BATTERY CELL SUITABLE FOR SECONDARY BATTERY, AND SECONDARY BATTERY USING SAME

A battery cell, applicable to a secondary battery, includes at least one composite electrode unit; the composite electrode unit includes a positive electrode sheet and a negative electrode sheet; the positive electrode sheet includes a first positive active coating (4), the negative electrode sheet includes a first negative active coating (2), and the first positive active coating (4) and the first negative active coating (2) are stacked with an isolation coating (3) therebetween; a length and a width of the first negative active coating (2) are respectively greater than a length and a width of the first positive active coating (4); the isolation coating (3) includes an inorganic material and a polymer, a proportion of the inorganic material in the isolation coating (3) is not less than 70 wt%, a dielectric constant of the inorganic material is not less than 8, and an average particle size D50 of the inorganic material ranges from 0.2 µm to 5 µm.