Insulating film, battery cell, battery, and electric device

The utility model discloses an insulating film, a battery monomer, a battery and a power utilization device, the insulating film comprises a bottom and a plurality of side walls, one end of each side wall is connected with the bottom, one side, far away from the bottom, of at least one side wall is provided with a thickening area, and a plurality of liquid storage holes are formed in the thickening area. The thickened area is arranged to wrap the thinned part of the top of the bare cell, and the electrolyte stored in the liquid storage hole can be extruded out when the bare cell is expanded in the use process, so that electrolyte infiltration of a pole piece at the top of the bare cell is improved, and the condition of lithium precipitation is prevented.