Lithium secondary battery

Abstract

The present disclosure relates to a lithium secondary battery. More specifically, the lithium secondary battery of the present disclosure includes a cathode, an anode, a separator interposed between the cathode and the anode, and a non-aqueous electrolyte solution, wherein the non-aqueous electrolyte solution includes an ionizable lithium salt and an organic solution, and includes, based on 100 parts by weight of the non-aqueous electrolyte solution, (a) 1 part by weight to 10 parts by weight of a compound containing a vinylene group or vinyl group, and (b) 0.1 parts by weight to 10 parts by weight of a dinitrile-based ether compound of a particular structure, and the cathode includes a cathode active material including a mixture of a first cathode active material Li x CoO 2 (0.5<x<1.3) and a second cathode active material Li x M y O 2 (M is Ni 1-a-b Mn a Co b (0.05‰¤a‰¤0.4, 0.1‰¤b‰¤0.4, 0.4‰¤1-a-b‰¤0.7) in which x+y=2 and 0.95‰¤x‰¤1.05. The lithium secondary battery of the present disclosure has a high capacity, and remarkably suppresses a swelling phenomenon at high temperature of the battery.

Description

technical field [0001] The present invention relates to a lithium secondary battery that ensures excellent safety and suppresses swelling at high temperatures. [0002] This application claims priority from Korean Patent Application No. 10-2013-0116487 filed in Korea on September 30, 2013, the disclosure of which is hereby incorporated by reference into this specification. [0003] In addition, this application also claims the priority of Korean Patent Application No. 10-2014-0131487 filed in Korea on September 30, 2014, the disclosure content of which is hereby incorporated by reference into this specification. Background technique [0004] In recent years, people have paid more and more attention to energy storage technology. As energy storage technology has expanded into mobile phones, video cameras, notebook computers and even electric vehicles, the need for high-energy-density batteries to power electronic devices continues to increase. According to demand, extensive ...

AI Technical Summary

Problems solved by technology

[0007] However, there is a problem that when a lithium secondary battery is stored at a high temperature in a fully charged state, the lithium transition metal oxide or composite oxide used as a positive electrode active material becomes thermally unstable

[0008] In addition, organic solvents currently widely used as non-aqueous electrolytes include: ethylene carbonate, propylene carbonate, dimethoxyethane, γ-butyrolactone, N,N-dimethylformamide, tetrahydrofuran or Acetonitrile, in general, for these organic solvents, when stored at a high temperature for a long period of time, the stable structure of the battery can be deformed due to gas generation due to the oxidation of the electrolyte; or when internal heat generation occurs due to overcharge or overdischarge, In severe cases, it will cause internal short circuit, which will cause the battery to burn or explode

[0009] Therefore, in order to solve these problems, various studies have been made, but so far, no effective solution has been proposed, especially, with the current increase in demand for high-performance lithium secondary batteries, solutions thereof are urgently needed

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