Abstract: Disclosed herein is a cathode active material including a lithium transition metal oxide based on at least one transition metal selected from a group consisting of Ni, Mn and Co. The lithium transition metal oxide contains fluorine, and most of the fluorine is present on a surface of the lithium transition metal oxide, and at least one metal selected from a group consisting of Mg, Ti, Zr, Al and Fe as well as sulfur (S) are further contained in the lithium transition metal oxide.

Abstract: Disclosed is an electrochemical device, which comprises: (A) a binder comprising polymer particles obtained from the polymerization of: (a) 20-70 parts by weight of a (meth)acrylic acid ester monomer; (b) 20-60 parts by weight of a vinyl monomer; and (c) 0.01-30 parts by weight of an unsaturated carboxylic acid monomer, based on 100 parts by weight of a binder polymer; and (B) electrochemical cells stacked multiply by using the binder, wherein the binder allows electrode active material particles in an electrode to be fixed and interconnected among themselves and between the electrode active material and a collector, and the electrode and a separator that is in contact with the electrode are bonded to each other by way of hot fusion. The binder is also disclosed. The binder has excellent adhesion and thermal bonding characteristics, and thus is useful for an electrochemical device comprising multiply stacked electrochemical cells, and can improve the overall quality of a battery.

Abstract: The present invention relates to a battery cell which is housed in a variable state cell case in which a pole assembly having an anode/separating film/cathode laminate configuration is impregnated with an electrolytic solution. The pole assembly and the cell case are curved together in the same direction at both their ends relative to their central parts in vertical cross section in the axial direction, and they provide a battery cell having a configuration whereby they are curved in a single plane. When such a battery cell is installed in a device having a curved appearance in a single plane or is installed in a location which is curved in a single plane on the inside of a device, there are advantages in that it is efficient, can minimise waste in the space required because of the intimately fined configuration, and it allows the development of devices which have an aesthetically pleasing appearance and which have a diversity of design tailored to consumer preferences.

Abstract: Disclosed is a lithium secondary battery, which is low in capacity loss after overdischarge, having excellent capacity restorability after overdischarge and shows an effect of preventing a battery from swelling at a high temperature.

Abstract: Disclosed is a method for regulating terminal voltage of a cathode during overdischarge. Also disclosed is a lithium secondary battery, which is low in capacity loss after overdischarge, having excellent capacity restorability after overdischarge and shows an effect of preventing a battery from swelling at a high temperature.

Abstract: The present invention relates to a lithium secondary battery comprising an overdischarge-preventing agent. Particularly, the present invention provides a lithium secondary battery comprising an overdischarge-preventing agent having superior effects for an overdischarge test and showing 90% or more capacity recovery after the test, by introducing lithium nickel oxide into a cathode for a lithium secondary battery comprising a lithium transition metal oxide capable of occluding and releasing lithium ions as an overdischarge-preventing agent to supply lithium ions such that irreversible capacity of an anode can be compensated or better, thereby lowering voltage of a cathode first to prevent voltage increase of an anode during the overdischarge test.

Abstract: The present invention relates to a lithium secondary battery comprising an overdischarge-preventing agent. Particularly, the present invention provides a lithium secondary battery comprising an overdischarge-preventing agent having superior effects for an overdischarge test and showing 90% or more capacity recovery after the test, by introducing lithium nickel oxide into a cathode for a lithium secondary battery comprising a lithium transition metal oxide capable of occluding and releasing lithium ions as an overdischarge-preventing agent to supply lithium ions such that irreversible capacity of an anode can be compensated or better, thereby lowering voltage of a cathode first to prevent voltage increase of an anode during the overdischarge test.