JP2015225743A - Sealing gasket for alkaline battery and alkaline battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing gasket for alkaline battery capable of surely preventing a separator from bending, even if a stress buffer and the separator are not aligned strictly.SOLUTION: A sealing gasket being built in an alkaline battery 1a where a positive electrode mixture 3 and a negative electrode gel 5 are housed, via a separator, in a battery can 2 having an opening to which a negative electrode terminal plate 7 is fitted, and insulating the battery can and the negative electrode terminal plate, includes a disc-like barrier wall 23 having an outer peripheral part standing upward formed at the circumference, and a hollow cylindrical boss 21 for standing a negative electrode collector 6 in the center of the barrier wall. A round wall surface 40 is formed to project downward along the outer periphery of a stress buffer 30 formed in the barrier wall and bending downward, after inclining obliquely upward from the inner peripheral side toward the outer peripheral side. The lower surface of the stress buffer faces the separator, and a lower end 42 of the round wall surface 40 faces the upper end face of the positive electrode mixture, and located lower than the upper end of the separator.

Description

  The present invention relates to a technique for improving a sealing gasket constituting an alkaline battery.

  FIG. 1 shows the structure of a general LR6 type cylindrical alkaline battery 1, and FIG. 1 shows a longitudinal sectional view when the extending direction of the cylindrical shaft 100 is the vertical (vertical) direction. . As shown in the figure, the alkaline battery 1 includes a bottomed cylindrical metal battery can 2, a positive electrode mixture 3 formed in an annular shape, and a bottomed cylindrical separator 4 disposed inside the positive electrode mixture 3. A negative electrode gel 5 filled with zinc alloy inside the separator 4, a negative electrode current collector 6 made of a rod-like metal inserted in the negative electrode gel 5, a dish-shaped metal negative electrode terminal plate 7, and a resin. It is comprised by the sealing gasket 20 grade | etc.,. In this structure, the positive electrode mixture 3, the separator 4, and the negative electrode gel 5 form the power generation element of the alkaline battery 1 in the presence of the electrolytic solution. In the following, the vertical direction is defined with the bottom side of the battery can 2 as the lower side.

  The battery can 2 also serves as a battery case and also serves as a positive electrode current collector by being in direct contact with the positive electrode mixture 3, and a positive electrode terminal 8 is formed on the bottom surface of the battery can 2. The plate-like negative electrode terminal plate 7 has a plate shape with a flange-like edge. When the positive electrode terminal 8 is set downward, the plate-like negative electrode terminal plate 7 is caulked through the sealing gasket 20 in the opening of the battery can 2 with the plate down. Yes.

  The rod-shaped negative electrode current collector 6 inserted in the negative electrode gel 5 is fixed upright by welding its upper end to the lower surface of the dish-shaped negative electrode terminal plate 7. Note that the negative electrode terminal plate 7, the negative electrode current collector 6 and the gasket 20 are combined together in advance as a sealing body, and the sealing body is inserted into the battery can 2 and the opening of the battery can 2 is reduced inward. As a result, the gasket 20 is sandwiched between the opening edge of the battery can 2 and the flange-shaped edge of the negative electrode terminal plate 7, and the battery can 2 is sealed in a sealed state.

  FIG. 2 is a view showing the structure of the gasket 20, and here, the shape before being caulked in the opening of the battery can 2 is shown as a longitudinal sectional view. The gasket 20 has a cup shape around which a wall surface (hereinafter referred to as an outer peripheral portion) 24 erected upward around the disk. The center of the disk includes a hollow portion (boss hole) 22 into which the negative electrode current collector 6 is press-fitted. A cylindrical boss portion 21 is formed. The storage space for the power generation element in the battery can 2 is sealed by a film-like portion (hereinafter referred to as a partition wall portion) 23 extending from the outer periphery of the boss portion 21 to the periphery of the disk, and the inside of the battery can 2 is partitioned vertically. When assembling the alkaline battery 1, the negative electrode terminal plate 7, the negative electrode current collector 6, and the gasket 20 are combined in advance as a sealing body, and the sealing body is not a battery can 2 filled with a power generation element and an electrolytic solution. Insert into. When the opening of the battery can 2 is caulked, the outer peripheral portion 24 of the gasket 20 is sandwiched between the inner surface of the opening end side of the battery can 2 and the peripheral edge of the negative electrode terminal plate 7, and the inside of the battery can 2 is hermetically sealed. The

  By the way, the partition wall portion 23 of the sealing gasket 20 has concentric concavities and convexities. For example, a groove-shaped thin portion 25 is formed on a part of the surface of the partition wall portion 23. The thin-walled portion 25 is preliminarily broken when the pressure in the battery can 2 rises abnormally, and finally, the gas that caused the internal pressure is discharged into the exhaust hole 10 (FIG. 1) provided in the negative electrode terminal plate 7. It functions as an explosion-proof safety mechanism that opens to the atmosphere via

  Further, the partition wall portion 23 is provided with a stress buffer portion 30 that absorbs radial stress applied to the sealing gasket 20 when the opening of the battery can 2 is caulked during sealing. The stress buffer portion 30 has a buffer function that prevents the disk portion of the partition wall portion 23 from being uniformly deformed when stress is applied in the radial direction, or prevents the thin portion 25 from being inadvertently broken by the stress accompanying the reduced diameter. ing. And the buffer function by this stress buffer part 30 is brought about by the longitudinal cross-sectional shape of the partition part 23 of the sealing gasket 20, and in the sealing gasket 20 shown in FIG. The stress buffering portion 30 is a portion formed in a “h” shape that extends obliquely upward and then bends obliquely downward and reaches the outer peripheral portion 24 side. The stress buffer 30 absorbs the stress applied to the partition wall 23 by changing the angle θ of the bending point of the “U” character at the time of sealing. In addition, the stress buffer portion 30 forms a space 26 that is convex upward, and the upper end of the cylindrical separator 4 is disposed in the space 26. In addition, the structure of the sealing gasket provided with the stress buffer part is described in detail in the following Patent Document 1. Moreover, the manufacturing method of an alkaline battery is described in the following non-patent literature.

JP 2013-65459 A

FDK Corporation, “Until Alkaline Batteries”, [online], [Search April 28, 2014], Internet <URL: http://www.fdk.co.jp/denchi_club/denchi_story/arukari.htm >

  In the sealing gasket 20 shown in FIG. 2, the shape of the stress buffer portion 30 is optimized. When the opening of the battery can 2 is caulked and the battery can 2 is sealed, the sealing gasket 20 deforms. Deformation and breakage of the thin-walled portion 25 can be reliably prevented. And when it was assembled in the battery can 2, it had excellent impact resistance while securing the battery internal volume.

  However, since the stress buffer 30 is deformed during caulking, it is necessary to align the sealing gasket and the power generation element with high accuracy when the sealing gasket 20 is inserted into the battery can 2 in a state where the power generation element is accommodated. is there. In particular, when the positional relationship between the stress buffer portion 30 and the separator 4 is shifted, as shown in FIG. 3, the separator 4 deviates from the region of the stress buffer portion 30 when the stress buffer portion 30 is deformed, and the separator 4 May be bent. In such a case, the negative electrode gel 5 may leak out to the positive electrode mixture 3 side from the upper end portion 11 of the bent separator 4 as indicated by the arrow 12 in the figure, and an internal short circuit may occur. And the alkaline battery 1 which caused the internal short circuit at the time of an assembly will be processed as a defective product naturally.

  Therefore, the present invention is for an alkaline battery that can reliably prevent the bending of the separator and improve the production yield of the alkaline battery without strictly adjusting the positional relationship between the stress buffer portion and the separator during the assembly of the alkaline battery. The main object is to provide a sealing gasket and an alkaline battery equipped with the sealing gasket.

In order to achieve the above object, the present invention provides an annular positive electrode mixture and a bottomed cylindrical shape disposed inside the positive electrode mixture in a bottomed cylindrical battery can whose bottom is open at the bottom. And a negative electrode gel disposed inside the separator are housed as a power generation element, and are incorporated into an alkaline battery in which a negative electrode terminal plate is fitted into the opening of the battery can. A sealing gasket for insulating between the opening and the negative electrode terminal plate, the sealing gasket,
It is made of an integrally molded resin material, and a disc-shaped partition wall, an outer peripheral portion standing upward from the periphery of the partition wall, and a rod-shaped negative electrode current collector at the center of the disk-shaped partition wall And a boss part projecting in a hollow cylindrical shape in the vertical direction,
The partition wall portion is formed with a stress buffer portion that is inclined obliquely upward from the inner periphery side toward the outer periphery side and then bent downward, and along the outer periphery of the stress buffer portion on the lower surface of the partition wall portion. A circumferential wall surface portion protruding downward is formed,
The lower surface of the stress buffer portion is formed so as to be opposed to the upper end of the separator when incorporated in the alkaline battery,
The lower end of the circumferential wall surface portion is formed so as to face the upper end surface of the positive electrode mixture and to be positioned below the upper end of the separator when incorporated in the alkaline battery.
This is a sealing gasket for an alkaline battery.

  The ratio B / A between the distance A from the upper end surface of the positive electrode mixture to the upper end of the circumferential wall surface portion and the height B from the lower end to the upper end of the circumferential wall surface portion when incorporated in the alkaline battery. Is a sealing gasket for an alkaline battery formed so as to be 20% or more and 80% or less, or the circumferential wall surface portion is 0% in the circumferential direction when the circumferential length is 100%. More preferably, it is a sealing gasket for an alkaline battery in which a notch with a length of 15% or less is formed.

  Also, in the bottomed cylindrical battery can, an annular positive electrode mixture, a bottomed cylindrical separator arranged inside the positive electrode mixture, and a negative electrode gel arranged inside the separator are stored. In addition, an alkaline battery in which a negative electrode terminal plate is fitted into the opening of the battery can via the alkaline battery sealing gasket described above is also within the scope of the present invention. .

  According to the gasket for an alkaline battery of the present invention, it is possible to reliably prevent the separator from being bent at the time of assembling the battery without strictly adjusting the positional relationship between the stress buffer portion and the separator. And the alkaline battery provided with this sealing gasket has higher safety, has a high production yield, and can be provided at a lower cost.

It is a figure which shows the structure of a general alkaline battery. It is a figure which shows the structure of the conventional gasket integrated in the said general alkaline battery. It is a figure which shows the state which the separator bent in the said general alkaline battery. It is a figure which shows the structure of the sealing gasket which concerns on the 1st Example of this invention. It is a figure which shows the alkaline battery incorporating the sealing gasket which concerns on the said 1st Example. It is a figure which shows the arrangement | positioning relationship between the sealing gasket which concerns on the 2nd Example of this invention, and the positive mix in a battery can. It is a figure which shows the structure of the sealing gasket which concerns on the 3rd Example of this invention. It is a figure for demonstrating the appropriate size of the notch part with which the sealing gasket which concerns on the said 3rd Example is provided. It is a figure for demonstrating each part size of the sealing gasket which concerns on the said 3rd Example.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that in the drawings used for the following description, the same or similar parts may be denoted by the same reference numerals and redundant description may be omitted. In some drawings, unnecessary symbols may be omitted in the description.

=== First Embodiment ==
An alkaline battery sealing gasket (hereinafter also referred to as a gasket) according to a first embodiment of the present invention has a basic structure common to the following embodiments. FIG. 4 shows the structure of the gasket 20a according to the first embodiment. FIG. 4A is a longitudinal sectional view of the gasket 20a. (B) is a perspective view when the gasket 20a is viewed from below, and (C) is a perspective view when viewed from above. As shown in FIG. 4, the gasket 20 a of the present embodiment has a lower surface of the partition wall portion 23 along the outer periphery of the stress buffer portion 30 than the gasket 20 (hereinafter, comparative example) 20 shown in FIG. A wall surface projecting downward (hereinafter also referred to as a circumferential wall surface portion 40) is formed. In the example shown in FIG. 4, the circumferential wall surface portion 40 is formed in a cylindrical shape having an open lower end.

  FIG. 5 is a longitudinal sectional view of an alkaline battery 1a incorporating the gasket 20a of this embodiment. In the state of being incorporated in the alkaline battery 1 a, the lower end of the circumferential wall surface portion 40 faces the upper end surface 13 of the positive electrode mixture 3. That is, the separator 4 is disposed inside the circumferential wall surface portion 40. Since the inner circumference of the circumferential wall surface portion 40 is also the outer circumference of the stress buffer portion 30, the separator 4 is disposed inside the circumferential wall surface portion 40 when the gasket 20a is inserted into the battery can 2 when the alkaline battery 1a is assembled. You just have to make it. When the stress buffering portion 30 is deformed in the direction of reducing the diameter of the partition wall 23 when the battery can 2 is sealed, the outer peripheral surface on the upper end side of the separator 4 comes into contact with the inner peripheral surface of the rotating wall surface portion 40, and the separator 4 is always stressed. It stops in the area of the buffer 30. That is, the separator 4 does not deviate from the stress buffer 30 even if the alignment accuracy between the gasket 20a and the power generation element in the battery can 2 is low.

=== Second Embodiment ===
The gasket 20 a according to the first embodiment has a basic structure in which the lower end of the circumferential wall surface portion 40 faces the upper end surface 13 of the positive electrode mixture 3 in a state where the gasket 20 a is incorporated in the battery can 2. With this basic structure, the separator 4 can be reliably arranged in the region of the stress buffer portion 30 without performing precise alignment when assembling the alkaline battery 1a. However, on the other hand, when the gasket 20a is inserted into the battery can 2 when the alkaline battery 1a is assembled, or when the alkaline battery 1a is dropped, the upper end surface 13 of the positive electrode mixture 3 is brought into contact with the lower end of the circumferential wall portion 40, There is a possibility that a part of the positive electrode mixture 3 is lost due to the upper end surface 13 of the positive electrode mixture 3 being chipped or scraped. Deletion of a part of the positive electrode mixture 3 means that the power generation material is reduced, resulting in a reduction in discharge capacity. Further, it is conceivable to increase the distance between the lower end of the circumferential wall surface portion 40 and the upper end surface 13 of the positive electrode mixture 3 in order to prevent the loss of the positive electrode mixture 3, but if the distance is too large, for example, discharge When the filling amount of the negative electrode gel 5 is increased in order to increase the capacity, the liquid level of the negative electrode gel 5 becomes high. Therefore, when the negative electrode current collector 6 is inserted during assembly or when the alkaline battery 1a is dropped, the negative electrode gel 5 may overflow from the upper end of the separator 4 to the positive electrode side. Therefore, as a second embodiment of the present invention, a gasket having a structure for preventing the loss of the positive electrode mixture 3 and the outflow of the negative electrode gel 5 is given.

  FIG. 6 shows a schematic view of a gasket 20b according to the second embodiment. In this figure, a state where the gasket 20b is inserted into the battery can 2 is shown. In the gasket 20a according to the second embodiment, the circumferential wall surface portion 40 is used to prevent the separator 4 from being bent and to prevent the negative electrode mixture 3 from being lost and the negative electrode gel 5 from flowing out, as in the first embodiment. The ratio B / A of the height A from the lower end 42 to the upper end surface 13 of the positive electrode mixture 3 and the height B from the upper end 41 to the lower end 42 of the circumferential wall surface portion 40 is optimized. In this example, the lower end of the outer peripheral portion 24 is the upper end 41 of the rotating wall surface portion 40. And in order to obtain | require the optimal value of the B / A, the various gasket 20a from which the value of B / A differs was produced as a sample. And while dropping the negative electrode gel 5 to the lower end position of the boss | hub part 21, the drop test which drops each sample to the concrete surface 10 times from the height of 1 m with the negative electrode terminal side down was done. And the sample after a drop test was decomposed | disassembled and the defect | deletion state of the positive mix 3 was confirmed visually. The outflow state of the negative electrode gel 5 was also confirmed.

  Table 1 below shows the B / A values and the results of the drop test of the samples prepared.

表１では落下試験において、負極ゲル５の流出および正極合剤３の欠損の有無を×と○で示している。そして表１に示した結果よりＢ／Ａの値が２０％以上８０％以下であれば負極ゲル５の流出と正極合剤３の欠損をともに防止することができる。負極ゲル５の流出については周回壁面部４０の高さＢが低いとき（Ｂ／Ａ≦１０％）のときに発生し、正極合剤３の欠損については周回壁面部４０の下端４２と正極合剤３の上端面１３とが近接しているとき（Ｂ／Ａ≧９０％）に発生した。ここで上記のＢ／Ａの最適値をさらに詳しく調べるために、Ｂ／Ａの値をより細かく調整したサンプルを作製して同様の落下試験を行った。

In Table 1, in the drop test, the outflow of the negative electrode gel 5 and the presence or absence of the loss of the positive electrode mixture 3 are indicated by x and ◯. From the results shown in Table 1, both the outflow of the negative electrode gel 5 and the loss of the positive electrode mixture 3 can be prevented if the B / A value is 20% or more and 80% or less. The outflow of the negative electrode gel 5 occurs when the height B of the circumferential wall surface portion 40 is low (B / A ≦ 10%), and the loss of the positive electrode mixture 3 occurs between the lower end 42 of the circumferential wall surface portion 40 and the positive electrode combination. It occurred when the upper end surface 13 of the agent 3 was close (B / A ≧ 90%). Here, in order to investigate the optimum value of B / A in more detail, a sample in which the value of B / A was adjusted more finely was prepared and the same drop test was performed.

  Table 2 below shows the results of a detailed drop test.

表２に示した結果から、Ｂ／Ａの最適値が２０％≦Ｂ／Ａ≦８０％であることが確認できた。そして、周回壁面部４０をこの適正値の範囲内で形成すれば、正極合剤３の欠損を確実に防止でき負極ゲルを増量することができ、アルカリ電池の放電性能をより向上させることが可能となる。

From the results shown in Table 2, it was confirmed that the optimum value of B / A was 20% ≦ B / A ≦ 80%. And if the surrounding wall part 40 is formed within the range of this appropriate value, the loss of the positive electrode mixture 3 can be surely prevented, the amount of the negative electrode gel can be increased, and the discharge performance of the alkaline battery can be further improved. It becomes.

=== Third embodiment ===
As is well known, a gasket is an integrally molded product of resin, and as long as a mold is prepared, it can be manufactured in a single injection molding process regardless of the presence or absence of the circumferential wall surface 40, and there is a difference in manufacturing cost due to the difference in shape. almost none. Therefore, in order to reduce the manufacturing cost of the gasket, it is most effective to reduce the amount of resin used. Therefore, as a third embodiment of the present invention, a gasket capable of reducing the manufacturing cost by reducing the amount of resin used will be mentioned.

  FIG. 7 is a perspective view of the gasket 40c according to the third embodiment as viewed from below. As shown in FIG. 7, the circumferential wall surface portion 40 b is not a cylindrical shape with continuous side surfaces, and 43 types of cutout portions are formed in part. However, when the opening width C of the notch 43 is excessively increased in order to reduce the amount of resin, when an impact is applied, for example, when the alkaline battery falls in a state where the amount of filling of the negative electrode gel 5 is large, FIG. As described above, the upper end portion 11 of the separator 4 bends outward and deviates from the notch 43, and the negative electrode gel 5 may flow out from the deviated portion. Therefore, in order to prevent the deviation of the separator 4 while saving the amount of resin, it is necessary to appropriately set the opening width C of the notch 43.

  FIG. 9 is a diagram for explaining a concept for appropriately setting the opening width C of the notch 43. As shown in FIG. 9, when the circumferential length (L) of the circumferential wall surface portion 40 is 100%, the circumferential length of the notch 43 with respect to the circumferential length L (Opening width) Various alkaline batteries were produced using gaskets 20c having different C ratios C / L. And the drop test similar to the 2nd Example was done for the various alkaline batteries as a sample. The circumference L is obtained by a calculation formula of L = 2πr as a radius r from the center o of the disk-shaped gasket to the center of the thickness t of the circumferential wall surface portion, and the length C of the notch portion is the center angle of the notch portion. α (deg) is calculated based on the formula of C = 2πr · α / 360.

  Table 3 shows the relationship between the ratio of the length C of the notch to the circumference L and the result of the drop test.

表３に示した結果よりＣ／Ｌの値が２０％以上のときにセパレーターの変形が認められなかった。ここで上記のＣ／Ｌの最適値をさらに詳しく調べるために、Ｃ／Ｌの値をより細かく調整したサンプルを作製して同様の落下試験を行った。

From the results shown in Table 3, the separator was not deformed when the C / L value was 20% or more. Here, in order to investigate the optimum value of C / L in more detail, a sample in which the value of C / L was finely adjusted was prepared and the same drop test was performed.

  Table 4 below shows the results of a detailed drop test.

表４に示した結果から、Ｃ／Ｌの最適値がＣ／Ｌ≦１５％であることが確認できた。なお、切欠部４３の数については一つの切欠部４３が上記条件Ｃ／Ｌ≦１５％を満たす限り、いくつ設けてもよい。そして切欠部４３がＣ／Ｌ≦１５％の条件を満たせば、周回壁面部４０を備えたガスケット１ｃをより安価に製造することができるとともに、セパレーター４を周回壁面部４０の内方に確実に保持することができる。

From the results shown in Table 4, it was confirmed that the optimum value of C / L was C / L ≦ 15%. The number of cutouts 43 may be provided as long as one cutout 43 satisfies the above condition C / L ≦ 15%. And if the notch part 43 satisfy | fills the conditions of C / L <= 15%, while being able to manufacture the gasket 1c provided with the surrounding wall surface part 40 more cheaply, the separator 4 can be reliably inward of the surrounding wall surface part 40. Can be held.

1, 1a alkaline battery, 2 battery can (battery can), 3 positive electrode mixture, 4 separator,
5 negative gel, 6 negative current collector, 7 negative terminal plate, 8 positive terminal,
20, 20a-20c sealing gasket, 21 boss part, 22 boss hole,
23 partition part, 24 outer peripheral part, 25 thin part, 30 stress buffer part, 40 lap wall part,
43 Notch

Claims (4)

In a bottomed cylindrical battery can with the bottom at the bottom and open at the top, an annular positive electrode mixture, a bottomed cylindrical separator disposed inside the positive electrode mixture, and an inner side of the separator The negative electrode gel is housed as an electric power generation element, and is incorporated in an alkaline battery in which a negative electrode terminal plate is fitted into the opening of the battery can to insulate between the opening of the battery can and the negative electrode terminal plate. A sealing gasket for the sealing gasket,
It is made of an integrally molded resin material, and a disc-shaped partition wall, an outer peripheral portion standing upward from the periphery of the partition wall, and a rod-shaped negative electrode current collector at the center of the disk-shaped partition wall And a boss part projecting in a hollow cylindrical shape in the vertical direction,
The partition wall portion is formed with a stress buffer portion that is inclined obliquely upward from the inner periphery side toward the outer periphery side and then bent downward, and along the outer periphery of the stress buffer portion on the lower surface of the partition wall portion. A circumferential wall surface portion protruding downward is formed,
The lower surface of the stress buffer portion is formed so as to be opposed to the upper end of the separator when incorporated in the alkaline battery,
The lower end of the circumferential wall surface portion is formed so as to face the upper end surface of the positive electrode mixture and to be positioned below the upper end of the separator when incorporated in the alkaline battery.
A sealing gasket for alkaline batteries.   The distance A from the upper end surface of the positive electrode mixture to the upper end of the circumferential wall surface portion and the height B from the lower end to the upper end of the circumferential wall surface portion when incorporated in the alkaline battery according to claim 1. A sealing gasket for an alkaline battery, wherein the ratio B / A is 20% or more and 80% or less.   3. The notch having a length of not less than 0% and not more than 15% is formed in the circumferential direction of the circumferential wall surface portion when the circumferential length is 100%. A sealing gasket for alkaline batteries.   An annular positive electrode mixture, a bottomed cylindrical separator arranged inside the positive electrode mixture, and a negative electrode gel arranged inside the separator are housed in a bottomed cylindrical battery can. An alkaline battery, wherein a negative electrode terminal plate is fitted into the opening of the battery can through the sealing gasket for alkaline battery according to any one of claims 1 to 3.

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