The project will begin with a comprehensive technical and economic analysis addressing all aspects of a battery’s lifecycle in search of the best second-use strategies, followed by a comprehensive test program to verify findings, particularly battery lifetimes. For the field test, researchers will deploy aged EV batteries at the University of California (UC), San Diego’s campus-wide electric power grid. The results of the study will: Provide validated tools and data on battery life to industry for battery reuse Recommendations for EV battery design and manufacturing practices Identify the necessary regulatory changes to encourage secondary battery use Assess the economic benefit of second uses

1. PHEV/EV Li-Ion Battery
Second-Use Project
Jeremy Neubauer
Ahmad Pesaran
April 2010
NREL/PR-540-48018
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.

2. NREL: News - NREL Team Investigates Secondary Uses for Electric Drive Vehicle Batteries
More Search Options
Site Map
NREL Newsroom Home
Printable Version
Feature News
News Releases News Release NR-1411
Science & Technology News
Events
NREL Team Investigates Secondary Uses for Electric Drive Vehicle
Research Support Facility Batteries
Construction Update
April 5, 2011
The U.S. Department of Energy’s (DOE) National Renewable Energy Laboratory (NREL), industry and
academia are teaming to give batteries from electric drive vehicles (EV) a “second life.” NREL’s partner is an
industry-academia team led by the California Center for Sustainable Energy (CCSE).
Possible secondary uses for lithium ion (Li-ion) batteries include residential and commercial electric power
management, power grid stabilization to help provide reliable electricity to users, and renewable energy
system firming — which in this case involves using batteries to make power provided to the grid by variable
resources such as wind and solar energy more useable. To date, no one has comprehensively studied the
feasibility, durability, and value of Li-ion batteries for second-use applications.
The project will begin with a comprehensive technical and economic analysis addressing all aspects of a
battery’s lifecycle in search of the best second-use strategies, followed by a comprehensive test program to
verify findings, particularly battery lifetimes. For the field test, researchers will deploy aged EV batteries at
the University of California (UC), San Diego’s campus-wide electric power grid. The results of the study will:
Provide validated tools and data on battery life to industry for battery reuse
Recommendations for EV battery design and manufacturing practices
Identify the necessary regulatory changes to encourage secondary battery use
Assess the economic benefit of second uses
The cost of Li-ion batteries also currently affects the affordability of EVs for consumers. Researchers will do a
technical and economic investigation to see if the potential for reusing Li-ion batteries could lead to
consumers obtaining a cost credit for the remaining value of a used battery, potentially offsetting a portion of
the initial cost to the EV buyer. It might be the case that while a battery no longer has sufficient power for
an EV, it still has the capability to meet the needs of other less demanding applications.
Allocating used electric vehicle batteries to second-use applications also could benefit the environment by
delaying the recycling or disposing of batteries, and by supplying a service that improves the efficiency and
cleanliness of other industries.
Team Members
The CCSE project team includes the UC Davis’s Plug-In Hybrid Electric Vehicle Research Center, the UC
Berkeley, Transportation Sustainability Research Center (TSRC), UC San Diego Strategic Energy Initiatives,
San Diego Gas & Electric, and AeroVironment.
The NREL award to the CCSE team leverages an ongoing UC Davis-CCSE-TSRC study funded by the California
Energy Commission on the repurposing of used EV batteries for home energy storage. The total budget for
the NREL-CCSE second use battery project is approximately $1.3 million with 51 percent of the funding
coming from CCSE and its partners.
This activity is sponsored by DOE’s Office of Energy Efficiency and Renewable Energy. NREL’s cross-cutting
capabilities and expertise in energy storage, advanced vehicles, grid interfaces, system analysis, and solar
and wind energy will provide overall project direction and critical assessment.
NREL is the Department of Energy’s primary national laboratory for renewable energy and energy efficiency
research and development. NREL is operated for DOE by The Alliance for Sustainable Energy, LLC.
###
Visit NREL online at www.nrel.gov
For further information contact NREL Public Relations at 303-275-4090 .
Subscribe to receive new NREL releases by e-mail. Subscribe to RSS feed. About RSS.
Printable Version
Content Last Updated: April 05, 2011
http://www.nrel.gov/news/press/2011/959.html[5/13/2011 5:23:42 AM]

3. PHEV/EV Adoption
• Plug-in hybrid electric vehicles
(PHEVs) and full electric vehicles
(EVs) have massive potential to
reduce U.S. dependence on foreign
oil and emissions…
• …but their high initial battery costs
inhibit rapid proliferation
– EV packs can cost more than $30,000!
• One option to reduce initial battery
cost: reuse it in a second
application following its retirement
from automotive service and obtain
a cost credit for its residual value
Becker, “Electric Cars in the United States: A New Model with Forecasts to 2030”
National Renewable Energy Laboratory 2 Innovation for Our Energy Future

4. Battery Reuse Strategies
Manufactured & Installed • PHEV/EV batteries degraded to
in Automobile
70%-80% of their original
power/capacity are insufficient for
Employed in Automotive automotive use
Application
• These “retired” batteries may still
Refurbished & Installed in
Second Use Application
be highly useful and could be
reused in other applications
Employed in Second Use
Application
• “Second-use” applications could
significantly increase the total
lifetime value of the battery, and
Recycled thus reduce its cost to the
automotive user
National Renewable Energy Laboratory 3 Innovation for Our Energy Future

5. Some Second Use Applications
• Grid-Based Stationary
– Energy Time Shifting
– Renewables Firming
– Service Reliability / Quality
• Off-Grid Stationary
– Backup Power
– Remote Installations
• Mobile
– Commercial Idle Off
– Utility & Rec. Vehicles
– Public Transportation
National Renewable Energy Laboratory 4 Innovation for Our Energy Future

6. Second Use History
• General second use of automotive traction batteries has been studied
before:
– Pinsky, et al., “Electric Vehicle Battery 2nd Use Study”
– EPRI, “Market Feasibility for Nickel Metal Hydride and Other Advanced
Electric Vehicle Batteries in Selected Stationary Applications”
– Cready, et al. “Technical and Economic Feasibility of Applying Used EV
Batteries in Stationary Applications”
• Results showed some promise, but highlighted several barriers:
– Sensitivity to uncertain degradation rates in second use
– High cost of battery refurbishment and integration
– Low cost of alternative energy storage solutions
– Lack of market mechanisms and presence of regulation
– Perception of used batteries
• Due in part to the limited market of PHEV/EVs at the time, no second
use programs have been implemented yet
National Renewable Energy Laboratory 5 Innovation for Our Energy Future

7. Renewed Interest in Second Use Programs
• New opportunities and dynamics for second use of
PHEV/EV batteries are driven by…
– Recent strong interest in PHEV/EVs for reducing emissions and
dependence on imported oil
– Increased need for grid-integrated energy storage to address peak
load reduction, grid stabilization / reliability, energy efficiency, etc.
– Envisioned growth of renewable solar and wind electricity further
increasing the value of grid-integrated energy storage
– Large investment in battery manufacturing for green economy
– Advances in Li-ion batteries with longer life, but still high cost
National Renewable Energy Laboratory 6 Innovation for Our Energy Future

8. Present Second Use & Related Activities
• AEP & EPRI… developing a Community Energy Storage (CES) appliance,
which they’ve stated is “the ideal secondary market we have been seeking for
used PHEV batteries”
• UC Davis… has released an RFP titled “Second Life Applications and Value of
Traction Lithium Batteries” to investigate profitable second use strategies and
develop a Home Energy Storage Appliance (HESA)
• UC Berkeley/CEC… investigated strategies to overcome the battery cost of
plug-in vehicles by the value of integrating post-vehicle battery to grid
• Rochester Institute of Technology… funded by NYSERDA to investigate the
second use of lithium ion batteries
• Nissan… has partnered with Sumitomo to initiate a business plan centered on
recovering and reselling used automotive batteries
• Enerdel … is working with Itochu to develop energy storage systems for
apartment buildings to “help develop a secondary market” for used batteries
• Better Place… is “evaluating … second life applications for used batteries” in
partnership with Renault-Nissan
• DOE / NREL… funded to investigate reducing initial PHEV/EV battery cost via
the second use of automotive lithium ion batteries
National Renewable Energy Laboratory 7 Innovation for Our Energy Future

9. NREL: Uniquely Positioned to Investigate Second Use
Li-Ion Batteries
Energy
Analysis
Utilities & Grids Solar Energy Wind Energy
Hybrid & Electric Vehicles Energy Efficient Commercial & Residential Buildings
National Renewable Energy Laboratory 8 Innovation for Our Energy Future

10. DOE - NREL’s Second Use Project
• Objective: Identify, assess, and verify profitable
applications for the second use of PHEV/EV Li-ion traction
batteries to reduce the cost and accelerate adoption of
PHEV/EVs
• Strategy:
Phase 1: Phase 2: Phase 3:
Assess Verify Facilitate
Merit Performance Implementation
National Renewable Energy Laboratory 9 Innovation for Our Energy Future

11. Phase 1: Assess the Merit
of Second Use Applications
and Strategies
Phase 1: Phase 2: Phase 3:
Assess Verify Facilitate
Merit Performance Implementation
National Renewable Energy Laboratory 10 Innovation for Our Energy Future

12. Application Identification
• All applications are
considered, but high-value /
high-impact ones are most
desirable Numerous grid-connected
applications at consumer to
power plant levels, ranging
from T&D support to energy
• Accurate use profiles and time shifting
economic data are needed
Secondary mobile
applications may also
prove valuable
• Application value and
impact will be estimated
before progressing to a
detailed investigation
National Renewable Energy Laboratory 11 Innovation for Our Energy Future

13. Application Identification
• For each application, consider…
– How does a battery retired from automotive service perform when
subjected to the second use profile?
– What are the projected revenues and costs?
– What are the safety concerns and liabilities?
– How do the performance, life, and cost of a second use battery compare
with those of competing technologies?
– What are the regulatory issues or other barriers specific to this
application?
– Is the scale of this application well suited to the expected availability of
retired PHEV/EV batteries?
National Renewable Energy Laboratory 12 Innovation for Our Energy Future

14. Tool Development & Use
• Must consider value and performance in both automotive
and secondary use environments to calculate total lifetime
battery value
Second
Use
Automotive
Use
Eyer, “Energy Storage for the Electricity Grid: Benefits
and Market Potential Assessment Guide”
National Renewable Energy Laboratory 13 Innovation for Our Energy Future

15. Tool Development & Use
• First, model performance through automotive use
– Consider multiple automotive scenarios, such as various climates,
use profiles, initial sizing strategies, retirement dates, etc.
Scenario 2: Standard
auto use, retired early
Scenario 1: Standard
auto use, retired @ 70%
Scenario 3: Aggressive
auto use, retired @ 70%
National Renewable Energy Laboratory 14 Innovation for Our Energy Future

16. Tool Development & Use
• Next, select a second use application (or aggregation
thereof) and model performance in the second life
– Consider appropriate second use application variables
These example second
use apps retired @ 60%
National Renewable Energy Laboratory 15 Innovation for Our Energy Future

17. Tool Development & Use
• Third, calculate the net
present value of each Scenario 2: $16479
scenario and select the Scenario 1: $15333
optimum use strategy
– Apply a $/mile valuation to
automotive life?
Scenario 3: $8030
– Include both a discount rate
for future revenue and
anticipated increase /
decrease in future second
use revenue
– Account for costs, including
reconfiguration, shipping,
maintenance, etc.
National Renewable Energy Laboratory 16 Innovation for Our Energy Future

18. Tool Development & Use
Scenario 2: $16479
• Some things to consider Early retirement sounds good here…
but under these assumptions the
in a proper analysis… battery is most cost-effective when
never installed in an automobile!
Scenario 1: $15333
– Every time a battery is
replaced in a car, a cost is
incurred to the owner
– Linear battery degradation
may not be a good Scenario 3: $8030
Looks really bad, but
assumption remember the initial
battery cost is assumed
to be much lower!
– If the second use
application is too valuable,
operators may choose new
batteries over used ones
National Renewable Energy Laboratory 17 Innovation for Our Energy Future

19. Tool Development & Use
• Repeat for multiple (aggregations of)
second use applications, identify the
best ones, and calculate an initial
battery price discount
National Renewable Energy Laboratory 18 Innovation for Our Energy Future

20. Tool Development & Use
• Questions the tool will be asked to answer…
– How do different automotive use profiles, environmental conditions, and
lifetimes affect performance in the second use application?
– What is the total lifetime value of the battery, in both its automotive and
second use applications?
– What is the sensitivity of total lifetime value to use history and other
parameters?
– What is the uncertainty in the complete analysis?
National Renewable Energy Laboratory 19 Innovation for Our Energy Future

21. Optimizing Use Strategies What design and
manufacturing practices
should be employed?
• For a given second use Manufactured & Installed
application, there can be many in Automobiles
How should the
different ways to implement it battery be used and
retired?
Employed in Automotive
• Changing these variables can Applications
have a significant impact on How do you collect,
screen, refurbish, certify,
total lifetime value and general & distribute the batteries?
feasibility Refurbished for Second
Use Applications
How do you manage
ancillary systems, the
• In this segment, the use use of multiple packs,
and servicing needs?
strategy of the battery is Employed in
optimized via the developed Second Use Applications
tools and practical
considerations Who owns
the battery at
each stage?
Recycle
National Renewable Energy Laboratory 20 Innovation for Our Energy Future

22. Optimizing Use Strategies
• Example timeline …
Decision to remove /
replace battery in auto
Battery manufactured based on…
& installed in auto • In-car performance? Decision to retire / replace
• Second use value? battery based on…
• Replacement cost? • Safety concerns?
• Cont’d second use value?
• Replacement cost?
• Recycled value?
Auto continues
with new battery…
Regular performance
checks to support Second use service
retirement election continues with battery
replacement
Regular performance
checks to support
Retired auto battery
retirement election
tested, certified, and Battery recycled
reconfigured
Battery shipped
and installed for
second use
National Renewable Energy Laboratory 21 Innovation for Our Energy Future

23. Selecting the Best Applications & Strategies
• Maximum total lifetime value of the battery (biggest
initial cost reduction)
• High feasibility of implementation
• Matched well to the size of the PHEV/EV market
National Renewable Energy Laboratory 22 Innovation for Our Energy Future

24. Phase 2: Verify Performance
In Second Use Applications
Phase 1: Phase 2: Phase 3:
Assess Verify Facilitate
Merit Performance Implementation
National Renewable Energy Laboratory 23 Innovation for Our Energy Future

25. Acquire Aged Li-Ion Batteries
• Prefer field-tested
Courtesy chevrolet.com Courtesy fiskerautomotive.com
batteries from (pre)
production PHEV/EVs
• Accelerated aging via Courtesy nissanusa.com Courtesy thinkev.com
lab testing is also an
option, but may not
ensure correlation with
actual field use
Courtesy miniusa.com
• Mass-produced cell Courtesy teslamotors.com
and pack designs are
required
National Renewable Energy Laboratory 24 Innovation for Our Energy Future

26. Conduct Long-Term Testing
• Subject the aged batteries to the expected use profile and
conditions of the second use application to verify performance
and degradation predictions and lifetime valuations
• Lab testing for precise
control of conditions
• Field testing for final
demonstration
NREL’s Distributed
Energy Resources Test
Facility could serve as a
venue for this phase
National Renewable Energy Laboratory 25 Innovation for Our Energy Future

27. Phase 3: Facilitate Implementation of Second Use Programs
– Disseminate study findings to inform the market of the
potential profitability of the second use of traction batteries
– Provide validated tools and data to industry
– Develop design and manufacture standards for
PHEV/EV batteries that facilitate their reuse
– Propose regulatory changes to encourage the reuse of
retired traction batteries in other applications
Phase 1: Phase 2: Phase 3:
Assess Verify Facilitate
Merit Performance Implementation
National Renewable Energy Laboratory 26 Innovation for Our Energy Future

28. DOE-NREL’s Second Use Program Status
Where we are now
Phase 1: Phase 2: Phase 3:
Assess Verify Facilitate
Merit Performance Implementation
• High-level objectives and strategies have been formulated
• Work has begun on researching possible second use applications
and on tools to forecast performance / degradation
• Discussions with possible partners are under way
National Renewable Energy Laboratory 27 Innovation for Our Energy Future

29. What’s Next?
• NREL is currently seeking partners to investigate the reuse of retired
PHEV/EV traction batteries to reduce vehicle cost and emissions as
well as our dependence on foreign oil
• A Request for Proposal (RFP) will be issued in April 2010 seeking
subcontractors to support all aspects of this effort
• A workshop to solicit industry feedback on the entire process is also
being planned
National Renewable Energy Laboratory 28 Innovation for Our Energy Future

30. Acknowledgements
• This activity is funded by the DOE Vehicle Technologies
Program, Energy Storage Technology
• We appreciate the support provided by DOE program
managers
– David Howell
– Steve Goguen
• Technical questions regarding Battery Second Use
should be directed to Jeremy Neubauer at 303-275-
3084 or jeremy.neubauer@nrel.gov
• Questions regarding the request for proposals should
be directed to Kathee Roque at kathee.roque@nrel.gov
National Renewable Energy Laboratory 29 Innovation for Our Energy Future