Nonaqueous electrolyte secondary battery

The secondary battery includes: an electrode body including an electrode plate; a square exterior body in which the electrode body is accommodated; a sealing plate; the electrode terminal is arranged on the sealing plate; a first current collector disposed between the electrode body and the sealing plate and connected to the electrode terminal; a second current collector disposed between the electrode body and a side wall of the square exterior body and connected to the first current collector; and a tab group formed by stacking a plurality of tabs extending from the electrode plate toward the side wall side, the tab group being connected to the second current collector. The tab group is connected to the second current collector, and is bent parallel to the side wall on the connection portion side connected to the second current collector. And the curvature radius of the first arc part of the root part of each tab is greater than that of the second arc part of the front end part of each tab. 二次电池包括：电极体，所述电极体包