Sanyo Electric Co., Ltd.

Panasonic Corporation

Shouichiro Sawa

Taizou Sunano

Atsushi Fukui

Ayano Toyoda

Maruo Kamino

Kazuto Fukuda

Yasunori Watanabe

A negative electrode including a current collector, a first mix layer containing first active material particles and a binder, and a second mix layer containing second active material particles and a binder. The first mix layer is placed on the current collector. The second mix layer overlies the first mix layer. The first active material particles and the second active material particles contain Si. The second mix layer includes a plurality of pillar portions. The expansion coefficient of the second mix layer during charge is higher than the expansion coefficient of the first mix layer during charge. The electrical conductivity of the first mix layer is higher than the electrical conductivity of the second mix layer.

Negative electrode for nonaqueous electrolyte secondary batteries

A negative electrode for a nonaqueous electrolyte secondary battery according to one aspect of the present invention includes a negative electrode mixture layer that contains a binder and a negative electrode active material particle that forms an alloy with lithium and is formed on a current collector. The negative electrode mixture layer includes a base portion near the current collector and pillar-shaped portions formed on the base portion. A negative electrode for a nonaqueous electrolyte secondary battery according to another aspect of the present invention includes a negative electrode mixture layer that contains a binder and a negative electrode active material particle that forms an alloy with lithium and is formed on a current collector. The negative electrode mixture layer includes pillar-shaped portions and the particle diameter of the negative electrode active material particle is 20% or less of the maximum diameter of the pillar-shaped portions.

Negative electrode for nonaqueous electrolyte secondary battery and nonaqueous electrolyte secondary battery

There are provided a negative electrode for a nonaqueous electrolyte secondary battery having excellent initial efficiency and good moldability of pillar portions included in a negative electrode mixture layer, and a nonaqueous electrolyte secondary battery. A negative electrode () for a nonaqueous electrolyte secondary battery according to one aspect of the present invention includes a negative electrode current collector () and a negative electrode mixture layer () formed on the negative electrode current collector () and containing a binder and a negative electrode active material particle that forms an alloy with lithium. The negative electrode mixture layer () includes a base portion () near the negative electrode current collector () and pillar portions () formed on the base portion (). The binder contains a polyimide resin. The polyimide resin has an average molecular weight of 60000 or more.

A lithium secondary battery with superior cycle performance is provided. The lithium secondary battery includes a negative electrode including a negative electrode active material layer disposed on a negative electrode current collector and containing negative electrode active material particles, negative electrode conductor particles, and a negative electrode binder; a positive electrode containing a positive electrode active material; and a non-aqueous electrolyte. The concentration of the negative electrode conductor particles in a surface layer of the negative electrode active material layer facing away from the negative electrode current collector is higher than the concentration of the negative electrode conductor particles in a center of the negative electrode active material layer.

Lithium secondary battery and method for manufacturing the same

A lithium secondary battery and a method for producing the lithium secondary battery. The lithium secondary battery includes a negative electrodein which negative electrode mixture layersandthat contain active material particles containing silicon and/or a silicon alloy and a binder are disposed on the surfaces of a current collector. A electrode body is formed by spirally winding, from inside to outside, a laminate body; and in an outer end portion of the negative electrode, the negative electrode mixture layersandhave tapering portionsandwhose thicknesses decrease toward endsandof the negative electrode mixture layersand; and oozing portionsandmainly containing the binder are formed at the tips of the tapering portionsandof the negative electrode mixture layersand

Lithium secondary battery and method for producing the same

A lithium secondary battery has a wound electrode assembly (). The wound electrode assembly () has a negative electrode () having a negative electrode active material layer containing a negative electrode active material capable of alloying with lithium and having a filling density of 2.0 g/cc or less, a positive electrode () having a positive electrode active material layer containing a positive electrode active material made of a transition metal composite oxide, a separator () disposed between the positive and negative electrodes and having a penetration resistance of 500 g or greater, and a cylindrical hollow space () at a winding axis and in the vicinity thereof, wherein the positive electrode (), the negative electrode (), and the separator () are spirally wound. A columnar center pin () having a diameter of from 75% to 95% of the diameter of the hollow space is disposed in the hollow space.

Growing community of inventors

Tokushima, Japan

Shouichiro Sawa