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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
Outline

• NREL’s Projects – Focus on Temperature

• xEVs – Prospects & Barriers

• Impact of Temperature on Li‐Ion Batterie

o Performanceo Lifeo Safety

• Controlling or Reducing the Impact of Tem

o Material Selectiono Cell and Module Designo Balance of System Design

• Summary
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NREL Energy Storage Proje

Supporting DOE and industry to achieve energy storage targets for 

NREL

Energy Storage

Project

NREL

Energy Storage

Project

Battery Battery Material Material Research Research and Develo

Develo

Component Testing and Characterizat(Including Safety)Component Testing and Characterizat(Including Safety)Multi‐physics Battery Modeling

(including Safety)

Multi‐physics Battery Modeling

(including Safety)

Battery Battery Life Prediction Prediction and Trade‐offBattery System Evaluation
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xEVs – 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 

Super clean cars that run on inexpensive domest

xEVs:Hybrid Plug-in ExtendBattery 
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xEVs – Barriers

• Higher marginal price of xEVs relative to conv

vehicles (mostly due to battery)

• Long pay-back times of xEVs• Low gas prices• Improvements in fuel economy of conventiona• Interest in start-stop, micro hybrid, and electric 

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 environme
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Large Format Li-Ion Batteries for 

• 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 
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• Cold temperature effects

• Battery performance (power, Energy) lower due to po

transport

• xEV acceleration and range are much more affected 

conventional vehicles

• Passenger heating needed, BEV range is reduced us

energy (higher gas emissions if engine used for PHE

• Charging is much more challenging as dendrite can g

reduce life of battery and compromise safety 

• Hot temperature effects

• Side reactions happens faster so battery degrades fa• Faster battery degradation means higher cost for rep• Passenger cooling needed, BEV range is reduce usin

energy (more pollution if engine use for PHEV and ER

• Very hot temperature effects

• Potential for thermal runaway and safety incidents

Concerns about xEV Battery Tem

High and low temps lead to battery over-sizing and increas
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High EC (5:3

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)

Cold Temperature Effects 

Disctest and

at r

M.C158

Poor Charge Acceptance
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Chemical 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 abuseperformance of the cell

Cold Temperature Effects 
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Battery power and energy are lower due to 

transport in cold temperatures

Energy and Power Lower in C

LiFe

Gra

Carbona
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• xEV acceleration and electric range are muc

cold temp than affected than conventional ve

Impact of Low Temps on xEV Perfo

http://www.transportation.anl.gov/D3/data/2012_nissan_leaf/AVTALeaftestinganalysis_Major%20summary101212.pdf

Data from Argonne National Laboratory

Advanced Powertrain Research Facility

http://news.fleetcarmacar‐range‐in‐bitter‐cold

2012 Nissan Leaf BEV
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Impact of Temp on Cell Heat Gen

Large-Cell Calorimetry• Profiles: USABC & US06 

cycles, const. current

• Lower the temp, higher heat 

generation due to higher Resistance

Heat Generation Rate (W)

RMS Current (A)
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Dendrite Growth in Cold Tempera

 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 life of battery and compromise safety 

Li-Ion battery modelingS. Santhanagopalan (N
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Poor cycle life due to loss of cyclable lithium and active material at elevated temperatures.

High Temperature Effects 

Increased rate of side‐reactions results in loss of cyclable lithium of attrition of active material at higher temperatures: the solid lin

model results and the red circles are experimental data

Santhanagopalan et al., JES 155(4), p. A345 (2008)
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• 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 surface

High Temperature Effects 

Cathode

Anode

Half-cell Potentials from cells subjected ttemperatures: Side reactions happen fassurface with increase in the temperature build-up of the resistance at the electrode Smart et al., JES V. 152(6), p. A1096 (2005)
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• Models have correlated the relation between capacity & • Faster battery degradation means higher cost for repla

Higher LIB Degradation at Higher Tem
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• Passenger heating needed, BEV range is reduced using b

(more pollution if engine use for PHEV and EREV)

• Passenger cooling needed, BEV range is reduced using b

(more pollution if engine use for PHEV and EREV)

• NREL analysis has shown that climate-control system load

increase fuel consumption in PHEVs by as much as 61% decrease electric range by up to 35% in EVs. 

Comfort Heat/Cooling Reduces xEV 
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If Heating‐Rate

exceedsDissipation‐Rate

Thermal Runaway of LIB and Safety E

T

Leak

Smoke

Gas Ven

Internal Short Circuit

Lithium Plating

Causing or EnergizingInternal Events or

Exothermic Reactions

DecompositionsElectrochemicalReaction

Electrode‐ElectrolyteReactions

External Heating

Over‐Charging

High Current Charging

Crush

Object penetration

ExternalAbuse Conditions

External Short

Over‐Discharging

Ra

Th

Flammable Electrolyte

If Heating‐

Rate exceeds

Dissipation‐Rate

(The flammability of the vented electrolyte is a significant unresolved s
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Thermal Runaway in Li-Ion C

1. An external source of h

temperature of the celTemperature

2. If this heat is not dissip

temperature will contin

exothermic reactions a

Acceleration, which is 

more rapid and acceler

3. Additional heating causes the cell to

enter Runaway, in which the high‐

rate cathode and/or anodereactions 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.pdf

From C. Schafer Battery 
Battery Temperature in xEV

• Temperature has a significant impact on life, perfo

safety, and thus cost of LIBs and eventually afforda

Power

Limits

15°C 35°C

discharge

charge

Rated

Power

Degradation Sluggish Electrochemistry

Power

Limits

15°C 35°C

discharge

charge

Rated

Power

Degradation Sluggish Electrochemistry

Dictatespower capability through

cold cranking

Also limitsthe electric driving range

Dictatesthe siz

on the power 

fade 

Limit

reduced 

de

Kandler Smith, NREL Milestone Report, 200

Desired

Operating

Temperature
Addressing Temperature Issues

• Material Selection

• Cell and Module Design

• Balance of the System

Power

Limits

15°C 35°C

discharge

charge

Rated

Power

T

Degradation Sluggish Electrochemistry

Power

Limits

15°C 35°C

discharge

charge

Rated

Power

T

Degradation Sluggish Electrochemistry

Dictatespower capability through

cold cranking

Also limitsthe electric driving range

Dictatesthe size depending

on the power and energy

fade rate

Limitingpower to

reduced T increase an

degradation

Kandler Smith, NREL Milestone Report, 2008

Desired

Operating

Temperature
Material Selection – Performance 

• 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 Treatments

o Improve stabilityo Improve conductivityo Coatingo Atomic or molecular layer depositions
Using Materials to Address Temperatu

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 Me

have been shown 

operation at temp

‐60oC.

Smart et al., JES 1

• Performance and Life
Using Materials to Address Temperatu

• Safety

o Develop non‐flammable electrolytes (Ioo Adding fire retardants additiveso Develop high energy cathodes that do n

oxygen

o Develop coatings for cathodes and anodo Develop artificial SEI layer for anodeso Develop new separators that maintain i

and little shrinkage at high temperature

o Design and placement of heat resistanc
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Cell and Pack Designs can Alleviat

Effects 

• Cell design for more uniform heat distribution
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Electric Potential Distribution

across the module

Cooling Channe

Cell & Module Design to Addres

Temperature Issues 
Use Balance of System to Addr

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 life
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Standby Cooling in Hot Clim

28

• 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 

How mon ther

PHEV 1
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Summary

• Lithium-ion battery (LIB) technology is expect

the energy storage of choice for electric drive (xEVs) in the coming years

• Temperature has significant impact on Li-Ion 

– Performance  lower range– Life  higher cost

– Safety  lower market acceptance 

• Controlling or reducing the adverse impact of 

temperature could be done through

– Material Selection (thermal stability and electrolyte – Cell and Module Design– Balance of System Design (thermal management, 

standby and pre-conditioning)

• NREL has developed tools and models to inv

impact of the extreme temperatures on LIB an
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Acknowledgments

• Support provided by the DOE Vehicle Technolo

Program

– Dave Howell, Hybrid and Electric Systems Team Lea– Brian Cunningham, Energy Storage Technology Ma

• Support from NREL Energy Storage Team 

– Matt Keyser– Kandler Smith– John Ireland– Dirk Long

nrel.gov/vehiclesandfuels/energy

Contact Informatio

Ahmad Pesaran

ahmad.pesaran@nre

303‐275‐4441