JP3016627B2 - Non-aqueous solvent secondary battery - Google Patents
Non-aqueous solvent secondary batteryInfo
- Publication number
- JP3016627B2 JP3016627B2 JP3160863A JP16086391A JP3016627B2 JP 3016627 B2 JP3016627 B2 JP 3016627B2 JP 3160863 A JP3160863 A JP 3160863A JP 16086391 A JP16086391 A JP 16086391A JP 3016627 B2 JP3016627 B2 JP 3016627B2
- Authority
- JP
- Japan
- Prior art keywords
- negative electrode
- lithium
- battery
- secondary battery
- aqueous solvent
- 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.)
- Expired - Fee Related
Links
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
Landscapes
- Secondary Cells (AREA)
- Battery Electrode And Active Subsutance (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、負極担持体として炭素
質材料を用いる非水溶媒二次電池に関し、とくにその改
良された負極に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous solvent secondary battery using a carbonaceous material as a negative electrode carrier, and more particularly to an improved negative electrode.
【０００２】[0002]
【従来の技術】近年、電子機器の発達に伴い、小形で軽
量、かつ、エネルギー密度が高く、さらに繰り返し充放
電が可能な二次電池の開発が要望されている。この種の
二次電池としては、負極活物質としてリチウム又はリチ
ウム合金を用い、正極活物質としてモリブデン、バナジ
ウム、チタン、ニオブなどの酸化物、硫化物、セレン化
物などを用いたものが知られている。2. Description of the Related Art In recent years, with the development of electronic equipment, there has been a demand for the development of a secondary battery that is small, lightweight, has a high energy density, and can be repeatedly charged and discharged. As this type of secondary battery, those using lithium or a lithium alloy as a negative electrode active material, and using oxides such as molybdenum, vanadium, titanium, and niobium, sulfides, and selenides as a positive electrode active material are known. I have.
【０００３】また最近では、高エネルギー密度を有する
マンガン酸化物のサイクル特性を改良・向上させたスピ
ネル型ＬｉＭｎ2 Ｏ4 や、他のリチウムマンガン酸化物
についての検討が活発に行われている。Recently, studies have been actively conducted on spinel-type LiMn 2 O 4 having improved and improved cycle characteristics of a manganese oxide having a high energy density and other lithium manganese oxides.
【０００４】一方、正極にはこれらマンガン酸化物と異
なる反応形態である層状化合物のインターカレーション
又はドーピング現象を利用した電極活物質が注目を集め
ている。これらの電極活物質は、充電、放電反応時にお
いて複雑な化学反応を起こさないことから、極めて優れ
た充放電サイクル特性を有することが期待される。中で
も炭素質材料を負極担持体とし、正極活物質としてＬｉ
ＣｏＯ2 ／ＬｉＮｉＯ2 やＴｉＳ2 、ＭｏＳ2 を用いた
電池系が提案されている。On the other hand, for the positive electrode, an electrode active material utilizing intercalation or doping of a layered compound having a different reaction form from these manganese oxides has attracted attention. Since these electrode active materials do not cause complicated chemical reactions during charge and discharge reactions, they are expected to have extremely excellent charge / discharge cycle characteristics. Among them, a carbonaceous material is used as a negative electrode carrier, and Li is used as a positive electrode active material.
Battery systems using CoO 2 / LiNiO 2 , TiS 2 , and MoS 2 have been proposed.
【０００５】これらの酸化物、硫化物、セレン化物を正
極活物質とし、リチウムを負極活物質とする電池系にお
いては、サイクルを繰り返すことによって負極活物質で
あるリチウムの溶解・析出反応が繰り返され、やがてリ
チウム金属上に針状のリチウムデンドライト析出物を形
成するという問題が生じる。そのため、電池系において
は、正極活物質中で充放電を繰り返すごとに徐々に進行
する結晶構造の崩れとともに、負極側におけるリチウム
デンドライトの生成と、負極上に析出したリチウムによ
る溶媒の分解反応によって電池寿命は規定され、５００
サイクル以上の寿命と、長期間にわたる信頼性を有する
電池の製造は非常に困難であった。In a battery system in which these oxides, sulfides, and selenides are used as a positive electrode active material and lithium is used as a negative electrode active material, the dissolution / precipitation reaction of lithium as the negative electrode active material is repeated by repeating the cycle. Eventually, a problem arises in that needle-like lithium dendrite deposits are formed on the lithium metal. Therefore, in the battery system, the battery structure gradually collapses with each repetition of charge / discharge in the positive electrode active material, lithium dendrite is generated on the negative electrode side, and the solvent is decomposed by the lithium deposited on the negative electrode to cause a solvent decomposition reaction. Life is specified, 500
It has been very difficult to manufacture a battery having a life of more than a cycle and a long-term reliability.
【０００６】また、充電の際に負極で起こるリチウムデ
ンドライトを軽減するよう、アルミニウム、鉛、ケイ素
などの金属とリチウムとの合金を、負極活物質とする検
討も進められている。しかし、この場合でも、充放電を
繰り返すと合金の粉末化が起こり、電池寿命はさほど延
びない。このような問題を回避するために、各種の有機
化合物を焼成した炭素質物にリチウム又はリチウムを主
体とするアルカリ金属を担持させて、負極を構成する二
次電池が試みられている。このような負極を用いること
により、リチウムデンドライトの析出が防止されてサイ
クル特性が向上し、かつ、金属リチウムを使用していな
いため、安全性についても向上してきている。Further, in order to reduce lithium dendrite generated at the negative electrode during charging, studies are being made on using an alloy of lithium with a metal such as aluminum, lead, or silicon as the negative electrode active material. However, even in this case, when charge and discharge are repeated, powdering of the alloy occurs, and the battery life is not significantly increased. In order to avoid such a problem, a secondary battery in which a negative electrode is formed by supporting lithium or an alkali metal mainly composed of lithium on a carbonaceous material obtained by firing various organic compounds has been attempted. By using such a negative electrode, precipitation of lithium dendrite is prevented and cycle characteristics are improved, and safety is also improved because metal lithium is not used.
【０００７】しかし、炭素質材料を負極活物質とした場
合、ＴｉＳ2 、ＭｏＳ2 などの金属カルコゲン化合物を
正極活物質として用いると起電力が小さい（１．０〜
１．２Ｖ）。そこで、正極活物質としては、３．５Ｖ程
度の平均作動電圧を示すＬｉＣｏＯ2 、ＬｉＮｉＯ2 、
ＬｉＣｏx Ｎｉ(1-x) Ｏ2 などが検討されてきている。However, when a carbonaceous material is used as the negative electrode active material, when a metal chalcogen compound such as TiS 2 or MoS 2 is used as the positive electrode active material, the electromotive force is small (from 1.0 to 1.0).
1.2V). Therefore, as the positive electrode active material, LiCoO 2 , LiNiO 2 , which exhibits an average operating voltage of about 3.5 V,
LiCo x Ni (1-x) O 2 and the like have been studied.
【０００８】これらの正極・負極活物質材料には、通
常、電池電極として使用する場合には、活物質の反応を
有効に進められるように導電剤を、また電極形状を維持
できるように結着剤を混合して使用している。たとえ
ば、円筒形電池においては、帯状の正極、セパレータ、
負極を渦巻状に形成した電極を使用している。この場
合、帯状の電極はステンレス、ニッケル、チタン、銅、
アルミニウムなどやこれらの金属の合金からなる基板上
に、活物質材料、導電剤、結着剤及び水又は有機溶媒の
混合物からなるスラリーを塗布乾燥し、圧延して作成さ
れる。このとき使用するスラリーは、だまが無く、すべ
てが均一に分散されていることが望ましい。[0008] When used as a battery electrode, a conductive agent is usually attached to these positive and negative electrode active material materials so that the reaction of the active material can be effectively promoted, and a binder is attached so that the electrode shape can be maintained. Agents are mixed and used. For example, in a cylindrical battery, a band-shaped positive electrode, a separator,
An electrode having a spirally formed negative electrode is used. In this case, the strip electrodes are made of stainless steel, nickel, titanium, copper,
A slurry made of a mixture of an active material, a conductive agent, a binder, and water or an organic solvent is applied on a substrate made of aluminum or the like or an alloy of these metals, dried, and rolled. It is desirable that the slurry used at this time be uniformly dispersed without any lumps.
【０００９】[0009]
【発明が解決しようとする課題】しかし、炭素質材料を
負極担持体として使用した電池は、充放電サイクル寿命
が短く、また、十分な容量維持率を得ることができなか
った。すなわち、電池電極の結着剤として従来から使用
されているポリテトラフルオロエチレンを用いると、充
放電サイクルの進行とともにリチウムと結着剤であるポ
リテトラフルオロエチレンとが反応してポリテトラフル
オロエチレンが分解し、負極体の結着能力を大幅に低下
させる。その結果、集電体と負極担持体との間の導電性
が損なわれ、電池内部抵抗を大幅に増加させる。また結
着能力の低下による負極担持体の脱落及び内部短絡など
の問題があった。また、従来から使用されてきた結着剤
であるエチレン−プロピレン−環状ジエンの三元共重合
体を用いたものは、負極担持体を覆うような結着形態を
とるため電池内部抵抗を大幅に増加させ、十分な特性を
得ることができなかった。However, a battery using a carbonaceous material as a negative electrode carrier has a short charge-discharge cycle life and cannot provide a sufficient capacity retention rate. That is, when polytetrafluoroethylene conventionally used as a binder for a battery electrode is used, lithium and polytetrafluoroethylene serving as a binder react with the progress of a charge / discharge cycle to form polytetrafluoroethylene. It decomposes and greatly reduces the binding capacity of the negative electrode body. As a result, the conductivity between the current collector and the negative electrode carrier is impaired, and the internal resistance of the battery is greatly increased. There were also problems such as falling off of the negative electrode carrier and internal short circuit due to a decrease in binding ability. In addition, those using a terpolymer of ethylene-propylene-cyclic diene, which is a binder used in the past, greatly reduce the internal resistance of the battery because it takes a binding form that covers the negative electrode carrier. Increased, and could not obtain sufficient properties.
【００１０】また、負極担持体は有機化合物を焼成した
り、気相法などにより作成されるが、このようにして作
成された負極担持体は活性であり、空気雰囲気中で保存
すると、表面に電池反応にとって有害な官能基（水酸基
やカルボニル基）が形成される。これらの官能基がある
と、充電時に負極担持体上で還元されたリチウム金属が
これらの官能基と反応を起こし、放電反応にこの分のリ
チウムが使用されないため、充放電効率が低下し、さら
に充放電サイクル数が減少するに至る。The negative electrode carrier is produced by baking an organic compound or by a gas phase method. The negative electrode carrier thus produced is active and, when stored in an air atmosphere, has a negative effect on the surface. A harmful functional group (hydroxyl group or carbonyl group) is formed for the battery reaction. When these functional groups are present, the lithium metal reduced on the negative electrode carrier during charging reacts with these functional groups, and this amount of lithium is not used in the discharging reaction, so that the charging / discharging efficiency is reduced. The number of charge / discharge cycles is reduced.
【００１１】本発明はかかる問題点を改善するためにな
されたもので、充放電効率が高く、充放電サイクル寿命
に優れた非水溶媒二次電池を提供しようとするものであ
る。The present invention has been made in order to solve such problems, and an object thereof is to provide a non-aqueous solvent secondary battery having high charge / discharge efficiency and excellent charge / discharge cycle life.
【００１２】[0012]
【課題を解決するための手段】すなわち本発明の非水溶
媒二次電池は、リチウム又はリチウムを主体とするアル
カリ金属を担持した炭素質材料からなる負極体と、セパ
レータと、リチウム含有複合酸化物を正極活物質とする
正極体とを、この順序で一体的に積層してなる発電要素
を具備する非水溶媒二次電池において、該負極体の結着
剤としてリチウムシリケートを用いることを特徴とす
る。That is, a non-aqueous solvent secondary battery according to the present invention comprises a negative electrode made of lithium or a carbonaceous material carrying lithium-based alkali metal, a separator, and a lithium-containing composite oxide. And a positive electrode body having a positive electrode active material, in a non-aqueous solvent secondary battery including a power generation element integrally laminated in this order, characterized in that lithium silicate is used as a binder for the negative electrode body. I do.
【００１３】本発明で用いられるリチウム含有複合酸化
物は、一般的に次のような方法で合成される。すなわ
ち、リチウムと、Ｃｏ、Ｎｉ、Ｆｅ又はＭｎから選ばれ
る１種又は２種以上の遷移金属の炭酸塩、硝酸塩、硫酸
塩、水酸化物などを出発原料として、これらを化学量論
比で混合し、焼成することによって得られる。なお、出
発原料としては炭酸塩が好ましい。焼成温度は出発原料
により多少異なるが、通常は６００〜１，０００℃の温
度範囲で、好ましくは６００〜８００℃の範囲である。The lithium-containing composite oxide used in the present invention is generally synthesized by the following method. That is, lithium and one or more transition metal carbonates, nitrates, sulfates, hydroxides, etc. selected from Co, Ni, Fe or Mn are used as starting materials and mixed at a stoichiometric ratio. And fired. In addition, carbonate is preferable as a starting material. The firing temperature varies somewhat depending on the starting materials, but is usually in the temperature range of 600 to 1,000 ° C, preferably in the range of 600 to 800 ° C.
【００１４】負極担持体である炭素質材料は、電池特性
の向上のために、好ましくは有機化合物を焼成してなる
炭素質材料を用いる。この炭素質材料の原料となる有機
化合物としては、通常使用されているものであれば特に
限定されるものではなく、フェノール樹脂、とくにノボ
ラック樹脂、ならびにポリアクリロニトリルなどを用い
ることができる。またこの炭素質材料としては、特願平
１−２８３０８６号に示すような有機化合物焼成体の特
性を有するものが、とくに好ましい。As the carbonaceous material as the negative electrode carrier, a carbonaceous material obtained by firing an organic compound is preferably used in order to improve battery characteristics. The organic compound serving as a raw material of the carbonaceous material is not particularly limited as long as it is a commonly used one, and a phenol resin, particularly a novolak resin, and polyacrylonitrile can be used. As the carbonaceous material, a material having the characteristics of an organic compound fired body as shown in Japanese Patent Application No. 1-283086 is particularly preferable.
【００１５】負極の結着剤として用いられる物質につい
て要求される性質は、リチウムと反応しないこと、電解
液と反応しないこと、電極乾燥温度で劣化しないこと、
活物質粒子を保持し、電気伝導性を失わないこと、電極
としての柔軟性を保てることなどである。The properties required for the material used as the binder of the negative electrode are that it does not react with lithium, does not react with the electrolyte, does not deteriorate at the electrode drying temperature,
The purpose is to retain the active material particles, not to lose the electric conductivity, and to maintain the flexibility as an electrode.
【００１６】本発明によるリチウムシリケートは、前記
の諸性質を満足し、さらに、乾燥後の性質として、水や
有機溶媒に不溶性であるほか、不燃性で、１，０００℃
までの耐熱性があり、強い接着力を示すなどの特徴があ
る。リチウムシリケートの組成は、ＳｉＯ2 ／Ｌｉ2 Ｏ
比がモル比で３．２〜７．８が好ましい。前述のモル比
がこの範囲内であれば、前記の諸性質がいずれも優れ、
本発明の結着剤として使用できる。The lithium silicate according to the present invention satisfies the above-mentioned various properties, and further, as a property after drying, is insoluble in water or an organic solvent, is nonflammable, and has a temperature of 1,000 ° C.
It has features such as high heat resistance and strong adhesive strength. The composition of the lithium silicate is SiO 2 / Li 2 O
The molar ratio is preferably 3.2 to 7.8. If the above molar ratio is within this range, all of the above properties are excellent,
It can be used as a binder of the present invention.
【００１７】また、リチウムシリケートは、カルボキシ
メチルセルロース又はその塩（以下、ＣＭＣという）、
メチルセルロース、ポリアクリル酸、ポリアクリル酸ナ
トリウム、ポリビニルアルコールなど水溶性高分子との
混合や、スチレンブタジエンゴムラテックス、アクリロ
ニトリルブタジエンゴムラテックス、クロロプレンラテ
ックスなどの合成ゴムラテックスとの混合が可能である
ため、水溶性高分子を用いて前記の電池電極の作成時に
適したスラリーを作ることが可能であり、さらに合成ゴ
ムラテックスを使用することによって、柔軟性に優れた
電極を作成することが可能となる。水溶性高分子を用い
た場合には、これらの物質の分解温度が約１２０〜２０
０℃であるため、使用した水溶性高分子の分解温度以上
に電極乾燥温度を上げても、リチウムシリケートがその
性質を維持し、電極として使用できる。The lithium silicate is carboxymethylcellulose or a salt thereof (hereinafter referred to as CMC),
Mixing with water-soluble polymers such as methyl cellulose, polyacrylic acid, sodium polyacrylate, and polyvinyl alcohol, and mixing with synthetic rubber latex such as styrene-butadiene rubber latex, acrylonitrile-butadiene rubber latex, and chloroprene latex are possible. It is possible to prepare a slurry suitable for preparing the battery electrode using a conductive polymer, and to use a synthetic rubber latex to prepare an electrode having excellent flexibility. When a water-soluble polymer is used, the decomposition temperature of these substances is about 120 to 20.
Since the temperature is 0 ° C., even if the electrode drying temperature is raised to a temperature higher than the decomposition temperature of the used water-soluble polymer, the lithium silicate maintains its properties and can be used as an electrode.
【００１８】電極中に含まれる結着剤の量は、電極性能
さえ維持できれば、なるべく少ない方がよい。結着剤の
量が多くなると、負極の内部抵抗が増加し、電池の重負
荷放電の能力を大幅に低下させるので好ましくない。し
かし、結着剤の量が極度に少ない場合には、電極の形状
を維持することが困難となり、活物質の脱落が起こり易
く、内部短絡の原因となる。本発明によるリチウムシリ
ケートの量は、負極活物質のかさ密度や粒径、粒子形状
により異なるが、１〜１０％程度が好ましい。The amount of the binder contained in the electrode is preferably as small as possible as long as the performance of the electrode can be maintained. An increase in the amount of the binder is not preferable because the internal resistance of the negative electrode increases and the heavy load discharging ability of the battery is significantly reduced. However, when the amount of the binder is extremely small, it becomes difficult to maintain the shape of the electrode, the active material is likely to fall off, and this causes an internal short circuit. The amount of the lithium silicate according to the present invention varies depending on the bulk density, particle size, and particle shape of the negative electrode active material, but is preferably about 1 to 10%.
【００１９】本発明の非水溶媒二次電池に用いられる非
水電解液の電解質としては、ＬｉＰＦ6 、ＬｉＣｌＯ
4 、ＬｉＢＦ4 、ＬｉＣＦ3 ＳＯ3 などのリチウム塩な
どが挙げられる。該電解液の溶媒としては、プロピレン
カーボネート、エチレンカーボネート、テトラヒドロフ
ラン、２−メチルテトラヒドロフラン、γ−ブチロラク
トン、１，２−ジメトキシエタンなどが挙げられる。こ
れらの溶媒は１種又は２種以上の混合物で用いることが
でき、とくに充放電サイクル寿命を長くする観点から、
プロピレンカーボネートと１，２−ジメトキシエタンと
の混合溶媒、エチレンカーボネートと２−メチルテトラ
ヒドロフランとの混合溶媒、エチレンカーボネートと
１，２−ジメトキシエタンとの混合溶媒、プロピレンカ
ーボネートとエチレンカーボネートとの混合溶媒が望ま
しい。The electrolyte of the non-aqueous electrolyte used in the non-aqueous solvent secondary battery of the present invention is LiPF 6 , LiClO 2
4 , lithium salts such as LiBF 4 and LiCF 3 SO 3 . Examples of the solvent for the electrolyte include propylene carbonate, ethylene carbonate, tetrahydrofuran, 2-methyltetrahydrofuran, γ-butyrolactone, 1,2-dimethoxyethane, and the like. These solvents can be used alone or in a mixture of two or more, and particularly from the viewpoint of extending the charge / discharge cycle life,
A mixed solvent of propylene carbonate and 1,2-dimethoxyethane, a mixed solvent of ethylene carbonate and 2-methyltetrahydrofuran, a mixed solvent of ethylene carbonate and 1,2-dimethoxyethane, and a mixed solvent of propylene carbonate and ethylene carbonate desirable.
【００２０】[0020]
【発明の効果】本発明の二次電池は、負極体の結着剤に
リチウムシリケートを用いることにより、リチウムと結
着剤とが反応することがなく、その結果、充放電サイク
ルを繰り返しても、集電体と負極担持体との間の導電性
を損なうことにより生ずる電池内部抵の増加、また結着
能力の低下による負極担持体の脱落、及び内部短絡を起
こさない。またリチウムシリケートは水溶性高分子や合
成ゴムラテックスと相溶性があるので、これらの水溶性
ないし水分散性高分子を用いて、前記の電池電極の作成
時に適したスラリーを作ることが可能であり、さらに合
成ゴムラテックスを使用して、柔軟性に優れた電極を作
成することが可能となる。さらに、水溶性高分子を用い
た場合には、これらの物質の分解温度が約１２０℃〜２
００℃付近であるため、使用した水溶性高分子の分解温
度以上に電極乾燥温度を上げても、リチウムシリケート
がその性質を維持しているため、充放電性能には関係し
ない水溶性高分子を分解除去できる。その上、従来から
課題であった負極担持体表面にある官能基も除去でき
る。それゆえ、充放電効率及び充放電サイクル寿命が向
上し、しかも電池性能が安定した非水溶媒二次電池を得
ることができる。According to the secondary battery of the present invention, since lithium silicate is used as a binder for the negative electrode body, lithium does not react with the binder, and as a result, even if charge / discharge cycles are repeated. In addition, an increase in the internal resistance of the battery caused by impairing the conductivity between the current collector and the negative electrode support, a drop of the negative electrode support due to a decrease in binding ability, and an internal short circuit do not occur. In addition, since lithium silicate is compatible with water-soluble polymers and synthetic rubber latex, it is possible to use these water-soluble or water-dispersible polymers to make a slurry suitable for preparing the battery electrode. In addition, it is possible to prepare an electrode having excellent flexibility by using a synthetic rubber latex. Further, when a water-soluble polymer is used, the decomposition temperature of these substances is about 120 ° C to 2 ° C.
Since the temperature is around 00 ° C., even if the electrode drying temperature is raised to a temperature higher than the decomposition temperature of the used water-soluble polymer, since the lithium silicate maintains its properties, the water-soluble polymer which is not related to the charge / discharge performance is removed. Can be decomposed and removed. In addition, the functional group on the surface of the negative electrode carrier, which has been a problem, can be removed. Therefore, a non-aqueous solvent secondary battery with improved charge / discharge efficiency and charge / discharge cycle life and stable battery performance can be obtained.
【００２１】[0021]
【実施例】以下、本発明を実施例及び比較例により、図
面を参照しつつ詳細に説明する。なお、本発明は実施例
によって限定されるものではない。DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings by way of examples and comparative examples. The present invention is not limited by the embodiments.
【００２２】実施例 市販の炭酸リチウムと炭酸コバルトを、ＬｉとＣｏのモ
ル比がＬｉ／Ｃｏ＝１．１０になるように秤量し、乳鉢
を用いて十分に混合した。この混合物をアルミナ製のル
ツボに入れ、電気炉により、８００℃で６時間加熱処理
を行った。得られた焼成物を冷却後、再度粉砕し、同様
に８００℃で６時間加熱処理を行った。その後、蒸留水
で十分に洗浄し、未反応のアルカリ分を洗い流した。生
成物は粉末Ｘ線法でＬｉＣｏＯ2 と確認された。この生
成物を９０重量％、導電剤としてアセチレンブラックを
７重量％及び結着剤としてエチレン−プロピレン−環状
ジエンの三元共重合体３重量％をヘキサン中で混練して
スラリー状の正極合剤を調製した。この正極合剤を厚さ
１０μm のステンレス基板上に塗布・風乾した後、加圧
して一定の厚さにし、続いて、０．２６mm厚の正極合剤
層を有する板状の正極を製造した。Example Commercially available lithium carbonate and cobalt carbonate were weighed so that the molar ratio of Li to Co became Li / Co = 1.10, and thoroughly mixed using a mortar. This mixture was placed in an alumina crucible and heat-treated at 800 ° C. for 6 hours in an electric furnace. After the obtained fired product was cooled, it was pulverized again, and similarly heated at 800 ° C. for 6 hours. Thereafter, the resultant was sufficiently washed with distilled water to wash away unreacted alkali components. The product was identified as LiCoO 2 by powder X-ray method. A 90% by weight of this product, 7% by weight of acetylene black as a conductive agent, and 3% by weight of a terpolymer of ethylene-propylene-cyclic diene as a binder are kneaded in hexane to form a slurry-like positive electrode mixture. Was prepared. This positive electrode mixture was applied on a stainless steel substrate having a thickness of 10 μm, air-dried, and then pressurized to a constant thickness. Subsequently, a plate-like positive electrode having a 0.26 mm thick positive electrode mixture layer was produced.
【００２３】一方、負極担持体である炭素質材料は、ノ
ボラック樹脂を窒素雰囲気化で、９５０℃で焼成した
後、さらに、２，０００℃に加熱して炭素化し、粉砕し
て平均粒径１０μm の粉末とすることによって得た。On the other hand, the carbonaceous material as the negative electrode carrier is obtained by calcining a novolak resin at 950 ° C. in a nitrogen atmosphere, heating it to 2,000 ° C., pulverizing it, and pulverizing it. And obtained as a powder.
【００２４】ＳｉＯ2 ／Ｌｉ2 Ｏモル比が４．５のリチ
ウムシリケートを結着剤として使用した。また、基板に
負極担持体を主成分とする合剤を塗布する際、適当な粘
度が得られるよう、増粘剤としてＣＭＣを用いた。この
ＣＭＣはエーテル化度：１、平均重合度：１，０００、
平均分子量：５０，０００であり、中和してアンモニウ
ム塩としたものである。これら、負極担持体、結着剤及
び増粘剤を９５：３：２の割合とし、負極担持体１００
に対して８０の蒸留水を加えて混練し、負極合剤スラリ
ーを作成した。この負極合剤を厚さ２０μm のニッケル
基板上に塗布・乾燥して、厚さ０．２mmの負極合剤層を
有する帯状の負極を製造した。その後、２００℃で１０
時間真空乾燥を行った。以下の電池作成は、相対湿度１
％以下のグローブボックス内で行った。Lithium silicate having a SiO 2 / Li 2 O molar ratio of 4.5 was used as a binder. In addition, when applying a mixture containing a negative electrode carrier as a main component to a substrate, CMC was used as a thickener so as to obtain an appropriate viscosity. This CMC has a degree of etherification of 1, an average degree of polymerization of 1,000,
Average molecular weight: 50,000, neutralized to ammonium salt. The negative electrode carrier, the binder, and the thickener were in a ratio of 95: 3: 2, and the negative electrode carrier 100
80 distilled water was added thereto and kneaded to prepare a negative electrode mixture slurry. This negative electrode mixture was applied on a nickel substrate having a thickness of 20 μm and dried to produce a strip-shaped negative electrode having a negative electrode mixture layer having a thickness of 0.2 mm. Thereafter, at 200 ° C. for 10
Vacuum drying was performed for hours. The following batteries were made with a relative humidity of 1
% In a glove box.
【００２５】このようにして得られた正・負極を用い
て、図１に示すような単三（ＡＡ）サイズの非水溶媒二
次電池を組み立てた。すなわち、非水溶媒二次電池１
は、底部に絶縁体２が配置され、負極端子を兼ねる有底
円筒状のステンレス容器３を有する。この容器３には、
電極群４が収納されている。この電極群４は、負極５、
セパレータ６及び正極７をこの順序で積層した帯状物
を、負極５が外側に位置するように渦巻き状に巻回した
構造になっている。前記のセパレータ６は、電解液を含
浸したポリプロピレン性多孔質フィルムから形成されて
いる。各電解液は、プロピレンカーボネートと１，２−
ジメトキシエタンとの混合溶媒（体積比率５０：５０）
に、電解質として六フッ化リン酸リチウム（ＬｉＰＦ6)
を０．５モル濃度含有する。Using the positive and negative electrodes thus obtained, an AA (AA) size non-aqueous solvent secondary battery as shown in FIG. 1 was assembled. That is, the non-aqueous solvent secondary battery 1
Has a bottomed cylindrical stainless steel container 3 in which an insulator 2 is disposed at the bottom and also serves as a negative electrode terminal. In this container 3,
The electrode group 4 is housed. The electrode group 4 includes a negative electrode 5,
A belt-like material in which the separator 6 and the positive electrode 7 are laminated in this order is wound in a spiral shape so that the negative electrode 5 is located outside. The separator 6 is formed of a polypropylene porous film impregnated with an electrolytic solution. Each electrolytic solution was composed of propylene carbonate and 1,2-
Mixed solvent with dimethoxyethane (volume ratio 50:50)
And lithium hexafluorophosphate (LiPF 6 ) as electrolyte
Is contained at 0.5 molar concentration.
【００２６】容器３内で前記の電極群４の上方には、中
心を開口した絶縁板８が配置されている。前記の容器３
の上部開口部には、絶縁封口体９が、容器３に気密にか
しめ固定されている。この絶縁板８の中央開口部には、
正極端子１０が嵌合されている。この正極端子１０は、
前記の正極７に正極リード１１を介して接続されてい
る。なお、前記の負極５は、図示しない負極リードを介
して負極端子である前記の容器３に接続されている。An insulating plate 8 having an opening at the center is arranged above the electrode group 4 in the container 3. The container 3
An insulating sealing body 9 is air-tightly fixed to the container 3 at the upper opening of the container 3. In the central opening of the insulating plate 8,
The positive electrode terminal 10 is fitted. This positive terminal 10 is
The positive electrode 7 is connected to the positive electrode 7 via a positive electrode lead 11. The negative electrode 5 is connected to the container 3 as a negative terminal via a negative lead (not shown).
【００２７】比較例１ 負極の結着剤にポリテトラフルオロエチレンを用いた以
外は実施例と同様にして、非水溶媒二次電池を組み立て
た。Comparative Example 1 A non-aqueous solvent secondary battery was assembled in the same manner as in Example except that polytetrafluoroethylene was used as a binder for the negative electrode.
【００２８】比較例２ 負極の結着剤にエチレン−プロピレン−環状ジエンの三
元共重合体を用い、増粘剤を用いず、乾燥条件を１００
℃で１０時間真空乾燥とした以外は実施例と同様にし
て、非水溶媒二次電池を組み立てた。Comparative Example 2 A terpolymer of ethylene-propylene-cyclic diene was used as a binder for the negative electrode, no thickener was used, and the drying conditions were 100
A non-aqueous solvent secondary battery was assembled in the same manner as in Example, except that vacuum drying was performed at 10 ° C. for 10 hours.
【００２９】比較例３ 負極の作成における乾燥条件が１００℃で１０時間の真
空乾燥であること以外は実施例と同様にして、非水溶媒
二次電池を組み立てた。Comparative Example 3 A non-aqueous solvent secondary battery was assembled in the same manner as in Example except that the drying conditions in the preparation of the negative electrode were vacuum drying at 100 ° C. for 10 hours.
【００３０】このようにして組み立てた実施例、比較例
１、２及び３の４種類の非水溶媒二次電池について、２
０℃の一定温度、１００mAの一定電流で４．３Ｖから
３．０Ｖまでの電圧範囲の充放電評価を行った。その結
果を図２に示す。図２のＡは本発明による実施例の電
池、Ｂは比較例１の電池、Ｃは比較例２の電池、Ｄは比
較例３の電池の放電容量維持率曲線である。With respect to the four types of non-aqueous solvent secondary batteries of Example and Comparative Examples 1, 2 and 3 assembled in this way,
Charge / discharge evaluation was performed in a voltage range from 4.3 V to 3.0 V at a constant temperature of 0 ° C. and a constant current of 100 mA. The result is shown in FIG. FIG. 2A is a discharge capacity retention rate curve of the battery of the example according to the present invention, B is a battery of Comparative Example 1, C is a battery of Comparative Example 2, and D is a battery of Comparative Example 3.
【００３１】比較例１の電池は、充放電サイクルが進む
につれて放電容量が大きく低下してきている。評価を終
了した電池を分解し負極電極の表面状態を観察すると、
比較例１の電池は、負極活物質が基板から剥離してお
り、これはリチウムと結着剤であるポリテトラフルオロ
エチレンとが反応して、結着剤が分解したためと考えら
れる。このような状態になった電極では、基板と負極担
持体粒子との電気的接触がとれなくなり、電池反応をす
る負極担持体の量が減るため、放電容量が低下する。In the battery of Comparative Example 1, the discharge capacity was greatly reduced as the charge / discharge cycle progressed. Disassembling the battery after the evaluation and observing the surface state of the negative electrode,
In the battery of Comparative Example 1, the negative electrode active material was peeled off from the substrate, which is considered to be due to the reaction between lithium and polytetrafluoroethylene as the binder, and the binder was decomposed. In the electrode in such a state, electrical contact between the substrate and the negative electrode carrier particles is lost, and the amount of the negative electrode carrier that undergoes a battery reaction is reduced, so that the discharge capacity is reduced.
【００３２】比較例２の電池は、初回放電容量が低い。
これは乾燥温度が１００℃と低いことによる。比較例１
に比べて放電容量の低下は少ないが、充放電サイクルが
進むにしたがって徐々に放電容量が低下してくる。評価
試験後、この電池を分解してみると、電極表面にかなり
のリチウムが析出していた。これは負極結着剤にエチレ
ン−プロピレン−環状ジエンの三元共重合体を用いたた
め、負極担持体表面を結着剤が覆い、負極担持体と電解
液との接触部分を少なくしてしまったため、負極容量が
少なくなり、負極がリチウム析出電位以下になって、リ
チウムの析出を起こし、放電容量が低下したものと考え
られる。The battery of Comparative Example 2 has a low initial discharge capacity.
This is because the drying temperature is as low as 100 ° C. Comparative Example 1
However, the discharge capacity gradually decreases as the charge / discharge cycle progresses. When the battery was disassembled after the evaluation test, considerable lithium was deposited on the electrode surface. This is because the terpolymer of ethylene-propylene-cyclic diene was used as the negative electrode binder, so that the surface of the negative electrode support was covered with the binder, and the contact portion between the negative electrode support and the electrolytic solution was reduced. It is considered that the negative electrode capacity decreased, the negative electrode became lower than the lithium deposition potential, lithium was precipitated, and the discharge capacity decreased.
【００３３】また、比較例３の電池は、１回目の放電容
量が極端に少ない。これは初回充電時に負極担持体で還
元されたリチウム金属が、負極担持体表面に残存してい
る官能基と反応してリチウムが次の放電時に活物質とし
て使用できなくなるためである。２回目のサイクルから
は実施例の電池と同程度の容量保持率に回復するが、さ
らにサイクルが進むにしたがって、両者の容量保持率の
差が大きくなる。これは、電極乾燥温度が、増粘剤とし
て用いたＣＭＣの分解温度以下であるため、水溶性高分
子が電極内に残り、負極の内部抵抗が増加して、電池の
重負荷放電の能力を低下させているためと考えられる。The battery of Comparative Example 3 has an extremely small first discharge capacity. This is because the lithium metal reduced by the negative electrode support at the time of the first charge reacts with the functional group remaining on the surface of the negative electrode support, and lithium cannot be used as an active material at the next discharge. After the second cycle, the capacity retention rate is restored to the same level as that of the battery of the example. However, as the cycle progresses, the difference between the two capacity retention rates increases. This is because the electrode drying temperature is equal to or lower than the decomposition temperature of the CMC used as a thickener, so that the water-soluble polymer remains in the electrode, the internal resistance of the negative electrode increases, and the capacity of the battery for heavy load discharge is increased. It is thought that it is lowering.
【００３４】これらの比較例の電池に対し、実施例の電
池は、用いられた水溶性高分子の分解温度以上に電極乾
燥温度を上げてもリチウムシリケートがその性質を維持
しているため、充放電性能には関係しない水溶性高分子
を分解除去でき、その上、従来の課題であった負極担持
体表面にある官能基も除去できるため、初回放電時に容
量が少ないということもなく、その後も高い放電容量を
維持していることがわかる。このように、本実施例の非
水溶媒二次電池は、充放電サイクルを繰り返し行っても
高い放電容量を示している。In contrast to the batteries of the comparative examples, the batteries of the examples were not fully charged because the lithium silicate maintained its properties even when the electrode drying temperature was raised to a temperature higher than the decomposition temperature of the water-soluble polymer used. Since the water-soluble polymer that is not related to the discharge performance can be decomposed and removed, and the functional group on the surface of the negative electrode carrier, which was a conventional problem, can also be removed, so that the capacity is not small at the time of the first discharge, and thereafter. It can be seen that a high discharge capacity is maintained. As described above, the non-aqueous solvent secondary battery of this example shows a high discharge capacity even after repeated charge / discharge cycles.
【図１】実施例の非水溶媒二次電池を示す一部断面図で
ある。FIG. 1 is a partial cross-sectional view showing a non-aqueous solvent secondary battery of an example.
【図２】実施例及び比較例の非水溶媒二次電池における
充放電サイクル数に対する放電容量維持率の変化を示す
特性図である。FIG. 2 is a characteristic diagram showing a change in a discharge capacity retention ratio with respect to the number of charge / discharge cycles in non-aqueous solvent secondary batteries of Examples and Comparative Examples.
１ 非水溶媒二次電池 ２ 絶縁体 ３ ステンレス容器 ４ 電極群 ５ 負極 ６ セパレータ ７ 正極 ８ 絶縁板 ９ 絶縁封口板 １０ 正極端子 １１ 正極リード Ａ 実施例の電池の放電容量維持率曲線 Ｂ 比較例１ 〃 〃 Ｃ 比較例２ 〃 〃 Ｄ 比較例３ 〃 〃 DESCRIPTION OF SYMBOLS 1 Non-aqueous solvent secondary battery 2 Insulator 3 Stainless steel container 4 Electrode group 5 Negative electrode 6 Separator 7 Positive electrode 8 Insulating plate 9 Insulating sealing plate 10 Positive electrode terminal 11 Positive electrode lead A Discharge capacity retention rate curve of battery of Example B Comparative example 1 〃 〃 C Comparative Example 2 〃 〃 D Comparative Example 3 〃
───────────────────────────────────────────────────── フロントページの続き (72)発明者 石原 洋司 東京都品川区南品川三丁目４番10号 東 芝電池株式会社内 (56)参考文献 特開 昭58−147964（ＪＰ，Ａ) 特開 昭57−90871（ＪＰ，Ａ) 特開 昭61−288374（ＪＰ，Ａ) 特開 昭61−284061（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) H01M 4/62 H01M 4/02 H01M 10/40 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yoji Ishihara 3-4-10 Minamishinagawa, Shinagawa-ku, Tokyo Toshiba Battery Corporation (56) References JP-A-58-147964 (JP, A) JP-A-58-147964 JP-A-57-90871 (JP, A) JP-A-61-288374 (JP, A) JP-A-61-284061 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) H01M 4 / 62 H01M 4/02 H01M 10/40
Claims (2)
カリ金属を担持した炭素質材料からなる負極体と、セパ
レータと、リチウム含有複合酸化物を正極活物質とする
正極体とを、この順序で一体的に積層してなる発電要素
を具備する非水溶媒二次電池において、該負極体の結着
剤としてリチウムシリケートを用いることを特徴とする
非水溶媒二次電池。1. An anode body made of a carbonaceous material carrying lithium or an alkali metal mainly composed of lithium, a separator, and a cathode body made of a lithium-containing composite oxide as a cathode active material are integrally formed in this order. A non-aqueous solvent secondary battery comprising a power generating element laminated on a non-aqueous solvent secondary battery, wherein lithium silicate is used as a binder for the negative electrode body.
Ｌｉ2Ｏ比が、モル比で３．２〜７．８である請求項１
記載の非水溶媒二次電池。2. The lithium silicate according to claim 2, wherein said lithium silicate is SiO 2 /
Li 2 O ratio, claim 1 is 3.2 to 7.8 molar ratio
The non-aqueous solvent secondary battery according to the above.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3160863A JP3016627B2 (en) | 1991-06-06 | 1991-06-06 | Non-aqueous solvent secondary battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3160863A JP3016627B2 (en) | 1991-06-06 | 1991-06-06 | Non-aqueous solvent secondary battery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04363865A JPH04363865A (en) | 1992-12-16 |
| JP3016627B2 true JP3016627B2 (en) | 2000-03-06 |
Family
ID=15724009
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|---|---|---|---|
| JP3160863A Expired - Fee Related JP3016627B2 (en) | 1991-06-06 | 1991-06-06 | Non-aqueous solvent secondary battery |
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| US5856045A (en) * | 1996-11-13 | 1999-01-05 | Mitsubshi Chemical Corporation | Lithium ion electrolytic cell and method for fabricating same |
| US6869547B2 (en) | 1996-12-09 | 2005-03-22 | Valence Technology, Inc. | Stabilized electrochemical cell active material |
| US6183718B1 (en) | 1996-12-09 | 2001-02-06 | Valence Technology, Inc. | Method of making stabilized electrochemical cell active material of lithium manganese oxide |
| US5869207A (en) * | 1996-12-09 | 1999-02-09 | Valence Technology, Inc. | Stabilized electrochemical cell |
| US6322744B1 (en) | 1999-02-17 | 2001-11-27 | Valence Technology, Inc. | Lithium manganese oxide-based active material |
| US6468695B1 (en) | 1999-08-18 | 2002-10-22 | Valence Technology Inc. | Active material having extended cycle life |
| EP2362468A1 (en) * | 2008-11-28 | 2011-08-31 | Sumitomo Chemical Company, Limited | Electrode film, electrode, method for manufacturing the electrode, and electrical storage device |
| JP6369818B2 (en) * | 2016-10-14 | 2018-08-08 | Ａｔｔａｃｃａｔｏ合同会社 | Electrode using skeleton-forming agent |
| JP6149147B1 (en) * | 2016-11-25 | 2017-06-14 | Ａｔｔａｃｃａｔｏ合同会社 | Framework forming agent and negative electrode using the same |
| CN110024188B (en) * | 2016-11-30 | 2022-10-25 | 松下知识产权经营株式会社 | Negative electrode material and nonaqueous electrolyte secondary battery |
| CN115023823A (en) * | 2020-01-31 | 2022-09-06 | 松下知识产权经营株式会社 | Negative electrode for nonaqueous electrolyte secondary battery, and method for producing negative electrode for nonaqueous electrolyte secondary battery |
-
1991
- 1991-06-06 JP JP3160863A patent/JP3016627B2/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014001799A (en) * | 2012-06-19 | 2014-01-09 | Kojima Seisakusho:Kk | Piping pulling-out jig |
| US11701764B2 (en) | 2018-05-31 | 2023-07-18 | KYOOKA Co., Ltd. | Sleeve-component extracting jig |
| KR102595133B1 (en) * | 2021-12-21 | 2023-10-27 | 주식회사 한국가스기술공사 | Shaft separtion device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04363865A (en) | 1992-12-16 |
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