Abstract: A lithium secondary battery has a positive electrode, a separator, and a negative electrode having a negative electrode current collector and a negative electrode mixture layer formed on a surface of the negative electrode current collector. The negative electrode mixture layer contains a negative electrode active material including a metal element capable of alloying with lithium. The negative electrode current collector includes a substrate made of a Cu—Fe—P alloy foil, and a surface layer provided on both surfaces of the substrate and made of pure copper. The surface layer has a Vickers hardness of 120 and less than that of the substrate. The negative electrode current collector has a proof stress of 308 MPa.

Abstract: A lithium secondary battery has a wound electrode assembly (5). The wound electrode assembly (5) has a negative electrode (2) 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 (1) having a positive electrode active material layer containing a positive electrode active material made of a transition metal composite oxide, a separator (3) disposed between the positive and negative electrodes and having a penetration resistance of 500 g or greater, and a cylindrical hollow space (14) at a winding axis and in the vicinity thereof, wherein the positive electrode (1), the negative electrode (2), and the separator (3) are spirally wound. A columnar center pin (15) having a diameter of from 75% to 95% of the diameter of the hollow space is disposed in the hollow space.

Abstract: A negative electrode for lithium secondary batteries includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer is formed on the negative electrode current collector. The negative electrode active material layer contains a binder and negative electrode active material particles containing at least one of silicon and a silicon alloy. The binder is a polyimide resin formed by imidization of a tetracarboxylic acid or tetracarboxylic anhydride and a diamine. The diamine contains a diamine having at least one hydroxyl group.

Abstract: A nonaqueous electrolyte secondary battery includes a positive electrode having a positive-electrode active material, a negative electrode having a negative-electrode active material, and a nonaqueous electrolytic solution having a nonaqueous solvent dissolving a solute. The negative-electrode active material includes powdered silicon and/or a silicon alloy, the nonaqueous electrolytic solution includes additives composed of at least one fluorinated lithium phosphate selected from the group consisting of lithium monofluorophosphate, lithium difluorophosphate, and lithium trifluorophosphate and a diisocyanate compound, and the nonaqueous solvent includes a chain carbonate compound.

Abstract: A lithium secondary battery comprises an electrode assembly and a non-aqueous electrolyte. The electrode assembly is made by winding a negative electrode, a positive electrode, and a separator interposed between the negative and positive electrodes. The negative electrode contains a negative electrode active material that is alloyed with lithium. The non-aqueous electrolyte is impregnated in the electrode assembly. At least one of the negative and positive electrodes is divided into a plurality of electrode units which are arranged at spaces for each other along the winding direction.

Abstract: A non-aqueous electrolyte secondary battery includes a positive electrode (1), a negative electrode (2) containing a negative electrode active material, a separator 3 interposed between the electrodes (1) and (2), and a non-aqueous electrolyte containing a non-aqueous solvent and a solute dissolved in the solvent. The non-aqueous electrolyte contains a compound represented by the following chemical formula (1): wherein n is an integer of from 2 to 6, each R represents a linear saturated hydrocarbon that may be an unsubstituted or may have a substituted group, and the Rs may be the same or different groups.

Abstract: The present invention is made to improve charge-discharge cycle performances under high temperature environment in a non-aqueous electrolyte secondary battery using a negative electrode containing a negative electrode active material of particulate silicon and/or silicon alloy and a binding agent.

Abstract: A lithium secondary battery including an electrode assembly and a non-aqueous electrolyte impregnated in the electrode assembly, the electrode assembly containing a positive electrode, a negative electrode having a negative electrode current collector and a negative electrode mixture layer formed on the negative electrode current collector, the negative electrode mixture layer containing a binder and negative electrode active material particles, the negative electrode active material particles containing at least one of silicon and a silicon alloy, and a separator interposed between the negative electrode and the positive electrode. The binder contains a polyimide resin having a branch structure formed by imidizing a polyvalent amine having a valency of 3 or more and a tetracarboxylic dianhydride.

Abstract: A lithium ion secondary battery 1 includes a spirally wound electrode assembly 20 and a cylindrical battery container 10. The spirally wound electrode assembly 20 includes a negative electrode 21, a positive electrode 22 and a separator 23. The negative electrode 21 includes negative-electrode active material layers 21b and 21c containing a negative-electrode active material capable of forming an alloy with lithium. The lithium ion secondary battery 1 includes an urging part 20a. The urging part 20a is disposed in the center of and in contact with the spirally wound electrode assembly 20. The urging part 20a is contractible in diameter. The urging part 20a is configured to urge the spirally wound electrode assembly 20 radially outward at least when contracting in diameter.

Abstract: A negative electrode (2) for a lithium secondary battery having a negative electrode current collector (21) having an arithmetical mean surface roughness Ra of 0.01 ?m or greater and a negative electrode active material layer (22) formed on the negative electrode current collector (21). The negative electrode active material layer (22) contains a negative electrode active material (22a) including a material capable of alloying with lithium. A conductive layer (23) including a material not intercalating or deintercalating lithium is formed on the negative electrode active material layer.

Abstract: A non-aqueous electrolyte secondary battery has a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte dissolving a solute in a non-aqueous solvent wherein the negative electrode contains a negative electrode active material containing powdered silicon and/or silicon alloy and a binding agent, and the non-aqueous electrolyte contains a fluorinated cyclic carbonate represented by a general formula (1) below, and wherein when Li storage volume per unit area in the negative electrode during charging is determined as A and the theoretical maximum Li storage volume per unit area in the negative electrode is determined as B, a utilizing rate (%) of negative electrode as expressed by (A/B)×100 is 45% or less.

Abstract: A lithium secondary battery having high capacity and good charge-discharge cycle performance is provided. The lithium secondary battery includes a negative electrode (2) containing silicon as a negative electrode active material, a positive electrode (1) containing a positive electrode active material, and a non-aqueous electrolyte. The positive electrode active material is a lithium-transition metal composite oxide including a layered structure represented by the chemical formula LiaNixMnyCozO2, where a, x, y, and z satisfy the expressions: 0?a?1.3, x+y+z=1, 0<x, 0?y?0.5, and 0?z.), and the theoretical electrical capacity ratio of the positive electrode to the negative electrode (positive electrode/negative electrode) is 1.2 or less.

Abstract: Charge-discharge cycle performance is improved in a lithium secondary battery that adopts a thin film made of silicon or a silicon alloy as its negative electrode active material and has a wound electrode structure. The lithium secondary battery includes: a negative electrode having a current collector and a thin film made of silicon or a silicon alloy as a negative electrode active material, the thin film provided on the current collector; a positive electrode; a separator; the positive and negative electrodes being overlapped with the separator interposed therebetween, and the positive and negative electrodes and the separator being wound around to form an electrode assembly; a non-aqueous electrolyte; and a battery case accommodating the electrode assembly. The ratio of theoretical capacity per unit area of the negative electrode to charge capacity per unit area of the positive electrode is within the range of from 1.9 to 4.4.

Abstract: A non-aqueous electrolyte secondary battery includes a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode and a non-aqueous electrolyte. The negative electrode comprises a negative electrode active material to be alloyed with lithium and the non-aqueous electrolyte comprises a non-aqueous solvent containing fluorinated cyclic carbonate and propyl acetate.

Abstract: A lithium secondary battery has a wound electrode assembly (5). The wound electrode assembly (5) has a negative electrode (2) 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 (1) having a positive electrode active material layer containing a positive electrode active material made of a transition metal composite oxide, a separator (3) disposed between the positive and negative electrodes and having a penetration resistance of 500 g or greater, and a cylindrical hollow space (14) at a winding axis and in the vicinity thereof, wherein the positive electrode (1), the negative electrode (2), and the separator (3) are spirally wound. A columnar center pin (15) having a diameter of from 75% to 95% of the diameter of the hollow space is disposed in the hollow space.

Abstract: A cylindrical lithium secondary battery includes a positive electrode (1) having a positive electrode mixture layer disposed on a surface of a positive electrode current collector made of a conductive metal foil and containing a positive electrode active material, and a negative electrode (2) having a negative electrode mixture layer disposed on a surface of a negative electrode current collector made of a conductive metal foil and having a negative electrode active material containing silicon particles and/or silicon alloy particles. The amount of the positive electrode active material is 50 mg or less per 1 cm2 of the positive electrode, the average particle size of the silicon particles and/or silicon alloy particles is from 5 ?m to 15 ?m, and the theoretical electrical capacity ratio of the negative electrode to the positive electrode is 1.2 or greater.

Abstract: A nonaqueous electrolyte secondary battery which includes a positive electrode, a negative electrode and a separator stacked and wound in a cylindrical configuration, and which achieves a high energy density and superior cycle performance characteristics. The nonaqueous electrolyte secondary battery includes a positive electrode containing a positive active material, a negative electrode containing a negative active material, a separator interposed between the positive electrode and the negative electrode, and a nonaqueous electrolyte containing a solvent and a solute. Those positive electrode, negative electrode and separator are stacked and wound in a cylindrical configuration. Characteristically, the negative active material comprises a material that stores lithium via alloying with lithium, the solvent in the nonaqueous electrolyte contains a fluorinated cyclic carbonate, and the nonaqueous electrolyte has a viscosity of not higher than 2.5 mPas.

Abstract: A lithium secondary battery is provided capable of significantly improving charge-discharge cycle performance by preventing gas generation originating from decomposition of the non-aqueous electrolyte while preventing manufacturing cost from increasing. A lithium secondary battery is provided with: a power generating element accommodated in a flexible battery case (6), the power generating element including a negative electrode (2), a positive electrode (1), and a non-aqueous electrolyte. The negative electrode contains negative electrode active material particles composed of silicon and/or a silicon alloy. The positive electrode contains a positive electrode active material composed of a lithium-transition metal composite oxide. The non-aqueous electrolyte contains ions of at least one element selected from the group consisting of Co, Cu, Mg, Mn, Ni, Fe, and Zr.

Abstract: Charge-discharge cycle performance is improved in a lithium secondary battery that adopts a thin film made of silicon or a silicon alloy as its negative electrode active material and has a wound electrode structure. The lithium secondary battery includes: a negative electrode having a current collector and a thin film made of silicon or a silicon alloy as a negative electrode active material, the thin film provided on the current collector; a positive electrode; a separator; the positive and negative electrodes being overlapped with the separator interposed therebetween, and the positive and negative electrodes and the separator being wound around to form an electrode assembly; a non-aqueous electrolyte; and a battery case accommodating the electrode assembly. The ratio of charge capacity per unit area of the negative electrode to theoretical capacity per unit area of the positive electrode is within the range of from 1.9 to 4.4.

Abstract: A lithium secondary battery having high capacity and good charge-discharge cycle performance is provided. The lithium secondary battery includes a negative electrode (2) containing silicon as a negative electrode active material, a positive electrode (1) containing a positive electrode active material, and a non-aqueous electrolyte. The positive electrode active material is a lithium-transition metal composite oxide including a layered structure represented by the chemical formula LiaNixMnyCOzO2, where a, x, y, and z satisfy the expressions: 0?a?1.3, x+y+z=1, 0<x, 0?y?0.5, and 0?z.), and the theoretical electrical capacity ratio of the positive electrode to the negative electrode (positive electrode/negative electrode) is 1.2 or less.