HYBRID ELECTRIC VEHICLES- HYBRIDIZATION OF AUTOMOBILE ( Unit- 2)

Architectures of HEVs, series and parallel HEVs, complex HEVs .Plug-in hybrid vehicle, constituents of PHEV, comparison of HEV and PHEV; Fuel Cell vehicles and its constituents.

1. Dr.G.Nageswara Rao
Professor
1
Hybrid Electric Vehicles

2. 2

3. Hybrid Electric Vehicles Topologies
3
(HEV Configurations)

4. 4
Series Hybrid Electric Vehicle

5. 5
Detailed Configuration of Series Hybrid Electric Vehicle

6. 6
Figure 1a: Mode 1, normal driving or acceleration
Figure 1b: Mode 2, light load
Figure 1c: Mode 3, braking or deceleration
Figure 1d: Mode 4, vehicle at stop
B:Battery
E: ICE
F: Fuel tank
G: Generator
M: Motor
P: Power Converter
T: Transmission
(including brakes,
clutches and gears)

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PowerFlowControlinSeriesHybridIntheserieshybridsystem
therearefouroperatingmodesbasedonthepowerflow:
Mode1:Duringstartup(Figurea),normaldrivingoraccelerationoftheseries
HEV,boththeICEandbatterydeliverelectricenergytothepowerconverterwhich
thendrivestheelectricmotorandhencethewheelsviatransmission.
Mode2:Atlightload(Figureb),theICEoutputisgreaterthanthatrequiredto
drivethewheels.Hence,afractionofthegeneratedelectricalenergyisusedto
chargethebattery.Thechargingofthebattertakesplacetillthebatterycapacity
reachesaproperlevel.
Mode3:Duringbrakingordeceleration(Figurec),theelectricmotoractsasa
generator,whichconvertsthekineticenergyofthewheelsintoelectricityandthis,
isusedtochargethebattery.
Mode4:ThebatterycanalsobechargedbytheICEviathegeneratorevenwhen
thevehiclecomestoacompletestop(Figured).

8. 8
Parallel Hybrid Electric Vehicle

9. 9
Figure a: Mode 1, start up Figure b: Mode 2, normal driving
Figure c: Mode 3, braking or deceleration Figure d: Mode 4, light load
B:Battery
E: ICE
F: Fuel tank
G: Generator
M: Motor
P: Power
Converter

10. 10
PowerFlowControlinParallelHybrid
Theparallelhybridsystemhasfourmodesofoperation.Thesefourmodes
ofoperationare
Mode1:Duringstartuporfullthrottleacceleration(Figurea);boththeICE
andtheEMsharetherequiredpowertopropelthevehicle.Typically,the
relativedistributionbetweentheICEandelectricmotoris80-20%.
Mode2:Duringnormaldriving(Figureb),therequiredtractionpoweris
suppliedbytheICEonlyandtheEMremainsinoffmode.
Mode3:Duringbrakingordeceleration(Figurec),theEMactsasa
generatortochargethebatteryviathepowerconverter.
Mode4:Underlightloadcondition(Figured),thetractionpoweris
deliveredbytheICEandtheICEalsochargesthebatteryviatheEM.

11. 11
Series -Parallel Hybrid Electric Vehicle

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Figure a: Mode 1, start up Figure b: Mode 2, acceleration
Figure c: Mode 3, normal drive
Figure d: Mode 4,
braking or deceleration
Figure e: Mode 5,
battery charging during driving
Figure f: Mode 6,
battery charging during standstill

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The operating modes of EM dominated system are:
Mode1:Duringstartup(Figurea),theEMprovidesthetraction
powerandtheICEremainsintheoffstate.
Mode2:Duringfullthrottle(Figureb),boththeICEandEMprovide
thetractionpower.
Mode3:Duringnormaldriving(Figurec),boththeICEandEM
providethetractionpower.
Mode4:Duringbrakingordeceleration(Figured),theEMactsasa
generatortochargethebattery.
Mode5:Tochargethebatteryduringdriving(Figuree),theICE
deliverstherequiredtractionpowerandalsochargesthebattery.The
EMactsasagenerator.
Mode6:Whenthevehicleisatstandstill(Figuref),theICEcan
deliverpowertochargethebatteryviatheEM

14. 14
Complex Hybrid Electric Vehicle

15. 15
Figure a: Mode 1, start up Figure b: Mode 2, accelerationFigure c: Mode 3, normal drive
Figure d: Mode 4
braking or deceleration
Figure e: Mode 5
battery charging during driving
Mode 6,
battery charging during standstill

16. 16
Power Flow Control Complex Hybrid Control
The complex hybrid vehicle configurations are of two types:
Front hybrid rear electric
Front electric and rear hybrid
Boththeconfigurationshavesixmodesofoperation:
Mode1:Duringstartup(Figurea),therequiredtractionpowerisdeliveredbytheEMsandtheengineis
inoffmode.
Mode2:Duringfullthrottleacceleration(Figureb),boththeICEandthefrontwheelEMdeliverthe
powertothefrontwheelandthesecondEMdeliverspowertotherearwheel.
Mode3:Duringnormaldriving(Figurec),theICEdeliverspowertopropelthefrontwheelandtodrive
thefirstEMasageneratortochargethebattery.
Mode4:Duringdrivingatlightload(Figured)firstEMdeliverstherequiredtractionpowertothefront
wheel.ThesecondEMandtheICEareinoffsate.
Mode5:Duringbrakingordeceleration(Figuree),boththefrontandrearwheelEMsactasgeneratorsto
simultaneouslychargethebattery.
Mode6:Auniqueoperatingmodeofcomplexhybridsystemisaxialbalancing.Inthismode(Figuref)
ifthefrontwheelslips,thefrontEMworksasageneratortoabsorbthechangeofICEpower.Throughthe
battery,thispowerdifferenceisthenusedtodrivetherearwheelstoachievetheaxlebalancing.

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Plug-In Hybrid Electric Vehicles (PHEV)

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Plug-In Hybrid Electric Vehicles (PHEV)
Aplug-inhybridelectricvehicle(PHEV)usesabatterytopoweranelectric
motorandusesanotherfuel,suchasgasolineordiesel,topoweraninternal
combustionengine.ThebatterypackinaPHEVisgenerallylargerthanina
standardhybridelectricvehicle.
Thelargerbatterypackallowsthevehicletooperatepredominantlyon
electricityduringshorttrips.Forlongertrips,aPHEVcandrawliquidfuelfrom
itson-boardtanktoprovideadrivingrangesimilartothatofaconventional
vehicle.Anon-boardcomputerdecideswhentousewhichfuelaccordingto
whichmodeallowsthevehicletooperatemostefficiently.
Thebatterycanbechargedbypluggingintoanelectricpowersource,through
regenerativebraking,andbytheinternalcombustionengine.Inregenerative
braking,kineticenergynormallylostduringbrakingiscapturedandstoredin
thebattery

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Plug-inHybridElectricVehicles,orPHEVs,arethenextgenerationofhybrid
electricvehiclesthatarefairlynewtothescenebutarequicktogaintraction
becauseoftheirincreasedefficiency.Theyarealsocalledrange-extendedelectric
vehiclesfortheobviousreasonthatthevehiclesalwayshavegasolineasa
potentialback-upthatcanextendthedrivingrange.Theyareequippedwitha
largerandapowerfulbatterycomparedtoHEVs,whichcanberechargedatthe
electricitygrid.
PHEVsoperateintwodifferentmodesbasedonthechargeofthebattery.Itmostly
useselectricmotortopropeltheenginewhichautomaticallyreducesthefossilfuel
consumption,anditwillonlyswitchtoICEifthebatteryleveldropsbelowtheset
limit.

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Whyplug-inhybrid?
Manycarownerdonotusethecarforbusinesstravel,andtheydonotdrivedaily
morethan50km.forsuchdistanceitisnotnecessarytospendanypetrol,because
thisdistancecanbeeasilyrealizedbyenergyfrombattery,butgreatdisadvantage
ofelectricdriveis,thatthe“empty”batterycannotberechargedinminutesandin
thecaseoflongertrip,thesafetyreturnisnotsure.Alsoinsomeraretripsduring
holidaysetc.cannotberealizedbyelectricvehiclethatmeansyoumusthaveor
purchaseanothercar.Alltheseproblemsaresolvedbyserialhybridwithgreater
battery,whichcanbedrivenfirst50kmfrombatteryonlyandinthecaseoflonger
trip;theengineisstartedandoperatedintheoptimalefficiencyworkpointwith
constantpowerandspeed.Thegeneratedelectricityiseitherusedformotorssupply
orincaseoflowloadissimultaneouslystoredinemptybattery.
ThePHEVmustbeabletoworkinelectricmodeonlyatanyspeed,duringtheshort
tripsunderthedailylimit.ThereforeitmusthavestrongenoughelectricmotorEM
andthisconditionresultsinserialconcepthybrid,whentheICEisnotmechanically
connectedwithwheels,becauseitshelpisnotnecessary

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25. 25
Components of a
Plug-In Hybrid Electric Vehicle
1.Battery (auxiliary)
2.Charge port
3.DC/DC converter
4.Electric generator
5.Electric traction motor
6.Exhaust system.
7.Fuel filler
8.Fuel tank (gasoline)
9.Internal combustion engine
(spark-ignited)
10.On-board charger
11.Power electronics controller
12.Thermal system (cooling)
13.Traction battery pack
14.Transmission

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HowDoPlug-InHybridElectricCarsWork?
Plug-inhybridelectricvehicles(PHEVs)usebatteriestopoweranelectricmotorandanotherfuel,
suchasgasoline,topoweraninternalcombustionengine(ICE).PHEVbatteriescanbecharged
usingawalloutletorchargingequipment,bytheICE,orthroughregenerativebraking.Thevehicle
typicallyrunsonelectricpoweruntilthebatteryisnearlydepleted,andthenthecarautomatically
switchesovertousetheICE
Components of a Plug-In Hybrid Electric Vehicle
Battery(auxiliary):Inanelectricdrivevehicle,thelow-voltageauxiliarybatteryprovideselectricity
tostartthecarbeforethetractionbatteryisengaged;italsopowersvehicleaccessories.
Chargeport:Thechargeportallowsthevehicletoconnecttoanexternalpowersupplyinorderto
chargethetractionbatterypack.
DC/DCconverter:Thisdeviceconvertshigher-voltageDCpowerfromthetractionbatterypackto
thelower-voltageDCpowerneededtorunvehicleaccessoriesandrechargetheauxiliarybattery.
Electricgenerator:Generateselectricityfromtherotatingwheelswhilebraking,transferringthat
energybacktothetractionbatterypack.Somevehiclesusemotorgeneratorsthatperformboththe
driveandregenerationfunctions.
Electrictractionmotor:Usingpowerfromthetractionbatterypack,thismotordrivesthevehicle's
wheels.Somevehiclesusemotorgeneratorsthatperformboththedriveandregeneration
functions.

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Exhaustsystem:Theexhaustsystemchannelstheexhaustgasesfromtheengineoutthrough
thetailpipe.Athree-waycatalystisdesignedtoreduceengine-outemissionswithintheexhaust
system.
Fuelfiller:Anozzlefromafueldispenserattachestothereceptacleonthevehicletofillthetank.
Fueltank(gasoline):Thistankstoresgasolineonboardthevehicleuntilit'sneededbytheengine
Internalcombustionengine(spark-ignited):Inthisconfiguration,fuelisinjectedintoeitherthe
intakemanifoldorthecombustionchamber,whereitiscombinedwithair,andtheair/fuelmixtureis
ignitedbythesparkfromasparkplug.
On-boardcharger:TakestheincomingACelectricitysuppliedviathechargeportandconvertsit
toDCpowerforchargingthetractionbattery.Italsocommunicateswiththechargingequipment
andmonitorsbatterycharacteristicssuchasvoltage,current,temperature,andstateofcharge
whilechargingthepack.
Powerelectronicscontroller:Thisunitmanagestheflowofelectricalenergydeliveredbythe
tractionbattery,controllingthespeedoftheelectrictractionmotorandthetorqueitproduces.
Thermalsystem(cooling):Thissystemmaintainsaproperoperatingtemperaturerangeofthe
engine,electricmotor,powerelectronics,andothercomponents.
Tractionbatterypack:Storeselectricityforusebytheelectrictractionmotor.
Transmission:Thetransmissiontransfersmechanicalpowerfromtheengineand/orelectric
tractionmotortodrivethewheels.

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32. 32
Full hybrid carsPlug-in hybrid
cars
Electric power
Can power the car at
slower speeds
Can power the car in
all uses
Battery size and cost
Smaller, less
expensive
Larger, more
expensive
Recharging Regenerative brakingExternal power source
Gasoline power
(ICE)
Used in most driving
conditions
Used simultaneously
or only when electric
power runs low

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34. 34
Companies of BEV, PHEV and HEV
BEV PHEV HEV
Tesla Model S BMW i3 REX PHEV Audi Q5
Nissan Leaf BEV BMW i8 PHEV Acura ILX Hybrid
Mitsubishi iMiEV BEV Cadillac ELR PHEV Cadillac Escalade Hybrid
BMW i3 BEV GM Chevy Volt PHEV BMW Active Hybrid
Smart EV BEV Porsche PanameraS E PHEV BMW Active Hybrid 5
Ford Focus EV BEV Ford Fusion EnergiPHEV BMW Active Hybrid 7
- Ford CmaxEnergiPHEV Honda Civic Hybrid
- Toyota Prius Plugin PHEV Honda CR-Z Hybrid
- - Hyundai Sonata Hybrid
- - Infiniti Q50 Hybrid
- - Infiniti Q70 Hybrid

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Fuel cell vehicles

36. 36
Fuel cell vehicle Components

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FCEVsuseapropulsionsystemsimilartothatofelectricvehicles,whereenergy
storedashydrogenisconvertedtoelectricitybythefuelcell.Unlike
conventionalinternalcombustionenginevehicles,thesevehiclesproduceno
harmfulemissions.
FCEVsarefuelledwithpurehydrogengasstoredinatankonthevehicle.Similar
toconventionalinternalcombustionenginevehicles,theycanfuelinlessthan
fourminutesandhaveadrivingrangeofover300miles.FCEVsareequipped
withotheradvancedtechnologiestoincreaseefficiency,suchasregenerative
brakingsystemsthatcapturetheenergylostduringbrakingandstoreitina
battery.Majorautomobilemanufacturersareofferingalimitedbutgrowing
numberofproductionfcevtothepublicincertainmarkets,insyncwithwhatthe
developinginfrastructurecansupport.

39. 39
Thegas(H2),alongwithdioxygen(O2)fromthesurroundingair,aresuppliedto
thefuelcell.Thesetwogasesthenundergoanelectrochemicalreactioninsidethe
cell,inturnproducingelectricity,heatandwatervapor(H2O),whichisreleasedin
theformofagasviaasmalltubelocatedunderneaththevehicle.
Afuelcelliscomposedoftwoelectrodes,anelectrolyte,fuel(hydrogen),anda
powersupply.Thereductionandoxidationreactionhappensthroughamulti-step
processinvolvingtheanode,thecathode,andtheelectrolytemembrane.
Atthenegatively-chargedanodesite,hydrogenmoleculesaresplitintoelectrons
andprotons.Theelectronsarethenforcedthroughacircuitwheretheygenerate
anelectriccurrentandexcessheat.Theprotonsgoontotheelectrolyte
membrane.Atthecathode,theprotons,electrons,andoxygencombineto
producewatermolecules.Flowplatesfacilitatethetransferbetweentheanode
andcathode.Becauseanindividualfuelcellonlyproduceslessthan1.16voltsof
electricity,fuelcellstacksareneededtoincreasetheamountofelectricity
generated.

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45. 45
Fuelcellsareatypeofenergyconversiontechnologywhichtakethechemicalenergycontainedwithina
fuelandtransformitintoelectricityalongwithcertainby-products(dependingonthefuelused).[1]It's
importanttonotethatfuelcellsarenotheatengines,sotheycanhaveincrediblyhighefficiencies.However,
whenaheatengineisusedtopowerafuelcell,theheatenginestillhasalimitingthermalefficiency.
Fuelcellscanbeseenasanenergystoragedevice,asenergycanbeinputtocreatehydrogenandoxygen,
whichcanremaininthecelluntilitsuseisneededatalatertime.Inthissensetheyworkmuchlikea
battery.Therearemultipletypesoffuelcells,buttwocommontypesarethesolidoxidefuelcell(SOFC)
andthepolymerelectrolytemembranefuelcell(PEMFC).
Toproduceelectricityinasolidoxidefuelcell,oxygenintheaircombineswithfreeelectronstoform
oxideions.Theoxideionstravelthroughaceramicelectrolyteandreactwithmolecularhydrogentoform
water.Thereactionthatmakeswateralsoreleaseselectronswhichtravelthroughanexternal
electricalcircuit,producingelectricity.
[4]
Thisprocesscanbeseeninfigure1.
Toproduceelectricityinapolymerelectrolytemembranefuelcell,agaseousfuelisinputandreactswitha
catalystmadeofplatinumnanoparticles.Whenmolecularhydrogencomesintocontactwiththis,itsplits
intotwoH
+
ionsandtwoelectrons.Theelectronsareconductedthroughanelectromotiveforceand
electricityisproduced.Thehydrogenionspassthroughaprotonexchangemembrane(alsoknownasa
polymerelectrolyte)whereitreachesthecathodeandcombineswithoxygentoformwater.Thisprocess
cancontinueaslongasthereishydrogenandoxygensuppliedtothecell.
[1]
Figure2showsthisprocessina
PEMFC.
Fuel Cell

46. 46
Solidoxidefuelcell(SOFC).Molecular
oxygenbecomesoxideions(O2-)and
combineswithhydrogentoformwater,
whilesimultaneouslyproducingelectricity
Polymerelectrolytemembranefuelcell(PEMFC).
Molecularhydrogenfuelbecomeshydrogenions
(H+)thattravelthroughapolymerelectrolyte.The
hydrogenionscombinewithoxygentoform
water,whilesimultaneouslyproducingelectricity

47. 47
Incontrasttoconventionalbatteryelectricvehicles,hydrogenfuelcellelectricvehicles
generatetheirenergyusingafuelcellpoweredbyhydrogen,asopposedtorelying
completelyonbatteries.Asamainenergysource,hydrogenisusedforfuelcellelectric
vehicles.Theygeneratenopollutantsfromtheexhaustandemitnogreenhousegasesinto
theatmosphere,makingthemmoreenergyefficientthaninternalcombustionengines.
AsdepictedinFigure,thepropulsiontechniqueiscomparabletothatofabatteryelectric
vehicle,withhydrogenbeingtransformedintoelectricity.Thehydrogengasisstoredinthe
hydrogentankuntilitisrequiredbythefuelcellstack,whichislocatedinsidethevehicle.A
fuelcellstackisadeviceofseparatemembraneelectrodesthatcombinehydrogenand
oxygentogenerateelectricity.DC-DCconvertertransformshigher-voltageDCpower
comingfromthefuelcellstackintothelower-voltageDCpowerrequiredtooperatethe
electronicsandrechargethebatteryofthevehicle.TheDC-ACconvertercontrolsthe
motor'sspeedandtorquebyregulatingtheflowofelectricalenergygeneratedbythefuel
cellstackandthebattery.Asaresult,therotationofthewheelsisperformedandthevehicle
isdrivenbytheelectricmotor.
Working Principle of a Hydrogen Fuel Cell Electric Vehicle

48. 48
Thepolymerelectrolytemembrane(PEM)fuelcellwhereanelectrolytemembraneis
positionedbetweenthecathodeandanode,isthemostpopularkindoffuelcellusedin
hydrogenfuelcellelectricvehicles.Thecathodereceivesoxygenfromtheair,whereasthe
anodereceiveshydrogenfromthehydrogentank.Anelectrochemicalprocesstakesplacein
thefuelcellstack,causingthehydrogenmoleculestosplitintoprotonsandelectrons.After
that,theprotonspassthroughthemembraneandaretransportedtothecathodeandthe
electricvehicleispoweredbyelectronsbeingpushedthroughanexternalcircuit,withthe
electronseventuallyrecombiningtheprotonsonthecathodesidetogenerateanH2O
molecule.
Asaresultoftheinteractionbetweentheprotons,electrons,andoxygenmolecules,onlyheat
andwatervaporarereleasedintotheatmospherefromthisprocess.Severalcatalyststhatare
nano-sizedparticlescanbeusedwithvarioushydrogenfuelcelldesigns.Fuelcellsarevery
effectivesincechemicalenergydoesnothavetobetransformedintothermalenergyand
mechanicalenergy.Fuelcellsreducepollutionintwoways,theyproducefewercarbon
emissionsthanconventionalinternalcombustionenginesandtheywastelessenergyinthe
formofheat.Duetomanypositiveaspects,fuelcellscanbeusedinabroadvarietyof
applications,fromhugefacilitieslikepowerplantstotransportation.

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50. 50
ProsofHydrogenCars:
Fasterrefueling:Itwilltakeonlyafewminutestorefill/refuelthehydrogen
gastankduetoitstime-effectiveandinstantaneousprocess.
Distantrange:Hydrogencarsarenotonlyfasterbutalsoofferadistant
rangewithjustasingletankoffuel.
Zeroemissions:Theonlythingthatahydrogencaremitsiswatervapor,
makingitazero-emissionvehicle.
ConsofHydrogenCars:
Lackofinfrastructure:Withthelimitedrefuelingstationsorlackof
infrastructure,hydrogencarswouldnotbeaviableoption.
Quiteexpensive:Hydrogen-poweredcarsarenotcheap,andtherefueling
chargediffersconsiderablyamongdifferentcountries.
Productionchallenges:Whenitcomestotheproductionofhydrogen,it
canbeenergy-intensiveandmayrelyonvariousnon-renewablesources.

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ProsofElectricCars:
Advancedinfrastructure:Comparedtohydrogencars,electriccarshaveadvanced
infrastructureandchargingstationsinwhichgovernmentsworldwideareinvesting.
Emissionlessandcheaper:Electriccarsrunsilentlyandproducenopollutionor
emissions.Also,electriccarsaremoreaffordable,andthecostofrechargingthe
batteriesisconvenient.
Lowermaintenance:Duetothelackofmovingparts,battery-poweredelectriccars
arereliableandrequirelessmaintenance,resultinginlesscost.
ConsofElectricCars:
Limitedrange:Oneofthemostconsiderabledrawbacksofelectriccarsisthe
limitedrangecomparedtothetimeittakestorechargethebatteries.
Batterylifespan:Thelifespanofthebatteriesislimited,anditbecomesdifficultto
disposeofthemproperly.Itwillbeessentialtoreplacetheoldbatterieswithnew
onesataregularperiod.
Limitedchargingstations:Thechargingorrefuelingstationsarecurrentlyinthe
developmentphase,havingaround1000chargingstations.

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Advantages and Disadvantages of Battery and Hydrogen Fuel Cell Technologies

53. 53
Fuelcellsareatypeofenergyconversiontechnologywhichtakethechemical
energycontainedwithinafuelandtransformitintoelectricityalongwithcertain
by-products(dependingonthefuelused).[1]It'simportanttonotethatfuelcells
arenotheatengines,sotheycanhaveincrediblyhighefficiencies.However,when
aheatengineisusedtopowerafuelcell,theheatenginestillhasalimiting
thermalefficiency.
Fuelcellscanbeseenasanenergystoragedevice,asenergycanbeinputtocreate
hydrogenandoxygen,whichcanremaininthecelluntilitsuseisneededatalater
time.Inthissensetheyworkmuchlikeabattery.Therearemultipletypesoffuel
cells,buttwocommontypesarethesolidoxidefuelcell(SOFC)andthepolymer
electrolytemembranefuelcell(PEMFC).

54. 54
Fuel Cell Working Principle and
Schematic Diagram:
FuelCellWorkingPrincipleexplainsthatitisan
electrochemicaldevicethatconvertschemical
energyofaconventionalfueldirectlyintolow
voltageD.C.electricalenergy.Itisthendescribed
asaprimarybatteryinwhichfuelandoxidizerare
storedexternaltothebatteryandfedtoitwhen
needed.Aschematicdiagramoffuelcellisshown
inFig.Thefuelgasisdiffusedthroughtheanode
andisoxidized,thusreleaseselectronstothe
externalcircuit.Theoxidizerisdiffusedthrough
thecathodeandisreducedbytheelectrons
comingfromtheanodethroughtheexternal
circuit.Thefuelcellkeepspermittingthefuel
moleculetomixwiththeoxidizermolecules,and
allowthetransferofelectronbyametallicpath
thatcontainsaload.

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56. 56
The gases diffuse through the electrodes by undergoing the following reaction.
Whenthetemperatureishigh,theelectrolytematerialactsasasieveandthehydrogen
ionsmigratesthroughthematerial.Anelectricalloadisconnectedbetweentheanodeand
thecathode.Thechemicalreactioninthecathode,theenergyrepresentingtheenthalpyof
combustionoffuelisreleasedandapartofitisavailableforconversionintoelectrical
energy.Thewaterformedisdrawnofffromtheside
Thisfuelcelluseshydrogenasfuelandoxygenasanoxidiser.Atypicalhydrogen-oxygen
fuelcellisshownintheFig.Therearethreechambersseparatedbytwoporouselectrodes,
theanodeandcathode.Themiddlechamberbetweenthetwoelectrodesisfilledwith
electrolyte(strongsolutionofpotassiumhydroxide).Theelectrodessurfacesarechemically
treatedtorepeltheelectrolyteinordertorestricttheflowofpotassiumhydroxidetotheouter
chambers.

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Advantages of fuel cells:
1.Conversionefficiencyishigh.
2.Easyandsimpleconstruction.
3.Requireverylittleattentionandmaintenance.
4.Highpowertoweightratio.
5.Fuelcelldoesnotmakeanynoise.
6.Lessspacerequired.
7.Quickoperation.
8.Canbeinstalledattheusepoint.
Disadvantage of fuel cell:
1.It is very costly.
2.Short service life.
3.Low voltage output.
4.Proper attention is needed while selection of materials.
Applicationoffuelcell:
1.Domesticuse
2.Automotivevehicle
3.Centralpowerstation

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