JP2006269321A - Winding type non-aqueous electrolyte secondary battery - Google Patents
Winding type non-aqueous electrolyte secondary battery Download PDFInfo
- Publication number
- JP2006269321A JP2006269321A JP2005087851A JP2005087851A JP2006269321A JP 2006269321 A JP2006269321 A JP 2006269321A JP 2005087851 A JP2005087851 A JP 2005087851A JP 2005087851 A JP2005087851 A JP 2005087851A JP 2006269321 A JP2006269321 A JP 2006269321A
- Authority
- JP
- Japan
- Prior art keywords
- electrode plate
- ppm
- nmp
- secondary battery
- positive electrode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Landscapes
- Secondary Cells (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
Description
本発明は捲回型非水電解液二次電池における正極板または／および負極板に関する。 The present invention relates to a positive electrode plate and / or a negative electrode plate in a wound nonaqueous electrolyte secondary battery.
近年、電子機器のポータブル化、コードレス化が進んでおり、これらの駆動用電源として小型、軽量で高エネルギー密度を有する二次電池へと要望が強まっている。そのため、高電圧、高エネルギー密度を有する非水電解液二次電池、とりわけリチウム二次電池に対する期待が大きくなっている。正極活物質にはコバルト酸リチウム（以下、ＬｉＣｏＯ2と略す）が、負極活物質にはリチウムを可逆的にインターカレートできるグラファイトが一般的に用いられている。 In recent years, electronic devices have become portable and cordless, and there is an increasing demand for secondary batteries that are small, lightweight, and have high energy density as power sources for driving these devices. Therefore, expectation for non-aqueous electrolyte secondary batteries having high voltage and high energy density, particularly lithium secondary batteries, is increasing. Lithium cobaltate (hereinafter abbreviated as LiCoO 2 ) is generally used as the positive electrode active material, and graphite capable of reversibly intercalating lithium is used as the negative electrode active material.
このリチウム二次電池は、非水電解液中に正極板および負極板を配置した構造をしている。それら極板は、活物質と、導電材と、および結着剤が混合された合剤が、金属箔集電体表面に塗着されている。 This lithium secondary battery has a structure in which a positive electrode plate and a negative electrode plate are arranged in a non-aqueous electrolyte. In these electrode plates, a mixture in which an active material, a conductive material, and a binder are mixed is applied to the surface of the metal foil current collector.
リチウム二次電池用の正極板は以下のように作成するのが一般的である。結着剤としてポリフッ化ビニリデン（以下、ＰＶＤＦと略す）を予め溶解したＮ−メチルピロリドン（以下、ＮＭＰと略す）等の有機溶剤に、正極活物質と、炭素材料等の導電材を加え、混合し、合剤ペーストを作製する。この合剤ペーストを、集電体としてアルミニウム金属箔表面に塗着、乾燥し、正極板を作成する。また、負極板は一般的に以下のように作製する。正極板と同様に、結着剤としてＰＶＤＦを予め溶解したＮＭＰ等の有機溶剤に、負極活物質を加え、混合し、合剤ペーストを作製する。この合剤ペーストを、集電体として銅箔表面に塗着、乾燥し、負極板を作成する。そして、正極板と、負極板と、それら極板の間に介在させるセパレータとを、渦巻状に捲回し極板群を作製する。 A positive electrode plate for a lithium secondary battery is generally prepared as follows. A positive electrode active material and a conductive material such as a carbon material are added to and mixed with an organic solvent such as N-methylpyrrolidone (hereinafter abbreviated as NMP) in which polyvinylidene fluoride (hereinafter abbreviated as PVDF) is dissolved in advance as a binder. Then, a mixture paste is prepared. This mixture paste is applied to the surface of the aluminum metal foil as a current collector and dried to prepare a positive electrode plate. The negative electrode plate is generally produced as follows. Similarly to the positive electrode plate, a negative electrode active material is added to an organic solvent such as NMP in which PVDF is previously dissolved as a binder and mixed to prepare a mixture paste. This mixture paste is applied to the surface of the copper foil as a current collector and dried to prepare a negative electrode plate. Then, a positive electrode plate, a negative electrode plate, and a separator interposed between the electrode plates are wound in a spiral shape to produce an electrode plate group.
このように極板群を作製する時に、極板の表面にクラックが発生したり、合剤が集電体から剥離したりすることがある。この対策として、極板の柔軟性を向上させるために、極板の乾燥条件を制御することにより、極板中のＮＭＰ量を５０〜５００ｐｐｍと規定することが提案されている（例えば、特許文献１を参照）。
しかしながら、前述した従来の方法は、帯状に連続した幅広の状態における極板を乾燥する際の乾燥条件によって、極板中のＮＭＰ量を制御する方法である。この方法では、極板を帯状に連続した幅広の状態で乾燥するため、極板の幅方向における両端部と、幅方向における中央部とでは、残存ＮＭＰ量が異なる。その理由は以下の通りである。熱伝導により極板の幅方向における両端部のＮＭＰ量は少なくなる。しかし、極板の幅方向における中央部は、幅方向における両端部に比べ熱伝導が悪く、乾燥し難いため、ＮＭＰ量が多くなる。このように、極板の幅方向の部位によってＮＭＰ量が異なり、ＮＭＰ量が少ない部分の極板を用いた場合は、極板表面にクラックが発生し、合剤が集電体から剥離するという課題があった。 However, the above-described conventional method is a method of controlling the amount of NMP in the electrode plate according to the drying conditions when the electrode plate is dried in a wide state in a strip shape. In this method, since the electrode plate is dried in a wide continuous state in a strip shape, the remaining NMP amount is different between both end portions in the width direction of the electrode plate and the central portion in the width direction. The reason is as follows. The amount of NMP at both ends in the width direction of the electrode plate decreases due to heat conduction. However, the central portion in the width direction of the electrode plate is less thermally conductive than both end portions in the width direction and is difficult to dry, so the amount of NMP increases. Thus, the amount of NMP differs depending on the width direction of the electrode plate, and when the electrode plate with a small amount of NMP is used, cracks occur on the surface of the electrode plate, and the mixture is peeled from the current collector. There was a problem.
本発明はこのような従来の課題を解決するものであり、極板表面のクラックや、合剤と集電体との剥離を極力低減することができ、充放電サイクル特性が良好で、充放電サイクル後のインピーダンスも良好な捲回型非水電解液二次電池を提供するものである。 The present invention solves such a conventional problem, and can reduce cracks on the surface of the electrode plate and peeling between the mixture and the current collector as much as possible, has good charge / discharge cycle characteristics, and charge / discharge A wound non-aqueous electrolyte secondary battery having good impedance after cycling is provided.
前記従来の課題を解決するために、本発明の捲回型非水電解液二次電池において、正極板または／および負極板は、１０ｐｐｍ以上１００ｐｐｍ以下のＮ−メチルピロリドンを含んでいる。 In order to solve the above-described conventional problems, in the wound nonaqueous electrolyte secondary battery of the present invention, the positive electrode plate and / or the negative electrode plate contains 10 ppm to 100 ppm of N-methylpyrrolidone.
また、正極板または／および負極板は、曲率半径が２ｍｍ以下となる少なくとも巻き内側の部分に、１０ｐｐｍ以上１００ｐｐｍ以下のＮ−メチルピロリドンを含んでいる。 Moreover, the positive electrode plate and / or the negative electrode plate contain 10 ppm or more and 100 ppm or less of N-methylpyrrolidone at least at the inner part of the winding where the radius of curvature is 2 mm or less.
本発明によると、正極板または／および負極板は、１０ｐｐｍ以上１００ｐｐｍ以下のＮ−メチルピロリドンを含ませることにより、極板表面のクラックや、合剤と集電体との剥離を極力低減することができ、充放電サイクル特性が良好で、充放電サイクル後のインピーダンスも良好な捲回型非水電解液二次電池を提供することができる。 According to the present invention, the positive electrode plate and / or the negative electrode plate contain as much as 10 ppm or more and 100 ppm or less of N-methylpyrrolidone, thereby reducing cracks on the electrode plate surface and peeling between the mixture and the current collector as much as possible. It is possible to provide a wound non-aqueous electrolyte secondary battery having good charge / discharge cycle characteristics and good impedance after the charge / discharge cycle.
本発明の捲回型非水電解液二次電池は、正極板または／および負極板は、１０ｐｐｍ以上１００ｐｐｍ以下のＮ−メチルピロリドンを含んでいる。 In the wound nonaqueous electrolyte secondary battery of the present invention, the positive electrode plate and / or the negative electrode plate contains 10 ppm or more and 100 ppm or less of N-methylpyrrolidone.
こうすることにより、極板を渦巻き状に捲回して極板群を作製する際に、極板を折り曲げたり、引っ張ったりしても、極板表面にクラックが発生したり、合剤と集電体が剥離したり、最悪の場合は極板が破断したりすることなく、渦巻き状に捲回できるようになる。 In this way, when the electrode plate is wound into a spiral shape to produce a group of electrode plates, even if the electrode plate is bent or pulled, cracks may occur on the surface of the electrode plate, The body can be wound in a spiral without peeling off or, in the worst case, breaking of the electrode plate.
これは、極板のＮＭＰ量が１０ｐｐｍより少ない場合、結着剤のＰＶＤＦが硬化し、極板の柔軟性が低下する。逆に極板のＮＭＰ量が１００ｐｐｍよりも大きい場合、極板の柔軟性は確保できるが、ＮＭＰ量が多いため、ＮＭＰが非水電解液中に溶け出し、正極活物質と反応して非水電解液が変質し、サイクル特性等に悪影響を及ぼすこととなる。
本発明の別の実施形態において、正極板または／および負極板は、曲率半径が２ｍｍ以下となる少なくとも巻き内側の部分に、１０ｐｐｍ以上１００ｐｐｍ以下のＮ−メチルピロリドンを含んでいる。
これは、捲回型非水電解液二次電池の内、円筒型非水電解液二次電池の場合、極板群の内周部の曲率半径が最も小さくなる極板の部分にクラックが発生したり、合剤と集電体が剥離したりし易くなる。この極板の部分に、ＮＭＰ量が１０ｐｐｍ以上１００ｐｐｍ以下になるように含ませることにより、極板の柔軟性が向上し、クラックや剥離を防ぐことができる。また、角型非水電解液二次電池の場合、極板群を扁平型に捲回する際においても、曲率半径が最も小さくなる極板の部分にも、円筒型非水電解液二次電池の時と同様にＮＭＰ量が１０ｐｐｍ以上１００ｐｐｍ以下になるように含ませることにより、極板の柔軟性が向上し、クラックや剥離を防ぐことができる。
This is because when the amount of NMP in the electrode plate is less than 10 ppm, the PVDF as the binder is cured and the flexibility of the electrode plate is lowered. Conversely, when the NMP amount of the electrode plate is larger than 100 ppm, the flexibility of the electrode plate can be ensured, but since the NMP amount is large, NMP dissolves in the non-aqueous electrolyte and reacts with the positive electrode active material to produce non-aqueous solution. The electrolyte changes in quality and adversely affects cycle characteristics and the like.
In another embodiment of the present invention, the positive electrode plate and / or the negative electrode plate contains 10 ppm or more and 100 ppm or less of N-methylpyrrolidone in at least the inner part of the winding having a radius of curvature of 2 mm or less.
This is because, in the case of a cylindrical non-aqueous electrolyte secondary battery among the wound non-aqueous electrolyte secondary batteries, cracks occur in the portion of the electrode plate where the radius of curvature of the inner periphery of the electrode plate group is the smallest. Or the mixture and the current collector are easily peeled off. By including the amount of NMP in the part of the electrode plate so that the amount of NMP is 10 ppm or more and 100 ppm or less, the flexibility of the electrode plate is improved, and cracks and peeling can be prevented. In the case of a rectangular nonaqueous electrolyte secondary battery, the cylindrical nonaqueous electrolyte secondary battery is also applied to the electrode plate portion having the smallest radius of curvature even when the electrode plate group is wound flat. In the same manner as in the above, by including NMP so that the amount of NMP is 10 ppm or more and 100 ppm or less, the flexibility of the electrode plate is improved, and cracks and peeling can be prevented.
以下、本発明の一実施の形態について、図面を参照して説明する。 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
図１に、本発明の一実施例である円筒型リチウム二次電池の縦断面概略図を示す。 FIG. 1 is a schematic longitudinal sectional view of a cylindrical lithium secondary battery which is an embodiment of the present invention.
図１において、正極板５と、負極板６と、および両極の間にセパレータ７を介在させ、それらを渦巻き状に捲回し、極板群４を構成している。極板群４は、直径１３．８ｍｍ、高さ５０ｍｍのステンレス鋼板からなる電池ケース１に挿入した。正極板５からは正極リード５ａが引き出され、封口板２に溶接により接続されている。負極板６からは負極リード６ａが引き出され、電池ケース１の底部に溶接により接続されている。封口板２は、絶縁パッキング３を介して電池ケース１でかしめによる封口されている。また、絶縁リング８は、極板群４の上下にそれぞれ設けられている。 In FIG. 1, a separator 7 is interposed between a positive electrode plate 5, a negative electrode plate 6, and both electrodes, and these are wound in a spiral shape to constitute an electrode plate group 4. The electrode plate group 4 was inserted into a battery case 1 made of a stainless steel plate having a diameter of 13.8 mm and a height of 50 mm. A positive electrode lead 5 a is drawn out from the positive electrode plate 5 and connected to the sealing plate 2 by welding. A negative electrode lead 6 a is drawn out from the negative electrode plate 6 and connected to the bottom of the battery case 1 by welding. The sealing plate 2 is sealed by caulking with the battery case 1 through the insulating packing 3. The insulating rings 8 are provided above and below the electrode plate group 4, respectively.
以下、正極板５、負極板６、非水電解液について説明する。 Hereinafter, the positive electrode plate 5, the negative electrode plate 6, and the non-aqueous electrolyte will be described.
正極板５は、正極活物質であるＬｉＣｏＯ2の粉末１００重量部と、導電材としてアセチレンブラックを５重量部と、および結着剤としてＰＶＤＦを５重量部を、適量のＮＭＰの有機溶剤に添加して、ペースト状の正極合剤を調整した。この正極合剤を厚さ０．０１０ｍｍのアルミニウム箔（図示せず）表面に塗着し、乾燥した。乾燥後、ロールプレス機によって厚さ０．１７ｍｍに圧延し、幅３５ｍｍ、長さ２５０ｍｍの大きさに切り出し正極板５とした。 The positive electrode plate 5 is prepared by adding 100 parts by weight of LiCoO 2 powder as a positive electrode active material, 5 parts by weight of acetylene black as a conductive material, and 5 parts by weight of PVDF as a binder to an appropriate amount of an organic solvent of NMP. Thus, a paste-like positive electrode mixture was prepared. This positive electrode mixture was applied to the surface of an aluminum foil (not shown) having a thickness of 0.010 mm and dried. After drying, it was rolled to a thickness of 0.17 mm by a roll press machine, cut into a size of 35 mm in width and 250 mm in length to obtain a positive electrode plate 5.
負極板６は、負極活物質であるコークスを加熱処理して得た炭素粉末１００重量部に、結着剤としてスチレン系結着剤を１０重量部混合し、これをカルボキシメチルセルロースの水溶液に懸濁させてペースト状の負極合剤を調整した。この負極合剤を厚さ０．０１５ｍｍの銅箔の表面に塗着し、乾燥した。乾燥後、ロールプレス機によって厚さ０．２ｍｍに圧延し、幅３７ｍｍ、長さ２８０ｍｍの大きさに切り出し、負極板とした。 The negative electrode plate 6 is obtained by mixing 10 parts by weight of a styrene-based binder as a binder with 100 parts by weight of carbon powder obtained by heat-treating coke, which is a negative electrode active material, and suspending this in an aqueous solution of carboxymethyl cellulose. Thus, a paste-like negative electrode mixture was prepared. This negative electrode mixture was applied to the surface of a copper foil having a thickness of 0.015 mm and dried. After drying, it was rolled to a thickness of 0.2 mm by a roll press and cut into a size of 37 mm width and 280 mm length to obtain a negative electrode plate.
非水電解液は、炭酸エチレンと炭酸ジエチルの等容積混合溶媒に、六フッ化燐酸リチウム１．０ｍｏｌ／Ｌで溶解した。所定量の非水電解液を極板群４に注入した。 The nonaqueous electrolytic solution was dissolved in 1.0 mol / L of lithium hexafluorophosphate in an equal volume mixed solvent of ethylene carbonate and diethyl carbonate. A predetermined amount of non-aqueous electrolyte was injected into the electrode plate group 4.
定格容量が５００ｍＡｈの円筒型リチウム二次電池を作製した。 A cylindrical lithium secondary battery having a rated capacity of 500 mAh was produced.
（実施例１）
極板群４を作製する前に、ＮＭＰ量が１０ｐｐｍになるように、正極板５および負極板６全体にスプレーにより噴霧した。これら極板を用いて円筒型リチウム二次電池を作製した。
Example 1
Before producing the electrode plate group 4, the entire positive electrode plate 5 and negative electrode plate 6 were sprayed so that the amount of NMP was 10 ppm. Cylindrical lithium secondary batteries were produced using these electrode plates.
（実施例２）
ＮＭＰ量が５０ｐｐｍになるようにした以外は、実施例１と同様にした。
(Example 2)
Example 1 was repeated except that the amount of NMP was 50 ppm.
（実施例３）
ＮＭＰ量が１００ｐｐｍになるようにした以外は、実施例１と同様にした。
(Example 3)
The procedure was the same as Example 1 except that the amount of NMP was 100 ppm.
（比較例１）
ＮＭＰ量が５ｐｐｍになるようにした以外は、実施例１と同様にした。
(Comparative Example 1)
Example 1 was repeated except that the amount of NMP was 5 ppm.
（比較例２）
ＮＭＰ量が１５０ｐｐｍになるようにした以外は、実施例１と同様にした。
(Comparative Example 2)
Example 1 was repeated except that the amount of NMP was 150 ppm.
（実施例４）
極板群４を作製する前に、極板群４の最内周部から曲率半径が２ｍｍ以下となる３周目までの正極板５および負極板６の部分に、ＮＭＰ量が１０ｐｐｍになるようにスプレーにより噴霧した。これら極板を用いて円筒型リチウム二次電池を作製した。
Example 4
Before producing the electrode plate group 4, the amount of NMP is 10 ppm in the portions of the positive electrode plate 5 and the negative electrode plate 6 from the innermost peripheral part of the electrode plate group 4 to the third turn where the radius of curvature is 2 mm or less. Sprayed with a spray. Cylindrical lithium secondary batteries were produced using these electrode plates.
（実施例５）
ＮＭＰ量が１００ｐｐｍになるようにした以外は、実施例４と同様とした。
(Example 5)
The procedure was the same as Example 4 except that the amount of NMP was 100 ppm.
（比較例３）
ＮＭＰ量が５ｐｐｍになるようにした以外は、実施例４と同様とした。
(Comparative Example 3)
The procedure was the same as Example 4 except that the amount of NMP was 5 ppm.
（比較例４）
ＮＭＰ量が１５０ｐｐｍになるようにした以外は、実施例４と同様とした。
(Comparative Example 4)
The procedure was the same as Example 4 except that the amount of NMP was 150 ppm.
また、実施例１〜３および比較例１、２の正極板および負極板について、以下のような評価を行った。 Moreover, the following evaluation was performed about the positive electrode plate of Examples 1-3 and Comparative Examples 1 and 2, and the negative electrode plate.
＜極板の折り曲げ試験＞
それぞれの極板を１０ｍｍ×８０ｍｍの短冊状に切断する。極板の長辺の真中部分を谷折りにした。１８０度折り曲げた後、１００Ｎの力でプレスを行った。折り曲げた極板を元の状態に戻した。この作業を１サイクルとし極板が、折り曲げ部で破断するまで繰り返した。破断するまでの回数をカウントした。このような方法で極板の柔軟性を評価した。
<Bending test of electrode plate>
Each electrode plate is cut into a strip of 10 mm × 80 mm. The middle part of the long side of the electrode plate was valley-folded. After bending 180 degrees, pressing was performed with a force of 100 N. The bent electrode plate was returned to its original state. This operation was repeated for one cycle until the electrode plate broke at the bent portion. The number of times until rupture was counted. The flexibility of the electrode plate was evaluated by such a method.
極板の柔軟性の判断基準として、３回以上の場合を柔軟性良好なものとした。 As a criterion for determining the flexibility of the electrode plate, the case of three or more times was considered to have good flexibility.
また、実施例１〜５および比較例１〜４の円筒型リチウム二次電池について、以下のような評価を行った。 Moreover, the following evaluation was performed about the cylindrical lithium secondary battery of Examples 1-5 and Comparative Examples 1-4.
＜リチウム二次電池の充放電サイクル試験＞
環境温度２０℃において、充電条件は、定電流５００ｍＡで電圧４．２Ｖまで充電し、電圧４．２Ｖに到達した後、トータルの充電時間が２時間になるように定電圧４．２Ｖで充電した。放電条件は、定電流１０００ｍＡで、放電終始電圧３．０Ｖまで放電とした。この充電と放電を１サイクルとし、１００サイクル繰り返した。１サイクル目の放電容量と、１００サイクル目の放電容量から、次式により放電容量維持率を計算した。
<Charge / discharge cycle test of lithium secondary battery>
At an environmental temperature of 20 ° C., the charging conditions were a constant current of 500 mA and a voltage of 4.2 V. After reaching the voltage of 4.2 V, the battery was charged at a constant voltage of 4.2 V so that the total charging time was 2 hours. . The discharge conditions were a constant current of 1000 mA and discharge to a discharge starting voltage of 3.0V. This charge and discharge was taken as one cycle and repeated 100 cycles. From the discharge capacity at the first cycle and the discharge capacity at the 100th cycle, the discharge capacity retention ratio was calculated by the following formula.
放電容量維持率（％）＝１００サイクル目の容量（ｍＡｈ）／１サイクル目の容量（ｍＡｈ）×１００
＜リチウム二次電池のインピーダンス測定＞
充放電サイクル前の円筒型リチウム二次電池のインピーダンスを測定し、充放電を１００サイクル繰り返した後のインピーダンスを測定した。
Discharge capacity retention ratio (%) = capacity at the 100th cycle (mAh) / capacity at the first cycle (mAh) × 100
<Impedance measurement of lithium secondary battery>
The impedance of the cylindrical lithium secondary battery before the charge / discharge cycle was measured, and the impedance after 100 cycles of charge / discharge were measured.
なおＮＭＰ量の測定は極板を小片（約２５ｍｍ2）採取し、液クロマトグラフ法によって定量を行った。 これらの評価結果を表１に示す。 The amount of NMP was measured by taking a small piece (about 25 mm 2 ) of the electrode plate and quantifying it by liquid chromatography. These evaluation results are shown in Table 1.
ＮＭＰ量を１５０ｐｐｍとした比較例２は、実施例１〜３に比べ、極板の折り曲げに対
する破断回数がほぼ同程度だったため、極板の柔軟性もほぼ同程度と言える。しかし、充放電サイクル試験の容量維持率が８２．３％と著しく低下した。また、充放電サイクル後の電池のインピーダンスも６８ｍΩと増加していた。充放電サイクル後、比較例２の電池を分解し、非水電解液を採取して成分分析を行った。その結果、ＮＭＰが正極活物質と化学反応していることが判明した。このことから、充放電サイクル試験によって電池のインピーダンスが上昇したのは、極板中のＮＭＰが非水電解液に溶け出し、更には正極活物質と反応して非水電解液が変質したためであると推察できる。
In Comparative Example 2 in which the amount of NMP was 150 ppm, the number of breaks with respect to the bending of the electrode plate was approximately the same as in Examples 1 to 3, and therefore the flexibility of the electrode plate was approximately the same. However, the capacity maintenance rate of the charge / discharge cycle test was remarkably lowered to 82.3%. In addition, the impedance of the battery after the charge / discharge cycle was increased to 68 mΩ. After the charge / discharge cycle, the battery of Comparative Example 2 was disassembled, and a non-aqueous electrolyte was collected for component analysis. As a result, it was found that NMP chemically reacted with the positive electrode active material. From this, the impedance of the battery was increased by the charge / discharge cycle test because NMP in the electrode plate was dissolved in the non-aqueous electrolyte and further reacted with the positive electrode active material to change the non-aqueous electrolyte. Can be guessed.
実施例４、５は、比較例３に比べ、極板の折り曲げに対する破断回数が向上していることから、極板の柔軟性が向上したと言える。比較例４に比べ、充放電サイクル試験の容量維持率と充放電サイクル後の電池のインピーダンスは良好な結果となった。 In Examples 4 and 5, since the number of breaks for the bending of the electrode plate is improved as compared with Comparative Example 3, it can be said that the flexibility of the electrode plate is improved. Compared with Comparative Example 4, the capacity retention rate of the charge / discharge cycle test and the impedance of the battery after the charge / discharge cycle were favorable.
以上の結果から、極板のＮＭＰ量を１０ｐｐｍ以上１００ｐｐｍ以下にすると、極板の柔軟性が向上すると共に、充放電サイクル特性が良好な円筒型リチウム二次電池を得ることができる。また、極板群の最内周部から曲率半径が２ｍｍ以下の部分の極板に、ＮＭＰ量を１０ｐｐｍ以上１００ｐｐｍ以下含ませても良好な結果が得ることができる。 From the above results, when the amount of NMP of the electrode plate is 10 ppm or more and 100 ppm or less, the flexibility of the electrode plate is improved, and a cylindrical lithium secondary battery with good charge / discharge cycle characteristics can be obtained. Also, good results can be obtained even if the NMP content is included in the electrode plate having a radius of curvature of 2 mm or less from the innermost peripheral part of the electrode plate group in an amount of 10 ppm to 100 ppm.
なお、本実施例において、円筒型リチウム二次電池を用いて評価を行った結果について説明したが、角型など電池形状が異なっても同様の効果が得られる。 In addition, in the present Example, although the result evaluated using the cylindrical lithium secondary battery was demonstrated, the same effect is acquired even if battery shapes, such as a square type, differ.
実施例において、正極活物質としてＬｉＣｏＯ2について説明したが、この正極活物質に限定されるものではない。例えば、リチウム（以下、Ｌｉと略す）と、コバルト（以下、Ｃｏと略す）、ニッケル（以下、Ｎｉと略す）、マンガン（以下、Ｍｎと略す）、アルミニウム（以下、Ａｌと略す）、およびマグネシウム（以下、Ｍｇと略す）からなる群から選ばれた少なくとも１種との複合酸化物であっても実施例と同様の効果が得られる。特に、ＬｉとＮｉ、Ｍｎ、およびＣｏからなる複合酸化物と、ＬｉとＮｉ、Ｃｏ、およびＡｌからなる複合酸化物においては良好な結果が得られる。その理由は以下の通りである。リチウム二次電池の容量は電池の単位体積当りの正極活物質重量によって決まる。それら複合酸化物は真密度がＬｉＣｏＯ2に比べて低いため、電池容量を上げるためには、正極板におけるそれら複合酸化物の単位体積当りの重量を上げる必要がある。その方法として、正極板をロールプレス機等で圧延することにより、正極板におけるそれら複合酸化物の充填密度を上げる方法が一般的である。このように正極板の充填密度を上げたことにより、正極板の柔軟性が失われ硬くなる。このような場合において、ＮＭＰを含ませることにより正極板の柔軟性が向上させることができる。 In the examples, LiCoO 2 has been described as the positive electrode active material, but is not limited to this positive electrode active material. For example, lithium (hereinafter abbreviated as Li), cobalt (hereinafter abbreviated as Co), nickel (hereinafter abbreviated as Ni), manganese (hereinafter abbreviated as Mn), aluminum (hereinafter abbreviated as Al), and magnesium Even if it is a complex oxide with at least one selected from the group consisting of (hereinafter abbreviated as Mg), the same effects as in the examples can be obtained. In particular, good results are obtained with a composite oxide composed of Li and Ni, Mn, and Co and a composite oxide composed of Li, Ni, Co, and Al. The reason is as follows. The capacity of the lithium secondary battery is determined by the weight of the positive electrode active material per unit volume of the battery. Since these composite oxides have a lower true density than LiCoO 2 , it is necessary to increase the weight per unit volume of these composite oxides in the positive electrode plate in order to increase the battery capacity. As the method, a method of increasing the packing density of the composite oxide in the positive electrode plate by rolling the positive electrode plate with a roll press machine or the like is common. By increasing the packing density of the positive electrode plate in this way, the flexibility of the positive electrode plate is lost and hardened. In such a case, the flexibility of the positive electrode plate can be improved by including NMP.
実施例において、ＮＭＰを極板に含ませる方法として、スプレーによる噴霧の方法について説明したが、そのほかの方法として、刷毛等によって塗布しても同様の効果が得られる。 In the examples, the spraying method by spraying has been described as a method of including NMP in the electrode plate. However, as another method, the same effect can be obtained by applying with a brush or the like.
実施例において、極板の柔軟性を向上させる溶剤としてＮＭＰについて説明したが、非水電解液の非水溶媒として用いる炭酸エチレン、炭酸ジエチル、プロピレンカーボネートなどの環状エステル、テトラヒドロフランなどの環状エーテル、ジメトキシエタンなどの鎖状エーテル、プロピオン酸メチルなどの鎖状エステルなどの非水溶媒を用いても同様の効果が得られる。 In the examples, NMP was described as a solvent for improving the flexibility of the electrode plate. However, cyclic esters such as ethylene carbonate, diethyl carbonate, and propylene carbonate, cyclic ethers such as tetrahydrofuran, dimethoxy, and the like used as nonaqueous solvents for nonaqueous electrolytes. The same effect can be obtained by using a non-aqueous solvent such as a chain ether such as ethane or a chain ester such as methyl propionate.
また、非水電解液二次電池として、リチウム二次電池について説明したが、リチウム二次電池以外のマグネシウム二次電池などの非水電解液二次電池においても、同様の効果が得られる。 Moreover, although the lithium secondary battery was demonstrated as a nonaqueous electrolyte secondary battery, the same effect is acquired also in nonaqueous electrolyte secondary batteries, such as magnesium secondary batteries other than a lithium secondary battery.
本発明による捲回型非水電解液二次電池は、充放電サイクル特性に優れた寿命の長いポータブル電気機器用電源等として有用である。 The wound non-aqueous electrolyte secondary battery according to the present invention is useful as a power source for portable electric equipment having excellent charge / discharge cycle characteristics and a long life.
１ 電池ケース
２ 封口板
３ 絶縁パッキング
４ 極板群
５ 正極板
５ａ 正極リード
６ 負極板
６ａ 負極リード
７ セパレータ
８ 絶縁リング
DESCRIPTION OF SYMBOLS 1 Battery case 2 Sealing plate 3 Insulation packing 4 Electrode plate group 5 Positive electrode plate 5a Positive electrode lead 6 Negative electrode plate 6a Negative electrode lead 7 Separator 8 Insulation ring
Claims (2)
2. The wound nonaqueous electrolyte secondary battery according to claim 1, wherein the positive electrode plate and / or the negative electrode plate contains 10 ppm or more and 100 ppm or less of N-methylpyrrolidone in at least a portion inside the winding having a radius of curvature of 2 mm or less. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2005087851A JP2006269321A (en) | 2005-03-25 | 2005-03-25 | Winding type non-aqueous electrolyte secondary battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2005087851A JP2006269321A (en) | 2005-03-25 | 2005-03-25 | Winding type non-aqueous electrolyte secondary battery |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2006269321A true JP2006269321A (en) | 2006-10-05 |
Family
ID=37205047
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2005087851A Pending JP2006269321A (en) | 2005-03-25 | 2005-03-25 | Winding type non-aqueous electrolyte secondary battery |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2006269321A (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011100591A (en) * | 2009-11-05 | 2011-05-19 | Hitachi Vehicle Energy Ltd | Square shape lithium secondary battery |
| CN102237549A (en) * | 2010-04-26 | 2011-11-09 | 深圳市比克电池有限公司 | Lithium ion battery, electrolyte thereof and preparation method thereof |
| JP2013065409A (en) * | 2011-09-15 | 2013-04-11 | Toyota Motor Corp | Lithium secondary battery |
| WO2015011965A1 (en) * | 2013-07-24 | 2015-01-29 | 株式会社豊田自動織機 | Lithium-ion secondary battery |
| JP2016038962A (en) * | 2014-08-06 | 2016-03-22 | 株式会社豊田自動織機 | Positive electrode for lithium ion secondary battery and method for manufacturing the same, and lithium ion secondary battery and method for manufacturing the same |
| WO2016067084A1 (en) * | 2014-10-29 | 2016-05-06 | Toyota Jidosha Kabushiki Kaisha | Non-aqueous electrolyte secondary battery, electrode body used therefor, and method of manufacturing the electrode body |
| WO2016103971A1 (en) * | 2014-12-22 | 2016-06-30 | 株式会社 豊田自動織機 | Power storage device |
| JPWO2021090680A1 (en) * | 2019-11-07 | 2021-05-14 |
-
2005
- 2005-03-25 JP JP2005087851A patent/JP2006269321A/en active Pending
Cited By (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011100591A (en) * | 2009-11-05 | 2011-05-19 | Hitachi Vehicle Energy Ltd | Square shape lithium secondary battery |
| CN102237549A (en) * | 2010-04-26 | 2011-11-09 | 深圳市比克电池有限公司 | Lithium ion battery, electrolyte thereof and preparation method thereof |
| JP2013065409A (en) * | 2011-09-15 | 2013-04-11 | Toyota Motor Corp | Lithium secondary battery |
| WO2015011965A1 (en) * | 2013-07-24 | 2015-01-29 | 株式会社豊田自動織機 | Lithium-ion secondary battery |
| JP2015026452A (en) * | 2013-07-24 | 2015-02-05 | 株式会社豊田自動織機 | Lithium ion secondary battery |
| JP2016038962A (en) * | 2014-08-06 | 2016-03-22 | 株式会社豊田自動織機 | Positive electrode for lithium ion secondary battery and method for manufacturing the same, and lithium ion secondary battery and method for manufacturing the same |
| CN107148688B (en) * | 2014-10-29 | 2019-12-24 | 丰田自动车株式会社 | Nonaqueous electrolyte secondary battery, electrode body for nonaqueous electrolyte secondary battery, and method for manufacturing electrode body |
| JP2016085941A (en) * | 2014-10-29 | 2016-05-19 | トヨタ自動車株式会社 | Nonaqueous electrolyte secondary battery, and electrode body used therefor |
| CN107148688A (en) * | 2014-10-29 | 2017-09-08 | 丰田自动车株式会社 | Rechargeable nonaqueous electrolytic battery, the electrode body for rechargeable nonaqueous electrolytic battery and the method for manufacturing electrode body |
| US10347946B2 (en) | 2014-10-29 | 2019-07-09 | Toyota Jidosha Kabushiki Kaisha | Non-aqueous electrolyte secondary battery, electrode body used therefor, and method of manufacturing the electrode body |
| WO2016067084A1 (en) * | 2014-10-29 | 2016-05-06 | Toyota Jidosha Kabushiki Kaisha | Non-aqueous electrolyte secondary battery, electrode body used therefor, and method of manufacturing the electrode body |
| DE112015004925B4 (en) | 2014-10-29 | 2022-01-13 | Toyota Jidosha Kabushiki Kaisha | Non-aqueous electrolyte secondary battery, electrode body used therefor, and method of manufacturing the electrode body |
| WO2016103971A1 (en) * | 2014-12-22 | 2016-06-30 | 株式会社 豊田自動織機 | Power storage device |
| JPWO2016103971A1 (en) * | 2014-12-22 | 2017-09-28 | 株式会社豊田自動織機 | Power storage device |
| JPWO2021090680A1 (en) * | 2019-11-07 | 2021-05-14 | ||
| WO2021090680A1 (en) * | 2019-11-07 | 2021-05-14 | 株式会社村田製作所 | Positive electrode for secondary battery and secondary battery |
| CN114651343A (en) * | 2019-11-07 | 2022-06-21 | 株式会社村田制作所 | Positive electrode for secondary battery and secondary battery |
| JP7392733B2 (en) | 2019-11-07 | 2023-12-06 | 株式会社村田製作所 | Positive electrode for secondary batteries and secondary batteries |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3978881B2 (en) | Non-aqueous electrolyte and lithium secondary battery using the same | |
| WO2009150773A1 (en) | Charging method and discharging method of lithium ion secondary battery | |
| JP3232910B2 (en) | Non-aqueous electrolyte secondary battery and method of manufacturing the same | |
| JP2010267540A (en) | Nonaqueous electrolyte secondary battery | |
| JP2008243684A (en) | Lithium secondary battery | |
| JP2006269321A (en) | Winding type non-aqueous electrolyte secondary battery | |
| JP2009245808A (en) | Lithium ion secondary battery, and power source for electric vehicle | |
| JP2006222072A (en) | Nonaqueous electrolyte secondary battery | |
| JP2009176448A (en) | Nonaqueous electrolyte secondary battery | |
| KR100313633B1 (en) | Secondary battery | |
| JP2007165224A (en) | Nonaqueous electrolytic secondary battery | |
| KR20110100301A (en) | Non-aqueous electrolyte secondary battery, and method for charging same | |
| JP2008103094A (en) | Non-aqueous secondary battery | |
| JP2001189154A (en) | Lithium secondary battery | |
| JP2007042486A (en) | Manufacturing method of nonaqueous electrolyte secondary battery | |
| JP2015037018A (en) | Sealed type nonaqueous electrolyte secondary battery | |
| JP2001210318A (en) | Manufacturing method of negative electrode for nonaqueous electrolytic solution secondary battery | |
| JP2001297750A (en) | Power-generating element for lithium secondary battery and lithium secondary battery using same | |
| JP4114259B2 (en) | Electrolyte for lithium secondary battery and lithium secondary battery using the same | |
| JP2006172901A (en) | Negative electrode for non-aqueous electrolyte secondary battery, and the non-aqueous electrolyte secondary battery using the same | |
| JP2007220455A (en) | Nonaqueous electrolyte secondary battery | |
| JP4016497B2 (en) | Non-aqueous electrolyte and lithium secondary battery using the same | |
| JP3329161B2 (en) | Non-aqueous electrolyte secondary battery | |
| JP2002110251A (en) | Lithium ion secondary battery | |
| JPH05174872A (en) | Nonaqueous electrolyte secondary battery |