NOVELTY - A nonaqueous electrolyte secondary battery consists of positive electrode plate, negative electrode plate (14), porous separator (15) interposed between plates and electrolyte (16) solution containing cyclohexyl benzene or its derivative. The positive electrode plate (13) is obtained by forming positive electrode mixture layer containing mixed active material of layered lithium complex oxide and spinel lithium-manganese oxide on collector. The mixture density and porosity of positive electrode mixture layer is 2.3-2.75 g/cm3 and 34-46%, respectively.    USE - Nonaqueous electrolyte secondary battery. Uses include but are not limited video equipment, notebook personal computer, personal digital assistant, video camera, digital camera, mobile telephone, electrical storage device for fixation of electrical storage devices for motor vehicle and railways.    ADVANTAGE - The nonaqueous lithium ion secondary battery has excellent overcharge suppression function, battery performance, balance between discharge characteristics and durability, and is safe.    DETAILED DESCRIPTION - A nonaqueous electrolyte secondary battery consists of positive electrode plate, negative electrode plate, porous separator interposed between plates and electrolyte solution containing cyclohexyl benzene or its derivative. The positive electrode plate is obtained by forming positive electrode mixture layer containing mixed active material of layered lithium complex oxide and spinel lithium-manganese oxide on collector. The negative electrode plate is obtained by forming negative electrode mixture layer containing active material and carbon-containing material on collector. The mixture density and porosity of positive electrode mixture layer is 2.3-2.75 g/cm3 and 34-46%, respectively.    DESCRIPTION OF DRAWING(S) - The drawing shows schematic view of nonaqueous lithium ion secondary battery.    Positive electrode plate (13)    Negative electrode plate (14)    Separator (15)    Electrolyte (16)    Electrode group (17)