Nisshin Steel Co., Ltd.

Takao Tsujimura

Atsushi Komatsu

Atsushi Andoh

Takeshi Shimizu

Takahiro Fujii

Toshiharu Kittaka

Kouichi Watanabe

Yoshikazu Morita

Norihiro Kon

Sho Majima

Nobuhiko Yamaki

Yoshie Yoshida

Shigeyasu Morikawa

Atsushi Steel & Tech Dev Lab Andoh

A negative electrode collector using a copper-covered steel foil for carrying a negative electrode active material for lithium ion secondary batteries has a steel sheet as the core material thereof and has, on both surfaces thereof, a copper covering layer having a mean thickness tof from 0.02 to 5.0 &#x3bc;m on each surface, and of which the total mean thickness, t, including the copper covering layeris from 3 to 100 &#x3bc;m with t/t of at most 0.3. The steel sheet can be common steel, austenitic stainless steel, or ferritic stainless steel. The copper covering layer can be a copper electroplating layer (including one rolled after plating). On the surface of the copper covering layer, for example, a carbon-based active material layer that has been densified through strong roll pressing is formed, and the copper-covered steel foil and the carbon-based active material layer constitute the negative electrode collector.

Copper-covered steel foil, negative electrode, and battery

[Problem] To provide a negative electrode collector for lithium ion secondary batteries, having a high strength and a large discharge capacity. [Means for Resolution] A negative electrode collector using a copper-covered steel foilfor carrying a negative electrode active material for lithium ion secondary batteries, which has a steel sheetas the core material thereof and has, on both surfaces thereof, a copper covering layerhaving a mean thickness tof from 0.02 to 5.0 &#x3bc;m on each surface, and of which the total mean thickness, t, including the copper covering layeris from 3 to 100 &#x3bc;m with t/t of at most 0.3. To the steel sheet, for example, applicable is common steel, austenitic stainless steel or ferritic stainless steel. The copper covering layeris, for example, a copper electroplating layer (including one rolled after plating). On the surface of the copper covering layer, for example, a carbon-based active material layer that has been densified through strong roll pressing is formed, and the copper-covered steel foiland the carbon-based active material layer constitute the negative electrode collector.

Method of making negative electrode

Degradation of the surface luster of a hot-dip Zn&mdash;Al&mdash;Mg plated steel sheet is inhibited by controlling the contact temperature between the plating layer and a water stream in a water cooling step after plating layer solidification, thereby suitably controlling the strip temperature during contact with the water stream, and further by incorporating a small amount of a suitable readily oxidizing element in the plating bath to stabilize the oxidation state of the plating surface layer Al and Mg.

Hot-dip Zn plated steel sheet excellent in luster-retaining property and method of producing the same

A hot-dip Zn&mdash;Al&mdash;Mg plated steel sheet good in corrosion resistance and surface appearance that is a hot-dip Zn-base plated steel sheet obtained by forming on a surface of a steel sheet a hot-dip Zn&mdash;Al&mdash;Mg plating layer composed of Al: 4.0-10 wt. %, Mg: 1.0-4.0 wt. % and the balance of Zn and unavoidable impurities, the plating layer having a metallic structure including a primary crystal Al phase or a primary crystal Al phase and a Zn single phase in a matrix of Al/Zn/Zn Mg ternary eutectic structure. To obtain a plating layer possessing this metallic structure, the cooling rate of the plating layer adhering to a steel strip extracted from a plating bath and the plating bath temperature are appropriately controlled in a continuous hot-dip plating machine and/or appropriate amounts of Ti and B are added to the bath. Occurrence of a stripe pattern peculiar to this plated steel sheet is controlled by morphology control of a Mg-containing oxide film up to solidification of the plating layer or by adding an appropriate amount of Be to the plating bath.

Hot-dip Zn-A1-Mg plated steel sheet good in corrosion resistance and surface appearance and method of producing the same

A hot-dip Zn&mdash;Al&mdash;Mg plated steel sheet good in corrosion resistance and surface appearance that is a hot-dip Zn-base plated steel sheet obtained by forming on a surface of a steel sheet a hot-dip Zn&mdash;Al&mdash;Mg plating layer composed of Al: 4.0-10 wt. %, Mg: 1.0-4.0 wt. % and the balance of Zn and unavoidable impurities, the plating layer having a metallic structure including a primary crystal Al phase or a primary crystal Al phase and a Zn single phase in a matrix of Al/Zn/Zn,Mg ternary eutectic structure. To obtain a plating layer possessing this metallic structure, the cooling rate of the plating layer adhering to a steel strip extracted from a plating bath and the plating bath temperature are appropriately controlled in a continuous hot-dip plating machine and/or appropriate amounts of Ti and B are added to the bath. Occurrence of a stripe pattern peculiar to this plated steel sheet is controlled by morphology control of a Mg-containing oxide film up to solidification of the plating layer or by adding an appropriate amount of Be to the plating bath.

Hot-dip Zn-Al-Mg coated steel sheet excellent in corrosion resistance and surface appearance and process for the production thereof

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Osaka, Japan

Takao Tsujimura