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How reliable are theoretical battery lifetime calculations compared with reality? The Dutch DSO’s Netherlands (within Netbeheer Nederland), joined forces to carry out a unique study of the predicted and actual battery lifetime. In this study, batteries were examined from gas meters that had already been operating for 4-5 years. The results were promising: after 4-5 years: the actual (practical) lifetime of the batteries examined turned out to be in line with the predicted (theoretical) values.
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Technology Center10 October 2012Machiel Joosse (DNWB) / Horst Reuning (Tadiran)Version: 1.2
Battery research studyHow reliable are theoretical battery lifetime calculations
compared with reality?
In cooperation with:
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Agenda:
Introduction Machiel Joosse (Netbeheer NL) Horst Reuning, Tadiran Netbeheer NL
Reason to start battery study Project approach
Used cases / pilot meters Project time line / actions
Calculation model power consumption Lithium-thionyl chloride batteries (Li-SOCl2) Lifetime calculation model Explanation:
residual discharge Titration
Results Conclusions
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Situation Netbeheer Netherlands Netbeheer NL is a cooperation of Dutch grid
operators:
Works together on Smart Metering, driven by the steering committee pgASM
Battery study team: Ben Deibel; Alliander Clemens van den Berghe ; Stedin Eelco Klaver; Enexis Leo Kramp; Stedin Machiel Joosse ; DNWB (project leader)
Structure Netbeheer Nederland
Cluster
Strategy &
Innovation
Cluster
Realization
Cluster
Analysis &
Design
pgASM (program board Smart Meter Rollout)
cluster
Vision
development
..
Battery
study
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..Privacy &
Security..
Smart
Buying
..
..
DSMR
..
..
BRIER
..
..Currently 21 running projects
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Reason to start battery study:
One requirement
“We require a (battery) life time
of 20 years!”
Many concerns
“My batteries are always emtpy after 6 months”
“20 years? … My gut feeling says… :IMPOSSIBLE!”
“What aboutreliability???”
I do not believe suchlife time calculations
“Idea: Lets investigate
5 years old meters…”
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Project approach (1/3); different cases:Grid company Meter supplier Case Period
installed in field
Total investigatedby Tadiran
Guaranteedlifetime (at hourly reading)
Pre NTAWired M-Bus
New on stock since 2007
None7x Residual discharge
15 years
Readout interval:1x per hour
Oct 2007-Apr 2012(56 Months)
20x Residual 5x Titration
15 years
Readout interval:180x per hour(each 20 sec)
May 2008 –May 2012(48 Months)
20x Residual 5x Titration
15 years
Pre NTAWireless M-Bus Transmit
interval:4x per hour
Oct 2008 –May 2012(43 Months)
20x Titration 15 years
Pre NTATransmit interval:1x per hour
May 2007 -May 2012(60 Months)
10x Residual10x Titration
10 years
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“Idea: Lets investigate
5 years old meters…”
Evaluation
& sharing
results
Defining
expected
capacity
= Flonidan / L+G
= Tadiran
= NBNL
= NBNL+ Flonidan / L+G
TitrationTitration
Measuring
power consumption
of electronics
Project approach (2/3); project time line
results
Residual
dischargeBatteries
Tadirangathering
meters
Start
Project
Actions done by:
= NBNL, Flonidan, L+G and Tadiran
PID
Dec 2011 July 2012
7 August 2012 11 Sept 2012
Today:
Presentation: Battery research
study
@
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Measuring power consumption of electronics
Gas meters electronics investigated to see if: does the component aging influence the energy usage? does the measured energy usage reflect the original values in the life time
calculation?
Used instruments:
1) Digital Multi Meter: Voltcraft VC940- to measure idle current -
2) USB oscilloscope: Handyscoop HS3- to measure current peaks / profile -
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Calculation model power consumption:
Impression measurement setupFlonidan G4SRV at Enexis
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Project approach (3/3); To get manufacturer independent results :
Batteries were uniquely marked, which correspond with original meter number
Tadiran received batteries, pilot cases and field installation dates were not provided.
After determining remaining capacity the Pilot cases, install date etc. were shared.
Columns not shared
Shared columns
Battery Investigations
Tadiran Batteries GmbH
Horst Reuning
Tadiran Batteries GmbH Germany, Horst Reuning, for Netbeheer project
Different Primary Battery Systems
1 Li/SOCl21280 Wh/dm3 hermetically welded2 Li/MnO2580 Wh/dm3 crimped elastomer seal or hermetically welded3 Alkaline280 Wh/dm3 crimped elastomer seal
Tadiran Batteries GmbH Germany, Horst Reuning, for Netbeheer project
The Lithium / Thionyl Chloride Battery System
4 High cell voltage: 3.6 V4 Highest energy density: 680 Wh/kg
4 Wide temperature range: –55°C up to +130°C 4 Low self discharge: <1% p.a. at 25°C
Tadiran Batteries GmbH Germany, Horst Reuning, for Netbeheer project
Life Time Calculation
4 Required:• Minimum Voltage• Temperature range• Current profile, inlcuding peak currents and current cycles
4 Basis: discharge results, obtained• over more than 10 years real time discharge• at different temperatures• under different load profiles
4 Calculation model takes into account:• Self discharge rates• Impedance loss (growth of internal resistance)
Tadiran Batteries GmbH Germany, Horst Reuning, for Netbeheer project
Operating Life & Self Discharge StudyMicrocalorimetry
Tadiran Batteries GmbH Germany, Horst Reuning, for Netbeheer project
Operating Life & Self Discharge Study
Tadiran Batteries GmbH Germany, Horst Reuning, for Netbeheer project
D-size cell, XOL seriesDischarge curves @RT
Nominal vs. Available Capacity SL-860
Tadiran Batteries GmbH Germany, Horst Reuning, for Netbeheer project
Assessment of Batteries Returned from the Field
4 After use in gas meters for approx. 5 years4 Determination of residual capacity
4 Assessment Method 1: Discharge• AA size cells: 1800 Ω to 2 Volts (ca. 2 mA)• D size cells: 560 Ω / 180 Ω to 2 Volts (ca. 6 mA / 20 mA)
4 Assessment Method 2: Titration• Cut cell open• Remove current collector, cathode, separator• Dissolve residual anode material in water• Neutralize by addition of hydrochloric acid (HCl)• Use an indicator to determine the turnover point• Calculate the amount of residual metallic lithium.
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Results
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Results (1/3); Case Stedin / L+G - L+G E6V -
Note: discharged in 2steps: 1st 560Ω, 2nd 180Ω Load (to speed up to get results before Metering and Billing)
Interval reading
Period installed
Original life time calculation
Cell capacity Estimated capacity
Residual discharge(Avg)
Titration(Avg)
Estimated remaining life time
1x per hour(Dutch case)
5 Years 18,5 years
Nominal: 18,3 Ah
Estimated start capacity:
16.97 Ah
13,07 Ah
10 cells: 14,14 AhAfter discharge, titration: 3 cells: 0,86 AhTotal: 15,00 Ah
10 cells: 15,36
Ah
16,7years
10
at hourly reading
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 21.50
22.00
22.50
23.00
23.50
24.00
24.50
Measured idle current (Iavg)
Number of investigated meters
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0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 320.00
5.00
10.00
15.00
20.00
25.00
Measured idle current (Iavg)
Results (2/3); Case Enexis / Flonidan - Pre NTA wireless M-bus-
Batteries only investigated by titration. Wireless gas meters added end of August to battery project.
Transmit interval
Period installed
Original life time calculation
Cell capacity(2 cells parallel)
Estimated capacity now:
Residual discharge (Avg)
Titration(Avg)
Estimated remaining life time
4x per hour
3,5 years
Min 29,3 years
Nominal: 4,8 Ah. Estimated start capacity : 3,8Ah
3,4Ah Not done12 packs (2x AA)3,62 Ah
Between 20-24 years
15
at hourly reading
One meter much higher quiescent current.
First investigation: related to radio hardware.
Further investigation running by Flonidan in
Denmark.
Titration capacity of this cell: 3.316 Ah
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Results (3/3); Case DNWB / Flonidan- Pre NTA wired M-bus-
Interval reading
Period installed
Original life time
Cell capacity Estimated capacity
Residual discharge
Titration Estimated remaining life time
Never Never5 years on stock
25-26 years
Nom: 2,4 AhEstimated start capacity: 1,9Ah
1,55 Ah
1,36 Ah(7 batteries investigated)
4 cells tritration after discharge:Avg 0,63 Ah.
17-21 year
Total remaining: 1,26 + 0,63 = 1,89 Ah
1x per hour(Dutch case)
4,5 years 24 years - same- 1,55 Ah 1,56 Ah 1,94 Ah 17-21 year
Each 20 sec 4 years10-12 years
- same- 1,4 Ah 1,22 Ah 1,56 Ah 6,5 – 7,5 year
15
at hourly reading
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Results (3/3); Case DNWB / Flonidan- Pre NTA wired M-bus-
23
15
at hourly reading
0 5 10 15 20 25 30 35 405
5.5
6
6.5
7
7.5
8
8.5
9
Measured idle current I(avg) Build 2007/2008
Build 2010
Number of investigated meters
Flonidan use 7µA in their life time calculation
0 5 10 15 20 25 30 35 40 45 50 55 600.0
0.5
1.0
1.5
2.0
2.5
3.0Flonidan Pre-NTA Wired M-Bus; Remaining battery capacity
and measurements, accumulative 1-Never; Est. use1-Never; Discharge1-Never; Add. Titration2-20s; Est. use2-20s; Discharge2-20s; Add. Titration3-1h; Est. use3-1h; Discharge4-1h; Est. use4-1h; Titration5-20s; Est. use5-20s; Titration
Battery number
Re
co
ve
red
ca
pa
cit
y /A
h
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Conclusions
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- Investigation after 4-5 years of field operation: At (normal) 1x hour M-Bus operation:
– Flonidan: remaining lifetime wired: > 17 years; Wireless: > 20 years– Landis + Gyr: remaining lifetime > 16 years
Remaining capacity of cells equals to their originally model of lifetime expectation
Real remaining capacity is between residual discharge and titration The number of measurements done is not sufficient enough to conclusively say
something about the influence of aging on power usage.
Within the Smart Metering, this Netbeheer NL battery project:- can form a base which can be repeated by other EU grid operators; - suggested interval period can be 5, 10, 15 years of field operation;- I expect: meter and battery manufacturers are willing to contribute.
- LET’S CONTINUE IN BATTERY RESEARCH with openness in sharing results-
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Questions
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Contact details:
DELTA Netwerkbedrijf B.V.
Machiel Joosse
+31 612 011 921
Tadiran Batteries GmbH
Horst Reuning
+49 (170) 227 0104
