Preparation process for preventing deformation of jelly-roll type electrode assembly

An organic/inorganic composite membrane for a secondary battery prepared by the method comprising:

• (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 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 membrane having microfine pores,
• wherein the organic/inorganic composite membrane includes microfine pores capable of moderating a variation in volume during charge/discharge of the secondary battery, and the interfacial friction coefficient (μ) between the composite membrane and a mandrel used for manufacturing a jelly-roll type electrode assembly is not more than 0.28.