Markel, T.

Pesaran, A.

UNT Digital Library

Battery Requirements and Cost-Benefit Analysis for Plug-In Hybrid Vehicles Ahmad PesaranTony MarkelNational Renewable Energy LaboratoryGolden, CO, USAahmad_pesaran@nrel.gov, Tel: 303 275-4441THE 24th INTERNATIONAL BATTERY SEMINAR & EXHIBITMarch 19 - 22, 2007Fort Lauderdale, FloridaWith funding from FreedomCAR and Vehicle Technologies ProgramOffice of Energy Efficiency and Renewable Energy U.S. Department of Energy NREL/PR-540-42082 2Outline• Why Plug-In Hybrids?• What is a Plug-In Hybrid?• Definitions and Terminologies• Current Plug-in Hybrid Conversions• Battery Requirements• Analysis – Benefits and Costs• Summary3Why are Alternative Fuel and Efficient Vehicles Needed? • Petroleum consumption has steadily increasedwhile domestic production has continued to decline• Energy security and oil independence are major concerns in US• World oil production will likely peak within the next 5-15 years• Recent increase in gasoline price is an indicator of growing tension between supply and demand• Greenhouse gas emission and global warmingconcerns4Why are Plug-In Hybrids Getting a lot of Attention?• Most hybrid vehicles still consume petroleum.• Alternative fuel vehicles such as E85 are available, but fuel and required infrastructure are not ready.• Mass production of hydrogen fuel cell vehicles is not likely in the next 15 years. • Electric vehicles are not likely to be mass produced in the next 20 years due to battery cost, charging time and fast charging infrastructure requirements.• Plug in hybrids offer potential for both energy efficiency and use of domestic energy (electricity) without paradigm shift in a new fueling infrastructure.• A majority of US drivers travel fewer than 40 miles a day, so a vehicle with short EV range and long petroleum range is very attractive.• The President’s State of Union Address in 2006 & 20075Plug-in Hybrid Stakeholder ObjectivesState Gov.Reduced air pollution;Use renewable energyUS Gov./DOEReduced petroleum use;Use alternative energyAuto ManufacturersSell carsElectric UtilitiesSell electricityBattery ManufacturersSell batteriesConsumersDrive affordablefunctional, fun, and feel good cars Security advocates, Environmentalists, ConsortiumsConversion companies, Component suppliers 6What is a Plug-In Hybrid Electric Vehicle An HEV with an energy storage system that could be charged with off-board electricityELECTRIC ACCESSORIESADVANCED ENGINEENGINE IDLE-OFFENGINE DOWNSIZINGREGENERATIVE BRAKINGBATTERY RECHARGEELECTRICITYPETROLEUMAND/ORFuel Flexibility7Some PHEV DefinitionsCharge-Depleting (CD) HEV Mode:  Vehicle operation on the electric drive, engine subsystem or both with a net decrease in battery state-of-charge. Charge-Sustaining (CS) HEV Mode:  Vehicle operation on the electric drive, engine subsystem or both at ‘relatively constant’ battery state-of-charge (i.e. within a narrow range).All-Electric Range (AER):  After a full recharge, the total miles driven electrically (engine-off) before the engine turns on for the first time.Charge-Depleting Range (CDR):  After a full recharge, the total miles driven before the vehicle reaches charge-sustaining mode.PHEV20:  A PHEV with useable energy storage equivalent to 20 miles of driving energy on a reference driving cycle.  A PHEV20 can displace petroleum energy equivalent to 20 miles of driving on the reference cycle with off-board electricity.NOTE: PHEV20 does not imply that the vehicle will achieve 20 miles of AER or CDR on the  reference cycle nor any other driving cycle.  Operating characteristics also depend on the power ratings of components, the powertrain control strategy and the nature of the driving cycle.8Operating Strategy OptionsAll-Electric or Blended/Hybrid• Engine turns on when power exceeds battery power capability• Engine only provides load that exceeds battery power capability• Engine is off during the electric range• Engine turns on when battery reaches low state of charge• Requires high power battery and motorCharge Depleting ElectricCharge Depleting Hybrid (Blended)9How Do PHEVs Reduce Petroleum Consumption?DistanceConsumptionConventional VehicleHybrid Vehicle~10-35%Charge-Depleting Mode Charge-Sustaining ModePlug-In Hybrid VehiclePHEV BenefitsEfficiency in Charge-Sustaining ModePetroleum Displacement in Charge-Depleting ModeConsumption Benefits of PHEV Technology Tied to Usage Pattern~35-50%~10-35%~50-80%10Some of PHEV Prototypes EnergyCS Plug-In Prius Hymotion Escape PHEVAC Propulsion Jetta PHEVAFS Trinity Extreme Hybrid™Renault Kangoo Elect’roadDaimlerChrysler Sprinter Van PHEV11Batteries in Current PHEVsJohnson Controls / SAFTValence TechnologyKokam A123 SystemsElectro Energy Inc.NiMHCo/Ni basedLi-IonIron phosphate based Li-IonJohnson Controls / Varta12Battery Usage in EVs, HEVs, and PHEVs*Battery capacity for a midsize carCS: Charge SustainingCD: Charge DepletingUncharged capacityCharged and used (CD)Charged capacity, not usedCharged and used (CD)Used frequently in CSUsed sometimes in CSTotal BatteryCapacity*Charged, not used1-2 kWh6-12 kWh30-40 kWhCharged, not used13400050%70%Battery Cycle Life Depends on State of Charge Swing • PHEV battery likely to deep-cycle each day driven:  15 yrs equates to 4000-5000 deep cycles• Also need to consider combination of high and low frequency cyclingSource: Christian Rosenkranz (Johnson Controls) at EVS 20, Long Beach, CA, November 15-19, 2003Need to obtain similar data for state-of-the-art batteries14Battery Sizing Depends on:EV range, vehicle (mass, aerodynamic, etc.), drive cycle, strategy kWh/mi(from simulation)SOC windowEqui EV rangekWmotor(from simulation)Performance constraintskWh usablekWh totalP/EkWengineDOHBenefit of plugging-inBenefit of hybridizationTotal MPG Benefitmass compoundingDOH = degree of hybridizationSource: Tony Markel and Andrew Simpson, Milestone Report, National Renewable Energy Laboratory, Golden, CO, September 2005. 15Example of Battery Requirements for Plug-in Hybrid Vehicles1. These categories are similar to the ones proposed for USABC charge-depleting electric vehicles and FreedomCAR charge-depleting power-assist HEVs2.       Typical numbers, final USABC numbers could be found in http://www.uscar.org/commands/files_download.php?files_id=1182116KEY BENEFITSConsumer:• Lower “fuel” costs• Fewer fill-ups• Home recharging convenience• Fuel flexibilityNation:• Less petroleum use• Less greenhouse and regulated emissions• Energy diversity/securityPHEV Key Benefits and ChallengesCost-Benefit AnalysisKEY CHALLENGES• Energy Storage/Battery – Cost– Life • Shallow and deep cycles• Calendar – Safety– Packaging– Thermal Management• Power Electronics• Vehicle cost17Predicted fuel economy and operating costs for midsize sedan11) Assumes 15,000 miles annually, gasoline price of $2.40 per gallon, electricity price of 9c/kWh2) Note that average US household consumes 10,700 kWh of electricity each year3) Using 110V, 20A household outletPlug-In Hybrid Fuel EconomyVehicle Type Gasoline Fuel EconomyElectricity UseAnnual Energy UseAnnual Energy CostRecharge Time3Conventional 27 mpg --- 564 gal. $1360 ---Hybrid-Electric 36 mpg --- 416 gal. $1000 ---Plug-In Hybrid20mi range51 mpg 0.09 kWh/mi 297 gal. and 1394 kWh2$716 + $125 < 4 hrsPlug-In Hybrid40mi range69 mpg 0.16 kWh/mi 218 gal. and 2342 kWh2$525 + $211 < 8 hrs18Powertrain Costs Comparison – Long TermUDDS AER PHEVsFrom A. Simpson and T. Markel, 22nd Electric Vehicle Symposium, Yokohoma, Japan, October 200619Long-term scenarioLI-ION BATTERIES$3.00/gal. $0.09¢/kWh (2005 average, not off-peak)Payback time of PHEVs Relative to HEVs depends on the initial battery cost and fuel cost Maintenance costs not included, no discount rate appliedFrom A. Simpson and T. Markel, 22nd Electric Vehicle Symposium, Yokohoma, Japan, October 200620Long-term scenarioLI-ION BATTERIESBoth Higher Gas Prices and Lower Battery Costs Required for PHEV to Payback Relative to HEVMaintenance costs not included, no discount rate applied$5.00/gal. (future?)$0.09¢/kWh (2005 average, not off-peak)From A. Simpson and T. Markel, 22nd Electric Vehicle Symposium, Yokohoma, Japan, October 2006Incentives or other tax breaks may be needed21Concerns with Battery Packaging and Management 22Concluding Remarks• PHEVs could displace petroleum consumption with domestic and renewable electricity.• Batteries with low power to energy ratios are needed for PHEVs.• Widening of the battery’s usable SOC window while maintaining life will be critical for reducing system cost and volume, but could decrease the life.• A blended operating strategy as opposed to an all electric range focused strategy may provide some benefit in reducing cost and volume while maintaining petroleum consumption benefits.• Battery requirements for PHEVs are demanding: low cost, wide T operation, wide SOC operation, both shallow and deep cycles.• PHEVs make economic sense with lower battery cost and higher gasoline prices, otherwise other incentives or tax credits needed.• The key barriers to commercialization of PHEVs are battery life, packaging, safety, and cost.

Battery Requirements and Cost-Benefit Analysis for Plug-In Hybrid Vehicles

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Battery Requirements and Cost-Benefit Analysis for Plug-In Hybrid Vehicles

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