NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.

Computer-Aided Engineering of 

Automotive Batteries

The 10th Advanced Automotive Battery Conference 

Orlando, Florida 

May 19-21, 2010

Gi-Heon Kim 

Kandler Smith

Ahmad Pesaran

National Renewable Energy Laboratory 

David Howell*

U.S. Department of Energy

NREL/PR-540-48145

Funded by Energy Storage R&D (David Howell), 

Vehicle Technologies Program U.S. Department of Energy
National Renewable Energy Laboratory Innovation for Our Energy Future

Introduction – Battery CAE

• Computer-aided engineering (CAE) is a proven pathway, especially in 

automotive industry, to

• Improve performance by resolving relevant physics in complex systems 

• Shorten product development design cycle and thus reduce cost

• Provide an efficient manner for evaluating parameters for robust designs

• Most battery CAE models could be enhanced 

• Academic models include relevant physics details, but neglect engineering 

complexities 

• Industry models include relevant macroscopic geometry and system 

conditions, but use too much simplification in fundamental physics

• DOE- and private-industry-funded projects have demonstrated the value 

of battery CAE 

• Most in-house custom model codes, however, require expert-users

• Battery CAE capabilities need to be transferred to industry

• In time to impact the transition toward sustainable electric mobility

• Reduce the process of design, build, test, break, redesign, rebuild, retest,...

2
Multi-Scale Physics in Li-Ion Battery

Various physics interact across wide range of length and time scales

National Renewable Energy Laboratory 3 Innovation for Our Energy Future

Design of Materials Design of 

Electrode Architecture

Design of Transport at

Electrode/Electrolyte

Design of Electron &

Heat Transport Operation & Management

Present industry needs z 

• Performance & Life Models: Coupling electrode-level 

performance/life with cell/pack-level heat/current transport

• Safety Models: Coupling electrode-level chemical 

reactivity and cell/pack-level heat transport

• Need to include both science and engineering

Active research areas

•First Principals Material Evaluation

•Electrode Architecture Design
National Renewable Energy Laboratory Innovation for Our Energy Future

NREL Battery Modeling Portfolio

(diverse, but not integrated )

4

Model Length Scale Geometry Physics / Application

Vehicle/component 

(PSAT/ANL & Advisor/NREL)

Lumped • Drivetrain power balance / Drive cycle

• Battery usage & requirements

• Control strategy design

Battery cost Lumped • Empirical 

• System cost ($/kW, $/kWh)

Battery life Lumped • Empirical 

• Life prediction (t,Ncyc,T,ΔDOD,SOC) 

Equivalent circuit

(e.g. PNGV, FreedomCar)

Thermal/electrical 

network

• Electrical & thermal

• Performance, design, safety evaluation

Electro-thermal (FEA) 

& fluid-dynamics (CFD)

1-D, 2-D, & 3-D • Electrical, thermal & fluid flow

• Performance, detailed cooling design

• Commercial software (restrictive assumptions)

Electrochemicalthermal (“MSMD”)

1-D, 2-D & 3-D • Electrochemical, electrical & thermal

• Performance, design

Electrochemicalthermal-degradation

(“MSMD-life”)

1-D, 2-D & 3-D • Electrochemical, electrical & thermal

• Cycling- & thermal-induced degradation

• Performance, design, life prediction

Thermal abuse

reaction kinetics

Thermal network, 

2-D & 3-D

• Chemical & thermal

• Safety evaluation

Internal short circuit 3-D • Chemical, electrical, electrochem. & thermal

• Safety evaluation

Molecular dynamics 3-D • Atomic & molecular interactions

• Material design

pm --- nm --- μm --- mm ---- m
Battery CAE : What Should One Expect?

National Renewable Energy Laboratory 5 Innovation for Our Energy Future

• Multi-scale Physics Interaction: Integrate different 

scale battery physics in computationally efficient 

manner

• Flexibility: Provide a modularized multi-physics platform 

– Enable user choice from multiple submodel options 

with various physical/computational complexity

• Expandability: Provide an expandable framework to 

“add new physics of interest” or to “drop physics of 

insignificance/indifference” 

• Validation and Verification: The correct equations are 

solved and they are solved accurately
Design of Materials

Design of 

Electrode Architecture

Design of Transport at

Electrode/Electrolyte

Design of Electron &

Heat Transport Operation & Management

LBNL, MIT, ANL 

First Principles , 

U of Michigan

Meso-Scale Model

UC Berkeley

Dualfoil, 1D electrochem.

NREL, USC, Battery Design

1D, 2D, 3D, multi-scale electrochem.

ANSYS/CD-adapco

CAD, FEA, CFD Solvers

ANL, NREL, AVL

Vehicle Simulator

Length-Scale Mapping for 

Li-ion Battery Models 

(Examples and not a complete list)

National Renewable Energy Laboratory 6 Innovation for Our Energy Future

INL

Electrolyte models 
Charge Conservation

r

η = (φs −φe )−U

Example 

Electrode-Scale Performance Model

(k T ) q

t

T

c p = ∇⋅ ∇ + ′′′ ∂

∂

ρ

• Pioneered by Newman’s group (Doyle, Fuller, 

and Newman 1993) – Dualfoil 

(cchem.berkeley.edu/jsngrp/fortran_files/Intro_Dualfoil5.pdf)

• Captures lithium diffusion dynamics and charge 

transfer kinetics – porous media

• Predicts current/voltage response of a battery

• Provides design guide for thermodynamics, 

kinetics, and transport across electrodes

e e

eff

e e D

eff

s s

eff

s e

Li c

T

U

q j φ φ U T  +σ ∇φ ⋅∇φ +κ ∇φ ⋅∇φ +κ ∇ ⋅∇φ 

 





∂

∂ ′′′ = − − + ln

Charge Transfer Kinetics at Reaction Sites

Species Conservation

Energy Conservation • Difficult to resolve heat and electron current 

transport in large cell systems

National Renewable Energy Laboratory 7 Innovation for Our Energy Future
National Renewable Energy Laboratory Innovation for Our Energy Future

Extending Newman’s model to Thermal-EChem 3D 

NREL’s Multi-Scale Multi-Dimensional (Domain) Model Approach

8
Example Results of Battery Modeling

Multi-Physics Interaction

National Renewable Energy Laboratory 9 Innovation for Our Energy Future

Comparison of two 40 Ah 

flat cell designs

2 min 5C discharge

working potential working potential

electrochemical

current production

electrochemical

current production

Larger over-potential 

promotes faster discharge 

reaction

Converging current 

causes higher potential 

drop along the collectors
Example Results of Battery Modeling

Multi-Physics Interaction

National Renewable Energy Laboratory 10 Innovation for Our Energy Future

Comparison of two 40 Ah 

flat cell designs

2 min 5C discharge

working potential working potential

electrochemical

current production

temperature temperature

electrochemical

current production

High temperature 

promotes faster 

electrochemical reaction

Higher localized reaction 

causes more heat 

generation

Larger over-potential 

promotes faster discharge 

reaction

Converging current 

causes higher potential 

drop along the collectors
Example Results of Battery Modeling

Multi-Physics Interaction

National Renewable Energy Laboratory 11 Innovation for Our Energy Future

Comparison of two 40 Ah 

flat cell designs

2 min 5C discharge

working potential working potential

electrochemical

current production

temperature temperature

soc soc

electrochemical

current production

High temperature 

promotes faster 

electrochemical reaction

Higher localized reaction 

causes more heat 

generation

Larger over-potential 

promotes faster discharge 

reaction

Converging current 

causes higher potential 

drop along the collectors
Example Results of Battery Modeling

Multi-Physics Interaction

National Renewable Energy Laboratory 12 Innovation for Our Energy Future

Comparison of two 40 Ah 

flat cell designs

This cell is cycled 

more uniformly, can 

therefore use less 

active material ($) 

and has longer life.

2 min 5C discharge

working potential working potential

electrochemical

current production

temperature temperature

soc soc

electrochemical

current production

High temperature 

promotes faster 

electrochemical reaction

Higher localized reaction 

causes more heat 

generation

Larger over-potential 

promotes faster discharge 

reaction

Converging current 

causes higher potential 

drop along the collectors
Virtual 

Battery Design

Vehicle Simulator

-10

0

10

20

30

40

50

60

70

80

90

0 100 200 300 400 500 600

Time (s)

Vehicle Speed

Vehicle Design Vehicle Driving Profile

Virtual

0 10 20 30 40 50 60

-600

-400

-200

0

200

400

600

800

Battery Power Profile

Multi-Scale

Multi-Dimensional 

Li-ion Battery Model

Battery Responses Feedback

Embedded 

Battery Model

National Renewable Energy Laboratory 13 Innovation for Our Energy Future

Virtual Design Evaluation 

Integrated Battery – Vehicle Approach

Charge sustaining

Charge depleting

Combination

Charging
Need to Develop Modular Plug-andPlay Modeling Design Concepts
National Renewable Energy Laboratory Innovation for Our Energy Future

Future Plans – Battery CAE

ξ1

ξ2

ξ3

x1

x2

x3

X1

X2

X3

3D 1D 3D

ξ particle domain dimension x electrode domain dimension X cell domain dimension

3D

pack/system domain dimension

Future Development

XX 

• Integrating various models in one single platform for industry to use

• Bottom-up model validation and demonstration study

• Enhancing physics models

• Enhancing solver capability & solution schemes

15
A New Activity – CAE for Batteries

• In the last several years, DOE’s Vehicle Energy Storage 

Program has been funding battery modeling as part of its

– Exploratory Battery Activity (BATT)

– Applied Battery Research Activity (ABR)

– Battery Development Activity 

• DOE has been evaluating approaches to integrate these 

battery modeling activities and make them more accessible 

as design tools for industry

• In April 2010, DOE initiated implementing the ComputerAided Engineering for Electric Drive Vehicle Batteries 

(CAEBAT) activity

– Objective is to incorporate existing and new models into software 

battery modeling suites/tools 

– Goal is to shorten design cycle and optimize batteries (cells and 

packs) for improved thermal uniformity, safety, long life, low cost

National Renewable Energy Laboratory 16 Innovation for Our Energy Future
CAEBAT Operating Structure and Plans 

• Operate similarly to BATT and ABR activities 

• Include several National Laboratories

• One Lab coordinating the activities for DOE (NREL for CAEBAT)

• Include competitive collaborations with universities and 

industry (cell developers, pack integrators, vehicle makers, 

and software venders)

• Include structured tasks and subtasks dealing with 

materials/components, cells, packs, and open software 

architecture 

• Seek collaboration with federal, state, and private 

organizations for leveraging resources

• Conduct annual planning, progress, and review meetings

National Renewable Energy Laboratory 17 Innovation for Our Energy Future
Elements of CAEBAT Structure

National Renewable Energy Laboratory 18 Innovation for Our Energy Future

CAEBAT Program 
CAEBAT

Overall Program Coordinator

Task 1

Open Architecture

Software

(New Activity)

Task 2

Battery PackLevel Models

(Continued Activity)

Task 4

Electrode/ComponentLevel Models

(Continued Activity)

Major Activities and Responsibilities

Task 3

Cell-Level 

Models

(Continued Activity)

 Industry 

Support

Industry and 

University Support

Through RFP

Industry and 

University Support

Through RFP

Lab Support

Industry Support

University

Material Level Models

Developed under BATT/ABR Activities

Work in progress

CAEBAT Program
Planned Activities – CAEBAT Program

• Interact with other, National Labs, industry, and 

universities 

• Develop detailed description of tasks and overall 

program plan

• Conduct model development and integration in 

National Labs and later by industry and universities

• Issue Request for Proposals (RFP) in July, receive 

proposals, review them, and select awardees by end 

of September

– Multi-year, multi-partner projects 

• More to come...................

National Renewable Energy Laboratory 20 Innovation for Our Energy Future