JPH05242895A - Manufacture of zinc alkaline battery - Google Patents

Abstract

PURPOSE:To provide a battery capable of the practical use by compounding an excellent anticorrosive zinc alloy and sulfanilic acid, an oxide of yttrium or gallium and or its hydrate, further a fluorine surface-active agent in demercuration of an alkaline-manganese dioxide battery. CONSTITUTION:In a gele alkaline electrolytic solution, zinc alloy powder containing at least one or more of indium, lead, bismuth, calcium, aluminum, and lithium is used as an active material. A gele negative electrode 2 is used where this electrolytic solution is made to contain sulfanilic acid 0.01 to 0.1wt.%, an oxide of yttrium or gallium, or its hydrate 0.01 to 0.1wt.%, further a fluorine surface active agent 0.001 to 0.1wt.% as an organic inhibitor are compositely contained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for producing anhydrous silver in a zinc-alkali battery using zinc as a negative electrode active material, an alkaline aqueous solution as an electrolyte, and manganese dioxide, silver oxide, oxygen, etc. as a positive electrode active material, and is pollution-free. And a method for producing a zinc-alkaline battery having excellent storability and discharge performance.

[0002]

2. Description of the Related Art Since about 10 years ago, there has been a strong concern about environmental pollution due to mercury in waste batteries, and studies have been made to reduce the amount of mercury in alkaline dry batteries. As a result, due to the development of corrosion resistant zinc alloys and the like, the amount of mercury contained in alkaline dry batteries has been reduced to 250 ppm with respect to the battery weight at present. However, as represented by the problem of ozone layer depletion due to CFCs and the like, there is a growing concern over environmental destruction problems caused by industrial products worldwide, and there is a growing demand for complete elimination of mercury in alkaline batteries. The approach to the mercury-free technology for alkaline dry batteries was made from the time when mercury-added alkaline dry batteries were being developed, and patents and reports mentioned zinc alloys, inorganic inhibitors,
Many applications and announcements have been made regarding organic inhibitors.

For example, a method of using as an alloying additive element (Japanese Patent Publication No. 1-45766), a method of using indium oxide and indium hydroxide as an inorganic inhibitor (Japanese Patent Publication No. 51-36450, Japanese Patent Publication No. 49-93831,).
JP-A-49-112125, Proceedings of the 56th electrification conference, presentation number 3G05; page 205), a method of adding indium oxide and cadmium oxide (JP-A-1-105)
466) and so on. In addition, examples of addition as an additive to the negative electrode of a secondary battery (JP-A-61-96666, JP-A-SHO-6)
1-101955).

As the organic inhibitor, amine, diethanolamine, oleic acid, lauryl ether or ethylene oxide polymer has been proposed. As an example of the combined addition of an inorganic inhibitor and an organic inhibitor, it has been proposed to add indium hydroxide and an ethoxylfluoroalcohol-based polyfluorinated compound in combination (JP-A-2-79367).

[0005]

In a battery using pure zinc as the negative electrode active material as it is as anhydrous silver, the corrosion reaction accompanied by hydrogen evolution of zinc occurs violently, and the internal pressure of the battery increases, so that the electrolytic solution is discharged to the outside. There is a problem of extrusion and deterioration of liquid leakage resistance.

Further, in a partially discharged battery, the hydrogen gas generation rate of the zinc negative electrode is accelerated, and the leakage resistance property is further deteriorated. These are due to the disappearance of the mercury that suppressed the corrosion reaction by increasing the hydrogen overvoltage on the zinc surface.

[0007] Even if a corrosion-resistant zinc alloy containing indium, aluminum, and lead, which has been proved to have a corrosion resistance effect by reducing mercury in the zinc negative electrode, is constructed as a battery with no-silver-free battery, the leakage resistance of the battery after partial discharge is secured. Can not.

[0008] Further, a battery constructed by adding commercially available indium oxide or indium hydroxide to a gel negative electrode using pure zinc powder as an active material of the negative electrode is practically the same as the battery constructed only by the above corrosion resistant alloy. The leak resistance cannot be secured.

Further, even if a battery is constructed by adding an amine-based surfactant effective as an organic inhibitor to a gel negative electrode using a corrosion-resistant zinc alloy containing indium, aluminum and lead as an active material of the negative electrode, liquid leakage resistance is obtained. Cannot be secured.

Further, even in a battery constructed by adding a complex fluorinated ethoxylfluoroalcohol compound to a gel negative electrode using pure zinc powder as the negative electrode active material, the liquid leakage resistance after partial discharge cannot be ensured.

As described above, the conventional seeds are not completely effective in suppressing corrosion, and are not practical at least for sealed batteries.

In order to make it possible to realize the silver-free conversion of alkaline dry batteries, the inventors of the present invention have developed a material and a material which can exert the maximum effect in the combination of a corrosion-resistant zinc alloy, an inorganic inhibitor, an aromatic amine, and an organic inhibitor. The optimum state and concentration were examined.

[0013]

In order to solve these problems, the present invention intends to carry out the combined use of a corrosion resistant zinc alloy, an inorganic inhibitor, an aromatic amine, and an organic inhibitor. The configuration of the present invention will be described.

The gelled negative electrode of the present invention comprises indium, lead,
Corrosion-resistant zinc alloy powder containing at least one of bismuth, calcium, aluminum, and lithium in a proper combination and a proper amount of aromatic amine such as sulfanilic acid is added as an inorganic inhibitor. It is composed of a gelled alkaline electrolyte in which an oxide of yttrium or gallium or a hydrate thereof is dispersed at an appropriate concentration, and an appropriate amount of a surfactant having an appropriate property as an organic inhibitor is added.

The above-mentioned sulfanilic acid is contained in an amount of 0.01 to 0.1 wt% with respect to the zinc alloy powder, and yttrium or gallium oxide, which is also an inorganic inhibitor, or its hydrate is contained in an amount of 0.01 to 0.1 with respect to the zinc alloy powder. ~ 0.
The effect is obtained when the content is 1 wt%, but the effect is most effective when the fluorine-based surfactant as an organic inhibitor is contained in an amount of 0.001 to 0.1 wt% with respect to the zinc alloy powder.

[0016]

[Function] Regarding the combination and composition of the corrosion-resistant zinc alloy, aromatic amine, inorganic inhibitor, organic inhibitor material of the present invention, and their combination, they have been found as a result of intensive research so as to maximize their combined effect. Is. The elucidation of its action and effect is unclear at present, but it is presumed as follows.

First, the action and effect of each of the additive element of the alloy, the aromatic amine, the inorganic inhibitor, and the organic inhibitor alone is as follows. Among the additional elements in the alloy, indium, lead and bismuth have a high hydrogen overvoltage of those elements themselves, and are added to zinc, and have the action of increasing the hydrogen overvoltage of the surface. If these are uniformly added to the alloy, the additive element exists at any depth of the powder,
This effect is retained even if a new zinc surface appears due to discharge. Further, aluminum, calcium, and lithium have the effect of making the zinc particles spherical, and reduce the true specific surface area, thus reducing the amount of corrosion per unit weight of the zinc powder.

When the aromatic amine is dispersed in the gelled alkaline electrolyte in the coexistence state with the zinc alloy, the ion adsorption action by the amine group is promoted and the cathode reaction of hydrogen generation is excluded. In particular, after over-discharging where the discharge deeply progresses,
The coexistence of zinc and zinc oxide increases the gas generation rate, but when sulfanilic acid is added as an aromatic amine, the adsorptivity to zinc oxide is further increased, and the anticorrosion effect at the time of overdischarge is exhibited.

Yttrium as an inorganic inhibitor,
When gallium oxide or its hydrate is dispersed as a powder in a gelled alkaline electrolyte in the coexistence state with a zinc alloy, a part of it is ionized and adsorbed onto the zinc surface as positive ions, generating a hydrogen-generating cathode. It has the function of alienating the reaction.
The remaining part remains in the electrolytic solution, and even if a new surface appears due to discharge, it is adsorbed on the surface and exerts its effect.

When a fluorosurfactant as an organic inhibitor coexists with a zinc alloy in a gelled alkaline electrolyte, it chemically adsorbs on the surface of the zinc alloy by the principle of metallic soap to form a hydrophobic monomolecular layer, Shows anticorrosion effect.

Next, the combined effect of a zinc alloy, sulfanilic acid, and an oxide of yttrium or gallium or a hydrate thereof will be described. Since sulfanilic acid, yttrium, or gallium act by being adsorbed on the surface of the zinc alloy, the adsorption process needs to occur smoothly and uniformly. Since hydrogen gas is remarkably generated on the surface of a zinc alloy having no corrosion resistance, the adsorption of sulfanilic acid, yttrium or gallium is alienated and the adsorption state becomes non-uniform. However, hydrogen gas generation is suppressed on the surface of a zinc alloy having good corrosion resistance, and adsorption is smoothly and uniformly achieved, so that a composite effect is obtained. This also applies to the state after partial discharge or after overdischarge.

Next, the combined effect of the zinc alloy, the sulfanilic acid, the oxide of yttrium or gallium or its hydrate, and the fluorine-containing surfactant will be described.

The mechanism of action of sulfanilic acid, yttrium or gallium is as described above, but if all are adsorbed at the initial stage, the number of substances acting after partial discharge or over discharge will be reduced. In addition to its anticorrosion effect, the surfactant is considered to suppress excessive adsorption of sulfanilic acid, yttrium, or gallium, act after partial discharge or overdischarge, and ensure the function of securing these materials.

[0024]

The details and effects of the present invention will be described below with reference to examples.

First, the structure of the LR6 type alkaline manganese battery used in the examples and the method for comparative evaluation of the leakage resistance will be described in order to show the method of producing the corrosion resistant zinc alloy and the effect of the manufacturing method of the present invention.

The corrosion resistant zinc alloy powder has a purity of 99.97%.
It was prepared by a so-called atomization method, in which zinc was melted and sprayed with compressed air to be pulverized, and this was classified by a sieve to adjust the particle size range to 45 to 150 mesh. The gelled negative electrode was prepared as follows. First, 3 wt% sodium acrylate and 1 wt% carboxymethylcellulose are added to a 40 wt% potassium hydroxide solution (containing 3 wt% ZnO) for gelation. Then, a predetermined amount of a surfactant is added while stirring the gel electrolyte, and the mixture is stirred and aged for 2 to 3 hours. Next, the zinc alloy powder was added and mixed in a weight ratio twice that of the gel electrolyte. FIG. 1 is a structural cross-sectional view of an alkaline manganese battery LR6 used in this example. In FIG. 1, 1 is a positive electrode mixture, 2 is a gelled negative electrode characterized by the present invention, 3 is a separator, and 4 is a gelled negative electrode current collector. 5 is a positive electrode terminal cap, 6 is a metal case, 7
Is a battery outer can, 8 is a polyethylene resin sealing body that closes the opening of the case 6, and 9 is a bottom plate that serves as a negative electrode terminal.

The comparative evaluation method of liquid leakage resistance was carried out by making 100 prototypes of the alkaline manganese battery shown in FIG. 1 and making a partial depth up to 20% of the theoretical capacity at a constant current of 1 A, which is the most severe condition for LR6. After discharging, the battery was stored at 60 ° C. for a certain period of time and the number of leaked batteries was evaluated as the number of leaked liquids. Under such harsh conditions, if the number of leaked liquids is 0 after 30 days of storage at 60 ° C., it is practical, but it is preferable that the performance related to reliability such as leak resistance can be maintained as long as possible. In addition, the rate of generation of hydrogen gas generated from the battery was measured as one index showing the leakage resistance. The effect of various inhibitors when the alloy alone was set to 100 was evaluated.

Here, the zinc alloy was studied in advance by variously changing the composition of various additive elements, and as a result, indium and other lead, bismuth, calcium, aluminum, and lithium were used alone or in combination. It has been found that the zinc alloy powder contained is good. The best alloy composition among them is shown in (Table 1).

[0029]

[Table 1]

(Example 1) The appropriate addition amounts of zinc alloy and sulfanilic acid will be described. Table 2 shows the results of the liquid leakage test and the index of the gas generation rate after storage at 60 ° C. for 30 days in batteries prepared by changing the addition amount in various ways.

[0031]

[Table 2]

Even in the case of a zinc alloy having excellent corrosion resistance as shown in Table 2, practical corrosion resistance cannot be ensured by itself. Further, even if sulfanilic acid is added to pure zinc, the corrosion resistance cannot be secured. However, corrosion resistance can be obtained to some extent by adding an appropriate amount of 0.01 to 0.1 wt% of sulfanilic acid to a zinc alloy having excellent corrosion resistance.

(Example 2) An appropriate addition amount of 0.1 wt% of zinc alloy and sulfanilic acid was fixed, and an appropriate addition amount of yttrium oxide hydrate as an inorganic inhibitor will be described. Table 3 shows the results of the liquid leakage test and the index of the gas generation rate after storage at 60 ° C. for 30 days in batteries prepared by changing the addition amount in various ways.

[0034]

[Table 3]

From Table 3, it is impossible to ensure corrosion resistance even if sulfanilic acid and an yttrium compound are added to pure zinc. Practical corrosion resistance can be secured by the addition of a zinc alloy having excellent corrosion resistance and sulfanilic acid, and the gas generation rate index can be suppressed to some extent by adding an appropriate amount of yttrium oxide hydrate of 0.01 to 0.1 wt%. Note that almost the same result can be obtained without using the hydrate.

(Example 3) An appropriate addition amount of gallium oxide hydrate as an inorganic inhibitor will be described while fixing an appropriate addition amount of zinc alloy and sulfanilic acid of 0.1 wt%. Table 4 shows the results of the liquid leakage test and the indexes of the gas generation rate after storage at 60 ° C. for 30 days in the batteries prepared by changing the addition amount in various ways.

[0037]

[Table 4]

From Table 4, it is not possible to secure corrosion resistance even if sulfanilic acid and a gallium compound are added to pure zinc. Practical corrosion resistance can be secured by the addition of a zinc alloy having excellent corrosion resistance and sulfanilic acid, and the gas generation rate index can be suppressed to some extent by adding an appropriate amount of 0.01 to 0.1 wt% gallium oxide hydrate. Note that almost the same result can be obtained without using the hydrate.

(Example 4) When a zinc alloy and sulfanilic acid were fixed at 0.1 wt% and gallium oxide hydrate as an inorganic inhibitor was fixed at 0.1 wt%, an appropriate amount of an organic inhibitor, a fluorine-based surfactant, was added. explain. Table 5 shows the results of the liquid leakage test and the index of gas generation rate after storage at 60 ° C. for 30 days in batteries prepared by changing the addition amount in various ways.

[0040]

[Table 5]

From Table 5 above, even if pure zinc is combined with a sulfanilic acid, a gallium compound and a fluorine-containing surfactant, the corrosion resistance cannot be ensured. Practical corrosion resistance can be secured by adding 0.1 wt% of sulfanilic acid and 0.1 wt% of gallium oxide hydrate to zinc alloy with excellent corrosion resistance. By adding an appropriate amount of the agent in an amount of 0.001 to 0.1 wt%, the gas generation rate index is further reduced, and a negative electrode formulation that can withstand practical use is established.

[0042]

As described above, according to the present invention, in a zinc alkaline battery, a zinc alloy having a proper composition and a proper amount of sulfanilic acid are added to a gel alkaline electrolyte to obtain a negative electrode formulation which can be practically used. However, by adding an appropriate amount of yttrium or gallium oxide or its hydrate, and further adding an appropriate amount of a fluorine-based surfactant, the gas generation rate is further reduced. It is possible to provide a pollution-free zinc-alkaline battery having good properties.

[Brief description of drawings]

FIG. 1 is a sectional view of an alkaline manganese battery in an example of the present invention.

[Explanation of symbols]

 1 Positive Electrode Mixture 2 Gel Negative Electrode 3 Separator

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sachiko Sugihara 1006, Kadoma, Kadoma-shi, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (9)

[Claims] 1. In preparing a gelled negative electrode prepared by mixing and dispersing zinc alloy powder in a gelled alkaline electrolyte, indium,
A zinc alloy containing at least one selected from the group consisting of lead, bismuth, calcium, aluminum and lithium and containing no mercury is used as an active material, and an aromatic amine is contained in the alkaline electrolyte. Manufacturing method of zinc alkaline battery. 2. The aromatic amine is sulfanilic acid, which is 0.01 to 0.1 wt% with respect to the zinc alloy powder.
The method for producing a zinc alkaline battery according to claim 1, wherein the zinc alkaline battery is contained. 3. In the preparation of a gelled negative electrode obtained by mixing and dispersing zinc alloy powder in a gelled alkaline electrolyte, indium,
A zinc alloy containing at least one selected from the group consisting of lead, bismuth, calcium, aluminum and lithium and containing no mercury is used as an active material, an aromatic amine is contained in the alkaline electrolyte, and yttrium and gallium are further added. A method for producing a zinc alkaline battery, which comprises any one of the oxides or hydrates thereof. 4. The aromatic amine is sulfanilic acid, and is 0.01 to 0.1 wt% with respect to the zinc alloy powder.
The method for producing a zinc alkaline battery according to claim 3, wherein the zinc alkaline battery is contained. 5. One of the above yttrium and gallium.
The method for producing a zinc alkaline battery according to claim 3, wherein the seed oxide or its hydrate is contained in an amount of 0.01 to 0.1 wt% with respect to the zinc alloy powder. 6. A method for preparing a gelled negative electrode in which a zinc alloy powder is mixed and dispersed in a gelled alkaline electrolyte, indium,
A zinc alloy containing at least one selected from the group consisting of lead, bismuth, calcium, aluminum and lithium and containing no mercury is used as an active material, an aromatic amine is contained in the alkaline electrolyte, and yttrium and gallium A method for producing a zinc alkaline battery, which comprises containing any one kind of oxide or a hydrate thereof and further containing a fluorine-based surfactant. 7. The aromatic amine is sulfanilic acid, which is 0.01 to 0.1 wt% with respect to the zinc alloy powder.
The method for producing a zinc alkaline battery according to claim 6, wherein the zinc alkaline battery is contained. 8. One of the above yttrium and gallium.
The method for producing a zinc alkaline battery according to claim 6, wherein the seed oxide or its hydrate is contained in an amount of 0.01 to 0.1 wt% with respect to the zinc alloy powder. 9. The method for producing a zinc alkaline battery according to claim 6, wherein the fluorine-based surfactant is contained in an amount of 0.001 to 0.1 wt% with respect to the zinc alloy powder.