Ultrasound to recharge body devices
The number of patients using implanted electronic devices, such as artificial pacemakers and defibrillators, is increasing worldwide with the aging of the population and the advancement of medical technology. Currently, the batteries for devices implanted in the body are replaced through an incision operation, which can lead to health complications. As a result, a new wireless charging technique for energy transfer is being developed that can be used to charge implanted devices in the body without surgery. This same technology can also be used to charge the batteries of underwater devices, such as sensors, which are used to monitor the condition of underwater cables.
The Korea Institute of Science and Technology (KIST, President: Seok- Jin Yoon) announced that a research team led by Dr. Hyun-Cheol Song at the Electronic Materials Research Center has developed ultrasonic wireless energy transmission technology that can be applied in the research areas mentioned above.
Electromagnetic induction (EM) and magnetic resonance can be used in wireless energy transfer. EM induction is currently used in smartphones and wireless earphones; however, its use is limited because EM waves cannot pass through water or metal, resulting in a short charging distance. Furthermore, this method cannot be easily used to recharge implanted medical devices as the heat generated during recharging is harmful. The magnetic resonance method requires that the resonance frequencies of the magnetic field generator and the transmitting device are exactly the same; furthermore, there is a risk of interference with other wireless communication frequencies, such as Wi-Fi and Bluetooth.
credits: Korea Institute of Science and Technology The KIST team, therefore, has adopted ultrasonic waves as a means of transmitting energy, instead of EM waves or magnetic fields. Sonar, which uses ultrasonic waves, is commonly used in underwater environments and the safety of the use of ultrasonic waves in the human body has been ensured in various medical applications, such as the diagnosis of organs or fetal conditions. However, existing acoustic energy transfer methods are not readily commercialized due to the low transmission efficiency of acoustic energy. The research team has developed a model that receives and converts ultrasonic waves into electrical energy. using the triboelectric principle which allows the conversion of small mechanical vibrations into electrical energy effectively. By adding a ferroelectric material to the triboelectric generator, the ultrasonic energy transfer efficiency was significantly improved from less than 1% to more than 4%. In addition, it is possible to charge over 8 mW of power at a distance of 6 cm, which is sufficient to simultaneously operate 200 LEDs or to communicate data from the Bluetooth sensor underwater. Furthermore, the newly developed device has a high energy conversion efficiency and generates marginal amounts of heat.
