Patent ID: 9741994
Date: 2017-08-22
CPC Classifications: H01M,Y02E

Claim:
1. A rectangular secondary battery comprising a flat electrode group, a battery can housing the electrode group, a battery lid closing an opening of the battery can, an external terminal provided to the battery lid, and a current breaking mechanism interposed in the middle of a current path electrically connecting the external terminal and the electrode group and breaking the current path by a rise of battery internal pressure, wherein the current breaking mechanism includes: a connection electrode arranged inside the battery lid and electrically connected to the external terminal and a conductive plate bonded to the connection electrode and deformed by the rise of the battery internal pressure, a crimp portion composed of the external terminal crimped around an opening of the connection electrode and fixed to an insulator attached to an underside of the battery lid, wherein the crimp portion protrudes beneath the battery lid and above the conductive plate, the connection electrode includes a planar portion having a through hole in communication with the outside of the battery, and the conductive plate includes a dome-shaped diaphragm portion in a non-deformed state protruding away from the crimp portion, and a ring-shaped flange portion extending radially outward from an outer peripheral portion of the diaphragm portion, the diaphragm portion covering the through hole of the connection electrode, and the flange portion being bonded to the planar portion of the connection electrode.