Li-ion-Battery-introduction锂离子电池介绍演示幻灯片.ppt

,单击此处编辑母版文本样式,第二级,第三级,第四级,Page,*,单击此处编辑母版标题样式,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,单击此处编辑母版文本样式,第二级,第三级,第四级,单击此处编辑母版标题样式,Battrey Chemistry Fundamentals and Characteristics,Sinowealth BP wxl,CONTENTS,Introduction,01,Li-ion Battery Fundamentals and Electrical Behavior,02,Monitoring and Safety,04,General Battery Characteristics,03,2,1.2 Li-ion Battery Fundamentals and Electrical Behavior,1.2.1 Battery Structure,1.2.2 Fundamentals,1.2.3 Materials and their influences,1.2.3 Electrical behavior,1.2.4 Equivalent circuit,3,Li-ion Battery Structure,Cylindrical Li-ion Battery structure,Separator,cathode and anode are around the column.,18650,4,Li-ion Battery Structure,Prismatic Li-ion Battery Structure,5,Li-ion Battery Structure,Coin Li-ion Battery structure,6,Li-ion Battery Structure,Thin Film Li-ion Battery Structure,10-100,um thinkness.,for microminiature device,7,Li-ion Battery Structure,8,Li-ion Battery Structure,Li-ion Battery Structure:,Anode,Cathode,Separator,Electrolyte,Enclosure and package,component,material,example,Anode,Li-embedded Transition metal oxides,LiCoO4,LiMnO4,LiCoMnOx,LiFePO4,Cathode,Li-embeddable compound etc.,(synthetic)graphite,Electrolyte,LiPF6 alkyl acid esters,EC,PC,EDC,Separator,polyene porous membrane,PE,PP,PP/PE/PP,Enclosure and package,metal,steel,aluminum,9,Li-ion Battery Performance requirements of anode materials,high specific energy,high specific power,low self-discharge ratio,low cost,long life,high safety,level,10,Capacity Calculation：,1mol,Li,+,Q=,96500C,（F=NA*e=96500C/mol）,1C=1As,Take,LiFePO,4,for example,:,The formula weight of,LiFePO,4,is,157.756 g/mol,(1g/,157.756g/mol,)*,96500,C/mol/3600s,=,170 mAh/g,The formula weight of,Li,Co,O,2,is 97.88,g/mol,(1g/97.88,g/mol,)*,96500,C/mol/3600s,=,274,mAh/g,Li-ion Battery,Capacity Calculation for Anode,11,LiFePO4,LiMnOx,LiCoO2,LiNiO2,LiNiCoMnO2,main component,LiFePO,4,LiMn,2,O,4,LiMnO,2,LiCoO,2,LiNiO,2,LiNiCoMnO,2,ennergy density(,mAh/g,),170,ideal,148,286,274,274,278,130-140,actual,100-120,200,135-140,190-210,155-165,voltage（,V,）,3.2-3.7,3.8-3.9,3.4-4.3,3.6,2.5-4.1,3.0-4.5,cycle life,2000,500,inferior,300,inferior,800,transition metal,very rich,rich,rich,poor,rich,poor,environmantal,non-poisonous,non-poisonous,non-poisonous,radioactivity(Co),poisonous(Ni),poisonous,safety,great,good,good,bad,bad,not bad,temp,(),-20,75,50,low temp stable,-20,55,N/A,-20,55,Li-ion,Battery,anode materials and their peformances,12,LiCoO,2,LiMn,2,O,4,poor safety,high cost,Synthesis difficult,serious attenuation,LiNiO,2,Li-ion battery anode materials,13,Li-ion battery anode material development,power field,communication field,LiFePO,4,LiMn,2,O,4,Li-ternary compound,LiNiO,2,Ni-H,lead-acid,LiCoO,2,power field:,LiFePO4 and LiMn2O4 have the advantages of low cost,safety and heat stablity.,comminocation field:,Li-ternary compound and LiNiO2 have higher,specific energy.,Li-ion battery anode material,14,Li-ion battery,Performance requirements of cathode materials,Li+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 compacted,large diffusion coefficient for Li+diffusion in cells,easy to charge quickly.,15,cathode,materials,ungraphitised,carbon,graphite,stratified structure,Transition metal oxides,silica-based,material,Li,4,Ti,5,O,12,spinel structure,tin,-based,material,metal Li,Li-ion,battery,Cathode materials,16,synthetic graphite,silicon carbon alloy,Li-ion battery,cathode materials performance,cathode materials,capacity,process-ability,temperature stability,disadvantages,graphite carbon,360mAh/g,easy,good,low capacity,Si alloy,2500mAh/g,easy,good,volume change,Sn alloy,800-900mAh/g,hard,bad,bad porformance for high rate discahrge,metal Li,3860mAh/g,easy,bad,dendritic crystal,17,carbon materials potential risk Li,4,Ti,5,O,12,large 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,materials,Li,4,Ti,5,O,12,Fig.Li,4,Ti,5,O,12,SEM photo and its chg/dsg performance,Li-ion battery cathode materials,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 distribution,19,Fig.2 electrolyte product manufacture process,Li-ion battery electrolyte,Electrolyte 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-material,solvent-prepare,purification,fine purification,electrolyte,solution prepare,stir,finished product,20,keep 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-toxic,easy to prepare,low cost,Li-ion battery,Performance requirements of electrolyte materials,21,safety,stability,compatibility with cathode,conductivity,high dielectric constant,low viscosity.,composed by solvent and additive,中文名称,short name,dielectric constant,viscosity(mPas),melting point(),boiling point(),decomposition voltage(V),乙烯碳酸酯,EC,90,1.9,37,238,5.8,丙烯碳酸酯,PC,65,2.5,-49,242,5.8,二甲基碳酸酯,DMC,3.1,0.59,3,90,5.7,二乙基碳酸酯,DEC,2.8,0.75,-43,127,5.5,乙基甲基碳酸酯,EMC,2.9,0.65,-55,108,-,二甲醚,DME,7.2,0.46,-58,84,4.9,solvent,Li-ion battery electrolyte solvent,22,Li-ion battery electrolyte additive,Additive Name,Application,Component,亚乙烯碳酸酯,improve SEI film performance,SO,2,/Co,2,/VC,磷酸三甲酯,improve eletrolyte safety,TMP,冠醚和穴状化合物,improve electrolyte conductivity,ether,etc.,金属氧化物和盐,balance acid concentration,Al,2,O,3,MgO,BaO,Li/Ca,x,CO,y,23,1.,liquid state,solution.high purity solvent,electrolyte(,LiPF,6,),additive.,2.,solid state,ploymer.,polymer lithium ion battery,LIP,.,Li-ion battery electrolyte,electrolyte classify,chemical formula,features,高氯酸锂,LiClO,4,explosive,四氟硼酸锂,LiBF,4,stability,poor conductivity and cyclity,六氟砷酸锂,LiAsF,6,effeciency,stability,but cost high and poisonous,六氟磷酸锂,LiPF,4,good conductivity,poor thermal stability,三氟甲基磺酰,LiN(SO,2,CF,3,),good thermal stability and cyclity,but poor conductivity,双草酸硼酸锂,LiBOB,good thermal stability and chemical stability,but low solubility and poor conductivity,24,play an improtant role in:,keep anode and cathode separate,allow ion to pass through itself and charge to transfer,Li-ion battery separator,25,Li-ion battery separator performance,ability,purpose,performance,position separator,insulation,anode and cathode particles isolation,aviod slef-discharging,internal short circuit,poriness,Li-ion transfer,high conductivity,low internal impendance,chemical stability,no reaction and consumption,long storage life,electrolyte wettability,fully contacted,ion conductivity,long cycle life,mechanical property,in case of crack by force from dendritic crystal or the other.,long storage life,self-protect,pores close when temperature rise,safety,26,porous ploymer thin film（,PP,PE,PP/PE/PP,）,mechanical property,wettablity,pore close temp point and fusing point conflict,non-woven fabrics,Separion,无纺布型,high porosity nanofiber film,Separion,thin film,ploymer electrolyte,solid,gel,Li-ion,Battery,S,eparator,27,Celgard2400,separator，,PP,，,25m,，,37%,porosity,，,0.117m*0.042m,pore size,Li-ion battery separator example,28,Li-ion Battery Characteristics,Chemical Capacity and Energy,Battery Impedance,Usable Capacity,Power Capability,Cycle Life,Durability,Shelf Life,Self-Discharge Properties,29,Li-ion Battery,Chemical Capacity/Energy,Qmax：,Amount of charge can be extracted from the fully charged cell to the end of discharge voltage(EDV).Battery chemical capacity(no load),In Unit of:,Ah/kg,Ah/l,Wh/kg,Wh/l,/l,/kg-protable equipments(phone,pad,etc.),ploymer Li-ion Battery,Ah,Wh-comparing different battery with same chemical materials in Ah,but Wh for different chemical battery.,Fig.x Voltage profile during low-rate discharge of battery,30,Li-ion Battery,Battery Impedance,Battery Impedance：dV=I*R,after transient process,Nyquist plot:,Voltage responses on current of different frequency,A1:impedance,stretching real,value of A2,3,5,A5:0.51s,A6:1000s,Relaxation time,31,Li-ion battery,Battery Impedance,Battery Impedance：dV=I*R,after transient process,Nyquist plot:,Voltage responses on current of different frequency,A1:1000s.,real sesistance stop increasing，,IR drop constant，DC resistance.,Relaxation time,32,Battery Impedance：dV=I*R,after transient process,Nyquist plot:,Voltage responses on current of different frequency,40m 6070m 100m,A1 A2 A3 A4 A5 A6,1000s,NOTE：,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.,Relaxation time increasing，real resistance keep constant but imaginary increacing,as if serially connected capacitor and capatance is huge.,note that cell impedance varies from SOC,resulting from active particals and ions changes.,Equivalent circuit refer to page 6 Fig.3.,Li-ion battery,Battery Impedance,Relaxation time,33,Q,usable,: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 DC,estimate usable capacity in real discharge process,in thermal box,heat exchange,much more close to real usable,capacity,why not test cell temperature directly？,self-heating of cell and,more important,electronic devices,result in enviroment temperature around the cells rising,abundant heat exchange(put in thermal box)is nessanary for monitoring.,Li-ion battery,Usable Capacity,34,Ragone Plot:Power Density(W/kg)-Energy Density(Wh/kg)./kg,/l,/m,2,Energy Density(Wh/kg):,battery ennery for battery one cycle use,Power Density(W/kg):,battery power for battery proviod ennery every unit time,Li-ion battery,Power Capability and Ragone Plot,35,cell aged：chemical capacity loss and impedance increase,chemical capacity loss：,reason：crystal structure of active change,influnce：high and low-rate discharge applications,impedance increase：,primary reason：passivating layer grow and electrolyte loss,influnce：high-rate discharge application.deeper IR drop，usable capacity decrease。,Li-ion battery,Cycle Life,36,Li-ion Battery,Cycle Life,Analyze：,Experimental results-impedance increase influnce is much larger than that of capacity loss.,100cycle later，capcity loss5%，impedance increase60%.,(DC resistance increased but not 1kHz resistance(almost constant),DC resistance is worthy of our attention),internal resistance：R=(V-OCV)/I,37,Shelf life depends on,storage voltage(storage SOC)and storage temperature.,Experimental result：,lead-acid battery benefit from high SOC storage,and Li-ion battery prefer low SOC storage,Aged 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 jam up pores to decrease the conductivity.,current appear and disappear make the passivating layer expansion and shrinkage,the machanical change cause the electrical disconnect.,during same time，cycle aged 510 times larger than storage.,Li-ion Battery Shelf Life(,Storage Life),38,Li-ion Battery Shelf Life(Storage Life),In the same temperature,the lower voltage,the lower battery capacity loss,the longer storage life of the battery.,Under the same voltage condition,the lower temperature,the lower battery capacity loss,the longer storage life of the battery.,Under the same charge current condition,the lower charge voltage,the longer cycle life of the battery.,39,Li-ion battery Self-Discharge,Self-discharge Mechanism:,Parasitic conductance,Dendritic crystal grows in charge process,decreasing the suface of anode.,Saperator will be poked and cracked by more dendritic crystal,leading to electrode direct contect to each other.,Precautions:nanoporous saparators have been used to reduce this effect.,shuttle molecules,some molecules can become oxidized on cathode,diffuse to anode,and become reduced there,and back to cathode.Similar effect of electron transfer.,Precautions:avoid bringing in impurities in cell manufacture process.,utilize:under the high voltage conditon,the redox reaction of shuttle molecules can prevent over charge.,40,Li-ion battery Self-Discharge,Self-discharge Mechanism:,Recombination of oxygen-hydrogen,H2and O2generate by electrolysis of water,gasses then diffuse through the separator and react since saparators are not airtight.Another redox reaction generate which is similar to the effect of electron transfer.,Recombination of oxygen-hydrogen generates heat and becomes noticeable close to the end of charge.,Other redox reactions by impurities in electrolyte.,41,Li-ion battery Self-Discharge,Temperature：,the higher temperature,the higher self-discahrge rate,Temperature rise will accelerate all redox reactions.,Age：,the more age,the higher self-discahrge rate,the age,the more crack of active materials,the higher surface area,the more matters of redox reactions.,Note:,cell structure design,The reactions between electrolyte and electrode always exsit in the process of self-discharge,which makes poor the material activity and changes its structure,leading to decrease the ennergy(voltage)of the cell under the constant capacity.,42,1.4 Monitoring and Safety,1、safety,Li-ion battery safety problems need more anntention:,more activity of Li,reaction with mounts of material,high specific ennergy,Consequence:,Thermal runaway,(热逃逸，热失控),：,The temperature rise,the more additive heat.thermal positive feedback,battery explode(expansion by heat or much more gas),Sources:,Manufacture process.,internal short circuit,metal particles,Age process.,cell imbalance,electrode imbalance,unreasonable operation,over discharge/charge.,crystal structure change,dendritic crystal,internal short circuit,43,1.4 Monitoring and Safety,2、safety problem example,external short circuit,external monitoring device and circuit prevention for safety.,Internal short circuit,Saperator may be poked and cracked by more dendritic crystal,leading to electrode direct contect to each other.manufacturing sector and external monitoring circuit prevention for safety.,gas expansion.,U,nder high current and high temperature condition,electrolysis producing amount of gas.manufacturing sector and external monitoring