Pouch type lithium secondary battery

Abstract

The present invention is related to a pouch type lithium secondary battery. The pouch type lithium secondary battery according to the present invention may comprise an electrode assembly including a positive electrode, a separator and a negative electrode, and a pouch having a groove for receiving the electrode assembly and upper and lower portions of which are fused to each other around the groove to form flange-shaped edges. In particular, the edges may be at least partially covered at ends thereof with insulating material. As a result, a short circuit between a metal foil of the pouch and the negative electrode of the battery can be prevented, and corrosion of the battery may be also prevented.

1 . A pouch type lithium secondary battery, comprising: 
 an electrode assembly comprising a positive electrode, a separator and a negative electrode; and    a pouch having a groove for receiving the electrode assembly and upper and lower portions of which are fixed to each other around the groove to form flange-shaped edges, wherein the edges are at least partially covered at ends with an insulating material.    
     
     
         2 . The lithium secondary battery of  claim 1 , wherein the insulating material is constructed in such a manner that it covers the whole ends of the edges in the pouch, excluding a portion from which electrode tabs are drawn out.  
     
     
         3 . The lithium secondary battery of  claim 1 , wherein the insulating material is formed by an adhesive tape.  
     
     
         4 . The lithium secondary battery of  claim 1 , wherein the pouch has an approximately rectangular shape when viewed from a direction of the thickness of the groove, the edges on both sides of the pouch are folded once in a forming direction of the groove, and the adhesive tape comprising the insulating material is attached over a part of its width to the edges and is attached over the rest of its width to surfaces forming the groove with the ends of the edges as its starting point.  
     
     
         5 . The lithium secondary battery of  claim 1 , wherein the pouch has an approximately rectangular shape when viewed from a direction of the thickness of the groove, the edges on both sides of the pouch are primarily folded into halves having half the width of the original and are secondarily folded toward the groove, and the insulating material is attached to the ends of the edges only in corner portions where a side for installing the protecting circuit module meets two lateral sides of the pouch.  
     
     
         6 . The lithium secondary battery of  claim 1 , wherein the pouch has an approximately rectangular shape when viewed from a direction of the thickness of the groove, and the insulating material is constructed in such a manner that it covers the whole ends of the edges on both the laterally parallel sides.