JPS6041764A - Fuel cell electrode manufacturing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the method of manufacturing a ribbed electrode for a fuel cell having an electrolyte reservoir.

[Prior art and its problems]

Figure 1 shows conventional electrolyte fixed fuel? lff, shows a cross-sectional view of the structure of the pond. In FIG. 1, a porous electrode base material 1 has ribs 2 on one surface, and a catalyst layer 3 is in contact with the other surface where ribs 2 are not provided, and this catalyst layer 3 has a predetermined amount of The matrix holding the electrolyte is in contact with the matrix 4. Further, an airtight separator plate 6 is disposed on the upper surface of the rib 2 of the porous electrode base material 1 so as to be in contact with the rib 2 and to form a gas compartment 5 .

In a fixed electrolyte fuel cell having such a configuration, thermal expansion of the electrolyte occurs due to operating conditions.

To suppress changes in the volume of the electrolytic solution due to shrinkage and absorption of moisture from the outside, and to compensate for the decrease in the amount of electrolytic solution in the matrices and containers due to evaporation or scattering of the electrolytic solution due to reaction gases, etc. IJ, dissolve solution 1. It is necessary to provide a t-adjustment function. Therefore, the fuel cell having the configuration shown in FIG. 1 has the function of regulating this ηi; 71 (
Preventing leakage of nT liquid / 1st, polytetrafluoroethylene (1) TFE) dispersion sweet and tetrafluoroethylene fluoroalkylvinyl 71j: Synthetic resin (
PFA) was applied and heat treated to remove water. On the other hand, the catalyst layer 3 has an electrolytic solution reservoir 7 and a communication section 8 so that the 1L solution can be easily transferred between the electrolyte reservoir 7 and the matrix 4.
is provided.

Conventionally, two methods have been used to provide this communication portion 8. In the first method, when applying the catalyst layer 3 to the porous electrode base material 1, the catalyst layer 3 is placed in advance at a position that matches the electrolyte reservoir 7 and has an outer diameter of 1, and the contact ρV and the debris 3 are removed. A member with a thickness equal to or slightly larger than the coating thickness is placed, and after coating the catalyst layer 3, this side is removed,
An L-groove is formed on the trace to form the communication part 8.
There is a pattern printing method in which the hydrophilic matrix 4 is printed with the same material as Hamura II + (. When the surface of the catalyst layer 3 is connected to the layer liquid reservoir 7, a hole or groove having a desired shape is formed by machining to form a communication part 8, and the catalyst layer 3 has hydrophilic properties. This is the same method of filling Hamura as in Matrix 4.

However, in any of these methods, in order to sufficiently perform the reservoir function of adjusting the M solution m to 1, in order to communicate the electrolyte rear buff with the matrix 4, it is necessary to match the electrolyte reservoir 7. Scabbard ttC
Catalyst layers are often painted separately, but holes or grooves must be machined and then filled with hydrophilic feathers, which not only complicates the electrode manufacturing process but also increases the number of man-hours. There were drawbacks.

[Purpose of the invention]

The object of the present invention is to eliminate the above-mentioned drawbacks, and to provide a simple method for producing an IW liquid solution sorber matrix, an aqueous liquid solubilizer, and an aqueous solution having an electrolyte adjustment function. It is about providing.

[Key points of the invention]

The present invention provides a porous electrode substrate with water-repellent properties corresponding to the electrolyte reservoir.
This is because F B can be heated and this part is made hydrophilic.

[Embodiments of the invention]

The present invention will be explained below based on examples. Since the configuration of the fuel cell to which the method of the present invention is applied is the same as that shown in FIG. 1, FIG. 1 will also be used in the description here. The present invention differs from the conventional method in that the communication portion 8 between the electrolyte reservoir 7 provided in the catalyst layer 3 and the matrix 4 is aligned with the electrolyte reservoir 7 instead of forming holes and grooves in the catalyst layer 3. Vibration by ultrasonic waves Vc is applied spot-wise to the position of the catalyst layer 3 to remove the water-repellent bonds I present in the catalyst layer 3.
By thermally decomposing PTFE at about 400°C,
That part is made hydrophilic, giving it permeability to the electrolyte. By appropriately selecting the shape of the electrode that transmits the vibrations of the ultrasonic oscillator, a hydrophilic part, that is, a communicating part 8, which has good permeability to electricity 11N, can be formed in the shape of a dot, for example, about 1 dragon in diameter, when viewed from the stacking direction of the catalyst layer 3. It can be made into a wire that passes through the catalyst, or it can be made into a linear shape with a diameter of about 11 mm, and because it is processed by ultrasonic processing, the dimensions are highly accurate.

Further, the method of the present invention may be any method as long as it can generate thermal energy to thermally decompose the PTFE in the catalyst layer, and is not limited to ultrasonic vibration, and may also utilize, for example, the energy of laser light.

〔Effect of the invention〕

As explained above, according to the method of the present invention, communication between the electrolytic solution reservoir provided in the ribs of the porous electrode base material and the matrix is established using the repellent contained in the catalyst layer at the position corresponding to the electrolytic solution reservoir. This is done by removing water-based PTFE by thermal decomposition and making its molecular C' hydrophilic, which allows good permeability to vinegar solution. There is no need for the troublesome procedure of filling a hydrophilic material after forming holes or grooves, and there are advantages in that the number of manufacturing steps can be shortened and high accuracy can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view for explaining the structure of a fuel cell.

Claims (1)

[Claims] 1) After forming an electrolyte reservoir in the ribs of a porous electrode and providing a catalyst layer having a water-repellent fluororesin binder phase on the entire surface of the porous electrode opposite to the ribs. . A method for producing an electrode for a fuel cell, characterized in that the binder of the catalyst layer corresponding to the electrolytic solution reservoir is pyrolytically hydrophilic. 2. A fuel cell electrode manufacturing method according to claim 1, characterized in that the binder of the catalyst layer is thermally decomposed by ultrasonic vibration.