1DESCRIPTIONNON-AQUEOUS ELECTROLYTE SOLUTION FOR LITHIUM SECONDARY BATTERY AND LITHIUM SECONDARY BATTERYINCLUDING THE SAME5TECHNICAL FIELDCross-reference to Related Applications[0001]This application claims the benefit of Korean Patent ApplicationNos.2017-0156345, filed onNovember22, 2017,and 2018-0145685, filed onNovember 22, 2018,in the Korean 10Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.TechnicalField[0002]The present invention relates to anon-aqueouselectrolyte solution for a lithium secondary batterywhich 15may suppress gas generationand a lithium secondarybattery includingthesame.BACKGROUND ART[0003]In line with miniaturization,lightweight, thin profile, and portable trendsinelectronicdevices according 20to the development of information and telecommunications industry, the need for high energy density lithium secondary batteries used as power sources of such electronic devices has increased.[0004]Lithium secondary batteries, specifically, lithium 25
2ion batteries (LIB), as batteries that may best meet the need, have been adopted as power sources of many portable devices due to high energy density and ease of design.[0005]Recently, a lithium secondarybattery, which may maintainexcellent performance not only at room temperature5but also in a more severe outside environmentsuch as a high-temperature or low-temperature environment, is required as the range of the lithium secondary batteries used has expanded from conventionalsmall electronic devices to large electronic devices, cars, or smart grids.10[0006]A lithium secondary battery currently used is composed of a carbon-based negative electrode capable of intercalating and deintercalating lithium ions, a positive electrode formed of lithium-containing transition metal oxide, and a non-aqueous electrolyte solution in which an 15appropriate amount of a lithium salt is dissolved in a mixed carbonate-based non-aqueous organicsolvent, wherein charge and discharge may be possible while a phenomenon is repeated in whichlithium ions, which are deintercalated from the positive electrode by charging, are intercalated into the 20carbon-based negative electrodeand again deintercalated during discharging.[0007]An increase in driving voltage of the lithium secondary battery is the most efficient and easy methodamong methods for achieving a high capacity and high output lithium 25
3secondary battery.[0008]However, since a reaction of an electrolyte with an electrode active material is increased when the driving voltage is increased, thermal durability is reduced at high temperatures and a large amount ofgas is generated, and thus, 5there is a limitation in that a cell swelling phenomenon occurs. This phenomenon is particularly severewhen the driving voltage of the battery is a high voltage of 4.35 V or more.[0009]Thus, in order to develop a high capacity and high 10output lithium secondary battery, there is a need to develop a technique capable of effectively controlling an interfacial reaction of the electrolyte solution and the electrode even at a high driving voltage.[0010]Prior Art Document15[0011]Japanese Patent No. 3911870DISCLOSURE OF THE INVENTIONTECHNICAL PROBLEM[0012]An aspect of the present invention providesa non-aqueous electrolytesolution for a lithium secondarybattery 20which may effectively suppressgas generation by forming a stable ion conductive film on the surface of a negative electrode.[0013]Another aspect of the presentinvention provides alithium secondarybatteryin whichcell swellingis lowby 25
4includingthe above-described non-aqueous electrolyte solution for a lithium secondarybattery.TECHNICAL SOLUTION[0014]According to an aspect of the present invention,there is provided anon-aqueous electrolyte solution for a 5lithium secondary batteryincluding:[0015]a lithium salt,[0016]anon-aqueoussolventincluding a carbonate-based solvent and propyl propionate,and[0017]a compound represented by Formula 1 below.10[0018][Formula 1][0019]In Formula 1,[0020]R1and R2are each independently hydrogenor asubstituted or unsubstitutedalkyl group having 1 to 6carbon 15atoms.[0021]Thenon-aqueoussolventmay include the carbonate-based solvent and thepropyl propionate in a weight ratio of 2:8 to 4:6.20[0022]The carbonate-based solvent may includeethylene carbonate.
5[0023]Also, thenon-aqueoussolventmay further include ethyl propionate.[0024]Furthermore, the compound represented by Formula 1may be selected from thegroup consisting ofcompounds representedby Formulae 1a to 1cbelow.5[0025][Formula 1a][0026][Formula 1b][0027][Formula 1c]10[0028]Specifically, the compound represented by Formula 1maybe selected from thegroup consisting ofthe compounds representedby Formulae 1b and 1c.15
6[0029]The compound represented by Formula 1 may be includedin an amountof 0.01 wt% to 11.5wt%, for example, 0.1 wt% to 10 wt% based on a totalweight of thenon-aqueous electrolyte solution.[0030]According to another aspect of the present invention,5there is providedalithium secondary battery includingthe non-aqueous electrolyte solution for a lithium secondary batteryof thepresent invention.ADVANTAGEOUS EFFECTS[0031]According to the presentinvention,a non-aqueous 10electrolyte solution for a lithium secondarybattery may suppress gas generation and cell swelling during operationat a high voltage of 4.35 V or more and during high-temperature storage by using propyl propionate, as a non-aqueous solvent, in an amount of60 wt% to 80 wt% to reduce an amount ofa 15carbonate-based solvent used which is sensitive to side reactions. Also, since the non-aqueous electrolyte solution for a lithium secondarybatteryof the presentinvention may form a stableion conductive film on the surface of a negative electrode by including a compound containing both of 20a propargyl group known to have metal ion adsorbabilityand an imidazole group effective for solid electrolyte interface (SEI)formationas an additive, gas generation due to a side reaction between a positive electrode and an electrolyte may be suppressed, and thus, the cell swelling may be 25
7significantlyreduced.BRIEF DESCRIPTION OF THE DRAWINGS[0032]The following drawings attached to the specification illustrate preferred examples of the present invention by example, and serve to enable technical concepts of the 5present invention to be further understood together with detailed description of the invention given below, and therefore the present invention should not be interpreted only with matters in such drawings.[0033]FIG. 1 is a graph illustratingthe results of cycle 10life characteristics evaluation of lithium secondary batteriesaccordingto Experimental Example 1 ofthe present invention.MODE FOR CARRYING OUT THE INVENTION[0034]Hereinafter, the present invention will be described 15in more detail.[0035]Itwill be understood that words or terms used in the specification and claims shall not be interpreted as the meaning defined in commonly used dictionaries, and it will be further understood that the words or terms should be 20interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the technical idea of the invention, based on the principle that an inventor may properly define the meaning of the words or terms to best explain the invention.25
8[0036]In the presentspecification, it will be further understood that the terms “include,” “comprise,” or "have" when used in this specification, specify the presence of stated features, numbers, steps, elements, or combinations thereof, but do not preclude the presence or addition of one 5or more other features, numbers, steps, elements, or combinations thereof.[0037]In the presentspecification, the expression “%”denotes wt% unless otherwise indicated explicitly.10[0038]Electrolyte for Lithium Secondary Battery[0039]First, a non-aqueous electrolyte solution for a lithium secondary batteryaccording to the present invention will be described.[0040]The non-aqueous electrolyte solution for a lithium 15secondary batteryofthe present invention includes:[0041]a lithium salt,[0042]anon-aqueoussolventincluding a carbonate-based solvent and propyl propionate,and[0043]a compound represented by Formula 1 below.20[0044][Formula 1]

Anon-aqueous electrolyte solution for a lithium secondary battery, the non-aqueous electrolytesolution comprising:5a lithium salt,anon-aqueoussolventincluding a carbonate-based solvent and propyl propionate,anda compound represented by Formula 1:[Formula 1]10wherein, in Formula 1,R1and R2are each independently hydrogenor asubstituted or unsubstitutedalkyl group having 1 to 6carbon atoms.152.The non-aqueous electrolytesolution for a lithium secondary batteryof claim 1, whereinthenon-aqueoussolventcomprises the carbonate-based solvent and thepropyl propionate in a weight ratio of 2:8 to 4:6.203.The non-aqueous electrolytesolution for a lithium
54secondary batteryof claim 1,whereinthe carbonate-based solvent is ethylene carbonate.4.The non-aqueous electrolytesolution for a lithium secondary batteryof claim 1,whereinthenon-aqueoussolvent5further comprises ethyl propionate.5.The non-aqueous electrolytesolution for a lithium secondary batteryof claim 1,whereinthecompound represented by Formula 1isselected from thegroup 10consisting ofcompounds representedby Formulae 1a to 1c:[Formula 1a][Formula 1b]15[Formula 1c]
55.6.The non-aqueous electrolytesolution for a lithium secondary batteryof claim 5,whereinthecompound represented by Formula 1isselected from thegroup 5consisting ofthe compounds representedby Formulae 1b and 1c.7.The non-aqueous electrolytesolution for a lithium secondary batteryof claim 1,wherein the compound represented by Formula 1isincludedin an amountof 0.01 wt% 10to 11.5wt% based on atotalweightof thenon-aqueous electrolyte solution.8.The non-aqueous electrolytesolution for a lithium secondary batteryof claim 1, wherein the compound 15represented by Formula 1isincludedin an amountof 0.1 wt% to 10wt% based on atotalweight of thenon-aqueous electrolyte solution.9.A lithium secondary batterycomprisingthe non-aqueous 20electrolyte solutionfor a lithium secondary batteryof claim