JP4569074B2 - Method for manufacturing lithium secondary battery - Google Patents
Method for manufacturing lithium secondary battery Download PDFInfo
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- JP4569074B2 JP4569074B2 JP2003145858A JP2003145858A JP4569074B2 JP 4569074 B2 JP4569074 B2 JP 4569074B2 JP 2003145858 A JP2003145858 A JP 2003145858A JP 2003145858 A JP2003145858 A JP 2003145858A JP 4569074 B2 JP4569074 B2 JP 4569074B2
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- electrode sheet
- negative electrode
- positive electrode
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- lithium secondary
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- 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
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Description
【０００１】
【発明の属する技術分野】
本発明は、リチウム二次電池の製造方法に関する。
【０００２】
【従来の技術】
リチウム二次電池はエネルギー密度が高いので、パーソナルコンピュータ、携帯電話、携帯情報端末などを含む携帯用情報機器の電源として用いられている。このリチウム二次電池は、高いエネルギー密度を有しており、もし事故により内部短絡・外部短絡が生じて発熱したときの発熱量が大きいので、一定以上の発熱を防止することにより高い安全性を確保することが求められている。事故の場合に一定以上の発熱が防止できるものとして、正極シートと負極シートの間に配置され正極シートと負極シートが直接接触しないよう隔てるセパレータを配置した電極群を有してなるリチウム二次電池が一般的であり、セパレータは、発熱した場合に電流を遮断し、それ以上の発熱を防止するシャットダウン機能を有する。
【０００３】
このようなセパレータを有したリチウム二次電池に用いられている電極群は、正極集電体に正極用電極合剤が塗布されてなる正極シートと、負極集電体に負極用電極合剤が塗布されてなる負極シートと、セパレータとを巻回して製造されている。ここで、正極シートと負極シートとセパレータには張力がかかった状態で巻回されていくが、従来においては、最外周部は正極シートと負極シートとセパレータとが切断された後には、張力がかからない状態で巻回されていた（例えば、特許文献１参照。）。このような電極群を有してなるリチウム二次電池の製造方法において、従来よりも安全性が高いリチウム二次電池が得られる製造方法が求められていた。
【０００４】
【特許文献１】
特開平７−１７２６４４号公報
【０００５】
【発明が解決しようとする課題】
本発明の目的は、従来よりも安全性が高いリチウム二次電池が得られるリチウム二次電池の製造方法を提供することにある。
【０００６】
【課題を解決するための手段】
本発明者らは、上記課題を解決するために、リチウム二次電池の製造方法について鋭意検討した結果、正極集電体に正極用電極合剤が塗布されてなる正極シートと、負極集電体に負極用電極合剤が塗布されてなる負極シートと、セパレータとを含む電極部材を巻回して製造される電極群を有してなるリチウム二次電池の製造方法において、正極シートまたは負極シートのうち最外周側のいずれかのシートの電極合剤が塗布された部分の終端が巻回されるまで、該正極シートおよび該負極シートのうちの一つ以上を一定の張力で巻回することにより、リチウム二次電池の安全性が向上することを見出し、本発明を完成させるに到った。
【０００７】
すなわち本発明は、正極集電体に正極用電極合剤が塗布されてなる正極シートと、負極集電体に負極用電極合剤が塗布されてなる負極シートと、セパレータとを含む電極部材を巻回して製造される電極群を有してなるリチウム二次電池の製造方法において、正極シートまたは負極シートのうち最外周側のいずれかのシートの電極合剤が塗布された部分の終端が巻回されるまで、該正極シートおよび該負極シートのうちの一つ以上を一定の張力で巻回することを特徴とするリチウム二次電池の製造方法を提供する。また本発明は、前記記載の製造方法により製造されたリチウム二次電池を提供する。
【０００８】
【発明の実施の形態】
本発明の製造方法においては、正極集電体に正極用電極合剤が塗布されてなる正極シートと、負極集電体に負極用電極合剤が塗布されてなる負極シートとセパレータとを含む電極部材を巻回して製造される電極群を有してなるリチウム二次電池の製造方法において、正極シートまたは負極シートのうち最外周側のいずれかのシートの電極合剤が塗布された部分の終端が巻回されるまで、該正極シートおよび該負極シートのうちの一つ以上を一定の張力で巻回する。
【０００９】
ここで、一定の張力とは、正極シートおよび負極シートの各々にかかる張力が、相互には別の値であっても、各々の張力について、巻回の開始から、正極シートまたは負極シートのうち最外周側のいずれかのシートの電極合剤が塗布された部分の終端が巻回されるまで、実質的に同一であることであり、巻回中の張力の値の変動は、２０％以内が好ましく、１０％以内がさらに好ましい。また、正極シートおよび負極シートにかかる張力を、６０ｇ／ｃｍ以下とすることがリチウム二次電池の安全性を向上させるために好ましい。セパレータにかかる張力は４０ｇ／ｃｍ以下が好ましい。正極シート、負極シートにかかる張力はそれぞれ０ｇ／ｃｍとすることもできる。そして、正極シートと負極シートにかかる張力は、実質的に同一とすることが好ましい。
【００１０】
次に、本発明の製造方法において用いることができる巻回方法について説明する。
巻回方法は、正極シートおよび負極シートのうちの一つ以上にかかる張力を一定に制御できるものであれば、特に限定されず、通常用いられている巻回装置を用いることができる。正極シートおよび負極シートにかかる張力がいずれも不均一な条件で巻回された場合、リチウム二次電池の安全性が低下する。これは、充電および放電時に正極シート、負極シートが伸縮し、それらの間に発生する摩擦力により、セパレータが損傷することによるものと思われる。本発明のリチウム二次電池の製造方法としては、最外周側となる正極シートまたは負極シートの集電体の電極合剤を塗布していない部分が長くなるように電極合剤を集電体に塗布し、巻回の始めから、電極合剤が塗布された部分の終端が巻回されるまで、一定の張力をかけた状態で巻回した後、不要な集電体を切断し、さらに最外周にセパレータを巻回し、セパレータを切断した後に、セパレータの端部を粘着テープで止める方法が具体的に挙げられる。正極シートまたは負極シートにかかる張力を０ｇ／ｃｍとして巻回を行うには、セパレータ上に正極シートまたは負極シートを載せ、セパレータのみに張力をかけて巻き込むことにより行うことができる。
【００１１】
最外周側でない方の負極シートまたは正極シートの集電体の電極合剤を塗布していない部分が長くなるように電極合剤を集電体に塗布し、巻回の始めから、電極合剤が塗布された部分の終端が巻回されるまで、一定の張力をかけた状態で巻回しても良いが、この場合には、一周余分に巻回しなくてはならず、電池容量が低下するので好ましくない。
【００１２】
本発明のリチウム二次電池の製造方法およびリチウム二次電池において、電極群巻回時にセパレータを２本用い、正極シート側と負極シート側に配して巻回することもできるし、１本のセパレータを用いて、長い帯状のセパレータの中央部から片端にかけて正極シートを重ねて配置し、セパレータの中央部からもう一方の片端にかけて正極シートが設置された側とはセパレータの反対側に負極シートを重ねて配置し、セパレータの中央部で折ってセパレータの中央部から巻回することもできる。２本のセパレータを用いる場合には、各々のセパレータの張力を、１本のセパレータを用いる場合には両端の張力を異なる値として巻回することもできるが、２つの張力が実質的に同じである方が好ましい。
【００１３】
本発明における電極群の外観の形状は、必ずしも円筒形である必要はなく、巻回の軸と垂直方向に切断した断面が楕円や長方形とすることもできる。本発明のリチウム二次電池の形状は、特に限定されるものではなく、ペーパー型、コイン型、円筒型、角形などのいずれであってもよい。
【００１４】
次に、本発明の製造方法により製造されるリチウム二次電池について説明する。
本発明の製造方法において用いる正極シートは、通常、正極活物質、導電材および結着剤を含む電極合剤を集電体上に担持したものを用いる。正極活物質としては、リチウムイオンをドープ・脱ドープ可能な材料を含み、導電材として炭素質材料を含み、結着剤として熱可塑性樹脂などを含むものが好ましく、具体的にはＶ、Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉなどの遷移金属を少なくとも１種含むリチウム複合酸化物が挙げられる。中でも好ましくは、平均放電電位が高いという点で、コバルト酸リチウム、ニッケル酸リチウム、ニッケル酸リチウムのニッケルの一部を他元素と置換したもの、などのα−ＮａＦｅＯ2型構造を母体とする層状リチウム複合酸化物、リチウムマンガンスピネルなどのスピネル型構造を母体とするリチウム複合酸化物などが挙げられる。
【００１５】
前記正極シートの製造に用いる結着剤としては熱可塑性樹脂が用いられ、具体的には、ポリビニリデンフロライド、ビニリデンフロライドの共重合体、ポリテトラフルオロエチレン、テトラフルオロエチレン−ヘキサフロロプロピレンの共重合体、テトラフルオロエチレン−パーフルオロアルキルビニルエーテルの共重合体、エチレン−テトラフルオロエチレンの共重合体、ビニリデンフロライド−ヘキサフルオロプロピレン−テトラフルオロエチレンの共重合体、熱可塑性ポリイミド、カルボキシメチルセルロース、ポリエチレン、ポリプロピレンなどが挙げられる。
【００１６】
前記正極シートの製造に用いる導電剤としては炭素質材料が用いられ、具体的には天然黒鉛、人造黒鉛、コークス類、カーボンブラックなどが挙げられる。導電材として、それぞれ単独で用いてもよいし、例えば人造黒鉛とカーボンブラックとを混合して用いてもよい。
【００１７】
前記正極シートの製造に用いる集電体としては、Ａｌ、ステンレスなどを用いることができるが、軽量であり、安価であり、かつ薄膜に加工しやすいという点でＡｌが好ましい。集電体に正極活物質を含む正極用電極合剤を塗布する方法としては、加圧成型する方法、または溶媒などを用いてペースト化し集電体上に塗布乾燥後プレスするなどして圧着する方法が挙げられる。
【００１８】
本発明の製造方法において用いる負極シートは、リチウムイオンをドープ・脱ドーブ可能な材料を結着剤を含む電極合剤として集電体上に担持したもの、またはリチウム金属、リチウム合金などを用いることができ、リチウムイオンをドープ・脱ドーブ可能な材料としては、具体的には、天然黒鉛、人造黒鉛、コークス類、カーボンブラック、熱分解炭素類、炭素繊維、有機高分子化合物焼成体などの炭素質材料が挙げられ、正極よりも低い電位でリチウムイオンのドープ・脱ドープを行う酸化物、硫化物等のカルコゲン化合物を用いることもできる。炭素質材料として、電位平坦性が高く、また平均放電電位が低いため正極と組み合わせた場合大きなエネルギー密度が得られるという点で、天然黒鉛、人造黒鉛等の黒鉛材料を主成分とする炭素質材料が好ましい。
【００１９】
また、液体の電解質と組み合わせて用いる場合において、液体の電解質がエチレンカーボネートを含有しないときには、ポリエチレンカーボネートを含有した負極用電極合剤を用いると、サイクル特性と大電流放電特性が向上するので好ましい。炭素質材料の形状は、例えば天然黒鉛のような薄片状、メソカーボンマイクロビーズのような球状、黒鉛化炭素繊維のような繊維状、または微粉末の凝集体などのいずれでもよく、必要に応じて結着剤としての熱可塑性樹脂を添加することができる。熱可塑性樹脂としては、ポリビニリデンフロライド、ポリビニリデンフロライドの共重合体、ビニリデンフロライド−ヘキサフロロプロピレン−テロラフロロエチレンの共重合体、熱可塑性ポリイミド、カルボキシメチルセルロース、ポリエチレン、ポリプロピレンなどが挙げられる。負極として用いられる酸化物、硫化物等のカルコゲン化合物としては、例えばスズ酸化物を主体とした非晶質化合物のような、周期率表の１３、１４、１５族を主体とした結晶質または非晶質の酸化物などが挙げられる。これらについても、必要に応じて導電材としての炭素質材料、結着剤としての熱可塑性樹脂を添加することができる。
【００２０】
前記負極シートに用いる負極集電体としては、Ｃｕ、Ｎｉ、ステンレスなどを用いることができるが、リチウムと合金を作り難く、かつ薄膜に加工しやすいという点でＣｕが好ましい。該負極集電体に負極用電極合剤を担持させる方法は正極と同様であり、加圧成型する方法、または溶媒などを用いてペースト化し集電体上に塗布乾燥後プレスするなどして圧着する方法が挙げられる。
【００２１】
本発明の製造方法において、セパレータは、シャットダウン機能を有するものを用いる。さらに、セパレータは、シャットダウン機能を有する層と、耐熱樹脂からなる耐熱多孔質層とを有することが、電池の安全性を向上するために望ましい。
【００２２】
シャットダウン機能を有する層は、シャットダウン機能を有するものであれば、特に限定されないが、通常、熱可塑性樹脂からなる多孔質層である。シャットダウン層は、８０℃〜１８０℃の温度で実質的に無孔性の層となるものであることが好ましいので、シャットダウン層を形成する熱可塑性樹脂としては、８０〜１８０℃で軟化し多孔質の空隙が閉塞され、かつ電解液に溶解しない熱可塑性樹脂が好ましい。具体的には、ポリオレフィン、熱可塑性ポリウレタンなどが挙げられる。ポリオレフィンとしては、低密度ポリエチレン、高密度ポリエチレン、超高分子量ポリエチレンなどのポリエチレン、ポリプロピレンなどから選ばれた少なくとも１種の熱可塑性樹脂がより好ましい。
【００２３】
シャットダウン層の空隙の大きさ、または該空隙が球形に近似できるときはその球の直径（以下、孔径ということがある）は、３μｍ以下が好ましく、１μｍ以下がさらに好ましい。シャットダウン層の空隙率は、３０〜８０体積％が好ましく、さらに好ましくは４０〜７０体積％であり、厚みは３〜３０μｍが好ましく、さらに好ましくは５〜２０μｍである。
【００２４】
前記耐熱多孔質層は、耐熱性樹脂からなることが好ましい。本発明における耐熱多孔質層を形成する耐熱樹脂としては、ＪＩＳ Ｋ ７２０７に準拠して測定した１８．６ｋｇ／ｃｍ2の荷重時における荷重たわみ温度が１００℃以上の樹脂から選ばれた少なくとも１種の耐熱樹脂が好ましい。
【００２５】
該荷重たわみ温度が１００℃以上の樹脂としては、具体的にはポリイミド、ポリアミドイミド、アラミド、ポリカーボネート、ポリアセタール、ポリサルホン、ポリフェニルサルファイド、ポリエーテルエーテルケトン、芳香族ポリエステル、ポリエーテルサルホン、ポリエーテルイミドなどが挙げられる。
【００２６】
前記耐熱多孔質層の空隙の大きさ、または孔径は、３μｍ以下が好ましく、１μｍ以下がさらに好ましい。また、耐熱多孔質層の空孔率は、３０〜８０体積％が好ましく、さらに好ましくは４０〜７０体積％である。厚みは１〜２０μｍが好ましく、さらに好ましくは２〜１０μｍである。
【００２７】
本発明のリチウム二次電池に用いる非水電解質溶液としては、例えばリチウム塩を有機溶媒に溶解させた非水電解質溶液を用いることができる。リチウム塩としては、ＬｉＣｌＯ4、ＬｉＰＦ6、ＬｉＡｓＦ6、ＬｉＳｂＦ6、ＬｉＢＦ4、ＬｉＣＦ3ＳＯ3、ＬｉＮ（ＳＯ2ＣＦ3）2、ＬｉＣ（ＳＯ2ＣＦ3）3、Ｌｉ2Ｂ10Ｃｌ10、低級脂肪族カルボン酸リチウム塩、ＬｉＡｌＣｌ4などのうち１種または２種以上の混合物が挙げられる。リチウム塩として、これらの中でもフッ素を含むＬｉＰＦ6、ＬｉＡｓＦ6、ＬｉＳｂＦ6、ＬｉＢＦ4、ＬｉＣＦ3ＳＯ3、ＬｉＮ（ＣＦ3ＳＯ2）2、およびＬｉＣ（ＣＦ3ＳＯ2）3からなる群から選ばれた少なくとも１種を含むものを用いることが好ましい。
【００２８】
前記非水電解液に用いる有機溶媒としては、例えばプロピレンカーボネート、エチレンカーボネート、ビニレンカーボネート、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、４−トリフルオロメチル−１，３−ジオキソラン−２−オン、１，２−ジ（メトキシカルボニルオキシ）エタンなどのカーボネート類；１，２−ジメトキシエタン、１，３−ジメトキシプロパン、ペンタフルオロプロピルメチルエーテル、２，２，３，３−テトラフルオロプロピルジフルオロメチルエーテル、テトラヒドロフラン、２−メチルテトラヒドロフランなどのエーテル類；ギ酸メチル、酢酸メチル、γ−ブチロラクトンなどのエステル類；アセトニトリル、ブチロニトリルなどのニトリル類；Ｎ，Ｎ−ジメチルホルムアミド、Ｎ，Ｎ−ジメチルアセトアミドなどのアミド類；３−メチル−２−オキサゾリドンなどのカーバメート類；スルホラン、ジメチルスルホキシド、１，３−プロパンサルトンなどの含硫黄化合物、または上記の有機溶媒にフッ素置換基を導入したものを挙げることができ、通常はこれらのうちの２種以上を混合して用いる。
【００２９】
これらの中でもカーボネート類を含む混合溶媒が好ましく、環状カーボネートと非環状カーボネート、または環状カーボネートとエーテル類の混合溶媒がさらに好ましい。環状カーボネートと非環状カーボネートの混合溶媒としては、動作温度範囲が広く、負荷特性に優れ、かつ負極の活物質として天然黒鉛、人造黒鉛等の黒鉛材料を用いた場合でも難分解性であるという点で、エチレンカーボネート、ジメチルカーボネートおよびエチルメチルカーボネートを含む混合溶媒が好ましい。
【００３０】
【実施例】
以下、本発明を実施例によりさらに詳細に説明するが、本発明はこれらによって何ら限定されるものではない。
【００３１】
実施例１
（１）正極シートの作製
カルボキシメチルセルロース１重量部を水に溶解し、ポリテトラフルオロエチレンが４．５重量部となるようにポリテトラフルオロエチレンの６０重量％水分散液と、アセチレンブラック２．５重量部と正極活物質であるコバルト酸リチウム粉末９２重量部を分散混練し正極用電極合剤のペーストとした。該ペーストを正極集電体である厚さ２０μｍのＡｌ箔の両面の所定部分に塗布し、乾燥、ロールプレス、スリットを行い正極シートを得た。正極用電極合剤の未塗布部分は２ｃｍであり、その端部にアルミリードを抵抗溶接した。
【００３２】
（２）負極シートの作製
カルボキシメチルセルロース２重量部を水に溶解し、天然黒鉛９８重量部を分散混練し負極用電極合剤のペーストとした。該ペーストを負極集電体である厚さ１２μｍのＣｕ箔の両面の所定部分に塗布し、乾燥、ロールプレス、スリットを行って負極シートを得た。負極用電極合剤の未塗布部分は、２ｃｍのものと３０ｃｍのものを作製し、その負極用電極合剤塗布側の端部にニッケルリードを抵抗溶接した。
【００３３】
（３）耐熱多孔質層を付与したセパレータの作製
３−ａ パラアラミド溶液の合成
撹拌翼、温度計、窒素流入管及び粉体添加口を有する５リットル（ｌ）のセパラブルフラスコを使用してポリ（パラフェニレンテレフタルアミド）（以下、ＰＰＴＡと略す）の合成を行った。フラスコを十分乾燥し，４２００ｇのＮＭＰを仕込み、２００℃で２時間乾燥した塩化カルシウム２７２．６５ｇを添加して１００℃に昇温した。塩化カルシウムが完全に溶解した後室温に戻して、パラフェニレンジアミン（以下、ＰＰＤと略す）１３２．９１ｇを添加し完全に溶解させた。この溶液を２０±２℃に保ったまま、テレフタル酸ジクロライド（以下、ＴＰＣと略す）２４３．３２ｇを１０分割して約５分おきに添加した。その後溶液を２０±２℃に保ったまま１時間熟成し、気泡を抜くため減圧下３０分撹拌した。得られた重合液は光学的異方性を示した。一部をサンプリングして水で再沈してポリマーとして取り出し、得られたＰＰＴＡの固有粘度を測定したところ１．９７ｄｌ／ｇであった。
次に、この重合液１００ｇを、攪拌翼、温度計、窒素流入管および液体添加口を有する５００ｍｌのセパラブルフラスコに秤取し、ＮＭＰ溶液を徐々に添加した。最終的に、ＰＰＴＡ濃度が２．０重量％のＰＰＴＡ溶液を調製し、これをＰ液とした。
【００３４】
（２）パラアラミド溶液の塗布とセパレータの作製
シャットダウン層としては、ＰＥ（ポリエチレン）製多孔質膜（膜厚１６μｍ、透気度４００秒／１００ｃｃ、平均細孔半径（水銀圧入法）０．０４μｍ）を用いた。テスター産業株式会社製バーコーター（間隙２００μｍ）により、ガラス板上に置いた上記ＰＥ製多孔質膜の上に耐熱樹脂溶液であるＰ液を塗布して、実験室内のドラフト内に約２０分間保持したところ、ＰＰＴＡが析出し、ＰＥ製多孔質膜上に白濁した膜状物が得られた。該膜状物が付着したＰＥ製多孔質膜をイオン交換水に浸漬し、５分後に膜状物をガラス板から剥離し、イオン交換水を流しながら充分に水洗した後、遊離水を拭き取った。この膜状物をナイロン布に挟み、さらにアラミド製フェルトに挟んだ。膜状物が付着したＰＥ製多孔質膜をナイロン布とアラミド製フェルトに挟んだ状態で、アルミ板を乗せ、その上にナイロンフィルムを被せ、ナイロンフィルムとアルミ板とをガムでシールして、減圧のための導管をつけた。全体を熱オーブンに入れ６０℃で減圧しながら膜状物を乾燥してＰＥ製多孔質膜からなるシャットダウン層とアラミド製多孔質膜（厚み：５μｍ）からなる耐熱多孔質層が積層された複合フィルム（厚み２１μｍ）を得てこれをセパレータとした。
【００３５】
（４）円筒電池の作製
上記のようにして作製した正極シート、負極シート（負極用電極合剤未塗布部３０ｃｍ）とセパレータとを、正極シート、セパレータ、負極シートの順になるように、また負極の合剤未塗布部が最外周になるように積層し、一端より巻き取って電極群とした。この際、最外周となる負極シートは、負極用電極合剤塗布部が完全に巻き取られ、さらに負極リードがセパレータに巻き取られるまで張力をかけた後、セパレータとともにカットした。その後、最外周部分に緩みがない様に巻き取った後、最外周のセパレータをテープで固定した。なおこのときの正極シートおよび負極シートへの張力は６０ｇ／ｃｍ、セパレータへの張力は３３ｇ／ｃｍとした。
前記の電極素子を電池缶に挿入し、非水電解質溶液としてエチレンカーボネートとジメチルカーボネートとエチルメチルカーボネートの体積比１６：１０：７４混合液にＬｉＰＦ6を１モル／リットルとなるように溶解したものを含浸し、正極端子を兼ねる電池蓋をガスケットを介してかしめて、１８６５０サイズの円筒型電池を得た。
【００３６】
また、このようにして得た円筒型電池２個について、４．４５Ｖの過充電状態で釘刺し試験を実施した。その結果、試験した電池には、過充電という苛酷な状態にもかかわらず、緩やかな温度上昇しか認められなかった。
【００３７】
実施例２
負極シートの負極用電極合剤の未塗布部が２ｃｍのものを用い、正極シートおよび負極シートへの張力を与えないこと以外は、実施例１と同様にして巻回し、電池内の電極合剤部の張力は一定（０ｇ／ｃｍ）として１８６５０サイズの円筒型電池を得た。この円筒型電池について、４．５Ｖの過充電状態で釘刺し試験を実施した。その結果、試験に供した電池は、４．５Ｖ過充電という実施例１よりさらに苛酷な状態にもかかわらず、実施例１と同様に緩やかな温度上昇しか認められなかった。
【００３８】
比較例１
負極シートの負極用電極合剤の未塗布部が２ｃｍのものを用い、最外周一周分を残すまでは、実施例１と同様にして巻回し、最外周一周分は張力を与えずに巻回することで、内周部と最外周部の張力が異なる１８６５０サイズの円筒型電池を得た。この円筒型電池について実施例１と同様に釘刺し試験を行なった結果、著しい温度上昇が認められた。
【００３９】
【発明の効果】
本発明により、従来より安全性が高いリチウム二次電池を製造することができるので、本発明は工業的に極めて有用である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a lithium secondary battery.
[0002]
[Prior art]
Lithium secondary batteries have high energy density, and are used as power sources for portable information devices including personal computers, cellular phones, and portable information terminals. This lithium secondary battery has a high energy density, and since the amount of heat generated when an internal short circuit or external short circuit occurs due to an accident and generates heat is high, it prevents high heat generation beyond a certain level, thereby increasing safety. It is required to ensure. A lithium secondary battery comprising an electrode group in which a separator is disposed between a positive electrode sheet and a negative electrode sheet so as to prevent direct contact between the positive electrode sheet and the negative electrode sheet, in order to prevent heat generation beyond a certain level in the event of an accident In general, the separator has a shutdown function that interrupts current when heat is generated and prevents further heat generation.
[0003]
The electrode group used in the lithium secondary battery having such a separator includes a positive electrode sheet in which a positive electrode current mixture is applied to a positive electrode current collector, and a negative electrode current collector in which a negative electrode electrode material mixture is applied. It is manufactured by winding a coated negative electrode sheet and a separator. Here, the positive electrode sheet, the negative electrode sheet, and the separator are wound in a tensioned state, but conventionally, the outermost peripheral portion has a tension after the positive electrode sheet, the negative electrode sheet, and the separator are cut. It was wound in a state that does not apply (see, for example, Patent Document 1). In the manufacturing method of a lithium secondary battery having such an electrode group, a manufacturing method capable of obtaining a lithium secondary battery with higher safety than before has been demanded.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 7-172644
[Problems to be solved by the invention]
The objective of this invention is providing the manufacturing method of the lithium secondary battery from which the lithium secondary battery whose safety | security is higher than before is obtained.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present inventors have intensively studied a method for producing a lithium secondary battery. As a result, a positive electrode sheet obtained by applying a positive electrode mixture to a positive electrode current collector, and a negative electrode current collector In a method for producing a lithium secondary battery comprising an electrode group produced by winding an electrode member comprising a negative electrode sheet coated with an electrode mixture for negative electrode and a separator, the positive electrode sheet or the negative electrode sheet By winding one or more of the positive electrode sheet and the negative electrode sheet with a constant tension until the end of the portion of the outermost sheet on which the electrode mixture is applied is wound. The present inventors have found that the safety of lithium secondary batteries is improved and have completed the present invention.
[0007]
That is, the present invention provides an electrode member comprising a positive electrode sheet in which a positive electrode mixture is applied to a positive electrode current collector, a negative electrode sheet in which a negative electrode electrode material is applied to a negative electrode current collector, and a separator. In the method of manufacturing a lithium secondary battery having an electrode group manufactured by winding, the end of the portion of the positive electrode sheet or the negative electrode sheet on which the electrode mixture of the outermost peripheral side is applied is wound. One embodiment of the present invention provides a method for producing a lithium secondary battery, in which one or more of the positive electrode sheet and the negative electrode sheet are wound with a constant tension until being rotated. The present invention also provides a lithium secondary battery manufactured by the manufacturing method described above.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
In the production method of the present invention, an electrode comprising a positive electrode sheet in which a positive electrode mixture is applied to a positive electrode current collector, a negative electrode sheet in which a negative electrode electrode mixture is applied to a negative electrode current collector, and a separator In the method for manufacturing a lithium secondary battery having an electrode group manufactured by winding a member, the terminal end of the positive electrode sheet or the negative electrode sheet on which the electrode mixture of any one of the outermost peripheral sheets is applied One or more of the positive electrode sheet and the negative electrode sheet are wound with a constant tension until is wound.
[0009]
Here, the constant tension means that even if the tension applied to each of the positive electrode sheet and the negative electrode sheet is different from each other, for each tension, from the start of winding, the positive electrode sheet or the negative electrode sheet It is substantially the same until the end of the portion of the outermost sheet on which the electrode mixture is applied is wound, and the variation in the tension value during winding is within 20%. Is preferable, and within 10% is more preferable. Moreover, it is preferable that the tension | tensile_strength concerning a positive electrode sheet and a negative electrode sheet shall be 60 g / cm or less in order to improve the safety | security of a lithium secondary battery. The tension applied to the separator is preferably 40 g / cm or less. The tension applied to the positive electrode sheet and the negative electrode sheet can be set to 0 g / cm, respectively. And it is preferable that the tension | tensile_strength concerning a positive electrode sheet and a negative electrode sheet is made substantially the same.
[0010]
Next, a winding method that can be used in the production method of the present invention will be described.
The winding method is not particularly limited as long as the tension applied to one or more of the positive electrode sheet and the negative electrode sheet can be controlled to be constant, and a commonly used winding device can be used. When the tension applied to the positive electrode sheet and the negative electrode sheet is wound under non-uniform conditions, the safety of the lithium secondary battery is lowered. This is probably because the positive electrode sheet and the negative electrode sheet expand and contract during charging and discharging, and the separator is damaged by the frictional force generated between them. As a manufacturing method of the lithium secondary battery of the present invention, the electrode mixture is used as a current collector so that a portion of the positive electrode sheet or the negative electrode sheet on the outermost peripheral side where the electrode mixture is not applied becomes long. After winding, wind at a constant tension from the beginning of winding until the end of the part where the electrode mixture is applied is wound, then cut the unnecessary current collector, and further Specific examples include a method of winding the separator around the outer periphery and cutting the separator, and then fixing the end of the separator with an adhesive tape. In order to wind the positive electrode sheet or the negative electrode sheet at a tension of 0 g / cm, the positive electrode sheet or the negative electrode sheet is placed on the separator, and the tension is applied only to the separator.
[0011]
The electrode mixture is applied to the current collector so that the portion of the negative electrode sheet that is not the outermost peripheral side or the current collector electrode mixture of the positive electrode sheet is not applied, and the electrode mixture is applied from the beginning of winding. It may be wound in a state of applying a certain tension until the end of the coated part is wound, but in this case, it is necessary to wind one extra turn, which decreases the battery capacity. Therefore, it is not preferable.
[0012]
In the method for producing a lithium secondary battery and the lithium secondary battery of the present invention, two separators can be used when winding the electrode group, and the separator can be wound on the positive electrode sheet side and the negative electrode sheet side. Using a separator, place the positive electrode sheet on one end from the center of the long strip-shaped separator, and place the negative electrode sheet on the opposite side of the separator from the side where the positive electrode sheet is installed from the center to the other end of the separator. It can also arrange | position and can be wound from the center part of a separator by folding at the center part of a separator. When using two separators, the tension of each separator can be wound with different tension values at both ends when using one separator, but the two tensions are substantially the same. Some are preferred.
[0013]
The external shape of the electrode group in the present invention is not necessarily cylindrical, and a cross section cut in a direction perpendicular to the winding axis may be an ellipse or a rectangle. The shape of the lithium secondary battery of the present invention is not particularly limited, and may be any of a paper type, a coin type, a cylindrical type, a rectangular shape, and the like.
[0014]
Next, the lithium secondary battery manufactured by the manufacturing method of the present invention will be described.
As the positive electrode sheet used in the production method of the present invention, a sheet in which an electrode mixture containing a positive electrode active material, a conductive material and a binder is supported on a current collector is usually used. As the positive electrode active material, a material that can be doped / dedoped with lithium ions, a carbonaceous material as a conductive material, and a thermoplastic resin as a binder is preferable. Specifically, V, Mn, Examples thereof include lithium composite oxides containing at least one transition metal such as Fe, Co, and Ni. Among them, a layered structure based on an α-NaFeO 2 type structure such as lithium cobaltate, lithium nickelate, or a part of nickel of lithium nickelate substituted with another element is preferable in that the average discharge potential is high. Examples thereof include lithium composite oxides and lithium composite oxides based on a spinel structure such as lithium manganese spinel.
[0015]
A thermoplastic resin is used as the binder used in the production of the positive electrode sheet. Specifically, polyvinylidene fluoride, a copolymer of vinylidene fluoride, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene, and the like. Copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, ethylene-tetrafluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, thermoplastic polyimide, carboxymethylcellulose, Examples thereof include polyethylene and polypropylene.
[0016]
A carbonaceous material is used as the conductive agent used in the production of the positive electrode sheet, and specific examples include natural graphite, artificial graphite, cokes, and carbon black. As the conductive material, each may be used alone, for example, artificial graphite and carbon black may be mixed and used.
[0017]
As the current collector used for the production of the positive electrode sheet, Al, stainless steel or the like can be used, but Al is preferable in that it is lightweight, inexpensive and easy to process into a thin film. As a method of applying the positive electrode mixture containing the positive electrode active material to the current collector, pressure bonding is performed, or a paste is formed using a solvent or the like, and is applied onto the current collector and then pressed and pressed. A method is mentioned.
[0018]
For the negative electrode sheet used in the production method of the present invention, a material in which a material capable of doping and dedoping lithium ions is supported on a current collector as an electrode mixture containing a binder, or lithium metal, a lithium alloy, or the like is used. Specific examples of materials that can be doped / dedoped with lithium ions include carbon such as natural graphite, artificial graphite, cokes, carbon black, pyrolytic carbons, carbon fibers, and fired organic polymer compounds. Examples thereof include chalcogen compounds such as oxides and sulfides that dope and dedope lithium ions at a potential lower than that of the positive electrode. As a carbonaceous material, a carbonaceous material mainly composed of graphite materials such as natural graphite and artificial graphite, because it has a high potential flatness and a low average discharge potential, so that a large energy density can be obtained when combined with a positive electrode. Is preferred.
[0019]
Further, in the case of using in combination with a liquid electrolyte, when the liquid electrolyte does not contain ethylene carbonate, it is preferable to use a negative electrode mixture containing polyethylene carbonate because cycle characteristics and large current discharge characteristics are improved. The shape of the carbonaceous material may be, for example, a flake shape such as natural graphite, a spherical shape such as mesocarbon microbeads, a fibrous shape such as graphitized carbon fiber, or an aggregate of fine powder. Thus, a thermoplastic resin as a binder can be added. Examples of the thermoplastic resin include polyvinylidene fluoride, polyvinylidene fluoride copolymer, vinylidene fluoride-hexafluoropropylene-terolafluoroethylene copolymer, thermoplastic polyimide, carboxymethyl cellulose, polyethylene, and polypropylene. . Examples of the chalcogen compounds such as oxides and sulfides used as the negative electrode include crystalline or non-crystalline materials mainly composed of groups 13, 14 and 15 of the periodic table such as amorphous compounds mainly composed of tin oxide. Examples thereof include crystalline oxides. Also for these, a carbonaceous material as a conductive material and a thermoplastic resin as a binder can be added as necessary.
[0020]
As the negative electrode current collector used for the negative electrode sheet, Cu, Ni, stainless steel, and the like can be used. However, Cu is preferable because it is difficult to form an alloy with lithium and it is easy to process into a thin film. The method of supporting the negative electrode mixture on the negative electrode current collector is the same as that of the positive electrode, and is pressure-bonded by press molding or pasting using a solvent or the like, coating and drying the current collector, and pressing. The method of doing is mentioned.
[0021]
In the manufacturing method of the present invention, a separator having a shutdown function is used. Furthermore, it is desirable for the separator to have a layer having a shutdown function and a heat-resistant porous layer made of a heat-resistant resin in order to improve battery safety.
[0022]
The layer having a shutdown function is not particularly limited as long as it has a shutdown function, but is usually a porous layer made of a thermoplastic resin. Since the shutdown layer is preferably a substantially non-porous layer at a temperature of 80 ° C. to 180 ° C., the thermoplastic resin forming the shutdown layer is softened and porous at 80 to 180 ° C. A thermoplastic resin that closes the voids and does not dissolve in the electrolyte is preferable. Specific examples include polyolefin and thermoplastic polyurethane. The polyolefin is more preferably at least one thermoplastic resin selected from polyethylene such as low density polyethylene, high density polyethylene, and ultrahigh molecular weight polyethylene, polypropylene, and the like.
[0023]
When the size of the air gap in the shutdown layer or the air gap can be approximated to a sphere, the diameter of the sphere (hereinafter sometimes referred to as a pore diameter) is preferably 3 μm or less, and more preferably 1 μm or less. The porosity of the shutdown layer is preferably 30 to 80% by volume, more preferably 40 to 70% by volume, and the thickness is preferably 3 to 30 μm, more preferably 5 to 20 μm.
[0024]
The heat resistant porous layer is preferably made of a heat resistant resin. The heat-resistant resin for forming the heat-resistant porous layer in the present invention is at least one selected from resins having a deflection temperature under load of 18.6 kg / cm 2 measured according to JIS K 7207 at 100 ° C. or higher. The heat resistant resin is preferred.
[0025]
Specific examples of the resin having a deflection temperature under 100 ° C. include polyimide, polyamideimide, aramid, polycarbonate, polyacetal, polysulfone, polyphenylsulfide, polyetheretherketone, aromatic polyester, polyethersulfone, and polyether. An imide etc. are mentioned.
[0026]
The pore size or pore size of the heat resistant porous layer is preferably 3 μm or less, more preferably 1 μm or less. Moreover, 30-80 volume% is preferable and, as for the porosity of a heat resistant porous layer, More preferably, it is 40-70 volume%. The thickness is preferably 1 to 20 μm, more preferably 2 to 10 μm.
[0027]
As the non-aqueous electrolyte solution used in the lithium secondary battery of the present invention, for example, a non-aqueous electrolyte solution in which a lithium salt is dissolved in an organic solvent can be used. Examples of lithium salts include LiClO 4 , LiPF 6 , LiAsF 6 , LiSbF 6 , LiBF 4 , LiCF 3 SO 3 , LiN (SO 2 CF 3 ) 2 , LiC (SO 2 CF 3 ) 3 , Li 2 B 10 Cl 10 , One or a mixture of two or more of lower aliphatic carboxylic acid lithium salts, LiAlCl 4 and the like can be mentioned. The lithium salt is selected from the group consisting of LiPF 6 containing fluorine, LiAsF 6 , LiSbF 6 , LiBF 4 , LiCF 3 SO 3 , LiN (CF 3 SO 2 ) 2 , and LiC (CF 3 SO 2 ) 3 among these. It is preferable to use one containing at least one selected from the above.
[0028]
Examples of the organic solvent used in the non-aqueous electrolyte include propylene carbonate, ethylene carbonate, vinylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, 4-trifluoromethyl-1,3-dioxolan-2-one, 1, Carbonates such as 2-di (methoxycarbonyloxy) ethane; 1,2-dimethoxyethane, 1,3-dimethoxypropane, pentafluoropropyl methyl ether, 2,2,3,3-tetrafluoropropyl difluoromethyl ether, tetrahydrofuran Ethers such as 2-methyltetrahydrofuran; esters such as methyl formate, methyl acetate and γ-butyrolactone; nitriles such as acetonitrile and butyronitrile; N, N-dimethylformamide; Amides such as N, dimethylacetamide; carbamates such as 3-methyl-2-oxazolidone; sulfur-containing compounds such as sulfolane, dimethyl sulfoxide, 1,3-propane sultone, or the above organic solvents with fluorine substituents Those introduced may be mentioned, and usually two or more of these are mixed and used.
[0029]
Among these, a mixed solvent containing carbonates is preferable, and a mixed solvent of cyclic carbonate and acyclic carbonate or cyclic carbonate and ether is more preferable. The mixed solvent of cyclic carbonate and non-cyclic carbonate has a wide operating temperature range, excellent load characteristics, and is hardly decomposable even when a graphite material such as natural graphite or artificial graphite is used as the negative electrode active material. In addition, a mixed solvent containing ethylene carbonate, dimethyl carbonate and ethyl methyl carbonate is preferable.
[0030]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by these.
[0031]
Example 1
(1) Preparation of positive electrode sheet 1 part by weight of carboxymethylcellulose is dissolved in water, and a 60% by weight aqueous dispersion of polytetrafluoroethylene and acetylene black 2.5 so that the polytetrafluoroethylene is 4.5 parts by weight. Part by weight and 92 parts by weight of lithium cobaltate powder as a positive electrode active material were dispersed and kneaded to obtain a paste for a positive electrode mixture. The paste was applied to predetermined portions on both sides of a 20 μm thick Al foil serving as a positive electrode current collector, followed by drying, roll pressing, and slitting to obtain a positive electrode sheet. The uncoated portion of the positive electrode mixture was 2 cm, and an aluminum lead was resistance-welded to the end.
[0032]
(2) Production of negative electrode sheet 2 parts by weight of carboxymethylcellulose was dissolved in water, and 98 parts by weight of natural graphite was dispersed and kneaded to obtain a paste of an electrode mixture for negative electrode. The paste was applied to predetermined portions on both sides of a 12 μm-thick Cu foil serving as a negative electrode current collector, followed by drying, roll pressing, and slitting to obtain a negative electrode sheet. Non-coated portions of the negative electrode mixture were prepared as 2 cm and 30 cm, and a nickel lead was resistance welded to the end of the negative electrode mixture applied side.
[0033]
(3) Preparation of separator provided with heat-resistant porous layer 3-a Synthesis of para-aramid solution Polyagitator using a 5-liter (l) separable flask having a stirring blade, a thermometer, a nitrogen inlet tube and a powder addition port (Paraphenylene terephthalamide) (hereinafter abbreviated as PPTA) was synthesized. The flask was sufficiently dried, charged with 4200 g of NMP, 272.65 g of calcium chloride dried at 200 ° C. for 2 hours was added, and the temperature was raised to 100 ° C. After calcium chloride was completely dissolved, the temperature was returned to room temperature, and 132.91 g of paraphenylenediamine (hereinafter abbreviated as PPD) was added and completely dissolved. While maintaining this solution at 20 ± 2 ° C., 243.32 g of terephthalic acid dichloride (hereinafter abbreviated as TPC) was added in 10 divided portions every about 5 minutes. Thereafter, the solution was aged for 1 hour while maintaining at 20 ± 2 ° C., and stirred for 30 minutes under reduced pressure in order to remove bubbles. The obtained polymerization liquid showed optical anisotropy. A part was sampled, reprecipitated with water and taken out as a polymer, and the intrinsic viscosity of the obtained PPTA was measured and found to be 1.97 dl / g.
Next, 100 g of this polymerization solution was weighed into a 500 ml separable flask having a stirring blade, a thermometer, a nitrogen inlet tube and a liquid addition port, and the NMP solution was gradually added. Finally, a PPTA solution having a PPTA concentration of 2.0% by weight was prepared, and this was used as a P solution.
[0034]
(2) Application of para-aramid solution and production of separator As a shutdown layer, PE (polyethylene) porous membrane (film thickness 16 μm, air permeability 400 sec / 100 cc, average pore radius (mercury intrusion method) 0.04 μm) Was used. Using a bar coater manufactured by Tester Sangyo Co., Ltd. (gap: 200 μm), P solution, which is a heat-resistant resin solution, is applied onto the PE porous membrane placed on a glass plate and held in a draft in the laboratory for about 20 minutes. As a result, PPTA was precipitated, and a cloudy film was obtained on the PE porous film. The PE porous membrane with the membrane attached thereto was immersed in ion-exchanged water, and after 5 minutes, the membrane was peeled from the glass plate, washed thoroughly with flowing ion-exchanged water, and then freed of water. . This membrane was sandwiched between nylon cloths and further sandwiched between aramid felts. In a state where the PE porous membrane with the film attached is sandwiched between nylon cloth and aramid felt, place an aluminum plate, cover it with nylon film, seal the nylon film and aluminum plate with gum, A conduit for decompression was attached. A composite in which the whole is put into a heat oven and the membrane is dried while reducing the pressure at 60 ° C., and a shutdown layer made of a PE porous membrane and a heat resistant porous layer made of an aramid porous membrane (thickness: 5 μm) are laminated. A film (thickness 21 μm) was obtained and used as a separator.
[0035]
(4) Production of Cylindrical Battery The positive electrode sheet, negative electrode sheet (negative electrode electrode mixture uncoated portion 30 cm) and separator produced as described above were arranged in the order of positive electrode sheet, separator, negative electrode sheet, and negative electrode. The mixture uncoated portion was laminated so as to be the outermost periphery, and wound from one end to form an electrode group. At this time, the negative electrode sheet serving as the outermost periphery was cut with the separator after applying tension until the electrode mixture coating portion for negative electrode was completely wound and the negative electrode lead was wound around the separator. Then, after winding up so that there was no looseness in the outermost peripheral part, the outermost peripheral separator was fixed with tape. At this time, the tension on the positive electrode sheet and the negative electrode sheet was 60 g / cm, and the tension on the separator was 33 g / cm.
The above electrode element is inserted into a battery can, and LiPF 6 is dissolved in a mixed solution of ethylene carbonate, dimethyl carbonate and ethyl methyl carbonate in a volume ratio of 16:10:74 as a non-aqueous electrolyte solution so as to be 1 mol / liter. And a battery lid that also serves as a positive electrode terminal was caulked through a gasket to obtain a 18650 size cylindrical battery.
[0036]
Moreover, the nail penetration test was implemented about the two cylindrical batteries obtained in this way in the overcharge state of 4.45V. As a result, the battery tested showed only a gradual temperature rise despite the severe state of overcharging.
[0037]
Example 2
An electrode mixture in the battery was wound in the same manner as in Example 1 except that a non-coated portion of the electrode mixture for negative electrode of the negative electrode sheet was 2 cm and no tension was applied to the positive electrode sheet and the negative electrode sheet. The part tension was constant (0 g / cm), and a 18650 size cylindrical battery was obtained. About this cylindrical battery, the nail penetration test was implemented in the overcharge state of 4.5V. As a result, the battery used for the test showed only a gradual temperature rise as in Example 1, despite the more severe state than Example 1 of 4.5 V overcharge.
[0038]
Comparative Example 1
Use a negative electrode sheet with a 2 cm uncoated portion of the negative electrode mixture, and wind it in the same manner as in Example 1 until the outermost circumference is left, winding the outermost circumference without applying tension. As a result, an 18650 size cylindrical battery having different tensions between the inner peripheral portion and the outermost peripheral portion was obtained. The cylindrical battery was subjected to a nail penetration test in the same manner as in Example 1. As a result, a significant temperature increase was observed.
[0039]
【The invention's effect】
According to the present invention, a lithium secondary battery having higher safety than before can be produced, and therefore the present invention is extremely useful industrially.
Claims (4)
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| JP2003145858A JP4569074B2 (en) | 2003-05-23 | 2003-05-23 | Method for manufacturing lithium secondary battery |
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| JP4584307B2 (en) * | 2005-03-31 | 2010-11-17 | パナソニック株式会社 | Lithium secondary battery |
| JP2007123237A (en) * | 2005-09-29 | 2007-05-17 | Sanyo Electric Co Ltd | Nonaqueous electrolyte battery, electrode for nonaqueous electrolyte battery, and manufacturing method of this electrode for nonaqueous electrolyte battery |
| JP2007123238A (en) * | 2005-09-29 | 2007-05-17 | Sanyo Electric Co Ltd | Nonaqueous electrolyte battery, separator for nonaqueous electrolyte battery, and manufacturing method of this separator |
| JP4946006B2 (en) * | 2005-11-04 | 2012-06-06 | 東レ株式会社 | Composite porous membrane and method for producing the same |
| JP5095121B2 (en) | 2006-04-28 | 2012-12-12 | パナソニック株式会社 | Nonaqueous electrolyte secondary battery separator and nonaqueous electrolyte secondary battery |
| US7892672B2 (en) | 2007-06-06 | 2011-02-22 | Teijin Limited | Polyolefin microporous membrane base for nonaqueous secondary battery separator, method for producing the same, nonaqueous secondary battery separator and nonaqueous secondary battery |
| WO2009157263A1 (en) * | 2008-06-23 | 2009-12-30 | シャープ株式会社 | Lithium ion secondary battery |
| JPWO2010082229A1 (en) * | 2009-01-14 | 2012-06-28 | パナソニック株式会社 | Method for producing non-aqueous electrolyte secondary battery |
| JP5504800B2 (en) | 2009-03-23 | 2014-05-28 | 住友化学株式会社 | Lithium composite metal oxide and positive electrode active material |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09161757A (en) * | 1995-12-12 | 1997-06-20 | Sony Corp | Multilayered nonaqueous electrolyte secondary battery |
| JP2000100408A (en) * | 1998-09-21 | 2000-04-07 | Sumitomo Chem Co Ltd | Nonaqueous electrolyte secondary battery |
| JP2001202986A (en) * | 1999-11-08 | 2001-07-27 | Matsushita Electric Ind Co Ltd | Winding method and device for spiral electrode group and battery using the device |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09161757A (en) * | 1995-12-12 | 1997-06-20 | Sony Corp | Multilayered nonaqueous electrolyte secondary battery |
| JP2000100408A (en) * | 1998-09-21 | 2000-04-07 | Sumitomo Chem Co Ltd | Nonaqueous electrolyte secondary battery |
| JP2001202986A (en) * | 1999-11-08 | 2001-07-27 | Matsushita Electric Ind Co Ltd | Winding method and device for spiral electrode group and battery using the device |
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