| 摘要 |
PROBLEM TO BE SOLVED: To prevent the frictional force of a separator sheet and a positive/negative electrode sheet from lowering, when using a separator sheet having a porous heat resistant layer.SOLUTION: A secondary battery includes a wound electrode body (80) formed by winding a positive electrode sheet (10) and a negative electrode sheet (20) together with separator sheets (40A, 40B). On at least one surface of the base materials (42A, 42B) of the separator sheets, porous heat resistant layers (44A, 44B) are formed, and at both ends thereof in the width direction, separator base material exposed parts (46A, 46B) not having the porous heat resistant layer are formed in the sheet length direction, at positions capable of coming into contact with a positive electrode active material layer non-forming part (16) or a negative electrode active material layer non-forming part (26) facing each other. |
