TW550847B - High performance lithium or lithium ion cell - Google Patents

High performance lithium or lithium ion cell Download PDF

Info

Publication number
TW550847B
TW550847B TW090124700A TW90124700A TW550847B TW 550847 B TW550847 B TW 550847B TW 090124700 A TW090124700 A TW 090124700A TW 90124700 A TW90124700 A TW 90124700A TW 550847 B TW550847 B TW 550847B
Authority
TW
Taiwan
Prior art keywords
group
patent application
item
graphite
scope
Prior art date
Application number
TW090124700A
Other languages
English (en)
Chinese (zh)
Inventor
Dongli Dai
Original Assignee
Du Pont
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US09/684,206 external-priority patent/US6699623B1/en
Application filed by Du Pont filed Critical Du Pont
Application granted granted Critical
Publication of TW550847B publication Critical patent/TW550847B/zh

Links

Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/64Carriers or collectors
    • H01M4/66Selection of materials
    • H01M4/663Selection of materials containing carbon or carbonaceous materials as conductive part, e.g. graphite, carbon fibres
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/05Accumulators with non-aqueous electrolyte
    • H01M10/056Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566Liquid materials
    • H01M10/0567Liquid materials characterised by the additives
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/05Accumulators with non-aqueous electrolyte
    • H01M10/052Li-accumulators
    • H01M10/0525Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/05Accumulators with non-aqueous electrolyte
    • H01M10/056Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0565Polymeric materials, e.g. gel-type or solid-type
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/05Accumulators with non-aqueous electrolyte
    • H01M10/056Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566Liquid materials
    • H01M10/0568Liquid materials characterised by the solutes
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/05Accumulators with non-aqueous electrolyte
    • H01M10/058Construction or manufacture
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/05Accumulators with non-aqueous electrolyte
    • H01M10/058Construction or manufacture
    • H01M10/0585Construction or manufacture of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/13Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/13Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/133Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/64Carriers or collectors
    • H01M4/66Selection of materials
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/64Carriers or collectors
    • H01M4/66Selection of materials
    • H01M4/665Composites
    • H01M4/667Composites in the form of layers, e.g. coatings
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00Electrolytes
    • H01M2300/0017Non-aqueous electrolytes
    • H01M2300/0025Organic electrolyte
    • H01M2300/0028Organic electrolyte characterised by the solvent
    • H01M2300/0037Mixture of solvents
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/36Selection of substances as active materials, active masses, active liquids
    • H01M4/48Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/36Selection of substances as active materials, active masses, active liquids
    • H01M4/48Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/36Selection of substances as active materials, active masses, active liquids
    • H01M4/58Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M6/00Primary cells; Manufacture thereof
    • H01M6/14Cells with non-aqueous electrolyte
    • H01M6/16Cells with non-aqueous electrolyte with organic electrolyte
    • H01M6/162Cells with non-aqueous electrolyte with organic electrolyte characterised by the electrolyte
    • H01M6/166Cells with non-aqueous electrolyte with organic electrolyte characterised by the electrolyte by the solute
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50Manufacturing or production processes characterised by the final manufactured product

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • General Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Inorganic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Composite Materials (AREA)
  • Dispersion Chemistry (AREA)
  • Secondary Cells (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Cell Electrode Carriers And Collectors (AREA)
  • Cell Separators (AREA)
  • Conductive Materials (AREA)
TW090124700A 2000-10-06 2001-10-05 High performance lithium or lithium ion cell TW550847B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US09/684,206 US6699623B1 (en) 2000-04-26 2000-10-06 High performance lithium or lithium ion cell

Publications (1)

Publication Number Publication Date
TW550847B true TW550847B (en) 2003-09-01

Family

ID=24747096

Family Applications (1)

Application Number Title Priority Date Filing Date
TW090124700A TW550847B (en) 2000-10-06 2001-10-05 High performance lithium or lithium ion cell

Country Status (7)

Country Link
EP (1) EP1328996A2 (ko)
JP (2) JP2004511887A (ko)
KR (1) KR20040005831A (ko)
CN (1) CN1468455A (ko)
AU (1) AU2002211378A1 (ko)
TW (1) TW550847B (ko)
WO (1) WO2002031905A2 (ko)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI464940B (zh) * 2009-11-11 2014-12-11 Blackberry Ltd 用於無線行動通信裝置之具有磁性補償結構之低雜訊電池
TWI504046B (zh) * 2013-11-22 2015-10-11 Lan Yang Energy Technology Co Ltd 新穎鋰離子電池

Families Citing this family (30)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4798951B2 (ja) * 2004-03-04 2011-10-19 三洋電機株式会社 非水電解質電池用正極及びこの正極を用いた電池
AU2007240125B2 (en) 2006-04-18 2012-05-24 Commonwealth Scientific And Industrial Research Organisation Flexible energy storage devices
FR2916577B1 (fr) * 2007-05-25 2009-11-27 Commissariat Energie Atomique Verre organique electrolytique, son procede de fabrication et dispositif le comprenant.
CN102124599A (zh) * 2008-05-29 2011-07-13 莱登能源公司 具有离子液体电解质的电化学电池
JP5601474B2 (ja) * 2011-02-28 2014-10-08 株式会社Gsユアサ 鉛蓄電池用負極板及び鉛蓄電池
US8298701B2 (en) 2011-03-09 2012-10-30 Aquion Energy Inc. Aqueous electrolyte energy storage device
CA2829224C (en) * 2011-03-09 2016-10-04 Aquion Energy Inc. Metal-free aqueous electrolyte energy storage device
JP5303057B2 (ja) * 2011-10-27 2013-10-02 株式会社神戸製鋼所 集電体、電極および二次電池
FR2988225B1 (fr) * 2012-03-13 2014-03-28 Hutchinson Anode pour cellule de batterie lithium-ion, son procede de fabrication et cette batterie l'incorporant.
BR112015030347A2 (pt) * 2013-06-05 2017-07-25 Johnson Matthey Plc óxido compósito, processo para a preparação de um óxido compósito, uso de um óxido compósito, composição de titanato de lítio, uso de uma composição, e, bateria de íon de lítio secundária
JP5816999B2 (ja) * 2013-09-25 2015-11-18 国立大学法人 東京大学 アルカリ金属、アルカリ土類金属又はアルミニウムをカチオンとする塩と、ヘテロ元素を有する有機溶媒とを含む電解液の製造方法
JP5965445B2 (ja) 2013-09-25 2016-08-03 国立大学法人 東京大学 非水電解質二次電池
EP3051620A4 (en) * 2013-09-25 2017-04-05 The University of Tokyo Electrolyte solution for electricity storage devices such as batteries and capacitors containing salt, wherein alkali metal, alkaline earth metal or aluminum serves as cations, and organic solvent having hetero element, method for producing same, and capacitor provided with said electrolyte solution
JP5817007B1 (ja) * 2013-09-25 2015-11-18 国立大学法人 東京大学 非水系二次電池
JP5816997B2 (ja) * 2013-09-25 2015-11-18 国立大学法人 東京大学 アルカリ金属、アルカリ土類金属又はアルミニウムをカチオンとする塩と、ヘテロ元素を有する有機溶媒とを含む高粘度電解液
JP5817001B2 (ja) * 2013-09-25 2015-11-18 国立大学法人 東京大学 非水系二次電池
JP5817002B2 (ja) * 2013-09-25 2015-11-18 国立大学法人 東京大学 非水系二次電池
US11011781B2 (en) 2013-09-25 2021-05-18 The University Of Tokyo Nonaqueous electrolyte secondary battery
JP5817000B2 (ja) * 2013-09-25 2015-11-18 国立大学法人 東京大学 アルカリ金属、アルカリ土類金属又はアルミニウムをカチオンとする塩と、ヘテロ元素を有する有機溶媒とを含む電解液群
WO2015045389A1 (ja) * 2013-09-25 2015-04-02 国立大学法人東京大学 アルカリ金属、アルカリ土類金属又はアルミニウムをカチオンとする塩と、ヘテロ元素を有する有機溶媒とを含む、電池、キャパシタ等の蓄電装置用電解液、及びその製造方法、並びに当該電解液を具備するキャパシタ
JP5817006B1 (ja) * 2013-09-25 2015-11-18 国立大学法人 東京大学 非水系二次電池
JP5817005B2 (ja) * 2013-09-25 2015-11-18 国立大学法人 東京大学 非水系二次電池
JP5816998B2 (ja) * 2013-09-25 2015-11-18 国立大学法人 東京大学 アルカリ金属、アルカリ土類金属又はアルミニウムをカチオンとする塩と、ヘテロ元素を有する有機溶媒とを含む電解液
JP5817009B1 (ja) * 2013-09-25 2015-11-18 国立大学法人 東京大学 非水系二次電池
JP5817008B1 (ja) * 2013-09-25 2015-11-18 国立大学法人 東京大学 非水系二次電池
US10581050B2 (en) 2017-06-07 2020-03-03 Robert Bosch Gmbh Battery having a low counter-ion permeability layer
WO2019231892A1 (en) 2018-05-31 2019-12-05 Robert Bosch Gmbh Electrode configuration with a protrusion inhibiting separator
FI20195627A1 (en) * 2019-07-11 2021-01-12 Spindeco Tech Oy Procedure for reducing internal resistance of a battery and battery with reduced internal resistance
CN112242564B (zh) * 2019-07-16 2024-05-10 通用汽车环球科技运作有限责任公司 具有电容器辅助夹层的固态电池
JP7371268B2 (ja) * 2021-05-28 2023-10-30 寧徳時代新能源科技股▲分▼有限公司 リチウムイオン二次電池、電池モジュール、電池パック、及び電気機器

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5494762A (en) * 1992-01-16 1996-02-27 Nippondenso Co., Ltd. Non-aqueous electrolyte lithium secondary cell
US5514493A (en) * 1995-03-06 1996-05-07 Minnesota Mining And Manufacturing Company Perfluoroalkylsulfonates, sulfonimides, and sulfonyl methides, and electrolytes containing them
JPH09306506A (ja) * 1996-05-17 1997-11-28 Nisshinbo Ind Inc 溶融塩電池用集電体、そのための集電材料の製造方法及びその集電体を使用した溶融塩電池
EP1044478A1 (en) * 1997-12-10 2000-10-18 Minnesota Mining And Manufacturing Company Bis(perfluoroalkylsulfonyl)imide surfactant salts in electrochemical systems
US6294289B1 (en) * 1998-08-25 2001-09-25 3M Innovative Properties Company Cyano-substituted methide and amide salts
JP3831550B2 (ja) * 1999-08-16 2006-10-11 三洋電機株式会社 非水電解質電池

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI464940B (zh) * 2009-11-11 2014-12-11 Blackberry Ltd 用於無線行動通信裝置之具有磁性補償結構之低雜訊電池
TWI504046B (zh) * 2013-11-22 2015-10-11 Lan Yang Energy Technology Co Ltd 新穎鋰離子電池
US9263762B2 (en) 2013-11-22 2016-02-16 Lanyang Energy Technology Co., Ltd. Lithium ion batteries

Also Published As

Publication number Publication date
WO2002031905A2 (en) 2002-04-18
JP2004511887A (ja) 2004-04-15
CN1468455A (zh) 2004-01-14
KR20040005831A (ko) 2004-01-16
WO2002031905A3 (en) 2002-10-03
EP1328996A2 (en) 2003-07-23
JP2009043737A (ja) 2009-02-26
AU2002211378A1 (en) 2002-04-22

Similar Documents

Publication Publication Date Title
TW550847B (en) High performance lithium or lithium ion cell
US6699623B1 (en) High performance lithium or lithium ion cell
KR101535733B1 (ko) 고성능 리튬 또는 리튬 이온 전지
CN101740744B (zh) 锂离子二次电池用隔离物以及锂离子二次电池
CN107068973A (zh) 非水电解质二次电池用正极和非水电解质二次电池
WO1998020566A1 (en) Film forming method for lithium ion rechargeable batteries
JP3471238B2 (ja) 非水電解液二次電池の製造方法
JP2010225539A (ja) リチウムイオン二次電池用電極及びリチウムイオン二次電池
US9023521B2 (en) Nonaqueous electrolyte secondary battery
JP4283598B2 (ja) 非水電解質溶液及びリチウムイオン2次電池
WO2019156031A1 (ja) リチウムイオン二次電池用電極、その製造方法、及びリチウムイオン二次電池
CN110071260B (zh) 非水电解质二次电池
JP2010225545A (ja) リチウムイオン二次電池用電極及びリチウムイオン二次電池
TW200522408A (en) Manufacturing method of electrochemical device
KR20190077319A (ko) 다공성 실리콘 물질 및 전도성 중합체 결합제 전극
CN107256979A (zh) 一种基于钛酸锂负极的3v级锂离子动力电池及其制备
WO2023070988A1 (zh) 电化学装置和包含其的电子装置
CN107004853A (zh) 复合阴极和包括复合阴极的锂离子电池组以及复合阴极的制备方法
WO2021250803A1 (ja) 2次電池及びその製造方法
JP6973244B2 (ja) 非水電解質二次電池、および、非水電解質二次電池の製造方法
CN115458707A (zh) 二次电池及用电设备
JP3508514B2 (ja) 有機電解質電池
CN105493319B (zh) 负极活性物质、使用该负极活性物质的负极、以及锂离子二次电池
US20230420679A1 (en) Positive electrode slurry, positive electrode plate and battery comprising the positive electrode plate
WO2024079848A1 (ja) リチウム2次電池及びその製造方法

Legal Events

Date Code Title Description
GD4A Issue of patent certificate for granted invention patent
MM4A Annulment or lapse of patent due to non-payment of fees