JPH10233223A - Fuel cell stack fastening device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simplified device which requires operation only at the time of a transition period of pressurizing a pressure vessel with only a pressure reducing device attached by decompressing the internal pressure of a bellows until the internal pressure of the pressure vessel reaches a prescribed pressure, and after that, releasing it to be atmospheric pressure. SOLUTION: A pressure adjusting device 7 and a compressed air source 8 are connected to a pressure vessel 5, and the internal pressure of the pressure vessel 5 is adjusted from atmospheric pressure to the operating pressure of a prescribed fuel cell. The pressure in the vessel 5 rises at a constant rate from the atmospheric pressure at the time of starting-up, and when it reaches prescribed operating pressure, the pressure is maintained. The pressure of a bellows 20 is adjusted so as to generate constant fastening force by a difference ΔPa from the pressure in the vessel 5 as negative pressure to generate constant fastening force even at the time of starting-up. After the pressure in the vessel 5 becomes ΔPa, the pressure of the bellows 20 is made into the atmospheric pressure. The decompression adjustment for the bellows 20 is required only at the time of the transition period. At the time of stationary operation, only opening to the atmosphere is required, thus, it is possible to eliminate pressure adjusting operation for reduction in maintenance cost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Molten carbonate fuel cells have features not found in conventional power generators, such as high efficiency and low environmental impact, and have attracted attention as power generation systems following hydro, thermal and nuclear power. Currently, intensive research is underway.

FIG. 9 is a schematic diagram showing a configuration of a molten carbonate fuel cell. The fuel cell has a low voltage (0.8
V), the battery is practically used as a multi-tiered battery with a separator interposed therebetween. This stacked battery is called a stack. The single cell 40 includes an electrolyte plate 4 made of a porous tile.
1 and a cathode (air electrode) 4 provided on one surface thereof
2 and an anode (fuel electrode) 43 provided on the other surface
The cathode 42 has a flow path for flowing a cathode gas, and the anode 43 has a flow path for flowing an anode gas.

FIG. 10 shows a conventional stack tightening method. The stack 1 is sandwiched between an upper plate 2 and a lower plate 3, and an airtight bellows 11 is provided on an upper surface of the upper plate 2, and a bellows holding plate 12 is mounted on an upper surface of the bellows 11. Pass the holding bolt 4 through the plate 2 and the lower plate 3,
When the bellows 11 expands, the stack 1 is tightened. The stack 1, the upper and lower plates 2 and 3, the bellows 11, and the bellows holding plate 12 are stored in the pressure vessel 5. A pressure adjusting device 7 is connected to the pressure vessel 5 by a pressurizing pipe 6.
And the compressed air source 8 are connected. A bellows pressure adjusting device 14 is connected to the bellows 11 via a bellows pressurizing tube 13, and a gas cylinder 16 is connected to the bellows pressure adjusting device 14 by a gas supply pipe 15.

[0005] During operation of the fuel cell, the pressure in the pressure vessel 5 is sequentially increased from atmospheric pressure to a predetermined pressure, for example, 5 data.
The 5ata is maintained. Bellows 1 according to this pressure
Adjust the pressure in 1 and tighten the stack 1 at a constant pressure. FIG. 11 shows changes in pressure in the pressure vessel 5 and the bellows 11. P1 indicates the pressure in the pressure vessel, and P2 indicates the pressure in the bellows 11. The bellows pressure adjusting device 14 constantly adjusts the pressure difference ΔP = P2−P1 to be constant.

[0006]

As described above, since the bellows pressure adjusting device 14 constantly adjusts the pressure, the pressure is properly adjusted due to the pressure drop of the gas cylinder 16 or the loss of the power supply to the pressure adjusting device 14. When the fuel cell stack 1 runs out, the fuel cell stack 1 may be broken due to an abnormal tightening pressure. To prevent such destruction, a gas cylinder 1
6 has been connected in parallel, measures have been taken such as periodically checking the primary pressure of the cylinder and preparing a backup power supply for the bellows pressure regulator 14. However, the primary pressure inspection work and the replacement work of the cylinders require a considerable amount of work time, and the operating costs such as the cost of the cylinders, the equipment production costs such as equipment redundancy and backup power supply become considerable and the economics of the power plant Was getting worse.

The present invention has been made in view of the above-described problems, and provides a fuel cell stack tightening apparatus that tightens a stack by using a differential pressure between the pressure in a pressure vessel and the atmospheric pressure, thereby reducing equipment costs, operation and maintenance costs. The purpose is to do.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, an upper plate and a lower plate sandwiching a stack formed by stacking fuel cells at a substantially central portion are provided between the upper and lower plates. Airtight bellows whose upper and lower ends are respectively connected to the upper and lower plates and expands and contracts in the vertical direction, and a pressure vessel that stores the stack and the bellows and the upper and lower plates sandwiching these,
The pressure vessel includes a pressure device for pressurizing the inside of the pressure vessel, and a pressure reducing device connected to the bellows for reducing the pressure inside the bellows or opening the inside of the bellows to the atmosphere.

A stack and a bellows are provided between the upper and lower plates. When the internal pressure of the bellows is made lower than the internal pressure of the pressure vessel, the upper and lower plates are attracted and the stack is tightened. When the internal pressure of the pressure vessel is low, the internal pressure of the bellows is set to a negative pressure, the differential pressure is set to a predetermined value, and a tightening force of a certain value or more is generated.
If the pressure inside the pressure vessel increases, the bellows can be set to the atmospheric pressure to secure a tightening force of a certain value or more. This reduces the internal pressure of the bellows until the internal pressure of the pressure vessel reaches the predetermined pressure,
After that, the pressure can be adjusted to atmospheric pressure without any need for pressure adjustment. Further, the bellows need not have a pressurizing device and may be a depressurizing device. Further, since the bellows only operates during the transitional period in which the pressure vessel is pressurized, the device becomes simple, and the operation and maintenance are also simplified.

According to the second aspect of the present invention, an upper plate and a lower plate sandwiching a stack formed by stacking fuel cells at a substantially central portion, and upper and lower ends provided between the upper and lower plates are respectively connected to the upper and lower plates. An airtight bellows which expands and contracts, a pressure vessel which stores the stack and the bellows and upper and lower plates sandwiching them, a pressurizing device which pressurizes the inside of the pressure vessel, and a bellows opening pipe which is connected to the bellows and opens the inside of the bellows to the atmosphere. And a spring provided between the upper plate and a spring supporting member fixed to the storage container, and pressing the stack via the upper plate.

According to the present invention, the invention of claim 1 uses a pressure reducing device to secure the tightening force in the transitional period when the pressure vessel is pressurized, while using the spring to secure the tightening force in the transitional period. It is. A stack and a bellows are provided between the upper and lower plates. As the internal pressure of the bellows becomes atmospheric pressure and the internal pressure of the pressure vessel increases, the upper and lower plates are attracted and the stack is tightened. When the internal pressure of the pressure vessel is low, a tightening force of a certain value or more is not generated, so that a fixed tightening force is applied by a spring. When the pressure inside the pressure vessel increases, a tightening force corresponding to the pressure difference from the atmospheric pressure is added. This eliminates the need for any operation of the bellows during transitional and stationary periods, simplifies the equipment, and simplifies operation and maintenance.

According to the third aspect of the present invention, an upper plate and a lower plate sandwiching a stack of fuel cells in a substantially central portion, a cylinder provided on an upper surface of the upper plate and pressing the upper plate with a rod, And a pressure vessel for storing the upper and lower plates and the cylinder sandwiching the pressure vessel, a pressurizing device for pressurizing the inside of the pressure vessel, and a decompression device connected to the cylinder tube of the cylinder to decompress the cylinder tube or open the atmosphere,
The cylinder, the upper end is open, the lower end has a rod through hole and a vertically mounted cylinder tube,
The piston includes a piston fitted to the cylinder tube, and a rod coupled to the lower surface of the piston and penetrating the rod through hole.

If the pressure in the cylinder tube is lower than the pressure in the pressure vessel, a force is generated by multiplying the pressure difference by the difference between the cross-sectional areas of the piston and the rod, and the rod end passes through the through hole and passes through the upper plate. Tighten down stack. When the internal pressure of the pressure vessel is low, the internal pressure of the cylinder tube is set to a negative pressure, the differential pressure is set to a predetermined value or more, and a tightening force of a certain value or more is generated. Power can be secured. As a result, the internal pressure of the cylinder tube is reduced until the internal pressure of the pressure vessel becomes a predetermined pressure, but thereafter, it is only necessary to release the internal pressure to atmospheric pressure, so that there is no need to adjust the pressure. In addition, the cylinder does not need a pressurizing device and need only be a depressurizing device. In addition, since the cylinder only operates during the transitional period when the pressure vessel is pressurized, the device is also simplified, and the operation and maintenance are simplified.

According to a fourth aspect of the present invention, an upper plate and a lower plate sandwiching a stack formed by stacking fuel cells at a substantially central portion, a cylinder provided on an upper surface of the upper plate and pressing the upper plate with a rod, A pressure vessel for storing the upper and lower plates and the cylinder sandwiching the pressure vessel, a pressurizing device for pressurizing the inside of the pressure vessel, a cylinder opening pipe connected to the cylinder tube of the cylinder and opening the inside of the cylinder tube to the atmosphere, and the upper plate And a spring provided between a spring support member fixed to the storage container and pressing the stack via an upper plate, wherein the cylinder is vertically mounted with an open upper end and a rod through hole at a lower end. It has a cylinder tube, a piston fitted to the cylinder tube, and a rod coupled to the lower surface of the piston and passing through the rod through hole.

According to the third aspect of the present invention, the clamping force in the transitional period when the pressure vessel is pressurized is secured by using the pressure reducing device, whereas the clamping force in the transitional period is secured by using the spring. It is. When the pressure inside the pressure vessel is increased by setting the pressure inside the cylinder tube to atmospheric pressure, a force is generated by multiplying this pressure difference by the difference in the cross-sectional area between the piston and the rod, and the rod end pushes down the upper plate through the through hole. Tighten the stack. When the pressure inside the pressure vessel is low, a tightening force of a certain value or more will not be generated.
A fixed force is applied by a spring, and when the internal pressure of the pressure vessel increases, a force due to a differential pressure is added, so that a fixed force equal to or higher than a certain value can be secured. As a result, the cylinder does not need any operation regardless of the transition period and the steady state, and the device is simplified,
Driving and maintenance are also easier.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a fuel cell stack fastening device according to a first embodiment of the present invention. In the following drawings, those having the same functions as those of the present drawing are denoted by the same reference numerals. The fuel cell stack 1 is sandwiched between an upper plate 2 and a lower plate 3 and is set on a support base 10. Pressing bolts 4 are provided through the upper and lower plates 2 and 3 so that the stack 1 and the upper and lower plates 2 and 3 do not shift left and right. An airtight bellows 20 is provided outside the stack 1 between the upper and lower plates 2 and 3, and the bellows 20 contracts vertically to apply a tightening force to the stack 1. The upper and lower plates 2 and 3 and the stack 1 and the bellows 20 sandwiched therebetween are stored in the pressure vessel 5.

A pressure regulating device 7 and a compressed air source 8 are connected to the pressure vessel 5 via a pressure pipe 6, and the internal pressure of the pressure vessel 5 is increased from atmospheric pressure to a predetermined operating pressure of the fuel cell, for example, 5 at.
Adjust to a. A heat insulating material 9 is provided on the side surface of the stack 1 to keep the fuel cell at a high temperature. A bellows opening pipe 21 is connected to the bellows 20, is led to the outside of the pressure vessel 5, and is connected to a bellows pressure reducing device 22. The bellows pressure reducing device 22 adjusts the internal pressure of the bellows 20 from negative pressure to atmospheric pressure.

FIG. 2 shows the internal pressure of the pressure vessel 5 and the bellows 20 from the start of the fuel cell to the steady operation. P1 indicates the pressure of the pressure vessel 5, and P3 indicates the pressure of the bellows 20.
P1 is increased at a fixed rate from the atmospheric pressure at the start of activation (this is referred to as pressure 0), and when a predetermined operating pressure is reached, the pressure is maintained. P3 is set to a negative pressure so that a constant tightening force is generated even at the start of startup, and is adjusted so as to generate a constant tightening force by a differential pressure ΔPa from P1. After P1 becomes ΔPa, P3 is set to the atmospheric pressure. As a result, a constant tightening force is ensured even in a transitional period, and a tightening force corresponding to the differential pressure ΔPc is generated during a steady operation.

In this embodiment, the bellows need only be depressurized and adjusted only during the transitional period, and the bellows need only be opened to the atmosphere during a steady operation, so that the pressure adjusting operation is not required. Further, since a decompression device may be provided, the device is simple and the production cost and maintenance cost may be low.

Next, a second embodiment will be described. FIG. 3 shows the second
1 shows a configuration of an embodiment. This embodiment is different from the first embodiment shown in FIG. 1 in that the bellows pressure reducing device 22 is stopped, the bellows opening pipe 21 is opened to the atmosphere, and a spring is provided between the spring support member 23 fixed to the pressure vessel 5 and the upper plate 2. 24 are provided so that a constant tightening force is always applied to the stack 1. In the figure, P1 indicates the pressure of the pressure vessel 5, and P0 indicates the atmospheric pressure.

FIG. 4 shows the tightening force applied to the stack 1 from the start of the fuel cell to the steady operation. F1 is a pressure vessel 5
And the tightening force generated when the bellows 20 expands and contracts in the vertical direction due to the differential pressure between the internal pressure of the bellows 20 and the internal pressure of the bellows 20 (atmospheric pressure). F2 indicates the clamping force applied by the spring 24. ΣF indicates the total tightening force applied to the stack 1.

In this embodiment, no operation is required to apply a tightening force of a fixed value or more to the stack 1, so that no operation cost is required for the operation, and the manufacturing cost is simple because the tightening force generating device is simple. And maintenance costs are low.

Next, a third embodiment will be described. FIG. 5 shows the third
1 shows a configuration of an embodiment. The fuel cell stack 1 has an upper plate 2
And the lower plate 3, and is set on the support base 10. Pressing bolts 4 are provided through the upper and lower plates 2 and 3 so that the stack 1 and the upper and lower plates 2 and 3 do not shift left and right. A heat insulating material 9 is provided on the side surface of the stack 1 and keeps a high temperature during operation of the fuel cell. A pressure adjusting device 7 and a compressed air source 8 are connected to the pressure vessel 5 via a pressurizing pipe 6.
The internal pressure of the pressure vessel 5 is adjusted from atmospheric pressure to a predetermined operating pressure of the fuel cell, for example, 5 data. In the figure, P1 indicates the pressure of the pressure vessel, and P3 indicates the internal pressure of the cylinder.

On the upper surface of the upper plate 2, a pneumatically operated cylinder 3 is provided.
0 is provided. The upper end of the cylinder tube 31 is open, and a through hole for the rod 33 is provided at the lower end. The piston 32 and the rod 33 are integrally formed, and the piston 32 is fitted on the inner surface of the cylinder tube 31, and the tip of the rod 33 is fitted on the rod through hole. A cylinder opening pipe 34 is connected to the cylinder tube 31, is guided to the outside of the pressure vessel 5, and is connected to a cylinder pressure reducing device 35.

FIG. 6 shows the internal pressure of the pressure vessel 5 and the cylinder 30 from the start of the fuel cell to the steady operation. P1 indicates the pressure of the pressure vessel 5, and P3 indicates the pressure of the cylinder tube 31. P1 is increased at a fixed rate from the atmospheric pressure at the start of activation (this is referred to as pressure 0), and when a predetermined operating pressure is reached, the pressure is maintained. P3 is set to a negative pressure so that a constant tightening force is generated even at the start of startup, and is adjusted so as to generate a constant tightening force by a differential pressure ΔPa from P1. P1 is ΔP
After time a, P3 is set to the atmospheric pressure. As a result, a constant tightening force is ensured even in a transitional period, and a tightening force corresponding to the differential pressure ΔPc is generated during a steady operation.

In this embodiment, the cylinder 30 is used only during the transition period.
It is only necessary to perform the pressure reduction operation described above, and it is only necessary to open to the atmosphere during the steady operation, so that the pressure adjustment operation is unnecessary. Further, since a cylinder pressure reducing device may be provided, the device is simple and the production cost and maintenance cost can be reduced.

Next, a fourth embodiment will be described. FIG. 7 shows the fourth
1 shows a configuration of an embodiment. This embodiment is different from the third embodiment shown in FIG. 5 in that the cylinder pressure reducing device 35 is stopped, the cylinder opening pipe 34 is opened to the atmosphere, and the spring support member 23 fixed to the pressure vessel 5 and the upper plate 2 A spring 24 is provided,
A constant tightening force is always applied. In the figure, P1 indicates the internal pressure of the pressure vessel 5, and P0 indicates the atmospheric pressure.

FIG. 8 shows the tightening force applied to the stack 1 from the start of the fuel cell to the steady operation. F1 is a pressure vessel 5
And the tightening force generated when the piston 32 and the rod 33 move downward due to the differential pressure between the internal pressure of the cylinder tube 31 and the internal pressure (atmospheric pressure) of the cylinder tube 31. F2 indicates the clamping force applied by the spring 24. ΣF indicates the total tightening force applied to the stack 1.

In this embodiment, no operation is required to apply a tightening force of a certain value or more to the stack 1, so that no operation cost is required by the operation, and the manufacturing cost is simple because the tightening force generating device is simple. And maintenance costs are low.

[0030]

As is apparent from the above description, the present invention uses a bellows or a cylinder to utilize the pressure difference between the internal pressure of the pressure vessel and the atmospheric pressure, thereby securing the tightening force of the stack. Since the operation for maintaining the tightening force is small and the device is simple, the production cost, the maintenance cost and the operation cost are small, and the stack tightening device is economical.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is a diagram illustrating generation of a tightening force according to the first embodiment.

FIG. 3 is a configuration diagram of a second embodiment of the present invention.

FIG. 4 is a diagram illustrating generation of a tightening force according to a second embodiment.

FIG. 5 is a configuration diagram of a third embodiment of the present invention.

FIG. 6 is a diagram illustrating generation of a tightening force according to a third embodiment.

FIG. 7 is a configuration diagram of a fourth embodiment of the present invention.

FIG. 8 is a diagram illustrating generation of a tightening force according to a fourth embodiment.

FIG. 9 is a diagram illustrating a configuration of a stack.

FIG. 10 is a configuration diagram of a conventional stack tightening device.

FIG. 11 is an explanatory diagram of generation of a tightening force of a conventional stack tightening device.

[Explanation of symbols]

 Reference Signs List 1 stack 2 upper plate 3 lower plate 4 holding bolt 5 pressure vessel 6 pressurizing pipe 7 pressure regulator 8 compressed air source 9 heat insulating material 10 support base 20 bellows 21 bellows open pipe 22 bellows pressure reducing device 23 spring support 24 spring 30 cylinder 31 Cylinder tube 32 Piston 33 Rod 34 Cylinder opening pipe 35 Cylinder pressure reducing device

Claims (4)

[Claims] An upper plate and a lower plate sandwiching a stack formed by stacking fuel cells at a substantially central portion, and upper and lower ends provided between the upper and lower plates are connected to the upper and lower plates, respectively, so that an airtight air-conditioning device that expands and contracts in a vertical direction is provided. A bellows, a pressure vessel for storing the stack and the bellows and the upper and lower plates sandwiching them, a pressurizing device for pressurizing the inside of the pressure vessel, and a depressurizing device connected to the bellows for decompressing the inside of the bellows or opening to the atmosphere, A fuel cell stack tightening device, comprising: 2. An upper plate and a lower plate sandwiching a stack of fuel cells in a substantially central portion, and upper and lower ends provided between the upper and lower plates are connected to the upper and lower plates, respectively, so that an airtight airbag which expands and contracts in a vertical direction is provided. A pressure vessel for storing the bellows, the stack and the bellows and the upper and lower plates sandwiching them, a pressurizing device for pressurizing the inside of the pressure vessel, a bellows opening pipe connected to the bellows and opening the inside of the bellows to the atmosphere, and the upper plate And a spring provided between the spring support member fixed to the storage container and pressing the stack via an upper plate. 3. An upper plate and a lower plate which sandwich a stack formed by stacking fuel cells at a substantially central portion, a cylinder which is provided on an upper surface of the upper plate and presses the upper plate with a rod, a stack and upper and lower portions which sandwich the stack A pressure vessel for storing plates and cylinders;
A pressure device for pressurizing the inside of the pressure vessel, and a decompression device connected to the cylinder tube of the cylinder to decompress the cylinder tube or open to the atmosphere, wherein the cylinder has a rod through hole at an upper end and a rod through hole at a lower end. A fuel cell stack clamp having a vertically mounted cylinder tube, a piston fitted to the cylinder tube, and a rod coupled to the lower surface of the piston and passing through the rod through hole. Attachment device. 4. An upper plate and a lower plate sandwiching a stack formed by stacking fuel cells at a substantially central portion, a cylinder provided on an upper surface of the upper plate and pressing the upper plate with a rod, a stack and upper and lower portions sandwiching the stack. A pressure vessel for storing plates and cylinders;
A pressurizing device for pressurizing the inside of the pressure vessel, a cylinder opening pipe connected to the cylinder tube of the cylinder and opening the inside of the cylinder tube to the atmosphere, and a spring support member fixed to the upper plate and the storage container are provided. A spring that presses the stack via an upper plate, wherein the cylinder is vertically mounted with a cylinder through which the upper end is opened and has a rod through hole at the lower end, and a piston that fits into the cylinder tube; A rod coupled to the lower surface of the piston and penetrating the rod through hole.