JPH0521056A - Manufacture of zinc alkaline battery - Google Patents

Abstract

PURPOSE:To provide a manufacture of a zinc alkaline battery which causes no environmental pollution and excellent in storage stability and discharge performance by applying a non-mercury technology of the zinc alkaline battery using zinc as its negative electrode active substance, using an alkaline solution as its electrolyte, using manganese dioxide, silver oxide, oxygen, etc., as its positive electrode active substance. CONSTITUTION:Upon adjustment of a gelled anode such that zinc alloy powders are mixed and dispersed in a gelled alkaline electrolyte, a zinc alloy containing at least one selected from the group consisting of In, Pb, Bi, Ca, or Al being used as its active substance. In the alkaline electrolyte, a poly-oxy-ethylenealkyl- phenyletheric surface active agent designated by the formula is contained ranging from 0.001 to 0.1wt.% relative to the zinc alloy. Or the surface active agent and an indium salt, as a starting substance, are contained ranging from 0.005 to 0.5wt.% relative to the zinc alloy. Whereby, the generation of hydrogen gas from the zinc anode can be suppressed, so that a zinc alkaline battery excellent in liquid-leakage resistance property can be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND 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 electrolytic solution, and manganese dioxide, silver oxide, oxygen, etc. as a positive electrode active material, and is pollution-free. In addition, the present invention provides a method for producing a zinc-alkaline battery that is excellent in storability and discharge performance.

[0002]

BACKGROUND OF THE INVENTION Since decades 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 batteries is currently about to be reduced to 250 ppm with respect to the battery weight.

However, as represented by the problem of ozone layer depletion due to CFCs, there is a growing concern over the environmental destruction of industrial products, and there is a growing demand for the complete elimination of mercury in alkaline batteries. There is.

[0004] The approach to the technology for producing anhydrous silver in alkaline batteries has been made since the time when the alkaline batteries containing mercury were developed. Applications and announcements have been made.

Indium is known as a material having a high hydrogen overvoltage, as an additive to the negative electrode of a secondary battery regardless of the primary battery. Many applications and presentations have been made on the method of using indium metal as an alloying additive element and the method of using an indium compound as an inorganic inhibitor.

For example, a method of using as an alloying additive element (Japanese Patent Publication No. 1-41576), a method of using indium oxide and indium hydroxide as an inorganic type inhibitor (Japanese Patent Publication No. 36450/51, Japanese Patent Publication No. 499381/31).
JP-A-49-112125, Proceedings of the 56th Electrification Congress: Presentation No. 3G05; page 205), a method of adding indium oxide and cadmium oxide in combination (JP-A-1-
105466) and the like. There is also an example of addition as an additive to the negative electrode of a secondary battery (JP-A 61-96666, JP-A 61-101955).

As the organic inhibitor, diethanolamine, oleic acid, lauryl ether, amine, or ethylene oxide polymer has been proposed. Further, 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).

[0008]

In a battery using pure zinc as an active material of a negative electrode as it is as anhydrous silver, a corrosive reaction accompanied by hydrogen generation 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 generation rate of the zinc negative electrode is accelerated, and the leakage resistance is further reduced.
These are due to the fact that by increasing the hydrogen overvoltage on the surface of zinc, the mercury that suppressed the corrosion reaction disappeared.

The corrosion resistance of zinc negative electrode has been proved to be low in mercury, and the corrosion resistance of zinc alloy containing indium, aluminum and lead has been proved. In addition, a battery made by adding commercially available indium oxide or indium hydroxide to a gel negative electrode using pure zinc powder as an active material for the negative electrode is practically used in the same manner as the battery made of only the above corrosion-resistant alloy. Leakage resistance of a typical battery cannot be secured.

A battery is constructed by adding an amine-based surfactant, which is effective in reducing mercury, to a gel negative electrode using a corrosion-resistant zinc alloy containing indium, aluminum and lead as an active material of the negative electrode. However, leakage resistance cannot be secured.

Furthermore, even in the case of a battery formed by adding a commercially available indium hydroxide and an ethoxylfluoroalcohol-based polyfluorinated compound to a gel negative electrode using pure zinc powder as an active material of the negative electrode, the leakage resistance of the battery after the partial discharge is prevented. Liquidity cannot be secured.

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

In realizing the silver-free alkaline dry battery, the inventors of the present invention have found that the best combination of corrosion-resistant zinc alloy, inorganic inhibitor and organic inhibitor, and the optimum material The state and concentration were examined.

[0015]

[Means for Solving the Problems] The gelled negative electrode in the battery of the present invention using a combination of a corrosion resistant zinc alloy, an inorganic inhibitor and an organic inhibitor is a proper combination of indium, lead, bismuth, calcium and aluminum. Corrosion resistant zinc alloy powder added in an amount and indium hydroxide powder with proper properties as an inorganic inhibitor were dispersed at a proper concentration, and a surfactant with a proper structural formula as an organic inhibitor was added in a proper amount. It is composed of a gelled alkaline electrolyte. Further, in order to effectively act the corrosion resistant zinc alloy, the inorganic inhibitor and the organic inhibitor, it is effective to add indium hydroxide after allowing the corrosion resistant zinc alloy and the surfactant to act. At the same time, indium hydroxide and a surfactant acting on the corrosion-resistant zinc alloy are not effective or have an adverse effect.

The above-mentioned surfactant is effective when contained in an alkaline electrolyte of 0.001 to 0.1 wt% with respect to the zinc alloy.

Further, the corrosion-resistant zinc alloy contains indium of 0.
Zinc alloy containing 0.001 to 1 wt% of 0.005 to 0.5 wt% of lead and bismuth in total or 0.01 to 1 wt% of indium and 1 or 2 of lead and bismuth. It is a zinc alloy containing 0.005 to 0.5 wt% in total and one or two kinds of calcium and aluminum in 0.005 to 0.2 wt% in total. Further, the appropriate addition amount of indium hydroxide is 0.005 to 0.5 wt% with respect to the zinc alloy.

Further, in view of the manufacturing method of the battery, it is preferable to use indium hydroxide synthesized from a starting material of indium chloride or indium sulfate and a neutralization treatment in an aqueous solution thereof. In the case of using indium chloride as the starting material and in the case of using indium sulfate, the former has better corrosion resistance. When indium nitrate and indium sulfate are used as starting materials, it is effective to use indium hydroxide synthesized by neutralization treatment from an aqueous solution containing chloride ions.

Further, it is effective that the above-mentioned indium hydroxide is composed of a powder containing 60 wt% or more, preferably 70 wt% or more of the total amount of particles having a particle diameter of 0.5 to 8 μm.

Further, indium hydroxide has a heat decomposition loss up to 900 ° C. of 18 to 30 wt%, preferably 20 to 2
A value of 5% is effective.

As the surfactant, those represented by (Chemical Formula 3) are effective.

[0022]

[Chemical 3]

[0023]

[Function] Regarding the corrosion-resistant zinc alloy of the present invention, the inorganic inhibitor material, the organic inhibitor material, and the combination and composition in the composite thereof, the results have been found as a result of intensive research so as to maximize the composite effect. Is. The elucidation of the mechanism of action is unclear at present, but it is speculated as follows.

First, the action and effect of the additive element of the alloy, the inorganic type inhibitor, and the organic type inhibitor alone are as follows.

Among the additional elements in the alloy, indium, lead and bismuth themselves have a high hydrogen overvoltage, and when added to zinc, they have the effect of increasing the hydrogen overvoltage on the surface. When these are uniformly added to the alloy, this effect is maintained even if a new zinc surface appears due to the discharge because the additive element exists at any depth of the powder. Also,
Aluminum and calcium 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 indium hydroxide is dispersed as a powder in a gelled alkaline electrolyte in the coexistence state with a zinc alloy,
Part of it is electrodeposited on the zinc alloy surface by the principle of displacement plating,
Increase the hydrogen overvoltage on the surface. The remaining portion remains as a solid in the electrolytic solution, and when a new zinc alloy surface appears due to discharge, it is electrodeposited on the new surface and exhibits an anticorrosion effect.

When the surfactant coexists with the zinc alloy in the gelled alkaline electrolyte, it chemically adsorbs on the surface of the zinc alloy to form a hydrophobic monolayer by the principle of metal soap, and exhibits a corrosion inhibiting effect.

Next, the combined effect of zinc alloy and indium hydroxide will be described. Since indium hydroxide acts by being electrodeposited on the surface of the zinc alloy, it is necessary that the electrodeposition occur smoothly and uniformly. Since a significant amount of hydrogen gas is generated on the surface of a zinc alloy having no corrosion resistance, the electrodeposition of indium is excluded and the electrodeposited state becomes non-uniform. However, generation of hydrogen gas is suppressed on the surface of the zinc alloy having good corrosion resistance, and the electrodeposition is smooth and uniform, so that a composite effect is obtained. This also applies to the state after partial discharge.

Next, the combined effect of the corrosion resistant zinc alloy, indium hydroxide and the surfactant will be described. The mechanism of action of indium hydroxide is as described above, but if all is electrodeposited, there will be nothing that acts after partial discharge. In addition to its anticorrosion effect, the surface active agent is thought to fulfill the function of suppressing the electrodeposition of indium more than necessary and securing the indium hydroxide that acts after partial discharge in which corrosion is promoted compared to that during non-discharge. In order to effectively perform such an action, it is effective to add indium hydroxide after the corrosion-resistant zinc alloy and the surfactant are allowed to act. At the same time, it is not effective to let indium hydroxide and the surfactant act on the corrosion resistant zinc alloy.

Next, the meaning of limiting the properties of indium hydroxide will be described. The smaller the particle size, the better the dispersibility in the gel electrolyte and the uniform effect can be exhibited in the gel negative electrode.

However, if it is too fine, it will dissolve at once, and it will not be possible to secure a sufficient amount to act after partial discharge. The limitation of the weight loss in the thermal decomposition is related to the crystallinity of indium hydroxide and affects the solubility of the particles. If the thermal decomposition loss is too small, the solubility will be low, and if it is too large, the solubility will be too high.

Next, the meaning of limiting the method for synthesizing indium hydroxide will be described. The properties of indium hydroxide differ depending on the synthesis method. In the synthesis using indium chloride and indium sulfate as the starting materials, the crystallinity and particle shape with excellent anticorrosive action are obtained as described above. In the case of using indium chloride as the starting material and in the case of using indium sulfate, the former is considerably better. Also, in the synthesis using indium nitrate and indium sulfate as starting materials,
When neutralization treatment is performed in an aqueous solution containing chloride ions, indium hydroxide having the same properties as the synthesis using indium chloride as a starting material can be synthesized.

Next, the meaning of limiting the molecular structure of the surfactant will be described. A surfactant having polyethylene oxide in the hydrophilic part has a high solubility as a micelle in an alkaline electrolyte, and when it is added to the electrolyte, it has a high anticorrosion effect because it migrates and adsorbs quickly to the zinc alloy surface. . When an alkyl group is held in the lipophilic part, when it is adsorbed on the surface of the zinc alloy, it has a high electric insulating property, so that electron transfer of the corrosion reaction is effectively excluded. If the bonding group between the hydrophilic part and the lipophilic part is a benzene ring, it exhibits strong alkali resistance and a stable anticorrosion effect.

[0034]

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

First, in order to show the effects of the method for producing a corrosion-resistant zinc alloy, the method for synthesizing indium hydroxide, and the production method of the present invention, a comparative evaluation of the structure of the LR6 type alkaline manganese battery used in Examples and the leakage resistance. The method will be described.

The corrosion resistant zinc alloy powder has a purity of 99.97%.
Of zinc is added, a predetermined amount of a predetermined additive element is added, and the mixture is uniformly dissolved, and then sprayed with compressed air to form a powder, which is prepared by a so-called atomization method, and is classified by a sieve to have a particle size range of 45 to 150. Adjusted to mesh.

For indium hydroxide, a predetermined amount of indium salt was added to ion-exchanged water in a saturated amount, and the solution was neutralized with ammonia gas as a neutralizing agent until the pH of the solution reached 9 while stirring the solution with a screw stirrer. . Then 0.5
By washing the filter with ion-exchanged water until the pH of the filtrate reaches 7.5 on a filter with a mesh size of μ, pulling a vacuum from under the filter to separate water, and vacuum drying at 60 ° C. Synthesized.

The gelled negative electrode was prepared as follows.
First, 40 wt% potassium hydroxide solution (3 wt% ZnO
%) And 3% by weight of sodium polyacrylate and 1% by weight of carboxymethyl cellulose are added to gel.
Then, a predetermined amount of a surfactant is added while stirring the gel electrolyte, and the mixture is aged for 2 to 3 hours. Next, a predetermined amount of indium hydroxide powder is gradually added and aged for 2 to 3 hours. Further, zinc alloy powder in a weight ratio twice that of the gel electrolyte was added and mixed.

FIG. 1 is a structural sectional view of an alkaline manganese battery LR6 used in this embodiment. 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 method of comparative evaluation of liquid leakage resistance was as follows: 100 alkaline manganese batteries shown in FIG.
The partial discharge was performed to a depth of 20% of the theoretical capacity at a constant current of 1 A, which is the most severe condition, and the number of leaked batteries after storage at 60 ° C. was evaluated as a leak index (%). Under this harsh condition, if the liquid leakage index is 0% after 30 days of storage at 60 ° C., it is practical, but it is desirable that the performance regarding reliability such as liquid leakage resistance can be maintained as long as possible.

Example 1 The present invention in the case of combining a zinc alloy, an inorganic inhibitor and an organic inhibitor will be described. First, in a zinc alloy, various additive elements were examined in advance with various compositions. As a result, indium is an essential alloying component, and lead and bismuth are added to each of these, or
Alternatively, a zinc alloy containing a complex or indium as an essential component, lead and bismuth respectively alone or in combination, and a zinc alloy system containing calcium and aluminum alone or in combination may be good alone. all right. The best alloy composition group among them is shown in (Table 1).

[0042]

[Table 1]

Table 2 shows the results of the liquid leakage test of the batteries prepared by changing the amount of the surfactant added to the various zinc alloys of the above (Table 1) after storage at 60 ° C. for 60 days.

Even with a zinc alloy having excellent corrosion resistance as shown in Table 2, it is not possible to secure very practical liquid leakage resistance by itself. However, it can be seen that the leakage resistance can be secured by adding an appropriate amount of the surfactant. The amount of the surfactant added to each zinc alloy is preferably in the range of 0.001 to 0.1 wt%.

[0045]

[Table 2]

In Table 3, the amount of indium hydroxide added to the various zinc alloys in Table 1 above was fixed at 0.01 wt% and the amount of indium hydroxide added was changed to 60%.
The results of the liquid leakage test after storage at 60 ° C for 60 days are shown.

Even with a zinc alloy having excellent corrosion resistance as shown in Table 3, it is not possible to secure very practical liquid leakage resistance by itself. However, it can be seen that the liquid leakage resistance can be secured by adding an appropriate amount of the surfactant and indium hydroxide. The amount of indium hydroxide added to each zinc alloy is 0.0
The range of 05 to 5 wt% is favorable.

In the case of pure zinc, practical leakage resistance cannot be ensured even if an appropriate amount of surfactant and indium hydroxide are added. Again, a composite with a suitable corrosion resistant zinc alloy is required.

[0049]

[Table 3]

Table 4 shows a battery prepared by fixing the addition amount of indium hydroxide to 0.1 wt% with respect to the various zinc alloys shown in Table 1 and changing the addition amount of the surfactant. 6
The leak test result after 60 days storage at 0 ° C is shown.

From Table 4, it is understood that the addition amount of the surfactant is preferably 0.001 to 0.1 wt% with respect to each zinc alloy. Here again, in the case of pure zinc, it is understood that practical leakage resistance cannot be ensured even if a surfactant and indium hydroxide are added in appropriate amounts.

[0052]

[Table 4]

In this example, indium hydroxide synthesized by neutralizing the aqueous solution of sulfate as a starting material was used, but indium hydroxide using a chloride or nitrate as a starting material may be used. The effect is obtained. The degree of the effect was higher in the order of the one using chloride as the starting material, the one using sulfide as the starting material, and the one using nitrate as the starting material.

The surfactant shown in (Chemical Formula 4) was used.

[0055]

[Chemical 4]

Example 2 The present invention is illustrated with respect to limiting starting materials in the synthesis of indium hydroxide.

In Table 5, the amount of the surfactant added to each zinc alloy was fixed at 0.1 wt% and the indium hydroxide having different starting materials was added at 0.1 wt% and stored at 60 ° C. for 75 days. The results of the subsequent liquid leakage test are shown.

From Table 5 it can be seen that even nitrates synthesized in the presence of chloride ions are suitable. By the way, even with nitrate as the starting material, the leak index is 60.
Although it is 0% at 60 ° C. on the 60th day, which is at a practical level, a battery using a chloride or a sulfate as a starting material can obtain reliability for further long-term leakage resistance.

[0059]

[Table 5]

Example 3 An example of limiting the particle size range of indium hydroxide will be described.

[Table 6] Table 6 shows 60% of the batteries in which 0.1 wt% of indium hydroxide having different particle size distribution was added to each zinc alloy.
The results of the liquid leakage test after 75 days at ° C are shown.

From Table 6, particles having a particle size in the range of 0.5 to 8 μm are contained in the amount of 60 wt% (residual particles remaining on the 0.5 μm coarse filter in the synthetic washing step are used. It is preferable to use indium hydroxide powder containing more than 8 μm) of particles), and at 70 wt% or more, liquid leakage may not occur until the 90th day at 60 ° C.

[0063]

[Table 6]

The indium hydroxide having a different particle size distribution used in this example was prepared by using a nitrate as a starting material and classifying a large particle size by a wet precipitation method.

Example 4 An example of limiting the thermal decomposition loss of indium hydroxide will be described.

In Table 7, indium hydroxide having different thermal decomposition weight loss up to 900 ° C. is added to each zinc alloy at 0.1 wt%.
The result of the liquid leakage test after storing the added battery for 75 days at 60 ° C is shown.

From Table 7, it is preferable to use indium hydroxide having a weight loss rate of 18 to 30 wt% due to thermal decomposition, and if it is 20 to 25%, it will not leak until 90 days at 60 ° C. There are cases.

[0068]

[Table 7]

The indium hydroxide having different thermal decomposition weight loss used in this example was prepared by using a chloride as a starting material, neutralizing the same, and changing the vacuum drying time after synthesis.

Example 5 The limitation of the composition of the corrosion resistant zinc alloy will be described. In Table 8, the addition amount of the organic inhibitor is fixed to the optimum 0.01 wt% and the addition amount of the indium hydroxide is fixed to the optimum 0.1 wt% for each zinc alloy. The results of the liquid leakage test after storage for 60 days at 60 ° C. of batteries prepared by changing the addition amount are shown.

From this, the amount of indium added to the zinc alloy is 0.01 to 1 wt%, lead and bismuth are each alone or 0.005 to 0.5 wt% in total, and calcium and aluminum are each alone or in combination. It is understood that 0.005 to 0.2 wt% is appropriate in total.

[0072]

[Table 8]

By the way, although the effect of the present invention has been described in the above-mentioned embodiment with the unconstrained zinc alloy, the amount of added mercury is from several ppm to several ppm.
The effect is sufficient even in the case of extremely low levels of several tens of ppm.

[0074]

As described above, according to the present invention, in a zinc alkaline battery, a zinc alloy having a proper composition in a gel-like alkaline electrolyte and a proper synthesis method are provided to have proper physical properties. By adding indium hydroxide, even in the case of anhydrous silver, the increase in battery internal pressure due to zinc corrosion can be suppressed, and the leakage resistance of the battery can be improved more than expected.

By adding an appropriate amount of an organic inhibitor having an appropriate structural formula to this, it is possible to provide a non-polluting zinc-alkaline battery having better storability.

[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

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Junichi Asaoka             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd.

Claims (8)

[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 member selected from the group consisting of lead, bismuth, calcium and aluminum is used as an active material, and polyalkoxy ethylene alkyl phenyl ether represented by the chemical formula 1 is used in the alkaline electrolyte. A method for producing a zinc alkaline battery, characterized by containing 0.001 to 0.1 wt% of a surfactant based on the zinc alloy. [Chemical 1] 2. 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 and aluminum is used as an active material, an indium salt is used as a starting material in the alkaline electrolyte, and synthesis is performed by neutralization treatment in an aqueous solution thereof. Added indium hydroxide is 0.005-0.5 wt% with respect to the zinc alloy
In addition, polyoxy represented by (Chemical Formula 2)
A process for producing a zinc alkaline battery, characterized in that an ethylene alkyl / phenyl ether type surfactant is contained in an amount of 0.001 to 0.1 wt% with respect to the zinc alloy. [Chemical 2] 3. Indium is 0.01 to 1 wt%, and one or two of lead and bismuth is 0.005 to 0.5 in total.
The method for producing a zinc alkaline battery according to claim 1 or 2, wherein a zinc alloy containing wt% is used as a negative electrode active material. 4. Indium is 0.01 to 1 wt%, and one or two of lead and bismuth is 0.005 to 0.5 in total.
3. A zinc alkaline battery according to claim 1, wherein a zinc alloy containing 0.005 to 0.2 wt% of wt% and one or two of calcium and aluminum in total is used in the negative electrode active material. Manufacturing method. 5. The method for producing a zinc alkaline battery according to claim 2, wherein the indium salt is indium chloride or indium sulfate. 6. The method for producing a zinc alkaline battery according to claim 2, wherein the indium salt is indium nitrate or indium sulfate, and indium hydroxide synthesized by neutralization treatment from an aqueous solution containing chloride ions is used. 7. The method for producing a zinc alkaline battery according to claim 2, wherein the synthesized indium hydroxide contains particles having a particle size of 0.5 to 8 μm in an amount of 60 wt% or more of the total amount. 8. The method for producing a zinc alkaline battery according to claim 2, wherein the synthesized indium hydroxide has a weight loss rate of 18 to 30 wt% due to thermal decomposition up to 900 ° C.