JP2007200827A - Non-aqueous electrolyte secondary battery - Google Patents

Non-aqueous electrolyte secondary battery Download PDF

Info

Publication number
JP2007200827A
JP2007200827A JP2006021145A JP2006021145A JP2007200827A JP 2007200827 A JP2007200827 A JP 2007200827A JP 2006021145 A JP2006021145 A JP 2006021145A JP 2006021145 A JP2006021145 A JP 2006021145A JP 2007200827 A JP2007200827 A JP 2007200827A
Authority
JP
Japan
Prior art keywords
positive electrode
active material
electrode active
battery
electrode plate
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
Application number
JP2006021145A
Other languages
Japanese (ja)
Inventor
Yuichi Ito
裕一 伊藤
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sanyo Electric Co Ltd
Sanyo GS Soft Energy Co Ltd
Original Assignee
Sanyo Electric Co Ltd
Sanyo GS Soft Energy Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Sanyo Electric Co Ltd, Sanyo GS Soft Energy Co Ltd filed Critical Sanyo Electric Co Ltd
Priority to JP2006021145A priority Critical patent/JP2007200827A/en
Publication of JP2007200827A publication Critical patent/JP2007200827A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Landscapes

  • Secondary Cells (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-aqueous electrolyte secondary battery excellent in press working performance of a positive electrode plate, capable of making the positive electrode plate and the battery highly dense, excellent in charge and discharge cycle characteristics of the positive electrode, and excellent in high temperature shell life characteristics. <P>SOLUTION: Li<SB>2</SB>CO<SB>3</SB>and Co<SB>3</SB>O<SB>4</SB>are mixed and calcined and LiCoO<SB>2</SB>with D50% particle size of 7 μm or more is obtained, and Co<SB>3</SB>O<SB>4</SB>is mixed to the LiCoO<SB>2</SB>obtained so that the ratio of Co<SB>3</SB>O<SB>4</SB>to the total mass of the positive electrode active material after mixture may be 0.1 wt.% or more and 5 wt.% or less and the positive electrode active material is obtained. The positive electrode plate 4 is formed using this positive electrode active material, and the non-aqueous electrolyte secondary battery 1 is manufactured using this positive electrode plate 4 formed, a negative electrode plate 3, a separator 5, and a non-aqueous electrolyte. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、ＬｉＣｏＯ2 を含む正極活物質を用いてなる非水電解質二次電池に関する。 The present invention relates to a nonaqueous electrolyte secondary battery using a positive electrode active material containing LiCoO 2 .

近年、携帯電話機、ノート型パーソナルコンピュータ、ビデオカメラ等の携帯可能な電子機器の高性能化、小型軽量化が進んでおり、これら電子機器に使用する高エネルギー密度の電池に対する要求が高まっている。このような要求を満たす二次電池として、リチウムイオン電池が挙げられる。   In recent years, portable electronic devices such as mobile phones, notebook personal computers, and video cameras have been improved in performance and reduced in size and weight, and the demand for high energy density batteries used in these electronic devices is increasing. As a secondary battery that satisfies such requirements, a lithium ion battery can be cited.

特許文献１には、Ｌｉ2 ＣＯ3 とＣｏ3 Ｏ4 との混合物を、焼成雰囲気中の酸素濃度を５容量％以上に制御し、かつ加熱温度５００℃以上の昇温速度を５℃／ｍｉｎ以下に設定した状態で、温度６００〜１０００℃で焼成処理してＬｉＣｏＯ2を得る製造方法の発明が開示されている。この製造方法によれば、Ｃｏ3 Ｏ4 の残存量が少ないＬｉＣｏＯ2が得られ、正極活物質のエネルギー密度が高められる。
特許文献２には、Ｌｉ2 ＣＯ3とＣｏ3 Ｏ4 とを、Ｌｉ／Ｃｏのモル比が１〜１．１０となる範囲で混合し、焼成して得られ、遊離のＣｏ3Ｏ4 が０．５質量％以下であるＬｉＣｏＯ2 を含む正極活物質の発明が開示されている。この発明によれば、Ｃｏ3Ｏ4 の残存量が少ないので、正極活物質のエネルギー密度が高い。 Patent Document 1 discloses that a mixture of Li 2 CO 3 and Co 3 O 4 is controlled so that the oxygen concentration in the firing atmosphere is 5% by volume or more, and the heating rate at a heating temperature of 500 ° C. or higher is 5 ° C./min. An invention of a manufacturing method for obtaining LiCoO 2 by firing at a temperature of 600 to 1000 ° C. in the state set as follows is disclosed. According to this manufacturing method, LiCoO 2 with a small amount of remaining Co 3 O 4 is obtained, and the energy density of the positive electrode active material is increased.
Patent Document 2, Li 2 CO 3 and Co 3 O 4, were mixed to the extent that the molar ratio of Li / Co is from 1 to 1.10, obtained by sintering, the free Co 3 O 4 An invention of a positive electrode active material containing LiCoO 2 at 0.5% by mass or less is disclosed. According to this invention, since the remaining amount of Co 3 O 4 is small, the energy density of the positive electrode active material is high.

特許文献３には、Ｌｉ2 ＣＯ3とＣｏ3 Ｏ4 とを、Ｌｉ／Ｃｏのモル比が０．９３〜０．９９となる範囲で混合し、焼成して得られるＬｉＣｏＯ2系の正極活物質を含み、ＣｕＫα線によるＸ線回析図において、２θが１９度付近に認められるＬｉＣｏＯ2 のピークに対する、３７度付近に認められるＣｏ3Ｏ4 のピークの強度比Ｃｏ3 Ｏ4 ／ＬｉＣｏＯ2 が０．００５〜０．０６である非水電解質二次電池の発明が開示されている。この発明によれば、Ａｌ箔の腐食が抑えられ、電池の高温放置特性の低下が抑制される。
特許文献４には、比表面積が３５〜５０ｍ2 ／ｇであるＣｏ3 Ｏ4 とリチウム塩とを原材料とするＬｉＣｏＯ2 を正極活物質とし、ＬｉＣｏＯ2の合成完成度が９５〜１００質量％である非水電解質二次電池の発明が開示されている。この発明によれば、充放電サイクル特性が良好である。
特許第３２７４０１６号公報 特許第３５９３３２２号公報 特許第３２５２４３３号公報 特許第３３４６１８１号公報 In Patent Document 3, Li 2 CO 3 and Co 3 O 4 are mixed in a range where the molar ratio of Li / Co is 0.93 to 0.99 and fired to obtain a LiCoO 2 positive electrode active material. contain substances in X-ray diffraction pattern by CuKα line, to the peak of LiCoO 2 which 2θ is observed in the vicinity of 19 degrees, Co observed near 37 degrees 3 O peak intensity ratio of 4 Co 3 O 4 / LiCoO 2 Discloses an invention of a non-aqueous electrolyte secondary battery having 0.005 to 0.06. According to this invention, the corrosion of the Al foil is suppressed, and the deterioration of the high temperature storage characteristics of the battery is suppressed.
In Patent Document 4, LiCoO 2 using Co 3 O 4 having a specific surface area of 35 to 50 m 2 / g and a lithium salt as raw materials is used as a positive electrode active material, and the synthesis completeness of LiCoO 2 is 95 to 100% by mass. An invention of a certain nonaqueous electrolyte secondary battery is disclosed. According to this invention, the charge / discharge cycle characteristics are good.
Japanese Patent No. 3274016 Japanese Patent No. 3593322 Japanese Patent No. 3252433 Japanese Patent No. 3346181

しかし、特許文献１の発明においては、Ｌｉ／Ｃｏの仕込比が１より小さい場合には、正極活物質の粒径が小さくなるために、正極板のプレス加工性が低下し、正極板及び電池の高密度化が実現出来ず、また、Ｌｉ／Ｃｏの仕込比が１より大きい場合には、残存するＣｏ3 Ｏ4 が極めて少なくなるために、正極の充放電サイクル特性が低下するという問題がある。
特許文献２の発明においては、Ｃｏ3Ｏ4 の残存量が多い場合には、正極活物質の粒径が小さくなるために、正極板のプレス加工性が低下し、正極板及び電池の高密度化が実現出来ず、また、Ｃｏ3Ｏ4 の残存量が少ない場合には、正極の充放電サイクル特性が低下するという問題がある。 However, in the invention of Patent Document 1, when the charging ratio of Li / Co is smaller than 1, the particle size of the positive electrode active material becomes small, so that the press workability of the positive electrode plate is lowered, and the positive electrode plate and the battery When the Li / Co charge ratio is larger than 1, the remaining Co 3 O 4 becomes extremely small, and the charge / discharge cycle characteristics of the positive electrode deteriorate. is there.
In the invention of Patent Document 2, when the remaining amount of Co 3 O 4 is large, the particle size of the positive electrode active material becomes small, so that the press workability of the positive electrode plate is lowered, and the high density of the positive electrode plate and the battery is high. If the remaining amount of Co 3 O 4 is small, the charge / discharge cycle characteristics of the positive electrode deteriorate.

特許文献３の発明においては、焼成時にＣｏ量を多くしているために、正極活物質の粒成長が抑えられ、正極活物質の粒径が小さくなり、正極板のプレス加工性が低下し、正極板及び電池の高密度化の実現が困難であるという問題がある。
特許文献４の発明においては、Ｃｏ3Ｏ4 の比表面積が３５〜５０ｍ2 ／ｇと極めて大きいことから、正極板のプレス加工性が低く、正極板及び電池の高密度化の実現が困難であるという問題がある。 In the invention of Patent Document 3, since the amount of Co is increased during firing, the grain growth of the positive electrode active material is suppressed, the particle size of the positive electrode active material is reduced, and the press workability of the positive electrode plate is reduced. There is a problem that it is difficult to increase the density of the positive electrode plate and the battery.
In the invention of Patent Document 4, since the specific surface area of Co 3 O 4 is as large as 35 to 50 m 2 / g, the press workability of the positive electrode plate is low, and it is difficult to realize high density of the positive electrode plate and the battery. There is a problem that there is.

本発明は斯かる事情に鑑みてなされたものであり、ＬｉＣｏＯ2 を含み、Ｄ５０％粒径が７μｍ以上である焼成物を得た後に、Ｃｏ3 Ｏ4 を混合して得られる正極活物質を用いることにより、正極板のプレス加工性が良好であり、正極板及び電池を高密度化することが可能であり、しかも正極の充放電サイクル特性が良好である非水電解質二次電池を提供することを目的とする。 The present invention has been made in view of such circumstances. A positive electrode active material obtained by mixing Co 3 O 4 after obtaining a fired product containing LiCoO 2 and having a D50% particle size of 7 μm or more is obtained. By using the positive electrode plate, a non-aqueous electrolyte secondary battery in which the press workability of the positive electrode plate is good, the positive electrode plate and the battery can be densified, and the charge / discharge cycle characteristics of the positive electrode are good is provided. For the purpose.

また、本発明は、Ｃｏ3 Ｏ4を混合した後の正極活物質の総質量に対するＣｏ3 Ｏ4 の比率を０．１質量％以上、５質量％以下にすることにより、正極の充放電サイクル特性が良好であり、しかも高温放置特性が良好である非水電解質二次電池を提供することを目的とする。 Further, the present invention, Co 3 O 4 Co 3 O 4 of the ratio 0.1 mass% or more relative to the total weight of the positive electrode active material were mixed by 5 mass% or less, the charge and discharge cycles of the positive electrode An object of the present invention is to provide a nonaqueous electrolyte secondary battery having good characteristics and good high-temperature storage characteristics.

第１発明に係る非水電解質二次電池は、リチウム化合物とコバルト化合物とを焼成して得られるＬｉＣｏＯ2 を含む正極活物質を用いてなる非水電解質二次電池において、前記正極活物質は、焼成により、ＬｉＣｏＯ2を含み、体積基準によるＤ５０％粒径が７μｍ以上である焼成物を得、得られた焼成物にＣｏ3 Ｏ4 を混合してなることを特徴とする。 The nonaqueous electrolyte secondary battery according to the first invention is a nonaqueous electrolyte secondary battery using a positive electrode active material containing LiCoO 2 obtained by firing a lithium compound and a cobalt compound. By firing, a fired product containing LiCoO 2 and having a D50% particle size of 7 μm or more based on volume is obtained, and the obtained fired product is mixed with Co 3 O 4 .

ここで、Ｄ５０％粒径とは、粒径が小さいものからその体積を積算し、積算した体積が全体の５０％となったときの粒径をいう。
本発明においては、ＬｉＣｏＯ2 を含む焼成物のＤ５０％粒径が７μｍ以上であるので、正極活物質の充填性が良好であり、正極板を所定の厚みにプレスする際に、１回のプレス加工で済み、正極板及び電池の高密度化を実現することが出来る。焼成物のＤ５０％粒径が７μｍ未満である場合は、正極活物質の充填性が不十分であり、正極板のプレス加工性が低い。
本発明において、焼成物を得た後にＣｏ3 Ｏ4 を混合するのは、Ｃｏ3Ｏ4 を過剰にして焼成した場合、焼成時にＬｉ2 ＣＯ3 が不足するので、正極活物質の粒径を大きくするのが困難であるからである。そして、本発明においてはＬｉＣｏＯ2を含む焼成物を得た後にＣｏ3 Ｏ4 を添加して混合し、正極活物質を得るので、正極の充放電サイクル特性が良好である。これは、充電時に、ＬｉＣｏＯ2より反応性が高いＣｏ3 Ｏ4 が分解するので、ＬｉＣｏＯ2 の劣化が抑制されるためと考えられる。 Here, the D50% particle size means the particle size when the volume is integrated from the smallest particle size and the integrated volume is 50% of the total.
In the present invention, since the D50% particle size of the fired product containing LiCoO 2 is 7 μm or more, the filling property of the positive electrode active material is good, and when the positive electrode plate is pressed to a predetermined thickness, one press is performed. Processing is sufficient, and high density of the positive electrode plate and the battery can be realized. When the D50% particle size of the fired product is less than 7 μm, the filling property of the positive electrode active material is insufficient, and the press workability of the positive electrode plate is low.
In the present invention, to mix the Co 3 O 4 after obtaining the fired product, when calcined by an excess of Co 3 O 4, since Li 2 CO 3 is insufficient during firing, the particle diameter of the positive electrode active material This is because it is difficult to enlarge. In the present invention, since a fired product containing LiCoO 2 is obtained and then Co 3 O 4 is added and mixed to obtain a positive electrode active material, the charge / discharge cycle characteristics of the positive electrode are good. This is probably because Co 3 O 4, which has higher reactivity than LiCoO 2 , decomposes at the time of charging, so that deterioration of LiCoO 2 is suppressed.

第２発明に係る非水電解質二次電池は、第１発明において、Ｃｏ3 Ｏ4 を混合した後の正極活物質の総質量に対するＣｏ3Ｏ4 の比率が０．１質量％以上、５質量％以下であることを特徴とする。 The non-aqueous electrolyte secondary battery according to the second invention, in the first invention, Co 3 O 4 Co 3 ratio of O 4 is 0.1 mass% or more relative to the total weight of the positive electrode active material were mixed, 5 mass % Or less.

本発明においては、正極活物質の総質量に対するＣｏ3 Ｏ4 の比率が０．１質量％以上、５質量％以下であるので、正極の充放電サイクル特性が良好であり、かつ電池の高温放置特性も良好である。
正極活物質の総質量に対するＣｏ3 Ｏ4 の比率が０．１質量％未満である場合、充放電サイクル特性の改善が不十分である。また、正極活物質の総質量に対するＣｏ3Ｏ4 の比率が５質量％を超える場合、電池を高温下に放置した際に正極と電解液との反応等によりガスが多量に発生し、電池が膨れるとともに、電池の容量が著しく低下する。 In the present invention, since the ratio of Co 3 O 4 to the total mass of the positive electrode active material is 0.1% by mass or more and 5% by mass or less, the charge / discharge cycle characteristics of the positive electrode are good and the battery is left at high temperature. The characteristics are also good.
When the ratio of Co 3 O 4 to the total mass of the positive electrode active material is less than 0.1% by mass, the charge / discharge cycle characteristics are not sufficiently improved. Further, when the ratio of Co 3 O 4 to the total mass of the positive electrode active material exceeds 5% by mass, a large amount of gas is generated due to the reaction between the positive electrode and the electrolyte when the battery is left at a high temperature, and the battery is As the battery swells, the battery capacity decreases significantly.

第１発明によれば、正極板のプレス加工性が良好であり、正極板及び電池を高密度化することが可能であり、正極の充放電サイクル特性が良好である。   According to the first invention, the press workability of the positive electrode plate is good, the positive electrode plate and the battery can be densified, and the charge / discharge cycle characteristics of the positive electrode are good.

第２発明によれば、正極の充放電サイクル特性が良好であり、しかも電池の高温放置特性が良好である。   According to the second invention, the charge / discharge cycle characteristics of the positive electrode are good, and the high-temperature storage characteristics of the battery are good.

以下、本発明をその実施の形態を示す図面に基づいて具体的に説明する。
本発明の非水電解質二次電池の正極活物質は、リチウム化合物とコバルト化合物とを焼成してＬｉＣｏＯ2 を含み、Ｄ５０％粒径が７μｍ以上である焼成物を得、得られた焼成物にＣｏ3Ｏ4 を混合してなる。
リチウム化合物としては、例えばＬｉ2 ＣＯ3 （炭酸リチウム）、水酸化リチウム、硝酸リチウム等が挙げられる。コバルト化合物としては、例えばＣｏ3Ｏ4 （酸化コバルト）、水酸化コバルト、炭酸コバルト、硝酸コバルト等が挙げられる。リチウム化合物としてはＬｉ2 ＣＯ3、コバルト化合物としては、Ｃｏ3 Ｏ4 が好ましい。
正極活物質は、微量成分として、例えば、Ｍｇ、Ａｌ、Ｃａ、Ｍｎ、Ｆｅ、Ｎｉ、Ｚｎ、Ｚｒ、Ｓｒ、Ｎａ、Ｆ、Ｓ等の元素、並びにこれらの酸化物、水酸化物及び塩等を含んでもよい。正極活物質は、ＬｉＣｏＯ2 と、Ｎｉ、Ｍｎ等の他の遷移金属化合物の単独、又はこれらの複合酸化物との混合物であってもよい。
そして、正極活物質粒子のＢＥＴ比表面積及び粒度分布は、リチウム原料及びコバルト原料の粒子形状等の制御、リチウム原料とコバルト原料との混合比の調整、混合原料の造粒、又はＬｉＣｏＯ2 の焼成条件、他元素の添加等によって制御することが出来る。 Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.
The positive electrode active material of the nonaqueous electrolyte secondary battery of the present invention is obtained by firing a lithium compound and a cobalt compound to obtain a fired product containing LiCoO 2 and having a D50% particle size of 7 μm or more. Co 3 O 4 is mixed.
Examples of the lithium compound include Li 2 CO 3 (lithium carbonate), lithium hydroxide, lithium nitrate and the like. Examples of the cobalt compound include Co 3 O 4 (cobalt oxide), cobalt hydroxide, cobalt carbonate, and cobalt nitrate. Li 2 CO 3 is preferred as the lithium compound, and Co 3 O 4 is preferred as the cobalt compound.
The positive electrode active material includes, for example, elements such as Mg, Al, Ca, Mn, Fe, Ni, Zn, Zr, Sr, Na, F, and S, and oxides, hydroxides, and salts thereof as trace components. May be included. The positive electrode active material may be a mixture of LiCoO 2 and another transition metal compound such as Ni or Mn alone or a composite oxide thereof.
The BET specific surface area and particle size distribution of the positive electrode active material particles are controlled by controlling the particle shape of the lithium raw material and the cobalt raw material, adjusting the mixing ratio of the lithium raw material and the cobalt raw material, granulating the mixed raw material, or firing LiCoO 2 . It can be controlled by the conditions and addition of other elements.

Ｃｏ3 Ｏ4 を混合した後の正極活物質の総質量に対するＣｏ3 Ｏ4 の比率は、０．１質量％以上、５質量％以下であるのが好ましい。
正極板は、正極活物質、導電剤及びバインダからなる正極合剤の層をＡｌ等の金属集電体上に形成することにより作製される。 The ratio of Co 3 O 4 Co 3 O 4 to the total weight of the positive electrode active material was mixed with 0.1 wt% or more, preferably 5 mass% or less.
The positive electrode plate is produced by forming a layer of a positive electrode mixture composed of a positive electrode active material, a conductive agent and a binder on a metal current collector such as Al.

本発明の非水電解質二次電池の負極活物質としては、例えば、Ａｌ、Ｓｉ、Ｐｂ、Ｓｎ、Ｚｎ、Ｃｄ等とＬｉとの合金、ＬｉＦｅ2 Ｏ3 、ＷＯ2 、ＭｏＯ2等の遷移金属酸化物、グラファイト、カーボン等の炭素材料、Ｌｉ3 （Ｌｉ3 Ｎ）等の窒化リチウム、若しくは金属リチウム箔、又は、これらの混合物が用いられ得る。粒状の炭素材料を用いる場合には、例えば、負極活物質及びバインダからなる負極合剤の層を銅等の金属集電体上に形成することで、負極板が作製される。前記炭素材料としては、天然黒鉛、人造黒鉛（ＭＣＭＢ又はＭＣＦ等のメソフェーズ系黒鉛）を用いることが好ましく、メソフェーズ系黒鉛（ＭＣＭＢ又はＭＣＦ）を用いることがさらに好ましい。また、天然黒鉛の表面の一部又は全部を、天然黒鉛よりも結晶性が低い低結晶性炭素で被覆したものを用いてもよい。 Examples of the negative electrode active material of the nonaqueous electrolyte secondary battery of the present invention include alloys of Li, Al, Si, Pb, Sn, Zn, Cd, and the like, and transition metals such as LiFe 2 O 3 , WO 2 , and MoO 2. A carbon material such as oxide, graphite, or carbon, lithium nitride such as Li 3 (Li 3 N), metal lithium foil, or a mixture thereof can be used. In the case of using a granular carbon material, for example, a negative electrode plate is produced by forming a layer of a negative electrode mixture composed of a negative electrode active material and a binder on a metal current collector such as copper. As the carbon material, natural graphite or artificial graphite (mesophase graphite such as MCMB or MCF) is preferably used, and mesophase graphite (MCMB or MCF) is more preferably used. Moreover, you may use what coat | covered the part or all of the surface of natural graphite with the low crystalline carbon whose crystallinity is lower than natural graphite.

非水電解質の溶媒としては、例えばエチレンカーボネート、ビニレンカーボネート、プロピレンカーボネート、ブチレンカーボネート、トリフルオロプロピレンカーボネート、γ−ブチロラクトン、スルホラン、１，２−ジメトキシエタン、１，２−ジエトキシエタン、テトラヒドロフラン、２−メチルテトラヒドロフラン、３−メチル−１，３−ジオキソラン、酢酸メチル、酢酸エチル、プロピオン酸メチル、プロピオン酸エチル、ジメチルカーボネート、ジエチルカーボネート、エチルメチルカーボネート、ジプロピルカーボネート、メチルプロピルカーボネート等の非水溶媒が挙げられ、これらを単独、又は混合して使用することが出来る。また、適宜、ビフェニル、シクロヘキシルベンゼン等の重合剤等の添加剤を、適量含有したものでもよい。   Examples of the nonaqueous electrolyte solvent include ethylene carbonate, vinylene carbonate, propylene carbonate, butylene carbonate, trifluoropropylene carbonate, γ-butyrolactone, sulfolane, 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 2 Non-aqueous solvents such as methyltetrahydrofuran, 3-methyl-1,3-dioxolane, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, dipropyl carbonate, methyl propyl carbonate These can be used alone or in combination. In addition, it may appropriately contain an appropriate amount of an additive such as a polymerization agent such as biphenyl or cyclohexylbenzene.

非水電解質は、これらの非水溶媒に支持塩を溶解して使用する。支持塩として、ＬｉＣｌＯ4 、ＬｉＰＦ6 、ＬｉＢＦ4 、ＬｉＡｓＦ6、ＬｉＣＦ3 ＣＯ2 、ＬｉＣＦ3 ＳＯ3 、ＬｉＣＦ3ＣＦ2 ＳＯ3 、ＬｉＣＦ3 ＣＦ2 ＣＦ2 ＳＯ3、ＬｉＮ（ＳＯ2 ＣＦ3 ）2 、ＬｉＮ（ＳＯ2 ＣＦ2ＣＦ3 ）2 、ＬｉＮ（ＣＯＣＦ3 ）2 、ＬｉＮ（ＣＯＣＦ2ＣＦ3 ）2 、ＬｉＰＦ3 （ＣＦ2 ＣＦ3 ）3、ＬｉＦＯＢ（リチウムジフルオロオキサラートボレート）、及びＬｉＢＯＢ（リチウムビスオキサラートボレート）等の塩、若しくはこれらの混合物を使用することが出来る。 The nonaqueous electrolyte is used by dissolving the supporting salt in these nonaqueous solvents. As supporting salts, LiClO 4 , LiPF 6 , LiBF 4 , LiAsF 6 , LiCF 3 CO 2 , LiCF 3 SO 3 , LiCF 3 CF 2 SO 3 , LiCF 3 CF 2 CF 2 SO 3 , LiN (SO 2 CF 3 ) 2 , LiN (SO 2 CF 2 CF 3 ) 2 , LiN (COCF 3 ) 2 , LiN (COCF 2 CF 3 ) 2 , LiPF 3 (CF 2 CF 3 ) 3 , LiFOB (lithium difluorooxalate borate), and LiBOB ( A salt such as lithium bisoxalate borate) or a mixture thereof can be used.

本発明の非水電解質二次電池は、通常、その構成として正極、負極及びセパレータと非水電解質との組み合わせからなるが、セパレータとしては、多孔性ポリオレフィン膜や多孔性ポリ塩化ビニル膜等の多孔性ポリマー膜、若しくは、リチウムイオン又はイオン導電性ポリマー電解質膜を、単独、又は組み合わせて使用することが出来る。
また、電池の形状は、特に限定されるものではなく、本発明は、角形、円筒形、長円筒形、コイン形、ボタン形、シート形電池等の様々な形状の非水電解質二次電池に適用可能である。 The non-aqueous electrolyte secondary battery of the present invention is usually composed of a combination of a positive electrode, a negative electrode, and a separator and a non-aqueous electrolyte as its configuration. As the separator, porous separators such as a porous polyolefin film and a porous polyvinyl chloride film are used. The conductive polymer film, or the lithium ion or ion conductive polymer electrolyte film can be used alone or in combination.
In addition, the shape of the battery is not particularly limited, and the present invention is applicable to non-aqueous electrolyte secondary batteries having various shapes such as a square, cylindrical, long cylindrical, coin, button, and sheet batteries. Applicable.

以下に好適な実施例を用いて本発明を説明するが、本実施例に記載した正極、負極、電解液、セパレータ及び電池の作製方法は一例であり、本発明は、本実施例により、何ら限定されるものではなく、その主旨を変更しない範囲において、適宜変更して実施することが出来る。
（実施例１）
図１は、本発明に係る角型の非水電解質二次電池の概略断面図であり、図中、１が非水電解質二次電池である。非水電解質二次電池１は、銅集電体に負極合剤を塗布してなる負極板３、及びＡｌ集電体に正極合剤を塗布してなる正極板４がセパレータ５を介して巻回された扁平巻状電極群（電極エレメント）２と、非水電解液とを電池ケース６に収納してなる、幅３０ｍｍ、高さ４８ｍｍ、厚さ４．２ｍｍのものである。電池ケース６には、安全弁８及び負極端子９を備えた電池蓋７がレーザー溶接によって取り付けられている。また、負極端子９は負極リード１０を介して負極板３と接続され、正極板４は電池ケース６の側壁内面と接触して電気的に接続されている。 Hereinafter, the present invention will be described with reference to preferred examples. However, the positive electrode, the negative electrode, the electrolytic solution, the separator, and the battery manufacturing method described in this example are examples, and the present invention is not limited to this example. The present invention is not limited, and can be implemented with appropriate modifications within a range not changing the gist thereof.
Example 1
FIG. 1 is a schematic cross-sectional view of a rectangular nonaqueous electrolyte secondary battery according to the present invention, in which 1 is a nonaqueous electrolyte secondary battery. The non-aqueous electrolyte secondary battery 1 includes a negative electrode plate 3 formed by applying a negative electrode mixture to a copper current collector, and a positive electrode plate 4 formed by applying a positive electrode mixture to an Al current collector through a separator 5. It is a 30 mm width, 48 mm height, and 4.2 mm thickness formed by storing the rotated flat wound electrode group (electrode element) 2 and the non-aqueous electrolyte in the battery case 6. A battery cover 7 having a safety valve 8 and a negative electrode terminal 9 is attached to the battery case 6 by laser welding. The negative electrode terminal 9 is connected to the negative electrode plate 3 through the negative electrode lead 10, and the positive electrode plate 4 is in contact with and electrically connected to the inner surface of the side wall of the battery case 6.

正極活物質は、Ｌｉ2 ＣＯ3 とＣｏ3 Ｏ4 とを、ＬｉとＣｏとのモル比が１．０３：１．００（Ｌｉ／Ｃｏ仕込比＝１．０３）となるように混合したのちに、９００℃で１０時間焼成してＬｉＣｏＯ2を得、これに正極活物質の総質量に対するＣｏ3 Ｏ4 の比率が０．０８質量％となるようにＣｏ3Ｏ4 を混合して得た。 The positive electrode active material was prepared by mixing Li 2 CO 3 and Co 3 O 4 so that the molar ratio of Li to Co was 1.03: 1.00 (Li / Co feed ratio = 1.03). Then, LiCoO 2 was obtained by firing at 900 ° C. for 10 hours, and this was obtained by mixing Co 3 O 4 so that the ratio of Co 3 O 4 to the total mass of the positive electrode active material was 0.08% by mass. .

得られた正極活物質、導電剤となるアセチレンブラック（ＡＢ）、及びバインダとなるポリフッ化ビニリデン（ＰＶＤＦ）とを、質量比で９６：２：２となるように混合して正極合剤を得、これに溶媒であるＮ−メチル−２−ピロリドン（ＮＭＰ）を適量加えて攪拌することで、正極ペーストを得た。
正極板４は、前記正極ペーストを、ＮＭＰを除いた正極合剤の質量が片面につき０．０２５ｇ／ｃｍ2 となるように、ドクターブレードを用いて、厚み１５μｍのＡｌ箔集電体の両面に塗布し、乾燥させ、続いて、全体の厚みが１７５μｍとなるように、室温下でプレスを行い、作製した。このプレスに要した回数を下記の表１に示す。 The obtained positive electrode active material, acetylene black (AB) serving as a conductive agent, and polyvinylidene fluoride (PVDF) serving as a binder are mixed in a mass ratio of 96: 2: 2 to obtain a positive electrode mixture. A proper amount of N-methyl-2-pyrrolidone (NMP) as a solvent was added thereto and stirred to obtain a positive electrode paste.
The positive electrode plate 4 is formed on both surfaces of an Al foil current collector having a thickness of 15 μm using a doctor blade such that the mass of the positive electrode mixture excluding NMP is 0.025 g / cm 2 per side. It was applied and dried, followed by pressing at room temperature so that the total thickness was 175 μm. The number of times required for this press is shown in Table 1 below.

Figure 2007200827
Figure 2007200827

負極活物質としてのグラファイト（黒鉛）と、バインダとなるＰＶＤＦとを質量比で９０：１０となるように混合して負極合剤を得、これにＮＭＰを適量加えて攪拌することで、負極ペーストを得た。
負極板３は、前記負極ペーストを、ＮＭＰを除いた負極合剤の質量が片面につき０．０１２ｇ／ｃｍ2 となるように、ドクターブレードを用いて、厚み１０μｍの銅箔集電体の両面に塗布し、乾燥させ、続いて、全体の厚みが１７５μｍとなるように、室温下でプレスを行い、作製した。 Graphite (graphite) as a negative electrode active material and PVDF as a binder are mixed so as to have a mass ratio of 90:10 to obtain a negative electrode mixture. Got.
The negative electrode plate 3 was formed on both surfaces of a 10 μm-thick copper foil current collector using a doctor blade so that the negative electrode paste, excluding NMP, had a negative electrode mixture mass of 0.012 g / cm 2 per side. It was applied and dried, followed by pressing at room temperature so that the total thickness was 175 μm.

セパレータ５としては、ポリエチレン製の微多孔膜を用いた。電解液としては、エチレンカーボネート（ＥＣ）とジエチルカーボネート（ＤＥＣ）とを体積比３：７で混合した溶媒に、ＬｉＰＦ6 を１ｍｏｌ／Ｌ溶解させたものを用いた。 As the separator 5, a microporous film made of polyethylene was used. As the electrolytic solution, a solution obtained by dissolving 1 mol / L of LiPF 6 in a solvent in which ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed at a volume ratio of 3: 7 was used.

前記正極板４、負極板３、セパレータ５及び電解液を用いて、非水電解質二次電池１を作製した。
また、前記正極板４を、長辺が２５ｍｍ、短辺が２０ｍｍとなる四角形状に切り出し、この四角形の長辺の端部から５ｍｍまでの部分の正極合剤を剥離してＡｌ箔を露出させ、この部分にＳＵＳ製のリードを取り付け、後述する正極の充放電試験用のビーカーセルの正極板を作製した。
そして、金属Ｌｉ箔を１辺が３０ｍｍとなる正方形状に切り出し、これにＳＵＳ製のリードを取り付け、前記試験用のビーカーセルの負極板を作製した。
Ａｒ雰囲気中にて、前記電解液を入れたビーカーの中に、前記正極板を入れ、この正極板の両面に対向する位置に、前記負極板を入れ、ビーカーセルを作製した。 A nonaqueous electrolyte secondary battery 1 was produced using the positive electrode plate 4, the negative electrode plate 3, the separator 5, and the electrolytic solution.
Further, the positive electrode plate 4 is cut into a quadrangular shape having a long side of 25 mm and a short side of 20 mm, and the positive electrode mixture is peeled off from the end of the long side of the quadrangle to 5 mm to expose the Al foil. A SUS lead was attached to this portion, and a positive electrode plate of a beaker cell for a charge / discharge test of a positive electrode described later was produced.
Then, a metal Li foil was cut into a square shape with one side of 30 mm, and a SUS lead was attached to the metal Li foil to prepare a negative electrode plate for the test beaker cell.
In an Ar atmosphere, the positive electrode plate was placed in a beaker containing the electrolytic solution, and the negative electrode plate was placed at a position facing both surfaces of the positive electrode plate to prepare a beaker cell.

（実施例２〜１２）
焼成後にＣｏ3 Ｏ4 を混合して得られる正極活物質の総質量に対するＣｏ3 Ｏ4 の質量％を表１に示す値となるように変更したこと以外は、実施例１と同様にして電池及びビーカーセルを作製した。 (Examples 2 to 12)
The battery was obtained in the same manner as in Example 1 except that the mass% of Co 3 O 4 relative to the total mass of the positive electrode active material obtained by mixing Co 3 O 4 after firing was changed to the value shown in Table 1. And a beaker cell was prepared.

（実施例１３〜１５）
ＬｉＣｏＯ2 の焼成時のＬｉ／Ｃｏ仕込比を表１に示す値となるように変更したこと以外は、実施例３と同様にして電池及びビーカーセルを作製した。 (Examples 13 to 15)
A battery and a beaker cell were produced in the same manner as in Example 3 except that the Li / Co charge ratio during firing of LiCoO 2 was changed to the value shown in Table 1.

（比較例１〜８）
ＬｉＣｏＯ2 の焼成時のＬｉ／Ｃｏ仕込比を表２に示す値となるように変更し、焼成後にＣｏ3 Ｏ4 を混合しなかったこと以外は、実施例１と同様にして電池及びビーカーセルを作製した。 (Comparative Examples 1-8)
The battery and beaker cell were the same as in Example 1 except that the Li / Co charge ratio during firing of LiCoO 2 was changed to the value shown in Table 2, and that Co 3 O 4 was not mixed after firing. Was made.

Figure 2007200827
Figure 2007200827

（比較例９）
焼成後にＣｏ3 Ｏ4 を混合しなかったこと以外は、実施例１と同様にして電池及びビーカーセルを作製した。 (Comparative Example 9)
A battery and a beaker cell were produced in the same manner as in Example 1 except that Co 3 O 4 was not mixed after firing.

（比較例１０）
ＬｉＣｏＯ2 の焼成時のＬｉ／Ｃｏ仕込比を１．０００に変更し、焼成後にＣｏ3 Ｏ4 を混合して得られる正極活物質の総質量に対するＣｏ3Ｏ4 の質量％を０．２５質量％に変更したこと以外は、実施例１と同様にして電池及びビーカーセルを作製した。 (Comparative Example 10)
The Li / Co charge ratio during firing of LiCoO 2 was changed to 1.000, and the mass percentage of Co 3 O 4 with respect to the total mass of the positive electrode active material obtained by mixing Co 3 O 4 after firing was 0.25 mass A battery and a beaker cell were produced in the same manner as in Example 1 except that the percentage was changed to%.

前記実施例及び比較例のビーカーセルについて、以下の正極の初期充放電容量確認試験及び充放電サイクル試験を行い、正極の充放電サイクル特性の評価を行った。
（初期充放電容量確認試験）
初期充放電容量確認試験は、各実施例及び比較例のビーカーセルにつき、電流１０ｍＡ（１ｍＡ／ｃｍ2 ）で、充電として、電圧４．３Ｖまでの定電流充電を行い、放電として、電圧３．０Ｖまでの定電流放電を行い、初期の充放電量を測定するものである。得られた充放電量を正極活物質の質量で除し、正極活物質の質量当たりの初期の充電量及び放電量の値を得た。この試験結果を表１及び２に示す。
（充放電サイクル試験）
充放電サイクル試験は、各実施例及び比較例のビーカーセルにつき、前記初期充放電容量確認試験と同様の条件で５０サイクルの充放電を行い、５０サイクル目の放電容量を５０サイクル後の放電容量として測定するものである。この５０サイクル後の放電容量を初期放電容量で除した値を充放電サイクル試験における容量保持率とした。この試験結果を表１及び２に示す。 About the beaker cell of the said Example and the comparative example, the following initial stage charging / discharging capacity | capacitance confirmation test and charging / discharging cycle test were done, and the charging / discharging cycle characteristic of the positive electrode was evaluated.
(Initial charge / discharge capacity confirmation test)
In the initial charge / discharge capacity confirmation test, the beaker cells of the examples and comparative examples were charged at a current of 10 mA (1 mA / cm 2 ) at a constant current of up to 4.3 V as a charge, and discharged at a voltage of 3. A constant current discharge up to 0V is performed, and the initial charge / discharge amount is measured. The obtained charge / discharge amount was divided by the mass of the positive electrode active material to obtain values of an initial charge amount and a discharge amount per mass of the positive electrode active material. The test results are shown in Tables 1 and 2.
(Charge / discharge cycle test)
In the charge / discharge cycle test, for each beaker cell of each example and comparative example, 50 cycles of charge / discharge were performed under the same conditions as the initial charge / discharge capacity confirmation test, and the discharge capacity at the 50th cycle was the discharge capacity after 50 cycles. Is to be measured. The value obtained by dividing the discharge capacity after 50 cycles by the initial discharge capacity was defined as the capacity retention rate in the charge / discharge cycle test. The test results are shown in Tables 1 and 2.

前記実施例及び比較例の電池について、以下の高温放置特性の評価を行った。
各実施例及び比較例の電池につき、室温２０℃の雰囲気下、充電電流６００ｍＡ、充電電圧４．２０Ｖの定電流・定電圧で２．５時間充電した後、放電電流６００ｍＡ、終止電圧２．７５Ｖの条件で放電を行い、放電容量を測定し、これを初期容量とした。また、放電後の電池の厚みを測定し、これを初期厚みとした。
前記電池を前記と同様の条件にて再度充電した後、１００℃の雰囲気下、１時間放置した。その後、前記電池を室温にて１０時間冷却し、電池の厚みを測定した。この電池の厚みと初期厚みとの差を高温放置後の電池の膨れ量とした。その後、前記電池を前記と同様の条件にて放電し、得られた放電容量を初期容量で除して、高温放置試験における容量保持率とした。この結果を表１及び２に示す。 The batteries of Examples and Comparative Examples were evaluated for the following high temperature storage characteristics.
The batteries of the examples and comparative examples were charged for 2.5 hours at a constant current and a constant voltage of a charging current of 600 mA and a charging voltage of 4.20 V in an atmosphere at a room temperature of 20 ° C., and then a discharging current of 600 mA and a final voltage of 2.75 V. Discharge was performed under the conditions described above, and the discharge capacity was measured. Moreover, the thickness of the battery after discharge was measured, and this was used as the initial thickness.
The battery was charged again under the same conditions as described above, and then allowed to stand for 1 hour in an atmosphere at 100 ° C. Thereafter, the battery was cooled at room temperature for 10 hours, and the thickness of the battery was measured. The difference between the thickness of the battery and the initial thickness was defined as the amount of swelling of the battery after being left at high temperature. Thereafter, the battery was discharged under the same conditions as described above, and the obtained discharge capacity was divided by the initial capacity to obtain a capacity retention rate in a high temperature standing test. The results are shown in Tables 1 and 2.

ＬｉＣｏＯ2 の焼成時のＬｉ／Ｃｏ仕込比が１．００以下である比較例１〜５及び１０の正極活物質は、Ｌｉ／Ｃｏ仕込比がＬｉＣｏＯ2の反応量論比と等しく、又は反応量論比より小さいので、未反応のＣｏ3 Ｏ4 を含む。この比較例１〜５及び１０の正極活物質のＤ５０％粒径は７μｍ未満であり、Ｌｉ／Ｃｏ仕込比を１．００より大きくした比較例６〜９の正極活物質のＤ５０％粒径７．２〜８．６μｍよりも小さい。これは、過剰なＬｉ2ＣＯ3 を含有しないために、焼成時にＬｉ2 ＣＯ3 が溶融することによってＣｏ3Ｏ4 との反応性が高くなる作用や、ＬｉＣｏＯ2 粒子同士の焼結反応が促進されて、ＬｉＣｏＯ2粒子が大きくなる作用が生じにくかったためであると考えられる。
この比較例１〜５及び１０の正極板を所定の厚みにプレスする際、表２に示したように、２回のプレス加工が必要であり、生産性が著しく劣っていた。これは、比較例１〜５及び１０においては、正極活物質の粒径が小さいために、その充填性が低かったためと考えられる。Ｄ５０％粒径が７μｍ以上である実施例１〜１５、及び比較例６〜９の場合、１回のプレス加工で正極板を所定の厚みにすることが出来、生産性が良好であることが分かる。以上より、Ｄ５０％粒径が７μｍ以上であるＬｉＣｏＯ2を得ることで、正極板のプレス加工性が良好になり、正極板及び電池を高密度化することが可能になることが分かる。 In the positive electrode active materials of Comparative Examples 1 to 5 and 10 in which the Li / Co charge ratio during firing of LiCoO 2 is 1.00 or less, the Li / Co charge ratio is equal to the stoichiometric ratio of LiCoO 2 or the reaction amount Since it is smaller than the theoretical ratio, unreacted Co 3 O 4 is included. The positive electrode active materials of Comparative Examples 1 to 5 and 10 have a D50% particle size of less than 7 μm, and the positive electrode active materials of Comparative Examples 6 to 9 having a Li / Co feed ratio greater than 1.00 have a D50% particle size of 7 Smaller than 2 to 8.6 μm. This is because it does not contain excessive Li 2 CO 3 , so that Li 2 CO 3 is melted during firing, thereby increasing the reactivity with Co 3 O 4 and promoting the sintering reaction between LiCoO 2 particles. This is considered to be because the effect of increasing the LiCoO 2 particles was difficult to occur.
When the positive plates of Comparative Examples 1 to 5 and 10 were pressed to a predetermined thickness, as shown in Table 2, two press processes were required, and the productivity was remarkably inferior. This is presumably because, in Comparative Examples 1 to 5 and 10, since the particle size of the positive electrode active material was small, the filling property was low. In the case of Examples 1 to 15 and Comparative Examples 6 to 9 in which the D50% particle size is 7 μm or more, the positive electrode plate can be made to have a predetermined thickness by one press work, and the productivity should be good. I understand. From the above, it can be seen that by obtaining LiCoO 2 having a D50% particle size of 7 μm or more, the press workability of the positive electrode plate is improved, and the positive electrode plate and the battery can be densified.

比較例６、７、８及び９は、上述したように、正極板のプレス加工性は良好であるが、Ｌｉ／Ｃｏ仕込比がそれぞれ同一である実施例１３、１４、１５及び３と比較すると、正極の５０サイクル後の放電容量が、実施例が１２２ｍＡｈ／ｇ前後であるのに対し、４０ｍＡｈ／ｇ前後であり、極めて小さい。従って、正極の５０サイクル後の容量保持率が、実施例が８１％を超えるのに対し、２６〜２７％であり、著しく劣っている。実施例においては、ＬｉＣｏＯ2 の焼成後にＣｏ3 Ｏ4 を混合しているので、電池の充電時に、ＬｉＣｏＯ2より反応性が高いＣｏ3 Ｏ4 が分解するので、ＬｉＣｏＯ2 の劣化が抑制されると考えられる。以上より、Ｄ５０％粒径が７μｍ以上であるＬｉＣｏＯ2を得た後に、Ｃｏ3 Ｏ4 を混合することで、充放電サイクル特性が良好になることが分かる。 As described above, Comparative Examples 6, 7, 8 and 9 have good press workability of the positive electrode plate, but compared with Examples 13, 14, 15 and 3 in which the Li / Co feed ratio is the same. The discharge capacity after 50 cycles of the positive electrode is extremely small, being around 40 mAh / g, compared with around 122 mAh / g in the examples. Accordingly, the capacity retention after 50 cycles of the positive electrode is 26% to 27%, which is significantly inferior to the example exceeding 81%. In the embodiment, since the mixed Co 3 O 4 after firing of LiCoO 2, during charging of the battery, since the Co 3 O 4 is more reactive than LiCoO 2 is decomposed, the deterioration of the LiCoO 2 is suppressed it is conceivable that. From the above, it can be seen that charge / discharge cycle characteristics are improved by mixing Co 3 O 4 after obtaining LiCoO 2 having a D50% particle size of 7 μm or more.

実施例１〜１２は、Ｌｉ／Ｃｏ仕込比を１．０３０と同一にして、焼成後の正極活物質のＣｏ3 Ｏ4 の含有量を変えているが、Ｃｏ3Ｏ4 の含有量が大きくなるのに従い、正極の５０サイクル後の放電容量が大きくなり、容量保持率が大きくなっている。Ｃｏ3Ｏ4 の含有量が０．０８質量％である実施例１の場合、実施例２〜１２の場合の容量保持率が８１％以上であるのに対し、６０％であり、充放電サイクル特性が不十分である。Ｃｏ3Ｏ4 の含有量が大きくなるのに従い、容量保持率は向上するが、高温放置後の電池の膨れ量が大きくなり、高温放置後の容量保持率が低下している。特に実施例１２の容量保持率は１．４％であり、著しく劣っている。電池の膨れ量が大きくなる原因としては、ＬｉＣｏＯ2よりも反応性が高いと考えられるＣｏ3 Ｏ4 の含有量が多くなると、高温環境下において、電解液が分解し、ガスが発生するためと考えられる。そして、容量保持率が著しく低下する原因としては、電池の大きな膨れのために正極板と負極板との間隔が広くなることによる充放電時の抵抗の増加、又はセパレータの劣化、及び電解液量の不足等が生じ、電池として機能し得ない不可逆の劣化が生じたことが考えられる。以上より、充放電サイクル特性及び電池の高温放置特性を良好にするためには、正極活物質中のＣｏ3Ｏ4 の含有量を０．１質量％以上、５質量％以下にするのが好ましいことが分かる。電池の膨れを抑制するためには、Ｃｏ3Ｏ4 の含有量の上限は３．００％以下であるのが、より好ましく、１．００質量％以下であるのが、さらに好ましい。 In Examples 1 to 12, the Li / Co feed ratio was made the same as 1.030, and the content of Co 3 O 4 of the positive electrode active material after firing was changed, but the content of Co 3 O 4 was large. Accordingly, the discharge capacity after 50 cycles of the positive electrode is increased, and the capacity retention rate is increased. In the case of Example 1 in which the content of Co 3 O 4 is 0.08 mass%, the capacity retention in Examples 2 to 12 is 81% or more, whereas it is 60%, and the charge / discharge cycle Insufficient characteristics. As the content of Co 3 O 4 increases, the capacity retention increases, but the amount of swelling of the battery after leaving at high temperature increases, and the capacity retention after leaving at high temperature decreases. In particular, the capacity retention of Example 12 is 1.4%, which is extremely inferior. The reason why the amount of swelling of the battery becomes large is that when the content of Co 3 O 4 which is considered to be higher than LiCoO 2 is increased, the electrolyte is decomposed and gas is generated in a high temperature environment. Conceivable. The reason for the significant decrease in capacity retention is the increase in resistance at the time of charge / discharge due to the wide gap between the positive electrode plate and the negative electrode plate due to the large swelling of the battery, or the deterioration of the separator, and the amount of electrolyte It is conceivable that irreversible deterioration that could not function as a battery occurred. From the above, in order to improve the charge / discharge cycle characteristics and the high-temperature storage characteristics of the battery, the content of Co 3 O 4 in the positive electrode active material is preferably 0.1% by mass or more and 5% by mass or less. I understand that. In order to suppress the swelling of the battery, the upper limit of the content of Co 3 O 4 is more preferably 3.00% or less, and further preferably 1.00% by mass or less.

以上のように、Ｄ５０％粒径が７μｍ以上であるＬｉＣｏＯ2 を焼成した後に、Ｃｏ3 Ｏ4を混合した正極活物質を用いることにより、正極板のプレス加工性が良好であり、容易に正極板の高密度化を実現することが出来、正極の充放電サイクル特性に優れた非水電解質二次電池を得ることが出来る。そして、正極活物質の焼成後に、混合後の正極活物質の総質量に対するＣｏ3Ｏ4 の比率が０．１質量％以上、５質量％以下となるように、Ｃｏ3 Ｏ4 を混合することで、電池の高温放置特性の低下も抑制される。 As described above, after firing LiCoO 2 having a D50% particle size of 7 μm or more, by using a positive electrode active material mixed with Co 3 O 4 , the press workability of the positive electrode plate is good, and the positive electrode is easily High density of the plate can be realized, and a nonaqueous electrolyte secondary battery excellent in charge / discharge cycle characteristics of the positive electrode can be obtained. Then, after firing the positive electrode active material, Co 3 O 4 is mixed so that the ratio of Co 3 O 4 to the total mass of the positive electrode active material after mixing is 0.1 mass% or more and 5 mass% or less. Thus, the deterioration of the high temperature storage characteristics of the battery is also suppressed.

本発明に係る角型の非水電解質二次電池の概略断面図である。1 is a schematic cross-sectional view of a rectangular nonaqueous electrolyte secondary battery according to the present invention.

符号の説明Explanation of symbols

１ 非水電解質二次電池
２ 扁平巻状電極群
３ 負極板
４ 正極板
５ セパレータ
６ 電池ケース
７ 電池蓋
８ 安全弁
９ 負極端子
１０ 負極リード DESCRIPTION OF SYMBOLS 1 Nonaqueous electrolyte secondary battery 2 Flat wound electrode group 3 Negative electrode plate 4 Positive electrode plate 5 Separator 6 Battery case 7 Battery cover 8 Safety valve 9 Negative electrode terminal 10 Negative electrode lead

Claims (2)

リチウム化合物とコバルト化合物とを焼成して得られるＬｉＣｏＯ2 を含む正極活物質を用いてなる非水電解質二次電池において、
前記正極活物質は、焼成により、ＬｉＣｏＯ2 を含み、体積基準によるＤ５０％粒径が７μｍ以上である焼成物を得、得られた焼成物にＣｏ3 Ｏ4 を混合してなることを特徴とする非水電解質二次電池。 In a non-aqueous electrolyte secondary battery using a positive electrode active material containing LiCoO 2 obtained by firing a lithium compound and a cobalt compound,
The positive electrode active material is obtained by firing to obtain a fired product containing LiCoO 2 and having a D50% particle size on a volume basis of 7 μm or more, and mixing the obtained fired product with Co 3 O 4. Non-aqueous electrolyte secondary battery. Ｃｏ3 Ｏ4 を混合した後の正極活物質の総質量に対するＣｏ3 Ｏ4 の比率が０．１質量％以上、５質量％以下である請求項１に記載の非水電解質二次電池。 Co 3 O 4 Co 3 ratio of O 4 is 0.1 mass% or more relative to the total weight of the positive electrode active material were mixed, non-aqueous electrolyte secondary battery according to claim 1 5 mass% or less.
JP2006021145A 2006-01-30 2006-01-30 Non-aqueous electrolyte secondary battery Pending JP2007200827A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2006021145A JP2007200827A (en) 2006-01-30 2006-01-30 Non-aqueous electrolyte secondary battery

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2006021145A JP2007200827A (en) 2006-01-30 2006-01-30 Non-aqueous electrolyte secondary battery

Publications (1)

Publication Number Publication Date
JP2007200827A true JP2007200827A (en) 2007-08-09

Family

ID=38455210

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2006021145A Pending JP2007200827A (en) 2006-01-30 2006-01-30 Non-aqueous electrolyte secondary battery

Country Status (1)

Country Link
JP (1) JP2007200827A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021195906A1 (en) * 2020-03-31 2021-10-07 东莞新能安科技有限公司 Electrochemical apparatus and electronic apparatus using electrochemical apparatus
CN114242935A (en) * 2021-12-16 2022-03-25 珠海冠宇电池股份有限公司 Electrode assembly and application thereof

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001273903A (en) * 2000-03-28 2001-10-05 Matsushita Electric Ind Co Ltd Lithium secondary battery
JP2004196603A (en) * 2002-12-19 2004-07-15 Nippon Chem Ind Co Ltd Lithium cobaltate, its preparation method, and non-aqueous electrolyte secondary battery
JP2005235764A (en) * 2004-02-17 2005-09-02 Samsung Sdi Co Ltd Lithium secondary cell positive electrode activator, and manufacturing method of the same

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001273903A (en) * 2000-03-28 2001-10-05 Matsushita Electric Ind Co Ltd Lithium secondary battery
JP2004196603A (en) * 2002-12-19 2004-07-15 Nippon Chem Ind Co Ltd Lithium cobaltate, its preparation method, and non-aqueous electrolyte secondary battery
JP2005235764A (en) * 2004-02-17 2005-09-02 Samsung Sdi Co Ltd Lithium secondary cell positive electrode activator, and manufacturing method of the same

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021195906A1 (en) * 2020-03-31 2021-10-07 东莞新能安科技有限公司 Electrochemical apparatus and electronic apparatus using electrochemical apparatus
CN114242935A (en) * 2021-12-16 2022-03-25 珠海冠宇电池股份有限公司 Electrode assembly and application thereof

Similar Documents

Publication Publication Date Title
KR102425513B1 (en) Lithium secondary battery
JP7157252B2 (en) Positive electrode additive for lithium secondary battery, manufacturing method thereof, positive electrode for lithium secondary battery containing same, and lithium secondary battery containing same
JP5325888B2 (en) Electrode active material, electrode for non-aqueous secondary battery and non-aqueous secondary battery
JP5341837B2 (en) Positive electrode, non-aqueous electrolyte battery and battery pack
JP5068459B2 (en) Lithium secondary battery
JP5978014B2 (en) Non-aqueous secondary battery
JP2012014851A (en) Electrode for electrochemical element, and nonaqueous secondary battery
JP5224081B2 (en) Nonaqueous electrolyte secondary battery
JP2011023335A (en) Electrode for nonaqueous secondary battery and nonaqueous secondary battery
JP2008198620A (en) Lithium secondary battery
JP2010073686A (en) Electrode for electrochemical element and nonaqueous secondary battery
JP2007287630A (en) Nonaqueous electrolyte secondary battery
JP2013118069A (en) Lithium secondary battery
JP2009212021A (en) Electrode for electrochemical element, nonaqueous secondary battery, and battery system
JP5793411B2 (en) Lithium secondary battery
KR101655241B1 (en) Manufacturing method of lithium manganese complex oxide coated with lithium polysilicate, lithium manganese complex oxide for lithium rechargeable batteries made by the same, and lithium rechargeable batteries comprising the same
JP2009087647A (en) Nonaqueous electrolyte secondary battery
JP5181455B2 (en) Cathode active material for non-aqueous electrolyte secondary battery, method for producing the same, and non-aqueous electrolyte secondary battery using the same
KR102185125B1 (en) Positive active material for rechargeable lithium battery, method of preparing same, and rechargeable lithium battery including same
JP6208584B2 (en) Nonaqueous electrolyte secondary battery
JP2009266433A (en) Positive electrode active substance for non-aqueous electrolyte secondary battery, its manufacturing method, and non-aqueous electrolyte secondary battery using the same
JP2013080726A (en) Positive electrode, nonaqueous electrolyte battery, and battery pack
JP2007200827A (en) Non-aqueous electrolyte secondary battery
JP2014007016A (en) Positive electrode for nonaqueous electrolyte secondary battery, and nonaqueous electrolyte secondary battery
JP7471738B2 (en) Negative electrode active material, negative electrode containing the same, and secondary battery

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20080514

A711 Notification of change in applicant

Free format text: JAPANESE INTERMEDIATE CODE: A711

Effective date: 20110405

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20110520

RD02 Notification of acceptance of power of attorney

Free format text: JAPANESE INTERMEDIATE CODE: A7422

Effective date: 20110720

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20110819

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20110823

A02 Decision of refusal

Free format text: JAPANESE INTERMEDIATE CODE: A02

Effective date: 20120110