JP3393243B2 - Non-aqueous electrolyte secondary battery - Google Patents
Non-aqueous electrolyte secondary batteryInfo
- Publication number
- JP3393243B2 JP3393243B2 JP10640095A JP10640095A JP3393243B2 JP 3393243 B2 JP3393243 B2 JP 3393243B2 JP 10640095 A JP10640095 A JP 10640095A JP 10640095 A JP10640095 A JP 10640095A JP 3393243 B2 JP3393243 B2 JP 3393243B2
- Authority
- JP
- Japan
- Prior art keywords
- negative electrode
- aqueous electrolyte
- current collector
- secondary battery
- electrolyte secondary
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Cell Electrode Carriers And Collectors (AREA)
- Secondary Cells (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Carbon And Carbon Compounds (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は非水電解液二次電池に関
し、特に負極集電体の改良に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolyte secondary battery, and more particularly to improvement of a negative electrode current collector.
【０００２】[0002]
【従来の技術】近年、ビデオカメラやラジオカセット等
のポータブル機器の普及に伴い、使い捨てである一次電
池に代わって、繰り返し使用できる二次電池に対する需
要が高まっている。2. Description of the Related Art In recent years, with the spread of portable devices such as video cameras and radio cassettes, there is an increasing demand for rechargeable secondary batteries instead of disposable primary batteries.
【０００３】現在使用されている二次電池のほとんど
は、アルカリ電解液を用いたニッケル・カドミウム電池
である。しかし、この電池は、電圧が約１．２Ｖであ
り、エネルギー密度を向上させることが困難である。ま
た、常温での自己放電率が１ケ月で２０％以上と高いと
いう欠点もある。Most of the secondary batteries currently used are nickel-cadmium batteries using an alkaline electrolyte. However, this battery has a voltage of about 1.2 V, and it is difficult to improve the energy density. In addition, there is a drawback that the self-discharge rate at room temperature is as high as 20% or more per month.
【０００４】そこで、電解液に非水溶媒を使用し、負極
にリチウム等の軽金属を使用する非水電解液二次電池の
検討がなされている。この非水電解液二次電池は、電圧
が３Ｖと高いため高エネルギー密度を有し、自己放電も
少なく、軽量という長所も有している。しかし、このリ
チウム等を負極に用いる非水電解液二次電池は、充放電
を繰り返すと、負極から金属リチウム等がデンドライト
状に結晶成長して正極に接触し、この結果、電池内部で
短絡が生じるという可能性があり、実用化が困難であ
る。Therefore, a non-aqueous electrolyte secondary battery using a non-aqueous solvent for the electrolyte and a light metal such as lithium for the negative electrode has been studied. This non-aqueous electrolyte secondary battery has the advantages that it has a high energy density because it has a high voltage of 3 V, it has little self-discharge, and it is lightweight. However, in a non-aqueous electrolyte secondary battery using this lithium or the like as a negative electrode, when charge and discharge are repeated, metallic lithium or the like crystallizes in a dendrite form and contacts the positive electrode, and as a result, a short circuit occurs inside the battery. There is a possibility that it will occur, and practical application is difficult.
【０００５】このため、リチウム等を他の金属と合金化
し、この合金を負極に使用するようにした非水電解液二
次電池も検討されている。しかし、この電池では、充放
電を繰り返すと、この負極を構成する合金が微粒子化す
るという問題を有しており、やはり実用化は困難であ
る。Therefore, a non-aqueous electrolyte secondary battery in which lithium or the like is alloyed with another metal and this alloy is used for the negative electrode has also been studied. However, this battery has a problem that the alloy forming the negative electrode becomes fine particles when the charge and discharge are repeated, and it is also difficult to put it into practical use.
【０００６】そこで、さらに、コークス等の炭素質材料
を負極活物質として使用する非水電解液二次電池が提案
されている。この非水電解液二次電池は、リチウムイオ
ンの炭素層間へのドープ・脱ドープを負極反応に利用す
るものであり、金属リチウム、リチウム合金を負極活物
質として使用する場合のような金属リチウムの析出、合
金の微粒子化が生じない。したがって、良好なサイクル
特性が得られる。そして、正極活物質として、例えばＬ
ｉx ＭＯ2 （但し、Ｍは１種類以上の遷移金属を表し、
ｘは０．０５＜ｘ＜１．１０である）で表されるリチウ
ム遷移金属複合酸化物を用いると、電池容量が向上し
て、エネルギー密度が高い非水電解液二次電池を得るこ
とができる。Therefore, a non-aqueous electrolyte secondary battery using a carbonaceous material such as coke as a negative electrode active material has been proposed. This non-aqueous electrolyte secondary battery utilizes doping / de-doping of lithium ions in the carbon layer for the negative electrode reaction, and the metallic lithium or lithium alloy is used as a negative electrode active material. No precipitation or alloy atomization occurs. Therefore, good cycle characteristics can be obtained. Then, as the positive electrode active material, for example, L
i x MO 2 (where M represents one or more kinds of transition metals,
x is 0.05 <x <1.10), the battery capacity is improved and a non-aqueous electrolyte secondary battery with high energy density can be obtained by using the lithium-transition metal composite oxide. it can.
【０００７】ここで、このような炭素質材料を負極活物
質として負極を構成する場合、具体的には炭素質材料を
粉末化し、粉末状の炭素質材料をバインダーとともに溶
剤に分散させて負極合剤塗料調製し、これを負極集電体
に塗布する。これにより、負極活物質がバインダーによ
って集電体表面に保持されたかたちの負極が形成され
る。同様に、たとえばリチウム遷移金属複合酸化物を正
極活物質として正極を構成する場合にも、これを粉末化
し、粉末状のリチウム遷移金属複合酸化物を導電剤、バ
インダーとともに溶剤に分散させて正極合剤塗料を調製
し、これを正極集電体に塗布する。これにより、正極活
物質がバインダーによって正極集電体表面に保持された
かたちの正極が形成される。Here, when such a carbonaceous material is used as a negative electrode active material to form a negative electrode, specifically, the carbonaceous material is powdered, and the powdery carbonaceous material is dispersed in a solvent together with a binder to form a negative electrode mixture. An agent coating material is prepared and applied to the negative electrode current collector. As a result, the negative electrode is formed such that the negative electrode active material is held on the surface of the current collector by the binder. Similarly, for example, when a positive electrode is formed by using a lithium transition metal composite oxide as a positive electrode active material, this is powdered, and the powdery lithium transition metal composite oxide is dispersed in a solvent together with a conductive agent and a binder to mix the positive electrode. An agent paint is prepared and applied to the positive electrode current collector. As a result, the positive electrode is formed such that the positive electrode active material is held on the surface of the positive electrode current collector by the binder.
【０００８】[0008]
【発明が解決しようとする課題】ところで、これら電極
を構成する要素のうち特に負極の集電体には、銅箔が用
いられるのが通常である。これは、銅が電池内で比較的
安定であり、また工業的に１０〜２０μｍ程度の薄膜化
が可能で、しかも価格が安価で汎用性に優れるからであ
る。しかしながら、このうち銅の化学的安定性は、他の
材料に比べれば優位であるということで、電池の集電体
としては十分であるとは言えない。By the way, a copper foil is usually used as a current collector for the negative electrode among the elements constituting these electrodes. This is because copper is relatively stable in the battery, can be industrially formed into a thin film of about 10 to 20 μm, is inexpensive, and is excellent in versatility. However, among them, the chemical stability of copper is superior to that of other materials, and it cannot be said that it is sufficient as a current collector of a battery.
【０００９】すなわち、負極活物質として用いている炭
素質材料は、通常の充放電条件下ではリチウムのドープ
・脱ドープに伴う電位範囲がリチウム基準で０．１〜１
Ｖの範囲内であるが、何らかの異常で過放電状態になっ
た場合には電位が１Ｖを越える。That is, the carbonaceous material used as the negative electrode active material has a potential range of 0.1 to 1 on the basis of lithium when lithium is doped or dedoped under normal charge and discharge conditions.
Although it is within the range of V, the potential exceeds 1 V when an overdischarge state occurs due to some abnormality.
【００１０】銅製の集電体は、負極活物質の電位が０．
１〜１Ｖの範囲内であれば非常に安定しているが、負極
活物質の電位が１Ｖを越え、さらに銅の酸化還元電位に
達すると溶解し始める。その結果、集電体の集電性能が
劣化したり、溶解した銅が正極表面に析出してその性能
に悪影響を及ぼし、電池容量を損なわせる。このよう
に、過放電時に一度劣化した電極の性能は、再び充電を
行ってもほとんど回復せず、容量は大きく劣化したまま
となる。In the current collector made of copper, the potential of the negative electrode active material is 0.
It is very stable in the range of 1 to 1 V, but starts to dissolve when the potential of the negative electrode active material exceeds 1 V and further reaches the oxidation-reduction potential of copper. As a result, the current collecting performance of the current collector is deteriorated, or the dissolved copper is deposited on the surface of the positive electrode to adversely affect its performance, thereby deteriorating the battery capacity. As described above, the performance of the electrode once deteriorated during over-discharging is hardly recovered even when the battery is charged again, and the capacity remains largely deteriorated.
【００１１】そこで、本発明はこのような従来の実情に
鑑みて提案されたものであり、過放電状態になった場合
でも負極の集電体が溶解せず、過放電後においても初期
の容量が維持される非水電解液二次電池を提供すること
を目的とする。Therefore, the present invention has been proposed in view of such a conventional situation, and the current collector of the negative electrode does not dissolve even in the overdischarge state, and the initial capacity is maintained even after the overdischarge. It is an object of the present invention to provide a non-aqueous electrolyte secondary battery in which the above is maintained.
【００１２】[0012]
【課題を解決するための手段】上述の目的を達成するた
めに、本発明者等が鋭意検討を重ねた結果、銅よりさら
に化学的安定性の高いニッケルまたはクロムの金属被膜
で銅箔を被覆するようにすれば、この金属被膜によって
化学的安定性が付与され、過放電状態に耐え得る集電体
が実現するとの知見を得るに至った。In order to achieve the above object, the inventors of the present invention have conducted extensive studies and as a result, as a result, a copper foil is coated with a metal film of nickel or chromium having higher chemical stability than copper. By doing so, it has been found that the metal coating imparts chemical stability and a current collector that can withstand an overdischarge state is realized.
【００１３】本発明はこのような知見に基づいて完成さ
れたものであって、負極活物質が集電体に保持されてな
る負極と、正極と、非水電解液を有してなる非水電解液
二次電池において、上記負極の集電体は、銅箔上にニッ
ケル被膜またはクロム被膜の少なくともいずれかが被覆
されてなることを特徴とするものである。The present invention has been completed based on these findings, and is a non-aqueous electrolyte containing a negative electrode having a negative electrode active material held on a current collector, a positive electrode, and a non-aqueous electrolyte. In the electrolyte secondary battery, the current collector of the negative electrode is characterized in that at least one of a nickel film and a chromium film is coated on a copper foil.
【００１４】本発明が適用される非水電解液二次電池に
おいて、負極は負極活物質が集電体に保持されて構成さ
れる。In the non-aqueous electrolyte secondary battery to which the present invention is applied, the negative electrode is constructed by holding the negative electrode active material on the current collector.
【００１５】本発明では、このような負極の集電体とし
て銅箔上にニッケルまたはクロムよりなる金属被膜が被
覆されてなるものを用いる。この銅箔上に被覆されるニ
ッケルまたはクロムは不動態化する金属であり、化学的
安定性が非常に高い。そのため、これらの金属被膜が被
覆された集電体では、過放電によって負極活物質の電位
が通常より高くなった場合でも、この金属被膜上に薄く
形成された不動態被膜によって保護され、電解液中に銅
が溶解するといったことがない。したがって、過放電後
においてもその集電性能が十分に維持されるとともに、
溶解した銅によって正極性能が悪影響を受けることもな
く、電池の本来持つ容量が保持されることになる。In the present invention, as the current collector for such a negative electrode, a copper foil coated with a metal film made of nickel or chromium is used. Nickel or chromium coated on this copper foil is a passivating metal and has very high chemical stability. Therefore, in the current collector coated with these metal films, even when the potential of the negative electrode active material becomes higher than usual due to overdischarge, it is protected by the passivation film thinly formed on the metal film, There is no chance that copper will dissolve inside. Therefore, the current collecting performance is sufficiently maintained even after the over discharge, and
The positive electrode performance is not adversely affected by the dissolved copper, and the original capacity of the battery is maintained.
【００１６】ここで、化学的安定性の高い集電体を得る
手段としては、この他にニッケル箔またはクロム箔その
ものを集電体に用いることも考えられる、しかし、ニッ
ケルまたはクロムは非常に高価であることから電池の製
造コストの増大に繋がる。これに対して、銅箔上にニッ
ケルまたはクロムが金属被膜として被覆されている集電
体は、比較的安価な銅が主体であり、ニッケル，クロム
の使用量はわずかで済む。したがって、電池の製造コス
トが従来とほとんど変わらず、この点においても有利で
あると言える。なお、ニッケル被膜、クロム被膜はそれ
ぞれ単独で銅箔上に被覆しても良いが、この両方を積層
して銅箔上に被覆しても良い。Here, as a means for obtaining a current collector having high chemical stability, it is conceivable to use nickel foil or chromium foil itself as the current collector, but nickel or chromium is very expensive. Therefore, the manufacturing cost of the battery is increased. On the other hand, the current collector in which nickel or chromium is coated on the copper foil as a metal film is mainly composed of relatively inexpensive copper, and the amount of nickel and chromium used is small. Therefore, the manufacturing cost of the battery is almost the same as the conventional one, and it can be said that this is also advantageous. The nickel coating and the chrome coating may be coated on the copper foil individually, or both may be laminated and coated on the copper foil.
【００１７】このようなニッケルまたはクロムよりなる
金属被膜は例えばメッキ法によって銅箔上に析出形成す
ることができる。このとき金属被膜の厚みは、１μｍ以
上であるのが望ましい。厚みが１μｍ未満の金属被膜
は、均一な膜となり難く、所々にピンホールが生じてし
まう。金属被膜にピンホールが生じていると、過放電時
にその部分から銅が溶出し、電池の性能を劣化させる。The nickel or chromium metal coating can be formed on the copper foil by plating, for example. At this time, the thickness of the metal coating is preferably 1 μm or more. A metal coating having a thickness of less than 1 μm is difficult to form a uniform film, and pinholes are generated in places. When a pinhole is formed in the metal coating, copper is eluted from that portion at the time of over-discharging, which deteriorates the battery performance.
【００１８】負極は、以上のような集電体に負極活物質
が保持されて構成される。The negative electrode is constructed by holding the negative electrode active material on the above current collector.
【００１９】この負極活物質としては、リチウム等をド
ープ・脱ドープ可能な炭素材料が用いられ、例えばポリ
アセチレン、ポリピロール等の導電性ポリマー、あるい
はコークス、ポリマー炭、カーボン・ファイバー等の
他、単位体積当りのエネルギー密度が大きい点から、熱
分解炭素類、コークス類（石油コークス、ピッチコーク
ス、石炭コークス等）、カーボンブラック（アセチレン
ブラック等）、ガラス状炭素、有機高分子材料焼成体
（有機高分子材料を５００℃以上の適当な温度で不活性
ガス気流中、あるいは真空中で焼成したもの）等が好ま
しい。As the negative electrode active material, a carbon material capable of being doped or dedoped with lithium or the like is used. For example, a conductive polymer such as polyacetylene or polypyrrole, coke, polymer charcoal, carbon fiber or the like, and a unit volume In terms of high energy density per unit, pyrolytic carbons, cokes (petroleum coke, pitch coke, coal coke, etc.), carbon black (acetylene black, etc.), glassy carbon, organic polymer material fired body (organic polymer) It is preferable that the material is fired at a suitable temperature of 500 ° C. or higher in an inert gas stream or in a vacuum).
【００２０】一方、正極は、例えばアルミニウム等より
なる集電体に正極活物質が保持されて構成される。On the other hand, the positive electrode is constructed by holding a positive electrode active material on a current collector made of, for example, aluminum.
【００２１】正極活物質としては、二酸化マンガン、五
酸化バナジウムのような遷移金属酸化物や、硫化鉄、硫
化チタンのような遷移金属カルコゲン化物、さらにはこ
れらとリチウムとの複合化合物などを用いることができ
る。特に、高電圧、高エネルギー密度が得られ、サイク
ル特性にも優れることから、リチウム・コバルト複合酸
化物やリチウム・コバルト・ニッケル複合酸化物が望ま
しい。As the positive electrode active material, use is made of transition metal oxides such as manganese dioxide and vanadium pentoxide, transition metal chalcogenides such as iron sulfide and titanium sulfide, and composite compounds of these with lithium. You can In particular, a lithium-cobalt composite oxide and a lithium-cobalt-nickel composite oxide are preferable because they can obtain a high voltage and a high energy density and have excellent cycle characteristics.
【００２２】また、電解液に用いる有機溶媒としては、
特に限定されるものではないが、プロピレンカーボネー
ト、エチレンカーボネート、ブチレンカーボネート、γ
ブチルラクトン、１，２−ジメトキシエタン、１，２−
ジエトキシエタン、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、ジグライム類、トリグライム
類、スルホラン、炭酸ジメチル、炭酸ジエチル、炭酸ジ
プロピル等の単独もしくは二種以上の混合溶媒が使用で
きる。As the organic solvent used for the electrolytic solution,
Although not particularly limited, propylene carbonate, ethylene carbonate, butylene carbonate, γ
Butyl lactone, 1,2-dimethoxyethane, 1,2-
Diethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, diglymes, triglymes, sulfolane, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, etc., alone or in combination of two or more. The mixed solvent of can be used.
【００２３】電解質も従来より公知のものがいずれも使
用でき、ＬｉＣｌＯ4 、ＬｉＡｓＦ6 、ＬｉＰＦ6 、Ｌ
ｉＢＦ4 、ＬｉＢ（Ｃ6 Ｈ5 ）4 、ＬｉＣｌ、ＬｉＢ
ｒ、ＣＨ3 ＳＯ3 Ｌｉ、ＣＦ3 ＳＯ3 Ｌｉ等が用いられ
る。Any known electrolyte can be used as the electrolyte, and LiClO 4 , LiAsF 6 , LiPF 6 , L
iBF 4 , LiB (C 6 H 5 ) 4 , LiCl, LiB
r, CH 3 SO 3 Li, CF 3 SO 3 Li, etc. are used.
【００２４】[0024]
【作用】本発明の非水電解液二次電池では、負極の集電
体として銅箔上にニッケルまたはクロムよりなる金属被
膜が被覆されてなるものを用いる。In the non-aqueous electrolyte secondary battery of the present invention, a copper foil coated with a metal coating made of nickel or chromium is used as the current collector of the negative electrode.
【００２５】この銅箔上に被覆されるニッケルまたはク
ロムは不動態化する金属であることから化学的安定性が
非常に高い。そのため、これらの金属被膜が被覆された
集電体では、過放電によって負極活物質の電位が通常よ
りも高くなった場合でも、この金属被膜上に薄く形成さ
れた不動態被膜によって保護され、電解液中に銅が溶解
するといったことがない。したがって、過放電後におい
てもその集電性能が十分に維持されるとともに、溶解し
た銅によって正極性能が悪影響を受けることもなく、電
池の本来持つ容量が保持されることになる。Nickel or chromium coated on this copper foil is a passivating metal and therefore has very high chemical stability. Therefore, in the current collector coated with these metal films, even when the potential of the negative electrode active material becomes higher than usual due to overdischarge, the current is protected by the passivation film thinly formed on this metal film, and the Copper does not dissolve in the liquid. Therefore, even after the overdischarge, the current collecting performance is sufficiently maintained, the positive electrode performance is not adversely affected by the dissolved copper, and the original capacity of the battery is maintained.
【００２６】[0026]
【実施例】本発明の好適な実施例について実験結果に基
づいて説明する。EXAMPLES Preferred examples of the present invention will be described based on experimental results.
【００２７】本実施例で作製した非水電解液二次電池の
縦断面図を図１に示す。本実施例では、このような構成
の非水電解液二次電池を以下のようにして作製した。FIG. 1 is a vertical cross-sectional view of the non-aqueous electrolyte secondary battery produced in this example. In this example, a non-aqueous electrolyte secondary battery having such a structure was manufactured as follows.
【００２８】実施例１
まず、負極１を作製するために負極集電体９を次のよう
にして作製した。 Example 1 First, in order to manufacture the negative electrode 1, a negative electrode current collector 9 was manufactured as follows.
【００２９】電流密度２Ａ／ｄｍ2なる条件で硫酸銅メ
ッキ浴により、厚さ８μｍの電解銅箔を作製した。続い
て、この銅箔の裏表全面に、電流密度２Ａ／ｄｍ2なる
条件で硫酸ニッケルメッキ浴により、厚さ１．５μｍの
ニッケル被膜を形成し、負極集電体９を作製した。An electrolytic copper foil having a thickness of 8 μm was produced in a copper sulfate plating bath under the condition that the current density was 2 A / dm 2 . Subsequently, a nickel coating having a thickness of 1.5 μm was formed on the entire front and back surfaces of this copper foil with a nickel sulfate plating bath under the condition of a current density of 2 A / dm 2 to prepare a negative electrode current collector 9.
【００３０】次に、下記の塗料組成に準じて各塗料成分
を計り採り、ボールミルにて１０時間混合することで負
極合剤塗料を調製した。Next, each negative electrode mixture coating material was prepared by measuring each coating material component according to the following coating composition and mixing it in a ball mill for 10 hours.
【００３１】
負極合剤塗料組成
カーボン（比表面積：８ｍ2／ｇ） ６０重量部
結合剤（ポリフッ化ビニリデン） ５重量部
溶剤（Ｎ−メチルピロリドン） ３５重量部
そして、この負極合剤塗料を上述のようにして作製した
全厚１０μｍの負極集電体９の両面に、塗布厚１００μ
ｍで塗布乾燥し、帯状負極１を作製した。Negative electrode mixture coating composition Carbon (specific surface area: 8 m 2 / g) 60 parts by weight Binder (polyvinylidene fluoride) 5 parts by weight Solvent (N-methylpyrrolidone) 35 parts by weight 100 μm of the coating thickness on both surfaces of the negative electrode current collector 9 having a total thickness of 10 μm produced as described above.
m was applied and dried to prepare a strip negative electrode 1.
【００３２】一方、正極２は以下のようにして作製し
た。On the other hand, the positive electrode 2 was manufactured as follows.
【００３３】下記の塗料組成に準じて各塗料成分を計り
採り、ボールミルにて１０時間混合することで正極合剤
塗料を調製した。Each of the coating components was weighed according to the following coating composition and mixed in a ball mill for 10 hours to prepare a positive electrode mixture coating composition.
【００３４】
正極合剤塗料組成
ＬｉＣｏＯ2（比表面積：０．４ｍ2／ｇ） ６０重量部
カーボン（比表面積：２５０ｍ2／ｇ） ５重量部
結合剤（ポリフッ化ビニリデン） ５重量部
溶剤（Ｎ−メチルピロリドン） ３０重量部
そして、この正極合剤塗料を正極集電体１０となる厚さ
２０μｍのアルミニウム箔の両面に塗布厚１００μｍで
塗布乾燥し、帯状正極２を作製した。Positive electrode mixture coating composition LiCoO 2 (specific surface area: 0.4 m 2 / g) 60 parts by weight carbon (specific surface area: 250 m 2 / g) 5 parts by weight Binder (polyvinylidene fluoride) 5 parts by weight Solvent (N -Methylpyrrolidone) 30 parts by weight Then, this positive electrode material mixture coating material was applied and dried at a coating thickness of 100 µm on both surfaces of an aluminum foil having a thickness of 20 µm to serve as the positive electrode current collector 10 to produce a strip-shaped positive electrode 2.
【００３５】次に、これらの帯状正極２、帯状負極１を
セパレータ３となる厚さ２５μｍのポリプロピレン製フ
ィルムを介して、積層し、多数回巻回することで、外径
１８ｍｍの渦巻電極体を作製した。Next, the strip-shaped positive electrode 2 and the strip-shaped negative electrode 1 are laminated with a 25 μm-thick polypropylene film serving as the separator 3 and wound many times to form a spiral electrode body having an outer diameter of 18 mm. It was made.
【００３６】そして、この渦巻電極体をニッケルめっき
が施された鉄製電池缶５に収納し、この渦巻型電極体の
上下には絶縁板４を設置した。そして、アルミニウム製
正極リード１２を正極集電体から導出して電池蓋７に溶
接し、ニッケル製負極リード１１を負極集電体から導出
して電池缶５に溶接した。The spiral electrode body was housed in a nickel-plated iron battery can 5, and insulating plates 4 were placed above and below the spiral electrode body. Then, the aluminum positive electrode lead 12 was led out from the positive electrode current collector and welded to the battery lid 7, and the nickel negative electrode lead 11 was led out from the negative electrode current collector and welded to the battery can 5.
【００３７】この渦巻型電極体が収納された電池缶５の
なかに、プロピレンカーボネートとジメチルカーボネー
トが体積比１：１で混合された混合溶媒にＬｉＰＦ6を
１ｍｏｌ／ｌなる濃度で溶解した電解液を注入した。そ
して、電流遮断機構を有する安全弁装置８、電池蓋７を
電池缶５にアスファルトで表面を塗布した絶縁封口ガス
ケット６を介してかしめて固定し、直径１８ｍｍ、高さ
６５ｍｍの円筒形の非水電解液二次電池を作製した。An electrolytic solution prepared by dissolving LiPF 6 at a concentration of 1 mol / l in a mixed solvent in which propylene carbonate and dimethyl carbonate were mixed at a volume ratio of 1: 1 was placed in a battery can 5 in which the spirally wound electrode body was housed. Was injected. Then, the safety valve device 8 having a current cutoff mechanism and the battery lid 7 are caulked and fixed to the battery can 5 through an insulating sealing gasket 6 whose surface is coated with asphalt, and a cylindrical non-aqueous electrolysis having a diameter of 18 mm and a height of 65 mm. A liquid secondary battery was produced.
【００３８】実施例２
負極集電体に形成したニッケル被膜の厚さを、裏表でと
もに１μｍとしたこと以外は実施例１と同様にして非水
電解液二次電池を作製した。 Example 2 A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that the nickel coating formed on the negative electrode current collector had a thickness of 1 μm on both sides.
【００３９】実施例３
負極集電体に形成したニッケル被膜の厚さを、裏表でと
もに２μｍとしたこと以外は実施例１と同様にして非水
電解液二次電池を作製した。 Example 3 A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that the thickness of the nickel coating formed on the negative electrode current collector was 2 μm on both sides.
【００４０】実施例４
負極集電体の裏表両面に、ニッケル被膜の代わりに厚さ
１．５μｍのクロム被膜を形成したこと以外は実施例１
と同様にして非水電解液二次電池を作製した。 Example 4 Example 1 was repeated except that a chromium coating having a thickness of 1.5 μm was formed on both the front and back surfaces of the negative electrode current collector instead of the nickel coating.
A non-aqueous electrolyte secondary battery was prepared in the same manner as in.
【００４１】なお、クロム被膜の形成は、クロム酸メッ
キ溶を用い電流密度１０Ａ／ｄｍ2なる条件で行った。The formation of the chromium film was performed under the conditions of a current density of 10 A / dm 2 using a chromic acid plating solution.
【００４２】実施例５
負極集電体の裏表両面に、厚さ１μｍのニッケル被膜を
形成した後、さらにこの上に厚さ１μｍのクロム被膜を
形成したこと以外は実施例１と同様にして非水電解液二
次電池を作製した。 Example 5 In the same manner as in Example 1 except that a nickel coating having a thickness of 1 μm was formed on both front and rear surfaces of the negative electrode current collector, and then a chromium coating having a thickness of 1 μm was further formed thereon. A water electrolyte secondary battery was produced.
【００４３】実施例６
負極集電体を以下のようにして作製したこと以外は実施
例１と同様にして非水電解液二次電池を作製した。 Example 6 A non-aqueous electrolyte secondary battery was manufactured in the same manner as in Example 1 except that the negative electrode current collector was manufactured as follows.
【００４４】すなわち、圧延により厚さ９μｍの銅箔を
作製し、この銅箔を０．１Ｎ苛性ソーダ水溶液中で、電
圧２０Ｖ、電流密度２０Ａ／ｄｍ2なる条件にてアノー
ド電解研磨した。続いて、この銅箔の裏表全面に、電流
密度２Ａ／ｄｍ2なる条件で硫酸ニッケルメッキ浴によ
り、厚さ１μｍのニッケル被膜を形成し、集電体を作製
した。That is, a copper foil having a thickness of 9 μm was produced by rolling, and this copper foil was subjected to anode electrolytic polishing in a 0.1N caustic soda aqueous solution under the conditions of a voltage of 20 V and a current density of 20 A / dm 2 . Subsequently, a nickel coating film having a thickness of 1 μm was formed on the entire front and back surfaces of this copper foil with a nickel sulfate plating bath under the condition of a current density of 2 A / dm 2 to prepare a current collector.
【００４５】比較例１
負極集電体を作製するに際して、銅箔の厚さを１０μｍ
とするとともにニッケル被膜を形成する代わりに銅箔上
をベンゾトリアゾールで防錆処理すること以外は実施例
１と同様にして非水電解液二次電池を作製した。 Comparative Example 1 In producing a negative electrode current collector, the thickness of the copper foil was set to 10 μm.
A non-aqueous electrolyte secondary battery was manufactured in the same manner as in Example 1 except that the copper foil was rust-proofed with benzotriazole instead of forming the nickel coating.
【００４６】比較例２
負極集電体として、圧延によって作製された厚さ９μｍ
の銅箔を用いること以外は実施例１と同様にして非水電
解液二次電池を作製した。 Comparative Example 2 A negative electrode current collector was manufactured by rolling and had a thickness of 9 μm.
A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that the copper foil in Example 1 was used.
【００４７】このようにして作製された電池について以
下のように過放電特性を調べた。The overdischarge characteristics of the battery thus manufactured were examined as follows.
【００４８】すなわち、電池に上限電圧４．２Ｖ，下限
電圧２．７５Ｖ，充放電電流５００ｍＡなる条件で定電
流充放電サイクルを１０回繰り返し行う。この１０回目
の放電容量を初期容量とする。次に、この放電状態の電
池に、さらに５０Ωの定抵抗で０Ｖまで放電を行うこと
で過放電状態とし、一ヶ月放置する。放置後、再び電池
に、上限電圧４．２Ｖ，下限電圧２．７５Ｖ，充放電電
流５００ｍＡなる条件で定電流充放電を行って放電容量
を測定し、初期容量に対する容量維持率を求めた。その
結果を表１に示す。That is, the constant current charging / discharging cycle is repeated 10 times under the condition that the upper limit voltage is 4.2 V, the lower limit voltage is 2.75 V, and the charging / discharging current is 500 mA. This 10th discharge capacity is used as the initial capacity. Next, the battery in this discharged state is further discharged to 0 V with a constant resistance of 50Ω to be in an overdischarged state, and left for one month. After being left standing, the battery was again charged and discharged at a constant current under the conditions of an upper limit voltage of 4.2 V, a lower limit voltage of 2.75 V, and a charge / discharge current of 500 mA, and the discharge capacity was measured to obtain the capacity retention ratio with respect to the initial capacity. The results are shown in Table 1.
【００４９】[0049]
【表１】 [Table 1]
【００５０】表１に示すように、負極集電体にニッケル
被膜またはクロム被膜の少なくともいずれかが形成され
ている実施例１〜実施例６の電池では、いずれも容量維
持率が９０％前後であり、過放電によってほとんど容量
が劣化しない。これに対して、負極集電体にこれらの金
属被膜が形成されていない比較例２の電池では、容量維
持率が２２％と非常に小さく、過放電による容量劣化が
著しい。As shown in Table 1, in the batteries of Examples 1 to 6 in which at least one of the nickel coating and the chromium coating was formed on the negative electrode current collector, the capacity retention ratio was about 90%. Yes, the capacity hardly deteriorates due to over-discharge. On the other hand, in the battery of Comparative Example 2 in which these metal coatings were not formed on the negative electrode current collector, the capacity retention rate was very small at 22%, and the capacity deterioration due to overdischarge was remarkable.
【００５１】このことから、ニッケル被膜またはクロム
被膜で被覆された銅箔を負極集電体として用いることは
過放電による容量劣化を抑える上できわめて有効である
ことがわかった。From this, it was found that using a copper foil coated with a nickel coating or a chromium coating as a negative electrode current collector is extremely effective in suppressing capacity deterioration due to overdischarge.
【００５２】なお、金属被膜を形成する代わりにベンゾ
トリアゾールで銅箔を処理した比較例１の電池も、やは
り容量維持率が１８％と小さく、過放電によって容量大
きく劣化する。このことから、ベンゾトリアゾールで
は、負極集電体の耐過放電性はほとんど改善できないこ
とが示唆された。The battery of Comparative Example 1 in which the copper foil was treated with benzotriazole instead of forming the metal film also had a small capacity retention rate of 18%, and the capacity was greatly deteriorated due to overdischarge. From this, it was suggested that benzotriazole could hardly improve the overdischarge resistance of the negative electrode current collector.
【００５３】[0053]
【発明の効果】以上の説明からも明らかなように、本発
明の非水電解液二次電池では、負極の集電体として、銅
箔上にニッケル被膜またはクロム被膜の少なくともいず
れかが被覆されたものを用いるので、何らかの異常で過
放電状態となった後にも初期の容量を維持することがで
き、高い信頼性が得られる。As is apparent from the above description, in the non-aqueous electrolyte secondary battery of the present invention, a copper foil is coated with at least either a nickel coating or a chromium coating as a current collector for the negative electrode. Since it is used, the initial capacity can be maintained even after an overdischarge state is caused due to some abnormality, and high reliability can be obtained.
【図１】本発明を適用した非水電解液二次電池の構成を
示す概略縦断面図である。FIG. 1 is a schematic vertical cross-sectional view showing the configuration of a non-aqueous electrolyte secondary battery to which the present invention has been applied.
１ 負極 ２ 正極 1 negative electrode 2 positive electrode
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) H01M 4/64 - 4/84 H01M 10/40 ─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. 7 , DB name) H01M 4/64-4/84 H01M 10/40
Claims (3)
可能な炭素質材料が負極活物質として集電体に保持され
てなる負極と、正極活物質がリチウム遷移金属複合酸化
物からなる正極と、非水電解液を有してなる非水電解液
二次電池において、 上記負極の集電体は、銅箔上にニッケル被膜またはクロ
ム被膜の少なくともいずれかが被覆されてなることを特
徴とする非水電解液二次電池。1. Lithium can be doped and dedoped.
A negative electrode in which a possible carbonaceous material is held as a negative electrode active material by a current collector and a positive electrode active material are lithium transition metal composite oxides.
In a non-aqueous electrolyte secondary battery comprising a positive electrode made of a material and a non-aqueous electrolyte, the current collector of the negative electrode is formed by coating a copper foil with at least one of a nickel coating and a chromium coating. A non-aqueous electrolyte secondary battery characterized by the above.
クロム被膜は、メッキ法により形成されていることを特
徴とする請求項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 nickel film or the chromium film coated on the copper foil is formed by a plating method.
クロム被膜の厚みが、１μｍ以上であることを特徴とす
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 nickel coating or the chromium coating on the copper foil has a thickness of 1 μm or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10640095A JP3393243B2 (en) | 1995-04-28 | 1995-04-28 | Non-aqueous electrolyte secondary battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10640095A JP3393243B2 (en) | 1995-04-28 | 1995-04-28 | Non-aqueous electrolyte secondary battery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08306390A JPH08306390A (en) | 1996-11-22 |
| JP3393243B2 true JP3393243B2 (en) | 2003-04-07 |
Family
ID=14432647
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10640095A Expired - Fee Related JP3393243B2 (en) | 1995-04-28 | 1995-04-28 | Non-aqueous electrolyte secondary battery |
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| Country | Link |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005122297A1 (en) * | 2004-06-10 | 2005-12-22 | Mitsui Mining & Smelting Co., Ltd. | Metal foil with carrier foil, method for producing such metal foil with carrier foil, collector for nonaqueous electrolyte secondary battery using such metal foil with carrier foil |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3742144B2 (en) * | 1996-05-08 | 2006-02-01 | ソニー株式会社 | Nonaqueous electrolyte secondary battery and planar current collector for nonaqueous electrolyte secondary battery |
| JP2001250560A (en) * | 2000-03-08 | 2001-09-14 | Enax Inc | Lithium ion secondary cell |
| US6852449B2 (en) | 2002-08-29 | 2005-02-08 | Quallion Llc | Negative electrode including a carbonaceous material for a nonaqueous battery |
| US6998192B1 (en) | 2002-08-29 | 2006-02-14 | Quallion Llc | Negative electrode for a nonaqueous battery |
| US7174207B2 (en) | 2004-09-23 | 2007-02-06 | Quallion Llc | Implantable defibrillator having reduced battery volume |
| TWI499116B (en) * | 2009-05-08 | 2015-09-01 | Furukawa Electric Co Ltd | A method for manufacturing a negative electrode for a secondary battery, a copper foil for an electrode, a secondary battery, and a negative electrode for a secondary battery |
| JP5437155B2 (en) * | 2009-05-08 | 2014-03-12 | 古河電気工業株式会社 | Secondary battery negative electrode, electrode copper foil, secondary battery, and method for producing secondary battery negative electrode |
| JP5788062B1 (en) * | 2014-06-20 | 2015-09-30 | 古河電気工業株式会社 | Negative electrode current collector for all solid state battery and all solid state battery |
| US9735412B2 (en) * | 2015-09-25 | 2017-08-15 | Intel Corporation | Rechargeable battery and method to suppress dendrite |
| JP7054456B2 (en) * | 2019-01-22 | 2022-04-14 | トヨタ自動車株式会社 | Secondary battery |
-
1995
- 1995-04-28 JP JP10640095A patent/JP3393243B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005122297A1 (en) * | 2004-06-10 | 2005-12-22 | Mitsui Mining & Smelting Co., Ltd. | Metal foil with carrier foil, method for producing such metal foil with carrier foil, collector for nonaqueous electrolyte secondary battery using such metal foil with carrier foil |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH08306390A (en) | 1996-11-22 |
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