Tadiran battery technology allows Mueller Systems to offer a 20-year product warranty for its AMI units.
Lithium primary LiSOCL2 cells are constructed two ways: bobbin-type and spiral-wound. Bobbin cells are best suited for AMR/AMI applications because they combine the highest energy density, the highest voltage, a wide temperature range, and an exceedingly low annual self-discharge. Bobbin cells consist of an outer cylinder made of lithium metal and an inner electrode that is reminiscent of a bobbin of thread.
Spiral-wound cells use flat sheets of metal wound around a core, providing a large surface area that can create high currents. The greater number of layers within the spiral-wound cell reduces the volume of electrolyte these batteries can hold, whereas bobbin cells can hold more electrolyte, enabling them to deliver about 30% more energy than spiral cells of equivalent size.
Bobbin-type cells were first used by Aclara (formerly Hexagram) in their earliest generation of AMR meters, which were introduced back in 1984. Millions of these units are still in operation, the earliest of which are still operating on their original Tadiran battery after 27 years in the field. The proven track record of LiSOCL2 batteries allows today’s AMR/AMI equipment manufactures to offer longer term performance contracts that enhance the cost feasibility of large scale infrastructure upgrades.
New Battery Design
AMR/AMI networks are becoming increasingly complex and feature-rich, exemplified by “On Demand” 2-way RF communications that require high current pulses for data gathering and transmission. To address this growing need, Tadiran developed the PulsesPlus™ battery, which combines a standard bobbin-type LiSOCL2 battery with a patented Hybrid Layer Capacitor. This combination allows advanced metering devices to operate continuously with low background current, periodically drawing high current pulses for data capture and transmission, then returning to a low current “sleep” or “standby” state.
Another unique feature of the PulsesPlus battery is its voltage curve, which offers the potential for systems to be programmed with an end-of-life notification that permits preventative maintenance through scheduled battery replacements. The batteries are available in a 3.6V system that indicates when approximately 95% of the battery’s capacity has been exhausted, and a 3.9V system that indicates when approximately 90% of available battery capacity has been used up.
