Alkaline battery

Abstract

To obtain an alkaline battery capable of preventing an internal short circuit caused by rupture of a separator.SOLUTION: An alkaline battery 1 includes: a bottomed cylindrical positive electrode can 11; a plurality of cylindrical positive electrode mixtures 21 provided inside the positive electrode can 11 and aligned coaxially with the positive electrode can 11 and spaced apart from each other; a separator 22 provided on an inner periphery of the plurality of positive electrode mixtures 21; a negative electrode mixture 23 filled on the inner periphery of the separator 22, a negative electrode current collector (negative electrode current collector 31) inserted into the negative electrode mixture 23; a negative electrode terminal plate 32 provided at an opening of the positive electrode can 11; and an alkaline electrolyte. Therein an R-chamfered first R surface 81 is formed on a corner portion where a first opposing surface 61 of the outer periphery of the positive electrode mixture 21 that faces an adjacent positive electrode mixture 21 is connected to an inner periphery surface 71 of the positive electrode mixture 21.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE The present invention relates to alkaline batteries. [Background technology]

[0002] There is known an alkaline battery in which a plurality of cylindrically shaped positive electrode mixtures are arranged coaxially inside a cylindrically shaped positive electrode can. In the alkaline battery, an electrolyte is filled inside the positive electrode can. In the alkaline battery, the heavy load discharge performance can be improved by increasing the amount of electrolyte absorbed by the positive electrode mixture. There is an alkaline battery in which the amount of electrolyte absorbed by the positive electrode mixture is increased by providing a gap between the aligned positive electrode mixtures, thereby increasing the contact area between the positive electrode mixture and the electrolyte. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-137977 A Summary of the Invention [Problem to be solved by the invention]

[0004] In an alkaline battery, a separator is provided along the inner peripheral surface of a cylindrical positive electrode mixture. In an alkaline battery with a gap in the positive electrode mixture, the separator is broken at a corner where the inner peripheral surface of the positive electrode mixture is connected to the opposing surface of the outer peripheral surface of the positive electrode mixture where the positive electrode mixtures face each other, and this corner may cause an internal short circuit.

[0005] The disclosed technology has been made in view of the above-mentioned points, and has an object to obtain an alkaline battery that can prevent the separator from breaking and causing an internal short circuit. [Means for solving the problem]

[0006] An alkaline battery according to one embodiment of the present disclosure comprises a cylindrical positive electrode can with a bottom, a plurality of cylindrical positive electrode mixtures provided inside the positive electrode can and arranged coaxially with the positive electrode can with gaps between them, a separator provided on the inner periphery of the plurality of positive electrode mixtures, a negative electrode mixture filled on the inner periphery of the separator, a negative electrode current collector inserted into the negative electrode mixture, a negative electrode terminal plate provided at an opening of the positive electrode can, and an alkaline electrolyte, and a first R surface is formed by chamfering the corner where the inner periphery of the positive electrode mixture is connected to a first opposing surface of the outer periphery of the positive electrode mixture that faces an adjacent positive electrode mixture. Effect of the Invention

[0007] According to one aspect of the alkaline battery disclosed in the present application, an alkaline battery can be obtained that can prevent the separator from breaking and causing an internal short circuit. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view of an alkaline battery according to a first embodiment. [Diagram 2] FIG. 2 is a partially enlarged cross-sectional view of a portion A shown in FIG. 1, showing an example of a first R surface. [Diagram 3] FIG. 3 is a partially enlarged cross-sectional view of the portion A shown in FIG. 1, showing another example of the first R surface. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the alkaline battery disclosed in the present application will be described in detail with reference to the drawings. Note that the alkaline battery disclosed in the present application is not limited to the following embodiments.

[0010] (Embodiment 1) <Alkaline battery composition> 1 is a cross-sectional view of an alkaline battery according to embodiment 1. The alkaline battery 1 includes a cylindrical metal positive electrode can 11 with a bottom, a plurality of positive electrode mixtures 21 inserted into the positive electrode can 11, a cylindrical separator 22 with a bottom provided on the inner periphery of the positive electrode mixture 21, a negative electrode mixture 23 filled on the inner periphery of the separator 22, a negative electrode terminal plate 32 provided at the opening of the positive electrode can 11, a resin sealing gasket 35 sandwiched between the edge of the opening of the positive electrode can 11 and the negative electrode terminal plate 32, and a rod-shaped negative electrode current collector (negative electrode current collector) 31 made of a material such as brass and fixed to the inside of the negative electrode terminal plate 32 by spot welding or the like.

[0011] The positive electrode can 11 has a protruding positive electrode terminal 12 formed integrally with its bottom 13 .

[0012] The multiple positive electrode mixtures 21 are each cylindrical in shape and are arranged coaxially with the positive electrode can 11. The multiple positive electrode mixtures 21 are configured to include a first positive electrode mixture 21a, a second positive electrode mixture 21b, and a third positive electrode mixture 21c. The second positive electrode mixture 21b is the positive electrode mixture 21 provided closest to the negative electrode terminal plate 32 among the multiple positive electrode mixtures 21. The third positive electrode mixture 21c is the positive electrode mixture 21 provided closest to the positive electrode terminal 12 among the multiple positive electrode mixtures 21. The first positive electrode mixture 21a is the positive electrode mixture 21 sandwiched between the other positive electrode mixtures 21.

[0013] The multiple positive electrode mixtures 21 contain electrolytic manganese dioxide (EMD) as a positive electrode active material, graphite as a conductive material, polyacrylic acid as a binder, an electrolyte solution mainly containing potassium hydroxide (KOH), and a surfactant (e.g., an anionic surfactant). Inside the positive electrode can 11, gaps are provided between the multiple positive electrode mixtures 21. Providing the gaps between the multiple positive electrode mixtures 21 increases the contact area between the positive electrode mixtures 21 and the electrolyte solution, thereby increasing the amount of electrolyte solution absorbed by the positive electrode mixtures 21. Increasing the amount of electrolyte solution absorbed by the positive electrode mixtures 21 improves the heavy load discharge performance of the alkaline battery 1.

[0014] In the first positive electrode mixture 21a, the second positive electrode mixture 21b, and the third positive electrode mixture 21c, a first opposing surface 61 that faces an adjacent positive electrode mixture 21 among the outer peripheral surfaces of each positive electrode mixture 21 is formed at a corner where the first opposing surface 61 and the inner peripheral surface 71 of each positive electrode mixture 21 are connected to each other, and a first R surface 81 that is R-chamfered is formed.

[0015] Fig. 2 is a partially enlarged cross-sectional view of part A shown in Fig. 1, illustrating an example of a first R surface. In the example shown in Fig. 2, the first opposing surface 61 and the inner circumferential surface 71 are smoothly connected by the first R surface 81.

[0016] Fig. 3 is a partially enlarged cross-sectional view of part A shown in Fig. 1, showing another example of the first R-surface. In the example shown in Fig. 3, a C-chamfered notch surface 84 is formed at the corner where the first opposing surface 61 and the inner circumferential surface 71 are connected. A first R-surface 81 is formed at the portion where the notch surface 84 and the inner circumferential surface 71 are connected.

[0017] 2 and 3 is formed at a corner portion where the first opposing surface 61 and the inner circumferential surface 71 are connected. In FIG. 1, the location other than portion A where the first rounded surface 81 is formed is indicated by an arrow D.

[0018] A second R surface 82 may be formed in a similar shape to the first R surface 81 illustrated in FIGS. 2 and 3 at a corner portion of the outer peripheral surface of the second positive electrode mixture 21b where the second opposing surface 62 facing the negative electrode terminal plate 32 and the inner peripheral surface 71 are connected, specifically, at portion B in FIG. 1 .

[0019] A third R surface 83 may be formed in a similar shape to the first R surface 81 illustrated in FIGS. 2 and 3 at a corner portion where a third opposing surface 63 that faces the bottom 13 of the positive electrode can 11 and the inner circumferential surface 71 are connected to the third positive electrode mixture 21c, specifically, at portion C in FIG. 1 .

[0020] The negative electrode mixture 23 is a gel of zinc alloy powder as a negative electrode active material. The zinc alloy powder is produced by gas atomization or centrifugal atomization. It contains alloy components (bismuth, aluminum, indium, etc.) added to suppress corrosion (to prevent leakage), etc., and potassium hydroxide as an electrolyte.

[0021] The negative electrode current collector 31 is inserted into the center of the negative electrode mixture 23 .

[0022] <Effects> In the alkaline battery 1, the positive electrode mixture 21 and the negative electrode mixture 23 are separated by a separator 22 provided on the inner periphery side of the positive electrode mixture 21. In the alkaline battery 1 configured in this way, if the separator 22 is broken, an internal short circuit occurs.

[0023] When there are no gaps between the multiple positive electrode mixtures 21, the inner circumferential surfaces 71 form a continuous surface and do not abut against the separator 22 with the shape of the corners intact. Therefore, the separator 22 is less likely to be damaged by the positive electrode mixture 21. On the other hand, when there are gaps between the multiple positive electrode mixtures 21 as in the alkaline battery 1 according to the first embodiment, the inner circumferential corners of the positive electrode mixture 21 abut against the separator 22 with the shape of the corners intact at the gaps. Therefore, there is a risk that the corners will break the separator 22 due to the impact of accidentally dropping the alkaline battery 1, causing an internal short circuit.

[0024] Here, in the alkaline battery 1 according to the first embodiment, a first R surface 81 is formed by chamfering a corner at which a first opposing surface 61, which is an outer circumferential surface of the positive electrode mixture 21 and faces an adjacent positive electrode mixture 21, is connected to an inner circumferential surface 71 of the positive electrode mixture 21. Compared to a case where the corner has its original shape, by forming the first R surface 81, the positive electrode mixture 21 is less likely to damage the separator 22, and the separator 22 is also less likely to break.

[0025] In recent years, there has been a trend for the separator 22 to be made thinner in order to improve discharge performance. The thinner the separator 22, the more likely it is to break. However, in the alkaline battery 1 according to the first embodiment, the first rounded surface 81 is formed at the corner of the positive electrode mixture 21 with which the separator 22 is in contact, making the separator 22 less likely to break. This allows the separator 22 to be made thinner, which can contribute to improving the discharge performance of the alkaline battery 1.

[0026] In addition, as in the example shown in FIG. 3, when a C-chamfered cutout surface 84 is formed at a corner and a first R surface 81 is provided at the portion where the cutout surface 84 and the inner circumferential surface 71 are connected, the R becomes small and chipping becomes more likely to occur, but the angle between the cutout surface 84 and the inner circumferential surface 71 becomes an obtuse angle, so that the positive electrode mixture 21 is even less likely to damage the separator 22.

[0027] Furthermore, if a second R surface 82 is formed by chamfering a corner portion where a second opposing surface 62, which faces the negative electrode terminal plate 32, of the outer peripheral surface of the second positive electrode mixture 21b connects to the inner peripheral surface 71, this corner portion becomes less likely to damage the separator 22, and the separator 22 becomes even less likely to tear.

[0028] Furthermore, if a third opposing surface 63, which is part of the outer peripheral surface of the third positive electrode mixture 21c and faces the bottom 13 of the positive electrode can 11, is formed at a corner where the inner peripheral surface 71 is connected to the third opposing surface 63, which faces the bottom 13 of the positive electrode can 11, then this corner will be less likely to damage the separator 22, and the separator 22 will be even less likely to tear.

[0029] Furthermore, if the first positive electrode mixture 21a has the first R surface 81, the second positive electrode mixture 21b has the first R surface 81 and the second R surface 82, and the third positive electrode mixture 21c has the first R surface 81 and the third R surface 83, it becomes possible to form all of the multiple positive electrode mixtures 21 included in the alkaline battery 1 in the same shape. This simplifies the process of manufacturing the positive electrode mixture 21 and reduces the number of types of parts that make up the alkaline battery 1, thereby reducing manufacturing costs and improving yields. [Explanation of symbols]

[0030] 1 alkaline battery 11 Positive electrode can 12 Positive terminal 13 Bottom 21 Positive electrode mixture 21a First positive electrode mixture 21b Second positive electrode mixture 21c Third positive electrode mixture 22 Separator 23 Negative electrode mixture 31 Negative electrode current collector 32 Negative terminal plate 35 Sealing gasket 61 First opposing surface 62 Second opposing surface 63 Third opposing surface 71 Inner peripheral surface 81 1st R surface 82 Second R surface 83 Third R surface 84 Notched surface

Claims

1. A cylindrical positive electrode can with a bottom; A plurality of cylindrical positive electrode mixtures are provided inside the positive electrode can, and are arranged coaxially with the positive electrode can and spaced apart from one another; A separator provided on an inner circumferential side of the plurality of positive electrode mixtures; A negative electrode mixture filled on the inner circumferential side of the separator; a negative electrode current collector inserted into the negative electrode mixture; a negative electrode terminal plate provided at an opening of the positive electrode can; and an alkaline electrolyte; An alkaline battery in which a first opposing surface of the outer peripheral surface of the positive electrode mixture that faces an adjacent positive electrode mixture is connected to an inner peripheral surface of the positive electrode mixture, and a first R surface that is R-chamfered is formed at the corner.

2. 2 . The alkaline battery according to claim 1 , wherein the first opposing surface and an inner circumferential surface of the positive electrode mixture are smoothly connected to each other by the first rounded surface.

3. The corner portion has a C-chamfered cutout surface formed thereon, The alkaline battery according to claim 1 , wherein the first rounded surface is formed at a portion where the cutout surface and the inner circumferential surface are connected.

4. The alkaline battery according to claim 1, wherein a second opposing surface of the outer peripheral surface of the positive electrode mixture that faces the negative electrode terminal plate and a corner portion where the inner peripheral surface of the positive electrode mixture are connected are chamfered to form a second R surface.

5. The alkaline battery according to claim 1, wherein a third opposing surface of the outer peripheral surface of the positive electrode mixture that faces the bottom of the positive electrode can is formed as a third R surface by chamfering at a corner where the inner peripheral surface of the positive electrode mixture is connected to the third opposing surface.

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