JP2003157859A - Dry cell - Google Patents

Abstract

(57) [Summary] (with correction) [PROBLEMS] To provide a dry battery that can reliably prevent the occurrence of liquid leakage due to a decrease in the amount of sealant with a simple configuration that does not increase the cost. A positive electrode protrusion 1a serving as a positive electrode terminal is provided at the center of the bottom surface.
A hollow cylindrical positive electrode mixture 2 is accommodated in a battery case 1 formed in a bottomed cylindrical shape having a bottom, and a gelled negative electrode 8 is placed inside the positive electrode mixture 2 via a cylindrical separator 9. The battery case 1 is housed and the opening of the battery case 1 is sealed by a sealing body 10. The separator 9 is formed by winding a separator piece having a notch 17 in which at least the corner of the four corners of the rectangular shape on the side of the sealing body 10 at the end of winding is cut into a cylindrical shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to an alkaline dry battery having an inside-out structure in which a battery case as an outer casing is used as a positive electrode and a gelled negative electrode is filled therein.

[0002]

2. Description of the Related Art As shown in FIG. 6, such an alkaline dry battery has a hollow cylindrical metal battery case 1 in which a positive electrode convex portion 1a serving as a positive electrode terminal is integrally projectingly provided on the bottom. A plurality of positive electrode mixture 2 pressure-molded into a circular shape is loaded, and the separator 3 wound in a cylindrical shape is inserted into each positive electrode mixture 2 so as to be in contact with the inner peripheral surface thereof, and the separator 3
The cylindrical bottom opening of is sealed with a bottom separator 4, and a gelled negative electrode (not shown) is loaded into the internal space surrounded by the separator 3 and the bottom separator 4, and
An alkaline electrolyte (not shown) is injected, and the upper end opening of the battery case 1 is sealed by a sealing body (not shown) having both the functions of current collector and negative electrode terminal.

As shown in FIG. 1C, the separator 3 is formed by winding a rectangular separator piece, for example, made of a nonwoven fabric made of a cellulose-based or polyester-based chemical fiber into a winding number of 2 to 3 turns. And formed into a cylindrical shape, and then inserted into each positive electrode mixture 2. Further, in the battery case 1, an outer peripheral surface near the opening is grooved to form an annular groove 1b, and the annular groove 1b is provided with an annular supporting portion 1c bulging inward. There is. A sealing body is placed on and supported by the annular support portion 1c.

[0004]

By the way, in assembling the above alkaline dry battery, it is clearly shown in FIG. 1 (a) before or after inserting the separator 3 after the positive electrode mixture 2 is loaded in the battery case 1. Thus, the sealant 7 is applied to the inner peripheral surface of the battery case 1 near the opening including the annular support portion 1c. The sealant 7 is generally a mixture of an adhesive and a solvent such as xylene,
It is applied for the purpose of preventing liquid leakage when a dry battery is formed by sealing the space between the sealing body and the battery case 1 in a liquid-tight manner. In addition, the separator 3 is the positive electrode mixture 2 that is stacked.
Is projected to the upper side with respect to the upper end of the. This is to prevent the gelled negative electrode from coming into direct contact with the positive electrode mixture 2 to cause a short circuit, and to prevent the gelled negative electrode from wavy during injection and beyond the separator 3 to enter the positive electrode mixture 2 side. Is.

However, as clearly shown in FIGS. 6 (a) to 6 (c), a portion of the separator 3 inserted into the laminated cylindrical positive electrode mixture 2 that protrudes above the positive electrode mixture 2 largely. The end of winding of the ring is opened by the rigidity of itself so that it can be flipped from the winding position, and the annular support portion 1a
May come into contact with. When such a situation occurs, the sealant 7 applied on the annular support 1c is absorbed by the separator 3 due to the capillary phenomenon. Therefore, the sealing agent 7 becomes thin at the location where the separator 3 is in contact with the annular support portion 1c, and the effect of suppressing the creep phenomenon of the electrolytic solution between the annular support portion 1c and the sealing body at that location is reduced, resulting in a dry battery. At times, this may cause leakage of the electrolytic solution to the outside through the gap between the annular support 1c and the sealing body.

In particular, when a non-woven fabric treated with a surfactant is used as the separator 3 for the purpose of increasing the absorbing speed of the electrolytic solution, the separator 3 is used.
The amount of the sealing agent 7 absorbed by the above increases, and the above problem becomes more remarkable. Further, in a dry battery in which the positive electrode mixture 2 having a small thickness such as a single 6 type dry battery (LR61) is incorporated, the above problem is likely to occur because the gap between the separator 3 and the annular support portion 1c is narrow.

In order to solve the above problem, therefore, the separator 3 may be wound in a state in which an adhesive is applied in advance on the upper end of the winding end so that the upper end of the winding end is adhered so as not to be opened. Conceivable. However, when such means is adopted, not only the amount of adhesive applied and the timing of application need to be adjusted, but also extra equipment costs are required, resulting in high costs. There arises a problem that the adhesive is likely to adhere to the winding roller for winding the piece to form the separator 3.

Moreover, when the upper end of the winding end of the separator 3 is adhered as described above, the following new problems occur. That is, the upper end opening of the cylindrically wound separator 3 is deformed into a state of being folded inward by the pressing of the sealing body by the insulating gasket when the sealing body is fitted in the battery case 1. As a result, the electrolytic solution is sealed in close contact with the gasket. That is, in the alkaline dry battery, the insulating gasket of the sealing body also has a function as a lid plate for sealing the electrolytic solution. Therefore, when the upper end of the winding end of the separator 3 is adhered, the rigidity of the upper open end portion of the separator 3 is increased,
It will not easily deform against the pressure of the insulating gasket,
A new serious problem arises in that the upper opening of the separator 3 does not surely come into close contact with the insulating gasket. Further, such a problem similarly occurs when the upper end of the winding end of the separator 3 is welded by means of, for example, an iron or an ultrasonic wave, instead of the adhesive.

Therefore, the present invention has been made in view of the above-mentioned problems of the prior art, and provides a dry battery capable of surely preventing the liquid leakage due to the reduction of the sealing agent by a simple structure which does not increase the cost. It is intended to be provided.

[0010]

In order to achieve the above-mentioned object, a dry battery according to the present invention has a bottomed cylindrical battery case having a positive electrode convex portion serving as a positive electrode terminal at the center of the bottom surface. A hollow cylindrical positive electrode mixture is accommodated, inside the positive electrode mixture, a gelled negative electrode is accommodated via a cylindrical separator, in which the opening of the battery case is sealed by a sealing body, The separator has a rectangular shape 4.
It is characterized in that a separator piece having a notch formed by cutting at least the corner portion on the side of the sealing body at the winding end of one corner portion is wound into a cylindrical shape.

In this dry battery, since a portion corresponding to the upper end of the winding end, which is separated from the winding portion in the conventional separator in a flipping state, is notched and has no substance, the upper end of the winding end is the battery case. There is no problem such as contact with the annular support portion and absorption of the sealant. Therefore, in this dry battery, troubles such as electrolyte leakage due to the reduction of the sealing effect between the annular support portion and the insulating gasket of the sealing body due to the reduction of the sealing agent do not occur. Further, since this dry battery has a very simple structure in which only the notch is formed in the upper end of the winding end of the separator, the cost does not increase.

In the above invention, in the separator piece, a projecting piece having the same shape as the cutout shape formed in the corner of the winding start end on the side of the sealing body at the end of the winding is integrally projected. It preferably has an established shape.

As a result, an unnecessary loss portion does not occur in the material removal when the hoop material is cut to obtain the separator piece, so that the chip removal processing by the loss portion is not necessary. Moreover, the protruding piece helps prevent the occurrence of a problem such as insufficient stacking when the separator piece is wound,
There is an advantage that the required function as a separator can always be ensured.

In the above invention, the notch may have any of a straight line obliquely cut shape, a rectangular cut shape, an arc shape and an L-shaped shape with curved corners. Thereby, the separator can be formed by selecting a shape that is the most difficult to deform in accordance with the material of the separator piece.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1A is a vertical sectional view showing a dry battery according to an embodiment of the present invention,
(B), (c) is a partially broken perspective view and an enlarged plan view of a state before sealing. In the figure, the battery case 1 is formed in a bottomed cylindrical shape in which a positive electrode convex portion 1a serving as a positive electrode terminal is integrally bulged from the center of the bottom surface. In the battery case 1, as a power generation element, for example, a plurality of positive electrodes (for example, four in this embodiment are illustrated) that are pressure-molded in the shape of a hollow cylinder (ring) containing manganese dioxide as a main component. The mixture 2 and the gelled negative electrode 8 containing zinc alloy powder as a main component are housed in a state of being separated with a separator 9 interposed between the separator pieces and being cylindrically wound.

The outer peripheral surface of each positive electrode mixture 2 is a battery case 1.
Is in contact with the inner peripheral surface of. The bottom opening of the separator 9 is closed by the bottom separator 4 formed of a film that allows only ions to pass therethrough, and the gelled negative electrode 8 is housed in the central space surrounded by the separator 9 and the bottom separator 4. ing. The bottom separator 4 has a function of separating the gelled negative electrode 8 and the battery case 1 serving as a positive electrode so as not to be internally short-circuited.

Further, an electrolytic solution (not shown) made of an alkaline aqueous solution such as KOH or NaOH is injected into the battery case 1. An annular groove 1b is formed on the outer peripheral surface by grooving at a location near the opening of the battery case 1, and the annular supporting portion 1c is formed on the inner surface side by the annular groove 1b.
Is bulged. At a location near the opening of the battery case 1, a sealing body 10 having both functions as a current collector and a negative electrode terminal is arranged in a state of being supported on the annular support portion 1c.

The sealing body 10 is inserted into the gelled negative electrode 8 to collect electrons from the gelled negative electrode 8 and a rod-shaped negative electrode current collector 11 and an insulating gasket 12 for supporting the negative electrode current collector 11 in a central portion thereof. And the insulating gasket 1 while being insulated from the battery case 1 by the insulating gasket 12.
2 and a cap-shaped negative electrode terminal 14 supported on the washer 13 and in contact with the negative electrode current collector 11 in an electrically connected state. The resin-made insulating gasket 12 has a thin, easily breakable portion 12 for breaking and releasing gas when the internal pressure of the battery rises.
a is provided.

When the sealing body 10 is fitted into the battery case 1 through its opening, the upper opening of the cylindrical separator 9 is pressed by the insulating gasket 12 as shown in FIG. When the separator 9 is deformed so as to be bent inward, the deformed portion of the separator 9 comes into close contact with the insulating gasket 12 and seals the electrolytic solution so as not to leak out. The opening edge of the battery case 1 is swaged inwardly in a curl shape after the sealing body 10 is fitted into the battery case 1. As a result, the sealing body 10 is pinched between the opening edge of the battery case 1 and the annular support portion 1c, and the opening of the battery case 1 is liquid-tightly sealed.

As shown in the development view of FIG. 2, the separator 9 is provided with a notch 17 having a shape in which a corner of the winding end of the rectangular separator piece is obliquely cut by a straight line. . This separator 9 is, for example, in the case of an AA type dry battery, is made into a cylindrical shape by winding the above-mentioned separator piece about two turns, and when it is inserted into each positive electrode mixture 2 in this state, As clearly shown in b), since the portion corresponding to the upper end of the winding end separated from the winding portion in the conventional separator 9 in a flipping state becomes the notch 17 and no substance exists, the upper end of the winding end is The problem that the sealing agent is absorbed by coming into contact with the annular support portion 1c of the battery case 1 does not occur.

Therefore, in the above dry battery, there is a problem such as electrolyte leakage due to the reduction of the sealing effect between the annular support 1 and the insulating gasket 12 of the sealing body 10 due to the reduction of the sealing agent. Does not occur. Moreover, this effect is due to the fact that the notch 1 is formed above the winding end of the separator 9.
It can be obtained by an extremely simple configuration in which only 7 is formed, and the cost does not increase. Note that, for example, in the case of a thin dry battery, the separator 9 is formed into a tubular shape by winding the separator piece around three turns, but in this case as well, the same effect as described above can be obtained.

By the way, as a measure for preventing the end of winding of the portion of the separator 9 projecting above the positive electrode mixture 2 from popping open and coming into contact with the annular support portion 1a, in addition to the above embodiment, The stacking height of the positive electrode mixture 2 is set to be substantially the same as the length of the separator 9, and the separator 9
The means for shortening the protruding length from the positive electrode mixture 2 and the means for increasing the thickness of the insulating gasket 12 and shortening the separator 9 by that amount can be considered. However, the former means causes a problem that the gelled negative electrode 8 and the positive electrode mixture 2 are easily short-circuited, and the latter means causes the positive electrode mixture 2 and the gelled negative electrode 8 to be increased in proportion to the thickness of the insulating gasket 12. There is a problem that the storage space is reduced and the increase in capacity is hindered. The dry battery of the above-mentioned embodiment can reliably prevent the separator 9 from coming into contact with the annular support portion 1a by an extremely simple means without causing the problems described above.

The present invention is not limited to the dry battery having the structure shown in FIG. 1, but any dry battery having an inside-out structure can be applied to obtain the same effect as described above. Obtainable.

FIG. 3 shows a separator piece in a developed state of the separator 9 of the modified example. In this separator 9, in addition to forming the notch 17 at the upper end of the winding end of the separator piece, the separator piece is also formed. The protruding piece 18 having the same shape as the shape of the defect due to the notch 17 is also provided above the winding start end of the
Are formed. In general, the separator piece is formed by cutting out the hoop material fed from the separator base material roll. However, in the separator 9, an unnecessary loss portion does not occur during material removal when the hoop material is cut, so that the loss is reduced. It is not necessary to remove chips by parts. Moreover, the protruding piece 18 is useful for preventing the occurrence of a problem such as insufficient stacking when the separator piece is wound, and has an advantage that the required function of the separator 9 can be always ensured. According to the measurement results, it is preferable that the protruding piece 18 has a protruding length of 1.5 mm and a protruding width of about 5 mm in the AA dry battery.

FIG. 4 shows notches 19 to 21 of modified examples, respectively.
It is a partial front view which showed the separator 9 which has.
The notch 19 in (a) is rectangular, the notch 20 in (b) is arcuate, and the notch 21 in (c) is L-shaped with its corners curved. These notches 19 to 21 are selected such that they are the most difficult to deform depending on the material of the separator piece and the like.

5 (a) to 5 (c) are all shown in FIG.
It is a development view showing another modification of. These separators 9 are common in that a notch 17 having a shape obtained by obliquely cutting with a straight line similar to that shown in the embodiment is provided, but the separator 9 in (a) has a winding end of the separator piece. Notches 17 are formed in the upper portions of the end and the winding start end, respectively, so that the separator piece can be wound without orientation of the winding start end and the winding end end.

In the separator 9 of (b), notches 17 are formed at the upper ends of the winding end end and the winding start end of the separator piece, respectively, and also in the lower part of the winding end end. Is formed, and the separator piece can be wound by eliminating the directionality between the winding start end and the winding end end and the vertical directionality at the winding end end. In the separator 9 of (c), the notch 17 is formed in each of the four corners of the rectangular separator piece, and the separator piece can be wound without any directionality.

[0028]

As described above, according to the dry battery of the present invention,
In the conventional separator, since the part corresponding to the winding end corner that was separated from the winding part in the flipping state is notched and there is no substance, the winding end corner of the separator is the annular support part of the battery case. There is no problem such that the sealant comes into contact with the sealant to absorb the sealant. Therefore, in this dry battery, troubles such as electrolyte leakage due to the formation of a gap between the annular support portion and the insulating gasket of the sealing body due to the decrease in the amount of the sealing agent do not occur. Further, since this dry battery has a very simple structure in which only the notch is formed in the upper end of the winding end of the separator, the cost does not increase.

[Brief description of drawings]

FIG. 1A is a longitudinal sectional view showing a dry battery according to an embodiment of the present invention, and FIGS. 1B and 1C are partially broken perspective views and enlarged plan views of a state before sealing.

FIG. 2 is a development view of a separator in the above dry battery.

FIG. 3 is a development view showing a modified separator of the above dry battery.

4A to 4C are partial front views each showing a modified example of the notch of the separator in the above dry battery.

5A to 5C are development views showing other modified examples of the separator in the dry battery of the above.

FIG. 6 shows a conventional dry battery before sealing, (a) is a longitudinal sectional view, (b) is a partially broken perspective view,
(C) is an enlarged plan view.

[Explanation of symbols]

1 battery case 1a Positive electrode protrusion 2 Positive electrode mixture 8 Gel-like negative electrode 9 separator 10 Sealing body 17, 19-21 Notches 18 protruding piece

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shuji Fujiwara             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Tomonori Kawano             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 5H021 AA01 BB04 BB13 CC05 CC17                       HH10                 5H024 AA03 AA14 BB04 BB09 CC02                       CC06 CC08 CC14 CC17 DD02                       DD04 DD05 DD09 HH15

Claims (3)

[Claims] 1. A hollow-cylindrical positive electrode mixture is housed in a battery case formed in a bottomed cylindrical shape having a positive electrode convex portion serving as a positive electrode terminal at the center of the bottom surface, and the inside of the positive electrode mixture is In a dry battery in which a gelled negative electrode is accommodated through a cylindrical separator, and the opening of the battery case is sealed by a sealing body, the separator has at least the winding end of the four rectangular corners. A dry battery, characterized in that it is formed by winding a separator piece having a notch in which a body side corner is cut into a cylindrical shape. 2. The separator is integrally provided with a projecting piece having the same shape as a cutout formed in a corner at the end of winding at the side of the sealing body at the end of winding. The dry battery according to claim 1, which has a shape. 3. The cutout has any one of a straight line obliquely cut shape, a rectangular cut shape, an arc shape and an L-shaped shape with a curved corner portion.
The dry battery described in.