A High-Performance PHEV Battery Pack

PI: Mohamed Alamgir and Geun-Chang Chung

LG Chem Power / LG Chem

May 13, 2013 Project ID: ES002

“This presentation does not contain any proprietary, confidential, or otherwise restricted information”

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

IT & Electronics

Materials $ 22 B (2012) IT &

Electronics Materials

Petro- chemicals

Energy

Solution

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 2013

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: December 31, 2013 • Percent complete: 79%

• Total project funding: $9.6M • DOE share: $4.8M • Contractor share: $4.8M • Funding for FY12: $2.0M

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.

Improve upon 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- Fin indirect cooling system.

Approach/Strategy

Mn-rich cathode materials from multiple sources have been evaluated.

Built cells with 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. Surface coatings on cathode particles considerably

improve the durability of Mn-rich cells.

Technical Accomplishments/Results

1st Gen cells (24Ah) were built and sent to National Labs for evaluation. Results showed the need for significant improvement in life.

Battery packs using refrigerant-to- fin indirect cooling system have been designed and optimized with respect to Volume Weight, Robustness, and Power demand.

Testing of prototype packs under various heat-loads using different

driving profiles have been carried out. Data show good efficacy of this cooling system.

Prototype packs have been built and delivered to National Labs for evaluating their 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

Charging to voltages such as 4.5V to access higher capacity leads to significant gas evolution. This causes swelling and premature cell failure.

This gas generation necessitates considerable adjustment to cell processing conditions, such as formation.

Results- continued……

Co Mn Ni 24 ppm 145 ppm 19 ppm

High voltage operation results in severe Mn dissolution in regular 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.

Results- continued……

0 100 200 300 400 5000.0

0.2

0.4

0.6

0.8

1.0

1.2

67%72%

28% 4.35V-2.5V DOD100 4.5V-2.5V DOD80 4.5V-2.5V DOD100

Nor

mal

ized

Cap

acity

Cycle

Discharge cut-off voltage 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 appear to 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……

Improved separator helps to enhance cycle-life.

45oC 4.45V~2.5V 0.5C/1C cycle

Results- continued……

0 20 40 60 80 100 120 140 1600.0

6065707580859095

100105110

Reference New Separator

Cyc

le R

eten

tion

(%)

Cycle Number

Surface coating enhances cycle-life.

Results- continued……

0 20 40 60 80 10070

80

90

100

ALD Mn-rich (mono cell) Bare Mn-rich (mono cell)

Nor

mal

ized

Cap

acity

Cycle

25oC 4.35V- 2.5V 0.5C/1C cycle

Surface Coated - Red Bare- Black

Surface coating reduces resistance rise during cycling.

Results- Effect of Surface coating…

0 20 40 60 80 100 120 1400

20

40

60

80

100

120

140

HV Formation/SOC 100 EIS Measurement

Z''

Z'

Pristine Formation (R3 = 86.7 Ωcm-2, R4 = 34.8 Ωcm-2) 2ALD-Pristine Formation (R3 = 103 Ωcm-2) 5ALD-Pristine Formation

0 20 40 60 80 100 120 1400

20

40

60

80

100

120

140

50 Cycle/SOC 100 EIS Measurement

Pristine Formation (R3 = 71.4 Ωcm-2, R4 = 58.0 Ωcm-2) 2ALD-Pristine Formation (R3 = 48.8 Ωcm-2, R4 = 12.1 Ωcm

Z''

Z'

Bare- Blue Coating I- Red Coating II- Red II

Bare- Blue Coating I- Red

• Amount of Al2O3 secondary ion (AlO-, AlO2-) after cycling was decreased, while that

of AlF3 secondary ion (AlF2-, AlF4

-) was increased. - Al2O3 was changed to AlF3 by the reaction of Al2O3 with HF.

• AlF3 is known to show lower resistance to Li ion diffusion than Al2O3.

Results- Effect of Surface coating…

Before Cycling After Cycling

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 at the bottom of the battery pack which, in turn, is attached to solid fins located between the cells.

Picture of a Pack delivered to USABC

Results: Thermal and Electrical Compartments

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

Results: Cooling System- Pack Level Testing UDDS Drive Profile SOC range = 90- 20% 25oC, Cold-plate at 15oC Max ∆T among cells : ~0.5o C

Results: Cooling System- Pack 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 develop Gen 2 of cells having improved life and performance are currently underway. These include:

Use surface-modified cathodes Use of new electrolyte

compositions/additives.

Delivery of Gen 2 cells to National Labs for evaluation with improved power and life.

Delivery of final packs to National Labs.

OEM Vehicle GM Chevy Volt Ford Focus BEV Hyundai Sonata Hybrid Volvo XC 60 Renault Zoe

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, Hoejin Ha, 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 valuable technical support

Acknowledgements