Secondary battery

1. A secondary battery comprising;

an electrode assembly comprising a first electrode plate, a second electrode plate, and a separator between the first electrode plate and the second electrode plate;

a case containing the electrode assembly and an electrolyte;

an electrode terminal electrically connected to the first electrode plate;

a current collector coupled between and electrically connecting the first electrode plate and the electrode terminal, the current collector comprising a current collecting plate coupled to an uncoated part of the first electrode, plate, and a lead member coupled between the electrode terminal and the current collecting plate and contacting the electrolyte;

a fuse formed as a portion of the lead member spaced apart from the first electrode plate and having a smaller cross-sectional area and a higher resistance than other portions of the lead member including portions of the lead member that are adjacent to opposite sides of the fuse and integrally formed with the fuse of a single material; and

an insulating unit covering the fuse of the current collector, the insulating unit exposed to the electrolyte and blocking the fuse from the electrolyte,

wherein the insulating unit surrounds a perimeter of the fuse and a perimeter of the portions of the lead member that are adjacent to the opposite sides of the fuse,

wherein the lead member comprises:

a terminal lead unit coupled to the electrode terminal; and

a current collecting lead unit extending from the terminal lead unit and coupled to the current collecting plate, and

wherein the current collecting lead unit or the terminal lead unit comprises the fuse.

2. The secondary battery of claim 1 , wherein the insulating unit has a larger surface than the fuse.

3. The secondary battery of claim 1 , wherein the fuse has a higher resistance than portions of the current collector.

4. The secondary battery of claim 1 , wherein the electrode terminal protrudes outside the case.

5. The secondary battery of claim 4 , further comprising a cap plate sealing an opening of the case, wherein the electrode terminal protrudes through a terminal hole formed in the cap plate.

6. The secondary battery of claim 1 , wherein the insulating unit comprises at least one of an insulating tape or an insulation molding.

7. The secondary battery of claim 1 , wherein the current collector is formed as a single integral piece.

8. The secondary battery of claim 1 ,

wherein the electrode terminal is a first electrode terminal, and the secondary battery further comprises a second electrode terminal electrically connected to the second electrode plate and protruding outside the case, and

wherein the current collector is a first current collector, and the secondary battery further comprises a second current collector coupled between and electrically connecting the second electrode plate and the second electrode terminal.

9. The secondary battery of claim 8 ,

wherein the first electrode plate is a positive electrode plate and the first current collector is a positive current collector, and

wherein the second electrode plate is a negative electrode plate and the second current collector is a negative current collector.

10. The secondary battery of claim 8 , wherein the first current collector comprises aluminum, and the second current collector comprises copper.

11. The secondary battery of claim 1 , wherein the fuse is configured to melt and disconnect the first electrode plate from the electrode terminal when a current having a magnitude greater than or equal to a set current flows through the current collector.

12. The secondary battery of claim 1 , wherein the insulating unit completely covers the fuse.

13. The secondary battery of claim 1 , wherein the current collector including the fuse is formed of a single material.

14. The secondary battery of claim 13 , wherein the current collector including the fuse is formed of aluminum.

15. The secondary battery of claim 1 , wherein the insulating unit wraps the fuse.