A sodium-ion battery cell, a secondary battery, and an electric device are provided. The sodium-ion battery cell includes a cylindrical casing defining an accommodating cavity and an electrode assembly disposed within the accommodating cavity. The electrode assembly includes a negative electrode sheet comprising a negative electrode current collector and a negative electrode active layer disposed on at least one surface of the negative electrode current collector. The negative electrode current collector has a density less than or equal to 5.0 g/cm3. A group margin of the sodium-ion battery cell satisfies 0.95≤group margin<1, where the group margin is a ratio of a diameter of the electrode assembly to a diameter of the accommodating cavity.