Method for manufacturing electrode assembly for secondary battery
Disclosed is a method for manufacturing a secondary battery. More specifically, the present disclosure relates to a method for manufacturing an electrode assembly by stacking a plurality of bi-cell type and/or monocell type unit cells. A method for manufacturing an electrode assembly according to the present disclosure can easily remove the curvature which occurs in a unit cell in a roll lamination process, and fabricate a flat plate electrode assembly with a simple process. Further, when the electrode assembly is manufactured with the method described above, the curvature between the unit cells constituting the electrode assembly may be offset, and accordingly, a time during which the flat plate shape in the electrode assembly is maintained may be extended significantly.
1. A method for manufacturing a flat plate electrode assembly, comprising:
piling first and second unit cell stacks curved in a C shape and having a certain curvature radius so that concave surfaces thereof face each other; and
removing a curvature from the unit cell stack by pressing the piled first and second unit cell stacks.
2. The method of claim 1 , wherein, at the step of piling, a curvature radius of the concave surface of the first unit cell stack is −10% to +10% of a curvature radius of the concave surface of the second unit cell stack.
3. The method of claim 1 , wherein, at the step of piling, a curvature central axis of each of the unit cell stacks is positioned on a vertical plane to a facing plane of the unit cell stacks.
4. The method of claim 1 , wherein the first and second unit cell stacks are respectively monocell and/or bi-cell.
5. The method of claim 1 , wherein the flat plate electrode assembly is bi-cell type and/or monocell type.
6. The method of claim 1 , wherein the first and second unit cell stacks are respectively one unit monocell or one unit bi-cell, or are respectively formed by stacking two or more unit monocells or unit bi-cells.
7. The method of claim 1 , wherein the flat plate electrode assembly is monocell type or bi-cell type in which a plurality of electrodes and a plurality of separators are alternated and stacked, and the separator is interposed between the two opposite electrodes.
8. The method of claim 7 , wherein the flat plate electrode assembly is bi-cell type in which a polarity of the electrode disposed on an uppermost end portion and a polarity of the electrode disposed on a lowermost end portion are same as each other.
9. The method of claim 7 , wherein the flat plate electrode assembly is monocell type in which the electrode disposed on an uppermost end portion and the electrode disposed on a lowermost end portion are opposite each other.
10. The method of claim 1 , wherein, at the step of piling, a third unit cell stack having a flat planar shape is inserted between the first unit cell stack and the second unit cell stack.
11. The method of claim 10 , wherein the third unit cell stack is monocell type or bi-cell type.
12. The method of claim 1 , wherein the pressing is performed toward a center surface of the electrode assembly, in a vertical direction to a facing plane of the first and second unit cell stacks.
13. The method of claim 1 , wherein the pressing is performed by using a pair of jigs including an upper pressing member and a lower support member, and the upper pressing member and the lower support member have flat plate shapes.
14. The method of claim 1 , wherein the first unit cell stack and the second unit cell stack have the same curvature radius, the same horizontal length, and the same vertical length.
15. The method of claim 1 , wherein the curvature of each of the unit cell stacks is naturally formed due to a roll lamination process.
16. The method of claim 1 , after the step of removing, the electrode assembly formed by removing the curvature is taped for fixation.
17. A lithium ion secondary battery, comprising the electrode assembly of claim 1 .