Lab Report Worksheet: How Does a Fuel Cell Car Work?
LabSection(orDay-Time):____Monday-8:00am_____GroupNumber:____2____Due
Date:___11/20/23___Name(s):__GenevieveOakes,ClintAllen,KunalSharma,andMeshari
Alluqmani_____
1. Definethefollowingterms:
a. Anode(Includeexplanationofwhattypeofprocessoccursattheanode.)
Theelectrodewhereoxidationreactionoccurs.
b. Cathode(Includeexplanationofwhattypeofprocessoccursatthecathode.)
Theelectrodewherereductionreactionoccurs.
c. Catalyst(Includeexplanationofwhatacatalystdoes.)
Asubstancethatspeedsupthechemicalreactionwithoutgettinguseduporchanging
thechemicalformulas.
d. Electrolysis
Whenelectricityisusedtosplitasubstanceintoitscomponents.
e. Fuelcell
Afuelcellislikeacleanandefficientpowergeneratorthatproduceselectricitythrough
achemicalreactionbetweenfuelandoxygen,typicallywithoutcombustion.
2. WhatisaPEM?Whatdoesitdoandwhyisitimportant?
PEMstandsforProtonExchangeMembrane,anditplaysacrucialroleinproton
exchangemembranefuelcells.ThePEMservesastheelectrolytethatfacilitatesthe
electrochemicalreactionbetweenhydrogenandoxygenanditsabilitytoconduct
protonsiscrucialforthefunctioningofthefuelcell.Itenablesthemigrationofprotons
acrossthecell,creatinganelectriccurrent.
3. WhattworeactantsarenecessaryforaPEMhydrogenfuelcelltoproduce
electricity?
Hydrogengasandoxygengas
2H2+O →2H O+Electricity
2 2
4. Whatistheonlyexhaustproducedbyafuelcell? ________________
Watervapor
5. Whatisthepurposeofafuelcellstack?
Afuelcellstackservesasthecorecomponentofafuelcellsystemandplaysacrucial
roleingeneratingelectricalpowerthroughtheelectrochemicalreactionbetweenfuel
andoxygen.
Charging and Discharging of Fuel Cell for Fuel Cell Car:
6. Fillinyourdatabelowandanswerthefollowingquestions:
Table 1. ChargingofFuelCellCar.
Initial volume
marking of cylinder
(mL)
Final Volume at
full cylinder
(mL)
Time reach full
cylinder
(bubbles releasing)
(s)
Label as Anode
or Cathode
H 2 Side
2mL
22
377
Anode
O Side
2
2mL
22
740
Cathode
a. ElectrochemicalReactionsforCharging-
AnodeHalf-reaction:2H₂(g)→4e−+4H+(aq)
CathodeHalf-reaction:O O(l)₂(g)+4e−+4H+(aq)→2H₂
OverallReaction:2H O(l)₂(g)+O₂(g)→2H₂
a. Whichgascylinderfilledupfirst?Why?
TheHydrogensidefilledupfirstbecausetherearetwiceasmanyhydrogenatoms
producedasoxygeninthereaction
7. Fillinyourdatabelowandanswerthefollowingquestions:
Table 2.OperationofFuelCellCar.
Initial volume
marking of
cylinder (mL)
Final Volume at
full Discharge
(mL)
Time to full
Discharge (s)
Label as
Anode or
Cathode
H Side2
22
0
191s
Anode
O Side2
22
11
191s
Cathode
a. ElectrochemicalReactionsforDischarging-
AnodeHalf-reaction:2H,→4H+4e-
CathodeHalf-reaction:O2+4e-→2O
OverallReaction:H2+O2→2H2O
b. Howmuchofeachgasinthecylinderswasconsumed?Hypothesizewhatmay
haveoccurredtomakethecarstoprunningbasedonyourobservations.
Allofthehydrogengasandhalfoftheoxygengaswasconsumed.Thereactionlikely
stoppedbecauseitranoutofhydrogengastoreactwiththeoxygengastocreatewater
vaporandelectricity.
8. WhatisthedifferencebetweentheOverall Reaction occurringduringcharging
vsdischargingsteps?
Theoverallreactionisbetweenananodeandacathode,causingareleaseofpositive
energy,causingpowertobeproduced
9. WhataretwodifferencesbetweentheAnode and Cathode Half-Reactions
occurringduringthechargingvsdischargingsteps?
Whilecharging,theanodeisoxidizedandthecathodeisreduced,indischargingthe
oppositeoccurs.Theanodeisreducedwhilethecathodeoxidizes.Thedirectionofflow
isreversed.
10. Whichelectrochemicalprocess(chargingordischarging)occursviaelectrolysis?
Brieflyexplainwhatisoccurringinthisprocess.
Electrolysishappensduringcharging,electricalenergyissuppliedtomakearedox
reactionhappen.Thisleadstotheaforementionedoxidationandreduction.
11. Whenhydrogenandoxygengasarebeingcreatedforthechargingstep,bywhat
ratioaretheybeingcreated.Doesthisagreewiththestoichiometryinthebalanced
chemicalreactionfromabove?Whyorwhynot?
Itisa2:1ratioofhydrogentooxygen.Forevery2molesofhydrogenproduced,one
moleofoxygenisproduced.Itdoesagreewiththebalancedchemicalreaction.
Experiment 1: Determining a Method for Increasing Operation Time per Charge
12. Fillinyourdatabelowandanswerthefollowingquestions:
Table 3. OperationTimeformodifiedprocedure.
Modified Procedure
Time (s)
Trial 1
193s
*Class Average*
N/A
a. WhatwasyourunmodifiedprocedureruntimefromTable2? __191s______
b. Howdoesthisruntimecomparetothemodifiedprocedureruntimes from Table
3? Did the modifications have the expected effect on the run time? Why/Why
not?
It took slightlylongertofullydischarge.Themodificationssomewhathadtheexpected
effectofincreasingtheruntime,howeverwethoughtitwouldsignificantly increase the
timeratherthanjustadding2seconds.
c. Brieflydescribewhatmethodyouusedtoincreasetheruntime.
WeaddedmorefuelcellssotherewouldbemoreH2andO2gasavailable.
d. Listapotentialdrawbackofyourmethodifyouhadtoapplyitonalargerscale.
Itwouldrequiremorespacetobetakenupandbelessspaceefficient.
e. Howdidyourmethodcomparetoothergroups?Whatisanothermethodthat
alsoextendedtheruntime?
Othergroupswerealsoabletoincreasetheirruntimesfollowingasimilarprotocol.A
differentmethodthatcouldbedoneistouseacatalysttoenhancetheelectrochemical
reactionwithinthefuelcell.
Experiment 2: Define Fuel Cell Function and Efficiency
13. Fillinyourdatabelow:
Table 4. FuelCellFunctionDataTable
Trial
V
Multimete
r
Charging
Voltag
e (V)
I
Multimete
r
Charging
Current
(A)
Pc
Chargin
g Power
(W) 1
V
Multimeter
Dischargin
g Voltage
(V)
I
Multimeter
Dischargin
g Current
(A)
Pd
Dischargin
g Power
(W) 1
% Efficiency
P x100%d/ Pc
(%)2
1
1.70
1.87
3.18
0.73
0.68
0.50
16%
2
1.72
1.89
3.25
0.77
0.72
0.50
18%
ACalculation Example Shown below in Question 14 A
BCalculation Example Shown below in Question 14 B
14. Includeallworkwithunitsandsigfigsforthefollowingsamplecalculations:
DatafromTrial___1___:
A) Use thecurrent(I,inA)andvoltage(V,inV)toshowasamplecalculation
forthePower(P,inW)foroneofthechargingordischargingcycles.
(1Watt=1Volt×1Amp):
P=V∙I
B) Calculate%Efficiencyforthefuelcell.
15. Compareandcontrasttheresultsofthepowerreadingsforboththechargingand
dischargingstepsforthefollowing:
a. Whichsteptakesmoreenergy?Explainhowyouknow.
Chargingtakesmoreenergyaccordingtothetable.Thedecompositionrequires
additionalenergyinputandcontributestotheoverallhigherpowerdemandduring
charging.
b. Wasalloftheenergycreatedbythefuelcellsconvertedintoelectricalenergy?
Explain.
No,notalloftheenergycreatedbythefuelcellisconvertedintoelectricalenergy.
Whilefuelcellsareknownfortheirrelativelyhighefficiencyinconvertingchemical
energyintoelectricalenergy,theydoloseenergytofactorssuchasheatloss,
electrochemicallosses,ohmiclosses,andinefficienciesinhydrogenproduction.
c. Howdoesthepercentefficiencyforthefuelcellcarcomparetotheprospective
percentefficiencyforcommercialfuelcells?Discusspossiblereasonsforany
differencesbetweenyourresultsandcommercialfuelcells.
Tocomparethepercentefficiencyofafuelcellcarwiththeprospectivepercent
efficiencyforcommercialfuelcells,it'simportanttonotethattheefficiencyofafuelcell
systemcandependonvariousfactors,includingthetypeoffuelcell,operating
conditions,andtheoverallsystemdesign.Potentialdifferencescouldarisefromsystem
designandintegration,operatingconditions,andthefuelsourceused.
Experiment 3: Calculate Current Experimentally Using Gas Volume Rate of
Change.
16. Fillinyourdatabelow:
Table 5: Comparison of Current Measurement Techniques
Room Temperature, K: 293
Atmospheric Pressure, Atm: 0.9178
Num
ΔV (L)
Moles
gas
(mol) 3
n=PV/RT
Δt
(s)
Calculated
Charging
Current 3
(A)
Avg
Calculated
Charging
Current
(A)
Avg
Multimeter
Charging
Current
(Table 4)
(A)
%
Difference
(%)4
H2
1
.20
6.40*10^-4
377
.529
.37884
.89
78.02
H2
2
.18
6.23*10^-4
488
.388
.38332
.94
78.13
H2
3
.16
6.92*10^-4
382
.458
.38127
.79
77.89
O2
1
.20
7.21*10^-4
740
.430
.39122
.81
79.91
O2
2
.19
6.72*10^-4
634
.375
.38433
.86
81.22
O2
3
.17
6.55*10^-4
397
.387
.38348
.85
81.01
ACalculation Example Shown below in Question 17 A
BCalculation Example Shown below in Question 17 B
17. Includeallworkwithunitsandsigfigsforthefollowingsamplecalculations:
DatafromTrial__1____:
A) Use the atmospheric pressure, room temperature, and the volume of
water displaced to convert toapproximatemolesofH2(g)generatedduring
thechargingcycle.
R=__0.08206L•atm/mol•K___(IdealGasConstant)
T= (RoomTempinK) n=PV/RT__293K__
P = __0.9178atm___(atmosphericPressurefromTA)
V = ____22mL_____(fromTable2)
B) Usethestoichiometryofthebalancedhalfreaction,valuesofmolesof
electrons, and time (t, ins)tocalculatethecurrentinampsforthischarging
cycleforthefuelcell.(1A=1C/sand1molee-=96485Cofcharge).
Provideoneexamplecalculationforeachgas.
H2=(4*96485C/mol)/3600s
O2=(2*96485C/mol)/3600s
C) Calculate thepercentagedifferencebetweenthemultimetervalueandthe
calculatedchargingcurrent.
%Difference:|A +A
multi–Amol| / [(Amulti mol)/2] *100%
=|2A-1.8A|/(|2A+1.8A|/2)*100
18. Compareandcontrastthemultimetercurrentreadingvsthecalculatedcurrent
values(Table5).
a. Whatdoesyourpercentdifferencevaluemeanabouthowwellthetwomethods
ofcurrentcollectionwereinagreement?
Thehighpercentdifferencevaluesuggeststhatthereisasignificantdisagreement
betweenthetwomethodsofcurrentcollection.
b. Providetwoplausibleexplanationsforanydifferences.
i.Measurementerrorsinoneorbothofthemethodscouldleadtoahighpercent
difference.Forexample,inaccuraciesintheinstrumentsusedforcurrentcollection,
calibrationissues,orvariationsintheexperimentalconditionsmightresultin
discrepancies.
ii.Differencesintheexperimentalconditionsbetweenthetwomethodsmayleadto
variationsincurrentcollection.Factorssuchastemperature,humidity,orpressurecan
influencethebehaviorofthesystemandaffecttheresults.
Follow-up questions
19. Listtwodifferentapplicationsthatcouldbepoweredbyafuelcell.
a. Transportation-hydrogenfuelcellvehicles
b. Stationarypowergeneration-backuppowersystems
20. Listtwoadvantagesofusingfuelcellvehiclesinsteadofourcurrentfossilfuel
vehicles.
a. Zeroemissionsatthepointofuse
b. Highefficiencyandreduceddependencyonfossilfuels
