WO2021053772A1

WO2021053772A1 - Electrode, lead storage cell, current collector, and method for manufacturing current collector

Info

Publication number: WO2021053772A1
Application number: PCT/JP2019/036640
Authority: WO
Inventors: 久喜竹内; 崇田中; 聡草野
Original assignee: 昭和電工マテリアルズ株式会社
Priority date: 2019-09-18
Filing date: 2019-09-18
Publication date: 2021-03-25
Also published as: JPWO2021053772A1

Abstract

A positive electrode 10 is provided with: a cylindrical body 12a; a core 14 that is inserted into the cylindrical body 12a and has a rod-like shape; a positive electrode material 16 that is packed into the interior of the cylindrical body 12a and that includes an active substance; and a lower seat 51 that seals a lower-end section of the cylindrical body 12a. The lower seat 51 has a cylindrical main body section 52 into which a lower-end section of the core 14 is fitted. An end surface 14a on the lower-end-section side of the core 14 has an elongated shape with a longitudinal direction. One side and the other side in the longitudinal direction of the elongated shape of the lower-end section of the core 14 are embedded in an inner surface of a cylindrical hole 52h of the main body section 52.

Description

Electrodes, lead-acid batteries, current collectors and methods for manufacturing current collectors

One aspect of the present invention relates to an electrode, a lead storage battery, a current collector, and a method for manufacturing the current collector.

Lead-acid batteries are widely used as secondary batteries for industrial or consumer use, and in particular, lead-acid batteries for electric vehicles (so-called batteries), UPS (Uninterruptible Power Supply), disaster prevention (emergency) radio, telephones, etc. There is a lot of demand for lead-acid batteries for backup.

The lead-acid battery includes an electrode group including a plurality of electrodes and an electric tank for accommodating the electrode group. The electrodes seal a tubular body, a current collector (core metal) that is inserted into the tubular body and has a rod shape, an electrode material that is filled inside the tubular body and contains an active material, and one end of the tubular body. A sealing member (lower joint) for stopping is provided (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 61-232572

In the electrode as described above, one end of the rod-shaped current collector may be fitted into the sealing member. In this case, for example, in consideration of use in various environments, it is required to improve the fitability between the sealing member and the current collector.

One aspect of the present invention is to provide an electrode and a lead storage battery capable of improving the fit between the sealing member and the current collector.

The electrodes according to one aspect of the present invention include a tubular body, a current collector inserted into the tubular body and having a rod shape, an electrode material filled inside the tubular body and containing an active material, and one end of the tubular body. It is an electrode provided with a sealing member for sealing a portion, and the sealing member has a tubular main body portion into which one end portion of the current collector is fitted, and is on the one end side side of the current collector. The end face has a long shape having a longitudinal direction, and one side and the other side of the long shape in the longitudinal direction at one end of the current collector are recessed into the inner surface of the tubular hole of the main body.

In this electrode, the end face on the one end side of the current collector has a long shape. Then, one end of the current collector has one side and the other side in the longitudinal direction of the long shape recessed into the inner surface of the tubular hole of the main body. Therefore, one end of the current collector can be firmly fitted into the tubular hole of the main body. It is possible to improve the fitability between the sealing member and the current collector.

In the electrode according to one aspect of the present invention, the tubular hole of the main body includes a circular hole, and the long shape of the current collector is an elliptical shape having a major axis larger than the diameter of the tubular hole as the circular hole, and is flat. It may be circular or elliptical. According to this configuration, one end of the current collector can be effectively fitted into the inner surface of the cylinder hole, and the fitability between the sealing member and the current collector can be effectively improved.

The electrode according to one aspect of the present invention may have a circular cross section at least at the other end of the current collector. In this case, even if the current collector is corroded, it is difficult to form a locally thinned portion at at least the other end of the current collector. Therefore, it is possible to suppress breakage of the current collector. Further, in this case, the active material is likely to be used evenly in the vicinity of at least the other end of the current collector inside the tubular body. Therefore, it is possible to improve the current collecting property.

The electrode according to one aspect of the present invention may have a cylindrical body. In this case, since the active material is easily used evenly inside the tubular body, it is possible to improve the current collecting property.

The electrode according to one aspect of the present invention is one side, the other side, or both sides of the long shape of the current collector fitted in the cylinder hole on the inner surface of the cylinder hole when viewed from the axial direction of the cylinder hole. May be provided with an overhanging portion protruding from the inner surface. In this case, the overhanging portion makes it possible to suppress the formation of a gap between the current collector and the inner surface of the tubular hole in the lateral direction.

The lead-acid battery according to one aspect of the present invention includes the above electrodes. Since the lead-acid battery is also provided with the electrodes, the above-mentioned effect that the fitability between the sealing member and the current collector can be improved can be obtained.

The current collector according to one aspect of the present invention includes a tubular body, an electrode material filled inside the tubular body and containing an active material, and a sealing member that seals one end of the tubular body. In the electrode, it is a rod-shaped current collector inserted into a tubular body, and the end face on the one end side exhibits a long shape having a longitudinal direction. With this current collector, for example, when one end is fitted into the sealing member, one end and one end in the longitudinal direction of the long shape are fitted into the sealing member. One end can be firmly fitted to the sealing member. It is possible to improve the fitability between the sealing member and the current collector.

In the current collector according to one aspect of the present invention, the elongated shape may be an oval shape, a flat circular shape, or an elliptical shape. In this case, for example, when one end of the current collector is fitted into the sealing member, the one end can be effectively fitted into the sealing member, and the sealing member and the current collector can be combined. It is possible to effectively improve the fitability.

In the current collector according to one aspect of the present invention, at least the cross section of the other end may have a circular shape. In this case, even if the current collector is corroded, it is difficult to form a locally thinned portion at at least the other end of the current collector. Therefore, it is possible to suppress breakage of the current collector. Further, in this case, the active material is likely to be used evenly in the vicinity of at least the other end of the current collector inside the tubular body. Therefore, it is possible to improve the current collecting property.

The method for manufacturing a current collector according to one aspect of the present invention is a method for manufacturing the current collector, which includes a cutting step of cutting a rod-shaped member constituting the current collector and one end of the cut rod-shaped member. A molding step of molding the end face on the side so as to exhibit an elongated shape is provided. According to the current collector manufactured by this manufacturing method, one end of the current collector can be firmly fitted to the sealing member, and the fitability between the sealing member and the current collector can be improved. It will be possible.

In the method for manufacturing a current collector according to one aspect of the present invention, in the molding step, when the rod-shaped member is cut by the cutting step, the end face on one end side of the rod-shaped member is utilized by utilizing the force required for the cutting. May be molded. In this case, a long shape on the end face of the current collector on the one end side can be easily and efficiently realized.

According to one aspect of the present invention, it is possible to provide an electrode, a lead storage battery, a current collector, and a method for manufacturing a current collector, which can improve the fitability between the sealing member and the current collector.

FIG. 1 is a cross-sectional view schematically showing a lead storage battery according to an embodiment. FIG. 2 is a partial cross-sectional view taken along the line II-II of FIG. FIG. 3 is a perspective view showing the positive electrode of FIG. FIG. 4A is a plan view showing the upper collective punishment of FIG. FIG. 4B is a front view showing the upper collective punishment of FIG. FIG. 5 is a partial cross-sectional view taken along the line VV of FIG. 4 (a). FIG. 6 is a front view showing the lower collective punishment of FIG. FIG. 7 is a partial cross-sectional view taken along the line VII-VII of FIG. FIG. 7 is a partial plan view of the lower collective punishment of FIG. FIG. 9 is a front view showing the core metal, the connecting portion, and the ear portion of the positive electrode of FIG. FIG. 10A is a diagram showing an end surface of the positive electrode of FIG. 3 on the lower end side of the core metal. FIG. 10B is a partial cross-sectional view taken along the line Xb-Xb of FIG. FIG. 10 (c) is a partial cross-sectional view taken along the line Xc-Xc of FIG. FIG. 11A is a diagram showing an end surface on the lower end side of the core metal according to the first modification. FIG. 11B is a diagram showing an end surface on the lower end side of the core metal according to the second modification. FIG. 11C is a diagram showing an end surface on the lower end side of the core metal according to the third modification. FIG. 11D is a diagram showing an end surface on the lower end side of the core metal according to the fourth modification. FIG. 11 (e) is a diagram showing an end surface on the lower end side of the core metal according to the fifth modification.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding elements are designated by the same reference numerals, and duplicate description will be omitted. The sizes of the components in each figure are conceptual, and the relative size relationships between the components are not limited to those shown in each figure.

FIG. 1 is a cross-sectional view schematically showing a lead storage battery. FIG. 2 is a partial cross-sectional view taken along the line II-II of FIG. FIG. 3 is a perspective view showing a positive electrode. In FIG. 1, positive electrodes and negative electrodes are alternately arranged via separators from the front side to the back side of the drawing. In FIG. 1, a part of the positive electrode is shown in cross section. FIG. 2 shows a laminated structure of a positive electrode, a negative electrode, and a separator when the lead storage battery is viewed from above. The terms "upper" and "lower" correspond to the upper and lower parts in the height direction of the battery case (hereinafter, the same applies). The Z direction corresponds to the height direction of the battery case, the X direction corresponds to the direction orthogonal to the Z direction, and the Y direction corresponds to the direction orthogonal to the Z direction and orthogonal to the X direction.

As shown in FIGS. 1 and 2, the lead-acid battery 100 according to the embodiment includes an electrode group 110, an electric tank 120 accommodating the electrode group 110, and connecting

members

130a and 130b connected to the electrode group 110. It includes

pole columns

140a and 140b connected to the connecting

members

130a and 130b, a liquid spout 150 for closing the liquid injection port of the electric tank 120, and a support member 160 connected to the electric tank 120.

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 electrode 10 and the negative electrode 20 are alternately arranged in the X direction via the separator 30. The space around the positive electrode 10 between the separators 30 is filled with the electrolytic solution 40. The material of the separator 30 is not particularly limited as long as it is a material that blocks the electrical connection between the positive electrode 10 and the negative electrode 20 and allows the electrolytic solution 40 to permeate. Examples of the material of the separator 30 include a mixture of microporous polyethylene, glass fiber and synthetic resin.

As shown in FIGS. 1, 2 and 3, the positive electrode 10 is, for example, a plate-shaped electrode. The positive electrode 10 includes a plurality of tubular bodies 12a, a plurality of core metal (current collector) 14, a positive electrode material (electrode material) 16, a lower collective punishment (sealing member) 51, an upper collective punishment 1, and a connecting portion. It has 12e and an ear portion 12d.

A plurality of tubular bodies 12a are arranged side by side in a row adjacent to each other along the Y direction. The plurality of tubular bodies 12a form a group of active material holding tubes (clad tubes). The active material holding tube group is also called a so-called "gauntlet". The tubular body 12a extends in the Z direction. The structure in which the plurality of tubular bodies 12a are arranged side by side may be obtained by the tubular bodies 12a which are separate bodies from each other, or may be obtained by forming a plurality of through holes between the base materials facing each other. A connecting portion such as a seam (sewn portion) may be arranged between the adjacent tubular bodies 12a.

The tubular body 12a has a cylindrical shape. The tubular body 12a may have an elliptical tubular shape, a square tubular shape (for example, a square tubular shape with rounded corners), or the like. The length of the tubular body 12a is, for example, 160 to 400 mm. The diameter of the tubular body 12a may be, for example, 5 mm or more. The diameter of the tubular body 12a may be, for example, 12 mm or less. The thickness of the tubular body 12a may be, for example, 100 μm or more. The thickness of the tubular body 12a may be, for example, 2000 μm or less.

The tubular body 12a is formed of a porous body. The tubular body 12a may be formed of, for example, a base material such as a woven fabric or a non-woven fabric. As the material of the base material, a material having acid resistance can be used. Materials for the base material include polyolefin (polypropylene, polyethylene, etc.), polyethylene terephthalate (PET), polystyrene (PS), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), polyvinylidene fluoride (PVDF), polycarbonate (PC). ) And other resins, glass fibers, silicon carbide, alumina and other inorganic materials. The tubular body 12a preferably contains a thermoplastic resin, and more preferably contains a polyolefin, from the viewpoint of easily improving the cycle characteristics.

In the tubular body 12a, the resin may be held on the base material. Examples of the resin include acrylic resin, epoxy resin, phenol resin, melamine resin, styrene resin and the like. The resin may be held on the inner or outer surface of the base material, or on the surface in the pores of the base material, or may be attached to the base material. The resin may be retained on a part of the substrate or may be retained on the entire substrate.

The core metal 14 is inserted into each tubular body 12a. The core metal 14 has a rod shape. The core metal 14 extends along the Z direction inside the tubular body 12a. The core metal 14 can be obtained by, for example, casting (pressure casting method). 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 and the like. The length of the core metal 14 is, for example, 170 to 400 mm.

The positive electrode material 16 is filled inside the tubular body 12a. The positive electrode material 16 contains an active material. The active material includes both the post-chemical active material and the raw material of the pre-chemical active material. The positive electrode material 16 here contains the active material after chemical conversion. The chemicalized positive electrode material 16 can be obtained, for example, by chemicalizing an unchemicald positive electrode material 16 containing a raw material for a 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 a raw material for a positive electrode active material to obtain an unchemicald positive electrode material 16 and then chemicalizing the unchemicald positive electrode material 16. Can be done. Examples of the raw material for the positive electrode active material include lead powder and lead tan. 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, if necessary. Examples of the additive for the positive electrode material 16 include short reinforcing fibers. Examples of the reinforcing short fibers include acrylic fibers, polyethylene fibers, polypropylene fibers, polyethylene terephthalate fibers (PET fibers) and the like.

The tubular body 12a, the core metal 14, and the positive electrode material 16 form a tubular electrode (rod-shaped electrode). The tubular electrode of the positive electrode 10 is electrically connected to the pole pillar 140a via the connecting portion 12e, the ear portion 12d, and the connecting member 130a.

The lower joint seat 51 is attached to the lower end portion of the plurality of tubular bodies 12a. The lower end portion of the tubular body 12a is an end portion (one end portion) on one end side of the tubular body 12a, in other words, the bottom end portion of the electric tank 120 in the tubular body 12a. The lower joint 51 seals the lower ends of the plurality of tubular bodies 12a. The lower joint 51 is fitted to the lower ends of the plurality of tubular bodies 12a. The lower joint 51 may be fixed to the lower ends of the plurality of tubular bodies 12a by a thermosetting adhesive or the like.

The upper joint seat 1 is attached to the upper end portion of the tubular body 12a. The upper end portion of the tubular body 12a is the end portion (the other end portion) on the other end side of the tubular body 12a, in other words, the end portion on the top side of the electric tank 120 in the tubular body 12a. The upper joint seat 1 is fixed to the upper end portion of the tubular body 12a by welding. In welding, the boundary portions of the upper joint 1 and the tubular body 12a and the upper joint 1 may be integrated. Welding can be realized by heating, ultrasonic irradiation, laser irradiation, or the like. The upper joints 1 may be fixed to the upper ends of the plurality of tubular bodies 12a by a thermosetting adhesive or the like.

As shown in FIGS. 1 and 2, 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 pole pillar 140b via the connecting member 130b. The negative electrode 20 has a negative electrode current collector and a negative electrode material which is an electrode material held by the negative electrode current collector. As the negative electrode current collector, a plate-shaped current collector can be used. The composition of the negative electrode current collector and the core metal 14 of the positive electrode 10 may be the same as each other or may be different from each other. The negative electrode material contains an active material. The negative electrode material here contains the active material after chemical conversion.

The negative electrode material after chemical conversion can be obtained, for example, by chemical conversion of an unchemicald negative electrode material containing a raw material for the negative electrode active material. The negative electrode material after chemical conversion can be obtained, for example, by aging and drying a negative electrode material paste containing a raw material for the negative electrode active material to obtain an unchemicald negative electrode material, and then chemicalizing the unchemicald negative electrode material. Examples of the raw material for 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 conversion include porous spongy lead and the like. The negative electrode material can further contain an additive if necessary. As the additive for the negative electrode material, a resin having at least one selected from the group consisting of barium sulfate, short reinforcing fibers, carbon material (carbonaceous conductive material), sulfone group and sulfonic acid base (sulfone group and / or sulfone). Resin having an acid base) and the like. As the reinforcing short fiber, the same reinforcing short fiber as the positive electrode material can be used.

Examples of carbon materials include carbon black and graphite. Examples of carbon black include furnace black (Ketjen black (registered trademark), etc.), channel black, acetylene black, thermal black, and the like. Examples of the resin having a sulfonic acid group and / or a sulfonic acid base include lignin sulfonic acid, lignin sulfonate, and a condensate of phenols, aminoaryl sulfonic acid, and formaldehyde. Examples of the lignin sulfonate include an alkali metal salt of lignin sulfonic acid. Examples of phenols include bisphenol compounds such as bisphenol. Examples of the aminoaryl sulfonic acid include aminobenzene sulfonic acid and aminonaphthalene sulfonic acid.

The support member 160 is arranged on the bottom surface of the electric tank 120 and supports the lower collective punishment 51. The support member 160 has a plurality of ridges 160a whose protruding direction is the Z direction. The ridge 160a is provided on the bottom surface of the battery case 120. The ridge 160a extends in the X direction. The ridges 160a are lined up in the Y direction. The ridge 160a abuts on the lower joint 51 (see FIG. 1). That is, the support member 160 supports the portion of the lower collective punishment 51 on the bottom surface side of the electric tank 120 by the ridges 160a. The ridge 160a may be in contact with the positive electrode 10 and may not be in contact with the negative electrode 20.

FIG. 4A is a plan view showing the upper collective punishment 1. FIG. 4B is a front view showing the upper collective punishment 1. FIG. 5 is a partial cross-sectional view taken along the line VV of FIG. 4 (a). As shown in FIGS. 4 (a), 4 (b) and 5, the upper collective punishment 1 is provided on a bottomed box-shaped base 2 having a long opening 2a and a bottom surface 2b of the base 2. Also includes a plurality of tubular portions 3.

The base 2 abuts on the upper end of the tubular body 12a. A predetermined number of tubular portions 3 are provided corresponding to the number of the plurality of tubular bodies 12a. The tubular portion 3 has a cylindrical shape having an outer diameter corresponding to the inner diameter of the tubular body 12a. The tubular portion 3 is inserted so as to communicate with each of the upper end portions of the plurality of tubular bodies 12a. The tubular portion 3 has a tubular hole 3a that communicates with the inside of the base portion 2.

The upper collective punishment 1 is formed of a material containing, for example, polystyrene. The material of the upper collective punishment 1 is not particularly limited. For example, as the material of the upper collective punishment 1, a material having acid resistance can be used. Examples of the material of the upper junction 1 include resins such as polyolefin (polypropylene, polyethylene, etc.), polyethylene terephthalate (PET), polystyrene (PS), polyvinylidene fluoride (PVDF), and polycarbonate (PC).

FIG. 6 is a front view showing the lower collective punishment 51. FIG. 7 is a partial cross-sectional view taken along the line VII-VII of FIG. FIG. 8 is a plan view showing a part of the lower collective punishment 51. The lower joint 51 fits into the ends of the plurality of tubular bodies 12a. As shown in FIGS. 6, 7 and 8, the lower collective punishment 51 connects the plurality of main bodies 52, the projecting pieces 53 provided on each of the plurality of main bodies 52, and the plurality of main bodies 52. A connecting portion 54 is provided.

A part of the main body 52 is fitted (inserted and fitted) into the lower end of the tubular body 12a. The main body 52 has a bottomed cylindrical shape that is axially oriented in the Z direction and opens upward. The lower end portion (one end portion) of the core metal 14 is fitted into the tubular hole 52h of the main body portion 52. As a result, the core metal 14 is held in the cylinder 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 having a perfect circular cross section along the XY surface. A plurality of main body portions 52 are provided corresponding to the plurality of tubular bodies 12a. The plurality of main body portions 52 are arranged in parallel with a predetermined gap along the Y direction.

Four projecting pieces 53 are provided on each main body 52 so as to project along the Z direction. The protruding pieces 53 here are provided at four equal positions (four points at equal intervals) around the axial direction in each main body 52 when viewed from above. The projecting piece 53 has a plate shape extending along the radial direction of the main body 52 and extending along the Z direction. The projecting piece 53 is arranged inside the tubular body 12a. The upper portion of the protruding piece 53 constitutes an upwardly pointed tip. The upper tip of the projecting piece 53 is roundly chamfered. The connecting portion 54 connects a plurality of main body portions 52 in a parallel state with a predetermined gap in the Y direction. The connecting portion 54 extends along the Y direction. The connecting portion 54 is provided so as to be integrally with the main body portion 52 (integral with the main body portion 52).

The lower collective punishment 51 is formed of, for example, a material having acid resistance. Examples of the material of the lower junction 51 include resins such as polyolefin (polypropylene, polyethylene, etc.), polyethylene terephthalate (PET), polystyrene (PS), polyvinylidene fluoride (PVDF), and polycarbonate (PC). The lower punishment 51 preferably contains a thermoplastic resin, more preferably a polyolefin, and even more preferably polypropylene, from the viewpoint of easily improving the cycle characteristics. From the viewpoint of easily improving the cycle characteristics, when the tubular body 12a contains polyolefin, it is preferable that the lower joint 51 contains these materials. The lower joint 51 may be formed of the same material as the tubular body 12a, or may be formed of a material different from that of the tubular body 12a. The material of the lower collective punishment 51 is not particularly limited.

FIG. 9 is a front view showing the core metal 14, the connecting portion 12e, and the ear portion 12d. As shown in FIG. 9, the connecting portion 12e connects the upper end portions (the other end portions) of the plurality of core metal 14 arranged in the Y direction. The connecting portion 12e extends in the Y direction. The connecting portion 12e is provided so as to be connected to the upper end portions of the plurality of core metal 14. The connecting portion 12e is inserted into and fitted into the base portion 2 of the upper joint 1 (see FIG. 5). The connecting portion 12e comes into contact with the bottom surface 2b of the base portion 2. One end of the ear portion 12d is connected to the connecting portion 12e. The other end of the ear portion 12d is connected to the connecting member 130a (see FIG. 1). The core metal 14, the connecting portion 12e, and the ear portion 12d are integrally formed.

The method for manufacturing the lead-acid battery 100 described above includes at least an electrode manufacturing process (electrode manufacturing method) for manufacturing the electrodes and an assembly step (assembly method) for assembling each component to obtain the lead-acid battery 100.

In the electrode manufacturing process, a positive electrode 10 is obtained. The electrode manufacturing process includes a step of forming the tubular body 12a, a step of attaching the upper connecting seat 1 to the upper end of the tubular body 12a, a step of inserting the core metal 14 into the tubular body 12a, and a positive electrode material 16. It includes a step of filling the tubular body 12a and a step of sealing the lower end portion of the tubular body 12a with a lower connecting seat 51. In the step of inserting the core metal 14 into the tubular body 12a, the core metal 14 is inserted into the lower end portion of the tubular body 12a via the tubular portion 3 of the upper connecting seat 1 in a state where the upper connecting seat 1 is attached to the upper end portion of the tubular body 12a. It is inserted into the tubular body 12a from the portion.

In the assembling step, for example, the unchemical positive electrode 10 and the unchemical negative electrode 20 are laminated via the separator 30, and the current collecting portions of electrodes having the same polarity are welded with a strap to obtain the electrode group 110. The electrode group 110 is inserted into the battery case 120 and arranged to produce an unchemical battery. Dilute sulfuric acid is put into an unchemical battery and a direct current is applied to form an electric tank. The lead storage battery 100 is obtained by adjusting the specific gravity of sulfuric acid after chemical conversion to an appropriate specific gravity. The chemical conversion treatment is not limited to being carried out after the assembly method, and may be carried out by an electrode manufacturing method (tank chemical conversion).

Next, the main parts of the positive electrode 10 according to the present embodiment will be described.

FIG. 10A is a diagram showing an end surface 14a on the lower end side of the core metal 14. FIG. 10B is a partial cross-sectional view taken along the line Xb-Xb of FIG. FIG. 10 (c) is a partial cross-sectional view taken along the line Xc-Xc of FIG. As shown in FIG. 10A, the end surface 14a on the lower end side of the core metal 14 exhibits a long shape having a longitudinal direction.

Specifically, the elongated shape of the end face 14a has the Y direction, which is the juxtaposed direction of the plurality of cores 14, as the longitudinal direction, and the X direction, which is the orthogonal direction of the juxtaposed directions, as the lateral direction. The shape. The elongated shape of the end face 14a is an elliptical shape having a major axis D2 larger than the diameter D1 (see FIG. 10C) of the tubular hole 52h as a circular hole. The long shape of the end face 14a is a shape in which the perfect circular shape is crushed in the X direction. The long shape of the end face 14a is a shape in which the perfect circular shape is distorted in the X direction.

As shown in FIG. 10B, the cross section of at least the upper end portion of the core metal 14 has a circular shape. Specifically, the cross section of the upper end portion and the central portion of the core metal 14 has a perfect circular shape. As shown in FIG. 10C, one end of the core metal 14 in the Y direction, which is the longitudinal direction, and the other side are recessed into the inner surface of the tubular hole 52h of the main body 52. In other words, both sides of the one end portion of the core metal 14 in the longitudinal direction penetrate into the inner surface of the tubular hole 52h. Further, in other words, both sides of the one end portion of the core metal 14 in the longitudinal direction are pushed into the inner surface of the tubular hole 52h so as to be deformed. One end of the core metal 14 is fitted into the tubular hole 52h by press-fitting so that both sides in the longitudinal direction are recessed into the inner surface of the tubular hole 52h. For example, one end of the core metal 14 has no gap between it and the inner surface of the tubular hole 52h in the longitudinal direction, enters the inner surface of the tubular hole 52h, and is fixed by the pressure (friction) thereof.

As shown in FIGS. 7, 8 and 10 (c), when viewed from the Z direction, the inner surface of the tubular hole 52h is in the X direction (the short direction of the elongated shape of the core metal 14 fitted in the tubular hole 52h). ), Each of the other side is provided with an overhanging portion 59 overhanging from the inner surface. The pair of overhanging portions 59 correspond to each other in the X direction. The pair of overhanging portions 59 project (protrude) in the X direction from the inner surface of the tubular hole 52h so as to approach each other when viewed from the Z direction. The overhanging portion 59 has a flat surface 59a continuous with the inner surface of the tubular hole 52h and along the YZ surface.

In the method for manufacturing the core metal 14 described above, the cutting step of cutting the end portion of the rod-shaped member constituting the core metal 14 with a cutting device and the end surface of the cut rod-shaped member on the lower end side are provided with a long shape. It is provided with a molding process for molding as described above. In the molding step, when the rod-shaped member is cut by the cutting step, the end face on the lower end side of the rod-shaped member is formed by utilizing the force required for the cutting. The molding step may be carried out after the cutting step. That is, instead of or in addition to forming the long shape of the end face at the time of cutting (at the same time as cutting), the long shape of the end face may be formed separately from the cutting. As the cutting method and the cutting device in the cutting step, various known methods and known devices can be adopted. As the molding method and the molding apparatus in the molding step, various known methods and known apparatus can be adopted.

As described above, in the positive electrode 10, the end surface 14a on the lower end side of the core metal 14 has a long shape. Then, one side and the other side of the elongated shape in the longitudinal direction of the lower end portion of the core metal 14 are recessed into the inner surface of the tubular hole 52h of the main body portion 52. Therefore, one end of the core metal 14 can be firmly fitted into the tubular hole 52h of the main body 52. It is possible to improve the fitability between the lower connecting seat 51 and the core metal 14.

In the positive electrode 10, the tubular hole 52h of the main body 52 includes a circular hole. The long shape of the core metal 14 is an elliptical shape having a major diameter larger than the diameter of the tubular hole 52h. According to this configuration, the lower end portion of the core metal 14 is effectively fitted into the inner surface of the tubular hole 52h, and the fitability between the lower joint seat 51 and the core metal 14 can be effectively improved.

The positive electrode 10 has a circular cross section at least at the upper end of the core metal 14. In this case, even if the core metal 14 is corroded and the core metal 14 is thinned, it is difficult to form a locally thinned portion at least at the upper end portion of the core metal 14. Therefore, it is possible to suppress the breakage of the core metal 14. Further, in this case, the active material is likely to be used evenly in the vicinity of at least the upper end portion of the core metal 14 inside the tubular body 12a. Therefore, it is possible to improve the current collecting property.

The positive electrode 10 has a cylindrical body 12a, and the positive electrode 10 has a cylindrical shape. In this case, the active material is likely to be used evenly inside the tubular body 12a. Therefore, it is possible to improve the current collecting property.

The positive electrode 10 is provided with an overhanging portion 59 formed by projecting from the inner surface on one side and the other side in the X direction on the inner surface of the tubular hole 52h when viewed from the Z direction. If the end surface 14a has a long shape with the Y direction as the longitudinal direction, a gap is formed between the end surface 14a and the inner surface of the tubular hole 52h in the X direction in the lateral direction. Therefore, it is possible to suppress the formation of the gap.

The lead storage battery 100 includes a positive electrode 10. Since the lead-acid battery 100 also includes the positive electrode 10, the above-mentioned effect that the fitability between the lower connecting seat 51 and the core metal 14 can be improved can be obtained.

The core metal 14 is a rod-shaped current collector inserted into the tubular body 12a in the positive electrode 10 provided with the tubular body 12a, the positive electrode material 16, and the lower connecting seat 51, and is the lower end portion on the lower connecting seat 51 side. The side end face 14a exhibits an elongated shape. The core metal 14 is used, for example, when the lower end portion is fitted into the lower joint seat 51, one side and the other side of the lower end portion in the longitudinal direction of the long shape are fitted into the lower joint seat 51. The lower end can be firmly fitted to the lower joint 51. It is possible to improve the fitability between the lower connecting seat 51 and the core metal 14.

The long shape of the end face 14a of the core metal 14 is an elliptical shape. In this case, for example, when the lower end portion of the core metal 14 is fitted into the lower joint seat 51, the lower end portion can be effectively fitted into the lower joint seat 51, and the lower joint seat 51 and the core metal 14 can be fitted together. It is possible to improve the fitability.

In the core metal 14, at least the upper end portion of the core metal 14 has a circular cross section. In this case, even if the core metal 14 is corroded, it is difficult to form a locally thinned portion at at least the upper end portion of the core metal 14. Therefore, it is possible to suppress the breakage of the core metal 14. Further, in this case, the active material is likely to be used evenly in the vicinity of at least the upper end portion of the core metal 14 inside the tubular body 12a. Therefore, it is possible to improve the current collecting property.

The method for manufacturing the core metal 14 is a method for manufacturing the core metal 14, in which the cutting step of cutting the rod-shaped member constituting the core metal 14 and the end face on the lower end side of the cut rod-shaped member are formed into a long shape. It is provided with a molding step of molding so as to be presented. According to the core metal 14 manufactured by this manufacturing method, the lower end portion of the core metal 14 can be firmly fitted to the lower connecting seat 51, and the fitability between the lower connecting seat 51 and the core metal 14 can be improved. It will be possible.

In the method of manufacturing the core metal 14, in the molding step, when the rod-shaped member is cut by the cutting step, the end face on the lower end side of the rod-shaped member is molded by utilizing the force required for the cutting. In this case, the long shape of the end surface 14a on the lower end side of the core metal 14 can be easily and efficiently realized.

Although the embodiments have been described above, one aspect of the present invention is not limited to the above embodiments.

In one aspect of the present invention, the end face 14a of the core metal 14 has an elliptical shape, but is not limited to the elliptical shape, and may be a long shape having a longitudinal direction. For example, as shown in FIG. 11A, the end face 14a of the core metal 14 may have a flat circular shape. Further, for example, as shown in FIG. 11B, the end face 14a of the core metal 14 may have an oval shape (track shape).

Further, for example, as shown in FIG. 11C, the end face 14a of the core metal 14 may have a rounded rectangular shape with rounded corners. Further, for example, as shown in FIG. 11D, the end face 14a of the core metal 14 may have a perfect circular shape on one side in the X direction and an elliptical or flat circular shape on the other side in the X direction. Further, for example, as shown in FIG. 11 (e), the end surface 14a of the core metal 14 has a shape in which the other side in the X direction is cut off (a shape in which the edge on the other side in the X direction extends linearly in the Y direction). ) May be. Incidentally, the end face 14a of the core metal 14 may have a shape in which at least one of the above-mentioned shapes is combined.

In the positive electrode 10 according to one aspect of the present invention, the cross section of the upper end portion and the central portion of the core metal 14 has a circular shape, but the cross section of only the upper end portion of the core metal 14 may have a circular shape.
In the positive electrode 10 according to one aspect of the present invention, the overhanging portions 59 are provided on one side and the other side in the X direction on the inner surface of the tubular hole 52h when viewed from the Z direction, but only on one side or the other side in the X direction. The overhanging portion 59 may be provided, and in some cases, the overhanging portion 59 may not be provided.

The shape and cross-sectional shape of the end face 14a of the core metal 14 according to one aspect of the present invention can be measured by various known methods. The shape and cross-sectional shape of the end face 14a of the core metal 14 can be measured, for example, by inspecting the positive electrode 10 after removing other parts by nondestructive inspection, X-ray inspection, dissolution inspection, grinding or polishing, or the like. May be good. The shape and cross-sectional shape of the end face 14a of the core metal 14 may be measured, for example, at a timing before fitting into the tubular hole 52h of the main body 52.

The positive electrode 10 and the lead-acid battery 100 provided with the lower joint 51 according to one aspect of the present invention can be used, for example, in an electric vehicle. Examples of electric vehicles include forklifts and golf carts. In the present invention, each configuration of the above-described embodiment and the above-mentioned modification may be appropriately combined. The present invention can be modified in various ways without departing from the gist thereof.

10 ... Positive electrode (electrode), 12a ... Cylindrical body, 14 ... Core metal (current collector), 14a ... End face, 16 ... Positive electrode material (electrode material), 51 ... Lower joint (sealing member), 52 ... Main body , 52h ... Cylinder hole, 59 ... Overhanging part, 100 ... Lead storage battery.

Claims

Sealing that seals a tubular body, a current collector that is inserted into the tubular body and has a rod shape, an electrode material that is filled inside the tubular body and contains an active material, and one end of the tubular body. An electrode with a member and
The sealing member has a tubular main body in which one end of the current collector is fitted.
The end face of the current collector on the one end side has a long shape having a longitudinal direction.
An electrode in which one end of the current collector and one side and the other side of the long shape in the longitudinal direction are recessed into the inner surface of a tubular hole of the main body.
The tubular hole of the main body includes a circular hole and includes a circular hole.
The electrode according to claim 1, wherein the long shape of the current collector is an elliptical shape, a flat circular shape, or an elliptical shape having a major axis larger than the diameter of the tubular hole as the circular hole.
The electrode according to claim 1 or 2, wherein the cross section of at least the other end of the current collector has a circular shape.
The electrode according to claim 3, wherein the tubular body has a cylindrical shape.
When viewed from the axial direction of the tubular hole, the inner surface of the current collector fitted in the tubular hole on the inner surface of the tubular hole is on one side, the other side, or both sides of the long shape in the lateral direction. The electrode according to any one of claims 1 to 4, wherein an overhanging portion is provided so as to project from the electrode.
A lead-acid battery comprising the electrode according to any one of claims 1 to 5.
An electrode provided with a tubular body, an electrode material filled inside the tubular body and containing an active material, and a sealing member for sealing one end of the tubular body, and inserted into the tubular body. It is a rod-shaped current collector that is used.
The end face on the one end side is a current collector having a long shape having a longitudinal direction.
The current collector according to claim 7, wherein the long shape is an oval shape, a flat circular shape, or an elliptical shape.
The current collector according to claim 7 or 8, wherein at least the other end has a circular cross section.
The method for manufacturing a current collector according to any one of claims 7 to 9.
A cutting step of cutting the rod-shaped member constituting the current collector, and
A method for manufacturing a current collector, comprising a molding step of molding an end surface of the cut rod-shaped member on one end side so as to exhibit the long shape.
The collection according to claim 10, wherein in the molding step, when the rod-shaped member is cut by the cutting step, the end face on the one end side of the rod-shaped member is molded by utilizing the force required for the cutting. Manufacturing method of electric body.