JP2013028857A - Rolled copper foil and lithium ion secondary battery negative electrode using the same - Google Patents

Rolled copper foil and lithium ion secondary battery negative electrode using the same Download PDF

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JP2013028857A
JP2013028857A JP2011167281A JP2011167281A JP2013028857A JP 2013028857 A JP2013028857 A JP 2013028857A JP 2011167281 A JP2011167281 A JP 2011167281A JP 2011167281 A JP2011167281 A JP 2011167281A JP 2013028857 A JP2013028857 A JP 2013028857A
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copper foil
additive element
ion secondary
lithium ion
rolled copper
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Yoshiki Sawai
祥束 沢井
Tomio Iwasaki
富生 岩崎
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Hitachi Cable Ltd
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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
    • H01M4/662—Alloys
    • 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
    • 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
    • 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
    • C22C9/01—Alloys based on copper with aluminium as the next major constituent
    • 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
    • C22C9/02—Alloys based on copper with tin as the next major constituent
    • 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
    • C22C9/04—Alloys based on copper with zinc as the next major constituent
    • 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
    • C22C9/05—Alloys based on copper with manganese as the next major constituent
    • 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
    • C22C9/06—Alloys based on copper with nickel or cobalt as the next major constituent
    • 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
    • C22C9/10—Alloys based on copper with silicon as the next major constituent
    • 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

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  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
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  • Manufacturing & Machinery (AREA)
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  • Organic Chemistry (AREA)
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  • Battery Electrode And Active Subsutance (AREA)

Abstract

PROBLEM TO BE SOLVED: To provide rolled copper foil which has not only high strength, high heat resistance, high conductivity and excellent workability or the like but also high adhesion with a resin included in a negative electrode active material layer without executing roughening treatment by plating of electrodeposition grains or the like onto a copper foil surface, and a lithium ion secondary battery negative electrode using the rolled copper foil.SOLUTION: The rolled copper foil includes a copper alloy composition which has Cu as a main component and contains an additional element A comprising one or more kinds of elements whose atomic radius is smaller than that of Cu and inevitable impurities. When the total sum of (difference in the atomic radius between each additional element constituting the additional element A and Cu)×(atom% of each additional element) is defined as the change amount of an interatomic distance due to the additional element A, the change amount of the interatomic distance is -0.002 picometers (pm) or less, and the total amount of the additional element A is 1.0 wt.% or less when the total amount of the copper alloy composition is 100 pts.wt.

Description

本発明は、リチウムイオン二次電池の集電体に好適で、優れた樹脂密着性を有する圧延銅箔及び該圧延銅箔を用いたリチウムイオン二次電池負極に関するものである。   The present invention relates to a rolled copper foil that is suitable for a current collector of a lithium ion secondary battery and has excellent resin adhesion, and a lithium ion secondary battery negative electrode using the rolled copper foil.

リチウムイオン二次電池は高い電圧が得られ、エネルギー密度も高いことからモバイルパソコン、携帯端末等の電子機器のバッテリーとして利用されており、さらには自動車の駆動用電池としても多くの機関で研究開発が活発に行われている。 Lithium ion secondary batteries are used as batteries for electronic devices such as mobile personal computers and portable terminals because of their high voltage and high energy density, and they are also researched and developed by many organizations as driving batteries for automobiles. Is being actively conducted.

リチウムイオン二次電池は、電解質中のリチウムイオンがセパレーターによって絶縁された正極板と負極板の間を移動することによって充放電を繰り返す仕組みを基本とし、この仕組みを高いサイクル特性で実現できる電解質、セパレーター、正極板及び負極板の材料を見出すことが重要である。   The lithium ion secondary battery is based on a mechanism that repeats charging and discharging by moving between the positive electrode plate and the negative electrode plate in which the lithium ions in the electrolyte are insulated by the separator, an electrolyte that can realize this mechanism with high cycle characteristics, a separator, It is important to find materials for the positive and negative plates.

リチウムイオン二次電池に使用する負極板は、銅箔を材料とする負極集電体とその上に形成される負極活性物質層によって構成されるのが一般的である。   A negative electrode plate used for a lithium ion secondary battery is generally composed of a negative electrode current collector made of copper foil and a negative electrode active material layer formed thereon.

負極集電体を構成する銅箔には、鋳造で製造した肉厚の素条に圧延加工を施して製造する圧延銅箔や、銅イオンを含む電解液から金属銅を電析させて製造する電解銅箔が使用されている。この中で、圧延銅箔は、圧延加工と加熱処理を組み合わせることによって、銅箔及び銅合金箔の銅結晶組織を制御できるという特徴を有する。   The copper foil constituting the negative electrode current collector is produced by electrodepositing metal copper from a rolled copper foil produced by rolling a thick strip produced by casting or an electrolytic solution containing copper ions. Electrolytic copper foil is used. Among these, the rolled copper foil has a feature that the copper crystal structure of the copper foil and the copper alloy foil can be controlled by combining the rolling process and the heat treatment.

銅箔の表面に形成される負極活物質層は、主に１００μｍ程度の膜厚を有し、人工黒鉛や天然黒鉛、あるいはコークス等のカーボン粒をポリ弗化ビニリデン（ＰＶｄＦ）等のバインダ及び導電助剤と一緒にＮ−メチル−２−ピロリドン（ＮＭＰ）等の溶剤に混合しスラリー状にした後、これを銅箔の表面に塗布し、乾燥固化させることによって得られる。   The negative electrode active material layer formed on the surface of the copper foil mainly has a film thickness of about 100 μm, and carbon particles such as artificial graphite, natural graphite, or coke are bonded with a binder such as polyvinylidene fluoride (PVdF) and conductive material. It is obtained by mixing it with a solvent such as N-methyl-2-pyrrolidone (NMP) together with an auxiliary agent to form a slurry, and applying this to the surface of the copper foil, followed by drying and solidifying.

リチウムイオン二次電池では、充放電を繰り返すと、リチウムの吸蔵・放出に伴うカーボン粒の膨張・収縮によってカーボンが銅箔から剥離しやすく、電極間の短絡、電池容量の低下とサイクル特性の劣化等を招く恐れがある。そのため、負極集電体用銅箔として、負極活物質層を構成するカーボンとの高い密着性が要求されている。カーボンとの密着性はスラリー中のバインダの割合を多くすればある程度向上できるが、逆に電極の導電性が低下してしまうため有効な手段ではない。   In lithium-ion secondary batteries, when charging and discharging are repeated, carbon easily peels from the copper foil due to the expansion and contraction of carbon particles accompanying the insertion and extraction of lithium, resulting in a short circuit between electrodes, a decrease in battery capacity, and deterioration in cycle characteristics Etc. Therefore, high adhesiveness with the carbon which comprises a negative electrode active material layer is requested | required as copper foil for negative electrode collectors. Adhesion with carbon can be improved to some extent by increasing the binder ratio in the slurry, but it is not an effective means because the conductivity of the electrode is reduced.

そこで、この問題を解決するため、予め粗化と呼ばれる銅箔表面に凹凸を形成する表面処理を施すことが行われている。粗化処理の方法としては、ブラスト処理、粗面ロールによる圧延、機械研磨、電解研磨、化学研磨及び電着粒のめっき等の方法が知られているが、これらの中でも特に電着粒のめっきは多用されている。特許文献１〜３には、これらの方法で表面粗化処理することによって、負極活物質層との密着性の向上や充放電時負極集電体に集中する応力緩和を図ったリチウムイオン二次電池用銅箔が提案されている。それらの中で、前記の特許文献１では、不均一で粗度が高い粗化粒子は逆に投錨効果が弱くなり、負極集電体と負極活物質との高い密着性が得られなくなるという問題を解決するために、低粗化度性の粗化粒子で銅箔表面上に複雑な構造を持たせるように、複数回のめっき処理やリフロー処理を施す方法が取られている。   Therefore, in order to solve this problem, surface treatment for forming irregularities on the surface of the copper foil called roughening has been performed in advance. As a method of roughening treatment, methods such as blasting, rolling with a rough surface roll, mechanical polishing, electrolytic polishing, chemical polishing, and plating of electrodeposited grains are known. Is heavily used. In Patent Documents 1 to 3, a lithium ion secondary that improves the adhesion with the negative electrode active material layer and relaxes stress concentrated on the negative electrode current collector during charge and discharge by surface roughening treatment by these methods. Battery copper foils have been proposed. Among them, in the above-mentioned Patent Document 1, the uneven and high roughness of the roughened particles, on the contrary, has a problem that the anchoring effect is weakened, and high adhesion between the negative electrode current collector and the negative electrode active material cannot be obtained. In order to solve this problem, a method of performing a plurality of plating treatments and reflow treatments so as to give a complicated structure on the surface of the copper foil with coarse particles having low roughening properties has been taken.

また、特許文献４には、リチウムイオン電池の集電体とケース樹脂との接合強度を高くするため、銅合金集電体をエッチング処理する方法が開示されており、銅集電体と樹脂との密着性を向上させる方法としては表面粗化処理が一般的に行われている。   Patent Document 4 discloses a method of etching a copper alloy current collector in order to increase the bonding strength between the current collector of the lithium ion battery and the case resin. As a method for improving the adhesion, surface roughening treatment is generally performed.

一方、リチウムイオン二次電池の負極集電体を構成する銅箔は、上記の負極活物質層との密着性を向上させるだけではなく、素材の基本的特性として、従来から高い強度、高耐熱性、高導電率及び良好な加工性等を有することが求められている。その方法として、特許文献５〜９には、Ｃｕ中にＣｒ、Ｚｒ、Ａｇ、Ｓｎ、Ｚｎ、Ｆｅ、Ｎｉ、Ｍｇ、Ｐ等の様々な元素を添加することが提案されている。また、特許文献１０には、導電率を低下させるような不純物元素を含む場合には、その総配合量をできるだけ少なくすることが開示されている。   On the other hand, the copper foil constituting the negative electrode current collector of the lithium ion secondary battery not only improves the adhesion with the negative electrode active material layer described above, but also has traditionally had high strength and high heat resistance as the basic characteristics of the material. It has been required to have high performance, high electrical conductivity and good workability. As the method, Patent Documents 5 to 9 propose adding various elements such as Cr, Zr, Ag, Sn, Zn, Fe, Ni, Mg, and P to Cu. Patent Document 10 discloses that when an impurity element that lowers the electrical conductivity is included, the total blending amount is reduced as much as possible.

特開２００９−８７５６１号公報JP 2009-87561 A 特開２００９−２７２０８６号公報JP 2009-272086 A 特開２００６−２１６５１８号公報JP 2006-216518 A 特開２０１０−２０５５０７号公報JP 2010-205507 A 特開２０００−３０３１２８号公報JP 2000-303128 A 特開２００２−３６３６６９号公報JP 2002-363669 A 特開平１１−３３９８１１号公報JP 11-339811 A 特開２００９−２４２８７１号公報JP 2009-242871 A 特開２００６−４０６７４号公報JP 2006-40674 A 特開平１１−８６８７１号公報JP 11-88671 A

しかしながら、前記の特許文献１〜４に記載されている方法は、粗化処理が必須の工程であるためにコストが高くなり、リチウムイオン二次電池の高価格化につながる。また、銅箔の量産を行う際に、上記の表面粗化処理方法を適用するには処理条件の精密な制御が必要であり、処理速度を速くして多量の処理を行う場合に、均一な品質を安定して得ることが困難である。そのため、上記の表面粗化処理方法を採用することは、コストだけではなく品質の点からも、電気自動車等のリチウムイオン二次電池を用いた機器の一般普及に大きな妨げとなっている。   However, since the methods described in Patent Documents 1 to 4 are steps in which roughening treatment is indispensable, the cost is increased and the cost of the lithium ion secondary battery is increased. In addition, when mass production of copper foil is performed, precise control of the processing conditions is necessary to apply the above surface roughening method, and it is uniform when a large amount of processing is performed at a high processing speed. It is difficult to obtain quality stably. Therefore, the use of the above surface roughening treatment method is a great hindrance to the general spread of equipment using lithium ion secondary batteries such as electric vehicles not only from the cost but also from the viewpoint of quality.

また、前記特許文献５〜１０には、リチウムイオン二次電池負極集電体用銅箔において強度、耐熱性、導電率及び加工性等を向上させる方法は開示されているものの、負極活物質層との密着性の向上については、その技術課題及び解決方法が記載や示唆がされていない。このように、従来技術では、負極活物質層との密着性を向上させる方法として表面粗化処理方法を採用するしか手段がなかった。   Further, although Patent Documents 5 to 10 disclose methods for improving strength, heat resistance, electrical conductivity, workability, and the like in a copper foil for a negative electrode current collector of a lithium ion secondary battery, a negative electrode active material layer As for the improvement in adhesion, the technical problem and the solution are not described or suggested. As described above, in the prior art, there is only means for adopting the surface roughening method as a method for improving the adhesion with the negative electrode active material layer.

本発明の目的は、上記のような従来技術における問題点を解決しようとするものであり、高強度、高耐熱性、高導電率又は良好な加工性を有するだけではなく、銅箔表面に電着粒のめっき等による粗化処理を施さずに負極活物質層に含まれる樹脂との密着性の高い圧延銅箔及び該圧延銅箔を用いたリチウムイオン二次電池負極を提供することにある。   The object of the present invention is to solve the problems in the prior art as described above, and not only has high strength, high heat resistance, high conductivity, or good workability, but also has an electric current on the surface of the copper foil. It is to provide a rolled copper foil having high adhesion to a resin contained in a negative electrode active material layer without performing a roughening treatment such as plating of grains, and a lithium ion secondary battery negative electrode using the rolled copper foil. .

本発明は、上記の目的を達成するために種々の検討を行った結果、圧延銅箔における添加元素の原子半径及び添加量と銅箔の樹脂密着性との間にある特定の相間関係を利用して、添加元素の組成を最適化することによって到達したものであり、次の構成を有する。
（１）本発明は、Ｃｕを主成分とし、Ｃｕより原子半径が小さな元素の１種又は２種以上からなる添加元素Ａと不可避不純物とを含有する銅合金組成を有し、（前記添加元素Ａを構成する各添加元素とＣｕとの原子半径の差）×（各添加元素の原子％）の総和を添加元素Ａによる原子間距離の変化量としたときに、該原子間距離の変化量が−０．００２ピコメーター（ｐｍ）以下であり、かつ前記添加元素Ａの総量が前記銅合金組成の総量を１００重量部としたときに１．０重量％以下であることを特徴とするリチウムイオン二次電池集電体用圧延銅箔を提供する。
（２）本発明は、前記添加元素Ａが、Ｂ、Ｂｅ、Ｃｏ、Ｃｒ、Ｆｅ、Ｇａ、Ｇｅ、Ｍｎ、Ｎｉ、Ｐ、Ｓ及びＳｉからなる元素群の中から選ばれる元素の１種又は２種以上（ただし、ＦｅとＰの２種類からなる添加元素は除く）であることを特徴とする前記（１）に記載のリチウムイオン二次電池集電体用圧延銅箔を提供する。
（３）本発明は、前記添加元素Ａの総量が前記銅合金組成の総量を１００重量部としたときに０．５重量％以下であることを特徴とする前記（１）又は（２）に記載のリチウムイオン二次電池集電体用圧延銅箔を提供する。
（４）本発明は、前記添加元素Ａに加えて、さらにＣｕより原子半径が大きな元素の１種又は２種以上からなる添加元素Ｂを含有する前記（１）〜（３）の何れかに記載のリチウムイオン二次電池集電体用圧延銅箔を提供する。
（５）本発明は、前記添加元素Ｂが、Ａｇ、Ａｌ、Ｉｎ、Ｍｇ、Ｓｎ、Ｔｉ、Ｚｎ及びＺｒからなる元素群の中から選ばれる元素の１種又は２種以上であることを特徴とする前記（１）〜（４）の何れかに記載のリチウムイオン二次電池集電体用圧延銅箔を提供する。
（６）本発明は、前記原子間距離の変化量が−０．００７ピコメーター（ｐｍ）以下となる前記（１）〜（５）の何れかに記載のリチウムイオン二次電池集電体用圧延銅箔を提供する。
（７）本発明は、前記の添加元素Ａと添加元素Ｂとの総量が、銅合金組成を１００重量部としたときに０．５重量％以下であることを特徴とする前記（４）〜（６）の何れかに記載のリチウムイオン二次電池集電体用圧延銅箔を提供する。
（８）本発明は、２０μｍ以下の厚さを有する前記（１）〜（７）の何れかに記載のリチウムイオン二次電池集電体用圧延銅箔を提供する。
（９）本発明は、前記（１）〜（８）の何れかに記載のリチウムイオン二次電池集電体用圧延銅箔を用いて、該リチウムイオン二次電池集電体用圧延銅箔の表面祖化処理を行わないで、前記圧延銅箔の表面上にバインダ樹脂を含む負極活物質層を形成したことを特徴とするリチウムイオン二次電池負極を提供する。 As a result of various studies to achieve the above object, the present invention utilizes a specific interrelationship between the atomic radius and addition amount of additive elements in rolled copper foil and the resin adhesion of copper foil. The present invention has been achieved by optimizing the composition of the additive element, and has the following configuration.
(1) The present invention has a copper alloy composition containing an additive element A composed of one or more elements having Cu as a main component and an atomic radius smaller than Cu and unavoidable impurities (the additive element) Amount of change in interatomic distance when the sum of the difference in atomic radius between each additive element constituting A and Cu) × (atomic% of each additive element) is the amount of change in interatomic distance due to additive element A In which lithium is not more than -0.002 picometer (pm) and the total amount of the additive element A is 1.0% by weight or less when the total amount of the copper alloy composition is 100 parts by weight. A rolled copper foil for an ion secondary battery current collector is provided.
(2) In the present invention, the additive element A is one of elements selected from the group consisting of B, Be, Co, Cr, Fe, Ga, Ge, Mn, Ni, P, S, and Si, or There is provided a rolled copper foil for a lithium ion secondary battery current collector as described in (1) above, which is at least two kinds (excluding additive elements composed of two kinds of Fe and P).
(3) In the present invention (1) or (2), the total amount of the additive element A is 0.5% by weight or less when the total amount of the copper alloy composition is 100 parts by weight. The rolled copper foil for lithium ion secondary battery collectors of description is provided.
(4) In addition to the additive element A, the present invention further includes any one of the above elements (1) to (3) containing an additive element B composed of one or more elements having an atomic radius larger than that of Cu. The rolled copper foil for lithium ion secondary battery collectors of description is provided.
(5) The present invention is characterized in that the additive element B is one or more elements selected from the group consisting of Ag, Al, In, Mg, Sn, Ti, Zn and Zr. The rolled copper foil for a lithium ion secondary battery current collector according to any one of (1) to (4).
(6) The present invention provides the current collector for a lithium ion secondary battery according to any one of (1) to (5), wherein an amount of change in the interatomic distance is −0.007 picometer (pm) or less. Provide rolled copper foil.
(7) In the present invention, the total amount of the additive element A and the additive element B is 0.5% by weight or less when the copper alloy composition is 100 parts by weight. (6) The rolled copper foil for lithium ion secondary battery collectors in any one of the above is provided.
(8) This invention provides the rolled copper foil for lithium ion secondary battery collectors in any one of said (1)-(7) which has a thickness of 20 micrometers or less.
(9) The present invention uses the rolled copper foil for a lithium ion secondary battery current collector according to any one of (1) to (8) above, and uses the rolled copper foil for the lithium ion secondary battery current collector. Thus, a negative electrode active material layer containing a binder resin is formed on the surface of the rolled copper foil without subjecting the surface to an electrode surface treatment, and a lithium ion secondary battery negative electrode is provided.

本発明の圧延銅箔は、Ｃｕを主成分とし、さらに強度、耐熱性又は加工性等を向上させる機能を有する元素を１種又は２種以上添加する際に、その添加量を最適化することによって、表面粗化処理を施さずに負極活物質層に含まれる樹脂との密着性を向上でき、リチウムイオン電池の長寿命化と安全性の向上に寄与し得る。さらに、添加元素の総量を所定の値以下に設定することによって、高い導電率を維持できるため、リチウムイオン二次電池の容量の向上を図ることができる。   When the rolled copper foil of the present invention contains one or more elements having Cu as a main component and further having the function of improving strength, heat resistance, workability, etc., the addition amount should be optimized. Thus, it is possible to improve the adhesion with the resin contained in the negative electrode active material layer without performing a surface roughening treatment, and to contribute to the extension of the life and safety of the lithium ion battery. Furthermore, by setting the total amount of additive elements to a predetermined value or less, high conductivity can be maintained, so that the capacity of the lithium ion secondary battery can be improved.

また、本発明の圧延銅箔は、強度、耐熱性又は加工性等の特性において少なくとも一つを向上させる機能を有する元素として原子半径がＣｕより小さい元素だけではなく、原子半径がＣｕより大きい元素を添加量（原子％）に基づく原子間距離の変化量が所定の値以下となるように、同時に添加することによって、強度、耐熱性、導電性及び加工性等の特性において少なくとも何れか一つを一層向上させることができるようになり、圧延銅箔として適用できる合金組成の幅が広がる。さらに、本発明の圧延銅箔は、厚みを２０μｍ以下にすることによって、リチウムイオン二次電池用負極に占める圧延銅箔の体積率が小さくなることから負極活物質を十分に充填できるようになり、電池の体積エネルギー密度を高くすることができる。   The rolled copper foil of the present invention is not only an element having an atomic radius smaller than Cu as an element having a function of improving at least one of properties such as strength, heat resistance or workability, but an element having an atomic radius larger than Cu. Is added at the same time so that the amount of change in interatomic distance based on the added amount (atomic%) is not more than a predetermined value, so that at least one of properties such as strength, heat resistance, conductivity, and workability is added. Can be further improved, and the range of alloy compositions applicable as rolled copper foil is widened. Furthermore, since the rolled copper foil of the present invention has a thickness of 20 μm or less, the volume ratio of the rolled copper foil in the negative electrode for lithium ion secondary batteries is reduced, so that the negative electrode active material can be sufficiently filled. The volume energy density of the battery can be increased.

加えて、本発明の圧延銅箔の表面上にバインダ樹脂を含む負極活物質層を形成したリチウムイオン二次電池負極は、従来コスト高の要因となっていた表面粗化処理工程を省略できるため、高性能、高信頼性及び高寿命のリチウムイオン電池を低コストで得ることができ、産業上極めて有効である。   In addition, the lithium ion secondary battery negative electrode in which the negative electrode active material layer containing the binder resin is formed on the surface of the rolled copper foil of the present invention can omit the surface roughening treatment step that has been a factor of high cost in the past. Therefore, a lithium ion battery with high performance, high reliability, and long life can be obtained at low cost, which is extremely effective in the industry.

Ｃｕより原子半径が小さな元素群Ａの例を示す図である。It is a figure which shows the example of the element group A whose atomic radius is smaller than Cu. Ｃｕより原子半径が小さな元素を添加したときに圧延面で起こる原子配列の変化を示す図である。It is a figure which shows the change of the atomic arrangement which occurs on a rolling surface when an element with an atomic radius smaller than Cu is added. Ｃｕより原子半径が大きな元素群Ｂの例を示す図である。It is a figure which shows the example of the element group B whose atomic radius is larger than Cu. Ｃｕより原子半径が大きな元素を添加したときに圧延面で起こる原子配列の変化を示す図である。It is a figure which shows the change of the atomic arrangement which occurs on a rolling surface when an element with an atomic radius larger than Cu is added. 本発明に係る圧延銅箔の製造工程の一例を示すフロー図である。It is a flowchart which shows an example of the manufacturing process of the rolled copper foil which concerns on this invention. 本発明の実施例におけるＣｕ合金材の合金組成、添加元素の総量、原子間距離の変化量、碁盤目試験の判定結果及び強度と導電率の測定結果を示す図である。It is a figure which shows the alloy composition of Cu alloy material in the Example of this invention, the total amount of an additive element, the variation | change_quantity of interatomic distance, the determination result of a cross-cut test, and the measurement result of intensity | strength and electrical conductivity. 本発明の別の実施例及び比較例におけるＣｕ合金材の合金組成、添加元素の総量、原子間距離の変化量、碁盤目試験の判定結果及び強度と導電率の測定結果を示す図である。It is a figure which shows the alloy composition of Cu alloy material in another Example of this invention, the total amount of an addition element, the variation | change_quantity of interatomic distance, the determination result of a cross-cut test, and the measurement result of intensity | strength and electrical conductivity.

以下、本発明の実施形態について図面を参照しつつ詳細に説明する。   Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

〈樹脂との密着性向上のメカニズム〉
添加元素を有する銅箔は、添加元素の原子半径とＣｕの原子半径（１２８ｐｍ）との差によって、結晶格子内に歪みが生じた後、その歪みの均一化が起こることで原子間距離が変化する。さらに、添加元素の添加量によって、結晶格子内に生じる歪み量が変化し、原子間距離の変化量を調整することが可能となる。 <Mechanism for improving adhesion to resin>
In the copper foil having an additive element, the distance between the atoms changes due to the distortion becoming uniform after the distortion occurs in the crystal lattice due to the difference between the atomic radius of the additive element and the atomic radius of Cu (128 pm). To do. Further, the amount of strain generated in the crystal lattice changes depending on the amount of additive element added, and the amount of change in interatomic distance can be adjusted.

銅箔の原子間距離の変化量ΔＲは、添加元素ｉの原子半径をＲｉ、圧延銅箔中に占める添加元素の割合を原子％によって規定したときの原子％をＸｉとすると、下記の式（１）で計算することができる。
ΔＲ＝Σ（Ｒｉ−１２８）×Ｘｉ （１）
ここで、各元素の原子％は、全構成元素における各元素の重量％と原子量から機械的に計算でき、前記圧延銅箔の後金成分から一意的に決定される。 The amount of change ΔR in the interatomic distance of the copper foil is expressed as follows, assuming that the atomic radius of the additive element i is R i and the atomic percentage when the proportion of the additive element in the rolled copper foil is defined by atomic% is X i . It can be calculated by equation (1).
ΔR = Σ (R i −128) × X i (1)
Here, the atomic% of each element can be mechanically calculated from the weight% and atomic weight of each element in all the constituent elements, and is uniquely determined from the post-metal component of the rolled copper foil.

本発明は、上記の原子間距離の変化量ΔＲに着目して、ΔＲが負になるようなときに負極活物質層にバインダとして含まれる樹脂との密着性が向上できることを見出して、到達したものである。すなわち、添加元素によって変化が起こり、その後圧延処理等によって均一化されて平均化したものとみなしたときの圧延銅箔の原子間距離がＣｕの原子間距離よりも小さくなると、樹脂との密着性が向上するという新しい知見に基づいてなされたものである。さらに、前記のΔＲが小さくなる（ΔＲの絶対値としては大きくなる）ほど、樹脂との密着性を上げる効果が大きくなることが分かった。   The present invention has been achieved by paying attention to the amount of change ΔR of the interatomic distance and finding that the adhesion to the resin contained as the binder in the negative electrode active material layer can be improved when ΔR becomes negative. Is. That is, when the interatomic distance of the rolled copper foil becomes smaller than the interatomic distance of Cu when it is assumed that the change is caused by the additive element and then uniformized and averaged by a rolling process or the like, the adhesiveness to the resin It was made based on the new knowledge that Furthermore, it has been found that the smaller the ΔR is (the larger the absolute value of ΔR is), the greater the effect of increasing the adhesion to the resin.

本発明においては、ΔＲが−０．００２ｐｍ以下でなければ樹脂との密着性を向上させる効果が得られない。本発明において、樹脂との密着性を大幅に向上するためには、ΔＲの値がさらに−０．００７ｐｍ以下であることが好ましい。ΔＲは、添加元素の原子半径と圧延銅箔中の割合（原子％）によって任意に調整することができる。ΔＲは、添加元素の割合（原子％）を増やすことによって小さくすることができるが、その値が小さすぎると、圧銅箔の導電率の低下が顕著になったり、結晶格子の歪みが大きくなって内部応力が増大する場合がある。ΔＲの下限値は、これらの特性に応じて任意に決めることができるが、本発明では導電率の低下や結晶内の内部応力の増大が顕著となることを防ぐため、−１．０００ｐｍに設定される。しかし、樹脂との密着性の向上効果は、ΔＲが−０．４００ｐｍより小さい場合は飽和する傾向にあるため、本発明において、ΔＲは−０．００２〜−１．０００ｐｍの範囲であり、好ましくは−０．００７〜−０．４００ｐｍの範囲である。   In the present invention, unless ΔR is −0.002 pm or less, the effect of improving the adhesion with the resin cannot be obtained. In the present invention, in order to significantly improve the adhesion to the resin, it is preferable that the value of ΔR is further −0.007 pm or less. ΔR can be arbitrarily adjusted by the atomic radius of the additive element and the ratio (atomic%) in the rolled copper foil. ΔR can be reduced by increasing the ratio (atomic%) of the additive element. However, if the value is too small, the decrease in the conductivity of the pressed copper foil becomes significant, or the distortion of the crystal lattice increases. Internal stress may increase. The lower limit value of ΔR can be arbitrarily determined according to these characteristics, but in the present invention, it is set to −1.000 pm in order to prevent the decrease in conductivity and the increase in internal stress in the crystal from becoming prominent. Is done. However, since the effect of improving the adhesion with the resin tends to be saturated when ΔR is smaller than −0.400 pm, in the present invention, ΔR is in the range of −0.002 to −1,000 pm, preferably Is in the range of -0.007 to -0.400 pm.

本発明において、樹脂との密着性が向上できるメカニズムについて詳細は不明であるが、次のように考えられる。   In the present invention, the details of the mechanism that can improve the adhesion to the resin are unknown, but are considered as follows.

原子間距離の変化量ΔＲは、元素ｉの原子半径をＲｉ、原子％をＸｉとすると、銅箔表面に塗布された負極活物質層に含まれる樹脂は、銅箔表面の原子と樹脂を構成する原子との間の原子間力、及び樹脂同士の分子間力によって決定される安定状態で銅箔表面上に固化すると考えられる。そこで、有機化合物である樹脂が有しているある特定の周期的な分子構造と銅箔表面の原子間距離との幾何的なマッチングを良くすることで、銅箔表面上に固化される樹脂の安定状態をさらに向上させることができ、銅箔の樹脂密着性を向上させることにつながると考えられる。一般に、樹脂に見られる周期的な分子構造は銅の原子間距離よりも小さいため、原子間距離の変化量ΔＲを負の値にすること、具体的には−０．００２ｐｍ以下にすることで、銅箔の樹脂密着性を向上させることができると推察される。 The amount of change ΔR in the interatomic distance is such that when the atomic radius of the element i is R i and the atomic% is X i , the resin contained in the negative electrode active material layer applied to the copper foil surface is composed of atoms and resins on the copper foil surface. It is thought that it solidifies on the surface of the copper foil in a stable state determined by the atomic force between the atoms constituting the and the intermolecular force between the resins. Therefore, by improving the geometric matching between the specific periodic molecular structure of the resin that is an organic compound and the interatomic distance of the copper foil surface, the resin solidified on the copper foil surface It is considered that the stable state can be further improved and the resin adhesion of the copper foil is improved. In general, since the periodic molecular structure found in the resin is smaller than the interatomic distance of copper, the amount of change ΔR in the interatomic distance is set to a negative value, specifically, −0.002 pm or less. It is speculated that the resin adhesion of the copper foil can be improved.

〈Ｃｕより小さな原子半径と有する添加元素Ａ〉
本発明は、Ｃｕを主成分とする銅箔において原子間距離の変化量を負の値にするために、Ｃｕより原子半径が小さな元素の１種又は２種以上を添加元素Ａとして銅箔の銅合金中に添加する。Ｃｕより原子半径が小さな元素としては様々な元素があるが、銅合金中に添加したときに導電率の低下が小さくて、かつ銅箔の強度、耐熱性又は加工性を向上できる元素として、図１に示すようなＢ、Ｂｅ、Ｃｏ、Ｃｒ、Ｆｅ、Ｇａ、Ｇｅ、Ｍｎ、Ｎｉ、Ｐ、Ｓ及びＳｉが好ましい。図１には、これらの元素の原子半径を合わせて示している。図１に示す各元素の原子半径は、丸善「日本金属学会編 金属データブック」から引用した文献値である。本発明は、図１に示す元素の他に、例えば、Ｓｅ（原子半径：１２０ｐｍ）、Ｏ（原子半径：７３ｐｍ）又はＮ（原子半径：７５ｐｍ）等の元素を、銅箔の強度、導電率及び加工性等の物性を大幅に低下させない量で添加しても良い。 <Additive element A with atomic radius smaller than Cu>
In the present invention, in order to make the change amount of the interatomic distance negative in a copper foil containing Cu as a main component, one or more elements having an atomic radius smaller than that of Cu are used as the additive element A for the copper foil. Add to copper alloy. There are various elements as elements having an atomic radius smaller than that of Cu. However, when added to a copper alloy, the decrease in conductivity is small, and the element that can improve the strength, heat resistance or workability of the copper foil is shown in FIG. B, Be, Co, Cr, Fe, Ga, Ge, Mn, Ni, P, S and Si as shown in FIG. FIG. 1 shows the atomic radii of these elements together. The atomic radius of each element shown in FIG. 1 is a literature value cited from Maruzen “Metal Data Book edited by the Japan Institute of Metals”. In the present invention, in addition to the elements shown in FIG. 1, for example, an element such as Se (atomic radius: 120 pm), O (atomic radius: 73 pm), or N (atomic radius: 75 pm) is added to the strength and conductivity of the copper foil. Further, it may be added in an amount that does not significantly reduce physical properties such as processability.

図２は、Ｃｕより原子半径が小さな元素を添加したときに圧延面で起こる原子配列の変化の模式的に表した図である。図２に示すように、結晶格子中の銅原子が図１に示す添加元素で置換されることによって導入される歪みは、圧延処理等によって圧延面で均一化されて、銅箔表面の結晶格子において元素間の原子間距離が平均的に小さくなるように作用する。それによって、銅箔の原子間距離は純銅の場合より小さくなり、原子間距離の変化量を負の値にする。ここで、原子間距離の平均的な変化量が０ｐｍ未満で−０．００２ｐｍを超える場合は、添加元素による歪みの導入が局所的であって歪みの量が小さいため、均一化による原子間距離の変化が非常に小さくなり、樹脂との密着性を向上する効果が十分に得られない。本発明は、原子間距離の平均的な変化量が−０．００２ｐｍ以下、好ましくは−０．００７ｐｍ以下において、本願発明の効果を奏するような樹脂との密着性を向上することができる。   FIG. 2 is a diagram schematically showing a change in atomic arrangement occurring on the rolling surface when an element having an atomic radius smaller than that of Cu is added. As shown in FIG. 2, the strain introduced by replacing the copper atoms in the crystal lattice with the additive element shown in FIG. 1 is made uniform on the rolling surface by a rolling process or the like, and the crystal lattice on the surface of the copper foil. Acts to reduce the interatomic distance between elements on average. Thereby, the interatomic distance of the copper foil is smaller than that of pure copper, and the change amount of the interatomic distance is set to a negative value. Here, when the average change amount of the interatomic distance is less than 0 pm and more than −0.002 pm, the introduction of strain by the additive element is local and the amount of strain is small. This change is very small, and the effect of improving the adhesion with the resin cannot be sufficiently obtained. The present invention can improve the adhesion with a resin that exhibits the effects of the present invention when the average change in the interatomic distance is −0.002 pm or less, preferably −0.007 pm or less.

リチウムイオン二次電池の使用用途は、電動バイクや電気自動車のモータ用電源等、高出入力・高容量化の方向へ移行している。高出入力の充放電の際には、リチウムイオン二次電池内に流れる電流が大きいため、電池集電体の直流抵抗が大きいと、リチウムイオン二次電池内に流れる電流とリチウムイオン二次電池の直流抵抗の積で表される初期電圧降下が大きくなり、十分なリチウムイオン二次電池の容量が得られにくくなる。そこで、リチウムイオン二次電池の直流抵抗を小さくすることによって初期電圧降下を抑制し、十分なリチウムイオン二次電池の容量を確保することができる。   Applications of lithium ion secondary batteries are shifting toward higher input / output capacity, such as power supplies for motors in electric motorcycles and electric vehicles. When charging / discharging high input / output, the current flowing in the lithium ion secondary battery is large. Therefore, if the DC resistance of the battery current collector is large, the current flowing in the lithium ion secondary battery and the lithium ion secondary battery The initial voltage drop represented by the product of the direct current resistance increases, and it becomes difficult to obtain a sufficient capacity of the lithium ion secondary battery. Therefore, by reducing the direct current resistance of the lithium ion secondary battery, the initial voltage drop can be suppressed, and a sufficient capacity of the lithium ion secondary battery can be secured.

そのため、本発明においてＣｕより原子半径が小さな元素の添加量は、銅箔を構成する銅合金組成の総量を１００重量部としたときに１重量％以下に設定する必要があり、好ましくは０．５重量％以下である。この添加量が１重量％を超えると、銅箔の導電率が顕著に低下するため、リチウムイオン二次電池集電体用銅箔として使用したときに、リチウムイオン電池の容量を十分に確保することができない。仮に、Ｃｕより原子半径が小さな元素の添加量が１重量％を超える場合でも、導電率の低下を抑制しようとすると、銅合金組成の詳細な検討、銅箔の製造方法及び条件等の変更、又は新たな製造工程の追加等を行う必要があり、本発明の効果である低コストの圧延銅箔を得ることが困難になる。Ｃｕより原子半径が小さな元素の添加量が１重量％以下であれば、銅合金組成を単純化することができ、製造方法も大きな変更を伴わないで所望の圧延銅箔を得ることができる。さらに、Ｃｕより原子半径が小さな元素の添加量が０．５重量％以下であれば、銅箔の導電率の低下を大幅に抑えることができる。本発明において、銅箔の導電率は７０％ＩＡＣＳ以上、好ましくは８０％ＩＡＣＳ以上であり、Ｃｕより原子半径が小さな元素の添加量が０．５重量％以下にすることによって、８０％ＩＡＣＳ以上を容易に満たすことができる。ここで、ＩＡＣＳは、 International Annealed Copper Standard（国際焼きなまし銅線標準）という名の "標準焼きなまし銅線" を １００％ とした場合の導線が何％の導電性をもつかという比較値で表されるものである。   Therefore, in the present invention, the addition amount of the element having an atomic radius smaller than that of Cu needs to be set to 1% by weight or less when the total amount of the copper alloy composition constituting the copper foil is 100 parts by weight, and preferably is set to 0.00%. 5% by weight or less. If the amount added exceeds 1% by weight, the conductivity of the copper foil is significantly reduced. Therefore, when used as a copper foil for a lithium ion secondary battery current collector, the capacity of the lithium ion battery is sufficiently secured. I can't. Even if the addition amount of an element having an atomic radius smaller than Cu exceeds 1% by weight, a detailed study of the copper alloy composition, changes in the manufacturing method and conditions of the copper foil, etc. Alternatively, it is necessary to add a new manufacturing process, and it becomes difficult to obtain a low-cost rolled copper foil that is an effect of the present invention. If the addition amount of the element having an atomic radius smaller than that of Cu is 1% by weight or less, the copper alloy composition can be simplified, and a desired rolled copper foil can be obtained without greatly changing the manufacturing method. Furthermore, if the addition amount of the element having an atomic radius smaller than that of Cu is 0.5% by weight or less, the decrease in the conductivity of the copper foil can be significantly suppressed. In the present invention, the conductivity of the copper foil is 70% IACS or more, preferably 80% IACS or more, and the addition amount of an element having an atomic radius smaller than Cu is 0.5% by weight or less, whereby 80% IACS or more. Can be easily met. Here, IACS is expressed as a comparison value of what percentage of electrical conductivity a conductor has when the standard annealed copper wire named International Annealed Copper Standard is 100%. Is.

Ｃｕより原子半径が小さな元素の添加量は、添加元素の原子半径に応じて変わり、上記の銅箔の原子間距離の変化量が−０．００２ｐｍ以下を満たす量であれば良いが、具体的には０．０５重量％以上、好ましくは０．１０重量％以上にすることによって、樹脂との密着性を向上できるだけではなく、添加元素による圧延銅箔の強度、熱的安定性又は加工性を向上させる効果を得ることができる。   The addition amount of an element having an atomic radius smaller than that of Cu varies depending on the atomic radius of the addition element, and may be any amount that satisfies the amount of change in the interatomic distance of the copper foil of −0.002 pm or less. In addition to improving the adhesion to the resin by making 0.05% by weight or more, preferably 0.10% by weight or more, the strength, thermal stability or workability of the rolled copper foil by the additive element is improved. The effect to improve can be acquired.

なお、Ｃｕより小さな原子半径と有する添加元素Ａの中で、ＦｅとＰの２種類からなる添加元素は、前記特許文献７の実施例１において、発明の思想が本発明とは全く異なるものの、同一組成を有し、表面粗化処理されていない銅合金圧延箔が記載されていることから、本発明からは除かれる。   In addition, among the additive element A having an atomic radius smaller than Cu, the additive element composed of two types of Fe and P is different from the present invention in Example 1 of Patent Document 7, although the idea of the invention is completely different from the present invention. Since copper alloy rolled foils having the same composition and not surface roughened are described, they are excluded from the present invention.

〈Ｃｕより大きな原子半径と有する添加元素Ｂ〉
本発明では、上記のＣｕより原子半径の小さな元素に加えて、Ｃｕより原子半径が大きな元素の１種又は２種以上を添加元素Ｂとして銅箔の銅合金中に添加することによって、圧延銅箔の強度、耐熱性、導電性及び加工性等の特性において少なくとも何れか一つをより向上させることができる。Ｃｕより原子半径が大きな元素としては様々な元素があるが、銅合金中に添加したときに、銅箔の強度、耐熱性、導電性又は加工性を向上できる元素として、図３に示すようなＡｇ、Ａｌ、Ｉｎ、Ｍｇ、Ｓｎ、Ｔｉ、Ｚｎ及びＺｒが好ましい。図３には、これらの元素の原子半径を合わせて示している。本発明は、図３に示す元素の他に、例えば、Ｃｄ（原子半径：１５５ｐｍ）、Ｓｂ（原子半径：２１５ｐｍ）又はＢｉ（原子半径：１６０ｐｍ）等の元素を、銅箔の強度、導電率及び加工性等の物性を大幅に低下させない量で添加しても良い。 <Additive element B with atomic radius larger than Cu>
In the present invention, in addition to the element having an atomic radius smaller than that of Cu, one or more elements having an atomic radius larger than Cu are added as additive element B to the copper alloy of the copper foil. At least one of the properties such as strength, heat resistance, conductivity, and workability of the foil can be further improved. Although there are various elements as elements having an atomic radius larger than that of Cu, as an element capable of improving the strength, heat resistance, conductivity or workability of copper foil when added to a copper alloy, as shown in FIG. Ag, Al, In, Mg, Sn, Ti, Zn and Zr are preferred. FIG. 3 shows the atomic radii of these elements together. In the present invention, in addition to the elements shown in FIG. 3, for example, an element such as Cd (atomic radius: 155 pm), Sb (atomic radius: 215 pm) or Bi (atomic radius: 160 pm) is added to the strength and conductivity of the copper foil. Further, it may be added in an amount that does not significantly reduce physical properties such as processability.

ここで、主成分であるＣｕと比べて原子半径が大きな元素を添加すると、銅箔表面の原子間距離が大きくなる。図４は、Ｃｕより原子半径が大きな元素だけを用いて銅合金に添加して、銅の結晶格子中にその元素だけを導入したときに圧延面で起こる原子配列の変化の模式的に表した図である。図４に示すように、結晶格子中の銅原子が図３に示す添加元素の置換によって導入される歪みは、圧延処理等によって圧延面で均一化されて、銅箔表面の結晶格子において元素間の原子間距離が平均的に大きくなるように作用する。それによって、銅箔の原子間距離は純銅の場合より大きくなり、原子間距離の変化量が正の値になる。銅箔表面の原子間距離の変化量が正の値になると、樹脂との密着性が低下する。したがって、本発明では、上記の添加元素Ａと添加元素Ｂとによって生じる銅箔の原子間距離の平均的な変化量が−０．００２ｐｍ以下、好ましくは−０．００７ｐｍ以下となるように、Ｃｕより原子半径が大きな元素の種類と添加量を決める必要がある。このようにすれば、Ｃｕより原子半径が大きな元素の１種又は２種以上を添加元素Ｂとして添加しても、樹脂との密着性を確保することができ、本発明の効果を奏するリチウムイオン二次電池集電体用銅箔を得ることができる。   Here, when an element having a larger atomic radius than Cu as the main component is added, the interatomic distance on the copper foil surface increases. FIG. 4 schematically shows a change in atomic arrangement that occurs on the rolling surface when only an element having an atomic radius larger than that of Cu is added to a copper alloy and only that element is introduced into the crystal lattice of copper. FIG. As shown in FIG. 4, the strain introduced by the substitution of the additive elements shown in FIG. 3 with the copper atoms in the crystal lattice is made uniform on the rolling surface by a rolling process or the like, and between the elements in the crystal lattice on the surface of the copper foil. It acts so that the interatomic distance of becomes larger on average. Thereby, the interatomic distance of the copper foil becomes larger than that of pure copper, and the change amount of the interatomic distance becomes a positive value. When the amount of change in the interatomic distance on the copper foil surface becomes a positive value, the adhesiveness with the resin decreases. Therefore, in the present invention, the average change amount of the interatomic distance of the copper foil caused by the additive element A and the additive element B is −0.002 pm or less, preferably −0.007 pm or less. It is necessary to determine the type and amount of elements with larger atomic radii. In this way, even if one or more elements having an atomic radius larger than that of Cu are added as additive element B, adhesion with the resin can be secured, and lithium ions exhibiting the effects of the present invention. A copper foil for a secondary battery current collector can be obtained.

また、上記の添加元素Ａの場合と同じ様に、添加元素Ｂを多量に添加すると銅箔の導電率の低下が顕著になり、結果的にリチウムイオン電池の容量を十分に確保することができなくなる。そのために、本発明では、上記の添加元素Ａと添加元素Ｂとの総量が銅合金組成を１００重量部としたときに１．０重量％以下であり、好ましくは０．５重量％以下である。銅箔の導電率は、上記の添加元素Ａと添加元素Ｂとの組合せにおいても、７０％ＩＡＣＳ以上、さらに８０％ＩＡＣＳ以上であることが好ましい。   Further, as in the case of the additive element A described above, when a large amount of the additive element B is added, the conductivity of the copper foil is significantly reduced, and as a result, a sufficient capacity of the lithium ion battery can be secured. Disappear. Therefore, in the present invention, the total amount of additive element A and additive element B is 1.0% by weight or less, preferably 0.5% by weight or less when the copper alloy composition is 100 parts by weight. . The conductivity of the copper foil is preferably 70% IACS or more, and more preferably 80% IACS or more, even in the combination of the additive element A and the additive element B.

〈圧延銅箔の厚さ〉
本発明において、圧延銅箔の厚みは、リチウムイオン電池の特性に応じて決めることができるが、２０μｍ以下であることが好ましい。厚みが２０μｍよりも厚い圧延銅箔では、これを用いて製造されたリチウムイオン二次電池において圧延銅箔の占める体積率が大きくなり負極活物質を十分に充填することができなくなり、体積エネルギー密度の低下を招く恐れがある。 <Rolled copper foil thickness>
In the present invention, the thickness of the rolled copper foil can be determined according to the characteristics of the lithium ion battery, but is preferably 20 μm or less. In the rolled copper foil having a thickness of more than 20 μm, the volume ratio occupied by the rolled copper foil is increased in the lithium ion secondary battery produced using this, and the negative electrode active material cannot be sufficiently filled, and the volume energy density There is a risk of lowering.

〈圧延銅箔の製造方法〉
図５は、本発明に係る圧延銅箔の製造方法の一例を示すフロー図である。 <Method for producing rolled copper foil>
FIG. 5 is a flowchart showing an example of a method for producing a rolled copper foil according to the present invention.

はじめに、原材料となる銅合金のインゴット（鋳塊）を用意する（工程１）。ここで、銅合金としては、Ｃｕを主成分として、Ｃｕより小さな原子半径と有する添加元素Ａ、好ましくはＢ、Ｂｅ、Ｃｏ、Ｃｒ、Ｆｅ、Ｇａ、Ｇｅ、Ｍｎ、Ｎｉ、Ｐ、Ｓ及びＳｉから選ばれる元素の１種又は２種以上からなる添加元素を含有し、添加元素の含有量が１重量％以下である銅合金を用いる。銅箔の強度、耐熱性、導電性および加工性の特性において何れか一つをさらに向上させたいときには、前記の添加元素Ａに加えて、Ｃｕより大きな原子半径を有する添加元素Ｂ、好ましくはＡｇ、Ａｌ、Ｉｎ、Ｍｇ、Ｓｎ、Ｔｉ、Ｚｎ及びＺｒから選ばれる元素の１種又は２種以上からなる添加元素を含有し、添加元素Ａと添加元素Ｂからなる添加元素の総含有量が１重量％以下である銅合金を用いる。   First, a copper alloy ingot (ingot) as a raw material is prepared (step 1). Here, as a copper alloy, an additive element A having Cu as a main component and an atomic radius smaller than Cu, preferably B, Be, Co, Cr, Fe, Ga, Ge, Mn, Ni, P, S, and Si A copper alloy containing an additive element consisting of one or more elements selected from the group consisting of 1 and 2% by weight or less is used. When it is desired to further improve any one of the strength, heat resistance, conductivity and workability characteristics of the copper foil, in addition to the additive element A, the additive element B having an atomic radius larger than Cu, preferably Ag , Al, In, Mg, Sn, Ti, Zn and an element selected from two or more elements selected from Zr and Zr, and the total content of the additive elements A and B is 1 A copper alloy having a weight percent or less is used.

次に、熱間圧延を行う熱間圧延工程（工程２）を行う。熱間圧延工程の後、冷間圧延を行う冷間圧延工程（工程３）と冷間圧延による加工硬度を緩和する中間焼鈍工程（工程４）とを適宜繰り返して行うことにより「生地」と呼ばれる銅条が製造される。引き続いて、生地焼鈍工程（工程４’）が行われる。生地焼鈍工程においては、その以前の加工ひずみが十分に緩和されることが望ましい。   Next, the hot rolling process (process 2) which performs hot rolling is performed. After the hot rolling process, a cold rolling process (process 3) in which cold rolling is performed and an intermediate annealing process (process 4) in which the processing hardness by cold rolling is relaxed are appropriately repeated and called “dough”. Copper strip is produced. Subsequently, a dough annealing step (step 4 ') is performed. In the dough annealing process, it is desirable that the previous processing strain is sufficiently relaxed.

その後、焼鈍した生地に対して最終冷間圧延工程（工程５、「仕上げ圧延工程」と称される場合もある）を施して所定厚さの圧延銅箔（工程６、「仕上げ銅箔」と称される場合もある）が製造される。最終冷間圧延工程（工程５）において総加工度を８５％以上９５％未満とすることにより、従来の高加工度圧延銅箔に対して圧延工程の総パス数を低減できるのに加えて、過度の加工硬化による圧延加工制御の困難性を回避でき、製造設備への負荷低減及び低コスト化に寄与できる。ここで、総加工度は下記の式（２）で定義される。
総加工度（％）＝｛１−（最終冷間圧延工程後の板厚／生地の板厚）｝×１００ （２） Thereafter, the annealed material is subjected to a final cold rolling step (step 5, sometimes referred to as “finishing rolling step”), and a rolled copper foil having a predetermined thickness (step 6, “finishing copper foil”) May be referred to). In addition to being able to reduce the total number of passes in the rolling process with respect to the conventional high workability rolled copper foil by making the total workability 85% or more and less than 95% in the final cold rolling process (process 5), The difficulty of controlling the rolling process due to excessive work hardening can be avoided, and the load on the manufacturing equipment can be reduced and the cost can be reduced. Here, the total processing degree is defined by the following equation (2).
Total degree of processing (%) = {1- (plate thickness after final cold rolling step / sheet thickness of dough)} × 100 (2)

最終冷間圧延工程後の圧延銅箔は、負極板製造工程（工程７）に供給される。工程７の最中（例えば、負極活物質塗布後の乾燥工程）やリチウムイオン二次電池組み込み後の乾燥工程において１００〜２００℃での熱処理が行われるのが一般的である。   The rolled copper foil after the final cold rolling process is supplied to the negative electrode plate manufacturing process (process 7). In general, heat treatment at 100 to 200 ° C. is performed during step 7 (for example, a drying step after application of the negative electrode active material) or in a drying step after incorporation of the lithium ion secondary battery.

このような特徴を有する製造方法によって作製された本発明の圧延銅箔は、高強度、高耐熱性、高導電率及び良好な加工性等を有するとともに、高い樹脂密着性と低コスト化を両立することができる。   The rolled copper foil of the present invention produced by the manufacturing method having such characteristics has high strength, high heat resistance, high electrical conductivity, good workability, etc., and at the same time, has high resin adhesion and low cost. can do.

〈リチウムイオン二次電池負極の製造方法〉
図５に示す負極板製造工程（工程７）を説明する。図５に示す工程１〜６を経て製造された圧延銅箔は、高い樹脂密着性を有するため表面粗化処理を行わないで、その上に直接、負極活物質層を形成する。負極活物質層は、ハードカーボンやソフトカーボン等の炭素系、人工黒鉛や天然黒鉛等の黒鉛系、チタン酸リチウム等の酸化物系又はＳｎやＳｉ複合材等の合金系を含む粒子を樹脂バインダに均一に混合した混合物が使用される。このとき、塗布前の樹脂バインダは、均一な混合又は圧延銅箔上の塗布性を考慮して、粘度を下げるためにｎ−メチルピロリドン（ＮＭＰ）等の溶剤を含む溶剤系バインダが一般的に使用される。また、溶剤使用によるハンドリング性の低下や環境負荷を考慮して、水系バインダを使用しても良い。樹脂バインダの均一混合と塗布が可能であれば、溶剤又は水を含まない樹脂バインダを使用することもできる。溶剤や水を含む場合には、樹脂バインダを塗布後、上記に述べたように１００〜２００℃で乾燥することによって、集電体を製造する。樹脂バインダとしては、ポリフッ化ビニリデン（ＰＶｄＦ）等のフッ素系樹脂、ポリアクリレート又はスチレンーブタジエンゴム（ＳＢＲ）等の耐熱性、機械的強度及び化学的安定性を有する樹脂であれば様々なものが使用できる。 <Method for producing negative electrode of lithium ion secondary battery>
The negative electrode plate manufacturing step (step 7) shown in FIG. 5 will be described. Since the rolled copper foil manufactured through steps 1 to 6 shown in FIG. 5 has high resin adhesion, a negative electrode active material layer is directly formed thereon without performing surface roughening treatment. The negative electrode active material layer is composed of carbon binder such as hard carbon and soft carbon, graphite such as artificial graphite and natural graphite, oxide such as lithium titanate or alloy such as Sn and Si composite material as a resin binder. A homogeneously mixed mixture is used. At this time, the resin binder before coating is generally a solvent-based binder containing a solvent such as n-methylpyrrolidone (NMP) in order to reduce the viscosity in consideration of uniform mixing or coating properties on the rolled copper foil. used. Further, an aqueous binder may be used in consideration of a decrease in handling property due to the use of a solvent and an environmental load. If the resin binder can be uniformly mixed and applied, a resin binder containing no solvent or water can be used. When a solvent or water is included, the current collector is manufactured by applying a resin binder and drying at 100 to 200 ° C. as described above. Various resin binders can be used as long as the resin has heat resistance, mechanical strength, and chemical stability, such as fluorine resin such as polyvinylidene fluoride (PVdF), polyacrylate or styrene-butadiene rubber (SBR). Can be used.

本発明において好適なリチウムイオン二次電池負極の構成は、表面粗化処理がされていない圧延銅箔の上に直接、導電性を有する炭素系又は黒鉛系からなる粒子と樹脂系バインダとからなる混合物を負極活物質層として形成した構成である。このようにして得られるリチウムイオン二次電池負極は、本発明の圧延銅箔を使用することによって、高強度、耐熱性、高導電率及び良好な加工性等を有し、かつ表面粗化処理を行わないでも高い樹脂密着性を有することから、高性能、高信頼性及び高寿命のリチウムイオン二次電池負極を低コストで得ることができる。   The lithium ion secondary battery negative electrode structure suitable for the present invention comprises a conductive carbon-based or graphite-based particle and a resin-based binder directly on a rolled copper foil that has not been surface-roughened. It is the structure which formed the mixture as a negative electrode active material layer. The lithium ion secondary battery negative electrode thus obtained has high strength, heat resistance, high electrical conductivity, good workability, etc., and surface roughening treatment by using the rolled copper foil of the present invention. Therefore, it is possible to obtain a high-performance, high-reliability and long-life lithium ion secondary battery negative electrode at low cost.

以下、実施例及び比較例に基づいて本発明をより具体的に説明するが、本発明は以下の実施例に限定されるものではない。   EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

［実施例１〜２６、比較例１〜１２］
無酸素銅を母材にして、図６及び図７に示す合金組成の銅合金を溶製し、インゴットに鋳造した。インゴットに熱間圧延を施した板材に対して、冷間圧延、生地焼鈍の順に施した後、８５〜９５％の加工度で最終冷間圧延を施して厚さ１０μｍとして、実施例１〜２６及び比較例１〜１２の圧延銅箔を得た。 [Examples 1 to 26, Comparative Examples 1 to 12]
Using oxygen-free copper as a base material, a copper alloy having the alloy composition shown in FIGS. 6 and 7 was melted and cast into an ingot. Examples 1 to 26 were applied to a plate obtained by hot rolling an ingot, followed by cold rolling and dough annealing, followed by final cold rolling at a working degree of 85 to 95% to a thickness of 10 μm. And the rolled copper foil of Comparative Examples 1-12 was obtained.

〈評価方法〉
それぞれの評価内容は以下の通りである。 <Evaluation method>
The contents of each evaluation are as follows.

（１）碁盤目試験
樹脂との密着性の評価方法として、次のような碁盤目試験を行った。実施例１〜２４及び比較例１〜１２で得られた圧延銅箔の上に、バインダ樹脂としてポリフッ化ビニリデン（ＰＶｄＦ）をｎ−メチルピロリドン（ＮＭＰ）溶媒に均一溶解した溶剤系バインダ樹脂を塗布した後、１００〜２００℃で乾燥させ、銅箔表面上にバンイダを乾燥固化させたもの（以下、バインダ塗布銅箔と称する）を作製した。
ＪＩＳ Ｈ ８６０２に準拠して、前記バインダ塗布銅箔のバインダ膜にカッターで２５個（１ｍｍ角）のマス目（以下、碁盤目試験片と称する）を作る。
前記碁盤目試験片にセロハンテープを貼り、セロハンテープを引き剥がしたときに、銅箔からバインダ膜が１マスも剥がれなかったものをＯＫ品、１マスでも剥がれたものをＮＧ品と判定する。
実施例１〜２４及び比較例１〜１２の圧延銅箔を用いて作製した碁盤目試験片１００個に対して前記の判定を行い、ＮＧ品０個の例を○、ＮＧ品１〜５個の例を△、ＮＧ品６個以上の例を×として評価した結果を図６及び図７に示す。
（２）圧延銅箔の強度
実施例１〜２４及び比較例１〜１２で得られた圧延銅箔を、幅１５ｍｍ、長さ２００ｍｍの試験片に切り出した後、該試験片に対して引張試験を行い、ＡＳＴＭ Ｅ−３４５に準拠して圧延平行方向の強度を測定した結果を図６及び図７に示す。
（３）圧延銅箔の導電率
実施例１〜２４及び比較例１〜１２で得られた圧延銅箔を、幅１５ｍｍ、長さ２００ｍｍの試験片に切り出した後、該試験片の電気抵抗を四端子測定法により測定し、導電率を算出した結果を図６及び図７に示す。 (1) Cross cut test As a method for evaluating the adhesion to the resin, the following cross cut test was performed. On the rolled copper foils obtained in Examples 1 to 24 and Comparative Examples 1 to 12, a solvent-based binder resin in which polyvinylidene fluoride (PVdF) was uniformly dissolved in an n-methylpyrrolidone (NMP) solvent as a binder resin was applied. After that, it was dried at 100 to 200 ° C., and a vanider was dried and solidified on the surface of the copper foil (hereinafter referred to as binder-coated copper foil).
In accordance with JIS H 8602, 25 (1 mm square) squares (hereinafter referred to as cross-cut test pieces) are made on the binder film of the binder-coated copper foil with a cutter.
When the cellophane tape is applied to the cross-cut test piece and the cellophane tape is peeled off, the one in which the binder film is not peeled off from the copper foil is judged as an OK product, and the one peeled off even in one square is judged as an NG product.
The above determination is performed on 100 cross-cut specimens prepared using the rolled copper foils of Examples 1 to 24 and Comparative Examples 1 to 12, and examples of 0 NG products are ◯ and 1 to 5 NG products. 6 and 7 show the results of evaluation with Δ as an example and X as an example when 6 or more NG products are used.
(2) Strength of rolled copper foil After the rolled copper foil obtained in Examples 1 to 24 and Comparative Examples 1 to 12 was cut into a test piece having a width of 15 mm and a length of 200 mm, a tensile test was performed on the test piece. 6 and 7 show the results of measuring the strength in the rolling parallel direction in accordance with ASTM E-345.
(3) Conductivity of rolled copper foil After cutting the rolled copper foil obtained in Examples 1 to 24 and Comparative Examples 1 to 12 into a test piece having a width of 15 mm and a length of 200 mm, the electrical resistance of the test piece was measured. FIG. 6 and FIG. 7 show the results of measurement by the four-terminal measurement method and calculation of the conductivity.

図６及び図７に示す実施例１〜２４から分かるように、本発明は原子間距離の変化量が−０．００２ｐｍ以下になるような添加元素Ａ、又は添加元素Ａと添加元素Ｂとを銅合金に含有させることによって、銅箔表面の粗化処理を行わないでも樹脂との密着性が良好となる。さらに、原子間距離の変化量が−０．００７ｐｍ以下において、樹脂との密着性が大幅に向上する（実施例１〜３、５〜１６、１８〜２３）。それに対して、図７の比較例１〜２に示すように、原子間距離の変化量が０．００以上で０．００２未満の範囲では、負の値であっても樹脂との密着性が向上しない。さらに、原子間距離が正の値であるような添加元素群の場合は、樹脂との密着性を得ることができない（図７の比較例４〜１２）。   As can be seen from Examples 1 to 24 shown in FIG. 6 and FIG. 7, in the present invention, the additive element A, or the additive element A and the additive element B such that the change in the interatomic distance is −0.002 pm or less. By making it contain in a copper alloy, adhesiveness with resin becomes favorable, even if it does not roughen the copper foil surface. Furthermore, when the amount of change in the interatomic distance is −0.007 pm or less, the adhesion with the resin is greatly improved (Examples 1 to 3, 5 to 16, and 18 to 23). On the other hand, as shown in Comparative Examples 1 and 2 in FIG. 7, in the range where the amount of change in the interatomic distance is 0.00 or more and less than 0.002, the adhesion to the resin is low even if it is a negative value. Does not improve. Furthermore, in the case of an additive element group in which the interatomic distance is a positive value, adhesion with the resin cannot be obtained (Comparative Examples 4 to 12 in FIG. 7).

本発明は、樹脂との密着性を向上できるだけではなく、添加元素Ａ又は添加元素Ａと添加元素Ｂとを微量含有することよって、圧延銅箔として比較的高い強度と導電率を有する。それに対して、銅合金中の添加元素の含有量が１．０重量％を超えると、導電率の低下が顕著になる（図７の比較例３）。そのため、比較例３の圧延銅箔は、リチウムイオン二次電池としての満足できる容量を得ることができず、集電体用として使用することができない。また、銅合金中の添加元素の含有量が０．５重量％を超えると、導電率の低下が大きくなっており（図６の実施例１３、１６）、高出力・高容量化が要求される電動バイクや電気自動車のモータ用電源等の用途への適用が制約される。   The present invention not only improves the adhesion to the resin, but also has a relatively high strength and electrical conductivity as a rolled copper foil by containing a small amount of additive element A or additive element A and additive element B. On the other hand, when the content of the additive element in the copper alloy exceeds 1.0% by weight, the decrease in conductivity becomes significant (Comparative Example 3 in FIG. 7). Therefore, the rolled copper foil of Comparative Example 3 cannot obtain a satisfactory capacity as a lithium ion secondary battery and cannot be used for a current collector. Moreover, when the content of the additive element in the copper alloy exceeds 0.5% by weight, the decrease in the conductivity is large (Examples 13 and 16 in FIG. 6), and high output and high capacity are required. Application to applications such as electric motors for electric motorcycles and electric motors for electric vehicles is limited.

本発明は、樹脂との密着性の向上という目的を達成するために、添加元素として添加元素Ａ群のどれかを含有する必要がある。添加元素Ａ群に加えて、さらにＣｕより原子半径が大きな添加元素Ｂ群を、原子間距離の変化量が−０．００２ｐｍ以下になるように含有させる場合に、樹脂との密着性の向上だけではなく、強度及び導電率の少なくともどちらかの特性を向上することができることが分かる（実施例１と実施例１８との対比、実施例６と実施例１７、１９、２２との対比、実施例７と実施例２１との対比を参照）。添加元素Ｂを併用する場合に、添加元素Ａだけのときと比べて別の特性の低下がみられることもあるが、その低下は小さく、集電体としての特性に大きな影響を及ぼさない。したがって、各特性を向上させる際に優先すべき特性に応じて、圧延銅箔中に含有する添加元素の組合せを自由に選択でき、銅合金組成の幅が広がる。さらに、添加元素のコストや入手のし易さ等についても考慮して添加元素を選択すれば、最終的に得られるリチウムイオン二次電池の低コスト化に対して大きく寄与できる。   In order to achieve the object of improving the adhesion to the resin, the present invention needs to contain any one of the additive element group A as an additive element. In addition to the additive element A group, when the additive element group B having a larger atomic radius than Cu is contained so that the change in the interatomic distance is -0.002 pm or less, only the adhesion to the resin is improved. However, it can be seen that at least one of strength and conductivity can be improved (contrast between Example 1 and Example 18, comparison between Example 6 and Examples 17, 19, and 22, and Example 7 and Example 21 comparison). When the additive element B is used in combination, there may be a decrease in other characteristics as compared with the case of the additive element A alone, but the decrease is small and does not significantly affect the characteristics of the current collector. Therefore, the combination of additive elements contained in the rolled copper foil can be freely selected according to the characteristics to be prioritized when improving each characteristic, and the width of the copper alloy composition is widened. Furthermore, if the additive element is selected in consideration of the cost and availability of the additive element, it can greatly contribute to the cost reduction of the finally obtained lithium ion secondary battery.

図６及び図７に示す実施例１〜２４は、樹脂バインダとして具体的にポリフッ化ビニリデン（ＰＶｄＦ）を使用した時の評価結果であるが、本発明ではそれ以外の樹脂バインダ、例えば、スチレンーブタジエンゴム（ＳＢＲ）の水系バインダを使用した場合でも、実施例１〜２１と同じ評価結果が得られることを確認している。ここで、スチレンーブタジエンゴム（ＳＢＲ）の水系バインダは、圧延銅箔の上に塗布した後、１００〜２００℃で乾燥させ、銅箔表面上にバンイダを乾燥固化させたものを評価用の試料として作製した。   Examples 1 to 24 shown in FIGS. 6 and 7 are evaluation results when polyvinylidene fluoride (PVdF) is specifically used as a resin binder. In the present invention, other resin binders such as styrene are used. Even when a water-based binder of butadiene rubber (SBR) is used, it has been confirmed that the same evaluation results as in Examples 1 to 21 can be obtained. Here, a water-based binder of styrene-butadiene rubber (SBR) was applied on a rolled copper foil, dried at 100 to 200 ° C., and a sample obtained by drying and solidifying the vanida on the copper foil surface. As produced.

本発明によれば、Ｃｕを主成分と銅合金において、原子間距離の変化量が−０．００２ｐｍ、好ましくは−０．００７ｐｍ以下となるように添加元素を含有させるとともに、添加元素の含有量を銅合金組成の総量を１００重量部としたときに１．０重量％、好ましくは０．５重量％以下にすることにより、高強度、高い熱的安定性、高導電率及び良好な加工性を有するだけではなく、表面粗化処理を施さずに負極活物質層に含まれる樹脂との密着性の高い圧延銅箔及び該圧延銅箔を用いたリチウムイオン二次電池負極を得ることができる。さらに、本発明の銅箔は、リチウムイオン二次電池だけではなく、同じ様な特性が要求される他の二次電池集電体用銅箔としても適用が可能であり、有用性が極めて高い。   According to the present invention, in the main component of Cu and the copper alloy, the additive element is added so that the change in the interatomic distance is −0.002 pm, preferably −0.007 pm or less, and the content of the additive element When the total amount of the copper alloy composition is 100 parts by weight, it is 1.0% by weight, preferably 0.5% by weight or less, so that high strength, high thermal stability, high conductivity, and good workability are achieved. It is possible to obtain a rolled copper foil having high adhesion to the resin contained in the negative electrode active material layer and a lithium ion secondary battery negative electrode using the rolled copper foil without performing surface roughening treatment. . Furthermore, the copper foil of the present invention can be applied not only to lithium ion secondary batteries, but also to other secondary battery current collector copper foils that require similar characteristics, and is extremely useful. .

Claims (9)

Ｃｕを主成分とし、Ｃｕより原子半径が小さな元素の１種又は２種以上からなる添加元素Ａと不可避不純物とを含有する銅合金組成を有し、（前記添加元素Ａを構成する各添加元素とＣｕとの原子半径の差）×（各添加元素の原子％）の総和を添加元素Ａによる原子間距離の変化量としたときに、該原子間距離の変化量が−０．００２ピコメーター（ｐｍ）以下であり、かつ前記添加元素Ａの総量が前記銅合金組成の総量を１００重量部としたときに１．０重量％以下であることを特徴とするリチウムイオン二次電池集電体用圧延銅箔。   It has a copper alloy composition containing an additive element A composed of one or two or more elements having an atomic radius smaller than that of Cu and an unavoidable impurity (each additive element constituting the additive element A) Difference between atomic radii of Cu and Cu) × (atomic% of each additive element) is defined as the amount of change in interatomic distance due to additive element A, the amount of change in interatomic distance is −0.002 picometer (Pm) or less, and the total amount of the additive element A is 1.0% by weight or less when the total amount of the copper alloy composition is 100 parts by weight. Rolled copper foil. 前記添加元素Ａは、Ｂ、Ｂｅ、Ｃｏ、Ｃｒ、Ｆｅ、Ｇａ、Ｇｅ、Ｍｎ、Ｎｉ、Ｐ、Ｓ及びＳｉからなる元素群の中から選ばれる元素の１種又は２種以上（ただし、ＦｅとＰの２種類からなる添加元素は除く）であることを特徴とする請求項１に記載のリチウムイオン二次電池集電体用圧延銅箔。   The additive element A is one or more elements selected from the element group consisting of B, Be, Co, Cr, Fe, Ga, Ge, Mn, Ni, P, S and Si (provided that Fe The rolled copper foil for a lithium ion secondary battery current collector according to claim 1, wherein the additive element consisting of two types of P and P is excluded. 前記添加元素Ａの総量が前記銅合金組成の総量を１００重量部としたときに０．５重量％以下であることを特徴とする請求項１又は２に記載のリチウムイオン二次電池集電体用圧延銅箔。   3. The lithium ion secondary battery current collector according to claim 1, wherein the total amount of the additive element A is 0.5 wt% or less when the total amount of the copper alloy composition is 100 parts by weight. Rolled copper foil. 前記添加元素Ａに加えて、さらにＣｕより原子半径が大きな元素の１種又は２種以上からなる添加元素Ｂを含有する請求項１〜３の何れかに記載のリチウムイオン二次電池集電体用圧延銅箔。   The lithium ion secondary battery current collector according to any one of claims 1 to 3, further comprising an additive element B made of one or more elements having an atomic radius larger than Cu, in addition to the additive element A. Rolled copper foil. 前記添加元素Ｂは、Ａｇ、Ａｌ、Ｉｎ、Ｍｇ、Ｓｎ、Ｔｉ、Ｚｎ及びＺｒからなる元素群の中から選ばれる元素の１種又は２種以上であることを特徴とする請求項１〜４の何れかに記載のリチウムイオン二次電池集電体用圧延銅箔。   The additive element B is one or more elements selected from an element group consisting of Ag, Al, In, Mg, Sn, Ti, Zn, and Zr. A rolled copper foil for a lithium ion secondary battery current collector according to any one of the above. 前記原子間距離の変化量が−０．００７ピコメーター（ｐｍ）以下となる請求項１〜５の何れかに記載のリチウムイオン二次電池集電体用圧延銅箔。   The rolled copper foil for a lithium ion secondary battery current collector according to any one of claims 1 to 5, wherein a change amount of the interatomic distance is -0.007 picometer (pm) or less. 前記の添加元素Ａと添加元素Ｂとの総量が、銅合金組成を１００重量部としたときに０．５重量％以下であることを特徴とする請求項４〜６の何れかに記載のリチウムイオン二次電池集電体用圧延銅箔。   7. The lithium according to claim 4, wherein the total amount of the additive element A and the additive element B is 0.5% by weight or less when the copper alloy composition is 100 parts by weight. Rolled copper foil for an ion secondary battery current collector. ２０μｍ以下の厚さを有する請求項１〜７の何れかに記載のリチウムイオン二次電池集電体用圧延銅箔。   The rolled copper foil for a lithium ion secondary battery current collector according to any one of claims 1 to 7, having a thickness of 20 µm or less. 請求項１〜８の何れかに記載のリチウムイオン二次電池集電体用圧延銅箔を用いて、該リチウムイオン二次電池集電体用圧延銅箔の表面祖化処理を行わないで、前記圧延銅箔の表面上にバインダ樹脂を含む負極活物質層を形成したことを特徴とするリチウムイオン二次電池負極。   Using the rolled copper foil for a lithium ion secondary battery current collector according to any one of claims 1 to 8, without subjecting the surface of the rolled copper foil for a lithium ion secondary battery current collector, A negative electrode for a lithium ion secondary battery, wherein a negative electrode active material layer containing a binder resin is formed on the surface of the rolled copper foil.
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