Pouch type secondary battery and method of manufacturing the same

1. A method of manufacturing a pouch type secondary battery, comprising:

preparing a pouch type case provided with a receiving part for receiving an electrode assembly and a gas collecting part connected to the receiving part for collecting gas generated in the receiving part;

receiving the electrode assembly in the pouch type case;

sealing an outer part of the pouch type case by heat welding;

injecting an electrolyte in the pouch type case;

activating the pouch type secondary battery and collecting gas generated during activating through the gas collecting part;

heat welding a boundary of the receiving part and the gas collecting part;

cutting and removing the gas collecting part; and

forming a polymer coating layer on an outer side portion of the pouch type case receiving the electrode assembly, the outer side portion including a surface exposed due to the cutting and removing of the gas collection part,

wherein the forming of the polymer coating layer is performed by a contact type coating method.

2. The method of manufacturing a pouch type secondary battery of claim 1 , wherein the contact type coating method is performed by using a sponge coating head or a roller coating head.

3. The method of manufacturing a pouch type secondary battery of claim 1 , wherein the pouch type case is formed by attaching an upper sheet and a lower sheet.

4. The method of manufacturing a pouch type secondary battery of claim 3 , wherein each of the upper sheet and the lower sheet includes an inner layer, a metal layer, and an outer layer.

5. The method of manufacturing a pouch type secondary battery of claim 1 , wherein the polymer is a UV curable polymer or a thermosetting polymer.

6. The method of manufacturing a pouch type secondary battery of claim 5 , wherein the UV curable polymer includes at least one selected from the group consisting of an organic isocyanate compound having two or more isocyanate groups and a hydroxyalkyl (meth)acrylate resin modified with a polylactone-based compound.

7. The method of manufacturing a pouch type secondary battery of claim 5 , wherein the thermosetting polymer includes at least one selected from the group consisting of epoxyalkyl (meth)acrylate, allyl glycidyl ether, allyl glycidyl ester, aryl glycidyl ether, aryl glycidyl ester, glycidyl 5-norbornene-2-methyl-2-carboxylate (a mixture of endo- and exo-compounds), 1,2-epoxy-5-hexene, 1,2-epoxy-9-decene, glycidyl (meth)acrylate, glycidyl α-ethyl (meth)acrylate, glycidyl αn-propyl (meth)acrylate, glycidyl αn-butyl (meth)acrylate, methylglycidyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, 4,5-epoxypentyl (meth)acrylate, 5,6-epoxyheptyl (meth)acrylate, and 6,7-epoxyheptyl α-ethylacrylate.

8. The method of manufacturing a pouch type secondary battery of claim 1 , wherein the outer side portion is perpendicular to an extruded surface of an electrode terminal of the electrode assembly.

9. The method of manufacturing a pouch type secondary battery of claim 1 , wherein the outer side portion is horizontal to an extruded surface of an electrode terminal of the electrode assembly.

10. The method of manufacturing a pouch type secondary battery of claim 1 , wherein the polymer coating layer is formed on an entire surface of the outer side portion of the pouch type case, which is an entire surface of the pouch type case.