Abstract: A negative electrode active material layer (243A) of a lithium-ion secondary battery (100A) contains natural graphite and artificial graphite as negative electrode active material particles. The negative electrode active material layer (243A) has a region (A1) facing the positive electrode active material layer (223) and regions (A2, A3) not facing the positive electrode active material layer (223). The region (A1) facing the positive electrode active material layer (223) contains the natural graphite in a larger proportion than the regions (A2, A3) not facing the positive electrode active material layer (223), and the regions (A2, A3) not facing the positive electrode active material layer (223) contain the artificial graphite in a larger proportion than the region (A1) facing the positive electrode active material layer (223).

Abstract: A hermetically sealed lithium secondary battery is provided which has an excellent battery performance and in which a current-interrupt mechanism operates accurately when overcharging occurs. This battery comprising an electrode assembly 80 that has a positive electrode 10. The positive electrode 10 has a positive electrode current collector 12, a positive electrode mixture layer 14 formed on the current collector, and a positive electrode assist layer 16 formed on the current collector and adjacent to the positive electrode mixture layer 14.

Abstract: A lithium-ion secondary battery (100A) has a negative electrode current collector (241A) and a negative electrode active material layer (243A) formed on the negative electrode current collector (241A). The negative electrode active material layer (243A) contains a graphite material and a binder. The negative electrode active material layer (243A) has a first region (A1) neighboring the negative electrode current collector (241A), and the first region (A1) contains natural graphite in a weight ratio of equal to or greater than 80% of the graphite material. The negative electrode active material layer (243A) has a second region (A2) neighboring a surface thereof, and the second region (A2) contains artificial graphite in a weight ratio of equal to or greater than 80% of the graphite material.

Abstract: A Lithium-ion secondary battery (100A) has a negative electrode current collector (241A) and a negative electrode active material layer (243A) coated on the negative electrode current collector (241A). The negative electrode active material layer (243A) contains negative electrode active material particles (710A). The negative electrode active material particles (710A) include graphite particles each at least partially covered by an amorphous carbon film (750). The weight ratio X of the amorphous carbon film (750) in the negative electrode active material particles (710A) is 0.02?X?0.06. The negative electrode active material particles (710A) have a linseed oil absorption number Y (mL/100 g) of 35 (mL/100 g)?Y?70 (mL/100 g).

Abstract: A negative electrode sheet of a lithium-ion secondary battery has a negative electrode current collector and a negative electrode active material layer on the negative electrode current collector. The negative electrode active material layer contains flake graphite particles and has a first region neighboring the negative electrode current collector and a second region neighboring a surface side that are different in perpendicularity of the graphite particles. The perpendicularity of the graphite particles is defined as (m1/m2), where, when the inclination ?n of each of the graphite particles is specified relative to a surface of the negative electrode current collector, m1 is the number of the graphite particles having an inclination ?n of 60°??n?90° and m2 is the number of the graphite particles having an inclination ?n of 0°??n?30°.

Abstract: Disclosed is an electrode (30) (for example, a positive electrode for a lithium ion battery), wherein an active material layer (35) mainly composed of an electrode active material is supported by a metal collector (32). A barrier layer (33) containing a conductive material (330) and a water-insoluble polymer material (334) are formed on the surface of the metal collector (32). The conductive material (330) contains at least a first conductive powder (331) having a certain average particle diameter, and a second conductive powder (332) having an average particle diameter larger than that of the first conductive powder. The ratio of the first conductive powder (331) contained in the barrier layer (33) is higher than that of the second conductive powder (332).

Abstract: A lithium ion secondary battery 100A has negative electrode active material particles 710A which include graphite particles that are at least partially covered by an amorphous carbon film 750. The negative electrode, active material particles 710A have a TG weight-loss-on-heating onset temperature T1 which satisfies the condition 500° C.?T1?615° C. and a micro-Raman G-band half-width Gh which satisfies the condition 20?Gh?28. This configuration makes it possible to obtain a lithium ion secondary battery 100A in which the reaction resistance in a low-temperature environment can be kept low.

Abstract: In a lithium ion secondary battery, a negative electrode sheet is made of a metal foil and an active material layer containing active material particles. The negative active material layer includes a facing portion that faces a positive active material layer and a non-facing portion that does not face the same. The negative active material particles can be oriented in a magnetic field direction. When an angle between an extending direction of a major axis of the cross section of each particle and the metal foil is ?, the number of particles with the angle ? of 60°-90° is MA, the number of negative active material particles with the angle ? of 0°-30° is MB, and a value MA/MB is assumed to be an orientation degree (AL) of particles, the negative active material layer is made such that an orientation degree (AL1) in the non-facing portion is 1.2 or more.

Abstract: A lithium-ion secondary battery (100) includes a positive electrode mixture layer (223) coated on a positive electrode current collector (221), a negative electrode mixture layer (243) coated on a negative electrode current collector (241), and an electrolyte solution containing lithium ions at a predetermined concentration. The number of lithium ions X in the electrolyte solution impregnated per 1 cm3 of the positive electrode mixture layer (223) and the number of lithium ions Y in the electrolyte solution impregnated per 1 cm3 of the negative electrode mixture layer (243) are both 3.75×1019 or greater.

Abstract: A secondary battery is provided with a negative electrode sheet including a negative active material layer including negative active material particles. The negative active layer contains, as the negative active material particles, graphite particles formed from graphite and amorphous carbon particles formed from amorphous carbon. The difference (?S)(=Sb?Sa) in specific surface area between the specific surface area (Sb) of the amorphous carbon particles and the specific surface area (Sa) of the graphite particles is ?0.3 to 2.6 m2/g.

Abstract: The present invention provides a method of manufacturing a nonaqueous electrolyte secondary battery in which graphite fissuring during rolling of the negative electrode mixture layer is prevented and a deterioration in the performance of the battery is thereby suppressed.

Abstract: There is provided a lithium ion secondary cell excellent in charging and discharging cycle characteristics. A lithium ion secondary cell includes an electrode body including a positive electrode having a positive electrode active material, a negative electrode having a negative electrode active material, and a separator, and a non-aqueous electrolyte containing a lithium salt as a supporting salt in an organic solvent, the electrode body and the non-aqueous electrolyte being accommodated in a case. The positive electrode active material is a lithium transition metal oxide having a spinel type structure. The electrolyte contains a compound represented by a chemical formula (I) in an amount of ? mol relative to the total content ? mol of moisture to be mixed in the cell. ? satisfies ?0.8?log(?/?)?1.5.

Abstract: The present invention provides a method for producing a lithium-ion secondary battery with excellent high-temperature storage characteristics. The method for producing the lithium-ion secondary battery provided by the present invention includes a step of assembling a lithium-ion secondary battery using positive and negative electrodes, and a nonaqueous electrolyte containing in an organic solvent a lithium salt as a supporting salt, at least one type of substance selected from carboxylic acid anhydrides and dicarboxylic acids as additive A, and at least one type of substance selected from vinylene carbonate, vinylethylene carbonate, ethylene sulfite, and fluoroethylene carbonate as additive B; a step of carrying out initial charging of the assembled battery to a predetermined voltage; and a step of carrying out an aging treatment by keeping the battery at a temperature of 35° C. or higher for 6 hours or longer.

Abstract: An electrode plate includes a current collector plate and an active material layer formed thereon. The active material layer includes, as a binder, a plurality of binders having different glass transition points (Tg) from each other. A ratio (A2/A1) between the amount of a binder contained in a surface section and the amount of a binder contained in a current collector plate section is 1.0 to 1.2. Further, an average glass transition point (Tgu) of the binder in the surface section is lower than an average glass transition point (Tgd) of the binder in the current collector plate section (Tgu<Tgd).

Abstract: A lithium ion secondary battery involves a negative electrode sheet including a negative current collector and a negative active material layer that contains negative active material particles including first particles and second particles. In the negative active material layer, the ratio of the first particles to the total negative active material particles in a part on the current collector side in the layer thickness direction of the negative active material layer is higher than the ratio of the first particles to the total negative active material particles in the whole negative active material layer and the ratio of the second particles to the total negative active material particles in a part on an outer surface side of the negative active material layer in the layer thickness direction is higher than the ratio of the second particles to the total negative active material particles in the whole negative active material layer.

Abstract: A method for producing a lithium-ion secondary battery comprising positive and negative electrodes and a non-aqueous electrolyte solution is provided. The method comprises (A) with several different negative electrode active materials, determining density Xn (g/cm3) at several different number of taps applied, n, respectively; (B) determining density Y (g/cm3) of a negative electrode active material layer constituted with a mixture comprising each negative electrode active material; (C) based on a regression line, Y=aXn+b, determining the number of taps applied, n?, that gives a?0.5 and a determination coefficient R2?0.99; (D) based on a plot of Y=aXa?+b, determining a passing range of Xn? where negative electrode active material layer density Y is in a prescribed range; (E) selecting a negative electrode active material having Xn?in the passing range, and fabricating a negative electrode with this material.

Abstract: An objective is to reduce the sheet resistance and gas evolution in a battery electrode comprising a conductive intermediate layer capable of reducing or shutting off a current when overcharged. A battery electrode (12) comprises a conductive intermediate layer (123) being placed between a current collector (122) and an active layer (124) while comprising conductive particles (50) and a binder (60). The mass proportion of conductive particles (50) is equal to or larger than the mass proportion of the binder (60). Conductive particles (50) has a size distribution that exhibits a first peak with the maximum at a first particle diameter value and a second peak with the maximum at a second particle diameter value larger than the first particle diameter value. The intermediate layer (123) contains 10% to 60% by mass of conductive particles (52) having particle diameters that belong to the second peak.

Abstract: A main object of the present invention to provide a nonaqueous electrolyte secondary battery having high durability towards charge and discharge cycles, by preventing buckling of a wound electrode body. The secondary battery provided by the present invention comprises: a nonaqueous electrolyte; and a wound electrode body 80 configured by superposing on each other, and winding a positive electrode sheet 10 having a positive electrode collector formed to a sheet shape and a positive electrode active material layer formed on that collector, a, negative electrode sheet 20 having a negative electrode collector formed to a sheet shape and a negative electrode active material layer formed on that collector, and a separator 40 formed to a sheet shape. The negative electrode active material contained in the negative electrode active material layer is oriented in a predetermined direction.

Abstract: A lithium secondary battery obtained by the present invention has a negative electrode sheet 20 in which the theoretical capacities of the negative active material per unit area are equalized in a negative active material layer 24b on the outer circumference side and a negative active material layer 24a on the inner circumference side of a negative electrode collector 22, and at least one of the following conditions is met with respect to at least part of a bent section 85, which is bent toward the inside of a wound electrode body 80: (1) the percentage content of binder of the outer negative active material layer 24b is smaller than the percentage content of binder of the inner negative active material layer 24a; and (2) the density of the outer negative active material layer 24b is smaller than the density of the inner negative active material layer 24a.

Abstract: Provided is a method for negative electrode active material evaluation useful for steady production of batteries having a prescribed performance level. This evaluation method comprises: (A) running microscopic Raman analysis at a wavelength of 532 nm n times on a sample of a composite carbon comprising a low-crystalline carbon material at least partially on surfaces of particles of a high-crystalline carbonaceous substance (wherein n is 20 or more); (B) with respect to a Raman spectrum obtained in each microscopic Raman analysis run, determining the ratio of its D-band intensity ID to its G-band intensity IG, R (ID/IG); (C) determining the number of analysis runs, m, where the R value was 0.2 or greater, and (D) determining the ratio of m to n, the total number of analysis runs.