Unit cell for secondary battery with improved wettability and method for manufacturing the same
A unit cell for a secondary battery includes a central electrode having a first polarity, a pair of separators respectively laminated on both surfaces the central electrode, and an upper electrode and a lower electrode respectively laminated on the pair of separators and having a second polarity, wherein the separator has a patterned adhesive force.
1. A unit cell for a secondary battery, the unit cell comprising:
a central electrode having a first polarity;
a pair of separators respectively laminated on opposite surfaces of the central electrode, and including a first separator and a second separator; and
an upper electrode and a lower electrode respectively laminated on the first separator and the second separator, and located as outermost layers of the unit cell, the upper electrode and the lower electrode having a second polarity,
wherein, at an interface between the upper electrode and the first separator and at an interface between the lower electrode and the second separator, each of the first separator and the second separator has a patterned adhesive force having a first region with a first adhesive force and a second region with a second adhesive force that is weaker than the first adhesive force.
2. The unit cell for a secondary battery according to claim 1 , wherein the first region is a region treated with plasma, and the second region is a region not treated with plasma.
3. A method for manufacturing a unit cell for a secondary battery, the method comprising:
supplying a central electrode;
supplying first and second separators respectively onto opposite surfaces of the central electrode;
treating surfaces of each of the first and second separators with plasma, so that a first region of the surfaces is treated with plasma and a second region of the surfaces is not treated with plasma;
supplying an upper electrode and a lower electrode respectively onto the first separator and the second separator; and
laminating the central electrode, the upper electrode, the lower electrode and the first and second separators so that the central electrode, the upper electrode and the lower electrode are respectively adhered to the first separator and the second separator, and the upper electrode and the lower electrode are located as outermost layers of the unit cell,
wherein, at an interface between the upper electrode and the first separator and at an interface between the lower electrode and the second separator, each of the first separator and the second separator has a patterned adhesive force having the first region with the first adhesive force and the second region with the second adhesive force that is weaker than the first adhesive force.
4. The method for manufacturing a unit cell for a secondary battery according to claim 3 , wherein the laminating step includes,
applying heat onto the upper electrode and the lower electrode; and
applying pressure onto the heated upper and lower electrodes to be compressed.
5. The method for manufacturing a unit cell for a secondary battery according to claim 3 , further comprising:
cutting the central electrode, the upper electrode, the lower electrode the first separator and the second separator into predetermined lengths.
6. The method for manufacturing a unit cell for a secondary battery according to claim 3 , further comprising:
inspecting and discharging the completely laminated unit cell for a secondary battery.
7. The unit cell for a secondary battery according to claim 1 , further comprising electrolyte,
wherein the electrolyte is impregnated higher in the second region than the first region.
8. The unit cell for a secondary battery according to claim 7 , wherein the electrolyte is impregnated to about 18 mm to 26 mm from a bottom of the second region.
9. The method for manufacturing a unit cell for a secondary battery according to claim 3 , further comprising electrolyte,
wherein the electrolyte is impregnated higher in the second region than the first region.
10. The method for manufacturing a unit cell for a secondary battery according to claim 9 , wherein the electrolyte is impregnated to about 18 mm to 26 mm from a bottom of the second region.
11. The unit cell for a secondary battery according to claim 1 , wherein the number of separators is the same as the total number of upper and lower electrodes.
12. The method for manufacturing a unit cell for a secondary battery according to claim 3 , wherein the number of separators is the same as the total number of upper and lower electrodes.