Strategic Elements Ltd (ASX:SOR) has achieved another milestone with its self-charging battery technology fabricated onto a flexible textile cloth and mechanically bent over 2000 times.
Current battery technologies (alkaline, coin, lithium) are rigid and bulky and are not suitable for flexible electronics or in very small and thin devices. In early stage work the battery ink technology has shown strong potential to be highly flexible power source for electronics, capable of a very small 6 mm bending radius (e.g. smaller than average adult human finger).
Bending strain is one of the main movements that induces cracks on functional thin films leading to malfunction of flexible electronics. After 2000 bending cycles, the battery ink layer on the textile device was inspected and no visible cracks were present. Voltage output was measured for a two hour period prior to bending and for two hours after bending with minimal change in voltage occurring over the comparative periods.
The self-charging battery ink technology generates electricity from humidity in the air or skin surface. It is being developed under a collaboration partially funded by a Federal Government grant with CSIRO and the University of New South Wales.
The technology is being designed to be a hybrid electric generator – battery cell fabricated with a printable ink. Development to date has been focused on voltage and the ability to harvest energy from humidity in the air. The mechanical flexibility testing results demonstrate another potential competitive advantage of the technology over current battery technologies that are bulky and rigid.
The ability for the high humidity levels of the human skin to be harvested by Battery ink cells and need for a less bulky and flexible power source make the electronic skin patch sector a natural fit for the Battery ink technology. Flexible skin patches are wearable products that have integrated electronic components such as sensors are attached to the surface of the skin. The sector produced US$10 billion in revenue in 2019 and notwithstanding the bulk and rigidness limitations of current batteries and is forecast to grow to nearly US$40 billion by 2030 technology.
Likewise environmental and infrastructure sensors are designed to be built on plastic, glass or wrapped around other curved surfaces require a power source that can conform to curved or flexible surfaces and are also attractive initial user applications. Thus, the initial market focus is on wearables and IoT related devices such as cosmetic, pressure, environmental and health (e.g. diabetes or cardiovascular monitoring) as they have lower energy output requirements. Higher performance applications will include development of a capacitor for energy storage/regulation and focused on at a
Further Development
Early results from UNSW on textile material demonstrates the Battery Ink has a very small bending radius and is a potential power source for current and future flexible electronics. The next steps in mechanical flexibility will involve increasing power output beyond the comparative time period used to date and further optimisation of the fabrication and adhesion properties of the battery ink on other flexible substrates such as plastic.
The company is currently attempting to develop Battery Ink cells up to four times smaller than existing Battery Ink cells. This would demonstrate the potential of the technology to be scaled down in size and open up potential for scaling down even further.
Smaller batteries serially connected can create more power output from the space available within an electronic device. They can also provide ever smaller and lighter devices with an alternate power source.