Battery Management for Monitoring up to Six Lead-Acid ... · Battery Management for Monitoring up to Six Lead-Acid Batteries at the Individual Battery and System Levels . 2 ... Information

Dr. David Liu, PhD

NDIA Joint Service Power Expo

May 3, 2011

Battery Management for Monitoring up to

Six Lead-Acid Batteries at the Individual

Battery and System Levels

2

Overview

• Why Do We Need a Battery Fuel Gauge?

• Capabilities and Benefits of HDM BFG Technology

• BFG Application Examples

• BFG Configurations

• HDM’s BFG Dual Tracking Methodology

• BFG Highlights Effects of Unhealthy Batteries on the Bank

• Re-Cap

3

Information is Power

You would not drive a car

without a gas gauge…

Why would you execute a mission-critical

operation, such as “silent watch”,

without a Battery Fuel Gauge?

4

Capabilities of HDM BFG Technology

• Battery Power Usage Information: Diagnostics and Prognostics – State of Charge (SOC) at 95% Accuracy

– State of Health (SOH) at 95% Accuracy

– Hours Remaining (HR) at 90% Accuracy

– Battery Voltage (V)

– Battery Temperature (T)

– Current (I)

– State of Life (SOL)

• Functionality – System Interface: CANBUS, RS232, Control Panel-Mounted Display

– Real-Time Data and Estimations

– Self-Calibration

– Lightweight Packaging

5

Benefits of HDM BFG Technology

• Operations – Alerts crew when re-charging is necessary

– Provides Hours Remaining for silent watch

– Ensures mission capacity and success

• Maintenance – Identifies unhealthy batteries for replacement

– Facilitates Condition-Based Maintenance (CBM)

• Cost-Efficiency – Single BFG per system vs. multiple BFGs per system

– Simple configuration reduces install, operation, and maintenance

– Powerful tool for intelligent power management systems

6

BFG Implementation

Mobile Application

• Customer

– Navistar Defense

• UK MOD/NATO

• Vehicle

– Husky Tactical Support Vehicle

• Application

– Monitors Battery SOC and SOH

Over 1500 HDM BFGs have

been installed in Husky

TSVs in Afghanistan

supporting the NATO troops

7

BFG Implementation

Stationary Application

• Customer – Raytheon Company

• System – R-Series Regenerator Hybrid

Power System

• Application – USMC Experimental

Forward Operating Base Phase IV Demonstration in 2010 at 29 Palms, CA

HDM BFG is critical component

of intelligent Hybrid Power System

8

Battery Fuel Gauge Configurations

9

Configuration 1

System Level Monitoring Only

Advantage: SIMPLICITY

12VDC

Battery

#3

12VDC

Battery

#1

12VDC

Battery

#4

12VDC

Battery

#2

DC

Load

Charg

er

(Alte

rnato

r)

12VDC

Battery

#5

12VDC

Battery

#6

Batt

Neg

Load

Neg

Interface Connection

(Display, RS232, CAN-Bus)

Fuel Gauge Sensor Module

Inline Fuse

Battery Positive Sense Wire

Battery Negative Connection

Load Negative Connection

10

Configuration 2

Cell Level Monitoring Only

Advantage: PRECISION

12VDC

Battery

#3

12VDC

Battery

#1

12VDC

Battery

#4

12VDC

Battery

#2

Batt

Neg

Load

Neg

Batt

Neg

Load

Neg

Batt

Neg

Load

Neg

Batt

Neg

Load

Neg

DC

Lo

ad

Cha

rger

(Alte

rnato

r)

12VDC

Battery

#5

12VDC

Battery

#6

Batt

Neg

Load

Neg

Batt

Neg

Load

Neg




Inline Fuse




DATA READINGS

SOH Cell

SOC Cell

V (Voltage) Cell

HR (Hr Remain) Cell

I (Current) Cell

Temp Cell

11

Configuration 3

System/String/Cell Level Monitoring

Advantage: SIMPLE, PRECISE & COST-EFFECTIVE

12VDC

Battery

#3

12VDC

Battery

#1

12VDC

Battery

#4

12VDC

Battery

#2

DC

Lo

ad

Cha

rger

(Alte

rnato

r)

12VDC

Battery

#5

12VDC

Battery

#6

Batt

Neg

Load

Neg




Inline Fuse




DATA READINGS

SOH

SOC Cell/String/System

V (Voltage)

HR (Hr Remain)

I (Current)

Temp

Cell/String/System

Cell/System

System

Cell/String/System

System

12

HDM’s Battery Fuel Gauge Technology:

Dual Tracking Methodology

13

SOC Measurement

Using Dual Tracking Method

SOC Accuracy at 95%

0

20

40

60

80

100

0 10 20 30 40 50 60 70 80 90 100

SO

C (

%)

Discharging Time (min)

3rd Discharging Cycle (2x55 AH Batteries, 24V in series, 10A/40A Alternating Loads)

Fuel Gauge SOC

Theoretical SOC

Fuel Gauge SOH:82% (at discharging time = 0 min.)

14

What is Dual Tracking Methodology? START

Measure

• Battery Internal

Resistance (Ri)

• Voltage (VB)

• Discharge Current (I)

Open Circuit Voltage (VOC)

VOC = VB + I*Ri

Voltage-Based V-SOC

(from VOC vs. SOC Table)

Ah-Cumulative

Ah-Adjusted

Current Based

I-SOC

Integration

Combi-SOC

Corrections:

• Discharge Rate

• Temperature

• Self Discharge

Ah-Discharge and

Ah-Regeneration

Dual Tracking Voltage and Current Based SOC Derivation

Current-based SOC

(I-SOC)

Voltage-based SOC

(V-SOC)

15

Error from Current-Based Tracking

Lack of precise charge and discharge efficiency information results in accumulation of SOC estimation errors

0

20

40

60

80

100

0 50 100 150 200 250 300 350 400 450 500

SO

C (

%)


Charge/Discharge Cycling Fuel Gauge SOC

Overestimated

Accurate

Underestimated

16

Error from Voltage-Based Tracking

Lack of voltage relaxation results in SOC errors

Voc (Open Circuit Voltage) Profiles of Battery with and without

Resting

21

22

23

24

25

26

27

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90

time(mins)

Voc (

Volta

ge)

Voc 12Hrs Rest after Full Charge

Voc No Rest after Full Charge

A (100%SOC)

B (78%SOC)

25.5

Time (min)

Vo

c (

Vo

lts)

B (78%SOC)

A (100%SOC)

17

Dual Tracking Methodology

Dual Tracking Method is optimal for all loading conditions

0

20

40

60

80

100

0 50 100 150 200 250

SO

C (

%)


SOC Measurement in 24VDC Battery

with Partial Discharge / Partial Charge Conditions

Combined SOC

Voltage-based SOC


SO

C (

%)

Dual Tracking SOC

Voltage-Based Tracking SOC

18

Configuration 3

System/String/Cell Level Monitoring

Advantage: SIMPLE, PRECISE & COST-EFFECTIVE

12VDC

Battery

#3

12VDC

Battery

#1

12VDC

Battery

#4

12VDC

Battery

#2

DC

Lo

ad

Cha

rger

(Alte

rnato

r)

12VDC

Battery

#5

12VDC

Battery

#6

Batt

Neg

Load

Neg




Inline Fuse




DATA READINGS

SOH

SOC Cell/String/System

V (Voltage)

HR (Hr Remain)

I (Current)

Temp

Cell/String/System

Cell/System

System

Cell/String/System

System

19

BFG Detection of Unhealthy Battery: Cycle 1

HDM BFG identifies

weak battery during

discharge cycle 1

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25 30 35 40

SO

C (

%)

AH Discharged

Battery 1

Battery Monitor SOC

Theoretical SOC

Theoretical + 5%

Theoretical - 5%

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25 30 35 40

SO

C(%

)

AH Discharged

Battery 3

Battery Monitor SOC

Theoretical SOC

Theoretical + 5%

Theoretical - 5%

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25 30 35 40

SO

C (

%)

AH Discharged

Battery 2

Battery Monitor SOC

Theoretical SOC

Theoretical + 5%

Theoretical - 5%

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25 30 35 40

SO

C (

%)

AH Discharged

Battery 4

Battery Monitor SOC

Theoretical SOC

Theoretical + 5%

Theoretical - 5%

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25 30 35 40

SO

C (

%)

AH Discharged

Battery 6

Battery Monitor SOC

Theoretical SOC

Theoretical + 5%

Theoretical - 5%

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100

SO

C (

%)

AH Discharged

Battery System6 Batteries Combined

Battery Monitor SOC

Theoretical SOC

Theoretical + 5%

Theoretical - 5%

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25 30 35 40

SO

C (

%)

AH Discharged

Battery 5

Battery Monitor SOC

Theoretical SOC

Theoretical + 5%

Theoretical - 5%

Battery5

20

BFG Accuracy Established: Cycle 3

HDM BFG achieves

95% accuracy by

discharge cycle 3

(i.e. no adjustments needed)

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25 30 35 40

SO

C (

%)

AH Discharged

Battery 1

Battery Monitor SOC

Theoretical SOC

Theoretical + 5%

Theoretical - 5%

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100

SO

C (

%)

AH Discharged

Battery System6 Batteries Combined

Battery Monitor SOC

Theoretical SOC

Theoretical + 5%

Theoretical - 5%

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25 30 35 40

SO

C (

%)

AH Discharged

Battery 2

Battery Monitor SOC

Theoretical SOC

Theoretical + 5%

Theoretical - 5%

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25 30 35 40

SO

C (

%)

AH Discharged

Battery 4

Battery Monitor

Theoretical SOC

Theoretical + 5%

Theoretical - 5%

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25 30 35 40 45

SO

C (

%)

AH Discharged

Battery 6

Battery Monitor SOC

Theoretical SOC

Theoretical + 5%

Theoretical - 5%

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25 30 35 40

SO

C (

%)

AH Discharged

Battery 5

Battery Monitor SOC

Theoretical SOC

Theoretical + 5%

Theoretical - 5%

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25 30 35 40

SO

C (

%)

AH Discharged

Battery 3

Battery Monitor SOC

Theoretical SOC

Theoretical + 5%

Theoretical - 5%

21

Effects of Unhealthy Battery on Bank 1*

* Battery Bank 1: Optima Batteries

• String 3: Divergence of voltage and reduction in discharge current cause over-current stress on Strings 1 and 2

• Premature termination of discharge cycle, resulting in 19% loss in usable capacity

String # Battery # Individual Battery Voltage @

End Point

Discharge Current

From To

SOC

%

SOH

%

1

1 11.3V

12A 19A

10 73

2 11.5V 16 78

2

3 11.4V

10A 18A

12 71

4 11.4V 12 73

3

5 10.8V

18A 4A

0 50

6 12.0V 36 78

Sum

1 - 3

Sum

1 - 6

System Battery End Voltage:

22.8V

System Discharge Current:

~41A ~41A

0%

68%

22

Effects of Unhealthy Battery on Bank 2*

* Battery Bank 2: Hawker Batteries

• String 2: Divergence of voltage and reduction in discharge current cause over-current stress on Strings 1 and 3

• Premature termination of discharge cycle, resulting in 17% loss in usable capacity

String # Battery # Individual Battery Voltage @

End Point

Discharge Current From

To

SOC

%

SOH

%

1

1 11.3V

33A 49A

14 77

2 11.4V 19 80

2

3 10.6V

33A 6A

0 55

4 12.1V 51 93

3

5 11.2V

34A 45A

12 75

6 11.5V 22 87

Sum

1 - 3

Sum

1 - 6

System Battery End Voltage:

22.7V

System Discharge Current:

100A 100A

0%

62%

23

Weakest Battery Threshold

vs. Conventional Threshold at 21V

By extending the system run-time (e.g. by 30 minutes), would be at the expense of the weakest battery

String

#

Battery

#

Battery Voltage Discharge Current Charge Current

@ End Point 1

(Bat 3 SOC=0%)

@ End Point 2 (Bat

Voltage=21V)

@ 100%

SOC

@ End

Point 1

@ End

Point 2

@ Low SOC

1

1 11.3V 9.9V

36A

51A

20A

20A 2 11.4V 11.1V

2

3 10.6V 9.6V

30A

6A

65A

3A 4 12.1V 11.5V

3

5 11.2V 9.7V

36A

45A

17A

19A 6 11.5V 11.3V

Sum

1 - 3

Sum

1 - 6

22.7V 21.0V 102A 102A 102A Set @ 42A

24

Single BFG at 95% Accuracy

for up to 6 Individual Batteries

• Provides breadth and depth necessary for Cost-Effective

Battery Management Systems and CBM

• User Level

– Ensures power system reliability and performance

• Maintenance Level

– Enables precision pinpoint of unhealthy batteries for CBM

• Incorporates theoretically scalable algorithm, for banks

greater than 6 batteries (i.e. important for larger, stationary

energy storage systems)

25

Thank You!

Contact Information:

Dr. David Liu, VP of R&D: [email protected]

Tel: 617.562.4054

Grace Chu, Director of New Business Development: [email protected]

Tel: 617-306-0060

Jim Averill, Director of Sales: [email protected]

Tel: 617-333-0399

HDM Systems, Inc.

226 Lincoln Street

Allston, MA 02134

Tel: 617.562.4054

Fax: 617.562.4013

Web: www.HDM-Sys.com

mailto:[email protected]









http://www.hdm-sys.com/



26

Appendix

27

Dual Tracking: Battery 5 in Battery Pack 1,2,3,5

Cycles 1 to 4 4.20 2 H5 cycle 1

0

20

40

60

80

100

0 20 40 60 80 100 120

AH Discharged

SO

C (

%)

Battery Monitor SOC

Theoretical SOC

Theoretical + 5%

Theoretical - 5%

4.20.2 H5 cycle 2

0

20

40

60

80

100

0 20 40 60 80 100

AH Discharged

SO

C (

%)

Battery Monitor SOC

Theoretical SOC

Theoretical + 5%

Theoretical - 5%

4.20.2 H5 Cycle 3

0

20

40

60

80

100

0 20 40 60 80 100 120

AH Discharged

SO

C (

%)

Battery Monitor SOC

Theoretical SOC

Theoretical + 5%

Theoretical - 5%

4.21.1 H5

0

20

40

60

80

100

0 20 40 60 80 100

AH Discharged

SO

C (

%)

Battery Monitor SOC

Theoretical SOC

Theoretical + 5%

Theoretical - 5%

HAWKER 5

HAWKER 5 HAWKER 5

HAWKER 5

Cycle 1

Cycle 3 Cycle 4

Cycle 2

AHr Discharged AHr Discharged

AHr Discharged AHr Discharged

SO

C(%

)

SO

C(%

)

SO

C(%

)

SO

C(%

)

In a battery pack, HDM’s BFG provides accurate SOC & SOH

information within 2-3 cycles in a battery pack

28

0

20

40

60

80

100

0 20 40 60 80 100

SO

C (

%)


Initial Discharge Cycle (100% to 50% SOC) (2x55AH 12V Batteries, 24V in Series, 10A/40A Alternating Loads)

Fuel Gauge SOC

Theoretical SOC

Fuel Gauge SOH: 95% at Discharge Time = 0

0

20

40

60

80

100

0 20 40 60 80 100

SO

C (

%)


2nd Discharge Cycle (100% to 50% SOC) (2x55AH 12V Batteries, 24V in Series, 10A/40A Alternating Loads)

Fuel Gauge SOC

Theoretical SOC

Fuel Gauge SOH: 89%

at Discharge Time = 0 min.

0

20

40

60

80

100

0 20 40 60 80 100

SO

C (

%)


3rd Discharge Cycle (100% to 50% SOC) (2x55AH 12V Batteries, 24V in Series, 10A/40A Alternating Loads)

Fuel Gauge SOC

Theoretical SOC


0

20

40

60

80

100

0 20 40 60 80 100

SO

C (

%)


4th Discharge Cycle (100% to 0% SOC) (2x55AH 12V Batteries, 24V in Series, 5A/40A Alternating Loads)

Fuel Gauge SOC

Theoretical SOC


SOC Measured by Dual-Tracking Method Scenario 2: Partial Discharge – Cycle 1 to Cycle 4

SOC error is within 5% at cycle 4

29

Partial Charge/Discharge Cycles of Battery Bank 2 – Battery #2/System

•SOC accuracy is 95% after four partial charge and

discharge cycles

0

10

20

30

40

50

60

70

80

90

100

0 50 100 150 200

SO

C (

%)

AH Discharged/Charged

Battery H2

0

10

20

30

40

50

60

70

80

90

100

0 100 200 300 400 500 600

SO

C (

%)


Battery System

30

0

10

20

30

40

50

60

70

80

90

100

0 200 400 600 800 1000 1200 1400 1600 1800 2000

SO

C (

%)


Battery System Battery Monitor SOC

Theoretical SOC

Theoretical + 5%

Theoretical - 5%

Whole Battery Bank (6 Batteries) Monitoring

• SOC accuracy is 20% in first cycle, it quickly improves to 5% within a

few cycles

•Total AH discharge is measured around 200 AH

•System discharge termination point: is set when any battery in the

system reaches a low voltage of 10.5V

31

• Battery #3 is the weakest. SOH ~ 50%, other batteries are 75% to 80%

• At 1st cycle, SOC of battery #3 is 40%. After a few cycles, SOC is within

5% error

•Battery #3 capacity is only 50Ah and is fully utilized when the system

reaches the termination point

•Battery #4 in the same string only used up 50% capacity when system

reaches the termination point

0

10

20

30

40

50

60

70

80

90

100

0 100 200 300 400 500 600 700 800

SO

C (

%)


Battery H3 Battery Monitor SOC

Theoretical SOC

Theoretical + 5%

Theoretical - 5%

0

10

20

30

40

50

60

70

80

90

100

0 100 200 300 400 500 600 700 800

SO

C (%

)


Battery H4 Battery Monitor SOC

Theoretical SOC

Theoretical + 5%

Theoretical - 5%

5-Cycle-Profile of 2nd String of Batteries (3&4)

32

Bad battery causes battery voltage divergence

in a battery pack

Voltage vs. Discharge Time of Battery Pack 1,2,3,5

Cycle 1

4.20.2 H1 cycle 1

10

10.5

11

11.5

12

12.5

13

0 10 20 30 40 50 60 70


Vo

ltag

e (

V)

4.20.2 H2 cycle 1

10

10.5

11

11.5

12

12.5

13

0 10 20 30 40 50 60 70


Vo

ltag

e (

V)

4.20.2 H3 Cycle1

10

10.5

11

11.5

12

12.5

13

0 10 20 30 40 50 60 70


Vo

ltag

e (

V)

4.20.2 H5 cycle 1

10

10.5

11

11.5

12

12.5

13

0 10 20 30 40 50 60 70


Vo

ltag

e (

V)

HAWKER 2 HAWKER 5

Discharge Time (min)

Vo

ltag

e(V

)

HAWKER 1

Vo

ltag

e(V

)

Vo

ltag

e(V

) V

olt

ag

e(V

)




HAWKER 3

33

Current vs. Discharge Time of Battery Pack 1,2,3,5

Cycle 1

Bad battery causes discharging currents unbalanced

between battery strings (1&2) vs. (3&5)

4.20.2 H1 cycle 1

-100

-80

-60

-40

-20

0

0 10 20 30 40 50 60 70


Cu

rren

t (A

)

4.20.2 H2 cycle 1

-100

-80

-60

-40

-20

0

0 10 20 30 40 50 60 70


Cu

rren

t (A

)

4.20.2 H3 Cycle 1

-100

-80

-60

-40

-20

0

0 10 20 30 40 50 60 70


Cu

rren

t (A

)

4.20.2 H5 cycle 1

-100

-80

-60

-40

-20

0

0 10 20 30 40 50 60 70


Cu

rren

t (A

)

Discharge Time (min) Discharge Time (min)

Discharge Time (min) Discharge Time (min)

Cu

rren

t(A

)

Cu

rren

t(A

)

Cu

rren

t(A

)

Cu

rren

t(A

)

HAWKER 1

HAWKER 2

HAWKER 3

HAWKER 5

34

BFG: Water Submersion Test

BFG was submersed in water at 25°C for three hours,

and was tested for operational performance

Documents

Battery Management for Monitoring up to Six Lead-Acid ... · Battery Management for Monitoring up to Six Lead-Acid Batteries at the Individual Battery and System Levels . 2 ... Information