a Suite of Thermally Coupled Battery Simulation Tools for ... · Engineering Widely used by leading...

a Suite of Thermally Coupled Battery Simulation Tools

for large-format Li-ion Batteries

200 Innovation Boulevard

State College, PA 16803 U.S.A.

www.ecpowergroup.com

EC Power

2

EC Power is a solution provider for battery and fuel cell

technologies, specializing in design, prototyping, analysis,

and testing of batteries, fuel cells, and energy storage

systems for applications to vehicle electrification,

renewable energy, and grid power management.

EC Power Softwares

EC Power Technology

EC Power Customized

Solutions

Solutions

© 2013 EC Power LLC. All Rights Reserved

Fastest Growing Simulation Tool for Li-ion Battery

Engineering

Widely used by leading industrial organizations battery supplier to Auto OEMs,

growing customer base, rave reviews by DOE

Ford Motors company, “Li-ion Electrochemical

Model”, 2012 Automotive Simulation World

Congress Link: Ford Presentation

AutoLionTM highlighted

in new book

C.D. Rahn and C.Y. Wang,

Battery Systems

Engineering. Wiley (2013)

AutoLionTM in US Drive 2012

accomplishments

Link: US Drive 2012

accomplishment

Industrial leaders across the

world in Li-ion battery space (cell

manufacturer to Auto OEMs) are

using AutoLionTM

“The key concerns of both the battery supplier

and the automotive industry could be addressed

by the EC Power model and consequently made

it not only a useful tool, but a user friendly tool

as well.” . DOE Reviewer

AutoLionTM in DOE funded

CAEBAT project Link: DOE 2012

Annual Review

EC Power is the only company selected for US

DOE award (2013) for Li-ion battery safety and

life modeling tool development/enhancement

Link: FY2013 DOE Vehicle Technology Program

Award List


http://www.ansys.com/staticassets/ANSYS/Conference-2013/Static Assets/li-ion-electromechanical-model-ford.pdf

http://www.amazon.com/Battery-Systems-Engineering-Christopher-Rahn/dp/1119979501/ref=sr_1_1?ie=UTF8&qid=1376082835&sr=8-1&keywords=battery+systems+engineering

http://www1.eere.energy.gov/vehiclesandfuels/news/news_detail.html?news_id=19121




http://www1.eere.energy.gov/vehiclesandfuels/pdfs/merit_review_2012/2012_amr_02.pdf

http://www1.eere.energy.gov/vehiclesandfuels/pdfs/merit_review_2012/2012_amr_02.pdf

http://www.eere.energy.gov/pdfs/funding_selections_9-4-13.pdf

http://www.eere.energy.gov/pdfs/funding_selections_9-4-13.pdf

AutoLionTM: EC Power’s Li-ion Battery Software Suite

4

AutoLion-3DTM is ideal for Li-ion

battery pack thermal management and

on-field relevant cell/pack safety

simulations

User Benefits:

Accurate over wide range of

operating conditions for Li-ion battery

pack thermal management and

evaluation of innovative cooling

concepts

On-field relevant safety simulation

(internal short, external short etc.)

Compatible with any commercial

CFD environment

AutoLion-1DTM is physics-based Li-ion cell

simulation tool perfect for cell design and

optimization

User Benefits:

Fast evaluation of various battery

chemistries and cell designs under

extreme operating conditions

Investigation of internal cell

mechanisms that dictate performance

and safety

Reliable predictions of Li-ion

degradation/aging over wide range of

operating conditions

AutoLion-STTM is physics-based

embedded-in-Simulink Li-ion battery

system design and optimization tool

User Benefits:

Non-empirical software-in-the-loop

tool for battery system architecture

selection, design and operation

Cost and time effective: No need to

extract circuit parameters from data

for every battery pack

Accurate system life-cost

optimization for any energy storage

system with one or more energy

sources

2.5

3

3.5

4

0 275 550 825 1100

Cell

Vo

lta

ge (

V)

Cell Capacity (mAh)

AutoLion

Isothermal Newman Model

-25°C Voltage Comparison at 1C Discharge


Electrochemical Processes

- electrochemical reactions

- solid state diffusion

- ion transport through

electrolyte

- charge transfer

Thermal Processes

- conservation of thermal energy

Heat generation rate

Temperature-dependent

physico-chemical properties

TTR

E

ref

act

ref

11exp ,

Model predictions

- dynamic potential and current curves

- temperature history and distribution

- active material utilization

qT

t

Tcp

λ

k

k

kk

j

jjnjsjiaq

i

AutoLionTM is unique because it is the

only commercially available software to

take an integrated approach to

electrochemical-thermal coupling in Li-

ion batteries.

With AutoLionTM, the dominant

mechanisms that dictate cell performance

are numerically resolved simultaneously,

with temperature effects fully calculated

and incorporated into each time step.

This fundamental approach is called

Thermally Coupled Battery (TCB)

modeling, and is exclusive to all

AutoLionTM products. Benefits of utilizing

this TCB approach include:

• Pack thermal management for wide

range of operating scenarios

• Voltage recovery at low-T discharge

• Safety simulations

• Degradation/aging simulations

AutoLionTM: Thermally Coupled Battery Modeling

Approach

Capacity (mAh)

Vo

lta

ge

(V)

Te

mp

era

ture

Inc

rea

se

(C

)

0 500 1000 1500 2000 25002

2.5

3

3.5

4

0

20

40

601C (2.2A) Discharge

Model

Experimental data

45C

25C

0C

-10C

-20C

Prediction of voltage recovery (experimentally observed) from

low T only possible with AutoLion TCB modeling


AutoLionTM: Unprecedented Accuracy in Capturing Li-

ion Battery Performance

Discharge Capacity (mAh)

Vo

lta

ge

(V)

Te

mp

era

ture

Inc

rea

se

(C

)

0 500 1000 1500 2000 25002

2.5

3

3.5

4

0

20

40

60

80

0.1C(0.22A)

1C(2.2A)

3C(6.6A)

4.6C(10A)

Discharge at 25CModelExperimental data

Capacity (mAh)

Vo

lta

ge

(V)

Te

mp

era

ture

Inc

rea

se

(C

)

0 500 1000 1500 2000 25002

2.5

3

3.5

4

0

20

40

601C (2.2A) Discharge

Model

Experimental data

45C

25C

0C

-10C

-20C

Cell: 2.2 Ah 18650 cell with NMC/graphite chemistry

AutoLionTM captures battery performance and temperature profile with

great accuracy


AutoLion: a Perfect Tool to Capture Li-ion Battery

Dynamics

Cell Starting SOC = 50%


Simulation results matches very well with data with

maximum error being less than 2% error; showcasing

excellent accuracy of AutoLion-STTM under dynamic

conditions

Cell Starting SOC = 90%

-15

-10

-5

0

5

10

15

0 100 200 300 400

Cu

rre

nt

(A)

Time (Sec)

Input Current Profile

10C

discharge

charge

Cell: 1.2 Ah high power 18650 cell

Chemistry: NMC/Graphite

Experiments carried out at 25oC inside an

environmental chamber

2 cells repeat

8

AutoLionTM: Physics-Based Predictive Life Modeling

Capabilities Cell chemistry: NMC/graphite

AutoLionTM can not only capture cell behavior but

also the voltage decay of each electrode with cycling

over a wide range of operating conditions

Capacity (mAh)

Ca

tho

de

Po

ten

tia

lv

sL

i/L

i+(V

)

0 200 400 600 800 1000 12002.5

3

3.5

4

4.5

01000200030004000

50C 5C cycling

25C 1C characterization

Capacity (mAh)

Ce

llV

olt

ag

e(V

)

0 200 400 600 800 1000 12002

2.5

3

3.5

4

01000200030004000

50C 5C cycling


Capacity (mAh)

An

od

eP

ote

nti

alv

sL

i/L

i+(V

)

0 200 400 600 800 1000 12000

0.1

0.2

0.3

0.4

0.5

01000200030004000

50C 5C cycling


Cathode voltage plots

Anode voltage plots

Cell voltage plots

Life predictions against third party data*

for LFP/graphite 26650 cell

*J. Wang et al., J Power Sources, 196, 3942 (2011) © 2013 EC Power LLC. All Rights Reserved

• Virtual cells/packs case files

– Can use “off-the-shelf” case files for cells

– Can design own virtual cell for exploration

AutoLion™: User-Friendly Battery Simulation Tool

9

Display window

Summarizes key cell specification in Design Report tab

Designer window

Use the collapsible node tree to select and view detailed design parameters for the virtual cell/pack

Parameter window Edit the current values selected on the Design Window above

AutoLionTM Virtual Battery Lab (VBL) to

“virtually” fabricate a cell


AutoLionTM: Software Materials Database

10

Cathode materials:

• NCM

• LFP

• LMO

• LCO

Anode Materials:

• Graphite

• LTO

100,000+ Coin cells built and tested to

acquire temperature/concentration

dependent properties

8 Built-in cell chemistries

that can be instantly

created and simulated.

All AutoLionTM softwares come equipped

with the material data built-in, which offers

the following benefits:

• No testing required from the end user

• Instant access to all 8 cell chemistries:

new cells can be designed in a matter of

minutes

• High quality data at various

concentrations and temperatures

• Users have freedom to input their own

properties as a function of temperature

and SOC through user defined functions

Li+

negative electrode positive electrode separator

4M

0.1M

1M

Ele

ctro

lyte

Conce

ntr

atio

n

Electrolyte distribution in

a Li-ion cell under

discharge

Data collected for electrolyte concentrations

ranging from 4M to 0.1M

-30°C 60°C

Users do NOT need a detailed understanding of battery cell electrochemistry to work with

AutoLion!


• AutoLion-ST™ is a physics-based model embedded in Simulink

– Thermally-coupled for co-simulation with other system components (radiators, fans,

pumps, etc.) and with other power sources (hybrid vehicle, microgrids etc.)

– Software-in-the-loop model of a Li-ion battery pack

• Accurate over wide-ranging operating conditions

• Exploratory model (non-empirical)

• Virtual design of Li-ion batteries and packs (system design possible before

cell/pack design finalized)

– Ideal for development of advanced control strategies

AutoLion-ST™: User Empowering System

Simulations

11

Inverter

Fuel Cell (or other Battery)

DC/DC Boost

Li-ion Battery Pack

Electric Motor

IC Engine

Generator

Li-ion Battery

Pack

Electric Motor

Inverter

Li-ion storagebattery

EV charging

Renewable energysource


12

System Requirements:

• Windows 7 64-bit

• Matlab (w/Simulink) ver. 2011a or later

• At least 2 GB of RAM

System Simulation using an Equivalent Circuit (EC) : - Largely empirical where every new battery pack

needs to be experimentally characterized over a wide

range of operating conditions to create a map or look

up table for resistance and capacitance dependence

on SOC, temperature, and C-rate

- Lack the ability to capture important features such as

temperature effects and rate-dependent capacity

System Simulation using AutoLion-STTM : - Use the AutoLion TM Virtual Battery Lab (VBL) to

select materials, geometry, and pack properties

- Connect ALST block into the desired system

- Run the simulation

- Post-process the data

- Fully capable to simulate pack life and dynamic

response over a wide range of operating conditions

Time scale: minutes

AutoLion-ST™: Non-Empirical Software-in-loop

Time scale: weeks

AL-ST

• Thermodynamics (OCP)

• Charge transfer kinetics

• Conservation laws

• T-dependency of material

properties

Electrical Load

Conditions (e.g. I(t)

or P(t))

Thermal conditions

(Tamb, coolant rate)

Battery design, Initial States

(SOC and/or SOH)

V(t)

P(t)

T(t)

Csolid,Li to avoid

Li plating, etc.

SOC(t)

Celectrolyte,Li

Capacity(t)Battery

controller

Output

Initial

guess


13

AutoLion-STTM vs. Existing System Simulation Tools

AutoLion-ST (AL-ST)

Single Particle Reduced

Order Model (ROM)*

Enhanced Single Particle

ROM **

NCM/Graphite Li-ion Chemistry

25oC Operation

0oC Operation

Single particle and enhanced ROM model may

provide similar accuracy as physics-based AL-ST

at room temperature but over a wide range of

temperature substantially fall short in capturing

accurate behavior owing to their underlying

assumptions

AutoLion-STTM captures accurate battery internal

physics for system-level simulation without

sacrificing on computational efficiency

* K. smith et al, ASME J Dyn. Syst. Meas. Control, 130, 011012 (2008)

** T.R. Tamin et al., Ener. Conv. Management, submitted


Forecasting of Battery Pack Ageing under User-

Specified Drive Cycle with AutoLion-STTM

14

Li-ion Battery Pack

Tambient

Tbattery

-

+

-80

-60

-40

-20

0

20

40

60

80

100

0 200 400 600 800 1000 1200

Po

we

r D

em

an

d (

kW

)

Time (sec)

PID Controller

Heat transfercoeff. h(t)

Tbattery

US06 drive cycle

Thermal Controller

Rapid drop in capacity and peak power for warmer

conditions

After 1000 cycles

– Phoenix (35oC): ~ 15% drop in capacity, ~ 12%

drop in peak power

– Portland (10oC): ~ 5% drop in capacity, ~ 3% drop

in peak power

Cell and pack design (both electrochemical and thermal)

can be modified on the fly and re-simulated within

minutes

Li-ion battery

pack with 96S3P

configuration

at 40% SOC; 25oC


15

Dynamic System Simulation for Hybrid Powertrain

Greater Li-ion battery pack overpotential at 0oC leads to lower voltage and greater current to generate required

load

Li-ion battery pack voltage recovery attributed to both reduced load (over time) and battery self-heating during

discharge

With AutoLion-STTM, custom controls, system designs, and thermal management strategies can be readily

developed for a hybrid energy storage system with any combination of two energy sources such as but not

limited to lead-acid battery coupled with Li-ion, two Li-ion batteries or fuel cell-battery hybrid. Contact EC

Power for lead-acid battery or fuel cell system tools.

Dynamic load sharing between

Fuel Cell and Battery

Dynamic response of Li-ion battery

pack at different ambient conditions


16

Design a custom cell and run/view the

simulation within the self contained GUI


- Windows 7 64-bit

- 150 MB of hard disk space

- At least 2 GB of RAM

NCM-Graphite 18650 cell

simulated at with proper

electrochemical-thermal coupling

(AutoLionTM) vs. isothermal

Newman-type model.

Voltage response of an LFP-

graphite prismatic cell for a custom

power load profile.

Rapid simulations with AutoLion-

1DTM to compare various cell

chemistries

2.5

3

3.5

4

0 275 550 825 1100

Cell

Vo

lta

ge (

V)

Cell Capacity (mAh)

AutoLion

Isothermal Newman Model

-25°C Voltage Comparison at 1C Discharge

2.8

3.2

3.6

4

1000 1020 1040 1060 1080 1100

Cell

Vo

lta

ge (

V)

Time (sec)

Voltage Response

4.4Ah 0.9SOC

4.4Ah 0.5SOC

AutoLion-1D™: Rapid Modeling of Li-ion Cell


Capacity (mAh)

Vo

lta

ge

(V)

0 500 1000 1500 20001

1.5

2

2.5

3

3.5

4

OCV

1C

3C

5C

Graphite : NCM-LMO-LFP

Thickness(m): A(63)-S(20)-C(79)Porosity: A(0.27)-S(0.46)-C(0.27)

Capacity (mAh)

Cu

rre

nt

Pe

rce

nta

ge

(%)

0 500 1000 1500 20000

50

100

NCMLMOLFP

Graphite : NCM-LMO-LFP

1C discharge

• Explore performance of blended cathodes using AutoLion-1D™

• Use any combination and % of active materials in the materials database

AutoLion-1DTM: Simulating Mixed Active Material as Used in

State-of-the-Art Commercial EV Technology


External Short Circuit Simulation with

AutoLion-1DTM

18

Three different 18650 cells designed for high power (1.2Ah,

100 Wh/kg), medium energy (e.g. PHEV cell) (2.2Ah, 150

Wh/kg) and high energy (2.8Ah, 200 Wh/kg) are chosen.

o Cell chemistry: NMC/graphite

(properties taken from AutoLion-

1DTM database

o External short resistance: 100 mΩ

Counterintuitive to conventional wisdom, the 2.8Ah cell reach the cut-

off voltage of 2.2V prematurely, resulting in a relatively benign cell

temperature rise during external short

Cell response during a safety event is a strong function of cell internal

behavior dependence on temperature. 2.8 Ah cell could tolerate external

short without any drastic consequences (T<100oC) because of electrolyte

depletion

AutoLion-1D™ simulation results clearly show that the limiting current

for high-density electrode cells, with minimal pore volume for

electrolyte, is dictated no longer by the electrode active material but

rather by electrolyte amount and transport properties

Voltage and temperature response after

external short event

Electrolyte depletion in 2.8Ah cell

resulting in cell shutdown


Li-ion Battery Cell Aging Forecasting with

AutoLion-1DTM

19

Cycle Number

SO

H(%

)

0 1000 2000 3000 4000 50000

20

40

60

80

100

15C 0.5C

25C 0.5C

45C 0.5C

50C 0.5C

60C 0.5CCycle Number

SO

H(%

)

0 1000 2000 3000 4000 50000

20

40

60

80

100

15C 1C

25C 1C

45C 1C

50C 1C

60C 1C

Simulation of cycle life of LFP/graphite 18650 cells over a wide range of temperature and cycling rates

Rapid execution of virtual ageing experiments and rapid optimization between battery usage and

life is possible using AutoLion-1DTM © 2013 EC Power LLC. All Rights Reserved

AutoLion-3DTM

• AutoLion-3D™ is a thermally-coupled, physics-based model for reliable evaluation of

Li-ion battery pack thermal management and on-field relevant safety for packs

Compatible with any commercial CFD environment

• Acts as Plug-in library for Fluent, Star-CD etc.; AutoLion-3D ONLY uses CFD

solver to resolve AutoLion-specific equations and post-processing capabilities

• Robust and computationally efficient with parallel computing capabilities; easily

handles large mesh size (15 million or more mesh size)

Perfect for Li-ion battery pack thermal management and evaluation of innovative

cooling concepts

• Accurate over wide-ranging operating conditions

• Virtual design of Li-ion batteries and packs (estimation of various pack and

coolant design before cell/pack design finalized)

On-field safety simulation for Li-ion battery pack such as internal short, external

short in a pack, cell crush in a pack in addition to nail penetration (lab-scale safety

test)


AutoLion-3DTM : Easy to Use with a Minimal

Learning Curve

Choose battery chemistry, Design battery

cell/pack and specify operating

conditions with AutoLion -3D GUI

Use commercial mesh generation

software (ICEM or others) by quickly

importing AutoLion-3D generated

mesh scripts

AutoLion-3D governing

equations with EC Power

proprietary algorithms

Import AutoLion-3D

model to Fluent , or any

other commercial CFD

package and click

simulate


• Windows 7 64-bit (for GUI)

• Linux 64-bit (for simulator)

• Any Commercial CFD Package (e.g.

Fluent, Star-CCM+)

• Mesh generation software

• Multi-core processors for parallel

computing (optional)

AutoLion-3DTM can generate meshes for all 3 geometric types:

cylindrical, wound prismatic, and stacked prismatic.

Thermally-coupled

battery volume

averaged equations


AutoLion-3DTM: Robust CFD-Based Software

Inlet

Outlet

Inlet

Outlet

Coolant flow field

(fluid region) Li-ion cells

(solid region)

AutoLion-3DTM is very robust, and computationally efficient in simulating large packs (i.e. 22

kWh or larger)

Numerical mesh for electrochemical/thermal coupled simulation of a 22kWh battery

system (12 million mesh size)

Some highlights of AutoLion-3DTM users :

Large pack simulation (>10M mesh size) with air convection; good match between experimental

data of cell temperatures and voltage and model (Leading automaker)

Pack design evaluation for pack-level safety events against international safety standards (Leading

pack manufacturer)

Cell safety simulations and subsequent thermal runaway (Leading automaker, cell/pack

manufacturer) © 2013 EC Power LLC. All Rights Reserved

Cooling Concepts and Thermally-driven Cell-to-Cell

Imbalance with AutoLion-3DTM

Cell Group 1

Cell Group 12

Cell Group 1 Cell Group 12

12S-2P Pack (with NMC/graphite 35 Ah cells) air heating from subzero temperatures with air flow

and its impact on cell-to-cell imbalance

Thermally-driven SOC imbalance has performance, life, and safety consequences, and can only be

simulated with a TCB model such as AutoLion™


Internal Shorting Simulation

(K)

Rshort 10mΩ

Tmax= 2800 K

Rshort 4Ω

Tmax= 380 K

(K)

Temperature contours of the shorted layer (#8) in a cell 5

seconds after the shorting event.

300

600

900

1,200

1,500

1,800

2,100

2,400

2,700

0 20 40 60

Tem

pe

ratu

re (

K)

Time (s)

Tavg (K)

Tmax (K)

10 mΩ

298

308

318

328

338

348

358

368

378

388

398

0 25 50 75 100

Tem

per

atu

re (

K)

Time (s)

Tavg (K)

Tmax (K)

4 Ω

8 Ah NMC/graphite stacked electrode cell with layer #8 out of 17 layers is shorted with 10 mΩ and 4

Ω short

AutoLion-3DTM is a robust software capable of

capturing complex transients of temperature rise

and its spatial distribution during an internal short

event


Simulating Cell Crush with AutoLion-3DTM

0.1 sec 0.5 sec 1.0 sec 5.0 sec 20 sec

penetration depth due to the impact or crush is a major factor in

maximum cell temperature. Shallow indentation or slow penetration

speed is substantially more dangerous.

In this case, local temperatures approach 400°C within 0.5 seconds of penetration.

10 Ah NMC/Graphite Cell


On-Field Relevant Pack-level Safety Simulation -

External short of One Cell in Pack

24 cell 12S-2P 2.8 kWh pack consisting of 35 Ah Cell NMC/graphite cells

Air cooled pack; cell 12 is externally shorted with 10 mΩ resistance

AutoLion-3DTM is a perfect tool to evaluate the impact of on-field

safety events such as external short in a pack with and without coolant

flow

Real physics captured with AutoLion; temperature rise limited to 60oC

in this case because of electrolyte limiting phenomena. Empirical

models can’t evaluate real events like shown here

Temperature distribution in the battery pack at 12 sec (only partial view

of 24 cell pack from cell #12 to cell#24 shown for clarity) after the

external short event in cell #12

Externally

shorted cell


27

Feature AutoLion-1DTM AutoLion-STTM AutoLion-3DTM

Proprietary TCB Model

Virtual Battery Lab (VBL) with

material database

Life modeling

Safety simulation Limited capabilities

Pack simulation

Dynamic system feedback

Hybrid energy storage

simulation

Parallel computing

Batch Jobs for parametric

studies

Built-in solver Uses Simulink Any Commercial CFD

Solver

Custom load profiles

Post-processing Built-in MATLAB .CGNS format: industry

standard for post-processing

AutoLionTM : Superior Battery Simulations for

Applied Battery Research & Engineering


Contact Information

For more information on EC Power and

its products, contact us at:

EC Power

200 Innovation Blvd.

State College, PA 16803

Website: http://www.ecpowergroup.com

Email: [email protected]

Telephone: +1-814-861-6233

Fax: +1-814-861-6234


a Suite of Thermally Coupled Battery Simulation Tools for ... · Engineering Widely used by leading...

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Transcript of a Suite of Thermally Coupled Battery Simulation Tools for ... · Engineering Widely used by leading...