*NOTMCE *
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`JPO and INPIT are not responsible far any damages caused by the use of this teanaiatian.
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`1. This document has been translated by computer. Se the transiation may not sefiect ine original precisely.
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`2°" shows a word which cannot he transisted.
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`3, in the drawings, any words are not franstated,
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`Publication Number
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`JPZO T40959564,
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`Bibliography
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`(18) [Publication country] JP
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`(12) [Kind of official gazette] A
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`(17) [Publication number} 2014035956
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`(43) [Date of publication of application] 20740224
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`(54) [Title of the invention] NONAQUEOUS ELECTROLYTE AND. NONAQUEOUS
`
`ELECTROLYTE SECONDARY BATTERY USING THE SAME
`
`(51) international Patent Classification]
`
`HOIM 10/0567
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`HOIM 10/052
`
`(2010.01)
`
`(2010.01)
`
`[Fi]
`
`HOM 10/60
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`HOIM 10/06
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`112
`
`402
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`(21) {Application number] 2012177498
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`(22) [Filing date] 20720809
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`(71) [Applicant]
`fName] MITSUBISHI CHEMICALS CORP
`
`(72) {inventor
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`fFull mame}? OHASHI YOICHI
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`iFull name] KOTADO MINORU
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`iTheme code {reference)}
`5HOZ9
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`iF-term {reference} ]
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`SHOZGAJO2
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`SHOZSAIOS
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`SHOZ9AK04
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`

`

`SHOZSAKOS
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`SHOZGAKOS
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`SHOZSALOS
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`SHOZSALOG
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`SHOZSAL07
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`SHOZSALTI
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`SHOZSAMO1
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`SHOZSAMO2
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`SHOZSAMOS
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`SHOZSAMO4
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`SHOZ9AMOS
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`SHOZSAMOG
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`SHOZSAMO?
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`SHO29HIO1
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`SHOZSHIO2
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`Abstract
`
`(57) [Overview]
`
`PROBLEM TO BE SOLVED: To provide: a nonaqueous siectrolyte capable of improving
`
`load characteristics and cycle characteristics in a nonaqueous electrolyte secondary
`
`hattery; and a nonaqueous efectrolyie secondary battery using the nonaqueous
`
`electrolyte.
`
`SOLUTION: A nonaqueous electrolyte is used for a nonaqueous electrolyte secondary
`battery including a positive electrode containing a positive electrode active material
`
`capable of absorbing/desorbing metal
`
`ions, and a negative electrode containing a
`
`negative electrode active material capable of absorbing/desorbing metal
`
`ions. The
`
`nonaqueous electrolyte contains a specific anhydride compound and a carboxylic acid,
`
`and the cantent of the carboxylic acid is 0.00001 mass%: or more and less than 0.014
`
`mass% with respect to the total amount of the nonacueous electrolyte.
`
`
`Claim
`
`{Patent Claims]
`iClaim 4]
`
`is a nonaqueous electolyle used for a sonaqueaus electrolytic solution secondary
`It
`battery provided with the positive electrode which has the positive active material which
`
`may occlude and emit metal ion, and the anode which has the negative electrode active
`
`

`

`material which may occlude and emit metal ion,
`
`The composition contains a compound represented by general formula {1} and a4
`
`carboxylic acid,
`
`The nonaqueous electralyte solution is charactertzed in that the content of the carbaxylic
`
`acid is 0.00001 mass% or more and less than 0.01 mass% with respect fo the total
`
`amount of the nonaqueous electrolyte solution.
`
`[Chemical formula 1]
`
`(in the formula, each of fhe symbols represents a hydrogen atam, a fluorme atom, an
`
`alkyi group, an alkenyl group, an group, or an aryl group.) R1.R2,RORd RSRS
`
`Claim 2]
`
`The nonaqueous electrolyte solution according to claim 1, wherein the content of the
`
`carboxylic acid Is 0.0001%by mass or more and less than 0.01% by mass Dased on the
`
`total amount of the nonaqueous electrolyte solution.
`
`Claim 3]
`
`The nonaqueous electrolytic solution according to claim tor 2, wherein the carboxylic
`
`acid is represented by the following general formula (2).
`
`{Chemical formula 2]
`
`(R 1, R 2, and R 3 each independently represents a hydrogen atom, a flucrine atom, an
`
`alky] group, an alkenyl group, an alkynyl group, or an aryl group.
`
`iClaim 4]
`The nonaqueous electrolyte solution according to any one of claims 1 fo 3, wherein the
`
`compound represented by the general formula (1) is a compound selected from the
`
`following group of compounds (compounds A te Dy:
`
`{Chemical formula 3]
`
`Claim 3]
`This composition contains at least one kind selected fram a group consisting of a cycle
`
`carbonate having a carbon-carbon unsaturated band, a cyclic carbonate having a
`
`

`

`halogen atom, a nitrile, an isocyanate, a cyclohexylbenzene, a t-amylbenzene, 2 t-
`
`butylbenzene, and a sulfonic ester.
`
`The non-aqueous electralyte solution according to any one of claims 7 ta 4. wherein the
`
`nonaqueous electrolyte solution is a nonaqueous electrolyte solution.
`iClaim 6]
`
`The nonaqueous electrolyte solution according to any one of claims 7 to 5, wherein the
`
`nonaqueous electrolyte contains at least one of nitries or isacyanates.
`iClaim 7]
`
`is a nonaqueous electrolytic solution secondary battery provided with the pasitive
`It
`electrode which has the positive active material which may occlude and emit metal ion,
`
`and the anode which has the negative electrode active material which may occlucie and
`
`emit metal ion,
`
`A nonaqueous electrolyie secondary battery cornprising the nonaqueous electralyie
`
`according to any one of claims { to 6. 2.
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`Description
`
`[Detailed description of the invention}
`
`fTechnical flelc]
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`{0004}
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`The present invention relates to a nonaquecus electrolyte and a nonaqueous electratyte
`
`secondary battery using the same. 2.
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`iBackground of the invention]
`
`{0002}
`
`With the rapid progress in an electronic device, the demand to high-capacity-izing to a
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`rechargeable battery is high, and nonaqueous electrolyte cells, such as a nickel-
`
`cacinium battery and a rechargeable ithium-ian battery with an energy density high
`
`compared with a nickel bydoride battery, are used widely, and it inquires actively.
`
`An electrolytic solution used in a nonaqueous electrolyte battery usually consists mainly
`
`of an electrolyte and a nonaqueous solvent. As an electrolysis solution of a rechargeable
`
`lithium-ion battery, they are high dielectric constant solvents, such as ethylene carbonate
`
`and propylene carbonate, about electrolytes, such as LIPF6,LIBF4,LIN(CF3SO2) 2, A
`
`nonaqueous electrolyte solution is used which is dissolved in a mixed solvent of a law
`
`viscosity solvent such as dimethyl carbonate, diethyl carbonate, and methy! ethyl
`
`carbonate. Also, a gel electrolyte in which an electratytic solution as cescribed above is
`
`contained in a matrix polymer and brought into a gel state is used.
`
`

`

`{OO03}
`
`In a lithium ion secondary battery, when charging and discharging are repeated, an
`
`electrolyte decomposes on an electrode, and ceterioration of a material constituting a
`
`battery occurs, and thus a capacity of a battery is recliced in the battery 2. In sarne cases,
`
`there is a possibility that the safety against swelling, ignition, explosion, explosion, and
`the like is reduced.
`
`Until now, the method of improving the battery characteristic of a rechargeable lithium-
`
`ion batteryis proposed by making an acid anhydride contain into nonaqueaus electrolyte.
`
`For example, Patent Docurnent
`
`3 proposes a nonaqueous electrolytic solution
`
`comprising a nonaqueous sclvent containing a carboxylic anhydride having a carbon-
`carbon unsaturated bond and / or an aromatic ring in a molecule and an electrolyte. As
`
`a result, jeakage current when the coin cell using the Li metal and the natural graphite
`
`negative electrode is kept at 60 “ C.in the charged state is suppressed. However, Patent
`
`Document 1 does not describe carboxylic acid in a nonaqueous electrolyte solution, and
`
`dogs not suggest that there is a possibility that a cycle characteristic deteriorates due to
`
`@ carboxylic acid in a nonaqueous electrolyte solution and a specific effect when a
`
`specific acid anhydride and a carboxylic acid comst at a certain content.
`
`(004)
`
`In addition, in Patent document 2, a nonaqueous solvent, an electrolyte, a nonaqueous
`
`soivent, a fluoride, and a nonaqueous solvent and an electrolyte are mixed in an amount
`
`of 0.07% by weight based on the fotal amount of the nonaqueous solvent and the
`
`electrolyte. 0.0005-0.7
`
`A nonaqueous electrolytic solution containing 4.0% by weight of a carboxyl group ors
`
`compound having a carboxylic anhydride graup has been proposed. Accordingly, a coin
`cell using a natural graphite negative electrode and a LiICaG 2 positive electrode is used,
`
`and the load characteristics and the rernaining capacity after storage at 60 °C. for 7 days
`
`at 4.2 V are improved. However, Patent Document 2 doesnot refer to carboxylic acid in
`
`@ nonaqueous electrolyte solution when a specific acid anhydride is used, and does not
`
`suggest that there is a possibility that a cycle characteristic may be deteriorated by a
`
`carboxylic acid in & nonaqueous electrolyte solution and a specific effect wnen a specific
`
`acid anhydride and a carboxylic acid coexist in a certain amount is not suggested.
`
`{0005}
`
`in a Patent document 3, i has the anode and positive electrode, and nonaqueous
`alectolyie which may occlude and emit a lithium ion, The anode is a nonaqueous
`
`alectolie used for the nonaqueous electrolytic salution secondary battery containing the
`
`

`

`negative electrode active material which has at least 1 type of atoms chasen fram the
`
`group which consists of Si atom, an Sn atom, and a P b atom, A nonaqueoaus
`
`electrolytic solution contains at least one of a carbonate having at feast one of an
`
`unsaturated bond and a halogen atom and en acid anhydride having a specific structure.
`
`According to this, the conditions of the specific negative electrode, the carbonate having
`
`atleast one of an unsaturated bond and a halogen atom, and the acid anhydride having
`
`a specific structure are matched, so that the cycle characteristics are improved. However,
`
`Patent document 3 relates to carboxylic acid in a nonaqueous electrolyte salution.
`
`No description is given, and no suggestion is given of the possibility that the cycle
`
`characteristics deteriorate due to the carboxylic acid in the non-aqueous electrolyte
`solution and the specific effect when the specific acid anhydride and the carboxylic acid
`
`coexist at a certain content.
`
`iPrior art reference]
`
`iPatent document]
`
`{0006}
`
`{Patent document 1]JP 2001-057236A4
`
`[Patent document 2NJP 2004-307770A
`
`[Patent document 3JP 2007-20954 1A
`
`Summaryof the invention]
`
`iProblem to be solved by the invention]
`
`{0007}
`
`The present invention makes it problem to provide the nonacuieous electrolyte secondary
`
`cell using the nonaqueous electrolyte which improves a load charactenstic and a cycle
`
`characteristic, and this nonaqueous electrolyte in a nonaqueous electrolyte seconcary
`
`cell.
`
`iMeans for solving the preblern]
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`{0008}
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`AS a result of carrying oul various studies fo solve the above grablems, the present
`inventors have found that the above problems can be solved by Incorporating an acid
`
`anhydride of a specific structure fa compound of Formula 1)
`
`into a nonaqueous
`
`alectrolytic solution and controllinga carboxylic acid in a nonaqueous electrolytic solution,
`
`thereby completing the present invention.
`
`in other words, the present invention relates to a nonaqueous electrolytic solution used
`
`in a nonaqueous electrolytic solution secondary battery cornprising < (a) 4@ positive
`electrocie having a positive electrode active substance capable of storing and releasing
`
`a metal ion: and (2) a negative electrode having a negative electrode active material
`
`

`

`capable of absorbing and desorbing a metal ion.
`
`The composition contains a compound represented by general formula {1} and a4
`
`carboxylic acid,
`
`The nonaqueous electralyte solution is charactertzed in that the content of the carbaxylic
`
`acid is 0.00001 mass% or more and less than 0.01 mass% with respect to the total
`
`amount of the nonaqueous electrolyte solution.
`
`[O009)
`
`[Chemical formula 1}
`
`[OOO
`
`(in the formula, each of ihe symbols represents a hydrogen atom, a fluorine afom, an
`
`alkyl group, an alkenyl group, an group, or an aryl group.) R1,.R2,R3,R4,R5,R6
`
`(b) The nonaqueous electrolytic solution according to (a), wherein the content of the
`
`carboxylic acid is 0.00071% by rnass or more and less than 0.01% by mass based on the
`
`total amount of the nonaqueous electrolytic solution.
`
`{c) The nonaqueous electrolyte according to (a) or (b), wherein the carboxylic acid is
`
`represented by the following general formula (2) :.
`
`(004 4}
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`{Chemical formula 2]
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`{0042}
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`{(R 1, R 2, and R 3 each independently represents a hydrogen atom, a fluorine atom, an
`
`alkyl group, an alkeny! group, an alkynyl group, or an aryl group.
`
`{(d} A nonaqueous electrolyte according to any one of (a) fo (c), wherein the compound
`
`represented by formula (1)
`
`is a compound selected from the following group of
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`compounds (compounds A to D}:
`ee
`
`£0013}
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`[Chemical formula 3}
`
`

`

`[O01
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`() a cyclic carbonate having a carbon-carbon unsaturated bond, a cyclic carbonate
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`having a halogen atom, and The nonaqueous electrolytic solution according to any one
`
`of {a} to {d)}, which contains at least one selected from the graup consisting of nitriles,
`
`isocyanates, cycichexyibenzene, t-amylbenzene, t-butylbenzene, and sulfonic ester.
`
`(f) A nonaqueous electrolytic solution according fo any one of (a} to (}, which contains at
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`least one of nitriles or isocyanates.
`
`(a) A nonaqueous electrolyte secondary battery comprising a positive electrode having
`
`@ positive electrode active substance capable of storing and releasing a meta! ion anda
`
`negative electrode having a negative electrode active material capable of storing and
`releasing a metal ion; and 2
`
`{a} Or the nonaqueous electrolytic solution secondary battery using the nenaquecus
`
`elactolyte of any one description of the (f).
`
`fEffect of the Invention]
`
`[O075}
`
`According to the present invention, the nonaqueous electrolyte secondary cell axcellent
`
`in a load characteristic, a cycle characteristic, etc. can be obtained,
`
`{Mode for carrying out the invention]
`
`[O04]
`
`Hereinafter, embodiments of the present invention wil be described in detail. However,
`
`the following description is an example of an embadiment of the present invention
`
`{representative example), and the present invention is not limited fo these contents
`
`unless the scope of the appended claims is exceeded.
`
`{1. Nonaqueous Electrolyte solution}
`
`The nonaqueous electrolytic solution of the present invention contains an electrolyte and
`
`a nonaqueous solvent dissolving the electrolyte as in a general nonaqueous electrolytic
`
`solution.
`
`The compound denoted by a following general formula (1) and carboxylic acid are
`
`contained, and it is * of the aforementioned carboxylic acid.
`
`The arnount is 0.00001 mass%or more and less than 0.01 mass%s based on the total
`
`amount of the nonaqueous electrolyte.
`
`(0017)
`
`[Chemical formula 4]
`
`

`

`{O078)
`
`(ALR RARARS.RG is a hydrogen ator, a fluorine atom, and Al
`
`independcenily,
`
`respectively}
`
`A Kil group, an alkenyl group, an alkynyl! group, and an ary! group are expressed. }
`
`{1-1. A compound of formula (1}]
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`R1R2,.R3,.R4,.R5,R6 in (1) type of the description to Claim 1 expresses a hydrogen atom,
`
`@ fluorine afom, an alkyl group, an alkenyl group, an alkynyl group, and an aryl group
`
`independently, respectively. In addition, when the R1,R2,R3,R4,R5,R6 is an alkyl group,
`
`an alkenyl group, an alkynyl group or an aryl group, some or all of the hydragen atoms
`contained in these groups may be substituted with fluorine atoms.
`
`[OOTgI
`
`As an example of the above and an alkyl group, they are a methyl group, an ethyl group,
`
`and a n-propylgroup, Examples thereof inchicle an isopropyl group, a n-buly! group, a
`
`s-butyl group, a t-butyl group, an amyl group, a tamyl group, and a 2-ethyihexy! ester
`
`group.
`
`Specific examples of the alkenyl group include a viny! group, an ally! group, and a 2-
`
`butenyl group.
`
`[O020}
`
`Specific examples of the alkynyl group include an ethyny! group and a praparoy! group.
`
`As an example of the above and an aryl group, they are a phenyl group, a 2-tolyigroup,
`
`@ 3-tolyigroup, and a 4-tolyigroup, Exampiss thereof include a 2-t-butyiphenyl group, a
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`3-t-butohenyl group, a 4-t-butwiohenyl group, 4 2-lamylphenyl phosphate group, a 3-t-
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`amylphenyl phosphate group, and a 44-amyipheny! phosphate group.
`Specific examples of the compound of formula (1) include the following compounds.
`
`{0027}
`
`[Chemical formula 5]
`
`{0022}
`
`Among these compounds,itis preferable to use the following compounds.
`
`(0023)
`
`[Chemical formula 6]
`
`

`

`(9024)
`
`Since these compounds are relatively easy to manufacture and Nave moderate reactivity,
`
`the effect of improving battery characteristics is also large.
`
`The nonaqueous electrolytic solution of the present invention is characterized in that it
`
`contains a compound of Formula ¢1}, but the compound (1) is not limited to 1 types and
`
`may be used in combination.
`
`In addition, as the corfent of compound (7).
`
`(@ total amount when @ plurality of
`
`compoundsare used} is particularly limited.
`
`However, itis preferably 0.01% by mass or more, more preferably 0.1% by mass or more,
`
`sill more preferably 0.2% by mass or more, and preferably 10% by mass or jess, more
`
`oreferably 8% by mass or jess, stil more preferably 5% by mass or fess, based on the
`
`total amount of the nonaqueous electralyte sohition. When dt is within the above range,
`
`not only a stable fiim can be formed but also an increase in resistance can be suppressed,
`
`so that itis expected that the battery characteristics can be particularly improved.
`
`{025}
`
`[4-2. Carboxylic acid}
`
`The carboxylic acid Raving a content of jess than 0.01% by mass in the nonaqueous
`
`electrolytic solution of claim 7 is not particularly limited, but is preferably represented by
`
`the following general formula (2).
`
`(O026}
`
`{Chemical formula 7]
`
`{0027}
`
`{(R.1,R.2. and R 3 each independently represants a hydrogen atom, a fluorine alom, an
`
`alkyi group, an alkenyl group, an alkynyl group, or an aryl group.
`
`In addition, R14, R 2 and R 3 in Formula (2) preferably represent the same groups as R
`
`4,R 2 and R 3 in formula (4).
`
`AS a Specific compound of the above-mentioned carboxylic acid, the following are
`
`mentioned, for example.
`
`Acetic acid, propionic acid, butyric acid,
`
`isobutywic acid, benzoic acid, acrylic acid,
`
`methacrylic acid, crotanic acid, angelic acl, cinnamic acid, oxalic acid, malonic acid,
`
`succinic acid.
`
`

`

`[O028}
`
`When a carboxylic acid is contained in the nonaqueaus electrolyte solution, acrylic acid,
`
`methacrylic acid, crotonic acid, angelic acid, and cinnmarmic acid are preferred among the
`
`above. These carboxylic acids may be included in the compound of the oresent invention
`
`(1) or the hydrolysate as a hydrolysate, and are not necessary to be added separately to
`
`the nonaqueous electrolyte, and thus the acverse effect on the battery characteristics is
`
`small,
`
`When carboxylic acid is contained in the nonaqueous electrolyte solution of the. present
`invention, 1 kinds of carboxylic acids are nof limited, and a plurality of kinds may be used
`
`in combination. Also, the content of the carboxylic acid is determined based on the total
`amount of the nonaqueous electrolyte solution.
`
`In the case where the number(s) is (are combined), the total arnountis from O.00001%
`
`by mass to Jess than 0.01% by mass, preferably from 6.0007% by mass or more, more
`
`treferably from 0.0005% by mass or more, and preferably fram 0.0090% by mass or
`
`less, more preferably from 0.008% by mass or less, as the lower limit. When it is within
`
`the above range, it is expected that the battery characteristics are particularly improved
`
`without impairing the effect of the compound of Farmula (1). Further, in the case where
`
`the total amount of the nonaqueous electroiyte solution does not inchide the carboxylic
`
`acid (including 8 case in which the detection limit or the Hike is extrernely small), there is
`
`no possibility that a certain amount of carboxylic acid to be madified is not present. Since
`
`modification of the film is not sufficiently performed, it is important to keep the film to a
`
`certain extent because it contributes to improvement of battery characteristics.
`
`{9029}
`
`{1-3. electrolyte}
`
`There is no restriction in the electrolyte used for the nonaqueaus electolyte of the present
`
`invention, and if used for the target nonaqueous electrolyte secondary cell as an
`
`electrolyte, a publicly known thing is arbitranly employable.
`
`In using the nonaqueous
`
`electolyte of the present invention for a lithium secondary battery, it usually uses ithium
`
`salt as an electrolyte.
`
`{0030}
`
`As
`
`an
`
`electrolytic
`
`example,
`
`it
`
`is
`
`inorganic
`
`[ithium
`
`sai,
`
`such
`
`as
`
`LICIO4,LIASF6 LIPFS LIBF4, LISDFS LISOSFLIN(FSOS)2;
`LICF3SO3,LIN (FSO 2) (CF 3 SO 2), LIN (CF 3 SO 2) 2, LIN (C 2 F 5 SO 2) 2, lithium
`
`cyclic 4,3 = tteeeeneees
`
`Niniimice, lithium cycle 1,2 - tetraflucrcethanedisulfonamide, LIN (CF 3.50 2) (C4 F 9
`
`

`

`SO 2), LIC (CF 3 SO 2) 3, LIPF 4 (CF 3) 2, LIPF 4 (C 2 F 5) 2, LIPF 4 (CF 3 SO 2) 2,
`
`LIPF 4 (C2 F S30 2) 2, LIBF 2 (CF 3) 2, LIBF 2 (C 2 F 5) 2, LIBF 2 (CF 3 SO 2} 2, LIBH
`
`2(C 2F 5 SO 2} 2, and thelike.
`
`Examples thereof include a dicarboxylic acid complex Ithium salt such as ithium bis
`
`(oxalato} borate, lthium diflucrcoxalatoborate, Hihium tis (oxalate) phosohate, lithium
`
`difiuorobis (oxalato) phosphate, and *****""*"" (oxalatco} phosphate.
`
`{0034}
`Of these, LIPF6,LIBF4,LISOSF LIN (FSO 2) 2, LIN (FSO 2) (CE 3 SO.2), LIN (CF 3 S0
`2) 2, LIN(G 2 F 5 SO 2} 2,lithium bis (oxalato} borate, and LIN (C 2 F.5 SO) are obtained
`
`from the viewpoint of solubility and dissociation degree in a nonaqueous solvent and
`electric conductivdy. Preference is given fo lithium difluorcoxalaioborate,
`lithaim tris
`
`{oxalato} phosphate,
`
`fithium difluorchis foxalate) ohasphate,
`
`“““***"""""
`
`(oxalate)
`
`ohosphate, especially LIPF6,LIBF4.
`
`[0032]
`
`In addition, 7 kinds of electrolytes may be used alone, ar 2-or more kinds of electrolytes
`
`may be used in combination in any combination and ratio. Arnong these,it is preferable
`
`to use a combination of 2 kinds of specific inorganic lithium salts or a combination of an
`
`inorganic lithium sali and a flucrine-coniaining organic lithium salt, because gas
`
`generation during tickle charging is suppressed and deterioration after storage at high
`
`temperature is suppressed.
`
`in particular,
`
`it
`
`is preferable to use in combination a
`
`combination of LIPF 6 and LIBF 4, an inorganic lithium salt such as LIPF6,LIBF4. and a
`fluorine-containing organic ithium salt such as LICF3S03,LIN (CF 3 SO 23 2 and LIN (C
`
`2F 5 SO 2) 2.
`
`{0033}
`
`When using LIPF6 and LiBF4 together, it is preferable that LIBF4 is usually contained to
`
`the whole electrolyte by the ratio more than the 0.01 mass % and belowthe 50 mass %.
`
`The ratio is preferably 0.05% by mass or more, more preferably 0.15 by mass or more,
`
`and is preferably 20% by massor less, more preferably 10% by mass or less, particularly
`
`oreferably 6%by mass or fess.
`
`It is most preferably 3%by weight or Jess. When the ratie is within the above range, it is
`
`easy to obtain a desired effect, and by the law dissaciation deqree of LIBF 4,
`
`it is
`
`suppressed to increase the resistance of the electrolytic solution.
`
`{0034}
`
`On the other hand, inorganic lithium salt, such as LIPFS,LIBF4, inorganic lithium sail,
`such as LISOSF,LIN(FSO2Z) 2, and LCF3503 LN(CF3SO2) 2, LINC(C2FSSO02)2, lithium
`
`ringlike
`
`+,3-hexafluoropropanedisulfonyimide,
`
`Lithium
`
` ocydie
`
`a2
`
`-
`
`

`

`tetrafluoraethanedisulfonylimide, LIN (CF 3 SO 2) (C 4 F 9 SO 2), LiC (OF 3 SO 2) 3,
`
`LIPF 4 (CF 3) 2, @ fluorine-containing organic lithium salt such as LIPF 4 (C 2 F 5} 2,
`
`LIPF 4 (CF 3 SO 2) 2. PF 4(C 2F 5 SO 2) 2, LIBF 2 (CF 3) 2, LIBF 2(C 2 F 5) 2, LIBF
`
`2 (CF 3 SO 2) 2, and UB 2 (C 2 F 5 SO 2) 2 ;: Lithkun bis (oxalate) borate, thium tris
`
`{oxalate} phosphate When “ dicarboxylic acid complex lithium salt, such as lithium
`
`difiuoro
`
`oxalate
`
`borate,
`
`fithium
`
`bird
`
`{oxalate}
`
`phosphate,
`
`ithium
`
`difuorobis(oxalato}phosphate, and lithium tetrafluaro (oxalate) phosphate, etc. are used
`
`together, The proportion of inorganic lithium salt occupying the entire electrolyie is
`
`usually 70% by mass or more, preferably 60% by mass or more, and more preferably
`
`85% by mass or more.
`Further, it is usually 99% by mass orless, anc preferably 95% by mass or less.
`
`[OOS]
`
`The concentration of the lithium salt in the nonaqueous electrolytic solution of the present
`
`mventon does not imparthe gist of the present invention.
`
`It is optionally 0.4 mol/L or more, preferably 6.6 mol/L or rnore, and more preferably
`
`0.8 mol/L or more. Further, it is usually A mol/L or less, preferably 2 mol/L or less,
`
`more preferably 1.6 mol/L or less, and stil more preferably 1.6 mol/L or less. When
`
`the concentration of the Hthiurn salt is within the above range, the electrical canductivity
`
`af the nonaqueous electrolytic solution becomes sufficient, and the electrical conductivity
`
`due ta the increase in viscosity decreases, and the performance of the nonaqueous
`
`electrolytic solution secondary battery using the nonaqueous electralytic solution of the
`
`present invention decreases in performance performance of the nonaqueous electrolytic
`
`solution 2.
`
`{0036}
`
`1-4. nonaqueous solvent]
`AS @ nonaqueous solvent contained in the nonaqueous slectrolytic salution of the present
`
`invention, a nonaqueous electralyte solution which is conventionally known asa solvent
`
`of 2 nonaqueous electrolytic solution can be used.
`
`Examples of commonly used nonaqueous solvents include cyclic carbonates,
`
`linear
`
`carbonates,
`
`linear and cyclic carboxylic esters,
`
`linear and cyclic Ether, phosphorus-
`
`containing organic solvents, sulfur-containing organic solvents, aromatic fluorine-
`
`containing solvents, and the like.
`
`[O037)
`
`The cyclic carbonate includes a cyclic carbonate such as ethylene carbonate, propylene
`
`carbonate, and butylene carbonate, and the number of carbon atoms of the cyclic
`
`

`

`carbonate is usually 3 te 8. When it is easy to dissolve an electrolyte also in these since
`
`ethylene carbonate and propylene carbonate have the high dielectric constant, and it is
`
`made a nonaqueous electrolytic solution secondary battery, a cycle characteristic is
`
`mreferable at the paint that it
`
`is good. Further, cyclic carbonates in which a part of
`
`hydrogen of these compounds is substituted with fluorine may be mentioned. As the
`
`cychc carbonate substituted with fluorine, fluoroethylene carbonate, 1,2-difluoroethylene
`
`ester carbonate, 1,1-difluoroethylene ester carbonate, 1,1,2-trifluoroethwiene carbonate,
`
`tetrafluoroethylene carbonate, and tetraflucrosthylene carbonate are used. Examples
`
`thereof include a cyclic carbonate substituted with fluorine such as a 1-fuoro-2-
`
`methylethylene ester carbonate, a i-fluore-i-methylethylene ester carbonate, a 1,2-
`difluoro-t-methylethylene ester carbonate, a 1,1,2-triflucra-2-methylethyiene ester
`
`carbonate, and a trifluoro methyl ethylene carbonate, and a cyclic carbonate having 3 to
`
`& carbon atorns. Of
`
`these,
`
`fluoroethylene carbonate, 1,2-difluoroethylene ester
`
`carbonate and trifluora methyl ethylene carbonate are preferred.
`
`[0038]
`
`As chain carbonate, they are dimethyl carbonate, ethyl methyl carbonate, and *.
`
`A chain carbonate such as *******" methyl-n-propy! carbonate, ethyl-n-prapyl carbonate,
`
`or di-n-propyl carbonate is included, and the number of carbon atams of the constituting
`
`alkyl group is preferably 1 to 5, and particularly preferably 1 to 4. Especially, dimethyl
`
`carbonate, diethyl carbonate, and ethy! methyl carbonate are preferable from a point of
`
`the improvernent in a battery characteristic. Further, a chain carbonate in which 4 part of
`
`hydrogen of an alkyl group is substituted with fluorine is also included. As a chain
`
`carbonate substituted with fluorine, bis (lucromethyl) carbonate, bis (diflucromethyl)
`
`carbonate, and bis (dfluoromethyl) carbonate are used. Examples include bis (tri
`
`flUcromeihy)
`
`carbonate,
`
`bis(Z-fluormethyl
`
`esterjcarbonate,
`
`bis(2,2-diflucraethy!
`
`asterjcarbonate, bis(2,2,2-trifluoroethy! esterjcarbonate, 2-fluoroethy! ester methyl
`
`carbonate, 2,2-acid cdifluoroethylmethy! ester carbonate, 2,2,2-trifluoroethy! ester methyl
`
`carbonate, and the like.
`
`10039}
`
`As a chain carboxylic ester, methyl acetate, ethyl acetate, propy! acetate,
`
`isopropy!
`
`acetate, butyl acetate, he xaacetate s ec-huty!, iso-buty! acetate, hexaacetate t-butyl,
`
`methyl propionate, ethyl propionate and ethyl propionate are used. Examples thereof
`
`include propyl propionate, isopropyl propionate, methyl butyrate, ethyl butyrate, propyl
`
`butyrate, methy! isobutyrate, ethyl isobutyrate, methyl valerate, ethyl valerate, methy!
`
`tivalate, ethyl pivalate, and the like, and lmear carboxylic acid esters m which a partion
`
`ef hydragen of these compounds is substituted with fluorine. As chain carboxylate
`
`

`

`replaced with
`
`fluoride,
`
`they are triluoromethy! acetate,
`
`tifluorcethyl acetate,
`
`triflucropropy! acetate, triflucrobutyl acetate, the trifluoroacetic acid 2 and 2, and 2-bird
`eee
`
`Examples thereof inciude ethyl and the fixe. Of these, methyl acetate, ethy! acetate.
`
`propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propy! propionate,
`
`methyl butyrate, ethyl butyrate, methyl valerate, methyl isobutyrate, ethyl isobutyrate,
`
`and methyl pivalate are preferred from the viewpoint of improving the battery
`characteristics.
`
`[0040}
`Examples of the cyclic carboxylic ester inclucle y-buiyrolactone, y-valeralactone and the
`
`like, and cyclic carboxylic esters in which a part of the hydrogens of these compoundsis
`
`replaced with fluorine. OF these, y-butyroiactone is more preferred.
`
`AS a chain Ether, dimethoxymethane, 1,1-dimethoxyethane, 1,2-dimethoaxyethane,
`
`diethoxymethane, 1,1-diethoxyethane, or the like is used.Mention may be made of 1,2-
`
`diethoxyethane,
`
` ethoxymethoxymethane,
`
`j,1-ethoxymethexy
`
` ethancic,
`
`1,2-
`
`ethoxymethoxy ethanocic, and the like, and linear Ether in which a portion of the
`
`hydrogens of these compounds have been replaced with fluorine. As 4 chain-like Ether
`
`substituted with fluorine, bis Grifluoroethoxy) ethane, <P°esssseeteeee | a eseestaoowesenes
`
`4.4,1,2.2,3,4,5,5,5 - decafluorg-3-methoxy-4-influoromethyl-pentanoic, ar the tke is used.
`
`Examples thereof include a 1,1.1,2.2,3,4,5,5,5 decafluoro-3-ethoxy-4-tiflucromethyl-
`
`pentanoic, a 1,1,1,2,2,3,4,5,5,5 decafhuora-3-propoxy-4+-inifluoromethyl-pentanoic, a
`
`1.1,2,2-tetrafiuoroethy-2,2,3,3-tetrafluoropropy! ether, and a 2,2-difluoroethyl ester-
`
`2,2,4,0-tetrafluoropropyl ether. Of these, 1,2-dimethoxyethane and 1,2-diethoxyethane
`
`are more preferred,
`
`{0044}
`Examples of the cyalic Ether include tetrahydro furan, ?-methylietrahydrofuran and the
`
`like, and cyclic Ether in which a part of the hydrogens of these carmpounds is substituled
`with fluaring.
`
`As the phosphorus-containing organic solvent, irimethy phosphate, tnethy! phosphate,
`
`dimethyl athy! phosphate, methyl diethyl phosphate, ethylene methy phosphate, *’*****
`
`phosphate,
`
`tripheny! phosphate,
`
`trimethy! phosphite,
`
`triethyl phosphite,
`
`tripheny!
`
`phosphite and the like are used. Mention may be made of timethylphosphine oxide, tn
`
`ethyiphosphine oxide, trishenylphesphine oxide and the like, and phosphorus-cantaining
`
`organic solvents in which some of the hydrogens of these campouncds have been
`
`replaced by fluarine. Phaspharic acid tris (2.2.2 - *****"*") as a phosphorus-containing
`
`

`

`organic solvent substituted with fluorine
`
`Exampies thereof include a tris phosphate(2, 2.3,3,3-pentafluorapropyl ester) and the dke.
`
`{0042}
`
`As the sulfur-containing arganic solvent, sulfolane, 2-methylsulfolane, 3-methyisulfolane,
`
`dimethyisulfone,
`
`diethyisulfone,
`
`ethyimethy!
`
`sulfone,
`
`methylipropyl
`
`sulfone,
`
`dimethylsulfoxide,
`
`and the
`
`like
`
`are used. Examples
`
`thereof
`
`include methyl
`
`methanesulionate, ethyl methanesulfonaie, methyl ethanesulfonate, ees. dimethy!
`
`sulfate, diethyl sulfate, dibuty! sulfate, arid the ike, and sulfur-containing organic solvents
`
`in which a portion of the hydrogens of these compounds have been replaced with fluorine.
`
`(0043)
`Examples
`
`of
`
`the
`
`aromatic
`
`fluorine-containing
`
`salvent
`
`include Hucrobenzene,
`
`difuorobenzene,
`
`trifluorobenzene,
`
`tetrafluorabenzans,
`
`pentafluarobenzene,
`
`hexafluorobenzene, and benzotri fluoride.
`
`Among the above nonaqueous solvents, if is preferable fo use ethylene carbonate and /
`
`or propylene carbonate which is a cyclic carbonate, and further, it is preferable to use a
`
`combination of these and a chain carbonate from the viewpoint of achieving both high
`
`conductivity and low viscosity of an electralytic solution,
`
`{044}
`
`+ kinds of non-aqueous solvents may be usad alone, or 2 or more kinds may be used in
`
`combination in any combination and rate. When 2 or more of them are used in
`
`combination, for example, when a cyclic carbonate and a linear carbonate are used in
`
`combination, a preferable content of a chain carbonate in a nonaqueous salvent is
`
`usually 20%by volume or more, preferably 40% by volume or more, and usually 95% by
`
`volume or less, preferably 90%by volume or less.
`
`It comes out. On the other hand, a preferable content of the cyclic carbonate in the
`
`