ELECTRODE ASSEMBLY AND LITHIUM ION BATTERY

The present invention provides an electrode assembly and a lithium-ion battery. The electrode assembly includes a positive electrode plate, a separator, and a negative electrode plate, where the negative electrode plate includes a negative electrode current collector and a negative electrode active substance layer, the negative electrode plate further includes a lithium metal layer, the lithium metal layer is formed by a plurality of regular or irregular strip-shaped lithium-rich regions, and the plurality of lithium-rich regions present a discontinuous pattern of spaced distribution in a length direction of the negative electrode plate. The electrode assembly further satisfies that: negative electrode capacity per unit area/positive electrode capacity per unit area = 1.2 to 2.1 and negative electrode capacity per unit area/(positive electrode capacity per unit area + capacity of the lithium metal layer on the surface of the negative electrode active substance layer per unit area × 80%) ≥ 1.10. The lithium-ion battery of the present invention has relatively high lithium replenishment efficiency and relatively low direct current impedance, as well as long cycle life and storage life.