JPH05144473A - Secondary battery with nonaqueous electrolyte - Google Patents
Secondary battery with nonaqueous electrolyteInfo
- Publication number
- JPH05144473A JPH05144473A JP3308812A JP30881291A JPH05144473A JP H05144473 A JPH05144473 A JP H05144473A JP 3308812 A JP3308812 A JP 3308812A JP 30881291 A JP30881291 A JP 30881291A JP H05144473 A JPH05144473 A JP H05144473A
- Authority
- JP
- Japan
- Prior art keywords
- lithium
- negative electrode
- carbon material
- electrode plate
- positive electrode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
-
- 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
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、非水電解液二次電池、
特にリチウム二次電池の耐過放電特性の向上に関するも
のである。The present invention relates to a non-aqueous electrolyte secondary battery,
In particular, it relates to improvement of over-discharge resistance of a lithium secondary battery.
【０００２】近年、携帯電話、カムコーダなどのコード
レス情報・通信機器の目覚ましいポータブル化、インテ
リジェンス化に伴い、その駆動用電源として、小形軽量
で、高エネルギー密度の二次電池が求められている。非
水電解液二次電池、特にリチウム二次電池は次世代電池
の主力として大いに期待され、その潜在的な市場規模も
非常に大きい。[0002] In recent years, with the remarkable portability and intelligence of cordless information / communication devices such as mobile phones and camcorders, there has been a demand for a small, lightweight, high energy density secondary battery as a driving power source. Non-aqueous electrolyte secondary batteries, especially lithium secondary batteries, are highly expected as the mainstay of next-generation batteries, and their potential market size is also very large.
【０００３】[0003]
【従来の技術】従来、リチウム二次電池としては正極活
物質に遷移金属の酸化物、硫化物、例えば二酸化マンガ
ン（ＭｎＯ2）、二硫化モリブデン（ＭｏＳ2）などを、
負極活物質に金属リチウムをそれぞれ用いた電池系が提
案されていた。しかし、この電池では、充電時のリチウ
ムの析出形態が、非水電解液の組成、充電条件などの影
響を大きく受け、主として針状となり、これが負極から
脱落して、あるいはセパレータを貫通して正極と接触
し、内部短絡および発火の原因となるなど、安全性に問
題があるとされている。2. Description of the Related Art Conventionally, as a lithium secondary battery, a transition metal oxide or sulfide such as manganese dioxide (MnO 2 ) or molybdenum disulfide (MoS 2 ) is used as a positive electrode active material.
A battery system using metallic lithium as the negative electrode active material has been proposed. However, in this battery, the precipitation form of lithium during charging is greatly affected by the composition of the non-aqueous electrolyte, charging conditions, etc., and becomes mainly needle-shaped, which falls off from the negative electrode or penetrates the separator to form a positive electrode. It is said that there is a problem with safety such as contact with and causing internal short circuit and ignition.
【０００４】そこで、正負極に電気化学的にリチウムを
インターカレーション／ディインターカレーションする
化合物をそれぞれ用いた電池系が提案された。この電池
では、充電時にリチウムが析出することはなく、安全性
が期待できると同時に急速充電特性にも優れていると考
えられ、現在、研究開発が活発に行われている。Therefore, a battery system has been proposed in which a compound for electrochemically intercalating / deintercalating lithium is used for each of the positive and negative electrodes. It is considered that this battery does not deposit lithium during charging and that it can be expected to be safe and at the same time has excellent rapid charging characteristics, and thus research and development are currently being actively conducted.
【０００５】そして、この電池では、正極活物質として
は、遷移金属のリチウム含有複合酸化物、すなわち、層
状構造を有するＬｉＭＯ2あるいはスピネル構造を有す
るＬｉＭ2Ｏ4（Ｍは遷移金属、例えば、コバルト、マン
ガン、ニッケル、鉄）などが、高電圧、高エネルギー密
度を有するものとして注目されている。In this battery, as the positive electrode active material, a lithium-containing composite oxide of a transition metal, that is, LiMO 2 having a layered structure or LiM 2 O 4 having a spinel structure (M is a transition metal such as cobalt) is used. , Manganese, nickel, iron) and the like are attracting attention as having high voltage and high energy density.
【０００６】一方、負極活物質としては、層状構造を有
する炭素材が可逆的にリチウムをインターカレーション
／ディインターカレーションするものとして有望視され
ており、そのインターカレーション／ディインターカレ
ーションにおける可逆性と炭素材の物性、構造との関係
などについて検討が進められている。On the other hand, as a negative electrode active material, a carbon material having a layered structure is regarded as promising for reversibly intercalating / deintercalating lithium. In the intercalation / deintercalation, The relationship between reversibility, physical properties of carbon materials, and structure is being studied.
【０００７】[0007]
【発明が解決しようとする課題】以上のように、正極活
物質に遷移金属のリチウム含有複合酸化物を、負極活物
質に炭素材を用いることにより、小形軽量で、安全性に
も優れた高エネルギー密度の非水電解液二次電池を提供
できよう。As described above, by using a lithium-containing composite oxide of a transition metal as a positive electrode active material and a carbon material as a negative electrode active material, it is compact and lightweight, and is highly safe. An energy density non-aqueous electrolyte secondary battery can be provided.
【０００８】しかし、この電池にはまだいくつかの課題
が残されている。そのひとつとして、耐過放電特性の向
上が挙げられる。However, some problems still remain in this battery. One of them is improvement in over-discharge resistance.
【０００９】最近のコードレス情報・通信機器には、電
源電池の浪費をさけるためいわゆるオートパワーオフ機
能が搭載されている場合が多い。この機能はパワーオン
状態で、（１）機器は駆動はしていない、いわゆるポー
ズ状態で一定時間経過した場合、（２）機器は駆動して
おり、電池電圧が設定下限電圧に到達した場合、に自動
的にパワーオフ状態となるものである。In recent years, cordless information / communication devices are often equipped with a so-called auto power-off function in order to avoid wasting a power battery. This function is in the power-on state, (1) device is not driven, so-called pause state after a certain time has passed, (2) device is driven, when the battery voltage reaches the set lower limit voltage, The power is automatically turned off.
【００１０】このオートパワーオフ機能が作動した状態
のままでさらに放置された場合、電池は回路負荷により
放電し続け、やがて電池電圧が０Ｖに到達する。したが
って、このような過放電後においても再充電すれば容量
が回復する、いわゆる耐過放電特性に優れなければ電池
の実用性は非常に低いものとなる。When the auto power-off function is still in operation, the battery is continuously discharged by the circuit load, and eventually the battery voltage reaches 0V. Therefore, if the so-called over-discharge resistance characteristic, in which the capacity is restored by recharging even after such over-discharge, is not excellent, the practicality of the battery is extremely low.
【００１１】しかし、正極活物質に遷移金属のリチウム
含有複合酸化物を、負極活物質に炭素材をそれぞれ用い
た非水電解液二次電池の場合、このような過放電後に電
池を再充電しても容量がほとんど回復せず、しかも、サ
イクルに伴う容量劣化が過放電前と比較して非常に大き
くなることがわかった。However, in the case of a non-aqueous electrolyte secondary battery in which a lithium-containing composite oxide of a transition metal is used as the positive electrode active material and a carbon material is used as the negative electrode active material, the battery is recharged after such overdischarge. However, it was found that the capacity was hardly recovered and that the deterioration of capacity with the cycle was much larger than that before the overdischarge.
【００１２】負極活物質に炭素材を用いる場合、負極の
電位、すなわち炭素材がリチウムをインターカレーショ
ン／ディインターカレーションする電位は、炭素材の物
性、特に層状構造の発達の度合い（層間距離、ｃ軸方向
の層の重なり、ａ軸方向の層の広がり）により異なる
が、リチウムに対して約１．５Ｖ以下である。When a carbon material is used as the negative electrode active material, the potential of the negative electrode, that is, the potential at which the carbon material intercalates / deintercalates lithium depends on the physical properties of the carbon material, particularly the degree of development of the layered structure (interlayer distance). , The layer overlaps in the c-axis direction and the layer spread in the a-axis direction), but is about 1.5 V or less with respect to lithium.
【００１３】しかし、この電池を過放電した場合、負極
の電位がリチウムに対して約３．２Ｖ以上にまで上昇し
て正極の電位と等しくなり、電池電圧が０Ｖに到達して
いることがわかった。However, when this battery was over-discharged, it was found that the potential of the negative electrode rose to about 3.2 V or more with respect to lithium and became equal to the potential of the positive electrode, and the battery voltage reached 0 V. It was
【００１４】このため、炭素材の物性および構造が変化
して、リチウムのインターカレーション／ディインター
カレーションにおける可逆性が失われ、それが過放電後
に電池を再充電しても容量がほとんど回復せず、サイク
ルに伴う容量劣化が過放電前と比較して非常に大きくな
る原因であると考えられる。For this reason, the physical properties and structure of the carbon material are changed, and reversibility in lithium intercalation / deintercalation is lost, and even if the battery is recharged after overdischarge, the capacity is almost recovered. Without this, it is considered that the capacity deterioration due to the cycle becomes much larger than that before the overdischarge.
【００１５】本発明は、この課題を解決するものであ
り、リチウム二次電池の耐過放電特性の向上を目的とす
るものである。The present invention solves this problem, and an object thereof is to improve the over-discharge resistance of a lithium secondary battery.
【００１６】[0016]
【課題を解決するための手段】本発明は、正極に遷移金
属のリチウム含有複合酸化物を、負極に炭素材をそれぞ
れ用い、正極板および負極板をセパレータとともに渦巻
状に巻回した非水電解液二次電池において、負極板の最
外周に相当する部分で、なおかつ正極板と対向しない部
分に金属リチウム箔を貼付し、電位差あるいは濃度差に
よりリチウムを炭素材中に拡散させ、負極の炭素材に放
電可能なリチウムを保持させたものである。Means for Solving the Problems The present invention is a nonaqueous electrolysis in which a positive electrode plate and a negative electrode plate are spirally wound together with a separator using a lithium-containing composite oxide of a transition metal for a positive electrode and a carbon material for a negative electrode, respectively. In the liquid secondary battery, a metal lithium foil is attached to a portion corresponding to the outermost periphery of the negative electrode plate and not facing the positive electrode plate, and lithium is diffused into the carbon material due to the potential difference or the concentration difference, and the negative electrode carbon material is used. It holds lithium that can be discharged.
【００１７】さらにここでのリチウム箔の貼付容量は、
負極に用いる炭素材の飽和可逆容量に対して４〜４０％
としたものである。Furthermore, the sticking capacity of the lithium foil here is
4-40% of the saturated reversible capacity of the carbon material used for the negative electrode
It is what
【００１８】ここで、負極に用いる炭素材の飽和可逆容
量は以下の手法により算出した。正極活物質に炭素材
を、負極活物質に金属リチウムをそれぞれ用いて、２０
℃で電流密度０．５ｍＡ／cm2の定電流充放電を５サイ
クル繰り返した。このときの容量を飽和可逆容量とし
た。なお、充電時の上限電圧は１．０Ｖ、放電時の下限
電圧は０Ｖとした。The saturation reversible capacity of the carbon material used for the negative electrode was calculated by the following method. A carbon material is used for the positive electrode active material and metallic lithium is used for the negative electrode active material.
Constant-current charging / discharging with a current density of 0.5 mA / cm 2 at 5 ° C. was repeated 5 cycles. The capacity at this time was defined as the saturated reversible capacity. The upper limit voltage during charging was 1.0V and the lower limit voltage during discharging was 0V.
【００１９】加えて正極活物質には、ＬｉＭＯ2あるい
はＬｉＭ2Ｏ4（但しＭはコバルト、マンガン、ニッケ
ル、鉄のいずれか）を、単独かあるいはコバルト、マン
ガン、ニッケル、鉄の一部を他の遷移金属で置換したリ
チウム含有複合酸化物を、負極には、粉末Ｘ線回折法に
よる格子面間隔（ｄ002）が０．３４２ｎｍ以下の炭素
材が好ましい。In addition, as the positive electrode active material, LiMO 2 or LiM 2 O 4 (where M is cobalt, manganese, nickel or iron) is used alone or a part of cobalt, manganese, nickel or iron is used. For the negative electrode of the lithium-containing composite oxide substituted with the transition metal, the carbon material having a lattice plane spacing (d 002 ) by powder X-ray diffraction method of 0.342 nm or less is preferable.
【００２０】[0020]
【作用】本発明の、正極板および負極板をセパレータと
ともに渦巻状に巻回した非水電解液二次電池では、負極
の最外周に相当する部分で、なおかつ正極板と対向しな
い部分に貼付した金属リチウム箔は、非水電解液の存在
下で、炭素材との間に局部電池を構成し、電気化学的に
金属リチウムが溶解して近傍の炭素材中に順次インター
カレーションされ、炭素材に放電可能なリチウムとして
保持される。In the non-aqueous electrolyte secondary battery of the present invention in which the positive electrode plate and the negative electrode plate are spirally wound together with the separator, the non-aqueous electrolyte secondary battery is attached to a portion corresponding to the outermost periphery of the negative electrode and not facing the positive electrode plate. The metallic lithium foil forms a local battery between the metallic lithium foil and the carbon material in the presence of the non-aqueous electrolyte, and the metallic lithium is electrochemically dissolved and sequentially intercalated into the neighboring carbon material. Retained as lithium that can be discharged.
【００２１】この炭素材に保持されたリチウムが、過放
電時に放電することにより負極の電位が上昇することは
ない。このため、炭素材の物性および構造が変化せず、
リチウムのインターカレーション／ディインターカレー
ションにおける可逆性が失われない。したがって過放電
後の電池であっても、再充電によって容量が速やかに回
復し、サイクルに伴う容量劣化が過放電前と比較して変
化しなく、耐過放電特性を向上させることができる。The lithium held on the carbon material does not rise in potential of the negative electrode due to discharge during overdischarge. Therefore, the physical properties and structure of the carbon material do not change,
Reversibility in lithium intercalation / deintercalation is not lost. Therefore, even in a battery after over-discharging, the capacity is quickly restored by recharging, the capacity deterioration due to the cycle does not change as compared with that before over-discharging, and the over-discharge resistance characteristic can be improved.
【００２２】[0022]
【実施例】以下、本発明の一実施例について図面を参照
しながら説明する。本発明の円筒形リチウム二次電池の
構成縦断面図を図１に示す。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a vertical cross-sectional view of the configuration of the cylindrical lithium secondary battery of the present invention.
【００２３】正極板１は、炭酸リチウム（ＬｉＣＯ3）
と四酸化三コバルト（Ｃｏ3Ｏ4）を混合して空気中にお
いて９００℃で焼成したコバルト酸リチウム（ＬｉＣｏ
Ｏ2）を活物質とし、これに導電剤としてアセチレンブ
ラックを３重量％混合した後、結着剤としてポリ四フッ
化エチレン樹脂の水性ディスパージョンを７重量％練合
してペースト状とした合剤を、アルミニウム箔からなる
芯材の両面に塗着、乾燥し圧延したものである。またそ
の端部に正極リード板４をスポット溶接している。正極
板の寸法は、幅４０mm、長さ２５０mm、厚さは０．１７
０mmである。The positive electrode plate 1 is made of lithium carbonate (LiCO 3 )
And tricobalt tetraoxide (Co 3 O 4 ) were mixed and fired at 900 ° C. in air lithium cobalt oxide (LiCo
O 2 ) as an active material, 3% by weight of acetylene black as a conductive agent was mixed therein, and then 7% by weight of an aqueous dispersion of polytetrafluoroethylene resin was kneaded as a binder to form a paste. The agent is applied on both sides of a core material made of aluminum foil, dried and rolled. Further, the positive electrode lead plate 4 is spot-welded to the end portion thereof. The size of the positive electrode plate is 40 mm in width, 250 mm in length, and 0.17 in thickness.
It is 0 mm.
【００２４】また負極板２は、メソフェーズピッチをア
ルゴン雰囲気下において２８００℃で熱処理した球状黒
鉛を活物質とし、結着剤としてポリ四フッ化エチレン樹
脂の水性ディスパージョンを５重量％練合してペースト
状とした合剤２ａを、銅箔からなる芯材２ｂの両面に塗
着、乾燥し圧延したものである。またその端部に負極リ
ード板５をスポット溶接している。負極板の寸法は、幅
４２mm、長さ２７０mm、厚さは０．２０５mmである。The negative electrode plate 2 was prepared by kneading mesophase pitch in an argon atmosphere at 2800 ° C. with spherical graphite as an active material and kneading 5% by weight of an aqueous dispersion of polytetrafluoroethylene resin as a binder. The mixture 2a in the form of paste is applied to both surfaces of a core material 2b made of copper foil, dried and rolled. Further, the negative electrode lead plate 5 is spot-welded to the end portion thereof. The negative electrode plate has a width of 42 mm, a length of 270 mm, and a thickness of 0.205 mm.
【００２５】ここで、物性、構造の異なる種々の炭素材
について予備検討を進めたところ、粉末Ｘ線回折法によ
る格子面間隔（ｄ002）が、０．３４２ｎｍ以下の炭素
材が高容量であり、可逆性にも優れることがわかった。
ちなみに、メソフェーズピッチをアルゴン雰囲気下にお
いて２８００℃で熱処理した球状黒鉛は、粉末Ｘ線回折
法による格子面間隔（ｄ002）が、０．３４２ｎｍ以下
である。As a result of preliminary examination of various carbon materials having different physical properties and structures, a carbon material having a lattice spacing (d 002 ) by powder X-ray diffraction method of 0.342 nm or less has a high capacity. It was also found to be excellent in reversibility.
By the way, the spheroidal graphite obtained by heat-treating mesophase pitch at 2800 ° C. in an argon atmosphere has a lattice spacing (d 002 ) according to a powder X-ray diffraction method of 0.342 nm or less.
【００２６】セパレータ３はポリプロピレンからなる多
孔性フィルムを、正極板および負極板よりも幅広く裁断
して用いた。As the separator 3, a porous film made of polypropylene was used after being cut wider than the positive electrode plate and the negative electrode plate.
【００２７】正極板および負極板は、セパレータととも
に全体を渦巻状に巻回して極板群を構成した。The positive electrode plate and the negative electrode plate were spirally wound together with the separator to form an electrode plate group.
【００２８】次に上記極板群の上下部を温風で加熱し、
セパレータ３を熱収縮させた。そして極板群の下側に下
部絶縁リング６を装着し、電池ケース７に収容して負極
リード板５を電池ケース７にスポット溶接した。また極
板群の上側には上部絶縁リング８を装着し、電池ケース
７の上部に溝入れした後、非水電解液を注入した。非水
電解液は、エチレンカーボネート（ＥＣ）およびジエチ
レンカーボネート（ＤＥＣ）を体積比で１：１に混合
し、六フッ化リン酸リチウム（ＬｉＰＦ6）を１モル／
１溶解させたものを用いた。あらかじめガスケットが組
み込まれた組立封口板９と正極リード板４をスポット溶
接した後、組立封口板９を電池ケース７に装着し、カシ
メ封口して電池を構成した。この電池の寸法は、外径１
４mm、総高５０mm（単３形）である。Next, the upper and lower parts of the electrode plate group are heated with warm air,
The separator 3 was heat shrunk. Then, the lower insulating ring 6 was attached to the lower side of the electrode plate group, housed in the battery case 7, and the negative electrode lead plate 5 was spot-welded to the battery case 7. Further, an upper insulating ring 8 was attached to the upper side of the electrode plate group, a groove was formed in the upper portion of the battery case 7, and then a nonaqueous electrolytic solution was injected. The non-aqueous electrolytic solution was prepared by mixing ethylene carbonate (EC) and diethylene carbonate (DEC) at a volume ratio of 1: 1 and adding lithium hexafluorophosphate (LiPF 6 ) at 1 mol / mol.
One that was dissolved was used. After the assembly sealing plate 9 in which a gasket was incorporated in advance and the positive electrode lead plate 4 were spot-welded, the assembly sealing plate 9 was mounted on the battery case 7 and caulked and sealed to form a battery. This battery has an outer diameter of 1
It is 4 mm and the total height is 50 mm (AA size).
【００２９】評価試験 構成した電池の耐過放電特性は以下の試験方法で評価し
た。まず、２０℃で１００ｍＡの定電流充放電を５０サ
イクル繰り返した。なお、充電時の上限電圧は４．１
Ｖ、放電時の下限電圧は３．０Ｖとした。その後、電池
を放電状態から、過放電状態としてさらに１ｋΩの定抵
抗放電を２週間継続した。このとき、参照極として金属
リチウムを用いて正、負極の過放電挙動を観察した結果
を図２に示した。そして、再び１００ｍＡの定電流充放
電を５０サイクル繰り返した。ここでの容量回復特性お
よび過放電前後でのサイクル特性を比較した結果を図３
に示した。Evaluation Test The overdischarge resistance of the constructed battery was evaluated by the following test method. First, 100 mA constant current charge / discharge at 20 ° C. was repeated 50 cycles. The upper limit voltage during charging is 4.1.
V, the lower limit voltage during discharge was 3.0V. Then, the battery was changed from the discharged state to the over-discharged state, and the constant resistance discharge of 1 kΩ was further continued for 2 weeks. At this time, the results of observing the overdischarge behavior of the positive and negative electrodes using metallic lithium as the reference electrode are shown in FIG. Then, the constant current charge / discharge of 100 mA was repeated again for 50 cycles. Fig. 3 shows the results of comparison between the capacity recovery characteristics and the cycle characteristics before and after over-discharge.
It was shown to.
【００３０】図３から明らかなように、過放電後、電池
は充電しても容量は約５５％しか回復せず、しかもサイ
クルに伴う容量劣化が過放電前と比較して著しく大きい
ことがわかった。As is apparent from FIG. 3, after over-discharging, the battery recovers only about 55% of its capacity even after charging, and the capacity deterioration due to cycling is significantly larger than that before over-discharging. It was
【００３１】また図２に示すように、負極の電位が過放
電時にリチウムに対して３．２Ｖ以上にまで上昇して正
極の電位と等しくなり、電池電圧が０Ｖに到達している
ことがわかった。Further, as shown in FIG. 2, it was found that the potential of the negative electrode increased to 3.2 V or more with respect to lithium during over-discharging and became equal to the potential of the positive electrode, and the battery voltage reached 0 V. It was
【００３２】通常の充放電において、正極の電位はこの
付近であり問題はないと考えられるが、負極の電位は約
０．１Ｖ（充電時）In normal charging / discharging, the potential of the positive electrode is in the vicinity of this and there is no problem, but the potential of the negative electrode is about 0.1 V (during charging).
【００３３】[0033]
【外１】 [Outer 1]
【００３４】約０．５Ｖ（放電時）である。このため、
炭素材の物性および構造が変化して、リチウムのインタ
ーカレーション／ディインターカレーションにおける可
逆性が失われ、その結果、過放電後の電池は、再充電し
ても容量がほとんど回復せず、サイクルに伴う容量劣化
が過放電前と比較して非常に大きくなると考えられる。It is about 0.5 V (during discharge). For this reason,
The physical properties and structure of the carbon material are changed, and the reversibility of lithium intercalation / deintercalation is lost. As a result, the battery after over-discharging hardly recovers its capacity even when recharged. It is considered that the capacity deterioration due to the cycle becomes much larger than that before the overdischarge.
【００３５】実施例１ 負極板の最外周に相当する部分で、なおかつ正極板と対
向してしない部分にあらかじめ金属リチウム箔１０を貼
付した負極板を用いて前記の場合と同様に電池を構成
し、金属リチウムを負極の炭素材中に拡散させた電池の
耐過放電特性を評価した。この電池の負極板の構成を図
４（ａ），（ｂ）に示した。負極板の最外周に相当する
部分であり、なおかつ正極板と対向していない部分は幅
４２mm、長さ４５mmである。一例として金属リチウムの
貼付容量を炭素材の飽和可逆容量に対して２０％とした
場合の正負極の過放電挙動を観察した結果を図５に示し
た。このとき、金属リチウム箔の寸法は幅３０mm、長さ
２０mm、厚さは０．０８０mmとした。Example 1 A battery was constructed in the same manner as in the above case by using a negative electrode plate in which a metallic lithium foil 10 was previously attached to a portion corresponding to the outermost periphery of the negative electrode plate and not facing the positive electrode plate. The over-discharge resistance characteristics of the battery in which metallic lithium was diffused in the carbon material of the negative electrode were evaluated. The structure of the negative electrode plate of this battery is shown in FIGS. 4 (a) and 4 (b). The portion corresponding to the outermost periphery of the negative electrode plate and not facing the positive electrode plate has a width of 42 mm and a length of 45 mm. As an example, the results of observing the overdischarge behavior of the positive and negative electrodes when the attachment capacity of metallic lithium was 20% of the saturated reversible capacity of the carbon material were shown in FIG. At this time, the dimensions of the metallic lithium foil were 30 mm in width, 20 mm in length, and 0.080 mm in thickness.
【００３６】また、金属リチウム箔の貼付容量と耐過放
電特性として容量回復特性との関係を図６に示した。こ
のときの金属リチウム箔の寸法は幅３０mm、長さ２０mm
で固定し、厚さで容量を調整した。FIG. 6 shows the relationship between the sticking capacity of the metallic lithium foil and the capacity recovery characteristic as the over-discharge resistance characteristic. The dimensions of the metallic lithium foil at this time are 30 mm in width and 20 mm in length.
It was fixed with and the volume was adjusted by the thickness.
【００３７】図６から明らかなように、金属リチウムの
貼付容量を炭素材の飽和可逆容量に対して４％以上とす
れば従来例と比較して良好な耐過放電特性が得られるこ
とがわかった。As is clear from FIG. 6, when the metal lithium sticking capacity is 4% or more of the saturated reversible capacity of the carbon material, better over-discharge resistance characteristics can be obtained as compared with the conventional example. It was
【００３８】また、図５に示すように、負極の電位が過
放電時にリチウムに対して１．５Ｖ前後までしか上昇し
ないことがわかった。さらに、金属リチウム箔の貼付容
量を炭素材の飽和可逆容量に対して４％以上とすれば同
様の過放電挙動となることを確認した。Further, as shown in FIG. 5, it was found that the potential of the negative electrode increased only to about 1.5 V with respect to lithium during overdischarge. Further, it was confirmed that similar over-discharge behavior was obtained when the attachment capacity of the metallic lithium foil was 4% or more with respect to the saturated reversible capacity of the carbon material.
【００３９】これは、正極板および負極板をセパレータ
とともに渦巻状に巻回して構成した非水電解液二次電池
において、負極板の最外周に相当する部分で、なおかつ
正極板と対向しない部分に貼付した金属リチウム箔は、
非水電解液の存在下で、炭素材との間で局部電池を構成
し、電気化学的に金属リチウムが溶解して近傍の炭素材
中へ順次インターカレーションされ、放電可能なリチウ
ムとして炭素材に保持されており、これが過放電時に放
電したためであると考えられる。This is a non-aqueous electrolyte secondary battery formed by spirally winding a positive electrode plate and a negative electrode plate together with a separator, at a portion corresponding to the outermost periphery of the negative electrode plate and not facing the positive electrode plate. The metallic lithium foil attached is
In the presence of the non-aqueous electrolyte, a local battery is formed between the carbon material and the carbon material, and the lithium metal is electrochemically dissolved and sequentially intercalated into the nearby carbon material, and the carbon material is discharged as lithium. It is considered that this is due to discharge during overdischarge.
【００４０】このため、炭素材の物性および構造が変化
せず、リチウムのインターカレーション／ディインター
カレーションにおける可逆性が失われない。したがって
過放電後の電池であっても、再充電によって容量が速や
かに回復し、サイクルに伴う容量劣化が過放電前と比較
して変化しない。すなわち、良好な耐過放電特性が得ら
れたと考えられる。Therefore, the physical properties and structure of the carbon material do not change, and reversibility in lithium intercalation / deintercalation is not lost. Therefore, even in the case of a battery after over-discharging, the capacity is promptly restored by recharging, and the capacity deterioration due to the cycle does not change as compared with that before over-discharging. That is, it is considered that good over-discharge resistance characteristics were obtained.
【００４１】ここで、金属リチウム箔の貼付容量を炭素
材の飽和可逆容量に対して４％以上とした場合には容量
回復特性が良好であった。しかし、さらに、４０％以上
とその量を多くした場合には容量回復特性が劣化し始め
る。これは、金属リチウム箔の貼付容量が増加すると、
正極の電位が過放電時にリチウムに対して１．５Ｖ以下
にまで下降してから負極の電位と等しくなり、電池電圧
が０Ｖに到達するまでの容量が増加することから、コバ
ルト酸リチウム（ＬｉＣｏＯ2）の物性および構造が変
化して、リチウムのインターカレーション／ディインタ
ーカレーションにおける可逆性が失われたためであると
考えられる。Here, when the attachment capacity of the metallic lithium foil was 4% or more of the saturated reversible capacity of the carbon material, the capacity recovery characteristics were good. However, when the amount is further increased to 40% or more, the capacity recovery characteristic starts to deteriorate. This is because when the attachment capacity of metallic lithium foil increases,
Since the potential of the positive electrode drops to 1.5 V or less with respect to lithium during over-discharging and becomes equal to the potential of the negative electrode, and the capacity increases until the battery voltage reaches 0 V, lithium cobalt oxide (LiCoO 2 It is considered that the reversibility of lithium intercalation / deintercalation is lost due to changes in the physical properties and structure of).
【００４２】一方、負極板の最外周に相当する部分以外
の、正極板と対向している部分にあらかじめ金属リチウ
ム箔を貼付した負極板を用いて、従来例の場合と同様に
電池を構成し耐過放電特性を評価したところ同様の効果
が得られたが、容量が低下した。その度合いは金属リチ
ウム箔の貼付面積に比例することから、金属リチウム箔
を貼付した部分では通常の充放電反応が疎外されると考
えられる。すなわち、実用性が低いものとなる。On the other hand, a battery is constructed in the same manner as in the conventional example by using a negative electrode plate in which a metallic lithium foil is attached in advance to a portion facing the positive electrode plate other than the portion corresponding to the outermost periphery of the negative electrode plate. When the over-discharge resistance property was evaluated, the same effect was obtained, but the capacity decreased. Since the degree is proportional to the attachment area of the metal lithium foil, it is considered that the normal charge / discharge reaction is alienated at the portion where the metal lithium foil is attached. That is, the practicability is low.
【００４３】したがって、正極板および負極板をセパレ
ータとともに渦巻状に巻回して構成した非水電解液二次
電池において、負極板の最外周に相当する部分で、なお
かつ正極板と対向しない部分にリチウム箔を貼付するこ
とで負極の炭素材中に放電可能なリチウムを保持させ、
その貼付容量は、負極に用いる炭素材の飽和可逆容量に
対して４〜４０％とするのが好ましい。Therefore, in the non-aqueous electrolyte secondary battery formed by spirally winding the positive electrode plate and the negative electrode plate together with the separator, lithium is provided in a portion corresponding to the outermost periphery of the negative electrode plate and not facing the positive electrode plate. By attaching a foil, hold the dischargeable lithium in the carbon material of the negative electrode,
The application capacity is preferably 4 to 40% of the saturated reversible capacity of the carbon material used for the negative electrode.
【００４４】なお、本実施例では、正極活物質にコバル
ト酸リチウム（ＬｉＣｏＯ2）を用いたが、ＬｉＭＯ2あ
るいはＬｉＭ2Ｏ4（但しＭはコバルト、マンガン、ニッ
ケル、鉄のいずれか）を、単独かあるいはコバルト、マ
ンガン、ニッケル、鉄の一部を他の遷移金属で置換した
リチウム含有複合酸化物を用いた場合もほぼ同様の効果
が得られた。Although lithium cobalt oxide (LiCoO 2 ) was used as the positive electrode active material in this embodiment, LiMO 2 or LiM 2 O 4 (where M is cobalt, manganese, nickel or iron) is used. Almost the same effect was obtained when a single or a lithium-containing composite oxide in which a part of cobalt, manganese, nickel and iron was replaced with another transition metal was used.
【００４５】また本実施例では、非水電解液の溶質に六
フッ化リン酸リチウム（ＬｉＰＦ6）を用いたが、他の
リチウム塩、例えば、過塩素酸リチウム（ＬｉＣＩ
Ｏ4）、六フッ化砒酸リチウム（ＬｉＡｓＦ6）、ホウフ
ッ化リチウム（ＬｉＢＦ4）などを用いた場合も同様の
効果が得られた。In this embodiment, lithium hexafluorophosphate (LiPF 6 ) is used as the solute of the non-aqueous electrolyte, but other lithium salts such as lithium perchlorate (LiCI) are used.
Similar effects were obtained when O 4 ), lithium hexafluoroarsenate (LiAsF 6 ), lithium borofluoride (LiBF 4 ) and the like were used.
【００４６】さらに本実施例では、非水電解液の溶媒に
エチレンカーボネート（ＥＣ）およびジエチレンカーボ
ネート（ＤＥＣ）を混合して用いたが、プロピレンカー
ボネート（ＰＣ）、ブチレンカーボネート（ＢＣ）など
のエステル類、テトラヒドロフラン（ＴＨＦ）などのエ
ーテル類などを、単独あるいはこれら両者を混合して用
いた場合も同様の効果が得られた。Further, in this embodiment, ethylene carbonate (EC) and diethylene carbonate (DEC) were mixed and used in the solvent of the non-aqueous electrolyte, but esters such as propylene carbonate (PC) and butylene carbonate (BC) were used. Similar effects were also obtained when ethers such as tetrahydrofuran (THF) were used alone or in combination of both.
【００４７】[0047]
【発明の効果】以上のように本発明によれば、正極に遷
移金属のリチウム含有複合酸化物を、負極に炭素材をそ
れぞれ用い、正極板および負極板をセパレータとともに
渦巻状に巻回した非水電解液二次電池において、負極板
の最外周に相当する部分で、なおかつ正極板と対向して
いない部分に金属リチウム箔を貼付し、これを負極の炭
素材中に拡散保持させて放電可能なリチウムをもたせる
ことにより、耐過放電特性を著しく向上させることがで
きる。As described above, according to the present invention, a lithium-containing composite oxide of a transition metal is used for the positive electrode and a carbon material is used for the negative electrode, and the positive electrode plate and the negative electrode plate are spirally wound together with the separator. In a water electrolyte secondary battery, a metallic lithium foil is attached to the portion corresponding to the outermost periphery of the negative electrode plate and not facing the positive electrode plate, and this can be held by diffusion in the carbon material of the negative electrode and discharged. By providing such lithium, the over-discharge resistance characteristic can be remarkably improved.
【図１】本発明の円筒形リチウム二次電池の構成を示す
縦断面図FIG. 1 is a vertical cross-sectional view showing the structure of a cylindrical lithium secondary battery of the present invention.
【図２】これまでの電池の正、負極の過放電挙動を示す
図FIG. 2 is a view showing the overdischarge behavior of positive and negative electrodes of a conventional battery.
【図３】これまでの電池の耐過放電特性を示す図FIG. 3 is a diagram showing the over-discharge resistance characteristics of conventional batteries.
【図４】（ａ）本発明の実施例１の負極板の構成を示す
平面図 （ｂ）同じく側面図FIG. 4 (a) is a plan view showing the configuration of the negative electrode plate according to the first embodiment of the present invention. FIG.
【図５】本発明の正、負極の過放電挙動を示す図FIG. 5 is a diagram showing overdischarge behavior of positive and negative electrodes of the present invention.
【図６】本発明の金属リチウムの貼付容量と耐過放電特
性との関係を示す図FIG. 6 is a diagram showing the relationship between the sticking capacity of the metallic lithium of the present invention and the over-discharge resistance.
１ 正極板 ２ 負極板 ２ａ 負極合剤 ２ｂ 負極芯材 ３ セパレータ ４ 正極リード板 ５ 負極リード板 ６ 下部絶縁リング ７ 電池ケース ８ 上部絶縁板 ９ 組立封口板 １０ 金属リチウム DESCRIPTION OF SYMBOLS 1 Positive electrode plate 2 Negative electrode plate 2a Negative electrode mixture 2b Negative electrode core material 3 Separator 4 Positive electrode lead plate 5 Negative electrode lead plate 6 Lower insulating ring 7 Battery case 8 Upper insulating plate 9 Assembly sealing plate 10 Metallic lithium
Claims (4)
を、負極に炭素材をそれぞれ用い、正極板、負極板をセ
パレータとともに渦巻状に巻回した非水電解液二次電池
であり、負極板の最外周に相当する部分で、なおかつ正
極板と対向しない部分に金属リチウム箔を貼付し、電位
差あるいは濃度差により前記リチウムを炭素材中に拡散
させたことを特徴とする非水電解液二次電池。1. A non-aqueous electrolyte secondary battery in which a lithium-containing composite oxide of a transition metal is used for a positive electrode and a carbon material is used for a negative electrode, and a positive electrode plate and a negative electrode plate are spirally wound together with a separator. A non-aqueous electrolyte solution characterized in that a metal lithium foil is attached to a portion corresponding to the outermost periphery of the plate and not facing the positive electrode plate, and the lithium is diffused in the carbon material due to a potential difference or a concentration difference. Next battery.
る炭素材の飽和可逆容量に対して４〜４０％である請求
項１記載の非水電解液二次電池。2. The non-aqueous electrolyte secondary battery according to claim 1, wherein the sticking capacity of the metallic lithium foil is 4 to 40% of the saturated reversible capacity of the carbon material used for the negative electrode.
子面間隔（ｄ002）が０．３４２ｎｍ以下である請求項
１記載の非水電解液二次電池。3. The non-aqueous electrolyte secondary battery according to claim 1, wherein the carbonaceous material of the negative electrode has a lattice spacing (d 002 ) determined by a powder X-ray diffraction method of 0.342 nm or less.
はＬｉＭ2Ｏ4（但しＭはコバルト、マンガン、ニッケ
ル、鉄のいずれか）を、単独かあるいはコバルト、マン
ガン、ニッケル、鉄の一部を他の遷移金属で置換したリ
チウム含有複合酸化物である請求項１記載の非水電解液
二次電池。4. The positive electrode active material is one of the general formulas LiMO 2 or LiM 2 O 4 (where M is cobalt, manganese, nickel or iron), alone or in part of cobalt, manganese, nickel or iron. The non-aqueous electrolyte secondary battery according to claim 1, which is a lithium-containing composite oxide in which is replaced with another transition metal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3308812A JP3030996B2 (en) | 1991-11-25 | 1991-11-25 | Non-aqueous electrolyte secondary battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3308812A JP3030996B2 (en) | 1991-11-25 | 1991-11-25 | Non-aqueous electrolyte secondary battery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05144473A true JPH05144473A (en) | 1993-06-11 |
| JP3030996B2 JP3030996B2 (en) | 2000-04-10 |
Family
ID=17985612
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3308812A Expired - Lifetime JP3030996B2 (en) | 1991-11-25 | 1991-11-25 | Non-aqueous electrolyte secondary battery |
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| Country | Link |
|---|---|
| JP (1) | JP3030996B2 (en) |
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| WO1996027910A1 (en) * | 1995-03-06 | 1996-09-12 | Fuji Photo Film Co., Ltd. | Nonaqueous secondary cell |
| EP0964468A1 (en) * | 1997-01-27 | 1999-12-15 | Kanebo Ltd. | Organic electrolytic battery |
| WO2000007255A1 (en) * | 1998-07-27 | 2000-02-10 | Kanebo, Limited | Organic electrolytic cell |
| JP2007500922A (en) * | 2003-07-29 | 2007-01-18 | エフエムシー・コーポレイション | Dispersion of lithium metal at the electrode. |
| JP2007305596A (en) * | 1995-03-06 | 2007-11-22 | Ube Ind Ltd | Nonaqueous secondary battery |
| JP2009123374A (en) * | 2007-11-12 | 2009-06-04 | Fdk Corp | Nonaqueous electrolyte power storage device |
| JP2009170384A (en) * | 2008-01-21 | 2009-07-30 | Nec Tokin Corp | Lithium secondary battery |
| US7682739B2 (en) | 2004-05-12 | 2010-03-23 | Mitsui Mining & Smelting Co., Ltd. | Negative electrode for nonaqueous secondary battery and process of producing the same |
| WO2012105052A1 (en) * | 2011-02-04 | 2012-08-09 | トヨタ自動車株式会社 | Secondary battery |
| JP2013206544A (en) * | 2012-03-27 | 2013-10-07 | Panasonic Corp | Cylindrical lithium ion secondary battery |
| CN104752773A (en) * | 2015-04-01 | 2015-07-01 | 广东烛光新能源科技有限公司 | Preparation method of lithium ion battery |
| WO2018216585A1 (en) * | 2017-05-25 | 2018-11-29 | 株式会社村田製作所 | Non-aqueous electrolyte secondary battery and method for producing non-aqueous electrolyte secondary battery |
-
1991
- 1991-11-25 JP JP3308812A patent/JP3030996B2/en not_active Expired - Lifetime
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| EP0817294A1 (en) * | 1995-03-06 | 1998-01-07 | Fuji Photo Film Co., Ltd. | Nonaqueous secondary cell |
| EP0817294A4 (en) * | 1995-03-06 | 2004-07-28 | Ube Industries | Nonaqueous secondary cell |
| EP1679756A1 (en) * | 1995-03-06 | 2006-07-12 | Ube Industries, Ltd. | Nonaqueous secondary lithium battery |
| JP2007305596A (en) * | 1995-03-06 | 2007-11-22 | Ube Ind Ltd | Nonaqueous secondary battery |
| WO1996027910A1 (en) * | 1995-03-06 | 1996-09-12 | Fuji Photo Film Co., Ltd. | Nonaqueous secondary cell |
| EP0964468A1 (en) * | 1997-01-27 | 1999-12-15 | Kanebo Ltd. | Organic electrolytic battery |
| EP0964468A4 (en) * | 1997-01-27 | 2004-09-29 | Kanebo Ltd | Organic electrolytic battery |
| WO2000007255A1 (en) * | 1998-07-27 | 2000-02-10 | Kanebo, Limited | Organic electrolytic cell |
| US6740454B1 (en) | 1998-07-27 | 2004-05-25 | Kanebo Limited | Organic electrolytic cell with a porous current collector |
| JP2007500922A (en) * | 2003-07-29 | 2007-01-18 | エフエムシー・コーポレイション | Dispersion of lithium metal at the electrode. |
| US7682739B2 (en) | 2004-05-12 | 2010-03-23 | Mitsui Mining & Smelting Co., Ltd. | Negative electrode for nonaqueous secondary battery and process of producing the same |
| JP2009123374A (en) * | 2007-11-12 | 2009-06-04 | Fdk Corp | Nonaqueous electrolyte power storage device |
| JP2009170384A (en) * | 2008-01-21 | 2009-07-30 | Nec Tokin Corp | Lithium secondary battery |
| WO2012105052A1 (en) * | 2011-02-04 | 2012-08-09 | トヨタ自動車株式会社 | Secondary battery |
| KR20130119486A (en) * | 2011-02-04 | 2013-10-31 | 도요타지도샤가부시키가이샤 | Secondary battery |
| JP5787185B2 (en) * | 2011-02-04 | 2015-09-30 | トヨタ自動車株式会社 | Secondary battery |
| JP2013206544A (en) * | 2012-03-27 | 2013-10-07 | Panasonic Corp | Cylindrical lithium ion secondary battery |
| CN104752773A (en) * | 2015-04-01 | 2015-07-01 | 广东烛光新能源科技有限公司 | Preparation method of lithium ion battery |
| WO2018216585A1 (en) * | 2017-05-25 | 2018-11-29 | 株式会社村田製作所 | Non-aqueous electrolyte secondary battery and method for producing non-aqueous electrolyte secondary battery |
| US11831008B2 (en) | 2017-05-25 | 2023-11-28 | Murata Manufacturing Co., Ltd. | Non-aqueous electrolyte secondary battery and method for manufacturing non-aqueous electrolyte secondary battery |
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