Energy harvesting: Sometimes a battery is a good idea, too

The NanoPower Forum being held this week in San Jose is the first conference I’ve been to that has all the newest energy-harvesting technology in one conference. RF power transfer, vibrational energy harvesting, thermal, piezo – you name it, there’s a paper on it here.

So one of the earliest papers here was from Tadiran batteries. Lou Adams presented data on the longevity and failure rate of lithium/thionyl chloride batteries. These batteries have a lifetime of 20+ years batteries, while supplying about 80mAh/yr The numbers he showed gave a failure rate on the order of1 per million cells over a lifetime of ten years.

Which is impressive. Especially since batteries are hardly gee-whiz energy-harvesting technology. For example, a microgenerator that generates power from machine vibrations might cost $200 — Lou Adams suggested you compare that with a Tadiran battery that might cost $2 and last for 20 years. The poster child application for lithium thionyl choride batteries are automatic meter reading (AMR) – infrequent, predictable transmission instances. Your wireless sensor application may require renewable power, but if it fits the same energy usage profile of AMR, give these batteries a look.

For another viewpoint on batteries and their replacement costs, read Paul Rako’s blog post on automatic meter reading batteries. (And note the comment from the VP of Tadiran.)