG. 1, (101) can be brought close to each other at a constant pressure.

Fig. 2 shows details of the coupling of the contact pressure springs 106 shown in Fig. 1, and the reference numerals are the same as those shown in Fig. 1. Fig. 3 shows the arrangement principle of the contact pressure springs 206 Grams.

The fuel cell 100 is assembled during the initial length L ₀ of compressing a contact pressure spring 106 to L ₁ of the compressive force of the spring as a reduced length ΔL (= L ₀ -L ₁₎ (F = k х of ΔL, k is Spring constant) between the upper surface pressure plate 103 and the lower surface pressure plate 104.

However, when the fuel cell 100 is operated, the length SL of the stack is reduced due to a change in the physical properties of the stack. Accordingly, the compressed length L ₁ of the pressure-applying springs 106 is increased so that the compressive force, .

In order to prevent the decrease of the surface pressure, the change of the length change DELTA L of each of the surface-bearing springs 106 with respect to the initial surface pressure must be increased to relatively decrease the ratio of the length variation to the initial surface pressure. The attenuation will be reduced.

That is, since the change in the length of the stack during operation of the fuel cell is the same, the increase in the length L ₁ of the compressed pressure-bearing springs 106 is correspondingly equivalent.

Thus, if a compressing ΔL of the contact pressure spring 200mm to provide the same pressure F ₀ during assembly and 400mm Had the length of the stack 100mm reduced both in case of compression, when a 200mm compression is the ΔL of 100mm initial compressive force F ₀ Contrast Compression force is reduced by 50%, and when 400 mm is compressed, ΔL is reduced to 300 mm, compressive force is reduced by 25% compared to initial compressive force F ₀ .

Therefore, if the change amount DELTA L of the compression length of the initial pressure-applying spring is increased, the amount of reduction of the surface pressure due to the reduction of the stack length can be relatively reduced.

However, in order to largely change the initial length, the initial length L ₀ of the contact pressure springs becomes longer, and the length of the entire lower end of the stack increases. This results in a problem such as occupation of unnecessary space.

However, because the surface pushing rod 105 must be installed through the hole of the lower surface pressure plate 104, a fine gap is generated between the surface pressure plate and the surface pushing rod, and a gas There is a risk of leaking to the outside.

When the gas inside the fuel cell leaks to the outside, the efficiency is decreased because of the loss of utilization of the whole gas. As the hot gas of 650 ° C flows out to the outside, the thermal damage of the pressure- Can occur.

Considering this point, a number of improvement methods and apparatuses relating to a pressure-bearing device for a fuel cell have been proposed. The following is a list of the most recent domestic and foreign patent literature on this subject.

(a) U.S. Patent No. 6,797,425 B2

(b) Korean Patent Laid-Open No. 10-2010-0136723 A

(c) Korean Unexamined Patent Publication No. 10-2011-0017294 A

In the patent document (a), a fuel cell stack pressurizing device having a structure similar to that of the example of FIG. 1 described above is described. A gas leakage preventing wall for preventing gas leakage is provided outside the fuel cell container, And the connecting means is separately provided, so that the push rod can move in a flexible manner. In particular, this patent discloses that by providing a pressure-applying spring assembly composed of a plurality of coil-shaped springs in a concentric circular form around the surface pressing bar of the surface pressure plate, the spring can have various lengths in the uncompressed state, A structure for keeping the compression force on the stack constant is proposed.

In Patent Document (b), the displacement of the surface pressure plate is uniformly set between the stack surface pressure plate and the reference plate so that the pressure applied to the stack surface pressure plate of the fuel cell can be maintained between the minimum stress and the allowable stress And a displacement sensor for automatically interlocking with the surface pressure action of the surface pressure spring between the stacked surface pressure plate and the reference plate is provided so that the stack surface pressure device of the fuel cell is automatically As well as a method and an apparatus for controlling the same.

In addition, in the patent document (c) of the present applicant, a guide member for guiding the lower surface pressure plate in a slidable manner from the outside of the lower surface pressure plate (second plate) of the fuel cell is provided with a pressure member and a rotating force And a worm which meshes with the worm wheel and the worm wheel to transmit the rotational force to the surface pressure plate.

However, although each of the above patent documents discloses a surface pressure control device for a fuel cell stack, the improvement of the surface pressure device, i.e., the surface pressure spring structure, which the present invention seeks to pursue is not described. In addition, the contact pressure springs in these patent documents also do not solve the drawbacks that the overall length of the spring can not be reduced with respect to the conventional drawbacks described in relation to Fig. 1, .

Accordingly, it is an object of the present invention to provide a sealing structure of a surface pressure device for a fuel cell capable of improving the surface pressure holding ability of the fuel cell.

Another object of the present invention is to provide a fastening structure for a surface pressure device for a fuel cell, which can reduce the overall size of a product by reducing the overall length of the surface-bearing springs with respect to the same length variation.

It is still another object of the present invention to provide a fastening structure of a surface pressure device for a fuel cell capable of suppressing leakage of gas generated in the fuel cell.

In order to achieve the above object, the present invention provides a battery pack comprising: a stack having a plurality of unit cells; A surface pressure plate provided at both ends along the stacking direction of the stack; And a surface pressure device for pressing the surface pressure plate so as to approach each other, wherein the surface pressure device comprises: a surface pushing rod coupled through the surface pressure plate; A first surface pressure spring coupled to the periphery of the surface pushing rod; A second surface pressure spring having an expanded diameter as compared with the first surface pressure springs, the second surface pressure spring being disposed outside the first surface pressure springs; And a spring support portion for supporting the first surface-pressing spring and the second surface-pressing spring so as to overlap each other along the stretching direction.

Here, the spring support may include: a first surface pressure spring support portion for receiving and supporting one end of the first surface pressure spring; And a second surface pressure spring supporting portion extending in a radial direction at an end of the first surface pressure supporting spring and supporting one end of the second surface pressure applying spring.

The first surface pressure spring support portion may include a through hole into which the surface pushing rod is inserted.

The surface pressure device may further comprise a spring support plate spaced from the surface plate and supporting the end of the first surface pressure spring or the second surface pressure spring.

The surface pressure device may further comprise a flexible corrugated tube having one end connected to the bottom plate and the other end connected to the spring support plate to seal the periphery of the surface pushing rod.

The surface pressure device further includes a third surface pressure spring having a diameter different from that of the first surface pressure spring and the second surface pressure spring and disposed on the side of the first surface pressure spring or the second surface pressure spring And the like.

The third surface pressure springs may have a larger diameter than the second surface pressure springs and may be provided on the first surface pressure spring side.

The spring support includes a second surface pressure spring support portion for receiving and supporting one end of the second surface pressure spring; And a third surface urging spring support portion extending radially from an end of the second surface urging spring support portion and supporting one end of the third surface urging spring support portion.

As described above, according to the embodiment of the present invention, since the first surface pressure spring and the second surface pressure spring having different diameters and partially overlapping each other along the expansion and contraction direction are provided, The surface pressure maintaining ability of the battery can be improved.

In addition, the total length of the contact pressure springs is reduced with respect to the same length change, so that the total length of the fuel cell can be reduced.

Further, by sealing the joint region of the surface abutment bar and the surface plate with a flexible bellows, leakage of gas generated in the fuel cell can be suppressed.

1 is a schematic view showing a typical configuration example of a conventional fuel cell (for example, a molten carbonate fuel cell)
Fig. 2 is an exemplary view showing an installation state of the contact pressure spring of Fig. 1,
FIG. 3 is a diagram showing an arrangement state and an action of the contact pressure spring of FIG. 2,
4 is a view showing a fastening structure of a surface pressure device for a fuel cell according to an embodiment of the present invention,
FIG. 5 is a diagram showing the arrangement and operation of the contact pressure springs of FIG. 4,
Fig. 6 is an enlarged view of the spring-supporting member of Fig. 4,
7 is a view showing a fastening structure of a surface pressure device for a fuel cell according to another embodiment of the present invention,
Figure 8 is a diagram showing the principle and action of the arrangement of the contact pressure springs of Figure 7,
Fig. 9 is an enlarged view of the spring supporting member of Fig. 7,
10 is an exemplary view showing a state in which a flexible bellows pipe is installed in a contact pressure spring device of a fuel cell according to the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The same reference numerals will be used for the sake of convenience in the description of the present invention.

As shown in FIG. 4, a surface pressure device for a fuel cell according to an embodiment of the present invention includes: a stack 102 having a plurality of unit cells 101; A surface pressure plate (103, 304) provided at both ends along the stacking direction of the stack (102); And a surface pressure device for pressing the surface pressure plates (103, 304) so as to approach each other, the surface pressure device comprising: a surface pushing bar (305) penetrating through the surface pressure plates (103, 304); A first surface pressure spring (306a) coupled to the circumference of the surface pushing rod (305); A second contact pressure spring 306b having an expanded diameter as compared with the first contact pressure spring 306a and disposed at the outer periphery of the first contact pressure spring 306a; And a spring retainer 307 for supporting the first and second surface pressure springs 306a and 306b so as to be overlapped with each other along the expansion and contraction direction.

The plurality of unit cells 101 may be stacked so that they face each other along the up and down direction in the drawing.

The stack 102 may include a plurality of unit cells 101 stacked on each other.

Surface pressure plates 103 and 304 may be provided at both ends of the stack 102, respectively.

The surface pressure plates 103 and 304 may include an upper surface pressure plate 103 and a lower surface pressure plate 304, for example.

The surface pressure plate (103, 304) may be coupled with a surface pushing rod (305).

The surface pushing rods 305 may be composed of a plurality of surfaces.

The surface abutment rod 305 may be embodied as a bolt having, for example, a head and a male screw portion 309. [

The surface abutment rod 305 can be coupled such that the head is disposed on the upper surface pressure plate 103 side and the male screw portion 309 is disposed on the lower surface pressure plate 304 side.

Each of the surface pushing rods 305 may be disposed on the outer side of the stack 102.

The surface pressure device may be provided on the lower surface pressure plate 304, for example.

The first surface-urging spring 306a and the second surface-urging spring 306b may be embodied by, for example, an air-core coil spring.

The first and second surface pressure springs 306a and 306b may be formed of, for example, a coil spring having a circular cross section.

A surface pushing rod 305 may be inserted into the lower surface pressing plate 304 through the center thereof.

For example, a U-shaped cylindrical spring spring 307 and a spring support plate 308 may be disposed around the surface pushing bar 305.

A first surface pressure spring 306a is provided between the spring support member 307 and the spring support plate 308. [

The first contact pressure spring 306a may be shorter than the conventional contact pressure spring 106 shown in Fig. 2, for example.

One end of the first contact pressure spring 306a may be inserted and installed in the spring intermediate support 307.

A spring support plate 308 may be provided at the lower end of the outer pressure-receiving spring 306b.

A through hole may be formed in the spring support plate 308 to allow the surface pushing rod 305 to be inserted.

A nut 310 screwed to the male screw portion 309 of the surface pushing rod 305 may be provided on the lower side of the spring support plate 308. [

The length of the second contact pressure spring 306b may be the same as that of the first contact pressure spring 306a.

The second surface pressure springs 306b may be 0.5 to 1.5 times the length of the first surface pressure springs 306a.

The diameter of the second contact pressure spring 306b may be larger than the diameter of the first contact pressure spring 306a.

For example, the diameter of the second contact pressure spring 306b may be 1.5 to 2.5 times the diameter of the first contact pressure spring 306a.

As shown in FIG. 6, for example, the spring support member 307 includes a first surface pressure spring support portion 307a for receiving and supporting one end of the first surface pressure applying spring 306a therein; And a second surface pressure spring supporting portion 307b extending in the radial direction at an end of the first surface supporting spring support portion 307a and supporting one end of the second surface pressure supporting spring 306b.

The first surface pressure spring support portion 307a may have, for example, a cylindrical shape whose one side is opened.

The first surface pressure spring supporting portion 307a may have a cut end portion 307c.

The end of the first surface pressure spring 306a can be contacted and supported on the inner surface of the cut end 307c

The cut end 307c may be provided with a through hole 307d so that the surface pushing rod 305 can be inserted, for example.

According to this configuration, when the nut 310 is rotated to press the spring support plate 308, the second surface pressure spring 306b is compressed and presses the spring retainer 307. At the same time, the first surface pressure spring 306a can be compressed. This compressive force applies a predetermined surface pressure to the lower surface pressure plate 304 so that an appropriate surface pressure can be provided to the stack 102 between the upper surface pressure plate 103 and the lower surface pressure plate 304.

As described above, when the first and second surface-bearing springs 306a and 306b are installed, as shown in FIG. 5, when using springs having the same compression ratio with respect to the same load, with the length (s) short initial length (L2) and by the relative overlapping as compared to L ₁ may have a smaller compression length.

Or the spring length of the conventional spring structure is equal to the compressed length, the spring constant of the double spring structure is lowered so that the initial length becomes longer and the length change? L relatively increases. Thus, The compressive load can be maintained.

The relationship between the load according to the spring length and the change in the length of the spring is shown in the following Table 1

Load and length change


division Condition Initial value
stack
Change in length
(mm) After changing the length Individual spring length (mm) Individual spring constant
(kg / mm) Initial Length (mm) Overlap length (mm) Early
Load (kg) compression
Spring Length (mm) Spring compression ratio compared to initial (%) Load (kg) Spring Length (mm) Load holding ratio (%) Length comparison
(%) existing 400 35 400 (L ₀ ) - 5000 257
(L ₁ ) 64 -50 3250 307 65 100 Example 1 200 70 300 100
(S) 5000 157
(L ₂ ) 64 -50 3250 207 65 67 Example 2 270 52 400 130
(S) 5000 207
(L ₂ ) 64 -50 3704 257 74  84 Example 3 330 43 490 170
(S) 5000 257
(L ₂ ) 65 -50 3925 307 79 100

The lengths of the individual springs are the lengths of the respective springs used in the fastening structure, and the spring constants corresponding to the lengths of the individual springs are indicated in the side columns .

It is assumed that the two spring constants used in Examples 1 to 3 are the same. The initial total length represents the distance between the ends of the spring coupling when the spring is engaged. In the case of the conventional spring structure, one spring is used, which is the same value. The overlap length corresponds to the length S shown in the figure as a length that overlaps each other in the double spring structure.

 The initial values at the top are the respective dimensions when the initial pressure value is combined in the pressure-tightening structure, and the load is a value provided between the bottom surface pressure plate 304 and the pressure-spring spring support plate 308.

Generally, four stacked clamping structures are installed and operated. Therefore, the load applied to the stack corresponds to the number of clamping structures. When four clamping structures are provided, a load of four times is provided to the stack.

The compression spring length is given by the initial load value as described above, and it shows the compressed length, which shows how much the overall length of the fastening structure of the conventional pressure reducing device is reduced. In Table 1, the spring compression ratio represents the compressed length ratio to the length before the initial load application.

In Table 1, the stack length change shows an example in which the length of the stacked cells is reduced according to the operation of the fuel cell. As a result, the total length of the spring is increased by the reduced length of the stack, and the length of the spring after the length change is increased, thereby reducing the load value provided by the spring.

The load retention rate is a value obtained by calculating the ratio of the later load value decreased with respect to the initial load value, and is a value showing how much the conventional load is maintained. The length comparison in Table 1 is a value indicating a length change amount of each example as a ratio when the length change of the existing spring is taken as 100. [

In Table 1, in the conventional case, the installation length of the entire compressed spring is 257 mm, and the load is reduced from 5,000 kg to 3,250 kg according to the change of the stack length, and the load is maintained at 65%.

In the case of Example 1, it is a case in which the lengths of the springs are made the same and the load holding ratio is made the same. In this case, the spring whole length of the connecting structure, while maintaining the same load retention rate, as shown in the table to see that the decrease in the existing spring 257mm (L ₁₎ compared to 157mm (L ₂₎ and which is both reduced the overall length by 39% compared to existing . Also, after the length of the stack is reduced after operation, the total length of the spring compared to the conventional one is as short as 67%.

In the case of Example 3, when the entire length of the compressed spring is taken to be the same, the effect of the double spring coupling structure is shown, and the spring length compressed to the initial load is the same (L ₁ = L ₂ ) The change of the back load is maintained at 3,925 kg as compared with the existing 3,250 kg, which indicates that the surface pressure is well provided by 14% of the initial load value.

The case of Example 2 corresponds to the intermediate value between Example 1 and Example 3, which is an example of a case in which the total spring length is reduced to some extent and the load holding capability is partially increased.

Hereinafter, a fastening structure of a surface pressure device for a fuel cell according to another embodiment of the present invention will be described with reference to FIGS. 7 to 9. FIG.

As shown in FIG. 7, a surface pressure device for a fuel cell according to another embodiment of the present invention includes a stack 102 having a plurality of unit cells 101; A surface pressure plate (103, 304) provided at both ends along the stacking direction of the stack (102); And a surface pressure device for pressing the surface pressure plates (103, 304) so as to approach each other, the surface pressure device comprising: a surface pushing bar (305) penetrating through the surface pressure plates (103, 304); A first surface pressure spring (306a) coupled to the circumference of the surface pushing rod (305); A second contact pressure spring 306b having an expanded diameter as compared with the first contact pressure spring 306a and disposed at the outer periphery of the first contact pressure spring 306a; A third contact pressure spring 306c having a different diameter from the first contact pressure spring 306a and the second contact pressure spring 306b and disposed on the first contact pressure spring 306a or the second contact pressure spring 306b side, And a spring support 307 for supporting the first and second surface pressure-receiving springs 306a to 306c so as to be overlapped with each other in the elongating and contracting direction.

The first surface pressure spring 306a, the second surface pressure spring 306b, and the third surface pressure spring 306c may be realized by, for example, a cylindrical coil spring.

The third contact pressure spring 306c may be configured to have a larger diameter than the diameter of the second contact pressure spring 306b.

The third contact pressure spring 306c may be disposed on the first contact pressure spring 306a.

Meanwhile, a spring retainer 307 may be provided between the first surface pressure spring 306a and the second surface pressure spring 306b.

9, the spring retainer 307 includes a first surface pressure spring support portion 307a for receiving and supporting one end of the first surface pressure spring 306a, A second surface pressure spring support portion 307b formed in a cylindrical shape extending in the radial direction at the end of the support portion 307a to receive and support one end of the second surface pressure spring 306b, And a third surface pressure spring supporting portion 307e that extends in the direction of the second surface pressing spring 306c and supports the third surface pressure applying spring 306c.

The first surface pressure spring supporting portion 307a may have a cut end portion 307c.

The cut end 307c may be provided with a through hole 307d through which the surface pushing rod 305 can be inserted.

The length of the third contact pressure spring 306c may be the same as the length of the first contact pressure spring 306a.

The length of the third contact pressure spring 306c may be 0.5 to 1.5 times the length of the first contact pressure spring 306a.

The diameter of the third contact pressure spring 306c may be, for example, 1.5 to 3 times the diameter of the first contact pressure spring 306a.

By adopting the triple spring structure as described above, the support pressure points of the respective springs can be more stably maintained.

In addition, the first and second surface pressure springs 306a and 306c may have a spring constant of, for example, half that of the second surface pressure springs 306b. As a result, the same compression characteristics as those of the second surface pressure springs 306b can be exhibited by the spring characteristics obtained by adding the two first surface pressure springs 306a and the third surface pressure springs 306c in parallel.

7, similarly to the first embodiment, the initial length L3 and the compression length can be reduced, or the capacity of maintaining the compression load according to the change in length during operation of the stack can be increased.

Here, the effect of this embodiment is the same as that of the above-described embodiment, but it is preferable because a spring having a low spring constant can be used because of its structural stability.

10 schematically shows a coupling relationship between the lower surface pressure plate 504 and the surface pressure rod 505 of the fuel cell.

A through hole 504a may be formed in the lower surface pressure plate 504 so that the surface pushing rod 505 can pass through.

A surface pressure guide ring may be provided inside the through hole 504a of the lower surface pressure plate 504 so as to guide the surface pushing rod 505. [

The surface pushing rod guide rings may be composed of a plurality of.

The face contact guide ring may include, for example, an upper face stick guide ring 510a and a lower face stick guide ring 510b which are vertically spaced apart from each other.

The face contact guide ring 510a and the lower face slide contact guide ring 510b are formed to have an insertion portion to be inserted into the through hole 504a and a through hole 504a formed to be larger than the through hole 504a, And a blocking portion for blocking the hole 504a.

The face pushing rod guide ring 510a and the lower face pushing stick guide ring 510b may be respectively formed with inserting holes formed to allow relative sliding motion by inserting the face pushing rod 505. [

The face pushing guide ring 510a and the lower face pushing stick guide ring 510b may be fastened by the fastening member 511 so as to be prevented from being separated from the through hole 504a.

Meanwhile, gas generated inside the fuel cell stack during operation of the fuel cell can be discharged to the outside through the gap G between the lower surface pressure plate 504 and the surface pushing rod 505. [

In the present invention, as shown in the figure, a flexible corrugated tube or a flexible corrugated tube FS (hereinafter referred to as a flexible corrugated tube FS )) May be provided.

The flexible bellows pipe FS can be fixed to the lower surface pressure plate 504 at one end thereof (upper end in the drawing) by the fixing means 513 including the gasket 514.

The fixing means 513 includes a gasket supporting portion 516 for supporting the gasket 514 and a fixing portion 516 for fixing the gasket 514 and the gasket supporting portion 516 to the lower surface pressure plate 504 And may be provided with a fixing member 517 for fixing.

The fixing member 517 may be screwed to the lower surface pressure plate 504 by a fixing bolt 518.

The other end (lower end in the drawing) of the flexible bellows pipe FS may be coupled to the spring support plate 508 of the surface pushing rod 505. Although not specifically shown in the drawings, the gap between the spring support plate 508 and the surface pushing rod 505 may be configured to be sealed by a sealing means (e.g., a gasket or the like).

A nut 509 screwed to the male screw portion 519 of the flat push rod 505 may be provided on the lower side of the spring support plate 508.

The flexible bellows pipe FS is disposed inside the surface pressure springs 506 (including the pressure-bearing springs 307a, 307b, and 307c of the configurations shown in Figs. 4 to 9) .

According to this configuration, even if the gas generated inside the stack is discharged through the gap G, the gas is prevented from flowing out to the outside because of being sealed by the flexible bellows pipe FS, It is possible to flexibly operate with respect to the motion of the robot.

The surface pushing rod guide rings 510a and 510b can hold the surface pushing rod 505 and support the pushing rod 505 so as not to swing from side to side. Thus, the surface pushing rod 505 can slide in a fixed position with respect to the transverse direction. In other words, since the inner surface of the surface guide rings 510a and 510b is smooth, sliding movement of the surface pressing rod in the longitudinal direction can be performed smoothly even in a state of being in contact with the surface pressing rod 505.

The foregoing has been shown and described with respect to specific embodiments of the invention. However, the present invention may be embodied in various forms without departing from the spirit or essential characteristics thereof, so that the above-described embodiments should not be limited by the details of the detailed description.

Further, even when the embodiments not listed in the detailed description have been described, it should be interpreted broadly within the scope of the technical idea defined in the appended claims. It is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

101: unit cell 102: stack
103: upper surface pressure plate 304: lower surface pressure plate
305: face push rod 306a: first face pressure spring
306b: second surface pressure spring 306c: third surface pressure spring
307: spring support portion 307a: first surface pressure spring support portion
307b: second surface pressure spring support portion 307c:
307d: through hole 307e: third surface pressure spring supporting portion
308: spring support plate 309: male thread portion
310: nut

Claims (8)

A stack having a plurality of unit cells;
A surface pressure plate provided at both ends along the stacking direction of the stack; And
And a surface pressure device for pressing the surface pressure plates toward each other,
The surface-
A surface abutting rod which is inserted through the surface pressing plate;
A first surface pressure spring coupled to the periphery of the surface pushing rod;
A second surface pressure spring having an expanded diameter as compared with the first surface pressure springs, the second surface pressure spring being disposed outside the first surface pressure springs; And
And a spring support member for supporting the first surface-urging spring and the second surface-urging spring in an overlapping manner along the elongating and contracting direction. [2] The apparatus according to claim 1,
A first surface urging spring supporting portion for receiving and supporting one end of the first surface urging spring; And
And a second surface urging spring support portion extending in a radial direction at an end of the first surface urging spring support portion to support one end of the second surface urging spring. 3. The method of claim 2,
And the first surface-urging spring support portion is provided with a through-hole through which the surface-pressing rod is inserted. The method according to claim 1,
Wherein the surface pressure device further comprises a spring support plate spaced from the surface pressure plate and supporting an end of the first surface pressure spring or the second surface pressure spring. 5. The method of claim 4,
Further comprising: a flexible bellows pipe connected to the bottom plate at one end and connected to the spring support plate at the other end to seal the periphery of the bellows pushing rod. 6. The method according to any one of claims 1 to 5,
The surface pressure device further includes a third surface pressure spring having a diameter different from that of the first surface pressure spring and the second surface pressure spring and disposed on the side of the first surface pressure spring or the second surface pressure spring And the fastening structure of the surface pressure device for a fuel cell. The method according to claim 6,
Wherein the third surface-urging spring has a larger diameter than that of the second surface-urging spring and is provided on the side of the first surface-urging spring. 8. The method of claim 7,
The spring support includes a second surface pressure spring support portion for receiving and supporting one end of the second surface pressure spring; And
And a third contact pressure spring support portion formed to extend radially from an end of the second contact pressure spring support portion and to support one end of the third contact pressure spring support portion.

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