NOVELTY - A nonaqueous electrolyte secondary battery (10) consists of electricity-generating element (21) sealed within external covering unit (29). The electricity-generating element has cathode containing cathode active material layer (13) formed on surface of cathode collector (11), anode containing anode active material layer (15) containing aqueous binder formed on surface of anode collector (12), separator (17) which holds an electrolyte, and a gas emission unit to discharge the gas emitted inside the electric power generation element into excessive space (31) inside the exterior unit.    USE - Nonaqueous electrolyte secondary battery e.g. lithium ion secondary battery. Uses include but are not limited to electric vehicles, hybrid electric vehicles, fuel cell vehicles and portable electronic devices, e.g. motorbikes, three-wheeled vehicles, passenger cars, trucks, and buses, light cars and electric trains.    ADVANTAGE - The nonaqueous electrolyte secondary battery has improved lifetime, long-term reliability, battery characteristics e.g. long-term cycle characteristics, performance, vibration resistance, capacity, output characteristics, and charging and discharging efficiency.    DETAILED DESCRIPTION - A nonaqueous electrolyte secondary battery consists of electricity-generating element sealed within external covering unit. The electricity-generating element has a cathode containing cathode active material layer formed on surface of cathode collector, anode containing anode active material layer containing aqueous binder formed on surface of anode collector, a separator which holds an electrolyte, and a gas emission unit to discharge the gas emitted inside the electric power generation element into excessive space inside the exterior unit. The ratio (V2/V1) of volume (V2) of excessive space inside the exterior unit to the volume (V1) of void in power generation element is 0.5-1.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of nonaqueous electrolyte lithium ion secondary battery.    Nonaqueous electrolyte secondary battery (10)    Cathode collector (11)    Anode collector (12)    Cathode active material layer (13)    Anode active material layer (15)    Separator (17)    Electric power generation element (21)    Battery exterior unit (29)    Excessive space inside battery exterior unit (31)