FINE POROUS POLYOLEFIN SEPARATOR FOR SECONDARY BATTERY AND ITS MANUFACTURING METHOD

摘要

A fine porous polyolefin separator for a secondary battery is provided to improve a charge and discharge efficiency of a secondary battery and increase a battery life by preventing the formation of dendrite around a cathode. The fine porous polyolefin separator for a secondary battery comprises a cathode-side surface layer and an anode-side surface layer. The cathode-side surface layer includes 90-97wt% of pores having a pore size of 80nm-2mum. The anode-side surface layer includes 90-97wt% of pores having a pore size of 30nm-1mum. The thickness of the cathode-side surface layer is thicker than that of the anode-side surface layer by about 20-30%.