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

Abstract

Provided is a method for fabrication of 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 the organic/inorganic composite layer 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.

What is claimed is: 
     
         1 . 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.   
     
     
         2 . A jelly-roll type electrode assembly having a cathode/separation membrane/anode laminate structure prepared by the method comprising:
 (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 an organic/inorganic 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 an organic/inorganic composite layer, which includes microfine pores capable of moderating a variation in volume during charge/discharge of a secondary battery, is formed on both sides of the porous substrate and an interfacial friction coefficient between the composite membrane and the mandrel is not more than 0.28.   
     
     
         3 . A secondary battery comprising the jelly-roll type electrode assembly according to  claim 2  built in a battery case. 
     
     
         4 . The secondary battery according to  claim 3 , wherein the battery case is a pouch type case consisting of a laminate sheet comprising a resin layer and a metal layer.