Efficiency of power conversion is becoming increasingly important across all market segments, including IT, automotive, and industrial manufacturing. As energy costs continue to skyrocket, the efficiency of power delivery systems is becoming a critical attribute to the overall product value. One way to improve electrical efficiency is to extract waste heat from the system and convert a larger portion of that heat into usable energy. This value proposition means that highly efficient thermoelectric components have the potential to play a central role in electronic systems in the future.
The North Carolina Green Business Fund, directed by the North Carolina Board of Science and Technology, awards grants to North Carolina organizations in support of competitively assessed projects focused on attracting and leveraging private sector investments, and on entrepreneurial growth in environmentally conscious clean technology, renewable energy products and businesses.
Nextreme's thin-film embedded thermoelectric generator (eTEG™) generates electricity via the Seebeck effect, where electricity is produced from a temperature differential applied across the device. The Nextreme advantage is a very thin, nano-engineered material that delivers a Seebeck coefficient 150% greater than conventional thermoelectric material.
A unique aspect of Nextreme’s materials is that they can be engineered at a nano-scale, providing improvement options not available in traditional thermoelectric manufacturing processes. The grant from the North Carolina Green Business Fund will be used to optimize the Nextreme thin-film growth process with the goal of doubling the power output of a single device from 250mW to 500mW.
The ability of Nextreme’s thin-film thermoelectric materials to convert waste heat to electrical energy in such a thin, nanoscale form factor positions it uniquely to address market opportunities that standard bulk thermoelectric devices and other energy harvesting or reclamation systems cannot address.
“We are already demonstrating our devices in a number of specialty applications where heat is available and power is required,” said Nextreme CEO Jesko von Windheim. “Increasing Nextreme’s power conversion efficiency will open up a whole new scale of market opportunities.”
Nextreme is currently working with customers in the powering of remote sensors that can monitor equipment and human activities without the use of batteries by simply using energy sources available and harvesting the waste heat to power the sensors. Other applications include thermal batteries that can be used to power implantable medical devices and capturing waste heat from exhaust manifolds to improve fuel efficiency in automobiles.
Nextreme's thin-film thermoelectric products are manufactured in volume with the Thermal Copper Pillar Bump process, an established electronic packaging approach that scales well into large arrays. The Thermal Copper Pillar Bump process integrates thin-film thermoelectric material into the solder bumped interconnects that provide mechanical and electrical connections for today's high performance/high density integrated circuits. Unlike conventional solder bumps, thermal bumps function as solid-state heat pumps on a microscale. The stack-up of a thermal bump, including the thin-film material, solder and electrical traces, is only 100μm (microns) high and has a diameter of 238μm. The thermal bumping process can be implemented at the package-, die- or wafer-level, and is used today to fabricate Nextreme’s discrete modules.