WO2003063268A1

WO2003063268A1 - Sealing gasket for alkali battery

Info

Publication number: WO2003063268A1
Application number: PCT/JP2003/000493
Authority: WO
Inventors: Takuji Ogawa; Hidenori Tsuzuki; Shuji Murakami; Katsuhiro Yamashita; Yoshiro Harada
Original assignee: Fdk Corporation
Priority date: 2002-01-21
Filing date: 2003-01-21
Publication date: 2003-07-31

Abstract

A sealing gasket installed between the positive pole can and the negative terminal plate of an alkali battery, comprising a cylindrical boss part fitted to a bar-like collector fixed to the center inner surface of the negative pole terminal plate, a thin-walled safety valve part formed around the boss part, a connection part facing from the safety valve part toward the outer peripheral end of the gasket, a buffer ring of reverse U-shape in cross section, a flat part in contact with the outer peripheral inner bottom surface of the negative pole terminal plate, and a tightening part crimped to the outer peripheral end of the negative pole terminal plate by the opening end of the positive pole can, wherein a passage part forming a vent part when the safety valve part is operated is formed at the outer peripheral part of the boss part on a side nearer the terminal plate than the safety valve part, a plurality of ribs are projectedly installed on the connection part on the negative pole terminal plate side along the circumferential direction thereof, and a plurality of circumferentially separated vent grooves are formed in the buffer ring.

Description

Itoda 口 Seal gasket for alkaline batteries

The present invention relates to a synthetic resin sealing gasket interposed between a positive electrode can and a negative electrode terminal plate of an alkaline battery.

Background technology

A conventional alkaline battery will be described with reference to FIGS. 8 and 9. The open end of the positive electrode can 2 of the alkaline battery 1 is sealed with the negative electrode terminal plate 3 through the gasket 6, and the negative electrode terminal plate 3 is closed. A gas outlet 4 is formed in the periphery, and the upper end of a rod-shaped current collector 5 is welded to the center of the inner surface. The gasket 6 has a cylindrical boss portion 61 fitted to the rod-shaped current collector 5, a thin safety valve portion 62 formed around the boss portion, and further from the safety valve portion 62 toward the outer peripheral end of the gasket. The connection part 63, a buffer ring 65 having an inverted U-shaped cross section, a flat part 66 contacting the inner bottom surface of the negative terminal plate, and the outer end of the negative terminal plate 3 are crimped by the open end of the positive electrode can. And a fastening portion 67.

The thickness of the safety valve portion 62 is set such that the safety valve portion 62 is broken when the pressure in the battery reaches a predetermined pressure in order to avoid rupture due to abnormal internal pressure due to misuse of the battery 1 or the like. Further, the buffer ring 65 having an inverted U-shaped cross section is formed so as not to apply a stress that would break the safety valve portion 62 when the battery 1 is assembled.

Then, when the internal pressure of the alkaline battery 1 increases and reaches a predetermined pressure, as shown in FIGS. 9A to 9C, the safety valve portion 62 of the sealing gasket 6 is broken, and the connecting portion 6 Since 3 is deformed in the direction of the internal pressure, gas escapes from the gap between the safety valve portion 62 and the boss portion 61, and the internal pressure is released through the discharge port 4.

However, such a structure had the following disadvantages. First, even if the safety valve section 62 breaks, the gap between the safety valve section 62 and the boss section 61 is originally narrow. Since the gas moves along the outer periphery of the boss portion 61, the gap between the safety valve portion 62 and the boss portion 61 is not so widened, so that the gas in the alkaline battery 1 cannot be sufficiently released. Secondly, since the connecting portion 63 finally comes into contact with the negative electrode terminal plate 2 and stops, gas escape is also prevented at this portion. Battery 1 may explode.

In view of such circumstances, the present invention provides a battery for an alkaline battery that can sufficiently release gas and, at the same time, can release an abnormal internal pressure immediately even if the gas flow rate is large to avoid rupture. It is intended to provide a sealing gasket. Disclosure of the invention

In order to achieve the above object, in the present invention, a passage portion which becomes a ventilation portion when the safety valve portion is operated is formed on an outer peripheral portion of the boss portion 61 closer to the terminal plate 3 than the safety valve portion 62. A plurality of lips are provided on the connecting portion 63 along the circumferential direction so as to protrude toward the negative electrode terminal plate, and a plurality of ventilation grooves are formed in the buffer ring 65 by being circumferentially separated. You.

A preferred method of forming the passage on the outer periphery of the boss 61 is to partially reduce the diameter of the boss.

By adopting such a configuration, when the internal pressure of the battery increases and the safety valve portion 62 is broken and the connecting portion 63 is deformed in the internal pressure direction, the broken portion of the safety valve portion 62 and the boss portion 61 become The gap between the ribs is sufficiently widened, and even if the ribs come into contact with the negative electrode terminal plate and stop, the gas acts to escape from the ventilation groove without interruption. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a partial cross-sectional view showing a portion on the negative electrode terminal plate side of an alkaline battery to which a sealing gasket according to a first embodiment of the present invention is assembled,

2 (a) to 2 (c) are perspective views showing three modified examples of the sealing gasket according to the first embodiment of the present invention,

FIGS. 3 (a) to 3 (c) are half sectional views showing the operating state of the safety valve portion of the sealing gasket shown in FIG. 1,

4 (a) to 4 (c) are perspective views showing three modified examples of the sealing gasket according to the second embodiment of the present invention. FIG. 5 is a partial cross-sectional view showing a part on the negative electrode terminal plate side of an alkaline battery to which a sealing gasket according to a second embodiment of the present invention is assembled,

FIG. 6 is a perspective view of a sealing gasket according to a third embodiment of the present invention,

FIG. 7 is an explanatory view of a gasket used for a performance test of a sealing gasket according to a third embodiment of the present invention,

FIG. 8 is a partial cross-sectional view showing a portion on the negative electrode terminal plate side of an alkaline battery in which a conventional sealing gasket is assembled,

9 (a) to 9 (c) are half sectional views showing the operating state of the safety valve portion of the conventional sealing gasket. BEST MODE FOR CARRYING OUT THE INVENTION

As shown in FIG. 1, the sealing gasket 6 according to the present invention is interposed between the open end of the positive electrode can 2 of the alkaline battery 1 and the negative electrode terminal plate 3, and is different from the conventional example. Similarly, a cylindrical boss part 61 fitted to the rod-shaped current collector 5, a thin safety valve part 62 formed around the boss part, and a safety valve part 62 from the outer peripheral end of the gasket. The connecting portion 63 toward the direction, the buffer ring 65 having an inverted U-shaped cross section, the flat portion 66 contacting the inner bottom surface of the negative electrode terminal plate, and the outer end of the negative electrode terminal plate 3 by the open end of the positive electrode can It has a fastening portion 67 to be crimped.

In the present invention, the outer peripheral portion above the boss portion 61, that is, from the safety valve portion 62, the negative terminal plate.

A passage portion 61a is formed in the outer peripheral portion of the third side edge by reducing the diameter of the portion, and a connecting portion 63 is formed as shown in FIG. 2 (a). The six ribs 64 protrude from the negative electrode terminal plate 2 side at equal angular intervals (60 ° intervals) on the circumference. The loose ring 65 has six ventilation grooves 65a formed at regular angular intervals (60 ° intervals) on the circumference. Here, the ribs 64 and the ventilation grooves 65a are arranged on the same straight line in the radial direction, and the circumferential width of each rib 64 is smaller than the circumferential width of each ventilation groove 65a. It is formed.

Since the sealing gasket 6 has the above configuration, when the internal pressure of the battery 1 rises and reaches a predetermined pressure, as shown in FIGS. 3 (a) to (c), Since the safety valve portion 62 of the sealing gasket 6 is broken and the connecting portion 63 is deformed toward the negative terminal plate 3, the gas escapes from the gap between the safety valve 62 and the boss portion 61 to release the internal pressure. At this time, The gap between the break portion of the safety valve portion 62 and the boss portion 61 is sufficiently ensured by the passage portion 61a having the boss portion reduced in diameter. In addition, the presence of the plurality of ribs 64 that are separated in the circumferential direction prevents the connecting portion 63 from completely contacting the inner surface of the negative electrode terminal plate 3 and blocking the gas discharge path as in the related art. Can move to the outer peripheral side of the negative electrode terminal plate. Even if the inverted U-shaped buffer ring 65 is pressed against the inner surface of the terminal plate 3 by internal pressure, a plurality of ventilation grooves 65 a are formed in the buffer ring so as to be separated in the circumferential direction. Therefore, the gas passes through the ventilation groove 65 a without interruption and is discharged from the exhaust port 4 formed in the outer peripheral portion of the terminal plate 3. Therefore, rupture due to abnormal internal pressure due to misuse of the alkaline battery 1 and the like can be avoided, and a highly safe alkaline battery 1 can be provided.

In the above-described embodiment, as shown in FIG. 2 (a), the force described for the sealing gasket 6 in which the ribs 64 and the ventilation grooves 65a are arranged on the same straight line in the radial direction. As shown in (b), the ribs 64 and the ventilation grooves 65a may be arranged on different radial lines. Alternatively, as shown in FIG. 2 (c), the number of the ribs 64 is reduced to three so that the circumferential spacing of these ribs 64 is made non-uniform, and some of the ribs 6 4 And a part of the ventilation groove 65 a are arranged on the same straight line in the radial direction, and-the remaining rib 64 and the remaining ventilation groove 65 a are arranged on different straight lines in the radial direction. It is also possible.

FIGS. 4 and 5 show a second embodiment of the present invention, this is Te ^second embodiment odors are changing heights of the plurality of ribs 6 4 of the first embodiment partially.

In FIG. 4 (a), the number of ribs 64 is four, and two adjacent ribs 64a of the four ribs are larger than the other two ribs 64b. The height in the direction of the negative electrode terminal plate from the base is increased. In this embodiment, the shape of the ribs 64 is a rectangular parallelepiped. However, the shape may be an arc as in the first embodiment.

The reason for changing the height of the lip in this way is that, for example, when the battery generates heat due to the reverse of the battery, the gasket softens and the internal pressure of the battery increases, and when the rib heights are all the same, The gasket is extended and the thin safety valve section 62 does not break, and the upper surface shown in the figure of the gasket approaches the negative terminal plate without breaking, and all the ribs 6 4 abut the lower surface of the negative terminal plate 3 at the same time. In this case, the flat surface of the connecting portion 63 between the ribs may be in close contact with the negative electrode terminal plate, and at the same time, the safety valve portion 62 may be broken. In such a case, the connecting portion 63 of the gasket 6 which is in close contact with the negative electrode terminal plate 3 makes the internal gas discharge passage. This will block the road and cause the battery to explode. On the other hand, as shown in FIGS. 4 (a) and 5, when the height of the ribs 64 is changed, the gasket softens and the internal pressure of the battery rises as described above, When the connecting portion 63 approaches the negative terminal plate, first, the high ribs 64a contact the inner surface of the terminal plate, and the further rise is stopped. On the other hand, since the lower rib 64b continues to rise further toward the terminal plate 3, the thin safety valve portion 62 between the high rib 64a and the low rib 64b is formed by the thinner rib. The rib 64b is pulled obliquely by the rise of the rib 64b, whereby the thin safety valve portion 62 is surely broken.

Therefore, by using this sealing gasket 1, an alkaline battery having high safety even at high temperatures can be assembled.

Even if the gasket connecting portion 63 around the low ribs 64b adheres tightly to the inner surface of the negative electrode terminal plate and blocks the gas escape path, the gas escapes from the opposite side (near the high rib 64b). Gas rupture due to misuse of a rechargeable battery or the like can be avoided.

In the embodiment described above, two ribs 64 a of the four ribs 64 are higher than the remaining two ribs 64 b, and these are arranged in the circumferential direction of the sealing gasket 1. The example in which the ribs are formed at equal intervals has been described. However, as shown in FIG. 4 (b), the angular intervals in the circumferential direction of the ribs 64a and 64b can be made nonuniform. Furthermore, as shown in FIG. 4 (c), one high rib 64a and one low rib 64b can be used. To confirm the above-mentioned effects, 40 prototypes of 9 types of AA alkaline batteries (Comparative Examples 1 and 2 and Examples 1 to 7) using various types of sealing gaskets 1 were manufactured at a temperature of 60. A series 24 hour continuous short test (hereinafter abbreviated as 4 direct test) and 8 series 24 hour continuous short test (hereinafter abbreviated as 8 direct test) were conducted. Table 1 summarizes the results.

Comparative example Example

Prototype No.

1 2 1 2 3 4 5 6 7 High 0 4 2 2 2 2 2 1 1 Number of ribs

Low 0 0 2 2

a 1 1 1 1 1 1 1.5 1 n

b 2 I 2 ί n 1 2 2 Lip dimension c 1 1 1 L 0.75 1 1 1 a 1 1

Low b 2 2

c 0.5 0.5. 75

c / d 0 1/3 1/3 1/3 1/3 1/4 1/3 1/3 1/3 Low rib / High rib Height 1/2 3/4

Negative terminal area 0 8 8 8 4 4 2 3 2

4 Direct test 10/40 4/40 0/40 0/40 0/40 0/40 0/40 0/40 0/40

8 Direct test 5/40 5/40 0/40 1/40 0/40 3/40 1/40 0/40 2/40 In Table 1, a is the width of the rib 64 in the circumferential direction (short side), b indicates the width (long side) of the rib in the radial direction, c indicates the height of the rib, and d indicates the distance from the base of the rib to the inner surface of the terminal plate as shown in FIG.

As is clear from Table 1, in Comparative Example 1 in which no ribs were formed, 10 out of 40 (25%) burst in the 4 direct test (including burst due to vapor pressure. The same applies hereinafter). However, 5 out of 40 pieces (12.5%) burst in the eight straight test. Also, in Comparative Example 2 in which four ribs having the same height were arranged at 90 ° intervals, four out of the 40 (10%) burst in the 4 direct test, and 8 in the 8 direct test. Five out of 40 (12.5%) burst. On the other hand, in Examples 1 and 2 in which two high ribs and two low ribs were mixed, none of the gas ruptures occurred in the 4-direct test, and it burst out of 40 in the 8-direct test. There were no more than one. In particular, in Example 1, in which the high ribs were twice as high as the low ribs, none of the eight straight tests had gas rupture.

Also, in Examples 3 to 7 in which one or two ribs were arranged at non-uniform angular intervals, there was no gas rupture in the 4 direct test, and 4 Less than three of the 0 ruptured. In particular, in Examples 3, 5 to 7 in which the height of at least one of the ribs was 1 Z 3 or more, which is the distance between the negative electrode terminal and the base of the rib, among the 40 in the 8 direct test, bursting occurred. Has been reduced to two or less.

As described above, according to the gasket for an alkaline dry battery according to the second embodiment of the present invention, when the sealing gasket is softened by heat, the high rib contacts the negative electrode terminal. The opposite side (near the lower rib) ensures that the safety valve breaks, and the connecting part of the gasket around the lower rib is in close contact with the inner surface of the negative electrode terminal plate and blocks the gas escape path. (Nearby) Since gas is released from the power, a sealing gasket for alkaline batteries that is highly safe even at high temperatures can be provided.

6 and 7 show a third embodiment of the present invention using a nylon resin as the sealing gasket.

Conventionally, in the case of a dry battery using a gasket made of NIPPON resin, a relatively thin portion of the gasket contacts the negative electrode terminal plate in a high-temperature and high-humidity environment at 75 ° C 90%. It has been known that when placed in R.H (Relative Humidity) for one week, leakage of electrolyte consisting of potassium hydroxide force occurs on the surface of the negative electrode terminal plate.

On the other hand, even if an alkaline dry battery using a gasket made of polypropylene and having the same other configuration as the above is stored for a long time in the same high-temperature and high-humidity environment as described above, the electrolytic solution composed of the hydroxide Does not leak to the surface of the negative electrode terminal plate.

Even in the case of a dry battery of the above configuration using a nylon gasket, the above-described liquid leakage does not occur when stored in a non-high-temperature, high-humidity environment (for example, dry at 75 ° C or normal temperature). Therefore, the present inventor has found that when a relatively thin portion of a gasket made of NIPPON absorbs moisture in a high-temperature and high-humidity environment, the calmion (K +) is connected to the negative terminal plate from inside the battery. At the contact area of the gasket, the gasket penetrates from the inner surface to the outer surface, and then travels along the outer surface of the gasket onto the negative electrode terminal plate and combines with moisture (OH-I) to cause a liquid leakage phenomenon (hydrational aqueous solution It was presumed that it would appear as (generation), and improvements were made.

In the nylon gasket 6 according to this embodiment, as shown in FIG. 6, a circumference is formed between the ventilation grooves 65 a on the upper surface of the inverted U-shaped buffer ring 65 on the side of the negative electrode terminal plate 3. Six first chevron projections 68 are formed at equal intervals in the direction, and eight second chevron projections are formed on the upper surface of the flat portion 66 contacting the inner bottom surface of the outer periphery of the negative electrode terminal plate 3. 69 are formed physically.

When a dry battery with a nylon gasket that comes into direct contact with the negative electrode terminal plate is stored in a high-temperature, high-humidity environment, the gasket will not contact the negative electrode terminal plate, except for the thick boss. In the relatively thin part of the outer periphery, potassium ions of the electrolytic solution consisting of a hydroxylating lime pass through a nylon gasket, On is transmitted along the inner surface of the negative electrode terminal plate and appears on the outer surface, and is combined with moisture to cause a leakage of the electrolyte.

However, in the dry battery according to the third embodiment of the present invention, the portion where the gasket contacts the negative electrode terminal plate except for the outer peripheral fastening portion 67 is only the upper end face of the first angle projection 68 and the second angle projection 69. Therefore, the amount of permeated ions passing through the nylon gasket 5 is extremely small, and leakage of the electrolytic solution to the surface of the negative electrode terminal plate can be substantially prevented. Next, the correlation between the width of the chevron and the leakage of electrolyte to the outer surface of the negative electrode terminal plate was confirmed by experiments. In this experiment, in order to make it easy to confirm the correlation, the first projection 68 of the buffer ring 65 of the gasket made of NIPPON was designed so that the first projection 68 did not directly contact the inner bottom surface of the negative electrode terminal plate 3. Only the eight second protrusions 69 of the flat portion 66 contacting the inner bottom of the terminal plate are in contact with the inner bottom surface of the negative terminal plate 3. Then, as shown in FIG. 7, the ratio of the total width L (LX 8) of the upper end of the second protrusion 69 abutting on the negative electrode terminal plate 3 (LX 8) to the circumference 2 π r passing through the center of the protrusion 69. ((LX 8) / 2π r) was varied and the number of liquid leaks on the surface of the negative electrode terminal plate was counted over time. The results are shown in Table 2. The number of samples was 40 each.

Table 2

From the above experimental results, it is possible to reduce the number of liquid leaks on the surface of the negative electrode terminal plate by reducing the width of the protrusion, and it is preferable that the total value of the protrusion width be equal to the total circumferential length passing through the protrusion. 3.0% or less. · That is, in the present embodiment, the gasket is formed of a resin, and a plurality of projections 69 are formed on the surface of a relatively thin portion of the gasket.

That is, the socket 6 comes into contact with the inner surface of the negative electrode terminal plate 3. As a result, since the force of the electrolyte solution in the dry battery only permeates the nylon gasket at the narrow projections that come into contact with the inner surface of the negative electrode terminal plate, the amount of the permeation is reduced and the electrolytic ions on the surface of the terminal plate are reduced. Liquid leakage can be prevented.

As described above, the sealing gasket for an alkaline battery of the present invention has been described based on the preferred embodiment of the present invention. However, the above-described embodiment of the present invention is for facilitating understanding of the present invention. Yes, and does not limit the present invention. Industrial applicability

In the present invention, when the internal pressure of the battery increases and the safety valve portion 62 is broken and the connecting portion 63 is deformed in the direction of the internal pressure, the gap between the broken portion of the safety valve portion 62 and the boss portion 61 is sufficiently widened. At the same time, even if the ribs 64 abut against the negative electrode terminal 3 plate and stop, the gas escapes from the ventilation groove 65 a force without interruption.

Claims

The scope of the claims

1. A sealing gasket interposed between the positive electrode can of the alkaline battery and the negative electrode terminal plate,

A cylindrical boss portion in which the gasket is fitted to a rod-shaped current collector fixed to a central inner surface of the negative electrode terminal plate; a thin safety valve portion formed around the boss portion; A negative electrode terminal by means of a connecting portion extending in the direction of the outer peripheral end of the gasket, a buffer ring having an inverted U-shaped cross section, a flat part in contact with the inner peripheral bottom surface of the negative electrode terminal plate, and an open end of the positive electrode can. And a clamping part to be crimped to the outer peripheral end of the plate,

A passage portion serving as a ventilation portion when the safety valve portion is operated is formed in an outer peripheral portion of the boss portion closer to the terminal plate than the safety valve portion;

A plurality of ribs are provided on the connecting portion along the circumferential direction to protrude toward the negative electrode terminal plate, and a plurality of ventilation grooves separated in the circumferential direction are formed on the buffer ring.

A sealing gasket for an alkaline battery.

2. The sealing gasket for an alkaline battery according to claim 1, wherein the circumferential width of each lip is smaller than the circumferential width of each ventilation groove.

3. The sealing gasket for an alkaline battery according to claim 1, wherein the rib and the ventilation groove are arranged on the same straight line in a radial direction.

3. The sealing gasket for an alkaline battery according to claim 1, wherein the rib and the ventilation groove are arranged on different straight lines in a radial direction.

5. A part of the ribs and a part of the ventilation grooves are arranged on the same straight line in the radial direction, and the remaining ribs and the remaining ventilation grooves are arranged on different straight lines in the radial direction. 3. The sealing gasket for an alkaline battery according to claim 1, wherein the sealing gasket is provided.

6. The sealing gasket for an alkaline battery according to claim 1, wherein the height of the plurality of ribs is changed to a plurality of heights.

7. The sealing gasket for an alkaline battery according to claim 6, wherein a height of the plurality of ribs is at least twice as high as a height of the low rib.

7. The sealing gasket for an alkaline battery according to claim 1, wherein a circumferential interval of the plurality of ribs arranged in a circumferential direction is made non-uniform.

9. The alkali according to claim 6, wherein a height of at least one lip of the plurality of ribs is set to 1 Z 3 or more as a distance between the negative electrode terminal plate and a base of the lip. Seal gasket for batteries.

10. The sealing gasket for an alkaline battery according to claim 6, wherein the area of the rib on the terminal plate side is 3 mm ² or more.

11. The gasket is formed of a nylon resin, and a plurality of small protrusions are formed on the surface of the flat portion of the gasket on the side of the terminal plate, and the gasket is formed on the inner surface of the terminal plate via the small protrusions. 7. The sealing gasket for an alkaline battery according to claim 1, wherein the sealing gasket is in contact with the sealing gasket.

12. A plurality of small projections are formed on the surface of the gasket on the terminal plate side of the buffer ring, and the buffer ring contacts the inner surface of the terminal plate via the small projections. 11. The sealing gasket for an alkaline battery according to claim 11, wherein

13. The total width value of the plurality of small projections in the gasket in the circumferential direction is not more than 3.0% of the circumferential length of the gasket in the portion. A sealing gasket for an alkaline battery as described above.

14. The sealing gasket for an alkaline battery according to claim 11, wherein the small projections are formed at equal intervals of 6 or more in a circumferential direction of the gasket.