Bendable Batteries

Battery technology is something I tend to take for granted. Without it, I couldn't run my car or my cell phone or my mp3 player or (heaven forbid) my watch. And the technology has come a long way since its invention in 1800; from Alessandro Volta's expansive setup of electrochemical cells all the way down to those button-sized pieces used in calculators.

As our world is becoming smarter and more mobile, batteries are becoming increasingly important. In the smartphone realm, sadly, batteries are having a tough time keeping pace with the race to the first handheld supercomputer. With bright displays, lots of processing power, and more capabilities in a small and lightweight package, smartphones fly in the face of everything good battery life entails. It's the only thing those flip-phone owners (me) can still brag about (besides lower phone bills).

Efforts to increase battery life usually revolve around finding new ways to decrease power consumption. But a new product in development by LG Chem is taking a different approach. The project is for "cable batteries", batteries made to be flexible like cables or wires. They are designed to work even when tied into knots or bent in any number of ways. The idea is to incorporate these batteries into headphones, phone cases, clothing, jewelry, and other on-person items and accessories in order to help charge or provide power for small electronic devices.

Making the battery starts with thin strands of copper wire coated with nickel and tin - two active electrode materials. The strands are woven into a yarn and formed into a strong spring to serve as the battery's backbone and anode. The other parts of the battery are wound around the anode, including an aluminum wire as the main component of the cathode. Next, the battery is drawn through a slurry containing lithium cobalt oxide cathode material and then dried. After being wrapped in protective layers, the product is completed by pouring in a liquid electrolyte used to carry charge when the battery is hooked up.

Currently, these batteries don't output a ton of energy. IG Chem says a 25 centimeter long prototype can run a small fourth generation iPod shuffle for 10 hours while in its bent shape. But compared to other flexible batteries that have been developed in the past, the discharge of these cable versions is relatively stable under stress. Also, previous types of flexible batteries were mostly made as flat sheets, which severely limitwwed their practical application. Cable batteries offer a lot more creative options for designers.

(A cable-shaped lithium-ion battery powers an LED display even when twisted and strained. Credit: LG Chem)

IG Chem hopes to boost the performance of these batteries as their work continues. Several design aspects, such as new anode materials currently being tested, could significantly increase efficiency and performance. Researchers at the company have high hopes, and say the technology could be ready for mass production in about five years.

I think this type of innovation has a lot of promise, especially for making everyday items "smarter". For instance, wearable electronics have been the focus of efforts to give sportswear the ability to monitor an athlete's health and performance during training. Considering the flexibility of the bendable battery design and the breadth if possibilities, this is just one of the potential applications that could be utilized in years to come.

References

Cable-Type Flexible Lithium-Ion Battery - Advanced Materials

Technology Review