Nonaqueous electrolytic solution and nonaqueous secondary battery using the same

1. A nonaqueous secondary battery comprising:

a battery case;

a nonagueous electrolytic solution contained within said case, said nonagueous electrolytic solution comprises electrolyte salt LiPF 6 dissolved in an organic solvent, and a silicon compound represented by formula (I):

wherein R 1 represents an alkenyl group having 2 to 10 carbon atoms; R 2 and R 3 each represent an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms; and X represents a halogen atom.

2. The nonaqueous secondary battery according to claim 1 , wherein R 1 is a vinyl group.

3. The nonaqueous secondary battery according to claim 1 , wherein at least one of R 2 and R 3 is a methyl group.

4. The nonaqueous secondary battery according to claim 1 , wherein X is a fluorine atom.

5. The nonaqueous secondary battery according to claim 1 , wherein R 1 is a vinyl group, R 2 and R 3 are each a methyl group, and X is a fluorine atom.

6. The nonaqueous secondary battery according to claim 1 , wherein the organic solvent contains at least one member selected from the group consisting of a cyclic carbonate compound, a cyclic ester compound, a sulfone compound, a sulfoxide compound, an amide compound, an acyclic carbonate compound, an acyclic ether compound, a cyclic ether compound, and an acyclic ester compound.

7. The nonaqueous secondary battery according to claim 1 , wherein the organic solvent contains at least one cyclic carbonate compound and at least one acyclic carbonate compound.

8. The nonaqueous secondary battery according to claim 7 , wherein the cyclic carbonate compound comprises ethylene carbonate.

9. The nonaqueous secondary battery according to claim 7 , wherein the cyclic carbonate compound comprises ethylene carbonate and 1,2-butylene carbonate.

10. The nonaqueous secondary battery according to claim 7 , wherein the acyclic carbonate compound comprises at least one member selected from the group consisting of dimethyl carbonate, ethylmethyl carbonate, and diethyl carbonate.

11. The nonaqueous secondary battery according to claim 7 , which further contains a carboxylic ester compound represented by formula (II):

wherein R represents an alkyl group having 1 to 4 carbon atoms; and n represents 0, 1 or 2.

12. The nonaqueous secondary battery according to claim 1 , wherein the silicon compound represented by formula (I) is present in an amount of 0.05 to 5% by volume.

13. The nonaqueous secondary battery according to claim 1 , further comprising at least 5% by weight of a flame retardant, based on the total organic solvent.

14. The nonaqueous secondary battery according to claim 13 , wherein the flame retardant is one of a halogen and a phosphorus.

15. The nonaqueous secondary battery according to claim 14 , wherein the flame retardant is a phosphoric ester.

16. The nonaqueous secondary battery according to claim 1 , further comprising 10% to 50% by weight of a flame retardant, based on the total organic solvent.

17. The nonaqueous secondary battery according to claim 16 , wherein the flame retardant is one of a halogen and a phosphorus.

18. The nonaqueous secondary battery according to claim 17 , wherein the flame retardant is a phosphoric ester.

19. The nonaqueous secondary battery according to claim 1 , wherein said silicon compound forms a stable polymer film.

20. A nonaqueous electrolytic solution comprising electrolyte salt LiPF6 dissolved in an organic solvent and a non-ionic silicon compound represented by formula (I):

wherein R1 represents an alkenyl group having 2 to 10 carbon atoms; R 2 and R 3 each represent an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms; and X represents a halogen atom.