Secondary battery and method for manufacturing the same
A secondary battery includes an electrode assembly including a first electrode bent in a zigzag shape, a second electrode bent in a zigzag shape to overlap the first electrode, and a separator bent in a zigzag shape to be interposed between the first and second electrodes; a can configured to accommodate the electrode assembly; and a cap part mounted in an opening of the can. An upper end of the first electrode is disposed on the uppermost end of the electrode assembly to extend longer than the second electrode, a lower end of the second electrode on the lowermost end of the electrode assembly extends longer than the first electrode, a first protrusion piece bonded to the cap part provided on the upper end of the first electrode, and a second protrusion piece bonded to the can provided on the lower end of the second electrode.
1 . A secondary battery comprising:
an electrode assembly comprising a first electrode bent in a zigzag shape, a second electrode bent in a zigzag shape to overlap the first electrode, and a separator bent in a zigzag shape to be interposed between the first and second electrodes;
a can configured to accommodate the electrode assembly; and
a cap mounted to an opening of the can,
wherein the first electrode comprises a first collector and a first electrode active material layer provided on a surface of the first collector facing the second electrode,
wherein the second electrode comprises a second collector and a second electrode active material layer provided on a surface of the second collector facing the first electrode,
wherein an upper end of the first electrode is disposed on an uppermost end of the electrode assembly to extend above the second electrode,
wherein a lower end of the second electrode is disposed on a lowermost end of the electrode assembly to extend under the first electrode,
wherein a first protrusion piece at a first end of the first electrode bonded to the cap is provided on the upper end of the first electrode, the first protrusion piece having a top surface, a bottom surface and an end surface,
wherein a second protrusion piece at a first end of the second electrode bonded to the can is provided on the lower end of the second electrode, the second protrusion piece having a top surface, a bottom surface and an end surface,
wherein the first protrusion piece is bonded to the cap while protruding toward the cap at an upper end of the first collector,
wherein the second protrusion piece is bonded to the can while protruding toward the can, at a lower end of the second collector,
wherein the upper end of the first electrode provided with the first protrusion piece may have a thickness greater than that of the remaining portion of the first electrode,
wherein the lower end of the second electrode provided with the second protrusion piece may have a thickness greater than that of the remaining portion of the second electrode,
wherein an insulating member having an insulating property covers the end surface of the first protrusion piece or the second protrusion piece.
2 . The secondary battery of claim 1 ,
wherein the first protrusion piece is provided as an embossing part.
3 . The secondary battery of claim 1 ,
wherein the first protrusion piece is provided as a wrinkle part, which is bent in a zigzag shape along a width direction of the can, at an upper end of the first collector.
4 . The secondary battery of claim 2 , wherein a conductive adhesive member for improving conductivity is provided on a portion of the first electrode at which the first collectors overlap each other.
5 . The secondary battery of claim 1 , wherein a protective member having an insulating property is provided on the cap facing the upper end of the first electrode.
6 . The secondary battery of claim 1 ,
wherein the second protrusion piece is provided as an embossing part.
7 . The secondary battery of claim 1 ,
wherein the second protrusion piece is provided as a wrinkle part, which is bent in a zigzag shape along a width direction of the can, at a lower end of the second collector.
8 . The secondary battery of claim 6 , wherein a conductive adhesive member for improving conductivity is provided on a portion of the second electrode, at which the second collectors overlap each other.
9 . The secondary battery of claim 1 , wherein a protective member having an insulating property is provided on the can facing the lower end of the second electrode.
10 . The secondary battery of claim 3 , wherein folds in the electrode assembly extend in a width direction, and
wherein the upper end of the first electrode has a width less than a width of a remaining portion of the first electrode.
11 . The secondary battery of claim 7 , wherein folds in the electrode assembly extend in a width direction, and
wherein the lower end of the second electrode has a width less than a width of a remaining portion of the second electrode.
12 . A method for manufacturing a secondary battery, the method comprising:
bending a first electrode in a zigzag shape, bending a second electrode in a zigzag shape to overlap the first electrode, and bending a separator, which is interposed between the first electrode and the second electrode, in a zigzag shape, wherein an upper end of the first electrode is above the second electrode, and a lower end of the second electrode is below the first electrode;
molding a first protrusion piece on the upper end of the first electrode and molding a second protrusion piece on the lower end of the second electrode;
overlapping the first electrode, the separator, and the second electrode, so as to assembly an electrode assembly, wherein the first protrusion piece formed on the upper end of the first electrode is disposed on an uppermost end of the electrode assembly, and the second protrusion piece formed on the lower end of the second electrode is disposed on a lowermost end of the electrode assembly;
accommodating the electrode assembly in a can, wherein the second protrusion piece disposed on the lowermost end of the electrode assembly is bonded to a bottom surface of the can; and
bonding a cap to an opening of the can, wherein the first protrusion piece disposed on the uppermost end of the electrode assembly is bonded to the cap,
wherein the first electrode comprises a first collector and a first electrode active material layer provided on a surface of the first collector facing the second electrode and an uncoated portion,
wherein the second electrode comprises a second collector and a second electrode active material layer provided on a surface of the second collector facing the first electrode and an uncoated portion, and
wherein the upper end of the first electrode provided with the first protrusion piece may have a thickness greater than that of the remaining portion of the first electrode,
wherein the lower end of the second electrode provided with the second protrusion piece may have a thickness greater than that of the remaining portion of the second electrode,
wherein an insulating member having an insulating property covers the end surface of the first protrusion piece or the second protrusion piece.
13 . The method of claim 12 , wherein the first protrusion piece is provided as an embossing part protruding toward the cap or a wrinkle part bent in a zigzag shape along a width direction of the can.
14 . The method of claim 13 , wherein the second protrusion piece is provided as an embossing part protruding toward the can or a wrinkle part bent in a zigzag shape along a width direction of the can.
15 . The secondary battery of claim 1 , wherein a top surface of the first protrusion piece extends above the upper end of the electrode assembly and a top surface of the second protrusion piece extends below the lowermost end of the electrode assembly.