(19)
(11)EP 1 715 542 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
10.09.2008 Bulletin 2008/37

(21)Application number: 06112896.3

(22)Date of filing:  21.04.2006
(51)International Patent Classification (IPC): 
H01M 10/40(2006.01)
H01M 6/22(2006.01)

(54)

Polymer electrolyte for a lithium secondary battery

Polymerelektrolyt für sekundäre Lithiumbatterien

Électrolyte polymère pour une batterie secondaire au lithium


(84)Designated Contracting States:
DE FI FR GB

(30)Priority: 21.04.2005 KR 2005033084

(43)Date of publication of application:
25.10.2006 Bulletin 2006/43

(73)Proprietor: Samsung SDI Co., Ltd.
Suwon-si Gyeonggi-do (KR)

(72)Inventors:
  • Lee, Yong-Beom
    Gongsae-dong, Kiheung-gu, Yongin-si, Kyunggi-do (KR)
  • Cheong, Kwang-Jo
    Gongsae-dong,Kiheung-gu Yongin-si, Kyunggi-do (KR)
  • Song, Eui-Hwan
    Gongsae-dong,Kiheung-gu Yongin-si, Kyunggi-do (KR)

(74)Representative: Hengelhaupt, Jürgen et al
Gulde Hengelhaupt Ziebig & Schneider Wallstrasse 58/59
10179 Berlin
10179 Berlin (DE)


(56)References cited: : 
EP-A- 1 347 462
EP-A- 1 524 709
EP-A- 1 508 934
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    FIELD OF THE INVENTION



    [0001] The present invention relates to a polymer electrolyte for lithium secondary batteries, a lithium secondary battery comprising same and a monomer for polymerization of the polymer electrolyte. The lithium secondary battery having an inventive electrolyte endures external physical impact and maintains mechanical strength after storage at high temperature.

    BACKGROUND OF THE INVENTION



    [0002] Recently, reductions in the size and weight of portable electronic equipment have led to the development of batteries for use in such equipment. Batteries having high energy density are used as the power sources for this portable equipment, and lithium secondary batteries have been actively researched.

    [0003] In a lithium secondary battery cell, lithium-transition metal oxides are used as the positive active material and crystalline or amorphous carbon or carbon complexes are used as the negative active material. Positive and negative electrodes are formed by coating the appropriate active material slurry or applying the appropriate active material film onto current collectors to a desired thickness and length. An electrode assembly is fabricated by positioned an insulative separator between the positive and negative electrodes and spiral-winding or laminating the electrodes and the separator. The lithium secondary battery cell is fabricated by inserting the electrode assembly into a battery case, such as a metal can or metal laminated pouch, and injecting an electrolyte solution in the battery case.

    [0004] Battery pouches afford the batteries shape freedom and increased battery capacity relative to cans. However, pouches are easily modified and damaged by external physical impact and swell during storage at high temperature. These problems are more serious in lithium secondary batteries using liquid electrolyte solutions than they are in lithium secondary batteries using polymer electrolyte solutions. Therefore, batteries using pouches generally use polymer electrolyte solutions.

    [0005] Polymer electrolyte lithium secondary batteries have advantages such as leak prevention, safety, high temperature stability, durability against external physical impact and the like. Much research has been conducted into improving the stability of such batteries against external physical impact and reducing the deterioration of physical strength during high temperature storage.

    SUMMARY OF THE INVENTION



    [0006] According to a first aspect of the invention there is provided a polymer electrolyte for a lithium secondary battery comprising:

    a non-aqueous organic solvent;

    a lithium salt; and

    a polymer according to independent claim 1.



    [0007] Preferably, the at least one alcohol is selected from the group consisting of polyethylene glycol, polypropylene glycol, alkanediol, ethoxylated alkanediol, propoxylated alkanediol, trimethylolpropane, ethoxylated trimethylolpropane, propoxylated trimethylolpropane, ditrimethylolpropane, ethoxylated ditrimethylolpropane, propoxylated ditrimethylolpropane, pentaerythritol, ethoxylated pentaerythritol, propoxylated pentaerythritol, dipentaerythritol, ethoxylated dipentaerythritol, propoxylated dipentaerythritol, bisphenol A, ethoxylated bisphenol A, propoxylated bisphenol A.

    [0008] Preferably, each of A and B is selected from the group consisting of (meth)acryl groups, vinyl groups, allyl groups, vinylsulfonyl groups, urethane(meth)acryl groups, and combinations thereof.

    [0009] Preferably, the lithium salt is selected from the group consisting of LiPF6, LiBF4, lithium bis(oxalato) borate, LiSbF6, LiAsF6, LiClO4, LiCF3SO3, LiN(CF3SO2)2, LiN(C2F5SO2)2, LiAlO4, LiAlCl4, LiN(CxF2x+1SO2)(CyF2y+1SO2) wherein x and y are natural numbers, LiSO3CF3, and combinations thereof.

    [0010] Preferably, the non-aqueous organic solvent is selected from the group consisting of carbonates, esters, ethers, ketones, nitriles, and combinations thereof. Alternatively, the non-aqueous organic solvent may comprise a carbonate-based solvent and an aromatic hydrocarbon-based organic solvent. Preferably, the aromatic hydrocarbon-based organic solvent is an aromatic compound represented by Formula 9:

    wherein R2 is selected from the group consisting of halogens, C1 to C10 alkyls and combinations thereof, and q is an integer ranging from 0 to 6. More preferably, the aromatic hydrocarbon-based organic solvent is selected from the group consisting of benzene, fluorobenzene, toluene, fluorotoluene, trifluorotoluene, xylene, and combinations thereof.

    [0011] Preferably, the polymer electrolyte further comprises a carbonate additive selected from the group consisting of vinylene carbonate, divinylsulfone, ethylene sulfite, carbonates having substituents selected from the group consisting of halogens, cyano (CN) groups, nitro (NO2) groups and combinations thereof. More preferred, the carbonate additive is selected from the group consisting of carbonates having substituents selected from the group consisting of halogens, cyano (CN) groups and nitro (NO2) groups. The carbonate additive is preferably selected from the group consisting of compounds represented by Formula 10:

    wherein X1 is selected from the group consisting of halogens, cyano (CN) groups and nitro (NO2) groups. Preferably, the carbonate additive is fluoroethylene carbonate.

    [0012] According to a second aspect of the invention there is provided a lithium secondary battery comprising:

    a positive electrode comprising a positive active material capable of intercalating and deintercalating lithium ions;

    a negative electrode including a negative active material capable of intercalating and deintercalating lithium ions; and

    the inventive polymer electrolyte as described above.



    [0013] The polymer electrolyte may have a shear strength relative to the positive electrode of about 0.7N/mm or greater. Preferably, the shear strength relative to the positive electrode is ranging from about 0.7N/mm to about 1.5N/mm, more preferably ranging from about 1.0N/mm to about 1.5N/mm, most preferably ranging from about 1.2N/mm to about 1.5N/mm.

    [0014] The polymer electrolyte may have a shear strength relative to the positive electrode of about 0.7N/mm or greater and a peel strength relative to the positive electrode of about 0.002N/mm or greater. Preferably, the shear strength relative to the positive electrode is ranging from about 0.7N/mm to about 1.5N/mm and the polymer electrolyte has a peel strength relative to the positive electrode ranging from about 0.002 to about 0.07N/mm. More preferred, the shear strength relative to the positive electrode is ranging from about 1.0N/mm to about 1.5N/mm and the polymer electrolyte has a peel strength relative to the positive electrode ranging from about 0.015 to 0.07N/mm. Most preferred, the shear strength relative to the positive electrode is ranging from about 1.2N/mm to about 1.5N/mm and the polymer electrolyte has a peel strength relative to the positive electrode ranging from about 0.035 to 0.07N/mm.

    [0015] Preferably, the negative active material is a carbon-based material.

    [0016] Preferably, the positive active material is a lithiated intercalation compound.

    [0017] According to a third aspect of the invention there is provided a monomer for a polymer electrolyte represented by Formula 1:

             A-polyesterpolyol-B     (1)

    wherein the polyesterpolyol is being obtained by condensation of at least one alcohol having from 2 to 6 OH groups, the polyesterpolyol is having a weight average molecular weight ranging from about 100 to about 10,000,000, and each of A and B are linked to terminal OH groups of the polyesterpolyol, each of A and B being selected from the group consisting of CH2=CR-C(=O)-, CH2=CR-O-CH2-, CH2=CR-, CH2=CR-O-C(=O)-, CH2=CH-CH2-O-, CH2=CH-S(=O)2-, and CH2=CR-C(=O)-O-CH2CH2-NH-C(=O)-, wherein R is selected from the group consisting of C1 to C10 hydrocarbons and C6 to C10 aromatic hydrocarbons.

    [0018] According to the invention, the lithium secondary battery includes the inventive polymer electrolyte which is durable against external physical impact and which maintains physical strength during high temperature storage. The lithium secondary battery includes a positive electrode having a positive electrode active material capable of intercalating and deintercalating lithium ions, a negative electrode having a negative electrode active material capable of intercalating and deintercalating lithium ions, and a polymer electrolyte comprising a polymer, a non-aqueous organic solvent, and a lithium salt. The polymer electrolyte has a shear strength relative to the positive electrode of about 0.7N/mm or greater. Further, the polymer electrolyte has a peel strength relative to the positive electrode of about 0.002N/mm or greater.

    BRIEF DESCRIPTION OF THE DRAWING



    [0019] The above and other features and advantages of the present invention will become more apparent by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:

    FIG. 1 is a schematic perspective view of a lithium secondary battery according to one embodiment of the present invention.


    DETAILED DESCRIPTION OF THE INVENTION



    [0020] In one embodiment of the present invention, a lithium secondary battery includes a metal laminated pouch as the battery case. The pouch affords the battery shape freedom and increased battery capacity relative to a metal can, but has less mechanical strength than the can. The lithium secondary battery includes a polymer electrolyte that preserves battery performance, prevents leaking, and improves mechanical properties, safety, and storage characteristics at high temperature.

    [0021] The lithium secondary battery includes a positive electrode having a positive active material capable of intercalating and deintercalating lithium ions, a negative electrode having a negative active material capable of intercalating and deintercalating lithium ions, and a polymer electrolyte. The polymer electrolyte may have a shear strength relative to the positive electrode of about 0.7N/mm or greater, preferred ranging from about 0.7 to about 1.5N/mm, more preferred ranging from about 1.0 to about 1.5N/mm, most preferred ranging from about 1.2 to about 1.5N/mm.

    [0022] According to the present invention, the polymer electrolyte may have a shear strength relative to the positive electrode of about 0.7N/mm or greater and a peel strength relative to the positive electrode of about 0.002N/mm or greater. In another embodiment, the polymer electrolyte has a shear strength relative to the positive electrode ranging from about 0.7 to about 1.5N/mm and a peel strength relative to the positive electrode of about 0.006 to about 0.07N/mm. In yet another embodiment, the polymer electrolyte has a shear strength relative to the positive electrode ranging from about 1.0 to about 1.5N/mm and a peel strength relative to the positive electrode of about 0.015 to about 0.07N/mm. In still another embodiment, the polymer electrolyte has a shear strength relative to the positive electrode ranging from about 1.2 to about 1.5N/mm and a peel strength relative to the positive electrode ranging from about 0.035 to about 0.07N/mm.

    [0023] When the shear strength is less than about 0.7N/mm, or when the shear strength and peel strength are outside the above-described ranges, the mechanical strength of the battery and battery performance are deteriorated.

    [0024] The shear strength and peel strength of the electrolyte depend on the polymer used in the electrolyte. According to the present invention, the polymer electrolyte includes a polymer obtained by polymerization of a first monomer represented by the following Formula 1:

             A-polyesterpolyol-B     (1)



    [0025] In Formula 1, the polyesterpolyol is produced by a condensation reaction of at least one alcohol having 2 to 6 OH groups and at least one dicarboxylic acid. The polyesterpolyol has a weight average molecular weight ranging from about 100 to about 10,000,000. A and B are linked to the terminal OH groups of the polyesterpolyol and can be the same or different. A and B are each selected from the group consisting of CH2=CR-C(=O)-, CH2=CR-O-CH2-, CH2=CR-, CH2=CR-O-C(=O)-, CH2=CH-CH2-O-, CH2=CH-S(=O)2-, or CH2=CR-C(=O)-O-CH2CH2-NH-C(=O)-, where R is a C1 to C10 hydrocarbon or a C6 to C10 aromatic hydrocarbon.

    [0026] The polymer electrolyte is being obtained by polymerization of the first monomer represented by Formula (1) and a second monomer represented by one of Formulas 2 through 7:

             CH2=CR1-C(=O)-O-X     (2)

             CH2=CR1-O-X     (3)

             CH2=CR1-O-C(=O)-X     (4)

             CH2=CH-CH2-O-X     (5)

             CH2=CH-S(=O)2-X     (6)

             CH2=CR1-C(=O)-O-CH2CH2-NH-C(=O)-O-X     (7)



    [0027] In Formulas 2 through 7, R1 is selected from the group consisting of H, C1 to C10 hydrocarbons and C6 to C10 aromatic hydrocarbons, and X is selected from the group consisting of C1 to C20 hydrocarbons, C1 to C20 halogenated hydrocarbons, C6 to C20 aromatic hydrocarbons and C6 to C20 halogenated aromatic hydrocarbons. Preferably, the second monomer is selected from the group consisting of compounds represented by Formulas 3, 6 and 7.

    [0028] Compounds represented by Formula 1 include polyethylene glycol, polypropylene glycol, alkanediol, ethoxylated alkanediol, propoxylated alkanediol, trimethylolpropane, ethoxylated trimethylolpropane, propoxylated trimethylolpropane, ditrimethylolpropane, ethoxylated ditrimethylolpropane, propoxylated ditrimethylolpropane, pentaerythritol, ethoxylated pentaerythritol, propoxylated pentaerythritol, dipentaerythritol, ethoxylated dipentaerythritol, propoxylated dipentaerythritol, bisphenol A, ethoxylated bisphenol A, and propoxylated bisphenol A.

    [0029] One example of polyesterpolyol is represented by the following Formula 8.



    [0030] In Formula 8, X, Y, and Z can be the same or different, and are repeating units which can be divalent (or higher valence) alkylene oxides, alkylene imines or repeating units thereof. X, Y and Z can also be an alkylene group. In the Formula, each of x, y, and z is an integer ranging from 1 to 20, and each of l, m, and n is 0 or 1 or greater and is controlled based on the molecular weight of the target polymer.

    [0031] In Formula 1, A and B can be the same or different and each is selected from the group consisting of (meth)acryl groups, vinyl groups, allyl groups, vinylsulfonyl groups, urethane(meth)acryl groups and combinations thereof. Preferably, each of A and B is selected from the group consisting of (meth)acryl groups, vinyl groups, vinylsulfonyl groups, urethane(meth)acryl groups and combinations thereof.

    [0032] In one preferred embodiment of the present invention, the polymer is present in the polymer electrolyte in an amount ranging from about 1 to about 30 wt%, more preferred ranging from about 3 to about 25 wt%. When the polymer is present in an amount less than about 1 wt%, battery strength deteriorates. When the polymer is present in an amount greater than about 30 wt%, battery performance deteriorates.

    [0033] When first and second monomers are used, they are preferably used in a weight ratio ranging from about 1:1 to about 1:60. More preferred, the weight ratio of the first and second monomers ranges from about 1:5 to about 1:40. When the weight ratio is outside these ranges, battery strength and performance deteriorate.

    [0034] To initiate polymerization of the monomers, a polymerization initiator is used. The polymerization initiator may be any material capable of easily initiating polymerization of the monomers and which does not deteriorate battery performance. Nonlimiting examples of suitable polymerization initiators include organic peroxides and azo-based compounds.

    [0035] Organic peroxides for use as the polymerization initiator can include peroxy dicarbonates, diacyl peroxides and peroxy esters. Nonlimiting examples of suitable peroxy esters include di(4-t-butylcyclohexyl) peroxydicarbonate, di-2-ethylhexyl peroxy dicarbonate, di-isopropyl peroxy dicarbonate, di-3-methoxy butyl peroxy dicarbonate, t-butyl peroxy isopropyl carbonate, t-butyl peroxy 2-ethylhexyl carbonate, 1,6-bis(t-butyl peroxycarbonyloxy)hexane, diethylene glycol-bis(t-butyl peroxy carbonate) and the like. Nonlimiting examples of suitable diacyl peroxides include diacetyl peroxide, dibenzoyl peroxide, dilauroyl peroxide, and bis-3,5,5-trimethyl hexanoyl peroxide. Nonlimiting examples of suitable peroxy esters include perhexyl pivalate, t-butyl peroxypivalate, t-amyl peroxypivalate, t-butyl peroxy-2-ethyl-hexanoate, t-hexylperoxy pivalate, t-butyl peroxy neodecanoate, t-butyl peroxy neoheptanoate, t-hexylperoxy pivalate, 1,1,3,3-tetra methyl butyl peroxy neodecanoate, 1,1,3,3-tetramethyl butyl peroxy 2-ethylhexanoate, t-amyl peroxy 2-ethyl hexanoate, t-butyl peroxy isobutyrate, t-amylperoxy 3,5,5-trimethyl hexanoate, t-butyl peroxy 3,5,5-trimethyl hexanoate, t-butyl peroxy acetate, t-butyl peroxy benzoate, di-butylperoxy trimethyl adipate, and the like.

    [0036] Nonlimiting examples of suitable azo-based compounds for use as the polymerization initiator include 2,2'-azo-bis(isobutyronitrile), 2,2'-azo-bis(2,4-dimethylvaleronitrile), and 1,1'-azo-bis(cyanocyclohexane).

    [0037] The polymerization initiator is used in an amount sufficient to initiate polymerization of the monomers. Preferably, the polymerization initiator is used in an amount ranging from about 0.01 to about 5 wt% based on the total weight of the monomers.

    [0038] The polymer electrolyte composition further includes a non-aqueous organic solvent and a lithium salt, both of which are generally provided in a liquid electrolyte solution. The lithium salt acts as a source of lithium ions in the battery, enabling the basic operation of the lithium battery. Examples of suitable lithium salts include LiPF6, LiBF4, lithium bis(oxalato) borate (LiBOB), LiSbF6, LiAsF6, LiClO4, LiCF3SO3, LiN(CF3SO2)2, LiN(C2F5SO2)2, LiAlO4, LiAlCl4, LiN(CxF2x+1SO2)(CyF2y+1SO2) (where, x and y are natural numbers), LiSO3CF3 and mixtures thereof.

    [0039] Preferably, the concentration of the lithium salt ranges from about 0.6 to about 2.0M, more preferred from about 0.7 to about 1.6M. When the concentration of the lithium salt is less than about 0.6M, electrolyte conductivity and performance decrease. When the concentration of the lithium salt is greater than about 2.0M, the viscosity of the electrolyte increases and the mobility of lithium ions decreases.

    [0040] Examples of suitable non-aqueous organic solvents include carbonates, esters, ethers, ketones, nitriles and mixtures thereof. The carbonates can include dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate, ethylene carbonate, propylene carbonate, butylene carbonate and the like. The esters can include methyl acetate, ethyl acetate, methyl hexanoate, methyl formate and the like. The ketones can include γ-butyrolactone, γ-valerolactone, γ-caprolactone, δ-valerolactone, ε-caprolactone and the like. The nitriles can include acetonitrile and the like.

    [0041] When a carbonate-based solvent is used as the non-aqueous organic solvent, a mixture of cyclic and linear carbonates can be used in a volume ratio ranging from about 1:1 to about 1:9. When cyclic and linear carbonates are used within this volume ratio range, electrolyte performance improves.

    [0042] The non-aqueous organic solvent can further include an aromatic hydrocarbon-based organic solvent. Preferably, the aromatic hydrocarbon-based organic solvent is represented by the following Formula 9.



    [0043] In Formula 9, R2 is selected from the group consisting of halogens, C1 to C10 alkyls and combinations thereof, and q is an integer ranging from 0 to 6.

    [0044] Examples of suitable aromatic hydrocarbon-based compounds include benzene, fluorobenzene, toluene, fluorotoluene, trifluorotoluene, and xylene.

    [0045] Preferably, the polymer electrolyte composition further includes an additive. The additive can be a carbonate additive having a substituent selected from the group consisting of halogens, cyano (CN) groups, nitro (NO2) groups, vinylene carbonate, divinylsulfone, and ethylene sulfite. The additive inhibits swelling at high temperatures, and improves electrochemical properties such as capacity, cycle-life, low temperature characteristics, and the like. The carbonate additive can comprise an ethylene carbonate derivative represented by the following Formula 10:



    [0046] In Formula 10, X1 is selected from the group consisting of halogens, cyano (CN) groups, and nitro (NO2) groups. Preferably, fluoroethylene carbonate is used as the additive.

    [0047] The carbonate additive is present in an amount ranging from about 0.01 to about 10 parts by weight based on 100 parts by weight of the polymer electrolyte composition. Preferably, the additive is present in an amount ranging from about 0.01 to about 5 parts by weight based on 100 parts by weight of the polymer electrolyte composition. When the carbonate additive is present in an amount less than about 0.01 parts by weight, inhibition of gas generation inside the battery is difficult. When the additive is present in an amount greater than about 10 parts by weight, the cycle-life of the battery at high temperature deteriorates and the battery swells at high temperature.

    [0048] A lithium secondary battery according to the present invention is fabricated by first forming an electrode assembly by winding a positive electrode, a negative electrode and a separator. The electrode assembly is inserted into a battery case, and the polymer electrolyte composition is injected into the case. After injecting the case with the electrolyte composition, the composition is cured. The process by which the composition is cured is well-known in the art. During curing, the polymerization of the monomers of the polymer electrolyte composition is initiated by a polymerization initiator. After curing, the resulting battery has a polymer-type electrolyte. The battery case may be a metal can or a metal-laminated pouch. However, the effects of the polymer electrolyte composition are improved when it is injected into a pouch type battery case.

    [0049] The positive electrode includes a positive active material capable of intercalating and deintercalating lithium ions. Such a positive active material can include lithiated intercalation compounds selected from the group consisting of compounds represented by the following Formulas 11 through 22.

             LixMn1-yMyC2     (11)

             LixMn1-yMyO2-zDz     (12)

             LixMn2O4-zDz     (13)

             LixCo1-yMyC2     (14)

             LixCo1-yMyO2-zDz     (15)

             LixNi1-yMyC2     (16)

             LixNi1-yMyO2-zCz     (17)

             LixNi1-yCoyO2-zDz     (18)

             LixNi1-y-zCoyMzCα     (19)

             LixNi1-y-zCoyMzO2-αDα     (20)

             LixNi1-y-zMnyMzCα     (21)

             LixNi1-y-zMnyMzO2-αDα     (22)



    [0050] In Formulas 11 through 22, 0.90 ≤ x ≤ 1.1, 0 ≤ y ≤ 0.5, 0 ≤ z ≤ 0.5, 0 ≤ α ≤ 2, M is selected from the group consisting of Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements and mixtures thereof, C is selected from the group consisting of O, F, S and P, and D is selected from the group consisting of F, S and P.

    [0051] The negative electrode includes a negative active material capable of intercalating and deintercalating lithium ions. Examples of suitable negative active materials include carbon-based negative active materials such as crystalline or amorphous carbon and carbon complexes.

    [0052] The positive and negative electrodes are fabricated by first preparing active material compositions by mixing the active material, a conductive agent, and a binder in a solvent to form a slurry. The slurry is then coated on a current collector as is well known in the art.

    [0053] The conductive agent may comprise any material which does not induce chemical modification and which is electrically conductive. Examples of suitable conductive agents include carbon black, acetylene black, ketjen black, carbon fibers, metal powders and metal fibers including metals such as copper, nickel, aluminum, silver, and the like.

    [0054] The binder may include any material capable of firmly attaching the active materials and conductive agents to the current collector. Examples of suitable binders include polyvinylalcohol, carboxylmethylcellulose, hydroxypropylenecellulose, diacetylenecellulose, polyvinylchloride, polyvinylpyrrolidone, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene and the like.

    [0055] The solvent can include any solvent capable of dispersing the active material, conductive agent and binder. One Example of the solvent is N-methylpyrrolidone.

    [0056] One embodiment of a non-aqueous electrolyte secondary battery according to the present invention is illustrated in FIG. 1. The battery is a pouch-type lithium ion battery 1 fabricated by inserting an electrode assembly 9 into a battery case 15. The electrode assembly 9 includes a negative electrode 3, a positive electrode 5, and a separator 7 positioned between the positive and negative electrodes. An electrolyte solution is injected into the battery case 15 and impregnates the electrode assembly 9. Conductive leads 10 and 13 collect the current generated when the battery is operated, and are attached to the positive and negative electrodes, respectively. The conductive leads 10 and 13 carry the current the positive and negative electrodes to the positive and negative terminals. Although illustrated as having a generally square or rectangular shape, it is understood that the lithium secondary battery can have any shape.

    [0057] The following examples illustrate certain exemplary embodiment of the present invention.

    Synthesis Example of Monomer 1



    [0058] 0.02mol of polyesterpolyol (DR1515 having a Mn=1500 available from DAERYUNG Enterprise Co. Ltd.) was prepared by condensation of ethylene glycol (EG), diethylene glycol (DEG), trimethylolpropane (TMP), and adipic acid. The 0.02mol of polyesterpolyol, 30g of methylene chloride as a reaction solvent, and 0.04mol of triethylamine as a catalyst were placed in a cooling bath and agitated to obtain a first mixed solution. A second mixed solution of 0.04mol of acrylol chloride and 15g methylene chloride was added to the first mixed solution in a dropwise fashion to obtain a third mixed solution. The third mixed solution was heated to 40°C and agitated for 6 hours to deposit salt. The deposited salt was filtered off and methylene chloride was removed by distillation to prepare a target monomer SP1 having a weight average molecular weight of about 25,000 and which is represented by the following Formula 23.



    [0059] In Formula 23, each of l, m, and n is 0, 1 or greater, and is controlled so that the weight average molecular weight of the monomer is about 25,000.

    Synthesis Example of Monomer 2



    [0060] A first mixed solution of 0.04mol of isocyanatoethyl methacrylate and 15g of methylene chloride was added in a dropwise fashion to a second mixed solution of 0.02mol of the polyesterpolyol used in Synthesis Example 1, 30g of methylene chloride as a reaction solvent, and 0.0002mol of dibutyltin dilaurate. The resulting solution was agitated for 6 hours at room temperature and the agitated again for 2 hours at 50°C to deposit salt. The deposited salt was filtered off and methylene chloride was removed by distillation to prepare a target monomer SP2 having a weight average molecular weight of about 25,000 and which is represented by the following Formula 24.



    [0061] In Formula 24, each of l, m, and n is 0, 1 or greater, and is controlled so that the weight average molecular weight of the monomer is about 25,000.

    Synthesis Example of Monomer 3



    [0062] A monomer SP3 having a weight average molecular weight of about 25,000 and which is represented by the following Formula 25 was prepared as in Synthesis Example 1, except that the polyesterpolyol was prepared by condensation of diethylene glycol and adipic acid.



    [0063] In Formula 25, n is 0, 1 or greater, and is controlled so that the weight average molecular weight of the monomer is about 25,000.

    Example 1 (comparative)



    [0064] 7 wt% of the SP1 monomer prepared as in Synthesis Example 1 and 93 wt% of an electrolyte solution comprising 1.3M LiPF6 dissolved in an ethylene carbonate:ethyl methyl carbonate:propylene carbonate:fluorobenzene (30:55:5:15 wt%) mixed solvent were mixed to form a mixed solution. A polymer electrolyte composition was prepared by adding perhexyl pivalate as a polymerization initiator in an amount of 2 wt% based on the weight of the monomers.

    [0065] A lithium battery cell was fabricated by winding the positive electrode, negative electrode and separator to form an electrode assembly and placing the electrode assembly into a battery case. 2.7 g of the polymer electrolyte composition was injected into the battery case, and the battery case was allowed to stand for 16 hours. The resulting battery case was sealed under vacuum and heat-treated in a 70°C oven for 2 hours and 30 minutes to form a lithium secondary battery cell.

    [0066] The positive electrode was fabricated using a LiCoO2 positive active material, ketjen black as a conductive material, and a polyvinylidene fluoride binder in a weight ratio of 96:2:2. The negative electrode was fabricated using artificial graphite as a negative active material and a polyvinylidene fluoride binder in a weight ratio of 94:6.

    Example 2 (comparative)



    [0067] A lithium battery cell was fabricated as in Example 1, except that 5 wt% of the SP1 monomer prepared as in Synthesis Example 1 and 95 wt% of the electrolyte solution were used.

    Example 3 (comparative)



    [0068] A lithium battery cell was fabricated as in Example 1, except that 3 wt% of the SP1 monomer prepared as in Synthesis Example 1 and 97 wt% of the electrolyte solution were used.

    Example 4 (comparative)



    [0069] A lithium battery cell was fabricated as in Example 1, except that 10 wt% of the SP1 monomer prepared as in Synthesis Example 1 and 90 wt% of the electrolyte solution were used.

    Example 5 (comparative)



    [0070] A lithium battery cell was fabricated as in Example 1, except that 20 wt% of the SP1 monomer prepared as in Synthesis Example 1 and 80 wt% of the electrolyte solution were used.

    Example 6 (comparative)



    [0071] A lithium battery cell was fabricated as in Example 1, except that 30 wt% of the SP1 monomer prepared as in Synthesis Example 1 and 70 wt% of the electrolyte solution were used.

    Example 7 (comparative)



    [0072] A lithium battery cell was fabricated as in Example 1, except that 7 wt% of the SP1 monomer prepared as in Synthesis Example 1, 90 wt% of the electrolyte solution, and 3 wt% of a fluoroethylene carbonate additive were used.

    Example 8



    [0073] A lithium battery cell was fabricated as in Example 1, except that 9 wt% of the SP1 monomer prepared as in Synthesis Example 1 as a first monomer, 1 wt% of hexylacrylate (HA) as a second monomer, 87 wt% of the electrolyte solution, and 3 wt% of a fluoroethylene carbonate additive were used.

    Example 9



    [0074] A lithium battery cell was fabricated as in Example 1, except that 6 wt% of the SP1 monomer prepared as in Synthesis Example 1 as a first monomer, 4 wt% of HA as a second monomer, 87 wt% of the electrolyte solution, and 3 wt% of a fluoroethylene carbonate additive were used.

    Example 10



    [0075] A lithium battery cell was fabricated as in Example 1, except that 6 wt% of the SP1 monomer prepared as in Synthesis Example 1 as a first monomer, and 1 wt% of HA as a second monomer were used.

    Example 11



    [0076] A lithium battery cell was fabricated as in Example 1, except that 5 wt% of the SP1 monomer prepared as in Synthesis Example 1 as a first monomer, and 2 wt% of HA as a second monomer were used.

    Example 12



    [0077] A lithium battery cell was fabricated as in Example 1, except that 4 wt% of the SP1 monomer prepared in Synthesis Example 1 as a first monomer, and 3 wt% of HA as a second monomer were used.

    Example 13



    [0078] A lithium battery cell was fabricated as in Example 1, except that 3 wt% of the SP1 monomer prepared as in Synthesis Example 1 as a first monomer, and 4 wt% of HA as a second monomer were used.

    Example 14



    [0079] A lithium battery cell was fabricated as in Example 1, except that 5 wt% of the SP1 monomer prepared as in Synthesis Example 1 as a first monomer, and 2 wt% of butylacrylate as a second monomer were used.

    Example 15



    [0080] A lithium battery cell was fabricated as in Example 1, except that 5 wt% of SP1 monomer prepared as in Synthesis Example 1 as a first monomer, and 2 wt% of isodecylacrylate as a second monomer were used.

    Example 16



    [0081] A lithium battery cell was fabricated as in Example 1, except that 5 wt% of the SP1 monomer prepared as in Synthesis Example 1 as a first monomer, and 2 wt% of ethylene glycol methylether acrylate as a second monomer were used.

    Example 17



    [0082] A lithium battery cell was fabricated as in Example 1, except that 5 wt% of the SP2 monomer prepared as in Synthesis Example 2 as a first monomer, 2 wt% of HA as a second monomer, and 3 wt% of fluoroethylene carbonate as an additive were used.

    Example 18



    [0083] A lithium battery cell was fabricated as in Example 1, except that 5 wt% of the SP3 monomer prepared as in Synthesis Example 3 as a first monomer, 2 wt% of HA as a second monomer, and 3 wt% of fluoroethylene carbonate as an additive were used.

    Comparative Example



    [0084] A lithium battery cell was fabricated as in Example 1 (comparative), except that a polypropylene glycol diacrylate monomer was used.

    [0085] The lithium battery cells according to Examples 8 through 18 and the Comparative Example and Examples 1-7 (comparative) were evaluated by the following methods.

    1) Capacity



    [0086] Each lithium battery cell was charged and discharged according to the following conditions. First, each lithium battery cell was charged at 0.2C to the cut-off condition of 4.2V/20mA and discharged at 0.2C to 2.75V. Second, each lithium battery cell was charged at 0.5C to the cut-off condition of 4.2V/20mA and discharged at 0.2C to 2.75V. Third, the lithium battery cell was charged at 0.5C on the cut-off condition of 4.2V/0.1C and discharged at 0.5C to 3V. The discharge capacity was measured at the third charge-discharge cycle.

    2) Cycle-life characteristics



    [0087] Each lithium battery cell was charged at 1C to the cut-off condition of 4.2V/0.1C and discharged at 1C to 3V. Each battery cell was charged and discharged 300 times. The capacity after the 300th charge-discharge cycle was measured and its percentage of the capacity after the first cycle was recorded.

    3) Measurement of adherence strength


    Peel strength (N/mm)



    [0088] Each electrode was adhered to a separator to form a specimen having a width of 20mm and a length of 100mm. 10mm of the separator was then peeled from the electrode. The peeled ends of the separator were gripped on the top and bottom and the separator was peeled in the opposite direction to measure the peel strength.

    Shear strength (N/mm)



    [0089] A 1.5 cm X 1.5 cm specimen in which the electrode and separator were attached was prepared. The specimen was gripped on the top and bottom and pulled in the opposite direction to measure shear strength.

    4) Strength evaluation


    Strength at normal temperature



    [0090] Each lithium battery cell was charged at 0.2C to the cut-off condition of 4.2V, 20mAh and discharged at 0.2C to the cut-off voltage of 2.75V. Each cell was then charged under constant-current to the cut-off condition of 1C/36min. Each lithium battery cell was measured using the Universal Test Machine (Instron) by the 3 point bending mode. The Maximum Stress (N) when bending at the speed of 5mm/min to 3mm in the length direction was measured.

    Strength after placement at high temperature - I



    [0091] Each lithium battery cell was charged at 0.2C to the cut-off condition of 4.2V, 20mAh, and discharged at 0.2C to the cut-off voltage of 2.75V. Then, each cell was charged at 0.5C to the cut-off condition of 4.2V, 0.1C and placed at 90°C for 4 hours. Each cell was then placed at room temperature for more than 6 hours. The strength of the lithium battery cell after placement at 90°C was measured by the same method used to measure the strength at room temperature.

    Strength after placement at high temperature - 2



    [0092] Each lithium battery cell was charged at 0.2C to the cut-off condition of 4.2V, 20mAh, and discharged at 0.2C to the cut-off voltage of 2.75V. Then, each cell was charged at 1C to the cut-off condition of 4.2V, 20mA, and placed at 80°C for 120 hours and then placed at room temperature for more than 6 hours. The strength of the lithium battery cell after placement at 80°C was measured by the same method used to measure the strength at room temperature.

    [0093] The results of the above measurements are shown in Table 1 below.
    Table 1
     Normal temperature strength (N)High temperature strength -1 (N)High temperature strength -2 (N)Peel strength (N/mm)Shear strenth (N/mm)Capacity (mAh)Cycle-life (%)
    Example 1 (comparative) 75 77 74 0.01 1.0 830 85
    Example 2 (comparative) 70 70 65 0.006 0.85 832 88
    Example 3 (comparative) 65 60 50 0.002 0.74 834 91
    Example 4 (comparative) 90 95 85 0.015 1.07 800 85
    Example 5 (comparative) 105 105 96 0.021 1.11 760 -
    Example 6 (comparative) 110 108 95 0.022 1.15 730 -
    Example 7 (comparative) 90 91 75 0.016 1.1 835 90
    Example 8 170 168 168 0.045 1.45 800 84
    Example 9 171 169 160 0.044 1.40 805 85
    Example 10 146 147 140 0.035 1.35 835 85
    Example 11 145 146 144 0.067 1.36 834 95
    Example 12 147 144 145 0.035 1.33 835 95
    Example 13 110 114 110 0.023 1.14 832 90
    Example 14 146 146 145 0.038 1.34 836 94
    Example 15 145 143 142 0.035 1.29 834 94
    Example 16 120 110 105 0.020 1.10 829 84
    Example 17 146 145 140 0.036 1.35 835 95
    Example 18 147 146 146 0.037 1.37 834 96
    Comp. Example 45 40 - 0.005 - 830 92


    [0094] The lithium secondary batteries of the present invention have comparable battery performance characteristics to lithium secondary batteries employing conventional non-aqueous electrolytes. However, the lithium batteries according to the present invention have significantly improved strength characteristics at room and high temperatures.


    Claims

    1. A polymer electrolyte for a lithium secondary battery comprising:

    a non-aqueous organic solvent;

    a lithium salt; and

    a polymer being obtained by polymerization of a first monomer represented by Formula 1:

            A-polyesterpolyol-B     (1)

    wherein the polyesterpolyol is being obtained by condensation of at least one alcohol having from 2 to 6 OH groups and at least one dicarboxylic acid, the polyesterpolyol having a weight average molecular weight ranging from 100 to 10,000,000, and each of A and B are linked to terminal OH groups of the polyesterpolyol, each of A and B being selected from the group consisting of CH2=CR-C(=O)-, CH2=CR-O-CH2-, CH2=CR-, CH2=CR-O-C(=O)-, CH2=CH-CH2-O-, CH2=CH-S(=O)2-, and CH2=CR-C(=O)-O-CH2CH2-NH-C(=O)-, wherein R is selected from the group consisting of C1 to C10 hydrocarbons and C6 to C10 aromatic hydrocarbons, and a second monomer selected from the group represented by Formulas 2 through 7:

            CH2=CR1-C(=O)-O-X     (2)

            CH2=CR1-O-X     (3)

            CH2=CR1-O-C(=O)-X     (4)

            CH2=CH-CH2-O-X     (5)

            CH2=CH-S(=O)2-X     (6)

            CH2=CR1-C(=O)-O-CH2CH2-NH-C(=O)-O-X     (7)

    or being ethylene glycol methylether acrylate
    wherein R1 is selected from the group consisting of H, C1 to C10 hydrocarbons and C6 to C10 aromatic hydrocarbons, and X is selected from the group consisting of C1 to C20 hydrocarbons, C1 to C20 halogenated hydrocarbons, C6 to C20 aromatic hydrocarbons and C6 to C20 halogenated aromatic hydrocarbons.
     
    2. The polymer electrolyte of claim 1, wherein the at least one alcohol is selected from the group consisting of polyethylene glycol, polypropylene glycol, alkanediol, ethoxylated alkanediol, propoxylated alkanediol, trimethylolpropane, ethoxylated trimethylolpropane, propoxylated trimethylolpropane, ditrimethylolpropane, ethoxylated ditrimethylolpropane, propoxylated ditrimethylolpropane, pentaerythritol, ethoxylated pentaerythritol, propoxylated pentaerythritol, dipentaerythritol, ethoxylated dipentaerythritol, propoxylated dipentaerythritol, bisphenol A, ethoxylated bisphenol A, propoxylated bisphenol A.
     
    3. The polymer electrolyte of claim 1, wherein each of A and B is selected from the group consisting of (meth)acryl groups, vinyl groups, allyl groups, vinylsulfonyl groups, urethane(meth)acryl groups, and combinations thereof.
     
    4. The polymer electrolyte of claim 1, wherein the second monomer is selected from the group consisting of monomers represented by Formula (2) and ethylene glycol methylether acrylate.
     
    5. The polymer electrolyte of claim 1, wherein the lithium salt is selected from the group consisting of LiPF6, LiBF4, lithium bis(oxalato) borate, LiSbF6, LiAsF6, LiClO4, LiCF3SO3, LiN(CF3SO2)2, LiN(C2F5SO2)2, LiAlO4, LiAlCl4, LiN(CxF2x+1SO2)(CyF2y+1SO2) wherein x and y are natural numbers, LiSO3CF3, and combinations thereof.
     
    6. The polymer electrolyte of claim 1, wherein the non-aqueous organic solvent is selected from the group consisting of carbonates, esters, ethers, ketones, nitriles, and combinations thereof.
     
    7. The polymer electrolyte of claim 1, wherein the non-aqueous organic solvent comprises a carbonate-based solvent and an aromatic hydrocarbon-based organic solvent.
     
    8. The polymer electrolyte of claim 7, wherein the aromatic hydrocarbon-based organic solvent is an aromatic compound represented by Formula 9:

    wherein R2 is selected from the group consisting of halogens, C1 to C10 alkyls and combinations thereof, and q is an integer ranging from 0 to 6.
     
    9. The polymer electrolyte of claim 8, wherein the aromatic hydrocarbon-based organic solvent is selected from the group consisting of benzene, fluorobenzene, toluene, fluorotoluene, trifluorotoluene, xylene, and combinations thereof.
     
    10. The polymer electrolyte of claim 1, wherein the polymer electrolyte further comprises an additive selected from the group consisting of vinylene carbonate, divinylsulfone, ethylene sulfite, and carbonates having substituents selected from the group consisting of halogens, cyano (CN) groups and nitro (NO2) groups.
     
    11. The polymer electrolyte of claim 10, wherein the carbonate additive is selected from the group consisting of carbonates having substituents selected from the group consisting of halogens, cyano (CN) groups and nitro (NO2) groups.
     
    12. The polymer electrolyte of claim 11, wherein the carbonate additive is selected from the group consisting of compounds represented by Formula 10:

    wherein X1 is selected from the group consisting of halogens, cyano (CN) groups and nitro (NO2) groups.
     
    13. The polymer electrolyte of claim 12, wherein the carbonate additive is fluoroethylene carbonate.
     
    14. A lithium secondary battery comprising:

    a positive electrode comprising a positive active material capable of intercalating and deintercalating lithium ions;

    a negative electrode including a negative active material capable of intercalating and deintercalating lithium ions; and

    a polymer electrolyte according to any of the claims 1 to 13.


     


    Ansprüche

    1. Polymerelektrolyt für eine sekundäre Lithiumbatterie, aufweisend:

    ein nicht-wässriges, organisches Lösungsmittel;

    ein Lithiumsalz; und

    ein Polymer, das durch Polymerisation eines ersten Monomers, welches durch die Formel 1 dargestellt ist, erhalten wird:

            A-Polyesterpolyol-B     (1)

    wobei das Polyesterpolyol durch Kondensation zumindest eines Alkohols, der 2 bis 6 OH-Gruppen aufweist, und zumindest einer Dicarbonsäure erhalten wird, und wobei das Polyesterpolyol ein Gewichtsmittel der Molmasse im Bereich von 100 bis 10000000 aufweist, wobei A und B jeweils mit endständigen OH-Gruppen des Polyesterpolyols verbunden sind, und wobei A und B jeweils aus der Gruppe bestehend aus CH2=CR-C(=O)-, CH2=CR-O-CH2-, CH2=CR-, CH2=CR-O-C(=O)-, CH2=CH-CH2-O-, CH2=CH-S(=O)2- und CH2=CR-C(=O)-O-CH2CH2-NH-C(=O)- ausgewählt sind, wobei R aus der Gruppe bestehend aus C1- bis C10-Kohlenwasserstoffen und aromatischen C6-bis C10-Kohlenwasserstoffen ausgewählt ist,
    und wobei das Polymer weiterhin durch Polymerisation eines zweiten Monomers, welches aus der Gruppe, die durch die Formeln 2 bis 7 dargestellt ist, erhalten wird:

            CH2=CR1-C(=O)-O-X     (2)

            CH2=CR1-O-X     (3)

            CH2-CR1-O-C(=O)-X     (4)

            CH2=CH-CH2-O-X     (5)

            CH2=CH-S(=O)2-X     (6)

            CH2=CR1-C(=O)-O-CH2CH2-NH-C(=O)-O-X     (7)

    oder welches Ethylenglykolmethyletheracrylat ist,
    wobei R1 aus der Gruppe bestehend aus H, C1- bis C10-Kohlenwasserstoffen und aromatischen C6- bis C10-Kohlenwasserstoffen ausgewählt ist, und wobei X aus der Gruppe bestehend aus C1- bis C20-Kohlenwasserstoffen, halogenierten C1- bis C20-Kohlenwasserstoffen, aromatischen C6- bis C20-Kohlenwasserstoffen und halogenierten, aromatischen C6- bis C20-Kohlenwasserstoffen ausgewählt ist.
     
    2. Polymerelektrolyt nach Anspruch 1, wobei der zumindest eine Alkohol aus der Gruppe bestehend aus Polyethylenglykol, Polypropylenglykol, Alkandiol, ethoxyliertem Alkandiol, propoxyliertem Alkandiol, Trimethylolpropan, ethoxyliertem Trimethylolpropan, propoxyliertem Trimethylolpropan, Ditrimethylolpropan, ethoxyliertem Ditrimethylolpropan, propoxyliertem Ditrimethylolpropan, Pentaerythrit, ethoxyliertem Pentaerythrit, propoxyliertem Pentaerythrit, Dipentaerythrit, ethoxyliertem Dipentaerythrit, propoxyliertem Dipentaerythrit, Bisphenol A, ethoxyliertem Bisphenol A, propoxyliertem Bisphenol A ausgewählt ist.
     
    3. Polymerelektrolyt nach Anspruch 1, wobei A und B jeweils aus der Gruppe bestehend aus (Meth)acrylgruppen, Vinylgruppen, Allylgruppen, Vinylsulfonylgruppen, Urethan(meth)acrylgruppen und Kombinationen davon ausgewählt sind.
     
    4. Polymerelektrolyt nach Anspruch 1, wobei das zweite Monomer aus der Gruppe bestehend aus Monomeren, die durch die Formel (2) dargestellt sind, und Ethylenglykolmethyletheracrylat ausgewählt ist.
     
    5. Polymerelektrolyt nach Anspruch 1, wobei das Lithiumsalz aus der Gruppe bestehend aus LIPF6, LiBF4, Lithium-bis(oxalato)borat, LiSbF6, LiAsF6, LiClO4, LiCF3SO3, LiN(CF3SO2)2, LiN(C2F5SO2)2, LiAlO4, LiAlCl4, LiN(CxF2x+1SO2)(CyF2y+1SO2), LiSO3CF3 und Kombinationen davon ausgewählt ist, wobei x und y natürliche Zahlen sind.
     
    6. Polymerelektrolyt nach Anspruch 1, wobei das nicht-wässrige, organische Lösungsmittel aus der Gruppe bestehend aus Carbonaten, Estern, Ethern, Ketonen, Nitrilen und Kombinationen davon ausgewählt ist.
     
    7. Polymerelektrolyt nach Anspruch 1, wobei das nicht-wässrige, organische Lösungsmittel ein Lösungsmittel auf Basis von Carbonat und ein organisches Lösungsmittel auf Basis von aromatischem Kohlenwasserstoff aufweist.
     
    8. Polymerelektrolyt nach Anspruch 7, wobei das organische Lösungsmittel auf Basis von aromatischem Kohlenwasserstoff ein Aromat ist, der durch die Formel 9 dargestellt ist:

    wobei R2 aus der Gruppe bestehend aus Halogenen, C1- bis C10-Alkylen und Kombinationen davon ausgewählt ist und q eine ganze Zahl von 0 bis 6 ist.
     
    9. Polymerelektrolyt nach Anspruch 8, wobei das organische Lösungsmittel auf Basis von aromatischem Kohlenwasserstoff aus der Gruppe bestehend aus Benzol, Fluorbenzol, Toluol, Fluortoluol, Trifluortoluol, Xylol und Kombinationen davon ausgewählt ist.
     
    10. Polymerelektrolyt nach Anspruch 1, wobei der Polymerelektrolyt weiterhin ein Additiv aufweist, welches aus der Gruppe bestehend aus Vinylencarbonat, Divinylsulfon, Ethylensulfit und Carbonaten, die Substituenten, welche aus der Gruppe bestehend aus Halogenen, Cyano(CN)-Gruppen und Nitro(NO2)-Gruppen ausgewählt sind, aufweisen, ausgewählt ist.
     
    11. Polymerelektrolyt nach Anspruch 10, wobei das Carbonat-Additiv aus der Gruppe bestehend aus Carbonaten, die Substituenten, welche aus der Gruppe bestehend aus Halogenen, Cyano(CN)-Gruppen und Nitro(NO2)-Gruppen ausgewählt sind, aufweisen, ausgewählt ist.
     
    12. Polymerelektrolyt nach Anspruch 11, wobei das Carbonat-Additiv aus der Gruppe bestehend aus Verbindungen, die durch die Formel 10 dargestellt sind, ausgewählt ist:

    wobei X1 aus der Gruppe bestehend aus Halogenen, Cyano(CN)-Gruppen und Nitro(NO2)-Gruppen ausgewählt ist.
     
    13. Polymerelektrolyt nach Anspruch 12, wobei das Carbonat-Additiv Fluorethylencarbonat ist.
     
    14. Sekundäre Lithiumbatterie, aufweisend:

    eine positive Elektrode, die ein positives aktives Material, welches zur Interkalation und Deinterkalation von Lithiumionen ausgebildet ist, aufweist;

    eine negative Elektrode, die ein negatives aktives Material, welches zur Interkalation und Deinterkalation von Lithiumionen ausgebildet ist, aufweist; und

    einen Polymerelektrolyt nach einem der Ansprüche 1 bis 13.


     


    Revendications

    1. Électrolyte polymère pour accumulateur au lithium, comprenant :

    un solvant organique non aqueux ;

    un sel de lithium ; et

    un polymère obtenu par polymérisation d'un premier monomère représenté par la Formule 1 :

            A-polyesterpolyol-B     (1)

    où le polyesterpolyol est obtenu par condensation d'au moins un alcool ayant 2 à 6 groupes OH et d'au moins un acide dicarboxylique, le polyesterpolyol ayant un poids moléculaire moyen en poids compris entre 100 et 10 000 000, et A et B sont chacun attachés aux groupes OH terminaux du polyesterpolyol, chacun de A et B étant choisi dans le groupe formé par CH2=CR-C(=O)-, CH2=CR-O-CH2-, CH2=CR-, CH2=CR-O-C(=O)-, CH2=CH-CH2-O-, CH2=CH-S(=O)2- et CH2=CR-C(=O)-O-CH2CH2-NH-C(=O)-, où R est choisi dans le groupe formé par les hydrocarbures en C1 à C10 et les hydrocarbures aromatiques en C6 à C10,
    et d'un second monomère choisi dans le groupe représenté par les Formules 2 à 7 :

            CH2=CR1-C(=O)-O-X     (2)

            CH2=CR1-O-X     (3)

            CH2=CR1-O-C(=O)-X     (4)

            CH2=CH-CH2-O-X     (5)

            CH2=CH-S(=O)2-X     (6)

            CH2=CR1-C(=O)-O-CH2CH2-NH-C(=O)-O-X     (7)

    ou qui est l'acrylate d'éther méthylique d'éthylèneglycol
    où R1 est choisi dans le groupe formé par H, les hydrocarbures en C1 à C10 et les hydrocarbures aromatiques en C6 à C10, et X est choisi dans le groupe formé par les hydrocarbures en C1 à C20, les hydrocarbures halogénés en C1 à C20, les hydrocarbures aromatiques en C6 à C20 et les hydrocarbures aromatiques halogénés en C6 à C20.
     
    2. Électrolyte polymère selon la revendication 1, dans lequel ledit au moins un alcool est choisi dans le groupe formé par le polyéthylèneglycol, le polypropylène-glycol, un alcanediol, un alcanediol éthoxylé, un alcanediol propoxylé, le triméthylolpropane, le triméthylolpropane éthoxylé, le triméthylolpropane propoxylé, le ditriméthylolpropane, le ditriméthylolpropane éthoxylé, le ditriméthylolpropane propoxylé, le pentaérythritol, le pentaérythritol éthoxylé, le pentaérythritol propoxylé, le dipentaérythritol, le dipentaérythritol éthoxylé, le dipentaérythritol propoxylé, le bisphénol A, le bisphénol A éthoxylé, le bisphénol A propoxylé.
     
    3. Électrolyte polymère selon la revendication 1, dans lequel chacun de A et B est choisi dans le groupe formé par les groupes (méth)acryle, les groupes vinyle, les groupes allyle, les groupes vinylsulfonyle, les groupes uréthanne(méth)acryle, et leurs associations.
     
    4. Électrolyte polymère selon la revendication 1, dans lequel le second monomère est choisi dans le groupe formé par les monomères représentés par la Formule (2) et l'acrylate d'éther méthylique d'éthylèneglycol.
     
    5. Électrolyte polymère selon la revendication 1, dans lequel le sel de lithium est choisi dans le groupe formé par LiPF6, LiBF4, le bis (oxalato) borate de lithium, LiSbF6, LiAsF6, LiClO4, LiCF3SO3, LiN(CF3SO2)2, LiN(C2F5SO2)2, LiAlO4, LiAlCl4, LiN(CxF2x+1SO2)(CyF2y+1SO2) où x et y sont des nombres naturels, LiSO3CF3, et leurs associations.
     
    6. Électrolyte polymère selon la revendication 1, dans lequel le solvant organique non aqueux est choisi dans le groupe formé par les carbonates, les esters, les éthers, les cétones, les nitriles, et leurs associations.
     
    7. Électrolyte polymère selon la revendication 1, dans lequel le solvant organique non aqueux comprend un solvant à base de carbonate et un solvant organique à base d'hydrocarbure aromatique.
     
    8. Électrolyte polymère selon la revendication 7, dans lequel le solvant organique à base d'hydrocarbure aromatique est un composé aromatique représenté par la Formule 9 :

    où R2 est choisi dans le groupe formé par les halogènes, les groupes alkyle en C1 à C10 et leurs associations, et q est un nombre entier compris entre 0 et 6.
     
    9. Électrolyte polymère selon la revendication 8, dans lequel le solvant organique à base d'hydrocarbure aromatique est choisi dans le groupe formé par le benzène, le fluorobenzène, le toluène, le fluorotoluène, le trifluoro-toluène, le xylène et leurs associations.
     
    10. Électrolyte polymère selon la revendication 1, dans lequel l'électrolyte polymère comprend de plus un additif choisi dans le groupe formé par le carbonate de vinylène, la divinylsulfone, le sulfite d'éthylène et les carbonates ayant des substituants choisis dans le groupe formé par les halogènes, les groupes cyano (CN) et les groupes nitro (NO2).
     
    11. Électrolyte polymère selon la revendication 10, dans lequel l'additif du genre carbonate est choisi dans le groupe formé par les carbonates ayant des substituants choisis dans le groupe formé par les halogènes, les groupes cyano (CN) et les groupes nitro (NO2).
     
    12. Électrolyte polymère selon la revendication 11, dans lequel l'additif du genre carbonate est choisi dans le groupe formé par les composés représentés par la Formule 10 :

    où X1 est choisi dans le groupe formé par les halogènes, les groupes cyano (CN) et les groupes nitro (NO2).
     
    13. Électrolyte polymère selon la revendication 12, dans lequel l'additif du genre carbonate est le carbonate de fluoroéthylène.
     
    14. Accumulateur au lithium comprenant :

    une électrode positive comprenant une matière active positive capable d'intercaler et de désintercaler des ions lithium ;

    une électrode négative comprenant une matière active négative capable d'intercaler et de désintercaler des ions lithium ; et

    un électrolyte polymère selon l'une quelconque des revendications 1 à 13.


     




    Drawing