JP3719139B2 - Non-aqueous electrolyte secondary battery - Google Patents

Description

【００２６】
なお、作製した電極板は、捲回したときに、捲回最内周では捲回方向に正極板が負極板からはみ出すことがなく、また最外周でも捲回方向に正極板が負極板からはみ出すことがないように負極板の長さは正極板の長さよりも１８ｃｍ長くなるようにした。また、捲回方向と垂直方向においても正極活物質塗布部が負極活物質塗布部からはみ出すことがないように、負極活物質塗布部の幅は、正極活物質塗布部の幅よりも５ｍｍ長くした（以下の実施例及び比較例においても同じ。）。
【００２７】
（実施例２）
表１に示すように、実施例２では、マンガン酸リチウムの塗着量を３００ｇ／ｍ^２とし、正極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を２５２μｍ、正極板の長さを５６５ｃｍ、負極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を１６６μｍ、負極板の長さを５８３ｃｍとした以外は実施例１と同様に電池を作製した。
【００２８】
（実施例２−２〜２−５）
表１に示すように、実施例２−２〜実施例２−５では、マンガン酸リチウムのＬｉ／Ｍｎ比をそれぞれ、０．５５、０．５８、０．６０、０．６１とした以外は実施例２と同様に電池を作製した。
【００２９】
（実施例３）
表１に示すように、実施例３では、マンガン酸リチウムの塗着量を３３０ｇ／ｍ^２とし、正極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を２７７μｍ、正極板の長さを５２３ｃｍ、負極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を１８３μｍ、負極板の長さを５４１ｃｍとした以外は実施例１と同様に電池を作製した。
【００３０】
（実施例４）
表１に示すように、実施例４では、実施例１と同様のマンガン酸リチウム粉末と、平均粒子径１８μｍの鱗片状黒鉛（ＬｉＭｎ_２Ｏ_４の二次粒径に対する鱗片状黒鉛の平均粒径：０．９倍）と、ポリフッ化ビニリデンとの配合比を、重量％で９０：３：７とし、正極活物質合剤層（活物質塗布部）の集電体片面あたりのマンガン酸リチウムの塗着量を３００ｇ／ｍ^２、正極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を２５２μｍ、正極板の長さを５６５ｃｍとした。一方、負極板には、負極活物質としてＭＣＭＢを用い、負極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を１６６μｍ、長さを５８３ｃｍとして、電池を作製した。
【００３１】
（実施例５）
表１に示すように、実施例５では、実施例１と同様のマンガン酸リチウム粉末と、平均粒子径１８μｍの鱗片状黒鉛（ＬｉＭｎ_２Ｏ_４の二次粒径に対する鱗片状黒鉛の平均粒径：０．９倍）と、ポリフッ化ビニリデンとの配合比を、重量％で９０：７：３とし、正極活物質合剤層（活物質塗布部）の集電体片面あたりのマンガン酸リチウムの塗着量を３００ｇ／ｍ^２、正極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を２６０μｍ、正極板の長さを５５６ｃｍとした。一方、負極板には、負極活物質としてＭＣＭＢを用い、負極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を１６６μｍ、長さを５７４ｃｍとして、電池を作製した。
【００３２】
（実施例６）
表１に示すように、実施例６では、実施例１と同様のマンガン酸リチウム粉末と、平均粒子径１８μｍの鱗片状黒鉛（ＬｉＭｎ_２Ｏ_４の二次粒径に対する鱗片状黒鉛の平均粒径：０．９倍）と、ケッチェンブラック（ＫＢ）と、ポリフッ化ビニリデンとの配合比を、重量％で９０：４：１：５とし、正極活物質合剤層（活物質塗布部）の集電体片面あたりのマンガン酸リチウムの塗着量を３００ｇ／ｍ^２、正極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を２５２μｍ、正極板の長さを５６５ｃｍとした。一方、負極板には、負極活物質としてＭＣＭＢを用い、負極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を１６６μｍ、長さを５８３ｃｍとして、電池を作製した。
【００３３】
（実施例７）
表１に示すように、実施例７では、実施例１と同様のマンガン酸リチウム粉末と、平均粒子径２μｍの鱗片状黒鉛（ＬｉＭｎ_２Ｏ_４の二次粒径に対する鱗片状黒鉛の平均粒径：０．１倍）と、ケッチェンブラック（ＫＢ）と、ポリフッ化ビニリデンとの配合比を、重量％で９０：４：１：５とし、正極活物質合剤層（活物質塗布部）の集電体片面あたりのマンガン酸リチウムの塗着量を３００ｇ／ｍ^２、正極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を２５２μｍ、正極板の長さを５６５ｃｍとした。一方、負極板には、負極活物質としてＭＣＭＢを用い、負極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を１６６μｍ、長さを５８３ｃｍとして、電池を作製した。
【００３４】
（実施例８）
表１に示すように、実施例８では、実施例１と同様のマンガン酸リチウム粉末と、平均粒子径４μｍの鱗片状黒鉛（ＬｉＭｎ_２Ｏ_４の二次粒径に対する鱗片状黒鉛の平均粒径：０．２倍）と、ケッチェンブラック（ＫＢ）と、ポリフッ化ビニリデンとの配合比を、重量％で９０：４：１：５とし、正極活物質合剤層（活物質塗布部）の集電体片面あたりのマンガン酸リチウムの塗着量を３００ｇ／ｍ^２、正極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を２５２μｍ、正極板の長さを５６５ｃｍとした。一方、負極板には、負極活物質としてＭＣＭＢを用い、負極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を１６６μｍ、長さを５８３ｃｍとして、電池を作製した。
【００３５】
（実施例９）
表１に示すように、実施例９では、実施例１と同様のマンガン酸リチウム粉末と、平均粒子径１０μｍの鱗片状黒鉛（ＬｉＭｎ_２Ｏ_４の二次粒径に対する鱗片状黒鉛の平均粒径：０．５倍）と、ケッチェンブラック（ＫＢ）と、ポリフッ化ビニリデンとの配合比を、重量％で９０：４：１：５とし、正極活物質合剤層（活物質塗布部）の集電体片面あたりのマンガン酸リチウムの塗着量を３００ｇ／ｍ^２、正極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を２５２μｍ、長さを５６５ｃｍとした。一方、負極板には、負極活物質としてＭＣＭＢを用い、負極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を１６６μｍ、長さを５８３ｃｍとして、電池を作製した。
【００３６】
（実施例１０）
表１に示すように、実施例１０では、実施例１と同様のマンガン酸リチウム粉末と、平均粒子径１６μｍの鱗片状黒鉛（ＬｉＭｎ_２Ｏ_４の二次粒径に対する鱗片状黒鉛の平均粒径：０．８倍）と、ケッチェンブラック（ＫＢ）と、ポリフッ化ビニリデンとの配合比を、重量％で９０：４：１：５とし、正極活物質合剤層（活物質塗布部）の集電体片面あたりのマンガン酸リチウムの塗着量を３００ｇ／ｍ^２、正極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を２５２μｍ、長さを５６５ｃｍとした。一方、負極板には、負極活物質としてＭＣＭＢを用い、負極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を１６６μｍ、長さを５８３ｃｍとして、電池を作製した。
【００３７】
（実施例１１）
表１に示すように、実施例１１では、実施例１と同様のマンガン酸リチウム粉末と、平均粒子径１０μｍの鱗片状黒鉛（ＬｉＭｎ_２Ｏ_４の二次粒径に対する鱗片状黒鉛の平均粒径：０．５倍）と、アセチレンブラック（ＡＢ）と、ポリフッ化ビニリデンとの配合比を、重量％で９０：４：１：５とし、正極活物質合剤層（活物質塗布部）の集電体片面あたりのマンガン酸リチウムの塗着量を３００ｇ／ｍ^２、正極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を２５２μｍ、長さを５６５ｃｍとした。一方、負極板には、負極活物質としてＭＣＭＢを用い、負極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を１６６μｍ、長さを５８３ｃｍとして、電池を作製した。
【００３８】
（実施例１２）
表１に示すように、実施例１２では、正極活物質として一次粒子径約１〜２μｍ、二次粒子径約２０μｍ、ＬｉとＭｎの原子比（Ｌｉ／Ｍｎ比）０．５５のマンガン酸リチウム（ＬｉＭｎ_２Ｏ_４）粉末と、平均粒子径１０μｍの鱗片状黒鉛（ＬｉＭｎ_２Ｏ_４の二次粒径に対する鱗片状黒鉛の平均粒径：０．５倍）と、アセチレンブラック（ＡＢ）と、ポリフッ化ビニリデンとの配合比を、重量％で９０：４：１：５とし、正極活物質合剤層（活物質塗布部）の集電体片面あたりのマンガン酸リチウムの塗着量を３００ｇ／ｍ^２、正極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を２５２μｍ、長さを５６５ｃｍとした。一方、負極板には、負極活物質としてＭＣＭＢを用い、負極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を１６６μｍ、長さを５８３ｃｍとして、電池を作製した。
【００３９】
（実施例１３）
表１に示すように、実施例１３では、正極活物質として一次粒子径約１〜２μｍ、二次粒子径約２０μｍ、ＬｉとＭｎの原子比（Ｌｉ／Ｍｎ比）０．５８のマンガン酸リチウム（ＬｉＭｎ_２Ｏ_４）粉末と、平均粒子径１０μｍの鱗片状黒鉛（ＬｉＭｎ_２Ｏ_４の二次粒径に対する鱗片状黒鉛の平均粒径：０．５倍）と、アセチレンブラック（ＡＢ）と、ポリフッ化ビニリデンとの配合比を、重量％で９０：４：１：５とし、正極活物質合剤層（活物質塗布部）の集電体片面あたりのマンガン酸リチウムの塗着量を３００ｇ／ｍ^２、正極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を２５２μｍ、長さを５６５ｃｍとした。一方、負極板には、負極活物質としてＭＣＭＢを用い、負極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を１６６μｍ、長さを５８３ｃｍとして、電池を作製した。
【００４０】
（実施例１４）
表１に示すように、実施例１４では、正極活物質として一次粒子径約１〜２μｍ、二次粒子径約２０μｍ、ＬｉとＭｎの原子比（Ｌｉ／Ｍｎ比）０．６０のマンガン酸リチウム（ＬｉＭｎ_２Ｏ_４）粉末と、平均粒子径１０μｍの鱗片状黒鉛（ＬｉＭｎ_２Ｏ_４の二次粒径に対する鱗片状黒鉛の平均粒径：０．５倍）と、アセチレンブラック（ＡＢ）と、ポリフッ化ビニリデンとの配合比を、重量％で９０：４：１：５とし、正極活物質合剤層（活物質塗布部）の集電体片面あたりのマンガン酸リチウムの塗着量を３００ｇ／ｍ^２、正極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を２５２μｍ、長さを５６５ｃｍとした。一方、負極板には、負極活物質としてＭＣＭＢを用い、負極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を１６６μｍ、長さを５８３ｃｍとして、電池を作製した。
【００４１】
（実施例１５）
表１に示すように、実施例１５では、正極活物質として一次粒子径約１〜２μｍ、二次粒子径約２０μｍ、ＬｉとＭｎの原子比（Ｌｉ／Ｍｎ比）０．６１のマンガン酸リチウム（ＬｉＭｎ_２Ｏ_４）粉末と、平均粒子径１０μｍの鱗片状黒鉛（ＬｉＭｎ_２Ｏ_４の二次粒径に対する鱗片状黒鉛の平均粒径：０．５倍）と、アセチレンブラック（ＡＢ）と、ポリフッ化ビニリデンとの配合比を、重量％で９０：４：１：５とし、正極活物質合剤層（活物質塗布部）の集電体片面あたりのマンガン酸リチウムの塗着量を３００ｇ／ｍ^２、正極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を２５２μｍ、長さを５６５ｃｍとした。一方、負極板には、負極活物質としてＭＣＭＢを用い、負極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を１６６μｍ、長さを５８３ｃｍとして、電池を作製した。
【００４２】
（実施例１６）
表１に示すように、実施例１６では、実施例１と同様のマンガン酸リチウム粉末と、平均粒子径１０μｍの鱗片状黒鉛（ＬｉＭｎ_２Ｏ_４の二次粒径に対する鱗片状黒鉛の平均粒径：０．５倍）と、アセチレンブラック（ＡＢ）と、ポリフッ化ビニリデンとの配合比を、重量％で９０：４：１：５とし、正極活物質合剤層（活物質塗布部）の集電体片面あたりのマンガン酸リチウムの塗着量を３００ｇ／ｍ^２、正極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を２５２μｍ、長さを６０５ｃｍとした。一方、負極板には、負極活物質として非晶質炭素を用い、負極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を１３３μｍ、長さを６２３ｃｍとして、電池を作製した。
【００４３】
（実施例１６−２〜１６−５）
表１に示すように、実施例１６−２〜実施例１６−５では、マンガン酸リチウムのＬｉ／Ｍｎ比をそれぞれ、０．５５、０．５８、０．６０、０．６１とした以外は実施例１６と同様に電池を作製した。
【００４４】
（実施例１７）
表１に示すように、実施例１７では、実施例１と同様のマンガン酸リチウム粉末と、平均粒子径１０μｍの鱗片状黒鉛（ＬｉＭｎ_２Ｏ_４の二次粒径に対する鱗片状黒鉛の平均粒径：０．５倍）と、ポリフッ化ビニリデンとの配合比を、重量％で９０：５：５とし、正極活物質合剤層（活物質塗布部）の集電体片面あたりのマンガン酸リチウムの塗着量を３００ｇ／ｍ^２、正極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を２５２μｍ、長さを６０５ｃｍとした。一方、負極板には、負極活物質として非晶質炭素を用い、負極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を１３３μｍ、長さを６２３ｃｍとして、電池を作製した。
【００４５】
（実施例１７−２〜１７−５）
表１に示すように、実施例１７−２〜実施例１７−５では、マンガン酸リチウムのＬｉ／Ｍｎ比をそれぞれ、０．５５、０．５８、０．６０、０．６１とした以外は実施例１７と同様に電池を作製した。
【００４６】
（比較例１）
表１に示すように、比較例１では、マンガン酸リチウムの塗着量を２６０ｇ／ｍ^２とし、正極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を２１８μｍ、長さを６３３ｃｍとし、負極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を１４４μｍ、負極板の長さを６５１ｃｍとした以外は実施例１と同様の電池を作製した。
【００４７】
（比較例２）
表１に示すように、比較例２では、マンガン酸リチウムの塗着量を３４０ｇ／ｍ^２とし、正極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を２８５μｍ、長さを５１１ｃｍとし、負極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を１８９μｍ、負極板の長さを５２９ｃｍとした以外は実施例１と同様の電池を作製した。
【００４８】
（比較例３）
表１に示すように、比較例３では、実施例１と同様のマンガン酸リチウム粉末と、平均粒子径１８μｍの鱗片状黒鉛（ＬｉＭｎ_２Ｏ_４の二次粒径に対する鱗片状黒鉛の平均粒径：０．９倍）と、ポリフッ化ビニリデンとの配合比を、重量％で９１：２：７とし、正極活物質合剤層（活物質塗布部）の集電体片面あたりのマンガン酸リチウムの塗着量を３００ｇ／ｍ^２、正極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を２４９μｍ、正極板の長さを５６８ｃｍとし、負極活物質としてＭＣＭＢを用い、負極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を１６６μｍ、負極板の長さを５８６ｃｍとして、電池を作製した。
【００４９】
（比較例４）
表１に示すように、比較例４では、実施例１と同様のマンガン酸リチウム粉末と、平均粒子径１８μｍの鱗片状黒鉛（ＬｉＭｎ_２Ｏ_４の二次粒径に対する鱗片状黒鉛の平均粒径：０．９倍）と、ポリフッ化ビニリデンとの配合比を、重量％で８６：８：６とし、正極活物質合剤層（活物質塗布部）の集電体片面あたりのマンガン酸リチウムの塗着量を３００ｇ／ｍ^２、正極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を２６３μｍ、正極板の長さを５５３ｃｍとした。一方、負極板には、負極活物質としてＭＣＭＢを用い、負極活物質合剤層（活物質塗布部）の厚さ（集電体厚さは含まない。）を１６６μｍ、負極板の長さを５７１ｃｍとして、電池を作製した。
【００５０】
＜試験・評価＞
次に、以上のようにして作製した実施例及び比較例の各電池について、以下の一連の試験を行った。
【００５１】
実施例及び比較例の各電池を、充電した後放電し、放電容量を測定した。充電条件は、４．２Ｖ定電圧、制限電流８０Ａ、３．５時間とした。放電条件は、２０Ａ定電流、終止電圧２．７Ｖとした。
【００５２】
また、上記条件で充電状態の電池の放電出力を測定した。測定条件は、２０Ａ、４０Ａ、８０Ａ、各放電電流で５秒目の電圧を読み取り、横軸電流値に対して縦軸にプロットし、３点を結ぶ近似直線が、２．７Ｖと交差するところの電流値と、２．７Ｖとの積を出力とした。
【００５３】
更に、実施例、比較例の各電池を、上記条件で充放電を１００回繰り返した後、出力（容量）を測定し、初期の出力に対する維持率を百分率で示した。当然のことながら、この維持率が高いほうが寿命特性がよいことになる。
【００５４】
これら充電、放電、出力の測定は、いずれも環境温度２５±1°Ｃの雰囲気で行った。
【００５５】
その後、作製した電池を、常温で、８０Ａ定電流で連続充電し、電池挙動を観察した。その結果を下表２に示す。現象は、開裂弁開裂の後、電解液の揮発物からなるガス放出が起こる。このガス放出の程度を比較するために、現象発生直後の電池表面温度を測定した。また、ガス放出後、電池容器の変形の有無を確認した。なお、表２において、「○」は電池容器の変形が全く認められなかったもの、「△」は電池容器の若干の変形が認められたもの、「×」は電池容器が大きく変形したものを示している。
【００５６】
【表２】

【００５７】
表２に示すように、実施例１〜実施例５の電池では、高容量、高出力な電池が得られ、かつ、連続充電時の電池挙動も穏やかなものであった。このときの電池の表面温度は１４０°Ｃ〜２１０°Ｃであった。一方、マンガン酸リチウムの塗着量が２７０ｇ／ｍ^２を下回った比較例1の電池は高容量、高出力な電池が得られるものの、連続充電時の電池挙動が電池の変形を伴った激しいものとなり、電池表面温度は３００°Ｃを超える結果となった。逆に、マンガン酸リチウムの塗着量が３３０ｇ／ｍ^２を上回った比較例２の電池は、連続充電時の電池挙動は穏やかであったが、出力の低下を伴い、電気自動車用電池としてはふさわしくない結果となった。同様に、比較例３の電池は、正極導電材の黒鉛の量が３重量％を下回っており、出力の低下を招く結果となった。一方、正極導電材の黒鉛の量が７重量％を上回っている比較例４の電池では、高容量、高出力な電池が得られるものの、連続充電時の電池挙動は、電池の変形を伴った激しいものとなり、電池表面温度は、３００°Ｃとなる結果となった。
【００５８】
正極導電材に黒鉛と無定型炭素を混合して用いた実施例６〜実施例１６−５の電池では、出力の高い電池を得ることができた。無定型炭素にケッチェンブラックを用いた実施例６〜実施例１０の電池では、正極活物質のマンガン酸リチウムの二次粒子径に対する導電材黒鉛の粒子径の比が、０．２〜０．８である実施例８〜実施例１０の電池が、中でもより高出力が得られている。マンガン酸リチウムの二次粒子径に対する導電材黒鉛の粒子径の比が、０．２を下回っている実施例７の電池では、連続充電時の電池表面温度が２００°Ｃと、実施例８〜１０の電池と比べて若干高い。
【００５９】
無定型炭素にアセチレンブラックを用いた実施例１１〜実施例１６−５の電池では、より高出力が得られており、かつ、１００回充放電後における出力維持率も高い。
【００６０】
マンガン酸リチウムのＬｉ／Ｍｎ比が、０．５５以上である実施例１２〜実施例１４、実施例２−２〜実施例２−４、実施例１６−２〜実施例１６−４、実施例１７−２〜実施例１７−４の電池は、出力維持率が極めて高い。ところが、マンガン酸リチウムのＬｉ／Ｍｎ比が０．６０を上回る実施例１５、実施例２−５、実施例１６−５、実施例１７−５の電池では、容量の低下を伴う結果となり、Ｌｉ／Ｍｎ比は、０．５５〜０．６０の範囲が好ましいことがわかる。
【００６１】
負極板に非晶質炭素を用いた実施例１６、実施例１６−２〜実施例１６−５、実施例１７、実施例１７−２〜実施例１７−５の電池は、極めて高い出力、かつ、極めて高い出力維持率、最も低い連続充電時の電池表面温度が得られた。従って、これら実施例１６、１６−２〜１６−５、１７、１７−２〜１７−５の電池は、高容量、高出力で、かつ、安全性に優れる、全体バランスのとれた電池であるということができる。
【００６２】
以上のように、本実施形態の円筒形リチウムイオン電池２０は、電池が異常な状態にさらされた場合の挙動が極めて穏やかで、安全性に優れた電池である。このように、高容量、高出力で、極めて安全性の高い電池は、特に電気自動車の電源に適している。
【００６３】
なお、本実施形態では、電気自動車用電源に用いられる大形の二次電池について例示したが、電池の大きさ、電池容量には限定されず、電池容量としておおむね２０Ａｈ程度の電池に対して本発明は効果を著しく発揮することが確認されている。また、本実施形態では円筒形電池について例示したが、本発明は電池の形状についても限定されず、角形、その他の多角形の電池にも適用可能である。更に、本発明の適用可能な形状としては、上述したように正負外部端子が電池蓋を貫通し電池容器内で軸芯を介して正負外部端子が押し合っている状態の電池以外であっても構わない。このような構造の一例として有底筒状容器（缶）に電池上蓋がカシメによって封口されている構造の電池を挙げることができる。
【００６４】
また、本実施形態では、絶縁被覆に、基材がポリイミドで、その片面にヘキサメタアクリレートからなる粘着剤を塗布した粘着テープを用いた例を示したが、例えば、基材がポリプロピレンやポリエチレン等のポリオレフィンで、その片面又は両面にヘキサメタアクリレートやブチルアクリレート等のアクリル系粘着剤を塗布した粘着テープや、粘着剤を塗布しないポリオレフィンやポリイミドからなるテープ等も好適に使用することができる。
【００６５】
更に、本実施形態では、リチウムイオン電池用の正極にマンガン酸リチウム、負極に非晶質炭素、電解液にエチレンカーボネートとジメチルカーボネートとジエチルカーボネートの体積比１：１：１の混合溶液中へ６フッ化リン酸リチウムを１モル／リットル溶解したものを用いたが、本発明の電池には特に制限はなく、また、導電材、結着剤も通常用いられているいずれのものも使用可能である。なお、一般に、マンガン酸リチウムは、適当なリチウム塩と酸化マンガンとを混合、焼成して合成することができるが、リチウム塩と酸化マンガンの仕込み比を制御することによって所望のＬｉ／Ｍｎ比とすることができる。
【００６６】
また、本実施形態以外で用いることのできるリチウムイオン電池用極板活物質結着剤としては、ポリテトラフルオロエチレン、ポリエチレン、ポリスチレン、ポリブタジエン、ブチルゴム、ニトリルゴム、スチレン／ブタジエンゴム、多硫化ゴム、ニトロセルロース、シアノエチルセルロース、各種ラテックス、アクリロニトリル、フッ化ビニル、フッ化ビニリデン、フッ化プロピレン、フッ化クロロプレン等の重合体及びこれらの混合体などがある。
【００６７】
また更に、本実施形態以外で用いることのできるリチウムイオン電池用正極活物質としては、リチウムを挿入・脱離可能な材料であり、予め十分な量のリチウムを挿入したリチウムマンガン複酸化物が好ましく、スピネル構造を有したマンガン酸リチウムや、結晶中のマンガンやリチウムの一部をそれら以外の元素で置換あるいはドープした材料を使用するようにしてもよい。
【００６８】
更にまた、本実施形態以外で用いることのできるリチウムイオン電池用負極活物質も上記特許請求範囲に記載した事項以外に特に制限はない。例えば、天然黒鉛や、人造の各種黒鉛材、コークス、非晶質炭素などの炭素質材料等でよく、その粒子形状においても、鱗片状、球状、繊維状、塊状等、特に制限されるものではない。
【００６９】
また、非水電解液としては、一般的なリチウム塩を電解質とし、これを有機溶媒に溶解した電解液が用いられる。しかし、用いられるリチウム塩や有機溶媒は特に制限されない。例えば、電解質としては、ＬｉＣｌＯ₄、ＬｉＡｓＦ₆、ＬｉＰＦ₆、ＬｉＢＦ₄、ＬｉＢ（Ｃ₆Ｈ₅）₄、ＣＨ₃ＳＯ₃Ｌｉ、ＣＦ₃ＳＯ₃Ｌｉ等やこれらの混合物を用いることができる。非水電解液有機溶媒としては、プロピレンカーボネート、エチレンカーボネート、１，２−ジメトキシエタン、１，２−ジエトキシエタン、γ−ブチロラクトン、テトラヒドロフラン、１，３−ジオキソラン、４−メチル−１，３−ジオキソラン、ジエチルエーテル、スルホラン、メチルスルホラン、アセトニトリル、プロピオニトニル等またはこれら２種類以上の混合溶媒を用いるようにしてもよく、混合配合比についても限定されるものではない。
【００７０】
【発明の効果】
以上説明したように、本発明によれば、平均粒径０．１μｍ乃至２μｍの一次粒子の集合体で形成された二次粒子からなるスピネル系リチウムマンガン複酸化物と、黒鉛と無定型炭素との混合物の導電材とを含む活物質合剤が帯状集電体の両面にほぼ均等量塗着された正極と充放電によりリチウムイオンを吸蔵・放出可能な負極とを用い、黒鉛の平均粒径を二次粒子の平均粒径の０．２倍乃至０．８倍としたので、高容量、高出力とすることができると共に、リチウムマンガン複酸化物を、集電体片面あたりの塗着量が２７０ｇ／ｍ^２乃至３３０ｇ／ｍ^２とし、かつ、導電材量を３重量％乃至７重量％としたので、内圧開放機構からのガス放出が極めて穏やかに行われるため、高容量、高出力でありながらも、極めて安全性の高い非水電解液二次電池を実現することができる、という効果を得ることができる。
【図面の簡単な説明】
【図１】本発明が適用可能な実施形態の円筒形リチウムイオン電池の断面図である。
【符号の説明】
１ 正極外部端子
１’ 負極外部端子
２ ナット
３ 第１のセラミックワッシャ
３’ 第２のセラミックワッシャ
４ 電池蓋（電池容器の一部）
５ 電池容器
６ 捲回群（電極捲回群）
７ 鍔部
８ 絶縁被覆
９ リード片
１０ 開裂弁（内圧低減機構）
２０ 円筒形リチウムイオン電池（非水電解液二次電池）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a non-aqueous electrolyte secondary battery, and in particular, a positive electrode including a lithium manganese complex oxide composed of secondary particles formed of an aggregate of primary particles having an average particle diameter of 0.1 μm to 2 μm and a conductive material. An electrode winding group in which a positive electrode in which an active material mixture is applied to both sides of a belt-like current collector in an approximately equal amount and a negative electrode capable of inserting and extracting lithium ions by charging and discharging are wound through a separator, The present invention relates to a non-aqueous electrolyte secondary battery housed in a battery container having an internal pressure release mechanism that releases an internal pressure at a predetermined pressure.
[0002]
[Prior art]
Lithium ion secondary batteries, which are representative of non-aqueous electrolyte secondary batteries, are mainly used as power sources for portable devices such as VTR cameras, notebook computers, and mobile phones, taking advantage of the high energy density. The internal structure of this battery is usually a winding type as shown below. The electrode is in the form of a band in which an active material is applied to a metal foil for both the positive electrode and the negative electrode, and the cross section is spirally wound so that the positive electrode and the negative electrode are not in direct contact across the separator, forming a wound group. ing. The wound group is housed in a cylindrical battery can serving as a battery container, and sealed after injecting the electrolyte.
[0003]
A typical cylindrical lithium ion secondary battery has a diameter of 18 mm and a height of 65 mm, which is called 18650 type, and is widely used as a small consumer lithium ion battery. The positive electrode active material of the 18650 type lithium ion secondary battery mainly uses lithium cobaltate, which is characterized by high capacity and long life. The battery capacity is approximately 1.3 Ah to 1.7 Ah, and the output is approximately 10 W. Degree.
[0004]
On the other hand, in the automobile industry, in order to cope with environmental problems, an electric vehicle (EV) having no exhaust gas and a power source completely made of only a battery and a hybrid (power source of both an internal combustion engine and a battery) Electric) The development of automobiles has been accelerated, and some have been put to practical use.
[0005]
Naturally, a battery serving as a power source for an electric vehicle is required to have high output and high energy characteristics. Lithium ion batteries are attracting attention as batteries that meet this requirement. For the popularization of electric vehicles, it is essential to reduce the price of the battery. For this purpose, a low-cost battery material is required. For example, in the case of a positive electrode active material, a resource-rich manganese oxide is used. Particular attention has been paid to improvements aimed at improving battery performance. In addition, batteries for electric vehicles are required to have not only high capacity but also high output that affects acceleration performance and the like, that is, reduction of internal resistance of the battery. With the aim of increasing the electrode reaction area, this requirement can be met by using lithium manganate having a large specific surface area as the positive electrode active material.
[0006]
Specifically, to increase the specific surface area, it is necessary to reduce the particle size of lithium manganate. However, when the particle size is small, there are problems such as powder scattering during the manufacture of the electrode and difficulty in forming a slurry for application to both sides of the current collector. In order to improve this, it can be coped with by using lithium manganate in which secondary particles are formed by agglomerating primary particles having a small particle diameter.
[0007]
[Problems to be solved by the invention]
However, in the case of a lithium ion battery, the higher the capacity and the higher the output, the lower the safety, and in particular, when using lithium manganate aimed at higher output as described above, the battery There is a tendency that the phenomenon when it falls into an abnormal state becomes somewhat intense. High capacity and high output batteries used for power sources for electric vehicles are charged with large currents and discharged with large currents. Therefore, such batteries are used in 18650 type lithium ion batteries in an abnormal state. It is virtually impossible to provide a current interruption mechanism (a kind of disconnection switch) that operates in response to an increase in internal pressure in the battery structure.
[0008]
In the case of an electric vehicle that carries people, overcharging when the charging control system breaks down, battery crash that may occur in case of accidental collision, foreign object piercing, external short circuit Ensuring the safety of the battery itself, such as time, is a very important battery characteristic that is necessary at a minimum. Battery safety means that the behavior of the battery when exposed to abnormal conditions does not cause any physical damage to the person, but minimizes damage to the vehicle. Means.
[0009]
An object of the present invention is to provide a non-aqueous electrolyte secondary battery that has a high capacity and a high output, yet has a very high safety.
[0010]
[Means for Solving the Problems]
In order to solve the above problems, the present invention comprises secondary particles formed of an aggregate of primary particles having an average particle size of 0.1 μm to 2 μm. Spinel Lithium manganese complex oxide and Of a mixture of graphite and amorphous carbon A positive electrode in which a positive electrode active material mixture containing a conductive material was applied to both sides of the belt-like current collector in an approximately equal amount and a negative electrode capable of inserting and extracting lithium ions by charging and discharging were wound through a separator. In the nonaqueous electrolyte secondary battery in which the electrode winding group is housed in a battery container having an internal pressure release mechanism that releases the internal pressure at a predetermined pressure, the amount of the lithium manganese complex oxide applied per one surface of the current collector 270g / m ² ~ 330g / m ² And ,Previous The amount of conductive material contained in the positive electrode active material mixture is 3 to 7% by weight. And the average particle size of the graphite is 0.2 to 0.8 times the average particle size of the secondary particles. It is characterized by that.
[0011]
In the present invention, in order to secure a high-capacity, high-power non-aqueous electrolyte secondary battery, it is composed of secondary particles formed of an aggregate of primary particles having an average particle size of 0.1 μm to 2 μm. Spinel Used is a positive electrode in which a positive electrode active material mixture containing a lithium manganese complex oxide and a conductive material is applied to both sides of a strip current collector in an approximately equal amount, and a negative electrode capable of inserting and extracting lithium ions by charging and discharging. It has been. In addition, a mixture of graphite and amorphous carbon is used as the conductive material, and the average particle size of graphite is 0.2 to 0.8 times the average particle size of the secondary particles. It can be set as a secondary battery. In non-aqueous electrolyte secondary batteries with high capacity and high output, when an abnormal state occurs, a large current charge or discharge state is maintained, and the battery is caused by a chemical reaction between the non-aqueous electrolyte and the active material mixture. A sudden and large amount of gas is generated in the container, increasing the internal pressure of the battery container. Generally, in a non-aqueous electrolyte secondary battery, in order to prevent an increase in internal pressure in the battery container, the battery container has an internal pressure release mechanism that releases the internal pressure at a predetermined pressure. The coating amount per one side of the current collector is 270 g / m ² ~ 330g / m ² In addition, by setting the amount of the conductive material contained in the positive electrode active material mixture to 3 wt% to 7 wt%, the gas release from the internal pressure release mechanism is performed extremely gently. Therefore, according to the present invention, it is possible to realize a non-aqueous electrolyte secondary battery with extremely high safety while having high capacity and high output.
[0012]
In the present invention, If amorphous carbon is acetylene black, a non-aqueous electrolyte secondary battery with higher output can be obtained. Further, when the Li / Mn ratio of the lithium manganese complex oxide is set to 0.55 to 0.60, the output maintenance ratio can be improved without accompanying a decrease in capacity. Furthermore, if amorphous carbon is used as the negative electrode active material, a non-aqueous electrolyte secondary battery with higher output, higher capacity, and higher safety can be obtained.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments in which the present invention is applied to a cylindrical lithium ion battery for EV mounting will be described below with reference to the drawings.
[0014]
(Preparation of positive electrode plate)
As shown in FIG. 1, lithium manganate (LiMn) as a positive electrode active material ₂ O ₄ ) Powder, predetermined carbon described later as a conductive material, and polyvinylidene fluoride (PVdF) as a binder are mixed at a predetermined mixing ratio, and a dispersion solvent N-methyl-2-pyrrolidone (NMP) is added thereto. The kneaded slurry was applied to both surfaces of an aluminum foil (positive electrode current collector) having a thickness of 20 μm. At this time, an uncoated part with a width of 50 mm was left on one side edge in the longitudinal direction of the positive electrode plate. Thereafter, drying, pressing, and cutting were performed to obtain a belt-like positive electrode plate having a width of 300 mm, a predetermined length described later, and a predetermined thickness of the positive electrode active material mixture application portion. The bulk density of the positive electrode active material mixture layer is 2.65 g / cm. ³ It was. A notch was made in the slurry uncoated portion of the positive electrode plate, and the remainder of the notch was used as a lead piece. Adjacent lead pieces were spaced 50 mm apart, and the lead piece width was 10 mm.
[0015]
(Preparation of negative electrode plate)
8 parts by weight of polyvinylidene fluoride as a binder was added to 92 parts by weight of a predetermined carbon powder capable of containing and releasing lithium by charging and discharging, and N-methyl-2-pyrrolidone as a dispersion solvent was added thereto and kneaded. The slurry was applied to both surfaces of a rolled copper foil (negative electrode current collector) having a thickness of 10 μm. At this time, an uncoated part having a width of 50 mm was left on one side edge in the longitudinal direction of the negative electrode plate. Thereafter, drying, pressing, and cutting were performed to obtain a strip-shaped negative electrode plate having a width of 305 mm, a predetermined length described later, and a predetermined thickness of the negative electrode active material application portion. The negative electrode plate was compressed so that the porosity of the negative electrode active material mixture layer was about 35%. A notch was cut into the slurry-uncoated portion of the negative electrode plate in the same manner as the positive electrode plate, and the remainder of the notch was used as a lead piece. Adjacent lead pieces were spaced 50 mm apart, and the lead piece width was 10 mm.
[0016]
(Production of battery)
The produced strip-shaped positive electrode plate and negative electrode plate were wound through a polyethylene separator having a width of 310 mm and a thickness of 40 μm so that these two electrode plates were not in direct contact with each other. At this time, the lead pieces 9 of the positive electrode plate and the negative electrode plate were respectively positioned on the opposite end surfaces of the wound group 6. The lengths of the positive electrode plate, the negative electrode plate, and the separator were adjusted so that the diameter of the wound group 6 was 65 ± 0.1 mm.
[0017]
The lead pieces 9 led out from the positive electrode plate are deformed, and all of them are gathered in the vicinity of the peripheral surface of the collar portion 7 integrally projecting from the periphery of the pole column (positive electrode external terminal 1) substantially on the extension line of the shaft core 11. After the contact, the lead piece 9 and the circumferential surface of the collar portion 7 were ultrasonically welded to connect and fix the lead piece 9 to the circumferential surface of the collar portion 7. The connection operation between the negative electrode external terminal 1 ′ and the lead piece 9 led out from the negative electrode plate was performed in the same manner as the connection operation between the positive electrode external terminal 1 and the lead piece 9 led out from the positive electrode plate.
[0018]
Thereafter, an insulating coating 8 was applied to the entire periphery of the collar 7 peripheral surface of the positive electrode external terminal 1 and the negative electrode external terminal 1 ′. This insulating coating 8 also exerted on the entire outer periphery of the wound group 6. For the insulating coating 8, an adhesive tape in which the base material was polyimide and an adhesive made of hexamethacrylate was applied on one side thereof was used. This adhesive tape was wound several times from the peripheral surface of the collar portion 7 to the outer peripheral surface of the wound group 6 to form an insulating coating 8. The number of turns is adjusted so that the maximum diameter portion of the wound group 6 becomes the insulating coating 8 existing portion, and the maximum diameter is slightly smaller than the inner diameter of the stainless steel battery container 5 so that the wound group 6 becomes the battery container 5. Inserted inside. The battery container 5 has an outer diameter of 67 mm and an inner diameter of 66 mm.
[0019]
Then, the second ceramic washer 3 ′ made of alumina and having a thickness of 2 mm, an inner diameter of 16 mm, and an outer diameter of 25 mm at the portion in contact with the back surface of the disc-shaped battery lid 4, the pole column constituting the positive electrode external terminal 1 at the tip, Each was fitted into a pole column constituting the negative electrode external terminal 1 ′. Further, a flat plate-like first ceramic washer 3 made of alumina and having a thickness of 2 mm, an inner diameter of 16 mm, and an outer diameter of 28 mm is placed on the battery lid 4, and the positive electrode external terminal 1 and the negative electrode external terminal 1 ′ are respectively connected to the first ceramic. Passed through washer 3. Thereafter, the peripheral end surface of the battery lid 4 was fitted into the opening of the battery container 5, and the entire contact portions were laser welded. At this time, the positive electrode external terminal 1 and the negative electrode external terminal 1 ′ protrude through the hole formed in the center of the battery lid 4 and project outside the battery lid 4. Then, the first ceramic washer 3 and the metal washer 14 smoother than the bottom surface of the metal nut 2 were fitted into the positive external terminal 1 and the negative external terminal 1 ′ in this order. The battery lid 4 is provided with a cleavage valve 10 as an internal pressure reduction mechanism that cleaves in response to an increase in the internal pressure of the battery. The cleavage pressure of the cleavage valve 10 is 1.3 × 10 ⁶ ~ 1.8 × 10 ⁶ Pa.
[0020]
Next, the nut 2 is screwed to the positive electrode external terminal 1 and the negative electrode external terminal 1 ′, and the battery lid 4 is connected to the flange portion 7 via the second ceramic washer 3 ′, the first ceramic washer 3, and the metal washer 14. The nut 2 was fixed by tightening. The tightening torque value at this time was about 7 N · m. Note that the metal washer 14 did not rotate until the tightening operation was completed. In this state, the power generation element inside the battery container 5 is blocked from the outside air by the compression of the rubber (EPDM) O-ring 16 interposed between the back surface of the battery lid 4 and the flange portion 7.
[0021]
Thereafter, a predetermined amount of non-aqueous electrolyte was injected into the battery container 5 from the injection port 15 provided in the battery lid 4, and then the injection port 15 was sealed to complete the cylindrical lithium ion battery 20.
[0022]
Non-aqueous electrolyte includes lithium hexafluorophosphate (LiPF) into a mixed solution of ethylene carbonate, dimethyl carbonate and diethyl carbonate in a volume ratio of 1: 1: 1. ₆ ) Was dissolved at 1 mol / liter. The cylindrical lithium ion battery 20 is not provided with a current interruption mechanism such as a PTC (Positive Temperature Coefficient) element that cuts off the current in response to an increase in the internal pressure of the battery container 5.
[0023]
【Example】
Next, examples of the cylindrical lithium ion battery 20 manufactured according to the present embodiment will be described. In addition, it describes together about the battery of the comparative example produced for the comparison.
[0024]
(Example 1)
As shown in Table 1 below, in Example 1, manganic acid having a primary particle diameter of about 1 to 2 μm, a secondary particle diameter of about 20 μm, and an atomic ratio of Li to Mn (Li / Mn ratio) of 0.52 as the positive electrode active material. Lithium (LiMn ₂ O ₄ ) The collector single-sided surface of the positive electrode active material mixture layer (active material coating portion) with a blending ratio of powder, scaly graphite having an average particle diameter of 18 μm, and polyvinylidene fluoride in weight percent of 90: 5: 5 The coating amount of lithium manganate per 270 g / m ² The thickness of the positive electrode active material mixture layer (active material application part) (not including the current collector thickness) was 226 μm, and the length of the positive electrode plate was 615 cm. LiMn ₂ O ₄ The average particle size of the flake graphite with respect to the secondary particle size is 0.9 times. On the other hand, for the negative electrode plate, MCMB, which is mesophase-based spherical graphite, is used as the negative electrode active material, and the thickness of the negative electrode active material mixture layer (active material application part) (not including the current collector thickness) is 150 μm. The length was 633 cm. In addition, the average particle diameter of scaly graphite can be adjusted by sieving.
[0025]
[Table 1]

[0026]
In addition, when the produced electrode plate is wound, the positive electrode plate does not protrude from the negative electrode plate in the winding direction on the innermost periphery of the winding, and the positive electrode plate protrudes from the negative electrode plate in the winding direction on the outermost periphery. To prevent this, the length of the negative electrode plate was set to be 18 cm longer than that of the positive electrode plate. In addition, the width of the negative electrode active material application part is 5 mm longer than the width of the positive electrode active material application part so that the positive electrode active material application part does not protrude from the negative electrode active material application part even in the winding direction and the vertical direction. (The same applies to the following examples and comparative examples.)
[0027]
(Example 2)
As shown in Table 1, in Example 2, the coating amount of lithium manganate was 300 g / m. ² The thickness of the positive electrode active material mixture layer (active material application portion) (current collector thickness is not included) is 252 μm, the length of the positive electrode plate is 565 cm, and the negative electrode active material mixture layer (active material application portion) ) (Not including the current collector thickness) was 166 μm, and the length of the negative electrode plate was 583 cm.
[0028]
(Examples 2-2 to 2-5)
As shown in Table 1, in Examples 2-2 to 2-5, the Li / Mn ratio of lithium manganate was set to 0.55, 0.58, 0.60, and 0.61, respectively. A battery was produced in the same manner as in Example 2.
[0029]
(Example 3)
As shown in Table 1, in Example 3, the coating amount of lithium manganate was 330 g / m. ² The thickness of the positive electrode active material mixture layer (active material application part) (not including the current collector thickness) is 277 μm, the length of the positive electrode plate is 523 cm, and the negative electrode active material mixture layer (active material application part) ) (Not including the current collector thickness) was 183 μm, and the length of the negative electrode plate was 541 cm, and a battery was fabricated in the same manner as in Example 1.
[0030]
(Example 4)
As shown in Table 1, in Example 4, the same lithium manganate powder as in Example 1 and flaky graphite (LiMn) having an average particle diameter of 18 μm ₂ O ₄ The ratio of the average particle size of the flake graphite to the secondary particle size of: 0.9 times the polyvinylidene fluoride was 90: 3: 7 by weight, and the positive electrode active material mixture layer (active material coating) Part) of the current collector is 300 g / m. ² The thickness of the positive electrode active material mixture layer (active material application part) (not including the current collector thickness) was 252 μm, and the length of the positive electrode plate was 565 cm. On the other hand, for the negative electrode plate, MCMB was used as the negative electrode active material, the thickness of the negative electrode active material mixture layer (active material application part) (not including the current collector thickness) was 166 μm, and the length was 583 cm. A battery was produced.
[0031]
(Example 5)
As shown in Table 1, in Example 5, the same lithium manganate powder as in Example 1 and flaky graphite (LiMn) having an average particle diameter of 18 μm ₂ O ₄ The ratio of the average particle size of the flake graphite to the secondary particle size of: 0.9 times the polyvinylidene fluoride was 90: 7: 3 by weight%, and the positive electrode active material mixture layer (active material coating) Part) of the current collector is 300 g / m. ² The thickness of the positive electrode active material mixture layer (active material application portion) (not including the current collector thickness) was 260 μm, and the length of the positive electrode plate was 556 cm. On the other hand, for the negative electrode plate, MCMB was used as the negative electrode active material, the thickness of the negative electrode active material mixture layer (active material application part) (not including the current collector thickness) was 166 μm, and the length was 574 cm. A battery was produced.
[0032]
(Example 6)
As shown in Table 1, in Example 6, the same lithium manganate powder as in Example 1 and flaky graphite (LiMn) having an average particle diameter of 18 μm ₂ O ₄ The average particle size of the flaky graphite with respect to the secondary particle size of: 0.9 times), the blending ratio of ketjen black (KB) and polyvinylidene fluoride is 90: 4: 1: 5 by weight%, The coating amount of lithium manganate per one side of the current collector of the positive electrode active material mixture layer (active material application part) is 300 g / m. ² The thickness of the positive electrode active material mixture layer (active material application part) (not including the current collector thickness) was 252 μm, and the length of the positive electrode plate was 565 cm. On the other hand, for the negative electrode plate, MCMB was used as the negative electrode active material, the thickness of the negative electrode active material mixture layer (active material application part) (not including the current collector thickness) was 166 μm, and the length was 583 cm. A battery was produced.
[0033]
(Example 7)
As shown in Table 1, in Example 7, the same lithium manganate powder as in Example 1 and flaky graphite (LiMn) having an average particle diameter of 2 μm ₂ O ₄ The average particle size of the flake graphite with respect to the secondary particle size of: 0.1 times), the blending ratio of ketjen black (KB) and polyvinylidene fluoride is 90: 4: 1: 5 by weight%, The coating amount of lithium manganate per one side of the current collector of the positive electrode active material mixture layer (active material application part) is 300 g / m. ² The thickness of the positive electrode active material mixture layer (active material application part) (not including the current collector thickness) was 252 μm, and the length of the positive electrode plate was 565 cm. On the other hand, for the negative electrode plate, MCMB was used as the negative electrode active material, the thickness of the negative electrode active material mixture layer (active material application part) (not including the current collector thickness) was 166 μm, and the length was 583 cm. A battery was produced.
[0034]
(Example 8)
As shown in Table 1, in Example 8, the same lithium manganate powder as in Example 1 and flaky graphite (LiMn) having an average particle diameter of 4 μm ₂ O ₄ The average particle size of the flake graphite with respect to the secondary particle size: 0.2 times), the blending ratio of ketjen black (KB) and polyvinylidene fluoride is 90: 4: 1: 5 by weight%, The coating amount of lithium manganate per one side of the current collector of the positive electrode active material mixture layer (active material application part) is 300 g / m. ² The thickness of the positive electrode active material mixture layer (active material application part) (not including the current collector thickness) was 252 μm, and the length of the positive electrode plate was 565 cm. On the other hand, for the negative electrode plate, MCMB was used as the negative electrode active material, the thickness of the negative electrode active material mixture layer (active material application part) (not including the current collector thickness) was 166 μm, and the length was 583 cm. A battery was produced.
[0035]
Example 9
As shown in Table 1, in Example 9, the same lithium manganate powder as in Example 1 and flaky graphite (LiMn) having an average particle diameter of 10 μm ₂ O ₄ The average particle size of the flake graphite with respect to the secondary particle size: 0.5 times), the blend ratio of ketjen black (KB) and polyvinylidene fluoride is 90: 4: 1: 5 by weight%, The coating amount of lithium manganate per one side of the current collector of the positive electrode active material mixture layer (active material application part) is 300 g / m. ² The positive electrode active material mixture layer (active material application part) had a thickness (not including the current collector thickness) of 252 μm and a length of 565 cm. On the other hand, for the negative electrode plate, MCMB was used as the negative electrode active material, the thickness of the negative electrode active material mixture layer (active material application part) (not including the current collector thickness) was 166 μm, and the length was 583 cm. A battery was produced.
[0036]
(Example 10)
As shown in Table 1, in Example 10, the same lithium manganate powder as in Example 1 and flaky graphite (LiMn) having an average particle diameter of 16 μm ₂ O ₄ The average particle size of the flake graphite with respect to the secondary particle size of: 0.8 times), the blending ratio of ketjen black (KB) and polyvinylidene fluoride is 90: 4: 1: 5 by weight%, The coating amount of lithium manganate per one side of the current collector of the positive electrode active material mixture layer (active material application part) is 300 g / m. ² The positive electrode active material mixture layer (active material application part) had a thickness (not including the current collector thickness) of 252 μm and a length of 565 cm. On the other hand, for the negative electrode plate, MCMB was used as the negative electrode active material, the thickness of the negative electrode active material mixture layer (active material application part) (not including the current collector thickness) was 166 μm, and the length was 583 cm. A battery was produced.
[0037]
(Example 11)
As shown in Table 1, in Example 11, the same lithium manganate powder as in Example 1 and flaky graphite (LiMn) having an average particle diameter of 10 μm ₂ O ₄ The average particle size of the flaky graphite with respect to the secondary particle size of: 0.5 times), the blending ratio of acetylene black (AB) and polyvinylidene fluoride was 90: 4: 1: 5 by weight%, and the positive electrode The coating amount of lithium manganate per one side of the current collector of the active material mixture layer (active material application part) is 300 g / m ² The positive electrode active material mixture layer (active material application part) had a thickness (not including the current collector thickness) of 252 μm and a length of 565 cm. On the other hand, for the negative electrode plate, MCMB was used as the negative electrode active material, the thickness of the negative electrode active material mixture layer (active material application part) (not including the current collector thickness) was 166 μm, and the length was 583 cm. A battery was produced.
[0038]
(Example 12)
As shown in Table 1, in Example 12, as the positive electrode active material, lithium manganate having a primary particle size of about 1 to 2 μm, a secondary particle size of about 20 μm, and an atomic ratio of Li to Mn (Li / Mn ratio) of 0.55. (LiMn ₂ O ₄ ) Powder and flake graphite (LiMn) with an average particle size of 10 μm ₂ O ₄ The average particle size of the flaky graphite with respect to the secondary particle size of: 0.5 times), the blending ratio of acetylene black (AB) and polyvinylidene fluoride was 90: 4: 1: 5 by weight%, and the positive electrode The coating amount of lithium manganate per one side of the current collector of the active material mixture layer (active material application part) is 300 g / m ² The positive electrode active material mixture layer (active material application part) had a thickness (not including the current collector thickness) of 252 μm and a length of 565 cm. On the other hand, for the negative electrode plate, MCMB was used as the negative electrode active material, the thickness of the negative electrode active material mixture layer (active material application part) (not including the current collector thickness) was 166 μm, and the length was 583 cm. A battery was produced.
[0039]
(Example 13)
As shown in Table 1, in Example 13, as the positive electrode active material, lithium manganate having a primary particle diameter of about 1 to 2 μm, a secondary particle diameter of about 20 μm, and an atomic ratio of Li to Mn (Li / Mn ratio) of 0.58. (LiMn ₂ O ₄ ) Powder and flake graphite (LiMn) with an average particle size of 10 μm ₂ O ₄ The average particle size of the flaky graphite with respect to the secondary particle size of: 0.5 times), the blending ratio of acetylene black (AB) and polyvinylidene fluoride was 90: 4: 1: 5 by weight%, and the positive electrode The coating amount of lithium manganate per one side of the current collector of the active material mixture layer (active material application part) is 300 g / m ² The positive electrode active material mixture layer (active material application part) had a thickness (not including the current collector thickness) of 252 μm and a length of 565 cm. On the other hand, for the negative electrode plate, MCMB was used as the negative electrode active material, the thickness of the negative electrode active material mixture layer (active material application part) (not including the current collector thickness) was 166 μm, and the length was 583 cm. A battery was produced.
[0040]
(Example 14)
As shown in Table 1, in Example 14, lithium manganate having a primary particle size of about 1 to 2 μm, a secondary particle size of about 20 μm, and an atomic ratio of Li to Mn (Li / Mn ratio) of 0.60 as the positive electrode active material. (LiMn ₂ O ₄ ) Powder and flake graphite (LiMn) with an average particle size of 10 μm ₂ O ₄ The average particle size of the flaky graphite with respect to the secondary particle size of: 0.5 times), the blending ratio of acetylene black (AB) and polyvinylidene fluoride was 90: 4: 1: 5 by weight%, and the positive electrode The coating amount of lithium manganate per one side of the current collector of the active material mixture layer (active material application part) is 300 g / m ² The positive electrode active material mixture layer (active material application part) had a thickness (not including the current collector thickness) of 252 μm and a length of 565 cm. On the other hand, for the negative electrode plate, MCMB was used as the negative electrode active material, the thickness of the negative electrode active material mixture layer (active material application part) (not including the current collector thickness) was 166 μm, and the length was 583 cm. A battery was produced.
[0041]
(Example 15)
As shown in Table 1, in Example 15, lithium manganate having a primary particle size of about 1 to 2 μm, a secondary particle size of about 20 μm, and an atomic ratio of Li to Mn (Li / Mn ratio) of 0.61 as the positive electrode active material. (LiMn ₂ O ₄ ) Powder and flake graphite (LiMn) with an average particle size of 10 μm ₂ O ₄ The average particle size of the flaky graphite with respect to the secondary particle size of: 0.5 times), the blending ratio of acetylene black (AB) and polyvinylidene fluoride was 90: 4: 1: 5 by weight%, and the positive electrode The coating amount of lithium manganate per one side of the current collector of the active material mixture layer (active material application part) is 300 g / m ² The positive electrode active material mixture layer (active material application part) had a thickness (not including the current collector thickness) of 252 μm and a length of 565 cm. On the other hand, for the negative electrode plate, MCMB was used as the negative electrode active material, the thickness of the negative electrode active material mixture layer (active material application part) (not including the current collector thickness) was 166 μm, and the length was 583 cm. A battery was produced.
[0042]
(Example 16)
As shown in Table 1, in Example 16, the same lithium manganate powder as in Example 1 and flaky graphite (LiMn) having an average particle diameter of 10 μm ₂ O ₄ The average particle size of the flaky graphite with respect to the secondary particle size of: 0.5 times), the blending ratio of acetylene black (AB) and polyvinylidene fluoride was 90: 4: 1: 5 by weight%, and the positive electrode The coating amount of lithium manganate per one side of the current collector of the active material mixture layer (active material application part) is 300 g / m ² The positive electrode active material mixture layer (active material application part) had a thickness (not including the current collector thickness) of 252 μm and a length of 605 cm. On the other hand, for the negative electrode plate, amorphous carbon is used as the negative electrode active material, the thickness of the negative electrode active material mixture layer (active material application part) (not including the current collector thickness) is 133 μm, and the length is A battery was manufactured at 623 cm.
[0043]
(Examples 16-2 to 16-5)
As shown in Table 1, in Examples 16-2 to 16-5, the Li / Mn ratio of lithium manganate was changed to 0.55, 0.58, 0.60, and 0.61, respectively. A battery was produced in the same manner as in Example 16.
[0044]
(Example 17)
As shown in Table 1, in Example 17, the same lithium manganate powder as in Example 1 and flaky graphite (LiMn) having an average particle diameter of 10 μm ₂ O ₄ The ratio of the average particle size of the flake graphite to the secondary particle size of the graphite is 0.5: 5 and the blending ratio of polyvinylidene fluoride is 90: 5: 5 by weight%, and the positive electrode active material mixture layer (active material coating) Part) of the current collector is 300 g / m. ² The positive electrode active material mixture layer (active material application part) had a thickness (not including the current collector thickness) of 252 μm and a length of 605 cm. On the other hand, for the negative electrode plate, amorphous carbon is used as the negative electrode active material, the thickness of the negative electrode active material mixture layer (active material application part) (not including the current collector thickness) is 133 μm, and the length is A battery was manufactured at 623 cm.
[0045]
(Examples 17-2 to 17-5)
As shown in Table 1, in Examples 17-2 to 17-5, the Li / Mn ratio of lithium manganate was changed to 0.55, 0.58, 0.60, and 0.61, respectively. A battery was produced in the same manner as in Example 17.
[0046]
(Comparative Example 1)
As shown in Table 1, in Comparative Example 1, the coating amount of lithium manganate was 260 g / m. ² The thickness of the positive electrode active material mixture layer (active material application portion) (current collector thickness is not included) is 218 μm, the length is 633 cm, and the negative electrode active material mixture layer (active material application portion) A battery was prepared in the same manner as in Example 1 except that the thickness (excluding the current collector thickness) was 144 μm and the length of the negative electrode plate was 651 cm.
[0047]
(Comparative Example 2)
As shown in Table 1, in Comparative Example 2, the coating amount of lithium manganate was 340 g / m. ² The thickness of the positive electrode active material mixture layer (active material application portion) (current collector thickness is not included) is 285 μm, the length is 511 cm, and the negative electrode active material mixture layer (active material application portion) A battery was prepared in the same manner as in Example 1 except that the thickness (not including the current collector thickness) was 189 μm and the length of the negative electrode plate was 529 cm.
[0048]
(Comparative Example 3)
As shown in Table 1, in Comparative Example 3, the same lithium manganate powder as in Example 1 and flaky graphite (LiMn) having an average particle diameter of 18 μm ₂ O ₄ The ratio of the average particle size of the flake graphite to the secondary particle size of: 0.9 times the polyvinylidene fluoride was 91: 2: 7 by weight%, and the positive electrode active material mixture layer (active material coating) Part) of the current collector is 300 g / m. ² The positive electrode active material mixture layer (active material application portion) has a thickness (not including the current collector thickness) of 249 μm, the positive electrode plate has a length of 568 cm, and MCMB is used as the negative electrode active material. A battery was fabricated with a mixture layer (active material application part) thickness (not including current collector thickness) of 166 μm and a negative electrode plate length of 586 cm.
[0049]
(Comparative Example 4)
As shown in Table 1, in Comparative Example 4, the same lithium manganate powder as in Example 1 and flaky graphite (LiMn) having an average particle diameter of 18 μm ₂ O ₄ The ratio of the average particle size of the flake graphite to the secondary particle size of: 0.9 times and the blend ratio of polyvinylidene fluoride is 86: 8: 6 by weight%, and the positive electrode active material mixture layer (active material coating) Part) of the current collector is 300 g / m. ² The thickness of the positive electrode active material mixture layer (active material application part) (not including the current collector thickness) was 263 μm, and the length of the positive electrode plate was 553 cm. On the other hand, for the negative electrode plate, MCMB was used as the negative electrode active material, the thickness of the negative electrode active material mixture layer (active material application part) (not including the current collector thickness) was 166 μm, and the length of the negative electrode plate was A battery was manufactured at 571 cm.
[0050]
<Test and evaluation>
Next, the following series of tests were performed on the batteries of Examples and Comparative Examples manufactured as described above.
[0051]
Each battery of the examples and comparative examples was charged and then discharged, and the discharge capacity was measured. The charging conditions were a 4.2 V constant voltage, a limiting current of 80 A, and 3.5 hours. The discharge conditions were a 20 A constant current and a final voltage of 2.7 V.
[0052]
Further, the discharge output of the charged battery was measured under the above conditions. Measurement conditions are 20A, 40A, and 80A. The voltage at 5 seconds is read for each discharge current, plotted on the vertical axis against the horizontal axis current value, and the approximate straight line connecting the three points intersects with 2.7V. The product of the current value of 2.7 and 2.7 V was used as the output.
[0053]
Furthermore, each battery of the example and the comparative example was charged and discharged 100 times under the above conditions, and then the output (capacity) was measured. Naturally, the higher the maintenance ratio, the better the life characteristics.
[0054]
These measurements of charge, discharge, and output were all performed in an atmosphere having an environmental temperature of 25 ± 1 ° C.
[0055]
Thereafter, the produced battery was continuously charged at a constant current of 80 A at room temperature, and the behavior of the battery was observed. The results are shown in Table 2 below. The phenomenon is that gas release consisting of volatiles of electrolyte occurs after cleavage valve cleavage. In order to compare the degree of gas release, the battery surface temperature immediately after the occurrence of the phenomenon was measured. Further, after the gas was released, the battery container was checked for deformation. In Table 2, “◯” indicates that no deformation of the battery container was observed, “Δ” indicates that the battery container was slightly deformed, and “×” indicates that the battery container was greatly deformed. Show.
[0056]
[Table 2]

[0057]
As shown in Table 2, in the batteries of Examples 1 to 5, high-capacity and high-power batteries were obtained, and the battery behavior during continuous charging was gentle. The surface temperature of the battery at this time was 140 ° C. to 210 ° C. On the other hand, the coating amount of lithium manganate is 270 g / m. ² Although the battery of Comparative Example 1 having a lower temperature than the above yields a battery with a high capacity and a high output, the battery behavior during continuous charging becomes intense with deformation of the battery, and the battery surface temperature exceeds 300 ° C. It was. Conversely, the coating amount of lithium manganate is 330 g / m. ² The battery of Comparative Example 2, which exceeded the above, had a gentle battery behavior during continuous charging, but was accompanied by a decrease in output, and was not suitable as a battery for electric vehicles. Similarly, in the battery of Comparative Example 3, the amount of graphite of the positive electrode conductive material was less than 3% by weight, resulting in a decrease in output. On the other hand, in the battery of Comparative Example 4 in which the amount of graphite of the positive electrode conductive material exceeds 7% by weight, a battery with high capacity and high output can be obtained, but the battery behavior during continuous charging was accompanied by deformation of the battery. As a result, the battery surface temperature was 300 ° C.
[0058]
In the batteries of Examples 6 to 16-5 in which graphite and amorphous carbon were mixed in the positive electrode conductive material, a battery with high output could be obtained. In the batteries of Examples 6 to 10 using ketjen black as amorphous carbon, the ratio of the particle diameter of the conductive graphite to the secondary particle diameter of lithium manganate as the positive electrode active material was 0.2 to 0.00. The batteries of Examples 8 to 10 which are 8, in particular, have higher output. In the battery of Example 7 in which the ratio of the particle diameter of the conductive material graphite to the secondary particle diameter of lithium manganate is less than 0.2, the battery surface temperature during continuous charging was 200 ° C., and Examples 8 to It is slightly higher than 10 batteries.
[0059]
In the batteries of Examples 11 to 16-5 using acetylene black for amorphous carbon, a higher output was obtained and the output retention rate after 100 times of charge / discharge was also high.
[0060]
Example 12 to Example 14, Example 2-2 to Example 2-4, Example 16-2 to Example 16-4, Example in which Li / Mn ratio of lithium manganate is 0.55 or more The batteries of 17-2 to Example 17-4 have an extremely high output retention rate. However, in the batteries of Example 15, Example 2-5, Example 16-5, and Example 17-5 in which the Li / Mn ratio of lithium manganate exceeds 0.60, the result is accompanied by a decrease in capacity. It can be seen that the / Mn ratio is preferably in the range of 0.55 to 0.60.
[0061]
The batteries of Example 16, Example 16-2 to Example 16-5, Example 17, and Example 17-2 to Example 17-5 using amorphous carbon for the negative electrode plate had extremely high output power and An extremely high output retention rate and the lowest battery surface temperature during continuous charging were obtained. Therefore, the batteries of Examples 16, 16-2 to 16-5, 17, 17-2 to 17-5 are high-capacity, high-output, and excellent in safety, and are well-balanced. It can be said.
[0062]
As described above, the cylindrical lithium ion battery 20 of the present embodiment is a battery that exhibits extremely gentle behavior when the battery is exposed to an abnormal state and is excellent in safety. Thus, a battery with high capacity, high output, and extremely high safety is particularly suitable for a power source of an electric vehicle.
[0063]
In this embodiment, the large secondary battery used for the power source for the electric vehicle is exemplified, but the present invention is not limited to the size and the battery capacity of the battery, and the battery capacity is about 20 Ah. It has been confirmed that the invention exerts remarkable effects. In the present embodiment, the cylindrical battery is exemplified, but the present invention is not limited to the shape of the battery, and can be applied to a rectangular battery or other polygonal batteries. Further, as a shape applicable to the present invention, as described above, the battery may be other than a battery in which the positive and negative external terminals penetrate the battery lid and the positive and negative external terminals are pressed through the shaft core in the battery container. I do not care. As an example of such a structure, a battery having a structure in which a battery upper lid is sealed by caulking in a bottomed cylindrical container (can) can be exemplified.
[0064]
Moreover, in this embodiment, although the base material is a polyimide and the example which used the adhesive tape which apply | coated the adhesive which consists of hexamethacrylate to the one side was shown for insulation coating, for example, a base material is polypropylene, polyethylene, etc. In particular, an adhesive tape in which an acrylic adhesive such as hexamethacrylate or butyl acrylate is applied to one or both surfaces thereof, a tape made of polyolefin or polyimide to which no adhesive is applied, and the like can be suitably used.
[0065]
Furthermore, in this embodiment, lithium manganate is used as the positive electrode for the lithium ion battery, amorphous carbon is used as the negative electrode, and a mixed solution of ethylene carbonate, dimethyl carbonate, and diethyl carbonate in a volume ratio of 1: 1: 1 is used as the electrolytic solution. A solution obtained by dissolving 1 mol / liter of lithium fluorophosphate was used, but the battery of the present invention is not particularly limited, and any of the conductive materials and binders that are usually used can be used. is there. In general, lithium manganate can be synthesized by mixing and baking an appropriate lithium salt and manganese oxide, but the desired Li / Mn ratio can be adjusted by controlling the charging ratio of the lithium salt and manganese oxide. can do.
[0066]
Moreover, as an electrode plate active material binder for lithium ion batteries that can be used in other than this embodiment, Polytetrafluoroethylene , Polyethylene, polystyrene, polybutadiene, butyl rubber, nitrile rubber, styrene / butadiene rubber, polysulfide rubber, nitrocellulose, cyanoethyl cellulose, various latexes, acrylonitrile, vinyl fluoride, vinylidene fluoride, propylene fluoride, chloroprene fluoride, etc. There are coalescence and a mixture thereof.
[0067]
Further, as the positive electrode active material for lithium ion batteries that can be used in other embodiments, lithium is a material capable of inserting / extracting lithium, and lithium manganese complex oxide in which a sufficient amount of lithium is inserted in advance is preferable. Alternatively, lithium manganate having a spinel structure, or a material obtained by substituting or doping a part of manganese or lithium in a crystal with an element other than those may be used.
[0068]
Furthermore, the negative electrode active material for lithium ion batteries that can be used other than in the present embodiment is not particularly limited other than the matters described in the claims. For example, natural graphite, various artificial graphite materials, carbonaceous materials such as coke, amorphous carbon, etc. may be used, and the particle shape is not particularly limited, such as scaly, spherical, fibrous, massive, etc. Absent.
[0069]
As the nonaqueous electrolytic solution, an electrolytic solution in which a general lithium salt is used as an electrolyte and this is dissolved in an organic solvent is used. However, the lithium salt and organic solvent used are not particularly limited. For example, as an electrolyte, LiClO _Four , LiAsF ₆ , LiPF ₆ , LiBF _Four , LiB (C ₆ H _Five ) _Four , CH _Three SO _Three Li, CF _Three SO _Three Li or the like or a mixture thereof can be used. Nonaqueous electrolyte organic solvents include propylene carbonate, ethylene carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, γ-butyrolactone, tetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3- Dioxolane, diethyl ether, sulfolane, methyl sulfolane, acetonitrile, propiontonyl, or a mixed solvent of two or more of these may be used, and the mixing ratio is not limited.
[0070]
【The invention's effect】
As described above, according to the present invention, the secondary particles are formed of an aggregate of primary particles having an average particle diameter of 0.1 μm to 2 μm. Spinel Lithium manganese complex oxide and Of a mixture of graphite and amorphous carbon Using a positive electrode in which an active material mixture containing a conductive material is applied to both sides of a strip-shaped current collector in an approximately equal amount and a negative electrode capable of inserting and extracting lithium ions by charging and discharging The average particle size of graphite is 0.2 to 0.8 times the average particle size of secondary particles. Therefore, high capacity and high output can be achieved, and the coating amount of lithium manganese complex oxide on one side of the current collector is 270 g / m. ² ~ 330g / m ² In addition, since the amount of the conductive material is set to 3 to 7% by weight, the gas release from the internal pressure release mechanism is performed very gently. The effect that a water electrolyte secondary battery is realizable can be acquired.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a cylindrical lithium ion battery according to an embodiment to which the present invention is applicable.
[Explanation of symbols]
1 Positive external terminal
1 'Negative external terminal
2 nuts
3 First ceramic washer
3 'second ceramic washer
4 Battery cover (part of battery container)
5 Battery container
6 Winding group (electrode winding group)
7 Buttocks
8 Insulation coating
9 Lead piece
10 Cleavage valve (Internal pressure reduction mechanism)
20 Cylindrical lithium ion battery (non-aqueous electrolyte secondary battery)

Claims (4)

A positive electrode active material composition comprising a spinel-based lithium manganese complex oxide composed of secondary particles formed of an aggregate of primary particles having an average particle diameter of 0.1 μm to 2 μm, and a conductive material of a mixture of graphite and amorphous carbon. An electrode winding group in which a positive electrode in which an agent is applied on both surfaces of a strip-shaped current collector and a negative electrode capable of occluding and releasing lithium ions by charging and discharging is wound through a separator at a predetermined pressure. In a non-aqueous electrolyte secondary battery housed in a battery container having an internal pressure release mechanism for releasing internal pressure, a coating amount of the lithium manganese complex oxide per one surface of the current collector is 270 g / m ^{2 to} 330 g / m. ^2, before Symbol positive electrode active conducting material amount contained in the material mixture is 3% to 7 wt% der is, and the average particle diameter of the graphite, 0 of the average particle diameter of the secondary particles .2-fold to a non-aqueous, wherein 0.8 Baidea Rukoto Solution solution secondary battery. The non-aqueous electrolyte secondary battery according to claim 1 , wherein the amorphous carbon is acetylene black. The non-aqueous electrolyte secondary battery according to claim 1 or 2 , wherein a Li / Mn ratio of the lithium manganese complex oxide is 0.55 to 0.60. The non-aqueous electrolyte secondary battery according to any one of claims 1 to 3 , wherein the negative electrode active material is amorphous carbon.

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