Abstract: A charging device includes a charge-discharge circuit, a control device, and a communication device. The charge-discharge circuit is configured to charge and discharge the secondary battery. The control device is configured to control the charge-discharge circuit. The communication device is configured to communicate with an outside.

Abstract: A secondary battery includes a positive electrode, a negative electrode, and an electrolytic solution. The positive electrode includes a lithium-cobalt composite oxide having a layered rock-salt crystal structure. The negative electrode includes graphite. A potential variation of the positive electrode is greater than or equal to 2 mV when the secondary battery is discharged from a full charge state by a capacity corresponding to 1% of a maximum discharge capacity. The maximum discharge capacity is a discharge capacity obtained when the secondary battery is discharged with a constant current from the full charge state until the closed circuit voltage reaches 3.00 V, following which the secondary battery is discharged with a constant voltage of the closed circuit voltage of 3.00 V for 24 hours.

Abstract: A positive electrode active material includes positive electrode active material particles including a composite oxide with a hexagonal crystal structure. The composite oxide includes Li, Co, and at least one element M1 selected from the group consisting of Ni, Fe, Pb, Mg, Al, K, Na, Ca, Si, Ti, Sn, V, Ge, Ga, B, As, Zr, Mn and Cr, and the at least one element M1 is provided on a surface of the positive electrode active material particles. An atomic ratio of a total amount of the at least one element M1 to an amount of Co on the surface of the positive electrode active material particles is from 0.6 to 1.3.

Abstract: A parameter measurement unit measures intrinsic parameters of a plurality of used secondary batteries. A degradation degree calculation unit calculates degradation degrees of the plurality of used secondary batteries from the intrinsic parameter. A target degradation degree determination unit determines a target degradation degree from the degradation degrees of the plurality of used secondary batteries. An aging condition determination unit determines aging conditions of the plurality of used secondary batteries using the degradation degrees of the plurality of used secondary batteries and the target degradation degree. The aging processing unit performs aging processing on the plurality of used secondary batteries under the aging condition for each of the plurality of used secondary batteries.

Abstract: A positive electrode active material includes powder of composite particles including a lithium transition metal composite oxide having a lamellar rock-salt structure and a spinel phase. The spinel phase includes an oxide including lithium and at least a first element X1 selected from the group consisting of magnesium, aluminum, titanium, manganese, yttrium, zirconium, molybdenum, and tungsten, and the lithium transition metal composite oxide includes nickel or cobalt and the first element X1.

Abstract: A secondary battery includes a positive electrode, a negative electrode, and an electrolytic solution. The positive electrode includes a lithium-cobalt composite oxide having a layered rock-salt crystal structure. The negative electrode includes graphite. A potential variation of the positive electrode is greater than or equal to 2 mV when the secondary battery is discharged from a full charge state by a capacity corresponding to 1% of a maximum discharge capacity. The maximum discharge capacity is a discharge capacity obtained when the secondary battery is discharged with a constant current from the full charge state until the closed circuit voltage reaches 3.00 V, following which the secondary battery is discharged with a constant voltage of the closed circuit voltage of 3.00 V for 24 hours.

Abstract: Provided is a nonaqueous electrolyte secondary battery including a positive electrode, a negative electrode, and an electrolyte. The positive electrode includes positive active material particles having a layered rock salt type crystal structure. A filling ratio of the positive active material particles in the positive electrode is 85% or more. The positive active material particles include broken particles in which a longest diameter is within a range from 15 ?m to 30 ?m. A crack with a length ? times or more and ? times or less the longest diameter of the broken particles is present. The crack has an intersection, and an abundance ratio x of broken particle is 20% or less.

Abstract: A positive electrode active material includes positive electrode active material particles including a composite oxide with a hexagonal crystal structure. The composite oxide includes Li, Co, and at least one element M1 selected from the group consisting of Ni, Fe, Pb, Mg, Al, K, Na, Ca, Si, Ti, Sn, V, Ge, Ga, B, As, Zr, Mn and Cr, and the at least one element M1 is provided on a surface of the positive electrode active material particles. An atomic ratio of a total amount of the at least one element M1 to an amount of Co on the surface of the positive electrode active material particles is from 0.6 to 1.3.

Abstract: A positive electrode active material includes powder of composite particles including a lithium transition metal composite oxide having a lamellar rock-salt structure and a spinel phase. The spinel phase includes an oxide including lithium and at least a first element X1 selected from the group consisting of magnesium, aluminum, titanium, manganese, yttrium, zirconium, molybdenum, and tungsten, and the lithium transition metal composite oxide includes nickel or cobalt and the first element X1.

Abstract: A positive electrode active material includes secondary particles obtained by aggregation of a plurality of primary particles. The primary particles include, core particles including a lithium composite oxide, and a layer that is provided on surfaces of the core particles and includes a lithium composite oxide. The lithium composite oxide included in the core particles and the lithium composite oxide included in the layer have the same composition or almost the same composition, and crystallinity of the lithium composite oxide included in the layer is lower than crystallinity of the lithium composite oxide included in the core particles.

Abstract: A positive electrode active material includes: a composite particle that includes a particle containing a lithium transition metal composite oxide of Li and Co and a layer that is provided on a surface of the particle and includes an oxide of Li, Ni and Mn. Ni and Mn have a concentration distribution centered on the center from a surface of the composite particle, in a depth range in which a ratio d (%) satisfies 0.04%?d?0.20%, a mole fraction rn of Ni and a mole fraction rm of Mn are within ranges of 0.05?rn and 0.05?rm, respectively, and a ratio rn2/rn1 and a ratio rm2/rm1 are within ranges of 0.85?rn2/rn1?1.0 and 0.85?rm2/rm1?1.0, respectively.

Abstract: A positive electrode active material includes: a particle including a lithium composite oxide; a first layer that is provided on a surface of the particle and includes a lithium composite oxide; and a second layer that is provided on a surface of the first layer. The lithium composite oxide included in the particle and the lithium composite oxide included in the first layer have the same composition or almost the same composition, the second layer includes an oxide or a fluoride, and the lithium composite oxide included in the first layer has lower crystallinity than the lithium composite oxide included in the particle.

Abstract: A secondary battery includes a positive electrode including a positive electrode active material which includes a center portion including a lithium composite oxide including cobalt and an element M, and a covering portion that is provided on at least a portion of a surface of the center portion and contains lithium, nickel, and manganese elements. A concentration thereof has a gradient in a direction from a surface toward a center of the positive electrode active material. A first molar fraction satisfies 0.03<R<0.13 at a first position within the covering portion where the proportion D satisfies D=0.05. A second molar fraction satisfies 0.01<R<0.13 at a second position within the center portion where the proportion D satisfies D=0.3. A ratio F of the second molar fraction to the first molar fraction satisfies 0.7?F?1.

Abstract: A secondary battery includes a positive electrode including a positive electrode active material which includes a center portion including a lithium composite oxide including cobalt and an element M, and a covering portion that is provided on at least a portion of a surface of the center portion and contains lithium, nickel, and manganese elements. A concentration thereof has a gradient in a direction from a surface toward a center of the positive electrode active material. A first molar fraction satisfies 0.03<R<0.13 at a first position within the covering portion where the proportion D satisfies D=0.05. A second molar fraction satisfies 0.01<R<0.13 at a second position within the center portion where the proportion D satisfies D=0.3. A ratio F of the second molar fraction to the first molar fraction satisfies 0.7?F?1.

Abstract: A secondary battery includes: a cathode including an active material; an anode; and an electrolytic solution, and the active material includes a plurality of active material particles as primary particles and a carbon material. The active material particles contain a polyanion-based compound. The carbon material contains a first carbon material present on surfaces of the active material particles, and a second carbon material present between the active material particles provided with the first carbon material. A ratio B/A between a total carbon amount A and a surface carbon amount B of the active material satisfies 7<B/A<11.5. A ratio D/C between a specific surface area C of the active material, and an oil feed amount D of N-methyl-2-pyrrolidone satisfies 1.5<D/C?2.

Abstract: A positive electrode active material includes: a particle including a lithium composite oxide; a first layer that is provided on a surface of the particle and includes a lithium composite oxide; and a second layer that is provided on a surface of the first layer. The lithium composite oxide included in the particle and the lithium composite oxide included in the first layer have the same composition or almost the same composition, the second layer includes an oxide or a fluoride, and the lithium composite oxide included in the first layer has lower crystallinity than the lithium composite oxide included in the particle.

Abstract: A positive electrode active material includes: secondary particles obtained by aggregation of a plurality of primary particles. The primary particles include, core particles including a lithium composite oxide, and a layer that is provided on surfaces of the core particles and includes a lithium composite oxide. The lithium composite oxide included in the core particles and the lithium composite oxide included in the layer have the same composition or almost the same composition, and crystallinity of the lithium composite oxide included in the layer is lower than crystallinity of the lithium composite oxide included in the core particles.

Abstract: A positive electrode active material includes: a composite particle that includes a particle containing a lithium transition metal composite oxide of Li and Co and a layer that is provided on a surface of the particle and includes an oxide of Li, Ni and Mn. Ni and Mn have a concentration distribution centered on the center from a surface of the composite particle, in a depth range in which a ratio d (%) satisfies 0.04%?d?0.20%, a mole fraction rn of Ni and a mole fraction rm of Mn are within ranges of 0.05?rn and 0.05?rm, respectively, and a ratio rn2/rn1 and a ratio rm2/rm1 are within ranges of 0.85?rn2/rn1?1.0 and 0.85?rm2/rm1?1.0, respectively.

Abstract: A secondary battery includes: a cathode including a cathode active material layer on a cathode current collector; an anode; and an electrolytic solution. The cathode active material layer includes spherical active materials each being a secondary particle and planular active materials each being a secondary particle. The spherical active materials are each included in a region closer to the cathode current collector, and the planular active materials are each included in a region farther from the cathode current collector. Primary particles of the spherical active materials have an average particle diameter that is larger than an average particle diameter of primary particles of the planular active materials.

Abstract: A secondary battery includes: a cathode including an active material; an anode; and an electrolytic solution, and the active material includes a plurality of active material particles as primary particles and a carbon material. The active material particles contain a polyanion-based compound. The carbon material contains a first carbon material present on surfaces of the active material particles, and a second carbon material present between the active material particles provided with the first carbon material. A ratio B/A between a total carbon amount A and a surface carbon amount B of the active material satisfies 7<B/A<11.5. A ratio D/C between a specific surface area C of the active material, and an oil feed amount D of N-methyl-2-pyrrolidone satisfies 1.5<D/C?2.