A High-Performance PHEV Battery Pack
PI: Mohamed Alamgir and Geun-Chang Chung
LG Chem Power / LG Chem
May 16, 2012 Project ID: ES002
“This presentation does not contain any proprietary, confidential, or otherwise restricted information”
LG Electronics LG Display LG Innotek LG Siltron … 9 Companies
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Established Lucky Chemical Industrial Corp. in 1947
Changed its name from Lucky Gold Star to LG in 1995
LG Chem LG Hausys LG Healthcare LG Life Sciences … 13 Companies
Chemical
Sales (2011) – $124B Employees – 210,000
LG Group at a Glance
ABS/EP
NCC/Polyolefin
PVC/Rubber
Acrylate
LCD Polarizer
LCD Glass
OLED Materials
Color Filter
Lithium-Ion Batteries for
- Mobile Phone, Laptop, Power Tool
- Hybrid & Electric Vehicles
- ESS
Energy
Solution(10%)
Petro- chemicals
(75%)
IT & Electronics
Materials (15%)
$ 19.5 B (2011) IT &
Electronics Materials
(17%)
Petro- chemicals
(23%)
Energy
Solution(60%)
Revenue R&D Expense
Energy Solution Petrochemicals IT & Electronics Materials
LG Chem at a glance
Battery Pack Concepts, Design and Prototype Builds
Battery Management Systems Sales and Customer Support
LGCPI
$300M+ investment with ARRA funding
Groundbreaking: Summer 2010
Production begins in 2012
LGCMI
Troy, MI Sales & Pack R&D
Holland, MI Cell Manufacturing
Cell Structure: Unique Stack- and-Fold Design
Positive terminal
Negative terminal
Lead film (insulation tape)
Stack and Folded cell
Bi-cell Laminated film
SRSTM
Stacking of Plates & Folding
SRSTM provides superior abuse-tolerance By improved mechanical and thermal stability By preventing internal short circuit By providing lower shrinkage
Nano scale Ceramic Particles
Micro porous Polyolefin film
Proprietary Safety Reinforcing Separator (SRSTM)
Significantly higher puncture strength than conventional separator
• Project Start: April 1, 2011 • Project End: March 31, 2013 • Percent complete: 50%
• Total project funding: $9.6M • DOE share: $4.8M • Contractor share: $4.8M • Funding for FY11: $3.2M
Timeline
Budget
Barriers
• LG Chem, INL, SNL, NREL
• Project lead: LGCPI
Partners
Overview of Current Program
• Specific Energy and Power
• Cycle- and Calendar-life
• Cell Cost goal of <$200/kWh
• Efficient Refrigerant-to-Air cooling system
Develop a cell suitable for use in the PHEV-40 Mile program using next generation, high capacity Mn-rich cathode materials.
A key goal of the program is to lower the pack cost to close to the $3400 target.
Optimize the Refrigerant-to-Air cooling system we have developed in our previous program with respect to mass, volume, cost and power demand.
Deliver cells and battery packs to USABC for testing.
Objectives
PHEV 40-Mile Battery Pack Goals
Characteristics at EOL Units
Requirements for
40-MileProgram
Reference Equivalent Electric Range Miles 40Peak Pulse Discharge Power, 2 Sec kW 46Peak Pulse Discharge Power, 10 Sec kW 38Peak Regen Pulse Power, 10 Sec kW 25Available Energy, CD4 mode, 10kW rate kWh 11.6
Available Energy, CS4 mode kWh 0.3
Minimum round-trip Energy Efficiency5 % 90Cold Cranking Power at -30°C, 2 sec / 3 pulses (2-10-2-10 2)
kW 7
Cycles; 5000
MWh 58CS HEV Cycle Life, 50Wh Profile Cycles 300,000Calendar life at 35°C Years 15Maximum System Weight Kg 120Maximum System Volume Liters 80Maximum Operating Voltage Vdc 400Minimum Operating Voltage Vdc >0.55VmaxMaximum Self-Discharge Wh/da
y50
1.4
(120V/15A)Maximum System Production Price @100k units/year US$ $3,400
CD Life / Discharge throughput
System Recharge Rate at 30°C kW
Study high capacity, Mn-rich, layered-layered cathode materials from multiple vendors.
Characterize and Improve the performance, life and abuse-tolerance of Mn-rich cathode materials.
Optimize, fabricate and deliver battery packs based on Refrigerant-to-Air cooling system we have developed in our earlier USABC Program.
Approach/Strategy
Mn-rich cathode materials from two vendors have been evaluated.
Built cells with careful control of various cell fabrication parameters/processes such as electrode formulations, formation protocol etc to identify conditions optimum for performance and life.
Studied the effect of operational voltage ranges on energy, power and life.
Studied the effect of electrolyte additive on life.
Technical Accomplishments/Results
Our 1st generation Refrigerant-to-Air pack has been redesigned and is being optimized with respect to Weight, Volume, Power demand.
Cell- and Module level thermal studies have been
carried out to examine the efficacy of this cooling concept.
First prototype packs have now been built and are being evaluated for cooling efficiency.
Technical Accomplishments/Results
Baseline studies with Mn-rich cathodes show capacities as high as ~ 250 mAh/g at RT.
Strong dependence on rate.
0 50 100 150 200 250 3002.5
3.0
3.5
4.0
4.5
Volta
ge (V
)
Discharge capacity (mAh/g)
0.1C 1C
0 50 100 150 200 250 3002.5
3.0
3.5
4.0
4.5
Volta
ge (V
)Discharge capacity (mAh/g)
0.1C 1C
Sample A Sample B
Results- continued……
Rapid increase in DC resistance at low SOCs. This can limit the usable SOC range for PHEV
applications.
Results- continued……
0 10 20 30 40 50 60 70 80 90 1000.0
2.0
4.0
6.0
8.0
Resi
stan
ce (m
ohm
)
SOC (%)
Discharge resistance Regen resistance
Co Mn Ni 24 ppm 145 ppm 19 ppm
High voltage operation results in severe Mn dissolution in regular electrolyte.
Need to identify suitable electrolyte
Results- continued……
0 20 40 60 80 100 120 140 1600.0
20.0
40.0
60.0
80.0
100.0
25oC 4.5V~2.0V 1C/2C cycle
Norm
aliz
ed c
apac
ity (%
)
Cycle
Max charge voltage has a strong influence on cycle-life.
45oC 1C/2C cycle
Results- continued……
0 50 100 150 200 250 300 350 400 4500
20
40
60
80
100
4.5V4.45V 4.35V
4.4V
4.1V
Norm
aliz
ed c
apac
ity (%
)
Cycle
4.5V 4.45V 4.4V 4.35V 4.24V 4.1V
4.24V
Discharge cut-off voltage also has significant effect on cycle-life.
Results- continued……
0 50 100 150 200 250 300 350 4000
20
40
60
80
100No
rmali
zed
capa
city (
%)
Cycle
4.4V~2.0V 4.4V~3.18V
45oC 1C/2C cycle
Electrolyte additives enhance cycle-life.
45oC 4.5V~2.0V 1C/2C cycle
0 20 40 60 80 100 120 140 160 180 2000
1020
30
4050
60
7080
90
100
Nor
mal
ized
cap
acity
(%)
Cycles
Ref. Ref. + Add#5 Ref. + Add#7 Ref. + Add#5 & Add#7
Results- continued……
Requires refrigerant loop; but: Avoids coolant fill and maintenance, obviates need for
complex coolant manifolds and risks of leaking.
Phase I- Two thermal zones: Refrigerated compartment (cells, evaporator, fan) Ambient compartment (controls, compressor, condenser,
fan)
Results: Refrigerant Cooling System
Thermal
Results: Phase II Cooling System- integrated design
Electronics
Cells
A refrigerant loop is used to cool the cold-plate inside the battery pack which in turn is attached to fins sandwiched between the cells.
24.7
25.8
26.326.5
26.3 26.426.1
25.9
25.1
20.0
21.0
22.0
23.0
24.0
25.0
26.0
27.0
28.0
29.0
30.0
CT1 CT2-3 CT4-5 CT6-7 CT8-9 CT10-11 CT12-13 CT14-15 CT16
Tem
pera
ture
(C°)
Thermocouple Name
10Nov2011 USABC Module Thermal Testing Test 4--Repeated US06 Drive Cycles (derated) from 90%-20%SOC, Module at Room Temp, 15°C cold plate, 1mm Al fin - 90deg bend-
TC Cell Temps at Worst dT(1.8C°)
Results: Cooling System- Module Level Testing
US06 Drive Profile SOC range = 90- 20% 25oC, Cold-plate at 15oC Max ∆T among cells : ~2o C
Efficient cooling- satisfies target
21.2
21.1
21.0
20.9
20.8
21.0 21.0
20.9
21.1
20.0
20.2
20.4
20.6
20.8
21.0
21.2
21.4
21.6
21.8
22.0
CT1 CT2-3 CT4-5 CT6-7 CT8-9 CT10-11 CT12-13 CT14-15 CT16
Tem
pera
ture
(C°)
Thermocouple Name
14Nov2011 USABC Module Thermal Testing Test 5--Repeated UDDS Highway Drive Cycle (5kW rms) from 90-20%SOC, room temp ambient, 15°C cold plate, 1mm Al fin
with 89* bend -TC Cell Temps at Worst dT (0.4C°)
Results: Cooling System- Module Level Testing UDDS Drive Profile SOC range = 90- 20% 25oC, Cold-plate at 15oC Max ∆T among cells : ~0.5o C
Future Work
Studies to improve power and life will include, among others
Surface-modified cathodes Different electrolyte compositions/additives.
Delivery of cells to National Labs for evaluation with
improved power and life.
Testing of prototype packs under various heat-loads using different driving profiles and additional optimization of the thermal system.
Delivery of packs to National Labs.
Project Start: Jan 1, 2008 Project End: March 31, 2010 Percent complete: 100
Cycle-life Calendar-life Cold-Cranking Power Efficient/reliable
thermal management system
• Total project funding: $12.7M
Timeline
Budget
Barriers Addressed
• LG Chem, INL, SNL, NREL
• Project lead: LGCPI
Partners
Overview of Last PHEV Program
Project Start: Jan 1, 2008 Project End: March 31, 2010
Total project funding: $12.7M
Timeline
Budget
Cell/ Approach
• Cycle-life improved significantly: 5000 cycles
• Calendar-life needs additional improvement
Key Results
Highlights of Past PHEV Program
Barriers addressed
Cycle-life Calendar-life Abuse-tolerance
• Oxide-blend cathode/graphite
• Refrigerant-to-air cooling system
Project Start: Sep 1, 2006 Project End: Feb 29, 2008
Total project funding: $6.3M
Timeline
Budget
Cell/ Approach
• Cycle-life improved significantly: > 550k cycles
• Calendar-life: > 10 yrs • Excellent abuse-
tolerance
Key Results
Highlights of Past HEV Program
Barriers addressed
Cycle-life Calendar-life Cold-Cranking Power
• Spinel/Hard-Carbon • Approaches used: coatings, dopants, use of electrolyte additives
OEM Vehicle Cell GM Chevy Volt PHEV Ford Focus BEV PHEV Hyundai Sonata
Hybrid HEV
Use of LGC’s Cells in Production Vehicles
These cells benefitted directly from the development programs LGCPI had with USABC.
LGCPI team (Paul Laurain, Satish Ketkar, Jongmoon Yoon and Kwangho Yoo)
LG Chem team (Geun-Chang Chung, Song-Taek Oh, Jaepil Lee)
USABC for their financial and technical support in course of these programs.
Paul Groshek- Program Manager
INL (Jeff Belt), NREL (Ahmad Pesaran, Kandler Smith), LBNL (Vince Battaglia) and SNL (Chris Orendorff) for invaluable technical support
Acknowledgements
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