WO2008059937A1

WO2008059937A1 - Method for manufacturing collector for nonaqueous secondary battery, method for manufacturing electrode for nonaqueous secondary battery, and nonaqueous secondary battery

Info

Publication number: WO2008059937A1
Application number: PCT/JP2007/072221
Authority: WO
Inventors: Takashi Nonoshita; Takuhiro Nishimura; Hitoshi Katayama; Masanori Sumihara; Seiichi Kato
Original assignee: Panasonic Corporation
Priority date: 2006-11-15
Filing date: 2007-11-15
Publication date: 2008-05-22
Also published as: KR20090082223A; KR101139639B1

Abstract

Intended is to improve the mechanical strength and the durability of a collector for a nonaqueous secondary battery, so that an active substance layer may be carried efficiently in a high adhesion on the surface of the collector. This improvement is achieved by using a pair of working means, which have surfaces pressed toward each other to form a pressing nip portion for allowing a sheet-shaped substance to pass therethrough and which have a plurality of recesses formed in at least one surface. A metal foil for the collector is subjected to a compressing treatment by passing it through the pressing nip portion of the working means so that a plurality of projections are formed on at least one surface of the collector metal foil by the partial plastic deformation caused according to the compressing treatment.

Description

Specification

Non-aqueous electrolyte secondary battery current collector manufacturing method, non-aqueous electrolyte secondary battery electrode manufacturing method, and non-aqueous electrolyte secondary battery

Technical field

The present invention relates to a method for producing a current collector for a non-aqueous electrolyte secondary battery, a method for producing an electrode for a non-aqueous electrolyte secondary battery, and a non-aqueous electrolyte secondary battery. More specifically, the present invention mainly relates to improvement of a current collector for a non-aqueous electrolyte secondary battery.

Background art

[0002] Lithium secondary batteries have a high potential and high capacity, and are relatively easy to reduce in size and weight. Therefore, their use as a power source for portable electronic devices has increased remarkably recently. Yes. A typical lithium secondary battery uses a carbonaceous material or the like capable of occluding and releasing lithium as a negative electrode active material, and lithium and a transition metal such as LiCoO as a positive electrode active material.

2

High potential and high capacity are realized by using a complex oxide of thium. However, as the functionality of portable electronic devices increases and power consumption continues to increase, lithium secondary batteries used as power sources are also expected to improve the characteristic deterioration associated with charge / discharge cycles.

[0003] An electrode that is a power generation element of a lithium secondary battery includes a current collector and an active material layer. The active material layer is generally formed by applying a mixture slurry on one side or both sides of a current collector and drying it, followed by press molding. The mixture slurry is prepared by mixing and dispersing a positive electrode active material or a negative electrode active material, a binder and, if necessary, a conductive material in a dispersion medium. Here, as one of the factors of the characteristic deterioration accompanying the charge / discharge cycle, there is a decrease in the binding force between the active material layer formed on the current collector surface and the current collector. In the lithium secondary battery, the electrode expands and contracts with the charge / discharge cycle, so that the binding force between the current collector and the active material layer is weakened, and the active material layer is separated from the current collector. Dropping occurs and the characteristics deteriorate.

[0004] In order to increase the binding force between the current collector and the active material layer, it is effective to increase the contact area between the current collector and the active material layer. For this purpose, the current collector surface is roughened. A method for forming the surface and a method for forming irregularities on the surface of the current collector have been proposed.

Current collector surface roughening methods include, for example, a method of etching the surface of the current collector by electrolysis, a method of depositing the same metal contained in the current collector by electrodeposition on the current collector surface, etc. Is mentioned.

[0005] As a method for forming irregularities on the surface of the current collector, for example, a method of forming fine irregularities on the surface by causing fine particles to collide with the surface of a rolled copper foil as a current collector at high speed (for example, a patent (Ref. 1) has been proposed. In Patent Document 1, although a current collector having random irregularities can be formed locally, a velocity distribution is generated in the fine particles ejected from the nozzle, so that irregularities are uniformly formed in the width direction and the longitudinal direction of the current collector. It ’s difficult.

[0006] Further, a method has been proposed in which a metal foil is irradiated with a laser beam to form a concave / convex surface with a 10-point average roughness of 0.5 to 10 lO ^ m (for example, see Patent Document 2). ing. In Patent Document 2, a laser beam is irradiated to locally heat a metal foil to evaporate the metal, thereby forming a recess. Then, it is possible to form irregularities on the entire surface of the metal foil by continuously irradiating the laser beam. However, since the laser beam is scanned linearly, the metal foil is locally heated to a temperature higher than the melting point of the metal foil to prevent the metal foil from wavy, wrinkled, warped, etc. It is difficult. In addition, when laser processing is performed on a metal foil with a thickness of 20 m or less, such as a current collector of a lithium secondary battery, there may be a problem that a hole is formed in the metal foil due to variations in laser output.

[0007] Further, a roller having an uneven surface and a roller having a hard rubber layer on the surface are brought into contact with each other so that the respective axes are parallel to each other, and the current collector is passed through the contact portion. And a method of forming irregularities on the current collector (see, for example, Patent Document 3). In Patent Document 3, irregularities are formed on the current collector in order to improve the output density of the lithium secondary battery without reducing the thickness of the active material layer. In Patent Document 3, since a roller having a hard rubber layer provided on the surface is used, even if a current collector is passed through a contact portion between the roller and the roller, plastic deformation hardly occurs.

[0008] In addition, in order to improve the binding force and electrical conductivity between the current collector and the active material layer, a current collector having specific irregularities has been proposed (see, for example, Patent Document 4). 20 (a) to 20 (e) are perspective views schematically showing the configuration of the current collector of Patent Document 4. FIG. Patent Document 4 current collector When a local part of one surface of the metal foil is depressed, the body has a partial force corresponding to the local part on the other surface, and irregularities that protrude outward from the other surface are regularly formed. It has been done. Such a current collector has sufficient mechanical strength. Furthermore, when an active material layer is formed on such a current collector, the thickness of the active material layer tends to be non-uniform, which adversely affects battery performance.

Furthermore, in Patent Documents !! to 4, when a concave portion is formed on one surface of a metal foil, a portion corresponding to the concave portion on the other surface is inevitably formed as a convex portion, forming irregularities. It is difficult to prevent the metal foil from wavy, wrinkled, warped, etc.

[0009] In addition, the current collector includes a current collector made of punch metal having an opening degree of 20% or less in which unevenness is formed by embossing, and an active material layer filled in the recess of the current collector. There has been proposed an electrode in which a part is exposed or an electrode in which an active material adheres to a convex part (see, for example, Patent Document 5). FIG. 21 is a longitudinal sectional view schematically showing the configuration of the electrodes 101 to 103 of Patent Document 5. An electrode 101 shown in FIG. 21 (a) includes a current collector 110 having irregularities formed thereon and an active material layer 111 filled in a concave portion 110b of the current collector 110, and a convex portion 30a of the current collector 110. The active material layer 11 1 also adheres to the surface. In the electrodes 102 and 103 shown in FIGS. 21 (b) and 21 (c), the convex portions 120a and 130a of the current collectors 120 and 130 are exposed, respectively. In Patent Document 5, since unevenness is formed by embossing a punch metal having an opening degree of 20% or less, the obtained current collector does not have sufficient mechanical strength. This may cause inconveniences such as electrode breakage.

[0010] In addition, an electrode is proposed that includes a current collector and an active material layer and has a value of (surface roughness Ra of active material layer)-(surface roughness Ra of current collector) of 0 .; 1 m or more (For example, see Patent Document 6). Usually, when a thin film of an active material is formed on the surface of the current collector by a vacuum deposition method or the like, a thin film having substantially the same surface roughness as that of the current collector surface is obtained. On the other hand, in Patent Document 6, the surface roughness of the thin film is adjusted to the specific value by subjecting the thin film formed by an ordinary method to processing such as sand blasting and surface polishing. This is trying to relieve the expansion stress of the active material. Although the technique of Patent Document 6 is effective to some extent in preventing cracking of the active material, a thin film of the active material is formed on the entire surface of the current collector. Therefore, peeling of the thin film from the current collector, electrode deformation, and the like are likely to occur. As a result, the charge / discharge cycle characteristics deteriorate.

Patent Document 1: Japanese Patent Application Laid-Open No. 2002-79466

Patent Document 2: JP 2003-258182 A

Patent Document 3: JP-A-8-195202

Patent Document 4: Japanese Patent Laid-Open No. 2002-270186

Patent Document 5: Japanese Patent Laid-Open No. 2005-32642

Patent Document 6: Japanese Patent Application Laid-Open No. 2002-279972

Disclosure of the invention

Problems to be solved by the invention

[0012] An object of the present invention is to provide a nonaqueous electrolyte secondary battery collection having a high mechanical strength in which a plurality of convex portions capable of efficiently supporting an active material layer are formed on at least one surface without being subjected to compression processing. An object of the present invention is to provide a method for manufacturing an electric body.

Another object of the present invention is to provide a method for producing an electrode for a nonaqueous electrolyte secondary battery comprising a current collector obtained by the method for producing a current collector for a nonaqueous electrolyte secondary battery of the present invention and an active material layer. It is to be.

A further object of the present invention is to provide a nonaqueous electrolyte secondary battery including an electrode produced by the method for producing an electrode for a nonaqueous electrolyte secondary battery of the present invention.

Means for solving the problem

[0013] The present invention provides a pair of processing means provided so as to form a press-fitting two-ply portion through which a surface can be pressed against each other and through which a sheet-like material can pass, and a plurality of recesses formed on at least one surface. A non-aqueous electrolyte secondary that forms a plurality of convex portions on at least one surface of the current collector metal foil by passing the metal foil for current collector through the pressure-welded ep portion of the processing means and compressing the current collector metal foil. The present invention relates to a method for producing a battery current collector.

[0014] It is preferable that the surface roughness of the tip surface of the convex portion is substantially the same as the surface roughness of the current collector metal foil before compression processing.

The cross section of the recess in the direction perpendicular to the processing means surface has a tapered shape in which the width of the cross section in the direction parallel to the processing means surface gradually decreases from the processing means surface toward the bottom of the recess. Preferably it is.

It is preferable to compress the convex portion so that the volume of the convex portion is equal to or less than the volume of the internal space of the concave portion.

It is preferable to compress the convex portion so that the volume of the convex portion is 85% or less of the volume of the internal space of the concave portion.

[0015] In the processing means in which a plurality of concave portions are formed on the surface, the boundary between the concave portion and the surface of the processing means is preferably a curved surface.

It is preferable that the curved surface at the boundary between the concave portion and the surface of the processing means is formed by forming the concave portion by laser processing and removing the bulge at the boundary between the concave portion and the surface of the processing means.

It is preferable to remove the bumps by polishing with diamond particles having an average particle size of 30,1 m or more and less than 53,1 m.

[0016] Preferably, a plurality of grooves having a width of 1 μm or less and a depth of 1 μm or less are formed at the boundary between the recess and the surface of the processing means.

It is preferable to form grooves by polishing with diamond particles having an average particle size of 5 m or less.

[0017] Preferably, the pair of processing means is a pair of rollers, and a recess is formed on the surface of at least one of the rollers.

It is preferable that a surface coating layer containing cemented carbide, alloy tool steel, or chromium oxide is formed on the surface of the roller where the recess is formed and on the surface facing the inner space of the recess.

A protective layer containing an amorphous carbon material is preferably formed on the surface of the surface coating layer.

The surface coating layer and the protective layer are formed by a physical vapor deposition method using sputtering, a physical vapor deposition method using ion implantation, a chemical vapor deposition method using thermal evaporation, and a chemistry using plasma deposition. Preferably, it is formed by at least one gas phase growth method selected from the group consisting of chemical vapor deposition methods.

[0018] At least one roller force is a roller provided with a ceramic layer on the surface, A recess is formed on the surface!

It is preferable to apply a lubricant to the surface of the roller or current collector metal foil and dry it.

The lubricant preferably contains a fatty acid.

[0019] The present invention also includes a base member made of a current collector metal foil and a plurality of convex portions formed so as to extend outward from at least one surface of the base member. The present invention relates to a current collector for a non-aqueous electrolyte secondary battery in which the boundary between the surface of the substrate portion and the convex portion is a curved surface.

[0020] Further, the present invention provides a current collector for a nonaqueous electrolyte secondary battery produced by any one of the above methods for producing a current collector for a nonaqueous electrolyte secondary battery, or the above-mentioned nonaqueous electrolyte secondary battery. The present invention relates to a method for producing an electrode for a nonaqueous electrolyte secondary battery in which a positive electrode active material or a negative electrode active material is supported on the surface of a current collector.

It is preferable to support the positive electrode active material or the negative electrode active material on the convex surface of the current collector for the non-aqueous electrolyte secondary battery.

[0021] The present invention is a non-aqueous electrolyte secondary battery containing a positive electrode, a negative electrode, a separator and a non-aqueous electrolyte,

At least one of the positive electrode and the negative electrode relates to a non-aqueous electrolyte secondary battery that is an electrode manufactured by the method for manufacturing an electrode for a non-aqueous electrolyte secondary battery.

The invention's effect

[0022] According to the method for producing a current collector for a non-aqueous secondary battery of the present invention, since the convex portions are formed without being subjected to compression processing, the mechanical strength is improved and the current collector is rich in durability. The body is obtained. Further, the convex portion is formed by plastic deformation without being subjected to compression processing. In addition, since the tip surface of the convex part is formed with almost no influence of the compression process and the plastic deformation accompanying it, it has almost the same surface roughness as the current collector metal foil before the compression process. The current collector having such a convex portion is further improved in mechanical strength and thus durability, and has a very strong adhesion to the active material layer when the active material layer is supported.

Further, in a current collector including a base material part and a plurality of convex parts formed so as to extend outward from at least one surface of the base material part, the surface of the base material part and the convex part By making the boundary part a curved surface, the mechanical strength and durability of the current collector are further improved. further In addition, the convex portions can be formed at a lower pressure during the compression processing, and the releasability of the current collector from the processing means after the compression processing can be improved.

Brief Description of Drawings

FIG. 1 is a longitudinal sectional view schematically showing a method for producing a current collector which is one embodiment of the present invention.

FIG. 2 is a longitudinal sectional view schematically illustrating plastic deformation of a current collector metal foil accompanying compression processing.

FIG. 3 is a side view schematically showing the configuration of the current collector manufacturing apparatus.

4 is an enlarged perspective view showing a configuration of a main part of the current collector manufacturing apparatus shown in FIG.

FIG. 5 is a drawing showing a configuration of a roller used for compression processing. FIG. 5 (a) is a perspective view showing the appearance of the roller. FIG. 5 (b) is an oblique view showing an enlarged surface area of the roller shown in FIG. 5 (a).

FIG. 6 is a longitudinal sectional view schematically showing a method of manufacturing a current collector of another form which is one of the embodiments of the present invention.

FIG. 7 is a longitudinal sectional view schematically showing the structure of a current collector obtained by the method for producing a current collector for a non-aqueous electrolyte secondary battery of the present invention.

8 is a longitudinal sectional view schematically showing a method for manufacturing the current collector shown in FIG.

FIG. 9 is a drawing showing the configuration of another form of roller used for compression processing. Fig. 8 (a) is a perspective view showing the appearance of the mouth roller. FIG. 8 (b) is an enlarged perspective view showing the surface area of the roller shown in FIG. 8 (a). FIG. 8 (c) is an enlarged perspective view showing a recess formed on the roller peripheral surface shown in FIG. 8 (b).

FIG. 10 is a longitudinal sectional view schematically showing a configuration of a current collector of another embodiment obtained by the method for producing a current collector for a non-aqueous electrolyte secondary battery of the present invention.

FIG. 11 is a longitudinal sectional view schematically showing a method for manufacturing the current collector shown in FIG. 10.

FIG. 12 is a partially exploded perspective view schematically showing a configuration of a wound non-aqueous electrolyte secondary battery which is one embodiment of the present invention.

FIG. 13 is a longitudinal sectional view schematically showing a configuration of a laminated nonaqueous electrolyte secondary battery which is one embodiment of the present invention. FIG. 14 is a drawing schematically showing a configuration of a current collector obtained in Example 5. Figure 14 (a) is a perspective view. FIG. 14 (b) is a longitudinal sectional view.

FIG. 15 is a drawing schematically showing a configuration of a current collector obtained in Example 6. FIG. 15 (a) is a perspective view. Fig. 15 (b) is a longitudinal sectional view.

FIG. 16 is a drawing schematically showing a configuration of a current collector obtained in Example 24. Figure 16 (a) is a perspective view. FIG. 16 (b) is a longitudinal sectional view.

FIG. 17 is a drawing schematically showing a configuration of a current collector obtained in Example 25. Figure 17 (a) is a perspective view. FIG. 17 (b) is a longitudinal sectional view.

FIG. 18 is an electron micrograph of a cross section of the current collector obtained in Example 1.

FIG. 19 is an electron micrograph of a cross section of a current collector obtained in Comparative Example 1.

FIG. 20 is a perspective view schematically showing a configuration of a current collector of the prior art.

FIG. 21 is a longitudinal sectional view schematically showing a configuration of a conventional electrode.

[0024] According to the method for producing a current collector for a non-aqueous secondary battery of the present invention, the step of forming a convex portion on the surface of the current collector metal foil, the electrode active material is supported on the convex portion of the current collector In such a process, it is possible to prevent local deformation, stagnation, warping, cutting and the like of the current collector metal foil and current collector. At the same time, the electrode active material is supported on the convex part of the current collector, and the electrode active material is prevented from falling off the current collector in the process of manufacturing the electrode and slitting the electrode to a predetermined width. it can. Therefore, a highly reliable non-aqueous electrolyte secondary battery is finally obtained.

BEST MODE FOR CARRYING OUT THE INVENTION

[0025] [Method for producing current collector for non-aqueous electrolyte secondary battery]

The method for producing a current collector for a non-aqueous electrolyte secondary battery according to the present invention (hereinafter simply referred to as “current collector production method”) passes the current collector metal foil through the pressure nip portion of a pair of processing means. It is characterized by performing compression processing. More specifically, by adopting the above-described configuration and causing partial plastic deformation on the surface of the current collector metal foil, the tip surface is formed with a convex portion that is hardly affected by compression processing and plastic deformation. It is characterized by.

Here, the pair of processing means is provided so as to form a press-fitting dip portion through which a sheet-like material can pass through pressure contact with each other, and a plurality of concave portions are formed on at least one surface. A pair of processing means. As the pair of processing means, a pair of rollers is preferable. The pair of rollers has a plurality of recesses formed on at least one surface. In the compression processing of the present invention, for example, the current collector metal foil is passed through the press nip portion of a pair of rollers, the current collector metal foil is mechanically pressed, and the current collector metal foil is partially processed. This is done by plastic deformation. When a current collector having a convex portion on the surface is produced by performing compression processing using a pair of rollers, peeling of the convex portion from the current collector can be almost certainly prevented. In addition, a current collector having a convex portion on the surface can be manufactured at low cost with high productivity.

According to the method for producing a current collector of the present invention, a current collector for a non-aqueous electrolyte secondary battery in which a plurality of convex portions are formed on one surface in the thickness direction (hereinafter simply referred to as “current collector”) Is obtained.

FIG. 1 is a longitudinal sectional view schematically showing compression processing of a current collector metal foil 10 which is one embodiment of the present invention. FIG. 2 is a longitudinal sectional view schematically illustrating plastic deformation of the current collector metal foil 10 accompanying compression processing. 3 is a side view schematically showing the configuration of the current collector manufacturing apparatus 35. FIG. FIG. 4 is an enlarged perspective view showing a configuration of a main part (processing means 37) of the current collector manufacturing apparatus 35 shown in FIG. FIG. 5 is a diagram showing the configuration of the roller 4 used for compression processing. FIG. 5A is a perspective view showing the appearance of the roller 4. FIG. 5 (b) is an enlarged perspective view showing the surface region 4x of the roller 4 shown in FIG. 5 (a).

The current collector manufacturing method of the present invention is performed using, for example, a current collector manufacturing apparatus 35 shown in FIG. The current collector manufacturing apparatus 35 includes metal foil supply means 36, processing means 37, and current collector winding means 38.

Specifically, the metal foil supply means 36 is a metal foil supply roller. The metal foil supply roller is pivotally supported by a support means (not shown) so as to be rotatable around the axis. Metal foil supply A metal foil 10 for current collector is wound around the peripheral surface of the roller. The current collector metal foil 10 is supplied to the press-fitting dip portion 6 of the processing means 37.

[0028] The current collector metal foil 10 is a metal foil made of a metal material that does not cause an electrochemical reaction with lithium. When the current collector 1 for the negative electrode is produced from the metal foil 10 for current collector, examples of the metal foil 10 for current collector include copper, nickel, iron, and an alloy containing at least one of these. The metal foil etc. which consist of etc. can be used. Among these, a metal foil made of copper or a copper alloy is preferable. Examples of copper alloys include zinc-containing copper, tin-containing copper, and silver-containing Examples thereof include precipitation hardening alloys such as copper, zirconium-containing copper, chromium copper, tellurium copper, titanium copper, beryllium copper, iron-containing copper, phosphorus-containing copper, and aluminum copper, and composite alloys of two or more of these. Examples of copper and copper alloy metal foils include electrolytic copper foil, electrolytic copper alloy foil, rolled copper foil, copper alloy foil, rolled copper alloy foil, and a foil that has been subjected to a surface roughening treatment. The thickness of the metal foil for the negative electrode current collector is not particularly limited, but is preferably about 5 to 100 m.

[0029] When the current collector 1 for the positive electrode is produced from the metal foil 10 for the current collector, the metal foil for the current collector is used.

As the metal 10, for example, a metal foil made of aluminum, aluminum alloy, stainless steel, titanium, or the like can be used. The thickness of the metal foil for the positive electrode current collector is not particularly limited but is preferably about 5 to 100 in. Of course, these metal foils may be roughened.

The processing means 37 includes rollers 4 and 5 as shown in FIG. 3 and FIG. The rollers 4 and 5 are pressed against each other so that their axes are parallel to each other, thereby forming a press-contacting two-ply portion 6. A sheet-like object such as a current collector metal foil 10 can pass through the pressure-welding nipping portion 6. Each of the rollers 4 and 5 is rotatably supported by a support means (not shown), and is rotatably provided around an axis line by a drive means (not shown). Both rollers 4 and 5 may be drive rollers, or one may be a drive roller and the other may be a driven roller that rotates as the drive roller rotates. By rotating the rollers 4 and 5, the current collector metal foil 10 is guided to the inlet force of the pressure welding two-pipe part 6 and the outlet, and the current collector metal foil 10 is compressed and processed as shown in FIG. The current collector 1 shown in (c) is obtained.

The current collector 1 includes a base material portion 2 and a plurality of convex portions 3. The base material portion 2 is a plate-like portion in which the current collector metal foil 10 is compressed in the thickness direction. The convex part 3 is a protruding part formed so as to extend outward from the one surface 2 a of the base part 2. The convex part 3 is formed without being subjected to compression.

[0032] The roller 4 is a roller having a plurality of recesses 4a formed on the peripheral surface. The roller 4 forms the recess 4a on a recess forming roller made of, for example, one or more metal materials selected from the group consisting of various metals and alloys, preferably stainless steel, iron hardened steel, and the like. You can make it. A coating layer containing cemented carbide or alloy tool steel may be provided on the peripheral surface of the recess forming roller. By forming such a coating layer, the surface hardness of the finally obtained roller 4 is further increased. Therefore, when the current collector metal foil 10 is subjected to compression processing, the shape of the formed protrusion 3 varies. Can be suppressed.

[0033] Further, a coating layer containing cemented carbide or chromium oxide may be provided on the peripheral surface of the recess forming roller. Such a coating layer has the effect of relaxing resistance such as frictional force and stress under pressure. Therefore, when the roller 4 made of the concave forming roller provided with such a coating layer is used, the resistance generated between the roller 4 and the current collector metal foil 10 during the compression process is reduced. As a result, after the compression process, the releasability of the current collector 1 from the roller 4 is improved, process management is facilitated, the defective product rate is reduced, and this is industrially advantageous. In addition, since such a coating layer is firmly bonded to the recess forming roller, it is industrially advantageous in this respect that the coating layer hardly peels off even if it is repeatedly used.

[0034] Further, a protective layer containing an amorphous carbon material may be provided on the surface of the coating layer containing cemented carbide or chromium oxide. As a result, the surface hardness of the finally obtained roller 4 is further improved, the resistance generated between the roller 4 and the current collector metal foil 10 during compression processing is reduced, and the current collector after compression processing is The improvement in releasability from 1 roller 4 becomes even more remarkable.

[0035] The various coating layers and protective layers described above include, for example, physical vapor deposition using sputtering, physical vapor deposition using ion implantation, chemical vapor deposition using thermal evaporation, It is preferably formed by a vapor deposition method such as a chemical vapor deposition method using plasma deposition. Thereby, the release property of the current collector 1 from the roller 4 after the compression processing can be improved.

Furthermore, a coating layer made of a ceramic such as tungsten carbide (WC) or titanium nitride (TiN) may be provided on the peripheral surface of the recess forming roller. As a result, the surface hardness of the finally obtained roller 4 can be increased, and variations in the shape of the convex portion 3 formed by plastic deformation can be suppressed without being subjected to compression processing.

In the present invention, the recess 4a may be formed in the various coating layers or protective layers described above.

[0037] The recess 4a is formed by, for example, etching, sandblasting, electric discharge machining, laser machining, or the like. Can be formed. Among these, laser processing is preferable. According to the laser processing, the minute recesses 4a and the array pattern of the recesses 4a having dimensions on the order of several orders can be formed almost accurately. Examples of the laser used for laser processing include a carbon dioxide gas laser, a YAG laser, and an excimer laser. Among these, YAG laser is preferable. When laser processing is performed, the edge of the opening of the recess 4a on the circumferential surface of the roller 4 is raised. Even if it uses as it is, without removing the protrusion of the roller 4, the electrical power collector 1 is obtained. Further, it may be used after removing the protrusions of the roller 4 by polishing or the like.

[0038] The arrangement pattern of the recesses 4a on the circumferential surface of the roller 4 is as follows in the present embodiment. As shown in FIG. 5 (b), a row in which a plurality of recesses 4 a are connected at a pitch Pa in the longitudinal direction of the roller 4 is defined as one row unit 7. The plurality of row units 7 are arranged at a pitch Pb in the circumferential direction of the roller 4. The pitch Pa and the pitch Pb can be set arbitrarily. In the circumferential direction of the roller 4, one row unit 7 and the adjacent row unit 7 are arranged so that the recess 4 a is displaced in the longitudinal direction of the roller 4. In the present embodiment, the displacement in the longitudinal direction of the recess 4a is 0.5 · 5 Pa. The present invention is not limited to this, and an arbitrary setting is possible. In the present embodiment, the shape of the opening of the recess 4a on the circumferential surface of the roller 4 is substantially circular, but is not limited to this. For example, it is substantially elliptical, substantially rectangular, substantially rhombus, or substantially square. A substantially regular hexagonal shape or a substantially regular octagonal shape may be used.

[0039] Further, in the cross section of the recess 4a in the direction perpendicular to the circumferential surface of the roller 4, the width in the direction parallel to the circumferential surface of the roller 4 gradually decreases from the circumferential surface of the roller 4 toward the bottom of the recess 4a. It preferably has a tapered shape. This improves the releasability of the current collector 1 from the roller 4 after completion of the compression process.

[0040] On the peripheral surface of the roller 4 and the surface facing the inner space of the recess 4a, a covering layer containing cemented carbide, a coating layer containing alloy tool steel, a coating layer containing chromium oxide, an amorphous You may form 1 or 2 or more, such as a protective layer containing a carbon material. As a result, the same effects as those obtained by forming the coating layer and the protective layer on the recess forming roller can be obtained. In addition, the same effects as described above can be obtained by forming these coating layers and protective layers by the same physical vapor deposition method and chemical vapor deposition method as described above. According to these vapor phase growth methods, the coating layer and the protective layer are evenly applied to the surface facing the inner space of the recess 4a. Can be formed. In addition, materials such as cemented carbide contain cobalt as a binder, and when the current collector metal foil 10 contains copper, the affinity between cobalt and copper is high, so a copper roller This is effective in preventing adhesion to the inner surface of the four peripheral surfaces and the recess 4a.

[0041] Tungsten carbide is provided on the circumferential surface of the roller 4 and the surface facing the internal space of the recess 4a.

You may form the coating layer which consists of ceramics, such as (WC) and titanium nitride (TiN). As a result, the surface hardness of the roller 4 is improved, and the variation in the shape of the convex portion 3 due to plastic deformation accompanying compression processing is extremely reduced.

The roller 5 may be a roller having a smooth or flat peripheral surface, preferably a metal roller having a smooth or flat peripheral surface.

The pressure contact pressure of the rollers 4 and 5 is not particularly limited, but is preferably about 8 kN to about 15 kN per lcm of the current collector metal foil 10.

[0042] Further, when the current collector metal foil 10 is compressed by the processing means 37, a lubricant may be applied to at least one of the roller 4 and the current collector metal foil 10. The lubricant is applied to the circumferential surface of the roller 4 or the surface of the current collector metal foil 10 and dried. Thereby, the resistance force generated between the roller 4 and the current collector metal foil 10 during compression can be reduced, and the releasability of the current collector 1 from the roller 4 is further improved. Furthermore, the lubricant preferably contains a fatty acid. Of the fatty acids, myristic acid, which is preferable to saturated fatty acids, is particularly preferable. The fatty acid is preferably used in the form of a solution. As the solvent for dissolving the fatty acid, a solvent that can dissolve the fatty acid and easily volatilizes by drying is preferable. For example, a low-boiling solvent such as methanol or ethanol can be used. By applying and drying the fatty acid, the resistance force, especially the frictional force, generated during the compression process is further reduced, the elongation in the longitudinal direction of the current collector metal foil 10 is suppressed, and the original current collector metal Protrusions 3 that substantially retain the crystal structure of foil 10 are stably formed. As a result, peeling of the convex portion 3 from the base material portion 2 is remarkably suppressed.

[0043] The partial plastic deformation of the current collector metal foil 10 by the processing means 37 will be described with reference to Figs. FIG. 1A is a longitudinal sectional view showing a state immediately after the current collector metal foil 10 is supplied to the press-contact nip 6 of the processing means 37. Fig. 1 (b) shows a state in which plastic deformation is progressing on one surface of the current collector metal foil 10 at the pressure-welded ep portion 6. It is a longitudinal cross-sectional view. FIG. 1 (c) is a longitudinal sectional view of the current collector 1 after passing through the press-fitting nipping portion 6.

Fig. 2 shows the progress of plastic deformation shown in Fig. 1 (b) in three stages.

[0044] In the process shown in Fig. 1 (a), the current collector metal foil 10 has a film thickness t at the inlet of the pressure-welding nipping portion 6.

have. The current collector metal foil 10 is pressed in contact with the surfaces of the rollers 4 and 5.

0

In the step shown in FIG. 1 (b), the current collector metal foil 10 is pressed in the thickness direction. The surface of the current collector metal foil 10 is a non-contact surface 4b facing the recess 4a of the roller 4 and a contact surface 4c that exists around the non-contact surface 4b and contacts the flat portion of the peripheral surface of the roller 4. And divided. The contact surface 4c is compressed in the thickness direction, and the base material portion 2 is formed. The thickness of the base material part 2 is t. t is smaller than On the other hand, since the non-contact surface 4b is not subjected to pressure, the contact surface 4c

Ten

Plastic deformation occurs as it is compressed. As a result, the non-contact surface 4b rises toward the bottom of the recess 4a in the space of the recess 4a, and the projection 3 is formed. In other words, the convex portion 3 is not subjected to compression processing by pressure, and is formed by plastic deformation accompanying compression processing. Further, the non-contact surface 4 b becomes the tip surface of the convex portion 3. The tip surface of the convex portion 3 is not subjected to any compression processing, and therefore has almost the same surface roughness as the surface of the original current collector metal foil 10.

The progress of plastic deformation in the step shown in FIG. 1 (b) will be described in more detail based on FIG.

In the step shown in FIG. 2 (a), the current collector metal foil 10 is supplied to the pressure-welding nipping portion 6. At this time, the current collector metal foil 10 has a thickness t. Metal foil for current collector 10 rollers 4 recesses

0

In the portion 4b facing the portion 4a, stress is applied in the directions of the arrows lla and lib, that is, from the inside of the current collector metal foil 10 toward the recess 4a. As a result, plastic deformation starts to occur in the facing portion 4a.

In the step shown in FIG. 2 (b), the plastic deformation of the non-contact surface 4b proceeds, and the non-contact surface 4b rises toward the bottom of the concave portion 4a to form the convex portion 3x. The volume of the protrusion 3x occupies about 50% of the space volume inside the recess 4a. Since the tip surface of the convex portion 3x is not compressed, it has substantially the same surface state as the original metal foil 10 for current collector. Stresses 12a and 12b that push the convex portion 3x further toward the bottom of the concave portion 4a are added to the convex portion 3x. As a result, plastic deformation further proceeds along the inner wall surface of the recess 4a. In the step shown in FIG. 2 (c), the plastic deformation force of the facing portion 4b proceeds to the limit value of the space volume inside the concave portion 4a, the convex portion 3 is formed, and the current collector 1 is obtained.

Air is present inside the recess 4a. Therefore, when the plastic deformation of the facing portion 4b progresses, the air loses the escape field and is compressed, so that stress in the directions of the arrows 13a, 13b, and 14 is applied to the convex portion 3. . When such a stress becomes large, the base material part 2 may be deformed and the current collector 1 may be wrinkled or warped. In addition, the shape and size of the convex portion 3 may be uneven.

[0048] Therefore, the compression processing is preferably performed so that the volume of the convex portion 3 is preferably not more than the spatial volume inside the concave portion 4a, and more preferably not more than 85% of the spatial volume inside the concave portion 4a. As a result, the current collector 1 can be efficiently produced while suppressing the occurrence of defects such as wrinkles, warping, and cutting. Further, by performing compression processing so that the volume of the convex portion 3 is 85% or less of the space volume inside the concave portion 4a, the tip surface of the convex portion 3 is almost the same as the surface of the original metal foil 10 for current collector. The incidental effect that the convex portions 3 can be formed so as to have the same surface roughness is obtained. As a result, the active material layer is supported on the surface of the convex portion 3 and the electrode is manufactured and the electrode is slit to a predetermined width. Can be suppressed.

Now, the description returns to FIG. In the process shown in FIG. 1 (c), the convex portion 3 is formed without being subjected to compression processing. Therefore, in the direction in which the convex portion 3 extends, the front end surface of the convex portion 3 is free from processing distortion and the surface condition (surface roughness) and surface accuracy of the current collector metal foil 10 are maintained as they are. is doing. The side surface of the projection 3 also has a surface state close to the current collector metal foil 10. On the other hand, the concave portion 2a existing between the adjacent convex portions 3 is subjected to compression processing, and thus has a surface state different from that of the current collector metal foil 10. In addition, the maximum thickness t of the current collector 1 is a table in which the convex portion 3 is not formed in the thickness direction of the current collector 1.

2

This is the length from the surface to the tip surface of the protrusion 3. The maximum thickness t of current collector 1 is the current collector gold

2

The thickness of the metal foil 10 is larger than the thickness t. The relationship between thickness and maximum thickness t is

0 0 2

For example, the pressure can be adjusted by appropriately selecting the pressing force at the pressure-welding two-ply portion 6.

[0050] In the current collector 1 obtained by the roller processing method, there is no interface between the base material part 2 and the convex part 3, the crystal part has almost the same crystal state, and the convex part from the base material part 2 There is at least one continuous region over 3. A cross section of the current collector 1 in the thickness direction is observed with an electron microscope. Then, a region having substantially the same crystal state exists in at least a part of the cross section, and the region extends across both the base material portion 2 and the convex portion 3 and is connected without being interrupted. As long as observed with an electron microscope, there is no crystalline state showing the joint in this region. By adopting such a configuration, it is possible to remarkably prevent peeling of the convex portion 3 from the base material portion 2 and further peeling of the active material layer from the convex portion 3.

[0051] Returning to the description based on FIG. The current collector winding means 38 is specifically a current collector winding roller. The current collector winding roller is pivotally supported by a support means (not shown) so as to be rotatable around an axis. Further, the current collector winding roller is driven to rotate by a driving means (not shown). The current collector winding roller rotates and winds the current collector 1 formed by the processing means 37 on its peripheral surface.

According to the current collector manufacturing apparatus 35, the current collector metal foil 10 is compressed and partially plastically deformed, and the current collector 1 including the base material 2 and the plurality of convex portions 3 is obtained. Manufactured.

[0052] Further, by performing compression processing using the current collector manufacturing apparatus 35 having the above-described configuration, the surface of the current collector metal foil 10 is linear and has a very small area. Since pressurization is possible, sufficient compression processing can be performed even if the pressurization capacity is relatively small. Therefore, the current collector manufacturing apparatus 35 can be downsized. Further, by using the current collector manufacturing apparatus 35, it is possible to continuously form the convex portions 3 on the surface of the strip-shaped current collector metal foil 10, which is industrially advantageous.

FIG. 6 is a vertical cross-sectional view schematically showing a method for manufacturing a current collector of another form, which is one embodiment of the present invention. FIG. 6A is a longitudinal cross-sectional view showing a state immediately after the current collector metal foil 10 is supplied to the pressure contact ep portion 6. FIG. 6B is a longitudinal sectional view showing a state in which the plastic deformation of the surface of the current collector metal foil 10 is proceeding in the pressure contact ep portion 6. FIG. 6 (c) is a longitudinal sectional view of the current collector 1 after passing through the pressure epping section 6. The method for manufacturing the current collector 15 shown in FIG. 6 is similar to the method for manufacturing the current collector 1 shown in FIG. 1, and the corresponding parts are denoted by the same reference numerals and description thereof is omitted.

The manufacturing method of the current collector 15 shown in FIG. 6 is characterized in that as a pair of processing means, those having recesses formed on the surface of both processing means are used, and otherwise, the current collector shown in FIG. It can be carried out in the same manner as the manufacturing method of body 1. The method for manufacturing the current collector 15 is performed, for example, using a current collector manufacturing apparatus in which a roller 4 is mounted instead of the roller 5 in the current collector manufacturing apparatus 35 shown in FIG. Based on FIG. 6, a method for manufacturing the current collector 15 will be described.

In the step shown in FIG. 6 (a), the current collector metal foil 10 has a film thickness t at the inlet of the pressure-welding nipping portion 6. The current collector metal foil 10 is pressed against the peripheral surfaces of the two rollers 4.

0

The Both sides in the thickness direction of the current collector metal foil 10 are divided into a non-contact surface 4b that faces the recess 4a of the roller 4 and does not contact the peripheral surface of the roller 4, and a contact surface 4c that contacts the peripheral surface of the roller 4. The The contact surface 4c exists around the non-contact surface 4b. The two rollers 4 are arranged and pressed so that a plurality of recesses 4a formed on the peripheral surface face each other.

In the step shown in FIG. 6 (b), the contact surface 4c is compressed, and the base material portion 16 is formed. The thickness of the base material portion 16 is t. t is smaller than In contrast, the non-contact surface 4b is not pressurized.

3 3 0

Therefore, plastic deformation occurs as the contact surface 4c is compressed. As a result, the non-contact surface 4b rises toward the bottom of the recess 4a in the space of the recess 4a, and the protrusions 17x and 17y are formed. That is, the convex portions 17x and 17y are not subjected to compression processing by pressurization, and are formed by plastic deformation associated therewith. The non-contact surface 4b becomes the tip surface of the convex portions 17x and 17y with almost no influence of compression processing and plastic deformation, and has almost the same surface roughness as the current collector metal foil 10.

In the step shown in FIG. 6 (c), the current collector 15 is obtained. The convex portions 17x and 17y are formed without being subjected to compression processing. Therefore, in the direction in which the convex portions 17x and 17y extend, the surface of the tip of the convex portions 17x and 17y almost maintains the surface roughness and surface accuracy of the current collector metal foil 10 free from processing strain. The side surfaces of the protrusions 17x and 17y are not subjected to compression processing, but are affected by plastic deformation, and thus have a surface roughness close to that of the current collector metal foil 10. On the other hand, since the surface of the base material portion 16 existing between the adjacent convex portions 17x and 17y is subjected to compression processing, it has a surface state different from that of the current collector metal foil 10. In addition, the maximum thickness t of current collector 1 is the convex portions 17x, 1 formed on both sides of current collector 1 in the thickness direction.

Four

7y is the length between the tip planes. The maximum thickness t of current collector 1 is the original metal foil for current collector 1

Four

It is larger than 0 thickness t. The relationship between the thickness and the maximum thickness t is, for example,

0 0 4

It can be adjusted by appropriately selecting the pressing force in the pressure-welding two-ply portion 6. [0057] [Current collector for non-aqueous electrolyte secondary battery]

FIG. 7 is a longitudinal sectional view schematically showing a configuration of a current collector 20 for a non-aqueous electrolyte secondary battery which is another embodiment of the present invention. FIG. 8 is a longitudinal sectional view schematically showing a method of manufacturing the non-aqueous electrolyte secondary battery current collector 20 shown in FIG. FIG. 8 (a) is a longitudinal sectional view showing a state immediately after the current collector metal foil 10 is supplied to the pressing ep portion 8. FIG. 8 (b) is a longitudinal sectional view showing a state in which the plastic deformation of the surface of the current collector metal foil 10 is proceeding in the pressure welding nip portion 8. FIG. 8C is a longitudinal sectional view of the current collector 20 after passing through the pressure nip 8. FIG. 9 is a drawing schematically showing the configuration of the roller 28 used in the manufacturing method shown in FIG. FIG. 9A is a perspective view showing the appearance of the roller 28. FIG. 9B is an enlarged perspective view showing the surface region 28 a of the roller 28. FIG. 9 (c) is an enlarged perspective view showing the configuration of the concave portion 29 formed on the circumferential surface of the roller 28. FIG.

The current collector 20 includes a base material portion 21 and a plurality of convex portions 22.

The current collector 20 can be manufactured by compressing the current collector metal foil 10 by a pair of processing means and generating partial plastic deformation, as with the current collector 1. The compression process is performed on one side of the current collector metal foil 10. Details of the compression processing will be described later.

When the current collector 20 is used as the negative electrode current collector, the current collector 20 is composed of the same material as the current collector metal foil 10 when the current collector 1 is used as the negative electrode current collector. Further, when the current collector 20 is used as the positive electrode current collector, the current collector 20 is made of the same material as the current collector metal foil 10 when the current collector 1 is used as the positive electrode current collector. .

[0059] The base material portion 21 is formed in a sheet shape, and the cross-sectional shape in the thickness direction is substantially rectangular. The thickness of the base material portion 21 is t. Thickness is not particularly limited, but preferably 5 111 ~; lOO ^ m

5 5

More preferably, it is 8-35 111. If the thickness of the base material portion 21 is less than 5 m, the mechanical strength of the current collector 20 may be insufficient, and the handleability of the current collector 20 at the time of electrode manufacture may be reduced, and the electrode at the time of battery charging It is easy to break. On the other hand, if the thickness of the base material portion 21 exceeds lOO ^ m, the mechanical strength of the current collector 20 is secured S, and the volume of the current collector 20 occupying the entire electrode increases, resulting in a high battery capacity. in some cases force ^s can not be sufficiently achieved reduction.

As will be described later, the surface 21a of the base material portion 21 is subjected to compression processing, so that the original current collecting It has a surface roughness different from that of the body metal foil 10.

[0060] The plurality of convex portions 22 are formed on one surface of the base material portion 21 in the thickness direction. The convex portion 22 is formed so as to extend from the surface of the base material portion 21 toward the outside of the base material portion 21. The convex portion 22 has a function of supporting the active material layer on at least a part of its surface, for example.

The convex portion 22 is formed by plastic deformation accompanying the compression processing of the base material portion 21 without being subjected to the compression processing. Further, the tip surface of the convex portion 22 is hardly affected by compression processing and plastic deformation. Therefore, the tip surface of the convex portion 22 has a surface roughness substantially equal to the surface of the original current collector metal foil 10. The tip surface of the convex portion 22 is a flat surface that is at the most distant portion from the base material portion 21 of the convex portion 22 in the extending direction or the protruding direction of the convex portion 22.

Further, two adjacent convex portions 22 are formed so as to be separated from each other with a gap. Therefore, in the cross section in the thickness direction of the current collector 20 shown in FIG. 7, the surface 21a of the base material portion 21 exists as a concave portion between two adjacent convex portions 22.

Further, the convex portion 22 has a taper-shaped cross section in the thickness direction of the current collector 20 (hereinafter simply referred to as “the cross section of the convex portion 22”). More specifically, the cross section of the convex portion 22 has a width in a direction parallel to the surface of the base material portion 21 from the surface of the base material portion 21 to the direction in which the convex portion 22 extends (hereinafter simply referred to as “cross-sectional width of the convex portion 22”) Have a tapered shape that gradually or continuously decreases. In the present embodiment, the cross section of the convex portion 22 is substantially trapezoidal. Since the convex portion 22 has a tapered shape, the releasability of the current collector 20 from the roller 28 is improved after the compression processing is completed, the deformation of the convex portion 22 is prevented, and the convex portion 22 is prevented. Variations in the shape of the can be minimized.

In the present embodiment, the shape of the convex portion 22 is not particularly limited as long as the shape of the convex portion 22 is a truncated cone and the cross section of the convex portion 22 has a taper shape. Further, in the present embodiment, the force in which the tip surface of the convex portion 22 is a plane substantially parallel to the surface of the base material portion 21 in the extending direction of the convex portion 22 is not limited thereto. For example, a plane that is not parallel to the surface of the base member 21, a surface hemisphere with irregularities, or a dome shape may be used. These shapes are effective for increasing the bonding strength between the convex portion 22 and the active material layer. [0063] In FIG. 7, the length of a perpendicular drawn from one point on the straight line indicating the tip surface of the convex portion 22 to the straight line indicating the surface where the convex portion 22 of the base material portion 21 is not formed is t. t, the original

6 6 The convex portion 22 is formed so as to be larger than the thickness t of the current collector metal foil 10. In addition

0

, T can also be defined as the maximum thickness of the current collector 20.

6

[0064] Further, the boundary 22a between the base material portion 21 and the convex portion 22 on the surface 21a of the base material portion 21 is formed of a curved surface. Here, the boundary 22a also includes the vicinity of the boundary 22a. By making the boundary 22a into a curved surface, even if a force acts on the convex portion 22, it becomes possible to disperse stress, and the mechanical strength of the current collector 20 increases. As a result, local stagnation and deformation of the current collector 20 can be prevented in the step of forming the convex portion 22 and the step of manufacturing the electrode by supporting the active material on the convex portion 22. Further, in the process of slitting the electrode to a predetermined width after manufacturing the electrode, it is possible to prevent the active material layer from being peeled off from the current collector 20 or partially dropped.

FIG. 8 is a longitudinal sectional view for explaining the method for manufacturing the current collector 20 as described above.

In the process shown in FIG. 8 (a), for example, the current collector manufacturing apparatus 35 shown in FIG. 5 has the same configuration except that the roller 28 shown in FIG. 9 is used instead of the roller 4. The metal foil 10 for current collector is compressed using the device.

As shown in FIGS. 9 (a) and 9 (b), the roller 28 has a plurality of recesses 29 formed on its peripheral surface. In the recess 29, as shown in FIG. 9 (c), an opening edge 29a on the circumferential surface of the roller 28 of the recess 29 is formed by a curved surface, and a plurality of grooves 29x are formed on the curved surface. The groove 29x is formed linearly in the direction from the circumferential surface of the roller 28 to the bottom of the recess 29. The width of the groove 29x is not particularly limited, but is preferably 1 m or less. The depth of the groove 29x is not particularly limited, but is preferably 1 m or less. Note that the depth of the groove 29x is the length in the direction of force from the surface of the opening edge 29a toward the axis of the roller 28.

[0066] The surface of the current collector metal foil 10 and the roller 28 during the compression processing of the current collector metal foil 10 by using the roller 28 in which the recess 29 having the opening edge 29a formed of a curved surface is formed. The stress such as resistance force and frictional force generated in the surface is reduced, and the releasability of the current collector 20 from the roller 28 after the compression processing is finished is improved. In addition, since the stress that partially plastically deforms the current collector metal foil 10 is gently and reliably applied, the convex portion 22 can be reliably formed. And processability is improved. As a result, local stagnation and deformation of the current collector 20 can be prevented, and variations in the shape and height of the convex portion 22 can be remarkably reduced and the convex portion 22 can be deformed. Protrusions 22 with uniform dimensions such as shape and height can be formed.

[0067] Also, by forming a plurality of grooves 29x in the opening edge 29a, the atmosphere remaining in the internal space of the recess 29, the peripheral surface of the roller 29 and / or the surface of the current collector metal foil 10 during compression processing The lubricant or the like applied to the surface is discharged from the inner space of the recess 29 to the outside through the groove 29x. As a result, in the internal space of the concave portion 29, the internal resistance that tends to inhibit the plastic deformation of the convex portion 22 is reduced. As a result, the plastic deformation of the convex portion 22 proceeds smoothly, variation in the shape and dimensions of the convex portion 22 is reduced, and local variation in the mechanical strength of the current collector 20 obtained is reduced. This effect is particularly remarkable when the width of the groove 29x is 1 μm or less and the depth is 1 μm or less. If the width or depth of the groove 29x is too large, the residual atmosphere, lubricant, etc. can be removed, but the plastic deformation of the convex portion 22 may not proceed sufficiently.

In addition, the arrangement pattern of the recesses 29 on the circumferential surface of the roller 28 is as follows in the present embodiment. As shown in FIG. 9B, a row in which a plurality of concave portions 29 are connected at a pitch Pc in the longitudinal direction of the roller 28 is defined as one row unit 33. The plurality of row units 33 are arranged with pitches Pd in the circumferential direction of the roller 28. Pitch Pc and pitch Pd can be set arbitrarily. In the circumferential direction of the roller 28, one row unit 33 and the adjacent row unit 33 are arranged so that the concave portion 29 is displaced in the longitudinal direction of the roller 28. In the present embodiment, the displacement of the concave portion 29 in the longitudinal direction is a force of 0.5 Pc. The present invention is not limited to this, and an arbitrary setting is possible. In the present embodiment, the shape of the opening of the recess 29 on the circumferential surface of the roller 28 is substantially circular, but is not limited to this. For example, it is substantially elliptical, substantially rectangular, almost rhomboid, substantially square, A substantially regular hexagon, a substantially regular octagon, or the like may be used.

[0069] The roller 28 can be manufactured, for example, by processing a recess-forming roller used for manufacturing the roller 4 by etching, sandblasting, electric discharge machining, laser machining, or the like. For the laser processing, the same method as that for forming the roller 4 is used.

When a recess is formed on the circumferential surface of the recess forming roller by laser processing, A bump (not shown) occurs at the opening edge 29a in the surface. By removing this bulge, a concave portion 29 having a curved opening edge 29a is formed, and a roller 28 is obtained. The removal of the bumps is preferably done by polishing with diamond particles. As the diamond particles, particles larger than the minimum size of the recess 29 are preferably used. More preferably, the average particle size of the diamond particles is 30 m or more and less than 35 m. Here, the size of the recess 29 means the opening diameter of the recess 29 on the circumferential surface of the roller 28. By using diamond particles having such an average particle diameter, the opening edge 29a is formed of a curved surface having a large radius of curvature, and peeling of the convex portion 22 from the base material portion 21 can be more significantly prevented. Further, the burying of the diamond particles inside the recess 29 is prevented.

The polishing using diamond particles can be performed in the same manner as a general polishing method, except that diamond particles are used as abrasive grains or polishing grains. Usually, it is carried out by a polishing machine having a polishing pad while placing diamond particles on the polishing surface and supplying a medium such as water.

The formation of the groove 29x on the surface of the opening edge 29a is preferably performed by polishing with diamond particles having an average particle size of 5 μm or less. Thereby, the groove 29x having a width of 1 μm or less and a depth of 1 μm or less can be easily formed. The formation of the groove 29x may be performed after the ridge is removed by polishing or simultaneously with the removal of the ridge by polishing. Since the diamond particles used here have a very small particle size, they can be easily removed by washing after the formation of the groove 29x that is difficult to be buried in the recess 29.

[0071] As with the roller 4, the surface facing the peripheral surface of the roller 28 and the inner space of the recess 29 obtained in this way, a coating layer containing cemented carbide, a coating layer containing alloy tool steel, One or more of a coating layer containing chromium oxide, a protective layer containing an amorphous carbon material, and a coating layer having a ceramic strength may be formed. As a result, the same effect as the formation of these coating layers and protective layers in the roller 4 can be obtained.

The roller 28 is arranged so that its peripheral surface is in pressure contact with the peripheral surface of the roller 5 and its axis is parallel to the axis of the roller 5, thereby forming a pressure-contacting two-pipe portion 34.

[0072] In the step shown in FIG. 8 (a), the current collector metal foil 10 is supplied to the press-fitting nipping portion 34, and pressures 30a and 30b in the thickness direction of the current collector metal foil 10 are applied. The In the process shown in FIG. 8 (b), of the surface of the current collector metal foil 10 facing the roller 28 circumferential surface, the contact surface in contact with the roller 28 circumferential surface is compressed by the applied pressures 30a and 30b. The non-contact surface that does not contact the roller 28 circumferential surface and faces the recess 29 is not subjected to compression processing. There is a contact surface around the non-contact surface. That is, by compressing the contact surface, the thickness of the contact surface becomes smaller than the thickness of the current collector metal foil 10, and the raised portion 21 x that becomes the prototype of the base material portion 21 is formed. On the other hand, the non-contact surface is applied with stress 31a and 31b from the periphery of the non-contact surface to the bottom of the recess 29 along the surface facing the inner space of the recess 29 as the contact surface is pressurized. Is done. As a result, plastic deformation of the non-contact surface begins to occur and rises toward the bottom of the concave portion 29 to form the convex portion 22x. At the same time, the boundary force between the raised portion 21x and the convex portion 22x is formed into a curved shape along the opening edge 29a of the concave portion 29. At this time, since the volume of the convex portion 22x is less than 50% of the volume of the internal space of the concave portion 29, the pressurization is further continued.

In the step shown in FIG. 8 (c), the current collector 20 is obtained. In the current collector 20, a boundary portion 22a between the base material portion 21 and the convex portion 22 is formed of a curved surface. The pressure applied by the rollers 28 and 5 is preferably such that the thickness t of the base material portion 21 is smaller than the thickness t of the current collector metal foil 10,

5 0

And until the maximum thickness t of the current collector 20 is greater than the thickness t of the current collector metal foil 10.

6 0

It is. The pressurization is more preferably performed until the volume of the convex portion 22 is 50% or more, preferably 50 to 85% of the volume of the internal space of the concave portion 29. If it is less than 50%, the height of the convex portion 29 becomes insufficient, and there is a possibility that the active material cannot be carried smoothly. Furthermore, there is a possibility that the active material may be peeled off from the current collector 20 after loading the active material. On the other hand, if it exceeds 85%, the air remaining inside the concave portion 29, the vapor of the lubricant, etc. are compressed and the internal pressure is increased, and the smooth plastic deformation of the convex portion 22 is hindered. Variations may occur.

[0074] In the current collector 20, the surface 21a on which the convex portion 22 of the base material portion 21 is not formed has a surface roughness different from that of the current collector metal foil 10, since it has been subjected to compression processing. Yes. The tip end surface of the convex portion 22 is not subjected to compression processing and is hardly affected by plastic deformation, and therefore has almost the same surface roughness as the current collector metal foil 10. Further, the side surface of the convex portion 22 is not compressed, but is affected by plastic deformation, so that the surface roughness close to the current collector metal foil 10 is obtained. have. Therefore, by supporting the active material layer on the surface of the convex portion 22, preferably on the tip surface, the active material layer is prevented from peeling off from the current collector 20 in the charge / discharge cycle.

FIG. 10 is a longitudinal sectional view schematically showing a configuration of a collector 23 for a non-aqueous electrolyte secondary battery in another form. FIG. 11 is a longitudinal sectional view schematically showing a method for manufacturing the current collector 23 shown in FIG. FIG. 11 (a) is a longitudinal sectional view showing a state immediately after the current collector metal foil 10 is supplied to the press-contact nip portion 34a. FIG. 11 (b) is a longitudinal sectional view showing a state in which the plastic deformation of the surface of the current collector metal foil 10 proceeds in the pressure contact ep portion 34a. FIG. 11 (c) is a longitudinal sectional view showing a state immediately after the current collector 23 is formed in the pressure-welding two-ply portion 34a.

The current collector 23 has the same configuration as the current collector 20 except that a plurality of convex portions 25x and 25y are formed on both surfaces in the thickness direction of the base material portion 24. . That is, the base material portion 24 has the same configuration as the base material portion 21. The convex portions 25x and 25y have the same configuration as the convex portion 22. The convex portion 25x is formed so as to extend or protrude from one surface in the thickness direction of the base material portion 24 toward the outside of the base material portion 24. The convex portion 25y is formed so as to extend or protrude from the other surface in the thickness direction of the base material portion 24 toward the outside of the base material portion 24. The direction in which the convex portion 25x extends is opposite to the direction in which the convex portion 25y extends.

[0077] Further, in the current collector 23, a boundary portion 25a between the base material portion 24 and the convex portions 25x, 25y is formed of a curved surface. As a result, the same effect can be obtained as when the boundary portion 22a of the current collector 20 is formed of a curved surface.

Further, in the cross section in the thickness direction of the current collector 23, the lines indicating the tip surfaces of the convex portions 25 x and 25 y are substantially parallel to the line indicating the surface 24 a of the base material portion 24. The tip surfaces of the convex portions 25x and 25y are substantially flat surfaces and have not been subjected to compression processing, and therefore have substantially the same surface roughness as the current collector metal foil 10 as a raw material. The side surfaces of the convex portions 25x and 25y are not compressed, but are affected by plastic deformation, and thus have a surface roughness close to that of the current collector metal foil 10. Therefore, by holding the active material layer on the surface of the convex portion 22, preferably on the tip surface, the active material layer is prevented from peeling off from the current collector 20 in the charge / discharge cycle. Further, in the current collector 23, the thickness of the base material portion 24 is formed to be smaller than the thickness t of the current collector metal foil 10 used as a raw material. Also, from the tip surface of convex part 25x, convex part 2

0

The thickness t to the tip surface of 7y is shaped to be larger than the thickness t of the current collector metal foil 10.

8 0

It is made. The thickness can also be defined as the maximum thickness of the current collector 23. This configuration

8

As a result, the mechanical strength of the current collector 23 is increased and the durability is increased.

[0079] The current collector 23 uses, for example, a current collector manufacturing apparatus that requires the same configuration except that the current collector manufacturing apparatus 35 shown in FIG. 5 uses two rollers 28 instead of the rollers 4 and 5. Can be produced.

FIG. 11 is a longitudinal sectional view for explaining a method of manufacturing the current collector 23 as described above.

Yes

In the step shown in FIG. 11 (a), the two rollers 28 are gathered on a pressure-welding dip portion 34a formed by arranging the circumferential surfaces so that their circumferential surfaces are in pressure-contact with each other and their axes are parallel to each other. Supply metal foil 10 for electrical equipment. The metal foil 10 for current collector is applied with pressures 30a and 30b in the thickness direction.

[0080] In the step shown in Fig. 11 (b), of the surfaces of the current collector metal foil 10 facing the roller 28 circumferential surface, the contact surface in contact with the roller 28 circumferential surface is compressed by the applied pressures 30a and 30b. Applied. On the other hand, the non-contact surface that does not contact the circumferential surface of the roller 28 and faces the recess 29 is not subjected to compression processing, but plastic deformation occurs with the compression processing of the contact surface. There is a contact surface around the non-contact surface. That is, when the contact surface is subjected to compression processing, the thickness at the contact surface becomes smaller than the thickness of the current collector metal foil 10, and the raised portion 24x that becomes the prototype of the base material portion 24 is formed. . On the other hand, as the non-contact surface is pressurized, the contact force from the periphery of the non-contact surface to the bottom of the recess 29 along the surface facing the inner space of the recess 29, the stress 31a, 31b, 31x and 31y are added. As a result, plastic deformation inside the non-contact surface progresses and rises toward the bottom of the recess 29, forming the protrusions 32x and 32y. At the same time, it is formed into a curved surface shape along the boundary force S between the raised portion 24x and the convex portions 32x and 32y and the opening edge 29a of the concave portion 29. At this time, since the volume of the convex portions 32x and 32y is less than 50% of the volume of the internal space of the concave portion 29, the pressurization is further continued.

In the step shown in FIG. 11 (c), the current collector 23 is obtained. In current collector 20, base material A boundary portion 25a between 24 and the convex portions 25x and 25y is formed of a curved surface. The pressure applied by the two rollers 28 is preferably such that the thickness t of the base material portion 24 is smaller than the thickness t of the current collector metal foil 10.

7 0 Until the maximum thickness t of the current collector 23 is greater than the thickness t of the current collector metal foil 10.

8 0

Done. The pressurization is more preferably performed until the volume force of the convex portions 25x and 25y reaches 50% or more, preferably 50 to 85% of the volume of the internal space of the concave portion 29. If it is less than 50%, the height of the convex part 29 becomes insufficient, and there is a possibility that the active material cannot be carried smoothly. Furthermore, there is a risk that the active material may be peeled off from the current collector 20 after the active material is loaded. On the other hand, if it exceeds 85%, the air remaining in the concave portion 29, the vapor of the lubricant, etc. are compressed and the internal pressure increases, and there is a possibility that the convex portions 25x and 25y may have a variation in shape.

In the present embodiment, when manufacturing current collectors 1, 15, 20, and 23 of the present invention, current collector manufacturing apparatus 35 shown in FIG. 5 or a current collector manufacturing apparatus similar thereto is used. Although it is used, it is not limited to this. For example, by using a die such as a die set die having a concave portion having a shape corresponding to the convex portion, the current collector metal foil 10 is sandwiched from both sides in the thickness direction by this die and pressed. Thus, the metal foil 10 for current collector can be subjected to the compression processing of the present invention. This also makes it possible to produce current collectors 1, 15, 20, and 23 of the present invention.

Further, the current collector obtained by the production method of the present invention is not limited to a force that can be suitably used as a current collector for a non-aqueous electrolyte secondary battery. For example, a current collector other than a non-aqueous electrolyte secondary battery can be used. It can also be used as a current collector for primary batteries such as secondary batteries and lithium primary batteries.

[0083] [Method for producing electrode for nonaqueous electrolyte secondary battery]

The method for producing an electrode for a non-aqueous electrolyte secondary battery of the present invention is the same as the conventional method for producing a current collector, except that the current collector produced by the production method of the present invention is used as the current collector. Can be implemented. For example, the active material layer can be supported on the surface of the current collector by applying an electrode mixture slurry to the surface of the current collector produced by the production method of the present invention and drying it. Further, a thin film active material layer may be formed on the current collector surface.

The convex portion of the current collector obtained by the production method of the present invention is formed without being subjected to compression processing. In addition, the convex surface is not affected by compression, and the tip surface of the convex part is particularly plastic. Since it is formed with almost no influence of deformation, there is no processing distortion. Therefore, when a thin film of an active material layer is formed on the surface of a current collector obtained by the production method of the present invention, a thin film having a uniform thickness can be formed with high accuracy. In addition, since the surface of the convex portion, particularly the tip surface of the convex portion, maintains the surface roughness of the metal foil before processing, the adhesion between the thin film as the active material layer and the current collector surface is improved. This effect is particularly remarkable when the active material layer is formed on a current collector in which the boundary portion between the base material portion and the convex portion is a curved surface.

[0085] The electrode mixture slurry includes a positive electrode mixture slurry and a negative electrode mixture slurry. First, the production of the positive electrode using the positive electrode mixture slurry will be described. The positive electrode mixture slurry contains a positive electrode active material and a solvent, and further contains a positive electrode binder, a conductive material, etc., as necessary. The positive electrode active material is used in the field of non-aqueous electrolyte secondary batteries. For example, lithium cobaltate and its modified products (such as lithium cobaltate in which aluminum or magnesium is dissolved), lithium nickelate and its modified products (part of nickel with cobalt) can be used. And substituted oxides such as lithium manganate and modified products thereof. One type of positive electrode active material can be used alone, or two or more types can be used in combination.

[0086] As the positive electrode binder, those commonly used in the field of non-aqueous electrolyte secondary batteries can be used. For example, polyvinylidene fluoride (PVdF), modified polyvinylidene fluoride, polytetrafluoroethylene (PTFE), attaly Examples thereof include a rubber particle binder having a rate unit. Together with such a positive electrode binder, an acrylate monomer or acrylate oligomer into which a reactive functional group has been introduced may be used. The positive electrode binder can be used alone or in combination of two or more.

[0087] As the conductive material, those commonly used in the field of non-aqueous electrolyte secondary batteries can be used, and examples thereof include carbon black such as amplifier black and thermal black, and various graphite. One type of conductive material can be used alone, or two or more types can be used in combination.

[0088] The positive electrode mixture slurry is prepared by, for example, dispersing a positive electrode active material and, if necessary, a binder for a positive electrode, a conductive material, and the like in an appropriate dispersion medium, and, if necessary, a viscosity suitable for applying a current collector. It is produced by adjusting to. As the dispersion medium, water, organic solvents such as 2-methyl-N-pyrrolidone, and the like can be used. For example, a general disperser such as a planetary mixer can be used to disperse the solid solvent such as the positive electrode active material.

The positive electrode mixture slurry is applied to one or both surfaces of the positive electrode current collector, dried, and subjected to press molding as necessary to adjust to a predetermined thickness, whereby a positive electrode plate is obtained. The thickness of the positive electrode current collector is not particularly limited, but is preferably 5 to 30 111. For application of the positive electrode mixture slurry to the positive electrode current collector, for example, a general application device such as a die coater can be used. The drying temperature is appropriately selected mainly depending on the type of solvent.

[0089] Next, the production of a negative electrode using a negative electrode mixture slurry will be described. The negative electrode mixture slurry contains a negative electrode active material and a dispersion medium, and further contains a negative electrode binder, a conductive material, and the like as necessary.

As the negative electrode active material, those commonly used in the field of non-aqueous electrolyte secondary batteries can be used.For example, various natural graphites, graphite materials such as artificial graphite, silicon-based composite materials such as silicide, various alloy materials, etc. Can be used. One type of negative electrode active material can be used alone, or two or more types can be used in combination.

[0090] As the binder for the negative electrode, those commonly used in the field of non-aqueous electrolyte secondary batteries can be used. For example, PVDF and modified products thereof, styrene butadiene copolymer rubber (SBR) particles and modified products thereof Examples of the body include cellulosic resins such as carboxymethylcellulose (CMC). The negative electrode binder can be used alone or in combination of two or more. In particular, a mixture of SBR particles and a cellulose resin, a mixture obtained by adding a small amount of a cellulose resin to SBR particles, and the like are preferable. When such a mixture is used, for example, lithium ion acceptability is improved.

As the conductive material, the same material as that used for the positive electrode can be used.

[0091] The negative electrode mixture slurry can be prepared in the same manner as the positive electrode mixture slurry. As the dispersion medium for dispersing the negative electrode active material, for example, water, an organic solvent such as 2-methyl-N pyrrolidone, or the like can be used.

The negative electrode mixture slurry is applied to one or both surfaces of the negative electrode current collector, dried, and subjected to press molding as necessary to adjust to a predetermined thickness, thereby obtaining a negative electrode plate. It is done. The thickness of the negative electrode current collector is not particularly limited, but is preferably 5 to 25 111. For the application of the negative electrode mixture slurry to the current collector, for example, a general application device such as a die coater can be used. The drying temperature is appropriately selected mainly depending on the type of solvent.

[0092] In order to form a thin film active material layer on the surface of the current collector, a vacuum process can be suitably used. Among them, a vapor deposition method, a sputtering method, a chemical vapor deposition method (CVD method), etc. Is preferred. For example, the active material is vapor-deposited on the surface of the current collector, for example, using a general vapor deposition apparatus. According to the vacuum deposition process, the active material layer can be selectively formed at a predetermined portion of the current collector. The vapor deposition apparatus is not particularly limited, but a vacuum vapor deposition apparatus that includes an electron beam heating means, heats the active material by the electron beam heating means to vaporize, and adheres the vapor to the collector surface is preferable. Such a vacuum deposition apparatus is commercially available from ULVAC, Inc., for example. In the case of vapor deposition, mainly only the active material is deposited.

[0093] In the case of performing vapor deposition, the active material is preferably a negative electrode active material. Examples of the negative electrode active material include Si, Sn, Ge, Al, alloys containing one or more of these, oxides such as SiOx and SnOx, and sulfides such as SiSx and SnS. The negative electrode active material layer is preferably formed in a columnar shape on the surface of the negative electrode current collector, preferably on the front surface of the convex portion of the negative electrode current collector. The negative electrode active material layer preferably contains an amorphous or low crystalline negative electrode active material.

[0094] The thickness of the active material layer formed on the current collector surface, preferably the convex surface, and more preferably the convex tip surface, is determined depending on the type of the active material, the method for forming the active material layer, and the final thickness obtained. The force that can be appropriately selected according to various conditions such as the characteristics required for the water electrolyte secondary battery and the use of the battery is preferably 5 to 30 111, more preferably 10 to 25 111.

[0095] [Nonaqueous electrolyte secondary battery]

The nonaqueous electrolyte secondary battery of the present invention includes the electrode of the present invention, its counter electrode, and a lithium ion conductive nonaqueous electrolyte. That is, the non-aqueous electrolyte secondary battery of the present invention is a non-aqueous electrolyte lithium secondary battery. When the nonaqueous electrolyte secondary battery of the present invention includes the electrode of the present invention as a negative electrode, the structure of the positive electrode is not particularly limited. In addition, when the nonaqueous electrolyte secondary battery of the present invention includes the electrode of the present invention as a positive electrode, the structure of the negative electrode is not particularly limited. The electrode of the present invention is preferably used as a negative electrode. FIG. 12 is a partially exploded perspective view schematically showing a configuration of a nonaqueous electrolyte secondary battery 40 that is one embodiment of the present invention. The nonaqueous electrolyte secondary battery 40 includes an electrode group 41, a positive electrode lead 42, a negative electrode lead (not shown), an insulating plate 44, a sealing plate 45, a gasket 46, and a battery case 47.

The electrode group 41 includes a positive electrode 50, a negative electrode 51, and a separator 52. The positive electrode 50, the separator 52, the negative electrode 51, and the separator 52 are overlapped in this order and wound to form a spiral shape. The electrode group 41 includes an electrolyte (not shown).

The positive electrode 50 includes a force that is an electrode of the present invention, or, when the negative electrode 51 is an electrode of the present invention, a positive electrode current collector and a positive electrode active material layer (not shown).

As the positive electrode current collector, those commonly used in this field can be used, and examples thereof include foils made of aluminum, aluminum alloys, stainless steel, titanium, and nonwoven fabrics. The thickness of the positive electrode current collector is not particularly limited, but is preferably 5 m to 30 m.

The positive electrode active material layer is formed on one surface or both surfaces in the thickness direction of the positive electrode current collector, contains the positive electrode active material, and includes a conductive material and a binder as necessary. Examples of the positive electrode active material include lithium such as lithium-containing transition metal oxides exemplified above and MnO.

2

No metal oxides can be used.

[0098] As the conductive material, those commonly used in this field can be used. For example, natural black lead, artificial graphite graphite, acetylene black, ketjen black, channel black, furnace black, lamp black, Carbon blacks such as thermal black, conductive fibers such as carbon fibers and metal fibers, metal powders such as carbon fluoride and aluminum, conductive whiskers such as zinc oxide and potassium titanate, and conductivity such as titanium oxide Examples include organic conductive materials such as metal oxides and phenylene derivatives.

Yes

[0099] Examples of the binder include polyvinylidene fluoride (PVDF), polytetrafluoroethylene, polyethylene, polypropylene, aramid, resin, polyamide, polyimide, polyamide, imide, polyacrylonitrile, Polyacrylic acid, polyacrylic acid methyl ester, polyacrylic acid ethyl ester, polyacrylic acid hexyl ester, polymethacrylic acid, polymethacrylic acid methyl ester, polymethacrylic acid ethyl ester, polymethacrylic acid hexyl ester, Examples thereof include poly (vinyl acetate), poly (pyrrolidone), polyether, polyether sulfone, hexafluoropolypropylene, styrene butadiene rubber, carboxymethyl cellulose, and rubber particle binders containing phthalate units. Tetrafluoroethylene, hexafluoroethylene, hexafnoreopropylene, naphtholeoloanorequinole vininoreethenole, vinylidene fluoride, chlorotrifnoreo ethylene, ethylene, propylene, pentafluoropropylene, fluorene A copolymer composed of two or more monomer compounds selected from chloromethyl ether, acrylic acid, hexagen, an acrylate monomer containing a reactive functional group, an acrylate oligomer containing a reactive functional group, and the like is bonded. It may be used as a dressing.

[0100] The positive electrode 50 is manufactured, for example, as follows. First, a positive electrode mixture slurry is prepared by mixing and dispersing a positive electrode active material and, if necessary, a conductive material and a binder in a dispersion medium. As the dispersion medium, for example, a dispersion medium commonly used in this field such as N-methyl 2-pyrrolidone can be used. For example, a general disperser such as a planetary mixer can be used to mix and disperse the dispersion medium such as the positive electrode active material. The positive electrode mixture slurry thus obtained is applied to one or both surfaces of the positive electrode current collector, dried, and rolled to a predetermined thickness, whereby a positive electrode active material layer is formed and the positive electrode 50 is obtained.

[0101] The negative electrode 51 includes a force that is an electrode of the present invention, or a negative electrode current collector and a negative electrode active material layer (not shown) when the positive electrode 50 is an electrode of the present invention.

As the negative electrode current collector, those commonly used in this field can be used, and examples thereof include metal foil and metal film made of copper, nickel oleore, iron, an alloy containing at least one of these, and the like. Of these, metal foils and metal films made of copper or copper alloys are preferred. As the copper alloy, a copper alloy can be used as exemplified earlier in this specification. Taking copper and copper alloy metal foils as examples, for example, electrolytic copper foil, electrolytic copper alloy foil, rolled copper foil, copper alloy foil, rolled copper alloy foil, and foils that have been subjected to surface roughening treatment. Can be mentioned. As the foil subjected to the roughening treatment, electrolytic copper foil, rolled copper foil, copper alloy foil and the like are preferable.

[0102] The thickness of the negative electrode current collector is not particularly limited, but is preferably 5 m to 100 m, and more preferably 8 to 35 m. If the thickness of the negative electrode current collector is less than 5 m, the mechanical strength of the negative electrode current collector may be insufficient, and the handleability during electrode production will be reduced. In addition, the electrode is easily broken when the battery is charged. On the other hand, if the thickness of the negative electrode current collector exceeds lOO ^ m, the mechanical strength is ensured. The volume of the negative electrode current collector occupies the entire electrode, and the battery capacity cannot be sufficiently increased. There is.

[0103] The negative electrode active material layer is formed on one surface or both surfaces in the thickness direction of the negative electrode current collector, contains the negative electrode active material, and includes a conductive material, a binder, a thickener, and the like as necessary. including. As the negative electrode active material, for example, graphite materials such as various natural graphites and artificial graphite, silicon-based composite materials such as silicide, alloy-based negative electrode active materials, and the like can be used. As the conductive material, the same material as that added to the positive electrode active material layer can be used. As the binder, the same material as that added to the positive electrode active material layer can be used. Furthermore, from the viewpoint of improving lithium ion acceptability, styrene-butadiene copolymer rubber particles (SBR) and modified products thereof can be used as a binder.

[0104] As the thickener, those commonly used in this field can be used. Among them, those having water solubility and viscosity in the form of an aqueous solution are preferred. For example, cellulose resins such as carboxymethyl cellulose (CMC) and modified products thereof, polyethylene oxide (PEO), polybulu alcohol (PVA). Among these, a cellulose resin and a modified product thereof are particularly preferable from the viewpoints of dispersibility of the negative electrode mixture slurry and viscosity increase described later.

The negative electrode 51 can be produced in the same manner as the positive electrode 50 except that a negative electrode active material and, if necessary, a conductive material, a binder, a thickener, etc. are mixed and dispersed in a dispersion medium to prepare a negative electrode mixture slurry. .

[0105] As the separator 52, those commonly used in the field of non-aqueous electrolyte secondary batteries can be used. For example, a microporous film of polyolefin such as polyethylene or polypropylene is generally used singly or in combination. And also preferred as an aspect! More specifically, the separator 52 includes a porous film made of a synthetic resin. Examples of the synthetic resin include polyolefins such as polyethylene and polypropylene, aramid resins, polyamideimides, polyphenylene sulfide, polyimides, and the like. Examples of the porous membrane include a microporous membrane and a nonwoven fabric.

[0106] In addition, the separator 52 has an anolemina, magnesia, silica, tita or the like inside or on the surface. You may include heat resistant fillers, such as your. Further, a heat-resistant layer may be provided on both sides or one side of the separator 52 in the thickness direction. The heat-resistant layer includes, for example, the heat-resistant filler and a binder. The same binder as that used for the positive electrode active material layer can be used. The thickness of the separator 17 is not particularly limited, but is preferably 10 m to 30 m, more preferably 10 to 25 μm.

[0107] As the nonaqueous electrolyte, an electrolyte solution in which a solute is dissolved in an organic solvent, a polymer electrolyte containing a solute and an organic solvent, and non-fluidized with a polymer compound, a solid electrolyte, or the like can be used. When using an electrolyte solution, the separator 17 is preferably impregnated with the electrolyte solution. The non-aqueous electrolyte may contain additives in addition to the solute, the organic solvent, and the polymer compound.

[0108] The solute is selected based on the oxidation-reduction potential of the active material. Specifically, as solutes, solutes commonly used in the field of lithium batteries can be used, for example, LiPF, LiBF,

6 4

LiCIO, LiAlCl, LiSbF, LiSCN, LiCF SO, LiN (CF CO), LiN (CF SO)

4 4 6 3 3 3 2 3 2

, LiAsF, LiB CI, lower aliphatic lithium carboxylate, LiF, LiCl, LiBr, Lil, black

2 6 10 10

Roborane lithium, bis (1,2-benzenediolate (2—) 10,0,) lithium borate, bis (2,3 naphthalenediolate (2) 1 O, ○,) lithium borate , Borate salts such as bis (2,2, bibididiolate (2—) -0, 〇,) lithium borate, bis (5 fluoro-2-olate-1 benzenesulfonic acid—O, Ο ′) lithium borate, ( CF SO) NLi

3 2 2

, LiN (CF SO) (C F SO), (C F SO) NLi, lithium tetraphenylborate, etc.

3 2 4 9 2 2 5 2 2

Is mentioned. Solutes can be used alone or in combination of two or more as required

[0109] As the organic solvent, organic solvents commonly used in the field of lithium batteries can be used. For example, ethylene carbonate (EC), propylene carbonate, butylene carbonate, vinylene carbonate, dimethylolene carbonate (DMC), Tinole carbonate, Ethenole methyl carbonate (EMC), Dipropyl carbonate, Methyl formate, Methyl acetate, Methyl propionate, Ethyl propionate, Dimethoxymethane, γ-Butyrolatatane, _ΊVale latataton, 1, 2-diethoxyethane, 1, 2 —Tetrahydrofurans such as dimethoxyethane, ethoxymethoxyethane, trimethoxymethane, tetrahydrofuran and 2-methyltetrahydrofuran Derivatives, dimethyl sulfoxide, dioxolane derivatives such as 1,3-dioxolane, 4-methyl-1,3-dioxolane, formamide, acetoamide, dimethylformamide, acetonol, Unore, propinoreconi! ; Nole, methane methane, ethinolemonoglyme, phosphoric acid !; Estenole, oxalate, propionate, sulfolane, 3-methylsulfolane, 1,3-dimethylthiolane, imidazolidinone, 3— Examples include methyl-2-oxazolidinone, propylene carbonate derivatives, ethyl ether, jetyl ether, 1,3-propane sultone, aniso-norole, and fluorobenzene. One organic solvent can be used alone, or two or more organic solvents can be used in combination as required.

[0110] Examples of the additive include vinylene carbonate, cyclohexylbenzene, biphenylenole, diphenenoleatenore, vinylenoleethylene carbonate, divininoleethylene carbonate, phenylethylene carbonate, diaryl carbonate. , Fluoroethylene carbonate, catechol carbonate, butyl acetate, ethylene sulfite, propane sulfate, trifluoropropylene carbonate, dibenzofuran, 2,4 difluoroadiazole, o terphenyl, m terphenyl, etc. May be included. One additive can be used alone, or two or more additives can be used in combination as required.

[0111] The non-aqueous electrolyte is a polymer material such as polyethylene oxide, polypropylene oxide, polyphosphazene, polyaziridine, polyethylene sulfide, polybutyl alcohol, polyvinylidene fluoride, and polyhexafluoropropylene. The above solute may be mixed with a seed or a mixture of two or more kinds and used as a solid electrolyte. Moreover, you may mix with the said organic solvent and use it in a gel form. In addition, lithium nitride, lithium halide, lithium oxyacid salt, Li SiO Li L

4 4, SiO Lil LiOH

4 4, Li PO Li SiO

3 4 4 4, Li SiS

2 3, i PO Li S—SiS, phosphorus sulfide compounds and other inorganic materials can be used as solid electrolytes

3 4 2 2

Good. When a solid electrolyte or a gel electrolyte is used, the separator 17 may be disposed between the positive electrode 50 and the negative electrode 51. Alternatively, the gel electrolyte may be disposed adjacent to the separator 52.

[0112] Positive electrode lead 42, negative electrode lead, insulating plate 44, sealing plate 45, gasket 46, and battery case

As for 47, any of those commonly used in the field of non-aqueous electrolyte secondary batteries can be used. A positive terminal 53 is provided at the center of the sealing plate 45. The nonaqueous electrolyte secondary battery 40 of the present invention is manufactured, for example, as follows. One end of each of the positive electrode lead 42 and the negative electrode lead is electrically connected to the positive electrode current collector of the positive electrode 50 and the negative electrode current collector of the negative electrode 51, respectively. The electrode group 41 is housed inside the bottomed cylindrical battery case 47 together with the insulating plate 44. Connect the other end of the negative electrode lead led out from the bottom of the electrode group 41 to the bottom of the battery case 47, then connect the positive electrode lead 42 led out from the top of the electrode group 41 to the sealing plate 45 and place it in the battery case 47. A nonaqueous electrolyte (not shown) is injected. Next, a sealing plate 45 with a gasket 46 attached to the periphery is inserted into the opening of the battery case 47, and the opening of the battery case 47 is folded inward and crimped to seal the nonaqueous electrolyte secondary battery. 40 is obtained.

[0113] Fig. 13 is a cross-sectional view schematically showing a configuration of a stacked battery 55 which is one embodiment of the present invention. The laminated battery 55 includes a positive electrode 56, a negative electrode 57, a separator 58, a battery case 59, a positive electrode lead 60, a negative electrode y-node 61, and a sealing resin 62. The positive electrode 56 includes a positive electrode current collector 56a and a positive electrode active material layer 56b formed on one surface in the thickness direction of the positive electrode current collector 56a. The negative electrode 57 includes a negative electrode current collector 57a and a negative electrode active material layer 57b formed on one surface in the thickness direction of the negative electrode current collector 57a. The positive electrode 56 and the negative electrode 57 are provided to face each other with the separator 58 interposed therebetween. That is, in the laminated battery 55, the positive electrode 56, the separator 58, and the negative electrode 57 are stacked in this order and stacked to form a flat electrode group. The positive electrode 56, the negative electrode 57, and the separator 58 have the same configurations as the positive electrode 50, the negative electrode 51, and the separator 52 in the nonaqueous electrolyte secondary battery 40, respectively.

[0114] The battery case 59 is a container-like member having two openings, and accommodates an electrode group in its internal space. The two openings of the battery case 59 are each sealed with a sealing resin 62. One end of the positive electrode lead 60 is electrically connected to the positive electrode current collector 66 a and the other end of the positive electrode lead 60 is led out of the battery 55 by one opening force of the battery case 59. One end of the negative electrode lead 61 is electrically connected to the negative electrode current collector 57 a, and the other open end of the battery case 59 is also led out of the battery 55. Also, in the laminated battery 55, the same non-aqueous electrolyte as in the non-aqueous electrolyte secondary battery 40 can be used.

As described above, the nonaqueous electrolyte secondary battery of the present invention includes, for example, a prismatic battery having a spirally wound electrode group, a cylindrical battery having a spirally wound electrode group, and a stacked electrode group. Various forms, such as a stacked battery having the above, can be adopted.

According to the method for manufacturing a current collector and an electrode plate for a non-aqueous secondary battery according to the present invention, the strength of the current collector for producing the electrode plate is ensured, and the convex portions formed on the current collector Since an electrode active material can be efficiently carried on the substrate and a highly reliable non-aqueous secondary battery can be obtained, a higher capacity is desired as electronic devices and communication devices become more multifunctional. It is useful as a power source for portable electronic devices. Example

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.

(Example 1)

[0116] (Preparation of current collector for negative electrode)

Using the current collector manufacturing apparatus 35 shown in FIG. 3, the negative electrode current collector 1 of the present invention was produced as follows. The roller 4 is a cemented carbide roller having a diameter of 50 mm, and concave portions 4a are formed on the peripheral surface thereof with the arrangement pattern shown in FIG. The opening diameter of the recess 4a was 10 m, and the depth was 8 ^ 111. When the recess 4a was formed by laser processing, a raised portion appeared at the edge of the opening of the recess 4a, but this was removed by polishing. Roller 5 was a 50 mm diameter iron roller with a flat peripheral surface. The pressure of contact between the roller 4 and the roller 5 at the pressure dip portion 6 was 10 kN in terms of linear pressure.

[0117] A copper foil for a current collector having a thickness of force S 18 πι was wound around a metal foil supply roller 36 and shown in FIG.

0

It was attached to the current collector manufacturing apparatus 35. This copper foil for current collector is supplied to the pressure-welded ep portion 6 of the processing means 7, and the copper foil is subjected to partial non-compression processing, as shown in FIG. A current collector 1 was produced and wound around a winding roller 38. t ttl Z ^ m, t is 21 m

1 2

I got it. That is, t> t> t.

2 0 1

In the current collector 1, the surface of the circumferential surface of the roller 4 facing the recess 4 a was plastically deformed along with the compression processing of other portions, and the protrusion 3 was formed. On the other hand, the convex surface was not formed on the surface facing the roller 5 having a flat peripheral surface, and the surface was a flat surface.

A cross section in the thickness direction of the current collector 1 obtained here was observed with a scanning electron microscope. FIG. 18 is an electron micrograph of a cross section of the current collector 1. From Fig. 18, current collector 1 It is clear that problems such as warping and wrinkles occur!

[0118] (Production of negative electrode)

The current collector 1 obtained above was mounted inside a vacuum deposition apparatus equipped with an electron beam heating means. Using silicon with a purity of 99.9999% as a target and performing deposition while introducing oxygen with a purity of 99.7%, a SiO layer with a thickness of 20 m was formed on the surface of the convex part 3 of the current collector 1.

0.5. This was slit to a predetermined width to prepare a negative electrode plate.

[0119] (Example 2)

A negative electrode current collector 1 was produced in the same manner as in Example 1, except that the raised portion generated when the concave portion 4a was formed on the peripheral surface of the roller 4 was used without being removed by polishing. t was 17 m and t was 21 nm. That is, t> t> t. Obtained negative electrode collection

1 2 2 0 1

When the cross section of the electric body 1 was observed with a microscope in the same manner as in Example 1, no occurrence of defects such as waving, warping, and wrinkles was observed. An SiO layer having a thickness of 20 μm was formed on the surface of the convex portion 3 of the current collector for negative electrode 1 in the same manner as in Example 1. Slitter this to a predetermined width

0.5

The negative electrode plate was produced by processing.

[0120] In the negative electrode current collector 1 obtained in Examples 1 and 2, the convex portion 3 was formed by subjecting one surface of the copper foil to the compression processing of the present invention. Such a negative electrode current collector 1 was able to efficiently deposit a negative electrode active material on the surface of the protrusion 3. In addition, it had sufficient durability against the tensile stress applied in the longitudinal direction of the negative electrode current collector 1. Therefore, when the negative electrode active material is vapor-deposited on the negative electrode current collector 1, or when slitting to a predetermined width after the negative electrode active material is vapor-deposited, local deformation and stagnation are applied to the negative electrode current collector 1. Is prevented from occurring. At the same time, the negative electrode active material layer could be prevented from falling off.

[0121] (Example 3)

In the current collector manufacturing apparatus 35, except that the roller 5 is changed to the roller 4, as in Example 1, the convex portions 17x and 17y are formed on both surfaces in the thickness direction of the base material portion 16 as shown in FIG. A negative electrode current collector 15 shown in c) was produced. t was 16 ^ 111 and t was 25 m. That is, t> t

3 4 4

> t. The cross section of the obtained negative electrode current collector 15 was observed with a microscope in the same manner as in Example 1.

0 3

As a result, the occurrence of defects such as waviness, warpage and wrinkles was not recognized. On the surface of the convex portions 17x and 17y of the negative electrode current collector 15, a SiO layer with a film thickness of 20 111 was formed in the same manner as in Example 1. Formed. This was slit to a predetermined width to prepare a negative electrode plate.

[0122] (Example 4)

In the current collector manufacturing apparatus 35, except that the roller 5 is changed to the roller 4, as in Example 2, the convex portions 17x and 17y are formed on both surfaces in the thickness direction of the base material portion 16 as shown in FIG. A negative electrode current collector 15 shown in c) was produced. t was 16 ^ 111 and t was 25 m. That is, t> t

3 4 4

0 3

As a result, the occurrence of defects such as waviness, warpage and wrinkles was not recognized. On the surface of the convex portions 17x and 17y of the negative electrode current collector 15, a SiO layer with a film thickness of 20 111 was formed in the same manner as in Example 1.

0.5 formed. This was slit to a predetermined width to prepare a negative electrode plate.

[0123] The negative electrode current collector 15 obtained in Examples 3 and 4 was subjected to the compression processing of the present invention on both sides of the copper foil, whereby partial plastic deformation occurred, and the convex portions 17x and 17y were formed. It was. Such a negative electrode current collector 15 was able to efficiently deposit a negative electrode active material on the surfaces of the convex portions 17x and 17y. Moreover, the anode current collector 1 had sufficient durability against the tensile stress applied in the longitudinal direction. For this reason, when depositing a negative electrode active material on the negative electrode current collector 1, or when slitting it to a predetermined width after the deposition of the negative electrode active material, local deformation and stagnation of the negative electrode current collector 1 occur. Is prevented from occurring. At the same time, it was possible to suppress the negative electrode active material layer from falling off with the force S.

[0124] (Comparative Example 1)

The surface shape shown in Fig. 20 (a) was applied to the peripheral surface of a 50 mm diameter cemented carbide roller with a flat peripheral surface. Except that this roller was used in place of the roller 4 in the current collector production apparatus 35, the current collector copper foil (thickness 18πι) was processed in the same manner as in Example 1. The cut surface of the processed copper foil was observed with a scanning electron microscope. FIG. 19 is an electron micrograph of the cross section of the current collector 90 obtained in Comparative Example 1. From FIG. 19, it is clear that the current collector of Comparative Example 1 is struck. Further, in the current collector manufacturing apparatus 35, the roller 5 was used in place of the rubber roller and the copper foil for the current collector was processed, but the undulation could not be eliminated.

[0125] From the above results, the current collector obtained by the production method of the present invention has a plurality of convex portions formed on its surface due to partial plastic deformation accompanying compression processing, and the convex portions have sufficient durability. Sex It is clear that it will work. Therefore, local deformation and sag of the current collector are prevented in the step of forming the convex portion on the surface of the metal foil and the step of supporting the electrode active material on the convex portion of the current collector. Also, the electrode active material can be prevented from falling off even in the step of supporting the electrode active material on the convex portion of the current collector and the step of slitting to a predetermined width.

[0126] Further, in the electrode obtained by the manufacturing method of the present invention, the surface of the tip of the convex portion of the current collector is hardly affected by compression processing and plastic deformation, so that no processing strain remains on the surface of the convex portion. The surface accuracy is good. Therefore, a uniform thin film can be formed. In addition, since the tip surface of the convex part maintains the initial surface roughness that does not decrease the surface roughness due to the compression processing, the adhesion with the thin-film active material layer can be increased. It can be considered. From this point of view, it is very effective to make the surface of the current collector before processing more rough in order to further increase the adhesion between the convex surface and the active material. It is done.

[Example 5]

Ceramic rollers having a substantially circular opening shape and a plurality of recesses 4a each having a depth of 10111 and an opening diameter of 10 m were mounted as rollers 4 and 5 in the current collector manufacturing apparatus 35 shown in FIG. The strip-shaped aluminum foil of thickness δ δ ΐ η, which is the metal foil 10 for the current collector, is passed through the pressure welding two-ply part 6 of the current collector manufacturing device 35 under a pressure of 10 kN and partially uncompressed. Processing was performed to produce a positive electrode current collector 70 shown in FIG. FIG. 14 is a drawing schematically showing a configuration of a current collector 70 which is one embodiment of the present invention. 14 (a) is a perspective view of the current collector 70. FIG. FIG. 14B is a longitudinal sectional view of the current collector 70, that is, a sectional view in the thickness direction.

[0128] The obtained current collector 70 is composed of a base portion 71 made of aluminum, and a substantially circular convex portion 72x, 72y having a height of 4 m and regularly formed on both surfaces of the base portion 71 in the thickness direction. (Hereinafter referred to as “convex portion 72”), and the base portion 71 has a thickness t force 2 111 and a maximum thickness t force ^ O ^ m.

3 4

Current collector. In the width direction (longitudinal direction) X, row units 73 in which convex portions 72 are arranged in a line at a pitch P are formed. In the lateral direction Y, the row units 73 are arranged in parallel by the pitch P. Furthermore, in line unit 73 and adjacent line unit 73,

2

The convex portions 72 are arranged so as to be shifted by 0.5 P in the width direction X. Such an array pattern of the protrusions 72 is a close-packed array. [0129] Next, an aluminum foil having a length of 1000 mm and a thickness of 15 m was used, and the volume ratio of the convex portion 72 was changed as shown in Table 1 by adjusting the pressing force at the pressure-welding nip portion 6. Except for the above, a convex portion 72 having a volume ratio different from the internal space volume of the concave portion 4a was formed in the same manner as described above, a current collector 70 was produced, and its surface condition was evaluated. The evaluation was performed by visually examining the number of wrinkles, warpage, and breakage of 1000 current collectors 70 to determine the occurrence rate. The results are shown in Table 1.

In Table 1, the volume ratio of the convex portion is a percentage of the volume of the convex portion 72 with respect to the internal space volume of the concave portion 4a. The same shall apply hereinafter.

[0130] [Table 1]

[0131] When the current collector 70 is manufactured, a tensile stress is applied in the longitudinal direction X of the current collector 70. If the current collector 70 is not durable against tensile stress, the current collector 70 will have problems such as wrinkling, warping, and cutting. However, as is apparent from Table 1, when the volume ratio of the protrusions 72 is 85% or less, the almost circular protrusions 72 are formed in a close-packed arrangement. The current collector 70 had sufficient durability against the tensile stress applied in the longitudinal direction X, and the occurrence of the above-described defects could be suppressed. In the present embodiment, only the embodiment in which the volume ratio of the convex portion 72 is up to 55% is described, but when the volume ratio is 55% or less, the pressing force is further reduced, so that It was possible to manufacture the current collector 70 without causing defects. On the other hand, when the volume ratio of the convex portion 72 was larger than 85%, the strength of the surface 71a of the base material portion 71 was insufficient, and defects such as wrinkles, warpage, and cutting occurred locally.

[0132] Further, when the surface roughness of the positive electrode current collector 70 having a volume ratio of the convex portion 72 of 85% or less was measured with a surface roughness meter, the surface roughness of the surface 71a of the base material portion 71 was It was smaller than the surface roughness of the aluminum foil before processing. The surface roughness of the surface 71a of the base material portion 71 was almost equal to the surface roughness of the ceramic peripheral surface.

On the other hand, the surface roughness of the tip surface of the protrusion 72 was almost equal to the surface roughness of the aluminum foil before processing. Further, when the tip surface of the convex portion 72 was observed with a scanning electron microscope, the same fine scratches as those observed on the surface of the aluminum foil before processing were observed.

[0133] Further, when the crystal orientation analysis of the current collector 70 by the backscattered electron diffraction image (EBSP) method was performed, the surface 71a of the base material 71 and the inside of the convex part 72 were an aluminum foil before processing. It was observed that the crystal grains were more vigorous than. Further, when the tensile strength of the current collector 70 was measured, no decrease in tensile strength was observed even though the thickness of the base material portion 71 was thinner than the thickness of the aluminum foil before processing. Since the base material portion 71 is subjected to compression processing, it is presumed that the tensile strength has been improved by work hardening by compression processing.

From the above analysis results, by applying the above processing to the aluminum foil, the convex portion 72 is not compressed, and the surface 71a of the base material portion 71 is compressed, and the current collector It is thought that 70 was obtained.

[Example 6]

The current collector shown in Fig. 3 is manufactured from a ceramic roller with multiple openings 4a with a rhombus shape and a depth of 10 111 and an opening diameter of 20 m (long diagonal length of the rhombus). Mounted as rollers 4 and 5 in apparatus 35. The metal foil 10 for the current collector is passed through a 12 m thick strip-shaped copper foil through the pressure welding two-ply part 6 of the current collector production device 35 under a linear pressure of 10 kN for partial non-compression processing. As a result, a positive electrode current collector 75 shown in FIG. 15 was produced. FIG. 15 is a drawing schematically showing a configuration of a current collector 75 which is one of the embodiments of the present invention. FIG. 15A is a perspective view of the current collector 75. FIG. 15B is a longitudinal sectional view of the current collector 75. [0135] The obtained current collector 75 includes a base material portion 76 made of copper, and a substantially rhomboid convex portion 77x having a height of 4 m, which is regularly formed on both surfaces of the base material portion 76 in the thickness direction. 77y (hereinafter referred to as “convex portion 77”), and a base-like portion 71 having a thickness t force 0 111 and a maximum thickness t force S i 8 m

3 4

It was a body. In the width direction (longitudinal direction) X, the convex portions 77 are arranged in a line at a pitch P.

Three

A row unit 78 is formed. In short direction Y, line unit 78 is flat at pitch P.

Arranged in 4 rows. Furthermore, in the row unit 78 and the row unit 78 adjacent thereto, the convex portions 77 are arranged so as to be shifted by 0.5 · 5P in the width direction X. Such protrusions 77

Three

This arrangement pattern is a close-packed arrangement.

[0136] Next, a copper foil having a length of 1000 mm and a thickness of 12 m was used, and the volume ratio of the convex portion 77 was changed as shown in Table 2 by adjusting the pressing force at the pressure-welding nipping portion 6. In the same manner as described above, a convex portion 77 having a volume ratio different from the internal space volume of the concave portion 4a was formed, a current collector 75 was produced, and its surface state was evaluated. The evaluation was performed by visually checking the number of wrinkles, warpage, and breakage of 1000 current collectors 75, and obtaining the respective occurrence rates. The results are shown in Table 2.

In Table 2, the volume ratio of the convex portion is a percentage of the volume of the convex portion 77 with respect to the internal space volume of the concave portion 4a. The same shall apply hereinafter.

[0137] [Table 2]

Wrinkle defect on convex part Warp defect Cut defect

Volume ratio Occurrence rate Occurrence rate Occurrence rate

(%) (%) (%) (%)

5 5 0 0 0

6 5 0 0 0

7 5 0 0 0

8 1 0 0 0

8 3 0 0 0

8 5 0 0 0

8 7 1 .4 3 0 .4

8 9 5 9 1. 7 When producing the current collector 75, a tensile stress is applied in the longitudinal direction X of the current collector 75. If the current collector 75 is not durable against tensile stress, the current collector 75 will have problems such as wrinkles, warpage, and breakage. However, as is apparent from Table 1, when the volume ratio of the convex portions 77 is 85% or less, the fact that the substantially circular convex portions 77 are formed in a close-packed arrangement is combined. The electric conductor 75 has sufficient durability against the tensile stress applied in the longitudinal direction X, and the occurrence of the above-described defects can be suppressed. In the present example, only the example in which the volume ratio of the convex portion 77 is up to 55% is described, but when the volume ratio is 55% or less, the pressing force is further reduced, so that On the other hand, if the volume ratio of the convex portion 77 is greater than 85%, the strength of the surface 76a of the base material portion 76 is insufficient, and wrinkles, warpage, and cutting are possible. Such defects occurred locally.

[0139] Further, when the surface roughness of the positive electrode current collector 75 in which the volume ratio of the convex portions 77 is 85% or less was measured with a surface roughness meter, the surface roughness of the surface 76a of the base material portion 76 was It was smaller than the surface roughness of the aluminum foil before processing. The surface roughness of the surface 76a of the base material portion 76 was almost equal to the surface roughness of the ceramic peripheral surface.

On the other hand, the surface roughness of the tip surface of the protrusion 77 was almost equal to the surface roughness of the aluminum foil before processing. Further, when the tip surface of the convex portion 77 was observed with a scanning electron microscope, the same fine scratches as those observed on the surface of the aluminum foil before processing were observed.

[0140] Further, when the crystal orientation analysis of the current collector 75 by the backscattered electron diffraction image (EBSP) method was performed, the surface 76a of the base material portion 76 and the inside of the convex portion 77 are aluminum foil before processing. It was observed that the crystal grains were more vigorous than. Further, when the tensile strength of the current collector 75 was measured, no decrease in tensile strength was observed even though the thickness of the base material portion 76 was thinner than the thickness of the aluminum foil before processing. Since the base material portion 76 is subjected to compression processing, it is presumed that the tensile strength has been improved by work hardening by compression processing.

From the above analysis results, by applying the above processing to the aluminum foil, the convex portion 77 is not compressed, and the surface 76a of the base material portion 76 is compressed, and the current collector It is considered that 75 was obtained. [0141] (Example 7)

Example except that 18 m thick copper foil was used instead of 12 m thick copper foil, and the pressing force at the pressure welding two-ply part 6 was adjusted so that the volume ratio of the convex part 77 would be 80%. In the same manner as in Example 6, a strip-shaped current collector 75 was produced. The current collector 75 had sufficient durability against the tensile stress applied in the longitudinal direction X because the substantially rhombic projections 77 were arranged in a close-packed shape. For this reason, when the current collector 75 is processed, it is possible to prevent local deformation and stagnation of the current collector 75 and to prevent the active material from peeling off from the current collector 75. The The processing of the current collector 75 includes supporting an active material on the surface of the current collector 75, slitting an electrode obtained by supporting the active material on the surface of the current collector 75, and the like.

[0142] The current collector 75 obtained above was mounted inside a vacuum vapor deposition apparatus equipped with an electron beam heating means. Using silicon with a purity of 99.9999% as a target, vapor deposition was performed while introducing oxygen with a purity of 99.7%, and a columnar SiO film with a thickness of 25 m was formed on the surface of the convex part 77 of the current collector 75.

0. Layer formed. This slitter is applied to a predetermined width in a cylindrical nonaqueous electrolyte secondary battery.

Five

The negative electrode plate was produced by processing. In the current collector 75, the substantially rhombic protrusions 77 are arranged in a close-packed shape, so that when the negative electrode active material is deposited in the short direction Y, it adheres efficiently to the surface of the protrusions 77. I was able to.

[0143] According to the production methods of Examples 5 to 7 of the present invention, partial plastic deformation is applied to the surface of the current collector metal foil by using the ceramic roller having a plurality of recesses formed on the peripheral surface. To form a convex part. In addition, by making the volume of the convex part less than or equal to the internal space volume of the concave part, variations in the shape and size of the convex part are eliminated. As a result, the mechanical strength and thus durability of the current collector obtained can be improved. Furthermore, the durability of the current collector is further improved by selecting the arrangement pattern of the convex portions. Therefore, in the process of producing a current collector by forming convex portions on the surface of the current collector metal foil, the process of producing an electrode by supporting an active material on the surface of the current collector, It is possible to remarkably prevent the occurrence of local defects. In addition, it is possible to prevent the active material from being separated from the current collector in the step of manufacturing the electrode by supporting the active material on the current collector surface, the step of slitting the electrode to a predetermined width, and the like.

[0144] Further, according to the manufacturing method of the present invention, the convex portions of the current collector are subjected to plastic deformation accompanying compression processing. Since the tip surface of the convex portion is hardly affected by plastic deformation, almost no processing distortion occurs on the tip surface of the convex portion. Therefore, the surface accuracy of the tip surface of the convex portion is good, and a uniform thin-film active material layer can be formed on the tip surface. Further, since the tip surface of the convex portion has not been subjected to compression processing, the surface roughness of the metal foil for the current collector is maintained without reducing the surface roughness force S. Therefore, it is considered that the adhesion with the active material layer is further increased. From this point of view, in order to further enhance the adhesion between the flat surface of the convex portion and the electrode active material, it is very effective to previously roughen the surface of the current collector before processing. Conceivable.

[Example 8]

A roller 28 shown in FIG. 9 was produced as follows. Chamfering hole made of cemented carbide with a diameter of 50 mm A circular recess with an opening of about 10 m in diameter and a depth of about 8 m is formed on the peripheral surface of one la by laser processing using a YAG laser. did. The laser frequency of laser processing is ΙΚΗζ.

At the edge of the opening of the recess formed as described above, a bulge consisting of a groove and a bulge was formed, and the surface roughness of the roller partially increased. For this reason, diamond particles having an average particle diameter of 8 m were used as abrasive grains, and polishing was performed with a polishing machine equipped with a polishing pad while supplying water. Polishing was performed until the average surface roughness of the roller peripheral surface reached 0.4a. As a result, the ridges were removed, and the recesses 29 having the curved edges 29a were formed, and the rollers 28 were produced.

[0146] The surface roughness of the roller 28 is approximately the same as the surface roughness of the metal foil as the raw material. Therefore, in the current collector obtained after compression processing, the tip end surface of the convex portion maintains the surface roughness of the original metal foil, and the surface of the base material portion is subjected to compression processing by the roller 28, and the roller 28 The surface roughness is almost the same as the surface roughness. That is, the entire surface of the current collector has almost the same surface roughness. When such a current collector is used, the adhesion between the current collector and the active material layer can be further improved.

If a metal foil is compressed using a roller that is not polished, stress concentrates on the raised part of the opening edge of the recess, causing cracks on the roller peripheral surface, and reducing the roller life. There is a risk. [Example 9]

A roller 28 was produced in the same manner as in Example 8 except that diamond particles having an average particle diameter of 30 Hm were used instead of diamond particles having an average particle diameter of 8 [I m.

(Example 10)

A roller 28 was produced in the same manner as in Example 8 except that diamond particles having an average particle diameter of 53 Hm were used instead of diamond particles having an average particle diameter of 8 Hm.

(Example 11)

A roller 28 was produced in the same manner as in Example 8 except that diamond particles having an average particle size of 74 Hm were used instead of diamond particles having an average particle size of 8 Hm. At this time, the average surface roughness of the roller 28 was a force that could not be made smaller than 0.8a.

For the roller 28 obtained in Examples 8 to 11, the remaining state of abrasive particles (diamond particles) on the circumferential surface of the roller 28 after diamond polishing, the average surface roughness of the circumferential surface of the roller 28 and the current collector preparation The damaged state of the 28 circumference of the roller was judged. The residual state and the damaged state were determined by observation with an electron microscope. The results are shown in Table 3.

[0148] [Table 3]

[0149] From Table 3, when polishing is performed using diamond particles having an average particle diameter of 8 Hm, the bulge of the opening edge 29a of the recess 29 is removed and the opening edge 29a is curved. It is clear that the particles remain. The diamond particles remaining in the recesses 29 could not be completely removed even by ultrasonic cleaning. In addition, when the current collector was produced with the diamond particles remaining in the recesses 29, the formation of the protrusions was sometimes insufficient.

[0150] If diamond particles with an average particle size of 74 in are used, the average surface roughness of the 28 circumferential surface of the roller The roughness was only finished to an average roughness of 0.8 in, and a portion where the bumps were not removed was observed. Further, when diamond particles having an average particle diameter of 30 m and 53 m are used, the opening edge 29a of the recess 29 is curved and the average surface roughness of the peripheral surface where the diamond particles remain is 0.4a or more. The following roller 28 was obtained.

[0151] Further, with respect to the roller 28 of Example 9 and Example 10, the diamond pad having an average particle diameter of 5 m was used as the abrasive on the opening edge 29a of the recess 29, and water was supplied while supplying the polishing pad. Polishing was carried out with a polishing machine equipped to form a groove 29χ having a width of about 1 μm and a depth of about 1 μm. Diamond particles with an average particle size of 5 inches are the smallest particles on the market that can control the variation in particle size distribution.

[0152] By forming such a groove 29χ, air or the like remaining in the concave portion when the convex portion is formed is smoothly discharged to the outside of the concave portion. As a result, the air remaining in the concave portion is compressed, the smooth plastic deformation of the convex portion is hindered by the pressure, and the convex portion is prevented from being uneven in shape, height and the like.

In the current collector, the height of the convex portion from the surface of the base material portion is determined in consideration of the life of the roller 28 in addition to the characteristics of the electrode to be finally obtained. In order to increase the service life of the roller 28, it is desirable to reduce the applied pressure at the pressure nip. Therefore, it is desirable to adjust so as to form a convex portion with a required height by reducing the applied pressure.

[0153] Using a roller 28 in which a groove 29y was formed, compression was performed with a length of 80 mm in the direction perpendicular to the conveying direction of the copper foil having a thickness of 26 m and a pressing force at the pressure nip of 80 kN. When a plastic deformation was generated, a convex part having an average height of 5.ππι from the surface of the base material part was formed.

On the other hand, when the copper foil was compressed in the same manner as above except that the rollers 28 of Examples 9 and 10 in which the grooves 29y were not formed were used, the average height from the surface of the base material portion was 3.4. A convex part of 11 m was formed. It was found that when solid or liquid lubricants were used for releasability, wear and lubrication, the height of the protrusions became even larger and the shape became uniform.

[Example 12] In the same manner as in Example 9, a recess 29 was formed on the peripheral surface of a ceramic recess-forming roller having a diameter of 25 mm, and a roller 28 was produced. The roller 28 was mounted as the roller 4 in the current collector manufacturing apparatus 35 shown in FIG. Copper foil with a thickness of 18 ^ m, a width of 80 mm in the direction perpendicular to the conveying direction and a length of 100 m is supplied to the press-fitting nipping part 34 and subjected to compression processing under a pressure of 80 kN to cause partial plastic deformation. The current collector 20 shown in Fig. 8 was made /

[Example 13]

A current collector 20 was produced in the same manner as in Example 12 except that the diameter of the recess forming roller was changed to 50 mm.

(Example 14)

A current collector 20 was produced in the same manner as in Example 12 except that the diameter of the recess forming roller was changed to 100 mm.

(Example 15)

A current collector 20 was produced in the same manner as in Example 12 except that the diameter of the recess forming roller was changed to 150 mm.

[0156] With respect to the current collector 20 obtained in Examples 12 to 15; the average height of the protrusions 22 and the difference between the maximum value and the minimum value of the protrusions 22 were determined by electron microscope observation. The average height of the convex portion is an average value of 100 convex portions 22. Further, regarding the roller 28 after the current collector 20 was produced, the damaged state of the recess 29 was visually observed. The height of the convex portion 20 is had contact to the cross-sectional view shown in FIG. ^7, in the direction perpendicular to the surface 21a of the base 21, the length from the surface 21a to the end surfaces of the projections 20. The results are shown in Table 4.

[0157] [Table 4] Roller diameter Average height of convex part Maximum height of convex part and concave part of mouth

(mm) () Damage state of minimum difference (ii m) Example 1 2 2 5 8 .0 4 .2 Yes Example 1 3 5 0 7 .4 1 .8 Yes Example 1 4 1 0 0 4 1 1. 1 «Example 1 5 1 5 0 2. 1 1. 2 1 As is apparent from Table 2, when the roller diameter was 25 mm, the average height of the convex portions 22 was 8 m. However, a relatively large stagnation occurred in the roller 28 itself, and the variation in the height of the convex portion 22 was large. In addition, the rotation of the roller 28 was uneven, and it was assumed that continuous machining was difficult.

When the roller diameter was 50 mm, the average height of the convex portion 22 was 7.4 111. Not a little deflection of the roller 28 was observed, and the height variation of the convex portion 22 was about ± 1 m. Further, when the concave portion 29 of the roller 28 was observed after the current collector 20 was produced, many cracks were generated. It is assumed that the roller diameter has a great influence on the life of the roller 28.

[0159] When the roller diameter was 100 mm, the average height of the convex portion 22 was 4.1 m, and the variation in the height of the convex portion 22 was ± 1 μm or less. Further, when the concave portion 29 of the roller 28 was observed after the current collector 20 was produced, no crack was observed. Furthermore, the force that produced current collector 20 of 500 m and 1000 m.

When the roller diameter was 150 mm, the average height of the convex portion 22 was 2. l ^ m, and the variation in the height of the convex portion 22 was ± 1 μm or less. When the concavity 29 of the roller 28 was observed after the current collector 20 was produced, the crack showed a force that was not recognized. Furthermore, the force that produced current collector 20 to 1000 m. However, it was found that in order to obtain the convex portion 22 having a sufficient height, it was necessary to increase the applied pressure very much, and for that purpose, it was necessary to increase the equipment size.

[0160] Based on the results shown in Tables 3 and 4, it was found that the roller 28 produced in Example 14 can be used suitably. For the production of the roller 28, diamond particles having an average particle diameter of 30 m are used in the polishing process, grooves 29x are formed in the opening edge 29a of the recess 29, and the average surface roughness of the roller peripheral surface is 0.4a. The Ronore diameter was set to 100 mm.

Further, in the current collector 20 produced in Examples 11 to 14; the boundary portion 22a between the base material portion 21 and the convex portion 22 is formed of a curved surface, and the sectional force of the convex portion 22 shown in FIG. It has a shape. As a result, the workability during compression processing and the releasability of the current collector 20 from the roller 28 are improved, and the convex portion 22 fits tightly into the concave portion 29 of the roller 28 and peels from the current collector 20. I was able to prevent. [0161] When the electrode group is formed of a positive electrode plate having a positive electrode active material supported on a current collector 20 having many protrusions 22 that are easily peeled off, the current collector 20 causes wrinkling of the positive electrode plate in the process of repeated charge and discharge. As a starting point, it was found that the positive electrode active material peeled off. This is considered to be caused by a variation in the mechanical strength of the current collector 20.

In this way, by processing using a pair of rollers, it is possible to apply pressure with a very small contact area and to increase the applied pressure. As a result, the current collector manufacturing apparatus 35 can be downsized.

[0162] (Example 16)

A roller 28A having the same configuration as that of the roller 28 shown in FIG. 9 except that the opening shape of the recess 29 is substantially rhombus was produced as follows. The aperture shape is approximately rhombus by laser processing using YAG laser on the peripheral surface of a 50 mm diameter cemented carbide recess forming roller, the long diagonal of the rhombus is 20 m long and the depth is approximately 10 mm. A recess which is m was formed. The laser was operated with a laser frequency of 1 kHz.

[0163] At the edge of the opening of the recess formed as described above, a bulge consisting of a groove and a bulge was formed, and the surface roughness of the roller partially increased. In particular, when the opening shape of the concave portion was a rhombus, directionality occurred in the grooves and bulges, and the surface shape deteriorated as a whole. For this reason, diamond particles having an average particle diameter of 8 m were used as abrasive grains, and polishing was performed with a polishing machine equipped with a polishing pad while supplying water. Polishing was performed until the average surface roughness of the roller peripheral surface reached 0.4a. As a result, the bulges were removed, and the recesses 29 having the curved edges 29a were formed to produce the rollers 28A.

[0164] The surface roughness of the roller 28A is approximately the same as the surface roughness of the metal foil as the raw material. Therefore, in the current collector obtained after compression processing, the tip surface of the convex portion maintains the surface roughness of the original metal foil, and the surface of the base material portion is subjected to compression processing by the roller 28A. The surface roughness is substantially the same as the surface roughness. That is, the entire surface of the current collector has substantially the same surface roughness. When such a current collector is used, the adhesion between the current collector and the active material layer can be further improved.

[0165] Note that, when the compression processing of the present invention is performed on the metal foil using a roller that is not subjected to polishing, stress concentrates on the raised portion of the opening edge of the recess, which becomes the starting point of the crack on the roller peripheral surface, Roller life may be reduced. In particular, when the opening shape is almost diamond-shaped, the two sharp corners are stress concentrated due to the shape and immediately become the starting point of the crack on the peripheral surface of the roller 28A, and also in the propagation path of the crack between the adjacent recesses 29. As a result, it was found that the roller life was greatly reduced.

[Example 17]

A roller 28A was produced in the same manner as in Example 16 except that diamond particles having an average particle diameter of 30 am were used instead of diamond particles having an average particle diameter of 8 m.

(Example 18)

A roller 28A was produced in the same manner as in Example 16 except that diamond particles having an average particle size of 53 / m were used instead of diamond particles having an average particle size of 8 μm.

(Example 19)

A roller 28A was produced in the same manner as in Example 16 except that diamond particles having an average particle size of 74 and im were used instead of diamond particles having an average particle size of 8 m. At this time, the average surface roughness of the roller 28A could not be made smaller than 0.8a.

Examples 16 to: Regarding the roller 28A obtained in 19, the residual state of abrasive particles (diamond particles) on the peripheral surface of the roller 28A after diamond polishing, the average surface roughness of the peripheral surface of the roller 28A and the production of the current collector The damaged state of the rear surface of the roller 28A was judged. The residual state and the damaged state were determined by observation with an electron microscope. The results are shown in Table 5.

[0167] [Table 5]

[0168] From Table 5, when polishing was performed using diamond particles having an average particle diameter of 8 m, the recesses 29 were opened. It is clear that the ridges on the lip 29a are removed, and the diamond particles remain in the recesses 29 where the opening edge 29a is curved. The diamond particles remaining inside the recess 29 could not be completely removed even by ultrasonic cleaning. In addition, when the current collector was produced with the diamond particles remaining in the recesses 29, the formation of the protrusions was sometimes insufficient.

[0169] In addition, when diamond particles with an average particle size of 74 in were used, the average surface roughness of the roller 28A peripheral surface was only finished to an average roughness of 0.8 in, and a portion where the bumps were not removed was observed. . Further, when diamond particles having an average particle diameter of 30 m and 53 m are used, the opening edge 29a of the recess 29 is curved, and the average surface roughness of the peripheral surface where the diamond particles remain is 0.4a or more. The following roller 28A was obtained.

[0170] Further, with regard to the roller 28A of Examples 17 and 18, by using diamond particles having an average particle diameter of 5 m as an abrasive on the opening edge 29a of the recess 29 and supplying water, a polishing machine provided with a polishing pad Polishing was performed to form a groove 29χ having a width of about 1 μm and a depth of about 1 μm. Diamond particles with an average particle size of 5 m are the smallest particles on the market that can control the variation in particle size distribution.

[0171] By forming such a groove 29x, air or the like remaining in the concave portion when the convex portion is formed is smoothly discharged to the outside of the concave portion. As a result, the air remaining in the concave portion is compressed, the smooth plastic deformation of the convex portion is hindered by the pressure, and the convex portion is prevented from being uneven in shape, height and the like.

In the current collector, the height of the convex portion from the surface of the base material portion is determined in consideration of the life of the roller 28A in addition to the characteristics of the electrode to be finally obtained. In order to increase the service life of the roller 28A, it is desirable to reduce the applied pressure at the pressure nip. Therefore, it is desirable to adjust so as to form a convex part with the required height by reducing the applied pressure. In particular, when the opening shape is approximately diamond-shaped, in order to obtain a sufficient height, a higher pressing force is required than when the opening shape is approximately circular. In addition, it was found that the height was reduced by about 15% to 23% even when pressed under the same conditions into a nearly circular shape with the same area projected from the plane. This is presumed to be due to the resistance force caused by the narrowness of the cross-sectional shape of the flesh from the long-axis cross section of the rhombus. [0172] Using a roller 28A in which a groove 29y was formed, compression processing was performed with the length in the direction perpendicular to the conveying direction of the 18m thick copper foil being 80mm and the applied pressure at the pressure nip being 80kN. When plastic deformation occurred, convex portions having an average height from the surface of the base material portion of 7.Ιπι were formed.

On the other hand, when pressing was performed in the same manner as described above except that the roller 28 ローラ having no groove 29y was used, a convex portion having an average height of 5.5 m from the surface of the substrate portion was formed. It was. When using solid or liquid lubricants for releasability and wear / lubrication, the height of the protrusions becomes even larger and the shape becomes uniform.

[Example 20]

In the same manner as in Example 17, a recess 29 was formed on the peripheral surface of a ceramic recess-forming roller having a diameter of 25 mm, and a roller 28A was produced. The roller 28A was mounted as the rollers 4 and 5 in the current collector manufacturing apparatus 35 shown in FIG. 3 to form the press-contacting dip portion 34a. Copper foil with a thickness of 26 111, a width of 80 mm in the direction perpendicular to the transport direction and a length of 100 m is supplied to the press-fitting nip part 34a, and compression processing is performed under a pressure of 80 kN to cause partial plastic deformation. Thus, a current collector 23 shown in FIG. 10 was produced.

[Example 17]

A current collector 23 was produced in the same manner as in Example 20 except that the diameter of the recess forming roller was changed to 50 mm.

(Example 22)

A current collector 23 was produced in the same manner as in Example 20, except that the diameter of the recess forming roller was changed to 100 mm.

(Example 23)

A current collector 23 was produced in the same manner as in Example 20 except that the diameter of the recess forming roller was changed to 150 mm.

[0175] For the current collector 23 obtained in Examples 20 to 23, the average height of the convex portions 25x and 25y (hereinafter referred to as "convex portion 25") and the difference between the maximum value and the minimum value of the convex portion 25 Was obtained by electron microscope observation. The convex average height is an average value of 100 convex portions 25. Further, the damaged state of the recess 29 was visually observed on the roller 28A after the current collector 23 was produced. The convex part 25 In the cross-sectional view shown in FIG. 8, the height is the length from the surface 24 a to the tip surface of the convex portion 25 in the direction perpendicular to the surface 24 a of the base material portion 24. The results are shown in Table 6.

[Table 6]

[0177] As is apparent from Table 6, the average height of the convex portions 25 was 10 m at a roller diameter of 25 mm. However, the roller 28A itself had relatively large stagnation, and the variation in the height of the convex part 25 was large. In addition, the rotation of the roller 28A was uneven, and it was assumed that continuous machining was difficult.

When the roller diameter is 50 mm, the average height of the convex portion 25 is 8.2 mm. The deflection of the force roller 28A is not a little, and the height variation of the convex portion 25 is about ± 1 m. Further, when the concave portion 29 of the roller 28A was observed after the current collector 23 was produced, many cracks were generated. From these facts, it is estimated that the roller diameter has a great influence on the life of the roller 28.

[0178] When the roller diameter was 100 mm, the average height of the convex portion 25 was 7.1 μm, and the variation in the height of the convex portion 25 was ± 1 μm or less. In addition, when the concave portion 29 of the roller 28A was observed after the current collector 23 was produced, the crack showed a force that was not recognized. In addition, the force that produced current collector 23 of 500 m and 1000 m.

When the roller diameter was 150 mm, the average height of the convex part 25 was 4.3 m, and the variation in the height of the convex part 25 was ± 1 m or less. When the concavity 29 of the roller 28A was observed after the current collector 23 was produced, no cracks were observed. Furthermore, the force with which the current collector 23 was produced 1000 m. However, in order to obtain the convex part 25 having a sufficient height, it was found that the applied pressure had to be very large, and for that purpose, the equipment size had to be increased. [0179] Based on the results shown in Table 5 and Table 6, it was found that the roller 28A produced in Example 22 can be used suitably. For the production of roller 28A, diamond particles having an average particle diameter of 30 mm are used in the polishing process, grooves 29x are formed in the opening edge 29a of the recess 29, and the average surface roughness of the roller peripheral surface is 0.4a. The roll diameter was set to 100 mm.

Further, in the current collector 23 produced in Examples 20 to 23, the boundary portion 25a between the base material portion 24 and the convex portion 25 is composed of a curved surface, and the sectional force of the convex portion 25 shown in FIG. 10 is tapered. have. As a result, the workability during compression processing and the releasability of the current collector 23 from the roller 28A are improved, and the convex portion 25 is tightly fitted into the concave portion 29 of the roller 28A and peeled off from the current collector 23. We were able to prevent.

[0180] When the electrode group is composed of a negative electrode plate having a negative electrode active material supported on a current collector 23 having many convex portions 25 that are easily peeled off, the current collector 23 causes wrinkling of the negative electrode plate in the process of repeated charge and discharge. As a starting point, it was found that the negative electrode active material peeled off. This is considered to be caused by a variation in the mechanical strength of the current collector 23.

[0181] (Example 24)

The ceramic roller 28 shown in FIG. 9 in which the shape of the opening is almost circular, the depth 8 111, and a plurality of recesses 29 having an opening diameter of 10 m is formed is used as the rollers 4 and 5 in the current collector manufacturing apparatus 35 shown in FIG. As fitted. A strip-shaped aluminum foil with a thickness of 15 πι, which is a metal foil for current collector 10, is passed through the pressure-welding two-ply part 34a (Fig. 11) of the current collector manufacturing apparatus 35 under a line pressure of 10 kN and partly passed. Non-compression processing was performed to produce a positive electrode current collector 80 shown in FIG. FIG. 16 is a drawing schematically showing a configuration of a current collector 80 which is one of the embodiments of the present invention. FIG. 16A is a perspective view of the current collector 80. FIG. 16 (b) is a longitudinal sectional view of the current collector 80.

[0182] The obtained current collector 80 includes a base part 81 made of aluminum, and a substantially circular convex part 82x, 82y having a height of 5 m regularly formed on both surfaces of the base part 81 in the thickness direction. (Hereinafter referred to as “convex portion 82”), and the thickness of the base material portion 81 is t force 2 111, and the maximum thickness t force is ^ O ^ m.

7 8

Current collector. In the width direction (longitudinal direction) X, the protrusions 82 are arranged in a row at a pitch P. A row unit 83 arranged in a row is formed. In the lateral direction Y, the row units 83 are arranged in parallel by the pitch P. Furthermore, in line unit 83 and adjacent line unit 83,

6

The convex portions 82 are arranged so as to be shifted by 0.5 P in the width direction X. like this

Five

The arrangement pattern of the convex portions 82 is a close-packed arrangement.

In current collector 80, boundary portion 82a between base material portion 81 and convex portion 82 was formed of a curved surface. As a result, the workability during the compression process and the releasability of the current collector 80 from the roller 28 are improved. At the same time, since the substantially circular protrusions 82 are arranged in a close-packed manner, the current collector 80 has sufficient durability against the tensile stress applied in the longitudinal direction X. For this reason, it was possible to prevent the current collector 80 from being locally deformed or sagged during manufacture of the current collector 80 or during processing of the current collector 80.

[0184] Further, when the surface roughness of the current collector 80 was measured with a surface roughness meter, the surface 81a of the base member 81 was found to have a smaller surface roughness than the aluminum foil before processing. The surface roughness of the surface 81 a of the base material portion 81 was almost the same as the surface roughness of the ceramic roller 28.

On the other hand, the surface roughness of the tip surface of the protrusion 82 was almost the same as that of the aluminum foil before processing. Further, when the tip surface of the projection 82 was observed with a scanning electron microscope, the same fine scratches as those observed on the aluminum foil before processing were observed.

[0185] Further, when the crystal orientation analysis of the current collector 80 by the backscattered electron diffraction image (EBSP) method was performed, the surface 81a of the base material portion 81 and the inside of the convex portion 82 were aluminum foil before processing. It was found that the crystal grains were more vigorous than. In addition, as a result of measuring the tensile strength of the current collector 80, the tensile strength did not decrease even though the base material portion 81 was thinner than the aluminum foil before processing. It is estimated that the tensile strength was improved by curing.

From the above analysis results, by applying the above processing to the aluminum foil, the convex portion 82 is not compressed, and the surface 81a of the base member 81 is compressed, and the current collector It is considered that 80 was obtained.

[0186] The positive electrode mixture slurry was applied to both sides of the current collector 80 obtained as described above, dried, and the total thickness was

The positive electrode was pressed to 126 m, and the positive electrode active material layer on one side had a thickness of 58 μm. This was slitted to a predetermined width to produce a positive electrode plate. The positive electrode mixture slurry consists of 100 parts by weight of lithium cobaltate in which a part of cobalt is substituted with nickel and manganese, 2 parts by weight of acetylene black (conductive material), 2 parts by weight of active material of polyvinylidene fluoride (binder) and appropriate amount N-methyl-2-pyrrolidone was stirred and kneaded in a double-arm kneader.

[0187] In the current collector 80, as shown in FIG. 16, the substantially circular convex portions 82 are arranged in a close-packed manner, and the boundary portion 82a between the substrate portion 81 and the convex portion 82 is formed of a curved surface. Sufficient durability against tensile stress applied in the longitudinal direction X. Therefore, the current collector 80 is locally deformed or deformed in a process of applying a positive electrode mixture slurry to the current collector 80, drying and pressing to produce a positive electrode, and slitting the positive electrode to a predetermined width. As a result, it was possible to prevent the positive electrode active material layer from falling off.

[Example 25]

The ceramic roller 28A shown in FIG. 9 in which the shape of the opening is approximately rhombus, the depth is 10 111, and a plurality of the concave portions 29 of the longer diagonal of the rhombus 20 m is formed in the current collector manufacturing apparatus 35 shown in FIG. Mounted as rollers 4 and 5. A metal foil 10 for current collector, a strip-shaped copper foil with a thickness of 12 m, is passed through the pressure welding two-ply part 34a (Fig. 11) of current collector manufacturing equipment 35 under a pressure of 10 kN and compressed. Thus, plastic deformation was partially caused to produce a negative electrode current collector 85 shown in FIG. FIG. 17 is a drawing schematically showing a configuration of a current collector 85 which is one embodiment of the present invention. FIG. 17A is a perspective view of the current collector 85. FIG. 17B is a longitudinal sectional view of the current collector 85.

[0189] The obtained current collector 85 includes a base material portion 86 made of copper, and a substantially rhombic convex portion 87x having a height of 6 m, which is regularly formed on both surfaces of the base material portion 86 in the thickness direction. 87y (hereinafter referred to as “convex portion 87”), and a current collector in the form of a strip with a thickness t force of the base material portion 86, 1 m, and a maximum thickness t force S18 m

9 10

It was a body. In the width direction (longitudinal direction) X, row units 88 in which convex portions 86 are arranged in a line at a pitch P are formed. In short direction Y, line unit 88 is flat at pitch P.

Arranged in 8 rows. Further, in the row unit 88 and the adjacent row unit 88, the convex portions 87 are arranged so as to be shifted by 0.5 · 5P in the width direction X. Such an arrangement pattern of the protrusions 87 is a close-packed arrangement.

[0190] In current collector 85, boundary portion 86a between base material portion 86 and convex portion 87 is formed of a curved surface. It was. This improves the workability during compression processing and the releasability of the current collector 85 from the roller 28. At the same time, since the approximately rhombic projections 87 are arranged in a close-packed manner, the current collector 85 has sufficient durability against the tensile stress applied in the longitudinal direction X. For this reason, it was possible to prevent the current collector 85 from being locally deformed or sagged during manufacture of the current collector 85 or during processing of the current collector 85.

[0191] Further, when the surface roughness of the current collector 85 was measured with a surface roughness meter, the surface 86a of the base material portion 86 was found to have a smaller surface roughness than the copper foil before processing. The surface roughness of the surface 86a of the base material portion 86 was almost the same as the surface roughness of the ceramic roller 28.

On the other hand, the surface roughness of the tip surface of the convex portion 87 was almost the same as the copper foil before processing. Further, when the tip surface of the convex portion 87 was observed with a scanning electron microscope, the same fine scratches as those observed on the copper foil before processing were observed.

[0192] Further, when the crystal orientation analysis of the current collector 85 by the backscattered electron diffraction image (EBSP) method was performed, the surface 86a of the base material portion 86 and the inside of the convex portion 87 were formed on the copper foil before processing. In comparison, it was found that the crystal grains were weak. In addition, as a result of measuring the tensile strength of the current collector 85, no decrease in tensile strength was observed even though the thickness of the base material portion 86 was thinner than the copper foil before processing. It is estimated that the tensile strength was improved by work hardening.

From the above analysis results, by performing the above-described processing on the copper foil, plastic deformation accompanying compression processing occurs in the portion of the convex portion 87, and the surface 86a of the base material portion 86 is subjected to compression processing to collect current. It is probable that body 85 was obtained.

[0193] The current collector 85 obtained above was mounted inside a vacuum vapor deposition apparatus equipped with an electron beam heating means. Using silicon with a purity of 99.9999% as a target, vapor deposition was carried out while introducing oxygen with a purity of 99.7%.

0.5 layers were formed in a column shape. This was slit to a predetermined width to prepare a negative electrode plate.

As shown in FIG. 17 (a), the current collector 85 has substantially rhombic convex portions 87 formed on both surfaces thereof in a close-packed arrangement, and the boundary portion between the base material portion 86 and the convex portion 87. 87a is a curved surface. For this reason, when the negative electrode active material is deposited in the longitudinal direction X of the current collector 85, it can be efficiently attached to the surface of the convex portion 87. In addition, the current collector 85 has sufficient durability against the tensile stress applied in the longitudinal direction X. For this reason, in the step of producing the strip-shaped current collector 85, the step of depositing the negative electrode active material on the surface of the current collector 85 to produce the negative electrode plate, the step of slitting the negative electrode plate to a predetermined width, etc. Thus, local deformation and stagnation of the current collector 85 are prevented. At the same time, the negative electrode active material could be prevented from falling off.

[0195] (Example 26)

The ceramic roller 28 shown in FIG. 9 having a substantially circular opening, a plurality of recesses 29 having a depth of 10 111 and an opening diameter of 10 m is used as rollers 4 and 5 in the current collector manufacturing apparatus 35 shown in FIG. Installed. The metal foil 10 for the current collector, which is 18 ΐη thick, is passed through the pressure welding two-ply part 34a (Fig. 11) of the current collector manufacturing device 35 under a pressure of 10 kN and compressed. To partially generate plastic deformation to produce a negative electrode current collector 80 shown in FIG.

Yes

[0196] The obtained current collector 80 includes a base material portion 81 made of copper, and a substantially circular convex portion 82x having a height of 8 m, which is regularly formed on both surfaces of the base material portion 81 in the thickness direction. 82y (hereinafter referred to as “convex portion 82”), and a base-shaped portion 81 having a thickness t force 0 111 and a maximum thickness t force ¾6 m.

7 8

It was a body. In the width direction (longitudinal direction) X, the protrusions 82 are arranged in a line at a pitch P.

Five

A row unit 83 is formed. In short direction Y, line unit 83 is flat at pitch P.

Arranged in 6 rows. Further, in the row unit 83 and the adjacent row unit 83, the respective protrusions 82 are arranged so as to be shifted by 0.5 · 5P in the width direction X. Such a convex part 82

Five

This arrangement pattern is a close-packed arrangement.

[0197] In the current collector 80, the boundary portion 82a between the base material portion 81 and the convex portion 82 was formed of a curved surface. As a result, the workability during the compression process and the releasability of the current collector 80 from the roller 28 are improved. At the same time, since the substantially circular protrusions 82 are arranged in a close-packed manner, the current collector 80 has sufficient durability against the tensile stress applied in the longitudinal direction X. For this reason, it was possible to prevent the current collector 80 from being locally deformed or sagged during manufacture of the current collector 80 or during processing of the current collector 80.

[0198] Further, when the surface roughness of the current collector 80 was measured with a surface roughness meter, the surface 81a of the base member 81 was found to have a smaller surface roughness than the copper foil before processing. Surface of substrate 81 surface roughness of surface 81a This was almost the same as the surface roughness of the ceramic roller 28.

On the other hand, the surface roughness of the tip surface of the convex portion 82 was almost the same as the copper foil before processing. Further, when the tip surface of the convex portion 82 was observed with a scanning electron microscope, the same fine scratches as those observed on the copper foil before processing were observed.

[0199] Further, when the crystal orientation analysis of the current collector 80 by the backscattered electron diffraction image (EBSP) method was performed, the surface 81a of the base material portion 81 and the inside of the convex portion 82 were formed on the copper foil before processing. In comparison, it was found that the crystal grains were weak. In addition, as a result of measuring the tensile strength of the current collector 80, no decrease in tensile strength was observed even though the thickness of the base material portion 81 was thinner than the copper foil before processing. It is estimated that the tensile strength was improved by work hardening.

From the above analysis results, by performing the above-described processing on the copper foil, plastic deformation occurs in the portion of the convex portion 82 along with the compression processing, and the surface 81a of the base material portion 81 is subjected to the compression processing. It is considered that current collector 80 was obtained.

[0200] The current collector 85 obtained above was mounted inside a vacuum vapor deposition apparatus equipped with an electron beam heating means. Using silicon with a purity of 99.9999% as a target, vapor deposition was carried out while introducing oxygen with a purity of 99.7%.

[0201] As shown in Fig. 16 (a), the current collector 80 has substantially circular convex portions 82 formed on both surfaces thereof in a close-packed arrangement, and a boundary portion between the base material portion 81 and the convex portions 82. 82a is a curved surface. For this reason, when the negative electrode active material is deposited in the longitudinal direction X of the current collector 80, the negative electrode active material can be efficiently attached to the surface of the convex portion 82.

In addition, the current collector 80 has sufficient durability against the tensile stress applied in the longitudinal direction X. For this reason, in the step of manufacturing the strip-shaped current collector 80, the step of depositing the negative electrode active material on the surface of the current collector 80 to prepare the negative electrode plate, the step of slitting the negative electrode plate to a predetermined width, etc. Thus, local deformation and stagnation of the current collector 85 are prevented. At the same time, the negative electrode active material could be prevented from falling off.

[0202] Using the positive electrode plate obtained in Example 24 and the negative electrode plate obtained above, a cylindrical nonaqueous electrolyte secondary battery 40 shown in Fig. 12 was produced. First, positive plate 50, separator 52, negative plate 5 1 and separator 52 were superposed in this order, and wound in a spiral shape to produce electrode group 41. Further, as shown in FIG. 9, an electrode group 14 was produced in which a positive electrode plate 15 and a negative electrode plate 17 were spirally wound through a separator 19. The electrode group 41 was housed together with an insulating plate 44 in a bottomed cylindrical battery case 47. A negative lead (not shown) derived from the lower part of the electrode group 41 is connected to the bottom of the battery case 47, and then a positive lead 42 led from the upper part of the electrode group 41 is connected to the sealing plate 45. An electrolyte solution (not shown) made of a nonaqueous solvent was injected. Thereafter, a sealing plate 45 having a sealing gasket 46 attached to the periphery thereof is inserted into the opening of the battery case 47, and the opening of the battery case 47 is folded inward to seal it. A secondary battery 40 was produced.

[0203] After the electrode group 41 wound in the spiral shape in the non-aqueous secondary battery 40 was produced, the electrode group 41 was disassembled and observed. If both the positive electrode plate 50 and the negative electrode plate 51 were broken, it was active. There were no defects such as falling off of the material layer. Furthermore, when the non-aqueous secondary battery 40 and the electrode group 41 were disassembled after 300 cycles without any cycle deterioration, the force that caused the non-aqueous secondary battery 40 to charge and discharge for 300 cycles, lithium precipitation, active material layer dropping, etc. No defects were found.

[0204] This is because the thin film of the active material layer is formed in a columnar shape on the surface of the convex portion that is not subjected to compression processing, so that the thin film of the active material layer during lithium occlusion and the active material layer during lithium release It is considered that good battery characteristics were maintained by the effect of reducing the volume change due to the shrinkage of the thin film.

[0205] As described in the above embodiments, the electrode plate for a non-aqueous secondary battery according to the present invention is such that the boundary portion between the base portion and the convex portion of the current collector is a curved surface. Good workability during compression processing and release property of current collector. In addition, since the tip surface of the convex portion of the current collector is not compressed, there is no processing strain due to the processing, and the surface accuracy of the convex tip surface is good. A thin film active material layer can be formed. Further, since the convex portion is formed by plastic deformation accompanying compression processing, the surface roughness of the surface of the convex portion tip is not reduced, and the initial surface roughness is maintained. Therefore, it is considered that the adhesion with the thin film active material layer is high.

[0206] From this point of view, the adhesion between the flat surface of the convex portion and the electrode active material mixture layer was further increased. For this purpose, it is considered very effective to make the surface of the current collector before processing rougher in advance.

In addition, the active material layer in the non-aqueous secondary battery of the present invention is preferably formed in a columnar shape on the tip surface of the convex portion. As a result, the volume change due to the expansion of the active material layer during lithium occlusion accompanying the charge / discharge of the non-aqueous secondary battery and the contraction of the active material layer during lithium release is alleviated. As a result, a non-aqueous secondary battery with high capacity and high reliability is obtained that is less likely to cause defects such as electrode plate breakage and dropping of the active material layer due to charge and discharge.

Industrial applicability

According to the method for manufacturing a current collector and an electrode plate for a non-aqueous secondary battery according to the present invention, the strength of the current collector for producing the electrode plate is ensured, and the convex portions formed on the current collector Since an electrode active material can be efficiently carried on the substrate and a highly reliable non-aqueous secondary battery can be obtained, a higher capacity is desired as electronic devices and communication devices become more multifunctional. It is useful as a power source for portable electronic devices.

Claims

The scope of the claims

[I] Using a pair of processing means provided so as to form a pressure-welding two-ply portion through which the surfaces can be pressed against each other and through which a sheet-like material can pass, and a plurality of recesses are formed on at least one surface. A current collector for a non-aqueous electrolyte secondary battery in which a metal foil for electrical current is passed through a pressure nip of a processing means and subjected to compression to form a plurality of convex portions on at least one surface of the metal foil for current collector. Manufacturing method.

[2] The manufacturing method according to claim 1, wherein the surface roughness of the tip surface of the convex portion is substantially the same as the surface roughness of the metal foil for current collector before compression processing.

[3] The cross section of the recess in the direction perpendicular to the processing means surface has a tapered shape in which the width of the cross section in the direction parallel to the processing means surface gradually decreases from the processing means surface toward the bottom of the recess. The manufacturing method according to claim 1 or 2.

[4] Volume force of the convex portion Claim that compresses so as to be less than or equal to the volume of the internal space of the concave portion;

4. The production method according to any one of 3.

[5] Volume force of convex portion The manufacturing method according to any one of claims 1 to 4, wherein the compression processing is performed so that the volume of the internal space of the concave portion is 85% or less.

6. The manufacturing method according to any one of claims 1 to 5, wherein the boundary between the recess and the surface of the processing means is a curved surface in the processing means having a plurality of recesses formed on the surface.

[7] Curved shape force at the boundary between the recess and the surface of the processing means Formed by forming the recess by laser processing and removing the bulge at the boundary between the recess and the surface of the processing means generated by laser processing The manufacturing method according to claim 6.

[8] The production method according to claim 7, wherein the bumps are removed by polishing with diamond particles having an average particle diameter of 30,1 m or more and less than 53 μm.

[9] A plurality of grooves having a width of 1 μm or less and a depth of 1 μm or less are formed at the boundary between the recess and the surface of the processing means! The manufacturing method as described.

[10] The production method according to claim 9, wherein the grooves are formed by polishing with diamond particles having an average particle diameter of 5 am or less.

[II] The manufacturing method according to claim 1, wherein the pair of processing means is a pair of rollers, and a concave portion is formed on the surface of at least one of the rollers, and V;

[12] The surface coating layer containing cemented carbide, alloy tool steel or chromium oxide is formed on the surface of the roller on which the recess is formed and on the surface facing the inner space of the recess. Manufacturing method.

13. The method according to claim 12, wherein a protective layer containing an amorphous carbon material is formed on the surface of the surface coating layer.

[14] The surface coating layer and the protective layer are formed by physical vapor deposition using sputtering, physical vapor deposition using ion implantation, chemical vapor deposition using thermal evaporation, and plasma deposition. 14. The production method according to claim 12 or 13, wherein the production method is formed by at least one gas phase growth method selected from the group consisting of chemical vapor deposition methods to be used.

15. The production method according to any one of claims 1 to 10, wherein at least one roller force is a roller provided with a ceramic layer on the surface, and a recess is formed on the surface of the ceramic layer.

[16] The method according to any one of [1] to [10], wherein a lubricant is applied to the surface of the roller or the current collector metal foil and dried.

17. The production method according to claim 16, wherein the lubricant contains a fatty acid.

[18] A substrate portion surface comprising a substrate portion made of a metal foil for a current collector, and a plurality of convex portions formed so as to extend outward from at least one surface of the substrate portion Current collector for a non-aqueous electrolyte secondary battery in which the boundary between the convex portion and the convex portion is a curved surface.

[19] A non-aqueous electrolyte secondary battery current collector manufactured by the method for manufacturing a non-aqueous electrolyte secondary battery current collector according to any one of! A method for producing an electrode for a non-aqueous electrolyte secondary battery in which a positive electrode active material or a negative electrode active material is supported on the surface of a current collector for a water electrolyte secondary battery.

20. The method for producing a nonaqueous electrolyte secondary battery electrode according to claim 19, wherein the positive electrode active material or the negative electrode active material is supported on the convex surface of the current collector for the nonaqueous electrolyte secondary battery.

[21] A non-aqueous electrolyte secondary battery containing a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte,

21. A nonaqueous electrolyte secondary battery, wherein at least one of the positive electrode and the negative electrode is an electrode produced by the method for producing an electrode for a nonaqueous electrolyte secondary battery according to claim 19 or 20.