Alkaline battery

Abstract

To provide an alkaline battery in which a negative electrode mixture is less likely to leak.SOLUTION: An alkaline battery 1 includes: a bottomed cylindrical positive electrode can 2 having a bottom face on which a positive electrode terminal is formed; a cylindrical positive electrode mixture 3 provided inside the positive electrode can 2; a cylindrical separator 7 provided on the inner peripheral side of the positive electrode mixture 3; a negative electrode mixture 5 filling the inner peripheral side of the separator 7; a current collector rod 6; a gasket 14 having a support part 41 and an annular outer peripheral part 42 and closing an opening 18 of the positive electrode can 2; a negative electrode terminal plate 12 provided opposite the separator 7 with the gasket 14 sandwiched therebetween; a first facing part 421 facing the inner peripheral surface 7a of the separator 7 at an end on the negative electrode terminal plate 12 side; and a second facing part 422 facing the outer peripheral surface 7b of the separator 7 at an end on the negative electrode terminal plate 12 side. A buffer part 43 is formed on the outer peripheral part 42, and the first facing part 421 and the second facing part 422 are provided at positions avoiding the buffer part 43 as viewed along the central axis C of the positive electrode can 2.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] FIELD OF THE INVENTION The present invention relates to alkaline batteries. [Background technology]

[0002] An alkaline battery includes a cylindrical cathode can with a bottom. Inside the cathode can, a cylindrical separator is provided that is coaxial with the cathode can. Inside the cathode can, a cathode mixture is provided on the outside of the separator, and a gelled anode mixture is provided on the inside of the separator. The alkaline battery includes a gasket that closes the opening of the cathode can.

[0003] In alkaline batteries, if the negative electrode material mixture leaks outside the separator, it will cause a short circuit. Therefore, the edge of the separator is abutted against a gasket to prevent the negative electrode material mixture from leaking outside the separator from between the separator and the gasket (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-158457 Summary of the Invention [Problem to be solved by the invention]

[0005] However, for example, when an alkaline battery is dropped with the gasket side facing downwards and hits the floor, the negative electrode mixture that has flowed toward the gasket may leak out from between the separator and the gasket to the outside of the separator.

[0006] The disclosed technology aims to provide an alkaline battery that is less susceptible to leakage of the negative electrode mixture. [Means for solving the problem]

[0007] an annular outer peripheral portion provided on the outer periphery of the support portion; a gasket that closes the opening of the positive electrode can; a negative electrode terminal plate provided on the opposite side of the separator with the gasket in between; a first opposing portion that faces the inner peripheral surface of the separator at the end of the separator that faces the negative electrode terminal plate; and a second opposing portion that faces the outer peripheral surface of the separator at the end of the separator that faces the negative electrode terminal plate. A buffer portion is formed on the outer periphery to relieve the compressive force applied in the radial direction, and the first opposing portion and the second opposing portion are located at positions that avoid the buffer portion when viewed along the central axis of the positive electrode can. [Effects of the Invention]

[0008] According to one aspect of the alkaline battery disclosed in the present application, an alkaline battery in which the negative electrode mixture is less likely to leak can be provided. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view of an alkaline battery according to a first embodiment. [Figure 2] FIG. 2 is a partially enlarged cross-sectional view of a portion A shown in FIG. [Figure 3] FIG. 3 is a cross-sectional view of an alkaline battery according to a first modification of the first embodiment, and is a partially enlarged cross-sectional view of a portion corresponding to portion A shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view of an alkaline battery according to a second embodiment, and is a partially enlarged cross-sectional view of a portion corresponding to portion A shown in FIG. [Figure 5] FIG. 5 is a cross-sectional view of an alkaline battery according to a first modification of the second embodiment, and is a partially enlarged cross-sectional view of a portion corresponding to portion A shown in FIG. [Figure 6]FIG. 6 is a cross-sectional view of an alkaline battery according to a second modification of the second embodiment, and is a partially enlarged cross-sectional view of a portion corresponding to portion A shown in FIG. [Figure 7] FIG. 7 is a cross-sectional view of an alkaline battery according to a third modification of the second embodiment, and is a partially enlarged cross-sectional view of a portion corresponding to portion A shown in FIG. [Figure 8] FIG. 8 is a cross-sectional view of an alkaline battery according to a fourth modification of the second embodiment, and is a partially enlarged cross-sectional view of a portion corresponding to portion A shown in FIG. [Figure 9] FIG. 9 is a cross-sectional view of an alkaline battery according to a fifth modification of the second embodiment, and is a partially enlarged cross-sectional view of a portion corresponding to portion A shown in FIG. [Figure 10] FIG. 10 is a cross-sectional view of an alkaline battery according to a sixth modification of the second embodiment, and is a partially enlarged cross-sectional view of a portion corresponding to portion A shown in FIG. [Figure 11] FIG. 11 is a cross-sectional view of an alkaline battery according to the third embodiment, and is a partially enlarged cross-sectional view of a portion corresponding to portion A shown in FIG. [Figure 12] FIG. 12 is a cross-sectional view of the alkaline battery according to Comparative Example 1, and is a partially enlarged cross-sectional view of a portion corresponding to portion A shown in FIG. [Figure 13] FIG. 13 is a cross-sectional view of an alkaline battery according to Comparative Example 2, and is a partially enlarged cross-sectional view of a portion corresponding to portion A shown in FIG. [Figure 14] FIG. 14 is a diagram showing the results of the evaluation test. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the alkaline battery disclosed in the present application will be described in detail with reference to the drawings. However, the alkaline battery disclosed in the present application is not limited to the following embodiments.

[0011] First Embodiment 1 is a cross-sectional view of an alkaline battery of Embodiment 1. The alkaline battery 1 of Embodiment 1 includes a positive electrode can 2, a positive electrode mixture 3, a negative electrode mixture 5, a current collector 6, a separator 7, a gasket 14, and a negative electrode terminal plate 12.

[0012] The positive electrode can 2 is made of a conductor such as a metal. The positive electrode can 2 is formed in a cylindrical shape with a bottom, and includes a tubular portion 15 and a bottom surface 16. The tubular portion 15 is also formed in a cylindrical shape. The bottom surface 16 is formed integrally with the tubular portion 15 so as to close one end side of the tubular portion 15. A positive electrode terminal 17 is formed in the center of the bottom surface 16. The positive electrode terminal 17 is formed so as to protrude from the inside to the outside of the positive electrode can 2. The other end side of the positive electrode can 2 forms an opening 18. The cross-sectional view shown in FIG. 1 can also be considered as a cross-sectional view cut along a plane including the central axis C of the positive electrode can 2.

[0013] The positive electrode mixture 3 contains manganese dioxide (MnO2), graphite (C), an aqueous potassium hydroxide solution, and a binder. The binder contains, for example, a polymer compound, and forms a solid by bonding powders of manganese dioxide (MnO2) and graphite (C). The positive electrode mixture 3 is formed in a cylindrical shape. The positive electrode mixture 3 is disposed inside the positive electrode can 2 so that its outer surface faces the inner circumferential surface of the cylindrical portion 15 of the positive electrode can 2. The positive electrode mixture 3 is in close contact with the positive electrode can 2 so that the manganese dioxide (MnO2) and graphite (C) are electrically connected to the positive electrode can 2.

[0014] The negative electrode mixture 5 contains zinc powder, a potassium hydroxide aqueous solution, and a gelling agent, and is in a gel state. The negative electrode mixture 5 is disposed inside the positive electrode mixture 3. The zinc powder contained in the negative electrode active material may be replaced with zinc alloy powder formed from a zinc alloy containing zinc.

[0015] The current collector rod 6 is made of a conductor and has a rod shape. The current collector rod 6 is inserted into the negative electrode mixture 5 from the opening 18 side along the central axis of the positive electrode can 2.

[0016] The separator 7 is made of an insulating material such as vinylon or pulp. The separator 7 is formed in a cylindrical shape with a bottom, and includes a tubular portion 21 and a bottom surface 22. The tubular portion 21 is formed in a cylindrical shape. The bottom surface 22 closes one end of the tubular portion 21.

[0017] The separator 7 is disposed inside the positive electrode can 2 so that the cylindrical tube portion 21 is coaxial with the positive electrode can 2. The bottom surface 22 of the separator 7 abuts against the bottom surface 16 of the positive electrode can 2. The tube portion 21 of the separator 7 is disposed between the positive electrode mixture 3 and the negative electrode mixture 5. That is, inside the positive electrode can 2, the positive electrode mixture 3 is disposed on the outside of the separator 7, and the negative electrode mixture 5 is disposed on the inside of the separator 7. The negative electrode mixture 5 is insulated from the positive electrode mixture 3 and the positive electrode can 2 by the separator 7.

[0018] An electrolyte solution is poured into the positive electrode can 2. The electrolyte solution is an aqueous solution containing potassium hydroxide (KOH). The electrolyte solution permeates the positive electrode mixture 3, the negative electrode mixture 5, and the separator 7.

[0019] 2 is a partially enlarged cross-sectional view of portion A shown in FIG. 1. Gasket 14 is made of an insulator such as nylon. Gasket 14 closes opening 18 of positive electrode can 2. Gasket 14 has a support portion 41, an outer peripheral portion 42, a buffer portion 43, and a clamping portion 44.

[0020] A through-hole 41a is formed in the support portion 41, and is coaxial with the positive electrode can 2. A current collecting rod 6 is inserted into the through-hole 41a. The current collecting rod 6 is supported by the gasket 14 by being inserted into the through-hole 41a.

[0021] The outer peripheral portion 42 is formed in a ring shape and is provided on the outer periphery of the support portion 41. The portion of the outer peripheral portion 42 that connects to the support portion 41 is a valve portion 42a that is thinner than the other portions. The valve portion 42a functions as a safety valve that ruptures when the internal pressure of the alkaline battery 1 increases.

[0022] A first opposing portion 421 and a second opposing portion 422 are formed on a first surface 42b of the outer circumferential portion 42 facing the positive electrode terminal 17. The first opposing portion 421 and the second opposing portion 422 are formed integrally with the gasket 14. The first opposing portion 421 and the second opposing portion 422 are formed in an annular shape centered on the central axis C. The first opposing portion 421 is formed more inward than the second opposing portion 422. A gap is formed between the first opposing portion 421 and the second opposing portion 422.

[0023] An end portion of the separator 7 facing the negative electrode terminal plate 12 is inserted into the gap between the first facing portion 421 and the second facing portion 422. The first facing portion 421 faces the inner circumferential surface 7a of the separator 7 (tubular portion 21) at the end portion of the separator 7 facing the negative electrode terminal plate 12. The second facing portion 422 faces the outer circumferential surface 7b of the separator 7 (tubular portion 21) at the end portion of the separator 7 facing the negative electrode terminal plate 12.

[0024] The buffer portion 43 is provided on the outer periphery of the outer peripheral portion 42 and is formed in an annular shape. The buffer portion 43 has a bent portion 43a formed in a cross section that is bent toward the positive electrode terminal 17 side or the negative electrode terminal plate 12 side, and the bent portion 43a has a recessed portion 43b formed in the bent portion 43a that is recessed toward the positive electrode terminal 17 side or the negative electrode terminal plate 12 side. The buffer portion 43 relieves the compressive force applied to the gasket 14 in the radial direction by deformation of the bent portion 43a. In other words, the first opposing portion 421 and the second opposing portion 422 formed on the outer periphery portion 42 are provided at positions that avoid the buffer portion 43.

[0025] The clamping portion 44 is provided on the outer periphery of the buffer portion 43 and is formed in a ring shape. As shown in Fig. 2, the clamping portion 44 is sandwiched and held between the positive electrode can 2 and the negative electrode terminal plate 12. By sandwiching the clamping portion 44 between the positive electrode can 2 and the negative electrode terminal plate 12, the positive electrode can 2 and the negative electrode terminal plate 12 are electrically insulated from each other.

[0026] The negative electrode terminal plate 12 is made of a conductor such as a metal. The negative electrode terminal plate 12 is provided in the opening 18 of the positive electrode can 2. More specifically, the negative electrode terminal plate 12 is provided on the opposite side of the separator 7 with a gasket in between. A certain region of the negative electrode terminal plate 12 extending from the portion overlapping the central axis of the cylindrical portion 15 of the positive electrode can 2 toward the outer periphery serves as the negative electrode terminal 13. One end of the current collector rod 6 is joined to the negative electrode terminal plate 12. This forms a current collector in which the current collector rod 6, the gasket 14, and the negative electrode terminal plate 12 are integrated.

[0027] <First Modification of First Embodiment> FIG. 3 is a cross-sectional view of an alkaline battery according to a first modification of the first embodiment, and is a partially enlarged cross-sectional view of a portion corresponding to portion A shown in FIG.

[0028] The alkaline battery 1 according to the first modification is provided with a cap 23 having an annular groove 23a formed therein into which the end of the separator 7 facing the negative electrode terminal plate 12 is inserted. The cap 23 may or may not abut against the first surface 42b of the outer circumferential portion 42 of the gasket 14. In the first modification, one wall surface of the groove 23a serves as a first opposing portion that faces the inner circumferential surface 7a of the separator 7, and the other wall surface of the groove 23a serves as a second opposing portion that faces the outer circumferential surface 7b of the separator 7.

[0029] Second Embodiment Fig. 4 is a cross-sectional view of an alkaline battery according to a second embodiment, and is a partially enlarged cross-sectional view of a portion corresponding to portion A shown in Fig. 1. The same components as those in the first embodiment are designated by the same reference numerals, and detailed descriptions thereof will be omitted.

[0030] In the alkaline battery 1 according to the second embodiment, a certain region of the cylindrical tube portion 21 of the separator 7 extending from the end on the negative electrode terminal plate 12 side to the positive electrode terminal 17 side serves as a contact region 30 that contacts the first surface 42b of the outer periphery of the gasket 14. As shown in Fig. 4, the contact region 30 contacts the gasket 14 and curves inward.

[0031] The alkaline battery 1 according to the second embodiment includes a first annular portion 24. The first annular portion 24 extends outward from near the connection between the first surface 42b of the outer peripheral portion 42 and the outer peripheral surface of the support portion 41. In a cross section taken along a plane including the central axis C, the first annular portion 24 is inclined so that the first annular portion 24 approaches the positive electrode terminal 17 as it extends outward, and a gap is formed between the first annular portion 24 and the first surface 42b. In addition, in a cross section taken along a plane including the central axis C, the first annular portion 24 extends linearly outward.

[0032] The first annular portion 24 is formed in an annular shape separate from the gasket 14. The first annular portion 24 is held by a support portion 41 fitted inside the annular shape. The first annular portion 24 is made of brass, for example. The first annular portion 24 may also be formed integrally with the gasket 14.

[0033] The end of the separator 7 facing the negative electrode terminal plate 12 is inserted between the first annular portion 24 and the first surface 42b. In the alkaline battery 1 according to the second embodiment, the first annular portion 24 serves as a first opposing portion opposing the inner circumferential surface 7a of the separator 7, and the first surface 42b of the outer circumferential portion 42 of the gasket 14 serves as a second opposing portion opposing the outer circumferential surface 7b of the separator 7.

[0034] <First Modification of Second Embodiment> FIG. 5 is a cross-sectional view of an alkaline battery according to a first modification of the second embodiment, and is a partially enlarged cross-sectional view of a portion corresponding to portion A shown in FIG.

[0035] In the alkaline battery 1 according to the first variant of embodiment 2, the first annular portion 24 has a stepped shape (crank shape) in the cross-sectional shape cut along a plane including the central axis C, thereby forming a gap between it and the first surface 42b.

[0036] 4, the first annular portion 24 may be formed separately from the gasket 14 or may be formed integrally with the gasket 14. When the first annular portion 24 is formed separately, it is made of brass, for example. The end of the separator 7 facing the negative electrode terminal plate 12 is inserted between the first annular portion 24 and the first surface 42b, so that the first annular portion 24 forms a first opposing portion facing the inner circumferential surface 7a of the separator 7, and the first surface 42b of the outer circumferential portion 42 of the gasket 14 forms a second opposing portion facing the outer circumferential surface 7b of the separator 7.

[0037] <Second Modification of Second Embodiment> FIG. 6 is a cross-sectional view of an alkaline battery according to a second modification of the second embodiment, and is a partially enlarged cross-sectional view of a portion corresponding to portion A shown in FIG.

[0038] In the alkaline battery 1 according to the second modification of the second embodiment, the first annular portion 24 is curved so as to be convex toward the outer circumferential portion 42 in a cross section cut along a plane including the central axis C.

[0039] 4, the first annular portion 24 may be formed separately from the gasket 14 or may be formed integrally with the gasket 14. When the first annular portion 24 is formed separately, it is made of brass, for example. The end of the separator 7 facing the negative electrode terminal plate 12 is inserted between the first annular portion 24 and the first surface 42b, so that the first annular portion 24 forms a first opposing portion facing the inner circumferential surface 7a of the separator 7, and the first surface 42b of the outer circumferential portion 42 of the gasket 14 forms a second opposing portion facing the outer circumferential surface 7b of the separator 7.

[0040] Since the first annular portion 24 is curved so as to be convex toward the outer circumferential portion 42, the gap between the first annular portion 24 and the first surface 42b becomes wider on the outside, which makes it easier for the end of the separator 7 on the negative electrode terminal plate 12 side to fit into the gap.

[0041] <Third Modification of Second Embodiment> FIG. 7 is a cross-sectional view of an alkaline battery according to a third modification of the second embodiment, and is a partially enlarged cross-sectional view of a portion corresponding to portion A shown in FIG.

[0042] In the alkaline battery 1 according to the third modification of the second embodiment, in a cross section taken along a plane including the central axis C, the first annular portion 24 is curved so as to be convex toward the outer peripheral portion 42, similar to the second modification of the second embodiment. In addition, the first annular portion 24 is curved so that the tangent direction of the outer end portion is substantially parallel to the central axis C.

[0043] 4, the first annular portion 24 may be formed separately from the gasket 14 or may be formed integrally with the gasket 14. When the first annular portion 24 is formed separately, it is made of brass, for example. The end of the separator 7 facing the negative electrode terminal plate 12 is inserted between the first annular portion 24 and the first surface 42b, so that the first annular portion 24 forms a first opposing portion facing the inner circumferential surface 7a of the separator 7, and the first surface 42b of the outer circumferential portion 42 of the gasket 14 forms a second opposing portion facing the outer circumferential surface 7b of the separator 7.

[0044] Since the outer end is curved so that the tangent direction of the outer end is approximately parallel to the central axis C, the gap between the first annular portion 24 and the first surface 42b is wider on the outer side, which makes it easier for the end of the separator 7 on the negative electrode terminal plate 12 side to fit into the gap.

[0045] <Fourth Modification of Second Embodiment> FIG. 8 is a cross-sectional view of an alkaline battery according to a fourth modification of the second embodiment, and is a partially enlarged cross-sectional view of a portion corresponding to portion A shown in FIG.

[0046] In the alkaline battery 1 according to the fourth modification of the second embodiment, the first annular portion 24 is curved so as to be convex toward the positive electrode terminal 17 in a cross section cut along a plane including the central axis C.

[0047] 4, the first annular portion 24 may be formed separately from the gasket 14 or may be formed integrally with the gasket 14. When the first annular portion 24 is formed separately, it is made of brass, for example. The end of the separator 7 facing the negative electrode terminal plate 12 is inserted between the first annular portion 24 and the first surface 42b, so that the first annular portion 24 forms a first opposing portion facing the inner circumferential surface 7a of the separator 7, and the first surface 42b of the outer circumferential portion 42 of the gasket 14 forms a second opposing portion facing the outer circumferential surface 7b of the separator 7.

[0048] Because the first annular portion 24 is curved so as to be convex toward the positive electrode terminal 17, the gap between the first annular portion 24 and the first surface 42b is narrower on the outside. Therefore, the gap between the first annular portion 24 and the inner circumferential surface 7a of the separator 7 and the gap between the first surface 42b and the outer circumferential surface 7b of the separator 7 are also narrower. This makes it less likely for the negative electrode mixture provided on the inside of the separator 7 to enter the gap between the first annular portion 24 and the inner circumferential surface 7a of the separator 7 or the gap between the first surface 42b and the outer circumferential surface 7b of the separator 7, for example.

[0049] <Fifth Modification of Second Embodiment> FIG. 9 is a cross-sectional view of an alkaline battery according to a fifth modification of the second embodiment, and is a partially enlarged cross-sectional view of a portion corresponding to portion A shown in FIG.

[0050] In the alkaline battery 1 according to the fifth modification of the second embodiment, a cylindrical tubular portion 25 is provided that extends from the inner edge of the annular first annular portion 24 toward the positive electrode terminal 17. The first annular portion 24 and the tubular portion 25 are integrally formed. The end of the tubular portion 25 that faces the positive electrode terminal 17 is bent inward. The inner peripheral surface of the tubular portion 25 abuts against the outer peripheral surface of the support portion 41. This makes it difficult for the first annular portion 24 to fall off the support portion 41.

[0051] 4, the first annular portion 24 may be formed separately from the gasket 14 or may be formed integrally with the gasket 14. When the first annular portion 24 is formed separately, it is made of brass, for example. The end of the separator 7 facing the negative electrode terminal plate 12 is inserted between the first annular portion 24 and the first surface 42b, so that the first annular portion 24 forms a first opposing portion facing the inner circumferential surface 7a of the separator 7, and the first surface 42b of the outer circumferential portion 42 of the gasket 14 forms a second opposing portion facing the outer circumferential surface 7b of the separator 7.

[0052] The cross-sectional shape of the first annular portion 24 cut along a plane including the central axis C may be any of the shapes exemplified in the second embodiment (FIGS. 4 to 9).

[0053] <Sixth Modification of Second Embodiment> FIG. 10 is a cross-sectional view of an alkaline battery according to a sixth modification of the second embodiment, and is a partially enlarged cross-sectional view of a portion corresponding to portion A shown in FIG.

[0054] In an alkaline battery 1 according to a sixth modification of the second embodiment, the second annular portion 26 is provided closer to the first surface 42b than the first annular portion 24. The second annular portion 26 is formed in an annular shape. The second annular portion 26 is connected to the first annular portion 24 at an end portion thereof on the support portion 41 side. In a cross section cut along a plane including the central axis C, the first annular portion 24 and the second annular portion 26 form a V-shape.

[0055] 4, the first annular portion 24 and the second annular portion 26 may be formed separately from the gasket 14 or may be formed integrally with the gasket 14. When the first annular portion 24 and the second annular portion 26 are formed separately, they are made of brass, for example. The end of the separator 7 facing the negative electrode terminal plate 12 is inserted between the first annular portion 24 and the second annular portion 26, so that the first annular portion 24 forms a first opposing portion facing the inner circumferential surface 7a of the separator 7, and the second annular portion 26 forms a second opposing portion facing the outer circumferential surface 7b of the separator 7.

[0056] Since the first annular portion 24 and the second annular portion 26 are connected to form a V-shaped cross section, the strength is improved compared to when only the first annular portion 24 is used.

[0057] Third Embodiment Fig. 11 is a cross-sectional view of an alkaline battery according to a third embodiment, which is a partially enlarged cross-sectional view of a portion corresponding to portion A shown in Fig. 1. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.

[0058] In the alkaline battery 1 according to the third embodiment, as in the second embodiment, a certain region of the cylindrical tube portion 21 of the separator 7 extending from the end on the negative electrode terminal plate 12 side to the positive electrode terminal 17 side serves as a contact region 30 that contacts the first surface 42b of the outer periphery of the gasket 14. As shown in Fig. 11 , the contact region 30 contacts the gasket 14 and curves inward.

[0059] In the gasket 14, a groove 41b extending in an annular shape is formed on the outer peripheral surface of the support portion 41 at the connection portion with the first surface 42b of the outer peripheral portion 42. The end portion of the separator 7 on the negative electrode terminal plate 12 side is inserted into the groove 41b.

[0060] In the alkaline battery 1 according to the third embodiment, one wall surface of the groove 41b forms a first opposing portion that faces the inner circumferential surface 7a of the separator 7, and the other wall surface forms a second opposing portion that faces the outer circumferential surface of the separator 7. Although the example in which the cross section of the groove 41b taken along a plane including the central axis C is V-shaped has been shown, the cross section is not limited to this. Any cross section having a wall surface that forms the first opposing portion and a wall surface that forms the second opposing portion may be used, for example, a U-shape or a C-shape.

[0061] Since the first opposing portion and the second opposing portion can be provided simply by forming the groove 41b in the support portion 41, the number of parts can be reduced and the structure can be simplified.

[0062] [Evaluation Test of Comparative Examples and Examples] In an alkaline battery 1 in which a gelled negative electrode mixture 5 is provided inside the separator 7, for example, when the battery is dropped with the negative electrode terminal plate 12 side facing downward and hits the floor, the negative electrode mixture 5 that has flowed toward the gasket 14 may leak outside the separator 7. If the negative electrode mixture 5 leaks outside the separator 7, the negative electrode mixture 5 and the positive electrode mixture 3 may come into contact with each other, causing a short circuit.

[0063] Here, comparative experiments were carried out using Comparative Examples 1 and 2 and Examples 1 to 4. The alkaline batteries according to Comparative Examples 1 and 2 and Examples 1 to 4 were made using AA size batteries of LR6.

[0064] First, the configuration of an alkaline battery according to a comparative example will be described. Fig. 12 is a cross-sectional view of an alkaline battery according to comparative example 1, and is a partially enlarged cross-sectional view of a portion corresponding to portion A shown in Fig. 1. In alkaline battery 111 according to comparative example 1, separator 7 is curved to provide a contact region 30 that abuts against first surface 42b, but does not have first annular portion 24 as in embodiment 2. That is, alkaline battery 111 according to comparative example 1 does not have a first opposing portion that faces inner circumferential surface 7a of separator 7.

[0065] 13 is a cross-sectional view of an alkaline battery according to Comparative Example 2, and is a partially enlarged cross-sectional view of a portion corresponding to portion A shown in FIG. 1. In alkaline battery 112 according to Comparative Example 2, the shape of buffer portion 143 formed on gasket 14 is different from that of alkaline batteries 1 according to Embodiments 1 and 2. Specifically, bent portion 143a is formed to form recessed portion 143b recessed toward negative electrode terminal plate 12.

[0066] The end of separator 7 on the negative electrode terminal plate 12 side is not curved, and is fitted into a recess 143b formed in buffer part 143. That is, the end of separator 7 is held by bent part 143a of gasket 14.

[0067] In addition, in the alkaline battery 112 according to Comparative Example 2, the wall surfaces of the recess 143b face the inner circumferential surface 7a and the outer circumferential surface 7b of the separator 7. In other words, in the alkaline battery 112 according to Comparative Example 2, the portion facing the inner circumferential surface 7a of the separator 7 (one wall surface of the recess 143b) and the portion facing the outer circumferential surface 7b (the other wall surface of the recess 143b) are located at positions that overlap with the buffer section 143 when viewed along the central axis C.

[0068] Next, the configuration of the alkaline battery 1 according to Examples 1 to 4 will be described. First, the alkaline battery 1 according to Example 1 has the configuration shown in Fig. 2 as Embodiment 1. As shown in Fig. 2, the height of the first opposing portion 421 from the first surface 42b is 1.2 mm, and the height of the second opposing portion 422 from the first surface 42b is 1.0 mm.

[0069] The alkaline battery 1 according to Example 2 has the configuration shown in Fig. 3 as a first modification of Embodiment 1. As shown in Fig. 3, the depth of the groove 23a is 1.0 mm. That is, the height of the wall surfaces of the groove 23a that form the first and second opposing portions is 1.0 mm.

[0070] The alkaline battery 1 according to Example 3 has the configuration shown in Fig. 4 as Embodiment 2. As shown in Fig. 4, the length of the portion of the first annular portion 24 that forms a gap with the first surface 42b is 1.0 mm. In other words, the length of the portion of the first annular portion 24 that forms the first opposing portion is 1.0 mm.

[0071] The alkaline battery 1 according to Example 4 has the configuration shown in FIG. 11 as embodiment 3. As shown in FIG. 11, the height of the wall surfaces of groove 41b is 0.8 mm. That is, the height of the wall surfaces of groove 41b that form the first opposing portion and the second opposing portion is 0.8 mm. The angle between the wall surfaces of groove 41b is 60°.

[0072] Figure 14 shows the results of the evaluation tests. The following two types of evaluation tests were conducted on alkaline batteries 1,111, and 112. In the first test, tests were conducted under the transportation and vibration conditions specified in JIS C 8514 B-2 to confirm the decrease in open circuit voltage (OCV) caused by the leakage of gel and zinc particles (negative electrode mixture 5). In the second test, alkaline batteries 1,111, and 112 were dropped to confirm the decrease in open circuit voltage (OCV) caused by the leakage of gel and zinc particles (negative electrode mixture 5). In this test, alkaline batteries 1,111, and 112 were dropped five times from a height of 1 meter onto concrete with the negative electrode terminal 13 facing downward.

[0073] The evaluation results in FIG. 14 are shown as (number of alkaline batteries with OCV reduction) / (number of alkaline batteries tested).

[0074] As shown in FIG. 14, in the alkaline batteries 111 according to Comparative Example 1, a decrease in OCV was observed in some of the alkaline batteries 111 when they were tested under the transportation and vibration conditions of JIS C 8514 B-2 and when they were subjected to a drop test.

[0075] In addition, in the alkaline battery 112 according to Comparative Example 2, there was no decrease in OCV when tested under the transportation and vibration conditions of JIS C 8514 B-2, but a decrease in OCV was observed in some cases when a drop test was performed.

[0076] On the other hand, in the alkaline batteries 1 of Examples 1 and 2, when tested under the transportation and vibration conditions of JIS C 8514 B-2, there was no decrease in OCV, and when tested under the drop test, although some decrease in OCV was observed, the number of such decrease was smaller than in Comparative Examples 1 and 2.

[0077] Therefore, it can be seen that, as in the alkaline battery 1 according to Example 1, by forming the first opposing portion 421 and the second opposing portion 422 on the gasket 14, it is possible to prevent leakage of the negative electrode mixture 5.

[0078] Furthermore, it can be seen that, as in the alkaline battery 1 according to Example 2, by inserting the end of the separator 7 into the groove 23a formed in the cap 23, leakage of the negative electrode mixture 5 can be prevented.

[0079] Furthermore, in the alkaline batteries 1 according to Examples 3 and 4, no decrease in OCV was observed when the batteries were tested under the transportation and vibration conditions of JIS C 8514 B-2 or when they were subjected to a drop test.

[0080] Therefore, it can be seen that, as in the alkaline battery 1 of Example 3, by bending the end of the separator 7 to abut against the gasket 14 and providing a first annular portion 24 facing the inner surface 7a of the separator 7, it is possible to further suppress leakage of the negative electrode mixture 5.

[0081] Furthermore, as in the alkaline battery 1 of Example 4, by bending the end of the separator 7 to abut against the gasket 14 and inserting the end of the separator 7 into the groove 41b formed in the support portion 41, it can be seen that the occurrence of leakage of the negative electrode mixture 5 can be further suppressed.

[0082] [Summary of effects] The alkaline battery 1 according to the first to third embodiments includes a cylindrical cathode can 2 with a bottom and a cathode terminal 17 formed on the bottom surface, a cylindrical cathode mixture 3 provided inside the cathode can 2 and arranged coaxially with the cathode can 2, a cylindrical separator 7 provided on the inner periphery of the cathode mixture 3, a gelled anode mixture 5 filled on the inner periphery of the separator 7, a current collector 6 inserted into the anode mixture 5, a support portion 41 formed with a through hole 41a through which the current collector 6 passes, and an annular outer peripheral portion 42 provided on the outer periphery of the support portion 41, and a gasket that closes an opening 18 in the cathode can 2. a first opposing portion that faces an inner circumferential surface 7a of the separator 7 at the end of the separator 7 that faces the negative electrode terminal plate 12, and a second opposing portion that faces an outer circumferential surface 7b of the separator 7 at the end of the separator 7 that faces the negative electrode terminal plate 12, and a buffer portion 43 that buffers compressive force applied in the radial direction is formed on the outer circumferential portion 42, and the first opposing portion and the second opposing portion are located at positions that avoid the buffer portion 43 when viewed along the central axis C of the positive electrode can 2.

[0083] This allows the first opposing portion and the second opposing portion to face the inner circumferential surface 7a and the outer circumferential surface 7b of the separator 7, thereby preventing the negative electrode mixture from leaking outside the separator 7. This makes it possible to prevent short circuits and a decrease in OCV caused by leakage of the negative electrode mixture 5.

[0084] Furthermore, the first opposing portion and the second opposing portion may protrude from a first surface 42b of the outer circumferential portion 42 that faces the positive electrode terminal 17, and may be formed integrally with the outer circumferential portion 42. Because the first opposing portion and the second opposing portion are formed integrally with the outer circumferential portion 42, the number of parts can be reduced.

[0085] The battery may further include a cap 23 having an annular groove 23a formed therein into which the end of the separator 7 facing the negative electrode terminal plate 12 is inserted, with one wall surface of the groove 23a serving as a first opposing portion and the other wall surface serving as a second opposing portion. With the simple configuration of providing the cap 23 on the end of the separator 7, it is possible to prevent short circuits and a decrease in OCV due to leakage of the negative electrode mixture 5.

[0086] Separator 7 has a certain region from the end on the negative electrode terminal plate 12 side to the positive electrode terminal 17 side that curves inward to form a contact region 30 that contacts the outer periphery 42, and further includes a first annular portion 24 that is annular and extends outward from near the connection between a first surface 42b of outer periphery 42 that faces the positive electrode terminal 17 side and the outer periphery of support portion 41, and first annular portion 24 may be the first opposing portion.

[0087] The contact region of the separator 7 is curved and folded inward, which prevents the negative electrode mixture 5 from leaking outside the separator 7. Furthermore, the first annular portion 24 is provided as a first opposing portion that faces the inner circumferential surface 7a of the separator 7, which further prevents the negative electrode mixture 5 from leaking outside the separator 7. This prevents short circuits and a decrease in OCV due to leakage of the negative electrode mixture 5.

[0088] Furthermore, the first surface 42b of the outer peripheral portion 42 may serve as the second opposing portion. Since the first surface 42b of the outer peripheral portion 42 can serve as the second opposing portion without adding any special configuration, the structure can be simplified.

[0089] Furthermore, the first annular portion 24 may have a cross-sectional shape that extends linearly when cut along a plane that includes the central axis C. Forming the first annular portion 24 in a simple shape in which the cross-sectional shape extends linearly can facilitate the manufacture of the first annular portion 24.

[0090] Furthermore, the first annular portion 24 may be curved so that the cross-sectional shape, when cut along a plane including the central axis C, is convex toward the outer peripheral portion 42. By curving the cross-sectional shape of the first annular portion 24 so that it is convex toward the outer peripheral portion 42, the gap between the first annular portion 24 and the first surface 42b of the outer peripheral portion 42 becomes larger at the outer portion, making it easier to insert the end of the separator 7 into the gap. Therefore, during the manufacturing process of the alkaline battery 1, failure to insert the end of the separator 7 into the gap is less likely to occur.

[0091] Furthermore, the first annular portion 24 may be curved so that the cross-sectional shape, when cut along a plane including the central axis C, is convex toward the positive electrode terminal 17. By curving the cross-sectional shape of the first annular portion 24 so that it is convex toward the positive electrode terminal 17, the gap between the first annular portion 24 and the first surface 42b of the outer peripheral portion 42 at the outer portion is reduced. This reduces the gap between the first opposing portion and the separator 7 and the gap between the second opposing portion and the separator, more reliably preventing leakage of the negative electrode mixture 5 beyond the separator 7.

[0092] Furthermore, the first annular portion 24 may have a stepped cross section taken along a plane including the central axis C. The stepped cross section can improve the strength of the first annular portion 24.

[0093] Furthermore, the first annular portion 24 may be formed separately from the gasket 14. Because it is formed separately from the gasket 14, it is not necessary to consider the shape of the mold used to produce the gasket 14 when designing the shape of the first annular portion 24. This increases the degree of freedom in designing the shape and material of the first annular portion 24.

[0094] Furthermore, the first annular portion 24 may be formed integrally with the gasket 14. Since the first annular portion 24 is formed integrally with the gasket 14, the number of parts can be reduced.

[0095] Furthermore, the device may further include a second annular portion 26 that is provided closer to the first surface 42b than the first annular portion 24 and is connected to the first annular portion 24 at an end portion on the support portion 41 side, with the second annular portion 26 serving as the second opposing portion. By connecting the first annular portion 24 and the second annular portion 26, the number of parts can be reduced compared to when they are provided separately. Furthermore, the strength of the structure in which the first annular portion 24 and the second annular portion 26 are connected can be improved.

[0096] Separator 7 has a certain region from the end on the negative electrode terminal plate 12 side to the positive electrode terminal 17 side that curves inward to form contact region 30 that contacts outer periphery 42, and an annular groove 41b is formed in the outer periphery of support portion 41 at a connection portion with first surface 42b of outer periphery 42 that faces positive electrode terminal 17, with one wall surface of groove 41b serving as a first opposing portion and the other wall surface serving as a second opposing portion. Since the wall surfaces of groove 41b formed in support portion 41 of gasket 14 can serve as the first opposing portion and the second opposing portion without adding a separate component, the number of parts can be reduced. [Explanation of symbols]

[0097] 1,111,112 alkaline batteries 2 Positive electrode can 3 Positive electrode mixture 5. Negative electrode mixture 6 collector rods 7 Separator 7a Inner surface 7b Outer surface 12 Negative terminal plate 13 Negative terminal 14 Gasket 15 Cylinder part 16 Bottom 17 Positive terminal 18 Aperture 21 Cylinder part 22 bottom 23 Cap 23a Groove 24 First annular section 25 Cylinder 26 Second annular section 30 Contact area 41 Support part 41a Through hole 41b Groove 42 Outer periphery 42a Valve part 42b First Side 421 First opposing part 422 Second opposing part 43,143 Buffer section 43a,143a Bend part 43b,143b recess 44 Hostage Department

Claims

1. a cylindrical positive electrode can with a bottom and a positive electrode terminal formed on the bottom surface; a cylindrical positive electrode mixture provided inside the positive electrode can and arranged coaxially with the positive electrode can; a cylindrical separator provided on the inner circumferential side of the positive electrode mixture; a gelled negative electrode mixture filled on the inner circumferential side of the separator; a current collector rod inserted into the negative electrode mixture; a gasket having a support portion formed with a through hole through which the current collecting rod passes and an annular outer peripheral portion provided on the outer periphery of the support portion, the gasket closing the opening of the positive electrode can; a negative electrode terminal plate provided on the opposite side of the separator with the gasket in between; a first opposing portion that faces an inner circumferential surface of the separator at an end portion of the separator that is on the negative electrode terminal plate side; a second opposing portion that faces an outer peripheral surface of the separator at an end of the separator that is on the negative electrode terminal plate side, A buffer portion is formed on the outer circumferential portion to relieve a compressive force applied in the radial direction, an alkaline battery in which the first opposing portion and the second opposing portion are provided at positions that avoid the buffer portion when viewed along the central axis of the positive electrode can;

2. 2. The alkaline battery according to claim 1, wherein the first opposing portion and the second opposing portion protrude from a first surface of the outer circumferential portion facing the positive electrode terminal and are formed integrally with the outer circumferential portion.

3. a cap having an annular groove formed therein into which an end of the separator on the negative electrode terminal plate side is inserted; 2. The alkaline battery according to claim 1, wherein one wall surface of the groove serves as the first opposing portion and the other wall surface serves as the second opposing portion.

4. a certain region of the separator extending from an end portion on the negative electrode terminal plate side to a positive electrode terminal side is curved inward to form a contact region that contacts the outer circumferential portion, a first annular portion extending outward from a vicinity of a connection between a first surface of the outer circumferential portion facing the positive electrode terminal and an outer circumferential surface of the support portion, 2. The alkaline battery according to claim 1, wherein the first annular portion is the first opposing portion.

5. 5. The alkaline battery according to claim 4, wherein the first surface of the outer periphery serves as the second opposing portion.

6. The alkaline battery according to claim 5 , wherein the first annular portion has a cross-sectional shape that extends linearly when cut along a plane including the central axis.

7. 6. The alkaline battery according to claim 5, wherein the first annular portion has a cross-sectional shape cut along a plane including the central axis that is curved so as to be convex toward the outer periphery.

8. The alkaline battery according to claim 5 , wherein the first annular portion has a cross-sectional shape cut along a plane including the central axis that is curved so as to be convex toward the positive electrode terminal.

9. 6. The alkaline battery according to claim 5, wherein the first annular portion has a stepped cross section cut along a plane including the central axis.

10. 10. The alkaline battery according to claim 4, wherein the first annular portion is formed separately from the gasket.

11. 10. The alkaline battery according to claim 4, wherein the first annular portion is integrally formed with the gasket.

12. a second annular portion provided closer to the first surface than the first annular portion and connected to the first annular portion at an end portion on the support portion side, 5. The alkaline battery according to claim 4, wherein the second annular portion serves as the second opposing portion.

13. a certain region of the separator extending from an end portion on the negative electrode terminal plate side to a positive electrode terminal side is curved inward to form a contact region that contacts the outer circumferential portion, An alkaline battery as described in claim 1, wherein a groove extending in an annular shape is formed on the outer peripheral surface of the support portion at the connection portion with a first surface of the outer peripheral portion facing the positive terminal, one wall surface of the groove being the first opposing portion and the other wall surface being the second opposing portion.

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