WO2014002997A1 - Electrolytic copper foil, manufacturing method therefor, negative electrode for lithium-ion secondary battery, and lithium-ion secondary battery - Google Patents
Electrolytic copper foil, manufacturing method therefor, negative electrode for lithium-ion secondary battery, and lithium-ion secondary battery Download PDFInfo
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- WO2014002997A1 WO2014002997A1 PCT/JP2013/067380 JP2013067380W WO2014002997A1 WO 2014002997 A1 WO2014002997 A1 WO 2014002997A1 JP 2013067380 W JP2013067380 W JP 2013067380W WO 2014002997 A1 WO2014002997 A1 WO 2014002997A1
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- copper foil
- electrolytic copper
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C9/00—Alloys based on copper
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D1/00—Electroforming
- C25D1/04—Wires; Strips; Foils
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/64—Carriers or collectors
- H01M4/66—Selection of materials
- H01M4/661—Metal or alloys, e.g. alloy coatings
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Definitions
- the present invention relates to an electrolytic copper foil having high strength and high conductivity, a method for producing the same, a negative electrode using the electrolytic copper foil, and a lithium ion secondary battery incorporating the negative electrode.
- a lithium (Li) ion secondary battery includes, for example, a positive electrode, a negative electrode having a negative electrode active material layer formed on the surface of a negative electrode current collector, and a non-aqueous electrolyte. Is used.
- the negative electrode of the lithium ion secondary battery is formed, for example, by applying carbon particles as a negative electrode active material layer on the surface of a negative electrode current collector made of a copper foil having smooth surfaces, drying, and pressing.
- a so-called “untreated electrolytic copper foil” manufactured by electrolysis is subjected to a rust prevention treatment.
- a negative electrode active material for a lithium ion secondary battery development of a next-generation negative electrode active material having a charge / discharge capacity that greatly exceeds the theoretical capacity of a carbon material is underway.
- a material containing a metal that can be alloyed with lithium such as silicon (Si) or tin (Sn) is expected.
- Patent Documents 1 to 11 describe an electrolytic copper foil used for a negative electrode current collector of a lithium ion secondary battery.
- an object of the present invention is to provide an electrolytic copper foil having high strength and high conductivity.
- Another object of the present invention is to provide a negative electrode using the electrolytic copper foil of the present invention having high strength (tensile strength) and high conductivity as a current collector, and a lithium ion secondary battery incorporating the negative electrode.
- the electrolytic copper foil of this invention can be preferably used also as a copper foil for circuit boards as uses other than the collector for batteries, for example.
- the electrolytic copper foil of the present invention has an average number of intersection points of an arbitrary line segment having a length of 500 nm and a twin plane which is a (111) ⁇ 3 grain boundary in a transmission electron microscope (TEM) observation image. It is.
- the average number of intersections between an arbitrary line segment having a length of 500 nm and a twin plane which is a (111) ⁇ 3 grain boundary in a transmission electron microscope (TEM) observation image is larger.
- a preferred range is 10 to 36.
- the method for producing an electrolytic copper foil of the present invention includes an electrolytic solution containing copper and sulfuric acid, containing 20 to 50 ppm of chlorine, 1 to 10 ppm of a thiourea compound, and 1 to 20 ppm of a water-soluble polymer compound as additives.
- the average number of intersections between an arbitrary line segment having a length of 500 nm and a twin plane which is a (111) ⁇ 3 grain boundary is 5 to 40 in a transmission electron microscope (TEM) observation image after electrolytic treatment with a plating solution.
- the electrolytic copper foil production method is for producing an electrolytic copper foil of 10 to 36.
- the electrolytic copper foil which raised tensile strength and electrical conductivity can be provided.
- the electrolytic copper foil of the present invention with increased tensile strength and conductivity as a current collector it is possible to provide a lithium ion secondary battery with increased battery capacity and improved charge / discharge characteristics of the secondary battery. .
- FIG. 1 is a TEM image according to the example.
- FIG. 2 is an explanatory diagram showing the intersection of the line segment and the (111) ⁇ 3 grain boundary by drawing a line segment on the TEM image according to the example.
- the electrolytic copper foil of the present embodiment is a copper foil suitable as a negative electrode current collector of a lithium ion secondary battery.
- the crystal structure of the cross section that is, an observation image with a transmission electron microscope (TEM) ⁇ hereinafter simply referred to as “TEM image”.
- TEM image The average number of intersections between an arbitrary line segment having a length of 500 nm and a twin plane that is a (111) ⁇ 3 grain boundary is 5 to 40, more preferably 10 to 36. is there.
- the average number of intersections between an arbitrary line segment having a length of 500 nm and a twin plane which is a (111) ⁇ 3 grain boundary is first shown in a TEM image as shown in FIG. An arbitrary line segment having a length of 500 nm is entered, and the number of intersections with the twin plane which is the (111) ⁇ 3 grain boundary is obtained. Next, three similar lines are drawn while rotating by 60 ° around the midpoint of the line segment, and the number of intersections between each line segment and the twin plane is obtained. This is a value obtained by averaging the number of intersections.
- a large number of (111) ⁇ 3 grain boundaries are introduced into a metal structure having many nano-sized crystal grains, and the average number of intersections between an arbitrary line segment having a length of 500 nm and a twin plane that is a (111) ⁇ 3 grain boundary
- the ratio By setting the ratio to 5 to 40, it is possible to set the conductivity suitable for use for a secondary battery while improving the tensile strength, which is a typical index of mechanical strength.
- the average particle diameter of the copper particles constituting the electrolytic copper foil is 5 to 200 nm.
- An average particle size of less than 5 nm is not preferable because the conductivity is low.
- it exceeds 200 nm the tensile strength decreases, which is not preferable.
- the electrolytic copper foil of the present embodiment preferably has a tensile strength of 500 to 900 MPa.
- the tensile strength is 500 to 900 MPa, it can be preferably used as a battery structural member and other electronic device material even when it is thinned.
- the tensile strength is less than 500 MPa, the strength of the structural member is insufficient, and when it exceeds 900 MPa, defects such as cracks are likely to occur during processing.
- the electrolytic copper foil of the present embodiment has a tensile strength of more preferably 600 to 800 MPa. When the pressure is 600 to 800 MPa, the durability is further enhanced and the battery capacity can be further increased.
- the electrolytic copper foil of this embodiment preferably has a conductivity of 60% IACS or higher.
- the conductivity By setting the conductivity to 60% IACS or more, it is possible to suppress heat generated when used as an electronic device while having sufficient conductivity.
- the electrical conductivity is 60% IACS or less, heat is generated due to electric resistance, or when used as a current collector for a lithium ion secondary battery, problems such as a decrease in output voltage due to IR drop occur.
- the electrolytic copper foil of the present embodiment has a conductivity of 70% IACS or more more preferably. When it is at least 70% IACS, the charge / discharge characteristics are further enhanced when used as a lithium ion secondary battery.
- the average number of intersections between an arbitrary line segment having a length of 500 nm and a twin plane which is a (111) ⁇ 3 grain boundary is 5 to 40, so that the above preferable tensile Strength and appropriate electrical conductivity can be realized.
- strength high electrical conductivity electrolytic copper foil of this embodiment is provided with the antirust process layer on the surface.
- the antirust treatment layer is, for example, a chromate treatment layer, or a Ni or Ni alloy plating layer, a Co or Co alloy plating layer, a Zn or Zn alloy plating layer, a Sn or Sn alloy plating layer, or the above various plating layers.
- It is an inorganic rust prevention treatment such as one provided with a chromate treatment layer, or an organic rust prevention treatment layer such as benzotriazole.
- a silane coupling agent treatment layer or the like may be formed.
- the inorganic rust prevention treatment, organic rust prevention treatment, and silane coupling agent treatment increase the adhesion strength with the active material when used as a lithium ion secondary battery, and also prevent the charge / discharge cycle efficiency of the battery from decreasing. Fulfill.
- the high-strength, high-conductivity electrolytic copper foil of the present embodiment is subjected to a roughening treatment on the surface on which the active material layer of the electrolytic copper foil is provided, and a rust-proofing treatment layer is provided on the surface subjected to the roughening treatment. Is provided.
- the electrolytic copper foil of the present embodiment is, for example, an insoluble anode made of titanium coated with a white metal element or an oxide element thereof using a sulfuric acid-copper sulfate aqueous solution as an electrolytic solution, and a titanium cathode provided facing the anode. While supplying the electrolytic solution between the drum and rotating the cathode drum at a constant speed, a direct current is passed between the two electrodes to deposit copper on the surface of the cathode drum, and the deposited copper is removed from the surface of the cathode drum. It is manufactured by a method of peeling and continuously winding.
- the electrolytic copper foil of the present embodiment can be produced, for example, by performing electrolytic treatment in a sulfuric acid-copper sulfate electrolytic plating solution.
- the current density during the electrolytic treatment is preferably 30 to 70 A / dm 2 .
- the copper concentration of the sulfuric acid-copper sulfate electroplating solution is, for example, in the range of 40 to 120 g / L, and preferably in the range of 60 to 100 g / L.
- the sulfuric acid concentration in the sulfuric acid-copper sulfate electroplating solution is, for example, in the range of 40 to 60 g / L.
- This sulfuric acid concentration is an important condition, and if it is less than this range, the conductivity of the plating solution will be lowered, so that the uniform electrodeposition of the copper foil will be reduced, and N (nitrogen) and S ( This is not preferable because the effect of the sulfur-containing additive is hardly exhibited, and the strength of the copper foil is reduced and the crystal orientation is randomized.
- the chlorine concentration of the sulfuric acid-copper sulfate electroplating solution for example, a range of 20 to 50 ppm is used. Moreover, both the organic additives A and B shown below are used.
- the organic additive A is an organic compound containing at least one N (nitrogen) atom and S (sulfur) atom in one molecule. By adding an appropriate amount of at least one organic additive A, a large number of (111) ⁇ 3 grain boundaries can be introduced into the metal structure of the produced electrolytic copper foil.
- the organic additive A is desirably a thiourea compound, and more desirably a thiourea compound having 3 or more carbon atoms. Examples of the organic additive A include thiourea (CH 4 N 2 S), N, N′-dimethylthiourea (C 3 H 8 N 2 S), N, N′-diethylthiourea (C 5 H 12 N 2 S).
- thiourea (C 5 H 12 N 2 S ), tetramethyl thiourea (C 5 H 12 N 2 S ), thiosemicarbazide Sid (CH 5 N 3 S), N- allyl thiourea (C 4 H 8 N 2 S ), ethylene thiourea (C 3 H 6 N 2 S) is a water-soluble thiourea or a thiourea compound such as a thiourea derivative.
- the additive A added to the electrolytic plating solution one or more selected from these thiourea compounds are used.
- Organic additives B include, for example, glue, gelatin, polyethylene glycol, polypropylene glycol, starch, high molecular polysaccharides such as cellulose water-soluble polymers (carboxyl methyl cellulose, hydroxyethyl cellulose, etc.), polyethylene imine, polyamine polymers, poly Water-soluble polymer compounds such as acrylamide.
- additive B to be added to the electroplating solution one or more selected from these water-soluble polymer compounds are used.
- organic additive B in addition to organic additive A a large number of (111) ⁇ 3 grain boundaries can be introduced into the metal structure of the produced electrolytic copper foil.
- a TEM image is obtained by performing electrolytic treatment with an electrolytic plating solution containing copper and sulfuric acid, containing 20 to 50 ppm of chlorine, 1 to 10 ppm of a thiourea compound, and 1 to 20 ppm of a water-soluble polymer compound.
- an electrolytic copper foil having an average number of intersection points between an arbitrary line segment having a length of 500 nm and a twin plane which is a (111) ⁇ 3 grain boundary can be produced.
- the heat resistance can be further improved by adding a transition metal element to the sulfuric acid-copper sulfate electroplating solution.
- the metal element to be added is preferably an element in which an oxide is stable in a sulfuric acid aqueous solution, and more preferably an element capable of stably taking a trivalent or higher polyvalent oxide.
- the average number of intersections between an arbitrary line segment having a length of 500 nm and a twin plane which is a (111) ⁇ 3 grain boundary in a TEM image is 5 to 40.
- the surface on the side where the electrolytic copper foil is in contact with the surface of the cathode drum at the time of manufacture is referred to as the S surface (glossy surface), and the opposite surface is referred to as the M surface (matt surface).
- the produced electrolytic copper foil for example, chromate treatment, Ni or Ni alloy plating, Co or Co alloy plating, Zn or Zn alloy plating, Sn or Sn alloy plating, or the above various types
- An inorganic rust prevention treatment such as a chromate treatment on the plating layer, or an organic rust prevention treatment such as benzotriazole.
- the silane coupling agent process etc. are given, for example, and it uses as an electrolytic copper foil for lithium ion secondary battery negative electrode collectors.
- the inorganic rust prevention treatment, organic rust prevention treatment, and silane coupling agent treatment increase the adhesion strength with the active material and prevent the charge / discharge cycle efficiency of the battery from being lowered.
- a roughening process is performed to the electrolytic copper foil surface, for example.
- a plating method, an etching method, or the like can be suitably employed.
- the plating method is a method of roughening the surface by forming a thin film layer having irregularities on the surface of the untreated electrolytic copper foil.
- an electrolytic plating method and an electroless plating method can be employed.
- a method of forming a plating film mainly composed of copper such as copper or copper alloy on the surface of the untreated electrolytic copper foil is preferable.
- a roughening method by plating generally used for copper foil for printed circuits disclosed in Patent Document 7 is preferably used. That is, after forming a granular copper plating layer by so-called “bake plating”, “cover plating” is performed on this granular copper plating layer so as not to impair the uneven shape, thereby substantially smoothing.
- a method by physical etching or chemical etching is suitable.
- physical etching there is a method of etching by sandblasting or the like, and for chemical etching, many liquids containing an inorganic or organic acid, an oxidizing agent, and an additive have been proposed.
- Patent Literature 8 discloses a corrosion inhibitor such as an inorganic acid + hydrogen peroxide + triazole + a surfactant.
- Patent Document 9 discloses a liquid containing inorganic acid + peroxide + azole + halide.
- (111) ⁇ 3 so that the average number of intersections between an arbitrary line segment having a length of 500 nm in a TEM image and a twin plane that is a (111) ⁇ 3 grain boundary is 5 to 40.
- an electrolytic copper foil with improved tensile strength and electrical conductivity can be obtained.
- durability is improved, battery capacity is increased, and charging / discharging is performed.
- a lithium ion secondary battery with improved characteristics can be manufactured.
- the observation of the metal structure when obtaining the number of intersections between an arbitrary line segment having a length of 500 nm in the TEM image and the twin plane which is the (111) ⁇ 3 grain boundary is performed by a transmission electron microscope (TEM). It carried out in.
- a TEM image is shown in FIG.
- the number of intersections with the (111) ⁇ 3 grain boundary is an arbitrary line segment having a length of 500 nm on the structure to be observed, and the twin plane that is the (111) ⁇ 3 grain boundary. Find the number of intersections with.
- the average crystal grain size can be measured by, for example, an intercept method. In the intercept method, an arbitrary line segment is drawn on the structure to be observed, and the average crystal grain size is obtained from the length of the line segment and the number of crystal grains intersecting with the line segment.
- the tensile strength is a value measured by a method defined in the IPC standard (IPC-TM-650).
- the conductivity is calculated from the specific resistance obtained based on the IPC standard (IPC-TM-650).
- Comparative Examples 1 to 3 an untreated copper foil having a thickness of 20 ⁇ m was produced from an electrolytic solution having the composition shown in Table 1.
- 2M-5S is 2-mercapto-5-benzimidazolesulfonic acid
- SPS is bis (3-sulfopropyl) disulfide
- DDAC diallyldimethylammonium chloride.
- the presence or absence of the (111) ⁇ 3 grain boundary and the number of intersections were determined by observing the metal structure with a transmission electron microscope with an observation field of 100 to 360,000 times.
- the (111) ⁇ 3 grain boundary was defined as a continuous and linear line of 10 nm or more in the metal structure observation.
- the “number of intersection points” is an arbitrary line segment having a length of 500 nm on the structure to be observed, and the number of intersection points with the twin plane which is the (111) ⁇ 3 grain boundary.
- a similar line is drawn while rotating by 60 ° around the midpoint of the line segment, the number of intersections between each line segment and the twin plane is obtained, and the twin plane intersecting each line is determined. The number of intersections was averaged to obtain the “number of intersections”.
- the conductivity is a value calculated from the specific resistance obtained based on the IPC standard (IPC-TM-650). In the comprehensive evaluation, “Good” indicates that both the tensile strength and the electrical conductivity are good, “Fair” indicates that the tensile strength and electrical conductivity are good, and “Poor” indicates that one of them is defective.
- Examples 1 to 11 in which the average number of intersection points between an arbitrary line segment having a length of 500 nm in a TEM image and a twin plane which is a (111) ⁇ 3 grain boundary are 5 to 40 are as follows: Both tensile strength and electrical conductivity were good. On the other hand, in Comparative Examples 1 to 3, either the tensile strength or the conductivity was poor.
- the electrolytic copper foil of the present invention can be preferably used for applications other than lithium ion secondary batteries, for example, as a copper foil for circuit boards and electronic device materials.
Abstract
An electrolytic copper foil having increased tensile strength and electrical conductivity is provided, as is a manufacturing method therefor. A lithium-ion secondary battery using a negative electrode that uses the aforementioned electrolytic copper foil as a collector is also provided. In a transmission electron microscopy (TEM) image of this electrolytic copper foil, the mean number of intersections between an arbitrary line segment 500 nm long and twin planes that are (111) Σ3 grain boundaries is between 5 and 40, inclusive. The aforementioned lithium-ion secondary battery uses a negative electrode that uses said electrolytic copper foil as a collector.
Description
本発明は、高強度かつ高導電性を有する電解銅箔とその製造方法、該電解銅箔を用いた負極電極、該負極電極を組み込んだリチウムイオン二次電池に関する。
The present invention relates to an electrolytic copper foil having high strength and high conductivity, a method for producing the same, a negative electrode using the electrolytic copper foil, and a lithium ion secondary battery incorporating the negative electrode.
リチウム（Ｌｉ）イオン二次電池は、例えば、正極と、負極集電体の表面に負極活物質層が形成された負極と、非水電解質とで構成されており、携帯電話やノートタイプパソコン等に使用されている。
リチウムイオン二次電池の負極は、例えば、両面が平滑な銅箔からなる負極集電体の表面に、負極活物質層としてカーボン粒子を塗布、乾燥し、さらにプレスして形成されている。
上記の銅箔からなる負極集電体としては、電解により製造された、いわゆる「未処理電解銅箔」に防錆処理を施したものが使用されている。 A lithium (Li) ion secondary battery includes, for example, a positive electrode, a negative electrode having a negative electrode active material layer formed on the surface of a negative electrode current collector, and a non-aqueous electrolyte. Is used.
The negative electrode of the lithium ion secondary battery is formed, for example, by applying carbon particles as a negative electrode active material layer on the surface of a negative electrode current collector made of a copper foil having smooth surfaces, drying, and pressing.
As the negative electrode current collector made of the above copper foil, a so-called “untreated electrolytic copper foil” manufactured by electrolysis is subjected to a rust prevention treatment.
リチウムイオン二次電池の負極は、例えば、両面が平滑な銅箔からなる負極集電体の表面に、負極活物質層としてカーボン粒子を塗布、乾燥し、さらにプレスして形成されている。
上記の銅箔からなる負極集電体としては、電解により製造された、いわゆる「未処理電解銅箔」に防錆処理を施したものが使用されている。 A lithium (Li) ion secondary battery includes, for example, a positive electrode, a negative electrode having a negative electrode active material layer formed on the surface of a negative electrode current collector, and a non-aqueous electrolyte. Is used.
The negative electrode of the lithium ion secondary battery is formed, for example, by applying carbon particles as a negative electrode active material layer on the surface of a negative electrode current collector made of a copper foil having smooth surfaces, drying, and pressing.
As the negative electrode current collector made of the above copper foil, a so-called “untreated electrolytic copper foil” manufactured by electrolysis is subjected to a rust prevention treatment.
リチウムイオン二次電池の負極活物質としては、炭素材料の理論容量を大きく超える充放電容量を持つ次世代の負極活物質の開発が進められている。
例えば、シリコン（Ｓｉ）や錫（Ｓｎ）などのリチウムと合金化可能な金属を含む材料が期待されている。 As a negative electrode active material for a lithium ion secondary battery, development of a next-generation negative electrode active material having a charge / discharge capacity that greatly exceeds the theoretical capacity of a carbon material is underway.
For example, a material containing a metal that can be alloyed with lithium such as silicon (Si) or tin (Sn) is expected.
例えば、シリコン（Ｓｉ）や錫（Ｓｎ）などのリチウムと合金化可能な金属を含む材料が期待されている。 As a negative electrode active material for a lithium ion secondary battery, development of a next-generation negative electrode active material having a charge / discharge capacity that greatly exceeds the theoretical capacity of a carbon material is underway.
For example, a material containing a metal that can be alloyed with lithium such as silicon (Si) or tin (Sn) is expected.
特許文献１～１１には、リチウムイオン二次電池負極集電体などに用いられる電解銅箔についての記載がある。
Patent Documents 1 to 11 describe an electrolytic copper foil used for a negative electrode current collector of a lithium ion secondary battery.
しかしながら、負極活物質として開発が進められているリチウムと合金化可能なシリコンをはじめとする材料は、充放電時のリチウムの吸蔵及び放出に伴う体積変化が大きく、集電体と活物質との接着状態を良好に維持することが困難となり、集電体に破壊が起こる場合がある等、サイクル特性が劣化してしまう問題があった。
この問題を解決する対策として、集電体の引張強度を、あるいは伸びを所定値以上とすることとが考えられる。この集電体の引張強度や伸びを所定値以上とする対策としては、集電体を構成する箔の結晶粒の微細化や、他元素との合金化による高強度化が考えられるが、このような対策は電池や電子デバイスとして用いる際に必要とされる導電性が低下してしまうという問題がある。
上記課題を解決するために本発明は、高強度かつ高導電性を有する電解銅箔を提供することを目的とする。
また本発明は高強度（引張強度）かつ高導電性を有する本発明電解銅箔を集電体とする負極電極、該負極電極を組み込んだリチウムイオン二次電池を提供することを目的とする。
なお、本発明の電解銅箔は、電池用集電体以外の用途として、たとえば、回路基板用銅箔としても、好ましく使用することができる。 However, materials such as silicon that can be alloyed with lithium, which are being developed as negative electrode active materials, have a large volume change due to insertion and extraction of lithium during charge and discharge, and the current collector and active material There is a problem that the cycle characteristics are deteriorated such that it is difficult to maintain a good adhesion state and the current collector may be broken.
As a measure for solving this problem, it is considered that the tensile strength of the current collector or the elongation is set to a predetermined value or more. As measures to increase the tensile strength and elongation of the current collector to a predetermined value or more, it is possible to refine the crystal grains of the foil constituting the current collector or increase the strength by alloying with other elements. Such measures have a problem that the conductivity required when used as a battery or an electronic device is lowered.
In order to solve the above problems, an object of the present invention is to provide an electrolytic copper foil having high strength and high conductivity.
Another object of the present invention is to provide a negative electrode using the electrolytic copper foil of the present invention having high strength (tensile strength) and high conductivity as a current collector, and a lithium ion secondary battery incorporating the negative electrode.
In addition, the electrolytic copper foil of this invention can be preferably used also as a copper foil for circuit boards as uses other than the collector for batteries, for example.
この問題を解決する対策として、集電体の引張強度を、あるいは伸びを所定値以上とすることとが考えられる。この集電体の引張強度や伸びを所定値以上とする対策としては、集電体を構成する箔の結晶粒の微細化や、他元素との合金化による高強度化が考えられるが、このような対策は電池や電子デバイスとして用いる際に必要とされる導電性が低下してしまうという問題がある。
上記課題を解決するために本発明は、高強度かつ高導電性を有する電解銅箔を提供することを目的とする。
また本発明は高強度（引張強度）かつ高導電性を有する本発明電解銅箔を集電体とする負極電極、該負極電極を組み込んだリチウムイオン二次電池を提供することを目的とする。
なお、本発明の電解銅箔は、電池用集電体以外の用途として、たとえば、回路基板用銅箔としても、好ましく使用することができる。 However, materials such as silicon that can be alloyed with lithium, which are being developed as negative electrode active materials, have a large volume change due to insertion and extraction of lithium during charge and discharge, and the current collector and active material There is a problem that the cycle characteristics are deteriorated such that it is difficult to maintain a good adhesion state and the current collector may be broken.
As a measure for solving this problem, it is considered that the tensile strength of the current collector or the elongation is set to a predetermined value or more. As measures to increase the tensile strength and elongation of the current collector to a predetermined value or more, it is possible to refine the crystal grains of the foil constituting the current collector or increase the strength by alloying with other elements. Such measures have a problem that the conductivity required when used as a battery or an electronic device is lowered.
In order to solve the above problems, an object of the present invention is to provide an electrolytic copper foil having high strength and high conductivity.
Another object of the present invention is to provide a negative electrode using the electrolytic copper foil of the present invention having high strength (tensile strength) and high conductivity as a current collector, and a lithium ion secondary battery incorporating the negative electrode.
In addition, the electrolytic copper foil of this invention can be preferably used also as a copper foil for circuit boards as uses other than the collector for batteries, for example.
本発明の電解銅箔は、透過電子顕微鏡（ＴＥＭ）観察像において、５００ｎｍの長さの任意の線分と（１１１）Σ３粒界である双晶面との交点の平均の数が５～４０である。
The electrolytic copper foil of the present invention has an average number of intersection points of an arbitrary line segment having a length of 500 nm and a twin plane which is a (111) Σ3 grain boundary in a transmission electron microscope (TEM) observation image. It is.
上記の本発明の電解銅箔は、透過電子顕微鏡（ＴＥＭ）観察像において、５００ｎｍの長さの任意の線分と（１１１）Σ３粒界である双晶面との交点の平均の数がより好ましくは１０～３６である。
In the electrolytic copper foil of the present invention described above, the average number of intersections between an arbitrary line segment having a length of 500 nm and a twin plane which is a (111) Σ3 grain boundary in a transmission electron microscope (TEM) observation image is larger. A preferred range is 10 to 36.
また、本発明の電解銅箔の製造方法は、銅及び硫酸を含み、添加剤として塩素を２０～５０ｐｐｍ、チオ尿素系化合物を１～１０ｐｐｍ、水溶性高分子系化合物を１～２０ｐｐｍ含有する電解めっき液で電解処理を行い、透過電子顕微鏡（ＴＥＭ）観察像において、５００ｎｍの長さの任意の線分と（１１１）Σ３粒界である双晶面との交点の平均の数が５～４０、より好ましくは１０～３６である電解銅箔を製造する、電解銅箔の製造方法である。
The method for producing an electrolytic copper foil of the present invention includes an electrolytic solution containing copper and sulfuric acid, containing 20 to 50 ppm of chlorine, 1 to 10 ppm of a thiourea compound, and 1 to 20 ppm of a water-soluble polymer compound as additives. The average number of intersections between an arbitrary line segment having a length of 500 nm and a twin plane which is a (111) Σ3 grain boundary is 5 to 40 in a transmission electron microscope (TEM) observation image after electrolytic treatment with a plating solution. More preferably, the electrolytic copper foil production method is for producing an electrolytic copper foil of 10 to 36.
本発明によれば、引張強度と導電率を高めた電解銅箔を提供できる。
また、引張強度と導電率を高めた本発明電解銅箔を集電体とすることで、二次電池の電池容量の増加及び充放電特性を高めたリチウムイオン二次電池を提供することができる。 ADVANTAGE OF THE INVENTION According to this invention, the electrolytic copper foil which raised tensile strength and electrical conductivity can be provided.
In addition, by using the electrolytic copper foil of the present invention with increased tensile strength and conductivity as a current collector, it is possible to provide a lithium ion secondary battery with increased battery capacity and improved charge / discharge characteristics of the secondary battery. .
また、引張強度と導電率を高めた本発明電解銅箔を集電体とすることで、二次電池の電池容量の増加及び充放電特性を高めたリチウムイオン二次電池を提供することができる。 ADVANTAGE OF THE INVENTION According to this invention, the electrolytic copper foil which raised tensile strength and electrical conductivity can be provided.
In addition, by using the electrolytic copper foil of the present invention with increased tensile strength and conductivity as a current collector, it is possible to provide a lithium ion secondary battery with increased battery capacity and improved charge / discharge characteristics of the secondary battery. .
［高強度、高導電率電解銅箔の構成］
本実施形態の電解銅箔は、リチウムイオン二次電池の負極集電体として好適な銅箔であり、断面の結晶構造、即ち、透過電子顕微鏡（ＴＥＭ）での観察像{以下単に「ＴＥＭ画像」と表現することがある｝において、５００ｎｍの長さの任意の線分と（１１１）Σ３粒界である双晶面との交点の平均の数が５～４０、より好ましくは１０～３６である。
なお、本明細書において、「５００ｎｍの長さの任意の線分と（１１１）Σ３粒界である双晶面との交点の平均の数」とは、図２に示すようにＴＥＭ画像に先ず５００ｎｍの長さの任意の線分を記入し、（１１１）Σ３粒界である双晶面との交点の数を求める。次いで前記線分の中点を中心に６０°ずつ回転させながら同様の線を３本引き、それぞれの線分と双晶面の交点の数を求め、３本の各線と交差する双晶面との交点の数を平均して求めた値である。 [Configuration of high strength, high conductivity electrolytic copper foil]
The electrolytic copper foil of the present embodiment is a copper foil suitable as a negative electrode current collector of a lithium ion secondary battery. The crystal structure of the cross section, that is, an observation image with a transmission electron microscope (TEM) {hereinafter simply referred to as “TEM image”. The average number of intersections between an arbitrary line segment having a length of 500 nm and a twin plane that is a (111) Σ3 grain boundary is 5 to 40, more preferably 10 to 36. is there.
In the present specification, “the average number of intersections between an arbitrary line segment having a length of 500 nm and a twin plane which is a (111) Σ3 grain boundary” is first shown in a TEM image as shown in FIG. An arbitrary line segment having a length of 500 nm is entered, and the number of intersections with the twin plane which is the (111) Σ3 grain boundary is obtained. Next, three similar lines are drawn while rotating by 60 ° around the midpoint of the line segment, and the number of intersections between each line segment and the twin plane is obtained. This is a value obtained by averaging the number of intersections.
本実施形態の電解銅箔は、リチウムイオン二次電池の負極集電体として好適な銅箔であり、断面の結晶構造、即ち、透過電子顕微鏡（ＴＥＭ）での観察像{以下単に「ＴＥＭ画像」と表現することがある｝において、５００ｎｍの長さの任意の線分と（１１１）Σ３粒界である双晶面との交点の平均の数が５～４０、より好ましくは１０～３６である。
なお、本明細書において、「５００ｎｍの長さの任意の線分と（１１１）Σ３粒界である双晶面との交点の平均の数」とは、図２に示すようにＴＥＭ画像に先ず５００ｎｍの長さの任意の線分を記入し、（１１１）Σ３粒界である双晶面との交点の数を求める。次いで前記線分の中点を中心に６０°ずつ回転させながら同様の線を３本引き、それぞれの線分と双晶面の交点の数を求め、３本の各線と交差する双晶面との交点の数を平均して求めた値である。 [Configuration of high strength, high conductivity electrolytic copper foil]
The electrolytic copper foil of the present embodiment is a copper foil suitable as a negative electrode current collector of a lithium ion secondary battery. The crystal structure of the cross section, that is, an observation image with a transmission electron microscope (TEM) {hereinafter simply referred to as “TEM image”. The average number of intersections between an arbitrary line segment having a length of 500 nm and a twin plane that is a (111) Σ3 grain boundary is 5 to 40, more preferably 10 to 36. is there.
In the present specification, “the average number of intersections between an arbitrary line segment having a length of 500 nm and a twin plane which is a (111) Σ3 grain boundary” is first shown in a TEM image as shown in FIG. An arbitrary line segment having a length of 500 nm is entered, and the number of intersections with the twin plane which is the (111) Σ3 grain boundary is obtained. Next, three similar lines are drawn while rotating by 60 ° around the midpoint of the line segment, and the number of intersections between each line segment and the twin plane is obtained. This is a value obtained by averaging the number of intersections.
ナノサイズの結晶粒を多く持つ金属組織に（１１１）Σ３粒界を数多く導入し、５００ｎｍの長さの任意の線分と（１１１）Σ３粒界である双晶面との交点の平均の数が５～４０とすることで、機械強度の代表的指標である引張強度を向上させつつ、二次電池用として使用するのに適切な導電率に設定することができる。
A large number of (111) Σ3 grain boundaries are introduced into a metal structure having many nano-sized crystal grains, and the average number of intersections between an arbitrary line segment having a length of 500 nm and a twin plane that is a (111) Σ3 grain boundary By setting the ratio to 5 to 40, it is possible to set the conductivity suitable for use for a secondary battery while improving the tensile strength, which is a typical index of mechanical strength.
例えば、本実施形態の電解銅箔は、電解銅箔を構成する銅粒子の平均粒径が５～２００ｎｍであることが好ましい。
平均粒径が５ｎｍ未満の場合は、導電率が低くなるため、好ましくない。また、２００ｎｍを超えると、引張強度が低下するため、好ましくない。 For example, in the electrolytic copper foil of the present embodiment, it is preferable that the average particle diameter of the copper particles constituting the electrolytic copper foil is 5 to 200 nm.
An average particle size of less than 5 nm is not preferable because the conductivity is low. On the other hand, if it exceeds 200 nm, the tensile strength decreases, which is not preferable.
平均粒径が５ｎｍ未満の場合は、導電率が低くなるため、好ましくない。また、２００ｎｍを超えると、引張強度が低下するため、好ましくない。 For example, in the electrolytic copper foil of the present embodiment, it is preferable that the average particle diameter of the copper particles constituting the electrolytic copper foil is 5 to 200 nm.
An average particle size of less than 5 nm is not preferable because the conductivity is low. On the other hand, if it exceeds 200 nm, the tensile strength decreases, which is not preferable.
また、例えば、本実施形態の電解銅箔は、引張強度が好ましくは５００～９００ＭＰａである。
引張強度が５００～９００ＭＰａであれば、薄膜化された場合でも十分に電池用構造部材およびその他電子デバイス材料として好ましく使用することが可能となる。
引張強度が５００ＭＰａを下回ると、構造部材として強度が不十分であり、９００ＭＰａを超えると加工時に割れなどの欠陥が生じやすい。
また、本実施形態の電解銅箔は、引張強度がより好ましくは６００～８００ＭＰａである。６００～８００ＭＰａであると、耐久性がさらに高められ、電池容量をさらに増加できる。 For example, the electrolytic copper foil of the present embodiment preferably has a tensile strength of 500 to 900 MPa.
When the tensile strength is 500 to 900 MPa, it can be preferably used as a battery structural member and other electronic device material even when it is thinned.
When the tensile strength is less than 500 MPa, the strength of the structural member is insufficient, and when it exceeds 900 MPa, defects such as cracks are likely to occur during processing.
In addition, the electrolytic copper foil of the present embodiment has a tensile strength of more preferably 600 to 800 MPa. When the pressure is 600 to 800 MPa, the durability is further enhanced and the battery capacity can be further increased.
引張強度が５００～９００ＭＰａであれば、薄膜化された場合でも十分に電池用構造部材およびその他電子デバイス材料として好ましく使用することが可能となる。
引張強度が５００ＭＰａを下回ると、構造部材として強度が不十分であり、９００ＭＰａを超えると加工時に割れなどの欠陥が生じやすい。
また、本実施形態の電解銅箔は、引張強度がより好ましくは６００～８００ＭＰａである。６００～８００ＭＰａであると、耐久性がさらに高められ、電池容量をさらに増加できる。 For example, the electrolytic copper foil of the present embodiment preferably has a tensile strength of 500 to 900 MPa.
When the tensile strength is 500 to 900 MPa, it can be preferably used as a battery structural member and other electronic device material even when it is thinned.
When the tensile strength is less than 500 MPa, the strength of the structural member is insufficient, and when it exceeds 900 MPa, defects such as cracks are likely to occur during processing.
In addition, the electrolytic copper foil of the present embodiment has a tensile strength of more preferably 600 to 800 MPa. When the pressure is 600 to 800 MPa, the durability is further enhanced and the battery capacity can be further increased.
本実施形態の電解銅箔は、導電率は好ましくは６０％ＩＡＣＳ以上である。
導電率を６０％ＩＡＣＳ以上にすることで、十分な導電性を有しながら、電子デバイスとして使用される際に発生する熱を抑えることが可能となる。
導電率が６０％ＩＡＣＳ以下の場合は、電気抵抗による発熱が生じ、あるいは、リチウムイオン二次電池用集電体として用いられる際には、ＩＲ降下により出力電圧が低下するなどの問題が生じる。
また、本実施形態の電解銅箔は、導電率がより好ましくは７０％ＩＡＣＳ以上である。７０％ＩＡＣＳ以上であると、リチウムイオン二次電池として使用される際に充放電特性がさらに高められる。 The electrolytic copper foil of this embodiment preferably has a conductivity of 60% IACS or higher.
By setting the conductivity to 60% IACS or more, it is possible to suppress heat generated when used as an electronic device while having sufficient conductivity.
When the electrical conductivity is 60% IACS or less, heat is generated due to electric resistance, or when used as a current collector for a lithium ion secondary battery, problems such as a decrease in output voltage due to IR drop occur.
In addition, the electrolytic copper foil of the present embodiment has a conductivity of 70% IACS or more more preferably. When it is at least 70% IACS, the charge / discharge characteristics are further enhanced when used as a lithium ion secondary battery.
導電率を６０％ＩＡＣＳ以上にすることで、十分な導電性を有しながら、電子デバイスとして使用される際に発生する熱を抑えることが可能となる。
導電率が６０％ＩＡＣＳ以下の場合は、電気抵抗による発熱が生じ、あるいは、リチウムイオン二次電池用集電体として用いられる際には、ＩＲ降下により出力電圧が低下するなどの問題が生じる。
また、本実施形態の電解銅箔は、導電率がより好ましくは７０％ＩＡＣＳ以上である。７０％ＩＡＣＳ以上であると、リチウムイオン二次電池として使用される際に充放電特性がさらに高められる。 The electrolytic copper foil of this embodiment preferably has a conductivity of 60% IACS or higher.
By setting the conductivity to 60% IACS or more, it is possible to suppress heat generated when used as an electronic device while having sufficient conductivity.
When the electrical conductivity is 60% IACS or less, heat is generated due to electric resistance, or when used as a current collector for a lithium ion secondary battery, problems such as a decrease in output voltage due to IR drop occur.
In addition, the electrolytic copper foil of the present embodiment has a conductivity of 70% IACS or more more preferably. When it is at least 70% IACS, the charge / discharge characteristics are further enhanced when used as a lithium ion secondary battery.
上記のように、ＴＥＭ画像における、５００ｎｍの長さの任意の線分と（１１１）Σ３粒界である双晶面との交点の平均の数が５～４０とすることで、上記の好ましい引張強度と、適切な導電率を実現できる。
As described above, in the TEM image, the average number of intersections between an arbitrary line segment having a length of 500 nm and a twin plane which is a (111) Σ3 grain boundary is 5 to 40, so that the above preferable tensile Strength and appropriate electrical conductivity can be realized.
また、本実施形態の高強度高導電率電解銅箔は、表面に防錆処理層が設けられている。
防錆処理層は、例えば、クロメート処理層、あるいは、Ｎｉ又はＮｉ合金めっき層、Ｃｏ又はＣｏ合金めっき層、Ｚｎ又はＺｎ合金めっき層、Ｓｎ又はＳｎ合金めっき層、或いは上記各種めっき層上にさらにクロメート処理層を設けたもの等の無機防錆処理、あるいは、ベンゾトリアゾール等の有機防錆処理層である。
さらに、シランカップリング剤処理層等が形成されていてもよい。
上記無機防錆処理、有機防錆処理、シランカップリング剤処理は、リチウムイオン二次電池として使用される際に活物質との密着強度を高め、電池の充放電サイクル効率の低下を防ぐ役割も果たす。 Moreover, the high intensity | strength high electrical conductivity electrolytic copper foil of this embodiment is provided with the antirust process layer on the surface.
The antirust treatment layer is, for example, a chromate treatment layer, or a Ni or Ni alloy plating layer, a Co or Co alloy plating layer, a Zn or Zn alloy plating layer, a Sn or Sn alloy plating layer, or the above various plating layers. It is an inorganic rust prevention treatment such as one provided with a chromate treatment layer, or an organic rust prevention treatment layer such as benzotriazole.
Furthermore, a silane coupling agent treatment layer or the like may be formed.
The inorganic rust prevention treatment, organic rust prevention treatment, and silane coupling agent treatment increase the adhesion strength with the active material when used as a lithium ion secondary battery, and also prevent the charge / discharge cycle efficiency of the battery from decreasing. Fulfill.
防錆処理層は、例えば、クロメート処理層、あるいは、Ｎｉ又はＮｉ合金めっき層、Ｃｏ又はＣｏ合金めっき層、Ｚｎ又はＺｎ合金めっき層、Ｓｎ又はＳｎ合金めっき層、或いは上記各種めっき層上にさらにクロメート処理層を設けたもの等の無機防錆処理、あるいは、ベンゾトリアゾール等の有機防錆処理層である。
さらに、シランカップリング剤処理層等が形成されていてもよい。
上記無機防錆処理、有機防錆処理、シランカップリング剤処理は、リチウムイオン二次電池として使用される際に活物質との密着強度を高め、電池の充放電サイクル効率の低下を防ぐ役割も果たす。 Moreover, the high intensity | strength high electrical conductivity electrolytic copper foil of this embodiment is provided with the antirust process layer on the surface.
The antirust treatment layer is, for example, a chromate treatment layer, or a Ni or Ni alloy plating layer, a Co or Co alloy plating layer, a Zn or Zn alloy plating layer, a Sn or Sn alloy plating layer, or the above various plating layers. It is an inorganic rust prevention treatment such as one provided with a chromate treatment layer, or an organic rust prevention treatment layer such as benzotriazole.
Furthermore, a silane coupling agent treatment layer or the like may be formed.
The inorganic rust prevention treatment, organic rust prevention treatment, and silane coupling agent treatment increase the adhesion strength with the active material when used as a lithium ion secondary battery, and also prevent the charge / discharge cycle efficiency of the battery from decreasing. Fulfill.
また、本実施形態の高強度高導電率電解銅箔は、該電解銅箔の活物質層を設ける表面に粗化処理が施され、当該粗化処理が施された表面に防錆処理層が設けられている。
In addition, the high-strength, high-conductivity electrolytic copper foil of the present embodiment is subjected to a roughening treatment on the surface on which the active material layer of the electrolytic copper foil is provided, and a rust-proofing treatment layer is provided on the surface subjected to the roughening treatment. Is provided.
［高強度高導電率電解銅箔の製造方法］
本実施形態の電解銅箔は、例えば、硫酸－硫酸銅水溶液を電解液とし、白金属元素又はその酸化物元素で被覆したチタンからなる不溶性陽極と該陽極に対向させて設けられたチタン製陰極ドラムとの間に該電解液を供給し、陰極ドラムを一定速度で回転させながら、両極間に直流電流を通電することにより陰極ドラム表面上に銅を析出させ、析出した銅を陰極ドラム表面から引き剥がし、連続的に巻き取る方法により製造される。 [Method for producing high-strength, high-conductivity electrolytic copper foil]
The electrolytic copper foil of the present embodiment is, for example, an insoluble anode made of titanium coated with a white metal element or an oxide element thereof using a sulfuric acid-copper sulfate aqueous solution as an electrolytic solution, and a titanium cathode provided facing the anode. While supplying the electrolytic solution between the drum and rotating the cathode drum at a constant speed, a direct current is passed between the two electrodes to deposit copper on the surface of the cathode drum, and the deposited copper is removed from the surface of the cathode drum. It is manufactured by a method of peeling and continuously winding.
本実施形態の電解銅箔は、例えば、硫酸－硫酸銅水溶液を電解液とし、白金属元素又はその酸化物元素で被覆したチタンからなる不溶性陽極と該陽極に対向させて設けられたチタン製陰極ドラムとの間に該電解液を供給し、陰極ドラムを一定速度で回転させながら、両極間に直流電流を通電することにより陰極ドラム表面上に銅を析出させ、析出した銅を陰極ドラム表面から引き剥がし、連続的に巻き取る方法により製造される。 [Method for producing high-strength, high-conductivity electrolytic copper foil]
The electrolytic copper foil of the present embodiment is, for example, an insoluble anode made of titanium coated with a white metal element or an oxide element thereof using a sulfuric acid-copper sulfate aqueous solution as an electrolytic solution, and a titanium cathode provided facing the anode. While supplying the electrolytic solution between the drum and rotating the cathode drum at a constant speed, a direct current is passed between the two electrodes to deposit copper on the surface of the cathode drum, and the deposited copper is removed from the surface of the cathode drum. It is manufactured by a method of peeling and continuously winding.
本実施形態の電解銅箔は、例えば、硫酸－硫酸銅電解めっき液において電解処理を行って製造することができる。
電解処理時の電流密度は、３０～７０Ａ／ｄｍ２とすることが好ましい。
硫酸－硫酸銅電解めっき液の銅濃度としては、例えば、４０～１２０ｇ／Ｌの範囲を用い、好ましくは６０～１００ｇ／Ｌの範囲を用いる。
また、硫酸－硫酸銅電解めっき液の硫酸濃度としては、例えば、４０～６０ｇ／Ｌの範囲を用いる。この硫酸濃度は重要な条件であり、この範囲よりも不足するとめっき液の導電率が低くなるため銅箔の均一電着性が低下し、過剰であると以下に述べるＮ（窒素）及びＳ（硫黄）含有添加剤の効果が表れにくくなり、銅箔の強度低下や結晶配向性のランダム化が起こるため好ましくない。
硫酸－硫酸銅電解めっき液の塩素濃度としては、例えば、２０～５０ｐｐｍの範囲を用いる。また、以下に示す有機添加剤ＡとＢの両方を用いる。 The electrolytic copper foil of the present embodiment can be produced, for example, by performing electrolytic treatment in a sulfuric acid-copper sulfate electrolytic plating solution.
The current density during the electrolytic treatment is preferably 30 to 70 A / dm 2 .
The copper concentration of the sulfuric acid-copper sulfate electroplating solution is, for example, in the range of 40 to 120 g / L, and preferably in the range of 60 to 100 g / L.
The sulfuric acid concentration in the sulfuric acid-copper sulfate electroplating solution is, for example, in the range of 40 to 60 g / L. This sulfuric acid concentration is an important condition, and if it is less than this range, the conductivity of the plating solution will be lowered, so that the uniform electrodeposition of the copper foil will be reduced, and N (nitrogen) and S ( This is not preferable because the effect of the sulfur-containing additive is hardly exhibited, and the strength of the copper foil is reduced and the crystal orientation is randomized.
As the chlorine concentration of the sulfuric acid-copper sulfate electroplating solution, for example, a range of 20 to 50 ppm is used. Moreover, both the organic additives A and B shown below are used.
電解処理時の電流密度は、３０～７０Ａ／ｄｍ２とすることが好ましい。
硫酸－硫酸銅電解めっき液の銅濃度としては、例えば、４０～１２０ｇ／Ｌの範囲を用い、好ましくは６０～１００ｇ／Ｌの範囲を用いる。
また、硫酸－硫酸銅電解めっき液の硫酸濃度としては、例えば、４０～６０ｇ／Ｌの範囲を用いる。この硫酸濃度は重要な条件であり、この範囲よりも不足するとめっき液の導電率が低くなるため銅箔の均一電着性が低下し、過剰であると以下に述べるＮ（窒素）及びＳ（硫黄）含有添加剤の効果が表れにくくなり、銅箔の強度低下や結晶配向性のランダム化が起こるため好ましくない。
硫酸－硫酸銅電解めっき液の塩素濃度としては、例えば、２０～５０ｐｐｍの範囲を用いる。また、以下に示す有機添加剤ＡとＢの両方を用いる。 The electrolytic copper foil of the present embodiment can be produced, for example, by performing electrolytic treatment in a sulfuric acid-copper sulfate electrolytic plating solution.
The current density during the electrolytic treatment is preferably 30 to 70 A / dm 2 .
The copper concentration of the sulfuric acid-copper sulfate electroplating solution is, for example, in the range of 40 to 120 g / L, and preferably in the range of 60 to 100 g / L.
The sulfuric acid concentration in the sulfuric acid-copper sulfate electroplating solution is, for example, in the range of 40 to 60 g / L. This sulfuric acid concentration is an important condition, and if it is less than this range, the conductivity of the plating solution will be lowered, so that the uniform electrodeposition of the copper foil will be reduced, and N (nitrogen) and S ( This is not preferable because the effect of the sulfur-containing additive is hardly exhibited, and the strength of the copper foil is reduced and the crystal orientation is randomized.
As the chlorine concentration of the sulfuric acid-copper sulfate electroplating solution, for example, a range of 20 to 50 ppm is used. Moreover, both the organic additives A and B shown below are used.
有機添加剤Ａは、Ｎ（窒素）原子およびＳ（硫黄）原子を１分子中に少なくとも１つずつ以上含む有機化合物である。有機添加剤Ａを少なくとも１種類適量に加えることで、製造される電解銅箔の金属組織に（１１１）Σ３粒界を数多く導入することができる。
有機添加剤Ａは、望ましくはチオ尿素系化合物であり、更に望ましくは炭素数が３以上のチオ尿素系化合物である。
有機添加剤Ａとして、例えば、チオ尿素（ＣＨ4Ｎ2Ｓ）、Ｎ，Ｎ’－ジメチルチオ尿素（Ｃ3Ｈ8Ｎ2Ｓ）、Ｎ，Ｎ’－ジエチルチオ尿素（Ｃ5Ｈ12Ｎ2Ｓ）、テトラメチルチオ尿素（Ｃ5Ｈ12Ｎ2Ｓ）、チオセミカルバシド（ＣＨ5Ｎ3Ｓ）、Ｎ－アリルチオ尿素（Ｃ4Ｈ8Ｎ2Ｓ）、エチレンチオ尿素（Ｃ3Ｈ6Ｎ2Ｓ）等の水溶性のチオ尿素、またはチオ尿素誘導体などのチオ尿素系化合物である。電解めっき液に添加する添加剤Ａとしては、これらチオ尿素系化合物から選ばれた一種以上を用いる。 The organic additive A is an organic compound containing at least one N (nitrogen) atom and S (sulfur) atom in one molecule. By adding an appropriate amount of at least one organic additive A, a large number of (111) Σ3 grain boundaries can be introduced into the metal structure of the produced electrolytic copper foil.
The organic additive A is desirably a thiourea compound, and more desirably a thiourea compound having 3 or more carbon atoms.
Examples of the organic additive A include thiourea (CH 4 N 2 S), N, N′-dimethylthiourea (C 3 H 8 N 2 S), N, N′-diethylthiourea (C 5 H 12 N 2 S). ), tetramethyl thiourea (C 5 H 12 N 2 S ), thiosemicarbazide Sid (CH 5 N 3 S), N- allyl thiourea (C 4 H 8 N 2 S ), ethylene thiourea (C 3 H 6 N 2 S) is a water-soluble thiourea or a thiourea compound such as a thiourea derivative. As the additive A added to the electrolytic plating solution, one or more selected from these thiourea compounds are used.
有機添加剤Ａは、望ましくはチオ尿素系化合物であり、更に望ましくは炭素数が３以上のチオ尿素系化合物である。
有機添加剤Ａとして、例えば、チオ尿素（ＣＨ4Ｎ2Ｓ）、Ｎ，Ｎ’－ジメチルチオ尿素（Ｃ3Ｈ8Ｎ2Ｓ）、Ｎ，Ｎ’－ジエチルチオ尿素（Ｃ5Ｈ12Ｎ2Ｓ）、テトラメチルチオ尿素（Ｃ5Ｈ12Ｎ2Ｓ）、チオセミカルバシド（ＣＨ5Ｎ3Ｓ）、Ｎ－アリルチオ尿素（Ｃ4Ｈ8Ｎ2Ｓ）、エチレンチオ尿素（Ｃ3Ｈ6Ｎ2Ｓ）等の水溶性のチオ尿素、またはチオ尿素誘導体などのチオ尿素系化合物である。電解めっき液に添加する添加剤Ａとしては、これらチオ尿素系化合物から選ばれた一種以上を用いる。 The organic additive A is an organic compound containing at least one N (nitrogen) atom and S (sulfur) atom in one molecule. By adding an appropriate amount of at least one organic additive A, a large number of (111) Σ3 grain boundaries can be introduced into the metal structure of the produced electrolytic copper foil.
The organic additive A is desirably a thiourea compound, and more desirably a thiourea compound having 3 or more carbon atoms.
Examples of the organic additive A include thiourea (CH 4 N 2 S), N, N′-dimethylthiourea (C 3 H 8 N 2 S), N, N′-diethylthiourea (C 5 H 12 N 2 S). ), tetramethyl thiourea (C 5 H 12 N 2 S ), thiosemicarbazide Sid (CH 5 N 3 S), N- allyl thiourea (C 4 H 8 N 2 S ), ethylene thiourea (C 3 H 6 N 2 S) is a water-soluble thiourea or a thiourea compound such as a thiourea derivative. As the additive A added to the electrolytic plating solution, one or more selected from these thiourea compounds are used.
有機添加剤Ｂは、例えば、ニカワ、ゼラチン、ポリエチレングリコール、ポリプロピレングリコール、デンプン、セルロース系水溶性高分子（カルボキシルメチルセルロース、ヒドロキシエチルセルロース等）等の高分子多糖類、ポリエチレンイミン、ポリアミン系高分子、ポリアクリルアミドなどの水溶性高分子化合物等のである。電解めっき液に添加する添加剤Ｂとしては、これら水溶性高分子系化合物から選ばれた一種以上を用いる。
有機添加剤Ａに加えて有機添加剤Ｂをさらに追加することで、製造される電解銅箔の金属組織に（１１１）Σ３粒界を数多く導入することができる。 Organic additives B include, for example, glue, gelatin, polyethylene glycol, polypropylene glycol, starch, high molecular polysaccharides such as cellulose water-soluble polymers (carboxyl methyl cellulose, hydroxyethyl cellulose, etc.), polyethylene imine, polyamine polymers, poly Water-soluble polymer compounds such as acrylamide. As additive B to be added to the electroplating solution, one or more selected from these water-soluble polymer compounds are used.
By further adding organic additive B in addition to organic additive A, a large number of (111) Σ3 grain boundaries can be introduced into the metal structure of the produced electrolytic copper foil.
有機添加剤Ａに加えて有機添加剤Ｂをさらに追加することで、製造される電解銅箔の金属組織に（１１１）Σ３粒界を数多く導入することができる。 Organic additives B include, for example, glue, gelatin, polyethylene glycol, polypropylene glycol, starch, high molecular polysaccharides such as cellulose water-soluble polymers (carboxyl methyl cellulose, hydroxyethyl cellulose, etc.), polyethylene imine, polyamine polymers, poly Water-soluble polymer compounds such as acrylamide. As additive B to be added to the electroplating solution, one or more selected from these water-soluble polymer compounds are used.
By further adding organic additive B in addition to organic additive A, a large number of (111) Σ3 grain boundaries can be introduced into the metal structure of the produced electrolytic copper foil.
例えば、銅及び硫酸を含み、添加剤として塩素を２０～５０ｐｐｍ、チオ尿素系化合物を１～１０ｐｐｍ、水溶性高分子化合物を１～２０ｐｐｍ含有する電解めっき液で電解処理を行うことで、ＴＥＭ画像において、５００ｎｍの長さの任意の線分と（１１１）Σ３粒界である双晶面との交点の平均の数が５～４０である電解銅箔を製造することができる。
For example, a TEM image is obtained by performing electrolytic treatment with an electrolytic plating solution containing copper and sulfuric acid, containing 20 to 50 ppm of chlorine, 1 to 10 ppm of a thiourea compound, and 1 to 20 ppm of a water-soluble polymer compound. In this case, an electrolytic copper foil having an average number of intersection points between an arbitrary line segment having a length of 500 nm and a twin plane which is a (111) Σ 3 grain boundary can be produced.
さらに、硫酸－硫酸銅電解めっき液に遷移金属元素を加えることで、耐熱性を更に向上させることができる。添加する金属元素は、望ましくは硫酸酸性水溶液中で酸化物が安定な元素であり、更に望ましくは３価以上の多価酸化物を安定にとりうる元素である。
Furthermore, the heat resistance can be further improved by adding a transition metal element to the sulfuric acid-copper sulfate electroplating solution. The metal element to be added is preferably an element in which an oxide is stable in a sulfuric acid aqueous solution, and more preferably an element capable of stably taking a trivalent or higher polyvalent oxide.
本実施形態の電解銅箔の製造方法では、ＴＥＭ画像における５００ｎｍの長さの任意の線分と（１１１）Σ３粒界である双晶面との交点の平均の数が５～４０となるように（１１１）Σ３粒界を数多く導入した結果、引張強度と導電率を共に向上できる電解銅箔の製造が可能となる。
In the method for producing an electrolytic copper foil according to the present embodiment, the average number of intersections between an arbitrary line segment having a length of 500 nm and a twin plane which is a (111) Σ3 grain boundary in a TEM image is 5 to 40. As a result of introducing a large number of (111) Σ3 grain boundaries, it is possible to produce an electrolytic copper foil that can improve both the tensile strength and the electrical conductivity.
なお本明細書においては、製造時に電解銅箔が陰極ドラム表面に接していた側の面をＳ面（光沢面）、逆の面をＭ面（マット面）と称している。
In the present specification, the surface on the side where the electrolytic copper foil is in contact with the surface of the cathode drum at the time of manufacture is referred to as the S surface (glossy surface), and the opposite surface is referred to as the M surface (matt surface).
製造された電解銅箔（未処理電解銅箔）に対して、例えば、クロメート処理、あるいはＮｉ又はＮｉ合金めっき、Ｃｏ又はＣｏ合金めっき、Ｚｎ又はＺｎ合金めっき、Ｓｎ又はＳｎ合金めっき、或いは上記各種めっき層上にさらにクロメート処理を施したもの等の無機防錆処理、あるいは、ベンゾトリアゾール等の有機防錆処理を施す。
さらに、例えばシランカップリング剤処理等が施されて、リチウムイオン二次電池負極集電体用電解銅箔として使用される。
上記無機防錆処理、有機防錆処理、シランカップリング剤処理は活物質との密着強度を高め、電池の充放電サイクル効率の低下を防ぐ役割を果たす。 For the produced electrolytic copper foil (untreated electrolytic copper foil), for example, chromate treatment, Ni or Ni alloy plating, Co or Co alloy plating, Zn or Zn alloy plating, Sn or Sn alloy plating, or the above various types An inorganic rust prevention treatment such as a chromate treatment on the plating layer, or an organic rust prevention treatment such as benzotriazole.
Furthermore, the silane coupling agent process etc. are given, for example, and it uses as an electrolytic copper foil for lithium ion secondary battery negative electrode collectors.
The inorganic rust prevention treatment, organic rust prevention treatment, and silane coupling agent treatment increase the adhesion strength with the active material and prevent the charge / discharge cycle efficiency of the battery from being lowered.
さらに、例えばシランカップリング剤処理等が施されて、リチウムイオン二次電池負極集電体用電解銅箔として使用される。
上記無機防錆処理、有機防錆処理、シランカップリング剤処理は活物質との密着強度を高め、電池の充放電サイクル効率の低下を防ぐ役割を果たす。 For the produced electrolytic copper foil (untreated electrolytic copper foil), for example, chromate treatment, Ni or Ni alloy plating, Co or Co alloy plating, Zn or Zn alloy plating, Sn or Sn alloy plating, or the above various types An inorganic rust prevention treatment such as a chromate treatment on the plating layer, or an organic rust prevention treatment such as benzotriazole.
Furthermore, the silane coupling agent process etc. are given, for example, and it uses as an electrolytic copper foil for lithium ion secondary battery negative electrode collectors.
The inorganic rust prevention treatment, organic rust prevention treatment, and silane coupling agent treatment increase the adhesion strength with the active material and prevent the charge / discharge cycle efficiency of the battery from being lowered.
また、上記の防錆処理を施す前に、例えば、電解銅箔表面に粗化処理を行う。この粗化処理としては、例えば、めっき法、エッチング法等が好適に採用できる。
めっき法は、未処理電解銅箔の表面に凹凸を有する薄膜層を形成することにより表面を粗化する方法である。めっき法としては、電解めっき法及び無電解めっき法を採用することができる。 Moreover, before performing said rust prevention process, a roughening process is performed to the electrolytic copper foil surface, for example. As this roughening treatment, for example, a plating method, an etching method, or the like can be suitably employed.
The plating method is a method of roughening the surface by forming a thin film layer having irregularities on the surface of the untreated electrolytic copper foil. As the plating method, an electrolytic plating method and an electroless plating method can be employed.
めっき法は、未処理電解銅箔の表面に凹凸を有する薄膜層を形成することにより表面を粗化する方法である。めっき法としては、電解めっき法及び無電解めっき法を採用することができる。 Moreover, before performing said rust prevention process, a roughening process is performed to the electrolytic copper foil surface, for example. As this roughening treatment, for example, a plating method, an etching method, or the like can be suitably employed.
The plating method is a method of roughening the surface by forming a thin film layer having irregularities on the surface of the untreated electrolytic copper foil. As the plating method, an electrolytic plating method and an electroless plating method can be employed.
めっき法による粗化としては、銅や銅合金などの銅を主成分とするめっき膜を、未処理電解銅箔表面に形成する方法が好ましい。
As the roughening by the plating method, a method of forming a plating film mainly composed of copper such as copper or copper alloy on the surface of the untreated electrolytic copper foil is preferable.
電気めっきにより粗化する方法としては、例えば、特許文献７に開示された、プリント回路用銅箔に対し一般的に用いられているめっきによる粗化方法が好ましく用いられる。すなわち、いわゆる「やけめっき」により、粒粉状銅めっき層を形成した後、この粒粉状銅めっき層の上に、その凹凸形状を損なわないように「被せめっき」を行い、実質的に平滑なめっき層を堆積させて粒粉状銅をいわゆるコブ状銅とする粗化方法である。
As a method of roughening by electroplating, for example, a roughening method by plating generally used for copper foil for printed circuits disclosed in Patent Document 7 is preferably used. That is, after forming a granular copper plating layer by so-called “bake plating”, “cover plating” is performed on this granular copper plating layer so as not to impair the uneven shape, thereby substantially smoothing. This is a roughening method in which a fine plating layer is deposited to turn the granular copper into a so-called bumpy copper.
エッチング法による粗化としては、例えば、物理的エッチングや化学的エッチングによる方法が適している。物理的エッチングにはサンドブラスト等でエッチングする方法があり、化学エッチングには処理液として、無機または有機酸と酸化剤と添加剤を含有する液が多数提案されている。例えば特許文献８では、無機酸＋過酸化水素＋トリアゾールなどの腐食防止剤＋界面活性剤が開示されている。また、特許文献９には、無機酸＋過酸化物＋アゾール＋ハロゲン化物を含有する液が開示されている。
通常は酸と酸化剤にキレート剤などの添加剤を付与した浴であり、銅の結晶粒界を優先的に溶解するものである。例えば、特許文献９に開示されている液組成の他に、メック株式会社のＣＺ－８１００、同８１０１、三菱ガス化学株式会社のＣＰＥ－９００などの市販品が採用できる。 As the roughening by the etching method, for example, a method by physical etching or chemical etching is suitable. For physical etching, there is a method of etching by sandblasting or the like, and for chemical etching, many liquids containing an inorganic or organic acid, an oxidizing agent, and an additive have been proposed. For example, Patent Literature 8 discloses a corrosion inhibitor such as an inorganic acid + hydrogen peroxide + triazole + a surfactant. Patent Document 9 discloses a liquid containing inorganic acid + peroxide + azole + halide.
Usually, it is a bath in which an additive such as a chelating agent is added to an acid and an oxidizing agent, and preferentially dissolves the copper grain boundaries. For example, in addition to the liquid composition disclosed in Patent Document 9, commercially available products such as CZ-8100 and 8101 of MEC Co., Ltd., and CPE-900 of Mitsubishi Gas Chemical Co., Ltd. can be adopted.
通常は酸と酸化剤にキレート剤などの添加剤を付与した浴であり、銅の結晶粒界を優先的に溶解するものである。例えば、特許文献９に開示されている液組成の他に、メック株式会社のＣＺ－８１００、同８１０１、三菱ガス化学株式会社のＣＰＥ－９００などの市販品が採用できる。 As the roughening by the etching method, for example, a method by physical etching or chemical etching is suitable. For physical etching, there is a method of etching by sandblasting or the like, and for chemical etching, many liquids containing an inorganic or organic acid, an oxidizing agent, and an additive have been proposed. For example, Patent Literature 8 discloses a corrosion inhibitor such as an inorganic acid + hydrogen peroxide + triazole + a surfactant. Patent Document 9 discloses a liquid containing inorganic acid + peroxide + azole + halide.
Usually, it is a bath in which an additive such as a chelating agent is added to an acid and an oxidizing agent, and preferentially dissolves the copper grain boundaries. For example, in addition to the liquid composition disclosed in Patent Document 9, commercially available products such as CZ-8100 and 8101 of MEC Co., Ltd., and CPE-900 of Mitsubishi Gas Chemical Co., Ltd. can be adopted.
本実施形態によれば、ＴＥＭ画像における５００ｎｍの長さの任意の線分と（１１１）Σ３粒界である双晶面との交点の平均の数が５～４０となるように（１１１）Σ３粒界を数多く導入した結果、引張強度と導電率が向上した電解銅箔を得ることができ、該電解銅箔を集電体とすることで、耐久性の向上、電池容量の増加、充放電特性の向上を実現したリチウムイオン二次電池を製造することができる。
According to the present embodiment, (111) Σ3 so that the average number of intersections between an arbitrary line segment having a length of 500 nm in a TEM image and a twin plane that is a (111) Σ3 grain boundary is 5 to 40. As a result of introducing many grain boundaries, an electrolytic copper foil with improved tensile strength and electrical conductivity can be obtained. By using the electrolytic copper foil as a current collector, durability is improved, battery capacity is increased, and charging / discharging is performed. A lithium ion secondary battery with improved characteristics can be manufactured.
本実施形態において、ＴＥＭ画像における５００ｎｍの長さの任意の線分と（１１１）Σ３粒界である双晶面との交点の数を求めるときの金属組織の観察は、透過電子顕微鏡（ＴＥＭ）で実施した。ＴＥＭ画像を図１に示す。
（１１１）Σ３粒界との交点の数は、図２に示すように、観察対象の組織上に５００ｎｍの長さの任意の線分を記入し、（１１１）Σ３粒界である双晶面との交点の数を求める。次に、前記線分の中点を中心に６０°ずつ回転させながら同様の線を引き、それぞれの線分と双晶面の交点の数を求め、各線と交差する双晶面との交点の数を平均し、「交点の数」とした。
また、そのときの双晶の間隔は０．１～５０ｎｍ、双晶が占める面積の割合は０．１～３０％であり、電子線回折から得られた回折像より、粒界は（１１１）Σ＃であることを確認した。
透過電子顕微鏡での観察はＪＥＭ－３０１０（日本電子社製）を使用し、加速電圧３００ｋＶで行った。観察視野は１０～３６万倍が望ましい。また、観察用試料作製は、ＴｅｎｕＰｏｌ－５（Ｓｔｒｕｅｒｓ社）を用いて実施した。
温度；－２６～―２５℃、電圧；８Ｖ、電解液； 硝酸：メタノール＝１：２。
また、平均結晶粒径の測定は、例えばインターセプト（Intercept）法により実施できる。インターセプト法では、観察対象の組織上に任意の線分を引き、線分の長さとそれに交わる結晶粒数から平均結晶粒径を求めるものである。 In this embodiment, the observation of the metal structure when obtaining the number of intersections between an arbitrary line segment having a length of 500 nm in the TEM image and the twin plane which is the (111) Σ3 grain boundary is performed by a transmission electron microscope (TEM). It carried out in. A TEM image is shown in FIG.
As shown in FIG. 2, the number of intersections with the (111) Σ3 grain boundary is an arbitrary line segment having a length of 500 nm on the structure to be observed, and the twin plane that is the (111) Σ3 grain boundary. Find the number of intersections with. Next, a similar line is drawn while rotating by 60 ° around the midpoint of the line segment, the number of intersections between each line segment and the twin plane is obtained, and the intersection of the twin plane intersecting each line is determined. The number was averaged to obtain the “number of intersections”.
At that time, the interval between twins was 0.1 to 50 nm, and the ratio of the area occupied by the twins was 0.1 to 30%. From the diffraction image obtained by electron beam diffraction, the grain boundary was (111) Confirmed to be Σ #.
Observation with a transmission electron microscope was performed using JEM-3010 (manufactured by JEOL Ltd.) at an acceleration voltage of 300 kV. The viewing field is preferably 100,000 to 360,000 times. Moreover, the sample preparation for observation was implemented using TenuPol-5 (Struers).
Temperature: −26 to −25 ° C., voltage: 8 V, electrolyte; nitric acid: methanol = 1: 2.
The average crystal grain size can be measured by, for example, an intercept method. In the intercept method, an arbitrary line segment is drawn on the structure to be observed, and the average crystal grain size is obtained from the length of the line segment and the number of crystal grains intersecting with the line segment.
（１１１）Σ３粒界との交点の数は、図２に示すように、観察対象の組織上に５００ｎｍの長さの任意の線分を記入し、（１１１）Σ３粒界である双晶面との交点の数を求める。次に、前記線分の中点を中心に６０°ずつ回転させながら同様の線を引き、それぞれの線分と双晶面の交点の数を求め、各線と交差する双晶面との交点の数を平均し、「交点の数」とした。
また、そのときの双晶の間隔は０．１～５０ｎｍ、双晶が占める面積の割合は０．１～３０％であり、電子線回折から得られた回折像より、粒界は（１１１）Σ＃であることを確認した。
透過電子顕微鏡での観察はＪＥＭ－３０１０（日本電子社製）を使用し、加速電圧３００ｋＶで行った。観察視野は１０～３６万倍が望ましい。また、観察用試料作製は、ＴｅｎｕＰｏｌ－５（Ｓｔｒｕｅｒｓ社）を用いて実施した。
温度；－２６～―２５℃、電圧；８Ｖ、電解液； 硝酸：メタノール＝１：２。
また、平均結晶粒径の測定は、例えばインターセプト（Intercept）法により実施できる。インターセプト法では、観察対象の組織上に任意の線分を引き、線分の長さとそれに交わる結晶粒数から平均結晶粒径を求めるものである。 In this embodiment, the observation of the metal structure when obtaining the number of intersections between an arbitrary line segment having a length of 500 nm in the TEM image and the twin plane which is the (111) Σ3 grain boundary is performed by a transmission electron microscope (TEM). It carried out in. A TEM image is shown in FIG.
As shown in FIG. 2, the number of intersections with the (111) Σ3 grain boundary is an arbitrary line segment having a length of 500 nm on the structure to be observed, and the twin plane that is the (111) Σ3 grain boundary. Find the number of intersections with. Next, a similar line is drawn while rotating by 60 ° around the midpoint of the line segment, the number of intersections between each line segment and the twin plane is obtained, and the intersection of the twin plane intersecting each line is determined. The number was averaged to obtain the “number of intersections”.
At that time, the interval between twins was 0.1 to 50 nm, and the ratio of the area occupied by the twins was 0.1 to 30%. From the diffraction image obtained by electron beam diffraction, the grain boundary was (111) Confirmed to be Σ #.
Observation with a transmission electron microscope was performed using JEM-3010 (manufactured by JEOL Ltd.) at an acceleration voltage of 300 kV. The viewing field is preferably 100,000 to 360,000 times. Moreover, the sample preparation for observation was implemented using TenuPol-5 (Struers).
Temperature: −26 to −25 ° C., voltage: 8 V, electrolyte; nitric acid: methanol = 1: 2.
The average crystal grain size can be measured by, for example, an intercept method. In the intercept method, an arbitrary line segment is drawn on the structure to be observed, and the average crystal grain size is obtained from the length of the line segment and the number of crystal grains intersecting with the line segment.
また、本実施形態において、引張強度は、ＩＰＣ規格（ＩＰＣ－ＴＭ－６５０）に定められた方法により、測定した値である。
また、本実施形態において、導電率はＩＰＣ規格（ＩＰＣ－ＴＭ－６５０）に基づき得られた比抵抗から算出した。 In this embodiment, the tensile strength is a value measured by a method defined in the IPC standard (IPC-TM-650).
In the present embodiment, the conductivity is calculated from the specific resistance obtained based on the IPC standard (IPC-TM-650).
また、本実施形態において、導電率はＩＰＣ規格（ＩＰＣ－ＴＭ－６５０）に基づき得られた比抵抗から算出した。 In this embodiment, the tensile strength is a value measured by a method defined in the IPC standard (IPC-TM-650).
In the present embodiment, the conductivity is calculated from the specific resistance obtained based on the IPC standard (IPC-TM-650).
以下、本発明を実施例に基づいてさらに詳細に説明するが、本発明は以下の実施例に何ら限定されるものではなく、その要旨を変更しない範囲において適宜変更して実施することが可能なものである。
Hereinafter, the present invention will be described in more detail based on examples. However, the present invention is not limited to the following examples, and can be implemented with appropriate modifications within a range not changing the gist thereof. Is.
［実施例１～１１］
［未処理銅箔の製造］
銅８０ｇ／Ｌ－硫酸４０～６０ｇ／Ｌの酸性銅電解浴に表１に示す組成の添加剤をそれぞれ添加し製箔用電解液を調製した。なお、実施例では塩化物イオン濃度を全て３０ｐｐｍに調整した。しかし、塩化物イオン濃度は電解条件により適宜変更するものであり、この濃度に限定されるものではない。
調製した電解液を用い、アノードには貴金属酸化物被覆チタン電極、カソードにはチタン製回転ドラムを用いて表１に示す電解条件（電流密度、液温）の下に、２０μｍ厚みの未処理銅箔を電解製箔法によって製造した。
[比較例１～３]
比較例１～３は表１に示す組成の電解液により２０μｍ厚みの未処理銅箔を製造した。
ここで、２Ｍ－５Ｓは２－メルカプト－５－ベンズイミダゾールスルホン酸であり、ＳＰＳはビス（３－スルホプロピル）ジスルフィドであり、ＤＤＡＣはジアリルジメチルアンモニウムクロライドでる。 [Examples 1 to 11]
[Manufacture of untreated copper foil]
An additive solution having the composition shown in Table 1 was added to an acidic copper electrolytic bath of copper 80 g / L-sulfuric acid 40-60 g / L to prepare an electrolytic solution for foil production. In the examples, the chloride ion concentration was all adjusted to 30 ppm. However, the chloride ion concentration is appropriately changed depending on the electrolysis conditions, and is not limited to this concentration.
Using the prepared electrolytic solution, a noble metal oxide-coated titanium electrode for the anode, and a titanium rotating drum for the cathode, under the electrolysis conditions (current density, liquid temperature) shown in Table 1, 20 μm-thick untreated copper The foil was produced by an electrolytic foil method.
[Comparative Examples 1 to 3]
In Comparative Examples 1 to 3, an untreated copper foil having a thickness of 20 μm was produced from an electrolytic solution having the composition shown in Table 1.
Here, 2M-5S is 2-mercapto-5-benzimidazolesulfonic acid, SPS is bis (3-sulfopropyl) disulfide, and DDAC is diallyldimethylammonium chloride.
［未処理銅箔の製造］
銅８０ｇ／Ｌ－硫酸４０～６０ｇ／Ｌの酸性銅電解浴に表１に示す組成の添加剤をそれぞれ添加し製箔用電解液を調製した。なお、実施例では塩化物イオン濃度を全て３０ｐｐｍに調整した。しかし、塩化物イオン濃度は電解条件により適宜変更するものであり、この濃度に限定されるものではない。
調製した電解液を用い、アノードには貴金属酸化物被覆チタン電極、カソードにはチタン製回転ドラムを用いて表１に示す電解条件（電流密度、液温）の下に、２０μｍ厚みの未処理銅箔を電解製箔法によって製造した。
[比較例１～３]
比較例１～３は表１に示す組成の電解液により２０μｍ厚みの未処理銅箔を製造した。
ここで、２Ｍ－５Ｓは２－メルカプト－５－ベンズイミダゾールスルホン酸であり、ＳＰＳはビス（３－スルホプロピル）ジスルフィドであり、ＤＤＡＣはジアリルジメチルアンモニウムクロライドでる。 [Examples 1 to 11]
[Manufacture of untreated copper foil]
An additive solution having the composition shown in Table 1 was added to an acidic copper electrolytic bath of copper 80 g / L-sulfuric acid 40-60 g / L to prepare an electrolytic solution for foil production. In the examples, the chloride ion concentration was all adjusted to 30 ppm. However, the chloride ion concentration is appropriately changed depending on the electrolysis conditions, and is not limited to this concentration.
Using the prepared electrolytic solution, a noble metal oxide-coated titanium electrode for the anode, and a titanium rotating drum for the cathode, under the electrolysis conditions (current density, liquid temperature) shown in Table 1, 20 μm-thick untreated copper The foil was produced by an electrolytic foil method.
[Comparative Examples 1 to 3]
In Comparative Examples 1 to 3, an untreated copper foil having a thickness of 20 μm was produced from an electrolytic solution having the composition shown in Table 1.
Here, 2M-5S is 2-mercapto-5-benzimidazolesulfonic acid, SPS is bis (3-sulfopropyl) disulfide, and DDAC is diallyldimethylammonium chloride.
［電解銅箔の特性の測定］
各電解銅箔（実施例１～１１，比較例１～３）の引張強度（ＭＰａ）、平均粒径、（１１１）Σ３粒界の有無及び５００ｎｍの長さの任意の線分と（１１１）Σ３粒界である双晶面との交点の平均の数（以下、交点の数と称する）、導電率ＥＣ{％ＩＡＣＳ（International Annealed Copper Standard）}を測定し、総合評価を行った。結果を表２に示す。また、引張強度は引張試験機（インストロン社製１１２２型）を用いて測定した。 [Measurement of characteristics of electrolytic copper foil]
Tensile strength (MPa) of each electrolytic copper foil (Examples 1 to 11, Comparative Examples 1 to 3), average particle diameter, presence / absence of (111) Σ3 grain boundary, and an arbitrary line segment having a length of 500 nm and (111) The average number of intersections (hereinafter referred to as the number of intersections) with the twin plane, which is the Σ3 grain boundary, and the electrical conductivity EC {% IACS (International Annealed Copper Standard)} were measured for comprehensive evaluation. The results are shown in Table 2. The tensile strength was measured using a tensile testing machine (Instron type 1122).
各電解銅箔（実施例１～１１，比較例１～３）の引張強度（ＭＰａ）、平均粒径、（１１１）Σ３粒界の有無及び５００ｎｍの長さの任意の線分と（１１１）Σ３粒界である双晶面との交点の平均の数（以下、交点の数と称する）、導電率ＥＣ{％ＩＡＣＳ（International Annealed Copper Standard）}を測定し、総合評価を行った。結果を表２に示す。また、引張強度は引張試験機（インストロン社製１１２２型）を用いて測定した。 [Measurement of characteristics of electrolytic copper foil]
Tensile strength (MPa) of each electrolytic copper foil (Examples 1 to 11, Comparative Examples 1 to 3), average particle diameter, presence / absence of (111) Σ3 grain boundary, and an arbitrary line segment having a length of 500 nm and (111) The average number of intersections (hereinafter referred to as the number of intersections) with the twin plane, which is the Σ3 grain boundary, and the electrical conductivity EC {% IACS (International Annealed Copper Standard)} were measured for comprehensive evaluation. The results are shown in Table 2. The tensile strength was measured using a tensile testing machine (Instron type 1122).
また、（１１１）Σ３粒界の有無及び交点の数は、透過電子顕微鏡において観察視野は１０～３６万倍として金属組織観察をして求めた。
また、金属組織観察において１０ｎｍ以上連続で直線上であるものを（１１１）Σ３粒界とした。 The presence or absence of the (111) Σ3 grain boundary and the number of intersections were determined by observing the metal structure with a transmission electron microscope with an observation field of 100 to 360,000 times.
In addition, the (111) Σ3 grain boundary was defined as a continuous and linear line of 10 nm or more in the metal structure observation.
また、金属組織観察において１０ｎｍ以上連続で直線上であるものを（１１１）Σ３粒界とした。 The presence or absence of the (111) Σ3 grain boundary and the number of intersections were determined by observing the metal structure with a transmission electron microscope with an observation field of 100 to 360,000 times.
In addition, the (111) Σ3 grain boundary was defined as a continuous and linear line of 10 nm or more in the metal structure observation.
図１及び図２は、本実施例に係るＴＥＭ画像である。
「交点の数」は、図２に示すように、観察対象の組織上に５００ｎｍの長さの任意の線分を記入し、（１１１）Σ３粒界である双晶面との交点の数を求め、次に、前記線分の中点を中心に６０°ずつ回転させながら同様の線を引き、それぞれの線分と双晶面の交点の数を求め、各線と交差する双晶面との交点の数を平均し、「交点の数」とした。 1 and 2 are TEM images according to the present example.
As shown in FIG. 2, the “number of intersection points” is an arbitrary line segment having a length of 500 nm on the structure to be observed, and the number of intersection points with the twin plane which is the (111) Σ3 grain boundary. Next, a similar line is drawn while rotating by 60 ° around the midpoint of the line segment, the number of intersections between each line segment and the twin plane is obtained, and the twin plane intersecting each line is determined. The number of intersections was averaged to obtain the “number of intersections”.
「交点の数」は、図２に示すように、観察対象の組織上に５００ｎｍの長さの任意の線分を記入し、（１１１）Σ３粒界である双晶面との交点の数を求め、次に、前記線分の中点を中心に６０°ずつ回転させながら同様の線を引き、それぞれの線分と双晶面の交点の数を求め、各線と交差する双晶面との交点の数を平均し、「交点の数」とした。 1 and 2 are TEM images according to the present example.
As shown in FIG. 2, the “number of intersection points” is an arbitrary line segment having a length of 500 nm on the structure to be observed, and the number of intersection points with the twin plane which is the (111) Σ3 grain boundary. Next, a similar line is drawn while rotating by 60 ° around the midpoint of the line segment, the number of intersections between each line segment and the twin plane is obtained, and the twin plane intersecting each line is determined. The number of intersections was averaged to obtain the “number of intersections”.
また、導電率は、ＩＰＣ規格（ＩＰＣ－ＴＭ－６５０）に基づき得られた比抵抗から算出した値である。
総合評価は、引張強度と導電率がともに良好なものが○、やや良好なものが△、いずれか一方でも不良のものを×とした。 The conductivity is a value calculated from the specific resistance obtained based on the IPC standard (IPC-TM-650).
In the comprehensive evaluation, “Good” indicates that both the tensile strength and the electrical conductivity are good, “Fair” indicates that the tensile strength and electrical conductivity are good, and “Poor” indicates that one of them is defective.
総合評価は、引張強度と導電率がともに良好なものが○、やや良好なものが△、いずれか一方でも不良のものを×とした。 The conductivity is a value calculated from the specific resistance obtained based on the IPC standard (IPC-TM-650).
In the comprehensive evaluation, “Good” indicates that both the tensile strength and the electrical conductivity are good, “Fair” indicates that the tensile strength and electrical conductivity are good, and “Poor” indicates that one of them is defective.
表２に示すように、ＴＥＭ画像における５００ｎｍの長さの任意の線分と（１１１）Σ３粒界である双晶面との交点の平均の数が５～４０である実施例１～１１は、引張強度と導電率がともに良好であった。
一方、比較例１～３では、引張強度と導電率のいずれかが不良であった。 As shown in Table 2, Examples 1 to 11 in which the average number of intersection points between an arbitrary line segment having a length of 500 nm in a TEM image and a twin plane which is a (111) Σ 3 grain boundary are 5 to 40 are as follows: Both tensile strength and electrical conductivity were good.
On the other hand, in Comparative Examples 1 to 3, either the tensile strength or the conductivity was poor.
一方、比較例１～３では、引張強度と導電率のいずれかが不良であった。 As shown in Table 2, Examples 1 to 11 in which the average number of intersection points between an arbitrary line segment having a length of 500 nm in a TEM image and a twin plane which is a (111) Σ 3 grain boundary are 5 to 40 are as follows: Both tensile strength and electrical conductivity were good.
On the other hand, in Comparative Examples 1 to 3, either the tensile strength or the conductivity was poor.
本発明の電解銅箔は、リチウムイオン二次電池以外の用途として、たとえば、回路基板用銅箔、電子デバイス材料としても、好ましく使用することができる。
The electrolytic copper foil of the present invention can be preferably used for applications other than lithium ion secondary batteries, for example, as a copper foil for circuit boards and electronic device materials.
Claims (5)
- 銅を含む電解液を電析することにより作られる電解銅箔において、
透過電子顕微鏡観察像において、５００ｎｍの長さの任意の線分と（１１１）Σ３粒界である双晶面との交点の平均の数が５～４０であることを特徴とする電解銅箔。 In the electrolytic copper foil made by electrodepositing an electrolytic solution containing copper,
An electrolytic copper foil characterized in that the average number of intersections between an arbitrary line segment having a length of 500 nm and a twin plane which is a (111) Σ 3 grain boundary in a transmission electron microscope observation image is 5 to 40. - 銅を含む電解液を電析することにより作られる電解銅箔において、
透過電子顕微鏡観察像において、５００ｎｍの長さの任意の線分と（１１１）Σ３粒界である双晶面との交点の平均の数が１０～３６であることを特徴とする電解銅箔。 In the electrolytic copper foil made by electrodepositing an electrolytic solution containing copper,
An electrolytic copper foil characterized in that, in a transmission electron microscope observation image, the average number of intersections between an arbitrary line segment having a length of 500 nm and a twin plane which is a (111) Σ 3 grain boundary is 10 to 36. - 銅及び硫酸を含み、添加剤として塩素を２０～５０ｐｐｍ、チオ尿素系化合物を１～１０ｐｐｍ、水溶性高分子系化合物を１～２０ｐｐｍ含有する電解めっき液で電解処理を行い、透過電子顕微鏡観察像において、５００ｎｍの長さの任意の線分と（１１１）Σ３粒界である双晶面との交点の平均の数が５～４０である電解銅箔を製造する、電解銅箔の製造方法。 Electrolytic treatment with an electroplating solution containing copper and sulfuric acid, containing 20 to 50 ppm chlorine as additive, 1 to 10 ppm thiourea compound, and 1 to 20 ppm water-soluble polymer compound, and observed by transmission electron microscope The method for producing an electrolytic copper foil, comprising producing an electrolytic copper foil having an average number of intersection points of an arbitrary line segment having a length of 500 nm and a twin plane which is a (111) Σ3 grain boundary.
- 請求項１または２に記載の電解銅箔を用いたリチウムイオン二次電池の負極電極。 A negative electrode of a lithium ion secondary battery using the electrolytic copper foil according to claim 1 or 2.
- 請求項１または２に記載の電解銅箔を用いたリチウムイオン二次電池。 A lithium ion secondary battery using the electrolytic copper foil according to claim 1 or 2.
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| JP2001011685A (en) * | 1999-06-30 | 2001-01-16 | Mitsui Mining & Smelting Co Ltd | Electrolytic copper foil and its production |
| JP2001123289A (en) * | 1999-10-27 | 2001-05-08 | Dowa Mining Co Ltd | Electrolytic copper foil and method for manufacturing the same |
| JP2001181886A (en) * | 1999-12-28 | 2001-07-03 | Mitsui Mining & Smelting Co Ltd | Electrolytic copper foil |
| JP2002053993A (en) * | 2000-08-04 | 2002-02-19 | Mitsui Mining & Smelting Co Ltd | Electrolytic copper foil, and method of manufacturing the same |
| JP2009299100A (en) * | 2008-06-10 | 2009-12-24 | Mitsui Mining & Smelting Co Ltd | Electrolytic copper foil and method for manufacturing electrolytic copper foil |
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| JP2001011685A (en) * | 1999-06-30 | 2001-01-16 | Mitsui Mining & Smelting Co Ltd | Electrolytic copper foil and its production |
| JP2001123289A (en) * | 1999-10-27 | 2001-05-08 | Dowa Mining Co Ltd | Electrolytic copper foil and method for manufacturing the same |
| JP2001181886A (en) * | 1999-12-28 | 2001-07-03 | Mitsui Mining & Smelting Co Ltd | Electrolytic copper foil |
| JP2002053993A (en) * | 2000-08-04 | 2002-02-19 | Mitsui Mining & Smelting Co Ltd | Electrolytic copper foil, and method of manufacturing the same |
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