Transcript Research Needs: A Transportation Perspective "Applied Problems

Research Needs: A Transportation Perspective
"Applied Problems
Can Be Addressed In A Fundamental Way"
Presented to
The Workshop on Basic Research Needs for Electrical Energy Storage
Tien Q. Duong
Office of FreedomCAR & Vehicle Technologies
April 2, 2007
Outline
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Introduction
PHEV Overview
Battery (and UltraCapacitor) Status
PHEV Battery Requirements
Technology Development Roadmap
Program Elements
Research Directions and Needs
Conclusion
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Introduction
Steady Progress has been made over the years
 Consumer acceptance of HEVs is partially due to the durability of the
NiMH batteries.
 Cost of lithium-ion batteries for consumer electronics continues to
decline – presently it is below that of NiCd and NiMH batteries.
1,800
$/kWh Cost Trend in Japan – Small
Rechargeable Cells Averaged Across Sizes
1,600
$/kWh
1,400
1,200
1,000
800
NiMH
NiCd
Li-ion
600
400
200
0
J M S
J M S
J M S
J M S
J M S
J M S
J M S
J M S
1999
2000
2001
2002
2003
2004
2005
2006
Source: TIAX, based on METI data
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Introduction
Lithium-ion is viewed as the most commercially
viable chemistry for PHEVs due to its potential
for much higher energy and power density.
Further improvements are needed before a
larger penetration of HEVs and PHEVs can
take place into the marketplace.
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PHEV Overview
Design Strategy
All-electric
HEV Charge-depleting
Power (kW)
SOC (%)
100%
70
Engine
Motor
SOC
Power (kW)
SOC (%)
100%
70
Engine
Motor
SOC
90%
60
80%
50
40
70%
40
70%
30
60%
30
60%
20
50%
20
50%
10
40%
10
40%
0
30%
0
30%
-10
20%
-10
20%
-20
10%
-20
10%
-30
0%
-30
0%
60
50
0
5
10
15
20
25
Distance (miles)
30
35
40
0
5
10
15
20
25
30
35
90%
80%
40
Distance (miles)
 The “all-electric” strategy leads to more petroleum displacement and
less emissions with some potential performance penalty; but the cost
increase for the electric power-train may not be justifiable.
 The “HEV charge-depleting” strategy leads to the same “equivalent”
electric range, a slightly lower fuel economy, higher tailpipe
emissions, and an affordable cost without sacrificing performance.
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PHEV Overview
Battery Operation
Battery State of Charge (SOC)
(Fully Charged)
100%
(Fully Discharged)
80%
60%
40%
20%
0%
Uncharged
Capacity
HEVHEV
HEV
HEV
CS only: 300-500 Wh, 25-40 kW (10
sec) @70% SOC, 300,000 cycles
~1-2 kWh, P/E = 15-20
CS: 300-500 Wh, 25-40 kW (10 sec)
Charge Depleting
@30%
SOC, 300,000 cycles
PHEV
PHEV
PHEV
PHEV
EV
Charge Sustaining
CD: Energy scaled for range (10-40
Unused
Energy
miles),
5,000
deep discharge cycles
~5-15 kWh, P/E = 5-18
EV
EV
EV
CD only: Energy scaled for 100+ mile
range, 1,000+ deep discharge cycles
>40 kWh, P/E = 2
0
0
20
40
60
80
100
20
40
60
80
100
Battery Size (kWh)
 Impact on battery life with these two modes
of operation is not fully understood.
Charge Depleting (CD)
Charge Sustaining (CS)
Unused Energy
Battery Size (kWh)
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Status: HEV Batteries
 Conventional lithium-ion batteries for HEVs are nearly
ready for commercialization
 Gradual displacement of NiMH batteries is expected, Li-ion
promises reduced cost, increased performance, and longer life.
 Major R&D focus remains on cost reduction; current cost
is approximately 2 times the goal. Additional issues
include
 Life: projections of 10-15 years are based on limited data
 Abuse tolerance
 Low-temperature performance
 Emerging technologies include advanced materials
 Li4Ti5O12 and alloy composite negatives
 LiFePO4, LiMnPO4, and high voltage layered and layered-spinel
positives
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Status: HEV Batteries
Power / Available Energy
Power level decreases with time
Energy window at constant power decreases with time
RPT0 10-s Discharge
70000
87500
RPT9 10-s Discharge
RPT0 10-s Regen
60000
75000
50000
62500
40000
50000
30000
25-kW Line
37500
20000
25000
10000
12500
0
0
100
200
300
400
500
600
700
800
Regen Power (x25/20), W
Discharge Power, W
RPT9 10-s Regen
0
900
BSF-scaled Energy Removed at the C/1 Rate, Wh
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Status: EV Batteries
 Lithium batteries for EVs are far from commercialization
 Lithium metal polymer suffers from poor cycle life. A stiffer solid
polymer electrolyte with significantly improved ionic conductivity at
room temperature is required.
 Lithium sulfur is still immature. Improved lithium and sulfur
utilization is needed to improve cycle life. No practical cells have
been built for evaluation.
 Major R&D is focused on suppressing dendrite formation and
stabilizing the lithium interphase
 Additional barriers include cost, low specific energy and poor cycle
and calendar life.
 Gradual advances in energy density and performance are planned,
permitting evolution from HEVs, to PHEVs, to EVs.
 Emerging technologies include
 Composite electrolytes with a hard non-conducting component and a
softer conducting component.
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Status: EV Batteries
Power Fading at 80% Depth of Discharge Limits Battery Life
120
Relative power or energy, %
100
80
60
C/3 energy
40
Power at 80% DOD
Power at 0% DOD
20
0
0
200
400
600
800
1000
1200
1400
Cycles
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Status: UltraCapacitors
 Currently funded development is limited to symmetric
EDLCs for micro hybrids
 Technologies with acetonitrile and propylene carbonate solvents are being
considered.
 Systems utilizing acetonitrile solvent have better power performance.
 Current ultracapacitors are approaching the USABC 42V Start/Stop
performance requirements of life, weight and volume.
 Advantages: High power, performance not affected by
low temperatures, long cycle and calendar life
 Issues
 Cost: Projected to cost 2-4 times the USABC 42V goal.
 Energy density: Restricts use in automotive applications, 30 Wh system
requires ~13 liters (< 3 Wh/l and < 3 Wh/kg).
 Research direction and current efforts
 Lower cost carbon
 Novel low cost cell and module packaging
 Higher voltage carbon and electrolyte
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Status: Abuse Tolerance
 Lithium-ion batteries can be made abuse tolerant for vehicle
applications
 Cell, modules, and battery level electronic and mechanical controls are
necessary.
 Well-designed thermal management at the module and battery levels is
critical to mitigate thermal runaway (and extend life).
 These components add cost, weight, and volume. Thus, improved
inherent abuse tolerance is desired.
 Current Activities
 Laboratories perform cell and component (positive, negative, etc.) level
investigations to determine operational limits of current technology.
 Laboratories and universities investigate material stabilities.
 Fundamental Question:
 How can material properties be modified to maintain high power
and energy, but with significantly enhanced thermal conductivity
to help alleviate thermal runaway risks?
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USABC Goals for Advanced
Batteries for PHEVs
Power requirements are set to allow an all-electric operation under
Urban Dynamometer Driving Schedule (UDDS)
in charge-depleting mode
High Power/
Energy
Ratio
Battery
•High
Energy/
Power Ratio
Battery
miles
10
40
Peak Pulse Discharge Power - 2 Sec / 10 Sec
kW
50 / 45
46 / 38
Peak Regen Pulse Power (10 sec)
kW
30
25
Available Energy for CD (Charge Depleting) Mode, 10 kW
Rate
kWh
3.4
11.6
Available Energy for CS (Charge Sustaining) Mode
kWh
0.5
0.3
Minimum Round-trip Energy Efficiency (USABC HEV Cycle)
%
90
90
Cold cranking power at -30°C, 2 sec - 3 Pulses
kW
7
7
CD Life / Discharge Throughput
Cycles/MWh
5,000 / 17
5,000 / 58
CS HEV Cycle Life, 50 Wh Profile
Cycles
300,000
300,000
year
15
15
Maximum System Weight
kg
60
120
Maximum System Volume
Liter
40
80
•Characteristics at EOL (End of Life)
Reference Equivalent Electric Range
Calendar Life, 35°C
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Technology Development
Roadmap
Research Goals
Cost Goals
Specific Energy: 100 Wh/kg (by 2010)
150 Wh/kg (by 2015)
Phase 1: Materials
Development
Phase 2: Cell
Development
HEV:
PHEV:
Phase 3: Battery
Development
$20/kW (by 2010)
$250/kWh (by 2015)
Phase 4: Cost
Reduction
1 2 3
Commercialization
Long-term, exploratory
4
5
6
7
Intermediate term
8 9
Near market-ready
10 Commercialized
1.
2.
3.
4.
Li Metal Polymer
Li/Sulfur system
Li alloy/high V TMO system
Li titanate/Mn spinel
- Enerdel
5. Graphite/Mn spinel
- CPI/LG Chem
6. Graphite/Iron phosphate
- A123Systems
7. Graphite/Nickelate
- Johnson Controls - Saft
8. Ultracapacitors
- Nesscap, Maxwell
9. Low cost separators
- Celgard, UMT, AMS
10. NiMH
- Cobasys, Saft, Varta
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Program Elements
Vehicle
Technologies
USABC Activity
Advanced Technology
Development
 Assist battery developers to overcome
barriers for high power Li-ion batteries
 Innovative, cutting-edge long term
research to understand and solve life
and performance limitations of mid-term
technologies
Batteries for Advanced
Transportation
Technologies
Fundamental
Research Projects
 Cost-shared development activity with
industry leading to full battery systems
 Benchmark and assess existing and
candidate battery technologies
Basic Energy
Sciences
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Research Directions
 Interphase Studies
 Continue search for better membranes or glasses
 Continue search for the cause of high interfacial resistance
 What is the composition of the SEI, how might it change with aging, and
what should comprise an ideal and stable SEI?
 Electrolytes
 High voltage electrolytes (4.5 – 5 Volts)
 Solid polymer electrolytes
 What should a non-flammable electrolyte (with performance similar to
today’s materials) contain?
 Positive Electrode Material
 Next-generation olivine, layered, and spinel structures
 What new materials/structures should be considered for high capacity
positive materials (>250 mAh/g)?
 Negative Electrode Material
 Novel inter-metallic alloys and new binders
 Nanophase metal oxides
 How can the volume changes inherent in high-energy alloys be
accommodated or reduced?
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Conclusion
We look forward to continued collaboration
with our Basic Energy Sciences colleagues
to
 Discover new solutions to existing problems,
and
 Apply new discoveries in material and
chemical sciences that will result in major
breakthroughs.
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