reliability testing of na-metal halide, fe-ni, and pb acid

Reliability Testing of Na-Metal Halide, Fe-Ni,

and Pb Acid Batteries/Modules

Guosheng Li, Edwin C. Thomsen,

Nimat Shamim, Vilayanur V.

Viswanathan, and David M. Reed

Battery Materials and Systems Group

Pacific Northwest National Laboratory

2

Battery Reliability Laboratory at PNNL

• Aim to develop an advanced battery testing laboratory to help end-users better understand long term performance and reliability of emerging energy storage systems.

• Create innovative material solutions to existing technologies to increase reliability by understanding Materials-Performance relations for various battery technologies

• Provide battery operation guidelines and independent validation of performance to end users to maximize battery lifetime

3

Reliability Test Laboratory at PNNL

Energy Storage Technologies

• Vanadium Flow Batteries

UET: Mixed Acid

Storion: Bi-additive

• Li-ion

All cell: NMC

Iron Edison: LFP

• Pb Acid

RSR Technologies

C&D Technologies

BAES

• Na metal halide

FZSoNick

• Fe-Ni

Iron Edison

• Saltwater

Bluesky

• Ni-Zn

NGK Insulators

NGK Insulators

Iron Edison

Li ion cells

4

Reliability Test Laboratory

❑Module Testing:

o NHR Cycler 9 Channels 120V DC 200A (Regenerative)

o Arbin Cycler 16 Channels 60V DC 50A

o Arbin Cycler 4 Channels 100V DC 200A

o Modules up to 30 kWh

❑Single Cell Testing:

o Arbin Cycler (~400 channels)

❑Environmental Chamber:

o CSZ Chamber (3)

NHR Arbin

Arbin

5

Na-Metal Halide (ZEBRA) Testing

Nominal Voltage, V 48

Module Energy, kWh 9.6

Module Capacity, Ah 200

Weight, lb. 231

Dimension, inch 19.5(w) × 21.9(d) × 12.6(h)

Internal Temperature, oC 265 – 350

Environment Temperature, oC -40 – 60

48TL200 (FzSoNick)

Overall Redox Reaction:

2Na + MCl2 (Charge) 2NaCl + M (Discharge), where M= Ni, Fe

E0= 2.58 V for Ni; 2.35 V for Fe

Shamim et al. Materials (under review)

Thermal image

6

Testing Results with Default Cycle

0 100 20045

50

55

Voltage

Current

SOC (Ah)

Vo

lta

ge

(V

)

-40

0

40

Cu

rre

nt

(A)

CC Charge CV Charge

11.2 h

Charge: CC (40 A) + CV (53.7 V) Discharge: CC (40 A), 42 V

0 100 200260

280

300

Temperature

SOC (Ah)

Tem

pera

ture

(C

)265 C

BMS heater ON

0 50 100 150 200

260

280

300

Temperature

DOD (Ah)

Tem

pera

ture

(C

)

265 C margin

0 100 200

45

50

Voltage

Current

DOD (Ah)

Voltage (

V)

4.8 hr Discharge

-40

-20

0

20

40

Curr

ent (A

)

∆G= ∆H - T∙∆S

Hr = -T∙∆S (reversible heat)

∆S = -23.3 kJ/mol

Charge process: Endothermic process (T decreasing)

Discharge process: Exothermic process (T increasing)

NHR charge energy, kWh 10.99

Discharge energy, kWh 9.0

Charge efficiency, % 91.1

Discharge efficiency, % 98.8

Battery efficiency, % 90.0

Overall efficiency, % 80.9


7

Peak Shaving Tests

ProtocolsCharge

(hr)

Hold

(hr)

Discharge

(hr)

Hold

(hr)

6h PS 12 (CC+CV) 3 6 3

4h PS 12 4 4 4

2h PS 12 5 2 5

Peak Shaving Protocols

Protocols 6h PS 4h PS 2h PS

NHR discharge power, kW 1.25 1.875 3.75

Charge efficiency, % 81.1 81.3 85.0

Battery efficiency, % 90.0 88.6 83.6

Discharge efficiency, % 98.3 99.1 99.6

Overall efficiency, % 71.8 71.4 70.7

15 20 25

-80

-40

0

Curr

ent (A

)

Time (h)

2h PS

4h PS

6h PS

5h hold

4h hold

3h hold6 h

4h

2h

15 20 25250

300

350

Tem

pera

ture

(C

)

Time (h)

2h PS

4h PS

6h PS

3h hold

4h hold

5h hold333.7oC

296oC

278.5oC

❑ More energy loss due to the added holding time.

❑ Recuperate some of energy loss at 2h PS.

7.0 7.5 8.0 8.5 9.050

75

100

Eo

Ed

Eb

Ec

Energ

y E

ffic

iency (

%)

Discharged Energy (kWh)

6h PS

7.0 7.5 8.0 8.5 9.0250

275

300

Tem

pera

ture

(oC

)

Discharged Energy (kWh)

TEOD

TEOD-hold265oC

6h PS

❑ Higher efficiency with increasing energy utilization


8

Long-term PS and Other Tests

0 50 100 150 2000

50

100

150

200S

OC

(A

h)

Cycle Number

EOC

EOD

6h PS (7.5 kWh)

0 50 100 150194

196

198

200

202

SOC at 12 hr

Linear fit

SO

C (

Ah)

Cycle Number

Degradation rate:

0.0046%/cycle

Initial capacity (200 Ah)

10 11 12 13 14190

195

200

205

210

SO

C (

Ah)

Time (h)

1st cycle

50th

100th

150thEOC

0 5 10 15 20 250

50

100

150

200

SO

C (

Ah)

Time (h)

1st cycle

50th

100th

150th

Charge (CC+CV) Discharge

EOC-hold EOD-hold

Warming up

Long-term PS (6h PS at 7.5 kWh)

0 5 10

0

2

4

6

Energy

Temperature

Linear fit

Time (h)

Energ

y (

kW

h)

Heating up: 0.41 kWh/hr0

100

200

300

Tem

pera

ture

r (o

C)

265oC

NaAlCl4 Melting~160oC

0 20 40 60 80 100

0

50

100

150

200 SOC

Linear fit

Temp

Standby Time (hr)

SO

C (

Ah)

~2.15Ah/hr (~ 112 Wh/hr)

~265oC

200

250

300

Tem

pera

ture

(oC

)

Standby


oThe module exhibited a capacity degradation rate of 0.0046%/cycle

over 150 cycles (>150 days).

9

Fe-Ni Single Cell and Module Testing

Hydrogen evolution:

o Fe(OH)2 + 2e- Fe + 2OH-, -0.88 V vs SHE

o 2H2O + 2e- H2 + 2OH-, -0.83 V vs SHE

E0= 1.37 V

Shukla et al. J. Power Sources 100, 125 (2001)

100 Ah cell:

• 11,000 cycles at 80% DoD

• 30 years

• -30C to 60C

• 1% per day self-discharge

• Frequent watering

• Low energy density (~20

Wh/kg)

• Primary use for off-grid

• Applying peak shaving and frequency regulation protocols for single cell unit (100 Ah/cell) testing.

• Testing a serially connected battery module (1 kWh/module, 10-cell string) for various grid applications.

Iron Edison

10

Single Cell Testing for Fe-Ni Cell

Charging protocols from the Vendor (Similar to Pb acid)

1. Bulk Charge (CC) until 1.65 V

2. Absorption Charge (CV) at 1.65 V for 5 hrs

3. Discharge rate at C/20 − C/2

0 1 2 3 4 5 6 7

0

50

100

150

Absorption Time (hr)

Capacity (

Ah)

Charge

Discharge

Energy efficiency

0

50

100

Effic

iency (

%)

Charge: 25 A/1.65 V

Discharge: 25 A (C/4)

0 10 20 30 40

0

50

100

150

Overcharge (%)

Capacity (

Ah)

Energy Efficiency

Charge

Discharge

Charge: 25 A/1.65 V

Discharge: 25 A

0

50

100

Coulo

mbic

Effic

iency (

%)

0 10 20 30

0

1

2

3

4

5

Capacity D

ecay (

%/c

ycle

)

Overcharge (%)

Vendor’s protocol Modified protocol

0 50 100

0

50

100

150

Cycle number

Capacity (

Ah)

Efficiency

Charge

Discharge

Single cell

Charge: 25 A/1.65 V

Overcharge: 30%

Discharge: 25 A

Degradation:

0.003%

0

50

100

Coulo

mbic

Effic

iency (

%)

Manuscript in preparation

11

Testing for Grid Applications

Testing Protocols (PS):

• Charge: CC (40 W) + CV (1.65 V, 30% overcharge)

• Discharge: 2, 4, and 6h PS

• Energy utilization: 60, 80, and 100 Wh

60 80 10050

55

60

65

2h PS

4h PS

6h PSEn

erg

y E

ffic

ien

cy (

%)

Discharged Energy (Wh)

0 5 10 15

0

50

100

150

200

Cycle number

Energ

y (

Wh)

Charge

Discharge

Efficiency

0

50

100

Effic

iency (

%)

Single cell

Charge: 40W/1.65 V

Discharge: 100 Wh (6 hrs)

30% overcharge

0 5 10 15

0

500

1000

1500

2000

Cycle number

Ca

pa

city (

Ah

) Efficiency

Charge

Discharge

10-cell String

Charge: 400 W/1.65 V

Discharge: 1000 Wh(6 hrs)

Overcharge: 30%

0

50

100

Effic

ien

cy (

%)

• Similar performances of PS test for single cell vs 10-cell string.

• Higher overall efficiencies for longer discharge time.

• Frequency regulation test is underway…Manuscript in preparation

12

Pb Acid Testing

❑ Vendor: C&D Technologies

❑ Type: Valve Regulated Lead Acid

Battery

❑ Number of modules : 4

❑ Nominal Voltage: 14.1 VDC

(2.35V/cell)

❑ Module Capacity: 172 Ah

(C/10,1.8V@25℃)

❑ Dimension: 22(L) x 5(W) x 13(h)

❑ Vendor: BAE

❑ Type: Vented Lead Acid Battery



(2.4V/cell)

❑ Module Capacity: 167 Ah (C/10,1.8V)

❑ Electrolyte: Sulfuric acid with a

density of 1.24 kg/l at 20 °C (68 °F)

❑ Vendor: BAE

❑ Type: Valve Regulated Lead Acid

Battery



(2.35V/cell)

❑ Module Capacity: 182 Ah (C/10,1.8V)

❑ Electrolyte: Sulfuric acid with a

density of 1.24 kg/l (20 °C), fixed as

GEL by fumed silica

13

Pb Acid Battery Testing for PS and FR

❑ C&D Batteries are being tested at 2 peak shaving conditions

and to 2 frequency regulation conditions.

❑ Peak shifting done at C/2 and C/8 discharge current rate at

50% DOD from 100% SOC to 50% SOC

❑ Frequency regulation done at the same maximum power level

at 57-37% SOC and 80-60% SOC

0 400 800 120060

80

100

120

C/2 rate

C/8 rate

RT

E_

Wh

(%)

No. of Cycle

0 100 200 300

85

90

95

100

(80-60)% FR Cycle

(57-37)% FR Cycle

RT

E_

Wh

(%

)

No. of Cycles

❑ Capacity loss can be observed with increasing

duration.

❑ RTE has remained almost same throughout the

cycles.

❑ Recovery in capacity is probably associated with

the reconversion of PbSO4 back to Pb at negative

and PbO2 at positive electrodes.

0 4 8 12 16 20 2460

80

100

120

140

160

180

200

Dis

ch

arg

e c

ap

ac

ity

(A

h)

Month

PS(C/2)

PS(C/8)

FR(80-60)%

FR(57-37)%

14

Vanadium Redox Flow Battery (VRFB) System

❑UET Mixed-Acid VRFB

▪ 8 kW/30 kWh

▪ Operating Voltage: 40 - 65 V

❑Storion Bi-additive VRFB

▪ 3 kW/6 kWh

▪ Bi-additive Vanadium electrolytes

▪ Operating Voltage: 22 - 33 V

UET Storion

15

VRFB Initial Tests

4 6 8 1030

35

40

Efficiency

Energy

Discharge Power (kW)

Energ

y (

kW

h)

UET (8 kW/30 kWh)

Charge: 8 kW

70

80

90

100

Effic

iency (

%)

Charge: 8 kW (~C/4)

Discharge : 4.4 – 9.7 kW (~ C/7 – C/3)

0 1 2 3 40

5

10

Charge/Discharge Power (kW)

Energ

y (

kW

h)

Storion

3 kW/6 kWhEnergy

Efficiency

70

80

90

100

Effic

iency (

%)

Charge/Discharge: 1 – 3 kW (C/6 – C/2)

• Testing under peak shaving and frequency regulation protocols

• Long-term stability and reliability

• Long duration testing

16

Acknowledgments

DOE ‒ Office of Electricity

Thank You!

reliability testing of na-metal halide, fe-ni, and pb acid

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