Abstract: A secondary battery, a battery module, a battery pack, and an electrical device are provided. The secondary battery includes a negative electrode plate, a positive electrode plate, and a separator located between the negative electrode plate and the positive electrode plate. The negative electrode plate or the separator includes a safety coating. A negative electrode charge capacity Nc and a positive electrode charge capacity Pc of the secondary battery satisfy: 0.45?Nc/Pc<1, and/or, a negative electrode discharge capacity Nd and a positive electrode discharge capacity Pd of the secondary battery satisfy: 0.45?Nd/Pd<1. By setting the values of Nc/Pc and/or Nd/Pd and disposing the safety coating in the secondary battery, this application achieves good cycle performance and safety performance while maintaining a high energy density of the secondary battery.

Abstract: A secondary battery and an electric device are disclosed. The secondary battery includes a positive electrode sheet and a negative electrode sheet. The positive electrode sheet has a film layer comprising a positive electrode active material that contains transition metal elements, where nickel accounts for at least 85% of the total molar content of the transition metals. The energy per unit area of the positive electrode film layer on one side of the sheet ranges from 15 to 35 mWh/cm2. The negative electrode sheet includes a film layer with a carbon-silicon composite active material, in which silicon nanoparticles are attached to a carbon matrix having a carbon skeleton. The combination of a high-nickel positive electrode and a carbon-silicon composite negative electrode enhances the energy density of the secondary battery.

Abstract: A negative electrode plate comprises a negative electrode current collector and a negative electrode film layer located on at least one surface of the negative electrode current collector. The negative electrode film layer comprises a base coating and a negative electrode active layer. The base coating is located between the negative electrode current collector and the negative electrode active layer. The base coating comprises a conductive agent and a first binder. The negative electrode active layer comprises a silicon-based material. The tensile strength of the negative electrode current collector is ?800 MPa, and the peel strength of the negative electrode film layer is ?28 N/m.

Abstract: The present application relates to a battery electrode sheet and a manufacturing method therefor, a battery, and an electrical apparatus. The battery electrode sheet comprises a current collector and an active layer provided on the surface of the current collector; the component of the active layer comprises an active material; and the volume average particle size of the active material is D, the surface roughness Ra of the current collector is greater than or equal to 0.5 ?m, and the following relation is satisfied: Ra/D?0.15.

Abstract: A secondary battery, comprises at least two electrode plates, wherein at least one electrode plate comprises an intra-plate electrolyte, the intra-plate electrolyte comprises an intra-plate gel electrolyte and an intra-plate electrolytic solution, and the ratio RW of the mass of an electrolyte salt in the intra-plate gel electrolyte to the mass of an electrolyte salt in the intra-plate electrolytic solution satisfies 1<RW<9.

Abstract: A secondary battery and an electric device are disclosed. The secondary battery includes a positive electrode sheet and a negative electrode sheet. The positive electrode sheet has a film layer comprising a positive electrode active material that contains transition metal elements, where nickel accounts for at least 85% of the total molar content of the transition metals. The energy per unit area of the positive electrode film layer on one side of the sheet ranges from 15 to 35 mWh/cm2. The negative electrode sheet includes a film layer with a carbon-silicon composite active material, in which silicon nanoparticles are attached to a carbon matrix having a carbon skeleton. The combination of a high-nickel positive electrode and a carbon-silicon composite negative electrode enhances the energy density of the secondary battery.

Abstract: A battery cell, a battery, and an electric device are described. The battery cell includes a casing, an electrode assembly, and a support member. The casing is provided with an accommodation cavity. The electrode assembly is disposed in the accommodation cavity and includes a first electrode plate and a second electrode plate arranged according to a preset order in a first direction, the first electrode plate including a first portion overlapping the second electrode plate and a second portion extending beyond the second electrode plate. At least part of the support member is disposed between the electrode assembly and the casing in the first direction, a bending strength of the support member is greater than a bending strength of the first electrode plate, and a projection of the support member in the first direction covers a projection of the second portion in the first direction.

Abstract: An electrode sheet, a battery, and an electrical device are described. The electrode sheet comprises a current collector, an undercoat layer, and an active layer, and the undercoat layer is located between the current collector and the active layer, the undercoat layer comprises a conductive agent, the active layer comprises an active material and a first electrolyte absorption material, and the electrolyte absorption rate of the first electrolyte absorption material is greater than or equal to 110%.

Abstract: A secondary battery and a preparation method therefor, and an electric device are described. The secondary battery comprises a positive electrode sheet, a separator, a negative electrode sheet and an electrolyte, wherein the separator is arranged between the positive electrode sheet and the negative electrode sheet; the electrolyte comprises an electrolytic solution and a first gel electrolyte membrane; the first gel electrolyte membrane is arranged between the negative electrode sheet and the separator; a solidification ratio of the electrolyte is 60%-95%; the thickness of the first gel electrolyte membrane is a ?m; and the surface capacity of the negative electrode sheet is b mAh cm?2, and a/b is 0.1-1.5. The secondary battery of the present application not only has relatively good cycle performance, but also has a relatively high volume energy density.

Abstract: The positive electrode plate has a positive electrode active material, that includes LiaNixCoyMzO2, where 0.2?a?1.2, 0.85?x?1, 0?y<0.15, and x+y+z=1, and M includes one or more of Mn and Al; and a coating weight of the positive electrode active material is 19 mg/cm2 to 45 mg/cm2, and a compacted density is 3.2 g/cm3 to 3.8 g/cm3. The negative electrode plate has a negative electrode active material, where a mass percentage of a silicon-based material in the negative electrode active material is 20% to 100%, a coating weight of the negative electrode active material is 5 mg/cm2 to 13 mg/cm2, and a compacted density is 1.1 g/cm3 to 1.9 g/cm3; and an electrolyte, where an amount of the electrolyte is 0.8 g/Ah to 1.5 g/Ah, and includes an electrolytic solution, and an amount of the electrolytic solution outside a bare cell is less than or equal to 0.1 g/Ah.

Abstract: A gel electrolyte battery, comprising gel electrolytes, wherein the gel electrolytes comprise a first gel electrolyte and a second gel electrolyte, the first gel electrolyte is located in at least part of at least one side surface of at least one electrode sheet, and the second gel electrolyte is located in the direction of the first gel electrolyte distant from the electrode sheet. The electrode sheet is a positive electrode sheet or a negative electrode sheet.

Abstract: A negative electrode sheet, and a secondary battery and an electrical device including the same are described. The negative electrode sheet comprises a current collector and a negative electrode active layer stacked on surface of the current collector, and the negative electrode active layer comprises a first active layer and a second active layer which are stacked. The materials of the first active layer comprise, in percentage by mass based on the first active layer: 60%-94% of a silicon-based material, 0%-30% of a carbon-based material, and 5%-15% of a binder. The materials of the second active layer comprise, in percentage by mass based on the second active layer: 0%-5% of a second silicon-based material, 94%-99% of a second carbon-based material, and 1%-3% of a second binder. The negative electrode sheet has good cycle performance.

Abstract: A secondary battery and an electrical device are provided. The secondary battery includes a positive electrode sheet and a negative electrode sheet. The positive electrode sheet comprises a film layer that includes a positive electrode active material containing transition metals, with nickel accounting for at least 85% of the total molar content. The energy density of the positive electrode film layer on one side of the sheet ranges from 15 to 35 mWh/cm2. The negative electrode sheet comprises a film layer that includes a carbon-silicon composite, where silicon nanoparticles are attached to carbon matrix particles having a carbon skeleton. Through coordinated design of the positive and negative electrode materials, the energy density of the secondary battery is enhanced.

Abstract: A battery, the preparation of a battery, and a powered device are described. The battery includes a negative electrode plate that includes a negative electrode current collector and an active layer. The active layer is located on at least one surface of the negative electrode current collector. The active layer includes an active substance, a gel electrolyte, and a liquid electrolyte. An expansion rate of the negative electrode plate is greater than or equal to 10%. When the active substance expands during cycling, the gel electrolyte can stably fix the liquid electrolyte in the negative electrode plate, thereby reducing the risk of squeezing-induced leakage of a liquid electrolyte solution due to the expansion of the active substance. Thus, the negative electrode plate can maintain a relatively stable kinetic performance, thereby improving the cycling performance of the battery.

Abstract: A current collector, comprising a base layer, a first metal layer, and a second metal layer are disclosed. The first metal layer is disposed on at least one surface of the base layer; the second metal layer is disposed on the surface of the first metal layer facing away from the base layer; the first metal layer comprises elemental iron or an iron alloy; the second metal layer comprises at least one of a metal layer formed by any one of copper, tin, lead, molybdenum, chromium and nickel, an elemental metal stack formed by any two or more of the elements, and an alloy layer formed by any two or more of the elements. A preparation method for the current collector, and a secondary battery and an electric device are disclosed.

Abstract: Lithium replenishing spaces are disposed on a current collection structure, such that the lithium replenishing spaces communicate with an active layer on one side; and the battery is replenished with lithium by using lithium replenishing agents in the lithium replenishing spaces to offset an irreversible lithium consumption in a cycle process, so as to increase the total capacity and the energy density of the battery. According to the present application, due to average weights MA of corresponding active materials in different distribution regions on the active layer, a sum V0 of internal volumes of lithium replenishing spaces corresponding to each of the distribution regions is controlled in a positively correlated manner based on a change in the average weights of the active materials in the different distribution regions.

Abstract: Provided in the present application are a positive electrode active material, a preparation method, a positive electrode sheet, a secondary battery, and an electric device. The positive electrode active material has the following general formula: LiaNixM1yMnzM21-x-y-zO2, where M1 and M2 each independently include one or a plurality of Co, Al, B, Zr, Sr, Y, Sb, W, Ti, Mg, or Nb, 0.8?a?1.2, 0.55?x<1, 0<y?0.25, and 0?z?0.2, the positive electrode active material is present in a form of secondary particles formed by aggregation of primary particles, the secondary particles include secondary pores formed by spaces between the primary particles, and the secondary pores have an inner diameter of 0.1 ?m to 2 ?m.

Abstract: A battery cell comprises a negative electrode plate and an electrolyte, and the electrolyte comprises a solid electrolyte and a liquid electrolyte. The ratio of the thickness of the fully charged negative electrode plate to the thickness of the uncharged negative electrode plate is x, and the ratio of the mass of the solid electrolyte in the electrolyte to the mass of the electrolyte is y. When x?20%, 0<y?50%. When 20%<x<80%, 50%<y<90%. when x?80%, 90%?y?96%.

Abstract: The present application provides a positive electrode active material, a preparation method therefor, a secondary battery, and an electrical apparatus. The chemical formula of the positive electrode active material is LiaNixCoyM1?x?yO2, where M comprises one or more of Mn, Al, B, Zr, Sr, Y, Sb, W, Ti, Mg and Nb, 0.55?x?1.0, 0?y?0.45, 0.8?a?1.2, the positive electrode active material being a hollow structure, and the inner diameter d1 of the hollow structure being 0.3 ?m-5 ?m.

Abstract: A negative electrode material, a negative electrode plate, an electrode assembly, a battery, and an electrical device are disclosed. The negative electrode material includes a silicon-based material. The silicon-based material includes a porous silicon-based material and a micropowder silicon-based material configured to fill voids between particles of the porous silicon-based material. A volume median diameter of the porous silicon-based material is greater than a volume median diameter of the micropowder silicon-based material. The small-grained micropowder silicon-based material fills the voids between particles of the large-grained porous silicon-based material. The stress generated by the two types of silicon-based materials during intercalation and deintercalation of lithium is relieved by a pore channel structure in the porous silicon-based material and by an interstice between the porous silicon-based material and the micropowder silicon-based material.