JP2003338292A - Alkaline battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an alkaline battery which suppresses leakage of an electrolytic solution to the outside caused by the creep of the electrolytic solution in a separator and enhances its resistance to liquid leakage. <P>SOLUTION: In an alkaline battery using β-type nickel oxyhydroxide as a positive electrode active material and having a positive electrode mix 12 molded in a shape of a hollow cylinder and a negative electrode mix 14 which makes zinc a main negative electrode active material in the central part of the alkaline battery 100 through a cylindrical type separator 13 with a bottom, a PTFE (polytetrafluoroethglene) is coated as a water repellent agent at a predetermined range of an opening edge of the separator 13, e.g. within 2 to 10 mm from the opening edge. Accordingly, the leakage of the electrolytic solution to the outside caused by creep-up of the electrolytic solution in the separator 13 is suppressed and the resistance to liquid leakage characteristic when a safety valve 17a is cleaved or a closing member 17 is cracked is enhanced. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an alkaline battery. Specifically, a hollow cylindrical positive electrode mixture is placed in a bottomed cylindrical metal positive electrode can, and an alkaline aqueous solution as an electrolytic solution is contained in the center of the positive electrode mixture through a bottomed cylindrical separator. Leakage prevention that prevents the electrolyte from leaking from the sealing member through the separator on the open end side of the separator in an alkaline battery in which a gel negative electrode mixture is placed and the metal positive electrode can is sealed with the sealing member. By providing the means, it is possible to suppress the leakage of the electrolytic solution to the outside due to the creeping-up of the electrolytic solution in the separator, and to improve the leakage resistance property of the alkaline battery.

[0002]

2. Description of the Related Art In recent years, with the development of portable electronic devices, a large amount of current can be taken out as a power source battery thereof.
Moreover, there is an increasing demand for high-capacity batteries that can be used for a longer period of time. Therefore, the demand for cylindrical alkaline batteries, which have excellent filling characteristics and large discharge capacity, is increasing.

FIG. 9 shows the structure of a cylindrical alkaline battery 1. The cylindrical alkaline battery 1 shown in FIG. 9 is LR6.
It has a (AA type) inside-out type structure.

The alkaline battery 1 comprises a positive electrode can 11, a positive electrode mixture 12, a separator 13, a negative electrode mixture 14, and a sealing unit 20. Sealing unit 2
Reference numeral 0 is composed of a negative electrode collector pin 15, a negative electrode terminal plate 16, a sealing member 17, and a reinforcing member 18.

The positive electrode can 11 is formed by pressing a metal plate plated with nickel, for example. The positive electrode can 11 also serves as the positive electrode terminal 11 a of the alkaline battery 1. A conductive paint for increasing the contact conductivity with the positive electrode mixture 12 is applied to the inner surface of the positive electrode can 11 to form a conductive coating layer (not shown).

The positive electrode mixture 12 has a hollow cylindrical shape as shown in FIG. 9, and is arranged inside the positive electrode can 11. The positive electrode mixture 12 is formed by mixing beta-type nickel oxyhydroxide (or manganese dioxide) as a positive electrode active material, carbon powder as a conductive agent, and an alkaline aqueous solution as an electrolytic solution, and molding the mixture into a hollow cylindrical shape. Is. Graphite powder is used as the carbon powder used as the conductive agent. As the alkaline aqueous solution, for example, an aqueous potassium hydroxide solution is used, but an aqueous solution of lithium hydroxide, sodium hydroxide or the like or a mixture thereof can also be used.

The positive electrode mixture 12 is manufactured as follows. First, beta-type nickel oxyhydroxide, graphite, and an aqueous potassium hydroxide solution are weighed at a predetermined weight ratio and mixed by a stirring method such as an impeller or a ball mill. Next, the mixed material is press-molded to produce a hollow cylindrical pellet (hollow cylindrical member). A predetermined number, three in this example, of the hollow cylindrical pellets are inserted into the positive electrode can 11 to form the positive electrode mixture 12.

The separator 13 is interposed between the positive electrode mixture 12 and the negative electrode mixture 14 to hold the electrolytic solution and to separate the two electrodes from each other. As the separator 13, an alkali-resistant synthetic fiber non-woven fabric, for example, a non-woven fabric made of vinylon (trade name), polyamide, polyolefin, or cellulose is used, and has a bottomed cylindrical shape, and is inside the positive electrode mixture 12. Will be distributed to.

The negative electrode mixture 14 is in the form of gel and is filled in the separator 13. The negative electrode mixture 14 is obtained by uniformly dispersing and mixing granular zinc and zinc oxide, which are negative electrode active materials, in an aqueous solution of potassium hydroxide, which is an electrolytic solution, using a gelling agent.

Further, the sealing unit 20 of the nickel-hydrogen battery 100 comprises a brass negative electrode collector pin 15, a negative electrode terminal plate 16, a nylon sealing member 17, and a reinforcing member 1.
8 and. A negative electrode collector pin 15 made of, for example, brass is welded to the negative electrode terminal plate 16. The sealing unit 20 functions to seal the opening of the positive electrode can 11.

The alkaline battery 1 shown in FIG. 9 is manufactured as follows. First, the positive electrode mixture 12 pressure-molded into a hollow cylinder is inserted into the positive electrode can 11. Next, the bottomed cylindrical separator 13 is inserted into the center of the positive electrode mixture 12, and the separator 13 is filled with the gel negative electrode mixture 14. Finally, the sealing unit 20 is inserted into the positive electrode can 11, the edge portion of the opening of the positive electrode can 11 is bent inside, and the sealing unit 20 is fixed. When the sealing unit 20 is inserted into the positive electrode can 11, the negative electrode current collector pin 15 welded to the negative electrode terminal plate 16 is inserted into the gelled negative electrode mixture 14.

In the alkaline battery 1, the current collection of the negative electrode is
The negative electrode collector pin 15 welded to the negative electrode terminal plate 16 is secured by being inserted into the negative electrode mixture 14. The current collection of the positive electrode is ensured by connecting the positive electrode mixture 12 and the positive electrode can 11. The outer peripheral surface of the positive electrode can 11 is
It is covered with an outer label 19 on which the manufacturer's name, battery type, precautionary notes, etc. are written, and the positive electrode terminal 11 a is located on the convex portion on the bottom of the positive electrode can 11.

The alkaline battery 1 thus formed is
It has a completely sealed structure. Therefore, if the battery is stored for a long time, charged by plus / minus reverse loading, or over-discharged or short-circuited due to a mix of old and new batteries, the internal pressure may increase abnormally due to gas generation or heat generation, and in some cases Liquid leakage or rupture (such as destruction of the sealing member by gas) may occur. Therefore, a thin portion (safety valve) 17a is provided in a part of the sealing member 17 so as to prevent the battery from bursting even when it is misused, so as to be broken when the internal pressure rises. According to this
When hydrogen is generated inside the battery during storage of the battery or misuse, the internal pressure increases and the safety valve 17a is opened to prevent the battery from bursting.

[0014]

However, when hydrogen is generated inside the battery during storage of the battery or during misuse and the internal pressure increases and the safety valve 17a is opened, the electrolysis is caused by the characteristic creeping phenomenon of the alkaline electrolyte. There is a problem that the liquid leaks to the outside of the battery through the cleavage portion through the separator 13.

Further, there is a case where the sealing member is deteriorated by absorbing water or permeating hydrogen gas during storage of the battery. In this case, cracks occur in the sealing member,
There is a problem that the electrolytic solution in the battery leaks to the outside of the battery through the separator 13.

As measures against this leakage, a substance having a high hydrogen overvoltage is added to suppress the generation of hydrogen gas, the sealing member is improved to adjust the cleaving pressure of the safety valve 17a, and the amount of electrolyte used is regulated. , Reduce the amount of free electrolyte in the battery. Further, as measures against the creeping phenomenon, in addition to increasing the viscosity of the alkaline solution, the concentration of the alkaline solution is decreased, or a sodium hydroxide (NaOH) solution having excellent leakage resistance is used as the electrolytic solution. However, sufficient leakage resistance cannot be obtained by these measures against leakage.

Therefore, an object of the present invention is to provide an alkaline battery capable of suppressing leakage of the electrolytic solution to the outside due to the creeping-up of the electrolytic solution in the separator and improving the leakage resistance.

[0018]

In the alkaline battery according to the present invention, a hollow cylindrical positive electrode material mixture is placed in a metal positive electrode can having a bottomed cylindrical shape, and a bottomed cylinder material is placed in the center of the positive electrode material mixture. A gelled negative electrode mixture containing an alkaline aqueous solution as an electrolytic solution is placed through a separator, and in an alkaline battery in which a positive electrode can is sealed with a sealing member, on the opening end side of the separator, the electrolytic solution passes through the separator. A leak preventing means for preventing the leak from the sealing member is provided.

The leak preventing means is made of, for example, water repellent in a predetermined area of the opening end of the separator. Also, for example,
It is a plastic film provided between the opening end of the separator and the sealing member.

In the present invention, a leak preventing means for preventing the electrolyte from leaking from the sealing member through the separator is provided on the open end side of the separator. For example, a range of a predetermined length from the open end of the separator is provided. Is coated with a water repellent, or a plastic film is provided between the opening end of the separator and the sealing member. The application range of the water repellent is
For example, the distance is 2 to 10 mm from the opening end of the separator. The water repellent is, for example, F in the dispersion state.
EP (Fluorinated ethylene propylene), PTFE
(Polytetrafluoroethylene) Fluororesin, Fluorinated oil, Asphalt, or Paraffin
affin). For the plastic film, for example, one of nylon, polypropylene or polyethylene is used. The thickness is, for example, 0.1 mm or less.

As a result, when hydrogen is generated inside the battery during storage of the battery or during misuse, the internal pressure increases and the safety valve opens, or when the sealing member cracks due to deterioration, the electrolyte crawls in the separator. Leakage of the electrolytic solution to the outside due to rising can be suppressed, and the leakage resistance property is improved.

Further, as the positive electrode active material, beta-type nickel oxyhydroxide having spherical (including substantially spherical) particles having an average particle diameter within a predetermined range, or the beta-nickel oxyhydroxide having a predetermined average particle diameter is predetermined. By using manganese dioxide in the range, it becomes possible to obtain an alkaline battery having excellent heavy load discharge characteristics.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION An alkaline battery 100 according to a first embodiment of the present invention will be described below. FIG. 1 shows the configuration of an alkaline battery 100 according to the first embodiment. The alkaline battery 100 is an AA nickel-zinc battery having an inside-out structure. Further, in FIG. 1, parts corresponding to those in FIG. 9 are shown with the same reference numerals.

As shown in FIG. 1, this alkaline battery 10
0 is a positive electrode can 11, a positive electrode mixture 12, a separator 13
And a negative electrode mixture 14 and a sealing unit 20. The sealing unit 20 is composed of a negative electrode collector pin 15, a negative electrode terminal plate 16, a sealing member 17, and a reinforcing member 18.

The positive electrode can 11 is formed by pressing a metal plate plated with nickel, for example. The positive electrode can 11 also serves as the positive electrode terminal 11a of the alkaline battery 100. A conductive paint for increasing the contact conductivity with the positive electrode mixture 12 is applied to the inner surface of the positive electrode can 11 to form a conductive coating layer (not shown). As the conductive paint, a paint containing graphite powder as a conductive agent and a binder is used.

The positive electrode mixture 12 has a hollow cylindrical shape as shown in FIG. 1, and is arranged inside the positive electrode can 11. The positive electrode mixture 12 is formed by mixing beta-type nickel oxyhydroxide (β-NiOOH) as a positive electrode active material, carbon powder as a conductive agent, and an alkaline aqueous solution as an electrolyte, and molding the mixture into a hollow cylindrical shape. is there. The beta-type nickel oxyhydroxide as the positive electrode active material is spherical (including substantially spherical) particles, and preferably has an average particle diameter of 5 to 50 μm.

There are many kinds of carbon powder used as a conductive agent, such as acetylene black, various carbon black modified products, and synthetic graphite powder, and the shapes thereof are various such as granular, scaly and fibrous. It is of course desirable that the conductivity is high, but the purity, the mixture moldability and the liquid retention property are further high. In this embodiment, graphite powder is used as the carbon powder used as the conductive agent.

As the alkaline aqueous solution, for example, an aqueous potassium hydroxide solution is used, but an aqueous solution of lithium hydroxide, sodium hydroxide or the like can also be used.

The positive electrode mixture 12 is manufactured as follows. First, beta-type nickel oxyhydroxide, graphite powder, and a potassium hydroxide aqueous solution having a concentration of 30 mass% are weighed at a weight ratio of 80:10:10 and mixed by a stirring method such as an impeller or a ball mill. Next, the mixed positive electrode mixture is press-molded to form hollow cylindrical pellets. A predetermined number, three in the present embodiment, of the hollow cylindrical pellets are inserted into the positive electrode can 11 to form a positive electrode.

As shown in FIG. 2, the separator 13 has a bottomed cylindrical shape, and is coated with a water repellent within a range of a predetermined length h from the open end 13a. The coating portion 21 of the separator 13 coated with the water repellent agent functions as a leak prevention unit. As the separator 13, an alkali-resistant synthetic fiber non-woven fabric, for example, non-woven fabric made of vinylon (trade name), polyamide, polyolefin, or cellulose is used. Further, as the water repellent, it is possible to use FEP, PTFE type fluororesin, fluorinated oil, asphalt, paraffin or the like in a dispersion state.

The negative electrode mixture 14 is in the form of gel and is filled in the separator 13. The negative electrode mixture 14 is obtained by uniformly dispersing and mixing granular zinc and zinc oxide, which are negative electrode active materials, in an aqueous solution of potassium hydroxide, which is an electrolytic solution, using a gelling agent. Zinc as the negative electrode active material is preferably granular powder. Moreover, starch, a cellulose derivative, polyacrylate, etc. can be used for a gelling agent.

Further, the sealing unit 20 of the alkaline battery 100 includes a negative electrode collector pin 15 made of brass and a negative electrode terminal plate 16.
And a sealing member 17 made of a nylon material and a reinforcing member 18. A negative electrode collector pin 15 made of, for example, brass is welded to the negative electrode terminal plate 16. The sealing unit 20 functions to seal the opening of the positive electrode can 11. Further, a part of the sealing member 17 is provided with a safety valve (thin portion) 17a so as to be broken when the internal pressure rises.

The alkaline battery 100 shown in FIG. 1 is manufactured as follows. First, three positive electrode mixtures 12 that are pressure-molded into a hollow cylinder are inserted into the positive electrode can 11. next,
A bottomed cylindrical separator 13 is inserted into the center of the positive electrode mixture 12, and a gel-like negative electrode mixture 14 is placed in the separator 13.
To fill. Finally, the sealing unit 20 is inserted into the positive electrode can 11, the edge portion of the opening of the positive electrode can 11 is bent inward,
The sealing unit 20 is fixed. When the sealing unit 20 is inserted into the positive electrode can 11, the negative electrode current collector pin 15 welded to the negative electrode terminal plate 16 is inserted into the gelled negative electrode mixture 14.

In the alkaline battery 100, the current collection of the negative electrode is ensured by inserting the negative electrode current collecting pin 15 welded to the negative electrode terminal plate 16 into the negative electrode mixture 14. The current collection of the positive electrode is ensured by connecting the positive electrode mixture 12 and the positive electrode can 11. The outer peripheral surface of the positive electrode can 11 is covered with an outer label 19 on which the manufacturer name, battery type, precautionary notes, etc. are written, and the positive electrode terminal 11 a is located on the convex portion on the bottom of the positive electrode can 11.

Here, the following alkaline batteries of Examples 1 to 6 and Comparative Example 1 were examined.

In Example 1, the LR6 type (AA type) size positive electrode can 11 was constructed by an iron plate having a nickel plated surface. A conductive coating material for increasing contact conductivity with the positive electrode mixture 12 is applied to the inner surface of the positive electrode can 11 to form a conductive coating layer. As the positive electrode mixture 12, beta-type nickel oxyhydroxide manufactured by a chemical oxidation method and having spherical particles was used. Beta-type nickel oxyhydroxide, graphite powder, and a potassium hydroxide aqueous solution having a concentration of 30 mass% were weighed at a weight ratio of 80:10:10,
Mix by stirring method such as impeller or ball mill, outer diameter 13.2mm, inner diameter 9mm, height 13.4m
m into a hollow cylindrical pellet having a mass of 3 g,
Three of these were pressure-molded into a hollow cylinder and used.

The separator 13 has a bottomed cylindrical shape by winding a polyolefin nonwoven fabric into a cylindrical shape and bending the bottom portion inward. At the open end of this separator 13, PT
FE was applied to a length of 2 mm (see Figure 2).

The negative electrode mixture 14 was constituted by a gelled potassium hydroxide aqueous solution containing 65% by weight of granular zinc and 2% by weight of zinc oxide, and 5 g of this was filled.

Further, a hole having a diameter of 0.1 mm is specially formed in the sealing member 17 for an experiment for evaluating the leakage resistance property. It is assumed that the hole is formed in the sealing member 17 when the safety valve is opened or when the sealing member 17 is cracked.

Using the positive electrode can 11, the positive electrode mixture 12, the separator 13, the negative electrode mixture 14 and the sealing member 17 as described above, a battery was manufactured in accordance with the above-described alkaline battery manufacturing procedure.

In Examples 2 to 6, PTFE was applied to the open end of the separator 13 at 4 mm, 6 mm, 8 mm, 10 mm, 1
2 mm was applied. Except for this, batteries were produced in the same manner as in Example 1 and in accordance with the above-described alkaline battery 100 production procedure.

In the comparative example, an AA alkaline battery similar to that of the example was used, in which the open end of the separator 13 was not coated with PTFE. A battery was manufactured in the same manner as in Example 1 except for the above and following the procedure for manufacturing the alkaline battery 100 described above.

The alkaline battery 100 of the example and the alkaline battery of the comparative example thus produced were evaluated for leakage resistance, discharge characteristics and discharge capacity under the following test conditions.

The evaluation of the liquid leakage resistance was carried out by making 100 prototypes of each of the batteries shown in Examples and Comparative Examples and setting the batteries at room temperature for 20 minutes.
It was stored at a temperature of 70 ° C. and a humidity of 70%, and the time when the electrolytic solution came out was examined. The discharge characteristics were evaluated by discharging at a current of 400 mA until the battery voltage reached 0.9 V, and the discharge capacity at this time was examined.

FIG. 3 shows the evaluation results of the leakage resistance property. The evaluation results of the discharge characteristics are shown in Table 1 and FIG.

From the results shown in FIG. 3, it is clear that the longer the coating length, the better the liquid leakage resistance. In other words, it is considered that the moving distance of the electrolytic solution becomes longer and the liquid leakage becomes less likely.

[0047]

[Table 1]

From the measurement results shown in Table 1, the relationship curve between the coating range of the water repellent and the discharge capacity shown in FIG. 4 can be obtained. From FIG. 4, it was found that the discharge capacity decreases as the coating length increases. That is, when the coating length is increased, the reaction area of the positive electrode and the negative electrode is reduced, and the reaction efficiency is deteriorated.

As described above, in order to improve the liquid leakage resistance without deteriorating the discharge performance, it is desirable that the application range of the water repellent agent is set within 2 to 10 mm from the opening end of the separator 13.

Next, regarding the relationship between the particle size distribution of beta-type nickel oxyhydroxide and the discharge capacity, Example 101
~ 122 alkaline batteries 100 were investigated.

In Examples 101 to 122, the beta-type nickel oxyhydroxide used in the positive electrode mixture 3 was manufactured by a chemical oxidation method, and the shape of the particles was spherical, and the range of the average particle diameter of the particles was 1 Each battery was manufactured according to the procedure for manufacturing the alkaline zinc battery described above by using the one changed in the range of up to 70 μm. At this time, the range of the particle size distribution of the beta-type nickel oxyhydroxide was within a range of about ± 20 μm centering on the average particle size value. Moreover, what applied PTFE 4 mm was used for the opening end of the separator 13.

Examples 101 to 122 produced in this way
The discharge capacity of the alkaline battery 100 was evaluated under the following test conditions.

The discharge capacity was measured by alkaline battery 100.
As the discharge conditions, after the battery was manufactured, the discharge time until the discharge end voltage reached 1.0 V was measured by constant power discharge of 1.5 W in an atmosphere of 20 ° C. The results are shown in Table 2.

[0054]

[Table 2]

From the results shown in Table 2, the average particle size of the beta-type nickel oxyhydroxide particles, which increases the discharge time of the battery, is in the range of 5 to 50 μm. Therefore, when the average particle diameter of nickel oxyhydroxide exceeds 50 μm, the repulsive force between particles becomes strong when the positive electrode is pressure-molded, and it is difficult to fill a large amount of active material per battery. Therefore, the discharge time is short and the heavy load discharge characteristics are deteriorated. Also, when it is less than 5 μm, the discharge capacity becomes small, and the heavy load discharge characteristics are significantly deteriorated. Therefore, it is desirable to use beta-type nickel oxyhydroxide having an average particle size of 5 to 50 μm.

As described above, in the present embodiment, the hollow cylindrical positive electrode mixture 1 is placed in the bottomed cylindrical metal positive electrode can 11.
2 is arranged, the negative electrode mixture 14 is arranged in the central portion of the positive electrode mixture 12 via the bottomed cylindrical separator 13, and the metal positive electrode can 11 is sealed with the sealing member 17, By applying PTFE as a water repellent within 2 to 10 mm from the opening end of the separator 13, leakage of the electrolyte to the outside due to the creeping of the electrolyte in the separator 13 is suppressed, and the safety valve 17a is opened. The liquid leakage resistance when the sealing member 17 is cracked can be improved.

By using beta-type nickel oxyhydroxide having an average particle size in the range of 5 to 50 μm, it is possible to obtain an alkaline zinc battery having excellent heavy load discharge characteristics. By making the shape of the beta-type nickel oxyhydroxide particles spherical, the beta-type nickel oxyhydroxide has a higher density and a larger discharge capacity (battery capacity) can be obtained.

Although the experiment using PTFE as the water repellent has been described in the present embodiment, similar results can be obtained when FEP, fluorinated oil, asphalt, or paraffin is used.

Next, an alkaline battery 200 according to the second embodiment of the present invention will be described. FIG. 5 shows the configuration of the alkaline battery 200 of the second embodiment. The alkaline battery 200 is an AA type battery. Further, in FIG. 5, parts corresponding to those in FIG. 1 are shown with the same reference numerals.

As shown in FIG. 5, this alkaline battery 10
0 is the positive electrode can 11, the positive electrode mixture 12A, and the separator 1
3, the negative electrode 14, and the sealing unit 20. The sealing unit 20 is composed of a negative electrode collector pin 15, a negative electrode terminal plate 16, a sealing member 17, a reinforcing member 18, and a plastic film 22 as a leak preventing means.

The positive electrode mixture 12A is a mixture of beta-type nickel oxyhydroxide and manganese dioxide as a positive electrode active material, carbon powder as a conductive agent, a fluororesin as a binder and an alkaline aqueous solution as an electrolyte. Then, it is formed into a hollow cylindrical shape. The beta-type nickel oxyhydroxide as the positive electrode active material is spherical (including substantially spherical) particles, and preferably has an average particle diameter of 5 to 50 μm. The average particle size of manganese dioxide is 10 to 7
It is preferably 0 μm.

As shown in FIG. 6, the plastic film 22 is formed in a disk shape, and has a through hole for inserting the negative electrode current collecting pin 15 in the center thereof. Plastic film 22
As the material of, nylon, polypropylene, polyethylene or the like can be considered.

As shown in FIG. 7, the plastic film 22 is made of an adhesive agent for the diaphragm 17 of the sealing member 17.
It is bonded to a and is positioned between the opening end of the separator 13 and the sealing member 17 so as to cover the surface of the sealing member 17 facing the inside of the battery.

The other structure is similar to that of the alkaline battery 100 shown in FIG.

The alkaline battery 200 shown in FIG. 5 is manufactured as follows. First, the positive electrode mixture 12A, which is pressure-molded into a hollow cylinder, is inserted into the positive electrode can 11. next,
The bottomed cylindrical separator 13 is inserted into the center of the positive electrode mixture 12A, and the gelled negative electrode mixture 1 is inserted in the separator 13.
Fill 4. Finally, insert the sealing unit 20 with the plastic film 22 adhered to the positive electrode can 11,
The edge of the opening of the positive electrode can 11 is bent inward to fix the sealing unit 20. Sealing unit 2 for positive electrode can 11
When inserting 0, the negative electrode current collector pin 15 welded to the negative electrode terminal plate 16 has a through hole 22a in the plastic film 22.
And is inserted into the gelled negative electrode mixture 14.

Also in the alkaline battery 200 shown in FIG. 5, the current collection of the negative electrode is ensured by inserting the current collection pin 15 welded to the negative electrode terminal 16 into the negative electrode mixture 14. In addition, current collection of the positive electrode is performed by the positive electrode mixture 12A and the positive electrode can 11
It is secured by connecting and.

Here, the following alkaline batteries 200 of Examples 7 to 10 and alkaline batteries of Comparative Example 2 were examined.

In Example 7, an LR6 type (AA type) size positive electrode can 11 was used, which was constituted by an iron plate having a surface plated with nickel. The beta-type nickel oxyhydroxide used for the positive electrode mixture 12A was manufactured by a chemical oxidation method and had spherical particles. Then, the blending ratio of beta-type nickel oxyhydroxide and manganese dioxide was such that the proportion of beta-type nickel oxyhydroxide in the whole positive electrode active material was 30% by mass. Positive electrode mixture,
13. The graphite powder and an aqueous potassium hydroxide solution having a concentration of 30 mass% were weighed at a weight ratio of 80:10:10 and mixed by a stirring method such as an impeller or a ball mill to obtain an outer diameter of 13.
A hollow cylindrical pellet having a diameter of 2 mm, an inner diameter of 9 mm, a height of 13.4 mm, and a mass of 3 g was press-molded and three hollow cylindrical pellets were pressure-molded and used.

The separator 13 has a bottomed cylindrical shape by winding a polyolefin nonwoven fabric into a cylindrical shape and bending the bottom portion inward.

The negative electrode mixture 14 was constituted by a gelled potassium hydroxide aqueous solution containing 65% by weight of granular zinc and 2% by weight of zinc oxide, and 5 g of this was filled.

The plastic film 22 has a thickness of 0.0.
It is formed in a disk shape using a nylon film of 5 mm, and has a through hole for inserting the negative electrode current collector pin 15 in the center (see FIG. 6). This plastic film 22 is adhered and fixed to the diaphragm 17a of the sealing member 17 with an adhesive so as to cover the surface of the sealing member 17 facing the inside of the battery (see FIG. 7).

Further, a hole having a diameter of 0.1 mm is specially formed in the sealing member 17 for an experiment for evaluating the leakage resistance property. It is assumed that the hole is formed in the sealing member 17 when the safety valve 17a is opened or when the sealing member 17 is cracked.

The positive electrode can 11, the positive electrode mixture 12A,
A battery was manufactured using the separator 13, the negative electrode mixture 14, and the sealing member 17 in accordance with the above-described procedure for manufacturing the alkaline battery 200.

In Examples 8 to 10, the thickness of the nylon film as the plastic film 22 was 0.1.
mm, 0.15 mm, and 0.2 mm. Except for that, batteries were produced in the same manner as in Example 1 and in accordance with the above-described procedure for producing the alkaline battery 200.

In Comparative Example 2, the same AA alkaline battery as that used in Example, but without the plastic film 22, was used. A battery was manufactured in the same manner as in Example 7 except for the above and following the procedure for manufacturing the alkaline battery 200 described above.

The alkaline battery 200 of the example and the alkaline battery of the comparative example thus produced were evaluated for leakage resistance and safety under the following test conditions.

The evaluation of the liquid leakage resistance was carried out by making 100 prototypes of each of the batteries shown in Examples and Comparative Examples and setting the batteries at room temperature for 20 minutes.
It was stored at a temperature of 70 ° C. and a humidity of 70%, and the time when the electrolytic solution came out was examined. The safety was evaluated by making 100 prototypes of each of the batteries shown in Examples and Comparative Examples, charging these batteries, and whether or not the batteries burst due to charging. FIG. 8 shows the evaluation result of the leakage resistance property.

From the results shown in FIG. 8, the alkaline batteries 200 of Examples 7 to 10 provided with the plastic film 22.
Does not leak even after 200 days, whereas the alkaline battery of Comparative Example 2 having no plastic film 22 reaches a leak rate of 100% in 4 days. From this, it is clear that the battery provided with the plastic film 22 has excellent leakage resistance.

Table 3 shows the results of safety evaluation.

[0080]

[Table 3]

From the results shown in Table 3, the batteries of Comparative Example 2, Example 7 and Example 8 did not burst by charging. On the other hand, the number of bursts in Example 3 was 3/100, and the number of bursts in Example 4 was 10/100. It is considered that, because the plastic film 22 was thick, the plastic film 22 did not break even if the internal pressure of the battery increased and the battery could not withstand the internal pressure and burst. Therefore, if the thickness of the plastic film 22 is thicker than 0.1 mm, the plastic film 22 may explode when the battery is charged. As a result, the thickness of the plastic film 22 is 0.1 mm.
The following are appropriate:

In this embodiment, an experiment using a nylon film as the plastic film 22 has been described, but similar results can be obtained when using a polypropylene or polyethylene film.

Next, the alkaline batteries 200 of Examples 201 to 240 were examined for the relationship between the particle size distribution of manganese dioxide and the discharge capacity.

Examples 201 to 240 are positive electrode mixture 12A.
The beta-type nickel oxyhydroxide used in 1. was manufactured by a chemical oxidation method, the shape of the particles was spherical, and the average particle diameter of the particles was changed in the range of 5 to 50 μm. On the other hand, the manganese dioxide to be mixed was one in which the average particle size of the particles was changed in the range of 8 to 80 μm. The mixing ratio of beta-type nickel oxyhydroxide and manganese dioxide was 30% by mass of beta-type nickel oxyhydroxide with respect to the whole positive electrode active material. Further, the plastic film 22 has a thickness of 0.1.
mm nylon film was used. Otherwise, Example 7
Batteries were manufactured according to the above-described manufacturing procedure with the same specifications as described above.

Examples 201 to 240 produced in this way
The discharge capacity of the alkaline battery 200 was evaluated under the following test conditions.

The discharge capacity was measured by using an alkaline battery 200
As the discharge conditions, after the battery was manufactured, the discharge time until the discharge end voltage reached 1.0 V was measured by constant power discharge of 1.5 W in an atmosphere of 20 ° C. The results are shown in Table 4.

[0087]

[Table 4]

From the results shown in Table 4, the average particle size of manganese dioxide which prolongs the discharge time of the battery is 10 to 70 μm.
The range is m. Therefore, when the average particle size of manganese dioxide exceeds 70 μm, the repulsive force between particles becomes strong when the positive electrode is pressure-molded, and it is difficult to fill a large amount of the active material per battery. , The discharge time is short,
Heavy load discharge characteristics are degraded. Also, when it is less than 10 μm, the discharge capacity becomes small, and the heavy load discharge characteristics are significantly deteriorated.

As described above, in the present embodiment, the hollow cylindrical positive electrode mixture 1 is provided in the bottomed cylindrical metal positive electrode can 11.
2A is arranged, the negative electrode mixture 14 is arranged in the central portion of the positive electrode mixture 12A via the bottomed cylindrical separator 13, and the metal positive electrode can 11 is sealed by the sealing member 17. A plastic film 22 is provided between the opening end of the separator 13 and the sealing member 17, and the plastic film 22 is fixed to the sealing member 17 with an adhesive so that the electrolytic solution in the separator 13 leaks to the outside due to the creeping up. Is suppressed, and the liquid leakage resistance property when the safety valve 17a is opened or when the sealing member 17 is cracked is improved.

By setting the average particle size of the beta-type nickel oxyhydroxide particles in the range of 5 to 50 μm and the average particle size of the manganese dioxide particles in the range of 10 to 70 μm, the heavy load discharge characteristics are excellent. An alkaline battery can be obtained.

In the above embodiment, nickel-
Although a zinc-based alkaline battery is given as an example, the present invention is not limited to this. It is also effective in a cylindrical alkaline battery using another inside-out type structure.

Further, in the above-mentioned embodiment, the method of applying the water repellent agent to the predetermined range of the opening end of the separator 13 is used in order to make the opening end of the separator 13 water repellent.
It is not limited to this. For example, a method of providing a water repellent material may be used.

Further, in the above embodiment, the alkaline battery 100 using beta-type nickel oxyhydroxide as the positive electrode active material and the alkaline battery 200 using beta-type nickel oxyhydroxide and manganese dioxide have been described. However, manganese dioxide alone may be used as the positive electrode active material.

Further, in the above embodiment, the beta-type nickel oxyhydroxide obtained by the chemical oxidation method was used, but the invention is not limited to this. For example, you may use what was obtained by the electrochemical method.

[0095]

According to the alkaline battery of the present invention,
A hollow cylindrical positive electrode mixture is placed in a bottom cylindrical metal positive electrode can, and a gel containing an alkaline aqueous solution as an electrolytic solution is placed in the center of the positive electrode mixture through a bottomed cylindrical separator. In an alkaline battery in which a negative electrode mixture is arranged and a metallic positive electrode can is sealed with a sealing member, a leak preventing means is provided on the opening end side of the separator to prevent the electrolytic solution from leaking from the sealing member through the separator. Therefore, the leakage of the electrolyte solution to the outside due to the creeping up of the electrolyte solution in the separator is suppressed, and the leakage resistance property is improved.

Further, as the positive electrode active material, beta-type nickel oxyhydroxide having an average particle diameter within a predetermined range, or this beta-type nickel oxyhydroxide and manganese dioxide having an average particle diameter within a predetermined range are used. Therefore, an alkaline battery having excellent heavy load discharge characteristics can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an alkaline battery according to a first embodiment.

FIG. 2 is a diagram showing a configuration of a separator.

FIG. 3 is a diagram showing a relationship between a storage period and a leak rate of a battery.

FIG. 4 is a diagram showing a relationship between a coating range of a water repellent and a discharge capacity.

FIG. 5 is a diagram showing a configuration of an alkaline battery according to a second embodiment.

FIG. 6 is a diagram showing a configuration of a plastic film.

FIG. 7 is a view showing an adhesively fixed state of a plastic film.

FIG. 8 is a diagram showing a relationship between a storage period and a liquid leakage rate of a battery.

FIG. 9 is a diagram showing a configuration of a conventional alkaline battery.

[Explanation of symbols]

1, 100, 200 ... Alkaline battery, 11 ... Positive electrode can, 11a ... Positive electrode terminal, 12, 12A ... Positive electrode mixture, 13 ... Separator, 13a ... Open end, 1
4 ... Negative electrode mixture, 15 ... Negative electrode current collecting pin, 16 ...
・ Negative electrode terminal, 17 sealing member, 17a ... Safety valve, 17
b ... diaphragm, 18 ... reinforcing member, 19 ...
・ Exterior label, 20 ... Sealing unit, 21 ... Coating section, 22 ... Plastic film, 22a ...
Through hole, 23 ... Adhesive part

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5H021 BB12 EE01 EE04 EE07 EE10                       EE35                 5H024 AA03 CC02 CC14 CC19 DD03                       DD09 HH13                 5H050 AA02 AA20 BA04 CA03 CA05                       CB13 DA19 EA21 EA24 FA07                       GA07 GA22 HA04 HA05

Claims (11)

[Claims] 1. A hollow cylindrical positive electrode mixture is placed in a bottomed cylindrical metal positive electrode can, and an alkaline aqueous solution as an electrolytic solution is placed in the center of the positive electrode mixture via a bottomed cylindrical separator. In the alkaline battery in which the gelled negative electrode mixture containing is disposed and the positive electrode can is sealed with a sealing member, on the opening end side of the separator, the electrolytic solution is prevented from leaking from the sealing member through the separator. An alkaline battery, which is provided with a leak prevention means for preventing it. 2. The alkaline battery according to claim 1, wherein the leakage prevention means is configured to be water repellent in a predetermined range of an opening end of the separator. 3. The alkaline battery according to claim 2, wherein the leak prevention means is configured by applying a water repellent agent to a predetermined range of the opening end of the separator. 4. The alkaline battery according to claim 3, wherein the application range of the water repellent agent is 2 to 10 mm from the opening end of the separator. 5. The alkaline battery according to claim 3, wherein the water repellent agent is any one of FEP, PTFE type fluorine resin, fluorinated oil, asphalt, and paraffin in a dispersion state. 6. The alkaline battery according to claim 1, wherein the leakage prevention means is a plastic film provided between the opening end of the separator and the sealing member. 7. The alkaline battery according to claim 6, wherein the plastic film is bonded to the sealing member with an adhesive. 8. The thickness of the plastic film,
It is 0.1 mm or less, The alkaline battery of Claim 6 characterized by the above-mentioned. 9. The alkaline battery according to claim 6, wherein the material of the plastic film is nylon, polypropylene or polyethylene. 10. The positive electrode mixture contains beta-type nickel oxyhydroxide, or beta-type nickel oxyhydroxide and manganese dioxide as a positive electrode active material, and the beta-type nickel oxyhydroxide is a spherical particle and has an average particle size. The alkaline battery according to claim 1, wherein the particle diameter is 5 to 50 µm, and the average particle diameter of the manganese dioxide is 10 to 70 µm. 11. The alkaline battery according to claim 1, wherein the negative electrode mixture contains zinc as a negative electrode active material.