JPH08241717A - Secondary battery - Google Patents
Secondary batteryInfo
- Publication number
- JPH08241717A JPH08241717A JP7085874A JP8587495A JPH08241717A JP H08241717 A JPH08241717 A JP H08241717A JP 7085874 A JP7085874 A JP 7085874A JP 8587495 A JP8587495 A JP 8587495A JP H08241717 A JPH08241717 A JP H08241717A
- Authority
- JP
- Japan
- Prior art keywords
- battery
- active material
- electrode active
- negative electrode
- lithium
- 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.)
- Pending
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)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は、非水電解液二次電池
の安全性の改善に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improving the safety of non-aqueous electrolyte secondary batteries.
【０００２】[0002]
【従来の技術】電子機器の小型化、軽量化が進められる
中、その電源として高エネルギー密度の二次電池の要望
がさらに強まっている。しかも既存の二次電池としては
これらの要望に辛うじて答えているのがニッケルカドミ
ウム二次電池であり、カドミウムにからむ環境問題等が
付きまとい、使用後の電池の回収等厄介な問題がある。
ニッケルカドミウム電池に代わる、無公害で、高性能な
二次電池の有力候補としては、非水電解液二次電池がも
っとも有望で、古くからその実用化が試みられてきた。
従来の水溶液系の電解液では金属亜鉛以上に卑な電位を
持つ物質は水を分解するため、負極活物質としては使用
できなかった。しかし非水電解液では最も卑な電位を持
つリチウム金属でも負極活物質として使用できるため、
非水電解液二次電池は素電池単位で電圧の高い電池が作
成可能となる。また正極活物質としても従来水溶液電解
液には溶解するために活物質としては使用できなかった
物質も、非水電解液には溶解しないものが多く、多くの
種類の物質が非水電解液電池の正極活物質候補となりう
る。既にこれまで主なものでも百種類を越える物質が非
水電解液二次電池用の活物質として検討された。しかし
微小容量のコイン型電池を除き、実用できる非水電解液
二次電池は出現しなかった。その理由は実用電池には電
気的特性だけでなく、その他に種々（例えば大きさや形
状、安全性、材料コスト、保存性能等）の必要欠くべか
らざる条件が要求され、何れかの特性や条件が致命的に
悪ければ実用電池とはならないからである。特に安全性
の確保は最優先されなければならない。実用可能な電池
は、いかなる公知の要素技術の組合せによって類推して
も、その完成の可否は類推不可能であり、結局、実用目
的に合致する大きさ、形で電池を作成し、実用可能か否
かの確認をする以外完成の道はない。特に実用化のため
の重要項目は安全性であり、安全性についての多くは理
論的に保証することの出来ない特性のひとつである。非
水電解液二次電池として、１９９０年以前に唯一実用化
が試みられたのは、金属リチウムを負極活物質とし、二
硫化モリブデンを正極活物質とする単３サイズの非水電
解液二次電池ただひとつであり、結局この電池は携帯電
話で使用中に発火するという事故を起こしてしまい、実
用化は断念されてしまった。ようやく最近になって、カ
ーボンへのリチウムイオンの出入りを利用するカーボン
電極を負極とする非水電解液二次電池が開発され、やっ
と非水電解液二次電池も実用化の段階に入った。この電
池は本発明者等によってリチウムイオン二次電池と名付
けて、１９９０年（雑誌Ｐｒｏｇｒｅｓｓ ｉｎ Ｂａ
ｔｔｅｒｉｅｓ ＆ Ｓｏｌａｒ Ｃｅｌｌｓ，Ｖｏ
ｉ．９．Ｐ．２０９）に初めて世の中に紹介されたもの
で、正極活物質にはリチウムイオンの離脱をともなって
電気化学的酸化還元反応が可能なリチウム含有化合物
（例えばＬｉＣｏＯ２やＬｉＭｎ２Ｏ４等）を使用し、
負極には炭素質材料を使用する。この電池は充電するこ
とによって正極活物質中に含有されるリチウムイオンが
引き抜かれて、負極の炭素材料中にリチウムイオンが進
入（インタカレート）して蓄電される。炭素材料
（Ｕ．Ｓ．Ｐａｔ．４，４２３，１２５参照）を非水電
解液電池の負極活物質とする提案やＬｉＣｏＯ２（Ｕ．
Ｓ．Ｐａｔ．４，３０２，５１８参照）あるいはＬｉＭ
ｎ２Ｏ４（Ｕ．Ｓ．Ｐａｔ．４，３１２，９３０参照）
を非水電解液電池の正極活物質とする提案は、個々には
何れも１９８０年代初めには既に提案れている公知の事
実であった。本発明者等による前記リチウムイオン二次
電池の実用化のポイントは個々の提案を合体し、実用目
的に合致する大きさ、形で電池を作成し、実用可能か否
かの確認をしたところにある。特に実用に対して充分な
安全性が確保されるかどうかが大きな確認事項であった
ことはいうまでもない。しかし正極活物質にＬｉＣｏＯ
２を使用し、負極活物質に炭素材料を使用する前記リチ
ウムイオン二次電池は、まだ既存の電池の代替に成りえ
ないいくつかの問題が残されている。ひとつは電池価格
であり、もうひとつは安全性である。正極活物質とする
ＬｉＣｏＯ２がＣｏの資源的理由からきわめて高価な材
料であり電池価格を引き上げる。ＬｉＣｏＯ２に代わる
正極材料としてスピネル型リチウムマンガン酸化物（Ｌ
ｉＭｎ２Ｏ４）が提案されているが、容量的にはややＬ
ｉＣｏＯ２より少なくなるので、まだ価格差以上に性能
重視の用途に限られたリチウムイオン二次電池の使用範
囲では歓迎されず、実用化にいたってはいない。さらに
現状のリチウムイオン二次電池はいかなる状況でも安全
と言うものではない。もし電池温度が１５０℃以上に達
すると、電池は激しく発熱して発煙したり、発火したり
する。従って、前記リチウムイオン二次電池の本発明者
らによる実用化は、内部ショートや外部短絡事故に際し
ても自己発熱により電池温度か１５０℃を越えない程度
の小型の電池（１〜１．５Ａｈ以下）に限定して可能で
あったのである。前記リチウムイオン二次電池が高温で
発火するメカニズムは、最終的には充電状態にある正極
活物質が分解して電池容器内で多量の酸素を発生し、電
池内容物が燃焼すると考えられる。正極活物質にＬｉＣ
ｏＯ２を使用した場合、充電状態の正極活物質は約半分
のリチウムが引き抜かれた状態（ＬｉＹＣｏＯ２、Ｙ≒
０．５）になっていて、分解温度以上では（１）式のよ
うに分解すると考えられる。分解温度は約２６０℃であ
ると報告されている。 Ｌｉ０．５ＣｏＯ２→０．５ＬｉＣｏＯ２＋０．５ＣｏＯ＋０．２５Ｏ２・・ ・（１） 負極活物質として炭素材料を使用しているリチウムイオ
ン二次電池では、充電によって正極よりリチウムイオン
が引き抜かれ、負極活物質の炭素の層間にリチウムイオ
ンがインタカレートする。リチウムイオンがインタカレ
ートした炭素（ＬｉＣ６）は比較的安定な化合物ではあ
るが、やはり金属リチウムに近いかなり卑な単極電位を
もつだけに、かなり活性であり、基本的には電解液とも
反応する。しかし常温では電解液との反応生成物がカー
ボン表面を被い、これが電解液との反応を抑制する働き
をするため、常温ではなんとか安全に機能する。しかし
高温では電解液との反応は激しくなり、結局１５０℃以
上では熱暴走してしまうものと考えられる。こうして電
解液とＬｉＣ６が反応して電池内温度がさらに上昇して
正極活物質の分解温度に達すれば、電池内は酸素で充満
され、電池内容物が燃焼して電池は発火するに至る。電
池内部の温度は取り出す電流が大きい場合には内部発熱
によってかなり上昇するので、現在のリチウムイオン二
次電池は大電流を取り出す用途には使用すべきではな
い。また大きいサイズのリチウムイオン二次電池はもし
内部ショートや外部短絡などの事故に際しては、ショー
ト電流は電池容量に比例して大きくなり、電池内発熱量
がおおくなり、電池内部温度が上昇するので危険であ
る。リチウムイオン二次電池をもっと安全な電池とする
ためには、まずは正極活物質としてその充電状態での分
解温度が高い材料が好ましい。正極活物質にスピネル型
リチウムマンガン酸化物（ＬｉＭｎ２Ｏ４）を使用した
場合、充電状態では正極活物質中のリチウムはほぼ全量
が引き抜かれた状態（λＭｎＯ２）になる。もちろんλ
ＭｎＯ２も分解温度以上ではやはり（２）式のように分
解すると考えられるが、分解温度は約４６０℃以上であ
ると報告されている。 λＭｎＯ２→０．５Ｍｎ２Ｏ３＋０．２５Ｏ２・・・（２） 前述の価格的特徴に加えてＬｉＭｎ２Ｏ４はＬｉＣｏＯ
２に比べその充電状態での分解温度が２００℃も高く、
安全性の高いリチウムイオン二次電池の実現に好都合な
正極材料と言える。しかし実際正極活物質にＬｉＭｎ２
Ｏ４を使用し、負極に炭素材料を使用したリチウムイオ
ン二次電池でも、電池を押し潰したりした場合には発火
してしまう。このことは電池がいったん電解液とＬｉＣ
６が反応するに十分な温度にまで上昇すると、熱暴走を
はじめ、電池内温度がさらに上昇して（２）式の分解温
度にまで達してしまうことになると考えられる。リチウ
ムイオン二次電池を安全な電池とするためには、負極活
物質と電解液の反応を阻止しなければ、たとえ分解温度
の高いリチウムマンガン酸化物を正極活物質に採用して
も、その効果が実際上現れにくい。従って既存の二次電
池の代替となりうる安価で、安全なリチウムイオン二次
電池の実現には、 １．正極材料としてリチウムマンガン酸化物等の安価な
材料をを使用し、 ２．負極材料にはその充電状態での電極電位がＬｉＣ６
よりももっと貴な電位である物質を使用することによっ
て、負極活物質と電解液の反応を阻止することが必要で
ある。 当然貴な負極電位は電池電圧を低くするため、安全性は
よくなっても、エネルギー密度は低下する。しかし、重
要なことは安全性とエネルギー密度をよくバランスする
ことであり、その達成にはリチウムマンガン酸化物と組
み合わせるべき新しい負極材料の発掘が重要な鍵であ
る。米国特許４，９８３、４７６には正極活物質として
ＬｉＣｏＯ２、ＬｉＦｅＯ２、ＬｉＭｎＯ２、ＬｉＣｒ
Ｏ２等のリチウム含有化合物を使用し、負極にはＴｉＳ
２、ＶＳ２、ＣｄＳ２、ＮｂＳ２、ＦｅＳ２等の遷移金
属の硫化物を使用する二次電池が提案さているが、電池
電圧は１〜１．２Ｖ程度となってしまい、エネルギー密
度は１００ｗｈ／ｌ以下となってしまう。これでは既存
の二次電池以下の値であり、エネルギー密度の点で満足
できるものではない。既存のニッケルカドミウム二次電
池のエネルギー密度は１００〜１５０ｗｈ／ｌであり、
リチウムイオン二次電池に対して安全性の高さを強く要
求すれども、そのエネルギー密度は１５０ｗｈ／ｌ以
上、好ましくは１８０ｗｈ／ｌを達成しなければ、既存
の電池の代替とはなりえない。2. Description of the Related Art As electronic devices are becoming smaller and lighter, there is a growing demand for high energy density secondary batteries as their power sources. Moreover, the nickel-cadmium secondary battery barely responds to these demands as an existing secondary battery, and is accompanied by an environmental problem related to cadmium, and there are troublesome problems such as recovery of the battery after use.
Non-aqueous electrolyte secondary batteries are the most promising candidates for non-polluting, high-performance secondary batteries to replace nickel-cadmium batteries, and their practical application has been tried for a long time.
In the conventional aqueous electrolyte solution, a substance having a base potential lower than that of metallic zinc decomposes water and thus cannot be used as a negative electrode active material. However, in the non-aqueous electrolyte, even lithium metal, which has the most base potential, can be used as the negative electrode active material,
The non-aqueous electrolyte secondary battery can be made to have a high voltage in unit cell unit. In addition, many positive electrode active materials that could not be used as active materials because they are conventionally soluble in aqueous electrolytes are not soluble in non-aqueous electrolytes, and many types of substances are non-aqueous electrolyte batteries. Can be a positive electrode active material candidate. So far, more than 100 kinds of major substances have been studied as active materials for non-aqueous electrolyte secondary batteries. However, a non-aqueous electrolyte secondary battery that can be used practically did not appear except for a coin-type battery having a small capacity. The reason is that practical batteries are required to have not only electrical characteristics but also various other necessary and indispensable conditions (for example, size and shape, safety, material cost, storage performance, etc.). This is because if it is fatally bad, it will not be a practical battery. In particular, ensuring safety must be a top priority. It is impossible to infer the feasibility of a practical battery by analogy with any known combination of elemental technologies.In the end, it is possible to make a battery in a size and shape that matches the practical purpose and to put it into practical use. There is no way to complete it, except to confirm it. In particular, safety is an important item for practical use, and many of safety are one of the characteristics that cannot be theoretically guaranteed. The only non-aqueous electrolyte secondary battery that was attempted to be put into practical use before 1990 was a non-aqueous electrolyte secondary battery of AA size that used metallic lithium as a negative electrode active material and molybdenum disulfide as a positive electrode active material. Since there is only one battery, this battery eventually ignited while being used in a mobile phone, and its practical application was abandoned. Only recently, a non-aqueous electrolyte secondary battery having a carbon electrode as a negative electrode, which utilizes the inflow and outflow of lithium ions into carbon, has been developed, and finally the non-aqueous electrolyte secondary battery has also entered the stage of practical application. This battery was named a lithium-ion secondary battery by the present inventors and was named in 1990 (Progress in Ba magazine).
tterries & Solar Cells, Vo
i. 9. P. 209), the lithium-containing compound (for example, LiCoO 2 or LiMn 2 O 4 etc.) capable of electrochemical redox reaction with desorption of lithium ion was used for the positive electrode active material. ,
A carbonaceous material is used for the negative electrode. When this battery is charged, the lithium ions contained in the positive electrode active material are extracted, and the lithium ions enter (intercalate) into the carbon material of the negative electrode to store electricity. Carbon material
(See US Pat. 4,423,125) as a negative electrode active material of a non-aqueous electrolyte battery or LiCoO 2 (U.S. Pat.
S. Pat. 4, 302, 518) or LiM
n 2 O 4 (see US Pat. 4,312,930)
Each of the proposals to use as a positive electrode active material for a non-aqueous electrolyte battery was a known fact already proposed in the early 1980s. The point of practical application of the lithium ion secondary battery by the present inventors is to combine the individual proposals, create a battery with a size and shape that match the practical purpose, and confirm whether it is practical or not. is there. Needless to say, a big confirmation item was whether or not sufficient safety was secured for practical use. However, as the positive electrode active material, LiCoO
The lithium-ion secondary battery using No. 2 and a carbon material as the negative electrode active material still has some problems that cannot replace the existing battery. One is battery price and the other is safety. LiCoO 2 used as the positive electrode active material is an extremely expensive material because of the resource of Co, and raises the battery price. Spinel-type lithium manganese oxide as a positive electrode material in place of LiCoO 2 (L
iMn 2 O 4 ) has been proposed, but it is slightly L in terms of capacity.
Since it is less than iCoO 2, it is not welcomed in the range of use of the lithium-ion secondary battery which is limited to performance-oriented applications more than the price difference, and has not been put into practical use. Furthermore, current lithium-ion secondary batteries are not safe under any circumstances. If the battery temperature reaches 150 ° C or higher, the battery heats up violently and smokes or ignites. Therefore, the practical use of the lithium-ion secondary battery by the present inventors is that the battery temperature does not exceed 150 ° C. due to self-heating even in the event of an internal short circuit or an external short circuit (1 to 1.5 Ah or less). It was possible to limit to. The mechanism by which the lithium ion secondary battery ignites at a high temperature is considered to be that the positive electrode active material in a charged state is finally decomposed to generate a large amount of oxygen in the battery container and the battery contents are burned. LiC as the positive electrode active material
When oO 2 is used, the positive electrode active material in a charged state is in a state where about half of lithium is extracted (Li Y CoO 2 , Y≈
It is 0.5), and it is considered that the decomposition occurs at the decomposition temperature or higher as shown in the equation (1). The decomposition temperature is reported to be about 260 ° C. Li 0.5 CoO 2 → 0.5LiCoO 2 + 0.5CoO + 0.25O 2 ··· (1) In a lithium ion secondary battery using a carbon material as a negative electrode active material, lithium ions are extracted from the positive electrode by charging. Lithium ions intercalate between the carbon layers of the negative electrode active material. Carbon (LiC 6 ) in which lithium ions are intercalated is a relatively stable compound, but it is also quite active because it has a fairly base monopolar potential close to that of metallic lithium, and it is basically active as an electrolyte. react. However, at room temperature, the reaction product with the electrolytic solution covers the carbon surface, and this acts to suppress the reaction with the electrolytic solution, so that at room temperature it somehow functions safely. However, it is considered that the reaction with the electrolytic solution becomes vigorous at high temperature, and eventually thermal runaway occurs at 150 ° C or higher. When the electrolytic solution and LiC 6 react in this way and the temperature inside the battery further rises to the decomposition temperature of the positive electrode active material, the inside of the battery is filled with oxygen, the contents of the battery burn, and the battery ignites. Since the internal temperature of the battery rises considerably due to internal heat generation when the current to be taken out is large, the current lithium ion secondary battery should not be used for the purpose of taking out a large current. Also, in the case of a large-sized lithium-ion secondary battery, if an accident such as an internal short circuit or an external short circuit occurs, the short-circuit current will increase in proportion to the battery capacity, the amount of heat generated in the battery will decrease, and the internal temperature of the battery will rise Is. In order to make the lithium ion secondary battery a safer battery, first, a material having a high decomposition temperature in its charged state is preferable as the positive electrode active material. When spinel type lithium manganese oxide (LiMn 2 O 4 ) is used as the positive electrode active material, almost all the lithium in the positive electrode active material is extracted (λMnO 2 ) in the charged state. Of course λ
It is considered that MnO 2 also decomposes as shown in the formula (2) above the decomposition temperature, but the decomposition temperature is reported to be about 460 ° C. or higher. λMnO 2 → 0.5Mn 2 O 3 + 0.25O 2 (2) In addition to the above price characteristics, LiMn 2 O 4 is LiCoO 2.
The decomposition temperature in the charged state is as high as 200 ℃ compared to 2 ,
It can be said that the positive electrode material is convenient for realizing a highly safe lithium-ion secondary battery. However, as a positive electrode active material, LiMn 2
Even a lithium ion secondary battery using O 4 and using a carbon material for the negative electrode will ignite when the battery is crushed. This means that once the battery is in electrolyte and LiC
It is considered that when the temperature rises to a temperature sufficient for 6 to react, thermal runaway begins and the temperature inside the battery further rises to reach the decomposition temperature of equation (2). In order to make a lithium-ion secondary battery a safe battery, if the reaction of the negative electrode active material and the electrolytic solution is not blocked, even if lithium manganese oxide with a high decomposition temperature is adopted as the positive electrode active material, Is hard to appear in practice. Therefore, in order to realize an inexpensive and safe lithium-ion secondary battery that can replace the existing secondary battery, 1. 1. An inexpensive material such as lithium manganese oxide is used as the positive electrode material, The negative electrode material has an electrode potential in the charged state of LiC 6
It is necessary to prevent the reaction between the negative electrode active material and the electrolytic solution by using a substance having a more noble potential than that. Naturally, the noble negative electrode potential lowers the battery voltage, so that the energy density is lowered although the safety is improved. However, what is important is a good balance between safety and energy density, and the discovery of new negative electrode materials that should be combined with lithium manganese oxide is an important key for achieving this. LiCoO 2 as the positive electrode active material in U.S. Patent 4,983,476, LiFeO 2, LiMnO 2, LiCr
A lithium-containing compound such as O 2 is used, and TiS is used for the negative electrode.
2, VS 2, CdS 2, NbS 2, FeS although secondary battery using a sulfide of a transition metal such as 2 have been proposed, the battery voltage becomes about 1～1.2V, energy density 100wh / L or less. This is less than the value of the existing secondary battery, and is not satisfactory in terms of energy density. The energy density of the existing nickel-cadmium secondary battery is 100 to 150 wh / l,
Although the lithium ion secondary battery is strongly required to have high safety, it cannot be a substitute for the existing battery unless the energy density thereof reaches 150 wh / l or more, preferably 180 wh / l.
【０００３】[0003]
【発明が解決しようとする課題】本発明は既存の電池以
上のエネルギー密度を確保して、安全性が高く、且つ安
価な非水電解液二次電池を完成しようとするものであ
る。DISCLOSURE OF THE INVENTION The present invention is intended to complete a non-aqueous electrolyte secondary battery which secures an energy density higher than that of existing batteries and is highly safe and inexpensive.
【０００４】[0004]
【課題を解決するための手段】課題解決の手段は、正極
の活物質材料にスピネル型リチウムマンガン酸化物を使
用し、一般式ＬｉＡ１−ＸＢＸＯ２（但し、ＡはＮｉ、
Ｃｏ、Ｆｅの何れかであり、ＢはＡと置換された３価の
イオンであり、０≦Ｘ≦０．５）で示されるリチウム含
有遷移金属複合酸化物を負極活物質として使用する。As a means for solving the problems, spinel type lithium manganese oxide is used for the active material of the positive electrode, and the general formula LiA 1-X B X O 2 (where A is Ni,
Either Co or Fe, B is a trivalent ion substituted with A, and a lithium-containing transition metal composite oxide represented by 0 ≦ X ≦ 0.5) is used as a negative electrode active material.
【０００５】[0005]
【作用】電池のエネルギー密度（ｗｈ／ｌ）は電流容量
密度（Ａｈ／ｌ）と電池電圧（ｖ）の積で与えられる。
正極にスピネル型リチウムマンガン酸化物を使用するリ
チウムイオン二次電池では、７５〜８５Ａｈ／ｌ程度の
電流容量密度が得られる。従って１８０ｗｈ／ｌのエネ
ルギー密度を持つリチウムイオン二次電池は、平均放電
電圧２．４Ｖ以上で作動する必要がある。また安全性を
向上すると言う点からは電池電圧は低いほうが好ましい
わけであるから、本発明者は電池電圧を２．４〜３．５
Ｖの範囲に目標を定め、種々の化合物について負極材料
としての可能性を鋭意検討した結果、層状構造をもつ一
般式ＬｉＡ１−ＸＢＸＯ２（但し、ＡはＮｉ、Ｃｏ、Ｆ
ｅの何れかであり、ＢはＡと置換された３価のイオンで
あり、０≦Ｘ≦０．５）で示されるリチウム含有遷移金
属複合酸化物が目的に合致する良好な負極材料となりう
ることを見いだし本発明に至った。層状構造をもつ一般
式ＬｉＡ１−ＸＢＸＯ２（但し、ＡはＮｉ、Ｃｏ、Ｆｅ
の何れかであり、ＢはＡと置換された３価のイオンであ
り、０≦Ｘ≦０．５）で示されるリチウム含有遷移金属
複合酸化物は、元来前述のリチウムイオン二次電池の正
極材料として近年盛んに研究されている材料であるが、
これを負極活物質として使用すると正極活物質としての
電極反応とはまったく異なる電気化学的反応がおこる。
負極活物質に層状構造の前記リチウム含有遷移金属複
合酸化物を使用し、正極活物質にスピネル型リチウムマ
ンガン酸化物（ＬｉＭｎ２Ｏ４）を使用したリチウムイ
オン二次電池は充電後の開路電圧は約２．７〜３．０Ｖ
となり、平均放電電圧は２．４Ｖ以上で作動できる。層
状構造をもつ一般式ＬｉＡ１−ＸＢＸＯ２で示される化
合物の負極活物質としての電気化学的酸化還元反応の反
応機構は定かではないが、例えばＬｉＮｉＯ２の場合、
次の（３）式で充放電が進行するものと考えられる。 一般式ＬｉＡ１−ＸＢＸＯ２で示される化合物が、負極
における充電状態で示す電極電位は、リチウムイオンが
ドープされた状態のカーボン材料の電極電位に比べる
と、相当（少なくとも１．０Ｖ以上）貴な電位であるた
め、電解液と反応することがなく、悪条件においても電
池自身の発熱によって電池内温度が正極活物質（λＭｎ
Ｏ２）の分解温度（≒４６０℃）に達することが無いの
で、電池が発火するような好ましからざる事態を招くこ
とがなくなる。層状構造をもつ一般式ＬｉＡ１−ＸＢＸ
Ｏ２で示される化合物は基本的にはＬｉＮｉＯ２、Ｌｉ
ＣｏＯ２、ＬｉＦｅＯ２の３つであるが、Ｎｉ３＋、Ｃ
ｏ３＋、Ｆｅ３＋（つまり一般式中のＡ３＋）を他の３
価のイオン（Ｂ３＋）で置換した形の数多くの化合物が
存在する。例えば、ＬｉＮ１−ＹＣｏＹＯ２（Ｏ＜Ｙ＜
１）、ＬｉＮｉ０．８Ｍｎ０．２Ｏ２、ＬｉＮｉ３／４
Ａｌ１／４Ｏ２等がその例であるが、これらも前記３つ
の基本的化合物と同様に負極活物質として本発明を実施
可能である。The energy density (wh / l) of the battery is given by the product of the current capacity density (Ah / l) and the battery voltage (v).
A lithium ion secondary battery using a spinel type lithium manganese oxide for the positive electrode can obtain a current capacity density of about 75 to 85 Ah / l. Therefore, a lithium ion secondary battery having an energy density of 180 wh / l needs to operate at an average discharge voltage of 2.4 V or higher. Further, from the viewpoint of improving safety, it is preferable that the battery voltage is low, so the present inventor set the battery voltage to 2.4 to 3.5.
As a result of intensive studies on the potential of various compounds as a negative electrode material by setting a target in the range of V, a general formula LiA 1-X B X O 2 (where A is Ni, Co, F
e, B is a trivalent ion substituted with A, and the lithium-containing transition metal composite oxide represented by 0 ≦ X ≦ 0.5) can be a good negative electrode material that meets the purpose. The present invention was discovered and the present invention was reached. General formula LiA 1-X B X O 2 (where A is Ni, Co, Fe) having a layered structure.
B is a trivalent ion substituted with A, and the lithium-containing transition metal composite oxide represented by 0 ≦ X ≦ 0.5 is originally a lithium-ion secondary battery Although it is a material that has been actively researched as a positive electrode material in recent years,
When this is used as the negative electrode active material, an electrochemical reaction which is completely different from the electrode reaction as the positive electrode active material occurs.
A lithium ion secondary battery using the lithium-containing transition metal composite oxide having a layered structure as the negative electrode active material and spinel type lithium manganese oxide (LiMn 2 O 4 ) as the positive electrode active material has an open circuit voltage after charging. About 2.7-3.0V
Therefore, the average discharge voltage can be operated at 2.4 V or more. The reaction mechanism of the electrochemical redox reaction of the compound represented by the general formula LiA 1-X B X O 2 having a layered structure as a negative electrode active material is not clear, but in the case of LiNiO 2 , for example,
It is considered that charging / discharging proceeds according to the following equation (3). The electrode potential of the compound represented by the general formula LiA 1-X B X O 2 in the charged state at the negative electrode is comparable (at least 1.0 V or more) to the electrode potential of the carbon material in the state where lithium ions are doped. ) Since it has a noble potential, it does not react with the electrolytic solution, and even under adverse conditions, the internal temperature of the battery increases due to the heat generated by the battery itself (λMn
Since it does not reach the decomposition temperature of O 2 (≈460 ° C.), the undesirable situation such as ignition of the battery will not occur. General formula LiA 1-X B X having a layered structure
The compound represented by O 2 is basically LiNiO 2 , Li
CoO 2 and LiFeO 2 , which are three, Ni 3+ , C
o 3+ , Fe 3+ (that is, A 3+ in the general formula) is replaced by another 3
There are numerous compounds in the valence ion (B 3+ ) substituted form. For example, LiN 1-Y Co Y O 2 (O <Y <
1), LiNi 0.8 Mn 0.2 O 2 , LiNi 3/4
Although Al 1/4 O 2 and the like are examples thereof, the present invention can also be carried out as a negative electrode active material similarly to the above three basic compounds.
【０００６】[0006]
【実施例】以下、本発明によるリチウムイオン二次電池
の実施例について、図面を参照しながら説明する。EXAMPLES Examples of the lithium ion secondary battery according to the present invention will be described below with reference to the drawings.
【０００７】実施例１ 負極活物質してリチウムコバルト複合酸化物（ＬｉＣｏ
Ｏ２）を使用した実施例を説明する。まず負極活物質と
するリチウムコバルト複合酸化物（ＬｉＣｏＯ２）は次
のようにして用意した。市販の炭酸リチウム（Ｌｉ２Ｃ
Ｏ３）と炭酸コバルト（ＣｏＣＯ３）をＬｉとＣｏの原
子比が１．０３：１の組成比になるように混合し、空気
中で９００℃約１０時間焼成してＬｉＣｏＯ２を得る。
焼成後のＬｉＣｏＯ２は非常に固い塊として得られるの
で、これを紛砕機にかけて平均粒径１０ミクロンの粉末
状とする。Example 1 A lithium cobalt composite oxide (LiCo) was used as a negative electrode active material.
An example using O 2 ) will be described. First, a lithium cobalt composite oxide (LiCoO 2 ) used as a negative electrode active material was prepared as follows. Commercially available lithium carbonate (Li 2 C
O 3 ) and cobalt carbonate (CoCO 3 ) are mixed so that the atomic ratio of Li and Co is 1.03: 1, and the mixture is fired in air at 900 ° C. for about 10 hours to obtain LiCoO 2 .
Since LiCoO 2 after firing is obtained as a very hard mass, it is ground into a powder with an average particle size of 10 microns.
【０００８】この粉末状ＬｉＣｏＯ２を９１重量部、導
電剤としてグラファイトを６重量部、結合剤としてポリ
フッ化ビニリデン３重量部を溶剤であるＮ−メチルー２
−ピロリドンと湿式混合してスラリー（ペースト状）に
する。次に、このスラリーを正極集電体となる厚さ０．
０２ｍｍのアルミニウム箔の両面に均一に塗布し、乾燥
後ローラープレス機で加圧成型してシート状の電極とし
た。このシート状電極からは電極幅を５４ｍｍに調整し
て帯状の負極（１１）を作り、真空乾燥器中、１００℃
で１２時間乾燥した。91 parts by weight of this powdery LiCoO 2 , 6 parts by weight of graphite as a conductive agent, and 3 parts by weight of polyvinylidene fluoride as a binder were used as a solvent, N-methyl-2.
Wet mix with pyrrolidone to form a slurry (paste). Next, this slurry was made to have a thickness of 0.
It was evenly applied to both sides of a 02 mm aluminum foil, dried, and then pressure-molded with a roller press to obtain a sheet-shaped electrode. From this sheet-shaped electrode, the electrode width was adjusted to 54 mm to form a strip-shaped negative electrode (11), which was then dried in a vacuum dryer at 100 ° C.
And dried for 12 hours.
【０００９】次に正極活物質とするスピネル系リチウム
マンガン酸化物を合成する。二酸化マンガン（Ｍｎ
Ｏ２）と炭酸リチウム（Ｌｉ２ＣＯ３）を１：０．２７
のモル比でよく混合し、これをを空気中８５０℃で１２
時間焼成し、室温まで温度が下がった時点で、これを平
均粒径２５ミクロンの紛末として調整し、正極活物質と
するリチウムマンガン酸化物（ＬｉＭｎ２Ｏ４）を用意
した。但しここで合成したリチウムマンガン酸化物はＸ
線回折ではスピネル型ＬｉＭｎ２Ｏ４の回折パターンと
よく一致するものであるが、マンガンの価数分析から判
断して、より正確にはマンガンの一部がリチウムで置換
されたＬｉ１．０５Ｍｎ１．９５Ｏ４と考えられる。Next, a spinel type lithium manganese oxide as a positive electrode active material is synthesized. Manganese dioxide (Mn
O 2) and lithium carbonate (Li 2 CO 3) 1: 0.27
Well mixed at a molar ratio of 12
It was calcined for a period of time, and when the temperature dropped to room temperature, it was adjusted as powder having an average particle size of 25 microns to prepare lithium manganese oxide (LiMn 2 O 4 ) as a positive electrode active material. However, the lithium manganese oxide synthesized here is X
In the line diffraction, it agrees well with the diffraction pattern of spinel type LiMn 2 O 4 , but more accurately, judging from the valence analysis of manganese, Li 1.05 Mn in which a part of manganese is replaced with lithium is more accurate. It is considered to be 1.95 O 4 .
【００１０】用意したリチウムマンガン酸化物の９０重
量部をカーボンブラックの３重量部、グラファイト４重
量部および結合剤としてポリフッ化ビニリデン４重量部
とともに溶剤であるＮ−メチル−２−ピロリドンと湿式
混合してスラリー（ペースト状）にする。このスラリー
を正極集電体とする厚さ０．０２ｍｍのアルミニウム箔
の両面に均一に塗布し、乾燥後ローラープレス機で加圧
成型してシート状の電極とした。このシート状電極も電
極幅を５４ｍｍに調整して帯状の正極（２）を作り、真
空乾燥器中、１００℃で１２時間乾燥した。90 parts by weight of the prepared lithium manganese oxide was wet-mixed with 3 parts by weight of carbon black, 4 parts by weight of graphite and 4 parts by weight of polyvinylidene fluoride as a binder together with N-methyl-2-pyrrolidone as a solvent. To make a slurry (paste). This slurry was uniformly applied to both sides of a 0.02 mm-thick aluminum foil serving as a positive electrode current collector, dried, and pressure-molded with a roller press machine to obtain a sheet-shaped electrode. This sheet-shaped electrode was also adjusted to have an electrode width of 54 mm to form a strip-shaped positive electrode (2) and dried in a vacuum dryer at 100 ° C. for 12 hours.
【００１１】電池（Ａ）の作成 帯状の負極（１）と正極（２）はその間に幅５８ｍｍの
帯状の多孔質ポリプロピレン製セパレータ（３）を挟ん
でロール状に巻き上げて、図２に示すような巻回体とし
て、外径で１７．１ｍｍ、高さ５８ｍｍの電池素子を作
成した。次にアルミニウム製の電池缶（４）の底部に絶
縁シート（１４）を設置し、上記電池素子を収納する。
電池素子より取り出した負極リード（５）を上記電池缶
の底に溶接し、電池缶の中に電解液として１モル／リッ
トルのＬｉＰＦ６を溶解したエチレンカーボネイト（Ｅ
Ｃ）とジエチルカーボネート（ＤＥＣ）の混合溶液を注
入する。その後電池素子の上部にも絶縁シート（１４）
を設置し、ガスケット（６）を嵌め、防爆弁（８）を図
３に示すように電池内部に設置する。電池素子より取り
出した正極リード（７）はこの防爆弁に電解液を注入す
る前に溶接しておく。防爆弁の上には正極外部端子とな
る閉塞蓋体（９）を重ね、電池缶の縁をかしめて、図３
に示す電池構造で、外径１８．１ｍｍ、高さ６５ｍｍの
電池（Ｃ）を作成した。Preparation of Battery (A) A strip-shaped negative electrode (1) and a positive electrode (2) were wound up in a roll with a strip-shaped porous polypropylene separator (3) having a width of 58 mm sandwiched therebetween, as shown in FIG. As a wound body, a battery element having an outer diameter of 17.1 mm and a height of 58 mm was prepared. Next, the insulating sheet (14) is placed on the bottom of the aluminum battery can (4) to house the battery element.
The negative electrode lead (5) taken out from the battery element was welded to the bottom of the battery can, and 1 mol / l of LiPF 6 was dissolved as an electrolytic solution in the battery can to obtain ethylene carbonate (E).
A mixed solution of C) and diethyl carbonate (DEC) is injected. After that, an insulating sheet (14) is also provided on the battery element.
, The gasket (6) is fitted, and the explosion-proof valve (8) is installed inside the battery as shown in FIG. The positive electrode lead (7) taken out from the battery element is welded before injecting the electrolytic solution into this explosion-proof valve. On the explosion-proof valve, a closing lid body (9) serving as a positive electrode external terminal is overlaid, and the rim of the battery can is caulked.
A battery (C) having an outer diameter of 18.1 mm and a height of 65 mm was prepared with the battery structure shown in FIG.
【００１２】実施例２ 負極活物質してリチウムニッケル複合酸化物（ＬｉＮｉ
Ｏ２）を使用した実施例を説明する。まず負極活物質と
するリチウムニッケル複合酸化物（ＬｉＮｉＯ２）は次
のようにして用意される。水酸化リチウム〔ＬｉＯＨ・
Ｈ２Ｏ〕と水酸化ニッケル〔Ｎｉ（ＯＨ）２〕をＬｉと
Ｎｉの原子比が１：１の組成比になるように混合し、酸
素雰囲気下で７８０℃約２０時間焼成してＬｉＮｉＯ２
を得る。焼成後に粉砕機にかけて平均粒径１０ミクロン
の紛末状とする。Example 2 As a negative electrode active material, a lithium nickel composite oxide (LiNi
An example using O 2 ) will be described. First, a lithium nickel composite oxide (LiNiO 2 ) used as a negative electrode active material is prepared as follows. Lithium hydroxide [LiOH
H 2 O] and nickel hydroxide [Ni (OH) 2 ] are mixed so that the atomic ratio of Li and Ni is 1: 1, and the mixture is baked in an oxygen atmosphere at 780 ° C. for about 20 hours to obtain LiNiO 2
Get. After firing, it is pulverized into a powder with an average particle size of 10 microns.
【００１３】この粉末状のＬｉＮｉＯ２を９１重量部、
導電剤としてグラファイトを６重量部、結合剤としてポ
リフッ化ビニリデン３重量部を溶剤であるＮ−メチル−
２−ピロリドンと湿式混合してスラリー（ペースト状）
にする。次にこのスラリーを厚さ０．０２ｍｍのアルミ
ニウム箔の両面に均一に塗布し、乾燥後ローラープレス
機で加圧成型してシート状の電極とした。このシート状
電極から電極幅を５４ｍｍに調整して帯状の負極（１
ｂ）を作り、真空乾燥器中１００℃で１２時間乾燥し
た。91 parts by weight of this powdery LiNiO 2 ,
6 parts by weight of graphite as a conductive agent and 3 parts by weight of polyvinylidene fluoride as a binder are N-methyl-
Wet-mix with 2-pyrrolidone to form slurry (paste)
To Next, this slurry was uniformly applied on both sides of an aluminum foil having a thickness of 0.02 mm, dried and pressure-molded by a roller press machine to obtain a sheet-shaped electrode. From this sheet electrode, the electrode width was adjusted to 54 mm and the strip-shaped negative electrode (1
b) was prepared and dried in a vacuum dryer at 100 ° C. for 12 hours.
【００１４】正極は実施例１で作成した、電極幅を５４
ｍｍに調整した帯状の正極（２）をここでも使用する。
帯状の負極（１ｂ）と正極（２）はその間に幅５８ｍｍ
の帯状の多孔質ポリプロピレン製セパレータ（３）を挟
んでロール状に巻き上げて、外径で１７．１ｍｍ、高さ
５８ｍｍの電池素子を作成した。あとは実施例１と同じ
にして、図３に示す電池構造で、外径１８．１ｍｍ、高
さ６５ｍｍの電池（Ｂ）を作成した。The positive electrode was prepared in Example 1 and had an electrode width of 54.
The strip-shaped positive electrode (2) adjusted to mm is also used here.
The width of the strip negative electrode (1b) and the positive electrode (2) is 58 mm.
The strip-shaped porous polypropylene separator (3) was sandwiched and rolled up to form a battery element having an outer diameter of 17.1 mm and a height of 58 mm. Thereafter, the same procedure as in Example 1 was carried out to prepare a battery (B) having an outer diameter of 18.1 mm and a height of 65 mm with the battery structure shown in FIG.
【００１５】実施例３ リチウムニッケルマンガン複合酸化物（ＬｉＮｉ０．９
Ｍｎ０．１Ｏ２）を負極活物質とする実施例を説明す
る。まず負極活物質とするリチウムニッケルマンガン複
合酸化物は次のようにして用意される。ＬｉＯＨ・Ｈ２
ＯとＮｉ（ＯＨ）２とγ−ＭｎＯＯＨをＬｉとＮｉとＭ
ｎの原子比が１：０．９：０．１の組成比になるように
混合し、酸素雰囲気下で８００℃約２０時間焼成してＬ
ｉＮｉ０．９Ｍｎ０．１Ｏ２を得る。焼成後に紛砕機に
かけて平均粒径が約１０ミクロンの紛末状とする。Example 3 Lithium nickel manganese composite oxide (LiNi 0.9
An example in which Mn 0.1 O 2 ) is used as the negative electrode active material will be described. First, a lithium nickel manganese composite oxide as a negative electrode active material is prepared as follows. LiOH / H 2
O, Ni (OH) 2 and γ-MnOOH are Li, Ni and M
Mix so that the atomic ratio of n is 1: 0.9: 0.1, and burn in an oxygen atmosphere at 800 ° C. for about 20 hours to obtain L
iNi 0.9 Mn 0.1 O 2 is obtained. After firing, the powder is pulverized into a powder having an average particle size of about 10 microns.
【００１６】この粉末状のＬｉＮｉ０．９Ｍｎ０．１Ｏ
２を９０重量部、導電財としてグラファイトを６重量
部、結合剤としてポリフッ化ビニリデン４重量部を溶剤
であるＮ−メチル−２−ピロリドンと湿式混合してスラ
リー（ペースト状）にする。このスラリーを厚さ０．０
２ｍｍのアルミニウム箔の両面に均一に塗布し、乾燥後
ローラープレス機で加圧成型してシート状の電極とし
た。このシート状電極から電極幅を５４ｍｍに調整して
帯状の負極（１ｃ）を作り、真空乾燥器中、１００℃で
１２時間乾燥した。This powdery LiNi 0.9 Mn 0.1 O
90 parts by weight of 2 and 6 parts by weight of graphite as a conductive material and 4 parts by weight of polyvinylidene fluoride as a binder are wet-mixed with N-methyl-2-pyrrolidone as a solvent to form a slurry (paste form). This slurry has a thickness of 0.0
A 2 mm aluminum foil was evenly applied on both sides, dried, and pressure-molded with a roller press machine to obtain a sheet-shaped electrode. An electrode width was adjusted to 54 mm from this sheet-shaped electrode to prepare a strip-shaped negative electrode (1c), which was dried in a vacuum dryer at 100 ° C. for 12 hours.
【００１７】正極は実施例１で作成した、電極幅を５４
ｍｍに調整した帯状の正極（２）をここでも使用する。
帯状の負極（１Ｃ）と正極（２）はその間に幅５８ｍｍ
の帯状の多孔質ポリプロピレン製セパレータ（３）を挟
んでロール状に巻き上げて、外径で１７．１ｍｍ、高さ
５８ｍｍの電池素子を作成した。後は実施例１と同じに
して、図３に示す電池構造で、外径１８．１ｍｍ、高さ
６５ｍｍの電池（Ｃ）を作成した。The positive electrode was produced in Example 1 and had an electrode width of 54.
The strip-shaped positive electrode (2) adjusted to mm is also used here.
The width of the strip negative electrode (1C) and the positive electrode (2) is 58 mm between them.
The strip-shaped porous polypropylene separator (3) was sandwiched and rolled up to form a battery element having an outer diameter of 17.1 mm and a height of 58 mm. Thereafter, the same procedure as in Example 1 was carried out to produce a battery (C) having an outer diameter of 18.1 mm and a height of 65 mm with the battery structure shown in FIG.
【００１８】比較例１ 本発明による電池と比較するため、負極活物質してグラ
ファイトを使用した従来型のリチウムイオン二次電池を
試作する。まず負極活物質とするグラファイト（ＫＳ１
５、ロンザ社製）の８６重量部にアセチレンブラック４
重量部と結着剤としてポリフッ化ビニリデン（ＰＶＤ
Ｆ）１０重量部を加え、溶剤であるＮ−メチル−２−ピ
ロリドンと湿式混合してスラリー（ペースト状）にし
た。このスラリーを集電体となる厚さ０．０１ｍｍの銅
箔の両面に均一に塗布し、乾燥後ローラープレス機で加
圧成型してシート状電極とし、このシート状電極から電
極幅を５４ｍｍに調整して帯状の負極（１ｄ）を作成
し、真空乾燥器中、１００℃で１２時間乾燥した。Comparative Example 1 In order to compare with the battery according to the present invention, a conventional lithium ion secondary battery using graphite as a negative electrode active material is manufactured as a prototype. First, graphite (KS1) used as the negative electrode active material.
Acetylene black 4 in 86 parts by weight of 5, Lonza
Parts by weight and polyvinylidene fluoride (PVD) as a binder
F) 10 parts by weight was added and wet mixed with N-methyl-2-pyrrolidone as a solvent to form a slurry (paste form). This slurry is uniformly applied to both sides of a copper foil having a thickness of 0.01 mm as a current collector, dried and pressure-molded with a roller press machine to form a sheet-like electrode, and the electrode width is changed from this sheet-like electrode to 54 mm. A band-shaped negative electrode (1d) was prepared and then dried in a vacuum dryer at 100 ° C. for 12 hours.
【００１９】正極は実施例１で作成した、電極幅を５４
ｍｍに調整した帯状の正極（２）をここでも使用する。
帯状の負極（１ｄ）と正極（２）はその間に幅５８ｍｍ
の帯状の多孔質ポリプロピレン製セパレータ（３）を挟
んでロール状に巻き上げて、外径で１７．１ｍｍ、高さ
５８ｍｍの電池素子を作成した。The positive electrode was prepared in Example 1 and had an electrode width of 54.
The strip-shaped positive electrode (2) adjusted to mm is also used here.
The width of the strip-shaped negative electrode (1d) and the positive electrode (2) is 58 mm.
The strip-shaped porous polypropylene separator (3) was sandwiched and rolled up to form a battery element having an outer diameter of 17.1 mm and a height of 58 mm.
【００２０】ここではアルミニウム製の電池缶ではな
く、ニッケルメッキを施した鉄製の電池缶（４ｄ）を使
用し、電池缶（４ｄ）の底部に絶縁シート（１４）を設
置して上記電池素子を収納する。その後はすべて実施例
１と同じにして、図３に示す電池構造で、外径１８．１
ｍｍ、高さ６５ｍｍの従来型のリチウムイオン二次電池
（Ｄ）を作成した。Here, a nickel-plated iron battery can (4d) is used instead of an aluminum battery can, and an insulating sheet (14) is installed at the bottom of the battery can (4d) to install the battery element. Store. After that, the same procedure as in Example 1 was applied to the battery structure shown in FIG.
A conventional lithium ion secondary battery (D) having a size of 65 mm and a height of 65 mm was prepared.
【００２１】電池の充放電試験 こうして作成した電池（Ａ）〜（Ｄ）は電池内部の安定
化を目的に１２時間のエージング時間を経過させた後、
電池（Ａ）〜（Ｃ）は充電電圧３．０Ｖに設定し、８時
間の充電を行い、電池（Ｄ）は充電電圧４．２Ｖに設定
し、８時間の充電を行った。そのあと１００ｍＡの定電
流で終始電圧２．０Ｖまで放電を行ったところ、電池
（Ａ）〜（Ｄ）は何れも約１２５０ｍＡｈの容量が得ら
れた。その後同様な充放電を３回繰り返した。３回の充
放電において充電電圧、放電電圧、充電容量、放電容量
にはほとんど変化はなかった。図１に本発明による電池
の代表的充放電カーブを示す。充電後の電池電圧は、電
池（Ａ）〜（Ｃ）が約２．９Ｖであり、従来型リチウム
イオン二次電池（Ｄ）は４．１５Ｖで、本発明による電
池は従来型に比べ、１．２５Ｖも電圧が低いものであっ
た。これは本発明の電池の負極活物質は充電状態におい
てもリチウムがドープされたグラファイト（ＬｉＣ６）
に比べると１．２Ｖ以上も貴な電極電位であることを意
味する。しかし、容量×平均放電電圧÷電池体積からエ
ネルギー密度を計算すれば、電池（Ａ）〜（Ｃ）のエネ
ルギー密度は１８０ｗｈ／１であり、十分既存のニッケ
ルカドミウム電池のそれを上回るものである。Battery Charging / Discharging Test The batteries (A) to (D) thus prepared were subjected to an aging time of 12 hours for the purpose of stabilizing the inside of the battery, and then,
The batteries (A) to (C) were set to a charging voltage of 3.0V and charged for 8 hours, and the battery (D) was set to a charging voltage of 4.2V and charged for 8 hours. Then, when the battery was discharged at a constant current of 100 mA to a voltage of 2.0 V throughout, the batteries (A) to (D) each had a capacity of about 1250 mAh. After that, the same charge and discharge was repeated three times. The charge voltage, the discharge voltage, the charge capacity, and the discharge capacity were hardly changed in the three charge / discharge cycles. FIG. 1 shows a typical charge / discharge curve of the battery according to the present invention. The battery voltage after charging was about 2.9V for the batteries (A) to (C) and 4.15V for the conventional lithium-ion secondary battery (D). The voltage was as low as 0.25V. This is because the negative electrode active material of the battery of the present invention is lithium-doped graphite (LiC 6 ) even in a charged state.
It means that the electrode potential is as high as 1.2 V or more as compared with. However, when the energy density is calculated from the capacity × average discharge voltage / battery volume, the energy density of the batteries (A) to (C) is 180 wh / 1, which is sufficiently higher than that of the existing nickel-cadmium battery.
【００２２】各電池の安全試験（圧壊試験） 前述の充電方法にて完全充電をした後に電池（Ａ）〜
（Ｄ）は図４に示す装置で、本来の電池径の１／４の厚
さになるまで押しつぶして“電池の圧壊テスト”を行っ
た。図４は圧壊装置の原理を示すもので、直径１６ｍｍ
の丸棒（２２）が油圧プレス機で下降して、電池（３
０）を押しつぶすものである。各電池の圧壊テスト結果
は表１の通りである。従来のリチウムイオン二次電池の
負極活物質である炭素材料（グラファイト）を使用した
電池（Ｄ）は圧壊テストの結果、すべてが発火してしま
った。これは電池が押し潰されたとき、電池内部で内部
ショートが起こり、電池内の全ての電極で発電される電
流がショート個所に集中し、ショート個所ではショート
抵抗（Ｒ）とショート電流（Ｉ）の二乗との積 （Ｉ２
Ｒ）で発熱するため、局部的には非常に高温に達する。
高温に達した部分ではリチウムがドープされたグラファ
イト（ＬｉＣ６）は電解液と反応し、電池内温度はさら
に上昇し、正極活物質が分解して酸素を発生するため電
池内容物が燃焼して発火してしまう。 Safety test of each battery (crush test) After fully charging by the above-mentioned charging method, the battery (A) to
(D) is the device shown in FIG. 4, which was crushed to a thickness of ¼ of the original battery diameter to perform a “battery crush test”. Fig. 4 shows the principle of the crushing device, which has a diameter of 16 mm.
The round bar (22) of the
0) is crushed. Table 1 shows the results of the crush test of each battery. As for the battery (D) using the carbon material (graphite), which is the negative electrode active material of the conventional lithium ion secondary battery, all were ignited as a result of the crush test. This is because when the battery is crushed, an internal short circuit occurs inside the battery, and the current generated by all the electrodes in the battery is concentrated at the short points, and the short resistance (R) and short current (I) at the short points. The product of (I 2
Since it heats up in R), it reaches a very high temperature locally.
In the portion reaching the high temperature, the lithium-doped graphite (LiC 6 ) reacts with the electrolytic solution, the temperature inside the battery further rises, the positive electrode active material decomposes to generate oxygen, and the battery contents burn. It will catch fire.
【００２３】本発明による電池（Ａ）〜（Ｃ）も押し潰
されれば、電池内部で当然内部ショートは起こる。しか
し本発明の負極活物質は充電状態においても、リチウム
がドープされたグラファイト（ＬｉＣ６）に比べ１．２
Ｖ以上も貴な電極電位であるため、たとえショート箇所
が高温に達しても電解液とは反応しない。従って電池内
温度がさらに上昇することはなく、正極活物質は分解し
ない。電池内での酸素ガスは極めて少ない状態にあるた
め電池内容物が燃焼することはない。If the batteries (A) to (C) according to the present invention are also crushed, an internal short circuit naturally occurs inside the battery. However, the negative electrode active material of the present invention, even in a charged state, is 1.2 times thicker than lithium-doped graphite (LiC 6 ).
Since V is a noble electrode potential or more, even if the short-circuited portion reaches a high temperature, it does not react with the electrolytic solution. Therefore, the temperature inside the battery does not rise further and the positive electrode active material is not decomposed. Since the oxygen gas in the battery is extremely low, the battery contents will not burn.
【００２４】安全性試験（ホットボックス試験） 前記と同様な充電条件で充電を済ませた完全充電状態の
電池（Ａ）〜（Ｃ）をオーブン中に入れ、オーブンの温
度を徐々に上げて、オーブン温度が１６０℃に達した後
は、オーブンを一定温度（１６０℃）に２時間保った。
電池（Ａ）〜（Ｃ）には何れの電池においても発煙、発
火などは起こらなかった。Safety Test (Hot Box Test) Batteries (A) to (C) in a fully charged state, which have been charged under the same charging conditions as described above, are placed in an oven, the temperature of the oven is gradually raised, and the oven is heated. After the temperature reached 160 ° C, the oven was kept at a constant temperature (160 ° C) for 2 hours.
No smoke or ignition occurred in any of the batteries (A) to (C).
【００２５】一方本発明による電池との比較のため、前
記実施例での試作電池とほぼ同サイズ（１８６５０サイ
ズ）の市販のリチウムイオン二次電池（Ｘ）を入手し、
これについて同様の、高温での安全性テストを行った。
電池（Ｘ）は負極活物質として炭素材料が使用され、正
極活物質としてリチウムコバルト酸化物が使用されてい
るものである。まずこの電池（Ｘ）は充電電圧を４．２
Ｖに設定し、８時間の充電を行い、充電完了後２４時間
開路状態のまま放置した後、電池電圧を測定した。電池
電圧は４．１５Ｖであり、本発明による電池より１．２
５Ｖも高い開路電圧であった。その後、高温での安全性
テストを行った。前記同様（充電電圧４．２Ｖで充電時
間８時間）の充電条件で充電した完全充電状態の電池
（Ｘ）を、オーブン中に入れ、オーブンの温度を徐々に
上げていったところ、オーブン温度が１５５℃に達した
時点で、電池（Ｘ）は発火し、激しく発煙した。以上の
結果から本発明の電池は大きく安全性において改善され
ることがわかる。しかし電池（Ａ）は安全な電池として
の目的は達成されているが、せつかく正極活物質として
安価なリチウムマンガン酸化物を使用しているのに、負
極には高価なリチウムコバルト酸化物を使用しているの
で、安価なリチウムイオン二次電池の実現には適切では
ないかも知れない。その意味では電池（Ｂ）および電池
（Ｃ）が好ましいわけであるが、本発明のための負極活
物質は層状構造をもつ一般式ＬｉＡ１−ＸＢＸＯ２で示
される化合物であり、この化合物はＬｉＮｉＯ２、Ｌｉ
ＣｏＯ２、ＬｉＦｅＯ２の３つが基本的な化合物である
が、Ｎｉ３＋、Ｃｏ３＋、Ｆｅ３＋（つまり一般式中の
Ａ３＋）を他の３価のイオン（Ｂ３＋）で置換した形の
数多くの化合物が存在するので、より安価な材料を見い
だすことも可能である。On the other hand, for comparison with the battery according to the present invention, a commercially available lithium ion secondary battery (X) having substantially the same size (18650 size) as the prototype battery in the above-mentioned embodiment was obtained,
A similar high temperature safety test was performed on this.
The battery (X) uses a carbon material as the negative electrode active material and lithium cobalt oxide as the positive electrode active material. First, this battery (X) has a charging voltage of 4.2.
The battery voltage was set to V, charged for 8 hours, left open for 24 hours after the completion of charging, and then the battery voltage was measured. The battery voltage is 4.15V, which is 1.2 than the battery according to the present invention.
The open circuit voltage was as high as 5V. After that, a safety test was performed at high temperature. A fully charged battery (X) charged under the same charging conditions as above (charging voltage of 4.2 V and charging time of 8 hours) was placed in the oven, and the temperature of the oven was gradually raised. When the temperature reached 155 ° C, the battery (X) ignited and smoked violently. From the above results, it can be seen that the battery of the present invention is greatly improved in safety. However, although battery (A) has achieved the purpose of being a safe battery, it uses expensive lithium manganese oxide as the positive electrode active material, but uses expensive lithium cobalt oxide for the negative electrode. Therefore, it may not be suitable for realizing an inexpensive lithium-ion secondary battery. In that sense, the battery (B) and the battery (C) are preferable, but the negative electrode active material for the present invention is a compound represented by the general formula LiA 1-X B X O 2 having a layered structure. Compounds are LiNiO 2 , Li
CoO 2 and LiFeO 2 are three basic compounds, but many of them have Ni 3+ , Co 3+ , Fe 3+ (that is, A 3+ in the general formula) replaced with another trivalent ion (B 3+ ). It is also possible to find cheaper materials due to the existence of the compounds of
【００２６】[0026]
【発明の効果】以上のように市販のリチウムイオン二次
電池が１５５℃で発火してしまうのに対して、本発明に
よる電池は１６０℃に長時間保管されても安全である。
これまで、正極活物質にリチウムマンガン酸化物使用す
るリチウムイオン二次電池は、リチウムコバルト酸化物
を正極活物質とする電池に比べ、性能がやや低いと言う
理由で、性能優先の用途には特徴を発揮できなかった。
しかし負極活物質として層状構造をもつ一般式ＬｉＡ
１−ＸＢＸＯ２で示される化合物を使用することによ
り、従来の炭素材料を負極活物質とするリチウムイオン
二次電池に比べて、放電電圧が適度に低くなるため、高
温状態での安全性が高くなり、且つエネルギー密度も１
８０ｗｈ／ｌ以上は確保されるので、安全性能と電池性
能がよくバランスした安価なリチウムイオン二次電池が
実現する。この結果、広範囲な用途で既存の電池に代わ
って使用できる、無公害で、高容量の二次電池が提供で
きるようになり、その工業的価値は大である。As described above, the commercially available lithium ion secondary battery ignites at 155 ° C, whereas the battery according to the present invention is safe even if stored at 160 ° C for a long time.
So far, lithium-ion secondary batteries that use lithium manganese oxide as the positive electrode active material are characterized by slightly lower performance than batteries that use lithium cobalt oxide as the positive electrode active material. Could not be demonstrated.
However, the general formula LiA having a layered structure as the negative electrode active material
By using a compound represented by 1-X B X O 2, as compared to the lithium ion secondary battery using the conventional carbon material as the negative electrode active material, the discharge voltage is appropriately low, safety in a high temperature state And the energy density is 1
Since 80 wh / l or more is secured, an inexpensive lithium-ion secondary battery in which safety performance and battery performance are well balanced is realized. As a result, it is possible to provide a pollution-free, high-capacity secondary battery that can be used in place of existing batteries in a wide range of applications, and its industrial value is great.
【図１】電池の充放電カーブ。FIG. 1 is a battery charge / discharge curve.
【図２】巻回電極構造の電池素子断面図。FIG. 2 is a cross-sectional view of a battery element having a wound electrode structure.
【図３】円筒型電池の模式的断面図。FIG. 3 is a schematic cross-sectional view of a cylindrical battery.
【図４】圧壊装置の原理図[Figure 4] Principle diagram of crushing device
１は負極、２は正極、３はセパレータ、４は電池缶、５
は負極リード、６はガスケット、７は正極リード、８は
防爆弁、１４は絶縁シート、２２は圧壊丸棒、３０は試
験電池である。1 is a negative electrode, 2 is a positive electrode, 3 is a separator, 4 is a battery can, 5
Is a negative electrode lead, 6 is a gasket, 7 is a positive electrode lead, 8 is an explosion-proof valve, 14 is an insulating sheet, 22 is a crushing round bar, and 30 is a test battery.
─────────────────────────────────────────────────────
─────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成７年３月２８日[Submission date] March 28, 1995
【手続補正１】[Procedure Amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】特許請求の範囲[Name of item to be amended] Claims
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【特許請求の範囲】[Claims]
Claims (1)
酸化物を使用する非水電解液二次電池において、一般式
ＬｉＡ１−ＸＢＸＯ２（但し、ＡはＮｉ、Ｃｏ、Ｆｅの
何れかであり、ＢはＡと置換された３価のイオンであ
り、Ｏ≦Ｘ≦０．５）で示されるリチウム含有遷移金属
複合酸化物が負極活物質として使用されることを特徴と
する非水電解液二次電池。1. A non-aqueous electrolyte secondary battery using a spinel type lithium manganese oxide as a positive electrode active material, wherein LiA 1-X B X O 2 (where A is any of Ni, Co and Fe). And B is a trivalent ion substituted with A, and a lithium-containing transition metal composite oxide represented by O ≦ X ≦ 0.5) is used as a negative electrode active material. Electrolyte secondary battery.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7085874A JPH08241717A (en) | 1995-03-06 | 1995-03-06 | Secondary battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7085874A JPH08241717A (en) | 1995-03-06 | 1995-03-06 | Secondary battery |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08241717A true JPH08241717A (en) | 1996-09-17 |
Family
ID=13871052
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7085874A Pending JPH08241717A (en) | 1995-03-06 | 1995-03-06 | Secondary battery |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08241717A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009301893A (en) * | 2008-06-13 | 2009-12-24 | Ntt Docomo Inc | Battery testing device and battery testing method |
| JP2011129269A (en) * | 2009-12-15 | 2011-06-30 | Toyota Central R&D Labs Inc | Anode electrode active material for nonaqueous secondary battery, nonaqueous secondary battery, and using method |
| CN103915647A (en) * | 2014-03-31 | 2014-07-09 | 上虞安卡拖车配件有限公司 | Low-temperature lithium ion battery |
| US10818969B2 (en) | 2018-09-27 | 2020-10-27 | University Of Maryland, College Park | Borate compounds as Li super-ionic conductor, solid electrolyte, and coating layer for Li metal battery and Li-ion battery |
-
1995
- 1995-03-06 JP JP7085874A patent/JPH08241717A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009301893A (en) * | 2008-06-13 | 2009-12-24 | Ntt Docomo Inc | Battery testing device and battery testing method |
| JP2011129269A (en) * | 2009-12-15 | 2011-06-30 | Toyota Central R&D Labs Inc | Anode electrode active material for nonaqueous secondary battery, nonaqueous secondary battery, and using method |
| CN103915647A (en) * | 2014-03-31 | 2014-07-09 | 上虞安卡拖车配件有限公司 | Low-temperature lithium ion battery |
| US10818969B2 (en) | 2018-09-27 | 2020-10-27 | University Of Maryland, College Park | Borate compounds as Li super-ionic conductor, solid electrolyte, and coating layer for Li metal battery and Li-ion battery |
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