Abstract: A secondary battery and an electric apparatus are disclosed. The secondary battery includes a negative electrode plate including a negative electrode current collector and a negative electrode film layer with a thickness of H; a first surface away from the negative electrode current collector; and a second surface opposite the first surface. A first region of the negative electrode film layer includes a first active material with a thickness range from the second surface of the negative electrode film layer to 0.3H. The first active material includes a first carbon-based material and a first silicon-based material. The first carbon-based material includes primary particles. The first silicon-based material includes secondary particles formed by aggregating the primary particles. A second region of the negative electrode film layer includes a second active material and has a thickness range from the first surface of the negative electrode film layer to 0.3H.

Abstract: A secondary battery and an electric apparatus are disclosed. The secondary battery includes a negative electrode plate including a negative electrode current collector and a negative electrode film layer with a thickness of H; a first surface away from the negative electrode current collector; and a second surface opposite the first surface. A first region of the negative electrode film layer includes a first active material with a thickness range from the second surface of the negative electrode film layer to 0.3H. The first active material comprises a first silicon-based material, which comprises secondary particles formed by aggregation of primary particles. A second region of the negative electrode film layer comprises a second active material with a thickness range from the first surface of the negative electrode film layer to 0.3H.

Abstract: The present application relates to a silicon-carbon composite material in the form of particles comprising a porous carbon skeleton, a silicon-containing deposition layer, and a carbon-containing coating layer, wherein the silicon-containing deposition layer is in pores of the porous carbon skeleton, the carbon-containing coating layer is on the silicon-containing deposition layer and/or on the surface of the particles, and the silicon-carbon composite material has an oil absorption number of 35 mL/100 g to 80 mL/100 g. The silicon-carbon composite material of the present application has a high energy density and an improved cycle life. In addition, the present application further relates to a negative electrode plate comprising the material, a secondary battery, a battery module, a battery pack, and a power consuming device.

Abstract: A silicon carbon negative material is provided. The silicon carbon negative material includes a porous carbon base, nano-silicon crystal grains located in pores of the porous carbon base, and a carbon coating layer located on a surface of the porous carbon base. The nano-silicon crystal grains include an elemental silicon core and a LixSiy coating layer, x is an integer selected from 7 to 22, and y is an integer selected from 3 to 7.

Abstract: This application relates to a silicon-carbon composite material. The silicon-carbon composite material includes a carbon nanotube-and-porous carbon composite substrate and a silicon-based material. The porous carbon is connected to the carbon nanotube by a connecting unit in the carbon nanotube-and-porous carbon composite substrate. The high conductivity and strong mechanical properties of the carbon nanotubes can improve the overall conductivity, compression resistance, and expansion resistance of the silicon-carbon composite material, thereby improving cycle performance, electrode plate cycle expansion resistance, and rate performance of a secondary battery.

Abstract: A silicon-carbon composite material and a preparation method thereof, a negative electrode plate, and a secondary battery are disclosed. The silicon-carbon composite material includes a porous carbon matrix and silicon-based particles. The porous carbon matrix internally includes a plurality of pore channels with a width of 5 nm-50 nm. The silicon-based particles are distributed in the pore channels, and the porous carbon matrix meets: 1.0×10?7?Vtotal/Stotal?10.0×10?7, where Stotal is the total surface area occupied by the pore channels with the width of 5 nm-50 nm, and the measurement unit is: ×104 cm2/g; and Vtotal is the total pore volume occupied by the pore channels with the width of 5 nm-50 nm. The silicon-carbon composite material has high electrical conductivity. When being applied to a negative electrode of the secondary battery, the silicon-carbon composite material can effectively increase the volume capacity and energy density of the secondary battery.

Abstract: The present application provides a silicon-carbon composite, a method of preparing the same, and a secondary battery including the silicon-carbon composite. The silicon-carbon composite includes porous carbon-based matrix particles having a three-dimensional network interconnecting pore structure; and silicon-based nanoparticles, at least a portion of which is provided in the three-dimensional network interconnecting pore structure. The present application enables secondary batteries to have an improved cycle performance and energy density.

Abstract: The present disclosure provides a secondary battery including a negative electrode sheet. 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. 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. 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%. The secondary battery of the present disclosure does not easily expand and has good cycle performance.

Abstract: The present disclosure provides a secondary battery including a negative electrode plate, and the negative electrode plate includes: a negative electrode current collector, a first negative electrode active material layer, and a second negative electrode active material layer. The first negative electrode active material layer is arranged on at least one surface of the negative electrode current collector, and the first negative electrode active material layer includes a silicon-based material and a porous material; and the second negative electrode active material layer is arranged on a surface of the first negative electrode active material layer away from the negative electrode current collector.

Abstract: Provided are a negative electrode active material and a preparation method thereof, a secondary battery, and an electric apparatus. The negative electrode active material includes: a core material; and a first coating layer provided on at least part of a surface of the core material, where the first coating layer includes a porous carbon material and nano silicon-based particles, and the nano silicon-based particles are embedded into pore structures of the porous carbon material.

Abstract: A silicon carbon composite material includes a carbon matrix and a silicon material, the carbon matrix has a cross-linked porous structure internally, and the silicon material is at least partially distributed in the cross-linked porous structure. A value of flexibility C1 of the silicon carbon composite material satisfies 0.4?C1?2. C1 is a factor by which a compression deformation variable of the silicon carbon composite material is scaled to be equal to its rebound deformation variable, representing flexibility of the silicon carbon composite material. When the C1 value satisfies 0.4?C1?2, the silicon carbon composite material has good flexibility, reducing overall impact of expansion stress of silicon on the silicon carbon composite material, and allowing for a certain degree of contractility of the carbon matrix framework, so that residual stress can be received and released, thereby maintaining overall stability of the silicon carbon composite material.

Abstract: The present application provides a negative electrode active material, a secondary battery comprising the same and an electrical device, wherein the negative electrode active material comprises a matrix material and a silicon-based material, the matrix material comprises a plurality of pore structures, at least a part of the silicon-based material is located in pore structures of the matrix material, at least a part of the silicon-based material has a crystalline structure, the silicon-based material comprises a first silicon-based material and a second silicon-based material with different grain sizes, and a ratio of grain size of the first silicon-based material to grain size of the second silicon-based material is greater than or equal to 1.6. The negative electrode active material can result in a secondary battery having high energy density, high First Coulombic Efficiency, long cycle life and long storage life at the same time.

Abstract: Provided is a negative electrode plate, comprising: a negative electrode current collector and a first negative electrode active material layer. The first negative electrode active material layer is arranged on at least one surface of the negative electrode current collector, wherein, components of the first negative electrode active material layer comprise, by mass: 30%-70% of a silicon-based material, 15%-40% of a binder and 15%-40% of a conductive agent.

Abstract: The present application provides a negative electrode active material, a secondary battery comprising the same and an electrical device, wherein the negative electrode active material comprises a matrix material and a silicon-based material, the matrix material comprises a plurality of pore structures, at least a part of the silicon-based material is located in pore structures of the matrix material, the silicon-based material comprises a crystalline silicon-based material, a region formed by extending from outer surface of particle of the negative electrode active material to inside of the particle by a distance of 0.5 times a length between any point on the outer surface of the particle of the negative electrode active material and a core of the particle is recorded as an outer region, and a region inside the outer region is recorded as an inner region.

Abstract: A positive active material comprising active material bulk particles and a coating layer of an oxide containing N element is disclosed, wherein the surface of the active material bulk particle is doped with M element to form a doped layer, and the content of the M element is 400 ppm to 3000 ppm, and the content of the M element gradually decreases from the outer surface of active material bulk particles towards the core direction; wherein the content of the N element in the coating layer is 100 ppm to 2000 ppm; wherein the average content of the N element per unit volume of the coating layer is greater than the average content of the M element per unit volume of the doped layer; wherein the M element and the N element are each independently selected from one or more of Mg, Ca, Ce, Ti, Zr, Al, Zn, and B.

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: This application relates to a positive electrode active material and a preparation method thereof, a lithium-ion secondary battery and related battery module, battery pack, and apparatus. The positive electrode active material of this application includes a composite oxide of lithium, boron, and a transition metal element, where the transition metal element includes element nickel, and a molar ratio of element nickel to element lithium ranges from 0.55 to 0.95; the positive electrode active material includes secondary particles formed by primary particles; at least 50% of the primary particles in the secondary particle are arranged radially; in the outermost layer of the secondary particle, 70% or more of the primary particles each have at least two parallel sides; and in a cross section through the center of the secondary particle, 60% or more of the primary particles each have at least two parallel sides.

Abstract: A positive active material comprising active material bulk particles and a coating layer of an oxide containing N element is disclosed, wherein the surface of the active material bulk particle is doped with M element to form a doped layer, and the content of the M element is 400 ppm to 3000 ppm, and the content of the M element gradually decreases from the outer surface of active material bulk particles towards the core direction; wherein the content of the N element in the coating layer is 100 ppm to 2000 ppm; wherein the average content of the N element per unit volume of the coating layer is greater than the average content of the M element per unit volume of the doped layer; wherein the M element and the N element are each independently selected from one or more of Mg, Ca, Ce, Ti, Zr, Al, Zn, and B.

Abstract: The present invention relates to a reciprocating device for a power saw which includes a gear box, a main spindle, a rotary gear driven by the main spindle, a rotary transmission shaft fixed to the gear, a pair of support members and a reciprocating rod unit capable of moving reciprocatively, wherein the rotary transmission shaft and the main spindle are non-parallel to each other. The gear is arranged substantially between the pair of support members, thereby minimizing the space occupied by the internal structure of the reciprocating device and the weight of the power saw.