JP2003017081A - Alkaline dry battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an alkaline dry battery with a large discharging capacity, capable of preventing drop in heavy-load characteristics even if the content of graphite in a positive mix is reduced. SOLUTION: This alkaline dry battery has a cylindrical positive can with a bottom also acting as a positive terminal and a container; and a gelled zinc negative electrode filled in a hollow part of the positive mix through a cylindrical separator with a bottom, and the positive mix is formed by adding a carbon base conductive material and polyolefin to a positive active material composed of nickel oxyhydroxide coated with a cobalt compound or a mixture of nickel oxyhydroxide coated with a cobalt compound and manganese dioxide. A conductive film mainly comprising graphite is formed in a part in contact with the positive mix of the positive can, and the area where the conductive film is formed is set to 75-90% of the area in contact with the positive mix of the inner surface of the positive can.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alkaline dry battery having excellent performance suitable for recent ultra heavy load and heavy load applications.

[0002]

[Conventional branch surgery] Notebook computer, CD player, M
Portable AV equipment such as D players and liquid crystal televisions, and ultra-heavy and heavy-load applications such as mobile phones have recently been required for alkaline dry batteries. In order to take out a large current for a long time, it is necessary to suppress the voltage drop at the time of discharging a large current. It is said that the voltage drop accompanying the discharge of the positive electrode largely depends on (1) the proton diffusivity of the manganese dioxide itself and (2) the diffusivity of the reactant in the positive electrode. In order to improve these points, the basic physical properties of electrolytic manganese dioxide have been conventionally investigated, and attempts have been made to improve the production method thereof. Further, increasing the surface area of manganese dioxide in the positive electrode contributes to the diffusivity of the reaction substance, and therefore, reduction in particle size of electrolytic manganese dioxide is being studied, and further improvement of filling property is being studied.

Further, in order to realize high performance in alkaline dry batteries, increasing the manganese dioxide content in the positive electrode mixture has also been studied. However, increasing the content of manganese dioxide inevitably reduces the content of the graphite powder of the conductive material contained in the positive electrode mixture. As a result, the formability and conductivity of the positive electrode mixture are lowered and the contact resistance with the positive electrode can is increased, which causes a reduction in short-circuit current and a reduction in heavy load characteristics. As a countermeasure against this, a conductive coating is formed on the inner surface of the positive electrode can, but at present, the reduction of the graphite content has reached the limit.

As described above, in spite of these conventional improvements, the present condition is that the current demands for improving the characteristics of alkaline dry batteries have not been sufficiently met.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems of alkaline dry batteries. Even if the content of graphite contained in the positive electrode mixture in the alkaline dry batteries is decreased, the heavy load characteristics are not improved. It is intended to realize an alkaline dry battery with a high discharge capacity that does not decrease.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a bottomed cylindrical positive electrode can that also serves as a positive electrode terminal and a container, a hollow cylindrical positive electrode mixture disposed in the positive electrode can, and a bottomed cylindrical separator. In the alkaline dry battery including a gelled zinc negative electrode filled in the hollow portion of the positive electrode mixture, the positive electrode mixture is nickel oxyhydroxide coated with a cobalt compound or oxywater coated with a cobalt compound. A positive electrode active material comprising a mixture of nickel oxide and manganese dioxide mixed with a polyolefin, and a conductive film containing graphite as a main component is formed in a portion of the positive electrode can in contact with the positive electrode mixture, The area where the film is formed is 75% of the area of the inner surface of the positive electrode can which contacts the positive electrode mixture.
It is an alkaline dry battery characterized by being -90%.

In the present invention, the compounding ratio of nickel oxyhydroxide coated with a cobalt compound and manganese dioxide in the positive electrode mixture is 50 to 100.
% By mass: 50 to 0% by mass, and the amount of the polyolefin added is 500 to 30,000 ppm, preferably 500 to 10,000 ppm, and more preferably 500 to 5,000 ppm, based on the positive electrode active material.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIG. 1 showing a cross section of an AA battery to which the present invention is applied.

In FIG. 1, reference numeral 1 denotes a bottomed cylindrical positive electrode can that also serves as a positive electrode terminal. In the present invention, a conductive coating film containing graphite as a main component is applied to the inner surface thereof. Then, the positive electrode mixture 2 is formed in a cylindrical shape and accommodated in the positive electrode can. And, in the hollow portion of this positive electrode mixture molded body,
A bottomed cylindrical separator 3 made of synthetic fiber nonwoven fabric such as vinylon is arranged. A gelled zinc negative electrode 4 is filled inside the separator 3, and a brass negative electrode current collector rod 5 is arranged so as to be partially embedded in the gelled zinc negative electrode 4. An insulating gasket 6 made of polyamide resin or the like is arranged in the opening of the positive electrode can 1,
The positive electrode 1 and the negative electrode 5 are separated from each other so that they do not come into contact with each other to cause a short circuit. The negative electrode current collector rod 5 is fixedly supported by a ring-shaped metal plate 7, a metal sealing plate 8 is arranged on the ring-shaped metal plate 7, and the positive electrode can 1 is caulked and sealed to form a dry battery.

The battery of the present invention will be described in detail below for each element of the dry battery. (Positive Electrode Mixture) In the present invention, the positive electrode mixture is composed of the above positive electrode active material, a carbon-based conductive material as a conductivity-imparting agent, and polyolefin as a binder. The mixing ratio of these components is 100: 10 to 15: 0.05 to 3 in terms of mass ratio of positive electrode mixture: carbon-based conductive material: polyolefin.
Is preferred. If the amount of the carbon-based conductive material falls below this range, the conductivity will decrease and the electromotive force will decrease. on the other hand,
When the amount exceeds the above range, the amount of the positive electrode active material is limited, so that the discharge capacity decreases. Further, when the amount of the polyolefin is less than this range, the strength of the molded body is low and the yield is lowered during battery production. On the other hand, when the amount of the polyolefin exceeds this range, the amount of the positive electrode active material is limited, so that the discharge capacity decreases. Further, the moldability and the conductivity are improved by mixing the positive electrode mixture with the electrolytic solution at the time of molding the positive electrode mixture.

As the carbon-based conductive material used in the present invention, known carbon materials such as graphite and carbon black can be used, but graphite is particularly preferable. Further, in the present invention, polyolefin is used as a binder. In the present invention, the reason for adding the polyolefin is that when the amount of graphite in the positive electrode mixture is reduced, the binding property of the positive electrode mixture is reduced, and the shape retention of the positive electrode mixture is prevented from decreasing. The positive electrode mixture component can be bound in a smaller amount than graphite. In the present invention, examples of the polyolefin include polyethylene and polypropylene.
These polyolefins are added to the positive electrode mixture in the form of particles. The average particle size is preferably in the range of approximately 10 to 1000 μm.

(Positive Electrode Active Material) As the positive electrode active material of the present invention, as described above, nickel oxyhydroxide coated with a cobalt compound is used alone or mixed with manganese dioxide. In the present invention, the mixing ratio of the cobalt compound-coated nickel oxyhydroxide and manganese dioxide is preferably in the range of 50 to 100% by mass: 50 to 0% by mass. If the content of cobalt compound-coated nickel oxyhydroxide is less than this, the desired discharge characteristics cannot be obtained.

(Nickel Oxyhydroxide) The nickel oxyhydroxide particles coated with the cobalt compound used in the present invention are nickel oxyhydroxide whose surface is coated with a cobalt compound, particularly a higher cobalt oxide. The nickel oxyhydroxide used in the present invention is preferably one having an endothermic peak in the range of 200 to 260 ° C. by differential thermal analysis. Further, the specific resistance of the nickel oxyhydroxide particles is preferably 100 Ω · cm or less. Furthermore, it is preferable that the nickel oxyhydroxide particles contain γ-nickel oxyhydroxide.

The reason why the nickel oxyhydroxide of the present invention is selected is based on the following knowledge. That is, the structure or configuration of the positive electrode mainly composed of the nickel oxyhydroxide particles, the electrode or the battery characteristics, as a result of earnestly proceeded, as a result, nickel oxyhydroxide particles whose surface is coated with a higher cobalt compound, 200 to 260 ° C. in differential thermal analysis (DTA)
It was confirmed that when it showed an endothermic peak in the range, it exhibited an excellent discharge capacity. That is, when the endothermic peak exceeds 260 ° C. or is less than 200 ° C., the discharge capacity is small and high activity is lost, and the endothermic peak is 20
It has been found that when it is in the range of 0 to 260 ° C, it has excellent high rate discharge characteristics.

The nickel oxyhydroxide particles whose surface is coated with a high-order cobalt compound and has an endothermic peak in the range of 200 to 260 ° C. in differential thermal analysis have a specific resistance of 100 Ω · cm or less, preferably 30 Ω.・ When it is not more than cm, excellent high rate discharge characteristics are exhibited. Here, when the specific resistance exceeds 100 Ω · cm, it is considered that the high-order cobalt compound coating the surface contains a large amount of electrochemically slightly inactive Co ₃ O ₄ or the like.

Further, nickel oxyhydroxide particles whose surface is coated with a higher order cobalt compound and have an endothermic peak in the range of 200 to 260 ° C. in differential thermal analysis are generally β-nickel oxyhydroxide and γ. -Nickel oxyhydroxide system is preferred. Here, γ-nickel oxyhydroxide has a higher valence and a higher oxygen overvoltage than β-nickel oxyhydroxide, but on the other hand, since it causes a decrease in bulk density, the active material Insufficient battery capacity will be obtained due to insufficient filling amount. Although β-nickel oxyhydroxide has a low oxygen overvoltage and has a problem of capacity deterioration due to self-discharge, coexistence with γ-nickel oxyhydroxide improves the problem of self-discharge.

The nickel oxyhydroxide particles may be single nickel oxyhydroxide or nickel oxyhydroxide whose surface is coated with higher order cobalt. Further, these nickel oxyhydroxides may contain at least one of zinc and cobalt. Incidentally, the nickel oxyhydroxide particles whose surface is coated with a high-order cobalt compound are, for example, nickel hydroxide particles coated with a high-order cobalt compound, which are treated with an oxidizing agent such as hydrogen peroxide or hypochlorite. It is obtained by immersion in an aqueous solution with stirring and chemical oxidation.

(Production Method of Nickel Oxyhydroxide) First, powder (particles) containing nickel hydroxide as a main component, metallic cobalt, cobalt hydroxide, and tricobalt tetroxide (Co).
A mixed powder with one or more powders of ₃ O ₄ ) and cobalt oxide (CoO) is prepared. Here, the addition composition ratio of cobalt or a cobalt compound is generally about 0.5 to 20% by mass in order to provide required conductivity and ensure discharge capacity.

Next, the above-mentioned mixed powder is put into a stirrable container, and an alkaline aqueous solution is added to this stirring system while stirring the mixed powder to make a uniform mixing system. At this time, the stirring / mixing system is heated (preferably a temperature of about 35 to 160 ° C.) in a state where oxygen coexists. During this heating / stirring / mixing process, cobalt or part of the cobalt compound dissolves in the alkaline aqueous solution as complex ions to form higher cobalt oxide containing alkali and then coats the surface of the nickel hydroxide particles. In this state, the particles are distributed among the particles to form a precursor of the conductive matrix.

As the alkali aqueous solution, sodium hydroxide aqueous solution is generally used, but a mixed system of sodium hydroxide aqueous solution and potassium hydroxide aqueous solution or lithium hydroxide aqueous solution may be used. And the alkali concentration is
In order to smoothly proceed the complex ionization or to easily form the required conductive matrix, 1 to 14N
A degree is preferable.

The heating means is not particularly limited, but microwave is effective in terms of improving utilization efficiency of the active material. That is, when microwaves are used as a heating source, water molecules in the mixing / stirring system are vibrated, and powder components such as nickel hydroxide particles are uniformly heated. Therefore, a conductive matrix is formed on the nickel hydroxide particle surfaces. It is formed uniformly. Furthermore, when microwaves are used as the heating source, the microwave energy input tends to cause defects in the crystal structure of the nickel hydroxide particles or change the state of the pores, increasing surface activity. Is recognized. When using a microwave as a heating source, it is preferable to set the microwave irradiation for about 20 minutes.

Next, 100 parts by mass of nickel hydroxide particles having the surface coated with a higher oxide of cobalt and 10 mo
500 parts by mass of 1 / l sodium hydroxide aqueous solution, 12
500 parts by mass of a mass% sodium hypochlorite aqueous solution is mixed, and the mixture is heated and stirred at a temperature of 80 ° C. This heating
After stirring, the resulting precipitate is washed and dried to prepare a nickel oxyhydroxide particle positive electrode active material whose surface is coated with higher cobalt.

(Production of Positive Electrode Mixture) Graphite powder and polyolefin particles are added to the nickel oxyhydroxide particles whose surface is coated with higher cobalt obtained by the above production means, and the mixture is stirred and mixed. Then, add potassium hydroxide aqueous solution,
The mixture is obtained by mixing in a general-purpose mixing container. Next, this mixture is pressure-molded into a hollow cylindrical shape having an outer diameter of 13.3 mm, an inner diameter of 9.0 mm, and a height (length) of 13.7 mm to prepare a positive electrode material mixture pellet.

(Negative Electrode) As the negative electrode of the present invention, a commonly used gel zinc negative electrode can be used. That is, zinc or its alloy powder is mixed with a gelling agent such as polyacrylic acid, dispersed in an electrolytic solution such as an aqueous solution of potassium hydroxide, and gelled.

(Preparation of Negative Electrode) Average particle size 10 including alloy components of zinc such as indium, bismuth and aluminum
Add polyacrylic acid (gelling agent) to zinc alloy powder of 0 to 300 μm, stir and mix for 5 minutes in a general-purpose mixing container,
A homogeneous mixed system is obtained. On the other hand, tetrabutylammonium hydroxide is added to an aqueous potassium hydroxide solution in which zinc oxide is dissolved, and the mixture is stirred and mixed for 10 minutes to sufficiently disperse it. Then, to this dispersion, the zinc alloy powder-based mixture was gradually added over 4 minutes, and at the same time, 200 × 10 ⁵ Pa was added.
By stirring and mixing under a reduced pressure of (150 mmHg) or less, and further stirring for 5 minutes under a reduced pressure of 13.3 × 10 ⁵ Pa (10 mmHg) or less, a gelled negative electrode having a uniform composition system is produced. It

(Positive Electrode Can) In the present invention, even if the content of graphite in the positive electrode mixture is reduced by forming a conductive coating film containing graphite powder on the inner surface of the positive electrode can,
By forming the conductive coating on the inner surface of the positive electrode can, the contact resistance between the positive electrode mixture and the positive electrode can can be reduced and the discharge capacity can be improved. However, the area of this conductive coating needs to be 75 to 90% of the area of the portion of the inner surface of the positive electrode can which contacts the positive electrode mixture. If the area of the conductive coating is less than 75%, the intended purpose is not sufficiently achieved, and if it is more than 90%, the filling mixture is lifted during battery production. FIG. 2 is a perspective view of a main part of the battery of the present invention. In the figure, 20 is a positive electrode can,
Reference numeral 21 is a conductive coating applied to the inner surface of the positive electrode can. The method of applying the conductive coating is to dilute a conductive coating material containing graphite powder as a main component with a low boiling point organic solvent such as methyl ethyl ketone, and spray the composition on the inner surface of the positive electrode can with a spray gun. Do not coat the part of the positive electrode can opening that contacts the gasket. After applying the conductive paint with a spray gun, the solvent is evaporated with a dryer. The thickness of the remaining conductive film is 1 to
About 10 μm is desirable.

(Assembly of Battery) Next, using the positive electrode material mixture pellets prepared above and the gelled negative electrode, a single 3-type nickel whose schematic structure is shown in cross section in FIG. 1 is carried out by a conventional method. Assemble the zinc primary battery. In FIG. 1, 1
Is a bottomed cylindrical metal can (exterior can) that also doubles as a positive electrode terminal. In the hollow cylinder, three positive electrode mixture pellets are stacked and filled with the positive electrode mixture 2 that has been pressure-molded again. Has been done. Further, a bottomed cylindrical separator 3 made of acetalized polyvinyl alcohol fiber is mounted in the hollow portion of the positive electrode mixture 2, and a gelled negative electrode 4 is filled inside the separator 3.

In the gelled negative electrode 4, one end side of a brass negative electrode current collector rod 5 is inserted and arranged, and the outer peripheral surface of this negative electrode current collector rod 5 protruding from the gelled negative electrode 4 is at the other end side. , And a double annular insulating gasket 6 made of polyamide resin is arranged between the inner peripheral surface of the opening of the metal can 1. Further, a ring-shaped metal plate 7 is fitted and arranged between the double rings of the insulating gasket 6, and a hat-shaped metal sealing plate 8 also serving as a negative electrode terminal abuts on the tip of the negative electrode current collector rod 5. It is arranged. The opening edge of the metal can 1 is bent inward to seal the opening edge of the metal can 1 with the insulating gasket 6 and the metal sealing plate 8.

[0029]

EXAMPLES Examples of the present invention will be described in detail below. (Examples 1 to 3) First, powder (particles) containing nickel hydroxide as a main component, metallic cobalt, cobalt hydroxide, tricobalt tetroxide (Co ₃ O ₄ ) and cobalt oxide (Co).
A mixed powder with one or more powders of O) is prepared.
Here, the addition composition ratio of cobalt or a cobalt compound is generally about 0.5 to 20% by mass in order to provide required conductivity and ensure discharge capacity. Next, the mixed powder is put into a stirrable container, and an alkaline aqueous solution such as sodium hydroxide is added to the stirring system while stirring the mixed powder to make a uniform mixing system. At this time, the stirring / mixing system is heated (preferably at a temperature of about 35 to 160 ° C.) by irradiating with microwaves for about 20 minutes in the presence of oxygen. In this heating / stirring / mixing process, cobalt or a part of the cobalt compound is dissolved in the alkaline aqueous solution as complex ions to form higher-order cobalt oxide containing alkali,
The nickel hydroxide particles are distributed among the particles in a state of covering the surface of the particles to form a precursor of the conductive matrix. Next, 100 parts by mass of nickel hydroxide particles having the surface coated with a cobalt high-order oxide, 500 parts by mass of a 10 mol / l sodium hydroxide aqueous solution, and 500 parts by mass of a 12% by mass aqueous sodium hypochlorite solution. Mix with and 80 ℃
Heat and stir at the temperature. After the heating and stirring, the obtained precipitate is washed and dried to prepare a positive electrode active material of nickel oxyhydroxide particles whose surface is coated with higher cobalt.

A positive electrode mixture containing nickel oxyhydroxide coated with a cobalt compound prepared by the above method was prepared, and the JIS standard LR6 type (AA) shown in FIG. 1 was prepared.
Shape) Assembled alkaline battery. In the figure, reference numeral 1 denotes a bottomed cylindrical positive electrode can that also serves as a positive electrode terminal, and a conductive coating containing graphite powder as a main component is formed on the inner surface by a coating method using a spray gun. The coating area of the conductive coating was 90% of the area of the inner surface of the positive electrode can which was in contact with the positive electrode mixture. The thickness of the conductive coating was 5 μm . In this positive electrode can, three positive electrode mixtures 2 which are pressure-molded in a cylindrical shape are separately filled. The positive electrode mixture 2 is 120 parts by mass of nickel oxyhydroxide coated with a cobalt compound, 10.5 parts by mass of graphite powder, and 0.12 of polyethylene.
Dry stirring with a positive electrode mixture composed of parts by mass for 10 minutes,
After performing the rotation at 300 rpm, an alkaline electrolyte solution was prepared.
Add 0 parts by mass, wet agitate for 10 minutes, and rotate at 300 r
It was performed at a rotational speed of 600 rpm for 10 minutes for the purpose of uniform mixing. Graphite powder content is 8wt%, polyethylene addition amount is 100
It was set to 0 ppm. Further, in the hollow portion of the positive electrode mixture 2, a bottomed cylindrical separator 3 made of a nonwoven fabric of vinylon and PVA fiber is arranged. The gelled zinc negative electrode 4 is filled through this separator. A negative electrode current collector rod 5 made of brass is mounted in the gelled negative electrode 4 with its tip inserted into the negative electroded gel 4. Negative electrode collector rod 5
An insulating gasket 6 made of a double-ring polyamide resin is provided on the outer periphery of the upper part of and the inner peripheral surface of the upper part of the positive electrode can 1. In addition, a ring-shaped metal plate 7 is arranged between the double annular portions of the insulating gasket 6, and a cap-shaped metal sealing plate 8 also serving as a negative electrode terminal is provided on the metal plate 7 on the head of the collector rod 5. It is arranged so as to abut. Then, the inside of the positive electrode can 1 is sealed by the gasket 6 and the metal sealing plate 8 by bending the opening edge of the positive electrode can 1 inward.

(Comparative Examples 1 to 9) As Comparative Examples in Table 1, it was carried out except that the content of nickel oxyhydroxide was less than 50% by mass and that no conductive coating was formed on the inner surface of the positive electrode can. An LR6 type alkaline dry battery was assembled in the same manner as in Examples 1 to 3. Also, an LR6 type alkaline dry battery was assembled in the same manner as in Examples 1 and 3 except that nickel oxyhydroxide was used.

Each LR6 type alkaline dry battery assembled as described above was examined for discharge capacity at 20 ° C. after storage at 60 ° C. for 0 days and 20 days, and the results are shown in Table 1. The discharge capacity was 1500 mA continuous discharge test for 10 batteries, and the final voltage was 0.9.
The average value of the duration (min.) Until V was shown.

[0033]

[Table 1]

As is clear from Table 1, the battery containing nickel oxyhydroxide coated with a cobalt compound had an improved discharge capacity as compared with the battery containing only manganese dioxide. However, when there was no conductive coating on the inner surface of the positive electrode can, no improvement in discharge capacity was observed. The battery containing nickel oxyhydroxide showed an improvement in discharge capacity, but the discharge after storage was poor. This is due to the self-discharge of nickel oxyhydroxide. The amount of nickel oxyhydroxide coated with cobalt compound is 50
If it is less than%, the discharge capacity is improved in the first stage, but the discharge after storage is not good. From this result, it was found that the compounding amount of the cobalt compound-coated nickel oxyhydroxide was effective at 50% by mass or more.

(Example 4 and Comparative Examples 10 and 11) A battery equivalent to that of Example 1 was prepared, except that the area of graphite applied to the inner surface of the positive electrode can was changed as shown in Table 2. The battery characteristics of the obtained battery were measured in the same manner as in the above example. The results are also shown in Table 2.

[0036]

[Table 2]

In Table 2 above, the floating of the filling mixture was determined by measuring the filling depth from the opening of the positive electrode can to the positive electrode mixture. As is clear from the results in Table 2 above,
If the area of the conductive coating is more than 90% of the area of the inner surface of the can which is in contact with the positive electrode mixture, the filling mixture may be lifted, resulting in defective application of the sealant, defective bead processing, etc. The problem occurs. On the other hand, when the content is less than 70%, the problem of deterioration of storage characteristics occurs, and it was found that each is not preferable.

[0038]

As described above, according to the present invention,
It was possible to realize an alkaline dry battery having a high discharge capacity, excellent heavy load characteristics, and excellent storage characteristics.

[Brief description of drawings]

FIG. 1 is a sectional view of a JIS standard LR6 type (AA) alkaline dry battery manufactured according to the present invention.

FIG. 2 is a perspective view of the inner surface of the positive electrode can in the embodiment of the present invention.

[Explanation of symbols]

1 ... Positive electrode can 2 ... Positive electrode mixture 3 ... Separator 4 ... Gel zinc negative electrode 5: Negative electrode collector rod 6 ... Insulation gasket 7 ... Ring-shaped metal plate 8: Metal sealing plate 9 ... Conductive coating layer containing graphite powder as a main component 20 ... Positive electrode can 21 ... Conductive film

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5H024 AA02 AA03 AA14 BB07 BB08                       CC02 DD02 DD09 DD17 EE03                       EE09 GG01 HH01 HH15                 5H050 AA02 BA04 CA03 CA05 CB13                       DA02 DA10 DA11 DA17 EA08                       EA09 EA23 FA07 FA18 GA22                       HA01 HA12

Claims (4)

[Claims] 1. A positive electrode can, which has a bottomed cylindrical shape and serves as a positive electrode terminal and a container, a hollow cylindrical positive electrode mixture disposed in the positive electrode can, and a positive electrode mixture having a bottomed cylindrical separator. In an alkaline dry battery comprising a gelled zinc negative electrode filled in the hollow part of the above, the positive electrode mixture is nickel oxyhydroxide coated with a cobalt compound, or a mixture of nickel oxyhydroxide coated with a cobalt compound and manganese dioxide. An alkaline dry battery characterized by comprising a positive electrode active material composed of (1) and a carbon conductive material and a polyolefin. 2. A conductive film containing graphite as a main component is formed in a portion of the positive electrode can which contacts the positive electrode mixture, and an area where the conductive film is formed is a portion of the inner surface of the positive electrode can which contacts the positive electrode mixture. The alkaline dry battery according to claim 1, which has an area of 75 to 90%. 3. The compounding ratio of nickel oxyhydroxide coated with a cobalt compound and manganese dioxide in the positive electrode mixture is 50 to 100% by mass: 50 to 0% by mass, and the amount of polyolefin added is positive electrode active. 50 for substance
It is 0-30000ppm, It is characterized by the above-mentioned.
Alkaline battery described. 4. The alkaline dry battery according to any one of claims 1 to 3, wherein the polyolefin is polyethylene, and the addition amount thereof is 500 to 30,000 ppm.