Panasonic Corporation

Panasonic Intellectual Property Management Co., Ltd.

Sanyo Electric Co., Ltd.

Tatsuki Hiraoka

Masaya Ugaji

Kazuya Iwamoto

Hideharu Takezawa

Taisuke Yamamoto

Katsumi Kashiwagi

Kei Kobayashi

Masahiro Shiraga

Yasutaka Kogetsu

Yoshiyuki Muraoka

Taizou Sunano

Yuki Suehiro

Kunihiko Mineya

Takuhiro Nishimura

It is an object to improve the initial charge-discharge efficiency of a nonaqueous electrolyte secondary battery that uses, as negative electrode active materials, a carbon material and a metal or metal oxide that forms an alloy with lithium. There is provided a nonaqueous electrolyte secondary battery including a positive electrode, a nonaqueous electrolyte, and a negative electrode which includes, as negative electrode active materials, a carbon material and a metal or metal oxide that forms an alloy with lithium and in which at least part of a surface of the carbon material is coated with a polymer material that does not react with lithium. The mass percentage of the polymer material that does not react with lithium relative to the carbon material is preferably 0.5 to 2 mass %.

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

Provided is a negative electrode for a non-aqueous electrolyte secondary battery, capable of improving the energy density and the cycle characteristics of the battery without lowering the initial charge/discharge efficiency of the battery. This negative electrode includes a negative electrode active material including a silicon oxide represented by SiOand carbon material. A proportion of a mass of the silicon oxide relative to a total mass of the silicon oxide and the carbon material: y satisfies 0.03&#x2264;y&#x2264;0.3. A difference between a theoretical capacity density of the negative electrode active material and a charge capacity density of the negative electrode active material when a cutoff voltage is 5 mV relative to lithium metal: &#x394;C (mAhg) satisfies L=&#x394;C/100 and 6y&#x2264;L&#x2264;12y+0.2.

Negative electrode for nonaqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery using the same

The initial charge/discharge efficiency and cycle characteristics of a nonaqueous electrolyte secondary battery are improved. Provided is a nonaqueous electrolyte secondary battery including a positive electrode, a negative electrode, a porous layer placed on the negative electrode, a separator, and a nonaqueous electrolyte. The porous layer has flat voids. The minor axis direction of each flat void is perpendicular to the plane direction of the porous layer and the major axis direction of the flat void is parallel to the plane direction of the porous layer. The ratio of the major axis to the minor axis of the flat void preferably ranges from 1.4 to 2.2.

Nonaqueous electrolyte secondary battery

Disclosed is a lithium ion secondary battery including: a positive electrode including a positive electrode active material layer comprising a positive electrode active material capable of absorbing and releasing lithium ions, and a positive electrode current collector; a negative electrode including a negative electrode active material layer comprising an alloy-formable active material, and a negative electrode current collector; a separator interposed between the positive electrode and the negative electrode; and a non-aqueous electrolyte. The positive electrode active material layer has an easily swellable resin having a degree of swelling with the non-aqueous electrolyte of 20% or more, and the negative electrode active material layer has a hardly swellable resin having a degree of swelling with the non-aqueous electrolyte of less than 20%.

Lithium ion secondary battery

A positive electrode plate, a separator, and a negative electrode plateare prepared. The positive electrode plate, the separator, and the negative electrode plateare combined so as to form a spirally-wound electrode assembly. A winding end portionof the electrode assemblyis fixed with a heat-sensitive adhesive (preferably, a heat-sensitive adhesive tape) whose adhesive force can be reduced by heating or cooling. The electrode assemblyis placed in an outer casing, and then the ambient temperature of the electrode assemblyis adjusted so that the electrode assemblyis loosened due to reduction in the adhesive force of the heat-sensitive adhesive. An electrolyte solution is injected into the outer casing

Method for producing lithium-ion battery

In a charging method for a non-aqueous electrolyte secondary battery which includes a positive electrode including a lithium-containing composite oxide as an active material, a negative electrode including an alloy-formable negative electrode active material, and a non-aqueous electrolyte, a voltage of the secondary battery is detected. When the detected value is smaller than a predetermined voltage x, charging is performed at a comparatively small current value B. When the detected value is equal to or greater than the predetermined voltage x and smaller than a predetermined voltage z, charging is performed at a comparatively great current value A. When the detected value is equal to or greater than the predetermined voltage z and smaller than a predetermined voltage y, charging is performed at a comparatively small current value C. When the detected value is greater than the predetermined voltage y, constant-voltage charging is performed or charging is terminated. Here, x&#x3c;z&#x3c;y.

Charging method and charger for non-aqueous electrolyte secondary battery

A current collector includes a substrate, a plurality of projections formed on a first portion of the substrate, and at least two adjacent minute projections formed on a second portion of the substrate. The substrate is a metal sheet. The first and second portions are formed on the surface of the substrate. The second portion includes 2 to 100 of minute projections. The minute projections have a height of below 35% of the average height of the plurality of projections. By forming an electrode active material layer on the face of the current collector where the plurality of projections are formed to make an electrode, the detachment of the electrode active material layer, and the spread of the detachment are significantly curbed.

Growing community of inventors

Hyogo, Japan

Tatsuki Hiraoka