Abstract: 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 %.

Abstract: 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 SiOx and 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?y?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: ?C (mAhg?1) satisfies L=?C/100 and 6y?L?12y+0.2.

Abstract: 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.

Abstract: The nonaqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and a nonaqueous electrolytic solution and is characterized in that the nonaqueous electrolytic solution contains propylene carbonate and fluoroethylene carbonate, the positive electrode contains an oxide that contains lithium and one or more metallic elements M as a positive electrode active material, the one or more metallic elements M include at least one selected from the group consisting of cobalt and nickel, the negative electrode contains graphite as an active material, the negative electrode active material includes lithium and a lithium carbonate layer with a thickness of 1 ?m or less on the surface thereof, and the ratio of the total lithium content a of the positive and negative electrodes to the metallic element M content Mm of the oxide, a/Mm, is greater than 1.01.

Abstract: The generation of as in nonaqueous electrolyte secondary batteries during storage at elevated temperature is reduced to improve the elevated-temperature storage properties thereof. A nonaqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and a nonaqueous electrolyte solution. The positive electrode contains an oxide containing lithium and a metal element M. The metal element N is at least one element selected from the group consisting of cobalt and nickel. The negative electrode contains SiOx (where x=0.5 to 1.5), a graphite having a BET specific surface area of 10 m2/g, and a material having a BET specific surface area of 10 m2/g, or more. The ratio a/Mc of the total content a of lithium in the positive and negative electrodes to the content Mc of the metal element M in the oxide is greater than 1.01.

Abstract: 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 %.

Abstract: 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.

Abstract: A leak test defect is suppressed which is generated by short circuit between a positive electrode and a negative electrode with a lithium metal present in the vicinity of an end portion of a separator, and an initial charge/discharge efficiency of a lithium-ion cell and cycle characteristics thereof are improved. In the lithium-ion cell, the separator includes a polyolefin as a primary material and a uniform lithium metal film formed on a surface portion thereof which is located at the negative electrode plate side and which does not face the negative electrode active material layer, and the lithium metal film is electrically insulated from the positive electrode collector.

Abstract: 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%.

Abstract: A positive electrode plate 5, a separator 7, and a negative electrode plate 6 are prepared. The positive electrode plate 5, the separator 7, and the negative electrode plate 6 are combined so as to form a spirally-wound electrode assembly 4. A winding end portion 9 of the electrode assembly 4 is fixed with a heat-sensitive adhesive (preferably, a heat-sensitive adhesive tape 10) whose adhesive force can be reduced by heating or cooling. The electrode assembly 4 is placed in an outer casing 1, and then the ambient temperature of the electrode assembly 4 is adjusted so that the electrode assembly 4 is loosened due to reduction in the adhesive force of the heat-sensitive adhesive. An electrolyte solution is injected into the outer casing 1.

Abstract: 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 SiOx and 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?y?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: ?C (mAhg?1) satisfies L=?C/100 and 6y?L?12y+0.2.

Abstract: Disclosed is a non-aqueous electrolyte secondary battery including a positive electrode, a negative electrode, a non-aqueous electrolyte, and a battery case containing them. The negative electrode includes SiOx where 0.5<x<1.5, and a carbon material. The non-aqueous electrolyte includes a halogenated cyclic carbonate. A ratio of mass b of the halogenated cyclic carbonate included in the non-aqueous electrolyte to mass a of the SiOx included in the negative electrode satisfies 0.001<b/a<3. A percentage of the SiOx to the total of the SiOx and the carbon material included in the negative electrode is preferably more than or equal to 3 mass % and less than 40 mass %.

Abstract: 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<z<y.

Abstract: A positive electrode plate 5, a separator 7, and a negative electrode plate 6 are prepared. The positive electrode plate 5, the separator 7, and the negative electrode plate 6 are combined so as to form a spirally-wound electrode assembly 4. A winding end portion 9 of the electrode assembly 4 is fixed with a heat-sensitive adhesive (preferably, a heat-sensitive adhesive tape 10) whose adhesive force can be reduced by heating or cooling. The electrode assembly 4 is placed in an outer casing 1, and then the ambient temperature of the electrode assembly 4 is adjusted so that the electrode assembly 4 is loosened due to reduction in the adhesive force of the heat-sensitive adhesive. An electrolyte solution is injected into the outer casing 1.

Abstract: Charging of a lithium ion secondary battery including a positive electrode including a positive electrode active material capable of absorbing and releasing lithium ions, a negative electrode including a negative electrode active material being an alloy-formable active material capable of absorbing and releasing lithium ions, a separator interposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte is performed. In charging, the remaining capacity and the temperature of the lithium ion secondary battery are detected, and the lithium ion secondary battery is charged until the battery voltage reaches a reference voltage E1 associated beforehand with the remaining capacity and the temperature.

Abstract: 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%.

Abstract: A negative electrode for lithium ion secondary batteries, including: a negative electrode current collector having a plurality of protrusions formed on a surface thereof; and a plurality of granular bodies, the granular bodies being supported on the protrusions, respectively, and including an alloy-formable active material capable of absorbing and releasing lithium ions, wherein: the granular bodies have a resin layer on their respective surfaces; and the resin layer includes a first resin component which is at least one selected from polyimides and polyacrylic acid, and a second resin component which is composed of a copolymer including vinylidene fluoride units and hexafluoropropylene units. A lithium ion secondary battery including the above negative electrode.

Abstract: In a charge/discharge method for a positive-electrode active material in a lithium secondary battery, the lithium secondary battery includes a positive electrode containing a positive-electrode active material capable of occluding and releasing lithium ions, a negative electrode containing a negative-electrode active material capable of occluding and releasing lithium ions, a separator located between the positive electrode and the negative electrode, and an electrolyte having a lithium ion conductivity; and the positive-electrode active material contains a nickel-type lithium-containing complex oxide. The positive electrode, which has been charged, is discharged until having a first potential VDp1 which is no less than 2.7 V and no more than 3.4 V on a lithium metal basis, and then the discharge is finished. Owing to this, the charge/discharge cycle life can be improved while the capacity of the lithium secondary battery is secured.

Abstract: 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.

Abstract: A battery pack includes at least a lithium ion secondary battery, a voltage sensor, and a control unit. The control unit controls discharge of the battery by a relatively high end-of-discharge voltage when the use frequency of the battery is relatively low during discharge of the battery. On the other hand, the control unit controls discharge of the battery by a relatively low end-of-discharge voltage when the use frequency of the battery is relatively high. Consequently, it is possible to prevent the utilizable capacity from decreasing more than a practical decrease in the capacity due to increase in the use frequency.