JP2004281122A - Cylindrical alkaline battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently suppress a liquid leakage at a center boss portion of a resin-made gasket and enhance a liquid leakage resistance in a cylindrical alkaline battery having a structure in which a negative electrode current collector passes through the boss portion of the gasket. <P>SOLUTION: The battery is structured to make an uneven distribution state in which the stress operating between the center boss portion 34 of a gasket 33 and a negative electrode current collector 31 passing through the boss portion 34 becomes weak at the end portion on a power generation element 20 of the boss portion 34 and becomes stronger at an intermediate portion side which entered into a negative electrode terminal 32 side than at the end portion. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００２９】
上記表１からもあきらかなように、本発明では、アルカリ電解液と応力によるストレスクラックと、ボス部３４と集電子３１間におけるアルカリ電解液の這い上がりを、共に効果的に抑制することができる。
【００３０】
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、中央ボス部と負極集電子間に作用する応力が、そのボス部の発電要素側端部でゼロまたは小さく、その端部よりも負極端子側に入り込んだ中間部で大きくなるような不等分布状態は、集電子の外径を不等分布させることによっても可能である。
【００３１】
【発明の効果】
本発明によれば、負極集電子が樹脂製ガスケットの中央ボス部を貫通する構造を有する円筒型アルカリ電池において、その中央ボス部でのアルカリ電解液の漏液を効果的に抑制して耐漏液性を高めることができる。
【図面の簡単な説明】
【図１】本発明による円筒型アルカリ電池の一実施例を示す断面図である。
【図２】本発明の電池で使用されるガスケットとそのボス部での応力作用状態を示す断面図である。
【図３】本発明の電池で使用するガスケットの他の実施態様を例示する断面図である。
【図４】従来の円筒型アルカリ電池の構成を示す断面図である。
【図５】従来の電池で使用されていたガスケットとそのボス部での応力作用状態を示す断面図である。
【図６】従来のアルカリ電池で使用されていたガスケットとそのボス部での応力作用状態を示す断面図である。
【符号の説明】
１０ アルカリ電池（本発明）
１０’ アルカリ電池（従来）
１１ 電池缶
２０ 発電要素
２１ 正極合剤
２２ セパレータ
２３ 負極ゲル
３０ 封口体
３１ 集電子
３２ 負極端子
３３ ガスケット
３４ 中央ボス部（本発明）
３４’ 中央ボス部（従来）
３５ 挿通孔
３６ 隔壁部
３７ 周縁パッキング部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a cylindrical alkaline battery having a sealed structure, in particular, a structure in which a metal battery can also serving as a positive electrode terminal is sealed using a resin gasket, and a negative electrode current collector passes through a central boss portion of the gasket. It is effective to apply to
[0002]
[Prior art]
As a cylindrical alkaline battery, for example, an alkaline dry battery called by a model name such as LR20 (single) or LR6 (single) is typical. The configuration thereof is described in, for example, Japanese Patent Application Laid-Open No. H11-86810. No. 2000-3696.
[0003]
FIG. 4 shows a configuration example of a conventional cylindrical alkaline battery (alkaline dry battery). An alkaline battery 10 'shown in FIG. 1 has a bottomed cylindrical metal battery can 11 also serving as a positive electrode terminal, in which a power generating element 20 containing an alkaline electrolyte is accommodated, and an opening of the battery can 11 is formed as a negative electrode terminal 32. It is sealed using a resin gasket 33. The power generation element 20 is composed of a positive electrode mixture 21 formed into an annular shape and solidified, a separator 22 impregnated with an alkaline electrolyte, and a negative electrode gel 23. A rod-shaped negative electrode current collector 31 is inserted into the negative electrode gel 23. I have.
[0004]
The opening of the battery can 11 in which the power generating element 20 is stored is sealed by a sealing body 30. The sealing body 30 is a collective component in which the negative electrode current collector 31, the negative electrode terminal 32, and the gasket 33 are integrally combined in advance. After inserting this into the opening of the battery can 11, the opening is caulked. Thus, a sealing structure for hermetically sealing the battery can 11 is formed.
[0005]
The gasket 33 is a resin molded product such as polypropylene. The gasket 33 is interposed between the opening of the battery can 11 and the negative electrode terminal 32 in a pressed state and hermetically seals the opening. A partition wall portion 36 for isolating between a back space portion of the terminal 32 and a storage space portion of the power generation element 20, and a central boss through which a bar-shaped negative electrode current collector 31 erected on a back side surface of the negative electrode terminal 32 penetrates in a press-fit state. The part 34 'is integrally formed.
[0006]
The central boss portion 34 'has a columnar shape with a substantially uniform outer diameter, and an insertion hole 35 with a substantially uniform inner diameter is formed along the axis of the cylinder. The negative electrode current collector 31 is a straight rod having a circular cross section. The upper end is connected and fixed to the back side surface of the negative electrode terminal 32 by spot welding or the like, and the lower end is inserted into the negative electrode gel 23. The inner diameter of the insertion hole 35 is formed to be slightly smaller than the outer diameter of the current collector 31, so that the current collector 31 penetrates the boss 34 'in a press-fit state. This penetration in the press-fitted state prevents the alkaline electrolyte from creeping up and leaking at the penetrated portion.
[0007]
[Problems to be solved by the invention]
In the above-described alkaline battery, the ability of the alkaline battery to prevent leakage of the alkaline electrolyte, that is, leakage resistance is a problem. One of the factors inhibiting the leakage resistance is a crack in the gasket. The gasket is made of an electrically insulating and elastic resin such as polypropylene.However, if the gasket is in contact with an alkaline electrolyte for a long time, cracks may occur at the contact points of the electrolyte and cause leakage. is there.
[0008]
Conventionally, as described in Japanese Patent Application Laid-Open No. 2000-3696, for example, when a resin injection gate portion for forming a gasket is arranged to be in contact with an alkaline electrolyte, the gate portion is in contact with the alkaline electrolyte. It was said that the erosion was likely to cause the cracks. In the case of a gasket, the resin injection gate portion is disposed at the end of the central boss portion. However, if the gate portion is on the side of the power generation element exposed to the alkaline electrolyte, the crack is likely to occur. Therefore, Japanese Patent Application Laid-Open No. 2000-3696 proposes disposing the resin injection gate on the negative electrode terminal side, not on the power generation element side where the alkaline electrolyte is present. However, the crack does not necessarily occur only in the resin injection gate portion, and when exposed to the alkaline electrolyte for a long time in the presence of stress strain, contact with the alkali electrolyte does not occur even in the resin injection gate portion. Cracks may occur in some places, leading to liquid leakage.
[0009]
FIG. 5 shows the cross section (cut surface) shape of the gasket 33 used in the conventional alkaline battery and the state of stress (arrow) generated in the central boss portion 34 '. An insertion hole 35 is formed in the central boss 34 ′ of the gasket 33, and the negative electrode current collector 31 penetrates therethrough. This penetration is performed in a press-fit state, whereby a stress always acts between the central boss portion 34 ′ and the negative electrode current collector 31. The arrows in the figure indicate the direction and magnitude of the stress. The direction of the arrow indicates the direction in which the stress acts, and the length of the arrow indicates the magnitude of the stress. The stress of the central boss portion 34 'is distributed almost uniformly along the insertion hole 35. This stress is caused by the elastic strain of the gasket. When the stress strain portion is exposed to the alkaline electrolyte, cracks (a kind of stress crack) are generated regardless of the presence or absence of the resin injection gate portion, thereby causing liquid leakage. .
[0010]
In order to prevent the above-mentioned stress crack from occurring, it is necessary to reduce the stress strain at the boss portion 34 '. However, when the stress strain is reduced, the alkaline electrolyte is likely to crawl (bleed) between the boss portion 34 'and the current collector 31, and contradicting to a decrease in the leakage resistance.
[0011]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a cylindrical alkaline battery having a structure in which a negative electrode current collector penetrates a central boss of a resin gasket. An object of the present invention is to effectively suppress leakage of an electrolytic solution and increase leakage resistance.
[0012]
[Means for Solving the Problems]
Means according to the present invention is that a power generating element containing an alkaline electrolyte is accommodated in a bottomed cylindrical metal battery can also serving as a positive electrode terminal, and the opening of the battery can is sealed with a negative electrode terminal and a resin gasket, The gasket is provided between the opening and the negative electrode terminal in a pressed state to seal the opening tightly, a peripheral packing portion, a back space of the negative electrode terminal, and a storage space for the power generation element. In the cylindrical alkaline battery, a partition wall portion for isolating between the two and a central boss portion integrally formed with a bar-shaped negative electrode current collector standing on the back side surface of the negative electrode terminal for press-fitting therethrough are integrally formed. So that the stress acting between the negative electrode current collector and the boss portion is zero or smaller at the end of the power generation element side of the boss portion, and becomes larger at the intermediate portion that enters the negative electrode terminal side than the end portion so as to form an uneven distribution state. Make up It is characterized in.
[0013]
By the above means, the stress crack due to the alkaline electrolyte and the stress, and the rise of the alkaline electrolyte between the boss portion and the current collector can both be effectively suppressed, and the leakage resistance can be increased.
[0014]
In this case, by forming the inner diameter of the hole through which the negative electrode current collector penetrates through the boss portion so as to be smaller at the intermediate portion that enters the negative electrode terminal side than at the power generation element side end portion, the stress is not uniformly distributed. Can be formed. In addition, the unequal distribution of the stress can also be formed by forming the outer shape of the boss portion into a shape that expands in an arc shape between the end of the negative electrode terminal and the end of the power generation element.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows an embodiment of a cylindrical alkaline battery (alkaline dry battery) to which the technology according to the present invention is applied. The alkaline battery 10 shown in FIG. 1 has an overall basic configuration similar to that of the conventional battery described above, and includes a power generating element 20 containing an alkaline electrolyte in a bottomed cylindrical metal battery can 11 also serving as a positive electrode terminal. While being stored, the opening of the battery can 11 is sealed with a negative electrode terminal 32 and a resin gasket 33.
[0016]
The battery can 11 is formed by pressing a thin metal plate such as a nickel-plated thin steel plate or a nickel-iron alloy, and also serves as a positive electrode terminal. The power generating element 20 includes a positive electrode mixture 21, a separator 22, and a negative electrode gel 23, and a bar-shaped negative electrode current collector 31 is inserted into the negative electrode gel 23. The positive electrode mixture 21 is obtained by molding and solidifying a positive electrode active material containing manganese dioxide or the like in a ring shape, and is loaded into the battery can 11 in a press-fit state. The separator 22 is impregnated with an alkaline electrolyte. The negative electrode gel 23 is prepared by using gel zinc, and the current collector 31 is inserted into the gel.
[0017]
The opening of the battery can 11 in which the power generation element 20 is stored is closed by a sealing body 30. The sealing body 30 is a collective component in which the negative electrode current collector 31, the negative electrode terminal 32, and the gasket 33 are integrally combined in advance. After inserting this into the opening of the battery can 11, the opening is caulked. Thus, a sealing structure for hermetically sealing the battery can 11 is formed. The negative electrode terminal 32 is made of metal pressed into a dish shape, and the outer bottom surface of the dish forms a negative electrode terminal surface (front side surface).
[0018]
The gasket 33 is a resin molded product such as polypropylene. The gasket 33 is interposed between the opening of the battery can 11 and the negative electrode terminal 32 in a pressed state and hermetically seals the opening. A partition 36 for isolating the back side space of the terminal 32 from the storage space for the power generating element 20, and a central boss through which the bar-shaped negative electrode current collector 31 erected on the back side of the negative electrode terminal 32 penetrates in a press-fit state. The part 34 is formed integrally.
[0019]
Although not shown, the space on the back side of the negative electrode terminal 32 communicates with the outside at the same pressure by a gas vent hole. At the same time, a thin portion for explosion proof is formed in a part of the gasket 33, and when the internal pressure of the battery can 11 rises abnormally, the thin portion is broken to prevent the battery from bursting. .
[0020]
FIG. 2 shows a cross-sectional (cut surface) shape of the gasket 33 and a state of stress (arrow) generated in the central boss portion 34 thereof. An insertion hole 35 is formed in the central boss portion 34 of the gasket 33, and the negative electrode current collector 31 penetrates therethrough. This penetration is performed in a press-fit state, so that a stress always acts between the central boss portion 34 and the negative electrode current collector 31. The arrows in the figure indicate the direction and magnitude of the stress. The direction of the arrow indicates the direction in which the stress acts, and the length of the arrow indicates the magnitude of the stress.
[0021]
Here, the gasket 33 shown in the figure has a shape in which the outer shape of the boss portion 34 expands in an arc shape between the end on the negative electrode terminal 32 side and the end on the power generation element 20 side. Further, the inner diameter of the insertion hole 35 through which the negative electrode current collector 31 penetrates through the boss portion 34 is formed to be smaller at the intermediate portion that enters the negative electrode terminal 32 side than the end portion on the power generation element 20 side. In other words, the hole 35 is formed such that the inner diameter becomes maximum at the opening portions at both ends, and the inner diameter becomes minimum at the middle (center portion). As a result, the stress acting between the central boss portion 34 and the negative electrode current collector 31 is small at the end of the boss portion 34 on the power generation element 20 side, and is large at the intermediate portion that enters the negative electrode terminal 32 side from the end portion. It works in an uneven distribution state.
[0022]
According to the above-described configuration, the lower end portion (the end portion on the power generation element 20 side) of the boss portion 34 comes into contact with the alkaline electrolyte. Stress cracks are less likely to occur. On the other hand, in an intermediate portion (central portion) distant from the contact portion with the alkaline electrolyte, a necessary and sufficient stress acts to suppress the creeping of the alkaline electrolyte. Thereby, it is possible to effectively suppress both the stress crack due to the alkaline electrolyte and the stress and the rise of the alkaline electrolyte between the boss portion 34 and the current collector 31.
[0023]
FIG. 3 shows another embodiment of a gasket 33 useful for the present invention. The gasket structure for obtaining the above-described liquid leakage suppressing effect may be, for example, a cross-section (cut surface) structure shown in each of FIGS. In either structure, the stress acting between the central boss portion 34 and the negative electrode current collector 31 is small at the end of the boss portion 34 on the power generation element 20 side, and at the intermediate portion that enters the negative electrode terminal 32 side from the end portion. An unequal distribution state can be achieved, whereby the leakage of the alkaline electrolyte at the central boss portion 34 can be effectively suppressed, and the leakage resistance can be increased.
[0024]
The above-described gasket 33 is manufactured by resin molding using a mold. In the configuration of the present invention described above, the resin injection gate portion at the time of the molding is disposed at the end of the central boss portion 34 on the power generation element 20 side. It was confirmed that there was no particular problem. Hereinafter, the test results obtained by actually producing the alkaline batteries of the above-described examples are shown.
[0025]
<Test 1. >
== Crack generation test ==
LR20-type alkaline dry batteries were manufactured as prototypes according to the present invention and the conventional configuration, respectively, stored in a 90 ° C. constant temperature bath for 30 days, and then disassembled to observe the occurrence of stress cracks in the boss of the gasket.
[0026]
<Test 2. >
A battery having no negative electrode terminal was fabricated, and the number of days of exposure of the alkaline electrolyte at the negative electrode current collector at room temperature (the number of days the alkaline electrolyte crawled to the negative electrode side) was examined. The current collector used herein had a diameter of 2.0 mm in both the present invention and the conventional one.
[0027]
Table 1 below shows the results of Tests 1 and 2 above. In Table 1, Conventional Examples 1 to 3 are gaskets having a boss having a cross-sectional (cut surface) structure as shown in FIG. 5, and Conventional Example 4 is a boss having a cross-sectional (cut surface) structure as shown in FIG. A gasket having a portion was used. In addition, the present invention 1 is a gasket having a boss having a cross-sectional (cut surface) structure as shown in FIG. 3A, and the present inventions 2 and 3 are cross-sectional views as shown in FIGS. A gasket having a boss portion having a (cut surface) structure was used.
[0028]
[Table 1]

[0029]
As is apparent from Table 1 above, in the present invention, both the stress crack due to the alkaline electrolyte and the stress and the rise of the alkaline electrolyte between the boss portion 34 and the current collector 31 can be effectively suppressed. .
[0030]
As described above, the present invention has been described based on the typical embodiments, but the present invention can have various aspects other than the above. For example, the stress acting between the central boss and the negative electrode current collector is zero or smaller at the end of the boss on the power generating element side, and is larger at the intermediate part that enters the negative electrode terminal side than the end. The distribution state can also be achieved by making the outer diameter of the current collector uneven.
[0031]
【The invention's effect】
According to the present invention, in a cylindrical alkaline battery having a structure in which a negative electrode current collector penetrates a central boss portion of a resin gasket, leakage of an alkaline electrolyte at the central boss portion is effectively suppressed to prevent leakage. Can be enhanced.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an embodiment of a cylindrical alkaline battery according to the present invention.
FIG. 2 is a cross-sectional view showing a gasket used in the battery of the present invention and a stress acting state at a boss thereof.
FIG. 3 is a cross-sectional view illustrating another embodiment of the gasket used in the battery of the present invention.
FIG. 4 is a cross-sectional view showing a configuration of a conventional cylindrical alkaline battery.
FIG. 5 is a cross-sectional view showing a gasket used in a conventional battery and a stress acting state at a boss thereof.
FIG. 6 is a cross-sectional view showing a gasket used in a conventional alkaline battery and a stress acting state at a boss thereof.
[Explanation of symbols]
10. Alkaline battery (the present invention)
10 'alkaline battery (conventional)
Reference Signs List 11 battery can 20 power generating element 21 positive electrode mixture 22 separator 23 negative electrode gel 30 sealing body 31 current collector 32 negative electrode terminal 33 gasket 34 central boss (the present invention)
34 'center boss (conventional)
35 insertion hole 36 partition 37 peripheral packing

Claims (3)

A power generating element containing an alkaline electrolyte is accommodated in a bottomed cylindrical metal battery can also serving as a positive electrode terminal, and an opening of the battery can is sealed with a negative electrode terminal and a resin gasket. A peripheral packing portion interposed in a pressure-pressed state between the portion and the negative electrode terminal to hermetically seal the opening, and a partition wall for separating a space behind the negative electrode terminal and a space for accommodating the power generating element. And a central boss portion integrally formed with a central boss portion through which a rod-shaped negative electrode current collector erected on the back side surface of the negative electrode terminal is pressed in, in a cylindrical alkaline battery, wherein between the central boss portion and the negative electrode current collector The stress acting on the boss is zero or smaller at the end of the power generation element side of the boss portion, and it is configured to form an unequal distribution state in which the middle portion enters the negative electrode terminal side more than the end portion. Circle Type alkaline batteries. 2. The unevenness of the stress according to claim 1, wherein an inner diameter of a hole of the boss through which the negative electrode current collector penetrates is formed so as to be smaller at an intermediate portion that enters the negative electrode terminal side than at a power generating element side end. A cylindrical alkaline battery in which a distribution state is formed. 3. The cylindrical alkaline battery according to claim 1, wherein the outer shape of the boss portion is shaped to expand in an arc shape between the negative terminal side end and the power generating element side end.

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