JPH06314571A - Fuel cell - Google Patents

Abstract

PURPOSE:To increase the output density of a fuel cell without limitation in the number of unit cells to be stacked by installing the clamping mechanism of a fuel cell stack. CONSTITUTION:A fuel cell stack 1 is fixed with insulating plates 2, clamping plates 3, and plural pressure generating devices 6 each arranged in the middle of a clamping rod 5, then a pressure vessel 4 is set, and a pressed fluid is supplied to the pressure generating device 6 through a pressure transmitting pipe 9 from a pressure generating source 10 installed on the outside. The pressure generating device 6 pushes up a piston 8 inserted into a pressure generating device container 7 by the pressed fluid to compress the pressure generating device 6 and to generate clamping pressure.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a fuel cell, and more particularly,
The present invention relates to a fuel cell suitable for improving the volume (output density) of a fuel cell main body occupying a container as a power generator of a fuel cell.

[0002]

2. Description of the Related Art Conventionally, control of tightening pressure of a fuel cell stack is a factor that directly affects fuel cell performance. That is, the higher the tightening pressure, the smaller the internal contact resistance of the fuel cell. However, if the tightening pressure is too high, problems such as electrolyte stains and component deformation will occur. On the contrary, if the tightening pressure is small, fuel and oxidant gas leak. In this regard, as a means for adjusting the tightening pressure from the outside of the container, the fuel cell stack 1 is provided with a bellows 12 between the insulating plate 2 and the tightening plate 3, as shown in FIG. It is fixed by a tightening plate 3 and a tightening rod 5 at the lower part of the body 1, and a predetermined pressure is obtained by supplying a fluid pressurized by a pressure generator 10 from the outside of the pressure vessel 4 to the bellows 12 through a pressure transmission pipe 9. Pressure is generated to uniformly pressurize the fuel cell stack. In this case, a pressure adjusting mechanism 11 that detects the pressure inside the container and adjusts the tightening pressure is often provided.

[0003]

It is known that when a fuel cell is operated for a long time, the electrodes gradually contract. When 100 standard unit fuel cells are stacked and operated for about 1000 hours, a contraction of about 50 mm is expected. In order to compensate for this contraction by the bellows 12, the expandable and contractible portion of the bellows needs to have a constant height, and the height needs to be increased almost in proportion to the increase in the number of stacked layers. Therefore, in order to increase the output per fuel cell, even if the number of laminated sheets is increased, the tightening mechanism also becomes large. In this conventional example, when viewed as a source of electric power, there is a tightening mechanism above the fuel cell stack 1, so that the number of stacked cells is limited as a whole. As a result, the power density is reduced as a whole. Therefore, in order to improve the output density, a compact tightening mechanism is desirable. Further, in the case of a single bellows, when the pressure of the pressurized fluid is lost, the tightening pressure is lost all at once, so there is a danger that fuel and oxidant gas leaks immediately and a fire or explosion occurs.

The object of the present invention is not to limit the number of fuel cell stacks by the tightening mechanism of the fuel cell stacks.
An object of the present invention is to provide a fuel cell capable of improving the output density.

[0005]

According to the present invention, a fuel cell stack installed in a pressure vessel, an insulating plate is installed on the lower and upper surfaces of the stack, and two tightening plates are installed under the lower insulating plate and above. It is installed on the upper surface of the upper insulating plate, and in order to tighten the upper and lower tightening plates with the tightening rods, a tightening pressure generator is installed in the middle of the tightening rods, and the fluid pressurized from the outside to the pressure generator by the pressure transmitting means is supplied. It is configured to obtain the required tightening pressure by supplying and contracting the pressure generating device. Further, the pressure transmitting means is provided with a pressure adjusting system for adjusting the pressure of the pressurized fluid.

[0006]

With this configuration, the pressure generator is located on the side surface of the fuel cell stack, and the space in the upper part of the fuel cell stack allows more fuel cells to be stacked. It is possible to increase the battery output. When the pressure generator is a cylinder ram,
Unlike the mechanism using the bellows, it is easy to design the stroke of the sliding portion to be large, and the mechanism does not become so large even if the number of laminated layers increases. Therefore, as the output of a single fuel cell unit increases, the number of unit fuel cells that can be stacked at the same height of the fuel cell increases as compared with the conventional example, so the output density further increases. The fuel cell can be operated more safely by providing a mechanism that has a high corrosion resistance and there is no risk of pressure loss, and a backflow of the pressure fluid is prevented.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG.
The fuel cell stack 1 is fixed as shown by a plurality of pressure generators 6 installed at an intermediate position between the insulating plate 2, the tightening plate 3 and the tightening rod 5, and is covered with the pressure vessel 4, and then outside the device. The fluid pressurized from the installed pressure generation source 10 is supplied to the pressure generation device 6 through the pressure transmission pipe 9. The pressure generating device 6 pushes up the piston 8 inserted into the pressure generating device container 7 by the pressurized fluid, contracts the pressure generating device 6 and generates a tightening pressure. At this time, the pressure adjusting mechanism 11 adjusts the pressure of the pressurized fluid by the pressure inside the vessel.

In the present embodiment, the pressure generating source 10 is a hydraulic pressure source, and the pressure is transmitted by oil to the hydraulic cylinder which is the pressure generating device 6. With the configuration of this embodiment, the mechanism for tightening the fuel cell stack 1 can be installed at a position on the side surface of the fuel cell stack 1.

Further, it becomes possible to replace the conventional bellows 12 mechanism with a small cylinder ram. According to the present embodiment, by moving most of the fastening mechanism of the fuel cell to the space which was the conventional dead space, the space occupied by the bellows 12 or the like in the conventional technology can be applied to the unit fuel cell stack. Therefore, it becomes possible to stack a large number of unit fuel cells in a container having the same volume. Therefore, the output density of one fuel cell becomes large.

Further, since the cylinder mechanism of the pressure wall is used, the corrosion resistance is higher than that of the bellows 12 mechanism, and the fuel cell can be operated more safely. In the above embodiment, the same effect can be obtained by using a device using another medium such as an air cylinder as the hydraulic cylinder. Also,
The same applies to a mechanism for tightening by a mechanical mechanism. When the pressure fluctuation of the fuel cell pressure vessel is not large,
No pressure adjustment mechanism is required.

[0011]

According to the present invention, it is possible to improve the output density. In addition, a safe fuel cell can be obtained by adopting a highly reliable pressure generator.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a fuel cell according to the present invention.

FIG. 2 is a vertical sectional view showing a conventional fuel cell.

[Explanation of symbols]

1 Fuel Cell Stack, 2 Insulation Plate, 3 Tightening Plate, 4
Pressure vessel, 5 tightening rods, 6 pressure generator,
7 Pressure Generator Container, 8 Piston, 9 Pressure Transmission Pipe, 10 Pressure Source, 11 Pressure Adjustment Mechanism, 12 Bellows

Claims (3)

[Claims] 1. A fuel cell stack installed in a pressure vessel, and heat insulation and insulation on the upper surface and the lower surface of the fuel cell stack for applying a tightening pressure required for the fuel cell stack. An insulating plate, a tightening plate for transmitting a tightening pressure to the insulating plate, a tightening rod for transmitting a pressure to the tightening plate, and a pressure generating device for generating a tightening pressure between the tightening rods, A fuel cell, comprising: a pressure transmitting means for transmitting pressure to the pressure generating device. 2. The pressure transmitting means is provided with a pressure adjusting mechanism for supplying a pressurized fluid to a pressure generating device and maintaining a predetermined pressure against a pressure fluctuation in the pressure vessel. The fuel cell according to claim 1. 3. The fuel cell according to claim 1, wherein the generator is a cylinder mechanism capable of reciprocating a plurality of pressures, and generates a predetermined pressure from the pressure of the fluid transmitted from the pressure transmitting means. .