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In-Vehicle Evaluation of 

Lower-Energy Energy Storage 

System (LEESS) Devices

PI: Jeff Gonder

Team: Jon Cosgrove, Ahmad Pesaran and Matt Keyser

National Renewable Energy Laboratory

2014 Annual Merit Review and Peer Evaluation Meeting

Washington, D.C.

June 18, 2014

NREL/PR-5400-61855

Project ID: VSS129

This presentation does not contain any proprietary, confidential, or otherwise restricted information.
2

Overview

Project Duration: 2012–2014

Percent Complete: 70%

• Cost

• Technical target setting

• Risk aversion, and constant 

advances in technology

Total FY13-FY14 VSST Funding: 

$300K

Equivalent DOE ES program cost 

share over project duration

Timeline

Budget

Barriers Addressed

• USABC: Foundational analysis for 

HEV LEESS targets

• Ford: CRADA facilitating vehicle 

conversion

• JSR Micro: Provided LIC modules for 

testing

• Maxwell Technologies: Provided 

ultracapacitor (EDLC) modules

• NREL is project lead

Partners

CRADA = Cooperative Research and Development Agreement

EDLC = electrochemical double-layer capacitors

ES = Energy Storage

HEV = hybrid electric vehicle

LIC = lithium-ion capacitor

USABC = United States Advanced Battery Consortium

VSST = Vehicle Systems Simulation and Testing
3

Relevance for DOE Fuel-Saving Mission

• HEVs effectively reduce per-vehicle fuel use

• Incremental cost remains a barrier to a wider market 

penetration

o HEVs still only 3% of new car sales*

o ESS arguably the largest cost contributor

• ESS cost reductions/performance improvements 

improved vehicle-level cost vs. benefit

o Increase market demand and aggregate fuel savings

* HybridCars.com 2013 calendar year sales dashboard: http://www.hybridcars.com/december-2013-dashboard/

ESS = energy storage system
4

Relevance for Addressing Barriers

• Cost

o Seek to improve cost effectiveness of fuel-saving HEV 

technology

• Technical target setting

o Establish targets for device developers focused on costeffective fuel-saving goal

o Confirm performance of candidate devices in vehicle 

systems context

• Risk aversion and constant advances in technology

o DOE/NREL helping to evaluate technologies outside the 

traditional HEV ESS paradigm

o Reusable test platform can be used to evaluate different 

systems as they become available—simply swapping out 

the LEESS devices under test
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• Specific LEESS considerations

o Technical evaluation—can it do the job?

– Validation testing related to (recent) USABC 

technical targets and supporting analysis 

o Potential for lower cost with less energy?

o Potential benefits from alternative 

technology?

– Better ESS life?

– Better cold temperature performance?

Objectives

• Explore opportunities to improve HEV ESS cost effectiveness, 

ultimately leading to increased market penetration and fuel 

savings

o Collaborate with OEMs and suppliers around LEESS concept

o Perform vehicle conversion and evaluate devices in the test bed

Project 

Focus in 

FY14

OEM = original equipment manufacturer
6

Milestones & Response to Reviewer Comments

Date Milestone or 

Go/No-Go 

Decision

Description Status 

(as of April 2014)

12/31/2013 Milestone Progress update Completed

3/31/2014 Milestone Progress update

Completed – 1st system 

testing results 

summarized here

6/30/2014 Milestone Testing results with 2nd

LEESS system

Bench testing Maxwell 

EDLC modules

9/30/2014 Milestone

Testing results with 3rd

LEESS system Still confirming what 

the 3rd system will be

• This project was not reviewed in FY13 so there are no 

comments to address
7

Approach/Background: Build on Previous Analysis Supporting 

USABC LEESS Target Setting

• NREL analyzed full-HEV fuel 

savings sensitivity to ESS 

energy content

o Working with an Energy 

Storage Tech Team 

Workgroup

o Re-evaluating past ESS targets 

established in the late 

1990s/early 2000s

• Results suggested power-assist 

HEVs can still achieve high fuel 

savings with lower energy and 

potentially lower cost ESS*

• USABC established targets and began supporting device developers

o See: http://www.uscar.org/guest/article_view.php?articles_id=87

o Open to any ESS technology (very high power batteries, EDLCs, or LICs)

* Gonder, J.; Pesaran, A.; Howell, D.; Tataria, H. “Lower-Energy Requirements for 

Power-Assist HEV Energy Storage Systems—Analysis and Rationale.” Proceedings 

of the 27th International Battery Seminar and Exhibit; Mar 15-18, 2010, Fort 

Lauderdale, FL. http://www.nrel.gov/docs/fy10osti/47682.pdf

DOH = degree of hybridization

UDDS = Urban Dynamometer Driving Schedule (city testing)
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Approach/Background: Draw from Past Evaluation for GM of 

Replacing NiMH ESS with EDLCs in the 42-V Saturn Vue BAS HEV

• Motivation: EDLC potential for superior cycle life, cold temperature 

performance, and long-term cost reductions

• Bench-tested EDLCs and retrofitted vehicle to operate in three 

configurations

NiMH = nickel metal hydride; BAS = belt alternator starter (“mild” HEV)

Photos by Jeff Gonder and Jason Lustbader, NREL

Findings: 42-V HEV with ultracapacitors performed at least as well as the 

stock configuration with a NiMH battery
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Approach: Create a Full-HEV Test Bed for In-Vehicle LEESS 

Device Evaluation

• Modified a 2012 Ford Fusion Hybrid

o CRADA with Ford to facilitate

• Enable operation on alternative LEESS devices

o Second set of production control modules to 

interface with LEESS pack

o Custom state estimation algorithm

o dSpace MicroAutoBox (MABx) for control 

prototyping—signal intercept/replacement, safety 

controls

• Maintain stock operating capability (using 

production NiMH cells)

o Able to switch between operation using the stock 

battery and using the LEESS device under test

o Provides back-to-back performance comparison

Images: A. Fusion test platform; 

B. Production battery showing Bussed 

Electrical Center (BEC), Battery Pack Sensor 

Module (BPSM), and Battery Energy Control 

Module (BECM); C. Alternative LEESS test 

configuration mounted in the vehicle’s trunk; 

D. Custom Simulink state estimation model.

A.

B.

C.

D.

Photos by John Ireland and Jon Cosgrove, NREL
10

Approach: Perform Comparison Testing between Various LEESS 

Devices and the Production Battery System

• Conduct bench testing 

o Device characterization/benchmarking against 

production ESS

o Obtain state estimator calibration data

• Conduct in-vehicle performance testing

o Shakedown testing and control tuning to obtain 

desired hybrid functions with LEESS devices

o Acceleration comparison testing

• Conduct chassis dynamometer testing for 

fuel economy and hot/cold performance 

comparison

o Test cycles including

− FTP/UDDS at 75°F, 20°F, and -5°F

− HFET and US06 at 75°F

− SC03 at 95°F

o Data and vehicle CAN traffic recorded using the 

MABx

CAN = controller area network; FTP/UDDS = Federal Test Procedure/Urban 

Dynamometer Driving Schedule (city testing); HFET = Highway Fuel Economy Test; 

SC03 = hot test cycle with air conditioning; US06 = aggressive speed/acceleration 

test cycle

Photos by John Ireland, Petr Sindler and 

Jon Cosgrove, NREL
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Accomplishments: Bench Testing Completed on First LEESS (LIC) 

under Evaluation

• LIC modules from JSR Micro

o Asymmetric storage device with 

battery and ultracapacitor-type 

characteristics

• Rated energy comparison

o 96 cell LIC: 260 Wh*

o 204 cell production NiMH: 

1,370 Wh**

• Bench tested at multiple 

temperatures

o Static capacity test

o Hybrid pulse power 

characterization (HPPC)

o Expected US06 power profile

• Results indicate LIC 

impedance 2-3x less than 

NiMH**

Figure courtesy 

of JSR Micro

*Assuming 175 V – 350 V maximum in-vehicle operating window 

**Based on fact sheet published by Idaho National Laboratory (INL): 

www1.eere.energy.gov/vehiclesandfuels/avta/pdfs/hev/batteryfusion4699.pdf
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Accomplishments: Successfully Completed Conversion; 

Conducted 0-60 mph Acceleration Comparison Testing*

• Observed comparable 

performance between production 

NiMH and LEESS LIC configurations

o Hybrid operation

o Equivalent 0-60 mph acceleration 

times

* Simply for comparison and not intended to be official performance specifications. 

Runs conducted with extra mass of duplicate ESS/conversion equipment, and at high altitude.

Photo by Petr Sindler, NREL
13

Accomplishments: In-Vehicle Dynamometer Testing—Compared 

Voltage Range of Production NiMH vs. Three LIC Configurations

• Evaluated several LIC scenarios in addition to the production configuration

o LIC-High: Energy constrained only by vehicle and device voltage limits

o LIC-Med: Artificially reduced upper voltage limit to constrain energy

o LIC-Low: Further reduced upper voltage limit for most constrained evaluation 

Voltage (V)

Voltage Levels During UDDS Testing
14

Accomplishments: In-Vehicle Dynamometer Testing—Compared 

Fuel and Energy Use of NiMH vs. LIC Configurations

• Small fuel use differences 

between the HEV 

configurations—all show 

significant savings compared 

to the non-hybrid vehicle

• Also measured energy 

window used by each ESS 

configuration for each cycle

Energy out for electric 

launch/assist

Cumulative ESS 

Wh to vehicle

Energy return from 

charging/regenerative braking

Charge sustaining over 

cycle (no net energy use)

In-use “Energy Window” defined by 

(max – min) for the particular cycle

Total 

energy

Energy

window 

actually 

used
15

Accomplishments: In-Vehicle Dynamometer Testing—Compared 

NiMH and LIC-Low Scenarios (among others) Charging (regenerative braking) Discharging (assist)

-200 0 200 400 600 800 1000 1200 1400 1600

-60

-40

-20

0

20

40

60

80

100

120

140

time [sec]

Spd[mph], Energy Profile[Wh], Fuel[g/10] 

NiMH Case Speed

NiMH Energy Profile

NiMH Case Fuel

LIC Case Speed

LIC Energy Profile

LIC Case Fuel

≈ 170 

Wh

≈ 60 Wh

0 100 200 300 400 500 600 700

-150

-100

-50

0

50

100

time [sec]

Spd[mph], Energy Profile[Wh], Fuel[g/10] 

NiMH Case Speed

NiMH Energy Profile

NiMH Case Fuel

LIC Case Speed

LIC Energy Profile

LIC Case Fuel

US06 Fuel Use and Energy Window

Charging (regenerative braking)

Discharging

(assist)
16

Accomplishments: In-Vehicle Dynamometer Testing—Summarizing 

Fuel Use and Energy Window Observations to Date

Comparison over All Cycles and Configurations

Significantly reduced energy window resulted in negligible fuel 

consumption difference on most cycles and small increase on US06 test

LIC-Low and NiMH 

US06 scenarios 

LIC-Low and NiMH 

UDDS scenarios 
17

• USABC (Chrysler, Ford, GM, plus DOE with lab input)

o Collaborated on precursor analysis that established the LEESS 

performance targets for power-assist HEVs

• Ford Motor Company

o CRADA facilitating the vehicle conversion

• JSR Micro

o Provided modules for evaluation and related technical 

information/support

• Maxwell Technologies

o Provided EDLC modules as next system to test

• U.S. DOE—Cross-office collaboration

o Cost-shared support between two Vehicle Technologies Office activities

− Vehicle Systems Simulation and Testing (VSST)

− Energy Storage (ES)

Collaboration and Coordination with Other Institutions
18

• Need to complete additional JSR LIC testing based on feedback from 

collaborators

o Evaluate any adverse LEESS impact on desired vehicle attributes (e.g., energy 

reservoir for passing acceleration and engine off at idle under high accessory 

load)

o Evaluate additional scenarios where LIC capabilities could be a positive 

differentiator (e.g., very cold operation down to -5°F) 

• Still need to assess performance capability and any similarities/ 

differences between alternative LEESS devices (as planned)

• Should consider possible performance and cost differences from 

HEV system changes designed to maximize the strengths and 

minimize the weaknesses of a given LEESS device

o The current single-component replacement approach gives a good initial 

assessment, but an optimized system might include other powertrain changes

• Whether as a drop-in replacement or an optimized system, LEESS 

suppliers need to achieve cost targets to beat out incumbent 

battery technologies

Remaining Challenges and Barriers
19

• Wrap up JSR LIC testing

o Passing acceleration tests

o 95°F SC03 (and extended idle periods) for air conditioning comparison case

o Very cold (-5°F) operation

• Complete bench testing followed by in-vehicle evaluation with 

additional LEESS devices

o Next system will be Maxwell ultracapacitor modules

• Evaluate design adjustment opportunities (and resulting 

cost/fuel economy implications) of optimizing the HEV system 

around a high-power LEESS

o For example, could motor power be increased?

o Or could similar benefits be obtained from a lower voltage system?

• Conduct rigorous business case assessment combining evaluation 

results with supplier cost projections

Potential Future Work
20

• HEVs can save a lot of fuel, but still have low market penetration

o Improving ESS cost vs. benefit could increase penetration and aggregate savings

• Through collaborations across DOE VTO and with industry partners, NREL 

created an HEV test bed and is using it to evaluate LEESS devices

o Assessing nontraditional HEV ESS devices in a vehicle systems context

• Results to date suggest technical viability for a LEESS HEV

o Small energy LIC conversion configurations achieved equal 0-60 mph acceleration and 

very similar fuel economy to production system

o As long as critical attributes (such as engine start under worst-case conditions) can be 

retained, considerable ESS downsizing may minimally impact fuel savings

• Published and presented the results and received positive feedback

• Proposed next steps include:

o Conducting additional LIC system tests in response to comments/suggestions from 

partners (cold temperature performance, supporting accessory loads, etc.)

o Completing planned testing on additional LEESS devices

o Evaluating potential benefits from HEV system optimization around a LEESS device

o Applying the performance evaluation results and supplier cost estimates to assess 

potential LEESS HEV business cases 

Summary
Technical Back-Up Slides

(Note: please include this “separator” slide if 

you are including back-up technical slides 

(maximum of five). These back-up technical 

slides will be available for your presentation 

and will be included in the DVD and Web PDF 

files released to the public.)
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US06 Profile Comparison: Stock Battery (in vehicle) vs. JSR 

Micro LIC (in lab)

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23

In-Vehicle Dynamometer Testing:

Comparing NiMH and LIC-High Scenario

-200 0 200 400 600 800 1000 1200 1400 1600

-60

-40

-20

0

20

40

60

80

100

120

140

time [sec]

Spd[mph], Energy Profile[Wh], Fuel[g/10] 

NiMH Case Speed

NiMH Energy Profile

NiMH Case Fuel

LIC Case Speed

LIC Energy Profile

LIC Case Fuel

UDDS Fuel Use and Energy Window

Charging (regenerative braking)

Discharging

(assist)

≈ 170 

Wh

≈ 120 

Wh
24

In-Vehicle Dynamometer Testing:

Comparing NiMH and LIC-Low Scenario

UDDS Fuel Use and Energy Window

Charging (regenerative braking)

Discharging

(assist)

-200 0 200 400 600 800 1000 1200 1400 1600

-60

-40

-20

0

20

40

60

80

100

120

140

time [sec]

Spd[mph], Energy Profile[Wh], Fuel[g/10] 

NiMH Case Speed

NiMH Energy Profile

NiMH Case Fuel

LIC Case Speed

LIC Energy Profile

LIC Case Fuel

≈ 170 

Wh

≈ 60 Wh
25

In-Vehicle Dynamometer Testing:

Comparing NiMH and LIC-Low Scenario

UDDS Fuel Use and Energy Window

Charging (regenerative braking)

Discharging

(assist)

-200 0 200 400 600 800 1000 1200 1400 1600

-60

-40

-20

0

20

40

60

80

100

120

140

time [sec]

Spd[mph], Energy Profile[Wh], Fuel[g/10] 

NiMH Case Speed

NiMH Energy Profile

NiMH Case Fuel

LIC Case Speed

LIC Energy Profile

LIC Case Fuel
26

0 100 200 300 400 500 600 700 800

-80

-60

-40

-20

0

20

40

60

time [sec]

Spd[mph], Energy Profile[Wh], Fuel[g/10] 

NiMH Case Speed

NiMH Energy Profile

NiMH Case Fuel

LIC Case Speed

LIC Energy Profile

LIC Case Fuel

In-Vehicle Dynamometer Testing:

Comparing NiMH and LIC-Low Scenario

HWFET Fuel Use and Energy Window

Charging (regenerative braking)

Discharging

(assist)

≈ 110 

Wh

≈ 50 

Wh