BENDABLE BATTERIES

February 1, 2019


I always marvel at the pace of technology and how that technology fills a definite need for products only dreamt of previously.   We all have heard that “necessity is the mother of invention” well, I believe that to a tee.  We need it, we can’t find it, no one makes it, let’s invent it.  This is the way adults solve problems.  Every week technology improves our lives giving us labor-saving devices that “tomorrow” will become commonplace.  All electro-mechanical devices run on amperage provided by voltage impressed.   Many of these devices use battery power for portability.   Lithium-ion batteries seem to be the batteries of choice right now due to their ability to hold a charge and their ability to fast-charge.

Pioneer work with the lithium battery began in 1912 under G.N. Lewis but it was not until the early 1970s when the first non-rechargeable lithium batteries became commercially available. lithium is the lightest of all metals, has the greatest electrochemical potential and provides the largest energy density for weight.

The energy density of lithium-ion is typically twice that of the standard nickel-cadmium. This is a huge advantage recognized by engineers and scientists the world over.  There is potential for higher energy densities. The load characteristics are reasonably good and behave similarly to nickel-cadmium in terms of discharge. The high cell voltage of 3.6 volts allows battery pack designs with only one cell. Most of today’s mobile phones run on a single cell. A nickel-based pack would require three 1.2-volt cells connected in series.

Lithium-ion is a low maintenance battery, an advantage that most other chemistries cannot claim. There is no memory and no scheduled cycling is required to prolong the battery’s life. In addition, the self-discharge is less than half compared to nickel-cadmium, making lithium-ion well suited for modern fuel gauge applications. lithium-ion cells cause little harm when disposed.

If we look at advantages and disadvantages, we see the following:

Advantages

  • High energy density – potential for yet higher capacities.
  • Does not need prolonged priming when new. One regular charge is all that’s needed.
  • Relatively low self-discharge – self-discharge is less than half that of nickel-based batteries.
  • Low Maintenance – no periodic discharge is needed; there is no memory.
  • Specialty cells can provide very high current to applications such as power tools.

Limitations

  • Requires protection circuit to maintain voltage and current within safe limits.
  • Subject to aging, even if not in use – storage in a cool place at 40% charge reduces the aging effect.
  • Transportation restrictions – shipment of larger quantities may be subject to regulatory control. This restriction does not apply to personal carry-on batteries.
  • Expensive to manufacture – about 40 percent higher in cost than nickel-cadmium.
  • Not fully mature – metals and chemicals are changing on a continuing basis.

One amazing property of Li-Ion batteries is their ability to be formed.  Let’s take a look.

Researchers have just published documentation relative to a new technology that will definitely fill a need.

ULSAN NATIONAL INSTITUTE OF SCIENCE AND TECHNOLOGY:

Researchers at the Ulsan National Institute of Science and Technology in Korea have developed an imprintable and bendable lithium-ion battery they claim is the world’s first, and could hasten the introduction of flexible smart phones that leverage flexible display technology, such as Samsung’s Youm flexible OLED.

Samsung first demonstrated this display technology at CES 2013 as the next step in the evolution of mobile-device displays. The battery could also potentially be used in other flexible devices that debuted at the show, such as a wristwatch and a tablet.

Ulsan researchers had help on the technology from Professor John A. Rogers of the University of Illinois, researchers Young-Gi Lee and Gwangman Kim of Korea’s Electronics and Telecommunications Research Institute, and researcher Eunhae Gil of Kangwon National University. Rogers was also part of the team that developed a breakthrough in transient electronics, or electronics that dissolve inside the body.

The Korea JoongAng Daily newspaper first reported the story, citing the South Korea Ministry of Education, Science and Technology, which co-funded the research with the National Research Foundation of Korea.

The key to the flexible battery technology lies in nanomaterials that can be applied to any surface to create fluid-like polymer electrolytes that are solid, not liquid, according to Ulsan researchers. This is in contrast to typical device lithium-ion batteries, which use liquefied electrolytes that are put in square-shaped cases. Researchers say this also makes the flexible battery more stable and less prone to overheating.

“Conventional lithium-ion batteries that use liquefied electrolytes had problems with safety as the film that separates the electrolytes may melt under heat, in which case the positive and negative may come in contact, causing an explosion,” Lee told the Korean newspaper. “Because the new battery uses flexible but solid materials, and not liquids, it can be expected to show a much higher level of stability than conventional rechargeable batteries.”

This potential explosiveness of the materials in lithium-ion batteries — which in the past received attention because of exploding mobile devices — has been in the news again recently in the case of the Boeing 787 Dreamliner, which has had several instances of liquid leaking lithium-ion batteries. The problems have grounded Boeing’s next-generation jumbo jet until they are investigated and resolved.

This is a very short posting but one I felt would be of great interest to my readers.  New technology; i.e. cutting-edge stuff, etc. is fun to write about and possibly useful to learn.  Hope you enjoy this one.

Please send me your comments:  bobjengr@comcast.net.

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