Battery

Abstract

This prevents internal short circuits from occurring. [Solution] The battery comprises a positive electrode can, a positive electrode disposed in an internal space formed in the positive electrode can, a negative electrode disposed in a negative electrode filling hole formed in the positive electrode, a separator disposed between the negative electrode and the positive electrode, a negative electrode terminal plate disposed at the opening of the positive electrode can, a current collector rod embedded in the negative electrode, and a sealing gasket 14. The sealing gasket 14 has a gasket boss portion 31 fixed to the current collector rod, a gasket peripheral portion 33 that seals the gap formed between the negative electrode terminal plate and the positive electrode can, and a gasket flange portion 32 formed between the gasket boss portion 31 and the gasket peripheral portion 33. Eight radial protrusions 41 are formed on the separator-facing surface 34 of the gasket flange portion 32 that faces the separator, arranged along a circle 42 surrounding the gasket boss portion 31.

Description

Technical Field

[0001] The technology of the present disclosure relates to batteries.

Background Art

[0002] When an alkaline manganese dry battery is subjected to vibration or impact, a part of the gel-like negative electrode disposed inside the separator may flow out to the outside of the separator through the gap between the opening of the separator and the gasket, and an internal short circuit may occur where the negative electrode makes electrical contact with the positive electrode. To prevent an internal short circuit, a first alkaline manganese dry battery is known in which the opening of the separator is bent inward and the opening of the separator is constricted (Patent Documents 1 to 3). Also, to prevent an internal short circuit, a second alkaline manganese dry battery is known in which the gasket sandwiches the opening end of the separator so that no gap is formed between the separator and the gasket, and the opening end of the separator is fixed to the gasket (Patent Document 4).

Prior Art Documents

Patent Documents

[0003] [[ID=2l]]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the first alkaline manganese dry cell, irregularities formed at the separator's opening can create a gap between the gasket and the separator, allowing the gel-like negative electrode to leak out through this gap. In the second alkaline manganese dry cell, when an impact is applied and the gel-like negative electrode moves, the pressure from the gel-like negative electrode can rupture the separator, allowing the gel-like negative electrode to leak out through the rupture. Therefore, internal short circuits can occur even in these alkaline manganese dry cells.

[0005] The disclosed technology has been made in view of the above and aims to provide a battery that prevents internal short circuits from occurring. [Means for solving the problem]

[0006] A battery according to one aspect of the present disclosure comprises a positive electrode can, a positive electrode disposed in an internal space formed in the positive electrode can, a negative electrode disposed in a negative electrode filling hole formed in the positive electrode, a separator disposed between the negative electrode and the positive electrode, a negative electrode terminal plate disposed in an opening of the positive electrode can, a current collector rod embedded in the negative electrode, and a gasket, wherein the gasket has a boss portion fixed to the current collector rod, a peripheral portion that closes the gap formed between the negative electrode terminal plate and the positive electrode can, and a flange portion formed between the boss portion and the peripheral portion, and a plurality of radial protrusions arranged along a circle surrounding the boss portion are formed on the separator-facing surface of the flange portion that faces the separator. [Effects of the Invention]

[0007] The disclosed battery can prevent internal short circuits from occurring. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a cross-sectional view showing the battery of Example 1. [Figure 2] Figure 2 is an enlarged cross-sectional view showing a portion of the battery of Example 1. [Figure 3] Figure 3 is a bottom view showing the sealing gasket of the battery in Example 1. [Figure 4] Figure 4 shows a cross-sectional view along line AA in Figure 3, illustrating the radial projections. [Figure 5] Figure 5 is a perspective view showing the side of the separator. [Figure 6] Figure 6 is a perspective view showing the separator's open end portion and the eight radial protrusions. [Figure 7] Figure 7 is a cross-sectional view showing the gap formed between the separator and the sealing gasket. [Figure 8] Figure 8 is a cross-sectional view showing the radial projections of the sealing gasket of a modified battery. [Figure 9] Figure 9 is a cross-sectional view showing the radial projections of the sealing gasket of the battery in Example 2. [Figure 10] Figure 10 is a bottom view showing the sealing gasket of the battery in Example 3. [Figure 11] Figure 11 is a bottom view showing the sealing gasket of the battery in Example 4. [Figure 12] Figure 12 is a bottom view showing the sealing gasket of the battery in Example 4. [Figure 13] Figure 13 shows a cross-sectional view of the BB line in Figure 12, illustrating the radial protrusions of the battery in Example 4. [Figure 14] Figure 14 is a cross-sectional view showing the battery of Comparative Example 1. [Figure 15] Figure 15 is a bottom view showing the sealing gasket of the battery in Comparative Example 1. [Figure 16] Figure 16 is a cross-sectional view showing the battery of Comparative Example 2. [Modes for carrying out the invention]

[0009] The battery according to the embodiment disclosed in the present application will be described below with reference to the drawings. Note that the technology of the present disclosure is not limited by the following description. Also, in the following description, the same reference numerals are assigned to the same components, and duplicate explanations are omitted.

Example

[0010] The battery 1 of Example 1 is an alkaline manganese dry battery. As shown in FIG. 1, it includes a battery case 2, a positive electrode 3, a negative electrode 5, a current collector rod 6, and a separator 7. FIG. 1 is a cross-sectional view showing the battery 1 of Example 1. The battery case 2 includes a positive electrode can 11, a negative electrode terminal plate 12, and a sealing gasket 14. The positive electrode can 11 is formed of metal. The positive electrode can 11 is formed in a bottomed cylindrical shape and includes a side surface portion 15 and a bottom surface portion 16.

[0011] The side surface portion 15 is formed in a cylindrical shape and is arranged along the side surface of the cylinder. The bottom surface portion 16 is formed in a disk shape with irregularities and is arranged along one bottom surface of the cylinder. The edge of the bottom surface portion 16 is connected to one end of the side surface portion 15 and is integrally formed with the side surface portion 15. An opening 17 is formed in the positive electrode can 11. The opening 17 is formed at a position corresponding to the other bottom surface of the cylinder in the side surface portion 15. The internal space 18 formed inside the positive electrode can 11 is connected to the outside of the positive electrode can 11 through the opening 17. A positive electrode terminal portion 19 is formed at the center of the bottom surface portion 16. The bottom surface portion 16 is formed such that the positive electrode terminal portion 19 protrudes from the inside to the outside of the positive electrode can 11.

[0012] The negative electrode terminal plate 12 is formed of a conductor exemplified by metal and is generally formed in a disk shape. The negative electrode terminal plate 12 is arranged in the opening 17 along the other bottom surface of the cylinder.

[0013] The positive electrode 3 contains electrolytic manganese dioxide (MnO2), graphite (C), an aqueous potassium hydroxide solution, and a binder. Electrolytic manganese dioxide (MnO2) is the positive electrode active material. The binder contains, for example, a polymer compound. The positive electrode 3 is formed from powders of electrolytic manganese dioxide (MnO2) and graphite (C) bonded together via the binder to form a solid. The positive electrode 3 is cylindrical. A negative electrode filling hole (21) is formed inside the positive electrode 3, penetrating it. The positive electrode 3 is positioned in the internal space (18) such that its outer peripheral surface faces the side portion (15) of the positive electrode can (11). The positive electrode 3 is in close contact with the side portion (15) of the positive electrode can (11) and is electrically in contact with the positive electrode can (11).

[0014] The negative electrode 5 contains an aqueous potassium hydroxide solution, a gelling agent, and zinc powder. Examples of gelling agents include polyacrylic acid, polyacrylate salts, polyethylene glycol PEG, polyethylene oxide PEO, and carboxymethylcellulose CMC. Examples of polyacrylate salts include sodium polyacrylate and potassium polyacrylate. The zinc powder is formed from metallic zinc. The zinc powder may be substituted with other negative electrode active materials. Examples of other negative electrode active materials include zinc alloy powder formed from a zinc alloy containing zinc. The negative electrode 5 is formed in a gel-like state. The negative electrode 5 is placed in the negative electrode filling hole 21 of the positive electrode 3 within the internal space 18.

[0015] The current collector rod 6 is formed from a conductor, exemplified by metal, and is shaped like a rod. The current collector rod 6 is positioned in the internal space 18 along the central axis 22 of the cylinder along which the side portion 15 of the positive electrode can 11 is aligned, is embedded in the negative electrode 5, and is in electrical contact with the negative electrode 5.

[0016] The separator 7 is formed from a nonwoven fabric made of insulating fibers and is formed from a flexible sheet. Examples of insulating fibers include vinylon and pulp. The separator 7 is formed in the shape of a bottomed cylinder and comprises a side portion 25 and a bottom portion 26. The side portion 25 is formed in a tubular shape and runs along the side of the cylinder. The bottom portion 26 is formed in a circular sheet shape and runs along one bottom surface of the cylinder. The periphery of the bottom portion 26 is connected to one end of the side portion 25 so that no gap is formed between the side portion 25 and the bottom portion 26. An opening is formed at the separator open end 27 on the opposite side of the side portion 25 from the end connected to the bottom portion 26, allowing communication between the inside and outside of the separator 7. The separator 7 is positioned in the internal space 18 such that its side portion 25 is positioned between the positive electrode 3 and the negative electrode 5, and its bottom portion 26 is positioned between the negative electrode 5 and the bottom portion 16 of the positive electrode can 11. The negative electrode 5 is separated from the positive electrode 3 by the side portion 25 and is electrically insulated from the positive electrode 3. The negative electrode 5 is further separated from the bottom portion 16 of the positive electrode can 11 by the bottom portion 26 and is electrically insulated from the positive electrode can 11.

[0017] Battery 1 further comprises an electrolyte (not shown). The electrolyte is formed from an aqueous potassium hydroxide solution containing potassium hydroxide (KOH). The electrolyte is placed in the internal space 18 and permeates the positive electrode 3 and the separator 7, and the positive electrode 3 and the negative electrode 5 are immersed in the electrolyte.

[0018] Figure 2 is an enlarged cross-sectional view showing a part of the battery 1 of Embodiment 1. The sealing gasket 14 is formed from an insulator, exemplified by nylon, and is flexible. The sealing gasket 14 comprises a gasket boss portion 31, a gasket flange portion 32, and a gasket peripheral portion 33. The gasket boss portion 31 is formed in a tubular shape. The gasket flange portion 32 is generally formed in a disc shape with an opening in the center. The gasket flange portion 32 is integrally formed with the gasket boss portion 31 such that the gasket boss portion 31 penetrates the opening of the gasket flange portion 32, and protrudes outward from the outer peripheral surface of the gasket boss portion 31.

[0019] A separator-facing surface 34 is formed on the gasket flange portion 32. The separator-facing surface 34 is formed so as to be concave near the gasket boss portion 31 and generally follows the conical surface 35, which is the side surface of a cone with its apex positioned on the central axis 22. The gasket peripheral portion 33 is generally formed in a cylindrical shape. The gasket peripheral portion 33 is integrally formed with the gasket flange portion 32 such that the outer edge of the gasket flange portion 32 is adjacent to one end of the gasket peripheral portion 33.

[0020] The sealing gasket 14 is positioned in the opening 17 such that the separator-facing surface 34 of the gasket flange portion 32 faces the separator 7. The current collector rod 6 passes through the gasket boss portion 31. The sealing gasket 14 is fixed to the current collector rod 6 by the current collector rod 6 passing through the gasket boss portion 31. The peripheral portion 33 of the gasket is elastically deformed, sandwiched between the periphery of the negative electrode terminal plate 12 and the side portion 15 of the positive electrode can 11. The negative electrode terminal plate 12 is fixed to the positive electrode can 11 in a state where the negative electrode terminal plate 12 does not electrically contact the positive electrode can 11, because the peripheral portion 33 of the gasket is sandwiched between the periphery of the negative electrode terminal plate 12 and the side portion 15 of the positive electrode can 11. The gap formed between the negative electrode terminal plate 12 and the positive electrode can 11 is sealed by the gasket peripheral portion 33, which is sandwiched between the peripheral portion of the negative electrode terminal plate 12 and the side portion 15 of the positive electrode can 11. The internal space 18 is sealed from the outside of the positive electrode can 11 because the gap formed between the negative electrode terminal plate 12 and the positive electrode can 11 is sealed.

[0021] A beading portion 36 and a curled portion 37 are formed on the side portion 15 of the positive electrode can 11. The beading portion 36 is formed near the opening side end 38 of the side portion 15 on the side where the opening 17 is formed. The beading portion 36 is formed to protrude from the inner surface of the side portion 15 toward the inside of the positive electrode can 11, that is, the inner diameter of the portion of the side portion 15 where the beading portion 36 is formed is smaller than the inner diameter of the other portions. Because the beading portion 36 is formed on the side portion 15 of the battery 1, the positive electrode 3 can be prevented from coming out of the positive electrode can 11 through the opening 17.

[0022] The beading portion 36 is further in contact with the lower end of the gasket peripheral portion 33 of the sealing gasket 14 on the side of the bottom portion 16 of the positive electrode can 11. The sealing gasket 14 is further fixed to the positive electrode can 11 by the contact of the gasket peripheral portion 33 with the beading portion 36, so as not to move toward the bottom portion 16.

[0023] The curled portion 37 is formed between the beading portion 36 and the opening side end 38. The curled portion 37 is formed such that the inner diameter of the side portion 15 decreases as it approaches the opening side end 38. The curled portion 37 is further in contact with the upper end of the gasket peripheral portion 33 on the side of the positive electrode can 11 that is farther away from the bottom portion 16. The sealing gasket 14 is fixed to the positive electrode can 11 by the contact of the gasket peripheral portion 33 with the curled portion 37, so that the sealing gasket 14 does not come off the positive electrode can 11.

[0024] Figure 3 is a bottom view showing the sealing gasket 14 of the battery 1 of Embodiment 1. The gasket flange portion 32 of the sealing gasket 14 has eight radial protrusions 41 that project from the separator-facing surface 34. The eight radial protrusions 41 are arranged at equal intervals along a circle 42 surrounding the gasket boss portion 31. One of the eight radial protrusions 41, a radial protrusion 43, is formed in a generally triangular pyramidal shape. The radial protrusion 43 is formed such that the boss-facing surface 44 corresponding to one face of the triangular pyramid faces the gasket boss portion 31. The radial protrusion 43 further has a first inclined surface 45 and a second inclined surface 46 corresponding to the other two faces of the triangular pyramid. The radial protrusion 43 is formed such that the side 47 adjacent to the first inclined surface 45 and the second inclined surface 46 is contained in a plane 48 containing the central axis 22.

[0025] As shown in Figure 4, the radial projections 43 are formed in a V-shape, such that the cross-sectional shape of the radial projections 43 intersects with a plane 49 that is perpendicular to plane 48, which is a plane parallel to the central axis 22, and has a triangular cross-sectional shape. Figure 4 shows the cross-section along line AA in Figure 3 and is a cross-sectional view showing the radial projections 43. That is, the radial projections 43 are formed such that the width of the radial projections 43 in the circumferential direction 50 decreases as it moves away from the conical surface 35. The circumferential direction 50 is perpendicular to plane 48, that is, it is approximately parallel to the tangent line that touches the portion of the circle 42 that intersects with the radial projections 43.

[0026] The radial projections 43 are formed such that, as shown in Figure 3, the width of the radial projections 43 in the circumferential direction 50 decreases as it moves away from the gasket boss portion 31. Furthermore, as shown in Figure 2, the radial projections 43 are formed such that the height of the radial projections 43 relative to the conical surface 35 decreases as it moves away from the gasket boss portion 31. That is, the edge 47 is inclined with respect to the conical surface 35 such that the distance between the end of the edge 47 on the gasket peripheral portion 33 side and the conical surface 35 is smaller than the distance between the end of the edge 47 on the gasket boss portion 31 side and the conical surface 35. In other words, the radial projections 43 are pointed toward the gasket peripheral portion 33. Each of the seven radial projections among the eight radial projections 41 that are different from radial projection 43 is formed similarly to radial projection 43.

[0027] Figure 5 is a perspective view showing the side portion 25 of the separator 7. The separator open end portion 51 of the side portion 25 of the separator 7, near the separator open end 27, tapers along the separator-facing surface 34 of the sealing gasket 14, so that the diameter of the side portion 25 becomes smaller as it approaches the separator open end 27.

[0028] Figure 6 is a perspective view showing the separator open end portion 51 and the eight radial protrusions 41 of the separator 7. Due to the tapering of the separator open end portion 51, wrinkles form on the separator open end portion 51, creating irregularities 52. These irregularities 52 fit into the eight radial protrusions 41 of the sealing gasket 14.

[0029] The gap 53 formed between the separator 7 and the sealing gasket 14 is narrowed as the irregularities 52 fit into the eight radial projections 41, as shown in Figure 7. Figure 7 is a cross-sectional view showing the gap 53 formed between the separator 7 and the sealing gasket 14. Because the gap 53 is narrowed, the battery 1 can prevent a portion of the negative electrode 5 from entering the space on the positive electrode 3 side of the internal space 18 through the gap 53, thereby preventing an internal short circuit from occurring where the positive electrode 3 and the negative electrode 5 make electrical contact.

[0030] [Battery manufacturing method] In the battery manufacturing method for producing battery 1, a positive electrode 3 is prepared, and a positive electrode can is prepared in which the beading portion 36 and the curled portion 37 have not yet been formed. The positive electrode 3 is inserted into the positive electrode can through the opening 17. The positive electrode can is processed so that the beading portion 36 is formed after the positive electrode 3 has been inserted into the positive electrode can. The beading portion 36 prevents the positive electrode 3 from coming out of the positive electrode can through the opening 17.

[0031] In the battery manufacturing method, a separator 7, electrolyte, and negative electrode 5 are further prepared. After the positive electrode 3 is inserted into the positive electrode can, the separator 7 is inserted into the negative electrode filling hole 21 of the positive electrode 3 through the opening 17. The electrolyte is injected into the negative electrode filling hole 21 of the positive electrode 3 through the opening 17 after the separator 7 has been inserted inside the positive electrode 3. As the electrolyte is injected into the negative electrode filling hole 21 of the positive electrode 3, the electrolyte soaks into the separator 7 and then into the positive electrode 3. The negative electrode 5 is injected into the inside of the separator 7 in a predetermined amount after the electrolyte has soaked into the separator 7 and the positive electrode 3.

[0032] In the battery manufacturing method, a current collector rod 6, a negative electrode terminal plate 12, and a sealing gasket 14 are further prepared. The gasket boss portion 31 is elastically deformed when the current collector rod 6 passes through it, and adheres tightly to the current collector rod 6 by elastic force. The sealing gasket 14 is fixed to the current collector rod 6 by the gasket boss portion 31 adhering tightly to the current collector rod 6. The current collector rod 6, the negative electrode terminal plate 12, and the sealing gasket 14 are assembled and fixed to each other so that the current collector rod 6 contacts the negative electrode terminal plate 12, and the outside of the periphery of the negative electrode terminal plate 12 is covered by the gasket peripheral portion 33 of the sealing gasket 14, thereby creating a sealing body. After the negative electrode 5 is injected, the sealing body is attached to the positive electrode can so that the current collector rod 6 is embedded in the negative electrode 5, and one end of the gasket peripheral portion 33 of the sealing gasket 14 contacts the beading portion 36.

[0033] The separator open end portion 51 of the separator 7 comes into contact with the eight radial projections 41 of the sealing gasket 14 while the sealing body is being attached to the positive electrode can, and is subjected to multiple creases. Further, while the sealing body is being attached to the positive electrode can, the separator open end portion 51 of the separator 7 narrows so that the separator open end 27 approaches the gasket boss portion 31 of the sealing gasket 14, and is bent and wrinkled along its multiple creases.

[0034] The sealing body is positioned appropriately relative to the positive electrode can by the gasket peripheral portion 33 of the sealing gasket 14 contacting the beading portion 36. The separator open end portion 51 of the separator 7 is further tapered when the sealing body is positioned appropriately, forming irregularities 52 along the separator-facing surface 34 of the sealing gasket 14. The irregularities 52 fit into the eight radial projections 41 of the sealing gasket 14 when the separator open end portion 51 is aligned with the separator-facing surface 34 of the sealing gasket 14.

[0035] The positive electrode can is crimped after the sealing body is positioned appropriately, forming a curled portion 37 on the positive electrode can 11. The sealing body is fixed to the positive electrode can 11 by the formation of the curled portion 37 on the positive electrode can 11, so that the sealing body does not come off the positive electrode can 11, and the battery 1 is manufactured.

[0036] Battery 1 discharges so that electricity flows to the load when the negative terminal plate 12 and the positive terminal portion 19 of the positive terminal can 11 are connected to a load. When vibration or shock is applied to Battery 1, a portion of the negative electrode 5 may enter the space in the internal space 18 where the positive electrode 3 is located through the gap 53, causing an internal short circuit where the negative electrode 5 makes electrical contact with the positive electrode 3. By making the gap 53 small, Battery 1 can prevent a portion of the negative electrode 5 from entering the space in the internal space 18 where the positive electrode 3 is located through the gap 53, thereby preventing an internal short circuit from occurring.

[0037] In the battery 1 of Embodiment 1 described above, each of the eight radial protrusions 41 is angular at the edge 47, but each of the eight radial protrusions 41 does not necessarily have to be angular at the edge 47. The modified battery, as shown in Figure 8, is the same as the battery 1 of Embodiment 1 described above, but with the sealing gasket 14 replaced by another sealing gasket 61. Figure 8 is a cross-sectional view showing the radial protrusions 62 of the sealing gasket 61 of the modified battery. The parts of the sealing gasket 61 of the modified battery that differ from the sealing gasket 61 are the same as the parts that differ from the sealing gasket 14 of the battery 1 of Embodiment 1 described above. The sealing gasket 61 is the same as the sealing gasket 14 described above, but with each of the eight radial protrusions 41 replaced by another radial protrusion 62, and the other parts are the same as the sealing gasket 14 described above.

[0038] The radial projection 62 is formed by chamfering the portion corresponding to the side 47 of the radial projection 43 described above, and a U-shaped curved surface 63 is formed. The U-shaped curved surface 63 is formed between the first inclined surface 45 and the second inclined surface 46, and is gently connected to the first inclined surface 45 and the second inclined surface 46, and is gently curved. In this case as well, the radial projection 62 is formed such that the width of the radial projection 62 in the circumferential direction 50 decreases as it moves away from the conical surface 35. The modified battery, like the battery 1 of the embodiment described above, can reduce the gap formed between the separator 7 and the sealing gasket 61, and can prevent internal short circuits from occurring. Furthermore, because the sealing gasket 61 has a U-shaped curved surface 63 formed on each of the eight radial projections, it can be easily manufactured by injection molding compared to the sealing gasket 14 described above. For this reason, the modified battery can reduce manufacturing costs compared to the battery 1 of the embodiment described above. [Examples]

[0039] In addition, although the radial projections 43 of the battery 1 in Example 1 described above are formed to have a triangular cross-sectional shape, they may be formed to have a polygonal cross-sectional shape other than a triangle. The battery in Example 2, as shown in Figure 9, is the same as the battery in Example 1 described above, but with the sealing gasket 14 replaced by another sealing gasket 65. The parts of the sealing gasket 65 in the battery in Example 2 that differ from the sealing gasket 14 in the battery 1 in Example 1 described above are the same as the parts that differ from the sealing gasket 14 in the battery 1 in Example 1 described above. Figure 9 is a cross-sectional view showing the radial projections 66 of the sealing gasket 65 of the battery in Example 2. In the sealing gasket 65, each of the eight radial projections 41 of the sealing gasket 14 described above is replaced by another radial projection 66, and the other parts are the same as the sealing gasket 14 described above. The radial projections 66 are formed so that the cross-sectional shape where the radial projections 66 intersect the plane 49 is a pentagon. The radial projections 66 are further formed such that the width of the radial projections 66 in the circumferential direction 50 decreases as it moves away from the conical surface 35. The battery of Example 2, like the battery of Example 1 described above, can also reduce the gap formed between the separator 7 and the sealing gasket 65, thereby preventing internal short circuits from occurring. [Examples]

[0040] In the battery 1 of Example 1 described above, eight radial protrusions 41 are formed on the sealing gasket 14, but a different number of radial protrusions may be formed. The battery of Example 3, as shown in Figure 10, is the same as the battery 1 of Example 1 described above, but with the sealing gasket 14 replaced by another sealing gasket 71. The parts of the sealing gasket 71 of the battery of Example 3 that differ from the sealing gasket 14 of the battery 1 of Example 1 described above are the same as the parts that differ from the sealing gasket 14 of the battery 1 of Example 1 described above. Figure 10 is a bottom view showing the sealing gasket 71 of the battery of Example 3. The sealing gasket 71 is the same as the sealing gasket 14 described above, but with the eight radial protrusions 41 replaced by other 16 radial protrusions 72, and the other parts are the same as the sealing gasket 14 described above. The 16 radial protrusions 72 are arranged at equal intervals along the circle 42. Each of the 16 radial protrusions 72 is formed in the same way as the radial protrusions 43 described above. Similar to battery 1 in the previously described embodiment, the battery of Embodiment 3 also allows for a smaller gap to be formed between the separator 7 and the sealing gasket 71, thereby preventing internal short circuits. [Examples]

[0041] The battery of Example 4, as shown in Figure 11, is the same as the battery 1 of Example 1 described above, but with the sealing gasket 14 replaced by another sealing gasket 75. The parts of the sealing gasket 75 of the battery of Example 4 that differ from the sealing gasket 14 of the battery 1 of Example 1 described above are the same as the parts that differ from the sealing gasket 14 of the battery 1 of Example 1 described above. Figure 11 is a bottom view showing the sealing gasket 75 of the battery of Example 4. The sealing gasket 75 is the same as the sealing gasket 14 described above, but with the eight radial protrusions 41 replaced by other eight radial protrusions 76. Each of the eight radial protrusions 76 is formed in a roughly rectangular parallelepiped shape. Therefore, the radial protrusions 77 are formed such that the height of the radial protrusion 77 relative to the conical surface 35 does not change as it moves away from the gasket boss portion 31.

[0042] Figure 12 is a bottom view showing the sealing gasket 75 of the battery in Example 4. The eight radial protrusions 76 are arranged at equal intervals along the circle 42, similar to the eight radial protrusions 41 of the battery 1 in Example 1 described above. The radial protrusions 77 are formed such that the width of the radial protrusions 77 in the circumferential direction 50 remains constant and does not change as it moves away from the gasket boss portion 31.

[0043] Figure 13 shows a cross-sectional view of the BB line in Figure 12, and is a cross-sectional view showing the radial projections 77 of the battery in Example 4. The radial projections 77 are formed such that the shape of the cross-section where the radial projections 77 intersect the plane 49 is a square (rectangle). That is, the radial projections 77 are formed such that the width of the radial projections 43 in the circumferential direction 50 remains constant and does not change as it moves away from the conical surface 35. The battery in Example 4, like the battery in Example 1 described above, can reduce the gap formed between the separator 7 and the sealing gasket 75, thereby preventing internal short circuits. [Examples]

[0044] The battery of Example 5 is obtained by replacing the eight radial protrusions 41 of the sealing gasket 14 of the battery 1 of Example 1 described above with other eight radial protrusions. The differences between the eight radial protrusions of the battery of Example 5 and those of the battery 1 described above are the same as the differences between the eight radial protrusions 41 of the battery 1 of Example 1 described above. The eight radial protrusions of the battery of Example 5 are arranged at equal intervals along the circle 42, similar to the eight radial protrusions 41 of the battery 1 of Example 1 described above.

[0045] Each of the eight radial protrusions of the battery in Example 5 is formed in a generally triangular prism shape. The radial protrusions are formed such that one surface corresponding to the base of the triangular prism of the radial protrusion faces the gasket boss portion 31, and one surface corresponding to the side of the triangular prism of the radial protrusion faces the gasket flange portion 32. That is, as shown in Figure 11, the radial protrusions of the battery in Example 5 are formed such that their height relative to the conical surface 35 remains constant and does not change as they move away from the gasket boss portion 31. Furthermore, as shown in Figure 12, the radial protrusions of the battery in Example 5 are formed such that their width in the circumferential direction 50 remains constant and does not change as they move away from the gasket boss portion 31. Furthermore, as shown in Figure 4, the radial protrusions of the battery in Example 5 are formed such that their width in the circumferential direction 50 decreases as they move away from the conical surface 35. Similar to battery 1 in the previously described embodiment, the battery of Example 5 also allows for a smaller gap to be formed between the separator 7 and the sealing gasket, thereby preventing internal short circuits. [Examples]

[0046] The battery of Example 6 is obtained by replacing the eight radial protrusions 41 of the sealing gasket 14 of the battery 1 of Example 1 described above with eight additional radial protrusions. The differences between the eight radial protrusions of the battery of Example 6 and those of the battery 1 described above are the same as the differences between the eight radial protrusions 41 of the battery 1 of Example 1 described above. The eight radial protrusions of the battery of Example 6 are arranged at equal intervals along the circle 42, similar to the eight radial protrusions 41 of the battery 1 of Example 1 described above.

[0047] Each of the eight radial protrusions of the battery in Example 6 is formed in a generally square pyramidal shape. The radial protrusions are formed such that the surface corresponding to the base of the square pyramidal protrusion faces the gasket boss portion 31, and the surface corresponding to one side of the square pyramidal protrusion faces the gasket flange portion 32. That is, as shown in Figure 2, the radial protrusions of the battery in Example 6 are formed such that the height relative to the conical surface 35 decreases as it moves away from the gasket boss portion 31. Furthermore, as shown in Figure 3, the radial protrusions of the battery in Example 6 are formed such that the width in the circumferential direction 50 decreases as it moves away from the gasket boss portion 31. Furthermore, as shown in Figure 13, the radial protrusions of the battery in Example 6 are formed such that the width in the circumferential direction 50 remains constant and does not change as it moves away from the conical surface 35. Similar to battery 1 in the previously described embodiment, the battery of embodiment 6 also allows for a smaller gap to be formed between the separator 7 and the sealing gasket, thereby preventing internal short circuits.

[0048] [Comparative Example 1] As shown in Figure 14, the battery 100 of Comparative Example 1 is modified in which the sealing gasket 14 of the battery 1 of Example 1 described above is replaced with another sealing gasket 101. Figure 14 is a cross-sectional view showing the battery 100 of Comparative Example 1. The parts of the battery of Comparative Example 1 that differ from the sealing gasket 101 are the same as the parts of the battery 1 of Example 1 described above that differ from the sealing gasket 14. As shown in Figure 15, the sealing gasket 101 is modified in which the gasket flange portion 32 of the sealing gasket 14 described above is replaced with another gasket flange portion 102 that does not have eight radial protrusions 41 formed thereon. Figure 15 is a bottom view showing the sealing gasket 101 of the battery 100 of Comparative Example 1. The parts of the sealing gasket 101 that differ from the gasket flange portion 102 are the same as the parts of the sealing gasket 14 described above that differ from the gasket flange portion 32. The gasket flange portion 102 has a separator-facing surface 34 that follows the conical surface 35, similar to the gasket flange portion 32 described above.

[0049] The separator open end portion 51 of the separator 7 is tapered because the separator facing surface 34 follows the conical surface 35. In the battery 100 of Comparative Example 1, the tapered separator open end portion 51 prevents a portion of the negative electrode 5 from flowing out to the positive electrode 3 side through the opening of the separator 7. In the battery 100 of Comparative Example 1, the tapered separator open end portion 51 of the separator 7 can cause wrinkles to form on the separator open end portion 51 during manufacturing, creating an uneven surface and potentially forming a large gap between the separator 7 and the sealing gasket 101. In the battery 100 of Comparative Example 1, a portion of the negative electrode 5 may flow out to the positive electrode 3 side through this large gap, potentially causing an internal short circuit. Compared to the battery 100 of Comparative Example 1, the batteries of Examples 1 to 6 described above can reduce the gap 53, preventing a portion of the negative electrode 5 from entering the positive electrode 3 side of the separator 7 through the gap 53, and thus preventing an internal short circuit.

[0050] [Comparative Example 2] As shown in Figure 16, the battery 200 of Comparative Example 2 is modified in which the sealing gasket 14 of the battery 1 of Example 1 described above is replaced with another sealing gasket 201. Figure 16 is a cross-sectional view showing the battery 200 of Comparative Example 2. The parts of the battery 200 of Comparative Example 2 that differ from the sealing gasket 201 are the same as the parts that differ from the sealing gasket 14 of the battery 1 of Example 1 described above. The sealing gasket 201 is modified in which the gasket flange portion 32 of the sealing gasket 14 described above is replaced with another gasket flange portion 202. The parts of the sealing gasket 201 that differ from the gasket flange portion 202 are the same as the parts that differ from the gasket flange portion 32 of the sealing gasket 14 described above.

[0051] The gasket flange portion 202 is equipped with a clamping portion 203. When the sealing body is fixed to the positive electrode can 11, the clamping portion 203 clamps the separator open end portion 51 of the separator 7 by deforming the sealing gasket 201. The separator 7 is fixed to the sealing gasket 201 by the clamping portion 203 at the separator open end portion 51, and is fixed to the positive electrode can 11 via the sealing gasket 201.

[0052] In Comparative Example 2, the open end portion 51 of the separator is clamped by the clamping portion 203, so no gap is formed between the open end 27 of the separator 7 and the sealing gasket 201. In Comparative Example 2, because no gap is formed between the open end 27 of the separator and the sealing gasket 201, it is possible to prevent a part of the negative electrode 5 from entering the space in the internal space 18 where the positive electrode 3 is located through the opening of the separator 7. In Comparative Example 2, because the open end portion 51 of the separator is clamped by the clamping portion 203, when an impact is applied, the gel-like negative electrode 5 moves, which can cause the separator 7 to rupture and a hole to form in the separator 7. In Comparative Example 2, when the separator 7 ruptures, a part of the negative electrode 5 may enter the outside of the separator 7 through the hole in the separator 7, which can cause an internal short circuit. In the batteries of Examples 1 to 6 described above, the separator 7 is not fixed to the sealing gasket at the separator open end portion 51, which prevents the separator 7 from tearing and thus prevents internal short circuits from occurring compared to the battery 200 of Comparative Example 2.

[0053] [Evaluation tests of batteries in Examples 1-6] To verify the effectiveness of the batteries in Examples 1-6, multiple battery samples were fabricated for each of the multiple battery examples. Table 1 shows the shape information for the multiple battery examples. [Table 1] Among the multiple shape information entries, the shape information corresponding to a particular battery indicates the shape of the sealing gasket provided on that battery. Each of the multiple shape information entries shows the gasket shape, the cross-sectional shape of the protrusions, the width and height of the protrusions, and the number of protrusions.

[0054] The gasket shape indicates the shape of the battery's sealing gasket and is one of the following: "separator folded," "separator clamped," or "radial protrusions." When the gasket shape in the shape information for a particular battery indicates "separator folded," it indicates that the sealing gasket of that battery does not have radial protrusions. When the gasket shape in the shape information for a particular battery indicates "separator clamped," it indicates that the sealing gasket of that battery clamps the separator open end portion 51 of the separator 7. When the gasket shape in the shape information for a particular battery indicates "radial protrusions," it indicates that the sealing gasket of that battery has multiple radial protrusions.

[0055] The projection cross-sectional shape indicates the shape of the cross-section where each of the multiple radial projections formed on the battery's sealing gasket intersects the plane 49, and is shown as either "-", "square", "V-shape", or "polygon". When the projection cross-sectional shape of the shape information corresponding to a battery shows "-", it indicates that no radial projections are formed on the sealing gasket of that battery. When the projection cross-sectional shape of the shape information corresponding to a battery shows "square", it indicates that the cross-sectional shape of the radial projections of that battery is rectangular, as shown in Figure 13, and that the width in the circumferential direction 50 remains constant and does not change as it moves away from the conical surface 35. When the projection cross-sectional shape of the shape information corresponding to a battery shows "V-shape", it indicates that the cross-sectional shape of the radial projections of that battery is V-shaped, as shown in Figure 4, and that the width of the radial projections in the circumferential direction 50 decreases as it moves away from the conical surface 35. When the shape information for a particular battery indicates that the cross-sectional shape of the protrusions is "polygonal," it indicates that the cross-sectional shape of the radial protrusions of that battery is pentagonal, as shown in Figure 9, and that the width in the circumferential direction 50 decreases as it moves away from the conical surface 35.

[0056] The projection width and height refer to the height and width in the circumferential direction 50 of each of the multiple radial projections formed on the battery's sealing gasket, and indicate one of the following: "-", "thicker on the boss side, thinner on the circumferential side", or "constant width and height". When the projection width and height of the shape information corresponding to a battery indicates "-", it indicates that no radial projections are formed on the sealing gasket of that battery. When the projection width and height of the shape information corresponding to a battery indicates "thicker on the boss side, thinner on the circumferential side", it indicates that the height and width of the radial projections on the sealing gasket of that battery decrease as they move away from the gasket boss portion 31, as shown in Figures 2 and 3. When the projection width and height of the shape information corresponding to a battery indicates "constant width and height", it indicates that the height and width of the radial projections on the sealing gasket of that battery remain constant and do not change as they move away from the gasket boss portion 31, as shown in Figures 11 and 12.

[0057] The number of protrusions indicates the number of radial protrusions formed on the battery's sealing gasket, and is shown as either "-", "8", or "16". When the number of protrusions in the shape information for a particular battery is "-", it indicates that no radial protrusions are formed on the sealing gasket of that battery. When the number of protrusions in the shape information for a particular battery is "8", it indicates that there are 8 radial protrusions formed on the sealing gasket of that battery. When the number of protrusions in the shape information for a particular battery is "16", it indicates that there are 16 radial protrusions formed on the sealing gasket of that battery.

[0058] Multiple shape details differ from one another. That is, the shapes of the sealing gaskets in the multiple battery examples differ from one another. All battery samples are manufactured similarly to each other, except for the difference in sealing gasket shape. For example, all battery samples are manufactured so that their size is equal to that of a standard AA battery (LR6).

[0059] The multiple battery examples include the battery of Comparative Example 1, the battery of Comparative Example 2, the battery of Example 1, the battery of Example 2, the battery of Example 3, the battery of Example 4, the battery of Example 5, and the battery of Example 6. The sealing gasket of each of the multiple battery samples of the battery of Comparative Example 1 does not have multiple radial protrusions formed on it. That is, each of the multiple battery samples of the battery of Comparative Example 1 is formed from the battery of Comparative Example 1.

[0060] Each of the multiple battery samples of Comparative Example 2 has a sealing gasket that sandwiches the separator open end portion 51 of the separator 7. In other words, each of the multiple battery samples of Comparative Example 2 is formed from the battery of Comparative Example 2.

[0061] Each of the battery samples of the battery in Example 1 has a sealing gasket with a V-shaped cross-section of radial protrusions, where the height and width of the radial protrusions decrease as they move away from the gasket boss portion 31, and there are eight radial protrusions. In other words, each of the battery samples of the battery in Example 1 is formed from the battery of Example 1.

[0062] Each of the battery samples of the battery in Example 2 has a sealing gasket with radial projections that have a pentagonal cross-sectional shape, and the height and width of the radial projections decrease as they move away from the gasket boss portion 31, with a total of 8 radial projections. In other words, each of the battery samples of the battery in Example 2 is formed from the battery of Example 2.

[0063] Each of the battery samples of the battery in Example 3 has a sealing gasket with a V-shaped cross-section of radial projections, where the height and width of the radial projections decrease as they move away from the gasket boss portion 31, and there are 16 radial projections. In other words, each of the battery samples of the battery in Example 3 is formed from the battery of Example 3.

[0064] Each of the battery samples of the battery in Example 4 has a sealing gasket in which the cross-sectional shape of the radial projections is rectangular, the height and width of the radial projections remain constant and do not change as they move away from the gasket boss portion 31, and there are eight radial projections. In other words, each of the battery samples of the battery in Example 4 is formed from the battery of Example 4.

[0065] Each of the battery samples of the battery in Example 5 has a sealing gasket with a V-shaped cross-section of radial projections, where the height and width of the radial projections remain constant and do not change as they move away from the gasket boss portion 31, and the number of radial projections is 8. In other words, each of the battery samples of the battery in Example 5 is formed from the battery of Example 5.

[0066] Each of the battery samples of the battery in Example 6 has a sealing gasket with a rectangular cross-sectional shape of radial projections, where the height and width of the radial projections decrease as they move away from the gasket boss portion 31, and there are eight radial projections. In other words, each of the battery samples of the battery in Example 6 is formed from the battery of Example 6.

[0067] Table 1 further shows multiple transport-vibration evaluation results and multiple drop evaluation results corresponding to multiple battery examples. The transport-vibration evaluation result corresponding to a particular battery among the multiple transport-vibration evaluation results is derived by performing transport-vibration tests on multiple battery samples of that battery. The transport-vibration tests conform to the tests specified in JIS standard JIS C8514 B-2. In the transport-vibration test, a predetermined vibration is applied to the battery sample, and the open-circuit voltage before vibration application and the open-circuit voltage after vibration application are measured. The open-circuit voltage before vibration application indicates the open-circuit voltage OCV of the battery sample before vibration is applied. The open-circuit voltage after vibration application indicates the open-circuit voltage OCV of the battery sample after vibration is applied. The transport-vibration evaluation result shows the number of battery samples for which the voltage drop calculated by subtracting the open-circuit voltage after vibration application from the open-circuit voltage before vibration application is 1mV or more when transport-vibration tests are performed on 40 battery samples of that battery. Multiple transport-vibration evaluation results indicate that batteries with smaller transport-vibration evaluation values ​​have a lower risk of internal short circuits and better vibration resistance.

[0068] Among the multiple transport-vibration evaluation results, the transport-vibration evaluation result corresponding to the battery of Comparative Example 1 shows 5 / 40. The transport-vibration evaluation result corresponding to the battery of Comparative Example 2 shows 0 / 40. The transport-vibration evaluation result corresponding to the battery of Example 1 shows 0 / 40. The transport-vibration evaluation result corresponding to the battery of Example 2 shows 0 / 40. The transport-vibration evaluation result corresponding to the battery of Example 3 shows 0 / 40. The transport-vibration evaluation result corresponding to the battery of Example 4 shows 4 / 40. The transport-vibration evaluation result corresponding to the battery of Example 5 shows 3 / 40. The transport-vibration evaluation result corresponding to the battery of Example 6 shows 2 / 40.

[0069] Therefore, multiple transport-vibration evaluation results indicate that the batteries of Examples 1 to 6 have better vibration resistance than the battery of Comparative Example 1, and that the batteries of Examples 1 to 6 can suppress internal short circuits compared to the battery of Comparative Example 1. In other words, multiple transport-vibration evaluation results indicate that batteries with multiple radial protrusions have better vibration resistance than batteries without multiple radial protrusions.

[0070] Multiple transport-vibration evaluation results further indicate that even when vibration is applied to the battery of Comparative Example 2, no internal short circuit occurs in the battery of Comparative Example 2, and that a portion of the negative electrode 5 of the battery of Comparative Example 2 does not come into contact with the positive electrode 3. In other words, multiple transport-vibration evaluation results indicate that the battery in which the sealing gasket sandwiches the separator open end portion 51 of the separator 7 has good vibration resistance.

[0071] Multiple transport-vibration evaluation results further indicate that the vibration resistance of the battery in Example 1 is better than that of the battery in Example 6, and that the vibration resistance of the battery in Example 5 is better than that of the battery in Example 4. In other words, multiple transport-vibration evaluation results indicate that batteries with a V-shaped cross-section of radial protrusions have better vibration resistance compared to batteries with a square cross-section of radial protrusions.

[0072] Multiple transport-vibration evaluation results further indicate that the vibration resistance of the battery in Example 1 is better than that of the battery in Example 5, and that the vibration resistance of the battery in Example 6 is better than that of the battery in Example 4. In other words, multiple transport-vibration evaluation results indicate that batteries in which the height and width of the radial protrusions decrease as they move away from the gasket boss portion 31 have better vibration resistance compared to batteries in which the height and width of the radial protrusions are constant.

[0073] The drop evaluation result corresponding to a particular battery among multiple drop evaluation results is derived by performing a drop test on a battery sample of that battery. In the drop test, the battery sample is dropped five times from a height of 1m onto a concrete floor with the negative terminal plate 12 facing downwards, and the open-circuit voltage before dropping and the open-circuit voltage after dropping are measured. The open-circuit voltage before dropping represents the open-circuit voltage OCV of the battery sample before being dropped five times. The open-circuit voltage after dropping represents the open-circuit voltage OCV of the battery sample after being dropped five times. The drop evaluation result indicates the number of battery samples for which the voltage drop calculated by subtracting the open-circuit voltage after dropping from the open-circuit voltage before dropping is 1mV or more when a drop test is performed on 10 battery samples manufactured as that battery. Multiple drop evaluation results indicate that batteries corresponding to drop evaluation results with smaller values ​​have a lower risk of internal short circuits and better shock resistance.

[0074] Among the multiple drop evaluation results, the drop evaluation result corresponding to the battery of Comparative Example 1 shows 5 / 10. The drop evaluation result corresponding to the battery of Comparative Example 2 shows 4 / 10. The drop evaluation result corresponding to the battery of Example 1 shows 0 / 10. The drop evaluation result corresponding to the battery of Example 2 shows 0 / 10. The drop evaluation result corresponding to the battery of Example 3 shows 0 / 10. The drop evaluation result corresponding to the battery of Example 4 shows 3 / 10. The drop evaluation result corresponding to the battery of Example 5 shows 2 / 10. The drop evaluation result corresponding to the battery of Example 6 shows 1 / 10.

[0075] Therefore, multiple drop evaluation results indicate that the risk of internal short circuits occurring in the batteries of Examples 1 to 6 is lower than the risk of internal short circuits occurring in the batteries of Comparative Examples 1 to 2, indicating that the impact resistance of the batteries of Examples 1 to 6 is better than that of the batteries of Comparative Examples 1 to 2. In other words, multiple drop evaluation results indicate that batteries with multiple radial protrusions have better impact resistance than batteries without multiple radial protrusions. Furthermore, multiple drop evaluation results indicate that batteries with multiple radial protrusions have better impact resistance than batteries in which the separator open end portion 51 of the separator 7 is sandwiched between sealing gaskets.

[0076] Multiple drop evaluation results further indicate that when the battery of Comparative Example 2 is subjected to impact, an internal short circuit may occur in the battery of Comparative Example 2, and the separator 7 of the battery of Comparative Example 2 may rupture. In other words, multiple drop evaluation results indicate that, compared to batteries in which the sealing gasket sandwiches the separator open end portion 51 of the separator 7, the rupture of the separator 7 when the battery is subjected to impact can be suppressed.

[0077] Multiple drop evaluation results further indicate that the impact resistance of the battery in Example 1 is better than that of the battery in Example 6, and that the impact resistance of the battery in Example 5 is better than that of the battery in Example 4. In other words, multiple drop evaluation results indicate that batteries with a V-shaped cross-section of radial protrusions have better impact resistance compared to batteries with a square cross-section of radial protrusions.

[0078] Multiple drop evaluation results further indicate that the impact resistance of the battery in Example 1 is better than that of the battery in Example 5, and that the impact resistance of the battery in Example 6 is better than that of the battery in Example 4. In other words, multiple drop evaluation results indicate that batteries in which the height and width of the radial protrusions decrease as they move away from the gasket boss portion 31 have better impact resistance compared to batteries in which the height and width of the radial protrusions are constant.

[0079] [Effects of the battery in the embodiment] The batteries of Examples 1 to 6 comprise a positive electrode casing 11, a positive electrode 3, a negative electrode 5, a separator 7, a negative electrode terminal plate 12, a current collector rod 6, and sealing gaskets 14, 65, 71, and 75. The positive electrode 3 is located in an internal space 18 formed in the positive electrode casing 11. The negative electrode 5 is located in a negative electrode filling hole 21 formed in the positive electrode 3. The separator 7 is located between the negative electrode 5 and the positive electrode 3. The negative electrode terminal plate 12 is located in an opening 17 of the positive electrode casing 11. The current collector rod 6 is embedded in the negative electrode 5. The sealing gaskets 14, 65, 71, and 75 comprise a gasket boss portion 31, a gasket peripheral portion 33, and a gasket flange portion 32. The gasket boss portion 31 is fixed to the current collector rod 6. The gasket peripheral portion 33 seals the gap formed between the negative electrode terminal plate 12 and the positive electrode casing 11. The gasket flange portion 32 is formed between the gasket boss portion 31 and the gasket peripheral edge portion 33. On the separator-facing surface 34 of the gasket flange portion 32 that faces the separator 7, a plurality of radial protrusions 41, 72, and 76 are formed, arranged along the circle 42 surrounding the gasket boss portion 31.

[0080] In the batteries of Examples 1 to 6, the separator open end 27 of the separator 7 is shaped in such a way that it contacts multiple radial protrusions 41, 72, and 76 during battery assembly, forming a predetermined number of grooves 52. After the battery is assembled, the separator open end 27 is narrowed, forming the grooves 52, which then fit into the multiple radial protrusions 41, 72, and 76. In the batteries of Examples 1 to 6, the grooves 52 of the separator 7 fit into the multiple radial protrusions 41, 72, and 76, thereby reducing the gap 53 formed between the sealing gaskets 14, 65, 71, and 75 and the separator 7. In the batteries of Examples 1 to 6, the small gap 53 prevents a portion of the negative electrode 5 from entering the internal space 18 on the side where the positive electrode 3 is located through the gap 53, thus preventing an internal short circuit where the negative electrode 5 electrically contacts the positive electrode 3.

[0081] Furthermore, the radial protrusions 43, 62, and 66 of the batteries in Examples 1-3 and 6 are formed such that the width of the radial protrusions 43, 62, and 66 in the circumferential direction 50 decreases as they move away from the gasket boss portion 31. Compared to other batteries in Examples 1-3 and 6, where the width of the radial protrusions remains constant and does not change as they move away from the gasket boss portion 31, the gap 53 can be made smaller, and contact between a portion of the negative electrode 5 and the positive electrode 3 through the gap 53 can be suppressed.

[0082] Furthermore, the radial protrusions 43, 62, and 66 of the batteries in Examples 1-3 and 6 are formed such that the height of the radial protrusions 43, 62, and 66 relative to the separator-facing surface 34 decreases as they move away from the gasket boss portion 31. Compared to other batteries in Examples 1-3 and 6, where the height of the radial protrusions remains constant and does not change as they move away from the gasket boss portion 31, the batteries in Examples 1-3 and 6 can have a smaller gap 53, and can suppress contact between a portion of the negative electrode 5 and the positive electrode 3 through the gap 53.

[0083] Furthermore, the radial protrusions 43, 62, and 66 of the batteries in Examples 1-3 and 5 are formed such that their width in the circumferential direction 50 decreases as they move away from the separator-facing surface 34, that is, the cross-sectional shape of the radial protrusion 43 is V-shaped. Compared to other batteries in Examples 1-3 and 5, where the height of the radial protrusions remains constant and does not change as they move away from the gasket boss portion 31, the gap 53 can be made smaller, and contact between a portion of the negative electrode 5 and the positive electrode 3 through the gap 53 can be suppressed.

[0084] Incidentally, in the batteries of the previously described embodiments 1 to 3 and 6, both the height and width of the radial protrusions 43, 62, and 66 decrease as they move away from the gasket boss portion 31, and in the batteries of the previously described embodiments 4 to 5, both the height and width of the radial protrusion 77 remain constant as they move away from the gasket boss portion 31. However, either the height or width of the radial protrusion may decrease as it moves away from the gasket boss portion 31, while the other remains constant as it moves away from the gasket boss portion 31. For example, the radial protrusion is formed in the shape of a triangular prism with an isosceles triangle as its base. The radial protrusion is formed such that one of the two bases of the triangular prism faces the gasket flange portion 32, and one of the three sides of the triangular prism that includes the base of the isosceles triangle faces the gasket boss portion 31. Alternatively, the radial protrusion is formed in the shape of a triangular prism with a right triangle as its base. The radial projections are formed such that the surface corresponding to the side containing one adjacent side of the right triangle in the triangular prism faces the gasket boss portion 31, and the surface corresponding to the side containing the other adjacent side of the right triangle in the triangular prism faces the gasket flange portion 32. Even when radial projections are formed in such a triangular prism shape, the battery of this embodiment, like the battery 1 of the previously described embodiment, can reduce the gap formed between the sealing gasket and the separator, thereby preventing internal short circuits.

[0085] Incidentally, although the separator-facing surface 34 of the battery in the previously described embodiment is aligned with the conical surface 35, it does not have to be aligned with the conical surface 35; for example, it may be aligned with a plane. Even when the separator-facing surface 34 is not aligned with the conical surface 35, the battery of the embodiment can reduce the gap formed between the sealing gasket and the separator, similar to the battery in the previously described embodiment, thereby preventing internal short circuits.

[0086] Incidentally, although the battery in the embodiment described above is formed from an alkaline manganese dry cell, it may also be formed from other batteries in which the gel-like negative electrode may leak out through the gap formed between the sealing gasket and the separator. An example of such a battery is a zinc secondary battery. Even when the battery in the embodiment is formed from such a battery, the gap formed between the sealing gasket and the separator can be made smaller, similar to the battery in the embodiment described above, thereby preventing internal short circuits.

[0087] Although examples have been described above, the examples are not limited to those described above. Furthermore, the components described above include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that fall within the so-called equivalent range. Moreover, the components described above can be combined as appropriate. Furthermore, at least one of various omissions, substitutions, and modifications of the components can be made without departing from the gist of the examples. [Explanation of symbols]

[0088] 1:Battery 3: Positive electrode 5: Negative electrode 6: Current collector rod 7: Separator 11: Positive electrode can 12:Negative terminal plate 14, 61, 65, 71, 75: Sealing gaskets 17: Opening 18: Interior space 21: Negative electrode filling hole 31: Gasket boss section 32: Gasket flange 33: Gasket peripheral area 34: Separator opposing surface 35: Conical surface 41, 76: Eight radial projections 42 yen 43, 62, 66, 77: Radial process 50: Circumferential direction 51: Separator opening end portion 52: Unevenness 53: Gap 72: 16 radial projections

Claims

1. Positive electrode can, A positive electrode is disposed in the internal space formed in the positive electrode container, A negative electrode is disposed in a negative electrode filling hole formed in the positive electrode, A separator is placed between the negative electrode and the positive electrode, A negative electrode terminal plate is positioned at the opening of the positive electrode can, A current collector rod embedded in the negative electrode, Equipped with a gasket, The aforementioned gasket is The boss portion fixed to the current collector rod, A peripheral portion that seals the gap formed between the negative electrode terminal plate and the positive electrode can, It has a flange portion formed between the boss portion and the peripheral portion, Multiple radial protrusions are formed on the separator-facing surface of the flange portion that is opposite the separator, along the circle surrounding the boss portion. battery.

2. Each of the plurality of radial protrusions is formed such that the width of the protrusion in the circumferential direction, parallel to the tangent line that intersects the portion of the circle with the protrusion, decreases as it moves away from the boss portion. The battery according to claim 1.

3. Each of the plurality of radial protrusions is formed such that the height of the protrusion relative to the separator-facing surface decreases as it moves away from the boss portion. The battery according to claim 1.

4. Each of the plurality of radial protrusions is formed such that the width of the protrusion in the circumferential direction, which is parallel to the tangent line that intersects the portion of the circle with the protrusion, decreases as it moves away from the separator-facing surface. The battery according to claim 1.

5. The projection is formed such that the height of the projection relative to the separator-facing surface decreases as it moves away from the boss portion. The battery according to claim 2.

6. The projection is formed such that the width of the projection in the circumferential direction decreases as it moves away from the separator-facing surface. The battery according to claim 2.

7. The projection is formed such that the width of the projection in the circumferential direction, which is parallel to the tangent line that intersects the projection in the portion of the circle, decreases as it moves away from the separator-facing surface. The battery according to claim 3.

8. The projection is formed such that the width of the projection in the circumferential direction decreases as it moves away from the separator-facing surface. The battery according to claim 5.

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