NOVELTY - A nonaqueous electrolyte secondary battery (10) consists of a battery element (21) having a cell layer (19) consisting of a positive electrode and a negative electrode laminated through an electrolyte layer (17). The positive and negative electrodes have active-material layers (13,15). The compressive stress during 50% distortion of the electrolyte used for the negative-electrode active-material layer is lower than that of the electrolyte used for the positive-electrode active-material layer.    USE - Nonaqueous electrolyte secondary battery e.g. bipolar secondary battery is used for assembled batteries of vehicles (all claimed) e.g. electric vehicles, hybrid electric vehicles, fuel-cell vehicles, and hybrid fuel-cell vehicles including motorbikes, passenger cars, trucks, buses, light cars, and electric trains, and as non-bipolar type lithium ion secondary battery. Can also be used as power supply of uninterrupted power systems.    ADVANTAGE - The nonaqueous electrolyte secondary battery has excellent reliability and exhibits excellent output characteristics over a long period of time. Peeling at the negative-electrode interface is suppressed and escape of gas emitted in the negative electrode is prevented efficiently. The battery provides vehicles which consume less fuel.    DETAILED DESCRIPTION - A nonaqueous electrolyte secondary battery consists of a battery element having a cell layer consisting of a positive electrode and a negative electrode laminated through an electrolyte layer. The positive electrode has an active-material layer formed on the surface of a collector (11). The negative electrode has an active-material layer formed on the surface of a collector (12). The compressive stress during 50% distortion of the electrolyte used for the negative-electrode active-material layer is lower than that of the electrolyte used for the positive-electrode active-material layer.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional schematic view of a flat non-bipolar type lithium ion secondary battery. (Drawing includes non-English language text)    Nonaqueous electrolyte secondary battery (10)    Collectors (11,12)    Active-material layers (13,15)    Electrolyte layer (17)    Cell layer (19)    Battery element (21)