Rechargeable battery

1. A rechargeable battery, comprising:

an electrode assembly including a first electrode, a second electrode, and a separator interposed therebetween;

a center pin at a center of the electrode assembly, the center pin including a bonding portion electrically coupled to the first electrode, and a terminal portion connected to one end of the bonding portion;

a case housing the electrode assembly; and

a gasket insulating between the center pin and the case, the gasket enclosing an edge of the terminal portion of the center pin, and the gasket including:

a first insulating portion between a lateral surface of the terminal portion and the case, and

a second insulating portion overlapping a topmost surface of the terminal portion and having an opening for exposing the topmost surface of the terminal portion,

wherein a sidewall of the case extends to a higher level than the center pin, a topmost surface of the sidewall being above the topmost surface of the terminal portion of the center pin, and

wherein the topmost surface of the sidewall of the case is level with a topmost surface of the second insulating portion of the gasket.

2. The rechargeable battery as claimed in claim 1 , wherein the gasket is between the terminal portion and the case to close and seal an opening of the case.

3. The rechargeable battery as claimed in claim 1 , wherein a topmost surface of the second insulating portion is at a higher level than the topmost surface of the terminal portion relative to the bonding portion of the center pin.

4. The rechargeable battery as claimed in claim 1 , wherein the gasket further includes a third insulating portion overlapping a bottom surface of the terminal portion, the third insulating portion including an opening through which the bonding portion penetrates.

5. The rechargeable battery as claimed in claim 1 , wherein the gasket further includes a fourth insulating portion along one end of the second insulating portion, the fourth insulating portion being on the top surface of the terminal portion and protruding in a direction perpendicular to the top surface of the terminal portion.

6. The rechargeable battery as claimed in claim 1 , wherein the case includes:

a first plate in parallel to the bonding portion;

a second plate connected to a first end of the first plate and defining a space for housing the electrode assembly; and

a third plate connected to a second end of the first plate and having an opening for exposing the terminal portion.

7. The rechargeable battery as claimed in claim 6 , wherein the third plate contacts and overlaps the second insulating portion.

8. The rechargeable battery as claimed in claim 7 , wherein a width of the opening of the second insulating portion is smaller than or equal to a width of the opening of the third plate.

9. The rechargeable battery as claimed in claim 6 , wherein the case further comprises a fixing member on one surface of the second plate, the bonding portion of the center pin being inserted into the fixing member.

10. The rechargeable battery as claimed in claim 1 , wherein the case includes a conductive material.

11. The rechargeable battery as claimed in claim 10 , wherein the second electrode is electrically coupled to the case.

12. The rechargeable battery as claimed in claim 11 , wherein each of the first and second electrodes includes an electrode region with an active material and an electrode uncoated region without an active material, the electrode uncoated region of the first electrode being electrically coupled to the bonding portion, and the electrode uncoated region of the second electrode being electrically coupled to the case.

13. The rechargeable battery as claimed in claim 1 , wherein the case further comprises a beading portion depressed toward the gasket.

14. The rechargeable battery as claimed in claim 1 , wherein the gasket is at least on two different surfaces of the terminal portion of the center pin.

15. The rechargeable battery as claimed in claim 1 , wherein the gasket continuously extends along a lateral surface of the terminal portion and a portion of an upper surface of the terminal portion.

16. The rechargeable battery as claimed in claim 1 , wherein an upper portion of the case overlaps lateral surfaces of the terminal portion, the gasket completely separating between the terminal portion and the case.

17. The rechargeable battery as claimed in claim 1 , wherein the first insulating portion covers the entire lateral surface of the terminal portion.