Battery Management for Monitoring up to Battery Management for Monitoring up to
Six LeadSix Lead--Acid Batteries at the Individual Acid Batteries at the Individual
Dr. David Liu, PhDDr. David Liu, PhD
PHM Society PHM Society
BMS WorkshopBMS Workshop
September 26, September 26, 20112011
Six LeadSix Lead--Acid Batteries at the Individual Acid Batteries at the Individual
Battery and System LevelsBattery and System Levels
OverviewOverview
• Why Do We Need a Battery Fuel Gauge?
• Capabilities and Benefits of HDM BFG Technology
• BFG Application Examples
• BFG Configurations
22
• BFG Configurations
• HDM’s BFG Dual Tracking Methodology
• BFG Highlights Effects of Unhealthy Batteries on the Bank
• Re-Cap
Information is PowerInformation is Power
33
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?
Capabilities of HDM BFG TechnologyCapabilities 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)
44
– 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
Benefits of HDM BFG TechnologyBenefits of HDM BFG Technology
• Operations– Alerts crew when re-charging is necessary
– Provides Hours Remaining for silent watch
– Ensures mission capacity and success
55
• 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
BFG ImplementationBFG Implementation
Mobile ApplicationMobile Application
• Customer
– Navistar Defense
• UK MOD/NATO
• Vehicle
– Husky Tactical Support Vehicle
66
– 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
BFG ImplementationBFG Implementation
Stationary ApplicationStationary Application
• Customer – Raytheon Company
• System– R-Series Regenerator Hybrid
Power System
77
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
Battery Fuel Gauge Configurations
88
Battery Fuel Gauge Configurations
Configuration 1 Configuration 1
System Level Monitoring OnlySystem Level Monitoring Only
12VDC
Battery
#3
12VDC
Battery
#1DC
Ch
a(A
lte
12VDC
Battery
#5
Interface Connection
Inline Fuse
Battery Positive Sense Wire
99
Advantage: SIMPLICITY
12VDC
Battery
#4
12VDC
Battery
#2
Lo
ad
arg
er
ern
ato
r)
12VDC
Battery
#6
Batt
Neg
Load
Neg
Interface Connection(Display, RS232, CAN-Bus)
Fuel Gauge Sensor Module
Battery Negative Connection
Load Negative Connection
Configuration 2Configuration 2
Cell Level Monitoring OnlyCell Level Monitoring Only
12VDCBattery
#3
12VDCBattery
#1
BattNeg
LoadNeg
BattNeg
LoadNeg
DC
Ch
a(A
lte
12VDCBattery
#5
BattNeg
LoadNeg
Inline Fuse
Battery Positive Sense Wire
DA TA REA DING S
SO H Cell
SO C Cell
V (Voltage) Cell
1010
Advantage: PRECISION
12VDC
Battery
#4
12VDC
Battery
#2
Batt
Neg
Load
Neg
Batt
Neg
Load
Neg
Load
arg
er
ern
ato
r)
12VDC
Battery
#6
Batt
Neg
Load
Neg
Interface Connection
(Display, RS232, CAN-Bus)
Fuel Gauge Sensor Module
Battery Negative Connection
Load Negative Connection
V (Voltage) Cell
HR (H r Rem ain) Cell
I (Current) Cell
Tem p Cell
Configuration 3Configuration 3
System/String/Cell Level MonitoringSystem/String/Cell Level Monitoring
12VDC
Battery
#3
12VDC
Battery
#1DC
Ch
(Alt
12VDC
Battery
#5 Inline Fuse
Battery Positive Sense Wire
DATA READINGS
SOH
SOC Cell/String/System
V
Cell/String/System
Cell/System
1111
Advantage: SIMPLE, PRECISE & COST-EFFECTIVE
12VDC
Battery
#4
12VDC
Battery
#2
C L
oad
harg
er
tern
ato
r)
12VDC
Battery
#6
Batt
Neg
Load
Neg
Interface Connection
(Display, RS232, CAN-Bus)
Fuel Gauge Sensor Module
Battery Negative Connection
Load Negative Connection
V (Voltage)
HR (Hr Remain)
I (Current)
Temp
Cell/System
System
Cell/String/System
System
HDM’s Battery Fuel Gauge Technology:
1212
HDM’s Battery Fuel Gauge Technology:
Dual Tracking Methodology
SOC Measurement SOC Measurement
Using Dual Tracking MethodUsing Dual Tracking Method
60
80
100
SO
C (
%)
Fuel Gauge SOC
Theoretical SOC
Fuel Gauge SOH:82% (at discharging time = 0 min.)
1313
SOC Accuracy at 95%
0
20
40
0 10 20 30 40 50 60 70 80 90 100
SO
C (
%)
Discharging Time (min)
What is Dual Tracking Methodology?What is Dual Tracking Methodology?
1414
Template for Template for InitialInitial
II--SOC and VocSOC and Voc--SOC EstimationSOC EstimationSegments Voc AH SOC (%)
1 > 12.8 2 100-98
2 12.80-12.74 2 98-96
3 12.74-12.69 2 96-94
4 12.69-12.66 2 94-92
. . . .
1515
.
.
.
.
.
.
.
.
.
.
.
.
48 11.14-11.08 2 6-4
49 11.08-10.88 2 4-2
50 10.88-10.64 2 2-0
Total Segments: 1-50 Voc: >12.8 to 10.64 Total AH: 100 SOC: 100%-0%
I-SOC = AHremaining – AHdischarge
Total Initial AH
Template for Template for SelfSelf--Calibrated Calibrated
II--SOC and VocSOC and Voc--SOC EstimationSOC EstimationSegments Voc AH SOC (%)
1 > 12.8 1.8 100-98
2 12.80-12.74 1.8 98-96
3 12.74-12.69 2.1 96-93
4 12.69-12.66 2.1 93-90
. . . .
1616
.
.
.
.
.
.
.
.
.
.
.
.
48 11.14-11.08 1.6 6-4
49 11.08-10.88 1.6 4-2
50 10.88-10.64 1.8 2-0
Total Segments:
1-50
Voc:
>12.8 – 10.64
Self-Calibrated
Total AH: 90
SOC:
100%-0%
I-SOC = AHremaining – AHdischarge
Total Self-Calibrated AH
Error from CurrentError from Current--Based TrackingBased Tracking
60
80
100
SO
C (
%)
Charge/Discharge Cycling Fuel Gauge SOC
Overestimated
Accurate
Underestimated
1717
Lack of precise charge and discharge efficiency information results in accumulation of SOC estimation errors
0
20
40
0 50 100 150 200 250 300 350 400 450 500
SO
C (
%)
Discharging Time (min)
Error from VoltageError from Voltage--Based TrackingBased Tracking
24
25
26
27
Voc (Voltage)
Vo
c (
Vo
lts)
B (78%SOC)
A (100%SOC)
1818
Lack of voltage relaxation results in SOC errors
21
22
23
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90
time(mins)
Voc (Voltage)
Voc 12Hrs Rest after Full Charge
Voc No Rest after Full Charge
Time (min)
Vo
c (
Vo
lts)
Dual Tracking MethodologyDual Tracking Methodology
60
80
100
SO
C (
%)
Combined SOC
Voltage-based SOC
(%)
Voltage-Based Tracking SOC
1919
Dual Tracking Method is optimal for all loading conditions
0
20
40
0 50 100 150 200 250
SO
C (
%)
Discharging Time (min) Discharging Time (min)
SO
C
Dual Tracking SOC
Configuration 3Configuration 3
System/String/Cell Level MonitoringSystem/String/Cell Level Monitoring
12VDC
Battery
#3
12VDC
Battery
#1DC
L
Ch
ar
(Alte
rn
12VDC
Battery
#5
Interface Connection
Inline Fuse
Battery Positive Sense Wire
DATA READINGS
SOH
SOC Cell/String/System
V (Voltage)
Cell/String/System
Cell/System
2020
Advantage: SIMPLE, PRECISE & COST-EFFECTIVE
12VDC
Battery
#4
12VDC
Battery
#2
Lo
ad
rge
rn
ato
r)
12VDC
Battery
#6
Batt
Neg
Load
Neg
Interface Connection
(Display, RS232, CAN-Bus)
Fuel Gauge Sensor Module
Battery Negative Connection
Load Negative Connection
V (Voltage)
HR (Hr Remain)
I (Current)
Temp
Cell/System
System
Cell/String/System
System
BFG Detection of Unhealthy Battery: Cycle 1BFG Detection of Unhealthy Battery: Cycle 1
0
10
20
30
40
50
60
70
80
90
100
0 5 10 15 20 25 30 35
SO
C (
%)
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
SO
C(%
)
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
SO
C (
%)
Battery 2
Battery Monitor SOC
Theoretical SOC
Theoretical + 5%
Theoretical - 5%
60
70
80
90
100
SO
C (
%)
Battery Monitor SOC
Theoretical SOC
Theoretical + 5%
Theoretical - 5% 50
60
70
80
90
100
SO
C (
%)
Battery Monitor SOC
Theoretical SOC
Theoretical + 5%
Theoretical - 5%50
60
70
80
90
100
SO
C (
%)
Battery Monitor SOC
Theoretical SOC
Theoretical + 5%
Theoretical - 5%
2121
HDM BFG identifies
weak battery during
discharge cycle 1
0
10
20
30
40
50
0 5 10 15 20 25 30 35
SO
C (
%)
AH Discharged
Battery 4
Theoretical - 5%
0
10
20
30
40
50
0 5 10 15 20 25 30 35
SO
C (
%)
AH Discharged
Battery 6
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
0 5 10 15 20 25 30 35
SO
C (
%)
AH Discharged
Battery 5
Theoretical - 5%
Battery5
BFG Accuracy Established: Cycle 3BFG Accuracy Established: Cycle 3
0
10
20
30
40
50
60
70
80
90
100
0 5 10 15 20 25 30 35
SO
C (
%)
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
SO
C (
%)
Battery 2
Battery Monitor SOC
Theoretical SOC
Theoretical + 5%
Theoretical - 5%
70
80
90
100
Battery Monitor
Theoretical SOC
Theoretical + 5%70
80
90
100Battery Monitor SOC
Theoretical SOC
Theoretical + 5%70
80
90
100
SO
C (
%)
Battery Monitor SOC
Theoretical SOC
Theoretical + 5%
0
10
20
30
40
50
60
70
80
90
100
0 5 10 15 20 25 30 35 40
SO
C (
%)
Battery 3
Battery Monitor SOC
Theoretical SOC
Theoretical + 5%
Theoretical - 5%
2222
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 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
0 5 10 15 20 25 30 35
SO
C (
%)
AH Discharged
Battery 4
Theoretical + 5%
Theoretical - 5%
0
10
20
30
40
50
60
70
0 5 10 15 20 25 30 35 40
SO
C (
%)
AH Discharged
Battery 6
Theoretical + 5%
Theoretical - 5%
0
10
20
30
40
50
60
70
0 5 10 15 20 25 30 35
SO
C (
%)
AH Discharged
Battery 5
Theoretical + 5%
Theoretical - 5%
Effects of Unhealthy Battery on Bank 1*Effects of Unhealthy Battery on Bank 1*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
5 10.8V 0 50
2323
* 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
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%
Effects of Unhealthy Battery on Bank 2*Effects of Unhealthy Battery on Bank 2*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
5 11.2V 12 75
2424
* 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
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%
Weakest Battery Threshold Weakest Battery Threshold
vs. Conventional Threshold at 21Vvs. Conventional Threshold at 21VString
#
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 20A2 11.4V 11.1V
3 10.6V 9.6V
2525
By extending the system run-time (e.g. by 30 minutes), would be at the expense of the weakest battery
2
3 10.6V 9.6V
30A 6A 65A 3A4 12.1V 11.5V
3
5 11.2V 9.7V
36A 45A 17A 19A6 11.5V 11.3V
Sum
1 - 3
Sum
1 - 6
22.7V 21.0V 102A 102A 102A Set @ 42A
60
70
80
90
100
SO
C (
%)
Battery System Battery Monitor SOC
Theoretical SOC
Theoretical + 5%
Theoretical - 5%
System-Level Monitoring During Complete Charge-Discharge Cycles
2626
0
10
20
30
40
50
0 200 400 600 800 1000 1200 1400 1600 1800 2000
SO
C (
%)
AH Discharged/Charged
• SOC accuracy reaches 90-95% during the charge portion of the cycle within 3 cycles
Single BFG at 95% AccuracySingle BFG at 95% Accuracy
for up to 6 Individual Batteriesfor 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
2727
– 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)
Thank You!
Contact Information:
Dr. David Liu, VP of R&D: [email protected]
2828
Dr. David Liu, VP of R&D: [email protected]
HDM Systems, Inc.226 Lincoln StreetAllston, MA 02134Tel: 617.562.4054Fax: 617.562.4013
Web: www.HDM-Sys.com
AppendixAppendix
2929
AppendixAppendix
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
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 SOCTheoretical SOC
Fuel Gauge SOH: 89%
at Discharge Time = 0 min.
SOC Measured by DualSOC Measured by Dual--Tracking Method:Tracking Method:
Partial Discharge Partial Discharge –– Cycle 1 to Cycle 4Cycle 1 to Cycle 4
3030
0
0 20 40 60 80 100
Discharging Time (min)
0
0 20 40 60 80 100Discharging Time (min)
0
20
40
60
80
100
0 20 40 60 80 100
SO
C (
%)
Discharging Time (min)
3rd Discharge Cycle (100% to 50% SOC) (2x55AH 12V Batteries, 24V in Series, 10A/40A Alternating Loads)
Fuel Gauge SOC
Theoretical SOC
Fuel Gauge SOH: 86% at Discharge Time = 0
0
20
40
60
80
100
0 20 40 60 80 100
SO
C (
%)
Discharging Time (min)
4th Discharge Cycle (100% to 0% SOC) (2x55AH 12V Batteries, 24V in Series, 5A/40A Alternating Loads)
Fuel Gauge SOC
Theoretical SOC
Fuel Gauge SOH: 83% at Discharge Time = 0
SOC accuracy reaches 90-95% after four partial discharge cycles
50
60
70
80
90
100
SO
C (
%)
Battery H2
50
60
70
80
90
100
SO
C (
%)
Battery System
Partial Charge and Discharge Cycles Partial Charge and Discharge Cycles
of Battery Bankof Battery Bank
3131
SOC accuracy reaches 90-95% after four partial charge and
discharge cycles
0
10
20
30
40
50
0 50 100 150 200
SO
C (
%)
AH Discharged/Charged
0
10
20
30
40
50
0 100 200 300 400 500 600
SO
C (
%)
AH Discharged/Charged
BFG: Water Submersion Test
3232
BFG was submersed in water at 25°C for three
hours, and was tested for operational performance