Sol Jacobs, VP and General Manager, Tadiran Batteries
Energy storage is an important concern for remote wireless devices, especially those intended for long-term deployment in hard-to reach places and extreme temperatures. While the vast majority of remote wireless devices are powered by bobbin-type lithium thionyl chloride (LiSOCl2) batteries, a growing number of applications are being powered by energy harvesting technologies in tandem with Lithium-Ion (LI-Ion) rechargeable batteries or supercapacitors to store the harvested energy. An inexpensive consumer-grade rechargeable Li-Ion cell will often suffice if the application is easily accessible, requires a limited operating life (five years and 500 recharge cycles), has a narrow temperature range (0 – 40°C), and does not require high pulses to power advanced, two-way wireless communications.
However, if the energy harvesting application is intended for long-term deployment in a highly remote location where it could be subjected to extreme temperatures, and high pulses are required, then the design engineer should strongly consider an industrial grade Li-Ion battery. These ruggedized cells can operate for up to 20 years and 5,000 full recharge cycles, with an expanded temperature range (-40 to 85°C), and the ability to deliver the high pulses (5 A for a AA-size cell) required for advanced, two-way communications.
Another possibility is to use a supercapacitor. While commonly found in consumer products, supercapacitors are generally not recommended for industrial grade applications due to their inherent limitations, which include bulkiness, linear discharge qualities that do not allow for use of all the available energy, low capacity, low energy density, and high annual self-discharge rates (up to 60% per year). Supercapacitors linked in series also require the use of cell-balancing circuits.
It is always important to choose the ideal power supply based on application-specific requirements, keeping in mind that significant differences exist between consumer-grade and industrial-grade batteries.
Bernt Nilsson, Senior VP of Marketing at COMSOL, Inc.
Renewable energy sources from solar and wind are two major ways that engineers are focusing their efforts towards a greener tomorrow. A challenge with solar and wind energy is that these sources can only be relied on when the wind is blowing or the sun is shining, which aren’t viable alternatives to burning fossil fuels for today’s economy.
New energy technology is being adopted that enables solar power production around the clock, such as Concentrating Solar Power (CSP) plants, which use molten salt for heat transfer as well as storage. Traditionally, CSP plants depended on pipes filled with diathermal oil to absorb solar radiation and were only capable of operating under direct sunlight. Newer plants have extended their operating hours by using molten salt as a medium for storing heat in large well-insulated tanks.
One example of this new technology is the Archimede solar power plant, which was developed through a partnership between Italian utility company ENEL and the Italian National Agency for New Technologies (ENEA). It is the first CSP plant in the world to use molten salt. The Archimede solar plant uses Parabolic Trough CSP technology to generate electricity during sunny hours as well as under overcast conditions or at night.
With emphasis on climate change and the need for renewable energy sources, future power sources will be a combination of advanced conventional and emerging technologies. Engineers are more and more turning to multiphysics simulation to be able to solve systems of equations representing coupled physics effects as they would occur in the real world. Simulation can significantly development time and promote the success of implementing new technologies.