One man’s solution to micromachines’ power problem looks good on paper

KIBBUTZ EINAT, Israel, June 27, 2001 — If Baruch Levanon has his way, billions of batteries may soon be rolling off the printing presses just like your morning newspaper.

Levanon is chief executive of Power Paper Ltd., a start-up company located in Kibbutz Einat, a communal settlement just outside Tel Aviv, Israel. His company has patented a process of mass-producing batteries on any thin, flexible substrate — even paper.

Baruch Levanon, chief executive of

Power Paper Ltd. In Israel, conceived

of paper-thin power sources while

designing a drug delivery patch for

a pharmaceutical company in the

early 1990s.

Experts are unsure whether such a power source would solve the problem of how to deliver power to micro and nanoscale devices — one of the biggest impediments to further development of small technology. Nevertheless, application development is already under way, and Levanon believes it is just a matter of time before his slender batteries are used to power applications ranging from smarter smart cards to MEMS-driven health-care devices.

“Thin and flexible microelectronics is the vision of Power Paper,” he says. “The idea is that today, with increasing miniaturization and microelectronics getting smaller and smaller, you can really take it one step further to the thickness of paper.”

The 52-year-old Levanon, once an aeronautic engineer, first conceived of paper-thin power sources while designing a drug delivery patch for a pharmaceutical company in the early 1990s. These patches included a small microprocessor and minipump to regulate injections. But they were bulky and uncomfortable, and the batteries were the culprit.

“This was the drive for Power Paper,” says Levanon, explaining how he set out to create a battery that would be “totally integrated” into a device. Ultimately, these batteries could turn such a device into a flexible patch, embedded with a MEMS syringe, says Levanon, waving a Band-Aid-like dummy.

Levanon worked on the concept between 1995 and 1997. After his batteries reached practical performance levels and a patent was secured, he set up Power Paper with $1.5 million in venture capital. He has since filed for dozens of patents for applications. Power Paper received another $3 million financing round in 1998 and recently closed another undisclosed round.

Power Paper’s batteries stuck to conventional battery-making architecture yet also broke the mold — literally. The batteries are 0.5mm thick and made of five layers of material, a cathode on one side, anode on the other, two layers of conductors in between and an electrolyte core. But unlike conventional batteries, its secret formula allows it to function without a bulky metal casing. Despite the exposure, it is also environmentally friendly and boasts a shelf life of 2.5 years.

Levanon claims that competitors — including traditional battery companies and ECR – Electrochemical Research Ltd., another Israeli group, have made smaller rechargeable batteries but they are still stuck inside inflexible metal casings.

Power Paper’s batteries are not yet rechargeable, but with 1.5 volts and a capacity of almost 20mAh (milliamps per hour) per square inch, they are similar to coin-sized conventional batteries used in watches and calculators. They can also be designed to take up more area and produce more power. Still, it is currently not suitable to power-hungry applications like cellular phones.

Later this year, the batteries will already be invisibly on the market inside novelty items such as electronic greeting cards and mousepads, which are being produced at the company’s Hong Kong subsidiary.

But Levanon gets much more excited talking about potential applications for smart cards, smart tags and health-care devices.

Together with KSW Microtec, a German microelectronics company, Power Paper has developed precision heat-sensitive tags. These could be used to monitor the temperature on blood bags when they are transferred to hospitals, saving shipments that often are trashed due to temperature fluctuations.

Credit cards equipped with a thin-screen that could display account information are also a potential application.

Levanon also hopes to see over-the-counter health-care applications on the shelves by 2003, though drug-delivery applications involving other types of medicines will require FDA approval and will take longer. In the future, tiny MEMS syringe systems could inject drugs at specific dosages.

For all applications, the key to commercial success is the printing production process, which allows the batteries to be produced for just a few cents apiece, depending on the design.

Small tech experts agree that power is a barrier to shrinking devices. According to Stephen Casalnuovo, technical staff member at Sandia National Laboratories in Albuquerque, N.M., power remains one of the “outstanding problems” in building microsystems.

“You can build MEMS, microdevices, microsensors and integrated circuits the size of a fingernail, but when it comes down to how are you going to power them, the battery becomes the largest component of the system and it wears down first,” he says.

The problem can be demonstrated, he says, by looking at the MEMS device inside airbag sensors — powered by a fat car battery.

Although some researchers are trying to integrate batteries into silicon wafers and MEMS, Casalnuovo points out that smaller batteries also means smaller capacity. These techniques are “limited by a chemistry”, he explains, which is why researchers are also working on energy harvesting techniques such as solar cells.

Professor Kenneth Snowdown, director of the Centre for Nanoscale Science and Technology at the University of Newcastle upon Tyne, a leading UK research institute, says power is “an annoyance” to researchers. “The ultimate challenge for nanotechnology is to try and harness the environment and to hijack or steal power in much the same way as miniature components do in living systems in the human body,” he says.

Levanon argues that thin batteries can help solve the problem by being more easily integrated into the shape of a MEMS product — even if not down to the size of a microdevice.

Related story: Instant circuit: Just add nanoparticles and hit ‘print’


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