JP2004296420A - Organic electrolyte battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electrolyte battery wherein a productivity is improved by shortening the time necessary for an initial charging. <P>SOLUTION: In the organic electrolyte battery including a negative electrode, a positive electrode, and an organic electrolyte liquid, a lithium-containing material with a specific surface area of not less than 1.0 m<SP>2</SP>/g is used as a negative electrode activator, and content ratio of x (mass%) of S in the negative electrode against 100 mass% of the total content of C, O, Na, Mg, Al, Si, S, Ca, Fe, Ni, Cu, and Zr measured by X-ray fluorometric analysis is made not less than two times the content ratio of y (mass%) of S in the positive electrode against 100 mass% of the total content of C, O, Na, Mg, Al, Si, S, Ca, Fe, Ni, Cu, and Zr measured by X-ray fluorometric analysis. It is preferable that the electrolyte liquid contains a certain amount of γ-butyrolactone and/or vinylene carbonate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０１０４】
【表２】

【０１０５】
表１に示す実施例１〜１３の電池の電池特性と、表２に示す比較例１〜５の電池の電池特性の対比から明らかなように、実施例１〜１３の電池は、比較例１〜５の電池に比べて、初回充電電流値を大きくしても反応ムラが生じにくいため電流値を大きくすることができ、その結果、初回充電時間を短くすることができる。また、実施例１〜１３の電池は、負荷特性も優れたものであった。
【０１０６】
実施例１４
負極を以下のとおり作製した。
まず、負極活物質として比表面積３．０ｍ^２ ／ｇの黒鉛を９６質量部用い、Ｓ含有化合物としてベンゼンスルホン酸リチウムを１質量部用い、Ｐ含有化合物としてリン酸リチウムを１質量部用い、バインダーとしてスチレンブタジエンゴム１質量部とカルボキシメチルセルロース１質量部を水に溶解させたものを用い、上記全てを混合して負極塗膜形成用塗料を調製した。
【０１０７】
得られた塗料を厚さ１０μｍの銅箔からなる導電性基体上にアプリケーターを用いて塗布し、１００℃で乾燥して塗膜を形成した。上記銅箔からなる導電性基体の裏面側にも上記塗料を塗布乾燥し電極体を作製した。その後、この電極体を１００℃で１０時間真空乾燥後、ロールプレスして、シート状の負極を得た。この負極の塗膜密度は１．５ｇ／ｃｍ^３ であった。また、上記負極のカールフィッシャー法で測定した水分量は１１８ｐｐｍであった。上記負極中の水分量は負極を２ｃｍ×５ｃｍの試験片に切断し、１７０℃に加熱して出てきた水蒸気をカールフィッシャー装置に導入することにより測定したものである。上記の水分量は、塗膜の質量に対する負極中の水分の質量として表示した。
【０１０８】
正極を以下のとおり作製した。
リチウムコバルト酸化物を９５質量部と、電子伝導助剤としてのカーボンブラックを１質量部と鱗片状黒鉛を１質量部、バインダーとしてのポリビニリデンフルオライドの３質量部をＮ−メチル−２−ピロリドンに溶解させたものを用い、正極塗膜系形成用塗料を調製した。上記塗料の調製は次に示すように行った。まず、Ｎ−メチル−２−ピロリドンにポリビニリデンフルオライドを溶解したバインダー溶液を調製した。つぎに、このバインダー溶液に正極活物質のリチウムコバルト酸化物と電子伝導助剤としてのカーボンブラックと鱗片状黒鉛を加え、混合することによって塗料を調製した。
【０１０９】
そして、得られた塗料を厚さ１５μｍのアルミニウム箔からなる導電性基体上にアプリケーターを用いて塗布し、１００〜１２０℃で乾燥して塗膜を形成した。上記アルミニウム箔の裏面側にも同様に、上記塗料を塗布乾燥し電極体を形成した。この電極体を、１００℃で１０時間真空乾燥後、ロールプレスしてシート状正極を得た。この電極の塗膜密度は３．３０ｇ／ｃｍ^３ であった。
【０１１０】
電解液として、１．２ｍｏｌ／ｌのＬｉＰＦ_６ をエチレンカーボネートとメチルエチルカーボネートとの体積比が１：２の混合溶媒に溶解させたものを用いた。
【０１１１】
筒形有機電解液電池の組み立ては以下のとおり行った。
まず、上記のシート状正極を幅２８ｍｍ×長さ２２０ｍｍの帯状に切断し、シート状負極を幅３０ｍｍ×長さ２６０ｍｍの帯状に切断した。そして、それぞれの電極端部の塗膜の一部を剥がし、金属箔を露出させた部分に、アルミニウム製のリード体を抵抗溶接し、厚み２０μｍで開孔率５０％の微多孔性ポリプロピレンフィルムからなる帯状セパレータを上記シート状正極とシート状負極との間に介在させ、渦巻状に巻回して渦巻状電極体を作製し、その渦巻状電極体を実施例１と同様の電池ケース内に挿入した。そして、負極側のリード体の先端を絶縁体を貫通させて電池ケース内の底部に溶接し、さらに、電池ケースの開口部に絶縁体を挿入し、溝を形成した後、封口板と正極側のリード体を溶接した。そして、このような工程を経て作製された缶体を６０℃で１０時間真空乾燥した後、乾燥雰囲気中で電解液２ｍｌを注入した後、封口して、図１に示す構造で筒形のＲ５型有機電解液電池（外径：１４．９５ｍｍ、高さ：３９．７ｍｍ）を作製した。
【０１１２】
実施例１５
負極活物質として比表面積３．０ｍ^２ ／ｇの黒鉛を９７質量部用い、Ｓ含有化合物としてベンゼンスルホン酸リチウムを０．５質量部用い、Ｐ含有化合物としてリン酸リチウムを０．５質量部用い、バインダーとしてスチレンブタジエンゴム１質量部とカルボキシメチルセルロース１質量部を水に溶解させたものを用い、それ以外は実施例１４と同様に負極を作製した。上記負極の水分量は１２５ｐｐｍであった。また、その負極を用いた以外は、実施例１４と同様に筒形の有機電解液電池を作製した。
【０１１３】
実施例１６
負極活物質として比表面積３．０ｍ^２ ／ｇの黒鉛を９２質量部用い、Ｓ含有化合物としてベンゼンスルホン酸リチウムを３質量部用い、Ｐ含有化合物としてリン酸リチウムを３質量部用い、バインダーとしてスチレンブタジエンゴム１質量部とカルボキシメチルセルロース１質量部を水に溶解させたものを用い、それ以外は実施例１と同様に負極を作製した。上記負極の水分量は１０７ｐｐｍであった。また、その負極を用いた以外は、実施例１４と同様に筒形の有機電解液電池を作製した。
【０１１４】
実施例１７
電解液として、１．２ｍｏｌ／ｌのＬｉＰＦ_６ をエチレンカーボネートとメチルエチルカーボネートとの体積比が１：２の混合溶媒に、γ−ブチロラクトンを体積含有率で３体積％加えて調製したものを用い、それ以外は実施例１４と同様に筒形の有機電解液電池を作製した。
【０１１５】
なお、負極活物質の比表面積は３．０ｍ^２ ／ｇであり、この負極活物質の比表面積１．０ｍ^２ ／ｇあたりのγ−ブチロラクトンの有機電解液中の体積含有率は１．０体積％であった。また、この電池の負極の水分量は１２５ｐｐｍであった。
【０１１６】
実施例１８
電解液として、１．２ｍｏｌ／ｌのＬｉＰＦ_６ をエチレンカーボネートとメチルエチルカーボネートとの体積比が１：２の混合溶媒に、γ−ブチロラクトンを体積含有率で２体積％加えて調製したものを用い、それ以外は実施例１５と同様に筒形の有機電解液電池を作製した。
【０１１７】
なお、負極活物質の比表面積は３．０ｍ^２ ／ｇであり、この負極活物質の比表面積１．０ｍ^２ ／ｇあたりのγ−ブチロラクトンの有機電解液中の体積含有率は０．６７体積％であった。また、この電池の負極の水分量は１２５ｐｐｍであった。
【０１１８】
実施例１９
電解液として、１．２ｍｏｌ／ｌのＬｉＰＦ_６ をエチレンカーボネートとメチルエチルカーボネートとの体積比が１：２の混合溶媒に、γ−ブチロラクトンを体積含有率で３体積％とビニレンカーボネートを体積含有率で２体積％加えて調製したものを用い、それ以外は実施例１５と同様に筒形の有機電解液電池を作製した。
【０１１９】
なお、負極活物質の比表面積は３．０ｍ^２ ／ｇであり、この負極活物質の比表面積１．０ｍ^２ ／ｇあたりのγ−ブチロラクトンの有機電解液中の体積含有率は１．０体積％であり、負極活物質の比表面積１．０ｍ^２ ／ｇあたりのビニレンカーボネートの有機電解液中の体積含有率は０．６７体積％であった。また、この電池の負極の水分量は１２５ｐｐｍであった。
【０１２０】
実施例２０
カールフィッシャー法で測定した水分量が７５ｐｐｍで負極を用いた以外は、実施例１５と同様に筒形の有機電解液電池を作製した。
【０１２１】
実施例２１
電解液として、１．２ｍｏｌ／ｌのＬｉＰＦ_６ をエチレンカーボネートとメチルエチルカーボネートとの体積比が１：２の混合溶媒に、γ−ブチロラクトンを体積含有率で７体積％加えて調製したものを用い、それ以外は実施例１５と同様に筒形の有機電解液電池を作製した。
【０１２２】
なお、負極活物質の比表面積は３．０ｍ^２ ／ｇであり、この負極活物質の比表面積１．０ｍ^２ ／ｇあたりのγ−ブチロラクトンの有機電解液中の体積含有率は２．３体積％であった。また、この電池の負極の水分量は１２５ｐｐｍであった。
【０１２３】
実施例２２
電解液として、１．２ｍｏｌ／ｌのＬｉＰＦ_６ をエチレンカーボネートとメチルエチルカーボネートの体積比が１：２の混合溶媒に、ビニレンカーボネートを体積含有率で４体積％加えて調製したものを用い、それ以外は実施例１５と同様に筒形の有機電解液電池を作製した。
【０１２４】
なお、負極活物質の比表面積は３．０ｍ^２ ／ｇであり、この負極活物質の比表面積１．０ｍ^２ ／ｇあたりのビニレンカーボネートの有機電解液中の体積含有率は１．３体積％であった。また、この電池の負極の水分量は１２５ｐｐｍであった。
【０１２５】
比較例６
負極活物質として比表面積３．０ｍ^２ ／ｇの黒鉛を９８質量部用い、Ｓ含有化合物としてのベンゼンスルホン酸リチウムやＰ含有化合物としてのリン酸リチウムを用いることなく、バインダーとしてスチレンブタジエンゴム１質量部とカルボキシメチルセルロース１質量部を水に溶解させたものを用いた以外は実施例１４と同様に負極を作製し、その負極を用いた以外は実施例１４と同様に筒形の有機電解液電池を作製した。なお、この電池の負極の水分量は１２６ｐｐｍであった。
【０１２６】
比較例７
負極活物質として比表面積３．０ｍ^２ ／ｇの黒鉛を９７質量部用い、Ｐ含有化合物としてリン酸リチウム１質量部を用い、Ｓ含有化合物としてのベンゼンスルホン酸リチウムを用いることなく、バインダーとしてスチレンブタジエンゴム１質量部とカルボキシメチルセルロース１質量部を水に溶解させたものを用い、それ以外は比較例６と同様に負極を作製し、その負極を用いた以外は実施例１４と同様に筒形の有機電解液電池を作製した。この電池の負極の水分量は１１２ｐｐｍであった。
【０１２７】
比較例８
負極活物質として比表面積３．０ｍ^２ ／ｇの黒鉛を９７．８質量部用い、Ｓ含有化合物としてベンゼンスルホン酸リチウムを０．１質量部用い、Ｐ含有化合物としてリン酸リチウムを０．１質量部用い、バインダーとしてスチレンブタジエンゴム１質量部とカルボキシメチルセルロース１質量部を水に溶解させたものを用い、それ以外は比較例６と同様に負極を作製し、その負極を用いた以外は実施例１４と同様に筒形の有機電解液電池を作製した。この電池の負極の水分量は１２８ｐｐｍであった。
【０１２８】
上記のようにして作製した実施例１４〜２２および比較例６〜８の電池について、充放電電流をＣで表示した場合、Ｒ５形で６５０ｍＡを１Ｃとして１Ｃの電流制限回路を設けて４．２Ｖの定電圧で初回充電を行い、その後、３．０Ｖまで放電した。その電池をアルゴン雰囲気のグローブボックス内で分解し、取り出した正極と負極をそれぞれメチルエチルカーボネートで１５時間浸漬洗浄し、５時間真空乾燥後、蛍光Ｘ線においてＣ、Ｏ、Ｎａ、Ｍｇ、Ａｌ、Ｓｉ、Ｓ、Ｃａ、Ｆｅ、Ｎｉ、ＣｕおよびＺｒの含有量の総和を１００質量％としたときのＳ元素の含有率ｘ（質量％）およびｙ（質量％）をそれぞれ測定した。その時の（ｘ／ｙ＝負極のＳ含有率／正極のＳ含有率）の計算結果を表３に示す。
【０１２９】
また、上記と同様の実施例１４〜２２および比較例６〜８の電池を６５０ｍＡを１Ｃとして０．１Ｃ、０．３Ｃ、０．４Ｃ、０．５Ｃ、０．６Ｃ、０．７Ｃの電流制限回路を設けて４．２Ｖの定電圧で初回充電を行った。その電池をアルゴン雰囲気のグローブボックス内で分解し、負極表面の反応ムラを観察した。表４にその結果を示す。
【０１３０】
また、上記実施例１４〜２２および比較例６〜８の電池について、０．５Ｃの電流制限回路を設けて、４．２Ｖの定電圧で初回充電した後、１Ｃの電流値で電池の電極間電圧が３．０Ｖに低下するまで放電を行った。その電池を１Ｃの電流制限回路を設けて４．２Ｖの定電圧で再び充電し、電池の電極間電圧が３．０Ｖに低下する放電する充放電を繰り返し行った。
【０１３１】
このときの電池の充放電の繰り返しにおいて、１０サイクル目に前述した条件で９０％充電を行った後、電池を室温で１日放置し、不活性雰囲気中で分解して、負極を取り出した。これを外気に触れない状態で２４時間真空乾燥後、Ｘ線光電子分光分析を行った。Ｘ線光電子分光分析は、アルバックファイ社製の「ＰＨＩ５５００ＭＣ」により、４００ＷでＡｌ−Ｋα線を用いて測定し、ピーク分割を行い、負極表面の各ピークの原子の量を算出した。その結果を表３に示す。
【０１３２】
【表３】

【０１３３】
また、実施例１４〜２２および比較例６〜８の電池について、０．５Ｃの電流制限回路を設けて４．２Ｖの定電圧で初回充電した後、電池の電極間電圧が３．０Ｖに低下するまで放電した。その電池を１Ｃの電流制限回路を設けて４．２Ｖの定電圧で再び充電し、電池の電極間電圧が３．０Ｖに低下するまで放電する充放電を繰り返した。
【０１３４】
そして、このときの電池の充放電の繰り返しにおいて、１００サイクル目に２Ｃの放電を行い、１０１サイクル目から再び１Ｃの放電を行った。この１００サイクル目の２Ｃの放電容量を、１０１サイクル目の１Ｃの放電容量で割った値に１００をかけたものを負荷特性（％）とした。表４には、その結果を負荷特性〔２Ｃ／１Ｃ（％）〕として示す。
【０１３５】
また、実施例１４〜２２および比較例６〜８の電池について、上記と同様の充放電の繰り返しにおいて、１０サイクル目に４．２Ｖの充電状態で試験を止め、その後に、１２Ｖを上限電圧として０．５Ａ、１Ａ、２Ａ、４Ａで過充電し、過充電安全電流値を測定した。その結果を表４に示す。なお、過充電安全電流値とは、電池を４．２Ｖ満充電後、１２Ｖを上限電圧として０．５Ａ、１Ａ、２Ａ、３Ａ、４Ａで過充電し、電池表面温度が１３５℃以下であった最大電流とをいう。
【０１３６】
【表４】

※ ○：反応ムラ無し、△：反応ムラ少し有り、 ×：反応ムラ有り
【０１３７】
表４に示す結果から明らかなように、実施例１４〜２２の電池は、比較例６〜８の電池に比べて、初回充電電流値を大きくしても反応ムラが生じにくいため電流値を大きくすることができ、その結果、初回充電時間を短くすることができる。また、実施例１４〜２２の電池は、貯蔵特性が優れていて、しかも、過充電安全電流が高く、過充電時の安全性も優れていた。
【０１３８】
【発明の効果】
以上説明したように、本発明によれば、その第一〜第六のいずれにおても、初回充電に要する時間を短縮でき、生産性を向上させることができる有機電解液電池を提供することができる。
【０１３９】
また、本発明において、その第六のように、電池の規格容量に対して９０％充電状態での負極表面において、Ｘ線光電子分光分析によるＣ−Ｏ由来の炭素原子に基づく２８６〜２８７ｅＶのピークから求められる炭素原子の量を６．５原子％以下にし、かつＰＯｘ由来のリンに基づく１３３〜１３５ｅＶのピークから求められるリン原子の量を１原子％以上にすることによって、前記のように、初回充電に要する時間の短縮に加えて、過充電時の安全性の高い高容量の有機電解液電池を提供することができる。
【図面の簡単な説明】
【図１】本発明の有機電解液電池の一例を模式的に示す断面図である。
【符号の説明】
１ 正極
２ 負極
３ セパレータ
４ 電解液
５ 電池ケース[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an organic electrolyte battery, and more particularly, to an organic electrolyte battery that can reduce the time required for initial charging and improve productivity.
[0002]
[Prior art]
Organic electrolyte batteries represented by lithium ion batteries have been increasingly demanded due to their high voltage and high energy density. Conventionally, an organic electrolyte battery of this type uses a carbon material, such as graphite, provided on a metal foil together with a binder on the negative electrode. ₆ And the like are dissolved in an organic solvent. However, this battery has a problem that the energy density is low.
[0003]
Then, in order to improve it, an attempt has been made to use a carbon material having a large specific surface area as a negative electrode active material. However, when a negative electrode active material having a large specific surface area is used as described above, a decomposition reaction of an organic electrolyte solution and water present in a trace amount at the time of initial charging on the negative electrode active material becomes large, and a large amount of gas is generated. . Therefore, there is a problem that gas accumulates between the electrodes and the gas hinders the reaction, resulting in uneven reaction of the electrodes. Further, the gas generation becomes more intense as the current value at the time of the first charge becomes larger, and therefore, the reaction unevenness becomes larger. Therefore, it is necessary to reduce the current value at the time of the first charge and to minimize the non-uniform reaction of the electrode due to gas generation. However, in such a case, there is a problem that a long production time is required and productivity is low.
[0004]
Therefore, an attempt has been made to suppress the generation of gas at the time of initial charging by including propane sultone in an organic electrolytic solution (for example, see Patent Document 1).
[0005]
[Patent Document 1]
JP-A-2002-170576 (page 2)
[0006]
However, when propane sultone is contained in the organic electrolytic solution, S (sulfur) more than twice as large as that of the positive electrode cannot be present in the negative electrode. Could not.
[0007]
It has also been proposed to suppress the generation of gas at the time of initial charging by including vinylene carbonate in an organic electrolyte (for example, see Patent Document 2).
[0008]
[Patent Document 2]
Japanese Patent No. 3059832 (pages 1-2)
[0009]
However, the present inventors have studied and found that gas generation during the initial charge could not be sufficiently suppressed only by adding vinylene carbonate to the organic electrolyte.
[0010]
[Problems to be solved by the invention]
An object of the present invention is to solve the problems of the conventional organic electrolyte battery as described above, and to provide an organic electrolyte battery that can reduce the time required for initial charging in a production process and improve productivity. .
[0011]
[Means for Solving the Problems]
The present invention has been made as a result of various studies to solve the above-mentioned problems. The first aspect of the present invention is an organic electrolyte battery including a negative electrode, a positive electrode, and an organic electrolyte, in which the specific surface area is 1.0 m as a negative electrode active material. ² / G or more of the lithium-containing material, and the total of the contents of C, O, Na, Mg, Al, Si, S, Ca, Fe, Ni, Cu and Zr by fluorescent X-ray analysis of the negative electrode is 100 mass %, The content x (mass%) of the S element is determined by the X-ray fluorescence analysis of C, O, Na, Mg, Al, Si, S, Ca, Fe, Ni, Cu and Zr of the positive electrode. When the total content is 100% by mass or more and is twice or more the content y (% by mass) of the S element, gas generation at the time of the first charge can be suppressed, and the time required for the first charge in the production process Was found to be shorter.
[0012]
The second aspect of the present invention relates to an organic electrolyte battery including a negative electrode, a positive electrode, and an organic electrolyte. ² / G or more of the lithium-containing material, and the total of the contents of C, O, Na, Mg, Al, Si, S, Ca, Fe, Ni, Cu and Zr by fluorescent X-ray analysis of the negative electrode is 100 mass %, The content x (mass%) of the S element is determined by the X-ray fluorescence analysis of C, O, Na, Mg, Al, Si, S, Ca, Fe, Ni, Cu and Zr of the positive electrode. More than twice the content y (% by mass) of the S element when the total content is 100% by mass, and the specific surface area of the negative electrode active material is 1.0 m ² When γ-butyrolactone is contained in an amount of 0.05 to 3% by volume in the organic electrolyte solution per g / g, gas generation at the time of initial charging can be further suppressed, and the time required for initial charging in the production process Can be further shortened.
[0013]
The third aspect of the present invention relates to an organic electrolyte battery including a negative electrode, a positive electrode, and an organic electrolyte, wherein the specific surface area of the negative electrode active material is 1.0 m ² / G or more of a lithium-containing material, and the total of the contents of C, O, Na, Mg, Al, Si, S, Ca, Fe, Ni, Cu and Zr by fluorescent X-ray analysis of the negative electrode is 100 mass%. The content x (mass%) of the S element when the content of C, O, Na, Mg, Al, Si, S, Ca, Fe, Ni, Cu and Zr was determined by fluorescent X-ray analysis of the positive electrode. More than twice the content y (% by mass) of the S element when the total amount is 100% by mass, and the specific surface area of the negative electrode active material is 1.0 m ² When the volume content of vinylene carbonate per 0.05 g / g is 0.05 to 2% by volume in the organic electrolyte solution, gas generation at the time of the first charge can be further suppressed, and the time required for the first charge in the production process can be reduced. They have found that they can be further shortened.
[0014]
In a fourth aspect of the present invention, in an organic electrolyte battery including a negative electrode, a positive electrode, and an organic electrolyte, a specific surface area as a negative electrode active material is 1.0 m. ² / G or more of the lithium-containing material, and the total of the contents of C, O, Na, Mg, Al, Si, S, Ca, Fe, Ni, Cu and Zr by fluorescent X-ray analysis of the negative electrode is 100 mass %, The content x (mass%) of the S element is determined by the X-ray fluorescence analysis of C, O, Na, Mg, Al, Si, S, Ca, Fe, Ni, Cu and Zr of the positive electrode. More than twice the content y (% by mass) of the S element when the total content is 100% by mass, and the specific surface area of the negative electrode active material is 1.0 m ² Per gram / g of γ-butyrolactone in the above-mentioned organic electrolyte at a volume content of 0.025 to 2% by volume, and vinylene carbonate in the above-mentioned organic electrolyte at a volume content of 0.025 to 1% by volume. It has been found that gas generation during initial charging can be further suppressed, and the time required for initial charging in the production process can be further reduced.
[0015]
In a fifth aspect of the present invention, in the organic electrolyte battery including the negative electrode, the positive electrode, and the organic electrolyte, the specific surface area as the negative electrode active material is 1.0 m. ² / G or more of the lithium-containing material, and the total of the contents of C, O, Na, Mg, Al, Si, S, Ca, Fe, Ni, Cu and Zr by fluorescent X-ray analysis of the negative electrode is 100 mass %, The content x (mass%) of the S element is determined by the X-ray fluorescence analysis of C, O, Na, Mg, Al, Si, S, Ca, Fe, Ni, Cu and Zr of the positive electrode. When the total amount of the content is set to at least twice the content y (% by mass) of the S element when the total content is set to 100% by mass, and when the water content of the negative electrode is set to 100 ppm or less, the time required for the first charge in the production process is further required. Can be further shortened.
[0016]
A sixth aspect of the present invention is obtained from the peak of 286 to 287 eV based on carbon atoms derived from CO by X-ray photoelectron spectroscopy on the surface of the negative electrode in a state where the battery is 90% charged with respect to the standard capacity of the battery. The first and second aspects of the present invention, in which the amount of carbon atoms is 6.5 atomic% or less, and the amount of phosphorus atoms determined from a peak of 133 to 135 eV based on POx-derived phosphorus is 1 atomic% or more. The second, third, fourth, and fifth are combined with each other, for example, when combined with the first of the invention, the sixth of the present invention is a negative electrode, a positive electrode, and an organic electrolyte. In the organic electrolyte battery containing the liquid, the specific surface area is 1.0 m as a negative electrode active material. ² / G or more of the lithium-containing material, and the total of the contents of C, O, Na, Mg, Al, Si, S, Ca, Fe, Ni, Cu and Zr by fluorescent X-ray analysis of the negative electrode is 100 mass %, The content (% by mass) of the S element is determined by the content of C, O, Na, Mg, Al, Si, S, Ca, Fe, Ni, Cu and Zr by fluorescent X-ray analysis of the positive electrode. X-ray photoelectron spectroscopy on the surface of the negative electrode at least twice the content (% by mass) of the S element when the total amount is 100% by mass and charged to 90% of the standard capacity of the battery The amount of carbon atoms determined from the peak at 286 to 287 eV based on carbon atoms derived from C—O by 6.5% by atom or less, and the amount of phosphorus atoms determined from the peak at 133 to 135 eV based on phosphorus derived from POx To 1 atomic% or more By Rukoto, suppressing gas generation during the initial charge, it is possible to shorten the time required for initial charging in the production process, it has been found that it is possible to enhance the safety during overcharge.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
In the first to sixth aspects of the present invention, the reason why gas generation during initial charging can be suppressed and the time required for initial charging in the production process can be reduced will be described in detail together with the embodiments of the present invention.
[0018]
First, the present inventor has repeatedly studied the causes of gas generation at the time of initial charging, and as a result, it has been found that gas generation at the time of initial charging is frequently generated from the negative electrode. Therefore, the present inventors have conducted intensive studies, and for example, by adding an S (sulfur) -containing compound to the negative electrode, by including an S-containing compound twice or more of the positive electrode in the fluorescent X-ray analysis, gas generation at the time of the first charge is reduced. It has been found that it can be greatly suppressed. As a result, it has been found that even if the initial charge current value is increased, the reaction unevenness of the electrodes hardly occurs, the time required for the initial charge can be shortened, and the production time can be shortened. This is because, when a negative electrode to which an S-containing compound is added is used, a film incorporating S is formed on the negative electrode active material at the time of the first charge, and the film covers the active site for solvent decomposition of the negative electrode active material, and the like. It is considered that the effect of suppressing the decomposition of the liquid solvent and suppressing the amount of generated gas is increased.
[0019]
The suppression of gas generation at the time of initial charging by including γ-butyrolactone in the organic electrolyte is also described in Japanese Patent Application No. 2002-324766 filed by the present applicant. However, the second aspect of the present invention is not limited to this. When S is present in the negative electrode more than twice as much as the positive electrode, and when a certain amount of γ-butyrolactone is contained in the organic electrolyte, the gas generation suppressing effect at the time of the first charge is obtained. Was found to be even larger. When an organic electrolyte solution containing γ-butyrolactone is used, a film in which γ-butyrolactone is reduced is formed on the negative electrode active material at the time of the first charge, and the film covers the solvent decomposition active site of the negative electrode active material. It is considered that the effect of suppressing the decomposition of the other electrolyte solution solvent and the effect of suppressing the solvent decomposition of the S-containing negative electrode coating together with the electrolyte solution solvent increase the amount of gas generated.
[0020]
In addition, it is described in Japanese Patent No. 3059832 shown as Patent Document 2 that the generation of gas at the time of the first charge can be suppressed when vinylene carbonate is contained in the organic electrolytic solution. However, as described above, simply including vinylene carbonate in the organic electrolytic solution is not sufficient in suppressing the gas generation at the time of the first charge.However, the present inventors have further studied, and in the third aspect of the present invention, The combination of a certain amount of vinylene carbonate in the organic electrolyte and the presence of more than twice the amount of S in the negative electrode as in the positive electrode makes the effect of suppressing gas generation during the first charge remarkable, Even if the value is increased, the reaction unevenness of the electrode is hardly generated.
[0021]
It is also described in Japanese Patent Application No. 2002-324766 filed by the present applicant that generation of gas at the time of initial charging can be suppressed by including γ-butyrolactone and vinylene carbonate in the organic electrolyte. However, the fourth aspect of the present invention is not limited to this, and the combination of the presence of S in the negative electrode at least twice that of the positive electrode and the inclusion of a certain amount of γ-butyrolactone and vinylene carbonate in the organic electrolyte solution, The effect of suppressing gas generation during charging was further increased.
[0022]
In the fifth aspect of the present invention, the negative electrode contains S at least twice as much as the positive electrode, and the negative electrode has a water content of 100 ppm or less, thereby decomposing a small amount of water contained in the negative electrode. The amount of hydrogen gas generated is reduced, the effect of suppressing gas generation is made more remarkable, and the effect of suppressing gas generation at the time of initial charging is made more remarkable.
[0023]
Further, in the sixth aspect of the present invention, the presence of S in the negative electrode more than twice that of the positive electrode, and the C-O by X-ray photoelectron spectroscopy on the negative electrode surface in a state of being charged 90% with respect to the standard capacity of the battery. By combining the amount of carbon atoms determined from the peak at 286 to 287 eV based on the carbon atoms derived from PO and the amount of phosphorus atoms determined from the peak at 133 to 135 eV based on phosphorus derived from POx, Thus, the time required for the first charge in the production process can be reduced by suppressing the generation of gas at the time of, and the safety at the time of overcharge is enhanced.
[0024]
Specifically, in the first aspect of the present invention, in an organic electrolyte battery including a negative electrode, a positive electrode, and an organic electrolyte, a specific surface area as a negative electrode active material is 1.0 m ² / G or more of the lithium-containing material, and the total of the contents of C, O, Na, Mg, Al, Si, S, Ca, Fe, Ni, Cu and Zr by fluorescent X-ray analysis of the negative electrode is 100 mass %, The content x (mass%) of the S element is determined by the X-ray fluorescence analysis of C, O, Na, Mg, Al, Si, S, Ca, Fe, Ni, Cu and Zr of the positive electrode. By making it twice or more the S element content y (% by mass) when the total content is 100% by mass, it is possible to suppress gas generation at the time of the first charge, and to suppress the occurrence of reaction unevenness in the electrode. Therefore, the charging current value was increased, and the production speed was improved.
[0025]
Further, when the total content of C, O, Na, Mg, Al, Si, S, Ca, Fe, Ni, Cu and Zr by fluorescent X-ray analysis of the negative electrode is 100% by mass, The content x (mass%) is defined as 100 mass% of the sum of the contents of C, O, Na, Mg, Al, Si, S, Ca, Fe, Ni, Cu and Zr by fluorescent X-ray analysis of the positive electrode. It is more preferable to set the content of the element S to 3 to 10 times the content y (mass%) of the above, since the effect of suppressing gas generation at the time of the first charge is further increased and the effect of improving the production speed is further increased.
[0026]
However, in an organic electrolyte battery including a negative electrode, a positive electrode, and an organic electrolyte, the specific surface area of the negative electrode active material is 1.0 m ² / G or more of the lithium-containing material, and the total of the contents of C, O, Na, Mg, Al, Si, S, Ca, Fe, Ni, Cu and Zr by fluorescent X-ray analysis of the negative electrode is 100 mass %, The content x (mass%) of the S element is determined by the fluorescence X-ray analysis of the positive electrode of C, O, Na, Mg, Al, Si, S, Ca, Fe, Ni, Cu and Zr. If the total amount of the content is less than twice the content y (% by mass) of the S element when the total content is 100% by mass, the gas generation suppression effect at the time of the first charge is small, and the charge current value at the first charge is increased. Production speed is hardly improved.
[0027]
Further, when the total content of C, O, Na, Mg, Al, Si, S, Ca, Fe, Ni, Cu and Zr by fluorescent X-ray analysis of the negative electrode is 100% by mass, The content x (mass%) is 100 mass% of the sum of the contents of C, O, Na, Mg, Al, Si, S, Ca, Fe, Ni, Cu and Zr by fluorescent X-ray analysis of the positive electrode. If the content is 11 times or more of the content y (mass%) of the S element at the time, the load characteristics tend to slightly decrease.
[0028]
Next, in a second embodiment of the present invention, in the first organic electrolyte battery of the present invention including the negative electrode, the positive electrode, and the organic electrolyte, in addition to the first requirement, the specific surface area of the negative electrode active material is 1 .0m ² The content of γ-butyrolactone in the organic electrolyte solution was 0.05 to 3% by volume per g / g to further enhance the gas generation suppression effect at the time of the first charge, thereby further improving the production speed. . It is more preferable that the volume content of γ-butyrolactone in the organic electrolyte be 0.2 to 3% by volume, because the effect of suppressing gas generation at the time of the first charge is further increased and the effect of improving the production speed is further increased. 1.0m specific surface area of negative electrode active material ² When the volume content of γ-butyrolactone in the organic electrolyte solution per g / g is less than 0.05% by volume, the effect of further suppressing the generation of gas at the time of first charge is reduced, and the organic content of γ-butyrolactone is reduced. When the volume content in the electrolytic solution exceeds 3% by volume, the load characteristics tend to slightly decrease.
[0029]
Next, in a third aspect of the present invention, in the first organic electrolyte battery of the present invention including the negative electrode, the positive electrode, and the organic electrolyte, the specific surface area of the negative electrode active material is 1.0 m ² The content of vinylene carbonate per 0.05 g / g was contained in the organic electrolyte solution in a volume content of 0.05 to 2% by volume, whereby the effect of suppressing gas generation at the time of the first charge was further increased, and the production speed was further improved. . 1.0m specific surface area of negative electrode active material ² When the volume content of vinylene carbonate per 0.1 g / g is 0.1 to 2% by volume in the organic electrolyte, the effect of suppressing gas generation at the time of the first charge is increased, and the effect of improving the production speed is further increased. Is more preferable. 1.0m specific surface area of negative electrode active material ² If the volume content of vinylene carbonate in the organic electrolyte per g / g is less than 0.05% by volume, the effect of further suppressing the generation of gas at the time of the first charge is reduced, and the content of vinylene carbonate is reduced. When the volume content in the organic electrolyte exceeds 2% by volume, the load characteristics tend to decrease.
[0030]
According to a fourth aspect of the present invention, in the first organic electrolyte battery of the present invention including the negative electrode, the positive electrode, and the organic electrolyte, the specific surface area of the negative electrode active material is 1.0 m ² / G per volume of γ-butyrolactone in the organic electrolyte solution per 0.025 to 2% by volume, and a specific surface area of the negative electrode active material of 1.0 m ² The content of vinylene carbonate in the organic electrolyte solution was 0.025 to 1% by volume per 1 g / g to further suppress the gas generation at the time of the first charge, thereby further improving the production speed. .
[0031]
In the fourth organic electrolyte battery of the present invention including the negative electrode, the positive electrode, and the organic electrolyte, the specific surface area is 1.0 m as the negative electrode active material. ² / G or more of the lithium-containing material, and the specific surface area of the negative electrode active material is 1.0 m ² / G per volume of γ-butyrolactone in the organic electrolytic solution, and a specific surface area of 1.0 m of the negative electrode active material. ² When vinylene carbonate is contained in an amount of 0.2 to 1% by volume in the organic electrolyte solution per 1 g / g, the effect of suppressing gas generation at the time of the first charge is increased, and the effect of improving the production speed is increased. More preferred. In the fourth organic electrolyte battery according to the present invention, the specific surface area of the negative electrode active material is 1.0 m. ² The content of γ-butyrolactone per g / g is less than 0.025% by volume in the organic electrolytic solution, or the specific surface area of the negative electrode active material is 1.0 m ² When the volume content of vinylene carbonate per g / g is less than 0.025% by volume in the organic electrolyte, the gas generation suppressing effect at the time of the first charge is further reduced, and the ratio of the negative electrode active material is reduced. Surface area 1.0m ² / G of γ-butyrolactone in the organic electrolyte is greater than 2% by volume, or the specific surface area of the negative electrode active material is 1.0 m ² If the volume content of vinylene carbonate per 1 g / g is more than 1% by volume in the organic electrolyte solution, the capacity under a high load tends to decrease.
[0032]
In the fifth aspect of the present invention, the negative electrode, the positive electrode, and the first organic electrolyte battery of the present invention containing an organic electrolyte, the negative electrode having a water content of 100 ppm or less, the water content of the negative electrode active material surface The generation of hydrogen gas due to reductive decomposition was suppressed, and the gas generation during the first charge was further suppressed. As a result, the current value at the time of the first charge can be further increased, and the production speed can be further improved. The water content of the negative electrode taken out of the battery is preferably as small as possible, as described above, preferably 100 ppm or less, more preferably 80 ppm or less, and even more preferably less than 80 ppm. Further, when the water content of the negative electrode is more than 100 ppm, the effect of further improving the production speed is reduced.
[0033]
According to a sixth aspect of the present invention, in each of the first to fifth organic electrolyte batteries of the present invention including the negative electrode, the positive electrode, and the organic electrolyte, the negative electrode in a 90% charged state with respect to the standard capacity of the battery. On the surface, the amount of carbon atoms determined from the peak of 286 to 287 eV based on carbon atoms derived from CO by X-ray photoelectron spectroscopy is reduced to 6.5 atom% or less, and the amount of 133 to 135 eV based on phosphorus derived from POx is reduced. By setting the amount of phosphorus atoms obtained from the peak to 1 atomic% or more, gas generation during initial charging is suppressed, the time required for initial charging in the production process is reduced, and safety during overcharging is reduced. It was raised.
[0034]
In the sixth aspect of the present invention, the X-ray photoelectron spectroscopy analysis is performed by charging the battery to 90% of the standard capacity, leaving it for one day, decomposing it in an inert atmosphere, taking out the negative electrode, vacuum drying for 24 hours, The measurement was performed by measuring the photoelectron spectrum of the surface of the negative electrode without touching the surface.
[0035]
In the sixth aspect of the present invention, the amount of carbon atoms determined by X-ray photoelectron spectroscopy was measured using a PHI5500MC manufactured by ULVAC-PHI, Inc. at 400 W using A1-Kα radiation, and peak splitting was performed. Then, the amount of atoms at each peak on the negative electrode surface was calculated as a ratio (%) of all constituent atoms. Here, the “all constituent atoms” means all the atoms forming the surface portion of the negative electrode, that is, all the atoms forming the SEI (Solid Electrolyle Interface) coating.
[0036]
In the sixth aspect of the present invention, although the amount of phosphorus atoms determined from the peak of 133 to 135 eV based on phosphorus derived from POx is 1 atomic% or more, the effect of suppressing gas generation during the first charge can be obtained. Although the reason for this is not always clear at present, it is considered that stabilizing a substance which easily reacts with the solvent on the surface of the negative electrode active material by reacting with phosphorus suppresses decomposition of the electrolytic solution.
[0037]
In the sixth aspect of the present invention, the reason why the safety at the time of overcharging is improved is not always clear at present, but is considered as follows. When the conventional battery is disassembled and the surface of the negative electrode is observed by X-ray photoelectron spectroscopy, a peak based on carbon atoms is confirmed in the range of 286 to 287 eV. The negative electrode surface in the charged state is Li ₂ O, LiF, Li ₂ CO ₃ , An alkoxide, an alkyl carbonate, or the like, which is known to be covered with an SEI (Solid Electrolyle Interface) film, thereby preventing an excessive side reaction between the electrolyte and the negative electrode. The peak is considered to be a peak derived from alkoxide which is a constituent component of the SEI coating, that is, a peak based on carbon atoms derived from CO. The present inventors have focused on alkoxides, particularly low-molecular-weight alkoxides, from which the above-mentioned peaks are derived, and this is inferior in stability to an electrolytic solution at a high temperature, so that the temperature of the battery increases during a safety test such as overcharging. If this occurs, the SEI coating is degraded, and in particular, when a negative electrode active material having a large specific surface area is used, heat generated by a new reaction between the electrolyte and the negative electrode is increased, and the safety of the battery is reduced. . In order to solve this problem, the present inventors treated the negative electrode active material and the negative electrode using the same with phosphoric acid or phosphate to replace the lithium in the alkoxide with phosphorus, thereby reducing the amount of the SEI film. It has been found that, when a certain amount of phosphorus atoms derived from phosphorus (POx) are bonded, deterioration of the SEI film at high temperatures can be suppressed, and safety during overcharge can be improved.
[0038]
In the sixth aspect of the present invention, the amount of phosphorus atoms determined from a peak of 133 to 135 eV based on phosphorus derived from POx on the negative electrode surface in a 90% charged state with respect to the standard capacity of the battery is set to 1 atomic% or more. Is a method in which the negative electrode active material or the negative electrode is immersed and dried in a solution of phosphoric acid or phosphate for a certain period of time, and a method in which the solution of phosphoric acid or phosphate is mixed into a paint containing the negative electrode active material, a binder, and the like when preparing the negative electrode And a method of adding it to the electrolytic solution.
[0039]
In the sixth aspect of the present invention, the standard capacity of the battery is determined as follows. When charging at a constant current at 20 ° C. with the battery voltage at the start of charging being 3.5 V, the time required for the battery voltage to reach 4.2 V is in the range of 1.5 to 2 hours. The battery is charged to 4.2 V at the current value, and then charged at a constant voltage of 4.2 V for 3 hours. Next, discharging is performed at the above current value, and the discharge capacity until the battery voltage decreases to 3.0 V is defined as a standard capacity. The 90% charge state is defined as the state when the battery is charged at 20 ° C., the voltage of the battery at the start of charging is 3.5 V, and the battery is charged at a current value of 1 C for 0.9 hours when the standard capacity is 1 C. Say. In the sixth aspect of the present invention, the battery is set to a 90% charge state instead of a 100% charge state with respect to the standard capacity of the battery, because the battery does not reach the standard capacity after repeated charge / discharge cycles or after high-temperature storage. Charging may not be possible.
[0040]
In the sixth aspect of the present invention, by adopting the above configuration, an organic electrolyte battery having high productivity and high safety during overcharge can be obtained. If the amount of Pt is more than 6.5 atomic% or the amount of the above-mentioned POx-derived phosphorus atoms is less than 1 atomic%, the stability of the SEI coating on the negative electrode surface at high temperature is reduced, and the safety at the time of overcharge is reduced descend.
[0041]
In the sixth aspect of the present invention, in order to further enhance the safety at the time of overcharging, the negative electrode in a charged state of 90% of the standard capacity of the battery is derived from CO by X-ray photoelectron spectroscopy. The amount of carbon atoms determined from the peak of 286 to 287 eV based on the carbon atom of the above is set to 6.0 atomic% or less, and the amount of phosphorus atoms determined from the peak of 133 to 135 eV based on the phosphorus derived from POx is reduced to 1.5 atomic%. More preferably, it is more preferably at least 2 atomic%. Although the amount of the phosphorus atoms derived from POx may be large, when it is added to the paste, if it is too large, the active material ratio tends to decrease and the capacity tends to decrease. preferable.
[0042]
In the present invention, the specific surface area of the negative electrode active material is 1.0 m. ² / G or more of a lithium-containing material. Examples of the lithium-containing material include carbon materials having a turbostratic structure, natural graphite, artificial graphite, and glassy carbon. Some of them do not contain lithium at the time of manufacture, but when they act as a negative electrode active material, they become lithium-containing by chemical means or electrochemical means. In addition, as the lithium-containing material as the negative electrode active material, for example, lithium metal or a lithium-containing compound is used, and as the lithium-containing compound, there are a lithium alloy and others, and as the lithium alloy, For example, alloys of lithium and other metals such as lithium-aluminum, lithium-lead, lithium-bismuth, lithium-indium, lithium-gallium, lithium-indium-gallium, and the like can be given.
[0043]
In the present invention, the specific surface area of the negative electrode active material is 1.0 m ² / G or more, in order to improve the energy density of the battery. The specific surface area of the negative electrode active material is preferably as large as possible. ² / G is suitable for use.
[0044]
In the present invention, as the S-containing compound to be contained in the negative electrode, for example, lithium benzenesulfonate, lithium sulfate, CF ₃ SO ₃ Li, CH ₃ SO ₃ Li, Li ₂ S, P ₂ S ₃ , P ₄ S ₁₀ , (CH ₃ ) ₂ SO ₂ , (C ₂ H ₅ O) ₂ SO ₂ , Sulfolane and the like are used. As described above, this S-containing compound is contained in the negative electrode such that the content x (% by mass) of the S element in the negative electrode is twice or more the content y (% by mass) of the S element in the positive electrode. Usually, the content may be about 0.1 to 5% by mass in the negative electrode mixture constituting the coating film of the negative electrode.
[0045]
The negative electrode, for example, to the negative electrode active material, the above-mentioned S-containing compound, and, if necessary, for example, flaky graphite, an electron conduction aid such as carbon black, and a binder and a solvent are added and mixed. It is prepared through a process of preparing a paint, applying the paint to a conductive substrate also serving as a negative electrode current collector, and drying and forming a coating film. In preparing the paint, it is preferable to use the binder as a solution previously dissolved in an organic solvent, water, an aqueous solution, or the like, and to mix it with solid particles such as the negative electrode active material to prepare the paint.
[0046]
In the present invention, as the positive electrode active material, for example, lithium nickel oxide, lithium cobalt oxide, lithium manganese oxide (these are usually LiNiO ₂ , LiCoO ₂ , LiMn ₂ O ₄ Where the ratio of Li to Ni, the ratio of Li to Co, and the ratio of Li to Mn often deviate somewhat from the stoichiometric composition, but may deviate as such). The lithium-containing composite oxide can be used alone or as a mixture of two or more thereof, or as a solid solution thereof.
[0047]
The positive electrode includes, for example, the above-described positive electrode active material, optionally includes flaky graphite, an electron conduction aid such as carbon black, and further applies a coating material containing a binder on a conductive substrate as a positive electrode current collector. , And dried to form a coating film.
[0048]
As the binder, for example, a polyvinylidene fluoride-based polymer (a polymer of a fluorine-containing monomer group containing at least 80% by mass of vinylidene fluoride as a main component monomer), a rubber-based polymer, or a cellulose-based polymer is preferable. The above polymers may be used as a mixture.
[0049]
Examples of the fluorine-containing monomer group containing at least 80% by mass of vinylidene fluoride as the main component monomer include vinylidene fluoride alone or a mixture of vinylidene fluoride and at least one other monomer. Examples of the other monomers include vinylidene fluoride, trifluoroethylene, trifluorochloroethylene, tetrafluoroethylene, hexafluoropropylene, and fluoroalkyl vinyl ether.
[0050]
Examples of the rubber-based polymer include carboxymethylcellulose, methylcellulose, ethylcellulose, hydroxypropylcellulose, hydroxyethylmethylcellulose, and hydroxypropylmethylcellulose.
[0051]
In the present invention, the content of the binder in the coating film is preferably 0.2 to 20% by mass, and particularly preferably 0.5 to 10% by mass. When the content of the binder is less than the above range, the mechanical strength of the coating film is insufficient, the coating film may be peeled off from the conductive substrate, and when the content of the binder is more than the above range, There is a possibility that the active material in the coating film decreases and the battery capacity decreases.
[0052]
In the present invention, as a coating method for applying the coating material to the conductive substrate of the positive electrode or the negative electrode, for example, an extrusion coater, a reverse roller, a doctor blade, an applicator, and the like, various application methods can be adopted. .
[0053]
As the conductive substrate of the positive electrode or the negative electrode, for example, a net, punched metal, foam metal, or a plate-shaped foil of a metal conductive material such as aluminum, stainless steel, titanium, or copper is used.
[0054]
The organic electrolyte solution is prepared by dissolving an electrolyte in an organic solvent. As the organic solvent, for example, 1,2-dimethoxyethane, 1,2-diethoxyethane, dimethoxypropane, Ethers such as 1,3-dioxolane, tetrahydrofuran and 2-methyltetrahydrofuran; esters such as propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate and ethylmethyl carbonate; and single or mixed solvents such as sulfolane Can be used. Among them, esters are preferable because they have little reactivity with the positive electrode active material even under a high voltage and have a large effect of improving storage characteristics. It is preferable that this ester accounts for 30% by volume or more of the total organic solvent. In the present invention, γ-butyrolactone and / or vinylene carbonate are further contained in the main solvent, if necessary, as described above.
[0055]
As the electrolyte to be dissolved in the organic solvent, for example, a general formula LiMF _n Wherein M is P, As, Sb or B, and n is 6 when M is P, As or Sb, and 4 when M is B. Fluoroorganic lithium imide salts and the like can be used, each of which can be used alone or in combination of two or more. The electrolyte concentration is preferably from 0.4 to 1.6 mol / l as a whole, especially from 0.6 to 1.4 mol / l, even if two or more different electrolytes are contained. Is preferred.
[0056]
As the separator, for example, a microporous polyethylene film, a microporous polypropylene film, a microporous ethylene-propylene copolymer film having a thickness of 10 to 50 μm and a porosity of 30 to 70% is preferably used.
[0057]
The battery is, for example, a sheet-shaped positive electrode manufactured as described above, and a spirally wound electrode body or a laminated electrode body that is manufactured by spirally winding with a separator interposed between the sheet-shaped negative electrode, and nickel. It is inserted into a battery case made of plated iron or stainless steel, injected with an electrolyte, and sealed. Further, the battery usually incorporates an explosion-proof mechanism for discharging gas generated inside the battery to the outside of the battery at a stage when the pressure has risen to a certain constant pressure, thereby preventing the battery from bursting under high pressure.
[0058]
【Example】
Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to only these examples.
[0059]
Example 1
A negative electrode was prepared as follows.
First, the specific surface area of the negative electrode active material was 3.0 m. ² / G of graphite, 97 parts by mass of graphite, 1 part by mass of lithium benzenesulfonate as the S-containing compound, and 1 part by mass of styrene-butadiene rubber and 1 part by mass of carboxymethylcellulose dissolved in water as a binder. All of the above were mixed to prepare a negative electrode coating film forming paint.
[0060]
The obtained paint was applied on a conductive substrate made of a copper foil having a thickness of 10 μm using an applicator, and dried at 100 ° C. to form a coating film. The paint was also applied to the back side of the conductive substrate made of the copper foil and dried to prepare an electrode body. Thereafter, the electrode body was vacuum-dried at 100 ° C. for 10 hours and roll-pressed to obtain a sheet-shaped negative electrode. The coating density of this negative electrode is 1.5 g / cm ³ Met. The water content of the negative electrode measured by the Karl Fischer method was 120 ppm. The amount of water in the negative electrode was measured by cutting the negative electrode into test pieces of 2 cm × 5 cm, heating the mixture to 170 ° C., and introducing the water vapor discharged into a Karl Fischer apparatus. The above water content was expressed as the mass of water in the negative electrode with respect to the mass of the coating film.
[0061]
A positive electrode was prepared as follows.
95 parts by mass of lithium cobalt oxide, 1 part by mass of carbon black as an electron conduction aid, 1 part by mass of flake graphite, and 3 parts by mass of polyvinylidene fluoride as a binder were N-methyl-2-pyrrolidone. Was used to prepare a coating for forming a positive electrode coating system. The preparation of the paint was performed as follows. First, a binder solution was prepared by dissolving polyvinylidene fluoride in N-methyl-2-pyrrolidone. Next, lithium cobalt oxide as a positive electrode active material, carbon black and flaky graphite as electron conduction aids were added to the binder solution, and mixed to prepare a coating material.
[0062]
And the obtained paint was apply | coated using the applicator on the conductive base which consists of a 15-micrometer-thick aluminum foil, and it dried at 100-120 degreeC, and formed the coating film. Similarly, the paint was applied and dried on the back side of the conductive substrate made of the aluminum foil to form an electrode body. The electrode body was vacuum-dried at 100 ° C. for 10 hours and roll-pressed to obtain a sheet-shaped positive electrode. The coating density of this positive electrode is 3.30 g / cm. ³ Met.
[0063]
1.2 mol / l LiPF as electrolyte ₆ Was dissolved in a mixed solvent having a volume ratio of ethylene carbonate and methyl ethyl carbonate of 1: 2.
[0064]
The assembly of the cylindrical organic electrolyte battery was performed as follows.
First, the above-mentioned sheet-like negative electrode was cut into a strip having a width of 28 mm × length of 220 mm, and the above-mentioned sheet-like negative electrode was cut into a strip having a width of 30 mm × length of 260 mm. A part of the coating film at each electrode end was peeled off, and an aluminum lead body was resistance-welded to a portion where the metal foil was exposed. A strip-shaped separator made of a microporous polypropylene film having a thickness of 20 μm and a porosity of 50% was interposed between the sheet-shaped positive electrode and the sheet-shaped negative electrode, and spirally wound to produce a spirally wound electrode body.
[0065]
Next, the spirally wound electrode body thus manufactured was inserted into a bottomed cylindrical battery case, and the positive electrode lead body and the negative electrode lead body were welded. Then, after injecting 2 ml of the organic electrolyte in a dry atmosphere, the container was sealed, and a cylindrical R5 type organic electrolyte battery (outer diameter: 14.95 mm, height: 39.7 mm) shown in FIG. 1 was produced. .
[0066]
Referring to the battery shown in FIG. 1, 1 is the positive electrode and 2 is the negative electrode. However, FIG. 1 does not show a metal foil or the like as a conductive substrate used in manufacturing the positive electrode 1 or the negative electrode 2 in order to avoid complication. Reference numeral 3 denotes a separator. The positive electrode 1 and the negative electrode 2 are spirally wound through the separator 3 and are housed in a battery case 5 together with the above-mentioned specific organic electrolyte solution 4 as a spiral electrode body.
[0067]
The battery case 5 is made of iron and nickel-plated on the surface, and an insulator 6 made of polypropylene is arranged on the bottom of the battery case 5 before the spiral electrode body is inserted. The sealing plate 7 is made of aluminum and has a disk shape, provided with a thin portion 7a at the center thereof, and as a pressure introduction port 7b around the thin portion 7a for allowing the battery internal pressure to act on the explosion-proof valve 9. Holes are provided. The projection 9a of the explosion-proof valve 9 is welded to the upper surface of the thin portion 7a to form a welded portion 11. Note that the thin portion 7a provided on the sealing plate 7 and the protruding portion 9a of the explosion-proof valve 9 and the like only show the cut surface for easy understanding in the drawings. Is not shown. Also, the welded portion 11 between the thin portion 7a of the sealing plate 7 and the protruding portion 9a of the explosion-proof valve 9 is shown in an exaggerated state in order to facilitate understanding in the drawings.
[0068]
The terminal plate 8 is made of a rolled steel, nickel-plated on its surface, and has a hat-like shape with a peripheral edge formed in a flange shape. The terminal plate 8 is provided with a gas outlet 8a. The explosion-proof valve 9 is made of aluminum and has a disk shape. A projection 9a having a tip portion is provided at a center portion of the explosion-proof valve 9 on the power generation element side (the lower side in FIG. 1), and a thin portion 9b is provided. As described above, the lower surface of the projecting portion 9a is welded to the upper surface of the thin portion 7a of the sealing plate 7 to form a welded portion 11. The insulating packing 10 is made of polypropylene and has an annular shape. The insulating packing 10 is disposed above the peripheral edge of the sealing plate 7, and the explosion-proof valve 9 is disposed above the insulating packing 10. The insulating packing 10 insulates the sealing plate 7 from the explosion-proof valve 9. A gap is sealed between the two so that the organic electrolyte does not leak from between the two. The annular gasket 12 is made of polypropylene, the lead body 13 is made of aluminum, connects the sealing plate 7 and the positive electrode 1, an insulator 14 is disposed on the spiral electrode body, and the negative electrode 2 and the battery case 5 The bottom is connected by a lead body 15 made of nickel.
[0069]
In this battery, the thin portion 7a of the sealing plate 7 and the protruding portion 9a of the explosion-proof valve 9 make contact at the welded portion 11, the peripheral portion of the explosion-proof valve 9 contacts the peripheral portion of the terminal plate 8, and the positive electrode 1 Since the positive electrode 1 and the terminal plate 8 are electrically connected to the sealing plate 7 by the lead 13, the sealing plate 7, the explosion-proof valve 9, and their welded portions 11 in a normal state, the lead 1 is connected to the sealing plate 7. The electrical connection is obtained and functions normally as an electric circuit.
[0070]
When an abnormal situation occurs in the battery, such as when the battery is exposed to high temperature or generates heat due to overcharging, and gas is generated inside the battery to increase the internal pressure of the battery, the internal pressure rises to cause an explosion-proof valve 9. Is deformed in the direction of the internal pressure (upward direction in FIG. 1), and along with this, a shearing force acts on the thin portion 7a of the sealing plate 7 integrated by the welding portion 11, and the thin portion 7a is broken. Alternatively, after the welding portion 11 between the projection 9a of the explosion-proof valve 9 and the thin portion 7a of the sealing plate 7 is peeled off, the thin portion 9b provided on the explosion-proof valve 9 is torn and gas is released from the terminal plate 8. The battery is designed to be able to be discharged to the outside of the battery from the gas discharge port 8a to prevent the battery from bursting.
[0071]
Example 2
3.0 m specific surface area as negative electrode active material ² / G of graphite was used in an amount of 98.5 parts by mass, lithium benzenesulfonate was used as an S-containing compound in an amount of 0.5 part by mass, and 1 part by mass of styrene butadiene rubber and 1 part by mass of carboxymethyl cellulose were dissolved in water as a binder. A negative electrode was produced in the same manner as in Example 1 except for the above. The water content of the negative electrode was 128 ppm. A cylindrical organic electrolyte battery was manufactured in the same manner as in Example 1 except that the negative electrode was used.
[0072]
Example 3
3.0 m specific surface area as negative electrode active material ² / G of graphite, 95 parts by mass of graphite, 3 parts by mass of lithium benzenesulfonate as the S-containing compound, and a binder obtained by dissolving 1 part by mass of styrene butadiene rubber and 1 part by mass of carboxymethyl cellulose in water, Otherwise, a negative electrode was produced in the same manner as in Example 1. The water content of the negative electrode was 124 ppm. A cylindrical organic electrolyte battery was manufactured in the same manner as in Example 1 except that the negative electrode was used.
[0073]
Example 4
1.2 mol / l LiPF as electrolyte ₆ Was prepared by adding γ-butyrolactone at a volume content of 3% by volume to a mixed solvent having a volume ratio of ethylene carbonate and methyl ethyl carbonate of 1: 2. Was manufactured.
[0074]
The specific surface area of the negative electrode active material was 3.0 m. ² / G, the specific surface area of the negative electrode active material is 1.0 m ² / G of γ-butyrolactone in the organic electrolyte was 1.0% by volume.
[0075]
Example 5
1.2 mol / l LiPF as electrolyte ₆ Prepared by adding γ-butyrolactone at a volume content of 0.2% by volume to a mixed solvent having a volume ratio of ethylene carbonate and methyl ethyl carbonate of 1: 2, except that the same as in Example 1 A cylindrical organic electrolyte battery was manufactured.
[0076]
The specific surface area of the negative electrode active material was 3.0 m. ² / G, the specific surface area of the negative electrode active material is 1.0 m ² The volume content of γ-butyrolactone in the organic electrolyte per g / g was 0.067% by volume.
[0077]
Example 6
1.2 mol / l LiPF as electrolyte ₆ Prepared by adding γ-butyrolactone at a volume content of 7% by volume to a mixed solvent having a volume ratio of ethylene carbonate and methyl ethyl carbonate of 1: 2. An organic electrolyte battery was manufactured.
[0078]
The specific surface area of the negative electrode active material was 3.0 m. ² / G, the specific surface area of the negative electrode active material is 1.0 m ² The volume content of γ-butyrolactone in the organic electrolyte per g / g was 2.3% by volume.
[0079]
Example 7
1.2 mol / l LiPF as electrolyte ₆ Prepared by adding vinylene carbonate at a volume content of 2% by volume to a mixed solvent having a volume ratio of ethylene carbonate and methyl ethyl carbonate of 1: 2. An electrolyte battery was manufactured.
[0080]
The specific surface area of the negative electrode active material was 3.0 m. ² / G, the specific surface area of the negative electrode active material is 1.0 m ² Per volume / g of vinylene carbonate in the organic electrolyte was 0.67% by volume.
[0081]
Example 8
1.2 mol / l LiPF as electrolyte ₆ Prepared by adding vinylene carbonate at a volume content of 0.2% by volume to a mixed solvent having a volume ratio of ethylene carbonate and methyl ethyl carbonate of 1: 2. An organic electrolyte battery was manufactured.
[0082]
The specific surface area of the negative electrode active material was 3.0 m. ² / G, the specific surface area of the negative electrode active material is 1.0 m ² Per volume / g of vinylene carbonate in the organic electrolyte was 0.067% by volume.
[0083]
Example 9
1.2 mol / l LiPF as electrolyte ₆ Prepared by adding vinylene carbonate at a volume content of 4% by volume to a mixed solvent having a volume ratio of ethylene carbonate and methyl ethyl carbonate of 1: 2. An electrolyte battery was manufactured.
[0084]
The specific surface area of the negative electrode active material was 3.0 m. ² / G, the specific surface area of the negative electrode active material is 1.0 m ² Per volume / g of vinylene carbonate in the organic electrolyte was 1.3% by volume.
[0085]
Example 10
1.2 mol / l LiPF as electrolyte ₆ Was prepared by adding γ-butyrolactone at a volume content of 3% by volume and vinylene carbonate at a volume content of 2% by volume to a mixed solvent having a volume ratio of ethylene carbonate and methyl ethyl carbonate of 1: 2, Otherwise, a tubular organic electrolyte battery was manufactured in the same manner as in Example 1.
[0086]
The specific surface area of the negative electrode active material was 3.0 m. ² / G, the specific surface area of the negative electrode active material is 1.0 m ² The volume content of vinylene carbonate in the organic electrolyte per 1 g / g was 1.0 volume%, and the volume content of vinylene carbonate in the organic electrolyte was 0.67 volume%.
[0087]
Example 11
1.2 mol / l LiPF as electrolyte ₆ Was prepared by adding 0.2% by volume of γ-butyrolactone and 0.2% by volume of vinylene carbonate to a mixed solvent having a volume ratio of ethylene carbonate and methyl ethyl carbonate of 1: 2. A cylindrical organic electrolyte battery was produced in the same manner as in Example 1 except for the above.
[0088]
The specific surface area of the negative electrode active material was 3.0 m. ² / G, the specific surface area of the negative electrode active material is 1.0 m ² The volume content of γ-butyrolactone in the organic electrolyte solution per g / g was 0.033% by volume, and the volume content of vinylene carbonate in the organic electrolyte solution was 0.033% by volume.
[0089]
Example 12
1.2 mol / l LiPF as electrolyte ₆ Was prepared by adding γ-butyrolactone at a volume content of 7% by volume and vinylene carbonate at a volume content of 4% by volume to a mixed solvent having a volume ratio of ethylene carbonate and methyl ethyl carbonate of 1: 2, Otherwise, a tubular organic electrolyte battery was manufactured in the same manner as in Example 1.
[0090]
The specific surface area of the negative electrode active material was 3.0 m. ² / G, the specific surface area of the negative electrode active material is 1.0 m ² The volume content of γ-butyrolactone in the organic electrolyte per 2 g / g was 2.3% by volume, and the volume content of vinylene carbonate in the organic electrolyte was 1.3% by volume.
[0091]
Example 13
A cylindrical organic electrolyte battery was produced in the same manner as in Example 1, except that the negative electrode was used at a water content of 75 ppm measured by the Karl Fischer method.
[0092]
Comparative Example 1
3.0 m specific surface area as negative electrode active material ² / G of graphite was used in an amount of 98 parts by mass, and without using lithium benzenesulfonate as an S-containing compound, a binder prepared by dissolving 1 part by mass of styrene-butadiene rubber and 1 part by mass of carboxymethyl cellulose in water was used as a binder. A negative electrode was produced in the same manner as in Example 1, and a cylindrical organic electrolyte battery was produced in the same manner as in Example 1 except that the negative electrode was used.
[0093]
Comparative Example 2
1.2 mol / l LiPF as electrolyte ₆ Was prepared by adding propane sultone at a volume content of 2% by volume to a mixed solvent having a volume ratio of ethylene carbonate and methyl ethyl carbonate of 1: 2. An electrolyte battery was manufactured.
[0094]
Comparative Example 3
1.2 mol / l LiPF as electrolyte ₆ Was prepared by adding γ-butyrolactone at a volume content of 3% by volume to a mixed solvent having a volume ratio of ethylene carbonate and methyl ethyl carbonate of 1: 2. An electrolyte battery was manufactured.
[0095]
The specific surface area of the negative electrode active material was 3.0 m. ² / G, the specific surface area of the negative electrode active material is 1.0 m ² / G of γ-butyrolactone in the organic electrolyte was 1.0% by volume.
[0096]
Comparative Example 4
1.2 mol / l LiPF as electrolyte ₆ Prepared by adding vinylene carbonate at a volume content of 2% by volume to a mixed solvent having a volume ratio of ethylene carbonate and methyl ethyl carbonate of 1: 2. An electrolyte battery was manufactured.
[0097]
The specific surface area of the negative electrode active material was 3.0 m. ² / G, the specific surface area of the negative electrode active material is 1.0 m ² Per volume / g of vinylene carbonate in the organic electrolyte was 0.67% by volume.
[0098]
Comparative Example 5
1.2 mol / l LiPF as electrolyte ₆ Prepared by adding γ-butyrolactone at a volume content of 3% by volume and vinylene carbonate at a volume ratio of 2% by volume to a mixed solvent having a volume ratio of ethylene carbonate and methyl ethyl carbonate of 1: 2. A cylindrical organic electrolyte battery was manufactured in the same manner as in Comparative Example 1 except for the above.
[0099]
The specific surface area of the negative electrode active material was 3.0 m. ² / G, the specific surface area of the negative electrode active material is 1.0 m ² The volume content of vinylene carbonate in the organic electrolyte per 1 g / g was 1.0 volume%, and the volume content of vinylene carbonate in the organic electrolyte was 0.67 volume%.
[0100]
For the batteries of Examples 1 to 13 and Comparative Examples 1 to 5 produced as described above, when the charge / discharge current is indicated by C, a current limiting circuit of 1 C is provided for the R5 type with 650 mA as 1 C and 4.2 V. , And then discharged to 3.0V. The battery was disassembled in a glove box under an argon atmosphere, and the positive electrode and the negative electrode taken out were immersed and washed in methyl ethyl ketone for 15 hours, dried in vacuum for 5 hours, and then subjected to fluorescent X-ray C, O, Na, Mg, Al, Si, When the total content of S, Ca, Fe, Ni, Cu and Zr was 100% by mass, the content x (% by mass) and y (% by mass) of the S element were measured. Tables 1 and 2 show the calculation results of (x / y = S content of negative electrode / S content of positive electrode) at that time. Further, the batteries of Examples 1 to 13 and Comparative Examples 1 to 5 were provided with current limiting circuits of 0.1 C, 0.3 C, 0.4 C, 0.5 C, and 0.6 C with 650 mA as 1 C. Initial charging was performed at a constant voltage of 4.2V. The battery was disassembled in a glove box in an argon atmosphere, and the reaction unevenness on the negative electrode surface was observed. Tables 1 and 2 show the results.
[0101]
Further, the batteries of Examples 1 to 13 and Comparative Examples 1 to 5 were provided with a current limiting circuit of 0.5 C and initially charged at a constant voltage of 4.2 V, and then the voltage between the electrodes of the batteries was reduced to 3.0 V. Discharge was carried out until it decreased. The battery was recharged at a constant voltage of 4.2 V with a 1 C current limiting circuit, and the battery was repeatedly charged and discharged until the inter-electrode voltage of the battery dropped to 3.0 V.
[0102]
Then, in the repetition of charging and discharging of the battery at this time, 2C was discharged at the 100th cycle, and 1C was discharged again at the 101st cycle. The load characteristic (%) was obtained by multiplying 100 by the value obtained by dividing the 2C discharge capacity at the 100th cycle by the 1C discharge capacity at the 101st cycle. The results are shown in Tables 1 and 2 as load characteristics [2C / 1C (%)].
[0103]
[Table 1]

[0104]
[Table 2]

[0105]
As is clear from the comparison between the battery characteristics of the batteries of Examples 1 to 13 shown in Table 1 and the battery characteristics of the batteries of Comparative Examples 1 to 5 shown in Table 2, the batteries of Examples 1 to 13 Compared to the batteries of Nos. To 5, even if the initial charge current value is increased, the reaction unevenness is less likely to occur, so that the current value can be increased, and as a result, the initial charge time can be shortened. Further, the batteries of Examples 1 to 13 also had excellent load characteristics.
[0106]
Example 14
A negative electrode was prepared as follows.
First, the specific surface area of the negative electrode active material was 3.0 m. ² / G of graphite, 96 parts by mass of graphite, 1 part by mass of lithium benzenesulfonate as an S-containing compound, 1 part by mass of lithium phosphate as a P-containing compound, 1 part by mass of styrene-butadiene rubber and 1 part by mass of carboxymethyl cellulose as a binder A part thereof was dissolved in water, and all of the above were mixed to prepare a coating for forming a negative electrode coating film.
[0107]
The obtained paint was applied on a conductive substrate made of a copper foil having a thickness of 10 μm using an applicator, and dried at 100 ° C. to form a coating film. The paint was also applied to the back side of the conductive substrate made of the copper foil and dried to prepare an electrode body. Thereafter, the electrode body was vacuum-dried at 100 ° C. for 10 hours and roll-pressed to obtain a sheet-shaped negative electrode. The coating density of this negative electrode is 1.5 g / cm ³ Met. The water content of the negative electrode measured by the Karl Fischer method was 118 ppm. The amount of water in the negative electrode was measured by cutting the negative electrode into a test piece of 2 cm × 5 cm, heating the sample to 170 ° C., and introducing steam that came out into a Karl Fischer device. The above water content was expressed as the mass of water in the negative electrode with respect to the mass of the coating film.
[0108]
A positive electrode was prepared as follows.
95 parts by mass of lithium cobalt oxide, 1 part by mass of carbon black as an electron conduction aid, 1 part by mass of flake graphite, and 3 parts by mass of polyvinylidene fluoride as a binder were N-methyl-2-pyrrolidone. Was used to prepare a coating for forming a positive electrode coating system. The preparation of the paint was performed as follows. First, a binder solution was prepared by dissolving polyvinylidene fluoride in N-methyl-2-pyrrolidone. Next, lithium cobalt oxide as a positive electrode active material, carbon black and flaky graphite as electron conduction aids were added to the binder solution, and mixed to prepare a coating material.
[0109]
And the obtained paint was apply | coated using the applicator on the conductive base which consists of a 15-micrometer-thick aluminum foil, and it dried at 100-120 degreeC, and formed the coating film. Similarly, the paint was applied and dried on the back side of the aluminum foil to form an electrode body. The electrode body was vacuum-dried at 100 ° C. for 10 hours and roll-pressed to obtain a sheet-shaped positive electrode. The coating density of this electrode is 3.30 g / cm. ³ Met.
[0110]
1.2 mol / l LiPF as electrolyte ₆ Was dissolved in a mixed solvent having a volume ratio of ethylene carbonate and methyl ethyl carbonate of 1: 2.
[0111]
The assembly of the cylindrical organic electrolyte battery was performed as follows.
First, the sheet-shaped positive electrode was cut into a band shape having a width of 28 mm × length 220 mm, and the sheet-shaped negative electrode was cut into a band shape having a width of 30 mm × length 260 mm. Then, a part of the coating film at the end of each electrode was peeled off, and an aluminum lead body was resistance-welded to a portion where the metal foil was exposed, from a microporous polypropylene film having a thickness of 20 μm and a porosity of 50%. A strip separator is interposed between the sheet-shaped positive electrode and the sheet-shaped negative electrode, spirally wound to produce a spiral electrode body, and the spiral electrode body is inserted into the same battery case as in Example 1. did. Then, the leading end of the lead body on the negative electrode side is welded to the bottom in the battery case by penetrating the insulator, and further, the insulator is inserted into the opening of the battery case to form a groove. Was welded. Then, after the can body manufactured through such a process is vacuum-dried at 60 ° C. for 10 hours, 2 ml of an electrolytic solution is injected in a dry atmosphere, and the container is sealed. A type organic electrolyte battery (outer diameter: 14.95 mm, height: 39.7 mm) was produced.
[0112]
Example 15
3.0 m specific surface area as negative electrode active material ² / G of graphite, 97 parts by mass of lithium benzenesulfonate as an S-containing compound, 0.5 parts by mass of lithium phosphate as a P-containing compound, and 1 part by mass of styrene-butadiene rubber as a binder. A negative electrode was produced in the same manner as in Example 14, except that 1 part by mass of carboxymethyl cellulose was dissolved in water. The water content of the negative electrode was 125 ppm. A cylindrical organic electrolyte battery was manufactured in the same manner as in Example 14, except that the negative electrode was used.
[0113]
Example 16
3.0 m specific surface area as negative electrode active material ² / G of graphite, 92 parts by mass of lithium, 3 parts by mass of lithium benzenesulfonate as an S-containing compound, 3 parts by mass of lithium phosphate as a P-containing compound, 1 part by mass of styrene-butadiene rubber and 1 part by mass of carboxymethyl cellulose as binders. A negative electrode was produced in the same manner as in Example 1 except that a part thereof was dissolved in water. The water content of the negative electrode was 107 ppm. A cylindrical organic electrolyte battery was manufactured in the same manner as in Example 14, except that the negative electrode was used.
[0114]
Example 17
1.2 mol / l LiPF as electrolyte ₆ Prepared by adding γ-butyrolactone at a volume content of 3% by volume to a mixed solvent having a volume ratio of ethylene carbonate and methyl ethyl carbonate of 1: 2. Was manufactured.
[0115]
The specific surface area of the negative electrode active material was 3.0 m. ² / G, the specific surface area of the negative electrode active material is 1.0 m ² / G of γ-butyrolactone in the organic electrolyte was 1.0% by volume. The water content of the negative electrode of this battery was 125 ppm.
[0116]
Example 18
1.2 mol / l LiPF as electrolyte ₆ Was prepared by adding γ-butyrolactone at a volume content of 2% by volume to a mixed solvent having a volume ratio of ethylene carbonate and methyl ethyl carbonate of 1: 2. Was manufactured.
[0117]
The specific surface area of the negative electrode active material was 3.0 m. ² / G, the specific surface area of the negative electrode active material is 1.0 m ² / G of γ-butyrolactone in the organic electrolyte was 0.67% by volume. The water content of the negative electrode of this battery was 125 ppm.
[0118]
Example 19
1.2 mol / l LiPF as electrolyte ₆ Was prepared by adding γ-butyrolactone at a volume content of 3% by volume and vinylene carbonate at a volume content of 2% by volume to a mixed solvent having a volume ratio of ethylene carbonate and methyl ethyl carbonate of 1: 2, Otherwise, a cylindrical organic electrolyte battery was manufactured in the same manner as in Example 15.
[0119]
The specific surface area of the negative electrode active material was 3.0 m. ² / G, the specific surface area of the negative electrode active material is 1.0 m ² / G of γ-butyrolactone in the organic electrolyte per volume was 1.0% by volume, and the specific surface area of the negative electrode active material was 1.0 m ² Per volume / g of vinylene carbonate in the organic electrolyte was 0.67% by volume. The water content of the negative electrode of this battery was 125 ppm.
[0120]
Example 20
A cylindrical organic electrolyte battery was manufactured in the same manner as in Example 15 except that the negative electrode was used at a moisture content of 75 ppm measured by the Karl Fischer method.
[0121]
Example 21
1.2 mol / l LiPF as electrolyte ₆ Prepared by adding γ-butyrolactone at a volume content of 7% by volume to a mixed solvent having a volume ratio of ethylene carbonate and methyl ethyl carbonate of 1: 2. Was manufactured.
[0122]
The specific surface area of the negative electrode active material was 3.0 m. ² / G, the specific surface area of the negative electrode active material is 1.0 m ² The volume content of γ-butyrolactone in the organic electrolyte per g / g was 2.3% by volume. The water content of the negative electrode of this battery was 125 ppm.
[0123]
Example 22
1.2 mol / l LiPF as electrolyte ₆ Prepared by adding vinylene carbonate at a volume content of 4% by volume to a mixed solvent having a volume ratio of ethylene carbonate and methyl ethyl carbonate of 1: 2. An electrolyte battery was manufactured.
[0124]
The specific surface area of the negative electrode active material was 3.0 m. ² / G, the specific surface area of the negative electrode active material is 1.0 m ² Per volume / g of vinylene carbonate in the organic electrolyte was 1.3% by volume. The water content of the negative electrode of this battery was 125 ppm.
[0125]
Comparative Example 6
3.0 m specific surface area as negative electrode active material ² / G of graphite and 98 parts by mass of styrene-butadiene rubber and 1 part by mass of carboxymethylcellulose in water without using lithium benzenesulfonate as an S-containing compound or lithium phosphate as a P-containing compound. A negative electrode was produced in the same manner as in Example 14 except that the dissolved one was used, and a cylindrical organic electrolyte battery was produced in the same manner as in Example 14 except that the negative electrode was used. The water content of the negative electrode of this battery was 126 ppm.
[0126]
Comparative Example 7
3.0 m specific surface area as negative electrode active material ² / G of graphite / 97 parts by mass, 1 part by mass of lithium phosphate as a P-containing compound, 1 part by mass of styrene-butadiene rubber and 1 part by mass of carboxymethyl cellulose as binders without using lithium benzenesulfonate as an S-containing compound A negative electrode was produced in the same manner as in Comparative Example 6 except that a part thereof was dissolved in water, and a cylindrical organic electrolyte battery was produced in the same manner as in Example 14 except that the negative electrode was used. The water content of the negative electrode of this battery was 112 ppm.
[0127]
Comparative Example 8
3.0 m specific surface area as negative electrode active material ² / G of graphite, 97.8 parts by mass of graphite, 0.1 part by mass of lithium benzenesulfonate as an S-containing compound, 0.1 part by mass of lithium phosphate as a P-containing compound, and 1 part by mass of styrene-butadiene rubber as a binder. Part and 1 part by weight of carboxymethylcellulose were dissolved in water, and a negative electrode was produced in the same manner as in Comparative Example 6 except that the negative electrode was used. A battery was manufactured. The water content of the negative electrode of this battery was 128 ppm.
[0128]
When the charge and discharge currents of the batteries of Examples 14 to 22 and Comparative Examples 6 to 8 prepared as described above are indicated by C, a current limiting circuit of 1 C is provided for the R5 type with 650 mA as 1 C and 4.2 V. , And then discharged to 3.0V. The battery was disassembled in a glove box in an argon atmosphere, and the positive electrode and the negative electrode taken out were each immersed and washed in methyl ethyl carbonate for 15 hours, dried in vacuum for 5 hours, and then subjected to C, O, Na, Mg, Al, X-ray fluorescence analysis. When the total content of Si, S, Ca, Fe, Ni, Cu and Zr was 100% by mass, the contents x (% by mass) and y (% by mass) of the S element were measured. Table 3 shows the calculation results of (x / y = S content of negative electrode / S content of positive electrode) at that time.
[0129]
Further, the batteries of Examples 14 to 22 and Comparative Examples 6 to 8 having the same current as described above were subjected to current limiting of 0.1 C, 0.3 C, 0.4 C, 0.5 C, 0.6 C, and 0.7 C with 650 mA as 1 C. The circuit was provided and the first charge was performed at a constant voltage of 4.2V. The battery was disassembled in a glove box in an argon atmosphere, and the reaction unevenness on the negative electrode surface was observed. Table 4 shows the results.
[0130]
Further, the batteries of Examples 14 to 22 and Comparative Examples 6 to 8 were provided with a current limiting circuit of 0.5 C, initially charged at a constant voltage of 4.2 V, and then charged at a current value of 1 C between the electrodes of the batteries. The discharge was performed until the voltage dropped to 3.0V. The battery was charged again with a constant voltage of 4.2 V provided with a current limiting circuit of 1 C, and the battery was repeatedly charged / discharged so that the voltage between the electrodes dropped to 3.0 V.
[0131]
In the repetition of charging and discharging of the battery at this time, the battery was charged at 90% under the above-described conditions at the 10th cycle, then left at room temperature for 1 day, decomposed in an inert atmosphere, and the negative electrode was taken out. This was vacuum-dried for 24 hours without being exposed to outside air, and then subjected to X-ray photoelectron spectroscopy. The X-ray photoelectron spectroscopy analysis was carried out using “PHI5500MC” manufactured by ULVAC-PHI, Inc. at 400 W using Al-Kα radiation, split the peaks, and calculated the amount of atoms at each peak on the negative electrode surface. Table 3 shows the results.
[0132]
[Table 3]

[0133]
In addition, the batteries of Examples 14 to 22 and Comparative Examples 6 to 8 were provided with a current limiting circuit of 0.5 C and initially charged at a constant voltage of 4.2 V, and then the voltage between the electrodes of the batteries was reduced to 3.0 V. Discharged until The battery was recharged at a constant voltage of 4.2 V with a 1 C current limiting circuit, and the battery was repeatedly charged and discharged until the inter-electrode voltage of the battery dropped to 3.0 V.
[0134]
Then, in the repetition of charging and discharging of the battery at this time, 2C was discharged at the 100th cycle, and 1C was discharged again at the 101st cycle. The load characteristic (%) was obtained by multiplying 100 by the value obtained by dividing the 2C discharge capacity at the 100th cycle by the 1C discharge capacity at the 101st cycle. Table 4 shows the results as load characteristics [2C / 1C (%)].
[0135]
Further, for the batteries of Examples 14 to 22 and Comparative Examples 6 to 8, the test was stopped at the charge state of 4.2 V at the tenth cycle in the repetition of charge / discharge similar to the above, and thereafter, 12 V was set as the upper limit voltage. The battery was overcharged at 0.5 A, 1 A, 2 A, and 4 A, and an overcharge safe current value was measured. Table 4 shows the results. Note that the overcharge safe current value is that the battery was overcharged at 0.5 A, 1 A, 2 A, 3 A, and 4 A with a maximum voltage of 12 V after the battery was fully charged at 4.2 V, and the battery surface temperature was 135 ° C. or less. It is called the maximum current.
[0136]
[Table 4]

* ○: no reaction unevenness, Δ: slight reaction unevenness, ×: reaction unevenness
[0137]
As is evident from the results shown in Table 4, the batteries of Examples 14 to 22 have a larger current value than the batteries of Comparative Examples 6 to 8 even when the initial charging current value is larger, because reaction unevenness is less likely to occur. As a result, the initial charging time can be shortened. Further, the batteries of Examples 14 to 22 had excellent storage characteristics, high overcharge safety current, and excellent safety during overcharge.
[0138]
【The invention's effect】
As described above, according to the present invention, in any of the first to sixth aspects, it is possible to provide an organic electrolyte battery that can reduce the time required for initial charging and improve productivity. Can be.
[0139]
In the present invention, as in the sixth aspect, a peak of 286 to 287 eV based on carbon atoms derived from CO by X-ray photoelectron spectroscopy on the negative electrode surface in a state of 90% charge with respect to the standard capacity of the battery. And the amount of phosphorus atoms determined from the peak of 133 to 135 eV based on phosphorus derived from POx to 1 atomic% or more, as described above, In addition to shortening the time required for the first charge, it is possible to provide a high-capacity organic electrolyte battery with high safety at the time of overcharge.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically showing one example of an organic electrolyte battery of the present invention.
[Explanation of symbols]
1 positive electrode
2 Negative electrode
3 separator
4 Electrolyte
5 Battery case

Claims (6)

In an organic electrolyte battery including a negative electrode, a positive electrode, and an organic electrolyte, a lithium-containing material having a specific surface area of 1.0 m ² / g or more was used as a negative electrode active material, and C and O of the negative electrode were determined by fluorescent X-ray analysis. , Na, Mg, Al, Si, S, Ca, Fe, Ni, Cu and Zr, the content x (mass%) of the S element when the total content is 100 mass%, Content of S element y (% by mass) when the total content of C, O, Na, Mg, Al, Si, S, Ca, Fe, Ni, Cu and Zr by X-ray analysis is 100% by mass. An organic electrolyte battery characterized by being at least twice as large as the above. ^2. The organic electrolyte battery according to claim 1, wherein the negative electrode active material contains 0.05 to 3% by volume of γ-butyrolactone in a volume content of the organic electrolyte per 1.0 m ² / g of the specific surface area of the negative electrode active material. . ^2. The organic electrolyte battery according to claim 1, wherein vinylene carbonate is contained in an amount of 0.05 to 2% by volume in the organic electrolyte based on a specific surface area of 1.0 m ² / g of the negative electrode active material. The negative electrode active material contains 0.025 to 2% by volume of γ-butyrolactone per 1.0 m ² / g in terms of volume content in the organic electrolyte solution, and vinylene carbonate in the organic electrolyte solution. The organic electrolyte battery according to claim 1, wherein the content is 0.025 to 1% by volume. 2. The organic electrolyte battery according to claim 1, wherein the water content of the negative electrode is 100 ppm or less. The amount of carbon atoms determined from the peak of 286 to 287 eV based on carbon atoms derived from CO by X-ray photoelectron spectroscopy on the negative electrode surface in a charged state of 90% with respect to the standard capacity of the battery is 6.5 atomic%. 6. The organic electrolyte battery according to claim 1, wherein the amount of phosphorus atoms determined from a peak of 133 to 135 eV based on phosphorus derived from POx is 1 atomic% or more. 7. .

Images