JP2020074261A - Collector for power storage device, manufacturing method therefor, and coating liquid used for manufacturing the same - Google Patents

Collector for power storage device, manufacturing method therefor, and coating liquid used for manufacturing the same Download PDF

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JP2020074261A
JP2020074261A JP2017042873A JP2017042873A JP2020074261A JP 2020074261 A JP2020074261 A JP 2020074261A JP 2017042873 A JP2017042873 A JP 2017042873A JP 2017042873 A JP2017042873 A JP 2017042873A JP 2020074261 A JP2020074261 A JP 2020074261A
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polymer
vinyl
fluorine
storage device
mass
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彬史 武田
Akifumi Takeda
彬史 武田
中村　武志
Takeshi Nakamura
武志 中村
仁 横内
Hitoshi Yokouchi
仁 横内
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Resonac Holdings Corp
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Showa Denko KK
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Priority to JP2017042873A priority Critical patent/JP2020074261A/en
Priority to PCT/JP2018/008486 priority patent/WO2018164094A1/en
Priority to TW107107661A priority patent/TW201843870A/en
Publication of JP2020074261A publication Critical patent/JP2020074261A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/04—Hybrid capacitors
    • H01G11/06—Hybrid capacitors with one of the electrodes allowing ions to be reversibly doped thereinto, e.g. lithium ion capacitors [LIC]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/66—Current collectors
    • H01G11/68—Current collectors characterised by their material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/66—Current collectors
    • H01G11/70—Current collectors characterised by their structure
    • 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
    • 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

Abstract

To provide a collector for a power storage device for obtaining the low-resistance power storage device by supplying coating liquid in which dispersibility of a powder-state carbon material such as carbon fine particles is improved, and a manufacturing method therefor.SOLUTION: The present invention relates to a collector for a power storage device in which a coating layer is formed at one side or both the sides of a sheet-like conductive substrate. The coating layer contains a powder-like carbon material, a polymer containing vinylidene fluoride as a monomer unit, and a fluorine non-containing vinyl-based polymer. The fluorine non-containing vinyl-based polymer is a homopolymer defining as a monomer unit one selected from among the group of N-vinyl acetamide and N-vinyl acetamide derivative, the group of vinyl alcohol and vinyl alcohol derivative, the group of vinyl pyrrolidone and vinyl pyrrolidone derivative and the group of acetic acid vinyl and acetic acid vinyl derivative, or a copolymer containing one or more selected from among the groups as a monomer unit, and a content of the fluorine non-containing vinyl-based polymers in the coating layer ranges from 0.099 to 5.0 mass%.SELECTED DRAWING: None

Description

本発明は、蓄電デバイス用集電体、その製造方法、およびその製造に用いる塗工液に関する。より詳細には、金属箔の表面に粉体状炭素材料を含む樹脂層を備えた蓄電デバイス用集電体、その製造方法、およびその製造に用いる塗工液に関する。
なお、本発明において蓄電デバイスとは、蓄電池ではリチウムイオン二次電池、電気化学キャパシタでは電気二重層キャパシタおよびリチウムイオンキャパシタのことを言う。 The present invention relates to a current collector for an electricity storage device, a method for manufacturing the current collector, and a coating liquid used for manufacturing the current collector. More specifically, the present invention relates to a current collector for an electricity storage device having a resin layer containing a powdery carbon material on the surface of a metal foil, a method for producing the current collector, and a coating liquid used for the production.
In the present invention, the electricity storage device refers to a lithium ion secondary battery in a storage battery, an electric double layer capacitor and a lithium ion capacitor in an electrochemical capacitor.

近年、リチウムイオン二次電池、電気二重層キャパシタ、レドックスフロー電池等は、蓄電デバイスとして高い注目を集めている。リチウムイオン二次電池は、小型化、軽量化の面からノート型パソコン、携帯電話、電動工具、電子・通信機器の電源等として使用されている。最近では、リチウムイオン二次電池は、環境車両への適用の観点から電気自動車やハイブリッド自動車にも使用されている。また電気二重層キャパシタも、その著しく高い蓄電量からバッテリーの代替の可能性を持ち、バックアップ電源、自動車のアイドリングストップシステム、ＥＳＳなどの大型蓄電システム等、高い注目を集めている。さらに、レドックスフロー電池は、高いサイクル寿命の面から１０００ｋＷ級の大型電力用設備として実用化が進められている。   In recent years, lithium ion secondary batteries, electric double layer capacitors, redox flow batteries and the like have been attracting a lot of attention as power storage devices. BACKGROUND ART Lithium ion secondary batteries are used as power sources for notebook type personal computers, mobile phones, electric tools, electronic / communication devices, etc. in terms of size reduction and weight reduction. Recently, lithium-ion secondary batteries have been used in electric vehicles and hybrid vehicles from the viewpoint of application to environmental vehicles. In addition, electric double layer capacitors have the possibility of substituting for batteries due to their remarkably high storage capacity, and have attracted a great deal of attention as backup power supplies, automobile idling stop systems, large storage systems such as ESS, and the like. Further, the redox flow battery is being put into practical use as a large-scale electric power facility of 1000 kW class in terms of high cycle life.

リチウムイオン二次電池、電気二重層キャパシタおよびレドックスフロー電池は、それぞれ一部に類似した構成を有している。これらに類似した構成の一つとして電極が挙げられる。電極の低抵抗化は、リチウムイオン二次電池、電気二重層キャパシタおよびレドックスフロー電池のそれぞれについて共通した課題であり、種々の検討が進められている。   The lithium-ion secondary battery, the electric double layer capacitor, and the redox flow battery each have a partially similar configuration. An electrode is mentioned as one of the structures similar to these. Reducing the resistance of the electrodes is a common problem for each of the lithium ion secondary battery, the electric double layer capacitor, and the redox flow battery, and various studies have been made.

例えば、リチウムイオン二次電池は、コバルト酸リチウム等の金属酸化物を正極活物質とした正極と、黒鉛等の炭素材料を負極活物質とした負極と、カーボネート類を溶剤とした電解液とからなる。リチウムイオン二次電池は、リチウムイオンが正極と負極との間を移動することにより、充放電が行われる。
正極は、正極活物質とバインダーを含むスラリーをアルミニウム箔などの正極集電体表面に塗布し、乾燥させた後、適当な大きさに切断することにより得られる。負極は、負極活物質とバインダーを含むスラリーを銅箔などの負極集電体表面に塗布し、乾燥させた後、適当な大きさに切断することにより得られる。正極には、バインダーとしてポリフッ化ビニリデン（ＰＶＤＦ）、ポリテトラフルオロエチレン（ＰＴＦＥ）等を用いた有機溶剤系のスラリーを用いることが一般的であり、負極には、バインダーとしてスチレンブタジエンラバー（ＳＢＲ）、アクリル系樹脂等を用いた水系のスラリーを用いることが一般的である。 For example, a lithium ion secondary battery includes a positive electrode using a metal oxide such as lithium cobalt oxide as a positive electrode active material, a negative electrode using a carbon material such as graphite as a negative electrode active material, and an electrolytic solution using a carbonate as a solvent. Become. The lithium ion secondary battery is charged and discharged by moving lithium ions between the positive electrode and the negative electrode.
The positive electrode is obtained by applying a slurry containing a positive electrode active material and a binder on the surface of a positive electrode current collector such as an aluminum foil, drying it, and then cutting it into a suitable size. The negative electrode is obtained by applying a slurry containing a negative electrode active material and a binder on the surface of a negative electrode current collector such as a copper foil, drying the slurry, and then cutting the slurry into an appropriate size. It is common to use an organic solvent-based slurry that uses polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), or the like as a binder for the positive electrode, and styrene-butadiene rubber (SBR) as a binder for the negative electrode. It is common to use an aqueous slurry using an acrylic resin or the like.

ところで、近年、蓄電デバイスの高容量化の要望のもと、高電圧用活物質を用いた高電圧化を試みることが行われている。例えば、リチウムイオン二次電池ではニッケルの比率が高い正極活物質を用いて、４．２Ｖ以上の電圧で充電を行い、高容量化を実現しようとする試みなどが行われている。さらに蓄電デバイスの低抵抗化、長寿命化を達成する手段として、電極用集電体として用いられるアルミニウム箔等に炭素微粒子をバインダー樹脂と共にコーティングしたカーボンコート箔を用いて、電極と集電体の界面抵抗を低減し、蓄電デバイス自体の抵抗を低減化することが行われている。しかしながら、高電圧化すると、一般的なカーボンコート箔に使用するバインダー樹脂（アクリル系樹脂、多糖類系樹脂等）の耐電圧を超えるため、これらが酸化分解し、蓄電デバイスの機能劣化を引き起こすという問題がある。機能劣化とは電極と集電体の界面抵抗が高くなり、また電極と集電体の間の密着性が低くなることである。これにより、蓄電デバイスの正常な充放電が行うことができなくなり、電池の内部抵抗の上昇、容量の低下、短寿命化など二次電池の重要な性能指標である特性すべてに影響を与えることとなる。   By the way, in recent years, with the demand for higher capacity of power storage devices, attempts have been made to increase the voltage using active materials for high voltage. For example, in a lithium-ion secondary battery, an attempt has been made to achieve high capacity by using a positive electrode active material having a high nickel ratio and charging at a voltage of 4.2 V or higher. Further, as a means for achieving low resistance and long life of the electricity storage device, a carbon-coated foil obtained by coating fine carbon particles with a binder resin on an aluminum foil or the like used as a current collector for electrodes is used. It has been attempted to reduce the interface resistance and the resistance of the electricity storage device itself. However, when the voltage is increased, the withstand voltage of the binder resin (acrylic resin, polysaccharide resin, etc.) used for general carbon coated foils is exceeded, so these are oxidized and decomposed, causing functional deterioration of the electricity storage device. There's a problem. Functional deterioration means that the interface resistance between the electrode and the current collector increases and the adhesion between the electrode and the current collector decreases. As a result, normal charging / discharging of the electricity storage device cannot be performed, and all characteristics that are important performance indicators of the secondary battery, such as increased internal resistance of the battery, decreased capacity, and shortened life, are affected. Become.

このような問題を解決する手段として、蓄電デバイス用集電体のカーボンコート箔に使用するバインダー樹脂として、耐電圧が高いＰＶＤＦを適用することが考えられる。例えば、特許文献１〜４にはＰＶＤＦがバインダーとして記載されており、これらの蓄電デバイスでは高電圧化による高容量化の向上が期待される。   As a means for solving such a problem, it is conceivable to apply PVDF having a high withstand voltage as the binder resin used for the carbon-coated foil of the current collector for the electricity storage device. For example, in Patent Documents 1 to 4, PVDF is described as a binder, and in these electric storage devices, improvement in high capacity due to high voltage is expected.

特許文献１には、導電性基材の少なくとも片面に導電性を有する樹脂層を有する集電体で、樹脂層がフッ素系樹脂と導電性粒子を含み、かつ厚さが０．３〜２０μｍである集電体が開示されている。フッ素系樹脂としてはＰＶＤＦとアクリル酸変性ＰＶＤＦが好ましいことが示されている。この集電体を用いたリチウムイオン電池などにはシャットダウン機能と高いハイレート特性が付与できることが記載されている。
特許文献２には、集電体と電極合剤層の間に導電層が介在しており、導電層は、導電材と、結着剤としてのＰＶＤＦとを含み、導電層は、核磁気共鳴スペクトルに基づくＰＶＤＦのα晶とβ晶との質量比（α晶／β晶）が０．３５〜０．５６であることが開示されている。この構成により、過充電等による温度上昇時に、電池の内部抵抗を高めて電池の過熱を抑えることができることが記載されている。
特許文献３には、電極活物質層と集電体との間に、導電性粒子と熱可塑性ポリマーとを含む導電性中間層が介在しており、熱可塑性ポリマーは数平均分子量が６３万以上１００万未満であり、熱可塑性ポリマーとしてＰＶＤＦが好ましいことが開示されている。この構成により、二次電池用電極における導電性中間層の安定性およびサイクル特性を高め、また、導電性中間層が担うシャットダウン効果を良好に発揮することが記載されている。
特許文献４には、正極集電体の表面に第１結着剤が活物質中に含まれてなる正極活物質層が形成された正極と、負極集電体の表面に前記第１結着剤と同一又は異なる第２結着剤が活物質中に含まれてなる負極活物質層が形成された負極とを備えたリチウムイオンポリマー二次電池において、正極集電体と正極活物質層との間に第１密着層を有し、負極集電体と負極活物質層との間に第２密着層を有し、第１および第２密着層が第３結着剤と導電性物質の双方をそれぞれ含み、第３結着剤が、第１結着剤又は第２結着剤を変性物質により変性させた高分子化合物であるリチウムイオンポリマー二次電池を示している。第１結着剤および第２結着剤としてＰＶＤＦが一例として挙げられており、第１密着層または第２密着層に黒鉛と変性ＰＶＤＦと０．１〜２０質量％の分散剤を含むことを示しており、分散剤は酸性高分子系分散剤、塩基性高分子系分散剤又は中性高分子系分散剤等を挙げている。これにより集電体と活物質層との密着性が高くなる、電解液に対して溶解されることなく長期保存性やサイクル特性に優れる、電池内部でフッ酸などが発生した場合でも密着層が保護層となり集電体の腐食を抑制できる、などが開示されている。 Patent Document 1 discloses a current collector having a conductive resin layer on at least one surface of a conductive substrate, the resin layer containing a fluororesin and conductive particles, and having a thickness of 0.3 to 20 μm. A current collector is disclosed. It has been shown that PVDF and acrylic acid-modified PVDF are preferable as the fluorine-based resin. It is described that a shutdown function and high high rate characteristics can be imparted to a lithium ion battery or the like using this current collector.
In Patent Document 2, a conductive layer is interposed between a current collector and an electrode mixture layer, the conductive layer contains a conductive material and PVDF as a binder, and the conductive layer has a nuclear magnetic resonance. It is disclosed that the mass ratio (α crystal / β crystal) of PVDF α crystal and β crystal based on the spectrum is 0.35 to 0.56. It is described that with this configuration, when the temperature rises due to overcharge or the like, the internal resistance of the battery can be increased and the battery can be prevented from overheating.
In Patent Document 3, a conductive intermediate layer containing conductive particles and a thermoplastic polymer is interposed between an electrode active material layer and a current collector, and the thermoplastic polymer has a number average molecular weight of 630,000 or more. It is disclosed that it is less than one million and PVDF is preferable as the thermoplastic polymer. It is described that with this configuration, the stability and cycle characteristics of the conductive intermediate layer in the secondary battery electrode are enhanced, and the shutdown effect of the conductive intermediate layer is excellently exhibited.
Patent Document 4 discloses a positive electrode in which a positive electrode active material layer in which a first binder is contained in an active material is formed on the surface of a positive electrode current collector, and the first binding agent on the surface of a negative electrode current collector. In a lithium ion polymer secondary battery including a negative electrode in which a negative electrode active material layer in which a second binder, which is the same as or different from the agent, is included in the active material, a positive electrode current collector and a positive electrode active material layer are provided. And a second adhesive layer between the negative electrode current collector and the negative electrode active material layer, and the first and second adhesive layers include a third binder and a conductive material. It shows a lithium ion polymer secondary battery including both of them and the third binder being a polymer compound obtained by modifying the first binder or the second binder with a modifying substance. PVDF is mentioned as an example of the first binder and the second binder, and the first adhesive layer or the second adhesive layer contains graphite, modified PVDF, and 0.1 to 20% by mass of a dispersant. As the dispersant, an acidic polymer dispersant, a basic polymer dispersant, a neutral polymer dispersant and the like are listed. As a result, the adhesion between the current collector and the active material layer increases, the long-term storage stability without being dissolved in the electrolyte and the cycle characteristics are excellent, and the adhesion layer is formed even when hydrofluoric acid or the like is generated inside the battery. It is disclosed that it serves as a protective layer and can suppress corrosion of the current collector.

国際公開第ＷＯ２０１３／１５１０４６号International Publication No. WO2013 / 151046 特許第５５５３１６５号公報Patent No. 5553165 特許第５５７８３７０号公報Patent No. 5578370 特許第３９８２２２１号公報Japanese Patent No. 3982221

ＰＶＤＦはリチウムイオン二次電池などの電極に使用されるバインダーとして一般的に知られているが、導電助剤としての炭素微粒子とＰＶＤＦとを含むスラリー中の炭素微粒子の分散性は非常に悪く、特にカーボンコート箔のように使用する炭素微粒子の粒子径が小さい場合には顕著である。炭素微粒子の分散性が悪いと基材上に均一に塗布できず塗布ムラが発生し、導電性が悪い部分が発生するため好ましくない。また、グラビア印刷機で薄く均一に塗布しようとした場合に、スジ状の抜け（基材がスジ状に露出する部分）が発生したり、グラビア印刷版のセルが目詰まりすることがある。すなわちＰＶＤＦをバインダーとして適正にカーボンコート箔に適用するには多くの課題がある。
課題解決の一つとして、分散性を向上させるためには分散剤などの添加剤を添加することが効果的である。また添加量も重要であり、添加しすぎるとスラリーの粘度が上がり、添加量が少ないと分散性向上の効果が得られず、使用に当たっては詳細な検討が必要である。しかしながら、特許文献１には添加剤は記載されていない。特許文献２にはＰＶＤＦ以外にも任意の成分を含有し得る、と記載されており、例としてＰＶＤＦ以外のポリマーを挙げているが、その詳細は記載されていない。特許文献３には、導電性中間層の材料である導電性粒子と熱可塑性ポリマーとを溶媒中で混合する場合に、分散剤、増粘剤等の各種の添加物を必要に応じ混合することが記載されているが、詳細は記載されていない。特許文献４では分散剤として、酸性高分子系分散剤、塩基性高分子系分散剤又は中性高分子系分散剤等の記載はあるものの、具体的な詳細検討は行われていない。 PVDF is generally known as a binder used for electrodes such as lithium ion secondary batteries, but the dispersibility of carbon fine particles in a slurry containing carbon fine particles as a conductive aid and PVDF is very poor, This is particularly noticeable when the carbon fine particles used, such as carbon-coated foil, have a small particle size. If the dispersibility of the carbon fine particles is poor, it cannot be uniformly coated on the substrate, coating unevenness occurs, and portions having poor conductivity are generated, which is not preferable. Further, when it is attempted to apply thinly and uniformly with a gravure printing machine, streak-like voids (portions where the substrate is exposed in a streak-like shape) may occur, or the cells of the gravure printing plate may become clogged. That is, there are many problems in properly applying PVDF as a binder to a carbon-coated foil.
As one of the solutions to the problem, it is effective to add an additive such as a dispersant in order to improve the dispersibility. The addition amount is also important. If the addition amount is too large, the viscosity of the slurry increases, and if the addition amount is too small, the effect of improving the dispersibility cannot be obtained. Therefore, detailed examination is required before use. However, Patent Document 1 does not describe any additive. Patent Document 2 describes that any component other than PVDF may be contained, and a polymer other than PVDF is mentioned as an example, but details thereof are not described. In Patent Document 3, when the conductive particles, which are the material of the conductive intermediate layer, and the thermoplastic polymer are mixed in a solvent, various additives such as a dispersant and a thickener are mixed as necessary. , But not the details. Although Patent Document 4 describes an acidic polymer-based dispersant, a basic polymer-based dispersant, a neutral polymer-based dispersant, or the like as a dispersant, no specific detailed study has been conducted.

本発明は、導電性基材の片面または両面にカーボンコート層が形成された蓄電デバイス用集電体を製造するための塗工液で、液中の炭素微粒子等の粉体状炭素材料の分散性が向上した塗工液を供給すること、および低抵抗な蓄電デバイスを得るための蓄電デバイス用集電体とその製造方法を提供することを目的とする。   The present invention is a coating liquid for producing a current collector for an electricity storage device in which a carbon coating layer is formed on one side or both sides of a conductive base material, which is a dispersion of a powdery carbon material such as carbon fine particles in the liquid. It is an object of the present invention to supply a coating liquid having improved properties, and to provide a current collector for an electricity storage device for obtaining an electricity storage device having low resistance and a method for producing the same.

本発明者らは、上記目的を達成するために鋭意検討を重ねた結果、塗工液に特定のビニル系重合体を添加し、その添加量を特定の範囲とすることにより、塗工液における粉体状炭素材料の分散性が向上し、この塗工液を用いて製造した集電体を使用した蓄電デバイスの抵抗が低くなることを見出し、本発明を完成させるに至った。
即ち、本発明は、上記課題を解決するため、以下の手段を提供する。 The present inventors have conducted extensive studies to achieve the above object, as a result of adding a specific vinyl polymer to the coating liquid, and by setting the addition amount within a specific range, in the coating liquid. The inventors have found that the dispersibility of the powdery carbon material is improved and the resistance of an electricity storage device using a current collector produced by using this coating solution is lowered, and the present invention has been completed.
That is, the present invention provides the following means in order to solve the above problems.

［１］ シート状の導電性基材の片面または両面に被覆層が形成された蓄電デバイス用集電体であって、
前記被覆層は粉体状炭素材料、モノマ単位としてフッ化ビニリデンを含む重合体およびフッ素非含有ビニル系重合体を含み、
前記フッ素非含有ビニル系重合体は、Ｎ−ビニルアセトアミドおよびＮ−ビニルアセトアミド誘導体、ビニルアルコールおよびビニルアルコール誘導体、ビニルピロリドンおよびビニルピロリドン誘導体、ならびに酢酸ビニルおよび酢酸ビニル誘導体からなる群から選ばれる１種をモノマ単位とする単独重合体、または前記の群から選ばれる１種以上をモノマ単位として含む共重合体であり、
前記被覆層中の前記フッ素非含有ビニル系重合体の含有率が０．０９９〜５．０質量％であることを特徴とする蓄電デバイス用集電体。
［２］ 前記被覆層中の前記粉体状炭素材料の含有率が２０．０〜５０．０質量％である前記１に記載の蓄電デバイス用集電体。
［３］ 前記導電性基材一面当たりの前記被覆層の目付量が０．１〜５．０ｇ／ｍ２である前記１または２に記載の蓄電デバイス用集電体。
［４］ 前記１〜３のいずれか一項に記載の蓄電デバイス用集電体を備えたリチウムイオン二次電池用電極。
［５］ 前記１〜３のいずれか一項に記載の蓄電デバイス用集電体を備えたリチウムイオン二次電池。
［６］ 溶媒中に粉体状炭素材料、モノマ単位としてフッ化ビニリデンを含む重合体およびフッ素非含有ビニル系重合体が溶解または分散した塗工液を調製する工程、
前記調製した塗工液をシート状の導電性基材の片面または両面に塗布する工程、および
前記塗布した塗工液を乾燥させる工程を有し、
前記フッ素非含有ビニル系重合体は、Ｎ−ビニルアセトアミドおよびＮ−ビニルアセトアミド誘導体、ビニルアルコールおよびビニルアルコール誘導体、ビニルピロリドンおよびビニルピロリドン誘導体、ならびに酢酸ビニルおよび酢酸ビニル誘導体からなる群から選ばれる１種をモノマ単位とする単独重合体、または前記の群から選ばれる１種以上をモノマ単位として含む共重合体であり、
前記塗工液中の前記粉体状炭素材料、前記フッ化ビニリデンを含む重合体および前記フッ素非含有ビニル系重合体の合計の含有率が２〜１５質量％であり、
前記粉体状炭素材料、前記フッ化ビニリデンを含む重合体および前記フッ素非含有ビニル系重合体の合計質量に対する該フッ素非含有ビニル系重合体の質量割合が０．０９９〜５．０質量％であることを特徴とする蓄電デバイス用集電体の製造方法。
［７］ 前記溶媒が水またはＮ−メチル−２−ピロリドンである前記６に記載の蓄電デバイス用集電体の製造方法。
［８］ 溶媒中に粉体状炭素材料、モノマ単位としてフッ化ビニリデンを含む重合体およびフッ素非含有ビニル系重合体を含み、
前記フッ素非含有ビニル系重合体は、Ｎ−ビニルアセトアミドおよびＮ−ビニルアセトアミド誘導体、ビニルアルコールおよびビニルアルコール誘導体、ビニルピロリドンおよびビニルピロリドン誘導体、ならびに酢酸ビニルおよび酢酸ビニル誘導体からなる群から選ばれる１種をモノマ単位とする単独重合体、または前記の群から選ばれる１種以上をモノマ単位として含む共重合体であり、
前記塗工液中の前記粉体状炭素材料、前記フッ化ビニリデンを含む重合体および前記フッ素非含有ビニル系重合体の合計の含有率が２〜１５質量％であり、
前記粉体状炭素材料、前記フッ化ビニリデンを含む重合体および前記フッ素非含有ビニル系重合体の合計質量に対する該フッ素非含有ビニル系重合体の質量割合が０．０９９〜５．０質量％であることを特徴とする蓄電デバイス用集電体を製造するための塗工液。
［９］ 前記溶媒が水またはＮ−メチル−２−ピロリドンである前記８に記載の蓄電デバイス用集電体を製造するための塗工液。 [1] A current collector for an electricity storage device, in which a coating layer is formed on one or both sides of a sheet-shaped conductive substrate,
The coating layer contains a powdered carbon material, a polymer containing vinylidene fluoride as a monomer unit and a non-fluorine-containing vinyl polymer,
The fluorine-free vinyl polymer is one selected from the group consisting of N-vinylacetamide and N-vinylacetamide derivatives, vinyl alcohol and vinyl alcohol derivatives, vinylpyrrolidone and vinylpyrrolidone derivatives, and vinyl acetate and vinyl acetate derivatives. Is a homopolymer having a monomer unit, or a copolymer containing at least one selected from the above group as a monomer unit,
The current collector for an electricity storage device, wherein the content of the fluorine-free vinyl polymer in the coating layer is 0.099 to 5.0% by mass.
[2] The current collector for an electricity storage device according to the above 1, wherein the content of the powdery carbon material in the coating layer is 20.0 to 50.0 mass%.
[3] The current collector for an electricity storage device according to 1 or 2, wherein the basis weight of the coating layer per one surface of the conductive base material is 0.1 to 5.0 g / m 2 .
[4] An electrode for a lithium ion secondary battery, comprising the current collector for an electricity storage device according to any one of 1 to 3 above.
[5] A lithium-ion secondary battery including the current collector for an electricity storage device according to any one of 1 to 3 above.
[6] A step of preparing a coating liquid in which a powdery carbon material, a polymer containing vinylidene fluoride as a monomer unit, and a fluorine-free vinyl polymer are dissolved or dispersed in a solvent,
A step of applying the prepared coating liquid on one or both sides of a sheet-shaped conductive substrate, and a step of drying the applied coating liquid,
The fluorine-free vinyl polymer is one selected from the group consisting of N-vinylacetamide and N-vinylacetamide derivatives, vinyl alcohol and vinyl alcohol derivatives, vinylpyrrolidone and vinylpyrrolidone derivatives, and vinyl acetate and vinyl acetate derivatives. Is a homopolymer having a monomer unit, or a copolymer containing at least one selected from the above group as a monomer unit,
The total content of the powdery carbon material, the vinylidene fluoride-containing polymer and the fluorine-free vinyl polymer in the coating liquid is 2 to 15% by mass,
The mass ratio of the fluorine-free vinyl-based polymer to the total mass of the powdery carbon material, the vinylidene fluoride-containing polymer and the fluorine-free vinyl-based polymer is 0.099 to 5.0% by mass. A method for manufacturing a current collector for an electricity storage device, which is characterized by the following.
[7] The method for producing a current collector for an electricity storage device according to the above 6, wherein the solvent is water or N-methyl-2-pyrrolidone.
[8] A powdery carbon material, a polymer containing vinylidene fluoride as a monomer unit, and a fluorine-free vinyl polymer in a solvent,
The fluorine-free vinyl polymer is one selected from the group consisting of N-vinylacetamide and N-vinylacetamide derivatives, vinyl alcohol and vinyl alcohol derivatives, vinylpyrrolidone and vinylpyrrolidone derivatives, and vinyl acetate and vinyl acetate derivatives. Is a homopolymer having a monomer unit, or a copolymer containing at least one selected from the above group as a monomer unit,
The total content of the powdery carbon material, the vinylidene fluoride-containing polymer and the fluorine-free vinyl polymer in the coating liquid is 2 to 15% by mass,
The mass ratio of the fluorine-free vinyl polymer to the total mass of the powdery carbon material, the vinylidene fluoride-containing polymer and the fluorine-free vinyl polymer is 0.099 to 5.0% by mass. A coating liquid for producing a current collector for an electricity storage device, which is characterized by being present.
[9] The coating liquid for producing the current collector for an electricity storage device described in 8 above, wherein the solvent is water or N-methyl-2-pyrrolidone.

本発明に係る蓄電デバイス用集電体は、導電性基材の表面に、粉体状炭素材料、フッ化ビニリデンを含む重合体およびフッ素非含有ビニル系重合体を含む被覆層が形成された集電体であり、被覆層中のフッ素非含有ビニル系重合体の含有率が０．０９９〜５．０質量％の範囲である。また本発明に係る蓄電デバイス用集電体の被覆層形成用の塗工液は、塗工液に含まれる粉体状炭素材料、モノマ単位としてフッ化ビニリデンを含む重合体およびフッ素非含有ビニル系重合体の合計質量に対するフッ素非含有ビニル系重合体の質量割合が０．０９９〜５．０質量％である。このため、塗工液中の粉体状炭素材料の分散性が向上し、均一な塗工が可能になり、また、低抵抗な蓄電デバイスの提供が実現できる。   The current collector for an electricity storage device according to the present invention is a collector in which a coating layer containing a powdery carbon material, a polymer containing vinylidene fluoride and a non-fluorine-containing vinyl polymer is formed on the surface of a conductive substrate. The content of the fluorine-free vinyl polymer in the coating layer is 0.099 to 5.0% by mass. Further, the coating liquid for forming the coating layer of the current collector for the electricity storage device according to the present invention includes a powdery carbon material contained in the coating liquid, a polymer containing vinylidene fluoride as a monomer unit, and a fluorine-free vinyl-based material. The mass ratio of the fluorine-free vinyl polymer to the total mass of the polymer is 0.099 to 5.0 mass%. For this reason, the dispersibility of the powdery carbon material in the coating liquid is improved, uniform coating is possible, and a low-resistance electricity storage device can be provided.

本発明に係る蓄電デバイス用集電体の製造方法は、溶媒中に粉体状炭素材料、モノマ単位としてフッ化ビニリデンを含む重合体およびフッ素非含有ビニル系重合体が溶解または分散した塗工液を調製する工程と、調製した塗工液を導電性基材の片面または両面に塗布する工程と、塗布した塗工液を乾燥させる工程とを有する。この製造方法は、粉体状炭素材料、フッ化ビニリデンを含む重合体およびフッ素非含有ビニル系重合体が溶媒に溶解または分散した塗工液を用いるため、一般的な塗工方法が選択でき、集電体を容易に作製することができる。   The method for producing a current collector for an electricity storage device according to the present invention is a coating liquid in which a powdery carbon material, a polymer containing vinylidene fluoride as a monomer unit, and a fluorine-free vinyl polymer are dissolved or dispersed in a solvent. And a step of applying the prepared coating liquid on one or both surfaces of the conductive substrate, and a step of drying the applied coating liquid. This production method uses a coating liquid in which a powdery carbon material, a polymer containing vinylidene fluoride and a non-fluorine-containing vinyl polymer are dissolved or dispersed in a solvent, and thus a general coating method can be selected. The current collector can be easily manufactured.

実施例１−１の塗工液の分散性を観察した結果を示す写真。The photograph which shows the result of having observed the dispersibility of the coating liquid of Example 1-1. 実施例１−６の塗工液の分散性を観察した結果を示す写真。The photograph which shows the result of having observed the dispersibility of the coating liquid of Example 1-6. 比較例１−１の塗工液の分散性を観察した結果を示す写真。The photograph which shows the result of having observed the dispersibility of the coating liquid of Comparative Example 1-1. 実施例９のグラビアコート試験において、凝集物発生がなく塗工性の良好なグラビアロール部の外観を示す写真。In the gravure coat test of Example 9, a photograph showing the appearance of a gravure roll part having no coats and good coatability. 比較例９のグラビアコート試験において、凝集物発生により塗工性が悪いグラビアロール部の外観を示す写真。In the gravure coat test of Comparative Example 9, a photograph showing the appearance of a gravure roll portion having poor coatability due to the generation of aggregates.

以下、本発明に係る好ましい実施形態の蓄電デバイス用集電体、その製造方法、および集電体を製造するための塗工液について詳細に説明する。以下の説明において例示される材料、仕様等は一例であって、本発明はそれらに限定されるものではなく、その要旨を変更しない範囲で適宜変更して実施することが可能である。   Hereinafter, a current collector for an electricity storage device according to a preferred embodiment of the present invention, a method for manufacturing the current collector, and a coating liquid for manufacturing the current collector will be described in detail. The materials, specifications, and the like exemplified in the following description are examples, and the present invention is not limited to them, and can be appropriately modified and implemented without changing the gist thereof.

［蓄電デバイス用集電体］
本発明に係る好ましい実施形態の蓄電デバイス用集電体は、シート状の導電性基材の片面または両面に被覆層が形成されている。被覆層は、粉体状炭素材料、モノマ単位としてフッ化ビニリデンを含む重合体（以下、単に「フッ化ビニリデンを含む重合体」とも称する。）およびフッ素非含有ビニル系重合体を含む。 [Current collector for electricity storage device]
In a current collector for an electricity storage device according to a preferred embodiment of the present invention, a coating layer is formed on one surface or both surfaces of a sheet-shaped conductive base material. The coating layer contains a powdery carbon material, a polymer containing vinylidene fluoride as a monomer unit (hereinafter, also simply referred to as “polymer containing vinylidene fluoride”), and a non-fluorine-containing vinyl polymer.

（導電性基材）
蓄電デバイス用集電体のシート状の導電性基材の材質は金属であれば特に制限はなく、箔状の基材が好ましく用いられる。例えば、リチウムイオン二次電池の集電体では正極集電体にアルミニウム箔、負極集電体に銅箔が用いられる。
アルミニウム箔の材質には特に制限はなく、好ましくは純アルミニウム箔またはアルミニウムを９５質量％以上含むアルミニウム合金箔である。純アルミニウム箔の例としてはＡ１０８５材が挙げられ、アルミニウム合金箔の例としては、Ａ３００３材（Ｍｎ添加系）が挙げられる。
銅箔の材質には特に制限はなく、好ましくは表面が防錆処理をされた電解銅箔である。その他、蓄電デバイスに使用される基材を選ぶことができ、例えばニッケル箔、チタン箔、ステンレス箔などが挙げられる。
基材は厚さによって特に制限されないが、蓄電デバイスの小型化やハンドリング性などの観点から、通常は３μｍ〜１００μｍ厚のものが好ましく、ロールトゥーロール製法を行う場合は、５μｍ厚〜５０μｍ厚のものが好ましく用いられる。
基材の形状は、孔の開いていない箔でもよいし、二次元状のメッシュ箔、三次元状の網状の箔やパンチングメタル箔など、孔の開いている箔でもよい。
基材の表面は公知の表面処理が施されていてもよく、例えば、機械的表面加工、エッチング、化成処理、陽極酸化、ウォッシュプライマー、コロナ放電、グロー放電などの処理が挙げられる。 (Conductive substrate)
The material of the sheet-shaped conductive base material of the current collector for an electricity storage device is not particularly limited as long as it is a metal, and a foil-shaped base material is preferably used. For example, in a current collector of a lithium ion secondary battery, an aluminum foil is used for the positive electrode current collector and a copper foil is used for the negative electrode current collector.
The material of the aluminum foil is not particularly limited, and is preferably a pure aluminum foil or an aluminum alloy foil containing 95% by mass or more of aluminum. Examples of the pure aluminum foil include A1085 material, and examples of the aluminum alloy foil include A3003 material (Mn-added system).
The material of the copper foil is not particularly limited, and is preferably an electrolytic copper foil whose surface is rustproofed. In addition, the base material used for the electricity storage device can be selected, and examples thereof include nickel foil, titanium foil, and stainless steel foil.
The substrate is not particularly limited by the thickness, but from the viewpoint of downsizing and handling of the electricity storage device, it is usually preferably 3 μm to 100 μm thick, and when performing the roll-to-roll manufacturing method, it is 5 μm to 50 μm thick. Those are preferably used.
The shape of the substrate may be a non-perforated foil, or a perforated foil such as a two-dimensional mesh foil, a three-dimensional mesh foil or a punching metal foil.
The surface of the base material may be subjected to a known surface treatment, and examples thereof include mechanical surface treatment, etching, chemical conversion treatment, anodic oxidation, wash primer, corona discharge, glow discharge and the like.

（被覆層）
シート状の導電性基材の片面または両面には、粉体状炭素材料、フッ化ビニリデンを含む重合体およびフッ素非含有ビニル系重合体を含む被覆層が形成される。
被覆層の厚さは０．１μｍ以上１５．０μｍ以下が好ましく、０．２μｍ以上１０．０μｍ以下がより好ましく、０．３μｍ以上５．０μｍ以下がより一層好ましい。被覆層の厚さが０．１μｍ以上であれば、粉体状炭素材料により導電性基材と電極活物質の間の導電性が確保できるため好ましい。一方、厚さが１５．０μｍ以下であれば、層厚による電気抵抗の増加が大きくはならない点、さらに生産性の面からも好ましい。 (Coating layer)
A coating layer containing a powdery carbon material, a vinylidene fluoride-containing polymer and a fluorine-free vinyl-based polymer is formed on one or both sides of the sheet-like conductive base material.
The thickness of the coating layer is preferably 0.1 μm or more and 15.0 μm or less, more preferably 0.2 μm or more and 10.0 μm or less, and even more preferably 0.3 μm or more and 5.0 μm or less. When the thickness of the coating layer is 0.1 μm or more, it is preferable because the powdery carbon material can ensure the conductivity between the conductive base material and the electrode active material. On the other hand, when the thickness is 15.0 μm or less, the increase in the electric resistance due to the layer thickness does not increase, and it is preferable from the viewpoint of productivity.

導電性基材一面当たりの被覆層の目付量（単位面積当たりの塗布重量）は０．１〜５．０ｇ／ｍ２であることが好ましく、０．３〜３．０ｇ／ｍ２であることがより好ましい。被覆層の目付量が０．１ｇ／ｍ２以上であれば、粉体状炭素材料により導電性基材と電極活物質の間の導電性を確保できる。被覆層の目付量が５．０ｇ／ｍ２以下であれば、導電性基材に被覆層が形成されていない場合に較べて抵抗値を１／１０以下程度に低減させることができる点、さらに生産性の面からも好ましい。なお、導電性基材の両面に被覆層が形成される場合は、目付量は前記の約２倍となる。（表面と裏面で異なる目付量であってもよい。） Preferably the basis weight of the coating layer per conductive substrate one face (coating weight per unit area) is 0.1 to 5.0 g / m 2, it is 0.3 to 3.0 g / m 2 Is more preferable. When the basis weight of the coating layer is 0.1 g / m 2 or more, the powdery carbon material can ensure the conductivity between the conductive base material and the electrode active material. When the basis weight of the coating layer is 5.0 g / m 2 or less, the resistance value can be reduced to about 1/10 or less as compared with the case where the coating layer is not formed on the conductive base material. It is also preferable in terms of productivity. When the coating layers are formed on both surfaces of the conductive base material, the basis weight is about twice the above. (The basis weight may be different on the front surface and the back surface.)

（粉体状炭素材料）
粉体状炭素材料は、被覆層に導電性を付与する役目を果たすものであれば特に限定されないが、カーボンナノファイバー、カーボンナノチューブ等の炭素繊維、カーボンブラック、および黒鉛微粒子等の炭素微粒子が好ましい。カーボンブラックの例としては、アセチレンブラック、ファーネスブラック、ケッチェンブラックなどが挙げられる。特に、ＪＩＳ Ｋ １４６９：２００３に準拠して測定される粉体での電気抵抗が、１００％の圧粉体で１×１０−１Ω・ｃｍ以下のものが好ましく、必要に応じて上記のものを組み合わせて使用できる。 (Powdered carbon material)
The powdery carbon material is not particularly limited as long as it serves to impart conductivity to the coating layer, but carbon nanofibers, carbon fibers such as carbon nanotubes, carbon black, and carbon fine particles such as graphite fine particles are preferable. .. Examples of carbon black include acetylene black, furnace black and Ketjen black. In particular, it is preferable that the electric resistance of the powder measured according to JIS K 1469: 2003 is 1 × 10 −1 Ω · cm or less when the powder compact is 100%, and the above-mentioned ones are used as necessary. Can be used in combination.

粉体状炭素材料として用いられる炭素微粒子は、その一次粒子の粒子径に特に制限はないが、１０〜１００ｎｍが好ましい。炭素微粒子の一次粒子径は、電子顕微鏡を用いて１００〜１０００個の一次粒子径を計測し、これを算術平均することによって得られる。球状の場合は球換算径、不定形状の場合は最大長径を粒子径とする。
炭素微粒子の形状は特に制限はないが、粒子が数珠状に連鎖した導電パスが多く形成され、かつ、導電性基材上に均一に分散している状態が好ましい。その理由は、電子導電性の炭素微粒子は、電極の活物質と基材の間で電子の移動を分担しており、被覆層と活物質間の接触面積は大きい方が好ましいためである。さらに、炭素微粒子が凝集して島状になっている部分が少ない状態が好ましい。これは、凝集が少ない場合は被覆層の層厚が均一になり、蓄電デバイスの厚みをバラツキなく均一に設計できるためである。このためには、被覆層の表面の凹凸は表面粗さＲａが１μｍ以下であることが好ましい。 The particle size of the primary particles of the carbon fine particles used as the powdery carbon material is not particularly limited, but is preferably 10 to 100 nm. The primary particle diameter of the carbon fine particles is obtained by measuring 100 to 1000 primary particle diameters using an electron microscope and arithmetically averaging them. In the case of a sphere, the particle diameter is the sphere equivalent diameter, and in the case of an irregular shape, the maximum major axis is the particle diameter.
The shape of the carbon fine particles is not particularly limited, but it is preferable that a large number of conductive paths in which the particles are chained in a bead shape are formed and that the particles are uniformly dispersed on the conductive base material. The reason is that the electron-conductive carbon fine particles share the movement of electrons between the active material of the electrode and the base material, and the contact area between the coating layer and the active material is preferably large. Further, it is preferable that the carbon fine particles are agglomerated into a small number of islands. This is because when the amount of aggregation is small, the coating layer has a uniform thickness, and the power storage device can be designed to have a uniform thickness without variation. For this purpose, the surface roughness Ra of the unevenness of the surface of the coating layer is preferably 1 μm or less.

被覆層中の粉体状炭素材料の含有率は２０．０〜５０．０質量％であることが好ましく、２８．０〜５０．０質量％であることがより好ましく、４０．０〜５０．０質量％であることがより一層好ましい。
被覆層中の粉体状炭素材料の含有率が２０．０質量％以上であれば、十分な導電性を示すことができる。また、粉体状炭素材料の含有率が５０．０質量％以下であれば、バインダーが十分存在するため粉体状炭素材料同士および導電性基材と被覆層の密着性を維持することができる。 The content of the powdery carbon material in the coating layer is preferably 20.0 to 50.0% by mass, more preferably 28.0 to 50.0% by mass, and 40.0 to 50.%. It is even more preferably 0% by mass.
If the content of the powdery carbon material in the coating layer is 20.0 mass% or more, sufficient conductivity can be exhibited. Further, when the content of the powdery carbon material is 50.0% by mass or less, the adhesiveness between the powdery carbon materials and between the conductive base material and the coating layer can be maintained because the binder is sufficiently present. ..

（フッ化ビニリデンを含む重合体）
モノマ単位としてフッ化ビニリデンを含む重合体はバインダーとして被覆層に含まれる。フッ化ビニリデンを含む重合体の分子量や重合体のタイプは特に限定されない。モノマ単位としてフッ化ビニリデンを含む重合体は、フッ化ビニリデン（ＶＤＦ）の単独重合体であるポリフッ化ビニリデン（ＰＶＤＦ）、またはフッ化ビニリデンおよびこれと異なるフッ素化合物をモノマ単位とする共重合体である。このような共重合体としては、フッ化ビニリデンと以下に示すモノマ化合物、すなわちテトラフルオロエチレン（ＴＦＥ）、クロロトリフルオロエチレン（ＣＴＦＥ）、ヘキサフルオロプロピレン（ＨＦＰ）、ハイドロフルオロエーテル（ＨＦＥ）等との２元共重合体を挙げることができる。さらに、パーフルオロアルコキシアルカン（ＰＦＡ）との共重合体（実質的にはＶＤＦ−ＴＦＥ−パーフルオロアルキルビニルエーテルの三元共重合体）、エチレン−テトラフルオロエチレン共重合体（ＥＴＦＥ）との共重合体（実質的にはＶＤＦ−エチレン−ＴＦＥの三元共重合体）およびＶＤＦ−ＴＦＥ−ＨＦＰの三元共重合体等を挙げることができる。 (Polymer containing vinylidene fluoride)
A polymer containing vinylidene fluoride as a monomer unit is contained in the coating layer as a binder. The molecular weight of the polymer containing vinylidene fluoride and the type of the polymer are not particularly limited. A polymer containing vinylidene fluoride as a monomer unit is polyvinylidene fluoride (PVDF) which is a homopolymer of vinylidene fluoride (VDF), or a copolymer containing vinylidene fluoride and a different fluorine compound as a monomer unit. is there. As such a copolymer, vinylidene fluoride and the following monomer compounds, that is, tetrafluoroethylene (TFE), chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), hydrofluoroether (HFE), etc. The binary copolymer of Further, a copolymer with a perfluoroalkoxyalkane (PFA) (substantially a terpolymer of VDF-TFE-perfluoroalkyl vinyl ether), a copolymer with an ethylene-tetrafluoroethylene copolymer (ETFE) Examples thereof include a combination (substantially VDF-ethylene-TFE terpolymer) and a VDF-TFE-HFP terpolymer.

また、フッ化ビニリデンを含む重合体はその少なくとも一部が酸変性されているものを使用することが好ましい。酸変性とは、フッ化ビニリデンを含む重合体中の脱フッ酸した箇所の不飽和結合部に、新たに添加された酸が付加されることをいう。脱フッ酸は、フッ化ビニリデンを含む重合体を加熱することなどにより行うことができる。新たに添加する酸は、有機酸等の酸である。酸変性されたフッ化ビニリデンを含む重合体は付加された酸により金属箔への接着性が向上する。   Further, it is preferable to use a polymer containing vinylidene fluoride, at least a part of which is acid-modified. The acid modification means that the newly added acid is added to the unsaturated bond portion at the dehydrofluorinated portion in the polymer containing vinylidene fluoride. Hydrofluoric acid removal can be performed by heating a polymer containing vinylidene fluoride. The newly added acid is an acid such as an organic acid. The acid-modified vinylidene fluoride-containing polymer has improved adhesion to the metal foil due to the added acid.

酸変性させる酸および酸誘導体としては、アクリル酸、メタクリル酸、アクリル酸メチル、アクリル酸エチル、アクリル酸ブチル、メタクリル酸メチル、メタクリル酸エチル、メタクリル酸ブチル、マレイン酸モノメチル、マレイン酸モノエチル、無水マレイン酸、２−カルボキシエチルアクリレート、２−カルボキシエチルメタクリレート、アクリロイロキシエチルコハク酸、メタクリロイロキシエチルコハク酸、アクリロイロキシエチルフタル酸、メタクリロイロキシエチルフタル酸、トリフルオロアクリル酸、トリフルオロメチルアクリル酸、１，１−ビス（アクリロイルオキシメチル）エチルイソシアネート、２−アクリロイルオキシエチルイソシアネート、２−メタクリロイルオキシエチルイソシアネート等を用いることができる。中でも、ＰＶＤＦの一部をマレイン酸モノメチル、無水マレイン酸、アクリル酸メチル、メタクリル酸メチルで変性させたＰＶＤＦバインダーを好適に用いることができる。   Examples of the acid and the acid derivative to be acid-modified are acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, monomethyl maleate, monoethyl maleate, maleic anhydride. Acid, 2-carboxyethyl acrylate, 2-carboxyethyl methacrylate, acryloyloxyethyl succinic acid, methacryloyloxyethyl succinic acid, acryloyloxyethyl phthalic acid, methacryloyloxyethyl phthalic acid, trifluoroacrylic acid, trifluoromethyl Acrylic acid, 1,1-bis (acryloyloxymethyl) ethyl isocyanate, 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate and the like can be used.Above all, a PVDF binder obtained by modifying a part of PVDF with monomethyl maleate, maleic anhydride, methyl acrylate, or methyl methacrylate can be preferably used.

被覆層中のフッ化ビニリデンを含む重合体の含有率は５０．０〜８０．０質量％であることが好ましく、５０．０〜７０．０質量％であることがより好ましく、５０．０〜６０．０質量％であることがさらに好ましい。
被覆層中のフッ化ビニリデンを含む重合体の含有率が５０．０質量％以上であれば導電性基材への密着性が確保され、被覆層からの炭素微粒子の脱落を防ぐことができる。フッ化ビニリデンを含む重合体の含有率が８０．０質量％以下であれば、粉体状炭素材料の割合が十分であり高い導電性を維持できる。 The content of the polymer containing vinylidene fluoride in the coating layer is preferably 50.0 to 80.0% by mass, more preferably 50.0 to 70.0% by mass, and 50.0 to It is more preferably 60.0% by mass.
When the content of the polymer containing vinylidene fluoride in the coating layer is 50.0% by mass or more, the adhesion to the conductive base material is ensured and the carbon fine particles can be prevented from falling out of the coating layer. When the content of the polymer containing vinylidene fluoride is 80.0 mass% or less, the ratio of the powdery carbon material is sufficient and high conductivity can be maintained.

（フッ素非含有ビニル系重合体）
フッ素非含有ビニル系重合体は、Ｎ−ビニルアセトアミドおよびＮ−ビニルアセトアミド誘導体、ビニルアルコールおよびビニルアルコール誘導体、ビニルピロリドンおよびビニルピロリドン誘導体、ならびに酢酸ビニルおよび酢酸ビニル誘導体からなる群から選ばれる１種をモノマ単位とする単独重合体、または前記の群から選ばれる１種以上をモノマ単位として含む共重合体である。
前記の各誘導体（モノマ単位）としては、本発明に係るフッ素非含有ビニル系重合体の特性が損なわれない範囲で、それぞれ誘導体化する前の元の化合物（モノマ単位）の水素の一部がアルキル基、アルコキシ基、水酸基、カルボキシ基、アミノ基などで置換されたもの、および元の化合物（モノマ単位）の一部がアセチル化、アセタール化、エーテル化、エステル化などにより変性されたものを好適に用いることができる。
フッ素非含有ビニル系重合体の重量平均分子量は好ましくは５万〜１５０万であり、より好ましくは１０万〜９０万である。分子量は、ゲルパーミエーションクロマトグラフィーを用いて、プルランなどの標準サンプルに換算した値として求めることができる。重量平均分子量が上記の範囲であると、後述のフッ素非含有ビニル系重合体の塗工液において粉体状炭素材料の分散性が良好であり、塗布時の増粘や炭素微粒子の凝集を防ぐことができる。これらのフッ素非含有ビニル系重合体は粉体状炭素材料の表面に良好に吸着し、静電反発や立体障害などにより粉体状炭素材料同士が凝集することを抑制していると推定される。 (Fluorine-free vinyl polymer)
The non-fluorine-containing vinyl polymer is one selected from the group consisting of N-vinylacetamide and N-vinylacetamide derivatives, vinyl alcohol and vinyl alcohol derivatives, vinylpyrrolidone and vinylpyrrolidone derivatives, and vinyl acetate and vinyl acetate derivatives. It is a homopolymer having a monomer unit, or a copolymer containing at least one selected from the above group as a monomer unit.
As each of the above-mentioned derivatives (monomer unit), a part of hydrogen of the original compound (monomer unit) before derivatization is contained as long as the characteristics of the fluorine-free vinyl polymer according to the present invention are not impaired. Those substituted with an alkyl group, an alkoxy group, a hydroxyl group, a carboxy group, an amino group, etc., and those in which part of the original compound (monomer unit) has been modified by acetylation, acetalization, etherification, esterification, etc. It can be preferably used.
The weight average molecular weight of the fluorine-free vinyl polymer is preferably 50,000 to 1,500,000, more preferably 100,000 to 900,000. The molecular weight can be obtained as a value converted into a standard sample such as pullulan using gel permeation chromatography. When the weight average molecular weight is in the above range, the dispersibility of the powdery carbon material in the coating liquid of the below-mentioned fluorine-free vinyl polymer is good, and thickening at the time of coating and aggregation of carbon fine particles are prevented. be able to. It is presumed that these fluorine-free vinyl polymers are well adsorbed on the surface of the powdery carbon material and suppress the aggregation of the powdery carbon materials due to electrostatic repulsion and steric hindrance. ..

被覆層中のフッ素非含有ビニル系重合体の含有率は０．０９９〜５．０質量％であり、０．２〜４．０質量％が好ましく、０．３〜３．０質量％がより好ましい。   The content of the fluorine-free vinyl polymer in the coating layer is 0.099 to 5.0% by mass, preferably 0.2 to 4.0% by mass, more preferably 0.3 to 3.0% by mass. preferable.

被覆層中のフッ素非含有ビニル系重合体の含有率が０．０９９〜５．０質量％の範囲であると、被覆層を作製するための塗工液中の粉体状炭素材料の分散性が良好なため、均一な被覆層が形成できる。フッ素非含有ビニル系重合体の含有率が０．０９９質量％未満であると、塗工液中の粉体状炭素材料の分散性が悪化して凝集物が発生するため、被覆層の表面が海島状になり、電極層塗工時の精密な厚み制御に支障をきたす。フッ素非含有ビニル系重合体の含有率が５．０質量％を超えると、蓄電デバイスの抵抗値が上昇するため好ましくない。抵抗値が上昇する原因は明らかではないが、フッ化ビニリデンが炭素粒子や導電性基材と点で接触する傾向があるのに対し、フッ素非含有ビニル化合物は炭素粒子の表面をより被覆しやすいため、炭素粒子同士および炭素粒子と導電性基材との電気的接触が悪くなり抵抗値が上昇するものと推測される。   When the content of the fluorine-free vinyl polymer in the coating layer is in the range of 0.099 to 5.0 mass%, the dispersibility of the powdery carbon material in the coating liquid for preparing the coating layer As a result, a uniform coating layer can be formed. If the content of the fluorine-free vinyl-based polymer is less than 0.099% by mass, the dispersibility of the powdery carbon material in the coating liquid deteriorates and aggregates are generated, so that the surface of the coating layer is It becomes a sea-island shape and interferes with precise thickness control when coating the electrode layer. When the content of the fluorine-free vinyl polymer exceeds 5.0% by mass, the resistance value of the electricity storage device increases, which is not preferable. Although the cause of the increase in resistance is not clear, vinylidene fluoride tends to come into point contact with carbon particles and conductive base materials, whereas fluorine-free vinyl compounds are more likely to cover the surface of carbon particles. Therefore, it is presumed that the electrical contact between the carbon particles and between the carbon particles and the conductive base material deteriorates, and the resistance value increases.

被覆層中のフッ素非含有ビニル系重合体の含有率の測定は、熱分解ガスクロマトグラフィー質量分析法（ＧＣ／ＭＳ）によって行う。前記フッ素非含有ビニル系重合体を含有する前記塗工液または塗工箔を熱分解温度５５０℃、カラム内の流速を１ｍＬ／ｍｉｎとし、得られたクロマトグラムおよびマススペクトルと既知のデータを照合してビニル化合物を同定する。同定したピークのピーク面積からフッ素非含有ビニル系重合体の含有率を求めるための検量線は、例えばフッ素非含有ビニル化合物の含有率が０．１、１．０、５．０質量％の３点について測定を行って作成する。   The content of the fluorine-free vinyl polymer in the coating layer is measured by pyrolysis gas chromatography-mass spectrometry (GC / MS). The coating liquid or coating foil containing the fluorine-free vinyl polymer was pyrolyzed at 550 ° C., the flow rate in the column was 1 mL / min, and the obtained chromatogram and mass spectrum were compared with known data. To identify the vinyl compound. The calibration curve for determining the content of the fluorine-free vinyl polymer from the peak areas of the identified peaks is, for example, 3 when the content of the fluorine-free vinyl compound is 0.1, 1.0 or 5.0% by mass. Create by measuring points.

また、被覆層はフッ化ビニリデンを含む重合体およびフッ素非含有ビニル系重合体以外にその他の樹脂成分を含んでもよい。その他の樹脂はいかなる樹脂でもよく、例えば、多糖類高分子またはその誘導体が架橋剤で架橋された樹脂化合物を用いることができる。また、これ以外にも、ポリアクリル系樹脂、ポリオレフィン系樹脂、ポリエーテル系樹脂、ポリアミド、ポリイミド、ポリアミドイミド、エポキシ系樹脂などを使用してもよい。   Further, the coating layer may contain other resin components in addition to the vinylidene fluoride-containing polymer and the fluorine-free vinyl polymer. The other resin may be any resin, and for example, a resin compound obtained by crosslinking a polysaccharide polymer or a derivative thereof with a crosslinking agent can be used. Other than this, polyacrylic resin, polyolefin resin, polyether resin, polyamide, polyimide, polyamideimide, epoxy resin, etc. may be used.

［蓄電デバイス用集電体を製造するための塗工液］
本発明に係る好ましい実施形態の蓄電デバイス用集電体塗工液は、溶媒中に粉体状炭素材料、モノマ単位としてフッ化ビニリデンを含む重合体およびフッ素非含有ビニル系重合体が溶解または分散している。 [Coating Liquid for Manufacturing Current Collector for Power Storage Device]
The current collector coating liquid for an electricity storage device of a preferred embodiment according to the present invention is a powdery carbon material in a solvent, a polymer containing vinylidene fluoride as a monomer unit and a fluorine-free vinyl polymer are dissolved or dispersed. is doing.

溶媒は、有機溶剤系の溶媒または水系の溶媒のいずれをも用いることができる。有機溶剤系の溶媒としては、特に限定されるものではないが、メタノール、エタノール、イソプロパノール、ヘキサン、アセトン、Ｎ−メチル−２−ピロリドン（ＮＭＰ）等が挙げられ、これらの溶媒は１種単独でまたは２種以上を組み合わせて用いることができる。これらの中で、水またはＮ−メチル−２−ピロリドンを用いることが好ましい。
溶媒として水を用いると、環境負荷も少なく、安価に塗工液を作製することができるため好ましい。
また、有機溶媒としては、塗布後の熱処理の温度以下で蒸発するものが望ましい。具体的には常圧での沸点が１００〜２２０℃のものが好ましい。このような沸点を有する有機溶媒を用いると、塗工作業中に塗工液の濃度が変化しにくいため、所定の厚さを有する被覆層が得られやすい。また、熱処理により溶媒を十分に除去することができる。上記のような沸点を有する有機溶媒としてはＮ−メチル−２−ピロリドンが好ましい。 As the solvent, either an organic solvent-based solvent or an aqueous solvent can be used. Examples of the organic solvent-based solvent include, but are not limited to, methanol, ethanol, isopropanol, hexane, acetone, N-methyl-2-pyrrolidone (NMP) and the like, and these solvents may be used alone. Alternatively, two or more kinds can be used in combination. Among these, it is preferable to use water or N-methyl-2-pyrrolidone.
It is preferable to use water as the solvent because the environmental load is small and the coating liquid can be produced at low cost.
Further, as the organic solvent, those which evaporate at the temperature of the heat treatment after coating or less are desirable. Specifically, those having a boiling point of 100 to 220 ° C. under normal pressure are preferable. When an organic solvent having such a boiling point is used, the concentration of the coating liquid is unlikely to change during the coating operation, so that a coating layer having a predetermined thickness can be easily obtained. Further, the solvent can be sufficiently removed by the heat treatment. N-methyl-2-pyrrolidone is preferable as the organic solvent having the above boiling point.

塗工液において、粉体状炭素材料、フッ化ビニリデンを含む重合体およびフッ素非含有ビニル系重合体は、溶媒中に溶解している必要はなく、溶媒中に分散していてもよい。例えば、水系の溶媒を用いた場合、一般的にフッ化ビニリデンを含む重合体は溶解しないが、溶媒中に懸濁したスラリーとなっていればよい。   In the coating liquid, the powdery carbon material, the vinylidene fluoride-containing polymer and the non-fluorine-containing vinyl polymer need not be dissolved in the solvent and may be dispersed in the solvent. For example, when an aqueous solvent is used, a polymer containing vinylidene fluoride is generally not dissolved, but a slurry suspended in the solvent may be used.

塗工液中の粉体状炭素材料、フッ化ビニリデンを含む重合体およびフッ素非含有ビニル系重合体の合計の含有率は２〜１５質量％であり、５〜１５質量％が好ましく、７〜１５質量％がより好ましい。
さらに、塗工液に含まれる粉体状炭素材料、フッ化ビニリデンを含む重合体およびフッ素非含有ビニル系重合体の合計質量に対するフッ素非含有ビニル系重合体の質量割合は０．０９９〜５．０質量％であり、０．２〜４．０質量％が好ましく、０．３〜３．０質量％がより好ましい。粉体状炭素材料、フッ化ビニリデンを含む重合体およびフッ素非含有ビニル系重合体の合計質量に対するフッ素非含有ビニル系重合体の質量割合が０．０９９〜５．０質量％の範囲であると粉末状炭素材料の分散性が良好なスラリーが得られ、均一な被覆層が形成できる。フッ素非含有ビニル系重合体の質量割合が０．０９９質量％未満であると、粉体状炭素材料の分散性が悪化し凝集物が発生するため塗工性が悪くなる。一方、フッ素非含有ビニル系重合体の質量割合が５．０質量％を超えるとスラリーの粘度が高くなるため塗工性が悪くなり、また、蓄電デバイスの抵抗値が上昇する点からも好ましくない。 The total content of the powdery carbon material, the vinylidene fluoride-containing polymer and the fluorine-free vinyl polymer in the coating liquid is 2 to 15% by mass, preferably 5 to 15% by mass, and 7 to 15 mass% is more preferable.
Further, the mass ratio of the non-fluorine-containing vinyl polymer to the total mass of the powdery carbon material, the vinylidene fluoride-containing polymer and the non-fluorine-containing vinyl polymer contained in the coating liquid is 0.099 to 5. It is 0 mass%, 0.2 to 4.0 mass% is preferable, and 0.3 to 3.0 mass% is more preferable. When the mass ratio of the non-fluorine-containing vinyl polymer to the total mass of the powdery carbon material, the vinylidene fluoride-containing polymer and the non-fluorine-containing vinyl polymer is in the range of 0.099 to 5.0 mass%. A slurry having good dispersibility of the powdery carbon material can be obtained, and a uniform coating layer can be formed. When the mass ratio of the fluorine-free vinyl polymer is less than 0.099 mass%, the dispersibility of the powdery carbon material deteriorates and aggregates are generated, resulting in poor coatability. On the other hand, if the mass ratio of the non-fluorine-containing vinyl polymer exceeds 5.0 mass%, the viscosity of the slurry will be high and the coatability will be poor, and the resistance value of the electricity storage device will be increased, which is not preferable. ..

塗工液中の粉末状炭素材料、フッ化ビニリデンを含む重合体およびフッ素非含有ビニル系重合体の合計の含有率が上記範囲であり、かつ塗工液に含まれる粉体状炭素材料、フッ化ビニリデンを含む重合体およびフッ素非含有ビニル系重合体の合計質量に対するフッ素非含有ビニル系重合体の質量割合が上記の範囲であると、粉体状炭素材料の分散性が良好で、かつ液粘度が適正になり、一般的な塗工方法が選択でき、容易に蓄電デバイス用集電体が作製することができる。このとき塗工液の塗工時の温度での粘度は、５０〜３０００ｍＰａ・ｓであることが好ましく、５０〜１０００ｍＰａ・ｓであることがより好ましく、５０〜３００ｍＰａ・ｓであることがより一層好ましい。塗工液の粘度が３０００ｍＰａ・ｓ以下であれば、基材への塗工が容易に行える。また、塗工液の粘度が５０ｍＰａ・ｓ以上であれば、十分な膜厚を基材上に形成することができる。
粘度の測定はＢ型粘度計を用いて行い、測定する粘度レンジに適したロータ、回転数を選択する。例えば、数百ｍＰａ・ｓ程度の塗工液の粘度を測定する場合には、Ｎｏ．２ロータを使用し、回転数は６０ｒｐｍとする。 The total content of the powdery carbon material, the vinylidene fluoride-containing polymer and the fluorine-free vinyl polymer in the coating solution is within the above range, and the powdery carbon material and the fluorine-containing material contained in the coating solution When the mass ratio of the non-fluorine-containing vinyl polymer to the total mass of the vinylidene chloride-containing polymer and the non-fluorine-containing vinyl polymer is in the above range, the dispersibility of the powdery carbon material is good, and the liquid The viscosity becomes appropriate, a general coating method can be selected, and a current collector for an electricity storage device can be easily manufactured. At this time, the viscosity of the coating liquid at the time of coating is preferably 50 to 3000 mPa · s, more preferably 50 to 1000 mPa · s, and further preferably 50 to 300 mPa · s. preferable. When the viscosity of the coating liquid is 3000 mPa · s or less, the coating on the substrate can be easily performed. Further, when the viscosity of the coating liquid is 50 mPa · s or more, a sufficient film thickness can be formed on the base material.
Viscosity is measured using a B-type viscometer, and a rotor and rotation speed suitable for the viscosity range to be measured are selected. For example, when measuring the viscosity of the coating liquid of several hundreds mPa · s, No. Two rotors are used and the rotation speed is 60 rpm.

［蓄電デバイス用集電体の製造方法］
本発明に係る蓄電デバイス用集電体の製造方法は、溶媒中に粉体状炭素材料、モノマ単位としてフッ化ビニリデンを含む重合体およびフッ素非含有ビニル系重合体が溶解または分散した塗工液を調製する工程、調製した塗工液をシート状の導電性基材の片面または両面に塗布する工程、および塗布した塗工液を乾燥させる工程を有する。粉体状炭素材料、フッ化ビニリデンを含む重合体およびフッ素非含有ビニル系重合体は、上記のものを用いることができる。 [Method for manufacturing current collector for electricity storage device]
The method for producing a current collector for an electricity storage device according to the present invention is a coating liquid in which a powdery carbon material, a polymer containing vinylidene fluoride as a monomer unit, and a fluorine-free vinyl polymer are dissolved or dispersed in a solvent. And a step of applying the prepared coating liquid to one or both surfaces of a sheet-shaped conductive substrate, and a step of drying the applied coating liquid. As the powdery carbon material, the vinylidene fluoride-containing polymer, and the fluorine-free vinyl-based polymer, those described above can be used.

塗工液を導電性基材の片面または両面に塗布する方法は特に限定されるものではないが、グラビアコート、ダイコート、バーコート、スピンコート、ニップコート等の一般的な塗工方法を用いることができる。   The method of applying the coating liquid on one or both sides of the conductive substrate is not particularly limited, but a general coating method such as gravure coating, die coating, bar coating, spin coating, or nip coating is used. You can

塗布した塗工液を乾燥させて基材上に被覆層を形成する。乾燥は、十分に溶媒を蒸発させるために、５０℃以上の温度で行うことが好ましい。
塗工液が熱硬化性樹脂成分を有する場合は、この樹脂成分を硬化させることが好ましい。熱硬化性樹脂が含まれている場合は、樹脂の硬化温度（架橋反応温度）以上で乾燥することがより好ましい。塗工液は、このような硬化反応を促進させる触媒、重合剤、架橋剤等を含んでもよい。 The applied coating liquid is dried to form a coating layer on the base material. Drying is preferably performed at a temperature of 50 ° C. or higher in order to sufficiently evaporate the solvent.
When the coating liquid has a thermosetting resin component, it is preferable to cure this resin component. When a thermosetting resin is contained, it is more preferable to dry at a temperature not lower than the curing temperature (crosslinking reaction temperature) of the resin. The coating liquid may contain a catalyst, a polymerizing agent, a cross-linking agent, etc. that accelerates such curing reaction.

［電極］
本発明に係る蓄電デバイス用集電体を用いたリチウムイオン二次電池を例に説明する。本発明の蓄電デバイス用集電体は高電圧仕様の正極活物質を用いた電極に適用することで効果を発揮することが期待されるが、特定の正極集電体に限定されず、また負極集電体に用いてもよい。正極、負極どちらでも集電体と電極の界面抵抗を低減する効果は得られるため、低抵抗な蓄電デバイスが得られる。 [electrode]
A lithium ion secondary battery using the current collector for an electricity storage device according to the present invention will be described as an example. The current collector for an electricity storage device of the present invention is expected to exert effects by being applied to an electrode using a high-voltage specification positive electrode active material, but is not limited to a specific positive electrode current collector, and a negative electrode You may use it for a collector. Since the effect of reducing the interface resistance between the current collector and the electrode can be obtained with either the positive electrode or the negative electrode, a low-resistance electricity storage device can be obtained.

正極は、溶媒中に正極活物質、正極用導電助剤およびバインダーが溶解または分散したスラリーを、本発明の蓄電デバイス用集電体上に塗布・乾燥させることにより形成される。ここで、バインダーとしては、有機溶剤系の溶媒に溶解することができるＰＶＤＦ等を用いることが一般的である。また、ＳＢＲやアクリル系樹脂等を含む水系のスラリーを用いることもできる。   The positive electrode is formed by applying and drying a slurry in which a positive electrode active material, a positive electrode conductive auxiliary agent and a binder are dissolved or dispersed in a solvent on the current collector for an electricity storage device of the present invention. Here, as the binder, it is common to use PVDF or the like that can be dissolved in an organic solvent-based solvent. Alternatively, an aqueous slurry containing SBR, acrylic resin, or the like can be used.

正極活物質、正極用導電助剤は公知のものを用いることができる。
正極活物質としては、例えば、コバルト酸リチウム（ＬｉＣｏＯ２）、マンガン酸リチウム（ＬｉＭｎ２Ｏ４）、ニッケル酸リチウム（ＬｉＮｉＯ２）、さらには、コバルト酸リチウムのＣｏの一部をＭｎとＮｉで置換した３元系リチウム化合物（Ｌｉ（ＣｏｘＭｎｙＮｉｚ）Ｏ２）、ニッケル酸リチウムのＮｉの一部をＣｏとＡｌで置換した（Ｌｉ（ＮｉｘＣｏｙＡｌｚ）Ｏ２）、オリビン系（ＬｉＦｅＰＯ４、ＬｉＭｎＰＯ４）などが好適である。正極用導電助剤としては、例えば、アセチレンブラック、ファーネスブラック、ケッチェンブラック等のカーボンブラック、気相法炭素繊維、黒鉛微粉などが好適である。 Known materials can be used for the positive electrode active material and the positive electrode conduction aid.
Examples of the positive electrode active material include lithium cobalt oxide (LiCoO 2 ), lithium manganate (LiMn 2 O 4 ), lithium nickel oxide (LiNiO 2 ), and further, a part of Co of lithium cobalt oxide is Mn and Ni. ternary lithium substituted compound (Li (Co x Mn y Ni z) O 2), a part of Ni of lithium nickelate was replaced by Co and Al (Li (Ni x Co y Al z) O 2), Olivine-based (LiFePO 4 , LiMnPO 4 ) and the like are suitable. As the conductive additive for the positive electrode, for example, carbon black such as acetylene black, furnace black, Ketjen black, vapor grown carbon fiber, and fine graphite powder are suitable.

負極は、溶媒中に負極活物質、負極用導電助剤およびバインダーが溶解または分散したスラリーを、本発明の蓄電デバイス用集電体上に塗布・乾燥させることにより形成される。ここで、バインダーとしては、有機溶媒ではＰＶＤＦ等を用いることが一般的であり、水系溶媒ではＳＢＲやアクリル系樹脂等を用いることが一般的である。   The negative electrode is formed by applying and drying a slurry in which a negative electrode active material, a conductive auxiliary agent for a negative electrode and a binder are dissolved or dispersed in a solvent on the current collector for an electricity storage device of the present invention. Here, as the binder, PVDF or the like is generally used as the organic solvent, and SBR or acrylic resin or the like is generally used as the aqueous solvent.

負極活物質、負極用導電助剤は公知のものを用いることができる。
負極活物質としては、例えば、天然黒鉛や人造黒鉛などの黒鉛系、ケイ素や錫の元素を含む合金系、チタン酸リチウムなどのチタン含有酸化物系、またはこれらの混合系などが好適に用いられる。負極用導電助剤としては、例えば、アセチレンブラック、ファーネスブラック、ケッチェンブラック等のカーボンブラック、気相法炭素繊維などが好適に用いられる。 Known materials can be used as the negative electrode active material and the negative electrode conduction aid.
As the negative electrode active material, for example, a graphite-based material such as natural graphite or artificial graphite, an alloy-based material containing an element of silicon or tin, a titanium-containing oxide-based material such as lithium titanate, or a mixed system thereof is preferably used. .. As the negative electrode conduction aid, for example, carbon black such as acetylene black, furnace black and Ketjen black, vapor grown carbon fiber and the like are preferably used.

［リチウムイオン二次電池］
本発明の一態様に係るリチウムイオン二次電池は、上記の電極を備えている。電極は、導電性基材上に被覆層が形成されて集電体をなし、その被覆層上に、正極活物質または負極活物質と導電助剤とバインダーを含む電極活物質層を有し、正極と負極とが、セパレータを介して接合され、さらに内部を電解液で充填し、外装材を備えることで形成されている。 [Lithium-ion secondary battery]
A lithium ion secondary battery according to one aspect of the present invention includes the above electrode. The electrode has a coating layer formed on a conductive base material to form a current collector, and on the coating layer, an electrode active material layer containing a positive electrode active material or a negative electrode active material, a conductive additive, and a binder, It is formed by joining the positive electrode and the negative electrode via a separator, filling the inside with an electrolytic solution, and providing an exterior material.

電極以外の蓄電デバイスの構成要素である電解液、セパレータ、外装材は、いずれも公知のものを用いることができる。電解液は、液体に限られず、ゲル状あるいは固体のものを用いることもできる。セパレータは、例えば、ポリプロピレン、ポリエチレン等のフィルムが好適に用いられる。   As the electrolytic solution, the separator, and the exterior material, which are components of the electricity storage device other than the electrodes, known materials can be used. The electrolytic solution is not limited to a liquid, and a gel or solid electrolytic solution can be used. As the separator, for example, a film of polypropylene, polyethylene or the like is preferably used.

リチウムイオン二次電池は、正極および負極にモーターや光源などの負荷を接続することで放電が可能となり、電源を接続することで充電が可能となる。   The lithium-ion secondary battery can be discharged by connecting a load such as a motor or a light source to the positive electrode and the negative electrode, and can be charged by connecting a power source.

リチウムイオン二次電池の電極に、導電性基材の表面に本発明の被覆層を備えた集電体を用いると、従来の集電体の場合と比較して、電極の抵抗値を下げることができる。すなわち、リチウムイオン二次電池の内部抵抗の低減を実現することができる。また、本発明の蓄電デバイス用集電体を用いることにより、高電圧用活物質を適用したリチウムイオン二次電池の高電圧充電が可能になり、高容量のリチウムイオン二次電池を実現することができる。   When the current collector having the coating layer of the present invention on the surface of the conductive base material is used for the electrode of the lithium ion secondary battery, the resistance value of the electrode can be reduced as compared with the case of the conventional current collector. You can That is, it is possible to reduce the internal resistance of the lithium-ion secondary battery. Further, by using the current collector for an electricity storage device of the present invention, it becomes possible to charge a lithium-ion secondary battery to which a high-voltage active material is applied at high voltage, and to realize a high-capacity lithium-ion secondary battery. You can

［塗工液の評価］
＜粉体状炭素材料の分散性＞
塗工液における粉体状炭素材料の分散性の評価は、具体的には鉛直に保持した５０ｍＬのガラス製試験管の壁面に塗工液を５ｍＬ垂らして投入し、５分経過後の壁面の様子を肉眼で観察して行った。壁面に凝集物が観察されない場合を分散性が良好であると判定し、凝集物が観察される場合を分散性が悪いと判定した。 [Evaluation of coating liquid]
<Dispersibility of powdery carbon material>
To evaluate the dispersibility of the powdery carbon material in the coating liquid, specifically, 5 mL of the coating liquid was dropped onto the wall surface of a vertically held 50 mL glass test tube, and after 5 minutes, the wall surface The condition was visually observed. When the aggregates were not observed on the wall surface, the dispersibility was determined to be good, and when the aggregates were observed, the dispersibility was determined to be poor.

［リチウムイオン二次電池の評価］
＜正極シートの作製＞
正極活物質としてＬｉＦｅＰＯ４（Ａｌｅｅｅｓ社製、Ｍ１２１）９０質量部、導電助剤として導電性カーボンブラック（Ｉｍｅｒｙｓ社製、ＳＵＰＥＲ Ｐ）５質量部、バインダーとしてポリフッ化ビニリデン（Ａｒｋｅｍａ社製、ＨＳＶ−９００）５質量部にＮ−メチル−２−ピロリドンを適宜加えながら攪拌・混合し、スラリー状の分散液を作製した。作製した分散液を下記の実施例および比較例で使用する集電体上にクリアランス２００μｍのドクターブレードを用いて塗布し、乾燥させ、加圧成形して、正極シートを得た。
＜負極シートの作製＞
負極活物質として人造黒鉛（昭和電工株式会社製、ＳＣＭＧ（登録商標）−ＡＲ）９５質量部、導電助剤として導電性カーボンブラック（Ｉｍｅｒｙｓ社製、ＳＵＰＥＲ Ｐ）１質量部、バインダーとしてスチレンブタジエンラバー（日本ゼオン株式会社製、ＢＭ−４００Ｂ）３質量部（固形分換算）、増粘剤としてカルボキシメチルセルロース（ダイセルファインケム株式会社製、＃１３８０）１質量部（固形分換算）に水を適宜加えながら攪拌・混合し、スラリー状の分散液を作製した。作製した分散液を厚さ２０μｍの銅箔上にクリアランス２００μｍのドクターブレードで塗布し、乾燥させ、加圧成形して、負極シートを得た。
＜評価用ラミネートセルの作製＞
上記のように作製された正極シートと負極シートとをポリプロピレン製セパレータ（Ｃｅｌｇａｒｄ社製、セルガード２５００）を間に挟んで重ね合せた。それをアルミラミネート包材の中に入れ、電解液を注入し、真空中でヒートシールして、評価用のラミネートセルを得た。
電解液は、エチレンカーボネートとエチルメチルカーボネートが体積比３：７で混合された溶媒に、電解質としてＬｉＰＦ6を１ｍｏｌ／Ｌ、また添加剤としてビニレンカーボネートを１質量％で溶解させた液を用いた。
以上のようにして、定格容量１００ｍＡｈ（１Ｃ＝１００ｍＡ）のセルを作製した。
＜電池の直流内部抵抗（ＤＣ−ＩＲ）の評価＞
電池の直流内部抵抗（ＤＣ−ＩＲ）は、初期充放電を経たセルを充電深度（ＳＯＣ）５０％に調整後、室温環境下の下、０．１Ｃ〜２Ｃ間の５点で各々５秒間放電し、その前後の電圧変化量を充放電装置で計測した。５点の電圧変化量／電流の値の平均値として直流内部抵抗を算出した。 [Evaluation of lithium-ion secondary battery]
<Production of positive electrode sheet>
90 parts by mass of LiFePO 4 (Aleees, M121) as a positive electrode active material, 5 parts by mass of conductive carbon black (manufactured by Imerys, SUPER P) as a conduction aid, and polyvinylidene fluoride (Arkema, HSV-900) as a binder. ) N-methyl-2-pyrrolidone was appropriately added to 5 parts by mass while stirring and mixing to prepare a slurry-like dispersion liquid. The prepared dispersion liquid was applied onto a current collector used in the following Examples and Comparative Examples using a doctor blade having a clearance of 200 μm, dried, and pressure-molded to obtain a positive electrode sheet.
<Preparation of negative electrode sheet>
Artificial graphite (Showa Denko KK, SCMG (registered trademark) -AR) 95 parts by mass as a negative electrode active material, conductive carbon black (Sumer P manufactured by Imerys, Inc.) as a conductive auxiliary agent, and styrene-butadiene rubber as a binder. (Nippon Zeon Co., Ltd., BM-400B) 3 parts by mass (solid content conversion), while adding water appropriately to carboxymethylcellulose (manufactured by Daicel Finechem Co., Ltd., # 1380) 1 part by mass (solid content conversion) as a thickener. The mixture was stirred and mixed to prepare a slurry-like dispersion liquid. The prepared dispersion was applied onto a copper foil having a thickness of 20 μm with a doctor blade having a clearance of 200 μm, dried and pressure-molded to obtain a negative electrode sheet.
<Production of laminated cell for evaluation>
The positive electrode sheet and the negative electrode sheet produced as described above were superposed with a polypropylene separator (Celgard 2500, Celgard 2500) interposed therebetween. It was put in an aluminum laminate packaging material, an electrolytic solution was injected, and heat sealing was performed in a vacuum to obtain a laminated cell for evaluation.
The electrolytic solution used was a solution in which 1 mol / L of LiPF 6 as an electrolyte and 1% by mass of vinylene carbonate as an additive were dissolved in a solvent in which ethylene carbonate and ethylmethyl carbonate were mixed at a volume ratio of 3: 7. ..
As described above, a cell having a rated capacity of 100 mAh (1 C = 100 mA) was produced.
<Evaluation of direct current internal resistance (DC-IR) of battery>
The direct current internal resistance (DC-IR) of the battery is adjusted to 50% of the depth of charge (SOC) of the cell that has undergone initial charge / discharge, and then discharged at 5 points between 0.1C and 2C for 5 seconds under a room temperature environment. Then, the amount of voltage change before and after that was measured by a charge / discharge device. The DC internal resistance was calculated as the average value of the voltage change amount / current value at 5 points.

（実施例１−１）
集電体製造用の塗工液を作製するために、バインダー（フッ化ビニリデンを含む重合体）としてＰＶＤＦ水系ディスパージョン（重量平均分子量（Ｍｗ）：７３万、酸変性：アクリル酸）を固形分換算で７０質量部、粉体状炭素材料として一次粒子径が４８ｎｍのアセチレンブラック（デンカ株式会社製、デンカブラック（登録商標）、ＨＳ−１００）３０質量部、さらにフッ素非含有ビニル系重合体としてポリ−Ｎ−ビニルアセトアミド（ＰＮＶＡ（登録商標）、昭和電工株式会社製）０．１質量部を用意した。表１に、粉体状炭素材料、フッ化ビニリデンを含む重合体およびフッ素非含有ビニル系重合体の添加量（質量部）と被覆層中の含有率（質量％）を示す（表２、３についても同様）。
まず、アセチレンブラックとＰＮＶＡ（登録商標）と適量の純水を混合し、その混合液をディスパジャータイプの攪拌機（株式会社日本精機製、エクセルオートホモジナイザー）を使用し４０００ｒｐｍで３０分間混合した後、ＰＶＤＦ水系ディスパージョンを加え、さらに固形分濃度が７質量％になるように純水を加えた。その混合液を前記ディスパジャータイプの攪拌機を使用し５００ｒｐｍで３分間混合して塗工液を得た。
得られた塗工液におけるアセチレンブラックの分散性を評価したところ、凝集物は見られず分散性は良好であった（図１）。
次に、材質ＡＬＮ３０、厚さ１５μｍのアルミ箔を用意し、この上にアプリケーターを用いて塗工液を塗布した。その後、８０℃の乾燥機で５分間乾燥し、集電体を得た。目付量は０．５２ｇ／ｍ２であった。
得られた集電体を用いて前記の方法により二次電池を作製して内部抵抗を求めたところ、３００ｍΩであった（表１）。 (Example 1-1)
In order to prepare a coating liquid for producing a current collector, PVDF aqueous dispersion (weight average molecular weight (Mw): 730,000, acid modification: acrylic acid) is used as a binder (polymer containing vinylidene fluoride) in a solid content. 70 parts by mass of conversion, 30 parts by mass of acetylene black (Denka Corporation, Denka Black (registered trademark), HS-100) having a primary particle diameter of 48 nm as a powdery carbon material, and further as a fluorine-free vinyl polymer 0.1 part by mass of poly-N-vinylacetamide (PNVA (registered trademark), Showa Denko KK) was prepared. Table 1 shows the addition amount (parts by mass) of the powdery carbon material, the vinylidene fluoride-containing polymer and the fluorine-free vinyl polymer and the content rate (mass%) in the coating layer (Tables 2, 3). Also for).
First, acetylene black, PNVA (registered trademark) and an appropriate amount of pure water were mixed, and the mixture was mixed for 30 minutes at 4000 rpm using a disperser type stirrer (Nippon Seiki Co., Ltd. Excel Auto Homogenizer), A PVDF aqueous dispersion was added, and further pure water was added so that the solid content concentration was 7% by mass. The mixed liquid was mixed for 3 minutes at 500 rpm using the above-mentioned disperser-type stirrer to obtain a coating liquid.
When the dispersibility of acetylene black in the obtained coating liquid was evaluated, no dispersant was observed and the dispersibility was good (FIG. 1).
Next, an aluminum foil having a material of ALN30 and a thickness of 15 μm was prepared, and the coating liquid was applied onto the aluminum foil using an applicator. Then, it dried for 5 minutes with the 80 degreeC dryer, and obtained the electrical power collector. The basis weight was 0.52 g / m 2 .
Using the obtained current collector, a secondary battery was prepared by the above method and the internal resistance was determined to be 300 mΩ (Table 1).

（実施例１−２〜６）
ＰＮＶＡの添加量をそれぞれ０．３、０．５、１．０、３．０および５．０質量部とした以外は実施例１−１と同様にして塗工液を作製して分散性を評価し、二次電池を作製して内部抵抗を評価した。評価結果を表１に示す。また、実施例１−６の塗工液の分散性の観察結果を図２に示すが、凝集物が見られず分散性は良好であった。 (Examples 1-2 to 6)
A coating solution was prepared in the same manner as in Example 1-1 except that the amounts of PNVA added were 0.3, 0.5, 1.0, 3.0 and 5.0 parts by mass, respectively, to improve dispersibility. The secondary battery was evaluated, and the internal resistance was evaluated. The evaluation results are shown in Table 1. Further, FIG. 2 shows the results of observing the dispersibility of the coating liquids of Examples 1-6. The dispersibility was good because no aggregate was observed.

（比較例１−１〜３）
ＰＮＶＡの添加量をそれぞれ０、６および１０質量部とした以外は、実施例１−１と同様にして塗工液を作製して分散性を評価し、二次電池を作製して内部抵抗を評価した。ここで、添加量が０質量部とは添加しないことを表す（以下同様）。評価結果を表１に示す。また、比較例１−１の塗工液の分散性の観察結果を図３に示すが、凝集物が見られ分散性は悪かった。 (Comparative Examples 1-1 to 3)
A coating liquid was prepared and dispersibility was evaluated in the same manner as in Example 1-1, except that the amounts of PNVA added were 0, 6 and 10 parts by mass, respectively, and a secondary battery was prepared to determine the internal resistance. evaluated. Here, the addition amount of 0 parts by mass means that no addition is made (the same applies hereinafter). The evaluation results are shown in Table 1. Further, FIG. 3 shows the results of observation of the dispersibility of the coating liquid of Comparative Example 1-1, but aggregates were observed and the dispersibility was poor.

（実施例２−１）
ＰＮＶＡの代わりにポリビニルアルコール（ＰＶＡ、日本合成化学工業株式会社製）を使用した以外は実施例１−１と同様にして塗工液を作製して分散性を評価し、二次電池を作製して内部抵抗を評価した。評価結果を表１に示す。 (Example 2-1)
A coating solution was prepared in the same manner as in Example 1-1 except that polyvinyl alcohol (PVA, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) was used instead of PNVA, the dispersibility was evaluated, and a secondary battery was prepared. The internal resistance was evaluated. The evaluation results are shown in Table 1.

（実施例２−２〜６）
ＰＶＡの添加量をそれぞれ０．３、０．５、１．０、３．０および５．０質量部とした以外は実施例２−１と同様にして塗工液を作製して分散性を評価し、二次電池を作製して内部抵抗を評価した。評価結果を表１に示す。 (Examples 2 to 2-6)
A coating solution was prepared in the same manner as in Example 2-1 except that the amounts of PVA added were 0.3, 0.5, 1.0, 3.0 and 5.0 parts by mass, respectively, to improve dispersibility. The secondary battery was evaluated, and the internal resistance was evaluated. The evaluation results are shown in Table 1.

（比較例２−１〜３）
ＰＶＡの添加量をそれぞれ０．６および１０質量部とした以外は実施例２−１と同様にして塗工液を作製して分散性を評価し、二次電池を作製して内部抵抗を評価した。評価結果を表１に示す。 (Comparative Examples 2-1 to 3)
A coating solution was prepared and dispersibility was evaluated in the same manner as in Example 2-1, except that the amounts of PVA added were changed to 0.6 and 10 parts by mass, respectively, and a secondary battery was prepared to evaluate the internal resistance. did. The evaluation results are shown in Table 1.

（実施例３−１）
バインダーとしてＰＶＤＦ粉末（Ｍｗ＝６３万、酸変性：アクリル酸）７０質量部、一次粒子径が４９ｎｍのアセチレンブラック（デンカ株式会社製、デンカブラック（登録商標）、ＨＳ−１００）３０質量部、ポリビニルピロリドン（ＰＶＰ、第一工業製薬株式会社製）０．１質量部を用意し、これに固形分濃度が７質量％になるようにＮ−メチル−２−ピロリドン（ＮＭＰ）を加えた。その混合液をディスパジャータイプの攪拌機（株式会社日本精機製、エクセルオートホモジナイザー）を使用し４０００ｒｐｍで３０分間混合して塗工液を得た。それ以外は、実施例１−１と同様にして分散性を評価し、二次電池を作製して内部抵抗を評価した。評価結果を表１に示す。 (Example 3-1)
70 parts by mass of PVDF powder (Mw = 630,000, acid modified: acrylic acid) as a binder, 30 parts by mass of acetylene black (Denka Corporation, Denka Black (registered trademark), HS-100) having a primary particle diameter of 49 nm, polyvinyl. Pyrrolidone (PVP, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) was prepared in an amount of 0.1 part by mass, and N-methyl-2-pyrrolidone (NMP) was added thereto so that the solid content concentration was 7% by mass. The mixture was mixed for 30 minutes at 4000 rpm using a disperser type stirrer (Nippon Seiki Co., Ltd., Excel Auto Homogenizer) to obtain a coating solution. Otherwise, the dispersibility was evaluated in the same manner as in Example 1-1, a secondary battery was prepared, and the internal resistance was evaluated. The evaluation results are shown in Table 1.

（実施例３−２〜６）
ＰＶＰの添加量を０．３、０．５、１．０、３．０および５．０質量部とした以外は、実施例３−１と同様にして塗工液を作製して分散性を評価し、二次電池を作製して内部抵抗を評価した。評価結果を表１に示す。 (Examples 3 to 2-6)
A coating liquid was prepared in the same manner as in Example 3-1, except that the addition amount of PVP was 0.3, 0.5, 1.0, 3.0 and 5.0 parts by mass to improve the dispersibility. The secondary battery was evaluated, and the internal resistance was evaluated. The evaluation results are shown in Table 1.

（比較例３−１〜３）
ＰＶＰの添加量を０、６および１０質量部とした以外は、実施例３−１と同様にして塗工液を作製して分散性を評価し、二次電池を作製して内部抵抗を評価した。評価結果を表１に示す。 (Comparative Examples 3-1 to 3)
A coating liquid was prepared and dispersibility was evaluated in the same manner as in Example 3-1, except that the addition amount of PVP was changed to 0, 6 and 10 parts by mass, and a secondary battery was prepared to evaluate internal resistance. did. The evaluation results are shown in Table 1.

（実施例４−１）
バインダーとしてＰＶＤＦ粉末（Ｍｗ＝６３万、酸変性：アクリル酸）の代わりにＰＶＤＦ粉末（Ｍｗ＝１２０万、酸変性：アクリル酸）を使用し、ＰＶＰの代わりにポリ酢酸ビニル（ＰＶＡｃ、日本酢ビ・ポバール株式会社製）を使用した以外は実施例３−１と同様にして塗工液を作製して分散性を評価し、二次電池を作製して内部抵抗を評価した。評価結果を表２に示す。 (Example 4-1)
PVDF powder (Mw = 1.2 million, acid modified: acrylic acid) was used as a binder instead of PVDF powder (Mw = 630,000, acid modified: acrylic acid), and polyvinyl acetate (PVAc, Japan Vinyl Acetate) was used instead of PVP. -A coating solution was prepared and dispersibility was evaluated in the same manner as in Example 3-1, except that Povar Co., Ltd.) was used, and a secondary battery was prepared and internal resistance was evaluated. The evaluation results are shown in Table 2.

（実施例４−２〜６）
ＰＶＡｃの添加量を０．３、０．５、１．０、３．０および５．０質量部とした以外は実施例４−１と同様にして塗工液を作製して分散性を評価し、二次電池を作製して内部抵抗を評価した。評価結果を表２に示す。 (Examples 4-2 to 6)
A coating liquid was prepared in the same manner as in Example 4-1, except that the amount of PVAc added was 0.3, 0.5, 1.0, 3.0 and 5.0 parts by mass, and the dispersibility was evaluated. Then, a secondary battery was manufactured and the internal resistance was evaluated. The evaluation results are shown in Table 2.

（比較例４−１〜３）
ＰＶＡｃの添加量を０、６および１０質量部とした以外は実施例４−１と同様に塗工液を作製して分散性を評価し、二次電池を作製して内部抵抗を評価した。評価結果を表２に示す。 (Comparative Examples 4-1 to 3)
A coating solution was prepared and dispersibility was evaluated in the same manner as in Example 4-1, except that the amount of PVAc added was changed to 0, 6 and 10 parts by mass, and a secondary battery was prepared and evaluated for internal resistance. The evaluation results are shown in Table 2.

（実施例５−１）
ＰＮＶＡの代わりにエチレン−酢酸ビニル共重合体（ＥＶＡ、三菱化学株式会社製）を使用した以外は実施例１−１と同様にして塗工液を作製して分散性を評価し、二次電池を作製して内部抵抗を評価した。評価結果を表２に示す。 (Example 5-1)
A coating liquid was prepared in the same manner as in Example 1-1, except that an ethylene-vinyl acetate copolymer (EVA, manufactured by Mitsubishi Chemical Co., Ltd.) was used instead of PNVA, and the dispersibility was evaluated. Was prepared and the internal resistance was evaluated. The evaluation results are shown in Table 2.

（実施例５−２〜６）
ＥＶＡの添加量を０．３、０．５、１．０、３．０および５．０質量部とした以外は実施例５−１と同様にして塗工液を作製して分散性を評価し、二次電池を作製して内部抵抗を評価した。評価結果を表２に示す。 (Examples 5-2 to 6)
Dispersion was evaluated by preparing a coating liquid in the same manner as in Example 5-1 except that the amount of EVA added was 0.3, 0.5, 1.0, 3.0 and 5.0 parts by mass. Then, a secondary battery was manufactured and the internal resistance was evaluated. The evaluation results are shown in Table 2.

（比較例５−１〜３）
ＥＶＡの添加量を０、６および１０質量部とした以外は実施例５−１と同様にして塗工液を作製して分散性を評価し、二次電池を作製して内部抵抗を評価した。評価結果を表２に示す。 (Comparative Examples 5-1 to 3)
A coating liquid was prepared and dispersibility was evaluated in the same manner as in Example 5-1, except that the addition amount of EVA was 0, 6 and 10 parts by mass, and a secondary battery was prepared and internal resistance was evaluated. .. The evaluation results are shown in Table 2.

（実施例６−１）
ＰＶＰの代わりに（ビニルアルコール−ビニルピロリドン）共重合体（Ｐ（ＶＡ−ＶＰ）、第一工業製薬株式会社製）を使用した以外は実施例４−１と同様にして塗工液を作製して分散性を評価し、二次電池を作製して内部抵抗を評価した。評価結果を表２に示す。 (Example 6-1)
A coating liquid was prepared in the same manner as in Example 4-1 except that a (vinyl alcohol-vinylpyrrolidone) copolymer (P (VA-VP), manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) was used instead of PVP. The dispersibility was evaluated by using a secondary battery and the internal resistance was evaluated. The evaluation results are shown in Table 2.

（実施例６−２〜６）
Ｐ（ＶＡ−ＶＰ）の添加量を０．３、０．５、１．０、３．０および５．０質量部とした以外は実施例６−１と同様にして塗工液を作製して分散性を評価し、二次電池を作製して内部抵抗を評価した。評価結果を表２に示す。 (Examples 6-2 to 6)
A coating liquid was prepared in the same manner as in Example 6-1 except that the addition amount of P (VA-VP) was 0.3, 0.5, 1.0, 3.0 and 5.0 parts by mass. The dispersibility was evaluated by using a secondary battery and the internal resistance was evaluated. The evaluation results are shown in Table 2.

（比較例６−１〜３）
Ｐ（ＶＡ−ＶＰ）の添加量を０、６および１０質量部とした以外は実施例６−１と同様にして塗工液を作製して分散性を評価し、二次電池を作製して内部抵抗を評価した。評価結果を表２に示す。 (Comparative Examples 6-1 to 3)
A coating liquid was prepared and dispersibility was evaluated in the same manner as in Example 6-1, except that the addition amount of P (VA-VP) was changed to 0, 6 and 10 parts by mass, and a secondary battery was prepared. The internal resistance was evaluated. The evaluation results are shown in Table 2.

（比較例７−１〜９）
ＰＶＡｃの代わりにポリエチレングリコール（ＰＥＯ、日油株式会社製）を使用し、その添加量を０、０．１、０．３、０．５、１．０、３．０、５．０、６．０および１０．０質量％とした以外は実施例４と同様にして塗工液を作製して分散性を評価し、二次電池を作製して内部抵抗を評価した。評価結果を表３に示す。 (Comparative Examples 7-1 to 9)
Polyethylene glycol (PEO, manufactured by NOF CORPORATION) was used instead of PVAc, and the addition amount was 0, 0.1, 0.3, 0.5, 1.0, 3.0, 5.0, 6 A coating liquid was prepared and dispersibility was evaluated in the same manner as in Example 4 except that the content was changed to 0.0 and 10.0% by mass, and a secondary battery was prepared and internal resistance was evaluated. The evaluation results are shown in Table 3.

（比較例８−１〜９）
ＰＥＯの代わりにポリアクリル酸（ＰＡＡ、東亜合成株式会社製）を使用した以外は比較例７−１〜９と同様にして塗工液を作製して分散性を評価し、二次電池を作製して内部抵抗を評価した。評価結果を表３に示す。 (Comparative Examples 8-1 to 9)
A coating solution was prepared in the same manner as in Comparative Examples 7-1 to 9 except that polyacrylic acid (PAA, manufactured by Toagosei Co., Ltd.) was used instead of PEO, and the dispersibility was evaluated to prepare a secondary battery. Then, the internal resistance was evaluated. The evaluation results are shown in Table 3.

［グラビアコーティングへの適用の可能性］
（実施例９）
グラビアコーター（中島精機エンジニアリング株式会社（現・株式会社ユニオンテック）製）の液溜め（パン）に実施例１−１の塗工液を入れ、グラビアロールを一定速度で回転させた。アルミニウム箔をグラビアロールに接触させ、回転方向と逆方向にアルミ箔を搬送してコーティングを行った。このとき、グラビアロールの未彫刻部（被覆層が形成されない部分に対応する）および彫刻部（被覆層が形成される部分に対応する）にはスジの発生は観察されなかった（図４）。これより、本塗工液はカーボンブラックの分散性が良好であり、グラビアコーティングへの適用が可能であることがわかる。
（比較例９）
ポリ−Ｎ−ビニルアセトアミドの添加量を０．０５質量部（被覆層中の含有率：０．０５０質量％）に変更した以外は実施例１−１と同様にして作製した塗工液を、上記グラビアコーターの液溜めに入れ、実施例９と同様にグラビアロールを一定速度で回転させた。このとき（アルミニウム箔をグラビアロールに接触させていない状態）、グラビアロールの未彫刻部にはスジの発生が観察された（図５）。
このスジの発生は、ポリ−Ｎ−ビニルアセトアミドの添加量が少ないためにアセチレンブラックの分散性が悪くなり、凝集物が形成されたことによるものと推測される。なお、グラビアロールの彫刻部にはスジの発生が観察されなかったが、これは彫刻部に存在する微小な窪み（塗工液が保持される部分）に凝集物が入り込み、スジの発生が起こりにくくなり、肉眼的にもスジの発生が観察されにくくなったためと考えられる。これより、本塗工液はグラビアコーティングへは適用できないことがわかる。
[Possibility of application to gravure coating]
(Example 9)
The coating solution of Example 1-1 was placed in a liquid reservoir (bread) of a gravure coater (Nakajima Seiki Engineering Co., Ltd. (now Union Tech Co., Ltd.)) and the gravure roll was rotated at a constant speed. The aluminum foil was brought into contact with a gravure roll, and the aluminum foil was conveyed in the direction opposite to the rotating direction for coating. At this time, no streak was observed in the unengraved portion (corresponding to the portion where the coating layer is not formed) and the engraved portion (corresponding to the portion where the coating layer is formed) of the gravure roll (FIG. 4). From this, it is understood that the present coating liquid has good dispersibility of carbon black and can be applied to gravure coating.
(Comparative Example 9)
A coating liquid prepared in the same manner as in Example 1-1, except that the addition amount of poly-N-vinylacetamide was changed to 0.05 part by mass (content in the coating layer: 0.050% by mass), It was placed in the liquid reservoir of the gravure coater and the gravure roll was rotated at a constant speed as in Example 9. At this time (a state in which the aluminum foil was not in contact with the gravure roll), generation of streaks was observed in the unengraved portion of the gravure roll (FIG. 5).
It is presumed that the generation of streaks was due to the fact that the dispersibility of acetylene black was deteriorated due to the small amount of poly-N-vinylacetamide added, and aggregates were formed. Although no streak was observed in the engraved part of the gravure roll, this was caused by the formation of streaks due to the inclusion of aggregates in the minute depressions (the part where the coating liquid is held) existing in the engraved part. This is considered to be because it became difficult and the occurrence of streaks was hardly observed with the naked eye. From this, it is understood that the main coating liquid cannot be applied to gravure coating.

Claims (9)

シート状の導電性基材の片面または両面に被覆層が形成された蓄電デバイス用集電体であって、
前記被覆層は粉体状炭素材料、モノマ単位としてフッ化ビニリデンを含む重合体およびフッ素非含有ビニル系重合体を含み、
前記フッ素非含有ビニル系重合体は、Ｎ−ビニルアセトアミドおよびＮ−ビニルアセトアミド誘導体、ビニルアルコールおよびビニルアルコール誘導体、ビニルピロリドンおよびビニルピロリドン誘導体、ならびに酢酸ビニルおよび酢酸ビニル誘導体からなる群から選ばれる１種をモノマ単位とする単独重合体、または前記の群から選ばれる１種以上をモノマ単位として含む共重合体であり、
前記被覆層中の前記フッ素非含有ビニル系重合体の含有率が０．０９９〜５．０質量％であることを特徴とする蓄電デバイス用集電体。 A current collector for an electricity storage device in which a coating layer is formed on one or both sides of a sheet-shaped conductive base material,
The coating layer contains a powdered carbon material, a polymer containing vinylidene fluoride as a monomer unit and a non-fluorine-containing vinyl polymer,
The fluorine-free vinyl polymer is one selected from the group consisting of N-vinylacetamide and N-vinylacetamide derivatives, vinyl alcohol and vinyl alcohol derivatives, vinylpyrrolidone and vinylpyrrolidone derivatives, and vinyl acetate and vinyl acetate derivatives. Is a homopolymer having a monomer unit, or a copolymer containing at least one selected from the above group as a monomer unit,
The current collector for an electricity storage device, wherein the content of the fluorine-free vinyl polymer in the coating layer is 0.099 to 5.0% by mass. 前記被覆層中の前記粉体状炭素材料の含有率が２０．０〜５０．０質量％である請求項１に記載の蓄電デバイス用集電体。   The current collector for an electricity storage device according to claim 1, wherein the content of the powdery carbon material in the coating layer is 20.0 to 50.0 mass%. 前記導電性基材一面当たりの前記被覆層の目付量が０．１〜５．０ｇ／ｍ２である請求項１または２に記載の蓄電デバイス用集電体。 The current collector for an electricity storage device according to claim 1 or 2, wherein a basis weight of the coating layer per one surface of the conductive base material is 0.1 to 5.0 g / m 2 . 請求項１〜３のいずれか一項に記載の蓄電デバイス用集電体を備えたリチウムイオン二次電池用電極。   An electrode for a lithium ion secondary battery, comprising the current collector for an electricity storage device according to claim 1. 請求項１〜３のいずれか一項に記載の蓄電デバイス用集電体を備えたリチウムイオン二次電池。   A lithium ion secondary battery comprising the current collector for an electricity storage device according to claim 1. 溶媒中に粉体状炭素材料、モノマ単位としてフッ化ビニリデンを含む重合体およびフッ素非含有ビニル系重合体が溶解または分散した塗工液を調製する工程、
前記調製した塗工液をシート状の導電性基材の片面または両面に塗布する工程、および
前記塗布した塗工液を乾燥させる工程を有し、
前記フッ素非含有ビニル系重合体は、Ｎ−ビニルアセトアミドおよびＮ−ビニルアセトアミド誘導体、ビニルアルコールおよびビニルアルコール誘導体、ビニルピロリドンおよびビニルピロリドン誘導体、ならびに酢酸ビニルおよび酢酸ビニル誘導体からなる群から選ばれる１種をモノマ単位とする単独重合体、または前記の群から選ばれる１種以上をモノマ単位として含む共重合体であり、
前記塗工液中の前記粉体状炭素材料、前記フッ化ビニリデンを含む重合体および前記フッ素非含有ビニル系重合体の合計の含有率が２〜１５質量％であり、
前記粉体状炭素材料、前記フッ化ビニリデンを含む重合体および前記フッ素非含有ビニル系重合体の合計質量に対する該フッ素非含有ビニル系重合体の質量割合が０．０９９〜５．０質量％であることを特徴とする蓄電デバイス用集電体の製造方法。 Powdery carbon material in a solvent, a step of preparing a coating solution in which a polymer containing vinylidene fluoride as a monomer unit and a fluorine-free vinyl polymer are dissolved or dispersed,
A step of applying the prepared coating liquid on one or both sides of a sheet-shaped conductive substrate, and a step of drying the applied coating liquid,
The fluorine-free vinyl polymer is one selected from the group consisting of N-vinylacetamide and N-vinylacetamide derivatives, vinyl alcohol and vinyl alcohol derivatives, vinylpyrrolidone and vinylpyrrolidone derivatives, and vinyl acetate and vinyl acetate derivatives. Is a homopolymer having a monomer unit, or a copolymer containing at least one selected from the above group as a monomer unit,
The total content of the powdery carbon material, the vinylidene fluoride-containing polymer and the fluorine-free vinyl polymer in the coating liquid is 2 to 15% by mass,
The mass ratio of the fluorine-free vinyl-based polymer to the total mass of the powdery carbon material, the vinylidene fluoride-containing polymer and the fluorine-free vinyl-based polymer is 0.099 to 5.0% by mass. A method for manufacturing a current collector for an electricity storage device, which is characterized by the following. 前記溶媒が水またはＮ−メチル−２−ピロリドンである請求項６に記載の蓄電デバイス用集電体の製造方法。   The method for producing a current collector for an electricity storage device according to claim 6, wherein the solvent is water or N-methyl-2-pyrrolidone. 溶媒中に粉体状炭素材料、モノマ単位としてフッ化ビニリデンを含む重合体およびフッ素非含有ビニル系重合体を含み、
前記フッ素非含有ビニル系重合体は、Ｎ−ビニルアセトアミドおよびＮ−ビニルアセトアミド誘導体、ビニルアルコールおよびビニルアルコール誘導体、ビニルピロリドンおよびビニルピロリドン誘導体、ならびに酢酸ビニルおよび酢酸ビニル誘導体からなる群から選ばれる１種をモノマ単位とする単独重合体、または前記の群から選ばれる１種以上をモノマ単位として含む共重合体であり、
前記塗工液中の前記粉体状炭素材料、前記フッ化ビニリデンを含む重合体および前記フッ素非含有ビニル系重合体の合計の含有率が２〜１５質量％であり、
前記粉体状炭素材料、前記フッ化ビニリデンを含む重合体および前記フッ素非含有ビニル系重合体の合計質量に対する該フッ素非含有ビニル系重合体の質量割合が０．０９９〜５．０質量％であることを特徴とする蓄電デバイス用集電体を製造するための塗工液。 A powdery carbon material in a solvent, a polymer containing vinylidene fluoride as a monomer unit and a fluorine-free vinyl-based polymer,
The fluorine-free vinyl polymer is one selected from the group consisting of N-vinylacetamide and N-vinylacetamide derivatives, vinyl alcohol and vinyl alcohol derivatives, vinylpyrrolidone and vinylpyrrolidone derivatives, and vinyl acetate and vinyl acetate derivatives. Is a homopolymer having a monomer unit, or a copolymer containing at least one selected from the above group as a monomer unit,
The total content of the powdery carbon material, the vinylidene fluoride-containing polymer and the fluorine-free vinyl polymer in the coating liquid is 2 to 15% by mass,
The mass ratio of the fluorine-free vinyl-based polymer to the total mass of the powdery carbon material, the vinylidene fluoride-containing polymer and the fluorine-free vinyl-based polymer is 0.099 to 5.0% by mass. A coating liquid for producing a current collector for an electricity storage device, which is characterized by being present. 前記溶媒が水またはＮ−メチル−２−ピロリドンである請求項８に記載の蓄電デバイス用集電体を製造するための塗工液。
The coating liquid for producing a current collector for an electricity storage device according to claim 8, wherein the solvent is water or N-methyl-2-pyrrolidone.
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