Powering Remote Wireless
Devices for 40 years
By Sol Jacobs, VP and General Manager, Tadiran Batteries
Selecting the ideal power management solution is a critical design consideration, especially for remote
wireless devices intended for
use in harsh environments. In
many instances, these devices
are off-the-grid, thus requiring
self-contained power in hard-to-access locations where battery replacement or recharging are not options.
Lithium chemistry remains the preferred choice for remote wireless applications
due to its intrinsic negative potential, which exceeds that of all other metals. The
lightest non-gaseous metal, lithium offers the highest specific energy (energy per
unit weight) and energy density (energy per unit volume) of all available battery
chemistries. Lithium cells are all non-aqueous, and have normal OCVs of between
2. 7 and 3. 6 V. The absence of water allows lithium chemistries to operate in more
While numerous lithium chemistries are available, lithium thionyl chloride
(LiSOCL2) chemistry stands apart due to unique performance attributes that
make it ideal for applications such as electronic toll tags, RFID, environmental
monitoring, SCADA, mil/aero, smart grids, automatic meter reading (AMR), wireless mesh networks, system control and data acquisition (SCADA), data loggers,
measurement while drilling, oceanographic measurement, and emergency/safety
LiSOCL2 batteries are constructed two ways, using spirally wound or bobbin-type construction. Of the two alternatives, bobbin-type Li/SOCL2 cells deliver
the higher energy density (1420 Wh/l) along with higher capacity, as well as the
ability to withstand more extreme temperatures (-55°C to 150°C), with specialized
models adaptable down to cold-chain temperatures of -80°C.
A key attribute of a bobbin-type LiSOCL2 cell is a very low annual self-discharge
rate (less than 1 percent per year), which is crucial to offering 40-year operating
life, as the total lifetime self-discharge of the battery is often greater than the total
amount of energy consumed by the device. Self-discharge is governed
by the chemical composition of the electrolyte, the manufacturing
processes used, as well as mechanical and environmental considerations. Self-discharge can be accelerated by high levels of impuri-ties in the electrolyte, as well as through internal impedance, which
can be controlled by blending special additives into the electrolyte.
High Pulse Applications
Numerous parameters influence the battery selection process,
• Energy consumed in dormant mode (the base current).
• Energy consumed during active mode (including the size,
duration, and frequency of pulses).
• Storage time (self-discharge
during storage dimin-ishes capacity).
• Thermal environments
(including storage and
• Equipment cut-off voltage (as battery capacity
Bobbin-type thionyl chloride (LiSOCL2)
batteries enable remote wireless devices to
operate maintenance-free for up to four decades.