JP7049865B2 - Alkaline batteries and methods for manufacturing alkaline batteries - Google Patents

Description

The present invention relates to an alkaline battery and a method for manufacturing an alkaline battery.

FIG. 1 shows an LR6 type cylindrical alkaline battery 1 as an example of a general conventional alkaline battery. FIG. 1 shows a vertical cross-sectional view when the extension direction of the cylindrical shaft 100 is the vertical (vertical) direction. As shown in FIG. 1, the alkaline battery 1 has a bottomed tubular metal battery can 2, an annularly formed positive electrode mixture 3, and a bottomed cylindrical shape arranged inside the positive electrode mixture 3. Separator 4, negative electrode gel 5 containing zinc alloy and filled inside the separator 4, metal negative electrode current collector 6 inserted in this negative electrode gel 5, dish-shaped metal negative electrode terminal plate 7, for sealing. It is composed of a gasket (hereinafter referred to as a gasket) 8 and the like.

Here, assuming that the vertical direction is defined with the bottom side of the battery can 2 facing downward, the battery can 2 also serves as a battery case and also serves as a positive electrode current collector by directly contacting the positive electrode mixture 3. Further, a positive electrode terminal 9 is formed on the bottom surface of the battery can 2. The dish-shaped negative electrode terminal plate 7 has a dish-shaped edge with a flange-shaped edge, and when the positive electrode terminal 9 is turned downward, the dish is crimped to the opening of the battery can 2 with the dish face down via a gasket 8. ..

The gasket 8 has a shape in which a disk-shaped partition wall portion 82 is formed around a hollow cylindrical boss portion 81 coaxial with the battery can 2, and the outer periphery of the partition wall portion 82 rises upward to form a wall surface portion 83. Has been done. The rod-shaped negative electrode current collector 6 inserted into the negative electrode gel 5 is inserted into the boss hole 84 that penetrates the boss portion 81 in the vertical direction. Further, the upper end 61 of the negative electrode current collector 6 is welded to the lower surface 71 of the dish-shaped negative electrode terminal plate 7 and fixed upright. The negative electrode terminal plate 7, the negative electrode current collector 6, and the gasket 8 are integrally combined in advance as a sealing body, and the wall surface portion 83 of the gasket 8 has a flange shape in the opening edge portion of the battery can 2 and the negative electrode terminal plate 7. The battery can 2 is sealed by being sandwiched between the edges of the battery can. The following Non-Patent Document 1 describes the basic structure and manufacturing procedure of an alkaline battery.

By the way, for example, a groove-shaped thin-walled portion 85 forming a concentric circle with the boss portion 81 is formed on the partition wall portion 82 of the gasket 8, and the inside and outside of the alkaline battery 1 are formed around the negative electrode terminal plate 7. A ventilation hole 72 is formed to connect the two. The thin portion 85 breaks when gas is generated in the battery can and the internal pressure rises, and the gas is discharged to the outside of the battery can 2 through the ventilation hole 72. This prevents the battery can 2 from bursting and the contents such as the negative electrode gel 5 from being ejected.

FDK Corporation, "Until the Alkaline Batteries are Made", [online], [Search January 24, 2018], Internet <URL: http://www.fdk.co.jp/denchi_club/denchi_story/arukari.htm ＞

In recent years, alkaline batteries have been required to have performance as a stockpile in the event of a disaster. That is, improvement in long-term storage performance is required. However, alkaline batteries are electrolyzed due to OH ^- ions generated when the moisture that has entered from the vent of the negative electrode terminal plate described above comes into contact with the upper end side of the negative electrode collector when the battery is stored for a long period of time. A phenomenon in which the liquid crawls up at the interface between the boss hole and the negative electrode current collector due to the capillary phenomenon, that is, a so-called creep phenomenon occurs. Then, the electrolytic solution that has creeped up to the upper end of the boss hole due to the creep phenomenon leaks to the outside of the battery can through the ventilation hole of the negative electrode terminal plate.

Therefore, an object of the present invention is to provide an alkaline battery having excellent long-term storage performance and a method for manufacturing the alkaline battery by suppressing liquid leakage caused by the creep phenomenon.

One aspect of the present invention for achieving the above object is an annular positive electrode mixture and a bottomed cylindrical battery arranged inside the positive electrode mixture in a bottomed cylindrical battery can with a lower bottom. This is an alkaline battery in which the separator and the negative electrode gel arranged inside the separator are housed together with the electrolytic solution, and the negative electrode terminal plate is fitted to the opening of the battery can via a gasket for sealing. hand,
A rod-shaped negative electrode collector attached to the lower surface of the negative electrode terminal plate coaxially with the battery can is provided.
The sealing gasket has a boss hole through which the negative electrode collector is inserted in a press-fitted state.
The negative electrode collector has a tapered shape in which the upper end of the negative electrode collector is reduced in diameter with respect to the lower end in the region inserted through the boss hole.
The opening diameter of the upper end of the boss hole is smaller than the opening diameter of the lower end.
It is an alkaline battery characterized by this.

It is preferable to use an alkaline battery in which the ratio of the opening diameter of the upper end to the opening diameter of the lower end of the boss hole and the ratio of the diameter of the upper end to the diameter of the lower end of the region of the negative electrode collector is 79% or less. An alkaline battery may be used in which the upper end of the negative electrode collector is welded to the lower surface of the negative electrode terminal plate and the diameter of the upper end of the negative electrode collector is 0.6 mm or more.

Another aspect of the present invention is the method for manufacturing an alkaline battery according to any one of the above.
The step of inserting the negative electrode collector into the boss hole from below,
A step of joining the upper end of the negative electrode collector and the lower surface of the negative electrode terminal board,
It is characterized by including.

According to the present invention, an alkaline battery having excellent long-term storage performance by suppressing the generation of liquid leakage due to a creep phenomenon at the interface between the boss hole of the gasket and the negative electrode current collector, and a method for manufacturing the alkaline battery are provided. Will be done. Other effects will be clarified by the following description.

It is a figure which shows the general alkaline battery. It is a figure which shows the alkaline battery which concerns on embodiment of this invention. It is an enlarged view of the main part of the alkaline battery which concerns on Example.

An embodiment of the present invention will be described below with reference to the accompanying drawings. In the following drawings used for the description, duplicate description may be omitted by assigning the same reference numerals to the same or similar parts. Further, depending on the drawing, unnecessary reference numerals may be omitted in the description.

=== Example ===
FIG. 2 shows a vertical cross section of the alkaline battery 1a according to the embodiment of the present invention. Further, FIG. 3 shows an enlarged view of the main part shown by the dotted rectangular area 101 in FIG. In addition, also in FIGS. 2 and 3, the upper and lower directions of the alkaline battery 1a are defined as in FIG. 1. As shown in FIG. 2, the basic configuration of the alkaline battery 1a is the same as that of the general alkaline battery 1 shown in FIG. That is, it includes a bottomed cylindrical battery can 2, a positive electrode mixture 3, a separator 4, a negative electrode gel 5, a negative electrode current collector 6a, a negative electrode terminal plate 7, and a gasket 8a. However, as shown in FIG. 3, in the alkaline battery 1a of the present embodiment, in the negative electrode current collector 6a, the region (hereinafter, also referred to as the insertion region) inserted through the boss hole 84a of the gasket 8a is shown in FIG. Unlike the general alkaline battery 1 shown, the upper part is formed in a tapered shape with a reduced diameter. In the alkaline battery 1a of the present embodiment, the portion 62 exposed upward from the insertion region of the negative electrode current collector 6a is cylindrical and reaches the upper end while maintaining the diameter A of the upper end of the insertion region. The upper end of the negative electrode current collector 6a is a flat surface.

The boss hole 84a through which the negative electrode collector 6a is inserted has an opening diameter on the upper end side reduced with respect to the opening diameter on the lower end side so as to follow the tapered shape in the insertion region of the negative electrode current collector 6a. That is, the interface where the boss hole 84a and the negative electrode current collector 6a come into contact with each other forms the side surface of the truncated cone with the lower portion as the bottom. The vertical cross section of the interface between the inner surface of the boss hole 84a and the negative electrode current collector 6a is an inclined straight line. On the other hand, in the general alkaline battery 1 shown in FIG. 1, the interface between the inner surface of the boss hole 84 and the negative electrode current collector 6 forms a side surface of a cylinder, and the vertical cross section of the inner surface of the boss hole 84 is a straight line in the vertical direction. It becomes. Since the negative electrode collector 6a is inserted into the boss hole 84a in a state of being press-fitted, the diameters of the upper end and the lower end of the boss hole 84a are the diameters B and the lower end of the upper end of the insertion region of the negative electrode collector 6a, respectively. Is smaller than the diameter A of.

Therefore, in the alkaline battery 1a of the present embodiment, the path through which the electrolytic solution crawls up from the lower end to the upper end of the boss hole 84a due to the creep phenomenon becomes long. For example, if the taper angle θ shown in FIG. 3 is 30 °, the crawling path is 2 / (√3) times as large as that of the boss hole 84 having a general cylindrical inner surface shape, which is about 15. %become longer. Then, if the crawling path becomes longer, the time required for the electrolytic solution to reach the upper end from the lower end of the boss hole 84a becomes longer as compared with the general alkaline battery 1. Further, since the upper end side of the boss hole 84a is reduced in diameter, the outlet of the electrolytic solution that crawls upward is narrowed, and the electrolytic solution is less likely to leak from the upper end of the boss hole 84a. As a result, leakage is less likely to occur.

Further, since the upper end of the negative electrode current collector 6a is reduced in diameter with respect to the lower end in the insertion region, it does not rise upward. Further, since the upper end of the negative electrode collector 6a is bonded to the lower surface 71 of the negative electrode terminal plate 7, the negative electrode collector 6a does not fall out of the boss hole 84a. In the alkaline battery 1a of the present embodiment, only the inner surface shape of the boss hole 84a and the shape of the upper end side of the negative electrode current collector 6a press-fitted into the boss hole 84a are different from the general alkaline battery 1. It does not increase the manufacturing cost.

When manufacturing the alkaline battery 1a of this embodiment, the negative electrode collector 6a is press-fitted from the lower end side of the boss hole 84a of the gasket 8, and the upper end of the negative electrode collector exposed on the upper end side of the boss portion is the negative electrode terminal. The sealing body may be assembled in advance by joining it to the lower surface of the plate by welding or the like. Then, after the positive electrode mixture 3, the separator 4, and the negative electrode gel 5 are stored in the battery can 2 and filled with the electrolytic solution, the sealing body is closed while the lower end side of the negative electrode current collector 6a is inserted into the negative electrode gel 5. It may be attached to the opening of the battery can 2 and the opening of the battery can 2 may be crimped to seal the battery can 2.

=== Long-term storage performance ===
<Sample>
In order to confirm the long-term storage performance of the alkaline battery 1a of the present embodiment described above, as a sample, a negative electrode collector 6a having a tapered insertion region and a tapered shape of each negative electrode collector 6a on the inner surface. An LR6 type alkaline battery (1, 1a) was manufactured using a gasket 8a provided with a boss hole 84a formed in a shape along the above. Here, as shown in FIG. 3, various samples having a diameter a at the upper end different from the diameter B at the lower end of the insertion region in the negative electrode current collector 6a were prepared. Further, as a comparative example, as shown in FIG. 1, a general LR6 type alkaline battery 1 having a diameter A and a diameter B of A = B was also produced as a sample. In addition, 100 individuals were prepared for each sample.

Table 1 below shows the sample preparation conditions.

表１において、サンプル１が比較例であり、Ａ＝Ｂ＝１．４ｍｍとなっている。サンプル２～９は、いずれもＢ＝１．４ｍｍと同一で、Ａ＜Ｂとなっている。また、表１では、負極集電子（６、６ａ）において、ボス孔（８４、８４ａ）に圧入されている領域の下端の径Ｂに対する上端の径Ａの比Ａ／Ｂが縮小率（％）として示されている。なお、各サンプルにおいて、ガスケット８ａのボス孔８４ａの下端の開口径に対する上端の開口径の比は、負極集電子６ａの縮小率に一致させている。

In Table 1, sample 1 is a comparative example, and A = B = 1.4 mm. Samples 2 to 9 are all the same as B = 1.4 mm, and A <B. Further, in Table 1, in the negative electrode collector (6, 6a), the ratio A / B of the diameter A of the upper end to the diameter B of the lower end of the region pressed into the boss hole (84, 84a) is the reduction ratio (%). It is shown as. In each sample, the ratio of the opening diameter of the upper end to the opening diameter of the lower end of the boss hole 84a of the gasket 8a matches the reduction rate of the negative electrode current collector 6a.

<Long-term storage test>
Each sample shown in Table 1 was subjected to a long-term storage test in which it was stored for 100 days in a high-temperature and high-humidity environment with a temperature of 60 ° C. and a humidity of 90%. The long-term storage performance was visually confirmed for the presence or absence of leaks every 10 days from the start of the test, and evaluated by the number of individuals in which leaks occurred.

Table 2 below shows the test results for each sample.

表２に示したように、比較例となるサンプル１では、試験開始から３０日経過後に、１本の個体に漏液が発生した。４０日経過後には漏液が発生した個体の累積個数が３本となった。そして、最終的に１００日後には漏液が発生した個体は１３本となった。

As shown in Table 2, in sample 1 as a comparative example, leakage occurred in one individual 30 days after the start of the test. After 40 days, the cumulative number of individuals with leaks reached three. Finally, after 100 days, the number of individuals in which leakage occurred was 13.

On the other hand, among the samples 2 to 9 provided with the tapered negative electrode collector 6a, in the sample 1 having the smallest taper angle and a reduction ratio of 93%, liquid leakage occurred 30 days after the start of the test. There was no individual. Leakage was confirmed in 2 individuals after 40 days, and finally 8 individuals had leakage after 100 days, indicating that the long-term storage performance was superior to that of Sample 1. In Sample 3 having a reduction rate of 86%, no leak occurred 70 days after the start of the test, and leak occurred in one individual on the 80th day. Even after 100 days, only two individuals leaked. In the samples 4 to 9 having a reduction ratio of 79% or less, no liquid leakage occurred in all the individuals even after 100 days had passed from the start of the test.

From the above test results, in the negative electrode collector, the tapered negative electrode collector whose upper end side is reduced in diameter in the region inserted through the boss hole and the opening diameter at the upper end are smaller than the opening diameter at the lower end. Alkaline batteries provided with boss holes are less likely to leak even when stored for a long period of time, and the above-mentioned alkaline batteries having a reduction ratio of 79% or less can reliably suppress leakage.

=== Other Examples ===
The reduction ratio is a ratio A / B of the diameters of the upper end side and the lower end side in the insertion region, and is a parameter that can be universally adopted even if the size of the alkaline battery 1a is deformed by a geometric progression. That is, the alkaline battery 1a according to the embodiment of the present invention is not limited to the LR6 type, but can be applied to alkaline batteries of other sizes (LR20 type, LR14 type, LR03 type, LR1 type, etc.) as long as it is a cylindrical type. Is.

Since the upper end of the insertion region is the outlet of the electrolytic solution that has crawled up due to the creep phenomenon, the smaller the diameter B of the upper end, the more difficult it is for liquid to leak. However, since the upper end of the negative electrode current collector 6a needs to be bonded to the lower surface of the negative electrode terminal plate 7, if the diameter 6 is too small, the bonding strength cannot be ensured. Then, when the present inventor tried to prepare a sample having a diameter of A <0.6 mm, it was found that the bonding strength was uncertain when A <0.6 mm. Therefore, when the upper end of the negative electrode current collector is joined to the lower surface of the negative electrode terminal plate by welding, it is desirable that the diameter A of the upper end of the insertion region is 0.6 mm or more.

Claims (4)

An annular positive electrode mixture, a bottomed cylindrical separator placed inside the positive electrode mixture, and a negative electrode gel placed inside the separator in a bottomed cylindrical battery can with the bottom as the bottom. Is an alkaline battery in which the negative electrode terminal plate is fitted together with the electrolytic solution in the opening of the battery can via a gasket for sealing.
A rod-shaped negative electrode collector attached to the lower surface of the negative electrode terminal plate coaxially with the battery can is provided.
The sealing gasket has a boss hole through which the negative electrode collector is inserted in a press-fitted state.
The negative electrode collector has a tapered shape in which the upper end of the negative electrode collector is reduced in diameter with respect to the lower end in the region inserted through the boss hole.
The opening diameter of the upper end of the boss hole is smaller than the opening diameter of the lower end.
Alkaline batteries that are characterized by that. In the alkaline battery according to claim 1, the ratio of the opening diameter of the upper end to the opening diameter of the lower end of the boss hole and the ratio of the diameter of the upper end to the diameter of the lower end of the region of the negative electrode current collector are 79% or less. Alkaline battery characterized by that. In the alkaline battery according to claim 1 or 2, the upper end of the negative electrode collector is welded to the lower surface of the negative electrode terminal plate, and the diameter of the upper end of the negative electrode collector is 0.6 mm or more. Alkaline battery featuring. The method for manufacturing an alkaline battery according to claim 1 to 3.
The step of inserting the negative electrode collector into the boss hole from below,
A step of joining the upper end of the negative electrode collector and the lower surface of the negative electrode terminal board,
A method for manufacturing an alkaline battery, which comprises.

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