BATTERY ASSEMBLY EMPLOYED WITH SEPARATOR OF SEALED TOP PORTION AND SECONDARY BATTERY COMPRISING THE SAME

Abstract

Disclosed herein are an electrode assembly having separators the upper ends of which are sealed and a secondary battery including the same. The electrode assembly has a cathode/separator/anode structure that can be charged and discharged. The separators, which protrude beyond the upper ends of the electrodes, are bent in one direction, the separators are heat-treated such that the bent state of the separators is fixed, and an insulative coating layer is formed at the bent surfaces of the separators. Consequently, foreign matter is prevented from being introduced into the electrode assembly, and therefore, the safety of electrode assembly is improved.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIGS. 1 to 4 are typical views illustrating a process for manufacturing an electrode assembly according to a preferred embodiment of the present invention.

Claims

1. An electrode assembly having a cathode/separator/anode structure that can be charged and discharged, wherein the separators, which protrude beyond the upper ends of the electrodes, are bent in one direction, the separators are heat-treated such that the bent state of the separators is fixed, and an insulative coating layer is formed at the bent surfaces of the separators.

2. The electrode assembly according to claim 1, wherein the separators protrude by a length of 1.5 mm to 3 mm from the upper ends of the electrodes.

3. The electrode assembly according to claim 2, wherein the upper ends of the anodes protrude higher than those of the cathodes, and the separators protrude from the upper ends of the anodes.

4. The electrode assembly according to claim 1, wherein the heat-treatment fixing operation is performed at a temperature above a glass transition temperature of a separator material or a temperature below a melting point of the separator material.

5. The electrode assembly according to claim 1, wherein the insulative coating layer is formed by applying a molten insulation material to the bent upper ends of the separators and solidifying the molten insulation material.

6. The electrode assembly according to claim 5, wherein the molten insulation material is a polyolefin resin being the same polymer resin as a material for the separators.

7. The electrode assembly according to claim 1, wherein the coating layer has a thickness of 1 mm to 3 mm.

8. The electrode assembly according to claim 1, wherein the electrode assembly is a jelly-roll type electrode assembly or a stacking type electrode assembly.

9. An electrode assembly having a cathode/separator/anode structure that can be charged and discharged, wherein the separators, which protrude beyond the upper ends of the electrodes, are bent in one direction, the separators are heat-treated at a temperature in a range between the glass transition temperature of a separator material and the melting point of the separator material such that the bent state of the separators is fixed.

10. A secondary battery including an electrode assembly according to claim 1.

11. The secondary battery according to claim 10, wherein the secondary battery has no additional insulating member mounted to the upper end of the electrode assembly.