NOVELTY - The secondary battery has a winding electrode portion (80) with positive and negative electrode sheets (10,20) wound with the separator sheets (40A,40B). The porous heat-resistant layers (44A,44B) are formed in the surface of the base materials (42A,42B) of separator sheets. The separator base-material exposure portions (46A,46B) are arranged in the position to contact with the positive electrode active material layer non-formation portion (16) or negative electrode active material layer non-formation portion (26), and are formed in the sheet longitudinal direction.    USE - Secondary battery such as lithium secondary battery and nickel-hydrogen battery of assembled battery for vehicle (all claimed) such as a plug-in hybrid motor vehicle (PHV), hybrid vehicle (HV) and electric vehicle (EV). Can also be used in personal computer and portable terminal.    ADVANTAGE - The generation of the shift in the winding electrode portion due to the fall of the frictional force can be prevented even in the case where the separator sheet having the porous heat-resistant layer, without disturbing the connection of the terminal for external connection in the electrode active material layer non-formation portion. The rigidity of the winding electrode portion can be maintained and the fall of productivity can be prevented. The characteristics of the battery can be improved.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) an assembled battery; and    (2) a vehicle.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the structure of winding electrode portion of secondary battery.    Positive electrode sheet (10)    Positive electrode active material layer non-formation portion (16)    Negative electrode sheet (20)    Negative electrode active material layer non-formation portion (26)    Separator sheets (40A,40B)    Base materials (42A,42B)    Porous heat-resistant layers (44A,44B)    Separator base-material exposure portions (46A,46B)    Winding electrode portion (80)