JPH04289658A - Nonaqueous electrolyte secondary battery - Google Patents
Nonaqueous electrolyte secondary batteryInfo
- Publication number
- JPH04289658A JPH04289658A JP3054526A JP5452691A JPH04289658A JP H04289658 A JPH04289658 A JP H04289658A JP 3054526 A JP3054526 A JP 3054526A JP 5452691 A JP5452691 A JP 5452691A JP H04289658 A JPH04289658 A JP H04289658A
- Authority
- JP
- Japan
- Prior art keywords
- positive electrode
- electrolyte secondary
- secondary battery
- fibrous graphite
- graphite
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000011255 nonaqueous electrolyte Substances 0.000 title claims abstract description 23
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 47
- 229910002804 graphite Inorganic materials 0.000 claims abstract description 41
- 239000010439 graphite Substances 0.000 claims abstract description 41
- 238000007599 discharging Methods 0.000 claims abstract description 16
- 238000007600 charging Methods 0.000 claims abstract description 15
- 239000000835 fiber Substances 0.000 claims description 14
- 229910003002 lithium salt Inorganic materials 0.000 claims description 3
- 159000000002 lithium salts Chemical class 0.000 claims description 3
- 230000002441 reversible effect Effects 0.000 claims description 3
- 229910052744 lithium Inorganic materials 0.000 abstract description 7
- 229910032387 LiCoO2 Inorganic materials 0.000 abstract description 4
- 239000011149 active material Substances 0.000 abstract description 3
- 239000006258 conductive agent Substances 0.000 description 19
- 230000014759 maintenance of location Effects 0.000 description 16
- 239000007774 positive electrode material Substances 0.000 description 15
- 230000007423 decrease Effects 0.000 description 7
- 230000000694 effects Effects 0.000 description 7
- 239000000203 mixture Substances 0.000 description 7
- -1 polytetrafluoroethylene Polymers 0.000 description 7
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 6
- 239000006230 acetylene black Substances 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- 239000003792 electrolyte Substances 0.000 description 5
- 239000004743 Polypropylene Substances 0.000 description 4
- MHCFAGZWMAWTNR-UHFFFAOYSA-M lithium perchlorate Chemical compound [Li+].[O-]Cl(=O)(=O)=O MHCFAGZWMAWTNR-UHFFFAOYSA-M 0.000 description 4
- 229910001486 lithium perchlorate Inorganic materials 0.000 description 4
- 229920001155 polypropylene Polymers 0.000 description 4
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 description 4
- 229910002097 Lithium manganese(III,IV) oxide Inorganic materials 0.000 description 3
- 239000011230 binding agent Substances 0.000 description 3
- 238000007789 sealing Methods 0.000 description 3
- YEJRWHAVMIAJKC-UHFFFAOYSA-N 4-Butyrolactone Chemical compound O=C1CCCO1 YEJRWHAVMIAJKC-UHFFFAOYSA-N 0.000 description 2
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 2
- 229910003092 TiS2 Inorganic materials 0.000 description 2
- 238000010277 constant-current charging Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 239000002657 fibrous material Substances 0.000 description 2
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 2
- 239000004810 polytetrafluoroethylene Substances 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- XTHFKEDIFFGKHM-UHFFFAOYSA-N Dimethoxyethane Chemical compound COCCOC XTHFKEDIFFGKHM-UHFFFAOYSA-N 0.000 description 1
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 1
- 229910014143 LiMn2 Inorganic materials 0.000 description 1
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 1
- XBDQKXXYIPTUBI-UHFFFAOYSA-M Propionate Chemical compound CCC([O-])=O XBDQKXXYIPTUBI-UHFFFAOYSA-M 0.000 description 1
- KXKVLQRXCPHEJC-UHFFFAOYSA-N acetic acid trimethyl ester Natural products COC(C)=O KXKVLQRXCPHEJC-UHFFFAOYSA-N 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 238000009831 deintercalation Methods 0.000 description 1
- 238000003795 desorption Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 150000002170 ethers Chemical class 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 230000002687 intercalation Effects 0.000 description 1
- 238000009830 intercalation Methods 0.000 description 1
- 150000002642 lithium compounds Chemical class 0.000 description 1
- 229910001416 lithium ion Inorganic materials 0.000 description 1
- MCVFFRWZNYZUIJ-UHFFFAOYSA-M lithium;trifluoromethanesulfonate Chemical compound [Li+].[O-]S(=O)(=O)C(F)(F)F MCVFFRWZNYZUIJ-UHFFFAOYSA-M 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 1
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、非水電解液二次電池に
関し、特に正極を改良した非水電解液二次電池に関する
。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolyte secondary battery, and more particularly to a non-aqueous electrolyte secondary battery with an improved positive electrode.
【０００２】0002
【従来の技術】リチウムまたはリチウム化合物を負極と
する非水電解液二次電池は高電圧で高エネルギー密度と
なることが期待され、多くの研究が行なわれている。BACKGROUND OF THE INVENTION Non-aqueous electrolyte secondary batteries using lithium or lithium compounds as negative electrodes are expected to have high voltage and high energy density, and many studies are being conducted.
【０００３】特に、これら電池の正極活物質としてＭｎ
Ｏ２やＴｉＳ２がよく検討されている。これらの正極活
物質はＬｉに対する電位が３Ｖ程度であるが、さらに最
近、ＬｉＭｎＯ２Ｏ４およびＬｉＣｏＯ２がＬｉに対し
て４Ｖ以上の電位を示す正極活物質として注目されてい
る。In particular, Mn is used as the positive electrode active material of these batteries.
O2 and TiS2 are often considered. These positive electrode active materials have a potential of about 3 V with respect to Li, but more recently, LiMnO2O4 and LiCoO2 have attracted attention as positive electrode active materials exhibiting a potential of 4 V or more with respect to Li.
【０００４】すなわち、電池の高エネルギー密度を得る
手段として容量の拡大とともに電池電圧を高める努力が
なされている。That is, efforts are being made to increase the battery voltage as well as expand the capacity as a means of obtaining a high energy density of the battery.
【０００５】上記の正極活物質を用いた非水電解液二次
電池の課題の１つに充放電にともなう容量低下がある。
このサイクル特性を向上するために、これまでに正極活
物質の改良や電解液の検討，セパレータの改善などの多
くの努力がなされている。[0005] One of the problems with non-aqueous electrolyte secondary batteries using the above-mentioned positive electrode active material is a decrease in capacity due to charging and discharging. In order to improve this cycle characteristic, many efforts have been made so far, such as improving positive electrode active materials, examining electrolytes, and improving separators.
【０００６】[0006]
【発明が解決しようとする課題】このような充放電を繰
り返した場合の放電容量の低下が起こる原因の１つとし
ては、上記の正極活物質などのリチウムを挿入，脱離す
ることのできる化合物においても、深い充放電を繰り返
すと活物質の微細化が起こり、その結果、電極が崩れて
しまうことが考えられる。そこで、正極にフッ素樹脂，
ポリオレフィンなどの結着材が用いられている。しかし
ながら、この場合においてもリチウムの挿入，脱離に伴
う電極の膨張，収縮の結果、活物質保持の不良や集電不
良が生じ充分なサイクル特性が得られないという欠点を
有している。[Problems to be Solved by the Invention] One of the reasons why the discharge capacity decreases when charging and discharging are repeated is that compounds that can intercalate and deintercalate lithium, such as the above-mentioned positive electrode active materials, Even in this case, repeated deep charging and discharging may cause the active material to become finer, and as a result, the electrode may collapse. Therefore, we used fluororesin as the positive electrode.
A binder such as polyolefin is used. However, even in this case, as a result of the expansion and contraction of the electrode due to the intercalation and deintercalation of lithium, there is a drawback that insufficient active material retention and current collection occur, making it impossible to obtain sufficient cycle characteristics.
【０００７】本発明は上記のような充放電に伴う放電容
量の低下、すなわち、サイクル特性が不十分であるとい
う問題を解決し、充放電サイクル特性に優れた非水電解
液二次電池を提供することを目的とする。[0007] The present invention solves the above problem of a decrease in discharge capacity due to charging and discharging, that is, insufficient cycle characteristics, and provides a non-aqueous electrolyte secondary battery with excellent charge and discharge cycle characteristics. The purpose is to
【０００８】[0008]
【課題を解決するための手段】この課題を解決するため
本発明の非水電解液二次電池は、充電放電に対し可逆性
を有する正極と負極と、リチウム塩を含有する非水電解
液とを有し、前記正極中に繊維状黒鉛を含むものである
。[Means for Solving the Problem] In order to solve this problem, the non-aqueous electrolyte secondary battery of the present invention includes a positive electrode and a negative electrode that are reversible in charging and discharging, and a non-aqueous electrolyte containing a lithium salt. The positive electrode contains fibrous graphite.
【０００９】また繊維状黒鉛の添加量は０．５重量％〜
２０重量％であることが望ましい。さらに、繊維状黒鉛
の平均繊維径に対する平均繊維長の比は１０〜５００が
好ましい。[0009] The amount of fibrous graphite added is 0.5% by weight or more.
The content is preferably 20% by weight. Furthermore, the ratio of the average fiber length to the average fiber diameter of the fibrous graphite is preferably 10 to 500.
【００１０】0010
【作用】この構成により本発明の非水電解液二次電池は
、正極中に導電剤として繊維状黒鉛を添加することによ
り、電極の膨張時においても充分な集電が得られる。
その結果、少ないサイクル数で充放電容量が低下するこ
とがなくなることとなる。[Function] With this structure, the non-aqueous electrolyte secondary battery of the present invention can obtain sufficient current collection even when the electrode is expanded by adding fibrous graphite as a conductive agent to the positive electrode. As a result, the charge/discharge capacity does not decrease even with a small number of cycles.
【００１１】[0011]
【実施例】以下、本発明の一実施例の非水電解液二次電
池について図面を基にして説明する。DESCRIPTION OF THE PREFERRED EMBODIMENTS A non-aqueous electrolyte secondary battery according to an embodiment of the present invention will be described below with reference to the drawings.
【００１２】（実施例１）電池の製造を次のようにして
行なう。(Example 1) A battery was manufactured as follows.
【００１３】正極中の導電剤として繊維径と繊維長さの
比率が１：２０（アスペクト比２０）、１：７５（アス
ペクト比７５）、１：２００（アスペクト比２００）の
３種類の繊維状黒鉛を用いて構成したものについて説明
する。なお、用いた繊維状黒鉛の平均繊維径はすべて０
．１μｍである。Three types of fibrous materials are used as the conductive agent in the positive electrode, with the ratio of fiber diameter to fiber length being 1:20 (aspect ratio 20), 1:75 (aspect ratio 75), and 1:200 (aspect ratio 200). A device constructed using graphite will be explained. The average fiber diameter of the fibrous graphite used was all 0.
．． It is 1 μm.
【００１４】正極活物質としてＬｉＣｏＯ２ １００
ｇに導電剤として上記繊維状黒鉛３．０ｇを混合し、さ
らに、結着剤としてのポリ４弗化エチレン樹脂５．０ｇ
を混合して正極合剤とした。正極合剤０．１グラムを直
径１７．５ｍｍに１トン／ｃｍ２でプレス成型して、正
極とした。図１において、成型した正極１をケース２に
置く。
正極１の上にセパレータ３としての多孔性ポリプロピレ
ンフィルムを置いた。負極４として直径１７．５ｍｍ，
厚さ０．３ｍｍのリチウム板を、ポリプロピレン製ガス
ケット５を付けた封口板６に圧着した。非水電解液とし
て、１モル／ｌの過塩素酸リチウムを溶解したプロピレ
ンカーボネート溶液を用い、これをセパレータ３上およ
び負極４上に加えた。その後電池を封口した。上記のよ
うにして得られた電池の充放電サイクル試験を行なった
。[0014] LiCoO2 100 as a positive electrode active material
3.0 g of the above-mentioned fibrous graphite as a conductive agent was mixed with g, and 5.0 g of polytetrafluoroethylene resin was added as a binder.
were mixed to form a positive electrode mixture. 0.1 g of the positive electrode mixture was press-molded into a diameter of 17.5 mm at 1 ton/cm 2 to obtain a positive electrode. In FIG. 1, a molded positive electrode 1 is placed in a case 2. A porous polypropylene film as a separator 3 was placed on the positive electrode 1 . As the negative electrode 4, the diameter is 17.5 mm,
A lithium plate with a thickness of 0.3 mm was crimped onto a sealing plate 6 to which a polypropylene gasket 5 was attached. A propylene carbonate solution in which 1 mol/l of lithium perchlorate was dissolved was used as the non-aqueous electrolyte, and this was added onto the separator 3 and the negative electrode 4. After that, the battery was sealed. The battery obtained as described above was subjected to a charge/discharge cycle test.
【００１５】なお比較例として、導電剤として繊維状黒
鉛ではなく従来のアセチレンブラックを添加した正極を
用いた電池も上記と同様の方法で作製した。As a comparative example, a battery using a positive electrode containing conventional acetylene black instead of fibrous graphite as a conductive agent was also fabricated in the same manner as above.
【００１６】以上のように導電剤の異なる４種類の電池
の充放電サイクル特性の比較を行なった。なお本実施例
における充放電サイクル試験は、充放電電流０．５ｍＡ
，電圧範囲が４．２Ｖから３．０Ｖの間で定電流充放電
することで行なった。As described above, the charge/discharge cycle characteristics of four types of batteries using different conductive agents were compared. Note that the charge/discharge cycle test in this example was conducted at a charge/discharge current of 0.5 mA.
This was carried out by constant current charging and discharging within a voltage range of 4.2V to 3.0V.
【００１７】（表１）に初期放電容量ならびに初期放電
容量に対する１００サイクル目の放電容量の容量維持率
を示す。サンプル数ｎはそれぞれ５０個とした。Table 1 shows the initial discharge capacity and the capacity retention ratio of the discharge capacity at the 100th cycle with respect to the initial discharge capacity. The number of samples n was 50 for each.
【００１８】ここでの放電容量は正極活物質１ｇ当りに
換算している。The discharge capacity here is calculated per 1 g of positive electrode active material.
【００１９】[0019]
【表１】[Table 1]
【００２０】（表１）に示すように、導電剤として従来
のアセチレンブラックを添加した正極を用いた比較例の
電池は、１００サイクル後の放電容量維持率が７０％程
度まで低下する。一方、導電剤として繊維状黒鉛を含む
正極を用いた本実施例の電池はいずれも従来例の電池と
比較して放電容量が大きく向上し、また１００サイクル
後の放電容量維持率が９０％以上とサイクル特性も大幅
に向上している。このような電池の放電容量の向上は、
導電剤としてアセチレンブラックを添加した場合には正
極中の電子伝導性が小さく、すなわち集電がまだ不十分
であったものが、導電剤として繊維状黒鉛を含有させる
ことで充分な集電が得られるようになったためと考えら
れる。また、正極中に繊維状黒鉛を含有させることで充
放電時の電極の膨張においても充分な集電が得られる。
その結果、少ないサイクル数で充放電容量が低下するこ
とがなくなると考えられる。As shown in Table 1, in the battery of the comparative example using the positive electrode to which conventional acetylene black was added as a conductive agent, the discharge capacity retention rate after 100 cycles decreased to about 70%. On the other hand, all of the batteries of this example using positive electrodes containing fibrous graphite as a conductive agent have greatly improved discharge capacity compared to conventional batteries, and have a discharge capacity retention rate of 90% or more after 100 cycles. The cycle characteristics have also been significantly improved. This improvement in battery discharge capacity is due to
When acetylene black was added as a conductive agent, the electron conductivity in the positive electrode was low, meaning that current collection was still insufficient, but by adding fibrous graphite as a conductive agent, sufficient current collection was achieved. This is thought to be due to the fact that it has become possible to Further, by including fibrous graphite in the positive electrode, sufficient current collection can be obtained even when the electrode expands during charging and discharging. As a result, it is thought that the charge/discharge capacity does not decrease with a small number of cycles.
【００２１】さらに、アスペクト比の異なる繊維状黒鉛
を導電剤として含有した場合について着目すると、アス
ペクト比２０の繊維状黒鉛を用いた場合、１００サイク
ル目での容量維持率は９０％であり、充放電サイクル特
性の向上効果がみられた。また、アスペクト比７５と２
００の場合にも、１００サイクル目での容量維持率はそ
れぞれ９３％，９６％と同等な効果が得られた。[0021] Furthermore, focusing on the case where fibrous graphite with different aspect ratios is contained as a conductive agent, when fibrous graphite with an aspect ratio of 20 is used, the capacity retention rate at the 100th cycle is 90%. The effect of improving discharge cycle characteristics was observed. Also, the aspect ratio is 75 and 2.
Even in the case of 00, the capacity retention rate at the 100th cycle was 93% and 96%, respectively, and the same effect was obtained.
【００２２】（実施例２）次に、正極活物質としてＬｉ
Ｍｎ２Ｏ４を用いて実施例１と同様の検討を行なった。(Example 2) Next, Li was used as the positive electrode active material.
The same study as in Example 1 was conducted using Mn2O4.
【００２３】正極中の導電剤として繊維径と繊維長さの
比率が１：２０（アスペクト比２０）、１：７５（アス
ペクト比７５）、１：２００（アスペクト比２００）の
３種類の繊維状黒鉛を用いて構成した。なお、用いた繊
維状黒鉛の平均繊維径はすべて０．１μｍである。Three types of fibrous materials are used as the conductive agent in the positive electrode, with ratios of fiber diameter and fiber length of 1:20 (aspect ratio 20), 1:75 (aspect ratio 75), and 1:200 (aspect ratio 200). Constructed using graphite. Note that the average fiber diameter of the fibrous graphite used was all 0.1 μm.
【００２４】正極活物質としてＬｉＭｎ２Ｏ４ １０
０ｇに導電剤として上記繊維状黒鉛３．０ｇを混合し、
さらに、結着剤としてのポリ４弗化エチレン樹脂５．０
ｇを混合して正極合剤とした。正極合剤０．１グラムを
直径１７．５ｍｍに１トン／ｃｍ２でプレス成型して、
正極とした。図１において、成型した正極１をケース２
に置く。
正極１の上にセパレータ３としての多孔性ポリプロピレ
ンフィルムを置いた。負極４として直径１７．５ｍｍ，
厚さ０．３ｍｍのリチウム板を、ポリプロピレン製ガス
ケット５を付けた封口板６に圧着した。非水電解液とし
て、１モル／ｌの過塩素酸リチウムを溶解したプロピレ
ンカーボネート溶液を用い、これをセパレータ３上およ
び負極４上に加えた。その後電池を封口した。上記のよ
うにして得られた電池の充放電サイクル試験を行なった
。LiMn2O4 10 as a positive electrode active material
0g and 3.0g of the above fibrous graphite as a conductive agent mixed,
Furthermore, polytetrafluoroethylene resin 5.0 as a binder
g was mixed to prepare a positive electrode mixture. 0.1 g of the positive electrode mixture was press-molded into a diameter of 17.5 mm at 1 ton/cm2.
It was used as a positive electrode. In Figure 1, the molded positive electrode 1 is placed in a case 2.
put it on. A porous polypropylene film as a separator 3 was placed on the positive electrode 1 . As the negative electrode 4, the diameter is 17.5 mm,
A lithium plate with a thickness of 0.3 mm was crimped onto a sealing plate 6 to which a polypropylene gasket 5 was attached. A propylene carbonate solution in which 1 mol/l of lithium perchlorate was dissolved was used as the non-aqueous electrolyte, and this was added onto the separator 3 and the negative electrode 4. After that, the battery was sealed. The battery obtained as described above was subjected to a charge/discharge cycle test.
【００２５】なお比較例として、導電剤として繊維状黒
鉛ではなく従来のアセチレンブラックを添加した正極を
用いた電池も上記と同様の方法で作製した。As a comparative example, a battery using a positive electrode to which conventional acetylene black was added instead of fibrous graphite as a conductive agent was also fabricated in the same manner as above.
【００２６】以上のように導電剤の異なる４種類の電池
の充放電サイクル特性の比較を行なった。なお本実施例
における充放電サイクル試験は、充放電電流０．５ｍＡ
、電圧範囲が４．３Ｖから３．０Ｖの間で定電流充放電
することで行なった。As described above, the charge/discharge cycle characteristics of four types of batteries using different conductive agents were compared. Note that the charge/discharge cycle test in this example was conducted at a charge/discharge current of 0.5 mA.
This was carried out by constant current charging and discharging within a voltage range of 4.3V to 3.0V.
【００２７】（表２）に初期放電容量ならびに初期放電
容量に対する１００サイクル目の放電容量の容量維持率
を示す。サンプル数ｎはそれぞれ５０個とした。Table 2 shows the initial discharge capacity and the capacity retention ratio of the discharge capacity at the 100th cycle with respect to the initial discharge capacity. The number of samples n was 50 for each.
【００２８】ここでの放電容量は正極活物質１ｇ当りに
換算している。The discharge capacity here is calculated per 1 g of positive electrode active material.
【００２９】[0029]
【表２】[Table 2]
【００３０】（表２）に示すように、導電剤として従来
のアセチレンブラックを添加した正極を用いた比較例の
電池は、１００サイクル後の放電容量維持率が６０％程
度まで低下する。一方、導電剤として繊維状黒鉛を含む
正極を用いた本実施例の電池はいずれも比較例の電池と
比較し放電容量が大きく向上し、また１００サイクル後
の放電容量維持率が８５％以上とサイクル特性も大幅に
向上している。このように正極活物質としてＬｉＭｎ２
Ｏ４を用いた場合にも、正極中に繊維状黒鉛を含有させ
ることで充放電時の電極の膨張においても充分な集電が
得られる。その結果、少ないサイクル数で充放電容量が
低下することがなくなると考えられる。As shown in Table 2, in the battery of the comparative example using the positive electrode to which conventional acetylene black was added as a conductive agent, the discharge capacity retention rate after 100 cycles decreased to about 60%. On the other hand, all of the batteries of this example using positive electrodes containing fibrous graphite as a conductive agent had greatly improved discharge capacity compared to the batteries of comparative examples, and the discharge capacity retention rate after 100 cycles was 85% or more. Cycle characteristics have also been significantly improved. In this way, LiMn2 is used as a positive electrode active material.
Even when O4 is used, sufficient current collection can be obtained by including fibrous graphite in the positive electrode even when the electrode expands during charging and discharging. As a result, it is thought that the charge/discharge capacity does not decrease with a small number of cycles.
【００３１】さらに、アスペクト比の異なる繊維状黒鉛
を導電剤として含有した場合について着目すると、アス
ペクト比２０の繊維状黒鉛を用いた場合、１００サイク
ル目での容量維持率は８９％であり、充放電サイクル特
性の向上効果がみられた。また、アスペクト比７５と２
００の場合にも、１００サイクル目での容量維持率はそ
れぞれ９３％，９８％と同等な効果が得られた。Furthermore, focusing on the case where fibrous graphite with different aspect ratios is contained as a conductive agent, when fibrous graphite with an aspect ratio of 20 is used, the capacity retention rate at the 100th cycle is 89%, and the charging The effect of improving discharge cycle characteristics was observed. Also, the aspect ratio is 75 and 2.
Even in the case of 00, the capacity retention rate at the 100th cycle was 93% and 98%, respectively, and the same effect was obtained.
【００３２】（実施例３）さらに、正極への繊維状黒鉛
の添加量について検討した。(Example 3) Furthermore, the amount of fibrous graphite added to the positive electrode was investigated.
【００３３】正極活物質としては、ＬｉＭｎ２Ｏ４を用
いた。正極中の導電剤として繊維径と繊維長さの比率が
、１：７５（アスペクト比７５）の繊維状黒鉛を用いて
構成したものについて説明する。[0033] LiMn2O4 was used as the positive electrode active material. An example will be described in which fibrous graphite with a fiber diameter to fiber length ratio of 1:75 (aspect ratio 75) is used as the conductive agent in the positive electrode.
【００３４】本実施例での正極合剤および電池構成方法
は実施例２と同様に行なった。（表３）に繊維状黒鉛の
添加量（電極中の含有量）とこれらの正極を用いた電池
の充放電サイクル試験での初期容量および１００サイク
ルにおける容量維持率を示す。The positive electrode mixture and battery construction method in this example were the same as in Example 2. (Table 3) shows the amount of fibrous graphite added (content in the electrode), the initial capacity in a charge/discharge cycle test of batteries using these positive electrodes, and the capacity retention rate in 100 cycles.
【００３５】[0035]
【表３】[Table 3]
【００３６】結果から正極への繊維状黒鉛の添加量が０
．５ｗｔ％より少ない場合には初期放電容量が小さく、
充放電に伴う容量維持率も低い。一方、繊維状黒鉛の添
加量が２０ｗｔ％より大きな場合には充放電に伴う容量
維持率は高いが初期放電容量が小さいものとなる。From the results, the amount of fibrous graphite added to the positive electrode is 0.
．． If it is less than 5wt%, the initial discharge capacity is small;
The capacity retention rate associated with charging and discharging is also low. On the other hand, if the amount of fibrous graphite added is greater than 20 wt%, the capacity retention rate during charging and discharging will be high, but the initial discharge capacity will be small.
【００３７】したがって、正極への繊維状黒鉛の添加量
は、０．５〜２０ｗｔ％の範囲が望ましい。[0037] Therefore, the amount of fibrous graphite added to the positive electrode is preferably in the range of 0.5 to 20 wt%.
【００３８】（実施例４）さらに、繊維状黒鉛の平均繊
維径に対する平均繊維長の比（アスペクト比）について
詳しく検討した。検討したアスペクト比は５，１０，２
０，５０，７５，１５０，２００，３００，５００，６
００，１０００の１１種類とした。(Example 4) Furthermore, the ratio of the average fiber length to the average fiber diameter (aspect ratio) of fibrous graphite was studied in detail. The aspect ratios considered were 5, 10, and 2.
0, 50, 75, 150, 200, 300, 500, 6
There were 11 types of 00,1000.
【００３９】正極活物質としては、ＬｉＣｏＯ２を用い
た。正極中への繊維状黒鉛の添加量は２．０重量％とし
て構成したものについて説明する。[0039] LiCoO2 was used as the positive electrode active material. In the following description, the amount of fibrous graphite added to the positive electrode is 2.0% by weight.
【００４０】本実施例での正極合剤および電池構成方法
は実施例１と同様に行なった。（表４）に繊維状黒鉛の
アスペクト比とこれらの正極を用いた電池の充放電サイ
クル試験での初期容量および１００サイクルにおける容
量維持率を示す。The positive electrode mixture and battery construction method in this example were the same as in Example 1. (Table 4) shows the aspect ratio of fibrous graphite, the initial capacity in a charge/discharge cycle test, and the capacity retention rate in 100 cycles of batteries using these positive electrodes.
【００４１】[0041]
【表４】[Table 4]
【００４２】結果から繊維状黒鉛のアスペクト比が１０
以上の場合に充放電に伴う容量維持率が高くなるが、ア
スペクト比が５００を越えると初期放電容量が小さいも
のとなる。From the results, the aspect ratio of fibrous graphite is 10.
In the above cases, the capacity retention rate accompanying charging and discharging becomes high, but when the aspect ratio exceeds 500, the initial discharge capacity becomes small.
【００４３】したがって、正極へ添加する繊維状黒鉛の
アスペクト比は、１０〜５００の範囲が望ましい。Therefore, the aspect ratio of the fibrous graphite added to the positive electrode is preferably in the range of 10 to 500.
【００４４】また、アセチレンブラックなどの導電材料
に比べて繊維状黒鉛はその形状からも理解できるように
、かさ密度が小さく電極合剤の密度を低下させ、単位体
積当りのエネルギー密度が小さくなる。このため、正極
へ含有する繊維状黒鉛のアスペクト比は、２０〜３００
の範囲がさらに好ましい。Furthermore, as can be understood from its shape, fibrous graphite has a smaller bulk density than conductive materials such as acetylene black, which lowers the density of the electrode mixture, resulting in a lower energy density per unit volume. Therefore, the aspect ratio of the fibrous graphite contained in the positive electrode is 20 to 300.
The range of is more preferable.
【００４５】以上の実施例では正極活物質としてＬｉＣ
ｏＯ２およびＬｉＭｎ２Ｏ４について説明したが、Ｍｎ
Ｏ２やＴｉＳ２を用いた場合にも同様の効果が認められ
ることを確認している。In the above examples, LiC was used as the positive electrode active material.
Although oO2 and LiMn2O4 were explained, Mn
It has been confirmed that similar effects are observed when O2 or TiS2 is used.
【００４６】これらの結果から、充放電時のリチウムイ
オンの挿入脱離反応による電極の膨張収縮が起こる正極
中に導電剤として繊維状黒鉛を添加することにより、電
極の膨張時においても充分な集電が得られる。From these results, it was found that by adding fibrous graphite as a conductive agent to the positive electrode, where the electrode expands and contracts due to lithium ion insertion/desorption reactions during charging and discharging, sufficient collection can be achieved even when the electrode expands. You can get electricity.
【００４７】その結果、比較的少ないサイクル数で充放
電容量が低下することがなくなり、安定した充放電サイ
クル特性を有する信頼性の高い非水電解液二次電池を得
ることができる。As a result, the charge/discharge capacity does not decrease even with a relatively small number of cycles, and a highly reliable non-aqueous electrolyte secondary battery having stable charge/discharge cycle characteristics can be obtained.
【００４８】なお、以上の実施例では、電解液として１
モル／ｌの過塩素酸リチウムを溶解したプロピレンカー
ボネート溶液を用いた場合の結果であるが、電解液とし
てこれ以外に、溶質として過塩素酸リチウム，６フッ化
燐酸リチウムやトリフロロメタンスルフォン酸リチウム
，ホウフッ化リチウム、溶媒としてプロピレンカーボネ
ート，エチレンカーボネートなどのカーボネート類、ガ
ンマーブチロラクトン，酢酸メチルなどのエステル類お
よびジメトキシエタンやテトラヒドロフランなどのエー
テル類を用いた電解液を用いた場合にも同様の効果が得
られることを確認した。[0048] In the above embodiments, the electrolyte was 1
These are the results when using a propylene carbonate solution containing mol/l of lithium perchlorate, but in addition to this, lithium perchlorate, lithium hexafluorophosphate, and lithium trifluoromethanesulfonate may be used as electrolytes as solutes. Similar effects can be obtained using electrolytes containing lithium borofluoride, carbonates such as propylene carbonate and ethylene carbonate, esters such as gamma-butyrolactone and methyl acetate, and ethers such as dimethoxyethane and tetrahydrofuran. I confirmed that I can get it.
【００４９】[0049]
【発明の効果】以上の実施例の説明で明らかなように本
発明の非水電解液二次電池によれば、充放電に対し可逆
性を有する正極と負極と、リチウム塩を含有する非水電
解液を主体とし、前記正極中に繊維状黒鉛を添加するこ
とにより、充放電サイクル特性が良好な非水電解液二次
電池を得ることができ、産業上の意義は大きい。Effects of the Invention As is clear from the above description of the embodiments, the non-aqueous electrolyte secondary battery of the present invention has a positive electrode and a negative electrode that are reversible in charging and discharging, and a non-aqueous electrolyte containing a lithium salt. By using an electrolyte as a main component and adding fibrous graphite to the positive electrode, a non-aqueous electrolyte secondary battery with good charge/discharge cycle characteristics can be obtained, which has great industrial significance.
【図１】本発明の一実施例の非水電解液二次電池の縦断
面図[Fig. 1] A vertical cross-sectional view of a non-aqueous electrolyte secondary battery according to an embodiment of the present invention.
１ 正極 ２ ケース ３ セパレータ ４ 負極 ５ ガスケット ６ 封口板 1 Positive electrode 2 Case 3 Separator 4 Negative electrode 5 Gasket 6 Sealing plate
Claims (3)
、リチウム塩を含有する非水電解液を主体とし、前記正
極中に繊維状黒鉛を含有する非水電解液二次電池。1. A non-aqueous electrolyte secondary battery comprising a positive electrode and a negative electrode that are reversible in charging and discharging, and a non-aqueous electrolyte containing a lithium salt, the positive electrode containing fibrous graphite.
長の比が１０〜５００である請求項１記載の非水電解液
二次電池。2. The nonaqueous electrolyte secondary battery according to claim 1, wherein the ratio of the average fiber length to the average fiber diameter of the fibrous graphite is 10 to 500.
０重量％である請求項１記載の非水電解液二次電池。Claim 3: The content of fibrous graphite in the positive electrode is 0.5 to 2.
The non-aqueous electrolyte secondary battery according to claim 1, wherein the content is 0% by weight.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3054526A JPH04289658A (en) | 1991-03-19 | 1991-03-19 | Nonaqueous electrolyte secondary battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3054526A JPH04289658A (en) | 1991-03-19 | 1991-03-19 | Nonaqueous electrolyte secondary battery |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04289658A true JPH04289658A (en) | 1992-10-14 |
Family
ID=12973107
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3054526A Pending JPH04289658A (en) | 1991-03-19 | 1991-03-19 | Nonaqueous electrolyte secondary battery |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04289658A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0856898A3 (en) * | 1997-02-04 | 1999-06-30 | Mitsubishi Denki Kabushiki Kaisha | Electrode for lithium ion secondary battery and lithium ion secondary battery using the same |
| JP2002507313A (en) * | 1997-06-27 | 2002-03-05 | エルジー・ケミカル・リミテッド | Lithium ion secondary battery and method of manufacturing the same |
| US6858349B1 (en) | 2000-09-07 | 2005-02-22 | The Gillette Company | Battery cathode |
| JP2010114042A (en) * | 2008-11-10 | 2010-05-20 | Nec Corp | Secondary battery, and manufacturing method thereof |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6358763A (en) * | 1986-08-28 | 1988-03-14 | Nikkiso Co Ltd | Graphite fiber-lithium secondary battery |
| JPS64645A (en) * | 1987-06-23 | 1989-01-05 | Yazaki Corp | Nonaqueous electrolyte secondary battery |
| JPH01143146A (en) * | 1987-11-27 | 1989-06-05 | Matsushita Electric Ind Co Ltd | Cell using manganese dioxide as active material |
| JPH0294363A (en) * | 1988-09-30 | 1990-04-05 | Furukawa Battery Co Ltd:The | Positive electrode for nonaqueous electrolyte secondary battery |
| JPH02262243A (en) * | 1989-03-31 | 1990-10-25 | Matsushita Electric Ind Co Ltd | Positive electrode for lithium secondary battery and manufacture thereof |
-
1991
- 1991-03-19 JP JP3054526A patent/JPH04289658A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6358763A (en) * | 1986-08-28 | 1988-03-14 | Nikkiso Co Ltd | Graphite fiber-lithium secondary battery |
| JPS64645A (en) * | 1987-06-23 | 1989-01-05 | Yazaki Corp | Nonaqueous electrolyte secondary battery |
| JPH01143146A (en) * | 1987-11-27 | 1989-06-05 | Matsushita Electric Ind Co Ltd | Cell using manganese dioxide as active material |
| JPH0294363A (en) * | 1988-09-30 | 1990-04-05 | Furukawa Battery Co Ltd:The | Positive electrode for nonaqueous electrolyte secondary battery |
| JPH02262243A (en) * | 1989-03-31 | 1990-10-25 | Matsushita Electric Ind Co Ltd | Positive electrode for lithium secondary battery and manufacture thereof |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0856898A3 (en) * | 1997-02-04 | 1999-06-30 | Mitsubishi Denki Kabushiki Kaisha | Electrode for lithium ion secondary battery and lithium ion secondary battery using the same |
| JP2002507313A (en) * | 1997-06-27 | 2002-03-05 | エルジー・ケミカル・リミテッド | Lithium ion secondary battery and method of manufacturing the same |
| US6858349B1 (en) | 2000-09-07 | 2005-02-22 | The Gillette Company | Battery cathode |
| JP2010114042A (en) * | 2008-11-10 | 2010-05-20 | Nec Corp | Secondary battery, and manufacturing method thereof |
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