NEC develops razor-thin battery

It would be used in active RFID cards

News Story by Martyn Williams Taken by: Daniel George
Website: http://www.computerworld.com/printthis/2005/0,4814,106852,00.html

DECEMBER 08, 2005 (IDG NEWS SERVICE) - TOKYO –

Engineers at Japan's NEC Corp. have developed a flexible battery that is less than a millimeter thick and can be charged in half a minute, the company said.

The battery has been designed for use in applications such as active radio frequency identification (RFID) cards and could provide enough power to keep such cards running for several weeks before requiring a recharge, said Yoshimi Kubo, chief manager of fuel cell and battery research at NEC's fundamental and environmental research laboratories yesterday.

The device is an "organic radical battery," a technology developed by NEC that uses materials that are more environmentally friendly than the chemicals found in common rechargeable batteries, the company said. NEC began researching the technology in 2000, and its work has been partly funded by Japan's New Energy and Industrial Technology Development Organization (NEDO).

One of the features of such batteries is their ability to be charged quickly. The device unveiled yesterday can be charged to about 80% of its capacity in about 30 seconds.

A prototype is being demonstrated this week at an NEC event in Tokyo. The battery measures about 4 centimeters square and has been fitted into a card that's about the same size as an identification or credit card. After a charge, it can keep an LED embedded in the card lighted for about 20 minutes before requiring a recharge.

Such thin batteries are important for active-type RFID cards. Most RFID cards or tags are passive devices that aren't capable of transmitting data on their own and work when brought into proximity with a radio field from a tag reader. This typically means they work over a range of several centimeters. Active tags are more like miniature radios and can transmit over longer distances, which means they can be read without having to bring them as close to the tag reader.

NEC said it has no plans for commercial production of the device or an estimate of how much it would cost at such a time as production begins.

It's also not the first organic radical battery application developed by NEC.

A larger version of the battery was shown earlier this year and proposed as a possible future emergency power source for PCs. Because the battery is capable of delivering a large amount of power in a short period, NEC demonstrated it being used to power a PC for about 15 seconds, which is enough time for the PC to back up important data and shut down properly.

That application used four batteries, each of which measure 55 by 43 millimeters and are 4mm thick, which is about the same size as a stack of three credit cards. Each cell weighs 20 grams. Like the prototype on show this week, NEC didn't have any immediate commercialization plans for the technology.