Patent ID: 9196895
Filing Date: 2015-11-24
Classification: H01M,Y02E,Y02P,Y02T

Abstract:
1. A sealed secondary battery comprising: an electrode body including a positive electrode and a negative electrode; a battery case accommodating the electrode body; a positive electrode terminal and a negative electrode terminal provided at an outer surface of the battery case and electrically connected to the positive electrode and negative electrode, respectively, of the electrode body; and a current interrupt mechanism that interrupts an electric current when an internal pressure inside the case rises above a predetermined level, wherein the current interrupt mechanism has, between the positive electrode of the electrode body and the positive electrode terminal or between the negative electrode of the electrode body and the negative electrode terminal, a current interrupt valve electrically connected to either of the positive terminal and negative terminal and a rectangular plate-shaped current collecting plate electrically connected to either of the positive electrode and the negative electrode of the electrode body; the rectangular plate-shaped current collecting plate is constituted by a central thin section formed to be relatively thin and a thick portion formed to be relatively thick and located on the circumference of the central thin section, and an annular groove for breaking having a predetermined diameter is formed on the inner side of the central thin section; part of the current interrupt valve is conductively joined to the central thin section of the current collecting plate on the inner side of the annular groove; and the current interrupt valve is configured such that when the internal pressure inside the case rises above the predetermined level, the current interrupt valve is deformed by the internal pressure in a direction of separating from the current collecting plate, and the central thin section of the current collecting plate breaks in a portion of the annular groove, whereby the current interrupt valve following the break of the thin section is separated from the current collecting plate and current interrupt is realized, with the rectangular plate-shaped current collecting plate being designed such that the following conditions (1) and (2) are both fulfilled, where a cross section passing through a central point of the annular groove in the direction parallel to a short side of the rectangular plate-shaped current collecting plate is defined as a reference cross section: (1) a cross section area A (mm (2) a distance P (mm) between the thick section and the annular groove and a cross section area C (mm