JP4181880B2 - Alkaline battery - Google Patents

Description

【００２１】
以上の実験結果から、突起の幅を小さくすることによって負極端子板表面における漏液数を減少させることができ、好ましくはその突起幅の合計値がその突起を通る全円周長に対して３．０％以下とすることである。
【００２２】
【発明の効果】
本発明によれば、乾電池内の電解液のカリウムイオンは負極端子板の内面に接触する狭幅の突起部分においてナイロン製ガスケットを透過するのみであるから、その透過量を少なくして端子板表面への電解液の漏出を防止することができる。
【図面の簡単な説明】
【図１】本発明のアルカリ乾電池を示す縦断面図である。
【図２】本発明のアルカリ乾電池に適用したナイロン製ガスケットを示す斜視図である。
【図３】本発明の実験に使用したガスケットの突起の幅と円周とを示す説明図である。
【符号の説明】
１ 正極缶
２ 負極ゲル
３ セパレータ
４ 正極合剤
５ ガスケット
５ａ ボス部
５ｂ 立上がり部
５ｃ 薄肉部
５ｄ 内周底部
５ｅ 環状凸部
５ｆ 外周底部
５ｇ 第１の山形突起
５ｈ 第２の山形突起
６ 負極端子板
７ 集電子
８ メタルラベル[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an alkaline battery including a gasket that is interposed between an opening of a positive electrode can and a negative electrode terminal plate and seals between the two.
[0002]
[Prior art]
Conventionally, as a material for a sealing gasket of an alkaline battery, polypropylene or nylon having usually excellent alkali resistance has been used. However, the heat resistance of polypropylene is inferior, so if the dry battery generates heat due to short-circuiting or reverse insertion of the dry battery, the polypropylene gasket will be deformed, and the thin part provided for battery explosion protection will not function correctly. There is. On the other hand, since the nylon resin is relatively excellent in heat resistance, the gasket is not easily deformed even when heat is generated due to the above-mentioned misuse, and it ruptures relatively accurately at a predetermined internal pressure.
[0003]
[Problems to be solved by the invention]
However, in the case of a dry battery using a gasket made of nylon resin, the relatively thin portion of the gasket is in contact with the negative electrode terminal plate at 75 ° C. and 90% R.D. When placed in H (Relative Humidity) for one week, leakage of the electrolyte composed of potassium hydroxide occurs on the surface of the negative electrode terminal plate.
[0004]
On the other hand, even if an alkaline battery having the same configuration as that described above using a polypropylene gasket is stored for a long time in the same high-temperature and high-humidity environment as described above, the electrolyte solution made of potassium hydroxide remains in the negative electrode terminal. There is no leakage on the plate surface.
[0005]
Further, even in the case of a dry battery having the above-described configuration using a nylon gasket, the above-described liquid leakage phenomenon does not occur when stored in an environment that is not hot and humid (for example, 75 ° C. dry or room temperature). For this reason, when the relatively thin portion of the nylon gasket absorbs moisture in a high-temperature and high-humidity environment, the present inventors contact potassium ions (K +) from the inside of the battery with the negative electrode terminal plate. Permeated from the inner surface of the gasket to the outer surface at the part, then moved on the negative electrode terminal plate along the outer surface of the gasket and combined with moisture (OH-) as a liquid leakage phenomenon (generation of aqueous potassium hydroxide) The present invention has been achieved based on such inferences.
[0006]
Accordingly, an object of the present invention is to provide electrolyte leakage to the negative electrode terminal plate surface in an alkaline battery having a nylon gasket that is interposed between the opening of the positive electrode can and the negative electrode terminal plate and seals between the two. It is in providing a structure for preventing the above.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, in the alkaline dry battery having a gasket interposed between the opening of the positive electrode can and the negative electrode terminal plate and sealing between the two, the gasket is formed from nylon resin. A plurality of protrusions are formed on the surface of the relatively thin portion of the gasket, and the gasket is in contact with the inner surface of the negative electrode terminal plate via the protrusions.
[0008]
As a result, the potassium ions in the electrolyte in the dry battery only permeate the nylon gasket at the narrow protrusions that contact the inner surface of the negative electrode terminal plate. Liquid leakage can be prevented.
[0009]
Preferably, the relatively thin portion of the gasket is integrally formed between a central boss portion and an outer peripheral rising portion of the gasket, and the protrusion is a chevron-shaped protrusion of the annular protrusion of the relatively thin portion. It is formed on the upper surface and / or the outer peripheral bottom thereof.
[0010]
As a result, the portion where potassium ions permeate the nylon gasket is only the upper end portion of the extremely narrow chevron projection, so that leakage of the electrolyte can be further reduced.
[0011]
Further preferably, the total value of the circumferential widths of the plurality of protrusions in the gasket is 3.0% or less of the circumferential length of the gasket in the portion. As a result, the amount of potassium ions permeating through the nylon gasket is extremely small, and leakage of the electrolyte solution to the surface of the terminal board can be almost eliminated.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an alkaline battery of the present invention, and a negative electrode gel 2 in which an alkaline electrolyte composed of zinc powder, polyacrylic acid and potassium hydroxide is mixed in a known ratio at the inner central portion of a bottomed positive electrode can 1. The positive electrode mixture 4 is disposed on the outer periphery via a separator 3. The positive electrode mixture 4 is obtained by mixing and granulating electrolytic manganese dioxide, graphite, and an alkaline electrolytic solution made of potassium hydroxide, then forming a ring shape and press-fitting it into the positive electrode can 1.
[0013]
The open end of the positive electrode can 1 is sealed with a negative electrode terminal plate 6 made of a stainless steel plate via a nylon gasket 5. More specifically, a rod-shaped current collector 7 is integrally coupled to the lower surface of the center of the negative electrode terminal plate 6 by welding, and the central boss portion 5a of the gasket 5 is closely fitted to the upper end of the current collector. Yes. A gas discharge port 6 a is formed in the inclined outer peripheral edge of the negative electrode terminal plate 6. The outer peripheral rising portion 5 b of the gasket 5 is pressure-bonded so as to cover the outer peripheral end portion of the negative electrode terminal plate 6 by the open end 1 a crimped in a curled shape of the positive electrode can 1. A metal label 8 is bonded to the outer peripheral body of the positive electrode can 1.
[0014]
As shown in FIG. 2, the outer periphery of the central boss portion 5a is formed as an explosion-proof thin portion 5c. The thin portion 5c is formed when the internal pressure of the battery rises abnormally due to misuse of the battery. It is designed to be thick enough to burst. An outer peripheral rising portion 5b is integrally formed through a relatively thin horizontal inner peripheral bottom portion 5d, an annular convex portion 5e, and a horizontal outer peripheral bottom portion 5f from the thin explosion-proof portion 5c toward the outer peripheral side.
[0015]
Six first chevron protrusions 5g are integrally formed on the upper surface of the annular convex portion 5e of the gasket 5 at equal intervals in the circumferential direction, and eight second chevron shapes are formed on the upper surface of the outer peripheral bottom portion 5f. The protrusion 5h is integrally formed.
[0016]
In the state where such a gasket 5 is incorporated in the negative electrode terminal plate 6, as is clear from FIG. 1, the upper end of the first chevron 5 g of the annular projection 5 e of the gasket 5 is flat inside the negative electrode terminal plate 6. The second chevron 5g of the outer peripheral bottom 5f is in contact with the bottom 6c curved in a U shape at the outer peripheral edge of the negative terminal plate 6. The upper end surface of the boss portion 5a of the gasket 5 is also in contact with the center inner bottom surface of the negative electrode terminal plate.
[0017]
When a dry battery with a configuration in which a nylon gasket is in direct contact with the negative electrode terminal plate is stored in a high-temperature, high-humidity environment, apart from the thick boss portion of the gasket, the boss portion where the gasket contacts the negative electrode terminal plate In the relatively thin part of the outer periphery, potassium ions in the electrolyte solution made of potassium hydroxide permeate through the nylon gasket, and the potassium ions appear on the outer surface along the inner surface of the negative electrode terminal plate and combine with moisture to bind to the electrolyte solution. Leakage phenomenon occurs.
[0018]
However, in the dry battery of the present invention, the gasket is only the upper end surface of the first chevron protrusion 5g and the second chevron protrusion 5h, except for the thick boss part 5a and the outer peripheral rising part 5b. The amount of potassium ions permeating through the nylon gasket 5 is extremely small, and the leakage of the electrolyte solution to the negative electrode terminal plate surface can be substantially prevented.
[0019]
Next, the correlation between the width of the chevron protrusion and the leakage of the electrolyte to the outer surface of the negative electrode terminal plate was confirmed by experiments. In this experiment, in order to facilitate the confirmation of the correlation, the first protrusion 5g of the annular convex portion of the nylon gasket is not directly in contact with the inner bottom surface of the negative electrode terminal plate 6, and the eight outer peripheral bottom portions are in contact with each other. Only the second protrusion 5 h (excluding the boss portion 5 a and the outer peripheral rising portion 5 b) was in contact with the inner bottom surface of the negative electrode terminal plate 6. As shown in FIG. 3, the ratio (L × 8) of the total width (L × 8) of the upper end of the second protrusion 5h contacting the negative terminal plate 6 and the circumferential length 2πr passing through the center of the protrusion 5h ((L × 8) / 2πr) was varied and the number of leaks on the surface of the negative electrode terminal plate was counted over time. The results are shown in Table 1. The number of samples was 40.
[0020]
[Table 1]

[0021]
From the above experimental results, it is possible to reduce the number of leaks on the surface of the negative electrode terminal plate by reducing the width of the protrusion. Preferably, the total value of the protrusion width is 3 with respect to the total circumferential length passing through the protrusion. 0.0% or less.
[0022]
【The invention's effect】
According to the present invention, the potassium ions in the electrolyte solution in the dry battery only permeate the nylon gasket at the narrow protrusions that contact the inner surface of the negative terminal plate. It is possible to prevent leakage of the electrolyte into the battery.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an alkaline battery of the present invention.
FIG. 2 is a perspective view showing a nylon gasket applied to an alkaline battery of the present invention.
FIG. 3 is an explanatory diagram showing the width and circumference of a protrusion of a gasket used in an experiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Positive electrode can 2 Negative electrode gel 3 Separator 4 Positive electrode mixture 5 Gasket 5a Boss part 5b Rising part 5c Thin part 5d Inner peripheral bottom part 5e Annular convex part 5f Outer peripheral bottom part 5g First chevron protrusion 5h Second chevron protrusion 6 Negative terminal board 7 Current collector 8 Metal label

Claims (4)

In an alkaline battery having a gasket interposed between an opening of a positive electrode can and a negative electrode terminal plate and sealing between the two, the gasket is formed from nylon resin and is formed on the surface of a relatively thin portion of the gasket. An alkaline dry battery comprising a plurality of protrusions, and the gasket being in contact with the inner surface of the negative electrode terminal plate through the protrusions. The relatively thin portion of the gasket is integrally formed between a central boss portion and an outer peripheral rising portion of the gasket, and the protrusion is a chevron-like protrusion, and the upper surface of the annular protrusion of the relatively thin portion and / or The alkaline dry battery according to claim 1, wherein the alkaline dry battery is formed at the bottom of the outer periphery. 3. The alkaline dry battery according to claim 1, wherein a total width value in a circumferential direction of the plurality of protrusions in the gasket is 3.0% or less of a circumferential length of the gasket in the portion. The alkaline dry battery according to any one of claims 1 to 3, wherein six or more protrusions are formed at equal intervals in a circumferential direction of the gasket.

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