NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery arranged so that a current interrupt device can be stably operated by generating a larger amount of gas in the event of overcharge.SOLUTION: A nonaqueous electrolyte secondary battery 100 provided by the present invention comprises: an electrode body 20; and an insert material 90 in a winding core part of the electrode body 20, or between the electrode body and a battery case side face. The insert material has a first region part 92 and a second region part 94 which are arranged so that their faces in contact with the electrode body opposed thereto are flush with each other, provided that the deflection temperature of the first region part 92 is 100°C or higher, the temperature being defined by JIS K 7191-2 under the condition of a load of 1.8 MPa, the deflection temperature of the second region part 94 being 80°C or lower. The ratio (Sb/Sa) the area (Sb) of the face of the second region part which is flush with the face of the first region part to the area (Sa) of the face of the first region part which is flush with the face of the second region part is in a range given by: 0.28≤Sb/Sa≤2.1.