Roles of Modeling and Simulation in xEV Battery Revolution

Chao-Yang Wang

The Pennsylvania State University

University Park, PA 16802

ecec.mne.psu.edu

EC Power

State College, PA 16803

www.ecpowergroup.com

• Background

• Elements of Battery Modeling and Simulation

• Applications

• Summary and Outlook

Outline

Electrochemical Engine Center

(founded in 1997)

Recently renovated and facilities

upgraded with $25M

• Global competitions

• Large number vehicle models; customized systems

• Faster – traditional processes of physical build, test, system

integrate & refine are too slow to be practical

• Cheaper

• Better

• Big Data driven – unavailable life testing data over 10-20 years

• Battery safety cannot rely solely on destructive testing

xEV Battery Development Challenges

A Pathway to Reduce Cost: CAE-led Development

Vehicle crash-worthiness through simulations

1960 2000+Destructive-testing only

approach; no simulation

method existed

Industrywide adoption.

CAE-led development

with >80% reduction in

testing

Computer-aided engineering enables getting a product right

the first time and eliminate very costly issues later on

Our Process of CAE-led Battery Development

“Walk the Talk”

Battery Modeling & Simulation through e.g. GT-AutoLion

• Software suite for total battery engineering:

performance, life and safety; only industrial

project recognized by 1st and 2nd DOE CAEBAT

programs

• Fast, robust & accurate tool for real Li-ion

battery geometries

• Aid OEMs/battery developers to accelerate

product development of low-cost, safe, long-

lasting Li-ion batteries for xEVs

Materials Characterization

Set Gold Standard for xEV Battery Engineering

Physico-chemical Modeling

Computational Algorithms

Diagnostics & Validation

Performance Life Safety

2.42

2.22

2.02

1.83

1.63

1.43

1.23

1.03

0.84

0.64

0.44

He

ig

ht

(cm

)

0

2

4

6

8

10

Length (cm)

0 50 100 150 200 250 300 350 400 450

Discharge Capacity (Ah)

Ce

llV

olta

ge

(V)

0 0.2 0.4 0.6 0.8 1 1.2 1.43

3.2

3.4

3.6

3.8

4

4.2

4.4

01000200030005000

Data, Cycled Number

1C discharge

Solid Line: Model Simulation

• highest active material utilization• highest energy density (Wh/kg)• lowest cost $/kWh

• longest life• lowest life-cycle cost

• safest systems by virtual & actual testing

What is in GT-AutoLion?

Battery Materials Database

Cathode materials:

• NCM111,523, 622, 811

• LFP

• LMO

• LCO• NCA

Anode Materials:

• Graphite

• LTO

• Hard Carbon

• Si/C

• Li metal

1,000,000Coin cells built and tested to

acquire temperature/concentration

dependent properties

12Built-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:

• Instant access to all 12 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 electrodeseparator

4M

0.1M

1M

Ele

ctro

lyte

Conce

ntr

atio

nElectrolyte distribution in

a Li-ion cell under

discharge

Data collected for electrolyte concentrations

ranging from 4M to 0.1M

-30°C 60°C

Users can add any new material to the software thru UDF.

Electrolytes:

• LiPF6

• PEO polymer

• LIPON/oxides

• Sulfide electrolyte

9

Coin cells under testing

Rate performance @ RT

Capacity test @ RT

Si-Gr/NMC811 full coin cell

0 50 100 150 200 2502.5

3.0

3.5

4.0

4.5

5.0

NMC811 loading: 21.59 mg/cm2

1st cycle, efficiency: 91.05%

2nd

cycle, efficiency: 99.42%

Room temperatureC/10 charge/discharge

Coin cell: Li/NMC811

Voltag

e (V

)

Capacity (mAh/g)

0 50 100 150 200 2502.5

3.0

3.5

4.0

4.5

5.0

C/10 C/3 1C

Coin cell: Li/NMC811

NMC811 loading: 21.59 mg/cm2

Voltag

e (V

)

Capacity (mAh/g NMC)

0 50 100 150 200 2502.5

3.0

3.5

4.0

4.5

5.0

C/10 charge/discharge4.35-2.7 V

1st cycle

2nd

cycle

Room temperature

Coin cell: SiO-Gr/NMC811

Voltag

e (V

)

Capacity (mAh/g)

0 100 200 300 400 500 600 70020

25

30

35

40

90

92

94

96

98

100

Eff

icie

ncy

(%)

Capacity

(Ah)

Cycle number

Capacity

4.35V-2.7V @ 0.75C/0.75C

Cathode: NCM811Anode: SiO/Graphite

Energy density 260 Wh/kg

Efficiency

0 100 200 300 400 500 600 70060

70

80

90

100

90

92

94

96

98

100

Eff

icie

ncy

(%)

Capacity

rete

ntion (%

)

Cycle number

Capacity retention

Cathode: NCM811Anode: SiO/Graphite

Energy density 260 Wh/kg

4.35V-2.7V @ 0.75C/0.75C

Efficiency

Cycle test of a pouch cell

LiNi0.8Mn0.1Co0.1O2 (NMC811): Cathode Material for EVs in 2022

3-Yr, $1.95M DOE Project for Highly Stable NMC811 or 9055

• Need high-capacity cathode material with better safety and higher cycle/calendar life,

requiring much better stability

• NMC811 surface-coated by LixMyPO4 (LMP, M=Fe, Mg, Al, Ti or their combinations)

Cycling stability of an LFP-coated

NCM811/Graphite 2.5Ah pouch cell

cycled with 1C/1C at RT and 40oC.

SEM images of (a) original and (b) LFP-coated

NCM811 particles. (c, d) EDS elemental (P and

Co) mapping image of LFP-NCM811 particle.

XRD spectra of LFP-

NCM811 and NCM811.

Can We Trust GT-AutoLion?

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

1C (2.2A) DischargeModel

Experimental data

45°C

25°C0°C

-10°C

-20°C

2.2 Ah NMC/Graphite 18650 cell Dynamic pulse demand simulation at 0oC

for 1.2Ah NMC/C cell

Cycle life simulation for LFP/C cell External short of 1.6 Ah NMC/C cell

Case Study 1: All-Climate Battery (ACB)

• ACB: Anode + Cathode + Electrolyte + 4th Component: a µm-thin Ni foil for rapid self-

heating; 2-3oC/sec

• Self-heat in 5-15 seconds & consumes 1-3% battery energy for 20-30oC temp rise

Wang et al., Nature, 529 (2016) 515-518.

13

• Self-heating time: 12.5 sec

• (energy) capacity consumed:

2.9% of 10Ah

Self-Heating from -20oC

Highest Energy Efficiency in Real World Driving

14

ACB realized 80% of room-temperature cruise range at -30oC with present-day LiB, and

achieve 92% of RT cruise range with 300 Wh/kg LiB.

All-Climate Range (ACR) – the cruise range guaranteed in -20oC to 40oC vs. RT range

All

-Cli

mat

e R

ang

e (%

)

100

0

Zhang et al., J Power Sources, 371 (2017) 35-40.

Temperature-Independent Battery

15

2C, 3-sec disch. pulse @100%SOC

NCM523/Gr cell, 33Ah, 200 Wh/kg

Internal Resistance – DCR

(-20oC, 100% SOC) (10oC, 97%SOC)10 sec

16

Commercial Applications

• Automakers and battery manufacturers around the

world have licensed ACB technology.

• 2022 Winter Olympic Games adopted ACB for all

10,000 electric vehicles; 4 types of cars and buses are

undergoing real-world testing this winter.

>260 km range @ -30oC outdoor; no heated garage

15-60 min fast charge stations

Hill climbing @-30oC

Regeneration downhill @ -30oC

BAIC EU260 Car, Yutong Luxury Van, & Foton 12m Bus at

HaiLaer Winter Vehicle Testing Center in March 2018Testing Conditions:

• All vehicles soaked in -40oC environment

for 72 hours (no plug-in for keeping

temperature)

• In 10 min, EVs drive away like normal

vehicles (0-100 km/h acceleration, regen,

fast charging…)

SUCCESS: All 3 types of vehicles powered by MGL’s ACB batteries PASSED!!!

Courtesy: the Winter Olympic Project of testing ACB technology in vehicles was planned and led by Prof. Sun Fengchun of BIT with

active participation from BAIC, Yutong, Foton & MGL

In-Vehicle Testing of All Climate Battery

Impact of ACB on EV Market in China (60% of the World)

EV markets in thesouth & east

ACB enables EVs in Cold and High-Altitude Regions

Source: China Electric Vehicle Monitoring Platform, Industry & Information Ministry/Beijing Institute of Technology,

Courtesy per Academician Prof. Sun FengChun.

Case Study 2: Fast Charging Battery (FCB)

Fast and Healthy Charging Anywhere, Anytime

Baseline, 0oC

10 Ah PHEV cell, graphite anode, NMC622 cathode; 175Wh/kg

FCB

• Simulations on evolutions of Li

deposition potential (LDP) in AL1D can

reveal max charge rate under certain

temperature before Li plating occurs, i.e.

LDP<0V.

• Energy-dense, thicker-electrode cells

need to operate at elevated temperature in

order to avoid Li plating upon fast

charging.

• AutoLion has been an instrumental tool

in discovering and designing ubiquitous

FCBs.

Maximum Charge Rates @ Various Temperatures

Guaranteed 15-min Charging at All Temperatures

Yang et al., PNAS

(2018).

Case Study 3: Energy-Dense EV Battery with High Safety/Longevity

• If using stable active materials/electrolyte and operated under Li plating-free

condition, high-energy EV batteries (220-240 Wh/kg) could be much safer and have

3000-4000 cycles.

• This translates to >600-800k miles, or the battery can last for 50 yrs

• Uber-durable batteries should be put in multi-life reuse, increasing usage value or

equivalently cutting down battery cost for each application and/or increasing ROI.

Gen 2 EV cell 220 Wh/kg,

1C/1C cycling

Summary and Outlook

Simulation-based development of Li-ion batteries for performance, life,

safety and cost is feasible and indispensable

Along with carefully established material database, efficient numerical

algorithms, and extensive experimental validation, CAE tools will play a

major role in developing xEV battery products faster, cheaper and better.

We did not invent Li-ion battery, but we can reinvent it every day using

model-based simulation tools.

Integrated with powertrain and vehicle simulators such as GT-SUITE,

possibilities to develop innovative and energy-efficient xEVs are endless.