JPH0817469A - Organic electolytic battery - Google Patents

Abstract

PURPOSE:To enhance the high temp. preserving performance to a great extent by using as electrolyte an organic solvent solution of tetraalkyl ammonium salt including a methyl radical as either of the alkyl radicals. CONSTITUTION:A coin type organic electrolyte battery includes an organic electrolyte which is an organic solvent solution of tetraalkyl ammonium salt as expressed by the chemical equation given beside the text. Either of R1-R4 in the equation should be methyl radical while the other three are ethyl radical, and X represents a negative ion residual radical of the tetraalkyl ammonium salt. As the electrolyte, a 1-mol/l solution of CH3(C2H5)3NBF4-propylene carbonate is used, and with this the electrode is impregnated. This allows suppressing increase of the internal resistance even under high temp. preservation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small-sized and large-capacity coin-type (button-type) organic electrolyte battery using an organic semiconductor containing a polyacene-based skeleton structure as an electrode.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Application Publication No. Sho.
0-170163 discloses an organic electrolyte battery in which an organic semiconductor (hereinafter referred to as PAS) containing a polyacene skeleton structure is used as a positive electrode and a negative electrode, and an aprotic organic solvent solution is used as an electrolytic solution. The battery has the features of high capacity, long life and excellent safety, but many problems remain when it is put into practical use as a coin type (button type) battery.

In particular, in the electrical characteristics after storage at high temperature (70 ° C., 2.5 V applied), there was a problem that the internal resistance was greatly increased as compared with the value before storage at high temperature.

[0004]

DISCLOSURE OF THE INVENTION As a result of intensive studies conducted by the present inventors in view of the above-mentioned problems, they found that the problems of the above-mentioned existing techniques can be solved by using a specific electrolytic solution. Is a coin type (button type) that has excellent high temperature storage characteristics.
To provide batteries.

[0005]

A coin-type organic electrolyte battery including a positive electrode can, a positive electrode and a negative electrode composed of an organic semiconductor containing a polyacene skeleton structure, a separator, a negative electrode can, and an organic electrolytic solution. An organic electrolyte battery in which the organic electrolytic solution is a solution of a tetraalkylammonium salt represented by the following formula in an organic solvent.

Embedded image (However, in the formula, R ₁ , R ₂ , R ₃ , R ₄ and X are the same as above.)

The electrolytic solution used in the battery of the present invention is a solution of the above-mentioned tetraalkylammonium salt dissolved in an organic solvent, and it is desirable to prepare a solution after sufficiently drying and purifying each. As the organic solvent, an aprotic organic solvent is preferable, and use of propylene carbonate or a mixed solvent of propylene carbonate and ethylene carbonate is particularly preferable because the withstand voltage of the battery can be set high. The electrolytic solution is adjusted to a concentration of at least 0.5 mol / l or more, particularly preferably 0.8 to 1.5 mol / l.

What is important in the present invention is a tetraalkylammonium salt in which any one of the alkyl groups represented by the above chemical formulas R _{1 to} R ₄ is a methyl group and the remaining three are ethyl groups, that is, monomethyltriethylammonium tetrafluoro. Borate [CH ₃ (C ₂ H ₅ ) ₃ NBF
₄ ] is used as an electrolyte. When the PAS electrode described later is used for the positive electrode and the negative electrode, when monomethyltriethylammonium tetrafluoroborate is used as the electrolyte, the temperature is higher than that when tetraethylammonium tetrafluoroborate [(C ₂ H ₅ ) ₄ NBF ₄ ] is used. The increase in internal resistance after storage is significantly suppressed. Also,
Examples of the anionic residue represented by the chemical formula X ⁻ include BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , AsF ₆ ⁻ , Sb.
F ₆ ⁻ , CF ₃ SO ₃ ^{− and the} like can be mentioned.

The electrode applied to the present invention is a heat-treated product of a condensate of an aromatic hydrocarbon compound and an aldehyde described in JP-A-60-170163, which is filed by the same applicant as the present application. And an organic semiconductor having a polyacene-based skeleton structure in which the atomic ratio of hydrogen atoms / carbon atoms is 0.05 to 0.5. The organic semiconductor needs to have a specific surface area by the BET method of at least 600 m ² / g in order to efficiently promote the electrode reaction. In order to use the organic semiconductor as an electrode, it may be used as it is, or may be powdered and then used with a suitable binder material,
For example, a polymer compound such as Teflon may be used to form the electrode.

The electrode and the separator are immersed in an electrolytic solution,
Electrodes are placed opposite to each other through the separator to form the element of the present invention. This separator is commonly used in ordinary electric double layer capacitors. For example, glass non-woven fabric, polypropylene non-woven fabric, cellulose paper and the like are preferable.

The device of the present invention is housed in a can formed of a positive electrode can and a negative electrode can such as stainless steel via an insulating packing. The packing described above may be any of widely used polypropylene, polyethylene, polypropylene hot-melt films, and the like. A metal can is sealed using this insulating packing.

When the above-mentioned electrode is housed in the metal can, it is important to electrically connect the electrode and the metal can, that is, to collect electricity. This current collecting method is, for example, a method of bonding an electrode and a metal can with a conductive adhesive such as carbon paste, or a method of collecting metal by coating a metal such as aluminum, gold, platinum, or titanium on the electrode, or There is a method of collecting current with a metal mesh or the like embedded in the electrode in advance.

[0012]

EFFECT OF THE INVENTION By using an organic solvent solution of a tetraalkylammonium salt in which any one of the alkyl groups according to the present invention is a methyl group as an electrolytic solution, an organic electrolyte battery having special high temperature storage characteristics can be obtained. It was The present invention will be specifically described below with reference to examples.

[0013]

【Example】

[Method of manufacturing electrode] Water-soluble resol (about 60% concentration) /
An aqueous solution prepared by mixing zinc chloride / water at a weight ratio of 10/25/4 was formed on a glass plate with a film applicator. Next, a glass plate was covered on the formed aqueous solution and heated at a temperature of about 100 ° C. for 1 hour so as to prevent water from evaporating, and cured to obtain a film-like phenol resin cured porous body having a thickness of about 200 μm.

The phenol resin-cured porous body was placed in a siliconite electric furnace, heated in a nitrogen stream at a rate of 40 ° C./hour and heat-treated to 500 ° C. to form a film of an organic semiconductor having a polyacene skeleton structure. A porous body was obtained. When the electric conductivity of the porous body was measured by the DC 4-terminal method, it was 1
It was 0 ⁻⁴ (Ωcm) ⁻¹ . The apparent density is 0.35
It was g / cm ³ , and the film was excellent in mechanical strength. H / C obtained by elemental analysis was 0.27,
The specific surface area by the BET method was 2,100 m ² / g.

The above organic semiconductor was crushed for 3 hours using a ball mill to obtain PAS powder. Teflon powder was added to this powder at 10% by weight of PAS powder, and carbon black was added at 5%.
% To obtain a disk-shaped molded product having a thickness of 200 μm and a diameter of 4 mm.

[Battery Manufacturing Method] JIS Standard SUS30
A plate made of four materials and having a thickness of 150 μm is press-processed, as shown in FIG.
The negative electrode can shown in was obtained. Similarly, a 200 μm-thick plate made of SUS304 material was pressed to obtain the positive electrode can shown in FIG.

The electrodes obtained by the above-mentioned method were adhered to a negative electrode can and one to a positive electrode can by using a conductive adhesive in which carbon powder was dispersed in a phenolic resin. These were dried with a vacuum dryer at a temperature of 200 ° C. for 12 hours and then impregnated with an electrolytic solution in a dry box. A 1 mol / l solution of CH ₃ (C ₂ H ₅ ) ₃ NBF ₄ -propylene carbonate was used as the electrolytic solution. The electrode adhered to the can was immersed in this solution to impregnate the electrode with the electrolytic solution. A separator made of a glass non-woven fabric was impregnated with an electrolytic solution by the same method, and the electrode impregnated with the electrolytic solution was placed opposite to the separator to assemble the element of the present invention.

Using a pre-processed polypropylene packing and the above-described negative electrode can and positive electrode can, the above-mentioned device was housed and then caulked and sealed with a pressing machine. The obtained organic electrolyte battery had an outer diameter of 6.8 mm and a thickness of 1.0 mm. This is shown in FIG. In the figure, (2) is a negative electrode metal can, (3) is a negative electrode, (4) is a separator,
(5) is a positive electrode, (6) is a polypropylene packing,
(1) is a positive electrode metal can.

The above-mentioned condenser is set to 1 kHz-1 mA.
The internal resistance was 23Ω when measured with an alternating current of. Further, this capacitor was subjected to an acceleration test in a 2.50 V, 70 ° C. constant temperature bath. The internal resistance after 40 hours is 40
Ω.

[0020]

[Comparative Example] 1.0 mol / l (C ₂
A battery was assembled and the high temperature storage characteristics were measured in the same manner as in the example except that H ₅ ) ₄ NBF ₄ -propylene carbonate was used. The initial internal resistance was 24Ω, but the internal resistance after the acceleration test was 105Ω, which was four times or more that of the initial value. It can be seen that the use of CH ₃ (C ₂ H ₅ ) ₃ NBF ₄ as the electrolyte significantly improved the high temperature storage characteristics.

[0021]

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a negative electrode metal can of the present invention.

FIG. 2 is a sectional view of the positive electrode metal can of the present invention.

FIG. 3 is a sectional view showing an example of a capacitor of the present invention.

[Explanation of symbols]

 1 Positive Metal Can 2 Negative Metal Can 3 Negative Electrode 4 Separator 5 Positive Electrode 6 Insulating Packing

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Hisashi Satake 1-2-6-303, Tomobuchi-cho, Miyakojima-ku, Osaka-shi, Osaka (72) Inventor Eiichi Kubota 1-7-16 Akagawa, Asahi-ku, Osaka-shi, Osakaー No. 706 (72) Eiji Okamoto, Eiji Okamoto 47, Saga Nakadori-cho, Ukyo-ku, Kyoto 11 (72) Inventor Shizukuni Yada 2-6-13 Miyanishi, Harima-cho, Kako-gun, Hyogo

Claims (1)

[Claims] 1. A coin-type organic electrolyte battery comprising a positive electrode can, a positive electrode and a negative electrode made of an organic semiconductor containing a polyacene-based skeleton structure, a separator, a negative electrode can, and an organic electrolyte. An organic electrolyte battery, wherein the organic electrolytic solution is a solution of a tetraalkylammonium salt represented by the following formula in an organic solvent. Embedded image (However, in the formula, R ₁ , R ₂ , R ₃ and R ₄ represent an alkyl group, any one of which is a methyl group and the remaining three are an ethyl group. X is an anion residue of a tetraalkylammonium salt. Represents a group.)