JPS60140667A - Manufacture of porous carbon plate - Google Patents

Abstract

PURPOSE:To obtain a porous carbon plate having gas impermeable layers in its ends by impregnating the end portions of each prepreg with a resin before stacking thus treated prepregs. CONSTITUTION:After a carbon fiber sheet is impregnated with a phenol resin to make a prepreg, both end portions 6 of the prepreg which are used as gas impermeable layers are impregnated with a phenol resin of such an amount as to adjust the apparent density of the end portions 6 to be 1,270 or higher. Thus treated prepregs are then stacked to form a porous carbon plate. By the means mentioned above, it is possible to form the porous portion 5 and the gas impermeable portion 6 of each prepreg simultaneously, thereby enabling a porous carbon plate to be manufactured more economically.

Description

[Detailed Description of the Invention] [Technical Field to Which the Invention Pertains] The present invention relates to a method for manufacturing a porous carbon plate, in which four portions of both side end portions are gas-impermeable layers, which are used, for example, as lipped electrode base materials for fuel cells. Regarding.

[Prior art and its problems]

A fuel cell, such as a phosphoric acid fuel cell, has a matrix layer holding an electrolyte sandwiched between a fuel electrode and an air electrode to form a single cell, and a large number of these single cells are stacked with gas separation plates in between.
A cell stack composed of assembled beans is well known. A porous carbon plate with a lip as shown in Figure 1 is generally used as the electrode base material of this battery, and the fuel gas and gas are transported from one end (part) of each electrode base material to the opposite end. At the same time, a part of it is introduced into the matrix layer through the pores 2 of the electrode base material 1, and reacts at this interface, producing so-called power generation. It is being done. Therefore, it is desirable that 100% of the fuel gas or air flowing through the electrode base material be guided to the Mad IJ gas layer.

On the other hand, the electrode base material is porous and has the drawback that fuel gas and air can freely flow in directions other than the matrix layer. This is very uneconomical from the point of view of gas utilization, and there is a great possibility that the fuel gas and air may freely come into contact and mix in locations other than the matrix layer. As is well known, contact and mixing of fuel gas and air poses the danger of combustion and, in some cases, explosion, and it is necessary to take measures to prevent the two from mixing. Taking the above into consideration, the electrode base material should be used in the flow direction 3 (ii) of fuel gas or air.
l! An electrode base material is devised in which gas-impermeable layers 1 are formed on both end portions in a direction perpendicular to the rib direction of the pole base material.

Conventional methods are used to form this gas-impermeable layer.

A method of attaching a bag-shaped film material to the end of an electrode base material serving as a gas-impermeable layer and adhering part or all of the bag-shaped film material to the electrode base material, and an electrode base serving as a gas-impermeable layer. Methods such as coating or impregnating paint or resin phenol on the outside of the phase were used.

However, the former method has a problem with the reliability of adhesion, and it is not easy to obtain complete adhesion. Moreover, it is very difficult to make the thickness of the adhesive layer uniform over the entire surface of the adhesive layer, which is one of the problems when stacking batteries. In the latter case, it is difficult to completely fill the pores in the base material with paint or resin phenol, and vacuum impregnation is usually performed several to several times. Furthermore, both methods have drawbacks such as the need to carry out the process after manufacturing the porous plate, requiring a large number of man-hours.

[Purpose of the invention]

An object of the present invention is to provide a method for manufacturing a porous carbon plate having gas-impermeable layers on both side end portions as shown in FIG. 6.

[Key points of the invention]

In the present invention, when manufacturing a porous carbon plate by stacking a number of prepregs impregnated with phenol 1/gin on a carbon fiber integrated sheet to a required thickness, and curing the resin by pressurizing and heating, By pre-impregnating the ends of the prepreg with resin and making sure that the apparent density of the resin for the four sides of both ends of the porous carbon plate after lamination molding is 1,270 or more, A porous carbon plate having a gas-impermeable layer formed by the above-mentioned gas is obtained.

[Embodiments of the invention]

Hereinafter, the present invention will be explained based on examples.

Example 1 A carbon veneer with a thickness of 0.26 M and a basis weight of 352 was impregnated with a methanol solution of 10% phenol resin. This carbon vapor is left in the air at room temperature to completely convert methanol to 3S+tWt. By repeating this resin impregnation and tutanol volatilization in the atmosphere,
Prepreg 5 was produced as shown in Figure 21E2, in which carbon paper was impregnated with resin at a light intensity of 5 and 60:*i%. Next, both side ends 6 of these prepregs 5
(Gas permeation) The portions necessary to form the pores were further impregnated with resin so that the amount of resin-impregnated pieces was 50 to 80 ML%. Stack 10 sheets of this prepreg 5, 30
A porous carbon plate of 1xlOOx 100 m was manufactured by pressurizing and heating under the conditions of 165 soil and 5''C until the resin hardened.The %ii portion of the obtained carbon plate was The apparent density and -) gas permeability are shown in Table 1.

The gas permeability measurements shown in Table 1 were carried out using nitrogen gas with a measurement area m ntrr' and a differential pressure of 1 atmosphere. Also, the apparent density of the porous part is 0.467 (6%) and 9.7
26 (60%). As you can see from the 8g1 table,
The amount of resin impregnated at the end is 75% by weight or more, and the apparent density is 1
．． It was confirmed that if it was 380 or higher, there was no dregs permeation.

Example 2 A prepreg with a resin content of 6% by weight in the porous part and a resin content of 75% by weight in the end part was manufactured using the same method and conditions as in Example 1. Take only one number of 5 to 10 pieces (1 x 101) x 1
A porous carbon plate of No. 011 III was manufactured. Table 2 shows the characteristics of the end portions.

From the results in Table 2, the apparent density is more important for gas permeation than the amount of impregnated resin, and if it is 1.26 or more, it is estimated to be good.

Example 3 Using 10 sheets of prepreg from Example 2, porous carbon plates with the same diameter and an apparent density of 1.20 to 1.30 at both end portions were used, and the thickness of the carbon plates was Produced by Aeruko and others. Table 3 shows the σ)% properties of the obtained porous carbon plate.

At an apparent density of 1.260, opacity or slight transmission is observed, and at a density of 1.270 or higher, no dregs are transmitted. As seen above, the apparent density is 1.26 in Table 2.
There are some examples of 2, but it is definitely 1. ;27 f) or more, a gas impermeable layer can be formed.

〔Effect of the invention〕

As explained above in the examples, the method for manufacturing a porous card D67 board with gas-impermeable layers on both end portions of the present invention is to apply phenol to a so-called carbon fiber integrated sheet such as carbon paper, mat or carbon cloth. Both ends of prepreg impregnated with resin, i.e. gas impermeable tV
In addition, the apparent density after laminated molding is 1.2.
Impregnated with phenol resin of 70 or more,
This is a method of lamination molding using Nofri legs, and compared to the conventional manufacturing method of porous carbon plates, in which the porous part is first produced and then the gas impermeable part is formed, the porous part and the gas impermeable part are formed. This method has the advantage that the gas-impermeable portion can be molded at the same time and is more economical.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the structure of a ribbed electrode base material, and FIG. 2 is a perspective view of a prepreg used in the present invention.

Claims (1)

[Claims] When manufacturing a porous carbon plate by stacking a plurality of prepregs in which a carbon fiber integrated sheet is impregnated with a predetermined amount of resin, and applying pressure and heat to this laminate to harden the resin, the two ends of the carbon plate after lamination molding are A method for producing a porous carbon plate, comprising impregnating an end portion of the prepreg in advance with a resin so that the apparent density of the resin in each portion is 1,270 or more.