Abstract: Disclosed herein is a unit cell for a lithium ion secondary battery, which includes an electrode laminate formed in such a manner that a plurality of unit structures are stacked, each of which includes and least one electrode and at least one separation layer; and at least one conductive sheet layer located between certain layers in the electrode laminate and electrically connected to an electrode lead. The conductive sheet layer of the unit cell for the lithium ion secondary battery rapidly conducts current to the outside or generates heat in quantity smaller than the quantity of heat generated in positive and negative electrodes when short-circuit occurs due to a physical or electrical impact applied to the battery. Accordingly, it is possible to reduce the risk of firing or explosion due to the physical or electrical impact to improve the safety of the lithium ion secondary battery.

Abstract: A pouch type lithium secondary battery includes a crude cell equipped with electrode leads and electrode tabs, a battery case for sealing the crude cell, and insulating materials provided on an inner surface of the battery case in which the electrode leads and the electrode tabs are disposed. In a method of fabricating a pouch type lithium secondary battery comprising a crude cell equipped with electrode leads and electrode tabs, and a battery case for sealing the crude cell, the battery case is comprised of a first receiving portion for receiving the crude cell and a second receiving portion for receiving the electrode leads. The method includes the steps of processing insulating materials on an inner surface of the second receiving portion, inserting the crude cell into the battery case, and sealing the battery case.

Abstract: The present invention discloses a crude cell for a large secondary battery comprising unit cells alternately stacked in the fold/fold type or a crude cell for a large secondary battery comprising unit cells wound and stacked in the jelly roll type, each unit cell having an anode, a cathode and a separator, in which a polymer film is inserted in the crude cell to support the crude cell. According to the present invention, it is possible to prevent structural distortion caused by external impact and self reaction of the crude cell by firmly supporting the crude cell. Consequently, it is possible to prevent short of the anode and the cathode in the crude cell by electrical connection and to improve interfacial properties of the anode, the cathode and the separator.