This presentation discusses the effects of temperature on large format lithium-ion batteries in electric drive vehicles

Kim, G. H.

Pesaran, A.

Santhanagopalan, S.

UNT Digital Library

NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC. Addressing the Impact of Temperature Extremes on Large Format Li-Ion Batteries for Vehicle Applications Ahmad Pesaran, Ph.D. Shriram Santhanagopalan, Gi-Heon Kim National Renewable Energy Laboratory Golden, Colorado 30TH INTERNATIONAL BATTERY SEMINAR Ft. Lauderdale, Florida March 11-14, 2013 NREL/PR-5400-58145 2Outline• NREL’s Projects – Focus on Temperature• xEVs – Prospects & Barriers • Impact of Temperature on Li‐Ion Batterieso Performanceo Lifeo Safety• Controlling or Reducing the Impact of Temperatureo Material Selectiono Cell and Module Designo Balance of System Design• SummaryNATIONAL RENEWABLE ENERGY LABORATORYNREL Energy Storage Projects3Supporting DOE and industry to achieve energy storage targets for electrified vehiclesNRELEnergy Storage ProjectBattery Material Research and Development Component Testing and Characterization (Including Safety)Multi‐physics Battery Modeling(including Safety)Battery Life Prediction and Trade‐offBattery System EvaluationWorking on temperature dependent issues NATIONAL RENEWABLE ENERGY LABORATORYxEVs – Prospects• Acceptance of hybrid vehicles by consumers• Economic impact of high prices of oil• Higher prices of gasoline and its volatility • Oil peak and gap in production• Importing oil from unstable countries • Energy security • Political pressure to use domestic fuel• Environmental impact of using fossil fuel• Greenhouse gases• Climate change• Increased interest of public in green and renewable technologies• Regulation and policies – Upcoming Fuel Economy Standards 4Super clean cars that run on inexpensive domestics electricity xEVs:Hybrid Electric VehiclesPlug-in HEVsExtended Range EVsBattery Electric VehiclesNATIONAL RENEWABLE ENERGY LABORATORYxEVs – Barriers5• Higher marginal price of xEVs relative to conventional vehicles (mostly due to battery)• Long pay-back times of xEVs• Low gas prices• Improvements in fuel economy of conventional vehicles• Interest in start-stop, micro hybrid, and electric assist vehicles• Battery life; Cost for replacement• Safety of lithium-ion powered xEVs• Limited driving range of BEVs • Charge time for PHEVs, EREVs, and BEVs• Accessibility to large number of charge points• Lower performance at cold and hot environmentsNATIONAL RENEWABLE ENERGY LABORATORYLarge Format Li-Ion Batteries for xEVs6• Lithium-ion battery  technology is expected to be the energy storage choice for (xEVs) in the coming years• Better (energy & power) performance than other existing technologies• Trends toward large format cells • Higher volume &weight efficiencies and packaging• Lower # of connections and components• Lower system cost NATIONAL RENEWABLE ENERGY LABORATORY• Cold temperature effects• Battery performance (power, Energy) lower due to poor ion transport• xEV acceleration and range are much more affected than conventional vehicles• Passenger heating needed, BEV range is reduced using battery energy (higher gas emissions if engine used for PHEV and EREV)• Charging is much more challenging as dendrite can grow and reduce life of battery and compromise safety • Hot temperature effects• Side reactions happens faster so battery degrades faster• Faster battery degradation means higher cost for replacement• Passenger cooling needed, BEV range is reduce using battery energy (more pollution if engine use for PHEV and EREV)• Very hot temperature effects• Potential for thermal runaway and safety incidents7Concerns about xEV Battery Temperature High and low temps lead to battery over-sizing and increased costNATIONAL RENEWABLE ENERGY LABORATORYHigh EC (5:3:2 EC:DMC:EMC)Physical Effects:– Viscosity changes in the electrolyte lead to sluggish ion transport– Polymeric components within the cell tend to become brittle (e.g., active material within the electrodes tends to fall apart due to binder failure)8Cold Temperature Effects - 1 Discharge curves of MCMB‐NCO Li‐ion test cells with electrolytes, at 25 mAand ‐20oC, following charge at 70 mAat room temperature and –20oC.M.C. Smart and B.V. Ratnakumar, JES 158(4) p. A379‐A389 (2011)Poor Charge AcceptanceNATIONAL RENEWABLE ENERGY LABORATORYChemical Effects:• Type of additives used to improve low temperature performance introduce changes to the SEI properties:• compact, barrier-type, protective films are formed in solutions based on alkyl carbonates• bulky, porous, and less protective films are formed with DME additives  (Smart et al., JES 146(11) p. 3963 (1999))• Resistance build-up across the SEI influences the abuse-performance of the cell9Cold Temperature Effects - 2NATIONAL RENEWABLE ENERGY LABORATORYBattery power and energy are lower due to poor ion transport in cold temperatures10Energy and Power Lower in Cold LiFePO4 GraphiteCarbonates/LiPF6NATIONAL RENEWABLE ENERGY LABORATORY• xEV acceleration and electric range are much more in cold temp than affected than conventional vehicles11Impact of Low Temps on xEV Performance http://www.transportation.anl.gov/D3/data/2012_nissan_leaf/AVTALeaftestinganalysis_Major%20summary101212.pdfData from Argonne National LaboratoryAdvanced Powertrain Research Facilityhttp://news.fleetcarma.com/2013/01/31/electric‐car‐range‐in‐bitter‐cold/#.UQq5m_IwCVo2012 Nissan Leaf BEVNATIONAL RENEWABLE ENERGY LABORATORYImpact of Temp on Cell Heat Generation  12Large-Cell Calorimetry• Profiles: USABC & US06 cycles, const. current• Lower the temp, higher heat generation due to higher ResistanceHeat Generation Rate (W)RMS Current (A)NATIONAL RENEWABLE ENERGY LABORATORYDendrite Growth in Cold Temperatures Dendrite growth progressively worse with increase in the reacting surface area.=>  The plating reaction is accelerated by a factor of almost 10, for the worst case presented, at -20 oC.Reaction rates for a given ratio of the areas, increasingly become larger with temperature: =>  Limitations from the electrolyte are more significant than the surface effects at low temperatures (esp. below -5 oC).For the worst case, when the area of the reacting surface is double that of the reference case, the reaction rate tapers off between -5 and -20 oC despite the high over-potential=>  Bulk limitations result in non-availability of lithium at the surface.Charging is much more challenging as dendrite can grow and reduce life of battery and compromise safety Li-Ion battery modeling,     S. Santhanagopalan (NREL)NATIONAL RENEWABLE ENERGY LABORATORYPoor cycle life due to loss of cyclable lithium and active material at elevated temperatures.14High Temperature Effects - 1Increased rate of side‐reactions results in loss of cyclable lithium and higher rate of attrition of active material at higher temperatures:  the solid lines are the model results and the red circles are experimental dataSanthanagopalan et al., JES 155(4), p. A345 (2008)NATIONAL RENEWABLE ENERGY LABORATORY• Faster Degradation• Side reactions happen faster on the electrode surface (esp. anode) with increase in the temperature • Resulting in faster build-up of the resistance at the electrode surface15High Temperature Effects - 2CathodeAnodeHalf-cell Potentials from cells subjected to aging at different temperatures:  Side reactions happen faster on the electrode surface with increase in the temperature – resulting in faster build-up of the resistance at the electrode surfaceSmart et al., JES V. 152(6), p. A1096 (2005)NATIONAL RENEWABLE ENERGY LABORATORY• Models have correlated the relation between capacity & temperature • Faster battery degradation means higher cost for replacement16Higher LIB Degradation at Higher TemperaturesNATIONAL RENEWABLE ENERGY LABORATORY• Passenger heating needed, BEV range is reduced using battery energy (more pollution if engine use for PHEV and EREV)• Passenger cooling needed, BEV range is reduced using battery energy (more pollution if engine use for PHEV and EREV)• NREL analysis has shown that climate-control system loads can increase fuel consumption in PHEVs by as much as 61% and can decrease electric range by up to 35% in EVs. 17Comfort Heat/Cooling Reduces xEV RangeNATIONAL RENEWABLE ENERGY LABORATORYIf Heating‐Rate exceeds Dissipation‐RateThermal Runaway of LIB and Safety EventsThermal RunawayLeakSmokeGas VentingInternal Short CircuitLithium PlatingCausing or Energizing Internal Events or Exothermic ReactionsDecompositionsElectrochemical ReactionElectrode‐ElectrolyteReactionsExternal HeatingOver‐ChargingHigh Current ChargingCrushObject penetrationExternal Abuse ConditionsExternal ShortOver‐DischargingRapid DisassemblyFlamesThermal Runaway18Flammable ElectrolyteIf Heating‐Rate exceeds Dissipation‐Rate(The flammability of the vented electrolyte is a significant unresolved safety issue for LIBs.)NATIONAL RENEWABLE ENERGY LABORATORY 19Thermal Runaway in Li-Ion Cells1. An external source of heat raises the temperature of the cell to the Onset Temperature2. If this heat is not dissipated, the temperature will continue to rise due to exothermic reactions and the cell enters Acceleration, which is characterized by more rapid and accelerating heat release. 3. Additional heating causes the cell to enter Runaway, in which the high‐rate cathode and/or anode reactions cause the temperature to rise rapidly (thermal runaway) and flame or explosion may follow. Description of stages from Dan Doughty : http://www.nrel.gov/docs/fy13osti/54404.pdfFrom C. Schafer  Battery Safety201220Battery Temperature in xEVs• Temperature has a significant impact on life, performance, safety, and thus cost of LIBs and eventually affordability of XEVsPowerLimits15°C 35°CdischargechargeRatedPowerTDegradationSluggishElectrochemistryDictates power capability through cold crankingAlso limits the electric driving rangeDictates the size depending on the power and energy fade rateLimiting power to reduced T increase and degradation Kandler  Smith, NREL Milestone Report, 2008Desired Operating  Temperature21Addressing Temperature Issues • Material Selection• Cell and Module Design  • Balance of the System PowerLimits15°C 35°CdischargechargeRatedPowerTDegradationSluggishElectrochemistryDictates power capability through cold crankingAlso limits the electric driving rangeDictates the size depending on the power and energy fade rateLimiting power to reduced T increase and degradation Kandler  Smith, NREL Milestone Report, 2008Desired Operating  Temperature22Material Selection – Performance & Life• Choice of cathode• Choice of anode• Choice of separator  • Choice of Electrolytes o Stable at high Ts (ionic liquids?)o Good conductivity and low viscosity at low Ts• Surface morphology• Binders• Additives and Surface Treatmentso Improve stabilityo Improve conductivity o Coating o Atomic or molecular layer depositions23Using Materials to Address Temperature Issues SEM micrographs showing the surface morphology of MCMB anode structures after testing in electrolyte with EC/DMC ratios of a) 30/70 and b) 70/30:  higher EC content reduces degradation at elevated temperatures.Smart et al., JES 152(6), p. A1096 (2005) Additives like Methyl Propionate have been shown to enable cell operation at temperatures as low as ‐60oC.Smart et al., JES 157(12), p. 1361 (2010)• Performance and Life24Using Materials to Address Temperature Issues • Safetyo Develop non‐flammable electrolytes (Ionic liquids?)o Adding fire retardants additiveso Develop high energy cathodes that do not generate oxygen o Develop coatings for cathodes and anodeso Develop artificial SEI layer for anodeso Develop new separators that maintain integrality and little shrinkage at high temperatures. o Design and placement of  heat resistance layers NATIONAL RENEWABLE ENERGY LABORATORYCell and Pack Designs can Alleviate Temp Effects 25• Cell design for more uniform heat distributionNATIONAL RENEWABLE ENERGY LABORATORY 26Electric Potential Distribution across the moduleCooling Channel TemperatureCell & Module Design to Address Temperature Issues 27Use Balance of System to Address Temperature Issues • Battery Thermal Management• Heating • Cooling• Standby or pre-conditioning cooling and heating  • Advanced Sensing• Electrical Battery Management System and Control• Balancing and equalization• Advanced controls while maximizing range and lifeNATIONAL RENEWABLE ENERGY LABORATORYStandby Cooling in Hot Climates28• Battery life can greatly benefit from cooling the battery during standby, i.e. while vehicle is parked & plugged in to the grid• Refrigeration cooling systems with some insulation particularly compelling• Slower battery degradation rate enables smaller, lower cost battery ($300‐$400 savings)Battery sized for 15 years life in Phoenix, AZ, charged nightly.How much is it worth to spend on thermal control (parked too)?PHEV 10 PHEV 20 PHEV 40NATIONAL RENEWABLE ENERGY LABORATORYSummary29• Lithium-ion battery (LIB) technology is expected to be the energy storage of choice for electric drive vehicles (xEVs) in the coming years• Temperature has significant impact on Li-Ion batteries– Performance  lower range– Life  higher cost– Safety  lower market acceptance • Controlling or reducing the adverse impact of extreme temperature could be done through– Material Selection (thermal stability and electrolyte critical) – Cell and Module Design– Balance of System Design (thermal management, BMS, standby and pre-conditioning)• NREL has developed tools and models to investigate impact of the extreme temperatures on LIB and xEVsNATIONAL RENEWABLE ENERGY LABORATORYAcknowledgments• Support provided by the DOE Vehicle Technologies Program– Dave Howell, Hybrid and Electric Systems Team Lead– Brian Cunningham, Energy Storage Technology Manager• Support from NREL Energy Storage Team – Matt Keyser– Kandler Smith– John Ireland– Dirk Longnrel.gov/vehiclesandfuels/energystorageContact Information:Ahmad Pesaranahmad.pesaran@nrel.gov303‐275‐4441

Addressing the Impact of Temperature Extremes on Large Format Li-Ion Batteries for Vehicle Applications

Abstract

Similar works

Full text

Available Versions

UNT Digital Library