SECONDARY BATTERY AND BATTERY PACK, ELECTRONIC DEVICE, ELECTRIC MOTOR VEHICLE, POWER STORAGE DEVICE AND ELECTRIC POWER SYSTEM

PROBLEM TO BE SOLVED: To provide a secondary battery having a wound electrode body, which is arranged so that the breaking of an electrode can be suppressed while keeping battery characteristics.SOLUTION: A secondary battery comprises: an outer can; and a wound electrode body enclosed in the outer can. In the secondary battery, a winding end portion of a separator located in an outer peripheral portion of the wound electrode body is formed to be longer than a winding end portion of one of positive and negative electrodes which is located further on an outer side in a radial direction. An outermost peripheral portion of the wound electrode body is arranged by winding the separator portion longer than the winding end portion of one of the positive and negative electrodes by one or more rounds and less than four rounds of an external circumference of the wound electrode body.SELECTED DRAWING: Figure 3 【課題】巻回電極体を有する二次電池において、電池特性を維持するとともに電極の破断を抑制する。【解決手段】巻回電極体が外装缶に収容された二次電池において、巻回電極体の外周部に位置するセパレータの巻回終端部が、正極および負極のうち、より外周側に位置する正極および負極のいずれかの巻回終端部よりも長く形成されるようにし、巻回電極体の最外周部が、セパレータの正極および負極のいずれかの巻回終端部よりも長い部分によって巻回電極体の外周の１周以上４周未満巻回されるようにする。【選択図】図３