JP3179459B2 - Non-aqueous electrolyte secondary battery - Google Patents
Non-aqueous electrolyte secondary batteryInfo
- Publication number
- JP3179459B2 JP3179459B2 JP22843089A JP22843089A JP3179459B2 JP 3179459 B2 JP3179459 B2 JP 3179459B2 JP 22843089 A JP22843089 A JP 22843089A JP 22843089 A JP22843089 A JP 22843089A JP 3179459 B2 JP3179459 B2 JP 3179459B2
- Authority
- JP
- Japan
- Prior art keywords
- secondary battery
- negative electrode
- aqueous electrolyte
- electrolyte secondary
- battery
- 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
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、炭素質材料を負極に用いた非水電解液二次
電池の改良に関するものである。Description: TECHNICAL FIELD The present invention relates to an improvement of a non-aqueous electrolyte secondary battery using a carbonaceous material for a negative electrode.
負極に炭素質材料を用いた非水電解液二次電池におい
て、前記炭素質材料として、Ｘ線回折におけるＣ軸方向
の結晶厚みLcが73Å〜85Åの範囲の炭素質材料を用いる
ことによって、充放電サイクル特性に優れ、放電容量が
大きく、その上自己放電率を低減した非水電解液二次電
池を提供する。In a non-aqueous electrolyte secondary battery using a carbonaceous material for the negative electrode, the carbonaceous material is filled by using a carbonaceous material having a crystal thickness Lc in the C-axis direction in X-ray diffraction in the range of 73 ° to 85 °. Provided is a non-aqueous electrolyte secondary battery having excellent discharge cycle characteristics, a large discharge capacity, and a reduced self-discharge rate.
近年、ビデオカメラやラジオカセットコーダー等のポ
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。現在使用されている二次電池の殆どは、
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、この電池の電圧は約1.2Vと低いので、電池
のエネルギー密度を向上させることは困難である。ま
た、この電池は常温での自己放電率が１ケ月で20％以上
という欠点もある。そこで、負極にリチウム等の軽金属
を使用し、また電解液に非水溶媒を使用することによっ
て、電圧が3V以上と高く、しかも自己放電率も低い二次
電池が検討された。2. Description of the Related Art In recent years, with the spread of portable devices such as a video camera and a radio cassette coder, a demand for a secondary battery that can be used repeatedly instead of a disposable primary battery is increasing. Most of the secondary batteries currently used are
This is a nickel-cadmium battery using an alkaline electrolyte. However, since the voltage of this battery is as low as about 1.2 V, it is difficult to improve the energy density of the battery. This battery also has a disadvantage that the self-discharge rate at room temperature is 20% or more in one month. Therefore, a secondary battery having a high voltage of 3 V or more and a low self-discharge rate by using a light metal such as lithium for the negative electrode and a non-aqueous solvent for the electrolytic solution has been studied.
しかし、このような二次電池では、負極に使用するリ
チウム等が充放電の繰り返しによってデンドライト状に
成長し、この負極と正極が接触して電池が内部で短絡す
るという不都合が生じ易かった。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二次
電池が検討された。しかし、この電池も、負極の合金が
充放電の進行につれて崩壊し易く、実用化が困難であ
る。そこで、例えば特開昭62−90863号公報に示されて
いるように、コークス等の炭素質材料を負極として使用
する二次電池が提案された。この提案によって、上述し
たような、充放電の繰り返しにおける負極の劣化問題を
回避できることが判った。ここで、炭素質材料は、アル
カリ金属イオンの、電解液を通してのドーピング、脱ド
ーピングによって二次電池の負極として作用するとされ
ている。このように、充放電サイクル特性に優れた炭素
質材料を負極とした二次電池は、しかしながら、金属リ
チウム等を負極とした電池に比べ、自己放電率が極めて
高く、そのために実用化に至っていないのが現状であ
る。However, in such a secondary battery, lithium or the like used for the negative electrode grows in a dendrite shape due to repetition of charge and discharge, and the disadvantage that the negative electrode and the positive electrode come into contact and the battery is short-circuited easily occurs easily. For this reason, a secondary battery in which lithium or the like is alloyed with another metal and this alloy is used for the negative electrode has been studied. However, in this battery as well, the alloy of the negative electrode is liable to collapse as charging and discharging progress, and it is difficult to put the battery to practical use. Accordingly, a secondary battery using a carbonaceous material such as coke as a negative electrode has been proposed as disclosed in, for example, JP-A-62-90863. It has been found that this proposal makes it possible to avoid the problem of deterioration of the negative electrode due to repeated charging and discharging as described above. Here, the carbonaceous material is said to function as a negative electrode of a secondary battery by doping and undoping of an alkali metal ion through an electrolytic solution. As described above, a secondary battery using a carbonaceous material having excellent charge / discharge cycle characteristics as a negative electrode, however, has a very high self-discharge rate as compared with a battery using a negative electrode such as metallic lithium or the like, and thus has not been put to practical use. is the current situation.
本発明の課題は、上述した現状に鑑み、負極に炭素質
材料を用いた非水電解液二次電池の問題点である高い自
己放電率を低減することである。An object of the present invention is to reduce a high self-discharge rate which is a problem of a non-aqueous electrolyte secondary battery using a carbonaceous material for a negative electrode in view of the above-described current situation.
［課題を解決するための手段］ 本発明は、コークスを熱処理してなる炭素質材料を有
する負極と、リチウム塩を電解質として非水溶媒に溶解
した非水電解液とを有する非水電解液二次電池であっ
て、前記の炭素質材料としてＸ線回折におけるＣ軸方向
の結晶厚みLc（以下、単にLcと記す）73Å〜85Åの範囲
の炭素質材料を使用する。Means for Solving the Problems The present invention provides a non-aqueous electrolyte comprising a negative electrode having a carbonaceous material obtained by heat-treating coke, and a non-aqueous electrolyte obtained by dissolving a lithium salt as an electrolyte in a non-aqueous solvent. In a secondary battery, a carbonaceous material having a crystal thickness Lc in the C-axis direction in X-ray diffraction (hereinafter simply referred to as Lc) of 73 ° to 85 ° is used as the carbonaceous material.
Lcが小さいと自己放電が大きくなり、逆にLcが大きい
と放電容量が小さくなる傾向があり、この両者の兼ね合
いから、Lcは73Å〜85Åの範囲であることが好ましい。
Lcが小さいことは、あまり黒鉛化が進んでいないことを
意味し、そのような状態では不純物を含みやすく、その
ために自己放電が大きくなると考えられる。また逆にLc
が大きいことは、黒鉛化が進んでいることを意味し、そ
のような状態では、リチウムイオンがドープ、脱ドープ
しにくくなり、そのために放電容量が小さくなると考え
られる。本発明に用いられる正極材料としては、一般に
リチウム二次電池に用いられる、例えば二酸化マンガ
ン、五酸化バナジウムにような遷移金属化合物や、硫化
鉄等の遷移金属カルコゲン化合物等が使用可能である。
電解液としては、リチウム塩を電解質といて、非水溶媒
に溶解した非水電解液が使用可能である。ここで非水溶
媒としては、特に限定されるものではないが、例えばプ
ロピレンカーボネート、エチレンカーボネート、1.2−
ジメトキシエタン、1.2−ジエトキシエタン、γ−ブチ
ロラクトン、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、ジエチルエーテ
ル、スルホラン、メチルスルホラン、アセトニトリル、
プロピオニトリル等の単独もしくは２種以上の混合溶媒
が使用できる。電解質も従来より公知のものがいずれも
使用可能であり、LiClO4、LiAsF6、LiPF6、LiBF4、LiB
（C6H5）４、LiCl、LiBr、CH3SO3Li、CF3SO3Li等があ
る。When Lc is small, self-discharge increases, and when Lc is large, discharge capacity tends to decrease. Lc is preferably in the range of 73 ° to 85 ° in consideration of both.
A small Lc means that the graphitization has not progressed much, and it is considered that in such a state, impurities are likely to be contained and self-discharge is increased. Lc
Means that graphitization is progressing, and in such a state, lithium ions are less likely to be doped or undoped, and thus it is considered that the discharge capacity is reduced. As the positive electrode material used in the present invention, for example, transition metal compounds such as manganese dioxide and vanadium pentoxide, and transition metal chalcogen compounds such as iron sulfide, which are generally used in lithium secondary batteries, can be used.
As the electrolyte, a non-aqueous electrolyte obtained by dissolving a lithium salt as an electrolyte in a non-aqueous solvent can be used. Here, the non-aqueous solvent is not particularly limited, for example, propylene carbonate, ethylene carbonate, 1.2-
Dimethoxyethane, 1.2-diethoxyethane, γ-butyrolactone, tetrahydrofuran, 1.3-dioxolan, 4-methyl-1.3-dioxolan, diethyl ether, sulfolane, methylsulfolane, acetonitrile,
A single solvent such as propionitrile or a mixture of two or more solvents can be used. As the electrolyte, any of those conventionally known can be used, and LiClO 4 , LiAsF 6 , LiPF 6 , LiBF 4 , LiB
(C 6 H 5 ) 4 , LiCl, LiBr, CH 3 SO 3 Li, CF 3 SO 3 Li and the like.
負極に炭素質材料を用いる非水電解液二次電池におい
て、前記炭素質材料のLcを73Å〜85Åの範囲に選ぶこと
によって、放電容量をあまり低下させることなく、自己
放電率を著しく低減できる。In a non-aqueous electrolyte secondary battery using a carbonaceous material for the negative electrode, by selecting Lc of the carbonaceous material in the range of 73 ° to 85 °, the self-discharge rate can be significantly reduced without significantly reducing the discharge capacity.
第１図は、本発明の実施例で適用された円筒型非水電
解液二次電池の構造を模式的に示す断面図である。この
電池は、第１図で示されるように、正極１と負極２がセ
パレータ３を介して渦巻状に巻かれた電極構造をもつ渦
巻式円筒型非水電解液二次電池である。以下、実施例を
第１図を参照しながら説明する。FIG. 1 is a sectional view schematically showing a structure of a cylindrical nonaqueous electrolyte secondary battery applied in an embodiment of the present invention. As shown in FIG. 1, this battery is a spiral cylindrical non-aqueous electrolyte secondary battery having an electrode structure in which a positive electrode 1 and a negative electrode 2 are spirally wound via a separator 3. Hereinafter, an embodiment will be described with reference to FIG.
実施例１ まず、負極２は次のように作製した。粉砕したニード
ルコークスをアルゴン雰囲気の電気炉中1500℃で２時間
処理してLcが73Åのものを作り、これを負極材料として
用いた。Example 1 First, the negative electrode 2 was produced as follows. The pulverized needle coke was treated in an electric furnace under an argon atmosphere at 1500 ° C. for 2 hours to produce a coke having an Lc of 73 °, which was used as a negative electrode material.
なお、ここでLcはＸ線回折で、002回折線図形から日
本学術振興会法に準じて求められた（以下の全ての実施
例及び比較例においても同様な方法でLcは求められ
た）。Here, Lc was X-ray diffraction, which was determined from the 002 diffraction line pattern according to the method of the Japan Society for the Promotion of Science (Lc was also determined by the same method in all the following Examples and Comparative Examples).
この高温処理したニードルコークスの真密度は2.16g/
cm3、Ｘ線回折における002面の面間隔はd002（以下、単
にd002と記す）は3.44Åであった。このニードルコーク
ス90重量部に結着剤としてのポリフッ化ビニリデン10重
量部を加え、混合し、負極合剤とした。そしてこの負極
合剤を溶剤Ｎ−メチルピロリドンに分散させてスラリー
（ペースト状）にした。次に、この負極合剤スラリー
を、負極集電体としての厚さ10μｍの銅箔の両面に塗布
し、乾燥した。乾燥後にローラープレス機により圧縮成
形して、これを34.5mmの幅にカットして帯状の負極２を
作った。The true density of this high temperature treated needle coke is 2.16 g /
cm 3 , and the plane spacing between the 002 planes in X-ray diffraction was d002 (hereinafter simply referred to as d002) was 3.44 °. To 90 parts by weight of this needle coke, 10 parts by weight of polyvinylidene fluoride as a binder were added and mixed to obtain a negative electrode mixture. The negative electrode mixture was dispersed in a solvent N-methylpyrrolidone to form a slurry (paste). Next, this negative electrode mixture slurry was applied to both surfaces of a 10 μm-thick copper foil as a negative electrode current collector, and dried. After drying, it was compression-molded by a roller press, and cut into a width of 34.5 mm to form a strip-shaped negative electrode 2.
この帯状の負極２において、負極合剤は負極集電体の
両面に互いにほぼ同じ膜厚で形成してあり、これらの膜
厚の和は約175μｍであった。In the strip-shaped negative electrode 2, the negative electrode mixture was formed on both surfaces of the negative electrode current collector with substantially the same film thickness, and the sum of these film thicknesses was about 175 μm.
次に正極１は次のようにして作製した。 Next, the positive electrode 1 was produced as follows.
炭酸リチウム１モルと炭酸コバルトを混合し、900℃
の空気中で５時間焼成してLiCoO2を得、これを正極活物
質として用い、このLiCoO291重量部に導電材としてグラ
ファイト６重量部、結着剤としてポリフッ化ビニリデン
３重量部を加え、混合して正極合剤とした。そして、こ
の正極合剤を溶剤Ｎ−メチルピロリドンに分散させてス
ラリー（ペースト状）にした。次い、この正極合剤スラ
リーを、正極集電体としての厚さ20μｍの帯状のアルミ
ニウム箔の両面に塗布し、乾燥した。乾燥後にローラー
プレス機により圧縮成形して、これを33.5mmの幅にカッ
トして帯状の正極１を作った。この帯状の正極１におい
て、正極合剤は正極集電体の両面に互いにほぼ同じ膜厚
で形成してあり、これらの膜厚の和は約175μｍであっ
た。そして、帯状の正極１、帯状の負極２及び厚さ25μ
ｍの微孔性ポリプロピレンフィルムからなるセパレータ
３を、負極２、セパレータ３、正極１、セパレータ３の
順序で積層してから、この積層体を渦巻状に多数回巻回
することによって、巻回体を作製した。Mix 1 mol of lithium carbonate and cobalt carbonate, 900 ℃
Baking in air for 5 hours to obtain LiCoO 2 , using this as a positive electrode active material, adding 6 parts by weight of graphite as a conductive material and 3 parts by weight of polyvinylidene fluoride as a binder to 91 parts by weight of LiCoO 2 , The mixture was mixed to form a positive electrode mixture. Then, this positive electrode mixture was dispersed in a solvent N-methylpyrrolidone to form a slurry (paste). Next, this positive electrode mixture slurry was applied to both sides of a 20 μm-thick strip-shaped aluminum foil as a positive electrode current collector, and dried. After drying, it was compression-molded by a roller press, and cut into a width of 33.5 mm to form a belt-shaped positive electrode 1. In this strip-shaped positive electrode 1, the positive electrode mixture was formed on both surfaces of the positive electrode current collector to have substantially the same film thickness, and the sum of these film thicknesses was about 175 μm. Then, a strip-shaped positive electrode 1, a strip-shaped negative electrode 2 and a thickness of 25 μm
m, the separator 3 made of a microporous polypropylene film is laminated in the order of the negative electrode 2, the separator 3, the positive electrode 1, and the separator 3, and then the laminate is spirally wound many times to obtain a wound body. Was prepared.
上述のようにして作った巻回体を、第１図に示すよう
に、ニッケルめっきを施した内径13.8mmの鉄製電池缶に
収納した。そして、正極１の集電を行うために、アルミ
ニウム製の正極リード８を正極１を取付け、これを正極
１から導出して、電池蓋７に溶接した。また、負極２の
集電を行うために、ニッケル製の負極リード９を負極２
に取付け、これを負極２から導出して、電池缶５に溶接
した。この電池缶の中に、六フッ化リン酸リチウムを１
モル／リットルの濃度で溶解した炭酸プロピレンと1.2
−ジメトキシエタンとを混合して得た電解液を注入し
た。次に、巻回体の上下面に対向するように、電池缶５
内に絶縁板４を配設した。また、この電池缶５と電池蓋
７を絶縁封口ガスケット６を介してかしめて、電池蓋７
を封口した。以上のようにして直径13.8mm、高さ42mmの
円筒型非水電解液二次電池を作製した。The wound body produced as described above was housed in a nickel-plated iron battery can having an inner diameter of 13.8 mm, as shown in FIG. Then, in order to collect the current of the positive electrode 1, a positive electrode lead 8 made of aluminum was attached to the positive electrode 1, which was led out from the positive electrode 1 and welded to the battery lid 7. In order to collect the current of the negative electrode 2, a negative electrode lead 9 made of nickel is connected to the negative electrode 2.
, Which was led out of the negative electrode 2 and welded to the battery can 5. One lithium hexafluorophosphate is placed in this battery can.
Propylene carbonate dissolved in a concentration of 1.2 mol / l and 1.2
-An electrolyte obtained by mixing with dimethoxyethane was injected. Next, the battery can 5 is opposed to the upper and lower surfaces of the wound body.
An insulating plate 4 was provided therein. Further, the battery can 5 and the battery cover 7 are caulked via an insulating sealing gasket 6 to
Was sealed. As described above, a cylindrical nonaqueous electrolyte secondary battery having a diameter of 13.8 mm and a height of 42 mm was produced.
実施例２ 粉砕したニードルコークスをアルゴン雰囲気の電気炉
中1600℃で２時間処理して、Lcが85Åのものを作り、こ
れを負極材料として用いた。この高温処理したニードル
コークスの真密度は2.17g/cm3、d002は3.43Åであっ
た。そして、これ以外は実施例１と同様にして電池を作
製した。Example 2 Pulverized needle coke was treated in an electric furnace in an argon atmosphere at 1600 ° C. for 2 hours to produce a product having an Lc of 85 ° and used as a negative electrode material. The true density of the needle coke subjected to the high temperature treatment was 2.17 g / cm 3 , and d002 was 3.43 °. Except for this, a battery was manufactured in the same manner as in Example 1.
比較例１ 粉砕したニードルコークスを熱処理せずそのまま負極
材料として用いた。このニードルコークスのLcは59Å、
真密度は2.12g/cm3、d002は3.44Åであった。そして、
それ以外は実施例１と同様にして電池を作製した。Comparative Example 1 Pulverized needle coke was used as a negative electrode material without heat treatment. Lc of this needle coke is 59Å,
The true density was 2.12 g / cm 3 and d002 was 3.443.4. And
Otherwise, the procedure of Example 1 was followed to fabricate a battery.
比較例２ 粉砕したニードルコークスをアルゴン雰囲気の電気炉
中1200℃で２時間処理して、Lcが60Åのものを作り、こ
れを負極材料として用いた。この高温処理したニードル
コークスの真密度は2.12g/cm3、d002は3.44Åであっ
た。そして、これ以外は実施例と同様にして電池を作製
した。Comparative Example 2 Pulverized needle coke was treated in an electric furnace in an argon atmosphere at 1200 ° C. for 2 hours to produce a coke having an Lc of 60 °, which was used as a negative electrode material. The true density of the needle coke subjected to the high temperature treatment was 2.12 g / cm 3 , and d002 was 3.44 °. Except for this, a battery was manufactured in the same manner as in the example.
比較例３ 粉砕したニードルコークスをアルゴン雰囲気の電気炉
中1300℃で２時間処理して、Lcが63Åのものを作り、こ
れを負極材料として用いた。この高温処理したニードル
コークスの真密度は2.13g/cm3、d002は3.44Åであっ
た。そして、それ以外は実施例１と同様にして電池を作
製した。Comparative Example 3 Pulverized needle coke was treated in an electric furnace in an argon atmosphere at 1300 ° C. for 2 hours to produce a coke having an Lc of 63 °, which was used as a negative electrode material. The true density of the needle coke subjected to the high temperature treatment was 2.13 g / cm 3 , and d002 was 3.44 °. Otherwise, a battery was fabricated in the same manner as in Example 1.
比較例４ 粉砕したニードルコークスをアルゴン雰囲気の電気炉
中1400℃で２時間処理して、Lcが65Åのものを作り、こ
れを負極材料として用いた。この高温処理したニードル
コークスの真密度は2.15g/cm3、d002は3.44Åであっ
た。そして、それ以外は実施例１と同様にして電池を作
製した。Comparative Example 4 Pulverized needle coke was treated at 1400 ° C. for 2 hours in an electric furnace in an argon atmosphere to produce a product having an Lc of 65 ° and used as a negative electrode material. The true density of the needle coke subjected to the high temperature treatment was 2.15 g / cm 3 , and d002 was 3.44 °. Otherwise, a battery was fabricated in the same manner as in Example 1.
比較例５ 粉砕したニードルコークスをアルゴン雰囲気の電気炉
中1700℃で２時間処理して、Lcが98Åのものを作り、こ
れを負極材料として用いた。この高温処理したニードル
コークスの真密度は2.17g/cm3、d002は3.42Åであっ
た。そして、それ以外は実施例１と同様にして電池を作
製した。Comparative Example 5 Pulverized needle coke was treated at 1700 ° C. for 2 hours in an electric furnace in an argon atmosphere to produce a coke having an Lc of 98 °, which was used as a negative electrode material. The true density of this high temperature treated needle coke was 2.17 g / cm 3 , and d002 was 3.42 °. Otherwise, a battery was fabricated in the same manner as in Example 1.
実施例及び比較例で示した電池を何れも充電電流190m
Aで上限電圧4.1Vとして３時間定電流充電を行い、次に1
6オームで終止電圧2.9Vまで放電を行う充放電サイクル
を20回行い、20回目の放電容量を測定した。次に、再び
これらの電池を前述の充電条件で充電した後、電池を24
℃の温度の下で720時間放置し、その後に放電試験を行
い、この放電容量も測定し、20回目の放電容量と比較し
て自己放電率を算出した。以上の測定の結果を第１表に
示す。またこの結果を第２図のグラフに示す。Each of the batteries shown in Examples and Comparative Examples had a charging current of 190 m.
A constant current charging for 3 hours with an upper limit voltage of 4.1 V at A
Twenty charge / discharge cycles were performed to discharge to a final voltage of 2.9 V at 6 ohms, and the twentieth discharge capacity was measured. Next, after charging these batteries again under the charging conditions described above,
After leaving for 720 hours at a temperature of ° C., a discharge test was performed, the discharge capacity was also measured, and the self-discharge rate was calculated in comparison with the discharge capacity at the 20th time. Table 1 shows the results of the above measurements. The results are shown in the graph of FIG.
第１表からLcの小さいニードルコークスの方が放電容
量が大きく、Lcが85Å以下で320mA以上の放電容量が得
られ、Lcが85Å以上では放電容量が急に小さくなる傾向
が見られる。また、Lcが大きい程、自己放電率が低くな
り、Lcが73Å以上では６％以下の低自己放電率が得られ
るが、Lcが73Åより小さいと自己放電率は急に高くなる
傾向が見られる。このように、自己放電と放電容量の両
方を考え合わせると、Lcが73Å〜85Åの範囲にあるニー
ドルコークスについての結果を示したが、ピッチコーク
スについても同様な結果が得られた。 From Table 1, it can be seen that the discharge capacity of the needle coke having a smaller Lc is larger, the discharge capacity of 320 mA or more is obtained when Lc is 85 ° or less, and the discharge capacity suddenly decreases when the Lc is 85 ° or more. Also, as Lc is larger, the self-discharge rate is lower. When Lc is 73 ° or more, a low self-discharge rate of 6% or less is obtained, but when Lc is less than 73 °, the self-discharge rate tends to suddenly increase. . Thus, when considering both self-discharge and discharge capacity, the results were shown for needle coke with Lc in the range of 73 ° to 85 °, but similar results were obtained for pitch coke.
本発明により、コークス等の炭素質材料を負極に用い
る非水電解液二次電池の従来よりの欠点であった、自己
放電が大きいという問題を解決することができた。これ
により、高エネルギー密度でサイクル特性に優れ、その
上保存性に優れた二次電池を提供できるようになり、そ
の工業的価値は大である。According to the present invention, the problem of a large self-discharge, which has been a disadvantage of the conventional nonaqueous electrolyte secondary battery using a carbonaceous material such as coke for the negative electrode, can be solved. As a result, a secondary battery having high energy density, excellent cycle characteristics, and excellent storage stability can be provided, and its industrial value is great.
第１図は本発明の実施例で適用した円筒型非水電解液二
次電池の構造を模式的に示す断面図、第２図は炭素質材
料のLcと自己放電率および放電容量（720時間放電後）
の関係を示すグラフである。 図の中で用いた符号において、 １……正極 ２……負極 ３……セパレータFIG. 1 is a cross-sectional view schematically showing the structure of a cylindrical non-aqueous electrolyte secondary battery applied in an embodiment of the present invention, and FIG. 2 is a graph showing Lc of the carbonaceous material, self-discharge rate and discharge capacity (720 hours). After discharge)
6 is a graph showing the relationship of. In the reference numerals used in the figures, 1... Positive electrode 2... Negative electrode 3.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭62−122066（ＪＰ，Ａ) 特開 昭62−90863（ＪＰ，Ａ) 特開 平３−53450（ＪＰ，Ａ) 特開 昭62−272472（ＪＰ，Ａ) 特開 昭61−66365（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) H01M 4/38,10/40 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-122066 (JP, A) JP-A-62-90863 (JP, A) JP-A-3-53450 (JP, A) JP-A 62-122450 272472 (JP, A) JP-A-61-66365 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) H01M 4/38, 10/40
Claims (3)
する負極と、リチウム塩を電解質として非水溶媒に溶解
した非水電解液とを有する非水電解液二次電池におい
て、 前記炭素質材料のＸ線回折におけるＣ軸方向の結晶厚み
Lcが73Å以上85Å以下の範囲にあることを特徴とする非
水電解液二次電池。1. A non-aqueous electrolyte secondary battery comprising: a negative electrode having a carbonaceous material obtained by heat-treating coke; and a non-aqueous electrolyte having a lithium salt as an electrolyte dissolved in a non-aqueous solvent. Crystal thickness in the C-axis direction in X-ray diffraction of
A nonaqueous electrolyte secondary battery, wherein Lc is in the range of 73 ° to 85 °.
電体の両面に炭素質材料を形成した負極と、正極集電体
の両面にリチウム複合酸化物を形成した正極とをセパレ
ータを介して渦巻状に多数回巻回された渦巻式電極と、
リチウム塩を電解質として非水溶媒に溶解した非水電解
液とを有する非水電解液二次電池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。2. The non-aqueous electrolyte secondary battery comprises a negative electrode having a carbonaceous material formed on both sides of a strip-shaped negative electrode current collector and a positive electrode having lithium composite oxide formed on both sides of a positive electrode current collector. A spiral electrode wound spirally many times via a separator,
The non-aqueous electrolyte secondary battery according to claim 1, wherein the non-aqueous electrolyte secondary battery includes a non-aqueous electrolyte in which a lithium salt is dissolved as an electrolyte in a non-aqueous solvent.
びピッチコークスのいずれか一種の熱処理生成物である
ことを特徴とする請求項１又は２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 is a heat treatment product of one of needle coke and pitch coke.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22843089A JP3179459B2 (en) | 1989-09-05 | 1989-09-05 | Non-aqueous electrolyte secondary battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22843089A JP3179459B2 (en) | 1989-09-05 | 1989-09-05 | Non-aqueous electrolyte secondary battery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0393162A JPH0393162A (en) | 1991-04-18 |
| JP3179459B2 true JP3179459B2 (en) | 2001-06-25 |
Family
ID=16876363
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22843089A Expired - Fee Related JP3179459B2 (en) | 1989-09-05 | 1989-09-05 | Non-aqueous electrolyte secondary battery |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3179459B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014121505A (en) * | 2012-12-21 | 2014-07-03 | Kokusai Shoji Co Ltd | Finger-ring rice paddle |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3311402B2 (en) * | 1992-11-19 | 2002-08-05 | 三洋電機株式会社 | Rechargeable battery |
-
1989
- 1989-09-05 JP JP22843089A patent/JP3179459B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014121505A (en) * | 2012-12-21 | 2014-07-03 | Kokusai Shoji Co Ltd | Finger-ring rice paddle |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0393162A (en) | 1991-04-18 |
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