Secondary battery having electrode with self cutting part to be destructed on application of over-current

摘要

Disclosed herein is a plate-shaped secondary battery used as a unit cell for middle- or large-sized battery pack, the secondary battery having an electrode assembly, which can be charged and discharged, mounted in a sheet-shaped battery case including a metal layer and a resin layer in a sealed state, the electrode assembly having electrode terminals protruding outside a sealing part of the battery case, wherein at least one of the electrode terminals is provided at a position spaced a predetermined distance from the sealing part with a self cutting part having a vertical sectional area less than that of the remaining part of the at least one electrode terminal such that the self cutting part can break first when overcurrent flows in the secondary battery.

主权项

1. A plate-shaped secondary battery for middle- or large-sized battery pack, the secondary battery, comprising:
a sheet-shaped battery case having a sealing part and including a metal layer and a resin layer; and an electrode assembly, which can be charged and discharged, the electrode assembly mounted with an electrolyte in the sheet-shaped battery case in a sealed state, and having electrode terminals, the electrode terminals including a cathode terminal having an exposed portion protruding outside the sealing part of the battery case, wherein at least one of the electrode terminals is provided at a position spaced a predetermined distance from the sealing part with a self cutting part having a vertical sectional area less than a vertical sectional area of a remaining part of the at least one electrode terminal such that the self cutting part can break first when overcurrent flows in electrode assembly, and the self cutting part is located outside the battery case such that the battery case and sealing part are located between the self cutting part and the electrode assembly, wherein the self cutting part is formed in the cathode terminal, wherein thin resin film-shaped sealing members are attached to coupling regions between the battery case and the electrode terminals, wherein an endothermic layer having high latent heat during a change of phase is formed only on the exposed portion of the cathode terminal between the sealing part and the self cutting part, wherein the predetermined distance is defined as a distance at which the self cutting part can break before heat generated from the self cutting part is transmitted to the sealing part of the battery case, such that the sealing part is separated, when the overcurrent flows in the electrode assembly, and wherein the battery case is made of a laminate sheet including the metal layer and the resin layer.