JP2011154788A - Battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flat silver oxide battery having superior load characteristics. <P>SOLUTION: The battery has an electrode wound-around body with a sheet-shaped cathode and a sheet-shaped anode wound around with a separator interposed, and the sheet-shaped cathode is composed of a cathode mixture sheet containing a cathode active material, a conductive assistant, and a binder pressure-adhered on one surface or both surfaces of a metallic current collector. The current collector of the sheet-shaped cathode has projections on its surface and the projections intrude into the sheet-shaped cathode mixture. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a battery comprising an electrode winding body in which a positive electrode having a positive electrode mixture sheet and a current collector and a negative electrode are wound in a spiral through a separator, and the positive electrode mixture sheet in the positive electrode The present invention relates to a battery in which the adhesion between the electrode and the current collector is good and the winding of the electrode winding body hardly occurs.

  For example, in the case of a cylindrical battery, a battery having a structure in which an electrode winding body formed by winding a sheet-like positive electrode and a sheet-like negative electrode with a separator in a cylindrical outer can is known. .

  As a sheet-like positive electrode used in the battery as described above, a positive electrode mixture in which a positive electrode active material, a conductive additive, a binder, and the like are mixed is dispersed in a solvent to form a paint, and this is used as a current collector such as a metal foil. What was manufactured through the process of apply | coating to the surface and drying and forming a positive mix layer is used widely.

  Here, from the viewpoint of increasing the capacity of the battery, for example, it is conceivable to increase the filling amount of the positive electrode active material by increasing the thickness of the positive electrode mixture layer. However, the coating material containing the positive electrode mixture as described above is collected. In the manufacturing method including the step of applying to the surface of the electric body, it is difficult to increase the thickness of the positive electrode mixture layer. Therefore, for example, in a primary battery, the positive electrode mixture is uniformly stretched into a sheet by pressing or the like, and this positive electrode mixture sheet is pressed on the surface of the current collector by pressing it overlaid with a metal foil or the like as a current collector. A sheet-like positive electrode in which a positive electrode mixture layer is formed on the surface of a current collector by pressing a positive electrode mixture sheet may be used (for example, Patent Document 1). With such a manufacturing method, since the positive electrode mixture sheet constituting the positive electrode mixture layer can be easily thickened, a sheet-like positive electrode having a large positive electrode mixture layer can be obtained.

JP 2008-192383 A

  By the way, in a battery, it is preferable that the adhesiveness of a positive mix layer and a collector is high from a viewpoint of improving the load characteristic, for example.

  However, since the positive electrode mixture layer expands during battery discharge, the adhesion between the positive electrode mixture layer and the current collector may be impaired. In the case of the positive electrode formed by pressing the thick positive electrode mixture sheet and the current collector as described above, the amount of expansion of the positive electrode mixture layer (positive electrode mixture sheet) accompanying the discharge of the battery becomes very large. The adhesion between the positive electrode mixture layer and the current collector is particularly liable to be impaired.

  Further, in a battery having a positive electrode in which the amount of expansion of the positive electrode mixture layer accompanying the discharge of the battery is large, a positional shift between the positive electrode mixture layer and the current collector occurs, and thus the electrode winding body particularly after storage of the battery. There is also a risk of loosening.

  For example, when the positive electrode mixture sheet and the current collector are pressure-bonded, a higher press pressure is applied to improve the adhesion between the positive electrode mixture layer (positive electrode mixture sheet) and the current collector in advance. It is also conceivable to suppress as much as possible the decrease in adhesion due to the discharge of the battery, but since the positive electrode mixture sheet is usually soft, if the press pressure at the time of pressure bonding with the current collector is too high, There is a problem that cracks occur in the positive electrode mixture sheet.

  The present invention has been made in view of the above circumstances, and has an object of winding an electrode in which a positive electrode having a positive electrode mixture sheet and a current collector and a negative electrode are wound in a spiral shape via a separator. It is an object of the present invention to provide a battery having a body, which has good adhesion between a positive electrode mixture sheet and a current collector in a positive electrode, and hardly causes loosening of an electrode winding body.

  The battery of the present invention capable of achieving the object is a battery having an electrode winding body in which a sheet-like positive electrode and a sheet-like negative electrode are wound via a separator, and the sheet-like positive electrode is a positive electrode active material. A positive electrode mixture sheet containing a conductive additive and a binder is bonded to one or both sides of a metal current collector, and the current collector of the sheet-like positive electrode has protrusions on the surface thereof. The protrusions penetrate into the sheet-like positive electrode mixture.

  In the battery of the present invention, the current collector of the sheet-like positive electrode has a protrusion, and this protrusion penetrates into the positive electrode mixture sheet that is pressure-bonded to the current collector. Therefore, the adhesion between the positive electrode mixture sheet (positive electrode mixture layer) and the current collector in the positive electrode is good, and even if the positive electrode material sheet expands due to discharge, the positive electrode material mixture sheet and the current collector Is less likely to occur, and loosening of the electrode winding body (especially loosening of the electrode winding body after storage of the battery) is suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesiveness of the positive mix sheet and electrical power collector in a positive electrode is favorable, and the battery which does not produce loose winding of an electrode winding body easily can be provided.

It is a vertical side view showing typically an example of the battery of the present invention. It is a figure which shows typically the partial cross section of the longitudinal direction of an example of the sheet-like positive electrode concerning the battery of this invention. It is a top view which represents typically an example of the collector of the sheet-like positive electrode which concerns on the battery of this invention. It is a cross-sectional enlarged view of the width direction of the collector shown in FIG. It is a top view which represents typically the other example of the electrical power collector of the sheet-like positive electrode which concerns on the battery of this invention. FIG. 6 is an enlarged cross-sectional view of the current collector shown in FIG. 5 in the width direction. It is a principal part cross-sectional enlarged view of the longitudinal direction of the collector of the sheet-like positive electrode which concerns on the battery of this invention.

  FIG. 1 is a longitudinal side view showing an example of the battery of the present invention. In FIG. 1, a battery 1 is formed by winding a bottomed cylindrical outer can 2 having an upper opening, a sheet-like positive electrode 4 and a sheet-like negative electrode 5 loaded in the outer can 2 via a separator 6. It has the sealing structure which seals the electrode winding body 3 which becomes, electrolyte solution, and the upper opening part of the armored can 2. FIG. In other words, the battery 1 of FIG. 1 has the sheet-like positive electrode 4 and the sheet-like negative electrode 5 interposed between the outer can 2 and the sealing structure that seals the upper opening of the outer can 2 with the separator 6 interposed therebetween. And a power generation element such as an electrode winding body 3 and an electrolytic solution. The outer can 2 is made of iron, stainless steel, or the like.

  The sealing structure is attached to the cover plate 8 fixed to the inner peripheral edge of the upper opening of the outer can 2 and the opening formed in the center of the cover plate 8 through an insulating packing 9 made of polypropylene or the like. Terminal body 10 and insulating plate 11 disposed below cover plate 8. The insulating plate 11 is formed in a round plate shape that opens upward with an annular side wall 13 standing on the periphery of the disk-shaped base portion 12, and a gas passage 14 is opened at the center of the base portion 12. Yes. The cover plate 8 is fixed to the inner peripheral edge of the upper opening of the outer can 2 by laser welding or a crimp seal through packing while being received by the upper end of the side wall 13. As a countermeasure when the battery internal pressure suddenly increases, a thin portion (vent) can be provided on the lid 8 or the can bottom 2a of the outer can 2. The positive electrode 4 and the lower surface of the terminal body 10 are connected by a positive electrode lead body 15. Further, the negative electrode lead body 16 attached to the negative electrode 5 is welded to the upper inner surface of the outer can 2.

  In the battery of the present invention, a laminate film exterior body made of an aluminum laminate film or the like can be used as the exterior body (battery container) in addition to the above exterior can.

  The battery of the present invention includes a non-aqueous electrolyte battery having a non-aqueous electrolyte and an alkaline battery having an alkaline electrolyte (alkaline aqueous solution). Moreover, the battery of this invention can also be made into a form of a primary battery or a secondary battery by selection of a positive electrode or a negative electrode. Hereinafter, the configuration of the battery of the present invention will be described in detail.

<Positive electrode>
As the sheet-like positive electrode according to the battery of the present invention, for example, a positive electrode mixture (slurry) obtained by blending a positive electrode active material with a conductive additive or a binder and adding water or the like as necessary is used as a roll. The positive electrode mixture sheet formed into a sheet shape by rolling and rolling again to a pre-sheet such as by rolling the sheet, and then rolling and rolling it again is stacked on one or both sides of the current collector. An adhesive sheet and a current collector are pressure-bonded and a layer (positive electrode mixture layer) made of a positive electrode mixture sheet is formed on one side or both sides of the current collector.

  Specifically, for example, the current collector is overlapped by 3 mm so that the current collector is located several mm inside the two positive electrode mixture sheets, and 3 to 3 from the end in the length direction that becomes the winding start end. A sheet-like positive electrode can be produced by pressing a 10 mm portion. From the viewpoint of work, it is preferable that the two positive electrode mixture sheets and the positive electrode current collector are pressure-bonded prior to the production of the electrode winding body. The sheet may be pressure-bonded at the time of winding the electrode winding body, and there is no particular problem in terms of characteristics even by such a manufacturing method.

  As the positive electrode active material, for example, in the case of a non-aqueous electrolyte battery, an oxide such as manganese, cobalt, nickel, magnesium, copper, iron, niobium; a composite oxide thereof; a composite oxidation of these with lithium In the case where the product; fluorinated graphite; etc. is an alkaline battery, manganese dioxide, nickel oxyhydroxide, silver oxide and the like can be mentioned.

  Moreover, as a conductive support agent, graphite, carbon black (Ketjen black etc.), acetylene black etc. are mentioned, for example, These may be used individually by 1 type, and may use 2 or more types together. As the binder, fluorine resins such as polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF); rubber binders, and the like can be used. In the case of a fluororesin such as PTFE or PVDF, a dispersion type or a powder type may be used, but a dispersion type is particularly preferable.

  In the positive electrode mixture layer relating to the sheet-like positive electrode, for example, the content of the positive electrode active material is 92 to 97% by mass, the content of the conductive additive is 2 to 4% by mass, and the content of the binder is 1 to 4% by mass. % Is preferable. In addition, the thickness of the positive electrode mixture layer (when formed on both sides of the current collector, the thickness per side) is preferably, for example, 100 to 2000 μm.

It is preferable that the density of the positive mix layer concerning a sheet-like positive electrode is 2.1-2.8 g / cm < ³ >, for example. In addition, the density of a sheet-like positive electrode as used in this specification is a value calculated | required by the volume and mass of the positive electrode mixture layer of a dry state.

  As the current collector for the sheet-like positive electrode, one having projections on the surface is used. The protrusions of the current collector enter the positive electrode mixture sheet (positive electrode mixture layer), thereby improving the adhesion between the positive electrode mixture sheet and the current collector. Therefore, in the battery of the present invention, load characteristics can be enhanced, and loosening of the wound electrode body during storage can be suppressed.

  FIG. 2 shows an example of a sheet-like positive electrode according to the battery of the present invention. FIG. 2 is a partial cross-sectional view in the longitudinal direction of the sheet-like positive electrode 4. The sheet-like positive electrode 4 shown in FIG. 2 is configured by positive electrode mixture sheets (positive electrode mixture layers) 41 and 41 being bonded to both sides of a current collector 42 having a plurality of protrusions 42a on both sides. The protrusions 42 a of the body 42 enter the positive electrode mixture sheets 41 and 41.

  3 and 4 show an example of a sheet-like positive electrode current collector according to the battery of the present invention. 3 is a plan view schematically showing the current collector 42, and FIG. 4 is an enlarged cross-sectional view in the width direction (direction perpendicular to the longitudinal direction) of the current collector 42 shown in FIG. The current collector 42 shown in FIGS. 3 and 4 has a plurality of triangular protrusions 42a on its surface in plan view.

  Further, FIGS. 5 and 6 show other examples of the current collector of the sheet-like positive electrode according to the battery of the present invention. 5 is a plan view schematically showing the current collector 42, and FIG. 6 is an enlarged cross-sectional view in the width direction (direction perpendicular to the longitudinal direction) of the current collector 42 shown in FIG. The current collector 42 shown in FIGS. 5 and 6 has a plurality of trapezoidal protrusions 42a on the surface thereof in plan view. 3 to 6 is the same as the current collector 42 according to the sheet-like positive electrode 4 shown in FIG.

  The shape of the protrusions of the current collector is not particularly limited, and in a plan view, a triangle (equilateral triangle, isosceles triangle, etc.) as shown in FIG. 3, a quadrangle (square, rectangle, trapezoid, etc.) as shown in FIG. ) And other infinite polygons. Further, all of the protrusions may have the same shape, or may have different shapes for each protrusion. However, it is preferable that all the protrusions have the same shape from the viewpoint of facilitating the production of the current collector having the protrusions.

  The material of the protrusion is not particularly limited as long as it can exist stably without causing a chemical reaction in the battery, and may be a conductor or an insulator. However, from the viewpoint of further increasing the conductivity between the positive electrode mixture layer (positive electrode mixture sheet) and the current collector, the protrusions are preferably made of a conductor. From the viewpoint of facilitating the production of the current collector having protrusions, it is preferable that the entire current collector including the protrusions is made of a single material.

  The protrusions of the current collector are preferably inclined in the direction opposite to the winding direction of the electrode winding body. For example, in the sheet-like positive electrode 4 shown in FIG. 2, the left side in the drawing is the winding center side of the electrode winding body, the right side in the drawing is the outermost peripheral side of the electrode winding body, and the direction from left to right in the drawing is Winding direction. Therefore, as shown in FIG. 2, the protrusion 42a of the current collector 42 is preferably inclined in the direction opposite to the winding direction, that is, toward the left side in the drawing. Since the protrusions of the current collector are inclined in this way, the effect of preventing the loosening of the electrode winding body is particularly improved.

  In FIG. 7, the principal part enlarged view of the longitudinal direction cross section of the collector which concerns on a sheet-like positive electrode is shown. In FIG. 7, the background portion of the cross section is omitted for the purpose of facilitating understanding of each component. When the protrusions of the current collector are inclined in the direction opposite to the winding direction of the electrode winding body, the angle between the main body part of the current collector (excluding the protrusions; the same applies hereinafter) and the protrusion [ In FIG. 7, angle a. Hereinafter, it is referred to as an inclination angle a. ] Is from 15 to 60 ° from the viewpoint of more effectively ensuring the effects of the protrusions (adhesion improvement effect between the positive electrode mixture sheet and the current collector and the effect of preventing the loosening of the electrode winding body). preferable.

  In the sheet-like positive electrode, from the viewpoint of improving the adhesion between the positive electrode mixture sheet (positive electrode mixture layer) and the current collector, the intrusion position of the protrusion in the positive electrode mixture sheet is The position from the current collector side surface is preferably 1/5 or more of the thickness of the positive electrode mixture sheet. Therefore, it is desirable that the protrusions of the current collector have a size that can enter the position of the positive electrode mixture sheet while satisfying the inclination angle a. Further, the intrusion position of the protrusion in the positive electrode mixture sheet is preferably from the current collector side surface of the positive electrode mixture sheet to a position that is ½ of the thickness of the positive electrode mixture sheet. It is desirable to adjust the size.

From the viewpoint of improving the adhesion between the positive electrode material mixture sheet (positive electrode material mixture layer) and the current collector, the number of protrusions the current collector has is one side of the current collector in a plan view of the current collector. The number is preferably 5 or more per 1 cm ² of the area. However, if the number of protrusions of the current collector is increased too much, for example, when a protrusion is formed by cutting a part of a foil-like current collector as will be described later, the gap area of the current collector main body is small. Since the current collector is too large, the number of protrusions of the current collector is preferably 30 or less per 1 cm ² of the current collector in plan view on one side of the current collector.

  As a method for producing a current collector having a protrusion, for example, a method of manufacturing a metal plate used for the current collector by cutting the metal plate while leaving a part thereof; a metal piece or resin for forming the protrusion A method of manufacturing by attaching a piece or the like to a metal plate, metal net, punching metal or the like used for the current collector; a method of manufacturing by embossing the metal plate used for the current collector; Is mentioned. In addition, the manufacturing method of the electrical power collector which has protrusion is not necessarily limited to these manufacturing methods, You may manufacture by another method. However, it is easy to manufacture a current collector having protrusions, and since the protrusions become conductors, the metal plate is manufactured by forming protrusions by a method of cutting a part of the metal plate, A method of manufacturing by embossing a metal plate to form protrusions is more preferable.

  Examples of the constituent material of the main body portion of the current collector include stainless steel such as SUS316, SUS430, and SUS444. Moreover, since the constituent material of the protrusion is preferably the same material as the constituent material of the current collector body as described above, these stainless steels are recommended.

  The thickness of the main body portion of the current collector is preferably 0.1 to 0.4 mm, for example. Moreover, it is preferable that the thickness of a protrusion is also equivalent to the main-body part of an electrical power collector, and specifically, it is preferable that it is 0.1-0.4 mm.

  It is desirable to apply a conductive material (for example, a paste-like conductive material) to the surface of the current collector. When using a net-like material with a three-dimensional structure as a current collector, the current collection effect is significantly improved by applying a conductive material, as in the case of using an essentially flat material such as metal foil or punching metal. Is recognized. This is not limited to the route in which the metal part of the mesh current collector is in direct contact with the positive electrode mixture layer (positive electrode mixture sheet), but the route through the conductive material filled in the mesh is used effectively. It is presumed to be due to what has been done.

  As the conductive material, for example, silver paste or carbon paste can be used. In particular, the carbon paste is suitable for reducing the manufacturing cost of the battery because the material cost is lower than that of the silver paste and the contact effect is almost the same as that of the silver paste. As the binder for the conductive material, it is preferable to use a heat resistant material such as water glass or an imide binder. This is because the drying process is performed at a high temperature exceeding 200 ° C. when moisture in the positive electrode mixture layer is removed.

<Negative electrode>
The sheet-like negative electrode according to the battery of the present invention is composed of, for example, a metal lithium foil that is a negative electrode active material and a metal foil that is a negative electrode current collector in both non-aqueous electrolyte batteries and alkaline batteries. Things. Examples of the material for the metal lithium foil include not only metal lithium but also lithium alloys such as lithium-aluminum. The thickness of the metal lithium foil is preferably 0.15 to 0.4 mm, for example.

  Examples of the material for the current collector of the sheet-like negative electrode include copper, nickel, iron, and stainless steel. The current collector of the sheet-like negative electrode is preferably as small as possible because the internal volume of the outer can decreases by the thickness, and specifically, for example, 0.1 mm or less. Recommended. That is, if the current collector of the sheet-like negative electrode is too thick, the amount of metal lithium foil or the like that is the negative electrode active material must be reduced, and the battery capacity may be reduced. Moreover, since it will become easy to tear when the collector of a sheet-like negative electrode is too thin, it is desirable that the thickness shall be 0.005 mm or more. Further, the current collector of the sheet-like negative electrode preferably has a width equal to or wider than the width of the metal lithium foil, and the area is 100 to 130 of the area of the metal lithium foil arranged on one side. % Is preferred. By making the area of the current collector as described above, the width of the current collector is the same as or wider than the width of the metal lithium foil, and the length becomes longer. Therefore, the metal lithium foil is formed along the periphery of the current collector. It is possible to prevent the electrical connection from being cut off.

  Also, in the sheet-like negative electrode current collector, similar to the sheet-like positive electrode current collector, protrusions may be provided on the surface thereof. In the case where the protrusion is formed on the negative electrode current collector, the shape (including the inclined state), the number, and the size are preferably the same as those of the positive electrode current collector.

<Electrolyte>
As the electrolyte, when the battery of the present invention is a non-aqueous electrolyte battery, for example, cyclic carbonates such as propylene carbonate, ethylene carbonate, butylene carbonate, vinylene carbonate; dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, etc. 1,2-dimethoxyethane, diglyme (diethylene glycol methyl ether), triglyme (triethylene glycol dimethyl ether), tetraglyme (tetraethylene glycol dimethyl ether), 1,2-dimethoxyethane, 1,2- By dissolving the electrolyte in a concentration of about 0.3 to 2.0 mol / L in one kind of solvent selected from ethers such as diethoxymethane and tetrahydrofuran; Non-aqueous electrolyte prepared Te is used.

Examples of the electrolyte include LiBF ₄ , LiPF ₆ , LiAsF ₆ , LiSbF ₆ , LiClO ₄ , LiCF ₃ SO ₃ , LiC ₄ F ₉ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ etc. are used.

  When the battery of the present invention is an alkaline battery, an alkaline aqueous solution (for example, lithium hydroxide aqueous solution, water, etc.) is used as the electrolytic solution (the electrolytic solution injected into the battery and the electrolytic solution added to the gelled negative electrode). An aqueous potassium oxide solution, an aqueous sodium hydroxide solution, or the like can be used.

<Separator>
As the separator, either a microporous resin film or a resin nonwoven fabric can be used. Examples of the material include polyolefins such as PE, PP, and polymethylpentene, and as heat resistance, fluororesin such as tetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA); PPS; polyether ether ketone ( PEEK); PBT and the like. Moreover, you may comprise a separator by laminating | stacking two or more microporous resin films and resin nonwoven fabrics of the said material, or laminating | stacking two or more microporous resin films or resin nonwoven fabrics.

  The battery of the present invention can be applied to various uses in which conventionally known primary batteries and secondary batteries are used.

  Hereinafter, the present invention will be described in detail based on examples. However, the following examples do not limit the present invention. In this embodiment, a cylindrical lithium battery having an outer diameter of 17 mm and a height of 45 mm will be described as an example of a battery (nonaqueous electrolyte battery). In addition, "%" used in a present Example is a mass reference | standard (mass%) unless there is particular notice.

Example 1
The non-aqueous electrolyte battery of Example 1 is described in the order of [Preparation of positive electrode], [Preparation of negative electrode], [Preparation of wound electrode body], [Assembly of battery], [Post-treatment (preliminary discharge, aging)]. To do.

[Production of positive electrode]
First, a positive electrode mixture (in mass ratio, solid content: water content = 100: 30) was prepared by the following procedure. Carbon black having a BET specific surface area of 600 m ² / g: 3% and manganese dioxide (manufactured by Tosoh Corporation): 92% were mixed by a dry method using a planetary mixer for 5 minutes, and then water was added to a solid content of 20% ( Mass ratio) and mixed for 5 minutes. PVDF dispersion ("D-1" manufactured by Daikin Industries, Ltd.) is prepared in an amount corresponding to 5% of the solid content of the positive electrode mixture, diluted with the remaining water, and added to the mixture. And mixed for 5 minutes to obtain a positive electrode mixture.

Using the above positive electrode mixture, two rolls having a diameter of 250 mm, adjusting the roll temperature to 125 ± 5 ° C., press pressure: 7 ton / cm, roll interval: 0.4 mm, rotation speed: 10 rpm The sheet was rolled and rolled. The positive electrode mixture (preliminary sheet) that passed through the roll was dried at 105 ± 5 ° C. until the residual moisture was 2% or less. Next, the dried preliminary sheet was pulverized using a pulverizer. At this time, the preliminary sheet was pulverized until it became twice or more the original apparent volume. Most of the particle diameter after pulverization was 1 mm or less, and PVDF added as a binder was also cut into fibers having a length of 1 mm or less. The pulverized material was formed into a sheet again by a roll. The interval between the rolls was adjusted to 0.6 ± 0.05 mm, and a positive electrode mixture sheet was obtained by forming a sheet under the conditions of roll temperature: 125 ± 10 ° C., press pressure: 7 ton / cm, and rotation speed: 10 rpm. The obtained positive electrode mixture sheet has a thickness of 1.0 mm and corresponds to 5.9% of the inner diameter of the outer can. Moreover, the density of the positive mix sheet was 2.5 g / cm < ³ >, and the porosity was 42%. The positive electrode mixture sheet was cut to obtain an inner periphery positive electrode mixture sheet having a width of 37 mm and a length of 51 mm, and an outer periphery positive electrode mixture sheet having a width of 37 mm and a length of 62 mm.

The positive electrode current collector was produced as follows. First, a SUS316 plate having a thickness of 140 μm was used as a material constituting the metal plate, and an equilateral triangular protrusion having a side of 800 μm was formed on both sides of the steel plate in a scale shape as shown in FIGS. 3 and 4 in the width direction. At a pitch of 2 mm and a pitch of 2 mm in the longitudinal direction. The inclination angle a of the formed protrusion is 45 °, the height of the protrusion is about 0.5 mm, and the number of protrusions the current collector has is an area of 1 cm ^{2 on} one side of the current collector in a plan view of the current collector. There were 12 hits.

The positive electrode current collector is cut into a width of 34 mm and a length of 56 mm, and resistance welding is performed using a stainless steel ribbon having a thickness of 0.1 mm and a width of 3 mm as a positive electrode lead body at the center in the length direction. Attached by. Further, a carbon paste (manufactured by Nippon Graphite Co., Ltd.) was applied to the expanded metal so as not to crush the mesh, and then dried at a temperature of 105 ± 5 ° C. to obtain a positive electrode current collector. The coating amount of the carbon paste was set to 5 mg / cm ² after drying.

  Next, in a state where the positive electrode current collector is interposed between the positive electrode mixture sheet for the inner periphery and the positive electrode mixture sheet for the outer periphery, only one end in the length direction is fixed and the three parties are integrated. . Specifically, the positive electrode mixture sheet for the inner periphery and the positive electrode mixture sheet for the outer periphery are aligned with one end in the length direction, and the end of the positive electrode current collector is composed of two positive electrode mixture sheets. Set the two so that they do not protrude from one end, and in that state, press the 5mm part of the two positive electrode mixture sheets from the end where both are aligned, so that the three parties are integrated. did. Then, the two positive electrode mixture sheets and the positive electrode current collector were integrated with hot air at 250 ± 10 ° C. for 6 hours to obtain a sheet-like positive electrode having a width of 37 mm.

[Preparation of negative electrode (negative electrode precursor)]
The negative electrode has a width: 37 mm, a length: 170 mm, a thickness: 10 μm on a copper foil (negative electrode current collector), a width: 37 mm, a length: 87 mm, a thickness: 0.30 mm metal lithium foil, and a width: 37 mm. A metal lithium foil having a length of 50 mm and a thickness of 0.30 mm is disposed, and further, a width: 35 mm, a length: 85 mm, a thickness: 6 μm, a width: 35 mm, a length: 48 mm, and a thickness: A 6 μm aluminum foil was arranged. First, a negative electrode lead made of nickel having a width of 3 mm, a length of 20 mm, and a thickness of 0.1 mm was pressure-bonded to a metal lithium foil having a length of 50 mm. Thereafter, the two metal lithium foils are placed on the copper foil in a separated state, and the aluminum foil is placed on each of the two metal lithium foils to form a sheet-like negative electrode (lithium- A sheet-like negative electrode precursor before forming an aluminum alloy (hereinafter referred to as “sheet-like negative electrode” for convenience) was prepared.

[Production of wound electrode body]
Laminate a microporous polyethylene film ["Hypore" (trade name) manufactured by Asahi Kasei Co., Ltd.] having a width: 44 mm, a length: 170 mm, and a thickness: 20 μm, and a non-woven fabric having a width: 42 mm, a length: 170 mm, and a thickness: 20 μm. The separator was manufactured by heat welding at a position 65 mm from one end in the length direction of the microporous polyethylene film, shifted by 10 mm from the nonwoven fabric.

  And the separator was affixed on the copper foil of the sheet-like negative electrode through the adhesive tape. In addition, when affixing a separator to a negative electrode, the nonwoven fabric surface was made into the positive electrode side, and the heat welding part of the microporous film of a separator and a nonwoven fabric was included in the adhesion part with an adhesive tape. Next, centering on the heat-welded part between the microporous film of the separator and the nonwoven fabric, the separator was sandwiched between two winding cores having a diameter of 3.5 mm and wound once. Next, after winding the negative electrode together with the separator once, the side on which the sheet-like positive electrode was fixed was placed on the winding core side and wound. After winding, the copper foil covered the outermost periphery. The electrode winding body was obtained by the above.

[Battery assembly]
A non-aqueous electrolyte battery having the structure shown in FIG. 1 was assembled using the electrode winding body. A polypropylene insulating plate having a thickness of 0.2 mm is inserted into the inner bottom portion 2a of the bottomed cylindrical outer can 2 made of nickel-plated iron can, and the electrode winding body 3 and the positive electrode lead body 15 are inserted thereon. Was inserted in a posture facing upward. The negative electrode lead body 16 of the electrode winding body 3 was resistance welded to the inner surface of the outer can 2, and the positive electrode lead body 15 was resistance welded to the lower surface of the terminal plate 10 after inserting the insulating plate 11. At this point, the insulation resistance was measured and it was confirmed that there was no short circuit.

As the electrolyte, a non-aqueous solution prepared by dissolving LiClO ₄ at a concentration of 0.5 mol / l in a mixed solvent of propylene carbonate and dimethoxyethane (volume ratio of 1: 2) was prepared, and this was used as an outer can. 3.5 ml was injected into 2. The injection was divided into three times, and the whole amount was injected while reducing the pressure in the final step. After the electrolyte solution is injected, the cover plate 8 is fitted into the upper opening of the outer can 2, and the inner peripheral portion of the opening end of the outer can 2 and the outer peripheral portion of the cover plate 8 are welded by laser welding. 2 openings were sealed.

[Post-treatment (preliminary discharge, aging)]
The sealed battery was pre-discharged with a resistance of 1Ω for 30 seconds, stored at 70 ° C. for 6 hours, then subjected to a secondary pre-discharge with a constant resistance of 1Ω for 1 minute, and lithium-aluminum on the separator-side surface of the sheet-like negative electrode. An alloy was formed. The battery after the preliminary discharge was aged at room temperature for 7 days, the open circuit voltage was measured to confirm that a stable voltage was obtained, and non-aqueous electrolysis with an outer diameter of 17.0 mm and a total height of 45.0 mm A liquid battery was obtained. The ratio of the negative electrode capacity to the positive electrode capacity of this nonaqueous electrolyte battery was 1.00.

Comparative Example 1
In producing the positive electrode, a non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that an expanded metal made of stainless steel (SUS316) was used as the positive electrode current collector.

  Regarding the nonaqueous electrolyte batteries of Example 1 and Comparative Example 1, those that were not discharged after production, those that were discharged to a discharge depth of 40% at a discharge current of 1 mA in an environment at 20 ° C., and those that were discharged in the same environment Five were discharged each with a current discharged to a discharge depth of 80%. These batteries were stored at 80 ° C. for 60 days, and the internal resistance before and after that was measured to obtain an average value for five batteries. These results are shown in Table 1.

  As shown in Table 1, it can be confirmed that the nonaqueous electrolyte battery of Example 1 can suppress the increase in internal resistance during high-temperature storage after the discharge has advanced, compared with the battery of Comparative Example 1. Thus, in the battery of Example 1, even in a state where the positive electrode mixture sheet was expanded by discharge, the positive electrode mixture layer and the current collector were in good contact, and winding looseness was suppressed, It can be confirmed that the increase in internal resistance is suppressed.

4 Sheet-like positive electrode 5 Separator 6 Sheet-like negative electrode 41 Positive electrode mixture layer (positive electrode mixture sheet)
42 Sheet-form positive electrode current collector 41a Protrusion

Claims (6)

A battery having an electrode winding body in which a sheet-like positive electrode and a sheet-like negative electrode are wound via a separator,
The sheet-like positive electrode is composed of a positive electrode mixture sheet containing a positive electrode active material, a conductive additive and a binder, and is bonded to one or both sides of a metal current collector,
The sheet-like positive electrode current collector has a protrusion on a surface thereof, and the protrusion penetrates into the sheet-like positive electrode mixture.   The battery according to claim 1, wherein the protrusions of the sheet-like positive electrode current collector are inclined in a direction opposite to the winding direction of the electrode winding body.   The battery according to claim 1, wherein a conductive material is applied to a surface of the current collector of the sheet-like positive electrode.   The battery according to claim 1, wherein the protrusions of the current collector of the sheet-like positive electrode are made of metal.   The battery according to any one of claims 1 to 4, wherein the current collector of the sheet-like positive electrode is a metal plate.   From the current collector side surface of the positive electrode mixture sheet to the position of 1/5 to 1/2 of the thickness of the positive electrode mixture sheet, the protrusions of the sheet positive electrode collector have protrusions in the positive electrode mixture sheet. The battery according to any one of claims 1 to 5.

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