Rechargeable battery

1. A rechargeable battery, comprising:

an electrode assembly including a positive electrode, a negative electrode, and a separator therebetween;

a case housing the electrode assembly;

a cap plate sealing an opening of the case; and

an electrode terminal installed in the cap plate,

wherein the electrode terminal includes:

a first terminal section in a terminal hole of the cap plate, the first terminal section being connected to the electrode assembly in the case and including a protruding portion that protrudes outwardly from the cap plate, the protruding portion having a receiving portion therein,

a second terminal section in the receiving portion, the second terminal section protruding outwardly from the receiving portion, and

a fastening member between an inner peripheral surface of the receiving portion and the second terminal section, the fastening member fastening the first terminal section and the second terminal section to each other.

2. The rechargeable battery as claimed in claim 1 , wherein:

the receiving portion is formed by a cylindrical space,

the receiving portion includes a concave rotation-preventing groove protruding outwardly in a radial direction, and

the second terminal section includes a rotation-preventing projection, the rotation-preventing projection being convex outwardly in the radial direction and being coupled to the rotation-preventing groove.

3. The rechargeable battery as claimed in claim 2 , wherein:

the receiving portion includes a plurality of the rotation-prevention grooves,

the second terminal section includes a plurality of the rotation-preventing projections, and

the plurality of rotation-preventing grooves and rotation-preventing projections are arranged at regular intervals along a circumferential direction of the receiving portion and are correspondingly coupled to each other.

4. The rechargeable battery as claimed in claim 2 , wherein the fastening member includes:

a ring portion that closely contacts the rotation-preventing projection, and

a fastening protrusion that protrudes from the ring portion, the fastening protrusion being coupled to a fastening groove on the inner peripheral surface of the receiving portion, which inner peripheral surface faces the ring portion.

5. The rechargeable battery as claimed in claim 4 , wherein:

the fastening groove includes a horizontal bottom surface that extends outwardly in the radial direction from the inner peripheral surface of the receiving portion, and

the fastening protrusion includes:

a horizontal top surface that closely contacts the horizontal bottom surface of the fastening groove, and

an inclined surface that is inclined toward a lower part of the ring portion from an end of the horizontal top surface.

6. The rechargeable battery as claimed in claim 4 , wherein:

the fastening groove extends continuously along a circumference of the inner peripheral surface of the receiving portion, and

the fastening protrusion extends continuously along a circumference of an outer peripheral surface of the ring portion.

7. The rechargeable battery as claimed in claim 4 , wherein:

the first terminal section and the second terminal section are made of a conductive material, and

the fastening member is made of a resin injection material.

8. The rechargeable battery as claimed in claim 2 , wherein the fastening member includes:

a ring portion that closely contacts the rotation-preventing projection,

a fastening protrusion that protrudes from the ring portion, the fastening protrusion being coupled to a fastening groove on the inner peripheral surface of the receiving portion, which inner peripheral portion faces the ring portion, and

an auxiliary rotation-preventing projection that protrudes from the ring portion, the auxiliary rotation-preventing projection being coupled to the rotation-preventing groove.

9. The rechargeable battery as claimed in claim 8 , wherein:

the receiving portion includes a plurality of the rotation-prevention grooves and a plurality of the fastening grooves, and

the fastening grooves and the rotation-preventing grooves are alternately disposed in along a circumferential direction of the receiving portion.

10. The rechargeable battery as claimed in claim 9 , wherein:

the receiving portion further includes a separation-preventing groove that extends from the rotation-preventing groove along the circumferential direction, and

the ring portion includes a projection receiving groove that contacts the rotation-preventing projection to correspond to the separation-preventing groove so that the rotation-preventing projection is inserted into the separation-preventing groove.

11. The rechargeable battery as claimed in claim 9 , wherein the ring portion includes a plurality of fastening protrusions, the plurality of fastening protrusions being on an outer circumferential surface of the ring portion and corresponding to the fastening grooves.

12. The rechargeable battery as claimed in claim 11 , wherein:

the fastening groove includes a horizontal bottom surface extending outwardly in the radial direction from the inner peripheral surface of the receiving portion,

the fastening protrusion includes:

a horizontal top surface that closely contacts the horizontal bottom surface, and

an inclined surface that is inclined toward a lower part of the ring portion from an end of the horizontal top surface, and

the fastening groove and the fastening protrusion have about the same length in the circumferential direction.

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

an outer insulator between an outer part of the first terminal section and the cap plate; and

an inner insulator between a lead tab of the electrode assembly connected to an inner part of the first terminal section and the cap plate.