Fire Hazards of Lithium Ion Batteries

FEDERAL AVIATION ADMINISTRATION

Aviation Research Division

William J. Hughes Technical Center

Atlantic City International Airport, NJ 08405

*Department of Fire Protection Engineering,

University of Maryland, College Park

International Aircraft Systems Fire Protection Working Group Meeting

Dresden, Germany, May 12-13, 2015

WEB: www.fire.tc.faa.gov E-MAIL: richard.e.lyon@faa.gov

Richard E. Lyon, Richard N. Walters, Sean Crowley,

and *James G. Quintiere

Objective: Measure Fire Hazards of LIBs

Passenger electronics

Typical

packaging

Typical bulk shipment as cargo

Causes of Battery Failure

• Thermal

– Separator melts due to high temperature causing internal short circuit that releases heat.

– Contents mix, react and thermally decompose.

• Electrical

– Overcharge

– Rapid discharge

• Mechanical

– Physical damage (puncture)

– Manufacturing defect or contaminant

All lead to auto-accelerating heat

generation and rapid temperature

increase (Thermal Runaway) leading

to fire and/or explosion

< 1 second

Materials: Commercial 18650 LIB Cells

65 mm

18650 Rechargeable Cells ( 44 grams each)

18 mm

Electrical Properties of Tested Cells

LiMn2O4-LiNiCoO2

LiCoO2

LiNiCoAlO2

Unknown

Cathode

Maximum

Capacity,Qmax

(A-s)

11,700

9,400

5,400

18,000

Rated

11,200

8,300

5,000

3,600

Actual

Cell Potential,

(V) -∆G, Qmax

(kJ/cell)

41

31

19

13

3.6

3.7

3.7

3.7

Nominal

4.1

4.1

4.1

4.0

Max.

State-of-Charge, SOC = Q/Qmax

Chemical Energy Available to Do Useful Work (Free Energy), ∆G = -Q

Experimental Methods: Cell Charging

• Charge / Discharge 4 cells simultaneously

• Record: charge / discharge capacity

• Programmable for different states of charge

Methods: Hazard Measurements

Thermal Effects of Cell Failure Purpose-Built Thermal Capacitance

(Slug) Calorimeter

Energetics of Cell Failure ASTM D 5865-14, Standard Test Method for

Gross Calorific Value of Coal and Coke

Fire Behavior of Lithium Cells (ASTM E 1354, Standard Test Method for Heat and Visible

Smoke Release Rates for Materials and Products Using an

Oxygen Consumption Calorimeter)

Bomb Calorimeter (ASTM D 5865)

• Parr Instruments Model 1341 Plain Jacket Oxygen Bomb Calorimeter

• Resistance heating to force thermal runaway of LIBs

• Nitrogen blanket (1 Atm) to prevent oxidation of contents after failure

• Temperature, voltage and current logged for all tests

Bomb and other components

for 18650 battery tests

Experimental Setup

Thermodynamics of Cell Failure

Energy released by mixing, chemical

reaction and thermal decomposition

of cell components.

UTotal Urxn Q

Total energy

released at cell

failure

(measured in bomb)

Electrochemical (Free) energy release

(Calculable from cell potential (V) and

charge Q (A-s))

Depends on

cell chemistry

Analysis of Bomb Calorimeter Data

0

10

20

30

40

50

60

70

80

0 500 1000 1500 2000 2500 3000 3500 Energ

y R

ele

ase a

t F

ailu

re (

kJ/c

ell)

Charge, Q (mAh)

Free Energy, ∆G (Q)

Total Energy

(∆Utotal) Energy of Mixing, Reaction

and Decomposition, ∆Urxn

∆Urxn 90% of Q

LiMn2O4-LiNiCoO2 LiCoO2 LiNiCoAlO2 Unknown

18650 Cell Chemistry

80

70

60

50

40

30

20

10

0 0 10 20 30 40 50 60

LiMn2O4-LiNiCoO2

En

erg

y R

ele

ase

at F

ailu

re (

kJ/c

ell)

60

50

40

30

20

10

0

-10 0 5 10 15 20 25 30 35 40

LiCoO2

40

30

20

10

0

-10 0 5 10 15 20 25

LiNiCoAlO2

Electrochemical Free Energy, Q (kJ/cell)

30

25

20

15

10

5

0

-5 0 5 10 15 20

Unknown

∆Utotal

∆Urxn

Energetics of Individual Cell Failure

∆Utotal

∆Urxn

∆Utotal

∆Urxn

∆Utotal

∆Urxn

Fre

e E

nerg

y,

Q (

kJ/c

ell)

State of Charge, Q/Qmax (%)

LiMn2O4-

LiNiCoO2

LiCoO2

LiNiCoAlO2

Unknown

0

10

20

30

40

50

60

70

80

0 20 40 60 80 100 0

10

20

30

40

50

0 20 40 60 80 100

State of Charge, Q/Qmax (%)

Stored

Electrochemical

Energy (Q)

Total

Energy

(∆Utotal)

LiMn2O4-

LiNiCoO2

LiCoO2

LiNiCoAlO2

Unknown

Tota

l E

nerg

y, ∆

Uto

tal (

kJ/c

ell)

State-of-Charge is Not a Good Predictor of Energetics for

Different Chemistries and Cell Potentials

Li-Ion 18650 Batteries - Post Test

Zero Charge 50% Charged 100% Charged

Gravimetric Analysis for Volatile Yield

0

1

2

3

4

5

6

0 10 20 30 40 50

Vola

tile

Yie

ld,

g/c

ell

Electrochemical (Free) Energy, Q (kJ/cell)

• Bomb weighed before and after venting

to atmosphere to determine volatile yield

• Volatiles are combustible

• Yield Q

LiMn2O4-LiNiCoO2

LiCoO2

LiNiCoAlO2

Unknown

Infrared Spectra of Gaseous Decomposition Products

LiMn2O4-

LiNiCoO2

LiCoO2

LiNiCoAlO2

Unknown

Thermal Effects of Cell Failure

J.G. Quintiere & S.B. Crowley, Thermal Dynamics of 18650 Li-ion Batteries, The

Seventh Triennial International Fire & Cabin Safety Research Conference,

Philadelphia, PA, 2013.

20 g

2 s

600C

2 s

Separator

Melts (150C)

Venting (200C)

Failure (250C)

0

10

20

30

40

50

0 10 20 30 40 50

Therm

al E

nerg

y q

b, kJ/c

ell

Stored Free Energy, Q (kJ/cell)

1

1

Thermal Energy Release (qb) Free Energy (Q)

Implies chemical reactions of electrolytes

(∆Urxn) take place outside of cell when

contents are ejected

0

200

400

600

800

1000

1200

1400

0 20 40 60 80 100

Maxim

um

Cell

Surf

ace

Te

mpera

ture

, T

ma

x (C

)

State of Charge/SOC (%)

Tmax Tf Utotal

mcp

Tf Urxn

mcp

Q

mcp

Contents

Ejected,

∆Urxn 0,

Tmeas < Tcalc

Adiabatic (Surface) Temperature Rise

250CUrxn

mcp

Qmax

mcp

*SOC

100

Fire Calorimeter Testing of Lithium Cells

Special holder designed to

prevent rocketing of cell at failure

Standard ASTM E 1354 Operation

0

1

2

3

4

5

6

80 90 100 110 120 130 140 150

HR

R, kW

/cell

Elapsed Time, seconds

Original Data

HRR Corrected for 3-

second Response Time of

Cone Calorimeter

(Deconvoluted)

Heat Release Rate in Cone Calorimeter

5s

Venting

Failure

Failure is so rapid that HRR must be

corrected for cone calorimeter response

5s

5s

Flaming

Combustion of

Cell Contents

(75 kJ/cell)

Decomposition

Reactions

(14 kJ/cell)

Discharge of Stored

Electrochemical Energy

By Internal Short Circuit

(14 kJ/cell)

LiCoO2 Cell at 50% SOC

Fire and Thermal Hazards of 18650 Cell

Total 103 kJ/cell = 2.3 kJ/g 1/20 jet fuel

= 109 J/m3

75 kJ/cell

6.62 x 10-5 m3/ cell qv =

HRR (t ) qv

dV

dt qv

dL(t )3

dt 3qv (L0

)3t 2

Analytic Model of 18650 Cargo Fire Growth

L(t)

L(t)

L(t)

Combustion

Volume at time t,

V(t ) = L(t )3

L (18mm)(65mm) 34mmEffective Length of 18650,

Constant linear fire growth rate,

L 0 L

L 2

mc / 3x104 m /s

Heat Release in Flaming Combustion, qv = 109 J/m3

0

200

400

600

800

1000

1200

0 10 20 30 40 50 60 70

Heat R

ele

ase R

ate

, H

RR

(kW

)

Time After First Ignition, minutes

Battery Fire t 2 Model

(LiCoO2 18650, 50% SOC)

Full Scale Test Data

LiCoO2 18650, 50% SOC

(from O2 consumption)

H. Webster, May 2013

Full-Scale Test (Before) Full-Scale Test (After)

Model Versus Full Scale Test Data

Class E

Main Deck

Cargo

State-of-charge is a poor predictor of fire hazard for

different batteries and cell chemistries.

Total energy at failure of Li Ion cells/batteries (LIB), ∆Utotal

is almost twice the stored electrochemical energy Q for

the 18650 cell chemistries of this study.

Summary