JPH01154468A - Liquid fuel cell - Google Patents

Abstract

PURPOSE:To prevent electrolyte leakage and to decrease short circuit caused by an electrolyte by using a rib-installed electrode comprising a porous carbon substrate in one electrode, and lowering the ends of the ribs at the ends of the electrode. CONSTITUTION:A rib-installed electrode 3-3 comprising porous carbon substrate is used as one electrode, and cuts 10-1 are installed in the end rib 7-6 to lower them than middle ribs 7-5. The side where electrolyte leakage may arise is easily covered with an adhesive sheet or tape, and step difference at the edge between an electrolyte layer and a flat separator 9-2 is eliminated to make the assembly of a unit 15 easy. The sealability is moreover increased by forming the end of the electrode with a dense layer or two color plastic. When the unit 15 is assembled, the electrolyte layer is shortened than the rib-installed electrode and a filler is packed. Short circuit caused by electrolyte and electrolyte leakage are prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fuel cell using liquid as fuel, and particularly! Seal and liquid short circuit prevention when using electrodes suitable for reducing R+
Regarding h.

[Conventional technology]

An example of a conventional fuel cell that uses liquid as fuel is shown in Figure 2 (Journal of the Institute of Electrical Engineers of Japan Vol. 104, Na), P. 42.
(Sho 59-1.)). The figure uses hydrazine as fuel, and has a frame 1-1 for holding an alkaline electrolyte, and a flat fuel electrode 2-1-1 with terminals 2-2 on both sides.
1 and air ji@2-1-2 are placed. Furthermore, a fuel chamber 3-3- and an air chamber 3-2 are arranged on the outside thereof, respectively. This method is called an internal manifold, and the fuel (
Supply liquid 4 of a mixture of electrolyte and fuel called anolyte
-1 and exhaust liquid 4-2, as well as passages for air supply gas 5-1 and exhaust gas 5-2, are provided within the frames constituting the fuel chamber 3-1 and the air chamber 3-2. Further, the generated gas 6 is discharged from the upper part of the fuel supply system. in this way,
The electrode is a flat plate made of sintered metal, with a catalyst attached to a hole. This results in an increase in weight.

FIG. 3 shows another known example. The figure shows a fuel cell that uses methanol as fuel and uses an acidic electrolyte.
2, a fuel electrode 2-. 1-1 and air electrode 2-1-2 are combined to form a fuel chamber 3-1 on the outside of each, and have an intermediate rib portion 7-1 and an end rib portion 7-2 that function as current collectors. There is a separator 8, and a ribbed carbon separator 8 which forms an air chamber 3-2 and has an intermediate rib part 7-3 and an end rib part 7-4 that serve as current collectors, and these are laminated in several layers. be done. Fuel supply liquid 4-1 and discharge liquid 4
-2 is carried out through the fuel chamber 3-1-, and the generated gas 6 is discharged from the upper part. Further, the air supply gas 5-1 and exhaust gas 5-2 are passed through the air chamber 3-2. Since it is an acidic electrolyte, inexpensive metals cannot be found as electrode substrates, and the electrode base is composed mainly of carbon. In this case, the electrode substrate is porous and light, but the airtight ribbed carbon separator 8
Due to the processing involved, it is difficult to make the product thinner, which causes an increase in weight.

As described above, it is generally difficult to achieve weight reduction in fuel cells that use liquid as fuel.

On the other hand, in a phosphoric acid fuel cell that uses gas as fuel, for example hydrogen gas,
4, P, 162 (Sho 6O-11)), a fuel electrode 2-3-1 and an air electrode 2-3-2 with ribs made of a porous carbon substrate are used with an electrolyte 1-3 interposed between them. has been done. The hydrogen fuel supply gas 4-3 is discharged as exhaust gas 4-4 through the fuel chamber 3-3-1 between the intermediate ribs 7-5-1 provided on the fuel electrode 2-3-1. Further, the air supply gas 5-3 is supplied to an intermediate rib 7-5 provided on the air electrode 2-3-2.
-2 is discharged as exhaust gas 5-4 through the air chamber 3-3-2. Current collection is carried out from the intermediate rib portion 7-5 and end rib portion 7-6 of each electrode through an airtight flat plate separator 9-1. In this structure, the flat plate separator 9-1 can be made thinner and the porous ribbed electrode 2-3 can be made lighter, so that the overall weight can be reduced.

[Problem that the invention seeks to solve]

In the prior art, no consideration was given to the weight of the liquid fuel cell, resulting in an increase in weight.

However, there were problems in that it was difficult to reduce the weight due to short circuits and liquid leakage caused by the electrolyte.

An object of the present invention is to solve these problems and achieve weight reduction.

[Means for solving problems]

In conventional liquid fuel cells, the electrodes are plate-type, and the metal combustion plate increases the weight.If a porous carbon plate is used, a carbon separator with ribs is used, which increases the weight of the entire battery. It was as high as 60-70%.

Therefore, a ribbed electrode made of porous carbon as shown in FIG. 4 can be considered, but the fuel is liquid,
One of the major causes is that short circuits caused by the electrolyte are unavoidable because the anolyte mixed with the electrolyte is supplied to the fuel chamber, and the technology to prevent this is difficult. The other method uses liquid, so it does not work as well as gas only, and there is a problem with end sealing. This 2
The biggest reason is that the points have to be resolved.

However, in order to solve this difficulty, the rib part of the ribbed electrode end was processed to make it easier to seal.
By adopting an external manhold method and installing a partition plate inside the manifold, and by using a gel-like organic polymeric acid as the electrolyte instead of using an electrolyte, damage to the electrodes and power loss by adult animals is prevented. I did it like that.

Furthermore, in order to prevent liquid leakage, the sealing performance is improved by applying resin coating or impregnation hardening to the end of the ribbed electrode, making the end a dense composition by two-color molding, or using plastic injection molding. do.

Furthermore, when combined with an integrated electrode and electrolyte unit or a flat separator, the sealing performance can be improved by applying pateya resin filling or coating.

[Effect]

As shown in FIG. 1, a notch 10-1 is made in the end rib portion 7-6 of the porous ribbed electrode 2-3 to make it lower than the intermediate rib portion 7-5. As shown in Figure 5, the adhesive sheet or tape 12-1 can be used to easily cover the side surfaces that are prone to leaking, such as the electrolyte layer 1-2 or the flat separator 9.
-2, there is no step at the end, making it easy to assemble the unit 15.

In addition, the sealing performance can be further improved by forming the electrode end with a dense layer or two-color molding of plastic.

Next, when assembling the unit 15, the electrolyte is made shorter than the ribbed electrode and padded to prevent a short circuit between the liquid seal and the electrode. At the same time, as shown in Figure 8, if one side is not a ribbed electrode, leakage can be prevented by applying a seal covering the electrolyte layer 1-2 of the unit 15 and both electrodes with an adhesive sheet or tape. . On the other hand, in order to prevent liquid short circuits, as shown in Fig. 12, an external fuel supply manifold is adopted, and a partition plate 22 is provided inside this manifold to restrict the liquid passage, thereby preventing damage to the electrodes and power loss. can be suppressed.

Furthermore, in order to completely eliminate this liquid short circuit, the greatest improvement is not to use an electrolyte, and by using a polymer electrolyte, the above objective can be achieved by simply supplying a mixture of fuel and water.

[Example] Hereinafter, an example of the present invention will be described with reference to FIG. The figure shows a porous ribbed carbon electrode 2-3.

The catalyst is attached to the flat surface on the opposite side from the ribs.Therefore, in order to improve sealing performance, cuts 10-1 are provided in the electrode end rib portion 7-6 on both sides. In the figure, an intermediate rib portion 7-5 is formed that constitutes a chamber 3-3 for supplying fuel and air. In addition.

The figure can be used for both fuel electrode and air electrode applications. Still another embodiment is shown in FIG. 5, in which the ribbed electrode 2-3
A notch 11-1 is also made in the end rib part 7-6 and the flat surface end where the catalyst layer is located, and the entire end is covered and sealed with adhesive tape or sheet 12-1. .

Next, as another example, as shown in FIG. 6, the end portion 7-6 of the ribbed electrode 2-4 is molded with resin 13-1, which is more effective in preventing liquid leakage from there. be. Instead of resin mold 13-1.

Needless to say, sealing properties can be obtained by resin coating, plasticization by two-color molding, or airtightness using carbon material.

Next, another embodiment is shown in FIG.
2 and both electrodes 2-4 are configured as a unit 15.

In the same figure, the fuel supply system runs from the bottom to the top of the fuel electrode 2 on the right.
-Fuel chamber 3-3 formed by rib portion 7-5-1 of 4-1
-1. The air supply system runs from the front to the back through an air chamber 3-3-2 formed by the rib portion 7-5-2 of the left air electrode 2-4-2.

The end portion of each electrode is sealed by the method shown in FIG. 5 above. To combine the electrolyte layer 1-2 and both electrodes 2-4 into a unit 15, as shown in FIG.
Although it is shortened, it is made so that it covers the end seal portion 12-1 of the ribbed electrode 2-4, thereby preventing a liquid short circuit between the electrodes.

In this state, the resin filling 14-1 is performed to prevent liquid leakage. The situation when unit 15 is combined is shown in the same figure (a
) is as follows.

Furthermore, when forming the unit 15, if the one side is a conventional flat electrode 2-1-1, as shown in FIG. This enables an even stronger seal to be applied. Although FIG. 8 shows the case where the ribbed electrode is an air electrode, the opposite may be used. Another embodiment of unit 15 is shown in FIG. This example has a structure in which fuel is supplied from a fuel tank provided on the side of the fuel electrode 2-1-1. In this case, after each end of the electrode is sealed 12-1, when forming the unit 15, the electrolytic lα layer 2-1 and both electrodes are integrally sealed 17-]- at one end shown in the figure. can do.

Next, FIG. 10 shows an embodiment of the seal including the separator 9-2.

A flat separator 9-2 is placed on both sides of the unit 15 of the embodiment shown in FIG.
This is an example in which 1-1 is made a little larger and resin or putty 16-1 is applied to this gap. With this as the basic structure, multiple cells can be stacked together to form a fuel cell.

This situation is shown in FIG. 1J, where the fuel (mixed with electrolyte) 4-1 is supplied and the drained liquid 4-2 is circulated through the fuel supply manifold 18. Air 5-1 passes through manifold 18-3 and is discharged as exhaust gas 5-2.

The inside of this fuel supply manifold 18 has a structure as shown in FIG. 12 in order to prevent short circuits caused by the electrolyte. In this example, two cells of the unit are collectively partitioned by a partition plate 22 inside the manifold 8-1.

This is fixed to the manifold outer lid with 23 pieces of putty. Note that the fuel anolite 4-1 is connected to the fuel supply port 24.
Supplied by Manifold 8-2 with fuel outlet
has a similar structure.

In addition, in FIG. 12, cooling air holes 21 are provided for every two cells.
The air volume is adjusted according to the accuracy of temperature rise.
This allows fuel cells to operate at a constant temperature.

Next, FIG. 13 shows another embodiment for preventing liquid short circuit.

This figure shows an attempt to fix the electrolyte without using an electrolyte (such as sulfuric acid) mixed with the fuel. By doing so, only a mixture of fuel and water can be supplied, and the partition plate 22 inside the manifold 8 as described above is not only unnecessary, but also the sealing performance is much better than when an electrolyte is used.

An example of the embodiment is shown in FIG. 13, and the electrolyte layer 1
-2-1 In the acid type, a gel-like organic polymeric acid having a sulfonic acid group, which is a strong acid, is used. These include copolymers in which the base resin is styrene, fluorocarbon, styrene-divinylbenzene, styrene-butadiene, or the like. If the degree of crosslinking is high, it will become hard like an ion exchange membrane, so it is preferable that the membrane be crosslinked to the extent that ions are dissociated in the presence of water but not eluted, resulting in a gel-like state.

Furthermore, in order to perform ion conduction in the catalyst layer (2-4-1, 1, 2-4-22), -1=, in addition to the same material as described above, a polyphosphoric acid-based condensation material is impregnated or mixed. An electrolyte 20 is formed in the catalyst layer. This allows fuel cells to achieve high performance without the use of electrolytes.

〔Effect of the invention〕

According to the present invention, it is possible to prevent fluid leakage from a fuel cell string using a liquid using a ribbed electrode, and in addition, it is possible to significantly reduce or eliminate short circuits caused by electrolyte, which can cause electrode damage and power loss. be able to.

Although ribbed electrodes have been used for gas fuels such as hydrogen fuel, it was considered impossible or extremely difficult to create fuel cells that use liquid fuel, but this has been achieved through the present invention, and now methanol 60 to 70 of the main body with fuel cells
Since a thin plate separator can be used in place of the ribbed separator, which accounts for 30% of the total weight, it is possible to reduce the weight by 60% or more. Therefore, it is expected that its use as a general-purpose product will expand.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a ribbed electrode showing an embodiment of the present invention;
Figures 2 and 3 show the unit configuration of a conventional example. Figure 4 shows the unit configuration of a conventional example of a hydrogen gas fuel fuel cell. Figures 5 and 6 show the invention. Figures 7 to 9 are diagrams showing a unitized embodiment of the present invention, Figure 10 is a diagram in which a separator is configured in the unit, and Figure 11 is a diagram showing a ribbed electrode showing another embodiment of the present invention. 12 is a cross-sectional view of the inside of a fuel supply manifold, and FIG. 13 is a diagram showing the principle of a unit in which electrolyte is immobilized. 7-6... Rib part of the end of the ribbed electrode, 10-1...
Notch made in the rib part of the end of the ribbed electrode, 11-1
...Notch made on the opposite side of the ribbed electrode end, 1
2-1... Adhesive tape or sheet, 13-1...
・Resin mold for the end of the ribbed electrode, 14-1... Filler between the electrolyte layer and both electrodes, 15... Unit. 16...Resin or putty-like filler for sealing between units and separators, 17-1...Adhesive tape or sheet for sealing ends between units, 18-1゜2...
Fuel supply and discharge manifold, 18-2... Air supply manifold, 1-2-1... Polymer M [first (2nd
1 Chiga 2 Figure Otsusuke Figure 4 Kaya S Figure 4 Figure 1'o-u] I21 (to) (lD) Old Figure 3 ■■ T-1 Figure 9 Figure 10 Figure 11 ↑ ↑

Claims (1)

[Claims] 1. In a fuel cell using liquid as fuel, a ribbed electrode made of a porous carbon base is used as at least one of the fuel electrode and the air electrode, and the ribbed portion at the end of the electrode is used. A liquid fuel cell characterized by having a lower end. 2. The liquid fuel cell according to claim 1, characterized in that the electrode end is sealed with an adhesive sheet or tape by utilizing the lowered end of the rib portion of the electrode end. 3. A liquid fuel cell according to claim 1, characterized in that a high-density layer is formed on the rib portion of the electrode end by resin impregnation or resin coating, or by two-color molding. 4. In any one of claims 1 to 3, after assembling both electrodes via an electrolyte layer, the three layers are sealed together with an adhesive sheet or tape at the end. A liquid fuel cell characterized by being sealed and unitized with a resin coat. 5. In any one of claims 1 to 4, a separator is stacked on a unit in which an electrolyte layer and both electrodes are integrally sealed, and the ends are sealed with a resin coating or a pawl. A liquid fuel cell featuring: 6. A liquid fuel cell according to any one of claims 1 to 5, characterized in that after laminating a plurality of units and separators, external manifolds for fuel supply and air supply are attached. 7. A liquid fuel cell according to any one of claims 1 to 6, characterized in that the inside of the fuel supply manifold is divided into 1 to 3 units by partition plates. 8. A liquid fuel cell according to any one of claims 1 to 6, characterized in that the electrolyte in the electrolyte layer or the electrode catalyst layer is a gel-like organic polymeric acid.