JPH0855636A - Lithium secondary battery - Google Patents

Lithium secondary battery

Info

Publication number
JPH0855636A
JPH0855636A JP6209096A JP20909694A JPH0855636A JP H0855636 A JPH0855636 A JP H0855636A JP 6209096 A JP6209096 A JP 6209096A JP 20909694 A JP20909694 A JP 20909694A JP H0855636 A JPH0855636 A JP H0855636A
Authority
JP
Japan
Prior art keywords
battery
lithium
discharge
comparative example
discharged
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
Application number
JP6209096A
Other languages
Japanese (ja)
Inventor
Keiichi Saito
景一 斉藤
Shinichi Tobishima
真一 鳶島
Junichi Yamaki
準一 山木
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.)
Nippon Telegraph and Telephone Corp
Original Assignee
Nippon Telegraph and Telephone 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 Nippon Telegraph and Telephone Corp filed Critical Nippon Telegraph and Telephone Corp
Priority to JP6209096A priority Critical patent/JPH0855636A/en
Publication of JPH0855636A publication Critical patent/JPH0855636A/en
Pending 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
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

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  • Secondary Cells (AREA)

Abstract

PURPOSE:To provide high discharge characteristic from the first stage of use, lengthen the charge/discharge life, and enhance safety by conducting discharge at least once and storing for a certain period before use of a battery manufactured. CONSTITUTION:A lithium secondary battery is constituted with a negative electrode using lithium or a lithium alloy as an active material, a positive electrode capable of insetting and releasing a lithium ion, and an electrolyte prepared by dissolving a lithium salt which is difficult to dissociate into an ion in a nonaqueous solvent. The battery is discharged at least once and stored for a certain period before use. By conducting discharge once, a naturally formed protecting film on the surface of the negative electrode is broken, and a pure lithium metal surface appears. This lithium metal surface comes in contact with the electrolyte, and a stable protecting film is formed on the negative electrode. This protecting film is formed by storing in the electrolyte for a certain period. By using the battery which is discharged once and stored for a certain period, the battery provides high discharge performance from the first period, long charge/discharge life, and high safety.

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、リチウム金属ある
いはリチウム合金負極を用い、リチウムイオンを挿入、
脱離可能な正極とし、非水電解液を用いるリチウム二次
電池に関するものである。TECHNICAL FIELD The present invention uses a lithium metal or lithium alloy negative electrode and inserts lithium ions.
The present invention relates to a lithium secondary battery that uses a non-aqueous electrolyte as a removable positive electrode.

【０００２】[0002]

【従来の技術】電子機器の小型軽量化、携帯化が進み、
その電源として高エネルギー密度電池の開発が要求され
ている。このような要求に答える電池として、負極にリ
チウムを活物質とした充放電可能な高性能二次電池の開
発が期待されている。リチウムを活物質とした負極とし
ては、例えば、リチウム金属、リチウム金属合金、ある
いは、リチウムイオンを挿入、放出可能な化学物質（例
えば、種々の炭素材料、Ｎｂ2Ｏ5、ＷＯ3等）を用いる
ことが試みられているが、原理的に最も高いエネルギー
密度を有する負極は、リチウム金属を基本とした負極で
ある。本明細書では、以後リチウムを負極活物質とした
リチウム金属あるいはリチウム合金負極を用い、リチウ
ムイオンを挿入および脱離可能な正極および非水溶媒に
イオン解離性のリチウム塩を溶解した電解液を有し、充
放電可能な電池をリチウム二次電池と称する。2. Description of the Related Art As electronic devices are becoming smaller and lighter and portable,
Development of a high energy density battery is required as the power source. As a battery that meets such demands, it is expected to develop a high performance rechargeable battery that uses lithium as an active material for the negative electrode and can be charged and discharged. As the negative electrode using lithium as an active material, for example, lithium metal, a lithium metal alloy, or a chemical substance capable of inserting and releasing lithium ions (for example, various carbon materials, Nb 2 O 5 , WO 3 etc.) is used. However, the negative electrode having the highest energy density in principle is a lithium metal-based negative electrode. In the present specification, hereinafter, a lithium metal or lithium alloy negative electrode having lithium as a negative electrode active material is used, and a positive electrode capable of inserting and releasing lithium ions and an electrolytic solution in which an ion dissociable lithium salt is dissolved in a non-aqueous solvent are used. The battery that can be charged and discharged is called a lithium secondary battery.

【０００３】リチウム二次電池には、基本性能として
（ｉ）エネルギーが高いこと（ｉｉ）充放電サイクル寿
命が長いことの２点が要求される。この要求に答えるた
めに、多くの正極材料が検討されてきた。例えば、結晶
質、あるいは非晶質のＶ2Ｏ5（ａ−Ｖ2Ｏ5）、Ｖ
6Ｏ13、ＬｉxＶ3Ｏ8、ＭｎＯ2、ＬｉＣｏＯ2、ＬｉＮｉ
Ｏ2、ＭｏＯ3、等の金属酸化物、ＭｏＳ2、ＴｉＳ2等の
金属硫化物、ＮｂＳｅ3等の金属硫化物、ポリアニリ
ン、ポリピロール等の高分子化合物、ＳＯ2等の硫黄化
合物が提案されている。Lithium secondary batteries are required to have two basic performances: (i) high energy (ii) long charge / discharge cycle life. Many positive electrode materials have been investigated to meet this demand. For example, crystalline or amorphous V 2 O 5 (a-V 2 O 5 ), V
6 O 13 , Li x V 3 O 8 , MnO 2 , LiCoO 2 , LiNi
Metal oxides such as O 2 and MoO 3 , metal sulfides such as MoS 2 and TiS 2 , metal sulfides such as NbSe 3 , polymer compounds such as polyaniline and polypyrrole, and sulfur compounds such as SO 2 have been proposed. There is.

【０００４】これら負極、正極活物質などにより電池を
作成した後、電池使用前（商品とすれば出荷前）に、電
池を１回、放電あるいは充放電することが必要である。
この放電あるいは充放電をプレサイクルとよび、この処
理により電池の製造欠陥品の検査を行なう。通常、正極
へのリチウムの挿入反応を効率的に行なうため、０．５
ｍＡ／ｃｍ2以下の低い電流密度で電池を放電する。し
かし、負極側から考えた場合、０．５ｍＡ／ｃｍ2以下
の低い放電電流密度で放電を行なった場合、負極表面に
針状リチウム（デンドライト）が生成する。このデンド
ライトの成長によって、（ｉ）正極と負極を電気的に絶
縁しているセパレータを突き破り、内部ショートを引き
起こす危険性が高くなる、（ｉｉ）リチウム極の表面積
が増すことで、電解液などの電池構成物との反応性が高
くなる。It is necessary to discharge or charge the battery once after using the negative electrode, the positive electrode active material, etc., and before using the battery (before shipping as a product).
This discharging or charging / discharging is called a pre-cycle, and this process is used to inspect defective batteries for manufacturing. Usually, in order to efficiently perform the lithium insertion reaction into the positive electrode, 0.5
The battery is discharged at a low current density of mA / cm 2 or less. However, when considered from the negative electrode side, acicular lithium (dendrites) are generated on the negative electrode surface when discharging is performed at a low discharge current density of 0.5 mA / cm 2 or less. The growth of this dendrite increases the risk of (i) breaking through the separator that electrically insulates the positive electrode and the negative electrode and causing an internal short circuit. (Ii) The surface area of the lithium electrode increases, and Increased reactivity with battery components.

【０００５】リチウム二次電池は、強還元剤である負
極、強酸化剤である正極、引火性の液体であり、かつ加
熱分解あるいは電気化学的分解で可燃性ガスを放出しや
すい非水電解液などの化学物質を密封容器に入れた構造
を持つため、発炎、発火の潜在的な危険性を有してお
り、このようなデンドライト成長によって安全性の低下
が助長される。このようなデンドライトの生成は、以下
の述べるような過程によって生じる。通常、リチウム負
極の表面には自然保護膜とよばれる電気絶縁性のリチウ
ムの酸化物、炭酸化物、水酸化物などを主成分とする強
固な固体表面膜が存在する。電池の放電によってこの膜
を破壊し、純粋なリチウム表面が現われるが、０．５ｍ
Ａ／ｃｍ2以下のような低い電流密度では、この自然保
護膜の電気抵抗が低い部分（例えば、表面膜の薄い部
分）に集中してリチウムイオンの放電が生じ、その部分
だけに深い穴が開いたような形状を作り出す。その後の
充電では、その部分以外は、絶縁性の自然保護膜がある
ので、この凹部に優先的に電析が起こり、リチウムの析
出形態が平滑性を失い、デンドライトの発生が顕著にな
ると考えられている。さらにこのデンドライトの発生が
顕著になると、デンドライトが負極表面から剥離し、負
極表面との電気的コンタクトを失い、充放電に使用でき
なくなる。このことから電池寿命の低下が生じる。A lithium secondary battery is a non-aqueous electrolyte which is a negative electrode which is a strong reducing agent, a positive electrode which is a strong oxidizing agent, a flammable liquid, and which easily releases a flammable gas by thermal decomposition or electrochemical decomposition. Since it has a structure in which chemical substances such as are put in a sealed container, there is a potential risk of flame and ignition, and such dendrite growth promotes a decrease in safety. The generation of such dendrites occurs by the process described below. Usually, on the surface of the lithium negative electrode, there is a strong solid surface film mainly composed of electrically insulating lithium oxide, carbonate, hydroxide or the like, which is called a natural protective film. When the battery is discharged, this film is destroyed, and a pure lithium surface appears, but 0.5m
At a low current density such as A / cm 2 or less, the lithium ion discharge is concentrated in a portion where the electric resistance of the natural protective film is low (for example, a thin portion of the surface film), and a deep hole is formed only in that portion. Create an open shape. In subsequent charging, since there is an insulating natural protective film other than that part, electrodeposition occurs preferentially in this concave portion, the lithium deposition form loses smoothness, and dendrite generation is considered to be remarkable. ing. Further, when the generation of dendrites becomes remarkable, the dendrites are separated from the surface of the negative electrode and lose electrical contact with the surface of the negative electrode, so that they cannot be used for charging and discharging. This causes a decrease in battery life.

【０００６】このように電池使用前（商品とすれば出荷
前）に、電池を１回、放電あるいは充放電する際に、正
極での要求として低電流で放電しなければならないが、
一方負極の表面状態を良好にし、安全性を確保し、電池
寿命を良好にするためには、低電流での放電は避けなけ
ればならない。As described above, when the battery is discharged or charged / discharged once before the battery is used (commercial products are shipped), it must be discharged at a low current as required by the positive electrode.
On the other hand, in order to improve the surface condition of the negative electrode, ensure safety, and improve battery life, it is necessary to avoid discharge at low current.

【０００７】[0007]

【発明の目的】本発明は、このような現状に鑑みたもの
であり、電池使用前の充放電時において低電流放電でも
負極の表面状態を良好に保ち、生じる安全性の低下の防
止、電池寿命の低下の防止を目的としている。SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is possible to maintain a good surface condition of the negative electrode even during low current discharge during charge / discharge before use of the battery, and prevent a decrease in safety caused by the battery. The purpose is to prevent the shortening of life.

【０００８】[0008]

【発明の特徴と従来の技術との差異】本発明による電池
は、負極にリチウム金属を用いたリチウム二次電池にお
いて、電池使用前に放電を少なくとも１回行なった電池
を一定期間保管した後に使用することを特徴とする二次
電池である。Features of the Invention and Differences from Prior Art The battery according to the present invention is a lithium secondary battery using lithium metal as a negative electrode, and is used after being stored for a certain period of time after being discharged at least once before using the battery. The secondary battery is characterized in that

【０００９】本発明をさらに詳しく説明する。The present invention will be described in more detail.

【００１０】本発明によるリチウム二次電池は、電池使
用前に少なくとも１回行なった電池を一定期間保管した
後に使用することを特徴とする。The lithium secondary battery according to the present invention is characterized in that the battery is used at least once before being used, after being stored for a certain period of time.

【００１１】放電を少なくとも１回施すことにより負極
表面を覆っていた自然保護膜が破壊され、純粋なリチウ
ム金属が現われる。好ましくは、放電、充電のサイクル
を２回繰り返し、完全に自然保護膜を破壊することが望
ましい。純粋なリチウム金属面は、電解液と接触してい
るために電解液との安定した保護膜が形成される。この
ような電解液と負極との安定した保護膜は一定期間の保
管によって得られる。好ましくは室温から４５℃の範囲
で１日以上であり、さらに好ましくは室温で１週間以
上、あるいは４５℃で３日間以上の保管が望ましい。こ
の電解液との安定した保護膜は自然保護膜に比べ、均質
で柔軟性に富むために０．５ｍＡ／ｃｍ2以下のような
低い電流密度で放電した際にも、負極表面での電流の集
中が生じにくく、負極表面の平滑性が損なわれない。By applying the discharge at least once, the natural protective film covering the negative electrode surface is destroyed, and pure lithium metal appears. It is preferable that the cycle of discharging and charging is repeated twice to completely destroy the natural protective film. Since the pure lithium metal surface is in contact with the electrolytic solution, a stable protective film with the electrolytic solution is formed. Such a stable protective film of the electrolytic solution and the negative electrode can be obtained by storage for a certain period. It is preferably stored at room temperature to 45 ° C. for 1 day or longer, more preferably at room temperature for 1 week or longer, or at 45 ° C. for 3 days or longer. The stable protective film with this electrolyte is more homogeneous and flexible than the natural protective film, so current concentration on the negative electrode surface occurs even when discharged at a low current density of 0.5 mA / cm 2 or less. Is less likely to occur and the smoothness of the negative electrode surface is not impaired.

【００１２】このようなリチウム金属の電解液との接触
によって得られる保護膜は安定した膜であることが望ま
しく、電解液に用いる非水溶媒としては、プロピレンカ
ーボネート、エチレンカーボネート、γ−ブチロラクト
ン等の環状エステル、ジメチルカーボネート、ジエチル
カーボネート等の非環状エステル、テトラヒドロフラ
ン、２−メチルテトラヒドロフラン、１．３−ジオキソ
ラン、４−メチル−１．３−ジオキソラン等の環状エー
テル、ジアルコキシエタン、グライム類等の非環状エー
テル、スルホラン等の硫黄化合物等を単独もしくは２種
類以上混合して用いることができる。そのうちエチレン
カーボネートを含むことが望ましく、さらにエーテル類
あるいはエステル類の電解液を混合して使用し、さらに
エーテル類あるいはエステル類の好ましくは２−メチル
テトラヒドロフラン、プロピレンカーボネート、ジメチ
ルカーボネートを含むことが望ましい。The protective film obtained by contacting the lithium metal with the electrolytic solution is preferably a stable film, and the non-aqueous solvent used for the electrolytic solution is propylene carbonate, ethylene carbonate, γ-butyrolactone or the like. Cyclic ester, non-cyclic ester such as dimethyl carbonate, diethyl carbonate, cyclic ether such as tetrahydrofuran, 2-methyltetrahydrofuran, 1.3-dioxolane, 4-methyl-1.3-dioxolane, dialkoxyethane, non-constant such as glymes. Sulfur compounds such as cyclic ethers and sulfolane can be used alone or in admixture of two or more. Among them, it is desirable to contain ethylene carbonate, further to use by mixing with an electrolyte solution of ethers or esters, and it is desirable to further contain 2-methyltetrahydrofuran, propylene carbonate or dimethyl carbonate of ethers or esters.

【００１３】このことから電池使用前（商品とすれば出
荷前）に、電池を１回、放電あるいは充放電する際に低
い電流密度での放電が可能となり、安定した正極を作り
出しつつ、負極表面の平滑性を保ち、熱安定性に優れた
電池が作成できる。Therefore, before use of the battery (before shipment as a product), the battery can be discharged once at a low current density when discharged or charged / discharged, and a stable positive electrode is produced while the negative electrode surface is produced. It is possible to create a battery that maintains the smoothness of the above and has excellent thermal stability.

【００１４】本発明のリチウム二次電池の正極として
は、例えばＬｉxＣｏＯ2（０≦ｘ≦１）、ＬｉxＮｉＯ2
（０≦ｘ≦１）、ＬｉxＭｎ2Ｏ4（０≦ｘ≦１）、結晶
あるいは非結晶のＶ2Ｏ5、ＬｉxＶ3Ｏ8（０＜ｘ≦
１）、ＴｉＳ2、ＮｂＳｅ3等を用いることができる。ま
た、電解液に用いるリチウム塩としては、例えばＬｉＡ
ｓＦ6、ＬｉＰＦ6、ＬｉＳｂＦ6、ＬｉＣＦ3ＳＯ3、Ｌ
ｉＮ（ＣＦ3ＳＯ2）2、ＬｉＣ（ＣＦ3ＳＯ2）3、ＬｉＣ
ｌＯ4、ＬｉＢＦ4、ＬｉＡｌＣｌ4等を用いることがで
きる。Examples of the positive electrode of the lithium secondary battery of the present invention include Li x CoO 2 (0 ≦ x ≦ 1), Li x NiO 2
(0 ≦ x ≦ 1), Li x Mn 2 O 4 (0 ≦ x ≦ 1), crystalline or amorphous V 2 O 5 , Li x V 3 O 8 (0 <x ≦
1), TiS 2 , NbSe 3 or the like can be used. The lithium salt used in the electrolytic solution is, for example, LiA.
sF 6 , LiPF 6 , LiSbF 6 , LiCF 3 SO 3 , L
iN (CF 3 SO 2 ) 2 , LiC (CF 3 SO 2 ) 3 , LiC
10 4 , LiBF 4 , LiAlCl 4 or the like can be used.

【００１５】[0015]

【比較例１】負極として、リチウム金属、正極としてａ
−Ｖ2Ｏ5を活物質とし、電解液として１モル／ｌのＬｉ
ＡｓＦ6をエチレンカーボネートとプロピレンカーボネ
ートの混合溶媒（体積混合比、１：１）に溶解したもの
を用いて、単三型電池を作製した。この電池のプレサイ
クルとして０．５ｍＡ／ｃｍ2の放電電流密度で１．５
Ｖまで放電し０．４ｍＡ／ｃｍ2で３．３Ｖまで充電す
る操作を行なった電池を、即座に放電電流密度３ｍＡ／
ｃｍ2にて１．５Ｖまで放電、充電電流密度０．４ｍＡ
／ｃｍ2で３．３Ｖまで充電する操作を１サイクルとし
た充放電サイクルを繰り返した。その際の電池の規格化
した放電容量とサイクル数の関係を参考として図１およ
び図２に示す。なお、図中、縦軸の放電容量はそれぞれ
の電池の初期放電容量を１として規格化したものであ
る。Comparative Example 1 Lithium metal is used as the negative electrode and a is used as the positive electrode.
-V 2 O 5 as an active material and 1 mol / l of Li as an electrolytic solution
AA-sized batteries were produced using AsF 6 dissolved in a mixed solvent of ethylene carbonate and propylene carbonate (volume mixing ratio: 1: 1). As a pre-cycle of this battery, the discharge current density of 0.5 mA / cm 2 was 1.5.
Immediately after discharging the battery discharged to V to 0.4V / cm 2 to 3.3V, the discharge current density was 3mA /
Discharge up to 1.5 V at cm 2 , charging current density 0.4 mA
The charging / discharging cycle was repeated with the operation of charging to 3.3 V at 1 / cm 2 as one cycle. The normalized discharge capacity of the battery and the number of cycles at that time are shown in FIGS. 1 and 2 for reference. In the figure, the discharge capacity on the vertical axis is standardized with the initial discharge capacity of each battery being 1.

【００１６】[0016]

【比較例２】負極として、リチウム金属、正極としてａ
−Ｖ2Ｏ5を活物質とし、電解液として１モル／ｌのＬｉ
ＡｓＦ6をプロピレンカーボネートに溶解したものを用
いて、単三型電池を作製した。この電池のプレサイクル
として０．５ｍＡ／ｃｍ2の放電電流密度で１．５Ｖま
で放電し０．８ｍＡ／ｃｍ2で３．３Ｖまで充電する操
作を行なった電池を、即座に丸棒で電池中心部を電池直
径の５％になるまで押し潰す試験を行なった。その際の
試験結果について、表１に示す。押し潰しの際に、電池
正極蓋から火花が確認された。結果として発火、爆発に
は至らなかったが、電池内部には燃焼性の物質が究めて
多く、この火花による引火の可能性も否めない。[Comparative Example 2] Lithium metal as the negative electrode and a as the positive electrode
-V 2 O 5 as an active material and 1 mol / l of Li as an electrolytic solution
AA batteries were prepared using AsF 6 dissolved in propylene carbonate. Cell around a battery was subjected to operations of charging at 0.8 mA / cm 2 was discharged at a discharge current density of 0.5 mA / cm 2 to 1.5V as a pre-cycle of the battery until 3.3V, immediately a round bar A test was conducted to crush the part to 5% of the battery diameter. The test results at that time are shown in Table 1. Sparks were confirmed from the battery positive electrode lid during crushing. As a result, no ignition or explosion occurred, but there is a large amount of combustible substances inside the battery, and the possibility of ignition due to this spark cannot be denied.

【００１７】[0017]

【比較例３】負極として、リチウム金属、正極としてａ
−Ｖ2Ｏ5を活物質とし、電解液として１モル／ｌのＬｉ
ＡｓＦ6をエチレンカーボネートと２メチルテトラヒド
ロフランの混合溶媒（体積混合比、１：１）に溶解した
ものを用いて、単三型電池を作製した。この電池のプレ
サイクルとして０．５ｍＡ／ｃｍ2の放電電流密度で
１．５Ｖまで放電し０．８ｍＡ／ｃｍ2で３．３Ｖまで
充電する操作を行なった電池を、即座に丸棒で電池中心
部を電池直径の５％になるまで押し潰す試験を行なっ
た。その際の試験結果について、表１に示す。押し潰し
の際に、電池正極蓋から火花が確認された。Comparative Example 3 Lithium metal is used as the negative electrode and a is used as the positive electrode.
-V 2 O 5 as an active material and 1 mol / l of Li as an electrolytic solution
A single AA battery was produced using AsF 6 dissolved in a mixed solvent of ethylene carbonate and 2-methyltetrahydrofuran (volume mixing ratio: 1: 1). Cell around a battery was subjected to operations of charging at 0.8 mA / cm 2 was discharged at a discharge current density of 0.5 mA / cm 2 to 1.5V as a pre-cycle of the battery until 3.3V, immediately a round bar A test was conducted to crush the part to 5% of the battery diameter. The test results at that time are shown in Table 1. Sparks were confirmed from the battery positive electrode lid during crushing.

【００１８】[0018]

【比較例４】負極として、リチウム金属、正極としてａ
−Ｖ2Ｏ5を活物質とし、電解液として１モル／ｌのＬｉ
ＰＦ6をエチレンカーボネートとジメチルカーボネート
の混合溶媒（体積混合比、１：１）に溶解したものを用
いて、単三型電池を作製した。この電池のプレサイクル
として０．５ｍＡ／ｃｍ2の放電電流密度で１．５Ｖま
で放電し０．８ｍＡ／ｃｍ2で３．３Ｖまで充電する操
作を行なった電池を、即座に丸棒で電池中心部を電池直
径の５％になるまで押し潰す試験を行なった。その際の
試験結果について、表１に示す。押し潰しの際に、電池
正極蓋から火花が確認された。Comparative Example 4 Lithium metal is used as the negative electrode and a is used as the positive electrode.
-V 2 O 5 as an active material and 1 mol / l of Li as an electrolytic solution
AA-type batteries were prepared using PF 6 dissolved in a mixed solvent of ethylene carbonate and dimethyl carbonate (volume mixing ratio: 1: 1). Cell around a battery was subjected to operations of charging at 0.8 mA / cm 2 was discharged at a discharge current density of 0.5 mA / cm 2 to 1.5V as a pre-cycle of the battery until 3.3V, immediately a round bar A test was conducted to crush the part to 5% of the battery diameter. The test results at that time are shown in Table 1. Sparks were confirmed from the battery positive electrode lid during crushing.

【００１９】[0019]

【比較例５】負極として、リチウム金属、正極としてＬ
ｉＭｎ2Ｏ4を活物質とし、電解液として１モル／ｌのＬ
ｉＰＦ6をエチレンカーボネートとジメチルカーボネー
トの混合溶媒（体積混合比、１：１）に溶解したものを
用いて、単三型電池を作製した。この電池のプレサイク
ルとして０．５ｍＡ／ｃｍ2の放電電流密度で１．５Ｖ
まで放電し０．８ｍＡ／ｃｍ2で３．３Ｖまで充電する
操作を行なった電池を、即座に丸棒で電池中心部を電池
直径の５％になるまで押し潰す試験を行なった。その際
の試験結果について、表１に示す。押し潰しの際に、電
池正極蓋から火花が確認された。[Comparative Example 5] Lithium metal as the negative electrode and L as the positive electrode
iMn 2 O 4 was used as an active material, and 1 mol / l of L was used as an electrolyte.
An AA battery was prepared using iPF 6 dissolved in a mixed solvent of ethylene carbonate and dimethyl carbonate (volume mixing ratio: 1: 1). As a pre-cycle of this battery, 1.5 V at a discharge current density of 0.5 mA / cm 2.
The battery was discharged to 0.8 V / cm 2 and charged to 3.3 V, and a test was carried out by immediately crushing the center of the battery with a round bar to 5% of the battery diameter. The test results at that time are shown in Table 1. Sparks were confirmed from the battery positive electrode lid during crushing.

【００２０】[0020]

【実施例１−１】比較例１と同様の単三型電池を作製
し、比較例１と同様のプレサイクルを行なった後、室温
で１２時間保管した後に、放電電流密度３ｍＡ／ｃｍ2
にて１．５Ｖまで放電、充電電流密度０．４ｍＡ／ｃｍ
2で３．３Ｖまで充電する操作を１サイクルとした充放
電サイクルを繰り返した。その際の電池の規格化した放
電容量とサイクル数の関係を図１に、符号１−１として
示す。比較例１に比べ、実施例１−１は、サイクル寿命
が向上していることが明らかである。また、最大放電容
量に達するまでのサイクル数が比較例１に比べ短く、電
池使用初期から良好な放電特性を有することが明かとな
った。Example 1-1 An AA battery similar to that of Comparative Example 1 was produced, subjected to the same pre-cycle as that of Comparative Example 1, and then stored at room temperature for 12 hours, after which the discharge current density was 3 mA / cm 2.
Discharge up to 1.5V, charging current density 0.4mA / cm
The charging / discharging cycle was repeated with the operation of charging 2 to 3.3V as one cycle. The relationship between the standardized discharge capacity of the battery and the number of cycles in that case is shown as reference numeral 1-1 in FIG. It is clear that in Example 1-1, the cycle life is improved as compared with Comparative Example 1. Further, it was revealed that the number of cycles until the maximum discharge capacity was reached was shorter than that in Comparative Example 1, and that the battery had good discharge characteristics from the initial use of the battery.

【００２１】[0021]

【実施例１−２】比較例１と同様の単三型電池を作製
し、比較例１と同様のプレサイクルを行なった後、４５
℃で１２時間保管した後に、放電電流密度３ｍＡ／ｃｍ
2にて１．５Ｖまで放電、充電電流密度０．４ｍＡ／ｃ
ｍ2で３．３Ｖまで充電する操作を１サイクルとした充
放電サイクルを繰り返した。その際の電池の規格化した
放電容量とサイクル数の関係を図２に、符号２−２とし
て示す。比較例１に比べ、実施例１−２は、サイクル寿
命が向上していることが明らかである。また、最大放電
容量に達するまでのサイクル数が比較例１に比べ短く、
電池使用初期から良好な放電特性を有することが明かと
なった。[Example 1-2] An AA battery similar to that of Comparative Example 1 was prepared and subjected to the same pre-cycle as Comparative Example 1, and then 45
Discharge current density 3mA / cm after storage at ℃ for 12 hours
Discharge up to 1.5V at 2 , charging current density 0.4mA / c
The charging / discharging cycle was repeated with the operation of charging to 3.3 V at m 2 as one cycle. The relationship between the standardized discharge capacity of the battery and the number of cycles in that case is shown as reference numeral 2-2 in FIG. It is clear that, as compared with Comparative Example 1, Example 1-2 has improved cycle life. In addition, the number of cycles until reaching the maximum discharge capacity is shorter than in Comparative Example 1,
It has been revealed that the battery has good discharge characteristics from the beginning of use of the battery.

【００２２】[0022]

【実施例１−３】比較例１と同様の単三型電池を作製
し、比較例１と同様のプレサイクルを行なった後、室温
で１ヵ月保管した後に比較例１と同様の充放電サイクル
を行なった。その際の電池の規格化した放電容量とサイ
クル数の関係を図１に、符号１−３として示す。比較例
１に比べ、実施例１−３は、飛躍的にサイクル寿命が向
上していることが明らかである。また、最大放電容量に
達するまでのサイクル数が比較例１に比べ短く、電池使
用初期から良好な放電特性を有することが明かとなっ
た。Example 1-3 An AA battery similar to that of Comparative Example 1 was prepared, subjected to the same pre-cycle as that of Comparative Example 1, and then stored at room temperature for 1 month, and then the same charge / discharge cycle as that of Comparative Example 1 was performed. Was done. The relationship between the standardized discharge capacity of the battery and the number of cycles in that case is shown as reference numeral 1-3 in FIG. It is clear that in Examples 1-3, the cycle life is dramatically improved as compared with Comparative Example 1. Further, it was revealed that the number of cycles until the maximum discharge capacity was reached was shorter than that in Comparative Example 1, and that the battery had good discharge characteristics from the initial use of the battery.

【００２３】[0023]

【実施例１−４】比較例１と同様の単三型電池を作製し
比較例１と同様のプレサイクルを行なった後、室温で１
日間保管した後に比較例１と同様の充放電サイクルを行
なった。その際の電池の規格化した放電容量とサイクル
数の関係を図２に、符号１−４として示す。比較例１に
比べ、実施例１−４は、サイクル寿命が向上しているこ
とが明らかである。また、最大放電容量に達するまでの
サイクル数が比較例１に比べ短く、電池使用初期から良
好な放電特性を有することが明かとなった。[Examples 1-4] An AA battery similar to that of Comparative Example 1 was prepared, and a pre-cycle similar to that of Comparative Example 1 was performed.
After storage for one day, the same charge / discharge cycle as in Comparative Example 1 was performed. The relationship between the standardized discharge capacity of the battery and the number of cycles at that time is shown as reference numeral 1-4 in FIG. It is clear that in Examples 1-4, the cycle life is improved as compared with Comparative Example 1. Further, it was revealed that the number of cycles until the maximum discharge capacity was reached was shorter than that in Comparative Example 1, and that the battery had good discharge characteristics from the initial use of the battery.

【００２４】[0024]

【実施例１−５】比較例１と同様の単三型電池を作製
し、比較例１と同様のプレサイクルを行なった後、４５
℃で１日間保管した後に比較例１と同様の充放電サイク
ルを行なった。その際の電池の規格化した放電容量とサ
イクル数の関係を図１に、符号１−５として示す。比較
例１に比べ、実施例１−５は、サイクル寿命が向上して
いることが明らかである。また、最大放電容量に達する
までのサイクル数が比較例１に比べ短く、電池使用初期
から良好な放電特性を有することが明かとなった。[Example 1-5] An AA battery similar to that of Comparative Example 1 was prepared, and the same pre-cycle as that of Comparative Example 1 was performed.
After storage at 1 ° C. for 1 day, the same charge / discharge cycle as in Comparative Example 1 was performed. The relationship between the normalized discharge capacity of the battery and the number of cycles in that case is shown as reference numeral 1-5 in FIG. It is apparent that the cycle life is improved in Examples 1-5 as compared with Comparative Example 1. Further, it was revealed that the number of cycles until the maximum discharge capacity was reached was shorter than that in Comparative Example 1, and that the battery had good discharge characteristics from the initial use of the battery.

【００２５】[0025]

【実施例１−６】比較例１と同様の単三型電池を作製し
比較例１と同様のプレサイクルを行なった後、室温で１
週間保管した後に比較例１と同様の充放電サイクルを行
なった。その際の電池の規格化した放電容量とサイクル
数の関係を図１に、符号１−６として示す。比較例１に
比べ、実施例１−６は、サイクル寿命が向上しているこ
とが明らかである。また、最大放電容量に達するまでの
サイクル数が比較例１に比べ短く、電池使用初期から良
好な放電特性を有することが明かとなった。[Examples 1-6] An AA battery similar to that of Comparative Example 1 was prepared, and a pre-cycle similar to that of Comparative Example 1 was performed.
After storage for a week, the same charge / discharge cycle as in Comparative Example 1 was performed. The relationship between the standardized discharge capacity of the battery and the number of cycles at that time is shown as reference numeral 1-6 in FIG. It is clear that the cycle life is improved in Examples 1-6 as compared with Comparative Example 1. Further, it was revealed that the number of cycles until the maximum discharge capacity was reached was shorter than that in Comparative Example 1, and that the battery had good discharge characteristics from the initial use of the battery.

【００２６】[0026]

【実施例１−７】比較例１と同様の単三型電池を作製
し、比較例１と同様のプレサイクルを行なった後、４５
℃で３日間保管した後に比較例１と同様の充放電サイク
ルを行なった。その際の電池の規格化した放電容量とサ
イクル数の関係を図２に、符号１−７として示す。比較
例１に比べ、実施例１−７は、サイクル寿命が向上して
いることが明らかである。また、最大放電容量に達する
までのサイクル数が比較例１に比べ短く、電池使用初期
から良好な放電特性を有することが明かとなった。[Example 1-7] An AA battery similar to that of Comparative Example 1 was prepared, and the same pre-cycle as that of Comparative Example 1 was performed.
After storage at 3 ° C. for 3 days, the same charge / discharge cycle as in Comparative Example 1 was performed. The relationship between the standardized discharge capacity of the battery and the number of cycles at that time is shown as reference numeral 1-7 in FIG. It is clear that the cycle life is improved in Examples 1-7 as compared with Comparative Example 1. Further, it was revealed that the number of cycles until reaching the maximum discharge capacity was shorter than that of Comparative Example 1, and that the battery had good discharge characteristics from the beginning of use of the battery.

【００２７】[0027]

【実施例２】比較例２と同様の単三型電池を作製し、比
較例４と同様のプレサイクルを行なった後、室温で１週
間保管した後に比較例２と同様に押し潰し試験を行なっ
た。その際の結果を表１に示す。押し潰しの際に、比較
例２に見られた電池正極蓋部分からの火花が認められ
ず、安全性が向上していることが明らかである。Example 2 An AA battery similar to that of Comparative Example 2 was prepared, subjected to the same pre-cycle as that of Comparative Example 4, stored at room temperature for 1 week, and then subjected to a crushing test as in Comparative Example 2. It was The results at that time are shown in Table 1. At the time of crushing, no spark was observed from the battery positive electrode lid portion seen in Comparative Example 2, and it is clear that safety is improved.

【００２８】[0028]

【実施例３】比較例３と同様の単三型電池を作製し比較
例３と同様のプレサイクルを行なった後、４５℃で３日
間保管した後に比較例３と同様に押し潰し試験を行なっ
た。その際の結果を表１に示す。押し潰しの際に、比較
例３に見られた電池正極蓋部分からの火花、発火が認め
られず、安全性が向上していることが明らかである。Example 3 An AA battery similar to that of Comparative Example 3 was prepared, subjected to the same pre-cycle as that of Comparative Example 3, stored at 45 ° C. for 3 days, and then subjected to a crushing test as in Comparative Example 3. It was The results at that time are shown in Table 1. At the time of crushing, no spark or ignition from the battery positive electrode lid portion observed in Comparative Example 3 was observed, and it is clear that the safety is improved.

【００２９】[0029]

【実施例４】比較例４と同様の単三型電池を作製し、比
較例４と同様のプレサイクルを行なった後、室温で１週
間保管した後に比較例４と同様に押し潰し試験を行なっ
た。その際の結果を表１に示す。押し潰しの際に、比較
例４に見られた電池正極蓋部分からの火花が認められ
ず、安全性が向上していることが明らかである。[Example 4] An AA battery similar to that of Comparative Example 4 was prepared, subjected to the same pre-cycle as that of Comparative Example 4, stored for one week at room temperature, and then subjected to a crushing test as in Comparative Example 4. It was The results at that time are shown in Table 1. At the time of crushing, no spark was observed from the battery positive electrode lid portion seen in Comparative Example 4, and it is clear that the safety is improved.

【００３０】[0030]

【実施例５】比較例５と同様の単三型電池を作製し、比
較例５と同様のプレサイクルを行なった後、室温で１週
間保管した後に比較例５と同様に押し潰し試験を行なっ
た。その際の結果を表１に示す。押し潰しの際に、比較
例５に見られた電池正極蓋部分からの火花が認められ
ず、安全性が向上していることが明らかである。Example 5 An AA battery similar to that of Comparative Example 5 was prepared, subjected to the same pre-cycle as Comparative Example 5, and then stored at room temperature for 1 week, and then subjected to a crushing test as in Comparative Example 5. It was The results at that time are shown in Table 1. At the time of crushing, no spark was observed from the battery positive electrode lid portion seen in Comparative Example 5, and it is clear that the safety is improved.

【００３１】 [0031]

【００３２】[0032]

【発明の効果】以上の説明から明らかなように、本発明
によればリチウム二次電池において、プレサイクル後の
電池を一定期間保管した後に、電池の使用を開始するこ
とで、電池使用初期から良好な放電特性を有し、充放電
寿命が長く、安全性が高いリチウム二次電池を実現でき
る。As is clear from the above description, according to the present invention, in the lithium secondary battery, after the pre-cycled battery is stored for a certain period of time, the battery is started to be used so that It is possible to realize a lithium secondary battery having good discharge characteristics, a long charge / discharge life, and high safety.

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

【図１】放電容量とサイクル数の関係を示した図。FIG. 1 is a diagram showing the relationship between discharge capacity and the number of cycles.

【図２】放電容量とサイクル数の関係を示した図。FIG. 2 is a diagram showing a relationship between discharge capacity and the number of cycles.

Claims (6)

【特許請求の範囲】[Claims] 【請求項１】負極としてリチウムあるいはリチウム合金
を活物質とし、リチウムイオンを挿入および脱離可能な
正極及び非水溶媒にイオン解離性のリチウム塩を溶解し
た電解液を有するリチウム二次電池において、電池使用
前に放電を少なくとも一回行ない、一定期間保管したこ
とを特徴とするリチウム二次電池。1. A lithium secondary battery comprising, as a negative electrode, lithium or a lithium alloy as an active material, a positive electrode into which lithium ions can be inserted and desorbed, and an electrolytic solution in which an ion dissociable lithium salt is dissolved in a non-aqueous solvent, A lithium secondary battery characterized in that it is discharged at least once before being used and stored for a certain period of time. 【請求項２】電池使用前の放電あるいは充放電を少なく
とも１回行なった電池を室温から４５℃の範囲で１日以
上保管したことを特徴とする請求項１記載のリチウム二
次電池。2. The lithium secondary battery according to claim 1, wherein the battery, which has been discharged or charged / discharged at least once before use, is stored at room temperature to 45 ° C. for 1 day or more. 【請求項３】電池使用善に放電あるいは充放電を少なく
とも１回行なった電池を室温で１週間以上あるいは４５
℃で３日以上保管したことを特徴とする請求項２記載の
リチウム二次電池。3. A battery that has been discharged or charged / discharged at least once for good battery use at room temperature for 1 week or more or 45
The lithium secondary battery according to claim 2, which is stored at 3 ° C for 3 days or more. 【請求項４】少なくともエチレンカーボネートを含む非
水溶媒にイオン解離性のリチウム塩を溶解した電解液を
有することを特徴とする請求項１から３記載のいずれか
のリチウム二次電池。4. The lithium secondary battery according to claim 1, further comprising an electrolytic solution in which an ion dissociative lithium salt is dissolved in a non-aqueous solvent containing at least ethylene carbonate. 【請求項５】前記非水溶媒にエステル類あるいはエーテ
ル類を含むことを特徴とする請求項４記載のリチウム二
次電池。5. The lithium secondary battery according to claim 4, wherein the non-aqueous solvent contains an ester or an ether. 【請求項６】前記エステル類がプロピレンカーボネート
または２−メチルテトラヒドロフランであり、前記エー
テル類がジメチルカーボネートであることを特徴とする
請求項５記載のリチウム二次電池。6. The lithium secondary battery according to claim 5, wherein the ester is propylene carbonate or 2-methyltetrahydrofuran and the ether is dimethyl carbonate.
JP6209096A 1994-08-10 1994-08-10 Lithium secondary battery Pending JPH0855636A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP6209096A JPH0855636A (en) 1994-08-10 1994-08-10 Lithium secondary battery

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6209096A JPH0855636A (en) 1994-08-10 1994-08-10 Lithium secondary battery

Publications (1)

Publication Number Publication Date
JPH0855636A true JPH0855636A (en) 1996-02-27

Family

ID=16567225

Family Applications (1)

Application Number Title Priority Date Filing Date
JP6209096A Pending JPH0855636A (en) 1994-08-10 1994-08-10 Lithium secondary battery

Country Status (1)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009170348A (en) * 2008-01-18 2009-07-30 Toyota Motor Corp Durability-improving method for lithium-ion secondary battery
JPWO2017043017A1 (en) * 2015-09-07 2018-06-21 パナソニックＩｐマネジメント株式会社 Nonaqueous electrolyte secondary battery
CN110622342A (en) * 2018-01-11 2019-12-27 株式会社Lg化学 Method for manufacturing lithium metal secondary battery including lithium electrode

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009170348A (en) * 2008-01-18 2009-07-30 Toyota Motor Corp Durability-improving method for lithium-ion secondary battery
JPWO2017043017A1 (en) * 2015-09-07 2018-06-21 パナソニックＩｐマネジメント株式会社 Nonaqueous electrolyte secondary battery
US11056723B2 (en) 2015-09-07 2021-07-06 Panasonic Intellectual Property Management Co., Ltd. Nonaqueous electrolyte secondary battery
CN110622342A (en) * 2018-01-11 2019-12-27 株式会社Lg化学 Method for manufacturing lithium metal secondary battery including lithium electrode
CN110622342B (en) * 2018-01-11 2022-11-18 株式会社Lg新能源 Method for manufacturing lithium metal secondary battery including lithium electrode
US11699793B2 (en) 2018-01-11 2023-07-11 Lg Energy Solution, Ltd. Method for fabrication of lithium metal secondary battery comprising lithium electrode

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