JPH0697611B2 - Zinc alkaline battery manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to zinc as a negative electrode active material, an alkaline aqueous solution as an electrolytic solution, manganese dioxide, silver oxide as a positive electrode active material,
The present invention relates to a method for producing a zinc-alkali battery that is pollution-free, has excellent storage properties, and is excellent in discharge performance, regardless of the technology for producing a silver-alkali battery using anhydrous mercury.

Conventional technology About 10 years ago, there has been a strong concern about environmental pollution due to mercury in waste batteries, and research has been conducted 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 typified by the problem of ozone layer depletion caused by CFCs, there is a growing concern over environmental destruction caused by industrial products worldwide, and there is a growing demand for complete elimination of mercury in alkaline batteries.

The approach for the anhydrous mercury technology of alkaline batteries is
It has been made since the time when the alkaline dry battery containing mercury was developed, and many applications and announcements have been made in patents and reports for various materials related to zinc alloys, inorganic inhibitors and organic inhibitors.

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 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 1-
42576), a method of using indium oxide and indium hydroxide as an inorganic inhibitor (Japanese Patent Publication No. 51-3645).
0, JP-A-49-112125, Proceedings of the 56th Electrification Congress: Presentation No. 3G05; page 205), and a method of adding indium oxide and cadmium oxide in combination (JP-A-1-105466). There are also examples in which they are added as additives to the negative electrode of secondary batteries (JP-A-61-96666 and JP-A-61-101955).

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In a battery in which pure zinc is used as the active material of the negative electrode as it is as anhydrous silver,
There is a problem that the corrosion reaction accompanied by the hydrogen generation of zinc occurs violently, the internal pressure of the battery increases, the electrolyte is pushed out, and the leakage resistance is lowered.

Further, in the 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 the mercury that suppressed the corrosion reaction disappeared by increasing the hydrogen overvoltage on the zinc surface.

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 used, the battery cannot be made leak-proof even after partial discharge if the battery is constructed with anhydrous silver.

Further, even in a battery constituted 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, it is practical as a battery constituted only by the above corrosion resistant alloy. Leakage resistance of the battery cannot be secured.

Furthermore, even if a battery is formed by adding an amine-based surfactant that is effective in reducing mercury to a gel negative electrode that uses a corrosion-resistant zinc alloy containing indium, aluminum, and lead as an active material of the negative electrode, Leakage resistance of the battery after partial discharge cannot be ensured.

As described above, the seeds so far have not been completely effective in suppressing corrosion, and are not practical for at least a sealed battery.

In realizing the realization of anhydrous silver in alkaline dry batteries, the present inventors have developed a combined effect of a corrosion-resistant zinc alloy, an inorganic inhibitor and an organic inhibitor,
We examined the materials that can exert the maximum effect, and their optimum state and concentration.

Means for Solving the Problems First, the constitution of the present invention for the combined use of a corrosion resistant zinc alloy and an inorganic inhibitor will be described. The gelled negative electrode in the present invention includes indium, lead, bismuth, calcium,
And aluminum in a proper combination and in a proper amount in an appropriate amount, the corrosion-resistant zinc alloy powder is used as the active material, and the indium hydroxide powder having the proper properties is dispersed at a proper concentration. It is composed of gelled alkaline electrolyte.

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

Next, the constitution of the present invention for the combined use of a zinc alloy, an inorganic inhibitor and an organic inhibitor will be described. The gelled negative electrode of the present invention contains indium, lead, bismuth, calcium, and aluminum in a proper combination in a proper amount in a proper amount and a corrosion-resistant zinc alloy powder, and indium hydroxide powder having proper properties. Disperse the concentration,
Further, it is composed of a gel-like alkaline electrolyte containing an appropriate amount of a so-called perfluoroalkyl polyethylene oxide-based surfactant having polyethylene oxide in a hydrophilic part and an fluorinated alkyl group in a lipophilic part as an organic inhibitor. .

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

In addition, the corrosion-resistant zinc alloy contains 0.01 to 1 wt% indium and 0.005 to 0.5 wt in total of one or two of lead and bismuth.
% Zinc alloy or indium 0.01-1wt%
%, One or two of lead and bismuth in total 0.005
It is a zinc alloy containing 0.5 wt% to 0.5 wt% and 0.005 to 0.2 wt% of one or two kinds of calcium and aluminum in total. Moreover, the suitable addition amount of indium hydroxide is 0.005-0.5 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 made 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, it is effective that the weight reduction rate of indium hydroxide due to thermal decomposition up to 900 ° C. is 18 to 30% by weight, preferably 20 to 25%.

The effect of 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 are the result of intensive research so as to maximize the composite effect. .
The elucidation of the mechanism of action is unclear at present, but it is speculated as follows.

First, the action effects of the additive element of the alloy, 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 overvoltage of these elements themselves, and are added to zinc to have an 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. Further, 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 the gel alkaline electrolyte in the coexistence state with the zinc alloy, a part of the indium hydroxide is electrodeposited on the surface of the zinc alloy by the principle of displacement plating, and the hydrogen overvoltage on the surface is increased. The remaining part remains solid in the electrolyte, and when a new zinc alloy surface appears due to discharge,
Electrodeposited on the new surface to show anticorrosion effect.

When a surfactant coexists with a zinc alloy in a gel alkaline electrolyte, the surfactant chemisorbs on the surface of the zinc alloy to form a hydrophobic monomolecular layer by the principle of metallic soap, and exhibits a corrosion prevention effect. In particular,
Surfactants with polyethylene oxide in the hydrophilic part
It has a high solubility as a micelle in an alkaline electrolyte, and when it is added to the electrolyte, it rapidly migrates and is adsorbed on the surface of the zinc alloy, and thus has a high anticorrosion effect. Furthermore, if a fluorinated alkyl group is held in the lipophilic part, when it is adsorbed on the surface of the zinc alloy, it has a high electrical insulation property, so it effectively rejects the electron transfer of the corrosion reaction, and because it has a strong alkali resistance, its effect. Lasts.

Next, the combined effect of the 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, the generation of hydrogen gas is suppressed on the surface of the zinc alloy having good corrosion resistance, and the electrodeposition is performed smoothly and uniformly, 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 no substance that acts after partial discharge.
It is considered that the surfactant, in addition to its own function, serves to suppress the electrodeposition of indium more than necessary and to secure the amount to act after partial discharge.

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 synthesis method of 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 anticorrosion 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. In addition, in the synthesis using indium nitrate and indium sulfate as starting materials, indium hydroxide having the same properties as the synthesis using indium chloride as a starting material can be synthesized by performing neutralization treatment in an aqueous solution containing chloride ions.

Examples Hereinafter, details and effects of the present invention will be described with reference to examples.

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

Corrosion resistant zinc alloy powder melts 99.97% pure zinc,
A predetermined amount of a predetermined additive element was added and uniformly dissolved, and then sprayed with compressed air to form a powder, which was prepared by a so-called atomization method, and this was classified by a sieve to adjust the particle size range to 45 to 150 mesh.

For indium hydroxide, a predetermined amount of indium salt is added to ion-exchanged water in a saturated amount, and the pH of the aqueous solution is adjusted to 9 with ammonia gas as a neutralizing agent while stirring the aqueous solution with a screw stirrer.
Until neutralized. After that, wash it with ion-exchanged water on a filter with a roughness of 0.5μ until the pH of the solution becomes 7.5, pull a vacuum from under the filter to separate the water, and vacuum dry at 60 ° C. Synthesized.

The gelled negative electrode was prepared as follows. First, add 3 wt% to 40 wt% potassium hydroxide solution (containing 3 wt% ZnO).
Gelation is carried out by adding sodium polyacrylate (1) and 1% by weight of carboxymethyl cellulose. Then, a predetermined amount of indium hydroxide powder is gradually added while stirring the gel electrolyte, 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. In addition, when adding an organic inhibitor, a step of adding a predetermined amount of this to the gel electrolyte and aging for 2 to 3 hours was added before the addition of indium hydroxide in the above adjusting step.

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 is a battery outer can, and 8 is a case 6
A polyethylene resin sealing body for closing the opening of the above, and a bottom plate 9 forming a negative electrode terminal.

The method of comparative evaluation of leakage resistance is to prototype 100 alkaline manganese batteries shown in Fig. 1 by 100 and perform partial discharge to a theoretical capacity of 20% at a constant current of 0.85A, which is the most severe condition for LR6. The test was performed, and the number of batteries that leaked after storage at 60 ° C for 30 days or more was evaluated as a leak index (%). Under such harsh conditions, 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 and an inorganic inhibitor will be described.

First, for zinc alloys, various additive elements were studied in advance with various changes in composition. As a result, indium is an essential alloy component, and a zinc alloy containing lead and bismuth individually or in combination with it, or indium is an essential component in which lead and bismuth are contained individually or in combination and further calcium. It has been found that a zinc alloy system containing aluminum and aluminum alone or in combination is good alone. Table 1 shows the best alloy composition group among them.

Table 2 shows the results of the liquid leakage test after storage at 60 ° C. for 30 days in batteries prepared by changing the amount of indium hydroxide added to the various zinc alloys in Table 1 above.

It can be seen from Table 2 that even a zinc alloy having excellent corrosion resistance cannot ensure very practical liquid leakage resistance by itself, but the liquid leakage resistance can be secured by adding an appropriate amount of indium hydroxide. The amount of indium hydroxide added to each zinc alloy is preferably in the range of 0.005 to 0.5 wt%.

In Table 3, the amount of indium hydroxide added was fixed at 0.1 wt%,
60 ℃ of batteries made by changing the amount of alloying elements
The results of the leakage test after storage for 30 days are shown.

From Table 3, the amount of indium added to the zinc alloy is 0.01-1w
It can be seen that t%, lead and bismuth each alone or in total 0.005 to 0.5 wt%, and calcium and aluminum individually or in total 0.005 to 0.2 wt% are suitable.

In this embodiment, indium hydroxide synthesized by neutralizing an aqueous solution of sulfate is used as a starting material, but indium hydroxide having a chloride or nitrate as a starting material can also be used. Those effects were higher in the order of those using chloride as the starting material, those using sulfide as the starting material, and those using nitrate as the starting material.

Example 2 When a zinc alloy and an inorganic inhibitor were added in combination,
The present invention is described with respect to the limitation of starting materials in the synthesis of indium hydroxide.

Table 4 shows the results of the liquid leakage test of batteries in which 0.1 wt% of indium hydroxide having different starting materials was added to each zinc alloy after storage at 60 ° C for 45 days.

It can be seen from Table 4 that nitrates that are synthesized in the presence of chlorine ions are also suitable. By the way, even if the nitrate is used as the starting material, the leakage index is 0% at 60 ° C on the 30th day, which is at a practical level. However, the leak index of batteries using chlorides and sulfates as starting materials is 0% up to 45 days at 60 ° C, and long-term reliability is obtained.

Example 3 When a zinc alloy and an inorganic inhibitor were added in combination,
An example for limiting the particle size range of indium hydroxide will be described.

Table 5 shows the results of the leakage test after 45 days at 60 ° C. of the battery in which 0.1 wt% of indium hydroxide having different particle size distribution was added to each zinc alloy.

From Table 5, 60 wt% of particles with a particle size in the range of 0.5-8μ
It is preferable to use indium hydroxide powder containing the above (since the particles left on the filter having a roughness of 0.5 μ in the synthetic water washing step are used, the remaining particles are particles of 0.5 μ or more). If the amount of these particles is 70 wt% or more, the liquid may not leak at 60 ° C for 60 days.

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

Example 4 An example of limiting the thermal decomposition loss of indium hydroxide in the case where a zinc alloy and an inorganic inhibitor are compounded will be described.

Table 6 shows 60 ° C of batteries with 0.1wt% addition of indium hydroxide with different thermal decomposition weight loss up to 900 ° C.
The results of the leakage test after one day are shown.

From Table 6, it can be seen that it is preferable to use indium hydroxide having a thermal decomposition weight loss of 18 to 30 wt%. If you use indium hydroxide whose thermal decomposition weight loss is 20 to 25%,
May not leak even on the first day.

The indium hydroxides having different heating weight loss rates used in this example were prepared by using chloride as a starting material and changing the time of the neutralization treatment.

Example 5 An example in which a zinc alloy, an inorganic inhibitor and an organic inhibitor are added in combination will be described.

Table 7 shows that the amount of indium hydroxide added to each zinc alloy was fixed at the optimum value of 0.1 wt% and the amount of the surfactant added as an organic inhibitor was changed to 60 ° C.
The results of the liquid leakage test after storage for a day are shown.

From this, the amount of surfactant added was 0.001 for each zinc alloy.
It can be seen that ~ 0.1 wt% is suitable.

Table 8 shows the optimum amount of surfactant added for each zinc alloy.
The results of the leakage test after 60 days of storage at 60 ° C of batteries prepared by fixing the amount of indium hydroxide fixed to 01 wt% are shown.

From this, it can be seen that an appropriate amount of indium hydroxide added is 0.005 to 0.5 wt%.

Table 9 shows the optimum amount of surfactant added for each zinc alloy.
Optimum addition amount of indium hydroxide to 01wt% 0.1wt%
The results of the leak test after storage for 60 days at 60 ° C of batteries prepared by fixing the alloys to the above and changing the additive elements of the alloys and the amounts thereof added are shown.

From this, the amount of indium added to the zinc alloy is 0.01-1w
t%, lead and bismuth each alone or in total 0.005 to 0.5 wt%, and calcium and aluminum individually or in total 0.005 to 0.2 wt%
It turns out that% is appropriate. In this case, the liquid leakage resistance is significantly improved as compared with the case where no surfactant is added.

The surfactant used in Example 5 has polyethylene oxide alcohol (polymerization degree = 20) in the hydrophilic part, the lipophilic part has a fluorinated alkyl group (carbon chain number = 7), and the bonding part is an alkyl group. It is a perfluoroalkyl polyethylene oxide surfactant. The same effect can be obtained when the degree of polymerization of the polyethylene oxide chain is in the range of 10 to 40 and the carbon number of the fluorinated alkyl group is 3 to 10. Also, indium hydroxide uses sulfate as a starting material, and its particle size is
A powder containing 80 wt% or more of particles in the range of 0.5 to 8 μm and having a thermal decomposition weight loss of 22 wt% was used, but the same starting materials as shown in Example 2, Example 3 and Example 4 were used. It has been confirmed that indium hydroxide having a resistance to liquid leakage can provide sufficient or higher resistance to liquid leakage.

By the way, in all the examples, the effect of the present invention has been described by using the unsolicited zinc alloy, but the effect is sufficient even in the case of ultra-low degree of addition of mercury of several PPM to several tens of PPM.

Effect of the Invention As described above, according to the present invention, in a zinc alkaline battery, a zinc alloy having a proper composition in a gel alkaline electrolyte and water synthesized to have proper physical properties by a proper synthesis method. By adding indium oxide, even in anhydrous silver, the increase in battery internal pressure due to gas generation due to corrosion of zinc can be suppressed and the liquid leakage resistance of the battery can be improved. Then, by adding an organic inhibitor thereto, it is possible to provide a pollution-free zinc-alkaline battery having a better storability.

[Brief description of drawings]

FIG. 1 is a sectional view of an alkaline manganese battery according to an embodiment of the present invention. 1 ... Positive electrode mixture, 2 ... Gelled negative electrode, 3 ... Separator

Claims (14)

[Claims] 1. In the preparation of a gelled negative electrode in which zinc alloy powder is mixed and dispersed in a gelled alkaline electrolyte, indium,
Using a zinc alloy containing at least one or more of the group of lead, bismuth, calcium and aluminum as an active material,
Zinc alkali, characterized in that the alkaline electrolyte contains indium hydroxide as a starting material and indium hydroxide synthesized by neutralization treatment in an aqueous solution thereof is contained in an amount of 0.005 to 0.5 wt% with respect to the zinc alloy. Battery manufacturing method. 2. A zinc alloy containing 0.01 to 1 wt% of indium and 0.005 to 0.5 wt% of one or two of lead and bismuth in total is used as a negative electrode active material. The method for producing a zinc alkaline battery according to the item. 3. Indium is 0.01 to 1 wt%, one or two kinds of lead and bismuth is 0.005 to 0.5 wt% in total, and one or two kinds of calcium and aluminum is 0.00 in total.
The method for producing a zinc alkaline battery according to claim 1, wherein a zinc alloy containing 5 to 0.2 wt% is used as a negative electrode active material. 4. The method for producing a zinc alkaline battery according to claim 1, wherein the indium salt is indium chloride or indium sulfate. 5. The method for producing a zinc alkaline battery according to claim 1, 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. . 6. The method for producing a zinc alkaline battery according to claim 1, wherein the synthesized indium hydroxide contains particles having a particle diameter of 0.5 to 8 μm in an amount of 60 wt% or more of the total amount. 7. The method for producing a zinc alkaline battery according to claim 1, wherein the synthesized indium hydroxide has a weight loss rate of 18 to 30 wt% due to thermal decomposition up to 900 ° C. 8. In preparing a gelled negative electrode prepared by mixing and dispersing zinc alloy powder in a gelled alkaline electrolyte, indium,
Using a zinc alloy containing at least one or more of the group of lead, bismuth, calcium and aluminum as an active material,
Indium salt is used as a starting material in the alkaline electrolyte, and 0.005 to 0.5 wt% of indium hydroxide synthesized by neutralization treatment in an aqueous solution thereof is contained with respect to the zinc alloy,
A process for producing a zinc-alkali battery, further comprising a surfactant having polyethylene oxide in a hydrophilic part and a fluoroalkyl group in a lipophilic part in an amount of 0.001 to 0.1 wt% with respect to the zinc alloy. 9. A negative electrode active material comprising a zinc alloy containing 0.01 to 1 wt% indium and 0.005 to 0.5 wt% in total of one or two of lead and bismuth. The method for producing a zinc alkaline battery according to the item. 10. Indium is 0.01 to 1 wt%, one or two kinds of lead and bismuth is 0.005 to 0.5 wt% in total, and one or two kinds of calcium and aluminum is 0.
9. The method for producing a zinc alkaline battery according to claim 8, wherein a zinc alloy containing 005 to 0.2 wt% is used as the negative electrode active material. 11. The method for producing a zinc alkaline battery according to claim 8, wherein the indium salt is indium chloride or indium sulfate. 12. The method for producing a zinc alkaline battery according to claim 8, wherein the indium salt is indium nitrate or indium sulfate, and indium hydroxide synthesized by a neutralization treatment from an aqueous solution containing chloride ions is used. Law. 13. The method for producing a zinc alkaline battery according to claim 8, wherein the synthesized indium hydroxide contains particles having a particle diameter of 0.5 to 8 μm in an amount of 60 wt% or more of the total amount. 14. The method for producing a zinc alkaline battery according to claim 8, wherein the synthesized indium hydroxide has a weight loss rate of 18 to 30 wt% due to thermal decomposition up to 900 ° C.