JP5400498B2 - Alkaline primary battery and manufacturing method thereof - Google Patents

Description

  The present invention relates to an alkaline primary battery, and relates to an additive for an electrolytic solution used in an alkaline primary battery.

  Conventionally, nickel-metal hydride storage batteries, secondary batteries such as lithium ion secondary batteries, and primary batteries such as alkaline batteries and manganese batteries have been widely used as power sources for electronic devices such as portable devices. In recent years, the demand for battery performance has increased with the improvement in performance of devices.

Various studies have been conducted on secondary batteries for the purpose of improving battery performance.
For example, Patent Document 1 proposes adding CsOH or RbOH to an alkaline electrolyte in a nickel-metal hydride storage battery including a positive electrode including nickel hydroxide and a negative electrode including a hydrogen storage alloy. Thereby, the cycle life is long, and the utilization factor of the active material can be kept high even when the battery is used in a low temperature region.

Moreover, in patent document 2, in the alkaline storage battery (secondary battery) provided with the positive electrode containing nickel hydroxide, the negative electrode containing cadmium hydroxide or a hydrogen storage alloy, Sr etc. on the positive electrode active material surface which has nickel hydroxide as a main component. It has been proposed to form a compound layer containing Cs, and to further include metal ions such as Cs and Rb in the compound layer. As a result, the conductivity of the positive electrode active material is improved, and the quick charge characteristics of the battery are improved. Patent Documents 1 and 2 are intended to improve the performance specific to the secondary battery, such as the quick charge characteristics and the cycle life characteristics. Thus, it has been proposed to improve the characteristics of the positive electrode for secondary batteries mainly composed of nickel hydroxide.

Various studies have also been conducted on primary batteries for the purpose of improving battery performance.
In an alkaline primary battery including a positive electrode containing manganese dioxide, a negative electrode containing zinc, and an alkaline electrolyte, zinc oxide having low conductivity is deposited at the negative electrode at the end of discharge, and the polarization of the negative electrode increases rapidly, and the discharge voltage increases. There is a problem that it is likely to drop rapidly. In particular, during high-load discharge, the decrease in discharge voltage due to the increase in polarization was significant.

JP-A-6-283195 JP 2001-283840 A

  Therefore, the present invention provides an alkaline primary battery having excellent discharge characteristics in which increase in polarization of the negative electrode due to a decrease in conductivity of the negative electrode active material at the end of discharge is suppressed in order to solve the above-described conventional problems. With the goal. Moreover, it aims at providing the manufacturing method of the alkaline primary battery.

The present invention includes a positive electrode including manganese dioxide as a positive electrode active material and graphite as a conductive agent, a negative electrode including zinc or a zinc alloy as a negative electrode active material, a separator disposed between the positive electrode and the negative electrode, and an alkaline primary battery comprising an electrolytic solution, said electrolytic solution, Ru aqueous der containing at least one of CsOH and RbOH as KOH, and additives.
Additive concentration of the electrolytic solution, Ru 0.1 to 2% by mass.
The KOH concentration in the electrolytic solution is preferably 25 to 36% by mass .
When the additive is CsOH, the concentration of the additive in the electrolytic solution is preferably 0.5 to 2% by mass. When the electrolytic solution contains both CsOH and RbOH as the additive, the mass ratio of CsOH to RbOH is preferably 20:80 to 80:20.

In addition, the method for producing an alkaline primary battery of the present invention includes
(1) A step of obtaining a first electrolytic solution comprising an aqueous solution containing KOH and at least one of CsOH and RbOH as an additive,
(2) A step of obtaining a negative electrode by mixing zinc or a zinc alloy that is a negative electrode active material, a gelling agent, and the first electrolytic solution obtained in the step (1),
(3) A step of obtaining a hollow cylindrical positive electrode containing manganese dioxide as a positive electrode active material, graphite as a conductive agent, and a second electrolytic solution,
(4) a step of arranging the positive electrode in a battery case;
(5) the separator is disposed on the inner surface of the hollow portion of the positive electrode, after pouring the third electrolyte to the separator, the step of filling the positive electrode wherein through the separator into the hollow portion negative electrode of the well, ( 6) A step of arranging a sealing member in the opening of the battery case to obtain an alkaline primary battery ,
Only contains a concentration of the additive of the total electrolyte solution contained in the alkaline primary battery is a 0.1 to 2 mass%.

The concentration of the additive of the first electrolytic solution in the step (1) is preferably from 0.2 to 4 mass%.
The KOH concentration in the first electrolyte solution in the step (1) is preferably 29 to 37% by mass .
The KOH concentration in the third electrolyte solution in the step (5) is preferably 29 to 37% by mass .

  ADVANTAGE OF THE INVENTION According to this invention, the alkaline primary battery which has the outstanding discharge characteristic in which the polarization increase of the negative electrode by the electroconductive fall of the negative electrode active material in the end stage of discharge was suppressed can be provided. Excellent discharge characteristics can be obtained at any of low, medium, and high loads.

It is the front view which made a part of AA alkaline dry battery which is one embodiment of the alkaline primary battery of the present invention a section.

  The present invention includes a positive electrode including manganese dioxide as a positive electrode active material and graphite as a conductive agent, a negative electrode including zinc or a zinc alloy as a negative electrode active material, a separator disposed between the positive electrode and the negative electrode, and The present invention relates to an alkaline primary battery including an alkaline electrolyte. The present invention is characterized in that the electrolytic solution is an aqueous solution containing KOH and at least one of CsOH and RbOH as an additive. The electrolytic solution is contained in the positive electrode, the negative electrode, and the separator.

In the negative electrode of an alkaline primary battery, a reaction that generates Zn (OH) ₄ ^{2− represented} by the following formula (1) occurs during discharge.
Zn + 4OH ⁻ → Zn (OH) ₄ ²⁻ + 2e ⁻ (1)

When the discharge proceeds and reaches the end of the discharge, a reaction in which Zn (OH) ₄ ²⁻ changes to ZnO easily occurs as shown in the following formula (2). When ZnO precipitates on the surface of the negative electrode active material, the conductivity of the negative electrode decreases and the polarization increases.
Zn (OH) ₄ ²⁻ → ZnO + H ₂ O + 2OH ⁻ (2)

  In contrast, in the present invention, at least one of CsOH and RbOH having a degree of ionization higher than that of KOH is added to an electrolytic solution composed of an aqueous KOH solution of an alkaline primary battery, thereby generating a reaction (formation of ZnO). ) Is suppressed. Therefore, an increase in polarization due to the formation of ZnO at the negative electrode at the end of discharge is suppressed, and the discharge characteristics are improved. Excellent discharge characteristics can be obtained not only at low and medium loads, but also at high loads.

The concentration of the additive in the electrolytic solution in the battery is preferably 0.02 to 7% by weight.
Here, the electrolytic solution in the battery refers to the entire electrolytic solution contained in the power generation element composed of the positive electrode, the negative electrode, and the separator.
The additive concentration in the electrolytic solution in the battery can be obtained, for example, by the following method. The negative electrode is taken out from the battery after production (for example, after 1 to 4 weeks have passed since production), and the concentration of the additive in the electrolyte solution in the negative electrode is measured. And the said additive concentration of the electrolyte solution which exists in the negative electrode in a battery is calculated | required as the said additive concentration in the electrolyte solution in a battery.
If the concentration of the additive in the electrolyte in the battery is less than 0.02% by weight, the effect of the additive may not be sufficiently obtained. When the concentration of the additive in the electrolytic solution in the battery exceeds 7% by weight, the high load discharge characteristics may be deteriorated. In order to obtain more excellent discharge characteristics, the concentration of the additive in the electrolytic solution in the battery is more preferably 0.1 to 5% by weight, and further preferably 0.1 to 2% by weight.

  In order to obtain excellent medium load discharge characteristics, the additive is preferably RbOH. When importance is attached to the material cost, the additive is preferably CsOH. From the viewpoint of discharge characteristics and material cost, when CsOH and RbOH are used in combination as an additive, the mixing weight ratio between them is preferably 20-80: 80-20, more preferably 30-70: 70- 30.

The KOH concentration in the electrolytic solution in the battery is preferably 25 to 36% by weight. When the KOH concentration in the electrolytic solution in the battery is 25% by weight or more, the ionic conductivity of the electrolytic solution is improved, and the discharge characteristics are greatly improved. When the KOH concentration in the electrolytic solution in the battery exceeds 36% by weight, the ionic conductivity of the electrolytic solution is lowered, and the high-load discharge characteristics may be lowered.
In order to obtain excellent high-load discharge characteristics, the KOH concentration in the electrolyte solution in the battery is more preferably 30 to 36% by weight. In order to obtain excellent medium load discharge characteristics, the KOH concentration in the electrolyte in the battery is more preferably 27 to 34% by weight. In order to obtain excellent low-load discharge characteristics, the KOH concentration in the electrolytic solution is more preferably 25 to 32% by weight.

The electrolyte preferably further contains ZnO in order to suppress leakage due to hydrogen gas generation in the negative electrode. The ZnO concentration in the electrolytic solution in the battery is preferably 1 to 3% by weight. When the ZnO concentration in the electrolytic solution exceeds 3% by weight, the discharge characteristics may deteriorate. The KOH concentration in the electrolyte in the battery is preferably 27 to 33% by weight and the ZnO concentration is preferably 1 to 3% by weight.
The KOH concentration and ZnO concentration in the electrolytic solution in the battery can be obtained, for example, by the following method. The negative electrode is taken out from the battery after manufacture (for example, after 1 to 4 weeks have elapsed since manufacture), and the KOH concentration and ZnO concentration in the electrolyte solution in the negative electrode are measured. Then, the KOH concentration and ZnO concentration of the electrolytic solution present in the negative electrode in the battery are obtained as the KOH concentration and ZnO concentration in the electrolytic solution in the battery.
In addition, when a battery is constituted by using an electrolytic solution having a KOH concentration of 29 to 37% by weight for negative electrode preparation, positive electrode preparation, and injection, and using electrolytic manganese dioxide (EMD) as a positive electrode active material, manufacturing is performed. When the KOH concentration in the electrolyte in the battery after measurement (for example, after 1 to 4 weeks has elapsed since manufacture) is 25 to 36% by weight, which is higher than the KOH concentration in the electrolyte used in the production of the battery. Slightly lower. This is presumably because sulfate radicals (for example, manganese sulfate) attached to the EMD during the production of the EMD cause a neutralization reaction with a part of KOH in the electrolytic solution.

The method for adding the additive to the electrolytic solution is not particularly limited as long as the additive is contained in the electrolytic solution during battery production.
In order to obtain the effect of the additive more reliably, it is preferable to add the additive to the electrolytic solution used in preparing the gelled negative electrode. In addition to this, the additive may be included in an electrolytic solution used when preparing a positive electrode mixture, or may be included in an electrolytic solution poured into a separator (inside the battery) when preparing a battery. In any case, the additive is finally dispersed throughout the power generation element (positive electrode mixture, gelled negative electrode, and separator) in the battery.
In order to easily adjust the KOH concentration, it is preferable that the electrolytic solution for producing the positive electrode, the electrolytic solution for producing the negative electrode, and the electrolytic solution for injecting the separator have the same KOH concentration.
In the case of ZnO, it may be added by the same method as in the case of the additive.

Moreover, the manufacturing method of the alkaline primary battery of this invention is a method of adding the said additive to the electrolyte solution used at the time of negative electrode preparation.
That is, the method for producing an alkaline primary battery of the present invention includes:
(1) A step of obtaining an electrolytic solution comprising an aqueous solution containing KOH and at least one of CsOH and RbOH as an additive,
(2) A step of obtaining a negative electrode by mixing zinc or a zinc alloy as a negative electrode active material, a gelling agent, and the electrolytic solution obtained in the step (1),
(3) obtaining a hollow cylindrical positive electrode containing manganese dioxide as a positive electrode active material, graphite as a conductive agent, and an electrolyte;
(4) a step of arranging the positive electrode in a battery case;
(5) placing a separator on the inner surface of the hollow part of the positive electrode, injecting an electrolyte into the separator, and then filling the negative electrode into the hollow part of the positive electrode through the separator; and (6) Arranging a sealing member in the opening of the battery case;
including.

[Step (1)]
The electrolytic solution containing the additive in the step (1) is used for producing the negative electrode in the step (2).
The additive concentration in the electrolytic solution in the step (1) is preferably 0.04 to 14% by weight. If the additive concentration in the electrolytic solution in step (1) is less than 0.04% by weight, the effect of the additive may not be sufficiently obtained. When the additive concentration in the electrolytic solution in the step (1) exceeds 14% by weight, the high rate discharge characteristics may be deteriorated.
In order to obtain more excellent discharge characteristics, the additive concentration in the electrolytic solution in the step (1) is more preferably 0.2 to 10% by weight, and further preferably 0.2 to 4% by weight. .
A gelled negative electrode is prepared using an electrolytic solution having an additive concentration of 0.04 to 14% by weight, but the entire electrolytic solution (positive electrode mixture, separator and gelled negative electrode) present in the finally obtained battery. What is necessary is just to set an additive concentration suitably within the said range so that the additive concentration with respect to the total amount of electrolyte solution in it may be 0.02 to 7 weight%.

The KOH concentration in the electrolytic solution in the step (1) is preferably 29 to 37% by weight, more preferably 31 to 35% by weight. When the KOH concentration in the electrolytic solution in the step (1) is 29% by weight or more, the ionic conductivity of the electrolytic solution is improved, and the discharge characteristics are greatly improved. When the KOH concentration in the electrolytic solution in the step (1) exceeds 37% by weight, the ionic conductivity of the electrolytic solution may be lowered, and the high load discharge characteristics may be lowered.
A gelled negative electrode is prepared using an electrolytic solution having a KOH concentration of 29 to 37% by weight, but the entire electrolytic solution present in the battery finally obtained (positive electrode mixture, separator and electrolysis in the gelled negative electrode) The KOH concentration may be appropriately set within the above range so that the KOH concentration with respect to the total amount of the liquid is 25 to 36% by weight.

[Step (2)]
In step (2), a negative electrode is produced using the electrolytic solution containing the additive obtained in step (1).
In the step (2), for example, the negative electrode is obtained by mixing and dispersing zinc alloy powder as a negative electrode active material in a gel electrolyte obtained by adding a gelling agent to the electrolyte obtained in the step (1). Is obtained.

  As the negative electrode active material, powdery zinc or a zinc alloy is used. It is preferable to use a zinc alloy having excellent corrosion resistance, and it is more preferable that mercury, cadmium, lead, or all of them are not added in consideration of the environment. For example, the zinc alloy preferably contains elements such as indium, bismuth, and aluminum. These elements may be used alone or in combination of two or more. The zinc alloy preferably includes 0.01 to 0.1 wt% indium, 0.005 to 0.02 wt% bismuth, and 0.001 to 0.005 wt% aluminum. It is preferable to use 70SA-H (Al, Bi, and In contents of 50 ppm, 50 ppm, and 200 ppm, respectively) manufactured by Mitsui Kinzoku Co., Ltd. as the zinc alloy.

The amount of the electrolytic solution added in the step (2) is preferably 50 to 60 parts by weight per 100 parts by weight of the negative electrode active material.
As the gelling agent, for example, sodium polyacrylate is used.
The addition amount of the gelling agent is preferably 1 to 5 parts by weight per 100 parts by weight of the negative electrode active material.

[Step (3)]
In the step (3), for example, a granular mixture (for example, a particle size of 38 to 1000 μm) composed of a positive electrode active material, a conductive agent, and an electrolytic solution is obtained, and this is pressed into a hollow cylinder, thereby forming a hollow cylinder. In the form of a positive electrode mixture pellet.
As the positive electrode active material, powdered electrolytic manganese dioxide (for example, HH-TF7 manufactured by Tosoh Corporation) is used. The particle size of the electrolytic manganese dioxide is, for example, 0.1 to 100 μm.
As the conductive agent, powdery graphite (for example, SP-20 manufactured by Nippon Graphite Co., Ltd.) is used. The particle diameter of graphite is, for example, 3 to 30 μm.
The amount of graphite added is preferably 6 to 10 parts by weight per 100 parts by weight of the positive electrode active material.
Further, as the positive electrode active material, manganese dioxide and nickel oxyhydroxide may be used in combination. In this case, it is preferable to use 5 to 50 parts by weight of nickel oxyhydroxide per 100 parts by weight of manganese dioxide.

It is preferable that the addition amount of the electrolyte solution used for producing the positive electrode in the step (3) is 0.8 to 3 parts by weight per 100 parts by weight of the positive electrode active material.
When using an electrolytic solution having the same KOH concentration as the electrolytic solution for preparing the negative electrode and for pouring, the electrolytic solution used in step (3) is preferably a KOH aqueous solution having a concentration of 29 to 37% by weight.
Also, when filling a predetermined molding die with the above granular mixture and pressing to obtain a hollow cylindrical positive electrode mixture pellet, in order to prevent the molding die from rusting In the step (3), it is preferable to use a 36 to 42% by weight high-concentration KOH aqueous solution for the electrolytic solution.
If necessary, a binder such as polyethylene powder or a lubricant such as stearate may be added to the above mixture.

[Step (4)]
In step (4), for example, a plurality of hollow cylindrical positive electrode mixture pellets are placed in the battery case, and then pressed again, and the positive electrode mixture pellets are brought into close contact with the inner surface of the battery case. An agent is placed in the battery case.
In order to reduce the contact resistance between the battery case and the positive electrode mixture, it is preferable that a graphite coating (for example, a thickness of 0.1 to 5 μm) is disposed on the inner surface of the battery case.

[Step (5)]
In the step (5), for example, a cylindrical separator sealed at one end is arranged on the inner surface (side surface and bottom surface of the hollow portion) of the positive electrode mixture, and the electrolytic solution is poured into the separator (in the battery case). After the liquid, the gelled negative electrode is filled into the hollow part of the positive electrode mixture through the separator.
For the separator, a microporous sheet excellent in alkali resistance is used. For the separator, for example, a nonwoven fabric mainly composed of polyvinyl alcohol fiber and rayon fiber is used. The thickness of the separator is, for example, 80 to 250 μm.
When the additive is included only in the electrolytic solution used for producing the negative electrode, the electrolytic solution used in step (5) is preferably a KOH aqueous solution having a concentration of 29 to 37% by weight, and a KOH concentration of 31 to 35% by weight. More preferably, it is an aqueous solution. When the KOH concentration in the electrolytic solution in the step (5) is 29% by weight or more, the ionic conductivity of the electrolytic solution is improved, and the discharge characteristics are greatly improved. When the KOH concentration in the electrolytic solution in the step (5) exceeds 37% by weight, the ionic conductivity of the electrolytic solution may be lowered, and the high load discharge characteristics may be lowered.

[Step (6)]
In the step (6), for example, an assembly sealing portion 9 including a resin gasket 5, a nail-shaped negative electrode current collector 6, and a bottom plate 7 also serving as a negative electrode terminal shown in FIG. Is placed in the opening of the battery case to seal the battery case.

The resin sealing body is obtained, for example, by injection molding a resin having excellent alkali resistance and airtightness such as polyamide such as 6,6-nylon or polypropylene to a predetermined size and shape.
The negative electrode current collector is obtained, for example, by pressing a wire such as silver, copper, or brass into a nail shape. In order to eliminate impurities during processing and obtain a concealing effect, the surface is preferably plated with tin or indium.
The bottom plate is obtained, for example, by press-molding a tin-plated steel plate or the like into a predetermined shape.

Hereinafter, an AA alkaline battery which is an embodiment of the alkaline primary battery of the present invention will be described with reference to FIG. FIG. 1 is a front view of a cross section of a part of an AA alkaline battery which is an embodiment of the alkaline primary battery of the present invention.
A positive electrode 2 is inserted into a bottomed cylindrical battery case 1 made of a nickel-plated steel plate. The positive electrode 2 is made of a hollow cylindrical positive electrode mixture containing manganese dioxide as a positive electrode active material and graphite as a conductive material. A graphite coating film (not shown) is formed on the inner surface of the battery case 1.

  A hollow portion of the positive electrode 2 is filled with a negative electrode 6 via a separator 4. The negative electrode 6 is composed of a gelled negative electrode containing zinc powder or zinc alloy powder as a negative electrode active material. The separator is made of a nonwoven fabric mainly composed of polyvinyl alcohol fiber and rayon fiber, for example. The positive electrode 2, the negative electrode 6, and the separator 4 include an electrolytic solution made of an aqueous solution containing KOH and at least one of CsOH and RbOH as an additive.

  The opening of the battery case 1 is sealed by an assembly sealing body 9. The assembly sealing body 9 includes a resin gasket 5, a bottom plate 7 also serving as a negative electrode terminal, and a nail-type negative electrode current collector 6. The negative electrode current collector 6 is inserted into the gelled negative electrode 3. The body of the negative electrode current collector 6 is inserted into a through hole provided in the center of the gasket 5, and the head of the negative electrode current collector 6 is welded to the bottom plate 7. The open end of the battery case 1 is caulked to the peripheral edge of the bottom plate 7 via a gasket 5. The outer surface of the battery case 1 is covered with an exterior label 8.

Examples of the present invention will be described in detail below, but the present invention is not limited to these examples.
Example 1
(1) Production of negative electrode A negative electrode active material, an electrolytic solution, and sodium polyacrylate as a gelling agent are mixed at a weight ratio of 63.9: 35.15: 0.74, and a gelled negative electrode is prepared. Obtained. As the negative electrode active material, a zinc alloy (manufactured by Mitsui Kinzoku Co., Ltd., 70SA-H) was used. An aqueous solution containing KOH (concentration: 33% by weight), ZnO (concentration: 2% by weight), and CsOH was used as the electrolyte for preparing the negative electrode.

(2) Production of positive electrode pellets Electrolytic manganese dioxide (manufactured by Tosoh Corp., HH-TF7) as a positive electrode active material, graphite powder (SP-20M made by Nippon Graphite Co., Ltd.) as a conductive agent, and an electrolyte solution in a weight ratio The mixture was 94: 6: 1.5. This mixture was uniformly stirred and mixed with a mixer, and then sized to a constant particle size. The obtained granular material was filled in a predetermined molding die and subjected to pressure molding to obtain a hollow cylindrical positive electrode pellet. An aqueous solution containing KOH (concentration 39% by weight) and ZnO (concentration 2% by weight) was used as the electrolyte for producing the positive electrode.

(3) Production of Alkaline Primary Battery Using the positive electrode pellet obtained above, an AA alkaline battery shown in FIG. 1 was produced as follows.
Two positive electrode pellets were inserted into a bottomed cylindrical battery case 1 made of a nickel-plated steel sheet having a graphite coating film formed on the inner surface, and then press-molded again in the battery case 1, and the battery case 1 A hollow cylindrical positive electrode 2 in close contact with the inner surface was obtained. After the separator 4 (thickness: 0.25 mm) was disposed inside the positive electrode 2, an alkaline electrolyte was injected into the battery case 1. An aqueous solution containing KOH (concentration 33% by weight) and ZnO (2% by weight) was used as the electrolyte for injection. For the separator 4, a non-woven fabric mainly composed of polyvinyl alcohol fiber and rayon fiber was used.

  After the injection, the gelled negative electrode 3 was filled inside the separator 4. The body of the negative electrode current collector 6 made of copper is inserted into a through hole provided in the center of the gasket 6 made of 6,6-nylon, and the head of the negative electrode current collector 6 is placed on the bottom plate made of a tin-plated steel plate. 7 to obtain an assembled sealing body 9. The opening of the battery case 1 was sealed with the assembly sealing body 9. At this time, the negative electrode current collector 6 was inserted into the gelled negative electrode 3, and the opening end portion of the battery case 1 was caulked to the peripheral portion of the bottom plate 7 through the outer peripheral portion of the gasket 5. Next, the exterior label 8 was coated on the outer surface of the battery case 1. In this way, an alkaline primary battery was produced. The KOH concentration in the total electrolyte in the produced alkaline primary battery was about 28% by weight, and the ZnO concentration was about 2.7% by weight.

At the time of producing the negative electrode, the KOH concentration and ZnO concentration of the electrolytic solution were made constant, and CsOH was added so that the CsOH concentration became a value shown in Table 1. Table 1 also shows the CsOH concentration of the total electrolyte in the produced battery.
In addition, about the density | concentration of each component (KOH, ZnO, and CsOH) in the total electrolyte solution in the produced battery, the negative electrode was taken out from the battery after 3 weeks from the production of the battery, as follows: The concentration of each component in the electrolyte solution in the negative electrode was measured.

The KOH concentration was determined by neutralization titration method. Specifically, the battery is disassembled, the battery from which the negative electrode current collector has been removed is set in a centrifuge, and the gel is formed in the negative electrode (in the hollow part of the positive electrode) by centrifugation (2000 rpm for 10 minutes). The product (gelator and negative electrode active material) was moved downward to separate it from the electrolyte. Thereafter, 200 μl of the electrolytic solution was collected with a micropipette so that the gel-like material was not mixed, and the volume was adjusted to 50 ml with pure water, and a phenolphthalein neutralization indicator was added to obtain a measurement solution. This measurement solution was subjected to neutralization titration with 0.1 mol / L hydrochloric acid.
The ZnO concentration was determined by chelate titration method. Specifically, about 5 ml of 0.1 mol / L hydrochloric acid was added to the solution subjected to neutralization titration to make it acidic, and then pure water was added to make a constant volume of 250 ml to obtain a sample solution. To 25 ml of this sample solution, 5 ml of an acetic acid-ammonium acetate solution and 3 drops of an XO chelate indicator were added to obtain a measurement solution. This measurement solution was subjected to chelate titration using a 0.01 mol / L EDTA solution.
The CsOH concentration was determined by ICP emission spectroscopy. Specifically, 10 ml was taken from the above sample solution, and pure water was added to make a constant volume of 20 ml to obtain a measurement solution. This measurement solution was subjected to ICP emission spectroscopic analysis using iCAP6300 manufactured by Thermo Fisher Scientific Co., Ltd.

<< Comparative Example 1 >>
An alkaline primary battery was produced in the same manner as in Example 1 except that an electrolytic solution without addition of CsOH was used instead of the electrolytic solution of Example 1 to which CsOH was added as an electrolytic solution for producing a negative electrode.

[Evaluation]
The following discharge tests were carried out for each battery of Example 1 and the battery of Comparative Example 1.
(1) Evaluation of low-load discharge characteristics Each alkaline battery was continuously discharged at 100 mA in an environment of 21 ° C. until the closed circuit voltage of the battery reached 0.9V. The continuous discharge time was determined and expressed as an index with the continuous discharge time of the battery of Comparative Example 1 as 100.

(2) Evaluation of medium load discharge characteristics Each alkaline battery was intermittently discharged in an environment of 21 ° C. until the closed circuit voltage of the battery reached 0.8V. In the intermittent discharge, a step of continuously discharging for 1 hour at 3.9Ω and then resting for 23 hours was repeated. The discharge time was determined and expressed as an index with the discharge time of the battery of Comparative Example 1 being 100. Here, the discharge time is a total value of the discharge time in each step.

(3) Evaluation of high-load discharge characteristics Each alkaline battery was intermittently discharged in DSC mode under a 21 ° C. environment until the closed circuit voltage of the battery reached 1.05V.
Specifically, a discharge step of discharging at 1500 mW for 2 seconds and then discharging at 650 mW for 28 seconds was repeated 10 times. After discharging for 5 minutes under these conditions, an intermittent discharge step of resting for 55 minutes was repeated. The number of discharges repeated until the closed circuit voltage of the battery reached 1.05 V was determined and expressed as an index with the number of discharges of Comparative Example 1 being 100. Here, the number of discharges is a number obtained by counting a discharge step of discharging at 1500 mW for 2 seconds and then discharging at 650 mW for 28 seconds as one, and the discharge step when the battery closing voltage reaches 1.05 V is Not included.
These evaluation results are shown in Table 1.

  As shown in Table 1, each battery of Example 1 in which CsOH was added to the electrolytic solution was good at any of low load, medium load, and high load as compared with the battery of Comparative Example 1 in which CsOH was not added. Discharge characteristics were obtained. Among the batteries of Example 1, no. In the batteries of 1-2, 1-3, 1-4, and 1-5, excellent medium load discharge characteristics were obtained.

Example 2
At the time of producing the negative electrode, RbOH was added so that the KOH concentration and ZnO concentration of the electrolytic solution were kept constant and the RbOH concentration became the value shown in Table 2. Except for the above, an alkaline primary battery was prepared and evaluated in the same manner as in Example 1. The concentration of RbOH in the total electrolyte solution in the produced battery was determined in the same manner as in the case of the CsOH concentration in Example 1.
The evaluation results are shown in Table 2. Table 2 also shows the results of Comparative Example 1 together with the batteries of Example 2.

  As shown in Table 2, each battery of Example 2 in which RbOH was added to the electrolyte solution was good at any of low load, medium load, and high load as compared with the battery of Comparative Example 1 without RbOH addition. Discharge characteristics were obtained. Among the batteries of Example 2, no. In the batteries of 2-2, 2-3, 2-4, and 2-5, particularly excellent medium load discharge characteristics were obtained.

Example 3
At the time of producing the negative electrode, CsOH and RbOH were added so that the KOH concentration and ZnO concentration of the electrolytic solution were constant and the CsOH concentration and RbOH concentration were as shown in Table 3. At this time, the CsOH concentration and the RbOH concentration were adjusted so that the total concentration of CsOH and RbOH in the electrolytic solution was 1% by weight. Except for the above, an alkaline primary battery was prepared and evaluated in the same manner as in Example 1.
The evaluation results are shown in Table 3. Table 3 also shows the results of Comparative Example 1 together with the batteries of Example 3.

  As shown in Table 3, in each battery of Example 3 in which CsOH and RbOH were added to the electrolytic solution, compared with the battery of Comparative Example 1 in which CsOH and RbOH were not added, low load, medium load, and high load In both cases, good discharge characteristics were obtained. Among the batteries of Example 3, no. In the batteries of 3-2 to 3-4, particularly excellent medium load discharge characteristics were obtained.

Example 4
An aqueous solution containing KOH and CsOH (concentration 2% by weight) was used as the electrolyte for preparing the negative electrode. The KOH concentration of the electrolyte for preparing the negative electrode and for pouring was changed to the values shown in Table 4. Except for the above, an alkaline primary battery was prepared and evaluated in the same manner as in Example 1.
The evaluation results are shown in Table 4.

  As shown in Table 4, the KOH concentration was 29 to 37% by weight. In the batteries of 4-2 to 4-6, good discharge characteristics were obtained at any of low load, medium load and high load. Among these, No. whose KOH concentration is 31 to 35% by weight. In the batteries of 4-3 to 4-5, excellent medium load discharge characteristics were obtained.

  The alkaline primary battery of the present invention is suitably used as a power source for electronic devices such as portable devices.

DESCRIPTION OF SYMBOLS 1 Battery case 2 Positive electrode 3 Gel-like negative electrode 4 Separator 5 Gasket 6 Negative electrode collector 7 Bottom plate 8 Exterior label 9 Assembly sealing body

Claims (8)

A positive electrode comprising manganese dioxide as a positive electrode active material and graphite as a conductive agent;
A negative electrode containing zinc or a zinc alloy as a negative electrode active material,
A separator disposed between the positive electrode and the negative electrode, and an alkaline primary battery comprising an electrolyte solution,
The electrolyte, Ri aqueous der containing at least one of CsOH and RbOH as KOH, and additives,
The alkaline primary battery in which the concentration of the additive in the electrolytic solution is 0.1 to 2% by mass . The alkaline primary battery according to claim 1 , wherein the KOH concentration in the electrolytic solution is 25 to 36 mass %. The alkaline primary battery according to claim 1, wherein when the additive is CsOH, the concentration of the additive in the electrolytic solution is 0.5 to 2 mass%. The alkaline primary battery according to claim 1, wherein when the electrolytic solution contains both CsOH and RbOH as the additive, the mass ratio of CsOH to RbOH is 20:80 to 80:20. (1) A step of obtaining a first electrolytic solution comprising an aqueous solution containing KOH and at least one of CsOH and RbOH as an additive,
(2) A step of obtaining a negative electrode by mixing zinc or a zinc alloy that is a negative electrode active material, a gelling agent, and the first electrolytic solution obtained in the step (1),
(3) A step of obtaining a hollow cylindrical positive electrode containing manganese dioxide as a positive electrode active material, graphite as a conductive agent, and a second electrolytic solution,
(4) a step of arranging the positive electrode in a battery case;
(5) the separator is disposed on the inner surface of the hollow portion of the positive electrode, after pouring the third electrolyte to the separator, the step of filling the positive electrode wherein through the separator into the hollow portion negative electrode of the well, ( 6) A step of arranging a sealing member in the opening of the battery case to obtain an alkaline primary battery ,
Only including,
The manufacturing method of an alkaline primary battery whose density | concentration of the said additive in the total electrolyte solution contained in the said alkaline primary battery is 0.1-2 mass% . The method for producing an alkaline primary battery according to claim 5 , wherein the concentration of the additive in the first electrolytic solution in the step (1) is 0.2 to 4% by mass . The method for producing an alkaline primary battery according to claim 5 , wherein the KOH concentration in the first electrolytic solution in the step (1) is 29 to 37 % by mass . The method for producing an alkaline primary battery according to claim 5 , wherein the KOH concentration in the third electrolytic solution in the step (5) is 29 to 37 % by mass .

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