JP2003257440A - Alkaline primary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reliable alkaline primary battery by preventing liquid leakage which easily occurs in the case of using nickel oxyhydroxide as a positive electrode material of the alkaline primary battery in order to improve the high load property and increase the capacity. <P>SOLUTION: A positive electrode molded body 2 of the alkaline primary battery contains nickel oxyhydroxide as a positive electrode active material in a positive electrode mixture and the nickel oxyhydroxide contains cobalt and zinc. In a battery can 4, the positive electrode molded body 2 and zinc as a negative electrode active material 8 are arranged while being separated by a separator 6. The separator 6 is made of a polymer film having hydrophilicity and pores. The positive electrode molded body 2 has a hollow cylindrical shape, the center part of which the negative electrode active material 8 is arranged while being separated by the separator 6 to constitute an inside-out type battery. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alkaline primary battery containing nickel oxyhydroxide in a positive electrode mixture, and particularly to a technique for improving heavy load discharge characteristics and self-discharge characteristics under high temperature storage. is there.

[0002]

2. Description of the Related Art At present, as an alkaline primary battery having a high output characteristic, an alkaline manganese battery using manganese dioxide as a positive electrode active material, zinc as a negative electrode active material and an alkaline aqueous solution as an electrolyte is mainly used. However, in recent years, with the increasing performance of mobile devices such as digital cameras and information communication terminals, the alkaline primary battery used as the power source has a heavy load characteristic. The demands for further improvement and higher capacity are increasing. In addition, in alkaline secondary batteries, β-type or γ-type nickel oxyhydroxide is applied to the positive electrode active material as a means capable of supplying a battery having excellent output characteristics in response to the above demands. Has been noticed and studied for a long time (Japanese Patent Laid-Open No. 53-32347 and Japanese Patent Laid-Open No. 55-30133).
No.

[0003]

By the way, in the alkaline secondary battery constituted by using the above-mentioned β-type or γ-type nickel oxyhydroxide as the positive electrode active material, which has been studied conventionally, self-discharge occurs when left at high temperature for a long time. Therefore, there is a problem that the battery capacity is reduced. Therefore, the β-type or γ-type conventional nickel oxyhydroxide cannot be used as it is as a positive electrode material of an alkaline primary battery, and has not been put into practical use. That is, for the primary battery, the capacity decrease due to self-discharge means the disappearance of the battery function, and therefore it is essential to improve the capacity decrease due to self-discharge for practical use.

Therefore, the inventors of the present invention conducted various kinds of detailed experiments and the like on nickel oxyhydroxide for the purpose of improving self-discharge which occurs when left at high temperature for a long time, and proceeded with research and development. As a result of repeated studies, it was found that simultaneous solid solution substitution of nickel oxyhydroxide with cobalt and zinc can suppress self-discharge and can be applied to primary batteries. We have already proposed an alkaline primary battery using nickel oxyhydroxide containing zinc as a positive electrode active material.

However, in the subsequent research and development, if nickel oxyhydroxide is solid-solution-substituted with cobalt and zinc, it becomes difficult to grow the powder particles of nickel oxyhydroxide, that is, the aggregate particle size of crystals. ,
It has been found that the proportion of fine particles increases. That is, when the abundance ratio of the nickel oxyhydroxide fine particles in the nickel oxyhydroxide powder used as the positive electrode material increases, the fine particles easily pass through the separator and are easily mixed in the negative electrode. When nickel oxyhydroxide is mixed in the negative electrode side, gas is generated in the negative electrode, which leads to leakage of the battery, leading to a decrease in reliability.

Table 1 shows the results of the nickel oxyhydroxide separator permeability test. A vinylon / rayon nonwoven fabric (thickness: 100 μm, basis weight: 30 g / m ² ) was used as the separator in this permeability test. The separator is double wound into a cylindrical shape with an inner diameter of 8 mm, 2 g of nickel oxyhydroxide powder is placed inside, and both ends of the cylindrical separator are sealed by heat fusion to make the inside. Enclose the above powder in a
After dipping in a weight% potassium hydroxide electrolytic solution and storing at 45 ° C. for 10 days, the amount of nickel contained in the electrolytic solution was measured by atomic absorption spectrometry to determine the amount of nickel oxyhydroxide that had permeated through the separator. It is quantified.

As shown in Table 1, the detected amount of nickel oxyhydroxide in which cobalt and zinc are not solid-solution-substituted is 10
When expressed as a relative value as 0, nickel oxyhydroxide having solid solution substitution of cobalt and zinc has reached 180,
The permeability was as high as 80%.

[0008]

[Table 1]

The present invention has been made in view of the above circumstances, and an object thereof is to use nickel oxyhydroxide as a positive electrode material of an alkaline primary battery in order to improve high load characteristics and increase capacity. Another object of the present invention is to provide an alkaline primary battery capable of preventing the occurrence of liquid leakage, which tends to occur easily, and improving reliability.

[0010]

In order to achieve the above object, in an alkaline primary battery of the invention according to claim 1, a positive electrode mixture contains nickel oxyhydroxide as a positive electrode active material, and a separator An alkaline primary battery in which zinc, which is a negative electrode active material, is arranged through the nickel oxyhydroxide, which contains cobalt and zinc simultaneously as solid solution substitution elements, and the separator is a polymer having fine pores. It is characterized by being composed of a film.

In the alkaline primary battery of the invention according to claim 2, an alkaline primary battery in which a mixture of nickel oxyhydroxide and manganese dioxide is used as a positive electrode active material and zinc as a negative electrode active material is arranged through a separator. The battery is characterized in that the nickel oxyhydroxide simultaneously contains cobalt and zinc as solid solution substitution elements, and the separator is composed of a polymer film having fine pores.

The alkaline primary battery of the invention according to claim 3 is the alkaline primary battery according to claim 1 or 2, characterized in that the polymer film of the separator has hydrophilicity. To do.

In the alkaline primary battery of the invention according to claim 4, in the alkaline primary battery according to claims 1 to 3, the separator has a laminated structure of the polymer film and a nonwoven fabric. It is characterized by

In the alkaline primary battery of the invention according to claim 5, in the alkaline primary battery according to claims 1 to 4, the separator has a laminated structure of the polymer film and a nonwoven fabric. It is characterized by

That is, when the nickel oxyhydroxide containing cobalt and zinc is used as the positive electrode active material as in the alkaline primary battery according to the present invention having the above-mentioned structure, it is possible to allow the migration of ions. By using the polymer film having the micropores as the separator, the mixture of the positive electrode active material into the negative electrode side is significantly suppressed as compared with the case where only the nonwoven fabric is used as the separator.

However, since an alkaline aqueous solution is used as the electrolytic solution, it is desirable that the polymer film material serving as the separator has hydrophilicity. Examples of the polymer film having hydrophilicity and micropores include a cellulose-based film having a hydrophilic functional group (hydrophilic group) in the molecule, a polypropylene film or a polyethylene film which has been treated to add hydrophilicity. To be Examples of the hydrophilic treatment include corona discharge treatment and primer treatment, but any treatment may be performed as long as it is a treatment for adding hydrophilicity. Also, polymer film materials other than the above can be used as long as they have a hydrophilic functional group.

The above-mentioned polymer membrane having ion permeability and the microporous film having a small pore size may be used alone, but may be used in combination by laminating them with a non-woven fabric, if necessary. I don't care. Examples of the polymer fiber that can be used as the nonwoven fabric include vinylon fiber, vinylon fiber, polyamide fiber, hydrophilized polypropylene, hydrophilized polyethylene, rayon, linter pulp, and mercerized pulp as single fibers. Also, a composite of the above-mentioned single fibers can be used, and examples thereof include a polyolefin-rayon nonwoven fabric, a vinylon-rayon nonwoven fabric, and a composite fiber of hydrophilic polyethylene-hydrophilic polypropylene. In addition, as a non-woven fabric, a hydrophilic treated product of a core-sheath type composite fiber (polypropylene for the core material and polyethylene for the sheath material) can also be used.

As described above, by using the film having the function of suppressing the permeation of fine particles as the separator, it is possible to suppress the mixing of the positive electrode active material into the negative electrode and form a highly reliable battery. Become.

Further, by forming the positive electrode mixture into a hollow cylindrical molded body and inserting the positive electrode mixture into a battery can, the negative electrode active material is arranged in the center of the positive electrode mixture through a separator to form an inside-out type battery, Further cost reduction can be achieved.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the alkaline primary battery according to the present invention will be described below.

First Embodiment === Preparation of Positive Electrode === Nickel sulfate, cobalt sulfate, and zinc sulfate were mixed so that the atomic weight ratios of nickel, cobalt, and zinc were predetermined ratios. 1000 ml of mixed solution at 30 ° C
In the reaction tank kept in the above condition, an aqueous sodium hydroxide solution is added so that the pH becomes 11, and the mixture is stirred. After stirring for about 1 hour, the generated precipitate is filtered out and washed with water. After washing, vacuum drying is performed at room temperature to obtain a powder sample.

Next, 100 g of the above powder sample was added to a 10 mol / l sodium hydroxide aqueous solution and stirred,
Keep the solution temperature between 30 ° C and 60 ° C. While stirring the solution, 500 wt% aqueous solution of sodium hypochlorite 500
After adding ml, stirring for about 1 hour, the precipitate was taken out by filtration, washed with water, and then washed.
Vacuum drying is performed at a temperature of 60 ° C. or lower.

Nickel oxyhydroxide 10 obtained by the above method
A hollow cylinder is prepared by mixing 0% by weight, 10% by weight of a conductive agent (graphite powder), and 5% by weight of an electrolytic solution (40% by weight potassium hydroxide aqueous solution) to prepare a mixture, and performing pressure molding. A shaped body was prepared and used as a positive electrode.

=== Preparation of Negative Electrode === As a negative electrode active material, 60% by weight of zinc powder, 40% by weight of aqueous potassium hydroxide solution containing zinc oxide in a saturated state, and 1% by weight of acrylic acid resin were added to form a gel. -Shaped zinc was prepared and used as a negative electrode.

=== Preparation of Separator === A conventional vinyl-rayon nonwoven fabric (thickness: 100 μm, basis weight:
30 g / m ² ) and the bottom side of each is closed and the inner diameter is 8
The separator was manufactured by double-winding into a cylindrical shape so as to have a thickness of mm.

In this embodiment, cellophane and a hydrophilized polyethylene film are used as the polymer film, and the vinylon / rayon nonwoven fabric is laminated on each of the cellophane and the hydrophilized polyethylene film.
Created a kind of separator.

Table 2 shows, as a reference, the results of the nickel oxyhydroxide permeability test conducted on the separator composed of the cellophane, the hydrophilized polyethylene film, and the vinylon / rayon nonwoven fabric. In this permeability test, 2 g of nickel oxyhydroxide powder not subjected to solid solution substitution was placed inside the separator so that the separator had an inner diameter of 8 mm and was double wound into a cylindrical shape. The above powder was sealed inside by sealing both ends by heat fusion, and the powder was immersed in a 40 wt% potassium hydroxide electrolytic solution and stored at 45 ° C. for 10 days. The amount of nickel oxyhydroxide that has passed through the separator is quantified by measuring the amount of nickel contained therein by plasma emission analysis.

[0028]

[Table 2]

As shown in Table 2, when the detected amount of nickel oxyhydroxide permeated through the conventional vinylon / rayon non-woven fabric is set to 100 and shown as a relative value, it is 40 for cellophane and 45 for hydrophilized polyethylene. The sex is halved.

=== Production of Battery === As shown in FIG. 1, the positive electrode molded body 2 is inserted and arranged in a state of being closely attached to a battery can 4 having a bottomed cylindrical shape, and the positive electrode molded body is also placed. The separator 6 is inserted and arranged inside 2, and a 40 wt% K0H aqueous solution is injected as an electrolytic solution, and then the negative electrode 8 is injected and filled in the central portion inside the separator 6. The filling amount was adjusted so that the theoretical capacity of the positive electrode: the theoretical capacity of the negative electrode would be 1: 1.1. Further, the opening of the battery can 4 was sealed by using a negative electrode terminal 16 in which a current collector 10, a gasket 12 and a negative electrode lid 14 were integrated, and an intended AA size alkaline battery was produced as an inside-out type. .

==== Example ==== << First Embodiment >> As Example 1, 20 batteries were manufactured by the above method using a separator in which cellophane and a vinylon / rayon nonwoven fabric were laminated. Also, as Example 2, 20 batteries were manufactured by the same method as above, using a separator obtained by laminating a hydrophilic polyethylene film and a vinylon / rayon nonwoven fabric. Further, as Comparative Example 1, 20 batteries using a conventional vinylon / rayon non-woven fabric as a separator were prepared by the above method.

Then, all the batteries of Examples 1 and 2 and Comparative Example 1 were stored in a constant temperature bath at 90 ° C. for 10 days, and the number of leaked liquids after storage were confirmed to conduct a battery reliability test. went. The results are shown in Table 3.

[0033]

[Table 3]

As shown in Table 3, in Examples 1 and 2 in which a separator in which a polymer film having hydrophilicity and fine pores and a vinylon / rayon nonwoven fabric were laminated was used, liquid leakage was observed in all 20 pieces. No occurrence was observed, and all products passed and the pass rate was 100%, while in Comparative Example 1 using the separator made of the vinylon / rayon nonwoven fabric,
Liquid leakage occurred in 13 of the pieces and the number of passed pieces was only 7, and the pass rate was only 35%.

<< Second Embodiment >> The alkaline primary battery of the second embodiment is different from the alkaline primary battery of the first embodiment except that manganese dioxide is further added to the active material used for the positive electrode. An AA alkaline battery was manufactured with the same battery configuration. Here, the mixing ratio of the nickel oxyhydroxide and manganese dioxide is 7
It was set to 5:25.

Then, the same reliability test as in the first embodiment was conducted on each of the above Examples 3 to 4 and Comparative Example 2. The results are shown in Table 4.

[0037]

[Table 4]

As shown in Table 4, even when the positive electrode mixture is a mixture of nickel oxyhydroxide and manganese dioxide, a separator obtained by laminating a polymer film having hydrophilicity and fine pores and a vinylon / rayon nonwoven fabric is laminated. In Examples 3 and 4 in which No. 20 was used, no liquid leakage was observed, and all products passed and the pass rate was 100%. In Comparative Example 2 used, the liquid leakage occurred in 10 out of 20, and the number of passes was 10, and the pass rate was only 50%.

Therefore, even when nickel oxyhydroxide and manganese dioxide are mixed and used as the positive electrode active material, it is possible to improve battery reliability by using a polymer film having hydrophilicity and fine pores as the separator. It has been found to be extremely effective above.

In each of the alkaline primary batteries of the first and second embodiments, the positive electrode mixture is made into a hollow cylindrical molded body 2 and inserted into the battery can 4, and the separator 6 is placed at the center thereof. The battery is configured as an inside-out type battery in which the negative electrode active material is arranged via the anode active material, and by using such an inside-out type battery, the cost of the battery can be reduced.

[0041]

As described above, according to the present invention, when nickel oxyhydroxide containing cobalt and zinc is used as a positive electrode active material to form an alkaline primary battery, it is possible to move ions. By using a polymer film having minute pores that can be made as a separator, it is possible to significantly suppress the mixing of the positive electrode active material into the negative electrode side compared to the case where only a nonwoven fabric is used for the separator. become. For this reason, it becomes possible to prevent the generation of gas due to the mixing of nickel oxyhydroxide on the negative electrode side as much as possible, thereby suppressing the occurrence of liquid leakage and improving the reliability of the battery.

Further, by forming the positive electrode mixture into a hollow cylindrical molded body and inserting it into the battery can, and constituting the inside-out type battery in which the negative electrode active material is arranged in the center portion thereof via the separator, Cost reduction can be achieved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an alkaline primary battery according to the present invention.

[Explanation of symbols]

2 Positive electrode molding 4 battery cans 6 separator 8 Negative electrode 10 Collective Electronics 12 gasket 14 Negative electrode lid 16 Negative electrode terminal

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01M 4/52 H01M 4/52 (72) Inventor Mitsuhiro Nakamura 5 36-11 Shinbashi, Minato-ku, Tokyo F・ D-K Co., Ltd. (72) Inventor Hiroto Sagisaka 5-36-11 Shimbashi, Minato-ku, Tokyo F-D-K Co., Ltd. (72) Inventor Takeshi Miyazaki Shimbashi, Minato-ku, Tokyo 5th 36th-11th F-D-K Co., Ltd. F-term (reference) 5H021 AA02 CC04 EE02 5H024 AA01 CC02 CC06 CC07 DD09 DD14 EE09 FF31 FF34 5H050 AA02 AA09 AA10 AA15 AA20 BA04 CA03 CA30 CB13 DA15 EA23 FA07 FA07

Claims (5)

[Claims] 1. An alkaline primary battery in which a positive electrode mixture contains nickel oxyhydroxide as a positive electrode active material, and zinc as a negative electrode active material is arranged through a separator, wherein the nickel oxyhydroxide is cobalt and zinc. An alkaline primary battery, which contains, as a solid solution substitution element at the same time, and the separator is composed of a polymer film having fine pores. 2. An alkaline primary battery in which a mixture of nickel oxyhydroxide and manganese dioxide is used as a positive electrode active material and zinc, which is a negative electrode active material, is arranged through a separator, wherein the nickel oxyhydroxide is cobalt. An alkaline primary battery comprising zinc and a solid solution substitution element at the same time, and the separator is composed of a polymer film having fine pores. 3. The alkaline primary battery according to claim 1, wherein the polymer film of the separator has hydrophilicity. 4. The alkaline primary battery according to claim 1, wherein the separator has a laminated structure of the polymer film and a nonwoven fabric. 5. The inside-out type structure in which the positive electrode active material is formed into a hollow cylindrical molded body, and the zinc of the negative electrode active material is disposed in the center of the positive electrode active material molded body via a separator. The alkaline primary battery according to any one of claims 1 to 4, wherein