Presented at the 1st International Conference on Advanced Lithium Batteries for Automotive Applications held Se

NREL is a national laboratory of the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy ope

Gi-Heon KimKandler SmithNational RenewabNREL/PR-540-44245

Multi-Scale Multi-Dimensionafor Better Cell Design and Management

1st International Conference on Advanced Lithium Batteries for 

Argonne, September 15–17, 2008
National Renewable Energy Laboratory 

“Requirements” are usually defined in a macroscale domain and terms.

Design of Materials

VoltageCapacityLattice stabilityKinetic barrierTransport property

Design of Electrode Architecture

Li transport path (local)Electrode surface areaDeformation & fatigueStructural stabilitySurface physics

Design of Electrodes Pairing and Lithium Transport

Electrodes selectionLi transportPorosity, tortuosityLayer thicknesses Load conditions

DCT

Requirements & Resolutions 

Multi-Scale Physics in Li-Ion 
National Renewable Energy Laboratory 

a) Quantum mechanical and molecular dynamic modb) Numerical modeling for addressing the impacts of 

electrode materials

c) 1D performance model capturing solid-state and e

dynamics

d) Cell-dimension 3D model for evaluating macrosco

a) b) c) d

Need a Multi-Scale Model?

Numerical approaches focusing on different length 
National Renewable Energy Laboratory 

Why macro-scale transport beco

Sub-electrode scale physicsKineticsLi diffusionIon transportHeat dissipation

Spat• Ele• Tem

Design of current and heat flow paths

Size Effect

Dimension

Surface Area / Volume

Spatial Difference

(gradient x distance)

Flux (gradient) Barrier (distance)

Dimension Increa
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Image source: www.dimec.unisa.it

Simulation

Domain

X

R

=

• Multi-scale physics from sub-micro-scale to batter• Difficulties in resolving microlayer structures in a c

Macro Grid 

+

To address

...

MultiScale 

MultiDimensional (MSM

Approach in the Present Stu
National Renewable Energy Laboratory 

tRXT ),,( 

tRXV ),,(

tRXSOC ),,(

tRXi ),,(

V

Adx QtRXQ

x

=

∫ i ),,(

NOTE:Selection of solution scheme for either grid system is independent of the other.

Image source: www.dimec.unisa.it

Detailed 

Structure

X

R

≈ Cell Dimension 

Transport Model

+

Solution Variables
National Renewable Energy Laboratory 

Previous Study

AABC 08, Tampa, May 2008

“Po

and 

cause excessive nand then deteriorshorten the life of 
National Renewable Energy Laboratory 

Analysis

Comparison with Experimental Res

Model Validation against JCS VL41

Macro-Scale Design Evaluation Ana

Impacts of Aspect Ratio of a Cylindr
National Renewable Energy Laboratory 

Analysis

Comparison with Experimental Res

Model Validation against JCS VL41

Macro-Scale Design Evaluation Ana

Impacts of Aspect Ratio of a Cylindr

The JCS VL41M cell was chosen as a candidate for • 1-D electrochemical model was previously validated vs. VL4• Thermal imaging experiments were recently run.• Future calorimeter test data will allow for further refinement & 
National Renewable Energy Laboratory 

Approach

1) 1-D Electrochemical Model Validation

• Measured current & temperature profiles used as inputs • Model predicts voltage & heat generation rate

2) Multi-Scale Multi-Dimensional (“MSMD”) Model V

• Utilized 3D thermal model results to extract thermal bou

• Measured surface temperature compared to model pred

surface temperature.

3) MSMD Model Predictions

• Multidimensional features 

JCS VL41M 

Thermal Imaging Test

Data 

used for 

model 

validation
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1) 1D Electrochemical Model Va

Measure

temperathermal inputs to electroc

Model vocompare• Error g

* Skin temthermocou

CD CS Rest

Test Pro5 chargecharge-sUSABC 
National Renewable Energy Laboratory 

Irreversible hpredicted by compares wusing measumodel open-

• Entropic henegligible anin the model

Qirr = Im

CD CS Rest

Test Profile:5 charge depletion cycles + 60 charge sustaining cycles per USAB

* More rigoroto be measur

1) 1D Electrochemical Model Va
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2) MSMD Model Validation

Assumption for Model Simplification

Extended Foil

Extended Foil 

Note: The schematics shown above do not represent ac
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2) MSMD Model Validation

• Complex thermal pathway was captured in 3D thermal mappropriate thermal boundary condition was evaluated for 

Retrieving information from 3D Thermal Model for 

IR Image 

100 A Geometric Cycle - Ste

- General system respondistributions at cell skins, is well predicted and revetransferred through the 3 
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2) MSMD Model Validation

Evaluating thermal boundary conditions at jelly-ro

Heat transfer coefficient at jelly-roll surfaces of the middle c

Area Weighted Averageshtop = 22.6 W/m

2

K

hside = 8.7 W/m

2

K

hbottom= 12.4 W/m

2

K

hinf = 8 W/m2K

hbottom

Axisymmet
National Renewable Energy Laboratory 

2) MSMD Model Validation

cp = 

Comparison with Measured Temperature

Measured can surface temperature and model-predicted jeagree reasonably well. Without an internally-instrumented directly validate the MSMD model’s jelly-roll temperature pr

CD CS R

1.4°C
National Renewable Energy Laboratory 

R

3) MSMD Model Prediction

• t = 1770 s• Tcan wall = 31.6°C

• Current = 409 A

Snapshots at the end of CHARGE DEPLETING cy

X

R

max(T) – min(T) = 1.4oC

R

X

R 

Temperature

Potential

Heat Transport

Electron Transport
National Renewable Energy Laboratory 

3) MSMD Model PredictionAh-throughput during CHARGE DEPLETING cycle

Ah-throughput imbalance during CD cycling (Ah/m

2 – 

+

• t = 1770 s• Tcan wall = 31.6°C

• Current = 409 A

Temperature at the end of CD cycles
National Renewable Energy Laboratory 

Analysis

Comparison with Experimental Res

Model Validation against JCS VL41

Macro-Scale Design Evaluation Ana

Impacts of Aspect Ratio of a Cylindr

The JCS VL41M cell was chosen as a candidate for • 1-D electrochemical model was previously validated vs. VL4• Thermal imaging experiments were recently run.• Future calorimeter test data will allow further refinement and 
National Renewable Energy Laboratory 

Aspect Ratio of Cylindrical 

U• 

PHEV10 application• US06 cycle discharges 3.4 

kWh in 12 minutes (~3C rate)

20 Ah cell• Well suited for PHEV10• BSF = 78 

→

Vnom

≈

290V

“Nominal”

“Large D” 
National Renewable Energy Laboratory 

Brief Look at “What H/D Ratio M

2

, ~

H i P foilloss

δ

ρ ⋅ ′′

2 ~

H i Vfoil

δ

ρ ⋅ ′′ Δ

H

W

Volume = const

H

D

H 

x W = const

+

-

e- 

Foil thicknesses Al: 20 μmCu: 15 μm

Voltage at Positive F

i“: current [A/m

2

ρ: resistivityδ: foil thickness
National Renewable Energy Laboratory 

10s Power Capability Comp

Large H

Nominal

Large D

40

110

90

60

50

100

80

70

120

30

10 20 30 40 50 

SOC 

Discharge Power (kW)

HPPC, B

• Large H design has acapability.

D[mm]: 28H[mm]: 350

D[mm]: 50H[mm]: 107

D[mm]: 115H[mm]: 20
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US06 CD Cycle x 2, Natural Con

Large H ctemperatlong elecresulting 

Foil heat • 15% - • 1.7% - • <0.1% 

Large H cinternal te
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Amp-hour

Throughput

Imbalance

Large Dia. Cell

-0.1% to +0.03%

Nom

-0.2% 

Large Height 

-1.2% to +2.9

US06 CD cycle

2.5%

2.0%

1.5%

1.0%

0.5%

0%

-0.5%

-1.0%

US06 CD Cycle x 2, Natural Con

(Ah/m

2 
National Renewable Energy Laboratory 

Summary

Nonuniform battery physics, which is more probab

cells, can cause unexpected performance and life delithium-ion batteries. 

A Multi-Scale Multi-Dimensional model was develo

investigating interaction between micro-scale electroand macro-scale transports using a multi-scale mod

The developed model will be used to provide bette

and help answer engineering questions about impro

cell operational strategy, cell management, and cell 

Engineering questions to be addressed in future works inc

What is the optimum form-factor and size of a cell?Where are good locations for tabs or current collectors?How different are measured parameters from their nonmeasWhere is the effective place for cooling? What should the heHow does the design of thermal and electrical paths impact usafety events, such as internal/external short and overcharge
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Acknowledgments

Vehicle Technologies Program at DOE

• Tien Duong• Dave HowellNREL Energy Storage Task• Ahmad Pesaran
National Renewable Energy Laboratory 

Thank you!
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Additional Slides
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Heat Transfer – 100 A Geometr

A

C

B

A

C

B

-20-10

0

102030405060708090

positiveterminal

Percentage of Heat Rejection [%] 

68.46

4.99

4.66

Percentage o

Percentage o

- Skin temperature of Cell C is low, because it is directly connected to the cable through the positive terminal. - There are inflows of heat through the positive thermals at 

Cell A and Cell B which are connected to the negative terminals of the neighbor cells.- Most heat is rejected through cell side surfaces. About 10% of heat is dissipated at bus bar surfaces. 12% runs away through cables.
National Renewable Energy Laboratory 

3) MSMD Model Prediction

Temperature Distribution after 30 sec 300 A 

Temperature Distribution after 20 min 100 A ge
National Renewable Energy Laboratory 

US06 CD Cycle x 2, Natural Con

Tmax-Tmin = 1.7°C

Tavg = 44.7°C

Tmax-Tmin 

Tavg = 45.5

Tmax-Tmin = 3

Tavg = 47.6°C

Temperature Distribution
National Renewable Energy Laboratory 

Integrated

Heat

Imbalance

20%15%

10%

5%

0%

-5%

Large Dia. Cell

-0.1% to +0.1%

No

-1.1

Large Height 

-9% to +21%

US06 CD cycle

US06 CD Cycle, Natural Convec
National Renewable Energy Laboratory 

Forced Convection

Natural Convection

(h = 

8 W/m

2 K)

Forced Air Conv

(h = 30 W/m

2 K

~ 5

oC in Large H and Large D format, ~2

oC in Nom
National Renewable Energy Laboratory 

Forced convection – negligible impact on generated

Integrated

Heat

Imbalance

20%15%

10%

5%

0%

-5%

Large Dia. Cell

Natural: -0.1% to +0.1%

Forced: -0.3% to +0.2%

No

Natural: 

Forced: 

Large Heigh

Natural: -9% t

Forced: -9% t

US06 CD cycle

Forced 

Convection

Forced Convec
National Renewable Energy Laboratory 

Despite additional thermal imbalance, fordoes not drastically change localized mat

Amp-hour

Throughput

Imbalance

Large Dia. Cell

Natural: -0.1% to +0.03%

Forced: -0.3% to 0.07%

Nom

Natural: -0

Forced: -

Large Height 

Natural: -1.2% to 

Forced: -1.3% to 

US06 CD cycle

2.5%

2.0%

1.5%

1.0%

0.5%

0%

-0.5%

-1.0%

Forced 

Convection

Forced Convec
National Renewable Energy Laboratory 

Comparison of natural and forceat t = 690 s of US06 cycle

Tavg (°C)

Tmax-Tmin (°C)

Natural 44.4 1.6Forced 40.9 4.1

Natural Forced 

Tav

Natural 4Forced 4

Large D

Large H

Nominal