Primary Lithium Batteries for AMI/AMR Systems

Shridhar Pandey, Country Manager
Ramway Technology Co. Ltd.

Nowadays, primary lithium batteries plays a fundamental role in AMI/AMR systems. Because the failure of battery can lead to many problems such as service calls that effects the profit of metering and utility companies and gives the negative impact or impression.

The AMI/AMR system are implemented in remote locations so it is very difficult to reach. Such as ground pits and other unreachable area. So it is difficult or not possible to go and change.

Because of its long life and high energy density utility meters are becoming increasingly complex, so the chemistries of lithium batteries push the limits to deliver high performance without sacrificing the life of the product as a failure in battery can interrupt and disrupt the billing cycle and it results in costly service calls.

BOBBIN TYPE LITHIUM BATTERYFrom all the available lithium batteries chemistries bobbin type Li-SoCl2 Cells offer the advantage of high energy density and voltage, self-discharge rates and excellent service characteristics, higher energy density and voltage.

Bobbin type has two obstacles: passivation after storage at elevated temperature and low current due to low rate designs.

Bobbin Type Lisocl2 Battery
Bobbin Batteries are made by anode formation method.Cathode current collector is connected with porous carbon mixture at center of the battery.

Calculating the use period of primary lithium batteries and their life:
1. Use Time at Constant Discharge Rate
a. Nominal capacity: 1 Ahr Battery
b. Current Value: 5 mA

Using the formula we can calculate use time given below:
Use Time = Nominal Capacity / Use Current    … … … (1.1)
Applying the values in equation 1.1 we get,
Use time = 1 Ah/ 0.05 A
= 200 hrs                                             … … …(1.2)

2. Use Time at Pulse Discharge Condition
Battery Nominal Capacity: 1 Ahr
Base Current = 0.5 mA
1st pulse discharge = 2.5mA per 5 sec
2nd Pulse discharge = 10mA per 1 sec
Discharge cycle continuous for 10 second interval.

Consumption capacity Ahr per cycle is calculated by the formula given below:
Consumption capacity(Ahr) per cycle is = area α + area β + area γ    … … … 2.1

Apply the values in the equation 2.1 we get, consumption capacity per cycle is
= {(0.01 – 0.0025) * 1/3600} +{(0.0025 – 0.0005) * 5/3600} + {0.0005 * 10/3600}
= 0.0000125 Ahr

Now the Use Time is,
Use time [hr] = Cycle Number * Time per 1 cycle
= (Nominal Capacity/ Used Capacity per cycle) * Time[Hr] per cycle
= {(2/0.0000125) * (10/360)}
= 444 hours
So the use time of the battery is 444 hours.

10155164_10202059048974568_265160018_nShridhar Pandey is presently working as a Country Manager with Ramway Technology Co. LTd., China. He has been working on lithium battery technology for AMI/AMR, Smart Meters and Energy Meters. He has introduced Ramway batteries to utility companies and the Indian Market. He has also been successful in writing articles and research papers based on batteries and AMI for various Indian magazines and Journals.