JP2004119194A - Alkaline battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a gas caused by iron melting, where the iron is exposed on the surface of a positive electrode can, from generating a gas inside an alkaline battery, and to enhance liquid-leakage-resistance performance of the alkaline battery, where the positive electrode can is made of steel and plated with nickel or the like, and the alkaline battery is sealed and uses a positive electrode complex agent including manganese dioxide and/or nickel oxyhydroxide as a main ingredient and a negative electrode complex agent including zinc as a main ingredient. <P>SOLUTION: In the sealed alkaline battery, a positive electrode complex agent 12 including manganese dioxide and/or nickel oxyhydroxide as a main ingredient, a separator 13 impregnated with an alkaline electrolyte, and a negative electrode complex agent 14 including zinc as a main ingredient are loaded inside a positive electrode can 11 into which a nickel-plated steel sheet is formed by press working or the like and which is in a bottomed cylindrical shape and also serves as a positive electrode terminal, and an opening of the positive electrode can 11 is sealed with an insulating gasket 23 and a negative electrode terminal 21, where a non-metallic film layer 12 is formed on the inside surface of the positive electrode can 11 from the opening to the intersection of the positive electrode can 11 and the positive electrode complex agent 12. <P>COPYRIGHT: (C)2004,JPO

Description

【００２１】
表１からあきらかなように、正極缶に非金属性被覆の塗布を行った電池の漏液発生率は、塗布を行っていない従来品に比べて、漏液発生率が顕著に低下している。
【００２２】
以上のように、実施例では、非金属性被覆としてピッチ、シリコンオイル、ＰＥ、ＰＰをそれぞれ用いたが、いずれの場合も、表面露出した鉄の溶解により生じる電池内部でのガス発生を確実に防止し、これにより耐漏液性能を高めることができた。
【００２３】
以上、本発明をその代表的な実施例に基づいて説明したが、本発明は上述した以外にも種々の態様が可能である。たとえば、非金属性被覆は上記以外の塗材または被覆材でもよい。また、本発明は、ニッケル以外の鉄よりも貴な金属でメッキされた金属製正極缶にも適用可能である。
【００２４】
【発明の効果】
ニッケル等でメッキされた鋼製の正極缶と、二酸化マンガンおよび／またはオキシ水酸化ニッケルを主成分とする正極合剤と、亜鉛を主剤とする負極合剤を使用する密閉型のアルカリ電池において、表面露出した鉄の溶解により生じる電池内部でのガス発生を確実に防止することができ、これによりアルカリ電池の耐漏液性能を高めることができる。
【図面の簡単な説明】
【図１】本発明によるアルカリ電池の一実施例を示す断面図である。
【図２】正極缶からの鉄溶出状態を部位別に示すグラフである。
【図３】本発明電池と従来電池についてそれぞれ正極缶からの鉄溶出状態を示すグラフである。
【符号の説明】
１１　　正極缶
１１１　鉄を主成分とする下地金属（鋼）層
１１２　ニッケルメッキ層
１２　　正極合剤
１３　　パレータ
１４　　負極合剤
１５　　負極集電子
２０　　封口体
２１　　負極端子
２２　　絶縁リング
２３　　電気絶縁ガスケット
３１　　外装材
５３　　非金属被膜層[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sealed alkaline battery using a positive electrode can formed by processing a steel plate plated with nickel or the like into a bottomed cylindrical shape, and is applied to, for example, an LR03 type (AA) alkaline dry battery.
[0002]
[Prior art]
Alkaline dry batteries such as LR03 are equipped with a positive electrode mixture, a separator impregnated with an alkaline electrolyte, and a negative electrode mixture mainly composed of zinc, in a bottomed cylindrical metal positive electrode can, and open the opening of the positive electrode can. It is configured by sealing with an insulating gasket and a negative electrode terminal. In this case, the positive electrode can is formed by pressing a nickel-plated thin steel plate. The positive electrode mixture is a cylindrical molded mixture containing manganese dioxide, nickel oxyhydroxide, or manganese dioxide and nickel oxyhydroxide as main components, and is loaded into the positive electrode can in a press-fitted state. A separator is arranged inside the positive electrode mixture, the inside of the separator is filled with a gelled negative electrode mixture, and the separator is impregnated with an alkaline electrolyte to form a power generating element. The electromotive force of the power generating element is collected by the positive electrode can in contact with the positive electrode mixture and the negative electrode current collector inserted into the negative electrode mixture. The positive electrode can also serves as a positive electrode terminal. The negative electrode current collector is connected to a negative electrode terminal forming a part of the sealing body.
[0003]
[Problems to be solved by the invention]
The above-mentioned positive electrode can of an alkaline battery is manufactured by pressing a nickel-plated thin steel plate, but the surface of the nickel-plated steel plate is not necessarily limited to the nickel surface, and iron (Fe) of the base may be pinholes or diffused. It is inevitable to partially expose the surface. This surface exposure of iron affects corrosion resistance. Therefore, a nickel-plated steel sheet whose exposure ratio of iron has been suppressed to a specified value or less has been provided (for example, JP-A-6-2104).
[0004]
However, the exposure ratio of iron changes, for example, in a can-making process such as press working. Often. Even if the exposure ratio of iron could be suppressed to the specified value or less, it was found that the following problem would occur when used as a positive electrode can of an alkaline battery.
[0005]
That is, the iron exposed on the inner surface of the positive electrode can is exposed to the alkaline electrolyte. In this case, if only iron is considered, iron is passivated in a strong alkaline solution and is hardly corroded. However, in the presence of metals noble than iron, such as nickel, oxidizing agents manganese dioxide and / or nickel oxyhydroxide, and air (oxygen), iron is ionized and dissolved, and this iron ion is dissolved in the negative electrode mixture. Reacts with zinc to generate hydrogen gas. This gas generation inside the battery causes liquid leakage.
[0006]
The present invention has been made in view of the above problems, and has as its object to provide a steel positive electrode can plated with nickel or the like, and a positive electrode mainly composed of manganese dioxide and / or nickel oxyhydroxide. In a sealed alkaline battery using a mixture and a negative electrode mixture containing zinc as a main component, reliably prevent gas generation inside the battery caused by dissolution of iron exposed on the surface, and thereby improve leakage resistance. It is in.
[0007]
[Means for Solving the Problems]
Means of the present invention is to provide manganese dioxide and / or nickel oxyhydroxide in a metal-made positive electrode can which also serves as a positive electrode terminal in a bottomed cylindrical shape whose main component is iron and at least the inner surface is plated with a metal nobleer than iron. And a separator impregnated with an alkaline electrolyte, and a zinc-based negative electrode mixture, and sealing the opening of the positive electrode can with an insulating gasket and a negative electrode terminal. Wherein a non-metallic coating layer is provided on an inner surface from an opening of the positive electrode can to a portion in contact with the positive electrode mixture.
[0008]
By the above means, ionization of iron due to the presence of metals nobler than iron, such as nickel, oxidizing agents manganese dioxide and / or nickel oxyhydroxide, and air (oxygen) is effectively prevented. As a result, it is possible to reliably prevent gas generation inside the battery caused by dissolution of the iron exposed on the surface, thereby improving the leakage resistance of the alkaline battery.
[0009]
In the above means, an oil-based paint such as pitch or silicone oil or an olefin-based resin such as PE (polyethylene) or PP (polypropylene) can be used for the non-metallic coating layer. The oil-based paint has an advantage that application is easy, and the olefin-based resin has an advantage that a coating layer is strong.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows an embodiment of an alkaline battery to which the technology of the present invention is applied. The battery shown in FIG. 1 is an alkaline dry battery called an LR03 type, and has a bottomed cylindrical metal positive electrode can 11 also serving as a positive electrode terminal, a positive electrode mixture 12 containing manganese dioxide and / or nickel oxyhydroxide as a main component. And a separator 13 impregnated with an alkaline electrolyte, a negative electrode mixture 14 mainly composed of zinc, a negative electrode current collector 15, a sealing body 20, an exterior material 31, and the like.
[0011]
The positive electrode can 11 is formed by processing a nickel-plated thin steel plate into a cylindrical shape with a bottom by pressing or the like. As shown in FIG. It has a steel (steel) layer 111 and a nickel plating layer 112, and the nickel plating layer 112 covers the inner surface of the positive electrode can 11. The outer periphery of the positive electrode can 11 is covered with an insulative exterior material 15 such as label printing.
[0012]
The positive electrode mixture 12 is a cylindrical molded mixture containing manganese dioxide, nickel oxyhydroxide, or manganese dioxide and nickel oxyhydroxide as main components, and is loaded into the positive electrode can 11 by press-fitting. A separator 13 is arranged inside the positive electrode mixture 12, and the inside of the separator 13 is filled with a gelled negative electrode mixture 14, and the separator 13 is impregnated with an alkaline electrolyte to form a power generating element. Is done.
[0013]
The electromotive force of the power generating element is collected by the positive electrode can 11 in contact with the positive electrode mixture 12 and the negative electrode current collector 15 inserted in the negative electrode mixture 14. The positive electrode can 11 also serves as a positive electrode terminal. The negative electrode current collector 15 is connected to a negative electrode terminal 21 forming a part of the sealing body 20. The sealing body 20 includes a negative electrode terminal 21, an insulating ring 22, an electrically insulating gasket 23, and the like, and hermetically seals an upper opening of the positive electrode can 11.
[0014]
Further, in the above alkaline battery, as shown in a partially enlarged view in the same drawing, a non-metallic coating layer is formed on the inner surface from the opening of the positive electrode can 11 to a portion (range indicated by the symbol h) in contact with the positive electrode mixture 12. 53 are provided. As a material for forming the non-metallic coating layer 53, an oil paint or an olefin resin is suitable.
[0015]
According to the above-described configuration, it is possible to reliably prevent the generation of hydrogen gas due to dissolution of iron exposed on the inner surface of the positive electrode can 11 for a long period of time while securing the electrical contact state between the positive electrode can 11 and the positive electrode mixture 12. There was found. This is thought to be due to the fact that the ionization of iron due to the presence of nickel, which is a noble metal than iron, oxidizing agents manganese dioxide and / or nickel oxyhydroxide, and air (oxygen) is effectively prevented. Can be Thereby, the liquid leakage resistance can be improved without impairing the battery performance.
Hereinafter, specific examples of the present invention will be described.
[0016]
(Comparative example)
Using a positive electrode can processed from a nickel-plated steel sheet, an LR03 type alkaline dry battery was produced. The nickel-plated steel sheet used had an iron ratio of 20 to 25% by weight at the exposed surface. The nonmetallic coating was not provided on the inner surface of the positive electrode can. When the amount of Fe eluted from the positive electrode can when the battery was stored at 90 ° C. was examined for each site and for the number of storage days, the results shown in FIG. 2 were obtained.
[0017]
In the figure, the amount of Fe eluted was determined by dividing the battery into three parts A, B, and C (see FIG. 1), and measuring the amount of elution for each of the parts (A, B, and C) according to the number of storage days. A point A in the graph of the same figure indicates the amount of Fe eluted at the upper third site A of the positive electrode can. This portion A includes the upper end portion (in the direction of the sealing portion) of the positive electrode mixture. Point B indicates the amount of Fe eluted at the lower intermediate site B. Point C indicates the amount of Fe eluted at lower 1/3 site C reaching the bottom of the positive electrode can. As is apparent from the figure, it was found that the amount of Fe eluted from the positive electrode can was specifically large in the portion A including the upper end portion of the positive electrode mixture.
[0018]
(Example)
Using a positive electrode can processed from a nickel-plated steel sheet, an LR03 type alkaline dry battery of the same type as the comparative example was produced. The nickel-plated steel sheet used had an iron ratio of 20 to 25% by weight at the exposed surface. A nonmetallic coating was applied to the inner surface of the positive electrode can prepared by pressing the plated steel sheet. The coating was performed on the inner surface from the opening of the positive electrode can to a portion (range indicated by reference numeral h) in contact with the positive electrode mixture 12. As the nonmetallic coating, pitch, silicone oil, PE (polyethylene), and PP (polypropylene) were used, and test batteries were manufactured for each. PE and PP were applied by dissolving PE or PP in benzene or toluene at 70 ° C. or higher. Separately, for comparison, a test battery of a conventional configuration without a non-metallic coating was also fabricated. When the amount of Fe eluted from the positive electrode can when each test battery was stored at 90 ° C. (the amount of elution in the entire positive electrode can) was examined for each storage day, the results shown in FIG. 3 were obtained. As is clear from the figure, the Fe elution amount in the battery coated with the non-metallic coating is significantly smaller than that in the battery without the coating (conventional product).
[0019]
Table 1 shows that at 90 ° C., 30% R.D. The result of a liquid leakage resistance test under the condition of H is shown. The test was performed using 100 samples (N = 100) for each type.
[0020]
[Table 1]

[0021]
As is clear from Table 1, the leakage rate of the battery in which the nonmetallic coating was applied to the positive electrode can was significantly lower than that of the conventional product in which the coating was not performed. .
[0022]
As described above, in the examples, pitch, silicon oil, PE, and PP were used as the non-metallic coating, but in any case, gas generation inside the battery caused by dissolution of iron exposed on the surface was ensured. Thus, the liquid leakage resistance could be improved.
[0023]
As described above, the present invention has been described based on the typical embodiments. However, the present invention can have various aspects other than those described above. For example, the non-metallic coating may be a coating or coating other than those described above. In addition, the present invention is also applicable to a metal positive electrode can plated with a metal other than nickel, which is more noble than iron.
[0024]
【The invention's effect】
In a sealed alkaline battery using a steel positive electrode can plated with nickel or the like, a positive electrode mixture mainly containing manganese dioxide and / or nickel oxyhydroxide, and a negative electrode mixture mainly containing zinc, Gas generation inside the battery caused by dissolution of the iron exposed on the surface can be reliably prevented, thereby improving the liquid leakage resistance of the alkaline battery.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an embodiment of an alkaline battery according to the present invention.
FIG. 2 is a graph showing the state of iron elution from a positive electrode can by site.
FIG. 3 is a graph showing the state of iron elution from the positive electrode can for the battery of the present invention and the conventional battery.
[Explanation of symbols]
REFERENCE SIGNS LIST 11 positive electrode can 111 base metal (steel) layer mainly composed of iron 112 nickel plating layer 12 positive electrode mixture 13 parator 14 negative electrode mixture 15 negative electrode current collector 20 sealing body 21 negative electrode terminal 22 insulating ring 23 electrically insulating gasket 31 exterior material 53 Non-metallic coating layer

Claims (4)

A positive electrode mainly composed of manganese dioxide and / or nickel oxyhydroxide in a metal-made positive electrode can that also serves as a positive electrode terminal with a bottomed cylindrical shape whose main component is iron and at least the inner surface is plated with a metal nobler than iron A mixture, a separator impregnated with an alkaline electrolyte, and a negative electrode mixture containing zinc as a main component are loaded, and in a sealed alkaline battery in which the opening of the positive electrode can is sealed with an insulating gasket and a negative electrode terminal, the positive electrode can is sealed. An alkaline battery, wherein a nonmetallic coating layer is provided on an inner surface from an opening to a portion in contact with the positive electrode mixture. 2. The alkaline battery according to claim 1, wherein the non-metallic coating layer comprises an oil-based paint. 2. The alkaline battery according to claim 1, wherein the non-metallic coating layer is made of an olefin-based resin. The alkaline battery according to any one of claims 1 to 3, wherein the positive electrode can is formed by processing a nickel-plated steel plate into a bottomed cylindrical shape.

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