Devices that harvest energy from hand movements or tire pressure sensors that obtain energy from vibration, are two examples of the possible developments.Nowadays, many data capture devices have sensors, with their source of energy. We are surrounded by sensors. Some examples are pressure sensors in the pulse detectors for runners; accelerometers of the cellular phones; sensors in miniaturized medical devices; sensors to detect wifi points; heat sensors for smart cooking; movement sensors; humidity sensors…
Any home or office will easily have several sensors connected to one wireless network. Some estimations say that in 2007 there were ten million sensors in the world, a figure that rose up to ten thousand millions of sensors in 2013. It is said that global network will have trillions –US English trillions- of sensors in the next decade.
“How will be possible to produce batteries for so many devices?”, points out Luis Fonseca, a researcher at the Instituto de Microelectrónica de Barcelona del CSIC. To have them constantly plugged to the grid is not a solution. “Energy autonomy is one of the most desired enabling functionalities in the context of wireless applications. Besides, battery replacement will eventually become economically, environmentally and logistically impractical”.
Luis Fonseca coordinates the European Project SiNERGY. These days the first workshop of SiNERGY is taking place in Bologna. The goal of the project, says Fonseca, is to develop power microgenerators, small devices able to produce small amounts of energy yet high enough to charge the battery of a miniaturized sensor. Scientists will work with silicon-friendly materials, as silicon technologies allow a high density of integration, as well as low cost production of large amounts of miniaturized devices.
It is possible to harvest energy from vibrations, from the heat or from electromagnetic waves. In the project, microharvesters will be coupled with secondary batteries to store energy, so the devices will work even in cases of power demand peaks. Also, the architectures of devices will be improved to maximise energy capture.
Heat, bouncing or vibrations are a source of energy that can feed the intelligent sensors of the future.
The SiNERGY team is working to create a thermoelectric micro-harvester, to convert heat flows into small energy. Also, they are developing an electrostatic and a piezoelectric harvester, to transform vibrations into electric power. In many of these cases, it will be necessary to use nanostructured materials to increase the electrical power of such a small devices. Also, these rechargeable batteries must have a long-life and have to be made with silicon-friendly materials and processes. Scientists are developing micro-batteries of thin layers -in order to reduce their electrical resistivity- and with a high effective surface for enhancing their capacity.
SiNERGY is a VII Frame Program project and has an overall budget of 4.8 million Euros, of which 3.7 are granted by the European Commission. The project consortium is formed by nine partners: the CSIC’s Instituto de Microelectrónica de Barcelona (IMB-CNM), as a coordinator (Spain); the Institut de Recerca en Energia de Catalunya (Spain); the nanotechnology center IMEC (Belgium), the centre Stichting IMEC Nederland, the Università degli Studi di Milano (Italy), the Istituto per la Microelettronica e i Microsistemi of the CNR (Italy); and the companies Electrolux, STE Engineering and Confindustria Emilia Romagna, from Italy.
Web site of the project: SiNERGY(Silicon Friendly Materials and Device Solutions for Microenergy Applications) http://www.sinergy-project.eu/