Electrodes and lead-acid batteries

Abstract

To provide an active material holding member, an electrode, and a lead-acid battery capable of reducing leakage of an active material.SOLUTION: An active material holding member 11 comprises a plurality of cylindrical members 12, each being formed by winding a base material 13 around at least once. Each cylindrical member 12 has a proximity part 13c that is a portion close to the adjacent cylindrical members 12. At least one of the plurality of cylindrical members 12 is a specific cylindrical member 12A that is formed so that the twist length LW of the base material 13 is equal to or less than a quarter of the peripheral length of each cylindrical member 12. When seeing the cylindrical member 12 so that a winding end part 13d of the base material 13 can be confirmed visually and defining a portion of the base material 13 extending in a winding direction of the base material 13 from the proximity part 13c to the winding end part 13d as a base material end part surface 13f, the twist length LW is a length in a circumferential direction of a portion forming a first end part 13a or a second end part 13b of the cylindrical member 12 on the base material end part surface 13f.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] One aspect of the present invention is , electric This relates to electrodes and lead-acid batteries. [Background technology]

[0002] Lead-acid batteries are widely used as secondary batteries for industrial or consumer use, and there is particularly high demand for backup lead-acid batteries for electric vehicles (e.g., automotive lead-acid batteries, so-called batteries), UPS (Uninterruptible Power Supply), power sources for disaster prevention (emergency) radio, telephone power sources, etc.

[0003] In lead-acid batteries, an active material holding member having a plurality of tubular members arranged side by side as a tubular member capable of holding (accommodating) an active material may be used. For example, a lead-acid battery includes an active material holding member having a tubular member, an electrode having a metal core (current collector) inserted into the tubular member, and an electrode material (electrode material containing an active material) filled between the tubular member and the metal core (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 8-203506 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, as the cylindrical member of the active material holding member, a cylindrical member formed by winding a substrate may be used. In such a cylindrical member, the wound end of the substrate is fixed to the outer circumferential surface (surface) of the cylindrical member at the end of the cylindrical member in the axial direction of the cylindrical member. However, due to an external stress applied to the substrate, the substrate may peel off from the wound end (roll up from the outer circumferential surface of the cylindrical member), causing the active material to leak from the cylindrical member. Therefore, from the viewpoint of improving the battery characteristics, it is required to reduce the leakage of the active material from the active material holding member having a cylindrical member.

[0006] Therefore, an object of one aspect of the present invention is to reduce leakage of active material. , electric The present invention aims to provide a lead-acid battery and a lead-acid battery. [Means for solving the problem]

[0007] An active material holding member according to one aspect of the present invention comprises a plurality of tubular members extending in a first direction between a first end and a second end and formed by winding a substrate at least one revolution, the tubular members being arranged in a second direction perpendicular to the first direction and having a proximal portion which is a portion proximal to an adjacent tubular member in the second direction, and at least one of the plurality of tubular members being a specific tubular member formed such that the rolled length of the substrate is ¼ or less of the circumferential length of the tubular member, the rolled length being the length along the circumferential direction of the portion of the substrate end surface which forms the first end or second end of the tubular member when the tubular member is viewed from a third direction perpendicular to both the first and second directions so that the wound end of the substrate is visible.

[0008] An active material holding member according to one aspect of the present invention comprises a plurality of tubular members extending in a first direction between a first end and a second end and formed by winding a substrate at least one revolution, the tubular members being arranged in a second direction perpendicular to the first direction and having a proximal portion which is a portion proximal to an adjacent tubular member in the second direction, and at least one of the plurality of tubular members being a specific tubular member formed such that the rolled length of the substrate is ¼ or less of the circumferential length of the tubular member, the rolled length being the length along the circumferential direction of the portion which formed the first end or the second end on the substrate end surface which is the rolled portion when the substrate is rolled from the rolled end to the proximal portion when the tubular member is viewed from a third direction perpendicular to both the first and second directions so that the rolled end of the substrate is visible.

[0009] In the cylindrical member formed by winding the substrate at least once, at least one of the first end and the second end, which are the ends in the extension direction, the substrate tends to be easily rolled up (easily peeled off) from the wound end due to external stress acting on the outer circumferential surface (surface) of the cylindrical member. The active material holding member according to one aspect of the present invention is arranged in the second direction, and even if the substrate is rolled up in the opposite direction to the winding direction, there is little possibility that the substrate will roll up beyond the adjacent portion where the adjacent cylindrical members are close to each other. Furthermore, the specific cylindrical member provided in the active material holding member of the present invention is formed so that the rolled length of the substrate is 1 / 4 or less of the circumferential length of the cylindrical member, so that even if the substrate is rolled up from the wound end, the amount of the substrate being rolled up is kept short, and leakage of the active material can be reduced.

[0010] In the active material holding member according to one aspect of the present invention, the cylindrical member may be formed by spirally winding a strip-shaped base material. In this configuration, even in an active material holding member including a cylindrical member formed by spirally winding a base material, the amount of curling of the base material is kept short and suppressed, thereby reducing leakage of the active material.

[0011] In an active material holding member according to one aspect of the present invention, the tubular member may have a roll-up prevention portion at the first end or the second end that straddles the joint between the inner circumferential side substrate and the outer circumferential side substrate and fixes the substrates to each other, the roll-up prevention portion being provided on the outer circumferential surface side of the tubular member. In this configuration, for example, the inner circumferential side substrate and the outer circumferential side substrate are integrally fixed from the outer circumferential surface side at the first end or the second end of the tubular member, so that roll-up of the wound end can be more reliably prevented.

[0012] The multiple tubular members of an active material holding member according to one aspect of the present invention may include two types of tubular members: a first tubular member in which the substrate is wound right-handed (clockwise) when viewed from the second end side in the first direction, and a second tubular member in which the substrate is wound left-handed (counterclockwise).

[0013] In the cylindrical member formed by winding the base material at least once, at least one of the first end and the second end, which are the ends in the extension direction, the base material tends to be easily rolled up (easily peeled off) from the wound end due to an external stress acting in one direction on the outer circumferential surface of the cylindrical member. In this configuration, the direction in which the wound end peels off is a mixture of cylindrical members wound clockwise and cylindrical members wound counterclockwise, so even if the direction in which the external stress acts and the direction in which the clockwise wound cylindrical member rolls up are the same, the direction in which the external stress acts and the direction in which the wound end of the counterclockwise wound cylindrical member rolls up are opposite to each other, so the wound end of the counterclockwise wound cylindrical member will not roll up. In other words, by providing two types of cylindrical members, a first cylindrical member with a base material wound clockwise and a second cylindrical member with a base material wound counterclockwise, the risk of the wound end rolling up due to an external stress acting in one direction is dispersed. As a result, leakage of the active material can be reduced.

[0014] In the active material holding member according to one aspect of the present invention, all of the multiple cylindrical members may be unified as cylindrical members having a base material wound clockwise or counterclockwise when viewed from the second end side in the first direction. In this configuration, there is only one type of cylindrical member, which can reduce procurement costs.

[0015] In the active material holding member according to one aspect of the present invention, the cylindrical member may be formed by spirally winding a band-shaped substrate from the second end to the first end, with an overlapping portion in which a portion of the substrate on the inner circumference side is covered by the substrate on the outer circumference side. Here, since a portion of the substrate on the inner circumference side is covered by the substrate on the outer circumference side, the wound end on the second end side is less likely to roll up than the wound end on the first end side. In this configuration, one of the wound ends formed at both ends of the cylindrical member can be made less likely to roll up, thereby reducing leakage of the active material. Furthermore, in this configuration, leakage of the active material from the joint between the band-shaped substrates adjacent in the extension direction can be reduced.

[0016] In the active material holding member according to one aspect of the present invention, the cylindrical members may be arranged such that the overlapping portions of adjacent cylindrical members in the second direction do not come into contact with each other. Here, the overlapping portions protrude radially from the outer circumferential surface of the cylindrical members. The cylindrical members may also be arranged with some gaps between them. When the overlapping portions of adjacent cylindrical members overlap or cross each other, the overlapping portions come into close contact with each other, hindering the flow of the electrolyte or the gas generated in the battery case. In this configuration, since there are no portions where the overlapping portions come into close contact with each other, an environment that is excellent for the flow of the electrolyte or the gas generated in the battery case can be provided when the active material holding member is housed in the battery case.

[0017] An electrode according to one aspect of the present invention may have the above-mentioned active material holding member, first sealing portions sealing first ends of the plurality of cylindrical members, second sealing portions sealing second ends of the plurality of cylindrical members, and an active material filled in the cylindrical members. With this configuration, it is possible to provide an electrode including the above-mentioned active material holding member.

[0018] In an electrode according to one aspect of the present invention, the rolled-up height of the base material in the tubular member is equal to or less than the length in the first direction of an inserted portion where the first sealing portion is inserted into the tubular member, and the rolled-up height may be the length in the first direction in the vicinity of the end surface of the base material. The rolled-up height is the length in the first direction in the vicinity of the end surface of the base material.

[0019] In an electrode having this configuration, the base material may roll up from the winding end to the adjacent part, but even if the base material rolls up from the end of the tubular member, the first sealing part is inserted into that part. Therefore, the first sealing part prevents the active material from falling down to the first end of the tubular member, and the amount of active material filled inside the tubular member is reduced by the amount of the first sealing part inserted. This makes it possible to reduce leakage of the active material from the rolled part, even if the base material rolls up from the winding end to the adjacent part.

[0020] A lead-acid battery according to one aspect of the present invention may include the above-mentioned electrode and a battery case that houses an active material holding member. In this configuration, a lead-acid battery including the above-mentioned active material holding member can be provided.

[0021] The lead-acid battery according to one aspect of the present invention further includes a pressing member arranged in contact with a part of the cylindrical member, and the pressing member may be in contact with at least a part of the end surface of the substrate of the cylindrical member. In this configuration, the end surface of the substrate including the winding end is pressed by the pressing member, so that the substrate can be prevented from rolling up from the winding end.

[0022] A lead-acid battery according to one aspect of the present invention includes an electrode having the active material holding member, a first sealing portion sealing first ends of the cylindrical members, a second sealing portion sealing second ends of the cylindrical members, and an active material filled in the cylindrical members, and a battery case that houses the active material holding member, and the electrode may be housed in the battery case such that the first sealing portion is located vertically downward in the battery case and the second sealing portion is located vertically upward in the battery case. In this configuration, the above-mentioned configuration that can reduce leakage of the active material at the vertically downward end of the cylindrical member where the active material is likely to be microparticulated is provided, and therefore leakage of the active material can be effectively reduced.

[0023] A lead-acid battery according to one aspect of the present invention includes an electrode having the active material holding member, a first sealing portion sealing first ends of the cylindrical members, a second sealing portion sealing second ends of the cylindrical members, and an active material filled in the cylindrical members, and a battery case that houses the active material holding member, and the electrode may be housed in the battery case such that the first sealing portion is located vertically upward in the battery case and the second sealing portion is located vertically downward in the battery case. In this configuration, the wound end that is easily rolled up is arranged to be upward, thereby reducing leakage of the active material.

[0024] In the lead-acid battery according to one aspect of the present invention, the cylindrical member may have a first outer peripheral surface facing one side in the third direction and a second outer peripheral surface facing the other side in the third direction, and the wound ends of all the cylindrical members may be disposed on the first outer peripheral surface or the second outer peripheral surface. In this configuration, the positions of the wound ends of the cylindrical members are uniformly arranged on either the first outer peripheral surface or the second outer peripheral surface, thereby improving workability during assembly.

[0025] In a lead-acid battery according to one aspect of the present invention, the cylindrical member may have a first outer circumferential surface facing one side in the third direction and a second outer circumferential surface facing the other side in the third direction, and may include a cylindrical member in which the winding end is disposed on the first outer circumferential surface, and a cylindrical member in which the winding end is disposed on the second outer circumferential surface. In this configuration, the positions of the winding end of the cylindrical member are distributed between the first outer circumferential surface and the second outer circumferential surface, so that the risk of the winding end being rolled up by an external stress acting in one direction is dispersed. As a result, leakage of the active material can be reduced.

[0026] In the lead-acid battery according to one aspect of the present invention, the cylindrical members having the winding end disposed on the first outer peripheral surface and the cylindrical members having the winding end disposed on the second outer peripheral surface may be alternately arranged in the second direction. In this configuration, the positions of the winding end of the cylindrical members are regularly distributed between the first outer peripheral surface and the second outer peripheral surface, so that the risk of the winding end being rolled up by an external stress acting in one direction is dispersed. As a result, leakage of the active material can be effectively reduced. Effect of the Invention

[0027] According to the present invention, leakage of active material can be reduced. [Brief description of the drawings]

[0028] [Figure 1] FIG. 1 is a cross-sectional view of a lead-acid battery according to one embodiment, as viewed from the Y-axis direction. [Diagram 2] FIG. 2 is a cross-sectional view of the lead-acid battery according to one embodiment as viewed from the Z-axis direction. [Diagram 3] Fig. 3(A) is a perspective view showing the configuration of a tubular member according to one embodiment, and Fig. 3(B) is a perspective view showing the configuration of a tubular member according to a modified example. [Figure 4] FIG. 4 is a front view showing the active material holding member as viewed from the Y-axis direction. [Diagram 5]Fig. 5(A) is a schematic diagram showing the winding end portion on the first end side as viewed from the Z-axis direction, and Fig. 5(B) is a schematic diagram showing the winding end portion on the second end side as viewed from the Z-axis direction. [Figure 6] Fig. 6(A) is an enlarged front view of the winding end portion on the first end side as viewed from the Y-axis direction, and Fig. 6(B) is an enlarged front view of the winding end portion on the second end side as viewed from the Y-axis direction. [Figure 7] Fig. 7(A) is a perspective view showing a first tubular member with a wound end portion on a first end side rolled up, and Fig. 7(B) is a perspective view showing a first tubular member with a wound end portion on a second end side rolled up. [Figure 8] Fig. 8(A) is a perspective view showing the second cylindrical member with the wound end portion on the first end side rolled up, and Fig. 8(B) is a perspective view showing the second cylindrical member with the wound end portion on the second end side rolled up. [Figure 9] Fig. 9(A) is a front view of the lower connecting member as viewed from the Y-axis direction, and Fig. 9(B) is a plan view of a portion of the lower connecting member as viewed from the Z-axis direction. [Figure 10] FIG. 10 is a front view of the connection portion between the lower connecting member and the tubular member as viewed from the Y-axis direction. [Figure 11] FIG. 11 is a front view of the first end portion as viewed from the Y-axis direction. [Figure 12] Fig. 12(A) is a front view of the lower connecting member as viewed from the Y-axis direction, and Fig. 12(B) is a plan view of the lower connecting member as viewed from the Z-axis direction. [Figure 13] FIG. 13 is a front view showing an active material holding member according to a modified example as viewed from the Y-axis direction. [Figure 14] Fig. 14(A) is a schematic diagram showing a winding end portion on a first end side according to a modified example as viewed from the Z-axis direction, and Fig. 14(B) is a schematic diagram showing a winding end portion on a second end side according to a modified example as viewed from the Z-axis direction. [Figure 15] Fig. 15(A) is a schematic diagram showing a winding end portion on a first end side according to a modified example as viewed from the Z-axis direction, and Fig. 15(B) is a schematic diagram showing a winding end portion on a second end side according to a modified example as viewed from the Z-axis direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Hereinafter, a lead-acid battery according to an embodiment will be described with reference to the drawings. In the description of the drawings, the same elements are given the same reference numerals and duplicated descriptions will be omitted.

[0030] In this specification, a numerical range indicated using "~" indicates a range including the numerical values ​​described before and after "~" as the minimum and maximum values, respectively. In the numerical ranges described in stages in this specification, the upper limit or lower limit of a numerical range of a certain stage can be arbitrarily combined with the upper limit or lower limit of a numerical range of another stage. "A or B" may include either A or B, or may include both. Unless otherwise specified, the materials exemplified in this specification may be used alone or in combination of two or more types. The term "process" includes not only an independent process, but also a process that cannot be clearly distinguished from other processes as long as the intended effect of the process is achieved.

[0031] An example of a lead-acid battery 100 according to this embodiment will be described with reference to Figures 1 to 3. For ease of description, the drawings may be labeled with an X-axis, a Y-axis, and a Z-axis that are perpendicular to one another. The X-axis direction (third direction) is the direction in which the cylindrical members 12 that constitute the positive electrode (electrode) 10 are arranged, the Y-axis direction (second direction) is the direction in which the positive electrodes 10 and the negative electrodes 20 are arranged alternately with the separators 30 interposed therebetween, and the Z-axis direction (first direction) is the direction along the extension direction of the cylindrical members 12 and is an axis along the vertical direction.

[0032] As shown in Figures 1 and 2, a lead-acid battery 100 according to one embodiment includes an electrode group 110, a battery case 120 that houses the electrode group 110, connecting members 130a, 130b connected to the electrode group 110, poles 140a, 140b connected to the connecting members 130a, 130b, a liquid inlet plug 150 that closes the liquid inlet of the battery case 120, and a support member 160 connected to the battery case 120.

[0033] The electrode group 110 includes a plurality of positive electrodes 10, a plurality of negative electrodes 20, and a plurality of separators 30. The positive electrodes 10 and the negative electrodes 20 are alternately arranged in the Y-axis direction with the separators 30 interposed therebetween. The space around the positive electrodes 10 between the separators 30 is filled with an electrolyte 40. The material of the separator 30 is not particularly limited as long as it prevents electrical connection between the positive electrodes 10 and the negative electrodes 20 and allows the electrolyte 40 to pass through. Examples of the material of the separator 30 include a mixture of microporous polyethylene, glass fiber, and synthetic resin.

[0034] The positive electrode 10 is, for example, a plate-shaped electrode. The positive electrode 10 includes an active material holding member 11, a plurality of core metals 14, a positive electrode material (active material) 16, a lower seat (first sealing portion) 51, an upper seat (second sealing portion) 61, a connecting portion 18a, and an ear portion 18b.

[0035] The active material holding member 11 includes a plurality of cylindrical members 12. The plurality of cylindrical members 12 are arranged adjacent to each other in a row along the X-axis direction. The plurality of cylindrical members 12 form a group of tubes (clad tubes) for holding active material. The cylindrical members 12 extend in the Z-axis direction. The structure in which the plurality of cylindrical members 12 are arranged side by side can be formed by using cylindrical members 12 that are separate from each other.

[0036] The cylindrical member 12 extends in one direction (first direction) between the first end 13a and the second end 13b and is formed into a cylindrical shape. The cylindrical member 12 may be formed into an elliptical cylindrical shape or a square cylindrical shape (for example, a square cylindrical shape with rounded corners). The center of gravity in the cross section of the cylindrical member 12 may be used as the central axis of the cylindrical member 12. The cylindrical member 12 is a member for holding an active material of a battery, and can hold (contain) the active material inside (internal space) of the cylindrical member 12. The "active material" includes both the active material after chemical conversion and the raw material of the active material before chemical conversion.

[0037] The cylindrical member 12 includes a first cylindrical member 12R formed by winding the substrate 13 clockwise when viewed in the axial direction from the second end 13b side as shown in Fig. 7(A), and a second cylindrical member 12L formed by winding the substrate 13 counterclockwise when viewed in the axial direction from the second end 13b side as shown in Fig. 8(A). The multiple cylindrical members 12 constituting the active material holding member 11 of this embodiment include two types of cylindrical members 12, the first cylindrical member 12R in which the substrate 13 is wound clockwise when viewed from the second end 13b side in the Z-axis direction, and the second cylindrical member 12L in which the substrate 13 is wound counterclockwise.

[0038] More specifically, in the active material holding member 11 of this embodiment, first cylindrical members 12R formed by winding the substrate 13 clockwise and second cylindrical members 12L formed by winding the substrate 13 counterclockwise are alternately arranged in the X-axis direction. The first cylindrical members 12R and second cylindrical members 12L may be arranged, for example, in a regular alternating two-by-two arrangement or in a random arrangement.

[0039] The substrate 13 may be wound at least once, may be wound more than once, or may be wound multiple times. In the cylindrical member 12 of this embodiment, the substrate 13 is wound multiple times. In this embodiment, the substrate 13 is wound in a spiral shape as shown in FIG. 3(A). "Spiral shape" means that the substrate 13 advances in the extension direction of the central axis while going around a periphery at a predetermined distance from the central axis extending in a predetermined direction. The substrate 13 may be wound in a spiral shape as shown in FIG. 3(B). When the substrate 13 is wound in a spiral shape, for example, the rectangular substrate 13 can be wound along one side of the substrate 13 to form the cylindrical member 12.

[0040] "Spiral" means to rotate in the same plane. For example, in the case of a spiral shape, the tubular member 12 stretches as the substrate 13 is wound, whereas in the case of a spiral shape, the tubular member 12 thickens as the substrate 13 is wound, but the tubular member 12 does not stretch. The winding direction in the case of a spiral shape means the direction of rotation of the substrate 13 relative to the central axis. The winding direction in the case of a spiral shape means the winding direction when the substrate 13 is wound from the inner layer to the outer layer of the tubular member 12.

[0041] 4, the tubular member 12 has end faces perpendicular to the axial direction of the tubular member 12 at, for example, the first end 13a and the second end 13b. The end faces may be formed by spirally winding a strip-shaped base material 13 to form the tubular member 12, and then cutting both ends of the tubular member 12 perpendicular to the axial direction of the tubular member 12. The width (size in the short direction) of the strip-shaped base material 13 is 5 mm to 35 mm. In addition, by using a base material 13 having a shape that provides end faces perpendicular to the axial direction of the tubular member 12, the end faces can be formed without cutting both ends.

[0042] When the substrate 13 is wound in a spiral shape, it is possible to wind the substrates 13 so that they overlap each other (so that overlapping portions 13g between the substrates 13 are not formed) as in the present embodiment, or to wind the substrates 13 so that they do not overlap each other. The cylindrical member 12 of the present embodiment is formed by winding the strip-shaped substrate 13 in a spiral shape from the second end portion 13b toward the first end portion 13a while having overlapping portions 13g in which a part of the substrate 13 on the inner periphery side is covered by the substrate 13 on the outer periphery side. The overlapping portions 13g have a width of 0.5 mm to 5 mm, and preferably have a width of 1 mm to 3 mm. If the width of the overlapping portions 13g is smaller than four times the thickness of the substrate 13, the overlapping portions 13g, which are the welded portions, are more likely to be broken than the substrate 13 portions, and the possibility of the overlapping portions 13g being unable to withstand the expansion and contraction of the active material accompanying charge and discharge increases, so the width of the overlapping portions 13g is preferably four times or more the thickness of the substrate 13. In this embodiment, the cylindrical members 12 are arranged such that the overlapping portions 13g, 13g of the cylindrical members 12, 12 adjacent to each other in the X-axis direction do not come into contact with each other.

[0043] Examples of means for joining the substrates 13 include welding (e.g., ultrasonic welding) and adhesives. When the substrate 13 is wound in a spiral shape, the joint 13h between the substrates 13 is formed in a spiral shape, so that even if a part of the joint 13h is torn, the torn part is less likely to expand compared to when the substrate 13 is wound in a spiral shape, and leakage of the active material is easily reduced. In addition, when the substrate 13 is wound in a spiral shape, the length of the tubular member 12 can be easily adjusted by adjusting the number of turns of the substrate 13 of a certain width.

[0044] An example of the winding angle θ with respect to the horizontal direction of the base material 13 (arrangement direction of the tubular member) is 10° to 90°. The winding angle θ is the angle of the base material 13 at the center of the X-axis direction of the tubular member 12 with respect to the horizontal direction when the tubular member 12 is viewed from the Y-axis direction. The angle range of the winding angle θ is preferably 30° to 50°, and more preferably 35° to 45°. Note that in FIG. 4 (FIG. 13), the angle of the base material 13 is depicted as being uniformly the same regardless of the position in the X-axis direction of the tubular member 12, but when viewed from the Y-axis direction, the angle actually appears to be sharper toward the end in the X-axis direction.

[0045] As shown in FIG. 4 and FIG. 5(A), the cylindrical member 12 has a proximity portion 13c which is a portion adjacent to the cylindrical member 12 adjacent in the X-axis direction. The proximity portion 13c may be a portion where the cylindrical members 12, 12 contact each other, or may be a portion adjacent to the cylindrical member 12 adjacent to each other through a gap. The gap is sufficiently small compared to the diameter of the cylindrical member 12. At least one of the multiple cylindrical members 12 is a specific cylindrical member 12A formed so that the rolled length LW of the base material 13 is 1 / 4 or less of the circumferential length of the cylindrical member 12. In this embodiment, all the cylindrical members 12 constituting the positive electrode 10 are the specific cylindrical member 12A. Hereinafter, the specific cylindrical member 12A is also simply referred to as the "cylindrical member 12". The rolled length LW of the base material 13 is preferably 1 / 6 or less of the circumferential length of the cylindrical member 12, and more preferably 1 / 8 or less.

[0046] The "wound length LW" will be explained. The "wound length LW" means the length along the circumferential direction of the portion 13e forming the first end 13a of the tubular member 12 on the substrate end surface 13f when the tubular member 12 is viewed from the Y-axis direction so that the wound end 13d of the substrate 13 on the first end 13a side is visible as shown in Fig. 4 and Fig. 5(A). The substrate end surface 13f (colored portion) is a part of the substrate 13 that extends in the winding direction of the substrate 13 from the adjacent portion 13c to the wound end 13d on the first end 13a side as shown in Fig. 6(A).

[0047] Similarly, the rolling length LW means the length along the circumferential direction of the portion 13e forming the second end 13b of the tubular member 12 on the substrate end surface 13f when viewing the tubular member 12 from the Y-axis direction so that the rolled end 13d of the substrate 13 on the second end 13b side is visible as shown in Figures 4 and 5(B). The substrate end surface 13f (colored portion) is a part of the substrate 13 that extends in the rolling direction of the substrate 13 from the adjacent portion 13c to the rolled end 13d on the second end 13b side as shown in Figures 4 and 6(B).

[0048] In other words, the "turned length LW" means the length along the circumferential direction of the portion 13e that formed the first end 13a of the tubular member 12 on the substrate end surface 13f, which is the turned-up portion when the substrate 13 is assumed to be turned up from the winding end 13d on the first end 13a side to the adjacent portion 13c, as shown in Figures 7(A) and 8(A). Also, the "turned length LW" means the length along the circumferential direction of the portion 13e that formed the second end 13b of the tubular member 12 on the substrate end surface 13f, which is the turned-up portion when the substrate 13 is assumed to be turned up from the winding end 13d on the second end 13b side to the adjacent portion 13c, as shown in Figures 7(B) and 8(B). The substrate end surface 13f is a curved surface that follows the outer peripheral surface of the tubular member 12, and when viewed from the Y-axis direction, has an approximately triangular shape surrounded by a portion forming the proximal portion 13c, a portion forming the first end portion 13a or the second end portion 13b, and a portion forming the joint portion 13h.

[0049] Here, "viewing the tubular member 12 from the Y-axis direction so that the wound end 13d of the substrate 13 is visible" is, in this embodiment, synonymous with "viewing the tubular member 12 from one of the sides V1 and V2 in the Y-axis direction."

[0050] In the example shown in Fig. 5(A), when the tubular member 12 is viewed from the other side V2 in the Y-axis direction, the wound end 13d (substrate end surface 13f) on the first end 13a side of the substrate 13 is visible, and even when the tubular member 12 is viewed from one side V1 in the Y-axis direction, the wound end 13d (substrate end surface 13f) on the first end 13a side of the substrate 13 is not visible. In the example shown in Fig. 5(B), when the tubular member 12 is viewed from the other side V2 in the Y-axis direction, the wound end 13d (substrate end surface 13f) on the second end 13b side of the substrate 13 is visible, and even when the tubular member 12 is viewed from one side V1 in the Y-axis direction, the wound end 13d (substrate end surface 13f) on the second end 13b side of the substrate 13 is not visible.

[0051] Moreover, the winding direction of "a part of the base material 13 extending in the winding direction of the base material 13 from the adjacent portion 13c to the winding end 13d" means the direction along the longitudinal direction of the band-shaped base material 13 when the tubular member 12 is formed of the band-shaped base material 13 as shown in Fig. 3(A). Moreover, the "winding end 13d" exists on both sides of the first end 13a side and the second end 13b side as shown in Fig. 6(A), Fig. 6(B), Fig. 7(A), Fig. 7(B), Fig. 8(A) and Fig. 8(B).

[0052] In the cylindrical member 12 of this embodiment, the turned-up length LW of the base material 13 on both the first end 13a side and the second end 13b side is formed to be ¼ or less of the circumferential length of the cylindrical member 12. If the turned-up length LW of the base material 13 on at least one of the first end 13a side and the second end 13b side is formed to be ¼ or less of the circumferential length of the cylindrical member 12, the cylindrical member 12 is specified as a specific cylindrical member 12A.

[0053] As shown in Figures 5(A) and 5(B), the cylindrical member 12 has a first outer peripheral surface 12x on the V1 side and a second outer peripheral surface 12y on the V2 side in the Y-axis direction. All of the cylindrical members 12 constituting the active material holding member 11 have wound ends 13d on the first end 13a side and the second end 13b side formed on the first outer peripheral surface 12x or the second outer peripheral surface 12y. In the active material holding member 11 of this embodiment, all of the cylindrical members 12 constituting the active material holding member 11 have wound ends 13d on the first end 13a side and the second end 13b side formed on the second outer peripheral surface 12y.

[0054] 2, the active material holding member 11 is sandwiched between separators 30, 30 in the Y-axis direction. A plurality of tubular members 12 constituting the active material holding member 11 are arranged in contact with the separator 30. The electrode group 110 is housed in a battery case 120 having a relatively narrow space, so that the active material holding member 11 is sandwiched in a state in which it is pressed by the separators 30.

[0055] The substrate 13 forming the cylindrical member 12 may be formed to include nonwoven fabric, woven fabric, etc., and is formed to include nonwoven fabric, for example. The substrate 13 can contain a resin material. Examples of the resin material include polyester (e.g., polyalkylene terephthalate such as polyethylene terephthalate), polyolefin (polyethylene, polypropylene, etc.), polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride, polycarbonate, etc. The substrate can contain, for example, polyester, and can include nonwoven fabric containing polyester.

[0056] When the substrate 13 includes fibers, the fibers may be oriented. For example, the nonwoven fabric may have an MD direction (machine direction) in the manufacture of the nonwoven fabric and a CD direction (width direction) perpendicular to the MD direction. Since fibers tend to be oriented in the MD direction, the mechanical strength tends to be higher in the MD direction than in the CD direction. Therefore, a resin sheet with high mechanical strength in the CD direction is also a sheet with high mechanical strength in the direction (CD direction) where the mechanical strength is relatively low. When the substrate 13 includes a nonwoven fabric, it is preferable that the MD and CD directions of the nonwoven fabric are inclined with respect to the axial direction (Z-axis direction) of the cylindrical member 12 in at least one of the active material holding members 11, from the viewpoint of easily suppressing the influence of the mechanical strength caused by the fiber orientation and thus easily suppressing the leakage of the active material.

[0057] The inclination angle of the MD or CD direction with respect to the axial direction of the cylindrical member 12 is preferably in the following range from the viewpoint of easily suppressing the influence of mechanical strength caused by fiber orientation and thus easily suppressing leakage of active material. The inclination angle is preferably more than 0°, more preferably 10° or more, even more preferably 20° or more, particularly preferably 30° or more, extremely preferably 40° or more, and extremely preferably 43° or more. The inclination angle is preferably less than 90°, more preferably 80° or less, even more preferably 70° or less, particularly preferably 60° or less, extremely preferably 50° or less, and extremely preferably 47° or less. From these viewpoints, the inclination angle is preferably more than 0° and less than 90°, more preferably 10° to 80°, and even more preferably 43° to 47°. It is presumed that when the inclination angle is 45°, the influence of mechanical strength caused by fiber orientation is most easily suppressed.

[0058] The substrate 13 may be a porous body having pores. The substrate 13 preferably has a portion having an average pore diameter in the following range. The average pore diameter of the substrate 13 is preferably 60 μm or less, more preferably 50 μm or less, even more preferably 45 μm or less, and particularly preferably 40 μm or less, from the viewpoint of easily suppressing the outflow of the electrode material. The average pore diameter of the substrate 13 is preferably more than 2 μm, more preferably 5 μm or more, even more preferably 10 μm or more, particularly preferably 20 μm or more, extremely preferably 30 μm or more, and very preferably 35 μm or more, from the viewpoint of easily reducing the electrical resistance. From these viewpoints, the average pore diameter of the substrate 13 is preferably more than 2 μm and 60 μm or less. The average pore diameter can be measured by a pore distribution measuring device (for example, AUTO PORE IV 9520 manufactured by Shimadzu Corporation).

[0059] At least one cylindrical member 12 in the active material holding member 11 may have a portion having a thickness (also referred to as the thickness or the thickness of the wall portion constituting the cylindrical member 12; the same applies below) in the following range. The thickness of the cylindrical member 12 may be in the following range. The thickness of the cylindrical member 12 may be 0.05 mm or more, 0.1 mm or more, or 0.2 mm or more. The thickness of the cylindrical member 12 may be 1 mm or less, 0.8 mm or less, 0.6 mm or less, or 0.4 mm or less. From these viewpoints, the thickness of the cylindrical member 12 may be 0.05 mm to 1 mm.

[0060] The length of at least one cylindrical member 12 in the active material holding member 11 may be in the following ranges. The length of the cylindrical member 12 may be 50 mm or more, 100 mm or more, 120 mm or more, 160 mm or more, or 200 mm or more. The length of the cylindrical member 12 may be 800 mm or less, 750 mm or less, 700 mm or less, 650 mm or less, 600 mm or less, or 580 mm or less. From these viewpoints, the length of the cylindrical member 12 may be 50 mm to 800 mm.

[0061] The core metal 14 is inserted into each of the cylindrical members 12. The core metal 14 is formed in a rod shape. The core metal 14 extends along the Z-axis direction inside the cylindrical members 12. The core metal 14 can be obtained by, for example, casting (pressure casting). The constituent material of the core metal 14 may be any conductive material, and examples thereof include lead alloys such as lead-calcium-tin alloys and lead-antimony-arsenic alloys. The lead alloy may contain selenium, silver, bismuth, etc. The length of the core metal 14 is, for example, 45 mm to 805 mm.

[0062] The positive electrode material 16 is filled inside the cylindrical member 12. The positive electrode material 16 includes an active material. The active material includes both the active material after chemical conversion and the raw material of the active material before chemical conversion. The positive electrode material 16 here includes the active material after chemical conversion. The positive electrode material 16 after chemical conversion can be obtained, for example, by chemical conversion of the unchemical positive electrode material 16 containing the raw material of the positive electrode active material. The positive electrode material 16 after chemical conversion can be obtained, for example, by aging and drying a positive electrode material paste containing the raw material of the positive electrode active material to obtain the unchemical positive electrode material 16, and then chemical conversion of the unchemical positive electrode material 16. Examples of the raw material of the positive electrode active material include lead powder, red lead, and the like. Examples of the positive electrode active material in the positive electrode material 16 after chemical conversion include lead dioxide, and the like. The positive electrode material 16 may further contain an additive as necessary. Examples of the additive of the positive electrode material 16 include short fibers for reinforcement, and the like. Examples of reinforcing short fibers include acrylic fibers, polyethylene fibers, polypropylene fibers, polyethylene terephthalate fibers (PET fibers), and the like.

[0063] The cylindrical member 12, the metal core 14 and the positive electrode material 16 constitute a cylindrical electrode. The cylindrical electrode of the positive electrode 10 is electrically connected to the electrode post 140a via the connecting portion 18a, the lug portion 18b and the connecting member 130a.

[0064] 1, 9(A) and 9(B), the lower connecting seat 51 is attached to a first end 13a, which is the lower end of the multiple cylindrical members 12 that constitute the active material holding member 11. The lower connecting seat 51 seals the lower ends of the multiple cylindrical members 12. The lower connecting seat 51 is fitted into the lower ends of the multiple cylindrical members 12.

[0065] In addition, the first end 13a, which is the lower end of the cylindrical member 12, may be welded by melting a resin, which will be described in detail later when forming the lower linking seat 51, as shown in FIG. 10. In addition, the cylindrical member 12 may be integrally formed when the lower linking seat 51 is injection molded. In addition, the part formed by melting the lower linking seat 51 or the part formed integrally with the cylindrical member 12 forms a curling prevention part 55 that fixes the base materials 13 to each other from the outer peripheral surface side of the cylindrical member 12 so as to straddle the joint part 13h between the base material 13 on the inner peripheral side and the base material 13 on the outer peripheral side at the first end 13a of the cylindrical member 12. The curling prevention part 55 completely covers the base material end surface 13f on the first end 13a side from the radial outside.

[0066] As shown in Figures 1, 9(A) and 9(B), the lower linking seat 51 comprises a plurality of main body portions 52, a protruding piece (inserted portion) 53 provided on each of the plurality of main body portions 52, and a connecting portion 54 connecting the plurality of main body portions 52.

[0067] A portion of the main body 52 is fitted (inserted and fitted) into the first end 13a, which is the lower end of the tubular member 12. The main body 52 is formed in a bottomed cylindrical shape whose axial direction is the Z-axis direction and opens upward. The lower end 14a of the core 14 is fitted into the tubular hole 52h of the main body 52. ​​This allows the core 14 to be held in the tubular hole 52h. The tubular hole 52h of the main body 52 includes a circular hole. The circular hole of the tubular hole 52h here is a hole whose cross section along the XY plane has a perfect circular shape. A plurality of main bodies 52 are provided corresponding to the plurality of tubular members 12. The plurality of main bodies 52 are arranged in parallel with a predetermined gap therebetween along the X-axis direction.

[0068] Four protruding pieces 53 are provided on each main body 52 so as to protrude along the Z-axis direction. The protruding pieces 53 here are provided at four equally spaced positions (four equally spaced positions) around the axial direction of each main body 52 when viewed from above. The protruding pieces 53 are formed in a plate shape extending along the radial direction of the main body 52 and along the Z-axis direction. The protruding pieces 53 are disposed inside the cylindrical member 12. The upper part of the protruding piece 53 forms a pointed part that points upward. The tip of the upper part of the protruding piece 53 is rounded and chamfered. The connecting portion 54 connects the multiple main body parts 52 in a state where they are arranged in parallel with a predetermined gap therebetween along the Y-axis direction. The connecting portion 54 extends along the Y-axis direction. The connecting portion 54 is provided so as to be integral (inseparably integrated) with the main body 52.

[0069] The lower linking seat 51 is formed of, for example, a material having acid resistance. Examples of the material of the lower linking seat 51 include resins such as polyolefin (polypropylene, polyethylene, etc.), polyethylene terephthalate (PET), polystyrene (PS), polyvinylidene fluoride (PVDF), and polycarbonate (PC). From the viewpoint of easily improving cycle characteristics, the lower linking seat 51 preferably contains a thermoplastic resin, more preferably contains a polyolefin, and further preferably contains polypropylene. From the viewpoint of easily improving cycle characteristics, when the cylindrical member 12 contains a polyolefin, the lower linking seat 51 preferably contains these materials. The lower linking seat 51 may be formed of the same material as the cylindrical member 12, or may be formed of a material different from the cylindrical member 12. The material of the lower linking seat 51 is not particularly limited.

[0070] 11, the curled height LH of the substrate end surface 13f in the tubular member 12 is equal to or less than the length L in the Z-axis direction of the protruding piece 53 that is a part of the lower linking seat 51 inserted in the tubular member 12. In this embodiment, the curled height LH of the substrate end surface 13f is equal to or less than the length L in the Z-axis direction of the protruding piece 53 inserted in the tubular member 12.

[0071] The "turned-up height LH" means the length in the Z-axis direction of the adjacent portion 13c of the substrate end surface 13f described above. In other words, the "turned-up height LH" means the length along the Z-axis direction of the portion 13i that formed the adjacent portion 13c of the tubular member 12 on the substrate end surface 13f, which is the turned-up portion when the substrate 13 is assumed to be turned up from the winding end portions 13d on the first end portion 13a side and the second end portion 13b side to the adjacent portion 13c, as shown in Figures 7(A) and 8(A).

[0072] 11, the length L in the Z-axis direction of the protruding piece 53 inserted in the tubular member 12 is 3 mm to 15 mm, and preferably 5 mm to 13 mm. An example of the turned-up height LH is 2.5 mm to 13 mm. Furthermore, the difference between the length L in the Z-axis direction of the protruding piece 53 inserted in the tubular member 12 and the turned-up height LH is 1 mm to 13 mm, and preferably 11 mm to 13 mm.

[0073] In order to confirm how far the lower linking seat 51 (projection piece 53) is inserted into the cylindrical member 12 in the Z-axis direction after the lead-acid battery 100 has been used, there is a method of cutting the cylindrical member 12 so that a cross section of the cylindrical member 12 can be confirmed as shown in Fig. 1, and visually confirming whether the cut surface includes the lower linking seat 51. If it is not possible to distinguish between the members visually, the presence or absence of the lower linking seat 51 may be confirmed by performing a composition analysis of a sample, for example.

[0074] 11, lower end 14a of core 14 is provided to be located lower than upper end 53a of protruding piece 53 in the Z-axis direction. The length of the portion where core 14 and protruding piece 53 overlap in the Z-axis direction is 2 mm to 15 mm, and preferably 5 mm to 13 mm.

[0075] As shown in FIG. 1 and FIG. 12, the upper linking seat 61 is attached to the second end 13b, which is the upper end of the multiple cylindrical members 12 constituting the active material holding member 11. The upper linking seat 61 is fixed to the upper end of the cylindrical member 12 by welding. In the welding, the boundary portion between the upper linking seat 61, the cylindrical member 12, and the upper linking seat 61 may be integrated. The welding can be realized by heating, ultrasonic irradiation, laser irradiation, etc. The upper linking seat 61 may be fixed to the upper end of the multiple cylindrical members 12 by a thermosetting adhesive or the like. In addition, in the second end 13b, as in the first end 13a, a roll-up prevention part 55 may be provided so as to straddle the joint part 13h between the inner peripheral side base material 13 and the outer peripheral side base material 13 and to fix the base materials 13 to each other.

[0076] The upper linking seat 61 includes a bottomed box-shaped base 62 having an elongated opening 62a, and a plurality of tubular portions 63 provided on a bottom surface 62b of the base 62. The upper linking seat 61 constitutes a seat member.

[0077] The base 62 abuts against the upper end of the tubular member 12. A predetermined number of tubular portions 63 are provided corresponding to the number of the plurality of tubular members 12. The tubular portions 63 are formed in a cylindrical shape having an outer diameter corresponding to the inner diameter of the tubular members 12. The tubular portions 63 are inserted so as to communicate with each of the upper ends of the plurality of tubular members 12. The tubular portions 63 have tubular holes 63a that communicate with the interior of the base 62.

[0078] The upper linking seat 61 is formed of a material including, for example, polystyrene. The material of the upper linking seat 61 is not particularly limited. For example, examples of the material of the upper linking seat 61 include materials having acid resistance. Examples of the material of the upper linking seat 61 include resins such as polyolefin (polypropylene, polyethylene, etc.), polyethylene terephthalate (PET), polystyrene (PS), polyvinylidene fluoride (PVDF), and polycarbonate (PC).

[0079] The negative electrode 20 is, for example, a plate-shaped electrode. The negative electrode 20 is, for example, a paste-type negative electrode plate. The negative electrode 20 is electrically connected to the electrode column 140b via a connecting member 130b. The negative electrode 20 has a negative electrode current collector and a negative electrode material that is an electrode material held by the negative electrode current collector. A plate-shaped current collector can be used as the negative electrode current collector. The compositions of the negative electrode current collector and the core metal 14 of the positive electrode 10 may be the same or different from each other. The negative electrode material contains an active material. The negative electrode material here contains the active material after chemical conversion.

[0080] The negative electrode material after chemical formation can be obtained, for example, by chemically forming an unformed negative electrode material containing a raw material of the negative electrode active material. The negative electrode material after chemical formation can be obtained, for example, by aging and drying a negative electrode material paste containing a raw material of the negative electrode active material to obtain an unformed negative electrode material, and then chemically forming the unformed negative electrode material. Examples of raw materials of the negative electrode active material include lead powder and the like. Examples of the negative electrode active material in the negative electrode material after chemical formation include porous spongy lead and the like. The negative electrode material can further contain additives as necessary. Examples of additives for the negative electrode material include barium sulfate, reinforcing short fibers, carbon materials (carbonaceous conductive materials), resins having at least one selected from the group consisting of sulfonic groups and sulfonic acid groups (resins having sulfonic groups and / or sulfonic acid groups), and the like. As the reinforcing short fibers, reinforcing short fibers similar to those of the positive electrode material can be used.

[0081] Examples of carbon materials include carbon black, graphite, and the like. Examples of carbon black include furnace black (Ketjen Black (registered trademark), etc.), channel black, acetylene black, thermal black, and the like. Examples of resins having a sulfonic group and / or a sulfonate group include lignin sulfonic acid, lignin sulfonate salts, condensates of phenols, aminoarylsulfonic acid, and formaldehyde, and the like. Examples of lignin sulfonate salts include alkali metal salts of lignin sulfonic acid, and the like. Examples of phenols include bisphenol-based compounds such as bisphenol, and the like. Examples of aminoarylsulfonic acids include aminobenzenesulfonic acid, aminonaphthalenesulfonic acid, and the like.

[0082] The support member 160 is disposed on the bottom surface of the battery case 120 and supports the lower connecting seat 51. The support member 160 has a plurality of ridges 160a that protrude in the Z-axis direction. The ridges 160a are provided on the bottom surface of the battery case 120. The ridges 160a extend in the X-axis direction. The ridges 160a are aligned in the Y-axis direction. The ridges 160a abut against the lower connecting seat 51 (see FIG. 1). That is, the support member 160 supports the portion of the lower connecting seat 51 on the bottom side of the battery case 120 by the ridges 160a. It is sufficient that the ridges 160a are in contact with the positive electrode 10, and they do not need to be in contact with the negative electrode 20.

[0083] The effect of the lead-acid battery 100 including the active material holding member 11 of the above embodiment will be described. The cylindrical member 12 formed by winding the base material 13 at least once has a tendency that the base material 13 is easily rolled up (easily peeled off) from the winding end 13d due to external stress acting on the outer circumferential surface (first outer circumferential surface 12x or second outer circumferential surface 12y) of the cylindrical member 12 at at least one of the first end 13a and the second end 13b, which are the ends in the extension direction. As shown in Fig. 5(A) and Fig. 5(B), the active material holding member 11 of the above embodiment is arranged in the X-axis direction, and even if the base material 13 is rolled up in the opposite direction to the winding direction, there is little possibility that the adjacent cylindrical members 12 will be rolled up beyond the adjacent portions 13c where they are close to each other.

[0084] 5(A) and 5(B), at least one of the multiple cylindrical members 12 included in the active material holding member 11 of the above embodiment is formed so that the rolled length LW of the substrate 13 is equal to or less than ¼ of the circumferential length of the cylindrical member 12 (formed as a specific cylindrical member 12A). Therefore, even if the substrate 13 rolls up from the wound end 13d, the amount of rolled up substrate 13 is kept short, and leakage of the positive electrode material 16 can be reduced.

[0085] 10, a modified example has been described in which the first end 13a is provided with a roll-up prevention part 55 that straddles the joint part 13h between the inner circumferential side base material 13 and the outer circumferential side base material 13 and fixes the base materials 13 to each other. In this case, the roll-up prevention part 55 fixes the inner circumferential side base material 13 and the outer circumferential side base material 13 integrally at the first end 13a of the tubular member 12, so that the roll-up of the wound end 13d can be more reliably prevented.

[0086] In the above embodiment, as shown in FIG. 4, the second cylindrical member 12L in which the winding end 13d peels off is wound clockwise and the first cylindrical member 12R in which the winding end 13d peels off are mixed, so even if the direction in which the external stress acts and the direction in which the base material 13 of the first cylindrical member 12R rolls up are the same, the direction in which the external stress acts and the direction in which the base material 13 of the second cylindrical member 12L rolls up are opposite to each other, so the winding end 13d of the second cylindrical member 12L will not roll up. That is, by providing two types of cylindrical members 12, the first cylindrical member 12R in which the base material 13 is wound clockwise and the second cylindrical member 12L in which the base material 13 is wound counterclockwise, the risk of the winding end 13d rolling up due to the external stress acting in one direction is dispersed. As a result, the leakage of the positive electrode material 16 can be reduced.

[0087] Furthermore, if all of the multiple tubular members 12 constituting the active material holding member 11 are unified as tubular members 12 in which the base material 13 is wound clockwise or counterclockwise when viewed from the second end 13b side in the Z-axis direction, there will be only one type of tubular member 12, and procurement costs can be reduced.

[0088] As shown in FIG. 3(A), the cylindrical member 12 of the above embodiment is formed by spirally winding the strip-shaped base material 13 from the second end 13b to the first end 13a while having an overlapping portion 13g in which a part of the inner peripheral side base material 13 is covered by the outer peripheral side base material 13. In such a cylindrical member 12, since the inner peripheral side base material 13 is partially covered by the outer peripheral side base material 13, the wound end 13d on the second end 13b side can be made to be less likely to roll up than the wound end 13d on the first end 13a side. That is, one of the wound ends 13d formed at both ends of the cylindrical member 12 can be structurally made to be less likely to roll up, so that leakage of the positive electrode material 16 can be reduced. Furthermore, in the cylindrical member 12 of the above embodiment, leakage of the positive electrode material 16 from the joint portion 13h of the strip-shaped base materials 13 adjacent to each other in the extension direction can be reduced.

[0089] The overlapping portions 13g of the cylindrical members 12 protrude in the radial direction from the outer circumferential surface of the cylindrical members 12, and when the overlapping portions 13g of adjacent cylindrical members 12 overlap or intersect with each other, the overlapping portions 13g come into close contact with each other, hindering the flow of the electrolyte 40 or the gas generated in the battery container 120. In the active material holding member 11 of the above embodiment, as shown in Fig. 4, the cylindrical members 12 are arranged so that the overlapping portions 13g of the cylindrical members 12 adjacent to each other in the X-axis direction do not come into contact with each other. Therefore, there are no portions where the overlapping portions 13g come into close contact with each other, and an environment that is excellent in the flow of the electrolyte 140 or the gas can be provided.

[0090] In the cylindrical member 12 of the above embodiment, the rolled-up height LH of the base material 13 is formed to be equal to or less than the length in the Z-axis direction of the lower connecting seat 51 (projecting piece 53) inserted in the cylindrical member 12, as shown in Fig. 11. Even if the base material 13 rolls up from the winding end 13d of the cylindrical member 12, the lower connecting seat 51 is inserted in the cylindrical member 12 of the above embodiment, so that the positive electrode material 16 is prevented from falling to the first end 13a of the cylindrical member 12 and the amount of the positive electrode material 16 filled in the internal space of the cylindrical member 12 is reduced by the amount of the lower connecting seat 51 inserted. In this configuration, even if the base material 13 rolls up from the winding end 13d to the adjacent portion 13c, leakage of the positive electrode material 16 from the rolled-up portion can be reduced.

[0091] In the active material holding member 11 of the above embodiment, as shown in Figures 5(A) and 5(B), the wound ends 13d of all of the tubular members 12 are uniformly positioned on the second outer peripheral surface 12y side, thereby improving workability during assembly.

[0092] Although one embodiment has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit and scope of the invention.

[0093] <Variation 1> The active material holding member 11 of the lead-acid battery 100 of the above embodiment has been described by taking an example in which the cylindrical member 12 is composed of two types of members, a first cylindrical member 12R formed by winding the substrate 13 clockwise when viewed from the second end 13b side, and a second cylindrical member 12L formed by winding the substrate 13 counterclockwise, but is not limited thereto. As shown in Fig. 13 and Fig. 14(A), the active material holding member 11 may be composed of one type of cylindrical member 12, the first cylindrical member 12R formed by winding the substrate 13 clockwise, or as shown in Fig. 14(B), it may be composed of one type of cylindrical member 12, the second cylindrical member 12L formed by winding the substrate 13 counterclockwise. In the active material holding member 11 according to the first modification, the type of cylindrical member 12 is one type, so that procurement costs can be reduced.

[0094] <Variation 2> In the lead-acid battery 100 of the above embodiment, an example was described in which all of the cylindrical members 12 constituting the active material holding member 11 have the wound ends 13d on the first end 13a side and the second end 13b side formed on the first outer peripheral surface 12x or the second outer peripheral surface 12y, but this is not limited thereto. For example, as shown in Figures 15(A) and 15(B), the active material holding member 11 may be composed of a cylindrical member 12 having the wound ends 13d on the first end 13a side and the second end 13b side formed on the first outer peripheral surface 12x, and a cylindrical member 12 having the wound ends 13d on the first end 13a side and the second end 13b side formed on the second outer peripheral surface 12y.

[0095] The active material holding member 11 shown in Fig. 15(A) is composed of one type of cylindrical member 12, that is, a first cylindrical member 12R formed by winding the substrate 13 clockwise. The active material holding member 11 shown in Fig. 15(B) is composed of two types of cylindrical members 12, that is, a first cylindrical member 12R formed by winding the substrate 13 clockwise, and a second cylindrical member 12L formed by winding the substrate 13 counterclockwise.

[0096] In the active material holding member 11 according to the second modification, the position of the wound end 13d in the cylindrical member 12 is distributed between the first outer peripheral surface 12x and the second outer peripheral surface 12y, so that the risk of the wound end 13d being rolled up by an external stress acting in one direction is dispersed. As a result, leakage of the positive electrode material 16 can be reduced. By configuring the active material holding member 11 shown in FIG. 15(B), the winding direction of the substrate 13 and the arrangement position of the wound end 13d can be further dispersed. In this configuration, the risk of the wound end 13d being rolled up by an external stress acting in one direction is further dispersed, so that leakage of the positive electrode material 16 can be more effectively reduced.

[0097] <Variation 3> In the above embodiment, the examples were mainly described in which the winding length LW of both the first end 13a side and the second end 13b side is formed to be 1 / 4 or less of the circumferential length of the tubular member 12, but in particular, when using a tubular member 12 formed by spirally winding the strip-shaped base material 13 from the second end 13b to the first end 13a while having an overlapping portion 13g as shown in Fig. 7(A) and Fig. 8(A), only the winding length LW of the winding end 13d on the first end 13a side, which is the winding end side, may be formed to be 1 / 4 or less of the circumferential length of the tubular member 12. In other words, a specific tubular member 12A in which only the winding length LW of the winding end 13d on the first end 13a side is 1 / 4 or less of the circumferential length of the tubular member 12 may be used.

[0098] In the cylindrical member 12 having the overlapping portion 13g, the wound end 13d on the second end 13b side, which is the winding start side, is pressed from the radial outside by the base material 13 that is wound later, and therefore is less likely to be rolled up than the wound end 13d on the first end 13a side, which is the winding end side. In consideration of this aspect, the lead-acid battery 100 may be configured as follows. That is, the lead-acid battery 100 according to the third modification may be configured to include a specific cylindrical member 12A that is arranged so that the wound end 13d on the first end 13a side, which is the winding end side, is located vertically downward in the battery case 120 (sealed by the lower connecting seat 51), and is formed so that only the wound length LW of the wound end 13d on the first end 13a side is ¼ or less of the circumferential length of the cylindrical member 12.

[0099] The active material holding member 11 and the positive electrode 10 having the active material holding member 11 are preferably used in a flooded lead-acid battery, and the lead-acid battery 100 is preferably a flooded lead-acid battery. In general, in a flooded lead-acid battery, the entire electrode group 110 tends to be immersed in the electrolyte 40, and the amount of electrolyte 40 tends to be larger than in a valve-regulated lead-acid battery or the like. In this case, the discharge capacity is less likely to be regulated by the amount of electrolyte, so that the discharge capacity tends to be large. However, in a flooded lead-acid battery, the concentration of sulfuric acid in the region below the electrode group 110 increases due to stratification of the electrolyte 40, and the substrate 13 below the cylindrical member 12 in the electrode group 110 is likely to deteriorate.

[0100] Furthermore, in flooded lead-acid batteries, deterioration over time (including deterioration due to charge / discharge cycles) progresses, causing the positive electrode material 16 to turn muddy, making the positive electrode material 16 more susceptible to leakage. If the base material 13 of the tubular member 12 is rolled up in this state, the positive electrode material 16 will leak significantly. On the other hand, in the active material retention member 11 according to each of the above-mentioned embodiments and their modified embodiments, the base material 13 is less likely to roll up from the wound end 13d, making it possible to utilize the advantages of flooded lead-acid batteries while suppressing leakage of the positive electrode material 16.

[0101] The lead-acid battery 100 according to the third modification can effectively reduce leakage of the positive electrode material 16 since it is possible to reduce leakage of the positive electrode material 16 at the vertically lower end of the tubular member 12 where the positive electrode material 16 is likely to break down into fine particles.

[0102] <Variation 4> Considering the aspects described in Modification 3, the lead-acid battery 100 may be configured to include a specific cylindrical member 12A in which the wound end 13d on the first end 13a side, which is the winding end side, is arranged to be located vertically upward in the battery case 120 (sealed by the upper connecting seat 61), and only the winding length LW of the wound end 13d on the first end 13a side is ¼ or less of the circumferential length of the cylindrical member 12. The lead-acid battery 100 according to Modification 4 is arranged so that the wound end 13d on the first end 13a side, which is easily wound, is upward, so that leakage of the positive electrode material 16 can be reduced.

[0103] <Variation 5> As a modified example of the above embodiment, the lead-acid battery 100 including the curling prevention part 55 has been described as an example, but even if the lead-acid battery 100 does not include the curling prevention part 55, the separator (holding member) 30 may be disposed so as to contact a part of the substrate end surface 13f of the cylindrical member 12. With this configuration, the substrate end surface 13f including the winding end 13d is held down by the separator 30, so that the substrate 13 can be prevented from curling up from the winding end 13d.

[0104] <Variation 6> In the above embodiment and modified example, the first end 13a, which is the lower end of the cylindrical member 12, and the lower connecting seat 51 are fitted together. In addition to this configuration, the first end 13a, which is the lower end of the cylindrical member 12, and the lower connecting seat 51 may be fixed by an adhesive made of a thermoplastic resin (for example, polystyrene, PP, PE, etc.). The part where the lower connecting seat 51 is fixed to the first end 13a of the plurality of cylindrical members 12 by an adhesive made of a thermoplastic resin forms a roll-up prevention part 55 at the first end 13a of the cylindrical member 12 so as to straddle the joint part 13h between the inner peripheral side base material 13 and the outer peripheral side base material 13 and to fix the base materials 13 to each other from the outer peripheral surface side of the cylindrical member 12. The roll-up prevention part 55 completely covers the base material end surface 13f on the first end 13a side from the radial outside. In this case too, the roll-up prevention portion 55 integrally fixes the inner circumferential side substrate 13 and the outer circumferential side substrate 13 at the first end portion 13a of the tubular member 12, thereby more reliably preventing the wound end portion 13d from rolling up.

[0105] <Other Modifications> The above embodiment and modified examples of the tubular member 12 have been described using examples in which the cross section of the outer shape when viewed from the extension direction is formed to be circular, but as long as it is tubular, it may be elliptical, rectangular, diamond-shaped, square, or the like.

[0106] The active material holding member 11, the electrode group 110, and the lead-acid battery 100 according to one embodiment of the present invention can be used, for example, in an electric vehicle. Examples of the electric vehicle include a forklift and a golf cart.

[0107] In the lead-acid battery 100 for electric vehicles, the height of the positive electrode 10 and the negative electrode 20 is likely to be designed to be large in the height direction of the lead-acid battery 100. Therefore, since sulfuric acid in the electrolyte 40 is likely to settle downward, maintenance to prevent stratification is important. Therefore, gassing may be performed by applying overcharge at the end of charging to stir the electrolyte 40. In this case, if the base material 13 of the cylindrical member 12 is rolled up and the positive electrode material 16 leaks, the positive electrode material 16 is likely to fly up and accumulate on the electrode (e.g., the negative electrode 20) due to this gassing, which may cause a short circuit. The lead-acid battery 100 according to the above embodiment and modified example can suppress leakage of the positive electrode material 16, and therefore can suppress short circuits caused by gassing, and therefore can be suitably used in electric vehicles.

[0108] In one aspect of the present invention, the respective configurations of the above-described embodiment and the above-described modified examples may be appropriately combined. One aspect of the present invention can be modified in various ways without departing from the gist of the invention. [Explanation of symbols]

[0109] 10...positive electrode, 11...active material holding member, 12...cylindrical member, 12A...specific cylindrical member, 12L...second cylindrical member, 12R...first cylindrical member, 12x...first outer peripheral surface, 12y...second outer peripheral surface, 13...substrate, 13a...first end, 13b...second end, 13c...adjacent portion, 13d...wound end, 13f...substrate end surface, 13g...overlapping portion, 13h...joint portion, 16...positive electrode material (active material), 20...negative electrode, 30...separator (holding member), 51...lower seat (first sealing portion), 53...protruding piece (inserted portion), 61...upper seat (second sealing portion), 100...lead-acid battery, 110...electrode group, 120...battery case.

Claims

1. an active material holding member including a plurality of cylindrical members extending in a first direction between a first end and a second end and formed by winding a base material at least once, the cylindrical members being arranged in a second direction perpendicular to the first direction and having adjacent portions which are adjacent to adjacent cylindrical members in the second direction, and at least one of the plurality of cylindrical members being a specific cylindrical member formed such that the rolled length of the base material is ¼ or less of the circumferential length of the cylindrical members; a first sealing portion that seals the first ends of the plurality of tubular members; a second sealing portion that seals the second ends of the plurality of tubular members; and an active material filled in the cylindrical member, The rolled length is a length along a circumferential direction of a portion of the substrate that forms the first end or the second end of the substrate on the substrate end surface when the substrate is viewed from a third direction perpendicular to both the first direction and the second direction so that the rolled end of the substrate is visible, and a portion of the substrate that extends in the rolled direction of the substrate from the adjacent portion to the rolled end is defined as a substrate end surface, a curled-up height of the base material in the tubular member is equal to or less than a length in the first direction of an inserted portion in which the first sealing portion is inserted into the tubular member, The curled height is the length in the first direction at the adjacent portion of the substrate end surface.

2. an active material holding member including a plurality of cylindrical members extending in a first direction between a first end and a second end and formed by winding a base material at least once, the cylindrical members being arranged in a second direction perpendicular to the first direction and having adjacent portions which are adjacent to adjacent cylindrical members in the second direction, and at least one of the plurality of cylindrical members being a specific cylindrical member formed such that the rolled length of the base material is ¼ or less of the circumferential length of the cylindrical members; a first sealing portion that seals the first ends of the plurality of tubular members; a second sealing portion that seals the second ends of the plurality of tubular members; and an active material filled in the cylindrical member, The turned-up length is a length along the circumferential direction of a portion that formed the first end portion or the second end portion on the substrate end surface, which is a turned-up portion when the substrate is assumed to be turned up from the turned-up end portion to the adjacent portion, when the cylindrical member is viewed from a third direction perpendicular to both the first direction and the second direction so that the turned-up end portion of the substrate is visible, a curled-up height of the base material in the tubular member is equal to or less than a length in the first direction of an inserted portion in which the first sealing portion is inserted into the tubular member, The curled height is the length in the first direction at the adjacent portion of the substrate end surface.

3. The electrode according to claim 1 or 2, wherein the cylindrical member is formed by spirally winding the strip-shaped base material.

4. The electrode according to any one of claims 1 to 3, wherein the tubular member has a curling prevention portion at the first end or the second end, the curling prevention portion spanning the joint between the substrate on the inner circumference side and the substrate on the outer circumference side and fixing the substrates to each other, the curling prevention portion being provided on the outer circumferential surface side of the tubular member.

5. An electrode according to any one of claims 1 to 4; a battery case that houses the active material holding member.

6. A pressing member is further provided which is arranged in contact with a portion of the cylindrical member, The lead-acid battery according to claim 5 , wherein the pressing member is in contact with at least a portion of the substrate end surface of the cylindrical member.

7. A lead-acid battery as described in claim 5 or 6, wherein the electrodes are contained in the battery case so that the first sealing portion is located vertically downward within the battery case and the second sealing portion is located vertically upward within the battery case.

8. A lead-acid battery as described in claim 5 or 6, wherein the electrodes are contained in the battery case so that the first sealing portion is located vertically upward within the battery case and the second sealing portion is located vertically downward within the battery case.

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