JPS61126776A - Manufacturing fuel cell - Google Patents

Abstract

PURPOSE:To obtain good workability at the time of mounting, excellent heat resistance and phosphoric acid resistance and besides good air-tightness by filling unvulcanized fluororubber composed of defoamed unvulcanized fluororubber and putty-like unvulcanized fluororubber in between a gasket and the contacting face with the gasket on the side face of a cell main body, vulcanizing with heating and sealing both of them tightly. CONSTITUTION:The configuration is that fluororubber 12 which is composed of defoamed unvulcanized fluororubber and putty-like unvulcanized fluororubber attached just as putty on the face side of this defoamed unvulcanized fluororubber contacting with electrodes 2, 3, is filled in between a gasket 9 and the gasket contacting face 10 of the side face of a fuel cell main body 7 to form a filler layer and both of them are sealed. Fluororubber before vulcanization has good workability because of no elasticity and clay-like property, and besides foaming occurs at the time of vulcanization with heating owing to flow by heating and a small amount of residual solvent in the putty-like unvulcanized fluororubber 12b part and rubber enters thoroughly in the uneven surface of the gasket contacting face 10. Thereby, perfect air-tightness can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a fuel cell, and particularly to a phosphoric acid type fuel cell using phosphoric acid as a toner and a method for manufacturing the same.

[Technical background of the invention and its problems]

2. Description of the Related Art Fuel cells are conventionally known as devices that directly convert energy contained in fuel into electrical energy. This fuel cell usually has a pair of porous electrodes sandwiching an electrolyte between them, and a fluid fuel such as hydrogen is brought into contact with the back surface of one electrode, and a fluid oxidizer such as oxygen is brought into contact with the back surface of the other electrode. The system uses the electrochemical reaction that occurs at this time to extract electrical energy from between the electrodes, and as long as the fuel and oxidizer are supplied, electricity can be generated with high conversion efficiency. It is something that can extract energy.

FIG. 4 is a cross-sectional perspective view showing an example of the construction of a lip-equipped electrode type fuel cell based on the above principle and using phosphoric acid as an electrolyte. In the figure, a matrix 1 impregnated with phosphoric acid as an electrolyte is placed in the center, and above and below it are a pair of porous electrode tabs coated with a catalyst, and a positive electrode (anode) 2 made of carbon material. A unit cell is formed by sandwiching the negative electrode (cathode) 3 together. Further, on the back side of both electrodes 2 and 3 of this unit cell, there is a grooved interconnector 6 made of a mixed composite of graphite and thermosetting resin in which flow channels 4 and 5 for fluid fuel and fluid oxidizer are formed. Placed. In this case, the interconnector 60 grooves are formed on both surfaces in a manner perpendicular to each other. Then, a fuel cell main body is constructed by stacking a plurality of unit cells constituted by this unit cell and the interconnector 6.

Next, as shown in FIG. 5, the fuel cell main body 1 consisting of the unit cells and the interconnector 6 is pressed by a push plate 8 with current collector plate insulating spacers (not shown) inserted above and below. Then gas.

A fuel cell is constructed by fixing fluid supply and discharge manifolds 11 to the front, rear, left, and right sides of the fuel cell main body 7 via gates 9, respectively.

In this case, the operation is performed so that, for example, fluid fuel is supplied from the front side in the figure and residual gas is discharged to the rear side, and fluid oxidizer is supplied from the left side and residual gas is discharged to the right side.

By the way, in the conventional fuel cell configured as described above, there are various problems, particularly regarding the processing of the contact surface 10 of the gasket 9. Even if the manufacturing dimensions of the pick, the unit cell, and the interconnector 6 are precisely determined, when they are stacked during assembly, slight misalignment occurs, resulting in unevenness of about several nanometers on the side surface of the fuel cell main body 7. However, this surface is the same as the carbon material forming the unit cell and the matrix 1. impregnated with acid. Cross sections of the interconnector 6 and various materials such as sealing material (not shown) are exposed)
, and each has different physical property values, so it is difficult to mechanically scrape and smooth this surface.

Therefore, one method of smoothing this uneven surface is to apply a rubber material or a plastic material. Further, since fuel cells are normally operated at a temperature of around 200° C., materials that are heat-resistant and resistant to phosphoric acid are required for the portions that are in contact with the matrix 1 impregnated with phosphoric acid.

On the other hand, a study on fluororubber revealed that I'F-oxide vulcanized rubber has excellent phosphoric acid resistance9, and that if it is made into a knot shape with a solvent in the unvulcanized state, it is effective in smoothing the side surface of the fuel cell body. It was found that the processability was also good. However, because a small amount of remaining solvent and air contained in the unvulcanized rubber foam and flow out in a spongy manner during heat vulcanization, it was necessary to limit the areas where the putty-like rubber was used.

[Purpose of the invention]

The present invention was made in order to solve the above-mentioned problems, and its purpose is to improve processability during assembly, have excellent heat resistance, phosphoric acid resistance, and airtightness without increasing the dimensional accuracy of unit cells and interconnectors. An object of the present invention is to provide a fuel cell that is highly flexible and capable of exhibiting stable performance over a long period of time, and a method for manufacturing the same.

[Summary of the invention]

In order to achieve the above object, the present invention provides a structure in which defoamed unvulcanized fluororubber and i4 tape-shaped uncured fluororubber are used between the gasket contact surface on the side surface of the fuel cell main body and the gasket in the fuel cell described above. It is characterized in that a filled layer is formed by filling unvulcanized fluororubber, and then heated and vulcanized to bring the two into close contact.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of a cross-sectional configuration of main parts in a phosphor/acid fuel cell according to the present invention.
Parts that are the same as those in the figures are given the same reference numerals and their explanations are omitted.
Only the different parts will be described here.

1 shows a gap between the gasket contact surface 10 on the side surface of the fuel cell main body 7 in FIGS. 4 and 5 and the sket 9, and the defoamed unvulcanized 7° bare rubber and the defoamed unvulcanized rubber. A filling layer is formed by filling a fluororubber 12 made of unvulcanized fluororubber in the shape of 9 tapes, which is putty-like and applied to the surface of the vulcanized fluororubber in contact with the electrode 2.3. , the two are arranged in close contact with each other.

Further, in the above, the filling layer made of unvulcanized fluororubber 12 is formed as follows. t'), 7y Raw rubber is usually made by adding various compounding agents to raw rubber, kneading it, and then heating and vulcanizing it to give it rubber elasticity. A pre-vulcanized (unvulcanized) product to which a curing agent has been added is formed as shown in Figure 2 and attached to the side of the fuel cell main body. In other words, in Figure 2, 12a
12b is a defoamed unvulcanized fluororubber obtained by forming a sheet of unvulcanized fluororubber and defoaming the air contained during kneading at a temperature below the vulcanization temperature. The parts of the side tab unit battery that come into contact with both electrodes 2 and 3 are coated with unvulcanized fluororubber in the form of a putty made from the same unvulcanized fluorine rubber with a ketone or ester solvent. be. Then, apply this unvulcanized fluororubber 12 to the gasket contact surface 10 on the side surface of the fuel cell main body, and then apply the gasket 9 from above.
After that, they are fixed by heating and vulcanizing to give them rubber elasticity and are integrated into an airtight structure.

In the phosphoric acid fuel cell constructed by the method described above, the gasket contact surface 10 on the side surface of the fuel cell body 7 is processed using unvulcanized fluororubber to which a vulcanizing agent of NONO-OXIDE is added. Since the physical properties of the fluororubber before vulcanization are clay-like without rubber elasticity, it has good workability, and when fixed through the gasket 9, the gasket contact surface 10 on the side surface of the fuel cell main body 7 It can fill in the unevenness of the surface. Furthermore, during heating and vulcanization, foaming occurs due to fluidization due to heating and a small amount of solvent remaining in the putty-like uncured fluorine comb J, 2b, and the rubber infiltrates into every corner of the unevenness of the gasket contact surface 10, creating an airtight seal. You can have sexual perfection. In addition, by vulcanization, defoamed unvulcanized fluororubber 12 & putty-like unvulcanized fluororubber J
Needless to say, it is integrated with ob.

From the above, airtightness between the side surface of the fuel cell main body 7, the gasket 9, and the fluid supply/discharge manifold 11 can be ensured for a long period of time, thereby eliminating leakage of fluid fuel and fluid oxidizer and the resulting mixing thereof. Therefore, it is possible to obtain a fuel cell that can prevent accidents from occurring and exhibit stable cell performance over a long period of time.

As described above, according to this embodiment, a unit cell.

A peroxide vulcanizing agent is added to the interconnector 6 without increasing the laminated size of the interconnector 6 beyond the current level.
Phosphoric acid resistant unvulcanized fluororubber 12t - fuel cell main body 7
Phosphoric acid is applied to the gasket contact surface 10 on the side and is heated and vulcanized after processing to create rubber elasticity, which further improves workability during assembly and enables stable battery performance for a long time. type fuel cell is obtained.

In the above, the shape of the unvulcanized fluororubber 12 is not limited to that shown in FIG. 2, but can also be formed, for example, as shown in FIG. 3(, ) (b). The same figure (a) is formed by using two sheets of defoamed unvulcanized fluororubber 12a and inserting a solvent-containing/IP tape-like unvulcanized fluororubber 12b only in necessary parts, and the same figure (b). ) is one sheet of defoamed unvulcanized 7
It is formed by scraping off a necessary part of the string rubber 12a with a grinder, cutter, etc., and then supplementing that part with a matrix-like unvulcanized fluororubber 12b. On the other hand, as the material in this case, for example, Daiel G-902 (Daikin Industries, Ltd.: trade name) is used as a peroxide-cured seven-layer rubber, and acetone, methyl, ethyl, ketone, etc. are used as the solvent. can do.

It goes without saying that the present invention can also be applied to fuel cells using improved damaged electrodes in order to increase the amount of phosphoric acid retained in the porous electrolyte.

〔Effect of the invention〕

As explained above, according to the present invention, without increasing the dimensional accuracy of the cell interconnector, it has good workability during assembly, is excellent in heat resistance and phosphoric acid resistance, is highly airtight, and has stable performance over a long period of time. It is possible to provide a fuel cell that can achieve the desired performance and a method for manufacturing the same.

[Brief explanation of the drawing]

Figures WJ1 and 2 are a sectional view and a perspective view of essential parts showing one embodiment of the fuel cell of the present invention, Figures 3(a) and 3(b) are side views showing another embodiment of the present invention, and Figures 4 and 4 are The figure is a cross-sectional perspective view showing the structure of a conventional phosphoric acid QFPr battery, and FIG. 5 is a partial perspective view showing the assembled state of a conventional phosphoric acid TRJ battery. DESCRIPTION OF SYMBOLS 1... Matrix, box, 2, 3... Electrode, 6... Interconnector, 7... Fuel cell main body, 9... Gasket, 10... Gasket contact surface, 11... Fluid Supply and discharge manifold, 12...Unvulcanized 7° raw rubber, 12bm defoamed vulcanized fluororubber, 12b...arm-shaped unvulcanized fluororubber. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 3 t4rA Figure 5

Claims (2)

[Claims] (1) A unit cell consisting of a unit cell in which a pair of electrodes are arranged through a matrix impregnated with phosphoric acid as an electrolyte, and an interconnector arranged on the back side of each electrode and having flow grooves for fluid fuel and fluid oxidizer. In a phosphoric acid fuel cell, a manifold for supplying and discharging fluid to the pair of electrodes is disposed on the side surface of the fuel cell main body in which a plurality of the above-mentioned electrodes are laminated via a gasket. Between the gasket contact surface and the gasket, there is a defoamed unvulcanized fluororubber and a putty-like unvulcanized fluorine rubber applied to the side of the defoamed unvulcanized fluororubber that will be in contact with the electrode. A fuel cell characterized in that a packed layer is formed by filling unvulcanized fluororubber made of rubber. (2) A unit cell consisting of a unit cell in which a pair of electrodes are arranged through a matrix impregnated with phosphoric acid as an electrolyte, and an interconnector arranged on the back side of each electrode and having flow grooves for fluid fuel and fluid oxidizer. In a phosphoric acid fuel cell, in which a manifold for supplying and discharging fluid to the pair of electrodes is disposed on the side of the fuel cell main body, which is made up of a plurality of laminated layers, a manifold for supplying and discharging fluid to the pair of electrodes is arranged via a gasket. A putty-like material made of unvulcanized fluororubber made into a putty with a solvent is placed on the side of the defoamed unvulcanized fluororubber obtained by defoaming the air contained in the fluorine rubber at a temperature below the vulcanization temperature, which will be in contact with the electrode. The unvulcanized fluororubber is applied to form the unvulcanized fluororubber, and then the unvulcanized fluororubber is applied to the side of the fuel cell main body and fixed via a gasket, and then the unvulcanized fluororubber is heated and cured. A method for manufacturing a fuel cell characterized by sulfurization.