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

PROBLEM TO BE SOLVED: To maintain battery characteristics and suppress an electrode from being broken, in a secondary battery having a wound electrode body.SOLUTION: In a secondary battery including a wound electrode body stored in an outer can, a wound terminal part of a separator positioned at a periphery of the wound electrode body is formed to be longer than a wound terminal part of one of a positive electrode and a negative electrode positioned on a more outer peripheral side between the positive electrode and the negative electrode, and an outermost peripheral part of the wound electrode body is wound by one turn or more and less than four turns of the outer periphery of the wound electrode body by a part of the separator longer than the wound terminal part of one of the positive electrode and the negative electrode. 【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