Abstract: Provided is a nonaqueous electrolyte secondary battery having both high output characteristics and high capacity deterioration resistance in repetitive charge and discharge with a large current. A nonaqueous electrolyte secondary battery disclosed here includes a positive electrode, a negative electrode, and a nonaqueous electrolyte. The positive electrode includes a positive electrode current collector and a positive electrode active material layer supported by the positive electrode current collector. The positive electrode active material layer contains a positive electrode active material and carbon nanotubes. The nonaqueous electrolyte contains a nonaqueous solvent and a supporting electrolyte. The nonaqueous solvent contains 2 to 9 volume % of a carboxylate ester that has 6 or less carbon atoms and may be optionally substituted by a fluorine atom.

Abstract: Provided is a negative electrode using graphite as a negative electrode active material and using carbon nanotubes as a conductive material. The negative electrode can suppress a change in thickness of the negative electrode in repetitive charge and discharge of a secondary battery and provides the secondary battery with excellent high-temperature storage characteristics. The negative electrode disclosed here includes a negative electrode current collector and a negative electrode active material layer supported on the negative electrode current collector. The negative electrode active material layer includes a negative electrode active material and single-wall carbon nanotubes. The negative electrode active material consists essentially of graphite. A mass proportion of the single-wall carbon nanotubes to the negative electrode active material is 0.02 mass % or more and 0.08 mass % or less.

Abstract: Provided is a negative electrode that can reduce a dimensional change of an electrode body in repetitive charge and discharge of a secondary battery and can reduce an internal resistance in performing high-rate discharge on the secondary battery. The negative electrode disclosed here includes a negative electrode current collector, a negative electrode active material layer disposed on the negative electrode current collector, and a coating layer disposed on the negative electrode active material layer. The negative electrode active material layer includes artificial graphite. The coating layer includes natural graphite. A thickness ratio between the coating layer and the negative electrode active material layer is 3:97 to 28:72. Each of the negative electrode active material layer and the coating layer includes a rubber-based binder, and a water-soluble cellulose derivative.

Abstract: A method for manufacturing a positive electrode disclosed here includes: a CNT paste preparing step of preparing a CNT paste containing at least carbon nanotubes (CNT) and a dispersing agent; a magnetic separating step of exerting a magnetic force on the CNT paste to adsorb metal existing inside the CNTs and separating the CNTs and the metal; a positive electrode active material layer forming paste preparing step of mixing the CNTs subjected to the magnetic separating step, a positive electrode active material, and a binder to prepare a positive electrode active material layer forming paste; and a positive electrode active material layer forming step of applying the prepared positive electrode active material layer forming paste to a positive electrode current collector to form a positive electrode active material layer on the positive electrode current collector.

Abstract: Provided is a positive electrode capable of increasing capacity and output of a nonaqueous electrolyte secondary battery. A positive electrode disclosed here includes a positive electrode current collector and a positive electrode active material layer supported by the positive electrode current collector. The positive electrode active material layer includes particles of a lithium composite oxide having a layered structure as a positive electrode active material. The positive electrode active material layer has a porosity of 17% to 20%. A peak pore size in pore distribution of the positive electrode active material layer measured by mercury intrusion porosimetry is 0.400 ?m to 0.550 ?m.

Abstract: A nonaqueous electrolyte secondary battery includes a negative electrode mixture layer formed on a negative electrode current collector. The negative electrode mixture layer includes a first layer and a second layer. The first layer is formed on the negative electrode current collector and includes a negative electrode active material and a first binding agent. The negative electrode active material in the first layer includes a carbon material A and a Si-containing compound. The second layer is formed on the first layer and includes a negative electrode active material and a second binding agent. The negative electrode active material in the second layer includes a carbon material B. The carbon material B has a tap density higher than a tap density of the carbon material A. A packing density of the second layer is lower than a packing density of the first layer.

Abstract: This positive electrode for nonaqueous electrolyte secondary batteries is provided with a positive electrode core body and a positive electrode mixture layer that is formed on the surface of the positive electrode core body. The positive electrode mixture layer has a void fraction of from 23% by volume to 50% by volume; the positive electrode mixture layer contains at least a positive electrode active material, carbon nanotubes serving as a conductive assistant, and a polyvinylidene fluoride serving as a binder; the carbon nanotubes have a particle diameter of from 5 nm to 40 nm and an aspect ratio of from 100 to 1,000; the content of the carbon nanotubes in the positive electrode mixture layer is from 0.2% by mass to 5% by mass; and the number of polyvinylidene fluoride molecules contained per unit mass of the positive electrode mixture layer is from 0.005 to 0.030.

Abstract: A secondary battery having a suppressed decrease in capacity, even through rapid charging, includes: a positive electrode; a negative electrode including a negative electrode current collector and a negative electrode active material layer formed thereon containing a carbon material and silicon compounds; and an electrolyte solution containing nonaqueous solvents including 10 volume % or more of fluoroethylene carbonate. When: a surface of the negative electrode active material layer that faces the negative electrode current collector and the back side thereof are set as first and second surfaces, respectively; a thickness of the negative electrode active material layer is set as T; and regions from the first and the second surfaces to a depth of 0.5T are set as lower and upper layer portions, respectively, mass M1 of the silicon compounds in the lower layer portion is larger than mass M2 of the silicon compounds in the upper layer portion.

Abstract: This prismatic non-aqueous electrolyte secondary battery is provided with a negative electrode and a nonaqueous electrolyte. The negative electrode is provided with a negative electrode current collector and a negative electrode mixture layer formed on the negative electrode current collector. The negative electrode mixture layer comprises a first layer containing a first carbon active material, a Si active material and a polyacrylic acid or a salt thereof, and a second layer containing a second carbon active material. The nonaqueous solvent configuring the nonaqueous electrolyte contains a cyclic carbonate. The total content of the cyclic carbonate is 20-30 vol % of the total volume of the nonaqueous solvent, and the content of the ethylene carbonate belonging to the cyclic carbonate is less than or equal to 10 vol % of the total volume of the nonaqueous solvent. The nonaqueous electrolyte contains vinylene carbonate.

Abstract: A non-aqueous electrolyte secondary battery includes an electrode body in which a plurality of positive electrodes and a plurality of negative electrodes are alternately stacked with a separator interposed therebetween, and a non-aqueous electrolytic solution containing a non-aqueous solvent. The electrode body has 8 or more layers of pairs of a positive electrode and a negative electrode. The non-aqueous electrolytic solution contains, at 25° C, 10 to 40% by volume of a fluoroethylene carbonate and 15 to 40% by volume of a chain carboxylate ester having 5 or less carbon atoms, relative to the total volume of the non-aqueous solvent.

Abstract: A nonaqueous electrolyte secondary battery includes a negative electrode mixture layer formed on a negative electrode current collector. The negative electrode mixture layer includes a first layer and a second layer. The first layer is formed on the negative electrode current collector and includes a negative electrode active material and a first binding agent. The negative electrode active material in the first layer includes a carbon material A and a Si-containing compound. The second layer is formed on the first layer and includes a negative electrode active material and a second binding agent. The negative electrode active material in the second layer includes a carbon material B. The carbon material B has a tap density higher than a tap density of the carbon material A. A packing density of the second layer is lower than a packing density of the first layer.

Abstract: A secondary battery having a suppressed decrease in capacity, even through rapid charging, includes: a positive electrode; a negative electrode including a negative electrode current collector and a negative electrode active material layer formed thereon containing a carbon material and silicon compounds; and an electrolyte solution containing nonaqueous solvents including 10 volume % or more of fluoroethylene carbonate. When: a surface of the negative electrode active material layer that faces the negative electrode current collector and the back side thereof are set as first and second surfaces, respectively; a thickness of the negative electrode active material layer is set as T; and regions from the first and the second surfaces to a depth of 0.5T are set as lower and upper layer portions, respectively, mass M1 of the silicon compounds in the lower layer portion is larger than mass M2 of the silicon compounds in the upper layer portion.