E-Textiles Power Modules—Removing the Reliance on Conventional Batteries

Whilst research into electronic textiles (e-textiles) has led to ever-increasing levels of functionality and integration, the supply of power is typically limited to the use of conventional rigid batteries. Improved integration enables electronic systems to be hidden within a textile and become invisible to the user but the supply of power has not kept pace with these developments and the reliance on batteries compromises the concealed nature of the system as a whole. Removing the reliance on traditional batteries requires alternative energy supplies and/or textile-based energy storage devices (supercapacitors or batteries).<br/><br/>Power can be supplied by a variety of energy harvesting technologies that can convert ambient sources of energy into electrical power. Sources of power include the kinetic energy associated with the physical displacement of, or strains within, a textile. Thermal energy can be captured from temperature gradients across a fabric and solar energy in the form of light incident on the surface of the fabric can also be harvested. In addition, wireless power transfer (WPT) offers the potential to capture electromagnetic energy. These energy sources could be used to power e-textile systems directly or, more likely, to recharge textile-based energy storage devices.<br/><br/>This talk presents an overview of energy harvesting, WPT and energy storage devices explored at the University of Southampton. Kinetic energy has been harvested from textiles using piezoelectric, ferroelectret and triboelectric transduction mechanisms. Thermal energy harvesting has previously been demonstrated using printed thermoelectric generators. Thin film organic and dye sensitised photovoltaic cells have also been realised on textiles. WPT research includes flexible textile antennas developed to capture radio frequency electromagnetic waves and textile-based coils used to transfer energy using resonant inductive power transfer. Examples of textile-based supercapacitors and batteries will also be presented. Finally, textile power modules that combine mechanical and RF energy harvesting power sources with the textile-based energy storage will be demonstrated. The talk will highlight the challenges and constraints that arise when working with textiles and discuss the future work required remove the reliance on conventional batteries.