NOVELTY - Non-aqueous electrolyte secondary battery (100) comprises an electrode body (80) comprising a positive electrode (10) and a negative electrode (20), and a non-aqueous electrolyte that are housed in a battery case (50). The battery case is provided with a current interrupt mechanism that activates when pressure inside the case increases. The non-aqueous electrolyte contains cyclohexylbenzene and 4,4'-difluorobiphenyl as gas generating agents that decompose and generate gas when battery reaches overcharged state, and when overall quantity of non-aqueous electrolyte is taken to be 100 mass%.    USE - The aqueous electrolyte secondary battery is useful in power sources for propelling vehicles such as electric vehicles and hybrid vehicles or in portable power sources for personal computers and hand-held devices.    ADVANTAGE - Provided is a non-aqueous electrolyte secondary battery that can achieve both battery characteristics during normal usage and resistance to overcharging at high levels.    DETAILED DESCRIPTION - Non-aqueous electrolyte secondary battery (100) comprises an electrode body (80) comprising a positive electrode (10) and a negative electrode (20), and a non-aqueous electrolyte that are housed in a battery case (50). The battery case is provided with a current interrupt mechanism that activates when the pressure inside the case increases. The non-aqueous electrolyte contains cyclohexylbenzene and 4,4'-difluorobiphenyl as gas generating agents that decompose and generate gas when the battery reaches an overcharged state, and when the overall quantity of the non-aqueous electrolyte is taken to be 100 mass%. Ratio of the content (mass%) of the 4,4'-difluorobiphenyl (W2) relative to the content (mass%) of the cyclohexylbenzene (W1) (W2/W1) is 0.025-0.25.    DESCRIPTION OF DRAWING(S) - The drawing shows a longitudinal sectional view of the non-aqueous electrolyte secondary battery.    Positive electrode (10)    Negative electrode (20)    Battery case (50)    Electrode body (80)    Non-aqueous electrolyte secondary battery (100)