Battery life study - Tadiran Batteries GmbH
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www.modernutilitymanagement.com 75 Tadiran lithium batteries have powered electronic gas meters since the early 1990’s. Today, they are required to run 20 years. For verification, a study 1 was initiated by Netbeheer Nederland where gas meters were taken back from the field after five years of operation. In this study, the residual capacity of the batteries was determined by electrical discharge and chemical titration. Titration is a chemical reaction completely consuming the residual lithium in a battery even if it is not accessible to electrical discharge because of an increase of the internal resistance of the battery. The resulting capacity values (5) matched or exceeded the nominal battery capacity (8) reduced by the consumption of the gas meters (1) and by the self discharge loss (6). Numbers in brackets refer to the chart, where two levels of electrical discharge (3, 4) and titration results are accumulated, on top of each other. Twenty batteries were investigated but, for clarity, the chart shows only the minimum, maximum, and median. Example: the median battery delivered 3.5 Ah to the gas meter. 15.0 Ah were found by electrical discharge in two steps. Titration yielded another 0.3 Ah. A calculated 0.4 Ah were lost to self discharge during field operation. Addition yields a total 19.2 Ah, perfectly matching the nominal capacity and proving that losses were less than anticipated. The electrical current of the meter (2) and the self discharge loss (6) were extrapolated until, after reduction by the calculated impedance loss (9), no residual capacity was left. This corresponds to the anticipated battery life (10), exceeding 20 years. The study should be repeated after ten and 15 years of battery life. BATTERY LIFE STUDY 0 5 10 15 20 25 0 5 10 15 20 25 Capacity /Ah Battery life /years E6V Gas Meter Battery Life Evaluation 1 Actual consumption 2 Anticipated consumption 3 Res. discharge 1 4 Res. discharge 2 5 Titration 6 Self discharge loss 7 Calculated initial capacity 8 Nominal capacity 9 Impedance loss 10 Anticipated battery life Dr. Thomas Dittrich, Tadiran Batteries 1 Machiel Joosse, Horst Reuning: Battery Research Study. How reliable are theoretical battery lifetime calculations compared with reality? Metering Europe 2012, Oct. 9-11, Amsterdam.
Transcript of Battery life study - Tadiran Batteries GmbH
www.modernutilitymanagement.com 75
Tadiran lithium batteries have powered electronic gas meters since the early 1990’s. Today, they are required to run 20 years. For verification, a study1 was initiated by Netbeheer Nederland where gas meters were taken back from the field after five years of operation. In this study, the residual capacity of the batteries was determined by electrical discharge and chemical titration. Titration is a chemical reaction completely consuming the residual lithium in a battery even if it is not accessible to electrical discharge because of an increase of the internal resistance of the battery. The resulting capacity values (5) matched or exceeded the nominal battery capacity (8) reduced by the consumption of the gas meters (1) and by the self discharge loss (6). Numbers in brackets refer to the chart, where two levels of electrical discharge (3, 4) and titration results are accumulated, on top of each other. Twenty batteries were investigated but, for clarity, the chart
shows only the minimum, maximum, and median. Example: the median battery delivered 3.5 Ah to the gas meter. 15.0 Ah were found by electrical discharge in two steps. Titration yielded another 0.3 Ah. A calculated 0.4 Ah were lost to self discharge during field operation. Addition yields a total 19.2 Ah, perfectly matching the nominal capacity and proving that losses were less than anticipated.The electrical current of the meter (2) and the self discharge loss (6) were extrapolated until, after reduction by the calculated impedance loss (9), no residual capacity was left. This corresponds to the anticipated battery life (10), exceeding 20 years. The study should be repeated after ten and 15 years of battery life.
Battery life study
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0 5 10 15 20 25
Capa
city
/Ah
Battery life /years
E6V Gas Meter Battery Life Evaluation
1 Actual consumption2 Anticipated consumption3 Res. discharge 14 Res. discharge 25 Titration6 Self discharge loss7 Calculated initial capacity8 Nominal capacity9 Impedance loss10 Anticipated battery life
Dr. Thomas Dittrich, Tadiran Batteries
1 Machiel Joosse, Horst Reuning: Battery Research Study. How reliable are theoretical battery lifetime calculations compared with reality? Metering Europe 2012, Oct. 9-11, Amsterdam.
