Fabric-Based Piezoelectric Energy Harvester Relies on Hot Pressing and Tape Casting
Engineers in South Korea have developed a process that could lead to the realization of embedded wearable electronics.
Researchers at the Korea Advanced Institute of Science and Technology (KAIST) have presented a study that describes a highly flexible and sturdy wearable piezoelectric harvester that uses a simple fabrication process involving hot pressing and tape casting.
The research team’s leader, Professor Seungbeom Hong, says that the novelty of their result is thanks to the simplicity, applicability, durability, and its new characterization of wearable electronic devices. The team’s research was published in the September 2020 edition of the journal Nano Energy.
Hot pressing is a method that involves firmly bonding two objects together by applying temperature and pressure. It’s something that has been explored before in the field of energy harvesting, which involves the collection of waste energy and its conversion into electricity.
Hot pressing has traditionally been reserved for the production of batteries and fuel cells due to its high adhesiveness. However, the researchers found that it had a valuable application in producing its piezoelectric harvester. The hot pressing process is also very quick, taking only two to three minutes to complete.
KAIST researchers have developed wearable energy harvesting technology based on high adhesion fabric. Image used courtesy of the Korea Advanced Institute of Science and Technology
To date, fabric-based wearable devices have not yet fully come to fruition due to the complex manufacturing methods in addition to price limitations. There are also concerns surrounding the durability of such devices.
However, according to the KAIST researchers, fabric-based wearables are becoming more important in the fourth industrial revolution due to their connectivity, comfort, and durability. And they’re being used more and more in small electronics and embedded device applications such as sensors and displays.
These challenges, therefore, present a barrier to the widespread adoption of this technology and could stand in the way of further innovation in this field.
High-Throughput Wearable Piezoelectric Energy Harvester
In this study, the KAIST research team claims to have overcome the challenges facing fabric-based wearable piezoelectric devices with their new hot pressing and tape casting fabrication process and analysis technology. Designed for testing the mechanical properties of affordable wearable devices, the device is cost-effective and durable, says the study.
Using hot pressing rather than the typical existing complex processes that would otherwise be required, the team’s manufacturing method combines a conductive polyester fabric and a piezoelectric polymer film.
Fabrication process. Image used courtesy of the Korea Advanced Institute of Science and Technology
This causes the surface of the polymer’s film to become amorphous and the contact surface both sticks to the wide fabric surface and seeps through the woven yarns to form a nail-like shape with high interfacial bonding.
Practical Fabric Based Devices?
There are plenty of possible applications for this technology, a prominent one being the use of sensors powered by energy harvesting wearables connected to the IoT. Creating a fabric-based sensor that’s able to handle data capture, processing, and transmission with minimal energy that can be generated by a piezoelectric harvester could lead to dramatic innovations in fields like medical technology, health monitoring, and fitness tracking.
And according to Professor Hong, the team’s fabric-based wearable piezoelectric energy harvesting manufacturing technology could raise the possibility of “the practical use of fabric-based devices to a new level.”