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.

An Update on the Battery Projects at NREL

Shriram Santhanagopalan

Ahmad Pesaran

Funding provided by Energy Storage R&D, 

Vehicle Technologies, U.S. Department of 

Energy (David Howell)

Battery Power 2010

October 19-20, Dallas, Texas

NREL/PR-5400-49796
Innovation for Our Energy Future

The Team

Terry Penney Anne Dillon 

Ahmad Pesaran Chunmei Ban

Matt Keyser Kyu Jin Lee

Gi-Heon Kim Dirk Long

Kandler Smith Yoon Seok Jung

Jeremy Neubauer John Ireland

Jeff Gonder Michael O’Keefe 

Aaron Brooker Tony Markel

Larry Chaney Robert Tenant

Dave Howell Tien Duong

Steve Gougen Brian Cunningham

Acknowledgements

Funding from The Department of Energy

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Innovation for Our Energy Future

NREL Energy Storage Project Structure

3

Energy Storage Task 

Materials 

Development

Component 

Modeling

Component 

Testing

Life Trade-off 

Studies

System 

Evaluation

Special Projects

IEA HEV-IA CAEBAT 

Business 

Development
Innovation for Our Energy Future

Cost 

NREL Approach to Vehicle Battery Optimization

Life

Source: INL, 

LBNL

Source: 

VARTA

Performance

Safety

4

Focused on Leveraging Expertise 

in Battery Thermal Management

Robust design of batteries to meet the industry’s requirements at minimum cost
Innovation for Our Energy Future

Lab Upgrades

Completed System with Heating/Cooling Unit Test Chamber in Isothermal Bath

New Calorimeter for Large, Liquid-Cooled HEV & PHEV Modules

Controlled Environment Chambers and Pack Testers

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New Environmental Chambers Battery Pack Testers Photo: Dirk Long

Photo: Dirk Long

Photo: Matt KeyserPhoto: Matt Keyser
Innovation for Our Energy Future

The model predicted lower and more uniform temperature distribution in 2004 

module. 

The E-T Model – A Tool To Design Batteries with 

Better Thermal Performance

Response at the end of 100 A constant current discharge (3 min)

2001 Module 2004 Module

Model

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Innovation for Our Energy Future

Materials Work

7

MoO3 nanoparticles produced with economical hot-wire chemical vapor deposition (HWCVD). Atomic layer 

deposition (ALD) coatings enable durable high-rate capability cycling.

L.A. Riley, A.S. Cavenagh, S.M. George, Y. S. Jung, Y. Yan, S-H. Lee, and A.C. Dillon - ChemPhysChem (available online)

C. Ban, Z. Wu, D. T. Gillaspie, L. Chen, Y. Yan, J. L. Blackburn, and A.C. Dillon - Advanced Materials (available online)

NREL Demonstrated Two Methods to Improve Rate 

Iron oxide made with inexpensive hydrothermal process. 5 wt.% single wall carbon nanotubes (SWNTs) 

enable binder-free electrode with durable high-rate capability cycling.

TEM of as-synthesized product Fe3O4/ SWNT electrode

Iron Precursor

Buffer Solution

Solvent

Annealing

w/ SWNT
Innovation for Our Energy Future

NREL’s Safety Models

0 10 20 30 40 50 60 2.8

3

3.2

3.4

3.6

3.8

4

time

cell voltage [V]

T

Q

30 sec

T

Q

40 sec

T

Q

50 sec

T

Q

60 sec

 

 

T

Q

20 sec

Stress (MPa)

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Innovation for Our Energy Future

NREL Life Model 

NCA datasets fit with empirical, yet physically justifiable formulas

Resistance

Growth

Relative

Capacity

Li-ion NCA chemistry

• Data shown above: J.C. Hall, IECEC, 2006.

• Not shown: Model also fit to DOE/TLVT, 

Southern CA Edison & NASA data

Resistance 

Growth (m

Ω)

Qactive = c0 + c1 N

R = a1 t

1/2 + a2 N

Calendar fade

• SEI growth (partially 

suppressed by cycling)

• Loss of cyclable lithium 

• a1(∆DOD,T,V)

Q = min ( QLi , Qactive )

QLi = b0 + b1 t

1/2

*K. Smith, T. Markel, A. Pesaran. “PHEV Battery Trade-off Study and Standby Thermal Control,” 26th

International Battery Seminar & Exhibit, Fort Lauderdale, FL, March 2009.

Cycling fade

• Active material structure 

degradation and 

mechanical fracture

• a2(∆DOD,T,V)

Relative Capacity (%)

Time (years)

Time (days)

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Predictive model that considers effects of realworld storage and cycling scenarios 
Innovation for Our Energy Future

Model Comparison: PHEV Accelerated Cycling

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Resistance Growth:

• Linear trend of data 

indicates cycling 

dominates resistance 

growth rather than SEI 

growth with square-root-oftime

• Baseline life model 

requires some adjustment:

• SEI-resistance-growth rate 

constant, a1,ref, is reduced as 

required to match Belt/INL’s Saft

HP12LC HEV data

• Cycling-resistance-growth rate 

constant, a2,ref, is also reduced

Data: Gaillac/SCE (2009)

– 3.75 years CD/CS cycle testing, ~4 cycles/day at ∆DOD = 0.75, T = 25 C

Rel. Resistance, 18s at 50% DOD
Innovation for Our Energy Future

Phoenix

49oC max, 27 C avg

Houston

42oC max, 23 C avg

Minneapolis

41oC max, 10 C avg

Ambient Effects 

+ Solar Gain 

(Vehicle/Battery 

Thermal Interactions)

Impact of Temperature on Battery in a Parked Car 

(Battery T = Ambient T + Solar Gain)

• The same as previous slide (PHEV10, NCA chemistry, and TYM weather) 

• Developed a vehicle-battery-ambient model to predict the battery temperature

• Results show significant fade due to the ambient temperature and solar gain

0oC

10oC

20oC

30oC

40oC

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Innovation for Our Energy Future

Cost Versus Power/Energy Ratio of Cell Design

Example: PHEV20 battery sized for 10 years life with 1 cycle/day

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– Battery designer must 

select from available cell 

designs (e.g., P/E = 5, 10, 

15 kW/kWh)

• Excess Energy = unused 

active material (very 

expensive)

• Excess Power

– Allows deeper ∆DOD 

(most efficient use of 

active materials)

– Reduces heat load

– Pack cost rises $180 for 

each 10 C additional 

temperature exposure

• Thermal management

• Ambient temperature

Excess

Energy

Excess

Power
13 Innovation for Our Energy Future

Battery Second-Use Strategies

Manufactured & Installed 

in Automobile

Employed in Automotive 

Application

Refurbished & Installed in 

Second Use Application

Employed in Second Use 

Application

Recycled

Scenario 1: $15,333

Scenario 2: $16,479 

Early retirement sounds good here... 

but under these assumptions the 

battery is most cost-effective when 

never installed in an automobile! 

Scenario 3: 

$8,030 Looks really bad, but 

remember the initial battery 

cost is assumed to be much 

lower!
Innovation for Our Energy Future

DOE-sponsored projects

Industry-sponsored projects

Strong Partnership with Universities and Industry

BOLDER

Technologies

University of

Toledo

Compact Power

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Innovation for Our Energy Future

Summary

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• NREL collaborates with industry, universities, and other national labs as part 

of the DOE integrated Energy Storage Program to develop advanced 

batteries for vehicle applications.

• Our efforts are focused in the following areas:

1. Thermal characterization and analysis

2. Evaluation of thermal abuse tolerance via modeling and experimental 

analysis

3. Implications on battery life and cost

• Our activities support DOE goals, FreedomCAR targets, the USABC Tech 

Team, and battery developers.

• We develop tools to support the industry both through one-on-one 

collaborations and by dissemination of information in the form of 

presentations in conferences and journal publications. 

www.nrel.gov/vehiclesandfuels/energystorage/publications.html