Page - 73 - in Emerging Technologies for Electric and Hybrid Vehicles

Energies 2017,10, 1217 14.Outcomes Thegoalof thispaper is to focusonthekeycomponentsofEV.Major technologies indifferent sectionsarereviewedandthefuture trendsof thesesectorsarespeculated. Thekeyfindingsof this papercanbesummarizedas follows: • EVscanbeclassifiedasBEV,HEV,PHEV,andFCEV.BEVsandPHEVsare thecurrent trends. FCEVscanbecomemainstreaminfuture. Lowcost fuelcellsare themainprerequisite for that and there is need ofmore research tomake that happen. There are also strong chances for BEVstobe themarketdominatorswithampleadvancement inkeytechnologies; energystorage andchargingsystemsbeing twomain factors. CurrentlyFCVsappear tohave little chance to becomeubiquitous, thesemayfindpopularity innichemarkets, forexample, themilitaryand utilityvehicles. • EVscanbe frontwheeldrive, rearwheeldrive, evenall-wheeldrive. Different configurations areapplieddependingontheapplicationof thevehicle. Themotorcanalsobeplaced inside the wheel of thevehiclewhichoffersdistinct advantages. This configuration isnot commercially abundantnow,andhasscopes formorestudyto turn it intoaviableproduct. • ThemainHEVconfigurationsareclassifiedasseries,parallel,andseries-parallel. Currentvehicles areusing theseries-parallel systemmainlyas it canoperate inbothbattery-onlyandICE-only modes,providingmoreefficiencyandless fuel consumptionthantheother twosystems. • CurrentlyEVsusebatteries as themainenergy source. Battery technologyhasgone through significantchanges, the lead-acid technology is longgone,as is theNiMHtype. Li-ionbatteries are currently in use, but even they are not capable enough to provide the amount of energy requiredtoappease theconsumerssuffering from‘rangeanxiety’ inmostcases. Therefore the mainfocusof research in thisareahas tobecreatingbatterieswithmorecapacity,andalsowith betterpowerdensities.Metal-airbatteriescanbethedirectionwhere theEVmakerswillhead towards. Lithium-sulfurbatteryandadvancedrechargeablezincbatteriesalsohavepotential providebetterEVs.Nevertheless, lowcostenergysourceswillbesoughtafteralwaysasESScost isoneof themajorcontributors tohighEVcost. • Ultracapacitorsareconsideredasauxiliarypowersourcesbecauseof theirhighpowerdensities. If coupledwithbatteries,ultracapacitorsproduceahybridESSthatcansatisfysomerequirements demanded from an ideal source. Flywheels are also being used, especially because of their compactbuildandcapability to storeanddischargepowerondemand. Fuel cells canalsobe usedmore in the future ifFCVsgainpopularity. • Different types ofmotors can be employed for EVuse. Theprominent ones can be listed as inductionmotor, permanentmagnet synchronousmotor, and synchronous reluctancemotor. Inductionmotorsarebeingextensively thesedays, theycanalsodominate in futurebecauseof their independenceonrare-earthmaterialpermanentmagnets. • EVs can be chargedwithACorDC supply. There are different voltage levels and they are designatedaccordingly.Highervoltage levelsprovidefastercharging.DCsuppliesnegate the needofrectificationfromAC,whichreducesdelayandloss.However,with increasedvoltage level, thepressureonthegridincreasesandcangiverisetoharmonicsaswellasvoltageimbalance inanunsupervisedsystem.Therefore, thereareamplechancesofresearchinthefieldofmitigating theproblemsassociatedwithhigh-voltagecharging. • Twochargerconfigurationsaremainlyavailablenow:CCSandCHAdeMO.These twosystems arenotcompatiblewitheachotherandeachhasanumberofautomakerssupporting them.Tesla also brought their own ‘supercharger’ system,whichprovides a faster charging facility. It is notpossible todeterminenowwhichoneof thesewillprevail,or ifbothwill co-exist, technical study isneededtofindout themostusefuloneof theseconfigurationsorways tomake them compatiblewitheachother. 73