1
NOVEMBER /// 2010
Large Format Lithium
Power Cells for
Demanding Hybrid
Applications
Adam J. Hunt
Manager of Government Programs
2011 Joint Service Power Expo
Power to Sustain Warfighter Dominance
Myrtle Beach, SC
May 4, 2011
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• Ener1 Overview • Negative Active Materials Comparison
• Lithium titanate vs. other common materials
• Lithium titanate characteristics • EnerDel LTO Cell Performance
• Small cells
• Large cells
• Multiple cells in series
• Conclusions & Final Remarks
CONTENTS
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GLOBAL SUPPLY STRATEGY
ENER1 / CORPORATE HQ / NYC, U.S.
ENER1 EUROPE / SALES & MARKETING / Paris, France
ENERDEL / Indianapolis, IN, U.S.
ENERDEL / Noblesville, IN, U.S.
ENERDEL / Mount Comfort, IN, U.S.
ENERDEL / R&D CENTER / Japan
ENER1 KOREA / Korea
WANXIANG / SHANGHAI, CHINA
THINK GLOBAL / Norway
Total Employees: 750 （Excl. China/Think)
Symbol/NASDAQ: HEV
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Easily replicated production processes allow us to expand capacity and locate facilities in-country near clients’ facilities
• Ener1 Lithium Group Established in 1990 • Delphi Lithium Group 1998 • EnerDel 2004 • Total Area: ~ 98,000 ft2
• Production & R&D of Lithium-Ion Cells for multiple applications
• Established in 2009 • Floor Space -38,500 ft2 • BMS Engineering & Test
U.S. FACILITIES
• Lease signed January 2010 • Total Area: 400,000 ft2 • Production Lithium-Ion Cells for
multiple applications • Final Pack Assembly Operations • Production Launch in May • Made possible by $118.5 million in
federal grant funding under the ARRA stimulus package
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EnerDel battery system concept provides maximum flexibility to meet
customer’s requirement
TOTAL SOLUTION PROVIDER FOR LI-ION
BATTERY SYSTEM
HEV System EV System
CELL • Advanced Prismatic Design
• High Performance Li-Ion Cells
SYSTEM
• High Speed Vehicle Communication
• Robust Battery System
• Integrated reuse design concept
MODULE
• Easy Maintenance Module Concept
• Integrated Thermal Management
• Voltage & Temperature Monitoring
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NEGATIVE ACTIVE MATERIAL COMPARISON
• Graphite – Most common active material for existing lithium ion cells
– Most energy density per volume
• Non-graphite carbon – Less reaction with electrolyte than graphite
– Higher power than graphite
– Longer life than graphite
• Lithium Titanate (Li4Ti5O12) – No reaction with electrolyte
– Less impedance
– Longer life
– Less Energy density
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NEGATIVE ACTIVE MATERIAL COMPARISON
Characteristic Graphite Carbon Lithium
Titanate
Long Life 3 2 1
Power 3 2 1
Energy 1 2 3
Low temperature 3 2 1
Safety 3 2 1
Lithium Titanate cell performance will be presented in this presentation
1 – BEST 2 – BETTER 3 - GOOD
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The Titanate Anode
• A very stable oxide best known for its safety and long cycle life • Theoretical capacity of 165 mAh/g is about half that of graphite (372 mAh/g) • It operates at 1.5V vs. Li which is above the voltage at which Li dendrites can occur • Less than 0.2% volumetric change from fully discharged Li4Ti5O12 to fully charged Li7Ti5O12 titanate (for comparison, graphite is 9% and silicon is 300%)
<J. Electrochem. Soc. 146(1999) 857>
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LTO CHARACTERISTICS
• Advantages
–Zero strain material • LTO ~ 0.02 % volume change
• Graphite ~ 9% volume change
–No lithium dendrites
– Less impedance than graphite
↓
High power
Good low temperature performance
Long life
Safety
• Disadvantages
– Lower Energy Density
– Lower Voltage Fig. XRD patterns of LTO material at different DOD
10 20 30 40 50 60 70 80
2 Theta / degree (CuKa)In
ten
sit
y /
Arb
. u
nit
DOD 0%
DOD 40%
DOD 90%
DOD 100%
(11
1)
(31
1) Cu
, (4
00
)
(31
1) C
u
(51
1)
(33
3)
(44
0)
(53
1) Cu
, (5
33
)
(62
2)
(44
4)
(22
2)
Li4Ti5O12 - spinel (LTO)
Li4Ti5O12 + xLi+ + xe- ↔ Li4+xTi5O12
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LTO Anode
Stan Whittingham SUNY
• The Li
insertion in
titanate occurs
at ~1.5V, well
above the
voltage at
which Li
deposition
occurs
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LTO negative shows less heat generation than graphite negative
THERMAL STABILITY OF LTO
Scan range; 50 – 350 oC Scan rate: 10 oC/min
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LTO HALF CELL RESULTS
• very flat charge or discharge curve
• very small irreversible capacity
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LTO HALF CELL RESULTS
• discharge rate capability is exceptional
• excellent for power applications (this is equivalent to discharge rate capability in a full cell)
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ENERDEL SMALL CELL DESIGN FOR LIGHT-DUTY VEHICLE APPLICATIONS
DESCRIPTION SPECIFICATION
Application Light-duty vehicle
Nominal Capacity 1.8Ah 5Ah
Max Voltage 2.8V
Min voltage 1.5V
Cell size 145 x 130 x 5 mm 200 x 111 x 5 mm
Chemistry LTO/LMO
15
25
30
35
40
45
50
55
60
65
70
0 10 20 30 40 50 60
Time / Min
Te
mp
era
ture
/ o
C1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
Vo
lta
ge
/ V
Cell Temperature
Voltage
25
30
35
40
45
50
55
60
65
70
0 10 20 30 40 50 60
Time / Min
Te
mp
era
ture
/ o
C
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
Vo
lta
ge
/ V
Cell Temperature
Voltage
TEMPERATURE INCREASE AT HIGH POWER CYCLE
LTO/LMO 1.8Ah Cell Graphite/LMO 1.8Ah Cell
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5 AH FULL CELL: HIGH TEMPERATURE CYCLING
• 2C cycling at 55°C
• excellent high temperature capacity retention
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0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
0 500 1000 1500 2000 2500 3000
Cycle Number
Dis
ch
arg
e c
ap
acit
y /
Ah
CYCLE LIFE
• No capacity loss under severe cycling conditions.
55oC 5C charge 5C discharge 100% DOD
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EXTREME ABUSE TEST, LTO CELLS
-1.0
0.0
1.0
2.0
3.0
4.0
5.0
6.0
0 2 4 6 8 10 12 14 16 18
Time (min)
Vo
lta
ge
(V
)
0
30
60
90
120
150
180
210
Te
mp
era
ture
(C
)
Cell Voltage
Cell Temperature
Room Temperature
Nail penetrates
Overcharge and nail penetration
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HEV BATTERY PACK WITH ENERDEL LTO CELLS
We can reduce the battery size by one-half compared to existing Ni-MH pack
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LARGER SIZE LTO CELL
• Mixed oxide was used for the positive active materials instead of LMO
DESCRIPTION SPECIFICATION
Application Heavy-duty vehicle
Nominal Capacity 9.5Ah
Max Voltage 2.75V
Min voltage 1.6V
Cell size 172x 253 x 5.8 mm
Chemistry LTO/Mixed Oxide
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DISCHARGE PROFILE– 9.5AH CELL
1
1.2
1.4
1.6
1.8
2
2.2
2.4
0 2 4 6 8 10 12
Vo
ltag
e_V
Discharge capacity_Ah
1C
3C
5C
10C
20C
25C
0
0.5
1
1.5
2
2.5
3
0 2 4 6 8 10
Vo
lta
ge
(V)
Discharge_Capacity(Ah)
Cycle 3_30C
Cycle 803_26C
Discharge profile comparison at 3rd
cycle and 803rd cycle
Rate Capability
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CYCLE LIFE – 9.5AH CELL
Capacity loss is not observed through first 1000 cycles.
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THERMAL TEST WITH 3 CELLS IN SERIES (30°C)
8 points of the cell temperature were measured
Max 10oC increase with 25C continuous discharge
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3mm diameter nail, penetrating with a rate of 80 mm/s
NAIL PENETRATION (9.5AH CELL)
•No thermal event was observed. No explosion, no fire, no flame, no smoke. Irreversible cell damage. •EUCAR /SAE J2464 hazard level = 2 •Cell was not shorted right away. It took 1 hr for the cell voltage to reach 0V •Positive terminal temperature reached 32°C
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•SAFE
•LARGE FORMAT
•HIGH POWER
•LONG LIFE
•MECHANICALLY STABLE
•MADE IN THE UNITED STATES
•COMPATIBLE WITH EXISTING ENER1 MODULE STRUCTURE
CONCLUSIONS
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ACKNOWLEDGEMENT
Ener1 would like to thank the Department of Energy – National Energy Technology Laboratory for funding under cooperative research agreement
DE-FC26-08NT01929 and the U.S. Army Tank Automotive Research, Development and Engineering Center (TARDEC) for Financial Support in the
continued refinement and demonstration of the Titanate High-Power cells used for W56HZ-09-C-0681.
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THANKS FOR YOUR ATTENTION!
PLEASE VISIT US IN BOOTH #110
ADAM J. HUNT – MANAGER OF GOVERNMENT PROGRAMS
(317)585-3464
WWW.ENER1.COM
