JP3031037B2 - Manufacturing method of zinc alkaline battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mercury-free zinc-alkaline battery technology using zinc as a negative electrode active material, an aqueous alkaline solution as an electrolyte, and manganese dioxide, silver oxide, oxygen and the like as a positive electrode active material. Another object of the present invention is to provide a method for producing a zinc alkaline battery which is excellent in storability and discharge performance.

[0002]

2. Description of the Related Art For about ten years, there has been a strong concern that environmental pollution due to mercury in waste batteries has been seriously studied, and studies have been made on reducing 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 based on the battery weight at present. However, today, there is a concern about environmental destruction caused by industrial products worldwide, as represented by the problem of depletion of the ozone layer by freon and the like, and there is an increasing demand to completely eliminate mercury in alkaline dry batteries. The approach to the mercury-free alkaline battery technology was made at the time when alkaline batteries with mercury were developed, and patents and reports include zinc alloys, inorganic inhibitors,
Many applications and publications have been made regarding organic inhibitors.

[0003] For example, a method of using as an alloy addition element (Japanese Patent Publication No. 41576/1994), a method of using indium oxide and indium hydroxide as an inorganic inhibitor (Japanese Patent Publication No. 51-36450, Japanese Patent Application Laid-Open No. 49-93831,
JP-A-49-112125, Proceedings of the 56th Electrification Congress; Publication No. 3G05; p. 205), a method of adding indium oxide and cadmium oxide (JP-A-1-105)
466). Examples of addition as an additive to a negative electrode of a secondary battery (JP-A-61-96666, JP-A-6-96666)
1-101955).

Further, as organic inhibitors, amines, diethanolamine, oleic acid, lauryl ether or ethylene oxide polymers have been proposed. As an example of composite addition of an inorganic inhibitor and an organic inhibitor, it has been proposed to compositely add indium hydroxide and an ethoxyl fluoroalcohol-based polyfluorinated compound (Japanese Patent Laid-Open No. 2-79367).

[0005]

In a battery in which pure zinc is used as the active material of the negative electrode in the form of mercury-free silver, a corrosion reaction accompanying the generation of hydrogen of zinc occurs violently, and the internal pressure of the battery increases, and the electrolytic solution is discharged to the outside. There is a problem that extrusion and leakage resistance decrease.

Further, in a partially discharged battery, the hydrogen gas generation rate of the zinc negative electrode is accelerated, and the leakage resistance is further reduced. These are caused by the fact that mercury, which suppressed the corrosion reaction by increasing the hydrogen overvoltage on the zinc surface, disappeared.

[0007] Even if a corrosion-resistant zinc alloy containing indium, aluminum, and lead is proven to be effective in reducing the mercury of a zinc negative electrode, if the battery is made of mercury-free, the leakage resistance of the battery after partial discharge is ensured. Can not.

Also, a battery formed by adding pure 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 a battery formed only of the above-mentioned corrosion-resistant alloy. Liquid leakage resistance cannot be secured.

Further, even when a battery is formed by adding an amine surfactant which is 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, the liquid leakage resistance is improved. Cannot be secured.

[0010] Further, even in a battery composed of a gel negative electrode using pure zinc powder as a negative electrode active material and an ethoxyl fluoroalcohol-based polyfluoride compound added thereto, liquid leakage resistance after partial discharge cannot be ensured.

[0011] As described above, the conventional seeds are not completely effective in inhibiting corrosion, and are not practical at least for sealed batteries.

In order to realize the realization of mercury-free alkaline batteries, the present inventors have developed a material and a material which can exhibit the highest effects in the composite of a corrosion-resistant zinc alloy, an inorganic inhibitor, an aromatic amine, and an organic inhibitor. The optimum condition and concentration were examined.

[0013]

SUMMARY OF THE INVENTION In order to solve these problems, the present invention is to use a combination 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,
Bismuth, calcium, aluminum, and lithium are added in a proper combination containing at least one or more of a corrosion-resistant zinc alloy powder added in a proper amount and an appropriate concentration of, for example, sulfanilic acid as an aromatic amine, as an inorganic inhibitor. It is composed of a gel alkaline electrolyte in which an oxide of yttrium or gallium or a hydrate thereof is dispersed at an appropriate concentration, and a surfactant having an appropriate property as an organic inhibitor is added in an appropriate amount.

The sulfanilic acid is contained in an amount of 0.01 to 0.1% by weight based on the zinc alloy powder, and the oxide or hydrate of yttrium or gallium, which is also an inorganic inhibitor, is added to the zinc alloy powder in an amount of 0.01 to 0.1% by weight. ~ 0.
The effect can be obtained when the content is 1 wt%, but the most effective effect is obtained when the fluorine-based surfactant is further contained as an organic inhibitor in an amount of 0.001 to 0.1 wt% based on the zinc alloy powder.

[0016]

The corrosion-resistant zinc alloy, the aromatic amine, the inorganic inhibitor, the organic inhibitor material of the present invention, and the combination and composition in the composite thereof have been found as a result of intensive research so that each of them can exert the composite effect to the maximum. It is. The elucidation of its action and effect is unclear at present, but is presumed as follows.

First, the functions and effects of the additive elements of the alloy, the aromatic amine, the inorganic inhibitor and the organic inhibitor alone are as follows. Among the additional elements in the alloy, indium, lead, and bismuth have a high hydrogen overpotential of these elements themselves, and are added to zinc to act to increase the hydrogen overpotential on the surface. If these are uniformly added to the alloy, the added element exists at every depth of the powder,
This effect is maintained even if a new zinc surface appears due to the discharge. Further, aluminum, calcium and lithium have the effect of spheroidizing zinc particles, and reduce the amount of corrosion per unit weight of zinc powder to reduce the true specific surface area.

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 alienated. In particular, after overdischarge where the discharge progressed deeply,
The coexistence of zinc and zinc oxide further 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 during overdischarge is exhibited.

Yttrium as an inorganic inhibitor;
When gallium oxide or its hydrate is dispersed as a powder in a gel alkaline electrolyte in the coexistence state with a zinc alloy, a part of it is ionized and positively adsorbed on the zinc surface, and a hydrogen generating cathode is formed. 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 fluorine-based surfactant as an organic inhibitor coexists with a zinc alloy in a gelled alkaline electrolyte, it chemically adsorbs on the zinc alloy surface on the principle of metallic soap to form a hydrophobic monolayer, Shows anticorrosion effect.

Next, the composite effect of the zinc alloy, the sulfanilic acid, the oxide of yttrium or gallium or the hydrate thereof will be described. Since sulfanilic acid, yttrium, or gallium adsorbs and acts on the surface of the zinc alloy, the adsorption process needs to occur smoothly and uniformly. Since significant hydrogen gas is generated on the surface of the zinc alloy having no corrosion resistance, the adsorption of the sulfanilic acid, yttrium or gallium is alienated, and the adsorption state becomes uneven. However, the generation of hydrogen gas is suppressed on the surface of the zinc alloy having good corrosion resistance, and the adsorption takes place smoothly and uniformly, so that a combined effect can be obtained. This is the same even after partial discharge or overdischarge.

Next, the combined effect of a zinc alloy, an oxide of sulfanilic acid, yttrium or gallium or a hydrate thereof and a fluorine-based surfactant will be described.

The mechanism of action of sulfanilic acid, yttrium or gallium is as described above, but if all are adsorbed in the initial stage, the number of elements that act after partial discharge or after overdischarge will decrease. It is considered that the surfactant, in addition to its own anticorrosive action, suppresses excessive adsorption of sulfanilic acid, yttrium or gallium, acts after partial discharge or overdischarge, and acts to secure 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 of comparative evaluation of the liquid leakage resistance will be described in order to show the effects of the method for producing a corrosion resistant zinc alloy and the production method of the present invention.

The corrosion-resistant zinc alloy powder has a purity of 99.97%
Was prepared by a so-called atomizing method in which zinc was melted and sprayed with compressed air to obtain a powder, and this was classified with a sieve to adjust the particle size to 45 to 150 mesh. The gelled negative electrode was prepared as follows. First, 3% by weight of sodium acrylate and 1% by weight of carboxymethylcellulose are added to a 40% by weight potassium hydroxide solution (containing 3% by weight of ZnO) to gel. Next, a predetermined amount of a surfactant is charged and stirred while stirring the gel electrolyte, followed by aging for 2 to 3 hours. Next, zinc alloy powder was added in a weight ratio twice that of the gel electrolyte and mixed. FIG. 1 is a structural cross-sectional view of the 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 current collector of the gelled negative electrode. 5 is a positive electrode terminal cap, 6 is a metal case, 7
Denotes a battery outer can, 8 denotes a polyethylene resin sealing member for closing the opening of the case 6, and 9 denotes a bottom plate forming a negative electrode terminal.

The comparative evaluation method of the leak resistance is as follows: 100 alkaline manganese batteries shown in FIG. 1 were trial-produced at a constant current of 1 A, which is the most severe condition for LR6, to a depth of 20% of the theoretical capacity. The battery was discharged, then stored at 60 ° C. for a certain period, and the number of leaked batteries was evaluated as the number of leaked batteries. Under these severe conditions, if the number of leaked liquids after storage at 60 ° C. for 30 days is 0, it can be used practically. However, it is preferable that the performance related to reliability such as leak resistance can be maintained as long as possible. Further, as one index indicating the leak resistance, the generation rate of hydrogen gas generated from the battery was measured. The effect of various inhibitors when the alloy alone was taken as 100 was evaluated.

Here, the zinc alloy was examined in advance by changing the composition of various additional elements in various ways. As a result, indium or another group of lead, bismuth, calcium, aluminum and lithium was used alone or in combination. It has been found that the contained zinc alloy powder is good. The best alloy compositions among them are shown in (Table 1).

[0029]

[Table 1]

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

[0031]

[Table 2]

(Table 2) Even with a zinc alloy having better corrosion resistance, practical corrosion resistance cannot be secured by itself. Further, even if sulfanilic acid is added to pure zinc, corrosion resistance cannot be ensured. However, a certain amount of corrosion resistance can be obtained by adding an appropriate amount of sulfanilic acid of 0.01 to 0.1 wt% to a zinc alloy having excellent corrosion resistance.

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

[0034]

[Table 3]

As shown in Table 3, even if sulfanilic acid and yttrium compound are added to pure zinc, corrosion resistance cannot be ensured. Practical corrosion resistance can be ensured by adding a zinc alloy and sulfanilic acid having excellent corrosion resistance, 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 results can be obtained without using a 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 a zinc alloy and sulfanilic acid at 0.1 wt%. Table 4 shows the results of a liquid leakage test and an index of gas generation rate after storage at 60 ° C. for 30 days for batteries prepared by varying the amount of addition.

[0037]

[Table 4]

As shown in Table 4, even if sulfanilic acid and a gallium compound are added to pure zinc, corrosion resistance cannot be ensured. Practical corrosion resistance can be ensured by adding 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 gallium oxide hydrate of 0.01 to 0.1 wt%. Note that almost the same results can be obtained without using a hydrate.

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

[0040]

[Table 5]

According to Table 5, even if sulfanilic acid, a gallium compound, and a fluorine-based surfactant are combined with pure zinc, corrosion resistance cannot be ensured. Practical corrosion resistance can be ensured by adding an appropriate amount of 0.1 wt% of sulfanilic acid and an appropriate amount of 0.1 wt% of gallium oxide hydrate to a zinc alloy with excellent corrosion resistance, and furthermore, a fluorine-based surfactant as an organic inhibitor. 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 can be added to a gelled alkaline electrolyte to obtain a negative electrode formulation which can withstand practical use. However, by adding an appropriate amount of yttrium or gallium oxide or a hydrate thereof, and further adding an appropriate amount of a fluorine-based surfactant, an unexpected combined effect of further reducing the gas generation rate was obtained, and It is possible to provide a pollution-free zinc-alkali battery having good properties.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an alkaline manganese battery according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positive electrode mixture 2 Gelled negative electrode 3 Separator

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Sachiko Sugihara 1006 Kazuma Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (56) References JP-A-2-267856 (JP, A) JP-A-4- 26067 (JP, A) JP-A-63-271863 (JP, A) JP-B-55-9150 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 6/00-6 / 22 H01M 4/36-4/62

Claims (6)

(57) [Claims] In the preparation of a gelled negative electrode in which zinc alloy powder is mixed and dispersed in a gelled alkaline electrolyte, indium,
A zinc alloy containing at least one of the group consisting of lead, bismuth, calcium, aluminum and lithium and containing no mercury is used as an active material, and sulfanilic acid is used as an aromatic amine in the alkaline electrolyte.
A method for producing a zinc-alkaline battery , comprising 0.01 to 0.1 wt% based on powder . 2. A method for preparing a gelled negative electrode in which a zinc alloy powder is mixed and dispersed in a gelled alkaline electrolyte, wherein indium,
A zinc alloy containing at least one of the group consisting of lead, bismuth, calcium, aluminum and lithium and containing no mercury as an active material, and sulfanilic acid as an aromatic amine in the alkaline electrolyte solution.
A method for producing a zinc-alkaline battery , comprising 0.01 to 0.1% by weight of an oxide of any one of yttrium and gallium and a hydrate thereof. 3. Lee Ttoriumu, any one of an oxide or a hydrate of gallium, according to claim 2, wherein the inclusion 0.01 to 0.1% with respect to the zinc alloy powder Manufacturing method of zinc alkaline battery. 4. A method for preparing a gelled negative electrode in which a zinc alloy powder is mixed and dispersed in a gelled alkaline electrolyte, wherein indium,
A zinc alloy containing at least one of the group consisting of lead, bismuth, calcium, aluminum and lithium and containing no mercury as an active material, and sulfanilic acid as an aromatic amine in the alkaline electrolyte solution.
0.01 to 0.1% and, yttrium, oxides of any one of gallium or by incorporating a hydrate thereof, zinc alkali, characterized in that it further comprises a fluorosurfactant against Battery manufacturing method. 5. yttrium, any one of an oxide or a hydrate of gallium, zinc according to claim 4, characterized in that to contain 0.01 to 0.1% with respect to the zinc alloy powder Manufacturing method of alkaline battery. 6. Fluorine-based surfactant, the preparation of zinc alkaline battery according to claim 4, wherein be contained 0.001 to 0.1% with respect to the zinc alloy powder.