Abstract: Provided are a positive electrode material and a preparation method thereof, a composite positive electrode material, a positive electrode plate, and a secondary battery. The positive electrode material includes: a core, a first shell layer, and a second shell layer. The first shell layer wraps around a surface of the core. The second shell layer wraps around a surface of the first shell layer. The core includes a lithium manganese iron phosphate material. The first shell layer includes a polyanionic positive electrode material. The polyanionic positive electrode material contains no manganese. The second shell layer includes a hydrophobic conductive material. When ensuring a relatively high energy density of the lithium manganese iron phosphate material, the positive electrode material improves the electrical conductivity of the lithium manganese iron phosphate material, alleviates the problem of hygroscopicity, and reduces manganese dissolution during cycling.

Abstract: Embodiments of the present application provide a charging control method and a charging control apparatus of a lithium-ion battery. The charging control method includes: performing charging control on the lithium-ion battery for the ith time, so that a battery capacity value of the lithium-ion battery at a target charging cut-off voltage is 0.95C0 to 1.05C0, where C0 is a nominal capacity of the lithium-ion battery, and the target charging cut-off voltage is less than or equal to the nominal voltage of the lithium-ion battery. The charging control method and the charging control apparatus according to the embodiments of the present application are beneficial to keeping the quantity of active lithium unchanged, thereby achieving the effect of automatically supplementing the battery capacity along with aging.

Abstract: A positive electrode active material includes a low-to-medium nickel ternary material and a high-lattice-volume-change positive electrode material. The low-to-medium nickel ternary material has a mass ratio W1?45% in the positive electrode active material. The high-lattice-volume-change positive electrode material satisfies: the thickness change rate of the positive electrode active substance layer is ?2.6%, and the thickness change rate is (H1?H2)/H1, where H1 is the fully discharged thickness of the positive electrode active substance layer, and H2 is the fully charged thickness of the positive electrode active substance layer.

Abstract: A battery unit may comprise a first cell type and a second cell type electrically connected at least in series, wherein the first cell type may include N first cells, the second cell type may include M second cells, and N and M are positive integers; the first cell may have a discharge cell balance rate of CB1, the second cell may have a discharge cell balance rate of CB2, with 0.5?CB1?CB2?1.4, and when the battery unit is charged to 95%-100% of the state of charge, the first cell may have a corresponding open-circuit voltage change rate of not greater than 0.005 V/% SOC, and the second cell type may have a corresponding open-circuit voltage change rate greater than that of the first cell.

Abstract: A positive electrode active material comprising an A material and a B material, wherein the A material is at least one selected from the following single crystal materials or single crystal-like materials: LixMy(PO4)z, wherein M is selected from one or more of Ni, Co, Mn, Fe, Mg, Al, V, Zn, Zr, and F, v is the valence of M, 1?x?3, 1?z?3, and x+vy-3z=0; the A material has a Dv50 of 0.8 µm to 4.2 µm; the B material is selected from at least one of the following materials: (i) LiAO2, wherein A is Ni, Co or Mn; or (ii) LiNiaCobE1-a-bO2, wherein E is selected from at least one of Mn and Al, 0.50?a?0.98, and 0.001?b?0.3; wherein based on the total weight of the positive electrode active material, the A material is present in a mixing ratio m of 50 wt% to 97 wt%.

Abstract: A battery unit may comprise a first cell type and a second cell type electrically connected at least in series, wherein the first cell type may include N first cells, the second cell type may include M second cells, and N and M are positive integers; the first cell may have a discharge cell balance rate of CB1, the second cell may have a discharge cell balance rate of CB2, with 0.5?CB1?CB2?1.4, and when the battery unit is charged to 95%-100% of the state of charge, the first cell may have a corresponding open-circuit voltage change rate of not greater than 0.005 V/% SOC, and the second cell type may have a corresponding open-circuit voltage change rate greater than that of the first cell.

Abstract: The present disclosure provides an array substrate, a display panel, and a display device. The array substrate includes a substrate, pixel units arranged in rows and columns on the substrate, and data lines between at least some columns of pixel units. Two columns of pixel units are disposed between two adjacent data lines. Each of the pixel units includes a first electrode including a planar electrode and a second electrode including a slit electrode having at least one slit, sequentially disposed on the substrate. The slit electrode of each of the pixel units has a first side proximal to a data line nearest to the slit electrode and a second side distal to the data line nearest to the slit electrode, opposite to each other in a row direction. The slit electrode of at least one of the pixel units includes at least one opening on the first side.