JP3176572B2 - Alkaline battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alkaline battery having a structure in which an open end of an electrode can is sealed by a gasket, and in particular, a stress applied to the open end when the gasket is sealed is applied to the gasket. The present invention relates to a technique for minimizing the effect on a thin-walled portion serving as an explosion-proof valve.

[0002]

2. Description of the Related Art In an alkaline battery, a large amount of gas may be generated inside due to overcharging or short-circuiting, which may lead to deformation or rupture. Explosion-proof mechanism is provided to release gas to the outside of the battery when the value of.

FIG. 7 shows an example of an LR6 type alkaline battery provided with this explosion-proof mechanism. As shown in the figure, in this battery, a negative electrode terminal plate (electrode plate) 17 is fitted through a gasket 15 to an open end 13 of a positive electrode can 3 having a bottomed cylindrical shape,
The opening end 13 is compressed and deformed from the outside to form a sealing structure in which caulking is performed. A boss 21 through which the current collector 11 is inserted is provided at the center of the gasket 15, and a thin portion 23 functioning as an explosion-proof valve is formed outside the boss 21. Is reached, the thin portion 23 breaks at the joint with the boss portion 21 to allow gas to escape therefrom.

FIG. 8 is an enlarged view showing the structure around the opening end 13. A metal ring 63 is fitted between the cylindrical outer peripheral portion 29 and the boss portion 21, and a gas vent hole 61 is formed in the metal ring 63. The outer edge of the negative electrode terminal plate 17 is folded back in an L-shape, and a gas vent hole 65 is formed in the cylindrical side surface.

The metal ring 63 is attached to the gasket 15 as a reaction force receiving member for compressive force due to caulking, and the metal ring 63 has a predetermined shape so that stress due to the compressive force is not generated in the thin portion 23. This is to ensure that the explosion-proof valve functions at the operating pressure of.

[0006]

However, in the conventional alkaline battery provided with the metal ring 63, an extra step of manufacturing the metal ring 63 is required, and the metal parts are generally expensive. Use of such a metal ring 63 is not desirable in terms of cost and work efficiency.

Therefore, the present inventors prototyped an alkaline battery having a sealing structure as shown in FIG. 5 in order to eliminate the metal ring 63 and reduce the number of parts. That is, in this sealing structure, the outer peripheral portion of the negative electrode terminal plate 17 is bent into a U-shape to form an annular reinforcing portion, and the cylinder of the gasket 15 is formed between the outer peripheral surface of the reinforcing portion and the opening end 13 of the battery can. Outer peripheral part 2
9 is pressed and compressed.

However, it has been found that such a sealing structure has the following problems. As shown in FIG.
Then, the negative electrode terminal plate 17 is set, and in this state, the opening end 13 is compressed radially inward to reduce the diameter, and the tip of the opening end 13 is bent inward. By this caulking, the thickness C of the cylindrical outer peripheral portion 29 before the caulking shown in the figure becomes the thickness D as shown in FIG. Although it is compressed, the strength of the reinforcing portion is not sufficiently obtained, so that stress is applied to the thin portion 23 of the gasket 15 so that the shape of the thin portion 23 is deformed as shown in FIG. Stress remains, and the influence of the residual stress causes a deviation in the above-described operating pressure.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to be able to seal with a minimum component configuration without using a reinforcing component such as a metal ring, and at the time of caulking. It is an object of the present invention to provide an alkaline battery in which stress does not affect the operating pressure of an explosion-proof valve provided on a gasket.

[0010]

In order to achieve the above object, according to the present invention, a current collector is press-fitted into an open end portion of a bottomed cylindrical electrode can in which a power generating element is inserted to form one pole. The electrode plate of the other electrode is fitted through a resin gasket having a boss portion to be penetrated and a cylindrical outer peripheral portion, and the cylindrical outer peripheral portion of the gasket is formed between the electrode plate and the electrode plate by caulking the open end. An alkaline battery provided with a thin portion which functions as an explosion-proof valve by breaking when the internal pressure of the can rises above a predetermined value. Inside the cylindrical outer periphery,
A buffer portion for absorbing the compressive force by deformation is provided, and a support portion which is sufficiently thicker than the thin portion is provided between the buffer portion and the thin portion.

With such a configuration, the effect of the stress generated at the time of caulking on the thin portion can be minimized by the cushion effect due to the deformation of the buffer portion and the reinforcing effect by the thick support portion. . (Claim 1) Here, the electrode plate has a folded portion having a substantially U-shaped cross section formed in an annular shape at an outer peripheral edge thereof, and the cylindrical outer peripheral portion of the gasket is folded back with the opening end. By adopting a configuration in which the outer peripheral portion of the electrode plate is pressed and compressed, the outer peripheral portion of the electrode plate can be reinforced and a sufficient sealing surface can be secured on the outer peripheral side surface. (Claim 2) In addition, the support portion is brought into contact with a protruding end surface of the folded portion,
The explosion-proof valve working space is defined between the thin portion and the electrode plate (Claim 3). More preferably, the distance between the thin portion defining the working space and the electrode plate is such that the thin portion is explosion-proof. If the thin-walled portion functions as an explosion-proof valve, the broken portion contacts the electrode plate to block the gas flow path. Can be prevented as much as possible. (Claim 4) Still further, if a gas vent hole is formed in the protruding end surface and a gas vent groove communicating with the working space and the gas vent hole is formed in the support portion, the inside of the working space can be reduced. Gas can be discharged smoothly to the outside of the battery. (Claim 5)

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the alkaline battery according to the present invention will be described below in detail with reference to the accompanying drawings. In the following description, the same members as those of the above-described conventional example are denoted by the same reference numerals.

FIG. 1 is a sectional view of an LR6 type alkaline battery. A cylindrical separator 5 is provided inside the metal positive electrode can 3.
Is inserted between the positive electrode can 3 and the separator 5, and the negative electrode active material 9 is provided inside the separator 5.
Is loaded. A current collector 11 is inserted into the negative electrode active material 9, and one end of the current collector 11 is connected to the open end 1 of the positive electrode can 3.
Gasket 15 that seals the gasket 3
Metallic negative electrode terminal plate (electrode plate) 17 that covers the outer side
Is in contact with The outer peripheral edge of the negative electrode terminal plate 17 is fitted to the open end of the positive electrode can 3 via a gasket, and the open end is held by caulking. The outside of the positive electrode can 3 is wrapped with a label 19 for exterior use.

FIG. 2 is a sectional view of the periphery of the opening end 13 which is a main part of the present invention. The gasket 15 is made of a resin obtained by injection molding a nylon-based resin such as 66 nylon, an amide-based resin, a propylene-based resin, or the like. The gasket 15 is formed with a boss 21 having a through hole for the current collector 11 in the center.

An annular thin portion 23 is provided around the boss 21.
Are formed. The cross section of the thin portion 23 is tapered such that the thickness increases toward the outside, and the joint portion 31 between the thin portion 23 and the boss portion 21 is the thinnest. When a large amount of gas is generated inside the battery, the joint portion 31 breaks and discharges the gas to the outside of the battery. That is, the thin portion 23 has a function as an explosion-proof valve.

An annularly thick supporting portion 25 is formed on the outer periphery of the thin portion 23 so as to be continuous with the thin portion 23. Thin part 23
The thickness of the support portion 25 is the same at the joint. The upper surface (inside of the can) of the support portion 25 has a slope shape that becomes higher toward the outer peripheral side. Further, a convex portion 33 protruding downward (outside of the can) is formed annularly below the support portion 25. Since the thickly reinforced support portion 25 is formed annularly on the outer periphery of the thin portion 23 in this manner, the compressive force inward in the radial direction due to the caulking process is compressed by the support portion 25 in the circumferential direction. , And the stress transmitted to the thin portion 23 is suppressed.

An annular buffer portion 27 is provided on the outer periphery of the support portion 25 along the annular shape, and a cylindrical outer peripheral portion 29 is formed on the outermost outer periphery of the buffer portion 27 via the buffer portion 27. The cushioning portion 27 is provided between the outer peripheral edge of the upper surface of the support portion 25 and the cylindrical outer peripheral portion 29.
Is formed in a conical cylindrical body whose upper side is reduced in diameter by connecting to the upper end (inner end of the can), and a gap having an inverted V-shaped cross section is opened between the support portion 25 and the support portion 25. I have. Further, the connecting portion with the supporting portion 25 is thin to make it easy to bend. On the other hand, a buffer portion 27 is joined to the cylindrical outer peripheral portion 29 on the inner peripheral surface at the upper end thereof, and an annular groove 28 is formed on the upper end surface along this joined portion. It is easy to bend. That is, the cushioning portion 27 functions as a hinge by deformation and absorbs the compressive force applied from the outer periphery side during caulking as a cushion, so that the stress transmitted from the cushioning portion 27 to the inner periphery side is reduced. It is attenuated significantly.

Further, the cylindrical outer peripheral portion 29 is formed to extend downward (outward of the can) from a joint portion with the buffer portion, and this extended portion is formed between the negative electrode terminal plate 17 and the positive electrode can 13 as described later. Sandwiched between. That is, the gasket 15
Is fixed to the alkaline battery by a cylindrical outer peripheral portion 29.

The negative electrode terminal plate 17 has, at its outer edge, a folded portion 34 having a substantially U-shaped cross section so as to protrude upward (inside of the can) in an annular shape. Present. The outer peripheral portion of the negative electrode terminal plate 17 is reinforced by the folded portion 34. Projecting end surface 43 of folded portion 34
The projection 33 of the support portion 25 is brought into contact with the support portion 25. The cylindrical outer peripheral portion 29 of the gasket 15 is pressed and compressed between the opening end portion 13 and the outer peripheral end surface 49 of the folded portion 34 by caulking. In addition, a ring-shaped insulating washer 47 that extends over the lower end of the positive electrode can 5 and covers the folded portion 34 is fitted to the outer peripheral wall surface on the small diameter side of the folded portion 34.

Further, the supporting portion 25 is in contact with the protruding end surface 43 of the folded portion 34, and the thin portion 23 and the negative electrode terminal plate 1 are contacted.
An explosion-proof valve working space 51 is defined between the space 7. Here, the distance between the thin portion 23 and the negative electrode terminal plate 17 is
If the lift amount is smaller than the maximum lift amount, the thin portion 23 may contact the negative electrode terminal plate 17 and block the gas flow path when operating as an explosion-proof valve. As shown in FIG. 3, the valve operating space 51 is formed such that the distance d between the thin portion 23 and the negative electrode terminal plate 17 is larger than the maximum lift L of the thin portion.

FIG. 4 shows a cross section taken along the line AA 'in FIG. 2. The gasket 15 is connected to the convex portion 33 so that the inverted V-shaped gap outside the support portion communicates with the explosion-proof valve working space inside. Gas vent grooves 53 are formed radially every 90 degrees along the circumference of the circle. In the protruding end surface 43 of the folded portion 34 of the negative electrode terminal plate 17, gas vent holes 45 are provided at appropriate positions facing the above-mentioned inverted V-shaped gap, and at two positions at 180 ° intervals in the present embodiment. I have. That is, the thin portion 23
The gas protruding from the inside of the battery after the joint portion 31 of the battery and the boss portion 21 breaks flows into the explosion-proof valve operating space 51, passes through the gas vent groove 53, and then has an inverted V-shaped gap and a gas vent hole 45. Sequentially flow out of the negative electrode terminal plate 17,
Further, the battery is discharged to the outside of the battery through a gap existing around the insulating washer 47.

Next, an alkaline battery according to the present invention, the above-described conventional alkaline battery, and an alkaline battery prototyped in a process prior to the present invention as a comparative example were prepared. And the explosion-proof performance during charging (the degree of securing a gas passage when the thin-walled portion was broken).

Table 1 shows the results of tests on the liquid leakage resistance and the explosion-proof performance during charging. The batteries used in the test were all LR6 cylindrical alkaline batteries. In the table, the number shown in the denominator indicates the number of batteries used for the test.

Here, in the liquid leakage resistance test, the caulked battery was stored in a high-temperature and high-humidity (60 ° C., 90% humidity) environment, and the thin-walled portions were obtained at 20, 40, and 60 days later. This was performed by counting the number of cells in which residual stress was confirmed (ie, the number of cells indicated in the numerator) in which the thin portion was cut by the stress and the internal liquid leaked. In addition, the explosion-proof performance test at the time of charging is performed in a room temperature environment by connecting one battery out of four batteries in series so that the polarities are opposite to each other, and setting a charged state.
The measurement was performed by counting the number of cells (the number shown in the numerator) for which a gas outflow path was not secured when a gas was generated inside the battery to break the joint between the thin portion and the boss.

[0025]

[Table 1] From the results shown in Table 1, it can be seen that the structure according to the example of the present invention has sufficient performance in both the leakage resistance property and the explosion-proof property at the time of charging without using a metal ring, which is inferior to that of the conventional example. Is found.

[0026]

As described above, in the alkaline battery of the present invention, a cushioning portion serving as a cushion for absorbing stress is provided inside the cylindrical outer peripheral portion of the gasket, and between the buffering portion and the thin portion. Since the annular support portion reinforced sufficiently thicker than the thin portion is provided, the stress transmitted from the outer peripheral side of the gasket by the caulking process is absorbed by the buffer portion and the support portion. Therefore, even without using a reinforcing part such as a metal ring,
The influence of the compressive stress caused by the caulking process on the thin portion can be minimized.

Further, the electrode plate has a folded portion having a substantially U-shaped cross section which is formed to project in an annular shape at an outer peripheral edge thereof, and the cylindrical outer peripheral portion of the gasket is connected to the open end and the outer periphery of the folded portion. By adopting a configuration that compresses and compresses with the side end surface,
The outer peripheral portion of the electrode plate can be reinforced and the sealing surface can be sufficiently secured.

Further, the support portion abuts on the protruding end face of the folded portion so that an explosion-proof valve operating space is defined between the thin portion and the electrode plate. The distance from the electrode plate is configured to be larger than the maximum lift when the thin portion functions as an explosion-proof valve, so that when the thin portion functions as an explosion-proof valve, the broken portion contacts the electrode plate. It is possible to prevent the gas flow path from being blocked.

Further, a gas vent hole is formed in the protruding end face, and a gas vent groove for communicating the working space and the gas vent hole is formed in the support portion, so that the inside of the working space is reduced. Gas can be smoothly discharged to the outside of the battery.

[Brief description of the drawings]

FIG. 1 is a view showing a longitudinal section of an alkaline battery according to one embodiment of the present invention.

FIG. 2 is a partially enlarged sectional view showing an open end of an alkaline battery according to an embodiment of the present invention.

FIG. 3 is a view showing a state in which a thin portion is broken and functions as an explosion-proof valve.

FIG. 4 shows one embodiment of the present invention,
It is a partial expanded sectional view of A 'part.

FIG. 5 is a partially enlarged cross-sectional view showing a state of an open end of an alkaline battery used as a comparative example.

FIG. 6A is a partially enlarged cross-sectional view showing a state of an opening end portion of an alkaline battery of a comparative example before caulking. (B) It is the elements on larger scale which show the state of the opening end part after the crimping process of the alkaline battery of a comparative example.

FIG. 7 is a view showing a longitudinal section of a conventional alkaline battery.

FIG. 8 is a partially enlarged sectional view showing an open end of a conventional alkaline battery.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 3 Positive electrode can 5 Separator 15 Gasket 17 Negative terminal plate 21 Boss 23 Thin part 25 Supporting part 27 Buffer part 29 Cylindrical outer peripheral part 51 Explosion-proof valve operation space

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-201865 (JP, A) JP-A-58-27859 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 2/02-2/08 H01M 2/12

Claims (5)

(57) [Claims] 1. A resin gasket having a boss portion for press-fitting and penetrating a current collector and a cylindrical outer peripheral portion is provided at an open end of a cylindrical electrode can having a bottom, in which a power generating element is inserted to form one pole. The other end of the gasket is fitted to the other end of the gasket, and the cylindrical outer peripheral portion of the gasket is pressed and compressed between the electrode plate and the electrode plate by caulking the open end to seal the open end. In an alkaline battery provided with a thin portion that functions as an explosion-proof valve by breaking when the internal pressure of the can rises above a predetermined value, a buffer that absorbs compressive force by deformation inside the cylindrical outer peripheral portion of the gasket. An alkaline battery, comprising: a support portion provided between the buffer portion and the thin portion; and a support portion sufficiently thicker than the thin portion. 2. An electrode plate according to claim 1, wherein said electrode plate has a bent portion having a substantially U-shaped cross-section formed in an annular shape at an outer peripheral edge thereof, wherein said cylindrical outer peripheral portion of said gasket has an open end of said electrode can and an electrode. 2. The alkaline battery according to claim 1, wherein the alkaline battery is pressed and compressed by the outer peripheral side surface of the folded portion of the plate. 3. A contact supporting portion of the gasket protruding end surface of the folded portion is brought, according to claim 2 in which explosion-proof valve working space between the thin portion and the electrode plate of the gasket is characterized in that it is defined alkaline battery according to. 4. The distance between the thin portion defining the explosion-proof valve working space and the electrode plate is greater than the maximum lift when the thin portion functions as an explosion-proof valve. 4. The alkaline battery according to 3 . 5. A gas vent hole is formed in the protruding end face,
5. The alkaline battery according to claim 3 , wherein a gas vent groove communicating the explosion-proof valve working space and the gas vent hole is formed in the support part. 6.