Abstract: Provided is a lithium secondary battery in which negative-electrode active material particles containing silicon and/or a silicon alloy are used and which prevents the occurrence of breakage of a binder itself and peel-off of the binder at the interfaces with the negative-electrode active material and the negative-electrode current collector and has a high energy density and an excellent cycle characteristic. The lithium secondary battery includes: a negative electrode in which a negative-electrode active material layer including negative-electrode active material particles containing silicon and/or a silicon alloy and a binder is formed on a surface of electrically conductive metal foil serving as a negative-electrode current collector; a positive electrode; and a nonaqueous electrolyte, wherein the binder contains a polyimide resin including a crosslinked structure formed by imidization of a hexavalent or higher-valent carboxylic acid or an anhydride thereof with a diamine.

Abstract: This invention provides a negative electrode material for a rechargeable battery with a nonaqueous electrolyte, characterized in that the negative electrode material contains polycrystalline silicon particles as an active material, the particle diameter of crystallites of the polycrystalline silicon is not less than 20 nm and not more than 100 nm in terms of a crystallite size determined by the Scherrer method from the full width at half maximum of a diffraction line attributable to Si (111) around 2?=28.4° in an x-ray diffraction pattern analysis, and the true specific gravity of the silicon particles is 2.300 to 2.320.

Abstract: Provided is a lithium secondary battery in which negative-electrode active material particles containing silicon and/or a silicon alloy are used and which prevents the occurrence of breakage of a binder itself and peel-off of the binder at the interfaces with the negative-electrode active material and the negative-electrode current collector and has a high energy density and an excellent cycle characteristic. The lithium secondary battery includes: a negative electrode in which a negative-electrode active material layer including negative-electrode active material particles containing silicon and/or a silicon alloy and a binder is formed on a surface of electrically conductive metal foil serving as a negative-electrode current collector; a positive electrode; and a nonaqueous electrolyte, wherein the binder contains a polyimide resin including a crosslinked structure formed by imidization of a hexavalent or higher-valent carboxylic acid or an anhydride thereof with a diamine.

Abstract: A lithium secondary battery contains a negative electrode binder containing a polyimide resin having a structure represented by the following chemical formula (1), and the polyimide resin having a molecular weight distribution such that the weight ratio of a polyimide resin having a molecular weight of less than 100,000 and a polyimide resin having a molecular weight from 100,000 to less than 200,000 is from 50:50 to 90:10: where n is an integer equal to or greater than 1, and R is a functional group represented by the following chemical formula (2) or (3):

Abstract: A non-aqueous electrolyte secondary battery has a positive electrode (1), a negative electrode (2), a separator (3) interposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte solution in which a solute is dissolved in a non-aqueous solvent. The negative electrode contains a negative electrode active material capable of alloying with lithium and the non-aqueous solvent of the non-aqueous electrolyte solution contains one ore more fluorinated cyclic carbonates and a carboxylic ester. In addition, the non-aqueous electrolyte solution contains a nitrile compound having a chain saturated hydrocarbon group having two or more carbon atoms.

Abstract: Provided is a binder capable of realizing a lithium secondary battery that includes a negative electrode including a negative-electrode active material layer containing at least one of silicon and a silicon alloy as a negative-electrode active material and also containing a binder and has an excellent charge-discharge cycle characteristic. The binder for the lithium secondary battery contains a polyimide resin that is formed by imidizing either a tetracarboxylic acid or a tetracarboxylic anhydride and a diamine, the polyimide resin having a hydrolyzable silyl group.

Abstract: This invention provides a negative electrode material for a rechargeable battery with a nonaqueous electrolyte, characterized in that the negative electrode material contains polycrystalline silicon particles as an active material, the particle diameter of crystallites of the polycrystalline silicon is not less than 20 nm and not more than 100 nm in terms of a crystallite size determined by the Scherrer method from the full width at half maximum of a diffraction line attributable to Si (111) around 2?=28.4° in an x-ray diffraction pattern analysis, and the true specific gravity of the silicon particles is 2.300 to 2.320.

Abstract: A lithium secondary battery contains a negative electrode binder containing a polyimide resin having a structure represented by the following chemical formula (1), and the polyimide resin having a molecular weight distribution such that the weight ratio of a polyimide resin having a molecular weight of less than 100,000 and a polyimide resin having a molecular weight from 100,000 to less than 200,000 is from 50:50 to 90:10: where n is an integer equal to or greater than 1, and R is a functional group represented by the following chemical formula (2) or (3):

Abstract: A non-aqueous electrolyte secondary battery has a positive electrode (1), a negative electrode (2), a separator (3) interposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte solution in which a solute is dissolved in a non-aqueous solvent. The negative electrode contains a negative electrode active material capable of alloying with lithium and the non-aqueous solvent of the non-aqueous electrolyte solution contains one ore more fluorinated cyclic carbonates and a carboxylic ester. In addition, the non-aqueous electrolyte solution contains a nitrile compound having a chain saturated hydrocarbon group having two or more carbon atoms.

Abstract: The present invention provides a nonaqueous electrolyte secondary cell having a construction wherein a flat spiral-shaped electrode assembly, in which positive and negative electrodes capable of intercalating and deintercalating lithium ions are wound with a separator disposed therebetween, is enclosed in a casing which changes shape with a slight increase in the internal pressure of the cell, a gel polymer containing a nonaqueous liquid electrolyte exists between the positive electrode and the separator, bonding the positive electrode and the separator, and the adhesive strength between the separator and the positive electrode is 0.02 N/10 mm or higher. In the above construction of a nonaqueous electrolyte secondary cell, even when the cell is overcharged and gas is generated in the cell, explosion caused by detachment of the bonded portion of the positive electrode and the separator is prevented.

Abstract: The present invention provides a nonaqueous electrolyte secondary cell using, as a cell casing, a film-like casing, in which pressure exerted by the structure of the casing is low, and a gel electrolyte including a polymer, a nonaqueous solvent, and an electrolyte salt. The cell inhibits an internal short-circuit caused by heat shrinkage of a separator and improves safety of the cell, by, for example, making the construction one in which the heat shrinkage rate in the width direction of the separator when heated to 130° C. is controlled to 50% or less and the weight percentage of the polymer in relation to the total weight of a component of the nonaqueous solvent with a boiling point of over 130° C.

Abstract: The present invention provides a nonaqueous electrolyte secondary cell having a construction wherein a flat spiral-shaped electrode assembly, in which positive and negative electrodes capable of intercalating and deintercalating lithium ions are wound with a separator disposed therebetween, is enclosed in a casing which changes shape with a slight increase in the internal pressure of the cell, a gel polymer containing a nonaqueous liquid electrolyte exists between the positive electrode and the separator, bonding the positive electrode and the separator, and the adhesive strength between the separator and the positive electrode is 0.02 N/10 mm or higher. In the above construction of a nonaqueous electrolyte secondary cell, even when the cell is overcharged and gas is generated in the cell, explosion caused by detachment of the bonded portion of the positive electrode and the separator is prevented.