Rechargeable battery having current collector plate with protrusion

1. A rechargeable battery, comprising:

an electrode assembly including first and second electrode plates, each of which includes an electrode uncoated portion, and a separator interposed between the first and second electrode plates, the electrode assembly having a direction; and

at least one current collector plate, each current collector plate contacting one of the electrode uncoated portions of the first and second electrode plates,

wherein each current collector plate includes:

a base portion and a side portion, the side portion extending toward each electrode uncoated portion of the electrode assembly from peripheral edges of the base portion,

a protrusion protruding toward the electrode assembly from the base portion and having a contact portion contacting one of the electrode uncoated portions, the contact portion of the protrusion being a first surface of the protrusion, and the first surface of the protrusion facing the separator in the electrode assembly,

a slit in the contact portion extending through the side portion and disposed at a predetermined angle with respect to the direction of the electrode assembly, and

a laser welding line in the first surface of the protrusion surrounding the slit.

2. The rechargeable battery as claimed in claim 1 , wherein the slit is disposed in a direction perpendicular to the direction of the electrode assembly, and the electrode uncoated portions are bent away from the slit.

3. The rechargeable battery as claimed in claim 1 , wherein the contact portion has a center and the slit is disposed at the center of the contact portion.

4. The rechargeable battery as claimed in claim 3 , wherein the protrusion has a lengthwise direction and the slit is disposed parallel to the lengthwise direction of the protrusion.

5. The rechargeable battery as claimed in claim 1 , wherein the slit is disposed at a peripheral region of the contact portion.

6. The rechargeable battery as claimed in claim 1 , wherein the contact portion includes a plurality of slits.

7. The rechargeable battery as claimed in claim 1 , wherein the slit is disposed in a straight line configuration.

8. The rechargeable battery as claimed in claim 6 , wherein the plurality of slits is disposed in a dotted line configuration.

9. The rechargeable battery as claimed in claim 1 , wherein the slit includes:

a first slit disposed at a predetermined angle with respect to the direction of the electrode assembly; and

a plurality of second slits extending from the first slit in a direction perpendicular to the first slit.

10. The rechargeable battery as claimed in claim 1 , wherein the slit has an inside edge and the laser welding line is disposed on the inside edge of the slit.

11. The rechargeable battery as claimed in claim 10 , wherein the slit has a width of about 0.1 to about 0.3 mm.

12. The rechargeable battery as claimed in claim 1 , further comprising:

a case receiving the electrode assembly and the current collector plate; and

a cap assembly sealing the case,

wherein the battery is a cylindrical rechargeable battery having a wound electrode assembly.

13. The rechargeable battery as claimed in claim 12 , wherein the current collector plate further includes:

the base portion having edges, a center and a circular plate shape facing the electrode uncoated portion of the electrode assembly;

a welding portion protruding toward the cap assembly from the center of the base portion; and

an electrolyte solution injection hole disposed between the center and the edges of the base portion,

wherein the protrusion is disposed between the center and the edges of the base portion and adjacent to the electrolyte solution injection hole.

14. The rechargeable battery as claimed in claim 1 , wherein the slit defines an empty space, the empty space exposing electrode uncoated portions bent perpendicularly with respect to electrode coated portions.