Prof. Menachem: At the same time as recharging faster, the way the battery is built works against flammability danger, making it safer as well.Over a recent 10-day period, laptop manufacturers Apple and Dell announced plans to recall nearly six million lithium-ion notebook PC batteries after nine overheated.
The move highlights the potential hazards of lithium-ion batteries, which power a wide range of other portable devices, including music players and cellphones.
A team of scientists at Tel Aviv University have developed and patented a nano-battery technology for fast charge/discharge batteries that eliminates fire hazards associated with current lithium-based batteries and can provide an alternative source of power for mobile devices.
As semiconductor technology has advanced over recent years, batteries have become the weakest link in the operability of electronic devices according to TAU Prof. Menachem Nathan, head of the university’s Fleischmann Faculty of Engineering, and the head of the nano-battery project.
The growth in power-hungry mobile devices in the marketplace, however, means that manufacturers must substantially increase battery running time by packing more and more power into tighter packages. Moreover, end-users are becoming impatient with the amount of time needed to charge these high power batteries, resulting in a need to design quicker charging devices.
These two characteristics – capacity and speed – have resulted in the development of heavily lithium-loaded batteries that are operated at high temperatures, which can pose a fire hazard. When overheated, Li Ion batteries can burst into flames and pose a major risk to users.
“The problem we’re dealing with here is the flammability of lithium batteries. There have been a few dozen cases – especially in laptops – of them bursting into flames,” Nathan told ISRAEL21c. “It’s not really a new problem, it’s existed since lithium batteries came into being, but it’s only come to the forefront when Apple and Dell made the recall – it became a bit more public.
“The development of our technology wasn’t actually geared to solve the flammability issue – it was just a side effect. Our battery is simply safer due to its structure. We meet another demand of fast charge discharge. With more and more powerful laptops, batteries are quickly discharged. And people are not going to wait a long time to recharge them, they want it done fast. So at the same time as recharging faster, the way the battery is built works against flammability danger, making it safer as well.”
The result of three years of research, the TAU new nano battery technology developed by research teams led by Nathan and by professors Emanuel Peled and Dina Golodnitsky of the university’s School of Chemistry, comprises a substantial number of miniature batteries, about 30,000 on an area as small as one square centimeter, all connected in parallel. This architecture provides a high output of electrical power, without the risk of overheating, a major cause of flammability in laptop computer and other mobile batteries.
“We have thousands of miniature batteries which are interconnected. The basic unit is a 50 micron diameter battery – about the thickness of a strand of hair. In comparison, the diameter of a triple A battery is about three millimeters – ours is.0.03 mm – about a factor of a thousand,” said Nathan.
The research team developed a solution that combines the low internal resistance characteristics of a thin film battery with the high capacity of regular chargeable lithium batteries. Using ingenuous and proprietary coating technologies, tens of thousands of miniature lithium batteries are laid out in parallel within a half mm thick non-conducting substrate.
The nano-battery assemblies were tested in the lab for hundreds of charge/discharge cycles without loss of capacity and stability.
“We succeeded in making a prototype of the batteries – but it’s not more than that at this point. It was developed in a university setting for about a half million dollars – really a drop in the sea,” said Nathan.
The project was spearheaded by Ramot, the technology transfer company of TAU, which coordinates the transfer of new technologies from the university laboratories to the marketplace, by performing all activities relating to the protection and commercialization of inventions and discoveries made by faculty, students and other researchers.
“Ramot has been the leading partner and has raised money to fund the project for three years – which just ended this month,” said Nathan. The technology is quite novel, and we have quite a few patents on it.”
While Ramot is pitching to license the technology, Nathan said there are a number of options available to bring the nano-batteries to market.
“One is to find a strategic partner and continue development together, and the other is to find money on our own and launch a startup. I prefer the first option – to find a strategic partner like Sony or Toshiba,” he said.
“In addition, one special aspect of our technology – although we’re talking about batteries – is that it’s closer to micro electronics. Quite a few processes that we perform use silicon technology. So we’ve been discussing partnering with a couple of major micro electronic firms that see a need for such mini-batteries over the next three or four years.”
Whichever avenue is eventually chosen, it’s likely that safe and powerful nano-batteries will be part of the electronic device world within the next four years, estimates Nathan.