WO2011027502A1

WO2011027502A1 - Alkaline dry battery

Info

Publication number: WO2011027502A1
Application number: PCT/JP2010/004629
Authority: WO
Inventors: 田野英二
Original assignee: パナソニック株式会社
Priority date: 2009-09-02
Filing date: 2010-07-16
Publication date: 2011-03-10
Also published as: JP2012226825A

Abstract

Disclosed is an alkaline dry battery wherein an open end (11) of a battery case (1) is sealed with a negative electrode terminal plate (7) with a resin sealing body (5) interposed therebetween. A shoulder part (12b) of a sealing end (12) of the battery case (1) and a central flat plate part (7a) of the negative electrode terminal plate (7) are formed from the same material, and the thickness of the shoulder part (12b) of the battery case (1) is 0.2-0.4 mm (inclusive). When the thickness of the shoulder part (12b) of the battery case (1) is represented by Tp [mm] and the thickness of the central flat plate part (7a) of the negative electrode terminal plate (7) is represented by Tn [mm], the relation 1.0 ≤ (Tn/Tp) ≤ 2.0 is satisfied.

Description

Alkaline battery

The present invention relates to an alkaline battery, and more particularly to an alkaline battery in which a battery case (functioning as a positive terminal) is sealed with a negative terminal plate.

Alkaline batteries are widely used today as a main power source for daily necessities, toys, hobby supplies, game machines, portable music players and electronic devices. In addition, the packaging forms of alkaline batteries at the time of distribution are diversified.

Furthermore, in recent years, there has been an increasing demand for product safety from customers, and there has been a demand for improved leakage resistance of alkaline batteries. For example, there is a demand for an alkaline battery that does not leak even if the alkaline battery in a packaged state is accidentally dropped during distribution, or dropped from a high place with the alkaline battery loaded in the device used.

Incidentally, the negative electrode terminal plate of an alkaline battery is required to be thin for economic reasons. However, a thin negative electrode terminal plate may not be able to withstand the pressure during sealing. Even if the thin negative electrode terminal plate can withstand the pressure at the time of sealing, the negative electrode terminal plate may be cracked during distribution or use. Therefore, a negative electrode terminal plate that can be thinned without reducing the strength has been proposed (Patent Document 1).

Also, the battery case of an alkaline battery is required to be thin for reasons such as increasing the capacity of the alkaline battery. However, reducing the thickness of the battery case may cause damage to the battery case during distribution or use. Thus, a battery case that can be thinned without reducing the strength has been proposed (Patent Document 2).

Furthermore, it is known that alkaline batteries generate gas when used under predetermined conditions. In order to avoid the generated gas from leaking to the outside, the alkaline battery is sealed (Patent Document 3).

JP 2006-107873 A JP-A-9-306441 JP 2001-509632 A

However, even if the strength of the negative terminal plate is increased, the strength of the battery case is increased, or the shape of the resin sealing body is devised, a plurality of alkaline batteries are dropped in a state of being arranged in series. It was found that the alkaline electrolyte sometimes leaks.

The present invention has been made in view of the above problems, and an object of the present invention is to prevent leakage of an alkaline electrolyte when a plurality of alkaline batteries are dropped in a state of being arranged in series.

The alkaline dry battery according to the present invention includes a battery case (positive electrode terminal), a positive electrode, a separator, a negative electrode, a negative electrode terminal plate, and a resin sealing body. The battery case has a cylindrical shape having a sealed end and an open end, and the sealed end has a protrusion and a shoulder. The protrusion is located in the center of the sealing end, and the shoulder extends radially inward from the side wall of the battery case and is connected to the protrusion. The positive electrode, the separator, and the negative electrode are disposed in this order from the inner wall surface of the battery case toward the radially inner side, and the separator is also disposed between the shoulder and the negative electrode. The negative electrode terminal plate has a central flat plate portion and a peripheral portion, the central flat plate portion covers the opening end of the battery case, and the peripheral portion is an opening edge portion of the battery case through the peripheral annular portion of the resin sealing body. It is fixed to. The resin sealing body has a peripheral annular portion, a central cylindrical portion, a connecting portion, and a thin portion, and the central cylindrical portion is disposed to face the inner surface of the central flat plate portion of the negative electrode terminal plate, and the connecting portion is the center. A cylindrical part and a peripheral annular part are connected, and the thin part is provided in the connection part and is relatively thin.

In such an alkaline battery, the shoulder portion of the battery case and the central flat plate portion of the negative electrode terminal plate are made of the same material, and the thickness of the shoulder portion of the battery case is 0.2 mm or more and 0.4 mm or less. When the thickness of the shoulder portion is Tp [mm] and the thickness of the central flat plate portion of the negative electrode terminal plate is Tn [mm], 1.0 ≦ (Tn / Tp) ≦ 2.0 is satisfied.

When the alkaline batteries having the above configuration are arranged in series and dropped, the depression of the protruding portion of the battery case by the central flat plate portion of the negative electrode terminal plate can be prevented and the depression of the central flat plate portion of the negative electrode terminal plate by the protruding portion of the battery case can be prevented. Can be prevented.

In the alkaline dry battery according to the present invention, the size of the corner located near the sealing end of the battery case among the corners formed by the axial direction of the central cylindrical portion and the thin wall portion is preferably 60 degrees or more and 90 degrees or less. . Thereby, even if it is a case where the center flat plate part of a negative electrode terminal plate is dented, it can prevent that a resin sealing body moves to the sealing end side of a battery case.

In the present invention, it is possible to prevent the alkaline electrolyte from leaking from the alkaline battery even if the alkaline batteries are dropped in a state where they are arranged in series.

FIG. 1 is a table summarizing the results of experiments conducted to investigate the cause of liquid leakage during distribution. FIG. 2 is a plan view showing a state in which a plurality of shrink packs are packed in a cardboard box. FIGS. 3A and 3B are half cross-sectional views of an alkaline dry battery for explaining the first reason that liquid leakage occurs. 4 (a) to 4 (c) are half cross-sectional views of an alkaline dry battery for explaining a second reason that liquid leakage occurs. FIG. 5 is a half sectional view of an alkaline battery according to an embodiment of the present invention. FIG. 6 is an enlarged view of a region VI shown in FIG. FIG. 7 is an enlarged view of the region VII shown in FIG. FIG. 8 is a table summarizing the results of Examples 1-6 and Comparative Examples 1-2. FIG. 9 is a table summarizing the results of Examples 7 to 12 and Comparative Examples 3 to 4.

Before explaining the embodiments of the present invention, the background of the inventor's completion of the present invention will be described.

When distributing alkaline batteries, generally, a plurality of shrink packs (shrink packs are a pack of a plurality of alkaline batteries arranged in parallel) are packed in a cardboard box or the like. Thus, even if it protects and distribute | circulates an alkaline battery, the malfunction that an alkaline battery leaks during distribution | circulation has generate | occur | produced. As the cause, it is considered that the alkaline battery is accidentally dropped during distribution. In order to investigate the cause of the above-mentioned problem, the present inventor dropped a plurality of shrink packs packed in a cardboard box and examined whether or not a liquid leak occurred. Specifically, eight alkaline batteries were arranged in parallel to produce one shrink pack, and the five shrink packs were packed in a cardboard box. Five cardboard boxes were prepared (200 alkaline batteries were used in this experiment). The cardboard box was dropped once from a height of 1.5 m, and the number of batteries in which liquid leakage occurred immediately after dropping, 1 day after dropping, 3 days after dropping, and 1 week after dropping was examined. The obtained results are shown in FIG.

As shown in FIG. 1, liquid leakage occurred in some alkaline batteries. In addition, alkaline batteries with liquid leakage included alkaline batteries with liquid leakage immediately after dropping, and alkaline batteries with liquid leakage after dropping for a while. When the alkaline battery in which the liquid leakage occurred was disassembled, in any of the alkaline batteries, the thin portion of the resin sealing body was broken. However, in alkaline batteries where liquid leakage occurs immediately after dropping, the resin sealant moves closer to the sealing end of the battery case, whereas in alkaline batteries where liquid leakage occurs after a while after dropping, a separator is used. Was torn in the portion located between the negative electrode and the shoulder of the battery case. From these results, the inventor of the present application considered that there are two reasons why liquid leakage occurs when a plurality of shrink packs packed in a cardboard box are dropped. The reason will be described with reference to FIGS.

FIG. 2 is a plan view showing a state where a plurality of shrink packs P, P,... Are packed in a cardboard box B. FIG. 3 (a) to 3 (b) are half sectional views of the alkaline dry battery for explaining the first reason that the liquid leakage occurs. FIGS. 4 (a) to 4 (c) show the liquid leakage. It is a half sectional view of an alkaline dry battery for explaining the 2nd reason to do.

In each shrink pack P, the

alkaline batteries

10, 10,... Are arranged so that the outer surfaces of the

battery cases

1, 1,. However, when attention is paid to the

alkaline batteries

10 and 10 adjacent to each other in the region X shown in FIG. 2, the protrusion of the battery case 1 of one alkaline battery 10 as shown in FIGS. 2, 3A, and 4A. The portion 12a and the central flat plate portion 7a of the negative electrode terminal plate 7 of the other alkaline dry battery 10 are adjacent to each other. Therefore, when the cardboard box B shown in FIG. 2 is dropped, when the central flat plate portion 7a of the negative electrode terminal plate 7 is recessed by the protruding portion 12a of the battery case 1, and when the central flat plate portion 7a of the negative electrode terminal plate 7 protrudes. It is conceivable that the portion 12a is recessed.

When the central flat plate portion 7a of the negative electrode terminal plate 7 is recessed by the protruding portion 12a of the battery case 1, as shown in FIG. 3 (b), the head portion 6a of the negative electrode current collector 6 and the central cylindrical portion 5a of the resin sealing body 5 are used. Is pushed by the negative electrode terminal plate 7 and moves to the sealing end 12 side of the battery case 1. At this time, the peripheral annular portion 5 b of the resin sealing body 5 remains fixed to the opening edge of the battery case 1. Therefore, a breakage occurs in the connecting portion 5c (particularly the thin portion 5d) of the resin sealing body 5, and as a result, the alkaline electrolyte leaks. That is, the first reason for the liquid leakage due to the drop (hereinafter, simply referred to as “first reason”) is the central cylindrical shape of the resin sealing body 5 due to the depression of the central flat plate portion 7a of the negative electrode terminal plate 7. The part 5a moves to the sealing end 12 side of the battery case 1, and as a result, the resin sealing body 5 is torn at the thin part 5d. Therefore, in this case, it is considered that liquid leakage occurs as soon as the cardboard box B shown in FIG. 2 is dropped.

When the protruding portion 12a of the battery case 1 of the alkaline battery is recessed by the central flat plate portion 7a of the negative electrode terminal plate 7, the shoulder portion 12b of the battery case 1 is on the opening end 11 side of the battery case 1 as shown in FIG. Move to. Therefore, the separator 4 is broken at a portion located between the shoulder portion 12 b and the negative electrode 3, and the negative electrode 3 flows through the broken portion of the separator 4 toward the inner surface of the sealing end 12 of the battery case 1. Thereby, since battery case 1 (positive electrode terminal) and negative electrode 3 contact each other, an internal short circuit occurs. When an internal short circuit occurs, the internal pressure of the alkaline battery increases, and as a result, a fracture occurs in the thin portion 5d of the resin sealing body 5 as shown in FIG. In other words, the second reason for the liquid leakage due to the drop (hereinafter simply referred to as “second reason”) is that an internal short circuit occurs because the separator 4 is broken due to the deformation of the protruding portion 12a of the battery case 1. As a result, the resin sealing body 5 is torn at the thin portion 5d. Therefore, in this case, it is considered that liquid leakage occurs after the cardboard box B shown in FIG.

In order to eliminate the first reason, deformation of the central flat plate portion 7a of the negative electrode terminal plate 7 may be prevented, and specifically, the strength of the central flat plate portion 7a of the negative electrode terminal plate 7 may be increased. However, if the strength of the central flat plate portion 7a of the negative electrode terminal plate 7 is increased, the projecting portion 12a of the battery case 1 is easily recessed when the cardboard box B shown in FIG. 2 is dropped. Cause leakage.

In order to eliminate the second reason, the deformation of the shoulder 12b of the battery case 1 may be prevented, and specifically, the strength of the shoulder 12b may be increased. However, when the strength of the shoulder portion 12b of the battery case 1 is increased, the central flat plate portion 7a of the negative electrode terminal plate 7 tends to be recessed when the cardboard box B shown in FIG. 2 is dropped. Cause leakage.

Based on the above experimental results and considerations on the results, the inventor of the present application can suppress the liquid leakage due to the first reason and the liquid leakage due to the second reason at the same time. It is not sufficient to optimize the strength of either the portion 7a or the shoulder portion 12b of the battery case 1, and the strength of both the central flat plate portion 7a of the negative electrode terminal plate 7 and the shoulder portion 12b of the battery case 1 is optimized. It was considered preferable to make it. An embodiment of the present invention will be described below with reference to the drawings. In addition, this invention is not limited to embodiment shown below.

FIG. 5 is a half sectional view of the alkaline dry battery according to the present embodiment. FIG. 6 is an enlarged view of a region VI shown in FIG. FIG. 7 is an enlarged view of the region VII shown in FIG.

Alkaline batteries have a battery case 1 that also serves as a positive electrode terminal. The battery case 1 is press-molded into a predetermined size and a predetermined shape by a known method using, for example, a nickel-plated steel plate, and has a cylindrical shape having an opening end 11 and a sealing end 12. The sealing end 12 includes a projecting portion 12a and a shoulder portion 12b. The protruding portion 12a is located at the center of the sealing end 12 and protrudes outside the battery case 1 from the shoulder portion 12b. The shoulder 12b extends radially inward from the side wall of the battery case 1 and is connected to the protrusion 12a.

The positive electrode 2 is in close contact with the inner wall surface of the battery case 1. The positive electrode 2 has a cylindrical shape, and the negative electrode 3 is provided in the hollow portion of the positive electrode 2 via a separator 4. The separator 4 is provided not only between the positive electrode 2 and the negative electrode 3 but also between the shoulder 12 b of the battery case 1 and the negative electrode 3.

Here, referring to the materials of the positive electrode 2, the separator 4, and the negative electrode 3, the positive electrode 2 includes a positive electrode active material containing manganese dioxide powder and the like, a conductive agent such as graphite, and an alkaline electrolyte such as an aqueous potassium hydroxide solution. Contains. The separator 4 is a nonwoven fabric in which, for example, polyvinyl alcohol fiber and rayon fiber are mixed, and holds an alkaline electrolyte. The negative electrode 3 includes, for example, a negative electrode active material such as zinc powder or zinc alloy powder, a gelling agent such as sodium polyacrylate, and an alkaline electrolyte such as an aqueous potassium hydroxide solution. As the negative electrode active material, it is preferable to use a zinc alloy powder excellent in corrosion resistance. Furthermore, in consideration of the environment, it is preferable to use mercury, cadmium, lead, or a zinc alloy powder free of all of these. Examples of the zinc alloy include a zinc alloy containing indium, aluminum, and bismuth. The alkaline electrolyte may contain 30 to 40% by weight (preferably 32 to 35% by weight) potassium hydroxide and 0.5 to 3% by weight zinc oxide. In addition, what is necessary is just to set suitably content of each material in the positive electrode 2, content of each material in the negative electrode 3, the thickness of the separator 4, etc. FIG.

The open end 11 of the battery case 1 is sealed by a sealing unit 9, and the sealing unit 9 has a resin sealing body 5, a negative electrode current collector 6, and a negative electrode terminal plate 7.

The negative electrode terminal plate 7 is produced by, for example, press-molding a nickel-plated steel plate into a predetermined size and a predetermined shape, and has a central flat plate portion 7a and a peripheral annular portion (peripheral portion) 7b. The central flat plate portion 7 a covers the open end 11 of the battery case 1. The peripheral annular portion 7 b is located on the inner side in the axial direction of the battery case 1 with respect to the central flat plate portion 7 a, and is fixed to the opening edge of the battery case 1 via the peripheral annular portion 5 b of the resin sealing body 5. . Further, a plurality of gas holes (not shown) are formed in the peripheral annular portion 7b, so that the gas in the battery case 1 can be released when the thin portion 5d of the resin sealing body 5 is broken.

The resin sealing body 5 is manufactured by injection molding a resin such as polyamide or polypropylene into a predetermined size and a predetermined shape. The resin sealing body 5 is preferably made of 6,6-nylon, 6,10-nylon or 6,12-nylon. Thereby, the resin sealing body 5 excellent in alkali resistance and heat resistance can be provided.

The resin sealing body 5 has a central cylindrical portion 5a, a connecting portion 5c, and a thin portion 5d in addition to the peripheral annular portion 5b. The central cylindrical portion 5a is opposed to the inner surface of the central flat plate portion 7a of the negative electrode terminal plate 7, and a through hole is formed in the central cylindrical portion 5a so as to extend in the thickness direction. The connecting part 5c connects the central cylindrical part 5a and the peripheral annular part 5b, and has a thin part 5d. The thin part 5d is a relatively thin part in the connecting part 5c.

The negative electrode current collector 6 is produced by pressing a wire such as silver, copper, or brass into a predetermined shape and a predetermined size, and has a nail shape having a head 6a. The surface of the negative electrode current collector 6 is preferably plated with tin or indium. Thereby, it can prevent that an impurity is mixed in the negative electrode current collector at the time of processing of the negative electrode current collector 6, and a concealment effect can be obtained. Such a negative electrode current collector 6 is inserted into the through hole formed in the central cylindrical portion 5 a of the resin sealing body 5, and the head portion 6 a is in contact with the inner surface of the central flat plate portion 7 a of the negative electrode terminal plate 7. The tip located on the opposite side of the head 6 a is present in the negative electrode 3.

Such an alkaline battery satisfies the following (formula 1) and (formula 2). In (Expression 1) and (Expression 2), In is the Vickers hardness Hv of the central flat plate portion 7 a of the negative electrode terminal plate 7, and Ip is the Vickers hardness Hv of the shoulder portion 12 b of the battery case 1.

1.0 ≦ (In / Ip) ≦ 2.0: (Formula 1)
90 ≦ Ip ≦ 140: (Formula 2)
When the Vickers hardness ratio (In / Ip) is small (for example, less than 1.0), the central flat plate portion of the negative electrode terminal plate is likely to be recessed when the alkaline batteries are dropped in a state of being arranged in series. Therefore, liquid leakage is likely to occur for the first reason. On the other hand, when the Vickers hardness ratio (In / Ip) is large (eg, exceeding 2.0), the shoulder of the battery case is easily deformed when the alkaline batteries are dropped in a state where they are arranged in series. Therefore, liquid leakage is likely to occur due to the second reason. However, in the alkaline battery according to this embodiment, the Vickers hardness ratio (In / Ip) satisfies (Equation 1). Therefore, even if the alkaline batteries according to this embodiment are accidentally dropped in a state where they are arranged in series, the negative flat plate 7a can be prevented from being depressed by the shoulder 12b of the battery case 1 and the central flat plate portion 7a of the negative flat plate 7 can be prevented. Since the deformation of the shoulder portion 12b of the battery case 1 by the central flat plate portion 7a can be prevented, the electrolyte solution can be prevented from leaking from the alkaline dry battery according to the present embodiment. In addition, as a situation where the alkaline batteries according to this embodiment fall in a state where they are arranged in series, the alkaline batteries according to this embodiment are accidentally dropped while being packed in a cardboard box B as shown in FIG. For example, the alkaline dry battery according to the present embodiment may be accidentally dropped in a state in which the used device (toy, game device, electronic device, or the like) is filled.

The Vickers hardness ratio (In / Ip) is 1.0 or more and 2.0 or less as shown in (Formula 1), but preferably 1.0 or more and 1.7 or less, and 1.2 or more and 1.4. The following is more preferable. Such Vickers hardness ratio (In / Ip) is measured according to JIS Z 2244 (Vickers hardness test method).

Focusing on the fact that the central flat plate portion 7a of the negative electrode terminal plate 7 and the shoulder portion 12b of the battery case 1 are made of the same material, the Vickers hardness ratio can be rewritten by the thickness ratio. That is, the alkaline battery according to this embodiment only needs to satisfy the following (formula 3) to (formula 5). In (Expression 3) to (Expression 5), Tn is the thickness (mm) of the central flat plate portion 7a of the negative electrode terminal plate 7, and Tp is the thickness (mm) of the shoulder portion 12b of the battery case 1.

1.0 ≦ (Tn / Tp) ≦ 2.0: (Formula 3)
0.2 ≦ Tp ≦ 0.4: (Formula 4)
0.2 ≦ Tn ≦ 0.5: (Formula 5)
When referring to the thickness of the negative electrode terminal plate 7 and the thickness of the battery case 1, if the thickness of the negative electrode terminal plate 7 and the thickness of the battery case 1 are thin, the capacity of the alkaline dry battery can be increased. However, if the thickness of the negative electrode terminal plate 7 and the thickness of the battery case 1 are too thin, it is difficult to ensure the strength of the negative electrode terminal plate 7 and the strength of the battery case 1. Therefore, the thickness of the shoulder portion 12b of the battery case 1 only needs to satisfy (Equation 4), is preferably 0.2 mm or more and 0.3 mm or less, and more preferably about 0.2 mm. The thickness of the central flat plate portion 7a of the negative electrode terminal plate 7 only needs to satisfy (Equation 5), is preferably 0.2 mm or more and 0.4 mm or less, and more preferably about 0.2 mm.

Further, in the resin sealing body 5 in the present embodiment, the angle of the thin portion 5d with respect to the axial direction of the central cylindrical portion 5a and the angle located on the sealing end 12 side of the battery case 1 (hereinafter simply “ The inclination angle θ of the thin portion 5d ”) may be 60 degrees or more and 90 degrees or less. Thereby, even if the central flat plate portion 7a of the negative electrode terminal plate 7 is recessed because the alkaline batteries according to the present embodiment are accidentally dropped in a state where they are arranged in series, the amount of change in the inclination angle θ of the thin portion 5d Can be minimized. Therefore, since the breakage in the thin portion 5d is suppressed, leakage of the electrolytic solution can be suppressed.

If the inclination angle θ of the thin portion is outside the above range, the amount of change in the inclination angle θ of the thin portion increases when the central flat plate portion of the negative electrode terminal plate is recessed. Therefore, since a large stress is applied to the thin portion, the thin portion is easily broken. In addition, if the inclination angle θ of the thin-walled portion is less than 60 degrees, the volume of the sealing unit is increased, so that it is difficult to increase the capacity of the alkaline battery. In addition, if the inclination angle θ of the thin wall portion exceeds 90 degrees, the thin wall portion may not be broken even if the internal pressure of the alkaline battery increases when the alkaline battery is misused. It is difficult to ensure sex. As described above, the inclination angle θ of the thin portion 5d is preferably 60 degrees or more and 90 degrees or less.

As described above, in the present embodiment, leakage of the alkaline electrolyte can be suppressed even when the alkaline batteries are accidentally dropped in a state where they are arranged in series.

Needless to say, the present embodiment is not limited to the case where the battery case is dropped with the protruding portion of the battery case positioned below the negative electrode terminal plate as shown in FIG. For example, even when the negative electrode terminal plate falls in a state where it is located below the protrusion of the battery case, the effect of this embodiment can be obtained.

Hereinafter, embodiments of the present invention will be described in detail. The present invention is not limited to the following examples.

Example 1
The alkaline dry battery of Example 1 was produced according to the method shown below.

1. Manufacturing method of alkaline battery (1) Preparation of positive electrode mixture First, manganese dioxide powder and graphite were mixed at a weight ratio of 94: 6. Next, this mixture was mixed with a 33% by weight potassium hydroxide aqueous solution (alkaline electrolyte) at a weight ratio of 100: 1, and after sufficient stirring, it was compression molded into flakes. Subsequently, the flaky positive electrode mixture was pulverized into granules, and the granular positive electrode mixture was classified using a sieve. A granular positive electrode mixture of 10 to 100 mesh was pressure-molded into a hollow cylinder to obtain a pellet-shaped positive electrode mixture.

(2) Preparation of gelled negative electrode Sodium polyacrylate (gelator), 33 wt% potassium hydroxide aqueous solution (alkaline electrolyte) and zinc powder (negative electrode active material) in a weight ratio of 1:33:66. By mixing, a gelled negative electrode was obtained.

(3) Production of Cylindrical Alkaline Battery An AA alkaline battery shown in FIG. 5 was produced according to the following procedure.

Two pellet-shaped positive electrode mixtures obtained as described above were inserted into the battery case 1, and the pellet-shaped positive electrode mixture was remolded with a pressure jig and adhered to the inner wall surface of the battery case 1. Thereby, the cylindrical positive electrode 2 was formed on the inner wall surface of the battery case 1. After placing the bottomed cylindrical separator 4 in the hollow of the positive electrode 2, a predetermined amount of 33 wt% potassium hydroxide aqueous solution (alkaline electrolyte) was injected into the separator 4. After a lapse of a predetermined time, the gelled negative electrode obtained above was filled inside the battery case in the radial direction from the separator 4. In addition, as the separator 4, the nonwoven fabric which mixed and mixed mainly the polyvinyl alcohol fiber and the rayon fiber was used.

A groove was formed in the vicinity of the open end of the battery case 1 to form a recess. The sealing unit 9 was installed at the opening end 11 of the battery case 1 so as to receive the peripheral annular portion 5b of the resin sealing body 5 of the sealing unit 9 on the concave portion. Specifically, the head 6 a of the nail-like negative electrode current collector 6 is welded to the inner surface of the central flat plate part 7 a of the negative electrode terminal plate 7, and the negative electrode current collector 6 is penetrated through the central cylindrical part 5 a of the resin sealing body 5. It inserted in the hole and inserted in the negative electrode 3. The opening edge of the battery case 1 is bent and the peripheral annular portion 7b of the negative electrode terminal plate 7 is fixed to the opening edge of the battery case 1 via the peripheral annular portion 5b of the resin sealing body 5. Was sealed. Thereafter, the outer label 8 was coated on the outer surface of the battery case 1.

Here, the thickness of the central flat plate portion 7a of the negative electrode terminal plate 7 is 0.4 mm, the thickness of the shoulder portion 12b of the battery case 1 is 0.2 mm, and the inclination angle θ of the thin portion 5d is 80 degrees. . In this manner, 90 alkaline dry batteries according to Example 1 were produced.

2. Test The presence or absence of liquid leakage was investigated using 90 alkaline dry batteries produced.

First, three of the 90 alkaline dry batteries produced were placed in a resin tube, and the resin tube was thermally contracted. This produced 30 test bodies in which three alkaline batteries were arranged in series.

Next, 30 specimens were naturally dropped 10 times continuously from a height of 1.5 m. Thereafter, 30 test specimens were allowed to stand in a room temperature and normal humidity environment, and the specimens were observed immediately after dropping, 1 day after dropping, 3 days after dropping, and 1 week after dropping to check for the presence of liquid leakage. For the test specimen in which the occurrence of liquid leakage was confirmed, the alkaline battery constituting the test specimen was disassembled to investigate the cause of the liquid leakage. That is, the number of batteries that leaked due to the first reason and the number of batteries that leaked due to the second reason were counted. The result is shown in FIG. Note that “only the fracture of the thin portion” shown in FIG. 8 indicates that leakage occurred for the first reason, and “the outflow of the gelled negative electrode” shown in FIG. 8 indicates the second reason. Indicates that a leak occurred.

(Examples 2-6 and Comparative Examples 1-2)
In Examples 2 to 6 and Comparative Examples 1 and 2, the alkaline dry battery was manufactured in the same manner as in Example 1 except for the thickness of the shoulder 12b of the battery case 1 and the inclination angle θ (see FIG. 8) of the thin part 5d. The same test as in Example 1 was conducted to check for the presence of liquid leakage. The results are shown in FIG.

(Examples 7 to 12 and Comparative Examples 3 to 4)
In Examples 7 to 12 and Comparative Examples 3 to 4, except for the thickness of the central flat portion 7a of the negative electrode terminal plate 7, the thickness of the shoulder portion 12b of the battery case 1, and the inclination angle θ of the thin portion 5d (see FIG. 9). Prepared an alkaline dry battery according to the same method as in Example 1, and conducted the same test as in Example 1 to examine the presence or absence of leakage. The results are shown in FIG. Note that “only the fracture of the thin portion” and “the outflow of the gelled negative electrode” described in FIG. 9 are as described above.

(Discussion)
In the battery of Comparative Example 1, the resin sealing body was moved closer to the sealing end, and only the breakage of the thin portion of the resin sealing body was observed. In the battery of Comparative Example 2, the deformation of the shoulder of the battery case, the breakage of the separator, and the outflow of the gelled negative electrode were observed as well as the thin portion of the resin sealant. On the other hand, in the batteries of Examples 1 to 6, no breakage of the thin portion of the resin sealing body and outflow of the gelled negative electrode were observed, and the liquid leakage resistance was excellent.

The same was true for the batteries of Examples 7 to 12 and Comparative Examples 3 to 4. The batteries of Examples 7 to 12 are thinner than the batteries of Examples 1 to 6, but the thickness of the negative terminal plate and the shoulder of the battery case is thinner. Occurrence could be suppressed. As a result, it was found that the batteries of Examples 7 to 12 can realize a high capacity without causing liquid leakage.

Since the occurrence of liquid leakage can be prevented even if the alkaline dry batteries according to the present invention are dropped in a state where they are arranged in series, the alkaline dry battery according to the present invention can be used in any device that uses an alkaline dry battery as a power source.

1 Battery case
1a recess
2 Positive electrode
3 Negative electrode (gelled negative electrode)
4 Separator
5 Resin seal
5a Center tube
5b Peripheral ring
5c Connecting part
5d thin part
6 Negative current collector
6a head
7 Negative terminal plate
7a Center plate
7b Peripheral ring
8 Exterior label
9 Sealing unit
10 Alkaline batteries
11 Open end
12 Sealed end
12a Protrusion
12b shoulder

Claims

A battery case that has a sealed end and an open end and functions as a positive electrode terminal; a positive electrode, a separator, and a negative electrode that are arranged in order from the inner wall surface of the battery case toward the radially inner side; and a resin sealant An alkaline battery including a negative electrode terminal plate for sealing the opening end through
The sealing end has a projecting portion located in the center, and a shoulder portion extending radially inward from the side wall of the battery case and connected to the projecting portion,
The separator is also disposed between the shoulder and the negative electrode,
The negative electrode terminal plate includes a central flat plate portion that covers the open end of the battery case, and a peripheral portion fixed to the open end edge of the battery case via a peripheral annular portion of the resin sealing body. ,
The said resin sealing body connects the said peripheral annular part, the central cylindrical part arrange | positioned facing the inner surface of the said central flat plate part of the said negative electrode terminal plate, the said central cylindrical part, and the said peripheral annular part. A connecting portion and a relatively thin-walled portion provided in the connecting portion;
The shoulder portion of the battery case and the central flat plate portion of the negative electrode terminal plate are made of the same material,
The thickness of the shoulder of the battery case is 0.2 mm or more and 0.4 mm or less,
When the thickness of the shoulder portion of the battery case is Tp [mm] and the thickness of the central flat plate portion of the negative electrode terminal plate is Tn [mm], 1.0 ≦ (Tn / Tp) ≦ 2.0 is satisfied. Alkaline battery.
The alkaline dry battery according to claim 1,
Among the angles formed by the axial direction of the central cylindrical portion and the thin-walled portion, the size of the corner located near the sealing end of the battery case is 60 degrees or more and 90 degrees or less.