JPH07320777A - Nonaqueous electrolytic secondary battery - Google Patents
Nonaqueous electrolytic secondary batteryInfo
- Publication number
- JPH07320777A JPH07320777A JP6112783A JP11278394A JPH07320777A JP H07320777 A JPH07320777 A JP H07320777A JP 6112783 A JP6112783 A JP 6112783A JP 11278394 A JP11278394 A JP 11278394A JP H07320777 A JPH07320777 A JP H07320777A
- Authority
- JP
- Japan
- Prior art keywords
- battery
- negative electrode
- secondary battery
- lithium
- weight
- 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.)
- Withdrawn
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
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、所謂リチウムイオン二
次電池に関し、特に安全性の改善に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called lithium ion secondary battery, and more particularly to improving safety.
【０００２】[0002]
【従来の技術】近年の電子技術のめざましい進歩は、電
子機器の小型・軽量化を次々と実現させている。これに
伴い、上記電子機器に使用されるポータブル用電源とし
ての電池に対しても、ますます小型・軽量且つ高エネル
ギー密度であることが求められるようになっている。2. Description of the Related Art Recent remarkable advances in electronic technology have made electronic devices smaller and lighter one after another. Along with this, batteries for portable power sources used in the above electronic devices are required to be smaller and lighter and have higher energy density.
【０００３】従来、一般用途の二次電池としては、鉛電
池やニッケル・カドミウム電池等の水溶液系二次電池が
主流である。しかし、これらの水溶液系二次電池は、サ
イクル特性には優れているものの、電池重量やエネルギ
ー密度の点で十分満足できるものとは言い難い。また、
環境保全の点からも、新しい電池系の出現が期待されて
いる。Conventionally, an aqueous solution type secondary battery such as a lead battery or a nickel-cadmium battery has been mainly used as a secondary battery for general use. However, although these aqueous secondary batteries have excellent cycle characteristics, it is hard to say that they are sufficiently satisfactory in terms of battery weight and energy density. Also,
From the viewpoint of environmental protection, the emergence of new battery systems is expected.
【０００４】このような状況下で、金属リチウムやリチ
ウム合金のようなリチウムイオンをドープ且つ脱ドープ
可能な物質を負極として使用した非水電解液二次電池
（リチウム二次電池）の研究開発が盛んに行われてい
る。この非水電解液二次電池は、高エネルギー密度を有
し、自己放電が小さい上、軽量という優れた特性を有す
る。Under these circumstances, research and development of a non-aqueous electrolyte secondary battery (lithium secondary battery) using as a negative electrode a substance capable of doping and dedoping lithium ions such as metallic lithium or a lithium alloy has been conducted. It is being actively conducted. This non-aqueous electrolyte secondary battery has a high energy density, a small self-discharge, and a light weight.
【０００５】しかしながら、この非水電解液二次電池に
おいては、充放電時に金属リチウムの溶解、析出を伴う
ため、充電時にリチウムがデンドライト状に結晶成長し
て正極に到達する、即ち内部ショートに至る可能性があ
る。また、このような内部ショートに至る確率は、充放
電サイクルの進行に伴って増加する傾向が見られ、安全
性や信頼性の点で問題があり、この問題が実用化への大
きな障害となっている。However, in this non-aqueous electrolyte secondary battery, since metal lithium is dissolved and deposited during charge / discharge, lithium grows into dendrite-like crystals during charge and reaches the positive electrode, that is, an internal short circuit occurs. there is a possibility. In addition, the probability of such an internal short circuit tends to increase as the charge / discharge cycle progresses, and there is a problem in terms of safety and reliability, and this problem is a major obstacle to commercialization. ing.
【０００６】そこで、上記金属リチウムやリチウム合金
を負極とするリチウム二次電池の持つ問題点を克服した
電池系として、最近、負極に炭素材料を使用した非水電
解液二次電池（所謂、リチウムイオン二次電池）が提案
され、既に実用化されている。Therefore, as a battery system that overcomes the problems of the lithium secondary battery having the above-mentioned metallic lithium or lithium alloy as the negative electrode, recently, a non-aqueous electrolyte secondary battery using a carbon material for the negative electrode (so-called lithium An ion secondary battery) has been proposed and is already in practical use.
【０００７】このリチウムイオン二次電池は、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、適切な電池設計をすることにより、充放
電のどの過程においても、或いは充放電サイクルが進行
しても金属リチウムの析出は見られない。従って、この
リチウムイオン二次電池においては、良好な充放電サイ
クル特性や安全性が得られる。またこのリチウムイオン
二次電池は、急速充放電特性や低温特性が上記リチウム
二次電池に比べて優れている。This lithium ion secondary battery utilizes doping / dedoping of lithium ions into the carbon layer for the negative electrode reaction. By designing the battery appropriately, it can be used in any process of charging / discharging or charging. No metal lithium deposition is observed even if the discharge cycle proceeds. Therefore, in this lithium ion secondary battery, good charge / discharge cycle characteristics and safety can be obtained. Further, this lithium-ion secondary battery is superior in rapid charge / discharge characteristics and low temperature characteristics to the lithium secondary battery.
【０００８】このように、かかるリチウムイオン二次電
池は、上記リチウム電池よりも優れた点を有している
が、有機溶媒系電解液の導電率は水溶液系電解液の導電
率に低く、このため電解液の特性が支配的なこれらの性
能は、水溶液系二次電池であるニッケル・カドミウム電
池には未だ及ばない。As described above, the lithium ion secondary battery has advantages over the lithium battery, but the conductivity of the organic solvent-based electrolytic solution is lower than that of the aqueous solution-based electrolytic solution. Therefore, these performances in which the characteristics of the electrolytic solution are dominant are still inferior to those of the nickel-cadmium battery which is an aqueous secondary battery.
【０００９】[0009]
【発明が解決しようとする課題】上述の問題に対して、
上記リチウムイオン二次電池においては、電解液として
例えば炭酸プロピレンやスルホラン、ジメチルスルホキ
シド等の高誘電率溶媒と１，２−ジメトキシエタン等の
低粘度溶媒との混合溶媒中に支持電解質を溶解したもの
を使用する方法が提案されている。かかる電解液を使用
した電池においては、各構成成分の種類や配合比を選択
することにより、導電率を高くすることが可能である。
このように、高導電性電解液を探索し、それを採用する
ことは、リチウムイオン二次電池の特性の向上を図る上
で有効である。With respect to the above problems,
In the lithium ion secondary battery, a supporting electrolyte is dissolved in a mixed solvent of a high dielectric constant solvent such as propylene carbonate or sulfolane or dimethyl sulfoxide and a low viscosity solvent such as 1,2-dimethoxyethane as an electrolytic solution. A method of using is proposed. In a battery using such an electrolytic solution, it is possible to increase the conductivity by selecting the type and mixing ratio of each constituent component.
As described above, it is effective to search for a high-conductivity electrolytic solution and adopt it in order to improve the characteristics of the lithium-ion secondary battery.
【００１０】しかしながら、高導電率化だけを目的とし
た電解液の変更は、通常使用時には問題は生じないと考
えられるものの、機器の故障やユーザーの誤使用が重な
った場合を想定した、発生確率の非常に低い苛酷な状況
下では多少安全性の低下をもたらす可能性がある。However, although it is considered that there is no problem in normal use when the electrolyte solution is changed only for the purpose of increasing the conductivity, the probability of occurrence is assumed in the case of equipment failure or user misuse. At very low harsh conditions it may result in some reduction in safety.
【００１１】従って、リチウムイオン二次電池の急速充
放電性能や低温特性の更なる改良には、高導電性を有す
る電解液の開発と同時に、安全性を向上させる新たな技
術を開発し、これらの技術を併用することが望ましいと
言える。そこで、本発明はこのような実情に鑑みて提案
されたものであって、高導電性を確保しつつ、安全性の
向上を図ることが可能な非水電解液二次電池を提供する
ことを目的とする。Therefore, in order to further improve the rapid charging / discharging performance and the low temperature characteristics of the lithium ion secondary battery, a new technology for improving safety has been developed at the same time as the development of an electrolyte having high conductivity. It can be said that it is desirable to use these technologies together. Therefore, the present invention has been proposed in view of such circumstances, and provides a non-aqueous electrolyte secondary battery capable of improving safety while ensuring high conductivity. To aim.
【００１２】[0012]
【課題を解決するための手段】本発明者等は、上述の目
的を達成せんものと鋭意研究の結果、炭素材料を負極と
する非水電解液二次電池において、電解液として有機溶
媒中に微量成分を添加した新規な電解液を用いることに
より、高導電性を確保しつつ、安全性の向上を図ること
ができることを見出し、本発明を完成するに至った。Means for Solving the Problems The inventors of the present invention have earnestly studied to achieve the above-mentioned object, and as a result, in a non-aqueous electrolyte secondary battery using a carbon material as a negative electrode, an organic solvent was used as an electrolyte. The inventors have found that it is possible to improve safety while ensuring high conductivity by using a novel electrolytic solution containing a trace amount of components, and have completed the present invention.
【００１３】即ち、本発明は、リチウムをドープ・脱ド
ープし得る炭素質材料を負極活物質とする負極と、リチ
ウムと遷移金属との複合酸化物を正極活物質とする正極
と、非水電解液とを具備してなる非水電解液二次電池に
おいて、上記非水電解液に酪酸メチル及び／又は酢酸ブ
チルが０．５〜３重量％の割合で添加されることを特徴
とするものである。That is, according to the present invention, a negative electrode using a carbonaceous material capable of doping and dedoping lithium as a negative electrode active material, a positive electrode using a composite oxide of lithium and a transition metal as a positive electrode active material, and non-aqueous electrolysis. In a non-aqueous electrolyte secondary battery including a liquid, methyl butyrate and / or butyl acetate is added to the non-aqueous electrolyte in a proportion of 0.5 to 3% by weight. is there.
【００１４】本発明において、負極に使用する負極活剤
としては、充放電反応に伴いリチウムイオンをドープ・
脱ドープ可能な炭素材料が使用可能である。この炭素材
料としては、例えば黒鉛、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（有機高分子材料を不活性
ガス気流中或いは真空中で５００℃以上の適当な温度で
焼成したもの）、炭素繊維等が挙げられる。また、これ
ら炭素材料は、単独で使用しても良く、複合体や混合物
として使用しても良い。In the present invention, the negative electrode activator used for the negative electrode is doped with lithium ions during charge / discharge reaction.
A carbon material that can be dedoped can be used. Examples of the carbon material include graphite, pyrolytic carbons, cokes (petroleum coke, pitch coke, coal coke, etc.),
Carbon black (acetylene black, etc.), glassy carbon, organic polymer material fired body (organic polymer material fired at a suitable temperature of 500 ° C. or higher in an inert gas stream or in a vacuum), carbon fiber, etc. Can be mentioned. In addition, these carbon materials may be used alone or as a composite or mixture.
【００１５】かかる炭素材料としては、Ｘ線回折法によ
る（００２）面の面間隔が０．３７ｎｍ以上、真比重が
１．７未満であり、且つ空気気流中における示差熱分析
で温度７００℃以上に発熱ピークを有しないものが好適
である。Such carbon material has a (002) plane spacing of 0.37 nm or more by X-ray diffractometry, a true specific gravity of less than 1.7, and a temperature of 700 ° C. or more in a differential thermal analysis in an air stream. Those having no exothermic peak are preferred.
【００１６】このような性質を有する炭素材料として
は、有機材料を焼成等の手法により炭素化して得られる
ものが挙げられる。上記炭素化に際し、出発原料として
は、フルフリルアルコール或いはフルフラールのホモモ
ノマー、コポリマーよりなるフラン樹脂等が好適であ
る。具体的に例示するならば、フルフラール＋フェノー
ル、フルフリルアルコール＋ジメチロール尿素、フルフ
リルアルコール、フルフリルアルコール＋ホルムアルデ
ヒド、フルフリルアルコール＋フルフラール、フルフラ
ール＋ケトン類等よりなる重合体がリチウムイオン二次
電池における負極材料として非常に良好な特性を示す。Examples of the carbon material having such a property include those obtained by carbonizing an organic material by a method such as firing. In the above carbonization, as a starting material, furfuryl alcohol or furfural homomonomer, furan resin composed of copolymer, and the like are preferable. As a specific example, a polymer composed of furfural + phenol, furfuryl alcohol + dimethylol urea, furfuryl alcohol, furfuryl alcohol + formaldehyde, furfuryl alcohol + furfural, furfural + ketones, etc. is a lithium ion secondary battery. Shows very good characteristics as a negative electrode material.
【００１７】或いは、原料として水素／炭素原子比０．
６〜０．８の石油ピッチを用い、これに酸素を含む官能
基を導入し、所謂酸素架橋を施して酸素含有量１０〜２
０重量％の前駆体とした後、焼成して得られる炭素質材
料も好適である。ここで、石油ピッチは、コールター
ル、エチレンボトム油、石油等の高温熱分解で得られる
タール類、アスファルト等により蒸留（真空蒸留、常圧
蒸留、スチーム蒸留）、熱重縮合、抽出、化学重縮合等
の操作によって得られるもの等が挙げられる。Alternatively, as a raw material, a hydrogen / carbon atomic ratio of 0.
A petroleum pitch of 6 to 0.8 is used, a functional group containing oxygen is introduced into the pitch, and so-called oxygen crosslinking is performed to obtain an oxygen content of 10 to 2
A carbonaceous material obtained by making 0% by weight of the precursor and then calcining is also suitable. Here, petroleum pitch is distilled (vacuum distillation, atmospheric distillation, steam distillation), thermal polycondensation, extraction, chemical polycondensation with coal tar, ethylene bottom oil, tars obtained by high-temperature thermal decomposition of petroleum, asphalt, etc. Examples thereof include those obtained by operations such as condensation.
【００１８】また、これらの石油ピッチに酸素を含む官
能基を導入する具体的な手段は限定されないが、例えば
硝酸、混酸、硫酸、次亜塩素酸等の水溶液により湿式
法、或いは酸化性ガス（空気、酸素）による乾式法、更
に硫黄、硝酸アンモニア、過硫酸アンモニア、酸化第二
鉄等の固体試薬による反応等が用いられる。The specific means for introducing a functional group containing oxygen into these petroleum pitches is not limited, but, for example, a wet method using an aqueous solution of nitric acid, mixed acid, sulfuric acid, hypochlorous acid, or an oxidizing gas ( A dry method using air, oxygen), a reaction with a solid reagent such as sulfur, ammonium nitrate, ammonium persulfate, ferric oxide, or the like is used.
【００１９】更には、前記フラン樹脂や石油ピッチ等を
炭素化する際に、リン化合物或いはホウ素化合物を添加
することにより、リチウムドープ量を大きなものとした
炭素材料も負極材料として好適である。Further, a carbon material having a large lithium doping amount by adding a phosphorus compound or a boron compound when carbonizing the furan resin, petroleum pitch or the like is also suitable as a negative electrode material.
【００２０】上記リン化合物としては、五酸化リン等の
リンの酸化物、オルトリン酸等のオキソ酸やその塩等が
挙げられるが、取り扱い易さの点からリン酸化物及びり
ん酸が好適である。この場合、リン化合物の添加量は、
有機材料もしくは炭素材料に対してリン換算で０．２〜
３０重量％、好ましくは０．５〜１５重量％、また負極
炭素材料中に残存するリンの割合は、０．２〜９．０重
量％、好ましくは０．３〜５重量％とする。Examples of the above-mentioned phosphorus compounds include phosphorus oxides such as phosphorus pentoxide, oxo acids such as orthophosphoric acid and salts thereof, and phosphorus oxides and phosphoric acid are preferable from the viewpoint of easy handling. . In this case, the added amount of phosphorus compound is
0.2 ~ in terms of phosphorus for organic materials or carbon materials
30% by weight, preferably 0.5 to 15% by weight, and the proportion of phosphorus remaining in the negative electrode carbon material is 0.2 to 9.0% by weight, preferably 0.3 to 5% by weight.
【００２１】上記ホウ素化合物としては、ホウ素の酸化
物、ホウ素を水溶液の形で添加することができる。この
場合、ホウ素化合物の添加量は、有機材料もしくは炭素
材料に対してホウ素換算で０．２〜３０重量％、好まし
くは０．５〜１５重量％、また負極炭素材料中に残存す
るホウ素の割合は、０．２〜９．０重量％、好ましくは
０．３〜５重量％とする。As the above-mentioned boron compound, an oxide of boron or boron can be added in the form of an aqueous solution. In this case, the addition amount of the boron compound is 0.2 to 30% by weight, preferably 0.5 to 15% by weight, in terms of boron with respect to the organic material or the carbon material, and the proportion of boron remaining in the negative electrode carbon material. Is 0.2 to 9.0% by weight, preferably 0.3 to 5% by weight.
【００２２】また、焼成時に発生する種々の揮発成分を
効率良く除去することにより、リチウムドープ能力を向
上させることが可能であることから、焼成時の雰囲気条
件も重量である。この焼成時の雰囲気としては、不活性
ガス雰囲気が好ましく、原料１ｇ当たり０．１ｃｍ3 ／
分以上の不活性ガス気流中で行うことがより好ましい。
更に、真空排気を行いながら焼成する方法は、揮発成分
の影響を殆ど受けず、最も好ましい方法である。Further, since the lithium doping ability can be improved by efficiently removing various volatile components generated during firing, the atmospheric condition during firing is also heavy. The atmosphere during this firing is preferably an inert gas atmosphere, and is 0.1 cm 3 / g of the raw material.
It is more preferable to carry out in an inert gas flow of not less than a minute.
Further, the method of firing while evacuation is the most preferable method because it is hardly affected by volatile components.
【００２３】一方、正極に使用する正極活物質として
は、ドープ・脱ドープ可能なリチウムを多く含むことが
好ましく、例えば一般式ＬｉＭＯ2 （Ｍは１種以上の遷
移金属、好ましくはＣｏ、Ｎｉ、Ｍｎの少なくとも１種
を表す。）で表される、リチウムと遷移金属からなる複
合酸化物やリチウムを含んだ層間化合物等が好適であ
る。On the other hand, the positive electrode active material used for the positive electrode preferably contains a large amount of lithium that can be doped and dedoped, and has, for example, the general formula LiMO 2 (M is one or more transition metals, preferably Co, Ni, A composite oxide of lithium and a transition metal, an intercalation compound containing lithium, or the like, which is represented by at least one of Mn) is preferable.
【００２４】上記リチウムと遷移金属からなる複合酸化
物は、例えばリチウム、ニッケルやコバルト等の遷移金
属の水酸化物、酸化物、炭酸塩等の塩を出発原料とし、
各化合物を所定の組成比で混合し、６００〜１０００℃
の温度範囲で焼成することにより得られる。The above-mentioned composite oxide composed of lithium and a transition metal is prepared by using a salt such as a hydroxide, oxide or carbonate of a transition metal such as lithium or nickel or cobalt as a starting material.
Each compound is mixed at a predetermined composition ratio, and 600 to 1000 ° C.
It is obtained by firing in the temperature range of.
【００２５】本発明においては、かかる非水電解液二次
電池の電解液として、リチウム塩を電解質とし、これを
微量成分が添加された有機溶媒に溶解させたものが使用
される。ここで、炭素材料を負極とする非水電解液二次
電池において、安全性の向上を図る技術としては、例え
ば特開平４−２８４３７４号公報等に開示されるよう
に、電解液として酢酸プロピレンとエステル化合物との
混合溶媒を用いる方法等が知られている。In the present invention, as an electrolytic solution for such a non-aqueous electrolytic solution secondary battery, a lithium salt is used as an electrolyte, and this is dissolved in an organic solvent to which trace components are added. Here, in a non-aqueous electrolyte secondary battery using a carbon material as a negative electrode, as a technique for improving safety, propylene acetate is used as an electrolyte as disclosed in, for example, JP-A-4-284374. A method of using a mixed solvent with an ester compound is known.
【００２６】これに対して、本発明では、従来公知の有
機溶媒中に上述のような微量成分が添加された、全く新
規な電解液が使用される。これにより、高導電性を確保
しつつ、苛酷な状況下での使用時においても優れた安全
性を得ることができる。On the other hand, in the present invention, a completely novel electrolytic solution in which the above-mentioned trace components are added to a conventionally known organic solvent is used. As a result, it is possible to secure high conductivity and obtain excellent safety even when used under severe conditions.
【００２７】かかる電解液において、上記微量成分とし
ては、酪酸メチル、酢酸ブチルが使用される。これら酪
酸メチル、酢酸ブチルは、それぞれ単独で添加されても
良く、又は両者を混合して添加されても良い。この時、
上記酪酸メチル、酢酸ブチルの添加量は、０．５〜３重
量％の範囲とされる。上記酪酸メチル、酢酸ブチルの添
加量が０．５重量％よりも少ないと、十分な安全性を確
保することができず、逆に３重量％を越えると、高温保
存後の容量が低下する。なお、これら酪酸メチルと酢酸
ブチルを混合して用いる場合には、混合物としての添加
量の合計が単独で使用した場合の添加量の範囲内とされ
る。In the electrolytic solution, methyl butyrate and butyl acetate are used as the trace components. These methyl butyrate and butyl acetate may be added individually or as a mixture of both. At this time,
The amount of methyl butyrate and butyl acetate added is in the range of 0.5 to 3% by weight. If the amount of methyl butyrate or butyl acetate added is less than 0.5% by weight, sufficient safety cannot be ensured. On the contrary, if it exceeds 3% by weight, the capacity after high-temperature storage decreases. When these methyl butyrate and butyl acetate are used as a mixture, the total addition amount of the mixture is within the range of the addition amount when used alone.
【００２８】上記有機溶媒としては、特に限定されず、
通常この種の非水電解液二次電池において用いられてい
るものがいずれも使用可能である。具体的に例示するな
らば、エチレンカーボネート、プロピレンカーボネー
ト、ジメチルカーボネート、ジエチルカーボネート、メ
チルエチルカーボネート、メチルプロピルカーボネー
ト、１，２−ジメトキシエタン、１，２−ジエトキシエ
タン、スルホラン、メチルスルホラン等が挙げられる。
なお、これら有機溶媒は、単独で使用しても良く、二種
類以上の溶媒を適当な比率で混合して使用しても良い。
中でも、高い導電性を示す電解液を構成する上で、鎖状
炭酸エステルを含む混合溶媒は好適であり、特に非対称
鎖状炭酸エステルは最適な混合溶媒成分の一つである。The organic solvent is not particularly limited,
Any of those normally used in this type of non-aqueous electrolyte secondary battery can be used. Specific examples include ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methylethyl carbonate, methylpropyl carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, sulfolane, and methylsulfolane. To be
These organic solvents may be used alone, or two or more kinds of solvents may be mixed at an appropriate ratio and used.
Among them, a mixed solvent containing a chain ester carbonate is suitable for forming an electrolytic solution having high conductivity, and an asymmetric chain ester carbonate is one of the most suitable mixed solvent components.
【００２９】また、上記電解質としては、ＬｉＰＦ6 が
好適であるが、この他にも通常この種の電池に使用され
るものであればいずれも使用可能であり、例えばＬｉＣ
ｌＯ 4 、ＬｉＡｓＦ6 、ＬｉＢＦ4 、ＬｉＢ（Ｃ
6 Ｈ5 ）4 、ＬｉＣｌ、ＬｉＢｒ、ＬｉＳＯ3 ＣＨ3 、
ＬｉＳＯ3 ＣＦ3 、ＬｉＮ（ＳＯ2 ＣＦ3 ）2 、ＬｉＣ
（ＳＯ2 ＣＦ3 ）3 等が挙げられる。Further, as the electrolyte, LiPF6But
Suitable, but not usually used for this type of battery
Any material can be used, such as LiC
10 Four, LiAsF6, LiBFFour, LiB (C
6HFive)Four, LiCl, LiBr, LiSO3CH3,
LiSO3CF3, LiN (SO2CF3)2, LiC
(SO2CF3)3Etc.
【００３０】また、本発明の非水電解液二次電池におい
ては、より安全性の高い密閉型非水電解液二次電池を得
るために、過充電時の異常時に電池内圧上昇に応じて電
流を遮断を設けることが望ましい。Further, in the non-aqueous electrolyte secondary battery of the present invention, in order to obtain a safer sealed non-aqueous electrolyte secondary battery, in order to obtain a safer non-aqueous electrolyte secondary battery, the current is increased according to the increase in the battery internal pressure at the time of overcharge It is desirable to provide a shutoff.
【００３１】[0031]
【作用】負極活物質として炭素材料を用いた非水電解液
二次電池において、電解液中に微量成分として酪酸メチ
ル又は／及び酢酸ブチルを所定の割合で添加することに
より、高導電性が確保されると同時に、安全性が向上す
る。[Function] In a non-aqueous electrolyte secondary battery using a carbon material as a negative electrode active material, high conductivity is ensured by adding methyl butyrate and / or butyl acetate as a trace component to the electrolyte at a predetermined ratio. At the same time, safety is improved.
【００３２】[0032]
【実施例】以下、本発明の具体的な実施例について説明
するが、本発明はこの実施例に限定されるものではない
ことはいうまでもない。EXAMPLES Hereinafter, specific examples of the present invention will be described, but it goes without saying that the present invention is not limited to these examples.
【００３３】先ず、後述の各実施例において作製した非
水電解液二次電池の構造を説明する。この非水電解液二
次電池は、図１に示すように、負極集電体１０に負極活
物質を塗布してなる負極１と、正極集電体１１に正極活
物質を塗布してなる正極２とを、セパレータ３を介して
巻回し、この巻回体の上下に絶縁板４を載置した状態で
電池缶５に収納してなるものである。First, the structure of the non-aqueous electrolyte secondary battery produced in each of the examples described below will be described. As shown in FIG. 1, the non-aqueous electrolyte secondary battery includes a negative electrode 1 formed by coating a negative electrode current collector 10 with a negative electrode active material, and a positive electrode formed by coating a positive electrode current collector 11 with a positive electrode active material. 2 and 2 are wound via a separator 3, and the insulating plate 4 is placed on the upper and lower sides of the wound body and housed in a battery can 5.
【００３４】上記電池缶５には、電池蓋７が封口ガスケ
ット６を介してかしこめることによって取付けられ、そ
れぞれ負極リード１２及び正極リード１３を介して負極
１或いは正極２と電気的に接続され、電池の負極或いは
正極として機能するように構成されている。A battery lid 7 is attached to the battery can 5 by caulking it through a sealing gasket 6, and is electrically connected to the negative electrode 1 or the positive electrode 2 via a negative electrode lead 12 and a positive electrode lead 13, respectively. , And is configured to function as a negative electrode or a positive electrode of a battery.
【００３５】そして、本実施例の非水電解液二次電池で
は、前記正極リード１３は安全弁装置８に溶接されて取
付けられ、この安全弁装置８を介して電池蓋７との電気
的接続が図られている。このような構成を有する非水電
解液二次電池においては、電池内の圧力が上昇すると、
上記安全弁装置８が押し上げられて変形する。すると、
上記正極リード１３が上記安全弁装置８と溶接された部
分を残して切断され、電流が遮断される。In the non-aqueous electrolyte secondary battery of this embodiment, the positive electrode lead 13 is attached to the safety valve device 8 by welding, and electrical connection with the battery lid 7 is achieved through the safety valve device 8. Has been. In the non-aqueous electrolyte secondary battery having such a configuration, when the pressure in the battery rises,
The safety valve device 8 is pushed up and deforms. Then,
The positive electrode lead 13 is cut off except for the portion welded to the safety valve device 8, and the current is cut off.
【００３６】次に、負極の作製方法について説明する。
出発原料としてＨ／Ｃ原子比が０．６〜０．８の範囲か
ら適当に選んだ石油ピッチを用い、該石油ピッチを空気
気流中で酸化処理して炭素前駆体を得た。なお、この炭
素前駆体のキノリン不溶分（ＪＩＳ遠心法：Ｋ２４２５
−１９８３）は８０％であり、また酸素含有率（有機元
素分析法による）は１６重量％であった。Next, a method of manufacturing the negative electrode will be described.
A petroleum pitch appropriately selected from the range of H / C atomic ratio of 0.6 to 0.8 was used as a starting material, and the petroleum pitch was oxidized in an air stream to obtain a carbon precursor. The quinoline insoluble matter of this carbon precursor (JIS centrifugal method: K2425
-1983) was 80% and the oxygen content (by organic elemental analysis) was 16% by weight.
【００３７】そして、この炭素前駆体を不活性ガス雰囲
気中で温度１０００℃にて焼成し、ガラス状炭素に近い
性質を持った炭素質材料を得た。この炭素質材料につい
て粉末Ｘ線回折測定を行ったところ、（００２）面の面
間隔は０．３８ｎｍであった。また、ピクノメータ法に
よる真比重は１．５４であった。Then, this carbon precursor was fired at a temperature of 1000 ° C. in an inert gas atmosphere to obtain a carbonaceous material having properties close to those of glassy carbon. When powder X-ray diffraction measurement was performed on this carbonaceous material, the spacing between (002) planes was 0.38 nm. The true specific gravity by the pycnometer method was 1.54.
【００３８】続いて、上記炭素質材料を粉砕し、平均粒
径２０μｍの炭素材料粉末を作製した。そして、得られ
た炭素材料粉末を負極活物質担持体とし、該炭素材料粉
末を９０重量部、結着剤としてフッ化ビニリデン樹脂１
０重量部を混合し、負極合剤を調製した。更に、この負
極合剤を溶剤であるＮ−メチル−２−ピロリドンに分散
させてスラリー（ペースト状）にした。Subsequently, the above carbonaceous material was pulverized to prepare a carbon material powder having an average particle size of 20 μm. Then, the obtained carbon material powder was used as a negative electrode active material carrier, 90 parts by weight of the carbon material powder, and a vinylidene fluoride resin 1 as a binder.
0 parts by weight were mixed to prepare a negative electrode mixture. Further, this negative electrode mixture was dispersed in N-methyl-2-pyrrolidone as a solvent to form a slurry (paste form).
【００３９】次いで、負極集電体として厚さ１０μｍの
帯状の銅箔を用い、この負極集電体の両面に均一に上記
スラリーを塗布し、乾燥後、加圧成型して帯状負極を作
製した。Next, a strip-shaped copper foil having a thickness of 10 μm was used as a negative electrode current collector, the above slurry was uniformly applied to both surfaces of this negative electrode current collector, dried and pressure-molded to produce a strip negative electrode. .
【００４０】また、正極の作製方法について説明する。
炭酸リチウム０．５モルと炭酸コバルト１モルを混合
し、温度９００℃の空気中で５時間焼成してＬｉＣｏＯ
2 を得た。得られたＬｉＣｏＯ2 について粉末Ｘ線回折
測定を行ったところ、ＪＣＰＤＳファイルに登録された
ＬｉＣｏＯ2 のピクとよく一致した。A method of manufacturing the positive electrode will be described.
0.5 mol of lithium carbonate and 1 mol of cobalt carbonate are mixed and fired in air at a temperature of 900 ° C. for 5 hours to obtain LiCoO 2.
Got 2 When the LiCoO 2 obtained was subjected to powder X-ray diffraction measurements were in good agreement with the LiCoO 2 registered in JCPDS file pixels.
【００４１】そして、このＬｉＣｏＯ2 を粉砕し、平均
粒径２０μｍのＬｉＣｏＯ2 粉末を得た。Then, this LiCoO 2 was pulverized to obtain LiCoO 2 powder having an average particle size of 20 μm.
【００４２】続いて、上記ＬｉＣｏＯ2 粉末９５重量部
と炭酸リチウム粉末５重量部からなる混合物を９１重量
部、導電剤としてグラファイト６重量部、結着剤として
フッ化ビニリデン樹脂３重量部を混合して正極合剤を調
製した。更に、この正極合剤を溶剤であるＮ−メチル−
２−ピロリドンに分散させてスラリー（ペースト状）に
した。Subsequently, 91 parts by weight of a mixture of 95 parts by weight of the LiCoO 2 powder and 5 parts by weight of lithium carbonate powder, 6 parts by weight of graphite as a conductive agent, and 3 parts by weight of vinylidene fluoride resin as a binder were mixed. Then, a positive electrode mixture was prepared. Furthermore, this positive electrode mixture was mixed with N-methyl-
It was dispersed in 2-pyrrolidone to obtain a slurry (paste form).
【００４３】次いで、正極集電体として厚さ２０μｍの
帯状のアルミニウム箔を用い、この正極集電体の両面に
均一に上記スラリーを塗布し、乾燥後、加圧成型して帯
状正極を作製した。Next, a strip-shaped aluminum foil having a thickness of 20 μm was used as a positive electrode current collector, the above slurry was uniformly applied to both surfaces of this positive electrode current collector, dried and then pressure-molded to produce a strip positive electrode. .
【００４４】実施例１ 上述のようにして作製した帯状負極、帯状正極及び微多
孔性ポリプロピレンフィルムからなるセパレータを帯状
負極、セパレータ、帯状正極の順に積層してから多数巻
回し、最外周の巻き終わり部を粘着テープで固定して、
外径１８ｍｍの渦巻式電極体を作製した。 Example 1 A separator composed of the strip negative electrode, the strip positive electrode and the microporous polypropylene film produced as described above was laminated in this order on the strip negative electrode, the separator and the strip positive electrode, and then wound a large number of times to finish the outermost winding. Fix the part with adhesive tape,
A spiral electrode body having an outer diameter of 18 mm was produced.
【００４５】そして、この渦巻式電極体をニッケルメッ
キを施した鉄製の電池缶に収納した。その後、上記渦巻
式電極体の上下両面に絶縁板を配置し、正極及び負極の
集電を行うために、アルミニウム製正極リードは正極集
電体から導出して、電池蓋と電気的な導通が確保された
安全弁装置の突起部に、またニッケル製負極リードは負
極集電体から導出して電池缶の底部にそれぞれ溶接し
た。Then, the spirally wound electrode body was housed in a nickel-plated iron battery can. After that, insulating plates are arranged on the upper and lower surfaces of the spirally wound electrode body, and in order to collect the positive electrode and the negative electrode, the aluminum positive electrode lead is led out from the positive electrode current collector and electrically connected to the battery lid. The nickel alloy negative electrode lead was led out from the negative electrode current collector and welded to the protrusion of the safety valve device thus secured, and to the bottom of the battery can.
【００４６】更に、電解液としてプロピレンカーボネー
トとメチルエチルカーボネートとの混合溶媒中に支持電
解質ＬｉＰＦ6 を１モル／ｌの割合で溶解させたものを
用い、この電解液中に酪酸メチルを０．５重量％の割合
で添加し、よく混合した後、上記電池缶の中に注入し
た。Further, as the electrolytic solution, a supporting electrolyte LiPF 6 dissolved in a mixed solvent of propylene carbonate and methyl ethyl carbonate at a ratio of 1 mol / l was used, and methyl butyrate of 0.5 mol was added to the electrolytic solution. The mixture was added at a weight percentage, mixed well, and then poured into the battery can.
【００４７】そして、アスファルトで表面を塗布した絶
縁封口ガスケットを介して上記電池缶をかしめることで
電流遮断機構を有する上記安全弁装置、ＰＣＴ素子並び
に電池蓋を固定し、電池内の気密性を保持させて、直径
１８ｍｍ、高さ６５ｍｍの円筒型リチウムイオン二次電
池を作製した。Then, the safety valve device having a current interruption mechanism, the PCT element, and the battery lid are fixed by caulking the battery can through an insulating sealing gasket whose surface is coated with asphalt, thereby maintaining airtightness in the battery. Then, a cylindrical lithium ion secondary battery having a diameter of 18 mm and a height of 65 mm was produced.
【００４８】そこで、以上のようにして作製した電池に
ついて、電池容量、過充電試験時の電池表面温度及び高
温保存による電池容量への影響を調べた。なお、充電は
定電圧電流法とし、上限電圧を４．２Ｖ、定電流領域で
の電流を１Ａに設定し、充電時間は２．５時間とした。
また、放電は０．７Ａ定電流で行い、終止電圧は２．７
５Ｖとした。Therefore, with respect to the battery manufactured as described above, the influences on the battery capacity, the battery surface temperature during the overcharge test, and the high temperature storage on the battery capacity were examined. Note that the charging was performed by a constant voltage current method, the upper limit voltage was set to 4.2 V, the current in the constant current region was set to 1 A, and the charging time was 2.5 hours.
Also, the discharge is performed at a constant current of 0.7 A, and the final voltage is 2.7.
It was set to 5V.
【００４９】過充電試験は、通常充電した電池を用い、
充電器の上限電圧の設定を故意に外し、３Ａ定電流で過
充電領域の充電を行った。そして、電池缶の表面に熱電
対の測定点を固定して、過充電試験中における電池表面
温度の経時変化を測定し、最高温度を求めた。The overcharge test uses a normally charged battery,
The upper limit voltage of the charger was deliberately removed to charge the overcharge region at a constant current of 3A. Then, the thermocouple measurement point was fixed on the surface of the battery can, and the change over time of the battery surface temperature during the overcharge test was measured to determine the maximum temperature.
【００５０】高温保存による電池容量への影響は、通常
充電した電池を温度４５℃の環境下に１ヵ月放置した
後、一旦放電し、その後数回の通常充放電を繰り返し、
保存前後の電池容量の比較から容量回復率を求めること
によって評価した。The influence of high temperature storage on the battery capacity is that a normally charged battery is left in an environment of a temperature of 45 ° C. for one month, then discharged once and then repeatedly charged and discharged several times.
It was evaluated by calculating the capacity recovery rate from the comparison of the battery capacities before and after storage.
【００５１】実施例２ 上記実施例１において電解液に添加する酪酸メチルの割
合を１．０重量％に変え、その他は上記実施例１と同様
にして円筒型電池を作製し、上述と同様の条件で電池容
量、過充電試験時の電池表面温度及び高温保存による電
池容量への影響を調べた。 Example 2 A cylindrical battery was prepared in the same manner as in Example 1 except that the proportion of methyl butyrate added to the electrolytic solution in Example 1 was changed to 1.0% by weight. Under the conditions, the influences of the battery capacity, the battery surface temperature during the overcharge test and the battery capacity by the high temperature storage were examined.
【００５２】実施例３ 上記実施例１において電解液に添加する酪酸メチルの割
合を３．０重量％に変え、その他は上記実施例１と同様
にして円筒型電池を作製し、上述と同様の条件で電池容
量、過充電試験時の電池表面温度及び高温保存による電
池容量への影響を調べた。 Example 3 A cylindrical battery was prepared in the same manner as in Example 1 except that the proportion of methyl butyrate added to the electrolytic solution in Example 1 was changed to 3.0% by weight. Under the conditions, the influences of the battery capacity, the battery surface temperature during the overcharge test and the battery capacity by the high temperature storage were examined.
【００５３】比較例１ 上記実施例１における電解液に添加成分を加えなかった
以外は上記実施例１と同様にして円筒型電池を作製し、
上述と同様の条件で電池容量、過充電試験時の電池表面
温度及び高温保存による電池容量への影響を調べた。 Comparative Example 1 A cylindrical battery was prepared in the same manner as in Example 1 except that no additive component was added to the electrolytic solution in Example 1 above.
Under the same conditions as above, the influences of the battery capacity, the battery surface temperature during the overcharge test and the high temperature storage on the battery capacity were examined.
【００５４】比較例２ 上記実施例１において電解液に添加する酪酸メチルの割
合を５．０重量％に変え、その他は上記実施例１と同様
にして円筒型電池を作製し、上述と同様の条件で電池容
量、過充電試験時の電池表面温度及び高温保存による電
池容量への影響を調べた。 Comparative Example 2 A cylindrical battery was prepared in the same manner as in Example 1 except that the proportion of methyl butyrate added to the electrolytic solution in Example 1 was changed to 5.0% by weight. Under the conditions, the influences of the battery capacity, the battery surface temperature during the overcharge test and the battery capacity by the high temperature storage were examined.
【００５５】下記の表１に、各実施例１〜３及び比較例
１，２において作製した電池の初期容量、過充電中にお
ける電池表面温度の最高値及び高温保存後の容量回復率
をそれぞれ示した。Table 1 below shows the initial capacity of the batteries prepared in Examples 1 to 3 and Comparative Examples 1 and 2, the maximum value of the battery surface temperature during overcharge, and the capacity recovery rate after high temperature storage. It was
【００５６】[0056]
【表１】 [Table 1]
【００５７】表１に示すように、電解液に酪酸メチルを
添加した実施例１〜３及び比較例２では、添加成分を加
えなかった電解液を使用した場合（比較例１）に比べ
て、過充電中における電池表面温度の最高値が低く抑え
られており、良好な安全性が得られることが判った。ま
た、上記実施例１〜３及び比較例２の結果から、電解液
に酪酸メチルを添加しても、容量に対する悪影響は見ら
れなかった。As shown in Table 1, in Examples 1 to 3 and Comparative Example 2 in which methyl butyrate was added to the electrolytic solution, as compared with the case of using the electrolytic solution containing no additional component (Comparative Example 1), It was found that the maximum value of the battery surface temperature during overcharging was kept low, and good safety was obtained. Further, from the results of Examples 1 to 3 and Comparative Example 2 above, no adverse effect on the capacity was observed even when methyl butyrate was added to the electrolytic solution.
【００５８】更に、高温保存後の容量回復率は、酪酸メ
チルの添加量が少ない電池では、添加成分を加えていな
い電解液を使用した電池よりも高い値を示したが、添加
量が増加するにつれて、若干低下する傾向が見られ、酪
酸メチルを５．０重量％添加した比較例２では、容量回
復率が８０％を下回ってしまった。Further, the capacity recovery rate after storage at high temperature was higher in the battery containing less methyl butyrate than in the battery using the electrolyte solution containing no additive component, but the additive amount was increased. As a result, the tendency of a slight decrease was observed, and in Comparative Example 2 in which 5.0% by weight of methyl butyrate was added, the capacity recovery rate was below 80%.
【００５９】このことから、酪酸メチルの添加量には最
適値が存在し、添加量は電解液に対して０．５〜３．０
重量％とすることが必要であることが判った。更に、上
記酪酸メチルの添加量を０．５〜２．０重量％とするこ
とにより、過充電中における電池表面温度の上昇を抑え
ることができるだけでなく、保存後の容量回復率を向上
させることができることが判った。From this fact, there is an optimum value for the amount of methyl butyrate added, and the amount added is 0.5 to 3.0 with respect to the electrolytic solution.
It has been found that it is necessary to set the weight percent. Furthermore, by setting the addition amount of the above methyl butyrate to 0.5 to 2.0% by weight, not only the rise of the battery surface temperature during overcharge can be suppressed but also the capacity recovery rate after storage can be improved. It turns out that
【００６０】次に、添加剤として酢酸ブチル或いは酢酸
ブチルと酪酸メチルの混合物を用いた場合について、苛
酷な条件下での使用における安全性を検討した。Next, in the case of using butyl acetate or a mixture of butyl acetate and methyl butyrate as an additive, the safety in use under severe conditions was examined.
【００６１】実施例４ 上記実施例１において電解液に添加する添加成分として
用いた酪酸メチルを酢酸ブチルに変え、該酢酸ブチルの
割合を電解液に対して０．５重量％とし、その他は上記
実施例１と同様にして円筒型電池を作製した。そして、
得られた円筒型電池について、上述と同様の条件で電池
容量、過充電試験時の電池表面温度及び高温保存による
電池容量への影響を調べた。 Example 4 Methyl butyrate used as an additive component added to the electrolytic solution in Example 1 was changed to butyl acetate, and the ratio of the butyl acetate was 0.5% by weight with respect to the electrolytic solution. A cylindrical battery was produced in the same manner as in Example 1. And
With respect to the obtained cylindrical battery, the influences on the battery capacity, the battery surface temperature during the overcharge test and the high temperature storage on the battery capacity were examined under the same conditions as above.
【００６２】実施例５ 上記実施例４において電解液に添加した酢酸ブチルの割
合を１．０重量％に変え、その他は上記実施例４と同様
にして円筒型電池を作製した。そして、得られた円筒型
電池について、上述と同様の条件で電池容量、過充電試
験時の電池表面温度及び高温保存による電池容量への影
響を調べた。 Example 5 A cylindrical battery was manufactured in the same manner as in Example 4 except that the proportion of butyl acetate added to the electrolytic solution in Example 4 was changed to 1.0% by weight. Then, with respect to the obtained cylindrical battery, the influences on the battery capacity, the battery surface temperature during the overcharge test, and the high temperature storage on the battery capacity were examined under the same conditions as described above.
【００６３】実施例６ 上記実施例４において電解液に添加した酢酸ブチルの割
合を３．０重量％に変え、その他は上記実施例４と同様
にして円筒型電池を作製した。そして、得られた円筒型
電池について、上述と同様の条件で電池容量、過充電試
験時の電池表面温度及び高温保存による電池容量への影
響を調べた。 Example 6 A cylindrical battery was manufactured in the same manner as in Example 4 except that the proportion of butyl acetate added to the electrolytic solution in Example 4 was changed to 3.0% by weight. Then, with respect to the obtained cylindrical battery, the influences on the battery capacity, the battery surface temperature during the overcharge test, and the high temperature storage on the battery capacity were examined under the same conditions as described above.
【００６４】実施例７ 上記実施例１において電解液に添加する添加成分として
用いた酪酸メチルを酢酸ブチルと酪酸メチルの混合物
（重量比１：１）に変え、該混合物の割合を電解液に対
して１．０重量％とし、その他は上記実施例１と同様に
して円筒型電池を作製した。 Example 7 The methyl butyrate used as the additive component added to the electrolytic solution in the above Example 1 was changed to a mixture of butyl acetate and methyl butyrate (weight ratio 1: 1), and the ratio of the mixture to the electrolytic solution was changed. To 1.0% by weight, and otherwise the same as in Example 1 above to manufacture a cylindrical battery.
【００６５】そして、得られた円筒型電池について、上
述と同様の条件で電池容量、過充電試験時の電池表面温
度及び高温保存による電池容量への影響を調べた。Then, with respect to the obtained cylindrical battery, the influence on the battery capacity, the battery surface temperature at the time of the overcharge test, and the effect of the high temperature storage on the battery capacity was examined under the same conditions as described above.
【００６６】比較例３ 上記実施例４において電解液に添加した酢酸ブチルの割
合を５．０重量％に変え、その他は上記実施例４と同様
にして円筒型電池を作製した。そして、得られた円筒型
電池について、上述と同様の条件で電池容量、過充電試
験時の電池表面温度及び高温保存による電池容量への影
響を調べた。 Comparative Example 3 A cylindrical battery was manufactured in the same manner as in Example 4 except that the ratio of butyl acetate added to the electrolytic solution in Example 4 was changed to 5.0% by weight. Then, with respect to the obtained cylindrical battery, the influences on the battery capacity, the battery surface temperature during the overcharge test, and the high temperature storage on the battery capacity were examined under the same conditions as described above.
【００６７】下記の表２に、各実施例４〜７及び比較例
３において作製した電池の初期容量、過充電中における
電池表面温度の最高値及び高温保存後の容量回復率をそ
れぞれ示した。Table 2 below shows the initial capacity of the batteries prepared in Examples 4 to 7 and Comparative Example 3, the maximum value of the battery surface temperature during overcharge, and the capacity recovery rate after high temperature storage.
【００６８】[0068]
【表２】 [Table 2]
【００６９】表２に示すように、電解液に酢酸ブチルを
添加した実施例４〜６及び比較例３では、添加成分を加
えなかった電解液を使用した場合（比較例１）に比べ
て、過充電中における電池表面温度の最高値が低く抑え
られており、良好な安全性が得られることが判った。ま
た、上記実施例４〜６及び比較例３の結果から、電解液
に酢酸ブチルを添加しても、容量に対する悪影響は見ら
れなかった。As shown in Table 2, in Examples 4 to 6 in which butyl acetate was added to the electrolytic solution and Comparative Example 3, as compared with the case where the electrolytic solution containing no additional component was used (Comparative Example 1), It was found that the maximum value of the battery surface temperature during overcharging was kept low, and good safety was obtained. Further, from the results of Examples 4 to 6 and Comparative Example 3 above, no adverse effect on the capacity was observed even when butyl acetate was added to the electrolytic solution.
【００７０】更に、高温保存後の容量回復率は、酢酸ブ
チルの添加量が少ない電池では、添加成分を加えていな
い電解液を使用した電池よりもやや高い値を示したが、
添加量が増加するにつれて、若干低下する傾向が見ら
れ、酢酸ブチルを５．０重量％添加した比較例３では、
容量回復率が８０％を下回ってしまった。Further, the capacity recovery rate after storage at high temperature was slightly higher in the battery containing less butyl acetate than in the battery using the electrolyte solution containing no additional component.
A slight decrease was observed as the amount of addition increased. In Comparative Example 3 in which 5.0% by weight of butyl acetate was added,
The capacity recovery rate has fallen below 80%.
【００７１】このことから、酢酸ブチルの添加量には最
適値が存在し、添加量は電解液に対して０．５〜３．０
重量％とすることが必要であることが判った。更に、上
記酢酸ブチルの添加量を０．５〜２．０重量％とするこ
とにより、過充電中における電池表面温度の上昇を抑え
ることができるだけでなく、保存後の容量回復率を向上
させることができることが判った。From this, the optimum amount of butyl acetate exists, and the addition amount is 0.5 to 3.0 with respect to the electrolytic solution.
It has been found that it is necessary to set the weight percent. Furthermore, by adjusting the amount of butyl acetate added to 0.5 to 2.0% by weight, not only the increase in battery surface temperature during overcharging can be suppressed, but also the capacity recovery rate after storage can be improved. It turns out that
【００７２】一方、実施例７のように電解液に酢酸ブチ
ルと酪酸メチルの混合物を添加することによっても、過
充電中における電池表面温度の最高値が低く抑えられ
た。また、電解液に対する上記混合物の添加量が１重量
％である場合には、容量や高温保存後の容量回復率に対
する悪影響は見られなかった。On the other hand, by adding a mixture of butyl acetate and methyl butyrate to the electrolytic solution as in Example 7, the maximum value of the battery surface temperature during overcharge was suppressed to a low value. Further, when the amount of the above mixture added to the electrolytic solution was 1% by weight, no adverse effect was observed on the capacity and the capacity recovery rate after high temperature storage.
【００７３】従って、酢酸ブチル、酪酸メチルをそれぞ
れ単独で添加する方法だけでなく、両者を混合したもの
を添加することによっても同様の効果が得られた。但
し、この場合、混合物としての添加量の合計が電解液に
対して０．５〜３．０重量％、好ましくは０．５〜２．
０重量％であることが必要である。Therefore, the same effect was obtained not only by adding butyl acetate and methyl butyrate alone, but also by adding a mixture of both. However, in this case, the total amount of addition as a mixture is 0.5 to 3.0% by weight, preferably 0.5 to 2.
It is necessary to be 0% by weight.
【００７４】なお、本実施例では、電池の形状は円筒型
で説明を行ったが、これに限定されるものではなく、例
えば角型、コイン型、ボタン型等であっても同様の効果
を得ることができる。In the present embodiment, the shape of the battery is described as a cylindrical shape, but the shape is not limited to this. For example, a rectangular shape, a coin shape, a button shape, or the like can be used to obtain the same effect. Obtainable.
【００７５】[0075]
【発明の効果】以上の説明からも明らかなように、本発
明においては、炭素材料を負極活物質の担持体とするリ
チウムイオン二次電池において、電解液中に添加成分と
して酪酸メチル、酢酸ブチルを単独、若しくは両者の混
合物を微量添加しているので、確率的には非常に低い場
合ではあるが、例えば機器の故障や誤使用により上限電
圧の設定が無効になり、電池が過充電領域まで充電され
るような事態が発生した場合でも、異常反応が抑えら
れ、電池温度の上昇が抑制される。As is apparent from the above description, in the present invention, in a lithium ion secondary battery using a carbon material as a support for a negative electrode active material, methyl butyrate and butyl acetate are added components in the electrolytic solution. Since it is added singly or a small amount of a mixture of both, stochastic is very low, but the setting of the upper limit voltage becomes invalid due to equipment failure or misuse, for example, and the battery is overcharged. Even if the battery is charged, the abnormal reaction is suppressed and the battery temperature rise is suppressed.
【００７６】従って、本発明によれば、高容量で保存性
に優れ、且つ機器の故障や誤使用等の不慮の事態に際し
ても、より安全性の高い電池を得ることができる。Therefore, according to the present invention, it is possible to obtain a battery having a high capacity, excellent storability, and higher safety even in the unlikely event of a device failure or misuse.
【図１】本発明の非水電解液二次電池の一構成例を示す
断面図である。FIG. 1 is a cross-sectional view showing a configuration example of a non-aqueous electrolyte secondary battery of the present invention.
１ 負極 ２ 正極 ３ セパレータ ４ 絶縁板 ５ 電池缶 ６ 封口ガスケット ７ 電池蓋 ８ 安全弁装置 ９ ＰＴＣ素子 １０ 負極集電体 １１ 正極集電体 １２ 負極リード １３ 正極リード １４ センターピン 1 Negative electrode 2 Positive electrode 3 Separator 4 Insulating plate 5 Battery can 6 Sealing gasket 7 Battery lid 8 Safety valve device 9 PTC element 10 Negative electrode current collector 11 Positive electrode current collector 12 Negative electrode lead 13 Positive electrode lead 14 Center pin
Claims (3)
質材料を負極活物質とする負極と、リチウムと遷移金属
との複合酸化物を正極活物質とする正極と、非水電解液
とを具備してなる非水電解液二次電池において、 上記非水電解液に酪酸メチルが０．５〜３重量％の割合
で添加されることを特徴とする非水電解液二次電池。1. A negative electrode using a carbonaceous material capable of doping and dedoping lithium as a negative electrode active material, a positive electrode using a composite oxide of lithium and a transition metal as a positive electrode active material, and a non-aqueous electrolyte. In the non-aqueous electrolyte secondary battery, the non-aqueous electrolyte secondary battery is characterized in that methyl butyrate is added to the non-aqueous electrolyte in a proportion of 0.5 to 3% by weight.
質材料を負極活物質とする負極と、リチウムと遷移金属
との複合酸化物を正極活物質とする正極と、非水電解液
とを具備してなる非水電解液二次電池において、 上記非水電解液に酢酸ブチルが０．５〜３重量％の割合
で添加されることを特徴とする非水電解液二次電池。2. A negative electrode using a carbonaceous material capable of doping and dedoping lithium as a negative electrode active material, a positive electrode using a composite oxide of lithium and a transition metal as a positive electrode active material, and a non-aqueous electrolytic solution. A non-aqueous electrolyte secondary battery in which butyl acetate is added to the above-mentioned non-aqueous electrolyte in a proportion of 0.5 to 3% by weight.
質材料を負極活物質とする負極と、リチウムと遷移金属
との複合酸化物を正極活物質とする正極と、非水電解液
とを具備してなる非水電解液二次電池において、 上記非水電解液に酪酸メチルと酢酸ブチルの混合物が
０．５〜３重量％の割合で添加されることを特徴とする
非水電解液二次電池。3. A negative electrode using a carbonaceous material capable of doping or dedoping lithium as a negative electrode active material, a positive electrode using a composite oxide of lithium and a transition metal as a positive electrode active material, and a non-aqueous electrolyte solution. In the non-aqueous electrolyte secondary battery, the non-aqueous electrolyte secondary battery is characterized in that a mixture of methyl butyrate and butyl acetate is added to the non-aqueous electrolyte in a proportion of 0.5 to 3% by weight. battery.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6112783A JPH07320777A (en) | 1994-05-26 | 1994-05-26 | Nonaqueous electrolytic secondary battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6112783A JPH07320777A (en) | 1994-05-26 | 1994-05-26 | Nonaqueous electrolytic secondary battery |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07320777A true JPH07320777A (en) | 1995-12-08 |
Family
ID=14595397
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6112783A Withdrawn JPH07320777A (en) | 1994-05-26 | 1994-05-26 | Nonaqueous electrolytic secondary battery |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07320777A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2251926A1 (en) * | 2008-03-13 | 2010-11-17 | Ube Industries, Ltd. | Non-aqueous electrolyte for a lithium battery, lithium battery wherein said electrolyte is used, and hydroxy-acid derivative for use in said electrolyte |
| JP2011526726A (en) * | 2008-06-30 | 2011-10-13 | エルジー・ケム・リミテッド | Cylindrical lithium secondary battery |
-
1994
- 1994-05-26 JP JP6112783A patent/JPH07320777A/en not_active Withdrawn
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2251926A1 (en) * | 2008-03-13 | 2010-11-17 | Ube Industries, Ltd. | Non-aqueous electrolyte for a lithium battery, lithium battery wherein said electrolyte is used, and hydroxy-acid derivative for use in said electrolyte |
| EP2251926A4 (en) * | 2008-03-13 | 2012-12-05 | Ube Industries | Non-aqueous electrolyte for a lithium battery, lithium battery wherein said electrolyte is used, and hydroxy-acid derivative for use in said electrolyte |
| US8580429B2 (en) | 2008-03-13 | 2013-11-12 | Ube Industries, Ltd. | Non-aqueous electrolyte for a lithium battery, lithium battery wherein said electrolyte is used, and hydroxy-acid derivative for use in said electrolyte |
| JP2011526726A (en) * | 2008-06-30 | 2011-10-13 | エルジー・ケム・リミテッド | Cylindrical lithium secondary battery |
| US8936880B2 (en) | 2008-06-30 | 2015-01-20 | Lg Chem, Ltd. | Cylindrical lithium secondary battery with pressure activated current interruptive device |
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