Abstract: This application relates to an electrode plate structure. With a ratio CB1 of a surface loading of a second cathode material layer to a surface loading of a first anode material layer controlled to be 1:(1.01-1.3) and a ratio CB2 of a surface loading of a first cathode material layer to a surface loading of a second anode material layer controlled to be 1:(1.03-1.4), the surface loadings of the first anode material layer and second anode material layer are slightly higher than the surface loadings of the corresponding second cathode material layer and first cathode material layer, so that during cycling, especially at a high rate, the first anode material layer and the second anode material layer can provide sufficient lithiation capacity, avoiding lithium precipitation on the anode. This application also implements a differential design for the material layers on two sides of the electrode plates.

Abstract: A film preparation apparatus includes a single-screw machine and an extrusion die. The single-screw machine is configured for conveying and extruding an active material mixture, and the extrusion die is connected with a discharge end of the single-screw machine and configured for extruding out an active material film. A screw of the single-screw machine includes a compression section, an axial length of the compression section is L1, an axial length of the screw is L, and 0.45?L1/L?0.65.

Abstract: Provided are a secondary battery including an electrode sheet, the electrode sheet including: a current collector and an active material layer; the active material layer is provided on at least one surface of the current collector; the active material layer is divided into a first region and a second region in its thickness direction; the first region is located in a direction close to the surface of the current collector, the thickness of the first region accounts for ½ of the thickness of the active material layer, the binder content in the first region is denoted as A; the second region is located in a direction away from the surface of the current collector, the thickness of the second region accounts for ½ of the thickness of the active material layer, and the binder content in the second region is denoted as B; the electrode sheet satisfies: 1<B/A?1.04.

Abstract: A secondary battery is disclosed. The secondary battery includes a first binder and a second binder, the first binder includes at least one of polyvinylidene fluoride, rubber, epoxy resin, polyurethane, and acrylate, and the second binder includes at least one of polytetrafluoroethylene, polyimide, polypropylene, polyethylene, ethylene vinyl acetate copolymer, and styrene-ethylene-butylene-styrene block copolymer.

Abstract: A drying apparatus for drying a material belt includes at least one material-belt turning mechanism, used for changing a travel direction of the material belt, and including a first passing roller, a turning roller, and a second passing roller sequentially arranged in the travel direction of the material belt. The turning roller is configured to move in a first direction relative to the first passing roller and the second passing roller to adjust a wrap angle of the material belt on the turning roller, the first direction perpendicular to an axial direction of the turning roller.

Abstract: Provided are an apparatus, process, and roller for forming electrode plate. The apparatus for forming electrode plate includes a first roller and a second roller. An inner cavity of a cylinder of the first roller is provided with a gas outlet structure, the gas outlet structure is connected to a gas supply apparatus, and surface of the cylinder of the first roller is provided with a circumferentially distributed cylinder gas discharge structure. The second roller is disposed opposite the first roller, and a gap is provided between the first roller and the second roller for rolling an electrode material into an electrode film.

Abstract: Embodiments of the present application provide a negative electrode plate, a secondary battery, a battery module, a battery pack and an electrical device. The negative electrode plate may comprise a negative electrode current collector; and a negative electrode active material layer, wherein the negative electrode active material layer may be disposed on at least one surface of the negative electrode current collector, and comprise, based on total weight of the negative electrode active material layer, 90.0% to 98.6% by weight of a negative electrode active material; 1.0%-5.0% by weight of a polymer binder; and 0.2%-4.0% by weight of a toughening fiber.

Abstract: A binder includes a polymer obtained by polymerizing at least a first component, a second component, and a third component. The first component includes a flexible monomer selected from C4-18 alkene. The second component includes a rigid monomer including at least one of an alkene having a rigid group or a polymerized monomer having a strong polar group. The rigid group is selected from C5-20 aryl, C4-8 saturated or unsaturated ring group, and C5-30 heterocyclyl. The third component includes a hydrophilic monomer containing a hydrophilic group selected from carboxyl, hydroxyl, amine, aldehyde, alcohol, amino, and amido.