Degassing method of secondary battery using centrifugal force

1. A method for manufacturing a battery cell including an electrode assembly and electrolyte provided in a battery case made of a laminate sheet having a resin layer and a metal layer, comprising:

(a) mounting the electrode assembly in the battery case and sealing the periphery of the battery case except for one end part of the battery case through thermal fusion;

(b) introducing the electrolyte through the end part of the battery case and sealing the end part of the battery case via thermal fusion;

(c) charging-discharging the battery cell to activate the battery cell;

(d) transferring gas generated during activation and excess electrolyte to the end part of the battery case by centrifugal force; and

(e) removing the gas and excess electrolyte from the end part of the battery case,

wherein, in step (d), the battery cell is mounted on a centrifugal separator to make the end part of the battery case face an inside of the centrifugal separator and then rotated, enabling the gas to migrate to the end part of the battery case by centrifugal force.

2. The method according to claim 1 , wherein the laminate sheet has a laminate structure comprising an external resin layer, a barrier metal layer for shielding air and moisture, and a thermally fusible internal resin layer.

3. The method according to claim 1 , wherein the electrode assembly has a winding type, stack type or stack/folding type structure.

4. The method according to claim 1 , wherein the battery case has a rectangular structure in a plan view and the end part of the battery case is one edge side of the battery case.

5. The method according to claim 4 , wherein a width of the edge side is 20 to 300% larger than each width of the other edge sides and the end of the edge side is sealed during thermal fusion for activation.

6. The method according to claim 1 , wherein, in operation (d), an entirety of the gas migrates to the end part of the battery case by centrifugal force.

7. The method according to claim 1 , wherein operation (e) includes: (e1) puncturing an unsealed part in the end part of the battery case to form a through-hole communicating with the battery case; and (e2) pulling top and bottom faces of the battery case in an opposite direction to each other at the unsealed part to open the top and bottom faces of the battery case while applying vacuum pressure thereto, to remove excess electrolyte as well as the gas generated during activation.

8. The method according to claim 7 , wherein the top and bottom faces of the battery case are pulled in opposite directions by a suction device while applying vacuum pressure thereto.

9. The method according to claim 8 , wherein the suction device comprises a first suction pad contacting the top face of the battery case and a second suction pad contacting the bottom face of the battery case.

10. The method according to claim 9 , wherein each of the first suction pad and the second suction pad has a structure comprising an adhesion part contacting an outer side of the battery case and a hollow part that is connected to the adhesion part, communicates with a through-hole formed at an unsealed part of the battery case and applies vacuum pressure.

11. The method according to claim 1 , wherein heating the battery cell is conducted in at least one of operations (c) to (e).

12. The method according to claim 1 , wherein ultrasonic vibration is applied to the battery cell in at least one of operations (c) to (e).

13. The method according to claim 1 , further comprising an operation of sealing an inner side of the unsealed part through thermal fusion and then cutting off other outer parts, after operation (e).