Abstract: This application relates to a secondary battery and an apparatus including the secondary battery. Specifically, the secondary battery of this application includes a negative electrode plate, where the negative electrode plate includes a negative current collector and negative film layers where the negative film layers include a first negative film layer and a second negative film layer, the first negative film layer is disposed on at least one surface of the negative current collector and includes a first negative active material, and the second negative film layer is disposed on the first negative film layer and includes a second negative active material; the first negative active material includes natural graphite, and the second negative active material includes artificial graphite; the first negative active material satisfies 4.0?COI1?7.0; and the second negative active material satisfies 2.2?COI2?4.2.

Abstract: A negative electrode active material includes a carbon-silicon composite, which includes a carbon-based particle and a silicon nanoparticle. The carbon-based particle has a carbon skeleton. The silicon nanoparticle is attach to the carbon skeleton of carbon-based particle. In a peripheral area of the carbon-silicon composite, a mass percentage content A1 of carbon element and a mass percentage content B1 of silicon element satisfy 0.8?B1/A1?2.5.

Abstract: The present application discloses a negative electrode active material and a method for preparing the same, a secondary battery, and an apparatus including the secondary battery. The negative electrode active material includes a core and a coating layer covering the surface of the core, the core includes artificial graphite, the coating layer includes amorphous carbon, and the particle size uniformity of the negative electrode active material is from 0.25 to 0.45.

Abstract: The present application relates to a secondary battery, a process for preparing the same and an apparatus containing the secondary battery.

Abstract: Disclosed herein is a medical system (100, 300) comprising a memory (110) storing machine executable instructions (120) and a convolutional neural network (122). The convolutional neural network is configured to receive as input a complex array (128) encoding a selection of at least one excitation field of view (324, 900) and in response output a radio frequency wave form (130) and multiple spatially selective gradient pulse waveforms (132). The convolutional neural network is a multi-task convolutional neural network.

Abstract: A negative-electrode active material includes a carbon matrix, boron, and iron distributed in an interior of the carbon matrix.

Abstract: An artificial graphite and preparation method thereof, negative electrode plates, secondary batteries, battery modules, battery packs, and electrical device are provided. In some embodiments, the artificial graphite has a particle size of Dv5016 ?m and an air oxidation peak temperature Tpeak of 830° C., wherein the air oxidation peak temperature Tpeak of artificial graphite refers to the highest peak temperature of a differential thermo-gravimetric analysis curve obtained when the artificial graphite is subjected to a thermo-gravimetric test having a weighing mass of 10±0.05 mg, with a purging gas of air, an airflow rate of 60 mL/min, and a heating rate of 5° C./min, in a test temperature range of 40° C. to 950° C. By the present application, the resulting secondary batteries have higher first-cycle Coulomb efficiency and longer cycle life under the premise of good fast charging performance.

Abstract: A negative electrode active material and a preparation method, a secondary battery, a battery module, a battery pack and an electrical apparatus are provided. The negative electrode active material comprises an inner core, an interlayer and an outer shell layer, wherein the interlayer is cladded on the surface of the inner core, and the outer shell layer is cladded on the surface of the interlayer; the inner core comprises silicon, an oxide of silicon and lithium silicate; the interlayer comprises silicon, or silicon and lithium silicate; and the outer shell layer comprises amorphous carbon. An inner core comprising silicon, an oxide of silicon and lithium silicate is used as a nucleus, and an interlayer containing silicon as well as an outer shell layer comprising amorphous carbon are cladded outwards in sequence to form a uniformly cladded and structurally stable negative electrode active material with a core-shell structure.

Abstract: This application relates to a secondary battery, a process for preparing the same and an apparatus containing the secondary battery. In particular, the negative electrode plate comprises a negative current collector and a negative electrode film, wherein the negative electrode film comprises a first negative electrode film and a second negative electrode film, the first negative electrode film is comprises a first negative electrode active material, and the particle size uniformity of the first negative electrode active material is from 0.4 to 0.6; the second negative electrode film comprises a second negative electrode active material, and the particle size uniformity of the second negative electrode active material is from 0.25 to 0.45, and a ratio of the particle size uniformity of the first negative electrode active material to the particle size uniformity of the second negative electrode active material is from 1.05 to 1.9.

Abstract: A negative electrode plate, a secondary battery, a battery module, a battery pack, and an electrical device are provided. The negative electrode plate includes a negative current collector and a negative film layer disposed on the negative current collector. The negative film layer includes a first negative film layer and a second negative film layer. The second negative film layer is located between the negative current collector and the first negative film layer. The second negative film layer includes a metal element M, and an atomic radius rM of M and an atomic radius rLi of Li satisfy 0 < ? "\[LeftBracketingBar]" r M - r Li r Li ? "\[RightBracketingBar]" × 100 ? % ? 12 ? % . This application can effectively suppress precipitation of lithium metal on the surface of the negative electrode plate, and significantly improve kinetic performance, cycle performance, and safety performance of the secondary battery.

Abstract: The present application provides a secondary battery including a negative electrode sheet, and the negative electrode sheet includes: a negative electrode current collector; a first negative film layer provided on at least one surface of the negative electrode current collector; and a second negative film layer provided on a surface of the first negative film layer; where the first negative film layer includes a first negative active material and a first conductive agent, and the first negative active material includes a silicon-based material; and a mass proportion of the silicon-based material in the first negative film layer is greater than or equal to 30%, and a mass proportion of the first conductive agent in the first negative film layer is greater than or equal to 25%. A battery cell of the secondary battery of the present application does not easily expand and has good cycle performance.

Abstract: Embodiments provide a secondary battery and an apparatus containing the secondary battery. The secondary battery includes a negative electrode plate. The negative electrode plate includes a copper-based current collector and a negative electrode film layer disposed on at least one surface of the copper-based current collector and including a negative electrode active material, and the negative electrode active material includes graphite. The negative electrode plate satisfies Tx?25, where Tx is as defined in the specification.

Abstract: Embodiments provide a secondary battery and a preparation method thereof, and a battery module, battery pack, and apparatus containing such secondary battery. In those embodiments, a negative electrode plate includes a negative-electrode current collector and a negative-electrode film layer that is disposed on at least one surface of the negative-electrode current collector and that includes a negative-electrode active material. The negative-electrode active material contains graphite, and the negative electrode plate satisfies that, when the negative electrode plate and a lithium metal sheet constitute a button battery which is discharged to 5.0 mV at 0.05 C, a capacity increment curve V-dQ/dV of the button battery has a third-order lithiation phase transition peak of graphite at position 0.055V-0.085V.

Abstract: A negative electrode sheet includes a current collector, and a first active material layer and a second active material layer that are sequentially provided on at least one surface of the current collector. The first active material layer includes a first negative electrode active material. Particle sizes of the first negative electrode active material satisfy: 0.02?A1=(Dn10)1/(Dv50)1?0.2. The second active material layer includes a second negative electrode active material. Particle sizes of the second negative electrode active material satisfy: 0.02?A2=(Dn10)2/(Dv50)2?0.3; and A1 and A2 satisfy 1<A2/A1<2.5.

Abstract: This application relates to a secondary battery, a process for preparing the same and an apparatus containing the secondary battery. In particular, the negative electrode plate comprises a negative current collector and a negative electrode film, wherein the negative electrode film comprises a first negative electrode film and a second negative electrode film, the first negative electrode film is disposed on at least one surface of the negative current collector and comprises a first negative electrode active material, the first negative electrode active material comprises graphite, and the particle size uniformity of the first negative electrode active material is from 0.4 to 0.6; the second negative electrode film is disposed on the first negative electrode film and comprises a second negative electrode active material, the second negative electrode active material comprises artificial graphite, and the particle size uniformity of the second negative electrode active material is from 0.25 to 0.45.

Abstract: An artificial graphite satisfies: PD5 t/PD0.5 t ? 1.35, where PDst is a compacted density of the artificial graphite measured under a pressure of 5 ton, and PD0.5 t is a compacted density of the artificial graphite measured under a pressure of 0.5 ton.

Abstract: The present application discloses a negative electrode active material and a method for preparation thereof, a secondary battery, and an apparatus including the secondary battery. The negative electrode active material includes a core and a coating layer covering a surface of the core, the core includes artificial graphite, the coating layer includes amorphous carbon, the negative electrode active material has a surface area average particle size D(3,2) denoted as A, the negative electrode active material has a surface area average particle size D(3,2) denoted as B after powder compaction under a pressure of 20 kN, and the negative electrode active material satisfies: 72%?B/A×100%?82%.

Abstract: A negative electrode sheet includes a current collector, and a first active material layer and a second active material layer that are sequentially provided on at least one surface of the current collector. The first active material layer includes a first negative electrode active material. Particle sizes of the first negative electrode active material satisfy: 0.02?A1=(Dn10)1/(Dv50)1?0.2. The second active material layer includes a second negative electrode active material. Particle sizes of the second negative electrode active material satisfy: 0.02?A2=(Dn10)2/(Dv50)2?0.3; and A1 and A2 satisfy 1<A2/A1<2.5.

Abstract: Embodiments provide a secondary battery and a preparation method thereof, and a battery module, battery pack, and apparatus containing such secondary battery. In those embodiments, a negative electrode plate includes a negative-electrode current collector and a negative-electrode film layer that is disposed on at least one surface of the negative-electrode current collector and that includes a negative-electrode active material. The negative-electrode active material contains graphite, and the negative electrode plate satisfies that, when the negative electrode plate and a lithium metal sheet constitute a button battery which is discharged to 5.0 mV at 0.05C, a capacity increment curve V-dQ/dV of the button battery has a third-order lithiation phase transition peak of graphite at position 0.055V-0.085V.

Abstract: Embodiments provide a secondary battery and an apparatus containing the secondary battery. The secondary battery includes a negative electrode plate. The negative electrode plate includes a copper-based current collector and a negative electrode film layer disposed on at least one surface of the copper-based current collector and including a negative electrode active material, and the negative electrode active material includes graphite. The negative electrode plate satisfies Tx?25, where Tx is as defined in the specification.