Li-ion-Battery-introduction锂离子电池介绍.ppt

Battrey Chemistry Fundamentals and CharacteristicsBattrey Chemistry Fundamentals and CharacteristicsSinowealth BP wxlCONTENTSIntroductionLi-ion Battery Fundamentals and Electrical BehaviorMonitoring and SafetyGeneral Battery Characteristics Page 21.2 Li-ion Battery Fundamentals and Electrical Behavior1.2 Li-ion Battery Fundamentals and Electrical Behavior1.2.1 Battery Structure1.2.2 Fundamentals1.2.3 Materials and their influences1.2.3 Electrical behavior1.2.4 Equivalent circuitPage 3Li-ion Battery StructureLi-ion Battery StructureCylindrical Li-ion Battery structureSeparator,cathodeandanodearearoundthecolumn.Page 418650Li-ion Battery StructurePrismatic Li-ion Battery StructurePage 5Li-ion Battery StructureCoin Li-ion Battery structurePage 6Li-ion Battery StructureThin Film Li-ion Battery Structure10-100umthinkness.formicrominiaturedevicePage 7Li-ion Battery StructureLi-ion Battery StructurePage 8Li-ion Battery Structure Li-ion Battery Structure:Li-ion Battery Structure:Anode Anode CathodeCathode Separator Separator Electrolyte Electrolyte Enclosure and packageEnclosure and packagecomponentmaterialexampleAnodeLi-embedded Transition metal oxidesLiCoO4,LiMnO4,LiCoMnOx,LiFePO4CathodeLi-embeddable compound etc.(synthetic)graphiteElectrolyteLiPF6 alkyl acid estersEC,PC,EDCSeparatorpolyene porous membranePE,PP,PP/PE/PPEnclosure and packagemetalsteel,aluminumPage 9Li-ion Battery Performance requirements of anode materialsLi-ion Battery Performance requirements of anode materialshigh specific energyhigh specific powerlow self-discharge ratiolow costlong lifehigh safety levelPage 10Capacity CalculationCapacity Calculation：1mol1mol LiLi+,Q=+,Q=96500C96500C（F=NA*e=96500C/mol F=NA*e=96500C/mol）1C=1As1C=1AsTake Take LiFePOLiFePO4 4 for examplefor example:The formula weight of The formula weight of LiFePOLiFePO4 4 is is 157.756 g/mol,157.756 g/mol,(1g/(1g/157.756g/mol157.756g/mol)*)*9650096500C/mol/3600s C/mol/3600s=170 mAh/g170 mAh/gThe formula weight of The formula weight of LiLiCoCoO O2 2 is 97.88is 97.88 g/mol,g/mol,(1g/97.88(1g/97.88g/molg/mol)*)*9650096500C/mol/3600s C/mol/3600s=274274 mAh/g mAh/gLi-ion Battery Li-ion Battery Capacity Calculation for AnodeCapacity Calculation for AnodePage 11LiFePO4LiMnOxLiCoO2LiNiO2LiNiCoMnO2main componentLiFePO4LiMn2O4LiMnO2LiCoO2LiNiO2LiNiCoMnO2ennergy density(mAh/g)170 ideal148286274274278130-140 actual100-120200135-140190-210155-165voltage（V）3.2-3.73.8-3.93.4-4.33.62.5-4.13.0-4.5cycle life2000500inferior300inferior800transition metalvery richrichrichpoorrichpoorenvironmantalnon-poisonousnon-poisonousnon-poisonousradioactivity(Co)poisonous(Ni)poisonoussafetygreatgoodgoodbadbadnot badtemp()-207550low temp stable-20 55N/A-20 55Li-ion Li-ion BatteryBattery anode materials and their peformancesanode materials and their peformancesPage 12LiCoO2LiMn2O4poor safety,high costSynthesis difficult serious attenuationLiNiO2Li-ion battery anode materialsLi-ion battery anode materialsPage 13Li-ion battery anode material developmentLi-ion battery anode material developmentpower fieldcommunication fieldLiFePO4LiMn2O4Li-ternary compoundLiNiO2Ni-Hlead-acidLiCoO2power field:LiFePO4 and LiMn2O4 have the advantages of low cost,safety and heat minocation field:Li-ternary compound and LiNiO2 have higher specific energy.Li-ion battery anode materialPage 14Li-ion batteryLi-ion battery Performance requirements of cathode materialsPerformance requirements of cathode materialsLi+can be embed and seperated rapidly.good reversibility of Li+reaction with seldom crystal structure change.weak electric potential change in the reaction process.good surface texture(Solid Electrolyte Interface Film,SEI)stability and compactedlarge diffusion coefficient for Li+diffusion in cells,easy to charge quickly.Page 15cathode materialsungraphitisedcarbongraphitestratifiedstructureTransition metal oxidessilica-basedmaterialLi4Ti5O12spinel structuretin-basedmaterialmetal LiLi-ion Li-ion batterybattery Cathode materialsCathode materialsPage 16synthetic graphitesilicon carbon alloyLi-ion battery cathode materials performancecathode materialscapacityprocess-abilitytemperature stabilitydisadvantagesgraphite carbon360mAh/geasygoodlow capacitySi alloy2500mAh/geasygoodvolume change Sn alloy800-900mAh/ghardbadbad porformance for high rate discahrgemetal Li3860mAh/geasybaddendritic crystalPage 17carbon materials potential risk Licarbon materials potential risk Li4 4TiTi5 5OO1212large mount of capacity,less expension,long cycle life and storage life,surpport quick charge.etc.Metal lithium is deposited on the carbon surface.It can explosively react with a variety of materials.Burning,explode and gas expansion are all protential safety problems.carbon materialsLi4Ti5O12Fig.Li4Ti5O12 SEM photo and its chg/dsg performanceLi-ion battery cathode materialsPage 18二次锂电池正负极材料电压-容量分布图Voltage versus capacity for positive-and negative-electrode materials presently used or under serious considerations for the next generation of rechargeable Li-based cells.Li-ion battery electrode Voltage-Capacity distributionLi-ion battery electrode Voltage-Capacity distributionPage 19Fig.2 electrolyte product manufacture processLi-ion battery electrolyteElectrolyte is one of four major part of the Li-ion battery,which plays an important role in Li+transfer and has an effect on Capacity,work temperature range cycle and safety of the battery.Electrolyte is usually 15%of the total weight and 32%of total volume,and its purity is worth attention in the manufacturing process.raw-materialsolvent-preparepurificationfine purificationelectrolytesolution preparestirfinished productPage 20keep liquid state in large temperature range,high Li+conductivity(10-2S/cm).good chemical and heat stability,hard to evaporation and reaction with others.high protential up to 4.5V(vs.Li/Li+)。non-toxiceasy to prepare,low costLi-ion battery Performance requirements of electrolyte materialsPage 21 safety,stability,compatibility with cathode,conductivity,high safety,stability,compatibility with cathode,conductivity,high dielectric constant,low viscosity.dielectric constant,low posed by solvent and additivecomposed by solvent and additive中文名称short namedielectric constantviscosity(mPas)melting point()boiling point()decomposition voltage(V)乙烯碳酸酯EC901.9372385.8丙烯碳酸酯PC652.5-492425.8二甲基碳酸酯DMC3.10.593905.7二乙基碳酸酯DEC2.80.75-431275.5乙基甲基碳酸酯EMC2.90.65-55108-二甲醚DME7.20.46-58844.9solventLi-ion battery electrolyte solventPage 22Li-ion battery electrolyte additiveAdditive NameApplicationComponent亚乙烯碳酸酯improve SEI film performanceSO2/Co2/VC磷酸三甲酯improve eletrolyte safetyTMP冠醚和穴状化合物improve electrolyte conductivityether,etc.金属氧化物和盐balance acid concentrationAl2O3,MgO,BaO,Li/CaxCOyPage 231.liquid state,solution.high purity solvent,electrolyte(LiPF6),additive.2.solid state,ploymer.polymer lithium ion battery,LIP.Li-ion battery electrolytePage 24electrolyte classifychemical formulafeatures高氯酸锂LiClO4explosive四氟硼酸锂LiBF4stability,poor conductivity and cyclity六氟砷酸锂LiAsF6effeciency,stability,but cost high and poisonous六氟磷酸锂LiPF4good conductivity,poor thermal stability三氟甲基磺酰LiN(SO2CF3)good thermal stability and cyclity,but poor conductivity双草酸硼酸锂LiBOBgood thermal stability and chemical stability,but low solubility and poor conductivityplay an improtant role in:keep anode and cathode separateallow ion to pass through itself and charge to transferLi-ion battery separatorPage 25Li-ion battery separator performanceLi-ion battery separator performanceabilitypurposeperformanceposition separator,insulationanode and cathode particles isolation aviod slef-discharging,internal short circuitporinessLi-ion transferhigh conductivity,low internal impendancechemical stabilityno reaction and consumptionlong storage lifeelectrolyte wettabilityfully contactedion conductivitylong cycle lifemechanical propertyin case of crack by force from dendritic crystal or the other.long storage lifeself-protectpores close when temperature risesafetyPage 26porous ploymer thin film（PP,PE,PP/PE/PP）mechanical property,wettablity,pore close temp mechanical property,wettablity,pore close temp point and fusing point conflictpoint and fusing point conflictnon-woven fabrics,Separion Separion 无纺布型无纺布型high porosity nanofiber filmSeparion thin filmploymer electrolytesolid,gelsolid,gelLi-ion Battery SeparatorPage 27Celgard2400 separator，PP，25m，37%porosity，0.117m*0.042m pore size Li-ion battery separator exampleLi-ion battery separator examplePage 28Li-ion Battery CharacteristicsChemical Capacity and EnergyBattery ImpedanceUsable CapacityPower CapabilityCycle Life,Durability,Shelf LifeSelf-Discharge PropertiesPage 29Li-ion BatteryLi-ion Battery Chemical Capacity/EnergyQmax：Amount of charge can be extracted from the fully charged cell to the end of Amount of charge can be extracted from the fully charged cell to the end of discharge voltage(EDV).Battery chemical capacity(no load)discharge voltage(EDV).Battery chemical capacity(no load)In Unit of:Ah/kg,Ah/l,Wh/kg,Wh/l Ah/kg,Ah/l,Wh/kg,Wh/l/l,/kg-protable equipments(phone,pad,etc.),/l,/kg-protable equipments(phone,pad,etc.),ploymer Li-ion Batteryploymer Li-ion Battery Ah,Wh-comparing different battery with same Ah,Wh-comparing different battery with same chemical materials in Ah,but Wh for different chemical materials in Ah,but Wh for different chemical battery.chemical battery.Fig.x Voltage profile during low-rate discharge of batteryPage 30Li-ion Battery Li-ion Battery Battery Impedance Battery ImpedanceBattery Impedance：dV=I*R,after transient processNyquist plot:Voltage responses on current of different frequencyVoltage responses on current of different frequencyA1:1ms.high frequencyA1:impedance,stretching real =impedance,stretching real value of A2,3,5 value of A2,3,5A5:0.51sA5:0.51sA6:1000sA6:1000sRelaxation timePage 31Li-ion battery Li-ion battery Battery Impedance Battery ImpedanceBattery Impedance：dV=I*R,after transient processNyquist plot:Voltage responses on current of different frequency Voltage responses on current of different frequencyA1:1ms.A1:1000s.A6:1000s.real sesistance stop increasingreal sesistance stop increasing，IR drop constantIR drop constant，DC resistance.DC resistance.Relaxation timePage 32Battery Impedance：dV=I*R,after transient processNyquist plot:Voltage responses on current of different frequencyVoltage responses on current of different frequency40m 6070m 100m40m 6070m 100m A1 A2 A3 A4 A5 A6 A1 A2 A3 A4 A5 A6 1000s 1000sNOTENOTE：Cell makers often report cell impendance at 1kHz,its not real cell resistance.real resistance(DC Cell makers often report cell impendance at 1kHz,its not real cell resistance.real resistance(DC resistance)is 2.7 times larger than that at 1kHz.resistance)is 2.7 times larger than that at 1kHz.Relaxation time increasingRelaxation time increasing，real resistance keep constant but imaginary increacing,as if serially real resistance keep constant but imaginary increacing,as if serially connected capacitor and capatance is huge.connected capacitor and capatance is huge.note that cell impedance varies from SOC,resulting from active particals and ions changes.note that cell impedance varies from SOC,resulting from active particals and ions changes.Equivalent circuit refer to page 6 Fig.3.Equivalent circuit refer to page 6 Fig.3.Li-ion battery Li-ion battery Battery Impedance Battery ImpedanceRelaxation timePage 33Qusable:battery voltages.fully charged voltage,end of discharge voltage。Cell voltage depending on SOC and discharge current(IR drop).IR drop observed take about 500s.(Nyquist plot 1000s)IR drop:current，temperature，cyclelife，different from diffferent SOC.Note:Do not estimate IR drop by resistance from cell makers.1kHz vs DCNote:Do not estimate IR drop by resistance from cell makers.1kHz vs DC estimate usable capacity in real discharge processestimate usable capacity in real discharge process in thermal box,heat exchange,in thermal box,heat exchange,much more close to real usable much more close to real usable capacity capacitywhy not test cell temperature directlywhy not test cell temperature directly？self-heating of cell and,more important,electronic devices self-heating of cell and,more important,electronic devices result in enviroment temperature around the cells rising,result in enviroment temperature around the cells rising,abundant heat exchange(put in thermal box)is nessanary for monitoring.abundant heat exchange(put in thermal box)is nessanary for monitoring.Li-ion battery Li-ion battery Usable Capacity Usable CapacityPage 34Ragone Plot:Power Density(W/kg)-Energy Density(Wh/kg)./kg,/l,/m2Energy Density(Wh/kg):battery ennery for battery one cycle usebattery ennery for battery one cycle usePower Density(W/kg):battery power for battery proviod ennery battery power for battery proviod ennery every unit timeevery unit timeLi-ion battery Li-ion battery Power Capability and Ragone Plot Power Capability and Ragone PlotPage 35cell aged：chemical capacity loss and impedance increasechemical capacity loss：reasonreason：crystal structure of active changecrystal structure of active changeinflunceinflunce：high and low-rate discharge applicationshigh and low-rate discharge applicationsimpedance increase：primary reasonprimary reason：passivating layer grow and passivating layer grow and electrolyte losselectrolyte lossinflunceinflunce：high-rate discharge application.deeper IR high-rate discharge application.deeper IR dropdrop，usable capacity decreaseusable capacity decrease。Li-ion battery Li-ion battery Cycle Life Cycle LifePage 36Li-ion Battery Li-ion Battery Cycle LifeCycle LifeAnalyze：Experimental results-impedance increase influnce is much larger than that of capacity loss.100cycle later100cycle later，capcity loss5%capcity loss5%，impedance impedance increase60%.increase60%.(DC resistance increased but not 1kHz resistance(almost constant),DC resistance is(DC resistance increased but not 1kHz resistance(almost constant),DC resistance is worthy of our attention)worthy of our attention)internal resistanceinternal resistance：R=(V-OCV)/IR=(V-OCV)/IPage 37Shelf life depends on storage voltage(storage SOC)and storage temperature.Experimental result：lead-acid battery benefit from high SOC lead-acid battery benefit from high SOC storage,and Li-ion battery prefer low SOC storagestorage,and Li-ion battery prefer low SOC storageAged analyzed is similar to that of cycle life,current exsitance accelarate the aged and parastic reaction current cause cracking of passivating layer,and the layer regrow will use up some active Li,the extra reaction particles will current cause cracking of passivating layer,and the layer regrow will use up some active Li,the extra reaction particles will jam up pores to decrease the conductivity.jam up pores to decrease the conductivity.current appear and disappear make the passivating layer expansion and shrinkage,the machanical change cause the current appear and disappear make the passivating layer expansion and shrinkage,the machanical change cause the electrical