Non-aqueous electrolyte secondary battery and method for producing same

1. A non-aqueous electrolyte secondary battery comprising:

a positive electrode;

a negative electrode;

a non-aqueous electrolyte solution comprising a non-aqueous solvent and a supporting salt;

a case to house the positive electrode, the negative electrode and the non-aqueous electrolyte solution;

a conduction pathway formed to allow conduction between at least one of the electrodes and an outer terminal exposed outside the case;

a current-interrupting device to cut off the conduction pathway at a predetermined increase in the internal pressure of the case;

an overcharge-reactive compound; and

overcharge-reactive multimers including dimers to higher-order multimers formed by polymerization of the overcharge-reactive compound, wherein

the overcharge-reactive multimers are present in a larger amount by mole than the overcharge-reactive compound remaining unpolymerized at or near the positive electrode, and

the current-interrupting device is activated and cuts off the conduction pathway by gas generated by the reaction of the overcharge-reactive compound and the overcharge-reactive multimers when an overcharged state is reached.

2. The non-aqueous electrolyte secondary battery according to claim 1 , wherein the overcharge-reactive multimers primarily comprise dimers to decamers of the overcharge-reactive compound.

3. The non-aqueous electrolyte secondary battery according to claim 1 , wherein the positive electrode comprises a polymerization initiator.

4. The non-aqueous electrolyte secondary battery according to claim 3 , wherein the polymerization initiator is an azo-based polymerization initiator.

5. The non-aqueous electrolyte secondary battery according to claim 1 , wherein the overcharge-reactive compound is at least one species selected from a group consisting of branched-chain alkylbenzenes, cycloalkylbenzenes, biphenyls, terphenyls, diphenyl ethers and dibenzofurans.

6. A method for producing a non-aqueous electrolyte secondary battery, the method comprising:

obtaining a positive electrode comprising a positive electrode material layer and a polymerization initiator, wherein the polymerization initiator is added in an amount of 100 ppm to 1000 ppm by mass in the positive electrode material layer,

obtaining a negative electrode comprising a negative electrode material layer,

obtaining a non-aqueous electrolyte solution comprising a non-aqueous solvent, a supporting salt and an overcharge-reactive compound,

obtaining a case to house the positive electrode, the negative electrode and the non-aqueous electrolyte solution,

constructing a current-interrupting device to cut off a conduction pathway allowing conduction between at least one of the positive electrode and the negative electrode and an outer terminal exposed outside the case when the internal pressure of the case is increased to a predetermined level,

supplying the non-aqueous electrolyte solution to the positive electrode, and

polymerizing the overcharge-reactive compound to form overcharge-reactive multimers including dimers to higher-order multimers at or near the positive electrode.

7. The method according to claim 6 , wherein the overcharge-reactive multimers primarily comprise dimers to decamers of the overcharge-reactive compound.

8. The method according to claim 6 , wherein after the non-aqueous electrolyte solution is supplied to the positive electrode, the non-aqueous electrolyte solution supplied is heated at a temperature of 50° C. to 100° C. to polymerize the overcharge-reactive compound.

9. The method according to claim 6 , wherein as the polymerization initiator, an azo-based polymerization initiator is used.

10. The method according to claim 6 , using, as the overcharge-reactive compound, at least one species selected from a group consisting of branched-chain alkylbenzenes, cycloalkylbenzenes, biphenyls, terphenyls, diphenyl ethers and dibenzofurans.

11. A vehicle comprising the non-aqueous electrolyte secondary battery according to claim 1 .