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.

Energy Storage R&D

Computer-Aided Engineering for Electric 

Drive Vehicle Batteries (CAEBAT)

PI: Ahmad A. Pesaran, Ph.D.

Contributors: Gi-Heon Kim, Kandler Smith, 

Shriram Santhanagopalan, and Kyu-Jin Lee

National Renewable Energy Laboratory

Golden, Colorado

Presented at the 2011 U.S. DOE Hydrogen 

Program and Vehicle Technologies Program 

Annual Merit Review & Peer Evaluation Meeting 

May 9–13, 2011, Arlington, Virginia 

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

Project ID: ES099 

NREL/PR-5400-50914
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Overview

• Project start date: April 2010

• Project end date: Sept 2014

• Percent complete: 15%

• Cost and life

• Performance and safety

• Slow prototype-driven design cycles 

for materials, cells and packs

• Lack of validated battery computeraided engineering tools suitable for 

non-expert use

2

• Funding received in 

─ FY10: $3.5M ($3.0M for 

subcontracts)

─ FY11: expected $3.5M ($2.5M for 

subcontracts)

Timeline

Budget

Barriers – Batteries 

Partners

• ORNL

• LBNL

• ANL

• SNL

• INL

• LLNL

• Colorado School 

of Mines

Funding provided by Dave Howell, Office of Vehicle Technologies (VT).

Activity managed by Brian Cunningham, Vehicle Technologies Program.

This presentation covers two related topics: CAEBAT Project 

and NREL battery modeling work under CAEBAT 
NATIONAL RENEWABLE ENERGY LABORATORY

Relevance – Need for Better Design Tools

• Computer-aided engineering (CAE) tools are widely used in 

many industries to speed up the product development cycle 

and reduce the number of build-and-break steps.

• In fact, use of CAE tools has enabled automakers to reduce 

product development cost and time while improving the safety, 

comfort, and durability of the components and the vehicles 

they produce. 

• However, there are no mature CAE tools for the design and 

commercial development of electric drive vehicle batteries.

• Although there are a number of battery models in academia, 

national labs, and industry, they either 

– Include relevant physics details, but neglect engineering complexities, or 

– Include relevant macroscopic geometry and system conditions, but use 

too many simplifications in fundamental physics

• There are a number of custom battery codes available; 

however, they all require expert users.

3
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• Battery CAE capabilities 

need to be further 

developed to accelerate

the development of 

batteries. 

• In previous years, under 

DOE funding, national 

laboratories and universities 

have developed several 

tools for electrothermal, electrochemical, and abuse reaction modeling 

of lithium-ion batteries.

• The concern has been that they were not all integrated and additional 

tools were needed. 

• In April of 2010, the DOE VT Energy Storage Program initiated the multiyear CAEBAT activity to develop design tools and an open architecture 

software framework that will enable disparate models to interface with 

each other.

Computer Aided Engineering for 

Electric Drive Vehicle Batteries (CAEBAT) Relevance 

Battery Pack 

Level Models

Performance

Electrochemical & 

Material Stress Material Stress

Current & Heat 

Transport

Electrode

Level Models

Cell

Level Models

Material

Level Models

Fluid Dynamics

First Principles

Power Demand

 

 

 

 

 

Source: VARTA

 

Battery Pack 

Design Software

4
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Objectives – DOE CAEBAT Program

5

• The objective of CAEBAT is to incorporate existing and new 

models into design suites/tools with the goal of shortening 

design cycles and optimizing batteries (cells and packs) for 

improved performance, safety, long life, and low cost. 

– The software suite will include material properties, electrode design, 

pack design for thermal management purposes, load profiles, and 

aging data as input, and could greatly speed up the design of new 

batteries and provide critical guidance to developers.

Relevance 

CAEBAT

Overall Program

Element 4

Open Architecture

Software

(New Activity)

Element 3

Battery Pack 

Level Models

(Continued Activity)

Element 1

Electrode/Component

Level Models

(Continued Activity)

Element 2

Cell

Level Models

(Continued Activity)
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Objectives – NREL CAEBAT Tasks

6

• As project coordinator, NREL supports DOE in establishing the 

CAEBAT programmatic activities and objectives.

– Provide input/documents for the CAEBAT project plan

– Coordinate activities among national laboratories

– Support industry and universities through a competitive process to develop 

battery CAE software tools

• Enhance and further develop NREL’s existing electrochemical, 

thermal, abuse reaction, and internal short circuit models for use 

by CAEBAT participants 

Model Length Scale Geometry Physics / Application

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

μm --- mm ---- m

Relevance 
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List of NREL Milestones 

7

Title Due Date Status

Draft Scope of Work for the CAEBAT 

program

June 2010 Completed

Issue Request for Proposals (RFP), 

review proposals and select industry 

awardees

December 2010 Completed

Negotiate and place subcontracts with 

CAEBAT RFP awardees 

June 2011

(Rescheduled)

On Track

Progress review on the work for the 

CAEBAT-NREL program

July 2011

(Rescheduled)

On Track 
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Approach/Strategy

8

• Based on DOE’s guidance, work with battery community & 

stakeholders (battery developers, car manufacturers, national 

laboratories, universities, software companies, etc.) to further 

refine the scope of the CAEBAT activity:

– Interact with other national laboratories to understand the capability of 

existing battery models and other computational capabilities. 

– Interact with industry and universities to understand the scope of their 

capabilities and eventual needs. 

– Provide input/documents to DOE for defining the CAEBAT project 

plan.

• Through competitive process, solicit cost-shared proposals 

from the industry and identify teams to develop battery CAE 

software tools.

• Perform in-house R&D to enhance and further develop NREL’s 

existing electrochemical, thermal, abuse reaction, and internal 

short circuit models for use by CAEBAT participants. 
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Overall CAEBAT Project

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Physics of Li-Ion Battery Systems in Different Length 

Scales

Li diffusion in solid phase

Interface physics

Particle deformation & fatigue

Structural stability

Charge balance and transport

Electrical network in composite 

electrodes

Li transport in electrolyte phase

Electronic potential &

current distribution

Heat generation and transfer

Electrolyte wetting

Pressure distribution

Atomic Scale

Particle Scale

Electrode Scale Cell Scale

System Scale

System operating conditions

Environmental conditions

Control strategy

Module Scale

Thermal/electrical

inter-cell configuration

Thermal management

Safety control

Thermodynamic properties

Lattice stability

Material-level kinetic barrier

Transport properties

Technical Accomplishments/Progress 

10

P

Active research Present industry needs 

With input from stakeholders, we identified various physics across a wide range of 

length and time scales that must be addressed, particularly at the pack/vehicle scale.

Accomplishments 
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Identified Community’s Expectation for Battery CAE Tools

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• Address Multi-Scale Physics Interactions: Integrate different 

scale battery physics in a computationally efficient manner

• Flexible: Provide a modularized multi-physics platform to enable 

user the choice from multiple sub-model options with various 

physical/computational complexities

• Expandable: Provide an expandable framework to “add new 

physics of interest” or to “drop physics of low significance or 

indifference” 

• Validated: Ensure that the correct equations are solved by 

performing carefully designed experiments

• Verified: The equations are solved accurately 

Accomplishments 
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Interacted with Six Other National Laboratories 

12

• Battery modeling experts from Argonne National Lab 

(ANL), Sandia National Lab (SNL), Idaho National 

Lab (INL), and Oak Ridge National Lab (ORNL) 

visited NREL 

• NREL battery researchers visited Lawrence Berkeley 

National Lab (LBNL), Lawrence Livermore National 

Lab (LLNL), and ORNL

• The capabilities and potential roles for each lab were 

identified

• Each lab provided input for the CAEBAT project 

planning document

• Based on DOE’s guidance:

– ORNL was funded in FY10 and FY11 to lead Element 4 to 

develop an open architecture software 

– Other labs were directed to continue any battery modeling 

work under their existing Advanced Battery Research 

(ABR) and Batteries for Advanced Transportation 

Technologies (BATT) Programs 

Accomplishments 
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Updated DOE CAEBAT Program Elements

13

Industry and University 

Collaborations through RFP

Accomplishments 

Assignments for Coordination

• Overall activity: NREL

• Element 1: LBNL

• Element 2: NREL

• Element 3: NREL

• Element 4: ORNL

Material-Level Models

Developed under BATT and 

ABR Programs
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Initiated Collaboration with Industry

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Accomplishments 

• Introduced the CAEBAT program at battery conferences and meetings 

with the United States Advanced Battery Consortium Tech Team

• Prepared a Statement of Work for RFP from industry (car makers, 

battery developers, battery integrators, universities, and software 

companies). 

– The purpose was to seek cross-cutting teams to “develop suites of 

software tools that enable EDV battery community to simulate and design 

battery packs.” 

• NREL issued the CAEBAT RFP on July 30, 2010; many proposals 

received by September 24, 2010.

• Total DOE/NREL funding is set to be $7.5M over three years with 

required 50% cost-sharing from participants a project totaling $15 M.

• Source Evaluation Team (SET) consisting of experts from NREL, DOE, 

and other organizations discussed the proposals during the first two 

weeks of October 2010.

• By the end of October, the SET reviewed, scored and ranked the 

proposals; recommended the top three teams for further consideration.
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Pending Collaborations with Industry

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Accomplishments 

• Three industry-led teams were selected for further negotiation with 

potential awards

• Staff from NREL Contracts and Business Services, with input from 

three NREL technical monitors, initiated negotiations with the teams 

to arrive at the subcontracts based on Terms and Conditions dictated 

by the RFP and the DOE Prime Contract.

• As of the date of preparation of this presentation (3/21/2011), we 

have resolved all issues except for a few intellectual property (IP) 

concerns – NREL and the industry teams are determined to resolve 

the IP issues shortly. 
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NREL Battery Modeling Under CAEBAT

16
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NREL’s Multi-Scale Multi-Dimensional Model

17

Relevance

• Introduces multiple computational domains for corresponding length scale 

physics 

• Decouples geometries between submodel domains

• Couples physics in two ways using predefined inter-domain information 

exchange

• Selectively resolves higher spatial resolution for smaller characteristic 

length scale physics

• Achieves high computational efficiency

• Provides flexible & expandable modularized framework
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We Selected These Cell Designs for Demonstrating MSMD Model Utility

Case Description Lx [mm] Ly [mm] Lz [mm] Tab width [mm] Tab configuration

ND Nominal design 200 140 7.5 44 Adjacent tabs

CT Counter tab design 200 140 7.5 44 Counter tabs

ST Small tab design 200 140 7.5 20 Adjacent tabs

WS Wide stack-area design 300 140 5.0 44 Adjacent tabs

Nominal Design

Small Tab Design

Counter Tab Design

Wide Stack Area Design

ND

ST

CT

WS

Tab Location

Stack Area

Tab Size

18

Accomplishments 
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0 5 10 15 20

2.5

3

3.5

4

discharge capacity [Ah]

voltage [V]

ND

CT

ST

WS

MSMD Model Shows Impact of Geometry and Tab Locations on Internal 

SOC Imbalance (Cell with wide stack area design is worst)

0 49.5

50

50.5

51

51.5

52

ND

ST

CT

WS

Accomplishments 

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All cases under 5C Discharge 
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MSMD Model Shows Impact of Geometry and Tab Locations on Heat 

Generation and Temperature 

0 5 10 15 20

0

5

10

15

20

25

30

35

40

discharge capacity [Ah]

heat generation [W]

ND

CT

ST

WS

0 5 10 15 20

25

30

35

40

45

50

55

discharge capacity [Ah]

temperature (°C)

0 5 10 15 20

25

30

35

40

45

50

55

discharge capacity [Ah]

temperature (°C)

0 5 10 15 20

25

30

35

40

45

50

55

discharge capacity [Ah]

temperature (°C)

Total Heat Generation

CT ST WS

Temperature

• Similar average temperatures: ND, CT, ST

• Smaller ∆T at CT

• Larger ∆T at ST

• Heat generation is highest with WS, but the average 

T at the End of Discharge (EOD) is lowest

ND

Single side cooling on top surface

 With h = 25 W/m2K

 At Tamb= 25°C

Accomplishments 

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All cases under 5C Discharge 
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Developed Battery Model for Spirally Wound Cells

Stacking process: Forming a pair between inner electrodes 

current collector

current collector

separator

Winding process: Forming a second pair between outer electrodes

electrode

electrode

Spirally Wound Cell : 

Pairing Inner 

electrodes

separator

electrode

electrode

Pairing Outer 

Electrodes

• One pair of wide current collector foils

• Two pairs of wide electrode layers

• Complex electrical configuration

Accomplishments 

21
The MSMD Model Showed the Larger the Numb

better the Thermal Performance

Accomplishments 

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Collaborations and Partnerships

23

• Collaborating with other national labs to add to 

the portfolio of capability for CAEBAT

– ORNL (open architecture software)

– LBNL (material and electrode models)

– ANL (material, degradation and cost models) 

– SNL (material safety database and models)

– INL (electrolyte and degradation models)

– LLNL (safety modeling)

• Pending cost-shared subcontracts with three 

industry teams (in negotiations) to develop 

battery CAE design tools

• Colorado School of Mines – integrated general 

chemistry solver for charge transfer and side reactions in 

Li-ion 
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Publications and Presentations

24

Multi-Domain Modeling of Lithium-Ion Batteries Encompassing Multi-Physics in 

Varied Length Scales, Gi-Heon Kim, Kandler Smith, Kyu-Jin Lee, Shriram 

Santhanagopalan, and Ahmad Pesaran; submitted to Journal of The Electrochemical 

Society, March 2011. 

Integrated Lithium-Ion Battery Model Encompassing Multi-Physics in Varied 

Scales, Gi-Heon Kim, Kandler Smith, Kyu-Jin Lee, Shriram Santhanagopalan, Ahmad 

Pesaran; presented at the 11th International Advanced Automotive Battery Conference, 

Pasadena, CA, January 24–28, 2011.

Accelerating Design of Batteries Using Computer-Aided Engineering Tools, Ahmad 

Pesaran, Gi-Heon Kim, Kandler Smith; presented at 25th Electric Vehicle Symposium, 

Shenzhen, China, November 5–9, 2010.

Prediction of Multi-physics Behaviors of Large Lithium-Ion Batteries During 

Internal and External Short Circuit, Gi-Heon Kim, Kyu-Jin Lee, Lawrence Chaney, 

Kandler Smith, Eric Darcy, Ahmad Pesaran; presented at Battery Safety 2010 in 

conjunction with 6th Lithium Mobile Power, Boston, MA, November 3, 2010.

3D Thermal and Electrochemical Model for Spirally Wound Large Format Lithiumion Batteries, Kyu-Jin Lee, Gi-Heon Kim, Kandler Smith, presented at the 218th ECS 

Meeting, Las Vegas, NV, October 14, 2010.

Computer-Aided Engineering of Automotive Batteries, Ahmad Pesaran, Gi-Heon 

Kim, and Kandler Smith; presented at the AABC 2010 meeting, Orlando, FL, May 18–21, 

2010.
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Future Work: Battery CAE

25

• Finalize negotiations with the three industry teams to 

execute subcontracts per RFP terms 

• Plan kick-off meetings with each CAEBAT-RFP project 

team to start work

• Finalize the CAEBAT project plan

• Interact with ORNL on the open architecture software 

• Finalize roles of other national labs

• Integrate various models in one single platform for industry 

use

• Perform bottom-up model validation study

• Enhance physics of various models

• Incorporate enhanced solver capabilities and solution 

schemes

• Hold a conference on Computer-Aided Engineering and 

Modeling for Automotive Batteries
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Summary: Computer-Aided Engineering for Batteries 

26

• Computer-aided engineering (CAE) tools have been 

widely used by many industries to design products in a 

shorter amount of time and with lower cost.

• In April 2010, DOE initiated a new program activity 

(called CAEBAT) to incorporate existing and new battery 

models into software modeling suites/tools to shorten 

design cycle and optimize batteries (cells and packs) for 

improved thermal uniformity, safety, long life, low cost

• NREL was assigned to coordinate the program with 

other national labs. 

• NREL issued a RFP ($7.5M for 3 years, plus cost share) 

and screened three industry teams for further 

negotiations – pending IP issues

• NREL has been enhancing and further developing its 

battery models to support CAEBAT program participants.
NATIONAL RENEWABLE ENERGY LABORATORY 27

Technical Back-Up Slides
NATIONAL RENEWABLE ENERGY LABORATORY

Charge Conservation

r

( ) φφη es −−= U

MSMD: Extending Beyond Porous Electrode Model

28

( ) qTk

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

ee

eff

Dee

eff

ss

eff

es

Li c

T

U jq φφ TU  κφφκφφσ ∇⋅∇+∇⋅∇+∇⋅∇+ 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

CT

WS

Temperature Imbalance at End of Discharge

29

X(mm)

Y(mm)

0 50 100 150 200

0

50

100

X(mm)

Y(mm)

0 50 100 150 200

0

50

100

X(mm)

Y(mm)

0 50 100 150 200

0

50

100

X(mm)

Y(mm)

0 50 100 150 200

0

50

100

X(mm)

Y(mm)

0 50 100 150 200

0

50

100

X(mm)

Y(mm)

0 50 100 150 200

0

50

100

X(mm)

Y(mm)

0 50 100 150 200 250 300

0

50

100

X(mm)

Y(mm)

0 50 100 150 200 250 300

0

50

100

47

48

49

46

47

48

49

50

51

43

44

45

46

47

48

ND

ST

Tavg= 48.1°C

∆T = 4.3°C

Tavg= 48.0°C

∆T = 2.9°C

Tavg= 48.5°C

∆T = 5.3°C

Tavg= 44.7°C

∆T = 6.0°C

Cooling 

Surface

Bottom

Surface

29
NATIONAL RENEWABLE ENERGY LABORATORY 30

Discharge kinetics rate comparison

Number of Tabs Impact Performance 

X [m]

Y [m]

0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

0

0.05

0.1

120 121 122 123 124 125 126 127 128 129 130

X [m]

Y [m]

0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

0

0.05

0.1

X [m]

Y [m]

0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

0

0.05

0.1

X [m]

Y [m]

0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

0

0.05

0.1

i

” [A/m2]

0.2%

2.2%

6.6%

32.2%

Δi

”

/ i

”

avg

2 tabs

5 tabs

Continuous tab

10 tabs

in the inner electrode pair at 5 min