Sub-Watt energy harvesting is moving into the mainstream thanks to technological advances and convergence with ultra-low power microelectronics and wireless communications systems.
The rise of the Internet of Things (IoT) and Machine-to-Machine (M2M) provide a framework for better energy efficiency and overall resource efficiency through pervasive sensor based information about virtually anything and any environment.
Battery maintenance, however, can seriously limit where sensors can be practicably deployed. Temperature differences are almost as pervasive as useful sensing opportunities, so harvesting energy from this omnipresent source is offering a solution to the battery problem.
This is where thermoelectric generators (TEG) come in. TEGs work by converting temperature differences between two surfaces of a semiconductor into electric voltage using the Seebeck effect. The first generation of these devices came around in the 1960s for use in industrial applications – for example in power plants where they’d convert waste heat into electricity.
The development of new manufacturing techniques has enabled a new generation of TEGs to be developed. Whilst these thin-film microTEGs only generate a small electrical charge it’s enough to operate the ultra-low power sensors that make up IoT and M2M networks. MicroTEGs radically alter where sensors can be deployed – particularly for wearable technologies where the heat of the human body against the ambient environment provides the temperature differential to generate electricity.
Thermoelectric generators are built on a substrate that needs to be electrically isolating whilst being as thermally conductive as possible. For applications such as wearables it also needs to be flexible tomaintain contact with the skin. This has created a headache for TEG manufacturers as the standard flexible substrate material is polyimide – a very poor thermal conductor. Nanotherm are working with leading TEG manufacturers to develop Nanotherm Flex for TEG applications. Nanotherm Flex uses our patented ECO process to convert the surface of a thin aluminium foil into a nanoceramic dielectric material. This provides dielectric properties along with exceptional thermal conductivity whilst maintaining the flexibility of the aluminium foil. Nanotherm Flex offers a step change in the thermal conductivity of flexible substrates enabling far more power to be generated by the TEG for its footprint.
Nanotherm are currently sampling Nanotherm Flex for micro thermoelectric generator applications with lead customers. If you’d like more information on how you could use Nanotherm Flex in your application please call us on +44 01440 765520 or send us an email.