A little known chemical reaction is essential to extended battery life
As remote wireless devices become ubiquitous to the Industrial Internet of Things (IIoT),
there is a growing need to extend battery life, especially for applications involving long-term
deployments in hard-to-access locations and extreme environments.
Certain low-power devices draw average current measurable in microamps with high pulses
measurable in the multi-amp range. These devices are carefully designed to conserve as much
energy as possible to operate for decades on their original battery. This requirement limits the
choice of primary batteries that can be used to deliver long-term power.
Within the lithium family there are a number of primary (non-rechargeable) chemistries,
including iron disulfate (LiFeS2
), lithium manganese dioxide (LiMnO2
), lithium thionyl chloride
(LiSOCl2
), and lithium metal-oxide. (See table on next page) Of all these choices, lithium thionyl
chloride (LiSOCl2
) batteries are overwhelmingly chosen for long-term deployments because
they deliver the highest capacity and highest energy density of all lithium cells to support
product miniaturization. Bobbin-type LiSOCl2
cells also feature an incredibly low self-discharge
rate as low as 0.7% per year, largely due to harnessing the passivation effect, enabling certain
low-power devices to work up to 40 years on the original battery.
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