Secondary battery having tab with blowing agent and manufacturing method thereof

1. A secondary battery, comprising:

an electrode assembly including a first electrode plate having a first tab made from the same material as the first electrode plate;

a first active material coated on a surface of the first electrode plate but not the first tab;

a second electrode plate having a second tab made from the same material as the second electrode plate;

a second active material coated on a surface of the second electrode plate but not on the second tab;

a separator;

a case having a receiving portion for receiving the electrode assembly and an electrolyte therein;

a first lead having a first end connected to the first tab and a second end extending through the case;

a second lead having a first end connected to the second tab and a second end extending through the case; and

a blowing agent applied on at least one of the first tab and the second tab which are located within the receiving portion, the blowing agent expanding at a predetermined temperature.

2. The secondary battery of claim 1 , further comprising:

a notch on at least one side of the first and second tabs and extending inwardly a predetermined distance on a same line with the blowing agent.

3. The secondary battery of claim 1 , further comprising:

a weld portion welded symmetrically with regard to the blowing agent, to suppress the first and second tabs from moving when the blowing agent expands.

4. The secondary battery of claim 2 ,

wherein the notch extends inwardly at opposite sides of the first and second tabs.

5. The secondary battery of claim 2 , wherein the notch has a shape of V or U.

6. The secondary battery of claim 1 , further comprising:

a plurality of first tabs; and

a plurality of second tabs,

wherein the first tabs are stacked and the second tabs are stacked, and

wherein the blowing agent is interposed between the stacked tabs.

7. The secondary battery of claim 1 , wherein the blowing agent is a polymer capsule-type physical blowing agent.

8. The secondary battery of claim 3 , wherein the weld portion is formed along the entire width of the tab.

9. A method for manufacturing a secondary battery, comprising:

applying a first blowing agent onto each first tab of a plurality of first electrode plates;

applying a second blowing agent onto each second tab of a plurality of second electrode plates;

forming a first notch on at least one side of each first tab;

forming a second notch on at least one side of each second tab;

arranging the first electrode plates, a separator and the second electrode plates in order, and integrating the first and second tabs such that the first and second notches are aligned with each other, respectively;

forming an electrode assembly by connecting ends of the first tabs to a first lead and ends of the second tabs to a second lead;

receiving the electrode assembly and an electrolyte in a case, such that a portion of the first and second blowing agents are received within the case and the first and second leads protrude through the case; and

sealing the case tightly,

wherein the first and second blowing agents expand at a predetermined temperature.

10. The method of claim 9 , further comprising:

forming first and second welding portions on the first and second tabs at a predetermined distance spaced away from the first and second blowing agents, respectively, after integrating the tabs.

11. The secondary battery of claim 2 , further comprising:

a plurality of first tabs; and

a plurality of second tabs,

wherein the first tabs are stacked and the second tabs are stacked, and

wherein the blowing agent is interposed between the stacked tabs.

12. The secondary battery of claim 2 , wherein the blowing agent is a polymer capsule-type physical blowing agent.

13. The secondary battery of claim 2 , wherein the notch extends inwardly at opposite sides of the first and second tabs.

14. The secondary battery of claim 1 , wherein the predetermined temperature is in a range between 80° to 100° C.

15. The secondary battery of claim 1 , wherein the predetermined temperature is in a range between 130° to 150° C.

16. The method of claim 9 , wherein the predetermined temperature is in a range between 80° to 100° C.

17. The method of claim 9 , wherein the predetermined temperature is in a range between 130° to 150° C.

18. The secondary battery of claim 1 , wherein the first tab and the second tab are within the case.

19. The method of claim 9 , further comprising arranging the first tab and the second tab within the case,

wherein the blowing agent is applied to the first tab and the second tab.