Patent ID: 8870978

Claim:
A method for manufacturing a jelly-roll type electrode assembly having a cathode/separation membrane/anode laminate structure, including: (a) coating both sides of a porous substrate with organic/inorganic composite layers, each of which includes inorganic particles and an organic polymer as a binder, so as to fabricate a composite membrane; and (b) inserting one end of a sheet laminate comprising a cathode sheet and an anode sheet as well as the composite membrane into a mandrel, winding the sheet laminate around the mandrel, and then, removing the mandrel, wherein at least one of the organic/inorganic composite layers includes microfine pores capable of moderating a variation in volume during charge/discharge of a secondary battery, and an interfacial friction coefficient between the composite membrane and the mandrel is not more than 0.28, wherein the composite membrane is formed by a process including: (i) dissolving an organic polymer, which is capable of inducing a binding force between inorganic particles and adhesion of the inorganic particles to a surface of a substrate, in a solvent (‘first solvent’) to prepare a solution; (ii) adding the inorganic particles to the prepared solution to prepare an organic/inorganic coating solution; (iii) immersing a porous substrate in the coating solution through dip-coating, so as to form coating layers on both sides of the porous substrate; and (iv) removing the solvent to produce an organic/inorganic composite layer having microfine pores, and wherein the inorganic particle in step (ii) is added to the prepared solution after being dispersed in a second solvent.