Stretching Possibilities for Portable Power
Miniaturization in, and cost-reductions of, electronic components such as microprocessors and sensors has been a major boon to the development of wearable electronic devices. However, wearable devices have a common Achilles’ heel — the power supply.
Reading up on the latest advancements in wearables, you will often find fantastic devices, but on closer inspection there is almost invariably a set of wires running off to an external power supply, or a small battery that can only supply enough power for a short duration of operation. This is a major limitation that prevents widespread, practical application of these technologies.
A new innovation in rechargeable lithium-ion battery manufacturing by engineers at MIT may help to pave a new path forward. They have created a battery in the form of an ultra-long fiber that can be woven into fabrics, or even be molded to serve as a structural component of the device itself.
To create these batteries, the team uses a thermal drawing method in which multiple complex electroactive gels, particles, and polymers are drawn through a narrow opening. This shrinks all of the components down to a tiny size, while maintaining the original arrangement of all parts.
These components are housed within a protective, flexible cladding. This particular arrangement has a distinct advantage over previous attempts to build fiber-like batteries in which key components were exposed on the outside of the fiber — these new batteries are inherently stable, durable, and also waterproof.
The researchers employed their methods to create a 140 meter long, 123 milliamp-hour fiber battery. Creating such a lengthy battery shows that there is no apparent limit to the possible length of such a device. The team even believes that kilometer-length batteries are possible.
Members of this research team have previously shown it to be possible to embed various electronic components, such as LEDs, photosensors, communications, and digital systems into fibers. Using similar techniques, they embedded a Li-Fi communications system, a microphone, pre-amp, transistor, and diodes into a 20 meter fiber battery, which is only a few hundred microns in thickness.
This battery was wrapped around the surface of a small submarine drone to provide both power and communications systems. Since the battery also served a structural role in the submarine, it lowered the device’s overall weight, which improved both its efficiency and range.
These batteries are ideally suited for many portable applications, as they are machine washable, flexible, usable underwater, and fire/rupture-safe. These advancements sidestep many of the typical power supply issues with traditional devices and bring us one step closer to pervasive battery-powered electronics.