| 摘要 |
Provided is a secondary battery that prevents short-circuits between a positive electrode and negative electrode by means of an insulation member, suppresses deformation and enlargement of the volume of a battery element, and has high reliability and electrical characteristics. This secondary battery includes a battery element in which a positive electrode 1 and a negative electrode 6 are laminated alternately with a separator 20 therebetween. The positive electrode 1 and negative electrode 6 include current collectors 3, 8 and active materials 2, 7. Active material 2, 8 coated portions and uncoated portions are provided on each surface of the current collectors 3, 8, and the active materials 2, 7 have a thin portion having a small thickness. The charge capacity ratio A/C of the negative electrode 6 and positive electrode 1 facing each other at an outer edge portion that includes the thin portion is greater than the charge capacity ratio A/C of the negative electrode 6 and positive electrode 1 facing each other further toward the center than the outer edge portion. |
