JPS6178067A - Fuel cell - Google Patents

Abstract

PURPOSE:To prevent flow-out and replenishment of electrolyte and improve cell characteristic by using cation exchange resin particles excessively bridged as electrolyte. CONSTITUTION:Strong acid cation exchange resin particle 10 are made electrolyte and the resin constituting resin particles 10 have bridge formation agent of 0.8-5 molar % as constituting compound. As the bridge formation degree of general strong acid cation exchange resin particles 10 is 8-10 molar %, the bridge formation degree of the above strong acid cation exchange resin particles 10 is relatively low. Then, they can be swelled well and can have better ion conductivity to prevent flow-out and replenishment of electrolyte, and cell characteristic can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention provides highly acidic cation exchange resin particles that have a low degree of crosslinking, have high water swelling properties, and are insoluble in water.
This article relates to a fuel cell using an electrolyte.

(Prior art) A fuel cell that uses a gaseous fuel such as hydrogen or a liquid fuel such as methanol or hydrazine, and a gaseous oxidant such as oxygen or air or a liquid oxidant such as hydrogen peroxide is used as a power source for each power source. It has been considered and has already been put into practical use.

Among such fuel cells, alkaline electrolyte fuel cells and acidic electrolyte fuel cells are known as those used in an atmosphere of about 100° C. or lower. The electrolyte used in these fuel cells is often caustic potash, caustic soda, an aqueous solution of lithium hydroxide, or dilute sulfuric acid.

This is because an aqueous solution of the strong electrolyte mentioned above is the easiest to use as an electrolyte with high electronic conductivity at low temperatures.

On the other hand, fuel cells using organic polymer electrolytes that dissociate in the presence of water as electrolytes are also known (W.
23473).

(Problems to be Solved by the Invention) In fuel cells using the above-mentioned strong electrolyte, the two strong electrolytes are highly corrosive, so not only are the constituent materials of the battery limited, but the electrolyte is It is necessary to be very careful not to leak. Therefore.

Measures against electrolyte leakage are essential.

In addition, when a liquid solute is used, if the fuel or oxidizer also becomes liquid, the electrolyte that should remain in the electrolyte chamber becomes porous due to the dilution phenomenon due to the concentration gradient between the liquid fuel or liquid oxidizer. A phenomenon occurs in which the fuel flows through the fuel electrode or oxidizer electrode into the fuel chamber or oxidizer chamber. As a countermeasure for this,
Generally, a method is adopted in which a fuel mixture diluted with an electrolyte is used in the fuel chamber to reduce the concentration gradient.

However, in this case, the concentration of fuel will be smaller.

Energy efficiency decreases (because more power is consumed circulating the electrolyte than fuel).

! Although it is possible to mix an inorganic powder into an acid solution to form a paste, this method is not a fundamental countermeasure since it passes through an IT electrolyte, a fuel electrode, or an oxidizer electrode.

In order to solve the above-mentioned problems, a fuel cell using an organic polymer electrolyte as two electrolytes has been proposed. This fuel cell is intended to solve the problems caused by using the electrolytic solution described above, and the present inventors have studied this in detail.

There are considerable differences in the properties of organic polymer electrolytes depending on their properties, and further improvement of their properties is desired in order to create an excellent fuel cell.

As mentioned above, fuel cells that use electrolyte.

Problems arise from the use of highly corrosive strong electrolyte materials. Fuel cells using organic polymer electrolytes are desired to have further improved characteristics.

(Means for Solving the Problems) The present invention is a device for directly extracting electrical energy by causing an electrochemical reaction between a fuel electrode and an oxidizer electrode that face each other with an electrolyte in between, in which the electrolyte is water The resin constituting the resin particles is strongly acidic cation exchange resin particles that dissociate in the presence of.

The present invention relates to a fuel cell using a resin having 0.8 to 5 mol of a crosslinking agent as a constituent component.

The strongly acidic cation exchange resin particles of the present invention are particles of a copolymer of a crosslinkable polymerizable monomer (crosslinking agent) and a non-crosslinkable polymerizable monomer. This product contains 0.8 to 5 moles of a crosslinkable polymerizable monomer, and a functional group such as a sulfonic acid group for forming the entire electrolyte is introduced therein.

Examples of the crosslinkable polymerizable monomer include divinylbenzene, divinyltoluene, divinylnaphthalene, divinylphenol, diallyl phthalate, diallyl heptafluoride, ethylene glycol dimethacrylate, and ethylene glycol diacrylate.

Examples of the non-crosslinkable polymerizable monomers include styrenic monomers such as styrene/l monoethylvinylbenzene, bi;letoluet/Iα-methylstyrene, and aliphatic monomers such as vinylnaphthalene, vinylphenanthrene, and imprene. Orefui/,
Ethyl acrylate, butyl acrylate, acrylic acid 2-
Acrylic esters such as hydroquine ethyl, methyl methacrylate.

Ethyl methacrylate, butyl methacrylate 1 methacrylate! J
methacrylic acid esters such as 2-hydroxyethyl chlorate;
Vinyl cyanide such as acrylonitrile and methacrylonitrile, dibasic diesters such as diethyl fumarate, vinylfuran, and vinyl imidazole. vinylphenol,
Vinylphenol acetate, vinyl acetate, etc.

Any polymerization method can be used to produce the above copolymer as long as it is a method of polymerizing a crosslinkable polymerizable monomer and a non-crosslinkable polymerizable monomer in the presence of a radical polymerization initiator. However, the most preferred is the aqueous @full-through method, in which particles of a desired particle size can be obtained by simply further classifying the particles upon completion of one polymerization.

Water-based 8 like this! As the turbidity polymerization method, for example, the method described in 1% Japanese Patent Publication No. 1983-94902 can be employed as a desirable method. aqueous'! @During the dry polymerization, the particles obtained become porous by the presence of a water-insoluble organic solvent such as toluene or inamyl alcohol. It is believed that porous particles have a favorable influence on the swelling of one particle and therefore on the ionization.

In the above production method, the degree of crosslinking is adjusted by the ratio of crosslinkable polymerizable monomer used, the prognosis is adjusted by the turbidity polymerization conditions, and the porosity is adjusted by the amount of the water-insoluble organic solvent used. can.

Among the above copolymers, styrene-divinylbenzene copolymer obtained by using divinylbenzene as a crosslinking polymerizable monomer and a styrene monomer as a non-crosslinking polymerizable monomer. Coalescence is particularly preferred because it facilitates the introduction of sulfonic acid groups and facilitates production.

For example, one method for introducing the above-mentioned functional group is as follows.

In order to introduce a sulfonic acid group, the above copolymer particles t-*
This is carried out by reaction with a sulfonating agent such as sulfuric acid or chlorosulfonic acid. Furthermore, during the production of the above copolymer, a sulfonated polymerizable monomer such as styrene sulfonic acid may be copolymerized.

The strongly acidic cation exchange resin particles preferably have an ion exchange capacity of 2 to smeq/g.

If the ion exchange capacity is too small, the ion conductivity will be too low, and if it is too large, it will be difficult to introduce functional groups. When a sulfonic acid group is introduced as a functional group, it is preferable to use a monomer having a benzene ring as a raw material for the above-mentioned copolymer in an amount that allows a suitable ion exchange capacity.

The strongly acidic cation exchange resin particles preferably have a dry particle size of 0.5 μm to 50 μm.

The smaller the particle size, the larger the surface area of the unit weight.
It has high ionic conductivity and is preferable as an electrolyte, but if it is too small, it becomes difficult to manufacture and the handling efficiency decreases. On the other hand, if the particle size is too large, the ionic conductivity tends to decrease.

The above-mentioned strongly acidic ion exchange resin particles may be used as is, but it is preferable to use them as a mixture with water.
In particular, it is preferable to form it into a paste form.

To form a base, the particles are dispersed in water at a high concentration, or an insulating inorganic powder such as fine silicon carbide powder or fine silica powder is mixed as a thickener into the water e-liquid of the particles. especially)

The fuel cell according to the present invention can be purchased as long as the fuel electrode and the oxidizer electrode face each other with an electrolyte in between.

Although there are no particular limitations, the following description will be made with reference to FIG. 1, which is a schematic diagram of a fuel cell according to the present invention.

゛Liquid fuel such as methanol or hydrazine or gaseous fuel such as hydrogen gas flows into the fuel chamber 1 from the fuel chamber 2, and oxidizers such as oxygen or air flow into the oxidizer chamber 3 from the desensitizer chamber. Supplied from 4. An electrolyte layer 7 and a diaphragm 8 are provided between the fuel electrode 5 and the oxidizer electrode 6. In the electrolyte layer 7, strongly acidic field ion exchange resin particles 10 having ionic groups 9 chemically bonded to one surface are present. Ionic group on particle surface 9
is the counterion LL'1i-Fl! in the presence of water. Release.

The counter ions 11 move within the electrolyte layer 7 as a result of the cell reaction and are consumed at the oxidizer electrode 6, but ions of the same type are generated at the fuel electrode 5 and replenished. Specifically, the counter ion 11 is a hydrogen ion because it is an acidic t7+1 substance. Although the diaphragm 8 is not necessarily required, the fuel is connected to the fuel electrode 5. When the oxidizer reaches the oxidizer electrode 6 through the electrolyte layer 7, it is likely to cause a cell reaction and be oxidized or burned, which is preferably provided to prevent or suppress a decrease in fuel efficiency.

Its position is not particularly limited as long as it is between the fuel electrode 5 and the oxidizer electrode 6. As the diaphragm 8, for example, a cation exchange membrane is used since the electrolyte is acidic. The cell reaction of a methanol fuel cell is as follows.

Fuel electrode (negative abrasive) CH30H+HzO-+CO2+6H"+66-Oxidizer electrode (positive electrode) '02+ 6H"+ 66-→3H20 Figure 2 shows the configuration of a single cell of a methanol/air fuel cell according to an embodiment of the present invention. FIG. 2 is a partially cutaway perspective view. This single cell consists of a graphite separator 12 that forms an air chamber and also serves as a photovoltaic body, an air electrode 132 adjacent to the separator 12, an ion exchange membrane 14, and a methanol electrode fixed to a holding frame 15. 16 and an electrolyte layer 17 applied or supported thereon.Separators 20 of Graphite IIJ, which also serve as a capillary structure, are sequentially stacked from the methanol tank 18. Grooves 21 are formed in the separators 12 to serve as air passages. It is easier to support the electrolyte on the methanol electrode etc. if it is in the form of a paste.
opposite side.

And/or by applying it to the opposing surface of the air electrode 15 and one or both surfaces of the ion exchange membrane 14, a thin electrolyte layer can be easily created. In addition, in the present invention, methanol is produced from the fuel tank to the fuel chamber, and in this case, a mixture of fuel and electrolyte (called an anolite) is supplied and circulated as in a conventional methanol battery that uses an aqueous solution of an electrolyte. Auxiliary mechanisms such as pumps can be eliminated. This not only simplifies the construction of batteries, but also increases the efficiency of energy use since no power is required. That is, in the present invention, since the electrolyte is a water-insoluble particle, it can pass through the porous fuel electrode, and therefore the electrolyte is not diluted, so there is no need to use an anorite as the fuel. Therefore, in this case, methanol can be used alone or with the addition of a small amount of water necessary for the reaction.

Sufficient methanol can also be supplied using the suction t method.

In addition, in FIG. 2, arrow A indicates the flow of air.

B is the flow of water vapor and air generated by the battery reaction, C
is the flow of fuel, D is the flow of carbon dioxide generated by the cell reaction, and E is the flow of carbon dioxide released from the cell.

FIG. 3 is a perspective view showing the appearance of an example of a fuel cell constructed by stacking the single cells shown in FIG. 2. If the electromotive force of a single cell is 0.6V, connecting 20 single cells in series constitutes a fuel cell with an electromotive force of 12V. In FIG. 3, the same symbols as in FIG. 2 have the same meanings. A large number of stacked cells are housed in a battery case 22, and a positive terminal 23 and a negative terminal 24 are attached. Fuel is supplied from the boat 25 to the fuel tank 26. In the above,
As the oxidizer electrode and the fuel electrode, porous electrodes such as carbon fiber nonwoven fabric are used.

(Function) The fuel cell according to the present invention is composed of 9 strongly acidic cation exchange resin particles as an electrolyte, and the resin constituting the resin particles has 0.8 to 5 mol of a crosslinking agent as a constituent component of the resin. use. Hereinafter, the proportion of the crosslinking agent in the resin will be referred to as the degree of crosslinking. Generally known strongly acidic cation exchange resin particles have a degree of crosslinking of 8 to 10 moles, so on the other hand, the degree of crosslinking of the strongly acidic cation exchange resin particles of the present invention is:
This is quite low. Therefore, it easily swells in water.

Good ionic conductivity and therefore good battery characteristics. When the degree of crosslinking is less than 0.8 molar, water-soluble polystyrene sulfonic acid is substantially present, so the problem of electrolyte leakage is worse, even if it is not as bad as sulfuric acid. If it exceeds 5 mol%, the swelling property becomes poor.

Ionic conductivity decreases. The degree of crosslinking is preferably:

It is 1.6 to 4 molti.

(Example) Actual legend 1 (1) Synthesis of electrolyte particles Thermometer, bimetallic relay, reflux condenser.

3 equipped with a homo mixer (Tabletop M type machine made by Tokushu Kika)
T! 179g of styrene in four separable flasks,
60% divinylbenzene (divinylbenzene 6 ol:
It means a mixture of 40 units of monovinylethylbenzene.

The same applies hereafter) 13G,) Chef 115g. Benzoyl peroxide (BPO') 10 g.

10 hardly soluble tricalcium phosphate (TCP) suspension 30
0 ml was added to 1,400 mJ' of ion-exchanged water, dispersed under stirring with high-speed shearing in a homomixer, heated to 70°C using a Nacala mantle heater, and polymerized for 1 hour while keeping the I2i temperature constant. Next, the reaction solution was quickly transferred to a four-necked 31 separable flask equipped with a thermometer prepared in advance, a metal relay, a reflux condenser, and an H-shaped blade stirrer, and the heavy metal content was maintained at 80-85℃. While stirring, the polymerization was further carried out for 4 hours at a stirring speed of 500 to 600 Q) m. The produced porous spherical particles were passed through the mouth, washed with dilute hydrochloric acid solution, and then dried. When these particles are observed under a microscope.

More than 50% of the samples had a diameter of 10 μm to 20 μm.

Total amount of the above particles and dichloroethane 3009°97% sulfur 1
Pour 200 ml of I21 into a flask and heat at 80°C on an oil bath.
The temperature was raised to 1, and the mixture was reacted for 4 hours to effect sulfonation. The sulfonated product was passed through the mouth, washed with water, acetone, and washed again with water to obtain strongly acidic cation exchange resin particles for electrolyte. The ion exchange capacity of this product was 4.3 meq/g (degree of crosslinking 3.3 molti).

(2) Fuel cell resin particles (A suitable amount of silicon carbide e powder was added as a thickener to the aqueous dispersion of step 11 and kneaded well to obtain a paste-like electrolyte. This paste-like electrolyte was used as a second A single cell of a fuel cell was obtained by interposing it in the electrolyte holding frame 15 between the methanol electrode 16 and the cation exchange membrane 14 shown in the figure.The current (Il-voltage) of this single cell is shown in FIG. Ta.

By making the electrolyte a water-insoluble, granular, strongly dispersible cation exchange resin, the electrolyte does not pass through the electrodes and leak out to the outside, making it easier to handle and allowing for long-term operation. However, the battery output no longer decreases. Ninth, the strongly acidic cation exchange resin particles have appropriate swelling properties.

The battery characteristics were very good. Furthermore, since the electrolyte no longer flows out into the fuel chamber, there is no need to mix all the electrolyte into the fuel, and as a result, in the stacked battery shown in No. 311, there is no short circuit between the electrodes for supplying only fuel, and the fuel This eliminates the need for a supply pump, improving battery output and fuel efficiency.

Fuel supply made easy.

Example 2 (1) Synthesis of electrolyte particles The same reaction as in Example 1 was carried out except that 6.5 g of styrene 1869.60% divinylbenzene was used, and styrene-monovinyl ethylbe/ze/-sivinylpe/zene copolymer resin particles were prepared. (50% or more of the particles had a particle size of 10 μm to 20 μm). This product was further reacted in the same manner as in Example 1 to obtain strongly acidic cation exchange resin particles fnl for electrolyte. The ion exchange capacity of this product was 4.3 meQ/g, and the degree of crosslinking was 1.6 mol%.

(2) 1 liter of fuel cell resin particles were made into a paste-like electrolyte in the same manner as in Example 1 (2), and a single cell was constructed. The current (I)-voltage (■ characteristics) of this single cell are shown in FIG. 5. This electrolyte also did not flow out to the outside of the electrode, as in Example 1 (2).

There was also no decrease in battery output. Furthermore, the battery characteristics were also excellent.

Comparative Example 1 (1) IT Electrolyte Particle Synthesis The same reaction as in Example 1 was carried out except that 32 g of styrene 1609.60% divinylbenzene was used.
Divinylbenzene resin particles (particle size 10 μm to 20 μm
50 inches or more). This product was further reacted in the same manner as in Example 1 to obtain strongly acidic cation exchange resin particles for electrolyte (0ff). The ion exchange capacity of this product is 4.
It was measured at 3 meQ/g (degree of crosslinking 8.3 mol).

(2) Combustion battery resin particles (III) were prepared in the same manner as in Example 1 (2) to form paste 1! It was made into L solute and a single cell was constructed. The current fI)-voltage Y)% characteristic of this single cell is shown in FIG. Because this electrolyte has a high degree of crosslinking, its internal resistance was quite large, resulting in poor battery characteristics.

(Effects of the Invention) By using appropriately cross-linked cation exchange resin particles as an electrolyte, the fuel cell according to the present invention not only eliminates problems of electrolyte outflow and replenishment, but also exhibits excellent cell characteristics. .

[Brief explanation of drawings]

Fig. 1 is a schematic diagram for explaining the principle of the fuel cell of the present invention, Fig. 2 is a partially cutaway perspective view showing the configuration of a single cell of the fuel cell according to the present invention, and Fig. 3 is a schematic diagram for explaining the principle of the fuel cell of the present invention. A perspective view showing the structure of a connected fuel cell, and FIGS. 4 to 6 are graphs showing current-voltage characteristics of a single cell of a fuel cell according to an example of the present invention and a comparative example. Explanation of symbols 1...Fuel chamber 2...Fuel chamber population 3...
・Oxidizer chamber 4... Oxidizer chamber population 5... Fuel electrode 6... Oxidizer electrode 7... Electrolyte layer
8... Diaphragm 9... Ionic group 10... Strongly acidic field ion exchange resin particles 11... Counter ion/ 12... Separator 13... Air electrode 14... Ion exchange membrane 15...・Holding frame 16...methanol pole 21...4
22...Battery case 23...Positive terminal
24...Negative terminal 25...Fuel boat
26... Fuel tank A... Flow of incoming air B... Flow of released water vapor and air C... Flow of fuel D... Flow of carbon dioxide produced E... Flow of released carbon dioxide tl , Meta/-Rutsun 7 ¥3, 14 mouth current (-47S-) - Rod 5 (2) Electric; t5Pj(%Anti)-

Claims (1)

[Scope of Claims] 1. A device that directly extracts electrical energy by causing an electrochemical reaction between a fuel electrode and an oxidizer electrode that face each other with an electrolyte in between, in which the electrolyte dissociates in the presence of water. Strongly acidic cation exchange resin particles, wherein the resin constituting the resin particles contains a crosslinking agent as a constituent component of the resin from 0.8 to 0.8%.
A fuel cell containing 5 mol%. 2. The fuel cell according to claim 1, wherein the strongly acidic cation exchange resin particles are sulfonated copolymer particles.