Energy Efficiency &

Renewable Energy

Vehicle Battery R&D Progress and

Future Plans

Tien Q. Duong

Office of Vehicle Technologies

U.S. Department of Energy

KSAE and IEA IA-HEV

International Symposium on Electric Mobility

and

IA-HEV Task 1 “Information Exchange” Meeting

30 April 2015

Energy Efficiency &

Renewable Energy

2

Charter

Objective

– Advance the development of batteries and other electrochemical energy

storage devices to enable a large market penetration of electric drive vehicles.

Target Applications

– 12V Start/Stop

– Power-Assist Hybrid Electric Vehicles (HEVs)

– Plug-in Hybrid Electric Vehicles (PHEVs)

– Battery Electric Vehicles (EVs)

Drivers

– Energy security

– Greenhouse gas emissions reduction

– CAFE Standard – 54.5 MPG for all light duty vehicles (effective 2025)

Energy Efficiency &

Renewable Energy

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Applied Battery

Research (ABR)

Cell Design and

Optimization

Vehicle Technologies Office: Battery R&D Activities

3

Advanced Battery Materials

Research (BMR)

Novel Materials

Advanced Models & Diagnostic

Tools

Advanced Battery

Development/USABC

Prototype Development &

Optimization

Cycle Life Improvement & Cost

Reduction

0.5 –1.0 Ah cells 5 – 40+ Ah cells

Cell Targets

350 Wh/kg

750 Wh/l

1,000 C/3 cycles

250 Wh/kg

400 Wh/l

2,000 W/kg 4 –10 mAh cells

Anodes

(>600 mAh/g)

Cathodes

(250+ mAh/g)

Electrolytes

(>4.3 Volts)

Energy Efficiency &

Renewable Energy

4

-

100.000

200.000

300.000

400.000

500.000

600.000

700.000

Li-ion PHV/EV

Li-ion HEV

NiMH HEV Light-duty Trucks

NiMH HEV Cars

Year

ED

V S

ale

s

2.65 GWh of Lithium-ion Batteries were installed in Electric Drive vehicles

sold in the USA in 2014.

U.S. Electric Drive Vehicle Sales,

by Technology (1999-2014)

Energy Efficiency &

Renewable Energy

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Projected Cost for a 100kWh Battery Pack

Source: ANL BatPaC

Extensive cost

modeling has been

conducted on

advanced battery

chemistries using the

ANL BatPaC model.

These are the best

case projections: all

chemistry problems

solved, performance

is not limiting,

favorable system

engineering

assumptions, high

volume manufacturing

USABC EV

45kWhuse

Future Battery R&D

Advanced Battery Chemistries

Energy Efficiency &

Renewable Energy

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Advanced Battery Materials

Research (BMR) Program

Previously known as:

– Batteries for Advanced Transportation Technologies (BATT)

– Exploratory Technology Research (ETR)

10 Topic areas, 52 research projects

– Electrode modeling, diagnostics, cell analysis, silicon anodes,

cathodes, liquid electrolytes, metallic lithium & solid electrolytes,

sulfur electrodes, lithium air and sodium ion batteries.

Participants include universities, national laboratories, and

industry.

Funding mechanisms:

– Annual Operating Plan (AOP) process via Lab Call for the national

laboratories.

– Federal opportunity announcements (FOAs) for awards to

universities and industries.

6

Energy Efficiency &

Renewable Energy

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Fundamental advances in Si

anodes

Emphasis: Generate high-capacity reversible Si with good rate capability and cycle life

7

Si Nanotube: HRTEM

100 nm Challenges:

Large first-cycle irreversible loss

Low loading/areal capacity

Large capacity fade

Poor coulombic efficiency

Inferior rate capability

Approaches:

Novel architectures: Nanotubes

(NTs), Nanowires, core-shell

structures, composites

Functional coatings: Metals,

oxide coatings, Li+ and e-

conducting ceramics, carbon

based systems

Binders: High strength and

elastomeric polymers

Electrolyte additives: VC, FEC

Only 2 wt% PFM conductive

binder needed to obtain stable

capacity in SiO anodes

Si pomegranate structures demonstrating

exceptional stability over >500 cycles

Reactive molecular dynamics simulations

of the lithiation of Si-core/SiO2-shell

nanowires showing immediate lithiation

of the SiO2 shell without volume

expansion, then lithiation of the Si core

Energy Efficiency &

Renewable Energy

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Towards Commercialization

of Si anode - SiNANOdeTM

8

Production process using battery

grade graphite as direct substrate

for Si nanowire growth

– Cost effective and high Si

throughput

– Improves dispersion within

slurry and drop in process

– Si-C conductivity

improvement

– Tailored Si Weight % or

anode specific capacity ~ 500

- 1600 mAh/g

– High electrode loading

(1.5g/cm3)

– Good cycling performance up

to 1,000 cycles

SiNANOdeTM material deforms to

fill void areas in carbon anode

material matrix

SiNANOdeTM material remains

intact and fully functional after

100% DoD cycling

Thin SEI formed on Si nanowires

Energy Efficiency &

Renewable Energy

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Advanced Cathodes

9

Challenges:

Limited by the cathode performance –

materials changed little over 20 years.

Current cathodes are limited to 4.3V–

electrolyte oxidation at high voltages.

Excess Li materials show promise but are not

ready for prime time due to issues with voltage

fade, high impedance, and low tap density.

Approach:

Understand reactivity at voltages above 4.3V

and design new materials

– Electrolytes to operate at high voltages

– Additives to form artificial coatings on

cathodes

– Inorganic coatings to “protect” the cathode

Understand phase transformation in excess Li

cathodes to design better materials.

Li/TM

Li/TM

Li/TM

Discharged

Charged

Discharged

Hysteresis

Voltage Fade

2

2.4

2.8

3.2

3.6

4

4.4

4.8

0 0.4 0.8 1.2 1.6 2

Vo

ltag

e vs

. Li,

V

Capacity, mAh/cm2

2-4.7V, RT, after 1 cycle

2-4.7V, RT, after 80 cycles

Energy Efficiency &

Renewable Energy

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Voltage Fade in LMR-NMC

Necessitates Compromise

10

LMR-NMC, with no voltage fade, has the same energy density as NCA but is less expensive.

LM

R-N

MC

LM

R-N

MC

NC

A

Voltage vs. Graphite

4.70 4.25 4.25

LMR-NMC: Still the best option

0 5 10 15 20

550

660

770

880

990LMR-NMC, 2-4.7 V

Optimized LMR-NMC, 2-4.6 V

LMR-NMC, 2-4.30 V

NCA, 2-4.25 V

Wh

/Kg

oxid

e

Cycle Number

NMC, 2-4.25 V

Source: ANL BatPaC

Energy Efficiency &

Renewable Energy

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Li Metal Anode

Opportunity

Dramatic increases in specific and

volumetric energies possible.

Objectives

Key technical hurdle is to prevent the gradual

loss of lithium and impede dendrite formation

while providing adequate power.

This will be addressed through:

– Improved understanding of the chemical and

physical processes that consume lithium at the

electrode-electrolyte interface

– Electrolyte additives to prevent dendritic Li growth

– Engineered barrier materials, solid or liquid

electrolytes, to stabilize the anode-electrolyte

interface 11

Evolution of an SEI Layer on Cycling of a

Metallic Lithium Electrode (scale bars

represent 100 microns)

Before cycling (with SEI layer)

10 cycles

Source: ORNL

Energy Efficiency &

Renewable Energy

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Li Metal Anode (2)

12

Started in 2011, currently over

2,000 BlueCar vehicles available

for rental from Autolib’– one-way

car sharing in Paris.

Technology is based on

Li0/PEO/LiFePO4 operating at

60°/80°C

Batteries (30 kWh) are currently

manufactured in:

– Boucherville, Montreal

– Brittany, France

Demonstrated 3,000 cycles when

discharged to 50% DOD

Energy density: 100 Wh/kg

BlueCar – Electric Vehicles with

Lithium Metal Battery

Energy Efficiency &

Renewable Energy

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Li Metal Anode (3)

Study the use of Cesium

salts and organic additives

to typical carbonate solvents

to impede dendrite formation

(PNNL).

Apply interfacial layers

between lithium metal and

electrolyte to stabilize the

lithium surface upon cycling

(Stanford University).

13

Stable lithium metal cycling enabled by

interconnected carbon hollow spheres. (a)

Fabrication process (b) SEM images. (c) Cycling

performance of lithium metal with (solid) and

without (open) hollow carbon coating at different

current densities

Source: Stanford University, SLAC

Approach

Energy Efficiency &

Renewable Energy

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Solid Electrolytes

Barriers

Not all are stable against lithium

Have relatively poor ionic conductivity

Exhibit inherently very large interfacial impedance

Brittle and difficult to fabricate

Approach

Perform mechanical studies through state-of-the-art nano-indentation

techniques to probe the surface properties of the solid electrolyte and the

changes occurring to lithium (ORNL, UTK, UM).

Develop composite electrolytes (polymer and ceramic electrolytes) –

investigate lithium ion transport at the interface to study the effective ionic

conductivity achievable for the composite membrane (ORNL).

Identify the relation of defect types that could impact the current density

limit in Garnet-based electrolytes (UM).

Computationally and experimentally study the interfacial structure-

impedance relationship in Garnet-based electrolytes to design new

materials (U Maryland).

14

Energy Efficiency &

Renewable Energy

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Solid Electrolytes: Interfacial

Impedance

Custom cell to extract interfacial impedance

15

Organic electrolyte

Porous cathode Li metal

Single Ion Conductor (SIC)

Focus: Quantify impedance

at the interface of SIC and

liquid electrolyte

Source: LBNL

Ohara glass® LICGC

Energy Efficiency &

Renewable Energy

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High Interfacial Impedance:

Potential Show Stopper

16

1

6

LiPF6 in EC/DEC

High impedance not a function of concentration or nature of electrolyte

Typical electrode is highly porous:

Large area for ion transfer

Ceramic separators have lower area:

Impedance caused by area difference?

From: Ohara data sheet

Typical Li-ion

resistance

Source: LBNL

Energy Efficiency &

Renewable Energy

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Summary

Vehicle Technology Office continues to work closely with USABC,

Industry, Academia and the National Laboratories to advance

battery technologies.

Advanced Battery Materials Research (BMR) Program underwent a

recent name change

– Previously known as BATT, ETR

– Name better reflects the materials focus of the program

– 10 Topic areas

– 52 Research projects

Annual Merit Review Meeting

– Crystal Gateway Marriott, Crystal City, VA

– June 9 - 11, 2015

– Showcase 35 oral presentations of the BMR program

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Energy Efficiency &

Renewable Energy

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Thank you for your attention!