Secondary battery comprising insulator and reinforcing filler

1. A secondary battery having a structure in which a jelly-roll having a cathode/separator/anode structure is mounted in a cylindrical battery case and a plate-shaped insulator is mounted on top of the jelly-roll,

wherein the insulator has a porous structure in which a plurality of pores communicate in a longitudinal direction, or in traverse and longitudinal directions, and further comprises a reinforcing filler to improve mechanical strength, and

wherein the reinforcing filler has a granular or fibrous shape.

2. The secondary battery according to claim 1 , wherein the pores are formed over the entire surface of the insulator.

3. The secondary battery according to claim 1 , wherein the insulator comprises an electrical insulating polymer resin or an electrical insulating polymer composite.

4. The secondary battery according to claim 3 , wherein the polymer resin is at least one selected from the group consisting of polyethylene (PE), polypropylene (PP), polybutylene (PB), polystyrene (PS), polyethylene terephthalate (PET), natural rubbers and synthetic rubbers.

5. The secondary battery according to claim 1 , wherein the insulator has a thickness of 0.1 mm to 0.5 mm.

6. The secondary battery according to claim 1 , wherein the insulator comprises an opening to enable pass-through of electrode terminals.

7. The secondary battery according to claim 1 , wherein the battery is a lithium secondary battery.

8. A device comprising the secondary battery according to claim 1 as a power source.

9. The device according to claim 8 , wherein the device is selected from a cellular phone, a portable computer, an electric bike (E-bike), an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle and a power-storage device.

10. The secondary battery according to claim 1 , wherein the pores have a size of 1 μm to 100 μm.