JP2012169161A - Cylindrical nonaqueous electrolyte battery and method for manufacturing the same - Google Patents

Abstract

A method for manufacturing a cylindrical non-aqueous electrolyte battery capable of preventing winding slippage and electrode plate breakage when winding an electrode group is provided.
A first electrode plate to which a first electrode lead is connected, a separator, and a second electrode plate to which a second electrode lead is connected are wound. The first electrode lead 210 has a plate-like portion and a round bar portion. The plate-like portion is formed with an anti-slip structure for reducing the slidability between the plate-like portion and the separator 27. With respect to the width direction of the first electrode plate 21 and the second electrode plate 22, the peripheral portion of the separator 27 protrudes from the first electrode plate 21 and the second electrode plate 22, and the round bar portion is positioned outside the peripheral portion of the separator 27. Let The first electrode plate 21, the separator 27, and the second electrode plate 22 are wound while overlapping the peripheral edge portion of the separator 27 and the anti-slip structure.
[Selection] Figure 6

Description

  The present invention relates to a cylindrical nonaqueous electrolyte battery and a method for manufacturing the same.

  Secondary batteries are used in various portable devices such as notebook computers. From the viewpoint of improving portability, extending driving time and stabilizing driving, secondary batteries for portable devices are required to be lighter, improve energy density, and improve reliability.

  As a secondary battery for portable equipment, a lithium ion secondary battery can be given. As a container for housing the electrode group, a container made of aluminum foil and a rectangular container made of metal are widely used.

  On the other hand, metal cylindrical containers are widely used in secondary batteries for the energy field. A secondary battery using a metal cylindrical container is generally manufactured by housing an electrode group in a container and sealing the opening of the container with a sealing plate. The two lead terminals connected to the electrode group are welded to the container and the sealing plate, respectively. The structure of the sealing plate is relatively complex and expensive. Also, the lead welding process is troublesome. Therefore, a battery having a structure of Patent Document 1 has been proposed.

  Patent Document 1 discloses a cylindrical non-aqueous electrolyte battery 880 as shown in FIG. The cylindrical nonaqueous electrolyte battery 880 includes an electrode group 820, a positive electrode lead 810, a negative electrode lead 910, a battery case 860, and a sealing body 870. The electrode group 820 is accommodated in the battery case 860. The positive electrode lead 810 and the negative electrode lead 910 have round bar portions 812 and 912, respectively. The sealing body 870 is made of rubber, and seals the opening of the battery case 860 while supporting the round bar portions 812 and 912.

JP-A-10-308206

  When the inventors of the present invention produced the cylindrical nonaqueous electrolyte battery described in Patent Document 1, the following problems occurred. Specifically, winding deviation occurred when the electrode group was wound, or the positive electrode plate and the negative electrode plate were cut. Such a problem is considered to be due to mutual interference between the electrode group and the lead.

  The present invention has been made in view of the above-described conventional problems, and a method for manufacturing a cylindrical non-aqueous electrolyte battery capable of preventing winding deviation and electrode plate breakage, and a cylindrical non-aqueous electrolyte manufactured by the manufacturing method. An object is to provide a battery.

In order to solve the above problems, the present invention provides:
A first electrode plate including a first active material capable of inserting and extracting lithium ions; and a second active material capable of inserting and extracting lithium ions and having a polarity opposite to that of the first electrode plate. Preparing an electrode plate and a separator wider than the first electrode plate and the second electrode plate;
Electrically connecting the first electrode lead and the second electrode lead to the first electrode plate and the second electrode plate, respectively;
With respect to the width direction of the first electrode plate and the second electrode plate, the peripheral edge of the separator protrudes from the first electrode plate and the second electrode plate, and the protruding direction of the first electrode lead from the first electrode plate Determining the relative positional relationship between the first electrode plate, the separator and the second electrode plate so that the second electrode lead protrudes from the second electrode plate.
Winding the first electrode plate, the separator and the second electrode plate so as to form a wound electrode group;
The step of putting the electrode group in the battery case and closing the opening of the battery case with the sealing body so that the first electrode lead and the second electrode lead extend outside the cylindrical battery case through the sealing body. And including
The first electrode lead includes a plate-like portion fixed to the first electrode plate, and a round bar portion formed integrally with the plate-like portion, and the first electrode lead in the thickness direction of the plate-like portion. The dimension of one electrode lead changes discontinuously at the boundary between the plate-like portion and the round bar portion,
In the plate-like portion, an anti-slip structure for reducing the slidability between the plate-like portion and the separator is formed at a position adjacent to the boundary,
Cylindrical non-water that performs the winding step while positioning the round bar portion outside the peripheral edge portion of the separator with respect to the width direction and overlapping the peripheral edge portion of the separator on the anti-slip structure. A method for producing an electrolyte battery is provided.

In another aspect, the present invention provides:
A first electrode plate including a first active material capable of inserting and extracting lithium ions; and a second active material capable of inserting and extracting lithium ions and having a polarity opposite to that of the first electrode plate. A wound electrode group having an electrode plate and a separator wider than the first electrode plate and the second electrode plate;
A cylindrical battery case containing the electrode group;
A sealing body closing the opening of the battery case;
A first electrode lead electrically connected to the first electrode plate and extending to the outside of the cylindrical battery case through the sealing body;
A second electrode lead electrically connected to the second electrode plate and extending to the outside of the cylindrical battery case through the sealing body,
The first electrode lead includes a plate-like portion fixed to the first electrode plate, and a round bar portion formed integrally with the plate-like portion, and the first electrode lead in the thickness direction of the plate-like portion. The dimension of one electrode lead changes discontinuously at the boundary between the plate-like portion and the round bar portion,
In the plate-like portion, an anti-slip structure for reducing the slidability between the plate-like portion and the separator is formed at a position adjacent to the boundary,
The peripheral edge of the separator projects from the first electrode plate and the second electrode plate with respect to the width direction of the first electrode plate and the second electrode plate,
Provided is a cylindrical nonaqueous electrolyte battery in which the round bar portion is located outside the peripheral portion of the separator with respect to the width direction, and the peripheral portion of the separator overlaps the anti-slip structure.

  When the first electrode plate is a positive electrode plate, the first electrode lead corresponds to the positive electrode lead, the first active material corresponds to the positive electrode active material, the second electrode plate corresponds to the negative electrode plate, and the second electrode lead corresponds to the negative electrode It corresponds to the lead, and the second active material corresponds to the negative electrode active material. When the first electrode plate is a negative electrode plate, the first electrode lead corresponds to the negative electrode lead, the first active material corresponds to the negative electrode active material, the second electrode plate corresponds to the positive electrode plate, and the second electrode lead is the positive electrode It corresponds to a lead, and the second active material corresponds to a positive electrode active material.

  According to the present invention, the dimension of the first electrode lead changes discontinuously at the boundary between the plate-like portion and the round bar portion. The plate-like portion of the first electrode lead is formed with an anti-slip structure for reducing the slidability between the plate-like portion and the separator. The winding step is performed while the round bar is positioned outside the peripheral edge of the separator with respect to the width direction, and the peripheral edge of the separator is stacked on the anti-slip structure. If it does in this way, it can prevent that the peripheral part of a separator receives an excessive load from the 1st electrode lead, or slips on the surface of the 1st electrode lead. Therefore, it is possible to prevent an excessive stress from being applied to the electrode group. According to the present invention, winding slip and electrode plate breakage can be prevented. In addition, according to the present invention, it is possible to provide a cylindrical non-aqueous electrolyte battery having an electrode group in which winding deviation due to external vibration or the like hardly occurs.

Sectional drawing of the cylindrical nonaqueous electrolyte battery which concerns on embodiment of this invention 1 is an exploded perspective view of the electrode group of the battery shown in FIG. Flow diagram (perspective view) for explaining a method of manufacturing an electrode lead Flow diagram for explaining the electrode lead manufacturing method (cross section) Plan view of electrode lead with irregularities formed as a non-slip structure Plan view of electrode lead with knurl formed as anti-slip structure A perspective view for explaining the lead attachment process on the positive electrode side A perspective view for explaining the lead attachment process on the negative electrode side Enlarged perspective view around the positive lead for explaining the lead attachment process Enlarged perspective view around the negative electrode lead for explaining the lead attachment process A perspective view for explaining a lamination process Enlarged perspective view around the positive electrode lead for explaining the lamination process Enlarged perspective view around the negative electrode lead for explaining the lamination process Flow chart for explaining the winding process Flow chart for explaining the accommodation process Flow chart for explaining the sealing process Sectional view of a conventional cylindrical nonaqueous electrolyte battery

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, a cylindrical nonaqueous electrolyte battery 80 (hereinafter also simply referred to as “battery 80”) of the present embodiment includes a cylindrical battery case 60 and an electrode group 20 accommodated in the battery case 60. And a sealing body 70 fixed to the opening of the battery case 60. The battery 80 is typically a lithium ion secondary battery.

  As shown in FIG. 2, the electrode group 20 includes a positive electrode plate 21, a negative electrode plate 22, and two separators 27. The positive electrode plate 21 includes a positive electrode current collector 23 and a positive electrode active material layer 24. The negative electrode plate 22 includes a negative electrode current collector 25 and a negative electrode active material layer 26. The separators 27 are respectively disposed between the positive electrode plate 21 and the negative electrode plate 22. A positive electrode lead 210 for extracting power is electrically connected to the positive electrode plate 21. A negative electrode lead 710 for taking out electric power is electrically connected to the negative electrode plate 22. The electrode group 20 is wound in a spiral shape and has a cylindrical shape as a whole. With respect to the winding axis of the electrode group 20, the positive electrode lead 210 faces the negative electrode lead 710.

  As shown in FIG. 1, the sealing body 70 is formed with through holes 70a and 70b. The positive electrode lead 210 is inserted into the through hole 70a of the sealing body 70 so as to be held by the sealing body 70 in the through hole 70a. Similarly, the negative electrode lead 710 is inserted into the through hole 70b of the sealing body 70 so as to be held by the sealing body 70 in the through hole 70b. That is, the positive electrode lead 210 and the negative electrode lead 710 extend to the outside of the battery case 60 through the through holes 70a and 70b, respectively. In the present embodiment, the length of the positive electrode lead 210 matches the length of the negative electrode lead 710 in the height direction of the battery case 60.

  A caulking portion that protrudes in a direction toward the central axis of the electrode group 20 between the upper surface 70p of the sealing body 70 and the lower surface 70q of the sealing body 70 in the side portion of the battery case 60 in the height direction of the battery case 60. 60a is provided. The caulking portion 60a is formed along the circumferential direction of the battery case 60 so as to have an annular shape. According to this configuration, a uniform compressive load can be applied to the sealing body 70 in the circumferential direction. In the opening of the battery case 60, a caulking portion 60b bent in a U-shape is provided. The caulking portion 60 b is in contact with the upper surface of the sealing body 70, thereby applying a load in a direction to be pushed into the battery case 60 to the sealing body 70.

  Note that another member such as an insulating sheet may be provided in the space at the bottom of the battery case 60, that is, between the bottom of the battery case 60 and the electrode group 20. Similarly, another member such as an insulating sheet may be provided between the lower surface 70 q of the sealing body 70 and the electrode group 20.

  Next, a method for manufacturing the battery 80 shown in FIG. 1 will be described.

[Component preparation process]
First, each member constituting the battery 80 is prepared.

(Electrode lead)
In the present embodiment, as shown in FIG. 3A, the positive electrode lead 210 is manufactured by processing the workpiece 10. An existing electrode lead can be used as the workpiece 10. The workpiece 10 has a plate-like part 11, a round bar part 12, a tip part 13, and a raised part 14.

  The plate-like portion 11 has a strip shape. In FIG. 3A, the longitudinal direction of the plate-like portion 11 is parallel to the x direction. The round bar portion 12 has a cylindrical shape. The round bar portion 12 is formed integrally with the plate-like portion 11. The tip portion 13 has a linear shape. The tip portion 13 is welded to the round bar portion 12 on the opposite side of the plate-like portion 11.

  As shown in FIG. 3B, the raised portion 14 is a region in the vicinity of the boundary between the plate-like portion 11 and the round bar portion 12 in the dimension of the workpiece 10 in the thickness direction of the plate-like portion 11 (y-direction shown in FIG. 3B). It is provided so as to change continuously.

First, the raised portion 14 of the workpiece 10 is removed. The method for removing the raised portion 14 is not limited. For example, the raised portion 14 may be scraped off with a file. After removing the raised portion 14, the dimension of the workpiece 110 in the thickness direction of the plate-like portion 11 changes discontinuously at the boundary between the plate-like portion 11 and the round bar portion 12. That is, the thickness d ₁ of the plate-like part 11 and the diameter d ₂ of the round bar part 12 are respectively constant, and the diameter d ₂ of the round bar part 12 is larger than the thickness d ₁ of the plate-like part. The round bar portion 12 has a diameter 2 to 10 times the thickness of the plate-like portion 11, for example. The thickness d ₁ of the plate-like portion 11 is, for example, 0.2 to 0.5 mm. The diameter d ₂ of the round bar portion 12 is, for example, 0.4～5Mm. Each structure of the plate-like portion 11 and the round bar portion 12 of the workpiece 110 is reflected in the positive electrode lead 210.

  Next, the groove 11 a is formed in the plate-like portion 11. The groove 11a extends in the width direction of the plate-like portion 11 (z direction shown in FIG. 3A). The width direction is a direction orthogonal to the longitudinal direction and the thickness direction of the plate-like portion 11. The groove 11a constitutes a non-slip structure that acts to reduce the sliding property of the plate-like portion 11 in the longitudinal direction, that is, to increase the coefficient of friction. In the present embodiment, the groove 11 a is formed in the plate-like portion 11 at a position adjacent to the boundary between the plate-like portion 11 and the round bar portion 12. In the present embodiment, the grooves 11 a are formed on the front and back surfaces of the plate-like portion 11. In this way, the positive electrode lead 210 is manufactured.

  In the present embodiment, a plurality of grooves 11a are formed. However, the groove 11a may be one groove. Moreover, the specific dimension of the groove | channel 11a is not limited. For example, the depth of the groove 11a may be 0.05 to 0.1 mm. Moreover, it is preferable to form the groove | channel 11a in the whole width direction. That is, one end of the groove 11 a may be located on one side surface of the plate-like portion 11, and the other end of the groove 11 a may be located on the other side surface of the plate-like portion 11. In this way, the separator 27 can also be captured by the side surface of the plate-like portion 11.

  Moreover, you may implement the removal of the protruding part 14, and formation of the groove | channel 11a by a single process. For example, both removal of the bulging part 14 and formation of the groove | channel 11a can be implemented by making a file contact the bulging part 14 and moving a file in the width direction. In this way, the positive electrode lead 210 can be obtained from the workpiece 10 in a single process. Therefore, the processing cost can be suppressed.

  Further, as the workpiece 10, a commercially available electrode lead may be used. Moreover, in this embodiment, although the workpiece 10 is processed and the positive electrode lead 210 is produced, this invention is not limited to this. For example, the positive electrode lead 210 may be produced directly from the raw material. Specifically, first, a wire having the same diameter as that of the round bar portion 12 is prepared. Next, the wire is cut to an appropriate length. Next, the cut wire is pressed so that the plate-like portion 11 is formed. Next, the raised portion 14 formed by pressing is removed by a processing method such as grinding or polishing. Finally, the tip portion 13 may be welded to the round bar portion 12.

  In this embodiment, the groove 11a constitutes an anti-slip structure. The anti-slip structure by the groove 11a is excellent in that the sliding property in the longitudinal direction of the plate-like portion 11 is lowered. However, the anti-slip structure may be configured in other manners. For example, the anti-slip structure may be constituted by unevenness, knurling, protrusions, or notches. As shown in FIG. 3C, the anti-slip structure constituted by the unevenness 11 b is excellent in that the slidability in all directions perpendicular to the thickness direction of the plate-like portion 11 is reduced. The unevenness 11b can be formed by roughening the surface of the plate-like part 11, for example. In FIG. 3C, the unevenness 11b is an unevenness having a size that can be visually observed, but the unevenness 11b may be a rough surface that cannot be visually observed. Further, the anti-slip structure constituted by the knurled 11c as shown in FIG. 3D is excellent in the same point as the anti-slip structure constituted by the unevenness 11b. The knurl 11c can be formed, for example, by plastically deforming the part by strongly pressing a die against the part of the plate-like part 11 where the anti-slip structure is to be formed. Further, the anti-slip structure constituted by the protrusions is also excellent in that the slidability of the plate-like portion 11 is lowered. Further, the anti-slip structure due to the notch is excellent in that the slidability of the plate-like portion 11 is reduced while the breakage of the separator 27 is suppressed.

  In the present embodiment, the negative electrode lead 710 has the same structure as the positive electrode lead 210. Therefore, the negative electrode lead 710 can also be produced by the same method as the positive electrode lead 210. As shown in FIGS. 3A and 3B, in the lead manufacturing process, the raised portions 514 are removed from the workpiece 510. A negative electrode lead 710 is obtained by forming a groove 511a in the workpiece 610 from which the raised portion 514 has been removed. The negative electrode lead 510 has a plate-like part 511, a round bar part 512, and a tip part 513. A groove 511a as an anti-slip structure is formed on the front surface and / or the back surface of the plate-like portion 511.

  Examples of the material for the positive electrode lead 210 and the negative electrode lead 710 include aluminum, aluminum alloy, nickel, nickel alloy, copper, copper alloy, and stainless steel. The negative electrode lead 710 may be made of the same material as the positive electrode lead 210 or may be made of a different material. In the positive electrode lead 210, the plate-like portion 11 and the round bar portion 12 are basically made of the same material. The distal end portion 13 may be made of the same material as the plate-like portion 11 and the round bar portion 12, or may be made of a different material. The same applies to the negative electrode lead 710.

(Positive electrode plate)
First, a positive electrode mixture is prepared by kneading a positive electrode active material and an arbitrary material. Optional materials include solvents, conductive aids, binders and the like. Next, the positive electrode mixture is applied to the positive electrode current collector 23. The positive electrode active material layer 24 is formed on the positive electrode current collector 23 by drying the applied positive electrode mixture. Next, the positive electrode current collector 23 and the positive electrode active material layer 24 are rolled so that the positive electrode plate 21 having a predetermined thickness is formed. Thereafter, the positive electrode plate 21 is cut into a predetermined dimension. Thereby, the strip-shaped positive electrode plate 21 is obtained. The positive electrode mixture may be applied to both surfaces of the positive electrode current collector 23, or the positive electrode mixture may be applied to one surface of the positive electrode current collector 23.

  The positive electrode current collector 23 is a conductive sheet-like member, and is typically composed of a metal foil. Instead of the metal foil, a member having a large number of holes (metal mesh, punching metal, expanded metal) can also be used. Examples of the material of the positive electrode current collector 23 include metals such as aluminum and aluminum alloys.

As the positive electrode active material, a material capable of inserting and extracting lithium ions can be used. Examples of such positive electrode active materials include manganese dioxide (MnO ₂ ), lithium manganese composite oxide (for example, Li _x Mn ₂ O ₄ or Li _x MnO ₂ ), lithium nickel composite oxide (for example, Li _x NiO ₂ ), lithium cobalt composite oxide (e.g., Li _x CoO _2), lithium nickel cobalt composite oxide (e.g., _{LiNi 1-y Co y O 2} ), lithium manganese cobalt composite oxides (e.g., _{Li x Mn y Co 1-y} O 2), Examples thereof include oxides such as spinel type lithium manganese nickel composite oxide (Li _x Mn _{2 -y} Ni _y O ₄ ) and lithium phosphorous oxide (Li _x FePO ₄ ) having an olivine structure. Each of “x” and “y” in the above chemical formula can take a value in the range of 0 to 1. Preferred positive electrode active materials include lithium manganese composite oxide, lithium nickel composite oxide, lithium cobalt composite oxide, lithium nickel cobalt composite oxide, spinel type lithium manganese nickel composite oxide, lithium manganese cobalt composite oxide, lithium phosphorus An acid iron is mentioned. These have a charge / discharge potential of, for example, 3.0 V or more and 5.0 V or less with respect to the potential of metallic lithium.

  As the conductive aid, carbon materials such as acetylene black, carbon black, and graphite can be used. As the binder, resin materials such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), carboxymethylcellulose (CMC), fluororubber, and styrene butadiene rubber (SBR) can be used.

(Negative electrode plate)
First, a negative electrode mixture is prepared by kneading a negative electrode active material and an arbitrary material. Optional materials include solvents, conductive aids, binders and the like. Next, the negative electrode mixture is applied to the negative electrode current collector 25. By drying the applied negative electrode mixture, the negative electrode active material layer 26 is formed on the negative electrode current collector 25. Next, the negative electrode current collector 25 and the negative electrode active material layer 26 are pressed so that the negative electrode plate 22 having a predetermined thickness is formed. Thereafter, the negative electrode plate 22 is cut into a predetermined dimension. Thereby, the strip-shaped negative electrode plate 22 is obtained. The negative electrode mixture may be applied to both surfaces of the negative electrode current collector 25, or the negative electrode mixture may be applied to one surface of the negative electrode current collector 25.

  The negative electrode current collector 25 is also a conductive sheet-like member, and is typically made of a metal foil. Instead of the metal foil, a member having a large number of holes (metal mesh, punching metal, expanded metal) can also be used. Examples of the material of the negative electrode current collector 25 include metals such as nickel, nickel alloy, copper, copper alloy, aluminum, and aluminum alloy.

As the negative electrode active material, a material capable of inserting and extracting lithium ions can be used. Preferred negative electrode active materials include, for example, metallic lithium, lithium alloys, lithium titanium composite oxides (for example, Li ₄ Ti ₅ O ₁₂ ), carbon materials that can occlude and release lithium ions, and materials that can form alloys with lithium ( So-called alloy-based active materials). An example of the carbon material is graphite. Examples of the alloy-based active material include tin, tin alloy, silicon, and silicon alloy. From the viewpoint of charge / discharge efficiency and cycle life, a carbon material or a lithium titanium composite oxide can be preferably used.

  Note that when the potential of the negative electrode active material included in the negative electrode plate 22 is 1.0 V or more higher than the potential of metallic lithium, it is preferable to use aluminum or an aluminum alloy as the material of the negative electrode current collector 25. Thereby, suitable aluminum or aluminum alloy can be used as the material of the battery case 60 for reasons described later. That is, when the negative electrode plate comes into contact with the battery case 60 made of aluminum or an aluminum alloy, the battery case 60 may be eluted. According to such a negative electrode plate 22, the elution of the battery case 60 can be prevented. it can.

As a negative electrode active material having a potential higher by 1.0 V or more than the potential of metallic lithium, a composite oxide containing lithium and titanium can be given. Specifically, lithium titanate represented by the chemical formula Li _{4 + x} Ti ₅ O ₁₂ (0 ≦ x ≦ 3) and having a spinel structure can be given. When lithium titanate is used for the negative electrode plate 22, the flexibility of the negative electrode plate 22 may be impaired. Electrode plates with poor flexibility tend to break during winding. Therefore, when using lithium titanate as a negative electrode active material, the method of this embodiment is particularly recommended.

  As the binder and the conductive additive for the negative electrode plate 22, the same materials as those for the positive electrode plate 21 can be used.

(Separator)
In this embodiment, two strip-shaped separators 27 that are wider than the positive electrode plate 21 and the negative electrode plate 22 are prepared. That is, the short side of the separator 27 is longer than the short side of the positive electrode plate 21 and the short side of the negative electrode plate 22. In the present embodiment, the long side of the separator 27 is longer than the long side of the positive electrode plate 21 and the long side of the negative electrode plate 22.

  Examples of the separator 27 include a porous film and a nonwoven fabric. Examples of the porous film include those made of polyethylene or polypropylene. Nonwoven fabrics include those made of cellulose or polyvinyl alcohol (PVA).

(Nonaqueous electrolyte)
In the present embodiment, a liquid nonaqueous electrolyte containing an electrolyte and an organic solvent is prepared. Examples of the organic solvent include cyclic carbonates such as ethylene carbonate (EC), propylene carbonate (PC), and vinylene carbonate (VC). Also, chain carbonates such as dimethyl carbonate (DMC), methyl ethyl carbonate (MEC), and diethyl carbonate (DEC), cyclic ethers such as tetrahydrofuran (THF) and 2 methyltetrahydrofuran (2MeTHF), chains such as dimethoxyethane (DME) An ether, acetonitrile (AN), sulfolane (SL) and the like may be used. These organic solvents can be used alone or in the form of a mixture of two or more.

Examples of the electrolyte include lithium salts such as lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate (LiPF ₆ ), and lithium tetrafluoroborate (LiBF ₄ ). From the viewpoint of chemical stability and high dielectric constant, it is preferable to use lithium hexafluorophosphate (LiPF ₆ ) as the main electrolyte. The “main electrolyte” means an electrolyte that is contained most in a molar ratio. The electrolyte is dissolved in the organic solvent at a concentration of 0.5 to 2.0 mol / L, for example.

(Battery case)
In the present embodiment, a cylindrical battery case 60 having a bottom and an opening is prepared. The material of the battery case 60 is preferably a metal material that is lightweight and excellent in workability. Moreover, in order to caulk the sealing body 70 as will be described later, it is preferable to select from among metal materials that can easily increase the caulking strength. Examples of the metal material that is lightweight and excellent in workability include aluminum and aluminum alloys. Examples of the metal material that can easily increase the caulking strength include an aluminum alloy to which a small amount of elements such as Cu, Mn, and Si are added. Of course, other metal materials such as stainless steel can also be used.

(Sealing body)
In the present embodiment, a cylindrical sealing body 70 made of an elastic material (elastomer) is prepared. The sealing body 70 is provided with through holes 70a and 70b. Examples of the material of the sealing body 70 include ethylene propylene diene rubber (EPDM), isobutylene isoprene rubber (IIR), and butadiene styrene rubber (SBR). The inner diameters of the through holes 70a and 70b are, for example, 0.2 to 4.9 mm.

  After preparing the above members, the battery 80 is assembled by the following steps.

[Lead mounting process]
First, as shown in FIG. 4A, the positive electrode lead 210 is electrically connected to the positive electrode plate 21. Specifically, the plate-like portion 11 of the positive electrode lead 210 is fixed to the positive electrode current collector 23 by welding. Examples of the welding method include resistance welding and ultrasonic welding. As shown in FIG. 4B, the negative electrode lead 710 is electrically connected to the negative electrode plate 22 in the same manner as the positive electrode plate 21.

  In the present embodiment, the positive electrode lead 210 and the positive electrode plate 21 are connected so that the groove 11a of the positive electrode lead 210 does not overlap the positive electrode plate 21 (see FIG. 4C). That is, the positive electrode lead 210 is connected to the positive electrode plate 21 so that a part of the plate-like portion 11 protrudes from the positive electrode plate 21 in the width direction of the positive electrode plate 21. In the plate-like portion 11, a groove 11 a (anti-slip structure) is formed only in a portion protruding from the positive electrode plate 21. Similarly, the negative electrode lead 710 and the negative electrode plate 22 are connected so that the groove 511a of the negative electrode lead 710 does not overlap the negative electrode plate 22 (see FIG. 4D). The same positional relationship as that of the positive electrode plate 21 and the positive electrode lead 210 is also adopted for the negative electrode plate 22 and the negative electrode lead 710.

  Further, in the present embodiment, when one end in the longitudinal direction (z direction shown in FIG. 4C) of the positive electrode plate 21 is defined as a position of 0% and the other end is defined as a position of 100%, the positive electrode lead 210 is the length of the positive electrode plate 21. The positive electrode lead 210 is connected to the positive electrode plate 21 so as to be within a range of 10 to 30% with respect to the direction. Similarly, when one end in the longitudinal direction (z direction shown in FIG. 4D) of the negative electrode plate 22 is defined as a 0% position and the other end is defined as a 100% position, the negative electrode lead 710 is 10 to 10 in the longitudinal direction of the negative electrode plate 22. The negative electrode lead 710 is connected to the negative electrode plate 22 so as to be positioned in the range of 30%. Thereby, the positive electrode lead 210 and the negative electrode lead 710 are arrange | positioned in an appropriate position after the below-mentioned winding process.

[Lamination process]
Next, as shown in FIG. 5A, the relative positional relationship between the positive electrode plate 21, the pair of separators 27, and the negative electrode plate 22 is determined. Specifically, the separator 27, the negative electrode plate 22, the separator 27, and the positive electrode plate 21 are arranged in this order. In this way, the laminate 30 having the electrode group 20, the positive electrode lead 210, and the negative electrode lead 710 is formed.

  In the lamination step, the relative positions of the members are adjusted so as to satisfy the following relationship. That is, as shown in FIGS. 5B and 5C, the peripheral portion 27a of the separator 27 is connected to the positive electrode plate 21 and the negative electrode plate 22 in the width direction of the positive electrode plate 21 and the negative electrode plate 22 (the x direction shown in FIGS. 5B and 5C). Protruding from. The protruding direction of the positive electrode lead 210 from the positive electrode plate 21 (the x direction shown in FIGS. 5B and 5C) coincides with the protruding direction of the negative electrode lead 710 from the negative electrode plate 22. With respect to the width direction of the positive electrode plate 21 and the negative electrode plate 22, all of the round bar portions 12 and all of the round bar portions 512 are located outside the peripheral edge portion 27a. The groove 11 a of the positive electrode lead 210 overlaps the peripheral edge portion 27 a of the separator 27. The groove 511 a of the negative electrode lead 710 also overlaps with the peripheral edge portion 27 a of the separator 27. Strictly speaking, the groove 11a overlaps only the peripheral edge 27a. Similarly, the groove 511a overlaps only the peripheral edge portion 27a.

  In the present embodiment, the groove 11 a is formed at a position adjacent to the boundary between the plate-like portion 11 and the round bar portion 12. Specifically, the position adjacent to the boundary between the plate-like portion 11 and the round bar portion 12 is a region from the boundary between the plate-like portion 11 and the round bar portion 12 to the outer edge of the positive electrode plate 21 closest to the boundary. It means the position included or the position included in the region from the boundary between the plate-like part 11 and the round bar part 12 to the outer edge of the negative electrode plate 22 closest to the boundary. More specifically, the position adjacent to the boundary between the plate-like part 11 and the round bar part 12 is a region from the boundary between the plate-like part 11 and the round bar part 12 to the outer edge of the positive electrode plate 21 closest to the boundary. And a position included in a region from the boundary between the plate-like portion 11 and the round bar portion 12 to the outer edge of the negative electrode plate 22 closest to the boundary.

[Winding process]
Next, as shown in FIG. 6, the laminated body 30 is wound. Specifically, first, the core 40 is connected to the end of the laminated body 30 so that the axial direction of the core 40 is along the short direction of the laminated body 30. Next, the laminated body 30 is wound around the core 40 while the peripheral edge 27a of the separator 27 is overlapped with the grooves 11a and 511a. Thereby, the wound electrode group 20 is obtained.

  As a comparative form, a case is assumed where an electrode lead having a raised portion such as the workpiece 10 in FIG. 3A is used as the positive electrode lead and the negative electrode lead, and a laminate is produced so that the raised portion is in contact with the separator. When such a laminate is wound, the separator wound on the outer peripheral side of the raised portion is likely to be displaced in a direction parallel to the winding axis. Therefore, winding deviation occurs, the positive electrode plate and the negative electrode plate are twisted, and the portion where the strength of the positive electrode plate and the negative electrode plate is weak is cut.

  On the other hand, according to this embodiment, the dimension of the positive electrode lead 210 in the thickness direction of the plate-like portion 11 changes discontinuously at the boundary between the plate-like portion 11 and the round bar portion 12. Furthermore, in the present embodiment, the round bar portion 12 is located outside the peripheral edge portion 27 a of the separator 27 in the width direction of the positive electrode plate 21. Therefore, the round bar portion 12 does not contact the separator 27 when the laminate 30 is wound. That is, in this embodiment, the factor that the separator 27 is shifted in the direction parallel to the winding axis is eliminated. The positive electrode plate 21, the negative electrode plate 22, and the separator 27 are kept parallel to the winding axis. Thereby, when winding the laminated body 30, winding deviation and cutting | disconnection of the positive electrode plate 21 and the negative electrode plate 22 can be prevented.

  Furthermore, in this embodiment, the groove 11 a of the positive electrode lead 210 overlaps the peripheral edge portion 27 a of the separator 27. The groove 11 a extends in a direction parallel to the outer edge of the separator 27. Thereby, the slidability between the separator 27 and the positive electrode lead 210 can be reduced. In particular, the separator 27 can be made difficult to slip in the direction parallel to the winding axis. Therefore, it is possible to more effectively prevent winding deviation and breakage of the positive electrode plate 21 and the negative electrode plate 22 when the laminate 30 is wound.

  Further, the groove 11 a overlaps only the peripheral edge portion 27 a of the separator 27. Therefore, the separator 27 is not sandwiched between the groove 11 a of the positive electrode lead 210 and the positive electrode plate 21. Thereby, when winding the laminated body 30, it can prevent that an excessive pressure is applied to the separator 27 from the groove | channel 11a. Therefore, when the laminated body 30 is wound, the separator 27 is hardly broken. Thereby, the electrical short circuit which arises when the separator 27 is torn can be prevented.

  In the present embodiment, since the grooves 11a are formed on the front surface and the back surface of the plate-like portion 11, the separator 27 can be more reliably prevented from slipping. However, even if the groove 11 a is formed only on one surface of the plate-like portion 11, an effect of preventing winding deviation and cutting of the positive electrode plate 21 and the negative electrode plate 22 can be obtained.

  In the present embodiment, the negative electrode lead 710 has the same structure as the positive electrode lead 210, and the positional relationship between the negative electrode lead 710 and the separator 27 is set in the same manner as the positional relationship between the positive electrode lead 210 and the separator 27. . Therefore, the above-described effect can be obtained for the negative electrode lead 710 as well.

  In the present embodiment, both the positive electrode lead 210 and the negative electrode lead 710 have a configuration for preventing the separator 27 from slipping. However, even if only one of the positive electrode lead 210 and the negative electrode lead 710 is configured as described above, it is possible to prevent winding deviation and disconnection of the positive electrode plate 21 and the negative electrode plate 22.

  In a general cylindrical secondary battery, the thickness of the lead is about 100 μm, so that winding deviation and electrode plate breakage due to the lead are unlikely to occur.

  On the other hand, in the battery 880 described with reference to FIG. 9, the positive electrode lead is fixed to the middle portion of the positive electrode plate. Similarly, a negative electrode lead is fixed to an intermediate portion of the negative electrode plate. That is, when the electrode group is wound, the positive electrode lead and the negative electrode lead are wound around the electrode group. For this reason, winding deviation and breakage of the positive electrode plate and the negative electrode plate are inherently likely to occur. In the present embodiment, since the configuration as described above is adopted, even if the positive electrode lead 210 and the negative electrode lead 710 are wound around the electrode group 20, winding deviation and disconnection of the positive electrode plate 21 and the negative electrode plate 22 can be prevented. .

[Containment process]
Next, as shown in FIG. 7, the electrode group 20 is accommodated in the battery case 60. When the electrode group 20 is accommodated in the battery case 60, a non-aqueous electrolyte (not shown) is injected into the battery case 60.

[Sealing process]
Next, as shown in FIG. 8, the opening of the battery case 60 is sealed with a sealing body 70. Specifically, the positive electrode lead 210 and the negative electrode lead 710 are sealed so as to extend from the through holes 70 a and 70 b provided in the sealing body 70 to the outside of the battery case 60, respectively. In the present embodiment, the round bar portion 12 and the round bar portion 512 are supported by receiving a pressing force from the sealing body 70 in the through holes 70a and 70b.

  Next, the battery case 60 is crimped and the sealing body 70 is fixed. Specifically, the caulking portion 60 a and the caulking portion 60 b are formed in the battery case 60. The caulking portion 60a is formed by denting the side surface of the battery case 60 toward the center. Further, the caulking portion 60b is formed by bending the opening-side end portion of the battery case 60 into a U-shape toward the center direction.

  Although the specific dimension of the sealing body 70 is not limited, it is preferable that the diameter of the sealing body 70 is somewhat larger than the inner diameter of the battery case 60 so that the sealing body 70 seals the opening of the battery case 60. Further, the inner diameters of the through holes 70a and 70b of the sealing body 70 are somewhat larger than the diameters of the round bar portion 12 and the round bar portion 512 so that the sealing body 70 and the round bar portion 12 and the round bar portion 512 are in close contact with each other. Small is preferable.

  In the battery 80 manufactured in this way, winding deviation in the electrode group 20 due to external vibration or the like hardly occurs. Therefore, the reliability of the battery 80 is high. Further, the battery 80 can omit a raised portion that causes winding slip when it contacts the electrode group 20. Further, if the raised portion is omitted, the positional relationship between the positive electrode lead 210 and the separator 27 is set so that the boundary between the plate-like portion 11 and the round bar portion 12 of the positive electrode lead 210 coincides with the long side of the separator 27. You can also. The positional relationship between the negative electrode lead 710 and the separator 27 can be set similarly. Therefore, according to the present embodiment, the battery 80 can be downsized (that is, the energy density can be increased).

(Example)
First, a positive electrode lead, a negative electrode lead, a positive electrode plate, a negative electrode plate, and a separator were prepared.

  A positive electrode lead was produced by the method described with reference to FIG. 3A. First, a capacitor lead (L3W20328FWPS manufactured by New Central Co., Ltd.) was prepared as a workpiece. Next, the raised portion of the workpiece was scraped off with a file. Next, the front and back surfaces of the 2 mm end region on the round bar portion side of the plate-like portion of the workpiece were shaved with a file. Thus, a groove extending in the width direction (z direction shown in FIG. 3A) was formed. In this way, a positive electrode lead was produced. Similarly, a negative electrode lead was produced.

  The positive electrode plate was produced as follows. First, a positive electrode active material, a conductive additive, a binder, and a solvent were stirred and kneaded with a double-arm kneader to prepare a positive electrode mixture. As the positive electrode active material, lithium cobaltate was used. As the conductive assistant, 2 parts by weight of acetylene black was used with respect to 100 parts by weight of the positive electrode active material. As the binder, 2 parts by weight of polyvinylidene fluoride was used with respect to 100 parts by weight of the positive electrode active material. As a solvent, an appropriate amount of N-methyl-2-pyrrolidone was used to make the solid content concentration of the positive electrode mixture about 50%.

  Next, the positive electrode mixture was applied to the front and back surfaces of a positive electrode current collector made of an aluminum foil having a thickness of 15 μm. The applied positive electrode mixture was dried, and a positive electrode active material layer was formed on the positive electrode current collector. Thereafter, the positive electrode current collector and the positive electrode active material layer were rolled, and the obtained positive electrode plate was cut into predetermined dimensions. In this way, a positive electrode plate having a width of 42 mm, a length of 580 mm, and a thickness of the positive electrode active material layer on one side of 50 μm was produced. This width is a specified value for the width of the positive electrode plate of the cylindrical battery.

The negative electrode plate was produced as follows. First, a negative electrode active material, a conductive additive, a binder, and a solvent were stirred and kneaded with a double-arm kneader to prepare a negative electrode mixture. As the negative electrode active material, lithium titanium composite oxide (Li ₄ Ti ₅ O ₁₂ ) was used. As the conductive assistant, 4 parts by weight of vapor grown carbon fiber (VGCF) was used with respect to 100 parts by weight of the negative electrode active material. As the binder, 5 parts by weight of polyvinylidene fluoride was used with respect to 100 parts by weight of the negative electrode active material. As the solvent, an appropriate amount of N-methyl-2-pyrrolidone was used to make the solid content concentration of the negative electrode mixture about 50%.

  Next, the negative electrode mixture was applied to the front and back surfaces of a negative electrode current collector made of an aluminum foil having a thickness of 15 μm. The applied negative electrode mixture was dried to form a negative electrode active material layer on the negative electrode current collector. Thereafter, the negative electrode current collector and the negative electrode active material layer were rolled, and the obtained negative electrode plate was cut into predetermined dimensions. In this way, a negative electrode plate having a width of 40 mm, a length of 540 mm, and a thickness of the negative electrode mixture layer on one side of 100 μm was produced. This width is a specified value of the width of the negative electrode plate of the cylindrical battery.

  As the separator, a cellulose film having a thickness of 25 μm, a width of 44 mm, and a length of 600 mm (manufactured by Nippon Kogyo Paper Industries Co., Ltd.) was used.

  Next, the positive electrode lead was welded to the positive electrode current collector. Specifically, the positive electrode lead was welded at a position of 110 mm from one end to the other end in the longitudinal direction (z direction in FIG. 4A) of the positive electrode plate. The positional relationship between the positive electrode lead and the positive electrode plate was set so that the boundary between the round bar portion and the plate-like portion protruded 1 mm outside the long side of the positive electrode plate (that is, in the positive direction of x in FIG. 4C).

  Next, the negative electrode lead was welded to the negative electrode current collector. Specifically, the negative electrode lead was welded at a position of 95 mm from one end to the other end in the longitudinal direction (z direction in FIG. 4B) of the negative electrode plate. The positional relationship between the negative electrode lead and the negative electrode plate was set so that the boundary between the round bar portion and the plate-like portion protruded 2 mm outside the long side of the negative electrode plate (that is, in the positive direction of x in FIG. 4D).

  For welding, an ultrasonic welder (metal welder 2000ea type manufactured by Nippon Emerson Co., Ltd.) was used. The weld time was set to 0.1 second and the amplitude was set to 80%.

  Next, a separator, a negative electrode plate, a separator, and a positive electrode plate were arranged in this order to form a laminate having an electrode group, a positive electrode lead, and a negative electrode lead. With respect to the width direction of the separator (the x direction shown in FIG. 5A), the positional relationship between the two separators and the negative electrode plate was set so that the two separators protruded 2 mm out of the negative electrode plate. Similarly, the positional relationship between the two separators and the positive electrode plate was set so that the two separators protruded 1 mm out of the positive electrode plate with respect to the width direction of the separator. In other words, in this embodiment, the positive electrode plate is formed such that the boundary between the round bar portion and the plate-like portion in the positive electrode lead, the boundary between the round bar portion and the plate-like portion in the negative electrode lead, and the long sides of the two separators coincide. The positional relationship between the negative electrode plate and the two separators was set.

  Next, a winding core was attached to one end in the longitudinal direction of the laminate. Then, the laminate was wound using a winding machine while applying a tension of about 10 N to obtain a wound electrode group. Finally, the outermost periphery of the electrode group was fixed with an adhesive tape.

(Comparative example)
Capacitor leads (L3W20328FWPS manufactured by New Central Co.) having raised portions such as those of the electrode lead of FIG. 3A were used as the positive electrode lead and the negative electrode lead. Moreover, the laminated body was produced so that a protruding part and a separator might overlap. Otherwise, an electrode group was prepared in the same manner as in the example.

[Evaluation]
The electrode group of the example and the electrode group of the comparative example were compared visually. In the electrode group of the example, winding slip and breakage of the positive electrode plate and the negative electrode plate did not occur. On the other hand, in the electrode group of the comparative example, winding deviation and breakage of the positive electrode plate and the negative electrode plate occurred.

  The present invention can be applied to a secondary battery for the energy field, for example, a secondary battery for general household use.

10, 510, 110, 610 Workpiece 11,511 Plate-like part 11a, 511a Groove (non-slip structure)
11b Concavity and convexity (non-slip structure)
11c Knurled (non-slip structure)
DESCRIPTION OF SYMBOLS 12,512 Round bar part 13,513 Tip part 14,514 Raised part 20 Electrode group 21 Positive electrode plate 22 Negative electrode plate 23 Positive electrode current collector 24 Positive electrode active material layer 25 Negative electrode current collector 26 Negative electrode active material layer 27 Separator 27a Peripheral part 30 Laminated body 40 Winding core 60 Battery case 60a, 60b Caulking part 70 Sealing body 70a, 70b Through hole 70p Upper surface 70q Lower surface 80 Cylindrical nonaqueous electrolyte battery 210 Positive electrode lead 710 Negative electrode lead

Claims (6)

A first electrode plate including a first active material capable of inserting and extracting lithium ions; and a second active material capable of inserting and extracting lithium ions and having a polarity opposite to that of the first electrode plate. Preparing an electrode plate and a separator wider than the first electrode plate and the second electrode plate;
Electrically connecting the first electrode lead and the second electrode lead to the first electrode plate and the second electrode plate, respectively;
With respect to the width direction of the first electrode plate and the second electrode plate, the peripheral edge of the separator protrudes from the first electrode plate and the second electrode plate, and the protruding direction of the first electrode lead from the first electrode plate Determining the relative positional relationship between the first electrode plate, the separator and the second electrode plate so that the second electrode lead protrudes from the second electrode plate.
Winding the first electrode plate, the separator and the second electrode plate so as to form a wound electrode group;
The step of putting the electrode group in the battery case and closing the opening of the battery case with the sealing body so that the first electrode lead and the second electrode lead extend outside the cylindrical battery case through the sealing body. And including
The first electrode lead includes a plate-like portion fixed to the first electrode plate, and a round bar portion formed integrally with the plate-like portion, and the first electrode lead in the thickness direction of the plate-like portion. The dimension of one electrode lead changes discontinuously at the boundary between the plate-like portion and the round bar portion,
In the plate-like portion, an anti-slip structure for reducing the slidability between the plate-like portion and the separator is formed at a position adjacent to the boundary,
Cylindrical non-water that performs the winding step while positioning the round bar portion outside the peripheral edge portion of the separator with respect to the width direction and overlapping the peripheral edge portion of the separator on the anti-slip structure. Manufacturing method of electrolyte battery.   The method for manufacturing a cylindrical nonaqueous electrolyte battery according to claim 1, wherein the anti-slip structure is formed on a front surface and a back surface of the plate-like portion.   3. The cylindrical nonaqueous electrolyte battery according to claim 1, wherein the anti-slip structure includes a groove formed on a front surface and / or a back surface of the plate-like portion along a direction parallel to an outer edge of the separator. Manufacturing method.   3. The method for manufacturing a cylindrical nonaqueous electrolyte battery according to claim 1, wherein the anti-slip structure includes irregularities formed on a front surface and / or a back surface of the plate-like portion. The first electrode plate has one end and the other end in the longitudinal direction;
When the one end is defined as 0% position in the longitudinal direction and the other end is defined as 100% position in the longitudinal direction,
5. The first electrode lead according to claim 1, wherein the first electrode lead is connected to the first electrode plate such that the first electrode lead is located in a range of 10 to 30% with respect to the longitudinal direction. A method for producing a cylindrical non-aqueous electrolyte battery. A first electrode plate including a first active material capable of inserting and extracting lithium ions; and a second active material capable of inserting and extracting lithium ions and having a polarity opposite to that of the first electrode plate. A wound electrode group having an electrode plate and a separator wider than the first electrode plate and the second electrode plate;
A cylindrical battery case containing the electrode group;
A sealing body closing the opening of the battery case;
A first electrode lead electrically connected to the first electrode plate and extending to the outside of the cylindrical battery case through the sealing body;
A second electrode lead electrically connected to the second electrode plate and extending to the outside of the cylindrical battery case through the sealing body,
The first electrode lead includes a plate-like portion fixed to the first electrode plate, and a round bar portion formed integrally with the plate-like portion, and the first electrode lead in the thickness direction of the plate-like portion. The dimension of one electrode lead changes discontinuously at the boundary between the plate-like portion and the round bar portion,
In the plate-like portion, an anti-slip structure for reducing the slidability between the plate-like portion and the separator is formed at a position adjacent to the boundary,
The peripheral edge of the separator projects from the first electrode plate and the second electrode plate with respect to the width direction of the first electrode plate and the second electrode plate,
A cylindrical non-aqueous electrolyte battery in which the round bar portion is located outside the peripheral portion of the separator with respect to the width direction, and the peripheral portion of the separator overlaps the anti-slip structure.

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