JPS612276A - Fuel cell - Google Patents

Abstract

PURPOSE:To uniformly supplement electrolyte to an electrolyte matrix to suppress decrease in cell performance by combining an electrode with rib with a porous plate having high electrolyte retaining ability and a separator for electrolyte supplement. CONSTITUTION:To uniformly supplement electrolyte to a unit cell comprising a negative electrode 2, a positive electrode 3, and a matrix 4, an electrolyte diffusion plate 6, an electrolyte supplement separator 7, and a gas separating separator 8 are stacked in order. electrolyte supplied to an electrolyte supplement channel 10 in the electrolyte supplement separator 7 is passed in an electrolyte supply hole 11, and diffused to the electrolyte diffusion plate 6 and stored there. Then, the electrolyte passes through the electrode 2, and is uniformly supplied to the electrolyte matrix 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a fuel cell in which a separator is provided with an electrolyte replenishment channel, and an electrolyte matrix can be uniformly replenished with an electrolyte from the channel.

[Prior art and its problems]

Conventional fuel cells are single cells with an electrolyte matrix sandwiched between the negative electrode (fuel electrode) and the positive electrode (air electrode).
The above-mentioned unit cells are stacked with one layer between each other. A part of a conventional stacked fuel cell is shown in FIG. (1) is a separator, (2) is a negative electrode (fuel electrode), (31 is a positive electrode (air electrode), (41 is a matrix).

Conventional fuel cells have a structure in which the electrolyte is held only in the IJ sock, so the amount of electrolyte contained in the matrix is limited. During battery operation, the electrolyte contained in the matrix is carried out of the battery. Due to the above reasons, as the operating time elapses, the flow of the electrolyte contained in the matrix decreases, and the conductivity of the electrolyte matrix is low, resulting in a gradual decline in battery performance. Currently, in order to improve the above-mentioned drawbacks, ribbed @
A method has been considered in which the electrolyte is replenished into the matrix by using electrodes to hold the electrolyte or by forming grooves in the separator to hold the electrolyte. However, the above-mentioned improved battery had a drawback in that the electrolyte solution could not be uniformly replenished into the electrolyte matrix.

[Purpose of the invention]

The present invention improves the above-mentioned drawbacks of conventional fuel cells, and aims to uniformly distribute the electrolyte into an electrolyte matrix.

[Summary of the invention]

The present invention uses a porous plate made of carbon as a negative electrode, with trap grooves on one side and a catalyst layer formed on the other side.
A ribbed electrode or a smooth thin carbon electrode is used as the positive electrode, and an electrolyte matrix is sandwiched between the positive and negative electrodes, and the unit cell is placed with the negative electrode facing upward. A fuel cell characterized in that it is formed by repeatedly stacking a conductive smooth porous plate with high electrolyte holding power (percent layer liquid diffusion plate), a separator for electrolyte replenishment, and a separator for gas isolation in this order. It is.

〔Effect of the invention〕

According to the present invention, it is possible to uniformly replenish the electrolyte solution (IJ sock electrolyte), and it is possible to obtain the effect that deterioration of battery function can be suppressed.

[Embodiments of the invention]

The second exploded perspective view of the single cell component of the fuel cell of the present invention is shown in FIG.
As shown in the figure.

In order to uniformly replenish the electrolyte to the unit cell with the matrix (4) sandwiched between the negative electrode (fuel electrode) (2) and the positive electrode (air electrode) (3), an electrolyte diffusion plate (6), an electrolyte A liquid replenishment separator (7) and a gas isolation separator 18) were placed in this order.

The electrolyte diffusion plate (6) is for uniformly replenishing the matrix with electrolyte and has the following properties.

(1) Edible type conductivity (II) High electrolyte holding power (UL acid resistance.

The electrolyte replenishment separator (7) is provided with a channel for replenishing the electrolyte. Furthermore, an external electrolyte replenishment port (9) is provided at the corner for introducing rectangular solution into the electrolyte replenishment channel from outside the battery. A gas isolation separator (8) is inserted to prevent fuel gas and air from mixing.

FIG. 3 shows a view of the electrolyte replenishment separator (7) viewed from the gas isolation separator (8) side. In addition, the separator (7) for replenishing the layer liquid is grooved to provide a channel for replenishing the electrolyte. An internal electrolyte replenishment port aυ leading to the electrolyte diffusion plate (6) is opened at the bottom of the channel (1).In the figure, two external electrolyte replenishment ports (9) are provided, but this Up to 4 locations are possible.

FIG. 4 shows a sectional view of a single cell of the fuel cell of the present invention. The electrolyte led to the electrolyte replenishment channel (1α) provided in the electrolyte replenishment separator (7) is connected to the internal electrolyte replenishment port (
1υ, diffuses into the electrolyte diffusion plate (6), and is stored. The phosphoric acid then passes through the ribbed electrode (2) and is uniformly supplied to the 1(L solute matrix (4)).

It's 1, 'r8. In the solution sleeve layer liquid separator (7), fuel gas and air mix because the internal electrolyte storage ITI (II) is open. For this reason, the electrolyte replenishment separator (7
) and the positive electrode (3) are (1) erodible conductive (1) airtight (111) acid resistant.

With this configuration, it is possible to replenish the electrolytic solution to the electrolytic η matrix by inserting the electrolyte replenishing channel (1 (0) separator (7) for electrolyte replenishment). When there is 1 frost, the electrolyte is introduced from the outside of the pond to the electrolyte diffusion plate 1 channel θO) by attaching the plow and 1 layer liquid replenisher (9) to the corner of the valator. It is now possible to easily replenish the electrolyte matrix.

Next, the effects of the electrolyte diffusion plate (6) will be described below. In the conventionally proposed fuel cell in which the separator is used as the electrolyte reservoir, the electrolyte diffusion plate (6) is connected to the separator (7) and the negative electrode (
Since it was not inserted between the separator (7) and
) must be aligned so that the internal electrolyte replenishment port Ql) and the rib part of the negative electrode (3) are in contact with each other, which is very difficult to process, and because the number of holes is limited, the electrolyte cannot be uniformly distributed. The matrix is not resupplied. In the present invention, by inserting the electrolyte diffusion plate, alignment of the holes of the internal electrolyte supply port αυ becomes unnecessary, and moreover, it becomes possible to uniformly supply the electrolyte to the matrix.

For the above reasons, the amount of electrolyte in the electrolyte matrix can be kept constant, and a battery with stable characteristics, high performance, and long life can be obtained.

More specific examples of the present invention will be described below.

As an example of the present invention, a 110×10 cell was fabricated. A graphite sheet (Nika Film 9 manufactured by Nippon Carbon) was used as the gas isolation separator (8).

The plate thickness of the separator (8) is approximately 0.3 cavities.

The electrolyte replenishment separator (7) was made of a graphite plate with a thickness of about 5 fins and was grooved as shown in FIG. The external electrolyte replenishment port (9) is threaded and sealed except when replenishing the electrolyte. Internal electrolyte supply port α1) has a diameter of 1α],
The hole was about 5 rvn.

A carbon sheet made of the same material as the porous carbon used in the negative electrode (2) was used as the electrolyte diffusion plate (6). Carbon black (product name:
VXC72R) was impregnated. The impregnation method was as follows. A carbon blank was dispersed in water, a porous carbon sheet was immersed in the dispersion, and after the carbon black had sufficiently penetrated, it was dried. The thickness of the porous carbon sheet is about 2 mm.

Using the above-mentioned gas isolation separator (8), electrolyte replenishment separator (71, 1i) and solution diffusion plate (6), a unit cell with the structure shown in Fig. 2 was fabricated, and a current density of 1 at normal pressure and 205°C was prepared.
Operation was performed under the condition of 60 mA/cy+f. In addition, 10
00 hours, add 2 liters of electrolyte from the external electrolyte replenishment port (9).
ml supplemented. The above results are shown in FIG.

(5) shows the cell characteristics of the fuel cell of the present invention, and (B) shows the cell characteristics of the conventional fuel cell. Battery characteristics of conventional fuel cells (B)
In the fuel cell of the present invention, the cell characteristics rapidly deteriorated after approximately 4000 hours of operation, whereas in the fuel cell of the present invention, almost no deterioration in the cell performance was observed.

[Other embodiments of the invention]

In the above embodiment, a graphite sheet was used as the gas isolation separator (8), but other materials such as metal sheets such as tank plates may also be used.

The type of the electrolyte replenishment channel (10) provided in the electrolyte replenishment separator (7) can be easily conceived other than the type shown in the embodiment. Separators (7) with other types of electrolyte replenishment channels 00) are also within the scope of the invention.

Although FIG. 2 shows an example in which both the positive and negative electrodes use rifted electrodes, a thin carbon electrode can also be used for the positive electrode. FIG. 6 shows an exploded perspective view of a fuel cell using thin carbon electrodes. (121 is a thin carbon electrode 0 with a catalyst layer formed on one side; a is a separator with grooves.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a conventional fuel cell, Fig. 2 is an exploded perspective view of a fuel cell according to an embodiment of the present invention, and Fig. 3 is an electrolyte replenishment of the embodiment of the present invention shown in Fig. 1. FIG. 4 is a cross-sectional view of the embodiment of the present invention shown in FIG. 1, FIG. FIG. 3 is a perspective view of another embodiment of the invention. 2... Negative electrode, 3... Positive electrode, 4... Matrix,
6. Electrolyte diffusion plate, 7. Electrolyte replenishment separator,
8...Separator for gas gap 1.171, 9...External '1 (solution supply), 10-Panel F+T?ik supply channel, 11...Internal electrolyte supply port. Agent Patent Attorney Kensuke Chika (and 1 other person) Fig. 1 Fig. 2 Fig. 3 Fig. 4 (4 sides) Metto 10A

Claims (3)

[Claims] (1) As the negative electrode, an electrode (ribbed electrode) with grooves formed on one side of a carbon-based porous plate and a catalyst layer formed on the other side is used, and as the positive electrode, a ribbed electrode or a smooth thin electrode is used. Using a carbon electrode, an electrolyte matrix is sandwiched between the positive and negative electrodes.The unit cell is placed with the negative electrode facing upward, and a conductive, smooth porous plate with high electrolyte retention capacity is placed on top of the unit cell. liquid diffusion plate), electrolyte replenishment separator,
A fuel cell characterized in that it is formed by repeatedly stacking gas isolation separators in this order. (2) The gas isolation separator is an airtight, conductive plate, and the electrolyte replenishment separator is provided with an electrolyte replenishment channel that is grooved from the side of the gas isolation separator. Claim 1, characterized in that an external electrolyte replenishment port for guiding electrolyte from outside the battery to the replenishment channel is provided at at least one corner of the four corners of the electrolyte replenishment separator. The fuel cell described. (3) A patent characterized in that an internal electrolyte replenishment port for replenishing electrolyte from the electrolyte replenishment channel provided in the electrolyte replenishment separator to the electrolyte diffusion plate is provided at the bottom of the electrolyte replenishment channel. A fuel cell according to claim 1.