Secondary battery with electrode tab made of copper-nickel alloy

1. A secondary battery configured to have a structure in which an electrode assembly of a cathode/separator/anode structure is mounted in a battery case in a state in which the electrode assembly is impregnated with an electrolyte, wherein electrode tabs are attached to active material uncoated portions of electrode plates of the electrode assembly, and an anode tab, which is one of the electrode tabs and one end of which is attached to the battery case, is made of a Cu—Ni alloy,

wherein the anode tab is configured to have a two-layer structure in which one layer attached to a corresponding one of the electrode plates is a Cu—Ni alloy layer and the other layer stacked on the Cu—Ni alloy layer is a copper layer, and

wherein a Ni content of the Cu—Ni alloy is 0.05% to 3% based upon the total weight of the alloy.

2. The secondary battery according to claim 1 , wherein the battery case is a cylindrical can.

3. The secondary battery according to claim 1 , wherein the anode tab is attached to a lower end of an inside of the battery case.

4. The secondary battery according to claim 1 , wherein the Cu—Ni alloy further contains at least one element selected from Si and Sn.

5. The secondary battery according to claim 1 , wherein a content of Si is 0.05% to 0.80% based upon the total weight of the alloy, and a content of Sn is 0.10% to 0.70% based upon the total weight of the alloy.

6. The secondary battery according to claim 1 , wherein the anode tab is formed of a strip-shaped member having a width of 2 mm to 8 mm, a length of 10 mm to 90 mm, and a thickness of 0.05 mm to 0.5 mm.

7. The secondary battery according to claim 1 , wherein the electrode assembly is a jelly roll configured to have a structure in which a cathode sheet and an anode sheet are wound in a state in which a separator is disposed between the cathode sheet and the anode sheet.

8. The secondary battery according to claim 1 , wherein the anode tab is attached to the corresponding one of the electrode plates by ultrasonic welding, and one end of the anode tab is attached to an inside of the battery case by resistance welding.

9. The secondary battery according to claim 1 , wherein the secondary battery is a lithium secondary battery.

10. A battery pack comprising the lithium secondary battery according to claim 9 as a unit cell.

11. A device comprising the battery pack according to claim 10 as a power source.

12. The device according to claim 11 , wherein the device is selected from a group consisting of a mobile electronic device, an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, and a power storage device.

13. A secondary battery configured to have a structure in which an electrode assembly of a cathode/separator/anode structure is mounted in a battery case in a state in which the electrode assembly is impregnated with an electrolyte, wherein electrode tabs are attached to active material uncoated portions of electrode plates of the electrode assembly, and an anode tab, which is one of the electrode tabs and one end of which is attached to the battery case, is made of a Cu—Ni alloy,

wherein the anode tab is configured to have a three-layer structure in which an upper Cu—Ni alloy layer and a lower Cu—Ni alloy layer are stacked in a state in which a copper layer is disposed between the upper Cu—Ni alloy layer and the lower Cu-Ni alloy layer, and

wherein a Ni content of the Cu—Ni alloy is 0.05% to 3% based upon the total weight of the alloy.

14. The secondary battery according to claim 13 , wherein the Cu—Ni alloy further contains at least one element selected from Si and Sn.

15. The secondary battery according to claim 14 , wherein a content of Si is 0.05% to 0.80% based upon the total weight of the alloy and a content of Sn is 0.10% to 0.70% based upon the total weight of the alloy.