JPH11317222A - Production of negative electrode for nonaqueous electrolyte secondary battery - Google Patents

Production of negative electrode for nonaqueous electrolyte secondary battery

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Publication number
JPH11317222A
JPH11317222A JP10134284A JP13428498A JPH11317222A JP H11317222 A JPH11317222 A JP H11317222A JP 10134284 A JP10134284 A JP 10134284A JP 13428498 A JP13428498 A JP 13428498A JP H11317222 A JPH11317222 A JP H11317222A
Authority
JP
Japan
Prior art keywords
negative electrode
film
secondary battery
electrolyte secondary
aqueous electrolyte
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP10134284A
Other languages
Japanese (ja)
Other versions
JP3621257B2 (en
Inventor
Masayuki Takamori
雅之 高森
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Eneos Corp
Original Assignee
Japan Energy Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Japan Energy Corp filed Critical Japan Energy Corp
Priority to JP13428498A priority Critical patent/JP3621257B2/en
Publication of JPH11317222A publication Critical patent/JPH11317222A/en
Application granted granted Critical
Publication of JP3621257B2 publication Critical patent/JP3621257B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • 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

PROBLEM TO BE SOLVED: To improve the density of a negative electrode after compaction of a negative electrode using a flake-like negative electrode active material. SOLUTION: This production method is to produce a negative electrode for a nonaqueous electrolyte secondary battery which comprises a group of electrode plates consisting of both a positive electrode capable of storing and releasing lithium and the negative electrode having a principal constituent of a carbon material capable of storing and releasing lithium via a separator and a nonaqueous electrolyte with the carbon material constituting the negative electrode plate being composed of flake-like graphite. In this case, slurry obtained by mixing the flake-like graphite, a binder, a conductive agent and a plasitizer, in a solvent, is applied on a carrier film to obtain a cast film, which is softened by heating using a preheater, and the thermally softened film is passed through cooled rolling mill rolls for compaction. The film is deprived of heat in concurrence with compaction and the binder in the softened film is solidified to suppress rebound phenomenon.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は非水電解液二次電池
に関するものであり、特には鱗片状負極活物質を使用す
る負極において高エネルギー密度の向上のための負極製
造方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolyte secondary battery, and more particularly to a method for producing a negative electrode using a flaky negative electrode active material for improving high energy density.

【０００２】[0002]

【従来の技術】リチウム２次電池に代表される非水電解
液二次電池の基本構成は、正極及び負極並びに両電極の
間に介在せしめられるセパレータ（電解質）である。2. Description of the Related Art The basic structure of a non-aqueous electrolyte secondary battery represented by a lithium secondary battery is a positive electrode, a negative electrode, and a separator (electrolyte) interposed between both electrodes.

【０００３】以下、ポリマー電池を例に説明するが、本
発明はこれにより何ら制限されるものでなく、例えば、
液体系のリチウム二次電池にも適用できるものである。
このうち、正極及び負極は、活物質、導電材、結着材、
分散媒および必要に応じ（ポリマー系では）可塑剤から
構成されるスラリーを金属箔、金属メッシュ等の集電体
に塗工したものを使用する。Hereinafter, a polymer battery will be described as an example. However, the present invention is not limited to this.
The present invention can be applied to a liquid lithium secondary battery.
Among them, the positive electrode and the negative electrode are active material, conductive material, binder,
A slurry composed of a dispersion medium and, if necessary (in the case of a polymer system), a plasticizer is applied to a current collector such as a metal foil or a metal mesh.

【０００４】従来より、非水電解液二次電池において
は、正極活物質にコバルト酸リチウム（ＬｉＣｏＯ
2 ）、ニッケル酸リチウム（ＬｉＮｉＯ2 ）、リチウム
マンガン複合酸化物（ＬｉＭｎ2 Ｏ4 ）、二硫化モリブ
デン（ＭｏＳ2 ）、二硫化チタン（ＴｉＳ2 ）、二酸化
マンガン（ＭｎＯ2 ）、五硫化バナジウム（Ｖ2 Ｏ5 ）
などの遷移金属硫化物、もしくは酸化物が用いられてい
る。一方、負極活物質には、金属リチウム、リチウム−
アルミニウム合金やリチウム−ウッド合金などの金属材
料とともに、近年では、リチウムイオンの吸蔵・放出が
可能な非金属性材料、例えば天然黒鉛、人造黒鉛やこれ
らより結晶化度の低い非晶質カーボンなどの炭素材料が
用いられている。さらに、リチウムイオンの吸蔵・放出
が可能な新規な非金属性材料として、酸化鉄（ＦｅＯ2
等）、酸化タングステン（ＷＯ2 ）などの金属化合物、
あるいは各種の無機層状化合物（ＬｉＮ3 、ＢＣ2 Ｎ
等）、高分子化合物（ポリチオフェン、ポリアセチレン
等）などの負極活物質が提案されている。Conventionally, in non-aqueous electrolyte secondary batteries, lithium cobalt oxide (LiCoO) has been used as a positive electrode active material.
2 ), lithium nickelate (LiNiO 2 ), lithium manganese composite oxide (LiMn 2 O 4 ), molybdenum disulfide (MoS 2 ), titanium disulfide (TiS 2 ), manganese dioxide (MnO 2 ), vanadium pentasulfide ( V 2 O 5 )
Transition metal sulfides or oxides are used. On the other hand, as the negative electrode active material, metallic lithium, lithium-
Along with metal materials such as aluminum alloys and lithium-wood alloys, in recent years, nonmetallic materials capable of occluding and releasing lithium ions, such as natural graphite, artificial graphite and amorphous carbon having a lower degree of crystallinity than these, have been developed. Carbon materials are used. Further, as a new nonmetallic material capable of inserting and extracting lithium ions, iron oxide (FeO 2
Metal compounds such as tungsten oxide (WO 2 ),
Alternatively, various inorganic layered compounds (LiN 3 , BC 2 N
And the like, and a negative electrode active material such as a polymer compound (polythiophene, polyacetylene, etc.) has been proposed.

【０００５】導電材としては、例えば、グラファイトカ
ーボン、アセチレンブラック等が挙げられる。結着材と
しては、フッ素系樹脂が良好で、その他、ポリテトラフ
ルオロエチレン（ＰＴＦＥ）、ポリフッ化ビニリデン
（ＰＶＤＦ）、ＰＶＤＦ系共重合体等が挙げられる。分
散媒としては、結着材が溶解可能な有機溶媒が適切で、
例えば、アセトン、メチルエチルケトン（ＭＥＫ）、Ｎ
−メチルピロリゾン（ＮＭＰ）等が挙げられる。可塑剤
は、スラリーを成膜した後に有機溶媒等で除去可能な有
機系物質が有効であり、例えば、フタル酸ジブチル（Ｄ
ＢＰ）等が挙げられる。集電体には、パンチングメタ
ル、エキスパンドメタルもまた有効である。[0005] Examples of the conductive material include graphite carbon and acetylene black. As the binder, a fluorine-based resin is preferable, and other examples include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and a PVDF-based copolymer. As the dispersion medium, an organic solvent in which the binder can be dissolved is appropriate,
For example, acetone, methyl ethyl ketone (MEK), N
-Methylpyrrolizone (NMP) and the like. As the plasticizer, an organic substance that can be removed with an organic solvent or the like after the slurry is formed is effective. For example, dibutyl phthalate (D
BP) and the like. Punching metal and expanded metal are also effective for the current collector.

【０００６】塗工に必要なスラリーは、上記活物質、導
電材、結着材、分散媒および可塑剤を所定の比率で溶剤
に溶かして混練して調製する。調製には、ホモジナイザ
ー、ボールミル、サンドミル、ロールミル、遊星型混練
機等の混練分散機が用いられる。また、集電体への塗工
には、グラビアコート、ブレードコート、コンマコー
ト、ディップコート等の各塗工方法が用いられる。[0006] The slurry required for coating is prepared by dissolving the above-mentioned active material, conductive material, binder, dispersion medium and plasticizer in a solvent at a predetermined ratio and kneading them. For the preparation, a kneading and dispersing machine such as a homogenizer, a ball mill, a sand mill, a roll mill, and a planetary kneader are used. In addition, a coating method such as gravure coating, blade coating, comma coating, and dip coating is used for coating the current collector.

【０００７】また、電解液にはリチウム塩を溶解したプ
ロピレンカーボネイト（ＰＣ）、エチレンカーボネイト
（ＥＣ）、ガンマブチロラクトン（ＧＢＬ）、ジエチル
カーボネイト（ＤＥＣ）、２−メチルテトラヒドロフラ
ン（ＭＴＨＦ）などがよく使われている。As the electrolyte, propylene carbonate (PC), ethylene carbonate (EC), gamma-butyrolactone (GBL), diethyl carbonate (DEC), 2-methyltetrahydrofuran (MTHF) and the like in which a lithium salt is dissolved are often used. ing.

【０００８】近年、これらの正・負極及び電解液を用い
た非水電解液二次電池の中で放電平均電圧が約３．６Ｖ
の高電圧を示し、高エネルギー密度を有する電池系とし
て各種電子機器用電源として注目を集めている。これら
の電池系の正極活物質には、ＬｉＣｏＯ2 、ＬｉＮｉＯ
2 やＬｉＭｎ2 Ｏ4 などのリチウム複合酸化物が用いら
れており、負極活物質には黒鉛質や非晶質の炭素材料が
用いられている。In recent years, among non-aqueous electrolyte secondary batteries using these positive / negative electrodes and electrolyte, the average discharge voltage is about 3.6V.
It has attracted attention as a power source for various electronic devices as a battery system having a high energy density. The positive electrode active materials of these battery systems include LiCoO 2 , LiNiO
Lithium composite oxides such as 2 and LiMn 2 O 4 are used, and a graphite or amorphous carbon material is used as a negative electrode active material.

【０００９】ところで、正極、負極、及びセパレータ物
質は、その組立に先立って、成膜工程において、バック
材とも呼ばれるキャリアーフィルム上にそれぞれスラリ
ー状態で塗工され、乾燥され、個別に巻き取られ、正極
フィルム、負極フィルム及びセパレータフィルムを構成
する。Prior to the assembly, the positive electrode, the negative electrode, and the separator material are each coated in a slurry state on a carrier film, also called a backing material, in a film forming step, dried, and individually wound up. Construct a positive electrode film, a negative electrode film and a separator film.

【００１０】詳しくは、負極の場合、上述した成膜工程
において、非鱗片状負極活物質を用いる場合には、負極
は電池製造工程において、以下のようなプロセスを経て
圧密化され、その活物質密度は０．８４ｇ／ｃｍ3 以下
である。 ミキシング：活剤５６（ｗｔ％）、結着材１６％、カ
ーボン３％、ＤＢＰ２５％を所定の溶材に混合し、スラ
リーを製造する。 キャスティング：スラリーをキャリアーフィルム上に
塗工する。 圧密：キャストフィルムを圧延ローラー間に通し、所
定条件（ローラー表面温度：９０〜１５０℃、搬送速
度：１〜１０ｍ／ｍｉｎ、圧下量：キャストフィルム全
厚に対して−１０〜−６０％）で圧密する。More specifically, in the case of a negative electrode, in the case where a non-flaky negative electrode active material is used in the above-mentioned film forming step, the negative electrode is compacted through the following process in the battery manufacturing process, The density is 0.84 g / cm 3 or less. Mixing: The active agent 56 (wt%), the binder 16%, the carbon 3%, and the DBP 25% are mixed with a predetermined material to produce a slurry. Casting: The slurry is applied on a carrier film. Consolidation: The cast film is passed between rolling rollers, and under predetermined conditions (roller surface temperature: 90 to 150 ° C., conveyance speed: 1 to 10 m / min, reduction amount: −10 to −60% based on the total thickness of the cast film). Consolidate.

【００１１】[0011]

【発明が解決しようとする課題】現在、安価な天然黒鉛
や人造黒鉛が負極活物質に用いられるが、ほとんどの形
態が粉砕により鱗片状である。鱗片状粒子は平面部と側
面部からなり、平面部は炭素六角網からなり、結晶配列
は平面部と平行に配列している。この材料を負極活物質
に用いると粒子の形状異方性により、圧密化後の負極密
度は０．８４ｇ／ｃｍ3 以下となる。高エネルギー密度
の向上のためには、圧密化後の負極密度を向上する必要
がある。本発明の課題は、鱗片状負極活物質を使用する
負極において圧密化後の負極密度を向上することにあ
る。At present, inexpensive natural graphite and artificial graphite are used for the negative electrode active material, but most of them are scaly by pulverization. The scaly particles are composed of a plane part and a side part, the plane part is composed of a hexagonal carbon network, and the crystal arrangement is arranged parallel to the plane part. When this material is used for the negative electrode active material, the density of the negative electrode after compaction becomes 0.84 g / cm 3 or less due to the shape anisotropy of the particles. In order to improve the high energy density, it is necessary to increase the density of the negative electrode after compaction. An object of the present invention is to improve the density of a negative electrode after compaction in a negative electrode using a flaky negative electrode active material.

【００１２】[0012]

【課題を解決するための手段】本発明者は、上記圧密化
後の負極密度の低下は、圧延ロールを通過した溶融フィ
ルムが負極活物質の形状異方性に起因するバネ効果によ
り再び膨張することによることを究明した。図３に示す
ように、例えば活剤５６％、結着材１６％、カーボン３
％、ＤＢＰ２５％を所定の溶剤に混合して得たスラリー
をキャリアーフィルム上に塗工したキャストフィルムを
圧延ローラー間に通し、所定条件（ローラー表面温度：
９０〜１５０℃、搬送速度：１〜１０ｍ／ｍｉｎ、圧下
量：キャストフィルム全厚に対して−１０〜−６０％）
で圧密する場合、圧延ローラー通過後、矢印で示すよう
に、負極活物質の形状異方性に起因するバネ効果により
キャストフィルム再び膨張する。The inventor of the present invention has found that the decrease in the density of the negative electrode after the compaction is caused by the fact that the molten film that has passed through the rolling roll expands again due to the spring effect caused by the shape anisotropy of the negative electrode active material. I decided to do something. As shown in FIG. 3, for example, active agent 56%, binder 16%, carbon 3
% And DBP 25% in a predetermined solvent, and a cast film obtained by coating a slurry on a carrier film is passed through a rolling roller under predetermined conditions (roller surface temperature:
90-150 ° C., conveying speed: 1-10 m / min, rolling reduction: -10 to -60% based on the total thickness of the cast film)
In the case of compacting, the cast film expands again by the spring effect caused by the shape anisotropy of the negative electrode active material as shown by the arrow after passing through the rolling roller.

【００１３】本発明者は、このフィルムの再膨張（リバ
ウンド）現象を抑制するためには、予熱した負極フィル
ムを、冷却したプレスローラー間を通すことが有効であ
ることを見いだした。かくして、本発明は、リチウムの
吸蔵・放出が可能な正極と、セパレータを介してリチウ
ムの吸蔵・放出が可能な炭素材を主成分とする負極との
極板群を備え、非水電解液を用い、そして該負極極板を
構成する炭素材が鱗片状黒鉛から成る非水電解液二次電
池の負極製造方法において、予熱した負極フィルムを、
冷却したプレスローラー間を通すことにより圧密加工す
ることを特徴とする非水電解液二次電池の負極製造方法
を提供する。The present inventor has found that it is effective to pass a preheated negative electrode film between cooled press rollers in order to suppress the re-expansion (rebound) phenomenon of the film. Thus, the present invention comprises an electrode plate group of a positive electrode capable of inserting and extracting lithium and a negative electrode mainly composed of a carbon material capable of inserting and extracting lithium through a separator. Used, and in the method of manufacturing a negative electrode of a non-aqueous electrolyte secondary battery in which the carbon material constituting the negative electrode plate is made of flaky graphite, a preheated negative electrode film,
A method for producing a negative electrode of a non-aqueous electrolyte secondary battery, comprising performing consolidation by passing between cooled press rollers.

【００１４】より特定的には、本発明は、リチウムの吸
蔵・放出が可能な正極と、セパレータを介してリチウム
の吸蔵・放出が可能な炭素材を主成分とする負極との極
板群を備え、非水電解液を用い、そして該負極極板を構
成する炭素材が鱗片状黒鉛から成る非水電解液二次電池
の負極製造方法において、鱗片状黒鉛粒子、結着材、導
電剤、可塑剤を溶剤に混合して得たスラリーをキャリア
ーフィルム上に塗工したキャストフィルムをプレヒータ
ーにより９０〜１５０℃に加熱して軟化状態とし、熱軟
化フィルムを０〜１５℃の温度に冷却された圧延ロール
間に通すことにより圧密加工することを特徴とする非水
電解液二次電池の負極製造方法を提供する。More specifically, the present invention provides an electrode plate group comprising a positive electrode capable of absorbing and releasing lithium and a negative electrode mainly composed of a carbon material capable of absorbing and releasing lithium through a separator. In the method for producing a negative electrode of a non-aqueous electrolyte secondary battery comprising a nonaqueous electrolytic solution and a carbon material constituting the negative electrode plate made of flaky graphite, flaky graphite particles, a binder, a conductive agent, A cast film obtained by coating a slurry obtained by mixing a plasticizer with a solvent on a carrier film is heated to 90 to 150 ° C by a preheater to be in a softened state, and the heat-softened film is cooled to a temperature of 0 to 15 ° C. To provide a method for producing a negative electrode of a non-aqueous electrolyte secondary battery, characterized in that the negative electrode is compacted by being passed between rolling rolls.

【００１５】ここで、「鱗片状黒鉛」とは、粒度分布で
測定された平均粒径Ｄと、粒子厚みＴの比Ｔ／Ｄが１／
３以下の黒鉛を云う。Here, “flaky graphite” means that the ratio T / D of the average particle diameter D measured by the particle size distribution to the particle thickness T is 1 / D.
3 or less graphite.

【００１６】[0016]

【発明の実施の形態】本発明に従えば、例えば、活剤
（鱗片状黒鉛粒子）５０〜６０％、結着材（例：フッ素
系樹脂）１０〜２０％、導電剤（例：カーボン）１〜５
％、可塑剤（例：ＤＢＰ）２０〜３０％を所定の溶剤
（例：アセトン）に混合して得たスラリーをキャリアー
フィルム上に塗工したキャストフィルムは、図１に示す
ように、フィルム行路の上面及び下面に沿って配置され
る長尺のプレヒーターにより９０〜１５０℃に加熱され
軟化状態となる。熱軟化フィルムは冷却圧延ロール間に
通すことにより圧密化され、同時に熱を奪われることに
より、軟化していたフィルム中の結着材が固化するた
め、リバウンド現象が抑制できる。DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the present invention, for example, 50 to 60% of an active agent (flaky graphite particles), 10 to 20% of a binder (eg, a fluororesin), and a conductive agent (eg, carbon) 1-5
%, A plasticizer (eg, DBP) 20 to 30% mixed with a predetermined solvent (eg, acetone), and a slurry obtained by coating the slurry on a carrier film, as shown in FIG. Is heated to 90 to 150 ° C. by a long pre-heater disposed along the upper and lower surfaces of the substrate to be in a softened state. The heat-softened film is compacted by passing it between the cooling rolls, and at the same time, the heat is deprived, so that the binder in the softened film is solidified, so that the rebound phenomenon can be suppressed.

【００１７】フィルム中の結着材が固化するためには、
冷却ロールの温度は、−３０〜１５℃、好ましくは０〜
１５℃の範囲である。冷却ロール圧下量は、所要の圧密
効果を得るために−１０〜−６０％、好ましくは−２０
〜−４０％、代表的に−３０％前後である。ローラー回
転数を与えられた負極フィルム組成及び圧延条件におい
て、最大の圧密後密度を与えるように最適のローラー回
転数範囲を選択する必要がある。ローラー速度を上げ過
ぎるとフィルムの熱が冷めずに圧延ロールを通過するた
め、リバウンドを抑制し得ず、他方ローラー速度を下げ
過ぎると圧延ロールに入る前にフィルムが冷めてしま
い、圧密効果が得られない。In order for the binder in the film to solidify,
The temperature of the cooling roll is -30 to 15C, preferably 0 to 15C.
It is in the range of 15 ° C. The amount of reduction of the cooling roll is -10% to -60%, preferably -20%, in order to obtain a required consolidation effect.
-40%, typically around -30%. For the negative electrode film composition and the rolling conditions given the roller rotation speed, it is necessary to select an optimum roller rotation speed range so as to give the maximum density after consolidation. If the roller speed is too high, the heat of the film passes through the rolling roll without cooling, so that rebound cannot be suppressed.On the other hand, if the roller speed is too low, the film cools before entering the rolling roll, and the consolidation effect is obtained. I can't.

【００１８】[0018]

【実施例】負極スラリー組成は、活剤として鱗片状黒鉛
粒子５６％、結着剤としてフッ素系樹脂１６％、導電剤
として導電性カーボン３％、可塑材としてＤＢＰ２５
％、そして溶剤としてアセトンを用いて、粘度：０．８
Ｐａ．ｓに調整したスラリーを調製した。EXAMPLE The negative electrode slurry composition was as follows: 56% of flake graphite particles as an active agent, 16% of a fluorinated resin as a binder, 3% of conductive carbon as a conductive agent, and DBP25 as a plasticizer.
%, Using acetone as solvent, viscosity: 0.8
Pa. s was prepared.

【００１９】このスラリーをＰＥＴフィルムに塗工後、
約１００℃にプレヒートし、圧延ロール（冷却ロール温
度：１０℃、圧下量：−３０％）に通し、ローラー回転
数を０．５ｒｐｍ〜６．５ｒｐｍとふった場合、３．４
ｒｐｍにて活剤密度０．９５ｇ／ｃｍ3 が得られた。ロ
ーラー回転数と圧密後密度との関係を図２に示す。与え
られたスラリー組成及び圧延条件において、最大の圧密
後密度を与える最適のローラー回転数範囲が存在する。
この特定例では、最適のローラー回転数範囲は、１．７
〜５．０ｒｐｍ、好ましくは２．７〜３．８ｒｐｍであ
る。ローラー速度を上げ過ぎるとフィルムの熱が冷めず
に圧延ロールを通過するため、リバウンドを抑制し得
ず、ローラー速度を下げ過ぎると圧延ロールに入る前に
フィルムが冷めてしまい、圧密効果が得られない。After applying this slurry to a PET film,
When preheated to about 100 ° C. and passed through a rolling roll (cooling roll temperature: 10 ° C., reduction amount: −30%), and the roller rotation speed is changed to 0.5 rpm to 6.5 rpm, 3.4.
An active agent density of 0.95 g / cm 3 was obtained at rpm. FIG. 2 shows the relationship between the number of rotations of the roller and the density after consolidation. For a given slurry composition and rolling conditions, there is an optimum roller speed range that gives the maximum density after consolidation.
In this particular example, the optimal roller speed range is 1.7
To 5.0 rpm, preferably 2.7 to 3.8 rpm. If the roller speed is too high, the heat of the film will pass through the rolling rolls without cooling, so that rebound cannot be suppressed.If the roller speed is too low, the film will cool before entering the rolling rolls, and the consolidation effect will be obtained. Absent.

【００２０】この負極フィルムを用いて電池を作製した
結果、体積容量が従来の圧密方法を用いた場合に比べて
次の通り１３％向上することがわかった。 鱗片状黒鉛のグラム容量＝３２０ｍＡｈ／ｇ…（Ｘ） （Ｘ）活剤密度（０．９５ｇ／ｃｍ3 ）＝３０４ｍＡｈ
／ｃｍ3 ：本発明 （Ｘ）活剤密度（０．８４ｇ／ｃｍ3 ）＝２６９ｍＡｈ
／ｃｍ3 ：従来法（比較例） 体積容量改善率＝（３０４−２６９）／２６９×１００
＝１３．０％As a result of producing a battery using this negative electrode film, it was found that the volume capacity was improved by 13% as compared with the case where the conventional consolidation method was used, as follows. Gram capacity of flaky graphite = 320 mAh / g ... (X) (X) Active agent density (0.95 g / cm 3 ) = 304 mAh
/ Cm 3 : present invention (X) active agent density (0.84 g / cm 3 ) = 269 mAh
/ Cm 3 : Conventional method (comparative example) Volume capacity improvement rate = (304-269) / 269 × 100
= 13.0%

【００２１】[0021]

【発明の効果】以上の説明から明らかなように、本発明
は負極炭素材が粒度分布で測定された平均粒径Ｄと、粒
子厚みＴの比Ｔ／Ｄが１／３以下の鱗片状黒鉛であり、
この鱗片状黒鉛粒子を含んだ負極フィルムを前述のプレ
ス法で圧密加工したフィルムを用いた電池は、従来のプ
レス法で圧密加工したフィルムを用いた電池に比べて体
積容量が１３％改善されるため、現行工程に安価な天然
黒鉛を使用することができる。As is apparent from the above description, the present invention provides a flaky graphite in which the ratio T / D of the average particle diameter D measured by particle size distribution to the particle thickness T of the negative electrode carbon material is 1/3 or less. And
A battery using a film obtained by compacting the negative electrode film containing the flaky graphite particles by the above-described press method has a 13% improvement in volume capacity as compared with a battery using a film compacted by the conventional press method. Therefore, inexpensive natural graphite can be used in the current process.

【図面の簡単な説明】[Brief description of the drawings]

【図１】本発明に従う再膨張現象のない圧密方法の再膨
張現象を示す説明図である。FIG. 1 is an explanatory diagram showing a re-expansion phenomenon of a consolidation method without a re-expansion phenomenon according to the present invention.

【図２】実施例におけるローラー回転数と圧密後密度と
の関係を示すグラフである。FIG. 2 is a graph showing the relationship between the number of rotations of a roller and the density after consolidation in Examples.

【図３】現行圧密方法の再膨張現象を示す説明図であ
る。FIG. 3 is an explanatory diagram showing a re-expansion phenomenon of the current consolidation method.

Claims (2)

【特許請求の範囲】[Claims] 【請求項１】 リチウムの吸蔵・放出が可能な正極と、
セパレータを介してリチウムの吸蔵・放出が可能な炭素
材を主成分とする負極との極板群を備え、非水電解液を
用い、そして該負極極板を構成する炭素材が鱗片状黒鉛
から成る非水電解液二次電池の負極製造方法において、
予熱した負極フィルムを、冷却したプレスローラー間を
通すことにより圧密加工することを特徴とする非水電解
液二次電池の負極製造方法。A positive electrode capable of inserting and extracting lithium;
It is provided with an electrode group with a negative electrode mainly composed of a carbon material capable of inserting and extracting lithium through a separator, using a non-aqueous electrolyte, and the carbon material constituting the negative electrode plate is made of flaky graphite. In the method for producing a negative electrode of a non-aqueous electrolyte secondary battery comprising
A method for producing a negative electrode for a non-aqueous electrolyte secondary battery, comprising: consolidating a preheated negative electrode film by passing it between cooled press rollers. 【請求項２】 リチウムの吸蔵・放出が可能な正極と、
セパレータを介してリチウムの吸蔵・放出が可能な炭素
材を主成分とする負極との極板群を備え、非水電解液を
用い、そして該負極極板を構成する炭素材が鱗片状黒鉛
から成る非水電解液二次電池の負極製造方法において、
鱗片状黒鉛、結着材、導電剤及び可塑剤を溶剤に混合し
て得たスラリーをキャリアーフィルム上に塗工したキャ
ストフィルムをプレヒーターにより９０〜１５０℃に加
熱して軟化状態とし、該熱軟化フィルムを０〜１５℃の
温度に冷却された圧延ロール間に通すことにより圧密加
工することを特徴とする非水電解液二次電池の負極製造
方法。2. A positive electrode capable of inserting and extracting lithium, and
It is provided with an electrode group with a negative electrode mainly composed of a carbon material capable of inserting and extracting lithium through a separator, using a non-aqueous electrolyte, and the carbon material constituting the negative electrode plate is made of flaky graphite. In the method for producing a negative electrode of a non-aqueous electrolyte secondary battery comprising
A cast film obtained by coating a slurry obtained by mixing flaky graphite, a binder, a conductive agent and a plasticizer with a solvent on a carrier film is heated to 90 to 150 ° C. by a pre-heater to be in a softened state, A method for producing a negative electrode for a non-aqueous electrolyte secondary battery, wherein the softening film is passed through a rolling roll cooled to a temperature of 0 to 15 ° C. to perform consolidation.
JP13428498A 1998-04-30 1998-04-30 Method for producing negative electrode of non-aqueous electrolyte secondary battery Expired - Fee Related JP3621257B2 (en)

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JP2011181348A (en) * 2010-03-01 2011-09-15 Hitachi Engineering & Services Co Ltd Rolling press machine for secondary battery electrode material
JP2019527452A (en) * 2016-06-30 2019-09-26 南通沃▲徳▼材料科技有限公司Ｎａｎｔｏｎｇ Ｖｏｌｔａ Ｍａｔｅｒｉａｌｓ Ｌｔｄ． Method for preparing battery plate
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CN112909221A (en) * 2021-02-06 2021-06-04 湖南华兴新能源科技有限公司 Secondary baking process after rolling of cylindrical lithium ion battery cathode
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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011181348A (en) * 2010-03-01 2011-09-15 Hitachi Engineering & Services Co Ltd Rolling press machine for secondary battery electrode material
JP2019527452A (en) * 2016-06-30 2019-09-26 南通沃▲徳▼材料科技有限公司Ｎａｎｔｏｎｇ Ｖｏｌｔａ Ｍａｔｅｒｉａｌｓ Ｌｔｄ． Method for preparing battery plate
JP2021120954A (en) * 2016-06-30 2021-08-19 南通沃▲徳▼材料科技有限公司Nantong Volta Materials Ltd. Method of preparing battery electrode plate
CN110346727A (en) * 2019-06-12 2019-10-18 中兴高能技术有限责任公司 The method and lithium ion battery of monitoring, analysis anode slice of lithium ion battery rebound
CN110346728A (en) * 2019-06-12 2019-10-18 中兴高能技术有限责任公司 The method and lithium ion battery of monitoring, analysis lithium ion battery negative electrode rebound
CN110311105A (en) * 2019-06-20 2019-10-08 桑顿新能源科技(长沙)有限公司 A kind of cathode pole piece slurry and preparation method, cathode pole piece, lithium ion battery
CN112909221A (en) * 2021-02-06 2021-06-04 湖南华兴新能源科技有限公司 Secondary baking process after rolling of cylindrical lithium ion battery cathode
CN114759167A (en) * 2022-04-20 2022-07-15 江西安驰新能源科技有限公司 Manufacturing process of lithium battery positive plate
CN114784219A (en) * 2022-04-26 2022-07-22 江西安驰新能源科技有限公司 Manufacturing process of lithium battery negative plate
CN114975879A (en) * 2022-05-26 2022-08-30 湖南立方新能源科技有限责任公司 Method for determining compacted density of lithium ion battery pole piece

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