Autonomous Wireless Sensors

The ideal wireless sensor node (WSN) is small and lightweight, has sufficient power for accurate sensor readings and processing capability, can reliably transmit over useful distances, and is able to operate autonomously with zero maintenance for the life of the application. The number one inhibitor to achieving each of these ideal characteristics is the power source. Conventional batteries with organic liquid or polymer electrolytes only last a few years, and are very bulky. Supercapacitors have more than sufficient pulse power, but suffer from poor energy density and have very high leakage currents. Because supercaps hold so little energy, each data transmission of a WSN consumes a significant percentage of the supercap's energy, which is counted as a "cycle." If a sensor transmits every second, the supercap must cycle approximately 30,000,000 times in just one year.

THINERGY MECs are fundamentally different and provide the best solution for each of the wireless sensor node challenges. An MEC typically smaller than the devices they power, so they do not define the system form factor like other batteries or supercaps. As the world's most powerful battery for its size, MECs are unrivaled in their ability to provide high pulse current combined with ample energy density in a single device. Therefore, they can power the entire WSN (sensor, µP, radio, etc.), without the aid of additional capacitors, for days, weeks or months, on a single charge, depending on the duty cycle. When combined with ambient energy harvesting and IPS' patent-pending Passive Power Management Unit (PPMU™) electronics, a postage stamp sized MEC can autonomously power a WSN for decades. With their unprecedented cycle life of >10,000 full depth recharge cycles, and >100,000 shallow discharge cycles, the MEC will typically outlive the application it is powering. Since the capacity of the cell is so much higher than a supercap, typical transmit cycle of a WSN radio chip takes only about 0.002% of the energy of the cell. It takes about 40,000 transmit events of a typical WSN to be counted as a "cycle", which means the MEC can typically survive >400,000,000 transmit events, from a single MEC101-type cell. Stacking cells (electrically connected in parallel) further increases the capacity without increasing the footprint, and further increases the number of transmit events that can be performed on a single charge, and the cycle life of the device. With their all solid-state construction and inorganic electrolyte, THINERGY Micro Energy Cells have a typical self discharge rate of <10nA, operate over an extremely broad temperature range (-40°C to +85°C), and offer decades of maintenance-free service life for all forms of wireless sensor nodes. The ideal battery for the ideal WSN has arrived.