Panasonic Corporation

Matsushita Electric Industrial Co., Ltd.

Panasonic Intellectual Property Management Co., Ltd.

Takaya Saito

Yasutaka Kogetsu

Takashi Takeuchi

Hidekazu Hiratsuka

Yoshiyuki Ozaki

Kohei Suzuki

Akihiro Taniguchi

Takayuki Shirane

Shuji Tsutsumi

Kozo Watanabe

Mitsuhiro Takeno

To improve high temperature storage characteristic of a non-aqueous electrolyte secondary battery suitable for high input/output application, the structure of a positive electrode active material is optimized. The non-aqueous electrolyte secondary battery includes a positive electrode; a negative electrode; a separator interposed between the positive and negative electrodes; and a non-aqueous electrolyte. The positive electrode active material includes secondary particles, each formed of an aggregate of primary particles. A value (V) defined by the formula: V=(1&#x2212;C/D)/(A&#xd7;B) is not less than 0.0005 and not greater than 0.04, where an average particle size of the primary particles is A &#x3bc;m, an average particle size of the positive electrode active material is B &#x3bc;m, a tap density of the positive electrode active material is C g/ml, and a true specific gravity of the positive electrode active material is D g/ml.

Non-aqueous electrolyte secondary battery

Disclosed is a non-aqueous electrolyte secondary battery comprising a positive electrode containing a nickel-containing lithium composite oxide, a negative electrode containing graphite, and a non-aqueous electrolyte. The cut-off voltage of charge of this non-aqueous electrolyte secondary battery is 4.25 to 4.6 V. The negative electrode contains an additive that reacts with lithium at a potential higher than the potential of graphite. The ratio A/B of a positive electrode capacity A based on the weight of the nickel-containing lithium composite oxide and the cut-off voltage of charge relative to a weight B of the graphite contained in a portion of a negative electrode material mixture layer opposing to a positive electrode material mixture layer is 300 to 340 mAh/g, and the irreversible capacity C of the positive electrode and the irreversible capacity D of the negative electrode in the portion opposing to the positive electrode satisfies C&#x2267;D.

Non-aqueous electrolyte secondary battery with high capacity and good life characteristics

Disclosed is a non-aqueous electrolyte secondary battery having an electrode group in which a positive electrode and a negative electrode are spirally wound with a separator interposed therebetween. The positive electrode contains a positive electrode active material and a binder. The positive electrode active material contains a mixture of two different particulate substances having different average particle sizes. The two different particulate substances are lithium composite metal oxides containing nickel as an essential element. The binder includes fluorocarbon resin and rubber particles. The fluorocarbon resin contains at least a vinylidene fluoride unit. The amount of the rubber particles per 100 parts by weight of the fluorocarbon resin is 1 to 25 parts by weight.

A positive electrode active material for a non-aqueous electrolyte secondary battery of this invention includes: a lithium nickel composite oxide containing lithium, nickel, and at least one metal element other than lithium and nickel; and a layer containing lithium carbonate, aluminum hydroxide, and aluminum oxide, the layer being carried on the surface of the lithium nickel composite oxide. The lithium nickel composite oxide is composed such that the ratio of the nickel to the total of the nickel and the at least one metal element is 30 mol % or more. The layer is composed such that the amount of the lithium carbonate is 0.5 to 5 mol per 100 mol of the lithium nickel composite oxide. The total of aluminum atoms contained in the aluminum hydroxide and the aluminum oxide is 0.5 to 5 mol per 100 mol of the lithium nickel composite oxide.

Positive electrode active material for non-aqueous electrolyte secondary battery, production method thereof, and non-aqueous electrolyte secondary battery using the same

A positive electrode active material, which gives a non-aqueous electrolyte secondary battery capable of high input/output where resistance due to a battery reaction in a low temperature environment is suppressed, is produced by a method comprising: (a)providing a nickel hydroxide which is represented by the general formula NiCoM(OH), (b)heating the nickel hydroxide at a temperature not lower than 600&#xb0; C. and not higher than 1000&#xb0; C. to produce a nickel oxide which is represented by the general formula NiCoMO; and (c)mixing the nickel oxide and a lithium compound to obtain a mixture and heating the mixture at a temperature not lower than 700&#xb0; C. and not higher than 850&#xb0; C. to produce a lithium-containing composite oxide which is represented by the general formula LiNiCoMO, where 0.1&#x2266;x&#x2266;0.35 and 0.03&#x2266;y&#x2266;0.2 are satisfied and M is at least one selected from the group consisting of Al, Ti and Sn.

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Utsunomiya, Japan

Takaya Saito