Seite - 24 - in Emerging Technologies for Electric and Hybrid Vehicles

Energies 2017,10, 1217 (a) (b) (c) (d) Figure28. Inductiveequalizerconfigurations: (a)Basic; (b)Cuk; (c)Transformerbased; (d)Multiple transformersbased. Excessenergy is transferredto lowerenergycellsbyusing inductors. Lithium-ion batteries are being used everywhere these days. It has replaced the lead-acid counterpart and became amature technology itself. Their popularity can be justified by the fact that best-sellingEVs, for example,NissanLeaf andTeslaModel S—all use these batteries [53,54]. Batteryparametersof somecurrentEVsare shown inTable10. Lithiumbatteries alsohave lotsof scopeto improve[55]. Betterbattery technologieshavebeendiscoveredalready,but theyarenotbeing pursuedbecauseof theexorbitantcostsassociatedwith their researchanddevelopment, so it canbe said that, lithiumbatterieswilldominate theEVsceneforquitesometimetocome. Table10.BatteryparametersofsomecurrentEVs.Data from[5]. Model TotalEnergy(kWh) UsableEnergy(kWh) UsableEnergy(%) i3 22 18.8 85 C30 24 22.7 95 B-Class 36 28 78 e6 61.4 57 93 RAV4 41.8 35 84 4.2.Ultracapacitors (UCs) UCshave twoelectrodes separatedby an ion-enriched liquiddielectric. Whenapotential is applied, thepositiveelectrodeattracts thenegative ionsandthenegativeelectrodegathers thepositive ones. Thechargesget storedphysicallystoredonelectrodes thiswayandprovideaconsiderablyhigh powerdensity.Asnochemical reactions takeplaceontheelectrodes,ultra- capacitors tendtohavea longcycle life;but theabsenceofanychemical reactionalsomakes themlowinenergydensity [35]. 24