Method for manufacturing secondary battery and method for manufacturing electrode assembly

1. A method for manufacturing a secondary battery, the method comprising:

a first process (S 10 ) of manufacturing an incomplete electrode assembly in which a plurality of electrodes and a plurality of separators are alternately stacked;

a second process (S 20 ) of partially pressing the incomplete electrode assembly to pattern-bond an interface between the electrode and the separator and thereby to manufacture a complete electrode assembly in which a bonding portion and a nonbonding portion coexist on the interface between the electrode and the separator;

a third process (S 30 ) of accommodating the complete electrode assembly into a case;

a fourth process (S 40 ) of injecting an electrolyte through an opening of the case to impregnate the electrolyte into the electrode assembly, wherein the electrolyte is permeated into nonbonding portion of the interface between the electrode and the separator and impregnated up to the inside of the electrode assembly;

a fifth process (S 50 ) of sealing an unsealed surface in which the opening of the case is formed to manufacture a secondary battery; and

a sixth process (S 60 ) of heating and pressing an entire surface of the secondary battery to bond the nonbonding portion of the interface between the electrode and the separator.

2. The method of claim 1 , wherein, in the incomplete electrode assembly, the plurality of electrodes are provided with a first electrode and a second electrode, and the plurality of separators are provided with a first separator and a second separator.

3. The method of claim 2 , wherein the incomplete electrode assembly comprises a radical unit in which a first electrode, a first separator, a second electrode, and a second separator are sequentially stacked or has a structure in which at least two or more radical units are stacked.

4. The method of claim 2 , wherein the incomplete electrode assembly is provided with a first radical unit and a second radical unit, which are vertically stacked with a separation sheet therebetween,

the first radical unit has a structure in which the first electrode, the first separator, the second electrode, the second separator, and the first electrode are sequentially stacked, and

the second radical unit has a structure in which the second electrode, the second separator, the first electrode, the first separator, and the second electrode are sequentially stacked.

5. The method of claim 2 , wherein the first electrode is a negative electrode, and the second electrode is a positive electrode.

6. The method of claim 2 , wherein, in the second process (S 20 ), the incomplete electrode assembly is partially heated and pressed through a pattern roller to manufacture the complete electrode assembly in which the interface between the electrode and the separator is pattern-bonded.

7. The method of claim 6 , wherein the pattern roller comprises a roller part disposed on a top or bottom surface of the incomplete electrode assembly and having rotational force and a patterned pressing protrusion disposed on an outer circumferential surface of the roller part to partially heat and press the top or bottom surface of the incomplete electrode assembly.

8. The method of claim 7 , wherein the roller part is disposed in a width direction of the incomplete electrode assembly,

the pressing protrusion is formed in a circumferential direction of the roller part to form a bonding portion that is patterned in a linear shape on the interface between the electrode and the separator, which is pressed by the pressing protrusion, and

a nonbonding portion has a linear shape is formed on the interface between the electrode and the separator, which is not pressed by the pressing protrusion.

9. The method of claim 1 , wherein the sixth process is performed by a heating and pressing device that heats and presses both surfaces of the secondary battery at the same time.

10. The method of claim 9 , wherein the heating and pressing device comprises a pressing body on which the secondary battery is mounted and a pressing part comprising a heat generation plate that heats and presses the secondary battery mounted on the pressing body.

11. The method of claim 10 , wherein the heat generation plate is provided as a metal plate comprising a built-in heating wire.

12. The method of claim 1 , wherein, in the fifth process (S 50 ), an unsealed surface in which an opening of the case is formed is press-fitted, and simultaneously, heat is applied to the unsealed surface to seal an entire sealing surface.

13. The method of claim 1 , after the sixth process (S 60 ), further comprising a seventh process (S 70 ) of charging and discharging the secondary battery to manufacture the complete secondary battery.