JP2005056677A - Cylindrical alkaline storage battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylindrical alkaline storage battery having long life and preventing increase in internal resistance and decrease in capacity by solving problems caused by thickening a positive electrode in order to increase capacity. <P>SOLUTION: The cylindrical alkaline storage battery has an electrode group formed by spirally winding a positive electrode 24 and a negative electrode through a separator, and the positive electrode 24 has a positive electrode body part 57 having a thickness of 0.95 mm or more and a tapered winding starting end part 36 and/or a tapered winding finishing end part 40. As suitable embodiment, the thickness T4 at the tip 58 of the tapered winding starting end part 36 and the tapered winding finishing end part 40 is 70% or less of the thickness T3 of the electrode body part 57, and a tilt angle θ1 of an inclined slope 60 in the tapered winding starting end part 36 and/or the tapered winding finishing end part 40 is set to larger than 0° and 60° or less. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cylindrical alkaline storage battery.

  Examples of the alkaline storage battery include a nickel cadmium secondary battery and a nickel hydride secondary battery, depending on the type of active material contained, and these alkaline storage batteries include a cylindrical battery with a cylindrical outer can. is there. The outer can is sealed with a lid with a safety valve, and an electrode group in which a strip-shaped negative electrode and a positive electrode are wound in a spiral shape with a separator interposed therebetween is accommodated therein. The positive electrode is made of, for example, a metal body having a three-dimensional network structure and a positive electrode active material held inside the metal body. The capacities of the positive electrode and the negative electrode are determined by the amount of active material contained in each, but in this type of cylindrical alkaline storage battery, oxygen gas generated at the positive electrode during overcharging is reduced at the negative electrode and the internal pressure is increased. Therefore, the negative electrode capacity is larger than the positive electrode capacity, and the battery capacity is defined by the positive electrode capacity.

  In this type of cylindrical alkaline storage battery, in order to increase the battery capacity, that is, the positive electrode capacity, it is required to increase the amount of the positive electrode active material or to improve the utilization rate. It is known to increase the thickness, area, area and density.

  For example, the cylindrical alkaline storage battery which patent document 1 discloses as what lengthened the positive electrode can be mention | raise | lifted. In this cylindrical alkaline storage battery, at least one electrode plate has both end portions that are tapered and thin, and inclined surfaces are formed on the outer surfaces of both end portions of the positive electrode by pressing or scraping. Thus, by making the both ends of the electrode plate tapered, the winding start end of the electrode plate can be easily wound, and the gap formed at the center of the electrode group is reduced. Is inserted into the gap between the electrode group and the outer can, so that the outer peripheral shape of the electrode group is substantially a perfect circle. That is, in the case of the cylindrical alkaline storage battery of Patent Document 1, it is considered that the volume efficiency is improved and the capacity is increased by extending the both ends of the tapered shape to the gap between the center and the periphery of the electrode group. It is done.

For example, apart from making the electrode plate longer as in Patent Document 1, increasing the thickness of the positive electrode has been performed. When the thickness of the positive electrode is increased, it is not necessary to lengthen the negative electrode and the separator, so the amount of the positive electrode active material can be increased efficiently. Recently, 0.95 mm for an AA size cylindrical alkaline storage battery is available. A positive electrode having the above thickness has been developed.
Japanese Utility Model Publication No. 53-160720 (for example, page 5, line 1 to line 9)

  However, when the thickness of the positive electrode is increased and a cylindrical alkaline storage battery is assembled using a positive electrode having a thickness of 0.95 mm or more, the following problems occur.

One problem is that the battery life is shortened as the thickness of the positive electrode increases.
As the thickness of the positive electrode increases, the distortion of the spiral shape drawn by the positive electrode and the negative electrode increases in the cross section of the electrode group, and the distance between the positive electrode and the negative electrode becomes non-uniform across the longitudinal direction of the positive electrode and the negative electrode. . In particular, when the thickness of the positive electrode is 0.95 mm or more, the variation in the electrode plate spacing increases. When the variation in the distance between the electrode plates becomes large, oxygen gas is locally generated during charging and the internal pressure of the battery rises. Therefore, the safety valve is activated and the alkaline electrolyte leaks to the outside, shortening the battery life.

  For one thing, when the negative electrode winding start end portion extends beyond the positive electrode winding start end portion in the circumferential direction of the electrode group on the outer surface side of the positive electrode, it extends beyond the positive electrode winding start end portion. This is a problem that the negative electrode mixture is peeled off from the negative electrode portion and the negative electrode capacity is reduced.

  After winding the electrode group, in the circumferential direction of the electrode group, in front of the positive electrode winding start end surface, the positive electrode winding start end surface and the separator extending beyond the positive electrode winding start end surface from the inner surface side and the outer surface side of the positive electrode, respectively. A gap is defined by the portion, and the size of the gap is formed according to the thickness of the positive electrode. In a cylindrical alkaline storage battery using an electrode group having such a gap, after the initial charge / discharge, the negative electrode portion positioned radially outside the electrode group via a separator with respect to this gap reduces the gap. As shown, it bends toward the end face of the positive electrode winding. In particular, when the thickness of the positive electrode is 0.95 mm or more, the negative electrode bends in front of the positive electrode winding start end surface, and the negative electrode mixture is peeled off from the bent negative electrode portion, resulting in a decrease in the negative electrode capacity.

  In another case, when the negative electrode winding end end portion extends beyond the positive electrode winding end portion in the circumferential direction of the electrode group on the outer surface side of the positive electrode, the positive electrode winding end end portion is interposed via the separator. There is a problem that the negative electrode core is broken at the portion of the negative electrode superimposed on the outer surface side edge and the internal resistance is increased, or the negative electrode mixture is peeled off and the negative electrode capacity is reduced.

  During winding of the electrode group, the negative electrode portion superimposed on the outer surface side edge of the positive electrode winding end end portion is bent through the separator. In addition, the outer diameter of the electrode group increases at the bent negative electrode portion, and when the electrode group is wound or inserted into the outer can, the bent negative electrode portion is slid with the winding device or outer can of the electrode group. Move. In particular, when the thickness of the positive electrode is 0.95 mm or more, the bending of the negative electrode portion superimposed on the outer surface side edge of the positive electrode winding end is increased. Sliding between the bent negative electrode part and the winding device or the outer can also becomes intense, and the negative electrode core breaks at the bent negative electrode part to increase the internal resistance, or the negative electrode mixture peels from this part. As a result, the negative electrode capacity decreases. In particular, when the inner angle of the bent negative electrode portion is less than 160 degrees, the increase in internal resistance and the decrease in negative electrode capacity become significant.

  The present invention provides a cylindrical alkaline storage battery that solves the above-described problems in a cylindrical alkaline storage battery that is suitable for increasing the capacity by increasing the thickness of the positive electrode, and that has a long life and prevents an increase in internal resistance and a decrease in negative electrode capacity. For the purpose.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided a conductive cylindrical outer can, and a strip-shaped metal body that is accommodated in the outer can together with an alkaline electrolyte and filled with the metal body. A cylindrical alkaline storage battery comprising a positive electrode made of an agent and an electrode group formed by winding a negative electrode in a spiral shape with a separator interposed therebetween, wherein the positive electrode is an end corresponding to each of the start and end of winding of the electrode group And a positive electrode main body having a thickness of 0.95 mm or more between both ends of the positive electrode, and the both ends of the negative electrode are arranged at both ends of the positive electrode in the circumferential direction of the electrode group on the outer surface side of the positive electrode. And at least one of both end portions of the positive electrode is tapered from the positive electrode main body portion toward the tip.

In the above configuration, since the positive electrode has a positive electrode main body having a thickness of 0.95 mm or more, this cylindrical alkaline storage battery is suitable for increasing the capacity.
In the above-described configuration, the positive electrode has a positive electrode main body having a thickness of 0.95 mm or more, and both ends of the negative electrode exceed both ends of the positive electrode in the circumferential direction of the electrode group on the outer surface side of the positive electrode. However, since at least one of both end portions of the positive electrode is tapered from the positive electrode main body portion toward the tip, a decrease in negative electrode capacity and an increase in internal resistance are prevented.

  More specifically, when the positive electrode winding start end portion is tapered, the thickness of the positive electrode at the tip of the positive electrode winding start end portion is reduced, so the positive electrode winding start end surface in front of the positive electrode winding start end surface as viewed in the circumferential direction of the electrode group. The gap defined by the winding start end surface and the portion of the separator that extends from the inner surface side and the outer surface side of the positive electrode beyond the positive electrode winding start end surface is reduced. Therefore, after the initial charge / discharge of this cylindrical alkaline storage battery, the negative electrode portion positioned radially outside the electrode group through the separator with respect to the gap is formed on the end surface of the positive electrode winding so as to reduce the gap. Even if it is bent, the bending is small, so that the negative electrode core is prevented from peeling off from the negative electrode core at the bent negative electrode portion, thereby preventing the negative electrode capacity from being lowered.

  In addition, when the end of the positive electrode winding is formed in a tapered shape, the portion of the negative electrode superimposed on the outer surface of the end of the positive electrode winding via the separator is not the outer edge of the positive end of the positive electrode. It is bent at the boundary between the main body and the positive electrode winding end. In this way, when the negative electrode is bent at the boundary of the positive electrode, the negative electrode is bent less than the case where the negative electrode is bent at the outer surface side edge of the positive electrode winding end without forming the end of the positive electrode winding in a tapered shape, Moreover, since the amount of protrusion of the bent portion of the negative electrode to the radially outer side of the electrode group is small, sliding between the bent negative electrode portion and the electrode group winding device or the outer can is suppressed. Therefore, in this cylindrical alkaline storage battery, the negative electrode core is broken at the portion of the negative electrode superimposed on the positive electrode boundary via the separator and the internal resistance increases, or the negative electrode mixture is peeled off from this portion. The negative electrode capacity is prevented from decreasing.

Furthermore, in the above configuration, when the positive electrode winding start end portion is formed in a tapered shape, the battery life is extended.
More specifically, in the above-described configuration, when the positive electrode winding start end portion is formed in a tapered shape, even if the thickness of the positive electrode main body portion is 0.95 mm or more, the outer surface side of the positive electrode winding start end portion via the separator The portion of the negative electrode superimposed on the positive electrode is bent at the boundary between the positive electrode winding start end and the positive electrode main body, and is bent only small, so that the positive electrode and the negative electrode are neatly wound in a spiral shape. Therefore, in this cylindrical alkaline storage battery, the distance between the positive electrode and the negative electrode is uniform over the longitudinal direction of the positive electrode and the negative electrode, and oxygen gas is locally generated during charging, increasing the internal pressure of the battery. Therefore, the alkaline electrolyte is prevented from decreasing due to the operation of the safety valve, and the life is long.

The invention according to claim 2 is characterized in that both end portions of the positive electrode are tapered from the positive electrode main body portion toward the tip, and outer surfaces at both end portions of the positive electrode are formed as inclined surfaces. .
In the above-described configuration, the outer surfaces of both end portions of the positive electrode are formed as inclined surfaces to more reliably prevent an increase in internal resistance and a decrease in negative electrode capacity, and as a preferred aspect in which the end portion of the positive electrode is tapered. The outer surface of the end portion of the positive electrode is formed as an inclined surface.

In the invention of claim 3, the negative electrode is wound around the outermost periphery of the electrode group, and the negative electrode is wound as a negative electrode main body wound inside the electrode group and as the outermost peripheral portion of the electrode group. A negative electrode thin-walled portion that is thinner than the main body portion.
In the configuration described above, compared to the negative electrode main body wound inside the electrode group, it is wound as the outermost peripheral part of the electrode group, and the negative electrode thin part that has a small contribution to the battery reaction is thinned. The thickness can be increased, and this cylindrical alkaline storage battery is more suitable for increasing the capacity. Here, although the strength of the negative electrode thin portion is lower than that of the negative electrode main body portion, the bending of the portion of the negative electrode thin portion that is superimposed on the boundary of the positive electrode via the separator is small. Breakage of the negative electrode core and peeling of the negative electrode mixture are prevented. Therefore, while this cylindrical alkaline storage battery is suitable for increasing the capacity, an increase in internal resistance and a decrease in negative electrode capacity are prevented.

As a preferable aspect of the above-described configuration, the negative electrode includes a strip-shaped substrate, a first negative electrode active material layer held on the inner surface side of the substrate, and a second negative electrode active material layer held on the outer surface side of the substrate. In the thin portion, the thickness of the second negative electrode active material layer is half or less than the thickness of the first negative electrode active material layer (Claim 4).
As a preferred aspect of the above-described configuration, the thickness of the tapered positive electrode end is preferably 70% or less of the thickness of the positive electrode main body, and the inclination angle of the inclined surface exceeds 0 °. Is preferably 60 ° or less (claim 5).

According to this aspect, since the inner angle of the bent negative electrode portion overlaid on the boundary of the positive electrode via the separator is 160 degrees or more, the broken negative electrode core breaks in the bent negative electrode portion or the negative electrode mixture Peeling is reliably prevented, and an increase in internal resistance and a decrease in negative electrode capacity are reliably prevented.
As a preferred aspect of the above configuration, in the invention of claim 6, the electrode group is wound using a core, and the outer diameter of the core is 30% or less of the outer diameter of the outer can. It is characterized by.

In this aspect, since the outer diameter of the core used for winding the electrode group is 30% or less of the outer diameter of the outer can, the battery life is more reliably prevented from being reduced.
If the ratio of the outer diameter of the core to the outer diameter of the outer can exceeds 30%, the cavity existing in the vicinity of the central axis of the electrode group becomes large, and oxygen gas generated at the positive electrode tends to accumulate in this cavity during charging. Thus, there is a delay in the oxygen gas reduction reaction at the negative electrode. When the oxygen gas reduction reaction is delayed, the internal pressure increases, the safety valve is activated, the alkaline electrolyte leaks, and the battery life is reduced. Therefore, in this embodiment, when the positive electrode, the negative electrode, the separator, and the like are accommodated in the outer can, the electrode group is wound using a core having an outer diameter of 30% or less with respect to the outer diameter of the outer can. The space near the central axis of the anode is made smaller, while the space in which the oxygen gas is temporarily stored is dispersed within the battery by reducing the size of the cavity. The delay of the gas reduction reaction is prevented. Therefore, in this aspect, leakage of the alkaline electrolyte due to the operation of the safety valve accompanying the increase in internal pressure is prevented, and the battery life is more reliably prevented from being reduced.

  Moreover, as a preferable aspect of the above-described configuration, in the invention of claim 7, an end portion disposed between one end of the electrode group and the lid of the outer can and welded to one surface of the positive electrode and A belt-like positive electrode lead having a bent portion bent between the electrode group and the lid body, the electrode group has a cavity corresponding to the core shape, when viewed in cross section The percentage of the cross-sectional area of the electrode group obtained by subtracting the cross-sectional area of the hollow portion divided by the value obtained by subtracting the cross-sectional area of the hollow portion of the electrode group from the cross-sectional area inside the outer can (hereinafter referred to as an electrode) (Group cross-sectional area ratio) is 90% or more and 100% or less.

According to this aspect, since the electrode group cross-sectional area ratio is set to 90% or more, an increase in internal resistance is further prevented.
When the electrode group cross-sectional area ratio is low, the compressive force applied to the electrode group from both sides in the radial direction by the peripheral wall of the outer can is reduced, so that the degree of binding in the electrode group is lowered. If the positive lead welded to one side of the positive electrode is bent and the lid is placed in the opening of the outer can with a low degree of tightness, a large load is applied to the positive electrode where the end of the positive lead is welded. And a breakage occurs at this portion of the positive electrode, increasing the internal resistance. Therefore, in this aspect, by setting the electrode group cross-sectional area ratio to 90% or more, the compressive force applied to the electrode group is increased to increase the tightness of the electrode group, and the positive electrode lead end welded to the positive electrode lead is welded. The part is pressed and held by the negative electrode from both sides in the radial direction via the separator to prevent the positive electrode from being deformed at this point when the positive electrode lead is bent. For this reason, in this aspect, breakage at the portion where the positive electrode lead end of the positive electrode is welded is prevented, and an increase in internal resistance is prevented.

  As described above, in the cylindrical alkaline storage battery of the present invention, the thickness of the positive electrode main body is 0.95 mm or more, which is suitable for high capacity, and at least one positive electrode end of the positive electrode is tapered. Therefore, the negative electrode core adjacent to the vicinity of the tapered positive electrode end through the separator is prevented from breaking the negative electrode core and peeling of the negative electrode mixture, thereby preventing an increase in internal resistance and a decrease in negative electrode capacity, thereby improving quality. doing.

  In the cylindrical alkaline storage battery of the present invention, when the winding start end portion of the positive electrode is tapered, the distance between the positive electrode and the negative electrode is long in the electrode group even if the thickness of the positive electrode main body portion is 0.95 mm or more. It becomes uniform over the direction, and since the local generation of oxygen gas during charging is prevented and the increase in internal pressure is prevented, the life is long.

  Hereinafter, an AA-sized cylindrical nickel-hydrogen secondary battery (hereinafter referred to as a battery A) according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  As shown in FIG. 1, the battery A includes an outer can 10 having a bottomed cylindrical shape with an open upper end. Since the battery A is AA size, the outer can 10 has a size of 13.5 mm to 14.5 mm. It has an outer diameter D (see FIG. 2). The outer can 10 has conductivity and functions as a negative electrode terminal. In the opening of the outer can 10, a conductive cover plate 14 is disposed via a ring-shaped insulating packing 12, and the edge of the opening is caulked. Thus, the insulating packing 12 and the cover plate 14 are fixed in the opening.

  The cover plate 14 has a gas vent hole 16 in the center, and a rubber valve element 18 is disposed on the outer surface of the cover plate 14 so as to close the gas vent hole 16. Further, a cap-shaped positive terminal 20 covering the valve body 18 is fixed on the outer surface of the cover plate 14, and the positive terminal 20 presses the valve body 18 against the cover plate 14. Accordingly, the outer can 10 is normally airtightly closed by the lid plate 14 together with the insulating packing 12 and the valve body 18. On the other hand, when gas is generated in the outer can 10 and its internal pressure increases, the valve body 18 is compressed and the gas is released from the outer can 10 through the gas vent hole 16. That is, the cover plate 14, the valve body 18, and the positive electrode terminal 20 form a safety valve.

  A substantially cylindrical electrode group 22 is accommodated in the outer can 10 together with an alkaline electrolyte (not shown), and the outermost peripheral portion of the electrode group 22 is in direct contact with the peripheral wall of the outer can 10. The electrode group 22 includes a positive electrode 24, a negative electrode 26, and a separator 28. Examples of the alkaline electrolyte include a sodium hydroxide aqueous solution, a lithium hydroxide aqueous solution, a potassium hydroxide aqueous solution, and an aqueous solution obtained by mixing two or more of these. Etc.

  Further, in the outer can 10, a positive electrode lead 30 is disposed between one end of the electrode group 22 and the lid plate 14, and both ends of the positive electrode lead 30 are connected to the positive electrode 24 and the lid plate 14. Therefore, the positive electrode terminal 20 and the positive electrode 24 are electrically connected via the positive electrode lead 30 and the lid plate 14. More specifically, the positive electrode lead 30 has a band shape, and is folded and accommodated between the electrode group 22 and the cover plate 14 when the cover plate 14 is disposed in the opening of the outer can 14. The end portion on the group 22 side is welded in a state of surface contact with one surface of the positive electrode 24. A circular insulating member 32 is disposed between the cover plate 14 and the electrode group 22, and the positive electrode lead 30 extends through a slit provided in the insulating member 32. A circular insulating member 34 is also disposed between the electrode group 22 and the bottom of the outer can 10.

  Referring to FIG. 2, in the electrode group 22, the positive electrode 24 and the negative electrode 26 are alternately overlapped when viewed in the radial direction of the electrode group 22 with the separator 28 interposed therebetween.

  More specifically, the electrode group 22 is provided with a belt-like positive electrode 24, a negative electrode 26, and a separator 28, respectively, and the positive electrode 24 and the negative electrode 26 are spirally formed from one end side of the separator 24 via a core. It is formed by winding. Therefore, one end portions (winding start end portions) 36 and 38 of the positive electrode 24 and the negative electrode 26 are positioned on the center side of the electrode group 22, while the other end portions (winding end end portions) 40 and 42 of the positive electrode 24 and the negative electrode 26. Is positioned on the outer peripheral side of the electrode group 22. The negative electrode 26 is longer than the positive electrode 24, and is wound inside the positive electrode 24 and wound outside the positive electrode 24 in the radial direction of the electrode group 22. The negative electrode winding start end portion 38 extends beyond the positive electrode winding start end portion 36 in the circumferential direction of the electrode group 22 on the radially inner surface side of the positive electrode 24 facing the center side of the electrode group 22. The end 42 extends on the radially outer surface side of the positive electrode 24 facing the outer peripheral side of the electrode group 22 and extends beyond the positive electrode winding end 40 in the circumferential direction of the electrode group 22. Accordingly, the negative electrode 26 sandwiches the positive electrode 24 from both sides across the entire longitudinal direction via the separator 28. The separator 28 is not wound around the outermost periphery of the electrode group 22, and the negative electrode 26 forms the outermost peripheral portion of the electrode group 22. In the outermost peripheral portion of the electrode group 22, the negative electrode 26 and the outer can 10 are mutually connected. Electrically connected. Since the winding core is pulled out from the electrode group 22 after winding, the electrode group 22 has a hollow portion 44 corresponding to the shape of the winding core at the center thereof. Here, the cross-sectional area of the electrode group 22 is generated between the cavity 44 and the electrode group 22 and the outer can from the cross-sectional area inside the outer can 10 as indicated by hatching in FIG. In this embodiment, as a preferred mode, the cross sectional area of the electrode group 22 is obtained by subtracting the cross-sectional area of the cavity 44 from the cross-sectional area inside the peripheral wall of the outer can 10. That is, the percentage of the value divided by the cross-sectional area shown by hatching in FIG. 3B, that is, the electrode group cross-sectional ratio is in the range of 90% to 100%.

Examples of the material of the separator 28 include polyamide fiber nonwoven fabrics, and polyolefin fiber nonwoven fabrics such as polyethylene and polypropylene, to which hydrophilic functional groups are added.
For example, as shown in FIGS. 4 and 5, the negative electrode 26 has a conductive negative electrode core 46 in a strip shape, and the negative electrode mixture 46 holds a negative electrode mixture. The negative electrode core 46 is made of a sheet-like metal material having a plurality of through-holes in the thickness direction, and examples thereof include a punching metal, a metal powder sintered body substrate, an expanded metal, and a nickel net. I can give you. In particular, a punched metal or a metal powder sintered body substrate obtained by molding and sintering a metal powder is suitable for the negative electrode core 46. In FIG. 1 and FIG. 2, the negative electrode core 46 is omitted for convenience of drawing.

The negative electrode mixture is composed of the hydrogen storage alloy particles and the binder capable of storing and releasing hydrogen as the negative electrode active material since the battery A is a nickel hydrogen secondary battery. Instead of the hydrogen storage alloy, for example, The battery A may be a nickel cadmium secondary battery using a cadmium compound, and is not particularly limited. However, a nickel-hydrogen secondary battery is suitable for increasing the capacity of the battery. In the present invention, the hydrogen storage alloy is also referred to as an active material for convenience.
The hydrogen storage alloy particles may be any particles that can store hydrogen generated electrochemically in an alkaline electrolyte when the battery A is charged and can easily release the stored hydrogen during discharge. Such a hydrogen storage alloy is not particularly limited, and examples thereof include AB ₅ type alloys such as LaNi ₅ and MmNi ₅ (Mm is a misch metal). In addition, examples of the binder include hydrophilic or hydrophobic polymers.

The negative electrode mixture described above is filled in the through hole of the negative electrode core body 46 and is held in layers on both surfaces of the negative electrode core body 46 because the negative electrode core body 46 is in a sheet form. Hereinafter, the layer of the negative electrode mixture that covers the inner surface of the negative electrode core 46 and faces the central axis side of the electrode group 22 is referred to as the inner hydrogen storage alloy layer 48 or the inner alloy layer 48, and the outer surface of the negative electrode core 46 is The layer of the negative electrode mixture that is covered and faces the outside of the electrode group 22 is referred to as an outer hydrogen storage alloy layer 50 or an outer alloy layer 50.
In the negative electrode 26, the thickness T <b> 2 of the inner alloy layer 48 is constant from the negative electrode winding start end portion 38 to the negative electrode winding end portion 42. On the other hand, the outer alloy layer 50 changes in thickness between the negative electrode winding start end portion 38 and the negative electrode winding end end portion 42, and the negative electrode 26 has a thickness in the longitudinal direction of the negative electrode core 46 with respect to the thickness of the outer alloy layer 50. Thus, three regions, that is, the negative electrode winding start end portion 38 and the negative electrode winding end portion 42 are sequentially divided into a negative electrode main body portion 52, a negative electrode boundary portion 54, and a negative electrode thin portion 56.

The negative electrode main body 52 is wound inside the electrode group 22, and the positive electrode 24 is disposed on both sides via the separator 28. The thickness of the outer alloy layer 50 in the negative electrode main body 52 is equal to the thickness T2 of the inner alloy layer 48 and is constant.
The negative electrode thin portion 56 is wound around the outer side of the electrode group 22 to form the outermost peripheral portion of the electrode group 22, and surrounds the outer side of the positive electrode winding end end portion 40 via the separator 28, Closely. The thickness T1 of the outer alloy layer 50 in the negative electrode thin portion 56 is constant in the longitudinal direction of the negative electrode core 46, and the thickness of the outer alloy layer 50 in the negative electrode main body 52, that is, the thickness T2 of the inner alloy layer 48. Is also thin. Therefore, in the negative electrode thin portion 56, the inner alloy layer 48 is thicker than the outer alloy layer 50. In the present embodiment, as a preferable aspect, the thickness T1 of the outer alloy layer 50 is set to be equal to or less than half the thickness T2 of the inner alloy layer 48.

  The negative electrode boundary portion 54 is formed between the negative electrode main body portion 52 and the negative electrode thin portion 56. When the negative electrode boundary portion 54 is wound as the electrode group 22, the negative electrode boundary portion 54 is preferably positioned at a position different from the positive electrode winding end portion 40 in the circumferential direction of the electrode group 22. A negative electrode main body 52 is disposed inside the end 40 via a separator 28. However, the circumferential position between the negative electrode boundary portion 54 and the positive electrode winding end portion 40 is not particularly limited. Further, the negative electrode boundary portion 54 has a length L, and the thickness changes in the longitudinal direction of the negative electrode core body 46. More specifically, the thickness of the outer alloy layer 50 at the negative electrode boundary portion 54 gradually decreases at a substantially constant change rate from the negative electrode main body portion 52 toward the negative electrode thin portion 56, and changes from the thickness T2 to the thickness T1.

As described above, the negative electrode 26 preferably includes the negative electrode main body portion 52, the negative electrode boundary portion 54, and the negative electrode thin portion 56, and the negative electrode thin portion 56 is preferably thinner than the negative electrode main portion 52. The thickness of 26 is not particularly limited, and may be constant in the longitudinal direction.
The positive electrode 24 has, for example, a conductive positive electrode core having a strip shape, and a positive electrode mixture is held in the core. The positive electrode core body is a conductor having a three-dimensional network structure, that is, a porous structure, and is made of, for example, a nickel metal body, and the positive electrode mixture is filled in the communicating holes of the metal body.

  The positive electrode mixture includes, for example, a positive electrode active material, an additive, and a binder. As the positive electrode active material, since the battery A is a cylindrical nickel-metal hydride battery, nickel hydroxide particles, or nickel hydroxide particles in which cobalt, zinc, cadmium, or the like is dissolved can be exemplified, but it is particularly limited. Never happen. Further, as additives, in addition to yttrium oxide, cobalt compounds such as cobalt oxide, metal cobalt and cobalt hydroxide, zinc compounds such as metal zinc, zinc oxide and zinc hydroxide, rare earth compounds such as erbium oxide, etc. Examples of the binder include hydrophilic or hydrophobic polymers.

  As shown in FIG. 6 and FIG. 7, the positive electrode 24 has a positive electrode main body portion 57 having a constant thickness T3 in the longitudinal direction, and the thickness T3 is set to 0.95 mm or more. . The positive electrode winding start end portion 36 and the winding end end portion 40 are integrally formed at both ends of the positive electrode main body portion 57, and the positive electrode winding start end portion 36 and the winding end end portion 40 are respectively connected from the positive electrode main body portion 57 to the front end (end surface 58. ) Toward the top. More specifically, the positive electrode winding start end portion 36 and the winding end end portion 40 are formed such that the outer surface on the tip side from the ridge 59 that is a boundary with the positive electrode main body portion 57 is an inclined surface 60, and the thickness of the positive electrode 24 is It gradually decreases at a constant rate of change toward the tip.

  Here, as a preferable aspect in the present embodiment, the inclination angle θ1 of the inclined surfaces 60 is set within a range of more than 0 ° and not more than 60 °, and the positive electrode winding start end portion 36 and the winding end end portion 40 are In the electrode group 22 inserted into the outer can 10, the thickness T4 at the tip is set within a range of 0% to 70% of the thickness T3 of the positive electrode main body portion 57, as schematically shown in FIG. The inner angle θ2 of the portion of the negative electrode 26 that is bent along the outer surface of the positive electrode 24 via the separator 28 and bent at the ridge 59 is maintained at 160 ° or more.

Note that the thickness T3 at the positive electrode main body 57 and the thickness T4 at the tip of the positive electrode 24 are both the thicknesses inside the assembled battery A, and the thickness of the battery A taken by the X-ray CT apparatus. A value obtained by measurement on a cross-sectional image.
Although the battery A described above can be manufactured by applying a normal method, examples of the method for manufacturing the positive electrode 24 and the method for manufacturing (winding) the electrode group 22 will be described below.

  In manufacturing the positive electrode 24, first, for example, a sheet of a nickel metal body and a positive electrode mixture paste to be a positive electrode core are prepared, and the positive electrode mixture paste is filled in the metal body and dried. Next, the metal body filled with the positive electrode mixture in a dry state is compressed from both sides in the thickness direction through a gap between a pair of rolling rolls to adjust the thickness, and then the positive electrode winding start end portion 36 and the positive electrode After forming the inclined surface 60 by cutting a portion that becomes the winding end portion 40, the positive electrode 24 is obtained by cutting into a predetermined dimension. In addition, in the location where the positive electrode lead 30 in the positive electrode 24 is welded, the positive electrode mixture is partially removed by applying ultrasonic waves, for example.

  The electrode group 22 is formed by winding the positive electrode 24 obtained by the above-described manufacturing method and the separately prepared negative electrode 26 and separator 28 using a winding core 61 as shown in FIG. The cylindrical core 61 is formed with a slit 62 that extends in the axial direction of the core 61 and divides the core 61 into two in the radial direction. With the separator 28 sandwiched between the slits 62, the core 61 is rotated in the direction indicated by the arrow 64 in the figure, and the positive electrode 24, the negative electrode 26, and the separator 28 are continuously fed out of the core 61. As a result, the electrode group 22 is wound. At this time, the outer diameter d of the core 61 is not particularly limited, but in the present embodiment, as a suitable aspect, an outer diameter d of 0% or more and 30% or less of the outer diameter D of the outer can 10 (see FIG. 2). The electrode group 22 was wound using the core 61 having the core.

In the battery A having the above-described configuration, since the thickness T3 of the positive electrode main body portion 57 between the positive electrode winding start end portion 36 and the positive electrode winding end portion 40 is 0.95 mm or more, the amount of the positive electrode active material filled in the positive electrode 24 is small. Many are suitable for high capacity.
In addition, since the positive electrode winding start end 36 and the winding end end 40 of the battery A are tapered, an increase in internal resistance and a decrease in negative electrode capacity are prevented.

  In the battery A, the negative electrode winding start end portion 38 extends beyond the positive electrode winding start end portion 36 in the circumferential direction of the electrode group 22 on the outer surface side of the positive electrode 24, and the positive electrode winding start is seen in the circumferential direction of the electrode group 22. A gap is formed in front of the end surface 58 by the positive electrode winding start end surface 58 and the portion of the separator 28 extending beyond the positive electrode winding start end surface 58 from the radially inner and outer surface sides of the positive electrode 24. Then, after the initial charge / discharge of the battery A, as indicated by an arrow 66 in FIG. 7, the gap in front of the positive electrode winding start end surface 58 is reduced radially outward with respect to the gap via the separator 28. The portion of the negative electrode 26 positioned at the end is bent toward the positive electrode winding start end surface 58. Here, in the case of the battery A, even when the thickness T3 of the positive electrode main body portion 57 is 0.95 mm or more, the positive electrode winding start end portion 36 is formed in a tapered shape, and the gap in front of the positive electrode winding start end surface 58 is small. Therefore, since the bending of the negative electrode 26 for reducing the gap is small, peeling of the inner and outer alloy layers 48 and 50 from the negative electrode core 46 at the bent negative electrode 26 is prevented, and the negative electrode capacity is reduced. Is prevented.

From the relationship with the battery life, the thickness of the positive electrode 24 is preferably set within a range of 1.50 mm or less.
Further, in the battery A, the negative electrode winding end portion 42 extends beyond the positive electrode winding end portion 40 in the circumferential direction of the electrode group 22 on the outer surface side of the positive electrode 24, but the positive electrode winding end portion 40 tapers. When the electrode group 22 is wound, the portion of the negative electrode 26 that covers the outer surface of the positive electrode winding end 40 via the separator 28 is bent at the ridge 59 of the positive electrode 24, and the positive electrode winding end Compared to the case where the negative electrode is bent at the outer surface side edge at the end of the positive electrode winding without forming the taper 40, the bending is small. The portion of the negative electrode 26 that is bent only slightly at the ridge 59 also has a small amount of protrusion outward in the radial direction of the electrode group 22, so that when the electrode group 22 is wound or inserted into the outer can 10, the electrode group Sliding with the winding device 22 and the outer can 10 is also suppressed. Thus, in the battery A, even when the thickness T3 of the positive electrode main body 57 is 0.95 mm or more, the bending of the negative electrode 26 at the ridge 59 of the positive electrode 24 is small, so the negative electrode core at the bent negative electrode 26 portion. 46 and the inner and outer alloy layers 48 and 50 from the negative electrode core 46 are prevented from being peeled off, thereby preventing an increase in internal resistance and a decrease in negative electrode capacity.

Further, the battery A includes a negative electrode main body 52 wound inside the electrode group 22 and a negative electrode thin portion 56 wound as the outermost peripheral portion of the electrode group 22. Since the thickness is thinner than the thickness of the negative electrode main body 52, it is further suitable for increasing the capacity, while increasing the internal resistance and reducing the negative electrode capacity are prevented.
In the negative electrode 26, the negative electrode 26 is wound around the outermost periphery of the electrode group 22 as compared with the negative electrode main body 52 in which the positive electrode 24 is disposed on both sides via the separator 28. The negative electrode thin portion 56 in which the positive electrode 24 is disposed only on the inner surface side has a small contribution to the battery reaction. Therefore, in the negative electrode 26, the negative electrode thin portion 56 may be thinner than the negative electrode main portion 52, and the thickness T3 of the positive electrode main portion 57 can be increased by the thickness of the negative electrode thin portion 56. The battery A is further suitable for increasing the capacity. On the other hand, the negative electrode thin portion 56 is thinner than the negative electrode main body portion 52 and thus has lower strength. However, the positive electrode winding end end portion 40 is formed in a tapered shape, and the positive electrode winding end end portion 40 is not an outer surface side edge but a positive electrode. The negative electrode thin portion 56 is bent at the 24 ridges 59. As described above, the bending of the negative electrode thin portion 56 at the ridge 59 is small, and the fracture of the negative electrode core 46 and the peeling of the inner and outer alloy layers 48 and 50 at the bent negative electrode thin portion 56 are prevented. The Therefore, in this cylindrical alkaline storage battery, even when the negative electrode thin portion 56 is wound around the outermost periphery of the electrode group 22, an increase in internal resistance and a decrease in negative electrode capacity are prevented.

  In the battery A, as a preferred embodiment, when the thickness T1 of the outer alloy layer 50 is set to be equal to or less than half the thickness T2 of the inner alloy layer 48, the outer alloy layer 50 does not exist in the negative electrode thin portion 56. During charging, the oxygen gas that has entered between the electrode group 22 and the peripheral wall of the outer can 10 is not reduced, and the safety valve is activated as the internal pressure rises, leading to a decrease in the alkaline electrolyte. The ratio of the thickness T4 of the outer alloy layer is preferably greater than zero.

In the battery A, the thickness T4 at both end surfaces 58 of the positive electrode 24 is set to 0% or more and 70% or less of the thickness T3 of the positive electrode main body 57, and the inclination angle θ1 of the inclined surface 60 exceeds 0 °. Therefore, an increase in internal resistance and a decrease in negative electrode capacity are reliably prevented.
Since the ratio of the thickness T4 to the thickness T3 and the numerical range of the inclination angle θ1 are set in this way, the internal angle θ2 of the portion of the negative electrode 26 bent at the ridge 59 of the positive electrode 24 via the separator 28 is surely 160 degrees or more. Maintained. Therefore, breakage of the negative electrode core 46 and peeling of the negative electrode mixture at the bent negative electrode portion 26 are surely prevented, so that in the battery A, an increase in internal resistance and a decrease in negative electrode capacity are prevented.

In addition, if the positive electrode 24 has a thickness T4 at both ends, the positive electrode mixture is prevented from falling off from the vicinity of both ends of the positive electrode 24 as compared with the case where both ends are pointed. The reduction of the capacity is prevented, which is further suitable for increasing the capacity. Therefore, more preferably, the thickness T4 at both end faces 58 of the positive electrode 24 is set to 5% or more and 70% or less of the thickness T3 of the positive electrode main body portion 57.
Further, in the battery A, since the outer diameter d of the core 61 used for winding the electrode group 22 is 30% or less of the outer diameter D of the outer can 10, the battery life is more reliably prevented from being reduced.

  When the ratio of the outer diameter of the core to the outer diameter D of the outer can 10 exceeds 30%, the cavity 44 existing in the vicinity of the central axis of the electrode group 22 becomes larger, and the oxygen gas generated in the positive electrode 24 during charging is this It tends to accumulate in the cavity 44, and a delay occurs in the oxygen gas reduction reaction at the negative electrode 26. When the oxygen gas reduction reaction is delayed, the internal pressure increases, the safety valve is activated, the alkaline electrolyte leaks, and the battery life is reduced. Therefore, in the battery A, when the positive electrode 24, the negative electrode 26, the separator 28, and the like are accommodated in the outer can 10, a core 61 having an outer diameter d of 30% or less with respect to the outer diameter D of the outer can 10 is used. By winding the electrode group to make the cavity 44 near the central axis of the electrode group 22 small, the space for temporarily storing oxygen gas by the amount of the cavity 44 being reduced is dispersed inside the battery, so that the entire anode 26 The oxygen gas reduction reaction is efficiently advanced to prevent delay of the oxygen gas reduction reaction. Therefore, in the battery A, the leakage of the alkaline electrolyte due to the operation of the safety valve accompanying the increase in internal pressure is prevented, and the battery life is more reliably prevented from decreasing.

In battery A, since the electrode group cross-sectional area ratio is set to 90% or more, an increase in internal resistance is further prevented.
When the electrode group cross-sectional area ratio is low, the compressive force applied to the electrode group 22 from both sides in the radial direction by the peripheral wall of the outer can 10 becomes small, so the degree of binding in the electrode group 22 is low. When the positive electrode lead 30 whose end is welded to one surface of the positive electrode 24 is bent and the cover plate 14 is disposed in the opening of the outer can 10 in a state where the tightness is low, the end of the positive electrode lead 30 is welded. A large load is applied to the portion of the positive electrode 24, and the portion of the positive electrode 24 is broken to increase the internal resistance. Therefore, in the battery A, by setting the electrode group cross-sectional area ratio to 90% or more, the compressive force applied to the electrode group 22 is increased to increase the tightness of the electrode group 22, and the end of the positive electrode lead 30 is welded. The portion of the positive electrode 24 is pressed and clamped by the negative electrode 26 from both sides in the radial direction via the separator 28 to prevent the positive electrode 24 from being deformed at this portion when the positive electrode lead 30 is bent. Therefore, in the battery A, breakage at the portion where the positive electrode lead end portion 30 of the positive electrode 24 is welded is prevented, and an increase in internal resistance is prevented.

The present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the battery A may be AAA size, but the thickness T3 of the positive electrode main body 57 and the outer can 10 From the relationship with the outer diameter D, the present invention is suitable for an AA size cylindrical alkaline storage battery.
Further, only one of the positive electrode winding start end portion 36 and the winding end end portion 40 may be tapered. However, if both the positive electrode winding start end portion 36 and the winding end end portion 40 are formed in a tapered shape, it is possible to more reliably prevent a decrease in battery life and a decrease in negative electrode capacity as compared with the case of only one. And increase in internal resistance can be prevented, which is preferable. When only one of the positive electrode winding start end portion 36 and the winding end end portion 40 is tapered, the positive electrode winding start end portion 36 is tapered rather than the positive electrode winding end end portion 40. This is preferable because the spiral shape of 22 is improved and the battery life is extended.

Examples 1 to 8, Comparative Examples 1 and 2
1. Assembling of the battery As Example 1, only the positive electrode winding start end portion 36 was tapered and the positive electrode winding end end portion 40 was not formed in a tapered shape. 100 AA-sized cylindrical nickel-metal hydride secondary batteries having the configurations shown in FIGS.

As Example 2, only the positive electrode winding end portion 40 was tapered and the positive electrode winding start end portion 36 was not formed in a tapered shape, as shown in FIGS. 1, 2, 4, 5, 6 and 7. 100 AA-sized cylindrical nickel-metal hydride secondary batteries having the structure shown were assembled.
As Examples 3 to 8, 100 AA-sized cylindrical nickel-metal hydride secondary batteries having the configurations shown in FIGS. 1, 2, 4, 5, 6 and 7 were assembled.

  As Comparative Example 1, 100 cylindrical nickel-metal hydride secondary batteries having the same configuration as Example 1 except that the positive electrode winding start end portion 36 was not formed in a tapered shape were assembled. 100 cylindrical nickel-hydrogen secondary batteries having the same configuration as in Example 1 were assembled except that the positive electrode winding start end portion 36 was not tapered and the thickness of the positive electrode 24 was 0.90 mm.

  Here, Table 1 shows the length and width of the positive electrode in Examples 1 to 8 and Comparative Examples 1 and 2, and the length, width and thickness of the negative electrode and separator, and Table 2 shows Examples 1 to 8 and In Comparative Examples 1 and 2, the thickness T3 of the positive electrode main body, the inclination angle θ1 of the inclined surface, the thickness T4 at the positive electrode end surface, and the ratio of the thickness T4 to the thickness T3 are shown.

2. Battery Characteristic Evaluation Test 1) Negative electrode mixture peeling and negative electrode core breakage In each of Examples 1 to 8 and Comparative Examples 1 and 2, after winding the electrode group 22, in the vicinity of the positive electrode winding end 40 The number of fractures in the negative electrode core 46 on the negative electrode winding end 42 side was counted. In addition, after performing a short circuit inspection on the batteries of each Example and Comparative Example, after charging and discharging the batteries that were not short-circuited, the cross section of each battery was observed using X-ray CT, and the positive electrode winding start end The number of occurrences of peeling of the negative electrode mixture on the negative electrode winding start end 40 side in the vicinity of the portion 36 was counted, and the internal angle θ2 of the portion of the negative electrode plate 26 bent in the vicinity of the positive electrode winding end end portion 40 was measured. These results are shown in Table 1.

2) Battery life (cycle characteristics)
About each cylindrical alkaline storage battery of Examples 1-8 and Comparative Examples 1 and 2, first charge / discharge was first performed, and the battery mass was measured. Next, after charging each of these batteries with -ΔV with a current amount equivalent to 1 It, a pause of 1 hour is performed, and charging and discharging are performed until the battery voltage reaches 1.0 V with a current amount equivalent to 1 It as one cycle. This charging / discharging was performed 200 cycles. Then, after discharging at the 200th cycle, the battery mass was measured, and the difference from the previously measured battery mass was determined to determine the decrease (mg) of the battery mass (electrolyte) due to the charge / discharge cycle. It was shown in 2. In addition, the amount of reduction is an average value excluding the short-circuited from 100 pieces.

From Table 2, the following is clear.
Comparing Comparative Example 1 and Comparative Example 2, when the thickness of the positive electrode 24 is 0.95 mm or more, the negative electrode mixture is peeled off at the negative electrode winding start end 38 side, and the negative electrode core body 46 at the negative electrode winding end end 42 side. Are likely to break, short circuit, and lose mass.
Comparing Examples 1 and 2 and Comparative Example 1, if the positive electrode winding start end portion 36 is tapered, it is possible to prevent the negative electrode mixture from being peeled off at the negative electrode winding start end portion 38 side. If the portion 40 is tapered, it is possible to prevent the negative electrode core body 46 from being broken on the negative electrode winding end portion 42 side. Further, if at least one of the positive electrode winding start end portion 36 and the winding end end portion 40 is tapered, a short circuit and a decrease in mass can be suppressed. However, when only the positive electrode winding start end portion 36 is tapered. However, it is possible to suppress a short circuit and a decrease in mass as compared with a case where only the positive electrode winding end portion 40 is tapered.

Comparing Example 6 and Example 7, when the inclination angle θ1 exceeds 60 degrees and the inner angle θ2 of the bent portion of the negative electrode plate 26 is smaller than 160 degrees, the number of short circuits and the amount of mass decrease increase. The negative electrode mixture is easily peeled off at the negative electrode winding start end portion 38 side and the negative electrode core body 46 is easily broken at the negative electrode winding end end portion 42 side.
When Example 7 and Example 8 are compared, if the ratio of the thickness T4 at the end face 58 to the thickness T3 of the positive electrode main body 57 exceeds 70%, the number of short circuits and the amount of mass decrease increase, and the negative electrode winding start end. The negative electrode mixture is peeled off at the portion 38 side, and the negative electrode core 46 is easily broken at the negative electrode winding end portion 42 side.

1 is a partially cutaway perspective view of a cylindrical nickel-metal hydride secondary battery according to an embodiment of the present invention. It is a cross-sectional view of the battery of FIG. 2A is a schematic diagram showing a cross-sectional area of an electrode group in the battery of FIG. 1, and FIG. 2B is a schematic diagram showing a cross-sectional area obtained by subtracting the cross-sectional area of a cavity from the cross-sectional area inside the outer can. It is the perspective view which expanded and showed the negative electrode used for the battery of FIG. It is a side view of the negative electrode of FIG. It is the perspective view which expanded and showed the positive electrode used for the battery of FIG. It is explanatory drawing of the bending of the negative electrode which showed typically the negative electrode bent in the side view of the positive electrode of FIG. 6 in the both ends vicinity of this positive electrode. It is explanatory drawing of the winding method of the electrode group used for the battery of FIG.

Explanation of symbols

24 Positive electrode 26 Negative electrode 28 Separator 36 Positive electrode winding start end portion 40 Positive electrode winding end end portion 57 Positive electrode main body portion 58 End surface 59 Edge 60 Inclined surface

Claims (7)

A conductive cylindrical outer can;
The outer can is housed together with an alkaline electrolyte, and includes a strip-shaped metal body, a positive electrode composed of a positive electrode mixture filled in the metal body, and an electrode group obtained by winding the negative electrode in a spiral shape with a separator interposed therebetween. In cylindrical alkaline storage battery,
The positive electrode has an end corresponding to each of the winding start and the winding end of the electrode group, and a positive electrode main body having a thickness of 0.95 mm or more between both ends of the positive electrode,
Both ends of the negative electrode extend beyond the both ends of the positive electrode in the circumferential direction of the electrode group on the outer surface side of the positive electrode,
At least one of both end portions of the positive electrode is formed in a tapered shape from the positive electrode main body portion toward the tip, and is a cylindrical alkaline storage battery. Both ends of the positive electrode are tapered from the positive electrode main body toward the tip,
2. The cylindrical alkaline storage battery according to claim 1, wherein an outer surface of the positive electrode is formed as an inclined surface at the tapered positive electrode end portion. The negative electrode is wound around the outermost periphery of the electrode group,
The negative electrode is
A negative electrode main body wound inside the electrode group;
The cylindrical alkaline storage battery according to claim 1, wherein the cylindrical alkaline storage battery is wound as an outermost peripheral portion of the electrode group and has a thin negative electrode portion thinner than the negative electrode main body portion. The negative electrode is
A belt-shaped substrate;
A first negative electrode active material layer held on the inner surface side of the substrate;
A second negative electrode active material layer held on the outer surface side of the substrate,
4. The cylindrical alkaline storage battery according to claim 3, wherein the thickness of the second negative electrode active material layer is half or less than the thickness of the first negative electrode active material layer in the negative electrode thin portion.   The thickness at the tip of the tapered positive electrode end is 70% or less of the thickness of the positive electrode main body, and the inclination angle of the inclined surface is more than 0 ° and 60 ° or less. Item 3. A cylindrical alkaline storage battery according to Item 2.   2. The cylindrical alkaline storage battery according to claim 1, wherein the electrode group is wound using a winding core having an outer diameter of 30% or less compared to the outer diameter of the outer can. An end portion disposed between one end of the electrode group and the lid of the outer can and welded to one surface of the positive electrode and a bent portion bent between the electrode group and the lid body A belt-like positive electrode lead having
The electrode group is wound using a core, and has a hollow portion corresponding to the core shape,
The value obtained by subtracting the cross-sectional area of the electrode group obtained by subtracting the cross-sectional area of the cavity portion from the value obtained by subtracting the cross-sectional area of the cavity portion of the electrode group from the cross-sectional area inside the outer can when viewed in cross section. The cylindrical alkaline storage battery according to claim 1, wherein the percentage of the battery is 90% or more and 100% or less.

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