Battery cell, battery module and battery pack

The invention discloses a battery cell, a battery module and a battery pack, and relates to the technical field of batteries. The battery cell comprises a shell, a roll core and an electrolyte, the roll core and the electrolyte are arranged in the shell, and the roll core is formed by laminating or winding a positive plate, an isolating membrane and a negative plate which are arranged in a laminated manner; the positive plate comprises a positive current collector and a positive active material, the negative plate comprises a negative current collector and a negative active material, at least one of the positive current collector and the negative current collector is a composite current collector, the composite current collector comprises an insulating support layer and a conductive layer at least arranged on one side of the insulating support layer, the thickness of the insulating support layer is A, the thickness of a positive electrode active material layer formed after the positive electrode current colle