Secondary battery of improved safety

Abstract

Disclosed herein is a secondary battery having an electrode assembly received in a receiving part of a battery case, the electrode assembly being constructed in a structure in which pluralities of cathodes and anodes are stacked one on another while separators are disposed between the respective cathodes and anodes, and electrode taps extending from the stacked cathodes and anodes are coupled to electrode leads, wherein the receiving part of the battery case is provided at the outer upper end thereof with a depressed step such that at least a portion of the inner upper end of the receiving part of the battery case excluding the electrode taps-electrode lead coupling parts of the electrode assembly is in tight contact with the upper end of the electrode assembly.

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:

FIG. 1 is an exploded perspective view illustrating the general structure of a conventional pouch-shaped secondary battery;

FIG. 2 is an enlarged sectional view illustrating the inner upper end of a battery case of the secondary battery shown in FIG. 1, in which cathode taps are coupled to each other in a concentrated state and connected to a cathode lead;

FIG. 3 is a front see-through view illustrating the secondary battery of FIG. 1 in an assembled state;

FIG. 4 is an exploded perspective view illustrating a pouch-shaped secondary battery according to a preferred embodiment of the present invention;

FIG. 5 is a front see-through view illustrating the secondary battery of FIG. 4 in an assembled state;

FIG. 6 is a side see-through view illustrating the secondary battery of FIG. 4 in an assembled state;

FIG. 7 is a partial plan view illustrating a secondary battery according to another preferred embodiment of the present invention;

FIG. 8 is a front see-through view illustrating the secondary battery of FIG. 7.

Claims

1. A secondary battery having an electrode assembly received in a receiving part of a battery case, the electrode assembly being constructed in a structure in which pluralities of cathodes and anodes are stacked one on another while separators are disposed between the respective cathodes and anodes, and electrode taps extending from the stacked cathodes and anodes are coupled to electrode leads, wherein the receiving part of the battery case is provided at the outer upper end thereof with a depressed step such that at least a portion of the inner upper end of the receiving part of the battery case excluding the electrode taps-electrode lead coupling parts of the electrode assembly is in tight contact with the upper end of the electrode assembly.

2. The secondary battery according to claim 1, wherein the electrode assembly is constructed in a stacking structure and/or a stacking/folding structure.

3. The secondary battery according to claim 1, wherein the depressed step is formed at one side or each side of the upper end of the receiving part of the battery case.

4. The secondary battery according to claim 1, wherein the depressed step is formed at the middle of the upper end of the receiving part of the battery case corresponding to the space defined between the electrode taps-electrode lead coupling parts of the electrode assembly.

5. The secondary battery according to claim 3, wherein the depressed step extends from the upper end of the electrode assembly to the electrode taps-electrode lead coupling parts of the electrode assembly.

6. The secondary battery according to claim 1, wherein the depressed step is formed after the electrode assembly is mounted in the battery case or the battery case is sealed.

7. The secondary battery according to claim 1, wherein the depressed step is formed simultaneously when the receiving part is formed at the battery case.

8. The secondary battery according to claim 1, wherein the battery case is made of a laminate sheet including a metal layer and a resin layer, and the battery case is sealed by thermal welding after the electrode assembly is received in the receiving part of the battery case.

9. The secondary battery according to claim 8, wherein the thermal welding is also performed to the depressed step region when the battery case is sealed by the thermal welding.

10. The secondary battery according to claim 8, wherein the sheet is an aluminum laminate sheet.

11. The secondary battery according to claim 1, wherein the battery is a lithium-ion polymer battery.